高密度块状钐铁氮磁体制备的研究进展

钐铁氮化合物(Sm₂Fe₁₇N₃)因具有比钕铁硼(Nd₂Fe₁₄B)更高的磁晶各向异性场和居里温度值及更少的稀土含量，成为新型稀土永磁材料研究热点。但是，由于钐铁氮在600℃左右会分解导致永磁性能消失，因此常规的高温烧结工艺并不适用于钐铁氮烧结磁体的制备，现只能将其与高分子材料复合用作塑磁材料，这就导致Sm₂Fe₁₇N₃的磁学性能无法得到充分发挥。因此，开发低温成型工艺制备全金属高密度块状磁体是获取高性能钐铁氮磁体的关键。经过30多年的努力，科研人员已开发出多种制备钐铁氮磁体的低温快速成型工艺，并获得最大磁能积达到199 k J/m³的高性能磁体。本研究将从磁体的制备方法出发，总结当前块状钐铁氮磁体的研究现状及面临的问题，尤其针对不同成型方法出现矫顽力下降的现象提出分析，并对其今后的发展做出展望。

Research progress of fabrication Sm-Fe-N bulk magnet with high density

Samarium iron nitrogen compound (Sm2Fe17N3) has become research hotspot of new rare earth permanent magnet materials because of its higher magnetocrystalline anisotropy field and Curie temperature value and less rare earth content than neodymium iron boron (Nd2Fe14B). However, since samarium iron nitrogen will decompose at 600 °C resulting the disappearance of permanent magnetic properties, the conventional high-temperature sintering process is not suitable for the preparation of samarium iron nitrogen sintered magnets and it can only be compounded with polymer materials as plastic magnets, which results in that the magnetic properties of Sm2Fe17N3 cannot be fully exerted. Therefore, the development of low-temperature forming process to prepare all-metal bulk magnets with high density is the key to obtaining high-performance samarium-iron-nitrogen magnets. After more than 30 years of hard work, researchers have developed a variety of low-temperature rapid prototyping processes for preparing samarium-iron-nitrogen magnets, and obtained high-performance magnets with a maximum magnetic energy product of 25MGOe. Starting from the preparation method of magnets, this paper summarizes the current research status and problems of bulk samarium-iron-nitrogen magnets, especially analyzes the phenomenon of coercivity decline in different fabrication methods, and makes prospect for its future development.