JP2022068108A - Alloy powder, manufacturing method for alloy powder, soft magnetic material, dust core and manufacturing method for dust core - Google Patents

Abstract

To provide Fe-Ni-based alloy powder with higher permeability.SOLUTION: Provided is alloy powder containing Fe, Ni and B, where a content of B is 0.04 to 1.5 mass% and the spheroidicity is 0.80 or higher.SELECTED DRAWING: None

Description

The present invention relates to an alloy powder having a predetermined metal composition, a method for producing the alloy powder, and related techniques thereof.

In recent years, the operating frequency of electronic devices has been increasing along with the increasing operating speed and needs for improving responsiveness of electronic devices. Under such circumstances, there have been cases where electrical steel sheets and ferrites, which are soft magnetic materials widely used in the past, cannot be sufficiently dealt with.

In addition, there is a demand for miniaturization of equipment, and a powder magnetic core manufactured by mixing soft magnetic powder with a binder or the like as necessary and press-molding is attracting attention. This is because the press molding using the soft magnetic powder has a high degree of freedom in shape including the size, and the powder magnetic core can be freely designed. The main characteristics required for soft magnetic powder are coercive force and magnetic permeability. All of these affect the hysteresis loss that constitutes the magnetic loss, and the lower the coercive force and the higher the magnetic permeability, the smaller the hysteresis loss.

Examples of the soft magnetic powder include Fe (iron) -Ni (nickel) alloy powder (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2018-178254

An object of the present invention is to provide a Fe—Ni alloy powder having a higher magnetic permeability.

As a result of diligent studies to solve the above problems, the present inventors have obtained a Fe—Ni alloy powder having a high magnetic permeability by containing a specific amount of B (boron) in the Fe—Ni alloy powder. The present invention was completed.

That is, the present invention is as follows.
[1] An alloy powder containing Fe, Ni, and B, having a B content of 0.04 to 1.5% by mass and a sphericity of 0.80 or more.

[2] The alloy powder according to [1], wherein the content of B is 0.04 to 1.0% by mass.

[3] The alloy powder according to [1] or [2], wherein the cumulative 50% particle diameter (D50) on a volume basis measured by a laser diffraction type particle size distribution measuring device is 0.1 to 15 μm.

[4] The alloy powder according to any one of [1] to [3], wherein the content of B is 0.05 to 0.8% by mass.

[5] The alloy powder according to any one of [1] to [4], wherein the total content of Fe and Ni is 96% by mass or more.

[6] The alloy powder according to any one of [1] to [5], wherein the total content of Fe, Ni and B is 96.05% by mass or more.

[7] Fe content is 18 to 58% by mass, Ni content is 40 to 80% by mass, and B content is 0.13 to 0.6% by mass, [1] to The alloy powder according to any one of [6].

[8] Fe content is 6 to 38% by mass, Ni content is 60 to 92% by mass, and B content is 0.04 to 0.30% by mass, [1] to The alloy powder according to any one of [6].

[9] Fe content is 6 to 38% by mass, Ni content is 60 to 92% by mass, and B content is 0.04 to 0.11% by mass, [1] to The alloy powder according to any one of [5].

[10] A molten metal containing Fe, Ni, and B, wherein the content of B in the molten metal is 0.04 to 1.7% by mass is prepared, and the molten metal is dropped while being dropped. A method for producing an alloy powder, which obtains an alloy powder by crushing and solidifying the molten metal by spraying a fluid on the flow of the molten metal.

[11] The method for producing an alloy powder according to [10], wherein the content of B in the molten metal is 0.04 to 1.0% by mass.

[12] The method for producing an alloy powder according to [10], wherein the content of B in the molten metal is 0.05 to 0.8% by mass.

[13] The method for producing an alloy powder according to any one of [10] to [12], wherein the total content of Fe, Ni and B in the molten metal is 96.05% by mass or more.

[14] A soft magnetic material containing the alloy powder according to any one of [1] to [8] and a binder.

[15] A powder magnetic core containing the alloy powder according to any one of [1] to [8].

[16] The alloy powder according to any one of [1] to [8] or the soft magnetic material according to [14] is molded into a predetermined shape, and the obtained molded product is heated to form a dust core. Obtaining, a method for manufacturing a powder magnetic core.

According to the present invention, an Fe—Ni alloy powder having excellent magnetic permeability is provided.

Hereinafter, embodiments of the alloy powder and the like of the present invention will be described.
[Alloy powder]
<Composition>
An embodiment of the alloy powder of the present invention is a soft magnetic alloy powder containing Fe (iron), Ni (nickel) and B (boron) and having a B content of 0.04 to 1.5% by mass. Is. Hereinafter, each element constituting this powder will be described.

(Fe)
Fe is an element that contributes to the magnetic properties and mechanical properties of the alloy powder. The content of Fe in the alloy powder is preferably 5 to 90% by mass, more preferably 10 to 85% by mass, from the viewpoint of magnetic properties and mechanical properties. From the viewpoint of achieving high magnetic permeability and low coercive force, the Fe content is preferably 6 to 38% by mass, more preferably 8 to 18% by mass. Further, from the viewpoint of achieving high saturation magnetization for applications in which DC superimposition characteristics are important, the Fe content is preferably 18 to 58% by mass, more preferably 30 to 57% by mass.

(Ni)
Ni is an element that contributes to the magnetic properties and corrosion resistance properties of the embodiment of the alloy powder of the present invention. The content of Ni in the alloy powder is preferably 8 to 93% by mass, more preferably 13 to 78% by mass, from the viewpoint of magnetic properties and corrosion resistance. From the viewpoint of achieving high magnetic permeability and low coercive force, the Ni content is preferably 60 to 92% by mass, more preferably 70 to 92% by mass, and even more preferably 80 to 90% by mass. .. Further, from the viewpoint of achieving high saturation magnetization for applications in which DC superimposition characteristics are important, the Ni content is preferably 40 to 80% by mass, more preferably 42 to 68% by mass.

(B)
B is an element that contributes to high magnetic permeability by increasing the sphericity of the embodiment of the alloy powder of the present invention, and the content in the alloy powder is 0.04 to 1.5% by mass from the viewpoint of increasing magnetic permeability. Is set to. From the viewpoint of increasing the magnetic permeability, the content is preferably 0.04 to 1.0% by mass, more preferably 0.05 to 0.8% by mass. From the viewpoint of achieving high magnetic permeability and low coercive force, the content of B is preferably 0.04 to 0.11% by mass, more preferably 0.05 to 0.09% by mass. Further, from the viewpoint of achieving high saturation magnetization for applications where DC superimposition characteristics are important, the content of B is preferably 0.13 to 0.6% by mass, preferably 0.13 to 0.4% by mass. % Is more preferable.

(Total content of Fe and Ni)
In the embodiment of the alloy powder of the present invention, the total content of Fe and Ni is preferably 96% by mass or more, more preferably 97, from the viewpoint of magnetic properties, mechanical properties and corrosion resistance properties of the alloy powder. It is ~ 99.9% by mass, more preferably 98-99.8% by mass.

(Total content of Fe, Ni and B)
In the embodiment of the alloy powder of the present invention, the total content of Fe, Ni and B is preferably 96.05% by mass or more from the viewpoint of the magnetic property, mechanical property and corrosion resistance property of the alloy powder. It is more preferably 97.05 to 99.95% by mass, and even more preferably 98.05 to 99.85% by mass.

Regarding the content of each element, the Fe content is 18 to 58% by mass, the Ni content is 40 to 80% by mass, and the B content is 0.13 to 0.6% by mass. Is preferable. By setting such a content, it is possible to maintain high mechanical properties and corrosion resistance properties, and to realize high magnetic permeability and low coercive force for magnetic properties, while further increasing saturation magnetization.
On the other hand, from the viewpoint of lowering the coercive force and increasing the magnetic permeability among the magnetic properties, the Fe content is 6 to 38% by mass, the Ni content is 60 to 92% by mass, and B. The content of is preferably 0.04 to 0.30% by mass. Further, it is more preferable that the Fe content is 6 to 38% by mass, the Ni content is 60 to 92% by mass, and the B content is 0.04 to 0.11% by mass. By setting such a content, it is possible to maintain high mechanical properties and corrosion resistance properties, and to realize high magnetic permeability and high saturation magnetization for magnetic properties, while lowering the coercive force.

(O (oxygen))
The oxygen content (oxygen content) in the embodiment of the alloy powder of the present invention is preferably 0.75% by mass or less from the viewpoint of the magnetic permeability of the alloy powder (the oxygen content is usually 0.05% by mass or more). Is). From the same viewpoint, the amount of oxygen is more preferably 0.06 to 0.60% by mass.

Since the amount of oxygen increases as the particle size of the powder becomes smaller, the amount of oxygen (O) and the volume standard measured by the laser diffraction type particle size distribution measuring device of the alloy powder are used to correct the fluctuation of the oxygen content due to the particle size. The product (O × D50 (mass% · μm)) with the cumulative 50% particle size (D50) of the above may be adopted. The product (O × D50 (mass% · μm)) is preferably 5 (mass% · μm) or less, and 0.2 to 2 (mass% · μm), from the viewpoint of achieving high magnetic permeability of the alloy powder. It is more preferably μm).

(C (carbon))
The carbon content (carbon content) in the embodiment of the alloy powder of the present invention is preferably 0.003 to 0.20% by mass, and more preferably 0. It is 006 to 0.05% by mass.

(Other elements)
The embodiment of the alloy powder of the present invention may contain other elements in addition to Fe, Ni, B, O and C described above as long as the effects of the present invention are exhibited. Examples are Na (sodium), K (potassium), Mg (magnesium), Ca (calcium), St (strontium), Ba (barium), Ti (titanium), Zr (zyrosine), V (vanadium), Cr (chromium), Pd (palladium), Mo (molybdenum), Mn (manganesium), Co (cobalt), Cu (copper), Al (aluminum), Si (silicon), Sn (tin), N (nitrogen), Examples thereof include P (phosphorus), S (sulfur) and Cl (chlorine). These may be present in the alloy powder as unavoidable impurities, or may be intentionally added in a small amount for the purpose of exerting some function. The total content of these elements in the alloy powder is preferably 1% by mass or less, more preferably 10 to 5000 ppm.

<Sphericity>
An embodiment of the alloy powder of the present invention contains a predetermined amount of B, and is typically produced by an atomizing method described later. Due to the action of a predetermined amount of B, the sphericity of the alloy powder is increased, and specifically, the sphericity is 0.80 or more. When the degree of sphericity is high as described above, the powder is satisfactorily filled when the magnetic component such as a dust core is formed, the contact area between the powders becomes large, and good magnetic characteristics (high magnetic permeability) are exhibited. If the sphericity is too high and approaches a true sphere, the contact area between the powders may be smaller, so the sphericity of the alloy powder is preferably 0.81 to 0.92.

The method for measuring the sphericity is as follows.
The alloy powder, epoxy resin and curing agent are mixed and vacuum defoamed. The vacuum defoamed mixture is placed on a sample table and cured at 120 ° C. A sample with a particle cross section is prepared by polishing the cured sample with a cross section polisher (IB-19530CP, manufactured by JEOL Ltd.). Using FE-SEM (JSM-7200F, manufactured by JEOL Ltd.), the obtained particle cross section is photographed at a magnification of 1,000 to 10,000 times so that 10 to 20 particles are photographed in one field of view. .. Using image analysis type particle size distribution measurement software (Mac-View, Mountech Co., Ltd.), the entire particle shape of multiple images taken is taken, and the major axis is D50, which is an alloy powder that does not stick to other particles. On the other hand, a total of 1000 particles having a size in the range of ± 1 μm are selected. The major axis is a line segment connecting two points on the contour of the particle, and is the length of the line segment having the maximum length among the line segments that do not pass outside the contour. Use the point tool or the simple tool to select particles. The area and peripheral length of each selected particle are obtained by the software, the circularity coefficient of each particle is obtained from these, and the average value thereof is taken as the sphericity in the present invention. The circularity coefficient is calculated by the following formula.

Circularity coefficient = 4 × π × S / L ²
S: Particle area L: Perimeter of the particle

<Average particle size (D50)>
The cumulative 50% particle diameter (D50) based on the volume measured by the laser diffraction type particle size distribution measuring device according to the embodiment of the alloy powder of the present invention is not particularly limited, but the eddy current loss is reduced by using fine particles. From the viewpoint, it is preferably 0.1 to 15 μm, more preferably 0.5 to 8 μm, and even more preferably 1.5 to 5 μm.

<BET specific surface area>
The specific surface area (BET specific surface area) measured by the BET one-point method according to the embodiment of the alloy powder of the present invention is preferable from the viewpoint of suppressing the generation of oxides on the particle surface of the powder and exhibiting good magnetic properties. Is 0.2 to 2 m ² / g, more preferably 0.3 to 1 m ² / g.

<Tap density>
The tap density of the embodiment of the alloy powder of the present invention is preferably 2.0 to 7.5 g / cm ³ and more preferably 2 from the viewpoint of increasing the packing density of the powder and exhibiting good magnetic properties. It is 0.8 to 6.5 g / cm ³ .

[Manufacturing method of alloy powder]
The alloy powder of the present invention described above can be produced by the method for producing an alloy powder of the present invention. Hereinafter, embodiments of the manufacturing method will be described.

<Preparation of molten metal (melt preparation process)>
In the form of the method for producing an alloy powder of the present invention, a molten metal containing Fe, Ni and B is prepared. The content of B in the molten metal is preferably 0.04 to 1.7% by mass from the viewpoint of realizing the above composition in the alloy powder. The molten metal can be prepared by heating and melting the metal as a raw material to a temperature equal to or higher than the melting point of the one having the highest melting point. The content of each element in the molten metal shall be the ratio of the raw materials for the molten metal.

From the viewpoint of the magnetic permeability of the obtained alloy powder, the content of B in the molten metal is preferably 0.04 to 1.1% by mass, more preferably 0.04 to 1.0% by mass, and further. , 0.05 to 0.9% by mass, more preferably 0.05 to 0.8% by mass. The content of Fe in the molten metal is preferably 5 to 90% by mass, more preferably 10 to 85% by mass, from the viewpoint of the magnetic properties and mechanical properties of the alloy powder. The content of Ni in the molten metal is preferably 8 to 93% by mass, more preferably 13 to 78% by mass, from the viewpoint of magnetic properties and corrosion resistance. From the viewpoint of achieving high magnetic permeability and low coercive force, the content of Ni in the molten metal is preferably 60 to 92% by mass, more preferably 70 to 92% by mass, and 80 to 90% by mass. Is even more preferable. Further, from the viewpoint of achieving high saturation magnetization for applications in which DC superimposition characteristics are important, the content of Ni in the molten metal is preferably 40 to 80% by mass, preferably 42 to 68% by mass. More preferred.

From the viewpoint of achieving high magnetic permeability and low coercive force of the alloy powder, the Fe content in the molten metal is 6 to 38% by mass, the Ni content is 60 to 92% by mass, and the B content is 0.04. The content of Fe in the molten metal is preferably 8 to 18% by mass, the content of Ni is 80 to 90% by mass, and the content of B is 0.05 to 0.1% by mass. % Is more preferable.
Alternatively, from the viewpoint of achieving high magnetic permeability and low coercive force of the alloy powder, the Fe content in the molten metal is 6 to 38% by mass, the Ni content is 60 to 92% by mass, and B. The content is preferably 0.04 to 0.60% by mass. Further, the Fe content in the molten metal is 6 to 38% by mass, the Ni content is 60 to 92% by mass, and the B content is 0.04 to 0.55% by mass. preferable.

Further, when the alloy powder is used in an application in which the DC superimposition characteristic is important, the Fe content in the molten metal is 18 to 58% by mass and the Ni content is 40 to 40 to achieve from the viewpoint of achieving high saturation magnetization. It is preferable that the content of B is 0.08 to 0.6% by mass at 80% by mass, and the content of Fe in the molten metal is 30 to 57% by mass and the content of Ni is 42 to 68% by mass. The content of is more preferably 0.1 to 0.4% by mass.

The total content of Fe and Ni in the molten metal is preferably 96% by mass or more, more preferably 97 to 99.9% by mass, still more preferably, from the viewpoint of magnetic properties, mechanical properties and corrosion resistance properties. Is 98-99.8% by mass. The total content of Fe, Ni and B in the molten metal is preferably 96.05% by mass or more, more preferably 97.05 to 99.95% by mass, from the viewpoint of magnetic properties, mechanical properties and corrosion resistance properties. %, More preferably 98.05 to 99.85% by mass.

When preparing the molten metal, from the viewpoint of suppressing the mixing of oxygen into the molten metal, prepare the molten metal in an atmosphere of a non-oxidizing gas (an inert gas such as He, Ar or N ₂ or a reducing gas such as H ₂ or CO). It is preferable to do so.

<Fluid spraying (atomization process)>
By dropping the prepared molten metal from, for example, a hot water nozzle of a furnace and blowing a fluid on the flowing molten metal, the molten metal is crushed and solidified to obtain an alloy powder containing Fe, Ni and B.

Examples of the fluid to be blown on the flowing molten metal include water and a gas having a temperature lower than the melting point of the molten metal. The gas needs to be inert to the molten metal. Water is preferable as the fluid from the viewpoint of obtaining an alloy powder of fine particles.

The temperature of the molten metal when spraying the fluid is 50 to 800 ° C. from the melting point of the molten metal from the viewpoint of lowering the viscosity and increasing the crushing force by the fluid to obtain fine alloy powder, and from the viewpoint of the burden on the furnace and the heat cost. It is preferably high, and more preferably 100 to 700 ° C.

The fluid may be sprayed in an atmospheric atmosphere, but may be performed in a non-oxidizing gas atmosphere in order to suppress the oxidation of the molten metal and the alloy powder formed. Examples of the non-oxidizing gas atmosphere include an inert gas such as He, Ar and N ₂ , and a reducing gas such as H ₂ and CO. In order to obtain an alloy powder having a small amount of oxygen and a high magnetic permeability, it is preferable to lower the oxygen concentration in the atmosphere, and preferably a getter or the like may be used to lower the oxygen concentration. The oxygen concentration in the atmosphere when the fluid is sprayed is preferably 1 ppm or less, more preferably 0.1 ppm or less.

<Other processes>
In the embodiment of the method for producing an alloy powder of the present invention, the following optional steps may be carried out on the alloy powder obtained by spraying the fluid described above.

(Solid-liquid separation process)
When the fluid is a liquid such as water, a slurry in which the alloy powder is dispersed in the liquid is obtained. The alloy powder is recovered by solid-liquid separation of this slurry. As a method for solid-liquid separation, a conventionally known method can be adopted without particular limitation, and the slurry may be pressure-filtered using, for example, a filter press or the like. The recovered alloy powder may be washed with water or the like.

(Drying process)
The alloy powder obtained in the solid-liquid separation step may be dried. Drying may be carried out at room temperature (25 ° C.) or at a high temperature (40 to 120 ° C.) from the viewpoint of improving the drying speed. Further, the drying may be carried out under atmospheric pressure, but from the viewpoint of improving the drying speed, drying may be carried out in a reduced pressure environment of −0.05 MPa or less with respect to atmospheric pressure. Drying may be carried out in a vacuum environment (-0.095 MPa or less).

(Crushing process, classification process)
The alloy powder may be crushed or classified to adjust its particle size distribution.

[Soft magnetic material]
The embodiment of the alloy powder of the present invention described above exhibits high magnetic permeability as described above. From such characteristics, the embodiment of the alloy powder of the present invention can be suitably applied to a soft magnetic material. The alloy powder itself can be used as a soft magnetic material, or it can be a soft magnetic material mixed with a binder. In the latter case, for example, an alloy powder is mixed with a binder (insulating resin and / or an inorganic binder) and granulated to obtain a granular composite powder (soft magnetic material). The content of the alloy powder in this soft magnetic material is preferably 80 to 99.9% by mass from the viewpoint of achieving good magnetic properties. From the same viewpoint, the content of the binder in the soft magnetic material is preferably 0.1 to 20% by mass.

Specific examples of the insulating resin include (meth) acrylic resin, silicone resin, epoxy resin, phenol resin, urea resin, and melamine resin. Specific examples of the inorganic binder include a silica binder and an alumina binder. Further, the soft magnetic material (both in the case of a simple substance of alloy powder and in the case of a mixture of powder and binder) may contain other components such as wax and lubricant, if necessary.

<Powder magnetic core>
By molding the soft magnetic material described above into a predetermined shape, heating and pressurizing the material, a powder magnetic core including the embodiment of the alloy powder of the present invention can be produced. More specifically, a powder magnetic core is obtained by placing a soft magnetic material in a mold having a predetermined shape and heating while pressurizing.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
[Example 1]
In a tundish furnace, 47.5 kg of electrolytic iron (purity: 99.95 mass% or more, manufactured by Toho Zinc Co., Ltd., Atmilon MP-30-25P) and electric nickel (purity: 99 mass% or more, Sumitomo Metal Mining Co., Ltd.) Made by heating 50 kg of electric nickel L) and 1.0 kg of ferroboron (boron ratio: 20% by mass, iron ratio: 79% by mass, manufactured by Shin Nihon Denko Co., Ltd., S11) to 1700 ° C in a nitrogen atmosphere to dissolve the molten metal. ^Tandish under a nitrogen atmosphere (the oxygen concentration in the atmosphere was measured using a zirconia type oxygen meter (ECOAZ TB-II F-S manufactured by Daiichi Thermal Research Co., Ltd.) and found to be 10-15 ppm). While dropping from the bottom of the furnace, high-pressure water (pH 12) was sprayed at a water pressure of 200 MPa and a water volume of 160 L / min to pulverize and solidify.

As a result, a slurry in which FeNiB alloy powder is dispersed in water is obtained, which is subjected to a filter press for solid-liquid separation, and the obtained solid matter is washed with water and dried at 80 ° C. in a vacuum atmosphere to obtain FeNiB alloy powder 1. Obtained.

[Example 2]
FeNiB alloy powder 2 was produced in the same manner as in Example 1 except that the amount of electrolytic iron used was changed to 13.5 kg, the amount of electric nickel used was changed to 85.0 kg, and the amount of ferroboron used was changed to 0.5 kg. bottom.

[Example 3]
FeNiB alloy powder 3 was produced in the same manner as in Example 1 except that the amount of electrolytic iron used was changed to 62.5 kg, the amount of electric nickel used was changed to 36.0 kg, and the amount of ferroboron used was changed to 0.5 kg. bottom.

[Example 4]
FeNiB alloy powder 4 was produced in the same manner as in Example 1 except that the amount of electrolytic iron used was changed to 48.5 kg, the amount of electric nickel used was changed to 50 kg, and the amount of ferroboron used was changed to 0.5 kg.

[Example 5]
FeNiB alloy powder 5 was produced in the same manner as in Example 1 except that the amount of electrolytic iron used was changed to 46.0 kg, the amount of electric nickel used was changed to 50.0 kg, and the amount of ferroboron used was changed to 5 kg.

[Example 6]
FeNiB alloy powder 6 in the same manner as in Example 1 except that the amount of electrolytic iron used was changed to 17.0 kg, the amount of electric nickel used was changed to 79.0 kg, the amount of ferroboron used was changed to 2 kg, and the water pressure was changed to 150 MPa. Manufactured.

[Comparative Example 1]
The FeNi alloy powder 7 was produced in the same manner as in Example 1 except that the amount of electrolytic iron used was changed to 50.0 kg, the amount of electric nickel used was changed to 50.0 kg, and ferroboron was not used.

[Comparative Example 2]
FeNiB alloy powder 8 was produced in the same manner as in Example 1 except that the amount of electrolytic iron used was changed to 48.5 kg, the amount of electric nickel used was changed to 50.0 kg, and the amount of ferroboron used was changed to 11 kg.

Measurement of BET specific surface area, tap density, composition (including oxygen content and carbon content), particle size distribution, sphericity, magnetic properties and compression density changes of FeNiB alloy powders 1 to 8 and FeNi alloy powders obtained as described above. Was done. Specifically, it is as follows.

[BET specific surface area]
For the BET specific surface area, a BET specific surface area measuring instrument (Macsorb manufactured by Mountech Co., Ltd.) was used to flow nitrogen gas into the measuring instrument at 105 ° C. for 20 minutes to remove deposits on the sample surface, and then nitrogen and helium. The measurement was carried out by the BET 1-point method while flowing a mixed gas (N ₂ : 30% by volume, He: 70% by volume).

[Tap Density]
The tap density (TAP) is the same as the method described in JP-A-2007-263860, in which the sample powder is filled in a bottomed cylindrical die having an inner diameter of 6 mm and a height of 11.9 mm up to 80% of the volume. A sample powder layer is formed, a pressure of 0.160 N / m ² is uniformly applied to the upper surface of the sample powder layer, and the sample powder layer is compressed with this pressure until the sample powder is no longer densely packed. The height of the sample powder layer was measured, and the density of the sample powder was obtained from the measured value of the height of the sample powder layer and the weight of the filled sample powder, and this was defined as the tap density of the sample powder.

[composition]
The composition of the sample powder was measured as follows.

(Ni)
Analysis was performed by an inductively coupled plasma (ICP) emission spectrophotometer (720 ICP-OES manufactured by Agilent Technologies, Inc.).

(B)
Analysis was performed by an inductively coupled plasma (ICP) emission spectroscopic analyzer (SPS3520V manufactured by Hitachi High-Tech Science Co., Ltd.).

(Amount of oxygen)
The amount of oxygen was measured by an oxygen / nitrogen / hydrogen analyzer (EMGA-920 manufactured by HORIBA, Ltd.).

(Carbon content)
The amount of carbon was measured by a carbon / sulfur analyzer (EMIA-920V2 manufactured by HORIBA, Ltd.).

[Particle size distribution]
For the particle size distribution, use a laser diffraction type particle size distribution measuring device (SIMPATEC's Heros particle size distribution measuring device (HELOS & RODOS (air flow type dispersion module))), and use nitrogen gas to measure the volume at a dispersion pressure of 5 bar. The standard particle size distribution was obtained.

[Sphericity]
The obtained sample powder, epoxy resin and curing agent were mixed and vacuum defoamed. The vacuum defoamed mixture was placed on a sample table and cured at 120 ° C. The cured sample was polished using a cross section polisher (IB-19530CP, manufactured by JEOL Ltd.) to prepare a sample having a particle cross section. The obtained particle cross section was photographed by FE-SEM (JSM-7200F, manufactured by JEOL Ltd.) at a magnification of 10,000 times so that 10 to 20 particles were photographed in one field of view. Using image analysis type particle size distribution measurement software (Mac-View, Mountech Co., Ltd.), the entire particle shape of multiple images taken is taken, and the major axis is D50 of the sample powder, which is not attached to other particles. On the other hand, a total of 1000 particles having a size within the range of ± 1 μm were selected. A point tool was used to select the particles. The area and perimeter of each selected particle were obtained by the software, the circularity coefficient of each particle was obtained from these, and the average value was taken as the sphericity. The circularity coefficient is calculated by the following formula.

Circularity coefficient = 4 × π × S / L ²
S: Particle area L: Perimeter of the particle

[Measurement of magnetic properties (permeability, coercive force, and saturation magnetization)]
Weigh the sample powder and bisphenol F type epoxy resin (manufactured by Tesk Co., Ltd .; one-component epoxy resin B-1106) at a mass ratio of 97: 3, and use a vacuum stirring / defoaming mixer (manufactured by EME; V-mini300). These were kneaded using the paste to obtain a paste in which the test powder was dispersed in the epoxy resin. This paste was dried on a hot plate at 30 ° C. for 2 hours to form a complex of a sample powder and a resin, and then granulated into a powder to obtain a complex powder. 0.2 g of this complex powder is placed in a donut-shaped container, and a load of 9800 N (1 Ton) is applied by a hand press to obtain a toroidal molded body having an outer diameter of 7 mm, an inner diameter of 3 mm, and a thickness of 1.48 mm. Obtained. For this molded product, the real part μ'of the complex relative permeability at 10 MHz was measured using an RF impedance / material analyzer (manufactured by Agilent Technologies; E4991A) and a test fixture (manufactured by Agilent Technologies; 16454A). .. Further, the weight (g) of the toroidal-shaped molded body was measured, and the density of the molded body was calculated from this and the inner diameter (mm), outer diameter (mm) and thickness (mm) of the molded body.

In addition, using a high-sensitivity vibration sample magnetometer (manufactured by Toei Kogyo Co., Ltd .: VSM-P7-15 type), applied magnetic field (10 kOe), M measurement range (50 emu), step bit 100 bits, time constant 0.03 sec. , The magnetic properties of the sample powder were measured with a weight time of 0.1 sec. The saturation magnetization σs and the coercive force Hc were obtained from the BH curve. The processing constants were specified by the manufacturer. Specifically, it is as follows.

Intersection detection: least squares method M average score 0 H average score 0
Ms With: 8 Mr With: 8 Hc With: 8 SFD With: 8 S.M. Star Width: 8
Sampling time (seconds): 90
2-point correction P1 (Oe): 1000
2-point correction P2 (Oe): 4500

[Measurement of change in compression density (difference in powder density)]
The change in compression density was measured as follows. After packing 6.0 g of sample powder in the measuring container (inner diameter of the container: 20 mm) of the powder resistance measurement system (MCP-PD51 type manufactured by Mitsubishi Chemical Analytech Co., Ltd.), pressurization was started and 4 kN, The density of a circular green compact having a cross section of φ20 mm at the time when a load of 20 kN was applied was measured. From these results, the difference in the powder compact density at the load of 4 kN and 20 kN was obtained.
Powder density difference (g / cc) = Powder density at 20 kN (g / cc)-Cushion density at -4 kN (g / cc)

The mass ratios of Fe, Ni, and B in the molten metal raw materials in the production of the alloy powders of Comparative Examples and Examples are summarized in Table 1 below, and the evaluation results of the produced alloy powders are summarized in 2 and 3 below. The composition and sphericity are shown in both Tables 2 and 3.

As shown in Table 3, the FeNiB alloy powders of Examples 1 to 6 containing a predetermined amount of B have a sphericity of 0.80 or more, whereas the FeNi alloy powder of Comparative Example 1 containing no B has a sphericity of 0.80 or more. It was confirmed that the sphericity was 0.78 and less than 0.80. Further, according to the FeNiB alloy powders of Examples 1 to 6, the compression density change (compact density difference) is 0.51 g / cc to 0.77 g / cc, and Comparative Example 1 of 0.25 g / cc. It was confirmed that the alloy powder could be compressed more than the above (note that no substantial deformation of the particles of the alloy powder was observed in the green compact). In fact, in the FeNiB alloy powders of Examples 1 to 6, when the green compact is formed, the density can be set to 6.0 g / cm ³ to 6.5 g / cm ³ , and 5. It was confirmed that it can be higher than 9 g / cm ³ . According to the FeNiB alloy powders of Examples 1 to 6 containing a predetermined amount of B and having a sphericity of 0.80 or more, the FeNi alloy of Comparative Example 1 containing no B and having a sphericity of less than 0.80. It was confirmed that the density of the molded product can be increased and the excellent magnetic permeability μ'can be realized as compared with the powder.

On the other hand, in Comparative Example 2 in which the content of B is 1.7% by mass and exceeds 1.5% by mass, since B is contained, the sphericality can be 0.80 or more, but B is an excessive amount. As a result, it was confirmed that the magnetic permeability of the alloy powder was lower than that of Examples 1 to 6. That is, it was confirmed that high magnetic permeability, high saturation magnetization and low coercive force could not be realized for the magnetic characteristics.

Further, the FeNiB alloy powder 2 of Example 2 having an amount of Ni of 87% by mass and an amount of B of 0.07% by mass contains a predetermined amount of B and a relatively large amount of Ni, so that FeNiB of another example is contained. It was confirmed that the coercive force of the magnetic properties can be lower and the magnetic permeability can be higher than that of the alloy powder. Further, since the FeNiB alloy powder of Example 1 and the like contains a predetermined amount of B and a relatively small amount of Ni, the saturation magnetization of the magnetic properties can be made higher than that of the FeNiB alloy powder 2 of Example 2. confirmed. That is, it was confirmed that the desired magnetic characteristics can be obtained by appropriately changing the ratio of Fe and Ni while setting B to a predetermined content.

Claims (16)

An alloy powder containing Fe, Ni, and B, having a B content of 0.04 to 1.5% by mass and a sphericity of 0.80 or more. The alloy powder according to claim 1, wherein the content of B is 0.04 to 1.0% by mass. The alloy powder according to claim 1 or 2, wherein the cumulative 50% particle diameter (D50) on a volume basis measured by a laser diffraction type particle size distribution measuring device is 0.1 to 15 μm. The alloy powder according to any one of claims 1 to 3, wherein the content of B is 0.05 to 0.8% by mass. The alloy powder according to any one of claims 1 to 4, wherein the total content of Fe and Ni is 96% by mass or more. The alloy powder according to any one of claims 1 to 5, wherein the total content of Fe, Ni and B is 96.05% by mass or more. Any of claims 1 to 6, wherein the Fe content is 18 to 58% by mass, the Ni content is 40 to 80% by mass, and the B content is 0.13 to 0.6% by mass. The alloy powder described in Crab. Any of claims 1 to 6, wherein the Fe content is 6 to 38% by mass, the Ni content is 60 to 92% by mass, and the B content is 0.04 to 0.30% by mass. The alloy powder described in Crab. Any of claims 1 to 6, wherein the Fe content is 6 to 38% by mass, the Ni content is 60 to 92% by mass, and the B content is 0.04 to 0.11% by mass. The alloy powder described in Crab. A molten metal containing Fe, Ni, and B, wherein the content of B in the molten metal is 0.04 to 1.7% by mass is prepared.
A method for producing an alloy powder, which obtains an alloy powder by crushing and solidifying the molten metal by spraying a fluid on the flow of the falling molten metal while dropping the molten metal. The content of B in the molten metal is 0.04 to 1.0% by mass.
The method for producing an alloy powder according to claim 10. The method for producing an alloy powder according to claim 10, wherein the content of B in the molten metal is 0.05 to 0.8% by mass. The method for producing an alloy powder according to any one of claims 10 to 12, wherein the total content of Fe, Ni and B in the molten metal is 96.05% by mass or more. A soft magnetic material containing the alloy powder according to any one of claims 1 to 8 and a binder. A powder magnetic core containing the alloy powder according to any one of claims 1 to 8. A dust core obtained by molding the alloy powder according to any one of claims 1 to 8 or the soft magnetic material according to claim 14 into a predetermined shape and heating the obtained molded product to obtain a powder magnetic core. Manufacturing method.