2020 Volume 69 Issue 1 Pages 17-25
In the present study, possible effect of deposits on the corrosion of copper pipes in concentrated cooling water has been examined. It was considered that during the localized corrosion of copper pipes, the cathodic process took place on the intact sites of carbonaceous films, whereas the anodic process occurred on their defective sites. The deposits covering the defects of carbonaceous films significantly affected the corrosion of copper pipes. In particular, the presence of iron rust strongly enhanced the anodic reaction, resulting in severe corrosion. The enhanced anodic reaction was attributed to the suppressed formation of a protective oxide film most likely due to the lower pH of the areas located beneath the iron rust. It was suggested that the pretreatment to form a protective copper oxide film onto the copper pipe surface inhibited the corrosion process beneath the iron rust deposit.