2006 Volume 92 Issue 4 Pages 280-286
The authors have been applying a microbial metabolic reaction that induces Microbiologically Influenced Corrosion (MIC) to develop a biological metal etching process (Bio-etching). Some kinds of bacteria that have the ability to induce corrosion on metals were detected through MIC failure case analysis. For example, Staphylococcus sp. is known to be able to induce corrosion on copper.
The mechanism of MIC of copper, related to Staphylococcus sp., is described in the following. First, the adhesion of Staphylococcus sp. on the surface of copper takes place. The bacteria then multiply and begin to form small patch colonies. At this point lactic acid, related to the beginning of the MIC process of copper, is produced. With further bacterial multiplication a bio-film is formed on the surface of copper and ammonia, which has a strong causticity to copper, is also produced, showing that further corrosion of the copper surface takes place.
In this paper, a study has been performed to investigate the effective application of the metabolic reaction of Staphylococcus sp. to bioetching, by forcing microorganism to stick to the materials. It was confirmed that the formation speed of the adhesion area on copper, which has antibacterial function, had improved and that the processed area of the target zone could be defined with good accuracy. It was also observed that the corrosion takes place only in the small areas not covered by the protection resist. These results show that Bio-etching of metallic copper by Staphylococcus sp. is a very effective process.