Inhibition and adsorption of oil extract of Balanites aegyptiaca seeds on the corrosion of mild steel in hydrochloric acid environment

The efficiency of oil extract of Balanites aegyptiaca seeds on the inhibition of mild steel corrosion in 1 M HCl has been investigated using gravimetric and electrochemical (Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS)) techniques. Results obtained show that Balanites aegyptiaca (BA) oil extract inhibited the acid corrosion of mild steel. Polarization technique showed that BA oil extract acted as mixed-type inhibitor in 1 M HCl solution. The impedance technique reveals that charge-transfer process controls the corrosion of mild steel. The inhibiting action of BA oil extract was attributed to their adsorption on the mild steel surface and the formation of dense protective layer which increased by increasing their concentration. BA inhibits the corrosion of mild steel by an adsorption mechanism, which follows Temkin adsorption isotherm. Physical adsorption mechanism has been proposed for the inhibitory action of BA oil extract. The protective film formed on the surface was confirmed by scanning electron microscopy (SEM).