Cathodic protection is a corrosion control method used to safeguard metal structures, such as pipelines, storage tanks, or offshore platforms, from deteriorating due to corrosion. It involves making the structure the cathode in an electrochemical cell to prevent its corrosion.
There are two primary types of cathodic protection:
- Galvanic Cathodic Protection: This method uses sacrificial anodes made of a more reactive metal, like zinc or magnesium, connected to the structure. These anodes corrode sacrificially instead of the protected metal, effectively preventing the corrosion of the structure.
- Impressed Current Cathodic Protection: In this technique, an external power source supplies a controlled electrical current to the structure to polarize it and prevent corrosion. Typically, inert anodes made of mixed metal oxides are used, and the current is adjusted to maintain the desired level of protection.
Both methods function by ensuring that the structure to be protected becomes the cathode in the electrochemical cell, halting the corrosion process. Cathodic protection is widely used in industries where metal structures are exposed to harsh environments, significantly prolonging their lifespan and reducing maintenance costs associated with corrosion-related damage.