Unveiling the effect of magnetite on the synergistic action of deposits and microorganisms on carbon steel corrosion

The synergistic corrosion effect of microorganisms and deposits on carbon steel corrosion was assessed with magnetite and sand. In the presence of the microbial consortium with magnetite, uniform corrosion rates were 3.5 times higher (0.611 mm/year) than the sum of the corrosion rates promoted by the consortium and deposit separately (0.056 and 0.110 mm/year, respectively). Conversely, with sand, uniform corrosion rates were only 1.5 times higher (0.093 mm/year) than the sum of the corrosion rates promoted by the consortium and deposit separately (0.056 and 0.006 mm/year, respectively). The heightened synergistic effect is attributed to magnetite's semi-conductive nature.