固相含量对氧化钇稳定氧化锆性能的影响
Influncesofsolidloadinonproperites
ofyttria—stabilizedzirconia。
LIuXiao-guang,LIGu叫un,ToNGJian-feng,cHENDa-ming(NationalKeyLaboratoryofAdvancedcompositeS,BeijinglnstituteofAeronautical
Macerials?Beijing100095?china)Abstract:TheinfluencesofsolidsloadingontherheoIogicalpropertiesusedforaqueousgel—casting
werestudied,andalsointhispaperthemicrostructures,densities,
andstrengthsofyttria—stabi“zedzirconiawereinVestigated?Resultsshowthataqueousslurriesofdifferentsolidloadingsexhibitshearingthinningbehavior.Densitiesofgreenbody
increasewithincreasirlgsolids,andstrengthsdecrease.However,densitiesofsinteredbody
increasefirstlyandreachmaximumat53Vol%,thendecrease?Strengthsdecreasewithincreasingsolidloadings.
Microstructuresof53volsolidloadingaremoreuni{ormandlesspores?So53vol%iscompromisingsolidloadinginthissystem.
KeywoI?ds:solidsloading;rheologic萌properties;aqueousgel—casting;yttria。stabilized
zirconja;aqueousslurrles;poresCLCnumber:TQl74.758
1Introduction
DocumentcOde:AArticleID:l001—973l(2005)05一0767一04
Yttria—stabilizedzirconia(YSZ)isthemostwidelyusedelectrolytematerialforoxygensensorands01idox—idefueIcellsapplication.PurezirconiacannotactasagoodelectrolyteduetoitspoorionicconduchVityandphasetransformation(monoclinicandtetragonal)onheatingassociated
withalargeVolumechange.DopingofZrOzwith8m01%yttriacanstabiIizethecubicfluoritephaseand,intheprocess,increaseitsoxygenVacancy
concentration1eadingtoanenhancedionicconductivity.Thismakesstabilizedzirconiasuitableforuse
asane一
1ectrolytematerialandyttriaisthemostcommonlyuseddopantforstabilizingzirconiaforthe
aforesaidapplica—tion[1I.
Denseandfine—grainedceramicsarerequiredformanyapplications.Thecontrolofgreencompactmicro—structuresaswellastheselectionofpowderisimportant.Specifically,densegreencompactswithuniformlydistributedsmallDoressintertodenseceramics.1tisdifficulttomakedesirablecompactsbyconVentionalfabri—cationmethods[引.Thetraditionalfabricationofceramicpartsislimitedtoseveralformingproceduressuchaspressing,slipcasting,andinjectionmolding.Althougheachtechniquepossessesmerits,noneonitsownisca—pableofmeetingtoday’schallengessuchasreproducibility,reliability,andfabricability[3~5].Aqueousgelcast—ingisanearnet—shapeformingtechniqueandisbasedonideasborrowedfromtraditionalceramicprocessingandfrompolymerchemistry.ItisagenericprocesseswhichcanbecarriedoutreadilyinavailabIeequipment.Inad—dition,aqueousgelcastingisalowcostceramicfabricationtechniquethatcan
beemployedtoproduce1argeareaandthin—substrateYSZelectrolyte[¨.Thedispersionofpowdersisanimportantprocessforthepreparationofdesirablecompacts.Solidloadinghasanimportanteffectondispersionofpowdersandflowingofaqueousslur—ries.Thepresentworkaimstostudythecorrelationbetweenslurryrheology,densities,strengths,microstruc—turesandsolidloadingsofYSZaqueousslurries.
2Experimentalprocedures
Theyttria—stabilizedzirconiapowders(YSZ,99.9%purity)haveanaveragesizeof1.5肛m.Acrylamide(AM)wasusedasthemonomerandN,N—methylenebisacrylamide((C2H3CONH)2CH2,MBAM)actedasthecross—linker.N,N,N’,N’一tetramethylethylenediamine(TEMED)and(NH4)2S208wereusedascatalystandinitiatorrespectively.AcommercialproductDAproducedbyBeijinginstituteandchemicalindustrywasselect—edasthedispersants.YSZslurrieswithdifferentsolid10adingswereball—milledfor20htogiveweUdisperseda—aueous
slurries.Thentheslurriesweredeairedfor15min.Afteraddingcatalystsandinitiator,theseslurrieswerecastineitherplasticorglassm01ds.Aftergelation,theceramicpartsweredem01dedandimmediatelydriedatroomtemperature.Thenbothbinderburnoutandsinteringwerecarriedoutinairfurnace.Rheological
*Receiveddate:2004—11一03Corr髑pondingauthor:LIUXia0-guang
Bi0鬓阳phy:LIUxia0-guang,male,doctor,engineer,majorinceramicandceramicmatrixcomposites.
万方数据
万方数据