Anisotropic SmCo₅Nanocrystalline Magnet Prepared by Hot Deformation With Bulk Amorphous Precursors

摘要

Microstructure and magnetic properties of hot deformed SmCo₅nanocrystalline magnet prepared from amorphous precursors are investigated. Hot pressed magnet as a precursor of the hot deformed magnet is amorphous. After hot deformation process, the SmCo₅magnet with 85% height reduction exhibits CaCu₅crystal structures and the strong c-axis textures. Moreover, the hot deformed SmCo₅magnet bears magnetic properties of H_ci= 31.4 kOe, M_r= 6.42 kG, (BH)_max= 10.1 MGOe, and the remanence ratio of the magnet is as high as 0.87 due to the strong c-axis textures. In addition, fracture morphology shows that grains of the hot deformed magnet are plate shaped with an average grain size of 200 nm in thickness and 800 nm in diameter. Furthermore, the grain size of the magnet from transmission electron microscopy (TEM) observation has a good agreement with the scanning electron microscopy results. The TEM results also show that a lot of Sm-rich Sm-Co precipitate particles with a size less than 50 nm. These precipitate particles could act as pinning sites leading to high coercivity.