添加CaF_2对烧结稀土永磁体性能的影响

Effect of adding CaF_2 on the performance of sintered rare earth permanent magnets

用添加CaF2的方法制备了烧结Nd-Fe-B和烧结Sm-Co复合磁体,并对磁体的性能进行了分析研究。实验结果表明:在添加CaF2的烧结Nd-Fe-B复合磁体的电阻率增大,但其磁性能有一定程度的下降;而添加CaF2的烧结Sm-Co复合磁体,由于制备工艺过程中的氧化问题,导致磁体的磁性能严重下降。扫描电镜分析表明,烧结Sm-Co/CaF2复合磁体中没有形成1:5相和2:17R相的微观组织;在烧结Nd-Fe-B/CaF2复合磁体中,CaF2只存在于晶界富Nd相中,对磁体的微观组织没有太大的影响,烧结Nd-Fe-B磁体适合用添加CaF2的方法制备高电阻率的复合磁体。

Sintered Nd - Fe - B and Sm - Co composite magnets were prepared by adding calcium flu- oride and their properties were investigated. Experimental results show that the electrical resistance of the sintered Nd - Fe - B magnets with CaF2 increased, but their magnetic properties decrease to some extent. The magnetic properties of the sintered Sm - Co magnet with CaF2 decreased seriously due to the oxidation during the preparation process. The scanning electron microscopy results show that there did not form 1：5 phase and 2 ： 17R phase in microstructure of the sintered Sm - Co/CaF2 composite magnet. The CaF2 was distributed in the grain boundary attached to the Nd - rich phase and has a lit- tle effect on the microstructure of sintered Nd - Fe - B/CaF2 composite magnet. It is a way to increase the electrical resistance for the sintered Nd -Fe -B magnet by adding CaF2.