Phase diagram of the ZrO2–Gd2O3–Al2O3 system

Isothermal sections of the phase diagram for the ZrO2–GdO3/2–AlO3/2 system have been constructed based on experimental phase equilibrium data at 1250 and 1650 °C. They are in a good agreement with calculations which have also been performed in the present study. The liquidus and solidus surfaces have been experimentally determined. The temperature of the eutectic reaction liquid = Al2O3 + fluorite + GdAlO3 was measured using differential thermal analysis (DTA) to be 1662 °C. The liquidus surface calculated in this work using a non-zero ternary interaction parameter in the liquid phase agrees with the experimental data. A thermodynamic description of the ZrO2–GdO3/2–AlO3/2 system based on an ionic sublattice model for the solid and liquid phases consistent with the experimental data has been derived.