Corrosion control

Chemical or electrochemical attack suffered by metals when they are exposed to air, water or soil is known as corrosion. There can be types of corrosion- dry corrosion and wet corrosion. The main reasons for dry corrosion are oxidation, corrosion by gases and liquid metal corrosion. Wet corrosion is classified into seven types. They are galvanic corrosion, concentration corrosion, pitting corrosion, waterline corrosion, stress corrosion, intergranular corrosion and fatigue corrosion. Various factors affect corrosion. These factors are electrode potentials, hydrogen overvoltage, impurities, pH of the medium, temperature, oxygen environment, humidity etc. By suitable coating methods we can control corrosion. We can employ metal coating, inorganic coating and organic coating. Different metal coating techniques are hot dipping, cladding, spraying, cementation and electroplating.