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Publications in Scientific Journals:

C. Tomastik, W.S.M. Werner, H. Störi:
"Oxidation of beryllium - a scanning Auger investigation";
Nuclear Fusion, 45 (2005), 1061 - 1065.



English abstract:
Beryllium is considered to be a candidate material for the first wall of
nuclear fusion plasma experiments, e.g. ITER.
In this application, the interaction of beryllium with oxygen is
important for two reasons. One aspect is the reaction
of hot beryllium with air in case of a catastrophic leak, the other is
the action of beryllium as a getter, binding oxygen
impurities and thus helping to keep the level of contamination in the
plasma low. We therefore investigated the
interaction of beryllium with air at elevated temperatures up to 600C
on a microscopic level, using a high resolution
Auger electron microscope. At 390C, a thin protective oxide film is
formed, while at 500C oxidation starts to enter
into the grain boundaries, leading to the loosening of small particles
of beryllium already at 600C. The expected
diffusion of oxygen from the surface into the bulk has not been observed
up to 390C, the highest temperature to
be safely applied inside the Auger microscope. Exposure to hydrogen
atmosphere showed no change up to 600C,
exposure to hydrogen plasma resulted in an equilibrium thickness of the
oxide layer, which is most likely due to
impurities in the plasma. Thus, an operation of beryllium liners as a
non-evaporable getter is not to be expected in
this temperature range. Getter activity linked to the transport of
beryllium from the liner to some deposition areas is,
however, possible.


Online library catalogue of the TU Vienna:
http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC05938021


Created from the Publication Database of the Vienna University of Technology.