How can cathodic protection be achieved?

Cathodic protection is an essential technique used to prevent corrosion on metal surfaces, particularly in marine environments. It is accomplished primarily through two methods: sacrificial anodes and impressed current systems.

Using sacrificial anodes involves attaching a more electrochemically active metal, like zinc or aluminum, to the structure being protected. This anode will corrode preferentially, sacrificing itself to protect the underlying metal. The idea is that the sacrificial metal will corrode instead of the protected metal surface, which slows down the overall corrosion process.

Impressed current systems, on the other hand, use an external power source to provide a continuous flow of current that neutralizes the corrosive electrochemical reactions occurring on the metal surface. This method is often applied in larger structures, such as offshore oil rigs or ship hulls, where a more controlled and robust protection method is necessary.

The other methods listed—painting the surface, applying heat, and increasing the thickness of the metal—do not provide the electrochemical necessary means to address corrosion in the same direct way that cathodic protection does. While painting can serve as a barrier to moisture and reduces environmental exposure, it does not provide the same level of protection as cathodic methods. Heat application affects the