Dispersion Stability And Tribological Properties Of Additives Introduced By Outfield Ball Milling In Oil

In industrial production,lubricants are often used to reduce the friction and wear of the machine,to prolong the service life of the machine and reduce the scrap rate.With the rapid development of science and technology,the existing lubricants have been gradually unable to meet the current needs of production and life.It has been found that the introduction of additives can further improve the performance of the lubricant and meet its strict requirements under high temperature,high speed,high load and other working conditions.Therefore,the introduction of additives into lubricants is the most important and effective means to improve the performance of lubricants.However,at the present stage,researchers mainly focus on the selection and preparation of high-performance additives,and pay more attention to the optimum content of additives and wear-reducing mechanism.However,low attention is paid to the method of introducing additives into lubricating oil,so the existing methods are difficult to form long-term and stable dispersion of additives in lubricants,and the dispersion degree of additives in lubricants will have a great impact on the performance of lubricants.In this work,graphene and molybdenum disulfide were modified by organic molecules through ultrasound and microwave ball milling(UMBM)equipment made in our laboratory to make them have certain lipophilicity.Then the modified additive was introduced into the base oil PAO6 by UMBM equipment.The graphene and molybdenum disulfide before and after modification were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),transmission electron microscope(TEM)and Fourier transform infrared spectroscopy(FT-IR).The dispersion stability of additives in oil was detected by Ultraviolet visible spectrophotometer(UV-VIS)and Zeta potentiometer,and the effects of different additives and UMBM treatment on dispersion were studied.The surface modification effect and dispersion mechanism were discussed respectively.After that,the tribological properties of lubricating oil were tested by a four-ball friction and wear tester,and the effects of different content and ratio of additives on the tribological properties of lubricating oil were studied.And the effect of UMBM treatment on the tribological properties of additives in lubricating oil were studied.By magnifying and observing the friction surface,the element analysis of the friction surface was carried out by means of Raman spectrum,energy dispersive X-ray spectrometer(EDS)and X-ray photoelectron spectrometer(XPS).After that,the friction-reducing and anti-wear mechanisms of the two additives were discussed.The results show that the introduction of graphene and molybdenum disulfide into lubricating oil can greatly enhance the antifriction and antiwear performance of lubricating oil,and there is a synergistic effect between graphene and molybdenum disulfide,and the effect is much better than that of single additive.The anti-friction and anti-wear mechanism of additives is mainly deposited and adsorbed on the friction surface to form a protective lubricating film,which reacts with the friction surface to form substances conducive to friction or the wear marks filled on the friction surface play a repair role.At the same time,UMBM treatment is an effective means to introduce additives into lubricating oil.UMBM treatment can effectively improve the dispersion of additives in lubricating oil,improve the film-forming efficiency of lubrication protective film,and thus play a positive role in the friction performance of additives.