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Influence de l'adsorption de protéine (BSA) sur le comportement électrochimique et la composition de surface d'un alliage Fe-17Cr en solution aqueuse

Abstract : ABSTRACT: The aim of this work was to study the interactions between a model protein, the bovine serum albumin (BSA), and the surface of a ferritic stainless steel, Fe-17Cr, during the initial stages of oxide layer formation in aqueous solution. Different parameters have been tested: potential (corrosion potential Ecor and passive potential), pH (values ranging from 1.3 to 10), and absence/presence of chloride ions in solution. For this purpose, electrochemical methods (polarization curves, electrochemical impedance spectroscopy (EIS)) and X-ray photoelectron spectroscopy (XPS) were coupled. In the absence of chlorides, impedance measurements reveal a corrosion inhibition by the BSA at pH 1.3 and Ecor. XPS analyses show that the BSA layer adsorbed on the stainless steel surface (chemically intact molecules; thickness of about 4 nm) has no influence either on the chemical composition or on the thickness of the oxide and hydroxide layers. Thus, the corrosion inhibition effect evidenced at pH 1.3 and Ecor is due to the protein and not to a change in the chemical composition and/or thickness of the surface layers. In the presence of chlorides (NaCl 0.5M), the protein accelerates the localized corrosion of the passivated Fe-17Cr alloy at pH 5.5; moreover, the pitting potential Ep is lower when passivation and exposure to the BSA are simultaneous. The pitting potential is all the more cathodic as the amount of adsorbed protein is large.
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Contributor : Ecole Chimie Paristech <>
Submitted on : Thursday, April 2, 2009 - 8:00:00 AM
Last modification on : Thursday, April 2, 2009 - 8:00:00 AM
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Luis Lartundo-Rojas. Influence de l'adsorption de protéine (BSA) sur le comportement électrochimique et la composition de surface d'un alliage Fe-17Cr en solution aqueuse. Chemical Sciences. Chimie ParisTech, 2007. English. ⟨pastel-00004963⟩

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