Development of high performance Fe-based magnets utilizing computer analysis and crystallization from amorphous state

对nd - fe -b基纳米复合磁体进行了计算机模拟，得到了以下结果：(1)由60%软磁相和40% Nd_2Fe_<14>B组成的磁体，晶粒直径约为20nm，磁体能量积最大。(2)晶间交换相互作用强度的波动会使纳米复合磁体的磁性能恶化。(3)通过控制磁体组成的粒径，可以制备两种磁体。其中一种具有良好的磁化性能，另一种具有良好的反冲性能。基于以上结果，我们尝试用Nd-Fe-B非晶合金制备Nd-Fe-B基纳米复合磁体。结果表明：(1)含60%软磁相的磁体具有良好的硬磁性能。(2)为了抑制晶间交换作用强度的波动，在Fe_3B和Nd_2Fe_<14>B相之间制备了非晶Fe-Si-B相磁体。然而，由于晶粒直径和软磁相的数量不满足上述条件，硬磁性能没有得到改善。(3)通过控制非晶Nd-Fe-B合金的结晶条件，制备了具有良好磁化性能和良好后坐力的两种磁体。

The following results were obtained by computer simulation for Nd-Fe-B-based nanocomposite magnets.(1) Large maximum energy product is obtained in magnets composed of 60% soft magnetic phases and 40% Nd_2Fe_<14>B with about 20nm grain diameter.(2) Fluctuation of the strength of intetgrain exchange interaction deteriorates magnetic properties of nanocomposite magnets.(3) Two kinds of magnets can be prepared by controlling grain diameter consisting of magnets. One of them has good magnetizability and the other has good recoil properties.Based on the above results, we tried to prepare Nd-Fe-B-based nanocomposite magnets from Nd-Fe-B amorphous alloys. The results are :(1) Good hard magnetic properties were obtained in magnets including 60% soft magnetic phases.(2) In order to suppress fluctuation of the strength of intergrain exchange interaction, magnets with amorphous Fe-Si-B phase between Fe_3B and Nd_2Fe_<14>B phases were prepared. However, an improvement in hard magnetic properties was not achieved because the grain diameter and the amount of soft magnetic phases did not satisfy the above-mentioned conditions.(3) Two kinds of magnets, magnets with good magnetizability or those with good recoil properties, were prepared by controlling crystallization condition of amorphous Nd-Fe-B alloys.