RESEARCH ON SIC/C PLASMA-FACING FUNCTIONALLY GRADED MATERIALS (FGM) IN CHINA

摘要

Graphite is widely used in present Tokamak facilities as first wall material and C/C composite has been selected as one of the candidate materials of diverter used in ITER. But C-based materials have too high chemical sputtering yield at 600-1000K. and emerge irradiation enhanced sublimation at >1200K under the plasma erosion conditions, causing series contamination problem of plasma. SiC as a low Z advanced ceramic material, has a series of advantages for using as plasma-facing materials, however, it has relatively low thermal conductivity, Since 1997, the FGM design idea for making SiCVC plasma-facing FGM was proposed by the author and research on design and fabrication of SiC/C plasma-facing FGM was conducted in LSCPM with the aim to combine the excellent high temperature properties, low chemical sputtering, high erosion resistance, and low activation after irradiation of SiC with the high thermal conductivity of graphite, to reduce the thermal stress caused by the mismatch of thermal expansion coefficients on the interfaces and to prevent the cracks and failure under serious plasma erosion conditions. The evaluation of plasma-relevant performances was carried out in Southwest Institute Qf Nuclear Physics. The results of the evaluation show the good application perspective of SiC/C FGM as plasma-facing materials in fusion technology.