B、Si改性炭/炭复合材料及其摩擦磨损特性

以低密度的C/C复合坯体为预制体,分别采用反应熔渗(RMI)、化学气相沉积(CVD)、浸渍-原位反应技术对其进行陶瓷改性.结果表明:改性陶瓷分别以SiC和c-BN的形式渗入C/C复合坯体内.摩擦试验结果表明:采用RMI技术制备的C/C-SiC复合材料摩擦因数较高,高达0.3到0.9;采用CVD技术制备的C/C-SiC复合材料的摩擦因数在0.20～0.36之间;而采用浸渍-原位反应技术制备的c-BN改性C/C复合材料的摩擦因数较低,为0.10～0.20.SEM观察表明:采用RMI技术制备的C/C复合材料的摩擦表面粗糙、未形成完整的摩擦膜,而采用另两种技术制备的C/C复合材料均形成了较完整、致密的摩擦膜.

C/C composites modified by B, Si and their friction and wear properties

The low density C/C composites were modified by B and Si using reaction melt infiltration (RMI), chemical vapour deposition (CVD) and impregnation and in-situ reaction. The results show that the modified ceramics are successfully added in the matrix carbon as SiC or c-BN. The C/C-SiC modified by RMI has high friction coefficient which reaches 0.30-0.90. The friction coefficient of C/C-SiC modified by CVD changes in 0.20-0.36, while the composites modified by c-BN using impregnation and in-situ reaction hold the lowest friction coefficient, which is 0.10-0.20. The wear surfaces of the RMI-modified composites are very rough without any integrated friction film, while the wear surfaces of the other two composites are compacted and integrated.