学科分类
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81 个结果
  • 简介:Theeffectofanexternalelectricfieldonthecrystallizationbehaviorofamorphous(Nd0.1Fe0.9)3Balloywasinvestigated.ThecrystallizationproductofNd2Fe23B3phasewasobtainedforthisamorphousalloyannealedat923Kfor300sinthepresenceofanexternalelectricfieldof300kV·m-1(50Hz);whilethecrystallizationproductsareNd1.1Fe4B4,α-Fe,andFe3Bphasesunderthesameannealingconditionexceptforfree-electricfield.Ontheotherhand,thesampleswereannealedat1023K,whichishigherthanthedecompositiontemperatureofmetastableNd2Fe23B3phase,for600s.Inthecaseofthepresenceofanexternalelectricfield,themetastableNd2Fe23B3phase,asamainphase,isstillstayedinthesample.ThisfactsuggeststhattheexternalelectricfieldenhancesthestabilizationofthemetastableNd2Fe23B3phase.Theeffectoftheexternalelectricfieldonthephaseselectionandstabilizationwasexplainedintermsofthespecificconductancedifferencebetweenthecrystallizationproducts.

  • 标签: 电场 稀土元素 磁性材料 相位选择 无组织合金
  • 简介:ThemeasurementsoftemperaturedependenceofthemagneticsusceptibilityofLa1-xSrxCoO3perovskiteoxidesatdifferentSrdoping(0≤x≤0.5)andannealingtemperaturewerepresented.Forthesamplewithx=0.1,ashoulderwasobservedaround150K,andapeakwhichisonefeatureofspinglassappearedaround50Kinthecurveofsusceptibilityversustemperature.Thehigh-temperature(250~420K)susceptibilityfitswellwithCurie-Weisslawforallsamples.WeissconstantandeffectivemagneticmomentweredeterminedandtheirvariationswithSrdopingandoxygenannealingconditionwereobtained.TheWeissconstantincreasesmonotonouslywithSrcontentforx>0.2.Thevaluesofeffectivemomentswereinterpretedwiththespinstateofcobaltions.Studiesonthesusceptibilitiesofthesampleswithx=0.2underdifferentpreparationtemperaturesandannealingtemperaturesshowthattherisingofsinteringtemperatureandannealingtemperaturewillincreasethepara-ferromagnetictransitiontemperature,andreducetheeffectivemomenttonormalvalue.OurresultshowsthatbothCo3+andCo4+ionsshouldbeinISstateafterannealingandtheoxygenannealingcausesthetransitionofCo3+spinstatefromHStoIS.

  • 标签: 磁化系数 退火处理 热处理工艺 稀土
  • 简介:ThemagneticpropertiesandthephasestructureofTb1-xPrxFe1.96(x=0,0.1,...,0.7)werestudied.ItisfoundthatthesaturationmagnetizationoneasyaxisisdecreasedwithincreaseofPrcon-tent,from77.24Am^2·kg^-1forx=0,reducestominimumvalueof11.84Am^2·kg^-1forx=0.5,andreturnesto37.14Am^2·kg^-1forx=0.7.Thenon-cu-bicphasesappearbeyondx=0.2andthematrixchangesfrom1:2phaseforx=0to1:3phaseforx=0.4,atlastto2:17phaseforx=0.7.Thecom-poundsstructurewouldturnmorecomplexasthePrcontentincreases.

  • 标签: 磁性 相结构 磁致伸缩材料 稀土元素 混合物
  • 简介:Duetotheremarkablemagnetoresistance(MR)effectonperovskite-typemanganite,magnetoelectronicsandspintronicshavebecomeattractivesubjectsofexperimentalandtheoreticalinvestigationsfortheapplicationpurpose.(La0.9Nd0.1)2/3Ca1/3Mn1-xFexO3(x=0,x=0.05)werepreparedsuccessfullybysol-gelmethod.Thestructure,magneticproperties,andtransportpropertiesofthecompoundswereinvestigated.Themagnetoresistanceeffectdependsonthecompositionandthetemperature.XRDpatternsshowthatthecompoundisasinglephasepolycrystalwithpseudocubicstructure.Alargenegativeisotropicmagnetoresistanceeffectinthesampleswereobservedatlowtemperatureregion.ThemaximumMRofthesampleswas77%and97%,respectively.Itwasmostlikelyduetothescatteringorthetunnelingtransportofspin-polarizedcarriersinlatticeunderstrongmagneticfield.

  • 标签: SOL-GEL method MAGNETORESISTANCE effect PEROVSKITE pseudocubic
  • 简介:Pr2Fe14B-La2Fe14B系统被衍射(XRD),微分扫描热量测定(DSC)和扫描电子显微镜学(SEM)与精力装备了的X光检查粉末调查散X光检查光谱学(版本)。水晶结构参数被完整侧面的Rietveld精炼决定。结果揭示了那所有合金(Pr1-xLax)2Fe14B使Nd2Fe14有空格组P42/mnm的B类型结构并且形成了连续固体在x=0.0之间的解决方案并且1.0。格子参数一,c,单位房间体积V和c/a比率与La集中线性地增加了。由thermogravimetry分析决定了,居里温度(TC),阶段转变温度和融化的温度(Pr1-xLax)2Fe14B在La内容之上线性地减少了。基于DSC大小和X光检查粉末衍射考试的结果,Pr2Fe14B-La2Fe14B系统被建立。

  • 标签: 水晶结构 格子参数 居里温度 热分析 稀土元素
  • 简介:Magnetizationanddemagnetizationcurvesandhysteresisloopsapplieddifferentmagnetizing.fieldsinsinteredNd-Fe-BandNd-Dy-Fe-Bmagnetsfromthermallydemagnetizedanddcfield-demagnetizedstateswereinvestigatedattemperaturesofupto150℃.Thefirst-quadrantremagnetizationcurvesandthecurvesofcoerciveforces_MH_CversusrernagnetizingfietdsH_mfromdcfield-demagnetizedstateatroomtemperatureshowasteparoundmagnetizingfieldasabsolutevalueofthemaximumintrinsiccoercivity.Thestepsof_MH_C-H_mcurvesshiftedtolowerremagnetizingfieldsandtheshapesofmagnetizationcurveschangedfromsteptypetoprecipitoustypewhentemperaturewentupto100~150℃orafterthespecimenwasthermallydemagnetizedatatemperaturehigherthantheCurietemperature.Thesteepriseofkneecoereivitywithincreasingmagnetizingfieldisbehindthatof_MH_C.NotethatthemagnetichardeninginsinteredNd-Fe-Bmagnetsiscontrolledbypinningofdomainwalls.

  • 标签: MAGNETIZATION COERCIVITY thermally HYSTERESIS ABSOLUTE walls
  • 简介:通过生产过程参数对比,查找宏观原因,并进行解剖,用SEM扫描电镜进行能谱分析,定性分析AAR-B车轮超声检测缺陷的原因,制定改进措施,使产品质量稳定。

  • 标签: AAR-B车轮 缺陷 超声检测 定性分析
  • 简介:InordertoimprovethehydrogenationanddehydrogenationperformancesoftheMg2Ni-typealloys,MgwaspartiallysubstitutedbyLainthealloy,andmeltspinningtechnologywasusedforthepreparationoftheMg20-xLaxNi10(x=0,2,4,6)hydrogenstoragealloys.ThestructuresofthealloyswerestudiedbyX-raydiffraction(XRD),scanningelectronmicroscopy(SEM)andhigh-resolutiontransmissionelectronmicroscopy(HRTEM).Itwasfoundthatnoamorphousphaseformedintheas-spunLa-freealloy,buttheas-spunalloyscontainingLaheldamajoramorphousphase.WhenLacontentx≤2,themajorphaseintheas-castalloyswasMg2Niphase,butwithfurtherincreaseofLacontent,themajorphaseoftheas-castalloyschangedintoLaNi5+LaMg3phase.Thermalstabilityoftheas-spunalloyswasstudiedbydifferentialscanningcalorimetry(DSC),showingthatspinningratewasanegligiblefactoronthecrystallizationtemperatureoftheamorphousphase.Thehydrogenabsorptionanddesorptionkineticsoftheas-castandas-spunalloysweremeasuredusinganautomaticallycontrolledSievertsapparatus,confirmingthatthehydrogenabsorptionanddesorptioncapacitiesandkineticsoftheas-castalloysclearlyincreasedwithrisingLacontent.ForLacontentx=2,theas-spunalloydisplayedoptimalhydrogendesorptionkineticsat200°C.

  • 标签: 熔融纺丝技术 熔融合金 非晶相 放氢 高分辨透射电子显微镜 扫描电子显微镜
  • 简介:结合实例,分析数控车削加工中的基本工艺、机床坐标系和工件坐标系的建立问题;针对FANUC0i系统数控车床的对刀法,阐述了多把刀具的对刀步骤;并对零件进行了手动程序编制.

  • 标签: FANUC0i数控系统 试切法 对刀 手动编程
  • 简介:介绍不锈管坯钢Cr18Ni12Mo2Ti的冶炼和加工工艺并作了分析探讨。检验分析了该钢的化学成份,显微组织和夹杂物等,结果表明,太钢生产的不锈管坯钢Cr18Ni12Mo2Ti完全能够达到技术条件的要求,说明现行的生产工艺是可行的。

  • 标签: 不锈管坯钢 试制 冶炼 加工工艺
  • 简介:为不断开拓镍及镍合金产品市场,扩大高镍产品产量,在1万吨/年镍及镍合金生产线上进行了软磁合金1J50、H79产品的开发。采用真空感应熔炼-锻造-热轧-冷轧工艺得到软磁合金带材与棒材样品,产品化学成份、磁性能和精度达到了国家标准与用户要求。

  • 标签: 软磁合金 产品 开发
  • 简介:Microporoustitaniumdioxidefilmswerepreparedbythesol-gelmethodsonglasssubstrates,usingtetrabutyltitanateassourcematerial.Inordertoabsorbthevisiblelightandincreasethephotocatalyticactivities,differentconcentrationsofneodymiumions(Nd/Timolarratiowas0.5%,0.7%,0.9%,and1.1%respectively)wereaddedintothesol.X-raydiffraction(XRD),X-rayphotoelectronspectros-copy(XPS),andatomforcemicroscopy(AFM)wereappliedtocharacterizethemodifiedfilms.Akindoftypicaltextileindustrypollutant(RhodamineB)wasusedtoevaluatethephotocatalyticactivitiesofthefilmsundervisiblelight.TheresultsshowedthattheactivitiesofthefilmswereimprovedbydopingNdionsintothesol.

  • 标签: TITANIUM dioxide VISIBLE light DOPING ion
  • 简介:Theaimofthisresearchistopulseco-depositnano-CeO2particlesintoNi-W-Balloycoatingsinordertoimprovethesurfaceproperties.Theinfluenceofpulsefrequencyanddutycircleondepositionrate,microhardnessandmicrostructures,andtheinfluenceofheattreatmenttemperatureonphasestructures,microhardnessandabrasivityofNi-W-B-CeO2compositecoatingswereinvestigated.Theresultsindicatedthatthepulseco-depositionofnickel,tungsten,boronandnano-CeO2particlefromthebathwhichnano-CeO2particlewassuspendedbyhighspeedmechanicalstirringledtotheNi-W-B-CeO2compositecoatings,possessingbettermicrohardnessandabrasionresistancewhenheat-treatedat400℃for1h.Themicrohardnessas-depositedwith636Hzandthedepositionratewith0.0281mm·h-1wasthehighestatpulsefrequencywith1000Hzandpulsedutycirclewith10%.Microstructuresanalysisdisplaysthatdecreasingpulsedutycycleleadstorefinementingrainstructuresandtheimprovementofmicrostructures.X-raydiffractionshowsthatthecompositecoatingas-depositedwasmainlyintheamorphousstateandpartiallycrystallized,butwhenheattreatedat400℃,thecrystallizationtrendwasstrengthenedfurther.

  • 标签: pulse ELECTRODEPOSITION composite coatings deposition rate
  • 简介:对10B21冷镦钢盘条出现的冷镦开裂现象,用光学显微镜、扫描电镜、直读光谱仪对缺陷部位进行了显微组织、化学成分等分析。结果表明,冷镦开裂是由钢坯裂纹缺陷所导致,且通过Ti元素的加入,杜绝了钢坯裂纹的产生。

  • 标签: 10B21 冷镦钢 盘条 开裂
  • 简介:InordertoimproveandstabilizethemagneticpropertiesofnanocompositeNd2Fe14B/α-Femagneticalloysbyacompositionaladjustment,smallamountofDyand/orCowasaddedtoNd9Fe84B7alloys.DTAanalysisontheamorphousofthealloystookplaceasthesoftmagneticphaseswerecrystallized,andthenthehardmagneticNd2Fe14Bwasprecipitatedfromthem.Whileα-Feandametastable1:7(TbCu7-type)phasewereformedsimultaneouslyinDyandCo-freealloys,theywerecrystallizedseparatelyatdifferenttemperaturesafterDyorCowasadded.ThisphaseseparationoccurredmoreclearlyintheDy-treatedalloysandtheothersoftmagneticphaseFe3BwasalsostabilizedbyDyand/orCo.The1:7phasethatwasstabilizedbyDyand/orCowasnoteliminatedat700℃,decreasingmagneticpropertiesofthealloys.Itwaseventuallydisappearedabove725℃,butFe3Bwasnoteliminatedevenat750℃whenDywasaddedmorethan0.5at%orCowasaddedmorethan2.0at%.AmountofNd2Fe14BinthealloystendedtoincreaseasDyadditionincreased,whereasCoadditiondidnotleadtoanyappreciablechangeintheratioofα-FeandNd2Fe14B.Moreover,DyadditionapparentlyincreasedcoercivityofanalloywhileCoadditionhadabeneficialeffectonremanence.ThegrainsintheDytreatedalloyswereusuallyfinerthanthoseintheCo-treatedalloys.Thegrainsizeofbothα-FeandNd2Fe14Binthealloysexhibitingmr≥0.72wasintherangeof20~40nmorevenlarger50nm,whichislargerthanthetheoreticaloptimumsize(~10nm).TypicalmagneticpropertiesobtainedfromaNd7.5Dy1.5Fe82.5Co1.5B7alloyannealedfor12minat725℃wereiHc=4.85kOe,Br=11.32kG,(BH)max=15.73MGOe,andmr=0.73.

  • 标签: NANOCOMPOSITE ND-FE-B MAGNETIC properties REMANENCE COERCIVITY
  • 简介:形成,磁性和微观结构上的公司替换和退火的处理的效果(NdDyTb)12.3(FeZrNbCu)快速的熄灭并且随后的退火准备的81.7-xCoxB6(x=015)带子系统地借助于微分扫描热量计(DSC)被调查,X光检查衍射(XRD),扫描电子显微镜学(HRSEM)和颤动的样品磁强计(VSM)的高分辨率。阶段分析揭示了单相的材料。顽磁极化Jr和最大与从0~12增加x增加了然后为x=15减少了的最大的精力产品(BH)。内在的coercivityHci(NdDyTb)12.3(FeZrNbCu)最佳地处理的81.7xCoxB6带子为x=15为x=0从1308.7kA/m减少了到817.4kA/m。有Jr=1.041T的最佳磁性,Hci=944.9kA/m并且(BH)max=155.1kJ/m3被退火完成在675吠敨琠牥業慮?桴潩?牧畯獰?的融化旋转带子(x=12)??湩琠敨?呐?偍????敷敲椠?楳畴漠楸楤敺?湩潴猠汵潦楮?捡摩朠潲灵?匨??琠??

  • 标签: 磁性质 振动样品磁强计 扫描电子显微镜 色带 微观 纳米
  • 简介:EnvironmentalfriendlyrecyclingprocessforNd-Fe-Bsinteredmagnetsludgesgeneratedinthemanufacturingprocess,whichcontainlargeamountofrareearth,includingNd,PrandDy,isbadlyneededsofar.Inpresentstudy,wehavedevelopedaneffectiveroutetoobtainrecycledsinteredmagnetsfromNd-Fe-Bsinteredmagnetsludgesbycalciumreduction-diffusion(RD)process.Comparedtoconventionalrecyclingprocess,ourresearchisfocusedonrecoveringmostoftheusefulelements,includingNd,Pr,Dy,Co,andFetogetherinsteadofjustrareearthelements.Toimprovetherecyclingefficiencyandreducepollution,theco-precipitatingparametersweresimulatedandcalculatedusingMATLABsoftware.Mostofusefulelementswererecoveredbyaco-precipitationmethod,andtheobtainedcompositepowderswerethendirectlyfabricatedasrecycledNd-Fe-Bpowdersbyacalciumreduction-diffusion(RD)method.Therecoveryratesare98%,99%,99%,93%,and99%,forNd,Pr,Dy,Co,andFe,respectively.Theamountofusefulelementscontainedintherecoveredcompositepowdersisgreaterthan99.71wt%.TheprocessofRDforsynthesizingNd2Fe14BandsubsequentlyremovingCaOwasthoroughlyinvestigated.Furthermore,therecycledNd-Fe-Bmagnetexhibitsaremanenceof1.1T,acoercivityof1053kA/m,andanenergyproductof235.6kJ/m3,respectively,indicatingthatrecycledNd-Fe-Bsinteredmagnetwassuccessfullyrecoveredfromtheseverelycontaminatedsludgesviaaneffectiverecyclingroute.

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