Inhibition effect of methyl violet on the corrosion of cold rolled steel in 1.0 M HCl solution

The inhibition effect of methyl violet (MV) on the corrosion of cold rolled steel (CRS) in 1.0 M HCl solution at 20–50 °C was studied by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) methods. The results show that MV is an excellent inhibitor even with very low concentration, and the adsorption of MV on CRS surface obeys Langmuir adsorption isotherm. Potentiodynamic polarization curves reveal that MV behaves as a mixed-type inhibitor. EIS spectra exhibit one capacitive loop and confirm the inhibitive ability. The inhibition action of MV is also evidenced by SEM.

Research highlights
► Methyl violet (MV) is found to be a good inhibitor for the corrosion of CRS in 1.0 M HCl.
► MV has an advantage of inhibition efficiency increases with increasing the temperature.
► The corrosion inhibition is satisfactorily discussed by both thermodynamic and kinetic parameters.
► The electrochemical inhibitive mechanism is explained by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) results.