STP1492

    Microstructural Features in Aged Erbium Tritide Films

    Published: Jan 2008


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    Abstract

    Erbium is used as a storage medium for tritium. Microstructural study of helium bubble generation from tritium decay in erbium tritide can provide an unusual example of bubble development with negligible radiation damage. Aged erbium tritide film specimens were found to contain five distinctly different microstructural features. The general structure was of large columnar grains of ErT2. But on a fine scale, precipitates believed to be erbium oxy-tritides and helium bubbles could be identified. The precipitate size was in the range of ∼10 nm and the bubbles were of an unusual planar shape on {111} planes with an invariant thickness of ∼1 nm and a diameter on the order of 10 nm. Also, an outer layer containing no fine precipitate structure and only a few helium bubbles were present on the films. This layer is best described as a denuded zone which probably grew during aging in air. Finally, large embedded Er2O3 particles were found at low density and nonuniformly distributed, but sometimes extending through the thickness of the film. A failure mechanism allowing the helium to escape is suggested by observed cracking between bubbles closer to end of life.

    Keywords:

    tritium decay, helium bubbles, Erbium tritide, microstructure


    Author Information:

    Gelles, D. S.
    Pacific Northwest National Laboratory, Richland, WA

    Brewer, L. N.
    Sandia National Laboratory, Albuquerque, NM

    Kotula, P. G.
    Sandia National Laboratory, Albuquerque, NM

    Cowgill, D. F.
    Sandia National Laboratory, Livermore, CA

    Busick, C. C.
    Sandia National Laboratory, Albuquerque, NM

    Snow, C. S.
    Sandia National Laboratory, Albuquerque, NM


    Paper ID: STP46576S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP46576S


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