蛇纹石超细粉体作润滑油添加剂的摩擦学性能

Tribological properties of serpentine ultrafine powders as lubricating oil additives

考察平均粒径为1.0μm的表面修饰蛇纹石超细粉体作为50CC润滑油添加剂对钢/钢摩擦副的润滑性能,研究超细粉体添加量(质量分数)对摩擦学性能的影响。通过对磨损表面的形貌、元素及微观力学性能分析,探讨蛇纹石超细粉体作为添加剂的抗磨、减摩机制。结果表明,蛇纹石超细粉体可显著改善50CC润滑油的润滑性能,降低钢/钢摩擦副的磨损,其最佳添加量为1.5%。蛇纹石超细粉体的减摩润滑机制在于:1)在铁基摩擦表面形成高硬度、低弹性模量的氧化膜,有效降低接触应力和磨粒磨损;2)释放出Al2O3杂质颗粒嵌入摩擦表面并形成微坑和孔洞,起硬质点颗粒增强与微孔储油的双重抗磨、减摩作用;3)摩擦过程中粉体粒径得到细化,形成具有减摩润滑作用的纳米级蛇纹石"第三体"颗粒。

The tribological properties of surface-coated serpentine ultrafine powders（UFPs）, with an average size of 1.0μm, as 50CC oil additives were investigated in the present paper. The morphologies and element distributions of the worn surfaces were characterized by scanning electron microscope（SEM） and energy diffraction spectrum（EDS）, respectively. The nano-indentation test was performed to measure the micro mechanical properties of the worn surface. The results indicate that the friction coefficient of oil and the corresponding wear rate of steel are reduced by dispersing surface-coated serpentine ultrafine powders into 50CC oil. The best tribological properties are obtained when the addition amount of UFPs is 1.5% （mass fraction）. The lubrication mechanism of surface-coated serpentine powders are discussed and attributed to 1） the formation of an oxide film with excellent micro mechanical properties on the worn surface, 2） Al2O3 particles released by serpentine containing impurities are embedded into the worn surface and small pores are formed on the worn surface, which can act as the particles reinforce additives and oil store to decrease the friction coefficient 3） the formation of the third-body nanoparticles of serpentine.