Compatibility of PIP SiCf/SiC with LiPb at 700 deg. C

Silicon carbide fiber reinforced silicon carbide composites (SiCf/SiC) are promising candidate materials for fusion applications. The compatibility of SiCf/SiC composites with liquid LiPb is one of the key issues for fusion technologies. Three-dimensional SiCf/SiC composites were fabricated by polymer infiltration and pyrolysis (PIP) process and β-SiC coating was deposited by chemical vapor deposition (CVD) process. The composites were exposed to static liquid LiPb for 500 h at 700 deg. C. The results showed that the liquid LiPb penetrated through the open pores of the cut surface of the composites and reacted with the matrix and fibers, which caused a weight change and a severe degradation of the mechanical property to the uncoated composites. As for the coated composites, the mechanical property was degraded and the weight increased because of the absorption of LiPb, although the CVD SiC coating was compatible with LiPb and protected fibers and matrix beneath.