Method of producing amorphous alloy soft-magnetic powder, amorphous alloy soft-magnetic powder, powder magnetic core, magnetic device and electronic appliance

Abstract

To provide an amorphous alloy soft-magnetic powder low in coercive force, a method of producing an amorphous alloy soft-magnetic powder allowing for efficiently producing such an amorphous alloy soft-magnetic powder, a powder magnetic core and magnetic device containing the amorphous alloy soft-magnetic powder, and an electronic appliance having the magnetic device.SOLUTION: A method of producing an amorphous alloy soft-magnetic powder includes the steps of: producing an amorphous alloy powder consisting of a composition of Fea(Si1-xBx)bCc [where 76.0≤a≤81.0, 16.0≤b≤22.0, 0<c≤3.0, 0.5≤x≤0.9] and impurities and having an average particle size of 3.0 μm or greater and 40.0 μm or smaller; and performing heat treatment of heating the powder at 370°C or higher and 460°C or lower, so as to have volume resistivity of 3.7×10-2 [Ω cm] or smaller when the amorphous alloy soft-magnetic powder is pressurized at pressure of 63.7 MPa to make a green compact having a mass of 7.0 g.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In Patent Document 1, the soft magnetic powder according to the application example of the present invention has a composition formula Fe 100-a-b-c-d-e-f-g Cr a Si b B c C d Al e Ti f Co g [However, a, b, c, d, e, f, and g are numbers representing atomic percentages, and satisfy 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.] It contains amorphous metal particles having such a composition. According to such a configuration, soft magnetic powder having good magnetic properties due to the amorphous alloy and low coercive magnetization can be obtained.

[0003] Also, Patent Document 1 discloses performing heat treatment in the production of soft magnetic powder. By performing heat treatment, various defects and anisotropies (stress-induced anisotropy) introduced when manufacturing soft magnetic powder can be reduced. Thereby, low coercive magnetization can be achieved. Furthermore, Patent Document 1 discloses that the heating temperature in the heat treatment should be lower than the crystallization temperature of the amorphous metal particles.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, from the perspective of further reducing the coercive force, the method for producing soft magnetic powder described in Patent Document 1 still has room for improvement. Therefore, an issue is to improve the production method so that the coercive force can be surely reduced without impairing the production efficiency of the soft magnetic powder.

Means for Solving the Problems

[0006] The method for producing an amorphous alloy soft magnetic powder according to an application example of the present invention includes a composition formula Fe represented by an atomic ratio a (Si 1-x B x ) b C c [However, a, b, c, and x satisfy 76.0 ≦ a ≦ 81.0, 16.0 ≦ b ≦ 22.0, 0 < c ≦ 3.0, and 0.5 ≦ x ≦ 0.9.] a powder production step of producing an amorphous alloy powder composed of the composition and impurities, having an average particle size of 3.0 μm or more and 40.0 μm or less, and a heat treatment step of producing an amorphous alloy soft magnetic powder by performing a heat treatment of heating the amorphous alloy powder at a temperature of 370°C or more and 460°C or less, and has when the amorphous alloy soft magnetic powder is pressurized at a pressure of 63.7 MPa to produce a compacted body having a mass of 7.0 g, the volume resistivity of the compacted body is 3.7×10 -2 [Ω·cm] or less.

[0007] The amorphous alloy soft magnetic powder according to an application example of the present invention has a composition formula Fe represented by an atomic ratio a (Si 1-x B x ) b C c [However, a, b, c, and x satisfy 76.0 ≦ a ≦ 81.0, 16.0 ≦ b ≦ 22.0, 0 < c ≦ 3.0, and 0.5 ≦ x ≦ 0.9.] is composed of the composition and impurities, and The average particle size is 3.0 μm or more and 40.0 μm or less, when a compacted powder with a mass of 7.0 g is produced by being pressurized at a pressure of 63.7 MPa, the volume resistivity of the compacted powder is 3.7×10 -2 [Ω·cm] or less.

[0008] The compacted powder core according to the application example of the present invention contains the amorphous alloy soft magnetic powder according to the application example of the present invention.

[0009] The magnetic element according to the application example of the present invention includes the compacted powder core according to the application example of the present invention.

[0010] The electronic device according to the application example of the present invention includes the magnetic element according to the application example of the present invention.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, the method for manufacturing the amorphous alloy soft magnetic powder, the amorphous alloy soft magnetic powder, the compacted magnetic core, the magnetic element, and the electronic device of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

[0013] 1. Amorphous alloy soft magnetic powder First, the amorphous alloy soft magnetic powder according to the embodiment will be described.

[0014] The amorphous alloy soft magnetic powder can be applied to any use, and for example, it is used in the manufacture of a compacted magnetic core. The compacted magnetic core is manufactured by binding and molding the particles of the amorphous alloy soft magnetic powder.

[0015] The amorphous alloy soft magnetic powder according to the embodiment has a composition formula Fe represented by an atomic ratio a (Si 1-x B x ) b C c [However, a, b, c, and x satisfy 76.0 ≦ a ≦ 81.0, 16.0 ≦ b ≦ 22.0, 0 < c ≦ 3.0, and 0.5 ≦ x ≦ 0.9.] and is composed of impurities.

[0016] Also, the amorphous alloy soft magnetic powder according to the embodiment has an average particle diameter of 3.0 μm or more and 40.0 μm or less.

[0017] Furthermore, when the amorphous alloy soft magnetic powder according to the embodiment is pressurized at a pressure of 63.7 MPa to produce a compacted body having a mass of 7.0 g, the volume resistivity of the compacted body is 3.7 × 10 -2 [Ω·cm] or less.

[0018] According to such a configuration, an amorphous alloy soft magnetic powder with a low coercive force can be obtained. Further, when the volume resistivity of the above-mentioned compacted powder is within the above range, the variation in the coercive force can be suppressed. That is, although the amorphous alloy soft magnetic powder is an aggregate of a large number of particles, when the coercive force is measured by dividing it into a plurality of particle groups, the variation in the measurement results can be suppressed to a small extent. Thereby, for example, when manufacturing a product such as a compacted magnetic core using the amorphous alloy soft magnetic powder, a product with stable characteristics can be manufactured.

[0019] 1.1. Composition Hereinafter, the composition of the amorphous alloy soft magnetic powder will be described in detail. As described above, the amorphous alloy soft magnetic powder according to the embodiment has a composition formula Fe a (Si 1-x B x ) b C c and has a composition represented by this. This composition formula represents the ratio in terms of the number of atoms in the composition consisting of the four elements Fe, Si, B, and C.

[0020] Fe (iron) has a great influence on the basic magnetic properties and mechanical properties of the amorphous alloy soft magnetic powder according to the embodiment.

[0021] The content of Fe is not particularly limited, but in the amorphous alloy soft magnetic powder, Fe is the main component, that is, it is set so that the ratio of the number of atoms is the highest.

[0022] a represents the ratio of Fe in terms of the number of atoms, and 76.0 ≤ a ≤ 81.0, preferably 77.0 ≤ a ≤ 80.7, more preferably 78.0 ≤ a ≤ 80.5. When a is less than the lower limit value, the magnetic properties or corrosion resistance deteriorate. On the other hand, when a exceeds the upper limit value, it becomes easy to crystallize during the production of the amorphous alloy soft magnetic powder. Also, it becomes difficult to lower the coercive force of the amorphous alloy soft magnetic powder.

[0023] When producing amorphous alloy soft magnetic powder from raw materials, Si (silicon) promotes amorphization and increases the magnetic permeability of the amorphous alloy soft magnetic powder. As a result, it is possible to achieve high magnetic permeability and low coercive force.

[0024] When producing amorphous alloy soft magnetic powder from raw materials, B (boron) promotes amorphization. In particular, by using Si and B in combination, synergistic promotion of amorphization can be achieved based on the difference in atomic radii between the two. As a result, high magnetic permeability and low coercive force can be sufficiently achieved.

[0025] x represents the ratio of the number of B atoms to the total number of atoms when the total number of Si atoms and B atoms is set to 1. In the amorphous alloy soft magnetic powder according to this embodiment, 0.5 ≤ x ≤ 0.9, preferably 0.6 ≤ x ≤ 0.8. As a result, the balance between the number of Si atoms and the number of B atoms can be optimized. When x is less than the lower limit value or exceeds the upper limit value, the balance between the number of Si atoms and the number of B atoms is disrupted. For example, when attempting to increase the magnetic properties by increasing the ratio of Fe, amorphization becomes difficult.

[0026] b represents the total ratio of Si and B, and 16.0 ≤ b ≤ 22.0, preferably 17.0 ≤ b ≤ 21.0, more preferably 18.0 ≤ b ≤ 20.0. When b is less than the lower limit value or exceeds the upper limit value, crystallization is likely to occur during the production of the amorphous alloy soft magnetic powder.

[0027] The Si content is preferably 3.0 atomic % or more and 8.0 atomic % or less, more preferably 5.0 atomic % or more and 7.0 atomic % or less.

[0028] The B content is preferably 10.0 atomic % or more and 15.5 atomic % or less, more preferably 12.5 atomic % or more and 14.5 atomic % or less.

[0029] C (carbon) reduces the viscosity of the melt when melting the raw material of the amorphous alloy soft magnetic powder, facilitating amorphization and micronization. As a result, amorphous alloy soft magnetic powder with a small diameter and high magnetic permeability can be obtained. Consequently, eddy current loss can be suppressed even in the high-frequency range.

[0030] c represents the content of C, where 0 < c ≤ 3.0, preferably 1.0 ≤ c ≤ 2.8, and more preferably 1.5 ≤ c ≤ 2.5. When c is below the lower limit value, the viscosity of the melt does not decrease sufficiently, and the shape of the particles becomes irregular. For this reason, the fillability during powder compaction decreases, and the saturation magnetic flux density and magnetic permeability of the compact cannot be increased sufficiently. On the other hand, when c exceeds the upper limit value, crystallization tends to occur during the production of the amorphous alloy soft magnetic powder.

[0031] The amorphous alloy soft magnetic powder according to the embodiment has the above composition formula Fe a (Si 1-x B x ) b C c In addition to the composition represented by, it may contain trace amounts of additive elements. Examples of the trace amounts of additive elements include S (sulfur), P (phosphorus), etc. By including these, the viscosity of the melt can be particularly reduced. As a result, the spheroidization of the particles can be achieved, and the fillability can be increased. Also, these elements are semi-metal elements and contribute to the improvement of the amorphous forming ability. Therefore, the amorphous alloy soft magnetic powder containing these additive elements will have a high degree of amorphization even if the Fe content is high, and can achieve both high magnetic permeability and low coercive force.

[0032] The content rate of S is not particularly limited, but it is preferably 0.0010% by mass or more and 0.0100% by mass or less, more preferably 0.0015% by mass or more and 0.0080% by mass or less, and even more preferably 0.0020% by mass or more and 0.0070% by mass or less. When the content rate of S is lower than the lower limit value, effects such as promotion of spheroidization and improvement of the amorphous formation ability may not be sufficiently obtained. On the other hand, when the content rate of S exceeds the upper limit value, the addition amount may become excessive, and there is a risk of inhibiting the promotion of spheroidization and the improvement of the amorphous formation ability.

[0033] The content rate of P is not particularly limited, but it is preferably 0.0010% by mass or more and 0.0200% by mass or less, more preferably 0.0015% by mass or more and 0.0180% by mass or less, and even more preferably 0.0050% by mass or more and 0.0150% by mass or less. When the content rate of P is lower than the lower limit value, effects such as promotion of spheroidization and improvement of the amorphous formation ability may not be sufficiently obtained. On the other hand, when the content rate of P exceeds the upper limit value, the addition amount may become excessive, and there is a risk of inhibiting the promotion of spheroidization and the improvement of the amorphous formation ability.

[0034] In addition, by adding both S and P, the amorphous formation ability can be particularly enhanced. In this case, the ratio S / P of the content of S to the content of P is preferably 0.2 or more and 0.8 or less, and more preferably 0.3 or more and 0.6 or less. By setting S / P within the above range, it is possible to promote spheroidization and improve the amorphous formation ability while suppressing the respective content rates of S and P. That is, by setting S / P within the above range, an amorphous alloy soft magnetic powder having high magnetic properties during powder pressing and low coercive force can be obtained.

[0035] In addition, the amorphous alloy soft magnetic powder according to the embodiment may contain other elements, regardless of additive elements or impurities, in addition to the elements as described above. The total content of other elements is preferably 1.0 mass% or less, more preferably 0.2 mass% or less, and even more preferably 0.1 mass% or less. Within this range, since the effects of the present invention are less likely to be inhibited by other elements, the inclusion is acceptable.

[0036] As described above, the composition of the amorphous alloy soft magnetic powder according to the embodiment has been described in detail. The above composition and impurities are specified by the following analysis methods.

[0037] Examples of the analysis methods include 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, and absorptiometric methods specified in JIS G 1211 to G 1237, and the like.

[0038] Specifically, for example, a solid emission spectrometry apparatus manufactured by SPECTRO, particularly a spark discharge emission spectrometry apparatus, model: SPECTROLAB, type: LAVMB08A, and an ICP apparatus CIROS120 type manufactured by Rigaku Corporation can be mentioned.

[0039] In particular, when specifying C (carbon) and S (sulfur), the oxygen flow combustion (high-frequency induction heating furnace combustion)-infrared absorption method specified in JIS G 1211:2011 is also used. Specifically, a carbon and sulfur analyzer, CS-200, manufactured by LECO Corporation can be mentioned.

[0040] Furthermore, especially when identifying N (nitrogen) and O (oxygen), the methods for determining nitrogen in iron and steel specified in JIS G 1228:1997 and the general rules for determining oxygen in metallic materials specified in JIS Z 2613:2006 are also used. Specifically, an oxygen / nitrogen analyzer TC-300 / EF-300 manufactured by LECO Corporation can be mentioned.

[0041] Also, if necessary, an insulating film may be formed on the surface of each particle of the obtained amorphous alloy soft magnetic powder. The constituent material of this insulating film is not particularly limited, and examples thereof include inorganic materials such as phosphates such as magnesium phosphate, calcium phosphate, zinc phosphate, manganese phosphate, cadmium phosphate, and silicates such as sodium silicate.

[0042] 1.2. Powder properties The average particle size D50 of the amorphous alloy soft magnetic powder is set to be 3.0 μm or more and 40.0 μm or less, preferably 10.0 μm or more and 35.0 μm or less, and more preferably 20.0 μm or more and 30.0 μm or less. Such amorphous alloy soft magnetic powder is suppressed from crystallizing by heat treatment, and stress strain is sufficiently relaxed. For this reason, low coercive magnetization is easily achieved. Also, because the average particle size is relatively small, it contributes to the realization of a magnetic element with low eddy current loss.

[0043] In particular, when the average particle size D50 is 20.0 μm or more and 40.0 μm or less, an amorphous alloy soft magnetic powder suitable for mixing and using with other soft magnetic powders having a smaller average particle size can be obtained. That is, when the amorphous alloy soft magnetic powder with an average particle size D50 in this range is compression-molded by mixing with other soft magnetic powders with a smaller diameter, it contributes to further densification of the powder core compared to when each is compression-molded alone. Moreover, since the amorphous alloy soft magnetic powder with an average particle size D50 within the above range has a high degree of amorphousness even if it has a large diameter, it contributes to the realization of a magnetic element with high magnetic permeability and low coercive force.

[0044] The average particle diameter D50 of the amorphous alloy soft magnetic powder is determined as the particle diameter at which the cumulative percentage from the smaller diameter side reaches 50% in the volume-based particle size distribution obtained by the laser diffraction method.

[0045] Also, when the average particle diameter of the amorphous alloy soft magnetic powder is less than the lower limit value, the particle diameter becomes too small, so there is a risk that the fillability during powder compacting cannot be sufficiently increased. Also, there is a risk of crystallization by heat treatment. On the other hand, when the average particle diameter of the amorphous alloy soft magnetic powder exceeds the upper limit value, the particle diameter becomes too large, so there is a risk that the degree of amorphization cannot be sufficiently increased. Also, the relaxation of stress strain by heat treatment becomes insufficient, and there is a risk that low coercivity magnetization becomes difficult.

[0046] Also, for the amorphous alloy soft magnetic powder, in the volume-based particle size distribution obtained by the laser diffraction method, when the particle diameter at which the cumulative percentage from the smaller diameter side reaches 10% is defined as D10 and the particle diameter at which the cumulative percentage from the smaller diameter side reaches 90% is defined as D90, (D90 - D10) / D50 is preferably about 1.3 or more and 3.0 or less, and more preferably about 1.8 or more and 2.5 or less. (D90 - D10) / D50 is an index indicating the degree of spread of the particle size distribution, and when this index is within the above range, the fillability of the amorphous alloy soft magnetic powder becomes particularly good. Thereby, an amorphous alloy soft magnetic powder capable of manufacturing a magnetic element having a particularly high magnetic permeability can be obtained.

[0047] 1.3. Magnetic properties The coercivity of the amorphous alloy soft magnetic powder according to the embodiment is preferably 119 [A / m] or less (1.5 [Oe] or less), more preferably 24 [A / m] or more (0.3 [Oe] or more) and 95 [A / m] or less (1.2 [Oe] or less), and even more preferably 40 [A / m] or more (0.5 [Oe] or more) and 80 [A / m] or less (1.0 [Oe] or less).

[0048] By using an amorphous alloy soft magnetic powder having such a particularly low coercivity, a magnetic element capable of sufficiently suppressing hysteresis loss can be manufactured.

[0049] In addition, when the coercive force is lower than the lower limit value, it becomes difficult to stably produce such amorphous alloy soft magnetic powder with low coercive force. Moreover, if the coercive force is pursued too much, it may affect the magnetic permeability. On the other hand, when the coercive force exceeds the upper limit value, since the hysteresis loss increases, there is a possibility that the iron loss of the compacted magnetic core becomes large.

[0050] The coercive force of the amorphous alloy soft magnetic powder can be measured by, for example, a vibrating sample magnetometer such as TM-VSM1230-MHHL manufactured by Tamagawa Seisakusho Co., Ltd.

[0051] The saturation magnetic flux density of the amorphous alloy soft magnetic powder according to the embodiment is preferably 1.60 [T] or more and 2.20 [T] or less, more preferably 1.60 [T] or more and 2.10 [T] or less, and even more preferably 1.65 [T] or more and 2.00 [T] or less.

[0052] By using such amorphous alloy soft magnetic powder with a relatively high saturation magnetic flux density, miniaturization and high output of the magnetic element can be achieved.

[0053] In addition, when the saturation magnetic flux density is lower than the lower limit value, there is a possibility that miniaturization and high output of the magnetic element become difficult. On the other hand, when the saturation magnetic flux density exceeds the upper limit value, it becomes difficult to stably produce such amorphous alloy soft magnetic powder with a high saturation magnetic flux density. Moreover, if the saturation magnetic flux density is pursued too much, it may affect the coercive force and cause an increase in the coercive force.

[0054] The saturation magnetic flux density of the amorphous alloy soft magnetic powder is measured by the following method. First, the true specific gravity ρ of the soft magnetic powder is measured by a fully automatic gas replacement type densitometer, AccuPyc1330 manufactured by Micromeritics. Next, the maximum magnetization Mm of the soft magnetic powder is measured by a vibrating sample magnetometer, a VSM system manufactured by Tamagawa Seisakusho Co., Ltd., TM-VSM1230-MHHL. Then, the saturation magnetic flux density Bs is calculated by the following formula. Bs = 4π / 10000×ρ×Mm

[0055] The magnetic permeability of the amorphous alloy soft magnetic powder according to the embodiment at a measurement frequency of 100 kHz is preferably 18.0 or more, more preferably 20.0 or more. Such amorphous alloy soft magnetic powder contributes to the realization of a compacted powder core having a high saturation magnetic flux density or a small compacted powder core because the magnetic flux density is less likely to saturate even when a high magnetic field is applied. Note that the upper limit value of the magnetic permeability is not particularly limited, but is set to 50.0 or less in consideration of stable production.

[0056] The magnetic permeability of the amorphous alloy soft magnetic powder is the real part of the complex magnetic permeability measured for a toroidal compact formed using the amorphous alloy soft magnetic powder. When producing the compact, an epoxy resin of 2% by mass of the soft magnetic powder is used as a binder.

[0057] 2. Manufacturing method of amorphous alloy soft magnetic powder Next, a method for manufacturing the amorphous alloy soft magnetic powder according to the embodiment will be described.

[0058] FIG. 1 is a process diagram showing the configuration of a method for manufacturing an amorphous alloy soft magnetic powder according to the embodiment.

[0059] The method for manufacturing the amorphous alloy soft magnetic powder shown in FIG. 1 includes a powder manufacturing step S102 and a heat treatment step S104.

[0060] 2.1. Powder manufacturing step In the powder manufacturing step S102, powder (amorphous alloy powder) before heat treatment is manufactured.

[0061] The amorphous alloy powder has a composition formula Fe expressed in terms of atomic ratio a (Si 1-x B x ) b C c[However, a, b, c, and x satisfy 76.0 ≦ a ≦ 81.0, 16.0 ≦ b ≦ 22.0, 0 < c ≦ 3.0, and 0.5 ≦ x ≦ 0.9.] It is a powder composed of an amorphous alloy composed of the composition and impurities. The average particle size of the amorphous alloy powder is 3.0 μm or more and 40.0 μm or less.

[0062] Such amorphous alloy powder may have stress strain during the manufacturing process or the like. Therefore, by subjecting the amorphous alloy powder to the heat treatment described later, the stress strain is relaxed to achieve low coercive magnetization.

[0063] The crystallinity of each particle of the amorphous alloy powder is less than 50%, preferably 30% or less. The crystallinity is calculated based on the following formula after obtaining the X-ray diffraction spectrum of the amorphous alloy powder. Crystallinity = {Intensity derived from crystal / (Intensity derived from crystal + Intensity derived from amorphous)} × 100

[0064] The amorphous alloy powder may be manufactured by any manufacturing method. For example, it is manufactured by various powdering methods such as atomization methods like water atomization method, gas atomization method, rotating water flow atomization method, reduction method, carbonyl method, and pulverization method.

[0065] The atomization method is a method of producing powder by colliding the melted raw material with a fluid such as a liquid or gas jetted at high speed, pulverizing it, and cooling it. Depending on the type of cooling medium and the difference in apparatus configuration, the atomization method includes the water atomization method, gas atomization method, rotating water flow atomization method, etc. Among these, the amorphous alloy powder is preferably manufactured by the water atomization method or the rotating water flow atomization method, and more preferably manufactured by the rotating water flow atomization method.

[0066] In addition, 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 an inverted conical shape that converges at a single point, and flowing and colliding molten metal toward this convergence point.

[0067] On the other hand, the "rotating water flow atomization method" in this specification is a method of forming a coolant layer on the inner peripheral surface by ejecting and supplying a coolant along the inner peripheral surface of a cooling cylinder body and rotating it, and scattering and bringing into contact with the coolant layer a molten metal obtained by melting a raw material of amorphous alloy powder. The pulverized molten metal is taken into the coolant layer and rapidly cooled and solidified. Thereby, amorphous alloy powder is obtained.

[0068] In the rotating water flow atomization method, by continuously supplying the coolant, an extremely high cooling rate can be stably maintained, so that the amorphization of the manufactured amorphous alloy powder is promoted.

[0069] The amorphous alloy powder may be subjected to a classification treatment as necessary. Examples of the classification treatment method include dry classification such as sieving classification, inertial classification, centrifugal classification, and pneumatic classification, and wet classification such as sedimentation classification.

[0070] 2.2. Heat treatment process In the heat treatment process S104, a heat treatment is performed by heating the amorphous alloy powder at a temperature of 370°C or higher and 460°C or lower. Thereby, the stress strain possessed by the amorphous alloy powder can be relaxed, and an amorphous alloy soft magnetic powder having a low coercive force can be obtained.

[0071] In addition, the volume resistivity of the compact formed using the obtained amorphous alloy soft magnetic powder is 3.7×10 -2It is below [[Ω·cm]]. Thereby, the variation in the coercive force of the produced amorphous alloy soft magnetic powder can be suppressed. As a reason for obtaining such an effect, when the volume resistivity is within the above range, it is considered that the stress strain is easily relaxed in the atomic arrangement and the like. That is, when the volume resistivity of the amorphous alloy soft magnetic powder is within the above range, even if the temperature, time, etc. in the heat treatment vary from particle to particle, it is considered that the progress of the heat treatment is hardly affected. For this reason, low coercivity can be achieved for the entire amorphous alloy soft magnetic powder. In addition, since particles that become defective due to insufficient or excessive heat treatment are unlikely to occur, an amorphous alloy soft magnetic powder that satisfies a predetermined coercive force and has stable quality can be efficiently produced.

[0072] Incidentally, the volume resistivity of the compact is considered to be relatively strongly affected by the insulation between particles. Therefore, for example, suppressing the formation of oxides during the production process and heat treatment of amorphous alloy powder is one method of lowering the volume resistivity.

[0073] The volume resistivity of the compact is preferably 3.0×10 -2 [Ω·cm] or less, more preferably 2.5×10 -2 [Ω·cm] or less. On the other hand, from the viewpoint of being able to be efficiently produced, the lower limit value of the volume resistivity of the compact is preferably 0.1×10 -2 [Ω·cm] or more, more preferably 0.5×10 -2 [Ω·cm] or more.

[0074] The method for measuring the volume resistivity of the compact is as follows. First, 7.0 g of amorphous alloy soft magnetic powder is used as a sample and placed in the sample container of the powder resistivity measurement probe unit. The inner radius of the sample container is 10.0 mm. Also, the radius of the electrode provided in the sample container is 0.7 mm, the electrode interval is 3.0 mm, and the probe is a four-probe type. Next, a hydraulic pump attached to the unit is used to gradually pressurize the sample to prepare a compressed powder in the shape of a column with a mass of 7.0 g. With a pressure of 63.7 MPa applied to the compressed powder, the volume resistivity of the compressed powder is measured using a resistivity meter connected to the unit. Note that a powder resistivity measurement system manufactured by Nitto Seiko Analytic Co., Ltd. is used for the powder resistivity measurement probe unit. Also, a low resistivity meter Loresta GP manufactured by Nitto Seiko Analytic Co., Ltd. is used for the resistivity meter.

[0075] The heat treatment temperature is set to be 370°C or higher and 460°C or lower, preferably 380°C or higher and 440°C or lower, and more preferably 390°C or higher and 430°C or lower. If the heat treatment temperature is within the above range, it is possible to sufficiently relieve stress strain while suppressing the crystallization of the amorphous alloy powder.

[0076] Note that if the heat treatment temperature is lower than the lower limit value, the stress strain cannot be sufficiently relieved and the coercive force increases. On the other hand, if the heat treatment temperature exceeds the upper limit value, there is a risk that the amorphous alloy powder will crystallize.

[0077] The time for maintaining the above temperature in the 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 even more preferably 10 minutes or more and 30 minutes or less. If the heat treatment time is within the above range, it is possible to sufficiently relieve stress strain while suppressing the crystallization of the amorphous alloy powder.

[0078] Note that if the heat treatment time is less than the lower limit value, there is a risk that the stress strain cannot be sufficiently relieved and the coercive force may increase. On the other hand, if the heat treatment time exceeds the upper limit value, no further effect can be expected and the energy efficiency of the heat treatment may decrease.

[0079] The heat treatment is performed, for example, using a heat treatment furnace. The pressure inside the heat treatment furnace may be atmospheric pressure, negative pressure, or positive pressure. Among these, a positive pressure is preferable. By performing the heat treatment with a positive pressure inside the heat treatment furnace, the thermal conductivity around the amorphous alloy powder can be increased inside the heat treatment furnace. Thereby, the amorphous alloy powder can be heated evenly to every corner, and further lower magnetic induction magnetization of the entire amorphous alloy soft magnetic powder can be achieved.

[0080] The pressure inside the heat treatment furnace is preferably a positive pressure of 10 Pa or more and 1000 Pa or less, more preferably a positive pressure of 30 Pa or more and 700 Pa or less, and even more preferably a positive pressure of 50 Pa or more and 500 Pa or less. If the pressure inside the heat treatment furnace is within the above range, further lower magnetic induction magnetization of the entire amorphous alloy soft magnetic powder can be achieved. In particular, between the particles of the amorphous alloy powder, gas exists in a narrow space, and it mediates heat conduction while being affected by the inter-particle distance. Therefore, the thermal conductivity between particles is considered to be easily affected by pressure.

[0081] In addition, if the pressure inside the heat treatment furnace is below the lower limit value, the temperature and the like in the heat treatment are likely to vary for each particle, and there is a risk that heat treatment deficiencies or excesses may occur in some parts. On the other hand, if the pressure inside the heat treatment furnace exceeds the upper limit value, no further effects can be expected, and there is a risk that the energy efficiency of the heat treatment will decrease.

[0082] For example, a positive pressure of 10 Pa means a pressure 10 Pa higher than atmospheric pressure. For example, when the atmospheric pressure is 101.3 kPa, it refers to 101.31 kPa.

[0083] The atmosphere inside the heat treatment furnace is not particularly limited and may be, for example, an acidic atmosphere, a reducing atmosphere, etc., but an inert atmosphere is preferred. An inert atmosphere with an oxygen volume concentration of 1500 ppm or less is more preferred, an inert atmosphere with an oxygen volume concentration of 200 ppm or more and 1000 ppm or less is even more 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 above-described compacted powder can be suppressed. Further, when an oxide film is formed, there is a possibility that stress strain is less likely to be relaxed. Based on this, 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.

[0084] Examples of the inert gas constituting the inert atmosphere include nitrogen gas, argon gas, and the like.

[0085] 3. Compacted Powder Core and Magnetic Element Next, the compacted powder core and magnetic element according to the embodiment will be described.

[0086] The magnetic element according to the embodiment is applicable to various magnetic elements provided with a core, such as a choke coil, an inductor, a noise filter, a reactor, a transformer, a motor, an actuator, a solenoid valve, a generator, and the like. Further, the compacted powder core according to the embodiment is applicable to the core provided in these magnetic elements.

[0087] Hereinafter, as an example of the magnetic element, two types of coil components will be described as representatives. 3.1. Toroidal Type First, the toroidal type coil component, which is a magnetic element according to the embodiment, will be described.

[0088] FIG. 2 is a plan view schematically showing a toroidal type coil component. The coil component 10 shown in FIG. 2 includes a ring-shaped compacted powder core 11 and a conductive wire 12 wound around the compacted powder core 11.

[0089] The compacted powder core 11 is obtained by mixing the above-described amorphous alloy soft magnetic powder and a binder, and supplying the resulting mixture to a mold, followed by pressurization and molding. That is, the compacted powder core 11 is a compacted body containing the amorphous alloy soft magnetic powder according to the embodiment. Such a compacted powder core 11 has a low coercive force and low iron loss.

[0090] In addition, the coil component 10 includes such a compacted powder core 11. Such a coil component 10 has low iron loss and contributes to power saving of electronic devices.

[0091] Examples of the constituent materials of the binder used for producing the compacted powder core 11 include 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, and inorganic materials such as silicates such as sodium silicate.

[0092] Examples of the constituent materials of the conductive wire 12 include materials with high conductivity, such as metal materials containing Cu, Al, Ag, Au, Ni, etc. In addition, an insulating film is provided on the surface of the conductive wire 12 as required.

[0093] Note that the shape of the compacted powder core 11 is not limited to the ring shape shown in FIG. 2, and may be, for example, a shape in which a part of the ring is missing, or a shape in which the longitudinal shape is linear.

[0094] Further, the compacted powder core 11 may contain soft magnetic powders or non-magnetic powders other than the amorphous alloy soft magnetic powder according to the above-described embodiment, if necessary. In that case, the ratio of the above-described amorphous alloy soft magnetic powder in the mixed powder of each powder is preferably more than 50% by mass, and more preferably 60% by mass or more.

[0095] 3.2 Closed magnetic circuit type Next, a closed magnetic circuit type coil component, which is a magnetic element according to the embodiment, will be described. FIG. 3 is a perspective view showing schematically a closed magnetic circuit type coil component.

[0096] Hereinafter, the closed magnetic circuit type coil component will be described. In the following description, the description will focus on the differences from the toroidal type coil component, and the description of the same matters will be omitted.

[0097] The coil component 20 shown in FIG. 3 includes a chip-shaped compacted powder core 21 and a conductor 22 embedded inside the compacted powder core 21 and formed in a coil shape. That is, the compacted powder core 21 is a compacted body containing the amorphous alloy soft magnetic powder according to the embodiment. Such a compacted powder core 21 has a low coercive force and a low iron loss.

[0098] Further, the coil component 20 includes such a compacted powder core 21. Such a coil component 20 has a low iron loss and contributes to power saving of electronic devices.

[0099] Note that the compacted powder core 21 may contain soft magnetic powders or non-magnetic powders other than the amorphous alloy soft magnetic powder according to the above-described embodiment, if necessary. In that case, the ratio of the above-described amorphous alloy soft magnetic powder in the mixed powder is preferably more than 50% by mass, and more preferably 60% by mass or more.

[0100] 4. Electronic devices Next, an electronic device including the magnetic element according to the embodiment will be described with reference to FIGS. 4 to 6.

[0101] FIG. 4 is a perspective view showing a mobile personal computer which is an electronic device including the magnetic element according to the embodiment. The personal computer 1100 shown in FIG. 4 includes a main body 1104 having a keyboard 1102 and a display unit 1106 having a display unit 100. The display unit 1106 is rotatably supported with respect to the main body 1104 via a hinge structure unit. Such a personal computer 1100 incorporates a magnetic element 1000 such as a choke coil, an inductor, or a motor for a switching power supply.

[0102] FIG. 5 is a plan view showing a smartphone which is an electronic device including the magnetic element according to the embodiment. The smartphone 1200 shown in FIG. 5 includes a plurality of operation buttons 1202, a receiver 1204, and a transmitter 1206. Further, a display unit 100 is disposed between the operation button 1202 and the receiver 1204. Such a smartphone 1200 incorporates a magnetic element 1000 such as an inductor, a noise filter, or a motor.

[0103] FIG. 6 is a perspective view showing a digital still camera which is an electronic device including the magnetic element according to the embodiment. The digital still camera 1300 photoelectrically converts an optical image of a subject by an imaging element such as a CCD (Charge Coupled Device) to generate an imaging signal.

[0104] The digital still camera 1300 shown in FIG. 6 includes a display unit 100 provided on the back surface of the case 1302. The display unit 100 functions as a finder for displaying a subject as an electronic image. Further, a light receiving unit 1304 including an optical lens, a CCD, etc. is provided on the front side of the case 1302, that is, the back side in the figure.

[0105] When the photographer checks 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 and stored in the memory 1308. Such a digital still camera 1300 also incorporates magnetic elements 1000 such as inductors and noise filters.

[0106] In addition to the personal computer in FIG. 4, the smartphone in FIG. 5, and the digital still camera in FIG. 6, examples of the electronic device according to the embodiment include, for example, mobile phones, tablet terminals, watches, inkjet ejection devices such as inkjet printers, laptop personal computers, televisions, video cameras, video tape recorders, car navigation devices, pagers, electronic notebooks, electronic dictionaries, calculators, electronic game devices, word processors, workstations, videophones, security television monitors, electronic binoculars, POS terminals, electronic thermometers, blood pressure monitors, blood glucose monitors, electrocardiogram measuring devices, ultrasonic diagnostic devices, medical devices such as electronic endoscopes, fish finders, various measuring devices, vehicles, aircraft, ship instruments, mobile control devices such as automotive control devices, aircraft control devices, railway vehicle control devices, and ship control devices, flight simulators, and the like.

[0107] Such an electronic device is provided with the magnetic element according to the embodiment. Thereby, the effect of the magnetic element of low iron loss can be enjoyed, and power saving of the electronic device can be achieved.

[0108] 5. Effects achieved by the embodiment As described above, the method for manufacturing the amorphous alloy soft magnetic powder according to the embodiment includes a powder manufacturing step S102 and a heat treatment step S104. In the powder manufacturing step S102, the composition formula Fe represented by the atomic ratio a (Si 1-x B x ) b C c[However, a, b, c, and x satisfy 76.0 ≦ a ≦ 81.0, 16.0 ≦ b ≦ 22.0, 0 < c ≦ 3.0, and 0.5 ≦ x ≦ 0.9.] An amorphous alloy powder having an average particle size of 3.0 μm or more and 40.0 μm or less, composed of the composition and impurities, is produced. In the heat treatment step S104, an amorphous alloy soft magnetic powder is produced by performing a heat treatment of heating the amorphous alloy powder at a temperature of 370°C or more and 460°C or less. When the produced amorphous alloy soft magnetic powder is pressurized at a pressure of 63.7 MPa to produce a green compact having a mass of 7.0 g, the volume resistivity of the green compact is 3.7×10 -2 [Ω·cm] or less.

[0109] According to such a configuration, the stress strain of the amorphous alloy powder can be sufficiently relaxed, and an amorphous alloy soft magnetic powder having a low coercive force can be efficiently produced. Further, an amorphous alloy soft magnetic powder with little variation in coercive force and stable quality can be obtained.

[0110] The heat treatment time is preferably 5 minutes or more and 60 minutes or less. According to such a configuration, while suppressing the crystallization of the amorphous alloy powder, the stress strain can be sufficiently relaxed.

[0111] The coercive force of the amorphous alloy soft magnetic powder is preferably 119 [A / m] or less (1.5 [Oe] or less).

[0112] According to such a configuration, an amorphous alloy soft magnetic powder capable of manufacturing a magnetic element having a particularly low coercive force and sufficiently suppressing the hysteresis loss can be obtained.

[0113] Further, in the method for producing an amorphous alloy soft magnetic powder according to the above embodiment, it is preferable to perform the heat treatment under a positive pressure of 10 Pa or more and 1000 Pa or less.

[0114] According to such a configuration, further low coercivity magnetization can be achieved for the entire amorphous alloy soft magnetic powder. Also, during the heat treatment, gas exists in the narrow spaces between the particles of the amorphous alloy powder, and it mediates heat conduction while being affected by the inter-particle distance. Therefore, it is considered that the thermal conductivity between the particles is easily affected by pressure. For this reason, by performing the heat treatment under the above pressure, the temperature variation during the heat treatment can be suppressed.

[0115] Moreover, in the method for manufacturing the amorphous alloy soft magnetic powder according to the above embodiment, it is preferable to perform the heat treatment in an inert atmosphere with an oxygen volume concentration of 1500 ppm or less.

[0116] According to such a configuration, oxidation of the amorphous alloy powder can be more reliably suppressed. Also, since the formation of an oxide film on the surface of the particles can be suppressed, it is possible to suppress the difficulty of relaxing stress strain.

[0117] Moreover, the amorphous alloy soft magnetic powder according to the above embodiment has a composition formula Fe represented by the atomic ratio a (Si 1-x B x ) b C c [However, a, b, c, and x satisfy 76.0 ≤ a ≤ 81.0, 16.0 ≤ b ≤ 22.0, 0 < c ≤ 3.0, and 0.5 ≤ x ≤ 0.9.] and is composed of impurities, and the average particle size is 3.0 μm or more and 40.0 μm or less. And when the amorphous alloy soft magnetic powder according to the above embodiment is pressurized at a pressure of 63.7 MPa to produce a green compact with a mass of 7.0 g, the volume resistivity of the green compact is 3.7×10 -2 [Ω·cm] or less. According to such a configuration, an amorphous alloy soft magnetic powder with low coercivity can be obtained.

[0118] Moreover, it is preferable that the amorphous alloy soft magnetic powder according to the above embodiment has a coercivity of 119 [A / m] or less (1.5 [Oe] or less).

[0119] According to such a configuration, an amorphous alloy soft magnetic powder capable of manufacturing a magnetic element capable of sufficiently suppressing hysteresis loss can be obtained.

[0120] Further, the compacted powder core according to the embodiment includes the amorphous alloy soft magnetic powder according to the embodiment. According to such a configuration, a compacted powder core with a low coercive force and low iron loss can be obtained.

[0121] Further, the magnetic element according to the embodiment includes the compacted powder core according to the embodiment. According to such a configuration, it has low iron loss and can contribute to power saving of electronic devices.

[0122] Further, the electronic device according to the embodiment includes the magnetic element according to the embodiment. According to such a configuration, the effect of the magnetic element of low iron loss can be enjoyed, and power saving of the electronic device can be achieved.

[0123] As described above, the method for manufacturing the amorphous alloy soft magnetic powder, the amorphous alloy soft magnetic 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 those in which each part of the above embodiment is replaced with any component having the same function, or those in which any component is added to the above embodiment.

[0124] Further, in the above embodiment, the compacted powder core has been described as an example of the use of the amorphous alloy soft magnetic powder of the present invention, but the examples of use are not limited thereto, and for example, magnetic devices such as magnetic fluids, magnetic shielding sheets, and magnetic heads may be used. Also, the shapes of the compacted powder core and the magnetic element are not limited to those shown, and any shape may be used.

[0125] Further, the method for manufacturing the amorphous alloy soft magnetic powder of the present invention may be one in which a process for any purpose is added to the above embodiment.

Example

[0126] Next, specific examples of the present invention will be described. 6. Manufacturing of powder magnetic cores 6.1. Sample No. 1 First, the raw materials were melted in a high-frequency induction furnace and pulverized by a rotating water jet atomization method to obtain an amorphous alloy powder. Next, the obtained amorphous alloy powder was subjected to a heat treatment under the conditions shown in Table 1.

[0127] Next, classification was performed using a classifier using a mesh. The alloy composition of the amorphous alloy powder after classification is shown in Table 1. The alloy composition was determined using a SPECTRO solid-state optical emission spectrometer, model: SPECTROLAB, type: LAVMB08A.

[0128] Next, the obtained amorphous alloy powder was mixed with an epoxy resin as a binder and toluene as an organic solvent to obtain a mixture. The amount of the epoxy resin added was 2 parts by mass per 100 parts by mass of the amorphous alloy soft magnetic powder.

[0129] Next, the mixture was stirred and then dried for a short time to obtain a lump-shaped dried body. The dried body was then sieved through a sieve with a mesh size of 400 μm, and the dried body was pulverized to obtain a granulated powder. The obtained granulated powder was dried at 50° C. for 1 hour.

[0130] Next, the obtained granulated powder was filled into a molding die, and a molded body was obtained based on the following molding conditions.

[0131] <Molding conditions> Molding method: Press molding Shape of molded body: Ring-shaped -Dimensions of molded body: Outer diameter 14mm, inner diameter 8mm, thickness 3mm Molding pressure: 0.5t / cm 2 (49MPa) ·Molding temperature: 70℃

[0132] Next, the formed body was heated at a temperature of 150°C for 0.50 hours in an air atmosphere to cure the binder. Thereby, a compacted powder core was obtained.

[0133] In addition, Table 2 shows the powder characteristics of the amorphous alloy soft magnetic powder used in the production of the compacted powder core and the volume resistivity of the compacted powder body.

[0134] 6.2. Sample Nos. 2 to 16 A compacted powder core was obtained in the same manner as in the case of Sample No. 1, except that an amorphous alloy soft magnetic powder produced under the production conditions shown in Table 1 and having powder characteristics and a volume resistivity of the compacted powder body as shown in Table 2 was used.

[0135] Note that the heat treatment was omitted for the amorphous alloy soft magnetic powder of Sample No. 8.

[0136] 6.3. Sample Nos. 17 to 25 A compacted powder core was obtained in the same manner as in the case of Sample No. 1, except that an amorphous alloy soft magnetic powder produced under the production conditions shown in Table 3 and having powder characteristics and a volume resistivity of the compacted powder body as shown in Table 4 was used.

[0137] In Tables 1 to 4, among the amorphous alloy soft magnetic powders of each sample No., those corresponding to the present invention in terms of the production method are indicated as "Examples", and those not corresponding to the present invention are indicated as "Comparative Examples".

[0138]

Table 1

[0139]

Table 2

[0140]

Table 3

[0141]

Table 4

[0142] 7. Evaluation of Amorphous Alloy Soft Magnetic Powder 7.1 Powder Characteristics of Amorphous Alloy Soft Magnetic Powder For the amorphous alloy soft magnetic powders obtained in each example and each comparative example, particle size distribution measurement was performed. This measurement was carried out using Microtrac, HRA9320-X100 manufactured by Nikkiso Co., Ltd., which is a particle size distribution measuring device using the laser diffraction method. Then, D10, D50, D90, and (D90 - D10) / D50 were calculated respectively. The calculation results are shown in Table 2 and Table 4.

[0143] 7.2 Coercive Force of Amorphous Alloy Soft Magnetic Powder For the amorphous alloy soft magnetic powders obtained in each example and each comparative example, the coercive force was measured. The measurement results are shown in Table 2 and Table 4.

[0144] 7.3 Variation in Coercive Force of Amorphous Alloy Soft Magnetic Powder For the amorphous alloy soft magnetic powders obtained in each example and each comparative example, the variation in coercive force was evaluated by the following method. The evaluation results are shown in Table 2 and Table 4.

[0145] First, 5 g of amorphous alloy soft magnetic powder was prepared and divided into 10 equal parts. Then, for each of the divided parts, the coercive force 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.

[0146] A: The range of the measured values is particularly small B: The range of the measured values is slightly large, but there is little practical problem C: The range of the measured values is large, and there is a practical problem

[0147] 7.4 Iron Loss of Magnetic Element Using the compacted magnetic cores obtained in each example and each comparative example, magnetic elements were fabricated based on the following fabrication conditions.

[0148] ·Constituent material of the wire: Cu ·Wire diameter of the wire: 0.16 mm ·Number of turns: 18 turns on the primary side and 18 turns on the secondary side

[0149] Next, for the fabricated magnetic element, the iron loss was measured based on the following measurement conditions. The measurement results are shown in Tables 2 and 4.

[0150] ·Measuring device: BH Analyzer SY-8218 manufactured by Iwasaki Telecom Co., Ltd. ·Measurement frequency: 1000 kHz ·Maximum magnetic flux density: 20 mT

[0151] 7.5. Permeability of the magnetic element Using the compacted powder cores obtained in each example and each comparative example, magnetic elements were fabricated based on the following fabrication conditions.

[0152] ·Constituent material of the wire: Cu ·Wire diameter of the wire: 0.6 mm ·Number of turns: 7 turns

[0153] Next, for the fabricated magnetic element, the permeability was measured based on the following measurement conditions. ·Measuring device: Impedance Analyzer 4294A manufactured by Keysight Technologies ·Measurement frequency: 100 kHz

[0154] Then, the obtained permeability was evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 2 and 4.

[0155] A: The permeability is 20.0 or more B: The permeability is 18.0 or more and less than 20.0 C: The permeability is less than 18.0

[0156] As shown in Table 2 and Table 4, it was confirmed that the amorphous alloy soft magnetic powder obtained in each example had a lower coercive force than the amorphous alloy soft magnetic powder obtained in each comparative example. Also, the variation in the coercive force was suppressed to a small extent.

Description of Signs

[0157] 10…Coil component, 11…Compacted powder core, 12…Conducting wire, 20…Coil component, 21…Compacted powder core, 22…Conducting wire, 100…Display unit, 1000…Magnetic element, 1100…Personal computer, 1102…Keyboard, 1104…Main body, 1106…Display unit, 1200…Smartphone, 1202…Operation button, 1204…Receiver, 1206…Microphone, 1300…Digital still camera, 1302…Case, 1304…Light receiving unit, 1306…Shutter button, 1308…Memory, S102…Powder manufacturing process, S104…Heat treatment process

Claims

1. The compositional formula Fe expressed in terms of atomic ratio ａ (Si １－ｘ B ｘ ) ｂ C ｃ [However, a, b, c, and x satisfy 76.0 ≤ a ≤ 81.0, 16.0 ≤ b ≤ 22.0, 0 < c ≤ 3.0, and 0.5 ≤ x ≤ 0.9.] A powder manufacturing process for producing an amorphous alloy powder composed of the composition and impurities thereof, having an average particle size of 3.0 μm or more and 40.0 μm or less, and a heat treatment process for producing an amorphous alloy soft magnetic powder by performing a heat treatment on the amorphous alloy powder at a temperature of 370°C or more and 460°C or less, which has When the amorphous alloy soft magnetic powder is pressed at a pressure of 63.7 MPa to produce a green compact with a mass of 7.0 g, the volume resistivity of the green compact is 3.7×10 －２ [Ω·cm] or less, and a method for producing an amorphous alloy soft magnetic powder is provided.

2. The method for manufacturing an amorphous alloy soft magnetic 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 manufacturing an amorphous alloy soft magnetic powder according to Claim 1 or 2, wherein the coercive force of the amorphous alloy soft magnetic powder is 119 [A / m] or less (1.5 [Oe] or less).

4. The method for manufacturing an amorphous alloy soft magnetic powder according to Claim 1 or 2, wherein the heat treatment is performed under a pressure of 10 Pa or more and 1000 Pa or less of positive pressure.

5. The method for manufacturing an amorphous alloy soft magnetic powder according to Claim 1 or 2, wherein the heat treatment is performed in an inert atmosphere with an oxygen volume concentration of 1500 ppm or less.

6. The compositional formula Fe expressed in terms of atomic ratio ａ (Si １－ｘ B ｘ ) ｂ C ｃ [However, a, b, c, and x satisfy 76.0 ≤ a ≤ 81.0, 16.0 ≤ b ≤ 22.0, 0 < c ≤ 3.0, and 0.5 ≤ x ≤ 0.9.] composed of the composition and impurities thereof, having an average particle size of 3.0 μm or more and 40.0 μm or less, and When a compacted powder with a mass of 7.0 g is produced under a pressure of 63.7 MPa, the volume resistivity of the compacted powder is 3.7×10 －２ [Ω·cm] or less, and it is an amorphous alloy soft magnetic powder characterized by this.

7. The amorphous alloy soft magnetic powder according to Claim 6, having a coercive force of 119 [A / m] or less (1.5 [Oe] or less).

8. A compacted powder core comprising the amorphous alloy soft magnetic powder according to Claim 6 or 7.

9. A magnetic element comprising the compacted powder core according to Claim 8.

10. An electronic device comprising the magnetic element according to Claim 9.

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