The thermodynamic properties of LaCrO3 and related compounds have been estimated and utilized to correlate sinterability with phase relations in the La-M-Cr-O (M = Mg,Ca,Sr) systems. Chemical equilibria calculations reveal that calculated vapor pressures of gaseous chromium oxides (especially Cr03) can be well correlated with our previous experimental results on sinterability. The poor sinterability can be ascribed to the formation of a thin layer of Cr2O3(s) which is formed from incongruently vaporized Cr03(g) at the interparticle neck during the initial stage of sintering in air. Improvement of sinterability of Cr203-based oxides can be achieved by removing this Cr203 layer or by decreasing Cr03(g) vapor pressure to prevent the formation of Cr203 layer. These suggest that (LaI- xCax)Cr03perovskites are the most suitable materials for high sinterability, since these materials have the low Cr03 vapor pressure without precipitation of La203.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry