Thermodynamic Analysis of Reaction Profiles Between LaMO3    (  M  = Ni , Co , Mn )  and ZrO2

Chemical reactions of and have been analyzed using chemical potential diagrams for the La‐Zr‐M‐O systems under a condition of . A vs. plot is appropriate for representing diffusion paths, because the layered arrangement of the reaction zone corresponds well to the geometrical configuration of stability polygons of reactants ( and ) and products (, MO, , etc.). A complicated arrangement including a ternary perovskite phase, , observed in the couple can be represented by a simple diffusion path having the same slope in the chemcial potential diagram as in the couple. The effect of lanthanum nonstoichiometry for has been discussed in relation to formation and manganese dissolution into YSZ cubic phases.