热蒸发工艺中碳源微观结构对SiC晶须生长的影响

Influence of carbon source microstructure on the growth of SiC whisker via thermal evaporation

通过高温热蒸发硅粉工艺,以鳞片石墨、膨胀鳞片石墨、纳米炭黑和微米炭黑为碳源制备SiC晶须,研究了碳源结构对SiC晶须生长的影响。采用X射线衍射、扫描电镜和透射电镜等手段对不同碳源和制得样品的微观形貌和结构进行表征。结果表明:SiC晶须更容易在膨胀鳞片石墨和纳米炭黑表面生长,碳源具有乱层堆垛石墨结构和合适的晶粒尺寸是SiC晶须生长的决定性因素。

Using graphite flake, expanded graphite flake, nanosized pyrolytic carbon black and microsized thermal carbon black as carbon sources, SiC whiskers were prepared by thermal evaporation of silicon powders at high temperature and the effect of carbon source microstructure on the growth of SiC whiskers was investigated. The morphology and microstructure of different carbon sources and the as-obtained product were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy.The results showed that SiC whiskers was prefer to grow on the surface of expanded graphite flake and nanosized pyrolytic carbon black.The critical factors for promoting the formation of SiC whiskers were that the carbon sources should possess turbostratically stacked graphite structure and appropriate grain size.