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.