Final answer:
Corrosion is a galvanic process where metals deteriorate through oxidation, usually resulting in the formation of rust, tarnish, or patina. It is a redox process, and some metals are resistant to corrosion due to the formation of protective oxide films.
Step-by-step explanation:
Corrosion is a galvanic process by which metals deteriorate through oxidation, usually but not always to their oxides. It occurs when metals are exposed to air or other elements, resulting in the formation of rust, tarnish, or patina.
For example, iron rusts, silver tarnishes, and copper and brass develop a bluish-green surface called patina. Iron is one of the most commonly affected metals by corrosion, and it costs billions of dollars every year to replace corroded iron-containing objects.
Corrosion is a redox process where the oxidation of most metals is thermodynamically spontaneous. Some metals, however, are resistant to corrosion due to the formation of protective oxide films, such as aluminum, chromium, magnesium, nickel, and stainless steels that contain chromium and nickel.