高取向Si-,3-N-,4-陶瓷-α-Si-,3-N-,4-晶須復(fù)相陶瓷的制備與性能.pdf

1、武漢理工大學(xué)博士學(xué)位論文高取向SiN陶瓷αSiN晶須復(fù)相陶瓷的制備與性能姓名：畢玉惠申請(qǐng)學(xué)位級(jí)別：博士專業(yè)：材料加工工程指導(dǎo)教師：張聯(lián)盟20080401武漢理工大學(xué)博士學(xué)位論文AbstractHighorientationSi3N4ceramicshavemanyexcellentproperties，suchas，higllfracturetoughness，flexuralstrength，thermalconductivityVi

2、ckershardnessandgoodwearresistanceSoitcanbeusedasengineparts，wire—drawingdies，capacitorsandmatrixmaterialsinthefieldofhi曲一performancemicroelectronicsAtpresent，thehighorientationSi3N4ceramicshavebeenmadebyadding3Si3N4powd

3、ersorpSi3N4whiskersInthepaperSi3N4ceramicwithalignedandelongatedgrainsareprepared，whichhavegoodproperties，byaddingaSi3N4whiskersandusingtapecastingandhotpresssinteringtechniques，whichmakeaSi3N4whiskersaligningalongonedir

4、ectioninthematrixInthestudya—Si3N4whiskersusedareproducedourselvesbythermaldecompositionofSi(NH)2Thediameterof0tSi3N4whiskersis01一101xm，andthelengthisabout10“40肛mInfluencefactorssuchastheappropriateintroducingmethodthatc

5、ouldinfluencethegrowthofwhiskers，thetemperatureofcrystallizationtreatment，residualcarbon，asmallquantityofoxygen，thecruciblemadebyA1203materialsandfurnacetubesareanalysedThetapeswithaligneda—Si3N4whiskersaremadebytapecast

6、ingtechniqueTherearethreekeyquestionsabouttapecastingtechniquesolvedinthepaper：(1)BydetectingtheeffectofdispersantonZetapotentialofsiliconnitridepowders，thecontrolledrangeofthepHvalueoftheslurryareconfirmed；(2)Theadditiv

7、esandtheoptimalcontentareoptimizedbystudyingtheviscosityTheslurrycontaining0【一Si3N4whiskerssuitablefortapecastinghavegooddispersityandstability；(3)Abaffleplateisaddedbeforethebladeofthetapecastingmachinetomakea—Si3N4whis

8、kersalignunidirectionallyinthetapeThetapewithuniformthickness，smoothsurface，goodflexibilitycertainstrength，isobtainedfinallyThegreenbodymadebystackingalignedthetapesaresinteredat1350“C，一1600“Cand30MPaandthesamplesofwitha

9、lignedgrainsaremadeTheeffectofthecontentofQ—Si3N4whiskersandthesinteredtemperaturearestudiedandthedensityofcompactSi3N4ceramicsis323g／cm3Theresultsdemonstratethatthedensificationofthesamplesisrealizedbyliquidphasesinteri