By taking axial carbon rods 4D preform woven with two kinds of T300 grade PAN based carbon fiber
made in China as reinforcement and high temperature coaltar pitch as matrix precursor, the C/ C composites with a
density up to 1. 95 g/ cm3 were prepared by using combined impregnationcarbonization and graphitization techniques.
Thermal conductivity of the C/ C composites from RT to 800益and the influencing factors were discussed. The results
show that thermal conductance of the C/ C composites is decreased with increasing of the temperature under the experimental condition. Because of the own features of raw materials and the directivity of preform, the thermal conductivity
of the C/ C composites along radial direction is higher than that of axial direction. C/ C composites with higher density, lower porosity and higher graphitization degree have higher thermal conductivity due to their excellent connectivity
between crystal particles and gradually perfected crystal microstructure. The thermal conductivity of the C/ C composites with low pressure heat treatment as its final process is higher than that after high pressure carbonization. The thermal conductivity of C/ C composites prepared by T300 carbon fibers made in China is similar to that of the C/ C composites prepared by Toray T300 carbon fibers.