Scholarlink

<p>The coercivity of Sm–Fe–N/Zn magnets is strongly influenced by the composition and distribution of grain boundary phases. In this study, a Zn layer was uniformly deposited onto the surface of Sm–Fe–N powders via an innovative electrodeposition method, followed by a two-step thermal treatment process (hot-pressing + annealing) to precisely control the formation of the Γ-FeZn phase and the grain boundary structure. The results indicate that annealing at 430&#xa0;°C promotes the uniform distribution of the Γ-FeZn phase along the grain boundaries, achieving a coercivity of 14.60&#xa0;kOe—nearly three times higher than that of the untreated sample. Transmission electron microscopy (TEM) analysis reveals that increasing the annealing temperature enhances Zn mobility and diffusion at the grain boundaries, which facilitates the gradual formation of a continuous Γ-FeZn phase encapsulating the magnetic particles. This structure effectively suppresses exchange coupling between grains, thereby significantly enhancing coercivity. However, when the temperature exceeds 450&#xa0;°C, excessive Zn diffusion leads to the formation of a Sm–Fe(Zn)–N intermediate phase, which weakens the anisotropy field and causes a reduction in coercivity. Unlike previous studies that primarily focused on the presence of the Γ-FeZn phase, the present work achieves synergistic optimization via electrodeposition and temperature regulation, providing a deeper understanding of the intrinsic relationship among Zn diffusion, grain boundary evolution, and magnetic properties. These findings present a novel strategy and theoretical basis for the design of high-performance Sm–Fe–N magnets.</p> Graphical abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Grain boundary regulation and microstructural evolution of Sm–Fe–N magnets via Zn electrodeposition

  • 期刊论文

  • 发表日期：

    2025年8月13日

查看全文
  • Dong-Sheng Shi,
  • Jing-Wu Zheng,
  • Jia-Min Liu,
  • Wei Cai,
  • Heng Huang,
  • Hai-Bo Chen,
  • Liang Qiao,
  • Min Lin,
  • Yao Ying,
  • Wang-Chang Li,
  • Jing Yu,
  • Juan Li,
  • Ji Shi,
  • Sheng-Lei Che

摘要

The coercivity of Sm–Fe–N/Zn magnets is strongly influenced by the composition and distribution of grain boundary phases. In this study, a Zn layer was uniformly deposited onto the surface of Sm–Fe–N powders via an innovative electrodeposition method, followed by a two-step thermal treatment process (hot-pressing + annealing) to precisely control the formation of the Γ-FeZn phase and the grain boundary structure. The results indicate that annealing at 430 °C promotes the uniform distribution of the Γ-FeZn phase along the grain boundaries, achieving a coercivity of 14.60 kOe—nearly three times higher than that of the untreated sample. Transmission electron microscopy (TEM) analysis reveals that increasing the annealing temperature enhances Zn mobility and diffusion at the grain boundaries, which facilitates the gradual formation of a continuous Γ-FeZn phase encapsulating the magnetic particles. This structure effectively suppresses exchange coupling between grains, thereby significantly enhancing coercivity. However, when the temperature exceeds 450 °C, excessive Zn diffusion leads to the formation of a Sm–Fe(Zn)–N intermediate phase, which weakens the anisotropy field and causes a reduction in coercivity. Unlike previous studies that primarily focused on the presence of the Γ-FeZn phase, the present work achieves synergistic optimization via electrodeposition and temperature regulation, providing a deeper understanding of the intrinsic relationship among Zn diffusion, grain boundary evolution, and magnetic properties. These findings present a novel strategy and theoretical basis for the design of high-performance Sm–Fe–N magnets.

Graphical abstract