What is cathodic protection?

Cathodic protection is a method used to prevent corrosion of metal surfaces by converting the metal into a cathode in an electrolytic cell. By doing so, the corrosion process is inhibited, as it is the anodic areas of a metal that typically undergo oxidation and corrode. In this protective scheme, the structure to be safeguarded is connected to a more easily oxidized metal or an external power source which supplies negatively charged electrons, making it a cathode.

This process is especially important for infrastructure items like pipelines and storage tanks, where corrosion can lead to severe structural failures. By effectively making the target structure a cathode, the natural corrosion reaction is reversed, and instead of the metal dissolving away, the protective coating or connected anode corrodes instead, thereby prolonging the life of the metal structure.

Other options, such as galvanizing or painting, do provide some level of protection, but they operate through different principles and are not specific to the mechanism of cathodic protection. Converting a structure into an anode would actually promote corrosion, and merely painting surfaces without addressing underlying electrochemical processes wouldn’t provide the same level of protection against corrosion as cathodic protection does.