TY  - JOUR
AU  - Sakamoto, Ryuichi
AU  - Bernard, Elodie
AU  - Kreter, Arkadi
AU  - Martin, Céline
AU  - Pégourié, Bernard
AU  - Pieters, Gregory
AU  - Rousseau, Bernard
AU  - Grisolia, Christian
AU  - Yoshida, Naoaki
TI  - Surface morphology in tungsten and RAFM steel exposed to helium plasma in PSI-2
JO  - Physica scripta
VL  - T170
SN  - 1402-4896
CY  - Bristol
PB  - IoP Publ.
M1  - FZJ-2018-01634
SP  - 014062 -
PY  - 2017
AB  - Impact of the helium plasma exposure on the surface modification in tungsten and reduced activation ferritic/martensitic (RAFM) steel have been investigated on the linear plasma device PSI-2 assuming the condition of DEMO first wall. In tungsten, a nanoscale undulating surface structure, which has a periodic arrangement, is formed under low temperature conditions below fuzz nanostructure formation threshold ~1000 K. Interval and direction of the undulation shows dependence on the crystal orientation. A large variation in surface level up to 200 nm has been observed among grains at a fluence of $3\times {10}^{26}$ He m−2 showing dependence of the surface erosion rate on the crystal orientation. The {100} plane in which the undulating surface structure is not formed shows the highest erosion rate. This significant erosion is due to the multistage sputtering through impurity. In RAFM steel, sponge-like nanostructure is developed and it grows with increasing helium fluence beyond 1 μm. In the sponge-like nanostructure, a composition change from the base material is observed in which the tungsten ratio increases while the iron ratio decreases showing differences in sputtering ratio depending on the atomic mass.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000417694700007
DO  - DOI:10.1088/1402-4896/aa93a2
UR  - https://juser.fz-juelich.de/record/844182
ER  -