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Explosive shock processing of Pr2Fe14B/α–Fe exchange-coupled nanocomposite bulk magnets

  • Z.Q. Jin (a1), N.N. Thadhani (a2), M. McGill (a2), Y. Ding (a2), Z.L. Wang (a2), M. Chen (a3), H. Zeng (a3), V.M. Chakka (a4) and J.P. Liu (a4)...


Explosive shock compaction was used to consolidate powders obtained from melt-spun Pr2Fe14B/α–Fe nanocomposite ribbons, to produce fully dense cylindrical compacts of 17–41-mm diameter and 120-mm length. Characterization of the compacts revealed refinement of the nanocomposite structure, with approximately 15 nm uniformly sized grains. The compact produced at a shock pressure of approximately 1 GPa maintained a high coercivity, and its remanent magnetization and maximum energy product were measured to be 0.98 T and 142 kJ/m3, respectively. The compact produced at 4–7 GPa showed a decrease in magnetic properties while that made at 12 GPa showed a magnetic softening behavior. However, in both of these cases, a smooth hysteresis loop implying exchange coupling and a coercivity of 533 kA/m were fully recovered after heat treatment. The results illustrate that the explosive compaction followed by post-shock heat treatment can be used to fabricate exchange-coupled nanocomposite bulk magnets with optimized magnetic properties.


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1.Wecker, J., Schnitzke, K., Cerva, H. and Grogger, W.: Nanostructured Nd–Fe–B magnets with enhanced remanence. App. Phys. Lett. 67, 563 (1995).
2.Coehoorn, R., de Mooij, D.B., Duchateau, J.P.W.B., and Buschow, K.H.J.: Novel permanent magnetic-materials made by rapid quenching. J. Phys. C 49, 669 (1988).
3.Kneller, E.F. and Hawig, R.: The exchange-spring magnet—A new material principle for permanent-magnets. IEEE Trans. Magn. 27, 3588 (1991).
4.Goll, D., Seeger, M. and Kronmüller, H.: Magnetic and microstructural properties of nanocrystalline exchange coupled PrFeB permanent magnets. J. Magn. Magn. Mater. 185, 49 (1998).
5.Wang, Z.C., Davies, H.A. and Harland, C.L.: Crystallization behavior and magnetic properties of melt-spun Prx(Fe0.8Co0.2)94−xB6 alloys. IEEE Trans. Magn. 38, 2967 (2002).
6.Liu, J.P., Luo, C.P., Liu, Y. and Sellmyer, D.J.: High energy products in rapidly annealed nanoscale Fe/Pt multilayers. Appl. Phys. Lett. 72, 483 (1998).
7.Zeng, H., Li, J., Liu, J.P., Wang, Z.L. and Sun, S.H.: Exchange-coupled nanocomposite magnets by nanoparticles self-assembly. Nature 420, 395 (2002).
8.Jin, Z.Q., Cui, B.Z., Liu, J.P., Ding, Y., Wang, Z.L. and Thadhani, N.N.: Controlling the crystallization and magnetic properties of melt-spun Pr2Fe14B/α–Fe nanocomposites. Appl. Phys. Lett. 84, 4382 (2004).
9.Guruswamy, S., McCarter, M.K., Shield, J.E. and Panchanathan, V.: Explosive compaction of magnequench Nd–Fe–B magnetic powders. J. Appl. Phys. 79, 4851 (1996).
10.Leonowicz, M., Kaszuwara, W., Lezierska, E., Januszewski, D., Mendoza, G., Davies, H.A. and Paszula, J.: Application of the shock compaction technique for consolidation of hard magnetic powders. J. Appl. Phys. 83, 6634 (1998).
11.Oda, H., Hirai, H., Kondo, K. and Sato, T.: Magnetic-properties of shock-compacted high-coercivity magnets with a nanometer-sized microstructure. J. Appl. Phys. 76, 3381 (1994).
12.Saito, T.: Production of bulk materials of an Nd4Fe77.5B18.5 alloy and their magnetic properties. IEEE Tran Magn. 37, 2561 (2001).
13.Gourdin, W.H.: Dynamic consolidation of metal powders. Prog. Mater. Sci. 31, 39 (1986).
14.Ando, S., Mine, Y., Takashima, K., Itoh, S. and Tonda, H.: Explosive compaction of Nd-Fe-B powder. J. Mater. Process. Technol. 85, 42 (1999).
15.Mashimo, T., Huang, X., Hirosawa, S., Makita, K., Kato, Y., Mitsudo, S. and Motokawa, M.: Magnetic properties of fully dense Sm2Fe17Nx magnets prepared by shock compression. J. Magn. Magn. Mater. 210, 109 (2000).
16.Jin, Z.Q., Chen, K.H., Li, J., Zeng, H., Cheng, S-F., Liu, J.P., Wang, Z.L. and Thadhani, N.N.: Shock compression response of magnetic nanocomposite powders. Acta Mater. 52, 2147 (2004).
17.Chen, K.H., Jin, Z.Q., Li, J., Kennedy, G., Wang, Z.L., Thadhani, N.N., Zeng, H., Cheng, S-F. and Liu, J.P.: Bulk nanocomposite magnets produced by dynamic shock compaction. J. Appl. Phys. 96, 1276 (2004).
18.Meyers, M.A. and Wang, S.L.: An improved method for shock consolidation of powders. Acta Metall. 36, 925 (1988).
19. AUTODYN-2D/2.8, Non-Linear dynamic modeling software (Century Dynamics Inc., Oakland, CA, 1995).
20.Hermann, W.: Constitutive equation for the dynamic compaction of ductile porous materials. J. Appl. Phys. 40, 2490 (1969).
21.Chau, R., Maple, M.B. and Nellis, W.J.: Shock compaction of SmCo5 particles. J. Appl. Phys. 79, 9236 (1996).
22.Jin, Z.Q., Okumura, H., Muñoz, J.S., Zhang, Y., Wang, H.L. and Hadjipanayis, G.C.: Multi-step crystallization evolution in nanocomposite Pr8Fe86B6 alloys. J. Phys. D: Appl. Phys. 35, 2893 (2002).
23.Shkuratov, S.I., Talantsev, E.F., Dickens, J.C., Kristiansen, M. and Baird, J.: Longitudinal-shock-wave compression of Nd2Fe14B high-energy hard ferromagnet: The pressure-induced magnetic phase transition. Appl. Phys. Lett. 82, 1248 (2003).
24.Meyers, M.A.: Dynamic Behavior of Materials (John Wiley & Sons, New York, 1994), p. 382.
25.Thadhani, N.N.: Shock-induced and shock-assisted solid-state chemical-reactions in powder mixtures. J. Appl. Phys. 76, 2129 (1994).
26.Li, J., Jin, Z.Q., Liu, J.P., Wang, Z.L. and Thadhani, N.N.: Amorphization and ultrafine-scale recrystallization in shear bands formed in shock-consolidated Pr2Fe14B/α–Fe nanocomposite magnets. Appl. Phys. Lett. 85, 2223 (2004).
27.Sun, X.K., Zhang, J., Chu, Y.L., Liu, W., Cui, B.Z. and Zhang, Z.D.: Dependence of magnetic properties on grain size of alpha-Fe in nanocomposite (Nd,Dy)(Fe,Co,Nb,B)5.5/α–Fe magnets. Appl. Phys. Lett. 74, 1740 (1999).
28.Kronmüller, H., Fischer, R., Seeger, M. and Zern, A.: Micromagnetism and microstructure of hard magnetic materials. J. Phys. D: Appl. Phys. 29, 2274 (1996).
29.Shkuratov, S.I., Talantsev, E.F., Dickens, J.C. and Kristiansen, M.: Transverse shock wave demagnetization of Nd2Fe14B high-energy hard ferromagnetics. J. Appl. Phys. 92, 159 (2003).
30.Chen, Z.H., Zhang, J.X. and Kronmüller, H.: Magnetically soft phase in magnetization reversal processes of nanocomposite Sm2Fe15Ga2Cx /α–Fe permanent magnetic materials. Phys. Rev. B 68, 144417 (2003).
31.Bauer, J., Seeger, M., Zern, A. and Kronmüller, H.: Nanocrystalline FeNdB permanent magnets with enhanced remanence. J. Appl. Phys. 80, 1667 (1996).
32.Gao, R.W., Feng, W.C., Liu, H.Q., Wang, B., Chen, W., Han, G.B., Zhang, P., Li, H., Li, W., Guo, Y.Q., Pan, W., Li, X.M., Zhu, M.G. and Li, X.: Exchange-coupling interaction, effective anisotropy and coercivity in nanocomposite permanent materials. J. App. Phys. 94, 664 (2003).
33.Moskowitz, B.M.: Micromagnetic study of the influence of crystal defects on coercivity in magnetite. J. Geophys. Res-Solid Earth. 98, 18011 (1993).
34.Abdelaal, M.M.: Magnetic-behavior of Y2Fe14−xTxB compounds, where T = Al, Ti, V, Cr, Mn, Co or Ni. J. Magn. Magn. Mater. 131, 148 (1994).



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