高温处理对中间相沥青基炭纤维结构与热导率的影响

The evolution of microstructure and thermal conductivity of mesophase pitch-based carbon fibers with heat treatment temperature

摘要: 采用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、拉曼光谱仪（Raman）及X射线衍射仪（XRD）考察了中间相沥青基炭纤维在不同热处理温度下的结构及形貌变化，并采用3 ω法对经不同温度处理后的纤维热导率进行了表征。结果表明，中间相沥青基炭纤维的石墨化度与热导率随着热处理温度的升高而增大，经3 000℃处理后纤维的热导率最高可达518 W/m·K。此外，还探讨了中间相沥青基炭纤维结构、热导率及热处理温度之间的相互关系，发现中间相沥青炭纤维的石墨化过程存在3个阶段，在不同温度区间内分别对应石墨微晶的生长和取向。

Abstract: The evolution of microstructure and morphology of mesophase pitch-based carbon fibers (MPCFs) with heat treatment temperature (HTT) was investigated by SEM, TEM, Raman spectroscopy and XRD. The thermal conductivity of the MPCFs was examined by a modified 3ω method. Results indicate that the degree of graphitization and the thermal conductivity of the MPCFs increase with HTT. The thermal conductivity of the MPCFs reaches 518 W/m·K at a HTT of 3000℃. The thermal conductivity of MPCFs varies linearly with HTT in two distinct ranges, 1000-2000 and 2300-3000℃, that respectively correspond to the growth and orientation of graphite crystallites.