Abstract The research presented in this paper aims to investigate the effectiveness of different surface roughness and lubrication conditions on the interfacial tribological properties between silicon carbide (SiC) and silicon nitride (Si3N4) ceramics, particularly for providing insight into the mechanisms of how graphene reduces the friction and wear rate. The worn groove topography and surface composition were characterised in detail with 3D laser measuring microscopy and X-ray photoelectron spectroscopy. The tribological test results on the UMT-TriboLab show that a smooth initial surface is more likely to obtain a low friction coefficient and wear rate under water lubrication. The proper initial surface roughness for SiC and Si3N4 ceramics is approximately Ra 10 nm, and it will be lower in an alcohol or graphene aqueous solution. A large load does not worsen the tribological behaviour of a Si3N4 ball sliding against a SiC disk, and it reduces the friction coefficient and wear rate. Among the five lubrication states of dry friction, dry graphene lubrication, water lubrication, graphene solution lubrication, and self-developed graphene lubrication, the self-developed graphene lubricant can exhibit an ultra-low friction coefficient of 0.009 and ultra-low wear rate of 1.69 × 10−7 mm3/N·m. The excellent tribological property of the graphene-coated ceramic surface helps the prepared lubricant to decrease the friction coefficient effectively. Furthermore, the graphene film can protect the SiC from being oxidised by water under the tribo-activated action, and therefore, lead to ultra-low wear rate under low friction condition. Alcohol improves the tribological property of the self-developed graphene lubricant, mainly because of the good wettability between graphene and ethanol. The self-developed graphene lubricant can be applied in water-lubricated ceramic bearings and motorised precision spindles.

中文翻译：

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自主研发石墨烯润滑剂对碳化硅/氮化硅界面摩擦学行为的影响

摘要 本文提出的研究旨在研究不同表面粗糙度和润滑条件对碳化硅 (SiC) 和氮化硅 (Si3N4) 陶瓷之间界面摩擦学性能的影响，特别是为了深入了解石墨烯如何减少摩擦的机制。摩擦和磨损率。使用 3D 激光测量显微镜和 X 射线光电子能谱对磨损的凹槽形貌和表面成分进行了详细表征。在 UMT-TriboLab 上的摩擦学测试结果表明，光滑的初始表面更有可能在水润滑下获得较低的摩擦系数和磨损率。SiC 和 Si3N4 陶瓷的合适初始表面粗糙度约为 Ra 10 nm，在酒精或石墨烯水溶液中会更低。大负载不会使 Si3N4 球在 SiC 盘上滑动的摩擦学行为恶化，并且会降低摩擦系数和磨损率。在干摩擦、干石墨烯润滑、水润滑、石墨烯溶液润滑和自主研发的石墨烯润滑五种润滑状态中，自主研发的石墨烯润滑剂可以表现出0.009的超低摩擦系数和0.009的超低磨损率。 1.69 × 10−7 mm3/N·m。石墨烯涂层陶瓷表面优异的摩擦学性能有助于制备的润滑剂有效降低摩擦系数。此外，石墨烯薄膜可以保护 SiC 在摩擦活化作用下不被水氧化，从而在低摩擦条件下实现超低磨损率。酒精改善了自主研发的石墨烯润滑剂的摩擦学性能，主要是因为石墨烯和乙醇之间具有良好的润湿性。自主研发的石墨烯润滑剂可应用于水润滑陶瓷轴承和电动精密主轴。