New aspects of Nd{endash}Fe{endash}B-based hydrogenation-disproportionation-desorption-recombination powders and anisotropic bonded magnets made from them: Microstructure and magnetic properties (invited)
- Research and Development Division, Sumitomo Special Metals Company, Limited, 2-15-17 Egawa, Shimamoto-cho, Osaka 618 (Japan)
- Corporate Research and Development Laboratories, Sumitomo Metal Industries, 1-8 Fuso-cho, Amagasaki 660 (Japan)
Recent progress in the understanding of the texture formation mechanism in the hydrogenation-disproportionation-desorption-recombination (HDDR) process, improvements of stability with regard to thermal and structural losses, and the state-of-the-art performance of both compression and injection molded magnets made from the newly developed anisotropic HDDR powders are reported. Transmission electron microscopy observations of disproportionated Nd{endash}Fe{endash}Co{endash}Ga{endash}Zr{endash}B alloys have revealed the existence of finely dispersed crystallites of Nd{sub 2}(Fe,Co,Ga){sub 14}B which have a common crystallographic orientation. It is proposed that, upon removal of hydrogen, the hydrogen-disproportionated structure recombines from these crystallites to form textured submicron crystallites of the 2:14:1 phase. Using highly anisotropic HDDR powders, energy products (BH){sub max} exceeding 170 kJ/m{sup 3} (21 MGOe) have been obtained on compression-molded resin-bonded magnets and 130 kJ/m{sup 3} (16 MGOe) on injection-molded ones. High coercivity HDDR powders with an intrinsic coercivity (H{sub cJ}) exceeding 1.27 MA/m (16 kOe) have also been obtained by replacing part of Nd with Dy, which enabled improvement of thermal stability. It is shown that the degradation of magnetic performance of resin-bonded HDDR magnets is prevented by eliminating pore formation during the molding process. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 496524
- Report Number(s):
- CONF-961141-; ISSN 0021-8979; TRN: 97:016217
- Journal Information:
- Journal of Applied Physics, Vol. 81, Issue 8; Conference: 41. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 12-15 Nov 1996; Other Information: PBD: Apr 1997
- Country of Publication:
- United States
- Language:
- English
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