Study On Tribological Behavior Of Polymer-metal Interfacial Nanometer Tribofilm Membrane Under Oil Lubrication

With the rapid development of modern industry,many movement mechanisms are in service under increasingly severe environment.Boundary lubrication and even dry friction often occur,which poses severe challenges to the service life and reliability of movement mechanisms.Due to its characteristics of self-lubrication,high chemical stability and designability,polymer materials are playing an increasingly important role in tribological design of motion mechanism of modern automobile and high-end equipment.However,the bearing capacity of polymer matrix materials is often poor and the wear resistance under harsh conditions is insufficient.It is found that the addition of nanoparticles into the polymer matrix can promote the formation of uniform transfer film at the interface of the friction pair,which can significantly reduce the friction and wear of the polymer composite material,but the research on the friction mechanism is lacking.In this work,the influence of microstructure and load velocity on tribological properties of EP composites under PAO lubrication conditions was investigated,and the mechanism of interface physicochemical interaction and transfer membrane growth was also discussed.Centered "in-depth study transfer membrane formation mechanismanalysis transfer membrane structure-design self-lubricating material" of the main line,in view of the PAO lubricating medium,in the condition of boundary and mixed lubrication,analyzed the different physical and chemical properties of nanoparticles and new graphene based materials-Graphene Quantum Dots(N-GQDs)on the influence law of conventional polymer material tribology performance quantitative characterization of the formation in oil lubrication medium transfer membrane micro/nano structure.The main research contents are as follows:1.In PAO lubrication medium,the effects of different types of nanoparticles on tribological properties of epoxy resin composites were studied.The mechanism of action of nanoparticles on tribological behavior of polymer composites under harsh boundary and mixed lubrication conditions was investigated.The effects of different physicochemical properties of nanoparticles on the formation of transfer membranesand nanostructures were investigated.The results show that under the condition of high load and low speed,the pure epoxy is easy to bond with the metal,which leads to the significant increase of the friction coefficient and wear rate of the composite material.The addition of ceramic Al2O3 nanoparticles is more likely to promote the formation of uniform transfer membrane and significantly reduce friction and wear.Also under high load low speed,the other kinds of nanoparticles is added in the epoxy matrix can also promote the form a layer on the surface of metal dual transfer film,such as adding high hardness of Si C and nano Zr O2 particles released into the contact friction pair in the process of friction interface can effectively remove the oxide layer on the surface of the metal to further improve the tribological performance.The analysis shows that the high performance transfer film formed at the interface of the friction pair not only eases the direct scraping of the material surface,but also improves the bearing capacity of the friction interface,thus improving the tribological properties of the EP nanocomposite.2.A new type of zero-dimensional structure nitrogen-doped graphene quantum dot,namely N-GQDs,was successfully synthesized and prepared.The effect of N-GQDs and nano-Al2O3 particles and their coupling on tribological behavior of epoxy resin under PAO lubrication was studied.The formation,structure and influence mechanism of N-GQDs,ceramic nanoparticles and coupling on solid transfer membrane at interface of friction pair were studied.The results show that the friction coefficients decrease with the addition of N-GQDs with different mass fractions in EP resin.In addition,the Al2O3/N-GQDs coupled to improve the friction performance has significant synergistic effect of epoxy resin,improve the overall tribological performance of friction pair interface,and the dual form the surface of the solid metal transfer membrane greatly improves the transfer of the membrane shear properties,in addition to all this solid transfer membrane sinter nano-Al2O3 particles in the process of friction for most of the load,reducing the wear rate of friction materials.