JP2006135164A - Soft magnetic material and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soft magnetic material having a high saturation magnetic flux density B<SB>s</SB>and a manufacturing method thereof by improving the compacting density of a compact. <P>SOLUTION: The soft magnetic material consists of a plurality of composite magnetic particles 30a and a plurality of composite magnetic particles 30b. The content of the plurality of composite magnetic particles 30a, each of which has an alloy particle 10a and an insulating film 20a surrounding the surface of the alloy particle 10a, is ≥65 mass% and ≤85 mass%. The content of the plurality of composite magnetic particles 30b, each of which has a highly compressible soft magnetic particle 10b and an insulating film 20b surrounding the highly compressible soft magnetic particle 10b, is ≥15 mass% and ≤35 mass%. The mean particle diameter of the alloy particle 10a lies between 3 μm and 300 μm. The mean particle diameter of the highly compressible soft magnetic particle 10b is ≥3 μm and ≤300 μm, and is ≤ the mean particle diameter of the alloy particle 10a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a soft magnetic material and a method for manufacturing the same, and more particularly to a soft magnetic material capable of improving a molding density and a method for manufacturing the same.

  A soft magnetic material is used for an electric device having a solenoid valve, a motor, or an electric circuit. This soft magnetic material is composed of a plurality of composite magnetic particles, and the composite magnetic particles have, for example, metal magnetic particles made of pure iron and an insulating coating made of, for example, phosphate covering the surface thereof. . Soft magnetic materials are required to have a magnetic property that can provide a large magnetic flux density by applying a small magnetic field and a magnetic property that can react sensitively to an external magnetic field.

  When a dust core made of this soft magnetic material is used in an alternating magnetic field, an energy loss called iron loss occurs. This iron loss is represented by the sum of hysteresis loss and eddy current loss. Hysteresis loss is energy loss caused by energy required to change the magnetic flux density of soft magnetic material, and eddy current loss is energy loss caused mainly by eddy current flowing between the metal magnetic particles constituting the soft magnetic material. is there. Hysteresis loss is proportional to the operating frequency, and eddy current loss is proportional to the square of the operating frequency. For this reason, hysteresis loss is predominant in the low frequency region, and eddy current loss is predominant in the high frequency region.

The dust core is required to have magnetic characteristics that reduce the occurrence of iron loss, that is, high AC magnetic characteristics. In order to realize this, it is required to increase the magnetic permeability μ, the saturation magnetic flux density B _s, and the electrical resistivity ρ of the soft magnetic material and to reduce the coercive force H _c of the soft magnetic material. Since pure iron, which is a raw material for conventional soft magnetic materials, has magnetic anisotropy, it is difficult to move and rotate the domain wall, and the permeability μ is small. For this reason, there is a limit to improving the AC magnetic properties of soft magnetic materials made of pure iron.

As a method for improving the AC magnetic characteristics of the dust core, alloy particles such as Fe—Si alloy and Fe—Al alloy having a larger magnetic permeability μ and electric resistivity ρ and a smaller coercive force H _c than pure iron are used. A method for producing a soft magnetic material by using the same can be considered. However, since the hardness of these alloy particles is larger than that of pure iron, the soft magnetic material produced using the alloy particles has poor moldability, and as a result, there is a problem that the density of the obtained molded body is low. . As a result of the low molding density of the compact, the saturation magnetic flux density has been reduced.

  Here, technologies relating to soft magnetic materials using alloy particles are disclosed in, for example, Japanese Patent Application Laid-Open No. 6-236808 (Patent Document 1) and Japanese Patent Publication No. 6-82577 (Patent Document 2). Patent Document 1 discloses that one or two types of iron alloy powders selected from Sendust and Fe—Si based alloys having a particle size of 200 μm or less and having an oxide film on the surface thereof, and high compression having a particle size of 200 μm or less. A mixture in which a soft soft magnetic metal powder is mixed in a predetermined ratio, or a mixture in which the iron alloy powder, the high compressibility soft magnetic metal powder and a soft ferrite powder having an average particle size of 5 μm or less are mixed in a predetermined ratio. Is disclosed in which an oxide magnetic material is bonded through a binder.

Patent Document 2 discloses a Fe-Si alloy powder magnetic core manufactured by a water atomization method, having an average particle diameter of 10 to 100 μm, containing Si and oxygen at a predetermined ratio, and the balance being substantially the same. A powder magnetic core is disclosed in which an alloy powder made of Fe is used.
JP-A-6-236808 Japanese Patent Publication No. 6-82577

  However, both of the oxide magnetic material and the dust core obtained in Patent Documents 1 and 2 have a low molding density of the molded body, and the above problems cannot be solved. In particular, Patent Document 1 describes that the density of the obtained molded body was less than 6.0.

Accordingly, an object of the present invention is to provide a soft magnetic material having a high saturation magnetic flux density B _s and a method for producing the same by improving the molding density of the compact.

  The soft magnetic material of the present invention includes a plurality of first composite magnetic particles and a plurality of second composite magnetic particles. The plurality of first composite magnetic particles have alloy particles and an insulating coating surrounding the surface of the alloy particles, and the content is 65% by mass or more and 85% by mass or less. The plurality of second composite magnetic particles have high-compressibility soft magnetic particles and an insulating coating surrounding the high-compression soft magnetic particles, and the content is 15% by mass or more and 35% by mass or less. The average particle size of the alloy particles is 3 μm or more and 300 μm or less. The average particle size of the highly compressible soft magnetic particles is 3 μm or more and 300 μm or less, and less than the average particle size of the alloy particles.

  The method for producing a soft magnetic material of the present invention includes a step of producing a plurality of first composite magnetic particles having a form in which an insulating coating is formed on the surface of an alloy particle, and an insulating coating on the surface of the highly compressible soft magnetic particle. A step of producing a plurality of second composite magnetic particles having a formed form, a first composite magnetic particle having a content of 65% by mass to 85% by mass, and a content of 15% by mass to 35% by mass And a mixed powder production step of producing a mixed powder obtained by mixing the second composite magnetic particles. The average particle size of the alloy particles is 3 μm or more and 300 μm or less, the average particle size of the highly compressible soft magnetic particles is 3 μm or more and 300 μm or less, and is less than the average particle size of the alloy particles.

According to the soft magnetic material and the method for producing the same of the present invention, the first composite magnetic particles have alloy particles that are superior in magnetic properties as compared with pure iron. By setting the content of the first composite magnetic particles to 65% by mass or more, high AC magnetic characteristics that cannot be achieved by a soft magnetic material composed only of composite magnetic particles coated with pure iron with an insulating coating are obtained. Can do. In addition, since the highly compressible soft magnetic particles are excellent in moldability as compared with the alloy particles, by setting the content of the second composite magnetic particles to 15% by mass or more, gaps between the plurality of first composite magnetic particles are formed. The second composite magnetic particles can be sufficiently filled. Thereby, the moldability of the soft magnetic material can be improved, and the molding density of the molded body of the soft magnetic material can be improved. As a result, a soft magnetic material having a high saturation magnetic flux density B _s can be obtained.

  Moreover, since the particle | grains become difficult to oxidize by making the average particle diameter of an alloy particle and a highly compressible soft-magnetic particle into 3 micrometers or more, the fall of the magnetic characteristic of a soft-magnetic material can be suppressed. Moreover, it can suppress that the compressibility of mixed powder falls at the time of shaping | molding because the average particle diameter of an alloy particle and a highly compressible soft magnetic particle shall be 300 micrometers or less. Thereby, it can prevent that the density of the molded object obtained by the formation process does not fall, and handling becomes difficult.

  Furthermore, by making the average particle size of the highly compressible soft magnetic particles equal to or less than the average particle size of the alloy particles, the surface area of the highly compressible soft magnetic particles is increased, and the content is 15% by mass or more and 35% by mass or less. However, it is possible to realize a state in which the highly compressible soft magnetic particles surround the alloy particles.

  In the present specification, “alloy particles” are Fe—Si alloys, Fe—Ni alloys, Fe—Co alloys, Fe—Al alloys, and Fe—Al—Si alloys, and contain Si. In some cases, the Si content exceeds 2.5% by mass, or when Al is included, it means that the alloy contains particles having an Al content exceeding 6% by mass.

  In the present specification, “highly compressible soft magnetic particles” means pure iron, an Fe—Si alloy having an Si content of 2.5% by mass or less, and an Fe—Al alloy having an Al content of 6% or less. It is meant to include the particles.

  In the soft magnetic material of the present invention, preferably, the organic substance has a content of 0.01% by mass to 0.3% by mass and the inorganic substance has a content of 0.001% by mass to 0.1% by mass. One is further provided.

  Thereby, an organic substance or an inorganic substance is interposed between the first and second composite magnetic particles. By setting the content of the organic substance to 0.01% by mass or more, the organic substance bends under stress during pressure molding, and functions as a lubricant between the first and second composite magnetic particles. Further, when heat treatment is performed after molding, the organic matter is softened by heat and enters the gap between the first and second composite magnetic particles, thereby providing insulation between the alloy particles and the highly compressible soft magnetic particles. Can be increased. On the other hand, when the content of the organic substance is 0.3% by mass or less, the density of the magnetic part of the soft magnetic material is increased, so that the AC magnetic characteristics can be kept high.

In addition, when the content of the inorganic substance is 0.001% by mass or more, the inorganic substance is broken along the cleavage plane due to the stress during pressure molding, and lubricity between the first and second composite magnetic particles Play a role to improve. Thus, molding density of the molded body can be further enhanced, it is possible to obtain a soft magnetic material having a high saturation magnetic flux density B _s. On the other hand, when the content of the inorganic substance is 0.1% by mass or less, it is possible to prevent the molding density from being lowered due to an excessively large proportion of the inorganic substance in the soft magnetic material.

  In the soft magnetic material of the present invention, the ratio of the average particle size of the highly compressible soft magnetic particles to the average particle size of the alloy particles is preferably 0.4 or more and 1.0 or less. Thereby, the compression moldability of the soft magnetic material is increased, and the molding density can be further improved.

  In the soft magnetic material of the present invention, preferably, the highly compressible soft magnetic particles are pure iron, an Fe—Si alloy having an Si content of 2.5% by mass or less, and an Fe—Al alloy having an Al content of 6% or less. At least one selected from the group consisting of: These materials are suitable as highly compressible soft magnetic particles.

  Preferably, the method for producing a soft magnetic material of the present invention further includes an alloy particle heat treatment step of heat treating the alloy particles at 800 ° C. or higher and 1400 ° C. or lower.

  By heat-treating the alloy particles at a temperature of 800 ° C. or higher, many strains (dislocations and defects) existing inside the alloy particles can be sufficiently eliminated, and the magnetic properties of the soft magnetic material can be further improved. it can. Moreover, it can prevent that alloy particles sinter and solidify by heat-processing at the temperature of 1400 degrees C or less.

  Preferably, the method for producing a soft magnetic material of the present invention further includes a step of pressure-molding the mixed powder at a pressure of 980 MPa or more to produce a molded body, and a molded body heat treatment step of heat-treating the molded body.

By press molding at a pressure of 980 MPa or more, the soft magnetic material can be densified. As a result, the saturation magnetic flux density B _s can be improved, and the AC magnetic characteristics can be improved. Moreover, the distortion of the alloy particles caused by pressurization can be eliminated by heat-treating the compact.

  Preferably, in the method for producing a soft magnetic material of the present invention, in the compact heat treatment step, the lower one of the thermal decomposition temperature of the insulating coating of the first composite magnetic particles and the thermal decomposition temperature of the insulating coating of the second composite magnetic particles. The molded body is heat-treated at a temperature lower than the temperature of 300 ° C. or higher.

  Thereby, distortion of the alloy particles caused by compression molding can be sufficiently eliminated while suppressing increase in eddy current loss due to thermal decomposition of the insulating coating.

According to the soft magnetic material and the method for producing the same of the present invention, the molding density of the molded body can be improved, whereby a soft magnetic material having a high saturation magnetic flux density B _s can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is an enlarged schematic diagram showing a molded body produced using the soft magnetic material in Embodiment 1 of the present invention. Referring to FIG. 1, the soft magnetic material of the present embodiment includes two types of composite magnetic particles 30 a and 30 b and an organic substance 40. An organic substance 40 is interposed between each of the plurality of composite magnetic particles 30a and 30b. The composite magnetic particle 30a as the first composite magnetic particle has an alloy particle 10a and an insulating coating 20a. An insulating coating 20a is formed so as to surround the surface of the alloy particle 10a. Further, the composite magnetic particle 30b as the second composite magnetic particle has a highly compressible soft magnetic particle 10b and an insulating coating 20b. An insulating coating 20b is formed so as to surround the surface of the highly compressible soft magnetic particles 10b.

  The ratio (content) of the composite magnetic particles 30a in the soft magnetic material is 65% by mass or more and 85% by mass or less. Further, the ratio (content) of the composite magnetic particles 30b in the soft magnetic material is 15% by mass or more and 35% by mass or less. Moreover, the ratio (content) of the organic substance 40 is 0.01 mass% or more and 0.3 mass% or less.

  The average particle diameter of the alloy particles 10a is 3 μm or more and 300 μm or less. The average particle size of the highly compressible soft magnetic particles 10b is not less than 3 μm and not more than 300 μm, and is not more than the average particle size of the alloy particles 10a. The ratio of the average particle size of the highly compressible soft magnetic particles 10b to the average particle size of the alloy particles 10a is preferably 0.4 or more and 1.0 or less.

  The average particle diameter means the particle diameter of particles in which the sum of masses from the smaller particle diameter reaches 50% of the total mass in the histogram of particle diameters measured by the sieving method, that is, 50% particle diameter D. .

  The alloy particle 10a is, for example, a Fe—Si alloy, a Fe—Ni alloy, a Fe—Co alloy, a Fe—Al alloy, or a Fe—Al—Si alloy, and when Si is contained, When the proportion (Si content) exceeds 2.5 mass% or Al is contained, the Al content is made of an alloy exceeding 6 mass%. The highly compressible soft magnetic particles 10b are, for example, pure iron, Fe-Si alloys in which the proportion of Si in the alloy (Si content) is 2.5 mass% or less, and the proportion of Al in the alloy (Al content) (Amount) is made of Fe-Al alloy or the like of 6% or less.

  The alloy particles are not limited to those made of the above materials, and may be any material having magnetic properties substantially equivalent to those of the above materials. Further, the highly compressible soft magnetic particles are not limited to those made of the above-described materials, and may be any materials having substantially the same magnetic properties and moldability as the above-mentioned materials.

  The insulating coating 20a and the insulating coating 20b function as an insulating layer between the alloy particles 10a and the highly compressible soft magnetic particles 10b. The electrical resistivity ρ of the soft magnetic material can be increased by covering the alloy particles 10a with the insulating coating 20a and covering the highly compressible soft magnetic particles 10b with the insulating coating 20b. Thereby, it can suppress that an eddy current flows between the alloy particle 10a and the highly compressible soft-magnetic particle 10b, and can reduce the iron loss of the molded object of a soft magnetic material resulting from an eddy-current loss.

  The thickness of the insulating coatings 20a and 20b is preferably 0.005 μm or more and 20 μm or less. By setting the thickness of the insulating coatings 20a and 20b to 0.005 μm or more, energy loss due to eddy current can be effectively suppressed. Further, by setting the thickness of the insulating coatings 20a and 20b to 20 μm or less, the proportion of the insulating coatings 20a and 20b in the soft magnetic material does not become too large. For this reason, it can prevent that the magnetic flux density of a soft-magnetic material falls remarkably.

  The insulating coatings 20a and 20b are made of an oxide insulator such as iron phosphate, aluminum phosphate, manganese phosphate, zinc phosphate, calcium phosphate, silicon oxide, titanium oxide, aluminum oxide, or zirconium oxide. The insulating coating 20a and the insulating coating 20b may both be made of the same material or different materials.

  The organic material 40 is made of, for example, a thermoplastic resin such as thermoplastic polyamide, thermoplastic polyimide, thermoplastic polyamideimide, polyethylene, polyphenylene sulfide, polyamideimide, polyethersulfone, polyetherimide, or polyetherketone. Each of the plurality of composite magnetic particles 30a and 30b is bonded by the organic material 40, or is bonded by meshing the unevenness of the composite magnetic particles 30a and 30b. In the present invention, the organic substance 40 may not be interposed between each of the plurality of composite magnetic particles 30a and 30b.

  Next, the manufacturing method of the soft magnetic material in this Embodiment is demonstrated.

  FIG. 2 is a process diagram showing the method for manufacturing the soft magnetic material in Embodiment 1 of the present invention. Referring to FIG. 2, first, for example, in the case of Fe—Si alloy, Fe—Ni alloy, Fe—Co alloy, Fe—Al alloy, or Fe—Al—Si alloy and containing Si Alloy particles 10a made of an alloy having an Si content exceeding 2.5% by mass are prepared. The average particle diameter of the alloy particles 10a is 3 μm or more and 300 μm or less.

  And the alloy particle 10a is heat-processed at the temperature of 800 degreeC or more and 1400 degrees C or less (step S1a). Numerous strains (dislocations and defects) exist in the alloy particles 10a before the heat treatment. This distortion can be reduced by performing heat treatment on the alloy particles 10a.

  Next, for example, the alloy particles 10a are immersed in an aqueous solution in which the components of the insulating coating 20a are dissolved, and then dried to form the insulating coating 20a on the surface of the alloy particles 10a (step S2a). Thereby, the composite magnetic particle 30a is obtained.

  On the other hand, for example, highly compressible soft magnetic particles 10b made of pure iron, an Fe—Si alloy having an Si content of 2.5% by mass or less, or an Fe—Al alloy having an Al content of 6% or less are prepared. The average particle size of the highly compressible soft magnetic particles 10b is set to 3 μm or more and 300 μm or less, and is equal to or less than the average particle size of the alloy particles 10a.

  Then, the highly compressible soft magnetic particles 10b are heat-treated by the same method as the alloy particles 10a (step S1b). Next, the insulating coating 20b is formed on the surface of the highly compressible soft magnetic particles 10b by the same method as that for the alloy particles 10a (step S2b). Thereby, the composite magnetic particle 30b is obtained.

  In the present embodiment, the case where the alloy particles 10a are heat-treated before the insulating coating 20a is formed is shown. However, the present invention is not limited to such a case, and the alloy particles 10a may be heat-treated after the insulating coating 20a is formed. Further, the alloy particles 10a may be heat-treated both before and after the formation of the insulating coating 20a. The same applies to the heat treatment of the highly compressible soft magnetic particles 10b.

  Next, the composite magnetic particle 30a, the composite magnetic particle 30b, and the organic substance 40 are mixed to produce a mixed powder (step S3). The ratio (content) of the composite magnetic particles 30a in the mixed powder is 65% by mass to 85% by mass, and the ratio (content) of the composite magnetic particles 30b in the mixed powder is 15% by mass to 35% by mass. The ratio (content) of the organic matter 40 in the mixed powder is 0.01% by mass or more and 0.3% by mass or less. The organic material 40 is made of, for example, a thermoplastic resin such as thermoplastic polyamide, thermoplastic polyimide, thermoplastic polyamideimide, polyethylene, polyphenylene sulfide, polyamideimide, polyethersulfone, polyetherimide, or polyetherketone.

  The mixing method is not particularly limited. For example, mechanical alloying method, vibration ball mill, planetary ball mill, mechanofusion, coprecipitation method, chemical vapor deposition method (CVD method), physical vapor deposition method (PVD method), plating Any of the method, sputtering method, vapor deposition method or sol-gel method can be used.

  In the present embodiment, the step of forming the insulating coating 20a on the surface of the alloy particle 10a (step S2a) and the step of forming the insulating coating 20b on the surface of the highly compressible soft magnetic particle 10b (step S2b) are performed. The case of performing separately is shown. Thereby, even when the average particle diameter of the alloy particles 10a and the average particle diameter of the highly compressible soft magnetic particles 10b are greatly different, a uniform insulating film can be formed on each particle. However, in the present invention, in addition to such a case, for example, after the alloy particles 10a and the highly compressible soft magnetic particles 10b are mixed, the insulating coatings 20a and 20b may be simultaneously formed on the surfaces of the respective particles. In this case, the manufacturing process can be simplified.

  Next, the obtained mixed powder is put into a mold, and pressure-molded at a pressure of, for example, 980 MPa or more (step S4). Thereby, a mixed powder is compressed and a molded object is obtained. The atmosphere for pressure molding is preferably an inert gas atmosphere or a reduced pressure atmosphere. In this case, the mixed powder can be prevented from being oxidized by oxygen in the atmosphere.

  During the pressure molding, the organic substance 40 functions as a buffer material between the composite magnetic particles 30a and 30b. This prevents the insulating coatings 20a and 20b from being destroyed by the contact between the composite magnetic particles 30a and 30b.

  Next, the molded body obtained by pressure molding is at a temperature lower than the lower one of the thermal decomposition temperature of the insulating coating 20a and the thermal decomposition temperature of the insulating coating 20b, and at a temperature of 300 ° C. or higher. Heat treatment is performed (step S5). The thermal decomposition temperature of the insulating coatings 20a and 20b is, for example, about 500 ° C. in the case of a phosphoric acid insulating coating.

  This heat treatment is carried out mainly for the purpose of eliminating the distortion generated in the molded body during pressure molding. Here, the strain that originally existed inside the alloy particles 10a and the highly compressible soft magnetic particles 10b has already been removed by the heat treatment (step S1a, step S1b) before the formation of the insulating coatings 20a, 20b. The amount of strain present inside the compact after pressure molding is relatively small. Further, this prevents the molding residual stress strain generated at the time of pressure molding from coexisting with the thermal residual stress strain originally existing in the alloy particles 10a and the highly compressible soft magnetic particles 10b. Energy will not increase. Furthermore, the distortion generated at the time of pressure molding occurs when pressure is applied from one direction to the mixed powder accommodated in the mold. For these reasons, despite the heat treatment at a relatively low temperature below the thermal decomposition temperature of the insulating coatings 20a and 20b, the distortion present in the molded body can be easily eliminated.

  In addition, since there is almost no distortion inside the alloy particles 10a and the highly compressible soft magnetic particles 10b during pressure forming, the composite magnetic particles 30a and 30b are easily deformed by pressure forming. For this reason, a molded object can be formed in the state without the gap | interval which the some composite magnetic particle 30a, 30b was mutually meshing | engaged. Thereby, the density of a molded object can be enlarged and a high magnetic flux density can be obtained. The soft magnetic material (molded body) of the present embodiment is completed through the steps described above.

According to the soft magnetic material and the manufacturing method thereof of the present embodiment, the composite magnetic particle 30a has the alloy particles 10a that are superior in magnetic properties as compared with pure iron. By setting the content of the composite magnetic particle 30a to 65% by mass or more, it is possible to obtain high AC magnetic characteristics that cannot be achieved by a soft magnetic material composed only of composite magnetic particles coated with pure iron with an insulating coating. it can. In addition, since the highly compressible soft magnetic particles 10b are excellent in formability compared to the alloy particles 10a, by setting the content of the composite magnetic particles 30b to 15% by mass or more, gaps between the plurality of composite magnetic particles 30a are formed. The composite magnetic particles 30b can be sufficiently filled. Thereby, the moldability of the soft magnetic material can be improved, and the molding density of the molded body of the soft magnetic material can be improved. As a result, a soft magnetic material having a high saturation magnetic flux density B _s can be obtained.

  Moreover, since it becomes difficult to oxidize particle | grains by making the average particle diameter of the alloy particle 10a and the highly compressible soft-magnetic particle 10b or more into 3 micrometers, the fall of the magnetic characteristic of a soft-magnetic material can be suppressed. Moreover, it can suppress that the compressibility of mixed powder falls at the time of shaping | molding because the average particle diameter of the alloy particle 10a and the highly compressible soft-magnetic particle 10b shall be 300 micrometers or less. Thereby, it can prevent that the density of the molded object obtained by the formation process does not fall, and handling becomes difficult.

  Furthermore, the surface area of the highly compressible soft magnetic particles 10b is increased by setting the average particle size of the highly compressible soft magnetic particles 10b to be equal to or less than the average particle size of the alloy particles 10a, and the content is 15% by mass or more and 35% by mass or less. Even if the amount is high, it is possible to realize a state in which the highly compressible soft magnetic particles surround the alloy particles 10a.

  According to the soft magnetic material of the present embodiment and the manufacturing method thereof, the specific density (ratio of the molding density to the true density) can be 0.80 or more, preferably 0.85 or more.

  The soft magnetic material of the present embodiment further includes an organic substance 40 having a content of 0.01% by mass to 0.3% by mass.

  Thereby, the organic substance 40 is in a state of being interposed between the highly compressible soft magnetic particles 10b and the alloy particles 10a. By setting the content of the organic matter 40 to 0.01% by mass or more, the organic matter 40 bends due to stress during pressure molding, and functions as a lubricant between the highly compressible soft magnetic particles 10b and the alloy particles 10a. . When heat treatment is performed after molding, the organic matter 40 is softened by heat and enters the gap between the alloy particles 10a and the highly compressible soft magnetic particles 10b, so that the alloy particles 10a and the highly compressible soft magnetic particles 10b. It is possible to increase the insulation between the two. On the other hand, by setting the content of the organic substance 40 to 0.3% by mass or less, the density of the magnetic part of the soft magnetic material is increased, so that the AC magnetic characteristics can be kept high.

  In the soft magnetic material of the present embodiment, the ratio of the average particle size of the highly compressible soft magnetic particles 10b to the average particle size of the alloy particles 10a is preferably 0.4 or more and 1.0 or less. Thereby, the compression moldability of the soft magnetic material is increased, and the molding density can be further improved.

  In the soft magnetic material of the present embodiment, the highly compressible soft magnetic particles 10b include pure iron, an Fe—Si alloy having an Si content of 2.5% by mass or less, and Fe—Al having an Al content of 6% or less. It contains at least one selected from the group consisting of alloys. These materials are suitable as highly compressible soft magnetic particles.

  In the method of manufacturing the soft magnetic material of the present embodiment, the alloy particles 10a are heat-treated at 800 ° C. or higher and 1400 ° C. or lower (step S1a).

  By heat-treating the alloy particles 10a at a temperature of 800 ° C. or higher, many strains (dislocations and defects) existing in the alloy particles 10a can be sufficiently eliminated, and the magnetic properties of the soft magnetic material are further improved. be able to. Moreover, it can prevent that alloy particle 10a sinters and hardens | cures by heat-processing at the temperature of 1400 degrees C or less. In the method for producing a soft magnetic material of the present invention, the sintered density was actually improved dramatically by heat-treating the alloy particles 10a at a temperature of 800 ° C. or higher.

  In the method for producing a soft magnetic material of the present embodiment, the mixed powder is pressure-molded at a pressure of 980 MPa or more to produce a molded body (step S4), and the molded body is heat-treated (step S5).

By press molding at a pressure of 980 MPa or more, the soft magnetic material can be densified. As a result, the saturation magnetic flux density B _s can be improved, and the AC magnetic characteristics can be improved. Moreover, the distortion of the alloy particles 10a caused by pressurization can be eliminated by heat-treating the compact.

  In the method of manufacturing the soft magnetic material of the present embodiment, the temperature is lower than the lower one of the thermal decomposition temperature of the insulating coating 20a and the thermal decomposition temperature of the insulating coating 20b, and is at a temperature of 300 ° C. or higher. The formed body is heat-treated (step S5).

  Thereby, the distortion of the alloy particles 10a caused by compression molding can be sufficiently eliminated while suppressing an increase in eddy current loss due to thermal decomposition of the insulating coatings 20a and 20b.

(Embodiment 2)
With reference to FIG. 1, in the first embodiment, the case where the soft magnetic material includes the organic substance 40 has been described. However, in the present invention, in addition to such a case, the soft magnetic material may include an inorganic substance instead of the organic substance 40. The ratio (content) of the inorganic substance in the soft magnetic material is 0.001% by mass or more and 0.1% by mass or less. Examples of inorganic substances include hexagonal boron nitride (h-BN), zirconium disulfide (ZrS ₂ ), vanadium disulfide (VS ₂ ), niobium disulfide (NbS ₂ ), molybdenum disulfide (MoS ₂ ), and tungsten disulfide. Sulfides such as (WS ₂ ) and rhenium disulfide (ReS ₂ ); selenides such as tungsten selenide (WSe), molybdenum selenide (MoSe) and niobium selenide (NbSe); and cadmium chloride (CdCl ₂ ) and halides such as cadmium iodide (CdI ₂ ). Such a soft magnetic material can be produced by mixing an inorganic substance instead of the organic substance 40 when the composite magnetic particle 30a and the composite magnetic particle 30b are mixed (step S3).

  Since the other soft magnetic materials and the manufacturing method thereof are substantially the same as the soft magnetic materials and the manufacturing method thereof shown in Embodiment 1, the description thereof is omitted.

  The soft magnetic material of the present embodiment further includes an inorganic substance having a content of 0.001% by mass to 0.1% by mass.

As a result, the inorganic substance is interposed between the alloy particles 10a and the highly compressible soft magnetic particles 10b. By setting the content of the inorganic substance to 0.001% by mass or more, the inorganic substance is broken along the cleavage plane under stress during pressure forming, and lubrication is performed between the alloy particles 10a and the highly compressible soft magnetic particles 10b. It plays a role in improving sex. Thus, molding density of the molded body can be further enhanced, it is possible to obtain a soft magnetic material having a high saturation magnetic flux density B _s. On the other hand, when the content of the inorganic substance is 0.1% by mass or less, it is possible to prevent the molding density from being lowered due to an excessively large proportion of the inorganic substance in the soft magnetic material.

Examples of the present invention will be described below.
Example 1
In this example, the effect of setting the content of the composite magnetic particle 30b (composite magnetic particle having a form in which the surface of the highly compressible soft magnetic particle 10b is surrounded by the insulating coating 20b) to 15% by mass or more and 35% by mass or less. Examined. Specifically, an Fe-3% Si alloy having an average particle diameter of 150 μm produced by a gas atomization method was prepared as alloy particles 10a. This alloy particle 10a was heat-treated in a hydrogen atmosphere at a temperature of 900 ° C. for 1 hour, and then an insulating coating 20a was formed by phosphorylation treatment to obtain composite magnetic particles 30a. Further, pure iron having an average particle diameter of 100 μm prepared by the gas atomization method is prepared as highly compressible soft magnetic particles 10b, and the highly compressible soft magnetic particles 10b are heat-treated at a temperature of 900 ° C. for 1 hour in a hydrogen atmosphere. An insulating coating 20b was formed by phosphorylation treatment to obtain composite magnetic particles 30b. The heat treatment temperature of the highly compressible soft magnetic particles 10b is preferably 800 ° C. or higher and 1400 ° C. or lower for the same reason as the alloy particles 10a. Next, the content of the composite magnetic particle 30b was changed, and these two types of composite magnetic particles 30a and 30b and the organic substance 40 made of 0.1% by mass of polyethylene were mixed to obtain a mixed powder. Next, this mixed powder was pressure-molded at a pressure of 1270 MPa to produce a ring-shaped dust core (molded body) having an outer diameter of 34 mm, an inner diameter of 20 mm, and a thickness of 5 mm. About the obtained powder magnetic core, the molding density and the coercive force _Hc were measured. A BH curve tracer was used to measure the coercive force. The results are shown in Table 1 and FIG.

As shown in Table 1 and FIG. 3, the molding density increases as the content of the composite magnetic particles 30b increases. When the content of the composite magnetic particles 30b is 15% by mass or more, the molding density is 7.2 g / cm ^3. The value exceeds. On the other hand, the coercive force H _c increases as the content of the composite magnetic particle 30b increases. In particular, when the content of the composite magnetic particle 30b is 40% by mass or more, the coercive force H _c is 239 A / m or more, and the magnetic properties are deteriorated. From the above results, by making the ratio of the composite magnetic particles 30b contained in the soft magnetic material and 35% or less than 15% can increase the green density, and it can be seen that reducing the coercive force H _c.

  Here, Patent Literature 1 describes that the molding density of the obtained molded body was less than 6.0. By comparing this description with this example, it can be seen that according to the manufacturing method of the present invention, a soft magnetic material having a very high molding density can be obtained. In this example, the present inventors previously removed the strain generated in the alloy particles due to the heat treatment at a temperature of 900 ° C. with respect to the high forming density exceeding 7.0 in any sample. I guess it was because of that.

(Example 2)
In this example, the effect of making the content of the organic substance 40 0.01% by mass or more and 0.3% by mass or less was examined. Specifically, composite magnetic particles 30a and 30b were prepared by the same method as in Example 1. Moreover, polyethylene (PE) was prepared as the organic substance 40. Next, the content of the composite magnetic particle 30a is about 80% by mass, the content of the composite magnetic particle 30b is about 20% by mass, and the PE content is changed between 0 to 1.00% by mass, These two types of composite magnetic particles 30a and 30b and PE were mixed to obtain a mixed powder. Thereafter, a dust core was prepared in the same manner as in Example 1, and the molding density and the magnetic flux density B ₁₀₀ were measured for the obtained dust core. The magnetic flux density B ₁₀₀ is the magnetic flux density of the dust core when a magnetic field of 8.0 × 10 ³ A / m (= 100 Oe) is applied. The measurement of the magnetic flux density B ₁₀₀ using a BH curve tracer. The results are shown in Table 2 and FIG.

As shown in Table 2 and FIG. 4, when the PE content is 0.01% by mass or more and 0.30% by mass or less, the molding density is a value exceeding 7.2 (g / cm ³ ). ing. If the content is 0.40% by mass or more, the proportion of PE becomes too large, and the molding density is lowered. When the PE content is 0.01% by mass or more and 0.30% by mass or less, the magnetic flux density B ₁₀₀ is a high value of 1.10T or more. From the above results, it can be seen that the molding density and the magnetic flux density B ₁₀₀ can be increased by setting the content of the organic substance 40 to 0.01 mass% or more and 0.30 mass% or less.

(Example 3)
In this example, the effect of making the content of the inorganic substance 0.001% by mass or more and 0.1% by mass or less was examined. Specifically, composite magnetic particles 30a and 30b were produced by the same method as in Example 1. Moreover, hexagonal boron nitride (h-BN) was prepared as an inorganic substance. Next, the content of the composite magnetic particle 30a is set to about 80% by mass, the content of the composite magnetic particle 30b is set to about 20% by mass, and the content of h-BN is changed between 0 to 0.2% by mass. Then, these two types of composite magnetic particles 30a and 30b and h-BN were mixed to obtain a mixed powder. Thereafter, a dust core was prepared in the same manner as in Example 1, and the molding density and the magnetic flux density B ₁₀₀ were measured for the obtained dust core. The results are shown in Table 3 and FIG.

As shown in Table 3 and FIG. 5, when the h-BN content is 0.001% by mass or more and 0.1% by mass or less, the molding density is 7.28 (g / cm ³ ) or more. The magnetic flux density B ₁₀₀ is a value of 1.20 (T) or more. From the above results, the content of inorganic matter by below 0.001 mass% 0.1 mass% or more, it can be seen that it is possible to enhance the molding density and the magnetic flux density B _100.

Example 4
In this example, the effect of setting the ratio of the average particle size of the highly compressible soft magnetic particles 10b to the average particle size of the alloy particles 10a to 0.4 or more and 1.0 or less was examined. Specifically, the metal magnetic particles 10b made of pure iron are sieved with 38, 50, 75, 106, 150, and 180 μm, and the average particle size is 19, 46, 62.5, 87.5, 128, It classified so that it might become 143 and 165 micrometers. Further, the alloy particles 10a made of Fe-3% Si alloy were classified so that the average particle diameter was 143 μm. Next, composite magnetic particles 30a and 30b were prepared by the same method as in Example 1 using alloy particles 10a made of Fe-3% Si alloy and metal magnetic particles 10b made of pure iron. Next, by changing the ratio of the average particle diameter of the highly compressible soft magnetic particles 10b to the average particle diameter of the alloy particles 10a in the range of 0.13 to 1.15, about 80% by mass of the composite magnetic particles 30a; About 20% by mass of the composite magnetic particle 30b and 0.1% by mass of the organic substance 40 made of polyethylene were mixed to obtain a mixed powder. Thereafter, a dust core was prepared in the same manner as in Example 1, and the molding density and the magnetic flux density B ₁₀₀ were measured for the obtained dust core. The results are shown in Table 4 and FIG.

As shown in Table 4 and Figure 6, the molding density by the ratio 0.44 or larger and 7.20 or more, and is improved becomes also 1.11 or higher value of the magnetic flux density B _100. On the other hand, it can be seen that when the ratio exceeds 1.0, the magnetic flux density B ₁₀₀ is particularly 1.10 or less, which is small. From the above results, the ratio by 0.4 to 1.0, it can be seen that it is possible to enhance the molding density and the magnetic flux density B _100.

(Example 5)
In this example, the effect of using an alloy having a Si content of 2.5% by mass or less as the highly compressible soft magnetic particles 10b was examined. Specifically, an Fe-5.5% Si alloy prepared by a gas atomization method was prepared as the alloy particle 10a, and composite magnetic particles 30a were prepared by the same method as in Example 1 (A powder). Also, pure iron, Fe-1% Si, Fe-2% Si, Fe-2.5% Si, and Fe-3 %% Si were prepared as the highly compressible soft magnetic particles 10b, and the same method as in Example 1 was prepared. Thus, composite magnetic particles 30b were produced (B powder). Next, the ratio of A powder and B powder was changed and mixed, and the powder magnetic core was produced by the method similar to Example 1. FIG. The molding density was measured for the obtained powder magnetic core. The results are shown in Table 5 and FIG. In addition, the compaction density in Table 5 and FIG. 7 is shown by the relative density when the compaction density of the powder magnetic core produced only with the powder of the Fe-5.5% Si alloy is 1.

  As shown in Table 5 and FIG. 7, when pure iron, Fe-1% Si, Fe-2% Si, and Fe-2.5% Si are used as the B powder, the mixing ratio of B powder (composite) The relative density is greatly improved when the content of the magnetic particles 30b is 15% by mass or more and 35% by mass or less. For example, when pure iron is used as the B powder, the relative density when the mixing ratio of the B powder is 10% by mass is 1.20, whereas the relative density at 15% by mass is 1.28. It has become. On the other hand, when Fe-3% Si is used as the B powder, the relative density is hardly improved regardless of the mixing ratio of the B powder (1.11 at the maximum). From the above results, it can be seen that the molding density can be increased by using an alloy having a Si content of 2.5% by mass or less as the highly compressible soft magnetic particles 10b.

  In this example, the effect of using an alloy having an Al content of 6% by mass or less as the highly compressible soft magnetic particles 10b was examined. Specifically, an Fe-5.5% Si alloy prepared by a gas atomization method was prepared as the alloy particle 10a, and composite magnetic particles 30a were prepared by the same method as in Example 1 (A powder). Further, Fe-1% Al, Fe-3% Al, Fe-5% Al, Fe-6% Al, and Fe-7% Al were prepared as the highly compressible soft magnetic particles 10b. Composite magnetic particles 30b were produced by the method (B powder). Next, the ratio of A powder and B powder was changed and mixed, and the powder magnetic core was produced by the method similar to Example 1. FIG. The molding density was measured for the obtained powder magnetic core. The results are shown in Table 5 and FIG. In addition, the compaction density in Table 5 and FIG. 8 is shown by the relative density when the compaction density of the powder magnetic core produced only with the powder of the Fe-5.5% Si alloy is 1.

  As shown in Table 5 and FIG. 8, when pure iron, Fe-1% Al, Fe-3% Al, Fe-5% Al, and Fe-6% Al were used as the B powder, The relative density is greatly improved when the mixing ratio is 15 mass% or more and 35 mass% or less. For example, when Fe-1% Al is used as the B powder, the relative density when the mixing ratio of the B powder is 10% by mass is 1.18, whereas the relative density at 15% by mass is 1. .24. On the other hand, when Fe-7% Al is used as the B powder, the relative density is hardly improved regardless of the mixing ratio of the B powder (1.03 at the maximum). From the above results, it can be seen that the molding density can be increased by using an alloy having an Al content of 6% by mass or less as the highly compressible soft magnetic particles 10b.

(Example 6)
In this example, the effect of heat-treating the alloy particles at 800 ° C. or higher and 1400 ° C. or lower was examined. Specifically, an Fe-5.5% Si alloy prepared by a gas atomization method was prepared as the alloy particle 10a, and was heat-treated at a temperature of 600 ° C. to 1400 ° C. for 1 hour in a hydrogen atmosphere, or was not subjected to heat treatment. Thereafter, a dust core was produced in the same manner as in Example 1. The mixed powder was prepared by mixing about 80% by mass of the composite magnetic particles 30a, about 20% by mass of the composite magnetic particles 30b, and an organic substance 40 made of 0.1% by mass of polyethylene. The coercive force H _c of the obtained dust core was measured. The results are shown in Table 6 and FIG.

As shown in Table 6 and FIG. 9, when the heat treatment was performed at temperatures of 600 ° C. and 700 ° C., the coercive force H _c was hardly changed as compared with the case where the heat treatment was not performed. When heat treatment is performed at a temperature of 1400 ° C. or lower, the coercive force H _c is 300 A / m or lower, which is greatly reduced. In addition, when it heat-processed at the temperature exceeding 1400 degreeC, since the alloy particle 10a will solidify, a powder magnetic core was not able to be produced. From the above results, by heat treating the alloy particles 10a at 800 ° C. or higher 1400 ° C. or less, it can be seen that it is possible to lower the coercive force H _c.

(Example 7)
In this example, the effect of heat-treating the molded body at a temperature of 300 ° C. or higher was examined. Specifically, a mixed powder is prepared by mixing about 80% by mass of the composite magnetic particle 30a, about 20% by mass of the composite magnetic particle 30b, and an organic substance 40 made of 0.1% by mass of polyethylene, A dust core was produced in the same manner as in Example 1. The heat treatment of the molded body was performed by changing in the range of 300 ° C to 500 ° C. The thermal decomposition temperature of the insulating film of the composite magnetic particles 30a and 30b was a temperature exceeding 500 ° C. About the obtained powder magnetic core, the coercive force _Hc was measured by the same method as in Example 1. The results are shown in Table 7 and FIG.

As shown in Table 7 and FIG. 10, when the heat treatment is performed at a temperature of 200 ° C., the coercive force H _c is hardly changed as compared with the case where the heat treatment is not performed. When heat treatment is performed at the following temperatures, the coercive force H _c is 300 A / m or less, which is greatly reduced. From the above results, by heat treating the compact at 300 ° C. or higher, it is understood that it is possible to lower the coercive force H _c.

  The embodiments and examples disclosed above are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments and examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims. .

  The soft magnetic material and the manufacturing method thereof according to the present invention can be used for, for example, a choke coil, a magnetic head, various motor parts, an automobile solenoid, various magnetic sensors, and various electromagnetic valves.

It is a schematic diagram which expands and shows the molded object produced using the soft-magnetic material in Embodiment 1 of this invention. It is process drawing which shows the manufacturing method of the soft-magnetic material in Embodiment 1 of this invention. In Example 1 of the present invention, showing a composite magnetic material, the relationship between the green density and the coercive force H _c with highly compressible soft particles. In Example 2 of the present invention, showing the content of the PE, the relation between the green density and the magnetic flux density B _100. In Example 3 of this invention, it is a figure which shows the relationship between content of h-BN, and a molding density. In Example 4 of this invention, it is a figure which shows the relationship between a pure iron / Fe-3% Si particle diameter ratio, and a molding density. In Example 5 of this invention, it is a figure which shows the relationship between the mixing ratio of B powder (Fe-Si alloy), and a relative density. In Example 5 of this invention, it is a figure which shows the relationship between the mixing ratio of B powder (Fe-Al alloy), and a relative density. In Example 6 of the present invention, it is a graph showing the relationship between the heat treatment temperature and the coercive force H _c of the mixed powder. In Example 7 of the present invention, it is a graph showing the relationship between the heat treatment temperature and the coercive force H _c of the molded body.

Explanation of symbols

  10a alloy particles, 10b highly compressible soft magnetic particles, 20a, 20b insulating coating, 30a, 30b composite magnetic particles, 40 organic matter.

Claims (8)

A plurality of first composite magnetic particles having alloy particles and an insulating coating surrounding the surface of the alloy particles, the content of which is 65% by mass or more and 85% by mass or less;
A plurality of second composite magnetic particles having high compressibility soft magnetic particles and an insulating coating surrounding the high compressibility soft magnetic particles, the content of which is 15% by mass or more and 35% by mass or less;
The average particle size of the alloy particles is 3 μm or more and 300 μm or less,
The soft magnetic material having an average particle diameter of 3 μm or more and 300 μm or less and an average particle diameter of the alloy particles or less.   2. The apparatus according to claim 1, further comprising at least one of an organic substance having a content of 0.01% to 0.3% by mass and an inorganic substance having a content of 0.001% to 0.1% by mass. Soft magnetic material.   The soft magnetic material according to claim 1 or 2, wherein a ratio of an average particle diameter of the highly compressible soft magnetic particles to an average particle diameter of the alloy particles is 0.4 or more and 1.0 or less.   The highly compressible soft magnetic particles are at least 1 selected from the group consisting of pure iron, an Fe—Si alloy having an Si content of 2.5% by mass or less, and an Fe—Al alloy having an Al content of 6% or less. The soft-magnetic material in any one of Claims 1-3 containing the particle | grains of a seed | species or more. Producing a plurality of first composite magnetic particles having a form in which an insulating coating is formed on the surface of the alloy particles;
Producing a plurality of second composite magnetic particles having a form in which an insulating coating is formed on the surface of the highly compressible soft magnetic particles;
Mixing for producing a mixed powder in which the first composite magnetic particles having a content of 65% by mass to 85% by mass and the second composite magnetic particles having a content of 15% by mass to 35% by mass are mixed. A powder preparation process,
The average particle size of the alloy particles is 3 μm or more and 300 μm or less,
The method for producing a soft magnetic material, wherein the highly compressible soft magnetic particles have an average particle size of 3 μm or more and 300 μm or less and an average particle size of the alloy particles or less.   The method for producing a soft magnetic material according to claim 5, further comprising an alloy particle heat treatment step of heat-treating the alloy particles at 800 ° C. or more and 1400 ° C. or less. A step of pressure-molding the mixed powder at a pressure of 980 MPa or more to produce a molded body;
The method for producing a soft magnetic material according to claim 5, further comprising a molded body heat treatment step of heat-treating the molded body.   In the compact heat treatment step, the temperature is lower than the lower one of the thermal decomposition temperature of the insulating coating of the first composite magnetic particles and the thermal decomposition temperature of the insulating coating of the second composite magnetic particles, and 300 The method for producing a soft magnetic material according to any one of claims 5 to 7, wherein the compact is heat-treated at a temperature equal to or higher than ° C.

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