Development of pitting corrosion for mild steel exposed to particulate media and natural and nutrient-dosed seawaters

Corrosion of mild steel in contact with both seawater and particulate media has important practical implications. It is considered herein for coupon exposures up to 2 years in 0.05 and 0.425 mm (nom.) granular media in natural Pacific Ocean seawater and in seawater dosed with calcium nitrate ostensibly to stimulate microbiological corrosion. The observed pit depths were consistent with an empirical bi-modal corrosion prediction model and overall lowest for smaller particle sizes and greatest without particles. Contrary to expectations, nutrient dosing tended to reduce pit depths. The observations are discussed in the light of earlier observations and for relevance to practical implications.