The Inhibitive Effect of Occimum Gratissmum and Terminlia Chebula Extracts on Corrosion of Iron and Steel

The leaves extract of Occimum gratissimum (OG) and Terminlia chebula (TC) were investigated as alternative environmentally friendly corrosion inhibitor for possible anticorrosion additives to reduce the rate of corrosion of mild steel in 1 M HCl and 0.5 M H2SO4 environments. Gravimetric and potentiodynamic polarization techniques were used in the investigation. The obtained results showed that both OG extract and TC extract reduced the rate of the corrosion reaction considerably. For OG extract, maximum corrosion inhibition efficiency was 94.1% (in 1M HCl) and 90.1% (in 1 M H2SO4) while the TC extract showed maximum efficiencies of 95% and 97.1% in 1 M HCl and 0.5M H2SO4, respectively. Cathodic and anodic polarization curves showed that OG and TC extracts functioned as a mixed-type inhibitor. This study indicates clearly that the studied environmentally friendly biomass extracts has potentials of reducing the corrosion of mild steel in the studied acidic environments.