GB/T 18907-2013 in English

《GB/T 18907-2013微束分析 分析电子显微术 透射电镜选区电子衍射分析方法》由TC38（全国微束分析标准化技术委员会）归口，主管部门为国家标准化管理委员会。
本标准规定了用透射电子显微镜(TEM)对薄晶体试样的微米和亚微米尺寸区域进行选区电子衍射分析的方法。被测试样可以从各种金属或非金属材料的薄切片获得,也可以采用细微的粉末或萃取复型试样。应用本方法可分析的最小试样选区直径取决于显微镜物镜的球差系数,对于现代TEM,试样的最小选区直径一般可达到0.5μm。
当被分析试样区的直径小于0.5μm 时仍然可以参照本标准的分析方法,但是由于球差的影响,衍
射谱上的部分信息有可能来源于由选区光阑限定的区域之外,在这种情况下,如条件允许,最好采用微
(纳)衍射或者会聚束电子衍射方法。
选区电子衍射方法的成功应用取决于对所获得的衍射谱指数标定正确与否,而不论试样的哪个晶带轴平行于入射电子束,因而,这样的分析往往需要借助试样的倾转和旋转装置。
本标准适用于从晶体试样上获取SAED 谱、标定衍射谱的指数以及校准电镜的衍射常数。

Scope

This standard specifies the method for the selected area electron diffraction analysis of micron and submicron sized regions of thin crystal samples by transmission electron microscopy (TEM). The samples to be tested can be obtained from thin slices of various metal or non-metallic materials, and fine powder or extracted replica samples can also be used. The minimum diameter of the selected area of the sample that can be analyzed by this method depends on the spherical aberration coefficient of the microscope objective lens. For modern TEM, the minimum diameter of the selected area of the sample can generally reach 0.5 μm. When the diameter of the sample area to be analyzed is less than 0.5 μm, the analysis method of this standard can still be referred to, but due to the influence of spherical aberration, part of the information on the diffraction spectrum may come from outside the area limited by the selected aperture. In this case, if conditions permit, it is best to use micro (nano) diffraction or convergent beam electron diffraction. The successful application of the selected area electron diffraction method depends on the correct calibration of the obtained diffraction spectrum index, regardless of which crystal zone axis of the sample is parallel to the incident electron beam. Therefore, such analysis often requires the use of sample tilt and rotating device. This standard is applicable to obtain the SAED spectrum from the crystal sample, calibrate the index of the diffraction spectrum and calibrate the diffraction constant of the electron microscope.