The Triboligical Effect Of Graphene And Carbon Nanotubes Materials As Additives To Lubricant

Along with the development of society and the improvement of technology,transportation,chemical industry,mechanical engineering and other sorts of industry are developing rapidly.However,following a large amount of energy consumption,heat loss and material loss caused by friction and wear have slow down the development of the industry.The method to improve the utilization of energy has become a problem to be solved.In order to alleviate the energy loss problem caused by friction and wear,lubricant technology arose at the historic moment.At the same time,in order to make the lubricant have better antifriction performance,people have developed different kinds of additives.And the emerging carbon nanomaterials additives have caused the extensive attention from all circles of the society.In this thesis,first of all,we studied the morphology characterization and dispersity of graphene and graphene oxide.The outcome proved that graphene has good lipophilicity and adding oleic acid makes graphene to be dispersed in lubricating oil stably.At the same time,graphene oxide(GO)has good hydrophilicity,which can be evenly dispersed in the water and remained stably.After that,we prepared and did characterization of the carboxyl carbon nanotubes(CNTs-COOH),super short carbon nanotubes(SS-CNTs)with different scales,partialy exfoliated carbon nanotubes(Px-CNTs)and graphene oxide nanoribbons(GONRs).The derivative of the carbon nanotubes have good hydrophilicity,which can dispersed in water stably.At the same time,this article explored the tribological performance of the graphene and carbon nanotube materials as oil lubricant additives.After preparation a series of concentrations of lubricating oil with graphene,we did friction and friction coefficient test by the four-ball tester,the results showed that the moderate concentration of graphene could make good anti-friction effect,and the best adding quantity is 0.03 mg/m L.When the concentation of graphene is 0.03 mg/m L,the coefficient reduced 25.6% compared to the average friction coefficient of the pure base oil.However,ramification of carbon nanotubes,including CNTs-COOH,SS-CNTs,Px-CNTs and GONRs were difficult to be disperse into the lubricating oil.Also,we reduced Px-CNTs to increase the lipophilicity,but this reduction is not completely.Oxygen containing functional groups can not be totally eliminated,which lead to the reduced Px-CNTs can not be evenly dispersed into lubricating oil.Finally,we explored the tribological property of graphene materials and carbon nanotube materials as water-based lubricant additives.We studied the relationship between frictional performance of SS-CNTs with different sizes and the concentration and the relationship or the load.Similarly,we explored friction performance of different exfoliated degree.At last,we prepared and tested compounded system of GO and CNTs-COOH.Results showed that the length of carbon nanotubes shorter makes the performance of anti-friction better.Px-CNTs with the structure of both nanotubs and nanoribbons has more excellent antifriction capability because of the double structure.Although the extreme pressure resistance of carbon nanotube materials is better than that of graphene materials,the ability to resist wear and tear is poor.