Prediction of phase equilibria and thermal analysis in the Bi–Cu–Pb ternary system

The knowledge about phase diagram of the Bi–Cu–Pb ternary system is of importance in development of copper–lead based bearing materials, soldering and in refining of copper and lead. In this work, the phase diagram of the Bi–Cu–Pb ternary system was calculated by the CALPHAD method using binary thermodynamic parameters included in the COST 531 database. The results include liquidus projection, invariant equilibria and three vertical sections with molar ratio Cu:Pb = 1, Cu:Pb = 1:3 and Bi:Cu = 1. Alloys, with compositions along three predicted vertical sections, were measured using differential scanning calorimetry (DSC). The experimentally determined phase transition temperatures were compared with calculated results and good mutual agreement was noticed.