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Microbiologically influenced corrosion of steels by thermophilic and mesophilic bacteria
Author(s) -
AlfaroCuevasVillanueva R.,
CortesMartinez R.,
GarcíaDíaz J. J.,
GalvanMartinez R.,
TorresSanchez R.
Publication year - 2006
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/maco.200503948
Subject(s) - corrosion , mesophile , passivation , pitting corrosion , metallurgy , sulfate reducing bacteria , materials science , scanning electron microscope , polarization (electrochemistry) , thermophile , sulfate , anode , carbon steel , bacteria , chemistry , composite material , electrode , biology , genetics , layer (electronics)
Bacterial influenced corrosion of AISI 316 stainless steels (SS) and ASTM A36 carbon steel by two strains of sulfate reducing bacteria (SRB) were analyzed. Thermophilic and mesophilic bacteria were isolated from the condensate fluid of “Los Azufres”, a geothermal electric field located in the State of Michoacan at Central Mexico. Anaerobic corrosion tests were carried out for 15, 30 and 60 days in lactate‐containing media at 50 °C and 40 °C. Scanning electron microscopy (SEM) was used to determine corrosion morphology. Pitting density was determined with an optical microscope. Corrosion potential, anodic potentiodynamic polarization curves and pH values were measured under anaerobic conditions. Results show that the microbial activity influenced the overall corrosion process, whereas, pitting corrosion and localized attack corrosion (LAC) were found. The anodic polarization curves show that passivation and activation processes should take place on the steel surface of the sample and pH decreases as the exposure time increases.