XRD测定炭素材料的石墨化度

XRD,,(中南大学粉末冶金国家重点实验室,湖南长沙410083):研究了用X射线衍射(XRD)测定炭素材料石墨化度的原理和方法,指出其本质是精确测定炭石墨六方晶格的C轴点阵常数值,为此,用高纯硅粉作内标以校准测量误差.为提高测量精度,选用高角度的C(004)-Si(311)衍射线对;当试样的石墨化度较低时,因C(004)衍射线强度太小,选用C(002)-Si(331)线对.将它们分别进行KA1,KA2双线分离处理后,以KA1峰的半高宽之中心点定峰位并据此计算石墨化度.实验结果表明:在碳/碳复合材料中,由于采用了多种原材料,经高温热处理后形成石墨化的程度不尽相同,即试样中含有不同石墨化度的组分,致使炭石墨的衍射线呈现明显的不对称性,此时必须进行多重峰分离处理,分离出的子峰通常无需再进行双线分离,即可直接用来计算各组分的石墨化度;由各子峰的积分强度可计算不同石墨化度组分的相对含量,以此进行权重计算所得的平均石墨化度更合理地反映了试样内部石墨化度的实际情况.:XRD;石墨化度;多重峰分离;内标:O613.71:A:1005-9792(2001)03-0285-04,a=0.2461nm,c=0.6708nm,,,.,,/,,.,,.X,.,C/C.1(/)(),,.,.,,,.,.[1]:g=[(0.3440-c0/2)/0.0086]@100%.:g,%;c0c,nm.(1),c0=0.6708nm,g=100%;c0=0.6880nm,g=0%.2XQJ2507)93[2]XRD.(002),(004)d002d004(1),g.,.2.1,:2000-09-25:(1998[1817]):(1941-),,,,X.32320016J.CENT.SOUTHUNIV.TECHNOL.Vol.32No.3June2001[3],,Si,Si(2H).2.1.1标样制备和测量方法Si(w99.9%),01046mm,1100e/1h,.Si(5%,),,.(002)/(004),Si(111)/(311)2,1.g/%:1)9919;2)9011;3)5314;4)3917;5)3712;6)301511组试样的C(004)和Si(311)实测XRD曲线2.1.2KA1,KA2双线分离Si,Si(311).Si(a=0.543054nm)[4],CuKA1(KCuKa1=0.154050nm),BraggSi(111)Si(311)2(2HS)2HS(111)=28.443b,2HS(311)=56.128b.Si(111)Si(311)KA1,KA2,KA2KA1(2Hm)(2HS)$2HC(002)C(004),.2.2D/max)BKA1,KA2,3KA1():a12HH;b12HG;c12HT.,3.,,.,,,,,,C(004)Si(311)(1),,,.,,,.,,2HHd.2.311C(004)Si(311)XRD.,C(004),(2),(3,4,5,6)(1).,,[5-8].1.,,,(2).g/%:1)-716;2)5019;3)781023号试样C(004)衍射线经多重峰分离后的曲线3212863212种处理方法计算石墨化度g的结果g/%(KA1)gHgGgTg(KA)gP1w/%gP2w/%gP3w/%gP1100.199.6100.199.9-------290.689.190.690.1-------350.439.370.653.4-7.632.750.953.078.014.356.7440.127.951.239.7-75.613.58.236.456.150.131.1540.440.331.037.223.770.065.830.0--36.3632.926.432.130.5-51.121.925.861.671.616.527.7,1.1C(004)KA1,KA2.3,CuKA1gH,gG,gT,,g.1,ggH.23,4,56C(004),CuKA.(1),c0.3440nm.4a1c0.[7],.,C(004)C(002).,,,C(004),C(002).b1D/max-B,/,,,KA1,KAKCuKA=0.154178nm,KA1KCuKA1=0.154050nm.KA2.2,C(004)KKA2.,,,.2部分子峰经KA双线分离处理前后的石墨化度g/%)1)(KA),KA1,KA22)gHgGgTg3)P250.951.552.051.351.64)P356.157.056.556.256.65)P225.827.727.426.627.3:1)KA;2)KA1.5a1,Si,.b1,C(004),C(002).c1KA1,KA2,,,.d1(002)(004),.,.,.e1.:[1].[M].:,1997.[2]QJ2507-93,[S].[3].X[M].:,1987:200-205.[4].X()()[M].:,1986:386-388.[5].NKgk[J].2873,:XRD,1961,(64):1370-1375.[6],,.[J].,1986,(2):10-14.[7].[J].,1986,(5):10-14.[8].X[J].:,1990:148-150.GraphitizationmeasurementofcarbonmaterialbyX-raydiffractionQIANChong-liang,ZHOUGu-izhi,HUANGQ-izhong(TheStateKeyLaboratoryforPowderMetallurgy,CentralSouthUniversity,Changsha410083,China)Abstract:TheprincipleandmeasurementmethodforgraphitizationdegreeofcarbonmaterialsbyX-raydiffractionwereinvestigated,throughcalculatingthelatticeconstantcvalueofhexagonalsystemgraphiteprecisely.Soitwasveryneces-sarytocorrectmeasureerrorusinghigh-puresiliconpowderascalibratedstandardmaterial.Inordertoimprovemeasur-ingaccuracyandprecision,high-anglediffractionlinecoupleofC(002)-Si(311)shouldbeselected.Withregardtothema-terialoflowgraphitizationdegree,onlydiffractionlinecoupleofC(004)-Si(331)couldbeselectedbecausethediffractionintensityofC(004)wastoolow.ThroughseparatingthediffractionlinestotwopartsofKA1andKA2,graphitizationdegreewasobtainedbycalculatingthehal-fhigh-widecenterpointpositionofKA1peak.Thereexistdifferentgraphitizationde-greesinC/Ccomposite,andsotheprofileofdiffractionpatternwasnotsymmetrical.Somultiple-peakseparationshouldbeexecuted,andtheseparatedpeakscouldbeusedtocalculategraphitizationdegreedirectly.Inthiscondition,therecsnoneedforthedouble-peakseparation.Theintegralintensityobtainedfromeverysingle-peakcouldcalculatetherelatecontentofeverycomponent,anditwasveryreasonabletoinvestigatethetruegraphitizationdegreeofC/Ccomposite.Keywords:XRD;graphitizationdegree;multiple-peakseparation;inter-standard28832