SEM实验报告(英文)

《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 Purpose

1. Be familiar with the scanning electron microscope structure and working principle;

2. Be familiar with the requirements of sample preparation.

II Equipment

1. HitachiS-4700 SEM

2. EDAX Energy Disperse Spectroscopy

III Principle

1. SEM

SEM body as show 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 effect 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 electrons, absorption of electrons, X-rays, Auger electrons, cathode

obtain the surface image of sample material.

图2 扫描电镜原理图

2.EDS

EDS mainly include the control and command system, X-ray signal detection system, signal conversion and storage systems, data output and display system components.As shown in Figure 3 .

图3 能谱仪剖析图

When high energy electron beam interact with atoms on the surface of sample, inner, it may make 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 Kα radiation). Primary X-

rays relevant to atomic number. By counting the pulse obtained by Si detector

we can determine the elements.

IV Results and analysis

Figures 3 and 4 are SEM images of the specimen obtained by scanning electron microscopy. Figure 3 shows that the powder sample dispersed, and don’t occur aggregation. The sample is being spherical, and has a preferred sphericity.

The size is uniform 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 (× 2000)

图4 试样SEM （×11000）

Figure 5 is a sample spectrum of EDS , from the spectrum we can see three clear peaks, corresponding to the elements O, Mn, Co.

图5 EDS 图谱

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

V conclusion

By 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 signal 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.