Protective properties of hexacyanoferrate containing polypyrrole films on stainless steel Marcin A. Malik a , Renata Włodarczyk a , Pawel J. Kulesza b , Henryk Bala a, * , Krzysztof Miecznikowski b a Divison of Chemistry, Department of Materials Processing, Technology and Applied Physics, Czestochowa University of Technology, Al. Armii Krajowej 19, PL 42-201 Czestochowa, Poland b Department of Chemistry, University of Warsaw, Pasteura 1, PL 02-093 Warsaw, Poland Available online 20 August 2004 Abstract The protective properties of polypyrrole coatings containing hexacyanoferrate anions are presented. The composite coatings were electrodeposited galvanostatically on stainless steel from the aqueous solutions containing pyrrole monomer and potassium hexacyanoferrate(I together with traces (10 lmol dm 3 ) of free CN ions. The protective properties of the result- ing coatings were investigated in the highly aggressive medium of 0.1 mol dm 3 HCl and 0.4 moldm 3 NaCl. Diagnostic experiments included measurements of open circuit potential wit time of exposure, chronoamperometric (current–time) examination of the steel samples at a selected constant potential of 0.5 V and potentiodynamic measurements. To get insight into the dynamics of the steel dissolution at open circuit potential and at the selected anodic po tial, changes of concentrations of iron and chromium in the test solution as a function of ex sure time were determined using atomic absorption spectrometry. Morphology of the composite film was examined using scanning electron microscopy. 2004 Elsevier Ltd. All rights reserved. Keywords: A.Stainless steel; A. Organic coatings; C. Acid corrosion;C. Polymer coatings; C. Pitting corrosion 0010-938X/$ - see front matter 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.corsci.2004.07.022 * Corresponding author. Tel.: +48 34 325 0704; fax: +48 34 325 0602. E-mail address: hbala@mim.pcz.czest.pl (H. Bala). Corrosion Science 47 (2005) 771–783 www.elsevier.com/locate/corsci