各向同性磁体

PresslessprocessforisotropicmagnetsanditsapplicationManlongXia27November2015DTUEnergy’sannualPhDsymposiumDTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”Outline•Introduction–Theapplicationofmagnet–ThePress-lessProcess(PLP)•Experimentalwork–ThePresslessandcompactmagnetsfromstripcastmaterial•DiscussionaboutPLPmethodusingforrecyclingmagnets•ConclusionDTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”Criticalelementsforcleanenergytechnology-U.S.strategyU.S.DepartmentOfEnergy,CriticalMaterialsStrategy,December2011DTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”AlternativesuppliesofREtoDanishindustryRFeBmagnetsApplicationsRmetalRareearthoxidesMineralRockRFeBPowderToyotaPriusMotor1kgPM/carDirectdrivewindturbineSWT-3.0-1012tonsPM/3MWturbineWaste!Recycling?DTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”R2Fe14BmagneticalloyNedkoDrebovetal,Abinitioscreeningmethodologyappliedtothesearchfornewpermanentmagneticmaterials.NewJournalofPhysics15(2013)125023N48McommercialmagnetDTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”VacuumschmelzePatent:EP0680054B2(2004)T1:Nd2Fe14BT2:Nd1+€Fe4B4Sagawaet.al.,“Nd–Fe–BPermanentMagnetMaterials,”Jpn.J.Appl.Phys.,vol.26,pp.785-800,1987.P.Bøjsøe,PhDthesis1990.PhasediagramDTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”PressLessmethodSagawa(2012)Patent:EP2472535A1(2012)JetMillGraphitemouldCompactingAlignmentmagnetHeatingcoils(250oC)VacuumfurnaceMouldstackingM.Sagawaprepared0.3µmpowderbyHDDR+HD+HejetmillDTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”TheprincipleforPresslessprocesscompactPLPPLPprocesscanproducelowoxygencontentofsamplebyenclosethewholesysteminargon.K.HonoandH.Sepehri-Amin.ScriptaMaterialia67(2012)530–535DTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”MethodsAdvantageDisadvantageCompactmethod•Easytogetdenseandahighermagneticproperties.•Successfulintheindustrialproduction.•Bigpressmachineisneeded.•Theoxygencontentcan’tgodownanymore.Presslessmethod•Savethepressmachineandrelatedcosts.•Canintegratethewholesystemtogetloweroxygencontent.•CanacquirehighcoercivityNdFeBmagnetswithoutDy.•Porosity:hardtogetdense•Remanenceand(BH)max:NoreportaboutusingPLPmethodtoprepareN52magnets.DTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”Presslessprocessandtraditionalcompactmethodinexperiment•Twokindsofstrip-castNdFeBalloyswereusedinourexperiment:–Dy=0wt%(BL8214)–Dy=4wt%(48508)•Thestripcastalloysweresubjectedtohydrogenin2hoursforroughgrinding.•DryhighenergyballmillinginDTUandjetmillinginTallinnTechnologyUniversitywereusedtoproducefinepowder.•ForPresslessmethod,tapthefinepowderintographitecruciblestoadensityof3g/cm3.TomakeacomparisonwithsamplespreparedbyPresslessmethod,wealsocompactthesamplewithaxialpress(445MPapressure).•Thesamplesweretransportintofurnacetubetodopumpandprepareforsintering.Thesinteringprogramisshownbelow.Thesinteringtimewillbe2handwesinteredsamplesat1090,1110and1130℃,andthencooldown.DTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”Sinteringprofile25/4-2012timeTemp[oC]2oC/min250oC*1h2oC/minTsinter*2h5oC/min570oC*1hcoolingDTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”Successfulmagnet’smicrostructure:thingrainboundaryThemicrostructureof48508(4wt%Dy)1130℃PLPsample.Backscatteredelectrons(BSE)Secondaryelectrons(SE)2µm2µmGrainboundaryGrainboundaryDTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”0wt%Dy(BL8214)PLPsamples1090℃*2h1110℃*2h1130℃*2hDTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”4wt%Dy(48508)PLPsamples1110℃*2h1090℃*2h1130℃*2hDTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”PLPvscompactmagnets25/4-2012DTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”TheinterestingfactaboutPresslessProcessOxygencontent4wt%DyPLPsamplewassinteredat1110℃for2h,thesample’soxygencontentis6101ppm,however,thecoercivityofthesampleisstill368kA/m.InitialpowdersizeUsinghighenergyballmillingtodrymill4wt%Dysample,wegotpowderwhosemeansizeis46.18µm(laser).Usingthesetodopresslessprocessandsinteredat1110℃for2h,wegotsinteredsampleswhosemagneticpropertiesare:Hci=1022kA/m,Br=0.69T.DTUEnergy,TechnicalUniversityofDenmarkAddPresentationTitleinFootervia”Insert”;”Header&Footer”Conclusion•WesuccessfullypreparedhighdensitysamplesbyPress-Lessprocessbyjetmillingpowderandhighenergydryballmillingpowder.Thekeyissueforthisprocessareacquired.•WefoundthePresslessprocesscanacquiresimilarpropertiesastraditionalcompactionmethod,whichespeciallycanapplytorecyclemagnets,withacheaperpri