复相陶瓷结构和性能论文

《复相陶瓷结构和性能论文》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、浙江大学博士学位论文AbstractTherelationshipsbetweenpropertiesandstructuresforpiezoelectricsecondaryphasetoughenedmultiphaseceramicsandcompositedielectricceramicshavebeeninvestigatedinthisdissertation．Sr2Nb207／3y-TZP,Sr2Nb20T／ZTA，BaTi03／8Y-FSZ，Nd2Ti207／8Y-FSZ．CaTi03／LaSrAl04andSr2Nb20T／LaAl03multiphasecerami

2、cshavebeenpreparedandthemechanicaland／ordielectricpropertieshavebeenanalyzedtogetherwimthemicrostructures．Thefollowingprimaryconclusionshavebeendrawn．IntheSr2N_b207／3Y-TZP(3m01％yttria-dopedte拄agonalzireoniapolycrystal)system，thepiezoelectricsecondaryphasecouldCO·existwith3Y-TZPmatrix，andthetransfo

3、rmabletetragonalphasein3Y-TZPceramicsisaffectedbythecontentofsecondaryphaseandthesinteringcondition．ThefracturetoughnessisenhancedsignificantlywithincorporatingSr2Nb207into3Y-TZPceramics，andthehighestfracturetoughness．13．7MPa·m1“isachievedinO，005Sr2Nb207／0．995(3Y-TZP)ceramicssinteredat15000Cfor6h，

4、whichistwicethatofthematrix．Moreover,itshouldbeemphasizedthatahighKscvalueof10．OMPa‘m“2isachievedinthepresentcompositeceramicsevenwherethetransformationtougherringmechanismiSinactiveandthepiezoelectricsecondaryphasetougheningplaystheprimaryroleinthiscomposite．IntheSr2Nb207／ZTA(zirconiatoughenedalu

5、mina，45Z102’55A1203)system，thepiezoelectricsecondaryphasewillreactwithaluminainceranficmatrixtoformplateletSrAll2019phase．Combiningtheeffectsofgrainbridging，transformationtougheningandmicrocrackingtoughening，thehighestfracturetoughness，10．0MPa·m“2isachievedinO．005Sr2Nb207／0．995ZTAceramicssintereda

6、t16000Cfor6hours．IntheBaTi03／8Y-FSZ(8m01％yttfia-dopedfullystabilizedzirconia)system，theintroductionofsecondaryphasecouldsignificantlydecreasethesinteringtemperatureof8Y-FSZceramics．ThesecondaryphaseisrhombohedralBa(Til-xZrx)03ferroelectriephaseforthecompositewith5m01％additive，whileforthosewithhigh

7、eradditivecontent，thesecondaryphaseschangetocubicBa(Tit—xzrx)03phase．nehighestfracturetoughnessreaches6．08MPa·m172for0．05BaTiOfl0．95(SY-FSZ)sinteredat14750Cfor3h，wherethepiezoelectricsecondaryphasetougheningplays