JP2020015936A - Powder for magnetic member - Google Patents

Abstract

To provide a powder suitable for a magnetic member capable of reducing loss in a high frequency region.SOLUTION: A powder for magnetic member consists of many particles 2. Material of each particles 2 is an alloy containing Si: 2.0 mass% to 12.0 mass%, Al: 10.0 mass% or less, and the balance: Fe with inevitable impurities. Percentage Pc of the number of particles 2 having circularity of 0.80 or more to total number of the particles 2 is 50% or more. Standard deviation σ when a ratio between a diffraction peak Pα of a (220) surface and a diffraction peak Pβ of a (400) surface (Pα/Pβ) in an X ray diffraction analysis of the particles 2 is measured 10 times is 3 or more and less than 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a powder for a magnetic member. More specifically, the present invention relates to a powder dispersed in a member such as a magnetic sheet and a magnetic ring.

  Portable electronic devices such as mobile phones, notebook personal computers, and tablet personal computers have become widespread in recent years. Recently, miniaturization and high performance of these devices have been advanced. With the downsizing of devices, demands for downsizing and high performance of circuit components in the devices are also increasing. In a miniaturized and high-performance device, the density of electronic components mounted on a circuit is high. Therefore, radio interference between electronic components and radio interference between electronic circuits easily occur due to radio noise radiated from the electronic components. The radio interference causes a malfunction of the electronic device.

  A noise suppression sheet may be inserted into an electronic device for the purpose of suppressing radio wave interference. This noise suppression sheet converts emitted radio waves (noise) into magnetic force to prevent radio waves from being emitted outside the electronic circuit. The processing of the noise suppression sheet is easy, and the degree of freedom of the shape of the sheet is high.

  In a typical conventional noise suppression sheet, an oxide called ferrite is used as a magnetic material. This ferrite has a low magnetic permeability in a high frequency range. Specifically, the magnetic permeability is small in a region where the frequency is from 100 kHz to 20 MHz. Therefore, the conversion efficiency from radio waves to magnetic force in this frequency range is insufficient.

  A magnetic sheet and a magnetic ring that do not include ferrite and include a soft magnetic metal powder having high magnetic permeability have been proposed. JP-A-2017-208416 discloses a noise suppression sheet using an FeMn alloy powder. In this powder, the particles are flattened for the purpose of reducing the demagnetizing coefficient. Japanese Patent Application Laid-Open No. 2001-339193 discloses a noise suppressing sheet using flat Fe-Si-Al powder.

JP-A-2017-208416 JP 2001-339193 A

  Magnetic members used in recent electronic devices have been required to further suppress noise. An object of the present invention is to provide a powder suitable for a magnetic member capable of reducing a loss in a high frequency region.

The magnetic member powder according to the present invention is composed of a large number of particles. The material of each particle is
Si: 2.0% by mass or more and 12.0% by mass or less,
Al: 10.0 mass% or less, and balance: alloy containing Fe and inevitable impurities. The ratio of the number of particles having a circularity of 0.80 or more to the total number of particles is 50% or more.

  Preferably, in the X-ray diffraction analysis of the particles, the standard deviation σ when the ratio (Pα / Pβ) of the diffraction peak Pα on the (220) plane to the diffraction peak Pβ on the (400) plane is measured 10 times is 3 Not less than 20.

According to another aspect, the powder for a magnetic member according to the present invention includes a large number of particles. Each particle has a base particle and an insulating coating covering the base particle. The material of the mother particles is
Si: 2.0% by mass or more and 12.0% by mass or less,
Al: 10.0 mass% or less, and balance: alloy containing Fe and inevitable impurities. The ratio of the number of base particles having a circularity of 0.80 or more to the total number of base particles is 50% or more.

According to yet another aspect, the powder for a magnetic member according to the present invention is obtained by subjecting raw material powder to flattening. This raw material powder is composed of many particles. The material of each particle is
Si: 2.0% by mass or more and 12.0% by mass or less,
Al: 10.0 mass% or less, and balance: alloy containing Fe and inevitable impurities. The ratio of the number of particles having a circularity of 0.80 or more to the total number of particles is 50% or more.

  In the magnetic member using the powder according to the present invention, noise can be suppressed in a frequency range of 100 kHz to 20 MHz.

FIG. 1 is a cross-sectional view illustrating particles of a powder for a magnetic member according to an embodiment of the present invention. FIG. 2 is a sectional view showing a part of a magnetic sheet in which the powder of FIG. 1 is dispersed. FIG. 3 is a cross-sectional view illustrating particles of a powder for a magnetic member according to another embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating particles of a powder for a magnetic member according to another embodiment of the present invention.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings as appropriate.

[First embodiment]
The magnetic member powder according to the present invention is an aggregate of many particles. Each particle has a generally spherical shape. FIG. 1 is a sectional view of the particle 2. FIG. 2 is a sectional view showing a magnetic member (magnetic sheet 4) using this powder. In the magnetic sheet 4, the particles 2 are dispersed in the matrix 6. The material of the matrix 6 is a polymer composition.

  In order to obtain the magnetic sheet 4, a powder is first kneaded with a base polymer such as a resin and a rubber together with various chemicals to obtain a polymer composition. Known methods can be employed for kneading. For example, kneading can be performed by a closed kneader, an open roll, or the like. Examples of the chemical include processing aids such as lubricants and binders.

  Next, a magnetic sheet 4 is formed from this polymer composition. A known method can be adopted for molding. The molding can be performed by a compression molding method, an injection molding method, an extrusion molding method, a rolling method, or the like.

  The shape of the magnetic member is not limited to a sheet. A shape such as a ring shape, a cubic shape, a rectangular parallelepiped shape, and a cylindrical shape may be employed. This powder is also suitable for magnetic members having more complicated shapes.

Indices indicating the performance of the magnetic member include a magnetic permeability μ, a real part magnetic permeability μ ′, and an imaginary part magnetic permeability μ ″. The real part magnetic permeability μ ′ indicates the degree of electromagnetic wave shielding characteristics. "" Indicates the degree of electromagnetic wave absorption characteristics. The magnetic permeability μ can be calculated by the following equation. In this equation, “j” represents an imaginary unit. In other words, the square of "j" is -1.
μ = μ '+ jμ "
In the present application, each of the magnetic permeability μ, the real part magnetic permeability μ ′, and the imaginary part magnetic permeability μ ″ is represented by a relative magnetic permeability, which is a ratio with respect to the vacuum magnetic permeability. It is expressed by the ratio between the imaginary part magnetic permeability μ ″ and the real part magnetic permeability μ ′. In other words, the magnetic loss tan δ is calculated by the following equation.
tanδ = μ ”/ μ '
As is apparent from this equation, the loss tan δ increases when the real part permeability μ ′ decreases and the imaginary part permeability μ ″ increases due to eddy current loss, magnetic resonance, and the like.

  The saturation magnetic flux density of magnetic powder made of metal is higher than that of ferrite. This is an advantage of metal powder. On the other hand, in the conventional metal powder, loss due to magnetic resonance occurs in a low frequency range as compared with ferrite. Therefore, this metal powder is not suitable for loss reduction in a high frequency range (frequency range from 100 kHz to 20 MHz).

  As a result of study, the inventors have found that the X-ray diffraction analysis has a variation in the ratio (Pα / Pβ) between the (220) plane diffraction peak Pα and the (400) plane diffraction peak Pβ in the X-ray diffraction analysis. We have found that large metal powders are suitable for magnetic members. The powder according to the present invention contributes to loss suppression in a high frequency range.

The material of the particles 2 is an alloy. This alloy is
Si: 2.0% by mass or more and 12.0% by mass or less,
Al: 10.0% by mass or less, and balance: Fe and unavoidable impurities.

[Silicon (Si)]
Si increases specific resistance, reduces eddy current loss, and further increases magnetic permeability. In this respect, the content of Si is preferably equal to or greater than 2.0% by mass, and particularly preferably equal to or greater than 3.0% by mass. If the amount of Si is excessive, the saturation magnetic flux density decreases and the magnetic permeability decreases. In light of high magnetic permeability, the Si content is preferably equal to or less than 12.0 mass%, and particularly preferably equal to or greater than 10.0 mass%.

[Aluminum (Al)]
Al increases specific resistance, reduces eddy current loss, and further increases magnetic permeability. In this respect, the Al content is preferably equal to or greater than 1.0% by mass, and particularly preferably equal to or greater than 2.0% by mass. If Al is excessive, the saturation magnetic flux density decreases and the magnetic permeability decreases. In light of high magnetic permeability, the Al content is preferably equal to or less than 10.0% by mass, and particularly preferably equal to or greater than 8.0% by mass.

[Iron (Fe)]
Fe is the base material of the alloy. Fe enhances the magnetic properties of the powder.

[Circularity]
As is clear from FIG. 1, the cross-sectional shape of the particle 2 is substantially circular. In other words, the shape of the particle 2 is substantially a sphere. The powder containing the spherical particles 2 has excellent magnetic properties. In light of the magnetic properties, the circularity of the particles 2 is preferably equal to or greater than 0.80, and particularly preferably equal to or greater than 0.85. The ideal circularity is 1.0. The circularity is an index indicating the complexity of a shape. The circularity C is calculated by the following equation.
C = 4πA / L ²
In this equation, A is the cross-sectional area of the particle, and L is the perimeter of the particle. The circularity C of a perfect circle is 1.0.

  In the powder, the ratio Pc of the number Nc of the particles 2 having the circularity C of 0.80 or more to the total number N of the particles 2 is preferably 50% or more. The powder having the ratio Pc of 50% or more has excellent magnetic properties. In light of the magnetic properties, the ratio Pc is more preferably equal to or greater than 70%, and particularly preferably equal to or greater than 80%. Ideally, the ratio Pc is 100%.

  The area A and the perimeter L can be measured by analyzing a cross-sectional image of the particle 2. A cross-sectional photograph of 1000 or more particles 2 is taken, and the area A and the perimeter L of each particle 2 are measured by a commercially available image analyzer. The measurement can be performed with a device of Seisin Corporation (trade name “PITA-4”). In the measurement by this apparatus, the particles 2 are poured into the cell together with the carrier liquid. An image of the particles 2 is taken by a CCD camera. In each particle 2, the area A and the perimeter L are measured, and the ratio Pc is calculated.

[X-ray diffraction analysis]
This alloy has an ordered phase having a D03 type crystal lattice. When this alloy is analyzed by X-ray diffraction, a diffraction peak Pα on the (220) plane and a diffraction peak Pβ on the (400) plane are detected. The inventor of the present invention has developed as a result that powder having a standard deviation σ of 3 or more and less than 20 when the ratio (Pα / Pβ) of both peaks is measured 10 times has good magnetic properties. Was found. Preferably, the standard deviation σ is 10 or more and less than 20. A typical example of the X-ray diffractometer is Rigaku Corporation's fully automatic multipurpose X-ray diffractometer (trade name "SmartLab SE").

  By devising the heat treatment of the powder, the standard deviation σ can be adjusted. For example, the standard deviation σ can be adjusted by adjusting the cooling rate after heating. The standard deviation σ may be adjusted by repeating the heat treatment a plurality of times. Two or more heat treatments may be applied to the powder to adjust the standard deviation σ.

By devising the method of forming the powder, the standard deviation σ can be adjusted. For example, the standard deviation σ can be adjusted by forming the powder by a method of cooling the molten metal at a cooling rate of 1 × 10 ⁴ ° C./sec or more. As a specific forming method, there is an atomizing method which will be described in detail later.

[Average particle size]
The average particle size D50 of this powder is preferably 20 μm or more and 150 μm or less. A powder having an average particle size D50 of 20 μm or more has excellent fluidity, and thus can be easily mixed with the matrix 6. In this respect, the average particle diameter D50 is more preferably equal to or greater than 25 μm, and particularly preferably equal to or greater than 30 μm. A magnetic sheet 4 having a small thickness can be obtained from a powder having an average particle diameter D50 of 150 μm or less. The magnetic sheet 4 can be applied to a small electronic device. In this respect, the average particle diameter D50 is more preferably equal to or less than 120 μm, and particularly preferably equal to or less than 100 μm.

  The average particle size D50 is a particle diameter at a point where the cumulative curve becomes 50% when the cumulative curve is obtained with the total volume of the powder being 100%. The average particle size D50 is measured by a laser diffraction / scattering type particle size distribution measuring device “Microtrack MT3000” manufactured by Nikkiso Co., Ltd. Powder is poured into the cell of this device together with pure water, and the average particle size is detected based on the light scattering information of the particles 2.

[Production method]
Atomization is suitable for producing a powder containing particles 2 having a high circularity. Typical atomizing methods are a gas atomizing method and a disk atomizing method. The powder may be obtained by a pulse pressure applied orifice injection method.

  In the gas atomization method, a raw material metal is heated and melted to obtain a molten metal. This molten metal flows out of the nozzle. A gas (argon gas, nitrogen gas, or the like) is blown onto the molten metal. Due to the energy of this gas, the molten metal is powdered into droplets, which are cooled while falling. The droplets solidify to form particles 2. In this gas atomizing method, the molten metal is instantaneously formed into droplets and simultaneously cooled, so that a uniform fine structure can be obtained. In addition, since the droplets are continuously formed, the composition difference between the particles 2 is extremely small.

  In the disk atomizing method, a raw material metal is heated and melted to obtain a molten metal. This molten metal flows out of the nozzle. The molten metal is dropped on a high-speed rotating disk. The molten metal is rapidly cooled and solidified to obtain a powder.

  In the pulse pressure application orifice injection method, a raw metal is heated and melted to obtain a molten metal. Droplets are formed from the molten metal while pulse pressure is applied by an actuator toward the orifice hole. The droplet is cooled while falling. The droplets solidify to form particles 2.

[Second embodiment]
FIG. 3 is a sectional view showing particles 8 of a powder for a magnetic member according to another embodiment of the present invention. The particles 8 have a main part 10 and an insulating film 12. The material, properties, size, etc. of the main part 10 are the same as those of the particles 8 shown in FIG.

The method for producing the magnetic member powder is as follows.
(1) a step of obtaining a raw material powder composed of a large number of particles,
And (2) a step of covering the surface of the particles with an insulating film. As the raw material powder, the magnetic member powder according to the first embodiment (see FIG. 1) can be used. Therefore, the material of this raw material powder is
Si: 2.0% by mass or more and 12.0% by mass or less,
Al: 10.0 mass% or less, and balance: alloy containing Fe and inevitable impurities.

  Since the magnetic member powder according to the first embodiment is used as the raw material powder, the ratio Pc of the number Nc of the particles having the circularity C of 0.80 or more to the total number N of the particles in the raw material powder is 50%. % Or more. This ratio Pc is more preferably at least 70%, particularly preferably at least 80%.

  Since the powder for a magnetic member according to the first embodiment is used as the raw material powder, the standard deviation σ when the peak ratio (Pα / Pβ) is measured 10 times in this raw material powder is 3 or more and less than 20. . Preferably, the standard deviation σ is 10 or more and less than 20.

  In the magnetic member powder, the insulating film 12 prevents direct contact between the main part 10 of the particle 8 and the main part 10 of another particle 8 adjacent to the particle 8. Thereby, eddy current loss is suppressed. In this respect, the thickness of the film 12 is preferably equal to or greater than 20 nm, and particularly preferably equal to or greater than 30 nm. The thickness of the film 12 is preferably 500 nm or less, and particularly preferably 100 nm or less, from the viewpoint that the magnetic properties of the main part 10 are not easily inhibited.

  As shown in FIG. 3, the coating 12 covers the entire main part 10. The coating 12 may partially cover the main part 10.

  The particles 8 may have another coating between the main part 10 and the coating 12. The particles 8 may have another coating outside the coating 12.

  A preferred material for the coating 12 is a polymer containing titanium alkoxides and silicon alkoxides. This polymer can be obtained by a polymerization reaction of a mixture of a titanium alkoxide and a silicon alkoxide. Titanium alkoxides are compounds in which at least one alkoxide group is bonded to a titanium atom in one molecule. Silicon alkoxides are compounds in which at least one alkoxide group is bonded to a silicon atom in one molecule. An alkoxide group is a compound in which an organic group is bonded to oxygen having a negative charge. The organic group is a group composed of an organic compound.

  The titanium alkoxide includes a monomer of titanium alkoxide, an oligomer formed by polymerizing a plurality of the monomers, and a compound (also referred to as a precursor) at a stage before titanium alkoxide is generated. The silicon alkoxides include a silicon alkoxide monomer, an oligomer formed by polymerizing a plurality of the monomers, and a compound (also referred to as a precursor) at a stage before the silicon alkoxide is formed.

  Specific examples of the titanium alkoxide include titanium tetramethoxide, titanium tetraethoxide, titanium tetraisopropoxide, titanium tetrabutoxide, titanium tetra-2-ethylhexoxide, and isopropyl tridodecylbenzenesulfonyl titanate.

  Specific examples of silicon alkoxide include tetraethoxysilane, tetramethoxysilane, methyltriethoxysilane, tetraisopropoxysilane, vinyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N- (β-aminoethyl) -γ-amino Propylmethyldimethoxysilane.

  Various coating methods can be adopted for attaching the film 12 to the main part 10. Specific examples of the coating method include a mixing method, a sol-gel method, a spray drier method and a tumbling fluidized bed method.

  A polymer containing a titanium alkoxide and a silicon alkoxide may be diluted with a solvent and provided for coating. Preferred solvents include acetone, methyl ethyl ketone, acetonitrile, methanol, ethanol, isopropyl alcohol, n-butanol, benzene, toluene, hexane, heptane, cyclohexane, chloroform, chlorobenzene, dichlorobenzene, ethyl acetate, ethyl propionate, and tetrahydrofuran. .

  The coating 12 may contain other compounds together with a polymer containing titanium alkoxides and silicon alkoxides. The coating 12 may be formed from a compound other than a polymer containing titanium alkoxides and silicon alkoxides.

[Third embodiment]
FIG. 4 is a sectional view showing particles 14 of a powder for a magnetic member according to still another embodiment of the present invention. In FIG. 4, the symbol L indicates the length of the major axis of the particle 14, and the symbol t indicates the thickness of the particle 14. The length L is greater than the thickness t. In other words, the particles 14 are flat. The material of the particles 14 is the same as the material of the particles 14 shown in FIG.

The method for producing the magnetic member powder is as follows.
(1) a step of obtaining a raw material powder composed of a large number of particles,
And (2) a step of subjecting the particles to flattening. As the raw material powder, the magnetic member powder according to the first embodiment (see FIG. 1) is used. Therefore, the material of this raw material powder is
Si: 2.0% by mass or more and 12.0% by mass or less,
Al: 10.0 mass% or less, and balance: alloy containing Fe and inevitable impurities.

  Since the magnetic member powder according to the first embodiment is used as the raw material powder, the ratio Pc of the number Nc of the particles having the circularity C of 0.80 or more to the total number N of the particles in the raw material powder is 50%. % Or more. This ratio Pc is more preferably at least 70%, particularly preferably at least 80%. The magnetic properties of the powder obtained by subjecting the raw material powder having a high ratio Pc to flattening are superior to the magnetic properties of the powder obtained by subjecting the raw material powder having a small ratio Pc to flattening.

  Since the powder for a magnetic member according to the first embodiment is used as the raw material powder, the standard deviation σ when the peak ratio (Pα / Pβ) is measured 10 times in this raw material powder is 3 or more and less than 20. . Preferably, the standard deviation σ is 10 or more and less than 20.

  The aspect ratio of the magnetic member powder is preferably 10 or more and 300 or less. In a magnetic member using a powder having an aspect ratio of 10 or more, the real part magnetic permeability μ 'in a high-frequency region is sufficiently large, so that the loss is suppressed. In this respect, the aspect ratio is particularly preferably equal to or greater than 50. In a magnetic member using a powder having an aspect ratio of 300 or less, portions where the powders contact each other are suppressed, and loss due to eddy current is suppressed. In this respect, the aspect ratio is particularly preferably equal to or less than 200.

In the measurement of the aspect ratio, the particles 14 are observed by a scanning electron microscope (SEM). The position where the length is maximum in plan view is specified. This length is the length L of the long axis. The length L of the ten particles 14 is measured, and an arithmetic mean value Lav is calculated. The particles 14 are buried in a resin and polished. This polished surface is observed with an optical microscope, and the thickness direction of the particles 14 is specified. Further, the maximum thickness tm and the minimum thickness tn are measured, and the average value of the maximum thickness tm and the minimum thickness tn ((tm + tn) / 2) is calculated. An arithmetic average value tav of the average value ((tm + tn) / 2) of the 50 particles 14 is calculated. The aspect ratio R of this powder is calculated by the following equation.
R = Lav / tav

  In the X-ray diffraction analysis of this powder, a maximum value PA having an angle 2θ of 43 ° or more and less than 44 ° and a maximum value PB having an angle 2θ of 44 ° or more and less than 45 ° can be measured. The maximum value PA is a peak of a phase that contributes to an improvement in coercive force. The maximum value PB is a peak of a phase that contributes to the improvement of the magnetic permeability. As a result of extensive development, the inventors have found that a powder having a ratio PA / PB of 0.00100 or more and 2.00 or less can obtain good magnetic properties. The ratio PA / PB is particularly preferably 0.010 or more. The ratio PA / PB is particularly preferably 1.00 or less. A typical example of the X-ray diffractometer is Rigaku Corporation's fully automatic multipurpose X-ray diffractometer "SmartLab SE".

[Average particle size]
The average particle size D50 of this powder is preferably 20 μm or more and 150 μm or less. A powder having an average particle size D50 of 20 μm or more has excellent fluidity, and therefore can be easily mixed with the matrix resin. In this respect, the average particle diameter D50 is more preferably equal to or greater than 25 μm, and particularly preferably equal to or greater than 30 μm. A magnetic sheet having a small thickness can be obtained from a powder having an average particle diameter D50 of 150 μm or less. This magnetic sheet can be applied to a small electronic device. In this respect, the average particle diameter D50 is more preferably equal to or less than 120 μm, and particularly preferably equal to or less than 100 μm.

  Typical flattening is performed by a media stirring type mill (attritor). Flattening may be performed by mechanical pulverization. The flattened powder may be subjected to strain relief annealing.

  The particles 14 may have a coating similar to the coating 12 of the particles 8 shown in FIG.

  Hereinafter, the effects of the present invention will be clarified by examples, but the present invention should not be construed as being limited based on the description of the examples.

[Experiment 1]
[Example 1]
Raw materials for the component 5 shown in Table 1 were prepared. From this raw material, a powder was produced by atomization. The shape of each particle in this powder was substantially spherical. In this powder, the ratio Pc of the number Nc of particles having a circularity C of 0.80 or more to the total number N of particles was 60%. In this powder, the standard deviation σ when the peak ratio (Pα / Pβ) was measured ten times was 1.39.

[Example 2-30 and Comparative Example 1-10]
Powders of Example 2-30 and Comparative Example 1-10 were produced in the same manner as in Example 1 except that the ratio Pc was as shown in Tables 2 and 3 below.

[Evaluation of magnetic permeability]
The powder was kneaded with the epoxy resin at a temperature of 100 ° C. using a small mixer to obtain a resin composition in which the powder was uniformly dispersed in a resin matrix. The volume ratio between the epoxy resin and the powder was 5: 2. This resin composition was hot-pressed for 5 minutes under the conditions of a pressure of 4 MPa and a temperature of 200 ° C. to obtain a resin molded product. The size of this molded product was 10 mm long × 10 mm wide × 10 mm high. The magnetic permeability μ ′ of this molded product under the conditions of a temperature of 25 ° C. and a frequency of 20 MHz was measured. The results are shown in Tables 1 and 2 below. The magnetic permeability μ ′ was measured by a vector name “Vector Network Analyzer N5245A” manufactured by Agilent Technologies. Each powder was ranked based on the magnetic permeability μ ′ according to the following criteria.
A: 60 or more B: 50 or more and less than 60 C: 40 or more and less than 50 F: Less than 40 The results of ranking are shown in Tables 2 and 3 below.

[Experiment 2]
[Example 31]
Raw materials for the component 16 shown in Table 1 were prepared. From this raw material, a powder was produced by atomization. The shape of each particle in this powder was substantially spherical. In this powder, the ratio Pc of the number Nc of particles having a circularity C of 0.80 or more to the total number N of particles was 61%. In this powder, the standard deviation σ when the peak ratio (Pα / Pβ) was measured 10 times was 1.40.

[Examples 32-60 and Comparative Examples 11-20]
Powders of Examples 32-60 and Comparative Examples 11-20 were produced in the same manner as in Example 31, except that the ratio Pc was as shown in Tables 4 and 5 below.

[Evaluation of magnetic permeability]
The magnetic permeability μ ′ was measured in the same manner as in Experiment 1. The results are shown in Tables 3 and 4 below. Each powder was ranked based on the magnetic permeability μ ′ according to the following criteria.
A: 80 or more B: 70 or more and less than 80 C: 60 or more and less than 70 F: Less than 60 The results of ranking are shown in Tables 4 and 5 below.

[Experiment 3]
[Example 61]
Raw materials for the component 3 shown in Table 1 were prepared. From this raw material, a raw material powder was produced by atomization. The shape of each particle in the raw material powder was substantially spherical. In this raw material powder, the ratio Pc of the number Nc of particles having a circularity C of 0.80 or more to the total number N of particles was 64%. In this raw material powder, the standard deviation σ when the peak ratio (Pα / Pβ) was measured ten times was 1.45. This raw material powder was put into a media stirring type mill (attritor) and pulverized to obtain a flat powder.

[Examples 62-90 and Comparative Examples 21-30]
Powders of Examples 62-90 and Comparative Examples 21-30 were produced in the same manner as in Example 61, except that the ratio Pc of the raw material powder was changed as shown in Tables 6 and 7 below.

[Evaluation of magnetic permeability]
The powder was kneaded with the epoxy resin at a temperature of 100 ° C. using a small mixer to obtain a resin composition in which the powder was uniformly dispersed in a resin matrix. The volume ratio between the epoxy resin and the powder was 5: 2. This resin composition was hot-pressed for 5 minutes under the conditions of a pressure of 4 MPa and a temperature of 200 ° C. to obtain a resin sheet. The size of this sheet was 50 mm long × 20 mm wide × 0.1 mm thick. The magnetic permeability μ ′ of this sheet under the conditions of a temperature of 25 ° C. and a frequency of 20 MHz was measured. The results are shown in Tables 5 and 6 below. The magnetic permeability μ ′ was measured by a vector name “Vector Network Analyzer N5245A” manufactured by Agilent Technologies. Each powder was ranked based on the magnetic permeability μ ′ according to the following criteria.
A: 150 or more B: 140 or more and less than 150 C: 130 or more and less than 140 F: Less than 130 The results of ranking are shown in Tables 6 and 7 below.

[Experiment 4]
[Example 91]
Raw materials for the component 18 shown in Table 1 were prepared. From this raw material, a raw material powder was produced by atomization. The shape of each particle in the raw material powder was substantially spherical. In this raw material powder, the ratio Pc of the number Nc of particles having a circularity C of 0.80 or more to the total number N of particles was 69%. In this raw material powder, the standard deviation σ when the peak ratio (Pα / Pβ) was measured ten times was 1.73. This raw material powder was put into a media stirring type mill (attritor) and pulverized to obtain a flat powder.

[Examples 92-120 and Comparative Examples 31-40]
Powders of Examples 92-120 and Comparative Examples 31-40 were produced in the same manner as in Example 91 except that the ratio Pc of the raw material powder was changed as shown in Tables 8 and 9 below.

[Evaluation of magnetic permeability]
The magnetic permeability μ ′ was measured in the same manner as in Experiment 3. The results are shown in Tables 7 and 8 below. Each powder was ranked based on the magnetic permeability μ ′ according to the following criteria.
A: 180 or more B: 170 or more and less than 180 C: 160 or more and less than 170 F: Less than 160 The results of ranking are shown in Tables 8 and 9 below.

  The superiority of the present invention is clear from the evaluation results shown in Table 2-9.

  The powder according to the present invention is suitable for various magnetic members.

2, 8, 14 ... particles 4 ... magnetic sheet 6 ... matrix 10 ... main part 12 ... film

Claims (6)

A powder for a magnetic member composed of a large number of particles,
The material of each particle is
Si: 2.0% by mass or more and 12.0% by mass or less,
Al: an alloy containing 10.0 mass% or less, and the balance: Fe and unavoidable impurities,
A powder for a magnetic member, wherein the ratio of the number of particles having a circularity of 0.80 or more to the total number of particles is 50% or more.   In the X-ray diffraction analysis of the particles, the standard deviation σ when the ratio (Pα / Pβ) of the diffraction peak Pα on the (220) plane to the diffraction peak Pβ on the (400) plane is measured 10 times is 3 to 20. The powder for a magnetic member according to claim 1, wherein A powder for a magnetic member composed of a large number of particles,
Each particle has a base particle and an insulating coating covering the base particle,
The material of the base particles is
Si: 2.0% by mass or more and 12.0% by mass or less,
Al: an alloy containing 10.0 mass% or less, and the balance: Fe and unavoidable impurities,
A powder for a magnetic member, wherein the ratio of the number of base particles having a circularity of 0.80 or more to the total number of base particles is 50% or more.   When the ratio (Pα / Pβ) of the diffraction peak Pα on the (220) plane to the diffraction peak Pβ on the (400) plane (Pα / Pβ) is measured 10 times in the X-ray diffraction analysis of the base particles, the standard deviation σ is 3 or more. The powder for a magnetic member according to claim 3, which is less than 20. It consists of many particles, and the material of each particle is
Si: 2.0% by mass or more and 12.0% by mass or less,
Al: 10.0 mass% or less, and balance: an alloy containing Fe and unavoidable impurities, wherein the ratio of the number of particles having a circularity of 0.80 or more to the total number of particles is 50% or more. Powder for magnetic members obtained by subjecting powder to flattening.   In the X-ray diffraction analysis of the particles of the raw material powder, the standard deviation σ when the ratio (Pα / Pβ) of the diffraction peak Pα on the (220) plane to the diffraction peak Pβ on the (400) plane is measured 10 times is: The powder for a magnetic member according to claim 5, which is 3 or more and less than 20.

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