Inhibition of Mild Steel Corrosion in Hydrochloric and Sulfuric Acid Media Using a Thiosemicarbazone Derivative

Abstract

The inhibitive effect of 4-(N,N-dimethylamino)benzaldehyde thiosemicarbazone (DMABT) on the corrosion of mild steel (MS) in 1 N HCl and 1 N H2SO4 solutions was investigated by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopic measurements. It is inferred on the basis of the obtained results that DMABT is a mixed-type inhibitor, predominantly retarding cathodic reaction in both acidic media through adsorption on a MS surface. Adsorption obeys Langmuir's adsorption isotherm in both acidic media. The observations regarding energy-dispersive X-ray, scanning electron microscopy, and atomic force microscopy confirm the existence of a protective film of the inhibitor on a MS surface. The molecular adsorption of DMABT was ascertained by density functional theory data.