纳米稀土金属与合金的制备及其结构与性能的研究

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1、ABSTRACTABSTRACTBecauseofthesignificantlyincreasedsurfaceareaandgrainboundaryarea，thenanoscalerare．earthmetalsandalloysexhibitsomenewfeaturesintherespectsofandstructuralcrystalstructure，thermodynamics，phasetransformation，functionalwiththoseoftheconventionalrare—earthmaterials．Itisofproperties，aScomp

2、aredgreatimportancetounderstandthefundamentalpropertiesoftherare-earthmetalsandalloysonthenanoscaleforstudyinganddevelopingthenewnanoscalerare-earthmaterialswithhighperformance．Inthepresentpaper,thenanopowdersandnanocrystallinebulksofaseriesofrare-earthswereprepared，usingtheinert—gaScondensationmeth

3、odandsparkplasmasintering(SPS)technique，respectively．andmechanicalpropertiesofthenanoscaleFurther,thephysical，thermodynamicrare．earthsweremeasuredandanalyzed．ThenanocrystallineSmC03，Sm2Col7andSmC09．8alloybulkswithsingle-phasestructurewereprepared，usinganinnovatedrouteincludingthehomogenizationheattr

4、eatmentoftheas—castingot，highenergyballmillingtoobtaintheamorphousalloypowder,andconcurrentconsolidationandnanocrystallizationintheSPSprocess．Moreover,thecrystalstructure，phasestability,phasetransformationbehaviorandtheperformanceofthenanocrystallineSm—Cobulkswereinvestigatedrespectively．alloyTherar

5、e．earthnanoparticlespreparedbytheinert-gascondensation，suchasDy,E‘Nd，TbandGd，werefoundtohaveasingle-crystalhexagonalstructure；whileSmwerefoundtohavethetwocoexistingphaseswithhexagonalandnanoparticlesrhombohedralcrystalstructures．Thephysical，thermodynamicandmechanicalrare．earthnanocrystallinebulkswer

6、emeasuredandpropertiesofthepreparedanalyzed．Thereasonsthatthepropertiesofthenanoscalerare-earthmetalsdifferremarkablyfromthoseoftheconventionalcoarse-grainedpolycrystallinebulkswereexplainedbaSedonthephysicalbackgroundofthenanoscaleeffects．ThenanocrystallineSmC03alloybulkwithasingle-phasestructurewa

7、sprepared，andthecrystalstructureandmagneticpropertieswerestudied．ItWaSfoundthatthenanocrystallineSmC03alloyhasasingleBe3Nb—typerhombohedralstructure，ahighcoercivityof33kOeandahighratiooftheremanencewi