Thermodynamic modeling of the Ga–Pt–Sb system

Abstract

The Ga–Pt–Sb system was modeled using the CALPHAD (CALculation of PHAse Diagram) technique. Solution phases, liquid, fcc(Pt) and rhom(Sb), of the Ga–Pt–Sb ternary system were modeled with the substitutional solution model. The compounds, Ga6Pt, Ga7Pt3, Ga2Pt, Ga3Pt2, GaPt, Ga3Pt5, and GaPt2 of the Ga–Pt system, and PtSb2, PtSb, Pt3Prod. Type: FTPSb2, and Pt7Sb of the Pt–Sb system, were treated as line compounds Ptm(Ga,Sb)n in the Ga–Pt–Sb system. The compounds Ga3Pt and Pt5Sb were treated as (Ga%,Pt,Sb)3(Ga,Pt%) and (Pt%,Sb)5(Ga,Pt,Sb%) in the Ga–Pt–Sb system on the basis of thermodynamic models of the respective binary system. A set of self-consistent thermodynamic parameters was obtained. Using these thermodynamic parameters, the experimental isothermal section phase relation at 773K, the vertical sections at 25at% Pt, the GaPt–GaSb, Ga2Pt–GaSb, Ga7Pt3–GaSb, and GaPt–PtSb2 sections and the partial invariant reactions in the Ga–Pt–Sb system were well reproduced.