Electrochemical and Quantum Chemical Studies on Synthesized Phenylazopyrimidone Dyes as Corrosion Inhibitors for Mild Steel in a 15% HCl Solution

摘要

The inhibition performance of synthesized phenylazopyrimidone dyes, namely, 3-(p-nitrophenylazo)- 4-amino-1H- benzo[4,5]imidazo[1,2-a]pyrimidin-2-one (NABIP) and 3-(p-methoxyphenylazo)-4- amino-1H- benzo[4,5]imidazo[1,2-a]pyrimidin-2-one (MABIP) were investigated as corrosioninhibitors for mild steel in a 15% HCl solution using potentiodynamic polarization andelectrochemical impedance spectroscopy (EIS) measurements. The inhibition efficiency of bothinhibitors increased with an increase in the concentration of inhibitor. The inhibitors NABIP andMABIP at a concentration of 200 ppm at 303 K show corrosion inhibition efficiencies of 93.1 and97.9%, respectively. Polarization studies showed that both inhibitors studied were of a mixed type innature. The adsorption of inhibitors on the mild steel surface obeys the Langmuir adsorption isotherm.Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and atomic forcemicroscopy (AFM) were performed for the surface study of the uninhibited and inhibited mild steelsamples. Density functional theory (DFT) was employed for theoretical calculations.