简介:Ithasbeenreportedthatthemainfactorswhichinfluencethepropertiesofself-flowcastableare:1)theparticlesizedistributionand2)thefunctionofdispersantandsurfactant,Inthepresentpaper,theoptimumrangeofparticlesizedistributionandthebestispersantandsurfactantaswellasthefunctionmechanismsarediscussed,Alsoamethodtoeveluateself-flowcastablearegiven.
简介:ThefracturetoughnessofMgOpartiallystabilizedzirconia(MgO-PSZ)hasbeenmea-suredbythehardnessindentationmethod.TheinfluencesofheattreatmentonthefracturetoughnessK1cofMgO-PSZwerestudied,ItwasfoundthatthefracturetoughnessofMgO-PSZcanbegreatlychangedbydifferentheattreatmentprofile.Thefracturetoughnesswasimprovedbytheheattreatmentat1100℃afteragingat1400℃,TherewasthegreatestK1cvalue(11.30MPa.m^1/2)ofthesamplesagedat1400℃for2hfollowedbyasubse-quentannealat1100℃for10h.ThechangesinthemicrostructureofMgO-PSZceramicsagedwithdifferentthermaltreatmentwerestudieddbyuseoftransmissionelectronmicroscopy.
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:Inordertoovercomecastables'innateimperfectionfrombondphase,wereferaso-called"self-bonded"phasetomullitecastableusingsilicasolwiththehelpofsuperfinepowderasthebindrforfullyexertingthemeritoftheperfectintegralityofcastable,There-searchworkdemonstratesthatcomparingwithlow-cementcastable,thiskindof"self-bonded"mullitecastableischarterizebyhavingperfectintegralityofstructureinthewholescopeoftesttemperature,beingverydense,andexcellentinvolumestability,itsporositychangingverylittleandsmoothly,thecoldandhotstrengthesbeinghighandstable,hightemperaturecompressivecreeplittle.Thisisaverypromisingcastablestructuralrefrctory.
简介:Akindofdryrefractorysealingmaterialhasbeendevelopedtorepairthefinecracksincokeovenchamber.Withsilicasandasthemainrawmaterial,thesealingmaterialisblownintocokeovenchamberbycompressedairwhilebeingapplied,andbondedtobricksurfaceorfilledinfinecracksofchamberunderrightpressure.Thephysicalpropertiesofthematerialaresimilartothoseofsilicabricksduringitsapplication.Soitcanbeadaptedtoconditionsofcokeovenandhasgoodservicelife.Thestudyandapplicationresultsofthesealingmaterialaredescribedinthispaper.
简介:AkindofZrO2ceramicmaterialforporousmediaburnerwaspreparedbypolymericspongeprocesswithstartingmaterialsofzircon,zirconiapowder,microsilica,andballclay,andbinderofsilicasolthroughreaction-sintering.Theeffectsofmicrosilicaadditiononcoldcrushingstrengthandzirconia/zirconaddingratioonthermalshockresistancewerestudied.Theresultsshowthattheporousmediamaterialhasproperporosity,highstrength,andexcellentthermalshockresistancewhenzirconiaadditionis85%andzirconadditionis5%.Theperformanceindexesare:porosity82%,coldcrushingstrength3.1MPa,thermalshockresistancemorethan10cycles,andgoodthermalshockresistanceto1500℃flame.
简介:Themicrostructureandslagerosionfractaldimensionofreactioninterfaceofβ-Sialon-Al2O3brickusedin300MtironladleofBaosteelhavebeenstudiedbySEMandXRD.Theresultsindicatedthatβ-Sialon-Al2O3brickexhibitedexcellentslagresistance.Themainwearmechanismofβ-Sialon-Al2O3brickismainlyfromthespallingcausedbythermalmechanicalstressandattackedbyslagsecondly.
简介:ThisworkstudiedthecharacteristicsofSiO2distributionandstructureofsilicatephasesinMgO-ZrO2compositessynthesizedbyrawmaterialsoflightfiredmagnesitendzircon,Theresultsindicatethat30wt%-40wt%SiO2contentinthesystemisexistedintheformofcrystallineofforsterite(M2S),theremainderingofSiOcontent(60wt%0-70wt%)isexistedintheglassphase,Thechemicalcompositionofglassphaseiswellagreedwiththechemicalcompositionofmonticellite(CMS).
简介:IntheprocessofsynthesisofnanometerSiCprecursorswithsol-gelofSiO2andlignin,theproductsofallsizesrequiredcanbecontrolledbytheconcentrationofreac-tants,pH,temperature,ractionandageingtime,andsoon.Thebestconditionsinthisreserchare:theconcentrationofNa2SiO3andorganicmattersare4.50%and26.4%respectively,pH=3.3,T=65℃,ageingtimeis30min,driedat150℃,thesizeofSiCprecursorsisabout2.0μm。
简介:Thecorrosionofrefractoriesresultsfromreactivetransport,namely,transportofagentsandchemicalreactionsoftheseagentswithimpregnatedmedium.Ononehand,thetransportinvolveseitherdiffusionorimpregnationdependingonthestateofthecorrosiveagentsandthemicrostructureofthehostmedia.Ontheotherhand,chemicalreactionsmaybeverynumerousandcomplex.ThisstudyfocusedonthereactiveimpregnationofAl2O3-CaOslagintoporoushighaluminarefractory.Thetransportpropertiesoftherefractorymaterialwereidentifiedbymeansofadedicatedcapillaryrisingtest.ChemicalreactionsbetweenthesolidhighaluminaskeletonandAl2O3-CaOslaginvolvesuccessivedissolution/precipitationmechanismsformingaluminatesoflime.Contrarytothethermodynamicpropertiesofthebinarysystem,thekineticsofthesesolid/liquidreactionsisnotwellknown.Corrosiontestsassociatedwiththequenchingmethod,XRDanalyseswereperformedforabetterunderstandingofthekinetics.Theresultsofthisstudyopenupacouplingapproachforpredictingthecorrosionwearofrefractory.
简介:InordertoimprovethemechanicalpropertiesofSiO2aerogel-glassfibercomposites,effectsofdifferentsolvents(cyclohexane,n-hexane,ethanol,acetone)anddifferentdispersingmodes(planetaryballmilling,ultrasonicdispersionandmechanicalstirring)anddispersingduration(10-40min)onthedispersionofchoppedalkali-freeglassfiberbundleswerestudiedtodeterminethebestdispersionprocess.Onthisbasis,thematerialswerebatchedaccordingtothemassfractionofSiO2aerogelpowdertochoppedalkalifreeglassfiberbundlesof90:10,andacertainamountofzincoxidelight-screeningagentandphenolicresinbinderwereadded.SiO2aerogelglassfibercompositespecimenswerepreparedbydirectaddingchoppedalkalifreeglassfiberbundlesandpre-dispersedchoppedalkalifreeglassfiberbundles,respectively.Thecoldcrushingstrengthandthethermalconductivityatdifferentsurfacetemperatures(300,400,500and600℃,respectively)ofthespecimensweremeasured.Theresultsshowthat:(1)theoptimumdispersionprocessofchoppedalkali-freeglassfiberbundlesisusingethanolassolventandmechanicalstirringfor30min;(2)pre-dispersionofchoppedalkali-freeglassfiberbundleshaslittleeffectonthethermalconductivityofSiO2aerogel-glassfibercompositesbutcanimprovethecoldcrushingstrength.