Corrosion Behavior of DH36 Steel in the Presence of Acid-Producing Bacterium Citrobacter farmeri

The work aims to provide a basic knowledge of corrosion behavior and corrosion kinetics of ocean engineering steel DH36 induced by Citrobacter farmeri. This study analyzed the corrosion product composition, corrosion morphology, electrochemical information, and weight loss of DH36 in various corrosion systems. The results indicated that with the extension of soaking time, the corrosion products soaked in Citrobacter farmeri suspension were denser than those soaked in artificial seawater. The initial immersion stage led to a higher uniform corrosion rate of DH36 in C. farmeri suspension compared to in artificial seawater, which subsequently decreased over time. DH36 experienced primarily uniform corrosion when immersed in artificial seawater. In contrast, DH36 samples in C. farmeri suspension exhibited significant crevice corrosion, resulting in a maximum pit depth of 5.720 μm. Furthermore, the weight loss of DH36 in artificial seawater and C. farmeri suspension could be described by the power function formula D = 0.0006t0.9579 and D = 0.0007t0.7247, respectively. This study elucidates the fundamental mechanisms through which the presence of C. farmeri induces general and pitting corrosion of DH36 in a marine environment.