Understanding of the corrosion behavior of a ductile cast iron exposed to the Thiobacillus ferrooxidans-inoculated medium using scanning vibrating electrode technique

Recently, the authors have demonstrated that iron-oxidizing bacteria have been shown to be involved in the severe corrosion of ductile cast iron pipes buried in acid-sulfate soils. However, direct evidence for the involvement of iron-oxidizing bacteria in corrosion processes has not yet well been clarified. In the present study, the involvement of iron-oxidizing bacteria in the corrosion of a ductile cast iron exposed to the Thiobacillus ferrooxidans (a species of iron-oxidizing bacteria) inoculated medium was examined by using scanning vibrating electrode technique (SVET) together with fluorescent microscope. It has been observed that the anodic regions correspond to the location of Thiobacillus ferrooxidans; providing further evidence that severe corrosion attacked regions can be caused by the action of Thiobacillus ferrooxidans in the initial stage of corrosion processes.