Experimental and theoretical study on corrosion inhibition of o-phenanthroline for aluminum in HCl solution

The inhibition effect of o-phenanthroline on the corrosion of aluminum in HCl solution was investigated by weight loss, open circuit potential (OCP), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) methods. The neural and protonated molecular structures of o-phenanthroline were studied by quantum chemical calculation. The results show that o-phenanthroline is a good inhibitor, and the adsorption obeys Langmuir isotherm. From polarization curves, o-phenanthroline acts as a cathodic inhibitor. EIS spectra exhibit a large capacitive loop at high frequencies followed by a large inductive one at low frequencies. The inhibition action is confirmed by SEM images.