The influence of Bacillus subtilis on tin-coated copper in an aqueous environment.

The influence of Bacillus subtilis (BS) on tin-coated copper in an aqueous environment was investigated by exposing the sample to a culture medium inoculated with BS. Scanning electron microscopy, electrochemical measurements and chemical analyses were performed to study the corrosion mechanism. The experimental results show that BS can adhere and gather on the surface of the sample, resulting in oxygen consumption at the place where the bacteria are densely attached. Increases in the R ct values after the initial immersion showed that corrosion was inhibited, while decreases in the R ct values after the later immersion showed that corrosion was accelerated. Our results suggest that differences in oxygen concentration due to activity of BS are the main reason for corrosion of tin-coated copper.