API 571 Certification (Corrosion & Materials) 2025 – 400 Free Practice Questions to Pass the Exam

The primary action of cathodic protection in corrosion mitigation is to convert the metal surface to a cathode in an electrochemical cell. When a metal structure, such as a pipeline or vessel, is made cathodic, it prevents the metal from corroding by reducing the oxidation reaction that causes corrosion.

In an electrochemical cell, corrosion typically occurs at the anode, where metal atoms lose electrons and dissolve into the electrolyte solution as metal cations. By applying cathodic protection, an external power supply or sacrificial anodes provides electrons to the metal surface, effectively shifting the electrochemical reactions. As a result, the metal surface becomes the site of reduction rather than oxidation, thus mitigating corrosion.

The other options do not accurately describe the main function of cathodic protection. Enhancing anodic reaction contradicts the purpose of cathodic protection, which is to inhibit such reactions. Protective coatings serve a different role by creating a barrier to moisture and corrosive elements, while the removal of contaminants is a maintenance practice that can aid corrosion control but does not constitute cathodic protection itself. Therefore, the correct focus is on the conversion of the metal surface to a cathode, which is fundamental in preventing corrosion through the principles of