Effect of Cysteine as Environmentally Friendly Inhibitor on AA6061-T6 Corrosion in 0.5 M HCl: Electrochemical and Surface Studies

The inhibitive action of cysteine was investigated against the corrosion of aluminium alloy 6061-T6 (AA6061-T6) in a 0.5 M hydrochloric acidic medium in the temperatures range of 303-323 K using potentiodynamic polarization as well as electrochemical impedance spectroscopy methods. The electrochemical results of the former were validated by the latter. Cysteine showed mixed inhibitor behavior and exhibited good inhibition performance. The thermodynamic properties indicated mixed adsorption behavior of cysteine, which satisfied the Langmuir adsorption isotherm. The surface morphological investigation of both corroded and inhibited specimens was performed using a scanning electron microscopy and atomic force microscope, which revealed the adsorption of cysteine onto the alloy surface.