鳞片石墨含量对地铁集电靴用铜基粉末冶金材料性能的影响

Effect of flake graphite content on the properties of copper-based powder metallurgy materials for subway collector boots

采用粉末冶金技术制备了鳞片石墨含量分别为2%、3%、4%、5%、6%的铜基粉末冶金摩擦材料并测定其力学性能;使用MM-1000Ⅲ型摩擦磨损试验机测试其摩擦磨损性能;使用扫描电镜观察其摩擦表面及冲击断面的微观组织形貌并分析其摩擦磨损及冲击断裂机理。结果表明:随鳞片石墨含量的增加,材料的冲击韧性、布氏硬度、抗拉强度下降,材料的电阻率上升;在相同压力和配置惯量的试验参数下,随着鳞片石墨含量的增加材料摩擦因数和磨损率下降,3%石墨含量的摩擦材料样品摩擦因数变化最稳定,同时材料的摩擦磨损机理主要由剥落磨损转变为黏着磨损和磨粒磨损;材料冲击韧性随鳞片石墨含量增加而降低,冲击断面韧窝的成形受材料组织孔隙数量和位错塞积的影响。

Copper based powder metallurgy friction materials with flake graphite content of 2%, 3%, 4%, 5% and6% were prepared by powder metallurgy technology and their mechanical properties were measured.The MM-1000Ⅲ friction and wear testing machine was used to test its friction and wear performance.Scanning electron microscopy(SEM) was used to observe the microstructure of the friction surface and impact section and analyze the mechanism of friction wear and impact fracture.The results show that the impact toughness, Brinell hardness and tensile strength decreases with the increasing of flake graphite content, and the resistivity of the material increases.With the increasing of flake graphite content, the friction coefficient and wear rate of the material decrease under the same pressure and inertia.The impact toughness of the material decreases with the increasing of flake graphite content. The formation of impact section dimples is affected by the number of tissue pores and dislocation plug.