简介:BasedontheMiedemamodelandExtendedMiedematheory,theformationenergiesofdifferentsolutecomponentsinEr-XbinarysystemandAl-Er-Xternarysystemswerecalculated.TheresultsshowthatthevariationoferbiumcontenthaslittleinfluenceonthechancerateoftheformationAl-ErcompoundintheAl-Mg-Mn-Zr-Ersystem.ThecalculatedformationenergiesintheEr-XbinarysystemandAl-Er-XternarysystemsindicatethatAl3Erphasecantakepriorityofdepositing,Al-Er-Zrternarycompoundsmayalsofoundwhichagreeswiththeexperimentalresultsinreferences.TheconsistencyofcalculationandexperimentprovesthattheintermetalliccompoundsintheAl-Mg-Mn-Zr-ErsystemcanbepredicteddirectlybycalculatingtheformationenergiesofthereactionsinEr-XbinarysystemandAl-Er-XternarysystemswiththeMiedemamodelandExtendedMiedematheory.
简介:将合成的假乙内酰硫脲酸(PGA)用作铜-钼分离抑制剂。该药剂闭路实验结果表明:假乙内酰硫脲酸在较小的用量下对黄铜矿有较强的抑制作用,经一次粗选、一次扫选、两次精选,可获得Mo品位大于26%、回收率大于89%的浮选指标,而用Na2S做抑制剂时钼的回收率下降了2%。药剂吸附量测试结果表明,PGA与丁基黄药在矿物表面发生竞争吸附,PGA在黄铜矿表面上的吸附量远大于在辉钼矿表面的。红外光谱分析表明,PGA在黄铜矿表面是化学吸附,而在辉钼矿表面属于物理吸附。前线轨道计算结果表明,在PAG分子中,硫原子是反应活性的中心。利用矿物、丁黄药及PGA的费米能级能量大小可以从电化学作用角来度解释PGA的抑制机理。
简介:X-rayDouble-crystalDiffractometerwithHorizontalSlitsandItsApplicationsXuJingyangandZhuNanchang徐景阳,朱南昌(ShanghaiInstituleofMeta...
简介:MgTixNi(x=0,0.1,and0.2)alloysweresuccessfullypreparedbymechanicalalloying(MA),andtheinfluenceofmillingtimeontheelectrochemicalcharacteristicsoftheelectrodeswasdiscussed.MgTixNialloysafter90hmillingdisplayedthebestelectrochemicalperformance.TheX-raydiffractionpatternsshowedthatthealloyball-milledfor90hwasamorphouswithawideneddiffractionpeak.Thecharge-dischargetestsindicatedthatthesealloyshadgoodelectrochemicalactivationproperties,andtheMgTi0.2Nialloyelectrodeexhibitedthebestcycleperformance.TheinitialdischargecapacityoftheMgTi0.2Nialloyreachedupto401.1mAh·g-1,andtheretentionrateofcapacitywas31.0%after30cycles,muchhigherthanthatofMgNi(17.3%).TheTafelpolarizationcurvesrevealedthatTiadditioncouldenhancetheanticorrosionperformanceofthesealloysinalkalisolution,whichwasresponsiblefortheamelioratedcyclicstabilityofthesealloyelectrodes.
简介:X-raydiffraction(XRD)anddifferentialscanningcalorimetry(DSC)wereusedtoinvestigatethecrystallizationprocessofamorphousAl90TMxCe10-x(atomfractionin%;TM=FeorNi;x=3,5)alloys.AgingeffectswereexaminedbyX-raydiffraction.ThestructurecorrespondingtotheprepeakfortheamorphousAl90Fe5Ce5alloyismorestablethantheamorphousmatrix,butitisnotstableforamorphousAl90Ni5Ce5alloyduringthefirstcrystallizationstageandevendecomposesatroomtemperature.AlthoughbothAl-NiandAl-Fehavestrongchemicalbonding,thecrystallizationonsettemperatureofamorphousAl-Fe-CealloysismuchhigherthanthatofamorphousAl-Ni-Cealloys,whichislikelycausedbythedifferentstabilityofthestructurecorrespondingtotheprepeak.ThecrystallizationonsettemperatureincreasesasCe/NiratioincreasesinamorphousAl90NixCe10-xalloys,whereasitdecreasesasCe/FeratioincreasesinamorphousAl90FexCe10-xalloys.AbetteratomicpackingproducesasCecontentincreasesbecauseofthesizemismatchinAlNi-CesystemsandasFecontentincreasesbecauseoftheincreasingFecentralstructuralunits.
简介:Anewseriesofrareearthcompounds,Y2-xErxMo4O15(x=0.0-2.0),weresynthesizedandtheirstructuresweredeterminedbypowderX-raydiffraction(XRD).RietveldanalysisofXRDpatternsrevealsthatthecompoundsofthisseriescrystallizeinmonoclinicsystemwithspacegroupP21/c.Thelatticeparametersa,b,c,βandtheunitcellvolumeVde-creaselinearlywithincreasingErcontent.Thethermalexpansionpropertiesofthesecompoundswerestudiedunderhigh-temperatureXRD.PositivethermalexpansionsofcompoundsY2-xErxMo4O15arefoundtobeanisotropicalongthethreecrystallographicdirectionswhereaandcaxesexpandwhilebaxiscontractsinthewholetemperaturerange.Byanalysisofdata,theexpansionofweakbandMo2-O14withrisingtemperatureshouldberesponsibleforpositivethermalexpansion.
简介:Mgx(Ti0.9Zr0.2Mn1.5Cr0.3)(x=20%,30%,40%)(集体部分)合成粉末被反应的球milling与氢和他们的氢存储性质准备,微观结构被XRD,SEM和pressure-composition-temperature调查测量。结果证明composites在553K和好加氢动力学有3.83%-5.07%氢能力,甚至在房间温度。在他们之中,milledMg-30%(Ti0.9Zr0.2Mn1.5Cr0.3)合成当它能快速在373K吸收2.1%氢,有最高的加氢动力学,3.5%在在473K的2000s,在3MPa氢压力下面在553K在60s弄平3.26%。改进加氢性质来自粒子在Mg粒子的表面上一致地驱散的Ti0.9Zr0.2Mn1.5Cr0.3的催化效果。
简介:PolycrystallinesamplesofLa12x(Sr12yAgy)xMnO3(y=0.0,0.2,0.4,0.6,1.0)werepreparedbythesolid-statereactionmethod.ThetemperaturestabilityofmagnetoresistanceandmagnetoresistanceenhancementinLa1-x(Sr1-yAgy)xMnO3systemwithbothunivalentandbivalentelementsdopedatAsiteandwithunchangedvalueofMn3+/Mn4+ratiowereexploredthroughthemeasurementsofX-raydiffractionpatterns,magnetiza-tion-temperature(M-T)curves,resistivity-temperature(q-T)curvesandmagnetoresistance-temperature(MR-T)curves.Theresultsareasfollows:therearetwopeaksintheq-TcurvesofthesampleswithAgdoping,oneiscausedbyresistancechangeduringtheparamagnetism-ferromagnetismtransition,andtheotherisfromboundary-dependentscatteringofconductionelectronsontheboundariesofgrains.ThepeakvalueofMRincreaseswithincreasingAgdopingcontent,anditincreasesfrom8.2%fory=0.2to29.6%fory=1.0underthemagneticfieldofB=0.8T;MRremainsaconstantof12%inthetemperaturerangeof218-168Kforthesamplewithy=1.0,andthetemperaturestabilityofMRisinfavorofthepracticalapplicationofMR.
简介:TheagingbehaviorofAl-Cu-Mg-AgalloyswithhighCu/Mgwasstudiedbytransmissionelectronmicroscopy(TEM)andsmall-angleX-rayscattering(SAXS)usingsynchrotronradiation.TEMstudyrevealsthatthemajorstrengtheningphasesofthealloyafteragingat160?Cfor10hareΩandlessθ′.SAXSstudyshowsthatthescatteringpatternsarecomposedofseveralconcentriccirclesatthebeginningofagingprocess,whichisreplacedbythebutterfly-wingsscatteringpatternswiththeincreaseofagingtime...
简介:采用SEM、TEM、EDS、DSC、XRD和拉伸实验研究铸态7X50合金及其均匀化处理过程的组织演变。结果表明,铸态7X50合金相组成主要有S(Al2CuMg)、T(Al2Mg3Zn3)、MgZn2和少量的Al7Cu2Fe和Al3Zr相。均匀化处理过程中枝晶网和残留相逐渐减少,经(470°C,24h)+(482°C,12h)均匀化处理时,T相消失,S相有微量残留,Al7Cu2Fe相几乎没有变化。铸态合金的DSC曲线中在477.8°C处有一较强吸热峰,经470°C、1h均匀化后合金的DSC曲线在487.5°C处出现一个新的吸热峰,而经482°C、24h均匀化处理后合金在487.5°C处的吸热峰基本消失。在XRD谱中未出现T(Al2Mg3Zn3)相,这和T相与S(Al2CuMg)及MgZn2相相关的结论相吻合。预均匀化处理制备的板材中再结晶晶粒分数明显降低,抗拉强度和断裂韧性相对常规均匀化处理制备的板材分别提高约15MPa和3.3MPa·m1/2。