A correlated theoretical and electrochemical investigation of the corrosion inhibition performance of phenolic Schiff bases on mild steel in HCl solution (Part B)

[Display omitted] •Phenolic Schiff bases exhibits higher inhibition efficiencies in 1 M HCl.•Electrochemical test data indicate the order of inhibition performance: PSB4 > PSB3.•A potentiodynamic analysis indicated that PSBs were likely mixed-type inhibitors.•Surface characteristics analysis strongly supported steel surface inhibition film.•Theoretical modeling offers a detailed insights into PSBs inhibition performance. For many industries, corrosion is a serious issue. For this reason, corrosion inhibitors are constantly being researched and developed to be utilized in a broad range of industrial applications. Thus, two phenolic Schiff bases named (E)-4-(1-((4-hydroxy-6-methylpyrimidin-2-yl)imino)ethyl)benzene-1,3-diol (PSB3) and (E)-4-((pyrimidin-2-ylimino)methyl)phenol (PSB4) were tested for their ability to prevent corrosion in mild steel (MS). Experiments involving gravimetry and electrochemistry are used. Furthermore, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) surface analysis verified the inhibitors' successful deposition. Inhibitors are most effective in preventing corrosion damage with lowering temperature and rising of inhibitors amount., nearing 75.6 % (PSB3) and 97.3 % (PSB4) at 303 K and 1 × 10-3 M, respectively. Hence, the inhibitors PSB3 and PSB4 are likely of the mixed-form, with their Ecorr values changing by 13.2 and 14.7 mV, respectively, with respect to the blank solution. In addition, it was found that the free energy of adsorption for these inhibitors on the MS face followed the Langmuir adsorption isotherm with values of −41.06 and −39.90 KJ/mol. The SEM and EDS studies also demonstrated surface adsorption. The outcomes of the experiments corroborate the conclusions of the computer modeling.