简介:采用化学镀法对TiH2粉末表面镀Ni,制备Ni/TiH2复合粉末。通过X射线衍射(XRD)、扫描电镜(SEM)、能谱分析(EDS)及差热分析(DSC/TG)对Ni/TiH2复合粉末进行表征,探索Ni镀层的生长及作用机理,建立镀层在粉末表面的生长模型。结果表明:施镀温度为85℃时Ni/TiH2复合粉末表面Ni层包覆完整,镀层均匀致密,Ni层厚度约为1.0~2.0μm;施镀温度低于65℃时施镀几乎无法进行,而施镀温度高于95℃时,镀层很不均匀,且容易脱落;镀层的生长机制遵循奥斯特瓦尔德(Ostwaldripening)机制;与包覆前TiH2粉末相比,Ni/TiH2复合粉末的释氢反应开始温度由450℃上升至540℃。包覆层可降低TiH2粉末和熔融铝的温度梯度,从而推迟开始释氢的时间。
简介:将空心微珠在HF和NaF的缓冲液中进行粗化处理,然后用75℃热碱液活化,再以甲醛为还原剂,在空心微珠表面化学镀银。通过扫描电镜(SEM),X射线能量色散谱仪(EDS)和X射线衍射(XRD)对所得复合粉体的表面形貌、成分以及镀层与空心微珠的结合强度进行研究与分析,并探讨pH值对沉积效果的影响。结果表明:粗化处理可增大空心微珠的表面粗糙度,从而提高Ag+的形核能力,所得镀层完整、致密。镀液pH升高,包裹层更完整、致密,且银层增厚。在pH=12.9的条件下,可实现银层对空心微珠均匀、致密的包裹,得到镀层结合强度较高、银层较厚、银晶粒尺寸为23.3nm的银包空心微珠复合粉体。
简介:用正交试验法研究了还原法热浸镀中合金主要成分铝、硅含量,浸镀温度、保温时间、钢带入水温度等对镀层附着强度、微观组织、表面质量、浸镀效果(漏镀情况)的影响,得出获取良好镀层质量的最佳工艺条件和参数。
简介:Cr2O3-formingferriticstainlesssteelshavebeenwidelyexploredasintermediatetemperaturesolidoxidefuelcells(SOFCs)interconnects.However,theevaporationofchromiascalemightmigratetoandpoisonthecathode,leadingtodegradationofthecellperformance.Inthisstudy,Ni-Co-Fe-Pcoatingsweredepositedontheferriticstainlesssteelbymeansofacost-effectivetechniqueofelectrolessmethod.Theyareexpectedtobeconvertedinto(Ni,Co,Fe)3O4spinelwithahighelectricalconductivityandCTEmatchwithstainlesssteel,whichcanblocktheevaporationofchromiaformedonsteelsubstrateexposedtothecathodeenvironmentoftheSOFC.TheeffectsofpH,massratioofFeSO4/(FeSO4+NiSO4+CoSO4)andtemperatureofsolutiononthedepositionrate,compositions,surfacemorphologiesandstructuresoftheNi-Co-Fe-Pcoatingswereinvestigated.TheresultsindicatedthatthedepositionrateincreasedwithincreasingpHwhenpHwaslowerthan9andthenreducedwhenpHwashigherthan9.Thedepositionrateincreasedwithincreasingtemperaturewhentemperaturewaslowerthan80℃andthendecreasedwhentemperaturewashigherthan80℃.ThedepositionratedecreasedwiththeincreaseinmassratioofFeSO4/(NiSO4+CoSO4+FeSO4).ThecoatingsconsistedofNi,Co,FeandP.Thephasestructureofthecoatingwasamorphous.
简介:对Cu-W-Ni-C与Ag-ZnO10触头材料的性能进行了对比和研究.在相对密度相同时,CuW-Ni-C材料的电阻率与Ag-ZnO10材料的电阻率接近,而硬度高于Ag-ZnO10材料的硬度.温升和通断能力试验结果表明:Cu-W-Ni-C材料在电力机车电器上完全可替代Ag-ZnO10材料.
简介:本文着重介绍了ZnA1REMg四元热镀合金在手工镀锌行业的应用情况,提出了该合金在手工浸镀时的理想工艺参数,并进一步闸明:ZnA正REMg合金镀层较纯锌镀层减薄1/3,抗蚀性能较单一锌镀层提高1-2倍。
简介:ThehotductilityofFe-36NiinvaralloywithdifferentadditionsoftheelementceriumwasinvestigatedusingaGleeble-3800thermal-mechanicalsimulatoroverthetemperaturerange850-1050℃,andtheimprovementmechanismofthehotductilitywasanalyzedusingacombinationofSEM,EDS,andOM.TheresultsindicatedthatFe-36Niinvaralloyexhibitedpoorhotductilitybelow1050℃,whichwasmainlyattributedtoweakgrainboundariesandtheactionofgrainboundarysliding.However,thealloyswithceriumcontentsof0.016%and0.024%bothdemonstratedsubstantialimprovementinthehotductilityovertheentiretestingtemperaturerange.Theobservedimprovementofthehotductilityofthealloywith0.016%ceriumat950℃andthealloywith0.024%ceriumat900℃wasassociatedmainlywiththegrainboundarystrengtheningandtherestrictionofthegrainboundaryslidingbecausetheadditionofceriumreducedthesegregationofsulfuratgrainboundariesandrefinedthegrainstructure.Theoccurrenceandaccelerationofdynamicrecrystallizationwerefoundtoberesponsibleforthehighhotductilityofthealloywith0.016%ceriumat1000℃andthealloywith0.024%ceriumat950-1000℃asaresultoftherefinementofthegrainstructurebyadditionofcerium.
简介:以金属铜箔和镍粉为原料,采用涂覆法制备出Ni—Cu多孔薄膜。采用场发射扫描电子显微镜(FE-SEM)、x射线衍射仪(XRD)、原予力显微镜(AFM)等设备对所制Ni-Cu薄膜的显微结构、物相组成进行表征。通过压泡法对所制多孔薄膜的通量及孔径进行测试,并探讨薄膜的成孔机理。研究表明:所制备Ni-Cu多孔薄膜厚度约为50μm,平均孔径约10girl;涂覆面通过Ni粉的松装烧结形成多孔结构;铜箔一测的孔是由于Kirkendall效应所产生的空位沿着晶界扩散在表面聚集而成。
简介:TheeffectofCe,LaandmischmetalonthesolidificationstructureofFe-36Niinvaralloywasinvestigated.Theresultsshowthatgreatamountsofhigh-meltingpointcompounds(Ce2O3,La2O2Sand(Ce,La)2O2S)respectivelyformedinthealloywiththeadditionofCe,Laormischmetal.Basedonthetheoryoflatticemisfit,thelatticemisfitbetweenthe(0001)surfacesofCe2O3,Ce2O2SandLa2O2Sand(100)surfaceofFe-36Niinvaralloywere6.21%,5.77%and5.42%,respectively,whicharerelativelylow.Therefore,Ce2O3,La2O2Sand(Ce,La)2O2Scouldserveasthecoreofheterogeneousnucleation,improvetheequiaxedgrainratio,reducetheequiaxedgrainsizeandrefinethesolidificationstructureofalloy.
简介:Ni-Cr-Mo合金经冷压成型后于真空中以不同温度进行烧结.通过测定其相对密度、线收缩率、拉伸强度和硬度,研究烧结温度对合金性能的影响.研究结果表明:当烧结温度不超过1330℃时,合金的相对密度、收缩率、拉伸强度和硬度随烧结温度的上升而缓慢增加;当温度上升到1360℃时,合金的这些性能指标急剧增大;当温度上升到1390℃时,烧结后的合金试样外形发生严重变形.
简介:Inrecentyears,manyNi-containingmaterialsmanufacturedfromlateritehaveplayedasignificantroleinsupportingtherapiddevelopmentofthestainlesssteelindustryinChina.Currently,pyrometallurgyisthemainprocessforlateritesmelting,whereblastfurnacesareemployedtomakeNi-containinghotmetal.Withtheaimofgivingsomereferencesformakinggooduseoflaterite,technicalandeconomicanalysiswasconductedinthispaper,basedonthediscussionofthekeytechnologiesofNi-containinghotmetalproductionwithlaterite(50.4%Fe)inblastfurnaces.
简介:Differentrareearth(RE=La,Ce,Pr,Nd,Sm,Y)andCumodifiednickelcatalystsforhydrogenproductionfrommethanedecompositionweresynthesizedbyasol-gelprocessandmethod.ThecatalystswerecharacterizedoranalyzedthroughBrumauer-Emmett-Teller(BET),X-raydiffraction(XRD),scanningelectronmicroscopy(SEM),transmissionelectronmicroscopy(TEM)techniques.Andthehydrogenproductionperformancewasalsoevaluatedbyafixed-bedandmicro-reactiontechniquewithCH4→C+H2asaprobereaction.Theresultsshowedthatrareearthmodificationhadplayedagreatrolefornickelcatalysts,forexample,smallernickelparticles,goodthermalstability,highactivity,etc.Lawasthebestadditiveamongrareearthmodification.TheSEMofrareearthmodifiedcatalystsshowedorderedflower-likestructureandrareearthmodificationmadethenickelparticlesmovetothesurfaceofcatalysts.Inaddition,theSEMofnano-carbonswasalsochangedbyrareearthmodificationwithlong,narrownano-carbonfibersortubesobtained.Solidcarbonformationwaspreventedbyrareearthmodification.
简介:MeltspinningtechnologywasusedtopreparetheMg2Ni-type(Mg24Ni10Cu2)100–xNdx(x=0,5,10,15,20)alloysinordertoobtainananocrystallineandamorphousstructure.TheeffectsofNdcontentandspinningrateonthestructuresandelectrochemicalhydrogenstorageperformancesofthealloyswereinvestigated.ThestructurecharacterizationsofX-raydiffraction(XRD),transmissionelectronmicroscopy(TEM)andscanningelectronmicroscopy(SEM)linkedwithenergydispersivespectroscopy(EDS)revealedthattheas-spunNd-freealloydisplayedanentirenanocrystallinestructure,whereastheas-spunNd-addedalloysheldananocrystallineandamorphousstructureandthedegreeofamorphizationvisiblyincreasedwiththerisingofNdcontentandspinningrate,suggestingthattheadditionofNdfacilitatedtheglassformingoftheMg2Ni-typealloy.TheelectrochemicalmeasurementsindicatedthattheadditionofNdandmeltspinningimprovedtheelectrochemicalhydrogenstorageperformancesofthealloyssignificantly.Thedischargecapacitiesoftheas-castandspunalloysexhibitedmaximumvalueswhenNdcontentwasx=10,whichwere86.4,200.5,266.3,402.5and452.8mAh/gcorrespondingtothespinningrateof0(As-castwasdefinedasthespinningrateof0m/s),10,20,30and40m/s,respectively.Thecyclestability(S20,thecapacitymaintainrateat20thcycle)oftheas-castalloyalwaysrosewiththeincreasingofNdcontent,andthoseoftheas-spunalloysexhibitedthemaximumvaluesforNdcontentx=10,whichwere77.9%,83.4%89.2%and89.7%,correspondingtothespinningrateof10,20,30and40m/s,respectively.