z值影响Sm(CoFeCuZr)z磁性能的机理研究

Mechanism research of z Value Affecting Magnetic Properties of Sm(CoFeCuZr)z

摘要:

通过粉末冶金法制备了不同z值(z=7.5~8.5)的Sm(CoFeCuZr)_z磁体。利用磁性能测量系统、x射线衍射分析、电子探针以及透射显微镜等对磁体的性能、组成相、析出相含量、微观结构及元素分布进行表征,通过分析解释了磁性能随z值变化的内在机理。结果表明：随z值增大,胞状结构尺寸增大,高饱和磁化强度的2:17R相增多导致剩磁B_r升高；z值增大导致富Zr析出相增多,引起方形度H_k/H_cj下降；z值通过改变Cu元素在2:17R相界面位置的富集程度来改变矫顽力H_cj的大小,在一定范围内(z<8.2)该位置Cu含量越高,矫顽力越大。

关键词:Sm(CoFeCuZr)_z磁体;z值;磁性能;微观结构;Cu元素分布

Abstract:

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 change with z value, and the inherent mechanism is explained in this essay. The results show that the increase of z value leads to the increase in the size of cell structure and the 2:17R phase with high saturation magnetization, which finally results in the improvement of remanence B_r. The precipitated Zr-riched phase increases with 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, which has a significant effect to the coercivity H_cj. Within the certain range (z <8.2), the higher the content of Cu at that edge, the larger the coercivity is.

Key words:Sm(CoFeCuZr)_z; z value; magnetic property; microstructure; distribution of Cu element