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Title: Consolidation of Nd-Fe-B melt-spun ribbon by compression shearing method

Abstract

Commercially available Nd-Fe-B melt-spun ribbons (MQ powders) were consolidated at temperatures ranging from room temperature to 573 K in ambient atmosphere by the compression shearing method. The resultant bulk materials consisted of the Nd{sub 2}Fe{sub 14}B phase together with a small amount of the soft magnetic {alpha}-iron phase. The bulk material consolidated at room temperature was magnetically isotropic as was the case for the MQ powders. On the other hand, the bulk material consolidated at 573 K was found to be magnetically anisotropic and showed a remanence of 9.2 kG, higher than that of the MQ powders.

Authors:
; ;  [1];  [2]
  1. Department of Mechanical Science and Engineering, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016 (Japan)
  2. (Japan)
Publication Date:
OSTI Identifier:
20982864
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 9; Conference: 10. joint MMM/INTERMAG conference, Baltimore, MD (United States), 7-11 Jan 2007; Other Information: DOI: 10.1063/1.2709415; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; ATMOSPHERES; BORON ALLOYS; COMPRESSION; IRON ALLOYS; IRON-ALPHA; MAGNETIC MATERIALS; NEODYMIUM ALLOYS; POWDERS; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; TEMPERATURE RANGE 0400-1000 K; TERNARY ALLOY SYSTEMS

Citation Formats

Saito, Tetsuji, Takeishi, Hiroyuku, Nakayama, Noboru, and Department of Machine Intelligence and Systems Engineering, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuti, Honjyo, Akita 015-0055 Japan. Consolidation of Nd-Fe-B melt-spun ribbon by compression shearing method. United States: N. p., 2007. Web. doi:10.1063/1.2709415.
Saito, Tetsuji, Takeishi, Hiroyuku, Nakayama, Noboru, & Department of Machine Intelligence and Systems Engineering, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuti, Honjyo, Akita 015-0055 Japan. Consolidation of Nd-Fe-B melt-spun ribbon by compression shearing method. United States. doi:10.1063/1.2709415.
Saito, Tetsuji, Takeishi, Hiroyuku, Nakayama, Noboru, and Department of Machine Intelligence and Systems Engineering, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuti, Honjyo, Akita 015-0055 Japan. Tue . "Consolidation of Nd-Fe-B melt-spun ribbon by compression shearing method". United States. doi:10.1063/1.2709415.
@article{osti_20982864,
title = {Consolidation of Nd-Fe-B melt-spun ribbon by compression shearing method},
author = {Saito, Tetsuji and Takeishi, Hiroyuku and Nakayama, Noboru and Department of Machine Intelligence and Systems Engineering, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuti, Honjyo, Akita 015-0055 Japan},
abstractNote = {Commercially available Nd-Fe-B melt-spun ribbons (MQ powders) were consolidated at temperatures ranging from room temperature to 573 K in ambient atmosphere by the compression shearing method. The resultant bulk materials consisted of the Nd{sub 2}Fe{sub 14}B phase together with a small amount of the soft magnetic {alpha}-iron phase. The bulk material consolidated at room temperature was magnetically isotropic as was the case for the MQ powders. On the other hand, the bulk material consolidated at 573 K was found to be magnetically anisotropic and showed a remanence of 9.2 kG, higher than that of the MQ powders.},
doi = {10.1063/1.2709415},
journal = {Journal of Applied Physics},
number = 9,
volume = 101,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}
  • The microstructure of Nd-Fe-B magnets made from melt-spun ribbons differs significantly from that of the sintered magnets. An ideal two-phase microstructure of small Nd/sub 2/Fe/sub 14/B grains surrounded by a Nd-rich intergranular phase is easily achieved in the melt-spun magnets while sintered magnets invariably contain the boron-rich Nd/sub 1.1/Fe/sub 4/B/sub 4/ phase. This phase can form in the melt-spun alloys only when the cooling rates are slow and excess Nd and B are added deliberately. In those cases, this new phase appears as randomly distributed and randomly oriented grains of the same size as the Nd/sub 2/Fe/sub 14/B grains. Themore » Nd/sub 1.1/Fe/sub 4/B/sub 4/ grains are highly faulted in the Fe sublattice with their fault planes parallel to the (110) plane. Energy dispersive x-ray analysis and diffraction shows that this phase forms with varying Nd:Fe ratios in different grains. We have also found that the faults form in pure bulk samples of Nd/sub 1.1/Fe/sub 4/B/sub 4/ but not in pure NdCo/sub 4/B/sub 4/ samples. Possible antiphase boundaries arising from modulated Fe sublattice are seen. The faulted microstructure is believed to result from (a) sluggish kinetics of formation of this phase, (b) incommensurate crystal structure, and (c) weak bonding between the Nd chains and chains of Fe-B tetrahedra that make up the structure. Lorentz microscopy shows this phase to act as a weak barrier to domain wall motion.« less
  • This is a contemporary study of rapidly quenched Nd{sub 1.6}X{sub 0.4}Fe{sub 14}B magnetic materials (where X= Nd, Y, Ce, La, Pr, Gd and Ho). A 20% substitution of the Nd component from Nd{sub 2}Fe{sub 14}B can bring about some commercial advantage. However, there will be some compromise to the magnetic performance. Light rare earth elements are definitely more abundant (Y, Ce, La) than the heavier rare earth elements, but when they are included in RE{sub 2}Fe{sub 14}B magnets they tend to lower magnetic performance and thermal stability. Substituting heavy rare earth elements (Gd, Ho) for Nd in Nd{sub 2}Fe{sub 14}Bmore » improves the thermal stability of magnets but causes a loss in magnet remanence.« less
  • Coercivity optimization studies were done on melt-spun nanocomposite Nd{sub 4}R{sub 2}Fe{sub 87{minus}{ital x}}NbT{sub x}B{sub 6} (R=Nd,Y,Dy; T=Ag,Cu) isotropic ribbon samples. The maximum attainable coercivities, after adjusting the annealing time, were found to be very sensitive to the annealing temperatures. The optimum magnetic properties [{ital H}{sub {ital C}}=3.9 kOe, (BH){sub max}=10 MGOe] were obtained by annealing at 750{endash}775{degree}C for a few minutes. Optimization by flash annealing gave similar results. Microstructural studies show that the grain size is greater than the theoretically predicted grain size for optimum coupling between the hard and the soft phase. With the annealing conditions used, Nd{sub 4}Dy{submore » 2}Fe{sub 87}NbB{sub 6} samples gave moderate coercivities and in Nd{sub 4}Y{sub 2}Fe{sub 87}NbB{sub 6} samples the coercivity was reduced more than the expected reduction in the anisotropy field due to the presence of Y. {copyright} {ital 1996 American Institute of Physics.}« less
  • The paper deals with plasma-assisted PVD of {alpha}-Fe thin film onto the melt-spun Nd-Fe-B-Co ribbons. The parameters of the plasma created by a planar rectangular ECR plasma source with a multipolar magnetic field and a double-slot antenna were as follows: electron density up to 1x10{sup 10} cm{sup -3}, electron temperature {approx}22 eV, the current density of ion flow to grounded disk-substrate was equal to {approx}0.5 mA/cm{sup 2} at the gas flow of 1 sccm, the microwave power was up to 300W. After degreasing and ultrasonic washing of Nd-Fe-B-Co ribbons, follow by ion etching, the deposition process was realized at amore » pulsed voltage bias of -1000 V with frequency 100 Hz, total current on the target 240 mA, current density 2.9 mA/cm{sup 2}. The deposition rate of 0.0083 {mu}m/min was achieved. The process continued for 2 hour. It was found that the magnetic melt-spun ribbons were homogeneously coated with the {alpha}-Fe film having a typical thickness of 1 {mu}m.« less
  • The large values of remanence observed in isotropic melt-spun R-Fe-Al-B-Si samples have been investigated by correlating the magnetic properties with the microstructure. Transmission electron microscope studies showed that the highest values of reduced remanence m/sub R/ are obtained in samples with very fine Nd/sub 2/Fe/sub 14/B-type grains having a size of about 180 A. The increased reduced remanence can be explained by the large interaction among the magnetic moments of neighboring grains which is caused by the large surface-to-volume ratio of the fine grains.