Frictional and wear behaviors of C/C composites from carbon fibre cloth at different braking speeds

Frictional and wear behaviors of C/C Composites from a carbon fiber cloth were investigated with an inertial braking apparatus at different braking speeds. The frictional surfaces were examined with SEM. The results show that at the speed of 5?m/s, the friction coefficient is very low (0.18). But it rapidly increases to the maximum of 0.40 at the speed of 20?m/s. When the speed further increases to 28?m/s or 30?m/s, the friction coefficient decreases only a little to 0.35, demonstrating this material has excellent high speed and high energy braking properties. On the other hand , the wear becomes evident at the braking speed of 20?m/s and increases linearly with increasing the speed. Results of the SEM observation show that at lower speeds, a smooth friction film is formed on the worn surfaces, correlating to lower friction coefficients and wear rates. At the speed of 20?m/s or 25?m/s, a thicker friction film is formed, correlating to higher friction coefficients and wear rates. When the speed increases to 28?m/s or 30?m/s, the strong friction shear and severe oxidation destroys the worn surface, and even fibers are fractured or pulled out.