REACTION OF CERIUM OXIDE WITH ZIRCONIUM AND YTTRIUM OXIDES AT 1250°C

Phase relationships in the ternary system ZrO₂― Y₂O₃― CeO₂were investigated by x-ray diffraction analysis and electron microscopy for the first time, and phase relationships in the binary systems ZrO₂― CeO₂and CeO₂― Y₂O₃defined more accurately at 1250°C over the entire range of concentrations. The 1250°C isothermal section of the phase diagram for ternary system was constructed. Specimens were prepared from nitrate solutions by evaporation, drying, grinding, and subsequent annealing at 1250°C. The systems were characterized by the formation of broad solid solution ranges based on C -Y₂O₃,F-CeO₂,F-ZrO₂,and narrow based on T-ZrO₂and δ-phase. No new phases were found in the systems. The path of isoparametric lines in the F-ZrO₂solid solution field suggests that yttrium and cerium ions can substitute for each other without appreciable substitution of zirconium ions.