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  • Scanning Electron Microscope (SEM)

    Scanning electron microscope (SEM) is an advanced micro-area morphology analysis instrument, which makes a qualitative leap in human ability to observe the micro-world. Relying on the advantages of high resolution, large depth of field and wide range of magnification, scanning electron microscope is widely used in micro-analysis and element composition analysis of various materials, and has become an indispensable tool for micro-detection and research.

    Scanning Electron Microscope (SEM)

    SEM principle

    The basic principle of scanning electron microscope is that the electron beam emitted by the electron gun is used to scan the sample surface like a raster after focusing, and the surface morphology, composition and structure are observed and analyzed by detecting the signal produced by the interaction between the incident electron and the sample. Among the excited signals, secondary electrons are mainly used for surface morphology observation, backscattered electrons, characteristic X-rays and Auger electrons are mainly used for composition analysis, and scanning electron microscopy uses a variety of signals to comprehensively analyze material samples.

    Scanning Electron Microscope (SEM)The signals generated by electron beam interaction with sample

    What is the main testings of SEM?

    Scanning electron microscope is mainly used to observe and analyze the morphology/size of materials, analyze the material film with coating, perform EDS element analysis on the material micro-area, cell observation, and perform element determination during the failure analysis of the material, metallographic analysis, etc. It is widely used in materials, chemistry, biology, medicine, geology and other fields.

    The SEM test items of T,C&A Lab include:

    Scanning Electron Microscope (SEM)

    • Automated SEM particle analysis
    • Particle size distribution determination
    • Fractured surface analysis
    • Polymer cross-section analysis
    • Contamination analysis
    • Examination of pharmaceutical ingredients
    • SEM/EDS elemental mapping
    • Particle and surface morphology studies
    • Material characterization
    • High resolution SEM imaging

    Technical parameters

    • Secondary electron resolution: 1.4 nm (1 kV, deceleration mode)
    • Magnification: ×20~×800,000
    • Electron gun: cold field emission electron source

    Sample delivery requirements and precautions

    • Between 50-100 mg for powdered samples
    • The bulk sample cannot be larger than the width of 5 mm and the height is less than 5 mm
    • Please let us know if the sample is magnetic

    Sample preparation

    • Metal coating method
    • The application object is the sample with poor conductivity, such as polymer material. Before scanning electron microscope observation, a layer of conductor must be evaporated on the sample surface, in order to eliminate the charging phenomenon, improve the excitation amount of secondary electrons on the sample surface, and reduce the radiation damage of the sample.

    • Ion etching method
    • The application object is the sample which consists of crystalline phase and amorphous phase. When the sample surface is bombarded by ions, the fine structure of the crystal region is exposed because the two phases are affected by different ions.

    • Chemical etching
    • The application object is the same as ion etching, including solvent etching and acid etching.

      Acid etching is the use of some oxidizing solutions, such as fuming nitric acid, potassium permanganate and so on, to treat the surface of the sample to make one of the phases oxidize and break the chain and dissolve, thus exposing the structure of the crystal phase.

      Solvent etching is the selective dissolution of one phase of a polymer material with some solvents, thus exposing the structure of another phase.


    1. Sun, W.; et al. Effects of carbon content on the electrochemical performances of MoS2–C nanocomposites for Li-ion batteries. ACS applied materials & interfaces 8.34 (2016): 22168-22174.
    2. Spiegelberg, et al. Characterization of physical, chemical, and mechanical properties of UHMWPE. UHMWPE Biomaterials Handbook. William Andrew Publishing, 2016. 531-552.

    Note: this service is for Research Use Only and Not intended for clinical use.

    T,C & A LAB is an independent lab providing quality or custom testing, characterization and analysis of a variety of materials. Our engaged experts are ready to help you.

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