Reaction of Cerium Oxide with Zirconium and Yttrium Oxides at 1250°C

Abstract

Phase relationships in the ternary system ZrO2 ― Y2O3 ― CeO2 were investigated by x-ray diffraction analysis and electron microscopy for the first time, and phase relationships in the binary systems ZrO2 ― CeO2 and CeO2 ― Y2O3 defined 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-ZrO2 and δ-phase. No new phases were found in the systems. The path of isoparametric lines in the F-ZrO2 solid solution field suggests that yttrium and cerium ions can substitute for each other without appreciable substitution of zirconium ions.