Maximum Fluidity Length of Commercial Solder Alloys and the Effects of Ni and Co in Sn-0.7wt%Cu Solder Alloys

To make electronic packaging with minimal defects, during the wave soldering process, the fluidity of the solder alloy is an important parameter. In this research we measured the maximum fluidity length of 16 commercially available solders. We found alloy compositions including Ni have higher fluidity lengths (similar to eutectic Sn-37Pb solders) when compared to other Pb-free solder alloys. The effects of Ni and Co on the maximum fluidity length in Sn-0.7Cu alloys is discussed with respect to the solidification process and microstructures. The optimum concentrations of Ni and Co in Sn-0.7Cu alloys to achieve highest maximum fluidity length was investigated.