摘要
以针刺网胎无纬布为预制体,采用化学气相沉积(CVD)和树脂浸渍/炭化(IC)制成不同密度的炭/炭(C/C)多孔体,然后在温度为1650℃、1800℃时进行熔融渗硅(LSI)制备C/C-SiC复合材料。采用金相显微镜观察材料渗硅前后形貌,并结合熔融渗硅机理进行分析;研究多孔体密度、反应温度等因素对熔渗效果的影响。结果表明,低密度的C/C多孔体开孔率高,比表面积大,液态Si易于渗入,生成更多SiC,致密效率高;1800℃时进行熔融渗硅效果更好,所得材料的弯曲强度最高可达225 MPa。
Porous C/C preforms with different densities were prepared by chemical vapor deposition （CVD） and different periods of resin impregnation/carbonization （IC）, and then liquid silicon was infiltrated into it at 1650 ℃ and 1800 ℃, producing a C/C-SiC composite. The morphology of porous C/C preform and C/C-SiC was observed by means of metallographic microscope, and was analyzed by the mechanism of LSI. The porous bulk density, reaction temperature and other factor on infiltration effect were investigated. The results showed that porous C/C preform with low density, high open porosity and large specific surface area to silicon infiltration was more beneficial to infiltration of liquid silicon, leading to formation of more SiC, then got higher efficiency of dense. The molten silicon was infiltrated into flexural sample at 1800 ℃, which could obtain better effect and the maximum flexural strength of the product could reach 225 MPa.
基金
国家自然科学基金(51202233)
