Imidazole Derivative as a Novel Corrosion Inhibitor for Mild Steel in Mixed Pickling Bath

Mild steel is a well-known and widely used material in various industries. However, its exposure to aggressive environments limits its use because of its tendency to corrode. This work focuses on the inhibition of corrosion of mild steel by two organic compounds based on Imidazole, namely 2-(4-chlorophenyl)-1,4,5-triphenyl-1H-imidazole and 1,2,4,5-tetraphenyl-1H-imidazole, in mixed pickling bath. The experimental investigation was carried out using several techniques including electrochemical impedance spectroscopy and potentiodynamic polarization. The adsorption process of corrosion inhibitors on the mild steel surface follows Langmuir adsorption model. Surface characterization analysis using scanning electron microscopy coupled with energy dispersive X-ray analysis (EDX), X-ray diffraction analysis (XRD) supported the formation of a barrier layer that covers the mild steel surface. Weight loss measurements were also tested using UV-vis spectrometry (UV-vis).