X-ray Powder DiffractometerPowderDiffractionof MaB,sample(101)MgB2(nesO)(200402(411)(100)(002502030407080602e(degrees)11
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第二章衍射分析之三、x射线衍射分析的应用第一节物相分析第二节点阵常数的精确计算第三节（选学）宏观应力的测量第四节（选学）晶体取向的测定12
12 第二章 衍射分析 之三、X射线衍射分析的应用 第一节 物相分析 第二节 点阵常数的精确计算 第三节 宏观应力的测量（选学） 第四节 晶体取向的测定（选学）
的应用X射线衍射(XRD)单一物相的鉴定物相定性分析物相分析混合物相的鉴定（物相鉴定）物相定量分析测定点阵常数（晶胞参数）的测定晶体对称性(空间群)晶体结构分析等效点系的测定晶体定向、非晶体结构分析、晶粒度测定、宏观应力分析13
13 单一物相的鉴定 物相定性分析 物相分析 混合物相的鉴定 （物相鉴定） 物相定量分析 点阵常数（晶胞参数）测定 晶体结构分析 晶体对称性（空间群）的测定 等效点系的测定 晶体定向、非晶体结构分析、晶粒度测定、 宏观应力分析 X射线衍射（XRD）的应用
The figure below compares the X-ray diffractionpatterns from 3 different forms of SiO,CountsSiO2Glass400020000Quartz40003000200010000Cristobalite40002000020403050Position[2Thetal (Copper(Cu)ThesethreephasesofSiO,arechemicallyidenticalQuartzandcristobalitehavetwodifferentcrystalstructuresTheSiandOatomsarearranged differentlybutbothhavestructureswithlong-rangeatomicorderThedifferenceintheircrystal structureisreflected intheirdifferentdiffractionpatternsTheamorphousglass doesnothavelong-rangeatomicorderandthereforeproducesonlybroadscatteringpeaks14
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Parallelplanesof atomsintersectingtheunitcell definedirectionsanddistancesinthecrystal.The(200)planesThe(220)planesofatomsinNaCiofatomsinNaciTheMillerindices (hkl)definethereciprocal oftheaxial interceptsThecrystallographicdirection,[hkll,isthevectornormalto (hkl)dhk is the vector extending from theorigin to the plane (hkl)and is normal to(hkl)The vector dhk, is used in Bragg's law to determine where diffraction peaks willbeobserveddnk is the vector drawn from the origin of the unit cell to intersect thecrystallographicplane(hkl)ata9oanglednk,thevectormagnitude,isthe distancebetween parallel planesofatoms inthefamily(hkl)15dnk is a geometric function of the size and shape of the unit cell
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