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-y (B1-zCrz) y) 100-x-a-b [wherein 0.3 < = a < = 2.0, 2.0 < = b < = 4.0, 75.5 < = x < = 79.5, 0.55 < = y < = 0.91, and 0.015 < = z < = 0.185 are satisfied. A step for producing an amorphous alloy powder having an average particle diameter of 10.0 [mu] m or more and 45.0 [mu] m or less; and a step for producing the soft magnetic alloy powder by heating at a temperature of 420 DEG C to 620 DEG C. The crystal grain size measured by X-ray diffraction is 5.0 nm to 20.0 nm, and the volume resistivity of the compact is 9.0 * 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 cores, magnetic components, and electronic devices. Background Art

[0002] Patent Document 1 discloses soft magnetic powder containing 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 [where 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]. With such a structure, 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 setting the heating temperature during heat treatment to a temperature lower than the crystallization temperature of the amorphous metal particles.

[0004] Prior Art Documents

[0005] Patent Documents

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

[0009] Technical Solution for Solving the Technical Problem

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

[0011] A powder manufacturing process for manufacturing amorphous alloy powder with an average particle size of 10.0 μm or more and 45.0 μm or less, having a composition represented by an atomic ratio formula Fe x Cu a Nb b (Si 1-y (B 1-z Cr z )y) 100-x-a-b [where a, b, x, y, z satisfy

[0012] 0.3 ≤ a ≤ 2.0,

[0013] 2.0 ≤ b ≤ 4.0,

[0014] 75.5 ≤ x ≤ 79.5,

[0015] 0.55 ≤ y ≤ 0.91,

[0016] 0.015 ≤ z ≤ 0.185]; and

[0017] A heat treatment process for crystallizing the amorphous alloy powder by heat-treating the amorphous alloy powder at a temperature of 420°C or more and 620°C or less to manufacture soft magnetic alloy powder,

[0018] wherein the crystal grain size of the soft magnetic alloy powder measured by X-ray diffraction method is 5.0 nm or more and 20.0 nm or less,

[0019] and 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 9.0 × 10 -3 [Ω·cm] or less.

[0020] The soft magnetic alloy powder according to the application example of the present invention,

[0021] has a composition represented by an atomic ratio formula Fe x Cu a Nb b (Si 1-y (B 1-z Cr z )y) 100-x-a-b [where a, b, x, y, z satisfy

[0022] 0.3 ≤ a ≤ 2.0,

[0023] 2.0 ≤ b ≤ 4.0,

[0024] 75.5 ≤ x ≤ 79.5,

[0025] 0.55 ≤ y ≤ 0.91,

[0026] 0.015 ≤ z ≤ 0.185. The composition and impurity constitution,

[0027] The average particle size is 10.0 μm or more and 45.0 μm or less,

[0028] The crystal grain size measured by X-ray diffraction method is 5.0 nm or more and 20.0 nm or less,

[0029] When pressing under a pressure of 63.7 MPa to produce a compacted powder body with a mass of 7.0 g, the volume resistivity of the compacted powder body is 9.0×10 -3 [Ω·cm] or less.

[0030] The compacted powder core according to the application example of the present invention,

[0031] Contains the soft magnetic alloy powder according to the application example of the present invention.

[0032] The magnetic element according to the application example of the present invention,

[0033] Is provided with the compacted powder core according to the application example of the present invention.

[0034] The electronic device according to the application example of the present invention,

[0035] Is provided with the magnetic element according to the application example of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Is a process diagram showing the configuration of the manufacturing method of the soft magnetic alloy powder according to the embodiment.

[0037] Figure 2 Is a schematic top view of an annular coil component.

[0038] Figure 3 Is a schematic perspective three-dimensional view of a closed magnetic circuit type coil component.

[0039] Figure 4 Is a three-dimensional view of a mobile personal computer as an electronic device provided with the magnetic element according to the embodiment.

[0040] Figure 5 Is a top view of a smart phone as an electronic device provided with the magnetic element according to the embodiment.

[0041] Figure 6 Is a three-dimensional view of a digital camera as an electronic device provided with the magnetic element according to the embodiment.

[0042] Description of Reference Numerals

[0043] 10: Coil component; 11: Compressed powder magnetic core; 12: Lead wire; 20: Coil component; 21: Compressed powder magnetic core; 22: Lead wire; 100: Display unit; 1000: Magnetic element; 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; S102: Powder manufacturing process; S104: Heat treatment process. Detailed Description of the Invention

[0044] Hereinafter, based on the preferred embodiments shown in the drawings, the method for manufacturing a soft magnetic alloy powder, the soft magnetic alloy powder, the compressed powder magnetic core, the magnetic element, and the electronic device of the present invention will be described in detail.

[0045] 1. Soft Magnetic Alloy Powder

[0046] First, the soft magnetic alloy powder according to the embodiment will be described.

[0047] The soft magnetic alloy powder can be applied to any use, for example, for manufacturing a compressed powder magnetic core. The compressed powder magnetic core is manufactured by molding while bonding particles of the soft magnetic alloy powder to each other.

[0048] The soft magnetic alloy powder according to the embodiment has a composition represented by an atomic ratio formula Fe x Cu a Nb b (Si 1-y (B 1-z Cr z )y) 100-x-a-b and impurities. a, b, x, y, and z satisfy 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, 75.5 ≤ x ≤ 79.5, 0.55 ≤ y ≤ 0.91, and 0.015 ≤ z ≤ 0.185.

[0049] In addition, the average particle diameter of the soft magnetic alloy powder according to the embodiment is 10.0 μm or more and 45.0 μm or less.

[0050] Furthermore, the crystal grain diameter of the soft magnetic alloy powder according to the embodiment measured by X-ray diffraction is 5.0 nm or more and 20.0 nm or less. This crystal grain is formed by crystallizing an amorphous alloy powder as a precursor under specified conditions during the manufacture of the soft magnetic alloy powder.

[0051] The soft magnetic alloy powder formed by such heat treatment is a powder with a volume resistivity of 9.0×10 -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.

[0052] 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-mentioned 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 configured such that the volume resistivity of the above-mentioned compact is within the above range has, for example, homogeneity in which the deviation of each measured value is suppressed to a small level when divided into a plurality of particle groups and the coercive force is measured separately. In other words, such a soft magnetic alloy powder can be said to stably enjoy the effect of heat treatment in each particle and achieve 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.

[0053] 1.1. Composition

[0054] 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 composition formula Fe x Cu a Nb b (Si 1-y (B 1-z Cr z )y) 100-x-a-b This composition formula represents the ratio of the number of atoms in the composition composed of six elements: Fe, Cu, Nb, Si, B, and Cr.

[0055] Fe (iron) has a great influence on the basic magnetic properties and mechanical properties of the soft magnetic alloy powder according to the embodiment.

[0056] The content rate x of Fe is 75.5 atomic% or more and 79.5 atomic% or less, preferably 76.0 atomic% or more and 78.5 atomic% or less, and more preferably 76.5 atomic% or more and 78.0 atomic% or less. It should be noted that when the content rate 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 rate x of Fe is higher than the above upper limit value, an amorphous structure cannot be stably formed when manufacturing the soft magnetic alloy powder, so the crystal grain size becomes too large, which may lead to an increase in the coercive force.

[0057] When manufacturing the soft magnetic alloy powder involved in the manufacturing embodiment 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 a crystal phase with the aforementioned crystal grain size is easily formed.

[0058] 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, 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 crystal phase may be impaired. On the one hand, when the content rate a of Cu is higher than the upper limit value, the mechanical properties of the soft magnetic alloy powder decrease and it may become brittle.

[0059] When the amorphous alloy powder is subjected to heat treatment, Nb (niobium) helps with the refinement of crystal grains together with Cu. Therefore, crystal grains with the aforementioned crystal grain size are easily formed.

[0060] 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, 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 crystal grains may be impaired. On the one hand, when the content rate b of Nb is higher than the upper limit value, the mechanical properties of the soft magnetic alloy powder decrease and it may become brittle. In addition, the magnetic permeability of the soft magnetic alloy powder may decrease.

[0061] When manufacturing the soft magnetic alloy powder involved in the manufacturing embodiment from raw materials, Si (silicon) promotes amorphization. Therefore, when manufacturing the soft magnetic alloy powder involved in the manufacturing embodiment, a homogeneous amorphous structure is temporarily formed, and then, by crystallizing it, crystal grains with a more uniform crystal grain size are easily formed. The uniform crystal grain size contributes to the averaging of the magnetocrystalline anisotropy in each crystal grain, so the coercive force can be reduced and the magnetic permeability can be increased, contributing to the improvement of soft magnetism.

[0062] When manufacturing the soft magnetic alloy powder involved in the manufacturing embodiment from raw materials, B (boron) promotes amorphization. Therefore, when manufacturing the soft magnetic alloy powder involved in the manufacturing embodiment, a homogeneous amorphous structure is temporarily formed, and then, by crystallizing it, crystal grains with a more uniform crystal grain size are easily formed. As a result, the coercive force can be reduced and the magnetic permeability can be increased, and the improvement of soft magnetism can be achieved. In addition, by using Si and B together, based on the difference in atomic radii between the two, amorphization can be synergistically promoted.

[0063] Cr (chromium) inhibits the coarsening of grains and achieves the homogenization of the crystal grain size. Thereby, the low coercivity of the soft magnetic alloy powder can be achieved. In addition, Cr improves the oxidation resistance of the soft magnetic alloy powder. Thereby, when the soft magnetic alloy powder is compacted, the density reduction of the compact due to oxides can be suppressed. As a result, the magnetic permeability and saturation magnetic flux density measured in the state of the compact can be improved.

[0064] Here, the total content ratio of Si, B, and Cr (Si + B + Cr) is set to 1, and the ratio of the total content ratio of B and Cr (B + Cr) to this total content ratio (Si + B + Cr) is set to y.

[0065] This y satisfies 0.55 ≤ y ≤ 0.91, preferably satisfies 0.60 ≤ y ≤ 0.90, and more preferably satisfies 0.65 ≤ y ≤ 0.80. Thereby, the balance between the amounts of Si, B, and Cr can be achieved. As a result, both the oxidation resistance and magnetic permeability of the soft magnetic alloy powder can be improved evenly.

[0066] It should be noted that when y is lower than the lower limit value, the oxidation resistance decreases, and the crystal grain size is too small, resulting in a decrease in magnetic permeability. On the one hand, when y is higher than the upper limit value, the crystal grain size becomes too large and the coercivity increases.

[0067] In addition, the ratio of the content ratio of Cr to the total content ratio (B + Cr) is z.

[0068] This z satisfies 0.015 ≤ z ≤ 0.185, preferably satisfies 0.030 ≤ z ≤ 0.150, and more preferably satisfies 0.045 ≤ z ≤ 0.120. Thereby, the balance between the amounts of B and Cr can be achieved. As a result, both the oxidation resistance and magnetic permeability of the soft magnetic alloy powder can be improved evenly.

[0069] It should be noted that when z is lower than the lower limit value, the oxidation resistance decreases, and the crystal grain size becomes too small, resulting in a decrease in magnetic permeability. On the one hand, when z is higher than the upper limit value, the crystal grain size becomes too large and the coercivity increases.

[0070] It should be noted that the content ratio of Si is preferably 1.5 atomic % or more and 14.0 atomic % or less, more preferably 3.0 atomic % or more and 10.0 atomic % or less, and further preferably 4.0 atomic % or more and 8.0 atomic % or less. Thereby, the magnetic permeability of the soft magnetic alloy powder can be further improved, and the coercivity can be further reduced.

[0071] In addition, the content of B is preferably 5.0 atomic % or more and 17.0 atomic % or less, more preferably 7.0 atomic % or more and 16.0 atomic % or less, and still more preferably 9.0 atomic % or more and 13.5 atomic % or less. Thereby, the magnetic permeability of the soft magnetic alloy powder can be further increased, and the coercive force can be further decreased.

[0072] In addition, the content of Cr is preferably 0.3 atomic % or more and 2.7 atomic % or less, more preferably 0.5 atomic % or more and 2.2 atomic % or less, and still more preferably 0.8 atomic % or more and 1.8 atomic % or less. Thereby, the oxidation resistance of the soft magnetic alloy powder can be further increased, and the formation of oxides can be suppressed less. As a result, a decrease in the density of the green compact accompanied by oxides can be suppressed, and the magnetic permeability and saturation magnetic flux density of the molded body can be further increased. In addition, the crystal grain size of the crystal grains contained in each particle can be appropriately controlled, and the balance between low coercive force and high magnetic permeability can be further optimized.

[0073] The soft magnetic alloy powder according to the embodiment, in addition to the composition represented by the above compositional formula Fe x Cu a Nb b (Si 1-y (B 1-z Cr z ) y )100-x-a-b, may also contain impurities. As impurities, all elements other than the above can be cited, but the total content of impurities is preferably 0.50 atomic % or less. If within this range, even if impurities are mixed in, it is difficult to impede the above effects, so they are allowed to be contained.

[0074] In addition, the content of each element contained in the impurities is preferably 0.05 atomic % or less respectively. If within this range, the impurities are difficult to impede the above effects, so they are allowed to be contained.

[0075] In addition, in the impurities, particularly the oxygen content is preferably 1500 ppm or less, more preferably 800 ppm or less in terms of mass ratio. If the oxygen content is within the above range, the formation of oxides, which is the cause of the decrease in the density of the green compact, can be suppressed particularly little.

[0076] The soft magnetic alloy powder according to the embodiment has been described above, and the above composition and impurities are determined by the following analysis methods.

[0077] As an analysis method, for example, the atomic absorption spectrometry for iron and steel specified in JIS G 1257:2000, the ICP emission spectrometry for iron and steel specified in JIS G 1258:2007, the spark discharge emission spectrometry for iron and steel specified in JIS G 1253:2002, the fluorescent X-ray spectrometry for iron and steel specified in JIS G 1256:1997, the gravimetric / titrimetric / spectrophotometric methods specified in JIS G 1211 to G 1237, etc. can be cited.

[0078] Specifically, a solid emission spectrometry device is preferably used, such as those manufactured by SPECTRO, SPECTRO LABM9, those manufactured by OBLF, QSN750, etc.

[0079] 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, carbon / sulfur analysis devices manufactured by LECO, CS-200 can be cited.

[0080] 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 rules for oxygen quantification methods of metallic materials specified in JIS Z 2613:2006 can also be used. Specifically, oxygen / nitrogen analysis devices manufactured by LECO, TC-300 / EF-300, oxygen / nitrogen / hydrogen analysis devices manufactured by LECO, ONH836, etc. can be cited.

[0081] 1.2. Crystal Grain Size

[0082] The crystal grain size of the soft magnetic alloy powder according to the embodiment, measured by X-ray diffraction method, is 5.0 nm or more and 20.0 nm or less. If the crystal grain size is within such a range, the crystal grain size of the soft magnetic alloy powder is optimized, so that the magnetic permeability of the soft magnetic alloy powder can be improved. In addition, the crystal magnetic anisotropy of each crystal grain is easily averaged, and a soft magnetic alloy powder with low coercivity can be obtained. Furthermore, by increasing the magnetic permeability, it is difficult to saturate even at high currents, so it is easy to increase the saturation magnetic flux density of the soft magnetic alloy powder.

[0083] It should be noted that the crystal grain size in the soft magnetic alloy powder is preferably 7.0 nm or more and 15.0 nm or less, more preferably 8.0 nm or more and 13.0 nm or less.

[0084] The measurement of the crystal grain size by X-ray diffraction is carried out by obtaining X-ray diffraction patterns for the soft magnetic alloy powder and a standard specimen respectively, estimating the line width of the diffraction lines derived from Fe, and then calculating the crystal grain size by the Scherrer method. The X-ray diffraction pattern obtained for the standard specimen is used to estimate the line width of the diffraction lines derived from the apparatus. Based on this line width, the crystal grain size calculated from the soft magnetic alloy powder can be corrected.

[0085] Each particle constituting the soft magnetic alloy powder according to the embodiment contains crystal grains having the above-described crystal grain size, but may further contain an amorphous structure. By the coexistence of crystal grains and an amorphous structure, the magnetostriction of the soft magnetic alloy powder can be further reduced. As a result, a soft magnetic alloy powder with a particularly high permeability can be obtained. In addition, a soft magnetic alloy powder whose magnetization can be easily controlled can be obtained.

[0086] 1.3. Various characteristics

[0087] The average particle size 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 a soft magnetic alloy powder having such an average particle size, the path of eddy current flow can be shortened, and thus a powder compact magnetic core capable of sufficiently suppressing the eddy current loss generated in the particles can be manufactured.

[0088] In particular, when the average particle size of the soft magnetic alloy powder is at least the lower limit value, by mixing with a soft magnetic alloy powder having a smaller average particle size than the soft magnetic alloy powder according to the embodiment, a high powder compact molding density can be achieved.

[0089] The average particle size of the soft magnetic alloy powder is determined as the particle size D50 at which 50% is accumulated from the small diameter side in the volume-based particle size distribution obtained by the laser diffraction method.

[0090] When the average particle size 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 be likely to decrease. As a result, the molding density of a powder compact magnetic core, which is an example of a powder compact body, decreases, and thus the saturation magnetic flux density or permeability of the powder compact magnetic core may decrease. In addition, crystallization may occur due to heat treatment. On the other hand, when the average particle size of the soft magnetic alloy powder is higher than the upper limit value, the particle size 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 achieve a low coercive force.

[0091] Regarding soft magnetic alloy powder, in the volume-based particle size distribution obtained by the laser diffraction method, when the particle diameter at 10% cumulative from the small diameter side is defined as D10 and the particle diameter 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 spread 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.

[0092] 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.

[0093] It should be noted that when the coercive force is lower than the 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 upper limit value, since the hysteresis loss increases, the iron loss of the compacted powder core may become large.

[0094] The coercive force of the soft magnetic alloy powder can be measured by a vibrating sample type magnetometer such as TM-VSM1230-MHHL manufactured by Tamagawa Seiki Co., Ltd.

[0095] The permeability of the soft magnetic alloy powder in the compacted powder body according to the embodiment is preferably 24.0 or more, more preferably 25.0 or more at a measurement frequency of 1 MHz. Such a soft magnetic alloy powder helps to realize a magnetic element with excellent DC superposition characteristics, high electromagnetic conversion efficiency at high frequencies, and miniaturization. It should be noted that this permeability is together with an epoxy resin added to the soft magnetic alloy powder at a ratio of 2% by mass, and the soft magnetic alloy powder is formed under a molding pressure of 294 MPa (3 t / cm 2)After forming a ring with an outer diameter of 14 mm, an inner diameter of 8 mm, and a thickness of 3 mm by pressing powder, the measurement was performed in a state where a wire with a wire diameter of 0.6 mm was wound around the ring-shaped molded body 7 times. In the measurement of magnetic permeability, for example, an impedance analyzer such as the 4194A manufactured by Agilent Technologies, Inc. was used. In addition, the measurement frequency was set to 1 MHz, and the effective magnetic permeability calculated from the self-inductance of the closed magnetic circuit core coil was set as the measured value.

[0096] The saturation magnetic flux density of the soft magnetic alloy powder according to the embodiment is preferably 1.25 [T] or more, and more preferably 1.30 [T] or more. Thereby, a magnetic element that is difficult to saturate even at a high current can be obtained.

[0097] The saturation magnetic flux density of the soft magnetic alloy powder is measured, for example, by the following method.

[0098] First, the true specific gravity ρ of the soft magnetic alloy powder is measured by a full-automatic gas displacement type densitometer, AccuPyc1330 manufactured by Micromeritics, Inc. Next, the maximum magnetization Mm of the soft magnetic alloy powder is measured by a vibrating sample type magnetometer, VSM system TM-VSM1230-MHHL manufactured by Tamagawa Seiki Co., Ltd. Then, the saturation magnetic flux density Bs is calculated by the following formula.

[0099] Bs = 4π / 10000 × ρ × Mm

[0100] The density of the compact obtained by mixing the soft magnetic alloy powder according to the embodiment with 2% by mass of epoxy resin and pressing and molding the resulting mixture under a pressure of 294 MPa is preferably 4.99 g / cm 3 or more, and more preferably 5.01 g / cm 3 or more and 5.20 g / cm 3 or less. If the density of the compact is within the above range, the occupancy rate of the oxide in the molded body is sufficiently suppressed, and as a result, the occupancy rate of the alloy can be sufficiently ensured. Thereby, the magnetic permeability and saturation magnetic flux density of the magnetic element can be further improved.

[0101] It should be noted that the soft magnetic alloy powder according to the embodiment may also be mixed with other soft magnetic powders or non-soft magnetic powders and used as a mixed powder for various purposes.

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

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

[0104] Figure 1 is a process diagram showing the structure of the method for manufacturing the soft magnetic alloy powder according to the embodiment.

[0105] Figure 1 The manufacturing method of 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, powders before heat treatment (amorphous alloy powders) are manufactured.

[0108] The amorphous alloy powder is composed of a composition represented by an atomic ratio formula Fe x Cu a Nb b (Si 1-y (B 1-z Cr z )y) 100-x-a-b [The composition in which a, b, x, y, z satisfy 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, 75.5 ≤ x ≤ 79.5, 0.55 ≤ y ≤ 0.91, 0.015 ≤ z ≤ 0.185] and powder of an amorphous alloy composed of impurities. In addition, the average particle diameter of the amorphous alloy powder is 10.0 μm or more and 45.0 μm or less.

[0109] Such amorphous alloy powders sometimes have stress deformation during manufacturing processes and the like. Therefore, by performing the heat treatment described below on the amorphous alloy powder, 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 due to crystallization / (Intensity due to crystallization + Intensity due to amorphous)} × 100

[0112] The amorphous alloy powder can be manufactured by any manufacturing method. For example, it can be manufactured by various powdering methods such as atomization methods (e.g., water atomization method, gas atomization method, rotating water flow atomization method), 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 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 towards the converging point and collide with it.

[0115] In addition, the "rotating water flow atomization method" in this specification is a method of spraying and supplying a coolant along the inner peripheral surface of a cooling cylinder to rotate it, thereby forming a coolant layer on the inner peripheral surface, and allowing the molten metal obtained by melting the raw material of the amorphous alloy powder to fly and contact the coolant layer. The micronized 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 that 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 420 °C or higher and 620 °C or lower. Thereby, the stress deformation of the amorphous alloy powder can be alleviated, and soft magnetic alloy powder with a low coercive force can be obtained. In addition, by crystallizing the amorphous alloy powder, soft magnetic alloy powder containing crystal grains with a crystal grain size of 5.0 nm or more and 20.0 nm or less measured by X-ray diffraction method can be obtained.

[0120] The volume resistivity of the compact made of this soft magnetic alloy powder is 9.0×10 -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, the state becomes such that stress deformation is easily alleviated 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 depending on the particles, 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 and uniform-sized crystal grains 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 with a specified coercive force and stable quality can be efficiently manufactured.

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

[0122] The volume resistivity of the compacted powder is preferably 8.0×10 -3 [Ω·cm] or less, more preferably 7.0×10 -3 [Ω·cm] or less. On the one 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 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, through the hydraulic pump attached to the unit, the sample is gradually pressurized to prepare a cylindrical compacted powder with a mass of 7.0 g. In the state where a pressure of 63.7 MPa is applied to the compacted powder, the volume resistivity of the compacted powder is measured by a resistivity meter connected to the unit. It should be noted that the powder resistivity measurement probe unit uses the powder resistance measurement system manufactured by Nitto Seiko Analysis Co., Ltd. In addition, the resistivity meter uses the low resistivity meter GP manufactured by Nitto Seiko Analysis Co., Ltd.

[0125] The temperature of the heat treatment is 420°C or higher and 620°C or lower, preferably 470°C or higher and 610°C or lower, more preferably 500°C or higher and 600°C or lower. If the temperature of the heat treatment is within the above range, the amorphous alloy powder can be appropriately crystallized, and at the same time, the stress deformation can be sufficiently relieved.

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

[0127] The time for maintaining the above temperature during the heat treatment (the 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, 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 the 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 coercivity may become higher. On the one hand, when the heat treatment time is higher than the upper limit value, no additional effects can be expected, and the energy efficiency of the heat treatment may decrease. In addition, crystallization may proceed excessively.

[0129] The heat treatment is carried out 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 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 coercivity of the soft magnetic alloy powder can be further reduced.

[0130] The pressure inside the heat treatment furnace is preferably 5 Pa or more and 1000 Pa or less of positive pressure, more preferably 10 Pa or more and 700 Pa or less of positive pressure, and further preferably 30 Pa or more and 500 Pa or less of positive pressure. If the pressure inside the heat treatment furnace is within the above range, the overall coercivity of the soft magnetic alloy powder can be further reduced. Especially between the particles of the amorphous alloy powder, there is gas in the narrow space, 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 inside the heat treatment furnace is lower than the lower limit value, the temperature and other conditions of the heat treatment of each particle are likely to deviate, and there may be insufficient or excessive heat treatment in some parts. On the one hand, when the pressure inside the heat treatment furnace is higher than the upper limit value, no additional effects can be expected, and the energy efficiency of the heat treatment may decrease.

[0132] It should be noted that, for example, 10 Pa of positive pressure is a pressure 10 Pa higher than 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 preferably an inert atmosphere, more preferably an inert atmosphere with an oxygen volume concentration of 1500 ppm or less, still more preferably an inert atmosphere with an oxygen volume concentration of 200 ppm or more and 1000 ppm or less, and particularly preferably an inert atmosphere with an oxygen volume concentration of 300 ppm or more and 700 ppm or less. 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 above-mentioned compact 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 examples of the inert gas constituting the inert atmosphere include nitrogen, argon, and the like.

[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 of these magnetic elements.

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

[0139] 3.1. Ring Type

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

[0141] Figure 2 is a top view schematically showing the ring-shaped coil component. Figure 2 The shown coil component 10 has an annular powder compression core 11 and a wire 12 wound around the powder compression core 11.

[0142] The powder compression 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 powder compression core 11 is a compact containing the soft magnetic alloy powder according to the embodiment. Such a powder compression 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.; and inorganic materials such as sodium silicate, etc. can be cited.

[0145] As constituent materials of the wire 12, materials 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 2 the annular shape shown. For example, it can be a shape in which a part of the ring is missing, or a shape in which the shape in the long side direction is linear.

[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 powders related to the foregoing embodiments as needed.

[0148] 3.2 Closed magnetic circuit type

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

[0150] Figure 3 is a perspective three-dimensional view schematically showing a coil component of the closed magnetic circuit type.

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

[0152] Figure 3 The 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 the soft magnetic alloy powder related to the embodiment. Such a compacted powder magnetic core 21 has 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, as required, soft magnetic powders or non-magnetic powders other than the soft magnetic alloy powders involved in the foregoing embodiments.

[0155] 4. Electronic device

[0156] Next, based on Figures 4 to 6 an electronic device having the magnetic element involved in the embodiment will be described.

[0157] Figure 4 FIG. is a perspective view of a mobile personal computer as an electronic device having the magnetic element involved in the embodiment. Figure 4 The personal computer 1100 shown includes a main body 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 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, a motor, etc. are built in, for example.

[0158] Figure 5 FIG. is a top view of a smart phone as an electronic device having the magnetic element involved in the embodiment. Figure 5 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, a motor, etc. are built in, for example.

[0159] Figure 6 FIG. is a perspective view of a digital camera as an electronic device having the magnetic element involved in 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 6 The digital camera 1300 shown includes a display portion 100 provided on the back surface of a housing 1302. The display portion 100 functions as a viewfinder for displaying the subject as an electronic image. In addition, a light receiving unit 1304 including an optical lens or a CCD, etc. is provided on the front side of the housing 1302, i.e., the back side in the figure.

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

[0162] It should be noted that, as for the electronic devices involved in the embodiments, in addition to Figure 4 personal computers, Figure 5 smartphones, Figure 6 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 consoles, word processors, workstations, video telephones, 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, 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 involved in the embodiments. Thereby, the effects of the magnetic elements such as low iron loss can be enjoyed, and the power saving of the electronic devices can be achieved.

[0164] 5. Effects achieved by the embodiments

[0165] As described above, the manufacturing method of the soft magnetic alloy powder involved in the embodiments has: a powder manufacturing step S102 for manufacturing an amorphous alloy powder having a composition represented by an atomic ratio composition formula Fe x Cu a Nb b (Si 1-y (B 1-z Cr z )y) 100-x-a-b [where a, b, x, y, z satisfy 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, 75.5 ≤ x ≤ 79.5, 0.55 ≤ y ≤ 0.91, 0.015 ≤ z ≤ 0.185.] and an average particle size of 10.0 μm or more and 45.0 μm or less and an impurity composition; and a heat treatment step S104 for crystallizing the amorphous alloy powder by performing heat treatment on the amorphous alloy powder at a temperature of 420°C or more and 620°C or less to manufacture the soft magnetic alloy powder. In addition, the crystal grain size of the soft magnetic alloy powder measured by X-ray diffraction method is 5.0 nm or more and 20.0 nm or less. In addition, when a compact body 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 body is 9.0×10 -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 manufacture soft magnetic alloy powder with a low coercive force. In addition, soft magnetic alloy powder with less deviation in coercive force and stable quality can be obtained.

[0167] In the method for manufacturing soft magnetic alloy powder according to the above-described 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 manufacturing soft magnetic alloy powder according to the above-described 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 soft magnetic alloy powder capable of manufacturing a compacted powder magnetic core with a particularly low coercive force and sufficiently suppressed hysteresis loss.

[0171] In addition, in the method for manufacturing soft magnetic alloy powder according to the above-described 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, further reduction in coercive force can be achieved as a whole for the soft magnetic alloy powder. In addition, 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] In addition, in the method for manufacturing soft magnetic alloy powder according to the above-described 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, it is possible to suppress the stress deformation from being difficult to relieve.

[0175] In addition, the soft magnetic alloy powder according to the above-described embodiment has a composition formula represented by an atomic ratio of Fe x Cu a Nb b (Si 1-y (B 1-z Cr z )y) 100-x-a-b

[0176] [a, b, x, y, and z satisfy

[0177] 0.3 ≤ a ≤ 2.0,

[0178] 2.0 ≤ b ≤ 4.0,

[0179] 75.5 ≤ x ≤ 79.5,

[0180] 0.55 ≤ y ≤ 0.91,

[0181] 0.015 ≤ z ≤ 0.185

[0182] .] Composition and impurity composition,

[0183] The average particle size is 10.0 μm or more and 45.0 μm or less,

[0184] The crystallite size measured by X-ray diffraction method is 5.0 nm or more and 20.0 nm or less,

[0185] When pressing under a pressure of 63.7 MPa to produce a compacted powder body with a mass of 7.0 g, the volume resistivity of the compacted powder body is 9.0×10 -3 [Ω·cm] or less.

[0186] With such a configuration, a soft magnetic alloy powder with low coercivity and small deviation in coercivity can be obtained.

[0187] In addition, in the soft magnetic alloy powder according to the above embodiment, the content rate of Si is 4.0 atomic % or more and 8.0 atomic % or less, the content rate of B is 9.0 atomic % or more and 13.5 atomic % or less, and the content rate of Cr is 0.5 atomic % or more and 2.2 atomic % or less.

[0188] With such a configuration, the permeability of the soft magnetic alloy powder can be further improved, and the coercivity can be further reduced.

[0189] In addition, the coercivity of the soft magnetic alloy powder according to the above embodiment is 8.0 [A / m] (0.1 [Oe]) or more and 79.6 [A / m] (1.0 [Oe]) or less.

[0190] With such a configuration, a soft magnetic alloy powder capable of manufacturing a compacted powder core that can sufficiently suppress hysteresis loss can be obtained.

[0191] In addition, the compacted powder core according to the above embodiment contains the soft magnetic alloy powder according to the above embodiment.

[0192] With such a configuration, a compacted powder core with low coercivity and low iron loss can be obtained.

[0193] In addition, the magnetic element according to the embodiment includes the compacted powder core according to the embodiment.

[0194] With such a configuration, low iron loss can be achieved, which helps to save power in electronic devices.

[0195] In addition, the electronic device according to the embodiment includes the magnetic element according to the embodiment.

[0196] With such a configuration, the effect of the magnetic element such as low iron loss can be enjoyed, and power saving of the electronic device can be achieved.

[0197] As described above, the method for manufacturing a soft magnetic alloy powder, the soft magnetic alloy powder, the compacted powder core, the magnetic element, and the electronic device of the present invention have been described based on preferred embodiments, but the present invention is not limited thereto. For example, the compacted powder core and the magnetic element according to the present invention may be a compacted powder core and a magnetic element in which each part of the embodiment is replaced with an arbitrary structure having the same function, or may be a compacted powder core and a magnetic element to which an arbitrary structure is added in the embodiment.

[0198] In addition, in the above embodiment, as an example of the use of the soft magnetic alloy powder of the present invention, a compacted powder core has been described, but the example of use is not limited thereto. For example, it may also be magnetic devices such as magnetic fluids, magnetic shielding sheets, and magnetic heads. In addition, the shape of the compacted powder core or the magnetic element is not limited to the shape shown in the figure and may be any shape.

[0199] In addition, arbitrary-purpose processes may be added to the above embodiment in the method for manufacturing the soft magnetic alloy powder of the present invention.

[0200] Examples

[0201] Next, specific examples of the present invention will be described.

[0202] 6. Manufacture of Compacted Powder Core

[0203] 6.1. Samples No. 1 to 15

[0204] First, the raw materials were melted in a high-frequency induction furnace and pulverized by the rotating water flow atomization method to obtain amorphous alloy powder.

[0205] Next, the obtained amorphous alloy powder was heat-treated under the conditions shown in Table 1. Thereby, soft magnetic alloy powder was obtained.

[0206] 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.

[0207] 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. The amount of epoxy resin added was 2 parts by mass based on 100 parts by mass of the soft magnetic alloy powder.

[0208] 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.

[0209] Next, the obtained granulated powder was filled into a molding die to obtain a compact under the following molding conditions.

[0210] <Molding conditions>

[0211] Forming method: stamping

[0212] Shape of the molded body: Ring

[0213] · Molded body dimensions: outer diameter 14mm, inner diameter 8mm, thickness 3mm

[0214] Molding pressure: 0.5t / cm 2 (49MPa)

[0215] Molding temperature: 70℃

[0216] 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.

[0217] The average particle size, crystal particle size, oxygen content and volume resistivity of the soft magnetic alloy powder used in manufacturing the powder core 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.

[0218] 6.2. Sample No. 16 to 30

[0219] A powder core was obtained in the same manner as Samples Nos. 1 to 15 except that the soft magnetic alloy powder produced under the production conditions shown in Table 3 had an average particle size, crystal grain size, oxygen content, and volume resistivity of the powder compact having the values ​​shown in Table 4.

[0220] In Tables 1 to 4, among the soft magnetic alloy powders of each sample No., powders produced by methods corresponding to the present invention are indicated as "Examples", and powders not corresponding to the present invention are indicated as "Comparative Examples".

[0221] [Table 1]

[0222] Table 1

[0223]

[0224] [Table 2]

[0225] Table 2

[0226]

[0227] [Table 3]

[0228] Table 3

[0229]

[0230] [Table 4]

[0231] Table 4

[0232]

[0233] 7. Evaluation of Soft Magnetic Alloy Powder

[0234] 7.1 Coercivity of Soft Magnetic Alloy Powder

[0235] The coercivity 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.

[0236] 7.2 Deviation of Coercivity of Soft Magnetic Alloy Powder

[0237] For the soft magnetic alloy powder obtained in each example and each comparative example, the deviation of the coercivity was evaluated by the following method. The evaluation results are shown in Table 2 and Table 4.

[0238] First, 50 g of soft magnetic alloy powder was prepared and divided into 10 equal parts. Then, the coercivity 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.

[0239] A: The range of the measured values is extremely small

[0240] B: The range of the measured values is slightly large, but there are few practical obstacles

[0241] C: The range of the measured values is large, and there are some practical obstacles

[0242] D: The range of the measured values is extremely large, and there are many practical obstacles

[0243] 7.3 Permeability of Magnetic Elements

[0244] Using the compacted powder cores obtained in each of the examples and comparative examples, magnetic components were fabricated based on the following fabrication conditions.

[0245] · Constituent material of the wire: Cu

[0246] · Wire diameter: 0.6 mm

[0247] · Number of turns: 7 turns

[0248] Next, for the fabricated magnetic components, the permeability was measured based on the following measurement conditions.

[0249] · Measuring device: Impedance Analyzer 4294A, manufactured by Keysight Technology Co., Ltd.

[0250] · Measurement frequency: 1 MHz

[0251] Then, the obtained permeability was evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 2 and 4.

[0252] A: Permeability is 24.0 or more

[0253] B: Permeability is 22.5 or more and less than 24.0

[0254] C: Permeability is less than 22.5

[0255] 7.4 Iron loss of magnetic components

[0256] Using the compacted powder cores obtained in each of the examples and comparative examples, magnetic components were fabricated based on the following fabrication conditions.

[0257] · Constituent material of the wire: Cu

[0258] · Wire diameter: 0.16 mm

[0259] · Number of turns: 18 turns on the primary side and 18 turns on the secondary side

[0260] Next, for the fabricated magnetic components, the iron loss was measured based on the following measurement conditions. The measurement results are shown in Tables 2 and 4.

[0261] · Measuring device: BH Analyzer SY-8218, manufactured by Iwasaki Electric Co., Ltd.

[0262] · Measurement frequency: 1 MHz

[0263] · Maximum magnetic flux density: 20 mT

[0264] As shown in Tables 2 and 4, it was confirmed that the soft magnetic alloy powders obtained in the examples had a lower coercivity than those obtained in the comparative examples. In addition, the deviation of the coercivity was also suppressed to be small.

[0265] In addition, it was also confirmed that the soft magnetic alloy powder obtained in each example had 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 an amorphous alloy powder having a composition represented by an atomic ratio formula Fe x Cu a Nb b (Si 1-y (B 1-z Cr z )y) 100-x-a-b and an impurity composition, and having an average particle diameter of 10.0 μm or more and 45.0 μm or less. In the composition formula, a, b, x, y, and z satisfy 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, 75.5 ≤ x ≤ 79.5, 0.55 ≤ y ≤ 0.91, and 0.015 ≤ z ≤ 0.185; and a heat treatment step of crystallizing the amorphous alloy powder by heating the amorphous alloy powder at a temperature of 420 °C or higher and 620 °C or lower to produce a soft magnetic alloy powder, the soft magnetic alloy powder having a crystal grain size of 5.0 nm or more and 20.0 nm or less as measured by X-ray diffraction, When a green 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 green compact is 9.0×10 -3 Ω·cm or less.

2. The method for producing a soft magnetic alloy powder according to claim 1, wherein, the heat treatment time 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 and impurity composition represented by the compositional formula Fe in terms of atomic ratios x Cu a Nb b (Si 1-y (B 1-z Cr z )y) 100-x-a-b In the compositional formula, a, b, x, y, and z satisfy 0.3 ≤ a ≤ 2.0, 2.0 ≤ b ≤ 4.0, 75.5 ≤ x ≤ 79.5, 0.55 ≤ y ≤ 0.91, and 0.015 ≤ z ≤ 0.185 the average particle size is 10.0 μm or more and 45.0 μm or less, the crystal grain size as measured by X-ray diffraction is 5.0 nm or more and 20.0 nm or less, When a compact body with a mass of 7.0 g is produced by pressurization at a pressure of 63.7 MPa, the volume resistivity of the compact body is 9.0×10 -3 Ω·cm or less.

7. The soft magnetic alloy powder according to claim 6, wherein, the Si content is 4.0 atomic % or more and 8.0 atomic % or less, the B content is 9.0 atomic % or more and 13.5 atomic % or less, the Cr content is 0.5 atomic % or more and 2.2 atomic % or less.

8. 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.

9. A compacted powder magnetic core, characterized in that it contains the soft magnetic alloy powder according to any one of claims 6 to 8.

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

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

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