Experimental investigation and thermodynamic calculation of the Cu–In–Sb phase diagram

The phase diagram of the Cu–In–Sb ternary system is of importance in predicting the interface reaction between In-based solder materials and the Cu substrate. The liquidus surface, invariant equilibria and four vertical sections of the Cu–In–Sb ternary system were calculated by the CALPHAD method using binary thermodynamic parameters included in the COST531 database. Alloys, representing two isopleths from indium corner with molar ratio of copper and antimony equal to 1/3 and 1/1 and two isopleths from antimony corner with molar ratio of indium and copper equal to 3/1 and 1/1 were measured with the DTA (Differential Thermal Analysis) and DSC (Differential Scanning Calorimetry). The experimentally determined phase transition temperatures were compared with calculation results and good mutual agreement was noticed.