摘要
采用储量丰富的Ce元素部分替代Nd-Fe-B磁体中的Nd,以实现Ce稀土的高质化利用,是近年来稀土永磁领域的研究热点.本工作以Tb-Al-Ca合金为扩散源,研究了Ce含量及扩散工艺对品界扩散Nd-Ce-Fe-B磁体微观结构和磁性能的影响.Ce含量较低的品界扩散磁体中,Tb元素在主相品粒外侧,形成高磁品各向异性场的壳层结构,网状分布的Al元素作为非磁性相包裹主相品粒,隔绝主相品粒之间的交换耦合,使磁体矫顽力增加.Ce含量较高的晶界扩散磁体中,形成的富Tb壳层较厚,Al元素扩散进入主相品粒内部,导致剩磁降低,隔绝主相品粒交换耦合作用降低,矫顽力增量较小.
Abstract
The Ce elements with high-abundance partially replacing Nd in the Nd-Fe-B magnets can achieve high quality utilization of Ce elements,which is a hot research topic in the field of rare earth permanent mag-nets.Effects of grain boundary diffusion process and Ce content on the microstructure and magnetic properties of grain boundary diffused(GBD)Nd-Ce-Fe-B magnets were investigated using Tb-Al-Ga alloy as the diffusion source.It is shown that in the grain boundary diffused magnets with lower Ce content,Tb elements mainly form shell structure with high magneto-crystalline anisotropy field surrounding main phase grains,and Al elements wrap the main phase grains as non-magnetic phase,isolating exchange coupling between adjacent main phase grains.Therefore,the coercivity of the grain boundary diffused magnets increases substantially.In the grain boundary diffused magnets with higher Ce content,the thickness of Tb-rich shell is increasing.Al elements dif-fuse into the main phase grains resulting in remanence in decreasing and can not form non-magnetic phase to isolate the main phase grains leading to the decrease of coercivity.
基金项目
国家重点研发计划项目(2021YFB3503002)
国家重点研发计划项目(2022YFB3503303)
NETL
NSTL
万方数据