Inhibitory effect of Eucalyptus and Lippia Alba essential oils on the corrosion of mild steel in hydrochloric acid

The inhibitory effect of two essential oils, Eucalyptus and Lippia Alba, were estimated on the corrosion of mild steel in 0.5 M hydrochloric acid (HCl) using weight loss, Electrochemical Impedance Spectroscopy (EIS) and Tafel polarization curves. Inhibition was found to increase with increasing concentration of the essential oils. The effect of temperature on the corrosion behavior of mild steel in 0.5M HCl with addition of essential oils was also studied. Values of inhibition efficiency calculated from weight loss, Tafel polarization curves, and EIS are in good agreement. Polarization curves showed that Eucalyptus and Lippia Alba essential oils behave as mixed type inhibitors in hydrochloric acid. The results obtained showed that the Eucalyptus and Lippia Alba essentials oils could serve as an effective inhibitor of the corrosion of mild steel in Hydrochloric acid solution. The superficial analysis of mild steel was performed using optical microscopy and infraredspectroscopy