Microstructure Analysis of The Precipitation Hardened SmCo Permanent Magnet by Electron Microscopy

The microstructure of a precipitation hardened Sm (Co, Fe, Cu, Zr)_ permant magnet was investigated using electron microscopy. The Sm precipitates containig a very small amount of Co and Zr segregation were clearly revealed from scanning electron microscope images and EDX spectra. It was considered that the Sm precipitates were not combined fully with the matrix and were attributed to a brittle fracture. In addition to fine cellular microstructures consisting of the 2 : 17 phase, the 1 : 5 phase and the Z phase, detailed shapes and arrangements of the Sm precipitates were also clarified by transmission electron microscopy. Furthermore, a 180° magnetic domain wall was observed by Fresnel mode of Lorentz microscopy and the domain wall was found to be paralleled to the [1121]_ direction