Zinc is one of the metals most widely used as a protective coating for iron and steel. Aside from economic advantages there are two factors which account for the widespread use of zinc coatings for corrosion resistance; first, the natural corrosion resistance of zinc; and second, the electrochemical protection afforded to the steel base at bared areas. When contacting zinc and steel are exposed to an electrolyte, a galvanic cell is formed in which the steel usually is cathodic and is protected by the galvanic current from the anodic zinc. Because of this protection, certain zinc coated steel products have come to be known as “galvanized steels.”
One of the large outlets for galvanized steel is the handling of hot and cold domestic water supplies. By and large this has been a very successful application. However, in recent years there have been several reports of unsatisfactory performance of galvanized steel...
