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Microbiologically influenced corrosion of AISI type 304 stainless steels under fresh water biofilms
Author(s) -
George R.P.,
Muraleedharan P.,
Parvathavarthini N.,
Khatak H.S.,
Rao T.S.
Publication year - 2000
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/(sici)1521-4176(200004)51:4<213::aid-maco213>3.0.co;2-j
Subject(s) - biofilm , corrosion , chemistry , electrochemistry , nuclear chemistry , metallurgy , bacteria , materials science , biology , electrode , organic chemistry , genetics
The influence of biofilms formed by microorganisms on the corrosion behaviour of stainless steel (SS) in various fresh water environments was studied using electrochemical techniques. Biofilm characterization studies showed an algal‐dominated biofilm in the normal dark and light exposures, whereas, in the continuous dark exposures, bacterial‐dominated biofilm was observed. The open circuit potential (OCP) and the breakdown potential (E b ) of the specimens with biofilms showed a positive shift compared to those of the freshly polished specimens. Though ennoblement of breakdown potential showed protective nature of biofilm, ageing of the algal‐dominated biofilm was found to initiate localised corrosion of the substratum due to the heterogeneities in the biofilm, creating anodes and cathodes. In the case of specimens containing 123‐day old algal‐dominated biofilm, steady increase in current density was observed during polarization starting from OCP which is indicative of initiation and steady propagation of crevice corrosion.