Abstract
A thermodynamic assessment was conducted using experimental data on the phase boundaries of the Co–Ga system and other related thermochemical properties. In addition, the experimental data for vacancy concentration of the β-phase were incorporated. In this analysis, the intermetallic β phase was described using the sublattice model (Co,Ga)0.5(Co,Va)0.5. The CoGa3 phase is a stoichiometric compound. There is a good agreement between the calculated and the experimental phase boundaries, and the thermodynamic properties and vacancy concentrations of the β phase were reproduced satisfactorily.