| Since water-based lubrication has obvious advantages such as low pollution and low energy consumption,it has gradually replaced traditional oil-based lubrication and become the best choice for industrial lubrication systems.However,the main reasons for limiting the development of water-based lubrication technology were the insufficient anti-friction and anti-wear properties of traditional additives and the poor film-forming ability of water-based lubrication.The subject was mainly aimed at the problem of insufficient anti-friction and anti-wear performance of additives.The liquid graphite exfoliation theory was used to prepare exfoliated graphite to prepare aqueous dispersion of graphene.The mechanism of exfoliation and dispersion of graphene in pure water was studied.In the lubrication theory,we explored the effect of graphene as a water-based lubricating nano-additive on its anti-friction and anti-wear properties.On the one hand,the topic provides a certain idea for the realization of large-scale preparation of graphene in industrial applications,on the other hand,it does a certain amount of exploration work for the research direction of water-based lubrication applications at nanoscale.The main research contents of this article are as follows:1.Characterize the dispersion stability and number of layers of graphene in the dispersion through the light transmittance method,volume sedimentation method,Zeta potential detection and SEM,AFM,Raman.The experiment proves: 0.1wt%(sodium dodecylbenzene sulfonate(SDBS): melamine(Melamine)= 1:1),0.5wt%SDBS,0.3wt% octadecyltrimethylammonium(STAC)chloride system medium graphene has remarkable exfoliation effect and perfect dispersion stability.Among them,the average number of graphene layers in the 0.1wt%(SDBS: Melamine = 1:1)system was about 21 layers,and the graphene has not settled for 22 days at 25±2.5℃;the graphene in the 0.3wt% STAC system The average number of layers was about 14 layers,and the graphene has not settled for 13 days at 25±2.5℃.The dispersion system exfoliates as few as 8 layers of graphene nanosheets.2.According to Amonton’s law,the lateral force calibration theory was calculated used the wedge method lateral force calibration and the rapid calibration theoretical model,and the lateral force of the atomic force microscope(AFM)friction force in the subject was calibrated.The lateral force calibration coefficient meets the experiment Precision requirements.3.Choose 5 different graphene aqueous dispersions with different dispersibility:0.1wt%(SDBS: Melamine=1:1),0.5wt% SDBS,0.3wt% CTAB,0.5wt% SDS,0.5wt% PVP system(which Dispersion decreases in turn),formulated into graphene water-based lubricating fluid,AFM friction test was performed on dry friction,pure water lubricating fluid and graphene water-based lubricating fluid at nanoscale.The results prove that: compared with dry friction and pure water lubricating fluid,in the0.1wt%(SDBS: Melamine=1:1)lubricating fluid with the best dispersibility,graphene nanosheets evenly adhere to the tip of the AFM probe.It avoids the blunt phenomenon of the probe due to wear during scanning,which proves that graphene has a good anti-friction and anti-wear effect in the nano-scale friction theory.Further experiments prove that the lubricating performance is the best when the dispersant and graphene were 0.2 in 0.1wt%(SDBS: Melamine=1:1)lubricating fluid.It was proved that the water-based lubricating effect of graphene was positively related to its dispersion stability in the research of nano-scale water-based lubricating applications. |
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