Influence of N², N⁶-bis((3,5-dimethyl-1h-pyrazol-1-yl)methyl) pyridine-2,6-diamine on C35E steel corrosion in 1 M HCl medium: Experimental and theoretical studies

Abstract

The inhibition effect of N², N⁶-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)pyridine-2,6-diamine (MH-PA) on the corrosion of C35E steel in 1 M HCl solution was investigated employing potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier-transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), contact angle, X-ray photoelectron spectroscopy (XPS) methods, UV-visible spectroscopy, and theoretical calculation methods. The inhibition efficiency increased with increasing MH-PA concentration and decreased with increasing temperature, attaining 98% inhibition efficiency at 10⁻³M under 303K. PDP studies indicated that MH-PA is a mixed-type corrosion inhibitor and its adsorption mode conforms to Langmuir isotherm. UV-visible and FTIR spectroscopy support MH-PA adsorption over the C35E steel surface. The surface analysis through SEM, EDS, AFM, and contact angle corroborates the formation of the protective layer of MH-PA molecules on the C35E steel surface. In addition, XPS analysis revealed the formation of an N-Fe bond. Thermodynamic properties revealed that MH-PA has both physical and chemical adsorption behavior. Molecular dynamics simulations manifest that MH-PA molecules adsorb parallel to the Fe (110) surface.

GRAPHICAL ABSTRACT

Keywords:

• Pyrazol-pyridine derivative
• C35E steel corrosion
• adsorption isotherms
• XPS
• theoretical calculations

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This project was supported by Researchers Supporting Project number (RSP2024R78), King Saud University, Riyadh, Saudi Arabia.