摘要
以多孔C泡沫为预制体,利用液相渗Si工艺制备了C/SiC复合材料。采用酚醛树脂浸渍-裂解工艺对C泡沫预制体的孔隙率进行调整,考察浸渍-裂解周期对C泡沫预制体孔隙率的影响,研究了C泡沫预制体孔隙率对C/SiC复合材料密度、力学性能、组成和结构的影响。结果表明:预制体孔隙率为72%时制备的C/SiC复合材料性能较好,其密度为2.58g/cm3、弹性模量为81.39GPa,抗弯曲强度为83.88MPa;随着预制体孔隙率的降低,复合材料的密度、弹性模量和抗弯曲强度不断降低,预制体孔隙率的降低影响液相Si充分扩散与C反应,造成复合材料内部存在大量闭孔,这是导致C/SiC复合材料性能下降的主要原因。
C/SiC composites were fabricated by liquid silicon infiltration (LSI) method using Carbon foam preform. Firstly, the porosity of carbon foam was changed by pith infiltration-pyrolysis processes and the influence of the infiltration-pyrolysis cycles on the porosity of carbon foam was investigated. Secondly, the influence of the porosity of carbon foams on the density and mechanical properties of C/SiC were discussed. It is found that C/SiC composite derived from carbon foam with 72% porosity has the best elastic modulus (81.4 GPa) and bending strength (83.9 MPa), while its density is 2.58 g/cm3. The C/SiC composites’ density and mechanical properties decrease with the decreasing of carbon foam’s porosity. The result can be explained as follows: with the decreasing of the preform’s porosity, liquid silicon can not diffuse adequately to react with carbon; therefore, there exist many closed pores in the composites.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2011年第S1期485-487,共3页
Rare Metal Materials and Engineering
