JP2010236018A - High-strength low-core-loss composite soft magnetic material, method for manufacturing the same, and electromagnetic circuit parts - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite soft magnetic material of high strength and low core loss. <P>SOLUTION: A high-strength low-core-loss composite soft magnetic material is obtained by mixing a plurality of soft magnetic particles coated with an insulation film, which is formed by coating a soft magnetic particle with the insulation film, with particles of a nanomaterial powder of low-melting point glass, and a nanofiller, and compacting and firing the mixture; and includes a plurality of soft magnetic particles which are soft magnetic particles coated with the insulation film, and a boundary layer which is formed in a grain boundary between the soft magnetic particles coated with the insulation film and is formed of the low-melting point glass including the nanofiller. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a high-strength, low-loss composite soft magnetic material used as a material for various electromagnetic circuit components such as a motor, an actuator, a reactor, a transformer, a choke core, and a magnetic sensor core, a manufacturing method thereof, and an electromagnetic circuit component.

Conventionally, as magnetic core materials for motors, actuators, magnetic sensors, etc., iron powder, Fe-Al iron-based soft magnetic alloy powder, Fe-Ni iron-based soft magnetic alloy powder, Fe-Cr iron-based soft magnetic alloy powder Fe-Si-based iron-based soft magnetic alloy powder, Fe-Si-Al-based iron-based soft magnetic alloy powder, Fe-Co-based iron-based soft magnetic alloy powder, Fe-Co-V-based iron-based soft magnetic alloy powder, Fe A soft magnetic sintered material obtained by sintering -P-based iron-based soft magnetic alloy powder (hereinafter collectively referred to as soft magnetic particles) is known.
On the other hand, when iron powder or alloy powder is made by pulverization by gas or atomization method, iron powder or alloy powder alone has a low specific resistance, so the surface of iron powder or alloy powder is coated with an insulating film, Measures such as mixing organic compounds to prevent sintering and increase specific resistance are taken. In this kind of soft magnetic sintered material, in order to suppress eddy current loss, powder soft magnetic material in which the surface of metal magnetic particles containing iron is covered with a non-ferrous metal lower layer coating and an insulating film containing an inorganic compound, etc. Has been proposed.

As one means for improving the strength of this kind of soft magnetic material, Mg—Fe—O having a concentration gradient in which Mg and O decrease from the surface toward the inside and Fe increases toward the inside. Sulfur containing a higher concentration of sulfur than the sulfur contained in the center of the iron powder in the interface region with the iron powder using the Mg-containing oxide film-coated iron powder coated with the ternary oxide deposited film on the surface of the iron powder A high-strength composite soft magnetic material obtained by binding Mg-containing iron oxide film-coated iron powder having a concentrated layer with a low-melting glass phase is known. (See Patent Document 1)
As another means for improving the strength of this kind of soft magnetic material, the iron powder is formed in the interface region between the Mg—Fe—O ternary oxide deposited film containing at least (Mg, Fe) O and the iron powder. A high-strength composite soft magnetic material obtained by bonding a Mg-containing iron oxide film-coated iron powder having a sulfur-concentrated layer containing sulfur at a concentration higher than that of sulfur contained in the center portion, in a low-melting glass phase, The Mg—Fe—O ternary oxide deposited film containing (Mg, Fe) O has a fine crystal structure with a crystal grain size of 200 nm or less, and includes Mg—Fe—O containing at least (Mg, Fe) O. As the ternary oxide deposited film, a high-strength composite soft magnetic material whose outermost surface is substantially composed of MgO is known. (See Patent Document 2)

  Next, as yet another means for improving the strength of this kind of soft magnetic material, the complex or alkoxide of the elements constituting the low melting point glass on the surface of the iron powder, phosphate-coated iron powder or oxide film-coated iron powder is used. A solution film-forming iron powder, a solution film-forming phosphate-coated iron powder, or a solution film-forming oxide film-coated iron powder is prepared by applying a solution in which an organic solvent is dissolved. Low melting point glass coated iron powder, phosphate coated iron powder or oxide film coated iron by thermally decomposing organic components of solution film in formed phosphate coated iron powder or solution film formed oxide film coated iron powder After the powders are prepared, these powders are compression molded and then heat treated, or the solution film-forming iron powder, the solution film-forming phosphate-coated iron powder, or the solution film-forming oxide film-coated iron powder is compression-molded. Technique for producing a composite soft magnetic material with Chi heat treatment is known. (See Patent Document 3)

JP 2006-332525 A JP 2006-332524 A JP 2006-278833 A

  When improving the characteristics of a composite soft magnetic material using the techniques described in the above patent documents, it is manufactured by mixing raw material powder such as low-melting-point glass with insulating coated iron powder and firing it after consolidation. Even if the insulating film-coated iron powder and the low melting point glass raw material powder are uniformly mixed, the soft magnetic composite material obtained after firing has a fine particle diameter of about several tens to several hundreds of micrometers around the iron powder. Since it is difficult to form a low-melting glass layer having a uniform thickness every corner as a binder layer, it is not possible to eliminate non-uniformity particularly in terms of strength in the characteristics of the obtained composite soft magnetic material There was a problem.

  For example, when trying to obtain a soft magnetic material by a method of uniformly mixing and firing the above-mentioned iron powder and low melting point glass raw material powder, Mg formed around the refined iron powder based on the above-mentioned technique The Fe-O ternary oxide deposited film has a thickness of about 100 nm, but when a soft-magnetic material is mixed with a low-melting glass raw material powder as a binder, the low-melting glass raw material powder is obtained by a general method. Even if the powder is pulverized extremely finely, as long as it is refined by the pulverization method, the particle size is limited to about 1 μm or slightly finer than that. Mixing with iron powder with Mg-Fe-O ternary oxide deposited film, compacting and firing, the raw material components of the low melting point glass cannot evenly wrap around all the iron powder Low melting glass as a binder layer Boundary layer has a liable to become uneven.

In addition, the composite soft magnetic material manufactured using the low melting point glass raw material powder having the above-mentioned particle size is formed by forming an Mg—Fe—O ternary oxide deposited film around the refined iron powder. We try to improve the specific resistance by individually insulating the magnetic powder and reduce the eddy current loss as a composite soft magnetic material, but when we actually manufacture this composite soft magnetic material, the specific resistance is as expected. Had the problem of not improving.
As a result of extensive research by the present inventors, the Mg-Fe-O ternary oxide deposited film may be partially damaged by the low melting point glass raw material powder when the soft magnetic powder is pressed. As a result, the Mg-Fe-O ternary oxide deposited film, which should originally completely surround the iron powder, is partially damaged, and as a result, it has not been possible to secure the excellent insulating property that it should originally have. There is a problem that it is difficult to increase the eddy current loss, which tends to be disadvantageous in terms of eddy current loss.

  The present invention was devised in view of the above-mentioned problems, and its purpose is to enable compaction and firing without damaging the insulating film formed around the soft magnetic particles, and to increase the resistance. In addition, low melting point glass used as a binder is infiltrated into every corner of the soft magnetic particles and baked to produce high strength, high resistivity and low loss. An object of the present invention is to provide a high-strength, high-resistivity composite soft magnetic material capable of ensuring characteristics.

  In order to achieve the above object, the high-strength, low-loss composite soft magnetic material of the present invention comprises a plurality of insulating coated soft magnetic particles obtained by coating soft magnetic particles with an insulating film, nano raw material powder particles of low melting point glass, and nanofillers. A high-strength low-loss composite soft magnetic material obtained by mixing, compacting, and firing, a plurality of insulating coated soft magnetic particles obtained by coating soft magnetic particles with an insulating film, and these insulating coated soft magnetic materials A high-strength, low-loss composite soft magnetic material comprising a boundary layer made of low-melting glass having nanofillers formed at grain boundaries between particles.

The high-strength low-loss composite soft magnetic material of the present invention is characterized in that the insulating coating soft magnetic particles have a thickness of 5 to 200 nm.
The high-strength low-loss composite soft magnetic material of the present invention is characterized in that the average particle diameter of the soft magnetic particles is in the range of 5 to 500 μm.
The high-strength low-loss composite soft magnetic material of the present invention is characterized in that the insulating coating of the insulating coating soft magnetic particles is a Mg-containing insulating coating mainly composed of (Mg, Fe) O.
In the high-strength low-loss composite soft magnetic material of the present invention, the low-melting glass is composed of SiO2-B2O3-Na2O-based, Na2O-B2O3-ZnO-based, SiO2-B2O3-ZnO-based, SiO2-B2O3-Li2O-based glasses. It is characterized by at least one or more types.
High-strength low loss composite soft magnetic material of the present invention, the nanofiller, wherein CuO, ZnO, CoO, MgO, that comprises at least one SiO _2.
The electromagnetic circuit component of the present invention is characterized by comprising the high-strength low-loss composite soft magnetic material described above.

  The method for producing a high-strength, low-loss composite soft magnetic material of the present invention comprises mixing a plurality of insulating coated soft magnetic particles obtained by coating soft magnetic particles with an insulating film, low-melting glass nano raw material powder particles, and nanofillers. By compacting and firing, a boundary layer of low-melting glass is formed at the grain boundary between the insulating coated soft magnetic particles, and the nanofiller is left without melting.

The method for producing a high-strength, low-loss composite soft magnetic material of the present invention is characterized by using insulating coated soft magnetic particles having an Mg-containing insulating film mainly composed of (Mg, Fe) O as an insulating film.
The manufacturing method of the high-strength low-loss composite soft magnetic material of the present invention is a low melting glass of SiO2-B2O3-Na2O-based, Na2O-B2O3-ZnO-based, SiO2-B2O3-ZnO-based, SiO2-B2O3-Li2O-based glass. Of these, at least one kind is used.
The method for producing a high-strength, low-loss composite soft magnetic material of the present invention is characterized in that at least one of CuO, ZnO, CoO, MgO, and SiO ₂ is used as the nanofiller.

According to the high-strength, low-loss composite soft magnetic material of the present invention, since the insulating coating soft magnetic particles are individually covered with the insulating coating and there are few defects in the insulating coating, the individual portions in the state after consolidation firing As a result of the insulating coating of the soft magnetic particles reliably, the specific resistance can be increased in the state obtained after the consolidation firing, so that the loss can be reduced.
Since the insulating coated soft magnetic particles are bonded to each other through the boundary layer of the low melting point glass containing the nanofiller, a high-strength composite soft magnetic material having excellent mechanical coupling force at the boundary layer portion can be obtained.
Since the boundary layer is uniform and the soft magnetic particles are reliably insulated and coated, the boundary layer of the low melting point glass is brought into a high specific resistance state. The eddy current loss can be suppressed.

Further, if the insulating coating is an Mg-containing insulating film mainly composed of (Mg, Fe) O, since the Mg-containing insulating-coated soft magnetic particles are individually separated by the boundary layer having a high resistivity, the Mg containing It is possible to provide a low-strength, high-strength, low-loss composite soft magnetic material having high specific resistance and reduced eddy current loss while maintaining the excellent soft magnetic properties inherent in the insulating-coated soft magnetic particles.
Since the high-strength, low-loss composite soft magnetic material of the present invention has high density, high strength, high specific resistance, and high magnetic flux density, the composite soft magnetic material of the present invention has high strength, high magnetic flux density, and low frequency. It has the characteristics of iron loss and is excellent, and can be used as a material for various electromagnetic circuit components utilizing these characteristics.

As an electromagnetic circuit component configured using the high strength, high specific resistance, low loss composite soft magnetic material, for example, 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 or An electromagnetic circuit component that can be used as a magnetic sensor core or the like and can exhibit excellent characteristics in any case can be provided.
Electric devices incorporating these electromagnetic circuit components include motors, generators, solenoids, injectors, electromagnetically driven valves, inverters, converters, transformers, relays, magnetic sensor systems, etc. There is an effect that it contributes to performance improvement and reduction in size and weight.

FIG. 1 is a schematic diagram of a structure photograph showing an example structure of a high-strength, high-resistivity composite soft magnetic material according to the present invention. FIG. 2 is a process diagram showing an example of a process for producing a high-strength, high-resistivity composite soft magnetic material according to the present invention. FIG. 3 is a structure photograph showing a boundary layer portion made of a low melting point glass in which nanofillers are dispersed in an example structure of a high-strength low-loss composite soft magnetic material manufactured in Examples. FIG. 4 is a structure photograph showing the result of measuring the oxygen distribution state in an example structure of a high-strength low-loss composite soft magnetic material manufactured in the example. FIG. 5 is a structural photograph showing the result of measuring the distribution of Mg in an example structure of a high-strength, low-loss composite soft magnetic material manufactured in the example. FIG. 6 is a structural photograph showing the result of measuring the distribution of Fe in an example structure of a high-strength, low-loss composite soft magnetic material manufactured in the example. FIG. 7 is a structure photograph showing the result of measuring the distribution state of Cu in an example structure of a high-strength, low-loss composite soft magnetic material manufactured in Example. FIG. 8 is a structure photograph showing the results of measuring the distribution state of Zn in an example structure of a high-strength, low-loss composite soft magnetic material manufactured in Example.

  In the following, the present invention is applied in detail to an Mg-containing insulator-coated soft magnetic particle as an example. However, in the present invention, the insulating film coated on the outer surface of the soft magnetic particle is limited to an MgO insulating film. Instead, it may be a phosphate film, or a silicon oxide or aluminum oxide film obtained by adding a wet solution such as a sol-gel solution (silicate) of silica or a sol-gel solution of alumina, mixing, drying and firing.

FIG. 1 is a schematic diagram of a structure photograph showing an example structure of a high-strength, high-resistivity composite soft magnetic material according to the first embodiment of the present invention. The structure is such that Mg-containing insulator-coated soft magnetic particles 5A and 5A are bonded to each other at a boundary layer 8 made of low-melting glass in which filler 4 is dispersed.
FIG. 1 shows only a part of the structure in which two Mg-containing insulator-coated soft magnetic particles 5A are joined by a boundary layer 8 made of low-melting glass, but the actual high-strength low-loss composite soft magnetic material A is A structure structure in which a plurality of Mg-containing insulator-coated soft magnetic particles 5A are directly in contact with a portion of the structure in which the boundary layer 8 is interposed between the plurality of Mg-containing insulator-coated soft magnetic particles 5A. It is considered as a compacted body structure in which these parts are mixed.
Further, the high-strength low-loss composite soft magnetic material A in this form is substantially composed of a boundary layer 8 made of low-melting glass in which nanofillers 4 existing between the Mg-containing insulator-coated soft magnetic particles 5A and 5A are dispersed. All the Mg-containing insulator-coated soft magnetic particles are dispersed as uniformly as possible, and the high-strength and low-loss composite soft softening with high strength and low loss is achieved by uniform dispersion of the boundary layer 8 in which the nanofiller 4 is dispersed. Magnetic material A is obtained. In the boundary layer 8, the nanofillers 4 are present alone or distributed over a wide area in a state where they are aggregated.

In the high-strength low-loss composite soft magnetic material A of this form, the Mg-containing insulating coating 6 existing on the surface of the Mg-containing insulator-coated soft magnetic particle main body 5 is sufficiently adhered to the soft magnetic particles, and the Mg-containing insulation Object-coated soft magnetic particles 5A are formed.
With such a structure, a large number of Mg-containing insulator-coated soft magnetic particle bodies 5 are insulatively coated with a sufficient amount of Mg-containing insulating film 6, and they are made of low-melting-point glass in which nanofillers 4 are dispersed. It is joined through the boundary layer 8 or has a structure in which Mg-containing insulator-coated soft magnetic particles 5A are joined together. The nanofiller 4, the Mg-containing insulator-coated soft magnetic particle body 5, the Mg-containing insulating film 6, and the grain boundary layer 8 in which the nanofiller 4 is dispersed will be described in detail later.

Hereinafter, an example of a method for producing the high-strength low-loss composite soft magnetic material A having the structure shown in FIG.
"Production of Mg-containing insulator-coated soft magnetic particles"
In the present invention, first, Mg-containing insulator-coated soft magnetic particles (powder) in which a Mg—Fe—O ternary oxide deposition film containing (Mg, Fe) O is coated on the surface of the soft magnetic particles are produced. .
In order to obtain the coated soft magnetic particles, any of the following raw material powders may be used and the method described later may be used.
Fe-based soft magnetic particles as raw material powder used in the method for producing Mg-containing insulator-coated soft magnetic particles of the present invention are conventionally known iron powder, Fe-Al based iron-based soft magnetic alloy powder, Fe -Ni-based iron-based soft magnetic alloy powder, Fe-Cr-based iron-based soft magnetic alloy powder, Fe-Si-based iron-based soft magnetic alloy powder, Fe-Si-Al-based iron-based soft magnetic alloy powder, Fe-Co-based iron A base soft magnetic alloy powder, an Fe—Co—V iron-based soft magnetic alloy powder, or an Fe—P iron-based soft magnetic alloy powder is preferable.
More specifically, the iron powder is pure iron powder, the Fe—Al-based iron-based soft magnetic alloy powder contains Al: 0.1 to 20% by mass, and the balance is Fe—Al composed of Fe and inevitable impurities. It is preferable to be an iron-based soft magnetic alloy powder (for example, an alpalm powder having a composition composed of Fe-15 mass% Al).

Further, the Fe—Ni-based iron-based soft magnetic alloy powder contains Ni: 35 to 85% by mass, and Mo: 5% by mass or less, Cu: 5% by mass or less, Cr: 2% by mass or less, and Mn as required. : A nickel-based soft magnetic alloy powder (for example, Fe-49 mass% Ni powder) containing one or more of 0.5 mass% or less, with the balance being Fe and inevitable impurities, Fe— Cr-based iron-based soft magnetic alloy powder contains Cr: 1 to 20% by mass, and optionally contains one or two of Al: 5% by mass or less, Ni: 5% by mass or less, and the balance Is an Fe—Cr-based iron-based soft magnetic alloy powder composed of Fe and inevitable impurities, and the Fe—Si-based iron-based soft magnetic alloy powder contains Si: 0.1 to 10% by mass, with the balance being Fe and inevitable Preferably, the Fe-Si iron-based soft magnetic alloy powder is made of impurities. Arbitrariness.
The Fe—Si—Al-based iron-based soft magnetic alloy powder contains Si: 0.1 to 10% by mass, Al: 0.1 to 20% by mass, and the balance is Fe—Si composed of Fe and inevitable impurities. -Al-based iron-based soft magnetic alloy powder, Fe-Co-V-based iron-based soft magnetic alloy powder contains Co: 0.1 to 52 mass%, V: 0.1 to 3 mass%, the balance Is an Fe—Co—V-based iron-based soft magnetic alloy powder comprising Fe and inevitable impurities, and the Fe—Co-based iron-based soft magnetic alloy powder contains 0.1% to 52% by mass of Co, with the balance being Fe. And Fe—Co-based iron-based soft magnetic alloy powder composed of inevitable impurities, Fe—P-based iron-based soft magnetic alloy powder contains P: 0.5 to 1% by mass, and the balance is Fe and inevitable impurities. The Fe-P-based iron-based soft magnetic alloy powder is preferable.

  The Fe-based soft magnetic particles are preferably soft magnetic alloy powders (particles) having an average particle size in the range of 5 to 500 μm. The reason is that if the average particle size is less than 5 μm, the compressibility of the soft magnetic particles is lowered, and the volume ratio of the soft magnetic particles is lowered, so that the value of the magnetic flux density is lowered. If the diameter is larger than 500 μm, the eddy current inside the soft magnetic particles increases and the magnetic permeability at high frequency decreases.

Using any one of these various Fe-based soft magnetic particles as a raw material powder, and after subjecting it to an oxidation treatment of keeping at room temperature to 500 ° C. in an oxidizing atmosphere, Mg powder was added to this raw material powder and mixed. The mixed powder is heated in an inert gas atmosphere or a vacuum atmosphere at a temperature of 150 to 1100 ° C. and a pressure of 1 × 10 ⁻¹² to 1 × 10 ⁻¹ MPa, and further in an oxidizing atmosphere, if necessary, a temperature of 50 to 50 When heated at 400 ° C., Mg-containing insulator-coated soft magnetic powder (particles) 5A having the Mg-containing oxide insulating film 6 on the surface of the Fe-based soft magnetic particles is obtained.
The addition amount of the Mg powder is preferably in the range of 0.1 to 0.3% by mass, the heating temperature is 650 ° C., and the vacuum atmosphere is pressure: 1 × 10 ⁻⁷ to 1 × 10 ⁻⁴ MPa The vacuum atmosphere is preferable.
This Mg-containing insulator-coated soft magnetic particle 5A has much better adhesion than the conventional Mg-containing insulator-coated soft magnetic particle on which an Mg ferrite film is formed. Even if a green compact is produced by press molding 5A, the insulating film is less likely to break and peel off, and the green compact of this Mg-containing insulator-coated soft magnetic particle 5A is fired at a temperature of 400 to 1300 ° C. The soft magnetic composite compacted fired material obtained in this way has a structure in which the Mg-containing oxide film is uniformly dispersed at the grain boundaries and the Mg-containing oxide film is not concentrated at the grain boundary triple points.

In the case of the manufacturing method described above, oxidized soft magnetic particles are used as raw material powder, and mixed powder obtained by adding and mixing Mg powder to this raw material powder is temperature: 150-1100 ° C., pressure: 1 × 10 ^−12. In order to heat in an inert gas atmosphere or vacuum atmosphere of ˜1 × 10 ⁻¹ MPa, it is preferable to heat the mixed powder while rolling.

The term “deposited film” usually indicates a film in which atoms constituting a film deposited by vacuum evaporation or sputtering are deposited on a substrate, for example. The deposited film used in the present invention is an Fe-based soft magnetic film having an iron oxide film. 3 shows an Mg-containing insulating film deposited on the surface of the Fe-based soft magnetic particles with the reaction of particles of iron oxide (Fe—O) and Mg. The film thickness of the Mg-containing insulating film (Mg—Fe—O ternary oxide deposition film) formed on the surface of the Fe-based soft magnetic particles is equal to the high magnetic flux density of the soft magnetic composite compacted fired material after compacting. In order to obtain a high specific resistance, it is preferably in the range of 5 nm to 200 nm.
If the film thickness is less than 5 nm, the specific resistance of the compacted soft magnetic composite compacted fired material tends to be insufficient, and eddy current loss increases, which is not preferable, and the film thickness exceeds 200 nm. Then, the magnetic flux density of the soft magnetic composite compacted fired material that has been compacted tends to decrease. A preferable film thickness in such a range is in the range of 5 nm to 100 nm.

"Method of manufacturing high-strength, low-loss composite soft magnetic material"
In order to produce a high-strength low-loss composite soft magnetic material using the Mg-containing insulator-coated soft magnetic particles prepared as described above by the method described above, first, the Mg-containing insulator-coated soft magnetic material prepared by the method described above is used. A raw material powder (particles) of a low melting glass as a binder material is added to the magnetic particles, and a nano filler as a dispersion is added.
The raw material mixed powder (particles) of the low-melting glass is preferably a raw material powder having a nano order, particularly an average particle size of about 2 to 200 nm, and more preferably an average particle size of 2 to 100 nm. Moreover, the addition amount of the raw material mixed powder of the low melting glass is preferably in the range of 0.1 to 5% by mass with respect to the mass of the Mg-containing insulator-coated soft magnetic particles.
Nanofillers, CuO, ZnO, become CoO, MgO, an inorganic particles such as SiO _2, the average particle diameter is preferably in the range of 2 to 200 nm, range of 2~100nm is more preferable. The addition amount of the nanofiller is preferably in the range of 0.1 to 0.4% by mass with respect to the mass of the Mg-containing insulator-coated soft magnetic particles. If too much nanofiller is added, the bonding force connecting the Mg-containing insulator-coated soft magnetic particles at the grain boundary tends to be weakened.
In addition, since it is not easy to handle the raw material powder and nanofiller in these particle size ranges, when adding to the Mg-containing insulator-coated soft magnetic particles, the raw material powder and nanofiller are added to an organic solvent such as ethanol. It is preferable to adopt a method of uniformly dispersing by ultrasonic dispersion, immersing the Mg-containing insulator-coated soft magnetic particles in this organic solvent, taking out, removing the organic solvent by drying, and molding. However, a method of mixing the raw material powder and the above-mentioned Mg-containing insulator-coated soft magnetic particles by a dry method and molding them is also possible.

As the low melting point glass used here, it is preferable to use at least one of SiO 2 -B 2 O 3 -Na 2 O, Na 2 O—B 2 O 3 —ZnO, SiO 2 —B 2 O 3 —ZnO, and SiO 2 —B 2 O 3 —Li 2 O glasses.
If necessary, SiO2 in these low-melting glass, Na2O, ZnO, B2O3, Li2O , SnO, BaO, a low-melting glass having a composition with the addition of one or more kinds of CaO, Al2 O3, _{K 2} O May be used.
For example, it can be exemplified such as SiO2-B2O3-ZnO system the added composition system of Al2O3 and Li2O, the composition system with the addition of SnO BaO, CaO and Al2O3, _{K 2} O in the SiO2-B2O3-ZnO system.

As more specific composition examples, (A1) SiO2: 15% by mass, ZnO: 31% by mass, B2O3: 48% by mass, Al2O3: 4% by mass, Li2O: 2% by mass, (A2) SiO2: 10 -25 mass%, Na2O: 5-10 mass%, ZnO: 30-40 mass%, B2O3: 40-50 mass% composition example, (A3) SiO2 + Na2O: 45 mass% or less, ZnO: 20-30 mass%, Composition example of BaO: 1 to 10 mass%, B2O3: 20 to 30 mass%, Al2O3: 1 to 10 mass% (A4) SiO2: 5 to 25 mass%, SnO: 1 to 10 mass%, ZnO: 30 to 55 wt%, BaO: 1-10 wt%, CaO: 1 to 10 wt%, B2 O3: 20 to 30 wt%, Al2 O3: 1 to 10 _mass%, K 2 O: illustrated and 1 to 10 mass% of the composition example To do Kill.
Next, the high-strength and low-loss composite soft magnetic material is obtained by firing the molded body in a non-oxidizing atmosphere such as a nitrogen atmosphere, preferably at 300 ° C. to 1000 ° C., for example, 650 ° C. for several tens of minutes, for example, about 30 minutes. Form.

FIG. 2 shows an example of the order of steps from the first step for preparing the raw material to the final processing in the case of manufacturing the Mg-containing insulator-coated soft magnetic material. In step S1 of FIG. The raw material of the soft magnetic alloy powder (for example, pure iron powder) as the prepared raw material is pre-oxidized and surface oxidized in step S2, Mg is vapor-deposited in step S3, and low melting point glass raw material powder (particles separately prepared in step S4) ) After mixing with 1 and nanofiller 2, it is dried in step S5, formed into the desired shape in step S6, and fired in step S7, so that the high-strength low-loss composite according to the present invention as described above A soft magnetic material can be obtained.
In step S4 in which the above mixing is performed, as an example, the low-melting glass raw material mixed powder 1 and the nanofiller 2 are uniformly dispersed in ethanol by applying ultrasonic vibration in an organic solvent such as ethanol. Insulating coated soft magnetic particles in which the above Mg—Fe—O ternary oxide deposited film is formed in this organic solvent may be introduced and dried in the subsequent step S5. Alternatively, the Mg—Fe— The insulating coating soft magnetic particles on which the O ternary oxide deposited film is formed, the low melting glass raw material mixed powder 1 and the nanofiller 2 may be directly mixed. In addition, when employ | adopting the method of mixing directly by such a dry type, the process of heating and drying of process S5 is unnecessary.
The various conditions to be selected in the above-described steps S1 to S7 are preferably the conditions described above or the conditions described later.

When the Mg-containing insulator-coated soft magnetic particles and the low-melting-point glass raw material mixed powder and nanofiller existing around the Mg-containing insulator-coated soft magnetic particles in the above-described step S6 are compacted using a mold or the like, a molded body having a desired shape can be obtained. it can. The thickness of the Mg—Fe—O ternary oxide deposited film is 5 nm to 200 nm for the purpose of preventing damage to the Mg-containing insulating film (Mg—Fe—O ternary oxide deposited film) as much as possible during consolidation. When the raw material powder (particles) of the low-melting glass is about 2 to 200 nm and the nanofiller is about 2 to 200 nm, the Mg—Fe—O ternary oxide It is preferable to make the particle size of the raw material mixed powder of the low melting point glass and the nano filler smaller than the film thickness of the deposited film.
This is because the raw material mixed powder of the low melting point glass is inevitably pressed against the Mg—Fe—O ternary oxide deposited film during consolidation, so that the Mg—Fe—O ternary oxide deposited film physically This is to reduce the damage to the surface. If a low melting glass raw material powder or nanofiller larger than the film thickness of the Mg-Fe-O ternary oxide deposited film is removed from this relationship, the Mg-Fe-O ternary oxide deposited film is damaged during consolidation. As a result, the soft magnetic particles come into contact with each other at the damaged site to cause conduction, so that the specific resistance value of the finally obtained composite soft magnetic material is lowered. Further, even if it is attempted to prepare a low melting point glass raw material powder having a thickness smaller than that of the Mg—Fe—O ternary oxide deposited film by deviating from this relationship, the powder particle size becomes too small, which hinders handling during production. There is a high risk of coming.

The high-strength, low-loss composite soft magnetic material A obtained by the method described above has a combination of the plurality of Mg-containing insulator-coated soft magnetic particles 5A so that the soft magnetic particle main body 5 and the surface of the soft magnetic particle main body 5 The Mg-containing insulator-coated soft magnetic particles 5A including the Mg-containing insulating film (Mg-containing oxide film) 6 coated on the nano-order low-melting-point glass raw material mixture described above It is a material obtained by mixing the powder and the nanofiller, compacting and firing, and thereby obtaining the boundary layer 8 composed of the low melting point glass layer in which the nanofiller is dispersed, and the soft magnetic particle body 5 with the Mg-containing insulating film 6 Is sufficiently covered, a high specific resistance can be obtained.
Therefore, for example, as shown in FIG. 1, the boundary layer 8 made of low-melting glass containing nanofillers 4 existing between the Mg-containing insulator-coated soft magnetic particles 5A and 5A has substantially all of the Mg-containing insulator-coated soft magnetic particles 5A and 5A. Since the boundary layer 8 is dispersed as uniformly as possible between the magnetic particles, and the Mg-containing insulating coating 6 exists on the surface of each Mg-containing insulator-coated soft magnetic particle body 5 in a necessary and sufficient thickness, High strength, high specific resistance and low loss are obtained. This is because when the nano-order fine low melting point glass raw material mixed powder 7 is softened or melted, each element easily flows around the Mg-containing insulator-coated soft magnetic particles, the composition ratio is uniform, and This is because the boundary layer 8 in which the nanofiller 4 is uniformly dispersed is formed, and the low melting point glass raw material mixed powder having a sufficiently small particle size with respect to the thickness of the Mg—Fe—O ternary oxide deposited film and This is because the use of the nanofiller causes less damage to the Mg—Fe—O ternary oxide deposited film during consolidation and covers the soft magnetic particle body 5 with a sufficient film thickness.

  In addition, by adding nanofillers, when the low melting point glass is softened or melted during firing after compacting, the nanofiller enters between the insulating films, so that the insulating coating-coated soft magnetic particles approach each other. Contact can be prevented. As a result, the insulating coating is damaged, so that it is possible to prevent a decrease in specific resistance caused by conduction caused by the contact of the soft magnetic particles at the damaged site, and to achieve both high strength and compatibility.

Moreover, the high-strength low-loss composite soft magnetic material obtained by the above manufacturing method has high density, high strength, high specific resistance, low loss, and high magnetic flux density. Since it has the characteristics of high magnetic flux density and high frequency and low iron loss, it can be used as a material for various electromagnetic circuit components utilizing this characteristic.
Further, in the high-strength low-loss composite soft magnetic material obtained by the above manufacturing method, the Mg-Fe-O ternary oxide deposited film containing (Mg, Fe) O exists at the interface thereof. Since it has a boundary layer with excellent uniformity of low melting point glass containing nanofillers, especially the Mg-containing insulator-coated soft magnetic particles are well-bonded, and the individual insulation coating of the particles is sufficient. Therefore, it is possible to obtain a high-strength, low-loss composite soft magnetic material having high strength, high specific resistance, low eddy current loss, and excellent soft magnetic characteristics with low iron loss.

  The insulating film to be coated on the surface of the soft magnetic particles is not limited to the Mg-Fe-O ternary oxide deposited film, but may be a phosphate film, a silicon oxide film, an aluminum oxide film, etc. Well, by setting the desired film thickness as described above, it is possible to reduce damage to the insulating film at the time of mixing and compacting with a low melting point glass raw material mixed powder having a sufficiently small particle diameter, and an equivalent effect can be obtained.

Heat treatment was performed for 0 to 60 minutes at 250 ° C. in the air on soft magnetic particles (pure iron powder) having an average particle size of 100 μm. Here, since the MgO film is proportional to the oxide film thickness generated by the heat treatment at 250 ° C. in the previous stage, the addition amount of Mg may be the minimum necessary, and 0.3% by mass of Mg powder with respect to the iron powder. The blended powder was heated to 650 ° C. while being rolled by a batch rotary kiln in a vacuum atmosphere of 0.1 Pa, so that the Mg—Fe—O ternary oxide deposited film-coated soft magnetic particles (Mg containing Insulator-coated soft magnetic particles) were prepared.
The film thickness of the Mg—Fe—O ternary oxide deposited film containing (Mg, Fe) O formed on the outer peripheral surface of the Mg-containing insulator-coated soft magnetic particle is generated by the above-described heat treatment in the atmosphere. Since the film thickness is proportional to the oxide film thickness, a film having a film thickness of 20 to 200 nm was used as a test sample.

Next, it is each composition ratio shown in Table 2, Comprising: Using the raw material powder samples 1-6 for low melting glass of each average particle diameter shown in Table 1, these raw material powders are used suitably, CuO filler (average particle size) 48 nm) or ZnO filler (average particle diameter 30 nm) and mixed with Mg-containing insulator-coated soft magnetic particles at a rate of 10 g / cm ^{3 in} ethanol, and uniformly dispersed by an ultrasonic vibrator, By heating and evaporating ethanol, a mixed powder was obtained in which the raw material powder of the low melting point glass and the CuO filler or ZnO filler having the above composition ratios were adhered to the surface of the Mg-containing insulator-coated soft magnetic particles.
Next, it compacted with the shaping | molding pressure shown in Table 1, and baked at 650 degreeC in nitrogen atmosphere for 0.5 hour as shown in Table 3, and obtained the target soft-magnetic composite compacted fired material.
Fracture strength (MPa), specific resistance (μΩ · m), density (Mg / m ³ ), magnetic flux density at 10 kA / m (T), 1.0 T · Table 3 shows the results of measuring the core loss (W / kg) value at 400 Hz.

"Comparative example"
For comparison, the composition ratios shown in Table 2 were mixed with CuO filler or ZnO filler using the raw material powder samples 7 to 12 for low melting point glass having the average particle diameter shown in Table 1 as appropriate. Mg-containing insulator coating Soft magnetic particles and 10 g / cm ^{3 in} ethanol, uniformly dispersed by an ultrasonic vibrator, and heated to evaporate ethanol, Mg-containing insulator coating A mixed powder was obtained in which the raw material powder of the low melting point glass having the above-described composition ratio was adhered to the surface of the soft magnetic particles.
Next, it compacted with the shaping | molding pressure shown in Table 1, and baked at 650 degreeC in nitrogen atmosphere for 0.5 hour as shown in Table 3, and obtained the target soft-magnetic composite compacted fired material.

"Conventional example"
The Mg-containing insulator-coated soft magnetic particles are compacted at a molding pressure of 790 MPa, and fired at 650 ° C. for 0.5 hours in a nitrogen atmosphere as shown in Table 3. A magnetic composite compacted fired material was obtained.
Fracture strength (MPa), specific resistance (μΩ · m), density (Mg / m ³ ), magnetic flux density at 10 kA / m (T) of each sample of the soft magnetic composite compacted fired material obtained in the conventional example and the comparative example ) The results of measuring the core loss (W / kg) value at 1T · 400 Hz are shown in Table 3.

  Next, with respect to the sample No. 3 in Table 3, FIG. 3 shows a structure photograph in which the cross-section of two adjacent Mg-containing insulator-coated soft magnetic particles and the boundary layer portion existing between them is shown. In the structure photograph of FIG. 3, a groove-like portion extending from the upper left diagonal direction to the lower right diagonal side indicates the boundary layer. Further, as shown in FIG. 3, it was confirmed that the non-melted nanofiller was dispersed inside the boundary layer.

  From the results shown in Table 3, the high bending strength is higher than that of the conventional example and the comparative example, the specific resistance is high, the density is the same or slightly higher, the magnetic flux density is the same or slightly higher, and the excellent high strength and high ratio with less iron loss. It was found that a low resistance loss composite soft magnetic material can be obtained. Further, the preferred range of the particle size of the raw powder of the low melting point glass is in the range of 5 to 200 nm. Specifically, good characteristics are obtained in the range of 19 to 135 nm, and the more preferred range is in the range of 5 to 100 nm. However, in the specific range of 19 to 31 nm, it was found that the specific resistance was higher and the iron loss was smaller.

In Table 3, the samples No. 7 to No. 12 are all large samples in which the average particle size of the low-melting glass raw material powder exceeds 200 nm. The specific resistance of the samples Nos. 7 to 12 was much smaller than that of the example sample, the numerical value of the iron loss was greatly increased, and the characteristics were deteriorated. In addition, the bending strength of the sample of the conventional example is remarkably deteriorated, and although the specific resistance is slightly higher than that of the sample of the comparative example, the specific resistance is much lower than that of the sample of the example, and the iron loss is greatly increased. It is getting worse.
From the comparison shown in Table 3, the samples No. 1 to 6 according to the present invention have a high bending strength, a high specific resistance value, a low iron loss, a high density, and a soft magnetic property indicated by a magnetic flux density. Was also found to be excellent.
In addition, according to the samples Nos. 13 to 15 in Table 1, the addition amount of the nano filler is desirably in the range of 0.1 to 0.4% by mass with respect to the mass of the Mg-containing insulator-coated soft magnetic particles, Outside this range, if the addition amount is small, there is a problem of reducing the effect of preventing the contact between the Mg—Fe—O ternary oxide deposited films containing (Mg, Fe) O by the filler during compaction molding. When the amount added is large, the grain boundary between the Mg-containing insulator-coated soft magnetic particles after compaction forming becomes wider, and the glass layer hardened after firing tends to have more voids, which tends to decrease both density and strength. There is.
Furthermore, when the addition amount of the nanofiller is remarkably small with respect to the low-melting glass, it approaches the characteristics of the structure in which only the low-melting glass is added.

Next, FIGS. 4 to 8 show the results of elemental analysis of the sample shown in FIG. 4 is a distribution diagram of O (oxygen), FIG. 5 is a distribution diagram of Mg (magnesium), FIG. 6 is a distribution diagram of Fe (iron), FIG. 7 is a distribution diagram of Cu (copper), and FIG. It is a distribution map of Zn (zinc) in the sample of No.3.
From these figures, the presence of Fe in the boundary layer is small, O and Zn derived from the main components of the low-melting glass, and Cu and Mg—Fe—O ternary oxide deposits derived from the filler components. It was confirmed that Mg derived from the main component of the film was present in the boundary layer, a low-melting glass was reliably generated in the boundary layer, and a large number of nanofillers were aggregated and distributed over a wide area. . Further, from the distribution state of FIG. 7 showing the distribution of Cu, a large number of CuO nanofillers are present in the boundary layer of the low-melting-point glass alone or aggregated (a plurality of gray particles existing in the grain boundary layer of FIG. 7). Part) was confirmed.
Moreover, it has confirmed that the glass layer existed in the grain boundary between soft-magnetic particles from the distribution state of FIG. 8 which shows distribution of Zn in a low melting glass component.

The high-strength, high-resistivity, low-loss composite soft magnetic material according to the present invention includes, for example, a magnetic core, an electric motor core, a generator core, a solenoid core, an ignition core, a reactor core, a transformer core, a choke coil core, or a magnetic sensor core. And can be applied to electromagnetic circuit components that can exhibit excellent characteristics.
Electric devices incorporating these electromagnetic circuit components include motors, generators, solenoids, injectors, electromagnetically driven valves, inverters, converters, transformers, relays, magnetic sensor systems, etc. Increase performance and reduce size and weight.

  A ... high strength high specific resistance composite soft magnetic material, 4 ... nano filler, 5 ... Mg-containing insulator-coated soft magnetic particle body, 5A ... Mg-containing insulator-coated soft magnetic particle, 6 ... Mg-containing insulating film (Mg-Fe -O ternary oxide deposited film), 8 ... boundary layer.

Claims (11)

  High-intensity low-loss composite soft magnetism obtained by mixing, sintering and firing a mixture of soft magnetic particles coated with a soft magnetic particle, a plurality of insulating coated soft magnetic particles, low-melting glass nano raw material powder particles, and nanofillers Boundary made of a low-melting glass comprising a plurality of insulating coated soft magnetic particles formed by coating soft magnetic particles with an insulating coating, and a nanofiller formed at a grain boundary between the insulating coated soft magnetic particles. A high-strength, low-loss composite soft magnetic material characterized by comprising a layer.   2. The high-strength low-loss composite soft magnetic material according to claim 1, wherein a thickness of the insulating coating of the insulating coating soft magnetic particles is in a range of 5 to 200 nm.   3. The high-strength, low-loss composite soft magnetic material according to claim 1, wherein an average particle diameter of the soft magnetic particles is in a range of 5 to 500 μm.   The high-strength, low-loss composite according to any one of claims 1 to 3, wherein the insulating coating of the insulating coating soft magnetic particles is an Mg-containing insulating coating mainly composed of (Mg, Fe) O. Soft magnetic material.   The low-melting glass is at least one of SiO2-B2O3-Na2O-based, Na2O-B2O3-ZnO-based, SiO2-B2O3-ZnO-based, and SiO2-B2O3-Li2O-based glasses. The high-strength low-loss composite soft magnetic material according to any one of 1 to 4. The nanofiller, CuO, ZnO, CoO, MgO , high strength low loss composite soft magnetic material according to claim 1, characterized in that it consists of at least one of SiO _2.   An electromagnetic circuit component comprising the high-strength low-loss composite soft magnetic material according to any one of claims 1 to 6.   Grain boundaries between insulating coated soft magnetic particles by mixing a plurality of insulating coated soft magnetic particles formed by coating soft magnetic particles with an insulating film, raw powder particles of low-melting glass, and nanofillers, and compacting and firing. In addition, a method for producing a high-strength low-loss composite soft magnetic material is characterized in that a boundary layer of low-melting glass is formed and the nanofiller is left without melting.   9. The method for producing a high-strength, low-loss composite soft magnetic material according to claim 8, wherein the insulating coated soft magnetic particles having an Mg-containing insulating film mainly composed of (Mg, Fe) O are used as the insulating film.   8. The low melting point glass is characterized by using at least one of SiO2-B2O3-Na2O-based, Na2O-B2O3-ZnO-based, SiO2-B2O3-ZnO-based, and SiO2-B2O3-Li2O-based glasses. Or 9. A method for producing a high-strength, low-loss composite soft magnetic material according to 8. 11. The high-strength low-loss composite soft magnetic material according to claim 8, wherein at least one of CuO, ZnO, CoO, MgO, and SiO ₂ is used as the nanofiller.