Gravimetric, Electrochemical, and Surface Morphological Studies of Ammodaucus Lecotrichus Essential Oil as Corrosion Inhibitor for Copper Surface in Hydrochloric Acid Medium

The aim of this work is the study of the inhibition corrosion of copper in hydrochloric acid solution 2M using essential oil of ammodaucus leucotrichus Coss. & Dur. noted (AEO). Its protective ability is evaluated by weight loss measurements, electrochemical impedance spectroscopy (EIS) and polarization curves, at different concentrations of the oil (0-3000 ppm) and by varying the temperature of the solution (298-328K). The polarization curves highlight the cathodic character of this eco-friendly inhibitor. However, the corrosion rate was reduced when the concentration of AEO is increased and achieves about 70% after 6h immersion in corrosive media containing 3000 ppm of AEO. This important protection ability is relied to the formation of a protective film over the metal, which its adsorption is governed by the Langmuir isotherm model. The negative values of the free standard adsorption energy ΔGads confirm the spontaneity of the reaction. Interestingly, scanning electron microscopy (SEM) analysis underlines a remarkable enhancement on the surface of copper exposed to the corrosive media, in presence of AEO and hence, its efficiency as an ecofriendly inhibitor for copper surface.