Microstructure features of polycrystalline diamond synthesized directly from graphite under static high pressure
Microstructure features of polycrystalline diamond synthesized directly from graphite under static high pressure
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DOI：
10.1023/b:jmsc.0000011496.15996.44
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发表时间：
2004-01-15
影响因子：
4.5
通讯作者：
Inoue, T
中科院分区：
文献类型：
--
作者：
Sumiya, H;Irifune, T;Inoue, T
最近，以石墨为原料，在静高压下直接转化合成了超硬多晶金刚石。本文描述了这样形成的多晶金刚石的微观结构特征。透射电子显微镜和电子衍射仪表明，聚晶金刚石具有均匀的精细结构和片层结构的混合织构。前一种结构由直径几十纳米的细粒金刚石颗粒组成，这些颗粒是随机取向的。后一种结构具有弯曲的钻石层，这可能反映了原始材料的局部层状石墨的变形形状。实验结果表明，均匀细小结构的金刚石颗粒是在扩散过程中由石墨转变而来的，而片层结构的金刚石层则是由石墨通过六方金刚石相在马氏体过程中形成的。还注意到，在接近2700摄氏度的高温下，出现了显著的晶粒生长，片层结构被分段形成新的晶界。(C)2004年克鲁沃学术出版社。
Recently, ultra-hard polycrystalline diamond was synthesized from graphite by direct conversion under static high pressure. This paper describes the microstructure features of thus formed polycrystalline diamond. Transmission electron microscopy and electron diffraction have revealed that the polycrystalline diamond has a mixed texture of a homogeneous fine structure and a lamellar structure. The former structure consists of fine-grained diamond particles of several tens of nanometers across, which are randomly oriented. The latter structure has bending diamond layers, which may reflect deformed shapes of locally layered graphite of starting material. The experimental results suggest that diamond particles in the homogeneous fine structure are transformed from graphite in the diffusion process, while diamond layers in the lamellar structure are formed in the martensitic process from graphite via the hexagonal diamond phase. It is also noted that significant grain growth occurred at a high temperature of similar to2700 degreesC, and the lamellar structure was segmentalized to form new grain boundaries. (C) 2004 Kluwer Academic Publishers.