Cathodic Protection Criteria

Cathodic protection is a widely used metal corrosion control method. Most metals, when exposed to water or air, gradually corrode over time. This corrosion process weakens the metal structure, eventually rendering it unusable. In many industrial applications, this not only creates serious safety risks but also leads to significant maintenance and replacement costs.

Over the years, various methods have been developed to prevent the corrosion of metal pipes buried underground or submerged in water. One of the most common techniques is galvanic (sacrificial anode) cathodic protection, which is based on placing a more active metal in electrical contact with the structure to be protected. This sacrificial metal corrodes instead of the main structure.

Cathodic protection is used in many different fields, including but not limited to:

• Oil and gas pipelines
• Offshore and onshore drilling platforms
• Ship hulls to prevent rust and pitting
• Storage tanks, piers, jetties and other marine structures

The fundamental principle of cathodic protection is to transform the metal structure to be protected into the cathode of an electrochemical cell, thereby stopping or significantly reducing the anodic reactions occurring on its surface.

The main objective is to polarize the potential of the protected metal towards the open-circuit potential of the anode. To achieve this, a cathodic (negative) current is applied to the metal surface from an external source or sacrificial anodes, shifting its potential to a range where corrosion is minimized.