鐵基磁性顆粒的制備及微波吸收特性研究.pdf

1、蘭州大學碩士學位論文鐵基磁性顆粒的制備及微波吸收特性研究姓名：郝志申請學位級別：碩士專業(yè)：材料學指導教師：王建波20090601摘要AbstractInrecentyears，considerableexperimentalinvestigationshavebeenfocusedontheeffectivemicrowaveabsorptionmaterialsinordertosolvetheexpendedelectromagne

2、ticinterferenceproblemsThreemicrowaveabsorptionmechanismswerefoundinthematerials：dielectricloss，conductionlossandmagneticlossMagneticlossmaterialshavebeeninvestigatedbroadlyfortheirhighcomplexpermeabilityMagneticmetalsan

3、dalloysareidealelectromagneticwaveabsorbermaterialsbecauseofhighercomplexpermeabilityathighfrequencyMetalFehashighersaturationmagnetizationandlowercoerciveforce，andironalloysalsoattractmuchattentioninthefieldofmicrowavea

4、bsorptionmaterialsManyresearchworkhavebeendoneonFeCo，F(xiàn)eNiandFe—SialloyetcHoweveronlyfewreportsaboutmicrowaveabsorptionpropertiesofFeZralloywerereporteduntilnowWepreparedFe—Zralloybymechanicalalloyingmethodandstudiedthemi

5、crowaveabsorptionpropertiesMeanwhile，inordertofindlowdensitymicrowaveabsorbmaterials，wealsoexploredthefabricationmethodtoobtainferrite／carbonnanotubescompositesusingimprovedcoprecipitationmethodThemainresultsare：FegoZrto

6、alloypreparedbyMAhashi【ghsaturationmagnetizationandlowcoerciveforceItexhibitsirregularsphericalparticleafterdrymilling，andhasgoodmicrowaveabsorptionpropertiesThemicrowaveabsorptionofFe90Zrl0alloy／paraffincompositeislesst

7、han20dB(morethan99％energywereabsorbed)atfrequencyrangefrom45to176GHzbychangingballmillparametersandthicknessIfNaClwasusedasprocesscontrolagent，F(xiàn)e90Zrloalloyshowsflakemorphologyandbettermicrowaveabsorptionpropertiescanbeo

8、btainedItispossibletogetabsorptionintensitylessthan20dBatfrequencyrangefrom28to159GHzbychangingball—millparametersandthicknessThemicrowaveabsorptionmechanismof‘thecompositeisferromagneticlossMultiwalledcarbonnanotubeshav