Contribution of the associated complex in a binary liquid to model the Ca–Pb–Sn ternary system

Abstract

Thermodynamic modeling of the Ca–Pb, Ca–Sn and Ca–Pb–Sn systems was carried out with the help of the CALculation PHase Diagram (CALPHAD) method. The thermodynamic parameters related to these systems were determined from experimental phase diagram and thermodynamic information available in the literature and by our own ternary experimental investigations (X-ray diffraction, metallographic and thermal analyses). The calcium–tin and calcium–lead systems can be described with the association model for the binary liquid with ‘Ca2Sn’ and ‘Ca2Pb’ as the associated species composition. The introduction of new interaction parameters related to the binary and ternary liquids, leads to an accurate restoration of the most important experimental data. Thus, industrial process applied on the lead calcium tin alloys used as electrode materials in lead acid batteries find some justifications.