Interfacial reaction and diffusion control between SiC and F82H steel

SiC/SiC composite and reduced activation ferritic/martensitic (RAFM) steels such as F82H are being considered as candidate structural materials for fusion reactors. Controlling the interfacial reaction between SiC and F82H is important for the development of advanced concept designs, e.g. dual coolant lead–lithium blanket. In this work, the interfacial stability between SiC and F82H was investigated. The results indicated that SiC is chemically incompatible with F82H at elevated temperature. Cracking was also observed in SiC due to the generation of large residual stress. To obtain a thermally stable interface between SiC and F82H, a proper diffusion barrier that not only suppresses the intense interfacial reaction but also reduces the residual stress between them is necessary, and three low activation materials of Si, Cr, and W for this purpose were evaluated in this paper. The results revealed that W is the most efficient diffusion barrier, although it reacted with F82H and formed brittle phase.