Thermodynamic Reassessment of BaO-YO 1.5 System

Based on the available experimental information, the thermodynamic reassessment of BaO-YO1.5 system was carried out. The liquid phases were modeled with substitutional solid solution model, the compounds BaYO2O4 and Ba3Y4O9 were treated as stoichiometric phases, the BaOss (halite BaO solid solution), (α-Y2O3 and β-Y2O3 were treated as pure compounds. The existing discrepancies were summarized, and a new assessment was carried out based on the formation enthalpy of two compounds (BaY2O4 and Ba3Y4O9). The thermodynamic parameters of all phases were optimized by Calphad method, a self consistent set of the optimized Gibbs energy parameters was derived, which can be safely used to extrapolate into the multicomponent system. Compared with the experimental data and the results in this work as well as the results reported previously, it is demonstrated that the present thermodynamic assessment is consistent with the most of experimental data.