Atomizing effect on Sn-Zn based solder alloy

Sn-Zn based solder alloys are expected to be a potential candidate as a lead-free low temperature solder because of its melting point close to that of Sn-Pb. There are, however, several problems in practical application. Cu-Zn intermetallic compound (IMC) layer formed at the solder and Cu substrate interface leads to degradation of adhesion strength. In order to prevent the formation of Cu-Zn IMC, we have added some additives (Ni and Cu) to the Sn-Zn solders. We have also investigated the quenching effect by the atomization process in these Sn-Zn-(Ni and Cu) solders. For the pre-atomized solders, Cu-Zn IMC layer is formed at the interface. On the other hand, for the atomized solders, Cu-Sn IMC layer which is usually seen in Sn-Pb solder is observed instead.