Studies of microstructure and magnetic properties in sintered mixed rare earth (MRE) -Fe-B magnets (MRE = Nd plus La plus Dy)

TitleStudies of microstructure and magnetic properties in sintered mixed rare earth (MRE) -Fe-B magnets (MRE = Nd plus La plus Dy)
Publication TypeJournal Article
Year of Publication2011
AuthorsTang W, Wu YQ, Dennis KW, Oster NT, Kramer MJ, Anderson IE, McCallum RW
Journal TitleJournal of Applied Physics
Volume109
Pages07a704
Date Published04/01
Type of ArticleProceedings Paper
ISBN Number0021-8979
Accession NumberISI:000289949000222
Keywordsr2fe14b
Abstract

Sintered [Nd-0.45(LarDy1)(1/(r+1)*0.55)](2.6)Fe14B magnets (r = 1 to 3) were studied. Magnetic properties and microstructures of the magnets were investigated by magnetic measurements and electron microprobe analysis. The microstructure of magnets consists of a mixed rare-earth (MRE)(2)Fe14B (2: 14: 1) phase matrix having a grain size of similar to 8 mu m and a rare earth (RE)-rich grain boundary phase. The grain boundaries are rich in La and Nd but depleted in Dy, while the La, Nd, and Dy contents are constant across the 2: 14: 1 grains. The coercivity and temperature stability of magnets are improved with increasing Dy content. A (BH)(max) of 21.1 MGOe at room temperature is obtained in the magnet with r = 1. Temperature coefficients of alpha = -0.06 and beta = -0.48% degrees C were also obtained, which is comparable to those of Nd-based magnets with the best temperature stability. Unfortunately, the improvement of coercivity and its temperature coefficient is mainly achieved by adding greater amounts of Dy and DyF3, which leads to low (BH)(max) values and high magnet costs. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3549580]

URL<Go to ISI>://000289949000222
DOI10.1063/1.3549580
Alternate JournalJ. Appl. Phys.