| MAO Xiaomin,GUO Na,SUN Zhenmei,GUO Zhangwei,HUAG Shiyu,LIU Tao.Corrosion Behavior of Marine EH 40 Steel by Polar Cryogenic Microorganisms[J],54(4):70-81 |
| Corrosion Behavior of Marine EH 40 Steel by Polar Cryogenic Microorganisms |
| Received:March 19, 2024 Revised:May 31, 2024 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2025.04.005 |
| KeyWord:polar areas pyschrophile corrosion by microorganisms pitting corrosion |
| Author | Institution |
| MAO Xiaomin |
Shanghai Maritime University, Shanghai , China |
| GUO Na |
Shanghai Maritime University, Shanghai , China |
| SUN Zhenmei |
Shanghai Maritime University, Shanghai , China |
| GUO Zhangwei |
Shanghai Maritime University, Shanghai , China |
| HUAG Shiyu |
Shanghai Maritime University, Shanghai , China |
| LIU Tao |
Shanghai Maritime University, Shanghai , China |
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| Abstract: |
| In recent years, the significance of polar resources and shipping routes has increasingly come to the forefront, bringing attention to the issue of ship navigation safety in polar environments. When ships navigate through polar seas, they experience significant friction with ice, leading to the shedding of surface coating and direct exposure of matrix steel to seawater. The effect of polar microorganisms in sea ice water on the corrosion of ship steel is a significant yet understudied factor. These microorganisms may have a unique accelerating effect on the corrosion behavior of marine steel due to the particularity of the polar environment. The microorganisms may secrete specialized corrosion media or form distinct biofilms on the surface of steel, thereby expediting the corrosion process. In this study, two typical microorganisms (Psychrobacter cibarius and Halomonas meridiana) found in polar sea ice water were selected. Characterization techniques such as scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS) were employed to investigate the corrosion behavior of EH 40 marine steel in these two pyschrophile. Based on the findings from LSCM and SEM, H. meridiana was found to be uniformly and continuously distributed across the sample surface, resulting in the formation of a corrosion product film consisting of iron oxides, bacteria, and their exocrine secretions. The flatness and density of this film were observed which were higher compared to those of the corrosion product film formed by P. cibarius on the sample surface. The results of electrochemical impedance and polarization indicated that the charge transfer resistance varied with the formation and shedding of corrosion product film. The corrosion product film on the surface of P. cibarius exhibited greater instability, leading to a decrease in charge transfer resistance in the later stage. In contrast, H. meridiana demonstrated stable growth, higher impedance value, and lower corrosion current throughout the experiment. Moreover, the weight loss rate was found to be significantly elevated in the abiotic seawater medium, whereas H. meridiana demonstrated a comparatively reduced weight loss rate compared to P. cibarius. At 4 ℃, and significant pitting occurred on the samples in the control culture medium, while the P. cibarius group exhibited a relatively mild degree of pitting with small pits, and no discernible pitting was observed on the surface of the H. meridiana group. This phenomenon was attributed to the corrosion product films formed by these two bacteria on the sample surfaces. The soluble polysaccharide secretion of the two strains was quantified, with H. meridiana secreting a total content of 5.669 mg/g and P. cibarius secreting 4.980 mg/g. The soluble polysaccharide content of H. meridiana exceeded that of P. cibarius. In summary, the pitting sensitivity of EH 40 was found to be higher at 4 ℃, leading to severe pitting in abiotic seawater medium. Both strains of pyschrophile exhibited adhesion to the surface of EH 40 steel, resulting in the formation of a biofilm with certain protective properties. Notably, H. meridiana demonstrated greater secretion of soluble polysaccharides and displayed more uniform and continuous bacterial adhesion. Consequently, the biofilm formed on the sample surface was more compact and exhibited a superior protective effect compared to that formed by P. cibarius. |
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