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A new type of high-temperature-resistant SiZrBOC ceramics was prepared by sol-gel method using polymethyl-hydro siloxane (PMHS), boric acid (B(OH)3), and n-propyl zirconate (Zr(OPr)4) as raw materials. After high-temperature pyrolysis, the SiZrBOC precursor was transformed into a crystalline ceramic material with a yield of 89.5 wt%. Fourier infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) were applied to characterize the polymer-ceramic conversion process and thermal behavior of ceramic precursors. According to the results, the addition of boron elements led to the formation of Si-O-B links in the system. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the phase composition and microstructure of SiZrBOC ceramics. Finally, the oxidation test at 1200 °C revealed that SiZrBOC ceramics with a boron/zirconium molar ratio of 2.5:1 exhibited the best oxidation resistance at a weight gain of 0.4 wt% only.

It is a challenge to achieve flexibility in purely inorganic piezoelectric materials without organic support, and various thin film flexible inorganic piezoelectric materials has been developed recently. In this work, lead zirconate titanate (PZT) nanofiber membranes were prepared by electrospinning, and a flexible membranes can be obtained by reducing the calcination temperature, and the flexibility was characterized by the three-point method. The fiber membrane was relatively thicker in relative to thin films and confirmed to adsorb Congo Red quickly under the action of ultrasound. The maximum adsorption capacity is 61.78 mg g−1 and saturation time reaches 20 min under ultrasound treatment. In addition, the color change after saturation adsorption can quickly determine the actual load of the fiber membrane. In the future, this load saturation effect can be used to calibrate the relationship between the piezoelectric signal and the adsorption load, so as to obtain more accurate chemical sensors.

The vapor-phase dehydration of 1,3-butanediol (1,3-BDO) to produce 1,3-butadiene (BD) was investigated over yttrium zirconate, Y2Zr2O7, which was prepared through a hydrothermal aging process. 1,3-...

We report a newly developed surface engineering approach for TiO2 nanoparticles toward transparent TiO2/silicone nanocomposites with high refractive index (RI) values. Zirconate coupling agents are adopted on the TiO2 nanoparticles for surface passivation and to enhance the dispersibility of the nanoparticles in organic substrates. The modified TiO2 nanoparticles can be uniformly dispersed in silicone, forming transparent hybrid films with an ultrahigh RI of 2.01. The preparation technique of colloidal TiO2 and polymer-based nanocomposites is simple and suitable for scalable production, which is promising for expanding the application of TiO2 materials in photonic devices.

Nanocrystalline gadolinium zirconate, Gd2Zr2O7, has been prepared by solid-state reaction, using mechanical activation of a stoichiometric mixture of Gd2O3 and ZrO2. The mechanical activation was performed in an AGO-2 centrifugal planetary mill for 10 min. The processes that occurred during heat treatment of the mechanically activated mixture of gadolinium and zirconium oxides were characterized by X-ray diffraction, IR spectroscopy, and a combination of thermoanalytical techniques. The average crystallite size of gadolinium zirconate prepared by calcining the mechanically activated oxide mixture at 1100 and 1200°C for 3 h was 29 and 68 nm, respectively, as determined using the Scherrer formula.

Carbon contamination is a significant concern for proton-conducting oxides in the cerate and zirconate family, particularly for BaCeO3. Here, we use first-principles calculations to evaluate carbon stability in SrCeO3, BaCeO3, SrZrO3, and BaZrO3. The cerates require more carbon-poor environments to prevent carbonate formation, though this requirement can be loosened through the use of more oxygen-poor growth conditions. Carbonate formation is not the only concern, however. We find that interstitial carbon has lower formation energies in the cerates relative to the zirconates, leading to higher carbon concentrations that compete with the desired oxygen vacancy formation. We also examine the mobility of carbon interstitials, finding that both migration barriers and binding energies to acceptors are lower in the cerates. As a result, the cerates are likely to degrade when exposed to carbon at operating temperatures. Our results show definitively why the cerates are less stable than the zirconates with respect to carbon and elucidate the mechanisms contributing to their instability, thereby helping to explain why alloying with zirconium will enhance their operational efficiency.

Lanthanum aluminate-lanthanum zirconate composite was synthesized by using coprecipitation and powders were dried by spray-drying. Pseudoboehmite was used as a precursor of lanthanum aluminate during the precipitation process. Highly crystalline phases were obtained. Lanthanum zirconate exhibits a pyrochlore structure at lower synthesis temperature (>1500°C). Due drying technique lanthanum aluminate particles appear surrounded by lanthanum zirconate. No other remaining phases were observed and the phase distribution in the composite was homogeneous.

OAbstract. One of the approaches that has been done to produce a better performance of an intermediate temperature solid oxide fuel cell (IT-SOFC) is by varying the synthesis methods. This paper focused on the proton conducting electrolyte in particularly barium cerate and barium zirconate system namely BaCe0.9Y0.1O3-δ (BCY) and BaZr0.9Y0.1O3-δ (BZY). Supercritical ethanol processing technique is one of the alternative synthesis routes that able to produce ceramics powder at lower calcination temperature. The samples were synthesized in High-Pressure-High-Temperature (HP-HT) Batch Wise reactor system using ethanol as reaction medium. XRD was used to study the structure of both samples and all the data were refined using Rietveld refinement method by X’pert Highscore software. VESTA software is used to observe the crystal structure for both BCY and BZY samples. Both BCY and BZY have 98.16% and 96.55% purity after being calcined at 700°C and 1100°C, respectively. This study showed that BCY has orthorhombic structure with lattice parameter a=8.76Å, b=6.24Å and c=6.21Å and BZY exhibited cubic structure with a=b=c, and a=4.194Å. It was observed that BCY synthesized by supercritical fluid (SCF) method at reduced calcination temperature exhibited an acceptable value of lattice paramter as compared to other method that used higher processing temperature.

Nanocrystalline YFeO3–CaZr(Ti)O3 powders were synthesized by the sequential deposition method. The structure of the YFeO3–CaZr(Ti)O3 nanocrystals fits into the core–shell spherical particle model. The nanocrystalline YFeO3–CaZr(Ti)O3 powders synthesized contain yttrium orthoferrite and calcium zirconate (titanate) single phases. Materials based on YFeO3–CaZr(Ti)O3 are magnetically soft.

Barium titanate, BaTiO3 [BT] and Barium calcium titanate-zirconate BaCa(Ti Zr)O3 [BCTZ] powders were prepared utilizing sol gel polymeric method using urea formaldehyde resin, as a template. The obtained gel dried at 80°C/48h, then calcined at different temperature 800, 1000 and 1100°C/3h. FT-IR analysis, thermal analysis in terms of DTA-TG were carried to the polymer gel, and gel hosting cations at 80°C. Phase composition using X-ray diffraction (XRD) was investigated to the calcined powder at the previous temperatures, Microstructure using scanning electron microscopy (SEM) was studied at 1100°C/3h. It was found that the pure perovskite of (Tetragonal-orthorhombic-monoclinic) barium titanate [BT] and (Tetragonal-orthorhombic-monoclinic) [BCTZ] powder was obtained at a calcination condition of 1100 °C for 3h.The average crystal size 24.14 nm for BT powder while BCTZ powder recorded 22.83 nm. Uniform grain microstructure powders contain nearly spherical pores was obtained

Samples of titanate zirconate ceramics based on phases of the murataite-pyrochlore series are studied by XPS. The analysis of the surface was performed and the oxidation states of the elements were determined. A comparison of XPS results and data on the total composition of the samples was carried out. On the surface, compared to the bulk, the Ti and Th content is lower, but the Fe content is higher. Despite the introduction of uranium into the blend in the form of UO2 or as uranyl nitrate, the samples contain approximately equal amounts of U(IV) and U(V). Iron is 93% Fe(III) and 7% Fe(II) forms.

The presented article characterized microstructural aspects of thermal barrier coatings (TBCs) analysis using methods of electron microscopy such as electron backscatter diffraction (EBSD), transmission/scanning electron microscopy (S/TEM), and TEM. The analyzed TBC system is based on gadolinium zirconate deposited by air plasma spraying method, and additionally, it was subjected to an oxidation test for 500 hr at a temperature of 1,100°C. Moreover, the morphological characterization of feedstock powder was showed. EBSD analysis revealed the inhomogeneity of feedstock materials in the form of complex phase composition. In the case of deposited coating, this method was used to characterize the crystallite size of zirconate coating and phase composition of thermally grown oxide zone. S/TEM and TEM analysis showed morphological details of this zone but not revealed such phase as perovskite oxide of GdAlO3 type.

Herein, we have reported a novel composite of nitrogen doped reduced graphene oxide (N-rGO) and strontium zirconate (SrZrO3). This new composite (N-rGO/SrZrO3) was synthesized using the reflux method. The physicochemical properties of N-rGO/SrZrO3 were determined using different advanced techniques such XRD, FE-SEM, EDX, FTIR and BET. Furthermore, a glassy carbon electrode was modified with N-rGO/SrZrO3 (GCE-2). This modified electrode was employed for the sensing of HQ. The electrochemically active surface area (ECSA) of this modified electrode (GCE-2) was calculated by employing the Randles–Sevcik equation. Furthermore, GCE-2 exhibited a good detection limit (0.61 μM) including high selectivity towards HQ.

To minimize alteration of the La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF)/Gd0.2Ce0.8O2-δ(CGO20)/Y0.06Zr0.94O2-δ(3YSZ) interface via strontium zirconate formation in solid oxide cells, electron beam physical vapor deposition was employed to manufacture dense, thin gadolinium-doped ceria (CGO) interlayers. CGO layers with thicknesses of 0.15, 0.3, and 0.5 μm were integrated in state-of-the-art 5 × 5 cm2-large electrolyte-supported cells, and their performance characteristics and degradation behavior were investigated. Electrochemical impedance spectroscopy measurements are correlated with a postmortem scanning electron microscopy/energy-dispersive X-ray spectroscopy analysis to show that 0.15 μm-thick layers lead to the formation of a continuous Sr-containing secondary phase at the CGO/YSZ interface, likely related to the formation of a SrO-ZrO2 phase. Major performance losses were confirmed by an increase in both Ohmic and polarization resistance with an increase in the frequency region ∼103 Hz. Cells with 0.3 μm- and 0.5 μm-thick CGO layers showed similar high performance and low degradation rates over a testing period of ∼800 h. The YSZ/CGO interface of the cells with a 0.3 μm-thick CGO layer showed the formation of a discontinuous Sr-containing secondary phase; however, performance losses were still successfully prevented. Furthermore, it is observed that 0.5 μm-thick CGO layers were sufficient to suppress the formation of the Sr-containing secondary phase.

In this study, the effect of mechanical activation of coprecipitated hydroxide precursor on synthesis of gadolinium zirconate Gd2Zr2O7 has been studied. Mechanical activation of the precursor has been performed in an AGO-2 laboratory centrifugal-planetary mill at a centrifugal factor of 20 g with zirconia vials and balls. Particular attention has been given to carbonization of the as-prepared and mechanically activated precursors due to reaction with atmospheric carbon dioxide and their decarbonization in the course of calcination. The removal of the volatile components (H2O and CO2) from the as-prepared and mechanically activated precursors can be achieved by calcination at 1100–1200 °C for 3 h. Calcination of the as-prepared and mechanically activated precursors in the range of 700–1200 °C results in the formation of nanocrystalline fluorite-type Gd2Zr2O7. Gadolinium zirconate prepared from the mechanically activated precursor exhibits 4–9 times larger BET surface area relative to that of Gd2Zr2O7 synthesized at the same calcination conditions from the as-prepared precursor. In particular, this is beneficial for preparation of nanostructured dense ceramic materials with enhanced properties.

Concentration of oxide ion vacancies and its ordering in crystalline lattices play an important role in the structural, optical and ionic transport properties of RE2O3–MO2 (RE (Rare earths), M = Ti, Zr, Hf) systems. Rarely investigated rare earth zirconate system, RE4Zr3O12 (RE = Dy, Y, Er, and Yb) exhibiting the polymorphic structural forms, was chosen for the present study. RE4Zr3O12 nanoceramics were prepared through an auto-ignited combustion method; thereafter, dense bulk ceramics were derived from them at relatively low temperatures. X-ray diffraction studies carried out on the nanoceramics as well as bulk ceramics suggest defect fluorite structure for RE = Dy, Y and Er whereas δ-phase rhombohedral structure for RE = Yb ceramics. Extent of oxide ion ordering and the structural variations due to the replacement of rare earth ions in the crystalline lattices were analyzed by Raman and infrared spectroscopy. UV–Visible and photoluminescence spectroscopy were employed to investigate the optical properties of the nanoceramics. Impedance spectroscopic studies carried out on the bulk ceramic materials show that the oxide ion hopping conduction mechanism in the bulk ceramics was affected by the structural factors and free mobile oxide ion concentration. Increase of total electrical conductivity of the dense ceramics with the increase of temperature was in accordance with the Arrhenius relation. Electrical conductivity of fluorites was higher than the δ-phase ceramics, which was attributed to the decreased activation energy and increased available number of mobile oxide ions in the fluorite structure.

Ternary oxide powders based on titania, zirconia and silica have been synthesized by the sol–gel method. The characterization of the powders was performed using UV–Vis spectroscopy, EPR, X-ray diffraction and Raman spectroscopy. The XRD study indicated the formation of TiO2 nanocrystals in anatase phase and titanium zirconate as srilankite phase. The band gap energy values of ternary powders are in the range of 3.2–3.3 eV. It is found that different types of paramagnetic centers were formed depending on silica sources after high-energy irradiation. As shown by the electron paramagnetic resonance study, the stability of SiO2 against β-irradiation is observed only for TiO2/ZrO2/SiO2 powder obtained from tetraethoxysilane as well as the formation of oxygen vacancies in TiO2 structure. Photocatalytic activity of TiO2/ZrO2/SiO2 powders is investigated in the process of photoreduction of Cr(VI) ions to Cr(III). As shown, the efficiency of photocatalyst depended on the nature of defect sites of the nanocomposites’ surface. It is found that the TiO2/ZrO2/SiO2 system obtained using tetraethoxysilane exhibited the highest photocatalytic activity as a result of the certain defect sites formation after high-energy irradiation.

Technology is suggested for fabrication of ceramic piezoelectric materials from the lead-containing ferroelectric phase. The technology includes a low-temperature synthesis of ultradispersed lead titanate and zirconate powders and also of phases of solid solutions on their basis and the low-temperature procedure for sintering of ceramic fabricated from ultradispersed powders of ferroelectric phases. As precursors used in the suggested low-temperature synthesis serve lead glycerate and tartrate. It was found that, when interacting (at temperatures of 240–330°C) with hydroxo-peroxo-aqua complexes of titanium and(or) zirconium(IV) in the course of 30–40 min, the precursors form ultradispersed powders of these phases, which are single-phase and contain particles with average size of less than 100 nm. It was shown that using the suggested technology makes it possible not only to reduce the energy expenditure for separate procedures for synthesis of ultradispersed ferroelectric phases and for synthesis of piezoelectric materials, but also to substantially diminish the discharge of lead(II) compounds into the atmosphere of industrial premises. It was also shown that the technology enables fabrication of piezoelectric materials with prescribed values of electrical parameters.

Zirconium and hafnium compounds are widely used in today’s technology. Zirconium or hafnium carbides and borides are high temperature ceramics.The present study concerns primarily with optimizing the extraction of zirconium and hafnium from their naturally occurring mineral, zircon, via a wet chemical process. First , zircon heated with molten sodium hydroxide to form zironate and silicate frit. Simple separation technique of sodium silicate from the zirconate and hafnate sodium was then applied to obtain a silicate-free frit, then the extraction of the zirconium ( IV ) and hafnium ( IV ) basic sulfates from their oxychloride solution leaving almost all other ions soluble in the mother liquor was achieved by adjusting the pH value. The precipitate of zirconium ( IV ) and hafnium ( IV ) basic sulfates was dried, weighed, analyzed and percent of the zirconium and hafnium extracted were found to be 97 % of their original concentration.

Nowadays, the contribution of rare-earth oxide compounds is extensively investigated with the aim to improve the service life of gas turbine engine components protected by thermal barrier coatings (TBCs) against the environmental Calcia-Magnesia-Alumino-Silicate (CMAS) attack. Therefore, the TBCs consisting of a NiCrAlY bond coat, Yttria Stabilized Zirconia (YSZ) and/or mixture of YSZ and Gadolinium Zirconate (YSZ+GZ) interlayers, and a GZ top coat, which were all deposited by atmospheric plasma spraying onto the nickel-based superalloy substrates, are introduced in this contribution. The CMAS-attack resistance was evaluated using an indirect method. Firstly, the thin layer of CMAS prepared from colloidal solutions was deposited onto the top coat surface and, after drying, the samples were heat treated with the aim to glassified the CMAS. Secondly, the coated samples containing CMAS glass debris were subjected to rapid heating (up to 1200 °C) and enforced cooling cycles at the burner-rig test device and the failure of TBC was investigated. In all cases, the failure mechanism due to the CMAS attack was the top coat spallation. The functional graded TBC was found to be the most resistant system.

A metal-ferroelectric-metal (MFM) capacitor was fabricated to investigate the effect of the rate-of-change of temperature in the rapid thermal annealing (RTA) process on the physical properties of the MFM capacitor’s ferroelectric layer [lead zirconate oxide (PZT)]. Remnant polarization (2 × Pr) is measured and monitored while performing the RTA process at 500 °C–700 °C. It turned out that, for a given target/final temperature in the RTA process, 2Pr of the ferroelectric layer decreases with a higher rate-of-change of temperature. This can provide a way to adjust the properties of the PZT layer, depending on the RTA process condition (i.e., using various rate-of-changes of temperature) for a given final/target temperature.

International audience; Three long-term experiments have been performed in SOEC and SOFC modes at different operating temperatures. The durability tests confirm a higher degradation in electrolysis mode with respect to fuel cell operation. In addition, a larger increase of the ohmic resistance is observed for the cell operated at higher temperature in electrolysis mode. The oxygen electrodes of the pristine and tested cells have been characterized by synchrotron X-ray micro-diffraction and micro-fluorescence to assess the relation between the material destabilization and the formation of insulating phases due to interlayer diffusion. The analyses of the pristine cell confirm the presence after the electrode sintering of strontium zirconate and a Gd-rich inter-diffusional layer in the electrolyte just below the zirconates. Moreover, evolutions in the LSCF unit cell volume reveal strontium segregation after aging. The associated material destabilization is linked to the accumulation of SrZrO 3 at the barrier layer-inter-diffusional layer interface in operation and both phenomena are found to be thermally-activated and promoted in electrolysis mode. Finally, the crystallographic evolution of the inter-diffusional layer in electrolysis mode has been investigated by X-ray diffraction. A slight increase of the phase peaks intensity detected at the highest temperature is correlated to the largest formation of SrZrO 3 observed in this condition. Based on these preliminary results, it is proposed that the loss of Zr 4+ from the electrolyte due to the zirconates formation could facilitate the inter-diffusion of Gd, reducing the local ionic conductivity and thus significantly contributing to the largest increase in the ohmic resistance observed in this case.

Kurşun zirkonat titanat (PZT) bazlı ferroelektrik seramik malzemeler ticari öneme sahip piezoelektrik malzemelerdir. Stronsiyum zirkonat titanat (SZT) perovskit malzemeleri de geniş bir uygulama alanına sahiptir. PZT ve SZT başlangıç çözeltileri uygun olan çeşitli yöntemler kullanılarak hazırlanabilir. Bu yöntemler arasında sol-jel işlemi, düşük sıcaklık gereksinimi, homojenlik ve uygun partikül boyutunun elde edilebilmesi nedeniyle özel ilgi görmüştür. Elektroeğirme yöntemi nanofiber üretiminde en etkin ve en yaygın kullanılan yöntemdir. Elektroeğirme, katı ve boşluklu içyapılı, uzun boylarda, homojen çapta ve çeşitli bileşimlerde nanofiber üretimi sağlayan bir yöntemdir. Elektroeğirme teknolojisi sol-jel yöntemi ile birleştirildiğinde, polimer veya seramik çözeltiden belirli bir elektrik alan altında sürekli nanofiber, nanotüp ve dolgulu nanofiber üretimi gerçekleşmektedir.Bu çalışmada, Sr ve Pb içeren kurşun zirkonat titanat (PZT) ve stronsiyum zirkonat titanat (SZT) çözeltileri sol-jel yöntemi ile hazırlanmıştır. Çözeltiler, öncü malzemeler olarak metal tuzları ve alkoksitler kullanılarak hazırlanmıştır. Elde edilmiş olan Çözeltiler, 1.6, 1.8, 2.0 mL / saat akış hızlarında beslenmiştir ve 20 kV voltaj değerinde PZT ve SZT nanofiberleri elektrospinning yöntemi ile oluşturulmuştur. Elektroeğirme cihazının farklı parametreleri incelenmiş ve SZT ve PZT nanofiberleri optimum özelliklerde üretilmiştir. Üretilen nanofiberlerin kristal yapısı, morfolojik yüzey karakterizasyonu ve kimyasal özellikleri sırasıyla XRD, SEM ve EDX ile yapılmıştır. XRD sonuçları Sol-jel ve elektrospinning işlemleri sırasında PZT ve SZT'nin perovskit yapısının bozulmadığını göstermiştir. PZT ve SZT nanofiberlerin SEM analizlerinde az miktarda boncuksu yapı gözlemlenmiştir. Nanofiberlerin EDX analizine göre PZT ve SZT yapısının da oluştuğu görülmüştür., Lead zirconate titanate (PZT)-based ferroelectric ceramic materials are piezoelectric materials of commercial importance. Strontium zirconate titanate (SZT) perovskite materials also have a wide application area. PZ and SZT starting solutions can be prepared using a variety of suitable methods. Among these methods, the sol-gel process has attracted special attention due to the low temperature requirement, homogeneity and the ability to obtain the appropriate particle size. The electrospinning method is the most effective and widely used method in nanofiber production. Electro-spinning is a method that enables the production of solid and hollow nanofibers in long lengths, homogeneous diameters and various compositions. When the electro-spinning technology is combined with the sol-gel method, continuous nanofibers, nanotubes and filled nanofibers are produced from polymer or ceramic solution under a certain electric field.In this study, lead zirconate titanate (PZT) and strontium zirconate titanate (SZT) solutions containing Sr and Pb were prepared by sol-gel method. Solutions were prepared using metal salts and alkoxides as the precursor materials. The solutions obtained were fed at flow rates of 1.6, 1.8, 2.0 mL / hour and PZT and SZT nanofibers were formed by electrospinning method at 20 kV voltage rating. Different parameters of the electrospinning device were examined and the SZT and PZT nanofibers were produced with optimum properties. Crystal structure, characterization of morphological surface and chemical properties of the produced nanofibers were done with XRD, SEM and EDX, respectively. XRD results showed that the perovskite structure of PZT and SZT was not damaged during Sol-gel and electrospinning processes. A small amount of beady structure was observed in SEM analysis of PZT and SZT nanofibers. According to EDX analysis of nanofibers, it was observed that the PZT and SZT structure was also formed.

The aim of this work is to develop an effective catalyst for the conversion of butanediols, which is derivable from biomass, to valuable chemicals such as unsaturated alcohols. The dehydration of 1,4-, 1,3-, and 2,3-butanediol to form unsaturated alcohols such as 3-buten-1-ol, 2-buten-1-ol, and 3-buten-2-ol was studied in a vapor-phase flow reactor over sixteen rare earth zirconate catalysts at 325 &deg, C. Rare earth zirconates with high crystallinity and high specific surface area were prepared in a hydrothermal treatment of co-precipitated hydroxide. Zirconates with heavy rare earth metals, especially Y2Zr2O7 with an oxygen-defected fluorite structure, showed high catalytic performance of selective dehydration of 1,4-butanediol to 3-buten-1-ol and also of 1,3-butanediol to form 3-buten-2-ol and 2-buten-1-ol, while the zirconate catalysts were less active in the dehydration of 2,3-butanediol. The calcination of Y2Zr2O7 significantly affected the catalytic activity of the dehydration of 1,4-butanediol: a calcination temperature of Y2Zr2O7 at 900 &deg, C or higher was efficient for selective formation of unsaturated alcohols. Y2Zr2O7 with high crystallinity exhibits the highest productivity of 3-buten-1-ol from 1,4-butanediol at 325 &deg, C.

Various types of fuels were used in a low-temperature solution combustion synthesis of zinc zirconate nanocomposite at a pH of 7. In the synthesis, the fuels used were citric acid, glycine, urea, hydrazine hydrate, and ammonium nitrate while zirconium butoxide and zinc nitrate were the precursor sources of Zr4+ and Zn2+ ions, respectively. The samples were calcined for 2 h at a temperature of 600 °C. The study of the structural properties showed varied morphologies ranging from highly agglomerated surfaces, crystalline aggregates as well as nanorods. There was a gradual growth of zinc zirconate perovskite within phases of zirconia and zinc oxide. It was observed that there were prominent photoluminescence emissions spread from violet-blue into the yellow-white regions with peaks varying from about 400 to 490 nm. The energy bandgap of the nanocomposites was between 2.93 and 3.22 eV depending on the fuel used in the preparation of the sample.

A wide range of magnetoelectric composites has been prepared: (100 − x) wt% FE + x wt% YIG (x = 30–70 in steps of 10 wt%), where YIG is yttrium iron garnet and FE is a lead-free ferroelectric material reported in the literature, namely lithium sodium potassium niobate ([Li0.06(Na0.52K0.48)]1.04NbO3, KLNN), modified sodium bismuth titanate ([96 mol.% Bi0.5(Na0.84K0.16)0.5TiO3 + 4 mol.% SrTiO3 + 0.2 wt% La2O3], BNT) or barium calcium zirconate titanate (Ba0.85Ca0.15Ti0.9Zr0.1O3, BCZT). The interfacial reactions and dielectric, piezoelectric, magnetic and magnetoelectric behaviors of the composites have been studied. The high-temperature calcination was found to yield the fergusonite-type impurity phase YNbO4 in KLNN-containing composites and the pyrochlore-like phase Y2Ti2O7 in BNT-containing ones. The BCZT-containing samples remain the only phase-pure materials after heat treatment. As a result, among the materials studied, the samples of (100 − x) wt% BCZT + x wt% YIG show the best magnetoelectric coupling coefficient ΔE/ΔH that reaches ~ 5 mV/(cm Oe) with x = 40. Despite showing significant piezoelectric response, the KLNN-containing ceramics exhibit ΔE/ΔH of 1.2 mV/(cm Oe) or less. The composites containing BNT show weak piezoelectric and almost zero ME response (ΔE/ΔH does not exceed 0.2 mV/(cm Oe)) due to the decomposition of ferroelectric phase caused by high-temperature interfacial reactions. The BCZT-containing composites appeared to be magnetically softer than KLNN-containing materials and magnetically harder than BNT-containing ones.

Zirconate systems having the composition 3HfO2·15SiO2·xY2O3·(82 − x)ZrO2, where x = 2, 7 and 12 mol% Y2O3, were synthesized by a sol-gel method. The analysis of X-ray diffraction data showed the presence of the t-ZrO2, m-ZrO2, m-HfO2, Y2SiO5 and Y2Si2O7 crystalline phases in a ceramic nanomixture. Spectroscopic data show that the increase of the Y2O3 content of samples determines the increase of the t-ZrO2, m-HfO2 and silicate crystalline phases. Gap energy values decrease almost linearly with increasing Y2O3 content of samples. A detailed study of XANES data does not show a significant difference with increasing Y2O3 content of the samples suggesting an appreciable stability of the hafnium ions +4 oxidation state and their microvicinity. EXAFS results show that the local structure around the Hf cation is similar to that from the monoclinic crystalline HfO2 where the Hf–O coordination number tends to 7. The bond lengths of Hf–O shells show small deviations from ∼2.12 Å and the Hf–metal paths become more structured by increasing the Y2O3 content of the samples.

Highly ordered nanoscale disc-like cubic gadolinium doped magnesium zirconate (Gd:MgZrO3) was synthesized by facile solvothermal route. The reaction time was found to be crucial in determining the final morphology of disc-like Gd:MgZrO3. After studying the particles from time-dependent experiments, it is observed that, the formation of disc-like particles involved a complex process, in which rod-like or agglomerate particles were favorably formed after the initial thermal treatment. Owing to the chemical instability, they would turn into disc-like particles. After calcination, the generated product possessed good photocatalytic performance for the degradation of Rhodamine B (50 mg l−1) under UV light irradiation in contrast to morphologies of Gd:MgZrO3 and other related state-of-the-art photocatalysts (e.g., TiO2, ZnO, WO3, BiVO4, Fe2O3, and g-C3N4). The catalyst could be used for five cycles, maintaining its efficiency above 94.2%. These capacities made the disc-like Gd:MgZrO3 a potential candidate for polluted water treatment. Also, the underlying photocatalysis mechanism of Gd:MgZrO3 was proposed through radical trapping experiments.

The structural and electrical physical properties of barium titanate zirconate thin films on pure sapphire substrates and sapphire substrates with a platinum sublayer are investigated. The nature of substrate is shown to have a considerable effect on the crystal structure, phase composition, and electrical parameters of the prepared thin films. Capacitive elements fabricated using barium zirconate titanate films display high nonlinearity at low dielectric losses, as measured at a frequency of 2 GHz.

Zirconium (Zr) based bioceramic nanoparticles, as the filler material to chitosan (CS), for the development of composite scaffolds are less studied compared to hydroxyapatite nanoparticles. This is predominantly due to the biological similarity of nano-hydroxyapatite (nHA; Ca(10)(PO(4))(6)(OH)(2)) with bone inorganic component. In this study, we compared the physical and biological properties of CS composite scaffolds hybridized with nHA, nano-zirconia (nZrO; ZrO(2)), and nano-calcium zirconate (nCZ; CaZrO(3)). For the first time in this study, the properties of CS-nCZ composite scaffolds have been reported. The porous composite scaffolds were developed using the freeze-drying technique. The compressive strength and modulus were in the range of 50–55 KPa and 0.75–0.95 MPa for composite scaffolds, significantly higher (p

We have prepared magnetoelectric (ME) composite ceramics, free of foreign phases, in the lead zirconate titanate–cobalt nickel ferrite two-phase system: xPZT-36 + (100–x)Ni0.9Co0.1Fe2O4. The sol–gel derived ferrite powder used in our preparations seems to be doped with titanium cations from the PZT-36. The ceramics have a percolation threshold at x = 50–70 wt %, which is due to the increased electrical conductivity of Ni0.9Co0.1Fe2O4. As a consequence, the piezoelectric parameters of the ME ceramics drop sharply at x < 50–70 wt %: the piezoelectric moduli |dij| and piezoelectric voltage coefficients |gij| decrease by a factor of 3–5 in this composite range. The piezoelectric parameters |dij| and |gij| of the composites produced using the fine ferrite powder exceed those of the materials prepared using macrocrystalline Ni0.9Co0.1Fe2O4 powder by more than a factor of 2. The piezoelectric voltage coefficient g33 correlates with the ME coefficient ΔE/ΔH. The highest ME conversion efficiency (up to 45 mV/(cm Oe)) is offered by the 80 wt % PZT-36 + 20 wt % Ni0.9Co0.1Fe2O4 composites, whose composition lies in a subpercolation region. Even though the composites produced using the fine ferrite powder possess improved piezoelectric properties, they have smaller ΔE/ΔH coefficients (no greater than 25 mV/(cm Oe)), which can be tentatively attributed to the degradation of the properties of the ferrite as a consequence of doping with Ti4+ cations during the sintering of the composite ceramics.

The present paper analysed the formation of calcium zirconate from zirconium dioxide and calcium hydroxide through solid state reaction. Different mole ratios and sintering temperatures are investigated. The sintering temperature was reduced to 1200 °C. Due to the decomposition process of the calcia source during firing the volume expansion in the sintered samples was remarkable. A good homogenisation of the raw mixture is necessary to obtain a complete reaction of the material. The microstructure of the calcium zirconate gained from calcium hydroxide and from calcium carbonate did not differ. Moreover, a difference in reactivity due to varying microstructure and temperature of decomposition between the different calcia sources could not be determined. Thus calcium carbonate is less hazardous and resulted in a higher yield of calcium zirconate compared to calcium hydroxide as calcia source.

Highly flexible biocompatible nanocomposites comprising of Polyvinylpyrrolidone (PVP) modified Barium Calcium Zirconate Titanate (BCT-BZT) /Polyvinylidene fluoride (PVDF) were fabricated. The crystalline BCT-BZT powders were synthesized by a simple sol-gel method. Rietveld refinement analysis confirmed the coexistence of orthorhombic and tetragonal phase in the synthesized powders. The structural, dielectric and ferroelectric properties of the composites were analysed. Addition of PVP modified BCT-BZT powders was observed to enhance the polar phase in PVDF matrix. The piezoelectric output response as a function of different weight percentage of ceramic powders in the PVDF matrix was investigated. The optimal device with 60 wt% PVP modified BCT-BZT powders exhibited maximum peak to peak voltage of 23 V when tested for harnessing waste biomechanical energy (human hand palm force). The nanogenerator was easily scaled up to 4 × 4 cm and the stored power was utilized for powering fifty five LEDs. The fabricated device is flexible, light- weight and eco-friendly. Therefore, it can be explored as a potential candidate for application as self powered sensor.

Calcium zirconate (CaZrO3) is a promising refractory material to melt titanium alloys. Therefore the present study investigated refractory castables based on CaZrO3 to allow an upscaling to larger melting crucibles and refractory linings. The study first included the processing optimization of the refractory castable containing calcium aluminate cement using a full factorial experimental design. Then the physical, chemical, mechanical and thermomechanical properties that determine the practical application of the castable were analyzed. The properties were generally similar to the ones of uniaxially pressed refractories based on CaZrO3. Nevertheless, the matrix containing calcium aluminates caused a pronounced sintering shrinkage leading to a smaller apparent porosity and a lower refractoriness compared to uniaxially pressed refractories. Finally, melting crucibles with an inner volume of 900 ml were successfully manufactured. Thus, this study provides an effective framework for the further development of large CaZrO3 refractories. Keywords: Refractories, Calcium zirconate, Titanium alloys, Castables, Calcium aluminate cement, Thermomechanical properties

In this work, electric field-induced strain behavior and ferroelectric properties of xBCZT/PZT (with x = 0, 4 and 8 mol%) ceramics have been investigated. The Ec and Pr increased with increasing electric field and exhibited pinched-shape hysteresis loop at 60 kV/cm. The abnormal domain walls and switching behavior of the domains were used to discuss the above results. The strain value increased with increasing BCZT content and reached the maximum value of 0.27% (d*33 = 450 pm/V) for the 4 mol% BCZT sample. This offered an opportunity to obtain a good candidate for using in piezoelectric applications.

Lead free Sodium Bismuth Titanate Zirconate (Na0.2Bi0.3Zr0.5) TiO2 or NBZT Solid solution were prepared by Mixed Oxide Conventional route. Moreover, their Phase Structure and luminescence properties were investigated for storage device applications. Primarily XRD analysis indicated that mixed phase structure at the higher annealing temperature. X ray powder Diffraction Data were used for a quantitative Structural investigation. SEM results for spherical and cuboid particles were observed. Based on results we can say that average grain diameter for NBZT is around 100-200 nm. Ferroelectrics perovskites has optical properties, which is shown in photo luminescence emission and absorption Spectra. Photoluminescence arises when excited by photon so in this present work excitation band at 390 nm (3.2 eV).we say that hard and soft Ferro electric ceramics. Peaks are observed between 2.76 eV to 4.10 eV from the emission spectra. Absorption spectra are used for excitation wavelength.

The structure of tetra­lithium octa­fluorido­zirconate has been redetermined by high-resolution single-crystal X-ray diffraction. This result is largely consistent with a prior report, but with significant improvements in precision., Presented herein is the crystal-structure redetermination of Li4ZrF8 from single-crystal X-ray data. Alkali zirconium fluorides are important in nuclear-relevant technologies, and zirconium is commonly employed as an analogue for tetra­valent f-block elements. The previous structure report of this species is based on powder X-ray data [Dugat et al. (1995 ▸). J. Solid State Chem. 120, 187–196] but there has never been a refined structure model from single-crystal data. The octa­fluorido­zirconate moieties are held together by electrostatic attraction to lithium ions without sharing of fluoride sites between zirconium(IV) ions.

Cobalt Zirconate/g-C3N4 hybrids (Co2ZrO5/g-C3N4) are synthesized with different mass ratios of g-C3N4 using hydrothermal and grinding methods. In the present research, the physicochemical properties of the synthesized composites are studied. The effects of changing surface area, pore diameter, and bandgap change are checked using BET and DRS. Characterization results for Co2ZrO5/g-C3N4 indicate that two different synthesis methods have various effects on the crystal structure and morphology leading to different photocatalytic performances. Furthermore, the synthesis of Co2ZrO5/MWCNTs and Co2ZrO5/MCM-41 is successfully performed. Co2ZrO5 NPs do not degrade rhodamine B. Also, they have a poor performance at high concentration of methylene blue under visible radiation. In this study, it has been demonstrated that the modification of MCM-41, g-C3N4, and MWCNTs surfaces by Co2ZrO5 NPs significantly improves their photocatalytic behavior, so that the degradation efficiencies are increased up to more than 99%, 90%, and 91% for Co2ZrO5/g-C3N4 hybrid, Co2ZrO5/MCM-41, and Co2ZrO5/MWCNTs, respectively. Consequently, the possible mechanism of the degradation process and the cause of the difference in the photocatalytic behavior of composites are discussed.

Dispersion of petite quantity (Mg1−xCexZryO3) of cerium dopant in the lattice of magnesium zirconate (MgZrO3) is an efficient strategy to stimulate solar light photocatalytic activity of the material and achieve superior charge carrier separation. In this research, we demonstrate the tailoring of MgZrO3 to become a solar light sensitive material for the degradation of methyl orange (MO) dye and hydrogen evolution from water. Cerium doped MgZrO3 nanocubes (Mg1−xCexZryO3NCs) showed 93% efficiency for the degradation of MO and was able to show a maximum hydrogen evolution rate of 13,318 µmol h−1 g−1. It was found that, concentration of cerium plays a key role in the overall performance of the photocatalyst. A systematic characterization by Brunauer–Emmett–Teller (BET), Scavenger experiments, Electron Spin Resonance Spectroscopy (ESR), Photoluminescence (PL) and photocurrent measurements of the Mg1−xCexZryO3 NCs showed that, it possesses high surface area, promotes transfer of photo-stimulated electrons and provides rich photo-active centers for the enhanced photocatalytic redox activity. Retention of structure and morphology even after rigorous cycling of the catalyst with respect to MO degradation and hydrogen evolution makes Mg1−xCexZryO3 NCs a robust photocatalytic material.

This paper reports our development of protonic ceramic fuel cells (PCFCs) with BaZr0.8Yb0.2O3−δ (BZYb) electrolyte. Although PCFCs can theoretically achieve ultra-high energy-conversion efficiency for power generation, higher power density even at lower temperatures below 600°C is required to widespread application. Here, a zirconate-based oxide of BZYb was selected as electrolyte material of PCFCs because of its high chemical stability against CO2. Also, cost-effective conventional wet processes were used to fabricate the PCFCs. High-temperature co-sintering successfully produced a dense and thin BZYb electrolyte. The PCFC showed a stable operation for 400 h without significant degradation. Investigation into changing parameters of large-size PCFCs (50 × 50 mm) such as anode porosity, interlayer function, electrolyte thickness, and cathode material improved the power density of the PCFCs with BZYb electrolyte. At 600°C, the power density reached 0.38 and 0.48 W cm−2 at 0.85 and 0.75 V, respectively.

Some of the solid oxide materials, used in solid oxide fuel and electrolysis cells, are known to conduct protons once they are hydrated. However, the mechanisms by which solid oxide materials get hydrated is not clear. By performing detailed density functional theory calculations, we investigate hydration of two typical solid oxides with a single-crystal structure—a proton-conducting yttrium-doped strontium zirconate (SZY) and an oxide ion-conducting yttria-stabilized zirconia (YSZ). We suggest a four-step process to understand the hydration of solid oxides—water adsorption on the surface, proton migration from the surface to bulk, proton migration in the bulk, and oxide ion vacancy migration in the bulk. The hydroxide ion migration with a lower energy barrier, compared to the proton hopping mechanism, is proposed for the conduction of proton between the surface and subsurface of the perovskite oxide. Our analysis provides mechanistic insights into the hydration of single-crystal SZY and nonhydration of s...

This work highlights the possibility of the application of YBaCo4O7+δ-modified materials as cathodes for solid oxide fuel cells based on protonic electrolytes. To reach this goal, the basic YBaCo4O7+δ oxide material and its YBaCo3.5Zn0.5O7+δ (YBCZ) and YBaCo3.5Fe0.5O7+δ (YBCF) substituted members were successfully synthesized and their structural, thermal and electrochemical properties were evaluated for their suitability for application. It was found that the substitution of cobalt with zinc results in the structural stabilization of such “114” phases and the convergence of the thermal expansion coefficient with that of the selected BaCe0.5Zr0.3Dy0.2O3–δ (BCZD) electrolyte as well as superior electrochemical activity below 700 °C. The Ni-BCZD|BCZD|YBCZ cell yields relatively high power density (200 mW cm–2 at 600 °C) and exhibits low polarization resistance (0.51 Ω cm2 at 600 °C). This, combined with the low activation energy values found for electrode polarization conductivity of both symmetrical and fuel cells allow assuming that the Zn-substituted YBaCo4O7+δ material could be successfully used in electrochemical devices based on proton-conducting electrolytes.

A simple route has been successfully developed to prepare pure neodymium zirconate nanostructures with high photocatalytic efficient. Neodymium zirconate has been prepared utilizing maleic acid as new stabilization agent. The effects of the type and dosage of esterification agent and space-filling template kind on the shape, particle size and photocatalytic activity of neodymium zirconate were investigated. It is found that these factors play effective roles in controlling the shape, size and photocatalytic activity of neodymium zirconate. The obtained neodymium zirconate was characterized by Fourier transform infrared (FT-IR) spectroscopy, UV–vis diffuse reflectance spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy and energy dispersive X-ray microanalysis (EDX). To compare the catalytic characteristics of the formed neodymium zirconate samples, the photocatalytic degradation of eosin Y contaminant was carried out.

A modification of a solution method for preparing solid oxide electrolyte films was developed. It is based on using a suspension consisting of a solution of inorganic salts and of a nanodispersed precursor powder prepared from the same solution. As demonstrated by the example of calcium zirconate, this procedure allows the number of applications of the liquid-phase precursor, required to obtain a dense electrolyte film on a porous support, to be considerably decreased relative to the procedure using a salt solution. The influence of the concentration of the precursor powder in the suspension on the microstructure of CaZr0.9Y0.1O3–δ films was analyzed.

Alkaline earth titanates and zirconates and their binary systems are of interest for their temperature in sensitive dielectric properties. Calcium titanate and calcium zirconate perovskite ceramics find applications in pulse discharge, energy storage and microwave capacitors. These dielectric materials have been used in electric hybrid and fuel cell vehicles. In the present work, fine crystalline compound powders of calcium titanate and calcium zirconate were prepared by a single step molten salt synthesis. Calcium oxide and titanium dioxide/zirconium oxide were used as precursors to obtain the calcium titanate and calcium zirconate compound powders respectively. The prepared calcium titanate and calcium zirconate compound powders were characterized by TGA, FTIR, XRD, SEM and EDS analysis.

Nd2Zr2O7 (neodymium zirconate) nanostructures have been successfully prepared by a modified Pechini approach utilizing succinic acid as novel stabilization agent and propane-1,2-diol as new cross-linking agent in presence of tetraethylenepentamine as novel pH regulator and co-capping agent. Type of pH regulator and propane-1,2-diol dosage have been changed to study the influence of preparation factors on the shape and size of neodymium zirconate. The obtained neodymium zirconate was characterized by Fourier transform infrared (FT-IR) spectroscopy, UV–vis diffuse reflectance spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy and energy dispersive X-ray microanalysis (EDX). To examine the catalytic characteristics of the obtained neodymium zirconate, the photocatalytic degradation of erythrosine and eriochrome black T dyes under ultraviolet illumination were performed.

Zirconia-stabilized Ca-based sorbent has been previously investigated for cyclic CO 2 capture processes; however, the cost of pure zirconia may be a matter of concern. The cost of sorbent can be decreased by addition of a low cost second metal oxide with zirconia-stabilized Ca-based sorbent. This study examined a number of mixed metal oxides supports, such as alumina, silica, titania, magnesia and molybdena, with zirconia (ZrO 2 ) for stabilization of calcium (Ca) based sorbents directly produced from a co-precipitation method. Selected metal oxide supports (i.e. alumina and silica) are commonly used in catalytic steam gasification. The proposed novel strategy aimed at enhancing sorbent stability, increasing surface area, decreasing cost of zirconia-stabilized sorbents and investigating the effects of the common used supports in catalytic steam gasification on the performance of Ca-based sorbents. The optimal composition for the activity of ceramic-stabilized calcium oxide (CaO) samples under mild operating conditions was determined to be 10 wt.% ceramic incorporated in the sorbent. The results indicated considerable sorbent stability and capacity improvement for mixed metal oxide zirconia-stabilized CaO over those of pure CaO, which showed significant cyclic capacity decay under similar conditions. Among the studied materials, aluminum zirconate, calcium zirconate, and zirconium molybdate stabilized sorbents showed the best initial uptake and performances in severe operating conditions over 60 cycles. However, titania, silica and magnesia supports showed negative effect on the sorbent performance.

Fabrication of piezoelectric composites with 3-3 connectivity and their properties have attracted attention due to the application of these composites in acoustic transducers, medical imaging, and nondestructive testing. In this research, directional piezoelectric-polymer composites with 3-3 connectivity are prepared by a relatively simple fabrication process of dipping an ordered polymeric template (mesh) into lead zirconate titanate suspension followed by drying, pyrolysis, and sintering. The resulting porous ordered structures of lead zirconate titanate-5A ranging from 18 to 32 vol% ceramic were subjected to polymer injection to form composites to be cut and polarized in different directions. In the composites, the effects of (i) polarization direction and (ii) active piezoelectric phase content on the dielectric and piezoelectric properties were investigated. The results showed that the dielectric constant and the piezoelectric properties are significantly dependent on the direction in composites of directional structure. In these composites, dielectric constant values were found to be higher in the direction parallel to ceramic ligaments. Moreover, the highest values for piezoelectric charge and voltage coefficient and figure of merit were found in the direction 45° to ceramic ligaments. In all composites, both dielectric constant and piezoelectric property values were proportional to the active piezoelectric phase content.

Zinc zirconate nanocomposite was synthesized by a low-temperature solution combustion method using citric acid as fuel at a pH of 7. The synthesis was done by varying the ratios of zirconium butoxide and zinc nitrate, which were the precursors in this study. The samples were calcined at 600 °C for 2 h then their structural and optical characteristics investigated. The analysis showed that the nanocomposite consisted of mixed phases of zinc zirconate, zinc oxide, and zirconium oxide. As the Zn2+/Zr4+ ratio increased, the highly agglomerated morphologies gradually developed crystalline aggregates mixed with nanorods. A red-shifted blue emission with a peak at 409 nm was observed in the photoluminescence spectra and the composites had an energy bandgap between 2.81 and 3.12 eV., Materials chemistry, Materials science, Nanotechnology, Nanocomposite; Zinc zirconate; Solution combustion synthesis; Perovskite; Zirconium butoxide