SUN Qian¹,GAO Shang^2a,HUANG Mengshi^2a,MA Qing^2b,GUAN Kang¹,PENG Cheng¹

(1.School of Materials Science and Engineering,South China University of Technology,Guangzhou 510640,China;2a.School of Materials Science and Technology;2b.Education Center of Experiments and Innovations,Harbin Institute of Technology,Shenzhen 518055,China)

Abstract:In order to cope with the charge effect of nano-powders in scanning electron microscopy,the mechanism of charge effect was analyzed.The relationship between the sample and the incident electron beam response was derived to reveal the relationship between the accumulated effective charge density on the sample surface and the current,scanning time per frame,magnification and total electron production.After the charge field reached a steady state,the expression of the relationship between the accumulated surface potential and beam current,amplification,resistivity and total electron production was established.The advantages and disadvantages of various measures to alleviate or eliminate the charge effect were analyzed,the low voltage and high resolution imaging ability of modern field emission scanning electron microscopy was revealed and the optimal imaging strategy of field emission scanning electron microscopy was explored.The results show that the relationship expression can be used to guide the electron microscope parameter setting or detector selection to overcome the charge phenomenon.Plating conductive film on the surface of nano-powder can eliminate the charge effect,but it will affect the observation of the real morphology of nano-powder.Modern field emission scanning electron microscopy can realize low voltage and high resolution imaging,which can overcome the influence of coating on the morphology of powder.

Keywords:nano-powders;scanning electron microscopy;high resolution imaging;charge effect;low voltage

中图分类号：TG115.21⁺5.3;TQ577.7⁺7                  文献标志码：A

文章编号：1008-5548(2022)04-0070-09

DOI:10.13732/j.issn.1008-5548.2022.04.008

收稿日期： 2021-06-16， 修回日期：2021-12-21，在线出版时间：2022-06-17 11:33。

基金项目：国家自然科学基金项目，编号：51702100；教育部产学合作协同育人项目，编号：201802284007。

第一作者简介：孙千(1987—)，男，实验师，硕士，研究方向为陶瓷材料和材料表征。E-mail:mssqian@scut.edu.cn。

通信作者简介：高尚(1980—)，男，高级实验师，硕士，研究方向为材料表征。E-mail:gaoshang@hit.edu.cn。