Thermodynamic modeling of the ZrO2–YO1.5 system

In the present work, an optimized set of Gibbs energy functions is proposed for the Y–Zr–O ternary system. We focus on the ZrO2–YO1.5 quasi-binary system, but reoptimizations of the Zr–O and Y–O binary systems are included as well. The parameters for the Y–Zr binary system were taken from a previous assessment. O2–YO1.5 system was treated as a quasi-binary section of the Y–Zr–O ternary system. The existing experimental data on the ZrO2–YO1.5 system were carefully reviewed. The related parameters were optimized using both thermodynamic data and phase diagram data. A calculated phase diagram of the ZrO2–YO1.5 system is presented. Our optimization agrees well with most experimental data. Two calculated isothermal sections of the Y–Zr–O system at 1500 and 2000 K are also included.