Multi-scale electron microscopy of overnitrided Sm-Fe-Mn-N powder

Abstract

Multi-scale electron microscopy technique that combines transmission electron microscopy (TEM) and focused ion beam - scanning electron microscopy (FIB-SEM) was utilized to investigate the influences of the change in microstructure of Sm2(Fe0.95Mn0.05)17Nx by overnitridation on the magnetic properties. The recent high-contrast backscatter electron imaging technique in SEM machines enabled us to reveal the formation events of cell-like microstructure from a quite large field of view. In addition, detailed TEM observations revealed the crystallographic orientations of the cells as well as the local chemical fluctuation. The combination of these techniques allows us to understand the microstructural hierarchy in this material, verifying that the original orientations of the individual particles are inherited to the nanocrystalline cells formed by overnitridation.