摩擦磨损行为及机理
(中南大学 粉末冶金研究所，粉末冶金国家重点实验室，
长沙 410083)
摘 要: 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20m/s时，摩擦因数迅速升高至最大值0.40；当制动速度增大到28m/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20m/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20～25m/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28～30m/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。
关键字: 炭/炭复合材料；炭布叠层；制动速度；摩擦磨损
C/C composites from carbon fibre
cloth at different braking speeds
（State Key Laboratory for Powder Metallurgy,
Powder Metallurgy Research Institute,
Central South University，Changsha 410083, China）
Abstract: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 5m/s, the friction coefficient is very low (0.18). But it rapidly increases to the maximum of 0.40 at the speed of 20m/s. When the speed further increases to 28m/s or 30m/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 20m/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 20m/s or 25m/s, a thicker friction film is formed, correlating to higher friction coefficients and wear rates. When the speed increases to 28m/s or 30m/s, the strong friction shear and severe oxidation destroys the worn surface, and even fibers are fractured or pulled out.
Key words: C/C composite; carbon fibre cloth; braking speed; friction and wear
