Chromenes as efficient corrosion inhibitor for mild steel in HCl solution.

The Chromene derivatives having heteroatoms as active sites were investigated for scaling downthe corrosion process in mild steel (MS). The effectiveness of the inhibitors was monitored by gravimetric potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Observations suggested that the mechanism of inhibition is mainly due to the adsorption of the inhibitor molecules on the MS surface. Adsorption of both inhibitors follows the Langmuir adsorption isotherm. Tafel curve shows that both inhibitors act as mixed type inhibitor. Morphological studies were done by FESEM and AFM instruments. These images indicated the formation of a protective layer on the MS surface which slows down the process of corrosion. DFT calculation provides the valuable quantum chemical parameters for both inhibitors which are supportive of the results obtained from gravimetric and EIS methods. [ABSTRACT FROM AUTHOR]