简介：HightemperatureoxidationbehavioroftwokindsofnitridebondedSiCbasedrefractorieswasinvestigatedat11001500℃bymeansofX-raydiffractometer,scanningelectronicmicroscopyandthermogravimetry.Theresultsshowthat:(1)withthetemperatureincreasing,theoxidationmassincrementrateofthespecimenincreasesfirstandthendecreases,andoxidationpassivationoccurs;(2)theoxidationresistanceofSiAlONbondedSiCrefractoriesissuperiortothatofSi3N4bondedSiCrefractories;(3)hightemperatureoxidationresultsintheincreaseofcompressivestrengthatroomtemperatureofSiCbasedrefractoriescomparedwithspecimenbeforeoxidation;thecompressivestrengthofSiAlONbondedSiCspecimensoxidizedathightemperaturesdecreaseswiththeincreaseofthetemperatureasaresultofformationandburstofsurfacebubble,whilethedecreaseofcompressivestrengthofSi3N4bondedSiCspecimensoxidizedathightemperaturesisowingtotheincreaseoftheconsistencyofnet-likecrackassociatedwithcristobalitetransformationduringcooling.

简介：Lowcement(LC)andultra-lowcement(ULC)bauxite-SiCcastablesareimportantandhighperformancemonolithicrefiactoriesandtheyhavebeenwidelyusediniron-makingandincineratorlinings.Inthiswork,rheo-logicalbehaviorofLCandULCbauxite-basedSiC-contain-ingcastableshasbeenstudied,includingtheeffectsofSiCcontentandcementcontentonrheologicalpropertiesofthecastables.TheresultsshowthatwithanincreaseofSiCandcementcontent,rheologicalpropertiesofthecastablesdeteriorate.Ontheotherhand,moderateamountsofSiC(4%～8%)andofcalciumaluminatecement(2%～4%)haveveryslightinfluenceonrheologicalproperties,(i.e.whenthecastablesareshearedtheirtorqueandyieldtorqueonlyslightlyincreasewiththeshearingspeed).Therheologicalcharacteristicsofthecastablesfol-lowBinghamfiuidandalwaysshowshearthinningbehav-ior.

简介：ThemullitizationofandalusitefromXinjiang,ChinaandinfluenceofaggregatesonpropertiesofaluminosilicaterefractorieswerestudiedbyXRD,SEM,EDS,DSC.Itwasfoundthatmullitizationwasobviousat1400℃,butconsiderableat1500℃.TherefractorieswithcorundumaggregateshadthehighestRULandthelowestcreeprate,butrefractorieswithbauxiteaggregateshadthelowestRULandthehighestcreeprate.

简介：Theeffectsofcorundum,magnesiaandspineladditionsonrheologicalpropertiesofmatrixofbauxite-basedcastableswerestudiedusingbauxite,fusedwhitecorundum,magnesia,spinel,microsilica,ultra-fineα-Al2O3andcementasstartingmaterialsandtrimericsodiumphosphateasdispersant.Theresultsshow:(1)thematrixslurryofbauxite-basedcastablesbelongstoBinghamfluidandshowsthixotropybehavior;(2)appropriatecorundumadditionimprovesrheologicalpropertiesofthematrix;(3)magnesiaadditionisdetrimentaltomatrixrheologicalproperties;(4)spineladditionhasslightlynegativeeffectsonmatrixrheologicalproperties.

简介：Newcarbonbondedfilterswith'activeandreactivecoatings'forhigherfiltrationefficiencyofaluminabasedinclusionsaswellasnano-engineeredfilterswithnano-scaledadditivesareexploredwiththeaidofimpingementtestsandareevaluatedaccordingtotheircoldcrushingstrengthsatroomtemperature.ThecombinationofcarbonnanotubesandaluminananosheetsadditivesleadstoinsituformationofAl3CON.Boththenanoscaledadditivesaswellastheextraalumina'active'coatingleadtoimprovedmechanicalperformanceofthecarbonbondedfiltersandopenthehorizonforfiltermacrostructureswithhigherfiltrationcapacitiesinmeansofbiggerdimensions.InafurtherstepMWCNT(multiwalledcarbonnanotubes)incombinationwithasyntheticpitchhavebeenusedasafunctionalcoatingonthesurfaceofaluminacarbonbondedfilters.Thesefiltershavethenbeenevaluatedalsowithuncoatedfiltersinaspecialcastingsimulatorandtheinteractionsbetweensteelandfilteringmaterialhavebeeninvestigated.

简介：ThemagnesiabasedcurablespecimenswithdifferentSi3N4contentswerecastedusingsinteredmagnesite(w(MgO)=95%)asstartingmaterial,SiO2micro-powderasbinder,0.3%,4%and5%β-Si3N4powderreplacingtheequaladditionofmagnesiapowderrespectively.Theslagresistancetestwascarriedoutat1550℃for3husingBaosteeltundishslagandstaticcruciblemethod.Theresultindicatesthat:introducingSi3N4couldobviouslyimprovetheslagresistanceofMgObasedcastable,whichincreasedwithincreasingSi3N4.DenseSiO2sinteredlayerformedonthesurfaceofmagnesiabasedcastablebecauseoftheoxidationofSi3N4addition,whichcanpreventthefurtherslagpenetration.Inthedeepinnerofcastable,thepartial-pressureofoxygenwasverylow,soSi3N4canexiststably.Meanwhileinreducingatmosphere,Si3N4washardtobesintered,whichresultedinthelooseinteriorstructureofMgObasedcastable.

简介：Thermalshockresistantpropertiesofreactionsinteredbauxite-basedβ-Sialonbondedcorundumhavebeeninvestigated,andtheresultsarecomparedwiththoseofAl2O3basedcounterpart.Itisfoundtheyallhaveverygoodthermalshockresistance.Theirresidualstrengthratiosafteronethermalshockcycleat△T=1200℃and△T=1350℃are61%～73%and53%～65%respectively.Theircriticaltemperaturedifference(TSR)is600℃～800℃.TSRparametersarecalculatedbasedonthermalexpansion,modulusofelasticity,andfracturetoughnessdetermined.ThereasonsforimprovingTSRofthesecompositematerialsarediscussed.

简介：MajorenvironmentalproblemsrelatedtorefractoriesarediscussedbasedontheirhistoricalstudiesmostlyinJapan.Thoseissueshavebeenexperiencedinawiderangeofindustrialscenes,fromprocessingrawmaterials,makingrefractoriestoreliningfurnaces,handlingafter-userefractories.Thekeysubstancesdealtwithinthispaperinclude,forexample,suspendedparticulate,SOxandotherexhaustgaseousemissions,hexa-valentchromium,anddioxin.Themeasuressofartakentoavoidorreducetheirinfluencesuponenvironmentsaredescribedwithsomefutureproblemstobetackled.

简介：Apreliminaryapplicationofthedigitalimagecorrelation(DIC)ispresentedaimingtodetectandanalyzecracknetworkswhichareinducedbystressesarisingduringcuringanddrying(CD)ofMgOcontainingrefractorycastableslabs.SurfaceimagesofcastablesamplesplacedinaspeciallydesignedclimaticchamberwererecordedovertheCDstageswithadigitalcameraandprocessedbytheDICtechniquetomeasurethedisplacementfields.Post-processingDICresultswerecarriedouttoestimatethelength,orientationandopeningofcracksinthenetworks.Themethodologyishighlightedandthefirstexperimentalresultsareshownpointingoutitsfuturepotentialtobetterunderstandtheeffectofthephysicalaspects(particlesize,chemicalanalysis,temperature,etc.)andthestructuralones(slabshapeandsize)onprocessingandperformanceofadvancedrefractorycastables.

简介：NickelnitratewasintroducedintocarbonblocksbyusingECAaggregatesascatalyst-carrier.TheNi-containinganthraciteaggregateswerefirstlypreparedbymixinganthraciteaggregatesinnickelnitrateethanolsolutionandthenincorporatedintocarbonblocksafterpre-treating.Thephasecomposition,microstructureandpropertiesofallcarbonblocksfiredat1000℃or1400℃inacokebedwerestudiedwiththeaidofanX-raydiffractomer,afieldemissionscanningelectronmicroscope,amercuryporosimetryandalaserthermalconductivitymeter.TheresultsshowedthattheadditionofNi-containinganthraciteaggregatespromotedtheformationofone-dimensionalnanocarbonandβ-SiCwhiskersat1000℃andthegrowthofβ-Sialonat1400℃,respectively.Moreover,thecoldcompressivestrengthandmicroporositycharacteristicsofthecarbonblockswiththeadditionofNi-containinganthraciteaggregateswereenhancedandthethermalconductivitywasremarkablyimprovedattributingtothehighheatconductivenetworkformedbytheceramicphases.

简介：Cr2O3canbesinteredwellat1500℃incarbon-embeddedconditionorH2atmosphere.Butthehighchromebearingrefractoriescannotreachdensificationwhensinteredat1700℃for10hinweakreducingatmosphereformedbythecombustionoffuel,anditsapparentporosityisabout18%.Thehighchromebearingrefractoriesaremainlyusedincoalgasifiers.Thetemperatureinthefurnaceisabout1500℃andtheproductsareH2andCO,whicharejustthesinteringconditionsofthedensechromerefractorieswithapparentporositylessthan10%.Thehighchromebearingrefractoriesusedincoalgasifiersmaybesinteredagainandthenshrink,destroyingthegasifierlining.Thethermodynamiccalculationshowsthatitissafeaboutthehighchromebearingrefractoriesusedingasifiers.Itisalsoexplainedthatthehighchromebearingrefractoriescan’tbesintereddenselyinweakreducingatmosphereformedbythecombustionoffuel.Thenewsinteringtechnologiescanbeusedtoimprovethebulkdensityofthehighchromebearingrefractories.

简介：Inthisstudy,inordertoevaluatetheperformanceofhomogenizedbauxite,twoAl_2O_3-SiC-Ccastableswerepreparedusinghomogenizedbauxiteandbrownfusedcorundumasaggregates,respectively.5mass%andalusitewasintroducedintothetwocastablessoastoresearchtheeffectandmechanismofandalusiteinAl_2O_3-SiC-Ccastables.Theresultsshowedthat:(1)comparedwiththebrownfusedcorundumbasedcastables,thehomogenizedbauxitebasedcastableshadhighercoldstrengthafterheattreatment,butlowerhotmodulusofrupture;(2)additionof5mass%andalusitecouldenhancethecoldandhotmodulusofrupture,improvethethermalshockresistance,andoptimizethemicrostructureofspecimens;(3)themullitizationofandalusitewasnotobviousinthecastablesfiredat1100-1400℃.

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

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