堇青石透波材料的研究與制備.pdf

1、⑨天拳大摹碩士學(xué)位論文學(xué)科專業(yè)：材料學(xué)作者姓名：謝志勇指導(dǎo)教師：梁輝副教授工油士出Z“rr六“Ⅱ士AbstractAsolutionwithcordieritestoicbiometricTEOS，magnesiumnitrateandaluminumnitrateThesolutionwasabsorbedbycarbonblackpowderandformedamixture。Amorphousnanoparticlesofcord

2、ieriteprecursorweregainedbyheattreatingthedriedmixtureat700℃Afterthecrystallizationof0一quartz，MgOA1203spinelandtheappearanceanddisappearanceofanintermediatephase(sapphirine)，wholetheprecursorpowdertransformedintoq—cordie

3、riteThecordieriteprecursorwaspreparedbysolgelprogressandthedensepurecordieriteceramicswasobtainedTheTEOShydrolyzedfor24h，Stoichiometricmagnesiumnitrateandaluminumnitrate，andsomecarbamidewerediSSOlvedinthesolutionofCH3CH2

4、0H—H20Then，thesolutionwasheatedat100℃DuringthisprocessthecarbamidehydrolyzedandproduceduniformlydispersedOH—thatcontributedtothegelatinizationofthesolutionTheXRaydiffractionstudiesonthepowdercalcinedatdifferenttemperatur

5、esfor1hindicatedthatamorphousmatrixcrystallizedintou—cordieritearound1000℃directlyAt1250℃themainphasewasⅡ一cordieriteandasmallamountofspinelexistedAfterheattreatmentat1350℃wholethepowderwasaeordieriteThepowdercalcinedat70

6、0℃for1hwasmoldedthensinteredbetween1200～1350℃Thehighestdensityofthesamplesreachedto99％Afterstudyonthedensificationprogressofpurecordieriteceramics，aconclusioncanbemadethattheporositydecreasetOacriticalvalueattowtemperatu

7、reisoneofthemostimportantfactorsofpreparingdensecordieriteceramiCSThestartingpowderinthisworkwasmadebysol—gelprocessandcordieriteceramicswithgoodperformancewasobtainedbyliquid—phase—sinteringThecomposition，fracturebehavi

8、or，dielectricpropertiesandmicrostructureofthematerialsystemwereinvestigated。Theresultsshowthatliquid—phase—sinteringvariedthecellparameters，andasaresnlt，affectedthemechanicalproperty，dielectricpropertiesandthermalconstan