【摘要】 利用机械化学湿法表面改性工艺对海泡石矿物粉体进行了表面有机包覆和细化处理,得到了在润滑油中具有良好分散稳定性的纳米尺度的海泡石短纤维。借助往复式滑动磨损试验机,以GCr15/45~#钢为摩擦副,考察了表面改性海泡石作为500SN矿物基础油添加剂的摩擦学行为。利用扫描电子显微镜、能量色散谱仪、X射线光电子能谱仪和纳米压痕仪分析了磨损表面的形貌、成分及纳米力学性能,揭示了表面改性海泡石添加剂的减摩润滑机理。结果表明,表面改性海泡石在不同载荷与频率下均表现出良好的抗磨减摩性能,当载荷为100 N、频率为20 Hz时,摩擦因数和45~#钢磨损体积的降幅分别达到69.5%和71.7%。润滑油中部分海泡石粉体直接参与了金属表面复杂的化学反应,形成了由金属氧化物、氧化物陶瓷和石墨等组成的复合摩擦表面膜,该表面膜的形成与海泡石层链状结构及海泡石在不同摩擦条件下解理释氧、晶体结构破坏、活性基团重组密切相关。更多还原

【Abstract】 Sepiolite natural mineral powders were modified and refined by using the mechanochemistry wet modification process, and the nano-scale sepiolite short-fiber were obtained which could be dispersed stably in lubricating oil. Tribological behaviors of the surface modified sepiolite powders as 500 SN mineral oil additives were studied with tribopairs of GCr15/45~# steel by an oscillating wear tester. The morphology, chemical composition and nano-scale mechanical properties of the worn metal surface were analyzed by scanning electron microscopy(SEM), X-ray energy dispersive spectrometry(EDS), X-ray photoelectron spectroscopy(XPS) and instrumented nanoindentation tester.The anti-wear and friction reducing mechanism of the surface modified sepiolite as lubricating oil additives was discussed. Results show that the surface modified sepiolite exhibited excellent tribological properties as lubricating oil additives,which could significantly reduce the friction coefficient and wear volume. Compared with 500 SN oil, the friction coefficient and wear volume of the 45~# steel lubricated by sepiolite oil decreased 69.5% and 71.7% respectively, when the load was 100 N and the frequency was 20 Hz. Partial sepiolite fibers in oil directly participated in the complex tribochemical reactions on the metal surface, and a tribofilm consisting of metal oxide, oxide ceramic, graphite and organics was formed on the worn surface of the 45~# steel. The formation of the film is closely related to(1) the layer structure of sepiolite mineral,(2) its cleavage fracture and release of oxygen under different friction conditions, and(3) the destruction of crystal structure and reorganization of the active groups.更多还原