Impurity diffusion of cerium and gadolinium in single- and polycrystalline yttria-stabilized zirconia

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 such as phase stability depend on cation diffusion. Therefore, the present work is focused on the diffusion of Ce and Gd in YSZ single crystals and high-density polycrystals. A thin film of Ce or Gd was deposited either by the spin-coating method or by physical vapour deposition on the surface of polished samples. Diffusion experiments were performed between 1173 and 1673 K under air. The Ce or Gd diffusion profiles were determined by secondary ion mass spectrometry. Analysis of the penetration profiles led to the determination of bulk diffusion coefficient (D-b) in single crystals and the effective diffusion coefficient (D-eff), bulk and grain boundary diffusion coefficients (D-gb) were determined in polycrystals. The dependence of diffusion coefficients on temperature is described by means of Arrhenius equations and the diffusivity is compared with results in the literature.