ANALYSIS OF CHEMICAL INTERACTIONS BETWEEN STABILIZED ZIRCONIA AND PEROVSKITES

LaMnO3-based perovskites are used as cathode materials in solid oxide fuel cells (SOFC). A major aspect for their applicability is their che mical inertness in connection with the electrolyte material YSZ (Zr0.8 5Y0.15O1.93) against zirconate formations. Perovskites with the compos ition La-y-x(Sr, Ca)(x)Mn1-uCouO3 (y = 1.0 and 0.95; x = 0-0.2 and 1; u = 0 and 0.2) were investigated with regard to their reactivity with YSZ at different reaction times and temperatures. Powder mixtures and double-layer reaction couples were used for the investigations. XRD ph ase analyses, SEM/EDX and EPMA were applied for the characterization o f the annealed samples. La-deficient perovskites (y = 0.95) partially substituted by Sr and Ca improve the chemical compatibility of perovsk ite compositions towards YSZ. Sr-containing perovskites were found to have a higher reactivity than Ca perovskites for La2Zr2O7 formation. O n the other hand enhanced Ca diffusion into YSZ was observed. Co subst itution on Mn lattice sites decreased the chemical compatibility, espe cially for Sr containing perovskites.