Cathodic Protection and Prevention: Principles, Applications and Monitoring

Cathodic protection (CP) has a long story. Alessandro Volta firstly made an indirect mention few years after his pile’s invention. In a paper to the editors of the Swiss magazine, «Bibliothècque Britannique», dated 1802, he wrote “[. . .] oxidation decreases if the current passes from the solution to the metal even to the point of extinction where hydrogen is evolved. [. . .]”,1 which is the description of the effects of CP. A few years later, Humphrey Davy in 1806 mentioned the same effects as Volta did, and definitely in 1824 described its application to the hull of ships of Royal Navy.2 CP officially was born. That experience was considered unhappy so remained dormant for a century. Only after World War II, CP application started and spread largely in industry. Despite the Davy’s experience, CP has proved in last 70 years that it works in a variety of applications, from soil and seawater, to concrete, on either active and passive metals. Nevertheless, how it really works is still under debate whether protection is a matter of thermodynamics or kinetics.