梯度功能材料研究进展课件

InteractiveexperimentationandthermodynamicmodelingWeipingGonga,MarcelleGaune-Escardb,ZhanpengJinaaStateKeyLabofPowderMetallurgy,CentralSouthUniversity,Changsha,Hunan,P.R.ChinabEcolepolytechnique,MecaniqueEnergetique,TechnopoledeChateau-Gombert,Marseille,France.TheCODATAconference,Beijing,China,2006InteractiveexperimentationanOutline1.Introduction2.StructuralbehaviorandthermodynamicpropertiesofSrZrO3

3.ThermodynamicmodelingandexperimentationofKBr-TbBr3system4.SummariesOutline1.IntroductionIntroductionPhasediagram’sfunctions:blueprintsorroadmapformaterialsdesign,development,processingandbasicunderstandingvisualrepresentationsofthestateofamaterial:T,P,CThecorrelationbetweenthermodynamicsandphaseequilibriumJ.W.GibbsModerndevelopment:modelingandcomputertechnologyphaseequilibriumcomputercalculationpossibilityCrucialthermodynamicmodelinginbinarysystemcanbeextrapolatedtomulti-componentsystemsQuestion:Canwebelievetheresultsofmodeling?IntroductionPhasediagram’sfuTwomethodtochecktheresultsofmodelingComparisonbetweenthecalculatedandmeasureddatainliteratureisthemostusuallyemployedtest(exampleoneonSrZrO3)thebestwayistocoupleinteractiveexperimentationandmodeling(exampletwoonKBr-TbBr3)TwoexamplewereusedtoillustratethesestwomethodsStructurebehaviorandthermodynamicpropertiesofSrZrO3KBr-TbBr3PhasediagramandthedecompositionofK3TbBr6TwomethodtochecktheresultExample1:structuralbehaviorandthermodynamic

propertiesofSrZrO3

TwodifferentreviewsaboutthestructurebehaviorofSrZrO3existedinliterature

Onereview:theroomtemperaturestructureofSrZrO3waspseudo-cubic,andthispseudo-cubicstructuredidnotundergoanyphasetransformationuponheatingSecondreview:theroomtemperaturestructureofSrZrO3wasorthorhombic,andtheorthorhombicperovskiteSrZrO3willtransformthroughhighersymmetriesduringheating,eventuallytoidealcubicAseriesofthermodynamicdataavailableinliteraturebutgreatdifferenceexistedDifferentstructure?Effectofimpurities,minordeparturesfromnominalstoichiometry,orchangesinsynthesistemperatures?Example1:structuralbehaviorHowtoidentifyandresolvetheinconsistencybetweenvariouskindsofexperimentaldata?Basictool:thermodynamicmodelingcomplementaryexperimentationHowtoidentifyandresolvethExperimentaldataevaluationandthermodynamicmodelingThermodynamicdataandstructuralinformationevaluation,thustwooptimizationprocedurewereadoptedOneoptimizationprocedure:don’tconsiderstructuretransformation

ThermodynamicmodelingofSrZrO3:

GSrZrO3=a1+b1·T+c1·T·lnT+d1·T2+e1·T

–1(1)Secondoptimizationprocedure:considerstructuretransformation,ThermodynamicmodelingofSrZrO3:similarequationas(1)todescribeorthorhombicSrZrO3pGSrZrO3=oGSrZrO3+ΔH1-T·ΔS1(2)

tGSrZrO3

=pGSrZrO3+ΔH2-T·ΔS2(3)

cGSrZrO3

=tGSrZrO3+ΔH3-T·ΔS3(4)ΔH1,ΔS1,ΔH2,ΔS2,ΔH3,ΔS3

arethecorrespondingenthalpiesandentropiesofthetransformationsThermodynamicmodelingonSrZrO3ExperimentaldataevaluationaComparisonbetweenExperimentaldataandThermodynamiccalculationStructuretransformationandthecorrespondingenthalpyweredetectedbythermodynamicmodelingComparisonbetweenExperimentaPreparethesamplesSolidreactiontoprepareSrZrO3:SrCO3+ZrO2

Heat-treatedat1150,1000,8500CAirquenchedorfurnace-cooledXRDdeterminationExperimentationonSrZrO3PreparethesamplesExperimentaXRDcurve:samplequenchedfrom11500Candfurnace-cooledtoroomtemperatureshowthecubicandorthorhombicstructure,respectively.

TheobservedpatternsfromSrZrO3,showingthefundamentalperovskitereflections.Thepatternswererecordedat850,roomtemperatureand1150oCXRDcurve:samplequenchedfroXRDcurveresultsillustrate:negativethepseudo-cubicSrZrO3inroomtemperature,confirmthestructuretransformationit’squitedifficulttoobtainthetetragonalSrZrO3duetotheimpurity,minordeparturesfromnominalstoichiometryXRDcurveresultsillustrate:ConclusionsThermodynamicmodelingandexperimentationbenefitthestructurebehaviorandthermodynamicpropertiesinvestigationThermodynamicmodelingisbasedontheexperimentalinformationandcanbeusedtoidentifyandresolvetheinconsistencybetweenvariouskindsofexperimentalConclusionsThermodynamicmodelExample2:KBr-TbBr3systemMeasuredKBr-TbBr3phasediagramby

L.RycerzetalTwoeutecticreactionsThreecompoundsK3TbBr3:asolidphasetransitionat691K,meltcongruentlyat983KK2TbBr5:asolidphasetransitionat658K,meltincongruentlyat725KKTb2Br7:formfromK2TbBr5andTbBr3at694K,meltincongruentlyat741KExample2:KBr-TbBr3systemMeMeasuredthermodynamicdataby

L.RycerzandM.Gaune-EscardHeatcapacityofK3TbBr6:thermaleffectatabout691and983KEnthalpyofmixingofliquidat1113K:theminimumlocatedatabout0.3KBrsuggestedtheexistenceofTbBr6-3MeasuredthermodynamicdatabyThermodynamicmodelingofKBr-TbBr3systemthermodynamicmodelingofeachphasePhasewithoutcompositionrange:G(T)functionCompoundswithoutthermodynamicdata:Neumann-Kopprule

K2TbBr5:A1+B1·T+2/3·GKBr(s)+1/3·GTbBr3(s)

KTb2Br7:A2+B2·T+1/3·GKBr(s)+2/3·GTbBr3(s)K3TbBr6withthermodynamicdataandstructuralinformationtwoequationswereusedtodescribetwoformsofK3TbBr6

lGK3TbBr6=a1+b1·T+c1·T·lnT+d1·T2+e1·T

–1

hGK3TbBr6=a2+b2·T+c2·T·lnT+d2·T2+e2·T

–1Thermodynamicdescriptionofliquidphase:associatedsolution(K+)P(Br-,TbBr6-3,TbBr3)Qwasintroducedtodescribeshort-rangeorderaroundK3TbBr6compositionThermodynamicmodelingofKBr-Thermodynamiccalculationandcomparison(Thermo-Calcsoftware)CalculatedphasediagramGoodagreementException:decompositionofK3TbBr6at593KThedetectedthermoeffectintheheatcapacitycurveofK3TbBr6atlowtemperatureAssessedtobestructurechangeKeyexperimentswereconductedtochecktheexistencetemperaturerangeofK3TbBr6ThermodynamiccalculationandKeyexperimentstochecktheexistencetemperatureofK3TbBr6

PreparethesamplesDSCmeasurementsbetweenroomtemperatureand650Kwitharateof1K/minDSCheatingandcoolingcurve:thermaleffectatabout593KResults:K3TbBr6

KBr+K2TbBr5

at593K

DSCheatingandcoolingtracesonK3TbBr6compoundKeyexperimentstochecktheeConclusions

Basedonthemeasureddata,eachphaseinKBr-TbBr3systemwasthermodynamicallymodeling,KBr-TbBr3phasediagramandthermodynamicpropertieswerepreliminarilycalculated.Guidedbythecalculatedphasediagramandthermodynamicproperties,keyexperimentswerecarriedout,thenmodeloftherelatephasesweremodifiedtoexplaintheliteratureandthepresentmeasuredexperimentaldata.ThefinallyobtainedthermodynamicpropertiesandphasediagramweremorereasonableConclusionsBasedonthemeasuSummaries

Twoexamples,i.e.structurebehaviorofSrZrO3andthephasediagramofKBr-TbBr3systemwereprovidedtoillustratetheinteractiveexperimentationandthermodynamicmodelingThermodynamiccalculationisbasedontheexperimentaldataandcanprovideimportantinformationformaterialsexperiments,thusguidematerialsdesign,development,processingandmaterialsunderstanding.SummariesTwoexamples,i.e.sThankYou!WelcometoChina!

ThankYou!WelcometoChinaInteractiveexperimentationandthermodynamicmodelingWeipingGonga,MarcelleGaune-Escardb,ZhanpengJinaaStateKeyLabofPowderMetallurgy,CentralSouthUniversity,Changsha,Hunan,P.R.ChinabEcolepolytechnique,MecaniqueEnergetique,TechnopoledeChateau-Gombert,Marseille,France.TheCODATAconference,Beijing,China,2006InteractiveexperimentationanOutline1.Introduction2.StructuralbehaviorandthermodynamicpropertiesofSrZrO3

3.ThermodynamicmodelingandexperimentationofKBr-TbBr3system4.SummariesOutline1.IntroductionIntroductionPhasediagram’sfunctions:blueprintsorroadmapformaterialsdesign,development,processingandbasicunderstandingvisualrepresentationsofthestateofamaterial:T,P,CThecorrelationbetweenthermodynamicsandphaseequilibriumJ.W.GibbsModerndevelopment:modelingandcomputertechnologyphaseequilibriumcomputercalculationpossibilityCrucialthermodynamicmodelinginbinarysystemcanbeextrapolatedtomulti-componentsystemsQuestion:Canwebelievetheresultsofmodeling?IntroductionPhasediagram’sfuTwomethodtochecktheresultsofmodelingComparisonbetweenthecalculatedandmeasureddatainliteratureisthemostusuallyemployedtest(exampleoneonSrZrO3)thebestwayistocoupleinteractiveexperimentationandmodeling(exampletwoonKBr-TbBr3)TwoexamplewereusedtoillustratethesestwomethodsStructurebehaviorandthermodynamicpropertiesofSrZrO3KBr-TbBr3PhasediagramandthedecompositionofK3TbBr6TwomethodtochecktheresultExample1:structuralbehaviorandthermodynamic

propertiesofSrZrO3

TwodifferentreviewsaboutthestructurebehaviorofSrZrO3existedinliterature

Onereview:theroomtemperaturestructureofSrZrO3waspseudo-cubic,andthispseudo-cubicstructuredidnotundergoanyphasetransformationuponheatingSecondreview:theroomtemperaturestructureofSrZrO3wasorthorhombic,andtheorthorhombicperovskiteSrZrO3willtransformthroughhighersymmetriesduringheating,eventuallytoidealcubicAseriesofthermodynamicdataavailableinliteraturebutgreatdifferenceexistedDifferentstructure?Effectofimpurities,minordeparturesfromnominalstoichiometry,orchangesinsynthesistemperatures?Example1:structuralbehaviorHowtoidentifyandresolvetheinconsistencybetweenvariouskindsofexperimentaldata?Basictool:thermodynamicmodelingcomplementaryexperimentationHowtoidentifyandresolvethExperimentaldataevaluationandthermodynamicmodelingThermodynamicdataandstructuralinformationevaluation,thustwooptimizationprocedurewereadoptedOneoptimizationprocedure:don’tconsiderstructuretransformation

ThermodynamicmodelingofSrZrO3:

GSrZrO3=a1+b1·T+c1·T·lnT+d1·T2+e1·T

–1(1)Secondoptimizationprocedure:considerstructuretransformation,ThermodynamicmodelingofSrZrO3:similarequationas(1)todescribeorthorhombicSrZrO3pGSrZrO3=oGSrZrO3+ΔH1-T·ΔS1(2)

tGSrZrO3

=pGSrZrO3+ΔH2-T·ΔS2(3)

cGSrZrO3

=tGSrZrO3+ΔH3-T·ΔS3(4)ΔH1,ΔS1,ΔH2,ΔS2,ΔH3,ΔS3

arethecorrespondingenthalpiesandentropiesofthetransformationsThermodynamicmodelingonSrZrO3ExperimentaldataevaluationaComparisonbetweenExperimentaldataandThermodynamiccalculationStructuretransformationandthecorrespondingenthalpyweredetectedbythermodynamicmodelingComparisonbetweenExperimentaPreparethesamplesSolidreactiontoprepareSrZrO3:SrCO3+ZrO2

Heat-treatedat1150,1000,8500CAirquenchedorfurnace-cooledXRDdeterminationExperimentationonSrZrO3PreparethesamplesExperimentaXRDcurve:samplequenchedfrom11500Candfurnace-cooledtoroomtemperatureshowthecubicandorthorhombicstructure,respectively.

TheobservedpatternsfromSrZrO3,showingthefundamentalperovskitereflections.Thepatternswererecordedat850,roomtemperatureand1150oCXRDcurve:samplequenchedfroXRDcurveresultsillustrate:negativethepseudo-cubicSrZrO3inroomtemperature,confirmthestructuretransformationit’squitedifficulttoobtainthetetragonalSrZrO3duetotheimpurity,minordeparturesfromnominalstoichiometryXRDcurveresultsillustrate:ConclusionsThermodynamicmodelingandexperimentationbenefitthestructurebehaviorandthermodynamicpropertiesinvestigationThermodynamicmodelingisbasedontheexperimentalinformationandcanbeusedtoidentifyandresolvetheinconsistencybetweenvariouskindsofexperimentalConclusionsThermodynamicmodelExample2:KBr-TbBr3systemMeasuredKBr-TbBr3phasediagramby

L.RycerzetalTwoeutecticreactionsThreecompoundsK3TbBr3:asolidphasetransitionat691K,meltcongruentlyat983KK2TbBr5:asolidphasetransitionat658K,meltincongruentlyat725KKTb2Br7:formfromK2TbBr5andTbBr3at694K,meltincongruentlyat741KExample2:KBr-TbBr3systemMeMeasuredthermodynamicdataby

L.RycerzandM.Gaune-EscardHeatcapacityofK3TbBr6:thermaleffectatabout691and983KEnthalpyofmixingofliquidat1113K:theminimumlocatedatabout0.3KBrsuggestedtheexistenceofTbBr6-3MeasuredthermodynamicdatabyThermodynamicmodelingofKBr-TbBr3systemthermodynamicmodelingofeachphasePhasewithoutcompositionrange:G(T)functionCompoundswithoutthermodynamicdata:Neumann-Kopprule

K2TbBr5:A1+B1·T+2/3·GKBr(s)+1/3·GTbBr3(s)

KTb2Br7:A2+B2·T+1/3·GKBr(s)+2/3·GTbBr3(s)K3TbBr6withthermodynamicdataandstructuralinformationtwoequationswereusedtodescribetwoformsofK3TbBr6

lGK3TbBr6=a1+b1·T+c1·T·lnT+d1·T2+e1·T

–1

hGK3TbBr6=a2+b2·T+c2·T·lnT+d2·T2+e2·T

–1Thermodynamicdescriptionofliquidphase:associatedsolution(K+)P(Br-,TbBr6-3,TbBr3)Qwasintroducedtodescribeshort-rangeorderaroundK3TbBr6compositionThermodynamicmodelingofKBr-Thermodynamiccalculationandcomparison(Thermo-Calcsoftware)CalculatedphasediagramGoodagreementException:decompositionofK3TbBr6at593KThedetectedthermoef