Preparation of anisotropic Sm2Fe17N3 magnetic powders with enhanced coercivity by high-energy ball milling
LI Wei1,2, GUO Jiarui1,2, ZUO Siyuan1,2, WANG Yana1,2, HUANG Guangwei1,2, ZHENG Liyun1,2
1. School of Materials Science and Engineering, Hebei University of Engineering, Handan 056038, China; 2. Hebei Engineering Research Centre for Rare Earth Permanent Magnetic Materials & Applications, Handan, 056038, China
Abstract：Sm2Fe17N3 magnetic powders were prepared by high-energy ball milling. The effects of ball milling times on the magnetic properties and microstructure of Sm2Fe17N3 magnetic powders were studied. The results show that the coercivity of Sm2Fe17N3 powders increases first and then decreases with the milling time increases from 0 min to 60 min. When the milling time is 12 min, the grain size of Sm2Fe17N3 phase decreases from 40.8 nm of the original powder to 31.8 nm. The powder has the highest coercivity of 875.6 kA/m, and the magnetic powder still maintains anisotropy. However, when the ball milling time is 30 mins, although the grain size is further reduced, the Sm2Fe17N3 decomposes to form soft magnetic phases such as SmN and α-Fe, resulting in a decrease in the coercivity of the magnet. When the milling time is 60 min, the coercivity of magnetic powders decreases to 477.6 kA/m. This work provides an effective way for the preparation of high-quality Sm2Fe17N3 powder precursors for the preparation of high-performance Sm2Fe17N3 bonded magnets.
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