Maruthamuthu, S. and Nagendran, T. and Anandkumar, B. and Karthikeyan, M.S. and Palaniswamy, N. and Narayanan, G. (2011) Microbiologically influenced corrosion on rails. Current Science, 100 (6). pp. 870-880. ISSN 0011-3891

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Abstract

Corrosion of rails has been a cause of concern for the Southern Railways. Out of many causes, corrosion due to toilet droppings is more pronounced. In this study, the role of bacteria, viz. heterotrophic bacteria, manganese oxidizers, iron bacteria and ureolytic bacteria on rails have been studied. The attachment of rod- and cocci-shaped bacteria were noticed on the corroded rail sample. A porous rust layer and fine cracks were noticed on the steels. Twenty bacterial strains were identified by molecular technique and most of the bacteria were positive in citrate and urease test, where 85% species could tolerate high pH 9.0. X-ray photoelectron spectroscopy revealed that FeOOH in the bare steel was converted to ferric oxides and hydroxides due to bacterial corrosion. When the rail sample was tested at low AC perturbations, the biofilm provided protection to the rails. However, at higher anodic potentials, the biofilm was not able to protect the bare material. It could be assumed that the ureolytic bacteria and iron/manganese oxidizers may create differential pH gradient on the metal surface which enhances the electrochemical reaction of the metal surface.

Item Type:	Article
Uncontrolled Keywords:	Atmospheric corrosion; bacterial corrosion; rail corrosion; ureolytic bacteria
Subjects:	Microbiolcorrosion Corrosion Science and Engineering
Divisions:	UNSPECIFIED
Depositing User:	Dr. N Meyyappan
Date Deposited:	01 Jan 2014 11:54
Last Modified:	01 Jan 2014 11:54
URI:	http://cecri.csircentral.net/id/eprint/3066

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