Influence of streptomyces on the corrosion behavior of steel A3 in Thiobacillus ferrooxidans media

The electrochemical measurement and surface analysis methods were carried out to investigate the corrosion behavior of steel A3 in Thiobacillus ferrooxidans, streptomyces and T. f-streptomyces mixed colony systems. Results showed that asymmetric biofilms adhered on the surface of steel A3 after 7 days of exposure in different corrosive systems; pitting corrosion occurred on the surface of steel A3 after 7 days of exposure in T. f and streptomyce solutions, but an even corrosion appeared in T. f-streptomyces mixed colony solution; weight loss in the mixed colony system was between those caused by each individual microorganisms; the electrochemical impedance spectroscopy results indicated that the impedance value of steel A3 in the mixed colony system was the medium of those in T. f and streptomyces system. Above results revealed that the most serious corrosion occurred in the streptomyces system, secondly for the T. f-streptomyces mixed colony solution, and corrosiveness of the T. f solution was the lightest to steel A3.