Pyrazole-based schiff bases as high-performance corrosion inhibitors for mild steel: Experimental and theoretical insights

Background: The increasing demand for effective corrosion inhibitors for mild steel (MS) in acidic environments has led to the exploration of pyrazole-based Schiff bases (PSBs). This study evaluates the corrosion inhibition performance of two PSB derivatives in 1 M HCl at temperatures ranging from 298 to 318 K. Methods: Corrosion inhibition efficiency was assessed using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and weight loss measurements. Surface morphology was analyzed through atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), and energy-dispersive spectroscopy (EDS). Contact angle (CA) measurements examined surface hydrophobicity, while activation energy and thermodynamic parameters provided insights into inhibition mechanisms. Density functional theory (DFT) and molecular dynamics (MD) simulations were employed to investigate electronic properties and adsorption behavior. Significant Findings: The Schiff base derivatives, CMPNA and CMPAP, exhibited inhibition efficiencies of 95.27 % and 93.59 %, respectively, at 300 ppm and 298 K, as determined by EIS. Adsorption followed the Langmuir isotherm model, forming a protective layer via strong physical and chemical interactions. CA measurements confirmed enhanced hydrophobicity. Theoretical calculations supported experimental results, highlighting the potential of PSBs as efficient and eco-friendly corrosion inhibitors for MS protection in acidic media.