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Cathodic Protection in Practice

Cathodic Protection in Practice February 17, 2015

Practice the use of cathodic protection was first performed by Sir Humphrey Davy in 1820. davy advice was sought by the Royal Navy in investigating corrosion of copper sheeting used for cladding the hulls of naval vessels. Davy discovered that copper in sea water can be maintained with added small amounts of iron or zinc. So that the copper to be something davy say that "cathodic protection".

Cathodic protection system experiencing the most rapid growth is the cathodic protection system created by the United States. rapid growth is due to the needs of the oil and gas industry that is growing and want to benefit from the use of thin-walled steel pipe for underground transmission. because of the very rapid development, this method is well established in the United States in 1945.

In the united kingdom, which is widely used is a low-pressure Thicker-walled cast-iron pipes. Cathodic protection system is still very little applied until the early 1950s. The increase of the use of cathodic protection system takes place when the method used from 1952 have been successful to protect approximately 1000 miles of Wartime full-line network that has been placed between 1940 and 1944. And so far, this method has been well established.

In its principle, cathodic protection system can be applied to the metal structure associated with the bulk electrolyte. In practice its main use is to protect steel structures buried in the ground or immersed in water. It can not be used to prevent atmospheric corrosion.

Generally, the structure of which is often protected is the exterior surface of the pipe, ship hulls, docks, foundation piling, steel sheet-piling, and offshore platforms. Cathodic protection is also used on the interior surface of the water storage tank and circulating water system. However, due to the external anode protection will rarely spread to a distance of more than two or three pipe diameters. This method is not suitable for the protection of small-bore pipework. Cathodic protection has also been applied to steel embedded in concrete, to copper-based alloys in water systems, and, exceptionally, to lead-sheathed cables and to aluminum alloys, where cathodic potentials have to be very carefully controlled.