Thermodynamic assessment of the Au–Ga system

The Au–Ga system was critically assessed by means of CALPHAD technique. Based on the experimental data in the literature, the excess Gibbs energies of the solution phases (liquid, fcc, orthorhombic) were modeled with the Redlich–Kister equation. The intermetallic compounds αAu7Ga, βAu7Ga2, β′Au7Ga2, γAu7Ga3 and γ′Au7Ga3, which have homogeneity ranges, were treated as the formula Au7(Au,Ga), (Au,Ga)7Ga2, (Au,Ga)7(Au,Ga)2, (Au,Ga)7(Au,Ga)3 and (Au,Ga)7(Au,Ga)3, respectively, using a two-sublattice model with Au and Ga or Au on the first sublattice, Au and Ga or Ga on the second one. The two compounds AuGa and AuGa2 were treated as stochiometric compounds. A set of self-consistent thermodynamic parameters of the Au–Ga system was obtained.

Research highlights▶ The Au–Ga system was critically assessed by means of CALPHAD technique, in which the solution phases were modeled with the Redlich–Kister equation, the intermetallic compounds αAu7Ga, βAu7Ga2, β′Au7Ga2, γAu7Ga3 and γ′Au7Ga3 were treated as the formula Au7(Au,Ga), (Au,Ga)7Ga2, (Au,Ga)7(Au,Ga)2, (Au,Ga)7(Au,Ga)3 and (Au,Ga)7(Au,Ga)3, respectively, and two compounds AuGa and AuGa2 were treated as stochiometric compounds. ▶ A set of self-consistent thermodynamic parameters of the Au–Ga system was obtained.