The microstructure of Cu joint soldered with a new Cu coated Ni foam reinforced Sn composite solder

It is imperative to develop a high-performance Sn-based lead-free solder to obtain high strength, high temperature resistance and high precision Cu connections. In this study, Cu joints were soldered with a new Cu coated Ni foam reinforced Sn composite solder, and the effects of metal foam composition and soldering time on the microstructure and mechanical properties of joints were revealed. The molten Sn matrix was consumed in under 60 min, as a result of the rapid metallurgical reaction with both the high surface area of the Cu coated Ni foam skeletons and also with the Cu substrates. This is accompanied by the formation of the high melting point (Cu,Ni)(6)Sn-5 and Cu3Sn phases. The results show that Cu coated Ni foam reinforced Sn composite solder can improve the shear strength of Cu joints that have potential to serve at high temperature.