银/石墨烯复合润滑添加剂对于润滑油摩擦性能的影响

Effects of Ag/RGO composites as lubricant additives on the tribological properties of lubricating oil

通过化学还原合成了银包覆石墨烯(Ag/RGO)复合添加剂,利用X射线衍射仪和扫描电镜分析了样品相成分和微观形貌,采用UMT-2摩擦磨损试验机测定了Ag/RGO复合润滑油添加剂的摩擦性能。结果表明:纳米银颗粒均匀分布在石墨烯片上,银颗粒的粒径大约200 nm。在摩擦磨损试验过程中,摩擦副与磨损表面的凹凸点直接接触,纯润滑油的润滑作用较差;在润滑油中添加Ag/RGO复合添加剂,在摩擦初始过程中,摩擦副与磨损表面也是凹凸点直接接触,随着磨损时间的增加,Ag/RGO复合添加剂在摩擦副与磨损表面之间形成一层润滑膜,阻隔摩擦副与磨损表面直接接触,产生边界润滑;另外,部分纳米银颗粒可起到微轴承作用,使得改性后的润滑油润滑性能更好。

Ag-coated graphene(Ag/RGO)composite additives were successfully synthesized by the chemical reduction method,the phase composition and microstructure of the Ag/RGO composites were characterized by X-ray diffraction(XRD)and scanning electron microscopy(SEM),respectively,and the tribological properties of the Ag/RGO composites as the lubricant additives were evaluated by UMT-2 friction and wear tester.The results show that,the Ag nanoparticles with the average size of about 200 nm are well-dispersedly attached to the RGO sheets.It is shown that,during the whole wear process,the hard micro-bulges between the counterpart and the worn surface are in physical contact using the pure lubricating oil,which leads to the poor lubricating effect.However,using the lubricating oil with Ag/RGO composite additives,the hard micro-bulges between the counterpart and the worn surface are in physical contact only at the initial wear process;as the wear time increases,a lubricating film forms due to the addition of Ag/RGO composites,which can avoid the direct contact between the worn surface and counterparts,and can further generate the boundary lubrication.Moreover,some of the silver nanoparticles in the Ag/RGO composite additives act as the micro bearings and make the lubricating effect better.