Preparation of La1 − x − y Ca x Sr y CrO3 with High-Density Structural Phase Transition and Electrical Conduction Properties

Combining simultaneous substitution of Ca and Sr for the La site in LaCrO 3 and pulverization of calcined particles with planet-type yttria-stabilized ZrO 2 ball mill La 0.70 Ca 0.30-x Sr x CrO 3 , ceramics with sintering density of more than 93% were successfully prepared. Not only sintering properties but also structural phase transition behavior, such as temperature, variation of enthalpy, and entropy, of La 1-x-y Ca x Sr y CrO 3 could be controlled by alkaline earth composition. The variation of the transition behavior on Sr content could be fairly explained with the model, assuming that the phase with high crystal symmetry has high thermodynamic stability, i.e., low standard Gibbs energy of formation. Because La 0.70 Ca 0.05 Sr 0.25 CrO 3 not only has high sintering properties but also no structural phase transition between room temperature to solid oxide fuel cell (SOFC) operation and equal electrical conductivity to that of La 0.70 Ca 0.35 CrO 3 , which was reported to be a promising material for SOFC interconnectors, it can be expected that La 0.70 Ca 0.05 Sr 0.25 CrO 3 is a superior candidate to La 0.70 Ca 0.35 CrO 3 as interconnector material for SOFCs.