Faceted shell structure in grain boundary diffusion-processed sintered Nd-Fe-B magnets

被引：100

作者：

Seelam, U. M. R. ^{[1
]}

Ohkubo, T. ^{[1
]}

Abe, T. ^{[1
]}

Hirosawa, S. ^{[1
]}

Hono, K. ^{[1
]}

机构：

[1] Natl Inst Mat Sci, Elements Strategy Initiat Ctr Magnet Mat, Tsukuba, Ibaraki 3050047, Japan

来源：

JOURNAL OF ALLOYS AND COMPOUNDS | 2014年 / 617卷

基金：

日本科学技术振兴机构;

关键词：

Nd-Fe-B; Permanent magnet; Coercivity; Dy; Grain boundary diffusion process; COERCIVITY ENHANCEMENT;

D O I：

10.1016/j.jallcom.2014.07.166

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Dysprosium enriched shell structure formed by the grain boundary diffusion process (GBDP) of a sintered Nd-Fe-B magnet was characterized by using scanning electron microscopy, electron back-scattered diffraction and transmission electron microscopy. Faceted core-shell interfaces with an abrupt change in Dy concentration suggest the Dy-rich shells are formed by the solidification of the liquid phase during cooling from the GBDP temperature. The Nd-rich phases are almost free from Dy, and their quantity near the surface of a bulk sample is much higher than that in the center, indicating that a higher fraction of a liquid phase exists near the surface during processing at 900 degrees C. These microstructural features are explained on the basis of the phase equilibrium between Nd and Nd2Fe14B at the processing temperature and subsequent cooling. Based on the results, we discuss the coercivity enhancement by the GBDP using Dy vapor. (C) 2014 Elsevier B.V. All rights reserved.

引用

页码：884 / 892

页数：9

共 29 条

[21] Effect of Diffusion Annealing on the Hysteretic Properties of Sintered Nd-Fe-B Magnets [J].

Popov, A. G. ;

Vasilenko, D. Yu. ;

Puzanova, T. Z. ;

Shitov, A. V. ;

Vlasyuga, A. V. .

PHYSICS OF METALS AND METALLOGRAPHY, 2011, 111 (05) :471-478

[22] NEW MATERIAL FOR PERMANENT-MAGNETS ON A BASE OF ND AND FE [J].

SAGAWA, M ;

FUJIMURA, S ;

TOGAWA, N ;

YAMAMOTO, H ;

MATSUURA, Y .

JOURNAL OF APPLIED PHYSICS, 1984, 55 (06) :2083-2087

[23] Microstructural and compositional characterization of terbium-doped Nd-Fe-B sintered magnets [J].

Samardzija, Zoran ;

McGuiness, Paul ;

Soderznik, Marko ;

Kobe, Spomenka ;

Sagawa, Masato .

MATERIALS CHARACTERIZATION, 2012, 67 :27-33

[24] The mechanism of coercivity enhancement by the grain boundary diffusion process of Nd-Fe-B sintered magnets [J].

Sepehri-Amin, H. ;

Ohkubo, T. ;

Hono, K. .

ACTA MATERIALIA, 2013, 61 (06) :1982-1990

[25]

Suzuki H., 2009, J APPL PHYS, V105

[26] Microstructure analysis of sintered Nd-Fe-B magnets improved by Tb-vapor sorption [J].

Watanabe, Natsuki ;

Itakura, Masaru ;

Kuwano, Noriyuki ;

Li, Deshan ;

Suzuki, Shunji ;

Machida, Ken-ich .

MATERIALS TRANSACTIONS, 2007, 48 (05) :915-918

[27] Multi-phase EBSD mapping and local texture analysis in NdFeB sintered magnets [J].

Woodcock, T. G. ;

Gutfleisch, O. .

ACTA MATERIALIA, 2011, 59 (03) :1026-1036

[28] Optimisation of the processing of Nd-Fe-B with dysprosium addition [J].

Yan, Gaolin ;

McGuiness, P. J. ;

Farr, J. P. G. ;

Harris, I. R. .

JOURNAL OF ALLOYS AND COMPOUNDS, 2010, 491 (1-2) :L20-L24

[29]

ZHANG LY, 1988, J MAGN MAGN MATER, V71, P203, DOI 10.1016/0304-8853(88)90086-8

← 1 2 3 →