Method for producing soft magnetic alloy powder, soft magnetic alloy powder, powder magnetic core, magnetic element, and electronic device

Abstract

The present invention relates to a method for producing a soft magnetic alloy powder, a soft magnetic alloy powder, a powder magnetic core, a magnetic element, and an electronic device. Provided are a soft magnetic alloy powder having a low coercive force, a method for producing the soft magnetic alloy powder capable of stably producing the soft magnetic alloy powder, a powder magnetic core containing the soft magnetic alloy powder, a magnetic element provided with the powder magnetic core, and an electronic device provided with the magnetic element. A method for producing a soft magnetic alloy powder, said soft magnetic alloy powder being produced from FexCuaNbb (Si1-yBy) 100-x-a-b [wherein 0.3 < = a < = 2.0, 2.0 < = b < = 4.0, and 72.5 < = x < 75.5 are satisfied. And y is a number satisfying f (x) < = y < = 0.99, f (x) = (4 * 10-34) x 17.56. A step for producing an amorphous alloy powder having an average particle diameter of from 10.0 [mu] m to 45.0 [mu] m (inclusive); and a step for producing a soft magnetic alloy powder containing 30 vol% or more of crystal grains of 1.0 nm or more and 30.0 nm or less by heating at 500 DEG C or more and 600 DEG C or less, the volume resistivity of the compact being 10.0 * 10-3 [Omega * cm] or less.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing soft magnetic alloy powder, soft magnetic alloy powder, compacted powder core, magnetic element, and electronic device. Background Art

[0002] Patent Document 1 discloses soft magnetic powder containing amorphous metal particles, the amorphous metal particles having a composition represented by the formula Fe 100-a-b-c-d-e-f-g Cr a Si b B c C d Al e Ti f Co g [wherein, a, b, c, d, e, f, and g are numbers representing atomic %, satisfying 0 < a ≤ 3.0, 5.0 ≤ b ≤ 15.0, 7.0 ≤ c ≤ 15.0, 0.1 ≤ d ≤ 3.0, 0 < e ≤ 0.016, 0 < f ≤ 0.009, 0 ≤ g ≤ 0.025.] By such a configuration, soft magnetic powder having good magnetic properties brought about by the amorphous alloy and achieving low coercivity can be obtained.

[0003] In addition, Patent Document 1 discloses performing heat treatment in the manufacture of soft magnetic powder. By performing heat treatment, various defects or anisotropies (stress-induced anisotropy) introduced during the manufacture of soft magnetic powder can be reduced. Thereby, low coercivity can be achieved. Further, Patent Document 1 discloses that the heating temperature during heat treatment is a temperature lower than the crystallization temperature of the amorphous metal particles.

[0004] Prior Art Documents

[0005] Patent Document

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022 - 175110 Summary of the Invention

[0007] Technical Problem to be Solved by the Invention

[0008] However, from the viewpoint of reliably achieving further low coercivity, there is still room for improvement in the method for manufacturing the soft magnetic powder described in Patent Document 1. For example, even when heat treatment is performed, there are cases where the coercivity of some particles is not sufficiently reduced. Therefore, in order to more reliably reduce the coercivity without sacrificing the manufacturing efficiency of the soft magnetic powder, improvement of the manufacturing method has become a technical problem.

[0009] Technical Solution for Solving the Technical Problem

[0010] A method for manufacturing soft magnetic alloy powder according to an application example of the present invention includes:

[0011] A powder manufacturing step of manufacturing amorphous alloy powder having a composition represented by an atomic ratio formula Fe x Cu a Nb b (Si 1-y B y ) 100-x-a-b [where a, b, and x satisfy 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, and 72.5 ≤ x < 75.5. Additionally, y is a number that satisfies f(x) ≤ y ≤ 0.99, and f(x) = (4 × 10 -34 )x 17.56 .], and an impurity composition, and having an average particle size of 10.0 μm or more and 45.0 μm or less; and

[0012] A heat treatment step of crystallizing the amorphous alloy powder by performing a heat treatment of heating the amorphous alloy powder at a temperature of 500°C or more and 600°C or less to manufacture soft magnetic alloy powder containing 30% by volume or more of crystal grains having a crystal grain size of 1.0 nm or more and 30.0 nm or less,

[0013] When the soft magnetic alloy powder is pressed under a pressure of 63.7 MPa to produce a compact having a mass of 7.0 g, the volume resistivity of the compact is 10.0 × 10 -3 [Ω·cm] or less.

[0014] The soft magnetic alloy powder according to the application example of the present invention,

[0015] has a composition represented by an atomic ratio formula Fe x Cu a Nb b (Si 1-y B y ) 100-x-a-b [where a, b, and x are numbers in atomic %, and satisfy 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, and 72.5 ≤ x < 75.5. Additionally, y is a number that satisfies f(x) ≤ y ≤ 0.99, and f(x) = (4 × 10 -34 )x 17.56 .], and an impurity composition,

[0016] has an average particle size of 10.0 μm or more and 45.0 μm or less,

[0017] contains 30% by volume or more of crystal grains having a crystal grain size of 1.0 nm or more and 30.0 nm or less,

[0018] When pressing under a pressure of 63.7 MPa to produce a compact powder body with a mass of 7.0 g, the volume resistivity of the compact powder body is 10.0×10 -3 [Ω·cm] or less.

[0019] The compacted powder core according to the application example of the present invention,

[0020] contains the soft magnetic alloy powder according to the application example of the present invention.

[0021] The magnetic element according to the application example of the present invention,

[0022] includes the compacted powder core according to the application example of the present invention.

[0023] The electronic device according to the application example of the present invention,

[0024] includes the magnetic element according to the application example of the present invention. Description of the Drawings

[0025] Figure 1 is a diagram showing regions A to C representing the composition of the soft magnetic alloy powder according to the embodiment in a two-axis orthogonal coordinate system with x as the horizontal axis and y as the vertical axis.

[0026] Figure 2 is a process diagram showing the configuration of the manufacturing method of the soft magnetic alloy powder according to the embodiment.

[0027] Figure 3 is a top view schematically showing a ring-shaped coil component.

[0028] Figure 4 is a perspective three-dimensional view schematically showing a closed magnetic circuit type coil component.

[0029] Figure 5 is a three-dimensional view showing a mobile personal computer as an electronic device including the magnetic element according to the embodiment.

[0030] Figure 6 is a top view showing a smartphone as an electronic device including the magnetic element according to the embodiment.

[0031] Figure 7 is a three-dimensional view showing a digital camera as an electronic device including the magnetic element according to the embodiment.

[0032] Description of the Reference Numerals

[0033] 10: Coil component; 11: Compacted powder core; 12: Conductive wire; 20: Coil component; 21: Compacted powder core; 22: Conductive wire; 100: Display unit; 1000: Magnetic component; 1100: Personal computer; 1102: Keyboard; 1104: Main body; 1106: Display unit; 1200: Smart phone; 1202: Operation button; 1204: Earphone; 1206: Microphone; 1300: Digital camera; 1302: Housing; 1304: Light receiving unit; 1306: Shutter button; 1308: Memory; A: Area; B: Area; C: Area; S102: Powder manufacturing process; S104: Heat treatment process. Detailed Description of the Invention

[0034] Hereinafter, based on the preferred embodiments shown in the drawings, a method for manufacturing a soft magnetic alloy powder, a soft magnetic alloy powder, a compacted powder core, a magnetic component, and an electronic device according to the present invention will be described in detail.

[0035] 1. Soft Magnetic Alloy Powder

[0036] First, the soft magnetic alloy powder according to the embodiment will be described.

[0037] The soft magnetic alloy powder can be applied to any use, for example, for manufacturing a compacted powder core. The compacted powder core is manufactured by molding while bonding particles of the soft magnetic alloy powder to each other.

[0038] The soft magnetic alloy powder according to the embodiment has a composition formula Fe x Cu a Nb b (Si 1- y B y ) 100-x-a-b and impurities in terms of atomic ratio.

[0039] a, b, and x satisfy 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, and 72.5 ≤ x < 75.5. In addition, y is a number that satisfies f(x) ≤ y ≤ 0.99, and f(x) = (4 × 10 -34 )x 17.56 .

[0040] In addition, the average particle size of the soft magnetic alloy powder according to the embodiment is 10.0 μm or more and 45.0 μm or less.

[0041] Furthermore, the soft magnetic alloy powder according to the embodiment contains 30% by volume or more of crystal grains having a crystal grain size of 1.0 nm or more and 30.0 nm or less. These crystal grains are formed by heat-treating an amorphous alloy powder as a precursor under specified conditions during the manufacture of the soft magnetic alloy powder to crystallize it.

[0042] The soft magnetic alloy powder formed by such heat treatment is a powder with a volume resistivity of 10.0×10 -3 [Ω·cm] or less when a compact with a mass of 7.0 g is produced by pressing under a pressure of 63.7 MPa.

[0043] By making the volume resistivity of the compact fall within the above range, soft magnetic alloy powder with a low coercive force can be obtained. In addition, when the volume resistivity of the above compact is within the above range, the deviation of the coercive force of the soft magnetic alloy powder can be suppressed. That is, the soft magnetic alloy powder whose volume resistivity of the above compact is configured within the above range has, for example, homogeneity in which the deviation of each measured value is suppressed to a small extent when divided into multiple particle groups and the coercive force is measured separately. In other words, such soft magnetic alloy powder can be said to be a powder in which the effect of heat treatment is stably enjoyed in each particle, achieving a low coercive force. Therefore, by using this soft magnetic alloy powder to manufacture products such as powder cores, products with stable characteristics can be manufactured with less individual variation.

[0044] 1.1. Composition

[0045] Hereinafter, the composition of the soft magnetic alloy powder will be described in detail. As described above, the soft magnetic alloy powder according to the embodiment has a composition represented by the compositional formula Fe x Cu a Nb b (Si 1-y B y ) 100-x-a-b This compositional formula represents the ratio of the number of atoms in the composition composed of five elements: Fe, Cu, Nb, Si, and B.

[0046] Fe (iron) has a great influence on the basic magnetic properties and mechanical properties of the soft magnetic alloy powder according to the embodiment.

[0047] The content x of Fe is 72.5 atomic% or more and less than 75.5 atomic%, preferably 72.8 atomic% or more and 75.0 atomic% or less, and more preferably 73.0 atomic% or more and 74.5 atomic% or less. It should be noted that when the content x of Fe is lower than the above lower limit value, the saturation magnetic flux density of the soft magnetic alloy powder may decrease. On the other hand, when the content x of Fe is higher than the above upper limit value, it is impossible to stably form an amorphous structure when manufacturing the soft magnetic alloy powder, so it may be difficult to form fine grains with the aforementioned small particle size. In addition, the coercive force of the soft magnetic alloy powder may increase.

[0048] When manufacturing the soft magnetic alloy powder involved in the implementation method from raw materials, Cu (copper) has a tendency to separate from Fe. Therefore, fluctuations occur in the composition due to the inclusion of Cu, and regions prone to partial crystallization are generated in the particles. As a result, the precipitation of the body-centered cubic lattice Fe phase, which is relatively easy to crystallize, can be promoted, and grains are easily formed.

[0049] The content rate a of Cu is 0.3 atomic % or more and 2.0 atomic % or less, preferably 0.5 atomic % or more and 1.5 atomic % or less, and more preferably 0.7 atomic % or more and 1.3 atomic % or less. It should be noted that when the content rate a of Cu is lower than the lower limit value, the refinement of the grains is impaired, and it may not be possible to form grains with a particle size within the aforementioned range. On the other hand, when the content rate a of Cu is higher than the upper limit value, the mechanical properties of the particles decrease, and they may become brittle.

[0050] When performing heat treatment, Nb (niobium) helps with the refinement of grains together with Cu. Therefore, it is possible to easily form grains with a tiny particle size as described above.

[0051] The content rate b of Nb is 2.0 atomic % or more and 4.0 atomic % or less, preferably 2.5 atomic % or more and 3.5 atomic % or less, and more preferably 2.7 atomic % or more and 3.3 atomic % or less. It should be noted that when the content rate b of Nb is lower than the lower limit value, the refinement of the grains is impaired, and it may not be possible to form grains with a particle size within the aforementioned range. On the other hand, when the content rate b of Nb is higher than the upper limit value, the mechanical properties of the particles decrease, and they may become brittle. In addition, the magnetic permeability of the soft magnetic alloy powder may decrease.

[0052] When manufacturing the soft magnetic alloy powder involved in the implementation method from raw materials, Si (silicon) promotes amorphization. Therefore, when manufacturing the soft magnetic alloy powder involved in the implementation method, a homogeneous amorphous structure is temporarily formed, and then, by making it crystallize, it is easy to form grains with a more uniform particle size. In addition, the uniform particle size contributes to the averaging of the crystalline magnetic anisotropy in each grain, so the coercive force can be reduced and the magnetic permeability can be increased, which helps to improve the soft magnetic properties.

[0053] When manufacturing the soft magnetic alloy powder involved in the implementation method from raw materials, B (boron) promotes amorphization. Therefore, when manufacturing the soft magnetic alloy powder involved in the implementation method, a homogeneous amorphous structure is temporarily formed, and then, by making it crystallize, it is easy to form grains with a more uniform particle size. In addition, the uniform particle size helps to improve the soft magnetic properties. In addition, by using Si and B together, based on the difference in their atomic radii, amorphization can be synergistically promoted.

[0054] Here, when the total content rate of Si and B is set to 1 and the ratio of the content rate of B to this total is set to y, the ratio of the content rate of Si to the total is 1 - y.

[0055] This y is a number that satisfies f(x) ≤ y ≤ 0.99. In addition, f(x) as a function of x is f(x) = (4×10 -34 )x 17.56 .

[0056] Figure 1 is a graph showing regions A to C representing the composition of the soft magnetic alloy powder according to the embodiment in a two-axis orthogonal coordinate system with x as the horizontal axis and y as the vertical axis.

[0057] In Figure 1 , region C is inside the solid line drawn in the orthogonal coordinate system. Specifically, region C is a closed region enclosed by the three straight lines and one curve depicted when the (x, y) coordinates satisfying the four equations x = 72.5, x = 75.5, y = f(x), and y = 0.99 are plotted on the orthogonal coordinate system respectively. However, it does not include the straight line of x = 75.5.

[0058] In addition, y is preferably a number that satisfies f’(x) ≤ y ≤ 0.97. f’(x) is f’(x) = (4×10 -29 )x 14.93 .

[0059] In Figure 1 , region B is inside the dashed line drawn in the orthogonal coordinate system. Specifically, region B is a closed region enclosed by the three straight lines and one curve depicted when the (x, y) coordinates satisfying the four equations x = 72.8, x = 75.0, y = f’(x), and y = 0.97 are plotted in the orthogonal coordinate system respectively.

[0060] Furthermore, y is more preferably a number that satisfies f”(x) ≤ y ≤ 0.95. f”(x) is f”(x) = (4×10 -29 )x 14.93 + 0.05.

[0061] In Figure 1 , region A is inside the dash-dotted line drawn in the orthogonal coordinate system. Specifically, when the (x, y) coordinates satisfying the four equations x = 73.0, x = 74.5, y = f”(x), and y = 0.95 are plotted in the orthogonal coordinate system respectively, region A corresponds to the closed region enclosed by the three straight lines and one curve depicted.

[0062] When manufacturing soft magnetic alloy powder whose composition is included in region C, a homogeneous amorphous structure can be formed with a high probability. Therefore, by crystallizing it, grains with particularly uniform and fine particle sizes can be formed. Thus, soft magnetic alloy powder with sufficiently reduced coercivity and increased permeability can be obtained.

[0063] In addition, even when the Fe content rate is sufficiently increased, the soft magnetic alloy powder whose composition is included in region C can form uniform grains. Thus, soft magnetic alloy powder with sufficiently increased permeability and saturation magnetic flux density can be obtained.

[0064] It should be noted that when the value of y is smaller than region C, the balance between the Si content rate and the B content rate is broken. Therefore, when manufacturing soft magnetic alloy powder, it is difficult to form a homogeneous amorphous structure. As a result, it is impossible to form grains with a small particle size, and the coercivity cannot be sufficiently reduced.

[0065] On the other hand, when the value of y is larger than region C, the balance between the Si content rate and the B content rate is broken. Therefore, when manufacturing soft magnetic alloy powder, it is difficult to form a homogeneous amorphous structure. As a result, it is impossible to form grains with a small particle size, and the coercivity cannot be sufficiently reduced.

[0066] It should be noted that the lower limit value of y is preferably 0.30 or more, more preferably 0.45 or more, and still more preferably 0.55 or more. Thus, further high saturation magnetic flux density and high permeability of the soft magnetic alloy powder can be achieved.

[0067] In addition, especially in region B and region A, by suppressing the Fe content rate, low coercivity can be achieved while suppressing the decrease in the permeability of the soft magnetic alloy powder.

[0068] There is no particular limitation on (100 - x - a - b) which is the total of the Si content rate and the B content rate. It is preferably 15.0 atomic% or more and 24.0 atomic% or less, more preferably 18.0 atomic% or more and 23.5 atomic% or less, and still more preferably 20.0 atomic% or more and 23.0 atomic% or less. By making (100 - x - a - b) within the above range, grains with particularly uniform particle sizes can be formed in the soft magnetic alloy powder.

[0069] It should be noted that y(100 - x - a - b) corresponds to the B content rate in the soft magnetic alloy powder. y(100 - x - a - b) is appropriately set in consideration of the aforementioned coercivity and saturation magnetic flux density, etc., but preferably satisfies 5.0 ≤ y(100 - x - a - b) ≤ 17.0, more preferably satisfies 7.0 ≤ y(100 - x - a - b) ≤ 16.0, and still more preferably satisfies 8.0 ≤ y(100 - x - a - b) ≤ 15.0.

[0070] Thus, soft magnetic alloy powder containing B (boron) at a relatively high concentration can be obtained. Even when the Fe content rate is high, such soft magnetic alloy powder can form a homogeneous amorphous structure during its production. Therefore, through subsequent heat treatment, fine grains with a relatively consistent particle size can be formed, the coercive force can be sufficiently reduced, and high magnetic flux density and high magnetic permeability can be achieved simultaneously.

[0071] When y(100 - x - a - b) is lower than the lower limit value, the B content rate becomes smaller. Therefore, during the production of soft magnetic alloy powder, it may be difficult to amorphize due to the overall composition. As a result, low coercive force may be hindered. On the other hand, when y(100 - x - a - b) is higher than the upper limit value, the B content rate becomes larger and the Si content rate relatively decreases. Therefore, the magnetic permeability of the soft magnetic alloy powder decreases, and the saturation magnetic flux density may decrease.

[0072] The soft magnetic alloy powder according to the embodiment, in addition to being composed of the aforementioned Fe x Cu a Nb b (Si 1-y B y ) 100-x-a-b may also contain impurities. As impurities, all elements other than the above can be listed, but the total impurity content rate is preferably 0.50 atomic% or less. If within this range, the impurities are less likely to hinder the effects of this embodiment, so they are allowed to be contained.

[0073] The content rate of each element of the impurities is preferably 0.05 atomic% or less. If within this range, the impurities are less likely to hinder the effects of this embodiment, so they are allowed to be contained.

[0074] The composition and impurities of the soft magnetic alloy powder according to the embodiment have been described above. The composition and impurities are determined by the following analysis methods.

[0075] As analysis methods, for example, atomic absorption spectrometry for iron and steel specified in JIS G 1257:2000, ICP emission spectrometry for iron and steel specified in JIS G 1258:2007, spark discharge emission spectrometry for iron and steel specified in JIS G 1253:2002, fluorescent X-ray analysis for iron and steel specified in JIS G 1256:1997, gravimetric / titrimetric / spectrophotometric methods specified in JIS G 1211~G 1237, etc. can be listed.

[0076] Specifically, for example, a solid emission spectroscopic analysis apparatus manufactured by SPECTRO company, especially an electric spark discharge emission spectroscopic analysis apparatus, model: SPECTROLAB, type: LAVMB08A, and an ICP apparatus CIROS120 type manufactured by Rigaku Corporation can be cited.

[0077] In addition, especially when determining C (carbon) and S (sulfur), the oxygen flow combustion (high-frequency induction heating furnace combustion)-infrared absorption method specified in JIS G 1211:2011 can also be used. Specifically, a carbon / sulfur analysis apparatus, CS-200, manufactured by LECO company can be cited.

[0078] In addition, especially when determining N (nitrogen) and O (oxygen), the nitrogen quantification method for iron and steel specified in JIS G 1228:1997 and the general rule for the oxygen quantification method of metallic materials specified in JIS Z 2613:2006 can also be used. Specifically, an oxygen / nitrogen analysis apparatus, TC-300 / EF-300, manufactured by LECO company can be cited.

[0079] 1.2. Crystal grains

[0080] The particles of the soft magnetic alloy powder according to the embodiment have crystal grains with a particle size of 1.0 nm or more and 30.0 nm or less.

[0081] The crystal grains are constituted of, for example, Fe-Si crystals. The Fe-Si crystals have the characteristic of high saturation magnetic flux density peculiar to the Fe-Si based composition. In addition, by realizing the refinement and uniformization of the particle size of the crystal grains containing Fe-Si crystals, the number density of the crystal grains becomes high. Therefore, even if refined, the saturation magnetic flux density of the crystal grains is hardly reduced. Therefore, a high saturation magnetic flux density can be achieved in the soft magnetic alloy powder.

[0082] In addition, in the particles, since the refinement of the crystal grains is realized, the magnetocrystalline anisotropy in the crystal grains is easily averaged. Therefore, even if the Fe concentration is high, the increase in the coercive force can be suppressed. Therefore, the particles can be made to have a low coercive force. In addition, when a large amount of such crystal grains are contained, the permeability of the particles becomes high.

[0083] From the above, it can be seen that the saturation magnetic flux density and permeability of the particles can be improved, and at the same time, a low coercive force can be achieved.

[0084] In the particles, the content ratio of the crystal grains is 30% by volume or more, preferably 40% by volume or more and 99% by volume or less, and more preferably 55% by volume or more and 95% by volume or less. When the content ratio of the crystal grains is lower than the lower limit value, the ratio of the crystal grains decreases, so the averaging of the crystalline magnetic anisotropy becomes insufficient, and there is a possibility that the magnetic permeability of the soft magnetic alloy powder decreases or the coercive force increases. In addition, there is also a possibility that the saturation magnetic flux density decreases or the iron loss of the compacted magnetic core increases. On the one hand, the content ratio of the crystal grains can also be higher than the upper limit value, but instead, it can be considered that the content ratio of the grain boundaries described later decreases. Then, a situation where the crystal grains are likely to grow rapidly occurs, and due to some deviation of the heat treatment temperature, etc., the crystal grains are likely to become coarser. As a result, there is a possibility that the magnetic permeability of the soft magnetic alloy powder decreases or the coercive force increases.

[0085] The content ratio of the crystal grains is a volume ratio, but it can be considered to be approximately equal to the area ratio of the crystal grains to the area of the cross-section, so the area ratio can also be regarded as the content ratio. Therefore, the content ratio of the crystal grains is obtained as the ratio of the area occupied by the crystal grains in the observation image to the total area of the aforementioned range.

[0086] The particle size of the crystal grains is obtained by observing the cross-section of the particles with an electron microscope and reading from the observation image in a range of 200 nm square centered at a depth of 5 μm from the surface. It should be noted that in this method, assuming a perfect circle having the same area as the area of the crystal grains, the diameter of this perfect circle, that is, the equivalent circle diameter can be used as the particle size of the crystal grains. An electron microscope such as STEM (scanning transmission electron microscope) is used, for example.

[0087] In addition, by averaging the particle sizes of the read crystal grains, the average particle size is obtained. The average particle size of the crystal grains is preferably 2.0 nm or more and 25.0 nm or less, and more preferably 5.0 nm or more and 20.0 nm or less. Thus, the above effects, that is, the effect that the coercive force becomes lower and the magnetic permeability becomes higher, and the effect that the saturation magnetic flux density becomes higher and the iron loss of the compacted magnetic core becomes lower, become more significant. It should be noted that the average particle size of the crystal grains is calculated from 10 or more particle sizes.

[0088] It should be noted that the particles may also contain crystal grains having particle sizes outside the aforementioned range, that is, crystal grains having a particle size less than 1.0 nm or a particle size exceeding 30.0 nm.

[0089] In addition, the fact that the crystal grains contain Fe—Si crystals can be determined by STEM-EDX (energy-dispersive X-ray spectroscopy) analysis. Specifically, first, an observation image of the cross section of the particles is obtained by STEM. The crystal grains are determined based on the observation image. Next, STEM-EDX analysis is performed, and quantitative analysis of each element is performed by a quantification method based on the analysis results. If the Fe concentration is the highest in terms of the atomic ratio in the crystal grains and the Si concentration becomes high next, it can be said that Fe—Si crystals are contained.

[0090] It should be noted that, for example, JEM-ARM200F manufactured by JEOL Ltd. can be used for STEM. In addition, NSS7 manufactured by Thermo Fisher Scientific Inc. can be used as the EDX analyzer. It should be noted that the acceleration voltage during analysis is 120 kV, and in the quantification method using the EDX spectrum, Cliff-Lorimer (MBTS) that does not consider absorption correction is used.

[0091] 1.3. Various characteristics

[0092] The average particle diameter of the soft magnetic alloy powder is 10.0 μm or more and 45.0 μm or less, preferably 15.0 μm or more and 40.0 μm or less, and more preferably 20.0 μm or more and 30.0 μm or less. By using the soft magnetic alloy powder having such an average particle diameter, the path of eddy current flow can be shortened, and thus a compacted powder magnetic core capable of sufficiently suppressing the eddy current loss generated in the particles can be manufactured.

[0093] In particular, when the average particle diameter of the soft magnetic alloy powder is equal to or greater than the lower limit value, by mixing with a soft magnetic powder having a smaller average particle diameter than the soft magnetic alloy powder according to the embodiment, a high compacted powder molding density can be achieved.

[0094] The average particle diameter of the soft magnetic alloy powder is determined as the particle diameter D50 at which 50% is accumulated from the small diameter side in the volume-based particle size distribution obtained by the laser diffraction method.

[0095] When the average particle diameter of the soft magnetic alloy powder is lower than the lower limit value, the soft magnetic alloy powder becomes too fine, and thus the fillability of the soft magnetic alloy powder may easily decrease. As a result, the molding density of the compacted powder magnetic core, which is an example of the compacted powder body, decreases, and thus the saturation magnetic flux density or permeability of the compacted powder magnetic core may decrease. In addition, crystallization may occur due to heat treatment. On the other hand, when the average particle diameter of the soft magnetic alloy powder is higher than the upper limit value, the particle diameter becomes too large, and thus sufficient amorphization may not be achieved in the amorphous alloy powder that is the precursor of the soft magnetic alloy powder. In addition, the relaxation of stress deformation caused by heat treatment becomes insufficient, and it may be difficult to reduce the coercivity.

[0096] Regarding soft magnetic alloy powder, in the volume-based particle size distribution obtained by the laser diffraction method, when the particle size at 10% cumulative from the small diameter side is defined as D10 and the particle size at 90% cumulative from the small diameter side is defined as D90, (D90 - D10) / D50 is preferably about 1.0 or more and 2.5 or less, more preferably about 1.2 or more and 2.3 or less. (D90 - D10) / D50 is an index indicating the degree of dispersion of the particle size distribution. By making this index within the above range, the fillability of the soft magnetic alloy powder becomes good. Therefore, a compacted powder body with particularly high magnetic properties such as permeability and saturation magnetic flux density can be obtained.

[0097] The coercive force of the soft magnetic alloy powder is preferably 8.0 [A / m] (0.1 [Oe]) or more and 79.6 [A / m] (1.0 [Oe]) or less, more preferably 15.9 [A / m] (0.2 [Oe]) or more and 63.7 [A / m] (0.8 [Oe]) or less, and further preferably 23.9 [A / m] (0.3 [Oe]) or more and 47.8 [A / m] (0.6 [Oe]) or less. By using such a soft magnetic alloy powder with a small coercive force, a compacted powder core with sufficiently suppressed hysteresis loss can be manufactured.

[0098] It should be noted that when the coercive force is lower than the above lower limit value, it is difficult to stably manufacture such a soft magnetic alloy powder with a low coercive force, and if the coercive force is overly pursued, it may affect the permeability. On the other hand, when the coercive force is higher than the above upper limit value, since the hysteresis loss increases, the iron loss of the compacted powder core may become large.

[0099] The coercive force of the soft magnetic alloy powder can be measured, for example, by a vibrating sample magnetometer such as TM-VSM1230-MHHL manufactured by Tamagawa Seiki Co., Ltd.

[0100] When the maximum magnetization of the soft magnetic alloy powder is set as Mm [emu / g] and the true density of the particles is set as ρ [g / cm 3 , the saturation magnetic flux density Bs [T] calculated by 4π / 10000×ρ×Mm = Bs is preferably 1.0 [T] or more, more preferably 1.1 [T] or more. In this way, by using a soft magnetic alloy powder with a high saturation magnetic flux density, a compacted powder core that is difficult to saturate even at a high current can be realized.

[0101] In the measurement of the true density ρ of the soft magnetic alloy powder, an automatic gas displacement type densitometer, AccuPyc1330 manufactured by Micromeritics, was used. In addition, in the measurement of the maximum magnetization Mm of the soft magnetic alloy powder, a vibrating sample type magnetometer, a VSM system (TM-VSM1230-MHHL) manufactured by Tamagawa Seiki Co., Ltd., was used.

[0102] 2. Method for manufacturing soft magnetic alloy powder

[0103] Next, the method for manufacturing the soft magnetic alloy powder according to the manufacturing embodiment will be described.

[0104] Figure 2 It is a process diagram showing the configuration of the method for manufacturing the soft magnetic alloy powder according to the embodiment.

[0105] Figure 2 The method for manufacturing the soft magnetic alloy powder shown has a powder manufacturing process S102 and a heat treatment process S104.

[0106] 2.1. Powder manufacturing process

[0107] In the powder manufacturing process S102, powder before heat treatment (amorphous alloy powder) is manufactured.

[0108] The amorphous alloy powder has a composition formula represented by the atomic ratio Fe x Cu a Nb b (Si 1-y B y ) 100-x-a-b [a, b, x satisfy 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, 72.5 ≤ x < 75.5. In addition, y is a number satisfying f(x) ≤ y ≤ 0.99, and f(x) = (4×10 -34 )x 17.56 .] and is composed of an amorphous alloy with impurities. In addition, the average particle size of the amorphous alloy powder is 10.0 μm or more and 45.0 μm or less.

[0109] Such amorphous alloy powder sometimes has stress deformation during the manufacturing process or the like. Therefore, by performing heat treatment on the amorphous alloy powder described later, the stress deformation is alleviated and the amorphous alloy powder is crystallized.

[0110] The crystallinity in each particle of the amorphous alloy powder is less than 50%, preferably 30% or less. Regarding the crystallinity, an X-ray diffraction spectrum is obtained for the amorphous alloy powder and calculated based on the following formula.

[0111] Crystallinity = {Intensity derived from crystallization / (Intensity derived from crystallization + Intensity derived from amorphous)} × 100

[0112] The amorphous alloy powder can be manufactured by any manufacturing method. For example, it can be manufactured by atomization methods such as water atomization method, gas atomization method, rotating water flow atomization method, and various powdering methods such as reduction method, carbonyl method, and pulverization method.

[0113] The atomization method is a method of manufacturing powder by colliding molten raw materials with a fluid such as a high-speed jet of liquid or gas and then pulverizing and cooling them. In the atomization method, depending on the type of cooling medium or the structure of the device, there are water atomization method, gas atomization method, rotating water flow atomization method, etc. Among them, the amorphous alloy powder is preferably manufactured by the water atomization method or the rotating water flow atomization method, and more preferably by the rotating water flow atomization method.

[0114] It should be noted that the "water atomization method" in this specification refers to a method of manufacturing metal powder by using a liquid such as water or oil as a coolant, spraying it in a state of an inverted conical shape converging at a point, and allowing the molten metal to flow down to the converging point and collide with it.

[0115] In addition, the "rotating water flow atomization method" in this specification is a method of forming a coolant layer on the inner peripheral surface by spraying and rotating the coolant along the inner peripheral surface of the cooling cylinder, and allowing the molten metal obtained by melting the raw material of the amorphous alloy powder to fly and contact the coolant layer. The pulverized molten metal enters the coolant layer and is rapidly cooled and solidified. Thus, amorphous alloy powder can be obtained.

[0116] In the rotating water flow atomization method, by continuously supplying the coolant, a extremely high cooling rate can be stably maintained, so the amorphization of the manufactured amorphous alloy powder can be promoted.

[0117] The amorphous alloy powder can also be subjected to classification treatment as needed. As methods of classification treatment, for example, dry classification such as screening classification, inertial classification, centrifugal classification, and pneumatic classification, and wet classification such as sedimentation classification can be cited.

[0118] 2.2. Heat treatment process

[0119] In the heat treatment process S104, the amorphous alloy powder is heat-treated at a temperature of 500 °C or higher and 600 °C or lower. Thus, the stress deformation of the amorphous alloy powder can be alleviated, and soft magnetic alloy powder with a low coercivity can be obtained. In addition, by crystallizing the amorphous alloy powder, soft magnetic alloy powder containing crystal grains with a crystal grain size of 1.0 nm or more and 30.0 nm or less can be obtained.

[0120] The volume resistivity of the compacted powder made of the soft magnetic alloy powder is 10.0×10 -3 [Ω·cm] or less. Thereby, the deviation of the coercive force of the manufactured soft magnetic alloy powder can be suppressed. As the reason for obtaining such an effect, it can be considered that when the volume resistivity is within the above range, a state is formed in which stress deformation is easily relaxed in the atomic arrangement and the like. That is, it can be considered that when the volume resistivity of the soft magnetic alloy powder is within the above range, even if the temperature or time during heat treatment varies from particle to particle, it is difficult to affect the progress of heat treatment. Therefore, low coercivity can be achieved as a whole for the soft magnetic alloy powder, and fine grains with uniform particle sizes can be formed. In addition, since it is difficult to generate particles that are defective due to insufficient or excessive heat treatment, soft magnetic alloy powder that satisfies the specified coercivity and has stable quality can be manufactured efficiently.

[0121] It should be noted that it can be considered that the volume resistivity of the compacted powder is related to the presence or absence of oxides on the particle surface. Therefore, suppressing the generation of oxides during the manufacturing process of the amorphous alloy powder or subsequent heat treatment is one of the methods for reducing the volume resistivity.

[0122] The volume resistivity of the compacted powder is preferably 9.0×10 -3 [Ω·cm] or less, more preferably 7.0×10 -3 [Ω·cm] or less. On the other hand, from the viewpoint of being able to manufacture efficiently and stably, the lower limit value of the volume resistivity of the compacted powder is preferably 1.0×10 -3 [Ω·cm] or more, more preferably 3.0×10 -3 [Ω·cm] or more.

[0123] The method for measuring the volume resistivity of the compacted powder is as described below.

[0124] First, 7.0 g of the soft magnetic alloy powder is placed as a sample in the sample container of the powder resistivity measurement probe unit. The inner radius of the sample container is 10.0 mm. In addition, the radius of the electrode provided on the sample container is 0.7 mm, the electrode interval is 3.0 mm, and the probe is a four-pin type probe. Then, the sample is gradually pressurized by a hydraulic pump attached to the unit to prepare a cylindrical compacted powder with a mass of 7.0 g. The volume resistivity of the compacted powder is measured by a resistivity meter connected to the unit in a state where a pressure of 63.7 MPa is applied to the compacted powder. It should be noted that the powder resistivity measurement probe unit uses a powder resistance measurement system manufactured by Nitto Seiko Analysis Co., Ltd. In addition, the resistivity meter uses a low resistivity meter GP manufactured by Nitto Seiko Analysis Co., Ltd.

[0125] The heat treatment temperature is above 500°C and below 600°C, preferably above 520°C and below 590°C, more preferably above 540°C and below 580°C. If the heat treatment temperature is within the above range, the amorphous alloy powder can be appropriately crystallized, and at the same time, stress deformation can be sufficiently relieved.

[0126] It should be noted that when the heat treatment temperature is lower than the lower limit value, stress deformation cannot be sufficiently relieved, and the coercive force becomes high. In addition, crystallization becomes insufficient. On the one hand, when the heat treatment temperature is higher than the upper limit value, crystallization proceeds excessively and the grain size becomes large.

[0127] The time for maintaining the above temperature during heat treatment (heat treatment time) is preferably 5 minutes or more and 60 minutes or less, more preferably 7 minutes or more and 45 minutes or less, and further preferably 10 minutes or more and 30 minutes or less. If the heat treatment time is within the above range, the amorphous alloy powder can be appropriately crystallized, and stress deformation can be sufficiently relieved.

[0128] It should be noted that when the heat treatment time is lower than the lower limit value, stress deformation cannot be sufficiently relieved, and the coercive force may become high. On the one hand, when the heat treatment time is higher than the upper limit value, no more effects can be expected, and the energy efficiency of heat treatment may decrease. In addition, crystallization may proceed excessively.

[0129] Heat treatment is performed using a heat treatment furnace, for example. The pressure inside the heat treatment furnace can be atmospheric pressure, negative pressure, or positive pressure. Among them, positive pressure is preferred. By performing heat treatment with a positive pressure inside the heat treatment furnace, the heat conductivity around the amorphous alloy powder can be increased inside the heat treatment furnace. As a result, the amorphous alloy powder can be uniformly heated to every corner, and the overall coercive force of the soft magnetic alloy powder can be further reduced.

[0130] The pressure inside the heat treatment furnace is preferably a positive pressure of 5 Pa or more and 1000 Pa or less, more preferably a positive pressure of 10 Pa or more and 700 Pa or less, and further preferably a positive pressure of 30 Pa or more and 500 Pa or less. If the pressure inside the heat treatment furnace is within the above range, the overall coercive force of the soft magnetic alloy powder can be further reduced. In particular, there is gas in the narrow space between the particles of the amorphous alloy powder, and heat conduction propagates while being affected by the inter-particle distance. Therefore, it can be considered that the heat conductivity between particles is easily affected by pressure.

[0131] It should be noted that when the pressure in the heat treatment furnace is lower than the lower limit value, the temperature and the like of the heat treatment of each particle are likely to deviate, and there may be insufficient or excessive heat treatment in a part. On the other hand, when the pressure in the heat treatment furnace is higher than the upper limit value, no more effects can be expected, and the energy efficiency of the heat treatment may be reduced.

[0132] It should be noted that, for example, a positive pressure of 10 Pa is a pressure 10 Pa higher than the atmospheric pressure. For example, when the atmospheric pressure is 101.3 kPa, it means 101.31 kPa.

[0133] The atmosphere in the heat treatment furnace is not particularly limited and may be an acidic atmosphere, a reducing atmosphere, etc., but an inert atmosphere is preferred, and an inert atmosphere with an oxygen volume concentration of 1500 ppm or less is more preferred, and an inert atmosphere with an oxygen volume concentration of 200 ppm or more and 1000 ppm or less is further preferred, and an inert atmosphere with an oxygen volume concentration of 300 ppm or more and 700 ppm or less is particularly preferred. If the oxygen volume concentration of the inert atmosphere is within the above range, oxidation of the amorphous alloy powder can be more reliably suppressed. Therefore, formation of an oxide film on the surface of the particles can be suppressed, and an increase in the volume resistivity of the aforementioned compacted powder body can be suppressed. In addition, if an oxide film is formed, it may be difficult to relieve stress deformation. Accordingly, if the oxygen volume concentration is within the above range, the coercive force of the amorphous alloy powder can be favorably reduced by heat treatment.

[0134] It should be noted that, as the inert gas constituting the inert atmosphere, for example, nitrogen, argon, etc. can be cited.

[0135] 3. Powder Compression Core and Magnetic Element

[0136] Next, the powder compression core and magnetic element according to the embodiment will be described.

[0137] The magnetic element according to the embodiment can be applied to various magnetic elements having a core, such as a choke coil, an inductance element, a noise filter, a reactor, a transformer, a motor, an actuator, a solenoid valve, a generator, etc. In addition, the powder compression core according to the embodiment can be applied to the core included in these magnetic elements.

[0138] Hereinafter, as an example of the magnetic element, two types of coil components will be described as representatives.

[0139] 3.1. Ring Type

[0140] First, the ring-type coil component as the magnetic element according to the embodiment will be described.

[0141] Figure 3 It is a top view schematically showing the ring-type coil component. Figure 3The shown coil component 10 has an annular compacted powder magnetic core 11 and a wire 12 wound around the compacted powder magnetic core 11.

[0142] The compacted powder magnetic core 11 is obtained by mixing the aforementioned soft magnetic alloy powder and a binder, supplying the resulting mixture to a molding die, and pressing and molding it. That is, the compacted powder magnetic core 11 is a compacted body containing the soft magnetic alloy powder related to the embodiment. Such a compacted powder magnetic core 11 has a low coercive force and low iron loss.

[0143] In addition, the coil component 10 includes such a compacted powder magnetic core 11. Such a coil component 10 has low iron loss and contributes to power saving of electronic devices.

[0144] As constituent materials of the binder used in the production of the compacted powder magnetic core 11, for example, organic materials such as silicone resins, epoxy resins, phenolic resins, polyamide resins, polyimide resins, polyphenylene sulfide resins, etc.; phosphates such as magnesium phosphate, calcium phosphate, zinc phosphate, manganese phosphate, cadmium phosphate, etc.; inorganic materials such as sodium silicate, etc. can be cited.

[0145] As a constituent material of the wire 12, a material with high conductivity can be cited. For example, metal materials containing Cu, Al, Ag, Au, Ni, etc. can be cited. In addition, an insulating film is provided on the surface of the wire 12 as needed.

[0146] It should be noted that the shape of the compacted powder magnetic core 11 is not limited to Figure 3 the shown annular shape. For example, it can be a shape with a part of the ring missing, or a shape with a linear shape in the long side direction.

[0147] In addition, the compacted powder magnetic core 11 may also contain soft magnetic powders or non-magnetic powders other than the soft magnetic alloy powder related to the aforementioned embodiment as needed.

[0148] 3.2 Closed magnetic circuit type

[0149] Next, a closed magnetic circuit type coil component as a magnetic component related to the embodiment will be described.

[0150] Figure 4 is a perspective three-dimensional view schematically showing a closed magnetic circuit type coil component.

[0151] Hereinafter, the closed magnetic circuit type coil component will be described. However, in the following description, the differences from the ring type coil component will be mainly described, and the description of the same matters will be omitted.

[0152] Figure 4The coil component 20 shown has a chip-shaped compacted powder magnetic core 21 and a wire 22 embedded inside the compacted powder magnetic core 21 and formed in a coil shape. That is, the compacted powder magnetic core 21 is a compacted body containing soft magnetic alloy powder related to the embodiment. Such a compacted powder magnetic core 21 has a low coercive force and low iron loss.

[0153] In addition, the coil component 20 includes such a compacted powder magnetic core 21. Such a coil component 20 has low iron loss and contributes to power saving of electronic devices.

[0154] It should be noted that the compacted powder magnetic core 21 may also contain, if necessary, soft magnetic powder or non-magnetic powder other than the soft magnetic alloy powder related to the foregoing embodiment.

[0155] 4. Electronic Devices

[0156] Next, based on Figures 5 to 7 an electronic device including the magnetic element related to the embodiment will be described.

[0157] Figure 5 is a perspective view of a mobile personal computer as an electronic device including the magnetic element related to the embodiment. Figure 5 The personal computer 1100 shown includes a main body portion 1104 having a keyboard 1102 and a display unit 1106 having a display portion 100. The display unit 1106 is rotatably supported by the main body portion 1104 via a hinge structure portion. In such a personal computer 1100, magnetic elements 1000 such as a choke coil or an inductance element for a switching power supply, and a motor are built in, for example.

[0158] Figure 6 is a top view of a smart phone as an electronic device including the magnetic element related to the embodiment. Figure 6 The smart phone 1200 shown includes a plurality of operation buttons 1202, a receiver 1204, and a microphone 1206. In addition, a display portion 100 is disposed between the operation buttons 1202 and the receiver 1204. In such a smart phone 1200, magnetic elements 1000 such as an inductance element, a noise filter, and a motor are built in, for example.

[0159] Figure 7 is a perspective view of a digital camera as an electronic device including the magnetic element related to the embodiment. The digital camera 1300 generates a captured image signal by photoelectrically converting the optical image of a subject using an imaging element such as a CCD (Charge Coupled Device).

[0160] Figure 7The digital camera 1300 shown is equipped with a display unit 100 provided on the back surface of the housing 1302. The display unit 100 functions as a viewfinder for displaying a subject as an electronic image. In addition, a light receiving unit 1304 including an optical lens or a CCD is provided on the front side of the housing 1302, that is, the back side in the figure.

[0161] When the photographer confirms the subject image displayed on the display unit 100 and presses the shutter button 1306, the imaging signal of the CCD at that time is transferred / stored in the memory 1308. In such a digital camera 1300, magnetic elements 1000 such as inductance elements and noise filters are also built in, for example.

[0162] It should be noted that as the electronic devices related to the embodiment, in addition to Figure 5 personal computers, Figure 6 smartphones, Figure 7 digital cameras, for example, mobile phones, tablet terminals, watches, inkjet ejection devices such as inkjet printers, notebook personal computers, televisions, video cameras, video recorders, car navigation devices, pagers, electronic notebooks, electronic dictionaries, calculators, electronic game machines, word processors, workstations, videophones, anti-theft video monitors, electronic binoculars, POS terminals, electronic thermometers, sphygmomanometers, glucometers, electrocardiogram measuring devices, ultrasonic diagnostic devices, medical devices such as electronic endoscopes, fish finders, various measuring devices, vehicles, aircraft, marine measuring instruments for ships, mobile body control devices such as motor vehicle control devices, aircraft control devices, railway vehicle control devices, ship control devices, flight simulators, etc.

[0163] Such electronic devices are equipped with the magnetic elements related to the embodiment. Thereby, the effects of the magnetic elements such as low iron loss can be enjoyed, and power saving of the electronic devices can be achieved.

[0164] 5. Effects of the Embodiment

[0165] As described above, the method for manufacturing the soft magnetic alloy powder related to the embodiment has: a powder manufacturing step S102 for manufacturing a composition formula Fe expressed in atomic ratio x Cu a Nb b (Si 1-y B y ) 100-x-a-b [a, b, x satisfy 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, 72.5 ≤ x < 75.5. In addition, y is a number satisfying f(x) ≤ y ≤ 0.99, and f(x) = (4 × 10 -34 )x 17.56The composition and impurity composition, and an amorphous alloy powder having an average particle diameter of 10.0 μm or more and 45.0 μm or less; and a heat treatment step S104, in which the amorphous alloy powder is heat-treated by heating at a temperature of 500 °C or more and 600 °C or less to crystallize the amorphous alloy powder, to produce a soft magnetic alloy powder containing 30% by volume or more of crystal grains having a crystal grain diameter of 1.0 nm or more and 30.0 nm or less. Further, when a compact having a mass of 7.0 g is produced by pressing the soft magnetic alloy powder under a pressure of 63.7 MPa, the volume resistivity of the compact is 10.0×10 -3 [Ω·cm] or less.

[0166] With such a configuration, it is possible to sufficiently relieve the stress deformation of the amorphous alloy powder and produce a soft magnetic alloy powder with a low coercive force. Further, a soft magnetic alloy powder with a small deviation in coercive force and stable quality can be obtained.

[0167] In the method for producing a soft magnetic alloy powder according to the above embodiment, the heat treatment time is 5 minutes or more and 60 minutes or less.

[0168] With such a configuration, it is possible to appropriately crystallize the amorphous alloy powder and sufficiently relieve the stress deformation.

[0169] In the method for producing a soft magnetic alloy powder according to the above embodiment, the coercive force of the soft magnetic alloy powder is 8.0 [A / m] (0.1 [Oe]) or more and 79.6 [A / m] (1.0 [Oe]) or less.

[0170] With such a configuration, it is possible to obtain a soft magnetic alloy powder capable of producing a compacted powder magnetic core with a particularly low coercive force and sufficiently suppressing magnetic hysteresis loss.

[0171] Further, in the method for producing a soft magnetic alloy powder according to the above embodiment, the heat treatment is performed under a positive pressure of 5 Pa or more and 1000 Pa or less.

[0172] With such a configuration, it is possible to further reduce the coercive force as a whole of the soft magnetic alloy powder. Further, during the heat treatment, gas exists in a narrow space between the particles of the amorphous alloy powder, and heat conduction propagates while being affected by the inter-particle distance. Therefore, it can be considered that the thermal conductivity between the particles is easily affected by the pressure. Therefore, by performing the heat treatment under the above pressure, the temperature deviation during the heat treatment can be suppressed.

[0173] Further, in the method for producing a soft magnetic alloy powder according to the above embodiment, the heat treatment is performed in an inert atmosphere with an oxygen volume concentration of 1500 ppm or less.

[0174] With such a configuration, oxidation of the amorphous alloy powder can be more reliably suppressed. In addition, since formation of an oxide film on the surface of the particles can be suppressed, stress deformation can be inhibited from being difficult to relieve.

[0175] In addition, the soft magnetic alloy powder according to the embodiment has a composition formula Fe expressed in atomic ratios x Cu a Nb b (Si 1-y B y ) 100-x-a-b [where a, b, and x are numbers in atomic %, satisfying 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, 72.5 ≤ x < 75.5. In addition, y is a number satisfying f(x) ≤ y ≤ 0.99, and f(x) = (4 × 10 -34 )x 17.56 .], and an impurity composition, an average particle size of 10.0 μm or more and 45.0 μm or less, containing 30% by volume or more of crystal grains with a crystal grain size of 1.0 nm or more and 30.0 nm or less, when pressing under a pressure of 63.7 MPa to produce a compacted body with a mass of 7.0 g, the volume resistivity of the compacted body is 10.0 × 10 -3 [Ω·cm] or less.

[0176] With such a configuration, soft magnetic alloy powder with a low coercive force and a small deviation in coercive force can be obtained.

[0177] In addition, the coercive force of the soft magnetic alloy powder according to the embodiment is 8.0 [A / m] (0.1 [Oe]) or more and 79.6 [A / m] (1.0 [Oe]) or less.

[0178] With such a configuration, soft magnetic alloy powder capable of manufacturing a compacted powder magnetic core that can sufficiently suppress hysteresis loss can be obtained.

[0179] In addition, the compacted powder magnetic core according to the embodiment contains the soft magnetic alloy powder according to the embodiment.

[0180] With such a configuration, a compacted powder magnetic core with a low coercive force and a low iron loss can be obtained.

[0181] In addition, the magnetic element according to the embodiment includes the compacted powder magnetic core according to the embodiment.

[0182] With such a configuration, for low iron loss, it can contribute to power saving of electronic devices.

[0183] In addition, the electronic device according to the embodiment includes the magnetic element according to the embodiment.

[0184] With such a configuration, it is possible to enjoy the effects of a magnetic component such as low iron loss and achieve power saving of an electronic device.

[0185] As described above, based on the preferred embodiments, the method for manufacturing a soft magnetic alloy powder, the soft magnetic alloy powder, the compacted powder core, the magnetic component, and the electronic device of the present invention have been described. However, the present invention is not limited thereto. For example, the compacted powder core and the magnetic component according to the present invention may be a compacted powder core and a magnetic component in which each part of the above-described embodiment is replaced with any structure having the same function, or may be a compacted powder core and a magnetic component to which any structure is added in the above-described embodiment.

[0186] In addition, in the above-described embodiment, as an example of the use of the soft magnetic alloy powder of the present invention, a compacted powder core has been described. However, the example of use is not limited thereto. For example, it may also be a magnetic device such as a magnetic fluid, a magnetic shielding sheet, or a magnetic head. In addition, the shape of the compacted powder core or the magnetic component is not limited to the shape shown in the drawings and may be any shape.

[0187] In addition, the method for manufacturing the soft magnetic alloy powder of the present invention may also include steps for any purpose added to the above-described embodiment.

[0188] Examples

[0189] Next, specific examples of the present invention will be described.

[0190] 6. Manufacture of Compacted Powder Core

[0191] 6.1. Sample Nos. 1 to 14

[0192] First, the raw materials were melted in a high-frequency induction furnace and pulverized by a rotating water flow atomization method to obtain an amorphous alloy powder.

[0193] Next, the obtained amorphous alloy powder was heat-treated under the conditions shown in Table 1. Thus, a soft magnetic alloy powder was obtained.

[0194] Next, classification was performed using a classifier with a sieve. The alloy composition of the classified soft magnetic alloy powder is shown in Table 1. In addition, the values of x and y calculated from the alloy composition were plotted on the Figure 1 shown curve graph, and when the alloy composition was included in any of regions A to C, its symbol was indicated in Table 1.

[0195] Next, the classified soft magnetic alloy powder was mixed with epoxy resin as a binder and toluene as an organic solvent to obtain a mixture. It should be noted that the addition amount of the epoxy resin was 2 parts by mass with respect to 100 parts by mass of the soft magnetic alloy powder.

[0196] Next, the obtained mixture was stirred and then dried for a short time to obtain a block-shaped dry body. Next, the dry body was passed through a sieve with a mesh size of 400 μm and pulverized to obtain a granulated powder. The obtained granulated powder was dried at 50° C. for 1 hour.

[0197] Next, the obtained granulated powder was filled into a molding die to obtain a compact under the following molding conditions.

[0198] <Molding conditions>

[0199] Forming method: stamping

[0200] Shape of the molded body: Ring

[0201] · Molded body dimensions: outer diameter 14mm, inner diameter 8mm, thickness 3mm

[0202] Molding pressure: 0.5t / cm 2 (49MPa)

[0203] Molding temperature: 70℃

[0204] Next, the molded body was heated in air at 150° C. for 0.50 hours to cure the binder, thereby obtaining a powder magnetic core.

[0205] The average particle size of the soft magnetic alloy powder used in manufacturing the powder core, the content ratio of crystal grains, and the volume resistivity of the powder compact are shown in Table 2. The average particle size was measured using a particle size distribution measuring device using a laser diffraction method, namely Microtrac, HRA9320-X100 manufactured by Nikkiso Co., Ltd.

[0206] 6.2 Sample No. 15~33

[0207] Powder cores were obtained in the same manner as in Samples Nos. 1 to 14 except that soft magnetic alloy powders produced under the production conditions shown in Table 3 and having an average particle size, a grain content ratio, and a volume resistivity of a powder compact having the values ​​shown in Table 4 were used.

[0208] It should be noted that in Tables 1 to 4, in each sample N o Among the soft magnetic alloy powders, the powders whose production method corresponds to the present invention are represented as "Examples", and the powders not corresponding to the present invention are represented as "Comparative Examples".

[0209] [Table 1]

[0210] Table 1

[0211]

[0212] [Table 2]

[0213] Table 2

[0214]

[0215] [Table 3]

[0216] Table 3

[0217]

[0218] [Table 4]

[0219] Table 4

[0220]

[0221] 7. Evaluation of Soft Magnetic Alloy Powder

[0222] 7.1 Coercive Force of Soft Magnetic Alloy Powder

[0223] The coercive force of the soft magnetic alloy powder obtained in each example and each comparative example was measured. The measurement results are shown in Table 2 and Table 4.

[0224] 7.2 Deviation of Coercive Force of Soft Magnetic Alloy Powder

[0225] For the soft magnetic alloy powder obtained in each example and each comparative example, the deviation of the coercive force was evaluated by the following method. The evaluation results are shown in Table 2 and Table 4.

[0226] First, 50 g of soft magnetic alloy powder was prepared and divided into 10 equal parts. Then, the coercive force of each divided part was measured, and the range of the measured values (the difference between the maximum value and the minimum value) was evaluated according to the following evaluation criteria.

[0227] A: The range of the measured values is extremely small

[0228] B: The range of the measured values is slightly large, but there are few practical obstacles

[0229] C: The range of the measured values is large, and there are some practical obstacles

[0230] D: The range of the measured values is extremely large, and there are many practical obstacles

[0231] 7.3 Permeability of Magnetic Components

[0232] Using the compacted powder cores obtained in each example and each comparative example, magnetic components were fabricated based on the following fabrication conditions.

[0233] · Constituent material of the wire: Cu

[0234] · Wire diameter: 0.6 mm

[0235] · Number of turns: 7 turns

[0236] Next, for the manufactured magnetic components, the magnetic permeability was measured based on the following measurement conditions.

[0237] · Measuring device: Impedance Analyzer 4294A manufactured by Keysight Technology Co., Ltd.

[0238] · Measuring frequency: 1 MHz

[0239] Then, the obtained magnetic permeability was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 2 and Table 4.

[0240] A: Magnetic permeability is 24.5 or more

[0241] B: Magnetic permeability is 23.0 or more and less than 24.5

[0242] C: Magnetic permeability is less than 23.0

[0243] 7.4 Iron loss of magnetic components

[0244] Using the compacted magnetic cores obtained in each example and each comparative example, magnetic components were manufactured based on the following manufacturing conditions.

[0245] · Constituent material of wire: Cu

[0246] · Wire diameter: 0.16 mm

[0247] · Number of turns: 18 turns on the primary side, 18 turns on the secondary side

[0248] Next, for the manufactured magnetic components, the iron loss was measured based on the following measurement conditions. The measurement results are shown in Table 2 and Table 4.

[0249] · Measuring device: BH Analyzer SY-8218 manufactured by Iwasaki Electric Co., Ltd.

[0250] · Measuring frequency: 1 MHz

[0251] · Maximum magnetic flux density: 20 mT

[0252] As shown in Table 2 and Table 4, it was confirmed that the soft magnetic alloy powder obtained in each example has a lower coercive force compared to the soft magnetic alloy powder obtained in each comparative example. In addition, the deviation of the coercive force was also suppressed to be smaller.

[0253] In addition, it was also confirmed that the soft magnetic alloy powder obtained in each example has good magnetic permeability and low iron loss.

Claims

1. A method for manufacturing a soft magnetic alloy powder, characterized in that, comprising: Powder manufacturing process for producing amorphous alloy powder having a composition and impurity constitution represented by a compositional formula Fe x Cu a Nb b (Si 1-y B y ) 100-x-a-b wherein a, b, and x in the compositional formula satisfy 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, 72.5 ≤ x < 75.5, and y is a number satisfying f(x) ≤ y ≤ 0.99, where f(x) = (4 × 10 -34 )x 17.56 ; and a heat treatment step of crystallizing the amorphous alloy powder by heating the amorphous alloy powder at a temperature of 500 °C or higher and 600 °C or lower to produce a soft magnetic alloy powder containing 30% by volume or more of crystal grains having a crystal grain size of 1.0 nm or more and 30.0 nm or less, When a compact with a mass of 7.0 g is produced by pressing the soft magnetic alloy powder under a pressure of 63.7 MPa, the volume resistivity of the compact is 10.0×10 -3 Ω·cm or less.

2. The method for producing a soft magnetic alloy powder according to claim 1, wherein, the time of the heat treatment is 5 minutes or more and 60 minutes or less.

3. The method for producing a soft magnetic alloy powder according to claim 1 or 2, wherein, the coercive force of the soft magnetic alloy powder is 8.0 A / m (i.e., 0.1 Oe) or more and 79.6 A / m (i.e., 1.0 Oe) or less.

4. The method for producing a soft magnetic alloy powder according to claim 1 or 2, wherein, the heat treatment is carried out under a positive pressure of 5 Pa or more and 1000 Pa or less.

5. The method for producing a soft magnetic alloy powder according to claim 1 or 2, wherein, the heat treatment is carried out in an inert atmosphere with an oxygen volume concentration of 1500 ppm or less.

6. A soft magnetic alloy powder, characterized in that, The composition represented by the atomic ratio formula Fe x Cu a Nb b (Si 1-y B y ) 100-x-a-b and the impurity composition. In the composition formula, a, b, and x are numbers in atomic %, satisfying 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, 72.5 ≤ x < 75.

5. Additionally, y is a number satisfying f(x) ≤ y ≤ 0.99, where f(x) = (4 × 10 -34 )x 17.56 , the average particle size is 10.0 μm or more and 45.0 μm or less, it contains 30% by volume or more of crystal grains having a crystal grain size of 1.0 nm or more and 30.0 nm or less, When a compact powder with a mass of 7.0 g is produced by pressurization at a pressure of 63.7 MPa, the volume resistivity of the compact powder is 10.0×10 -3 Ω·cm or less.

7. The soft magnetic alloy powder according to claim 6, wherein, the coercive force is 8.0 A / m (i.e., 0.1 Oe) or more and 79.6 A / m (i.e., 1.0 Oe) or less.

8. A compacted powder magnetic core, characterized in that, it contains the soft magnetic alloy powder according to claim 6 or 7.

9. A magnetic component, characterized in that, it includes the compacted powder magnetic core according to claim 8.

10. An electronic device, characterized in that, it includes the magnetic component according to claim 9.

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