Hydrogen Retention Properties of SiC/SiC Composites as Plasma Facing Material of Fusion Reactor

Abstract

In order to examine the deuterium retention properties of SiC/SiC compositess, the deuterium ion irradiation was conducted followed by a thermal desorption spectroscopymeasurement. The deuterium retained was desorbed in forms of HD, D2, HDO, CD4 and C2D4. The ratio of the amount of desorbed hydrocarbons to the total amount of retained deuterium was approximately 6%, which is much smaller, compared with the case of carbon material. Namely, we confirmed that the chemical erosion of SiC/SiC composites isquite small. In the D2 desorption spectra, two desorption peaks appeared. The lower and higher temperatures peaks were regarded to be due to detrappings of Si-D and C-D bonds, respectively. The ratio of deuterium amount desorbed at highertemperature decreased with increase of the deuterium fluence.This behavior could be explained that the carbon content at thesurface is reduced by the selective sputtering due to deuteriumions.