Study On The Tribological Behavior Of Several Nanoparticles In Lubricating Oil

As a new type of transmission mechanism,the planetary roller screw has a wide range of applications,excellent mechanical properties,and has received extensive attention from domestic and foreign scholars.In view of the tribological problems of planetary roller screws,the composition and influencing factors of friction torque are mainly studied.However,there are relatively few studies on its lubrication problems.The basic research on the tribological properties of lubricants is not systematic enough.Therefore,This paper is based on the background of the planetary roller screw,and studies the tribological properties of nano-particle lubricants.The research results can be applied not only to the planetary roller screw but also to other mechanical transmission components.As we all know,the performance and content of additives in lubricants determine the pros and cons of lubricants and play a crucial role in the operation of machinery.Therefore,finding a suitable additive,improving the performance of the additive,and determining the optimum content are of great significance to the improvement of the performance of the lubricant.In this paper,three kinds of nanomaterials with better tribological properties,such as graphene,nano ZnO and nano TiO₂,were selected,and the tribological experiments were designed according to the operating conditions of the planetary roller screw.A systematic study was performed on the tribological properties of graphene.A 500 ns mineral oil was used as the base oil to prepare graphene oil samples with different concentrations.The samples were dispersed using ultrasonic vibration.The dispersion of graphene in lubricating oil was studied.Since graphene and graphite have similar lamellar structures,nano-graphite is used as a reference to explore the effects of working conditions such as concentration,loading,and speed on the tribological properties of lubricating oils containing nanoparticles.Draw the curves of friction coefficient-concentration,friction coefficient-load,friction coefficient-speed,etc.To summarize the laws,highlight the special properties of graphene,and analyze the tribological mechanism of graphene by analyzing the wear scar on the steel ball.The surface modification methods and tribological properties of nano-ZnO and nano-TiO₂ were studied.The surface modification of nano-ZnO and nano-TiO₂ was performed using oleic acid and stearic acid,respectively.The characterization of the modified nanoparticles was performed by thermogravimetric analysis,X-ray diffraction,and Fourier infrared spectroscopy.Verify that the modifier is linked to the surface of the nanoparticles in the form of chemical bonds.Comparing the dispersion stability of nanoparticles before and after modification in oil-based lubricants,it was concluded that surface modification can improve the mutual solubility of nanoparticles and oil-based lubricants.A lot of comparative tribology experiments were carried out using a four-ball friction and wear tester to analyze the applicable conditions of the nanoparticles before and after modification under different working conditions,and through the energy spectrum analysis and scanning electron microscopy on the wear of the modified nanoparticle oil samples under the lubrication of the steel balls.The surface was analyzed,a lubrication model was proposed,and the mechanism of friction reduction and wear resistance was summarized.