球磨纳米碳粉的表征和光声光谱

Characteristic and Photoacoustic Spectroscopy of Nano-sized Graphite

用球磨法制备纳米碳粉并进行表征测量,光声光谱的研究指出:随着颗粒尺寸的减小,样品的光声响应减弱,其原因是热扩散过程中的量子尺寸效应,即平均自由程的减小,系统自由度和热振动能的增加。纳米材料高密度晶界的存在也可能对热波产生大的散射,导致热阻增加,使光声信号减弱。

The characteristic measurement of nanosized carbon powder prepared by milling in Ar gas was carried out. It was observed from photoacoustic (PA) spec-troscopy that the response of PA signal decreased as the particle size of sample decreased because of the quantum size effect in heat diffusion i. e. the shorter average free path, the bigger dimension and vibrational energy of the system. The hea't wave function was affected by the higher boundary density of nano-sized materials.