Influence of sulfate-reducing bacteria on corrosion of 2205-type duplex stainless steel in chloride medium

P. J. Antony, R. K. Singh Raman, Shobhana Chongdar, Preadeep Kumar, R. Raman

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther

Abstract

Sulfate-reducing bacteria (SRB) play significant role in the corrosion of passivating materials like stainless steels. A detailed interpretation of the mechanism of interaction of biogenic sulfide with the passive film of stainless steel is scarce. In the present study coupons of solution-annealed 2205 type duplex stainless steel (DSS) were exposed to chloride medium containing SRB species, Desulfovibrio desulfuricans, and the corrosion damage was assessed by electrochemical and microscopic techniques. Etching of the duplex structure and crevice type attack were noticed in the case of coupons exposed for 40 days to SRB. There was no noticeable feature of corrosion on coupons exposed to sterile medium under identical conditions. The deterioration of passivity in the presence of SRB was also indicated during anodic polarization, by a sharp increase in the anodic current at potentials close to open circuit potential (E corr). The anodic limiting current density was determined to be an order of magnitude higher in the presence of SRB as compared to that for the specimen exposed to sterile medium. The corrosion damage observed on specimen exposed under freely corroding conditions to SRB for 40 days was more predominantly seen after an exposure to SRB for 14 days followed by anodic polarization. SEM studies of crevices observed after anodic polarization indicated that the attack was initiated at the grain boundaries and slowly encroached into austenite grains. ESCA studies reveal that SRB activity can modify the passive film through incorporation of sulphide ions in the film. The nature and mechanism of SRB attack on DSS are discussed.

Original languageEnglish
Title of host publication47th Annual Conference of the Australasian Corrosion Association 2007
Subtitle of host publicationCorrosion Control 2007
Pages511-517
Number of pages7
Publication statusPublished - 1 Dec 2007
EventAustralasian Corrosion Association (ACA) Conference 2007: Corrosion and Prevention - Sydney, Australia
Duration: 4 Dec 20075 Dec 2007
Conference number: 47th

Publication series

Name47th Annual Conference of the Australasian Corrosion Association 2007: Corrosion Control 2007

Conference

ConferenceAustralasian Corrosion Association (ACA) Conference 2007
Abbreviated titleCP 2007
CountryAustralia
CitySydney
Period4/12/075/12/07

Keywords

  • Crevice corrosion
  • Duplex stainless steels (DSS)
  • Passive film
  • Polarization
  • Sulfate-reducing bacteria (SRB)

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