AMPP Cathodic Protection Technician (CP2) Practice Exam 2025 – All-in-One Resource to Master CP2 Certification

The correct response highlights the concept of activation polarization, which occurs at the interface between a structure (like a metal) and the electrolyte (like soil or water) during electrochemical reactions. This phenomenon arises when there is a delay or hindrance in the electron transfer process, which is essential for an electrochemical reaction to proceed.

At the structure/electrolyte interface, the activation energy needed for the electrochemical reactions involves the transfer of charge. This energy barrier can lead to a potential drop, which is represented as activation polarization. Essentially, it is the effect observed when the current flow is impeded due to the time it takes for electrons to be transferred, resulting in an increase in the overpotential.

The significance of activation polarization in cathodic protection systems is noteworthy because it can directly impact how well protection systems function. If the activation polarization is too high, the protection may be less effective because it could inhibit the desired electrochemical reactions that protect the metal from corrosion.

The other concepts relate to various scenarios of polarization but do not specifically address the charge transfer aspect as activation polarization does. Concentration polarization, for instance, pertains to changes in concentration of reactants or products near the electrode surface, while mixed polarization combines both activation and concentration effects