Thermodynamic assessment of B2O3-MgO binary system

The B2O3-MgO system has been thermodynamically assessed by CALculation of PHAse Diagram (CALPHAD) technique using Thermo-Calc software. An ionic two-sublattice (I2SL) model, (Mg2+)p(O2−, BO33-, B4O72-, B3O4.5)Q, is proposed to describe the liquid phase in the system, whereas the Redlich-Kister expression is used to formulate its excess Gibbs energy. All the solid intermediate compounds have been treated as stoichiometric compounds and their Gibbs energy is modeled following Neumann-Kopp's rule. A set of self-consistent thermodynamic parameters for the B2O3-MgO system are then obtained and the calculated phase diagram and thermodynamic properties of the B2O3-MgO system agree well with the available phase diagram and experimental data in the literature.