200 Years On: Sir Humphry Davy and Cathodic Protection

The science and practical application of cathodic protection (CP) now has a 200 y history and today successfully protects a vast array of infrastructure worldwide from the destructive actions of corrosion. It all started in 1824 with the initiation of work by Sir Humphry Davy as president of the Royal Society of London and three extraordinary papers concerning his work, funded by the British Admiralty, on the protection of copper sheeting on ships of war and other ships from corrosion. Davy applied his knowledge, experience, and meticulous scientific method to understanding the cause of the corrosion and reasons why corrosion can be mitigated by electrochemical means. There has been a historic misunderstanding of the adverse effects concerning the increase of marine fouling on some ships and consequently insufficient attention given to the precise nature of Davy’s research, his ready recognition of the effect of excessive calcareous deposits upon marine fouling in some circumstances and his work to rectify the issue. Many of the ships to which Davy’s CP was applied returned from journeys free from fouling and always with the copper intact. This paper looks at the science within Davy’s publications, addresses criticisms, and shows that it was a loss in the Admiralty’s support after just 2 y that curtailed further research by Davy and his assistant Michael Faraday into the refinement of the technique and application to other metals at the time.