CORROSION AND CATHODIC PROTECTION OF METALS
In general terms, corrosion can be defined as a gradual wear, decay by chemical reactions. Corrosion can also be defined as the deterioration of metals other than mechanical means. Thus, the metal returns to its natural state. This results in mass loss of the metal. Iron and steel generally corrode in the presence of oxygen and water. The rate of corrosion varies according to ambient conditions. For example, the velocity or acidity of water in water increases with the movement of metal, with an increase in temperature or aeration, with the presence of certain bacteria or other influential factors. On the other hand, corrosion can be delayed by some protective layers or films. The alkalinity of water also reduces the rate of corrosion on metallic surfaces.