不同制动速度下炭布叠层炭/炭复合材料的摩擦磨损行为及机理

用模拟刹车制动的方法探讨了一种炭纤维布叠层炭 /炭复合材料在不同制动速度下的摩擦磨损行为 ,并用扫描电子显微镜对摩擦表面进行了观察和分析。研究结果表明 :在 5m/s的制动速度下 ,该种材料表现出低的摩擦因数 ,但随制动速度升高至 2 0m/s时 ,摩擦因数迅速升高至最大值 0 .4 0 ;当制动速度增大到 2 8m/s或 30m/s时 ,摩擦因数仅略降低至 0 .35 ,该材料表现出优良的高速高能摩擦性能。另一方面 ,制动速度升高至 2 0m/s时 ,即摩擦因数最大时 ,磨损才变得明显 ,而且随制动速度的继续升高 ,磨损呈直线增大。表面显微组织观察表明 ,在较低制动速度下 ,在摩擦表面产生了薄膜 ,对应摩擦因数较低 ,磨损小 ;在 2 0～ 2 5m/s制动速度下 ,摩擦表面形成较厚的表面膜层 ,对应摩擦因数高 ,磨损大 ;在 2 8～ 30m/s制动速度下 ,剧烈的摩擦剪切和氧化作用使摩擦表面严重破坏 ,表面基质炭氧化严重 ,纤维则被拉断或拔出

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.