简介：Refractorymaterialsaresubjectedtomechanicalandchemicalloadsduringapplication,whichrespectivelyleadtofractureandcorrosion.Theunderstandingofthemechanicalfractureandthemicrostructuralmodificationafterprogressivethermalshocksisnecessaryforthesuitabledesignofhighperformancerefractorymaterials.Thefractureprocesszonecanbedividedintotwoareas,wheredifferenttougheningmechanismsarelikelytotakeplace:thecracktipandthefollowingprocessregioncalledwakeregion.Inthisstudy,theemphasisislaidonthemicrostructuralmechanismsoccurringinthewakeregionofthecrackandthecracktip.Therefore,functionalaggregates,namelyfusedeutecticaggregatesofAl2O3-ZrO2-SiO2andAl2O3-ZrO2,andandalusite,areaddedtoamodelhighaluminacastableformulationbasedontabularalumina.Thediscrepancyinthermalbehaviorbetweenaggregatesandmatrixaswellasphasetransformationsuchasmulliteformationfavorfurtherthenucleationofmicrocracksthatreducethestressfieldatthelevelofthecracktip.Twodifferentgrainfractionsoftabularalumina(0.2-0.6mmor2.24-3.00mm)aresubstitutedbythesefunctionalaggregates.Aftersinteringat1500℃for6h,thesamplesarequenchedupto10timesinairwithoutpressurefrom950℃toroomtemperature.Theresultingelasticpropertiesareexaminedaftereachthermalshockcycle,aswellastheresidualbendingstrengthafter0,1,3,5,7and10thermalshocks.TheseresultsarecorrelatedwithScanningElectronMicroscopyanalysesafterthedifferentthermalshockcycles.

简介：ThermaldecompositionofformicacidonSiO_2,CeO_2andγ-Al_2O_3wasstudiedasanelementarystepofreversewater–gasshitreaction(RWGS)oversupportedAucatalysts.γ-Al_2O_3showedthehighestCOselectivityamongthetestedoxidesinthedecompositionofformicacid.Infraredspectroscopyshowedtheformationoffourformatespeciesonγ-Al_2O_3:threeη~1-typeandoneμ~2-typespecies,andtheseformatesdecomposedtoCOat473Korhigher.Au-loadedγ-Al_2O_3sampleswerepreparedbyadepositionprecipitationmethodandusedascatalystsforRWGS.ThesupportedAucatalystgaveCOwithhighselectivityover99%fromCO_2andH_2,whichisattributedtotheformationofformatesonAuandsubsequentdecompositiontoCOonγ-Al_2O_3.

简介：Theroleofnano-SiO2andultra-fineboroncarbideonthepropertiesofalumina-graphitematerialswasinvestigated.Thestudyshowedthattheultra-fineboroncarbideaddedmodifiedthemicrostructureofresidualcarbonandpromotedthechemicalbondbetweenresidualcarbonfromphenolicresinandflakegraphite.Thecarbonwhitecouldstrengthentheresidualcarbonfromphenolicresin.ThesetwoadditivesimprovedthemechanicalpropertiesofAGrefractoriesatbothroomtemperatureandhightemperature,andthermalshockresistancewasimprovednoticeably.Whenthetwoadditivesweredopedtogether,carbonwhitecouldretardtheevaporationofB2O3.Thermalshockresistancewasguaranteedwithasmalleramountofultrafineboroncarbide.

简介：摘要：在这份报纸，试验性的研究被进行以便从高氧化铝的苍蝇灰直接测试sintering多铝红柱石的可行性，没有增加任何额外的材料。结果证明在大多数sintered样品的多铝红柱石内容是超过70%。从beneficiated苍蝇灰的样品sintered在一样的合成条件下面从同样收到的苍蝇灰比那些有多铝红柱石的一个更高的内容。为了获得一个平等者，多铝红柱石总计，更高的sintering温度比为同样收到的苍蝇灰为beneficiated苍蝇灰被需要。就sintered多铝红柱石的物理性质而言，有利sintering温度是1400

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