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1. Comparative study of the various methods of preparation of silicate solution and its effect on the geopolymerization reaction

Author: Sylvie Rossignol, N. Essaidi, Laurent Ulmet, L. Laou, Sylvie Yotte, Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM)
Subjects: Metakaolin reactivity, Materials science, 0211 other engineering and technologies, General Physics and Astronomy, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, Physics and Astronomy(all), Alkaline solution, chemistry.chemical_compound, Aluminosilicate, Bricks, 021105 building & construction, Binders, Fourier transform infrared spectroscopy, Brick, Depolymerization, Silicate powder, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Silicate, lcsh:QC1-999, Characterization (materials science), Geopolymer, [CHIM.POLY]Chemical Sciences/Polymers, Polymerization, Chemical engineering, chemistry, 0210 nano-technology, lcsh:Physics
Abstract: This paper is based on the characterization of synthesized geopolymer binders based on either powder or solution silicate, and the amount of water contained in synthesized binders is determined to evaluate their possibility to coat a brick. The structural evolution of the formed geopolymers was investigated using FTIR spectroscopy. The mechanical properties were evaluated using compression tests. The structural evolution ensured that the solutions prepared from silicate powder or liquid had different degrees of polymerization, which modified the polycondensation reaction of the mixture. Nevertheless, the use of aluminosilicate solutions based on powder or liquid display similar behavior in a polycondensation reaction. The obtained materials show good mechanical properties, and it is possible to deposit this binder on the brick depending on the water content. Keywords: Silicate powder, Bricks, Alkaline solution, Binders, Depolymerization, Metakaolin reactivity
Published: 2016
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2. Formulation of new materials based on geopolymer binders and different road aggregates

Author: Fatima Allou, Joseph Absi, Sylvie Rossignol, Christophe Petit, Nadine Tenn, Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)
Subjects: chemistry.chemical_classification, Materials science, Base (chemistry), Road construction, Process Chemistry and Technology, Sodium, Potassium, 0211 other engineering and technologies, New materials, chemistry.chemical_element, 020101 civil engineering, [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, 0201 civil engineering, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Diorite, Geopolymer, chemistry, Asphalt, 021105 building & construction, Materials Chemistry, Ceramics and Composites, Composite material, ComputingMilieux_MISCELLANEOUS
Abstract: The study of bitumen substitution in the field of road construction is necessary to overcome the effects of limited oil resources and economic problems. The elaboration of new materials based on geopolymer binders and aggregates was investigated in this work. Two series of formulations of geopolymer binders based on sodium or potassium were prepared with the incorporation of granite or diorite. The formulation of these binder was investigated by the study of (i) the effect of the nature of the alkaline solution by modify the pH value with base and (ii) the mass percentage of the incorporated aggregates. The time evolution study shows different aspects of the synthesized materials, which depend essentially on the composition of the activating solutions and the nature of the alkaline solutions. The formulations using these ratios (Si/Na=1.55; Si/K=1.94 and 2.96) appear the best. Moreover, it was evidenced that materials based on the potassium alkaline solution present a consolidated aspect faster than the materials based on the sodium alkaline solution. Additionally, it is possible to incorporate diorite or granite until 60 w% with some formulations. These various formulations are promising to be use not as a substitute of bitumen but in addition between bitumen and ground.
Published: 2015

3. Effect of the addition of ammonium molybdate on metakaolin-based geopolymer formation: Shrinkage and crystallization

Author: M. Colas, Laeticia Vidal, Emmanuel Joussein, Joseph Absi, Sylvie Rossignol, Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)
Subjects: Ammonium molybdate, General Chemical Engineering, Inorganic chemistry, chemistry.chemical_element, [CHIM.MATE]Chemical Sciences/Material chemistry, Microstructure, law.invention, Geopolymer, symbols.namesake, chemistry, Chemical engineering, law, Molybdenum, symbols, Crystallization, Raman spectroscopy, ComputingMilieux_MISCELLANEOUS, Metakaolin, Shrinkage
Abstract: This paper focuses on the influence of the addition of ammonium molybdate to geopolymer mixtures to better understand the formation of geopolymer structural networks and the effect of Mo-based additive on the thermal behavior of material. Several geopolymers were synthesized between two metakaolins and various amounts of ammonium molybdate. The microstructure of samples was determined by SEM, the structural evolution (depending on the amount of molybdenum added) was investigated using Raman spectroscopy and XRD analyses, and the temperature behaviors of materials by DTA–TGA and dilatometric analyses. The results showed that (i) both metakaolins react differently in the presence of ammonium molybdate, (ii) molybdenum induces decrease of shrinkage value at high temperatures, and (iii) the crystallization seems to be favored with ammonium molybdate. This work shows that ammonium molybdate controls polycondensation reactions highlighting the modifier or former role played by the molybdenum atoms depending on the amount of ammonium molybdate added.
Published: 2015

4. Effects of microstructure on acoustical insulation of gypsum boards

Author: Yassine Elkhessaimi, Nicolas Tessier-Doyen, A. Smith, Axe 1 : procédés céramiques (SPCTS-AXE1), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), IRCER - Axe 1 : procédés céramiques (IRCER-AXE1), Institut de Recherche sur les CERamiques (IRCER), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)
Subjects: Materials science, Gypsum, Sound transmission class, Loss factor, 0211 other engineering and technologies, Modulus, Glass wool, 02 engineering and technology, Sandwich panel, engineering.material, [SPI.MAT]Engineering Sciences [physics]/Materials, 021105 building & construction, Architecture, Composite material, Safety, Risk, Reliability and Quality, ComputingMilieux_MISCELLANEOUS, Civil and Structural Engineering, [PHYS]Physics [physics], Building and Construction, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Microstructure, [PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph], Core (optical fiber), Mechanics of Materials, engineering, 0210 nano-technology
Abstract: This paper focusses on the understanding of microstructural effects related to sound transmission loss and critical frequency of gypsum boards. The determination of the critical frequency, through measurements of the mass per unit area, thickness and Young's modulus, indicates that a microstructure exhibiting large gypsum crystals with prismatic shapes obtained by addition of citric acid, yields a value (for example: ≅ 3700 ± 360 Hz for 1.5 mass% of citric acid additive, board thickness: 14 mm) well beyond the sensitive frequency range of human hearing (350–1500 Hz). Concerning the sound transmission loss, acoustic insulation can be significantly improved by both increasing (i) the mass per unit area of the gypsum board, (ii) the thickness and (iii) the loss factor. A sandwich panel consisting of an assembly of two individual gypsum boards prepared with citric acid combined with a glass wool core of 50 mm in thickness shows very promising insulating performances. This result has been predicted theoretically with a transfer matrix method.
Published: 2017

5. Quantification of self-heating and its effects under cyclic tests on a bituminous binder

Author: Joseph Absi, Ebrahim Riahi, Ramón Botella, Christophe Petit, Frédéric Dubois, Fatima Allou, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 2 : procédés plasmas et lasers (SPCTS-AXE2), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: Work (thermodynamics), Thixotropy, Materials science, 0211 other engineering and technologies, Modulus, Aggregate modulus, 02 engineering and technology, Industrial and Manufacturing Engineering, [SPI.MAT]Engineering Sciences [physics]/Materials, stomatognathic system, 0203 mechanical engineering, 021105 building & construction, Dynamic modulus, General Materials Science, Composite material, ComputingMilieux_MISCELLANEOUS, Bulk modulus, business.industry, Flexural modulus, Mechanical Engineering, technology, industry, and agriculture, Dynamic mechanical analysis, Structural engineering, [CHIM.MATE]Chemical Sciences/Material chemistry, musculoskeletal system, 3. Good health, 020303 mechanical engineering & transports, Mechanics of Materials, Modeling and Simulation, business
Abstract: This paper studies the reduction in complex modulus when a bituminous binder is subjected to the fatigue test, along with the ability of this material to recover such a loss in modulus. It has been demonstrated in the literature that during a fatigue test, a rapid and reversible decrease of complex modulus can be observed at the beginning of the test. This reversible decrease is not correlated with fatigue and has been explained by the existence of reversible phenomena, such as thixotropy, self-heating, nonlinearity, etc. The aim of this work is to quantify the self-heating and determine its share in the reversible reduction of complex modulus under cyclic loading. A strain sweep test has been developed with different loading steps, followed by rest periods after each loading phase. The loading level increases with each step, and the loading phases allow observing the modulus decrease, while the rest periods are introduced to observe modulus recovery after each loading level. A complete recovery of modulus means that the modulus diminution is due to a reversible phenomenon however a partial recovery of modulus notifies the presence of nonreversible phenomenon (such as damage). In using this approach, the influence of loading level on both complex modulus decrease and recovery can be examined. In order to quantify self-heating during testing, the sample temperature is measured by embedding a thermocouple probe inside the sample during its manufacturing. To obtain the relationship between complex modulus and temperature, the complex modulus test results have been interpreted herein. A thermoviscoelastic numerical simulation was conducted to determine the temperature field in the material and quantify the variation in complex modulus with respect to self-heating. Results show a temperature variation of 11 °C inside the sample. A comparison between experimental and numerical results indicates that the numerical model perfectly predicts the variations in both temperature and complex modulus until a certain strain level, where the damage, thixotropy or other factors have not appeared yet. It is also observed that the reversible complex modulus decrease can be explained by self-heating.
Published: 2017

6. Modelling self-heating and thixotropy phenomena under the cyclic loading of asphalt

Author: Joseph Absi, Christophe Petit, Fatima Allou, Frédéric Dubois, Ebrahim Riahi, Félix Pérez-Jiménez, Ramón Botella, Fateh Fakhari Tehrani, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, Universitat Politècnica de Catalunya. MATCAR - Materials de Construcció i Carreteres, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 2 : procédés plasmas et lasers (SPCTS-AXE2), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: Thixotropy, Materials science, heterogeneous simulation, 0211 other engineering and technologies, Modulus, 02 engineering and technology, Viscoelasticity, thixotropy, Matrix (geology), [SPI.MAT]Engineering Sciences [physics]/Materials, 0203 mechanical engineering, Paviments d'asfalt -- Assaigs de materials, 11. Sustainability, 021105 building & construction, Thermal, Composite material, ComputingMilieux_MISCELLANEOUS, viscoelasticity, Civil and Structural Engineering, business.industry, self-heating, dissipated energy, [CHIM.MATE]Chemical Sciences/Material chemistry, Dissipation, Asphalt concrete, 020303 mechanical engineering & transports, Asphalt, business, Enginyeria civil::Infraestructures i modelització dels transports::Transport per carretera [Àrees temàtiques de la UPC], Asphalt concrete--Testing
Abstract: This is an Accepted Manuscript of an article published by Taylor & Francis Group in Road Materials and Pavement Design on 2017, available online at: http://www.tandfonline.com/doi/abs/10.1080/14680629.2017.1305145. Asphalt concrete is a heterogeneous material containing a viscoelastic bituminous matrix and elastic aggregates. When testing asphalt materials under cyclic loading, various phenomena (so-called biasing effects) can decrease the modulus. This effect has been explained by an increase in the temperature of materials due to energy dissipation (self-heating), thixotropy and damage. The aim of this study is to analyse a uniaxial cyclic tension-compression test performed on bitumen and asphalt mixes, in modelling self-heating as one of the biasing effects. To quantify the self-heating and dissipated energy (as a heat source), a heterogeneous thermomechanical approach is introduced by separating the viscoelastic bituminous matrix from the elastic aggregates. According to this approach, various processes such as energy dissipation in the matrix due to viscoelastic properties, the thermal sensitivity of the matrix as well as its capacity to develop a heat source and diffuse heat through aggregates can all be studied. Local temperature variations are calculated by considering the heterogeneous dissipated energy field as a heat source. The complex modulus variation can then be calculated by taking into account both the temperature field and thermal sensitivity of the material. Simulation results show that as opposed to bitumen, in which 100% of complex modulus variations observed during a strain sweep test are due to self-heating, the results on asphalt mixes indicate that thixotropy varies with mechanical properties to a greater extent than self-heating. This fact is probably correlated with a higher strain level in thin bituminous matrix films, a higher load velocity in thin matrix films, material heterogeneity, and the 3D characteristic of matrix loading during the tension-compression test on asphalt mixes.
Published: 2017

7. Durability testing of an iodate-substituted hydroxyapatite designed for the conditioning of 129I

Author: Sylvie Rossignol, Antoine Coulon, Danielle Laurencin, Lionel Campayo, Agnès Grandjean, Patrick Jollivet, Laboratoire d'études de Matériaux Céramiques pour le Conditionnement (LM2C), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire des Procédés Supercritiques et de Décontamination, Commisariat de l'Energie Atomique, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Laboratoire d'Etudes du Comportement à Long Terme des matériaux de conditionnement (LCLT), Département de recherche sur les technologies pour l'enrichissement, le démantèlement et les déchets (DE2D), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Département de recherche sur les Procédés et Matériaux pour les Environnements complexes (DPME), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), CEA-Direction de l'Energie Nucléaire (CEA-DEN), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction de l'Energie Nucléaire (CEA-DEN)
Subjects: Nuclear and High Energy Physics, Metal ions in aqueous solution, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, Iodine, 01 natural sciences, 7. Clean energy, Apatite, chemistry.chemical_compound, conditioning, 0103 physical sciences, General Materials Science, Dissolution, ComputingMilieux_MISCELLANEOUS, Iodate, 010302 applied physics, Chemistry, iodine, Metallurgy, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Phosphate, 6. Clean water, Nuclear Energy and Engineering, 129I, visual_art, apatite, visual_art.visual_art_medium, radioactive waste, Leaching (metallurgy), 0210 nano-technology, Stoichiometry
Abstract: The safe management of iodine coming from spent nuclear fuels by storage in deep geological repositories requires durable materials. For this purpose, we have recently developed an iodate-substituted hydroxyapatite (HA-CaI). In the present article, the chemical durability of this material is assessed as a function of leaching media and apatite stoichiometry. First, the maximum rate for iodine release was determined in unsaturated conditions leading to a congruent dissolution of HA-CaI. In these conditions, the forward rate was equal to 2 × 10 −2 g m −2 d −1 at 50 °C independently of apatite stoichiometry. During this regime, dissolution was controlled by surface reaction and diffusion phenomena. When concentrations of calcium and phosphate ions in solution increased, the system became saturated towards non-substituted hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 and the rate of iodine release consecutively decreased. Consequently, tests were carried out to determine the behaviour of HA-CaI in such experimental conditions (saturated conditions), which were thought to be time-prevalent given the half-life of 129 I (15.7 million years). During this regime, also called residual regime, iodine was released in the solution at a constant rate without being trapped in a secondary phase. The residual rate at 50 °C on the basis of iodine release was of 10 −4 g m −2 d −1 in an initially deionized water, and it fell by one order of magnitude (r = 10 −5 g m −2 d −1 ) in a clay-equilibrated groundwater (hereafter called Callovo-oxfordian (COx) groundwater). This singular behaviour was ascribed to the presence of calcium in COx water. These preliminary results on the chemical durability of HA-CaI suggest that this material is a viable candidate as repository iodine waste form.
Published: 2017

8. Effect of aging and alkali activator on the porous structure of a geopolymer

Author: Jacques Jestin, Prune Steins, Sylvie Rossignol, David Lambertin, Arnaud Poulesquen, Fabien Frizon, Olivier Diat, Jérémy Causse, Département d'études du Traitement et du Conditionnement des Déchets (DTCD), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Laboratoire d'Etudes de l'Enrobage des Déchets (L2ED), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'energie Atomique et aux Energies Alternatives, Ions aux Interfaces Actives (L2IA), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Nanomatériaux pour l'Energie et le Recyclage (LNER), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: porosity, Materials science, Mineralogy, small- and wide-angle X-ray scattering, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, alkali activators, General Biochemistry, Genetics and Molecular Biology, geopolymers, Aluminosilicate, Specific surface area, Porosity, Metakaolin, nitrogen sorption, small-angle neutron scattering, aging, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Alkali metal, Microstructure, Small-angle neutron scattering, 0104 chemical sciences, Geopolymer, Chemical engineering, 0210 nano-technology
Abstract: International audience; Nitrogen sorption and small- and wide-angle X-ray and neutron scattering techniques were used to study the porous structure of geopolymers, inorganic polymers synthesized by reaction of a strongly alkaline solution and an aluminosilicate source (metakaolin). The effects of aging and the use of alkali activators (Na+, K+) of different sizes were investigated at room temperature. The influence of aging time on the microstructure of both geopolymer matrixes was verified in terms of pore volume and specific surface area. The results suggested a refinement of the porosity and therefore a reduction in the pore volume over time. Regardless of the age considered, some characteristics of the porous network such as pore size, shape and distribution depend on the alkali activator used. Whatever the technique considered, the potassium geopolymer has a greater specific surface area than the sodium geopolymer. According to the scattering results, the refinement of the porosity can be associated with, first, a densification of the solid network and, secondly, a partial closure of the porosity at the nanometre scale. The kinetics are much slower for the sodium geopolymer than for the potassium geopolymer in the six months of observation. © 2014 International Union of Crystallography.
Published: 2014

9. Mechanical behavior of asphalt mixture based on X-ray computed tomography images and random generation of aggregates skeleton

Author: F Courreges, F. Fakhari Tehrani, Christophe Petit, Joseph Absi, Axe 2 : procédés plasmas et lasers (SPCTS-AXE2), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Conservatoire National des Arts et Métiers [CNAM] (CNAM), Ifsttar, Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Aggregate (composite), business.industry, 0211 other engineering and technologies, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Microstructure, [SPI.MAT]Engineering Sciences [physics]/Materials, Asphalt concrete, Asphalt, 021105 building & construction, Dynamic modulus, Volume fraction, Composite material, Deformation (engineering), 0210 nano-technology, Material properties, business, ComputingMilieux_MISCELLANEOUS
Abstract: International audience; The microstructure of an asphalt mix is influenced by the aggregate content, orientation and contacts. In several previous studies, the asphalt concrete is treated as homogeneous material and its microstructures are ignored. However, it has been reported that the deformation and strength of asphalt concrete are not only influenced by volume fraction of its components but also affected by the spatial distribution of its microstructures. Thus, to investigate the mechanical behaviors of asphalt concrete, it is imperative to notice more accurately a micromechanical model containing information of components and microstructures. The objective of this study is to investigate the influence of the microstructure characteristics on the mechanical behaviour of asphalt mixes. The details of the microstructure are obtained by X-ray computed tomography (CT). A comparison with results issues from digital models of random aggregate generation will be considered. The dynamic modulus of the matrix and elastic properties of aggregates were introduced as input parameters into numerical models qualified by heterogeneous microstructure. Finally, the influence of the microstructure on the mechanical response of material at local level is also highlighted.
Published: 2016

10. Numerical simulation of local temperature evolution in bituminous materials under cyclic loading

Author: C. Petit, Joseph Absi, Laurent Ulmet, Fatima Allou, Frédéric Dubois, Ebrahim Riahi, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 2 : procédés plasmas et lasers (SPCTS-AXE2), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Environmental Engineering, Materials science, heterogeneous simulation, 0211 other engineering and technologies, 02 engineering and technology, Viscoelasticity, [SPI.MAT]Engineering Sciences [physics]/Materials, Matrix (mathematics), 0203 mechanical engineering, 021105 building & construction, Thermal, medicine, Composite material, asphalt concrete, viscoelasticity, cyclic loading, Civil and Structural Engineering, Computer simulation, business.industry, self-heating, Stiffness, dissipated energy, [CHIM.MATE]Chemical Sciences/Material chemistry, Dissipation, Asphalt concrete, [SPI.GCIV]Engineering Sciences [physics]/Civil Engineering, 020303 mechanical engineering & transports, Asphalt, medicine.symptom, business
Abstract: International audience; Asphalt concrete is a heterogeneous material containing a viscoelastic bituminous matrix and elastic aggregates. During fatigue testing in the laboratory, the material stiffness decreases as a result of increase in temperature due to self-heating. The objective of this study was to quantify such self-heating, during fatigue testing, as one of the biases affecting the fatigue life estimation of bituminous materials. A heterogeneous approach, which consists of separating the viscoelastic matrix from the elastic aggregates, has been adopted. According to a complex domain approach, a finite element simulation of a cyclic mechanical loading is proposed by taking into account the dissipated energy, internal thermal evolution, temperature dependence of the matrix stiffness and the heat transfer process. In considering a thermomechanical coupling, the numerical simulation results indicate that dissipated energy in the bituminous matrix is influenced by material heterogeneities. A higher dissipated energy can be observed in thin matrix films, where the strain level exceeds that of thicker films. An estimation of temperature evolution using dissipated energy as a heat source is in a good agreement with experimental results. Local temperature variations are dependent on the local heat source, the thermal properties of each phase and aggregate distribution.
Published: 2016

11. Bulk composition and microstructure dependence of effective thermal conductivity of porous inorganic polymer cements

Author: Mc Bignozzi, Sylvie Rossignol, David S. Smith, Benoît Nait-Ali, Ellie Kamseu, Cristina Leonelli, E. Kamseu, B. Nait-Ali, M.C. Bignozzi, C. Leonelli, S. Rossignol, D.S. Smith, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Università degli Studi di Modena e Reggio Emilia (UNIMORE), Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), and Rossignol, Sylvie
Subjects: Materials Chemistry2506 Metals and Alloys, Materials science, Microstructure-final, 0211 other engineering and technologies, 02 engineering and technology, Matrix (geology), Thermal conductivity, Thermal insulation, Inorganic polymer cements, EFFECTIVE THERMAL CONDUCTIVITY, 021105 building & construction, Homogeneity (physics), Materials Chemistry, Composites, Porosity, Ceramics and Composites, Composite material, Chemical composition, ANALYTICAL MODELS, [CHIM.MATE] Chemical Sciences/Material chemistry, Inorganic polymer, POROUS GEOPOLYMERS, business.industry, POROSITY, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Microstructure, PORE SIZE, 0210 nano-technology, business
Abstract: International audience; Experimental results and theoretical models are used to assess the effective thermal conductivity of porous inorganic polymer cements, often indicated as geopolymers, with porosity between 30 and 70. vol.%. It is shown that the bulk chemical composition affects the microstructure (grains size, pores size, spatial arrangement of pores, homogeneity, micro cracks, bleeding channels) with consequently the heat flow behaviour through the porous matrix. In particular, introduction of controlled fine pores in a homogeneous matrix of inorganic polymer cements results in an increase of pore volume and improvement of the thermal insulation. The variation of the effective thermal conductivity with the total porosity was found to be consistent with analytical models described by Maxwell-Eucken and Landauer.
Published: 2012

12. Microstructural and electrical characterization of bulk YBa2Cu3O7−δ ceramics

Author: David S. Smith, A. Khalfi, Jean Pierre Bonnet, G. Trolliard, M.F. Khalfi, S. Suasmoro, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Université Djilali Liabès [Sidi-Bel-Abbès], Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: Materials science, Magnetic, Current, Extrapolation, Field, Thermodynamics, YBa2Cu3O7−δ Synthesis, 02 engineering and technology, Conductivity, 01 natural sciences, Electrical resistivity and conductivity, 0103 physical sciences, Materials Chemistry, Ceramic, Porous ceramic-limited grain growth, 010302 applied physics, Superconductivity, Process Chemistry and Technology, Metallurgy, Microcracks, [CHIM.MATE]Chemical Sciences/Material chemistry, A. Sintering, 021001 nanoscience & nanotechnology, Microstructure, Grain size, Critical, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, visual_art, Volume fraction, Ceramics and Composites, visual_art.visual_art_medium, Superconductor, 0210 nano-technology
Abstract: The value of critical current density at 77 K in “zero” applied field ( J c ) characterizing the superconducting state for YBa 2 Cu 3 O 7− δ ceramics is closely related to the microstructure. The interrelationships between the microstructural factors such as pore volume fraction, oxygen content, average grain size, are complex. However, these factors also influence the normal state resistivity measured at room temperature ( ρ 300 ). We demonstrate how the current carrying cross section influences Jc and ρ 300 in a similar way. Data, reported for two classes of YBa 2 Cu 3 O 7− δ : small grain porous ceramics and larger-grain denser ceramics, reveal an approximate linear relation between ρ 300 K and J c . Extrapolation of this relation to a fully dense small grain YBa 2 Cu 3 O 7− δ ceramic yields values of ρ 300 = 0.4 mΩ cm and J c = 10 3 A cm −2 .
Published: 2012

13. Physical-chemistry of silica/alkaline silicate interactions during consolidation. Part 1: Effect of cation size

Author: Sylvie Rossignol, Monique Tohoué Tognonvi, Julien Soro, Rossignol, Sylvie, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: Materials science, Potassium, Inorganic chemistry, Hydration shell, Ionic bonding, chemistry.chemical_element, 02 engineering and technology, Ionic bonds, 010402 general chemistry, 01 natural sciences, chemistry.chemical_compound, Alkaline silicate solution, Materials Chemistry, Solubility, Potassium silicate, [CHIM.MATE] Chemical Sciences/Material chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Silicate, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Compressive strength, Solvation shell, chemistry, Agglomerate, Silica sand, Ceramics and Composites, Consolidated materials, 0210 nano-technology
Abstract: International audience; The purpose of this work is to identify the effect of the cation nature on mechanisms of the sand consolidation with alkaline silicate solution at low temperature (70 °C). Three diluted lithium, sodium and potassium silicate solutions with [Si] = 2.8 mol/l were used to agglomerate sand composed of grains which mean diameter is 340 μm. According to the cation, different behaviors were observed in terms of the drying time and the material cohesion. Essentially, the drying time increases with decreasing cation size. In contrast, the compressive strength raises when the cation size increases inducing intra-granular rupture highlighted by SEM observations. This could find an explanation in the cation hydration sphere of cations. The strength of the cation-water electrostatic interaction becomes less important as the size of the cations increase leading to more ionic bonds. Despite their strong consolidation, potassium-based materials have a high solubility in water. This result is consistent with the ionic nature of bonds
Published: 2012

14. Geomaterial foams: role assignment of raw materials in the network formation

Author: Sylvie Rossignol, Agnès Smith, Philippe Michaud, Claire Peyratout, Elodie Prud'Homme, Isabel Sobrados, José Sanz, Emmanuel Joussein, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: Materials science, Silica fume, 02 engineering and technology, Raw material, 010402 general chemistry, 01 natural sciences, Biomaterials, NMR spectroscopy, Materials Chemistry, Organic chemistry, Reactivity (chemistry), Thermal analysis, Infrared spectroscopy, Dissolution, Metakaolin, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Decomposition, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Geopolymer, Chemical engineering, Ceramics and Composites, 0210 nano-technology
Abstract: International audience; The geomaterial foams studied is based on geopolymerization reactions, which is a type of geosynthesis that involves silico-aluminates. Its study during formation has however revealed a different behavior than geopolymer, suggesting the formation of various networks. This work investigates the interaction between initial compounds (metakaolin, silica fume, potassium-based solution) by a kind of mixture decomposition to ultimately understand the formation mechanism of foam. The structural evolution was determined using thermal analysis, FTIR spectroscopy and 27Al and 29Si MAS-NMR measurements. The use of different raw materials in combination with various solutions demonstrates the formation of various species in solution. The reactivity of the solution will then evolve in different ways. The Si/K ratio controlled the type of species created and, particularly, the reactivity in the mixture. From the various reactions of dissolution and polycondensation that were deduced, we could identify the composition of the four networks (K 0.5SiAl 0.75O 6.8H 8.6; K 2Si 2O 5; KAlSi 2O 4,1. 5H 2O; and amorphous silica) constituting the foam
Published: 2011

15. Refinement of digital image correlation technique to investigate the fracture behaviour of refractory materials

Author: Arnaud Germaneau, Pascal Doumalin, Thierry Chotard, Younès Belrhiti, Jean-Christophe Dupré, Marc Huger, Octavian Pop, DERORY, BEATRICE, Axe 4 : céramiques sous contraintes environnementales (SPCTS-AXE4), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Axe 1 : procédés céramiques, Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Institut Pprime (PPRIME), Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM)
Subjects: Digital image correlation, [CHIM.MATE] Chemical Sciences/Material chemistry, Materials science, Composite number, [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, Kinematics, [SPI.MAT] Engineering Sciences [physics]/Materials, 021001 nanoscience & nanotechnology, Microstructure, [SPI.MAT]Engineering Sciences [physics]/Materials, Digital image, Cracking, 020303 mechanical engineering & transports, Discontinuity (geotechnical engineering), Planar, 0203 mechanical engineering, Forensic engineering, Composite material, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract: International audience; Refractory materials exhibit a heterogeneous microstructure consisting in coarse aggregates surrounded by fine grains that form an aggregate/matrix composite. This heterogeneous microstructure often leads to a complex mechanical behaviour during loading. This paper is devoted to the study, thanks to an optical method, Digital Image Correlation (DIC), of the fracture behaviour of two industrial refractory materials in relation with their microstructure resulting from both the chosen constituents and the sintering process. The aim is here, specifically, to highlight and to characterize the evolution of kinematic fields (displacement and strain) observed at the surface of sample during a wedge splitting test typically used to quantify the work of fracture. DIC is indeed a helpful and effective tool, in the topic of experimental mechanics, for the measurement of deformation in a planar sample surface. This non-contact optical method directly provides full-field displacements by comparing the digital images of the sample surface obtained before and during loading. In the present study, DIC has been improved to take into account the occurrence of cracks and performed so as to better identify the early stage of the cracking behaviour. The material transformation, usually assumed homogeneous inside each DIC subset, is thus more complex and a discontinuity of displacement should be taken into account. Then each subset which crosses a crack can be cut in two parts with different kinematics. By this way, it is possible to automatically find the fracture paths and follow the crack geometries (length, opening).
Published: 2015

16. Physical-chemical characterization of Tunisian clays for the synthesis of geopolymers materials

Author: Emmanuel Joussein, Sylvie Rossignol, S. Selmani, A. Driss, Ali Sdiri, Najet Essaidi, Samir Bouaziz, Fabrice Gouny, Laboratoire de Chimie Industrielle, École Nationale d'Ingénieurs de Sfax | National School of Engineers of Sfax (ENIS), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: Palygorskite, Mineralogy, 020101 civil engineering, Geology, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0201 civil engineering, Thermogravimetry, Chemical engineering, Aluminosilicate, medicine, Kaolinite, Mica, Fourier transform infrared spectroscopy, 0210 nano-technology, Clay minerals, Metakaolin, ComputingMilieux_MISCELLANEOUS, Earth-Surface Processes, medicine.drug
Abstract: Natural clay materials from Tunisia were examined as an aluminosilicate source for the synthesis of consolidated materials at low temperatures. Three clay samples were collected from the El Kef, Douiret and Gafsa basins and calcined at different temperatures. All of the samples were characterized using chemical and mineralogical analyses, thermogravimetry, dilatometry, and Fourier transform infrared spectroscopy (FTIR) measurements. The chemical (XRF) and mineralogical analyses (XRD and FTIR) indicated that all of the samples contained various amounts of kaolinite and quartz, followed by calcite, mica, palygorskite and gypsum. Curing produced a binder which did not significantly affect the physic-chemical properties of these clays. The obtained materials heterogeneous did not reach the geopolymerization stage, most likely because of their low kaolinite content. The addition of a suitable aluminosilicate to these clays is therefore recommended to produce homogeneous consolidated geopolymers. The synthesized materials obtained after the addition of metakaolin to the formulation to improve reactivity have interesting properties, thereby providing good potential for Tunisian clays in the synthesis of geopolymers.
Published: 2015

17. Effect of organic modification on the thermal transformations of abentonite during sintering up to 1250°C

Author: Gisèle Laure Lecomte-Nana, J-P Bonnet, F Gridi-Bennadji, Sylvie Rossignol, R Mayet, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Rossignol, Sylvie
Subjects: Materials science, Analytical chemistry, Mineralogy, Sintering, Cordierite, 02 engineering and technology, Crystal structure, engineering.material, 010402 general chemistry, 01 natural sciences, law.invention, Metal, law, General Materials Science, Calcination, Thermal analysis, ComputingMilieux_MISCELLANEOUS, [CHIM.MATE] Chemical Sciences/Material chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Mechanics of Materials, visual_art, X-ray crystallography, Bentonite, engineering, visual_art.visual_art_medium, 0210 nano-technology
Abstract: X-ray diffraction (XRD) and thermal analysis techniques were used to study the thermal transformations of raw (Maghnia bentonite) and modified bentonite (algae extract (ulvans) within clay). XRD data showed that the basal spacing (d 001) was gradually decreased from∼12.80 A (6.90° (2𝜃)) at room temperature to about 9.97 A (8.86° (2𝜃)) and 10.08 A (8.74° (2𝜃)) after calcination at 200, 400 and 600°C for raw and modified bentonites, respectively. Such behaviour was assigned to the loss of physisorbed water molecules (200°C) and to the occurrence of a distorted octahedral metal (complex for modified bentonite) in the clay. Calcinations above 800°C gave rise to a complete distortion of this crystal lattice, leading to the disappearance of d 001 XRD peak due to the dehydroxylation of bentonites. The occurrence of cordierite was enhanced at lower temperature (1100°C instead of 1250°C) in the modified bentonite.
Published: 2015

18. Influence of the ice front velocity and of the composition of suspensions on thermal properties of bentonite materials prepared using freeze–casting process

Author: Arnaud Alzina, Claire Peyratout, Cécile Pagnoux, Benoît Nait-Ali, Anthony De Marcos, Nicolas Tessier-Doyen, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 1 : procédés céramiques (SPCTS-AXE1), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and This work was financed with a grant from the Research Council of the National Engineering College for Industrial Ceramics (ENSCI)
Subjects: Materials science, Porous ceramics, Scanning electron microscope, [CHIM.MATE]Chemical Sciences/Material chemistry, Microstructure, Phyllosilicates, Anisotropic materials, Grain size, Laser flash analysis, Thermal conductivity, 13. Climate action, Specific surface area, Bentonite, Materials Chemistry, Ceramics and Composites, Front velocity, Laser flash technique, Composite material
Abstract: International audience; The influence of (i) the ice front velocity in the freeze–casting process as well as the addition of two binders, (ii) the inorganic synthetic mineral laponite and (iii) the natural organic oligomer chitosan, on the microstructure and on thermal conductivity of bentonite materials prepared using the freeze–casting process were investigated by scanning electron and interferometric microscopies and the laser flash method. Prior to measurements, materials physico-chemical characteristics were determined using specific surface area, grain size and density measurements. Results show that the width of the strongly oriented pores obtained with the freeze–casting process is modified by the presence of binders, and that in turn, the thermal conductivity and anisotropy are also significantly modified.
Published: 2014

19. Oil-in-water Pickering emulsions stabilized by phyllosilicates at high solid content

Author: David Kpogbemabou, Volga Niknam, Claire Carrion, Marguerite Bienia, Anne Aimable, Gisèle Laure Lecomte-Nana, Axe 1 : procédés céramiques (SPCTS-AXE1), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Contrôle de la Réponse Immune B et des Lymphoproliférations (CRIBL), and Université de Limoges (UNILIM)-Génomique, Environnement, Immunité, Santé, Thérapeutique (GEIST FR CNRS 3503)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Coalescence (physics), Chromatography, Materials science, Aqueous two-phase system, Palygorskite, [CHIM.MATE]Chemical Sciences/Material chemistry, engineering.material, Phyllosilicates, Halloysite, Pickering emulsion, [SPI]Engineering Sciences [physics], Colloid and Surface Chemistry, Rheology, Chemical engineering, Pulmonary surfactant, medicine, engineering, [CHIM]Chemical Sciences, Solid content, Stability, medicine.drug
Abstract: International audience; The present study aims at investigating the preparation and characterization of oil-in-water (O/W) Pickering emulsions stabilized using three different phyllosilicates: kaolin, halloysite, and palygorskite, and at high solid content (15 wt.% in the aqueous phase). Stable O/W emulsions could be obtained with no additional surfactant or surface treatment. The maximal oil fraction that could be introduced without phase separation was determined. The resulting oil/water ratios of 0.32, 0.44 and 0.60 were found for kaolin, halloysite and palygorskite, respectively. The O/W character of the three emulsions was confirmed by a simple “droplet test” and by confocal microscopy, which confirmed the positioning of the clay particles at the oil/water interface. These three phyllosilicates led to a limited coalescence mechanism that promoted the long-term stability of the Pickering emulsions. The rheological behavior of these emulsions was studied and showed that halloysite led to a more rigid structure. This trend could be justified by the formation of a strong network of clay particles due to strong surface interactions combined with an elongated particle shape.
Published: 2014

20. Addition of ammonium molybdate in geopolymer

Author: Vidal, Laeticia, Joussein, Emmanuel, Absi, Joseph, Rossignol, S., Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Rossignol, Sylvie
Subjects: [CHIM.MATE] Chemical Sciences/Material chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2014

21. Thermal Conductivity of Very Porous Kaolin-Based Ceramics

Author: Julie Bourret, Claire Peyratout, Aurélie Michot, Arnaud Alzina, Nicolas Tessier-Doyen, David S. Smith, Jérôme Vicente, Fabienne Pennec, Benoît Nait-Ali, Axe 1 : procédés céramiques (SPCTS-AXE1), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Institut universitaire des systèmes thermiques industriels (IUSTI), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Limousin region for financial support, Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010302 applied physics, Materials science, business.industry, Mullite, 02 engineering and technology, Thermal treatment, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Thermal conductivity, Thermal insulation, visual_art, 0103 physical sciences, Volume fraction, Materials Chemistry, Ceramics and Composites, visual_art.visual_art_medium, Kaolinite, Ceramic, Composite material, 0210 nano-technology, business, Porosity
Abstract: International audience; A clay-based material exhibiting high pore volume fraction andlow thermal conductivity suitable for thermal insulation isdescribed. Starting with a commercial clay containing >75% kaolinite,foams were made by mixing in water and methyl celluloseas a surfactant then beating. After drying at 70°C, the pore volumefraction >94% remains almost constant for treatments upto 1150°C. In contrast, the phases constituting the solid skeletonevolve strongly with removal of surfactant, dehydroxylation ofkaolinite, and formation of mullite. The latter leads to greatermechanical strength but also an increase in thermal conductivity.Thermal treatment of the kaolin foam at 1100°C yields a suitablecompromise between low thermal conductivity of 0.054W.(m.K) – 1 at room temperature with a compressive yield stressof 0.04 MPa. The radiation component in the effective thermalconductivity is 50% at 500°C
Published: 2014

22. Importance of metakaolin impurities for geopolymer based synthesis

Author: Sylvie Rossignol, G. Gasgnier, A. Autef, Emmanuel Joussein, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), IMERYS TABLEWARE FRANCE (IMERYS), IMERYS, Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Rossignol, Sylvie
Subjects: [CHIM.MATE] Chemical Sciences/Material chemistry, Materials science, Potassium, Inorganic chemistry, chemistry.chemical_element, Sodium silicate, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Silicate, 0104 chemical sciences, Geopolymer, chemistry.chemical_compound, chemistry, Aluminosilicate, Impurity, Phase (matter), 0210 nano-technology, Metakaolin
Abstract: International audience; Geopolymers are the object of numerous studies because of their low environmental impact. The synthesis of these geomaterials is achieved by the alkaline activation of aluminosilicates. Alkaline activation is typically accomplished by the activation of potassium or sodium silicate. Since these alkaline silicate solutions are relatively expensive. It is imperative to understand all of the phenomena and reactions involved during geopolymer synthesis. We thus attempted to study the role played by siliceous species in the alkaline silicate solutions. During the setting of the materials, the reactive mixture forms at least two phases: (i) a solid phase and (ii) a gelified liquid which recovered it. The quantity of gel varies with the Si/Al, Si/K and Si/H2O molar ratios. Several exchanges take place at the gel-solid interface and involve composition and pH variations. Moreover, the nature and the number of networks depend on the alkaline solution used.
Published: 2014

23. Effect of humidity on the thermal conductivity of porous zirconia ceramics

Author: David S. Smith, B. Nait-Ali, C. Danglade, Krzysztof Haberko, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 1 : procédés céramiques (SPCTS-AXE1), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and AGH University of Science and Technology [Krakow, PL] (AGH UST)
Subjects: 010302 applied physics, Materials science, Humidity, Relative humidity, 02 engineering and technology, Thermal treatment, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Thermal conductivity, 0103 physical sciences, Volume fraction, Materials Chemistry, Ceramics and Composites, Zirconia, Porous materials, Analytical models, Composite material, 0210 nano-technology, Porous medium, Porosity, Water content
Abstract: International audience; This study focuses on the role of the water content on the effective thermal conductivity of porous ceramics placed in different conditions of relative humidity. Fully stabilized zirconia samples with variation in the capacity to take up water were prepared by varying the temperature of the thermal treatment. The pore volume fraction of the dried samples decreases from 56% down to 30%. Thermal conductivity measurements were made on samples placed in a chamber where the relative humidity was fixed between 3% and 99%. For all samples, the experimental values of the effective thermal conductivity increase significantly with the water content. Experimental results agree closely to analytical predictions based on the upper limit of the Hashin and Shtrikman expressions for calculating the thermal conductivity of the pores (constituted by air and water) and Landauer's effective medium expression for calculating the effective thermal conductivity of the material.
Published: 2013

24. Thermal conductivity of porous materials

Author: Kodai Otsu, Arnaud Alzina, Julie Bourret, Hideaki Matsubara, Fabienne Pennec, Benoît Nait-Ali, Nicolas Tessier-Doyen, David S. Smith, Urs T. Gonzenbach, Pierre Elser, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 1 : procédés céramiques (SPCTS-AXE1), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Nagoya Institute of Technology (NIT), Japan Fine Ceramics Center (JFCC), and Collaboration NITECH - Japan
Subjects: 010302 applied physics, Materials science, Mechanical Engineering, Aluminate, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Microstructure, 01 natural sciences, chemistry.chemical_compound, Thermal conductivity, Volume (thermodynamics), chemistry, Mechanics of Materials, Phase (matter), 0103 physical sciences, Volume fraction, General Materials Science, Composite material, 0210 nano-technology, Porosity, Porous medium
Abstract: International audience; Incorporation of porosity into a monolithic material decreases the effective thermal conductivity. Porous ceramics were prepared by different methods to achieve pore volume fractions from 4 to 95%. A toolbox of analytical relations is proposed to describe the effective thermal conductivity as a function of solid phase thermal conductivity, pore thermal conductivity, and pore volume fraction (νp). For νp < 0.65, the Maxwell–Eucken relation for closed porosity and Landauer relation for open porosity give good agreement to experimental data on tin oxide, alumina, and zirconia ceramics. For νp > 0.65, the thermal conductivity of kaolin-based foams and calcium aluminate foams was well described by the Hashin Shtrikman upper bound and Russell’s relation. Finally, numerical simulation on artificially generated microstructures yields accurate predictions of thermal conductivity when fine detail of the spatial distribution of the phases needs to be accounted for, as demonstrated with a bio-aggregate material.
Published: 2013

25. Potassium geopolymer foams made with silica fume pore forming agent for thermal insulation

Author: Joseph Henon, Sylvie Rossignol, Joseph Absi, David S. Smith, Arnaud Alzina, Axe 1 : procédés céramiques (SPCTS-AXE1), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), and Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3)
Subjects: Materials science, Silicon, Silica fume, Scanning electron microscope, chemistry.chemical_element, 02 engineering and technology, Geopolymer, 01 natural sciences, 7. Clean energy, Thermal conductivity, Thermal insulation, Porous material, 0103 physical sciences, General Materials Science, Composite material, Porosity, Microstructure, 010302 applied physics, business.industry, Mechanical Engineering, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Foam, chemistry, Mechanics of Materials, 0210 nano-technology, business
Abstract: International audience; Porous potassium based geopolymers with a mutli-scale porosity were synthesized. Silica fume is introduced as an additive to the geopolymer formulation. The free silicon contained inside this silica fume is oxidized in alkaline solution, releasing molecular hydrogen which generates the porosity. Previous work has shown how the porosity can be controlled with temperature, repeated temperature cycles and the mass introduced. Using this protocol, homogeneous foams were made and then studied with scanning electron microscopy. In particular the foam expansion has been followed with time in relation to the microstructure. The thermal conductivity values of the foams were evaluated using a fluxmeter method. The effective thermal conductivities are comprised between 0.12 and 0.35 W m-1 K-1 for apparent densities ranging from 0.40 to 0.85 g cm-3. The corresponding calculated pore volume fractions are in the range of 65-85%. The interest of this material is that it combines the advantages of low bulk density and insulating properties with the characteristics of a geopolymer skeleton. Literature reports a very good fire and acid/base resistance, a low cost of production and the possibility of recycling industrial waste in the form of silica fume. © 2012 Springer Science+Business Media, LLC.
Published: 2013

26. Mechanical behavior of an assembly of wood-geopolymer-earth bricks

Author: Gouny, Fabrice, Fouchal, Fazia, Pop, Octavian, Maillard, Pascal, Rossignol, Sylvie, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Centre Technique de Matériaux Naturels de Construction (CTMNC), CTMNC, Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Rossignol, Sylvie
Subjects: Pull-out test, Double shear test, Earth, Extruded brick, Geopolymer, Masonry
Abstract: International audience; Timber frame construction with earth brick infill is a sustainable design that is promising in the building construction field. However, cracks form at the interfaces of the bricks and frame with temperature and humidity fluctuations. A geopolymer binder can create stronger bonds between these two materials than traditional mortar, potentially preventing crack formation. This study focuses on the pull-out and shear mechanical behavior of laboratory assemblies of wood, geomaterial binder and two different types of earth brick. The full-field displacements of double-shear test samples were also obtained by digital image correlation (DIC) to better describe and understand the mechanical behavior of the system. The results show that the geopolymer binder provides good adhesion of approximately 1.5 MPa or 2 MPa, depending on the type of brick. Failure localization is also different for each assembly, occurring inside the brick and binder or only inside the binder. This result is confirmed by DIC analysis. The microstructure of the brick has been correlated with the mechanical behavior of the assembly. First results show that the geopolymer binder can be used as a joint in wood and earth masonry. © 2012 Elsevier Ltd. All rights reserved.
Published: 2013

27. Parameters that influence silica dissolution in alkaline media

Author: Emmanuel Joussein, Sylvie Rossignol, A. Autef, G. Gasgnier, Rossignol, Sylvie, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), IMERYS TABLEWARE FRANCE (IMERYS), IMERYS, Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: 010302 applied physics, [CHIM.MATE] Chemical Sciences/Material chemistry, Materials science, Inorganic chemistry, Sodium silicate, [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, chemistry.chemical_compound, chemistry, 0103 physical sciences, 0210 nano-technology, Dissolution, Alkaline activation
Abstract: International audience; Geopolymers have been the object of numerous studies because of their low environmental impact. The synthesis of these geomaterials is achieved by the alkaline activation of aluminosilicates. Alkaline activation is typically accomplished by the activation of potassium silicate or sodium silicate. These alkaline silicate solutions are relatively expensive. We thus attempted to create these solutions by the dissolution of potassium hydroxide and silica in water. This study focuses on the various parameters that can influence the dissolution of silica in basic media (pH>13). The samples used were amorphous silica, quartz sand and quartz ground to five different size distributions. The study of the dissolution of siliceous species was performed mainly by infrared spectroscopy by varying several factors. Stirring and solution volume played no significant role. However, the size distribution and crystallinity of silica were observed to significantly affect the kinetics of dissolution and the quantities of siliceous species in solution, which varied greatly according to the quantity of KOH introduced.
Published: 2013

28. Behavior of metakaolin-based potassium geopolymers in acidic solutions

Author: Emmanuel Joussein, Philippe Michaud, Xiao Xiao Gao, Sylvie Rossignol, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: Materials science, Potassium, 0211 other engineering and technologies, chemistry.chemical_element, Acid resistance, 02 engineering and technology, Geopolymer, Carbonate species, 021105 building & construction, Materials Chemistry, Immersion (virtual reality), Fourier transform infrared spectroscopy, Composite material, Metakaolin, chemistry.chemical_classification, Sample mass, Polymer, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Degradation mechanism, 6. Clean water, Electronic, Optical and Magnetic Materials, Compressive strength, chemistry, Chemical engineering, Ceramics and Composites, 0210 nano-technology, Composition
Abstract: International audience; This work studies the behavior of a metakaolin-based potassium geopolymer immersed in HCl solution (pH = 2). The polymer was attacked in three different ways to determine the effects of the immersion time, successive acid attack and the S/V value (sample mass/volume of solution) on the released elements and on pH. XRD, SEM and compressive strength studies showed that the basic geopolymer network remains intact regardless of the attack method. pH monitoring and FTIR demonstrated the existence of KHCO3 and K2CO3, likely resulting from the excessive KOH after the geopolymer samples react with atmospheric CO2. These basic species were considered the main products of the initial immersion in HCl solutions.
Published: 2013

29. Role of the silica source on the geopolymerization rate: A thermal analysis study

Author: Emmanuel Joussein, G. Gasgnier, A. Autef, Sylvie Rossignol, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), IMERYS TABLEWARE FRANCE (IMERYS), IMERYS, Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Rossignol, Sylvie
Subjects: Condensation polymer, Materials science, 02 engineering and technology, 010402 general chemistry, Geopolymer, 01 natural sciences, chemistry.chemical_compound, Materials Chemistry, Organic chemistry, Thermal analysis, Dissolution, Metakaolin, Amorphous silica, Gel, Porosimetry, Quartz, respiratory system, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Silicate, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Amorphous solid, Chemical engineering, chemistry, Ceramics and Composites, 0210 nano-technology
Abstract: International audience; ncreasing the amount of amorphous silica in a mixture containing silica and quartz favors a polycondensation reaction (i.e., geopolymerization) and improves the mechanical properties of the synthesized materials. The study aimed to investigate the polycondensation reaction during the consolidation step of geopolymer formation and examine the various equilibriums at different temperatures. In total, eleven compositions with various amounts of amorphous silica S (high reactivity) and quartz Q (low reactivity) (from 100%Q to 100%S) were synthesized in basic media with metakaolin. The synthesized samples were characterized by thermal analyses and mercury porosimetry. Correlations between the loss of water and the molar ratio of each composition were investigated. The existence of four reactions during the consolidation process was demonstrated: (i) the reorganization of the species; (ii) the dissolution of the metakaolin; (iii) the formation of oligomers; and (iv) the reaction of polycondensation. Moreover, two types of networks were shown, a silicate solution network for quartz-rich samples and a geopolymeric network for amorphous silica-rich samples. The nature of the primary network and the reactivity of the synthesized sample depend on the reactivity of the silica source used. © 2013 Elsevier B.V.
Published: 2013

30. New mortar for clay masonry structures

Author: Fabrice Gouny, Sylvie Rossignol, Pascal Maillard, Fazia Fouchal, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Centre Technique de Matériaux Naturels de Construction (CTMNC), CTMNC, Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Rossignol, Sylvie
Subjects: [CHIM.MATE] Chemical Sciences/Material chemistry, Digital image correlation, Materials science, business.industry, 0211 other engineering and technologies, General Engineering, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, Masonry, 021001 nanoscience & nanotechnology, Geopolymer, Shear (geology), 021105 building & construction, Shear stress, Infill, Geotechnical engineering, Direct shear test, Composite material, Mortar, 0210 nano-technology, business
Abstract: International audience; Construction system using timber frame with earth brick infill shows the formation of cracks at their interface with the fluctuation of temperature and humidity. Geopolymer binder has been identified to create good adhesion between these two materials. The aim of the study is to characterize the pullout and shear mechanical behavior of laboratory masonry assemblies of wood, geomaterial binder and extruded earth brick. Compression test on the brick were also performed. Full-field deformation of double shear test sample werecarried-out by digital image correlation (DIC) in order to better describe and understand the mechanical behavior. The geopolymer binder show good adhesion properties with mean shear test results around 1.5 MPa and pullout test result around 0.82MPa. © (2013) Trans Tech Publications, Switzerland.
Published: 2013

31. Influence of raw materials and potassium and silicon concentrations on the formation of a zeolite phase in a geopolymer network during thermal treatmen

Author: Sylvie Rossignol, Philippe Michaud, Emmanuel Joussein, Elodie Prud'Homme, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Rossignol, Sylvie
Subjects: Materials science, Silica fume, Silicon, Potassium, Mineralogy, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, In situ geopolymer foam, law.invention, chemistry.chemical_compound, law, Phase (matter), Materials Chemistry, Thermal analysis, Crystallization, [CHIM.MATE] Chemical Sciences/Material chemistry, Zeolite, Hydrated silica, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Geopolymer, FTIR spectroscopy, chemistry, Chemical engineering, Ceramics and Composites, Silica reactivity, 0210 nano-technology
Abstract: International audience; The development of porous materials based on geopolymers allows the benefits of eco-consumption, good insulating properties and good mechanical properties to be combined. For geopolymers to be useful, the development of an understanding of their properties under various conditions is important. Attention was given to the structural evolution of porous materials with heating. The structural evolutions were investigated using thermal analysis and infrared spectroscopy. The formation of a crystalline phase was observed and identified as a zeolite. To elucidate the roles played by the raw materials, silicon concentration and potassium concentration on the formation of the crystalline phase, three parameters in the foam synthesis process were modified. The influence of silica fume and metakaolin on the appearance of the crystalline phase was examined through the reactivity of the raw materials in contact with a potassium solution. Different behaviors directly linked to the network composition were observed. Silica-fume-based samples showed phase crystallization and dehydroxylation due to the large concentration of silicon, which likely led to the formation of hydrated silica species. The formation of the zeolite-phase network upon the application of heat depended only on the silica dissolution and was linked to the composition of silica in terms of the silicon species and grain size. Studying the crystalline phase formation by variation of the amount of potassium allowed the determination of a maximum silicon concentration and a minimum potassium concentration. The formation of the zeolite phase occurred at a potassium concentration greater than 3.5 mol*L - 1 and a silicon concentration lower than 16.5 mol*L - 1, which confirmed the presence of F-zeolites
Published: 2012

32. Physico-chemistry of silica / Na silicate interactions during consolidation. Part 2: Effect of pH

Author: Monique Tohoué Tognonvi, Julien Soro, Jean-Louis Gelet, Sylvie Rossignol, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), MERSEN, Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Rossignol, Sylvie
Subjects: Sodium silicate solution, Sodium, Inorganic chemistry, chemistry.chemical_element, Sodium silicate, Mechanical properties, 02 engineering and technology, 010502 geochemistry & geophysics, 01 natural sciences, Chemical reaction, chemistry.chemical_compound, Materials Chemistry, Dissolution, 0105 earth and related environmental sciences, Basic medium, [CHIM.MATE] Chemical Sciences/Material chemistry, Chemistry, Depolymerization, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Silicate, Electronic, Optical and Magnetic Materials, Distilled water, Ceramics and Composites, Surface modification, 0210 nano-technology, Consolidated materials
Abstract: International audience; This work aims to study the effect of the pH of a sodium silicate solution on the consolidation of silica-based aggregates at low temperature (70 °C). A diluted solution obtained by adding 50 wt% of distilled water into a concentrated commercial solution was used as starting solution. Solutions with an increasing pH values were prepared by alkalinizing the diluted solution with solid NaOH. This leads to the depolymerization of silicate species present in solution. Consolidated materials were obtained by impregnating silica sand with the solution. In order to increase the surface reactivity, the sand was also functionalized by a prior basic attack. Results reveal that the increase in the pH value or the functionalization of the sand surface leads to improve mechanical properties of materials suggesting chemical reactions between the components confirmed by FTIR experiments. Actually, the ν asSi-O-Si broad band with a sharp peak located around 1015 cm -1, shifts firstly to lower and then to higher wavenumber characteristic of dissolution / precipitation reactions. Moreover, the enhancement of the pH value induces intra-granular break characterized by SEM observations confirming the best consolidation. However, these samples are more soluble in water related to the excess in sodium that induces more ionic bonds.
Published: 2012

33. Role of dispersant and humidity on the setting of millimetric films of aluminous cement prepared by tape casting

Author: Jean-Pierre Bonnet, L. Nibou, Thierry Chartier, Agnès Smith, Y. Abouliatim, Y. El Hafiane, Ecole Nationale des Sciences Appliquées [Safi] (ENSA), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 1 : procédés céramiques, Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Axe 1 : procédés céramiques (SPCTS-AXE1), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: Materials science, Dispersant, 02 engineering and technology, Tape casting, Rheological behaviour, 01 natural sciences, Acetic acid, chemistry.chemical_compound, 0103 physical sciences, Materials Chemistry, Relative humidity, Composite material, Films, 010302 applied physics, Cement, Humidity, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, chemistry, Ceramics and Composites, Slurry, 0210 nano-technology, Dispersion (chemistry), Aluminous cement
Abstract: International audience; An aluminous cement (Secar 71 from Lafarge) has been used for preparing millimetre thick films by tape casting. Slurry preparation is described. The effect of several dispersants has been studied. The optimum dispersion, associated with the minimum viscosity, is obtained with minimal amounts of dispersant in the case of acetic and propionic acids. Indeed, the corresponding quantities of dispersant are less than 0.5% by weight relative to cement. In addition to its dispersive role, acetic acid plays a role in the setting. It has a retarding effect below 1% by weight relative to the mass of cement and from this amount, it plays an accelerating role on setting. Tapes prepared with cement, water, acetic acid, PEG 300 have been left to set in different environments at 20 ◦C (50% or 95% relative humidity, water). The formation of aluminous calcium hydrates is most important when setting is done in water. Lastly, the advantage of setting in water is also discussed with respect to the elimination of the different organic products that have been used for tape casting.
Published: 2012

34. Thermal conductivity of geomaterial foams based on silica fume

Author: Elodie Prud'Homme, Julie Bourret, David S. Smith, Sylvie Rossignol, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Axe 1 : procédés céramiques (SPCTS-AXE1)
Subjects: Chemical compositions, Materials science, Silica fume, Steady-state heat flow, Sodium silicate, 02 engineering and technology, Thermal treatment, 01 natural sciences, chemistry.chemical_compound, Thermal conductivity, 0103 physical sciences, General Materials Science, Composite material, Porosity, Chemical composition, 010302 applied physics, Mechanical Engineering, Sodium hydroxides, Geomaterials, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Thermal conductivity measurements, chemistry, Mechanics of Materials, Sodium hydroxide, Laser flash techniques, Reference material, 0210 nano-technology, Porous medium
Abstract: Porous materials have been prepared from a solution containing sodium silicate and sodium hydroxide with the addition of silica fume. Kaolin and diatomite were also tested as additives to the initial formulation. This method yields consolidated geomaterial foams without requiring thermal treatment above $$50\,{}^{\circ}\hbox{C}$$ . The influence of chemical composition on the thermal conductivity was studied. The choice of raw materials was found to play an important role. The accuracy of thermal conductivity measurements was evaluated by comparing the steady state heat flow method with the laser flash technique for five different reference materials giving values within 6%. Using the steady state heat flow method, a value of $$0.12 \pm 0.01\,{\rm W}\,{\rm m}^{-1}\,{\rm K}^{-1}$$ was then obtained for consolidated foams, made with kaolin as the precursor, containing approximately 70% of porosity.
Published: 2012

35. A simple route for the preparation of P-modified TiO 2: Effect of phosphorus on thermal stability and photocatalytic activity

Author: Kais Elghniji, Sylvie Rossignol, Mohamed Ksibi, Julien Soro, Département de Génie Électrique de Sfax [ENIS] (CEM Lab - ENIS), École Nationale d'Ingénieurs de Sfax | National School of Engineers of Sfax (ENIS), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Laboratoire des Systèmes Electromécaniques (LASEM), and Rossignol, Sylvie
Subjects: Anatase, TiP 2O 7, General Chemical Engineering, Inorganic chemistry, chemistry.chemical_element, Particle growth, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, law.invention, chemistry.chemical_compound, law, Calcination, Thermal stability, [CHIM.MATE] Chemical Sciences/Material chemistry, Chemistry, Phosphorus, Phosphorus content, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Phosphate, 0104 chemical sciences, Photocatalysis, Crystallite, 0210 nano-technology, TiO 2, Nuclear chemistry, BET theory
Abstract: Phosphorus-modified dioxide nanoparticles were prepared by sol–gel method. The effect of phosphorus precursor and calcination temperatures on phase transformation, grain growth and surface area were investigated using various spectroscopic and basic techniques (ICP-AES, XRD, BET, 31 P MAS NMR, FT-IR, and UV–vis methods). It was found that the phosphorus existed as amorphous titanium phosphate in TiO 2 framework after calcination at temperature of 500–700 °C. As results, slows down the particle growth of anatase and increases the anatase-to-rutile phase transformation. The average crystallite size of P-modified TiO 2 increased dramatically from 8 to 59 nm when the temperature increased from 500 to 900 °C. This change was associated with the formation of pyrophosphate TiP 2 O 7 species through condensation of the concentrated phosphate species. The BET surface area of modified samples was 3.4-fold higher than that of unmodified TiO 2 and was 70% higher than that of commercial Degussa P-25. The photocatalytic activity of P-modified TiO 2 was 1.5-fold higher than that of commercial Degussa P-25 and was 49% higher than that of unmodified TiO 2 under UV irradiation. Phytotoxicity was assessed before and after irradiation against seed germination of tomato ( Lycopersicon esculentum ).
Published: 2012

36. Alpha self-irradiation effect on the local structure of the local structure of the U0.85Am0.15O2+x solid solution

Author: Prieur, D., Martin, P.M., Lebreton, F., Delahaye, T., Jankowiak, Aurélien, Laval, Jean-Paul, Scheinost, A. C., Dehaudt, P., Blanchart, Philippe, CEA Marcoule, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CEA, Laboratoire d'Etude du Comportement Mécanique des Matériaux (LC2M), Service des Recherches Métallurgiques Appliquées (SRMA), Département des Matériaux pour le Nucléaire (DMN), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Département des Matériaux pour le Nucléaire (DMN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Institute of Resource Ecology [Dresden], Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), CEA-Direction de l'Energie Nucléaire (CEA-DEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction de l'Energie Nucléaire (CEA-DEN), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Institute of Resource Ecology, and Institute of Radiochemistry
Subjects: Americium, XAS, Uranium, Self-irradiation, Transmutation, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2012

37. Cohésion à l’interface matrice minérale/fibres cellulosiques : traitements chimiques des fibres et caractérisation

Author: Claire Peyratout, Ali Rachini, Cécile Pagnoux, Agnès Smith, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 1 : procédés céramiques (SPCTS-AXE1), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: sodium hydroxide, organosilanes grafting, TGA/DTA, General Materials Science, 02 engineering and technology, Hemp fibers, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 0210 nano-technology, 01 natural sciences, 0104 chemical sciences, ATR-FTIR
Abstract: L’utilisation des fibres cellulosiques comme renfort dans une matrice minerale (dans notre cas a base d’un melange de phyllosilicates et d’un liant hydraulique) presente deux inconvenients majeurs qui sont lies au caractere hydrophile des fibres ainsi qu’a leur sensibilite thermique. Afin de modifier les proprietes de surface des fibres, des traitements chimiques, mecaniques et thermiques prealables a l’incorporation des fibres dans le materiau composite sont generalement appliques. En particulier, des traitements chimiques utilisant des solutions de soude (NaOH) et le greffage de molecules organiques augmentent la cohesion a l’interface fibre/matrice et permettent d’ameliorer les proprietes mecaniques du materiau composite final. Nos travaux se concentrent sur la modification de la surface de fibres de chanvre par traitements chimiques (traitement avec NaOH, greffage d’organosilanes a differentes compositions chimiques et a differentes concentrations) ainsi que la caracterisation des proprietes thermiques et surfaciques par differentes techniques de caracterisation fonctionnelles et structurales (ATD/ATG, IRTF-ATR, BET et MEB).
Published: 2012

38. Reply to the J. Provis and S.A. Bernal comment about the article 'structural characterization of geomaterial foams. Thermal behavior' published in J. Non-Cryst. Solids, 2011

Author: Philippe Michaud, Isabel Sobrados, Sylvie Rossignol, Emmanuel Joussein, Elodie Prud'Homme, Jesús Sanz, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Instituto de Ciencia de Materiales de Aragón [Saragoza, España] (ICMA-CSIC), University of Zaragoza - Universidad de Zaragoza [Zaragoza], Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Rossignol, Sylvie
Subjects: Materials science, Mineralogy, Thermodynamics, Infrared spectroscopy, 02 engineering and technology, 010402 general chemistry, Geopolymer, 01 natural sciences, Nuclear magnetic resonance, Physical chemical, Thermal, Materials Chemistry, Aluminosilicate gel, [CHIM.MATE] Chemical Sciences/Material chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Characterization (materials science), NMR spectra database, 13. Climate action, Thermogravimetry, Ceramics and Composites, 0210 nano-technology
Abstract: International audience; In this paper, we discuss the alternative interpretation of NMR spectra from (i) “Structural characterization of geomaterial foams—Thermal behavior” by Prud'homme et al. published in Journal of Non-Crystalline Solid, 2011, and from (ii) the reply proposed by J. Provis and S.A. Bernal in this journal. In this contribution, other alternatives for the NMR bands assignment are discussed and compared with infrared spectroscopy and thermo-gravimetric results since closed relationship between NMR-IR-TG is effective. In agreement with these authors, the analysis of prepared foams requires additional work addressed to detect the presence of two phases with different tetrahedral condensation. Relative arrangement of these two phases could affect in a significant way the physical chemical properties of prepared foams.
Published: 2012

39. Rheological properties of montmorillonitic clay suspensions: Effect of firing and interlayer cations

Author: Jean-Pierre Bonnet, Gisèle Laure Lecomte-Nana, Sylvie Rossignol, Fayza Gridi-Bennadji, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Rossignol, Sylvie
Subjects: Calcination temperature, Materials science, Mineralogy, 02 engineering and technology, 01 natural sciences, law.invention, chemistry.chemical_compound, Rheology, law, Interlayer cations, Materials Chemistry, Calcination, Surface interactions, Solid content, [CHIM.MATE] Chemical Sciences/Material chemistry, Aqueous solution, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 010406 physical chemistry, 0104 chemical sciences, Montmorillonite, Chemical engineering, chemistry, Ceramics and Composites, 0210 nano-technology, Montmorillonites suspensions
Abstract: International audience; The effect of a prior firing of three montmorillonite clays, exhibiting different nature of interlayer cations, on the rheological behaviour of related aqueous suspensions (5 and 10. mass% of solid content) was examined. Calcinations were performed at 150 °C, 250 °C, 300 °C or 450 °C for 30 min. The rheological properties were characterized at 25 °C in the flow mode using the Herschel-Bulkley model. The alkaline interlayer cation (Na) tended to increase the yield stress of montmorillonite suspensions in comparison with earth-alkaline ones (Ca, Mg). As expected, increasing solid content led to increasing yield stress. For calcinations until 200 °C, the relevant suspensions exhibited an increasing yield stress due to a gel-like behaviour in relation with a card-house-like structure. Furthermore, calcination above 300 °C favoured the decrease of the corresponding yield stress. This behaviour seemed to be related to the modification of the surface properties of the clay platelets, more precisely to the beginning of clay dehydroxylation.
Published: 2012

40. A geopolymer mortar for wood and earth structures

Author: Sylvie Rossignol, Fazia Fouchal, Fabrice Gouny, Pascal Maillard, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Centre Technique de Matériaux Naturels de Construction (CTMNC), CTMNC, Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Rossignol, Sylvie
Subjects: Materials science, 0211 other engineering and technologies, 02 engineering and technology, Geopolymer, 021105 building & construction, Shear stress, Double shear test, General Materials Science, Composite material, Thermal analysis, Infrared spectroscopy, Metakaolin, Civil and Structural Engineering, [CHIM.MATE] Chemical Sciences/Material chemistry, Building and Construction, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Mortar, Compressive strength, Shear (geology), Extruded earth brick, 0210 nano-technology, Geopolymer mortar
Abstract: International audience; In building construction, because of the hygroscopic nature of wood and earth brick and the low adhesion between these materials, cracks are formed at their interface when they are assembled. Geopolymer binder has been show to create strong bonds between wood and earth brick. Assemblies of wood and extruded earth brick with geopolymer binder were manufacture and tested. Double shear tests at two scales were carried out that provided evidence of good adhesion and information about the influence of the type of brick on shear behavior. The workability of the binder was improved by adding siliceous aggregates. The mortar obtained has an improved compressive strength, ranging from 3 to 8 MPa, depending on the aggregate size. FTIR measurements and thermal analysis were performed to determine the reaction mechanism
Published: 2012

41. Role of the silica source on the geopolymerization rate ALL or

Author: Autef, Alexandre, Joussein, Emmanuel, Gasgnier, G., Rossignol, Sylvie, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), IMERYS TABLEWARE FRANCE (IMERYS), IMERYS, Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), and Rossignol, Sylvie
Subjects: [CHIM.MATE] Chemical Sciences/Material chemistry, Amorphous silica, FTIR spectroscopy, Sand, Thermal analysis, [CHIM.MATE]Chemical Sciences/Material chemistry, Geopolymer
Abstract: International audience; The synthesis of geopolymer-silica composites was achieved at room temperature to determine the role of the silica source (quartz or amorphous silica) on the polycondensation rate and the mechanical properties of synthesized materials. Then, samples with a composition range from 100% quartz to 100% amorphous silica were formed, compared and characterized by XRD, infrared spectroscopy, thermal analysis, SEM, and compression tests. The results give evidence that the increase of amorphous silica in the mixture favors the polycondensation reaction (i.e., "geopolymerization") to form consolidated materials whereas quartz led to heterogeneous materials without cohesion. These facts are explained by the modification of the Si/Al ratio in the geopolymer matrix due to the increase of quartz in the mixture
Published: 2012

42. Characterization of the anisotropic grain coarsening in aluminium titanate ceramic

Author: Gallet-Doncieux, A., Michaud, Philippe, Huger, Marc, chotard, thierry, Ishizawa, N., Ota, T., Svenbro, Anna, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Axe 1 : procédés céramiques, Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Axe 1 : procédés céramiques (SPCTS-AXE1), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM), Department of Environmental and Materials Engineering, Nagoya Institute, Ceramics Research Laboratory, and Nagoya Institute of Technology
Subjects: [SPI]Engineering Sciences [physics], [SPI] Engineering Sciences [physics], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2011

43. The materials saga: sintering

Author: Bernache-Assollant , Didier, Bonnet , Jean-Pierre, Carry , C., Chaput. , C., Chartier , Thierry, Chermant , J.-L., Durand , B., Garrault , S., Herlin , N., Lamerant , J.-M., Leconte , Y., Le Gallet , S., Leriche , A., Niepce , J.-C., Poirier , J., Rebillat , F., Valdivieso , F., Science des Procédés Céramiques et de Traitements de Surface ( SPCTS ), Université de Limoges ( UNILIM ) -Ecole Nationale Supérieure de Céramique Industrielle ( ENSCI ) -Institut des Procédés Appliqués aux Matériaux ( IPAM ), Université de Limoges ( UNILIM ) -Université de Limoges ( UNILIM ) -Institut de Chimie du CNRS ( INC ) -Centre National de la Recherche Scientifique ( CNRS ), École des Mines de Saint-Étienne ( Mines Saint-Étienne MSE ), Institut Mines-Télécom [Paris], Centre Ingénierie et Santé ( CIS-ENSMSE ), Institut Mines-Télécom [Paris]-Institut Mines-Télécom [Paris], Groupe d'Etudes des Matériaux Hétérogènes ( GEMH ), Université de Limoges ( UNILIM ) -Institut des Procédés Appliqués aux Matériaux ( IPAM ), Université de Limoges ( UNILIM ) -Université de Limoges ( UNILIM ), Science et Ingénierie des Matériaux et Procédés ( SIMaP ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut polytechnique de Grenoble - Grenoble Institute of Technology ( Grenoble INP ) -Institut National Polytechnique de Grenoble ( INPG ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Axe 1 : procédés céramiques, Université de Limoges ( UNILIM ) -Université de Limoges ( UNILIM ) -Institut de Chimie du CNRS ( INC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Limoges ( UNILIM ) -Ecole Nationale Supérieure de Céramique Industrielle ( ENSCI ) -Institut des Procédés Appliqués aux Matériaux ( IPAM ), Laboratoire Francis PERRIN ( LFP - URA 2453 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Centre National de la Recherche Scientifique ( CNRS ), Service des Photons, Atomes et Molécules ( SPAM ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), Laboratoire des Matériaux Avancés Céramiques, Université de Valenciennes et du Hainaut-Cambresis ( UVHC ), Laboratoire de Recherche sur la Réactivité des Solides ( LRRS ), Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Mécanique des Systèmes et des Procédés ( LMSP ), Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire des Composites Thermostructuraux ( LCTS ), Université Sciences et Technologies - Bordeaux 1-Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Snecma-SAFRAN group-Centre National de la Recherche Scientifique ( CNRS ), LPMG - Equipe PROCESS, Département Procédés et évolution des systèmes avec solides ( ProcESS-ENSMSE ), Institut Mines-Télécom [Paris]-Institut Mines-Télécom [Paris]-SPIN, Laboratoire des Procédés en Milieux Granulaires ( LPMG-EMSE ), Institut Mines-Télécom [Paris]-Institut Mines-Télécom [Paris]-Centre National de la Recherche Scientifique ( CNRS ), Centre Science des Matériaux et des Structures ( SMS-ENSMSE ), Département Mécanique et Procédés d'Elaboration ( MPE-ENSMSE ), Institut Mines-Télécom [Paris]-Institut Mines-Télécom [Paris]-SMS, Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT), Centre Ingénierie et Santé (CIS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Science et Ingénierie des Matériaux et Procédés (SIMaP), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Institut National Polytechnique de Grenoble (INPG), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Laboratoire Francis PERRIN (LFP - URA 2453), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Service des Photons, Atomes et Molécules (SPAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire des Matériaux Céramiques et Procédés Associés - EA 2443 (LMCPA), Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France), Laboratoire de Recherche sur la Réactivité des Solides (LRRS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mécanique des Systèmes et des Procédés (LMSP), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Composites Thermostructuraux (LCTS), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Snecma-SAFRAN group-Centre National de la Recherche Scientifique (CNRS), Département Procédés et évolution des systèmes avec solides (ProcESS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SPIN, Laboratoire des Procédés en Milieux Granulaires (LPMG-EMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Centre Science des Matériaux et des Structures (SMS-ENSMSE), Département Mécanique et Procédés d'Elaboration (MPE-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SMS, Centre National de la Recherche Scientifique (CNRS)-Snecma-SAFRAN group-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National Polytechnique de Grenoble (INPG)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Valenciennes et du Hainaut-Cambrésis (UVHC)
Subjects: [ SPI.MAT ] Engineering Sciences [physics]/Materials, ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract: International audience; In ICV no 1010, we inaugurated our materials saga with the classification and shaping of ceramics. This second and short chapter deals with sintering and its different forms: non reactive or reactive sintering, natural or pressure sintering as well as two essential parameters: density and porosity.
Published: 2007

44. Dossier matières premières

Author: Bernache-Assollant, Didier, Bonnet, Jean-Pierre, Carry, C., Chaput., C., Chartier, Thierry, Chermant, J.-L., Durand, B., Garrault, S., Herlin, N., Lamerant, J.-M., Leconte, Y., Le Gallet, S., Leriche, Anne, Niepce, J.-C., Poirier, J., Rebillat, F., Valdivieso, F., Stagiaire, Sms, Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT), Centre Ingénierie et Santé (CIS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Laboratoire d'Etudes Aérodynamiques (LEA), Centre National de la Recherche Scientifique (CNRS)-ENSMA-Université de Poitiers, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Science et Ingénierie des Matériaux et Procédés (SIMaP), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Institut National Polytechnique de Grenoble (INPG), Axe 1 : procédés céramiques, Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Laboratoire Francis PERRIN (LFP - URA 2453), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Matériaux Céramiques et Procédés Associés - EA 2443 (LMCPA), Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France), Laboratoire de Recherche sur la Réactivité des Solides (LRRS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mécanique des Systèmes et des Procédés (LMSP), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Composites Thermostructuraux (LCTS), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Snecma-SAFRAN group-Centre National de la Recherche Scientifique (CNRS), LPMG - Equipe PROCESS, Département Procédés et évolution des systèmes avec solides (ProcESS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SPIN, Laboratoire des Procédés en Milieux Granulaires (LPMG-EMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Centre Science des Matériaux et des Structures (SMS-ENSMSE), Département Mécanique et Procédés d'Elaboration (MPE-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SMS, Centre National de la Recherche Scientifique (CNRS)-Snecma-SAFRAN group-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Science des Procédés Céramiques et de Traitements de Surface ( SPCTS ), Université de Limoges ( UNILIM ) -Ecole Nationale Supérieure de Céramique Industrielle ( ENSCI ) -Institut des Procédés Appliqués aux Matériaux ( IPAM ), Université de Limoges ( UNILIM ) -Université de Limoges ( UNILIM ) -Institut de Chimie du CNRS ( INC ) -Centre National de la Recherche Scientifique ( CNRS ), École des Mines de Saint-Étienne ( Mines Saint-Étienne MSE ), Institut Mines-Télécom [Paris], Centre Ingénierie et Santé ( CIS-ENSMSE ), Institut Mines-Télécom [Paris]-Institut Mines-Télécom [Paris], Laboratoire d'Etudes Aérodynamiques ( LEA ), Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique ( CNRS ), Groupe d'Etudes des Matériaux Hétérogènes ( GEMH ), Université de Limoges ( UNILIM ) -Institut des Procédés Appliqués aux Matériaux ( IPAM ), Université de Limoges ( UNILIM ) -Université de Limoges ( UNILIM ), Science et Ingénierie des Matériaux et Procédés ( SIMaP ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut polytechnique de Grenoble - Grenoble Institute of Technology ( Grenoble INP ) -Institut National Polytechnique de Grenoble ( INPG ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Université de Limoges ( UNILIM ) -Université de Limoges ( UNILIM ) -Institut de Chimie du CNRS ( INC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Limoges ( UNILIM ) -Ecole Nationale Supérieure de Céramique Industrielle ( ENSCI ) -Institut des Procédés Appliqués aux Matériaux ( IPAM ), Laboratoire Francis PERRIN ( LFP - URA 2453 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire des Matériaux Avancés Céramiques, Université de Valenciennes et du Hainaut-Cambresis ( UVHC ), Laboratoire de Recherche sur la Réactivité des Solides ( LRRS ), Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Mécanique des Systèmes et des Procédés ( LMSP ), Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire des Composites Thermostructuraux ( LCTS ), Université Sciences et Technologies - Bordeaux 1-Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Snecma-SAFRAN group-Centre National de la Recherche Scientifique ( CNRS ), Département Procédés et évolution des systèmes avec solides ( ProcESS-ENSMSE ), Institut Mines-Télécom [Paris]-Institut Mines-Télécom [Paris]-SPIN, Laboratoire des Procédés en Milieux Granulaires ( LPMG-EMSE ), Institut Mines-Télécom [Paris]-Institut Mines-Télécom [Paris]-Centre National de la Recherche Scientifique ( CNRS ), Centre Science des Matériaux et des Structures ( SMS-ENSMSE ), Département Mécanique et Procédés d'Elaboration ( MPE-ENSMSE ), Institut Mines-Télécom [Paris]-Institut Mines-Télécom [Paris]-SMS, Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National Polytechnique de Grenoble (INPG)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Valenciennes et du Hainaut-Cambrésis (UVHC)
Subjects: [ SPI.MAT ] Engineering Sciences [physics]/Materials, [SPI.MAT] Engineering Sciences [physics]/Materials, ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract: International audience
Published: 2007

45. Incorporation of Wooden Furniture Wastes in Fired Clay Bricks for Improved Thermal Insulation: A Feasability Study

Author: A. Lacanilao, M. Fassier, Nicolas Tessier-Doyen, Agnès Smith, V. Quint, David S. Smith, C. Peyratout, H. Abjaghou, M. A. Bruneaux, J. Bourret, IRCER - Axe 1 : procédés céramiques (IRCER-AXE1), Institut de Recherche sur les CERamiques (IRCER), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)
Subjects: 0106 biological sciences, Brick, Environmental Engineering, Materials science, Renewable Energy, Sustainability and the Environment, business.industry, 020209 energy, Metallurgy, [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, Conductivity, 01 natural sciences, Bulk density, [SPI.MAT]Engineering Sciences [physics]/Materials, Thermal conductivity, Thermal insulation, 010608 biotechnology, Volume fraction, 0202 electrical engineering, electronic engineering, information engineering, Extrusion, Porosity, business, Waste Management and Disposal, ComputingMilieux_MISCELLANEOUS
Abstract: The main objective of this study is to improve thermal insulation of fired clay bricks through addition of wooden furniture waste. The effect of the nature and the amount (5 or 10 wt%) of wooden furniture waste on the properties of the final porous fired brick prepared by extrusion was assessed though measurements of mass loss, drying and sintering shrinkage, porosity, bulk density and thermal conductivity. Results showed that incorporation of wooden furniture waste into the clay mixture yielded increase of porosity after firing and hence decrease of thermal conductivity. For example, addition of 10 wt% wood waste yielded a pore volume fraction of 47% with a conductivity of 0.42 W m−1 K−1. Moreover, due to orientation of the clay platelets, the anisotropy in thermal conductivity was significant, ranging from a ratio of 1.1–1.5.
Published: 2020

46. Irradiation externe aux ions lourds de céramiques et vitrocéramiques d'apatite silicatée au néodyme

Author: J.-L. Dussossoy, Daniel Caurant, Pascal Loiseau, Clara Grygiel, S. Peuget, Nolwenn Chouard, Odile Majérus, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Laboratoire de Chimie Appliquée de l'État Solide (LCAES), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie et de physique des milieux condensés (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Matériaux et Procédés Actifs (LMPA), Département de recherche sur les technologies pour l'enrichissement, le démantèlement et les déchets (DE2D), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), Service d'Etudes du Comportement des Matériaux de Conditionnement (SECM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Département de recherche sur les Procédés et Matériaux pour les Environnements complexes (DPME), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche de Chimie Paris (IRCP), Ecole Nationale Supérieure de Chimie de Paris- Chimie ParisTech-PSL (ENSCP)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), and Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Nuclear and High Energy Physics, Materials science, Ion beam, Analytical chemistry, 02 engineering and technology, 01 natural sciences, Apatite, 010305 fluids & plasmas, law.invention, Ion, chemistry.chemical_compound, symbols.namesake, Swift heavy ion, law, 0103 physical sciences, [CHIM]Chemical Sciences, General Materials Science, Irradiation, ComputingMilieux_MISCELLANEOUS, Glass-ceramic, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Silicate, Nuclear Energy and Engineering, chemistry, visual_art, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], visual_art.visual_art_medium, symbols, 0210 nano-technology, Raman spectroscopy
Abstract: This work aims at comparing the damage induced in the Nd silicate apatite ceramic (Ca2Nd8(SiO4)6O2) by medium energy (ME) and swift heavy ion (SHI) irradiations to evaluate the effects of nuclear collisions and intense electronic excitations for ME ions and SHI ions respectively. The macroscopic induced changes were studied as a function of the fluence by swelling and hardness measurements, whereas structural modifications were followed by X-ray diffraction, Raman spectroscopy and grazing incidence EXAFS (Nd L3-edge). At ME (1.9–6.75 MeV Au ions), radiation-induced amorphization occurred above 6.22 × 1013 Au/cm2 associated with a volume expansion of about 8% and a drop of 37% in hardness. At SHI (90 MeV Xe ions or 35 MeV Ar ions), similar macroscopic and structural changes were observed. The electronic stopping power threshold of Nd silicate apatite for amorphization was assessed at about Se = 5 keV/nm. As apatite crystals containing actinides could be present in rare-earths rich nuclear glasses, SHI irradiation with Xe (995 MeV) ions was also used to damage the Nd silicate apatite crystals dispersed in a soda-lime aluminoborosilicate simplified nuclear glass over a depth of about 60 μm, to evaluate the possible formation of cracks in the residual glass due to crystals swelling. In spite of apatite crystals amorphization under SHI irradiation in the glass-ceramics, no cracking was observed in the glassy phase even close to the biggest crystals which could be explained by strain relaxation in the glass due to plastic deformation (creep) induced by SHI ion beam.
Published: 2019

47. Modelling of asphalt mixes based on X-ray computed tomography and random heterogeneous generation

Author: Yassine El Haloui, Fatima Allou, Joseph Absi, Fabien Courreges, Mohamed El Omari, Fateh Fakhari Tehrani, Christophe Petit, Université Cadi Ayyad [Marrakech] (UCA), IRCER - Axe 2 : procédés plasmas et lasers (IRCER-AXE2), Institut de Recherche sur les CERamiques (IRCER), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Systèmes et Réseaux Intelligents (XLIM-SRI), XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Automatique de l'Environnement et Procédés de Transferts (LAEPT), Faculté des Sciences Semlalia Marrakech, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)
Subjects: 050210 logistics & transportation, Materials science, 05 social sciences, Composite number, 0211 other engineering and technologies, [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, Finite element method, [SPI.MAT]Engineering Sciences [physics]/Materials, Asphalt pavement, Mechanics of Materials, Asphalt, X ray computed, 021105 building & construction, 0502 economics and business, Dynamic modulus, Tomography, Composite material, Mortar, ComputingMilieux_MISCELLANEOUS, Civil and Structural Engineering
Abstract: This paper presents numerical investigations into the mechanical behaviour of hot mix asphalt (HMA) through the use of finite element modelling simulations. HMA is a well-known composite medium con...
Published: 2018

48. Modélisation thermique dynamique d’un amphithéâtre à l’aide d’un réseau de capteurs sans fil : vers un démonstrateur d’outil de diagnostic énergétique dans un bâtiment public

Author: Itoua Engoti, Frank, Angellier, Nicolas, Ulmet, Laurent, Quéré, Raymond, Lalande, Michèle, Dubois, Frédéric, Systèmes RF (XLIM-SRF), XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Laboratoire de Génie Civil, Diagnostic et Durabilité (GC2D), Institut des Procédés Appliqués aux Matériaux (IPAM), and Lalande, Michèle
Subjects: [SPI]Engineering Sciences [physics], [SPI] Engineering Sciences [physics], ComputingMilieux_MISCELLANEOUS
Abstract: Cet article présente les avancées d’un travail collaboratif entre deux Laboratoires de l’Université de Limoges : l’un spécialisé dans les systèmes électroniques et réseaux intelligents (XLIM) et l’autre en Génie Civil (GEMH). Le point d’intérêt commun est la gestion optimale d’énergie des bâtiments accueillant du public. Le caractère prévisible des scénarios d’usage, et l’importance des charges internes (occupants, éclairage) rendent intéressant de compléter les techniques correctives classiques dans la régulation des systèmes par des stratégies prédictives reposant sur de la modélisation. Sur l’exemple particulier d’un amphithéâtre, l’article présente l’architecture et le mode de communication du réseau fin de capteurs sans fil, et l’utilisation des mesures pour alimenter un modèle de simulation thermique dynamique développé en interne. Les résultats de la simulation en termes de température et humidité relative ambiantes et de concentration en CO2 sont confrontés avec les mesures. Bien qu’étant globalement validés, les résultats montrent l’influence importante de perturbations difficilement mesurables telles que les débits de circulation d’air dus aux ouvertures des portes., Academic Journal of Civil Engineering, Vol 35 No 1 (2017): Special Issue - RUGC 2017 Nantes
Published: 2020
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49. Development of a Thermal Energy Storage Pressed Plate Ceramic Based on Municipal Waste Incinerator Bottom Ash and Waste Clay

Author: A. Meffre, Quentin Falcoz, Vincent Goetz, D. Pham Minh, Ange Nzihou, Nicolas Tessier-Doyen, N. Lopez Ferber, Procédés, Matériaux et Energie Solaire (PROMES), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Axe 1 : procédés céramiques (SPCTS-AXE1), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Université de Perpignan Via Domitia (UPVD), IFP Energies nouvelles (IFPEN), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre de recherche d'Albi en génie des procédés des solides divisés, de l'énergie et de l'environnement (RAPSODEE), Centre National de la Recherche Scientifique (CNRS)-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), SAS Eco-Tech Ceram, Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: 0106 biological sciences, Environmental Engineering, Materials science, Municipal solid waste, Incinerator bottom ash, Waste-based ceramic, 020209 energy, Sintering, 02 engineering and technology, engineering.material, Thermal energy storage, 01 natural sciences, 12. Responsible consumption, [SPI]Engineering Sciences [physics], 010608 biotechnology, Filler (materials), 0202 electrical engineering, electronic engineering, information engineering, Ceramic, Waste Management and Disposal, ComputingMilieux_MISCELLANEOUS, Pressing, [SDE.IE]Environmental Sciences/Environmental Engineering, Renewable Energy, Sustainability and the Environment, Metallurgy, Thermal energy storage material, [CHIM.MATE]Chemical Sciences/Material chemistry, Municipal waste incinerator bottom ashes, Incineration, visual_art, visual_art.visual_art_medium, engineering
Abstract: International audience; Pressed plates ceramics made of gross-milled bottom ashes and waste clay, were made using technologies available in the building bricks and tiles industry, to ease production upscaling at low-cost. These sintered ceramics are intended for use as a high-temperature thermal energy storage material. They represent an alternative to the waste-based petrurgic ceramics previously developed for this application. Post-treated incinerator bottom ashes from a commercial incinerator were collected, characterized and processed to form ceramic materials, using clay as a binder. Ashes were milled, dried, and mixed with various amounts of an illitic clay (produced as washing mud by a quartz quarry in proportions from 20 to 70% dry weight) prior to uniaxial pressing (12 × 5 × 1 cm slabs) and firing at various temperatures, ranging from 1050 to 1125 °C. The sintered samples have been characterized in terms of volumic mass, mechanical strength, thermal capacity and thermal conductivity. Their mineral structure has also been studied. The resulting sintered ceramics exhibit relatively high mechanical resistance and low thermal conductivity, along with moderate volumic mass. These properties allow envisioning the use as filler material for thermocline thermal storage systems (structured beds), and could be interesting for further work regarding applications in the construction field (bricks, tiles, pavements…).
Published: 2020

50. Elaboration and Characterization of Materials from the LaMnO 3 –BiMnO 3 Binary System

Author: Mourad Djahmoum, Omar El Kechai, Pascal Marchet, Université Mouloud Mammeri [Tizi Ouzou] (UMMTO), Axe 3 : organisation structurale multiéchelle des matériaux (SPCTS-AXE3), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)
Subjects: Phase transition, Materials science, semiconductor materials, Semiconductor materials, perovskites, 02 engineering and technology, ceramics, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Materials Chemistry, Binary system, Ceramic, Electrical and Electronic Engineering, Elaboration, Surfaces and Interfaces, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Characterization (materials science), phase transitions, Chemical engineering, visual_art, visual_art.visual_art_medium, solid solution, 0210 nano-technology, Solid solution
Abstract: International audience; The study of the La(1-x)BixMnO3 system was carried out using X-ray diffraction and electrical measurements. A continuous solid solution was evidenced for the LaMnO3 rich part of this system (x ≤ 0.6). According to the analyses of XRD results, a rhombohedral symmetry (3) was observed for x ≤ 0.4 and a cubic structure for x = 0.5. The structural study allowed to determine an increase of the mean perovskite lattice parameter, together with a decrease of the rhombohedral angle up to a cubic symmetry for x = 0.5. For x > 0.6, the system is no more single-phased. Impedance measurements were carried out for ceramics in a wide frequency range (100 Hz-1 MHz), between room temperature and 800°C. The exponential decrease of the AC conductivities (σAC) and the room temperature values correspond to a semiconducting behavior. DC conductivity measurements (σDC) were also performed below room temperature (25K < T < 300K). The results evidence for a metal-insulator phase transition. For the exponential part of the σDC curves, the gap energy is between 0.1 and 0.2 eV, confirming the semiconductor behavior of these materials.
Published: 2020

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