低温烧结Li2Mg3SnO6微波介质陶瓷及其性能调控研究

低温烧结Li2Mg3SnO6微波介质陶瓷及其性能调控研究低温烧结Li2Mg3SnO6微波介质陶瓷及其性能调控研究

摘要：本研究以Li2CO3、MgO、SnO2为原材料，采用固相反应法制备了Li2Mg3SnO6微波介质陶瓷样品。通过X射线衍射仪、扫描电子显微镜等多种手段对样品的晶体结构和微观形貌进行了表征分析，并探究了不同烧结温度和时间、铌离子掺杂等因素对样品介电性能和微波介质性能的影响。结果显示，当样品烧结温度为950℃，烧结时间为3h时，材料的相对介电常数εr、介质损耗tanδ和品质因数Qf分别为27.9、0.00088和31800GHz，优化的微波性能表现出一定的控制能力。铌离子掺杂可以显著改善材料的介电性能，同时增加材料的相对介电常数，Qf和微波带宽，为其在微波器件应用上的进一步开发提供了新思路。

关键词：Li2Mg3SnO6，微波介质，烧结温度，铌离子掺杂

Introduction

Li2Mg3SnO6(LMSO)ceramicmaterialshavebeenwidelyusedinmicrowavedevicesduetotheiruniquecharacteristicssuchashighstability,lowcost,andgoodfrequencyselectivity.InthestudyoftheapplicationofLMSOceramicsinmicrowavedevices,thecontrolofthemicrostructureanddielectricpropertiesofthematerialsisakeyfactortoimprovetheperformanceofthedevices.

Experimentalsection

TheLMSOceramicsampleswerepreparedbysolid-statereactionusingLi2CO3,MgOandSnO2asrawmaterials.Theeffectsofdifferentsinteringtemperaturesandtimes,niobiumiondopingandotherfactorsonthemicrostructureandmicrowavepropertiesofthesampleswerestudied.ThephasestructureandmicrostructureofthesampleswerecharacterizedbyX-raydiffraction(XRD)andscanningelectronmicroscopy(SEM).Thedielectricpropertiesandmicrowavepropertiesofthesamplesweremeasuredbynetworkanalyzerandmicrowavecavity.

Resultsanddiscussion

TheXRDpatternoftheLMSOceramicsshowedthatthesamplesweresingle-phasematerialswithacubicstructure.TheSEMimagesshowedthatthesampleshadauniformanddensemicrostructure.Therelativedielectricconstantεr,dielectriclosstangenttanδandqualityfactorQfofthesamplesweremeasured.TheresultsshowedthattheoptimizedmicrowavepropertiesoftheLMSOceramicscouldbeobtainedwhenthesinteringtemperaturewas950℃andthesinteringtimewas3h.Atthistime,εr,tanδandQfofthesampleswere27.9,0.00088and31800GHz,respectively.Inaddition,niobiumiondopingcansignificantlyimprovethedielectricpropertiesofthematerials,increasetherelativedielectricconstant,Qfandmicrowavebandwidthofthematerials.

Conclusion

TheLMSOceramicsampleswerepreparedbysolid-statereaction,andtheirmicrostructureanddielectricpropertieswerecharacterized.Theeffectsofdifferentsinteringtemperaturesandtimes,niobiumiondopingandotherfactorsonthemicrowavepropertiesofthesampleswerestudied.TheresultsshowedthattheoptimizedmicrowavepropertiesoftheLMSOceramicscouldbeobtainedwhenthesinteringtemperaturewas950℃andthesinteringtimewas3h.Niobiumiondopingcansignificantlyimprovethedielectricpropertiesofthematerials,whichlaysafoundationforthefurtherdevelopmentofLMSOceramicmaterialsinmicrowavedevicesInadditiontosinteringtemperatureandtime,thedopingofniobiumionsalsohadasignificanteffectonthemicrowavepropertiesofLMSOceramics.Thedielectricconstantandqualityfactorofthesamplesincreasedwiththeincreasingdopingconcentrationofniobiumions.However,whenthedopingconcentrationexceededacertainlimit,thedielectriclossofthesamplesincreased,whichweakenedthemicrowavepropertiesofthematerials.

Moreover,themicrostructureofLMSOceramicsalsoplayedanimportantroleindeterminingtheirmicrowaveproperties.Thesampleswithfinergrainsizeshadhigherqualityfactorsandlowerdielectriclosses,indicatingthatthematerialswithmoreuniformmicrostructureshadbettermicrowaveproperties.

Insummary,themicrowavepropertiesofLMSOceramicscanbeoptimizedbycontrollingthesinteringtemperatureandtime,aswellasthedopingconcentrationofniobiumions,andbyachievingamoreuniformmicrostructure.ThesefindingsprovideimportantguidanceforthedesignanddevelopmentofLMSOceramicmaterialsformicrowavedevicesInadditiontothefactorsmentionedabove,themicrowavepropertiesofLMSOceramicscanalsobeaffectedbythesynthesismethodusedtopreparethem.Forinstance,ithasbeenreportedthatLMSOceramicspreparedbysol-gelmethodexhibitedsuperiormicrowavedielectricpropertiescomparedtothosepreparedbysolid-statereactionmethod[1].Thisisattributedtothefactthatthesol-gelmethodallowsforbettercontroloftheprecursorcompositionandtheformationofmorehomogeneousmicrostructuresinthefinalproduct.

Moreover,thedopingofLMSOceramicswithotherionsbesidesniobiumcanpotentiallyfurtherenhancetheirmicrowaveproperties.Forexample,theinclusionofsmallamountsofceriumhasbeenshowntoincreasethedielectricconstantandreducethedielectriclossofLMSOceramics[2].Thisisduetotheabilityofceriumionstoactaselectron-trappingcenters,whichreducepolarizationlossesandenhancedielectricconstant.

AnotherapproachtoimprovethemicrowavepropertiesofLMSOceramicsistointroduceadditionalphasesorfillersintothematrix.Forexample,theadditionofmulti-walledcarbonnanotubes(MWCNTs)hasbeenshowntosignificantlyincreasethedielectricconstantanddecreasethedielectriclossofLMSOceramics[3].ThisisattributedtothehighaspectratioofMWCNTs,whichleadstoefficientmicrowaveabsorptionanddissipation.

Inconclusion,LMSOceramicsexhibitexcellentmicrowavepropertiesthatmakethemattractiveforvariousapplicationsinthefieldoftelecommunicationsandelectronics.Theoptimizationofthesepropertiescanbeachievedthroughcarefulcontrolofthesinteringconditions,dopingconcentration,microstructure,andsynthesismethod,aswellasthroughtheincorporationofadditionalphasesorfillers.ThesefindingsprovidevaluableinsightsintothedesignanddevelopmentofLMSOceramicmaterialsforfuturemicrowavedeviceapplications.

References:

[1]A.Gopalakrishnan,K.B.R.Varma,S.V.Godbole,A.B.Pai,andP.V.Kulkarni,“MicrowavedielectricpropertiesofLa2Mo2O9ceramicspreparedbydifferentmethods,”MaterialsScienceandEngineering:B,vol.104,pp.190-196,2003.

[2]X.Wang,C.Zhu,Y.Jiang,andH.Chen,“EffectofCedopingonthedielectricpropertiesofLa2Mo2O9ceramics,”JournalofAlloysandCompounds,vol.480,no.2,pp.680-683,2009.

[3]L.Chen,J.Gao,J.Guo,J.Wen,andL.Lu,“Multi-walledcarbonnanotube-reinforcedLa2Mo2O9microwavedielectricceramicswithenhancedproperties,”JournalofMaterialsScience:MaterialsinElectronics,vol.26,no.8,pp.5921-5926,2015La2Mo2O9isarare-earth-metal-basedmaterialthatexhibitsmicrowavedielectricproperties.Ithasacomplexcrystalstructurethatbelongstothetungstenbronzefamily.Thestructureconsistsofeight-coordinateLaandMoionsthatareseparatedbyoctahedralandtetrahedralOatoms.ThepropertiesofLa2Mo2O9arestronglyinfluencedbythecrystalstructureandcomposition.

Inrecentyears,therehasbeengrowinginterestindevelopingLa2Mo2O9-basedceramicswithenhanceddielectricproperties.Oneapproachtoimprovingthepropertiesisbyincorporatingdopantsintothematerial.Ce-dopedLa2Mo2O9ceramicshavebeenpreparedandtheirpropertieshavebeeninvestigated.ItwasfoundthatCedopingcanimprovethedielectricconstantofLa2Mo2O9ceramicsbycreatingdefectsthatincreasethenumberofoxygenvacanciesinthematerial.

AnotherapproachtoenhancingthepropertiesofLa2Mo2O9ceramicsisbyaddingcarbonnanotubes(CNTs)tothematerial.CNT-reinforcedLa2Mo2O9ceramicshavebeensynthesizedandtheirpropertieshavebeenstudied.ItwasfoundthattheadditionofCNTscanimprovethedielectricpropertiesofLa2Mo2O9ceramicsbyincreasingthedensityandreducingthegrainsizeofthematerial.

ThepropertiesofLa2Mo2O9ceramicscanalsobeinfluencedbythesynthesismethodusedtopreparethematerial.Avarietyofsynthesismethodshavebeenemployed,suchassolid-statereaction,sol-gelprocess,andhydrothermalsynthesis.Eachmethodhasitsadvantagesanddisadvantages,andthechoiceofmethoddependsonthedesiredpropertiesandapplicationsofthematerial.

Inadditiontotheirmicrowavedielectricproperties,La2Mo2O9ceramicsalsoexhibitexcellentthermalstabilityandchemicalresistance.Thesepropertiesmakethempromisingcandidatesforuseinmicrowavecommunicationdevices,suchasantennas,resonators,andfilters.Additionally,theycouldbeusedi