关键词: 凝胶浇注法;Sm_(0.5)Sr_(0.5)Co_(1-x)Fe_xO_(3-δ)粉体;电导率;热膨胀系数

Abstract: Sm_(0.5)Sr_(0.5)Co_(1-x)Fe_xO_(3-δ)(SSCF,x=0～1.0)powders were prepared by a gel-casting method using corresponding carbonates and oxides as raw materials. Phase composition and morphology of the obtained powders was investigated. Density and porosity of the sintered SSCF samples were measured by the Archimedes method. The microstructure was observed by scanning electron microscope (SEM), and the electrical conductivity was tested by the four-probe method. Thermal expansion coefficient (TEC) and electrochemical performance of the SSCF materials were also studied. The results showed that superfine and well-dispersed SSCF powders with perovskite structure are obtained when the dried gels are calcined at temperature above 1000 ℃.The iron dosage and temperature have an obvious influence on the phase formation, the density and the pore characteristics of the SSCF samples. The doping of Fe effectively lowers the TEC of the Sm_(0.5)Sr_(0.5)CoO_(3-δ) materials. Electrical conductivity of the SSCF samples decreases with iron doping but all is above 100 S·cm~(-1) at 500～800 ℃. Furthermore, the Sm_(0.5)Sr_(0.5)Co_(1-x)Fe_xO_(3-δ) samples show high oxygen catalytic activities.