简介:Highsolid-solubilityCo15Cu35alloyshavebeenpreparedbymeltspinningandsubmittedtoisothermalandanisothermalannealingtoobtaingranularalloys.TheX-raydiffraction(XRD)patternsweremeasuredtoinvesugatethedecompositionofsupersaturatedsolidsolutioninducedbyannealing.Theatomicdiffusionandstructuralevolutionduringtheheattreatmentwereinvestigated.Inviewoftheproblemslimitingtheirappllcation.thehigh-fieldmagneazationcurvesweremeasured.Byafittothehigh-fieldmagnetizationcurves,thegranuiaralloysarefoundhardtobemagneticallysaturatedattheearlystageofnucleationandgrowth.Themagnetizationbehaviorwascorrelacedtotheannealed-inducedstructurealevolutionandalsotothemagnetoresistanceeffect.
简介:利用粉末冶金方法研制了Sm(CobalFe0.24Cu0.08Zr0.027)7.0,Sm(CpbalFe0.27Cu0.05Zr0.027)7.0,Sm(CobalFe0.26Cu0.05Zr0.026)7.03种高温永磁,并对其磁性能、温度稳定性和显微结构进行了分析.结果表明:样品Sm(CobalFe0.27Cu0.05Zr0.027)7.0具有最高的内禀矫顽力(2165.6kA·m-1)和最大磁能积(212.0kA·m-3);3种磁体的温度系数都较低,最高使用温度均在400℃以上,大大高于一般商用磁体;增加Sm,Co,Cu的含量和减少Fe的含量可以提高材料的温度稳定性.X射线分析表明,合金中含有Sm2(Co,Fe)17主相,Sm(Co,Cu)5相,含Zr化合物等.Sm(Co,Cu)5相、单质Zr、晶粒边界等钉扎畴壁,使合金具有较高的矫顽力.
简介:ElectrolyticfixationofCO2wasinvestigatedbyelectrocarboxylationoforganichalides(RX),andfourestersⅠ,ⅡⅢ,Ⅳ)wereobtainedinmoderateyields.ElectrochemicalreductionesterificationsofRXinthepresenceofCO2werecarriedoutonnanocry'stallineTiO2-Ptelectrode.TheelectrochemicalbehaviorofRXinthepresenceofCO2wasinvestigatedbythetechniqueofcyclicvoltammetry,andtheprobablereactionmechanismw,asproposed.
简介:Muchattentionhasbeenpaidtothedevelopmentofnewpolymerelectrolytewithspecialmorphology,soastoimprovetheirelectrochemicalpropertiestomeettheneedsoflithium(ion)battery.Inthiswork,PEMlatexwassynthesizedbyemulsion-fi-eepolymerization.ThemicrophotoofPEMlate...
简介:Thetungsten-inert-gas(TIG)arcweldingexperimentsofcementedcarbideYG30andsteel45werecarriedoutusingtheNi-Fe-Cfillingalloys.Theetaphasesandmechanicalpropertiesofweldedjointswereanalyzedbymeansofscanningelectronicmicroscope(SEM),transmissionelectronicmicroscope(TEM)coupledwithselecteddiffraction,electronicprobemicroanalysisandbendingstrengthmethods.Theexperimentalresultsshowthatthechemicalcompositionofthefillingalloysaffectsetaphaseformation.Whenthecarbonandnickelcontentsinfillingalloysare0.61wt%and55.29wt%,respectively,noetaphasesform.Andthejointbendingstrengthisthehighestto1.352GPa.Butiftheyare0.01wt%and55.38wt%,theetaphasesareformedattheboundariesofthecementedcarbideandtheweld,andthethicknessofetaphaselayerisabout110micrometers.Andthejointbendingstrengthislow.Usually,theseetaphasesareanomalouslygranular,andeasytoaccumulateattheboundariesbetweencementedcarbidesandtheweld.TheyaremultipleM6Crichintungstenandiron.
简介:Thermodynamiccalculation,SEM(scanningelectronmicroscopy),TEM(transmissionelectronmicroscopy),XRD(X-raydiffraction),phaseextraction,andchemicalanalysiswereemployedtostudythephasestabilityandphaseprecipitationinanewNi-Cr-Cobasesuperalloyheat-treatedat704and760℃foralongtime.Theresultsshowthattheprecipitatesofthisnewalloyheat-treatedatstandardannealingconditionandheat-treatedat704and760℃foratimeupto2000hareγ′,MC,M23C6,andM6C,andηphaseformsatgrainboundariesandinmatrixofsamplesheat-treatedat760℃aswell.Themassfractionsofγ′(+η),MC,M23C6,andM6Cinallsampleshavenolargechangeswithanincreaseinagingtime,butγ′precipitatesgrowobviously.Theγ′-to-ηtransformationinthesamplesheat-treatedat760℃tookplacewithincreasingagingtime.TheηprecipitatesformaWidmanstattenpattemandtheγ′phaseshaveremeltedpartlyinthesamplesheat-treatedat760℃.Thealloymaintainsabettermicrostructuralstabilityduringprolongedagingat704℃,butaworsemicrostructuralstabilityduringprolongedagingat760℃.