Biocorrosion characteristics of the copper alloys BFe30-1-1 and HSn70-1AB by SRB using Atomic Force Microscopy and Scanning Electron Microscopy

The biocorrosion susceptibility of copper alloys (HSn70-1AB and BFe30-1-1) in the culture media containing sulfate-reducing bacteria (SRB), enriched from a slurry of cooling tower in a power plant, was comparatively studied. Both Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were used to investigate the characteristics of biofilm, the adhesive forces of SRB cells on both types of copper alloys and the main chemical components on surfaces of both copper alloy coupons immersed in the media containing SRB. Results showed that BFe30-1-1 was more susceptible to SRB growth and bacterial adhesion than HSn70-1AB. The adhesive force of BFe30-1-1 substratum to SRB cells, both at periphery and on cellular surface, was greater than that of HSn70-1AB. At the same immersion time, the amount of S in the biofilm on BFe30-1-1 substratum was much higher than that on the HSn70-1AB. Data suggest that chemical composition of copper alloys affects the biofilm formation by SRB and also the chemical characteristics of the deposits on these alloys.