论文部分内容阅读
Carbon/carbon composites with high thermal conductivity were prepared by hot-pressing method using mesophase pitch-based carbon-fiber and mesophase pitch.This method integrated molding,carbonization,densification and graphitization into one process.The morphology and the microstructure of composites,the influence of hot treatment temperature(HTT)and the den-sification degree on the thermal conductivity were extensively investigated.We found that the carbon/carbon composites showed re-markable anisotropy owing to one-direction design of fibers and carbon matrix parallel to fiber axis.In addition,the conditions of the HTT and the density had a great impact on the conductivity and microstructure of the composites.With the increase of HTT,the crystallite size parameters(La,Lc)and the thermal conductivity of the composites increased while the interlayer spacing(d002)de-creased.More compact internal structure and higher density the composites had,higher thermal conductivity was obtained.The composites reached high performances of the density of 2.09 g/cm3,bending strength of 135 MPa and one-direction thermal con-ductivity of 748 W/m·K at HTT of 2 850 ℃.The temperature dependence of thermal diffusion,specific heat,thermal conductivi-ty and coefficient of thermal expansion were also evaluated.