Air sinterable LaCrO3 based ceramics

In recent years, there has been a increasing demand for materials with high electrical conductivity at elevated temperature. Such materials have applications in MHD generators, high temperature fuel cells and sensors. The perovskite-type oxides fuel cells and senors. The perovskite-type oxide LaBO3 (B = Cr,Mn,Ni,Co) have attracted considerable attention because of their high melting points and high electrical conductivities. However LaCrO3 even with dopants is difficult to sinter due to vapor phase transport of higher valent oxides of chromium. Typically, sintering of lanthanum chromites involves high temperatures and low oxygen partial pressures (above 1700 degrees C and an oxygen activity below 10-9. The authors recent results on LaCrO3-LaMnO3 have shown that the significant improvement on sinterability was achieved with at least 50% Mn substitution for Cr. However, that much Nm on the Cr site has shown to negative effects;electrical conductivity of such compounds decreased. Stability under reducing conditions was diminished. This paper describes the sintering of LaCrO3 in air at temperatures below 1400 degrees C with varying the composition without the deterioration of either the electrical conductivity or stability under reducing conditions