真空冷凍干燥法制備納米氧化鋁粉體的研究.pdf

1、東北大學碩士學位論文真空冷凍干燥法制備納米氧化鋁粉體的研究姓名：曾方允申請學位級別：碩士專業(yè)：流體機械及工程指導教師：張世偉20040201東北大學碩士學位論文AbstractStudyORNanometerAluminaPowdersPreparationbyVacuumFreezedryingProcessAbstractAsaveryimportantllano—material，Nanometeraluminahasbeenap

2、pliedinmanyfieldssuchaselectronics，chemistryengineeringfineceramicandaerospaceindustry，whichmakesthemanufacturingtechnologyofits塒_acerial——thenartosizedaluminapowdenr—～becomeoneofthehottopicsinthescientificresearchfields

3、Amongmanymanufacturingtechnologiesfornanometerpowders，vacuumfreezedryingisproventobeasuperioroneforthepowderspreparedbyithavemanyadvantagessuchasuniformparticlemorphology，lessagglomerates，nanometersize，narrowsizedistribu

4、tion，lli曲purityandhighchemicalhomogeneity，etcItCanbepredictedthatvacuunlfieezedryingtechnologywillplayvitalrolesontheadvancedareassuchasbioengineering，microelectronics，aerospaceindustry，etcIn吐正Sthesis，fwst，thefeaturesand

5、theusesofnanometeraluminaandsomemanufacturingmethodsfornanometeraluminapowdersareintmduced；principlesandcharacteristicsofvacuumfreezedryingmethodfornanometerpowdersaredescribed；developmentandcurrentstatusofthismethodares

6、unlmarized；theproblemstosolvearegiven；thetrendofthemethodispredictedThenthefreezingprocessofprecursorsolutionisstudiedtheoreticallyTheaimsandimportanceoffreezingprocessaregivenTheideaispresentedthatinordertoacquireunifor

7、m，nanosizedandchemicallyhomogeneouspowders，precursorsolutionmustbefrozenrapidlyenoughteducesolutesegregationtoapermissiblelimitHeattransfermodelforwholefreezingandsprayfreezingareestablishedrespectivelyExpressionsoftempe

8、raturedistribution，timeneededinfreezingandinterfacevelocityareobtainedbycalculatingMasstransfermodelforsolutesegregationiSconstructedandexpressionofcriticalrateofsolutediffusioniSgivenBycomparingsolid—liquidinterfacevelo

9、citytocriticalrateofsolutediffusion，arelationexpressionoftheprocessingparameterscorrespondingtoacertainpermissiblelimitsofsolutesegregationisgivenanditscorrespondingtheoreticalphasediagramforfrozensolutionisconstructedIt