WO2022070786A1 - Noyau aggloméré - Google Patents

Noyau aggloméré Download PDF

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Publication number
WO2022070786A1
WO2022070786A1 PCT/JP2021/032619 JP2021032619W WO2022070786A1 WO 2022070786 A1 WO2022070786 A1 WO 2022070786A1 JP 2021032619 W JP2021032619 W JP 2021032619W WO 2022070786 A1 WO2022070786 A1 WO 2022070786A1
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Prior art keywords
soft magnetic
dust core
powder
insulating layer
core
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PCT/JP2021/032619
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English (en)
Japanese (ja)
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哲隆 加古
英一郎 島津
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Ntn株式会社
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Publication of WO2022070786A1 publication Critical patent/WO2022070786A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/16—Metallic particles coated with a non-metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147—Alloys characterised by their composition
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/20—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/22—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H01F1/24—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H01F27/255—Magnetic cores made from particles

Definitions

  • the present invention relates to a dust core.
  • the dust core is manufactured by covering the surface of the soft magnetic powder with an insulating film and compression-molding the soft magnetic powder with the insulating film.
  • Typical examples of dust core applications include DC-DC converters, inverters, transformers used in switching power supplies, and noise-cutting choke coils.
  • the inductor (chip inductor) mounted on the board of the power supply circuit is often used in the high frequency range of several hundred kHz to several MHz. Therefore, the powder magnetic core also needs a material composition suitable for use in a high frequency range. The higher the frequency, the greater the loss (iron loss) that is absorbed by the dust core and becomes heat. Since most of this loss is caused by the eddy current loss, how to reduce the eddy current loss is an important issue in examining the material and composition of the dust core.
  • the dust core for chip inductors is required to have high volume resistivity and high magnetic permeability.
  • a dust core for a chip inductor As described in Patent Document 1, a molded body of Fe—Cr—Al-based soft magnetic powder is heat-treated in an oxidizing atmosphere.
  • a magnetic field is generated by applying a high frequency current to the induction heating coil, and the work is heated by generating an induced current.
  • the iron core in the central portion or the peripheral portion of the exciting coil, the generated magnetic flux density can be increased and the heating efficiency can be improved.
  • Laminated steel sheets, ferrite, etc. are generally used as the iron core material, but in recent years, in order to suppress iron loss and improve efficiency, it has been considered to use a dust core using soft magnetic powder as the iron core. Has been done.
  • high-frequency induction heating devices are often used in the high-frequency range of 100 kHz or higher, so how to avoid eddy current loss in the high-frequency range even with a dust core for high-frequency induction heating devices.
  • a dust core for high-frequency induction heating devices It has become an important issue in examining the material and composition of the dust core.
  • a powder magnetic core for a high-frequency induction heating device is required to have high volume resistivity and high strength.
  • Patent Document 2 As a dust core for a high-frequency induction heating device, as described in Patent Document 2, an iron-based soft magnetic material powder integrated with an insulating film made of an epoxy resin is known.
  • the insulating layer inside the dust core for a relatively thick powder core of 10 mm or more. There is also the problem that it is difficult to form.
  • the magnetic core for the induction hardening device described in Patent Document 2 uses a mixture of epoxy resin and iron powder, there is a problem that the powder magnetic core tends to deteriorate during continuous use.
  • an object of the present invention is to provide a dust core with improved frequency characteristics while ensuring the necessary insulation.
  • the dust core according to the present invention has soft magnetic particles and an insulating layer formed on the surface of the soft magnetic particles.
  • the soft magnetic particles contain an alloy element containing either or both of Si and Cr, and the total content of the alloy element in the soft magnetic particles is 2.0 mass% or more. , 7.0 mass% or less (preferably 6.5 mass% or less), the insulating layer contains SiO 2 as a main component, and the thickness of the insulating layer is 0.05 ⁇ m to 0.6 ⁇ m. ..
  • the soft magnetic particles contain an alloy element containing either one or both of Si and Cr, and the total content of the alloy elements in the soft magnetic particles is 2.0 mass% or more and 7.0 mass% or less.
  • the content of the alloying element is reduced, so that it is possible to avoid a decrease in the relative magnetic permeability due to a decrease in compressibility.
  • SiO 2 as a main component of the insulating layer and setting the thickness of the insulating layer to 0.05 ⁇ m to 0.6 ⁇ m, it is possible to obtain high insulating properties while suppressing a decrease in the specific magnetic permeability.
  • the insulating layer containing SiO 2 as a main component is obtained by heating a substance containing Si and O (silane coupling agent, silicone oligomer, silicone resin, etc.) with magnetic annealing, it relies on atmospheric gas. It is possible to form an insulating layer without the need for silicon. Therefore, oxygen does not need to enter when forming the insulating layer, and it is possible to form the insulating layer even inside a thick dust core.
  • Si and O silane coupling agent, silicone oligomer, silicone resin, etc.
  • the volume resistivity of the dust core is preferably 1 ⁇ 10 6 ⁇ cm or more. As a result, the specific resistance of the dust core becomes large, so that the eddy current loss can be reduced.
  • the volume average particle size of the soft magnetic powder forming the soft magnetic particles is preferably 10 to 30 ⁇ m. If the volume average particle size is smaller than 10 ⁇ m, cracks (lamination or the like) are likely to occur in the molded body, and if the volume average particle size exceeds 30 ⁇ m, the eddy current loss increases and the frequency characteristics deteriorate.
  • the density (meaning the relative density) of the dust core described above is preferably 5.4 g / cm 3 or more and 6.5 g / cm 3 or less.
  • the powder magnetic core described above can be used for a chip inductor or an induction heating device.
  • the dust core according to the present embodiment can be used as a core for winding a winding in an inductor (particularly a chip inductor) or as a core in a high frequency coil of an induction heating device.
  • the powder magnetic core has a preparation step of preparing a powder for a powder magnetic core, a molding process of compressing the prepared material for a powder magnetic core to obtain a green compact, and a magnetic bleaching step of magnetically annealing the powder. It is manufactured by going through the steps in sequence.
  • the material for the dust core includes a soft magnetic powder and an insulating film covering the surface of the soft magnetic powder.
  • a material for a dust core is prepared by coating the soft magnetic powder with an insulating film.
  • the soft magnetic powder a soft magnetic alloy powder containing Fe as a main component (generally 80 mass% or more), an alloy element, and the balance as an unavoidable impurity is used.
  • the soft magnetic powder contains either or both of Si and Cr as essential alloying elements.
  • Si silicon
  • Cr Cr
  • the soft magnetic powder includes any one or more of other alloying elements (for example, Al, Ni, Co, Cu, B, Nb, Zr, etc.) as required. ) May be contained.
  • Fe-based amorphous alloys and Fe-based nanocrystalline alloys can also be used as the soft magnetic powder.
  • Fe—Si, Fe—Cr, Fe—Si—Cr, Fe—Si—Al, Fe—Al—Cr, Fe—Si—Cr—Al and the like can be used. Can be mentioned.
  • the total content of alloying elements in the soft magnetic powder shall be 2.0 mass% or more and 7.0 mass% or less.
  • the content of the essential alloy element is less than 2.0 mass%, the relative permeability, the Q value, and the volume resistivity decrease as described later because it is close to pure iron. Further, when the content of the essential alloy element exceeds 7.0 mass%, the powder becomes hard and is less likely to be plastically deformed during compression molding, and it is difficult to increase the density of the green compact. Therefore, the relative permeability of the dust core decreases.
  • soft magnetic powder those produced by the gas atomizing method are preferable because they have high purity.
  • soft magnetic powder produced by the water atomization method or other processes can also be used.
  • the volume average particle size of the soft magnetic powder is preferably 10 ⁇ m or more and 30 ⁇ m or less. If the volume average particle size is smaller than 10 ⁇ m, cracks (lamination or the like) are likely to occur in the molded body, and if the volume average particle size exceeds 30 ⁇ m, the eddy current loss increases and the frequency characteristics deteriorate.
  • the soft magnetic powder is a sphere with a uniform diameter, even if the powder is densely packed, gaps are created between the particles, and it is not possible to achieve a high density of the dust core. It is preferable to prepare the soft magnetic powder so as to have a particle size distribution in the range of, for example, about 1 ⁇ m to 100 ⁇ m so that the gap can be filled with the fine powder. At this time, the particle size distribution may have a single peak, or the particle size distribution may include a plurality of peaks. Further, two or more different kinds of soft magnetic powders can be mixed and used.
  • the soft magnetic powder contains a large amount of fine powder, the fluidity of the powder will decrease, causing problems such as segregation and intrusion of the powder into the clearance of the mold.
  • granulated powder in which fine powders are bound to each other with a binder can also be used as the soft magnetic powder.
  • Various organic binders and inorganic binders can be used as the binder for granulation.
  • the granulation method general methods such as rolling granulation, fluidized bed granulation, stirring granulation, compression granulation, extrusion granulation, crushing granulation, melt granulation, and spray granulation can be used.
  • the granulation method may be wet or dry.
  • the volume average particle size can be measured by using a laser diffraction / scattering type particle size distribution measuring device.
  • the insulating film that coats the soft magnetic powder is formed of a material that changes to SiO 2 regardless of the components of the atmospheric gas, which is transformed during heating due to magnetic annealing.
  • the insulating film since the material for the dust core is heated by magnetic annealing after the insulating film is formed, the insulating film is required to have heat resistance to the heating temperature (700 ° C. in this embodiment) at the time of magnetic annealing. Further, it is preferable to form an insulating film with a material having a small heat shrinkage during magnetic annealing. This is because if the heat shrinkage is too large, the insulation between the soft magnetic particles may be destroyed during magnetic annealing, and the soft magnetic particles may be energized.
  • a material containing Si and O for example, various silane coupling agents, various silicone oligomers, various silicone resins (for example, methyl silicone resin) and the like can be used. These materials may be used alone or in combination of two or more. Further, these materials can also be used in combination with a material containing Si but not O (for example, various silanes).
  • an insulating film covering the surface of the soft magnetic powder By adhering the material of the insulating film to the entire surface of the soft magnetic powder, an insulating film covering the surface of the soft magnetic powder can be formed.
  • the method for forming the insulating film is not particularly limited, and for example, mixing using a mixer, kneading using a pressurized kneader, coating using a fluidized bed, various chemical conversion treatments, and the like can be used.
  • the coating method may be either dry or wet.
  • the soft magnetic powder obtained in the preparation process is compression-molded with a mold having a predetermined shape to form a green compact.
  • a solid lubricant may be added to the powder magnetic core material.
  • solid lubricants include zinc stearate, calcium stearate, magnesium stearate, barium stearate, lithium stearate, iron stearate, aluminum stearate, stearic acid amide, ethylene bisstearate amide, oleic acid amide, and ethylene bisolein.
  • the solid lubricant may be used alone or in combination of several types.
  • the fixed lubricant may be blended with the soft magnetic powder as the raw material powder before the compression molding, or may be adhered to the wall surface of the mold.
  • the blending amount (or adhesion amount) at this time is preferably, for example, about 0.3 to 2.0 mass% with respect to the material for total dust core. Excessive blending of solid lubricants leads to a decrease in the density of the green compact, which leads to a decrease in magnetic properties and strength.
  • the green compact is subjected to magnetic annealing treatment for the purpose of removing the magnetostriction of the green compact obtained in the molding step.
  • the type of atmosphere gas for this annealing treatment is not particularly limited, but it is desirable to use an inert or reducing atmosphere gas so that the soft magnetic powder does not oxidize and the magnetic properties do not deteriorate.
  • these atmospheric gases include inert gases such as nitrogen and argon, and reducing gases such as hydrogen.
  • the type of atmospheric gas that can be used is not limited to the oxidizing one, which is different from Patent Document 1 described above.
  • the heating temperature (magnetic annealing temperature) during the magnetic annealing treatment should be set in consideration of the material of the target soft magnetic powder, for example, Fe-Si type, Fe-Cr type, Fe-Si-Cr type. When used, it is better to set it to 700 ° C. or higher and 850 ° C. or lower. This is because at temperatures below 700 ° C., magnetostriction cannot be sufficiently removed and iron loss cannot be sufficiently suppressed. Further, if the temperature exceeds 850 ° C., the eddy current loss increases due to the deterioration of the insulating film. When the methyl silicone resin is used as the material for the insulating coating, it is preferable to set the magnetic annealing temperature to 800 ° C. or higher and 850 ° C. or lower from the viewpoint of increasing the strength of the dust core.
  • the dust core after magnetic annealing is composed of the soft magnetic particles 10 derived from the soft magnetic powder, the insulating layer 11 derived from the insulating coating and covering the soft magnetic particles 10, and the insulating layer 11. It is formed in a porous form having a large number of pores 12 formed between them.
  • the insulating layer 11 is formed by the transformation of the insulating film by heating during magnetic annealing, and the main component is SiO 2 . Na, K, Mg, Al, and Ca may be contained as other elements constituting the insulating film.
  • the thickness of the insulating coating varies depending on the observation field of view, but if the thickness is adjusted to 0.05 to 0.6 ⁇ m on average, a dust core having desired characteristics can be obtained.
  • the type and content of the alloying element contained in the soft magnetic particles 10 are substantially the same as the type and content of the alloying element contained in the soft magnetic powder before magnetic annealing. Therefore, the total content of the alloying elements in the soft magnetic particles 10 is 2.0 mass% or more and 7.0 mass% or less. Since the total content of the alloying elements contained in the soft magnetic particles 10 (soft magnetic powder) is reduced in this way, it is possible to avoid a decrease in compressibility due to the hardening of the powder, and thereby a decrease in relative magnetic permeability. Can be avoided.
  • the insulating layer containing SiO 2 as a main component is obtained by heating a substance containing Si and O (silane coupling agent, silicone oligomer, silicone resin, etc.) with magnetic annealing, it relies on atmospheric gas. It is possible to form an insulating layer without the need for silicon. Therefore, oxygen does not need to enter when forming the insulating layer, and it is possible to form the insulating layer even inside a thick dust core.
  • Si and O silane coupling agent, silicone oligomer, silicone resin, etc.
  • the thickness of the insulating layer 11 is set to 0.05 ⁇ m to 0.6 ⁇ m.
  • the thickness of the insulating layer 11 is measured from a cross-sectional SEM photograph (about 10,000 times) taken by cutting the dust core. Specifically, the thickness of the insulating layer 11 existing between the Fe soft magnetic particles 10 can be measured in different 30 fields of view on the SEM photograph, and the average value thereof can be used as the thickness.
  • the thickness of the insulating layer 11 can be changed by adjusting the amount of the binder mixed with the soft magnetic powder in the preparation step.
  • the volume resistivity of the dust core manufactured by the above procedure is preferably 1 ⁇ 10 6 ⁇ cm or more. If the volume resistivity is less than 1 ⁇ 10 6 ⁇ cm, the specific resistance becomes small and the eddy current loss becomes large.
  • the "volume resistivity” here means the electrical resistance between both sides when a 1 m 3 cube is considered inside the magnetic core and a voltage is applied between the two sides thereof (JIS C2560-1).
  • An insulating film was formed on the surface of the soft magnetic powder using a silane coupling agent, and the soft magnetic powder with the insulating film was granulated using a silicone resin.
  • a ring-shaped test piece without an air gap (solid lubricant) is mixed with the powder after granulation, compression-molded at a predetermined pressure at room temperature, and magnetically annealed at a nitrogen temperature of 750 ° C. Powder magnetic core) was manufactured.
  • a high-density product (Examples 1 to 4 and Comparative Examples 1 to 4) having a density (relative density) of 5.8 to 6.5 g / cm 3 after heat treatment and a density after heat treatment (relative density)
  • Two types of low-density products (Example 5 and Comparative Example 5) having a relative density of 5.1 to 5.4 g / cm 3 were produced.
  • Fe-4.5Si-2.0Cr was used in Examples 1, 2 and 4 and Fe-2Si was used in Example 3 as the soft magnetic powder, and Example 5 was used. Fe-2.0Cr is used in. Further, as the soft magnetic powder, Fe-3.5Si-4.5Cr is used in Comparative Example 1, Fe-2Si is used in Comparative Example 2, and Fe-4.5Si-2.0Cr is used in Comparative Example 4. In Comparative Example 5, Fe-6.0Cr is used.
  • the evaluation items were relative permeability, Q value, and volume resistivity, assuming use in chip inductors.
  • a winding was wound around each test piece so as to have an inductance of 10 ⁇ H.
  • Q value two windings were wound around each test piece.
  • the relative magnetic permeability was measured using an LCR meter (5 kHz, 10 mA, constant current mode) in accordance with the method for measuring the initial magnetic permeability specified in JIS C2560-2: 2006.
  • the volume resistivity was measured according to the measuring method specified in JIS C2139-3-1: 2018.
  • the relative magnetic permeability was 60 or more
  • the Q value was 45 or more
  • the volume resistivity was 1 ⁇ 10 6 ⁇ cm or more.
  • FIG. 2 shows the measurement results of the above evaluation items when Fe-4.5Si-2.0Cr was used as the soft magnetic powder (Example 1).
  • Example 1 each evaluation item was measured for the test piece in which the type of soft magnetic powder and the average particle size were changed. The results are shown in FIG. 3 together with Example 1.
  • FIG. 2 and FIG. 3 the density and the relative magnetic permeability of Example 1 are slightly different, but this is due to the variation in quality due to the use of different test pieces.
  • Example 2 in FIG. 3 Fe-4.5Si-2.0Cr was used as the soft magnetic powder as in Example 1, while the volume average particle size of the soft magnetic powder was larger than that in Example 1.
  • Fe-2.0Si is used as the soft magnetic powder, while the volume average particle size of the soft magnetic powder is smaller than that of Example 1.
  • Comparative Example 1 uses Fe-3.5Si-4.5Cr as the soft magnetic powder, and Comparative Example 2 uses Fe-2.0Si as the soft magnetic powder (the volume average particle size is the same as that of Example 1). (Same as above), Comparative Example 3 uses pure iron powder instead of soft magnetic powder.
  • Example 1 in which the total content of the alloying elements in the soft magnetic powder was 7.0 mass%, and Comparative Example 1 in which the total content of the alloying elements was 8.0 mass (3.5 mass% + 4.5 mass%). From the comparison, it was clarified that the specific magnetic permeability was lower than the target value in Comparative Example 1 in which the amount of alloying elements contained in the soft magnetic powder was large. Further, from the comparison between Example 3 and Comparative Example 3, if the content of the alloying element of the soft magnetic powder is 2.0 mass% or more, the relative permeability, the Q value, and the volume resistivity all exceed the target values. It can be understood that
  • the particle size of the soft magnetic powder also affects the magnetic properties. Specifically, from the comparison between Example 1 and Example 2, it can be understood that even if the volume average particle size of the soft magnetic powder is coarsened to 30 ⁇ m, all the evaluation items exceed the target values. Further, from the comparison between Example 3 and Comparative Example 2, if the volume average particle size is reduced to 10 ⁇ m, the Q value and the volume resistivity can be improved even if the content of the alloying element is the lower limit. Therefore, if the volume average particle size of the soft magnetic powder is within the range of 10 ⁇ m or more and 30 ⁇ m or less, it is possible to secure the target value for all the evaluation items.
  • the thickness of the insulating layer is preferably 0.05 ⁇ m or more and 0.6 ⁇ m or less.
  • the quenching depth is adjusted by adjusting the frequency of the applied current and the powder core.
  • the magnetic permeability of the dust core is also adjusted, so a powder magnetic core with a low specific magnetic permeability (specific magnetic permeability less than 60), which is not used in chip inductors, may be required. Therefore, as long as it has the minimum relative permeability (specific permeability of 15 or more), even a low-density dust core may be used for an induction heating device.
  • the evaluation items were Q value, volume resistivity, and annular strength.
  • the pressure ring strength was measured according to JIS Z2507: 2000. Other measurement methods are the same as described above.
  • a Q value of 45 or more, a volume resistivity of 1 ⁇ 10 6 ⁇ cm or more, and a ring strength of 40 MPa or more were accepted.
  • Example 5 From the comparison between Example 5 and Comparative Example 5 in FIG. 5, if the density is 5.4 g / cm 3 or more, the magnetic characteristics (Q value, volume resistivity, required as the dust core for the induction heating device, It became clear that the pressure ring strength) was satisfied. Further, it was also found that the relative magnetic permeability is smaller than that of the high-density products (Examples 1 to 4), but the specific magnetic permeability that is not particularly problematic for the induction heating device can be obtained. Therefore, the density of the dust core after magnetic annealing is preferably 5.4 g / cm 3 or more.
  • the density of the powder magnetic core after magnetic quenching Is preferably 6.5 g / cm 3 or less.
  • the density is 6.0 g / cm 3 or more from the measurement results of Comparative Example 1 in FIG. 3, Example 4 in FIG. 4, and Comparative Example 4. Is preferable.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Dispersion Chemistry (AREA)
  • Metallurgy (AREA)
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  • Soft Magnetic Materials (AREA)

Abstract

Ce noyau aggloméré comprend une particule magnétique à faible champ coercitif et une couche isolante qui est formée sur la surface de la particule magnétique à faible champ coercitif. La particule magnétique à faible champ coercitif (10) contient un élément d'alliage qui contient un parmi Si et Cr, ou les deux. La teneur totale de l'élément en alliage dans la particule magnétique douce est de 2,0 % en masse à 7,0 % en masse. La couche isolante est principalement composée de SiO2. De plus, la couche isolante 11 a une épaisseur de 0,05 µm à 0,6 µm.
PCT/JP2021/032619 2020-09-29 2021-09-06 Noyau aggloméré WO2022070786A1 (fr)

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JP2020-163707 2020-09-29
JP2020163707A JP2022055966A (ja) 2020-09-29 2020-09-29 圧粉磁心

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WO2022070786A1 true WO2022070786A1 (fr) 2022-04-07

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003297624A (ja) * 2002-04-02 2003-10-17 Toyota Central Res & Dev Lab Inc 圧粉磁心およびその製造方法
JP2020027812A (ja) * 2018-08-09 2020-02-20 太陽誘電株式会社 金属磁性粒子を含む磁性基体及び当該磁性基体を含む電子部品

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003297624A (ja) * 2002-04-02 2003-10-17 Toyota Central Res & Dev Lab Inc 圧粉磁心およびその製造方法
JP2020027812A (ja) * 2018-08-09 2020-02-20 太陽誘電株式会社 金属磁性粒子を含む磁性基体及び当該磁性基体を含む電子部品

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