简介:ZM5镁合金上的preplacedAl+红外粉末的激光cladding被执行提高ZM5镁合金的腐蚀抵抗。一冶金契约在涂层/底层接口被获得。激光cladded样品的腐蚀潜力(Ecorr)是对未经治疗的ZM5底层的积极的169mV,当腐蚀电流(Icorr)低大约一个数量级时。激光cladded样品不同于未经治疗的ZM5底层,在极化阴谋显示出一个被动区域。沉浸测试证实激光claddedZM5样品的腐蚀电阻显著地在3.5wt.%NaCl答案被提高。在cladding层和快速的稳固的特征形成的AlIr,Mg17Al12,和艾尔的Al富有的阶段被贡献涂层的改进腐蚀行为。
简介:TheCurietemperatureof(Nd1-xPrx)2Fe14CoyBcompounds(x=0,0.2,…,1.0andy=O,2,4,6,14)hasbeendeterminedwithACinitialsusceptibilitymeasurement.ItwasfoundthatthevariationsofCurietempera-turewithxisnotlinearfory=0and14,whereasitislinearforothervaluesofy.Thelatticeconstantsof(Nd1-xPrx)2Fet14BweredeterminedbyusingX-raydiffraction.Thelatticeexpansionwasmostlyalongthecaxis,whereasthatalongthea-axisremainedpracticallyzeroforthewholeseries.ItissuggestedthatPratomsmayshowsitepreferenceinR2M14Bcompounds(M=FeorCo).DuetothesubstitutionofCoforFe.thetendencyofsitepreferenceofPrbecomeslesspronounced,whichmaybeattributedtothedecreaseofdiffer-enceofcrystalelectricfield(CEF)actingonthetworareearthsiteswiththeintroductionofCoorFe.Incon-trasttothatofthePratoms,thesitepreferenceofCoiu(Nd(1-x)Prx)2Fe(14-y)CoyBcompoundsdoesnotdependonthecompositionoftherareearthsublattice(R=NdorPr).
简介:ThemicrostructureandmagnetostrictivepropertieswereinvestigatedintheTbdopedFe83Ga17-xTbx(x=0.05,0.10,0.20,0.30,0.40,0.50)bulkrodspreparedbymeltrapidlyquenching.ThepartialsolidsolubilityofTbintheFe–GamatrixwaspreliminarydetectedbythelatticeparametersandSEMobservation.ThematrixkeepsA2structureandthesecondphaseappearssurroundthegrainboundaryasxC0.1.h100ipreferredorientationisalsoobservedforx=0.1samplealongtheaxisofthequenchedrod.Thesaturationmagnetostrictionfirstincreasesandmaximumvaluereachesatx=0.1,andthendecreaseswithTbadditionincreasing.TheinitialincreaseofthemagnetostrictionshouldbeassociatedwiththepartialsolutionofTbinthematrix,themaximumvalueatx=0.1shouldbeattributedtotheh100ipreferredorientation,andthedecreaseofthemagnetostrictioniscorrelatedwiththeappearanceofthesecondphasealongthegrainboundary.
简介:Nb-24Ti-18Si-2Al-2Hf-4CrandNb-24Ti-18Si-2Al-2Hf-8Cralloyswerepreparedbyarcmeltinginawater-cooledcrucibleunderargonatmosphere.Microstructuralcharacteristicsandoxidationresistanceofthealloysat1250℃wereinvestigated.Theresultsshowthat,whentheCrcontentis4at%,themicrostructuresconsistof(Nb,Ti)_(ss)andNb_5Si_3;asCrcontentincreasesto8at%,C14LavesphaseCr_2Nbisformed.Theisothermaloxidationtestsshowthattheoxidationkineticsofthetwoalloysfollowsimilarfeatures.Theweightgainsofthetwoalloysafteroxidationat1250℃for100hare235.61and198.50mg·cm~(-2),respectively.Duringoxidation,SiO_2,TiO_2,Nb_2O_5andCrNbO_4areformedatfirst.Then,Ti_2Nb_(10)O_(29)isformedafteroxidationfor20minandbeginstochangeintoTiNb_2O_7astheoxidationproceeds.SiO_2isformedassolidstateatfirstbutlaterevolvesintoglassystatetoimprovethecohesionofthescale.Afteroxidationfor100h,oxidationproductsconsistofSiO_2,TiNb_2O_7,Nb_2O_5andCrNbO_4.
简介:Coppercoatingwasdepositedonthesurfaceofaluminumboratewhiskerbyanelectrolessplatingmethod.Thismethodwasusedtomodifytheinterfacialpropertyofsqueeze-castingaluminumboratewhiskerreinforced6061Almatrixcomposite.Interfaceobservationindicatesthatthespinelreaction(MgAl2O4)ishinderedbythecoppercoating,andthedifferenceininterfacialreactiondegreeaffectsthetensilepropertyandagingbehaviorofthecomposite.Forthecompositewithlessspinelreaction(MgAl2O4),itspeak-agingprocessarepostponedduetolessdepletionofmagnesium.Onthefracturesurfaceofcopper-coatedcompositedimplesandfracturesofwhiskersaremore,butonthefracturesurfaceofuncoatedcompositepull-outofwhiskersaremorethanthatonthecoatedone.Inuncoatedcompositethefracturegenerallyoriginatesfromthenear-interface-region.
简介:通过电化学技术分析镁空气电池阳极Mg-Al-Pb-La合金的放电行为,并与Mg-Al-Pb合金的放电行为进行比较.结果表明,相对于Mg-Al-Pb合金,Mg-Al-Pb-La合金在开路电位下耐蚀性增强,表现出更好的放电活性.Mg-Al-Pb-La合金阳极的利用效率比商用Mg-Al-Zn(AZ)和Mg-Al-Mn(AM)合金阳极的利用效率高.由Mg-Al-Pb-La阳极和空气阴极组成的单个镁空气电池的平均放电电压为1.295V,在放电电流密度为10mA/cm2时其放电容量为1370mA·h/g,比Mg-Li合金作为空气电池阳极时的放电容量高.Mg-Al-Pb-La阳极放电性能的增强是由于显微组织的改变降低了自腐蚀,加速了电池放电过程中氧化产物的脱落.另外,分析了Mg-Al-Pb-La合金阳极在放电过程中的溶解机制.
简介:扔的near-liquidus准备的6061件半固体铝合金化工物品借助于Gleeble-3500热机械的模拟器处于半固体状态被压缩。在在不同温度和紧张率的真压力和真紧张之间的关系与70%的变丑度被学习。微观结构在变丑过程期间被描绘。半固体合金的变丑机制和形成thixo性质被分析。结果证明同类并且6061Al合金由扔技术的near-liquidus生产了的半固体的非树突微观结构能与对与通过再热的最容易溶解的作文在球形附近的谷物和液体阶段镇静的形成thixo合适的微观结构被转变成半固体状态过程。变丑温度和紧张率显著地影响山峰压力而非稳定流动应力。到处于半固体状态的变丑的抵抗随变丑温度的增加和紧张率的减少减少。在稳定的thixotropic变丑舞台,thixotropic性质是一致的,并且主要变丑机制是在稳固的粒子和稳固的粒子的塑料变丑之间旋转或滑动。
简介:AZr-1.15wt%Cr-0.10wt%Fealloywasbeta-quenchedfrom1050℃toproduceasupersaturatedα′-phase,andthenheatedforvaryingtimesattemperaturesfrom650℃to760℃toprecipitateZr(CrFe)2.Athermoelectricpower(TEP)techniqueandtransmissionelectronmicroscopy(TEM)wereusedtomonitorthisprecipitationprocess.UsingtheJohnson-Mehl-Avramiequation,theTEPresultsandalineregressionmethod,theactivationenergyfordiffusionandthediffusioncoefficientofchromium(andFe)inα-Zrhavebeencalculatedover650℃~760℃.Thetemperaturedependenceofthediffusioncoefficient,DCr/α(cm2/s)isdescribedat650℃~760℃bytherelationshipformula.ThecoarseningoftheZr(CrFe)2particlesshowsat1/2dependenceofmeanparticlesizeonagingtime,t.Suchatimedependenceistypicalofcoarseningwhereatomtransferacrosstheinterfaceisrate-controlling.
简介:有软磁性的层(Fe)或antiferromagnetic层(Mn,FeMn或MnO)的各向异性的Pr-Fe-B电影被准备由直流(DC)磁控管在Si(100)底层上劈啪作响在650点加热了?te是由有90的一个方向的热伪造?%塑料变丑。然后,前进状态的微观结构合成被观察,并且机械性质的变化法律和磨擦表演在以后并且在塑料使变形前被比较。结果显示艾尔3增强Zr的粒子旋转并且闯入10-20的更小的尺寸?ng可溶的biopolymer有三个转变金属离子的牛的浆液白朊(BSA)(M,M=Cu,公司,Mn)。白朊一定的金属离子的有约束力的模式和比率被调查。BSA-M建筑群被紫外力的、圆形的二色性(CD)描绘系列和polyacrylamide胶化电气泳动(页)。当聚合物支架和金属建筑群作为催化活跃中心工作了,BSA服务了。当到BSA的转变金属离子建筑群的有约束力的比率是5:1时,结果证明BSA的结构仍然保持未改变。而且,清除superoxide一??
简介:CaTiO3的形成行为在钛铁矿的electro-deoxidization期间专注准备FeTi合金被实验和模拟调查。结果显示中间的产品的形成和分解,CaTiO3,在钛铁矿的electro-deoxidization期间是不可避免的步专注。CaTiO3能在电气化学的过程期间通过熔融的盐和电气化学反应的hydrolyzation被产生。为CaTiO3的产生的主要原因在阴极是在从熔融的盐和TiO2的Ca2+之间的电气化学反应。与electro-deoxidization继续,CaTiO3是进一步的electrolyzed形成钛低值氧化物。当在由在sintering期间增加CaCO3的阴极的CaTiO3形式处理时,当前的效率能被改进。
简介:ThecoercivitymechanismofNd-Fe-Bbasedmagnetspreparedbyanewtechniqueofstripcastingwasinvestigated.Differentfromthetraditionalmagnets,α-FephasesaredifficulttobefoundinNd-Fe-Bmagnetspreparedbystripcasting.Meanwhile,therich-Ndphasesoccurnotonlynearthegrainboundariesofmainphases,butalsowithinthemain-phasegrains.Investigationonthemagnetizingfielddependenceofthecoercivityforthe(Nd0.935Dy0.065)14.5Fe79.4B6.1magnetandthetemperaturedependenceofthecoercivityfortheNd14.5Fe79.4B6.1magnethavebeendone.Resultsshowthatcoercivitiesforstripcastingmagnetsarecontrolledbythenucleationmechanism.
简介:改善高温气冷用石墨抗氧化性能对高温气冷堆安全性具有重要意义。本文利用HSC—CHEMISTRY4.1计算软件分析了SiC涂层、SiO2涂层和SiC/SiO2复合涂层在高温气冷堆正常服役条件和事故条件下的热稳定性,并用氧化试验对热稳定性和抗氧化性能进行了研究。结果表明,SiC/SiO2复合涂层在高温气冷堆正常服役条件和事故条件均能保持长期稳定。在纯氮气及氮气-空气混合气体氧化条件下,SiC/SiO2复合涂层均具有很好的热稳定性,并且能显著改善高温气冷堆用石墨的抗氧化性能。