Cathodic protection is a method used to prevent corrosion of metal surfaces by making them the cathode of an electrochemical cell. It does this by applying an electrical current to the metal surface, which creates a protective oxide layer that prevents corrosion.

There are two main types of cathodic protection: galvanic and impressed current. Galvanic cathodic protection uses a less active metal as the anode to protect a more active metal as the cathode. Impressed current cathodic protection uses an external power source to apply a current to the metal surface.

The most common applications of cathodic protection include protecting underground pipelines, storage tanks, and marine structures such as ships and offshore platforms.

The key components of a cathodic protection system include the anode, cathode, power source, and control system. The anode is typically made of a less active metal, such as magnesium or aluminum, while the cathode is typically made of a more active metal, such as steel.

The benefits of cathodic protection include reduced maintenance and repair costs, increased lifespan of the protected structure, and improved safety by preventing corrosion-related accidents.

The basic steps in designing a cathodic protection system include determining the type of system required, assessing the condition of the metal to be protected, determining the location of the anodes and cathodes, selecting the appropriate power source, and designing the control system.