The impact of additional nitrates in mild steel corrosion in a seawater/sediment system

•A significant increase in weight loss of the coupons with nitrate treatment.•An increase in sulphate reduction bacteria in coupons with nitrate treatment.•Biofilm/corrosion products were more evident in coupons with nitrate treatment.•Increases in organic, decreases in Fe contents in coupons during incubation.

This paper investigates the impact of additional nitrate sources on mild steel coupon corrosion in a seawater/sediment system. The results show that addition of 5 mM of nitrate sources significantly increased the weight loss of coupons after 20 weeks. SEM results indicate increase in microbial populations and corrosive products in the non-autoclaved and the nitrate-treated environments. EDX analyses revealed an increase in contents of carbon, calcium, magnesium, phosphorus and sodium with the exception of iron with an increase in incubation time.