Reinforcement of low-carbon steel against corrosion in acidic condition by some Schiff bases: Experimental and theoretical studies

Interface of low-carbon steel with acid solution in the presence of Schiff bases, 2-((2-hydroxybenzylidene)amino)benzoic acid (1), 2-(((1H-pyrrol-2-yl)methylene)amino)phenol (2), and Bis-((1H-indol-3-yl)methylene)cyclohexane-1,2-diamine (3) has been studied using different strategies includes; traditional weight loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), adsorption studies, and quantum chemical calculations. Inhibition efficiency (IE) of all the three Schiff bases on corrosion of low-carbon steel in 1 M hydrochloric acid increases with increasing the concentration of Schiff bases. The inhibition properties of these Schiff bases are discussed by means of blocking the steel surface through adsorption. Scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and X-ray diffraction (XRD) studies of the steel surfaces confirmed the presence of adsorbed film. Theoretical calculations using density functional theory (DFT) are also performed to verify the experimental results.