z值影响Sm(CoFeCuZr)_z磁性能的机理研究

The Sm(CoFeCuZr)_z permanent magnets with different z values (z=7.5~8.5) were prepared by powder metallurgy. The properties, constituent phase, precipitated-phase content, microstructure and element distribution of the magnet were characterized by magnetic measurement system, X-ray diffraction analysis, electron probe and transmission electron microscope. Magnetic properties changed with z value, and the inherent mechanism was explained. The results show that with the increase of z value the size of cell structure increases and the 2:17R phase with high saturation magnetization also increases in amount, which finally results in the improvement of remanence B_r. The precipitated Zr-riched phase increases when the z value increases, which has a weakening effect on the squareness H_k/H_cj. The z value changes the enrichment of Cu element at the edge of 2:17R phase, and thus influences the coercivity H_cj. Within the certain range (z <8.2), the higher the content of Cu at that edge, the larger the coercivity.