EVIDENCE FOR GLIDE AND ROTATION DEFECTS OBSERVED IN WELL-ORDERED GRAPHITE FIBERS
EVIDENCE FOR GLIDE AND ROTATION DEFECTS OBSERVED IN WELL-ORDERED GRAPHITE FIBERS
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DOI：
10.1557/jmr.1995.1461
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发表时间：
1995-06-01
影响因子：
2.7
通讯作者：
DRESSELHAUS, MS
中科院分区：
文献类型：
--
作者：
ENDO, M;OSHIDA, K;DRESSELHAUS, MS
采用透射电子显微镜（TEM）和原子力显微镜（AFM）对气相生长碳纤维（VGCF）的晶格面结构进行了图像分析，研究了经热处理的气相生长碳纤维（VGCF）的结构特征。通过二维快速傅里叶变换处理有序石墨纤维（在2800 ℃下热处理的VGCF）的TEM晶格图像，显示与002和100晶格平面相关的尖锐亮点。热处理后的VGCF由球形壳组成，TEM点阵图像中的长和短条纹结构分别反映了002和100点阵平面。通过这种分析，可以直观地、定量地获得有关晶格结构的新事实。002晶格平面保持并且沿纤维轴彼此沿着高度平行，保持3.36埃的均匀层间距。观察到100个晶格平面相对于平面法线与002个晶格平面形成多个倾斜角，这是由相邻石墨烯层的滑动引起的。这项工作直观地展示了石墨堆叠的共存，以及相邻石墨烯层的滑动，滑动角为约3-20度。这些滑移面是热处理VGCF中的主要堆叠缺陷之一。另一方面，乱层结构的证据，建议由AFM观察。提出了石墨化过程中石墨结构、滑移结构和乱层结构共存的结构模型，作为向三维堆积过渡的过渡阶段，这些结构特征也可能出现在普通碳和碳纳米管中。
New structural features observed in heat-treated vapor-grown carbon fibers (VGCF's), produced by the thermal decomposition of hydrocarbon vapor, are reported using image analysis of the lattice plane structure observed by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The TEM lattice image of well-ordered graphite fibers (heat-treated VGCF's at 2800 degrees C) was treated by a two-dimensional fast Fourier transform, showing sharp bright spots associated with the 002 and 100 lattice planes. The heat-treated VGCF's consist of a polygonally shaped shell, and the long and short fringe structures in the TEM lattice image reflect the 002 and 100 lattice planes, respectively. From this analysis, new facts about the lattice structure are obtained visually and quantitatively. The 002 lattice planes remain and are highly parallel to each other along the fiber axis, maintaining a uniform interlayer spacing of 3.36 Angstrom. The 100 lattice planes are observed to make several inclined angles with the 002 lattice planes relative to the plane normals, caused by the gliding of adjacent graphene layers. This work visually demonstrates coexistence of the graphitic stacking, as well as the gliding of the adjacent graphene layers, with a gliding angle of about 3-20 degrees. These glide planes are one of the dominant stacking defects in heat-treated VGCF's. On the other hand, turbostratic structural evidence was suggested by AFM observations. The structural model of coexisting graphitic, glide, and turbostratic structures is proposed as a transitional stage to perfect three-dimensional stacking in the graphitization process, These structural features could also occur in common carbons and in carbon nanotubes.