The confirmation of phase equilibria in the system ZrOCeO2 below 1400°C
Critical review of the phase diagrams proposed previously suggested incomplete establishment of the phase equilibria in the system ZrO2-CeO2 below 1400°C. Application of hydrothermal techniques enabled us to attain the equilibria in this system. The tetragonal SS (solid solution) was no longer stable below 1000°C, where it decomposed into the stable monoclinic SS and cubic SS. The solubility limit of the tetragonal or cubic SS was 23 wt%(18 mol%) CeO2 or 79 wt%(73mol%) CeO2, respectively at 1400°C. That of the monoclinic or cubic SS was 5 wt%(3.5 moI%) CeO2 or 96 wt%(95mol%) CeO2, respectively at 800°C. Thermochemical calculation appears to make it possible to predict true equilibria in this system.