DOC

Pore

By Gladys Torres,2014-02-18 11:39
9 views 0
Porepore,PORE,Pore,pores,pure,proe

    Pore

_China'sRefractories

    FangBinxiang,bornin1982inHunanProvince,isstudyingforhisPh.DinWuhanUniversityo

    f

    ScienceandTechnology.Hemainlyfocusesontheresearchofmicrostructurecharacteristics

    andtheircoIl'e.

    lationswithmechanicalandthermalpropertiesofcorundumbasedcastables.

    PoreSizeDistributionandItsQuantitativeRelationship withStrengthofCorundumBasedCastables

    FANGBinxiang,ZHUBoquan,LIXiangcheng,WANHongbo TheKeyStateLaboratoryBreedingBaseofRefractoriesandCeramics,WuhanUniversityof

    ScienceandTechnology,Wuhan430081,China

    Abstract

    Aseriesofcorundumbasedcastableswith0,2%,

    %,6%,and8%olAl20jmicropowderswereprepared

    usingtabularaluminaaggregatest63,3iand

    ?Jmm)attdfines(?D.088and?O.045am),cal

    ciumaluminatecement,andf20jmicropowders(d =.754tzm1asstartingmaterials.Coldmechanical strengthandporesizedistributionofthecastables@eci

    meltsafterheattreatmentat110.100and500?

    weretested,respectively.Thequantitativerelationship betweenstrengthandapparentporosity,andthatbe

    tweenstrengthandmedianporediameterwereverifiedby Atzeniequation.Thecorrelationbetweenintervalofpore seattdmechanicalstrengthofspecimenswasalsostud

    ledbymeansofgrayrelationaltheory.Theresultsshow that:()theporesizedistributionofcastablesisstrong

    lyinfluencedbybothmicropowdersfillingandmatrix sintering;theadditionofmicropowdersdecreasesmedian porediameterwhilethesinteringprocessincreasesit; (2)whenaddingaconstantcorrectionterm,Atzeni equationcan,substantiallydescribethequantitativerela

    tionshipbetweenmedianporediameterandstrengthof

     castablesspecimenserheattreatmen.tatthesam.etern

    perature;thesignificantdifferencesofthegrayrelational betweentheintervalof

    strengtharecharacterized;itis

    san'beintervalofporesize,

    16China'sReflactoiiesVol

    poresizeandcastables

    alsofoundthatforthe

    thegrayrelationaldegreeis

    19.NO4,2010

    affectedbytheheattreatment

    interval<0.5mhasthe

    temperature;theporesize

    highestgrayrelationaldegree

    withthestrengthat110500?.

    Keywords:Castables,Poresizedistribution, Strength,Atzeniequation,Grayrelationaldegree Strengthofrefractorycastables,mainlydecidedby chemicalmineralcomposition,structure,andmanu[ac

    turingtechnique,isoneofthekeyparameterstojudge thepropertiesofrefractorycastables?-sj.

    However,for

alongtime,theeffectsofporosityandporesizedistri

    bution,etc.onstrengthofrefractorycastablesareneg

    lected.Itisnotablethatinthebuildingconcretemate

    rialssystemsimilarwithrefractorycastables,there

    searchofporestructureparametereffectonproperties developsgreatly,whichincludesthefamousAtzeni equationreflectingrelationshipsofconcretestrength, porosity,andmedianporediameter_4-s3.

    Grayrelationanalysisisakindof"datalacking resultsuncertainty"factoranalysismethod[.Theaim

    ofgrayrelationanalysisistoresearchthemainrelation

    shipsamongfactorsinasystem,andthentofindout themaininfluencefactorofthesystem.

    Porestructureparameterssuchasapparentporosi

    tyandporesizedistributionhaveuncertainrelationship withstrengthofrefractorycastables.Inthiswork, effectsofoLA1,0mieropowderadditionandheattreat. PoreSizeDistfibution

    menttemperatureonporesizedistributionofrefractory castableswereresearchedusinglowcementcorundum basedcastables,andtherelationshipbetweenporesize distributionandstrengthofthecastableswasalso researchedusingAtzeniequationtofindthegeneral T1les

    Thetabularcorundumgrainsandfines(w(A1203) >99.5%),Secar71calciumaluminatecementand active-A1203micropowder(w(A12O3)>99.5%) fromALMATISwereusedasstartingmaterials,andpo

    lyethyleneglycol(FS10)asdispersant.Thepanicle

sizeofactiveotA12O3micropowderwasdetermined

    usingMASTERSIZER2000laserpanicleanalyzer,and theaverageparticlesizewas1.754Ixm.Thepanicle sizedistributionisshowninFig.1.

    Fig.1ParticlesizedistributioncurveofactiveteAl2O3 micropowder

    ThematerialswereweighedaccordingtoTable1, evenlymixed,addedwithwaterandstirred,thenvi. bratoryshapedintospecimens.Aftercuringandde

    moulding,theapparentporosity,coldcrushingstrength, andcoldmodulusofruptureofthespecimenstreatedat 1l0?f0r24h.1100?for3h.and1500?for

    3h,respectively,weredeterminedaccordingto GB/T2997.2000andYB/T520l1993:theporesize

    distributionwasdeterminedusingmercuryinjectionap

    paratus(IV9510,MikeCo.,Ltd.,USA)accordingto YB/T1l8.1997:thequantitativerelationshipbetween poresizestructureparameterandcastablesstrengthwas alsoresearchedusingAtzenjequation.

    2.1InfluenceFactorsofPoreSizeDistributic markedandthevalueisthedifferentialinvasionlog

    arithm.Thebiggerthevalueis,thehigherthefrequen- cyoftheporesizeis.Themedianporediametercurves areshowninFig.3.

    Table1Formulationsofcastables/wt%

    Tabularcorundumor..A1,0

    No.63,31,?0.088andmicropowderCement

    ?1illm?0.045ram)(=1.754Ixm)

    A

    B

C

    D

    E

    O

    2

    4

    6

    8

    4%

    001O1

    Particlesize//am

    (a)l10?

    100

    4%

    001011lO

    Paniclesize/um fb)l1O0?

    oo

    O00l11O

    Paniclesize/um (c)1500oC O0

    4

    4

    4

    4

    4

    Poresizedistributioncurvesofspecimenswithdif-Fig.2Poresizedistributioncurvesofspeci

    menswithdiffer.

    ferent

?A1203additionsfiredatdifferenttemperaturesentcx-AI203micropowderadditionsfire

    datdifferent

    areshowninFig.2.Longitudinalcoordinateisnottemperatures China'sRefractoriesVo[19,No4,201017

    ?

    醯醯矾

    0磬兰2Q暑一r

    FANGBinxiang,ZHUBoquan,LIXiangcheng,otal w(dAI2O

    w(d.AIO,u/0

    Fig.3Influencesofot-Al2O3micropowderadditionsonme? dianporediameterandapparentporosityofspeci- mensfiredatdifferenttemperatures

    AsshowninFig.2,almostalltheporesize

    curveshavetheonlystrongpeak,whichmeansthe poresizeconcentratesinanarrowrange.Asof.A1203

    micropowderadditionincreases,thepeaksoftheCurves movetowardsthesmallporesizedirectionandtheme

    dianporediameterdecreasesdramatically.Thismeans thato【一A1203micropowderhelpstofillthegapsbetween aggregateandmatrix,makingthegapssmalloreven disappear.Ontheotherhand,asthetiringtemperature rises,theporesizecorrespondingtothepeaksincrea

    ses,andthemedianporediameterincreases. ItisalsofoundinFig.3thatthemedianporedi

    ameterandtheapparentporositychangewithtempera

    tureand仅一A12O3micropowderadditioninthesimilar way.Comparedwiththespecimenfiredat110?.the

    specimenfiredat1100?hasasimilarmedianpore

    diameterbutamuchlargerapparentporosity.Itmeans

    at1100oC,cementhydratedehydratesformingpores, makingtheporesizeparametersimilartothatofthe specimentiredat110oC.Whenthefiringtemperature risesto1500oC,themedianporediameterincreases obviouslyandtheapparentporosityrisesaswel1.This mayberelatedtothereactionandsinteringinsidethe system:ononehand,thesinteringdensitiesthema. trix,makingthemicroporesdisappearandincreasing themedianporediametersignificantly;ontheother hand,astheformationoftheCA6phaseinthematrix, volumeofthespecimenexpands,increasingtheappar

    18chff1.'sR.fracc.fsVol19No4.2010

    entporosityfurther.

    2.2QuantitativeRelationshipSetlNeenPoreStruc- Thestrengthofthecastablesfiredatdifferenttern

    peraturesisshowninTable2.Itisfoundthatboththe additionofOLA12O3micropowderandtiringtemperature "affectthestrengthobviously.Fromtheinfluencefactors ofporestructureparameterdiscussedabove,boththe strengthandtheporestructureparametervarywiththe ot-A12O3micropowderadditionandthefiringtempera

    ture;andtheymustbeinfunctionrelationship.Sofar, thereisnopremserelationshipexpressmnamong castablesstrength,apparentporosity,andporesize distribution.Thus,theAtzeniequationwidelyapplied inthebuildingconcretefieldwasstudiedtoverifythe feasibilityinrefractorycastablessystem. Table2Mechanicalstrengthofspecimensfiredatdifferent temperature

黪露hIenNABcD嚣誓

    Crashing110?72.869096.64109l17

    strength1100oC41.8245.4153.3359.7870.67 /MPa1500?84.48118.52164.53174.04218.26

    Modulus1l0oC6.8911.2514.8918.4315.91

    ofrupture1100?5.326.378.569.08l1.7

    /MPa1500oC22.6429.3137.2744.9544.95

    AtzeniequationwasputforwardbyC.Atzeni,L. Massidda.andU.Sannaasfollowsi.1..t23: or=K(1P)r(1)

    where,or,P,andrarethestrength,theapparentpo

    rosity,andthemedianporediameterofconcrete,re

    spectively,andKisacorrelativeconstantofthecon. cretesystem.

    Thestrength,apparentporosity,andmedianpore diameterofthecastablesspecimensfiredatdifferent temperatureshavebeendetermined,so(1P)rmis

    plottedfordifferentor.Ifitisastraightlinethroughthe originofthereferenceflame,itshowstherelationship betweenstrengthofcorundumbasedcastablesandpore structureparameteraccordswithAtzeniequation.The fittedlinesoforand(1一尸)rmfordifferentspeci

    mensareshowninFig.4,where,abscissaandordi

    natestandfor(1P)rmandor,respectively,Risa

    correlativecoemcient.

    Figure4showsthefittinglinesofcrushingstrength ormodulusofruptureto(1P)rfiredat110,

    1100,and1500oCarestraight,butdon'tpass throughtheoriginofthereferenceframe.Kvaluesof crushingstrengthare40.76,34.41,and315.01

n/-IuIBIqo(一盘口苫\0J0lu厶《

    PoreSizeDistributionandItsQuantitativeRelalionshipwithStrengthofCorundumBasedC

    a——

    stable

    s

    

    MPa?mn,respectively,andKvaluesofmodulusof ruptureare9.10,1.10,and83.42MPa?n10,re

    spectively.So,Atzeniequationneedstobecorrected, andwhenaconstantisaddedtotherightsideofthe equation,themodifiedequationcanexpressthequanti

    tativerelationshipbetweenthestrengthandthepore structureparameterofcorundumbasedcastables.Itis alsoobservedtherelativityofthefittedlinesofcrushing strengthormodulusofruptureto(1P)rofspeci

    mensfiredat1100and1500oCishigherthanthatof thespecimenfiredat110oC,whichshowsAtzeni equationismoresuitableforcastablessystemfiredat hightemperatures.

    2.:2,0:;r,.,i.j0j,?jz:0.:

    :):0j000i

    Inordertofindouttheeffectofporesizeinterval atdifferentrangesonstrengthofcastables,thepore sizeofcastablesspecimenswasclassifiedinto6inter-

    0.5,0.51,13,3 vals,namely,<0.2,0.2

    9,>9Ixm,andtherelationaldegreebetweenpore sizeintervalandstrengthofcastableswasresearchedby grayrelationanalysistheory.Thecrushingstrengthand modulusofruptureofcastablesspecimensfiredat differenttemperaturesareusedasmainseries,andthe

volumepercentageofrelativeintervalofporesizeis

    usedassub?series,therelationaldegreebetweenpore

    sizeintervalandcrushingstrengthormodulusofrup tureiscalculated(thedistinguishingcoefficientis0.5,

    andthecalculationreferstoReference[8]),andthe

    resultsareshowninTable3. .

    

    

    

    U

    

    0

    

    

    40L

    04

    ?1l0?

    ?1100?争

    ..?

    /y=0IX(R2=0963)-7683+3150963/y=

    06081.012l4l618

    (1P)/v~7

    (a)

    ?ll0?^,

    ?1100?/

    01500?/

    ,

    

Report this document

For any questions or suggestions please email
cust-service@docsford.com