Studying the Inhibition Action of Aqueous Extract of Cinnamomum Verum for Carbon Steel in 1 M HCl Solution

Corrosion inhibitors are a simple and economic method for corrosion control of metals in acidic environments. In this regard, green corrosion inhibitors based on plant extracts have received much attention as a suitable replacement to the synthetic and environmentally unsafe inhibitors. The presence of various active compounds in the aqueous extract of Cinnamomum Verum converted it to a rich source of green inhibitors for steel corrosion control. In this study, the inhibition action of Cinnamomum Verum extract was evaluated by electrochemical and surface analysis methods. The electrochemical impedance spectroscopy (EIS) results demonstrated that after 2.5 h steel immersion in 1 M HCl solution containing 800 ppm inhibitor 88% inhibition efficiency was obtained. In addition, the potentiodynamic polarization results indicated the significant reduction of corrosion current density, anodic and cathodic reactions rates. The images of scanning electron microscopy and atomic force microscopy evidenced the lower steel surface damage, indicating formation of inhibitor film over the steel surface. Furthermore, the inhibitor adsorption obeyed the Langmuir adsorption isotherm.