Thermodynamic assessment on the Pb–Ca–Sn ternary system

Abstract

Thermodynamic modelling of the Pb–Ca–Sn ternary system was carried out with the help of the CALculation of PHase Diagrams (CALPHAD) method.The binary borders related to the ternary system were investigated. The lead–tin system is already calculated, the calcium–tin and calcium–lead systems can be described with the association model in binary liquid. The establishment of the modelling of the Pb–Ca–Sn phase diagram was done after collecting own experimental information. The introduction of new interaction parameters related to the ternary liquid, leads to an accurate restoration of the experimental data.Calculated isothermal, isoplethal sections and liquidus surfaces are presented. They confirm that the calcium solubility in lead matrix drastically decreases with the introduction of tin as well as with the decreasing of temperature. The industrial process applied to the lead–calcium–tin alloys finds some justifications in the calculated phase diagram.