氧化石墨烯和纳米SiO_(2)增强PTFE复合材料的摩擦磨损行为

Friction and Wear Behavior of Graphene Oxide and Nano-SiO_(2)Reinforced PTFE Composites

为研究具有层状结构和球状结构的纳米填料之间的相互作用对聚四氟乙烯(PTFE)复合材料摩擦磨损行为的影响,采用冷冻干燥超声共混-冷压-热烧结法制备纳米二氧化硅(nano-SiO_(2))和氧化石墨烯(GO)填充改性PTFE复合材料。利用LSM-2R往复式摩擦磨损试验机测试干摩擦条件下nano-SiO_(2)和GO复配改性PTFE复合材料的摩擦学性能,采用MicroXAM-800非接触式三维表面轮廓仪、扫描电子显微镜(SEM)和能谱仪(EDS)分析表征转移膜形貌、元素分布和磨痕表面三维形貌,从微观层面揭示nano-SiO_(2)和GO的减摩机制。结果表明:单独填充nano-SiO_(2)与GO均可改善PTFE复合材料的摩擦学特性,其中在较低添加量下,GO在提高PTFE耐磨性方面明显优于nano-SiO_(2);GO和nano-SiO_(2)复配填充时存在协同效应,与单一填充相比进一步改善了复合材料的摩擦学性能;相比于纯PTFE,3%nano-SiO_(2)/0.5%GO/PTFE复合材料的磨损率降低60.36%。机制分析表明,协同作用和均匀连续转移膜的形成是nano-SiO_(2)和GO增强PTFE复合材料性能优异的主要原因。

In order to study the effect of the interaction between nano-fillers with layered and spherical structures on the friction and wear behavior of polytetrafluoroethylene composites,nano-silica(nano-SiO_(2))and graphene oxide(GO)filled polytetrafluoroethylene(PTFE)composites were prepared by freeze-drying-ultrasonic blending-cold pressing-hot sintering method.The tribological properties of the nano-SiO_(2)and GO compound-modified PTFE composites were tested under dry friction conditions using the LSM-2R reciprocating friction and wear tester,and the transfer film morphology,elements distribution and three-dimensional morphology on the wear track were characterized by MicroXAM-800 non-contact three-dimensional surface profiler,scanning electron microscope(SEM)and energy spectrometer(EDS).The friction reduction mechanism of nano-SiO_(2)and GO was also revealed from the microscopic level.The results show that the friction and wear properties of PTFE composites can be improved by filling nano-SiO_(2)and GO separately,and GO is significantly better than nano-SiO_(2)in improving the wear resistance of PTFE at a low additive amount.There is a synergistic effect between GO and nano-SiO_(2)when composite filling,which further improves the tribological properties of the composite material compared to a single filling.Compared to pure PTFE,the wear rate of 3%nano-SiO_(2)/0.5%GO/PTFE composite material is reduced by 60.36%.The mechanism analysis shows that the synergistic effect and the formation of uniform continuous transfer film are the main reasons for the excellent performance of nano-SiO_(2)and GO reinforced PTFE composites.