以具有纳米孔道结构的不导电介孔氧化硅SBA-15为研究对象,系统研究了3种常见导电薄膜(金膜、铂膜和铬膜)对扫描电镜图像的影响.结果表明:在同样的镀膜条件下,蒸镀3种导电膜后扫描电镜图像的荷电现象均得到改善,但是镀金膜后无法观察到直径为4 nm的孔道,其完全被金颗粒所掩盖;蒸镀铂膜后,孔道形貌基本保持,但孔径显著降低;蒸镀铬膜后孔径和孔壁尺寸均与未镀膜前相差不大.导电薄膜中晶粒大小是决定薄膜对材料显微结构掩盖程度的关键因素,金颗粒大部分直径大于5 nm,铂颗粒大部分直径约为2 nm,因此蒸镀该两种薄膜均会导致SBA-15介孔材料4 nm的孔道不同程度地被掩盖;铬颗粒直径仅为1 nm,且主要以非晶状态存在,因此对介孔孔道的掩盖最少.

Taking non-conductive mesoporous SiO2 (SBA-15) with nano pore structure as the research material,the effects of three kinds of common electrical conductive coatings (Au,Pt and Cr coatings) on the field emission scanning electron microscopy (FE-SEM) images were studied.The results show that the charging phenomenon of the FE-SEM images could be reduced by all these three kinds of coatings.However,the morphology of the nano-size pores totally disappeared after coating Au film.When the Pt film was deposited on the sample surface,SBA-15 still kept the mesoporous structure but the pore size became smaller.Meanwhile,the pore and wall sizes of SBA-15 were close to the original morphology even though the Cr film was deposited on the sample.The grain sizes of the conducting coatings were the key factor of affecting the morphologies.The sizes of most of Au particles were over 5 nm,and sizes of most of Pt particles were about 2 nm.So the 4 nm pores of SBA-15 would be obscured by them.The sizes of Cr particles were only 1 nm and most of Cr particles were amorphous.Therefore,the real structure of SBA-15 could be shown even after the Cr film with several nano thickness was deposited.