BaO-Sm-,2-O-,3--TiO-,2--Ta-,2-O-,5-電介質陶瓷新體系及其改性.pdf

1、浙江大學碩士學位論文BaOSmOTiOTaO電介質陶瓷新體系及其改性姓名：李涓申請學位級別：碩士專業(yè)：材料學指導教師：陳湘明2001.1.1——————————A——t—he—s—i—s—s—u—b—m—it—t—ed——to——Z—h—e—ii—a—n—g—U——n—iv—e—rs—i—ty——fo—r—th——e—m——a—st—e—r—d—e—g—reeJuanLi——AbstractInordertosearchnewcandi

2、datesforhigh一￡microwavedielectricceramics，theBaO_Sm：01一TiO二Ta：0、quatemaDsystemwereinvestigatedwithrespecttotheeffectsofsinteringconditionsandcompositionsuponthemicrostructuresandthedielectricpropertiesBa、Sm2^Ti4T瓦OⅫnon—s

3、toichiometriccompositionswerealsoinvestigatedtogetherwithco—substitutionintheAsitesandBsitesofBa4Sm，TijT亂OⅫInthispapersomepromisingcandidatesforhigh一￡nlicrowavedielectricceramicswereproposedinanew“tungsten—bronzesxstemof

4、BaO—Sm20一TiO二一TaOsInthisquaternarysystemBa5SmTiTa7030，Ba_lSm2Ti4TarO，oandBasNd3Ti5Ta5030tendedtoformthetungsten。bronzephaseandtheceramicsbasedonthesecompositionshaveahighdielectricconstant(e2134～175)andalowdielectricloss

5、intheorderof10～butalargertemperaturecoefficientofdielectricconstant(x，=一2500ppm／℃～t500ppm／℃)MeanwhileBazSm4Ti6Ta40ⅫandBaSmsTirTa30；c，generallyhadamorecomplexphaseconstitution，andarelativelysmalltemperaturecoefficient01’d

6、ielectricconstantinthetemperaturerangeof20to95“CcombinedwithlowerdielectricconstantcanbeachievedintheceramicsbasedonthesetwocompositionsBasedonthecompositionsensitivityoftheBaO—Sm：O：一TiO二Ta，otsjstemcompositioncontrolling

7、wasintroducedintoBajSm二Ti4Ta60∞toimproveitstemperatnrecoefficientandBa4iSm22xTi。僻嘞nonstoichiometriccompositionswereimestigatedHithincreasingxthetemperaturecoefficientofdielectricconstantofBa4^Sm22＼Ti4Ta60Ⅻceramicswassign

8、ificantl)reducedHhilethedielectriclossI口alsosuppressedbutthedielectricconslautdecleasedobviouslyInordertoimprovethetemperaturecoefficientnithoutobviousdecreaseindielectricconstantco—substitutionofSrandTiintheAsitesandBsi

9、tesofBa4Sm：Ti4TkOⅦ、、asproposedComparedwithBa4Sm!Ti4TkOⅦceramicsthedielectriclossof(Ba、Sr：)Sm!TihT‰、o訓、、ceramicsx～assignificantlyreducedAtthefrequencyof500KHzand5MHzthedielectricloss、~aevenlessthan104Thetemperaturecoeffic

10、ientofthedielectricconstantcouldalsobesuppressedpronouncedlHbilethedielectricconstantwasabove110Thegooddielectricproperties117elcobtainedforj23：￡。110，tan6200009(atIMHz)，t，=一470ppm／℃illldfor3=2j￡=I13，tan6=00011(1MHzlTt=64

11、0ppm(IngeneralBaOSm20=TiO：一]a二0tsystemhadgreatapplicationpotentialinthefieldolhigh一￡microwavedielectricceramic‘a(chǎn)ndtunablemicrowavedielectricceramicsInthispaperthcgoodhigh一￡dielectricceramics、、hichcouldbeusedinhigh—ffeque

12、nccapacitorsandternperalure‘compensatecapacitors、、ereobtainedinthemodifiedBa4Sm、Ti41k0≈ceramics|1me0fvaltlecouldbefonherimproxednewcandidatesforhigh一￡microx、a、edielecniceelamic、arcexpectedintheBaO—Sm：0：一TiO一Ta：0；quaterna