Promising corrosion resistance of mild steel, copper, and aluminum in hydrochloric acid solution using an environmentally friendly corrosion inhibitor

Abstract

The current study assessed the anticorrosion features of 6-chloro-2-(4-chlorophenyl)imidazo[1,2-a]pyridine-3-carbaldehyde (AIM) in mitigating corrosion of three different metals: Mild Steel (MS), Copper (Cu) and Aluminum (Al) in 1 M HCl solution. The adsorption process of AIM on these metal surfaces, as well as the stability of the adsorbed layer and its relationship with the type of metal were comprehensively investigated. To achieve our objectives, several techniques were used, such as: Potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), SEM surface characterization, and theoretical approaches. Electrochemical impedance spectroscopy investigations revealed high corrosion inhibition rates, reaching 99.01 %, 96.06 %, and 84.8 % for Cu, MS and Al, respectively, at a concentration of 10−3 M of AIM. Potentiodynamic polarisation validated the mixed type nature of inhibitor, a satisfactory correlation was observed between the results obtained by EIS and those obtained by the PDP technique. The adsorption study showed that the process was mainly controlled by chemical adsorption, and metal dissolution was an endothermic process. Additionally, surface analysis by scanning electron microscopy (SEM) confirmed the formation of a protective AIM film on the electrode surface, resulting in a significant reduction in metal dissolution in the presence of aggressive ions. The exploration of the relationship between molecular structure, inhibitory properties of AIM and the studied metals, was conducted through quantum chemical analysis and dynamic molecular simulation.