简介:Theswunggelfiberswereheatedto400℃at0.5,1,1.5,2,2.5,3and4℃·min-1ofheatingrate,respectively,andsoakedfor1h;thenheatedto600℃at3℃·min-1ofheatingrateandsoakedfor1h;atlastcalcinedat1000,1100,1200,1300,and1400℃for1h,respectively.Theaveragesinglefibertensilestrengthsoffibersaftercalciningat600℃orhighertemperaturesweredeterminedandtheirsurfacemorphologywasobserved.Theresultsshowthat:(1)whentheheatingratebelow400℃is0.5-1℃·min-1,theaveragesinglefibertensilestrengthsof95polycrystallinealuminafibersaftercalciningat600℃and1000-1100℃exceed1000and800MPa,respectively,surfaceofthefibersaftercalciningat1000-1100℃issmooth,α-Al2O3appearsat1200℃,andalargeamountofα-Al2O3formsabove1300℃;(2)whentheheatingrateexceeds3℃·min-1,thefiberspulverizeobviously.
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.