Densification ability of combustion-derived Al2O3 powders.pdf

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1、Availableonlineatwww.sciencedirect.comCeramicsInternational35(2009)1173–1179www.elsevier.com/locate/ceramintDensificationabilityofcombustion-derivedAl2O3powdersIbramGanesha,b,PaulaM.C.Torresb,J.M.F.Ferreirab,*aCentreforAdvancedCeramics,InternationalAdvancedResearchC

2、entreforPowderMetallurgyandNewMaterials(ARCI),Hyderabad500005,A.P.,IndiabDepartmentofCeramicsandGlassEngineering,CICECO,UniversityofAveiro,AveiroP-3810193,PortugalReceived1April2008;receivedinrevisedform12May2008;accepted30May2008Availableonline19July2008AbstractNa

3、nocrystallineAl2O3powderscontainingdifferentamountsofMgO(0.1–5.0mol%)oraddedboehmite(AlOOH)havebeensynthesizedbycombustionsynthesisfromaluminiumnitrateandmagnesiumnitrate,usingureaorsucroseasfuels.Theassynthesizedaluminapowdersweredeagglomerated,compactedbydrypress

4、ingandsinteredat16258Cfor2h.Forcomparisonpurposes,acommercialhighpuritya-Al2O3powder(ACC)wasalsoprocessedfollowingthesameroute.Thesinteredmaterialswerecharacterizedforbulkdensity(BD),apparentporosity(AP),andwaterabsorption(WA)capacity,microstructureusingSEM,andXRDp

5、hasecomposition.Incomparisontoboehmite,theMgOhadaconsiderableeffectonthedensificationbehaviourofcombustion-synthesizedpowder.#2008ElsevierLtdandTechnaGroupS.r.l.Allrightsreserved.Keywords:D.MgO;Combustionsynthesis;a-Al2O3;Boehmite;Sucrose;Urea;Sinteringbehaviour;Mic

6、rostructure1.Introductionnanocrystallinealuminapowders.Literaturereports[6–8]havesuggestedthatforobtainingdensenanocrystallinealuminaAluminaisoneofthemostimportantoxideceramicswithaproducts,eitherthetransformationofg-toa-phasehastobewiderangeofuses,includinghigh-te

7、mperatureapplicationsandarrestedornanocrystallinea-Al2O3powdershavetobeused.Inamicroelectronics.Nowadays,thenanocrystallinematerialsarerecentwork,KumagaiandMessing[6]densifiedaluminareceivingagreatdealofattentionwithabeliefthattheirceramicstofullextentwhilekeepinggr

8、ainsize<0.5mmbymechanicalpropertiesaregreatlyaffectedbythepresenceofusingboehmitesol–gelsseededwith<2.0wt.%a-aluminaextremelyfinecrystalliteswitht