摩擦磨損行為及機(jī)理
(中南大學(xué) 粉末冶金研究所，粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，
長沙 410083)
摘 要: 用模擬剎車制動(dòng)的方法探討了一種炭纖維布疊層炭/炭復(fù)合材料在不同制動(dòng)速度下的摩擦磨損行為，并用掃描電子顯微鏡對摩擦表面進(jìn)行了觀察和分析。研究結(jié)果表明：在5m/s的制動(dòng)速度下，該種材料表現(xiàn)出低的摩擦因數(shù)，但隨制動(dòng)速 度升高至20m/s時(shí)，摩擦因數(shù)迅速升高至最大值0.40；當(dāng)制動(dòng)速度增大到28m/s或30m/s時(shí)，摩擦因數(shù)僅略降低至0.35，該材料表現(xiàn)出優(yōu)良的高速高能摩擦性能。另一方面，制動(dòng)速度升高至20m/s時(shí)，即摩擦因數(shù)最大時(shí)，磨損才變得明顯，而且隨制動(dòng)速度的繼續(xù)升高，磨損呈直線增大。表面顯微組織觀察表明，在較低制動(dòng)速度下，在摩擦表面產(chǎn)生了薄膜，對應(yīng)摩擦因數(shù)較低，磨損小；在20～25m/s制動(dòng)速度下，摩擦表面形成較厚的表面膜層，對應(yīng)摩擦因數(shù)高，磨損大；在28～30m/s制動(dòng)速度下，劇烈的摩擦剪切和氧化作用使摩擦表面嚴(yán)重破壞，表面基質(zhì)炭氧化嚴(yán)重，纖維則被拉斷或拔出。
關(guān)鍵字: 炭/炭復(fù)合材料；炭布疊層；制動(dòng)速度；摩擦磨損
C/C composites from carbon fibre
cloth at different braking speeds
JI Dong-ying, PENG Jian-xin
（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
