Modelling of Thermodynamic, Thermophysical and Physical Properties of Lead-Free Solder Alloys

The demand for new and improved lead-free solder (LFS) alloys grows steadily as the need for reliable lead-free electronic products increases. Thermodynamic calculations have proved to be an important tool in providing information for the design and understanding of new LFS systems. However, such tools often fall short from directly providing the information that is actually required by the end users, such as physical and thermophysical properties. In the present work, models have been created such that a full set of such properties can be calculated for solder alloys for the multi-component system Sn-Ag-Al-Au-Bi-Cu-In-Ni-Pb-Sb-Zn. The properties, given for both the overall alloy or for each phase if required, include coefficient of thermal expansion, densities, various modulii, thermal conductivity, liquid surface tension and viscosity, all as a function of composition and temperature (extending into the liquid state)