Abstract Although the addition of other elements such as Mn to Sm2Fe17Nx compounds can change the magnetic properties, it also decreases saturation magnetization. In order to exploit the advantages of additional elements in Sm2Fe17Nx powder while maintaining a high saturation magnetization, a structure of Sm2Fe17Nx-core/Sm2(Fe,M)17Nx-shell is promising. This is the first report of such a core-shell powder obtained by a reduction-diffusion process. Mn3O4 was mixed with Sm-Fe and Sm2O3 powders followed by the reduction by Ca above 860 °C, and then samples were nitrided and washed after reduction-diffusion process. Core-shell Sm-Fe-N fine powder with a Mn-enriched Sm2(Fe,Mn)17Nx shell was thus successfully obtained. The thickness of the Mn enriched region was about 0.8 μm, and the crystal structure of the core-shell powder was Th2Zn17. The saturation magnetization and coercivity of the core-shell powder were 138.8 A·m2·kg−1 and 1001.7 kA·m−1, respectively. The saturation magnetization was slightly smaller than that of Mn-free Sm-Fe-N powder, whereas the coercivity of the core-shell powder was higher than that of Mn-free Sm-Fe-N powder. In addition, the saturation magnetization and coercivity were higher than those reported for Sm-Fe-Mn-N powder. The thermal stability of the Mn-diffused Sm-Fe-N core-shell powder was improved compared with Mn-free Sm-Fe-N powder.

中文翻译：

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还原扩散法制备Mn扩散Sm-Fe-N核壳粉体

摘要 虽然在Sm2Fe17Nx 化合物中加入Mn 等其他元素可以改变磁性，但也会降低饱和磁化强度。为了在保持高饱和磁化强度的同时发挥 Sm2Fe17Nx 粉末中附加元素的优势，Sm2Fe17Nx-核/Sm2(Fe,M)17Nx-壳结构很有前景。这是通过还原-扩散过程获得的这种核壳粉末的首次报道。Mn3O4 与 Sm-Fe 和 Sm2O3 粉末混合，然后在 860°C 以上用 Ca 还原，然后在还原扩散过程后对样品进行氮化和洗涤。因此成功地获得了具有富锰的 Sm2(Fe,Mn)17Nx 壳的核壳 Sm-Fe-N 细粉。Mn富集区的厚度约为0.8 μm，核壳粉末的晶体结构为Th2Zn17。核壳粉末的饱和磁化强度和矫顽力分别为138.8 A·m2·kg-1和1001.7 kA·m-1。饱和磁化强度略小于不含Mn的Sm-Fe-N粉末，而核壳粉末的矫顽力高于不含Mn的Sm-Fe-N粉末。此外，饱和磁化强度和矫顽力高于报道的 Sm-Fe-Mn-N 粉末。与不含 Mn 的 Sm-Fe-N 粉末相比，Mn 扩散的 Sm-Fe-N 核壳粉末的热稳定性得到提高。饱和磁化强度和矫顽力高于报道的 Sm-Fe-Mn-N 粉末。与不含 Mn 的 Sm-Fe-N 粉末相比，Mn 扩散的 Sm-Fe-N 核壳粉末的热稳定性得到提高。饱和磁化强度和矫顽力高于 Sm-Fe-Mn-N 粉末的报道。与不含 Mn 的 Sm-Fe-N 粉末相比，Mn 扩散的 Sm-Fe-N 核壳粉末的热稳定性得到提高。