The Microstructure of SmCo5 Sintered Magnet Materials.

摘要

Using conventional (100 kV) and high (1 MV) voltage transmission electron microscopy, the microstructure of hyperstoichimetric SmCo5 magnet material has been examined. Second phase regions, investigated by electron-microscope microanalysis (EMMA), have been found to be either of composition close to Sm3Co or SmCo. Sm3Co is found both at grain boundaries and within the otherwise single-phase SmCo5 grains, whilst the SmCo regions are found only at grain boundaries. If the precipitation of Sm3Co near to grain boundaries in Sm-rich sinters is both typical of hyperstoichiometric magnets and a consequence of the ability of SmCo5 to exist over a range of compositions at elevated temperatures, then a new basis is provided for explaining some of the observed magnetic properties. (Author)