Development of high strength Sn–Cu solder using copper particles at nanolength scale

In this study, varying amounts of nanolength scale copper particles were incorporated into tin by microwave sintering assisted powder metallurgy route. Near dense materials exhibiting near equiaxed grains were obtained. Coefficient of thermal expansion reduced marginally due to the presence of Cu particles. Results of tensile testing revealed that with the addition of 0.35 vol.% (∼0.43 wt.%) of Cu in pure Sn, a significant improvement in yield strength (∼233%) and ultimate tensile strength (∼159%) is realized, when compared with that of commercially available Sn–0.7 wt.% Cu solder. Furthermore, Sn–Cu solder materials developed here also exhibited comparable resistivity with that of eutectic Sn–0.7 wt.% Cu commercial solder. The morphology of pores and intermetallic compounds were found to be the dominating factors affecting the strength of the materials synthesized in this study.