Sintering behaviour of La_(1-x)Sr_xCo_(0.2)Fe_(0.8)O_(3-delta)(0.3 < = x < = 0.8) mixed conducting materials

摘要

The sintering behaviour of different materials within the system La_(1-x)Sr_xCo_(0.2)Fe_(0.8)O_(3-delta)(0.3 < = x < = 0.8) was investigated. Shrinkage curves were measured up to 1350 deg C using a vertical high-resolution dilatometer. The measurements showed that the influence of the heating rate on the shrinkage curves is negligible. Furthermore, the relative shrinkage increases with decreasing lanthanum content in the perovskite lattice at a constant sintering temperature. Sintering experiments showed that the influence of the sintering temperature on the microstructure and densification is more significant than the influence of the dwell time. Increasing the sintering temperature led to a higher densification even at low sintering dwell times. There seems to be no influence of the lanthanum content on the final sintering temperature and dwell time. Nevertheless, sintering at the highest sintering temperature led to the formation of cobalt oxide in case of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-delta) and La_(0.7)Sr_(0.3)Co_(0.2)Fe_(0.8)O_(3-delta)