Corrosion Inhibition and Adsorption Behavior of Gentian Violet on AISI 4130 Alloy Steel in HCl Solution

The inhibition ability of hexamethyl pararosaniline chloride (gentian violet) on the corrosion resistance of AISI 4130 steel in 1 M HCl solution was studied by potentiodynamic polarization (Tafel), electrochemical impedance spectroscopy and scanning electron microscopy (SEM). Polarization studies indicated that the inhibition efficiency increases with the increase in inhibitor concentration and inhibitor retards both the cathodic and anodic reactions, so are classified as mixed type inhibitors. The effect of temperature on the corrosion behavior of steel in HCl with the addition of the inhibitor was studied in the temperature range from 25 to 65 °C. The experimentally obtained adsorption isotherms follow the Langmuir equation. Activation parameters and thermodynamic adsorption parameters of the corrosion process such as E _a , ΔH, ΔS, K _ads and ΔG _ads were calculated at different temperatures and using the adsorption isotherm. The morphology of steel surface after its exposure to HCl solution in the absence and presence of inhibitor was examined by SEM images.