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Stability of the passive state of Zr–Nb crystalline alloys / F. Rosalbino in Materials and corrosion, Vol. 63 N° 7 (Juillet 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 7 (Juillet 2012) . - pp. 580–585 Titre : Stability of the passive state of Zr–Nb crystalline alloys Type de document : texte imprimé Auteurs : F. Rosalbino, Auteur ; D. Macciò, Auteur ; A. Saccone, Auteur Année de publication : 2012 Article en page(s) : pp. 580–585 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Electrochemical  impedance  spectroscopy  (EIS);  passive  state;  pitting  corrosion;  potentiodynamic  polarization  curves;  Zr–Nb  alloys Résumé : Stability of the passive state was assessed for pure Zr and four Zr–Nb alloys (2.5, 5.0, 10.0, 25.0 at.% Nb) after 24 h exposure to naturally aerated 3.5% NaCl solution (pH = 6). Open circuit potential values indicated that all the Zr–Nb alloys studied and the pure Zr undergo spontaneous passivation due to spontaneously formed oxide film passivating the metallic surface. It also indicated that the addition of increasing Nb contents to pure Zr seems to improve the protection characteristics of its spontaneous oxides. Potentiodynamic polarization curves showed an increase of the breakdown potential and the extent of the passive range following an increased niobium amount in the alloy. This leads to the conclusion that a progressive increase of niobium content positively affects the localized corrosion behaviour of the Zr–Nb alloys by enhancing the electrochemical stability of the passive film. Electrochemical impedance spectroscopy (EIS) studies showed high impedance values for all the samples, and its increase on increased niobium content in the alloy indicated an improvement in the corrosion resistance of the spontaneous oxide film. The fit obtained suggests a single passive film present on the metal surface, with resistance improving with the increase of niobium amount in the alloy. All these electrochemical results show the beneficial effect of increasing niobium contents on the passive state stability of the Zr–Nb alloys. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201006012/abstract [article] Stability of the passive state of Zr–Nb crystalline alloys [texte imprimé] / F. Rosalbino, Auteur ; D. Macciò, Auteur ; A. Saccone, Auteur . - 2012 . - pp. 580–585. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 7 (Juillet 2012) . - pp. 580–585 Mots-clés : Electrochemical  impedance  spectroscopy  (EIS);  passive  state;  pitting  corrosion;  potentiodynamic  polarization  curves;  Zr–Nb  alloys Résumé : Stability of the passive state was assessed for pure Zr and four Zr–Nb alloys (2.5, 5.0, 10.0, 25.0 at.% Nb) after 24 h exposure to naturally aerated 3.5% NaCl solution (pH = 6). Open circuit potential values indicated that all the Zr–Nb alloys studied and the pure Zr undergo spontaneous passivation due to spontaneously formed oxide film passivating the metallic surface. It also indicated that the addition of increasing Nb contents to pure Zr seems to improve the protection characteristics of its spontaneous oxides. Potentiodynamic polarization curves showed an increase of the breakdown potential and the extent of the passive range following an increased niobium amount in the alloy. This leads to the conclusion that a progressive increase of niobium content positively affects the localized corrosion behaviour of the Zr–Nb alloys by enhancing the electrochemical stability of the passive film. Electrochemical impedance spectroscopy (EIS) studies showed high impedance values for all the samples, and its increase on increased niobium content in the alloy indicated an improvement in the corrosion resistance of the spontaneous oxide film. The fit obtained suggests a single passive film present on the metal surface, with resistance improving with the increase of niobium amount in the alloy. All these electrochemical results show the beneficial effect of increasing niobium contents on the passive state stability of the Zr–Nb alloys. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201006012/abstract