C/C素坯密度对GSIC/C-SiC复合材料摩擦磨损性能的影响

采用气相渗硅工艺(GSI)制备C/C-Si C复合材料,研究了C/C素坯密度对GSI C/C-Si C复合材料物相组成与摩擦磨损性能的影响,分析了C/C-Si C复合材料的制动过程,并归纳了其摩擦磨损机理。结果表明,随着C/C素坯密度的增大,GSI C/C-Si C复合材料的密度呈递减趋势,且C含量和开气孔率逐渐增加,而Si C含量和残余Si含量逐渐减少;自对偶条件下,复合材料的平均摩擦系数、磨损率均呈现先增大后减小的趋势,当C/C素坯密度为1.25g/cm3时有最大值,而制动稳定系数则不断增大。GSI C/C-Si C复合材料的制动过程是犁沟效应和粘着效应共同作用的结果,制动初始阶段和刹停阶段以犁沟效应为主,中间阶段以粘着效应为主。

Effect of C/C Green Density on Friction and Wear Properties of C/C-SiC Composites Prepared by GSI Process

C/C-SiC composites were prepared by gaseous silicon infiltration (GSI) using C/C as green body. The effect of C/C density on the phase composition, friction and wear properties was studied. Through analyzing the braking process, the friction and wear mechanism of C/C-SiC composites is discussed in detail. The results show that, with C/C green density increasing, the density of GSI C/C-SiC composites decreases, and C content and open porosity gradually increase, while the contents of SiC and residual Si decrease. Under the self-dual circumstances, the average friction coefficient and wear rate of the composites increase firstly and then decrease, however, the braking stability coefficient increases continuously. When the density of C/C is 1.25g/cm3, the average friction coefficient and wear rate reach the maximum value. The braking process mechanism of GSI C/C-SiC composites is controlled by furrow effect and adhesion effect. The furrow effect is the main part in initial stage and late stage of braking, while the adhesion effect is the main factor in the middle stage.