Synthesis and characterization of an effective green corrosion inhibitive hybrid pigment based on zinc acetate-Cichorium intybus L leaves extract (ZnA-CIL.L): Electrochemical investigations on the synergistic corrosion inhibition of mild steel in aqueous

In this study a new generation of corrosion inhibitive pigment based on zinc acetate-Cichorium intybus L leaf extract (ZnA-CIL.L) has been synthesized and characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), UV-visible analysis and thermal gravimetric analysis (TGA). Then, the corrosion inhibition performance of the ZnA-CIL.L hybrid pigment was studied by open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS) and polarization studies in 3.5 wt% NaCl solution on mild steel substrate. The surface morphology and chemistry of the steel panels dipped in the solutions without and with ZnA-CIL.L pigment extract was studied by SEM/EDS and FT-IR analyses. Results obtained from XPS, SEM/EDS, FT-IR, TGA and UV-visible analyses confirmed the successful complex formation of ZnA-CIL.L. The CIL.L extract consists of many corrosion inhibitive molecules i.e Flavone, Caffeic acid and Chicoric acid, that are full of electron-rich groups with high capability of sharing their lone pairs with Zn2+ cations, that have empty 3d orbital. Results obtained from OCP, EIS and polarization tests confirmed that the ZnA-CIL.L hybrid pigment, in its extract form in saline solution, could remarkably retard the steel sample from corrosion. Due to the synergistic effect between CIL.L and Zn2+ cations both the anodic and cathodic reactions were noticeably suppressed and inhibited in the presence of ZnA-CIL.L extract. The CIL.L molecules adsorption on the anodic sites occurred through chelation with zinc/iron cations, and the zinc cations deposited on the cathodic sites in the form of zinc hydroxide, providing proper inhibition performance for this hybrid green corrosion inhibitive pigment.