Grain boundary restructuring of multi-main-phase Nd-Ce-Fe-B sintered magnets with Nd hydrides

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	Grain boundary restructuring of multi-main-phase Nd-Ce-Fe-B sintered magnets with Nd hydrides
	Ma, Tianyu; Yan, Mi; Wu, Kaiyun; Wu, Bo; Liu, Xiaolian; Wang, Xuejiao; Qian, Zeyu; Wu, Chen; Xia, Weixing
刊名	ACTA MATERIALIA
	2018
卷号	142 页码:18-28
关键词	Permanent-magnets Coercivity Enhancement Microstructure Temperature Substitution Dependence Alloy Pr Dy
英文摘要	Multi-main-phase (MMP) Nd-Ce-Fe-B magnets prepared by sintering the mixture of Ce-free and Ce-containing RE2Fe14B (RE, rare earth) powders have been found to possess superior magnetic properties to the single-main-phase (SMP) ones. Purpose of this work is to further enhance the coercivity through restructuring the grain boundaries (GBs), which have strong influence on the short-range exchange coupling between adjacent grains. By incorporating 4 wt.% NdHX powders as the intergranular additive, coercivity of the (Pr, Nd)(22.3)Ce(8.24)Fe(bal)B0.98 (wt.%) MMP magnet has been substantially increased from 8.2 kOe to 13.1 kOe. Magnetic domain characterizations and the recoil loop measurements showed that the exchange coupling between adjacent grains has been weakened significantly due to the formation of continuous and smooth RE-rich GBs by the extra Nd after NdHX dehydrogenation. Elemental distribution analysis revealed that thicker Nd-rich 2:14:1 shells with stronger magnetocrystalline anisotropy have been formed in the outer region of the Ce-rich main phase grains, which is beneficial to enhance their effective anisotropy. In addition, the Ce-rich 2:14:1 shells surrounding the Nd-rich 2:14:1 grain cores became thinner, which is beneficial to weaken the magnetic dilution effect of such grains. Micromagnetic simulation results also suggest that the coercivity can be further enhanced once the grain boundary is nonmagnetic. Technically, enriching RE elements or reducing Fe content can weaken the ferromagnetism of the grain boundary phase as well as the exchange coupling between adjacent grains. The above findings might shed new insights into enhancing the coercivity of low cost Nd-Ce-Fe-B magnets. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
学科主题	Materials Science ; Metallurgy & Metallurgical Engineering
语种	英语
公开日期	2018-12-04
内容类型	期刊论文
源URL	[http://ir.nimte.ac.cn/handle/174433/16947]
专题	2018专题
推荐引用方式 GB/T 7714	Ma, Tianyu,Yan, Mi,Wu, Kaiyun,et al. Grain boundary restructuring of multi-main-phase Nd-Ce-Fe-B sintered magnets with Nd hydrides[J]. ACTA MATERIALIA,2018,142:18-28.
APA	Ma, Tianyu.,Yan, Mi.,Wu, Kaiyun.,Wu, Bo.,Liu, Xiaolian.,...&Xia, Weixing.(2018).Grain boundary restructuring of multi-main-phase Nd-Ce-Fe-B sintered magnets with Nd hydrides.ACTA MATERIALIA,142,18-28.
MLA	Ma, Tianyu,et al."Grain boundary restructuring of multi-main-phase Nd-Ce-Fe-B sintered magnets with Nd hydrides".ACTA MATERIALIA 142(2018):18-28.