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1、先进材料表征技术课程学生实验报告实验名称：姓 名：实验时间：年月日哈尔滨工业大学深圳研究生院I Purpose1. Be familiar with the scanning electron microscope structure and working principle;2. Be familiar with the requirements of sample preparation.II Equipment1. HitachiS-4700 SEM2. EDAX Energy Disperse SpectroscopyIII Principle1. SEMSEM body as sh
2、ow in Figure 1. Mainly include the main electron microscope electron optical system, the sample chamber, a detector, and a vacuum evacuation system power source circuit system.图 1 扫描电镜能谱仪Figure 2 shows the principle of SEM. An electron beam emitted from the electron gun , after the grid focusing eff
3、ect by acceleration voltage, electron- optical system through two or three electromagnetic lenses, and then electron beams will focus on the sample surface. Shooting a high energy electron beam to the sample material, we can get in a variety of information: secondary electrons, backscattered electro
4、ns, absorption of electrons, X-rays, Auger electrons, cathodefluorescent and transmission electronics.By analyzing these information we obtain the surface image of sample material.物镜试样电子枪第一聚光镜聚光镜:光阑第二聚光镜物镜光阖扫描线圏图 2 扫描电镜原理图2. EDSEDS mainly include the control and command system, X-ray signal detectio
5、n system, signal conversion and storage systems, data output and display systemcomponents.As shown in Figure 3 .液位传膳器I Sensiu电了捕集阱 HI it 1 rsn I nip准近器Col Iinutor Assenly场敗应秤FET薄窗W Indiiw图 3 能谱仪剖析图，晶体ClVhlH|When high energy electron beam interact with atoms on the surface of sample, inner, it may ma
6、ke atomic inner electron excited. And the inner vacancy occurs, the outer electrons transit to the inner vacancy and emit primary X-rays (eg L- shell electrons transit to the hole in K-shell formed Ka radiation). Primary X- rays relevant to atomic number. By counting the pulse obtained by Si detecto
7、r we can determine the elements.IV Results and analysisFigures 3 and 4 are SEM images of the specimen obtained by scanning electron microscopy. Figure 3 shows that the powder sample dispersed, and dont occur aggregation. The sample is being spherical, and has a preferred sphericity. The size is unif
8、orm and distribution between 30um 40um.Figure 4 show the sample enlarged 11,000 times in the electron microscope . From the image we can see the outer surface of ball is rough, and the sphere has a lamellar structure.图 3 试样 SEM (X2000)图 4 试样 SEM (xllOOO)Figure 5 is a sample spectrum of EDS , from th
9、e spectrum we can see three clear peaks, corresponding to the elements O, Mn, Co.Table 1 shows the content of elements obtained from the EDS spectrum.From the table,we know in percentage by mass O is 24.74%, Mn was 44.74%, Co 30.52%. Percentage atoms were 53.72%, 28.29%, 17.99%.表1试样元素含量对比ElementWt%A
10、t%OK24.7453.72MnK44.7428.29CoK30.5217.99MatrixCorrectionZAFV conclusionBy this experiment we know：1) SEM body mainly include the main electron microscope electron optical system, the sample chamber, a detector, and a vacuum evacuation system power source circuit system.2) SEM use the following signa
11、l for analyzing: secondary electrons, back scatting electrons and sometimes X-rays ,anger electrons. SEM mainly use secondary electrons, and the contrast depend on the curvature of the sample surface.3) We can gain these following information from SEM :topography and morphology ,Crystallography,Orientation of grains and Chemistry.4) EDS use X-rays for analyzing and distinguish element. EDS can obtain the quantities of given element but failed to distinguish isotopes.5) Sample of SEM must be conductive. If the sample is insulation , we must spray Au on the surface of the sample firstly.
