EFFECT OF METAL SUBSTRATE ON INITIAL ATTACHMENT OF E. COM BACTERIA AND SUBSEQUENT MICROBIOLOGICALLY INFLUENCED CORROSION

摘要

It is well known that the rate and form of corrosion in a particular environment can vary substantially for different types of metals. The type of metal can also influence the attachment of microorganisms and may increase or decrease susceptibility to microbiologically influenced corrosion (MIC). In the present study, the influence of metal type on the initial attachment of bacteria and subsequent MIC was investigated for carbon steel, stainless steel and copper. As a model system, finely polished coupons were exposed to E. coli bacteria in a minimal medium. A range of techniques including 3D optical profilometry, light microscopy and scanning electron microscopy (SEM) were used to study the bacterial attachment and subsequent corrosion of metal coupons tested. The results indicate that the initial attachment of bacteria was different over different types of metal coupons tested with maximum attachment observed on the carbon steel coupons. Longer term immersion studies showed accelerated corrosion of carbon steel and copper in biotic conditions, whereas no difference in corrosion was observed for stainless steel under both abiotic and biotic conditions. The overall results showed that the metal type had a significant impact on the initial attachment of bacteria and resulting MIC.