简介：Nanoscalemullitepowderweresynthesizedviasolgel-SCFDandmiddletemperaturetreatmentbyusingAIP(aluminum-isopropoxde)andTEOS(tetraethylorthosilicate)asstartingmaterials.Bothofthebinaryaerogelofalumina-silicaandcalcinednanoscalematerialswereinvestigatedbyusingTG-DSC(thermogravimetry-differentialscanningcalorimeter),TEM(transmissionelectronmicroscope),XRD(X-Raydiffractometer)andspecificsurfaceareaandporosimetry.TG-DSCindicatedtheremovalofmostofthevolatiles,i.e.15.98%uptoabout700℃,andintheDSCcurve,existenceoftwoexothermicpeakatabout445℃and1015℃maybeduetothecrystallizationofSi-O-Al-Oindiphasicgelsandmullitizationandasmallendothermicpeakatabout805℃indicatedthedecompositionofstructuralwatermolecules.OnthecolligationoftheresultsofTG-DSC,XRDandTEM,thebeginningtemperatureofmullitizationinAl2O3-SiO2aerogelsystemcanbeconfirmedatabout1015℃.XRDresultsalsoshowedtheformationofmulliteattherange1100-1200℃.TEMandsurfaceareaandporosimetryresultsshowedthatthenanosizedmullitewerecalcinatedat1100and1200℃exhibitedsize30nmand50nm,specificsurfacearea138.91m^2/gand95.81m^2/g.

简介：Thesynthesisofβ'-sialonpowderbycarbothermicreductionofclayfollowedbynitridationhasbeencarriedout.Theeffectofchargemixture,temperature,holdingtimeandnitrogenflowrateonsynthesiswasexamined.ThefiredsamplewasidentifiedbyXRDandthenitrogencontentoffiredsamplewasmeasured.Thesynthesisprocessofsialonpowderwasdescribed.

简介：Thepropertiesandlowandmediumtem-peraturebondingmechanismsofvariedtypesofSiO2ultrafinepowderusedinceramicandrefractoryandthetemperatureatwhichSiO2ultrafinepowderbegantoreactwithAl2O3werestudied,AndinitialresearchesoneffectsofultrafinepowdersofAl2O3,SiC,3Al2o3·2SiO2,MgO·Al2O3andZrSiO4onpromotingsinteringweremade.TheresultsindicatedthatamongvarioustypesofSiO2ultrafinepowder,non-crystalsil-icaultrafinepowderwacharacterizedbyitsstructureandproperties,Itcouldyieldconsid-erablesilicagelonitssurfaceatlowtempera-ture,whichthendehydratedandformedSi-O-Sibond,therebydevelopinganettystructurethatcausedhigherbondstrengthatlowandmediumtemperaturesincethenettystructurebasicallyremperaturesincethenettystructurebasicallyreainedastermperturerising.SiO2ultrafinepowderbegantoreactwithAl2O3at700℃,Allofothertypesofultrafinepowderhadeffectsonstimulatingsintering,buttheeffectsweresignificantonlywhentheparticlesizeofultrafinepowderwaslessthan5μm。

简介：TheCW-CO2laserdrivengasreactionwasappliedtopreparenano-sizedSiCpowder,SiH4andC2H4ofhighpurties,asstartingmaterials,weremixedtacertainrationandintroducedintotheresactioncell.Thegasesflewacrossthelaserbeamorthogonallyandthuswereheatedbylaserbeam.Thenano-sizedSiCultrafinepowderwswereformedthroughthermicgasreation.Thefinalproductivityofthisprocesswas97%,Theobtainedpowderswerecharacterizedandanalyzed.ChemicalanalysisrevealedthattheSiCcontentwas95.38wt%,Oxygen,theprimaryimpurity,weighted1.32%whiletraceimpurities,suchascalcium,magnesiumandothermetals,wereonly0.03%,XRD,XPSandTEMindicatedthatthpowderparticleswerenearlysphericalandnotagglomerated.Theparticlesizerangedfrom10nmto25nmwithanaverageof15nm,Theparticlestredtobenoncrystalline.

简介：

简介：Inthispaper,theinflucnceofchiefprocessparametersontheontinuousproductionofSi3N4powderbyrenitridationhasbeenstudied,Thesutiableprocessparametershavebeenfound,andhighqualitySi3N4powderhasbeendeveloped.

简介：TheinfluenceofthreedifferentAl2O3powderonself-flowingaluminacastablewasstudied.MaximumcompactionofsamplewascomputedbyAndresenEquation.TheresultshowedthattheAl2O3powder,whichhasmuchsmallerparticlesize,couldimprovethemicrostructureandthemechanicalpropertiesofcastableunderroomtemperatureandhightemperature.Withthesamepowdersize,theroomtemperaturestrengthofthecastableaddedwithAl2O3powderproPertiesofwhichwerealteredbyaddingmineralizingagent,washigherthanthatofthecastableaddedwithcommonAl2O3powder,buttheflowabilityofthesethreedifferentcastablewasalmostthesame.

简介：MoltensaltsynthesisofMgAl2O4powderfromindustrialaluminaandlightcalcinedMgOinKCl,LiCl,andKCl-LiClmedia,andtheinfluenceofKFat500-1000℃wereinvestigated.SynthesizedpowderswerecharacterizedbymeansofXRD,laserparticleanalyzer,andSEM,andthesynthesismechanismofMgAl2O4wasdiscussedaswell.Theresultsshowthat(1)themoltensaltcomposite(KCl-LiCl)ismorefavorableforthesynthesisofMgAl2O4thansinglemoltensalt(LiClorKCl),andLiClismorefavorablethanKCl;(2)KFcanacceleratetheformationofMgAl2O4anddecreaseitsformingtemperature;(3)synthesisofMgAl2O4powderinthemoltensaltswithoutKFiscontrolledby'template-growth'mechanism,butinthemoltensaltswithKF,itiscontrolledby'template-growth'and'dissolution-precipitation'mechanism.

简介：ZrN-basedcompositesweresynthesizedfromzirconiaviaaluminothermicreductionandnitridationproceswithAlpowdersandMgOasthereductantandsinteringaids,respectively.ZrN-basedcompositesarepromisingforapplicationintherefractorymaterialsorotherhightemperatureindustryfields.TheeffectsofextraAlpowderonphysicalproperties,phasetransformationandmicrostructureswereinvestigated.ProductswithdifferenphasecompositionandmorphologieswereobtainedwithdifferentAlpowdersadditions.TheproductswerecomposedofZrN,ZrO_2,MgAl_2O_4,andZrAl_3O_3Nbyaluminothermalreductionandnitridationofzirconiawith0%extraAlpowdersaddition.ThediffractionpeaksoZrNwerethestrongestwhilepeaksofZrO_2vanishedwith6%extraAladdition.ThethermodynamiccalculationindicatedthatintroducingMgOintothesystemcouldpromotethereactionprocess.

简介：

简介：

简介：Siliconcarbide(SiC)-alumina(Al_2O_3)-mullite(Al_6Si_2O_(13))compositepowderwassuccessfullysynthesizedat1550℃for5hviacarbothermalreductionreaction,andtheeffectsofvariousmassratiosofactivecarbontoflyash(0.38,0.44and0.58)onthephasecompositionandmicrostructureofproductswereinvestigated,andtheformationprocessofthepowderwasalsoanalyzedindetail.Theproductsmainlyconsistofβ-SiC,α-Al_2O_3,Al_6Si_2O_(13)andFeSi.IncreasingcarboncontentfavorsthedecompositionofAl_6Si_2O_(13)andformationofSiC.Theaverageparticlesizeofβ-SiCandα-Al_2O_3isabout1μmandthatofAl_6Si_2O_(13)is5-10μm.TheformationprocessofSiC-Al_2O_3-Al_6Si_2O_(13)powderincludesthedecompositionofmulliteinflyashandformationofSiC.