Corrosion can be defined as the degradation of a material when it comes in contact with the environment. The dissolving of a material by a corrosive liquid is called chemical corrosion. The material continues to dissolve until either it is consumed or the liquid is saturated. A simple example is salt dissolving in water. The removing of metal atoms from a solid material as the result of an electric circuit is called electrochemical corrosion. In this form of corrosion, metal atoms lose electrons and become ions thus forming a byproduct. Electrochemical corrosion occurs most frequently in aqueous mediums, in which ions are present in water or moist air. In this process, an electric circuit is created and the system is called an electrochemical cell. Corrosion of a steel pipe or a steel automobile panel, creating holes in the steel and rust as the byproduct, are examples of this reaction.

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