简介:Puretungsten(PW)andW-1wt%La2O3(WL10)werepreparedbypowdermetallurgicalroutefollowedbytheswaging+rollingprocess.Thelogarithmicstrainsare0,0.37,0.58,and0.98forWL10and0,0.58forPW.Heattreatmentswereperformedattemperaturesvariedfrom1,573to2,173Ktodeterminetherecrystallizationtemperature.Recrystallizationtemperaturesare1,973and2,173KforWL1(logarithmicstrainof0.37)andWL3(logarithmicstrainof0.98),respectively.ButinthecaseofWL2(logarithmicstrainof0.58),fullrecrystallizationisnotachievedattemperatureofabove2,173K.Furthermore,therecrystallizationtemperatureofPWwithlogarithmicstrainof0.58isatleast300KlowerthanthatoftheequivalentWL10sample.Moreover,theincreaseofrecrystallizationtemperatureinhibitsthestrengthdegradationofWL2:sampleslose4%and22%strengthwhenannealedat1,573and1,973Kcomparedwithroomtemperature(RT)sample.Finally,thetextureevolutionfortheswaged+rolledWL10issignificantlyrelatedtothedeformationdegree:thedominatedorientationis<001>forWL2while<110>forWL3.
简介:Theaxialandradialconvectiveflow,temperaturefluctuationanddistributionintheHMCZsiliconmeltarestudiedtentatively.Theexperimentalresultsshowthattheaxialandradialconvectivespeeds,thetempera-turevariationandtheradialtemperaturegradient,paralleltomagneticfieldandnearmeltsurface,alldecrease,buttheaxisymmetryoftemperaturedistributionnolongerexistswhenthemagneticfieldisapplied.
简介:Permanentmagneticmaterialscapableofoperatingathightemperatureupto500°Chavewidepotentialapplicationsinfieldssuchasaeronautics,space,andelectroniccars.SmCoalloysarecandidatesforhightemperatureapplications,sincetheyhavelargemagnetocrystallineanisotropyfield(6–30T),highCurietemperature(720–920°C),andlargeenergyproduct([200kJám-3)atroomtemperature.However,thehighestservicetemperatureofcommercial2:17typeSmComagnetsisonly300°C,andmanyeffortshavebeendevotedtodevelopnovelhightemperaturepermanentmagnets.ThisreviewfocusesonthedevelopmentofthreekindsofSmCobasedmagnets:2:17typeSmComagnets,nanocrystallineSmComagnets,andnanocompositeSmComagnets.Theoxidationprotection,includingalloyingandsurfacemodification,ofhightemperaturepermanentmagnetsisdiscussedaswell.
简介:Thecombinedquadraticorthogonalregressionmethodofexperimentdesignwasemployedtoexploretheeffectsofprocessparametersofplasmanitridingoftantalumsuchastotalpressure,temperatureandoriginalhydrogenmolarfractiononthehardness,roughnessandstructureofnitridingsurfaces.Theregressionequationsofhardness,roughnessandstructureweregivenaccordingtotheresultsofregressionandstatisticanalysis.Andthediffusionactivationenergyofnitrogenintantalumonplasmanitridingconditionswascalculatedaccordingtotheexperimentaldataofhardnessofplasma-nitridingoftantalumvstimeandtemperature.Thediffusionactivationenergycalculatedbelongsto(155.49+10.51)kJ/mol(783-983K).
简介:IntroductionIMI829titaniumaloyisakindofhightemperaturenearαaloy.Itsservicetemperatureisupto580℃.IthasbeenusedinRB211525E4en...
简介:Ni83Fe17filmswithathicknessofabout100nmweredepositedonthermaloxidizedsiliconsubstratesatambienttemperature,240,350,and410℃byDCmagnetronsputtering.Thedepositionratewasabout0.11nm/s.Theas-depositedfilmswereannealedat450,550,and650℃,respectively,inavacuumlowerthan3x10-3Pafor1h.TheNi83Fe17filmsmainlygrowwithacrystallineorientationof[111]inthedirectionofthefilmgrowth.Withtheannealingtemperatureincreasing,the[111]orientationenhances.Forfilmsdepositedatallfourdifferenttemperatures,thesignificantimprovementonanisotropicmagnetoresistanceoccursattheannealingtemperaturehigherthan550℃.Butforfilmsdepositedatambienttemperaturesand240℃,theanisotropicmagnetoresistancecanonlyrisetoabout1%after650℃annealing.Forfilmsdepositedat350℃and410℃,theanisotropicmagnetoresistancerisestoabout3.8%after650℃annealing.Theatomicforcemicroscopy(AFM)observationshowsasignificantincreaseingrainsizeofthefilmdepositedat350℃atter650℃annealing.Thedecreaseinresistivityandtheincreaseinanisotropicmagnetoresistancearecausedbythedecreaseinpointdefects,theincreaseingrainsize,andtheimprovementinlatticestructureintegrityofthefilms.
简介:Theeffectofsolidificationrateonthemicrostructuredevelopmentofnickel-basedsuperalloyunderthetemperaturegradientof500K·cm-1wasstudied.Theresultsshowthat,withtheincreaseofdirectionalsolidificationratefrom50to800μm·s-1,boththeprimaryandthesecondarydendritearmspacingsofthealloydecreasegradually,andthedendritemorphologiestransformfromcoarsedendritetosuperfinedendrite.Thesizesofallprecipitatesinthesuperalloydecreasegradually.Themorphologyof...
简介:1IntroductionOverthepastfewyears,intensiveworkhasbenmadetoachievemulticolororfulcolorthinfilmelectroluminescence(EL)device...
简介:各向异性的MnBi/NdFeB(0wt%的MnBi内容,20?wt%,40?wt%,60?wt%,80?wt%,并且100?wt%)混合结合的磁铁被用MnBi粉末和再结合(HDDR)NdFeB粉末塑造压缩准备。在房间温度的磁性的大小证明与MnBi内容增加,MnBi/NdFeB混血儿的磁性结合了磁铁都逐渐地减少,当混合磁铁的密度几乎线性地改善时。在293-398的一个温度范围?K,混合磁铁的coercivity温度系数从0.59逐渐地改善?%比较。建模和频率与二低角落频率认为压力消除阀门是一个秒顺序系统是合理的试验性的结果表演。PID控制,死了的乐队赔偿控制和鷸?鷸??
简介:AseriesofPr-CothinfilmsweredepositedontheSi(100)substrateswithCrunderlayerbymagnetronsputtering.Theeffectsofboththepost-annealingtemperatureandtheannealingtimeonthemicrostructureandmagneticpropertiesforthePr-Cofilmswerestudiedsystematically.Theas-depositedPr-Cothinfilmsaremostlyamorphousandtendtocrystallizeafterannealingattemperaturesabove600℃.Whentheannealingtimeisincreased,thefilmsshowacomplicatedstructurewithvariousphasesco-existing.Accordingly,theas-depositedfilmandlowtemperatureannealedfilmsaresoftmagnetsandfilmsannealedattemperaturesbeyond600℃tendtobehardmagnets.Whentheannealingtimeisincreasedfrom5minto2h,thefilmstransferfromhardmagnetstosoftagain.Thesampleannealedat600℃for10minshowsthelargestcoercivityof0.59T.
简介:LiCoO2thinfilms,whichcanbeusedasacathodematerialinmicrobatteries,weredepositedusingradiofrequency(r.f.)magnetronsputteringsystemfromaLiCoO2targetandinanO2+Aratmosphere.ThefilmswerecharacterizedbyvariousmethodssuchasXRD,SEMandAFM.TheLiCoO2filmswereannealedinairat300,500,700and800℃respectively.Theeffectoftheannealingtemperatureonthestructure,thesurfacemorphologyandtheelectrochemicalpropertiesofthefilmswereinvestigated.TheLiCoO2thinfilmdepositedatroomtemperatureisamorphousandhassmallergrainsize.Withincreasingofannealingtemperature,thecrystallinityofthefilmsispromoted.Whentheannealingtemperatureincreasesto700℃,thefilmshaveaperfectcrystallineLiCoO2phase.TheLiCoO2thinfilmwithoutannealinghasnodischargeplateauandsmalldischargecapacity(about27μAh·cm-2μm).Thedischargecapacityincreaseswiththeincreasingofannealingtemperatureandreaches47μAh·cm-2μmforthefilmannealedwith700℃,whichalsoshowsthetypicaldischargeplateauof3.9V.ThecycleperformanceofLiCoO2thinfilmsofasgrownandannealedatdifferenttemperatureswerestudied.Inthecaseofthefilmwithoutthermaltreatment,thecapacityfadingismuchfasterthanthatofthefilmannealedatdifferenttemperature,showingabout40%capacitylossonlyafter25cycles.However,inthecaseofthefilmannealedat700℃,thecapacityreachestosteadystategraduallyandmaintainedconstantlywithcycling.After25timescycling,thedischargecapacityofthefilmannealedat700℃decreasestoabout36.9μAh·cm-2·μm,only0.8%capacitylosspercycle.
简介:ThemicrostructuresandVickershardnessatroomtemperatureofarc-meltingprocessedintermetallicsofMo5Si3-MoSi2hypoeutecticalloyandhypereutecticalloyannealedat1200℃fordifferenttimewereinvestigated.LamellarstructureconsistedofMo5Si3(D8m)phaseandMoSi2(C11b)phasewasobservedinallthealloys.ForMo5Si3-MoSi2hypoeutecticalloy,thelamellarstructurewasfoundonlyafterannealinganddevelopedwellwithfinespacingontheorderofhundrednanometersafterannealingat1200℃for48h.Butwhentheannealingtimewasupto96h,thewell-developedlamellarstructurewasdestroyed.ForMo5Si3-MoSi2hypereutecticalloy,thelamellarstructurewasfoundbothbeforeandafterannealing.Howeverthevolumefractionandspacingofthelamellarstructuredidnotchangesignificantlybeforeandafterannealing.Theeffectsoftheformation,developmentanddestructionoflamellarstructureonVickershardnessofalloyswerealsoinvestigated.WhenMo5Si3-MoSi2hypoeutecticalloyannealedat1200℃for48h,theVickershardnesswasimprovedabout19%comparedwiththatwithoutannealingandformationoflamellarstructure.ThehighestVickershardnessofMo5Si3-MoSi2hypereutecticwasincreasingabout18%whenannealingat1200℃for48h.
简介:IsothermalcompressionofaTi-5.6Al-4.8Sn-2.0ZralloywasconductedonaThermecmaster-Zsimulatoratthedeformationtemperaturesrangingfrom960to1060°C,thestrainratesrangingfrom0.001to10.0s-1,andthemaximumheightreductionof70.0%.Inthetwo-phaseregionoftheTi-5.6Al-4.8Sn-2.0Zralloy,thevolumefractionofαphasedecreaseswithanincreaseindeformationtemperature,butthegrainsizehasaslightvariationwithdeformationtemperature.ThestrainrateaffectsbothmorphologiesandgrainsizeoftheαphaseintheisothermalcompressionoftheTi-5.6Al-4.8Sn-2.0Zralloy.Theoptimalheightreductionalsocontributestothesmallandwell-distributedαphaseintheisothermalcompressionofTi-5.6Al-4.8Sn-2.0Zralloy.
简介:Todevelopanewmagnesiumalloywithexcellentformabilityatroomtemperature,theeffectofY,Ce,andGdadditionontextureandstretchformabilityofMg–1.5Znalloyswascarriedout.TheresultshowsthatY,Ce,andGdadditioninMg–1.5Znalloyscaneffectivelyweakenandmodifythebasalplanetexture,characterizedbyTD-splittextureinwhichthepositionofbasalistitledfromnormaldirection(ND)towardtransversedirection(TD).WhenMg–1.5ZnalloywithGdadditionappearslowtextureintensityandTD-splittexture,wherethepositionofbasalpolesistiltedbyabout±35°fromNDtowardtoTD,thelargestErichsenvalueof7.0andtheelongationratereaches29.1%inTDdirection.However,YandCeadditioninMg–1.5Znalloyspromotealargenumberofsecondphaseparticles,whichcancelthecontributionoftheuniquebasaltexturetostretchformabilityandductility.
简介:Anisotropicpowderwaspreparedwithprecursor(NdDy)-(FeCoNbCu)-Bsinteredmagnetsbyhydrogendecrepitation,desorption,andsubsequentannealingtreatment.Thehydrogendesorptionwasperformedinmagneticfieldsof0,1,3,and5T.Theorientationoftetragonalphasegrainsofthepowderwasevaluatedfromthehysteresisloopsmeasuredbyextractionmagnetometer.Residualhydrogencontentofthepowderwasevaluatedbythermal-magneticanalysis.ThepowderwithHcj,Br,and(BH)maxof1138kA·m-1,1.029T,and172.5kJ·m-3,respectively,wasachievedundertheconditionofthemagneticfieldof3T.Magneticpropertiesofthepowder,especially,theremanenceofthepowder,areenhanceduponmagneticfields,whichisduetobetterorientationofpowderparticlesandlessresidualhydrogeninthepowderresultedfromthemagneticfieldduringthehydrogendesorptionprocess.
简介:Au/-Al2O3催化剂被免职降水方法为低集中白酒溪流(甲醇,乙醇,iso-propanol和n-propanol)的催化燃烧作好准备。催化剂被X光检查光电子描绘光谱学(XPS),X光检查diffractometry(XRD)和精力散X光检查微分析(版本)技术。XPS结果证明仅仅催化剂的表面上有Au0。XRD模式证明Au高度大概在-Al2O3上被驱散。为有2.0g/m3的集中的甲醇,乙醇,iso-propanol和n-propanol的完全的变换的温度是60,155,170和137?,分别地但是他们完全在60,220,260和217点被使矿物化进CO2和H2O吗?分别地在优化催化剂上。催化剂的活动在130h是稳定的。为催化甲醇消除的动力学跟随了伪--首先订表示为r=0.6528c0+0.084的反应2。明显的激活精力的价值是在反应温度的范围的54.7kJ/mol。
简介:TiO2/Au/TiO2多层的薄电影用dc(直接水流)在房间温度在聚合物底层被扔磁控管劈啪作响方法。由改变每层的厚度,TiO2/Au/TiO2多层的电影的光、电的性质能被定制适合不同应用。厚度和Au层的光性质和Au绝缘的接口的质量为Au绝缘的多层的薄电影的电、光的表演是批评的。在8nm的厚度,Au层形成有最低抵抗力和它的连续结构一定为高发射度薄。多层的栈能被优化有6的一个表电阻?在在在波长的680nm的超过80%的发射度的/sq.。当时,山峰发射度向长波长区域变二TiO2的厚度(上面、更低)层增加。当二部TiO2电影的电影厚度是45nm时,高发射度价值为全部可见轻波长区域被获得。