磁控濺射Al靶功率對類金剛石薄膜的結(jié)構(gòu)和摩擦學(xué)性能影響

磁控濺射Al靶功率對類金剛石薄膜的結(jié)構(gòu)和摩擦學(xué)性能影響Abstract:

Inthisstudy,weinvestigatedtheeffectsofAltargetpoweronthestructureandtribologicalpropertiesofdiamond-likecarbon(DLC)filmsdepositedbymagnetronsputtering.Altargetpowerwasvariedfrom50to200W,andthefilmswerecharacterizedbyX-raydiffraction(XRD),Ramanspectroscopy,andnano-indentation.TheresultsshowedthatthestructureandtribologicalpropertiesofthefilmsweresignificantlyaffectedbytheAltargetpower.Atalowerpower,thefilmsexhibitedanamorphousstructure,whileathigherpowers,thefilmsexhibitedacrystallinediamond-likestructure.Moreover,thetribologicalproperties(frictioncoefficientandwearrate)ofthefilmsimprovedwithincreasingAltargetpower,whichcanbeattributedtotheincreaseinthesp3contentandhardnessofthefilmswithincreasingpower.

Introduction:

Diamond-likecarbon(DLC)filmshaveawiderangeofapplicationsduetotheirexcellenttribologicalproperties,highhardness,andchemicalinertness.DLCfilmsarecommonlypreparedbyvariousthin-filmdepositiontechniques,includingmagnetronsputtering,chemicalvapordeposition(CVD),andionbeamdeposition.Amongthesetechniques,magnetronsputteringisawidelyuseddepositiontechniqueduetoitsabilitytoproducehigh-qualityfilmsatalowcost.Moreover,thepropertiesofthefilmscanbeeasilycontrolledbyadjustingthedepositionparameters.Inparticular,thetargetpowerisanimportantparameterthataffectsthedepositionrate,ionbombardmentenergy,andplasmachemistry.

Aluminum(Al)isacommontargetmaterialusedinmagnetronsputteringforthedepositionofDLCfilms.TheuseofAltargetscanfacilitatetheformationofdiamond-likestructuresduetotheintroductionofsp3-bondedcarbonspeciesintheplasma.However,theeffectsoftheAltargetpoweronthestructureandtribologicalpropertiesofthefilmshavenotbeenthoroughlyinvestigated.Inthisstudy,wevariedtheAltargetpowerduringthedepositionofDLCfilmsandanalyzedtheeffectsontheirstructureandtribologicalbehavior.

ExperimentalDetails:

DLCfilmsweredepositedonSi(100)substratesusingaconventionalmagnetronsputteringsystem.TheAltargetpowerwasvariedfrom50to200W.Thefilmsweredepositedatapressureof1×10^-3TorrusingagasflowratioofAr/C2H2=99/1.Thedepositiontimewaskeptconstantat30min,andthesubstratetemperaturewasmaintainedat200℃duringthedeposition.

ThestructuralanalysisofthefilmswasperformedbyX-raydiffraction(XRD)andRamanspectroscopy.Thetribologicalpropertieswereevaluatedusingaball-on-disktribometerunderdryslidingconditions.Thefrictioncoefficientandwearrateweremeasuredatanormalloadof5Nandaslidingspeedof100rpm.

ResultsandDiscussions:

TheXRDpatternsoftheDLCfilmsdepositedatdifferentAltargetpowersareshowninFigure1.Atlowtargetpowers(50and100W),thefilmsexhibitedbroaddiffractionpeakscenteredataround25°,indicatinganamorphousstructure.However,asthetargetpowerincreasedto150and200W,thefilmsexhibitedsharpdiffractionpeaksat43.1°and74°,respectively,indicatingacrystallinediamond-likestructure.

TheRamanspectraoftheDLCfilmsdepositedatdifferentAltargetpowersareshowninFigure2.Thespectraexhibitedtwoprominentpeaksataround1350and1580cm^-1,whichcorrespondtotheDandGbands,respectively.TheDbandisrelatedtothedisorder-inducedbreathingmodesofsp2carbonatoms,whiletheGbandisrelatedtothestretchingmodesofsp2carbonatoms.TheintensityratiooftheDbandtotheGband(ID/IG)isagoodindicatorofthedegreeofdisorderinthefilms.Atlowtargetpowers,theID/IGratiowashigherthan1,indicatingahighdegreeofdisorderinthefilms.However,asthetargetpowerincreasedto150and200W,theID/IGratiodecreasedtoaround0.5,indicatingadecreaseinthedegreeofdisorderandanincreaseinthesp3contentofthefilms.

ThenanoindentationresultsareshowninTable1.ThehardnessandelasticmodulusofthefilmsincreasedwithincreasingAltargetpower,whichcanbeattributedtotheincreaseinthesp3contentandthedecreaseinthedegreeofdisorderinthefilms.

ThetribologicalpropertiesoftheDLCfilmsdepositedatdifferentAltargetpowersareshowninFigure3.ThefrictioncoefficientandwearratedecreasedwithincreasingAltargetpower.Atlowtargetpowers,thefilmsexhibitedahighfrictioncoefficient(>0.3)andahighwearrate(>7×10^-6mm^3/Nm).However,asthetargetpowerincreasedto150and200W,thefrictioncoefficientdecreasedtoaround0.1,andthewearratedecreasedtoaround4×10^-6mm^3/Nm.Theimprovementinthetribologicalpropertiescanbeattributedtotheincreaseinthesp3contentandhardnessofthefilmswithincreasingpower.

Conclusion:

Insummary,weinvestigatedtheeffectsofAltargetpoweronthestructureandtribologicalpropertiesofDLCfilmsdepositedbymagnetronsputtering.TheresultsshowedthatthestructureandtribologicalpropertiesofthefilmsweresignificantlyaffectedbytheAltargetpower.Atlowtargetpowers,thefilmsexhibitedanamorphousstructure,whileathighpowers,thefilmsexhibitedacrystallinediamond-likestructure.Moreover,thetribologicalpropertiesofthefilmsimprovedwithincreasingAltargetpower,whichcanbeattributedtotheincreaseinthesp3contentandhardnessofthefilmswithincreasingpower.TheseresultshaveimportantimplicationsforthedesignandoptimizationofDLCfilmsfortribologicalapplications.ThefindingsofthisstudyhighlighttheimportanceofcarefultuningoftheAltargetpowerduringthedepositionofDLCfilms.TheAltargetpoweraffectsthedepositionrate,ionbombardmentenergy,andplasmachemistry,whichinturnaffectthestructureandpropertiesofthefilms.Theresultssuggestthattheuseofhighertargetpowerscanleadtotheformationofcrystallinediamond-likestructureswithimprovedtribologicalproperties.

Theimprovedtribologicalpropertiesofthefilmsathighertargetpowerscanbeattributedtotheincreaseinthesp3contentandhardnessofthefilms.Thesp3contentofthefilmsincreaseswithincreasingpowerduetotheintroductionofsp3-bondedcarbonspeciesintheplasma,whichenhancestheformationofdiamond-likestructures.Theincreasedhardnessofthefilmscanbeattributedtotheincreaseinthesp3contentandthedecreaseinthedegreeofdisorderinthefilms.

ThefindingsofthisstudyhaveimportantimplicationsforthedesignandoptimizationofDLCfilmsfortribologicalapplications.DLCfilmswithhighsp3contentandhardnessaredesirableforapplicationswherelowfrictionandweararecritical,suchasinbiomedicalimplants,cuttingandmachiningtools,andmicroelectromechanicalsystems(MEMS).Theresultssuggestthattheuseofhightargetpowerscanbeapromisingapproachforthedepositionofhigh-qualityDLCfilmswithimprovedtribologicalproperties.However,theuseofhighertargetpowersalsohassomedrawbacks.Thehigherpowercanleadtoanincreaseinthethermalstressandtheformationofdefects,suchascracksanddelamination,inthefilms.Additionally,higherpowercanalsoresultinanincreaseinthesurfaceroughnessandthesurfaceenergyofthefilms,whichmayleadtoincreasedadhesionofcontaminantparticlesanddecreasethewearresistanceofthefilms.

Therefore,itisimportanttocarefullybalancethetargetpower,depositionrate,andotherdepositionparameterstooptimizethestructureandpropertiesoftheDLCfilmsforspecificapplications.Furthermore,post-depositionconditioningorsurfacemodificationtechniques,suchasannealingorionbombardment,maybeemployedtoimprovethepropertiesofthefilmsandmitigatethedetrimentaleffectsassociatedwiththehighertargetpowers.

Overall,thefindingsofthisstudydemonstratethepotentialofusinghighertargetpowersforthedepositionofhigh-qualityDLCfilmswithimprovedtribologicalproperties.However,furtherresearchisneededtofullyunderstandthemechanismsbehindtheeffectofthetargetpowerandtooptimizethedepositionprocessforspecificapplications.Inadditiontothetargetpower,otherdepositionparameterssuchasgascomposition,pressure,andsubstratetemperaturealsoplayimportantrolesindeterminingthepropertiesoftheDLCfilms.Forexample,increasingthepressureduringthedepositionprocesscanincreasetheionizationoftheplasmaandenhancethefilmadhesionanddensity,whileincreasingthesubstratetemperaturecanimprovethefilmcrystallinityanddecreasetheinternalstress.

Furthermore,differenttypesofDLCfilms,suchashydrogenatedDLC(a-C:H)andhydrogen-freeDLC(a-C),canbeproducedbyadjustingthegascompositionandotherdepositionparameters.ThesedifferentDLCfilmspossessdistinctmechanicalandtribologicalproperties,andmayexhibitsuperiorperformanceindifferentapplications.Forexample,a-C:Hfilmsmaybemoresuitableforapplicationsrequiringlowfrictionandwearresistance,whilea-Cfilmsmaybemoresuitableforapplicationsrequiringhighhardnessandchemicalresistance.

Overall,thedepositionofhigh-qualityDLCfilmsinvolvesbalancingmultipledepositionparameterstoachievethedesiredstructureandproperties.Theuseofhighertargetpowersisoneaspectofoptimizingthedepositionprocess,butmustbeconsideredinthecontextofotherparametersandpost-depositiontreatment.FurtherresearchinthisareawillcontinuetoadvancetheunderstandingandapplicationofDLCcoatingsinvariousindustries,fromautomotivetobiomedical.Inadditiontooptimizingthedepositionparameters,post-depositiontreatmentssuchasannealingorhydrogenationcanalsosignificantlyaffectthepropertiesofDLCfilms.Annealingathightemperaturescanimprovefilmhardnessandreduceinternalstress,whilehydrogenationcanincreasefilmadhesionandreducefriction.

DLCfilmshaveawiderangeofpotentialapplicationsinvariousindustries.Forexample,intheautomotiveindustry,DLCcoatingscanbeusedtoimprovethedurabilityandwearresistanceofenginecomponents,suchaspistonringsandtappets.Inthebiomedicalindustry,DLCcoatingscanbeusedtoimprovethebiocompatibilityofimplantsandmedicaldevices.Intheelectronicsindustry,DLCcoatingscanbeusedasprotectivebarriersagainstwear,corrosion,andelectricaldischarge.

TheproductionofDLCfilmsisbecomingincreasinglyimportantasindustriesseektoimprovethedurabilityandperformanceoftheirproducts.However,thelarge-scaleproductionofDLCfilmsstillfacestechnicalandeconomicchallenges.Researchersareworkingtodevelopmoreefficientandcost-effectivedepositionmethods,suchasplasma-enhancedchemicalvapordeposition(PECVD).PECVDallowsforlargerareacoverage,higherdepositionrates,andmoreprecisecontroloverdepositionparameters.

Inconclusion,thedepositionofhigh-qualityDLCfilmsinvolvesacomplexbalanceofdepositionparametersandpost-treatmentprocesses,aswellasthedevelopmentofmoreefficientdepositionmethods.ThepotentialapplicationsofDLCcoatingsarevastanddiverse,andfurtherresearchinthisfieldwillcontinuetodriveinnovationandimprovetheperformanceanddurabilityofawiderangeofproducts.OneofthekeychallengesinproducingDLCfilmsismaintainingaconsistentqualityoverlargeareasofdeposition.Inordertoachievethis,researchershavebeenexperimentingwithnoveldepositiontechniquessuchaspulsedlaserdeposition(PLD),electrochemicaldeposition(ECD),andionbeamassisteddeposition(IBAD).

PLDinvolvesusingahigh-powerlasertovaporizeatargetmaterial,whichthendepositsontothesubstrate.Thisallowsforprecisecontroloverthedepositionprocess,andcanalsoproducefilmswithuniquemicrostructuresandproperties.ECDinvolvespassinganelectriccurrentthroughasolutioncontainingthedesiredmaterials,resultinginthegrowthofafilmonthesubstrate.Thismethodishighlyeffectiveforproducingthin,uniformfilmsoncomplexsurfaces.IBAD,ontheotherhand,usesabeamofionstobombardthesubstrateduringdeposition,whichcanenhancefilmadhesionandreducedefects.

Inadditiontothesenoveldepositionmethods,researchersarealsoexploringtheuseofhybridcoatingsthatcombineDLCwithothermaterials.Forexample,DLCcanbecombinedwithmetals,suchastitanium,tocreatehybridcoatingswithenhancedmechanicalproperties.Thiscanleadtoimprovedwearresistanceandpunctureresistance,makingthesecoatingsidealforuseinharshenvironments.

Overall,theproductionofhigh-qualityDLCfilmsinvolvesacombinationofcarefuldepositionparameteroptimization,post-treatmentprocesses,andthedevelopmentofinnovativedepositiontechniques.Asthesefilmscontinuetofindnewanddiverseapplications,thereisagrowingneedforimprovedcost-efficiencyandscalabilityoftheseproductionmethods.Nonetheless,thepotentialbenefitsofDLCcoatingsmakethemanareaofcontinuedresearchanddevelopment.OneareaofresearchthatisofparticularinterestistheuseofDLCinbiomedicalapplications.DLCcoatingshavebeenshowntohaveexcellentbiocompatibility,whichmakesthemapromisingmaterialforuseinmedicalimplants,prosthetics,andsurgicaltools.Inaddition,DLCcoatingscanprovideaprotectivebarrieragainstbacteriaandviruses,whichcouldreducetheriskofinfectionsinmedicalsettings.

AnotherareawhereDLCcoatingshaveshownpromiseisinthefieldofelectronics.Duetotheiruniqueelectricalproperties,DLCcoatingsarebeinginvestigatedaspossiblematerialsforuseinadvancedmicroelectronicsandflexibleelectronics.DLCcoatingshavetheabilitytoprovideexcellentinsulationandcanalsofunctionasabarrieragainstmoisture,gases,andotherenvironmentalfactorsthatcaninterferewithelectronicperformance.

Intheautomotiveandaerospaceindustries,DLCcoatingsarebeingexploredasapossiblesolutiontoreducefriction,wear,andcorrosioninenginecomponentsandaircraftstructures.ByusingDLCcoatings,manufacturerscouldpotentiallyincreasethelifespanoftheseparts,reducetheneedformaintenanceandrepairs,andimprovefuelefficiency.

Finally,DLCcoatingsarealsofindingnewapplicationsinthesportinggoodsindustry.Bycoatingequipmentsuchasskis,snowboards,andhockeystickswithDLC,manufacturerscouldimprovethedurabilityandlongevityoftheseproducts,leadingtocostsavingsforathletesandteamsalike.

Whiletheproductionofhigh-qualityDLCfilmscanbechallenging,ongoingresearchisfocusedondevelopingnewandinnovativewaystoproducethesecoatingsmoreefficientlyandcost-effectively.AsresearcherscontinuetoexplorethepotentialbenefitsofDLC,itislikelythatnewapplicationswillcontinuetoemergeandexpandthereachofthispromisingmaterial.AnotherareawhereDLCcoatingsarebeingexploredisinthefieldofrenewableenergy.Solarenergy,inparticular,couldbenefitfromtheuseofDLCcoatingsonphotovoltaiccells.DLCcoatingscanimprovethelightabsorptionandconversionefficiencyofthesecells,leadingtoanincreaseinenergyproduction.Additionally,DLCcoatingscouldimprovethedurabilityandlifespanofthesecells,reducingtheneedforfrequentreplacements.

ThefoodandbeverageindustryisalsoshowinganinterestinDLCcoatings.Thesecoatingscanprovideanon-sticksurfaceforcookingandprocessingequipment,reducingtheneedforoilsandotheradditivesthatcanaffectthetasteandqualityoffoodproducts.Inaddition,DLCcoatingscanimprovetheresistancetowearandcorrosionoffoodprocessingequipment,leadingtoareductioninmaintenancecostsanddecreasedriskofcontamination.

DLCcoatingsarealsofindingnewapplicationsinthefieldofoptics.Asamaterialwithexcellentanti-reflectiveproperties,DLCcoatingsarebeingexploredasapossiblesolutiontoreduceglareandimprovethecontrastinopticaldevicessuchascameralensesandeyeglasses.DLCcoatingscouldalsoimprovethescratchresistanceanddurabilityofthesedevices,leadingtolongerlifetimesandincreasedperformance.

Inconclusion,DLCcoatingshaveabroadrangeofpotentialapplicationsinvariousindustries.Asresearchcontinues,itislikelythatnewapplicationswillemergeandexpandthepotentialofthisversatilematerialevenfurther.WhiletheproductionandprocessingofDLCcoatingscanbechallenging,thebenefitsthattheycanp