燃煤超细颗粒物的扫描电镜图像优化方法

SEM image optimization method of coal-fired ultrafine particles

燃煤超细颗粒物属于不导电粉体材料,拍摄过程中会产生不同程度的荷电现象,影响样品的形貌表征以及图像质量。为获得高质量的燃煤超细颗粒物的SEM图像,借助蔡司Sigma300场发射扫描电子显微镜,探讨探测器、加速电压、工作距离、光阑大小等对场发射扫描电子显微镜图像的影响。研究分析表明,InLens探测器适用于高倍成像及观察样品表面细节,但是不足之处是拍摄的图像立体感较差,容易受荷电效应影响;SE2探测器对样品表面形貌非常敏感,景深大,立体感强,特别适用于粗糙颗粒的观察研究;当燃煤超细颗粒物样品放电严重或者需要大景深、强立体感时可选用SE2探测器,工作距离WD=5 mm,电压3 kV左右,光阑30μm的参数条件下进行拍摄;当需要高倍成像及观察样品表面细节时可选用InLens探测器,工作距离WD=3.2 mm,电压2 kV,光阑30μm的参数条件下进行拍摄。

As non-conductive powder materials,coal-fired ultrafine particles will produce different degrees of charging phenomenon,which will affect the morphology characterization and image quality of samples.In order to obtain high-quality SEM images of coal-fired particles,Zeiss Sigma 300 field emission scanning electron microscope was used to investigate the effects of the detector,accelerating voltage,working distance and aperture size on FESEM image of coal-fired particles.The results show that InLens detector is suitable for high magnification imaging and observation of sample surface details,but the disadvantage is that the captured images have poor stereo perception and are easily affected by charging effects;SE2 detector is very sensitive to sample surface morphology,with large depth of field and strong stereo perception,Especially suitable for the observation and research of coarse particles;when the coal particulate matter discharge seriously,or a strong stereo feeling is required,SE2 detector should be chosen,with optimal working parameters(working distance:WD=5 mm,voltage:about 3 kV,aperture:30μm);InLens detector can be used when high-power imaging is needed and sample surface details are observed with optimal working parameters(working distance:WD=3.2 mm,voltage:2 kV,aperture:30μm).