氧化石墨烯对锂基润滑脂摩擦学性能的影响

目的 研究氧化石墨烯(GO)作为添加剂对润滑脂摩擦性能的影响.方法 将鳞片石墨利用经典的Hummers氧化法氧化得到GO,并表征了GO,再分别以不同的质量分数(0.1％、0.3％、0.5％、1.0％、1.5％)与润滑脂复配.同时增加了空白润滑脂与石墨粉复配的润滑脂作为对比.利用Optimol SRV型摩擦磨损试验机评价...

The Influence of Graphene Oxide on the Tribological Properties of Lithium-based Grease

The effect of graphene oxide (GO) as an additive on the friction properties of greases was studied. The flake graphite was oxidized by the classic Hummers oxidation method to obtain GO, and GO was characterized, and then mixed with grease in different proportions (0.1wt%, 0.3wt%, 0.5wt%, 1.0wt%, 1.5wt%), meanwhile, and we also added the blank grease and the grease compounded with graphite powder as a comparison. The tribological performance was measured by Optimol SRV friction and wear tester, and the 3D profiler and scanning electron microscope (SEM) were used to observe the surface and depth of the worn surface. The chemical state distribution of the elements on the worn surface was analyzed by X-ray energy spectrometer (EDS) and X-rayphotoelectron spectra (XPS). The results indicate that compared with the blank lithium grease, the friction coefficient of the graphite powder-added lithium grease reduced after the friction of the steel/steel friction pair, but as the experiment progressed, the friction coefficient gradually increased, and a wear-out on the surface of the friction pair occurred. While the friction coefficient of the lithium-based grease added with GO was rapidly reduced to about 0.13, which is reduced by 35%, and there was no wear-out on the surface of the friction pair during the experiment time. The SEM and 3D profiler shows the lowest and shallowest wear scar after lubrication with GO grease. At the same time, the EDS shows that the wear scar has more oxygen elements, indicating that GO with oxygen-containing functional groups can be firmly adsorbed on the substrate surface to form a lubricating layer. The XPS confirms that the grease added with graphite and GO has a tribo-chemical reaction with the matrix during the friction test, forming a lubricating film formed by iron oxide. GO as a grease additive can effectively reduce the friction coefficient and the amount of wear, as well as extend the lubrication time and improve the lubricating performance.