Corrosion is the deterioration of a material, or of its properties, as a consequence of reaction with its environment. The direct and hidden costs of corrosion amount to billions of dollars per year throughout the world.

There are several schools of thought regarding the inclusion of the term "corrosion." Some would limit the term to the corrosion of metals, while others include the effects of soils, atmospheres, chemicals and temperature upon all types of materials. The need to understand and control corrosion has given rise to the new sciences of corrosion technology and corrosion control, both of which are solidly based upon chemistry.

The corrosion of metals is caused by the electrochemical transfer of electrons from one substance (oxygen for example) to another. This may occur from the surfaces of metals in contact, or between a metal and another substance when a moist conductor or electrolyte is present...