Microstructure and electrical properties of porous Y1−xCaxFeO3 cathode materials by gelcasting process

Porous Y1−xCaxFeO3 (YCF) ceramics were successfully fabricated by a gelcasting process followed by sintering the gelled mixture of Y2O3, CaCO3 and Fe2O3. A pure YCF ceramic was obtained when the gelcast with x≤0.10 was calcined at 1250 °C in air for 5 h. Results showed that the specimen with x=0.10 had the lowest porosity. This contributed to the formation of a solid solution, which might greatly facilitate the sintering process of specimens. The Y0.9Ca0.1FeO3 specimens calcined at 1200–1275 °C for 5 h have an open porosity of 66.2–16.4% and mean pore size of 1.91–0.69 μm. The electrical conductivity of the porous specimens was investigated by the DC four-probe method. The results showed that Ca2+ doping greatly improves the conductivity of YCF specimen and dramatically reduces the activation energy for conductivity.