宽温域中碳纤维导热特性研究

Study on thermal conductivity of carbon fiber in wide temperature range

中文关键词: 碳纤维  热扩散系数、导热系数  拉曼光谱  驰豫时间  热阻

英文关键词: carbon fiber, thermal diffusivity, thermal conductivity, Raman spectrum, relaxation time, thermal resistance

中文摘要:

      碳纤维作为一种被广泛应用的微纳米材料,对其热导率的测量研究一直被作为对碳纤维性能研究的重要内容。在利用氦气的气体液化技术的基础上搭建的稳定低温实验环境中,基于瞬态电热法对处于290K到10K温度范围内的碳纤维样品的热导率进行研究。实验发现,当实验温度低于某一特定温度后,材料的热扩散率表现出与声子学理论分析相反的实验结果。通过引入热扩散系数倒数这一理论研究声子热阻在低温下的变化,分析得出，当实验环境温度低于某一特定温度后,低温会造成碳纤维材料内的石墨微晶体结构会发生变化,从而造成材料热扩散率下降。

英文摘要:

      Carbon fibers are widely used as micro- and nano-materials. The measurement of thermal conductivity of carbon fibers has been regarded as an important part of the research on the properties of carbon fibers. The thermal conductivity of carbon fiber samples in the temperature range of 290K to 10K was studied by the transient electro-thermal method in a stable low-temperature experimental environment based on helium gas liquefaction technology. It is found that when the experimental temperature is lower than a certain temperature, the thermal diffusivity of the material exhibits contray to the phonon thermal resistance at low temperature. By introducing the reciprocal of thermal dffusivity to study on the variation of phonon thermal resistance at low temperature, it is concluded that the graphite microcrystal structure in carbon fiber material will change when the experimental ambient temperature is lower than a certain temperature, which will result in the decrease of thermal diffusivity of the material.