Studies on corrosion inhibitory action of Ocimum sanctum (Tulsi) leaves extract in mild steel corrosion induced by Desulfovibrio desulfuricans

Abstract

Studies on the effect of Ocimum sanctum (Tulsi) leaves extract as corrosion inhibitor for mild steel corrosion caused by Desulfovibrio desulfuricans has been carried out. The extract provides 74% inhibition efficiency and is effective up to two weeks. Potentiodynamic polarization studies show the occurrence of pitting corrosion. The electrochemical impedance spectroscopy studies reveal that the nature of the biofilm formed changes continuously. The scanning electron microscopy studies on samples immersed for different durations indicate two layers of different morphologies formed at the end of third and fourth weeks in the uninhibited sample. Energy dispersive x-ray diffraction studies show an increase in sulfide content in uninhibited sample indicating formation of corrosion products.