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An electrochemical and surface analytical study of the formation of nanoporous oxides on niobium

Tzvetkov, Bogdan and Bojinov, Martin and Girginov, Assen and Pébère, Nadine An electrochemical and surface analytical study of the formation of nanoporous oxides on niobium. (2007) Electrochimica Acta, 52 (27). 7724-7731. ISSN 0013-4686

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Official URL: http://dx.doi.org/10.1016/j.electacta.2006.12.034


In the present paper, the anodization of Nb in mixed sulphate + fluoride electrolytes resulting in the formation of a nanoporous oxide film has been studied. Chronoamperometry and electrochemical impedance spectroscopy have been employed to characterise in situ the kinetics of the oxidation process. In addition, the evolution of the layer structure and morphology has been followed by ex situ scanning electron microscopy. Particularly, local electrochemical impedance spectroscopy has been used to discern between the mesoscopic 2D and 3D distributions of time constants at the electrode surface. The similarity between local and global impedance spectra during anodic oxidation of Nb demonstrates the presence of an inherent 3D distribution of the high-frequency time constant, which is interpreted as in-depth variation of the steady state conductivity of the passive film. The experimental and calculational results are discussed in relation to the micro- and nanoscopic structure of the formed oxide.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The definitive version is available at http://www.sciencedirect.com The original PDF of the article can be found at Electrochimica Acta website : http://www.sciencedirect.com/science/journal/00134686
HAL Id:hal-00806031
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Other partners > University of Chemical Technology and Metallurgy of Sophia (BULGARIA)
Laboratory name:
Deposited On:25 May 2009 07:13

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