Preparation Of The Metal Nanoparticles/graphene As Lubricating Additives By Plasma Assisted Ball Milling

Frictional wear is inevitable in the operation of ship power equipment,and lubricating oil which contains appropriate additive can reduce the friction and resist the wear.However,the metal nanoparticles/graphene as lubricating oil additive can not only reduce the friction and resist the wear,but also repair the surface of frictional parts.Based on the above,this paper mainly focuses on the research of“preparation of the metal nanoparticles/graphene by plasma assisted ball milling”.SET,TEM,XRD,Raman,FT-IR and other experimental methods were used to study the effect mechanism of plasma assisted ball milling time,amount of added Cu powder and Cu powder and Sn powder with different Moh's hardness on the preparation of the metal nanoparticles/graphene separately.The tribological performance of PM5h-0.05Cu/Gns and PM10h-0.05Cu/Gns composite materials used as lubricating oil additives were also tested.Six groups of Cu/Gns composite materials were prepared through PM5h and PM10h,using Cu powder and expanded graphite with molar ratios of 0.05:1,0.2:1 and 0.8:1 as raw material,oleic acid as modifier respectively.The test results showed that the expanded graphite was smashed and stripped into graphene.Under the condition of the mole ratio unchanged,the layer number of the graphene gradually decreased and the degree of ordering is gradually weakened with the increasing of ball milling time.With the enhancement of mole ratio,expanded graphite strip speeds up,simultaneously intensifying the disorder of graphene.Under the effect of unique“smashing-thermal explosion-condensation”mechanism of plasma assisted ball milling,the Cu powder was gradually smashed,loaded on graphene and formed a stable spherical Cu/Gns composite.With the extension of ball milling time from 5 hours to 10 hours,the grain size of Cu powder decreased gradually and the lattice distortion increased gradually.Different from other components,when Cu powder and the molar ratio of expanded graphite was 0.05:1,irregular form of Gns/Cu composite materials appears after 5 hours ball milling time.Two groups of Sn/Gns composite materials were prepared through PM5h and PM10h,using Sn powder and expanded graphite with a molar ratio of 0.8:1 as raw material,oleic acid as modifier.The test revealed that the stripping effect of Sn on expanded graphite was mainly due to the splash impact of the“thermal explosion”of Sn powder because the Moh's hardness of Sn powder is low and the“thermal explosion”is very strong.As PM5h added to PM10h,the occurrence of re-crystallization and growth of Sn powder made the grain size of Sn powder decreased first and then increased,while the lattice distortion increased first and then decreased.Compared with Cu powder,the grinding efficiency of Sn powder declined and Sn/Gns graphene thickness is higher than that of the Cu/Gns in the same ball milling time.Through FT-IR test,it was found that after PM10h,a large number of long alkanes contain-CH₂-were grafted onto the surface of Cu/Gns and Sn/Gns samples,changing samples into non-polar structures and making it form oil-wet and hydrophobic properties.This effectively prevented the agglomeration of the powder and greatly enhanced the dispersion stability of the sample in the lubricant,which didn't find in the sample of the one after PM5h.Compared with base oil lubrication,when using PM5h-R3209 compound lubricating oil,grinding spot diameter reduced by 7.6%,the friction coefficient decreased by 0.6%and the standard deviation was 13.4%lower than before,the stability of the sliding friction also being improved in some extent.When using PM10h-R3209 compound lubricating oil,grinding spot diameter reduced by 12.3%,the friction coefficient decreased by 6.4%and the standard deviation was 62.3%lower than before,the stability of the sliding friction being overwhelmingly improved.