Presentation Information
[P1-5]Enhanced Magnetic Properties and Microstructural Characterization of Hot-Deformed (Ce,La)-Fe-B Magnets with Eutectic Alloy Incorporation
*Kyungmi Lee1, Ye Ryeong Jang1, Wooyoung Lee1 (1. Yonsei Univ. (Korea))
Keywords:
Permanent Magnet,Hot-Deformed
Due to increasing issues regarding the depletion and rising costs of heavy rare earth (HRE) elements, research on reducing HRE usage while maintaining high-performance permanent magnets has gained significant attention. As a result, light rare earth (LRE) elements, which are more abundant and cost-effective, have been widely explored as potential substitutes, with Ce being widely considered as a candidate. However, Ce-Fe-B alloys exhibit inferior magnetic properties compared to Nd-Fe-B due to the lower intrinsic performance of the 2:14:1 phase and the formation of the paramagnetic CeFe2 phase, which adversely affects the overall magnetic properties.
In this study, we aimed to enhance the magnetic properties of Ce-Fe-B-based magnets by producing fine-grained powders through the melt-spinning process, followed by hot deformation to develop anisotropic magnets. However, in Ce-Fe-B magnets, the formation of CeFe2 secondary phases inhibited grain alignment, resulting in low remanence and discontinuous, weakly defined grain boundaries, leading to a decrease in coercivity. To address this issue, we fabricated (Ce,La)-Fe-B magnets by partially substituting Ce with La and further improved the magnetic properties by incorporating a eutectic alloy.
The experimental results indicated that the Ce-Fe-B magnet exhibited minimal grain boundary formation after hot deformation due to the absence of a RE-rich phase. Additionally, the high concentration of CeFe2 phases inhibited diffusion, limiting the improvement in magnetic properties even after eutectic alloy incorporation. In contrast, in (Ce,La)-Fe-B magnets, the decrease in Ce content inhibited the formation of the CeFe2 phase, which enabled the formation of a RE-rich phase essential for grain boundary formation during hot deformation. Furthermore, eutectic alloy incorporation further inhibited CeFe2 formation, promoted grain boundary formation, and enhanced texture alignment.
As a result, the remanence and coercivity of the hot-deformed magnets were enhanced, achieving a maximum (BH)max of 5.7 MGOe in (Ce,La)-Fe-B magnets with a small amount of eutectic alloy incorporation.
In this study, we aimed to enhance the magnetic properties of Ce-Fe-B-based magnets by producing fine-grained powders through the melt-spinning process, followed by hot deformation to develop anisotropic magnets. However, in Ce-Fe-B magnets, the formation of CeFe2 secondary phases inhibited grain alignment, resulting in low remanence and discontinuous, weakly defined grain boundaries, leading to a decrease in coercivity. To address this issue, we fabricated (Ce,La)-Fe-B magnets by partially substituting Ce with La and further improved the magnetic properties by incorporating a eutectic alloy.
The experimental results indicated that the Ce-Fe-B magnet exhibited minimal grain boundary formation after hot deformation due to the absence of a RE-rich phase. Additionally, the high concentration of CeFe2 phases inhibited diffusion, limiting the improvement in magnetic properties even after eutectic alloy incorporation. In contrast, in (Ce,La)-Fe-B magnets, the decrease in Ce content inhibited the formation of the CeFe2 phase, which enabled the formation of a RE-rich phase essential for grain boundary formation during hot deformation. Furthermore, eutectic alloy incorporation further inhibited CeFe2 formation, promoted grain boundary formation, and enhanced texture alignment.
As a result, the remanence and coercivity of the hot-deformed magnets were enhanced, achieving a maximum (BH)max of 5.7 MGOe in (Ce,La)-Fe-B magnets with a small amount of eutectic alloy incorporation.
