CVD碳涂层对SiC纤维性能的影响

采用化学气相沉积的方法,在SiC纤维表面沉积了一层C涂层,通过拉伸实验对涂C前后的SiC纤维强度进行比较分析,用扫描电子显微镜对其形貌进行观察。结果表明,表面涂C使SiC纤维表面致密光滑,弥合了纤维表面的孔隙、微裂纹等缺陷。表面涂C后SiC纤维的强度比涂C前提高了1000 MPa左右,且明显减少了纤维强度的分散性,Weibul模数明显提高。本文的C涂层厚度不到1μm,说明仍可进一步优化CVD工艺。

Influence of CVD Carbon Coating on SiC Fiber Property

A thin layer of carbon was coated onto SiC fiber through chemical vapor deposition(CVD).The tensile strength of the fiber with and without C-coating was measured and the morphology of the fiber was observed by using scanning electron microscope.It was found that the C-coating of the SiC fiber makes the surface of the fiber dense and smooth.The micro-holes and micro-cracks on the surface of the SiC fiber disappear after carbon deposition.The tensile strength of the fiber after carbon deposition is 1000MPa larger than that before carbon deposition.The distribution of the tensile strength is more concentrated and the Weibull modulus increases remarkably when the SiC fiber receives.The CVD process can be improved further because the C-coating of the SiC fiber is too thin and the thickness is less than 1μm in the work presented in the paper.