Microbiologically influenced corrosion of X52 pipeline steel in thin layers of solution containing sulfate-reducing bacteria trapped under disbonded coating

Highlights: • The solution thickness affects microbial corrosion of pipelines under coating. • The highest corrosion rate is obtained at the solution thickness of 150 μm. • Both bacterial effect and film formation affect pipeline corrosion in thin solution layers. In this work, microbiologically influenced corrosion (MIC) of an X52 pipeline steel in thin layers of simulated soil solution in the presence of sulfate-reducing bacteria (SRB) under a disbonded polyethylene coating was investigated. The steel MIC depends heavily on the thickness of the solution layer. In the present testing system, there exists a critical solution layer thickness, i.e., 150 μm, where a maximum corrosion rate is reached. Pipeline corrosion in thin layers of solution containing SRB trapped under disbonded coating is resulted from the synergism of MIC and the film formation on the steel surface.