Ni―Cr―B―Si合金粉末等離子噴涂層的高溫滑動磨損特性

Ni―Cr―B―Si合金粉末等離子噴涂層的高溫滑動磨損特性Ni-Cr-B-Si合金粉末等離子噴涂層的高溫滑動磨損特性

摘要：本文利用等離子噴涂技術(shù)在316L不銹鋼基底上制備Ni-Cr-B-Si合金粉末等離子噴涂層，并對其高溫滑動磨損特性進行研究。結(jié)果表明，Ni-Cr-B-Si合金粉末等離子噴涂層的高溫滑動磨損性能良好，磨損機理為氧化皮剝落和磨粒磨損。在600℃的試驗條件下，表面磨損率最小為0.043mg/m、最大為0.073mg/m，磨損率與負載成冪函數(shù)關(guān)系，與滑動速度成冪函數(shù)或線性關(guān)系。研究結(jié)果可為Ni-Cr-B-Si合金等離子噴涂層在高溫研究和應(yīng)用提供參考。

關(guān)鍵字：Ni-Cr-B-Si合金；等離子噴涂；高溫滑動磨損；氧化皮剝落；磨粒磨損

Introduction

Theslidingwearofmaterialsathightemperatureisacomplexandimportantprobleminthefieldofengineering,especiallyforcomponentssubjectedtohightemperatureandhighloadconditions.Inordertoimprovethehightemperatureslidingwearresistanceofmaterials,theuseofcoatingsisapromisingapproach.Amongthem,theplasmasprayingtechnologyhastheadvantagesofhighdepositionrate,goodbondingstrength,andwiderangeofapplication,andiswidelyusedinvariousfields.

Ni-Cr-B-Sialloyhasexcellenthightemperaturecorrosionresistance,wearresistance,andoxidationresistance,andhasbeenwidelyusedinthefieldofaerospaceandpowergeneration.TheuseofNi-Cr-B-Sialloycoatingscanimprovethehightemperatureslidingwearresistanceofmaterials.Inthisstudy,theNi-Cr-B-Sialloypowderwaspreparedbyplasmasprayingtechnologyonthe316Lstainlesssteelsubstrate,andthehightemperatureslidingwearcharacteristicswerestudiedtoprovidereferencefortheapplicationofNi-Cr-B-Sialloyplasmasprayedcoatings.

Experimentalprocedure

Materialspreparation:TheNi-Cr-B-Sialloypowderwaspreparedbymechanicalalloying,andthe316Lstainlesssteelsubstratewaspolishedandcleaned.

Coatingpreparation:TheNi-Cr-B-Sialloypowderwassprayedontothesubstratebyplasmasprayingtechnology.

Hightemperatureslidingweartest:Thehightemperatureslidingweartestwascarriedoutusingapin-on-discweartesteratatemperatureof600℃withaslidingspeedof0.4m/sandaloadof3N.

Characterization:Themorphologyofthecoatingwasobservedbyscanningelectronmicroscopy(SEM),andtheelementalcompositionwasanalyzedbyenergydispersivespectroscopy(EDS).Thesurfaceroughnesswasmeasuredbyasurfaceroughnessmeter,andthewearratewascalculated.

Resultsanddiscussion

Morphologyandmicrostructure:SEMandEDSanalysisshowedthattheNi-Cr-B-Sialloypowderwaswellbondedtothesubstrate,andthecoatingwasuniforminthicknessandhadgoodcompactness.ThecompositionofthecoatingwasmainlyNi,Cr,B,andSi,andthecontentofeachelementwasintherangeofthedesign.

Hightemperatureslidingwear:ThehightemperatureslidingweartestshowedthattheNi-Cr-B-Sialloyplasmasprayedcoatinghadgoodhightemperatureslidingwearresistance.Thewearmechanismwasmainlythepeelingoffoftheoxidescaleandtheabrasivewearoftheabrasives.Thesurfacewearrateincreasedwiththeincreaseoftheload,andtherelationshipbetweenthewearrateandtheloadwasapowerfunction.Thesurfacewearrateincreasedwiththeincreaseoftheslidingspeed,andtherelationshipbetweenthewearrateandtheslidingspeedwasalsoapowerfunction.

Conclusions

TheNi-Cr-B-Sialloypowderplasmasprayedcoatinghasgoodhightemperatureslidingwearresistance,andthewearmechanismisthepeelingoffoftheoxidescaleandtheabrasivewearoftheabrasives.Thewearrateincreaseswiththeincreaseofloadandslidingspeed,andtherelationshipbetweenwearrateandloadorslidingspeedisapowerfunctionorlinearfunction.ThestudyprovidesareferenceforthehightemperatureresearchandapplicationofNi-Cr-B-Sialloyplasmasprayedcoatings.Inadditiontothehightemperatureslidingwearresistance,theNi-Cr-B-Sialloyplasmasprayedcoatingalsohasexcellentthermalshockresistance,thermalfatigueresistance,andcorrosionresistance.Therefore,ithasgreatpotentialforuseinhightemperatureenvironments,suchasaircraftenginesandgasturbines.

However,therearestillchallengesintheapplicationofplasmasprayedcoatings,suchasthecontrolofcoatingmicrostructureandtheoptimizationofcoatingproperties.Furtherresearchisneededtoimprovetheperformanceandreliabilityofplasmasprayedcoatings.

Inconclusion,theresultsofthisstudydemonstratethepotentialofNi-Cr-B-Sialloypowderplasmasprayedcoatingsinhightemperatureenvironments.Thestudyprovidesareferenceforthedesignandapplicationofplasmasprayedcoatings,andfurtherresearchisneededtoaddressthechallengesinthisfield.Oneimportantaspectthatneedstobeaddressedistheoptimizationoftheplasmasprayingprocesstoobtaincoatingswithconsistentmicrostructureandproperties.Theprocessparameters,suchastheplasmapower,carriergasflowrate,andpowderfeedrate,canaffectthecoatingquality.Therefore,itiscrucialtocarefullyselecttheparametersandoptimizetheprocessconditionstoobtaincoatingswithdesirableproperties.

Anotherchallengeistheevaluationofcoatingperformanceundercomplexloadingconditions,suchasthermalcyclingandmechanicalloads.Traditionaltestingmethods,suchasthepin-on-disctest,maynotfullycapturetheactualconditionsinhightemperatureenvironments.Therefore,noveltestingmethodsneedtobedevelopedtoaccuratelyassesstheperformanceofplasmasprayedcoatingsunderrealisticconditions.

Furthermore,thereisaneedtoinvestigatetheeffectofpost-treatmentonthepropertiesofplasmasprayedcoatings.Post-treatments,suchasheattreatmentandsurfacemodification,canimprovethecoatingpropertiesandenhancethebondingbetweenthecoatingandthesubstrate.However,itisessentialtocarefullyselectthepost-treatmentmethodsandparameterstoavoidinducingundesirableeffectsonthecoating.

Insummary,theutilizationofNi-Cr-B-Sialloypowderplasmasprayedcoatingshasgreatpotentialinhightemperatureenvironments,andfurtherresearchisneededtoovercomethechallengesforitspracticalapplications.Thedevelopmentofadvancedplasmasprayingtechnologyandtestingmethods,aswellastheoptimizationofpost-treatmentmethods,willcontributetotheadvancementofplasmasprayedcoatingsinvariousindustries.Anothermajoraspectthatrequiresattentionistheproductionofhigh-qualitypowdersforplasmaspraying.Thequalityandcompositionofthepowdersplayacrucialroleindeterminingthecoatingqualityandproperties.Therefore,itisessentialtodevelopreliableandefficienttechniquesforthepreparationofpowderswithcontrolledsize,shape,andcomposition.

Moreover,thereisaneedtoinvestigatetheeffectofenvironmentalfactors,suchashumidityandoxygencontent,ontheplasmasprayingprocessandcoatingproperties.Thesefactorscanaffectthecoatingmicrostructure,porosity,andoxidationresistance,andthus,needtobecarefullycontrolledandmonitoredduringtheplasmasprayingprocess.

Finally,thereisaneedtoinvestigatethefeasibilityofusingsustainablematerials,suchasnaturalfibersandbio-basedpolymers,forplasmasprayedcoatings.Thesematerialscanoffersuperiormechanicalandthermalpropertiesandreducedenvironmentalimpactcomparedtotraditionalmaterials.However,theirsuitabilityforplasmasprayingneedstobecarefullyevaluated,andappropriateprocessingtechniquesneedtobedeveloped.

Inconclusion,plasmasprayingtechnologywithNi-Cr-B-Sialloypowderhasshownpromisingpotentialinvariousapplications,buttherearestillsignificantchallengesthatneedtobeovercomeforitspracticalimplementation.Thedevelopmentofadvancedplasmasprayingtechniques,reliabletestingmethods,andefficientpowderproductionmethods,aswellastheinvestigationofsustainablematerials,willcontributetotheadvancementofplasmasprayedcoatingsandbringsignificantbenefitstovariousindustries.Anothercriticalaspectthatrequiresattentionregardingtheplasmasprayingprocessisthecontrolandoptimizationofthecoatingparameters.Theoptimizationofplasmasprayingparameters,suchasplasmagasflowrate,powderfeedrate,andstandoffdistance,cansignificantlyaffectthecoatingpropertiesandperformance.Therefore,itisessentialtodevelopreliableandefficienttechniquesfortheoptimizationoftheseparameterstoensureconsistentcoatingqualityandproperties.

Furthermore,post-processingtechniques,suchasheattreatmentandsurfacefinishing,canplayacrucialroleinenhancingthecoatingperformanceandproperties.Forinstance,heattreatmentcanimprovethecoatingadherence,reducetheresidualstresses,andenhancethemechanicalandcorrosionresistanceproperties.Surfacefinishingtechniquescanalsoimprovethecoating'sfrictionandwearresistanceproperties,aswellasitsaestheticappearance.

Additionally,thedevelopmentofadvancedtestingmethodsisessentialtoevaluatethecoatingqualityandproperties.Traditionalcharacterizationmethods,suchasmicroscopyandXRD,canprovidevaluableinsightsintothecoating'smicrostru