Cathodic protection principles

The basic corrosion features of corrosion phenomena and the cathodic protection (CP) principles that are obtained from corrosion literature is explained. Cathodic protection is a process of reducing or eliminating corrosion by making the metal a cathode by means of direct current (DC). The cathode is the electrode where the reduction occurs. DC electricity is associated with the corrosion process on a buried or submerged metallic structure. The DC flows through the anodic areas into the soil, and then through the soil and onto the cathodic areas, and back to the pipe to complete the circuit. The corrosion occurs where the current discharges from metal into the soil at the anodic areas. The CP current is required to flow through a conditioning environment onto a metallic surface that is being protected. Special types of corrosion protection systems can be used, where special problems are encountered.