DOC

Sn ternary systems by X-ray powder diffraction

By Bobby Reed,2014-02-18 21:34
8 views 0
Sn ternary systems by X-ray powder diffractionby,Sn,X,Xray,ray

    Sn ternary systems by X-ray powder

    diffraction

    RAREMETALS

    VoL29,No.6-Dec2oto,p.567

    DoI:10.1007/s12598010.01708

    Investigationonthe773KisothermalsectionofLaFe-Snternarysystemsby

    X-raypowderdiffraction

    CHENXiang,ZHUANGYinghong,andCHENYungui

    KeyLaboratoryofNonferrousMetalandNewProcessingTechnologyofMaterials(MinistryofEducation0,China),GuangxiUniversity,Nanning530004,China

    DepartmentofPhvsicsandElectronicInformationEngineering,NeijiangTeachersCollege,Neijiang641002China

    DepartmentofMetallicMaterialsEngineering,SichuanUniversity,Chengdu610065,China

    Received25August2009;receivedinrevisedform26December2009;accepted28December2010

    TheN0nfeITOUSMetalsSocietyofChinaandSpringer-VerlagBerlinHeidelberg2010 Abstract

    The773KisothermalsectionoftheLaFe

    SnternarysystemwasinvestigatedandconstructedbyX

    raypowderdiffraction(Xm3).Theex

    istenceoftworeportedternaryintermetalliccompounds,La6Fel3SnandLa3FeSn6,isconfirmedinthiswork.ComparedwithotherR-FeSn

    phasediagrams(R.PrandSm),thebinaryalloysFe3SnandFesSn3arenotpresent.ThecompoundFe3Sn2wasobservedfromthexRD

    paRemofFe3Sn2samples,butitisnotanequilibriumphaseat773KanddecomposesintoFeandFeSnphasescompletelyforalongerheat

treatedtime.Uptonow,thecrystalstructuredataofLa2Snhasnotbeenreposed,sotheX

    raypaRemofLa2Snwasonlyestimated.The

    phaserelationshipforthiscompoundwasdrawnbyadoRedline. Keywords:intermetallics;quenching;phasediagrams;Xraydiffraction

    1.Introduction

    Thephasediagramsofternarysystemsbasedoniron, rareearthfR)elementsandsemimetallicelementshavebeen studiedintensivelyasabasisofmagneticmaterialsresearch. IntheR.FeSntemarysystems.thephaseequilibriumhas alreadYbeenestablishedforR=Pr,Nd,Sm,Gd,andY [14].TheLaFe-Snsystemhasbeenpartlyconstructed[5]. La6Fei3Sn(La6ColiGa3type)andLa3FeSn6(CeNiSi2struc- turetype)havebeenreported[6].Inthispaper,theresultof X-rayinvestigationforthephaseequilibriuminthe LaFeSnternarysystemat773Kisreported.

    ThebinarysystemsinvolvedinthetemaryLaFeSn

    systemwerestudiedsufficiently.Nocompoundwasre

    portedintheLaFebinaryphasediagram[7].Sevenbinary compoundsLasSn3,LasSn4,Lal1Snlo,LaSn,La2Sn3,La3Sn5, andLaSn1werereportedintheLa.SnbinarysystemI81. TheFe.SnbinarysystemhasbeeninvestigatedinRef.1.3,

    9].Fourintermediatephases(FesSn3,Fe3Sn2,FeSn,and FeSn2)areshownintheFeSnbinaryphasediagram[1o],in

    whichthecompoundFeSndecomposestoFeandFe3Sn2 at1038K,andFeSn,decomposestoFeandFeSnat880K, respectively.ThestmcturaldatafortheintelTnetalliccom. poundsinthesethreebinarysystemsaregiveninTable1. Table1.CrystaldataofthebinarycompoundsinLa-SnandFeSnsystems

    Correspondingauthor:ZHUANGYinghongE-mail:gxucx@163.com 568

2.Experimental

    Lanthanum(99.9%purity),iron(99.9%purlty),andtin (99.999%purity,wereusedasthestartingmaterials.Al1 samples(230intota1),eachwithatotalweightofabout3g, werepreparedbyarcmeltingonawater-cooledcoppercru

    ciblewithnonconsumabletungstenelectrodeunderpure argonatmospherewithnormalpressure.Eachas.arccast

    buUonwasmeltedthreetimesandturnedoveraftermelting forabeRerhomogeneity.Weightlossesduringarcmelting werelessthan1%ofthetotalmass.therefore.nochemica1 analysiswascarriedout.

    A11samplesweresealedinanevacuatedquartztubefor homogenizationtreat.Thehomogenizationtemperatures werechosenbasedonthebinaryphasediagramsofthe La.Fe.LaSn.andFeSnsystems.andtheresultsofdiffer

    entialthermalanalysis(DTA)forsometypicalternaryal

    loys.ThealloyswithLaconcentrationsmallerthan80at% wereannealedatl073Kfor30d.whiletheothersamples wereannealedat973Kfor30d.A?thealloyswerecooled

    downatarateof10Kto773K.keptat773Kforl0d. andthenquenchedinto1iquidni~ogen.

    AllhomogenizedalloybuRonswereinvestigatedby X-raydiffractionanalysis(XRD),whichwascarriedouton aRigakuDMAX2500VdiffractometerwithCuradia

    tionandgraphitemonochromatoroperatedat40kVand200 mA.TheMaterialsDataInc.SoftwareJade5.0andaPow- derDiffractionFilefPDFrelease2002)wereusedtoana- 1yzetheXRDdataofallsamples.

    3.Resultsanddiscussion

    3.1.Binarysystem

3.1.1.La?Fesystem

    Thepresentworkindicatesthatnobinarycompoundex- istsintheLa-Fesystem,whichagreeswellwiththeresults reportedinRefs.7,1416].

    3.1.2.LaSnsystem

    SevencompoundslikeLasSn3,LasSn4,LaliSnlo,LaSn, La2Sn3,La3Sn5,andLaSn3werereportedintheLaSnbi

    narysystem[8.ThecrystalstructuredataofLasSn3,LasSn4, LaSn,La3Sns,andLaSn3weregiveninRef[11.Inthepre

    sentwork,itwashardtoobtaingoodX-raypatternsforthe sampleswithcompositionsbetween44.4at.%and62.5at.% SnintheLa-Snbinarysystemduetotheirhydrogenationor oxidationduringpreparing.BycarefullyanalyzingtheX-ray patternsoftheLaSnbinarycompoundsamples,wecon-

    firmedthatLasSn3,La5Sn4,LaSn,La3Sn5,andLaSn3existed intheLaSnsystemat773K,whichisinaccordancewith theresultsofRefs.[1719].FortheLaj,Sn,0sample,its

    XraypatternconsistsofLaSnandLasSn4phases,thus RAREMETALS,VoL29,No.6,Dec2010

    LauSnl0phaseshouldnotexistintheLaSnbinarysystem

    at773K.AsfortheLa2Sn3sample,wefoundthatthere weremanydiffractionpeakseXCeDtforthoseoftheproduct forthehydrolysis(freetinandamorphousoxidesorhy. droxidesofLaandSn).ThecrystalstructuredataofLa2Sn1

    raypaRernofLa2Sn3could havenotbeenreported,sotheX

    beestimated.Thephaserelationshipforthiscompoundwas drawnbyadotted1ine.

    3.1.3.Fe.Snsystem

    IntheFeSnbinaryphasediagram[10],therearefourin

    termediatephases(Fe5Sn3,Fe3Sn2,FeSn,andFeSn2).111e

    compoundFesSn3decomposesintoFeandFe3Sn2at1038K, andFeSn,decomposesintoFeandFeSnat880K,respec

    tively.Thus,onlyFeSnandFeSn2arestableat773K.Inour work,thephaseofFe5Snwasnotobserved,whichindicates thatFesSn3iscompletelydecomposed.Comparedwith FesSn3,thecompletedecompositionofFe3Sn2isdifficult, whichhasbeenprovedbytheXraypatternsofFe3Sn2(in-

    eludingthreephasesFe,Fe3Sn2,andFeSn).Inaddition,the XRDpattemsofothersamplesnearthethree-phaseregions alsoincludeFe3Sn2phaseexcepttheotherthreephases, whichisagainstthephaserule.Tofurtherapprovewhether Fe1Sn,existsat773K,somesampleswereannealedfor differenttimesofhomogenizationtreatandthen,theXRD patternsofthosesampleswerecompared.Fig.1istheXRD patternof#83samplewithacompositionof3.6at%La.28 at%Sn.and68.4at%FeafteronemonthandtworoODths annealing,respectively.ItisclearthatthecontentofFeSn andFephasesinthesampleafterlongtimeannealingis morethanthataftertheshorttimeannealing.butthevbOm containFe3Sn2phases.ThoseresultsindicatethatFe3Sn2 shouldnotbeanequilibriumphaseat773K.Fe3Sn2isob

    servedinourworkbecauseFe3Sn,doesnotdecomposeinto FeandFeSncompletely.anditneedsalongertimeforthe eutectoidreaction.Therefore,thereareonlytwobinary compoundsFeSnandFeSn,intheFe.Snbinarysystemat 773K.whichagreeswellwiththeresultofFeSnbinary

    phase131.

    3.2?Ternaryphases

    Twoternarycompounds,La6Fel3Sn(La6COl1Ga3-type)

andLa3FeSn6(CeNiSi2type)reportedinRef.[6,werecon

    famedinourwork.Inaddition,thecompoundRFe6Sn6,re

    portedinRefs.[3,2021],wasnotobservedinthiswork. TheXRDpatternoftheLaFe6Sn6sample(16),asshownin

    Fig.2,containsunequilibriumFe3Sn2phaseinadditionto threeequilibriumphases(LaSn3,FeSn,andFe3Sn2). 3.3.The773KisothermaiseetiOiloftheLa-FeSnter.

    narysystem

    Inthepresentwork,weusedXraypowderdiffraction

    ChenXeta1..Investigationonthe773KisothermalsectionofLa

    Fe-SnternarysystemsbyX-raypowderdiffraction569 (XRD)toanalyzeallsamples,andonlysomeXraypatterns

    ofimportantsamplesareprovidedinthispaper. Fig.3istheXRDpatternof#32sample(18at.%La,42 400

    200

    O

    at.%Sn.and40at.%Fe).Itisclearlyshownthatsample#32 consistsofLaSn3,La3FeSn6,andFephases. Fig.4istheXRDpattemof#42samplef12at.%La,74 ..h.^,.

    几…八'_.l1.I65.7253>F~Sn.Irofllin

    Ij060696>J1"011Fe

    I....Il30.0666>Fe3Sn2.IronTin

    II.656762>laSn3-LanthanumTin

    203O354O

    20/(.)

    Fig.1.XRDpatternsof#83sample(3.6aL%La,28at.%Sn,and68.4at.%Ve)afterdifferentti

    mesofheattreatment:.(a)one

    monthannealing;(b)twomonthsanneafing.

600

    500

    400

    300

    200

    lO0

    0……..?几人人….人一一ll654593>L~Sn3.LanthanumTin

    1.{f..f}f3O.0666>Fe3Sn2.JTOn1in I1I..165.3478>FeSn.1rollTin lJ060696>rod.Fc

    2O253O35

    1500

    000

    500

    O

    40

    20/(.)

    Fig.2.XRDpatternof#16sample(LaFe6Sn6). -

    

    _

    ..儿—一

    .

    一人

    IIl656762>LaSn3-LanthanumTin II.IIO00040>I/a3FeSI16-Powde~'elJ10 Il06.0696>Iron.Fe

    20253O3540

    20/(.)

    Fig.3.XRDpatternof#32sample(18at.%La,42at.%Sn,and40at.%Fe).

570

    750

    00

    50

    0

    RAREMETALS,Vo1.29,No.6.Dec2010

    .—九一….一『f656762>LaSn3_LanthanumTin

    1l652699>FeSn2IronIin

    i862264>finSn

    2O253035

    500

    400

    300

    200

    1()0

    O

    404550

    20/f.1

    Fig.4.XRDpatternof#42sample(12at.%La,74at.%Sn,and14at.%Fe).

    20253O404550

    20/(.)

    Fig.5.XRDpatternof#38sample(4at.%La,60at.%Sn,and36at.%Fe).

    at.%Sn,and14at.%Fe).ItconsistsofLaSn3,FeSn2,andSn phasesclearly.

    TheXRDpattemof#38sample(4at.%La,60at.%Sn, and36at.%Fe)iSshowninFig.5.anditconsistsofFeSn, LaSn3,andFeSn2phases.

    BasedonthephaseanalysisresultsofXRDpatternsfor al1samples.the773KisothermalsectionoftheLaFeSn

    ternarysystemwasdetermined.ThisiSOtherma1section.

showedinFig.6,consistsof12singlephaseregions,23

    two-phaseregions,and13three-phaseregions. ComparedwithotherRFeSnphasediagramsrRPr

    andSm)at773K[1,3],thebinaryalloysFe3SnandFesSn3 wereobservedinthisWOrk.Fe1Sn2hasbeenobservedinthe Fe3Sn2samplebutwasnotanequilibriumphaseat773K. ThereasoniSthatFe3Sn,needsquitealongtimeforits completedecompositionbytheeutectoidreactionmS.

    Fe3Sn2shouldnotexistat773Kunderequilibriumstate. OurresultoftheFe?-SnbinarysystemagreeswiththeFe-?Sn Sn

    Fig.6.The773KisothermalsectionoftheLa-Fe-Snternary system.

    (?henXeta1..Investigationonthe773KisothermalsectionofLaFe

    SnternarysystemsbyX-raypowderdiffraction57/ binaryphasediagram,andalsowiththeFeSnbinarysys

    ternintheGdFeSntemaryphasediagram4,13].Forter-

    narycompounds,R6Fel3SnandR3FeSn6(R=PrandSm), whicharereportedinRefs.[1,3],wereobservedinthis work.

    4.Conclusion

    The773KisothermalsectionoftheLaFeSnternary

    systemwasinvestigatedandconstructedbyX.raypowder difffaction(XRD).InFe.Snbinarycompounds,onlyFeSn andFeSn7aresteadyexistence.Althoughthecompound Fe3Sn2isobservedfromtheXRDpatternsofFe,Sn,sam. pies,itisnotanequilibriumphaseat773Kanddecomposes intoFeandFeSnphasescompletelywhenheattreatedfora longertime.SixLaSnbinarycompoundsareobserved.but theX-raypatternofLa2Sn1isonlyestimatedandthephase

    relationshipforthiscompoundisdrawnbyadottedline.For theLaFesnternarycompounds,La6Fe13SnandLa3FeSn6, areconfirmedinthiswork.Overal1.thisisothcrmalsection consistsof12singlephaseregions23two-phaseregions,

    and13threephaseregions.

    References

    [1]StepieflDammJ.,BodakO.I.,BelanB.D.,andGa|deckaE., ThePrFeSnternarysystem:phasediagramandcrystal stmcturcofPrFe045n2,AlloysCompd.,2000,298(12):

    169.

    2SalamakhaP.,DemchenkoP.,SologubO.,Bodak0.,and StepiefiDammJ..Interactionofneodymiumandironwimtin at500.Cand800.C,Poem.,1997,71f3):305.

    [3StepiefiDatumJ.,GaldeckaE.,Bodak0_I.,andBelanB.D., TheternarySmFeSnsystem:phasediagram.smJcturd1

    characterisationandmagneticpropertiesofternarycorn

    pounds,AlloysCompd.,2000,298(I2):26.

    4MudrykYa.,RomakaL.,StadnykYu.,Bodak0.,and FmchartD..XrayinvestigationoftheR.FeSnternarysys

    terns(RY,Gd),AlloysCompd.,2004,383(12):162.

    f51SkolozdraR.V.,Starmidesofrareearthandtransitionmetals, inGsctmeidnerK.A.Jr.andEyringL.,eds,Handbookon thePhysicsandChem~tryofRareEarths24.Elsevier.Am

    sterdam,1997:399.

    [6]6VillarsP.,PearsonHandbookofCrystallographicData, ASMInternaional,MaterialsPark,OH,1997:1757 f71MassalskiT.B.,OkamotoH..andSubramanianP.R.,Binary AlloyPhaseDiagramsTheMaterialsInformationSociety MaterialsPark.0H.1990:1718.

    f81PanY.Y.,NashP.,MassalskiT.B.,andSubramanianP.R.,

Report this document

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