Dense sintered conditions and sintering mechanisms for alkaline earth metal (Mg, Ca and Sr)-doped LaCrO3 perovskites under reducing atmosphere

Dense sintered conditions and sintering mechanisms of alkaline earth metal (AE=Mg, Ca and Sr)-doped LaCrO3 perovskites with stoichiometric compositions under a reducing atmosphere have been investigated. Relative densities ≧94% were obtained after firing at 1800 °C for the LaCr0.9Mg0.1O3 and at 1900 °C for the La0.9Ca0.1CrO3 and the La0.9Sr0.1CrO3 in an Ar–CO atmosphere. It was found that during the sintering process, MgO was deposited into the grain-boundary from the perovskite particles for the Mg-doped sample, and the AE-rich phase percolated from the perovskite particles into the grain-boundaries for the Ca- or Sr-doped sample. The deposition and percolation contribute to enhance the densification of the AE-doped lanthanum chromites.