Takagi Kenta, Hirayama Yusuke, Okada Shusuke, Yamaguchi Wataru, Ozaki Kimihiro
Magnetic Powder Metallurgy Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Nagoya, Japan.
Sci Technol Adv Mater. 2021 Mar 3;22(1):150-159. doi: 10.1080/14686996.2021.1875791.
Post-neodymium magnets that possess high heat resistance, coercivity, and are desired for future-generation motors. However, the candidate materials for post-neodymium magnets such as SmFeN and metastable magnetic alloys have certain process-related problems: low sinterability due to thermal decomposition at elevated temperatures, deterioration of coercivity during sintering, and the poor coercivity of the raw powder. Various developments in powder processing are underway with the aim of overcoming these problems. So far, the development of advanced powder metallurgy techniques has achieved SmFeN anisotropic sintered magnets without coercivity deterioration, and advances in chemical powder synthesis techniques have been successful in producing SmFeN fine powders with huge coercivity. The challenge of a new powder process is expected to open the way to realizing post-neodymium magnets.
钕后磁体具有高耐热性、矫顽力，是下一代电机所需要的。然而，钕后磁体的候选材料，如SmFeN和亚稳磁性合金，存在一些与工艺相关的问题：由于在高温下热分解导致烧结性低、烧结过程中矫顽力下降以及原料粉末的矫顽力差。为了克服这些问题，正在进行各种粉末加工方面的研发。到目前为止，先进粉末冶金技术的发展已经实现了无矫顽力恶化的SmFeN各向异性烧结磁体，化学粉末合成技术的进步也成功地生产出了具有巨大矫顽力的SmFeN细粉。一种新的粉末工艺的挑战有望为实现钕后磁体开辟道路。
