Reduction of the chemical erosion of doped graphite due to surface modification during low energy D+ bombardment
The chemical erosion yield of pure graphite during hydrogen bombardment is strongly reduced by dopants like Ti, Si, or B. Preferential sputtering and changes of the surface composition as well as influences of the dopant-carbon bonding on methane formation consequently change the erosion yield. Surface changes may be accentuated at low energy hydrogen ion bombardment and elevated temperatures. The changes of the surface compositions of titanium doped graphites and of pure TiC during bombardment D(+) ions below an ion energy of 1 KeV and temperatures up to 1000 K was investigated. Ti concentrations up to 75 at% at room temperature and stoichiometric TiC concentrations at enhanced temperatures were found. Qualitative investigations of the Auger carbon signal fine structure confirms the phase changes. Due to these changes in material composition the chemical erosion yield is suppressed and the erosion dominated by physical sputtering.
Bibliographic Reference: Article: Journal of Nuclear Materials, Vol. 241-243 (1997) pp. 1156-1159
Record Number: 199711470 / Last updated on: 1997-11-18
Original language: en
Available languages: en