稀土永磁材料ndfeb磁粉改性的研究

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1、浙江工业大学硕士学位论文稀土永磁材料NdFeB磁粉改性的研究摘要本课题采用磁场搅动直流电沉积装置在NdFeB磁粉表面电沉积纳米级金属镀层。选用的金属元素是铁、铜、锌、镍及其组合镀层。改善了Ndl；eB磁粉耐腐蚀性能和磁性能。分析测试了包覆金属镀层的NdFeB磁粉的电极电位值、包覆镀层前后NdFeB磁粉制备的粘结磁体的电阻率与磁性能。检验NdFeB磁体的耐腐蚀性能和磁性能。磁粉电极电位表现为NdFeB磁粉和包覆金属镀层的混合电位。探讨了电极电位在金属腐蚀性能方面的作用。金属锌镀层比基体NdFeB电极电位更负，在发生电化学腐蚀作用时，可起到牺牲阳极保护基体的作

2、用。而金属镍镀层是最常应用的NdFeB磁体的防护镀层。粘接NdFeB磁体的电阻率表现为NdFeB磁粉和包覆金属层的混合电阻率。结果表明：包覆zn／Ni双金属层的NdFeB磁体的电阻率却异常增大；包覆金属cu镀层的电阻率值最小，因为金属cu的电阻率较小，是良好的导电材料。能够改善NdFeB磁体的导电性能的目的。浙江工业大学硕士学位论文包覆前后的粘接NdFeg磁体的矫顽力有不I司程度地降低：而最大磁能积和剩余磁感应强度却变化不大。关键词：NdFeB磁粉，电沉积，改性，耐腐蚀Ⅱ浙江』=、Ip大学硕士学位论文STUDYoNMoDIFIEDNDFEBPERMANEN

3、TMAGNETICPOWDERABSTRACTThisthesisdescribeselectrodepositednano—layeronNdFeBmagneticpowdersbythebarrelplatingDCelectroplatingmethod．Fe，Cu，Ni，Zn，Fe／NiandZn／Ninano—layerwerefabricated．ResearchresultsindicatedthatthecorrosionresistanceandpracticablepropertiesofNeodymium—iron-boronmagn

4、eticpowderswereimprovedTheelectrodepotential，resistivelyratioandmagnetismoftheboundedNdFeBpermanentmagnetsthatweremodifiedweretestedintheresearch．TheelectrodepotentialoftheNdFeBmagneticpowdersandtheplatingwasmeasured．thecorrelationbetweentheelectrodepotentialandcorrosionresistance

5、ofNdFeBmagneticpowderswasdiscussed．TheelectrodepotentialofzincwaslessthanthatofNdFeBmagneticpowdersNdFeBmagneticpowderswereprotectedbecauseZinchadbeentheanodethroughtheelectrochemistrycorrosion．NikelplatingonNdFeBpermanentmagnetswasgenerallyadoptedⅢ浙江工业大学硕士学位论文Themixedresistivelyr

6、atiooftheboundedNdFeBmagnetsandtheplatingwasanalyzed．TheresultsindicatedthattheresistivelyratiooftheNdFeBmagneticpowderscladdedbytheZn／Niwashiglllylargerthanthatofnon-claddingNdFeBmagneticpowders．Onthecontrary，theresistivelyratiooftheNdFeBpermanentmagneticpowderscladdedbycopperwas

7、lowest．Becausethecopperresistivelyratioislow,itisagoodconductor．Electrodepositednano—layerplatingonthesurfaceofNdFeBmagneticpowdersmaybeabletoimproveonelectricitycapabilityoftheboundedNdFeBmagnets．AccordingtostudyonmagneticparametersoftheboundedNdFeBmagnets：coerciveforce(Hc)，resid

8、ualmagnetismintensity(Br)，(BH)max