BaSnO3 fine powders from hydrothermal preparations

摘要: Abstract Attempts to prepare BaSnO3 by the hydrothermal method starting from SnO2·xH2O gel and Ba (OH)2 solution in teflonlined autoclaves at 150–260°C invariably lead formation of a hydrated phase, BaSn(OH)6·3H2O. On heating air or on releasing pressure situ ≈260°C, BaSN (OH)6·3H2O converts fine powder which involves an intermediate oxyhydroxide, BaSnO(OH)4. TEM studies show that particle size resulting ranges 0.2–0.6 μm. Solid solutions Ba(Ti, Sn) O3 were prepared (TiO2+SnO2)·xH2O mixed Ba(OH)2 solutions. Single-phase perovskite Sn)O3 was obtained up 35 atom % Sn. Above this composition, products are mixtures BaTiO3 (cubic) BaSn(OH)6·3H2O ≈260°C give rise BaTiO3+BaSnO3. Annealing 1000°C results monophasic Sn)O3, complete range Sn/Ti. Formation phase is attributed amphoteric nature stabilises Sn(OH)62− anions under higher H2O-pressures elevated temperatures. The sintering characteristics dielectric properties ceramics these powders presented.