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NaZn_(13)型LaFe基室温磁致冷材料研究进展(英文) ResearchProgressofNaZn_(13)LaFe-BasedRoomTemperatureMagnetocaloricMaterials Introduction Magnetocaloriceffect(MCE)referstothephenomenonthatcertainmaterialsexperienceachangeintemperaturewhenexposedtoamagneticfield,duetothemagneticcouplingbetweenthematerial'smagneticmomentsanditslatticestructure.Thiseffecthaspotentialapplicationsinrefrigerationandcoolingsystems,whichcouldofferamoreenergy-efficientalternativetoconventionalcoolingtechnologies.Inrecentyears,thedevelopmentofroomtemperaturemagnetocaloricmaterialshasbeenamajorfocusofresearch.OnesuchmaterialisLaFe-basedNaZn_(13),whichhasshownpromisingresultsintermsofitsMCEproperties. PropertiesofNaZn_(13)LaFe-basedMaterials LaFe-basedNaZn_(13)alloysexhibitagiantMCEthatiscomparabletoorevengreaterthanthatofconventionalferromagneticmaterialssuchasgadolinium,whichiscommonlyusedincommercialmagneticrefrigerationsystems.NaZn_(13)LaFealloyspossessalargeadiabatictemperaturechange(ΔT_ad)ofupto3-4Katroomtemperature,accompaniedbyasignificantmagnetocaloriceffectentropychange(ΔS_M)of20-25J/kgK.Moreover,thesematerialstypicallyhaverelativelylowcost,highstability,andareenvironmentallyfriendly. PreparationMethodsandStructuralCharacteristicsofNaZn_(13)LaFe-basedMaterials TwoprimarymethodsforthepreparationofNaZn_(13)LaFe-basedmaterialshavebeenreportedintheliterature:meltingandhigh-energyballmilling.Themeltingmethodinvolvesmeltingtheconstituentelementsinavacuumfurnaceandthensolidifyingtheresultantalloybywater-coolingorcopper-moldcasting.Theballmillingmethod,ontheotherhand,involveshigh-energyballmillingoftheconstituentelementsinanargonatmosphere,followedbyhotpressingorsparkplasmasintering.ThestructuralcharacteristicsofNaZn_(13)LaFe-basedmaterialsdependonthepreparationmethodused.Themeltingmethodgenerallyyieldsasingle-phasestructure,whereastheballmillingmethodtendstoproduceamulti-phasestructureconsistingoftheLaFe_13andNaZn_(13)phases.Themulti-phasestructureexhibitslowerthermalhysteresis,whichisanimportantfactorinthepr