The influence of microstructure on the corrosion of rolled zinc

Abstract

Rolled zinc (Zn) samples have long been used as a standard reference to estimate the corrosivity of atmospheric environments. Previous work has shown that a series of rolled zinc alloys, all with purity exceeding 99.7%, had corrosion rates 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 grain size, alloying additions of copper (Cu) and, depending upon its distribution, titanium (Ti). This work reports upon the influence of grain size on corrosion rates, which was investigated using heat-treatment of the rolled zinc and their subsequent analysis using both laboratory and eight-year field exposures. A model for correlating the corrosion rate of rolled zinc alloys with variable grain size, Cu and Ti additions is proposed. Show more