Method for producing amorphous alloy soft magnetic powder

Abstract

To provide amorphous alloy soft magnetic powder combining high saturated magnetic flux density and low coercive force, a powder magnetic core and magnetic device containing the magnetic powder like this, as well as, an electronic device capable of realizing down sizing and high output.SOLUTION: Amorphous alloy soft magnetic powder having a composition represented by (FexCo1-x)100-(a+b)(SiyB1-y)aMb [M is at least one selected from the group consisting of C, S, P, Sn, Mo, Cu and Nb; x, y, a and b are 0.73≤x≤0.85, 0.02≤y≤0.10, 13.0≤a≤19.0, and 0≤b≤2.0.], wherein when XAFS measurement is performed on the particles, a resulting Si-K absorption edge XANES spectrum has a peak A present at 1842±1 eV, a peak B present at 1845±1 eV, and a peak C present at 1848±1 eV, and an intensity ratio A / C of 0.40 or less and an intensity ratio B / C of 0.60 or less.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to amorphous alloy soft magnetic powder. Manufacturing method

Background Art

[0002] In various electronic devices equipped with magnetic elements, in order to achieve miniaturization and high output, it is necessary to increase the saturation magnetic flux density while maintaining low coercive force for the soft magnetic powder contained in the compacted magnetic core.

[0003] Patent Document 1 discloses a soft magnetic alloy powder having a main component composed of a composition formula (Fe (1-(α+β) )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, and M is one or more selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W, Ti and V. In this powder, 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, 0≦α + β≦0.50. Also, Patent Document 1 discloses that by selecting Co as X1, the saturation magnetization after heat treatment can be improved.

Prior Art Documents

Patent Documents

[0004] [

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the soft magnetic alloy powder described in Patent Document 1 still has room for improvement in terms of increasing the saturation magnetization while achieving a low coercive magnetization. That is, in soft magnetic powder, it is an issue to achieve both a high saturation magnetic flux density and a low coercive force.

Means for Solving the Problems

[0006] The amorphous alloy soft magnetic powder according to the application example of the present invention Manufacturing method is The process of melting raw materials to obtain molten metal, A step to obtain amorphous alloy soft magnetic powder by pulverizing the molten metal using a rotating water atomization method while cooling and solidifying it, It has, The amorphous alloy soft magnetic powder is (Fe x Co 1-x ) 100-(a+b) (Si y B 1-y ) a M b [M is at least one selected from the group consisting of C, S, P, Sn, Mo, Cu, and Nb, x, y, a, and b are 0.73 ≤ x ≤ 0.85, 0.02 ≤ y ≤ 0.10, 13.0 ≤ a ≤ 19.0, 0 ≤ b ≤ 2.0.] has a composition represented by The average particle size D50 is between 10.0 μm and 60.0 μm. When XAFS measurement is performed by setting the analysis depth for particles to the bulk, the obtained Si-K absorption edge XANES spectrum has a peak A existing within the energy range of 1842 ± 1 eV, a peak B existing within the energy range of 1845 ± 1 eV, a peak C existing within the energy range of 1848 ± 1 eV, and taking the intensity of the peak A as A, Let the intensity of the aforementioned peak B be B. When the intensity of the aforementioned peak C is denoted as C, The intensity ratio A / C is 0.40 or less. It is characterized by having a strength ratio B / C of 0.60 or less. [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. 3 (Example) and Sample No. 30 (Comparative Example). [Figure 8] Figure 7 shows a graph comparing the intensity ratios A / C and B / C obtained from the Si-K absorption edge XANES spectra. [Figure 9] This shows the radial distribution function based on the Si-K absorption edge EXAFS spectra obtained for amorphous alloy soft magnetic powders of Sample No. 3 (Example) and Sample No. 30 (Comparative Example). [Figure 10] Figure 9 shows a graph comparing the intensity ratios E / D and F / D obtained from the radial distribution function. [Figure 11]This shows the radial distribution function based on the Fe-K absorption edge EXAFS spectra obtained for amorphous alloy soft magnetic powders of Sample No. 3 (Example) and Sample No. 30 (Comparative Example). [Figure 12] Figure 11 shows a graph comparing the intensity ratio H / G and intensity ratio I / G obtained from the radial distribution function. [Figure 13] This is the radial distribution function based on the Co-K absorption edge EXAFS spectra obtained for the surface of amorphous alloy soft magnetic powders of Sample No. 3 (Example) and Sample No. 30 (Comparative Example). [Figure 14] Figure 13 shows a graph comparing the intensity ratios K / J and L / J obtained from the radial distribution function. [Figure 15] This shows the radial distribution function based on the Co-K absorption edge EXAFS spectra obtained for bulk amorphous alloy soft magnetic powders of Sample No. 3 (Example) and Sample No. 30 (Comparative Example). [Figure 16] Figure 15 shows a graph comparing the intensity ratio N / M and intensity ratio O / M obtained from the radial distribution function. [Modes for carrying out the invention]

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

[0012] 1. Amorphous alloy soft magnetic powder The amorphous alloy soft magnetic powder according to this embodiment is an amorphous alloy powder exhibiting soft magnetism. While the amorphous alloy soft magnetic powder can be applied to any application, it can be formed, for example, by bonding the particles together. This yields a compacted magnetic core used in magnetic elements.

[0013] The amorphous alloy soft magnetic powder according to this embodiment is (Fe x Co 1-x ) 100-(a+b) (Si y B1-y ) a M b The powder has the composition represented by , where M is at least one selected from the group consisting of C, S, P, Sn, Mo, Cu, and Nb. Also, x, y, a, and b are 0.73 ≤ x ≤ 0.85, 0.02 ≤ y ≤ 0.10, 13.0 ≤ a ≤ 19.0, and 0 ≤ b ≤ 2.0.

[0014] Furthermore, when this amorphous alloy soft magnetic powder is subjected to XAFS measurement with the analysis depth set to bulk, the resulting Si-K absorption edge XANES spectrum satisfies the following characteristics: When the intensity of peak A, where the X-ray energy is in the range of 1842±1eV, is denoted as A, the intensity of peak B, where the energy is in the range of 1845±1eV, is denoted as B, and the intensity of peak C, where the energy is in the range of 1848±1eV, is denoted as C, the intensity ratio A / C is 0.40 or less, and the intensity ratio B / C is 0.60 or less.

[0015] Such amorphous alloy soft magnetic powders achieve both high saturation magnetic flux density and low coercivity. Therefore, by using such amorphous alloy soft magnetic powders, it is possible to miniaturize and increase the power output of magnetic elements.

[0016] 1.1.Composition The composition of the amorphous alloy soft magnetic powder will be described in detail below. As mentioned above, the amorphous alloy soft magnetic powder according to the embodiment is (Fe x Co 1-x ) 100-(a+b) (Si y B 1-y ) a M b It has a composition represented by the formula shown. This compositional formula represents the ratio of at least five elements: Fe, Co, Si, B, and M.

[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 is set so that Fe is the main component, i.e., the proportion of atoms is highest, in the amorphous alloy soft magnetic powder. In the amorphous alloy soft magnetic powder according to this embodiment, the Fe content is preferably 61.0% by mass or more and 71.0% by mass or less, more preferably 63.0% by mass or more and 69.0% by mass or less, and even more preferably 65.0% by mass or more and 68.0% by mass or less. If the Fe content falls below the lower limit, the magnetic flux density of the amorphous alloy soft magnetic powder may decrease depending on the composition. On the other hand, if the Fe content exceeds the upper limit, it may become difficult to stably form an amorphous structure depending on the composition.

[0019] x represents the ratio of the number of Fe atoms to the total number of Co atoms, with the sum of the number of Fe atoms and Co atoms being 1. In the amorphous alloy soft magnetic powder according to this embodiment, x is set to 0.73 ≤ x ≤ 0.85. Preferably, it is set to 0.75 ≤ x ≤ 0.83, and more preferably to 0.77 ≤ x ≤ 0.81.

[0020] Co (cobalt) can increase the saturation magnetic flux density of amorphous alloy soft magnetic powders.

[0021] When the sum of the number of Fe atoms and the number of Co atoms is set to 1, the ratio of the number of Co atoms to the total number of atoms is set to 0.15 ≤ 1-x ≤ 0.27. Preferably, it is set to 0.17 ≤ 1-x ≤ 0.25, and more preferably to 0.19 ≤ 1-x ≤ 0.23. By setting 1-x within the above range, it is possible to increase the saturation magnetic flux density of the amorphous alloy soft magnetic powder while suppressing the increase in coercivity.

[0022] Furthermore, if 1-x falls below the lower limit, the Co content becomes too low relative to the Fe content, making it impossible to sufficiently increase the saturation magnetic flux density. On the other hand, if 1-x exceeds the upper limit, the Co content becomes too high relative to the Fe content, making it difficult to stably form an amorphous structure, and thus increasing the coercivity.

[0023] The Co content is preferably 12.0 atomic% to 22.0 atomic%, and more preferably 15.0 atomic% to 19.0 atomic%.

[0024] Silicon (Si) promotes amorphous formation and increases the permeability of amorphous alloy soft magnetic powder when it is manufactured from raw materials. This makes it possible to achieve both low coercivity and high permeability.

[0025] 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 reduction of coercivity and increase of magnetic permeability.

[0026] y represents the ratio of the number of Si atoms to the total number of B atoms, where the sum of the number of Si atoms and the number of B atoms is 1. In the amorphous alloy soft magnetic powder according to this embodiment, y is set to 0.02 ≤ y ≤ 0.10. Preferably, it is set to 0.04 ≤ y ≤ 0.08, and more preferably to 0.05 ≤ y ≤ 0.07. By setting y within the above range, the balance between the number of Si atoms and the number of B atoms can be optimized. This allows for sufficient amorphous formation even with relatively high concentrations of Fe and Co. Therefore, by setting y within the above range, it is possible to achieve low coercivity without impairing a high saturation magnetic flux density.

[0027] Furthermore, if y falls below the lower limit, or if y exceeds the upper limit, the balance between the number of Si atoms and the number of B atoms is disrupted. For this reason, amorphous formation cannot be promoted in composition ratios with relatively high concentrations of Fe and Co.

[0028] a influences the balance between Si and B, and Fe and Co. In the amorphous alloy soft magnetic powder according to this embodiment, a is set to 13.0 ≤ a ≤ 19.0. Preferably, it is set to 14.0 ≤ a ≤ 18.0, and more preferably to 15.0 ≤ a ≤ 17.0. By setting a within the above range, the balance between Si and B, which mainly promote amorphous formation, and Fe and Co, which mainly increase the saturation magnetic flux density, is optimized.

[0029] Furthermore, if a falls below the lower limit, the ratio of Si and B decreases and the ratio of Fe and Co increases, making amorphous formation difficult. On the other hand, if a exceeds the upper limit, the ratio of Si and B increases and the ratio of Fe and Co decreases, making it difficult to sufficiently increase the saturation magnetic flux density.

[0030] The Si content is preferably 0.40 atomic% to 1.80 atomic% and more preferably 0.80 atomic% to 1.50 atomic%.

[0031] The content of B is preferably 11.0 atomic% to 18.0 atomic%, and more preferably 14.0 atomic% to 16.0 atomic%.

[0032] M is at least one element selected from the group consisting of C, S, P, Sn, Mo, Cu, and Nb. By including a predetermined amount of M, the saturation magnetic flux density can be further increased. Furthermore, by including two or more of the above elements as M, the saturation magnetic flux density can be further increased compared to when M is not included or when only one type of M is included.

[0033] b represents the content of M. If M contains multiple elements, b represents the total content of all elements. In the amorphous alloy soft magnetic powder according to this embodiment, b is set to 0 ≤ b ≤ 2.0. Preferably, it is set to 0.5 ≤ b ≤ 1.5, and more preferably to 0.7 ≤ b ≤ 1.2. By setting b within the above range, the saturation magnetic flux density can be increased without inhibiting amorphous formation.

[0034] If b falls below the lower limit, the above effect may not be fully obtained. On the other hand, if b exceeds the upper limit, amorphous formation will be inhibited.

[0035] The amorphous alloy soft magnetic powder according to this embodiment is (Fe x Co 1-x ) 100-(a+b) (Si y B 1-y ) a M b In addition to the composition represented by the formula, impurities may also be present. Examples of impurities include any element other than those listed above, but it is preferable that the total content of impurities be 1.0% by mass or less, more preferably 0.2% by mass or less, and even more preferably 0.1% by mass or less.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] Furthermore, when specifically identifying nitrogen (N) and oxygen (O), 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 and nitrogen analyzer is an example.

[0041] 1.2. Evaluation of powder by XAFS measurement XAFS measurement is performed on the amorphous alloy soft magnetic powder according to the embodiment to obtain an X-ray absorption spectrum. 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 measurement 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.

[0042] 1.2.1. Features (1) In the amorphous alloy soft magnetic powder according to this embodiment, when XAFS measurements are performed on the contained particles, the obtained Si-K absorption edge XANES spectrum has peaks A, B, and C that satisfy the following intensity ratio as characteristic (1).

[0043] When the intensity of peak A, which is in the energy range of 1842±1eV, is denoted as A, the intensity of peak B, which is in the energy range of 1845±1eV, is denoted as B, and the intensity of peak C, which is in the energy range of 1848±1eV, is denoted as C, then the intensity ratio A / C is 0.40 or less, and the intensity ratio B / C is 0.60 or less. The Si-K absorption edge XANES spectrum described above is obtained by setting the depth of the XAFS measurement in the particle to the bulk (depth of several tens of μm). The depth of the XAFS measurement can be controlled from the bulk to the surface (depth of less than several hundred nm) by selecting the signal to be detected in the XAFS measurement. Specifically, when X-rays are selected as the signal to be detected, the measurement depth can be set to the bulk, and when electrons are selected as the signal to be detected, the measurement depth can be set to the surface. In this specification, "peak intensity" refers to the height of the peak in the spectrum or radial distribution function from the background.

[0044] Peak A is a structure attributed to the Fe-Si atom pair. Peak B is also a structure attributed to the Fe-Si atom pair. Peak C is a structure attributed to SiO2.

[0045] 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.

[0046] The fact that the intensity ratio A / C is within the aforementioned range, and that the intensity ratio B / C is within the aforementioned range, supports the low intensity ratio of the peaks attributed to the Fe-Si coordination representing the crystalline state. Therefore, satisfying characteristic (1) indicates a high degree of amorphousness in the particles contained in the amorphous alloy soft magnetic powder. As mentioned above, such amorphous alloy soft magnetic powder achieves low coercivity due to a high degree of amorphousness without compromising the high saturation magnetic flux density caused by the high concentration of added Fe and Co.

[0047] The intensity ratio A / C is preferably 0.35 or less. The intensity ratio B / C is preferably 0.50 or less. While a lower limit does not need to be set, it is preferable that each be 0.10 or higher from the viewpoint of suppressing variation between particles.

[0048] 1.2.2. Characteristics (2) In the amorphous alloy soft magnetic powder according to the embodiment, when XAFS measurements are performed on the contained particles, it is preferable that the radial distribution function obtained by Fourier transforming the resulting Si-K absorption edge EXAFS spectrum has peaks D, E, and F that satisfy the following intensity ratios as characteristic (2).

[0049] When the intensity of peak D, which lies within an interatomic distance of 0.13 ± 0.04 nm, is denoted as D, the intensity of peak E, which lies within an interatomic distance of 0.24 ± 0.04 nm, is denoted as E, and the intensity of peak F, which lies within an interatomic distance of 0.43 ± 0.04 nm, is denoted as F, then the intensity ratio E / D is 0.60 or less, and the intensity ratio F / D is 0.40 or less. Note that the Si-K absorption edge EXAFS spectrum described above is obtained by setting the depth of the XAFS measurement in the particle to the bulk depth.

[0050] Peak D is a structure attributed to an oxygen atom adjacent to the absorbing Si atom (first nearest neighbor oxygen atom). Peak E is a structure attributed to an iron atom adjacent to the Si atom (first nearest neighbor iron atom). Peak F is a structure attributed to an iron atom adjacent to the iron atom adjacent to the first nearest neighbor iron atom (second nearest neighbor iron atom).

[0051] The fact that the intensity ratio E / D and the intensity ratio F / D are within the aforementioned range confirms that the intensity ratio of the peak corresponding to the interatomic distance representing the crystalline state is low. In other words, it can be said that there are relatively many atoms that deviate from the atomic arrangement of the crystalline state. Therefore, satisfying characteristic (2) indicates that the degree of amorphousness is high in the particles contained in the amorphous alloy soft magnetic powder. Thus, amorphous alloy soft magnetic powder that satisfies characteristic (2) will achieve both high saturation magnetic flux density and low coercivity.

[0052] Furthermore, the intensity ratio E / D is more preferably 0.50 or less. Also, the intensity ratio F / D is more preferably 0.30 or less. Although a lower limit does not need to be set, it is preferable that each be 0.01 or higher from the viewpoint of suppressing individual particle variation.

[0053] 1.2.3. Features (3) In the amorphous alloy soft magnetic powder according to the embodiment, when XAFS measurements are performed on the contained particles, it is preferable that the radial distribution function obtained by Fourier transforming the resulting Fe-K absorption edge EXAFS spectrum has peaks G, H, and I that satisfy the following intensity ratios as characteristic (3).

[0054] When the intensity of peak G, which lies within an interatomic distance of 0.22 ± 0.04 nm, is denoted as G, the intensity of peak H, which lies within an interatomic distance of 0.36 ± 0.04 nm, is denoted as H, and the intensity of peak I, which lies within an interatomic distance of 0.45 ± 0.04 nm, is denoted as I, then the intensity ratio H / G is 0.20 or less, and the intensity ratio I / G is 0.20 or less. Note that the Fe-K absorption edge EXAFS spectrum described above is obtained by setting the depth of the XAFS measurement on the particle to the surface.

[0055] Peak G is a structure attributed to the Fe atom adjacent to the absorbing Fe atom (first nearest neighbor Fe atom). Peak H is a structure attributed to the Fe atom adjacent to the first nearest neighbor Fe atom (second nearest neighbor Fe atom). Peak I is a structure attributed to the Fe atom adjacent to the second nearest neighbor Fe atom (third nearest neighbor Fe atom).

[0056] The fact that the intensity ratio H / G and the intensity ratio I / G are within the aforementioned range confirms that the intensity ratio of the peak corresponding to the interatomic distance representing the crystalline state is low. In other words, it can be said that there are relatively many atoms that deviate from the atomic arrangement of the crystalline state. Therefore, satisfying characteristic (3) indicates that the degree of amorphousness is high in the particles contained in the amorphous alloy soft magnetic powder. Thus, amorphous alloy soft magnetic powder that satisfies characteristic (3) will achieve both high saturation magnetic flux density and low coercivity.

[0057] Furthermore, the intensity ratio H / G is more preferably 0.15 or less. Also, the intensity ratio I / G is more preferably 0.15 or less. Although a lower limit does not need to be set, it is preferable that each be 0.01 or higher from the viewpoint of suppressing individual particle variations.

[0058] Furthermore, the intensity ratio I / H is preferably less than 1.00, more preferably 0.90 or less, and even more preferably 0.80 or less. The intensity ratio I / H is the intensity ratio of peak H, which is attributed to the second nearest neighbor Fe atom, to peak I, which is attributed to the third nearest neighbor Fe atom. The fact that this satisfies the above range confirms that the atomic arrangement of the third nearest neighbor Fe atom deviates from the crystalline state compared to that of the second nearest neighbor Fe atom. This indicates a higher degree of amorphousness. Therefore, amorphous alloy soft magnetic powders in which the intensity ratio I / H satisfies the above range will have even lower coercivity.

[0059] Furthermore, it is preferable that the interatomic distance of peak G lies within the aforementioned range, and more preferably within the range of 0.190 nm to 0.205 nm. This interatomic distance is shorter than the interatomic distance in the crystalline state. The presence of peak G within this range confirms that the atomic arrangement of the first nearest neighbor Fe atom is sufficiently deviated from the crystalline state, indicating an even higher degree of amorphousness. Therefore, amorphous alloy soft magnetic powders in which peak G lies within the aforementioned range will have even lower coercivity.

[0060] 1.2.4. Characteristics (4) In the amorphous alloy soft magnetic powder according to the embodiment, when XAFS measurements are performed on the contained particles, it is preferable that the radial distribution function obtained by Fourier transforming the resulting Co-K absorption edge EXAFS spectrum has peaks J, K, and L that satisfy the following intensity ratios as characteristic (4).

[0061] When the intensity of peak J located within the interatomic distance range of 0.22 ± 0.04 nm is denoted as J, the intensity of peak K located within the interatomic distance range of 0.35 ± 0.04 nm is denoted as K, and the intensity of peak L located within the interatomic distance range of 0.44 ± 0.04 nm is denoted as L, then the intensity ratio K / J is 0.20 or less, and the intensity ratio L / J is 0.20 or less. Note that the above-mentioned Co-K absorption edge EXAFS spectrum is obtained by setting the depth of the XAFS measurement on the particle to the surface.

[0062] Peak J is a structure attributed to the Fe atom adjacent to the absorbing Co atom (first nearest neighbor Fe atom). Peak K is a structure attributed to the Fe atom adjacent to the first nearest neighbor Fe atom (second nearest neighbor Fe atom). Peak L is a structure attributed to the Fe atom adjacent to the second nearest neighbor Fe atom (third nearest neighbor Fe atom).

[0063] The fact that the intensity ratio K / J and the intensity ratio L / J are within the aforementioned range confirms that the intensity ratio of the peak corresponding to the interatomic distance representing the crystalline state is low. In other words, it can be said that there are relatively many atoms that deviate from the atomic arrangement of the crystalline state. Therefore, satisfying characteristic (4) indicates that the degree of amorphousness is high on the surface of the particles contained in the amorphous alloy soft magnetic powder. Thus, amorphous alloy soft magnetic powder that satisfies characteristic (4) will achieve both high saturation magnetic flux density and low coercivity.

[0064] Furthermore, the intensity ratio K / J is more preferably 0.15 or less. Also, the intensity ratio L / J is more preferably 0.15 or less. Although a lower limit does not need to be set, it is preferable that each be 0.01 or higher from the viewpoint of suppressing variation between particles.

[0065] Furthermore, the intensity ratio L / K is preferably less than 1.00, more preferably 0.90 or less, and even more preferably 0.80 or less. The intensity ratio L / K is the intensity ratio of the peak K attributed to the second nearest neighbor Fe atom to the peak L attributed to the third nearest neighbor Fe atom. The fact that this satisfies the above range confirms that the atomic arrangement of the third nearest neighbor Fe atom deviates from the crystalline state compared to the second nearest neighbor Fe atom. This indicates a higher degree of amorphousness. Therefore, amorphous alloy soft magnetic powders in which the intensity ratio L / K satisfies the above range will have even lower coercivity.

[0066] Furthermore, it is preferable that the interatomic distance of peak J lies within the aforementioned range, and more preferably within the range of 0.190 nm to 0.205 nm. This interatomic distance is shorter than the interatomic distance in the crystalline state. The presence of peak J within this range confirms that the atomic arrangement of the first nearest neighbor Fe atom is sufficiently deviated from the crystalline state, indicating an even higher degree of amorphousness. Therefore, amorphous alloy soft magnetic powders in which peak J lies within the aforementioned range will have even lower coercivity.

[0067] 1.2.5. Characteristics (5) In the amorphous alloy soft magnetic powder according to the embodiment, when XAFS measurements are performed on the contained particles, it is preferable that the radial distribution function obtained by Fourier transforming the resulting Co-K absorption edge EXAFS spectrum has peaks M, N, and O that satisfy the following intensity ratios as characteristic (5).

[0068] When the intensity of peak M located within the interatomic distance range of 0.20 ± 0.04 nm is denoted as M, the intensity of peak N located within the interatomic distance range of 0.35 ± 0.04 nm is denoted as N, and the intensity of peak O located within the interatomic distance range of 0.45 ± 0.04 nm is denoted as O, then the intensity ratio N / M is 0.20 or less, and the intensity ratio O / M is 0.20 or less. Note that the above-mentioned Co-K absorption edge EXAFS spectrum is obtained by setting the depth of the XAFS measurement in the particle to the bulk depth.

[0069] Peak M is a structure attributed to the Fe atom adjacent to the absorbing Co atom (first nearest neighbor Fe atom). Peak N is a structure attributed to the Fe atom adjacent to the first nearest neighbor Fe atom (second nearest neighbor Fe atom). Peak O is a structure attributed to the Fe atom adjacent to the second nearest neighbor Fe atom (third nearest neighbor Fe atom).

[0070] The fact that the intensity ratio N / M is within the aforementioned range, and that the intensity ratio O / M is within the aforementioned range, supports the idea that the intensity ratio of the peak corresponding to the interatomic distance representing the crystalline state is low. In other words, it supports the idea that there are relatively many atoms that deviate from the atomic arrangement of the crystalline state. Therefore, satisfying characteristic (5) indicates that the degree of amorphousness is high in the bulk of the particles contained in the amorphous alloy soft magnetic powder. Thus, amorphous alloy soft magnetic powder that satisfies characteristic (5) will achieve both high saturation magnetic flux density and low coercivity.

[0071] Furthermore, the intensity ratio N / M is more preferably 0.15 or less. Also, the intensity ratio O / M is more preferably 0.15 or less. Although a lower limit does not need to be set, it is preferable that each be 0.01 or higher from the viewpoint of suppressing individual particle variation.

[0072] Furthermore, the intensity ratio O / N is preferably less than 1.00, more preferably 0.90 or less, and even more preferably 0.80 or less. The intensity ratio O / N is the intensity ratio of peak N, which is attributed to the second nearest neighbor Fe atom, to peak O, which is attributed to the third nearest neighbor Fe atom. The fact that this satisfies the above range confirms that the atomic arrangement of the third nearest neighbor Fe atom deviates from the crystalline state compared to that of the second nearest neighbor Fe atom. This indicates a higher degree of amorphousness. Therefore, amorphous alloy soft magnetic powders in which the intensity ratio O / N satisfies the above range will have even lower coercivity.

[0073] Furthermore, it is preferable that the interatomic distance of peak M lies within the aforementioned range, and more preferably within the range of 0.190 nm to 0.201 nm. This interatomic distance is shorter than the interatomic distance in the crystalline state. The presence of peak M within this range confirms that the atomic arrangement of the first nearest neighbor Fe atom is sufficiently deviated from the crystalline state, indicating an even higher degree of amorphousness. Therefore, amorphous alloy soft magnetic powders in which peak M lies within the aforementioned range will have even lower coercivity.

[0074] 1.3. XAFS Measurement Method XAFS measurements can be performed under the following conditions. • 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. • Beamlines (BLs) and measurement areas used: BL6N1 (for Si-K absorption edge acquisition), BL5S1 (for Fe-K and Co-K absorption edge acquisition) • Angle of incidence on the sample: 20° (when acquiring Si-K absorption edge), 15° (when acquiring Fe-K and Co-K absorption edge) *The above incidence angle is the incidence angle of X-rays with respect to the normal to the sample surface. • Energy calibration: Before acquiring the Si-K absorption edge XANES spectrum, the SK absorption edge XANES spectrum of K2SO4 held by the BL is acquired using total electron yield (TEY) and calibrated so that the peak top is 2481.70 eV. In addition, before performing XAFS measurements for Fe and Co, transmission measurements are performed on Fe-foil and Co-foil 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

[0075] • 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. Next, from the X-ray absorption spectra prepared as described above, the EXAFS spectra of the K absorption edge of Si, Fe, and Co, 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.

[0076] 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.

[0077] Crystallinity = {Crystal-derived strength / (Crystal-derived strength + Amorphous-derived strength)} × 100 Furthermore, as an X-ray diffractometer, for example, the RINT2500V / PC manufactured by Rigaku Corporation is used.

[0078] 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 amorphousization 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 also contain crystalline structures in a volume ratio of, for example, 70% or less.

[0079] The average particle size D50 of the amorphous alloy soft magnetic powder is not particularly limited, but is preferably 5.0 μm to 60.0 μm, more preferably 10.0 μm to 50.0 μm, and even more preferably 20.0 μm to 40.0 μm. By using amorphous alloy soft magnetic powder with such an average particle size, a high compaction density can be obtained. As a result, the packing density of the compacted magnetic core can be increased, and a high saturation magnetic flux density and high permeability can be obtained.

[0080] 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%.

[0081] 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 a sufficient reduction in crystallinity. 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 reducing the packing efficiency during compaction.

[0082] 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 1.5 and 3.5, and more preferably between 2.0 and 3.0. (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 can be obtained that can be used to manufacture compacted magnetic cores with particularly high saturation magnetic flux density.

[0083] The coercivity of the amorphous alloy soft magnetic powder according to the embodiment is set to 24 [A / m] or more (0.3 [Oe] or more) and 199 [A / m] or less (2.5 [Oe] or less), but is preferably 40 [A / m] or more (0.5 [Oe] or more) and 175 [A / m] or less (2.2 [Oe] or less), and more preferably 56 [A / m] or more (0.7 [Oe] or more) and 159 [A / m] or less (2.0 [Oe] or less).

[0084] By using amorphous alloy soft magnetic powder with relatively low coercivity, it is possible to manufacture compacted magnetic cores that can sufficiently suppress hysteresis loss even at high frequencies.

[0085] 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. Moreover, if coercivity is pursued too aggressively, it affects the saturation magnetic flux density, leading to a decrease in saturation magnetic flux density. On the other hand, if the coercivity exceeds the aforementioned upper limit, it increases hysteresis loss at high frequencies, resulting in increased iron loss in the compacted magnetic core.

[0086] 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.

[0087] The saturation magnetic flux density of the amorphous alloy soft magnetic powder according to the embodiment is set to 1.60[T] or more and 2.20[T] or less, but is preferably 1.60[T] or more and 2.10[T] or less, and more preferably 1.65[T] or more and 2.00[T] or less.

[0088] By using amorphous alloy soft magnetic powder with a relatively high saturation magnetic flux density, a compacted magnetic core with a high saturation magnetic flux density can be obtained. Such a compacted magnetic core allows for miniaturization and increased power output of magnetic elements.

[0089] Furthermore, if the saturation magnetic flux density falls below the aforementioned lower limit, it becomes difficult to miniaturize and increase the output of the magnetic element. On the other hand, if the saturation magnetic flux density exceeds the aforementioned upper limit, it becomes difficult to stably manufacture amorphous alloy soft magnetic powder with such a saturation magnetic flux density. Moreover, pursuing the saturation magnetic flux density too much affects the coercivity, leading to an increase in coercivity.

[0090] 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

[0091] The permeability of the amorphous alloy soft magnetic powder according to this embodiment is preferably 20.0 or higher, and more preferably 21.0 or higher, at a measurement frequency of 100 kHz. Such amorphous alloy soft magnetic powder contributes to the realization of compacted magnetic cores with high saturation magnetic flux density, meaning that the magnetic flux density does not easily saturate even when a high magnetic field is applied. The upper limit of the permeability is not particularly limited, but considering stable manufacturing, it is set to 50.0 or lower.

[0092] 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.

[0093] In amorphous alloy soft magnetic powder, 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 of the compacted magnetic core can be particularly increased.

[0094] The apparent density of amorphous alloy soft magnetic powder is 4.55 [g / cm³]. 3 ] or more than 4.80[g / cm 3 Preferably, 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:

[0095] 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:

[0096] By having the apparent density and tap density of the amorphous alloy soft magnetic powder within the aforementioned range, the saturation magnetic flux density of the compacted magnetic core can be particularly increased.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 1.5. Effects of the Embodiment As described above, the amorphous alloy soft magnetic powder according to the embodiment is (Fe x Co 1-x ) 100-(a+b) (Si y B 1-y ) a M b The composition is represented by [M is at least one selected from the group consisting of C, S, P, Sn, Mo, Cu, and Nb, and x, y, a, and b are 0.73 ≤ x ≤ 0.85, 0.02 ≤ y ≤ 0.10, 13.0 ≤ a ≤ 19.0, and 0 ≤ b ≤ 2.0]. When an amorphous alloy soft magnetic powder having the above composition is subjected to XAFS measurement with the analysis depth set to bulk, the resulting Si-K absorption edge XANES spectrum has peaks A, B, and C that satisfy the following intensity ratios. When the intensity of peak A, which has an energy within the range of 1842±1eV, is denoted as A, the intensity of peak B, which has an energy within the range of 1845±1eV, is denoted as B, and the intensity of peak C, which has an energy within the range of 1848±1eV, is denoted as C, then the intensity ratio A / C is 0.40 or less, and the intensity ratio B / C is 0.60 or less.

[0101] By satisfying this range of intensity ratios, the particles contained in the amorphous alloy soft magnetic powder have a high degree of amorphousness. Therefore, an amorphous alloy soft magnetic powder can be obtained that has low coercivity due to a high degree of amorphousness without compromising the high saturation magnetic flux density caused by the high concentration of added Fe and Co. In other words, an amorphous alloy soft magnetic powder can be obtained that achieves both high saturation magnetic flux density and low coercivity.

[0102] Furthermore, in the amorphous alloy soft magnetic powder according to this embodiment, the radial distribution function obtained by Fourier transforming the Si-K absorption edge EXAFS spectrum obtained by performing an XAFS measurement with the analysis depth set to bulk has peaks D, E, and F that satisfy the following intensity ratios. When the intensity of peak D, which is located within the range of interatomic distance 0.13 ± 0.04 nm, is denoted as D, the intensity of peak E, which is located within the range of interatomic distance 0.24 ± 0.04 nm, is denoted as E, and the intensity of peak F, which is located within the range of interatomic distance 0.43 ± 0.04 nm, is denoted as F, then the intensity ratio E / D is 0.60 or less, and the intensity ratio F / D is 0.40 or less.

[0103] By satisfying this range of intensity ratios, the particles contained in the amorphous alloy soft magnetic powder have a high degree of amorphousness. Therefore, an amorphous alloy soft magnetic powder that achieves both high saturation magnetic flux density and low coercivity can be obtained.

[0104] Furthermore, in the amorphous alloy soft magnetic powder according to this embodiment, the radial distribution function obtained by Fourier transforming the Fe-K absorption edge EXAFS spectrum obtained by performing an XAFS measurement with the analysis depth set to the surface has peaks G, H, and I that satisfy the following intensity ratios. When the intensity of peak G, which is located within the range of interatomic distances of 0.22 ± 0.04 nm, is denoted as G, the intensity of peak H, which is located within the range of interatomic distances of 0.36 ± 0.04 nm, is denoted as H, and the intensity of peak I, which is located within the range of interatomic distances of 0.45 ± 0.04 nm, is denoted as I, then the intensity ratio H / G is 0.20 or less, and the intensity ratio I / G is 0.20 or less.

[0105] By satisfying this range of intensity ratios, the particles contained in the amorphous alloy soft magnetic powder have a high degree of amorphousness. Therefore, an amorphous alloy soft magnetic powder that achieves both high saturation magnetic flux density and low coercivity can be obtained.

[0106] Furthermore, it is preferable that peak G exists within the range of interatomic distance between 0.190 nm and 0.205 nm. This results in particles containing amorphous alloy soft magnetic powder having a particularly high degree of amorphousness.

[0107] Furthermore, in the amorphous alloy soft magnetic powder according to this embodiment, the radial distribution function obtained by Fourier transforming the Co-K absorption edge EXAFS spectrum obtained by performing an XAFS measurement with the analysis depth set to the surface has peaks J, K, and L that satisfy the following intensity ratios. When the intensity of peak J located within the interatomic distance range of 0.22 ± 0.04 nm is denoted as J, the intensity of peak K located within the interatomic distance range of 0.35 ± 0.04 nm is denoted as K, and the intensity of peak L located within the interatomic distance range of 0.44 ± 0.04 nm is denoted as L, then the intensity ratio K / J is 0.20 or less, and the intensity ratio L / J is 0.20 or less.

[0108] By satisfying this range of intensity ratios, the particles contained in the amorphous alloy soft magnetic powder have a high degree of amorphousness. Therefore, an amorphous alloy soft magnetic powder that achieves both high saturation magnetic flux density and low coercivity can be obtained.

[0109] Furthermore, it is preferable that peak J is located within the range of interatomic distance between 0.190 nm and 0.205 nm. This results in particles containing amorphous alloy soft magnetic powder having a particularly high degree of amorphousness.

[0110] Furthermore, in the amorphous alloy soft magnetic powder according to this embodiment, the radial distribution function obtained by Fourier transforming the Co-K absorption edge EXAFS spectrum obtained by performing an XAFS measurement with the analysis depth set to bulk has a peak M located in the range of 0.190 nm to 0.201 nm in terms of interatomic distance. As a result, the particles contained in the amorphous alloy soft magnetic powder have a particularly high degree of amorphousness.

[0111] 2. Method for producing amorphous alloy soft magnetic powder Next, we will describe a method for producing amorphous alloy soft magnetic powder.

[0112] Amorphous alloy soft magnetic powder may be manufactured by any method, for example, by atomization methods such as water atomization, gas atomization, and rotary water flow atomization, as well as by various powdering methods such as reduction, carbonylation, and pulverization.

[0113] 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 produced 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. By using such an atomization method, amorphous alloy soft magnetic powder with good amorphous properties and excellent packing properties can be efficiently produced.

[0114] 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.

[0115] 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 formation.

[0116] 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 production of amorphous alloy soft magnetic powder with sufficient amorphous properties. In other words, amorphous properties can be achieved even with compositions that have relatively high Fe and Co content. In particular, the rotating water flow atomization method yields 10 7 Cooling speeds of [K / sec] or higher can be easily achieved.

[0117] The following describes the method for producing amorphous alloy soft magnetic powder using the rotary water atomization method.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] In the rotary water atomization method, a very high cooling rate can be stably maintained by continuously supplying the cooling liquid, thereby promoting the amorphous formation of the amorphous alloy soft magnetic powder produced.

[0129] 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.

[0130] 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, making it possible to efficiently produce amorphous alloy soft magnetic powder with sufficient amorphous properties. Furthermore, the cooling rate of molten metal 25 per unit amount can be increased, thereby increasing the degree of amorphous properties.

[0131] 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, making it possible to produce amorphous alloy soft magnetic powder with sufficient amorphous properties. 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 amorphous properties. 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 amorphous properties.

[0132] 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].

[0133] 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.

[0134] 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.

[0135] 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.

[0136] Furthermore, the amorphous alloy soft magnetic powder may be subjected to heat treatment as needed after manufacturing. For example, the heat treatment conditions may include a heating temperature of 200°C to 500°C, with a holding time of 5 minutes to 2 hours. The heat treatment atmosphere may include, for example, an inert gas atmosphere such as nitrogen or argon, a reducing gas atmosphere such as hydrogen or ammonia decomposition gas, or a reduced-pressure atmosphere of these gases.

[0137] 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.

[0138] 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.

[0139] 3. Compacted magnetic cores and magnetic elements Next, the powdered magnetic core and magnetic element according to the embodiment will be described.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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 a high saturation magnetic flux density 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.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] The following describes closed-circuit type coil components, focusing on the differences from toroidal type coil components, and omitting explanations of similar aspects.

[0151] 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 a high saturation magnetic flux density and low coercivity.

[0152] 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.

[0153] Furthermore, the compacted magnetic core 21 may, if necessary, contain soft magnetic powders or non-magnetic powders other than the amorphous alloy soft magnetic powder described in the embodiment above.

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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).

[0158] 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.

[0159] 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.

[0160] 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.

[0161] 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 low coercivity and high saturation magnetic flux density, to be enjoyed, enabling miniaturization and increased output of electronic devices.

[0162] Although 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, the present invention is not limited thereto.

[0163] For example, in the above embodiment, a compacted magnetic core was described as an example of an application of the amorphous alloy soft magnetic powder of the present invention, but the examples of applications are not limited to this, and may also be magnetic devices such as magnetic fluids, magnetic shielding sheets, and magnetic heads. Furthermore, 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]

[0164] 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 [ / min], the coolant pressure was set to 40 MPa.

[0165] 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.

[0166] Next, the obtained amorphous alloy soft magnetic powder was subjected to particle size distribution measurement. This measurement was performed using a laser diffraction particle size distribution analyzer, the Microtrac HRA9320-X100, manufactured by Nikkiso Co., Ltd. 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 1.

[0167] Next, the obtained amorphous alloy soft magnetic powder was heated in a nitrogen atmosphere at 360°C for 15 minutes.

[0168] 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.

[0169] 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.

[0170] Next, the obtained granulated powder was filled into a mold, and a molded body was obtained based on the following molding conditions.

[0171] <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)

[0172] 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.

[0173] 5.2. Samples No. 2-16 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. 1.

[0174] [Table 1]

[0175] 5.3. Samples No. 17-29 Except for using the amorphous alloy soft magnetic powders shown in Table 2, compacted magnetic cores were obtained in the same manner as Sample No. 1.

[0176] 5.4. Sample No. 30 Amorphous alloy soft magnetic powder was manufactured and compacted magnetic cores were obtained in the same manner as in Sample No. 1, except that the water atomization method was used instead of the rotary water flow atomization method. The cooling rates by the water atomization method are shown in Table 2.

[0177] 5.5. Sample No. 31 A compacted magnetic core was obtained in the same manner as for Sample No. 30, except that the amorphous alloy soft magnetic powder shown in Table 2 was used.

[0178] [Table 2]

[0179] In Tables 1 and 2, 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."

[0180] 6. Evaluation of amorphous alloy soft magnetic powder and compacted magnetic cores 6.1. XAFS Measurement of Amorphous Alloy Soft Magnetic Powder XAFS measurements were performed on amorphous alloy soft magnetic powders, specifically Sample No. 3 (Example) and Sample No. 30 (Comparative Example), which represent the amorphous alloy soft magnetic powders obtained in each example and comparative example. The measurement results are shown in Figures 7 to 16.

[0181] 6.1.1. Si-K Absorption Edge XANES Spectra Figure 7 shows the Si-K absorption edge XANES spectra obtained for amorphous alloy soft magnetic powders of Sample No. 3 (Example) and Sample No. 30 (Comparative Example). Figure 8 is a graph comparing the intensity ratios A / C and B / C obtained from the Si-K absorption edge XANES spectra shown in Figure 7.

[0182] As shown in Figure 7, peaks A and B have a shoulder structure, and peak C has an upward convex shape. The heights of these peaks were obtained, and the intensity ratios A / C and B / C were calculated. Similarly, the intensity ratios A / C and B / C were calculated for amorphous alloy soft magnetic powders of other examples and comparative examples. The calculation results are shown in Tables 3 and 4.

[0183] As shown in Figure 8, in Sample No. 3 (Example), the intensity ratio A / C was 0.40 or less, and the intensity ratio B / C was 0.60 or less. In contrast, in Sample No. 30 (Comparative Example), both the intensity ratio A / C and the intensity ratio B / C were outside the above ranges.

[0184] 6.1.2. Radial distribution function based on Si-K absorption edge EXAFS spectrum Figure 9 shows the radial distribution function based on the Si-K absorption edge EXAFS spectra obtained for amorphous alloy soft magnetic powders of Sample No. 3 (Example) and Sample No. 30 (Comparative Example). Figure 10 is a graph comparing the intensity ratios E / D and F / D obtained from the radial distribution function shown in Figure 9.

[0185] As shown in Figure 9, peaks D, E, and F were observed in the radial distribution function. The heights of these peaks were obtained, and the intensity ratios E / D and F / D were calculated. Similarly, the intensity ratios E / D and F / D were calculated for amorphous alloy soft magnetic powders of other examples and comparative examples. The calculation results are shown in Tables 3 and 4.

[0186] As shown in Figure 10, in Sample No. 3 (Example), the intensity ratio E / D was 0.60 or less, and the intensity ratio F / D was 0.40 or less. In contrast, in Sample No. 30 (Comparative Example), the intensity ratios E / D and F / D were outside the above ranges.

[0187] 6.1.3. Radial distribution function based on Fe-K absorption edge EXAFS spectrum Figure 11 shows the radial distribution function based on the Fe-K absorption edge EXAFS spectra obtained for amorphous alloy soft magnetic powders of Sample No. 3 (Example) and Sample No. 30 (Comparative Example). Figure 12 is a graph comparing the intensity ratios H / G and I / G obtained from the radial distribution function shown in Figure 11. Figures 11 and 12 also include the measurement results for the reference sample, Fe-foil.

[0188] As shown in Figure 11, peaks G, H, and I were observed in the radial distribution function. The position of peak G was within the range of interatomic distance between 0.190 nm and 0.205 nm. The heights of these peaks were obtained, and the intensity ratios H / G and I / G were calculated. Similarly, the intensity ratios H / G and I / G were calculated for amorphous alloy soft magnetic powders of other examples and comparative examples. The calculation results are shown in Tables 3 and 4.

[0189] As shown in Figure 12, in Sample No. 3 (Example), the intensity ratio H / G was 0.20 or less, and the intensity ratio I / G was 0.20 or less. In contrast, in Sample No. 30 (Comparative Example) and Fe-foil, the intensity ratios H / G and I / G were outside the above ranges.

[0190] 6.1.4. Radial distribution function (surface) based on Co-K absorption edge EXAFS spectrum Figure 13 shows the radial distribution function based on the Co-K absorption edge EXAFS spectra obtained for the surface of amorphous alloy soft magnetic powders of Sample No. 3 (Example) and Sample No. 30 (Comparative Example). Figure 14 is a graph comparing the intensity ratios K / J and L / J obtained from the radial distribution function shown in Figure 13. Figures 13 and 14 also include the measurement results for the reference sample, Fe-foil.

[0191] As shown in Figure 13, peaks J, K, and L were observed in the radial distribution function. The position of peak J was within the range of interatomic distance between 0.190 nm and 0.205 nm. The heights of these peaks were obtained, and the intensity ratios K / J and L / J were calculated. Similarly, the intensity ratios K / J and L / J were calculated for amorphous alloy soft magnetic powders of the other examples and comparative examples, with some exceptions. The calculation results are shown in Tables 3 and 4.

[0192] As shown in Figure 14, in Sample No. 3 (Example), the strength ratio K / J was 0.20 or less, and the strength ratio L / J was 0.20 or less. In contrast, in Sample No. 30 (Comparative Example) and Fe-foil, the strength ratios K / J and L / J were outside the above ranges.

[0193] 6.1.5. Radial distribution function (bulk) based on Co-K absorption edge EXAFS spectrum Figure 15 shows the radial distribution function based on the Co-K absorption edge EXAFS spectra obtained for bulk amorphous alloy soft magnetic powders of Sample No. 3 (Example) and Sample No. 30 (Comparative Example). Figure 16 is a graph comparing the intensity ratio N / M and intensity ratio O / M obtained from the radial distribution function shown in Figure 15. Figures 15 and 16 also include the measurement results for the reference sample, Fe-foil.

[0194] As shown in Figure 15, peaks M, N, and O were observed in the radial distribution function. The position of peak M was within the range of interatomic distance between 0.190 nm and 0.201 nm. The heights of these peaks were obtained, and the intensity ratios N / M and O / M were calculated. Similarly, the intensity ratios N / M and O / M were calculated for amorphous alloy soft magnetic powders of the other examples and comparative examples, with some exceptions. The calculation results are shown in Tables 3 and 4.

[0195] As shown in Figure 16, in Sample No. 3 (Example), the intensity ratio N / M was 0.20 or less, and the intensity ratio O / M was 0.20 or less. In contrast, in Sample No. 30 (Comparative Example) and Fe-foil, the intensity ratio N / M and intensity ratio O / M were outside the above ranges.

[0196] [Table 3]

[0197] [Table 4]

[0198] As is clear from Tables 3 and 4, amorphous alloy soft magnetic powders in which the intensity ratio of the peaks in the XANES spectrum and the intensity ratio of the peaks in the radial distribution function are within a predetermined range were found to have a sufficiently low degree of crystallinity (sufficiently high degree of amorphousness). Furthermore, it was confirmed that such amorphous alloy soft magnetic powders can be manufactured by a manufacturing method involving a high cooling rate.

[0199] 6.2. Powder properties of amorphous alloy soft magnetic powders The apparent density AD and tap density TD were measured for the amorphous alloy soft magnetic powders obtained in each example and comparative example. Furthermore, the relative value of the tap density TD, i.e., the ratio of tap density to apparent density, was calculated, with the apparent density AD set to 100. The measurement and calculation results are shown in Tables 5 and 6.

[0200] 6.3 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 Tables 5 and 6.

[0201] 6.4. Saturated magnetic flux density of amorphous alloy soft magnetic powder For each example and comparative example, the amorphous alloy soft magnetic powder was measured for maximum magnetization, and the saturation magnetic flux density was calculated based on the measurement results. The calculation results are shown in Tables 5 and 6.

[0202] 6.5. Permeability of a compacted magnetic core The permeability of the compacted magnetic cores obtained in each example and comparative example was measured. The measurement results are shown in Tables 5 and 6.

[0203] [Table 5]

[0204] [Table 6]

[0205] As is clear from Tables 5 and 6, the amorphous alloy soft magnetic powders obtained in each example were found to achieve both high saturation magnetic flux density and low coercivity.

[0206] From the above, it was found that by optimizing the intensity ratio of the peaks in the XANES spectrum, it is possible to achieve both high saturation magnetic flux density and low coercivity in amorphous alloy soft magnetic powders.

[0207] Similarly, it was found that by optimizing the peak position and intensity ratio of the radial distribution function obtained from the EXAFS spectrum, it is possible to achieve both high saturation magnetic flux density and low coercivity in amorphous alloy soft magnetic powders. [Explanation of symbols]

[0208] 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. A step of melting raw materials to obtain molten metal, The process involves obtaining amorphous alloy soft magnetic powder by pulverizing the molten metal using a rotating water atomization method while cooling and solidifying it, It has, The amorphous alloy soft magnetic powder is (Fe ｘ Co １－ｘ ) １００－（ａ＋ｂ） (Si ｙ B １－ｙ ) ａ M ｂ [M is at least one selected from the group consisting of C, S, P, Sn, Mo, Cu, and Nb, x, y, a, and b are, 0.73 ≤ x ≤ 0.85, 0.02 ≤ y ≤ 0.10, 13.0 ≤ a ≤ 19.0, 0 ≤ b ≤ 2.

0. Having a composition represented by, The average particle size D50 is 10.0 μm or more and 60.0 μm or less. When XAFS measurements are performed with the analysis depth for particles set to bulk, the obtained Si-K absorption edge XANES spectrum is: Peak A, whose energy is within the range of 1842 ± 1 eV, Peak B, whose energy is within the range of 1845 ± 1 eV, Peak C, whose energy is within the range of 1848 ± 1 eV, It has, Let the intensity of the aforementioned peak A be A. Let the intensity of the aforementioned peak B be B. When the intensity of the aforementioned peak C is denoted as C, The intensity ratio A / C is 0.40 or less. A method for producing amorphous alloy soft magnetic powder, characterized by having an intensity ratio B / C of 0.60 or less.

2. The radial distribution function obtained by performing an XAFS measurement on the amorphous alloy soft magnetic powder with the analysis depth set to bulk, and then performing a Fourier transform on the Si-K absorption edge EXAFS spectrum, is: Peak D, where the interatomic distance is within the range of 0.13 ± 0.04 nm, Peak E, which lies within the range of 0.24 ± 0.04 nm in interatomic distance, Peak F, which lies within the range of 0.43 ± 0.04 nm in interatomic distance, It has, Let D be the intensity of the aforementioned peak D. Let E be the intensity of the aforementioned peak E. When the intensity of the aforementioned peak F is denoted as F, The intensity ratio E / D is 0.60 or less. A method for producing amorphous alloy soft magnetic powder according to claim 1, wherein the strength ratio F / D is 0.40 or less.

3. The radial distribution function obtained by performing an XAFS measurement on the amorphous alloy soft magnetic powder with the analysis depth set to the surface and then performing a Fourier transform on the Fe-K absorption edge EXAFS spectrum is: Peak G, which lies within the range of 0.22 ± 0.04 nm in interatomic distances, Peak H, which is located within the range of 0.36 ± 0.04 nm in interatomic distance, Peak I, where the interatomic distance is within the range of 0.45 ± 0.04 nm, It has, Let G be the intensity of the aforementioned peak G. Let H be the intensity of the aforementioned peak H. When the intensity of the aforementioned peak I is denoted as I, The intensity ratio H / G is 0.20 or less. A method for producing amorphous alloy soft magnetic powder according to claim 1 or 2, wherein the strength ratio I / G is 0.20 or less.

4. The method for producing amorphous alloy soft magnetic powder according to claim 3, wherein the peak G is located within the range of 0.190 nm to 0.205 nm in terms of interatomic distance.

5. The radial distribution function obtained by performing an XAFS measurement on the amorphous alloy soft magnetic powder with the analysis depth set to the surface and then performing a Fourier transform on the Co-K absorption edge EXAFS spectrum is: Peak J, which lies within the range of 0.22 ± 0.04 nm for interatomic distances, Peak K, which lies within the range of 0.35 ± 0.04 nm in interatomic distance, Peak L, where the interatomic distance is within the range of 0.44 ± 0.04 nm, It has, Let J be the intensity of the aforementioned peak J. Let K be the intensity of the aforementioned peak K. When the intensity of the aforementioned peak L is L, The intensity ratio K / J is 0.20 or less. A method for producing amorphous alloy soft magnetic powder according to any one of claims 1 to 4, wherein the strength ratio L / J is 0.20 or less.

6. The method for producing amorphous alloy soft magnetic powder according to claim 5, wherein the peak J is located within the range of 0.190 nm to 0.205 nm in terms of interatomic distance.

7. A method for producing amorphous alloy soft magnetic powder according to any one of claims 1 to 6, wherein the radial distribution function obtained by performing an XAFS measurement on the amorphous alloy soft magnetic powder with the analysis depth set to bulk, and obtaining a Co-K absorption edge EXAFS spectrum, has a peak M located in the range of 0.190 nm to 0.201 nm at the interatomic distance.

8. The rotating water flow atomization method comprises a process of blowing a gas jet onto the molten metal that has been flowed down to pulverize it, and then incorporating it into a cooling liquid layer to cool and solidify it, A method for producing amorphous alloy soft magnetic powder according to any one of claims 1 to 7, wherein the flow rate of the molten metal is greater than 1.0 kg / min and less than or equal to 20.0 kg / min, and the flow rate of the gas jet is 1.0 Nm³ / min or more and less than or equal to 20.0 Nm³ / min.

9. A method for producing amorphous alloy soft magnetic powder according to any one of claims 1 to 8, wherein when the apparent density [g / cm³] of the amorphous alloy soft magnetic powder is set to 100, the tap density [g / cm³] of the amorphous alloy soft magnetic powder is 103 or more and 120 or less.

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