The durability of metallic zinc coatings for protecting steel from corrosion has been tested and proven for 100 years to be dependent on the mass or thickness of the coating. Metallic zinc coatings applied to steel by different methods have, for all practical purposes, similar corrosion resistance per unit mass. It is important to choose a zinc coating with the appropriate thickness for the desired service life in a given exposure environment. Metallic zinc coatings provide atmospheric corrosion protection for steel first as a barrier coating, and secondly as a sacrificial anode. The ability to form an insoluble zinc patina on the surface of the zinc coating allows for slow, uniform corrosion of the coating. Due to the uniform linear rate of corrosion, long term performance of zinc coatings can be predicted.
