碳/碳复合材料导热性能的研究

 对碳/碳复合材料在不同温度下的导热性能进行了研究。研究发现了碳/碳复合材料的导热机理介于金属材料和非金属材料之间,既有声子导热,又有电子导热。在实验温度范围内,导热系数随温度升高而增大。随碳/碳复合材料石墨化程度的增大,晶体微观结构渐趋完整,石墨片层的有序度增加,材料的导热性能增强。对于高密度的碳/碳复合材料,因为晶粒间联通状态良好,热传导载体运动的路径畅通,所以导热系数高。碳纤维及围绕纤维生长的热解碳是热传导的有效通道,所以沿纤维增强方向的导热系数高。

Research on the Thermal Conductivity of C/C Composites

The thermal conductivity of C/C composites at different temperature are discussed.It has been found that the thermal conduction mechanism of C/C composites is intervenient between metal and nonmetal materials, which can be explained by using the phonon heat conduction and the electron heat conduction. The thermal conductivity of C/C composites tends to go up with the increasing of the absolute temperature under the experimental condition. With the increasing of the graphitization degree, the microstructure of the crystal is perfected gradually and the arrangement of laminar graphite is ordered perfectly as well, which leads to the enhancement of the thermal conductivity of C/C composites. C/C composites of high densities have higher thermal conductivity due to their excellent connectivity between crystal particles and smooth channels for the movement of heat conduction carriers. Carbon fibers and pyrocarbon deposited around them are the major paths of heat conduction, so the thermal conductivity increases along the orientation of the carbon fiber.