化学镀镍磷合金英文文献

化学镀镍磷合金的英文文献

MaterialsandDesign31(2010)

3174–3179

ContentslistsavailableatScienceDirect

MaterialsandDesign

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AninvestigationoneffectsofheattreatmentoncorrosionpropertiesofNi–Pelectrolessnano-coatings

TaherRabizadeh,SaeedRezaAllahkaram*,ArmanZarebidaki

SchoolofMetallurgyandMaterialsEngineering,UniversityCollegeofEngineering,UniversityofTehran,P.O.Box11155-4563,Tehran,Iran

articleinfoabstract

ElectrolessNi–Pcoatingsarerecognizedfortheirexcellentproperties.Inthepresentinvestigationelec-trolessNi–Pnano-crystallinecoatingswereprepared.X-raydiffractiontechnique(XRD),scanningelec-tronmicroscopy(SEM),potentiodynamicpolarizationandelectrochemicalimpedancespectroscopy(EIS)wereutilizedtostudypriorandpost-depositionvacuumheattreatmenteffectsoncorrosionresis-tancetogetherwiththephysicalpropertiesoftheappliedcoatings.

X-raydiffraction(XRD)resultsindicatedthattheAs-platedhadnano-crystallinestructure.Heattreat-mentofthecoatingsproducedamixtureofpolycrystallinephases.Thehighestmicro-hardnesswasachievedforthesamplesannealedat600°Cfor15minduetotheformationofaninter-diffusionallayeratthesubstrate/coatinginterface.

Lowercorrosioncurrentdensityvalueswereobtainedforthecoatingsheattreatedat400°Cfor1h.EISresultsshowedthatproperheattreatmentsalsoenhancedthecorrosionresistance,whichwasattributedtothecoatings’structureimprovement.

Ó2010ElsevierLtd.Allrightsreserved.

Articlehistory:

Received19January2010Accepted15February2010

Availableonline17February2010Keywords:C.Coating

C.HeattreatmentE.Corrosion

1.Introduction

Sincetheinventionofelectrolessplatingtechnologyin1946byA.BrennerandG.Riddell,electrolessnickel(EN)coatingshavebeenactivelyandwidelystudied[1,2].

Nano-crystallineNi–Palloysshowahighdegreeofhardness,wearresistance,lowfrictioncoef cient,non-magneticbehaviorandhighelectro-catalyticactivity.TodaysuchNi–Palloysarewidelyusedintheelectronicindustryasunder-layerinthin lmmemorydisksandinabroadrangeofotherevolvingtechnologicalapplications.Itisgenerallyacceptedthatonlynano-crystallineal-loys–irrespectiveofthewayofproduction–showhighcorrosionresistance.Indeed,electrodepositedNi–Palloyswithcrystallinestructure(6–11at.%P)showedanodicdissolutionin0.1MNaCl.Onnano-crystallinesamples(17–28at.%P)acurrentarrestwasfoundinstead[3–5].

ToexplainhighcorrosionresistanceofNi–Pelectrolesscoatingsdifferentmodelshavebeenproposed,buttheissueisstillunderdiscussion:aprotectivenickelphosphate lm,thebarrieractionofhypophosphites(called‘‘chemicalpassivity”),thepresenceofphosphides,astableP-richamorphousphaseorthephosphorusenrichmentoftheinterfacealloy-solutionwereproposed.Notethatsuchphosphorusenrichmentattheinterfacewasreported

*Correspondingauthor.Tel./fax:+982161114108.E-mailaddress:akaram@ut.ac.ir(S.R.Allahkaram).

0261-3069/$-seefrontmatterÓ2010ElsevierLtd.Allrightsreserved.bysomeoftheauthorstoexplaintheoutstandingcorrosionresis-tanceofFe70Cr10P13C7amorphousalloys[5].

ElectrolessNi–Palloysarethermodynamicallyunstableandeventuallyformstablestructuresofface-centeredcubic(fcc)Nicrystalandbody-centeredtetragonal(bct)nickelphosphide(Ni3P)compounds.DifferentresultshavebeenreportedregardingthemicrostructuresintheAs-depositedconditionandthestablephasesafterheattreatments.ForlowPandmediumPalloys,nickelcrystalprecipitated rstlyandNi3Pfollowed;however,Ni3Pand(or)NixPycompoundssuchasNi2P,Ni5P2,Ni12P5,andNi7P3occur rstlyinhighPalloys[6–8].

Ingeneral,thehardnessoftheelectrolessNi–Pcoatingscanbeimprovedbyappropriateheattreatment,whichcanbeattributedto neNicrystallitesandhardinter-metallicNi3Pparticlesprecip-itatedduringcrystallizationoftheamorphousphase[8–10].

Themainreasonsforheattreatmentare:(1)toeliminateanyhydrogenembrittlementinthebasicmetal,(2)toincreasedeposithardnessorabrasionresistance,(3)toincreasedepositadhesioninthecaseofcertainsubstrateand(4)toincreasetemporarycorro-sionresistanceortarnishresistance[11].

Thecrystallizationandphasetransformationbehaviorofelec-troless-platedNi–Pdepositsduringthermalprocessinghasalsobeenthesubjectofvariousinvestigations;ithasbeenshownthatdifferentalloycompositionsandheattreatmentconditionscouldaffectboththecorrosionresistanceandcrystallizationbehaviorofthedeposit[8].

化学镀镍磷合金的英文文献

T.Rabizadehetal./MaterialsandDesign31(2010)3174–31793175

Theaimofthisworkistostudythepost-depositionheattreat-menteffectsandcorrosionbehaviorofelectrolessdepositednano-crystallineNi–Palloys.Thetemperaturedependenceofthecoatingstructuresandcompositionswerealsoevaluatedanddiscussed.2.Experimentalprocedures

2.1.DepositionofelectrolessNi–Pcoating

ThedepositionwasperformedonAPI-5LX65steelsubstrates(30Â25Â15mm)withacompositionof(Fe:base,Mn:1.42,Si:0.199,Cu:0.144,Mo:0.132,C:0.061,Nb:0.0538,Al:0.0417,Sn:0.0167,Ti:0.0142,Cr:0.0126,P:0.01).ThesubstratesurfacewascarefullypolishedwithSiCemerypapers(fromgrades#100to#400).Allthespecimensweresubjectedtothefollowingpre-treat-mentandplatingprocedure:

1.Ultrasoniccleaninginacetone.

2.Rinsingbyimmersionindistilledwateratroomtempera-ture(RT)for2min.

3.Cleaningin20vol.%H2SO4atRTfor30s.

4.RinsingbyimmersionindistilledwateratRTfor2min.5.Cleaningin5vol.%H2SO4atRTfor30s.

6.RinsingbyimmersionindistilledwateratRTfor2min.7.Electrocleaninginsolutioncontaining75g/lsodium

hydroxide(NaOH),25g/lsodiumsulfate(Na2SO4),75g/lsodiumcarbonate(Na2CO3),atroomtemperaturefor20min.Thecurrentdensityappliedwas10mA/cm2inaccordancetoASTMG1.

8.RinsingbyimmersionindistilledwateratRTfor30s.Fordeposition,thesubstratesweredippedintocommercialelectrolessnickelbath(SLOTONIP70AfromSchlotter)withsodiumhypophosphiteasreducingagentfor2h.ThisbathprovidedNi–Pdepositswithamediumphosphorouscontent,9–10%P.Tempera-turechangedwithin …… 此处隐藏：19762字，全部文档内容请下载后查看。喜欢就下载吧 ……