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The thermal behavior of the radioactive graphite–argon system at a pressure of 105 Pa was studied by thermodynamic simulation. The distribution of the elements of the system by phases and the thermophysical properties of the system are determined.

Phase equilibria of the CaO-Gd2O3-SiO2 slag system at 1773 K and 1873 K were investigated by characterizing equilibrated samples with electron probe microanalysis (EPMA). Four three-phase equilibria and five two-phase equilibria are formed in the CaO-Gd2O3-SiO2 ternary system at 1773 K in argon atmosphere. While three three-phase equilibria, six two-phase equilibria and one liquid phase are presented in the system at 1873 K. The isothermal section of the phase diagram is thereafter constructed based on the experimental results. The feasibility of the rare earth recovery is also discussed based on the phase relations.

We propose a method to identify calcium aluminate inclusions in calcium-treated aluminum-killed steels (Ca12Al14O33, CaAl4O7, CaAl12O19, and Al2O3) using cathodoluminescence (CL) analysis. Such inclusions result in nozzle clogging and melting of the stopper rod during continuous casting. We obtain CL images and CL spectra of calcium aluminate inclusions in model samples of calcium-treated aluminum-killed steel. The model samples are prepared by heating mixtures of Fe powder, Al powder, and Ca shot at 1550 °C in an argon atmosphere. On the basis of the CL colors and CL spectra of the calcium aluminate inclusions, we demonstrate that it is possible to distinguish Ca12Al14O33, CaAl4O7, CaAl12O19, and Al2O3 inclusions from CaAl2O4 and Ca3Al10O18 inclusions, which do not cause nozzle clogging and melting of the stopper rod, by comparing CL images obtained using digital cameras with and without a built-in filter. The acquisition times for the CL images are less than 10 seconds. Thus, the method we present here can be applied for the rapid detection of harmful calcium aluminate inclusions during continuous casting. The CL spectra also provide basic information to specify compositions in agglomerated calcium aluminate inclusions.

Mg-AB5 composites are promising systems for hydrogen storage applications, due to their possibility of hydrogen cycling at relatively low temperatures. Traditionally, these composites are mainly processed by high-energy ball milling (HEBM) techniques employing longer processing times. In this study, cold rolling was applied to prepare MgH2 LaNi5 composites and the hydrogen storage properties were investigated. The materials were processed using a vertical rolling mill under argon atmosphere, leading to a good homogeneity and no contamination at shorter processing times. The mixture of MgH2-1.50 mol.% LaNi5 showed the best hydrogen storage properties at 200 °C and 100 °C and the lowest desorption temperature even when compared to cold rolled MgH2. The results indicate that the composite MgH2 LaNi5 is transformed into a mixture of three phases MgH2, Mg2NiH4 and LaH3 upon hydrogen absorption/desorption cycles. The synergetic effect among these phases when in appropriate proportion in the sample seems to play a crucial role in the acceleration of hydrogen absorption/desorption kinetics at lower temperatures in comparison to MgH2.

Fe–Ni–Cr-based super-high-strength maraging stainless steels were generally realized by multiple-element alloying under a given heat treatment processing. A series of alloy compositions were designed with a uniform cluster formula of [Ni16Fe192](Cr32(Ni16–x–y–z–m–nMoxTiyNbzAlmVn)) (at.%) that was developed out of a unique alloy design tool, a cluster-plus-glue-atom model. Alloy rods with a diameter of 6 mm were prepared by copper-mold suction-cast processing under the argon atmosphere. These alloy samples were solid-solutioned at 1273 K for 1 h, followed by water-quenching, and then aged at 783 K for 3 h. The effect of the valence electron concentration, characterized with the number of valence electrons per unit cluster (VE/uc) formula of 16 atoms, on microhardness of these designed maraging stainless steels at both solid-solutioned and aged states was investigated. The relationship between alloy compositions and microhardness in maraging stainless steels was firstly established by the random forest (RF, a kind of machine learning methods) based on the experimental results. It was found that not only the microhardness of any given composition alloy within the frame of cluster formula, but also the alloy composition with a maximum microhardness for any given VE/uc, could be predicted in good agreement with the guidance of the relationship by RF. The contributions of minor-alloying elements to the microhardness of the aged alloys were also discussed.

RE-Mg-Ni-based alloys with their unique superlattice structures have been considered to be possible candidates for hydrogen storage containers as well as electrodes in Ni-MHx batteries. In this study, mechanical alloying with subsequent annealing in the argon atmosphere at 1123 K for 0.5 h, was applied to produce the La1.5-xGdxMg0.5Ni7 (0 ≤ x ≤ 1.5) alloys. Hydrogen storage and electrochemical properties of the synthesized material have been investigated. For example, at the 50th cycle the La1.5Mg0.5Ni7 material shows a much lower reversible electrochemical capacity than La1.25Gd0.25Mg0.5Ni7 alloy. Additionally, the partial substitution of La by Gd improves the kinetics of hydrogen absorption. On the other hand, the stability of the electrochemical discharge capacity increases with the increasing value Gd up to x = 1.0. However, a significant reduction in the discharge capacity was observed for the Gd content above x = 0.25. From the application point of view, only La1.25Gd0.25Mg0.5Ni7 alloy show great potential in the future application as electrode material in Ni-MHx batteries.

A Mo-Si-B coating was prepared on an Nb-Si based alloy by detonation-gun spraying of Mo followed by co-deposition of Si and B via pack cementation. The microstructural evolution and interdiffusion behavior of the coating/substrate system were investigated by annealing for different times at 1250 °C in argon atmosphere. The results show that the interdiffusion zone has a two-layer structure consisting of (Mo, X′)5Si3 (X’ = Nb, Ti, Cr, Hf) and (Nb, X)5Si3 (X = Ti, Cr, Hf), respectively. The growth of the transitional layer, which obeys a parabolic rate law, is dominated by the inward diffusion of Si from the outer layer to the substrate. The interdiffusion coefficients of Si in the transitional layers are calculated using a modified method based on the Boltzmann-Matano analysis.

MgB2 wires with iridium doping were manufactured using the in-situ technique in a composite Cu-Nb sheath. Reaction was performed at 700°C, 800°C or 900°C for 1h in argon atmosphere. A maximum of about 1.5 at.% Ir replaces Mg in MgB2. The superconducting transition temperature is slightly lowered by Ir doping. The formation of IrMg3 and IrMg4 secondary phase particles is evidenced, especially for a nominal stoichiometry with 2.0 at.% Ir doping. The critical current density and accommodation field of the wires are strongly dependent on the Ir content and are generally weakened in the presence of Ir, although the effect is less pronounced at lower temperatures.

Highly connective network of electromagnetic materials is greatly benefit for high-performance electromagnetic radiation elimination. In this work, we constructed an three-dimensional (3D) electromagnetic network using multi-walled carbon nanotubes (MCNTs) as wires and metal organic frameworks (MOFs) as junctions. After treating the networks by calcination at 500 °C under argon atmosphere, a 3D Co/C-MCNTs hybrid network formed and displayed excellent electromagnetic waves absorption (EWA) performance. The enhanced mechanism of the network structure was thoroughly explored and analyzed. This research provides valuable guidance to the design of high-performance EWA materials as well as novel MOFs based hybrids.

Kaolins are used in a multiplicity of industries because of unique physical and chemical properties. Relationships between thermal and radioactivity properties are discussed in its application as a building material. Super-fine kaolin powder with particle sizes about 30 mu m was analyzed. Simultaneous TGA/DTA analysis was performed on powder samples at various heating rates in an argon atmosphere. Based on investigated thermal properties, it was concluded that dehydroxylation process can vary depending on the characteristics of starting material. The maximum degree of the dehydroxylation (D (T)) was obtained at the lowest rate of heating (D (T) = 60.79% for 10 A degrees C min(-1)). With an increase in the heating rate, decline in D (T) value was observed. Based on comprehensive testing, it was identified that the degree of dehydroxylation does not drop below 50%. It was concluded that appointed experimental conditions seem sufficient admissible for obtaining degree of dehydroxylation (D (T)) higher than 50%. In order to safe use of kaolin as a building material from the standpoint of radiological safety, content of natural radionuclides was determined by gamma spectrometry.

The present study aims to fabricate fullerene (C60) reinforced magnesium matrix composite via semi powder metallurgy in hot press system under high purity argon atmosphere. Improvement of wear resi...

The temperature dependence of the enthalpy increment of tin in the temperature range 800–1475 K is studied because of the fact that the reference data on the thermophysical properties of liquid tin at high temperatures are conflicting and ambiguous. The measurements were carried out by drop calorimetry in an argon atmosphere using a high-temperature SETARAM MHTC calorimeter. The experimental results are compared with the well-known reported values to choose the most reliable source of reference data.

The effect of the chromium concentration on the magnetic properties of Fe–Cr precursors for hard-magnetic Fe–Cr–Co materials is studied. Nitrogen used as a sintering atmosphere and a long annealing time enhance are found to increase the coercive force Hc of the materials. The phase formation in Fe–30% Cr alloys is traced during heat treatment in nitrogen and argon atmosphere using thermal analysis.

The effect of thermomechanical treatment on mechanical and electrical properties of the Cu-Cr-Zr alloy was experimentally investigated through the Vickers micro-hardness, tension tests, and four-point probe method at room temperature. Three sets of experiments were carried out employing a commercially available alloy that was solution treated at 980 ˚C for 1 h in an argon atmosphere and water quenched. The order of the wire drawing or continuous hybrid processing and aging was varied to determine the effect of the thermomechanical treatment condition on material properties. The three-pass wire drawing and two-pass continuous hybrid processes after aging at 450 ˚C produced 508.8 MPa with 80.1% IACS and 529.4 MPa with 78.6% IACS, respectively. In conclusion, the continuous hybrid process might be an alternative to achieve the economical manufacturing in meeting the requirements for better strength and comparable electrical conductivity of the existing material compared to the conventional wire drawing.

In an attempt to provide a new advanced carbide/nitride ceramic material with high sinterability and density for high-temperature and solar energy applications, this work inspected the effect of different sintering atmospheres on the processing of near-fully dense SiC/AlN ceramic composites. Several SiC/AlN (0 – 40 wt.%) composites were produced by pressureless sintering at a temperature of 2080°C for 2 hrs using a sintering additive of 2.5% yttria + alumina. Influences of argon/vacuum and nitrogen/vacuum atmospheres on the reaction response and the densification behavior of SiC/AlN composites were examined and analyzed. Results show that sintering of SiC/AlN ceramics in a nitrogen atmosphere increases mass loss of the different composites during sintering and leads to a decrease in their densification parameters. However, sintering in an argon atmosphere promotes both the sintering and densification processes, making argon atmosphere more convenient for sintering SiC/AlN ceramics. The use of SiC/AlN composites prepared by pressureless sintering is suitable for high-temperature applications.

A novel metal–organic-framework (MOF) composition-tuning strategy has been developed for the synthesis of well-defined hierarchical structures, which is based on reactivity modification of the zeolitic imidazolate framework (ZIF)-67. Typically, 1D ZIF-67@Ni-1,3,5-benzenetricarboxylic acid (ZIF-67@Ni-BTC) nanorods are obtained, which can be easily transformed into 1D graphene-coated NiCo2O4 (NiCo2O4@graphene) nanorods by an annealing treatment in an argon atmosphere, followed by oxidation in ambient air. By controlling the reaction time, novel structures such as hollow ZIF-67@Ni-BTC polyhedra and hollow ZIF-67@Ni-BTC polyhedra/ZIF-67@Ni-BTC nanorods can also be achieved. By virtue of the advantages of the structure and graphene coating, NiCo2O4@graphene nanorods as lithium storage materials exhibit high Li-storage capacity, excellent rate capability and remarkable cycling stability.

ODS ferritic steels were produced by mechanical alloying (MA) in either attritor or planetary ball mills under argon atmosphere and hot extrusion. Milling in argon with controlling excess oxygen (Ex.O) and nitrogen was effective to reduce the particle size of MA powders. Coarse Al2O3 particles and fine AlN precipitates were found to be formed in an Al added steel when the Ex.O and nitrogen concentrations are increased. Lowering the Ex.O and nitrogen concentrations in ODS ferritic steels acted as a key parameter for enhancing their impact properties.

In this work we report the results of experimental studies of the phase composition and structure of the nanodispersed Al–O powder produced by the plasmodynamic method. Using X-ray diffractometry and transmission electron microscopy, we show that the product contains σ-Al2O3 and MgAl2O4. The phase composition evolution of the initial product of plasmodynamic synthesis is studied during its heat treatment. Thermogravimetric analysis in an argon atmosphere shows no changes in mass of the sample weighed when it is heated, while differential scanning calorimetry studies indicate a marked manifestation of the endothermic effect.

Mg-11Zn-26Fe-7Cu-4Co, Mg-11Zn-6Fe-0.2Cu-0.3Co, and Mg-19Zn-17Fe-28Cu-18Co are produced by using a powder metallurgical process followed by sintering in an argon atmosphere. Potentiodynamic polarization and electrochemical impedance spectroscopy are applied to study the corrosion behavior and corrosion inhibition by coumarin of Mg-11Zn-26Fe-7Cu-4Co, Mg-11Zn-6Fe-0.2Cu-0.3Co, and Mg-19Zn-17Fe-28Cu-18Co in Hanks’ solution. Potentiodynamic polarization and electrochemical impedance spectroscopy characterization reveal that Mg-19Zn-17Fe-28Cu-18Co high entropy alloys exhibit better corrosion resistance than Mg-11Zn-26Fe-7Cu-4Co, and Mg-11Zn-6Fe-0.2Cu-0.3Co in Hanks’ solution. The addition of coumarin effectively inhibits corrosion of Mg-11Zn-26Fe-7Cu-4Co, Mg-11Zn-6Fe-0.2Cu-0.3Co, and Mg-19Zn-17Fe-28Cu-18Co high entropy alloys in Hanks’ solution.

Studying of field electron emission properties of carbon cathodes operating under technical vacuum conditions is a promising scientific field. Massive cathode made of commercial fine-grained graphite of MG (Russian abbreviation) grade is being investigated. Experiments on obtaining current-voltage characteristics and long-term testing are being carried out. The emitter made of fine-grained graphite demonstrates good emission properties under technical vacuum conditions. Carbon cathode is capable of operating at pressures up to 2×10–2 Pa. Increased pressure in the vacuum chamber leads to deterioration of cathode emission properties. Electric field enhancement factors were calculated for all stages of studies. Analysis of experimental data demonstrates decrease in enhancement factor due to ion bombardment of cathode surface during exploitation. This results in higher electric field for operation of investigated graphite cold cathodes.

In this study, a cylinder of fine-grained carbon-bonded alumina was pressed uniaxially at high temperatures in an argon atmosphere. The resulting changes in mechanical properties, physical properties and microstructure were described with various techniques. The porosity of the material was found to have decreased significantly, leading to higher density, higher dynamic Young's modulus, higher strength and increased hardness. Additionally, gradients in porosity and hardness were observed that resulted from inhomogeneous temperature distribution during compression. Possibilities and conditions for the production of graded refractory materials can be deduced from the results.

To investigate the effect and mechanism of π–π interaction between carbon nanotubes (CNTs) and phenyl groups on the thermal stability of silicone rubber (SR), three kinds of silicone rubber with different phenyl content were used to prepare CNTs/SR composites in present study. Raman spectroscopy and X-ray photoelectron spectroscopy demonstrated that the π–π interaction between CNTs and phenyl groups in composites is enhanced with phenyl content increasing. The results of thermogravimetric analysis and tensile testing before and after aging indicted the π–π interaction makes CNTs improve the thermal stability of phenyl SR more efficiently than that of methyl vinyl SR. The T 5 (defined as the temperature for 5% mass loss) of CNTs/SR-3 (with 10–20% phenyl content) is increased by 19.4 °C compared to that of SR-3, and the final residual mass of CNTs/SR-3 (31.9%) is much higher than other samples under argon atmosphere.

The effect of two different annealing processes on the microstructure and barrier-forming ability of Cu-Zr alloy films has been investigated. Cu-Zr alloy films were deposited directly onto SiO2/Si substrates via direct current magnetron sputtering and subsequently annealed by the vacuum annealing process (VAP) or rapid annealing process under argon atmosphere at temperatures 350°C, 450°C, and 550°C. Then, the microstructure, interface characteristics, and electrical properties of the samples were measured. After annealing, the samples showed a preferential (111) crystal orientation, independent of the annealing process. After two annealing methods, Zr aggregated at the Cu-Zr/SiO2 interface and no serious interdiffusion occurred between Cu and Si. The leakage current measurements revealed that the samples annealed by VAP show a higher reliability. According to the results, the vacuum annealing has better barrier performance than the rapid annealing when used for the fabrication of Cu-based interconnects.

The objective of the present work is to characterize the wear behavior of a cryogenically treated low-carbon AISI 420 martensitic stainless steel, by means of ball-on-disk tribological tests. Wear tests were performed under a range of applied normal loads and in two different environments, namely a petrolatum bath and an argon atmosphere. Wear tracks were analyzed by both optical and scanning electron microscopy (SEM) and Raman spectroscopy to evaluate wear volume, track geometry, surface features and the tribolayers generated after testing. This paper is an extension of the work originally reported in the VIII Iberian Conference of Tribology [G. Prieto, W.R. Tuckart, VIII Iber. Conf. Tribol., Cartagena, España, 2015: pp. 68?75].In this study, it has been experimentally demonstrated that cryogenically treated specimens showed a wear resistance improvement ranging from 35 to 90% compared to conventionally treated ones. Fil: Prieto, Germán. Universidad Nacional del Sur. Departamento de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Tuckart, Walter Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería; Argentina

Al 2 O 3 -SiC composite powders were successfully fabricated from coal ash by carbothermal reduction reaction (CRR) method in argon atmosphere. The effects of raw materials ratio, reaction temperature, La 2 O 3 and Sm 2 O 3 additions on the synthesis process were investigated in detail. Phase compositions and microstructures of Al 2 O 3 -SiC composite powders were characterized by XRD and SEM. Proper processing parameters and rare earths addition amounts were determined, and the formation process of Al 2 O 3 -SiC powders was also discussed.

The isothermal and cyclic corrosion behavior of yttria (Y2O3)-stabilized zirconia (ZrO2) in a LiCl-Li2O molten salt were investigated at 650 °C in an argon atmosphere. During isothermal and cyclic ...

Formation of the Ni2MnSn Heusler alloy by solid state reaction from elemental powders was investigated. The solid state reaction was conducted in a planetary ball mill under argon atmosphere up to 28 h of milling. During the milling, after selected intervals samples were collected and studied by X-ray diffraction to record phase changes. After 16 h of milling a two phase mixture (Ni2MnSn with B2 structure and NiMnSn with C1b structure) was found. Further, the thermal stability of the samples was investigated, and phase precipitation was found. The formed phases are ordered Full Heusler (L21) and Ni3Sn2. The formation temperature and their amount evolution versus temperature and milling time is discussed. An inversion of the formation temperature was found for the L21 and Ni3Sn2 phase, during the DSC study, in relation with the milling time. For the B2 compound a stability range on temperature was identified (from 25 to 300 °C), as well as for the L21 and Ni3Sn2 phases (from 400 to 600 °C) in the case of 28 h milled sample. The milled and annealed sample exhibit nanocrystalline state, formation mechanism under temperature was concluded to be by precipitation.

Strain controlled thermomechanical fatigue (TMF) behavior of Cu-Cr-Zr-Ti alloy was studied in the temperature range of 375–525 °C in high purity argon atmosphere under both in-phase (IP) and out-of-phase (OP) loading. In the case of OP TMF tests, the material exhibited continuous hardening without any saturation of stress. On the other hand, it showed cyclic hardening for the first few cycles followed by saturation of stress in IP TMF tests. The material exhibited superior lives under OP TMF loading compared to that under IP TMF loading especially at lower strain amplitudes. This may be attributed to the fact that the material experienced peak tensile stress at lower temperatures in OP TMF tests, where the resistance to crack initiation is expected to be higher. Microstructural observations and fractographic studies indicated mixed mode of fracture involving Intergranular facets and transgranular cracking in both IP and OP TMF tests.

Objectives: This study evaluated the effect of argon atmosphere compared with vacuum during porcelain firing on the fracture strength of crowns made of porcelain and electron beam melted (E...

The marginal adaptation of prosthetic crowns is still a significant clinical problem.The purpose of this in vitro study was to evaluate the marginal deficiency and misfit of Ni-Cr alloys with and without beryllium under different casting conditions.Four casting conditions were selected: flame-torch, induction/argon, induction/vacuum, and induction/air; and 2 alloys were used, Ni-Cr-Be and Ni-Cr. For each group, 10 metal specimens were prepared. Silicone indirect impressions and analysis of the degree of rounding were used to evaluate the marginal deficiencies of metal copings, and a standardized device for the setting pressure associated with optical microscopy was used to analyze the marginal misfit. Results were evaluated with 2-way ANOVA (α=.05), followed by the Tukey honest significant difference post hoc test, and the Pearson correlation test (α=.05).Alloy (P.001) and casting technique (P.001) were shown to affect marginal deficiencies. The Ni-Cr cast using the torch technique showed the highest marginal deficiency, and the Ni-Cr-Be cast in a controlled argon atmosphere showed the lowest (P.001). Alloy (P=.472) and casting techniques (P=.206) did not affect the marginal misfit, but significant differences were found in the interaction (P=.001); the lowest misfit was achieved using the Ni-Cr-Be, and the highest misfit occurred with the molten Ni-Cr, using the cast torch technique. No correlation was found between deficiency and marginal misfit (r=.04, P=.69).The interactions demonstrated that the alloy containing beryllium that was cast in an argon atmosphere led to reduced marginal deficiency. Improved marginal adaptation can be achieved for the same alloy by using the torch technique.

Analysis on the source of CO is very important for prevention of coal spontaneous combustion. In this article, a method of identifying primary CO in coal seams based on an oxygen isotope method is proposed through research. Tests on the oxygen isotopes (δ18O) of CO were generated in coal oxidization reaction and coal pyrolysis reaction. It is found that δ18O of CO will reduce with rising temperature in both reactions, with δ18O of CO being 15–20‰ in air atmosphere and that being 25–28‰ in argon atmosphere in the temperature range of 130–220°C, confirming that the sources of oxygen atoms of CO vary with different atmospheric conditions. Through collecting and testing a number of gas samples from the coal seam and roof in the coal mine, their δ18O of CO is found to be 35.2–37.3‰. The result would improve the prevention of coal spontaneous combustion.

Cr (0.2 at.%) and Nd (0.8 at.%) co-doped Lu3Al5O12 ceramics were fabricated with MgO as the sintering additive. The addition of a small amount of MgO can affect the grain boundary mobility and influence the number and location of micropores in ceramics during the sintering process. The results show that when the MgO content is 0.02 wt.%, high-transparency Cr,Nd:LuAG ceramics can be obtained by vacuum sintering at 1670 °C for 5 h followed by hot isostatic pressing (HIP) post-sintering at 1750 °C in an argon atmosphere (P = 200 MPa) for 5 h. The optimum in-line transmittance of the HIPed Cr,Nd:LuAG ceramics (3 mm thick) is 83.5% at a wavelength of 840 nm and 84.0% at 710 nm.

Recently, Ni-free shape memory Ti-based alloys (composed of the biocompatible β-stabilizing elements such as Ta and Nb) are extensively studied. In this work, new Ni-free Ti-17Nb-6Ta is presented as a candidate for shape memory alloys with high biocompatibility. This alloy produced using arc-melting in argon atmosphere, followed by solution annealing at 900° C for 30 min. β-phase is the predominant phase beside α” martensite phase. Stress induced martensitic transformation is observed after cold rolling and during bending tests as measured by XRD. The hardness of the bended wire in the solution treated condition was around 330HV. While the cold rolled wire hardness before bending was 300 HV. The superelasticity and shape memory effect was investigated through bending tests of alloy wires. The cold rolled wire showed higher superelasticity than shape memory effect. But superelasticity and the shape memory effect were almost similar with the solution treated wire. Also, the total spring back in cold rolled wire is higher compared with solution treated wire.

Evolution of hydrogen during the plastic state is a key parameter in coke making for the production of quality coke. Based on this phenomenon, a new devolatilization method has been developed for accessing the coking property of coals using the evolution of H2 during thermogravimetric–mass spectrometer (TG-MS) analysis. Four coals having different coking potentials, commonly used in steel industries, were considered. The investigation was performed at temperatures up to 1100 °C in an argon atmosphere under a constant heating rate of 3 °C/min to simulate the coking environment. Nonisothermal kinetics is considered as a good indication of different reaction regimes during pyrolysis, which is generally done through TGA alone. In this study evolution of H2 is used to develop nonisothermal kinetics through a new quantification approach. Finally, a definite and more generic correlation was established, based on H2 enrichment in volatiles around specific temperature zones, for measuring the exact coking behavior...

An investigation was carried out to understand the effects of Co, Ti and Si additions to the AlCuNiFe entropy alloys on the microstructure, hardness and wear properties. The entropy alloy samples were prepared by an arc melting process under an argon atmosphere. Hardness and wear rate were measured using a microhardness tester and a Pin-On-Disc wear tester respectively. EDAX and XRD analyses were also carried out. The entropy alloys showed a high hardness and a low wear rate compared to several conventional alloys. Si and Ti contribute significantly to the increase in the hardness when compared to Co in the AlCuNiFe system. Si tends to form a separate phase due to the effect of entropy of mixing. The results of this study are comparable to those of previous works.

This article describes investigations into the properties of thin films of tungsten sulfide and copper sulfide produced by magnetron sputtering on glass substrates in argon atmosphere. Transmittance spectra of the obtained films are studied by spectrophotometry in the range from 300 to 900 nm; the band gaps are determined. The thickness of the obtained films varies in the range of 0.5–1 μm.

Hexagonal plate-like Al 4 Si 2 C 5 particles were synthesized for the first time via a carbothermal reduction process with controlled heating temperature and raw materials ratio, and their oxidation behavior was investigated. Al 4 O 4 C, Al 2 OC, SiC and Al 4 SiC 4 formed as intermediate products when the batch mixture was heated in argon atmosphere, and Al 4 Si 2 C 5 then formed at above 1800 °C. Possible reaction mechanisms responsible for the formation of this ternary carbide were discussed based on the reactions at the initial and later stages of the carbothermal reduction process. Al 4 Si 2 C 5 added to the Al 2 O 3 –C refractory initially reacts with CO to form Al 2 O 3 , SiO 2 and C. After the reaction, Al 2 O 3 react with SiO 2 to form mullite on the surfaces of the refractories, which inhibit the oxidation of the refractories.

Cold rolling can significantly increase hydrogen storage properties of Mg and its alloys. Therefore in this paper, two important cold rolling processing parameters were investigated: the amount of passes and the roll rotation frequency, which directly influence particle and crystallite sizes and thus the interfaces for hydrogenation/dehydrogenation. Extensive cold rolling was conducted with MgH2 powder as starting material under an argon atmosphere to avoid contamination. The results indicate that the cold rolled MgH2 was free from oxides even after 50 cold rolling passes. Additionally, considerable improvements in the hydrogen storage properties were achieved with higher amounts of cold rolling passes. A similar effect could also be found for higher roll rotating frequency. This beneficial outcome originated from three important aspects: the decrease of the crystallite size reaching 88% reduction after 50 passes and 82% after 35 passes with rotating frequency of 50 rpm, the refinement of particle size, and a change in the morphology of the initial MgH2 powder from granules to flakes, and ultimately to small particles.

Domestic detergents are widely used and the detection of detergent residues on tableware is closely related to people's health. As is known to all, it is difficult to sample and measure the residual detergent on tableware. The purpose of this paper is to explore a rapid in situ detergent residues detection method. We have using laser-induced breakdown spectroscopy (LIBS) measured the detergent on porcelain plate. Based on our previous research, we further studied the spectra of detergent in argon atmosphere, and compared them with that in air. We found the spectral characteristics of the cyanogroup (CN) were related to the air around the measuring point. It was indicated that CN could not as previously speculated be used as the LIBS detection feature of detergent. The improvement of signal-to-noise ratio (SNR) in argon environment was proved and we made a study of semi quantitative measurement by the peak height of 330.30 nm in argon atmosphere. An experiment measuring the detergent on tableware after washed was taken. It illustrated that the LIBS technology has promising potential applications for tableware cleaning process or food production process as a means of on-line detection.

Ultrathin graphitic carbon nitride (g-C3N4) nanosheets were synthesized via thermal exfoliation of bulk urea-derived g-C3N4 under an argon atmosphere. As a visible-light responsive photocatalyst, this material exhibits a much superior photocatalytic activity in pollution degradation and H2 evolution than bulk g-C3N4, as a result of the extended region of visible light response and the enhanced surface area of ultrathin g-C3N4 nanosheets. These findings may provide a promising and facile approach to the design of high-performance photocatalysts.

Steady-state photolysis of triarylphosphines, Ar3P, under an argon atmosphere in a solvent with the structure CH3X (X = CN, COOC2H5, COCH3) afforded an adduct with the solvent molecule, Ar2PCH2X, i...

In this study, the porous samples were manufactured through self-propagating high-temperature synthesis (SHS) by adding 10 % Co and Cr to 50 % Ni – 50 % Al powders. 10 % Co and Cr added 50 % Ni – 50 % Al samples were mixed for 12 hours using a mixer with a rotational speed of 300 rpm and compacted under 100 MPa pressure. The obtained samples were then synthesized by moving them to an argon atmosphere and combusted with the aid of a tungsten electrode. The samples that were obtained after the combustion reaction were characterized in terms of their microstructure using SEM-BSE. The elemental and phase analysis were carried out using EDS and XRD, respectively. The EDS results showed that the dominant element was Ni and the presence of Co with Cr was less than that of Al. The XRD measurements suggested that the highest peak is belong to NiAl along with the lowest peaks presented by Ni3Al ve NiAl3. Cr added NiAl alloy was found to present the highest hardness value after performing hardness measurements. In addition, adding Co to NiAl intermetallic structure was also found to help increasing the hardness

In the present research, five filled HTV silicone rubber with different ATH filler content were manufactured and analyzed by TGA measurement in Argon atmosphere. The crystal structure of ATH filler was measured by XRD analysis, based on the XRD results, it can be confirmed that ATH filler used in this research is the Gibbsite. The weight loss process of HTV silicone rubber during the TGA process was identified, two loss peaks were observed in the derivative of TGA curve, one was attributed to the dehydration of ATH filler and the other one was attributed to the pyrolyzation of silicone rubber matrix. Furthermore, a calculation method for obtaining each component weight in HTV silicone rubber based on TGA results was proposed, based on this calculation method, the detailed content information of these five HTV silicone rubber was obtained. Based on this research, it can be concluded that the TGA analysis of filled HTV silicone rubber is an effective way to obtain the weight of each component in HTV silicone rubber.

TiB2 nanosheets were synthesized by the borothermal reduction of TiO2 in flowing argon atmosphere with the assistance of MgCl2. Phase transformation was studied by XRD and micromorphology of products was studied by SEM and TEM. In the experiment, the prepared TiB2 formed the nanoscale lamellar structure. These lamellas agglomerated together to be a net-like structure. Effects of reduction temperature, addition of MgCl2, and its amount were discussed in detail. The results indicated that the presence of MgCl2 accelerated the mass transfer of reactant. Moreover, the co-effects of MgCl2 and B2O3 contributed to the formation of TiB2 nanosheets. TiB2 could dissolve in MgCl2 and B2O3 at high temperature and then recrystallized during the cooling process. The products with a specific surface area of 99.32 m2 g−1 were obtained at 1373 K after reacting for 4 h with a MgCl2:TiO2 molar ratio of 1:1.

International audience; Mg-Sn thin films (21 ≤ at. % Sn ≤ 42.5) were deposited by magnetron sputtering in the argon atmosphere. The structure and morphology of the films were characterized as a function of the composition. Mg2Sn structure was changed from stable face-centered cubic to metastable orthorhombic structure while the content of Sn in the films increased. The influence of this structural modification on thermoelectric properties was discussed in a wide range of temperatures (30–200 °C). The film carrier concentration and mobility were measured to explain the electronic transport behavior as a function of the film structural modifications. The maximum figure of merit ZT ≈ 0.26 at 200 °C was reached for the film with 36 at. % Sn while a mixture of cubic and orthorhombic Mg2Sn structures coexisted. An annealing treatment was performed under vacuum (∼10−4 Pa) at different temperatures (up to 600 °C) to determine the limit of structural and morphological stability of this film.

The isothermal hot pressing (IHP) of skimmed aluminium dross, considered in this study, was performed under laboratory conditions using a cylindrical pressing model made from high-temperature stainless steel. The pressing model was inserted into an electrical furnace with a protective argon atmosphere. The temperature of the pressing was within the interval 650–900 °C, while the applied pressure varied between 5 and 50 bars. The laboratory results showed that when using IHP it is possible to reduce the remaining aluminium content in “pressed dross skulls” below 10%.