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Relations of Corrosion Resistance, Coercivity, and Magnetizability of Modified Nd-Fe-B Sintered Magnets to Their Microstructure

  • Satoshi Hirosawa (a1), Koki Tokuhara (a1), Shuji Mino (a1), Toshiyuki Matsui (a2), Kenji Morii (a2) and Yutaka Nakayama (a2)...

Abstract

Brief reviews on corrosion and coercivity mechanisms of sintered Nd-Fe-B magnets are given. Results of recently undertaken transmission electron microscopic study of Nd15 - Fe78-xCoxB7 sintered magnets (x = 3, 6 and 10) are presented. Micro-beam electron diffraction patterns obtained from Nd-Co phases in these magnets could be indexed according only to an orthorhombic cell of Nd3 Co among the binary Nd-Co compounds for x = 3 to 10. Relations of coercivity and magnetizability of this type of magnets to their microstructure are discussed in connection to the effects of V or Mo addition which are to enhance coercivity and to improve magnetizability. It is suggested that a decrease in the local demagnetization effects resulting from a decrease in the width of the grain size distribution due to these-additives is the origin of the enhancement of coercivity and the improvement of magnetizability.

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1. Sagawa, M., Fujimura, S., Togawa, N., Yamamoto, H., Matsuura, Y., J. Appl. Phys. 55, 2083 (1984).
2. Ramesh, R., Chen, J. K. and Thomas, G., J. Appl. Phys. 61(8), 29932998 (1987).
3. Tenaud, P., Vial, F. and Sagawa, M., IEEE Trans. Magn. MAG–26, 1930 (1990); M. Sagawa, P. Tenaud, F. Vial and K. Hiraga, IEEE Trans. Magn., MAG-26, 1957 (1990); S. Hirosawa, H. Tomizawa, S. Mino, and A. Hamamura, IEEE Trans. Magn., MAG-26, 1960 (1990).
4. Kim, A. S., J. Mater. Eng. 11(1), 95101 (1989).
5. Nakamura, H., Fukuno, A, Yoneyama, T., in Proc. The 10th Int. Workshop on Rare-Erath Magnets and Their Applications, Pt. II (The Society of Nontraditional Technology, Tokyo, 1989), p. 315.
6. Tokuhara, K. and Hirosawa, S., presented at the 35th Annual Conference of Magnetism and Magnetic Materials, San Diego, CA. 1990 (to be published in J. Appl. Phys.).
7. Narasimhan, K. S. V. L., Willman, C. and Dullis, E., U. S. Patent No. 4588439 (1986).
8. Kim, A. S., Camp, F. E. and Dulis, E. J., IEEE. Trans. Magn. MAG–26, 1936 (1990).
9. Ohashi, K., Tawara, Y., Yokoyama, T. and Kobayashi, N., in Proc. 9th Int. Workshop on Rare-Earth Magnets and Their Applications, Pt. I, edited by Herget, C. and Poerschke, P. (Deutsche Physikalische Geselshaft, Bad Honnef, 1987) p. 355.
10. Tsubokawa, Y., Shimizu, R., Hirosawa, S. and Sagawa, M., in Microstructure-Property Relationships in Magnetic Materials, MRS Int'l. Mtg. on Adv. Mats. Vol.11, (Materials Research Society, Pittsburgh, PA, 1989) p. 75.
11. Sagawa, M. and Hirosawa, S., J. Mater. Res. 3, 45 (1988).
12. Kronmüller, H., in Microstructure-Property Relationships in Magnetic Materials, MRS. Int'l. Mtg. on Adv. Mats. Vol.11, (Materials Research Society, Pittsburgh, PA, 1989) p. 3; J. Magn. Soc. Jpn. 15(1), 6 (1991).
13. Matrinek, G. and Kronmfller, H., J. Magn. Magn. Materials, 69, 177 (1990).
14. Grönfeld, M. and Kronmüller, H., J. Magn. Magn. Materials 88, L267 (1990).
15. Yamamoto, H., Hirosawa, S., Fujimura, S., Tokuhara, K., Nagata, H., and Sagawa, M., IEEE Trans. Magn. MAG–23(5), 2100 (1987).
16. Fidler, J., Groiss, C. and Tokunaga, M., IEEE Trans. Magn. MAG–26, 1948 (1990).
17. Endoh, M., Tokunaga, M. and Harada, H., IEEE Trans. Magn. MAG–23, 2290 (1987).
18. Matsuura, Y., Hirosawa, S., Yamamoto, H., Fujimura, S., Sagawa, M. and Osamura, K., Jpn. J. Appl. Phys. 24, L635 (1985).
19. Hirosawa, S. and Tsubokawa, Y., J. Magn. Magn. Mater. 84, 309316 (1990).

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Relations of Corrosion Resistance, Coercivity, and Magnetizability of Modified Nd-Fe-B Sintered Magnets to Their Microstructure

  • Satoshi Hirosawa (a1), Koki Tokuhara (a1), Shuji Mino (a1), Toshiyuki Matsui (a2), Kenji Morii (a2) and Yutaka Nakayama (a2)...

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