材科-chap7電子衍射7.8電子顯微鏡中

第七章電子衍射第七節(jié)品厚度t 滿足布拉格衍射條件當賦予倒易點以衍射屬性時，倒易，并且當?shù)挂c偏離反射球為s時，仍會 設晶體在x,y,z方向的邊長分別為t1t2t3s=0,強度最大；s=±1/t,強度為0.oc

b

2G(si2si2或G(si21s22ti

盤

111t D

1 1 11

偏離矢量

電子 時會轉(zhuǎn)過一定的角度，這個角度就是磁轉(zhuǎn)角φ。雙 法攝晶體和衍射花 圖7-13磁轉(zhuǎn)角的標定

單晶根據(jù)hkl};測定各衍射斑點之間的夾角IndexingdiffractionThefundamentalrelationshipindiffractionpatternMeasureR1,R2,andMeasureR1,R2,andCalculateCalculated1andCheckCheckd1,d2and dataofcertainUsevectoraddition,togettherestindices(h3=h1+h2,k3=k1Usevectoraddition,togettherestindicesCameraconstant(performedonJOELCompactCompactBioglass?RSBFGold(111)Themeasuredvalueis2.30?,whileitrealvalueis2.35?Actualcameraconstantshouldmultiply2.35/2.30立方晶體中同一面族中各晶面的間距相等。令h2k2l2=值作為 面族的整數(shù)指數(shù) d

h2k2l

R2R2:R2:R2:N:N:N: 查卡片，和各。 第十節(jié)多晶體的電子衍射花樣晶面間距相同的{hkl}面族中基本符合布拉格條件的晶面所產(chǎn)生的衍射束會構(gòu)成以入射束為軸、θ±ΔθAmorphoustricalciumAmorphoustricalciumPrecipitateonstainlessPrecipitateonstainless500100Precipitateonstainless200

IobservedthatOCPwasformedinTEM!!!圖7-18多晶體環(huán)根據(jù)值求出相應的值;

圖7-19相機常數(shù)λL已知把（d,I/I1)列表；Ca10(PO4)6(OH

_P a=19.692b 9.523c 6.835

90.15 92.54=108.65Ca8(HPO4)2(PO4)4P63 a=9.432c=6.881Hydrated ApatiticTworelatedsetsofspotASomerowsofspotsindicatedbyredcirclesgraduallydisappear.AHA,

IsOCP[210]HABHAorjustlostHA,Underelectronbeam,OCPchangesinofmorphology,spotpatternandlatticeOCP9.384(1-89.68OCP4.6918(2-89.68OCP4.7454(1-89.63HA[1-90Threesimulatedspot

1

OCP,B=

OCP,B=

HA,B=OCP89.6889.