Author(s): Lgaz H, ELaoufir Y
The effects of (E)-3-(4-methoxystyryl)quinoxalin-2(1H)-one (Q1) and its synergistic effect with KI on the corrosion of carbon steel in 1.0 M HCl solution were studied using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. The inhibition efficiency increases with the concentration of the inhibitor and increased further with the presence of 1.0 mM KI. The synergistic effect of 1.0 mM KI at different concentrations of Q1 was determined by calculating the synergism parameters. EIS plot indicates that the addition of inhibitor increases the charge-transfer resistance (Rct) and decreases the double-layer capacitance (Cdl) of the corrosion process. The adsorption of Q1 and KI on the metal surface in 1.0 M HCl solution obeys the Langmuir adsorption isotherm.