C芯SiC纤维制备技术研究

在自行设计制造的直流电阻加热CVD装置上制备出C芯SiC纤维,C芯SiC比W芯具有更高的力学性能,更好的界面相容性,更低的密度,成为制备SiC/Ti基复合材料的最佳增强体。研究CH3SiHCl2-CH3SiCl3-H2-Ar体系中在C芯表面化学气相沉积SiC涂层工艺,考察沉积温度,H2]/silane],气流量,Ar气流量对化学气相沉积SiC涂层的结构、性能的影响。并对涂层表面形貌及结构成分进行SEM,XRD,raman,AES分析。结果表明:在温度1200℃,H2]/silane]=1.4,气体流量4.89L/min,稀释气体0.2L/min时,纤维拉伸强度最好为3392MPa。其中纤维的性能对沉积温度,H2]/silane]最敏感。

Study on Preparation of C-Core SiC filaments by CVD Process

C-core SiC filaments were prepared by CVD process using DC electrical heating. C-core SiC filaments possesses higher mechanical properties, better compatibility on the interface, and lower density than W-core SiC filaments, so C-core SiC filaments are the best reinforcements for preparing the SiC/Ti composites. The C-core SiC filaments coating by CVD process were studied by SEM, XRD, raman, and AES in CH3SiHCl2-CH3SiCl3-H2-Ar system. The influences of temperature, H2]/silane] , flow rate of carrier gas and dilute gas on the microstructure of CVD SiC coating were investigated. The results show that the optimum condition for the C-core SiC filaments with tensile-strength 3392 MPa are 1200 ℃, H2]/Silane]=1.4, total gas flow rate 4.89 L/min, and diluent flow rates 0.2 L/min. The reaction temperature and H2]/silane] are the most sensitive factors for the properties of C-core SiC filaments.