Microstructural modifications and properties of low-Ag-content Sn-Ag-Cu solder joints induced by Zn alloying

The addition of small amounts of Zn into Sn-2.0Ag-0.7Cu solder leads to formation of new types of flower-like or coarse dendrite γ-(Cu, Ag)5Zn8 intermetallic compounds, which controls the overall properties. The optimum percentage of Zn to enhance the inclusive properties was 1.5% Zn.289