Corrosion of bare and silane-coated mild steel in chloride medium with and without sulphate reducing bacteria

Influence of Bis[triethoxysilyl]ethane (BTSE) silane coating on the corrosion resistance of a mild steel in an aerobic chloride medium and an anaerobic microbial medium containing sulphate reducing bacteria (SRB) was analysed using a comprehensive electrochemical and chemical analyses. The Silane coating acted as a physical barrier and significantly improved the corrosion resistance of mild steel in an aerobic chloride medium. However, the improvement was limited in the anaerobic microbial medium. Surface morphology examination and chemical analysis using Fourier transformed infrared spectroscopy confirm the formation of a dense biofilm on BTSE-coated surface after pre-exposure to biotic media, which can be attributed to the absence of any antimicrobial functional group in this silane. This study is first of its kind to indicate the limitations of established coating systems in retarding microbial corrosion and emphasizes the importance of the modification of current coating systems with anti-microbial functional groups to impede the formation of biofilms and effectively hinder microbial corrosion.