Controllable Preparation And Research On Wear Mechanism Of Resin Matrix Carbon Brush Modified By Sulfonated Graphene

As an important part of the motor rectifier,resin matrix carbon brush(RMCB)materials are influenced by the mechanical wear,electrical wear and chemical corrosion when the motor is operated at high speed.Compared with conventional friction and wear,this mechanical/electrical coupling system works in particaular harsh condition.Most of the existing researches on the carbon brush focus on the usage of traditional modifiers on the filler or the binder as the main modification,or the improvement on the carbon brush preparation process.But there are few researches focusing on the usage of new nano-materials and interface design idea to prepare carbon brush materials with good performance,and exploring the impact of the new carbon nano-materials on the traditional carbon industry through the simplest ratio of raw materials.In this paper,aiming at solving the defects of the existing resin-based carbon brush,difficult to be combined with anti-broken,anti-wear and anti-arc matching,we regard the connections among "functional modification-current-carrying wear properties-force,electrical properties-microstructure characterization-material mechanism analysis" as the research idea,and regard the interfacial mechanism and the mechanism of friction film formation as the research object.In this paper,a new type of low-dimensional carbon nano-materialsl--sulfonated graphene(SG),is used as the interface modifier,and the effect of SG on different resin-based carbon brushes and the effect of different SG contents on the current-carrying wear properties of the resin-based carbon brush materials are studied.as a result,the effect of SG on the mechanism of stress relaxation in the interface of resin-based carbon brush material and formation mechanism of friction film on carbon brush surface are elucidated.The main conclusions are as follows:(1)The static and dynamic properties of phenolic resin-based carbon brush materials before and after modification of SG were studied,and the microstructures of them were characterizated.The results shows that the flake graphite powder modified by SG presents large slice distribution,the flexural strength and hore hardness of the resin-based carbon brush after the modification are improved by 80.6%and 49.5%,respectively,and the wear rate is reduced by 68.7%,as the same as M839,compared with those of the unmodified carbon brush.Scanning electron microscopy(SEM)reveals that the morphology feature of carbon brush,modified by SG,surface presents the status of "interconnected adhesion".(2)The epoxy resin was used as the matrix material of carbon brush,and the effect of SG on the comprehensive properties of epoxy resin-based carbon brush was studied.The result shows that its mechanical properties and the current-carrying wear properties are both significantly improved when the epoxy resin content is 25wt%.On the basis of that,the effect of different SG content on the properties of epoxy resin-based carbon brush was studied.The result shows that,compared with unmodified carbon brush,the flexural strength is 18.9%higher and the wear rate is 40.9%lower,respectively,and spark level is also basically maintained at 11/4 level when the SG content is lwt%.(3)The effect of SG on the properties of resin-based carbon brush material was deeply analyzed,the modification mechanism of SG for the interface of resin-based composite and the absorption and dispersion mechanism of SG on the internal stress under external load were deduced.Also,the effect of SG on the dynamic formation mechanism of the friction film of carbon brush surface and the synergistic mechanism with the graphite powder during the current-carrying process were emphasizely studied.