CVI法快速制备C/SiC复合材料

RAPID FABRICATION OF C/SiC COMPOSITES USING CHEMICAL VAPOR INFILTRATION METHOD

为缩短CVI法制备C/SiC复合材料的工艺周期并降低成本 ,研究了CVI工艺过程中沉积温度、MTS(CH3SiCl3)摩尔分数和气体流量对SiC沉积速率和MTS有效利用率的影响 .实验结果表明 :提高沉积温度 ,常压下 110 0℃时增大MTS摩尔分数 (11%→ 19% ) ,都有利于提高SiC沉积速率 ;提高沉积温度和降低反应物气体流量 ,能提高MTS有效利用率 .在优化的工艺条件下 ,预制体的微观孔隙内沉积了致密的SiC基体 ,沉积速率达到 14 2 μm/h左右 ,并有效消除了基体中裂纹的形成 .MTS的有效利用率为 11%～ 2 7%

Influencing factors of deposition temperatures, mole fractions of methyltrichlorosilane (MTS) and reactant gas fluxes in the course of depositing SiC using chemical vapor infiltration (CVI) process were investigated in order to shorten the cycle and reduce the cost of fabrication of C/SiC composite materials. The experimental results show that the deposition rate of SiC matrix increases with increasing deposition temperatures and mole fractions of MTS (rang from 11% to 19%) at atmosphere pressure and 1 100 ℃. Elevation of deposition temperature and decreasing of reactant gas flux increase conversion efficiency of MTS. On the optimum processing conditions,the micro_pores within the preformed specimens are filled with densified SiC matrix at the deposition rate of about 142 μm·h -1 and no cracks are formed. The conversion efficiency of MTS is about 11%-27%.