Research On Tribological Properties And Disperion Stability Of Additive IF-WS₂ In Base Oil PAO6

Traditional lubricating additives contain some poisonous chemicals such as sulfur,phosphorus,chlorine,etc.,which would release significantly toxic emissions after burning or other degradation processes,and causing environmental pollution.Therefore,it is urgent to investigate the new advanced micro-nano materials lubricating oil additives and this kind of approach has been widely believed to protect the environment and save energy.In this paper,Inorganic Fullerene Tungsten Disulfide(IF-WS₂)had been synthesized by rotating chemical vapor deposition,and the surfactants Span 80 and IF-WS₂ were uniformly dispersed together into PAO6 by ultrasonic treatment.Moreover,the effects of on the antifriction and anti-wear properties of IF-WS₂/PAO6 with different addition amount of additives,working temperature and loading were studied on four-ball friction tester(Model:MR-S10D).Besides,surfactant SDBS and Span 80were used along as compound surfactants to improve the dispersal property of IF-WS₂ in PAO6 lubricating oil.Additionally,the mechanism of SDBS improved on the antifriction and anti-wear performance of lubricating oil was further investigated.XRD,FESEM,TEM,EDS,XPS,laser confocal and other modern analytical characterizations were used to analyze the crystal structure and morphology of IF-WS₂,the surface morphology of wear scars and constitution of residual components.Explore the anti-wear mechanism of IF-WS₂ in the PAO6 oil and reveal how the SDBS improved the anti-wear property of IF-WS₂/PAO6.Also,the UV-vis spectrum,IR spectrum,viscometer and rotary oxygen bomb analysis were used to evaluate the properties of dispersion stability of additives,viscosity-temperature performance and oxidation stability.The main conclusions are as follows:(1)IF-WS₂ with irregular cage hollow structure was successfully synthesized;when the optimal addition of IF-WS₂ is 0.25%,under the load of 392 N,temperature 75?.The average friction coefficient of IF-WS₂/PAO6 decreased with 15.3%.When the test temperature is 100?,the average friction coefficient further reduced with 27%decrease,and the wear scar diameter decreases by 43.4%.Under different loads and test temperature of 100?,The average friction coefficient decreases first and then rises with load increase,and the wear scar diameter increases constantly and simultaneously.Meanwhile,in the friction process,IF-WS₂particles precipitated on the friction surface.With the synergistic effect of high temperature and pressure,IF-WS₂particles were peeled off layer by layer,and some chemically react with the friction pair matrix to form adsorption film and chemical film.Oxide layers(Fe₂O₃,Fe₃O₄,Fe(OOH),Fe₂(SO4)₃)and newly generated Fe S₂,WS₂ and WO₃ chemical films are attached to the friction surface of steel balls,hindering the direct contact of friction pairs and filling micro pits and some defects.By the iron oxide and sulfide,the wear resistance of lubricating oil is improved.Additionally,dispersant Span 80 can effectively improve the dispersion and stability of IF-WS₂in PAO6.Adding IF-WS₂ particles effectively improves the heat transfer performance and viscosity-temperature performance of lubricating oil.(2)When SDBS and Span 80 were used as compound active agents,with the increasing of SBDS addition amount,the average friction coefficient shown the gradually decreased,and the wear scar diameter first increased and then decreased.When the content of SDBS is 3%,the friction coefficient decreases by about 13%,and the wear mark diameter decreases by about 8.8%.In the process of friction,SDBS and IF-WS₂synergistic effect on wear the surface.And SDBS contributes to the dispersion of IF-WS₂ particles in PAO6.IF-WS₂ can not only fill the small pits,but also size concaves or scratches.The forming a hunk and continuous friction protective film,improving corrosive pitting,to improve the situation that IF-WS₂ cannot continuously act on the surface,and effectively enhancing the anti-wear performance of lubricating oil.Moreover,SDBS and Span 80 improve the dispersion stability of IF-WS₂with spatial mechanism and mutual reaction were demonstrated.The addition of SDBS increased the viscosity-temperature and heat transfer performance of lubricating oil in some extent,with the oxidation stability decreased by 3.4%.