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41 个结果
  • 简介:采用XAFS研究不同制备条件下超细Ni-P非晶态合金Ni原子配位环境周围的局域结构。结果表明在pH小于11的条件下,样品的非晶化程度随pH的减小而增大;当pH为14时,样品中Ni的区域环境结构与金属Ni的相近。不同退火温度样品的XAFS结果表明,在300℃的温度下退火,超细Ni-P非晶态合金基本晶化生成晶态物相。

  • 标签: XAFS 化学还原法 超细Ni-P非晶态合金 镍磷合金 催化剂 局域结构
  • 简介:采用EXAFS详细研究了系列Ni-Co-B非晶态合金催化剂的结构,结果表明:非晶态Ni-Co-B合金中的金属和非金属之间是一种共价化学键,Co的加入增加了Ni-B非晶态合金的无序度,而B含量的变化对Co-B、Ni-B配位有不同的影响,当样品中Ni、Co含量相同时,存在着协同作用。

  • 标签: Ni-Co-B合金 非晶态合金催化剂 EXAFS 协同作用 结构
  • 简介:采用XAPS和XRD研究Ni-Ce-B超细非晶态合金在退火过程中的结构变化。实验结果表明,在573K的返火温度下,样品仍然保持非晶态结构,仅有少量晶态Ni3B生成;在673K退火温度下、Ni-Ce-B样品晶化生成晶态Ni3B和纳米晶Ni;在773K和更高的温度退火处理后,还有一部分Ni3B并未分解,少量的Ce掺杂使得样品晶化生成的Ni晶格有较大畸变。说明0.3%的Ce对提高Ni-Ce-B样品的稳定性有显著作用。

  • 标签: Ni-Ce-B超细非晶态合金 结构 XAFS 催化活性 催化剂 镍铈硼合金
  • 简介:本文采用XAFS、XRD、DTA三种方法研究化学还原法制备的NiB超细非晶态合金在退火过程中的结构变化及结构与催化性能的关系。XRD和XAFS结果表明,NiB超细非晶态合金的退火晶化过程分两步进行,在325℃的退火温度下,NiB超细非晶态合金晶化生成纳米晶Ni和NiB亚稳物相;在380℃或更高的退火温度下,绝大部分Ni3B进一步晶化分解生成金属Ni物相,其产物中Ni的局域环境结构与金属Ni箔的基本一致。我们发现纳米晶Ni比超细Ni-B非晶态合金或晶态金属Ni粉末有更好的苯加氢催化活性。

  • 标签: 退火晶化 催化性能 XAFS XRD DTA 超细Ni-B非晶态合金
  • 简介:TheNi-AlalloycontainingCr,FeadditiveswerepreparedasRaneyNiCatalystbyhighenergymilling.ThesizeandsurfacestateofNi-Alalloypowderwerestudiedbyparticlesizeanalyzerandsanningelectronmicroscopy.theStructurewasanalyzedbyXRDandMoessbauermethods.Theresultsshowedthatafterahigh-energymilling(HEM).theNi-Alalloytransformstoanano-scaleNiAlstructurewithrichAl.Byannealingthealloy,ametastableNi2Al3phasecanbeobtained.

  • 标签: 催化剂 催化剂镍 纳米晶体
  • 简介:Inordertotransfertheheatfromthearmortothecoolant,tungstenhastobeconnectedwithacopperheatsink.Thejointtechnologyisthemostcriticalissueformanufacturingplasmafacingcomponents.Consequently,thereliabilityofthejointsshouldbeverifiedbyagreatnumberofhigh-heat-flux(HHF)teststosimulatetherealloadconditions.W/CubrazedjointtechnologywithsliverfreefillermetalCuMnNihasbeendevelopedatSouthwesternInstituteofPhysics(SWIP).Screeningandthermalfatiguetestsofonesmall-scaleflattileW/CuCrZrmockupwereperformedona60kWelectron-beamMaterialtestingscenario(EMS-60)constructedrecentlyatSWIP.Themodulesuccessfullysurvivedscreeningtestwiththeabsorbedpowerdensity(Pabs)of2MW/m2to10MW/m2andthefollowing1000cyclesatPabsof7.2MW/m2withouthotspotsandoverheatingzonesduringthewholetestcampaign.MetallurgyandSEMobservationsdidnotfindanycracksatbothsidesandtheinterface,indicatingagoodbondingofWandCuCrZralloy.Inaddition,finiteelementsimulationsbyANSYS12.0underexperimentalloadconditionswereperformedandcomparedwithexperimentalresults.

  • 标签: 铜散热器 钎焊技术 高热流密度 样机 热疲劳试验 铬锆铜合金
  • 简介:Inthisstudy,tungsten(W)wascoatedonacopper(Cu)substratebyusingdouble-glowdischargetechniqueusingapureWpanelasthetargetandargon(Ar)asthedischargeandsputteringgas.ThecrystalstructureoftheWcoatingwasexaminedbyX-raydiffraction(XRD).Scanningelectronmicroscopy(SEM)wasperformedwithcross-sectionimagestoinvestigatethepenetrationdepthofWintotheCubody.Additionally,thepropertiesofwearabilityresistance,corrosionresistanceandmechanicalstrengthoftheWcoatedCumatrixwerealsomeasured.Itisconcludedthatindouble-glowplasma,WcoatedCucanbefacilelyprepared.ItisnoticedthatthetreatmenttemperatureheavilydominatesthepropertiesoftheW-Cucomposite.

  • 标签: 辉光离子 钨涂层 电铜 W-CU复合材料 扫描电子显微镜 表征
  • 简介:Chemicalvapordeposition-tungsten(CVD-W)coatingcoveringthesurfaceoftheplasmafacingcomponent(PFC)isaneffectivemethodtoimplementthetungstenmaterialasplasmafacingmaterial(PFM)infusiondevices.ResidualthermalstressinCVD-Wcoatingduetothermalmismatchbetweencoatingandsubstratewassuccessfullysimulatedbyusingafiniteelementmethod(ANSYS10.0code).Thedepositionparametriceffects,i.e.,coatingthicknessanddepositiontemperature,andinterlayerwereinvestigatedtogetadescriptionoftheresidualthermalstressintheCVD-Wcoating-substratesystem.AndtheinfluenceofthesubstratematerialsonthegenerationofresidualthermalstressintheCVD-WcoatingwasanalyzedwithrespecttotheCVD-WcoatingapplicationasPFM.ThisanalysisisbeneficialforthepreparationandapplicationofCVD-Wcoating.

  • 标签: 面向等离子体材料 残余热应力 表面涂层 热应力分析 面对等离子体材料 化学气相沉积
  • 简介:TheaccumulationofHeonaWsurfaceduringkeV-Heionirradiationhasbeensimulatedusingclusterdynamicsmodeling.Thisisbasedmainlyonratetheoryandimprovedbyinvolvingdifferenttypesofobjects,adoptingup-to-dateparametersandcomplexreactionprocesses,aswellasconsideringthediffusionprocessalongwithdepth.Thesenewfeaturesmakethesimulatedresultscompareverywellwiththeexperimentalones.Theaccumulationanddiffusionprocessesareanalyzed,andthedepthandsizedependenceoftheHeconcentrationscontributedbydifferenttypesofHeclustersisalsodiscussed.TheexplorationofthetrappinganddiffusioneffectsoftheHeatomsishelpfulinunderstandingtheevolutionofthedamagesinthenear-surfaceofplasma-facingmaterialsunderHeionirradiation.

  • 标签: 表面等离子 动力学建模 积累 群集 电子 辐射
  • 简介:采用水热合成法制备了Ni/CeO2-ZrO2-A12O3催化剂。进行了添加和不添加水蒸气的CH4-CO2催化重整反应,测量了积碳量,并用EXAFS手段测试了催化剂Ni的K吸收边。结果表明,反应前后最近邻NiNi配位距离无明显变化,而配位数却变化明显。无水蒸气反应后Ni-Ni配位数有较大幅度的减少,而添加了水蒸汽,NiNi配位数比反应前减少幅度小。水蒸气的添加能减少积碳量,稳定催化剂中Ni的结构,从而提高催化反应的稳定性。

  • 标签: 水蒸气 CH4 CO2 Ni/CeO2-ZrO2-A12O3催化剂 水热合成法 EXAFS
  • 简介:本文扼要介绍了光束线真空控制保护系统的设计思想、设计要求、系统的作用和某些改进。此外,系统在设计了上采用了新技术-可编程序控制器(PLC),使控制系统的可靠性和灵活性得到了进一步的提高。研制这个系统的主要目的是,当光束线上出现(由铍窗或波纹管等偶然破裂引起的)灾难性真空事故时,能够有效地保护北京正负电子对撞机中的大型超高真空装置-电子储存环的真空系统不会遭到这种灾难的破坏,使其安全运行。本光束线的真空控制保护系统于1996年投入试运行,于1998年年底通过院级鉴定和验收。

  • 标签: BSRF 3W1光束线 真空控制保护系统 储存环
  • 简介:CO2adsorptiononthesurfaceofhydrotalcite-derivedmixedoxidecatalystswasinvestigatedunderlowpressureglowdischargeplasmainopercindoconditionsviaFT-IRspectroscopy.Nickelcatalystswerepromotedwithvarioustransitionmetalspecies(Ce,Fe,La,Zr)toinfluencetheirphysico-chemicalproperties.FeandZrspeciesweresuccessfullyincorporatedintohydrotalcitebrucitelayers.AftercalcinationformedasinglephasewithNi(Mg,A1)Omixedoxide,whileLaandCespeciesformedseparatephases.ThishadaconsequenceinthedistributionofsurfacebasicsitesaswellasintheaffinitytoCOproduceduponCO2dissociationinplasma.Plasmatreatmentactivatedthesurfaceofpreparedmaterialsandchangedtheirpropertiesviathegenerationofstrongbasicsitesassociatedwithlowcoordinatedsurfaceoxygenanions.Moreover,theCO2adsorptioncapacityofpreparedmaterialsincreasedafterplasmatreatment.

  • 标签: plasma GLOW DISCHARGE BASICITY HYDROTALCITE carbon