Thermodynamic Stability of LaCrO3 and CaZrO3 Using a Solid-state Galvanic Cell Method

Thermodynamic stability of CaZrO3 with respect to LaCrO3 was investigated. The possible products of the reaction are La2Zr2O7 and CaCr2O4. The standard Gibbs free energy change for this reaction at T = 1273 K was calculated. To this purpose the standard Gibbs free energy of formation (from oxides) of LaCrO3, CaZrO3, La2Zr2O7 and CaCr2O4were obtained from the measurements of electromotive force (EMF) of respective solid-state galvanic cells. LaCrO3 was confirmed to be able to react with CaZrO3 spontaneously. However, the solid solutions based on LaCrO3, in which the activity of LaCrO3 at T = 1273 K reached the values below 0.168, are thermodynamically stable with respect to CaZrO3.