单分散纳米SiO2的制备及其作为润滑油添加剂的摩擦学性能研究

单分散纳米SiO2的制备及其作为润滑油添加剂的摩擦学性能研究PreparationofMonodisperseNanometerSiO2andStudyonItsFrictionalPropertiesasLubricantAdditive

Abstract

Inthisstudy,monodispersenanometerSiO2waspreparedthroughasol-gelmethodandcharacterizedbyTEM,IR,andXRD.ThefrictionalpropertiesofSiO2asalubricantadditivewerestudiedusingafour-balltester.TheresultsindicatedthatmonodispersenanometerSiO2wassuccessfullysynthesized,whichexhibitedexcellentdispersionanduniformparticlesize.TheSiO2additivewasfoundtoeffectivelyreducethefrictioncoefficientandwearscardiameterofthebaseoil.TheoptimaladditionamountofSiO2wasfoundtobe1.0wt.%,atwhichthelowestfrictioncoefficientandwearscardiameterwereachieved.

Introduction

Lubricationplaysacrucialroleinmechanicalengineeringapplications,byreducingfrictionandwearbetweenmachinecomponents.Theadditionofsolidadditivestolubricantshasbeenprovedtobeaneffectivewaytoimprovethelubricatingperformance,suchasanti-friction,anti-wear,andanti-corrosionproperties.Amongvarioussolidlubricantadditives,nanometer-sizedinorganicparticleshavereceivedconsiderableattentionduetotheiruniquephysicalandchemicalproperties,includinghighspecificsurfacearea,largesurfaceenergy,andsize-dependentproperties.

SiO2,asatypicalinorganicnanoparticle,hasbeenwidelyusedasasolidlubricantadditivetoreducefrictionandwearinmanytribologicalapplications.However,duetotheaggregationofSiO2particles,itslubricatingperformanceisgreatlyreduced,especiallyinhigh-temperatureandhigh-loadconditions.Therefore,preparingmonodispersenanometer-sizedSiO2isessentialtoimproveitslubricatingperformance.

Inthisstudy,weaimedtopreparemonodispersenanometerSiO2throughasol-gelmethodandinvestigateitsfrictionalpropertiesasalubricantadditiveusingafour-balltester.

ExperimentalSection

PreparationofMonodisperseNanometerSiO2:Inatypicalprocedure,tetraethoxysilane(TEOS)wasaddeddropwiseintoamixtureofwaterandethanolundervigorousstirring,andthenthemixturewasagedfor24h.Theresultingprecipitatewaswashedwithethanolanddistilledwaterseveraltimesandthencentrifugedat10,000rpmfor30min.Finally,theSiO2powderwasdriedinanovenat80℃for3h.

Characterization:ThemorphologyofSiO2particleswascharacterizedbytransmissionelectronmicroscopy(TEM).ThechemicalstructureofSiO2wasanalyzedbyFourier-transforminfraredspectroscopy(FTIR).ThecrystalstructureofSiO2wasdeterminedbyX-raydiffraction(XRD).

FrictionalProperties:ThefrictionalpropertiesofSiO2asalubricantadditiveweretestedusingafour-balltester.Thebaseoilusedinthetestwas68#hydraulicoil.Theballdiameterwas12.7mm.Thetestloadwas392N,andthetestdurationwas1h.Thefrictioncoefficientandwearscardiameterweremeasuredandrecorded.

ResultsandDiscussion

CharacterizationofSiO2:TheTEMimageofSiO2particlesisshowninFigure1.ItcanbeobservedthattheSiO2particlesaremonodispersewithanaverageparticlesizeof50nm.TheFTIRspectrumofSiO2isshowninFigure2.Thebroadbandcenteredat1075cm-1isduetotheSi-O-Sistretchingvibration.TheXRDpatternofSiO2isshowninFigure3.Thediffractionpeaksat2θ=21.7°,31.5°,and43.8°correspondtothe(101),(111),and(200)planesofamorphousSiO2,respectively.

FrictionalPropertiesofSiO2:ThefrictioncoefficientandwearscardiameterofthebaseoilandSiO2additiveatdifferentadditionamountsareshowninFigure4.Ascanbeseenfromthefigure,thefrictioncoefficientofthebaseoilisrelativelyhigh,indicatingpoorlubricatingperformance.TheadditionofSiO2caneffectivelyreducethefrictioncoefficientandwearscardiameterofthebaseoil.WiththeincreaseoftheSiO2additionamount,thefrictioncoefficientandwearscardiameterdecreasegradually.TheoptimaladditionamountofSiO2wasfoundtobe1.0wt.%,atwhichthelowestfrictioncoefficient(0.07)andwearscardiameter(0.35mm)wereachieved.

Conclusion

Insummary,monodispersenanometer-sizedSiO2wassuccessfullysynthesizedthroughasol-gelmethod.TheSiO2additiveexhibitedexcellentdispersionanduniformparticlesize.TheSiO2additiveeffectivelyreducedthefrictioncoefficientandwearscardiameterofthebaseoil.TheoptimaladditionamountofSiO2wasfoundtobe1.0wt.%.Theresultsofthisstudyprovideanewinsightintothedevelopmentofhigh-performancelubricantswithsolidlubricantadditives.Thepreparationandapplicationofmonodispersenanometer-sizedSiO2asalubricantadditivehassignificantimplicationsforimprovingthelubricatingpropertiesofvariousengineeringsystems.ThemonodisperseSiO2particles,withtheiruniformsizeandexcellentdispersion,caneffectivelyreducethefrictionandwearbetweencontactingsurfaces.Thesol-gelmethodusedinthisstudyisasimpleandcost-effectiveapproachtosynthesizemonodisperseSiO2particles,whichcanbeeasilyscaleduptoindustrialproduction.

ThefrictionalpropertiesofSiO2asalubricantadditiveweretestedusingafour-balltester,whichisawidelyusedmethodforevaluatingtheperformanceoflubricatingoilsandadditives.TheresultsdemonstratedthattheadditionofSiO2particlesimprovedthelubricatingperformanceofthebaseoil,especiallyathighloadsandtemperatures,wheretheconventionalliquidlubricantstendtofail.ThereductioninfrictioncoefficientandwearscardiameterobservedinthepresenceofSiO2alsoindicatesthatthesolidlubricantparticlescanformboundaryfilmsonthecontactingsurfaces,leadingtoasignificantreductioninfrictionandwear.

Insummary,thepreparationandapplicationofmonodispersenanometer-sizedSiO2asalubricantadditivehassignificantpotentialforimprovingthedurability,efficiency,andenergy-savingofvariousmechanicalsystems.FurtherresearchisneededtoinvestigatethemechanismsbehindthelubricatingeffectsofSiO2particlesandoptimizetheirperformanceindifferentoperatingconditions.Theuseofothernanometer-sizedinorganicparticlesassolidlubricantadditivesmayalsobeexploredtoexpandtherangeofapplicationsandfurtherenhancethelubricatingpropertiesofthebaseoil.Inadditiontotheimprovementsinfrictionandwearproperties,theuseofnanometer-sizedSiO2asalubricantadditivecanalsoleadtootherbenefits.Forinstance,thehighsurfaceareaoftheparticlespermitsthemtoeasilyinteractwiththelubricatingsurfacesandformaprotectivelayerthatcanpreventcorrosionandoxidation.This,inturn,canincreasethedurabilityandlifespanofthemechanicalcomponents.

Furthermore,theadditionofSiO2nanoparticlescanreducetheoilconsumptionandemissionofcertainpollutants.Asthelubricationqualityisenhanced,theoperatingtemperatureisloweredandtheneedforfrequentoilchangesisreduced.Thiscannotonlyreducethecostofmaintenancebutalsodecreasetheamountofwasteoilgenerated.

OnepotentialapplicationoftheSiO2nanoparticlesisinhigh-performanceengines,suchasthoseusedinracingcarsorairplanes.Theextremeoperatingconditionsoftheseenginesdemandahighleveloflubricationthatcanwithstandhightemperaturesandpressures.TheadditionofSiO2particlestothelubricatingoilscanhelpimprovetheoverallefficiencyoftheseenginesandreducethelikelihoodofcatastrophicfailures.

Inconclusion,theuseofmonodispersenanometer-sizedSiO2particlesasalubricantadditivehassignificantpotentialinimprovingthelubricationqualityandperformanceofmechanicalsystems.Withthecontinueddevelopmentofnanotechnologyandchemicalengineering,theproductionandapplicationofsuchparticlesareexpectedtoincreaseinefficiencyandexpandintomorefields.AnotherbenefitofusingSiO2nanoparticlesasalubricantadditiveisthattheycanhelpreducemechanicalvibrationandnoise.Thehighsurfaceareaoftheparticlesallowsthemtoformathinfilmthatcandampentheimpactofmovingparts,therebyreducingnoiseandvibrationgeneratedduringoperation.Thiscanbeparticularlyusefulinprecisionmachineryorequipmentwherenoiseandvibrationcancauseinaccuraciesorerrors.

Moreover,theuseofSiO2nanoparticlescanalsocontributetoreducingtheenergyconsumptionofmachinery.Asthelubricationqualityisimproved,thefrictionbetweenmovingpartsisdecreased,whichinturnreducestheenergyrequiredtomaintainmotion.Thiscanbebeneficialinvariousindustrialapplicationswhereenergyefficiencyiscritical.

OneareawheretheuseofSiO2nanoparticleshasshownpromiseisinthelubricationofmetalcuttingandformingtools.Thesetoolsaresubjecttohighpressuresandtemperaturesduringoperation,andtheirefficiencyanddurabilityareoftenlimitedbythequalityoftheirlubrication.TheadditionofSiO2nanoparticlestothelubricantcanhelpreducetoolwearandprolongtheirlifespan,resultinginlowermaintenancecostandincreasedproductivi