The Research On Tribological Properties Of Graphene

Lubrication is the important method to decrease abrasion,save energy,improve production efficiency and reliability.In the atmosphere of promoting energy saving and sustainable development sociality hardly,to explore the lubricant which is environmentally friendly and has more excellent performance is necessary.Allotropes of carbon have excellent lubrication performance generally.They aren't harmful to environment and have a great store in our country,so it provides a sufficient substantial basis to develop and apply graphite-like lubricant.Since graphene has been discovered,graphene get into people's view quickly by its unusual characters at optics,electricity,thermotics and mechanics field.In this paper,graphene has been studied deeply through the points of tribology.The system of graphite-like lubricant has been perfected and it provides the theoretical foundation for the applying of graphene lubricant in industry.The tribological properties of graphene have been studied in three normal ways.Firstly,graphene was putted into the friction surface,and HT-1000 high temperature friction testing machine was used to test the friction performance of graphene at different load,rate and temperature,then orthogonal test was adopted to analyze more.Secondly,graphene-epoxy resin composite has been prepared.The affection about different additive amount to friction performance of composite has been studied.Thirdly,graphene was mixed into 500SN basis oil,and then the change of carrying capacity of the oil was tested.Through the SEM and EDS analysis,the lubrication mechanism of graphene in three conditions above were discussed deeply.The main results of this study are as follows:Graphene has an excellent lubrication function.When it is used as solid lubricant between the friction surfaces,it could decrease the friction coefficient and wear rate effectively,and its lubrication capacity is influenced by temperature and load obviously.Graphene has a weak adhesive force to metal surface,so the lifetime of lubricant film is short.Graphene can fill the pit and scratch in friction surface,reducing roughness,and it can lead to carburization,increase the hardness of surface.But graphene can also scratch the friction surface.Abrasive wear is the main wear type.Moderate graphene can improve the abrasive resistance of epoxy resin.In the normal temperature,when the additive amount of graphene is 0.25wt%,the friction coefficient and wear rate of graphene-epoxy resin composite reach minimum.Superfluous graphene would increase the friction coefficient and wear rate.The best additive amount would ascend when temperature rise.Graphene enhance the strength of epoxy resin,and the graphene that fall off would play a lubrication action.But superfluous graphene would break the cross-linked network,causing stress concentration and decreasing strength.The main wear type is adhesive wear,then abrasive wear accompanies.In oil additive side,graphene can improve the carrying capacity of oil prominently.The best additive amount is 0.04wt%,then the PB of oil increases by 102.4%,and PD increases by 15.9%,friction coefficient and wear rate decrease,too.Moderate graphene can get into the friction surface and fill the scratch,and protect the surfaces.But superfluous graphene would break the integrity of oil film,aggravating wear.Abrasive wear is the main wear type.