碳纳米管2f钡铁氧体复合材料的制备、表征与电磁参数-研究

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1、ABSTRACTelementcontentof22.6%canbegained,whichismuchmorehigherthanthecontentofoxygeninregularconcentratedacidoxidizedMWNTs(around6%).ThemicrographofhydrothermaloxidizedMWNTsareobservedusingSEM.ItisfoundthattheeffecttoMWNTsmechanicpropertiesissupposedtobeunderc

2、ontrol,forthetubestructureandthetubelengthismaintainedduringthehydrothermaloxidizingprocess.Secondly,thispaperhasdoneapreparativestudyofsynthesizingnanosizedBaFe12O19applyingahydrothermalprocess.NanosizedMtypeBaFe12O19hasbeensynthesizedat140℃,160℃and180℃,respe

3、ctively.TheobtainedbariumferritepowderischaracterizedusingXRDandTEM.ItisfoundthatthegrainsizeofBaFe12O19increasesasthesynthesistemperatureincreasesandthebariumferritesynthesizedat180℃hasamoreperfectcystalinitywithagrainsizeat60nm.Complexpermittivityandpermeabi

4、lityaremeasuredusingavectornetworkanalyzerinascanrangeof2-18GHz.Itisfoundthatthebariumferritesosynthesizedisagoodmagneticlosstypemicrowaveabsorberwitharelativelyhighimaginarypartofcomplexpermeability(μ”max=0.5)andcanbeusedtoimprovethemagneticpropertiesofMWNTsi

5、nthefollowingchapter.Lastly,thispaperhassuccessfullysynthesizedakindofMWNTs-BaFe12O19compositebybringinghydrothermaloxidizedMWNTsinthehydrothermalsynthesisreactionofBaFe12O19.ThecompositepowderischaracterizedbyXRDandTEM.ItisfoundthattheMWNTsarewellcoatedbyBaFe

6、12O19.Thecomplexpermittivityandpermeabilityofthecompositeismeasuredusingavectornetworkanalyzerinascanrangeof2-18GHz.ItisfoundthattheimpedancematchofMWNTshasbeengreatlyimprovedaftercoatedwithBaFe12O19.ComparedwithhydrothermaloxidizedMWNTs(ε’max=170,ε“max=130,μ‘

7、max=0.85,μ”max=0.25),thecoatingofBaFe12O19haseffectivelyloweredthedielectricpropertiesofMWNTs(ε’max=60-100,ε“max=45-55)andincreaseditsimaginarypartofcomplexpermeability(μ”max=0.4)inthesametime.ThedecreaseofrelativecontentofMWNTsinthecompositeisconducivetolower

8、thevalueofcomposite’complexpermittivityand第IV页ABSTRACTincreasethevalueoftheimaginarypartofitscomplexpermeability.Keywords:Hydrothermalprocess,carbonnanotubes,modificationofcarbonna