ABSTRACT

The inhibition effect of Ambrosia Maritima, which also named after (Damsissa) extract, towards the corrosion of carbon steel in 1M HCl solution was investigated utilizing potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) methods. The process of adsorption obeyed Langmuir adsorption isotherm. Damsissa extract was found to act as a mixed-type in 1M HCl. The computed adsorption thermodynamic parameters demonstrated that the adsorption was a spontaneous, endothermic process accompanied by an increase in the entropy. The maximum value of the inhibition approached 92.6% within the presence of 300 ppm Damsissa extract utilizing Tafel polarization procedure. The results obtained from the various electrochemical processes were in a great agreement. The inhibition of the extract was assumed to occur through the adsorption of active ingredients on the metal surface. Morphology of the surface was analyzed utilizing scanning electron microscopy (SEM), Fourier transforms infrared (FTIR) and atomic force microscopy (AFM) which confirmed the presence of a protective film of extract molecule on carbon steel 1018 surface.

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ABSTRACT. The inhibition effect of cinnamon plant extract as a green corrosion inhibitor for steel in sulfide polluted salt water was studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM). The results showed that cinnamon plant extract in sulfide polluted salt water is a good corrosion inhibitor with inhibition efficiency reached to 80% at 250 ppm of the plant extract. The adsorption of cinnamon obeys Temkin adsorption isotherm, and acts as a mixed-type of inhibitor but dominantly as a cathodic inhibitor in sulfide polluted salt water.

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