Corrosion Inhibition Effect of Phenolic Extract of Gnetum africana on Copper in 1.0 mol/dm3 Ammonium Hydroxide

Corrosion Inhibition of phenolic extract of Gnetum africana on copper in 1.0 mol/dm3 ammonium hydroxide has been studied using gravimetric (weight-loss) and potentiodynamic polarization techniques. Inhibition efficiency increases with increase in inhibitor concentration, while corrosion rate decreases with increment of Gnetum africana extract concentration. The inhibition was chemisorptions in nature and the absorption the inhibitor on copper surface obeys Langmuir adsorption isotherm. Potentiodynamic polarization suggests that Gnetum africana extract acts as mixed type inhibitor, attending a maximum Inhibition efficiency of 84.21 % as against weight-loss method with 87.83 %.