外文翻译--半连不锈钢AISI 304的等离子膏剂渗硼处理.doc -- 5 元

PlasmapasteboronidingtreatmentofthestainlesssteelAISI3041.IntroductionAA3003alloysinrecentyears,thedevelopmentofsurfacetreatmentprocesshasbeenextensiveresearchtoimprovetheapplicationofstainlesssteelunderhightemperatureandpressurewearandoxidationresistance.Stainlesssteelsurfacetreatmentmethodsavailable,includingnitrogen2,carburizing,plasmacoating,boronpenetrationInparticular,theborideisboronpenetrationanddiffusionintothesurfaceoftheboridelayerhardnessHVbetweenin13002100ofthesurfacetreatment.Boridelayerhasexcellentheatresistanceandcorrosionresistance,andboridehavebeenappliedtoimprovethevalve,burners,nozzlesandothersurfaceproperties,whentheyareexposedtohightemperatureandpressurewheninthewaterandoil.Recently,however,improvedtechnologysuchasplasmaBoronizinginfiltrationprocesshasbeenextensivelystudied,becausethetraditionalboronizingprocess,suchastheofficialsaltbathandgasnitridingboronboronwillappear,suchasenvironmentalpollution,toxic,explosivenatureoftheproblem.Plasmaboronizinghasmanyadvantagesovertraditionalboronizingprocess.Forexample,expectahighenergyefficiencyasasourceofhighenergyplasmatobeusedinplasmaboronizingprocess,anddistortioncanbeminimized,becausetheprocessingtemperatureisrelativelylowerthanthetraditionalprocess.However,plasmaboronizingprocessalsohasitsownlimitations.BZH6andBC13gaswasusedasaboronsourcegas,butgasisrelativelyexpensiveandtoxic,explosive.Inavacuumchamberbyboronchloridecorrosionisanotherseriousproblemfortheplasmaboronizing.Inthisstudy,asthedevelopmentofasolutiontotheproblemmentionedaboveandmoreintheprocessofboronpenetrationinoneattempt,involvingtheuseofamorphousboronandboraxNa2B4O7creamisasimpleprocessofplasmaPastyboronizingmethodshavebeendesigned,thebestplasmaboronizingpastehasconductedasurveyofprocessconditions,thustheformationofboridelayermethodhascertaincharacteristics2.ExperimentalTherealAISI304stainlesssteelspecimensdiameter15mm,thickness2.5mmwasusedforthistest.Sandpaper1200,afterpolishingthesurfaceofthesamplespecimen,cleanoffthedirtafterthesamplesarebroughtintothelaboratory,intheH2atmosphereforsputtercleaningofthespecimenisthefirsttobecarriedout.InArH221gasenvironment,withdifferentproportionsofboronandboraxmixtureofboronpenetrationagentsdoboronizingplasmatreatmentbegan,in1023,1073,1123,1173and1223Kseveralheatedatdifferenttemperaturesforupto7hours.UsingmicroscanningelectronmicroscopeHitachi52400tostudyitsmicroscopicstructure,acceleratingvoltageof20kVelectronmicroprobeanalysisdone.Vickershardnesswasmeasuredusinga0.1kgforceload,usingtheaverageofsevenreadings.CuKraydiffractionXraydiffractionanalysiswasused.PlasmaPastyborideofapparatusanddetailsofothertrialsinreference6usingdescription.3.Resultsanddiscussion3.1CreammixtureratioofboridelayerformationFig1Theeffectofvariousratiosofamorphousboronandboraxmixturethicknessoftheboridelayer.Fig.1showstheproportionofpastewithdifferentborideinthe1123Ktemperatureinsulation1.5hoursaftertheboridelayerthickness.Observedwiththemassfractionof20and70ofboraxtoformathickboridelayer.Andwiththemassfractionof100ofamorphousborontoformanymeasurablethicknessofboridelayerisnotobserved,whichmaybeattributedtothepenetrationofboroninplasmaduringtheamorphousboronasthemeltingpointduetosurfacediffusionofthelackofactivityofboron.Whenthemassfractionofboraxto20,theactiveformoftheboridelayerwasobserved.Duringtheinfiltrationofboron,boronatoms,B0,iscreamoftheboronhydrideBnHmofdecomposition,andtheboronatomsintothemoltenboraxorB0glowdischargeintheactiveboronatomsB1.Finally,theboronatoms,B1,proliferation,andironreaction,andthentheformationofboridelayer.Withthemassfractionof30and70oftheboronpasteofboraxboridelayerformationwasalsoobserved,whichmaybeattributedtotheeffectivemechanismofliquidelectrolyte,whentheboraxwiththecreamintheincreaseinthenumber,themobilityofmoltenboraxincreasethetime.Moreover,themassfractionof40and55ofthepaste,whentheslowrateofboridewasobserved,asshowninFigure1.Presumably,forincludinggas,electrolysis,electrolysis,etc.,avarietyofnonliquidboronizingmechanism,theactiveingredientinthisrangewillbedifficultforsomereason,theneedforfurtherinvestigation.Figure1stainlesssteelboridelayerthicknesslessthanmildcarbonsteel,whichconfirmspreviouslyreportedresults7,8.Notonlybecauseofthestainlesssteelsurfacehasaprotectivelayer,butalsoinchrome,nickelborideonthesurfacebutalsotheprotectivelayer,theyformwiththegrainboundary,therebypreventingthediffusionofboron7,8.Itwasalsopointedoutthat,duetotheincreaseinthenumberofboron,pastebecomesexcessive,adhesiveonthesurfacewhentheplasmasamplesPastyboronizingbegan,leadingtotherecoveryofthiscreamisverylow.Consideringthehighcostofboron,thereforeinferplasmaPastyPastyboridecomponentswiththebestmassfractionof30amorphousboronand70ofborax.3.2EffectoftemperatureandtimeontherateofformationoftheboridelayerFig.2.RelationbetweentheboronidingtemperatureandtimesontheFigure2showsthetemperatureandtimeontheborideboridelayerdepth.Accordingtotheparabolictheory,withtheinfiltrationtimeandtemperatureincreasedboron,boridelayerdepthwillalsoincrease.Thisshowsthattheboridelayerformationratebecomesslowastimeincreasesboronpenetration.ThiscanbeexplainedbythefactthattheformationofboridelayeronthesurfaceoftheNirichlayerbelowandchromiumrichlayerplaystheroleofdiffusionbarrier,inhibittheactivityofborondiffusion.Furtherexplanationwillbegivenlaterinthearticle.3.3ChangesincrosssectionhardnessdistributionFig.3.HardnesscurvesofAISI304boronizedforvarioustimesat1173K.Plasmaboridespecimensin1023,1073,1123K,holdingsevenhourstogettheboridelayerthicknesscannotbemeasured,andtheirhardnessmeasurementisimpossible.In1173and1223Ktemperatureplasmaboronizing,inanycase,theformationof30to40micronsthickboridelayerboridesamplesofplasmafor7hoursat1223KcrosssectionhardnessmeasurementresultsaresummarizedinFigure3on.Borideinplasma7hoursafterthespecimensfoundonthemaximumdepthofthenitridedlayerof45microns,andthemaximumhardnessof1800to2000ofthenitridedlayer.