Microbial corrosion of protective coatings

Research studies have shown that protective coatings of diverse chemical composition represent a powerful factor stimulating the bacterial activity of corrosion inducers. On the film and mastic coatings investigated in the present paper, bacterial communities are formed, which consist of bacteria of various ecological trophic groups. Bacteria in a biofilm are characterised by high metabolic activity and the ability to destroy traditional coatings. As a result of microbial destruction, the physical mechanical and chemical properties of a material undergo significant changes. The characteristics of strength, elasticity and adhesion deteriorate, thus degrading the main function of the coatings, i.e. protection of metal against corrosion. An efficient method of protection against biodeterioration is the addition of corrosion inhibitors with biocide action into their composition. It was established that the population of bacteria on oil bitumen coatings modified by antimicrobial bonds is 1-4 orders lower than on materials with no such additives. Protection of underground structures against corrosion should be performed comprehensively with consideration of the biocorrosivity of soils and bioresistance of coatings.