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Composite magnetic materials based on nanocrystalline powders for high-frequency applications
ARTICLE IN PRESS
Journal of Magnetism and Magnetic Materials 310 (2007) e864–e866 www.elsevier.com/locate/jmmm
Composite magnetic materials based on nanocrystalline powders for high-frequency applications Hongwei Qina, Jifan Hua,, Bo Lib, Minhua Jianga a
Department of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, PR China b Central Iron and Steel Research Institute, Beijing 100081, PR China Available online 27 November 2006
Abstract The composite cores were prepared by compacting milled powders of as-quenched nanocrystalline ribbons Fe–Cu–Nb–Si–B and Fe–Zr–B–Cu with epoxy resin. The real permeability at 1 MHz of Fe72Cu2.5Nb3Si13.5B9 powder core with 5 wt% epoxy resin is 30.9 when compacting under 24 MPa, and is 33.0 when compacting under 49 MPa. The powder cores prepared from as-quenched nanocrystalline ribbons show a flat permeability in a wide frequency range. The transition of permeability spectra from resonance to relaxation can be induced by enhancing the compacting pressure. r 2006 Elsevier B.V. All rights reserved. PACS: 75.50.k; 85.70 Keywords: Composite material; Powder core; Nanocrystalline; Permeability; High frequency
Previously, nanocrystalline Fe–Cu–Nb–Si–B and Fe–M–B (M ¼ Zr, Hf and Nb) were obtained by crystallization of amorphous ribbons through annealing processes [1,2]. Recently, we reported that nanocrystalline ribbons Fe–Cu–Nb–Si–B and Fe–Zr–B–Cu with high Cu contents, having high effective permeability, high saturation magnetic induction and low saturation magnetostriction, can be fabricated by melt-spinning technique without additional annealing [3]. An appropriate Cu addition improves the nucleation of a-Fe(Si) or a-Fe in as-quenched ribbons, similar to the case of annealed nanocrystalline [4]. The permeability of cores based on the powder flakes of annealed nanocrystalline Fe–Cu–Nb–Si–B was extensively studied, because of the stimulation of fabricating magnetic parts with complex shapes and designs [5,6]. This work reported on the permeability spectra of composite magnetic cores prepared by compacting milled powders of as-
Corresponding author. Tel.: +86 531 88566143; fax: +86 531 88565167. E-mail address: [email protected] (J. Hu).
0304-8853/$ - see front matter r 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jmmm.2006.11.023
quenched nanocrystalline ribbons Fe–Cu–Nb–Si–B and Fe–Zr–B–Cu with epoxy resin. The as-quenched nanocrystalline ribbons Fe72Cu2.5Nb3 Si13.5B9 and Fe87Zr7B3Cu3 were prepared by the single roller melt-spinning technique with the quenching speed of 40 m/s. Nanostructures and their soft magnetic properties were investigated previously [3]. The powders with size of 80–160 mm were obtained by milling as-quenched nanocrystalline ribbons in agate mortar and sieving, respectively. The powders were then mixed with different contents of epoxy resin. The mixed powders were compacted into cores under pressure of 24 and 49 MPa, respectively. The frequency spectra of complex permeability for the composite powder cores were measured by an impedance analyzer under HACE0.2 A/m at room temperature. The typical experimental frequency spectra of complex permeability for powder core based on as-quenched nanocrystalline Fe72Cu2.5Nb3Si13.5B9 with 5 wt% epoxy resin compacted under 24 Mpa, are shown in Fig. 1. The real permeability m0 at 1 MHz is 30.9. For Fe72Cu2.5Nb3 Si13.5B9 powder cores with 10 and 15 wt% epoxy resin
ARTICLE IN PRESS H. Qin et al. / Journal of Magnetism and Magnetic Materials 310 (2007) e864–e866
Fig. 1. Experimental and calculated frequency spectra of complex permeability for Fe72Cu2.5Nb3Si13.5B9 powder core with 5 wt% epoxy resin compacted under 24 MPa.
compacted under 24 MPa, the value of m0 at 1 MHz was measured at 20.9 and 16.8, respectively. The permeability of composite powder cores drops sharply with an increase of epoxy resin content. It can also be seen from Fig. 2 that the real permeability m0 at 1 MHz is 14.3 for powder cores Fe87Zr7B3Cu3. The variation of real permeability m0 from 1 to 10 MHz is 1.3% for Fe72Cu2.5Nb3Si13.5B9 core, and is 7.7% for Fe87Zr7B3Cu3 core, when compacting under 24 MPa with 5 wt% epoxy resin. A resonance spectra of complex permeability occurs for cores Fe72Cu2.5Nb3Si13.5B9 and Fe87Zr7B3Cu3 compacted under 24 MPa, as shown in Figs. 1 and 2. Such resonant permeability spectra can be well described by the equations of domain wall dispersion [7,8]: 2 1 oo0 m0 1 ¼ wi (1) 2 2 2 o o 1 o0 þ or o or
m00 ¼ wi 1
2 2 o o0
þ
2
(2)
o or
where wi is the static initial susceptibility, o0 ¼ (a/mw)1/2 is domain wall resonance frequency, or ¼ a/b is relaxation frequency, mw is effective domain wall mass, a is the spring constant, b is the damping factor. The calculated permeability spectra and the corresponding parameters of wi, f0 ¼ o0/2p and fr ¼ or/2p for powder cores compacted under 24 MPa were presented in Figs. 1 and 2. According to domain wall dynamics [7–9], we derived values of mw ¼ 2.63 1010 kg/m2, a ¼ 1.44 107, b ¼ 0.030 for nanocrystalline core Fe72Cu2.5Nb3Si13.5B9, and mw ¼ 3.24 1010 kg/m2, a ¼ 3.66 107, b ¼ 0.053 for nanocrystalline core Fe87Zr7B3Cu3 when compacting under 24 MPa with 5 wt% epoxy resin, respectively. Fig. 3 shows the experimental frequency spectra of complex permeability for Fe72Cu2.5Nb3Si13.5B9 powder
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Fig. 2. Experimental and calculated frequency spectra of complex permeability for Fe87Zr7B3Cu3 powder core compacted under 24 MPa with 5 wt% epoxy resin.
Fig. 3. Experimental frequency spectra of complex permeability for Fe72Cu2.5Nb3Si13.5B9 powder core compacted under 49 MPa with 5 wt% epoxy resin.
core compacted under 49 MPa with 5 wt% epoxy resin. The relaxation permeability spectra can be observed. The real permeability m0 is 36.1 and 33.0 at 50 kHz and 1 MHz, respectively. The variation of real permeability from 50 kHz to 1 MHz is 8.6%. The transition of permeability spectra from resonance to relaxation can be induced by enhancing the applied pressure in powder compaction, which reduces the holes among particles and inter-particle resistance, enhancing the eddy current effect. For Fe72Cu2.5Nb3Si13.5B9 powder cores with 5 wt% epoxy resin, the value of relaxation frequency fr when compacting under 49 MPa can be estimated as 70 MHz (see Fig. 3), smaller than the value of fr (76 MHz) when compacting under 24 MPa (see Fig. 1). This work was supported by National Natural Science Foundation of China. References [1] Y. Yoshizawa, S. Oguma, K. Yamauchi, J. Appl. Phys. 64 (1988) 6044. [2] K. Suzuki, N. Kataoka, A. Inoue, A. Makino, T. Masumoto, Mater. Trans. 31 (1990) 743.
ARTICLE IN PRESS e866
H. Qin et al. / Journal of Magnetism and Magnetic Materials 310 (2007) e864–e866
[3] J.F. Hu, B. Li, H.W. Qin, M.H. Jiang, IEEE Trans. Magn. 41 (2005) 3268. [4] K. Hono, K. Hiraga, Q. Wang, A. Inoue, T. Sakurai, Surf. Sci. 266 (1992) 385. [5] V. Le´ger, C. Ramiarinjaona, R. Barrue´, R. Lebourgeois, J. Magn. Magn. Mater. 191 (1999) 169.
[6] D. Nuetzel, G. Rieger, J. Wecker, J. Petzold, M. Mueller, J. Magn. Magn. Mater. 196–197 (1999) 327. [7] W. Do¨ring, Z. Naturforsch. 3a (1948) 373. [8] R. Becker, J. Phys. Radium 12 (1951) 332. [9] Y.C. Guo, Ferromagnetism, Education Publisher, Beijing, 1965.
Journal of Magnetism and Magnetic Materials 310 (2007) e864–e866 www.elsevier.com/locate/jmmm
Composite magnetic materials based on nanocrystalline powders for high-frequency applications Hongwei Qina, Jifan Hua,, Bo Lib, Minhua Jianga a
Department of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, PR China b Central Iron and Steel Research Institute, Beijing 100081, PR China Available online 27 November 2006
Abstract The composite cores were prepared by compacting milled powders of as-quenched nanocrystalline ribbons Fe–Cu–Nb–Si–B and Fe–Zr–B–Cu with epoxy resin. The real permeability at 1 MHz of Fe72Cu2.5Nb3Si13.5B9 powder core with 5 wt% epoxy resin is 30.9 when compacting under 24 MPa, and is 33.0 when compacting under 49 MPa. The powder cores prepared from as-quenched nanocrystalline ribbons show a flat permeability in a wide frequency range. The transition of permeability spectra from resonance to relaxation can be induced by enhancing the compacting pressure. r 2006 Elsevier B.V. All rights reserved. PACS: 75.50.k; 85.70 Keywords: Composite material; Powder core; Nanocrystalline; Permeability; High frequency
Previously, nanocrystalline Fe–Cu–Nb–Si–B and Fe–M–B (M ¼ Zr, Hf and Nb) were obtained by crystallization of amorphous ribbons through annealing processes [1,2]. Recently, we reported that nanocrystalline ribbons Fe–Cu–Nb–Si–B and Fe–Zr–B–Cu with high Cu contents, having high effective permeability, high saturation magnetic induction and low saturation magnetostriction, can be fabricated by melt-spinning technique without additional annealing [3]. An appropriate Cu addition improves the nucleation of a-Fe(Si) or a-Fe in as-quenched ribbons, similar to the case of annealed nanocrystalline [4]. The permeability of cores based on the powder flakes of annealed nanocrystalline Fe–Cu–Nb–Si–B was extensively studied, because of the stimulation of fabricating magnetic parts with complex shapes and designs [5,6]. This work reported on the permeability spectra of composite magnetic cores prepared by compacting milled powders of as-
Corresponding author. Tel.: +86 531 88566143; fax: +86 531 88565167. E-mail address: [email protected] (J. Hu).
0304-8853/$ - see front matter r 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jmmm.2006.11.023
quenched nanocrystalline ribbons Fe–Cu–Nb–Si–B and Fe–Zr–B–Cu with epoxy resin. The as-quenched nanocrystalline ribbons Fe72Cu2.5Nb3 Si13.5B9 and Fe87Zr7B3Cu3 were prepared by the single roller melt-spinning technique with the quenching speed of 40 m/s. Nanostructures and their soft magnetic properties were investigated previously [3]. The powders with size of 80–160 mm were obtained by milling as-quenched nanocrystalline ribbons in agate mortar and sieving, respectively. The powders were then mixed with different contents of epoxy resin. The mixed powders were compacted into cores under pressure of 24 and 49 MPa, respectively. The frequency spectra of complex permeability for the composite powder cores were measured by an impedance analyzer under HACE0.2 A/m at room temperature. The typical experimental frequency spectra of complex permeability for powder core based on as-quenched nanocrystalline Fe72Cu2.5Nb3Si13.5B9 with 5 wt% epoxy resin compacted under 24 Mpa, are shown in Fig. 1. The real permeability m0 at 1 MHz is 30.9. For Fe72Cu2.5Nb3 Si13.5B9 powder cores with 10 and 15 wt% epoxy resin
ARTICLE IN PRESS H. Qin et al. / Journal of Magnetism and Magnetic Materials 310 (2007) e864–e866
Fig. 1. Experimental and calculated frequency spectra of complex permeability for Fe72Cu2.5Nb3Si13.5B9 powder core with 5 wt% epoxy resin compacted under 24 MPa.
compacted under 24 MPa, the value of m0 at 1 MHz was measured at 20.9 and 16.8, respectively. The permeability of composite powder cores drops sharply with an increase of epoxy resin content. It can also be seen from Fig. 2 that the real permeability m0 at 1 MHz is 14.3 for powder cores Fe87Zr7B3Cu3. The variation of real permeability m0 from 1 to 10 MHz is 1.3% for Fe72Cu2.5Nb3Si13.5B9 core, and is 7.7% for Fe87Zr7B3Cu3 core, when compacting under 24 MPa with 5 wt% epoxy resin. A resonance spectra of complex permeability occurs for cores Fe72Cu2.5Nb3Si13.5B9 and Fe87Zr7B3Cu3 compacted under 24 MPa, as shown in Figs. 1 and 2. Such resonant permeability spectra can be well described by the equations of domain wall dispersion [7,8]: 2 1 oo0 m0 1 ¼ wi (1) 2 2 2 o o 1 o0 þ or o or
m00 ¼ wi 1
2 2 o o0
þ
2
(2)
o or
where wi is the static initial susceptibility, o0 ¼ (a/mw)1/2 is domain wall resonance frequency, or ¼ a/b is relaxation frequency, mw is effective domain wall mass, a is the spring constant, b is the damping factor. The calculated permeability spectra and the corresponding parameters of wi, f0 ¼ o0/2p and fr ¼ or/2p for powder cores compacted under 24 MPa were presented in Figs. 1 and 2. According to domain wall dynamics [7–9], we derived values of mw ¼ 2.63 1010 kg/m2, a ¼ 1.44 107, b ¼ 0.030 for nanocrystalline core Fe72Cu2.5Nb3Si13.5B9, and mw ¼ 3.24 1010 kg/m2, a ¼ 3.66 107, b ¼ 0.053 for nanocrystalline core Fe87Zr7B3Cu3 when compacting under 24 MPa with 5 wt% epoxy resin, respectively. Fig. 3 shows the experimental frequency spectra of complex permeability for Fe72Cu2.5Nb3Si13.5B9 powder
e865
Fig. 2. Experimental and calculated frequency spectra of complex permeability for Fe87Zr7B3Cu3 powder core compacted under 24 MPa with 5 wt% epoxy resin.
Fig. 3. Experimental frequency spectra of complex permeability for Fe72Cu2.5Nb3Si13.5B9 powder core compacted under 49 MPa with 5 wt% epoxy resin.
core compacted under 49 MPa with 5 wt% epoxy resin. The relaxation permeability spectra can be observed. The real permeability m0 is 36.1 and 33.0 at 50 kHz and 1 MHz, respectively. The variation of real permeability from 50 kHz to 1 MHz is 8.6%. The transition of permeability spectra from resonance to relaxation can be induced by enhancing the applied pressure in powder compaction, which reduces the holes among particles and inter-particle resistance, enhancing the eddy current effect. For Fe72Cu2.5Nb3Si13.5B9 powder cores with 5 wt% epoxy resin, the value of relaxation frequency fr when compacting under 49 MPa can be estimated as 70 MHz (see Fig. 3), smaller than the value of fr (76 MHz) when compacting under 24 MPa (see Fig. 1). This work was supported by National Natural Science Foundation of China. References [1] Y. Yoshizawa, S. Oguma, K. Yamauchi, J. Appl. Phys. 64 (1988) 6044. [2] K. Suzuki, N. Kataoka, A. Inoue, A. Makino, T. Masumoto, Mater. Trans. 31 (1990) 743.
ARTICLE IN PRESS e866
H. Qin et al. / Journal of Magnetism and Magnetic Materials 310 (2007) e864–e866
[3] J.F. Hu, B. Li, H.W. Qin, M.H. Jiang, IEEE Trans. Magn. 41 (2005) 3268. [4] K. Hono, K. Hiraga, Q. Wang, A. Inoue, T. Sakurai, Surf. Sci. 266 (1992) 385. [5] V. Le´ger, C. Ramiarinjaona, R. Barrue´, R. Lebourgeois, J. Magn. Magn. Mater. 191 (1999) 169.
[6] D. Nuetzel, G. Rieger, J. Wecker, J. Petzold, M. Mueller, J. Magn. Magn. Mater. 196–197 (1999) 327. [7] W. Do¨ring, Z. Naturforsch. 3a (1948) 373. [8] R. Becker, J. Phys. Radium 12 (1951) 332. [9] Y.C. Guo, Ferromagnetism, Education Publisher, Beijing, 1965.