低C高純LaNi5合金制備與提純研究低C高純LaNi5合金制備與提純研究

摘要：

本文以LaNi5合金為研究對(duì)象，通過(guò)多種方法制備低C高純的LaNi5合金，包括球磨法、化學(xué)共沉淀法、真空感應(yīng)熔煉法等，采用X射線衍射、掃描電子顯微鏡和能量色散X射線分析等手段進(jìn)行材料表征和分析。實(shí)驗(yàn)結(jié)果表明，球磨法制備的LaNi5合金的晶粒尺寸較小，化學(xué)共沉淀法制備的LaNi5合金的純度稍低，真空感應(yīng)熔煉法制備的LaNi5合金的崩裂溫度較高。針對(duì)化學(xué)共沉淀法制備的低C高純LaNi5合金進(jìn)行了壓縮成型和真空熱解，制備的LaNi5合金具有良好的結(jié)晶性和電化學(xué)性能，表觀密度達(dá)到99.5%以上。本研究對(duì)于LaNi5合金在氫儲(chǔ)存和氫化動(dòng)力應(yīng)用領(lǐng)域中的應(yīng)用具有一定參考價(jià)值。

關(guān)鍵詞：

低C高純LaNi5合金；制備；提純；壓縮成型；真空熱解

Abstract:

Inthispaper,LaNi5alloywastakenastheresearchobject,andlowChighpurityLaNi5alloywaspreparedbyvariousmethods,includingballmilling,chemicalco-precipitation,andvacuuminductionmelting,etc.ThecharacterizationandanalysisofthematerialwerecarriedoutbyX-raydiffraction,scanningelectronmicroscopyandenergydispersiveX-rayanalysis.TheexperimentalresultsshowthatthegrainsizeofLaNi5alloypreparedbyballmillingissmaller,thepurityofLaNi5alloypreparedbychemicalco-precipitationisslightlylower,andtheLaNi5alloypreparedbyvacuuminductionmeltinghasahigherbrittlenesstemperature.ForthelowChighpurityLaNi5alloypreparedbychemicalco-precipitation,compressionmoldingandvacuumpyrolysiswerecarriedout,andtheLaNi5alloypreparedhasgoodcrystallinityandelectrochemicalperformancewithanapparentdensityofmorethan99.5%.ThisstudyhascertainreferencevaluefortheapplicationofLaNi5alloyinhydrogenstorageandhydrogenationpowerapplicationfields.

Keywords:

lowChighpurityLaNi5alloy;preparation;purification;compressionmolding;vacuumpyrolysisInrecentyears,hydrogenhasbeenregardedasanimportantcleanenergycarrierduetoitshighenergydensity,renewableandnon-pollutingcharacteristics.Thedevelopmentofefficientandstablehydrogenstoragematerialsisthekeytothepracticalapplicationofhydrogenenergy.LaNi5alloy,asarepresentativeintermetalliccompound,hasbeenwidelystudiedandappliedinhydrogenstorageandhydrogenationpowerfieldsbecauseofitsexcellenthydrogenstoragecapacity,goodhydrogenationanddehydrogenationkinetics.

Inordertoachievetherequirementsofhighpurity,lowcarbonandexcellentcrystallinityofLaNi5alloy,aseriesofpurificationandpreparationprocesseswerecarriedoutinthisstudy.Chemicalco-precipitationmethodwasusedtoprepareLaNi5alloyprecursor,andthencompressionmoldingandvacuumpyrolysiswerecarriedouttoformthefinalproduct.TheobtainedLaNi5alloyhasanapparentdensityofmorethan99.5%,indicatingthatthepreparationprocessiseffectiveinimprovingthecompactnessofthematerial.

TheX-raydiffraction(XRD)andscanningelectronmicroscopy(SEM)analysesrevealthattheLaNi5alloypreparedinthisstudyexhibitsgoodcrystallinityandmorphology.TheelectrochemicalperformanceoftheLaNi5alloywastestedbycharge-dischargeexperiments,indicatingthatthepreparedLaNi5alloyhasgoodhydrogenstoragecapacityandcyclingstability.TheresultsshowthatthepreparedLaNi5alloyhasexcellentelectrochemicalperformanceandcanpotentiallybeappliedinthefieldofhydrogenstorageandhydrogenationpower.

Insummary,thepreparationoflowChighpurityLaNi5alloybychemicalco-precipitation,compressionmoldingandvacuumpyrolysiswassuccessfullycarriedoutinthisstudy.TheobtainedLaNi5alloyhasexcellentcrystallinityandelectrochemicalperformance,indicatingitspotentialapplicationinhydrogenstorageandhydrogenationpowerfields.ThisstudyprovidesimportantreferencevalueforfurtherresearchandapplicationofLaNi5alloyFurtherstudiescanfocusonimprovingtheperformanceofLaNi5alloythroughdifferentpreparationmethodsandoptimizingitscomposition.Forinstance,onecanexploretheeffectofusingdifferentprecursorsandreactionconditionsonthepurityandstructureofthealloy.Additionally,theuseofpost-treatmenttechniquessuchasannealing,mechanicalmilling,andchemicaletchingcanbeinvestigatedtoenhancethecatalyticactivityandstabilityofthealloy.

Besides,theapplicationofLaNi5alloycanbeextendedbeyondhydrogenstorageandhydrogenationpower.Forinstance,itcanbeutilizedasacatalystforvariousreactionssuchashydrogenation,dehydrogenation,andoxidation.Thealloy'suniqueproperties,suchashighcatalyticactivity,excellentstability,andlowcost,makeitapromisingalternativetootherpreciousmetal-basedcatalysts.

Furthermore,futureresearchcanexploretheintegrationofLaNi5alloywithothermaterialstoenhanceitsperformanceinvariousapplications.Forexample,thecompositeofLaNi5andgrapheneorcarbonnanotubescanincreasethespecificsurfaceareaofthealloy,thusimprovingitscatalyticperformance.Inaddition,thehybridizationofthealloywithothermetalhydridescanimproveitshydrogenstoragecapacityandcyclingstability.

Inconclusion,thesynthesisandcharacterizationoflowChighpurityLaNi5alloyinthisstudydemonstratethepotentialofthealloyforhydrogenstorageandhydrogenationpowerapplications.Furtherresearchcanfocusonimprovingtheperformanceofthealloyandexploringitsapplicationsinotherfields.LaNi5alloy'suniquepropertiesmakeitapromisingcandidateforthedevelopmentofnewmaterialswithhighperformanceandlowcostOnepotentialareaforfurtherresearchisimprovingthealloy'shydrogenstoragecapacity.AlthoughLaNi5hasahigherhydrogenstoragecapacitythanmanyothermetalhydrides,itfallsshortoftheUSDepartmentofEnergy's(DOE)targetof6wt%foron-boardvehicularhydrogenstoragesystems.SomepossibleapproachesforincreasingthehydrogenstoragecapacityofLaNi5includealloyingwithotherelements,changingthesynthesismethod,andmodifyingthecrystalstructure.

AnotherareaofinterestisenhancingthecyclingstabilityofLaNi5.Formostapplications,itisimportantforthehydrogenstoragematerialtobeabletoundergomultiplecyclesofhydrogenationanddehydrogenationwithoutlosingitsstoragecapacityordegradinginperformance.LaNi5isknowntosufferfromdegradationoverrepeatedcycles,whichisonereasonwhyithasnotbeenwidelyadoptedforcommercialapplications.Onewaytoaddressthisissueistooptimizethehydrogenationanddehydrogenationconditionstoreducethestrainonthealloyduringcycling.Anotherapproachistouseadditivesorcoatingstoimprovethestabilityofthealloy.

Inadditiontohydrogenstorage,LaNi5haspotentialapplicationsinotherareas,suchaselectrocatalysis,sensors,andactuators.Forexample,LaNi5-basedelectrodeshavebeenshowntobeeffectiveforgeneratinghydrogenfromwater,whichcouldbeusefulforrenewableenergyproduction.LaNi5-basedsensorshavebeendevelopedformonitoringhydrogenconcentrationsinindustrialsettings,suchasfuelcellsandrefineries.LaNi5-basedalloyshavealsobeenstudiedfortheiruseinmagnetostrictiveactuators,whichconvertmagneticenergyintomechanicalmotion.

Overall,thesynthesisandcharacterizationofLaNi5alloyinthisstudyprovideafoundationforfutureresearchintothematerial'spropertiesandapplications.LaNi5isaversatileandpro