Al_(2)O_(3)增强粉末冶金铜基摩擦材料摩擦磨损性能研究

Study on Friction and Wear Properties of Powder Metallurgy Copper Based Friction Materials Reinforced by Al_(2)O_(3)

为提高铜基粉末冶金摩擦材料的耐磨性及制动效果,使用粉末冶金法(PM)制备氧化铝增强铜基摩擦材料,采用布氏硬度计、扫描电子显微镜(SEM)、能量色散光谱仪(EDS)等测试手段以及摩擦磨损实验,研究氧化铝的掺杂对摩擦材料微观组织和摩擦行为的影响。结果表明:在制备的铜基摩擦材料中,氧化铝硬质颗粒在铜基体中分布均匀,由于硬质相的存在所形成位错钉扎效应对复合材料的硬度有大幅的提升,而对材料的密度有一定的消极作用。摩擦实验结果显示,氧化铝可以提高材料的摩擦因数并增强其耐磨性;且随着载荷的增大Al_(2)O_(3)-Cu复合材料的摩擦因数较高且稳定性较好,磨损率有明显的降低,表明氧化铝的掺杂对铜基材料有显著的增强效果。通过光学显微镜以及EDS分析得出,Cu基材料的主要磨损机制为氧化磨损和黏着磨损,而Al_(2)O_(3)-Cu材料的磨损机制为氧化磨损和磨粒磨损组成的混合磨损。

In order to strengthen the wear resistance and braking effect of copper-based powder metallurgy friction materials,the copper-based friction materials reinforced by alumina were prepared by powder metallurgy(PM) method.The effects of alumina doping on the microstructure and friction behavior of friction materials were studied by means of Brinell hardness tester,scanning electron microscopy(SEM),energy dispersive spectrometer(EDS) and friction and wear experiments.The results show that the alumina hard particles are uniformly distributed in the copper matrix of the copper-based friction materials.The pinning effect of dislocation caused by the existence of the hard phase has a significant increase in the hardness of the composites,but has a certain negative effect on the density of the composites.The friction experimental results show that alumina can improve the friction coefficient and enhance the wear resistance of the material.With the increase of load,the friction coefficient of Al_(2)O_(3)-Cu composites is higher and the stability is better,and the wear rate is significantly reduced,indicating that the doping of alumina has a significant enhancement effect on copper-based materials.Through optical microscope and EDS analysis,it is found that the main wear mechanism of Cu-based material is oxidation wear and adhesive wear,while the wear mechanism of Al_(2)O_(3)-Cu material is mixed wear of oxidation wear and abrasive wear.