Final answer:
Ferrous metals are protected from corrosion by protective coatings such as chromium plating and galvanization with zinc, forming a zinc layer. Stainless steel's chromium content forms a passivate oxide layer, and cathodic protection with metals like zinc and magnesium provides additional safeguards.
Step-by-step explanation:
To treat ferrous metals for corrosion, various methods are used to prevent oxygen and water from causing oxidation. Prophylactic Protection, such as applying a protective coating is one of the most common techniques used. For instance, a thin layer of chromium applied by an electrolytic process is used for parts such as faucets and automobile exteriors, whereas tin is used for steel cans, both forming protective oxide coatings. Galvanization is another method where a layer of zinc is applied to protect the underlying iron.
Additionally, alloying iron with other metals can significantly increase resistance to corrosion. Stainless steel is a prime example of this, as it contains a small amount of chromium which forms a passivate oxide layer, protecting the iron. Furthermore, cathodic protection can be employed by attaching more readily oxidizable metals like zinc or magnesium to iron surfaces, acting as sacrificial anodes.