Abriox

OVERVIEW

Cathodic protection (CP) is a technique to control the corrosion of a metal surface by making that surface the cathode of an electrochemical cell.

The first practical application of cathodic protection is generally attributed to Sir Humphrey Davy who, in the 19th century, improved the resistance of copper-clad ships to seawater corrosion by the attachment of small quantities of iron, zinc or tin. In the 20th century, particularly in the United States, the method was developed and, by 1945, had become the standard procedure for protection of metal pipelines as the oil and gas industries expanded rapidly.

The costs of laying a metal pipeline, determined by its specification, wall thickness and installation in the ground, are very high. Degradation of the material of the pipe is very expensive to correct and, at worst, can lead to a pipe failure with unpredictable consequences. Today, with its proven track record of maintaining pipelines over many decades, CP is well established. It is used on pipelines, other immersed or buried metal structures and in reinforced concrete to enhance resistance to corrosion. It enables thinner metal sheets or pipes to be used, thereby reducing costs.

Typical applications are to the external and internal surfaces of:

• Steel pipelines containing pressurised petrochemicals, gas or water

• Storage tanks

• Marine jetties

• Hulls of ships

• Steel pilings for bridges and buildings

• Subsea structures such as offshore platforms.