Nickel is highly resistant to corrosion or rusting. However, when exposed to excessive humidity, nickel does corrode. When exposed to oxygen and moisture, nickel forms a thin layer of greenish colored nickel oxide. In an acidic environment, nickel begins to rust too.
Rusting of nickel is very slow. The thin film of nickel oxide can be removed by scrubbing, which exposes a clean layer of the metal.
The corrosion-resistant quality of nickel is useful in metallurgy. Nickel is often plated over other ferrous metals that rust easily. Ferrous metals contain iron and form iron oxide (or rust) when exposed to atmospheric oxygen.
Rusting of metals destroys the metals and causes metal fatigue.