Galvanic corrosion analysis of a Bi–Zn solder alloy coupled to Ni and Cu substrates

Abstract

Corrosion has become a frequent and significant issue in the electronics industry. For this reason, galvanic corrosion of soldered joints, i.e. when solder alloys are in contact with a metallic substrate, is so important. The present study aims to investigate the corrosion behaviour of the Bi-2.7wt-%Zn solder alloy when in contact with Cu and Ni substrates in a 0.06M NaCl solution. Polarisation curves show that Ni and Cu have nobler behaviour than the Bi-Zn alloy. However, although the Bi-Zn alloy exhibits active corrosion behaviour, the open circuit potential tends to shift toward more positive potentials over time. The galvanic current densities (i galv ) of both Bi-Zn alloy/Ni and Cu couples are initially similar and three times higher than the corrosion current density of the Bi-Zn alloy. However, the couples show a decrease in i galv. , with time and the couple formed with Ni has produced the lowest galvanic current density.