Amorphous alloy soft magnetic powder, compacted magnetic core, magnetic element, and electronic equipment

Abstract

To provide amorphous alloy soft magnetic powder having both high magnetic permeability and low coercive force, a powder magnetic core containing the amorphous alloy soft magnetic powder and a magnetic element, and an electronic device capable of achieving high output.SOLUTION: Amorphous alloy soft magnetic powder is constituted of particles having a composition with a compositional formula Fea(Si1-xBx)bCc represented by ratios of the number of atoms [provided that a, b, c and x satisfy 76.0≤a≤81.0, 16.0≤b≤22.0, 0<c≤3.0 and 0.5≤x≤0.9]. When XAFS measurement is performed with an analysis depth set to a surface, an obtained Si-K absorption edge XANES spectrum has a peak A having an energy in a range of 1,845±1 eV and a peak B having an energy in a range of 1,848±1 eV, and an intensity ratio A / B is 0.25 or less where A is an intensity of the peak A and B is an intensity of the peak B.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to amorphous alloy soft magnetic powder, compacted magnetic cores, magnetic elements, and electronic devices.

Background Art

[0002] In Patent Document 1, there is disclosed a soft magnetic alloy powder having a main component composed of a composition formula (Fe X1 α X2 β ), (1-(a+b+c+d+e+f)) M a B b P c Si d C e S f where X1 is one or more selected from the group consisting of Co and Ni, X2 is one or more selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O, and rare earth elements, M is one or more selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W, Ti, and V, 0 ≦ a ≦ 0.160, 0.020 ≦ b ≦ 0.200, 0 ≦ c ≦ 0.150, 0 ≦ d ≦ 0.060, 0 ≦ e ≦ 0.030, 0.0010 ≦ f ≦ 0.030, 0.005 ≦ f / b ≦ 1.50, α ≧ 0, β ≧ 0, and 0 ≦ α + β ≦ 0.50. And it is disclosed that according to such a configuration, a soft magnetic alloy powder excellent in soft magnetic properties and having a low coercive force can be obtained. [[ID=​​​​​​​​​​​​​​​​​​​​

[0005] However, in terms of achieving both high magnetic permeability and low coercive force, the soft magnetic alloy powder described in Patent Document 1 still has room for improvement. Specifically, when attempting to increase the magnetic permeability in soft magnetic powder, it tends to become difficult to sufficiently reduce the coercive force. Therefore, it has been an issue to realize soft magnetic powder that achieves both high magnetic permeability and low coercive force.

Means for Solving the Problem

[0006] The amorphous alloy soft magnetic powder according to an application example of the present invention is composed of particles having a composition formula Fe a (Si 1-x B x ) b C c [where a, b, c, and x satisfy 76.0 ≦ a ≦ 81.0, 16.0 ≦ b ≦ 22.0, 0 < c ≦ 3.0, and 0.5 ≦ x ≦ 0.9.] and when XAFS measurement is performed on the particles with the analysis depth set to the surface, the obtained Si-K absorption edge XANES spectrum has a peak A existing within the energy range of 1845 ± 1 eV and a peak B existing within the energy range of 1848 ± 1 eV, and when the intensity of the peak A is A and the intensity of the peak B is B, the intensity ratio A / B is as follows. 0.12 or higher, 0.23

[0007] The compacted magnetic core according to an application example of the present invention contains the amorphous alloy soft magnetic powder according to an application example of the present invention.

[0008] The magnetic element according to an application example of the present invention includes the compacted magnetic core according to an application example of the present invention. ​​

[0009] The electronic device according to an example of the application of the present invention is The present invention comprises a magnetic element according to an example of its application. [Brief explanation of the drawing]

[0010] [Figure 1] This is a longitudinal cross-sectional view showing an example of an apparatus for producing amorphous alloy soft magnetic powder by the rotary water atomization method. [Figure 2] This is a schematic plan view showing a toroidal coil component. [Figure 3] This is a schematic, transmissive perspective view showing a closed-magnetic-circuit type coil component. [Figure 4] This is a perspective view showing a mobile personal computer, which is an electronic device equipped with a magnetic element according to the embodiment. [Figure 5] This is a plan view showing a smartphone, which is an electronic device equipped with a magnetic element according to the embodiment. [Figure 6] This is a perspective view showing a digital still camera, which is an electronic device equipped with a magnetic element according to an embodiment. [Figure 7] These are the Si-K absorption edge XANES spectra obtained for amorphous alloy soft magnetic powders of Sample No. 1 (Example) and Sample No. 9 (Comparative Example), with the analysis depth set to the surface. [Figure 8] This shows the radial distribution function based on the Fe-K absorption edge EXAFS spectra obtained by setting the analysis depth to bulk for amorphous alloy soft magnetic powders of Sample No. 1 (Example) and Sample No. 9 (Comparative Example). [Figure 9] The X-ray diffraction profiles obtained using an X-ray diffractometer for amorphous alloy soft magnetic powders of Sample No. 1 (Example) and Sample No. 9 (Comparative Example) are shown. [Modes for carrying out the invention]

[0011] Hereinafter, the amorphous alloy soft magnetic powder, compacted powder core, magnetic element, and electronic device of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

[0012] 1. Amorphous Alloy Soft Magnetic Powder The amorphous alloy soft magnetic powder according to the embodiment is an amorphous alloy powder exhibiting soft magnetism. The amorphous alloy soft magnetic powder can be applied to any use, and for example, it is formed by binding particles together. Thereby, a compacted powder core used for a magnetic element is obtained.

[0013] The amorphous alloy soft magnetic powder according to the embodiment has a composition formula Fe a (Si 1-x B x ) b C c [However, a, b, c, and x are such that 76.0 ≤ a ≤ 81.0, 16.0 ≤ b ≤ 22.0, 0 < c ≤ 3.0, and 0.5 ≤ x ≤ 0.9.] and is a powder composed of particles having such a composition.

[0014] When XAFS measurement is performed by setting the analysis depth for the particles to the bulk, the obtained Si-K absorption edge XANES spectrum has a peak A existing within the energy range of 1845 ± 1 eV and a peak B existing within the energy range of 1848 ± 1 eV. And when the intensity of peak A is A and the intensity of peak B is B, the intensity ratio A / B is 0.25 or less.

[0015] Such amorphous alloy soft magnetic powder achieves both high magnetic permeability and low coercive force. Therefore, by using such amorphous alloy soft magnetic powder, miniaturization and high output of magnetic elements can be achieved.

[0016] 1.1. Composition Hereinafter, the composition of the amorphous alloy soft magnetic powder will be described in detail. As described above, the amorphous alloy soft magnetic powder according to the embodiment has a composition formula Fe a (Si 1-x B x )b C c It has a composition represented by the formula shown. This compositional formula represents the ratio of atoms in a composition consisting of four elements: Fe, Si, B, and C.

[0017] Fe (iron) significantly affects the basic magnetic and mechanical properties of the amorphous alloy soft magnetic powder according to this embodiment.

[0018] The Fe content is not particularly limited, but it is set so that Fe is the main component, i.e., the proportion of Fe atoms is the highest, in the amorphous alloy soft magnetic powder.

[0019] 'a' represents the ratio of Fe atoms, and is between 76.0 ≤ a ≤ 81.0, preferably 77.0 ≤ a ≤ 80.0, and more preferably 78.0 ≤ a ≤ 80.0. If 'a' falls below the lower limit, the magnetic properties or corrosion resistance may decrease. On the other hand, if 'a' exceeds the upper limit, crystallization may occur more easily during the production of amorphous alloy soft magnetic powder.

[0020] Silicon (Si) promotes the amorphization process when manufacturing amorphous alloy soft magnetic powder from raw materials, and also increases the permeability of the amorphous alloy soft magnetic powder. This makes it possible to achieve high permeability and low coercivity.

[0021] Boron (B) promotes amorphous formation when manufacturing amorphous alloy soft magnetic powder from raw materials. In particular, using Si and B together can synergistically promote amorphous formation based on the difference in their atomic radii. This allows for sufficient improvement in magnetic permeability and low coercivity.

[0022] x represents the ratio of the number of B atoms to the total number of Si atoms, with the sum of the number of Si atoms and B atoms being 1. In the amorphous alloy soft magnetic powder according to this embodiment, x is 0.5 ≤ x ≤ 0.9, but preferably 0.6 ≤ x ≤ 0.8. This allows for the optimization of the balance between the number of Si atoms and the number of B atoms. If x falls below the lower limit or exceeds the upper limit, the balance between the number of Si atoms and the number of B atoms will be disrupted, making it difficult to amorphize the powder, for example, when trying to improve magnetic properties by increasing the proportion of Fe.

[0023] b represents the ratio of the total amount of Si and B, and is 16.0 ≤ b ≤ 22.0, preferably 17.0 ≤ b ≤ 21.0, and more preferably 18.0 ≤ b ≤ 20.0. If b falls below the lower limit or exceeds the upper limit, crystallization is more likely to occur during the production of amorphous alloy soft magnetic powder.

[0024] The Si content is preferably 3.0 atomic% to 8.0 atomic%, and more preferably 5.0 atomic% to 7.0 atomic%.

[0025] The content of B is preferably 10.0 atomic% to 15.5 atomic%, and more preferably 12.5 atomic% to 14.5 atomic%.

[0026] When the raw materials for amorphous alloy soft magnetic powder are melted, carbon (C) reduces the viscosity of the molten material, facilitating amorphous and fine powder formation. This makes it possible to obtain amorphous alloy soft magnetic powder with small diameter and high magnetic permeability. As a result, eddy current losses can be suppressed even in the high-frequency range.

[0027] c represents the content of C, where 0 < c ≤ 3.0, preferably 1.0 ≤ c ≤ 2.8, and more preferably 1.5 ≤ c ≤ 2.5. When c is below the lower limit value, the viscosity of the melt does not decrease sufficiently, and the shape of the particles becomes irregular. Therefore, the filling property during powder compacting decreases, and the saturation magnetic flux density and magnetic permeability of the powder compact cannot be increased sufficiently. On the other hand, when c exceeds the upper limit value, it becomes easier to crystallize during the production of the amorphous alloy soft magnetic powder.

[0028] The amorphous alloy soft magnetic powder according to the embodiment has the above composition formula Fe a (Si 1-x B x ) b C c In addition to the composition represented by, it may contain trace amounts of additive elements. Examples of the trace amounts of additive elements include S (sulfur), P (phosphorus), etc. By including these, the viscosity of the melt can be particularly decreased. As a result, the spheroidization of the particles can be achieved, and the filling property can be enhanced. Also, these elements are semi-metallic elements and contribute to the improvement of the amorphous forming ability. Therefore, by including these additive elements, it becomes easier to obtain an amorphous alloy soft magnetic powder having a spectrum with the above-described characteristics. Such an amorphous alloy soft magnetic powder will have a high degree of amorphousness even when the Fe content is high, and can achieve both a high magnetic permeability and a low coercive force.

[0029] The content of S is not particularly limited, but it is preferably 0.0010 mass% or more and 0.0100 mass% or less, more preferably 0.0015 mass% or more and 0.0080 mass% or less, and even more preferably 0.0020 mass% or more and 0.0070 mass% or less. When the content of S is below the lower limit value, the effects such as the promotion of spheroidization and the improvement of the amorphous forming ability may not be obtained sufficiently. On the other hand, when the content of S exceeds the upper limit value, the addition amount becomes excessive, and there is a possibility of inhibiting the promotion of spheroidization and the improvement of the amorphous forming ability.

[0030] The P content is not particularly limited, but is preferably 0.0010% by mass or more and 0.0200% by mass or less, more preferably 0.0015% by mass or more and 0.0180% by mass or less, and even more preferably 0.0050% by mass or more and 0.0150% by mass or less. If the P content falls below the lower limit, the effects of promoting spheroidization and improving amorphous formation ability may not be sufficiently obtained. On the other hand, if the P content exceeds the upper limit, the amount added may be excessive, which may inhibit the promotion of spheroidization and improvement of amorphous formation ability.

[0031] Furthermore, by adding both S and P, the amorphous formation ability can be particularly enhanced. In this case, the ratio of S content to P content, S / P, is preferably 0.2 to 0.8, and more preferably 0.3 to 0.6. By setting S / P within the above range, it is possible to promote spheroidization and improve amorphous formation ability while suppressing the individual content of S and P. In other words, by suppressing the individual content, it is possible to suppress the decrease in the magnetic properties of the amorphous alloy soft magnetic powder, while at the same time suppressing the decrease in the degree of amorphization.

[0032] Furthermore, the amorphous alloy soft magnetic powder according to the embodiment may contain other elements in addition to the elements described above, whether as additives or impurities. The total content of these other elements is preferably 1.0% by mass or less, more preferably 0.2% by mass or less, and even more preferably 0.1% by mass or less. Within this range, the effects of the present invention are unlikely to be hindered by these other elements, so their inclusion is acceptable.

[0033] The composition of the amorphous alloy soft magnetic powder according to the embodiment has been described in detail above, but the above composition and impurities can be identified by the following analytical methods.

[0034] Examples of analytical methods include atomic absorption spectrometry for iron and steel as specified in JIS G 1257:2000, ICP emission spectrometry for iron and steel as specified in JIS G 1258:2007, spark discharge emission spectrometry for iron and steel as specified in JIS G 1253:2002, X-ray fluorescence spectrometry for iron and steel as specified in JIS G 1256:1997, and gravimetric titration-absorbance spectrophotometric methods as specified in JIS G 1211 to G 1237.

[0035] Specifically, examples include solid-state emission spectrometers manufactured by SPECTRO, particularly spark discharge emission spectrometers, model: SPECTROLAB, type: LAVMB08A, and the ICP instrument CIROS120 manufactured by Rigaku Corporation.

[0036] Furthermore, in particular, when identifying C (carbon) and S (sulfur), the oxygen-flow combustion (high-frequency induction heating furnace combustion)-infrared absorption method specified in JIS G 1211:2011 is also used. Specifically, the LECO CS-200 carbon-sulfur analyzer is an example.

[0037] Furthermore, when specifically identifying N (nitrogen) and O (oxygen), the methods for determining nitrogen in iron and steel as specified in JIS G 1228:1997 and the general rules for determining oxygen in metallic materials as specified in JIS Z 2613:2006 are also used. Specifically, the LECO TC-300 / EF-300 oxygen / nitrogen analyzer is an example.

[0038] 1.2. Evaluation of powder by XAFS measurement XAFS measurements are performed on particles constituting the amorphous alloy soft magnetic powder according to the embodiment, and X-ray absorption spectra are obtained. XAFS measurement is an X-ray absorption fine structure measurement, an analytical technique that investigates the chemical state and local structure of elements contained in particles based on the X-ray absorption specific to each element. XAFS measurements can obtain XANES (X-ray Absorption Near Edge Structure) spectra and EXAFS (Extended X-ray Absorption Fine Structure) spectra. From the XANES spectrum, mainly the chemical state (electronic state), such as the valence of the absorbing atom, can be obtained. From the EXAFS spectrum, mainly the local structure (coordination environment) around the absorbing atom can be obtained.

[0039] 1.2.1. Features (1) When XAFS measurements are performed on particles with the analysis depth set to the surface, the obtained Si-K absorption edge XANES spectrum has the characteristic (1) of having peak A and peak B. Peak A is a peak whose energy is in the range of 1845±1eV. Peak B is a peak whose energy is in the range of 1848±1eV. When the intensity of peak A is denoted as A and the intensity of peak B is denoted as B, the intensity ratio A / B is set to 0.25 or less, but is preferably 0.22 or less, and more preferably 0.20 or less.

[0040] Peak A represents a structure attributed to the Fe-Si atom pair. Peak B represents a structure attributed to SiO2. The fact that the intensity ratio A / B is within the aforementioned range means that the intensity ratio of the peaks attributed to the Fe-Si coordination, which represents the crystalline state, is low. Therefore, satisfying characteristic (1) indicates a high degree of amorphousness in the particles. Such amorphous alloy soft magnetic powders have a high degree of amorphousness even with a high Fe content, and can achieve both high permeability and low coercivity.

[0041] Furthermore, if the intensity ratio A / B exceeds the upper limit, the intensity ratio of the peaks attributed to Fe-Si coordination increases, resulting in a decrease in the degree of amorphization. In addition, while a lower limit for the intensity ratio A / B does not need to be set, it is preferable to set it to 0.05 or higher, and more preferably to 0.10 or higher, from the viewpoint of suppressing variations between particles.

[0042] Furthermore, the Si-K absorption edge XANES spectrum mentioned above is obtained by setting the analysis depth for the particle to the surface, as previously stated. Specifically, when X-rays are selected as the signal to be detected, the measurement depth can be set to the bulk (depth of several tens of μm), and when electrons are selected as the signal to be detected, the measurement depth can be set to the surface.

[0043] Furthermore, in this specification, "peak intensity" of a XANES spectrum refers to the height of the peak in the XANES spectrum from the pre-edge line. The pre-edge line in a XANES spectrum is defined as a straight line passing through data points at -150 eV and -30 eV relative to the absorption edge position of each peak. The absorption edge position refers to the position of the inflection point located on the lowest energy side of the absorption edge structure where the XANES spectrum rises sharply. In other words, it is the position of the maximum point of the first derivative of the XANES spectrum that is on the lowest energy side of the absorption edge structure.

[0044] In this specification, "peak" includes not only clearly convex shapes with a vertex, but also shapes that are not convex, such as shoulder structures. Furthermore, if neither a convex shape nor a shoulder structure exists, the maximum intensity within the specified range will be considered as the intensity of each peak.

[0045] 1.2.2. Characteristics (2) When XAFS measurements are performed on particles with the analysis depth set to bulk, the radial distribution function obtained by Fourier transforming the resulting Fe-K absorption edge EXAFS spectrum preferably has peak C and peak D as characteristic (2).

[0046] Peak C is a peak located within the range of interatomic distance between 0.10 nm and 0.14 nm. Peak D is a peak located within the range of interatomic distance between 0.19 nm and 0.23 nm. When the intensity of peak C is denoted as C and the intensity of peak D as D, the intensity ratio C / D is preferably 0.5 or less, more preferably between 0.05 and 0.4, and even more preferably between 0.1 and 0.3.

[0047] Peak C is a structure attributed to an oxygen atom adjacent to the absorbing Fe atom (first nearest neighbor oxygen atom). Peak D is a structure attributed to an iron atom adjacent to the absorbing Fe atom (first nearest neighbor Fe atom), or to an iron atom adjacent to the absorbing Fe atom (first nearest neighbor Si atom).

[0048] The fact that the intensity ratio C / D is within the aforementioned range indicates that the number of Fe-O atomic pairs derived from Fe oxides is relatively small compared to Fe-Si atomic pairs and Fe-Fe atomic pairs. This is thought to support the idea that there are fewer Fe oxides, making it easier for amorphization to be inhibited. Therefore, particles that satisfy characteristic (2) will have a high degree of amorphization even with a high Fe content, and can achieve both high permeability and low coercivity. Furthermore, since the radial distribution function having characteristic (2) was obtained by setting the analysis depth to bulk, it is thought to support the idea that the particles as a whole have a high degree of amorphization.

[0049] 1.2.3. Features (3) Among the radial distribution functions having characteristic (2), the maximum value in the range where the interatomic distance is less than 0.25 nm is denoted as E, and the maximum value in the range where the interatomic distance is 0.25 nm or more is denoted as F. In this case, the intensity ratio F / E is preferably 0.5 or less, more preferably 0.05 or more and 0.4 or less, and even more preferably 0.1 or more and 0.3 or less.

[0050] The fact that the intensity ratio F / E is within the aforementioned range indicates that the structure attributed to the second nearest neighbor Fe atom does not have a clear peak compared to the first nearest neighbor atom. This is thought to support the idea that the arrangement of atoms beyond the second nearest neighbor is random, that is, there is short-range order but no long-range order. Therefore, particles satisfying characteristic (3) will have a high degree of amorphousness even with a high Fe content, and can achieve both high permeability and low coercivity. In this specification, "maximum value" refers to the maximum intensity within a predetermined range.

[0051] 1.3. XAFS Measurement Method XAFS measurements can be performed under the following conditions.

[0052] • Measurement facility: Aichi Synchrotron Radiation Center • Acceleration energy: 1.2 GeV • Accumulated current value: 300mA • Monochromatization conditions: White X-rays from a bending magnet are monochromatized using a two-crystal spectrometer and used for measurement. • Beamline (BL) and measurement area used: BL5S1 • Angle of incidence on the sample: 15° (The above angle of incidence is the angle of incidence of X-rays relative to the normal to the sample surface.) • Energy calibration: Before performing XAFS measurements, transmission measurements are performed on an Fe-foil (reference sample) to calibrate the energy axis. • Measurement method: Simultaneous measurement of converted electron yield (CEY) and partial fluorescence yield (PFY) • Measurement preparation: Introduce the He gas into the atmospheric pressure chamber and purge with He gas for approximately 30 minutes before measurement. • I0 measurement method: Au-mesh

[0053] • Data processing to obtain the radial distribution function: XAFS spectral data is acquired using the QuickXAFS method. Background noise is subtracted from the obtained XAFS spectral data using a standard method. The K absorption edge energy E0 (x-axis) of each spectrum is defined as the energy value (x-axis) at which the first derivative is maximized in the spectrum near the K absorption edge of the X-ray absorption spectrum. Next, a baseline with an intensity axis of zero is set with the absorption edge energy E0 as the origin, for example, such that the average intensity in the range of -150eV to -30eV is zero. A baseline with an intensity axis of 1 is also set so that the average intensity in the range of +150eV to +450eV is 1. Subsequently, the waveform is adjusted using these two baselines.

[0054] Next, from the X-ray absorption spectra prepared as described above, the EXAFS spectra of the K absorption edge of Si and Fe, as well as the radial distribution function, are obtained as follows. First, the EXAFS oscillations are analyzed on the prepared X-ray absorption spectrum data using the EXAFS analysis software Athena. For each spectrum, the absorbance (μ0) of isolated atoms is estimated by the Spline Smoothing method, and the EXAFS function χ(k) is extracted. Finally, k 3 EXAFS function k weighted by 3 For χ(k), for example, k ranges from 3.0 to 12.0 Å. -1 Perform a Fourier transform within this range. This will give you the radial distribution function.

[0055] 1.4. Other characteristics The degree of amorphousness in amorphous alloy soft magnetic powder can be determined based on the degree of crystallinity. The degree of crystallinity in amorphous alloy soft magnetic powder is calculated from the spectrum obtained by X-ray diffraction of the amorphous alloy soft magnetic powder based on the following formula. Crystallinity = {Crystal-derived strength / (Crystal-derived strength + Amorphous-derived strength)} × 100

[0056] Furthermore, as an X-ray diffractometer, for example, the RINT2500V / PC manufactured by Rigaku Corporation is used.

[0057] The degree of crystallinity measured by this method is preferably 70% or less, and more preferably 60% or less. This makes the improvement in soft magnetism associated with amorphousness more pronounced. As a result, an amorphous alloy soft magnetic powder with sufficiently low coercivity is obtained. In other words, it is preferable that the amorphous alloy soft magnetic powder is entirely amorphous, but it may contain crystalline structures in a volume ratio of, for example, 70% or less.

[0058] The average particle size D50 of amorphous alloy soft magnetic powder is not particularly limited, but is preferably 3.0 μm to 60.0 μm, and more preferably 5.0 μm to 50.0 μm. Because such amorphous alloy soft magnetic powder has a relatively small average particle size, it contributes to the realization of magnetic elements with low eddy current losses.

[0059] Furthermore, when the average particle size D50 is set to 20.0 μm or more and 40.0 μm or less, an amorphous alloy soft magnetic powder suitable for use in combination with other soft magnetic powders having a smaller average particle size is obtained. In other words, when amorphous alloy soft magnetic powder with an average particle size D50 in this range is compacted with other soft magnetic powders of smaller diameter, it contributes to further increasing the density of the compacted magnetic core compared to when each powder is compacted individually. Moreover, because amorphous alloy soft magnetic powder with an average particle size D50 in the aforementioned range has a high degree of amorphization even at large diameters, it contributes to the realization of magnetic elements with high permeability and low coercivity.

[0060] On the other hand, setting the average particle size D50 to 5.0 μm or more and 10.0 μm or less contributes to the realization of magnetic elements with particularly low eddy current losses.

[0061] The average particle size D50 of amorphous alloy soft magnetic powder is determined by the volume-based particle size distribution obtained by laser diffraction, and is the particle size at which the cumulative percentage from the smallest diameter side reaches 50%.

[0062] Furthermore, if the average particle size of the amorphous alloy soft magnetic powder falls below the lower limit, the particle size may become too small, potentially preventing sufficient filling during compaction. On the other hand, if the average particle size of the amorphous alloy soft magnetic powder exceeds the upper limit, the particle size may become too large, potentially preventing sufficient amorphization.

[0063] Furthermore, for amorphous alloy soft magnetic powder, when the particle size distribution obtained by laser diffraction is based on volume, and D10 is defined as the particle size when the cumulative total from the smallest diameter side reaches 10%, and D90 is defined as the particle size when the cumulative total from the smallest diameter side reaches 90%, then (D90-D10) / D50 is preferably between 1.3 and 3.0, and more preferably between 1.8 and 2.5. (D90-D10) / D50 is an index indicating the degree of spread of the particle size distribution, and when this index is within the above range, the packing performance of the amorphous alloy soft magnetic powder becomes particularly good. As a result, amorphous alloy soft magnetic powder is obtained that can be used to manufacture magnetic elements with particularly high magnetic permeability.

[0064] The coercivity of the amorphous alloy soft magnetic powder according to the embodiment is preferably 24 [A / m] or more (0.3 [Oe] or more) and 279 [A / m] or less (3.5 [Oe] or less), more preferably 40 [A / m] or more (0.5 [Oe] or more) and 239 [A / m] or less (3.0 [Oe] or less), and even more preferably 56 [A / m] or more (0.7 [Oe] or more) and 199 [A / m] or less (2.5 [Oe] or less).

[0065] By using amorphous alloy soft magnetic powder with low coercivity in this way, it is possible to manufacture magnetic elements that can sufficiently suppress hysteresis loss.

[0066] Furthermore, if the coercivity falls below the aforementioned lower limit, it becomes difficult to stably manufacture amorphous alloy soft magnetic powder with such low coercivity, and pursuing coercivity too much may affect the permeability. On the other hand, if the coercivity exceeds the aforementioned upper limit, it increases hysteresis loss, which may lead to increased iron loss in the compacted magnetic core.

[0067] The coercivity of amorphous alloy soft magnetic powder can be measured using a vibrating sample type magnetometer, such as the TM-VSM1230-MHHL manufactured by Tamagawa Seisakusho Co., Ltd.

[0068] The saturation magnetic flux density of the amorphous alloy soft magnetic powder according to the embodiment is preferably 1.60[T] or more and 2.20[T] or less, more preferably 1.60[T] or more and 2.10[T] or less, and even more preferably 1.65[T] or more and 2.00[T] or less.

[0069] By using amorphous alloy soft magnetic powder with a relatively high saturation magnetic flux density, it is possible to miniaturize and increase the power output of magnetic elements.

[0070] Furthermore, if the saturation magnetic flux density falls below the lower limit, it may become difficult to miniaturize and increase the output of the magnetic element. On the other hand, if the saturation magnetic flux density exceeds the upper limit, it becomes difficult to stably manufacture amorphous alloy soft magnetic powder with such a saturation magnetic flux density, and if the saturation magnetic flux density is pursued too much, it may affect the coercivity and lead to an increase in coercivity.

[0071] The saturation magnetic flux density of amorphous alloy soft magnetic powder is measured by the following method. First, the true specific gravity ρ of the soft magnetic powder is measured using a fully automated gas-displacement densimeter, Micromeristics AccuPyc1330. Next, the maximum magnetization Mm of the soft magnetic powder is measured using a vibrating sample magnetometer, Tamagawa Seisakusho Co., Ltd. VSM system, TM-VSM1230-MHHL. Then, the saturation magnetic flux density Bs is calculated using the following formula. Bs = 4π / 10000 × ρ × Mm

[0072] The permeability of the amorphous alloy soft magnetic powder according to this embodiment is preferably 18.0 or higher, and more preferably 20.0 or higher, at a measurement frequency of 100 kHz. Such amorphous alloy soft magnetic powder does not easily saturate in magnetic flux density even when a high magnetic field is applied, thus contributing to the realization of compacted magnetic cores with high saturation magnetic flux density and small compacted magnetic cores. The upper limit of the permeability is not particularly limited, but considering stable manufacturing, it is set to 50.0 or lower.

[0073] The permeability of amorphous alloy soft magnetic powder can be measured, for example, by fabricating a toroidal-shaped powder core and determining the relative permeability, i.e., effective permeability, from the self-inductance of the closed-circuit magnetic core coil. For measuring the permeability, an impedance analyzer such as the Agilent Technologies 4194A is used, with a measurement frequency of 1 MHz. The excitation coil has 7 turns, and the wire diameter of the windings is 0.6 mm.

[0074] In the amorphous alloy soft magnetic powder according to the embodiment, it is preferable that the apparent density and tap density are within a predetermined range. Specifically, the apparent density of the amorphous alloy soft magnetic powder [g / cm³] 3 When ] is set to 100, tap density [g / cm³ 3 The tap density is preferably between 103 and 120, more preferably between 105 and 115, and even more preferably between 107 and 113. Such amorphous alloy soft magnetic powder is relatively difficult to pack when not tapped (vibrated), but is easily packed when tapped. From this, it can be said that when the tap density is within the above range, the powder has a particle size distribution with relatively few irregularly shaped particles and high packing ability. Such amorphous alloy soft magnetic powder can be used to manufacture high-density compacted magnetic cores, and therefore the saturation magnetic flux density and permeability of magnetic elements can be particularly increased.

[0075] The apparent density of amorphous alloy soft magnetic powder is 4.55 [g / cm³]. 3 ] or more than 4.80[g / cm 3Preferably, it is 4.58 [g / cm³] or less. 3 ] or more than 4.70[g / cm 3 It is more preferable that it be less than or equal to the following:

[0076] The tap density of amorphous alloy soft magnetic powder is 4.95 [g / cm³]. 3 ] or more than 5.30[g / cm 3 Preferably, it is 5.00 [g / cm³] or less. 3 ] or more than 5.20[g / cm 3 It is more preferable that it be less than or equal to the following:

[0077] By having the apparent density and tap density of the amorphous alloy soft magnetic powder within the aforementioned range, the saturation magnetic flux density and permeability of the magnetic element can be particularly increased.

[0078] Furthermore, if the relative value of the tap density falls below the lower limit, the packing efficiency of the amorphous alloy soft magnetic powder may decrease when obtaining a compacted magnetic core by compacting the amorphous alloy soft magnetic powder. On the other hand, if the relative value of the tap density exceeds the upper limit, the shrinkage rate may increase when obtaining a compacted magnetic core by compacting the amorphous alloy soft magnetic powder. As a result, the compacted magnetic core may become more prone to deformation, and the dimensional accuracy may decrease.

[0079] The apparent density of amorphous alloy soft magnetic powder is measured in accordance with the metal powder apparent density measurement method specified in JIS Z 2504:2012.

[0080] The tap density of amorphous alloy soft magnetic powder is measured in accordance with the metal powder-tap density measurement method specified in JIS Z 2512:2012.

[0081] 1.5. Effects of the Embodiment As described above, the amorphous alloy soft magnetic powder according to the embodiment has a compositional formula Fe expressed in atomic ratio. a (Si 1-x B x ) b C c[However, the particles are composed of particles having a composition of 76.0 ≦ a ≦ 81.0, 16.0 ≦ b ≦ 22.0, 0 < c ≦ 3.0, and 0.5 ≦ x ≦ 0.9.]

[0082] When XAFS measurement is performed on such particles with the analysis depth set to the surface, the obtained Si-K absorption edge XANES spectrum has peak A and peak B. Peak A is a peak existing within the energy range of 1845 ± 1 eV. Peak B is a peak existing within the energy range of 1848 ± 1 eV. And when the intensity of peak A is A and the intensity of peak B is B, the intensity ratio A / B is 0.25 or less.

[0083] Particles having such a configuration have a high degree of amorphization. Therefore, the amorphous alloy soft magnetic powder according to the embodiment can achieve both high magnetic permeability and low coercive force.

[0084] In addition, in the amorphous alloy soft magnetic powder according to the present embodiment, after performing XAFS measurement on the particles with the analysis depth set to the bulk to obtain the Fe-K absorption edge EXAFS spectrum, the radial distribution function obtained by Fourier-transforming this Fe-K absorption edge EXAFS spectrum has peak C and peak D. Peak C is a peak existing within the range where the interatomic distance is 0.10 nm or more and 0.14 nm or less. Peak D is a peak existing within the range where the interatomic distance is 0.19 nm or more and 0.23 nm or less. And when the intensity of peak C is C and the intensity of peak D is D, it is preferable that the intensity ratio C / D is 0.5 or less.

[0085] Particles having such a configuration have a high degree of amorphization even when the Fe content is high, and can achieve both high magnetic permeability and low coercive force.

[0086] In addition, the radial distribution function having the above characteristics is a curve obtained by setting the analysis depth to the bulk. Therefore, the fact that this curve satisfies the above characteristics supports that the particles have a high degree of amorphization throughout.

[0087] Furthermore, of the radial distribution function described above, the maximum value in the range where the interatomic distance is less than 0.25 nm is defined as E, and the maximum value in the range where the interatomic distance is 0.25 nm or more is defined as F. In this case, it is preferable that the intensity ratio F / E is 0.5 or less.

[0088] This makes it possible to obtain amorphous alloy soft magnetic powder with a high degree of amorphousness, even with a high Fe content.

[0089] Furthermore, the amorphous alloy soft magnetic powder according to this embodiment preferably has an average particle size D50 of 3.0 μm or more and 60.0 μm or less. Also, the tap density [g / cm³] of the amorphous alloy soft magnetic powder according to this embodiment is 3 When the apparent density is set to 100, it is preferable that the value is between 103 and 120.

[0090] Such amorphous alloy soft magnetic powder has a relatively small average particle size and relatively few irregularly shaped particles. Therefore, the amorphous alloy soft magnetic powder according to this embodiment has high packing properties and can be used to manufacture high-density compacted magnetic cores.

[0091] Furthermore, the amorphous alloy soft magnetic powder according to this embodiment preferably has a magnetic permeability of 18.0 or higher at a measurement frequency of 100 kHz, and a coercivity of 24 [A / m] or higher (0.3 [Oe] or higher) and 279 [A / m] or lower (3.5 [Oe] or lower).

[0092] Such amorphous alloy soft magnetic powders can achieve a particularly high degree of compatibility between high permeability and low coercivity.

[0093] 2. Method for producing amorphous alloy soft magnetic powder Next, a method for producing amorphous alloy soft magnetic powder according to the embodiment will be described.

[0094] The amorphous alloy soft magnetic powder according to this embodiment may be manufactured by any manufacturing method, for example, by atomization methods such as water atomization, gas atomization, and rotary water flow atomization, reduction methods, carbonyl methods, and pulverization methods.

[0095] Atomization methods include water atomization, gas atomization, and rotary water flow atomization, depending on the type of coolant and the configuration of the apparatus. Of these, amorphous alloy soft magnetic powder is preferably manufactured by atomization, more preferably by water atomization or rotary water flow atomization, and even more preferably by rotary water flow atomization. The atomization method is a method of producing powder by pulverizing and cooling molten raw materials by colliding them with a fluid such as liquid or gas that is sprayed at high speed.

[0096] In this specification, "water atomization method" refers to a method of producing metal powder by using a liquid such as water or oil as a coolant, spraying it in an inverted cone shape focused to a single point, and then flowing molten metal down towards this point of focus and causing it to collide with the coolant.

[0097] On the other hand, the rotary water atomization method allows for extremely rapid cooling of the molten metal, making it particularly easy to achieve amorphous state.

[0098] When producing amorphous alloy soft magnetic powder, the cooling rate of the molten metal is 10 6 It is preferable that it is greater than [K / sec], and 10 7 A temperature of [K / sec] or higher is more preferable. This allows for the acquisition of amorphous alloy soft magnetic powder with sufficient amorphization. In other words, even with a composition that has a relatively high Fe content, amorphization can be achieved, and amorphous alloy soft magnetic powder can be obtained from which spectra with the aforementioned characteristics can be acquired by XAFS measurement. In particular, according to the rotating water flow atomization method, 10 6 Cooling speeds exceeding [K / sec] can be easily achieved.

[0099] The following describes the method for producing amorphous alloy soft magnetic powder using the rotary water atomization method.

[0100] In the rotary water atomization method, a coolant is injected and supplied along the inner surface of a cooling cylinder, and by swirling it along the inner surface of the cooling cylinder, a coolant layer is formed on the inner surface. On the other hand, the raw material for amorphous alloy soft magnetic powder is melted, and while the resulting molten metal is allowed to fall naturally, a jet of liquid or gas is blown onto it. When the molten metal is scattered in this way, the scattered molten metal is incorporated into the coolant layer. As a result, the scattered and finely powdered molten metal is rapidly cooled and solidified, yielding amorphous alloy soft magnetic powder.

[0101] Figure 1 is a longitudinal cross-sectional view showing an example of an apparatus for producing amorphous alloy soft magnetic powder by the rotary water atomization method.

[0102] The powder manufacturing apparatus 30 shown in Figure 1 comprises a cooling cylinder 1, a crucible 15, a pump 7, and a jet nozzle 24. The cooling cylinder 1 is a cylinder for forming a cooling liquid layer 9 on its inner circumferential surface. The crucible 15 is a supply container for supplying molten metal 25 flowing down into the space 23 inside the cooling liquid layer 9. The pump 7 supplies cooling liquid to the cooling cylinder 1. The jet nozzle 24 ejects a gas jet 26 that divides the flowing molten metal 25 into droplets. The molten metal 25 is prepared according to the composition of the amorphous alloy soft magnetic powder.

[0103] The cooling cylinder 1 is cylindrical in shape and is installed so that its axis is aligned with the vertical direction, or tilted at an angle of 30° or less with respect to the vertical direction.

[0104] The upper end opening of the cooling cylinder 1 is closed by a lid 2. The lid 2 has an opening 3 formed therein for supplying the flowing molten metal 25 to the space 23 of the cooling cylinder 1.

[0105] The upper part of the cooling cylinder 1 is provided with a coolant ejection pipe 4 that ejects coolant onto the inner circumferential surface of the cooling cylinder 1. Multiple outlets 5 of the coolant ejection pipe 4 are provided at equal intervals along the circumferential direction of the cooling cylinder 1.

[0106] The coolant discharge pipe 4 is connected to the tank 8 via piping to which the pump 7 is connected. The coolant in the tank 8, drawn up by the pump 7, is discharged into the cooling cylinder 1 via the coolant discharge pipe 4. As a result, the coolant gradually flows down along the inner surface of the cooling cylinder 1 while rotating, forming a coolant layer 9 along the inner surface. Coolers may be interposed in the tank 8 or along the circulation path as needed. In addition to water, oils such as silicone oil can be used as the coolant, and various additives may also be added. Furthermore, by removing dissolved oxygen from the coolant beforehand, oxidation of the manufactured powder can be suppressed.

[0107] Furthermore, a cylindrical draining mesh 17 is attached to the lower part of the cooling cylinder 1, and a funnel-shaped powder collection container 18 is provided on the underside of this draining mesh 17. A coolant collection cover 13 is provided around the draining mesh 17 so as to cover it, and a drain port 14 formed at the bottom of this coolant collection cover 13 is connected to the tank 8 via piping.

[0108] The jet nozzle 24 is located in the space 23. The jet nozzle 24 is attached to the end of a gas supply pipe 27 inserted through the opening 3 of the cover 2, and its nozzle is positioned to direct the flowing molten metal 25.

[0109] In order to produce amorphous alloy soft magnetic powder using such a powder manufacturing apparatus 30, first, the pump 7 is operated to form a coolant layer 9 on the inner surface of the cooling cylinder 1. Next, the molten metal 25 in the crucible 15 is allowed to flow down into the space 23. When the gas jet 26 is blown onto the flowing molten metal 25, the molten metal 25 is scattered, and the pulverized molten metal 25 is drawn into the coolant layer 9. As a result, the pulverized molten metal 25 cools and solidifies, yielding amorphous alloy soft magnetic powder.

[0110] In the rotary water atomization method, a very high cooling rate can be stably maintained by continuously supplying the cooling liquid, thereby promoting the amorphization of the amorphous alloy soft magnetic powder produced.

[0111] Furthermore, the molten metal 25, which has been refined to a certain size by the gas jet 26, falls by inertia until it is drawn into the coolant layer 9, and during this process, the droplets become spherical. As a result, amorphous alloy soft magnetic powder with a good particle size distribution and excellent packing properties can be produced.

[0112] For example, the amount of molten metal 25 flowing down from the crucible 15 varies depending on the size of the apparatus, but it is preferably more than 1.0 kg / min and 20.0 kg / min or less, and more preferably 2.0 kg / min or more and 10.0 kg / min or less. This allows for the optimization of the amount of molten metal 25 flowing down in a given time, thereby ensuring sufficient amorphization and enabling the efficient production of amorphous alloy soft magnetic powder from which spectra with the aforementioned characteristics can be obtained by XAFS measurement. Furthermore, the cooling rate of molten metal 25 per unit amount can be increased, thereby increasing the degree of amorphization.

[0113] Furthermore, the pressure of the gas jet 26 varies slightly depending on the configuration of the jet nozzle 24, but is preferably between 2.0 MPa and 20.0 MPa, and more preferably between 3.0 MPa and 10.0 MPa. This optimizes the particle size when the molten metal 25 is scattered, ensuring sufficient amorphization and enabling the production of amorphous alloy soft magnetic powder from which a spectrum with the aforementioned characteristics can be obtained by XAFS measurement. In other words, if the pressure of the gas jet 26 falls below the lower limit, it becomes difficult to scatter the molten metal finely enough, and the particle size tends to become larger. This can lead to a decrease in the cooling rate inside the droplets, potentially resulting in insufficient amorphization. On the other hand, if the pressure of the gas jet 26 exceeds the upper limit, the particle size of the scattered droplets may become too small. This can lead to the droplets being slowly cooled by the gas jet 26, preventing rapid cooling by the cooling liquid layer 9, potentially resulting in insufficient amorphization.

[0114] Furthermore, the flow rate of the gas jet 26 is not particularly limited, but is 1.0 [Nm³]. 3 / min] or more than 20.0[Nm 3 It is preferable that it be less than or equal to [ / minute].

[0115] The pressure at which the coolant is ejected from the cooling cylinder 1 is preferably between 5 MPa and 200 MPa, and more preferably between 10 MPa and 100 MPa. This optimizes the flow velocity of the coolant layer 9, making it less likely for the pulverized molten metal 25 to become irregularly shaped. As a result, amorphous alloy soft magnetic powder with superior packing properties can be obtained. Furthermore, the cooling rate of the molten metal 25 by the coolant can be sufficiently increased. Amorphous alloy soft magnetic powder is obtained in the manner described above.

[0116] Furthermore, the particle size of the amorphous alloy soft magnetic powder can be reduced by, for example, reducing the amount of molten metal 25 flowing from the crucible 15, increasing the pressure of the gas jet 26, or increasing the flow rate of the gas jet 26. Conversely, the particle size can be increased by performing the opposite operations.

[0117] Furthermore, the particle size distribution of the amorphous alloy soft magnetic powder can be narrowed, for example, by setting the flow rate of the molten metal 25, the pressure and flow rate of the gas jet 26 within the aforementioned range. This setting can increase the ratio of tap density to apparent density of the amorphous alloy soft magnetic powder.

[0118] Furthermore, amorphous alloy soft magnetic powder may be subjected to classification treatment as needed. Examples of classification treatment methods include dry classification such as sieving classification, inertial classification, centrifugal classification, and wind classification, and wet classification such as sedimentation classification.

[0119] Furthermore, if necessary, an insulating film may be formed on the surface of each particle of the obtained soft magnetic powder. The constituent material of this insulating film is not particularly limited, but examples include inorganic materials such as phosphates such as magnesium phosphate, calcium phosphate, zinc phosphate, manganese phosphate, and cadmium phosphate, and silicates such as sodium silicate.

[0120] 3. Compacted magnetic cores and magnetic elements Next, the powdered magnetic core and magnetic element according to the embodiment will be described.

[0121] The magnetic element according to this embodiment is applicable to various magnetic elements equipped with a magnetic core, such as choke coils, inductors, noise filters, reactors, transformers, motors, actuators, solenoid valves, and generators. Furthermore, the compacted magnetic core according to this embodiment is applicable to the magnetic cores provided in these magnetic elements.

[0122] Below, we will describe two types of coil components as representative examples of magnetic elements. 3.1. Toroidal type First, a toroidal coil component, which is a magnetic element according to the embodiment, will be described.

[0123] Figure 2 is a schematic plan view of a toroidal coil component. The coil component 10 shown in Figure 2 has a ring-shaped powder core 11 and a conductor 12 wound around this powder core 11.

[0124] The compacted magnetic core 11 is obtained by mixing the amorphous alloy soft magnetic powder and a binder as described above, supplying the resulting mixture to a mold, and then pressurizing and molding it. In other words, the compacted magnetic core 11 is a compacted body containing the amorphous alloy soft magnetic powder according to the embodiment. Such a compacted magnetic core 11 has high magnetic permeability and low coercivity. Therefore, when a coil component 10 having the compacted magnetic core 11 is mounted in an electronic device, the power consumption of the electronic device can be reduced, and the electronic device can be made smaller and have higher output.

[0125] Furthermore, the coil component 10 is equipped with such a powdered magnetic core 11. Such a coil component 10 contributes to the miniaturization and increased power output of electronic devices.

[0126] Examples of constituent materials for the binder used in the production of the compacted magnetic core 11 include organic materials such as silicone resins, epoxy resins, phenolic resins, polyamide resins, polyimide resins, and polyphenylene sulfide resins, and inorganic materials such as phosphates like magnesium phosphate, calcium phosphate, zinc phosphate, manganese phosphate, and cadmium phosphate, and silicates like sodium silicate.

[0127] The materials used to construct the conductor 12 include highly conductive materials, such as metallic materials containing Cu, Al, Ag, Au, Ni, etc. An insulating film may be provided on the surface of the conductor 12 as needed.

[0128] The shape of the compacted magnetic core 11 is not limited to the ring shape shown in Figure 2; for example, it may be a shape in which a part of the ring is missing, or a shape in which the longitudinal direction is straight.

[0129] Furthermore, the compacted magnetic core 11 may, if necessary, contain soft magnetic powders or non-magnetic powders other than the amorphous alloy soft magnetic powder according to the embodiment described above. In that case, the proportion of the amorphous alloy soft magnetic powder in the mixed powder obtained by mixing each powder is preferably more than 50% by mass, and more preferably 60% by mass or more.

[0130] 3.2. Closed Magnetic Circuit Type Next, we will describe a closed-circuit type coil component, which is a magnetic element according to the embodiment. Figure 3 is a schematic transmission perspective view showing a closed magnetic circuit type coil component.

[0131] The following describes closed-circuit type coil components, focusing on the differences from toroidal type coil components, and omitting explanations of similar aspects.

[0132] The coil component 20 shown in Figure 3 comprises a chip-shaped powder core 21 and a conductor 22 embedded inside the powder core 21 and formed into a coil. That is, the powder core 21 is a powder compact containing amorphous alloy soft magnetic powder according to the embodiment. Such a powder core 21 has high magnetic permeability and low coercivity.

[0133] Furthermore, the coil component 20 is equipped with such a compacted magnetic core 21. Such a coil component 20 contributes to the miniaturization and increased power output of electronic devices.

[0134] The compacted magnetic core 21 may, if necessary, contain soft magnetic powders or non-magnetic powders other than the amorphous alloy soft magnetic powder according to the embodiment described above. In that case, the proportion of the amorphous alloy soft magnetic powder in the mixed powder is preferably more than 50% by mass, and more preferably 60% by mass or more.

[0135] 4.Electronic equipment Next, an electronic device equipped with a magnetic element according to the embodiment will be described with reference to Figures 4 to 6.

[0136] Figure 4 is a perspective view showing a mobile personal computer, which is an electronic device equipped with magnetic elements according to an embodiment. The personal computer 1100 shown in Figure 4 comprises a main body 1104 equipped with a keyboard 1102 and a display unit 1106 equipped with a display unit 100. The display unit 1106 is rotatably supported by the main body 1104 via a hinge structure. Such a personal computer 1100 incorporates magnetic elements 1000, such as a choke coil or inductor for a switching power supply, or a motor.

[0137] Figure 5 is a plan view showing a smartphone, which is an electronic device equipped with magnetic elements according to an embodiment. The smartphone 1200 shown in Figure 5 is equipped with a plurality of operation buttons 1202, an earpiece 1204, and a microphone 1206. A display unit 100 is also positioned between the operation buttons 1202 and the earpiece 1204. Such a smartphone 1200 incorporates magnetic elements 1000, such as inductors, noise filters, and motors.

[0138] Figure 6 is a perspective view showing a digital still camera, which is an electronic device equipped with a magnetic element according to the embodiment. The digital still camera 1300 generates an imaging signal by photoelectric conversion of the light image of the subject using an image sensor such as a CCD (Charge Coupled Device).

[0139] The digital still camera 1300 shown in Figure 6 includes a display unit 100 located on the back of the case 1302. The display unit 100 functions as a viewfinder, displaying the subject as an electronic image. A light-receiving unit 1304, including an optical lens and a CCD, is provided on the front side of the case 1302, i.e., the back side in the figure.

[0140] When the photographer confirms the subject image displayed on the display unit 100 and presses the shutter button 1306, the imaging signal from the CCD at that moment is transferred and stored in the memory 1308. Such a digital still camera 1300 also incorporates magnetic elements 1000, such as an inductor and a noise filter.

[0141] In addition to the personal computer in Figure 4, the smartphone in Figure 5, and the digital still camera in Figure 6, other examples of electronic devices according to this embodiment include mobile phones, tablet terminals, watches, inkjet printers and other inkjet ejection devices, laptop personal computers, televisions, video cameras, video tape recorders, car navigation systems, pagers, electronic organizers, electronic dictionaries, calculators, electronic game consoles, word processors, workstations, video phones, security television monitors, electronic binoculars, POS terminals, electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasound diagnostic devices, medical devices such as electronic endoscopes, fish finders, various measuring instruments, instruments for vehicles, aircraft, and ships, mobile control devices such as automobile control equipment, aircraft control equipment, railway vehicle control equipment, and ship control equipment, and flight simulators.

[0142] As described above, such electronic devices are equipped with magnetic elements according to the embodiment. This allows the effects of the magnetic element, such as high permeability and low coercivity, to be enjoyed, enabling miniaturization and increased output of the electronic devices.

[0143] The amorphous alloy soft magnetic powder, compacted magnetic core, magnetic element, and electronic device of the present invention have been described above based on preferred embodiments, but the present invention is not limited thereto. For example, the compacted magnetic core and magnetic element according to the present invention may be in which each part of the above embodiment is replaced with any component having a similar function, or any component may be added to the above embodiment.

[0144] Furthermore, although the embodiments described above used a compacted magnetic core as an example of an application for the amorphous alloy soft magnetic powder of the present invention, the application examples are not limited to this, and may include magnetic fluids, magnetic shielding sheets, magnetic heads, and other magnetic devices. Also, the shape of the compacted magnetic core and magnetic element is not limited to those shown in the figures, and may be any shape. [Examples]

[0145] Next, specific embodiments of the present invention will be described. 5. Manufacturing of powdered magnetic cores 5.1. Sample No. 1 First, the raw materials were melted in a high-frequency induction furnace and then pulverized by a rotary water atomization method to obtain amorphous alloy soft magnetic powder. During this process, the flow rate of the molten metal from the crucible was set to 10.0 kg / min, the gas jet pressure to 10.0 MPa, and the gas jet flow rate to 10.0 Nm³. 3 The cooling rate was set to 10 [ / min], and the coolant pressure was set to 40 MPa. The cooling rate was set to 10 [ / min]. 7 It was [K / sec].

[0146] Next, classification was performed using a classifier with a mesh opening of 150 μm. The alloy composition of the amorphous alloy soft magnetic powder after classification is shown in Table 1. A solid-state emission spectrometer, model: SPECTROLAB, type: LAVMB08A, manufactured by SPECTRO, was used to determine the alloy composition.

[0147] Next, the obtained amorphous alloy soft magnetic powder was mixed with an epoxy resin as a binder and toluene as an organic solvent to obtain a mixture. The amount of epoxy resin added was 2 parts by mass per 100 parts by mass of amorphous alloy soft magnetic powder.

[0148] Next, the resulting mixture was stirred and then dried for a short time to obtain a lumpy dried body. This dried body was then sieved through a 400 μm mesh to pulverize it and obtain granulated powder. The obtained granulated powder was dried at 50°C for 1 hour.

[0149] Next, the obtained granulated powder was filled into a mold, and a molded body was obtained based on the following molding conditions.

[0150] <Molding conditions> • Forming method: Press forming • Shape of the molded body: ring-shaped • Dimensions of the molded body: Outer diameter 14mm, inner diameter 8mm, thickness 3mm ·Molding pressure: 3t / cm 2 (294 MPa)

[0151] Next, the molded body was heated in an air atmosphere at a temperature of 150°C for 0.50 hours to cure the binder. This yielded a compacted magnetic core.

[0152] 5.2. Samples No. 2-5 A compacted magnetic core was obtained in the same manner as for Sample No. 1, except that the amorphous alloy soft magnetic powders shown in Table 1 were used. At this time, the flow rate of the molten metal was adjusted within the range of 2.0 kg / min to 10.0 kg / min, and the gas jet pressure was adjusted within the range of 3.0 MPa to 10.0 MPa to produce powders that yielded the XAFS measurement results shown in Table 1.

[0153] 5.3. Samples No. 6-8 Except for using the water atomization method instead of the rotary water atomization method, amorphous alloy soft magnetic powder with the composition shown in Table 1 was manufactured in the same manner as for Sample No. 1, and a compacted magnetic core was obtained. The cooling rate using the water atomization method was 10 6 The temperature was [K / sec]. Furthermore, by adjusting the flow rate of the molten metal within the range of 2.0 [kg / min] to 10.0 [kg / min], powder was produced that yielded the XAFS measurement results shown in Table 1.

[0154] 5.4. Samples No. 9-11 Except for using the amorphous alloy soft magnetic powders shown in Table 1, compacted magnetic cores were obtained in the same manner as Sample No. 6. In Samples No. 9 to 11, the cooling rate was changed by modifying the conditions in the water atomization method. 6 The temperature was less than [K / sec]. Furthermore, by increasing the flow rate of molten metal compared to samples No. 6-8, powder was produced that yielded the XAFS measurement results shown in Table 1.

[0155] In Table 1, amorphous alloy soft magnetic powders corresponding to the present invention are labeled as "Examples," while those not corresponding to the present invention are labeled as "Comparative Examples."

[0156] 6. Evaluation of amorphous alloy soft magnetic powder and magnetic elements 6.1. XAFS Measurement of Amorphous Alloy Soft Magnetic Powder XAFS measurements were performed on the amorphous alloy soft magnetic powders of Sample No. 1 (Example) and Sample No. 9 (Comparative Example), which are representative of the amorphous alloy soft magnetic powders obtained in each example and comparative example. The measurement results are shown in Figures 7 and 8.

[0157] 6.1.1. Si-K absorption edge XANES spectrum obtained with analysis depth set to the surface Figure 7 shows the Si-K absorption edge XANES spectra obtained for amorphous alloy soft magnetic powders of Sample No. 1 (Example) and Sample No. 9 (Comparative Example), with the analysis depth set to the surface.

[0158] As shown in Figure 7, peak A has a shoulder structure, and peak B has an upward-convex shape. The intensity ratio A / B was calculated from these peaks. The calculation results are shown in Table 1.

[0159] Furthermore, the intensity ratio A / B was similarly calculated for the amorphous alloy soft magnetic powders of other examples and comparative examples. The calculation results are shown in Table 1. In the XANES spectra shown in Figure 7, the position of the Si-K absorption edge is estimated to be 1839 eV.

[0160] 6.1.2. Radial distribution function based on Fe-K absorption edge EXAFS spectrum obtained with analysis depth set to bulk. Figure 8 shows the radial distribution function based on the Fe-K absorption edge EXAFS spectra obtained by setting the analysis depth to bulk for amorphous alloy soft magnetic powders of Sample No. 1 (Example) and Sample No. 9 (Comparative Example).

[0161] As shown in Figure 8, the obtained radial distribution function showed peaks C and D. The heights of these peaks were obtained, and the intensity ratio C / D was calculated. The calculation results are shown in Table 1.

[0162] Furthermore, the intensity ratio C / D was similarly calculated for the amorphous alloy soft magnetic powders of other examples and comparative examples. The calculation results are shown in Table 1.

[0163] Furthermore, in the radial distribution function shown in Figure 8, the intensity ratio F / E was calculated when E was defined as the maximum value in the range where the interatomic distance is less than 0.25 nm, and F was defined as the maximum value in the range where the interatomic distance is 0.25 nm or greater. The calculation results are shown in Table 1.

[0164] Furthermore, the intensity ratio F / E was similarly calculated for the amorphous alloy soft magnetic powders of other examples and comparative examples. The calculation results are shown in Table 1.

[0165] [Table 1]

[0166] As is clear from Table 1, in each example of amorphous alloy soft magnetic powder, the intensity ratio of the peaks in the XANES spectrum and the intensity ratio of the peaks in the radial distribution function were both within the predetermined range. In contrast, in each comparative example of amorphous alloy soft magnetic powder, these intensity ratios were all outside the predetermined range.

[0167] 6.2. Crystallinity of amorphous alloy soft magnetic powder Furthermore, the degree of crystallinity of the obtained amorphous alloy soft magnetic powder was measured using an X-ray diffractometer. The measurement results are shown in Table 2.

[0168] Furthermore, Figure 9 shows the X-ray diffraction profiles obtained using an X-ray diffractometer for amorphous alloy soft magnetic powder of Sample No. 1 (Example) and Sample No. 9 (Comparative Example). As shown in Figure 9, no peaks were observed in the X-ray diffraction profile obtained from the amorphous alloy soft magnetic powder of Sample No. 1, indicating that sufficient amorphousization had been achieved. In contrast, a peak was observed in the X-ray diffraction profile obtained from the amorphous alloy soft magnetic powder of Sample No. 9, indicating that crystallization had occurred.

[0169] 6.3. Powder properties of amorphous alloy soft magnetic powders Next, particle size distribution measurements were performed on the amorphous alloy soft magnetic powders obtained in each example and comparative example. This measurement was carried out using a laser diffraction particle size distribution analyzer, the Microtrac HRA9320-X100, manufactured by Nikkiso Co., Ltd. D10, D50, D90, and (D90-D10) / D50 were then calculated. The calculation results are shown in Table 2.

[0170] Furthermore, the apparent density AD and tap density TD were measured for the amorphous alloy soft magnetic powders obtained in each example and comparative example. The relative value of the tap density TD, i.e., the ratio of tap density to apparent density, was calculated when the apparent density AD was set to 100. The calculation results are shown in Table 2.

[0171] 6.4 Coercivity of Amorphous Alloy Soft Magnetic Powder The coercivity of the amorphous alloy soft magnetic powders obtained in each example and comparative example was measured. The measurement results are shown in Table 2.

[0172] 6.5 Permeability of Magnetic Elements Using the compacted magnetic cores obtained in each example and comparative example, magnetic elements were fabricated under the following manufacturing conditions.

[0173] • Constructive material of the conductor: Cu • Wire diameter: 0.6mm • Number of turns (when measuring magnetic permeability): 7 turns • Number of turns (when measuring core loss): 36 turns on the primary side, 36 turns on the secondary side Next, the permeability of the fabricated magnetic element was measured at a frequency of 100 kHz using an impedance analyzer. The obtained permeability was then evaluated against the following evaluation criteria.

[0174] A: The magnetic permeability is 20 or higher. B: Permeability is 17 or higher and less than 20. C: Permeability is 14 or greater and less than 17. D: Permeability is less than 14 The evaluation results are shown in Table 2.

[0175] [Table 2]

[0176] As shown in Table 2, the amorphous alloy soft magnetic powders obtained in each example were found to have higher magnetic permeability and lower coercivity compared to the amorphous alloy soft magnetic powders obtained in each comparative example. Furthermore, the amorphous alloy soft magnetic powders obtained in each example were found to have a lower degree of crystallinity compared to the amorphous alloy soft magnetic powders obtained in each comparative example.

[0177] From the above, it was found that by satisfying the specified conditions in the XAFS measurement results, sufficient amorphousization can be achieved, resulting in an amorphous alloy soft magnetic powder that achieves both high permeability and low coercivity.

[0178] Furthermore, it was found that the permeability of the magnetic element can be increased by optimizing (D90-D10) / D50 and the ratio of tap density to apparent density.

[0179] Furthermore, the P content in the amorphous alloy soft magnetic powder of each example was within the range of 0.0050% by mass to 0.0150% by mass, and the S / P ratio was within the range of 0.2 to 0.8. In contrast, the S / P ratio of the amorphous alloy soft magnetic powder of each comparative example was outside the range of 0.2 to 0.8. Therefore, it is considered that these trace elements also influenced the difference in properties between the examples and the comparative examples. Table 1 shows the S / P ratio for each example and each comparative example. [Explanation of Symbols]

[0180] 1...Cooling cylinder, 2...Lid, 3...Opening, 4...Coolant ejection tube, 5...Discharge port, 7...Pump, 8...Tank, 9...Coolant layer, 10...Cooling components, 11...Powdered magnetic core, 12...Wire, 13...Cooling liquid recovery cover, 14...Drain port, 15...Crucible, 17...Drainage mesh, 18...Powder recovery container, 20...Coil components, 21...Powdered magnetic core, 22...Wire, 23...Space, 24...Jet nozzle, 25...Molten metal, 26...Gas jet, 27...Gas Supply pipe, 30... Powder manufacturing device, 100... Display unit, 1000... Magnetic element, 1100... Personal computer, 1102... Keyboard, 1104... Main unit, 1106... Display unit, 1200... Smartphone, 1202... Operation buttons, 1204... Earpiece, 1206... Transmitter, 1300... Digital still camera, 1302... Case, 1304... Light receiving unit, 1306... Shutter button, 1308... Memory

Claims

1. Composition formula Fe expressed in atomic ratio ａ (Si １－ｘ B ｘ ) ｂ C ｃ [However, a, b, c, and x are such that 76.0 ≤ a ≤ 81.0, 16.0 ≤ b ≤ 22.0, 0 < c ≤ 3.0, and 0.5 ≤ x ≤ 0.9.] It is composed of particles having the following composition: When XAFS measurement is performed on the aforementioned particles with the analysis depth set to the surface, the obtained Si-K absorption edge XANES spectrum is: Peak A, whose energy is within the range of 1845 ± 1 eV, Peak B, whose energy is within the range of 1848 ± 1 eV, It has, Let the intensity of the aforementioned peak A be A. When the intensity of the aforementioned peak B is denoted as B, Amorphous alloy soft magnetic powder characterized by having an intensity ratio A / B of 0.12 or more and 0.23 or less.

2. For the aforementioned particles, an XAFS measurement is performed with the analysis depth set to bulk, and after obtaining the Fe-K absorption edge EXAFS spectrum, the radial distribution function obtained by Fourier transforming the Fe-K absorption edge EXAFS spectrum is: Peak C, which is located in the range of 0.10 nm to 0.14 nm in terms of interatomic distance, Peak D, which is located in the range of 0.19 nm to 0.23 nm in terms of interatomic distance, It has, Let C be the intensity of the aforementioned peak C. When the intensity of the aforementioned peak D is denoted as D, The amorphous alloy soft magnetic powder according to claim 1, wherein the strength ratio C / D is 0.5 or less.

3. When E is the maximum value of the radial distribution function in the range where the interatomic distance is less than 0.25 nm, and F is the maximum value in the range where the interatomic distance is 0.25 nm or more, The amorphous alloy soft magnetic powder according to claim 2, wherein the strength ratio F / E is 0.5 or less.

4. The average particle size is 3.0 μm or more and 60.0 μm or less. Tap density [g / cm³] ３ The amorphous alloy soft magnetic powder according to claim 1 or 2, wherein the apparent density is 103 or more and 120 or less when the apparent density is set to 100.

5. The magnetic permeability at a measurement frequency of 100 kHz is 18.0 or higher. The amorphous alloy soft magnetic powder according to claim 1 or 2, wherein the coercivity is 24 [A / m] (0.3 [Oe]) or more and 279 [A / m] (3.5 [Oe]) or less.

6. A compacted magnetic core characterized by containing amorphous alloy soft magnetic powder as described in claim 1 or 2.

7. A magnetic element characterized by comprising a compacted magnetic core as described in claim 6.

8. An electronic device characterized by comprising the magnetic element described in claim 7.

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