Inhibition of Corrosion of Aluminum Alloy AA8011 in Alkaline Medium Using Palisota hirsute Extract

Gravimetric technique was used to study the inhibition of aluminium alloy AA8011 in an alkaline medium using an eco-friendly inhibitor, Palisota hirsute. The study revealed that the extract reduced the corrosion rate of aluminium AA8011 from 0.407 mm/yr to as low as 0.106 mm/yr in 0.25 M KOH after being exposed for five hours. The inhibition efficiency was found to increase as the concentration of the plant extract in the medium increased. The adsorption studies, computed from the experimental data revealed Langmuir isotherm as the best model for the isotherm (r2=0.999) on the mild steel surface. Gibb’s free energy of adsorption was also calculated and gotten to be 15.61 kJmol-1, suggesting that inhibitor molecules have been spontaneously adsorbed onto the aluminum surface through physical adsorption mechanism.