SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF A NEW SYSTEM - ZRO2-Y2O3-RUO2

New compounds belonging to the pseudo-ternary system ZrO2-Y2O3-RuO2 ha ve been synthesized from nitrates as precursors. The general formula w as [(ZrO2)(0.91)(Y2O3)(0.09)](1-x) (RuO2)(x) with 0 less than or equal to x less than or equal to 20 mol% RuO2. In order to avoid thermal de composition and to obtain the beat sample crystallinity, the last firi ng was performed at 900 degrees C. X-ray diffraction measurements prov ide evidence of a solid solution limit at 10 less than or equal to x < 12.5 mol% RuO2 with the cubic fluorite-type structure. Microstructura l analyses show samples with high porosity and heterogeneity in grain size and ruthenium composition.