Extract of Allium cepa and Allium sativum as corrosion inhibitors of mild steel in HCl solution

Extracts of Allium cepa and Allium sativum were investigated as corrosion inhibitors of mild steel in hydrochloric acid using gravimetric and gasometric techniques. It was found that the inhibition efficiency increased with the increase of the extract concentration, while the adsorption followed the Langmuir isotherm. The extracts showed similar inhibition efficiency behaviour signifying similarity in the composition of inhibitive compounds. Physical adsorption mechanism has been proposed for the extract used. Kinetic treatment of the results gave a first order type of mechanism. © 2006 SAEST.