Cathodic protection is a technique that involves applying a modest electrical voltage between a structure and the ground to stop exposed metal in that structure from oxidizing. It is a technique for shielding underground and submerged metallic structures against corrosion.
In general, all submerged or buried metal structures, including ships, offshore floaters, subsea equipment, harbors, pipelines, and tanks, are protected against corrosion using this protection.
What are the Basic Principles of Cathodic Protection?
The method relies on turning active regions of a metal surface into passive ones, effectively turning them into the cathode of an electrochemical cell. Learn more about corrosion and electrochemical cells.
The potential of the metal is decreased by the current supply, the corrosion attack stops, and cathodic protection is achieved. There are two ways to create this protection:
1. Protection from Cathodic Sacrificial Anodes
Connecting the metal to be protected with an anode made of a metal that corrodes more readily is the easiest way to perform cathodic protection. The metals that are frequently employed as anodes are zinc, aluminum, and magnesium. The least noble and most active metal serves as the anode to the others, sacrificing itself by corroding (giving up metal) in order to shield the cathode. Therefore, the name sacrificial anode. Sacrificial anodes need to be evenly distributed and placed near the area that has to be protected because their driving voltage is lower than impressed current anodes.
2. ICCP, Also Known as Impressed Current Cathodic Protection
ICCP systems rely on a regulated DC power supply, often known as a control panel, as an external source of electrical power. The current required to polarise the surface that has to be protected is supplied via the control panel. Specially created inert anodes are often made of conductive material that can support alternative anodic processes rather than simply dissolve into metallic ions to distribute the protective current.
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When is Cathodic Protection Obtained?
Cathodic safety Any metal that receives electricity will have its usual potential shifted to the negative. Steel is fully cathodic and protected by a voltage at a specific level.