Preliminary Study on The Effect of Zn Additions on Sn-0.7Cu Lead-Free Solder

Sn-0.7 Cu lead-free solder is an alternative solder materials that suitable to replace Sn-Pb solder in electronic manufacturing. However, it has weakness of high melting temperature and lower mechanical strength. In this study, the change in microstructure, elements, structural and melting point of Sn-0.7Cu after addition of different composition of Zn element was discussed. The result shows after addition small amount of Zn, a refinement microstructure of Sn-0.7Cu-xZn solder alloy has been obtained and the melting point of the solder was decreases from 227.7 °C to 225.7 °C. Besides, the formation new phase of Cu5Zn8 was investigated by scanning electron microscope (SEM) followed by energy-dispersive x-ray spectroscopy (EDX) and x-ray diffraction (XRD). In addition, the behaviour of Sn-0.7Cu-xZn solder alloy can be further studied via open circuit potential (OCP) in order to determine the corrosion potential.