JP2016096237A - Magnetic member and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a magnetic member which has a desired non-planar shape even with no external force applied thereto while keeping a magnetic property; and a method for manufacturing such a magnetic member.SOLUTION: A magnetic member has elasticity, and is arranged by binding soft magnetic metal powder flat in shape with a binder component including a silicon oxide as a primary component. The magnetic member comprises 55 vol.% or more of the soft magnetic metal powder and 10-25 vol.% of pores. The magnetic member is arranged to have a non-planar part with no external force applied thereto.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a magnetic member, and more particularly to a member suitable for a housing or a magnetic yoke of a device that requires countermeasures against electromagnetic noise.

  A technique is known in which a magnetic sheet formed by molding a mixture containing a flat metal powder having soft magnetism and a binder is bent and used as a magnetic member.

  Patent Document 1 discloses an elastic magnetic core obtained by binding a soft magnetic metal powder having a flat shape with a binder component, which is 55% by volume or more of soft magnetic metal powder, 10% by volume or more, and 25% by volume. A technique relating to a flat-plate-shaped magnetic core having a binder component containing silicon oxide as a main component is described.

  Patent Document 2 discloses a high-resistance magnetic shield material in which a magnetic shield layer in which soft magnetic powder is dispersed and at least one insulating layer is provided in a resin, and includes a thermoplastic resin or a thermosetting resin. A technique relating to a magnetic shield material that can be bent into a certain shape when used is described.

  Patent Document 3 discloses a cylindrical composite magnetic body composed of flat soft magnetic powder and chlorinated polyethylene as a binder, and has a hard axis in the central axis direction of the cylinder. A technique related to an electromagnetic interference suppressor in which soft magnetic powder is oriented is described.

Japanese Patent No. 5474251 JP-A-6-252586 JP 2001-126904 A

  Patent Document 1 does not disclose a technical idea that a flat magnetic core is used while being bent. Therefore, there is a problem that it does not have sufficient flexibility to bend, and when external force is applied so as to form a curved surface, there is a possibility that minute cracks are generated and the magnetic properties are impaired.

  The magnetic shield material described in Patent Document 2 requires a certain amount of a resin composition in order to maintain a curved surface shape by binding a thermoplastic resin or a thermosetting resin. Therefore, there is a limit to increasing the volume ratio of the soft magnetic powder, and there is a problem that magnetic characteristics exceeding a certain value cannot be obtained.

  The composite magnetic material described in Patent Document 3 is also composed of a soft magnetic powder and a resin composition, and has the same problems as the magnetic shield material described in Patent Document 2. That is, there is a limit to increasing the volume ratio of the soft magnetic powder, and there is a problem that sufficient magnetic properties cannot be secured depending on the application.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above problems and to provide a magnetic member having a desired curved surface shape and a method for manufacturing the same while maintaining magnetic characteristics and applying no external force.

  The present invention is made by paying attention to a binding structure of a soft magnetic powder having a flat shape and a binder component mainly composed of silicon oxide and a manufacturing process thereof described in Patent Document 1.

  The composite magnetic body obtained by binding the soft magnetic powder with the resin composition is formed by dispersing the soft magnetic powder in the resin composition as exemplified in the invention described in Patent Document 2 or Patent Document 3.

  In order to form a composite magnetic body having such a structure so as to maintain a three-dimensional shape having a curved surface or a bent surface even when no external force is applied, a thermoplastic resin is used as described in paragraph 0020 of Patent Document 2. Although it may be heat-molded, in addition to the problem of form stability at high temperatures, thermoplastic resin cannot improve the filling rate of soft magnetic powder in the first place, and magnetic properties such as permeability are sufficient. Can't get to.

  In addition, in order to form a curved surface by extrusion molding as in the invention described in Patent Document 3, it is necessary to use a sufficient amount of the resin composition to form a flat plate. Therefore, like the invention described in Patent Document 2, the filling rate of the soft magnetic powder cannot be improved, and magnetic properties such as magnetic permeability cannot be sufficiently obtained.

  On the other hand, the magnetic sheet having a binder component mainly composed of silicon oxide described in Patent Document 1 cannot be thermoformed as in the invention described in Patent Document 2 due to the nature of the binder, and the invention described in Patent Document 3 In such extrusion molding, sufficient magnetic properties cannot be obtained. In addition, since the magnetic sheet described in Patent Document 1 is cracked when it is forced to bend due to its structure, it is difficult to process a curved surface by the methods of Patent Documents 2 and 3.

  In the magnetic sheet described in Patent Document 1, the inventors mixed soft magnetic powder together with a solvent and a thickener, heated under a certain condition, and volatilized the solvent without adding a new resin material. It has been found that the sheet can be bent.

  That is, a structure having a curved surface is obtained even when soft magnetic powder is bound by a binder component mainly composed of an inorganic substance by performing a heat treatment for thermally decomposing the organic component while maintaining the curved surface structure, and no external force is applied. It was found that it can be obtained.

  Therefore, according to the present invention, a magnetic member having a three-dimensional shape including a non-planar surface can be obtained without increasing the volume ratio of the binder component.

  In the bending process, the outer periphery of the curved surface of the magnetic sheet may be elongated, and fine cracks may occur near the surface of the outer periphery. However, while applying compressive force from the outer periphery, the organic component in the subsequent process is heated. By performing a heat treatment for decomposition, fine cracks are repaired.

  The magnetic member of the present invention is an elastic magnetic member obtained by binding a soft magnetic metal powder having a flat shape with a binder component containing silicon oxide as a main component, and the soft magnetic content is 55% by volume or more. It contains metal powder and 10% by volume or more and 25% by volume or less of pores, and has a non-planar part such as a curved surface or a bent surface without applying external force.

  The magnetic member of the present invention has a rubber hardness according to ISO7619-type D of 92 or more and 96 or less.

  The magnetic member of the present invention has a Young's modulus of 10 GPa or more and 90 GPa or less.

  The magnetic member of the present invention has an electrical resistivity of 100 Ω · m or more.

  The magnetic member of the present invention is characterized by being coated with a resin or a film.

  The magnetic component of the present invention is characterized by combining one or more of the magnetic members.

  The magnetic component of the present invention is characterized in that the magnetic member is formed in a casing shape.

  The method for producing a magnetic member of the present invention includes a step of applying a mixture containing a soft magnetic powder having a flat shape and a binder component mainly composed of silicon oxide and drying to obtain a plate-like body as a preform, A process of obtaining a molded body by compressing and molding the shaped body with a surface having at least a non-planar part, and holding the molded body in a state having a non-planar part in an atmosphere containing at least oxygen or nitrogen. It includes a heat treatment step for binding the soft magnetic powder with silicon oxide.

  The method for producing a magnetic member of the present invention includes a step of obtaining a plate-like body as a preform by applying a soft magnetic powder having a flat shape and a mixture containing a silicon oxide as a main component and containing a binder component, followed by drying. A step of obtaining a molded body by compressing and molding the body in a plane, and holding the molded body in a state having a non-planar part in an atmosphere containing at least oxygen or nitrogen to form a soft magnetic powder in silicon oxide It includes a heat treatment step of binding with the above.

  The method for producing a magnetic member of the present invention is characterized in that the magnetic member having a rubber hardness of 92 or more and 96 or less according to ISO7619-type D is obtained.

  The method for producing a magnetic member of the present invention is characterized in that a magnetic member having a Young's modulus of 10 GPa or more and 90 GPa or less is obtained.

  The magnetic member manufacturing method of the present invention is characterized in that a magnetic member having an electrical resistivity of 100 Ω · m or more is obtained.

  The method for producing a magnetic member of the present invention is characterized in that a magnetic member formed by coating with a resin or a film is obtained.

  According to the present invention, a magnetic member having a desired non-planar shape and a method for manufacturing the same can be obtained without reducing the volume ratio of the soft magnetic powder, that is, while maintaining the magnetic characteristics and without applying an external force. .

  Further, according to the present invention, a magnetic part such as an electromagnetic noise countermeasure part suitable for use in the vicinity of a motor of a hybrid vehicle, for example, having a three-dimensional shape with a casing or lid of a portable device can be obtained.

It is a perspective view which shows embodiment in the magnetic member of this invention. FIG. 2A is an explanatory view showing a first embodiment of the magnetic member of the present invention, FIG. 2A is a sectional view of a preform, FIG. 2B is a sectional view of the molded body, and FIG. Sectional drawing of a member, FIG.2 (d) is structure explanatory drawing of a magnetic member. FIG. 3A is an explanatory view showing a second embodiment of the magnetic member of the present invention, FIG. 3A is a sectional view of a preform, FIG. 3B is a sectional view of the molded body, and FIG. Sectional drawing of a member is shown.

  Hereinafter, embodiments of the present invention will be described in detail.

(First embodiment)
FIG. 1 is a perspective view showing an embodiment of the magnetic member of the present invention.
2A and 2B are explanatory views showing a first embodiment of the magnetic member of the present invention. FIG. 2A is a sectional view of a preform, FIG. 2B is a sectional view of the molded body, and FIG. FIG. 2C is a cross-sectional view of the magnetic member, and FIG. 2D is an explanatory diagram of the structure of the magnetic member.

  The magnetic member 100 has curved surface portions 5 at both ends so that it can be used as, for example, a lid of a portable device.

  Below, the manufacturing method is explained in full detail.

  A flat soft magnetic powder 1 and a binder component 2 are mixed to prepare a slurry, which is applied onto, for example, a PET (polyethylene terephthalate) film and dried to obtain a plate-shaped preform. This state is shown in FIG. In addition, the binder component 2 at this stage includes a thermosetting binder component, a solvent, and a thickener in the applied state, and the solvent is removed by drying.

  Next, the preform is cut into a predetermined size, a plurality of sheets are laminated as necessary, and sandwiched with a jig (not shown) and compression molded to obtain a molded body. This state is shown in FIG.

  The jig is made of, for example, a split mold and has a curved surface portion 5 so as to have the shape shown in FIG. That is, a preform is obtained by holding the preform with a curved surface.

  For compression molding, for example, a sheet in a curved mold is preferably subjected to pressure molding at a molding pressure of 200 MPa for 1 hour at a temperature of 150 ° C.

  Next, the compact is fixed to a jig having the curved surface portion 5, that is, heat-treated in an atmosphere containing at least oxygen or nitrogen while being held on the curved surface, to obtain the magnetic member 200. This state is shown in FIG.

  Any jig can be used as long as it is made of a material that is excellent in strength and heat resistance and can expose the molded body to a heat treatment atmosphere. For example, a combination of mesh plates made of stainless steel is preferable. Moreover, you may remove and use a part of split mold used for the compression molding of the previous process.

  For example, the heat treatment is preferably performed in a nitrogen atmosphere at 600 ° C. for 1 hour.

  Note that the organic component contained in the binder component 2 is almost thermally decomposed by heat treatment in an oxygen or nitrogen-containing atmosphere, and the glass component is mainly composed of silicon oxide contained in the thermosetting binder component as a main component. The binder component, that is, the inorganic component remains. This state is shown in FIG.

  That is, when a part 4 of the magnetic member is enlarged and schematically illustrated, the soft magnetic powder 1 is bound by the inorganic component 21 and has a structure including the pores 3.

  With the above structure, the magnetic member 200 has a high strength with a rubber hardness of 92 or more and 96 or less according to ISO7619-type D.

  With the above structure, the magnetic member 200 has elasticity with a Young's modulus of 10 GPa or more and 90 GPa or less.

  With the above structure, the magnetic member 200 has a high electrical resistivity of 100 Ω · m or more, and at the same time has good insulating properties.

  With the above structure, the magnetic member 200 can increase the filling rate of the soft magnetic powder, and can improve the saturation magnetic flux density, the relative magnetic permeability, and the thermal conductivity.

  Specifically, in order to obtain a sufficient thermal conductivity while maintaining magnetic characteristics, the volume ratio of the soft magnetic powder is preferably included in the range of 55% to 85% by volume.

  When the filling rate of the soft magnetic powder is within this range, a high saturation magnetic flux density, a high relative magnetic permeability, and a high thermal conductivity can be achieved at the same time.

  The flat soft magnetic powder can be appropriately selected from known materials and used, but iron-based metal magnetic powder, particularly Fe—Si—Al-based alloy is particularly preferable. Soft magnetic metal powders such as permalloy and Zr—Co—Ta alloys are also preferred.

  If the soft magnetic powder is in a flat shape, the effect of the present invention is obtained. However, the flat metal powder is impregnated with a resin and cured to produce a cured body, the cured body is polished, and polished using a scanning electron microscope. The aspect ratio when observing the shape of the flat metal powder located on the surface is preferably 10 or more in order to increase the magnetic permeability in the in-plane direction of the curved surface, and the particle diameter is preferably 50 μm or more in major axis.

  The binder component can be appropriately selected from known materials as long as it has thermosetting properties and mainly contains silicon oxide as an inorganic material, and methyl silicone resin is particularly preferable.

  The solvent can be appropriately selected from known materials and used, but ethanol is particularly preferable.

  The thickener can be appropriately selected from known materials, and polyacrylic acid ester is particularly preferable.

  In addition, in order to improve strength or designability, a plurality of magnetic members 200 may be stacked and pressed or bonded to form a magnetic component.

  Similarly, a resin or film may be coated on the surface of the magnetic member or the magnetic component in order to improve the strength or the design.

  The resin or film to be coated is preferably selected from general coating materials according to the application and design, and is preferably an acrylic resin or a polyolefin resin.

(Second Embodiment)
FIG. 3 is an explanatory view showing a second embodiment of the magnetic member of the present invention. FIG. 3 (a) is a cross-sectional view of a preform, FIG. 3 (b) is a cross-sectional view of the formed body, and FIG. c) is a cross-sectional view of a magnetic member.

  Another method for manufacturing the magnetic member 100 illustrated in FIG. 1 will be described in detail below.

  A flat soft magnetic powder 1 and a binder component 2 are mixed to prepare a slurry, which is applied onto a PET film and dried, for example, to obtain a plate-shaped preform. This state is shown in FIG. In addition, the binder component 2 at this stage includes a thermosetting binder component, a solvent, and a thickener in the applied state, and the solvent is removed by drying.

  Next, the preform is cut into a predetermined size, held with a jig (not shown), and compression molded to obtain a molded body. This state is shown in FIG.

  The jig is composed of a mold having a set of parallel planes, for example. That is, the preform is held on a flat surface to obtain a molded body.

  Note that the compression molding conditions in the present embodiment are the same as those in the first embodiment.

  Next, the molded body is fixed to a jig (not shown) having another curved surface. That is, the magnetic member 300 is obtained by heat-treating in an atmosphere containing at least oxygen or nitrogen while holding the curved surface having the curved surface portion 5 shown in FIG. This state is shown in FIG.

  Any jig can be used as long as it is made of a material that is excellent in strength and heat resistance and can expose the molded body to a heat treatment atmosphere. For example, a combination of mesh plates made of stainless steel is preferable.

  Note that the heat treatment conditions are the same as those in the first embodiment.

  As described in the first embodiment, the organic component contained in the binder component 2 is almost thermally decomposed by the heat treatment in an atmosphere containing at least oxygen or nitrogen, and is contained in the thermosetting binder component as the main component. The binder component consisting of vitreous whose main component is silicon oxide, that is, the inorganic component remains.

  When a part of the magnetic member is enlarged and modeled, the soft magnetic powder is bound by an inorganic component and has a structure including pores.

  With the above structure, the magnetic member 300 has a high strength with a rubber hardness of 92 or more and 96 or less according to ISO7619-type D.

  With the above structure, the magnetic member 300 has elasticity with a Young's modulus of 10 GPa or more and 90 GPa or less.

  With the above structure, the magnetic member 300 has a high electrical resistivity of 100 Ω · m or more and also has good insulation properties.

  With the above structure, the magnetic member 300 can increase the filling rate of the soft magnetic powder, and can improve the saturation magnetic flux density, the relative magnetic permeability, and the thermal conductivity.

  Specifically, in order to obtain a sufficient thermal conductivity while maintaining magnetic characteristics, the volume ratio of the soft magnetic powder is preferably included in the range of 55% to 85% by volume.

  When the filling rate of the soft magnetic powder is within this range, a high saturation magnetic flux density, a high relative magnetic permeability, and a high thermal conductivity can be achieved at the same time.

  The flat soft magnetic powder, binder component, solvent, and thickener are preferably those described in the first embodiment.

  In order to improve strength or designability, a plurality of magnetic members 300 may be stacked and pressed or bonded to form a magnetic component.

  Similarly, a resin or film may be coated on the surface of the magnetic member or the magnetic component in order to improve the strength or the design.

  The resin or film to be coated is preferably appropriately selected from general coating materials according to the application and design.

  In this Embodiment, it replaced with the metal mold | die of the shape which has the curved surface used in Embodiment 1, and the molded object was obtained using the metal mold | die which has a parallel plane for the following reasons.

  If a mold having a curved surface is used for compression molding to obtain a molded body, the pressurization state may lack uniformity, and it is necessary to strictly adjust the pressurization conditions.

  Therefore, when obtaining a molded body having a more complicated shape, it is preferable that the compression molding is reliably performed while maintaining a flat state and having pores.

  That is, when obtaining a molded body with a curved surface portion with a small curvature, the manufacturing method of Embodiment 1 with a small number of work steps is preferable, and when obtaining a molded body with a curved surface portion with a large curvature, the manufacturing method of this embodiment is performed. preferable.

  As a soft magnetic metal raw material powder, a gas atomized powder of Fe—Si—Al alloy having an average particle diameter D50 of 55 μm was used.

  In order to flatten the powder shape, the raw material powder was pulverized for 12 hours using a ball mill, and further subjected to heat treatment at 700 ° C. for 3 hours in a nitrogen atmosphere to obtain a powder having a flat shape. The produced flat metal powder has an average major axis (Da) of 60 μm, an average maximum thickness (ta) of 3 μm, and an average aspect ratio (Da / ta) of 20.

  The aspect ratio of the flat metal powder is obtained by impregnating a compressed metal powder with a resin and curing it, polishing the cured body, and observing the shape of the flat metal powder on the polished surface with a scanning electron microscope. It was. Specifically, for 30 flat metal powders, the major axis (D) and the thickness (t) of the thickest part were measured, and the average value of the aspect ratio (D / t) was calculated.

  Subsequently, a flat metal powder, a solvent, a thickener, and a thermosetting binder component were mixed to prepare a slurry. Specifically, a mixture comprising a solvent, a thickener, and a thermosetting binder component was mixed for 5 hours at a rotational speed of 250 revolutions per minute. Next, the slurry was put into a container and mixed for 1 hour at a rotation speed of 100 revolutions per minute.

  Ethanol was used as the solvent. A polyacrylic acid ester was used as the thickener. A methyl silicone resin was used as the thermosetting binder component. At this time, the addition amount of the solid content of the methyl silicone resin is 5% by weight with respect to the metal powder.

  The slurry was applied on the PET film by the die slot method. Then, it dried at 60 degreeC for 1 hour, the solvent was removed, and the plate-shaped preform was produced.

  The preform was cut using a punching die to obtain a plurality of rectangular sheets having a width of 50 mm and a length of 80 mm. Further, 15 sheets of these sheets were stacked and placed in a mold having two curved surface portions.

  The sheet in the mold was subjected to pressure molding for 1 hour at a molding pressure of 2 MPa at a temperature of 150 ° C. to obtain a molded body.

  Subsequently, the molded body was heat-treated at 700 ° C. for 1 hour in the atmosphere with the inner peripheral portion side of the mold having the curved portion removed, that is, with the outer peripheral portion side of the curved portion remaining in the mold. In addition, a magnetic member having a thickness of 1 mm having two curved surface portions was obtained.

  By this heat treatment, the organic component was almost completely pyrolyzed and did not remain in the magnetic member. In addition, by this heat treatment, the solid content of the methyl silicone resin became a binder component composed of a vitreous containing silicon oxide as a main component, and the amount of heat was reduced. The loss on heating of the solid content of the methyl silicone resin was 22% by weight.

  When the magnetic member was used as a part of the casing of the in-vehicle device, it was useful as a countermeasure against electromagnetic noise and had good heat resistance and shape retention.

  As a raw material powder, a gas atomized powder of Fe—Si—Al alloy having an average particle diameter D50 of 55 μm was prepared. The raw material powder was treated with a ball mill for 8 hours, and further subjected to heat treatment at 700 ° C. for 3 hours in a nitrogen atmosphere to produce a flat metal powder having soft magnetism.

  The metal powder had an average major axis (Da) of 60 μm, an average maximum thickness (ta) of 3 μm, and an average aspect ratio (Da / ta) of 20.

  This metal powder was mixed with a thickener and a thermosetting binder component to prepare a slurry. The solvent was ethanol, and the thickener was polyacrylate. A methyl silicone resin was used as the thermosetting binder component.

  The slurry was applied on a PET film by the die slot method, and then dried for 1 hour at a temperature of 60 ° C. to remove the solvent, thereby obtaining a plate-shaped preform.

  This preform was cut using a punching die to obtain a plurality of rectangular sheets having a width of 30 mm and a length of 40 mm. Ten sheets of these sheets were stacked and sealed in a planar mold so as to form a plate.

  The sheet sealed in the mold was subjected to pressure molding at 150 ° C. and a molding pressure of 2 MPa for 1 hour. In order to remove molding distortion, the preform was heat-treated in a nitrogen atmosphere at 350 ° C. for 1 hour to obtain a molded article having a thickness of 2.2 mm.

  Subsequently, the molded body was placed while being molded on a jig having a curved surface portion made of a stainless mesh plate, and was heat-treated in a nitrogen atmosphere at 600 ° C. for 1 hour to obtain a magnetic member.

The magnetic member had a value of 100 Ω · m or more as a volume resistivity. The density was 4.9 g / cm ³ , and the volume filling factor of the metal component determined from this density was about 67%.

  A film coating was applied to the surface of the magnetic member.

  When the magnetic member was used as a battery lid of a portable device, in addition to measures against electromagnetic noise, the case strength and design were increased, and the heat resistance and shape retention were good.

  From the above, a magnetic member having a desired non-planar shape and a method for producing the same were obtained without reducing the volume ratio of the soft magnetic powder, that is, while maintaining the magnetic characteristics and without applying an external force.

  While the embodiments and examples of the present invention have been described above, the present invention is not limited to the above, and changes and modifications can be made without departing from the gist of the present invention. That is, various changes and modifications that can be made by those skilled in the art are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 Soft magnetic powder 2 Binder component 21 Inorganic substance component 3 Hole 4 Part of magnetic member 5 Curved surface part 100, 200, 300 Magnetic member

Claims (13)

  A soft magnetic metal powder having a flat shape is bound by a binder component mainly composed of silicon oxide, and is a magnetic member having elasticity, which is 55% by volume or more of the soft magnetic metal powder and 10% by volume. As described above, a magnetic member comprising 25% by volume or less of voids and having a non-planar portion without applying an external force.   The magnetic member according to claim 1, wherein the rubber hardness according to ISO7619-type D is 92 or more and 96 or less.   The magnetic member according to claim 1 or 2, wherein Young's modulus is 10 GPa or more and 90 GPa or less.   The magnetic member according to any one of claims 1 to 3, wherein the magnetic member has an electrical resistivity of 100 Ω · m or more.   5. The magnetic member according to claim 1, wherein at least a part thereof is covered with a resin or a film.   A magnetic component comprising a combination of one or more magnetic members according to claim 1.   A magnetic component comprising the magnetic member according to claim 1 formed in a casing shape.   Applying a mixture containing a soft magnetic powder having a flat shape and a binder component mainly composed of silicon oxide and drying to obtain a plate-like body, and holding the plate-like body on a surface having at least a non-planar portion And a heat treatment step of holding the plate-like body in a state having a non-planar portion in an atmosphere containing at least oxygen or nitrogen and binding the soft magnetic powder with silicon oxide. A method for producing a magnetic member.   A step of applying a soft magnetic powder having a flat shape, a mixture containing silicon oxide as a main component and containing a binder component and drying to obtain a plate-like body, a step of holding the plate-like body in a flat surface, and a compression molding step; A method for producing a magnetic member, comprising: a heat treatment step of holding a state body having a non-planar portion in an atmosphere containing at least oxygen or nitrogen and binding a soft magnetic powder with silicon oxide.   The method for producing a magnetic member according to claim 8 or 9, wherein the rubber hardness according to ISO7619-type D is 92 or more and 96 or less.   The method for producing a magnetic member according to claim 8, wherein Young's modulus is 10 GPa or more and 90 GPa or less.   The method of manufacturing a magnetic member according to claim 8, wherein the magnetic member has an electrical resistivity of 100 Ω · m or more.   13. The method for producing a magnetic member according to claim 8, wherein the magnetic member is coated with a resin or a film.

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