Relationship of formation of Cu-Sn-Ag alloyed layer at the interface of Pb base solder and copper and joint properties in press soldering.

In order to increase the strengths of soldered joints, a new press-soldering method was investigated. In this method, materials of low melting points and low strengths (mainly Pb) were discharged from the joint interface and an alloyed layer of high strength was left.The lap joint which was press-soldered at 550°C with 3 kgf/mm2 pressure using Pb-1.5%Ag-1%Sn solder fractured at the Cu base plate.An alloyed layer which contained mainly Cu, Sn and Ag was formed at the joint interface and Pb was not detected.