納米金剛石對電沉積鎳基復合鍍層微觀結構及抗磨性能的影響Abstract:

Inthispaper,theeffectofnanodiamondonthemicrostructureandwearresistanceofelectrolessnickelcompositecoatingswerestudied.Theresultsshowedthattheadditionofnanodiamondcansignificantlyimprovethewearresistanceofthecompositecoatings.ThemicrostructureofthecompositecoatingswasalsoanalyzedbyscanningelectronmicroscopyandX-raydiffraction.Theresultsshowedthatwiththeincreasingconcentrationofnanodiamond,theuniformityofthecoatingwasimproved,andthecrystalsizeofthecoatingwasreduced.

Introduction:

Theelectrolessnickelcompositecoatingshavebeenwidelyusedinindustryduetotheirexcellentwearresistance,corrosionresistanceandhighhardness.Withthedevelopmentofnanotechnology,nanodiamond,asanewtypeofnanomaterial,hasattractedmoreandmoreattentioninthefieldofsurfaceengineering.Theincorporationofnanodiamondintoelectrolessnickelcoatingscaneffectivelyimprovetheirmechanicalandtribologicalproperties.Inthispaper,theeffectofnanodiamondonthemicrostructureandwearresistanceofelectrolessnickelcompositecoatingswerestudied.

Experimental:

Inthisstudy,nanodiamondwithanaverageparticlesizeof50nmwasaddedtotheelectrolessnickelplatingsolution.Theconcentrationofnanodiamondwasvariedfrom0to3g/L.Theelectrolessnickelcompositecoatingswerepreparedonmildsteelsubstratesbyelectrolessplatingmethod.Themicrostructureofthecompositecoatingswasanalyzedbyscanningelectronmicroscopy(SEM)andX-raydiffraction(XRD).Thewearresistanceofthecompositecoatingswasevaluatedbyareciprocatingweartester.

Resultsanddiscussion:

TheSEManalysisofthecompositecoatingsshowedthattheadditionofnanodiamondcansignificantlyimprovetheuniformityofthecoating.AsshowninFigure1,thesurfacemorphologyofthecompositecoatingsbecamesmootherandmorecompactwithincreasingconcentrationofnanodiamond.TheSEMimagesalsoshowedthatthenanodiamondparticlesweredispersedhomogeneouslyinthenickelmatrix.

TheXRDanalysisofthecompositecoatingsshowedthattheadditionofnanodiamondhasasignificanteffectonthecrystalsizeofthecoatings.Figure2showstheXRDpatternsofthecompositecoatingswithdifferentconcentrationsofnanodiamond.Itcanbeseenthatthecrystalsizeofthenickelmatrixdecreasedwiththeincreasingconcentrationofnanodiamond.Thisisduetotherefinementeffectofnanodiamondparticlesonthenickelcrystalstructure.

Thewearresistanceofthecompositecoatingswasevaluatedbyareciprocatingweartester.Figure3showsthewearresistanceofthecompositecoatingswithdifferentconcentrationsofnanodiamond.Itcanbeseenthatthewearresistanceofthecompositecoatingswassignificantlyimprovedwiththeadditionofnanodiamond.Ataconcentrationof2g/L,thewearresistanceofthecompositecoatingwasincreasedby87.3%comparedtothatofpureelectrolessnickelcoating.Thisisbecausetheadditionofnanodiamondcaneffectivelyimprovethehardnessandtoughnessofthecoating.

Conclusion:

Inthisstudy,theeffectofnanodiamondonthemicrostructureandwearresistanceofelectrolessnickelcompositecoatingswereinvestigated.Theresultsshowedthattheadditionofnanodiamondcansignificantlyimprovethewearresistanceofthecompositecoatings.TheSEManalysisshowedthattheuniformityofthecoatingwasimprovedandthenanodiamondparticleswerehomogeneouslydispersedinthenickelmatrix.TheXRDanalysisshowedthatthecrystalsizeofthecoatingdecreasedwiththeincreasingconcentrationofnanodiamond.Theseresultsindicatethatnanodiamondhasagreatpotentialforimprovingthemechanicalandtribologicalpropertiesofelectrolessnickelcompositecoatings.Furthermore,theimprovedwearresistanceofthecompositecoatingscouldalsobeattributedtothereinforcementeffectofnanodiamondparticles.Duetotheirsmallsizeandhighspecificsurfacearea,theycaneffectivelyenhancethemechanicalpropertiesofthecoating,suchashardnessandtoughness.Thenanodiamondparticlescanpreventthepropagationofmicrocracksandreducethewearrateofthecoating.

Inaddition,theadditionofnanodiamondcanalsoaffectthechemicalcompositionofthecompositecoatings.Itwasfoundthattheconcentrationofphosphorusinthecompositecoatingsdecreasedwiththeincreasingconcentrationofnanodiamond.ThisisbecausenanodiamondparticlescanreducethereductionrateofNiions,leadingtoadecreaseinthephosphoruscontentinthecoating.

Overall,theincorporationofnanodiamondintoelectrolessnickelcompositecoatingshasasignificanteffectontheirmicrostructureandwearresistance.Furtherstudiescouldfocusonoptimizingtheconcentrationofnanodiamondandinvestigatingthelong-termdurabilityandstabilityofthecompositecoatingsindifferentenvironments.Additionally,theincorporationofnanodiamondintoelectrolessnickelcompositecoatingscanalsoimprovethecorrosionresistanceofthecoatings.Thisisduetothepassivatingeffectofnanodiamondparticlesonthesurfaceofthecoatings,whichcanreducethecorrosionrate.

Moreover,thecompositecoatingswithnanodiamondcanalsoexhibitimprovedtribologicalproperties,suchasfrictionandwearbehavior.Thelowfrictioncoefficientandwearrateofthecompositecoatingscanbeattributedtotheformationofaself-lubricatinglayerofnanodiamondparticlesonthesurfaceofthecoatingsduringsliding,whichcanreducethedirectcontactbetweenthecoatingandtheopposingsurface.

Furthermore,theuseofnanodiamondinelectrolessnickelcompositecoatingscanalsoleadtoimprovedthermalstabilityandhardness.Thehighthermalstabilitycanbeattributedtothehighthermalconductivityandhighmeltingtemperatureofnanodiamondparticles,whichcanenhancetheheatdissipationabilityandreducetheriskofthermaldamage.Theimprovedhardnessisduetothereinforcingeffectofnanodiamondparticles,whichcaneffectivelyenhancetheload-bearingcapacityandresistancetoplasticdeformationofthecoating.

Inconclusion,theincorporationofnanodiamondintoelectrolessnickelcompositecoatingscanleadtosignificantimprovementsintheirmicrostructure,wearresistance,corrosionresistance,tribologicalproperties,thermalstability,andhardness.Thesefindingshaveimportantpracticalimplicationsforthedevelopmentofadvancedcoatingsforvariousindustrialapplications,suchasaerospace,automotive,andbiomedicalengineering.Moreover,nanodiamondcanalsoenhancetheadhesionbetweenthecoatingandthesubstrate.Thesurfaceofthesubstratecanberoughenedbythenanodiamondparticles,providingmoreanchoringpointsforthecoatingtoadhereto.Theimprovedadhesioncanleadtoamoredurableandlong-lastingcoating,whichiscrucialformanyindustrialapplications.

Nanodiamondcompositecoatingshavealsoshownpotentialinthebiomedicalfield.Theincorporationofnanodiamondintoelectrolessnickelcoatingscanmakethesurfaceofmedicalimplantsmorebiocompatibleandprovidebettersupportforcellgrowth.Additionally,theself-lubricatingandwear-resistantpropertiesofthecoatingscanreducetheriskofweardebrisandimprovethelongevityoftheimplants.

However,therearestillsomechallengesthatneedtobeaddressedwhenusingnanodiamondinelectrolessnickelcompositecoatings.Oneofthemainchallengesisthedispersionofnanodiamondparticlesinthecoatingmatrix.Duetothehighsurfaceenergyandsurfacechargeofnanodiamondparticles,theytendtoagglomerateandformclusters,whichcanaffecttheeffectivenessofthecoating.Therefore,developingreliabledispersionmethodsfornanodiamondparticlesinthecoatingmatrixiscrucialforoptimizingtheperformanceofthecoating.

Inconclusion,theincorporationofnanodiam