Effect of Liquid-Phase Synthesis Method of Nanopowders on Microstructure and Physicochemical Properties of Ceramics in CeO 2 –Sm 2 O 3 System

摘要

Nanopowders of the composition of (СeO_(2))_(1 –)_( x )(Sm_(2)O_(3))_( x )( x = 0.02, 0.05, 0.10, and 0.20) were synthesized by two methods of chemical liquid-phase synthesis: coprecipitation of hydroxides with freezing and co-crystallization of salts with an average CSR size of ~8–11 nm and S _(sp)= 40–83 m~(2)/g. On their basis, ceramic nanomaterials with a cubic crystal structure of the fluorite type, with a CSR of ~65–81 nm (1300°C), were obtained. The dependence of the phase composition, microstructure, and electric transport properties of the obtained samples on the content of Sm_(2)O_(3)in a solid solution based on CeO_(2)and the synthesis method is revealed. It is shown that, in the series (СeO_(2))_(1 –)_( x )(Sm_(2)O_(3))_( x )( x = 0.02, 0.05, 0.10, and 0.20), a solid solution of the composition (CeO_(2))_(0.80)(Sm_(2)O_(3))_(0.20)has the highest ionic conductivity σ_(700°C)= 2.7 × 10~(–2)S/cm. The resulting ceramic can be used as a solid electrolyte for intermediate-temperature fuel cells owing to its physical and chemical characteristics.