The influence of microstructure on surface phenomena: Rolled zinc

A series of rolled zinc (Zn) alloys, all with purity exceeding 99.7%, have been shown to have material losses due to corrosion spanning an order of magnitude during field exposure trials. In order to explain these large variations in corrosion performance, the influence of alloying additions and microstructure has been investigated. Corrosion rates were found to increase with increasing alloying additions of copper (Cu) and, depending upon its distribution, titanium (Ti). The influence of grain size was investigated using a series of heat-treated rolled zinc specimens. Binary Zn–Ti and Zn–Cu alloys were used to study the independent influences of Ti and Cu on zinc corrosion. An increased understanding of the influence of Cu:Ti ratios has been developed and an approach to optimise the corrosion resistance of rolled zinc materials has been proposed.