高温热处理对C/C复合刹车材料摩擦磨损性能影响的研究

INFLUENCE OF HIGH TEMPERATURE HEAT TREATMENT ON THE FRICTION PROPERTIES OF C/C COMPOSITE BRAKE MATERIALS

分析讨论了高温热处理温度对C/C复合刹车材料石墨化度及摩擦磨损性能的影响规律。研究表明:通过化学气相沉积法制备的C/C复合刹车材料热解碳结构与最终热处理温度无关,均呈现典型的粗糙型结构;从裂解态至2600℃热处理状态,C/C复合刹车材料石墨化度由7.3%提升至67.2%,对应综合导热系数由11.3 W·m^(-1)·k^(-1)增加至50.1 W·m^(-1)·k^(-1);材料摩擦系数随着刹车压力、单位面积能载和速度的升高呈现出逐渐降低的趋势,且相同条件下,石墨化度越高,摩擦系数及磨损率越高。

Graphitization degree is one of the most important parameters,which directly affects the friction and wear performance of C/C composite brake material.High temperature heat treatment is one of the important processes which would affect the graphitization degree of C/C composite brake materials.In this paper,C/C composite brake material is prepared by chemical vapor deposition(CVD)using 2.5D carbon fiber integral acupuncture felt as the reinforcement and natural gas as the air source.The friction performance of the aircraft was simulated under specific braking conditions with different high temperature treatment.The influence of annealing temperature on both graphitization degree and friction performance of C/C composite brake materials is discussed.It is revealed that pyrolytic carbon structure of C/C composite material which is prepared by chemical vapor deposition(CVD)is independent on annealing temperature.However,as annealing temperature raised to 2600℃,both the graphitization degree and heat conductivity coefficient of C/C composite brake material increased significantly.The friction coefficient of brake materials is inversely proportional to the brake pressure,unit area loading and velocity.Furthermore,the graphitization degree is proportional to friction coefficient and wear rate of brake materials.