细鳞片与大鳞片膨胀石墨微观结构的比较研究

Comparison of Microstructures in Expanded Graphite With Fine Flakes and Large Flakes

用混酸（浓硫酸、浓消酸）、强氧化剂处理天然鳞片[大鳞片（-60～＋80目），细鳞片（-140～＋160目）]石墨，制得可膨胀石墨，再经高温膨胀得膨胀石墨。采用SEM对两各种膨胀石墨的形貌进行观察分析，发现不同粒度的石墨获得的膨胀石墨其微观孔结构的特征基本相同，但尺寸上存在较大的差异。采用XRD对原料石墨、可膨胀石墨和膨胀石墨的结构作了分析，通过层间距变化、衍射峰出现与消失的情况，判断出不同鳞片大小的石墨在氧化、膨胀过程中发生了相同的变化，从而证明了不同鳞片大小的石墨的膨胀机理是相同的。

Expandable graphite was prepared from natural graphite [ large flake graphite （ -60～＋ 80mesh）, fine flake graphite （ - 140～＋ 160mesh） ] after soaked in acid mixture （ sulfuric acid, nitric acid）, and oxidized in strong oxidant. Then treat the expandable graphite at high temperature to get expanded graphite. It was found by observing the expanded graphite using SEM that the pore structures in the expanded graphite with different granularity are essentially uniform, but differences exist in their size. Microstructures of graphite, expandable graphite and expanded graphite were analyzed by XRD, and it was found by analyzing the variation in doo2 and the diffraction peak that the same changes occurred in graphite with different granularity during the oxidation and expansion. Consequently, it is proved that graphite with different granularity is of the same expansion mechanism.