Enhancing corrosion resistance of mild steel in acid pickling bath: An investigation of new quinazoline derivatives by synthesis, electrochemical analysis EFM, surface analysis, AFM, DFT and molecular dynamics simulation

The current study examines the ability of two novel heterocyclic Quinazoline derivatives, 2-(4-bromophenyl)-3phenyl-2,3-dihydroquinazolin-4(1H)-one (DHQ-4-Br) and 2-(4-hydroxy-3-methoxyphenyl)-3-phenyl-2,3-dihydroquinazolin-4(1H)-one (DHQ-3-OMe-4-OH) to adsorb and protect mild steel against corrosion in a molar solution of hydrochloric acid (HCL). The two materials were identified using nuclear magnetic resonance (NMR) spectroscopy and the experimental investigation employed potentiodynamic polarization (PDP), electrochemical frequency modulation (EFM), and impedance spectroscopy (EIS). The findings demonstrated that DHQ-4-Br and DHQ-3-OMe-4-OH exhibit increasing inhibitory effectiveness as the concentration of the inhibitors increases. Polarization test results suggest that the two inhibitors exhibited mixed-type behavior. The inhibitory efficiency of DHQ-4-Br and DHQ-3-OMe-4-OH was 94.65% and 83.94% respectively. In addition, the Langmuir adsorption model was employed better to understand the adsorption process of the two compounds. The existence of a barrier layer surrounding the SM was demonstrated using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS), and atomic force microscopy (AFM). The results of the density functional theory (DFT) show that the inhibitors that can take electrons have the strongest interactions with the iron surface.