Corrosion Behavior of Type 304 Stainless Steel in a Simulated Seawater-Based Medium in the Presence and Absence of AerobicPseudomonasNCIMB 2021 Bacteria

Abstract

A comparative study of the corrosion behavior of type 304 stainless steel (304 SS) in a nutrient-rich simulated seawater-based medium in the presence and absence of a marine aerobic Pseudomonas NCIMB 2021 bacterium was carried out. Electrochemical studies (including Tafel plots and electrochemical impedance spectroscopy) revealed that 304 SS underwent different corrosion processes under the attack of Pseudomonas bacteria. In the absence of the Pseudomonas bacterium, the passivating film on 304 SS remained relatively stable, and the anodic reaction was under diffusion control. Colonization of the Pseudomonas biofilm on the coupon surface led to the acceleration of corrosion rates and a dramatic decrease in resistance of passivating film due to localized breakdown of the film. Scanning electron microscopy (SEM) results revealed an increase in heterogeneity and coverage of the biofilms of Pseudomonas bacterium with exposure time. Extensive micropitting corrosion underneath the biofilms was also observed, in ...