Influence of Sulfate-Reducing Bacteria on the Corrosion Behavior of High Strength Steel EQ70 under Cathodic Polarization.
Certain species of sulfate-reducing bacteria (SRB) use cathodes as electron donors for metabolism, and this electron transfer process may influence the proper protection potential choice for structures. The interaction between SRB and polarized electrodes had been the focus of numerous investigations. In this paper, the impact of cathodic protection (CP) on Desulfovibrio caledoniens metabolic activity and its influence on highs trength steel EQ70 were studied by bacterial analyses and electrochemical measurements. The results showed that EQ70 under -0.85 VSCE CP had a higher corrosion rate than that without CP, while EQ70 with -1.05 VSCE had a lower corrosion rate. The enhanced SRB metabolic activity at -0.85 VSCE was most probably caused by the direct electron transfer from the electrode polarized at -0.85 VSCE. This direct electron transfer pathway was unavailable in -1.05 VSCE. In addition, the application of cathodic protection led to the transformation of sulfide rusts into carbonates rusts. These observations have been employed to provide updated recommendations for the optimum CP potential for steel structures in the presence of SRB.
Marine Corrosion and Protection Centre, Institute of Oceanology, Chinese Academy of Sciences, No. 7 Nanhai Road, Qingdao, 266071, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
Fang
F
Guan
Marine Corrosion and Protection Centre, Institute of Oceanology, Chinese Academy of Sciences, No. 7 Nanhai Road, Qingdao, 266071, China.
Xiaofan
X
Zhai
Marine Corrosion and Protection Centre, Institute of Oceanology, Chinese Academy of Sciences, No. 7 Nanhai Road, Qingdao, 266071, China.
Jizhou
J
Duan
Marine Corrosion and Protection Centre, Institute of Oceanology, Chinese Academy of Sciences, No. 7 Nanhai Road, Qingdao, 266071, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
Meixia
M
Zhang
Marine Corrosion and Protection Centre, Institute of Oceanology, Chinese Academy of Sciences, No. 7 Nanhai Road, Qingdao, 266071, China.
Baorong
B
Hou
D003343:Corrosion; D003470:Culture Media; D058266:Dielectric Spectroscopy; D055664:Electrochemical Techniques; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D013232:Steel / Q000737:chemistry*; D016999:Sulfur-Reducing Bacteria / Q000378:metabolism*; D013499:Surface Properties; D013997:Time Factors
D003470:Culture Media; D013232:Steel; D007501:Iron