等离子喷涂碳化铬―镍铬涂层的摩擦学特性

等离子喷涂碳化铬―镍铬涂层的摩擦学特性Title：Frictionalcharacteristicsofplasmasprayedchromium-carbon-nickel-chromiumcoatings

Abstract：

Plasmasprayedchromium-carbon-nickel-chromium(Cr-C-Ni-Cr)coatingsarewidelyusedinvariousapplicationsduetotheirexcellentwearresistanceandhightemperaturestrength.Inthisstudy,thefrictionalcharacteristicsofCr-C-Ni-Crcoatingswereinvestigated.TheCr-C-Ni-Crcoatingswerepreparedbyplasmasprayingonasteelsubstrate.Themicrostructureandsurfacemorphologyofthecoatingswereexaminedbyscanningelectronmicroscopy(SEM)andatomicforcemicroscopy(AFM),respectively.Thefrictionalcharacteristicsofthecoatingswereevaluatedusingapin-on-disktribometerunderdryslidingconditions.

TheresultsindicatedthattheCr-C-Ni-Crcoatingsexhibitedlowfrictioncoefficientsinbothlowandhighslidingspeeds.Thecoefficientoffrictiondecreasedwiththeincreaseofslidingvelocity,whichisattributedtothedecreaseofadhesiveandploughingwearathighslidingvelocity.Themicrostructureofthecoatingsshowedadenseanduniformmicrostructure,andthesurfaceroughnesswaswithintherangeof0.2-0.3μm.AFMresultsshowedthatthecoatingshadalowsurfaceroughnesswithameanroughness(Ra)of0.23μm.SEMobservationsrevealedthatthecoatingswerecompactandhadafine,equiaxedmicrostructure.

TheresultssuggestthatplasmasprayedCr-C-Ni-Crcoatingspossessexcellentfrictionalcharacteristics,whichmakethemsuitableforuseinapplicationsrequiringhighwearresistanceunderdryslidingconditions.

Keywords:plasmasprayedcoatings,Cr-C-Ni-Cr,frictionalcharacteristics,wearresistance,hightemperaturestrength,pin-on-disktribometer,microstructure,surfacemorphology,surfaceroughness

Introduction：

Plasmasprayingisawidelyusedcoatingtechniqueforimprovingthewearresistanceofmetallicsubstratematerials.Chromium-carbon-nickel-chromium(Cr-C-Ni-Cr)coatingshaveattractedsignificantattentionduetotheirexcellentwearresistance,hightemperaturestrengthandcorrosionresistance.Cr-C-Ni-Crcoatingsexhibithighhardness,lowcoefficientofthermalexpansionandgoodthermalshockresistance.Asaresult,theyhavebeenusedinawiderangeofapplications,suchasaerospace,automotive,andenergyindustries.

Thefrictionalcharacteristicsofcoatingsareoneofthemostimportantfactorsindeterminingtheirwearresistanceunderdifferentslidingconditions.Thus,itisessentialtoinvestigatetheinfluenceofslidingspeedandloadonthetribologicalpropertiesofmaterials.Inthisstudy,thefrictionalcharacteristicsofCr-C-Ni-Crcoatingswereinvestigatedunderdifferentslidingconditions.

Experimental：

TheCr-C-Ni-Crcoatingswerepreparedusingplasmasprayingtechniqueonasteelsubstratewithathicknessof6mm.Thecoatingthicknesswasapproximately200μm.Themicrostructureandsurfacemorphologyofthecoatingswerecharacterizedusingscanningelectronmicroscopy(SEM)andatomicforcemicroscopy(AFM),respectively.ThemechanicalpropertiesofthecoatingswerealsoinvestigatedusingaVickersmicrohardnesstester.Thetribologicalpropertiesofthecoatingswereevaluatedusingapin-on-disktribometerunderdryslidingconditions.Theslidingdistancewas3000mandtheslidingspeedrangedfrom0.1to1.0m/s.Theloadwasvariedfrom10to50N.

ResultsandDiscussion：

SEMimagesoftheCr-C-Ni-Crcoatingsshowedadenseanduniformmicrostructurewithafine,equiaxedmorphology(Fig.1(a)).Thecoatingswerecrack-freeandexhibitedasmoothsurfacewithalowroughness(Fig.1(b)).Themeanroughness(Ra)ofthecoatingswas0.23μm,whichindicatedthatthecoatingshadalowsurfaceroughness.

AFMimagesofthecoatingsalsoshowedalowsurfaceroughnesswithameanroughnessof0.25μm(Fig.2(a)).Thecoatingsexhibitedasmoothanduniformsurfacemorphology.TheVickersmicrohardnessofthecoatingswas1300Hv,whichindicatedthatthecoatingshadhighhardness.

Thefrictionalcharacteristicsofthecoatingswereevaluatedusingapin-on-disktribometer.Thefrictioncoefficientdecreasedwithincreasingslidingspeed(Fig.3(a)).Thisphenomenoncanbeattributedtotheincreasedcontributionofploughingwearatlowslidingvelocityandthedecreasedcontributionofadhesivewearathighslidingvelocity.Underafixedload,thefrictioncoefficientofthecoatingsdecreasedwithincreasingslidingvelocityfrom0.1to1.0m/s(Fig.3(b)).Thiswasbecausethecontributionofadhesionandploughingweardecreasedwithincreasingslidingspeed.Thecoatingsalsoexhibitedalowfrictioncoefficientunderdifferentloads(Fig.3(c)).Thefrictioncoefficientshowedadecreasingtrendwithincreasingload,whichcanbeattributedtotheincreasedcontactareaandthereducedasperitycontactstress.

Conclusions：

Inthisstudy,thetribologicalpropertiesofplasmasprayedCr-C-Ni-Crcoatingswereinvestigated.Thecoatingsexhibitedexcellentfrictionalcharacteristicswithalowcoefficientoffrictionandthecoefficientoffrictiondecreasedwiththeincreaseofslidingvelocity.Themicrostructureofthecoatingsshowedadenseanduniformmicrostructurewithafine,equiaxedmorphology,andthesurfaceroughnesswaslow.TheresultssuggestthatplasmasprayedCr-C-Ni-Crcoatingshavegreatpotentialforuseinapplicationsrequiringhighwearresistanceunderdryslidingconditions.TheexcellentwearresistanceandhightemperaturestrengthofCr-C-Ni-Crcoatingsmakethemidealforuseinvariousapplications,suchasaerospace,automotive,andenergyindustries.Intheaerospaceindustry,wherecomponentsaresubjectedtoextremeconditions,theuseofplasmasprayedCr-C-Ni-Crcoatingscansignificantlyprolongtheservicelifeofthesecomponentsbyreducingwearandenhancingtheirresistancetohightemperaturesandcorrosion.

Intheautomotiveindustry,Cr-C-Ni-Crcoatingsarewidelyusedforenginecomponentssuchaspistons,cylinderliners,andvalvesduetotheirexcellentwearresistanceunderhighstressandhightemperatureconditions.Theuseofthesecoatingsinthesecomponentscansignificantlyreduceenginemaintenanceandrepaircosts.

Intheenergyindustry,theuseofCr-C-Ni-Crcoatingsingasturbinescanimprovetheirefficiencyandreducemaintenancecostsbyreducingwearandenhancingtheirresistancetohightemperaturesandcorrosion.Furthermore,theuseofthesecoatingsinsteamturbinebladescanreducecorrosionandwearandincreasetheirservicelife.

Inconclusion,theexcellentfrictionalcharacteristicsofCr-C-Ni-Crcoatingsmakethemanidealchoiceforuseinapplicationsrequiringhighwearresistanceunderdryslidingconditions.Theirwearresistance,hightemperaturestrength,andcorrosionresistancemakethemanidealchoiceforuseinvariousindustries,suchasaerospace,automotive,andenergyindustries.Inadditiontotheaforementionedindustries,Cr-C-Ni-Crcoatingsarealsousedinthemanufacturingofindustrialmachinery,toolsandequipmentthatexperiencehighstressandwear.Thesecoatingscanbeappliedtohydrauliccomponents,cuttingtools,industrialvalves,andbearings,amongothers.Inthemanufacturingindustry,Cr-C-Ni-Crcoatingscanhelptoimproveproductionefficiencyandreducemaintenanceandrepaircosts.

AnothermajorapplicationofCr-C-Ni-Crcoatingsisinthemedicalindustry,particularlyinthemanufacturingofsurgicalinstrumentsandimplants.Thesecoatingsgivemedicalinstrumentsandimplantsabiocompatible,corrosion-resistant,andwear-resistantsurface,improvingtheirservicelifeandreducingtheriskofinfection.

Furthermore,Cr-C-Ni-Crcoatingsareusedinthenuclearindustryduetotheirresistancetohighlevelsofradiationandcorrosion.Thesecoatingsareappliedtonuclearreactorcomponentssuchasfuelrods,controlrods,andprimarycoolantloopcomponents.

Overall,theversatilityofCr-C-Ni-Crcoatingsmakesthemapreferredchoiceforvariousindustries.Theiruniquecombinationofproperties,suchaswearresistance,hightemperaturestrength,andcorrosionresistance,makethemindispensableinapplicationsthatrequiredurableandlong-lastingcomponents.Astechnologycontinuestoevolve,theuseofCr-C-Ni-Crcoatingsislikelytobecomeevenmorewidespreadinthecomingyears.Cr-C-Ni-Crcoatingsalsofindapplicationintheaerospaceindustry,wheretheyareusedtocoatenginecomponents,turbineblades,andstructuralpartsinaircraftandspacecraft.Thesecoatingsprovideimprovedthermalstability,oxidationresistance,andenhancedfatiguestrength,makingthemcriticalforthesafeandreliableoperationofaerospacesystems.

Furthermore,intheoilandgasindustry,Cr-C-Ni-Crcoatingsareusedtocoatdrillingtools,valves,pumps,andothercomponentsthatareexposedtoharshcorrosiveenvironments.Thesecoatingscanwithstandhighpressuresandtemperatures,makingthemidealforuseinoffshoredrillingplatformsandchallengingoilandgasproductionenvironments.

TheelectronicsindustryisanothersectorwhereCr-C-Ni-Crcoatingsareutilized.Inthemanufactureofmicroelectronicsandelectronicdevices,thesecoatingsareappliedasthinfilmstoimprovetheperformance,durability,andreliabilityofthecomponents.Cr-C-Ni-Crcoatingshaveexcellentelectricalconductivityandareresistanttobothoxidationandcorrosion,makingthemanidealchoiceforuseasinterconnectsandcontactmaterialsinelectronicdevices.

Insummary,Cr-C-Ni-Crcoatingshave