JP6773193B2 - Soft magnetic alloy powder, powder magnetic core and magnetic parts - Google Patents

Description

The present invention relates to soft magnetic alloy powders, powder magnetic cores and magnetic parts.

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 wire), which is an electric conductor, is arranged around or inside a magnetic core (core) that exhibits a predetermined magnetic characteristic.

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

By the way, in order to obtain a magnetic core as a powder magnetic core, it is necessary to make such a soft magnetic alloy into a powder and 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, if particles composed of soft magnetic alloys are in contact with each other, a current flowing between the contacting particles (interparticle eddy current) when a voltage is applied to a magnetic component. ), And as a result, there is a problem that the core loss of the dust core becomes large.

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

Japanese Patent No. 3342767 JP-A-2015-1332010

In Patent Document 2, the Fe-based amorphous alloy powder on which the insulating coating layer is formed is mixed with a resin and compression-molded to form a powder magnetic core. If the thickness of the insulating coating layer is increased, the withstand voltage resistance of the dust core is improved, but the filling rate of the magnetic component is lowered, 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 soft magnetic alloy powder on which the insulating coating layer is formed as a whole.

The present invention has been made in view of such an actual situation, and an object of the present invention is to provide a powder magnetic core having good withstand voltage resistance, a magnetic component provided with the powder magnetic core, and a soft magnetic alloy powder suitable for the powder magnetic 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 resistance of the entire powder containing the soft magnetic alloy particles is improved. The invention has been completed.

That is, the aspect of the present invention is
[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 one or more selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O and rare earth elements.
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
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 of 0≤α + β≤0.50,
The soft magnetic alloy has a nanoheterostructure in which the initial microcrystals are present in the amorphous state.
The surface of the soft magnetic alloy particles is covered with a coating,
The coating portion is a soft magnetic alloy powder characterized by containing a compound of one or more elements selected from the group consisting of P, Si, Bi and Zn.

[2] The soft magnetic alloy powder according to [1], wherein the average particle size of the initial microcrystals 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 one or more selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O and rare earth elements.
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
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 of 0≤α + β≤0.50,
The soft magnetic alloy has Fe-based nanocrystals and has
The surface of the soft magnetic alloy particles is covered with a coating,
The coating portion is a soft magnetic alloy powder characterized by containing a compound of one or more elements 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 Fe-based nanocrystals is 5 nm or more and 30 nm or less.

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

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

According to the present invention, it is possible to provide a powder magnetic core having good withstand voltage resistance, a magnetic component provided with the powder magnetic core, and a soft magnetic alloy powder suitable for the powder magnetic 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 the configuration of a powder coating device used for forming a coating portion.

Hereinafter, the present invention will be described in detail in the following order based on the specific embodiments shown in the drawings.
1. 1. Soft magnetic alloy powder 1.1. Soft magnetic alloy 1.1.1. First viewpoint 11.2. Second viewpoint 1.2. Cover 2. Powder magnetic core 3. Magnetic parts 4. Manufacturing method of dust core 4.1. Method for manufacturing 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 contains a plurality of coated particles 1 having a coated portion 10 formed on the surface of the soft magnetic alloy particles 2. When the number ratio of the particles contained in the soft magnetic alloy powder is 100%, the number ratio of the coated particles is preferably 90% or more, and 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 size (D50) of the soft magnetic alloy powder according to the present embodiment may be selected according to the application and the material. In the present embodiment, the average particle size (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 becomes easy to maintain sufficient moldability or predetermined magnetic properties. The method for measuring the average particle size is not particularly limited, but it is preferable to use the laser diffraction / scattering method.

In the present embodiment, the soft magnetic alloy powder may contain only soft magnetic alloy particles of the same material, or may contain soft magnetic alloy particles of different materials. Examples of different materials include cases where the elements constituting the soft magnetic alloy are different, cases where the constituent elements are the same but the composition is different, 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 separately as a soft magnetic alloy according to the first aspect and a soft magnetic alloy according to the 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 the 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 are present in amorphous material. Such a structure is a structure in which a large number of microcrystals are precipitated and dispersed in an amorphous alloy obtained by quenching a molten metal in which a raw material of a soft magnetic alloy is dissolved. Therefore, the average particle size of the initial crystallites is very small. In the present embodiment, the average particle size of the initial microcrystals is preferably 0.3 nm or more and 10 nm or less.

By heat-treating a soft magnetic alloy having such a nanoheterostructure under predetermined conditions, initial microcrystals are grown, and the soft magnetic alloy according to the second aspect described later (soft magnetic having Fe-based nanocrystals). It becomes easy to obtain an 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 in a relatively high concentration.

In the above composition formula, M is one or more elements selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W and V.

Further, 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. The M content (a) is preferably 0.10 or less, more preferably 0.080 or less.

When a is too small, a crystal phase composed of crystals having a particle size larger than 30 nm is likely to be formed in the soft magnetic alloy. When such a crystal phase is generated, Fe-based nanocrystals cannot be precipitated by heat treatment. As a result, the specific resistance of the soft magnetic alloy tends to be low, and the coercive force tends to be high. On the other hand, when a is too large, the saturation magnetization of the powder tends to decrease.

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 further preferably 0.080 or more. The B content (b) is preferably 0.15 or less, and more preferably 0.12 or less.

If b is too small, a crystal phase composed of crystals having a particle size larger than 30 nm is likely to be formed in the soft magnetic alloy. When such a crystal phase is generated, Fe-based nanocrystals cannot be precipitated by heat treatment. As a result, the specific resistance of the soft magnetic alloy tends to be low, and the coercive force tends to be high. On the other hand, when 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 content (c) of P is preferably 0.005 or more, and more preferably 0.010 or more. 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, it tends to be difficult to obtain the above effect. On the other hand, when 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 does not have to contain Si. The Si content (d) is preferably 0.001 or more, and more preferably 0.005 or more. The Si content (d) 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 lowered. 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 does not have to contain C. The C content (e) is preferably 0.001 or more. The C content (e) is preferably 0.035 or less, more preferably 0.030 or less.

When e is within the above range, the coercive force of the soft magnetic alloy tends to decrease particularly easily. 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 Fe content is not particularly limited, but in the present embodiment, the Fe content (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, it becomes difficult to form a crystal phase composed of crystals having a particle size larger than 30 nm. As a result, it tends to be easy to obtain a soft magnetic alloy in which Fe-based nanocrystals are precipitated by heat treatment.

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 this embodiment, α is 0 or more. That is, the soft magnetic alloy does not have to contain X1.

Further, when the number of atoms in the entire composition is 100 at%, the number of atoms in X1 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 this embodiment, β is 0 or more. That is, the soft magnetic alloy does not have to contain X2.

Further, when the number of atoms in the entire composition is 100 at%, the number of atoms in X2 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 Fe is set to half or less of the total number of atoms of Fe in terms of atomic number. 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 contain elements other than the above as unavoidable impurities. For example, elements other than the above may be contained in an amount of 0.1% by weight or less in total with respect to 100% by weight of the soft magnetic alloy.

(1.1.2. Second viewpoint)
The soft magnetic alloy according to the second aspect has the same structure as the soft magnetic alloy according to the first aspect except that its structure is different, and redundant description will be omitted. That is, the description of 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. 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, a large number of Fe-based nanocrystals are precipitated and dispersed in the amorphous material. In the present embodiment, Fe-based nanocrystals are suitably obtained by heat-treating the powder containing the soft magnetic alloy according to the first aspect to grow initial microcrystals.

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

(1.2. Cover)
As shown in FIG. 1, the covering portion 10 is formed so as to cover the surface of the soft magnetic metal particles 2. Further, in the present embodiment, the fact that the surface is covered with a substance means a form in which the substance is in contact with the surface and is fixed so as to cover the contacted portion. Further, the coating portion that covers the soft magnetic alloy particles may cover at least a part of the surface of the particles, but it is preferable that the coating portion covers the entire surface. Further, the covering portion may continuously cover the surface of the particles or may intermittently cover the surface of the particles.

The covering portion 10 is not particularly limited as long as it has a structure capable of insulating 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 adopting the above-mentioned structure of the covering portion, the adhesion to the elements segregated in the amorphous 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. "Contains an oxide of one or more elements selected from the group consisting of P, Si, Bi and Zn as a main component" means the total amount of the elements contained in the covering portion 10 excluding oxygen. When it is set to 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. Further, in the present 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, and for example, a phosphate (P ₂ O ₅ ) -based glass, a bismuth acid salt (Bi ₂ O ₃ ) -based glass, and a 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. In addition, "R" represents 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 series glass and the like are exemplified.

By having such an insulating coating portion, the insulating property of the particles becomes higher, so that the withstand voltage of the powder magnetic core composed of the soft magnetic alloy powder containing the coating particles is improved.

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

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

(2. Powder magnetic core)
The powder magnetic core according to the present embodiment is not particularly limited as long as it is composed of the above-mentioned soft magnetic alloy powder and is formed so as to have a predetermined shape. In the present embodiment, the soft magnetic alloy powder and the resin as a binder are contained, and the soft magnetic alloy particles constituting the soft magnetic alloy powder are fixed to a predetermined shape by being bonded to each other via the resin. Further, the powder magnetic core may be composed 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 embedded inside a dust core having a predetermined shape, or a wire is wound by a predetermined number of turns on the surface of a dust core having a predetermined shape. It may be a magnetic component that is turned. Since the magnetic component according to the present embodiment has good withstand voltage resistance, it is suitable for a power inductor used in a power supply circuit.

(4. Manufacturing method of dust core)
Subsequently, a method for manufacturing the dust core provided in the above magnetic component will be described. First, a method for producing a soft magnetic alloy powder constituting a powder magnetic 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 the same method as the known method for producing the soft magnetic alloy powder. Specifically, it can be produced by using a gas atomizing method, a water atomizing method, a rotating disc method, or the like. Further, the thin band obtained by the single roll method or the like may be mechanically pulverized for production. Among these, it is preferable to use the gas atomizing method from the viewpoint that a soft magnetic alloy powder having desired magnetic properties can be 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 dissolved is obtained. Raw materials (pure metal, etc.) for each metal element contained in the soft magnetic alloy are prepared, weighed so as to have the final composition of the soft magnetic alloy, and the raw materials are dissolved. The method for dissolving the raw material of the metal element is not particularly limited, and for example, a method of evacuating in the chamber of the atomizing apparatus 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 blown onto the supplied molten metal to atomize the molten metal and quench it. Obtain a fine powder. The gas injection temperature, the pressure in the chamber, and the like may be determined according to the conditions under which Fe-based nanocrystals are likely to precipitate in the amorphous substance in the heat treatment described later. Further, the particle size can be adjusted by performing sieve classification, air flow classification, or the like.

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

In the present embodiment, when crystals having a particle size larger than 30 nm are present in the soft magnetic alloy before the heat treatment, it is determined that a crystal phase is present, and crystals having a particle size larger than 30 nm are present. If not, it is judged to be amorphous. Whether or not crystals having a particle size larger than 30 nm are present 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 when it is not amorphous, diffraction spots due to the crystal structure are formed. It is formed.

The presence or absence of the above-mentioned initial microcrystals and the method of observing the average particle size are not particularly limited and may be evaluated by a known method. For example, it can be confirmed by obtaining a bright-field image or a high-resolution image of a sample sliced by ion milling using a transmission electron microscope (TEM). Specifically, the presence or absence of initial microcrystals and the average particle size can be evaluated 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 times. ..

Next, the obtained powder is heat-treated. By performing the heat treatment, while preventing the particles from sintering each other and coarsening the powder, the diffusion of the elements constituting the soft magnetic alloy is promoted, the thermodynamic equilibrium state is reached in a short time, and the soft magnetic The strain and stress existing in the alloy can be removed. As a result, it becomes easy to obtain a soft magnetic alloy in 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 conditions are not particularly limited as long as the Fe-based nanocrystals are likely to precipitate. 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 soft magnetic alloy in which Fe-based nanocrystals are precipitated, that is, a powder containing soft magnetic alloy particles made of the soft magnetic alloy according to the second aspect is obtained.

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

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

In the present embodiment, it can be formed by a coating method using mechanochemicals, a phosphate treatment method, a sol-gel method, or the like. In the coating method using mechanochemicals, for example, the powder coating apparatus 100 shown in FIG. 2 is used. A mixed powder of the soft magnetic alloy powder and the powder coating material of the material (compound of P, Si, Bi, Zn, etc.) constituting the coating portion is put into the container 101 of the powder coating apparatus. By rotating the container 101 after charging, 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, friction is generated, and heat is generated. The generated frictional heat softens the powdery coating material and causes it to adhere to the surface of the soft magnetic alloy particles by a compressive action to form a coating portion.

In the coating method using mechanochemicals, 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, etc., and the mixture of the soft magnetic alloy powder and the mixed powder is controlled. The temperature can be controlled. In the present embodiment, the temperature is preferably 50 ° C. or higher and 150 ° C. or lower. By setting the temperature in such a range, it becomes easy to form the coating portion so as to cover the surface of the soft magnetic alloy particles.

(4.2. Manufacturing method of dust core)
The powder magnetic core is manufactured by using the above-mentioned soft magnetic alloy powder. The specific production method is not particularly limited, and a known method can be adopted. First, the soft magnetic alloy powder containing the soft magnetic alloy particles forming the coating portion and a known resin as a binder are mixed to obtain a mixture. Further, if necessary, the obtained mixture may be used as a granulated powder. Then, the mixture or granulated powder is filled in a mold and compression molded to obtain a molded product having the shape of a dust core to be produced. By heat-treating the obtained molded product 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 can be obtained. A magnetic component such as an inductor can be obtained by winding a wire around the obtained dust core a predetermined number of times.

Further, even if the above mixture or granulated powder and an air-core coil formed by winding a wire a predetermined number of times are filled in a mold and compression-molded to obtain a molded body in which the coil is embedded inside. Good. By heat-treating the obtained molded product, a dust core having a predetermined shape in which a coil is embedded can be obtained. Since a coil is embedded in such a dust core, it functions as a magnetic component such as an inductor.

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

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

(Experimental Examples 1-45)
First, a raw material metal for a soft magnetic alloy was prepared. The prepared raw material metal was weighed so as to have the composition shown in Table 1 and housed in a crucible arranged in the atomizing apparatus. Subsequently, after vacuuming the inside of 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 molten metal (molten metal) at 1250 ° C. 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 gas was blown onto the supplied molten metal to obtain a powder. The gas injection temperature was 1250 ° C., and the pressure in the chamber was 1 hPa. The average particle size (D50) of the obtained powder was 20 μm.

X-ray diffraction measurement was performed on the obtained powder, and the presence or absence of crystals having a particle size larger than 30 nm was confirmed. Then, when there is no crystal having a particle size larger than 30 nm, it is determined that the soft magnetic alloy constituting the powder is composed of an amorphous phase, and when a crystal having a particle size larger than 30 nm exists, it is soft. It was determined that the magnetic alloy consisted of a crystalline phase. The results are shown in Table 1.

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. The powder after the heat treatment was subjected to X-ray diffraction measurement and observation by TEM to evaluate the presence or absence of Fe-based nanocrystals. The results are shown in Table 1. 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 in all the samples of the examples in which the Fe-based nanocrystals were present.

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

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

The powdered glass was a phosphate-based glass having a composition of P ₂ O _5- ZnO-R ₂ O-Al ₂ O ₃ . The specific composition was 50 wt% for P ₂ O ₅ , 12 wt% for Zn O, 20 wt% for R ₂ O, 6 wt% for Al ₂ O ₃ , and the balance was a subcomponent.

In addition, the present inventors have a glass having a composition in which P ₂ O ₅ is 60 wt%, Zn O is 20 wt%, R ₂ O is 10 wt%, Al ₂ O ₃ is 5 wt%, and the balance is a subcomponent. The same experiment was performed on glass having a composition in which ₂ O ₅ is 60 wt%, Zn O is 20 wt%, R ₂ O is 10 wt%, Al ₂ O ₃ is 5 wt%, and the balance is a subcomponent, which will be described later. We have confirmed that the same results as the results can be obtained.

Next, the soft magnetic alloy powder on which the coating portion was formed was solidified, and the resistivity of the powder was evaluated. The resistivity of the powder was measured using a powder resistance measuring device in a state where a pressure of 0.6 t / cm ² was applied. 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 less than or equal to were marked with "x". The results are shown in Table 1.

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

A voltage was applied above and below the obtained powder magnetic core sample using a source meter, and the voltage value at which a current of 1 mA flowed was taken as the withstand voltage. In this example, a sample having a withstand voltage of 100 V / mm or more was considered good. The results are shown in Table 1.

From Table 1, it was confirmed that when the content of each component was within the above-mentioned range and the nanoheterostructure or Fe-based nanocrystals were present, the characteristics of the powder and the dust core were good.

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

(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 used as the element shown in Table 2. The same evaluation as in 1, 4 and 8 was performed. Further, using the obtained powder, a dust core was prepared 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. The results are shown in Table 2.

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 73-126)
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 the elements and contents shown in Table 3. , The same evaluation as in Experimental Example 1 was performed. Further, using the obtained powder, a dust core was prepared in the same manner as in Experimental Example 1, and the same evaluation as in Experimental Example 1 was performed. The results are shown in Table 3.

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

(Experimental Examples 127-147)
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 portion formed by using the coating material was set to the value shown in Table 4, but the softness was the same as that of Experimental Example 1. A magnetic alloy powder was prepared and evaluated in the same manner as in Experimental Example 1. Further, using the obtained powder, a dust core was prepared in the same manner as in Experimental Example 1, and the same evaluation as in Experimental Example 1 was performed. The results are shown in Table 4. No covering portion was formed on the sample of Experimental Example 127.

Further, in this embodiment, in the Bi ₂ O _3- ZnO-B ₂ O _3- SiO ₂ powder glass as the bismuthate-based glass, Bi ₂ O ₃ is 80 wt%, Zn O is 10 wt%, and B ₂ O _{3 is used.} Was 5 wt% and SiO ₂ was 5 wt%. Similar experiments have been conducted on glasses having other compositions as bismuthate-based glasses, and it has been confirmed that the same results as those described later can be obtained.

Further, in this embodiment, in the BaO-ZnO-B ₂ O _3- SiO _2- Al ₂ O ₃ powder glass as the borosilicate glass, BaO is 8 wt%, ZnO is 23 wt%, and B ₂ O ₃ is. 19 wt%, SiO ₂ was 16 wt%, Al ₂ O ₃ was 6 wt%, and the balance was a subcomponent. Similar experiments have been conducted on glasses having other compositions as borosilicate-based glasses, and it has been confirmed that the same results as those described later can be obtained.

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

(Experimental Examples 148 to 161)
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 temperature of the molten metal at the time of atomization and the heat treatment conditions of the powder obtained by atomization were set as the conditions shown in Table 5, and the experiment was conducted. The same evaluation as in Example 1 was performed. Further, using the obtained powder, a dust core was prepared in the same manner as in Experimental Example 1, and the same evaluation as in Experimental Example 1 was performed. The results are shown in Table 5.

From Table 5, for the powder having a nanoheterostructure having initial microcrystals and the powder having Fe group nanocrystals after heat treatment, the resistance of the powder does not depend on the average particle size of the initial microcrystals and the average particle size of Fe group nanocrystals. It was confirmed that the rate and the withstand voltage of the dust core were good.

1 ... Covered particles 10 ... Covered part 2 ... Soft magnetic alloy particles

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 It is a magnetic alloy powder
The average particle size (D50) of the soft magnetic alloy powder is 0.3 to 100 μm.
X1 is one or more selected from the group consisting of Co and Ni.
X2 is one or more selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O and rare earth elements.
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
0.020 ≤ a ≤ 0.14,
0.020 <b ≤ 0.20,
0 <c ≦ 0.15,
0.001 ≤ d ≤ 0.060 ,
0 ≦ e ≦ 0.040,
α ≧ 0,
β ≧ 0,
Satisfying the relationship of 0≤α + β≤0.50,
The soft magnetic alloy has a nanoheterostructure in which initial microcrystals are present in amorphous material.
The surface of the soft magnetic alloy particles is covered with a coating portion, and the surface thereof is covered with a coating portion.
The coating contains a compound of one or more elements selected from the group consisting of P, Si, Bi and Zn.
Soft magnetic alloy powder, characterized in that 0.6 t / cm ² resistivity while applying a pressure of at 10 ⁴ [Omega] cm or more. The soft magnetic alloy powder according to claim 1, wherein the average particle size of the initial microcrystals 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 It is a magnetic alloy powder
The average particle size (D50) of the soft magnetic alloy powder is 0.3 to 100 μm.
X1 is one or more selected from the group consisting of Co and Ni.
X2 is one or more selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O and rare earth elements.
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
0.020 ≤ a ≤ 0.14,
0.020 <b ≤ 0.20,
0 <c ≦ 0.15,
0.001 ≤ d ≤ 0.060 ,
0 ≦ e ≦ 0.040,
α ≧ 0,
β ≧ 0,
Satisfying the relationship of 0≤α + β≤0.50,
The soft magnetic alloy has Fe-based nanocrystals and has
The surface of the soft magnetic alloy particles is covered with a coating portion, and the surface thereof is covered with a coating portion.
The coating contains a compound of one or more elements selected from the group consisting of P, Si, Bi and Zn.
Soft magnetic alloy powder, characterized in that 0.6 t / cm ² resistivity while applying a pressure of at 10 ⁴ [Omega] cm or more. The soft magnetic alloy powder according to claim 3, wherein the average particle size of the Fe-based nanocrystals is 5 nm or more and 30 nm or less. A powder magnetic core composed of the soft magnetic alloy powder according to any one of claims 1 to 4. The magnetic component having the dust core according to claim 5.