α″-Fe16N2基的永磁各向异性纳米片的制备和磁性调控

The α″-Fe16N2 with giant saturation magnetiation is a potential material for rare earth free permanent magnets or soft phase material in nanocomposited permanent magnets. However, the fabrication of pure phase and obtaining magnetic anisotropy in α″-Fe16N2 face enormous difficulties. This proposal presents a new nitridation avenue for anisotropic α″-Fe16N2 after fabricating α-Fe nanoflakes with large specific surface and texture. The relation between size/shape/texture of α-Fe and purity/magnetic properties of nitrides would be contrasted based the characterization of composition and microstructure. Then the high purity anisotropic α″-Fe16N2 based nanoflakes would be achieved via optimizing the technique parameters and adding other elements, and the intrinsic magnetic parameters and magnetization reversal process would be searched. The author have fabricated α-Fe nanoflakes with large specific surface and texture and anisotropic nitrides in previous work.

具有极大饱和磁化强度的α″-Fe16N2材料，作为一种非稀土永磁材料或者纳米复合永磁中的软磁相材料，均有很大研究价值，但是长期以来在合成纯相和获得磁各向异性等方面存在难以解决的困难。本项目提出先制备出具有大比表面积和织构的α-Fe纳米片（片状颗粒），然后氮化获得具有磁各向异性的α″-Fe16N2纳米片的新思路。在对α-Fe纳米片及其氮化产物的相成分、结构、微观形貌和磁性能进行表征的基础上，建立起α-Fe纳米片的尺寸、扁平化微观形貌以及织构，与氮化产物的相成分和磁性能之间的关系。在此基础上将全面优化制备α-Fe纳米片和氮化反应的技术，并结合元素添加等方法，获得高纯度的各向异性α″-Fe16N2基纳米片，并研究其内禀磁性和磁化翻转机理。申请人根据此研究思路在前期预研究中已经初步制备了具有织构和大比表面积的α-Fe纳米片，并证实了其氮化产物具有织构和磁各向异性。

为了探索新型非稀土永磁材料，本项目首先采用了先制备出具有大比表面积和织构的α-Fe纳米片（片状颗粒），然后氮化获得具有磁各向异性的α’’-Fe16N2纳米片的新思路，获得高纯度的各向异性α’’-Fe16N2基纳米片，并研究其内禀磁性和磁化翻转机理。另外，本项目还采用表面活性剂辅助高能球磨的方法，制备了具有高磁能积的各向异性SmPrCo纳米片，展示出色的磁性能。本项目还探索了另一种新型的基于形状各向异性的非稀土永磁材料：Co纳米线，并利用计算软件对其磁硬化机理进行了模拟。