Thermodynamic modeling of the YO_1.5-ZrO₂ system

The YO_1.5-ZrO₂ system consists of five solid solutions, one liquid solution, and one intermediate compound. A thermodynamic description of this system is developed, which allows calculation of the phase diagram and thermodynamic properties. Two different solution models are used - a neutral species model with YO_1.5 and ZrO₂ as the components and a charged species model with Y³⁺, Zr⁴⁺, O^2-, and vacancies as components. For each model, regular and subregular solution parameters are derived from selected phase equilibrium and thermodynamic data. The neutral species and charged species modeling results are compared.