Corrosion (from lat. corrosio - corrosion) - spontaneous destruction of metals and alloys as a result of chemical, electrochemical or physico-chemical interaction with the environment. Destruction for physical reasons is not corrosion, but is characterized by the concepts of "erosion", "abrasion", "wear". The cause of corrosion is the thermodynamic instability of structural materials to the effects of substances in contact with them.