Browse > Article
http://dx.doi.org/10.4150/KPMI.2010.17.1.001

Coercivity Enhancement of Nd23Dy10Fe64TM2B1 Sintered Magnet by Convergent Heat Treatment  

Kim, Hoon-Sup (Department of Materials Science and Engineering, Hanyang University)
Kim, Se-Hoon (Department of Materials Science and Engineering, Hanyang University)
Kim, Jin-Woo (Department of Materials Science and Engineering, Hanyang University)
Kim, Young-Do (Department of Materials Science and Engineering, Hanyang University)
Publication Information
Journal of Powder Materials / v.17, no.1, 2010 , pp. 1-6 More about this Journal
Abstract
In this study, a convergent heat treatment was performed in certain temperature regions in order to control the microstructures of Nd-rich phases and to reduce thermal stress on grain boundaries which could be caused during expansion and shrinkage of Nd-rich and $Nd_2Fe_{14}B$ phases. The difference of thermal expansion coefficient between $Nd_2Fe_{14}B$ and Nd-rich phases is the mechanism for convergent heat treatment. The Nd-rich phases which were located in junctions could penetrate into the grain boundaries between $Nd_2Fe_{14}B$ phases due to the difference of thermal expansion coefficient. Through the convergent heat treatment, the microcracks that were observed in cyclic heat treatment were not observed and coercivity was increased to 34.05 kOe at 8 cycles.
Keywords
Nd-Fe-B sintered magnets; Convergent heat treatment; Thermocyclic; Magnetic properties;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
연도 인용수 순위
1 W. F. Li, T. Ohkubo and K. Hono: Acta Mater., 57 (2009) 1337-1346.   DOI   ScienceOn
2 R. K. Mishira, J. K. Chen and G. Thomas: J. Appl. Phys., 59 (1986) 2244   DOI
3 F. Vial, F. Joly, E. Nevalanien, M. Sagawa, K. Hiraga and K. T. Park: J. Magn. Magn. Mater., 242 (2002) 1329.   DOI   ScienceOn
4 R. Ramensh, G. Thomas and B. M. Ma: J. Appl. Phys., 70 (1991) 6453.   DOI
5 S. J. Chu: Ultra-strong permanent magnet materials, Ulsan Univ. Pub., Ulsan (1999); 주수증: 초강력 영구 자성체, 울산대학교 출판부, (1999)
6 S. H. Kim, H.-S. Kim, D. H. Kim and Y. D. Kim: J. Korean Powder Metall. Inst., 15 (2008) 471 (Korean).   DOI   ScienceOn
7 D. H. Kim: Study on the development of high performance Nd-rare earth permanent magnets by enhanced anisotropy, Ministry of Knowledge Economy, (2007); 김동환: 완전이방화에 의한 초고특성 Nd계희토류영구자석 개발에 관한 연구, 지식경제부, (2007).
8 M. Sagawa, S. Fujimura, N. Tpgawa and Y. Matsuura: J. Appl. Phys., 55 (1984) 2083.   DOI
9 D. Brown, B.-M. Ma and Z. Chen: J. Magn. Magn. Mater., 248 (2002) 432.   DOI   ScienceOn
10 D. Lemarchand, P. Vigier and B. Labulle: IEEE Trans. Magn., 26 (1990) 2649.   DOI   ScienceOn
11 H. Kromuller, K. D. Durst and G. Martinek: J. Magn. Magn. Mater., 69 (198) 149.   DOI   ScienceOn
12 Y. Tsubokawa, R. Shimizu, S. Hirosawa and M. Sagawa: J. Appl. Phys., 63 (1988) 3319.   DOI