
According to the Deutsches Institut für Normung (DIN) also known as German Institute of Standardization, corrosion is the physical interaction between a metal and its environment that results in changes of the metal's properties and which may lead to significant functional impairment of the metal, the environment or the technical system of which they form a part. Corrosion damage is a phenomenon that causes impairment of the metal function, environment or the technical system. Corrosion damage is characterized by the complete loss of operational capability of the technical system. Corrosion doesn't occur as linear abrasion, but in versatile forms of appearance. It is mainly caused due to the environmental factors which include air, soil and water. Corrosion protection is therefore needed to minimize the expenses for costly repetitive maintenance measures. Corrosion protective coatings are therefore used to avoid protect metal from degradation due to moist air, oxidation, salt spray and exposure to various industrial and environmental chemicals.