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In this study, high-temperature composite materials based on reactively sintered silicon carbide modified with a molybdenum bond are obtained. The microstructure, phase composition, and physico-mechanical properties of the formed composites are determined. It is experimentally shown that molybdenum in the process of reaction sintering forms a stable MoSi2 phase with a silicon melt in the volume of the sintered ceramic material. It is shown that the numerical parameters of lacunarity and chaos allow us to evaluate the homogeneity of the material structure in a direct relationship with the variation of the technological modes of ceramic synthesis. The resulting composites are characterized by a density of about 3.02–3.16 g/cm3 and a bending strength of about 180–220 MPa. [ABSTRACT FROM AUTHOR]

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]