Physico-chemical stability of SiC/SiC fiber ceramic composite after exposure to fusion-relevant conditions

The physico-chemical stability of SiC/SiC fiber ceramic composite (SiC/SiC/sub f/) in contact with Li/sub 2/O in fusion-relevant conditions has been experimentally studied at 800/spl deg/C in flowing helium (0.1 L/min) containing either 0.1% H/sub 2/ or 100 ppm H/sub 2/O and for exposure times of up to 4032 h. The exposed SiC/SiC specimens have been characterized. The results obtained demonstrate that although the surface coating of the specimens is strongly attacked through chemical corrosion processes, the main physico-chemical characteristics of SiC/SiCf are affected to a limited extent only in the case of He+0.1% H/sub 2/ flowing gas, the bulk material not being attacked.