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MM: Metall- und Materialphysik
MM 38: Nanostructured Materials II
MM 38.6: Vortrag
Donnerstag, 30. März 2006, 17:45–18:00, IFW D
Diffusion of oxygen in nanocrystalline ZrO2·Y2O3 — •Harald Drings, Anthony Madubuonu, Gregor Knöner, and Hans-Eckhardt Schaefer — Universität Stuttgart, Institut für Theoretische und Angewandte Physik, 70550 Stuttgart, Germany
Zirconia-based materials are known to have oxygen transport properties which give rise to many applications, such as gas sensors or solid electrolytes for fuel cells. It has been recently shown that the oxygen diffusivity in the grain boundaries of nanocrystalline ZrO2·Y2O3 is strongly enhanced [1] compared to the volume diffusion. Due to the large amount of interfaces in nanocrystalline materials, this should significantly enhance the oxygen diffusion current. This could lower the operating temperature e.g. of solid oxide fuel cells (SOFC) and reduce material deterioration. The samples were prepared by gas phase synthesis of metallic nanoparticles that were oxidized, compacted and sintered to a fully dense oxide specimen. Here, we report on reducing the grain size in n-ZrO2·Y2O3 by Al doping in order to increase the diffusion current.
[1] G. Knöner et. al. , PNAS 100, 3870 (2003)