Cathodic protection is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. A simple method of protection connects the metal to be protected to a more easily corroded “sacrificial metal” to act as the anode.
Cathodic protection is often used to mitigate corrosion damage to active metal surfaces. Cathodic protection is used all over the globe to protect pipelines, water treatment plants, above and underwater storage tanks, ship and boat hulls, offshore production platforms, reinforcement bars in concrete structures and piers, and more.
In essence, cathodic protection connects the base metal at risk (steel) to a sacrificial metal that corrodes in lieu of the base metal. The technique of providing cathodic protection to steel preserves the metal by providing a highly active metal that can act as an anode and provide free electrons. By introducing these free electrons, the active metal sacrifices its ions and keeps the less active steel from corroding.