Yttrium doping effect on oxygen grain boundary diffusion in α-Al2O3

Tsubasa Nakagawa, Isao Sakaguchi, Naoya Shibata, Katsuyuki Matsunaga, Teruyasu Mizoguchi, Takahisa Yamamoto, Hajime Haneda, Yuichi Ikuhara

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    76 Citations (Scopus)

    Abstract

    The yttrium doping effect on grain boundary diffusion was directly estimated using bicrystal experiments. For this purpose, pristine and yttrium-doped α-Al2O3 bicrystals with the same geometrical configuration were fabricated. The grain boundary oxygen diffusion coefficients were measured by the isotopic tracer profiling technique using secondary ion mass spectrometry. The grain boundary diffusion coefficients of the pristine and yttrium-doped boundary were best described as δ Dgb = 8.4 × 10- 6 exp fenced(- 627 [kJ/mol] / RT) and δ Dgb = 6.5 × 10- 4 exp fenced(- 729 [kJ/mol] / RT), respectively. It was thus found that yttrium doping retards grain boundary diffusivity by approximately 10 times compared to the pristine crystals, while their activation energies were not greatly different. On the other hand, the simultaneously obtained volume diffusion coefficient showed similar values to previously reported results, indicating that extrinsic diffusion occurred in the grain interior. Taking these facts into account, the yttrium effect can be explained by a "site blocking" mechanism or a "swamp out" mechanism, or by both of these.

    Original languageEnglish
    Pages (from-to)6627-6633
    Number of pages7
    JournalActa Materialia
    Volume55
    Issue number19
    DOIs
    Publication statusPublished - 2007 Nov

    Keywords

    • Alumina bicrystals
    • Grain boundary diffusion
    • HREM
    • SIMS

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Ceramics and Composites
    • Polymers and Plastics
    • Metals and Alloys

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