C/C复合材料预制体结构对摩擦性能的影响

Influence of preform structure on friction properties of carbon/carbon composites

采用整体毡预制体、针刺网胎/无纬布叠层预制体和穿刺预制体,通过化学气相沉积法(CVD)结合液相浸渍法(PIP)制备了C/C复合材料,利用MM1000-Ⅱ型摩擦磨损实验机测试了三种不同预制体C/C复合材料的摩擦性能,采用扫描电子显微镜分别观察了三种C/C复合材料的表面形貌,研究发现预制体结构中纤维排布方式及含量影响C/C复合材料的摩擦系数。相同转速下C/C复合材料的摩擦系数随压力的升高而增大;压力相同的条件下C/C复合材料的摩擦系数随着转速提高而增大;高压高转速下针刺网胎/无纬布制备的C/C复合材料摩擦系数较稳定,整体毡制备的摩擦系数虽小但随转速变化波动较大,穿刺预制体制备的摩擦系数大且波动大,说明穿刺这种增强单元相对较粗大的预制体不适合制备摩擦密封领域的精细结构复合材料。

By using integral felt preform, acupuncture non-woven cloth/mat laminated preform and puncture preform, carbon/carbon composites were prepared by chemical vapor deposition(CVD) and liquid phase impregnation method(PIP).The tribological properties of three different preform C/C composites were systematically tested by MM1000-Ⅱ tribological tester. The fiber and fracture morphology of three kinds of C/C composite materials were observed by scanning electron microscopy. And showing fiber arrangement and volume fraction of preform architecture had an influence on mechanical and friction properties of C/C composites. The results indicate that at the same rotational speed the friction coefficient of C/C composites decreases with the increase of pressure;at the same pressure the friction coefficient of C/C composites increases with the speed increased;Under high pressure and high rotation speed, the friction coefficient of C/C composites prepared by acupuncture non-woven cloth/mat laminated preform is relatively stable. The friction coefficient produced by the integral felt preform is small, but unstable with the change of the rotation speed. The friction coefficient prepared by the puncture preform is large and unstable, which indicates that the relatively coarse preform of the reinforcement unit is not suitable for fine-structured composite materials in the field of friction seals.