Connecting Carbon Fibers by Means of Catalytically Grown Nanofilaments:  Formation of Carbon−Carbon Composites

The progressive formation of carbon/carbon (C/C) composites via a catalytic method by covering carbon fibers with a carbon matrix using C 2 H 4 /H 2 feedstock is investigated by SEM, TEM, and AFM microscopies and by XRD analysis. In the initial stages, intersecting nanofilaments of about 40−50 nm diameter are formed under relatively mild conditions at the surface of smooth carbon fibers with ∼6−8 μm diameter supporting Ni and Fe nanoparticles. A “porous nanotissue” which interconnects the original fibers is initially generated. At later stages a more compact C/C composite material is formed on a laboratory scale, which shows a high graphitization degree.