ABSTRACT

Permanent magnets, and particularly rare earth magnets such as Nd-Fe-B, have attracted much attention because of their magnetic properties. There are two well-established techniques for obtaining sintered magnets and bonded Nd-Fe-B magnets. Powder metallurgy is used to obtain high-performance anisotropic sintered magnets. To produce bonded magnets, either melt-spinning or the hydrogenation, disproportionation, desorption, and recombination process is used to produce magnet powders, which are then mixed with binders. Since the development of Nd-Fe-B magnets, several kinds of intermetallic compounds have been reported, such as Sm₂Fe₁₇N_x and Sm(Fe,M)₁₂ (M: Ti, V, etc.). However, it is difficult to apply a liquid-phase sintering process similar to the one used for Nd-Fe-B sintered magnets in order to produce high-performance Sm-Fe–based sintered magnets because of the low decomposition temperature of the compound and the lack of a liquid grain boundary phase like that in the Nd-Fe-B system. Therefore, bonded magnets are useful in the production of bulk magnets using these Sm-Fe-based compounds. This article reviews recent progress in our work on the development of high-performance bonded magnets using Nd₂Fe₁₄B and Sm₂Fe₁₇N_x compounds.

摘要

永磁体，特别是钕铁硼等稀土磁体，因其磁性而备受关注。有两种成熟的技术可用于获得烧结磁体和粘结 Nd-Fe-B 磁体。粉末冶金用于获得高性能各向异性烧结磁体。为生产粘结磁体，使用熔融纺丝或氢化、歧化、解吸和复合工艺来生产磁粉，然后将其与粘合剂混合。自从Nd-Fe-B磁体的发展以来，已经报道了几种金属间化合物，如Sm ₂ Fe ₁₇ N _x和Sm(Fe,M) ₁₂（M：钛、钒等）。然而，由于化合物的分解温度低，很难应用类似于用于 Nd-Fe-B 烧结磁体的液相烧结工艺来生产高性能 Sm-Fe 基烧结磁体。缺乏像 Nd-Fe-B 系统那样的液态晶界相。因此，粘结磁体可用于使用这些 Sm-Fe 基化合物生产大块磁体。本文回顾了我们使用 Nd ₂ Fe ₁₄ B 和 Sm ₂ Fe ₁₇ N _x化合物开发高性能粘结磁体的最新进展。