cathodic protection (CP)

A technique used to control corrosion of a metal structure or surface by introducing an anode to create an electrochemical cell in which the metal structure or surface to be protected is rendered the cathode. There are two types of systems for cathodic protection: sacrificial anode systems and impressed current systems. In each system, the anode possesses a lower electrochemical potential than the cathode (and is thus more corrodible), prompting the corrosion-causing current to flow away from the anode, rather than the cathode. For example, cathodic protection is used to control corrosion of boat hulls, underground storage tanks, home water heaters, and steel water and fuel pipelines. In some industries, governments require regular testing and inspection of cathodic protection systems to ensure proper operation.