Influence of Sulfate-Reducing Bacteria on Corrosion Behavior of EQ70 High-Strength Steel

This work examines corrosion behavior of EQ70 high-strength steel under anaerobic conditions in artificial seawater containing sulfate-reducing bacteria (SRB). Polarization and electrochemical impedance spectra (EIS) tests were conducted. The results reveal that corrosion rate initially decreased at the beginning of immersion. However, as the immersion time progressed, the corrosion rate of the high-strength steel increased, attributed to SRB reproduction. The scanning electron microscopy (SEM) results demonstrate that the corrosion was more severe in artificial seawater containing SRB compared to that of seawater without SRB. The morphologies of confocal laser scanning microscopy (CLSM) demonstrate that, after 15 days of immersion, the average depth of the corrosion pits on the sample in the artificial seawater containing SRB was nearly double that of the sample in the SRB-free seawater.