基于分子动力学模拟的石墨烯/聚四氟乙烯复合材料两级抗磨机制研究

doi:10.3901/JME.2022.13.175

摘要/Abstract

摘要： 为研究超耐磨石墨烯/聚四氟乙烯复合材料的抗磨机制，采用大气环境/干燥氩气摩擦试验、纳米压痕测试、黏附力测试方法研究表面力学性能对复合材料磨损行为的影响，通过分子动力学模拟研究摩擦界面中的分子相互作用和复合材料磨损行为的关联。实验结果显示，在大气环境中，石墨烯填料的使用降低了聚四氟乙烯99.8%的磨损；而在干燥氩气中，复合材料的磨损率比大气环境中提高了约一个数量级。纳米压痕测试结果显示复合材料在大气环境下磨损后的表面硬度、弹性模量和黏附力比干燥氩气环境下的磨损表面分别高43.4%、47.4%和68.5%。水滴接触角和红外光谱测量结果显示大气环境磨损后的复合材料表面相比原始表面具有更强的极性相互作用。分子动力学模拟显示，强的极性相互作用提升了复合材料的力学性能和固体润滑膜的吸附性，它们共同作用降低复合材料磨损。研究结果揭示出两级减磨机制对石墨烯/聚四氟乙烯复合材料的低磨损行为的重要性，这对设计新型固体自润滑界面具有指导作用。

关键词: 摩擦, 磨损, 显微硬度, 分子动力学, 石墨烯

Abstract: To study the mechanisms of wear of graphene oxide-polytetrafluoroethylene (GR/PTFE) composites, the effects of surface mechanical properties and molecular interactions on the wear behaviour of composite are investigated by using environmental wear tests, nanoindentations, and adhesion force measurements. The mechanism of wear of composite is further studied by using molecular dynamics simulation for the frictional interface. Experimental results showed that the use of graphene filler reduces the wear of PTFE by 99.8% in the atmospheric environment. In dry argon, the wear rate of the composites is an order of magnitude higher than that in atmospheric environment. Nanoindentation tests suggested that the surface hardness, elastic modulus and adhesion force of the composite after wear in atmospheric environment are 43.4%, 47.4% and 68.5% higher than those of the worn surface in dry argon environment, respectively. The measurements of water contact angle and infrared spectroscopy showed that the composite surface after wear in atmospheric environment has stronger polar interaction than the original surface. Molecular dynamics simulations suggested that stronger polar interactions improved the mechanical properties of the composites and the adsorption of transfer films, and they synergistically reduce the wear of the composites.

Key words: friction, wear, microhardness, molecular dynamics, graphene

中图分类号:

TH117

孙魏, 宋庆瑞, 刘焜, 刘小君, 叶家鑫. 基于分子动力学模拟的石墨烯/聚四氟乙烯复合材料两级抗磨机制研究[J]. 机械工程学报, 2022, 58(13): 175-184.

SUN Wei, SONG Qingrui, LIU Kun, LIU Xiaojun, YE Jiaxin. Two-level Wear Reduction Mechanism and Molecular Dynamics Simulation for GR/PTFE Composites[J]. Journal of Mechanical Engineering, 2022, 58(13): 175-184.

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