外加電壓對三氧二鋁黃銅摩擦副摩擦的主動控制試驗研究Abstract:Inordertoexploretheeffectofexternalvoltageonthefrictionbetween3Al2O3andbrassfrictionpairs,anactivecontrolexperimentwascarriedout.Theexperimentalresultsshowthattheapplicationofexternalvoltagecaneffectivelyreducethefrictioncoefficientofthefrictionpair,andthereisathresholdvoltagevalueforthefrictionreductioneffect.Theinternalmechanismofthevoltageeffectonthefrictionbehaviorofthefrictionpairwasanalyzedtheoretically,anditwasfoundthatthevoltagecanchangetheelectronicstructureandchemicalpropertiesofthecontactsurface,therebyaffectingthefrictionbehaviorofthefrictionpair.

Introduction：

Withthedevelopmentofmodernindustry,frictionandwearproblemsbecomemoreandmoreimportant.Reducingfrictionandwearnotonlycansaveenergyandreducematerialloss,butalsocanimprovethedurabilityandstabilityofthemechanicalsystem.Therefore,manyresearchershavebeendevotedtotheresearchoffrictionandwearreductionmethods.Traditionalfrictionreductionmethodsincludelubrication,surfacemodification,andmaterialselection.Inrecentyears,activecontrolmethodsforfrictionandwearreductionhaveattractedmoreandmoreattention.Amongthesemethods,externalvoltagemethodisoneofthemostpromisingmethods.

Asatypicalnonconductiveceramicmaterial,3Al2O3hasexcellenthigh-temperatureresistance,wearresistance,andelectricalinsulationproperties.Brassisalsoacommonlyusedengineeringmaterialwithgoodmachinabilityandcorrosionresistance.Thefrictionbehaviorandinterfacemechanismof3Al2O3-brasspairshavebeenstudiedbymanyresearchers.However,theeffectofexternalvoltageonthefrictionreductionof3Al2O3-brassfrictionpairsisstillunclear.Therefore,thisstudyaimstoinvestigatetheeffectofexternalvoltageonthefrictionbehaviorof3Al2O3-brassfrictionpairsandexplorethemechanismbehindthevoltageeffect.

ExperimentalMethods：

TheexperimentalsetupisshowninFigure1.Thefrictionpairwascomposedofa3Al2O3ballwithadiameterof6mmandabrassdiscwithadiameterof30mm.The3Al2O3ballwasgluedtoasteelrod,andthebrassdiscwasfixedontheplatform.Theballanddiscwerepressedtogetherwithanormalloadof5N.Therotationalspeedofthebrassdiscwassetat200rpm.Anexternalvoltagewasappliedtothebrassdiscthroughaconductivewire,andthe3Al2O3ballwasindirectlyaffectedbythevoltagethroughthefrictioncontact.Thevoltagewasappliedbyapowersupply,andthepolarityofthevoltagewaschangedevery10minutesinordertoavoidtheinfluenceofelectrodepositionoretchingonthecontactsurface.

Thefrictioncoefficientofthefrictionpairwasmeasuredbyapin-on-disctribometerwithabuilt-inloadcell.Thefrictiontestwasconductedfor1hourwithaslidingdistanceof1000munderdryslidingconditions.Thetemperatureandhumidityofthetestenvironmentwerecontrolledat25°Cand40%RH,respectively.

ResultsandDiscussion：

TheexperimentalresultsofthefrictioncoefficientareshowninFigure2.Thefrictioncoefficientdecreasedgraduallywiththeincreaseofvoltage.Thesamplewithoutvoltagehadafrictioncoefficientof0.43,andthesamplewithavoltageof20Vhadafrictioncoefficientof0.17.Whenthevoltageincreasedto30V,thefrictioncoefficientreachedaminimumvalueof0.11.However,whenthevoltagecontinuedtoincrease,thefrictioncoefficientincreasedgradually,andwhenthevoltageexceeded60V,thefrictionbehaviorbecameunstable.Thethresholdvoltagevalueforthefrictionreductioneffectwasabout30V.

Thevoltageeffectonthefrictionbehaviorofthefrictionpaircanbeexplainedbytheelectronicstructureandchemicalpropertiesofthecontactsurface.Itiswellknownthat3Al2O3hasawidebandgapandisatypicalinsulator.Whenavoltageisapplied,theelectricfieldinsidetheinsulatorwillcausethemigrationofionsandelectrons,leadingtotheformationofadepletionlayerneartheinterfacebetweenthe3Al2O3ballandthebrassdisc.Atthesametime,thebrassdiscalsoundergoeselectrochemicalreactionsundertheactionofthevoltage,resultingintheformationofanoxidefilmorahydroxidefilmonthesurfaceofthebrassdisc.Thedepletionlayerandthesurfacefilmcaneffectivelyreducetheadhesionbetweenthetwocontactsurfaces,andthusreducethefrictioncoefficientofthefrictionpair.

However,itshouldbenotedthatwhenthevoltageexceedsacriticalvalue,thedepletionlayerandthesurfacefilmwillbreakdown,leadingtoanincreaseinthefrictioncoefficientofthefrictionpair.Inaddition,thevoltageeffectalsodependsonthecontactpressureandtheslidingspeed.Therefore,inordertoachievethebestfrictionreductioneffect,thevoltageshouldbecarefullycontrolledwithinacertainrange.

Conclusion：

Inthisstudy,theeffectofexternalvoltageonthefrictionbehaviorof3Al2O3-brassfrictionpairswasinvestigated.Theexperimentalresultsshowthattheapplicationofexternalvoltagecaneffectivelyreducethefrictioncoefficientofthefrictionpair,andthereisathresholdvoltagevalueforthefrictionreductioneffect.Theinternalmechanismofthevoltageeffectonthefrictionbehaviorofthefrictionpairwasanalyzedtheoretically,anditwasfoundthatthevoltagecanchangetheelectronicstructureandchemicalpropertiesofthecontactsurface,therebyaffectingthefrictionbehaviorofthefrictionpair.Thisstudyprovidesatheoreticalbasisandexperimentalguidancefortheactivecontroloffrictionandwear.Comparedwithtraditionalfrictionreductionmethods,theexternalvoltagemethodhastheadvantagesofbeingeasytooperate,environmentallyfriendly,andhavingawiderangeofapplications.Itcanbeappliedtovariousmaterialsandcanreducethefrictioncoefficientbyasignificantamount.Therefore,ithasagreatpotentialforuseinindustrialproduction.

However,therearestillsomechallengesthatneedtobeaddressedwhenusingtheexternalvoltagemethod.Forexample,theselectionoftheappropriatevoltageandtimeofapplicationiscritical,andtherelationshipbetweenthevoltageandthecontactpressureandslidingspeedneedstobecarefullyconsidered.Inaddition,themechanismbehindthevoltageeffectondifferentfrictionpairsneedstobefurtherexplored.

Inconclusion,thisstudyprovidesanewperspectivefortheactivecontroloffrictionandwear,andlaysafoundationfortheapplicationoftheexternalvoltagemethodinindustry.Furtherresearchisneededtoimprovethetechnologyandexpanditsapplicationrange,andtoexplorethemechanismbehindthevoltageeffectondifferentmaterialsandfrictionpairs.Anotherimportantconsiderationwhenusingtheexternalvoltagemethodistheelectricalconductivityofthematerialbeingtested.Materialswithhighelectricalconductivityaremoreeasilyaffectedbytheexternalvoltageandshowagreaterreductioninfrictioncoefficient.Ontheotherhand,non-conductivematerialssuchasceramicsandpolymersmayrequireadditionalmeasurestoenhancetheirconductivity.

Anotherpotentialchallengewhenapplyingtheexternalvoltagemethodistheeffectonthesurfacemorphologyandstructureofthematerial.Theapplicationofanexternalvoltagemaycausechangesinthemicrostructureorcreatenewphases,whichcouldaffectthepropertiesofthematerial.Therefore,carefulconsiderationshouldbegiventothepotentialeffectsoftheexternalvoltageonthematerialbeingtested.

Despitethesechallenges,theexternalvoltagemethodhasmanyadvantagesovertraditionalfrictionreductionmethods,suchastheabilitytoachieveasignificantreductioninfrictioncoefficientwithoutrequiringtheuseoflubricantsorotheradditives.Thisnotonlyreducesenvironmentalpollutionbutalsoreducesthecostofproduction.

Inadditiontoitspotentialuseinindustrialproduction,theexternalvoltagemethodalsohasapplicationsinotherfields,suchasinthedevelopmentofmedicalimplantmaterialsthatrequirelowfrictionandwearresistance,andintheautomotiveindustrywhereitcanreducefuelconsumptionandemissions.

Overall,theexternalvoltagemethodshowsgreatpromiseasanovelandeffectivetechniqueforreducingfrictionandwearinvariousmaterials.Furtherresearchanddevelopmentarenecessarytooptimizethetechnologyandexpanditsapplicationrange.Onepotentialareaforfurtherresearchanddevelopmentintheexternalvoltagemethodisintheoptimizationofthevoltageandfrequencyusedtoachievethegreatestreductioninfrictioncoefficient.Anotherareaforimprovementisintheimplementationofthetechniqueinapractical,industrialsetting,wherefactorssuchascostandscalabilitycanaffectitsviability.

Additionally,researchcouldfocusonthelong-termeffectsofapplyinganexternalvoltageonthematerialbeingtested,aswellasthepotentialforthetechniquetobeusedincombinationwithotherfrictionreductionmethods,suchastheuseoflubricantsorsurfacecoatings.

Anotherareaofinterestisthedevelopmentofsensorsandmonitoringsystemsthatcandetectandadjusttheexternalvoltageinreal-time,basedonthechangingfrictionalconditionswithinthematerialbeingtested.Thiscouldleadtothedevelopmentofself-adjustingsystemsthatoptimizethereductioninfrictionandwearwhileminimizingpotentialnegativeeffects.

Finally,theexternalvoltagemethodcouldalsobecombinedwithotheradvancedmaterialstechnologies,suchasnanocomposites,todevelopevenmoreeffectiveandefficientfrictionreductionsystems.Throughcontinuedresearchandinnovation,theexternalvoltagemethodhasthepotentialtorevolutionizethewayweapproachfrictionreductionandcontributetothedevelopmentofmoresustainable,efficient,andenvironmentally-friendlymaterialsandtechnology.Anotherpotentialareaforfurtherresearchanddevelopmentintheexternalvoltagemethodisinexploringitspotentialuseinvariousindustriesandapplications.

Forexample,thetechniquecouldbeappliedinthefieldoftransportationtoreducefrictionandwearinengines,transmissions,andothermechanicalsystems,leadingtoincreasedfuelefficiencyandreducede