Abstract: This paper described the tribological properties under different braking speeds of carbon/cabon composites whose microstructures are rough lamina, smooth lamina, mixture of rough lamina and smooth lamina respectively. Optical microscope and scanning electron microscope techniques were used to characterize the microstructures and the worn surfaces. The friction and wear properties of the composites were tested by using a laboratory dynamometer. Results indicate that the friction coefficients of the material a increase to the peak at 15m·s^-1, while the friction coefficients of sample b and c increase to the peak at 20m·s^-1. However, the same temperature of about 250℃ is showed under the worn surface 1mm when the friction coefficient increases to the peak. The weight loss increases with the increase of the braking speeds from 5m·s^-1 to 30m·s-1, but the weight loss of 28m·s-1 is lower than that of 30m·s^-1.

Key words: pyrolytic carbon, microstructure, braking speed, worn surface