Inhibitor action of Ocimum Basilicum and Melia Azedarach extracts on the corrosion of mild steel in acidic medium

Melia Azedarach (TAE) and Ocimum Basilicum (FES) extracts were investigated as eco-friendly corrosion inhibitors of mild steel in 1.0 M HCl using potentiodynamic polarization, linear polarization resistance, electrochemical impedance spectroscopy (EIS), scanning electron microscopy and atomic force microscopy techniques. The experimental results show that TEA and FES are good corrosion inhibitor and the inhibition efficiencyis increased with TEA and FES extract concentrations. The results of AC impedance have shown that polarization resistance increased and constant phase element decrased with increasing TAE and FES concentrations. Polarization curves indicated that TAE and FES are mixed inhibitors. Scanning electron and atomic force microscopy studies confirmed the formation of a protective film on the mild steel surface. The inhibitors adsorbed on the iron surface was found to be in a good agreement with the Langmuir adsorption isotherm and the value of adsorption free energy of (G°ads) were also calculated.