Tribological Properties Of Ionic Liquid Modified Carbon Nanoparticles As Grease Additives

Electrical contact phenomenon exists widely in all kinds of power occasions,and the performance of electrical contact is the main factor affecting its safe operation.As a result,it usually needs to be coated on the parts with poor electrical conductivity and easy contact.In order to prepare grease with excellent tribological properties and good conductivity,nano carbon materials with unique self-lubricating and good conductivity were selected as grease additives,but the compatibility between Nano carbon materials and base grease was poor.Therefore,several nano carbon materials modified by ionic liquid were prepared and used as grease additives to investigate the properties of grease Physical and chemical properties,current carrying and non current carrying tribological properties.The main research contents and results are as follows:(1)Using ionic liquids with different carbon chain lengths as modifiers,carbon nanotubes modified by ionic liquids were prepared by mechanical grinding method,and used as lubricating grease additives.The tribological properties and electrical conductivity of lubricating grease with different additive contents were investigated.It is found that the friction reducing and anti-wear effect of 0.15%[C14MIM][NTF2]+MWCNTs grease is better when the load is 125N and the load is 50N,75N,100N and 125N;When the load is 10N,the voltage is 500mV and 1500mV,0.15%[EMIM][NTF2]+MWCNTs grease has the best antifriction,anti-wear and electrical conductivity.The surface analysis of current carrying wear marks shows that there are carbon nanotube physical deposition film and tribochemical reaction film on the surface of wear marks.(2)Graphene,Graphite and Silver powder were used as composite Lithium-based grease additives to investigate the effects of different additives on the tribological and electrical properties of grease.The friction experiment shows that the friction reducing and anti-wear effect of 0.2%Graphene grease is the best when the load is set at 25N,50N,100N and 150N and the load is 50N and 150N;Under the condition of 15N load and 1500mV voltage,the tribological properties and electrical conductivity of 0.2%graphene grease are the best.The main reason is due to the unique microstructure of graphene and the lubricating protective film formed on the friction surface.(3)Ionic liquid modified graphene and ionic liquid modified graphite were used as composite lithium-based grease additives to investigate the effects of different additives on the tribological properties and electrical conductivity of grease.The friction experiment shows that the friction reducing and anti-wear performance of 0.3%[C14MIM][NTF2]+Graphene grease is better under the set load of 25N,50N,100N and 150N and the load of 150N;The results show that the contact resistance,friction coefficient and wear scar width of 0.3%[EMIM][NTF2]+Graphene grease are the smallest when the load is 15N,the voltage is 500mv and 1500mv.0.3%[EMIM][NTF2]+Graphene grease has better wear scar surface quality,which is related to the boundary lubrication film formed by physical adsorption film and chemical reaction film.(4)ANSYS finite element analysis is used to simulate the stress,strain,voltage,current and temperature of copper friction pair under current carrying condition.The results show that when the load is 25N and the current is 1.5A,the stress and strain,current density,calorific value and temperature in the contact area are the highest.