Hello Ahmed,

My experience is analyzing micron diamond powders in ranges of 2-4mic. 4-6mic. up to larger sizes of 50 & 70mic. The most used method is using a conductive adhesive tape witch is a must in and SEM system. It can be a carbon mounting tape, a copper mounting tape and others. A small amount of the powder can be spread on one side of the dual sided tape. A good source can be found in the bellow site: https://www.tedpella.com/semmisc_html/semadhes.aspx

doing this process with Nano powders may be tricky to handle but can be developed. I hope this is of help.

Gideon Levinson

One more comment to consider:

A thin gold coating (a few angstroms) on the powders by spattering may be required in the SEM system in order to have a better electrical conductivity.