The influence of sulfate-reducing bacteria on the passivity of type 317L austenitic stainless steel
- State Univ. of New York, Stony Brook, NY (United States). Dept. of Materials Science and Engineering
The influence of sulfate-reducing bacteria (SRB) on the passivity of a Mo-bearing austenitic stainless steel (SS), type 317L, was investigated using X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. Samples were exposed to a SRB culture, and then resultant surface states were analyzed by XPS and corrosion resistance by cyclic polarization in deaerated 0.1 M HCl. Passivity of the SRB-exposed samples was further studied by XPS after polarization at a passive potential ({minus}160 mV{sub SCE}) in 0.1 M HCl. The samples were characterized under two surface conditions: unrinsed and rinsed with deaerated alcohol and deaerated deionized water. Control samples were exposed to uninoculated medium and as-polished coupons provided baseline for comparison. The following sulfides were formed during the exposure: FeS, FeS{sub 2}, MoS{sub 2}, Cr{sub 2}S{sub 3}, NiS, and possibly Fe{sub 1{minus}x}S. These sulfides were mainly in the outer layers of the surface so that the passive film was not markedly deteriorated. In addition, a Mo(V) species was formed in the biofilm and increased the passivity by: (1) reducing the bacterial activity and sulfate reduction through formation of molybdate and (2) forming a Mo(v) species which is insoluble in 0.1 M HCl.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 653346
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 6 Vol. 145; ISSN JESOAN; ISSN 0013-4651
- Country of Publication:
- United States
- Language:
- English
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