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Finely dispersed mesoporous powders of the following composition are synthesized by the method of cocrystallization of nitrate salts with ultrasonic treatment: La1–xSrxNiO3–δ, La1–xSrxCoO3–δ, and La1–xSrxFe0.7Ni0.3O3–δ (x = 0.30; 0.40). Based on them, ceramic nanomaterials of the given composition with a coherent scattering region (CSR) of ~65–69 nm (1300°С) are obtained. Ceramics fired at 1300°C are single-phase and have a tetragonal and orthorhombic perovskite-type structure in the La2O3‒SrO‒Ni(Co,Fe)2O3–δ system. Solid solutions have mixed electron–ion conductivity with transfer numbers te = 0.98–0.90 and ti = 0.02–0.10. Ceramics with a tetragonal perovskite-type crystal structure exhibit higher electrical conductivity than materials having an orthorhombic perovskite-type crystal structure. According to their electrophysical properties related to the structural features of solid solutions, ceramic materials obtained based on them are promising as solid oxide cathodes for average-temperature fuel cells. [ABSTRACT FROM AUTHOR]

This article describes the production of nanodisperse xerogel and powders (average CSR size of 9 nm) in the ZrO2–Y2O3–Al2O3 system by coprecipitation of hydroxides. A strong highly porous ceramic has been produced from the initial powder with the composition of [(ZrO2)0.97(Y2O3)0.03]0.8(Al2O3)0.2 with pore forming additives using patented solid phase sintering. Using Doppler sonography, the volume of blood flow in arteriolas and capillaries has been estimated 150 and 250 days after implantation of plates. Therefore, the microcirculatory Doppler sonography seems to be a promising intravital method of estimating blood flow in the zone of plates from biocompatible nonresorbable material and, probably, inside the plates. It has been found that the ceramic plates based on zirconium dioxide in the body of experimental animals do not result in a negative reaction of animal's body. The in vivo experimental results make it possible to state that the obtained bioceramic based on zirconium dioxide is a promising material for endoprosthetics. [ABSTRACT FROM AUTHOR]

By the joint crystallization of solutions of nitrate salts, fine powders of La1 – xSrxNiO3, La1 ‒xSrx-CoO3, and La1 –xSrxFe0.7Ni0.3O3 (x = 0.30 and 0.40) are synthesized. They have a specific pore volume of 0.018–0.035 cm3/g and a specific surface area of 15–31 m2/g. On their basis, ceramic nanomaterials of a given composition with CSR ~ 64–70 nm (1300°С) are obtained. The physicochemical properties of the obtained ceramic are studied; it is revealed that the ceramic is a solid solution with open porosity in a range of 17–30% and a high value of the relative density of 94%. In terms of their physicochemical properties (open porosity, density, coefficient of thermal expansion), the obtained ceramic materials are promising as solid oxide cathodes for intermediate-temperature fuel cells. [ABSTRACT FROM AUTHOR]

Mesoporous nanosized aerogels, xerogels, and powders in the ZrO2–Y2O3–CeO2 and ZrO2‒Y2O3–Al2O3 systems have been obtained by liquid-phase synthesis methods. The thermolysis, phase composition, and textural features of the synthesized materials have been studied. It has been found that the predominance of Lewis acid sites (LASs) on the surface of their particles indicates its lower hydroxylation and, as a consequence, a lower degree of agglomeration of the obtained materials. [ABSTRACT FROM AUTHOR]

Nanocrystalline ceramic samples of the ZrO2–3 mol % Y2O3 composition with varying degrees of tetragonality c/a (1.4337 and 1.0425) are obtained. The process of the low-temperature degradation of ceramics is studied by the methods of X-ray phase analysis and electron microscopy. It is found that samples with a high degree of tetragonality are more resistant to the action of a humid environment, while the phase composition in the bulk of the samples remains practically unchanged and the transformation t-ZrO2 → m-ZrO2 occurs mainly in the surface layers without significantly affecting the mechanical properties of the ceramics. [ABSTRACT FROM AUTHOR]

(In2O3)0.95(SnO2)0.05, (TbOх)0.50(Y2O3)0.50, and (CeO2)0.80(Y2O3)0.20 single-phase cubic solid solution xerogels and nanocrystalline powders have been synthesized via coprecipitation of hydroxides. Using these powders as precursors, nanoscale film electroconductive materials on a corundum substrate have been produced by screen printing. The highest speed of sensor response to ozone is attributed to In0.95Sn0.05O1.5 films, reaching 8–10 s at a temperature of 473 K. (TbOх)0.50(Y2O3)0.50 thin film is found to be sensitive to changes in the concentrations of (CO + CO2) (the sensitivity coefficient S = 25.11) and ozone (S = 3.16–7.94). (CeO2)0.80(Y2O3)0.20 film exhibits a sensor response to (CO + CO2) (S = 3.10). This study opens up the prospects of using the obtained nanopowders and relevant thin films as materials for resistive gas sensors operating at oxygen pressures of 103–104 Pa. [ABSTRACT FROM AUTHOR]

A strong highly porous ceramic for endoprosthesis possessing open porosity and elasticity modulus values similar to those of bone tissue is prepared through the solid-phase sintering of specimens of the initial powders of the (ZrO2)0.97(Y2O3)0.03 and [(ZrO2)0.97(Y2O3)0.03]0.8(Al2O3)0.2 compositions with blowing agents. The dependence of the characteristics of the sintered ceramics on the composition of zirconium-containing powders and blowing agents is investigated. [ABSTRACT FROM AUTHOR]

Powders–precursors of a tetragonal solid solution based on partially stabilized zirconium dioxide (t-ZrO2) and aluminum-magnesium spinel (MgAl2O4) are synthesized using the method of the cocrystallization of solutions of nitrate salts from which nanocrystalline (<100 nm) composite materials are fabricated at 1400°C in the ZrO2(Y2O3)–MgAl2O4 system with an open porosity of 3%. The structure, physical–mechanical properties, and thermal stability of the nanocomposites are investigated. It is established that the introduction of MgAl2O4 into the matrix of the solid t-ZrO2 solution increases the thermal resistance of the ceramics under the thermal cycling conditions (20–1000°С). The effect of thermal cycling on the phase composition, hardness, and bending strength of the ceramics in the ZrO2(Y2O3)–MgAl2O4 system is investigated. [ABSTRACT FROM AUTHOR]

A highly dispersed powder (9–10 nm) based on a tetragonal solid solution of partially stabilized zirconia (t-ZrO2) was synthesized by coprecipitation of hydroxides from salt solutions. On the basis of this powder, nanocrystalline ceramic (grain size 60–70 nm) with high physicochemical and mechanical characteristics was obtained: degree of tetragonality c/a, 1.438–1.431; flexural strength, 900–1000 MPa; Vickers hardness, 13–14 GPa; crack resistance, 10–11 MPa m1/2. The ceramic implant obtained was placed into bodies of experimental animals. The response of soft tissues of experimental animals to the introduction of zirconia-based ceramic plates was investigated. The studies showed no toxic effect of the t-ZrO2-based ceramic implant on the tissues surrounding the implant and the organism of laboratory animals in the period from 30 to 195 days from the moment of implantation. The results of in vivo studies suggest that the obtained nanoscale bioceramic can be used in restorative dentistry and endoprosthetics as dental implants, endoprostheses, and bone fragments for transplantology. [ABSTRACT FROM AUTHOR]