Makino Akihiro, Sharma Parmanand, Sato Kazuhisa, Takeuchi Akira, Zhang Yan, Takenaka Kana
Tohoku University, Sendai 980-8577, Japan.
Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
Sci Rep. 2015 Nov 16;5:16627. doi: 10.1038/srep16627.
Chemically ordered hard magnetic L10-FeNi phase of higher grade than cosmic meteorites is produced artificially. Present alloy design shortens the formation time from hundreds of millions of years for natural meteorites to less than 300 hours. Electron diffraction detects four-fold 110 superlattice reflections and a high chemical order parameter (S 0.8) for the developed L10-FeNi phase. The magnetic field of more than 3.5 kOe is required for the switching of magnetization. Experimental results along with computer simulation suggest that the ordered phase is formed due to three factors related to the amorphous state: high diffusion rates of the constituent elements at lower temperatures when crystallizing, a large driving force for precipitation of the L10 phase, and the possible presence of L10 clusters. Present results can resolve mineral exhaustion issues in the development of next-generation hard magnetic materials because the alloys are free from rare-earth elements, and the technique is well suited for mass production.
人工合成出了比宇宙陨石品位更高的化学有序硬磁L10-FeNi相。目前的合金设计将形成时间从天然陨石的数亿年缩短至不到300小时。电子衍射检测到已形成的L10-FeNi相的四重110超晶格反射和高化学有序参数（S 0.8）。磁化翻转需要超过3.5 kOe的磁场。实验结果与计算机模拟表明，有序相的形成归因于与非晶态相关的三个因素：结晶时较低温度下组成元素的高扩散速率、L10相析出的大驱动力以及L10团簇的可能存在。目前的结果可以解决下一代硬磁材料开发中的矿物枯竭问题，因为这些合金不含稀土元素，且该技术非常适合大规模生产。
