TECHNOLOGIES
Cathodic Protection Modeling of Steels in Corrosive Chemical Environments Using COMSOL Multiphysics
This study investigates the electrochemical performance of Sacrificial Anode Cathodic Protection (SACP) systems for offshore steel structures using Finite Element Analysis (FEA). Two structural substrates, S235JR carbon steel and S550QL high-strength steel, were modelled in a 3 wt.% NaCl electrolyte. A comparative analysis was performed between two sacrificial anode materials: a conventional Al- 5Mg alloy and a quaternary Al-6Zn-0.2In-1Mg-0.03Ti alloy. The simulations evaluate the influence of anode placement errors by comparing an ideal symmetric distribution (90°) with a clustered configuration (10°). The results show that geometric clustering significantly alters the potential distribution along the structure. For S235JR steel, the clustered configuration produces localized underprotection with potentials reaching −0.78 V (vs. Ag/AgCl). In contrast, for S550QL steel, the same configuration results in localized over-polarization (≈ −0.96 V), thereby increasing the risk of hydrogen-induced stress cracking (HISC). The study demonstrates that improper anode placement may compromise cathodic protection efficiency even when high-performance anode alloys are used. These findings highlight the importance of accurate anode distribution and support the use of numerical simulations in digital twin approaches for offshore corrosion management.