Tribological properties of cenosphere and carbon fiber reinforced polyimide composites

Polyimide (PI) composites reinforced by cenosphere and carbon fiber (CF) were prepared by compression molding. The effects of load, sliding speed and content of cenosphere on tribological performances of the composites were evaluated on MRH-3 ring-on-block wear tester, and the wear morphology and mechanism were also analyzed. The results show that carbon fiber and cenosphere have the synergistic effect on the tribological properties of cenosphere-carbon fiber/polyimide composites; the tribological properties of the composite filled by cenosphere and carbon fiber were superior than those filled by single incorporation of cenosphere or carbon fiber. The content of cenosphere has little impact on the friction coefficient of cenosphere-carbon fiber/polyimide composites, but the wear rate declines with the increase of load and then improves. The 15% cenosphere-10% carbon fiber(mass fraction)/polyimide composite exhibits the lowest friction coefficient and wear rate. As an increase of the sliding speed, the friction coefficient of the composites decreases and the wear rate increases. The friction coefficient of the composite declines with the increase of load and then rises, but the wear rate increases with the increase of load. It is found that the main wear mechanism of the cenosphere-carbon fiber/polyimide is abrasive wear in the case of lower load, and shifts to the adhesive wear and abrasion while under higher load.