Abstract
A procedure for corrosion protection of galvanized steel in slightly acidic media has been proposed, based on surface amalgamation by contact with Hg2+ solutions. The treatment procedure and the changes it effects in the morphology of the Fe–Zn alloyed layers of galvanized coatings are described. The amalgamated layer reaches a thickness of 75 μm and includes the η and ζ layers, penetration into the ζ layer being by grain boundary diffusion. A reduction in the corrosion rate of surface amalgamated galvanized pipe in contact with slightly acidic media, ranging from ten fold at pH 4–6 to one hundred fold at pH <4, is due to cathodic control resulting from the high overvoltage for hydrogen discharge on Zn–Hg alloys.
Get full access to this article
View all access options for this article.