ZDDP作用下鎢 鉬膜的摩擦化學(xué)潤滑機理研究

ZDDP作用下鎢鉬膜的摩擦化學(xué)潤滑機理研究TheStudyofFrictionalChemicalLubricationMechanismofTungstenandMolybdenumFilmsundertheActionofZDDP

Abstract:

InordertoexplorethefrictionalchemicallubricationmechanismoftungstenandmolybdenumfilmsundertheactionofZDDP,thispaperinvestigatedthetribologicalpropertiesofthefilmsusingaball-on-disktribometer,X-rayphotoelectronspectrometer(XPS),andscanningelectronmicroscope(SEM).TheresultsshowedthatthefrictioncoefficientdecreasedsignificantlywiththeadditionofZDDP,whichcouldformaprotectivefilmonthesurfaceofthefilm.Atthesametime,XPSandSEManalysesshowedthatZDDPcouldchemicallyadsorbonthesurfaceofthefilm,formingamolecularlevelprotectivefilm,whichplayedanimportantroleinreducingfrictionandwear.

Introduction:

Metalssuchastungstenandmolybdenumarewidelyusedinindustrialfieldsduetotheirexcellentmechanicalpropertiessuchashighstrength,wearresistance,andcorrosionresistance.However,duetotheirhighsurfaceenergyandinherentinstability,thefilmseasilyundergooxidationandwear,leadingtoadeclineintheirperformance.Therefore,itisnecessarytoexploreeffectivelubricationstrategiestosolvetheproblemoffilmwear.

ZDDP(zincdialkyldithiophosphate)hasbeenwidelyusedinthefieldoflubricationduetoitsexcellentanti-wearandanti-oxidationproperties.IthasbeendemonstratedthatZDDPcouldformaprotectivefilmonthesurfaceofthematerial,reducingfrictionandwear.ThechemicaladsorptionofZDDPonthesurfaceofthematerialhasasignificantimpactonitswearproperties.

Inthisstudy,aball-on-disktribometerwasusedtoinvestigatethefrictionandwearpropertiesoftungstenandmolybdenumfilmsundertheactionofZDDP,andXPSandSEManalyseswereconductedtoexplorethefrictionalchemicallubricationmechanismofthefilms.

Experimentalsection:

Materialspreparation:

Tungstenandmolybdenumfilmsweredepositedonsiliconsubstratesbyionbeamsputtering(IBS)withathicknessofabout200nm,andthenannealedat800℃invacuumfor2hours.TheZDDPlubricantwasobtainedfromSigma-Aldrich,withapurityof98%.

Tribologicaltesting:

Thefrictionandwearpropertiesofthefilmsweretestedusingaball-on-disktribometer(UMT-3,CETRInc.,Campbell,CA,USA).A6-mmsteelballwasusedasthecounterface,andtheloadwassetat5N.Theslidingspeedwas0.2m/s,andtheslide-to-rotationratiowas2:1.Beforeeachtest,thediskwascleanedwithethanolanddriedinair.

Characterization:

X-rayphotoelectronspectrometer(XPS,AxisUltraDLD,KratosCorp.,Manchester,UK)wasusedtoanalyzethecompositionandchemicalbondingstateofthefilms.Thescanningelectronmicroscope(SEM,Quanta200FEG,FEI,Hillsboro,OR,USA)wasusedtoobservethesurfacemorphologyofthefilmsbeforeandafterfrictiontesting.

ResultsandDiscussion:

ThefrictioncoefficientoftungstenandmolybdenumfilmswithandwithouttheadditionofZDDPlubricantisshowninFig.1.ItcanbeseenthatthefrictioncoefficientofthefilmsdecreasedsignificantlyaftertheadditionofZDDP,indicatingthatZDDPhasagoodlubricatingeffectonthefilms.Thedecreaseinfrictioncoefficientmaybeduetotheformationofaprotectivefilmonthesurfaceofthematerial,whicheffectivelyreducesthecontactbetweenthetwoslidingsurfaces.

TheXPSspectraoftungstenandmolybdenumfilmsbeforeandafterfrictiontestingareshowninFig.2.Itisobservedthatafterfrictiontesting,thepeakheightsofO1sandS2pincreasedsignificantly,indicatingthatoxidationandsulfidationoccurredonthesurfaceofthefilms.However,aftertheadditionofZDDP,thechangesinO1sandS2pweresignificantlyreduced,whichshowedthattheadsorptionofZDDPonthesurfaceofthefilmscouldeffectivelyinhibittheoxidationandsulfidationofthefilms.

TheSEMimagesoftungstenandmolybdenumfilmsbeforeandafterfrictiontestingareshowninFig.3.Itcanbeseenthatbeforefrictiontesting,thesurfacesofthefilmswererelativelysmooth.However,afterfrictiontesting,thesurfacesofthefilmsbecamerough,indicatingthatwearoccurredonthesurfacesofthefilms.AftertheadditionofZDDP,thesurfacesofthefilmsbecamesmoother,whichindicatedthatZDDPcouldeffectivelyinhibitthewearofthefilms.

Conclusion:

Insummary,thisstudyinvestigatedthefrictionalchemicallubricationmechanismoftungstenandmolybdenumfilmsundertheactionofZDDP.ItwasfoundthattheadditionofZDDPcouldeffectivelyreducethefrictioncoefficientofthefilmsandinhibittheoxidationandsulfidationofthefilms.TheresultsofXPSandSEManalysesshowedthatZDDPcouldchemicallyadsorbonthesurfaceofthefilms,formingamolecularlevelprotectivefilm,whichplayedanimportantroleinreducingfrictionandwear.Thisstudyprovidesatheoreticalbasisandtechnicalsupportforthelubricationoftungstenandmolybdenumfilmsinpracticalapplications.Furthermore,thisstudyrevealstheimportantroleplayedbyZDDPinmitigatingtheoxidationandsulfidationmechanismsthattypicallyleadtowearandfailureofmetallicfilms.TheresultssuggestthatZDDPcouldbeusedasanexcellentlubricantforarangeofmetalfilmstoimprovetheirtribologicalproperties.

ThemechanismbywhichZDDPformsaprotectivefilmonthesurfaceofthemetalfilmsismainlyattributedtothechemicaladsorptionphenomenon,inwhichthemoleculesofthelubricantattachtothesurfaceofthemetalfilmbyformingchemicalbonds.Moreover,theuseofZDDPinlubricationhasmanyadvantages,notonlyimprovingthetribologicalperformanceofmetalfilmsbutalsoofferinglowfriction,stabilityathightemperatures,andhighanti-wearproperties.

Asaresult,thestudyofthetribologicalpropertiesofmetalfilmsundertheactionofZDDPisofsignificantimportanceinthefieldofmaterialscienceandengineering.Itprovidesinsightsintothelubricationmechanismsofmetalfilmsunderspecificconditions,whichcancontributetothedevelopmentofnovellubricantsandtheimprovementofmaterialsinengineeringapplications.

Inconclusion,thisstudyprovidesfundamentalunderstandingofthefrictionalchemicallubricationmechanismoftungstenandmolybdenumfilmsundertheactionofZDDP.TheresultsshowedthatZDDPplaysacrucialroleinreducingfrictionandwear,andcouldformamolecularlevelprotectivefilmonthesurfaceofthefilms.Therefore,theuseofZDDPasalubricantformetallicfilmscansignificantlyimprovetheirtribologicalpropertiesandhaspracticalsignificanceinthefieldofmaterialscienceandengineering.Inadditiontoitsbenefitsforspecificmetalfilms,thestudyofZDDPanditstribologicalpropertieshasbroaderimplicationsforindustriesthatrelyonlubrication.Lubricationisessentialforawiderangeofapplications,fromautomotiveenginestoaerospacesystems,andhasasignificantimpactontheefficiencyandlifespanofthesemachines.

Whiletraditionallubricantshavebeeneffectiveinmanyapplications,thereisincreasingdemandforlubricantsthatcanperformundermoreextremeconditions,suchashightemperaturesandpressures,andinharshchemicalenvironments.UnderstandingthemechanismsbywhichZDDPenhanceslubricationcanaidinthedevelopmentofmoreeffectivelubricantsfortheseapplications.

Furthermore,theuseofZDDPcouldalsohaveanimpactontheenvironmentalsustainabilityoflubrication.Traditionallubricantsareoftenbasedonnon-renewableresourcesandcancontributetopollutionandwaste.Byimprovingtheefficiencyoflubrication,ZDDPcouldreducetheamountoflubricantneededandenhancethelifespanofmachines,potentiallyreducingtheenvironmentalimpactoflubrication.

Overall,thestudyofZDDPanditsroleintribologicalpropertieshassignificantimplicationsforindustriesthatrelyonlubrication,aswellasforthelargergoalofsustainablematerialsengineering.Furtherresearchinthisareacouldleadtothedevelopmentofmoreeffectivelubricantsforawiderangeofapplications,withbenefitsforbothindustryandtheenvironment.Inadditiontoitspotentialbenefitsinimprovinglubricationefficiencyandsustainability,thestudyofZDDPanditstribologicalpropertiescanalsocontributetoadeeperunderstandingofthefundamentalprinciplesoffrictionandwear.

Tribology,thestudyofinteractingsurfacesinmotion,isacomplexfieldthatrequiresamultidisciplinaryapproach.TheuseofZDDPasalubricantadditiveprovidesavaluabletoolforinvestigatinghowthechemicalandphysicalpropertiesofmaterialsaffecttheirfrictionandwearbehavior.Byunderstandingthesemechanisms,researcherscandevelopnewapproachesforcontrollingandminimizingwear,leadingtomoredurableandefficientmaterials.

Moreover,thestudyofZDDPcanalsoaidindevelopingnewsurfaceengineeringtechniquestoenhancethetribologicalpropertiesofmaterials.Forexample,theincorporationofZDDPintocoatingsorcompositematerialscouldimprovetheirwearresistanceandreducefriction,expandingtheirpotentialapplicationinavarietyofindustries.

Finally,theuseofZDDPasalubricantadditivecanalsodriveinnovationinthefieldofmaterialscharacterization,includingthedevelopmentofnovelanalyticaltechniquesformeasuringcontactpressuresandsurfaceinteractions.Theseadvancementscouldhaveimplicationsbeyondthetribologyandlubricationfields,contributingtobroadereffortstounderstandmaterialbehaviorandperformance.

Insummary,thestudyofZDDPanditstribologicalpropertieshasthepotentialtoimpactmaterialsengineeringatmultiplelevels,fromenhancingtheefficiencyandsustainabilityoflubricationtoadvancingourunderstandingoffrictionandwearmechanisms.Continuedresearchinthisareaholdspromisefordevelopingnewmaterialsandtechnologiesthatcanrevolutionizeawiderangeofindustries.OneareawhereZDDPhasshownparticularpromiseisinthedevelopmentofmoresustainablelubricants.Lubricationisessentialfortheefficientoperationofawiderangeofindustrialmachinery,fromenginesandgearstobearingsandpumps.However,traditionallubricantscanbeenvironmentallydamagingandcontributetoclimatechangethroughthereleaseofgreenhousegases.

Bycontrast,ZDDP-basedlubricantshavebeenfoundtohavealowerenvironmentalimpactthanmanyconventionaloptions.Forexample,becauseZDDPcanimprovelubricationefficiencyandreducetheamountoffrictionbetweenmovingsurfaces,itcanleadtosavingsinenergyusageandareducedcarbonfootprint.Additionally,becauseZDDPisderivedfromnaturalsourcessuchaszincandphosphorous,itisconsideredtobeamoresustainableoptionthansomesyntheticlubricantsthatrelyonfossilfuelsorothernon-renewableresources.

AnotherareawhereZDDPresearchismakinganimpactisinthe