湿式铜基粉末冶金摩擦材料黏着损伤研究

Adhesion Damage of Wet Cu-Based Powder Metallurgy Friction Materials

通过离合器试验台研究了铜基粉末冶金摩擦材料的摩擦学性能和黏着损伤特性;采用扫描电子显微镜(SEM)和能谱仪(EDS)分析了表面损伤特征和成分变化.研究了湿式铜基粉末冶金摩擦材料黏着损伤形成发展历程和损伤机理.结果表明:在高于临界功率密度的试验条件下,出现黏着损伤.黏着损伤初期摩擦材料表面出现大量长度200μm^1mm的剥落坑;黏着损伤进展期摩擦片表面形成点状、连续分布撕裂坑;黏着失效期对偶片表面出现显著的过铜现象,扭矩曲线波动异常.摩擦材料发生黏着失效前,在低于临界功率密度的条件下,摩擦性能无明显改变,具有可回复性,仍可继续使用.

The friction performace and the characteristics of adhesion damage of the wet Cu-based friction materials were studied through test bench for clutch sketch. The surface morphology and the element of the damaged surface were analyzed by scanning electron microscope and energy dispersive spectrdmeter,respectively. The results show that friction material suffered adhesion damage when power density was higher than the critical value. There are a lot of the spalling pits with lengths of 200 μm to 1 mm on the surface in the early stage of adhesion damage. There were a lot of continuously distributed punctate tearing pits in the middle stage of adhesion damage. The copper transferred from Cu-based friction materials to steel disc in case of severe adhesion damage,which led to the abnormal to torque curve. When power density was lower than the critical value,the variation of friction performance of the friction materials was insignificant before adhesion failure.