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

How done

This is achieved by placing in contact with the metal to be protected another more easily cororded metal to act as the anode of the electrochemical cell.

Uses

Cathodic protection systems are most commonly used to protect steel, water/fuel pipelines and storage tanks; steel pier piles, ships, offshore oil platforms and onshore oil well casings.

In elctrical generating stations using condensers in steam turbine exhaust, a similar system is used to protect tube ends in water boxes.

Other uses

Cathodic protection can be, in some cases, an effective method of preventing stress corrosion cracking.

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