
176 Engineering Materials Technology
Metallic coatings can be applied to metals to protect them by electro-
chemical action. The coating used can achieve corrosion resistance by being
either a less noble or sacrificial metal or a more protective, more noble metal.
Anode Cathode
V
)
zinc
Steel
Figure 9.8 Galvanized steel
Zinc is less noble than steel and thus can be used to give sacrificial
protection. Steel components can be protected by dipping them in molten zinc
to form a thin surface coating of zinc on the steel surface. This method is
known as galvanizing. The zinc acts as an anode with the steel being the
cathode (Figure 9.8), and the