Role of ureolytic bacteria on corrosion behavior of fretted grade 880 mild steel rail

Corrosion due to toilet droppings has a pronounced effect on rails. In the present study, corrosion behavior of Mild Steel (Grade 880) was evaluated by bacterial spray chamber in presence of bacteria, and the impact of air bacteria on fretted steel was investigated. The production of ammonia and pH of medium in presence of microbes were monitored at regular intervals. The pH was observed to rise to a value of 9.6, with increase in estimated ammonia content to 6000 ppm. Conversion of FeOOH in bare steel to Fe2O3 and FeO as a result of corrosive attack by bacterial species revealed from XRD data. Bacterial contribution was significant in augmenting the rate of corrosion in fretted mild steel samples. SEM reveals the occurrence of pitting on fretted steel under bacterial spray chamber environment. The present study concludes by inferring that the presence of ureolytic bacteria enhances corrosion in fretted Mild steel (Grade 880).