Goto Sho, Kura Hiroaki, Watanabe Eiji, Hayashi Yasushi, Yanagihara Hideto, Shimada Yusuke, Mizuguchi Masaki, Takanashi Koki, Kita Eiji
Advanced Research and Innovation Center, DENSO Corporation, Aichi, 470-0111, Japan.
Institute of Applied Physics, University of Tsukuba, Ibaraki, 305-8573, Japan.
Sci Rep. 2017 Oct 16;7(1):13216. doi: 10.1038/s41598-017-13562-2.
Tetrataenite (L1-FeNi) is a promising candidate for use as a permanent magnet free of rare-earth elements because of its favorable properties. In this study, single-phase L1-FeNi powder with a high degree of order was synthesized through a new method, nitrogen insertion and topotactic extraction (NITE). In the method, FeNiN, which has the same ordered arrangement as L1-FeNi, is formed by nitriding A1-FeNi powder with ammonia gas. Subsequently, FeNiN is denitrided by topotactic reaction to derive single-phase L1-FeNi with an order parameter of 0.71. The transformation of disordered-phase FeNi into the L1 phase increased the coercive force from 14.5 kA/m to 142 kA/m. The proposed method not only significantly accelerates the development of magnets using L1-FeNi but also offers a new synthesis route to obtain ordered alloys in non-equilibrium states.
四方铁镍矿（L1-FeNi）因其优良性能，是一种很有前景的无稀土永磁体候选材料。在本研究中，通过一种新方法——氮插入和拓扑化学萃取（NITE），合成了具有高度有序性的单相L1-FeNi粉末。在该方法中，与L1-FeNi具有相同有序排列的FeNiN，是通过用氨气氮化A1-FeNi粉末形成的。随后，通过拓扑化学反应对FeNiN进行脱氮，得到有序参数为0.71的单相L1-FeNi。无序相FeNi向L1相的转变使矫顽力从14.5 kA/m增加到142 kA/m。所提出的方法不仅显著加速了使用L1-FeNi的磁体的开发，还提供了一种获得非平衡态有序合金的新合成途径。
