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On the mechanism of Ag exudation during internal oxidation / Gunther Schimmel in Acta materialia, Vol. 58 N° 6 (Avril 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 6 (Avril 2010) . - pp. 2091–2102 Titre : On the mechanism of Ag exudation during internal oxidation Type de document : texte imprimé Auteurs : Gunther Schimmel, Auteur ; Julia Sorina-Müller, Auteur ; Bernd Kempf, Auteur Année de publication : 2011 Article en page(s) : pp. 2091–2102 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Oxidation  Internal  stresses  Finite  element  modeling  Phase  nucleation  and  growth  Nodule  formation Résumé : Internal oxidation experiments under different oxidation conditions focusing on the characteristics of noble metal exudation are presented together with finite element method (FEM) simulation calculations of the build-up of internal stresses. In a high-temperature bending test with a fully oxidized Ag–SnO2–In2O3 sample stress states that were comparable with those occurring during internal oxidation were generated, but exudation of Ag was not observed. From further targeted internal oxidation experiments in combination with FEM simulation calculations of internal stress distributions it can be concluded that internal stresses play a minor role in the occurrence of noble metal exudation. It is suggested that exudation occurs due to a gradient in the chemical potential of the noble metal. The potential gradient is a consequence of the concentration gradient of inward diffusing oxygen. The influence of the oxygen-induced driving force on the development of microstructure considering internal and external noble metal layers is discussed. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409008301 [article] On the mechanism of Ag exudation during internal oxidation [texte imprimé] / Gunther Schimmel, Auteur ; Julia Sorina-Müller, Auteur ; Bernd Kempf, Auteur . - 2011 . - pp. 2091–2102. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 6 (Avril 2010) . - pp. 2091–2102 Mots-clés : Oxidation  Internal  stresses  Finite  element  modeling  Phase  nucleation  and  growth  Nodule  formation Résumé : Internal oxidation experiments under different oxidation conditions focusing on the characteristics of noble metal exudation are presented together with finite element method (FEM) simulation calculations of the build-up of internal stresses. In a high-temperature bending test with a fully oxidized Ag–SnO2–In2O3 sample stress states that were comparable with those occurring during internal oxidation were generated, but exudation of Ag was not observed. From further targeted internal oxidation experiments in combination with FEM simulation calculations of internal stress distributions it can be concluded that internal stresses play a minor role in the occurrence of noble metal exudation. It is suggested that exudation occurs due to a gradient in the chemical potential of the noble metal. The potential gradient is a consequence of the concentration gradient of inward diffusing oxygen. The influence of the oxygen-induced driving force on the development of microstructure considering internal and external noble metal layers is discussed. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409008301