透射电镜样品的制备：干粉法-液体.ppt

,透射电镜样品的制备：（1）分散晶体（粉末样）干粉法液体法（2）萃取复型：用于观察断口形貌，第二相大小分布，点阵类型（3）薄膜平面膜截面膜方法：超薄切片减薄人工+电化学减薄或离子减薄聚焦离子束,选区电子衍射：,阿贝衍射原理,倒易点阵与正点阵,d110,g110,b,a,r110,衍射几何条件：厄瓦球面,Thesizeofdiffractionpatterns,(1/l)/ghklL/RhklRd=lLWhenisqsmall(electrondiffraction),Rd=lL=diffractionconstant,q,Rhkl,Rhkl,Plottingandindexingofsinglecrystalspotpatterns,Whenqissmall(electrondiffraction),thereflectionspherecutsa2Dreciprocalplane.,S0/l=k0,S/l=k,ghkl,(hkl),000,相机长度,Rhkl,图3.9Al3Ni型正交相Al74.8Fe1.5Ni23.7的选区电子衍射花样,Plottingandindexingofsinglecrystalspotpatterns,Indexing:theplanenormaluvwandatleastonelowindexspot(hkl)(normallytwospots),withhu+kv+lw=0.,S0/l=k0,S/l=k,ghkl,(hkl),000,相机长度,Rhkl,Plottingandindexingofsinglecrystalspotpatterns,Foraknownsubstancebutunknownorientation,atableofinterplanarspacingsdisneeded.a)Choosethreespotssuchash3k3l3,h1k1l1,h2k2l2.b)Measurethedvalues,andthusdeterminetheindices.c)Bytrialanderroraconsistentsetofindicesischosensuchthath3k3l3=h1k1l1+h2k2l2.d)uvw,thezoneaxis,isobtainedbyanytwovectors(e.g.R1R2),S0/l=k0,S/l=k,ghkl,(hkl),000,相机长度,Rhkl,h1k1l1,h2k2l2,h3k3l3,uvw,R1,R2,Plottingandindexingofsinglecrystalspotpatterns,Example:anfcccrystalwitha=0.58nm.d=a/(h2+k2+l2)1/2.AdiffractionpatternisshownbelowwithR1=R2=8.96mm,R1R2=109.5.Ll=3.0nm.mm.a)ChoosethreespotsR1,R2,R3(R3=R1+R2)b)d1=d2=Ll/R1=0.335nm,111.c)Aconsistentsetofindicesis002=111+-1-11.d)R1R2=1-10,thezoneaxis晶带轴.,R1,R2,109.5,R3,也可以直接查表,PARAMETERSA=5.8000B=5.8000C=5.8000AF=90.000BT=90.000GM=90.000NUVW=3NSY=1NL=1SY:1-CUBIC;2-TETRA;3-ORTH;4-HEX;5-MONO;6-TRICLT:1-F;2-I;3-C;4-B;5-A;6-P;7-R;KUVWH1K1L1H2K2L2R2/R1R3/R1FAId1d2111102-2-2021.0001.000120.002.0512.0512110-11-1-1111.0001.15570.533.3493.34931000-2000-21.0001.41490.002.9002.90043322-2011-31.1731.54190.002.0511.74952212-2002-41.5811.581108.432.0511.29762111-1-102-21.6331.91590.003.3492.051731000-2-13-11.6581.65872.452.9001.74983110-222-4-21.7321.73273.222.0511.184932202-2-4242.1212.121103.632.051.967103312-2020-62.2362.23677.082.051.9171121000-2-2402.2362.44990.002.9001.297123211-1-1-13-32.5172.58297.613.3491.3311332000-2-4603.6063.74290.002.900.804,R2,R1,109.5,111,111,002,110,R3,220,Indexingofsinglecrystalspotpatternsfromanunknownphase,ProcedureSurveytheliteraturetocollectinformationofpossiblephases.ThreepossibleroutestoreachitsfullindexingCalculatedspacingsandcomparewithstandardpowderXRDdata;MeasureR2/R1,R2R1,andcomparewithtablesinarchives;Tryacubicphase;Usedoubletiltingtodeterminedirectlythe3Dreciprocallattice.Ingeneralthreeindependentpatternsarenecessarytodetermineareciprocalstructure.,R1,R2,109.5,R3,Adiffractionpatternisshownontheright:R1=R2=14.4mm,R1R2=109.5.Ll=3.0nm*mm.,StandardpowderXRDdata;,d1=d20.208d3=0.180d4=0.127,Cubicindexing,CubicindexingChoosethreeshortestreciprocalvectorsR1,R2,R3,R3=R1+R2,measuretheangleR1R2.Calculated1,d2,(R2/R1)2,(R3/R1)2.Judgepossiblecombinationsofhkl.Ingeneralthreeindependentpatternsarenecessarytodeterminethereciprocalstructure.,R1,R2,109.5,R3,Adiffractionpatternisshownontheright:R1=R2=14.4mm,R1R2=109.5.Ll=3.0nm*mm.,d1d2(R2/R1)2(R3/R1)20.2080.2081(1.155)2=4/3,Cubicindexing,R1,R2,109.5,R3,R1=R2=14.4mm,R1R2=109.5.Ll=3.0nm*mm.,d1d2(R2/R1)2(R3/R1)20.2080.2081(1.155)2=4/3=8/6111111111/111002/111,Cubicindexing,R1,R2,109.5,R3,R1=R2=14.4mm,R1R2=109.5.Ll=3.0nm*mm.,d1d2(R2/R1)2(R3/R1)20.2080.2081(1.155)2=4/3111-1-11-1-11/111002/111cF,a=0.36nm.奥氏体铁,Self-consistencyofindices:(111)+(-1-11)=(002)Anglecheck:(111)(-1-11)=109.5Latticeconstantcheck:a=d111*3=0.360nmTwomorepatternsarenecessarytoassurethephaseidentification,Exercises:indexthefollowingpatternsincubicschemes.Notethattheremaybemorethanonepossibilitiesforeachpatterns.Givethecorrespondinglatticetypesandconstants.,R1,R2,R3,R1=R2=R3=23.6mm,R1R2=120.Ll=3.0nm*mm.,d1d2(R2/R1)2(R3/R1)2latticeconstant0.1270.12711110-101-101/110011/110cP,cI0.18nm220-202-202/220022/220cF0.36nm,111,Exercises:indexthefollowingpatternsincubicschemes.Notethattheremaybemorethanonepossibilitiesforeachpatterns.Givethecorrespondinglatticetypesandconstants.,R1,R2,R3,R1=R2=16.7mm,R1R2=90.Ll=3.0nm*mm.,d1d2(R2/R1)2(R3/R1)2latticeconstant0.1800.18011100010010/100110/1000.180nm1-10110110/1-10200/1-100.255nm200020020/200220/2000.360nm,001,Exercises:indexthefollowingpatternsincubicschemes.Notethattheremaybemorethanonepossibilitiesforeachpatterns.Givethecorrespondinglatticetypesandconstant.,R1,R2,R3,R1=16.7mm,R2=R3=27.5mm,R1R2=107.5.Ll=3.0nm*mm.,d1d2(R2/R1)2(R3/R1)20.1800.10911/411/4002-31-1-31-1/002-311/002cF,0.36nm,130,Exercises:indexthefollowingpatternsincubicschemes.Notethattheremaybemorethanonepossibilitiesforeachpatterns.Givethecorrespondinglatticetypesandconstants.,R1,R2,R3,R1=16.7mm,R2=23.6mm,R1R2=90.Ll=3.0nm*mm.,d1d2(R2/R1)2(R3/R1)2a0.1800.12723001-110-110/001-111/001cP0.18nm1-10002002/1-101-12/1-10cI0.255nm002-220-220/002-222/002,110,Usedoubletiltingtodeterminedirectlya3Dreciprocallattice,000,000,a1,a2,a3,000,100,010,001,010,001,100,a1=26.56,120,110,210,120,001,a2=18.43,110,110,001,111,a3=18.43,010,000,001,100,101,Usedoubletiltingtodeterminedirectlya3Dreciprocallattice,图3.4六角相Al5FeNi的选区电子衍射花样Figure3.4SAEDpatternsarrangedinastereomannerofthehexagonalAl5FeNiphase.,Ringpatterns,Forrandomlyorientatedaggregatesofpolycrystals,thereciprocallatticebecomesaseriesofspheres.TheradiiRi=Ll/di.Thenumberofpointscontributingtoeachsphereisknownasthemultiplicity.,Ringpatterns,Ringpatterns,典型非晶电子衍射,Powderpatterns,图3.5铸态合金Al71Fe5Ni24的X射线(CuK=0.15406nm)衍射谱Figure3.5X-raydiffractionpatternoftheas-castAl71Fe5Ni24alloy.,Ringpatterns,HowtoindexaknownpowderpatternCalculatethedlistFindouttheindicesforeachpeakHowtoindexanunknownpowderpatternSurveytheliteratureCalculatethedlistComparewithXRDcards,