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http://dx.doi.org/10.4150/KPMI.2010.17.5.359

Improvement of the Magnetic Properties of (Nd, Dy)-Fe-B Sintered Magnets by Modification of HD and Annealing Processes  

NamKung, S. (Department of Materials and Metallurgical Engineering, Graduate School, Sunmoon University)
Lee, Y.H. (Department of Materials and Metallurgical Engineering, Graduate School, Sunmoon University)
Kim, M.K. (Department of Materials and Metallurgical Engineering, Graduate School, Sunmoon University)
Jang, T.S. (Department of Materials and Metallurgical Engineering, Graduate School, Sunmoon University)
Publication Information
Journal of Powder Materials / v.17, no.5, 2010 , pp. 359-364 More about this Journal
Abstract
In an attempt to optimize the magnetic properties of (Nd, Dy)-Fe-B sintered magnets, hydrogenation and post-sintering heat treatment processes were investigated at various hydrogenation temperatures and heat treatment temperatures. The coercivity of (Nd, Dy)-Fe-B sintered magnets hydrogenated at $400^{\circ}C$ increased to about 1.2 kOe without any detrimental effect on the remanence. Moreover, the coercivity of the magnets was enhanced further by a consecutive $2^{nd}$ and $3^{rd}$ step heat treatment. These results eventually leaded to the reduction of the Dy content in a high coercive (> 30 kOe) (Nd, Dy)-Fe-B sintered magnets, as much as 10%.
Keywords
Nd-Fe-B magnets; Hydrogen decrepitation; Jet-milling; Sintering; Heat-treatment;
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1 M. Sagawa, S. Fujimura, H. Yamamoto and Y. Matsura: J. Appl. Phys., 55 (1984) 2083.   DOI
2 J.J. Croat, J.F. Herbst, R.W. Lee and F.E. Pinkerton: J. Appl. Phys., 55 (1984) 2078.   DOI
3 Y. Kaneko; Proc. 16th Int. Workshop on REPM and their Applications, 2 (2000) 83.
4 H. Nagata and M. Sagawa: Proc. 17th Int. Workshop on REPM and their Applications, (2002) 354.
5 M. Uehara: J. Magn. Magn. Mater., 284 (2004) 281   DOI   ScienceOn
6 S.J. Chu: Ultra-strong permanent magnet materials, Ulsan Univ. Pub., Ulsan, (1999).
7 R.K. Mishra, J.K. Chen, G. Thomas: J. Appl. Phys., 59 (1986) 2244.   DOI
8 F. Vial, F. Joly, E. Nevalainen, M. Sagawa, K. Hiraga and K.T. Park: J. Magn. Magn. Mater., 242-245 (2002) 1329.   DOI   ScienceOn
9 W.F. Li, T. Ohkubo, K. Hono: Acta Mater., 57 (2009) 1337.   DOI   ScienceOn
10 D.W. Park, T.H. Kim, S.R.Lee, D.H. Kim, and T.S. Jang: J. Appl. Phys., 107 (2010) 09A737.   DOI   ScienceOn