Corrosion of high carbon steel by bacteria under aerobic and anerobic conditions
Date
2018-02
Authors
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Journal ISSN
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Publisher
Federal University of Technology, Owerri
Abstract
The role of bacteria in the corrosion of high carbon steel under aerobic and anaerobic conditions was investigated using sulphate reducing bacteria and other aerobes. The microbes isolated from the soil included; aerobes (Bacillus species, Pseudomonas species) and anaerobes (Desulfovibriospecies, Thiobacillusspecies). The role of bacteria in the corrosion of high carbon steel was estimated using the weight loss technique and the electrochemical potential measurement technique. Eighteen samples of a high carbon steel of known compositions were exposed to sulphate reducing bacteria under different environments (aerobic, anaerobic and control). The physical and chemical changes were examined and monitored on weekly basis for six weeks. It was observed that the coupons immersed in the media with sulphate reducing bacterium underwent fast activation and numerous corrosion sites were formed on the surfaces. The average corrosion rate for six weeks (42 days) period of time as determined by the weight loss method and electrochemical testing were found to be 0.0004595mm/year, -0.712mV in aerobic environment, 0.0005646mm/year, -0728mV in anaerobic environment and 0.0004458mm/year, -0702mV in the control or reference environment (distilled water environment). High carbon steel was found to corrode more only in the anaerobic environment. In view of this, high carbon steels were found to be relatively more corrosion resistant than mild and medium carbon steels and may be suitable for application in industries such as the petrochemical industry.
Description
This is for the award of Masters of Science (MSc.) Degree in Environmental Microbiology
Keywords
Bacillus species, pseudomonas species, desulfovibriospecies, thiobacillusspecies, Department of Microbiology
Citation
Nwokorie, R. C. (2018). Corrosion of high carbon steel by bacteria under aerobic and anerobic conditions [Unpublished Masters Thesis]. Federal University of Technology, Owerri, Nigeria