Natural inhibitors are considered because of the absence of harmful environmental effects. Melilotus officinalis(L.) Pallas is a member of the Fabaceae family. It is a biennial herb, native in Europe and Asia. Melilotus officinalis contains coumarinand related compounds such as melilotic acid and o-coumaric acid, flavones, volatile oils, resins and tannins. When dry they have a bitter taste and hay like smell due to coumarin. The constituents include melilotin and other conmarin glycosides, an essential oil and flavonoid pigments. Herein, melilotus officinalis Extract (MOE), was investigated as a green corrosion inhibitor for carbon steel in 0.5 M HCl solution using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). The effect of the temperature on corrosion behavior with addition of different concentrations was studied in the temperature range of 25-45ºC. Polarization curves reveal that the investigated extract is a mixed type inhibitor. The inhibition efficiency was found to increase with increase in the investigated extract concentration and decrease with increase in solution temperature. REFERENCES [1] Abd El -A z iz S. Fouda , Rabab Abo -Shohba , Walaa M. Husien & Esraa S. Ahmed, Global Journal of Researches in Engineering, vol. 15, pp. 8-24, 2015. [2] M. Suhail Anwer, M. Mohtasheem, Iqbal Azhar, S. W. Ahmed and H. Bano, Journal of Basic and Applied Sciences, Vol. 4, pp. 89-94, 2008. [3] E. Martino, I. Ramaiola, M. Urbano F. Bracco, S. Collina, Journal of Chromatography A, pp.147–151, 2006.
