简介:Theroleofnano-SiO2andultra-fineboroncarbideonthepropertiesofalumina-graphitematerialswasinvestigated.Thestudyshowedthattheultra-fineboroncarbideaddedmodifiedthemicrostructureofresidualcarbonandpromotedthechemicalbondbetweenresidualcarbonfromphenolicresinandflakegraphite.Thecarbonwhitecouldstrengthentheresidualcarbonfromphenolicresin.ThesetwoadditivesimprovedthemechanicalpropertiesofAGrefractoriesatbothroomtemperatureandhightemperature,andthermalshockresistancewasimprovednoticeably.Whenthetwoadditivesweredopedtogether,carbonwhitecouldretardtheevaporationofB2O3.Thermalshockresistancewasguaranteedwithasmalleramountofultrafineboroncarbide.
简介:Inthepresentpaper,novelsidewallmaterialsforaluminumreductioncellwerepreparedinairusingmagnesiaandmagnetiteasstartingmaterials.ThesinteringbehaviorsofthespecimenswereinvestigatedbymeansofX-raydiffraction(XRD)andscanningelectronmicroscope(SEM).AndcorrosiontestsinaNa_3AlF_6-AlF_3-K_3AlF_6bathwereconductedtoevaluatetheelectrolytecorrosionresistance.TheresultsshowthattheFe_3O_4phaseistransformedintoFe_2O_3athightemperatures,whichinturnreactswiththeMgOaddedtoformMgFe_2O_4spinel.AndwithincreasingtheMgOcontentfrom0to30mass%,densificationofthespecimensdecreasesmainlyduetolargervolumeexpansionresultingfromformationofmoreMgFe_2O_4.ThecorrosiontestsshowthatcorrosionlayersareproducedinalltheMgOaddedspecimens.However,forspecimenscontainingMgFe_2O_4phaseonly,Mg(Al,Fe)_2O_4compositespinellayersarealsogenerated,whichremarkablyimprovethecorrosionresistanceofthespecimens.
简介:AnO'-Sialon-Al2O3compositerefractorywaspreparedbyinsitureactionofSi3N4-ZrSiO4-Al2O3mixturewithfusedaluminaaggregates.Densification,insitureactionprocedureandmicrostructureofthematerialwereinvestigatedbymeansofX-raydiffraction,opticalandscanningelectronicmicroscopesandEDAX.
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.
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