Electrochemical, thermodynamic, and theoretical study of the corrosion inhibition properties of triglycidyloxy tripropylamine triazine on E24 steel in 1 M HCl

The goal of this study is to investigate the corrosion inhibition characteristics of triglycidyloxy tripropylamine triazine (TGTPAT) on E24 steel in a 1 M hydrochloric acid medium. We used electrochemical methods (polarization curves and electrochemical impedance spectroscopy) to carry out this investigation. The polarization curves demonstrate that the TGTPAT mixed-type inhibitor has an inhibition effectiveness (IE%) of 92.11% at a dose of 10–3 M. The electrochemical impedance diagrams for all tested TGTPAT concentrations show that the inhibition occurs via a charge transfer mechanism on a heterogeneous surface; the IE% was 90.19 at 10–3 M, which was consistent with the results of dynamic polarization. The inhibitor adsorption on the metal surface was of the Langmuir type, with a negative ΔGads value indicating that the adsorbed layer on the metal surface is stable. Furthermore, the ΔGads approach value of 40 kJ/mol relates to charge transfer between TGTPAT inhibitor molecules and the metal surface E24 (chemisorption), resulting in the formation of covalent or coordination bonds. SEM/EDX analysis: after 20 hours of immersion in the corrosive solution with an inhibitor, it was confirmed that the surface of the metal was protected and homogeneous. Peaks of iron, oxygen, and carbon are also visible, indicating the presence of the inhibitor’s components on the surface. An investigation into the effect of increasing temperature revealed that as temperature rises, so does the corrosion current density, resulting in a decrease in inhibitor efficiency. Quantum chemical calculations of TGTPAT corrosion inhibitors were performed to investigate the effect of molecular structure on inhibition efficiency.