Study On Current-Carrying Lubrication Of Several Modified Carbon Composite Greases

Due to their unique structure,graphene and carbon nanotubes have ultra-high strength,great toughness,and excellent electrical and thermal conductivity.However,due to the large specific surface area of graphene and the large aspect ratio of carbon nanotubes,graphene And carbon nanotubes are easy to take the form of agglomeration,it is difficult to disperse in the matrix,so it is very important to modify them.In this paper,under the action of mechanical grinding and shearing,non-covalent modification of graphene and carbon nanotubes with ionic liquids was carried out to study the current-carrying tribological properties of the modified graphene and carbon nanotubes as lubricant additives.The research results are as follows:(1)Dissolve lithium salt into PAG(50-HB-660)by in-situ method to prepare ionic liquid,use polyurea grease(PAO)as base grease,modified graphene and modified carbon nanotubes etc.Conductive additives prepared electric compound grease,tested its physical and chemical properties,and found that the prepared grease has good thermal stability and corrosion resistance to meet the needs of practical applications.(2)The distribution of graphene in the base grease was simulated by Monte Carlo algorithm,and the conductive mechanism of the grease was analyzed in combination with the theory.It was found that with the increase of graphene concentration,the conductive ability of the grease gradually increased.Under the Cu-Cu friction pair,the dynamic conductivity and current-carrying tribological properties under the boundary lubrication condition of conductive grease were explored.It was found that the grease prepared by the modified graphene and carbon nanotubes was at a low load(5N),High load(10N),or under current-carrying or non-current-carrying conditions,all show more excellent anti-friction and anti-wear performance and electrical conductivity than the grease prepared by unmodified graphene and carbon nanotubes.The reason is that the modification of the ionic liquid improves the dispersibility of graphene and carbon nanotubes in the grease,thereby improving the performance of the grease.Comparing the grease prepared by graphene and carbon nanotubes,it is found that the grease prepared by modified graphene and modified carbon nanotubes under low load(5N)has little difference in friction and wear resistance,and under high load(10N)Carbon nanotube grease has better anti-friction and anti-wear properties.(3)The distribution of temperature field and shear stress in the process of friction is simulated by ANSYS software.It is found that the highest temperature and maximum stress in the process of friction are generated in the center of friction.The generation of friction heat can transfer and cause the change of surrounding temperature field and stress distribution.