Thermodynamic evaluation of the BaO-CaO-YO1.5 system

A series of experiments were performed to study the solid solubility of CaO in BaY2O4, and the observed results were then adopted to the present thermodynamic evaluation to derive a set of thermodynamic database for the BaO-CaO-YO1.5 system. The database was constructed by the CALPHAD method where the binary parameters from the BaO-CaO and CaO-YO1.5 systems were presently optimized, those from the BaO-YO1.5 system were simulated by our previous assessments, and only limited amount of ternary parameters were introduced. All the model parameters were emanated from the Bragg-Williams approximation where the liquid and terminal solid-solution phases were treated by the one-sublattice model, and two ternary intermediate phases, named BCY (BaCa2Y6O12) and BaY2O4, were described by the three-sublattice and two-sublattice models, respectively. Good agreement between the experimental data and the calculated results demonstrates that the present thermodynamic database is self-consistent and credible and able to be used to design novel refractory.