Damage suffered by metals and alloys as a result of electrochemical and chemical reactions in mostly watery and gaseous environments is called corrosion. Most of the metals used in industry lose their stability in various environments including also atmospheric air and ground. Except for metals like gold and platinum found in a pure and stable state in nature, all metals are exposed to corrosion in the course of time as they are found in an oxidized state in nature.
It is a difficult process to separate metals from oxides and this process is performed with large quantities of raw material, energy and manpower. Therefore, the most widely used one of the methods used for preventing corrosion is protection against corrosion with paint as it shows high performance, it is aesthetical and easy-to-access.
Paints control corrosion as follows:
1 - They prevent water and oxygen from reaching the metal surface.
2 - Corrosion preventive pigments within them slow and stop corrosion. These pigments
- passivate the metal surface and
- perform alkali characteristics.
3 - They retard corrosion with galvanic effect. Metal dusts heavier than iron (zinc, lead, aluminum) can be used as pigment. They electrically contact with metal and slow corrosion as they have cathodic characteristics compared to iron.
When selecting paint, the following criteria are expected in terms of corrosion preventive and other characteristics:
- Resistance against abrasion
- Resistance against water, chemical substances and solvents
- Temperature resistance range
- Dry time
- Color and Glossiness Durability
- Decorative ability
- Camouflage and antiradar ability