Y. Hirooka et al., EFFECT OF IMPURITIES ON THE EROSION BEHAVIOR OF BERYLLIUM UNDER STEADY-STATE DEUTERIUM PLASMA BOMBARDMENT, Journal of nuclear materials, 228(1), 1996, pp. 148-153
Citations number
10
Categorie Soggetti
Nuclear Sciences & Tecnology","Mining & Mineral Processing","Material Science
As a candidate plasma-facing material for ITER, beryllium has been eva
luated with respect to deuterium plasma erosion characteristics using
the PISCES-B Mod facility at ion fluxes around 5 x 10(21) ions s(-1) m
(-2) in the ion bombarding energy range from 100 to 300 eV. It is foun
d that at elevated temperatures beryllium tends to be contaminated wit
h trace amounts of plasma impurities such as carbon, hydrocarbon, oxyg
en and nitrogen even under the energetic deuterium plasma bombardment.
Among these plasma impurities, carbon and hydrocarbon are observed to
form thin films. This carbon deposition effect has made it difficult
to interpret the weight loss data in evaluating the erosion yield. A f
irst-order model has been developed to account for the dynamics of thi
s carbon deposition process and has suggested that some surface chemis
try effect plays an important role. This surface chemistry effect has
been experimentally proved from the observation that carbon deposition
can be avoided only at room temperature. Without impurity deposition,
the beryllium surface after plasma bombardment is found to be cleaner
in oxygen content and smoother in surface topography than the as-rece
ived material. Interestingly, however, even without impurity effects,
the erosion yield data still tend to agree with beryllium oxide data.