Fungal Corrosion of Mild Steel and the Application of Aframomum melegueta Biomass Extract as Natural Source of Inhibition

Abstract

Studies on fungal influenced corrosion of mild steel (MS) in the presence of Acremonium kiliense and Aspergillius fumigatus and their inhibition by seed extracts of Aframomum melegueta were carried out using gravimetric and potentiodynamic polarization techniques. The results revealed that the metal reacted differently to the impact of fungi. The influence depends on the capacity of fungi to develop on the metal surface and produce metabolites stimulating changes in polarization resistance and destruct the surfaces. A. fumigatus proved to be the most active destructor of mild steel with cumulative corrosion rate (∑CR) of 7.85±0.91mpy and corrosion current density (I_corr) of 279.4μA/cm². The gravimetric analysis further revealed that the corrosion rate and weight loss of the metals increased with time. The anticorrosion studies at 25mg/mL concentration showed that the inhibitor exhibited a mixed-type inhibition, inhibiting both the cathodic and anodic sites. A. melegueta was more effective against A. kiliense (85%IE).

Keywords: Corrosion, Fungi, Inhibition, Plant extract, Polarization, Mild steel