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The first practical use of cathodicprotection is generally credited to Sir Humphrey Davy in the 1980s. Davy advice was sought by the Royal Navy in investigating the corrosion of cooper used for cladding the hulls naval vessels. Davy found that he could preserve copper in sea water by the attachment of small quantities of iron or zinc; the copper became, as Davy put it, >cathodically protected<.
The most rapid development of cathodic protection systems was made in the United States of America to meet the requirements of the rapidly expanding oil and natural gas industry which wanted to benefit from the advantages of using thin-walled steel pipes for underground transmission. For that purpose the metod was well established in the US in 1945.
Cathodic protection can, in principle, be applied to any metallic structure in contact with a bulk electrolyte. In practice its main use is to protect steel structures buried in soil or immersed in water. It cannot be used to prevent atmospheric corrosion. Structures commonly protected are the exterior surfaces of pipelines, ships hulls, jetties, foundation pilling, steel sheet-pilling, and offshore platforms. Cathodic protection is also used on the interior surfaces of water-storage tanks and water-circulating systems. Cathodic protection has also been applied to steel embedded inn concrete, to copper-based alloys in water systems, and, exceptionally, to lead-sheathed cables and to aluminium alloys, where cathodic potentials have to be very carefully controlled. |
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