CHEMICAL COMPATIBILITY BETWEEN STRONTIUM-DOPED LANTHANUM MANGANITE AND YTTRIA-STABILIZED ZIRCONIA

Equimolar powder mixtures and multilayer pellets of single-phase Sr-doped lanthanum manganite perovskite materials Lay-xSrxMnO3 with La content y = 1 and 0.95 and Sr content 0 less than or equal to x less than or equal to 0.5 were annealed in air with 8 mol% Y2O3-ZrO2 at 1470 K up to 400 h and at 1670 K up to 200 h. X-ray diffraction and electron probe microanalysis confirmed the formation of La2Zr2O7 or SrZrO3 depending on the composition of the perovskites. No reaction products could be detected for La0.95-xSrxMnO3 with 0.2 less than or equal to x less than or equal to 0.4 after annealing for 400 h at 1470 K, and for the perovskite La0.65Sr0.3MnO3 even after annealing for 200 h at 1670 K. The results demonstrate the improved chemical compatibility of La-deficient perovskites against reaction with zirconia and can provide a basis for the selection of a sufficiently chemically stable material for the air electrode of solid oxide fuel cells.