WO2010073590A1 - Composite soft magnetic material and method for producing same - Google Patents

Abstract

Disclosed is a composite soft magnetic material which is characterized by being obtained by mixing, compacting and firing an iron powder, which has been subjected to an insulating treatment, a Sendust alloy powder and a binder.  The composite soft magnetic material is also characterized by comprising a main phase in which the iron powder and the Sendust alloy powder are compacted, and a grain boundary phase which is formed around the main phase and is mainly composed of the binder, and by having a ratio of the Sendust alloy in the main phase of 5% by mass or more, but less than 20% by mass, a saturation magnetic flux density at a magnetic field of 10 kA/m of 1 T or more, a coercivity of 260 A/m or less, and an iron loss (at 0.1 T, 10 kHz) of 20 W/kg or less.  Consequently, the composite soft magnetic material has characteristics of the Sendust alloy, namely a high magnetic permeability, low coercivity and low iron loss, while maintaining a high saturation magnetic flux density which is intrinsic to an iron powder.  Also disclosed is a method for producing the composite soft magnetic material.

Description

Composite soft magnetic material and manufacturing method thereof

The present invention relates to a composite soft magnetic material obtained by mixing and compacting an insulating iron powder and a sendust alloy powder together with a binder and firing the mixture, and a method for producing the same.
This application claims priority based on Japanese Patent Application No. 2008-330597 for which it applied to Japan on December 25, 2008, and uses the content here.

Electromagnetic components for electronic devices such as inverters, transformer cores, and choke coils are required to have stricter material properties as electronic devices become smaller and have higher performance. Conventionally, metal magnetic materials such as Sendust alloy and silicon steel, and oxide magnetic materials such as ferrite have been used as soft magnetic materials for such parts. However, metallic magnetic materials such as Sendust alloy have a high hardness when powdered, and there is a problem that it is difficult to increase the density by powder molding.
For example, in the production of high-density composite soft magnetic materials by powder molding, first, a metal soft magnetic powder having an insulating coating, and a raw material powder consisting of a lubricant powder and a binder added as needed are filled in a mold cavity. After that, a green compact having a desired shape is produced by pressure molding, and then the green compact is fired to produce a composite soft magnetic material.

Therefore, when the hardness of the powder itself used for molding is high, there is a problem that it is difficult to obtain a high pressure density as a green compact. For example, Sendust alloy has very little plastic deformation when processed at room temperature and can be pulverized by pulverization, but cannot be formed into a plate shape. Therefore, when Sendust alloy powder is molded to produce magnetic parts such as magnetic cores, plastic deformation hardly occurs. Therefore, Sendust alloy powder is simply connected with the added binder. Even if the permeability of the sendust alloy powder itself is high, there is a problem that a high permeability cannot be obtained when a dust core is used.

Therefore, conventionally, attempts have been made to improve the performance by mixing an oxide magnetic material and a metal magnetic material to form a composite.
For example, a method is known in which a metal magnetic powder such as permalloy is coated with an oxide magnetic material such as ferrite and then molded and heat-treated. (See Patent Document 1)
Also known is a composite magnetic material obtained by mixing a Sendust alloy powder having an oxide film, a highly compressible soft magnetic metal powder, a soft ferrite powder, and a binder, followed by sintering and sintering. (See Patent Document 2)

JP-A-56-38402 JP-A-6-236808

The soft magnetic composite material produced by coating the metal magnetic powder such as Permalloy with an oxide magnetic material such as ferrite has a problem that the magnetic properties deteriorate because the metal and ferrite easily react at the interface between them when heat-treated. Had.
Further, in the method of mixing Sendust alloy powder and other soft magnetic metal powder, since Sendust alloy powder is very hard, even if soft magnetic metal powder having good compressibility is mixed, 20 ton / cm ^2. A high pressure molding technique of a certain level is required, and there is a problem that only a product having a simple shape such as a cylindrical shape such as a dust core can be obtained.

The present invention has been proposed in view of such conventional circumstances, and its purpose is to select iron powders to be mixed with Sendust alloy powder, the range of their addition amount, and the respective particle size ranges. By suitably selecting and taking into account the conditions of the binder and the like, it is made into an optimal composition, while maintaining high saturation magnetic flux density inherent in iron powder, while high permeability, low coercivity, inherent in Sendust alloy powder, It is an object of the present invention to provide a composite soft magnetic material and a method for manufacturing the same, which can have the characteristics of low iron loss.

In order to achieve the above object, the composite soft magnetic material according to the present invention comprises an insulating iron powder, a sendust alloy powder, and a binder mixed and compacted and fired, and the iron powder and the sendust alloy powder are compacted. A fired main phase and a grain boundary phase mainly composed of a binder formed around the main phase are provided, and the proportion of Sendust alloy in the main phase is 5% by mass or more and less than 20% by mass. The saturation magnetic flux density is 1 T or more at a magnetic field of 10 kA / m, the coercive force is 260 A / m or less, and the iron loss (at 0.1 T, 10 kHz) is 20 W / kg or less.
In the composite soft magnetic material according to the present invention, the average particle size of the iron main phase formed by compacting and firing the iron powder is 20 to 50 μm, and the average particle size of the alloy main phase formed by compacting and firing the Sendust alloy powder. The thickness can be 50 to 120 μm.
In the composite soft magnetic material according to the present invention, pure iron powder having an Mg-containing oxide film can be used as the insulated iron powder.

The method for producing a composite soft magnetic material according to the present invention comprises a main phase formed by compacting at least mixed compacted and sintered iron powder, sendust alloy powder and binder, and then compacting the iron powder and sendust alloy powder. And a sendust alloy occupying the total mass of the insulated iron powder and sendust alloy powder in producing a composite soft magnetic material having a grain boundary phase mainly composed of a binder formed around the main phase. When the addition ratio of the powder is 5 mass% or more and less than 20 mass%, the insulated iron powder and Sendust alloy powder are mixed and compacted and fired to obtain a saturation magnetic flux density of 1 T or more at a magnetic field of 10 kA / m, a coercive force. A composite soft magnetic material having 260 A / m or less and iron loss (at 0.1 T, 10 kHz) of 20 W / kg or less is obtained.
In the present specification, unless otherwise specified, the addition ratio or blending ratio of Sendust alloy powder is the ratio of Sendust alloy powder to the total mass of Sendust alloy powder and the iron powder insulated with Mg-containing oxide coating or the like. It means a compounding ratio (mass%).
The method for producing a composite soft magnetic material according to the present invention is characterized by using an insulated iron powder having an average particle diameter of 20 to 50 μm and a sendust alloy powder having an average particle diameter of 50 to 120 μm.
The method for producing a composite soft magnetic material according to the present invention is characterized in that pure iron powder insulated with an Mg-containing oxide film is used as the insulated iron powder.

According to the present invention, while maintaining the high saturation magnetic flux density of the insulated iron powder, the soft magnetic characteristics such as low iron loss, low coercive force, and low eddy current loss of the proper amount of sendust alloy powder are effective. The composite soft magnetic material obtained in the above can be provided. Furthermore, according to the present invention, a composite that can be compacted at a pressure required for general powder molding without exhibiting the high molding force required for the conventional Sendust alloy powder molding and can exhibit the above-described characteristics. A soft magnetic material can be provided.
In the present invention, pure iron powder insulated with an Mg-containing oxide coating is used as the insulated iron powder to ensure high saturation magnetic flux density, low iron loss, low coercive force, and low eddy current loss. It is possible to get to.

FIG. 1 is a graph showing the relationship between the blending ratio of sendust alloy powder and the specific resistance in an example of a composite soft magnetic material according to the present invention. FIG. 2 is a diagram showing the relationship between the blending ratio of the sendust alloy powder and the saturation magnetic flux density in the example of the composite soft magnetic material according to the present invention. FIG. 3 is a diagram showing the relationship between the saturation magnetic flux density and the loss in the example of the composite soft magnetic material according to the present invention. FIG. 4 is a diagram showing the relationship between the blending ratio of the sendust alloy powder and the loss in the example of the composite soft magnetic material according to the present invention. FIG. 5 is a diagram showing the relationship between the blending ratio of Sendust alloy powder and mechanical strength in the example of the composite soft magnetic material according to the present invention.

Hereinafter, a composite soft magnetic material to which the present invention is applied and a manufacturing method thereof will be described in detail.
In order to produce a composite soft magnetic material using the present invention, for example, using a compacting device such as a press molding machine, as a raw material powder of the composite soft magnetic material, for example, pure iron powder with an MgO-based insulating coating, and Sendust alloy powder, A powder compact having a predetermined shape can be obtained by filling the mixed powder obtained by adding and mixing a binder and a lubricant as necessary into a mold cavity of a compacting device, followed by pressure molding. Thereafter, the obtained green compact is fired in a predetermined temperature range, whereby a composite soft magnetic material having a desired shape can be obtained.

Insulated pure iron powder used in the present invention is, for example, an Mg-containing oxide in which a Mg—Fe—O ternary oxide deposition film containing (Mg, Fe) O is coated on the surface of pure iron particles. Wet powder-coated pure iron powder, phosphate-coated pure iron powder, or a wet solution such as silica sol-gel solution (silicate) or alumina sol-gel solution is mixed and coated on the surface of pure iron powder, then dried and fired However, the present invention is not limited to this, and it is possible to widely apply insulated pure iron powder having a structure in which pure iron powder is coated with an insulating coating layer. it can.

The Mg-containing oxide-coated pure iron powder coated with the Mg—Fe—O ternary oxide deposited film is obtained, for example, by the following production method (A), (B), (C) or (D). be able to.
(A) Pure iron powder is subjected to an oxidation treatment in an oxidizing atmosphere at room temperature to 500 ° C., and then mixed powder obtained by adding and mixing Mg powder to this powder is temperature: 150 to 1100 ° C., pressure When heated in an inert gas atmosphere or vacuum atmosphere of 1 × 10 ⁻¹² to 1 × 10 ⁻¹ MPa and further heated in an oxidizing atmosphere at a temperature of 50 to 400 ° C. as necessary, the surface of pure iron powder Mg-containing oxide-coated pure iron particles having an oxide insulating film containing Mg are obtained.
(B) After subjecting the pure iron powder to the oxidation treatment described above, after adding and mixing the silicon monoxide powder, or while mixing, heating in a vacuum atmosphere at a temperature of 600 to 1200 ° C., After adding and mixing Mg powder, or heating while mixing in a vacuum atmosphere at a temperature of 400 to 800 ° C., an Mg—Si containing oxide film is formed on the surface of pure iron powder. A material-coated pure iron powder is obtained.

(C) After subjecting the pure iron powder to the above-described oxidation treatment, the silicon monoxide powder and the Mg powder are simultaneously added and mixed, or while mixing, in a vacuum atmosphere at a temperature of 400 to 1200 ° C. When heated, an Mg—Si-containing oxide-coated soft magnetic powder in which an Mg—Si-containing oxide film is formed on the surface of pure iron powder is obtained.
(D) After the above-described oxidation treatment is applied to pure iron powder, after adding and mixing Mg powder or while mixing, heating in a vacuum atmosphere at a temperature of 400 to 800 ° C., the pure iron powder An Mg-containing oxide-coated pure iron powder having a Mg-containing oxide film formed on the surface is obtained.
After further adding and mixing the silicon monoxide powder to this powder and heating it in a vacuum atmosphere at a temperature of 600 to 1200 ° C., the Mg—Si-containing oxide film is formed on the surface of the pure iron powder. Thus, an Mg—Si-containing oxide-coated soft magnetic powder with a formed thereon can be obtained.
The addition amount of the silicon monoxide powder can be in the range of 0.01 to 1% by mass, and the addition amount of the Mg powder can be in the range of 0.05 to 1% by mass. The vacuum atmosphere may be a vacuum atmosphere at a pressure of 1 × 10 ⁻¹² to 1 × 10 ⁻¹ MPa.

The Mg-containing oxide-coated pure iron particles obtained by these production methods have remarkably excellent coating adhesion of the Mg—Fe—O ternary oxide deposited film containing (Mg, Fe) O, Even if these particles are pressed to produce a green compact, the insulating coating is less likely to be broken and peeled off.
The oxide-coated pure iron powder is preferably a powder having an average particle size in the range of 20 to 50 μm. The reason is that if the average particle size is too small, the compressibility of the powder decreases and the value of the saturation magnetic flux density decreases, which is not preferable. On the other hand, if the average particle size is too large, the eddy current inside the soft magnetic powder is not preferable. This is because the magnetic permeability at a high frequency is likely to increase and decrease.

In addition to the oxide-coated pure iron powder, a sendust alloy (for example, composition ratio: 10 mass% Si-6 mass% Al-residual Fe) powder is prepared. As this Sendust alloy powder, a powder having a particle size range of 50 to 120 μm can be used.
Once these powders are prepared, the oxide-coated pure iron powder and Sendust alloy powder are each mixed with a binder material containing Si, such as silicone resin as a binder material, and each powder is made into a silicone resin-coated powder. .
In order to coat the oxide-coated pure iron powder with the binder material, about 0.01 to 1% by mass of the binder material is added and stirred and coated, and then the temperature is in the range of 150 to 250 ° C, more preferably 200 to 250 ° C. Can be baked and coated in the range of. In order to coat the binder material on the Sendust alloy powder, after adding about 0.05 to 3% by mass of the binder material and stirring and coating, the temperature is in the range of 80 to 250 ° C., more preferably in the range of 100 to 200 ° C. It can be baked and coated by heating.

When the oxide-coated pure iron powder is baked with a binder material, the baking temperature can be selected from a range of 150 to 250 ° C. A decrease in specific resistance, which is considered to be caused by damage to the insulation coating, is observed, and if it exceeds 250 ° C., the binder material becomes hard and the packing density during molding is decreased, which is not desirable. Even within this range, a baking temperature in the range of 200 to 250 ° C. is more preferable in order to obtain higher density and specific resistance.
When baking is performed by coating a sendust alloy powder with a binder material, a temperature range of 80 to 250 ° C can be selected as the baking temperature. If the temperature is outside this range, a decrease in density or variation may be observed during molding. At temperatures exceeding 250 ° C., the specific resistance is decreased, which is not desirable. Even within this range, a baking temperature in the range of 100 to 200 ° C. is more preferable in order to obtain higher density and specific resistance.

The ratio of the mass of the Sendust alloy powder coated with the binder material to the total mass of the oxide-coated pure iron powder coated with these binder materials and the Sendust alloy powder coated with the binder material is 5% by mass or more and 20% by mass. These powders are mixed so as to be less than the minimum, accommodated in a mold of a compacting apparatus, and warm-molded into a desired shape with a molding temperature of about 8 to 10 Ton / cm ² at a mold temperature of 80 to 150 ° C. and consolidated. Let it be the body.
The molding pressure of about 8 to 10 Ton / cm ² used here is much lower than the conventional molding pressure of about ²⁰ Ton / cm ² used for compacting Sendust alloy powder, and the compacting force used for general powder molding methods. Therefore, it is possible to use the Sendust alloy powder to produce an excellent composite soft magnetic material according to the present invention even at a general molding pressure.
Thereafter, the compact is fired at a temperature of 500 ° C. to 800 ° C. for about 1 hour in a vacuum atmosphere, an inert gas atmosphere (Ar, N ₂ ), or in a non-oxidizing atmosphere (H ₂ atmosphere) to obtain the desired composite. A soft magnetic material can be obtained.
By the above-described consolidation treatment and firing treatment, the pure iron powder subjected to insulation treatment is consolidated into an iron main phase, and Sendust alloy powder is consolidated into a Sendust alloy main phase. The target composite soft magnetic material can be obtained by exhibiting a structure in which a grain boundary phase formed as a result of firing the binder material so as to be present at those grain boundaries with respect to the main phase constituted by.

The composite soft magnetic material manufactured as described above has low loss in the high frequency range (10 to 20 kHz), excellent iron loss, hysteresis loss, coercive force, low eddy current loss, and high specific resistance. Has soft magnetic properties. This is because the composite soft magnetic material of the present invention covers pure iron powder with a film of the Mg—Fe—O ternary oxide deposited film containing (Mg, Fe) O having excellent insulation and adhesion. The pure iron powder with a suitable particle size range is mixed with a suitable amount of Sendust alloy powder with a suitable particle size range, consolidated, and fired to form a composite soft magnetic material. This is because the high permeability, low coercive force, and low iron loss characteristics of the sendust alloy can be exhibited while maintaining the high saturation magnetic flux density of the pure iron powder.
In addition, the insulation treatment of the pure iron powder is not limited to the above-described coating with the Mg—Fe—O ternary oxide deposited film containing (Mg, Fe) O, and the phosphate-coated pure iron powder, A similar composite soft magnetic material can be obtained also by a film subjected to another insulation treatment.

The composite soft magnetic material obtained by mixing pure iron powder and Sendust alloy powder and compacting as described above is mixed with soft pure iron powder in an appropriate blending ratio compared to Sendust alloy, compacted, and fired. Therefore, sufficient magnetic properties can be exhibited at a molding pressure of about 8 to 10 Ton / cm ² .
The composite soft magnetic material of the present invention has a low loss in the high frequency range (10 to 20 kHz) inherent to the sendust alloy powder by setting the addition ratio of the sendust alloy powder in the range of 5% by mass or more and less than 20% by mass. Excellent soft magnetic properties such as low iron loss, hysteresis loss, coercive force, low eddy current loss, and high specific resistance can be obtained. If the send rate of the sendust alloy powder is less than the above range, these characteristics cannot be exhibited effectively. In addition, if the addition ratio of Sendust alloy powder is too large, the amount of pure iron powder decreases, so it becomes difficult to obtain a high saturation magnetic flux density and the pressure required during molding becomes high, and the molding pressure in the above range is good. It becomes difficult to obtain the density.

Examples of the electromagnetic circuit component configured using the composite soft magnetic material of the present invention include a magnetic core, a motor core, a generator core, a solenoid core, an ignition core, a reactor core, a transformer core, a choke coil core, and a magnetic sensor core. These are electromagnetic circuit components that can exhibit excellent characteristics in any case.
Examples of electric devices incorporating these electromagnetic circuit components include an electric motor, a generator, a solenoid, an injector, an electromagnetically driven valve, an inverter, a converter, a transformer, a relay, or a magnetic sensor system. The composite soft magnetic material of the present invention has the effect of contributing to high efficiency, high performance, small size and light weight of these electric devices.

Hereinafter, the effects of the present invention will be made clearer by examples. In addition, this invention is not limited to a following example, In the range which does not change the summary, it can change suitably and can implement.

Powder with particle size D50 (= 20 μm to 50 μm) as pure Mg powder coated with Mg oxide and D50 (= 50 μm to 120 μm) as sendust alloy (composition ratio: 10 mass% Si-6 mass% Al-residual Fe) powder particle diameter ) Powder was prepared. For measurement of the particle size, MICROTRAC FRA manufactured by LEED & NORTHRUP was used.
As pure Mg powder coated with Mg oxide, the pure iron powder was heat-treated at 220 ° C. in the atmosphere to form an oxide film on the surface, and 0.3% by mass of Mg powder was added to the soft magnetic powder. Blending and rolling this blended powder with a granulation rolling agitation and mixing device in vacuum at 650 ° C. for 1 hour forms an Mg-containing oxide film of (Mg, Fe) O with a film thickness of 30 nm Insulated pure iron powder was used.
As other insulation-coated pure iron powder, iron phosphate-coated iron powder S110i manufactured by Heganes Japan was prepared, and as a comparative sample, pure iron powder having a particle size equivalent to the above was prepared. .

Add 0.5% by mass of a silicone resin as a binder material to these powders and bake at 250 ° C., and add 1% by mass of silicone resin to Sendust alloy powder and heat to 150 ° C. for baking. Went. Subsequently, among these powders, Mg oxide-coated pure iron powder and Sendust alloy powder in the proportion of Sendust alloy powder are 0 mass%, 5 mass%, 7 mass%, 10 mass%, 20 mass%, and Samples mixed and divided at a ratio of 50% by mass were prepared, and each of these samples was consolidated into a ring shape having an outer shape of 35 mm, an inner diameter of 25 mm, and a height of 5 mm at a molding temperature of 150 ° C. and a molding pressure of 8 Ton / cm ² , Each sample was made.

For the obtained samples, the blending ratio of Sendust alloy powder (the blending ratio of Sendust alloy powder in the total mass of oxide-coated pure iron powder and Sendust alloy powder, mass%) is displayed in Table 1, and water density (g / ^cm 3), the specific resistance (μΩm), μmax, the saturation magnetic flux density when a magnetic field _{10kA / m (B 10k a /} m: T), the coercive force (Hc: a / m), iron loss (total Table 1 also shows the results of measuring the loss, hysteresis loss, eddy current loss) and mechanical strength (compression crushing strength: N / mm ² ).

FIG. 1 is a graph plotting the relationship between the blending ratio and specific resistance of Sendust alloy powder shown in Table 1. According to the results shown in FIG. 1, the specific resistance value is remarkably low at 0% by mass in the blending ratio of Sendust alloy powder, but the specific resistance value increases rapidly in the sample to which 5% by mass of Sendust alloy powder is added. . Further, when the blending ratio is 20% by mass or more, the reduction ratio of specific resistance increases. Therefore, the blending ratio of Sendust alloy powder is preferably 5% by mass or more and less than 20% by mass.

FIG. 2 is a graph plotting the relationship between the blending ratio of Sendust alloy powder shown in Table 1 and the saturation magnetic flux density. According to the results shown in FIG. 2, the saturation magnetic flux density rapidly decreases when the blending ratio is 20% by mass or more. Therefore, the blending ratio of Sendust alloy powder to oxide-coated pure iron powder is preferably 5% by mass or more and less than 20% by mass in order to obtain a saturation magnetic flux density of 1T or more at a magnetic field of 10 kA / m, and a magnetic field of 10 kA / m. In order to obtain a saturation magnetic flux density of 1.1 T, 5 mass% or more and 10 mass% or less are more preferable.

FIG. 3 is a graph plotting the relationship between the magnetic flux density and the iron loss at the magnetic field of 10 kA / m shown in Table 1 (when the magnetic flux density is 0.1 T and the frequency is 10 kHz). According to the results shown in FIG. 3, the iron loss can be reduced without reducing the magnetic flux density by blending the sendust alloy powder.
FIG. 4 is a graph plotting the relationship between the blending ratio of the Sendust alloy powder shown in Table 1 and the loss. According to the result shown in FIG. 4, a blending ratio of less than 20% by mass is preferable for the loss. Moreover, when the blending ratio of Sendust alloy powder is 5 mass% or more and less than 20 mass%, an iron loss (at a magnetic flux density of 0.1 T and a frequency of 10 kHz) of 20 W / kg or less can be realized.

FIG. 5 is a graph plotting the relationship between the blending ratio of Sendust alloy powder shown in Table 1 and the mechanical strength. According to the results shown in FIG. 5, it is clear that the crushing strength has a mechanical strength peak between 5 and 10% by mass, but there is no problem in the practical range for the blending ratio of Sendust alloy powder. It turns out that it is.

Next, a silicone resin-coated sendust in which 0.5% by mass of a silicone resin is mixed with pure iron powder and then baked at 250 ° C. is mixed with 1% by mass of silicone resin and baked at 200 ° C. The alloy powder was blended so that the blending ratio of the silicone resin-coated Sendust alloy powder in the total mass of the silicone resin-coated pure iron powder and the silicone resin-coated Sendust alloy powder was 7% by mass. These were mixed and compacted at a molding temperature of 150 ° C. and a molding pressure of 8 Ton / cm ² , and then fired at 500 ° C. or 650 ° C. to prepare each sample. The measured values of the specific resistance of each sample are shown in Table 2 below.

According to the results shown in Table 2, in order to achieve good iron loss (small numerical value) and lower hysteresis loss, a higher firing temperature is preferable, and a good specific resistance can be obtained at a firing temperature of 500 ° C. In order to obtain better iron loss, a firing temperature of 650 ° C. is preferable.

Next, with respect to the silicone resin-coated Sendust alloy powder obtained by mixing 1% by mass of silicone resin with Sendust alloy powder and baking at 150 ° C., 0.5% by mass of silicone resin is mixed to 150 ° C., 200 ° C., 250 ° C. , And 270 ° C., the blending ratio of the silicone resin-coated Sendust alloy powder occupying the total mass of the silicone resin-coated Sendust alloy powder and the silicone resin-coated Sendiron alloy powder is 7%. %. These were consolidated at a molding temperature of 150 ° C. and a molding pressure of 8 Ton / cm ² , and then fired at 650 ° C. to prepare each sample. The measured values of density, specific resistance and iron loss of each sample are shown in Table 3 below.

According to the test results shown in Table 3, the baking temperature of the silicone resin with respect to the pure iron powder can be selected in the range of 150 to 250 ° C, more preferably in the range of 200 to 250 ° C.

Silicone resin-coated pure iron powder obtained by mixing 0.5% by mass of a silicone resin with pure iron powder and baking at 250 ° C. and 1% by mass of silicone resin were mixed at 50 ° C., 80 ° C., 100 ° C., 150 ° C., The silicone resin-coated Sendust alloy powder occupies the total mass of the silicone resin-coated pure iron powder and the silicone resin-coated Sendust alloy powder. It mix | blended so that a compounding ratio might be 7 mass%. These were consolidated at a molding temperature of 150 ° C. and a molding pressure of 8 Ton / cm ² , and then fired at 650 ° C. to prepare each sample. The measured values of density, specific resistance, and iron loss of each sample are shown in Table 4 below.

According to the test results shown in Table 4, the baking temperature of the silicone resin in the Sendust alloy powder can be selected in the range of 80 to 250 ° C, more preferably in the range of 100 to 200 ° C.

From the test results described above, by implementing the present invention, by adding Sendust alloy powder to pure iron powder and compacting with a molding pressure of 8 Ton / cm ² , saturation magnetic flux density of 1 T or more at a magnetic field of 10 kA / m or more. It was revealed that a composite soft magnetic material having excellent soft magnetic properties having a coercive force of 260 A / m or less and an iron loss (at 0.1 T, 10 kHz) of 20 W / kg or less can be produced.

According to the present invention, while maintaining the high saturation magnetic flux density of the insulated iron powder, the soft magnetic characteristics such as low iron loss, low coercive force, and low eddy current loss of the proper amount of sendust alloy powder are effective. The composite soft magnetic material obtained in the above can be provided.

Claims (6)

1. Insulated iron powder, Sendust alloy powder, and binder are mixed, consolidated, and fired. A grain boundary phase as a main component, the proportion of Sendust alloy in the main phase is 5 mass% or more and less than 20 mass%, a saturation magnetic flux density of 1 T or more at a magnetic field of 10 kA / m, and a coercive force of 260 A. / M or less, iron loss (at 0.1 T, 10 kHz) 20 W / kg or less, composite soft magnetic material,
2. In the main phase in which the insulated iron powder and Sendust alloy powder are consolidated and fired, the average particle size of the iron main phase is 20 to 50 μm, and the average particle size of the Sendust alloy main phase is 50 to 120 μm. The composite soft magnetic material according to claim 1.
3. 3. The composite soft magnetic material according to claim 1, wherein the insulated iron powder is a pure iron powder comprising an Mg-containing oxide film.
4. Insulated iron powder, Sendust alloy powder and binder are mixed and compacted at least, and then fired to produce a main phase formed by compacting and firing the iron powder and Sendust alloy powder, and around the main phase. In producing a composite soft magnetic material having a grain boundary phase mainly composed of a binder,
   The ratio of addition of Sendust alloy powder to the total mass of insulated iron powder and Sendust alloy powder is 5% by mass or more and less than 20% by mass, and the insulated iron powder and Sendust alloy powder are mixed and consolidated and fired. Thus, a composite soft magnetic material having a saturation magnetic flux density of 1 T or more at a magnetic field of 10 kA / m, a coercive force of 260 A / m or less, and an iron loss (at 0.1 T, 10 kHz) of 20 W / kg or less is obtained. A method for producing a soft magnetic material.
5. 5. The method for producing a composite soft magnetic material according to claim 4, wherein an insulated iron powder having an average particle size of 20 to 50 μm is used and a sendust alloy powder having an average particle size of 50 to 120 μm is used.
6. 6. The method for producing a composite soft magnetic material according to claim 4, wherein pure iron powder insulated with an Mg-containing oxide coating is used as the insulated iron powder.

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