Cathodic Protection

Definition - What does Cathodic Protection mean?

Cathodic protection is a method by which pipelines are protected against corrosion by electric currents using cathodes. The pipe acts as a cathode of an electrochemical cell by discharging current from an external anode in order to make the current pass through the electrolyte directly to the anodic sites on the surface of the pipeline.

Cathodic protection applied to pipelines is very effective in keeping them from getting corroded and increasing its service life. Pipes made of metals such as copper, steel, lead, etc. that are subject to corrosive environment in soil or water can be protected against corrosion using this method.

Trenchlesspedia explains Cathodic Protection

Cathodic protection reduces the corrosion of metals to nil when supplied from an externally applied current or sacrificial anodes. The cathode is polarized in the negative direction from the corrosion potential when the external current is applied. This applied current is also known as protection current and in order to completely inhibit the corrosion process, the metal should be polarized to its reversible potential.

Cathodic protection systems can be a sacrificial anode or an impressed current system. In the sacrificial anode system, a less noble metal is coupled with the corroding metal to achieve protection from corrosion and the sacrificial anode also serves as a source of electrical energy. In the impressed current system, the corroding metal is polarized using external direct current by using it cathodically.

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