(Nd,Pr,Ce)-Fe-B磁体的组织与磁学性能

为开发低成本烧结钕铁硼磁体,用30% Ce替代(Nd_0.75Pr_0.25)_32.69Fe_66.25B_1.06磁体中的Nd和Pr,研究了磁体在烧结及回火过程中的组织结构和磁学性能变化.结果表明,取向压坯在1030~1080℃烧结2 h后,随烧结温度升高,磁学性能下降,烧结温度为1030℃时综合磁学性能均最好.烧结态Ce替代磁体的综合磁学性能优于未替代磁体.一级回火后,相组成和晶粒尺寸基本不变,边界结构也未发生明显变化,磁体性能基本不变,或有少量下降.二级回火后,晶界明显改善,获得较清晰且平直的晶界,磁体矫顽力均得到大幅提高.Ce替代磁体的剩磁、矫顽力和磁能积均稍低于未替代磁体. 

Microstructure and magnetic properties of (Nd,Pr,Ce)-Fe-B magnets

To develop low-cost sintered Nd-Fe-B magnets, 30% Ce was used to substitute for Nd and Pr in magnets with the nominal compositional (Nd_0.75Pr_0.25)_32.69Fe_66.25B_1.06. The microstructure and magnetic properties of the magnets were studied during the processes of sintering and tempering. It is found that the magnetic properties of the orientated compacts decrease with the sintering temperature increasing from 1030 to 1080 ℃, and the magnets sintered at 1030 ℃ for 2 h exhibit the best magnetic properties. Compared with the non-substituted magnets, the Ce-substituted magnets show higher magnetic properties. The phase composition and grain size do not show obvious change along boundary structure by one-order tempering, and the magnetic properties of the magnets keep the same, or decrease slightly. By two-order tempering, the eoercivity of the magnets is greatly improved by optimization of boundary microstructure, with more clear and straight boundaries. The remanence, coercivity, and maximum energy product of the Ce-substituted magnets are slightly lower than those of the non-substituted magnets.