Influence of cathodic protection potential on the efficiency of steel protection in marine sediments containing sulfate-reducing bacteria

This study investigates the effects of different cathodic protection potentials on SRB adhesion and corrosion product formation in marine sediment containing sulfate-reducing bacteria (SRB), using weight loss measurements, surface morphology analysis, corrosion product characterization, and electrochemical testing. The results show that SRB form biofilms on the cathodic surface, which promote the formation of corrosion films. These films provide a certain degree of protection to the metal, and their composition changes with the applied potential. The efficiency of cathodic protection is jointly influenced by the protection potential and SRB activity. The study demonstrates that appropriately shifting the cathodic protection potential in the negative direction can suppress SRB activity while utilizing its role in promoting corrosion film formation, thereby enhancing protection performance. In actual marine environments, a suitably negative cathodic protection potential can both inhibit SRB and improve protection efficiency by facilitating corrosion film formation. • Investigated SRB adhesion on anode and cathode surfaces under various CP potentials in marine sediment. • Demonstrated that SRB biofilm promotes corrosion film formation, which enhances metal protection. • Explored the interaction between microbial adhesion and ICCP efficiency in marine sediment. • Proposed a strategy using SRB-induced corrosion films and CP potential regulation to mitigate MIC.