Effect of rare-element (Ga) addition on the microstructure and mechanical properties of Sn-0.7Cu and Sn-0.7Cu-0.05Ni lead-free solder alloys

Abstract

The effects of rare element Ga on wettability, microstructure, and mechanical properties of Sn-0.7Cu (SC) and Sn-0.7Cu-0.05Ni (SCN) lead-free solder alloys were investigated. The experimental results show that Ga plays a positive role in improving the wettability and the microstructure of the solder. When the content of Ga is at 0.05 wt%, the grain size of the solder is smaller and the hardness is enhanced greatly. It is also found that the thickness of the IMCs at the solder/Cu interface is reduced with proper addition of Ga. The increase of mechanical properties may be related to the refining of IMCs of the solder due to Ga addition.