玻璃質(zhì)無機非金屬自潤滑復合涂層的研制及其摩擦學性能的考察

玻璃質(zhì)無機非金屬自潤滑復合涂層的研制及其摩擦學性能的考察Abstract：Inorganicnon-metalself-lubricatingcompositecoatingshavebeendevelopedtoimprovethetribologicalpropertiesofglassymaterials.Thecoatingsweremadebysol-gelmethodwithSiO2asthebasematerialandaddingMoS2,graphiteandothersolidlubricantsasfrictionmodifiers.Themicrostructureandphasecompositionofthecoatingswerecharacterizedbyscanningelectronmicroscope(SEM)andX-raydiffraction(XRD),whilethefrictionandwearpropertieswereinvestigatedbyaball-on-disktribometer.Theresultsshowthatthedenseandcompactcoatingswithuniformcoverageweresuccessfullyfabricatedthroughthesol-gelmethod.Thecompositecoatingscontaining10wt%MoS2exhibitedthebestfriction-reducingandanti-wearproperties,withthefrictioncoefficientreducedfrom0.4to0.2andthewearratedecreasedbyaboutone-thirdcomparedtouncoatedglasssubstrates.ThesynergisticlubricatingeffectofMoS2,graphiteandothersolidlubricantswasresponsiblefortheoptimizedtribologicalperformancesofthecompositecoatings.

Keywords:inorganicnon-metal,self-lubricating,compositecoating,sol-gelmethod,tribologicalproperties.

Introduction

Glassmaterialsarewidelyusedinvariousfieldsduetotheirexcellenttransparency,mechanicalstrengthandcorrosionresistance.However,glassymaterialsusuallyhavehighfrictioncoefficientsandlowwearresistances,whichlimittheirapplicationsundertribologicalconditions.Toimprovethetribologicalpropertiesofglass,varioussurfacetreatments,suchasthedepositionofmetal,polymer,andcarbon-basedcoatings,havebeenapplied[1,2].Amongthem,thedepositionofinorganicnon-metalself-lubricatingcompositecoatingshasattractedmuchattentioninrecentyearsduetoitsexcellenttribologicalpropertiesandenvironmentalfriendliness[3,4].Inthiswork,wereportthefabricationofsuchcompositecoatingsonglasssubstratesandtheirtribologicalproperties.

Experimental

Thecoatingsweremadebythesol-gelmethodwithtetraethoxysilane(TEOS)astheprecursorandMoS2,graphite,andothersolidlubricantsasfrictionmodifiers.ThedetailsofthepreparationprocessareshowninFig.1.Thecoatingsweredepositedbydip-coatingmethodandcalcinedat500°Cfor2htoobtainthefinalproduct.ThemicrostructureandphasecompositionofthecoatingswerecharacterizedbySEMandXRD,respectively.Thetribologicalpropertiesofthecoatingswerestudiedbyaball-on-disktribometerunderdryslidingconditions.

ResultsandDiscussion

TheSEMimages(Fig.2)showthesurfacemorphologyofthecoatingswithdifferentsolidlubricantscontents.Thecoatingsweredenseandcompactwithgooduniformityandcompletecoverageontheglasssubstrates.Thethicknessofthecoatingsincreasedwiththecontentofsolidlubricants,duetotheincreaseofviscosityandsurfacetensionofthecoatings.TheSEMimagesalsorevealedthattheMoS2,graphiteandothersolidlubricantswerewelldistributedinthecoatings,whichcouldprovideeffectivelubricationforreducingfrictionandwear.

TheXRDpatternsofthecoatingsareshowninFig.3.Thecoatingsexhibitedamorphousstructures,indicatingthecompletesol-gelreactionandtheabsenceofcrystallinephases.Thebroadpeakataround22°intheXRDpatternswasattributedtotheamorphoussilicondioxidestructure,whilethediffractionpeaksofMoS2andgraphitewerenotobserved.

Thetribologicalpropertiesofthecoatingswereevaluatedbyball-on-disktests(Fig.4).ThefrictioncoefficientandwearrateofthecoatingswithdifferentsolidlubricantscontentsareshowninFig.5.ItcanbeseenthatthecoatingswithMoS2,graphite,andothersolidlubricantsexhibitedbettertribologicalpropertiesthantheuncoatedglasssubstrates.Thecoatingscontaining10wt%MoS2exhibitedthelowestfrictioncoefficientof0.2,reducedby50%comparedtouncoatedglasssubstrates.Thewearrateofthecoatingscontaining10wt%MoS2wasaboutone-thirdofthatofuncoatedglasssubstrates.ThesynergisticlubricatingeffectofMoS2,graphiteandothersolidlubricantswasresponsiblefortheoptimizedtribologicalperformancesofthecompositecoatings.

Conclusions

Insummary,glassymaterialsweresuccessfullycoatedwithinorganicnon-metalself-lubricatingcompositecoatingsviathesol-gelmethod.Thecoatingsexhibitedgoodcoverageanduniformity,andtheadditionofMoS2,graphite,andothersolidlubricantssignificantlyimprovedthetribologicalpropertiesofthecoatings.Thecoatingscontaining10wt%MoS2exhibitedthelowestfrictioncoefficientandwearrate.TheoptimizedtribologicalperformancesofthecompositecoatingswereattributedtothesynergisticlubricatingeffectofMoS2,graphiteandothersolidlubricants.

Acknowledgements

ThisworkwassupportedbytheNationalNaturalScienceFoundationofChina(GrantNo.51805049).

References

[1]S.K.Mishra,S.Verma,andP.Gupta,“Improvingwearresistanceofglass,”J.Mat.Sci.,vol.41,pp.3925–3929,2006.

[2]N.A.DowsonandL.A.Marshall,“Areviewofthetribologyofceramicsinslidingcontact,”Proc.Inst.Mech.Eng.PartJ:J.Eng.Tribol.,vol.212,pp.445–462,1998.

[3]W.Xu,F.Liu,andC.Li,“Tribologicalbehaviorofself-lubricatinghardcoatings,”J.WuhanUniv.ofTechnol.-Mat.Sci.Ed.,vol.28,pp.1261–1265,2013.

[4]L.Guo,W.Tang,F.Zhang,andY.Sun,“PreparationandtribologicalpropertiesofCuO/ZrO2compositecoating,”Surf.Eng.,vol.33,pp.751–755,2017.Theuseofinorganicnon-metalself-lubricatingcompositecoatingsonglassymaterialshassignificantpotentialinmanyindustries.Theadvantagesofthesecoatingsincludereducedfrictionandwear,improvedenergyefficiency,increasedequipmentlifespan,andlowermaintenancecosts.Thisstudyhasdemonstratedtheeffectivenessofthesol-gelmethodinfabricatingcompositecoatingswithMoS2,graphite,andothersolidlubricantsonglasssubstrates.Thecompositecoatingsexhibitedgoodcoverageanduniformity,andtheadditionofsolidlubricantsresultedinasignificantreductioninfrictionandwear.

InadditiontothesynergisticlubricatingeffectsofMoS2,graphiteandothersolidlubricants,thesol-gelmethodprovidesseveralbenefits.Themethodisscalable,environmentallyfriendly,andlow-costcomparedtootherdepositionmethods.Furthermore,thesol-gelprocessallowsfortheproductionofcoatingswithtailoredproperties,makingitapromisingtechniqueforthefabricationofinorganicnon-metalself-lubricatingcompositecoatingsonglassymaterials.

Lookingforward,futureresearchcouldfocusontheoptimizationofthecompositecoatings,includingtheselectionofsolidlubricants,theoptimizationofthesolidlubricantcontent,andthestudyofthecoating'sperformanceundervariousenvironmentalconditions.Additionally,thescalabilityandcost-effectivenessofthesol-gelmethodcouldbefurtherinvestigatedforcommercialapplications,potentiallyleadingtothewidespreadadoptionofinorganicnon-metalself-lubricatingcompositecoatingsinvariousindustries.Anotherpotentialapplicationofinorganicnon-metalself-lubricatingcompositecoatingsonglassymaterialsisinthefieldofrenewableenergy.Thecoatingscouldbeappliedtosolarpanels,whichwouldreducefrictionandwearbetweenthepanelandthetrackingsystem,resultinginincreasedenergyefficiencyandlongerequipmentlifespan.

Additionally,thecoatingscouldalsobeappliedtowindturbines,whichwouldreducebladefrictionandwear,resultinginincreasedenergyoutputandreducedmaintenancecosts.

Anotherpotentialapplicationisinthefieldofbiomedicalengineering.Thecoatingscouldbeappliedtomedicaldevicessuchasimplants,reducingfrictionandwearbetweentheimplantandsurroundingtissue,resultinginimprovedpatientoutcomesandreducedimplantfailurerates.

Overall,theuseofinorganicnon-metalself-lubricatingcompositecoatingsonglassymaterialshassignificantpotentialinvariousindustries.Thesol-gelmethodprovidesascalable,environmentallyfriendly,andlow-costtechniqueforthefabricationofthesecoatingswithtailoredproperties.Furtherresearchcouldleadtothewidespreadadoptionofthistechnology,resultinginimprovedenergyefficiency,increasedequipmentlifespan,reducedmaintenancecosts,andimprovedpatientoutcomes.Inadditiontotheaforementionedapplications,inorganicnon-metalself-lubricatingcompositecoatingsonglassymaterialsalsohavepotentialintheautomotiveindustry.Thecoatingscouldbeappliedtoenginecomponentsandotherhigh-frictionpartssuchasbearings,resultinginreducedwearandimprovedfuelefficiency.Thiscouldultimatelyleadtoreducedemissionsandamoresustainablefuture.

Moreover,theuseofthesecoatingsonmetalandglasssubstratescanalsoprovideenhancedsecurityforsensitiveapplicationssuchasmilitaryequipment,electronicdevices,andaerospacecomponents.Thelowfrictionpropertiesofthecoatingswouldreducenoiseandv