The aim of this work was theoretical and experimental study of phase equilibria and thermodynamic properties of Sn-Zn-X (X = Bi, In, Pd) ternary systems and relevant subsystems.
The theoretical modelling is based on a new thermodynamic database, using the latest SGTE unary data, which was compiled by authors in the scope of the COST531 project. The CALPHAD approach was used for the modelling in this work. The experimental verification of some discrepancies between the calculated and expected experimental phase diagrams was carried out.
Several binary and ternary alloys were prepared, e.g. Bi-Zn (200°C and 240°C), Pd-Zn (300-400°C), Bi-Sn-Zn (100°C, 200°C), In-Sn-Zn, which were annealed for a long time (up to one month) at the temperatures below melting point. The alloys were analysed by SEM (EDX, WDX) and the phase data was used for the verification of the theoretical predictions. The DTA analysis was also employed to measure important phase transformation temperatures.
The thermodynamic database with tested and verified data for the mentioned systems was created as a part of a broader thermodynamic database oriented towards lead-free solders. This project now continues with the study of the Bi-Sn-Zn-X (X = Pd, In, Ag, Cu, Sb) quaternary systems.
This work is supported by the COST projects Nos. OC 531.001 and OC 531.002 of Ministry of Education of the Czech Republic.