Hot dip galvanizing provides steel or iron with a robust defense against corrosion through two primary mechanisms:
Barrier Protection: The process creates a metallurgical bond between the steel/iron surface and molten zinc, resulting in a multi-layered coating of zinc and zinc-iron alloy. This zinc coating reacts with moisture in the atmosphere, forming zinc salts that act as a protective barrier, insulating the underlying steel or iron from further corrosion.
Sacrificial Protection: Zinc is higher in the galvanic series than steel or iron. When these dissimilar metals with different electrical potentials come into contact, a galvanic cell forms. In this cell, the zinc anode corrodes preferentially, sacrificing itself to protect the steel or iron cathode from corrosion. This sacrificial action continues as long as there is zinc remaining in the coating, ensuring long-term corrosion protection.