Microbiologically Influenced Corrosion (MIC)
Microorganisms -- whether they be microalgae, bacteria, or fungi -- can cause microbiologically influenced corrosion, or MIC. Although they do not produce a unique type of corrosion, they can speed corrosion reactions or influence the mechanisms of corrosion to shift.
The activities of microorganisms have been identified as a contributor to the rapid corrosion of metals and alloys exposed to the following:
- distilled water
- crude oil
- hydrocarbon fuels
- process chemicals
Where MIC is a threat, implementing effective corrosion management systems is challenging since it can occur in conjunction with other corrosion mechanisms or independently. Additionally, before a case of suspected MIC can be identified as the root cause of corrosion, it usually always needs to be confirmed by examining biological, chemical, metallurgical, and operational lines of evidence.
No definitive tests or accepted standardized methodologies exist that can implicate MIC as the probable cause of corrosion rather, it is often determined through a process of deduction of the facts and elimination of other mechanisms. Despite its limitations, serial dilution using liquid culture media has historically been the main method used to identify viable bacteria.