Suppression of interfacial intermetallic compounds between Sn–9Zn solder and Cu-substrate by adding Cu-particles in the solder

Abstract

The effects of adding Cu-particles into Sn–9Zn solder on the growth behaviors of the interfacial intermetallic compounds (mainly γ-Cu5Zn8) between the solder and Cu-substrate were investigated in soldering and aging duration. It is approved that the Cu-particles dispersion in the solder can effectively suppress the growth rate of the intermetallic compounds at the solder/Cu-substrate interface compared with that without adding Cu-particles. The results also reveal that the Cu-particles in the solder are in situ transformed into the intermetallic compounds due to its reaction with single Zn. It is very interesting that the growth rate of the intermetallic compounds at solder/Cu-particles interface is larger than that at solder/Cu-substrate interface. With increasing the amount of Cu-particles the thickness of the intermetallic compounds at solder/Cu-substrate decreases continuously. The intermetallic compounds growth in aging obeys the parabolic rule whether adding Cu-particles or not.