Impurity diffusion of cerium and gadolinium in single- and polycrystalline yttria-stabilized zirconia
Résumé
Yttria-stabilized zirconia (YSZ) ceramic is considered as an attractive material for solid oxide fuel cells or for nuclear applications such as inert matrix for the destruction of excess plutonium and host material for nuclear waste storage. Long term properties as phase stability depend on cation diffusion. Therefore, the present work is focused on the diffusion study of Ce and Gd in YSZ single crystals and high density polycrystals. A thin film of Ce or Gd was deposited either by spin-coating method or by physical vapour deposition on the surface of polished samples. The diffusion experiments were performed from 1173 to 1673 K under air. The Ce or Gd diffusion profiles were determined by secondary ion mass spectrometry. The analysis of the penetration profiles led to the determination of bulk diffusion (Db) in single crystals and effective (Deff), bulk and grain boundary diffusion coefficients (Dgb) were determined in polycrystals. The dependence of diffusion coefficients on temperature is described by means of Arrhenius equations and the diffusivity is compared with literature.
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