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 C2H4/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 similar to 6-8 mu m diameter supporting Ni and Fe nanoparticles. A "porous nanotissue" which interconnects the original fibers is initially generated. At later stages a more compact CIC composite material is formed on a laboratory scale, which shows a high graphitization degree.