Open AccessInfluence of Sulfate-Reducing Bacteria on the Corrosion Behavior of High Strength Steel EQ70 under Cathodic Polarization
Author(s) -
Fang Guan,
Xiaofan Zhai,
Jizhou Duan,
Meixia Zhang,
Baorong Hou
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0162315
Subject(s) - sulfate reducing bacteria , corrosion , electrochemistry , cathodic protection , electron transfer , sulfide , polarization (electrochemistry) , materials science , standard electrode potential , inorganic chemistry , electrode , chemistry , chemical engineering , metallurgy , sulfate , photochemistry , engineering
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 V SCE CP had a higher corrosion rate than that without CP, while EQ70 with -1.05 V SCE had a lower corrosion rate. The enhanced SRB metabolic activity at -0.85 V SCE was most probably caused by the direct electron transfer from the electrode polarized at -0.85 V SCE . This direct electron transfer pathway was unavailable in -1.05 V SCE . 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.