莫來石復相納米晶的水熱制備研究.pdf

1、桂林理工大學碩士學位論文莫來石復相納米晶的水熱制備研究姓名：敖寒梅申請學位級別：碩士專業(yè)：材料學指導教師：陳南春20090401桂林理工大學碩士學位論文AbstractComparedwithnormalmullite，thenanomullitematerialshavebettermaehinabilitymechanicsperformance，lowthermalexpansionpropertyandthermalstabil

2、ityAccordingtotheresourcecharacteristicofnaturalkaolinespeciallyitscomposition，themultiphasemullitenanocrystalscouldbesynthesizedfromrawnaturalkaolinonceitisfirstprocessedbypropertechnologySeveraltechniqueshavebeenusedfo

3、rthepreparationofmultiphasemullitenanocrystals，amongthose，hydrothermalmethodformullitepreparationisagoodapproachvvitllrespecttoeconomicconsiderationsFurthermoreitisalowcostprocessandasimpletechniquebywhichthepreparedpowd

4、erhasgoodshapeandCanbecontrolledeasilyInthisresearch，themullitenanocompositewassynthesizedthroughanopen—systemhydrothermalcrystallizationmethodundernormalpressureusingMaoming，Guangdongkaolinasrawmaterials，whichwasfirstpr

5、ocessedbybothoxidationreductionfiningmethodandconventionaljarositetechniquestemoveorganicmatterandotherimpuritiesThesamplespreparedindifferentconditionswereinvestigatedandanalyzedusingTGDSC，Xraydiffraction(xRo)andscannin

6、gelectronmicroscope(SEM)Theinfluencesofhydrothermalparameterssuchasdifferentagitationways，theconcentrationofNaOH，holdingtime，crystallizationtemperatureandprecursorconcentration，etconproducts’grainsizeandmorphologywerestu

7、died，andboththermodymicsandkineticswerestudiedthroughexperiment，furthermore，fromtheviewpointofthegrowthunittheorymodelofanioncoordinationpolyhedron，thenucleationandgrowthmechanismsofnano—crystalswerediscussedTheresultsar

8、easfollows：(1)Thewhitenessofkaolinincreasesfrom568％to802％afterremovingimpurityAndinthefinedsamples，thecontentofSi02andA1203are4506％，3537％，respectively(2)Afterstudyingthemulliteprecursorpreparedindifferentconditionboththe

9、thermodymicsandkineticsofmultiphasemullitenanocrystalspreparedfromprecursorhavebeenstudied，alsothenucleationandgrowthactiveenergywerecalculated，theyare2176kJ／mol，1563kJ／mol，respectivelywhichprovidetheoreticaldatabasisfor

10、theafterwardexperiment，andenrichtheexperimentaldataofmullitecrystallizationdynamicprocess(3)Tlleoptimumproductionconditionswereobtainedthroughhydrothermalexperiment，whichshowsasfollows：agitationwayfirstfastandthenslow；th