The rusting of iron can be prevented by greasing, painting, galvanizing, anodizing, or oiling the surface. These methods can be classified into the following categories:
Galvanization: Galvanized metal is coated with a thin layer of zinc to protect it against corrosion. The zinc oxidizes when it is exposed to air creating a protective coating on the metal surface.
Alloying: It is the method of improving the properties of a metal by mixing the metal with another metal or nonmetal. When iron is alloyed with chromium and nickel in stainless steel is obtained. Stainless steel does not rust at all.
Painting: Rusting of iron can be easily prevented by coating the surface with paint which protects iron from air and moisture.
Greasing/Oiling: When some grease oil is applied to the surface of an iron object, then air and moisture cannot come in contact with it, and hence rusting is prevented.