Scanning electron microscope and metallographic microscope belong to optical instruments. Many people prefer to use metallographic microscopes as scanning electron microscopes, but there is a big difference between them, and the wrong use can only put more burden on the equipment and accelerate the consumption of metallographic microscopes.

The difference between a scanning electron microscope and a metallographic microscope

First, the principle is different: metallographic microscopy uses geometric optical imaging, while scanning electron microscopy uses various physical signals excited by a fine-focused electron beam scanning the surface of a sample to modulate the image. The sample surface is bombarded with a high-energy electron beam, and various physical signals are excited on the sample surface, which is received by different signal detectors and converted into image information.

First, the principle is different: metallographic microscopy uses geometric optical imaging, while scanning electron microscopy uses various physical signals excited by a fine-focused electron beam scanning the surface of a sample to modulate the image. The sample surface is bombarded with a high-energy electron beam, and various physical signals are excited on the sample surface, which is received by different signal detectors and converted into image information.

Secondly, the light source is different: a metallographic microscope uses visible light as the light source for the image while a scanning electron microscope uses an electron beam as the light source for the image.

Different resolution: the resolution of the metallographic microscope is limited to 0.2-0.5um due to the interference and diffraction of visible light. The scanning electron microscope uses an electron beam as the light source, and its resolution can reach between 1 and 3nm. Therefore, the microstructure observation of metallographic microscope belongs to micron level analysis, while that of scanning electron microscope belongs to nanometer level analysis, and the sample information obtained by scanning electron microscope is more abundant.

Different resolution: the resolution of the metallographic microscope is limited to 0.2-0.5um due to the interference and diffraction of visible light. The scanning electron microscope uses an electron beam as the light source, and its resolution can reach between 1 and 3nm. Therefore, the microstructure observation of metallographic microscope belongs to micron level analysis, while that of scanning electron microscope belongs to nanometer level analysis, and the sample information obtained by scanning electron microscope is more abundant.

Different depth of field: Generally, the depth of field of the metallographic microscope is between 2-3um, so the sample surface smoothness has a very high requirement, so the sample preparation process is relatively complicated. The depth of field of a scanning electron microscope is hundreds of times that of the metallographic microscope, but due to the limitation of its imaging principle, the sample surface must be conductive, so the sample surface must be conductive processing.

Different depth of field: Generally, the depth of field of the metallographic microscope is between 2-3um, so the sample surface smoothness has a very high requirement, so the sample preparation process is relatively complicated. The depth of field of a scanning electron microscope is hundreds of times that of the metallographic microscope, but due to the limitation of its imaging principle, the sample surface must be conductive, so the sample surface must be conductive processing.

Compared with a metallographic microscope, a scanning electron microscope has wide adjustable magnification, high resolution of the image, large depth of field, rich three-dimensional image, more abundant sample information, and more in-depth and extensive application than a metallographic microscope.