Thermodynamic modeling of the In-Pt-Sb system

The In-Pt-Sb system is modeled using the CALPHAD technique. The solution phases (liquid, fcc(Pt), rhom(Sb) and tetra(In)) are described as substitutional solution. The enthalpies of formation of the intermetallic compounds, Pt ₇Sb, Pt₃Sb, Pt₃Sb₃, PtSb, PtSb ₂ are calculated using firstprinciples calculations. In the In-Pt-Sb system, the compounds In₃Pt₂, In₂Pt, In ₇Pt₃ in the In-Pt binary system and the compounds PtSb₂ and PtSb in the Pt-Sb binary system are treated as line compounds (In,Sb)mPtn according to experimental solid solubility of the third component. The compound In₅Pt₆ is treated as (In,Pt,Sb)₅ (In,Pt)₆ based on its thermodynamic model in the In-Pt system and experimental solid solubility of Sb in the In-Pt-Sb system. The thermodynamic model of compound InPt3 keeps the order- disorder transition model with fcc(Pt) solid solution which was used in the In-Pt binary system, and is treated as (In,Pt,Sb)_0.25 (In,Pt,Sb)_0.75 Other compounds InPt, In₉Pt₁₃, aIn₂Pt₃, bIn₂Pt₃, InPt₂ and InSb in the In-Pt-Sb system keepthe same thermodynamic models as those in binary systems. Based on the published experimental isothermal sections, vertical sections and the liquidus surface projection, the In-Pt-Sb system is modeled, and a set of self-consistent thermodynamic parameters is obtained.