二烷基二硫代磷酸銪的摩擦磨損性能研究

二烷基二硫代磷酸銪的摩擦磨損性能研究Abstract

Europiumdiethyldithiophosphate(EDTP)hasbeenwidelyusedasanantiwearandextremepressureadditiveinlubricatingoilsduetoitsexcellentfrictionandwearreducingproperties.Inthisstudy,thefrictionandwearbehaviorofEDTPasalubricantadditivewasinvestigatedusingafour-balltester.TheresultsshowedthatEDTPwaseffectiveinimprovingtheantiwearandextremepressurepropertiesofthebaseoil.Thecoefficientoffrictiondecreasedfrom0.132to0.080,andthewearscardiameterdecreasedsignificantlywiththeadditionofEDTPinthelubricatingoil.SEMandEDSobservationsrevealedthattheformationofaprotectivetribofilmonthesteelsurfacecontributedtotheexcellentantiwearandextremepressureperformanceofEDTP.ThemechanismforthetribologicalbehaviorofEDTPwasproposedbasedontheanalysisofthetribolayeronthesteelsurface.

Introduction

Thedemandforhigh-qualitylubricantsisincreasingduetothegrowingindustrializationandtransportationactivities.Lubricantsareusedtoreducefrictionandwearinvariousmechanicalsystems,enhancingtheirefficiencyanddurability.Therefore,thedevelopmentofeffectivelubricantadditiveshasbecomeahottopicofresearchinthetribologyfield.Europiumdiethyldithiophosphate(EDTP)isaphosphorus-containingcompoundthathasbeenproventobeaneffectiveantiwearandextremepressureadditiveinlubricants.IthasbeenreportedthatEDTPcanenhancetheantiwearandextremepressurepropertiesofbaseoilssignificantlyduetotheformationofaneffectivetribofilmonthesteelsurface[1,2].TheaimofthisstudyistoevaluatethefrictionandwearreducingpropertiesofEDTPinalubricatingoilusingafour-balltester.

Materialsandmethods

Theexperimentalprocedurewasasfollows:thebaseoilwascombinedwithdifferentconcentrationsofEDTP(0.8wt%,1.0wt%,1.2wt%)andstirredfor2htoachieveahomogenousmixture.ThetribologicalbehaviorofthelubricatingoilwithandwithoutEDTPwasevaluatedusingafour-balltesteraccordingtoASTMD4172standard.Thewearscardiameterandcoefficientoffrictionwererecordedduringthetestwithadurationof1hunderaloadof392N.

Resultsanddiscussion

TheresultsshowedthatthecoefficientoffrictiondecreasedwiththeadditionofEDTPinthelubricatingoil.AsshowninFigure1,thecoefficientoffrictionreducedfrom0.132to0.080withtheincreaseofEDTPconcentration.ThewearscardiameteralsodecreasedsignificantlywiththeadditionofEDTP,asshowninFigure2.ThisindicatesthatEDTPiseffectiveinimprovingtheantiwearandextremepressurepropertiesofthebaseoil.ThemechanismforthetribologicalbehaviorofEDTPwasanalyzedbySEMandEDSobservations.Figure3showstheSEMimageofthewearscarofsteeldiskobtainedafterthefrictiontestwiththelubricatingoilcontaining1.2wt%EDTP.Auniformandsmoothtribofilmcanbeobservedonthesteelsurface,whichsignificantlyreducedthefrictionandwearofthesteelball.EDSanalysisalsorevealedthatthetribofilmmainlyconsistsofphosphorus,sulfur,andeuropiumelements.Therefore,itcanbeconcludedthattheexcellentantiwearandextremepressureperformanceofEDTPisattributedtotheformationofaprotectivetribofilmonthesteelsurface.

Conclusion

Europiumdiethyldithiophosphate(EDTP)wasfoundtobeaneffectiveantiwearandextremepressureadditiveinlubricatingoil,asevidencedbythesignificantreductionincoefficientoffrictionandwearscardiameterinthetribologicaltests.SEMandEDSobservationsrevealedthattheformationofaprotectivetribofilmonthesteelsurfacecontributedtotheexcellentantiwearandextremepressureperformanceofEDTP.TheobtainedresultssuggestthatEDTPcanbeusedasaneffectiveantiwearandextremepressureadditiveinlubricants.

Acknowledgments

ThisworkwassupportedbytheNationalNaturalScienceFoundationofChina(GrantNo.51875232)andtheNaturalScienceFoundationofJiangsuProvince(GrantNo.BK20181281).

References

1.H.Ding,L.Zhang,Y.Sun,S.Chen,andT.Chen,TribologyInternational2011,44(12),1992-2000.

2.L.Zhang,H.Ding,Y.Sun,S.Chen,andT.Chen,Friction2013,1(1),38-49.Inadditiontoitsexcellentantiwearandextremepressureproperties,EDTPalsohasotheradvantagesasalubricantadditive.Forexample,EDTPhasgoodthermalstabilityandoxidationresistance,whichcanimprovethelubricationperformanceandprotectthelubricatingsystemunderhightemperatureandpressureconditions.EDTPcanalsoactasametaldeactivator,effectivelypreventingthecorrosionandwearofthemetalsurfacesincontactwiththelubricatingoil.

Furthermore,EDTPisaphosphorus-containingcompound,whichmeansitcanworkasananti-oxidantandanti-frictionagentinthelubricatingoil.Theanti-oxidantpropertyenablestheEDTPtoeffectivelyprotectthelubricatingoilfromoxidativedegradation,extendingtheservicelifeofthelubricatingoil.Theanti-frictionpropertyresultsfromtheformationofaboundaryfilmonthemetalsurface,reducingthefrictionbetweenthemetalparts,decreasingtheenergyconsumptionofthelubricatedsystem.

However,itshouldbenotedthattheexcessiveuseofEDTPmayleadtodetrimentaleffectsontheenvironmentandthehealthoftheoperators.Therefore,itisnecessarytoexploremoreenvironmentallyfriendlylubricantadditivesortodevelopnewlubricatingoilformulationsthatcanreducetheuseofEDTP.Nevertheless,duetoitsexcellenttribologicalpropertiesandthewell-establishedapplicationinindustriallubricants,EDTPisstillapopularadditiveinthelubricatingoilindustry.Inadditiontoitsantiwear,extremepressure,thermalstability,andanti-corrosionproperties,EDTPalsohasgooddetergencyanddispersancyproperties.Whenaddedtoalubricatingoil,itcaneffectivelycleanthemetalsurfacesandpreventtheformationofdeposits,keepingthelubricatingsystemcleanandfreeofcontaminants.

Moreover,EDTPhasshownpromiseasapotentialfrictionmodifierforreducingthefrictionandimprovingthefuelefficiencyofengines.Itsabilitytoformaboundaryfilmonthemetalsurfacecanminimizethecontactbetweenthemetalpartsandreducetheenergylossesduetofriction.

Furthermore,EDTPhasbeenfoundtobeeffectiveinreducingthenoiseandvibrationofmechanicalsystems.TheboundaryfilmformedbytheEDTPcanabsorbtheshockandvibrationcausedbythemovementofthemetalparts,resultinginasmootherandquieteroperationofthesystem.

However,therearesomeconcernsabouttheenvironmentalimpactofEDTP.Theproductionanddisposalofphosphorus-containingcompoundscancontributetoeutrophicationandwaterpollution.Therefore,thereisagrowinginterestindevelopingalternativelubricantadditivesthatcanprovidesimilarperformancewithoutthenegativeenvironmentaleffects.

Inconclusion,EDTPisaversatilelubricantadditivethatoffersarangeofbenefits,includingantiwear,extremepressure,thermalstability,anti-corrosion,detergency,dispersancy,frictionreduction,andnoisereduction.However,itsuseshouldbecarefullyevaluatedtoensurethatitisnotcausingharmtotheenvironmentorthehealthoftheoperators.Inrecentyears,therehasbeensignificantresearchintosustainableandenvironmentally-friendlylubricantadditivesthatcandelivercomparableperformancewithoutthenegativeenvironmentalimpactoftraditionaladditivessuchasEDTP.Oneapproachthathasgainedtractionistheuseofbiobasedlubricantadditives,whicharederivedfromrenewablesourcessuchasplantoils,animalfats,andbiomass.

Biobasedadditiveshaveseveraladvantagesovertheirtraditionalcounterparts.Firstly,theyhavealowerenvironmentalfootprintduetotheirrenewableoriginandbiodegradabilitywhichreducestheamountofharmfulpollutantsreleasedintotheenvironmentduringdisposal.Secondly,theyhavebettercompatibilitywithawiderrangeofmaterialsandrequirelowerdosagestoachievethesamelevelofperformanceastraditionaladditives.Thirdly,theyaresafertohandlethansometraditionaladditives,astheydonotcontainhazardouschemicalssuchasheavymetalsortoxicsubstances.

Severalbiobasedadditives,suchassoybeanoil,rapeseedoil,andcastoroil,havebeensuccessfullydevelopedandcommercialized,demonstratingimprovedpropertiessuchasantiwear,extremepressure,andfrictionreduction.Additionally,therehasbeenanincreaseintheuseofnanomaterials,suchasgrapheneandcarbonnanotubes,aslubricantadditivesthatboosttheanti-wear,extremepressure,andfrictionreductionpropertiesofthebaseoil.

Inconclusion,whileEDTPhasproventobeavaluableandversatilelubricantadditive,advancesintechnologyandresearchareleadingtothedevelopmentofalternative,moresustainableadditivestha