Thermodynamic remodeling of the Co–Ga system

The thermodynamic properties and phase relations of the Co–Ga binary system are remodeled based on the CALPHAD approach. In this work, CoGa(ββ) is considered to be non-stoichiometric and CoGa3 to be stoichiometric. The ββ phase is thermodynamically described by a two-sublattice model (Co,Ga)0.5 (Co,V a)0.5. The stability of the ββ phase is restricted in the low-temperature regions by giving necessary driving force constraints. The lattice parameters and enthalpy of formation of the ββ and CoGa3 phases have been compared with first-principles calculations based on density functional theory. The calculated Co–Ga phase diagram is compared to previously calculated ones.