Roles of carbon blacks in C/C composite of chopped carbon fiber and mesophase binder pitch

This study has analyzed the roles of carbon blacks (CB) in C/C composite. First, the proper amount of CB addition is very effective to increase the density by filling voids among filaments and the pitch. Closer packing through liquid state and uniform shrinkage may increase further the density of the composite. Secondly, the anisotropic units of the matrix texture can be changed into fine ones by adding CB to the composite of CF and MP. This fine texture is expected to bring higher strength. Finally, CB addition can modify the melt fluidity of the matrix binder. Therefore, adequate addition of CB and slower heating may decrease voids during the carbonization and control the generation of cracks during the calcination.