The corrosion performance of a galvanized coating is classified according to the environmental conditions in which the coated material will be used. Factors such as moisture level, environmental conditions, the pH value affecting the surface, the chloride level in the atmosphere, contact with other chemicals (acids and alkalis react very quickly with zinc), and ventilation conditions affect the performance of the galvanizing.
Sulfur dioxide in particular has a major effect on the atmospheric corrosion of zinc. Other effects include moisture, salt, and nitrogen. The graphs below detail the corrosion performance of zinc.
