Highly Efficient Corrosion Inhibitor for Pure Iron and Aluminum Metals in Aggressive Acidic Medium: Experimental and Computational Study

Highlights: What are the main findings? MHBTZ exhibits excellent corrosion inhibition performance for pure iron and aluminum in aggressive acidic media. EIS results reveal very high inhibition efficiencies of 98.94% for Fe and 99.16% for Al at 2500 ppm. PDP measurements confirm that MHBTZ acts as a mixed-type inhibitor, suppressing both anodic metal dissolution and cathodic hydrogen evolution. Experimental findings are strongly supported by DFT and MD simulations, indicating robust interactions between the inhibitor and metal. 3D optical profilometry demonstrates the formation of a compact and protective film on Fe and Al surfaces in the presence of MHBTZ. What are the implications of the main findings? MHBTZ can be considered a highly effective organic inhibitor for protecting Fe- and Al-based materials in acidic industrial environments. The combined experimental–computational approach provides reliable mechanistic insight into corrosion inhibition behavior. The high efficiency at relatively low concentration highlights the potential of MHBTZ for cost-effective and practical corrosion control applications. The influence of 5-Methyl-1H-benzotriazole (MHBTZ) on the corrosion of pure iron (Fe) and aluminum (Al) in 1 M HCl was investigated in this study. The experimental and theoretical aspects of MHBTZ adsorption onto pure iron (Fe) and aluminum metal (Al) surfaces, as well as the stability of adsorbed layers based on the metal type, were also studied. Different electrochemical measurements were performed to explore the corrosion rates and inhibition efficiencies on the Fe and Al surfaces at 298 K. Optical profilometry was used to obtain the 3D surface topography of Fe and Al metals after immersion with and without the MHBTZ molecule. The results showed that MHBTZ exhibited excellent inhibition properties for both metals. Electrochemical impedance spectroscopy (EIS) achieved inhibition efficiencies of 98.1% and 98.5% for Fe and Al, respectively, at a concentration of 2500 ppm. Potentiodynamic polarization (PDP) indicated that MHBTZ acted as a mixed-type inhibitor. Density functional theory (DFT) analysis and molecular dynamics (MD) simulations were used to explore the relationship between the molecular structure of MHBTZ and its inhibition efficiency at the atomic level.