Papers by Author: Yan An Wang

Abstract: GdSrCoO3-δ and Gd1-XSrXCoO3-δ (x=0.1~0.5) were synthesized using glycine-nitrate process (GNP). The formation process of perovskite phase and microstructure of powders were characterized using TG-DTA and XRD. All the powders with different doping amounts of Sr2+ on A-site were single-phase solid solutions, and the stable perovskite phase was formed completely after calcination at 1100°C. The crystal structures of the solid solutions transfer to a higher symmetrical perovskite.

Abstract: A citrate gel method was applied to synthesize Ce0.8Sm0.2O1.9 powders by using cerium and samarium nitrates as raw materials and citric acid as complexing agent. It was shown that Ce0.8Sm0.2O1.9 phase was formed when the decomposition of the dried gel completed at 500 °C. The crystallite size of the synthesized powders calcined at 500 °C for 2 h is 5-10 nm. The powders can be easily sintered in air to yield over 97 % relative density at 1250 °C, which is significantly lower than sintering temperature of over 1500°C required by the doped ceria powders prepared via conventional ceramic techniques.

Abstract: Titanium carbonitride powders were synthesized directly by a combustion synthesis process between titanium and carbon in a nitrogen atmosphere. The relationships between properties of the final product and the combustion reaction parameters were systematically investigated. Especially, the effects of nitrogen pressure on the phase formation and microstructure of the as-synthesized products were experimentally investigated. The reaction mechanism of Ti(C,N) was proposed through quench experiment, the variation of combustion temperature on time and thermodynamics analysis.