A critical review on performance, microstructure and corrosion resistance of Pb-free solders

In the quest for viable alternatives to lead-based solders, electronic industries have started to focus on several potential lead-free solder alloys. After reviewing more than 100 recent studies, the present paper attempts to report the feasibility of various lead-free solder alloys in terms of performance, microstructure, corrosion resistance, and cost analysis. It reveals that there is a lack of scientific data based on which solid decisions on reliable lead-free solders, particularly their composition, can be made. Laboratory tests and data from actual services suggest that Sn-Ag-Cu solder alloys are perhaps the best choices for electronic industries. However, some problems in their practical usage must be addressed. This comprehensive review presents the major shortcomings of lead-free solders and possible solutions. Finally, a number of issues have been reported, which need to be confirmed in further studies.