JP2020045569A - Soft magnetic alloy powder, powder magnetic core and magnetic component - Google Patents

Abstract

To provide a soft magnetic alloy powder suitable for a powder magnetic core having good voltage resistance.SOLUTION: There is provided a soft magnetic alloy powder containing a plurality of soft magnetic alloy powder 2 represented by a composition formula, (FeX1αX2β)MaBbPcSidCe, wherein X1 is one or more selected from Co and Ni, X2 is one or more selected from Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O and a rare earth element, 0.020≤a≤0.14, 0.020<b≤0.20, 0<c≤0.15, 0≤d≤0.060, 0≤e≤0.040, α≥0, β≥0, 0≤α+β≤0.50, an initial microcrystal has a nano heterostructure existing in an amorphous material and a surface of the soft magnetic alloy powder 2 is coated with a coating part 10 containing one or more compounds selected from P, Si, Bi and Zn.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a soft magnetic alloy powder, a dust core, and a magnetic component.

  Transformers, choke coils, inductors, and the like are known as magnetic components used in power supply circuits of various electronic devices.

  Such a magnetic component has a configuration in which a coil (winding), which is an electric conductor, is arranged around or inside a magnetic core (core) exhibiting predetermined magnetic characteristics.

  Magnetic cores provided in magnetic components such as inductors are required to be smaller and have higher performance. As a soft magnetic material having good magnetic properties used for such a magnetic core, a nanocrystalline alloy based on iron (Fe) is exemplified. A nanocrystalline alloy is an alloy in which nanometer-order microcrystals are precipitated in an amorphous alloy by heat-treating the amorphous alloy. For example, Patent Literature 1 describes a ribbon of a soft magnetic amorphous alloy based on Fe-BM (M = Ti, Zr, Hf, V, Nb, Ta, Mo, W). According to Patent Document 1, this soft magnetic amorphous alloy has a higher saturation magnetic flux density than commercially available Fe amorphous.

  By the way, when the magnetic core is obtained as a dust core, it is necessary to make such a soft magnetic alloy into a powder form and to perform compression molding. In such a dust core, the ratio (filling rate) of the magnetic component is increased in order to improve the magnetic characteristics. However, since soft magnetic alloys have low insulating properties, when particles made of a soft magnetic alloy are in contact with each other, when a voltage is applied to a magnetic component, a current flowing between the contacting particles (an eddy current ) Causes a large loss, resulting in a large core loss of the dust core.

  Therefore, in order to suppress such eddy currents, an insulating coating is formed on the surface of the soft magnetic alloy particles. For example, Patent Document 2 discloses that an insulating coating layer is formed on the surface of an Fe-based amorphous alloy powder by softening powder glass containing an oxide of phosphorus (P) by mechanical friction.

Japanese Patent No. 3342767 JP 2015-132010 A

  In Patent Literature 2, an Fe-based amorphous alloy powder having an insulating coating layer formed thereon is mixed with a resin and formed into a dust core by compression molding. If the thickness of the insulating coating layer is increased, the withstand voltage of the dust core is improved, but the filling ratio of the magnetic component is reduced, so that the magnetic characteristics are deteriorated. Therefore, in order to obtain good magnetic properties, it is necessary to improve the withstand voltage of the entire soft magnetic alloy powder on which the insulating coating layer is formed.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a dust core having good withstand voltage, a magnetic component including the dust core, and a soft magnetic alloy powder suitable for the dust core. .

  The present inventors have found that by providing a coating portion on soft magnetic alloy particles made of a soft magnetic alloy having a specific composition, the withstand voltage of the entire powder including the soft magnetic alloy particles is improved, and The invention has been completed.

That is, aspects of the present invention
[1] Composition formula _{(Fe (1- (α + β} )) X1 α X2 β) (1- (a + b + c + d + e)) M a B b P c Si d C e made of a soft magnetic alloy represented by the soft magnetic alloy grains A soft magnetic alloy powder containing a plurality of
X1 is one or more selected from the group consisting of Co and Ni;
X2 is at least one selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O and a rare earth element;
M is one or more selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W and V;
a, b, c, d, e, α and β are
0.020 ≦ a ≦ 0.14,
0.020 <b ≦ 0.20,
0 <c ≦ 0.15,
0 ≦ d ≦ 0.060,
0 ≦ e ≦ 0.040,
α ≧ 0,
β ≧ 0,
Satisfying the relationship 0 ≦ α + β ≦ 0.50,
The soft magnetic alloy has a nanoheterostructure in which the initial crystallites exist in the amorphous state,
The surface of the soft magnetic alloy particles is covered with a coating,
The covering portion is a soft magnetic alloy powder containing a compound of at least one element selected from the group consisting of P, Si, Bi and Zn.

  [2] The soft magnetic alloy powder according to [1], wherein the average particle diameter of the initial microcrystal is 0.3 nm or more and 10 nm or less.

[3] the composition formula _{(Fe (1- (α + β} )) X1 α X2 β) (1- (a + b + c + d + e)) M a B b P c Si d C made of a soft magnetic alloy represented by _e soft magnetic alloy grains A soft magnetic alloy powder containing a plurality of
X1 is one or more selected from the group consisting of Co and Ni;
X2 is at least one selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O and a rare earth element;
M is one or more selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W and V;
a, b, c, d, e, α and β are
0.020 ≦ a ≦ 0.14,
0.020 <b ≦ 0.20,
0 <c ≦ 0.15,
0 ≦ d ≦ 0.060,
0 ≦ e ≦ 0.040,
α ≧ 0,
β ≧ 0,
Satisfying the relationship 0 ≦ α + β ≦ 0.50,
The soft magnetic alloy has Fe-based nanocrystals,
The surface of the soft magnetic alloy particles is covered with a coating,
The covering portion is a soft magnetic alloy powder containing a compound of at least one element selected from the group consisting of P, Si, Bi and Zn.

  [4] The soft magnetic alloy powder according to [3], wherein the average particle size of the Fe-based nanocrystals is 5 nm or more and 30 nm or less.

  [5] A dust core made of the soft magnetic alloy powder according to any one of [1] to [4].

  [6] A magnetic component including the dust core according to [5].

  According to the present invention, it is possible to provide a dust core having good withstand voltage, a magnetic component including the dust core, and a soft magnetic alloy powder suitable for the dust core.

FIG. 1 is a schematic cross-sectional view of the coated particles constituting the soft magnetic alloy powder according to the present embodiment. FIG. 2 is a schematic cross-sectional view showing a configuration of a powder coating apparatus used for forming a coating portion.

Hereinafter, the present invention will be described in detail in the following order based on specific embodiments illustrated in the drawings.
1. Soft magnetic alloy powder 1.1. Soft magnetic alloy 1.1.1. First viewpoint 1.1.2. Second viewpoint 1.2. Covering part 2. 2. dust core Magnetic components4. Manufacturing method of dust core 4.1. Method for producing soft magnetic alloy powder 4.2. Manufacturing method of dust core

(1. Soft magnetic alloy powder)
As shown in FIG. 1, the soft magnetic alloy powder according to the present embodiment includes a plurality of coated particles 1 in which a coating portion 10 is formed on the surface of soft magnetic alloy particles 2. Assuming that the number ratio of particles contained in the soft magnetic alloy powder is 100%, the number ratio of the coated particles is preferably 90% or more, and more preferably 95% or more. The shape of the soft magnetic alloy particles 2 is not particularly limited, but is usually spherical.

  Further, the average particle diameter (D50) of the soft magnetic alloy powder according to the present embodiment may be selected according to the use and the material. In the present embodiment, the average particle diameter (D50) is preferably in the range of 0.3 to 100 μm. By setting the average particle size of the soft magnetic alloy powder within the above range, it is easy to maintain sufficient formability or predetermined magnetic characteristics. The method for measuring the average particle diameter is not particularly limited, but it is preferable to use a laser diffraction scattering method.

  In the present embodiment, the soft magnetic alloy powder may include only soft magnetic alloy particles of the same material, or may include soft magnetic alloy particles of different materials. The different materials include, for example, a case where elements constituting the soft magnetic alloy are different, a case where the composition is different even if the constituent elements are the same, and the like.

(1.1. Soft magnetic alloy)
The soft magnetic alloy particles are made of a soft magnetic alloy having a predetermined structure and composition. In the present embodiment, the soft magnetic alloy will be described by dividing it into a soft magnetic alloy according to a first aspect and a soft magnetic alloy according to a second aspect. The difference between the soft magnetic alloy according to the first aspect and the soft magnetic alloy according to the second aspect is a difference in the structure of the soft magnetic alloy, and the composition is common.

(1.1.1. First viewpoint)
The soft magnetic alloy according to the first aspect has a nanoheterostructure in which initial microcrystals exist in an amorphous state. Such a structure is a structure in which a large number of microcrystals are precipitated and dispersed in an amorphous alloy obtained by rapidly cooling a molten metal in which a raw material of a soft magnetic alloy is dissolved. Therefore, the average particle size of the initial microcrystals is very small. In the present embodiment, it is preferable that the average particle diameter of the initial microcrystal is 0.3 nm or more and 10 nm or less.

  A soft magnetic alloy having such a nanoheterostructure is heat-treated under predetermined conditions to grow initial microcrystals, and to form a soft magnetic alloy (soft magnetic material having Fe-based nanocrystals) according to a second aspect described later. Alloy).

  Subsequently, the composition of the soft magnetic alloy according to the first aspect will be described in detail.

Soft magnetic alloy according to the first aspect, a composition formula _{(Fe (1- (α + β} )) X1 α X2 β) represented by _{(1- (a + b + c} + d + e)) M a B b P c Si d C e, Fe is It is a soft magnetic alloy that exists at a relatively high concentration.

  In the above composition formula, M is at least one element selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W and V.

  A indicates the content of M, and a satisfies 0.020 ≦ a ≦ 0.14. The content (a) of M is preferably 0.040 or more, and more preferably 0.050 or more. Further, the content (a) of M is preferably 0.10 or less, and more preferably 0.080 or less.

  If a is too small, a crystal phase composed of crystals having a grain size larger than 30 nm is likely to be formed in the soft magnetic alloy. When such a crystal phase is generated, it is impossible to precipitate Fe-based nanocrystals by heat treatment. As a result, the specific resistance of the soft magnetic alloy tends to decrease and the coercive force tends to increase. On the other hand, when a is too large, the saturation magnetization of the powder tends to decrease easily.

  In the above composition formula, b indicates the content of B (boron), and b satisfies 0.020 <b ≦ 0.20. The content (b) of B is preferably 0.025 or more, more preferably 0.060 or more, and even more preferably 0.080 or more. Further, the content (b) of B is preferably 0.15 or less, more preferably 0.12 or less.

  If b is too small, a crystalline phase composed of crystals having a grain size larger than 30 nm is likely to be formed in the soft magnetic alloy. When such a crystal phase is generated, it is impossible to precipitate Fe-based nanocrystals by heat treatment. As a result, the specific resistance of the soft magnetic alloy tends to decrease and the coercive force tends to increase. On the other hand, if b is too large, the saturation magnetization of the powder tends to decrease.

  In the above composition formula, c indicates the content of P (phosphorus), and c satisfies 0 <c ≦ 0.15. The P content (c) is preferably at least 0.005, and more preferably at least 0.010. Further, the P content (c) is preferably 0.100 or less.

  When c is within the above range, the specific resistance of the soft magnetic alloy tends to increase and the coercive force tends to decrease. If c is too small, the above effects tend to be hardly obtained. On the other hand, if c is too large, the saturation magnetization of the powder tends to decrease.

  In the above composition formula, d indicates the content of Si (silicon), and d satisfies 0 ≦ d ≦ 0.060. That is, the soft magnetic alloy may not contain Si. The Si content (d) is preferably 0.001 or more, more preferably 0.005 or more. Further, the content (d) of Si is preferably 0.040 or less.

  When d is within the above range, the specific resistance of the soft magnetic alloy tends to be particularly improved, and the coercive force tends to be reduced. On the other hand, if d is too large, the coercive force of the soft magnetic alloy tends to increase.

  In the above composition formula, e indicates the content of C (carbon), and e satisfies 0 ≦ e ≦ 0.040. That is, the soft magnetic alloy may not contain C. The content (e) of C is preferably 0.001 or more. Further, the content (e) of C is preferably 0.035 or less, and more preferably 0.030 or less.

  When e is within the above range, the coercive force of the soft magnetic alloy tends to be particularly low. If e is too large, the specific resistance of the soft magnetic alloy tends to decrease, and the coercive force tends to increase.

  In the above composition formula, 1- (a + b + c + d + e) indicates the content of Fe (iron). The content of Fe is not particularly limited, but in this embodiment, the content of Fe (1- (a + b + c + d + e)) is preferably 0.73 or more and 0.95 or less. By setting the Fe content within the above range, a crystal phase composed of crystals having a grain size larger than 30 nm is less likely to be generated. As a result, a soft magnetic alloy in which Fe-based nanocrystals are precipitated by heat treatment tends to be easily obtained.

  Further, in the soft magnetic alloy according to the first aspect, as shown in the above composition formula, a part of Fe may be compositionally replaced with X1 and / or X2.

  X1 is one or more elements selected from the group consisting of Co and Ni. In the above composition formula, α indicates the content of X1, and in the present embodiment, α is 0 or more. That is, the soft magnetic alloy does not have to contain X1.

  Further, when the total number of atoms of the composition is 100 at%, the number of X 1 atoms is preferably 40 at% or less. That is, it is preferable to satisfy 0 ≦ α {1− (a + b + c + d + e)} ≦ 0.40.

  X2 is one or more elements selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O and rare earth elements. In the above composition formula, β indicates the content of X2, and in the present embodiment, β is 0 or more. That is, the soft magnetic alloy may not contain X2.

  Further, when the total number of atoms of the composition is 100 at%, the number of X 2 atoms is preferably 3.0 at% or less. That is, it is preferable to satisfy 0 ≦ β {1- (a + b + c + d + e)} ≦ 0.030.

  Further, the range (substitution amount) in which X1 and / or X2 substitutes for Fe is set to not more than half of the total number of atoms of Fe in terms of the number of atoms. That is, 0 ≦ α + β ≦ 0.50. If α + β is too large, it tends to be difficult to obtain a soft magnetic alloy in which Fe-based nanocrystals are precipitated by heat treatment.

  The soft magnetic alloy according to the first aspect may include elements other than the above as inevitable impurities. For example, elements other than the above may be included in a total of 0.1% by weight or less based on 100% by weight of the soft magnetic alloy.

(1.1.2. Second viewpoint)
The configuration of the soft magnetic alloy according to the second aspect is the same as that of the soft magnetic alloy according to the first aspect except for the structure thereof, and a duplicate description will be omitted. That is, the description regarding the composition of the soft magnetic alloy according to the first aspect also applies to the soft magnetic alloy according to the second aspect.

  The soft magnetic alloy according to the second aspect has Fe-based nanocrystals. The Fe-based nanocrystals are Fe crystals having a particle size on the order of nanometers and a crystal structure of bcc (body-centered cubic lattice structure). In the soft magnetic alloy, many Fe-based nanocrystals are precipitated and dispersed in the amorphous phase. In the present embodiment, the Fe-based nanocrystal is preferably obtained by heat-treating the powder containing the soft magnetic alloy according to the first aspect to grow the initial microcrystal.

  Therefore, the average particle size of the Fe-based nanocrystals tends to be slightly larger than the average particle size of the initial microcrystals. In the present embodiment, the average particle diameter of the Fe-based nanocrystal is preferably 5 nm or more and 30 nm or less. A soft magnetic alloy in which Fe-based nanocrystals are dispersed in an amorphous state can easily obtain high saturation magnetization and low coercive force.

(1.2. Covering part)
The covering portion 10 is formed so as to cover the surface of the soft magnetic metal particle 2 as shown in FIG. Further, in the present embodiment, that the surface is covered with the substance refers to a form in which the substance is fixed so as to cover the portion in contact with the surface. Further, the coating portion covering the soft magnetic alloy particles may cover at least a part of the surface of the particles, but preferably covers the entire surface. Further, the coating may cover the surface of the particles continuously or intermittently.

  The coating portion 10 is not particularly limited as long as the coating portion 10 can insulate the soft magnetic alloy particles constituting the soft magnetic alloy powder. In the present embodiment, the covering portion 10 preferably contains a compound of one or more elements selected from the group consisting of P, Si, Bi, and Zn, and particularly preferably contains a compound containing P. . Further, the compound is more preferably an oxide, and particularly preferably an oxide glass. By making the covering portion have the above-described configuration, the adhesion to the element segregated in the amorphous portion of the soft magnetic alloy is improved, and the insulating property of the soft magnetic alloy powder is improved.

  Further, it is preferable that a compound of one or more elements selected from the group consisting of P, Si, Bi, and Zn is contained as a main component in the coating portion 10. “Including an oxide of one or more elements selected from the group consisting of P, Si, Bi, and Zn as a main component” refers to the total amount of elements excluding oxygen among the elements included in the coating portion 10. When it is 100% by mass, it means that the total amount of one or more elements selected from the group consisting of P, Si, Bi, and Zn is the largest. In this embodiment, the total amount of these elements is preferably 50% by mass or more, and more preferably 60% by mass or more.

The oxide glass is not particularly limited. For example, phosphate (P ₂ O ₅ ) -based glass, bismuthate (Bi ₂ O ₃ ) -based glass, borosilicate (B ₂ O ₃ —SiO ₂ ) -based glass Etc. are exemplified.

The P ₂ O ₅ based _glass, glass is preferably P 2 _{O 5} is contained more than _{50wt%, P 2 O 5 -ZnO} -R 2 O-Al 2 O 3 based glass and the like. “R” indicates an alkali metal.

The Bi ₂ O ₃ based glass, glass is preferable _{that Bi} 2 _{O 3} is contained more than _{50wt%, Bi 2 O 3 -ZnO} -B 2 O 3 -SiO 2 based glass and the like.

The B ₂ O ₃ -SiO ₂ -based _glass, B 2 _{O 3} is contained more than 10 wt%, the glass is preferably SiO ₂ is contained more than _{10wt%, BaO-ZnO-B} 2 O 3 -SiO 2 -Al 2 O ₃ based glass and the like.

  By having such an insulating coating portion, the insulating properties of the particles are further increased, so that the withstand voltage of the dust core made of the soft magnetic alloy powder containing the coated particles is improved.

  The components contained in the coating can be identified from information such as lattice constants obtained by elemental analysis by EDS using TEM such as STEM, elemental analysis by EELS, FFT analysis of TEM images, and the like.

  The thickness of the covering portion 10 is not particularly limited as long as the above effects are obtained. In the present embodiment, the thickness is preferably 5 nm or more and 200 nm or less. Further, the thickness is preferably 150 nm or less, and more preferably 50 nm or less.

(2. Powder magnetic core)
The dust core according to the present embodiment is not particularly limited as long as it is made of the above-described soft magnetic alloy powder and is formed to have a predetermined shape. In the present embodiment, the soft magnetic alloy powder includes a soft magnetic alloy powder and a resin as a binder, and the soft magnetic alloy particles constituting the soft magnetic alloy powder are fixed to a predetermined shape by bonding via the resin. Further, the dust core may be made of a mixed powder of the above-mentioned soft magnetic alloy powder and another magnetic powder, and may be formed in a predetermined shape.

(3. Magnetic parts)
The magnetic component according to the present embodiment is not particularly limited as long as it has the above-mentioned dust core. For example, it may be a magnetic component in which an air-core coil around which a wire is wound is buried inside a dust core having a predetermined shape, or a predetermined number of turns of a wire are wound around the surface of a dust core having a predetermined shape. The magnetic component may be a turned magnetic component. Since the magnetic component according to the present embodiment has good withstand voltage, it is suitable for a power inductor used in a power supply circuit.

(4. Manufacturing method of dust core)
Subsequently, a method of manufacturing the dust core provided in the magnetic component will be described. First, a method for producing a soft magnetic alloy powder constituting a dust core will be described.

(4.1. Method for producing soft magnetic alloy powder)
The soft magnetic alloy powder according to the present embodiment can be obtained by using a method similar to a known method for manufacturing a soft magnetic alloy powder. Specifically, it can be manufactured using a gas atomizing method, a water atomizing method, a rotating disk method, or the like. Further, a ribbon obtained by a single roll method or the like may be manufactured by mechanically pulverizing the ribbon. Among these, it is preferable to use a gas atomizing method from the viewpoint that a soft magnetic alloy powder having desired magnetic properties is easily obtained.

  In the gas atomization method, first, a molten metal in which the raw material of the soft magnetic alloy constituting the soft magnetic alloy powder is melted is obtained. A raw material (pure metal or the like) of each metal element contained in the soft magnetic alloy is prepared, weighed so as to have a composition of the finally obtained soft magnetic alloy, and the raw material is dissolved. The method of dissolving the raw material of the metal element is not particularly limited. For example, a method of evacuating in a chamber of an atomizing device and then dissolving by high-frequency heating is exemplified. The temperature at the time of melting may be determined in consideration of the melting point of each metal element, and may be, for example, 1200 to 1500 ° C.

  The obtained molten metal is supplied into the chamber as a linear continuous fluid through a nozzle provided at the bottom of the crucible, and a high-pressure gas is sprayed on the supplied molten metal to form droplets of the molten metal and rapidly cool the molten metal. Obtain a fine powder. The gas injection temperature, the pressure in the chamber, and the like may be determined in accordance with the conditions under which the Fe-based nanocrystals easily precipitate in the amorphous phase in the heat treatment described below. The particle size can be adjusted by sieving or airflow classification.

  The resulting powder is a soft magnetic alloy having a nanoheterostructure in which initial microcrystals exist in an amorphous state, that is, a soft magnetic alloy according to the first aspect, in order to easily precipitate Fe-based nanocrystals by a heat treatment described below. It is preferable to be composed of an alloy. However, if Fe-based nanocrystals are precipitated by the heat treatment described below, the obtained powder may be composed of an amorphous alloy in which each metal element is uniformly dispersed in the amorphous.

  In this embodiment, when a crystal having a grain size larger than 30 nm is present in the soft magnetic alloy before the heat treatment, it is determined that a crystal phase is present, and a crystal having a grain size larger than 30 nm is present. If not, it is determined to be amorphous. It should be noted that whether or not crystals having a particle size larger than 30 nm exist in the soft magnetic alloy may be evaluated by a known method. For example, X-ray diffraction measurement, observation with a transmission electron microscope, and the like are exemplified. When a transmission electron microscope (TEM) is used, it can be confirmed by obtaining a selected area diffraction image and a nanobeam diffraction image. When a selected area diffraction image or a nanobeam diffraction image is used, ring-shaped diffraction is formed when the diffraction pattern is amorphous, whereas diffraction spots due to the crystal structure are formed when the diffraction pattern is not amorphous. It is formed.

The method of observing the presence or absence of the initial microcrystals and the average particle size is not particularly limited, and may be evaluated by a known method. For example, it can be confirmed by using a transmission electron microscope (TEM) to obtain a bright-field image or a high-resolution image of a sample sliced by ion milling. Specifically, by visually observing a bright field image or a high-resolution image obtained at a magnification of 1.00 × 10 ^{5 to} 3.00 × 10 ⁵ , the presence or absence of the initial microcrystals and the average particle size can be evaluated. .

  Next, the obtained powder is heat-treated. The heat treatment prevents the particles from sintering and coarsening the powder, promotes the diffusion of the elements that make up the soft magnetic alloy, and achieves a thermodynamic equilibrium state in a short time. The strain and stress existing in the alloy can be removed. As a result, it becomes easy to obtain a soft magnetic alloy on which Fe-based nanocrystals are precipitated, that is, a powder composed of the soft magnetic alloy according to the second aspect.

  In the present embodiment, the heat treatment condition is not particularly limited as long as it is a condition under which Fe-based nanocrystals are easily precipitated. For example, the heat treatment temperature can be 400 to 700 ° C., and the holding time can be 0.5 to 10 hours.

  After the heat treatment, a powder containing a soft magnetic alloy on which Fe-based nanocrystals are precipitated, that is, soft magnetic alloy particles made of the soft magnetic alloy according to the second aspect is obtained.

  Subsequently, a coating is formed on the soft magnetic alloy particles contained in the powder after the heat treatment. The method for forming the coating portion is not particularly limited, and a known method can be employed. The soft magnetic alloy particles may be subjected to a wet treatment to form the covering portion, or may be subjected to a dry treatment to form the covering portion.

  Further, a coating may be formed on the soft magnetic alloy powder before the heat treatment. That is, the coating may be formed on the soft magnetic alloy particles made of the soft magnetic alloy according to the first aspect.

  In this embodiment, it can be formed by a coating method using a mechanochemical, a phosphate treatment method, a sol-gel method, or the like. In the coating method using mechanochemical, for example, a powder coating apparatus 100 shown in FIG. 2 is used. A mixed powder of a soft magnetic alloy powder and a powdery coating material of a material (such as a compound of P, Si, Bi, and Zn) constituting a coating portion is charged into a container 101 of a powder coating apparatus. After the charging, the container 101 is rotated, whereby the mixture 50 of the soft magnetic alloy powder and the mixed powder is compressed between the grinder 102 and the inner wall of the container 101 to generate friction and generate heat. The powdery coating material is softened by the generated frictional heat, and is fixed to the surface of the soft magnetic alloy particles by a compressing action to form a coating portion.

  In the coating method using mechanochemical, the frictional heat generated is controlled by adjusting the rotation speed of the container, the distance between the grinder and the inner wall of the container, and the mixture of the soft magnetic alloy powder and the mixed powder. Temperature can be controlled. In the present embodiment, the temperature is preferably 50 ° C. or more and 150 ° C. or less. By setting the temperature in such a temperature range, the coating portion can be easily formed so as to cover the surface of the soft magnetic alloy particles.

(4.2. Manufacturing method of dust core)
The dust core is manufactured using the above soft magnetic alloy powder. A specific manufacturing method is not particularly limited, and a known method can be employed. First, a soft magnetic alloy powder containing soft magnetic alloy particles having a coating portion is mixed with a known resin as a binder to obtain a mixture. If necessary, the obtained mixture may be used as granulated powder. Then, the mixture or the granulated powder is filled in a mold and compression-molded to obtain a compact having the shape of the dust core to be produced. By subjecting the obtained molded body to heat treatment at, for example, 50 to 200 ° C., a dust core having a predetermined shape in which the resin is cured and the soft magnetic alloy particles are fixed via the resin is obtained. By winding a wire around the obtained dust core a predetermined number of times, a magnetic component such as an inductor can be obtained.

  Further, the above mixture or granulated powder, and an air core coil formed by winding a wire a predetermined number of times, may be filled in a mold and compression molded to obtain a molded body in which the coil is embedded. Good. By performing a heat treatment on the obtained molded body, a dust core having a predetermined shape in which the coil is embedded is obtained. Since such a dust core has a coil embedded therein, it functions as a magnetic component such as an inductor.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and may be modified in various forms within the scope of the present invention.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Experimental Examples 1 to 45)
First, a raw metal of a soft magnetic alloy was prepared. The prepared raw metal was weighed so as to have the composition shown in Table 1, and stored in a crucible arranged in an atomizing device. Subsequently, after evacuating the chamber, the crucible is heated by high-frequency induction using a work coil provided outside the crucible, and the raw metal in the crucible is melted and mixed to form a 1250 ° C. molten metal (molten metal). Obtained.

  The obtained molten metal was supplied into the chamber as a linear continuous fluid through a nozzle provided at the bottom of the crucible, and a gas was sprayed on the supplied molten metal to obtain a powder. The gas injection temperature was 1250 ° C., and the pressure in the chamber was 1 hPa. In addition, the average particle diameter (D50) of the obtained powder was 20 μm.

  X-ray diffraction measurement was performed on the obtained powder to confirm the presence or absence of crystals having a particle size larger than 30 nm. If there is no crystal having a grain size larger than 30 nm, it is determined that the soft magnetic alloy constituting the powder is composed of an amorphous phase, and if there is a crystal having a grain size larger than 30 nm, the soft magnetic alloy is soft. It was determined that the magnetic alloy consisted of a crystalline phase. Table 1 shows the results.

  Subsequently, the obtained powder was heat-treated. The heat treatment conditions were a heat treatment temperature of 600 ° C. and a holding time of 1 hour. X-ray diffraction measurement and observation by TEM were performed on the powder after the heat treatment, and the presence or absence of Fe-based nanocrystals was evaluated. Table 1 shows the results. In all samples of the examples in which Fe-based nanocrystals were present, it was confirmed that the crystal structure of the Fe-based nanocrystals was a bcc structure and the average particle size was 5 to 30 nm.

The coercive force (Hc) and the saturation magnetization (σs) of the heat-treated powder were measured. The coercive force was measured by placing 20 mg of powder in a plastic case of φ6 mm × 5 mm, melting and solidifying paraffin, and fixing it using a coercive force meter (K-HC1000) manufactured by Tohoku Special Steel. The measurement magnetic field was 150 kA / m. In this example, a sample having a coercive force of 350 A / m or less was regarded as good. Table 1 shows the results. The saturation magnetization was measured using VSM (vibrating sample magnetometer) manufactured by Tamagawa Seisakusho. In this embodiment, the saturation magnetization was good sample is 150A ^· m 2 / kg or more. Table 1 shows the results.

  Subsequently, the powder after the heat treatment is put into a container of a powder coating device together with the powdered glass (coating material), and the powdered glass is coated on the surface of the particles to form a coating portion. A powder was obtained. The addition amount of the powdered glass was set to 0.5 wt% with respect to 100 wt% of the powder after the heat treatment. The thickness of the coating was 50 nm.

Powder glass composition was phosphate type glass is a _{P 2 O 5 -ZnO-R 2} O-Al 2 O 3. The specific composition was 50 wt% of P ₂ O ₅ , 12 wt% of ZnO, 20 wt% of R ₂ O, 6 wt% of Al ₂ O ₃ , and the balance was a minor component.

Note that the present inventors have proposed a glass having a composition in which P ₂ O ₅ is 60 wt%, ZnO is 20 wt%, R ₂ O is 10 wt%, Al ₂ O ₃ is 5 wt%, and the balance is a subcomponent. _A similar experiment was performed on glass having a composition in which ₂ O ₅ was 60 wt%, ZnO was 20 wt%, R ₂ O was 10 wt%, Al ₂ O ₃ was 5 wt%, and the balance was a subcomponent. It has been confirmed that results similar to the results can be obtained.

Next, the soft magnetic alloy powder on which the coating was formed was solidified, and the resistivity of the powder was evaluated. The resistivity of the powder was measured by applying a pressure of 0.6 t / cm ² using a powder resistance measuring device. In this embodiment, the sample resistivity is 10 ⁶ [Omega] cm or more and "◎", the sample is 10 ⁵ [Omega] cm or more as "○", and the sample is 10 ⁴ [Omega] cm or more as "△", 10 ⁴ [Omega] cm Samples that were less than were rated "x". Table 1 shows the results.

Subsequently, a dust core was prepared. The total amount of the epoxy resin as the thermosetting resin and the imide resin as the curing agent was weighed so as to be 3 wt% with respect to 100 wt% of the obtained soft magnetic alloy powder, and added to acetone to form a solution. It was mixed with a soft magnetic alloy powder. After mixing, the granules obtained by volatilizing the acetone were sized with a 355 μm mesh. This was filled in a toroidal mold having an outer diameter of 11 mm and an inner diameter of 6.5 mm, and was pressed at a molding pressure of 3.0 t / cm ² to obtain a compact of a dust core. The resin was hardened at 180 ° C. for 1 hour to obtain a dust core.

  A voltage was applied above and below the sample of the obtained dust core using a source meter, and a voltage value at which a current of 1 mA flowed was regarded as a withstand voltage. In this example, a sample having a withstand voltage of 100 V / mm or more was evaluated as good. Table 1 shows the results.

  From Table 1, it was confirmed that when the content of each component was within the above-described range and the powder had a nanoheterostructure or an Fe-based nanocrystal, the characteristics of the powder and the dust core were good.

  On the other hand, when the content of each component was out of the above-mentioned range, or when it did not have a nanoheterostructure or Fe-based nanocrystal, it was confirmed that the magnetic properties of the powder were inferior.

(Experimental Examples 46 to 72)
In the samples of Experimental Examples 1, 4, and 8, soft magnetic alloy powders were prepared in the same manner as in Experimental Examples 4, 8, and 10, except that “M” in the composition formula was changed to an element shown in Table 2. Evaluations similar to 1, 4, and 8 were performed. Using the obtained powder, a dust core was produced in the same manner as in Experimental Examples 1, 4, and 8, and the same evaluation as in Experimental Examples 1, 4, and 8 was performed. Table 2 shows the results.

  From Table 2, it was confirmed that the characteristics of the powder and the dust core were good regardless of the composition and content of the M element.

(Experimental Examples 73 to 126)
In the sample of Experimental Example 1, a soft magnetic alloy powder was prepared in the same manner as in Experimental Example 1 except that the elements and contents of “X1” and “X2” in the composition formula were changed to the elements and contents shown in Table 3. The same evaluation as in Experimental Example 1 was performed. A dust core was prepared using the obtained powder in the same manner as in Experimental Example 1, and the same evaluation as in Experimental Example 1 was performed. Table 3 shows the results.

  From Table 3, it was confirmed that the characteristics of the powder and the dust core were good irrespective of the composition and content of the X1 element and the X2 element.

(Experimental examples 127 to 147)
In the sample of Experimental Example 1, the composition of the coating material was set to the composition shown in Table 4, and the thickness of the coating formed using the coating material was set to the value shown in Table 4. A magnetic alloy powder was prepared and evaluated in the same manner as in Experimental Example 1. A dust core was prepared using the obtained powder in the same manner as in Experimental Example 1, and the same evaluation as in Experimental Example 1 was performed. Table 4 shows the results. Note that no coating was formed on the sample of Experimental Example 127.

Further, in this embodiment, the _{Bi 2 O 3 -ZnO-B 2} O 3 -SiO 2 system glass powder as bismuthate glass, _Bi 2 _{O 3} is 80 wt%, ZnO is _10wt%, B 2 _{O 3} Was 5 wt% and SiO ₂ was 5 wt%. A similar experiment was performed on a glass having another composition as the bismuthate-based glass, and it was confirmed that the same result as that described later was obtained.

Further, in this embodiment, in _{BaO-ZnO-B 2 O 3} -SiO 2 -Al 2 O 3 based glass powder as borosilicate glass, BaO is 8 wt%, ZnO is 23 _wt%, the B 2 _{O 3} 19% by weight, 16% by weight of SiO ₂ , 6% by weight of Al ₂ O ₃ , and the balance was a minor component. Similar experiments were performed on glasses having other compositions as borosilicate glasses, and it was confirmed that results similar to the results described later were obtained.

  From Table 4, it was confirmed that the resistivity of the powder and the withstand voltage of the dust core were improved as the thickness of the coating portion was increased. Also, it was confirmed that the powder resistivity and the withstand voltage of the dust core were good regardless of the composition of the coating material.

(Experimental examples 148 to 161)
A soft magnetic alloy powder was prepared in the same manner as in Experimental Example 1 except that the temperature of the molten metal at the time of atomization and the heat treatment conditions of the powder obtained by atomizing were set to the conditions shown in Table 5 in the sample of Experimental Example 1. The same evaluation as in Example 1 was performed. A dust core was prepared using the obtained powder in the same manner as in Experimental Example 1, and the same evaluation as in Experimental Example 1 was performed. Table 5 shows the results.

  From Table 5, it can be seen that the powder having a nanoheterostructure having initial microcrystals and the powder having Fe-based nanocrystals after heat treatment have the same resistance as the powder regardless of the average particle size of the initial microcrystals and the average particle size of the Fe-based nanocrystals. It was confirmed that the ratio and the withstand voltage of the dust core were good.

DESCRIPTION OF SYMBOLS 1 ... Coated particle 10 ... Coated part 2: Soft magnetic alloy particle

Claims (6)

Composition formula _{(Fe (1- (α + β} )) X1 α X2 β) (1- (a + b + c + d + e)) M a B b P c Si d C e in soft including a plurality of soft magnetic alloy particles made of a soft magnetic alloy represented by A magnetic alloy powder,
The soft magnetic alloy powder has an average particle diameter (D50) of 0.3 to 100 μm,
X1 is one or more selected from the group consisting of Co and Ni;
X2 is at least one selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O and a rare earth element;
M is one or more selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W and V;
a, b, c, d, e, α and β are
0.020 ≦ a ≦ 0.14,
0.020 <b ≦ 0.20,
0 <c ≦ 0.15,
0 ≦ d ≦ 0.060,
0 ≦ e ≦ 0.040,
α ≧ 0,
β ≧ 0,
Satisfying the relationship 0 ≦ α + β ≦ 0.50,
The soft magnetic alloy has a nanoheterostructure in which initial microcrystals exist in an amorphous state,
The surface of the soft magnetic alloy particles is covered by a coating portion,
The soft magnetic alloy powder, wherein the covering portion contains a compound of at least one element selected from the group consisting of P, Si, Bi and Zn.   The soft magnetic alloy powder according to claim 1, wherein an average particle diameter of the initial microcrystal is 0.3 nm or more and 10 nm or less. Composition formula _{(Fe (1- (α + β} )) X1 α X2 β) (1- (a + b + c + d + e)) M a B b P c Si d C e in soft including a plurality of soft magnetic alloy particles made of a soft magnetic alloy represented by A magnetic alloy powder,
The soft magnetic alloy powder has an average particle diameter (D50) of 0.3 to 100 μm,
X1 is one or more selected from the group consisting of Co and Ni;
X2 is at least one selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O and a rare earth element;
M is one or more selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W and V;
a, b, c, d, e, α and β are
0.020 ≦ a ≦ 0.14,
0.020 <b ≦ 0.20,
0 <c ≦ 0.15,
0 ≦ d ≦ 0.060,
0 ≦ e ≦ 0.040,
α ≧ 0,
β ≧ 0,
Satisfying the relationship 0 ≦ α + β ≦ 0.50,
The soft magnetic alloy has Fe-based nanocrystals,
The surface of the soft magnetic alloy particles is covered by a coating portion,
The soft magnetic alloy powder, wherein the covering portion contains a compound of at least one element selected from the group consisting of P, Si, Bi and Zn. The soft magnetic alloy powder according to claim 3, wherein the average particle diameter of the Fe-based nanocrystal is 5 nm or more and 30 nm or less.   A dust core made of the soft magnetic alloy powder according to claim 1.   A magnetic component comprising the dust core according to claim 5.