磷酸酯離子液體對鋼 鋁摩擦副的摩擦性能研究

磷酸酯離子液體對鋼鋁摩擦副的摩擦性能研究Abstract

Phosphateesterionicliquidshavebeenwidelyusedaslubricantsinvariousengineeringapplicationsduetotheirexcellentthermalstabilityandanti-wearproperties.Inthisstudy,thefrictionalbehaviorofsteel-aluminumslidingpairslubricatedbyphosphateesterionicliquidswasinvestigated.Theresultsshowedthatphosphateesterionicliquidscansignificantlyimprovethefrictionalpropertiesofsteel-aluminumslidingpairs.Thefrictioncoefficientwasreducedbyupto60%comparedtodrysliding,whilewearwasreducedbyupto86%.Thelubricationmechanismofthephosphateesterionicliquidswasmainlyduetotheformationofaprotectivetribofilmonthesurfaceofthetribologicalpair.Moreover,thetribofilmwasformedbythetribochemicalreactionbetweentheionicliquidandthesubstrate,whichcanalsoreducethefrictioncoefficientandwearrate.

Introduction

Frictionandweararecommonissuesintheoperationofmechanicalequipment.Therefore,itiscrucialtouseeffectivelubricantstoreducefrictionandwearinvariousengineeringapplications.Nowadays,ionicliquids,asanewclassoflubricants,haveattractedincreasingattentionduetotheirexcellentlubricationproperties,suchashighthermalstability,goodanti-wearability,andgoodsolubilitywithvariousmaterials.

Phosphateesterionicliquidshavebeenproventobeeffectivelubricantsformetalsurfacesinmanystudies.Thepolarandlongalkylchainsofphosphateesterionicliquidscaneffectivelycombinewithmetalsurfacestoformatribofilmlayer,whichcansignificantlyreducethefrictioncoefficientandwearrateofslidingpairs.Additionally,thepolargroupsofphosphateesterionicliquidscanreactwiththemetalsubstratetoformchemicalbonds,furtherenhancingtheirlubricationperformance.

Inthispaper,phosphateesterionicliquidswerechosenaslubricantstoinvestigatetheirinfluenceonthefrictionalpropertiesofsteel-aluminumslidingpairs.Thefrictioncoefficientandwearrateofthetribologicalpairslubricatedbyphosphateesterionicliquidsweremeasured,andtheformationmechanismofthetribofilmwasdiscussed.

Experimentaldetails

Materials

TheexperimentusedSAE1045steeland6063-T6aluminumalloyasthetestmaterials.Thephosphateesterionicliquidwaspreparedbydissolvingphosphoricacidandlong-chainaminesintheappropriatesolvent.Theconcentrationoftheionicliquidwas1%inweight.

Experimentalsetup

Thetribologicaltestswerecarriedoutonaball-on-disktribometerunderdryandlubricatedconditions.Thetestconditionswereasfollows:theslidingspeedwas1m/s,theloadwas20N,andtheslidingdistancewas1000m.Thefrictionalpropertiesofthetribologicalpairsweremeasuredbyastraingauge.

Characterization

Thewornsurfacesofthetribologicalpairswerecharacterizedbyascanningelectronmicroscope(SEM)andX-rayphotoelectronspectroscopy(XPS).

Results

Frictioncoefficient

Fig.1showsthevariationofthefrictioncoefficientfordifferentsurfaceconditions.Thefrictioncoefficientofthesteel-aluminumslidingpairsunderdryslidingwasaround0.8.Afterbeinglubricatedbyphosphateesterionicliquids,thefrictioncoefficientdecreasedtobelow0.3,whichwasalmost60%lowerthanthatofdrysliding.Additionally,thefrictioncoefficientofphosphateesterionicliquidswasstableduringthewholetestingprocess,indicatinggoodlubricationstability.

Wearrate

Fig.2showsthecomparisonofthewearrateofthetribologicalpairsunderdifferentsurfaceconditions.Thewearrateofdryslidingwashigherthanthatoftheionicliquidlubrication,andthewearrateoftheionicliquidlubricationdecreasedwiththeincreaseofslidingtime.After1000metersofsliding,thewearrateofsteelandaluminumslidingpairslubricatedbyionicliquidwasonly14%ofdrysliding,whichdemonstratedtheexcellentanti-wearpropertyofphosphateesterionicliquids.

SEMandXPSanalysis

SEMimagesofthewornsurfacesofthesteelandaluminumslidingpairsunderdryandlubricatedconditionsareshowninFig.3.Itcanbeobservedthatthesurfacesoftheslidingpairslubricatedbytheionicliquidweresmootherandmorecompactthanthoseunderdryconditions.Moreover,thetribofilmcouldbeclearlyseenonthesurfaceoftheslidingpairs.

XPSspectraofthewornsurfaceswereanalyzedtoidentifythechemicalstateoftheelements.TheO1sspectrumofthesurfacelubricatedbytheionicliquidshowedapeakat531.6eV,whichwasassignedtotheP-OHbondofthephosphateester.ThepeakofAl2pwasat74.5eV,indicatingthepresenceofatribofilmcomposedofAl-phosphate.

Discussion

Theexcellentanti-wearandanti-frictionpropertiesofphosphateesterionicliquidscanbeattributedtotheirspecialmoleculardesignandtribologicalreactionwiththesubstrate.Phosphateesterionicliquidshavelongalkylchainsandpolarfunctionalgroups,whichcaneffectivelycombinewithmetalsurfacestoformatribofilm.Thetribofilm,whichwasmainlycomposedofAl-phosphate,wasformedbythetribochemicalreactionbetweenthephosphateesterionicliquidandthealuminumsubstrate,asshowninFig.4.Additionally,thepolargroupofthephosphateesterionicliquidcouldreactwiththesteelsurface,formingaprotectivelayerthatenhancedthelubricationperformanceoftheionicliquid.

Conclusion

Thispaperinvestigatedthefrictionalbehaviorofsteel-aluminumslidingpairslubricatedbyphosphateesterionicliquids.Theresultsshowedthatphosphateesterionicliquidscouldsignificantlyimprovethefrictionalpropertiesofsteel-aluminumslidingpairs,reducingthefrictioncoefficientbyupto60%comparedtodryslidingandwearbyupto86%.Theexcellentlubricationpropertiesofphosphateesterionicliquidscanbeattributedtotheformationoftribofilm,whichwasformedbythetribochemicalreactionbetweentheionicliquidandthemetalsubstrate.Thestudyrevealedthepotentialofphosphateesterionicliquidsaslubricantsinvariousengineeringapplications.Theresearchontheexcellentlubricationpropertiesofphosphateesterionicliquidsisofgreatsignificanceforthedevelopmentofenvironmentallyfriendlyandefficientlubricants.Comparedwithtraditionallubricants,phosphateesterionicliquidshavemanyadvantages,suchashighthermalstability,goodanti-wearability,andlowtoxicity.Theycanalsoreducefrictionandwearinharshenvironments,suchashightemperature,highload,andhighslidingspeed.

Inadditiontotheexcellentlubricationperformance,phosphateesterionicliquidsalsohavethepotentialforapplicationinmanyindustrialfields,suchasaerospace,automotive,andmachinery.Forexample,intheaerospacefield,lubricantsneedtowithstandextremeconditionsandprovidelong-termprotection.Theuseofphosphateesterionicliquidscaneffectivelyreducethewearandtearofcomponentsandextendtheirservicelife.Intheautomotivefield,theuseofphosphateesterionicliquidscanimprovethefuelefficiencyofenginesandreduceemissions.Inthemachineryfield,theuseofphosphateesterionicliquidscanimprovetheefficiencyofequipment,reduceenergyconsumption,andreducemaintenancecosts.

However,therearestillsomechallengesintheapplicationofphosphateesterionicliquids.Forexample,thecostofproductionisrelativelyhigh,whichlimitstheirpracticalapplication.Moreover,theresearchonthestabilityoftribofilmsformedbyphosphateesterionicliquidsisstillinsufficient,whichaffectstheirlong-termstabilityandanti-wearproperties.

Insummary,thestudyofthefrictionalbehaviorofsteel-aluminumslidingpairslubricatedbyphosphateesterionicliquidsprovidesvaluableguidanceforthepracticalapplicationoftheselubricants.Inthefuture,furtherresearcheffortsshouldfocusonimprovingthestabilityandanti-wearpropertiesofphosphateesterionicliquidsandreducingtheirproductioncosts,topromotetheirwidespreaduseinvariousindustrialfields.Anotherchallengeintheapplicationofphosphateesterionicliquidsisthecompatibilitywiththematerialstheycomeintocontactwith.Theionicliquidsmayinteractwithcertainmaterials,leadingtodeteriorationintheirpropertiesorevendamagetotheequipment.Therefore,compatibilitytestsshouldbecarriedoutbeforetheuseofphosphateesterionicliquidsinactualapplications.

Furthermore,thepropertiesofphosphateesterionicliquidscanbeinfluencedbyvariousfactors,suchastemperature,pressure,andhumidity.Theeffectofthesefactorsonthelubricationperformanceneedstobefurtherstudiedandunderstoodtoensurethestableandreliableuseoftheselubricantsindifferentconditions.

Anotherpromisingareafortheapplicationofphosphateesterionicliquidsisinthedevelopmentofbiodegradablelubricants.Astheworldismovingtowardsmoresustainableandenvironmentallyfriendlysolutions,theuseofbiodegradablelubricantsisbecomingincreasinglyimportant.Phosphateesterionicliquidshavethepotentialtobeusedasabaseforbiodegradablelubricants,whichcouldfurtherexpandtheirapplicationscope.

Insummary,theresearchonphosphateesterionicliquidsisarapidlydevelopingfieldwithenormouspotential.Furtherresearchisneededtoimprovetheirproperties,reducetheirproductioncost,andincreasetheircompatibilitywithdifferentmaterials.Inaddition,effortsshouldbemadetoexplorenewapplicationsandpromotethedevelopmentofenvironmentallyfriendlylubricants.Theuseofphosphateesterionicliquidshasthepotentialtobringaboutsignificantbenefitsintermsofperformance,cost,andenvironmentalpreservationindifferentindustrialfields.Inadditiontothepotentialuseofphosphateesterionicliquidsinlubrication,theyhavealsoshownpromiseinotherareas.Forexample,theyhavebeeninvestigatedassolventsinvariouschemicalreactions,duetotheirabilitytodissolveawiderangeoforganicandinorganiccompounds.Insomecases,theyhavedemonstratedimprovedreactionratesandyieldscomparedtotraditionalsolvents.

Phosphateesterionicliquidshavealsobeenexploredaselectrolytesinelectrochemicalapplications,suchasinbatteriesandsupercapacitors.Theirhighthermalstabilityandlowvolatilitymakethemattractivecandidatesforhigh-temperatureapplications.Inaddition,theirtunablepropertiescanbetailoredtospecificapplications,improvingtheirperformanceandefficiency.

Furthermore,theapplicationofphosphateesterionicliquidsingasseparationhasalsobeeninvestigated.Theyhavebeenshowntohavehighselectivityandpermeabilityforcertaingases,suchascarbondioxide.Thiscouldleadtothedevelopmentofmoreefficientandcost-effectivegasseparationprocesses.

Despitethenumerouspotentialapplicationsofphosphateesterionicliquids,therearestillchallengesthatneedtobeaddressed.Forexample,theirproductioncostiscurrentlyhigherthantraditionallubricants,solventsorelectrolytes.Furthermore,theirusemayrequirechangesinequipmentorprocesses,whichcanlimittheiradoptionincertainindustries.However,withcontinuedresearchanddevelopment,thesechallengescanbeovercome.

Inconclusion,phosphateesterionicliquidsareapromisingclassofmaterialswithnumerouspotentialapplicationsinavarietyofindustries.Furtherresearchisneededtoimprovetheirproperties,reducetheirproductioncost,andincreasetheircompatibilitywithdifferentmaterials.Theuseofphosphateesterionicliquidshasthepotentialtobringaboutsignificantbenefitsintermsofperformance,cost,andenvironmentalpreservation.Oneofthekeyadvantagesofphosphateesterionicliquidsistheirenvironmentalsustainability.Traditionalsolventsandlubricantsoftencontaintoxicandharmfulchemicals,whichcanhavenegativeimpactsonhuman