Effect of vegetal tannin on anodic copper dissolution in chloride solutions J. Mabrour a , M. Akssira b , M. Azzi c, * , M. Zertoubi c , N. Saib c , A. Messaoudi a , A. Albizane a , S. Tahiri a,c a Laboratoire de Mat eriaux, Catalyse et Environnement, Facult e des Sciences et Techniques de Mohammedia, B.P 146, Avenue Hassan II, C.P 20650 Yasmina, Mohammedia, Morocco b Laboratoire de Chimie Bio-organique et Analytique, Facult e des Sciences et Techniques de Mohammedia, B.P 146, Avenue Hassan II, C.P 20650 Yasmina, Mohammedia, Morocco c Laboratoire d’Electrochimie et Chimie de l’Environnement, Facult e des Sciences Ain Chock, B.P 5366, C.P 20150 Ma^ arif, Casablanca, Morocco Received 9 May 2002; accepted 19 October 2003 Available online 13 January 2004 Abstract The corrosion inhibition of copper in a 0.1 M NaCl solution in the presence of vegetal tanninusingpotentiodynamictechniqueswasstudied.ThetanninwasextractedfromTakaout galls (Tamarix articulata). The gallic acid has been used as a representative of the tannin species. The tannin are anodic inhibitors. The inhibition efficiency of the tannin evaluated from anodic polarization curves and impedance measurements is about 93.2% for a tannin concentration of 2 g/l. We noted that the presence of tannin changes the mechanism of copper dissolution in a 0.1 M NaCl solution. Microscopic scanning studies of the surface state revealed the formation of corrosion layer products. The impedance investigation allows the explanation of the inhibition process. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Pitting corrosion; Copper; Passive films; Cyclic voltammetry; EIS * Corresponding author. Tel.: +212-22-230-682; fax: +212-22-230-674. E-mail addresses: jamal_mabrour@yahoo.fr (J. Mabrour), azzimed@yahoo.fr (M. Azzi). 0010-938X/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.corsci.2003.10.022 www.elsevier.com/locate/corsci Corrosion Science 46 (2004) 1833–1847