Preparation and characterization of SrFeCo0.5O3.25+δ by gelcasting

SrFeCo0.5O3.25+δ powders have been successfully synthesized from SrCO3, 2CoCO3·3Co(OH)2·xH2O and Fe2O3 based on using the principle of gelcasting. Thermal decomposition of the gelcasting powder was analyzed by differential thermal analysis and thermogravimetry. The crystal structure of the sintered body was investigated by X-ray diffraction. It was found that SrFeCo0.5O3.25+δ samples formed by sintering the gelcasting powder over 1000°C consist mainly of the perovskite phase SrFe1-xCoxO3-δ. Electrical conductivity was measured by a DC four-probe technique and oxygen permeation flux was measured by applying oxygen partial pressure difference to a 1.4 mm thick pellet. Both the electrical conductivity and oxygen permeation flux of the gelcasting samples were much higher than that of samples prepared by a traditional solid state reaction method. Though further work should be performed on the higher transfer velocity of electron and oxygen ion, experimental data shows that the gelcasting process is a promising technique for the preparation of mixed conducting SrFeCo0.5O3.25+δ.