摘要
分别以高纯石墨、细颗粒石墨及低密度的C/C复合材料为基体,以MTS为SiC的先驱体原料,采用化学气相沉积工艺制备SiC涂层.通过扫描电镜(SEM)观察CVD SiC涂层的微观形貌,利用X射线衍射仪(XRD)分析其晶体结构.研究发现,在不同沉积基体上沉积的SiC晶体形貌不同.以高纯石墨为基体的试样表面基本不存在SiC晶须的生长特征;以细颗粒石墨为基体的试样的表面发现了SiC晶须的生长特征,且基体内部的SiC晶体具有一定的CVI特征,即靠近基体内部沉积的SiC晶体逐渐由SiC晶须变为SiC纳米线;以C/C复合材料为基体的试样内部和表面沉积的SiC晶体表现出多元化的形貌,以层状SiC晶体和SiC晶须为主,主要是由基体材料微观结构的多元化而导致沉积的微区气氛有所不同造成的.
Silicon carbide coatings were fabricated on high-pure graphite, fine-grain graphite and low density C/C composite by chemical vapor deposition, used MTS as the SiC-source. The morphologies and crystalline structures of the SiC were characterized by scanning electron microscopy and X-ray diffraction. The results showed that the morphologies of SiC crystals deposited on different matrixes are different.There is no SiC crystal whisker exists basicallyon high-pure graphite. The grow feature of SiC crystal whisker was found on the surface of fine-grain graphite as well as CVI feature inside the matrix. And SiC crystals deposited near the matrix gradually changed from SiC whiskers to SiC nanowires. As to C/C composite, SiC crystal showed multi-choice, mainly included lamellar SiC crystal and SiC crystal whisker, as a result of difference of micro-zone atmosphere in matrix microstructure.
引文
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