Microbial corrosion of aluminium alloys in mine water
No Thumbnail Available
Date
2016-08-16
Authors
Bondanno, Angela
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Since aluminium alloys are being considered for more extensive use in the mining industry, their
susceptibility to corrosion in these environments should be determined. Various aluminium alloy
samples, from in situ test rigs on two South African mines, were examined. It was found that their
surfaces were colonised by a variety of microorganisms including sulphate reducing bacteria and
Pseudomonas spp, Pitting and intergranular corrosion Were the main forms of attack.
Immersion and electrochemical tests were car. jed out in mine water under both static and flow
conditions. Aluminium alloys 1070, 5182,6063 and 6261 were exposed to cultures of Desulfovibrio
desulfuricans, Pseudomonas aeruginosa and a mixed strain of sulphate reducing bacteria. Conversion
coated and anodized samples were tested under flow conditions only.
The presence of sulphate reducing bacteria in mine water presented an aggressive environment for
aluninium alloys leading to pitting at alloying inclusions and intergranular attack. The involvement
of FeS in the corrosion process was established. The alloys exposed to Pseudomonas cultures also
underwent pitting corrosion. Anodizing and conversion coating were effective as temporary rneasures
against microbially induced corrosion provided no defect or damage was present. The alloys
were not recommended for use in mine waters
Description
A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand,
Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering.
Johannesburg, 1990