压电陶瓷性能参数

1TechnicalPublicationTP-226PropertiesofPiezoelectricityCeramicsVisittheMorganElectroCeramicsWebSite(s11/s33,s12/s13,s44/s66,ε11/ε33)varydrasticallywiththoroughnessofpoling.Thesetspresentedhereareself-consistentandholdforthelevelofpolingsuggestedbythecouplingfactorslisted.Thefourthsectiongivesdatarelatingtotemperatureandtimestability.Datafortheformerareforsamplessubjectedtoanappropriatetemperaturestabilizingtreatment.*Thistreatmentreducesmarkedlytempera-turehysteresiseffectsandcausesarelativelysmalldecreaseinpiezoelectriccouplingandincreaseindielectricconstant.Temperaturehysteresisabouttheorthorhombic-tetragonaltransitionofCeramicBis)however,noteliminatedbyanyknownstabilizingtreatment.DatashownforCeramicBareforincreas-ingtemperatureonly,andchangesatthetransitionaremoreextremewithdecreasingtemperature.Agingdataarelistedaschangepertimedecade.Thesechangestendtobelinearasfunctionofthelogoftine,buttherearesignificantdeviationsfromthisbehav-iour.TheagingratesareusuallyalittlehigherthanlistedwhentheelementhaspiezoelectricpropertiesstrongerthanthoselistedinSectionIII,andtheyaresomewhatlowerifpiezoelectricpropertiesareweaker.SectionVlistshighsignalproperties,includingdataforbothmechanicalandelectricdrivingconditions.Thesedataallowcomparisonoftheseveralcomposi-tionswith.respectto.useinacousticradiatingtrans-ducersorinhighvoltageelectricalgeneratingsys-tems.Foracousticradiatingtransducersimportantcriteriaarevaluesoftan∂withelectricdrive,changeofpermittivityandsensitivitywithmechanicalbias,allowablemechanicalbias,dynamicstrength,anddependenceofmechanicalQondynamicstress.Forelectricalgeneratingsystemsthelimitingfactoristhemaximumcompressivestress(cycled)whichmaybemaintainedwithoutsignificantdegradation.Withacousticreceivers,eventhoughthesearenothighsignaldevices,severalpropertieslistedinSectionVaresignificant,sincehydrophonesareoftenoper-atedatgreatdepthintheoceanandthereisthereforeasignificantmechanicalbiasstress.Cyclingeffectsmaybeimportantifthehydrophoneistobesub-mergedrepeatedly.SectionVIlistsdatarelatedtothermaleffects,includ-ingpyroelectricconstants,thermalexpansion,thermalconductivity)andheatcapacity.Thepronouncedeffectsoftemperaturestabilizationonthermalexpan-sionandpyroelectricconstantsareshownThegraphsamtheendofthisreportshowvariationofεT33,kp,s31d31,N1,andQmwithtemperatureforthevariousceramics.ThecurvesforPZT-5AandPZT-4holdonlyaftertemperaturestabilization.*Thistreatmentisnotordinarilyappliedtoproductionspecimens,andisactuallyrecommendedonlyforPZT-4andPZT-5A.Withtheformeritconsistsofaone-hoursoakat200°C.ThestabilizingtreatmentforPZT-5Aconsistsofa15-secondsoakat250°Cinoilfollowedbya60-secondsoakinroomtemperatureoil,withtheprocessrepeatedatleastfivetimes.TherespectivechangesinkandεT33/ε:areapproxi-mately-10%and+10%forPZT-4and-9%and5%forPZT-5A.ChangesinN1aregenerallylessthan1%.Stabilizationtolowerpeaktemperaturecanbeaccomplishedbyreducingthetemperatureofthesoak.Thiswillalsoreducethechangesinparameters.WithlargePZT-5Aspecimensthesoaktimesmustbeincreasedsothattheentirespecimenreachesthesoaktemperature.2GENERALCOMPARISONCeramicBisamodifiedbariumtitanatewhichoffersimprovedtemperaturestabilityandloweragingincomparisonwithunmodifiedbariumtitanate.PZT-2maybeusedforrequirementsoflowdielectricconstantbutitisotherwiseinferiorinnearlyallrespectstoPZT-4orPZT-5A.PZT-4isrecommendedforhighpoweracousticradiatingtransducersbecauseofItshighresistancetodepolarizationandlowdielectrIclossesunderhighelectricdrive.Itshighresistancetodepolarizationundermechanicalstressmakesitsuitableforuseindeep-submersionacoustictransducersandastheactiveelementinelectricalpowergeneratingsystems.PZT-5Aisrecommendedforhydrophonesorinstru-mentapplicationsbecauseofitshighresistivityatelevatedtemperatures,highsensitivity,andhightimestability.CeramicBPZT-2PZT-4PZT-5APZT-5HPZT-8%ofHighestRatedCeramicCouplingfactor517289921008Shortcircuitsensitivity(d)2626506410038Opencircuitsensitivity(g)3710068655069Permittivity3513385010029Compliance52717510010070Relativecoerciveelectricfield4446100128-Relativestrainatrelative23241001516-coerciveelectricfieldRelativecoercivemechanical25-10025