Selection of Coatings over Galvanizing
by Kevin Irving, Marketing Manager of Northern Operations, AZZ Galvanizing
Hot-dip galvanizing consists of a layer of zinc applied over a steel substrate to provide corrosion protection to the underlying steel and offers effective long-term corrosion protection for steel in chemically neutral atmospheric service. However, in service environments where rapid depletion of the zinc (galvanized) layer can occur, protective coatings are frequently applied over the galvanized surface to provide a more effective corrosion protection system. Protective coatings are also used to overcoat aging and deteriorating galvanizing to restore corrosion protection to steel no longer fully protected by the sacrificial zinc (galvanized) layer. Overcoating allows a variety of finish colors to be applied to galvanized surfaces for safety, identification and aesthetic purposes.