LIU Guangzhou WANG Jianming ZHANG Jianqing CAO Chunan. EFFECT OF ELECTROLYTIC TREATMENT OF BALLAST WATER ON THE CORROSION BEHAVIOR OF 316L STAINLESS STEEL. Acta Metall Sin, 2011, 47(12): 1600-1604.
Abstract The introduction of invasive marine species into new environments by the ballast water of ships has been identified as one of the four greatest threats to the world’s oceans. Many technologies have been developed for ballast water treatment among which electrolytic treatment method has been taken as the most promising one. However, the corrosion problem of metals in treated seawater was seriously concerned by international maritime organization (IMO) and ship owners, especially the corrosion of 316L stainless steel which is widely used in the monitoring equipments of the ballast system of ships. In this study, the variation of environmental parameters of the seawater before and after electrolytic treatment was monitored. The corrosion behaviors of 316L stainless steel in both natural and treated seawater were investigated by electrochemical methods such as open–circuit potential (EOCP) measurements, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results showed that the pH value of the seawater increased and the dissolved oxygen content decreased slightly after electrolytic treatment, and the contents of dissolved organic carbon and particulate organic carbon decreased significantly in treated seawater. The corrosion test results showed that the resistance of 316L stainless steel to pitting corrosion was enhanced in treated seawater. Compared to the system in natural seawater, the open–circuit potential of the steel in treated seawater shifted about 0.4 V positively, and charge transfer resistance of the steel greatly increased. The breakdown potential of passivation films in treated seawater positively shifted more than 0.37 V. Our experimental results suggested that the corrosion resistance of 316L stainless steel in treated seawater was improved, which was ascribed to the thickening and compactness of the passivation film formed in treated seawater. It is safe for 316L stainless steel to be used in treated ballast water with the total residual chlorine (TRC) concentration of 9.50 mg/L.
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(刘光洲, 王建明, 张鉴清, 曹楚南. 金属学报, 2010; 46: 1093)
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