轴承滚珠表面二维异质纳米复合涂层制备及固体超润滑研究  

Preparation and Solid Superlubricity of Two-dimensional Nanocomposite Coating on Bearing Ball Surfaces

作　　者：杨兴 王永富 张俊彦[1] 张斌[1] 李瑞云 YANG Xing;WANG Yongfu;ZHANG Junyan;ZHANG Bin;LI Ruiyun(State Key Laboratory of Solid Lubrication,Lanzhou Institute of Chemical Physics,Chinese Academy of Science,Lanzhou 730000,China;State Key Laboratory of Tribology in Advanced Equipment,Tsinghua University,Beijing 100084,China)

机构地区：[1]中国科学院兰州化学物理研究所固体润滑国家重点实验室,兰州730000 [2]清华大学高端装备界面科学与技术全国重点实验室,北京100084

出　　处：《表面技术》2024年第21期14-22,共9页Surface Technology

基　　金：国家重点研发计划(2023YFB4603601)。

摘　　要：目的针对工程规模生产的二维异质纳米粉体因强边缘效应和摩擦导致的复杂接触重构等问题,提出一种利用二维异质纳米粉体实现宏观超润滑的策略,分析摩擦界面二维材料的复杂接触重构现象,推动二维异质纳米粉体宏观超润滑的工程应用。方法通过掺入石墨烯边缘氧,削弱二维纳米材料边缘钉扎效应,促进二维异质纳米粉体发生异质结转化,并控制同质结-异质结转化,实现载荷和速度可调的宏观超润滑。结果相较于无氧掺入体系,石墨烯边缘氧可以诱导二维异质纳米片(石墨烯、MoS2)在轴承滚珠表面的分层组装和充分混合,制备出大量纳米尺度同质结和异质结共存的复合涂层。当与无定形碳薄膜组成摩擦副时,二维纳米复合涂层实现了载荷和速度可调的宏观超润滑(摩擦因数低至0.007)。分子动力学模拟结果显示,石墨烯边缘原子的活性较高,容易发生层间化学作用和边缘钉扎效应,而边缘氧钝化后可以有效削弱边缘钉扎效应。结论通过引入石墨烯边缘氧钝化技术,可以有效削弱边缘钉扎效应,促进二维异质纳米粉体到异质结的转化,调控同质结-异质结的转化,实现宏观超润滑,这为结构超滑的规模放大和工程应用提供了重要的技术途径。Structural superlubricity has been limited in nanoscale and microscale,which needs more efforts to achieve macroscale superlubricity.At present,two-dimensional nanopowders produced on an engineering scale have attracted more and more attentions.However,it is difficult to achieve macroscopic superlubricity as their single crystal state due to strong edge effects and friction-induced complex contact restructuration.Here,a strategy based on ball milling method under humidity environment was proposed to incorporate graphene edge oxygen for weakening the edge pinning effect of two-dimensional nanoflakes, to promote the conversion of two-dimensional nanopowder to heterojunction and the macroscale superlubricity at wide ranges of load and speed. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) characterizations were used to compare the structures and compositions of two types of samples obtained under vacuum and humidity environments. The results showed that about 10% oxygen could be doped in the graphene edge to form C-O-C bonds during the humidity ball milling process, which weakened the edge pinning effect and retained the smooth interlayer slipping between two-dimensional materials. This finally induced the layered assembly and good mixing of two-dimensional nanosheets on the bearing ball surface, promoting the formation of the coexistent structure containing countless heterojunctions and homojunctions. As a contrast, the sample obtained under vacuum environment showed a poor mixing of graphene and MoS2. As expected, the humidity-milling sample exhibited a lower frictional coefficient (0.007) and wear under Ar environment than the vacuum-milling sample when paired with the amorphous carbon film. Combining the wear scar and track results of the ball milling samples, the friction behavior of humidity-milling sample was contributed by the contact restructuration of heterojunctions and

关 键 词：二维纳米粉体 结构超滑 石墨烯 二硫化钼 异质结 涂层 轴承滚珠 

分 类 号：TH117[机械工程—机械设计及理论]