Study On The Tribological Properties Of Nano Copper And Graphene Lubricating Oil Compound Additives

Ship mechanical equipments often run in high temperature and pressure conditions,resulting in serious friction and wear,therefore,good lubrication conditions are essential.With the development of nano materials,nanoparticles as lubricant additives have a wide range of applications.Each kind of materials has the different characteristic,the compound nanometer lubricating oil additive can take full advantage of the performance of various nano particles to reduce friction and wear.In this paper,nano Cu particles and grapheme as the lubricating oil additive were selected to prove their tribological properties by friction and wear test,which provided the theoretical basis for practical research and application The following studies were conducted:1 The nano Cu particles were prepared by liquid phase reduction two-step method,and grapheme was prepared by modified Hummers method.The prepared particles were characterized by XRD,and the composition of the particles was confirmed by standard PDF cards.The size of the particles was measured by nano laser particle size analyzer,the results showed that the particles were in accordance with the experimental requirements.2 According to the agglomeration and dispersion mechanism of nano particles,oleic acid was used to modify the nano Cu particles,and the graphene was modified with octadecylamine.Unmodified and modified particles by centrifugal sedimentation experiment and absorbance experiment,the experiments show that the oleic acid modified nano Cu particles and octadecylamine modified grapheme can be uniformly and stably dispersed in the lubricating oil.3 The nano Cu particles and grapheme were prepared in a single dose and compound form into different mass fraction of lubricating oil,the four-ball long grinding orthogonal experiment was carried out under the steady state.The friction coefficient and wear scar diameter of each experimental group determine the additive effect,the compound mass fraction of 0.05%,the quality ratio WtCu%:WtGr%=20%:80%experimental group is the best.Compared the blank group,the friction coefficient was reduced by 31.34%,and the wear spot diameter was reduced by 22.31%.4 The optimal group was subjected to reciprocating friction and wear test under complex conditions which the temperature and load changed,by comparing the wear and friction coefficient,scanning electron microscopy(SEM)observation of the friction surface,energy dispersive spectroscopy(EDS)detection type and content of elements,the results showed that the amount of wear in the experimental group with the addition of the optimal compound additive was reduced by more than 8%,the surface of the specimen is more flat,new element Cu was detected,and the content of C element increased,the tribological properties of additives were further investigated.