学科分类
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53 个结果
  • 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。

  • 标签: 木质素 耐火材料 合成 纳米材料 SIC SIO2
  • 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.

  • 标签: 熔盐合成 工业氧化铝 氯化锂 氯化钾 氧化镁 F系统
  • 简介:Cr2O3canbesinteredwellat1500℃incarbon-embeddedconditionorH2atmosphere.Butthehighchromebearingrefractoriescannotreachdensificationwhensinteredat1700℃for10hinweakreducingatmosphereformedbythecombustionoffuel,anditsapparentporosityisabout18%.Thehighchromebearingrefractoriesaremainlyusedincoalgasifiers.Thetemperatureinthefurnaceisabout1500℃andtheproductsareH2andCO,whicharejustthesinteringconditionsofthedensechromerefractorieswithapparentporositylessthan10%.Thehighchromebearingrefractoriesusedincoalgasifiersmaybesinteredagainandthenshrink,destroyingthegasifierlining.Thethermodynamiccalculationshowsthatitissafeaboutthehighchromebearingrefractoriesusedingasifiers.Itisalsoexplainedthatthehighchromebearingrefractoriescan’tbesintereddenselyinweakreducingatmosphereformedbythecombustionoffuel.Thenewsinteringtechnologiescanbeusedtoimprovethebulkdensityofthehighchromebearingrefractories.

  • 标签: 铬质耐火材料 烧结技术 热力学计算 CR2O3 轴承 还原性气氛
  • 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℃.

  • 标签:
  • 简介:ThispapertestifiesthataluminiumandsiliconaswellastheircarbidexandnitridescanreactwithCOincarbon-containingzonetoformAl2O3andSiOgasthroughexperimentandthermodyanmicanalysis,ThegasesdiffusetooxidizedzoneandreactwithoxidizerssuchasCO2,Asaresult,Al2O3andSiO2aredepositedfromthegases,wihichblockthepores,thusreducetheamountofgasdiffusionandincreaseoxidationresistnaceofcarbon-containingmaterials.

  • 标签: 氧化铝 石墨 添加剂 被氧化物质 碳化硅 阻塞孔
  • 简介:SiliconoxynitridewasaddedinshapedAl2O3-SiC-Crefractorymaterialtoimprovetheslagresistanceinthispaper.Optimumaddingquantityofsiliconoxynitridepowderwasalsostudied.TheresultsshowthattheslagresistanceofAl2O3-SiC-Cshapedrefractoryisimprovedwhen2%or3%Si2N2Oisadded.AreasonableamountofSi2N2OaddedintoAl2O3-SiC-Cshapedrefractorycanproducesiliconoxideintotheslag,whichcanimprovetheviscosityofslagandpreventtheslagerosionandpenetration.

  • 标签: SLAG resistance SILICON OXYNITRIDE alumina-silicon carbide-carbon
  • 简介:Thecorrosionofrefractoriesresultsfromreactivetransport,namely,transportofagentsandchemicalreactionsoftheseagentswithimpregnatedmedium.Ononehand,thetransportinvolveseitherdiffusionorimpregnationdependingonthestateofthecorrosiveagentsandthemicrostructureofthehostmedia.Ontheotherhand,chemicalreactionsmaybeverynumerousandcomplex.ThisstudyfocusedonthereactiveimpregnationofAl2O3-CaOslagintoporoushighaluminarefractory.Thetransportpropertiesoftherefractorymaterialwereidentifiedbymeansofadedicatedcapillaryrisingtest.ChemicalreactionsbetweenthesolidhighaluminaskeletonandAl2O3-CaOslaginvolvesuccessivedissolution/precipitationmechanismsformingaluminatesoflime.Contrarytothethermodynamicpropertiesofthebinarysystem,thekineticsofthesesolid/liquidreactionsisnotwellknown.Corrosiontestsassociatedwiththequenchingmethod,XRDanalyseswereperformedforabetterunderstandingofthekinetics.Theresultsofthisstudyopenupacouplingapproachforpredictingthecorrosionwearofrefractory.

  • 标签: 高铝耐火材料 反应机制 浸渍介质 氧化钙 腐蚀剂 氧化铝
  • 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.

  • 标签: silicon aerogel-glass insulating materials alkali-free GLASS
  • 简介:Theroleofnano-SiO2andultra-fineboroncarbideonthepropertiesofalumina-graphitematerialswasinvestigated.Thestudyshowedthattheultra-fineboroncarbideaddedmodifiedthemicrostructureofresidualcarbonandpromotedthechemicalbondbetweenresidualcarbonfromphenolicresinandflakegraphite.Thecarbonwhitecouldstrengthentheresidualcarbonfromphenolicresin.ThesetwoadditivesimprovedthemechanicalpropertiesofAGrefractoriesatbothroomtemperatureandhightemperature,andthermalshockresistancewasimprovednoticeably.Whenthetwoadditivesweredopedtogether,carbonwhitecouldretardtheevaporationofB2O3.Thermalshockresistancewasguaranteedwithasmalleramountofultrafineboroncarbide.

  • 标签: B4C 纳米二氧化硅 SiO2 性质 氧化铝-石墨 白炭黑