The effect of carbon nanotube growing on carbon fibers on the microstructure of the pyrolytic carbon and the thermal conductivity of carbon/carbon composites

Carbon nanotubes were prepared on the surface of carbon fibers in a unidirectional carbon preform and then chemical vapor deposition was used to densify the preform to get a modified carbon/carbon composite. The effects of carbon nanotubes on the microstructure of the pyrolytic carbon and the thermal conductivity of the composite were investigated. Results show that carbon nanotubes on the surface of carbon fibers induce the deposition of ordered pyrolytic carbon around the carbon fibers and adjust the bonding between carbon fibers and pyrolytic carbon. Due to the modification of carbon nanotubes, the thermal conductivity of the composites with nanotubes is greater than that of composites without nanotubes, especially the thermal conductivity perpendicular to the fiber axis.