Magnetic Particles, Method for Producing the Same, Magnetic Core, and Coil Component

Abstract

Provided are magnetic particles used in the manufacture of a compacted powder magnetic core having a sufficiently high relative magnetic permeability and specific resistance. A magnetic particle 1 has a core 2 of a metallic magnetic material and a film 3 covering the surface of the core 2. The film 3 contains a reaction product obtained by using a first metal alkoxide that does not contain a metal atom-carbon atom bond in one molecule; and a second metal alkoxide that contains two or more metal atom-carbon atom bonds in one molecule.

Description

Technical Field

[0001] The present invention also relates to magnetic particles, a method for manufacturing the same, and a magnetic core and a coil component using the magnetic particles Background Art

[0002] In various electrical devices and electronic devices, coil components such as inductors and choke coils are used. The coil component generally consists of a coil and a magnetic core. In recent years, with the continuous development of the miniaturization of electrical devices and electronic devices, the coil components used for them are also required to be miniaturized. In addition, in addition to being small, the coil component is also required to have excellent magnetic, electrical, and mechanical properties. Therefore, the magnetic core is required to have high magnetic permeability, high magnetic flux density, low loss, and high strength. Among them, in the use in the high-frequency region, in order to suppress the increase in eddy current loss, the magnetic core is required to have a high specific resistance. In order to meet such requirements, a magnetic core obtained by forming fine particles (powder) of a soft magnetic material, covering the surface of each particle with an insulating film, and compression molding is known. For example, Patent Document 1 discloses a magnetic core obtained by compression molding a powder of magnetic particles whose surfaces are coated with carbon and further coated with a metal oxide mainly composed of silicon oxide.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Laid-Open No. 2013-209693 Summary of the Invention

[0006] However, the inventors of the present application have found the following problems in the conventional magnetic cores (for example, the magnetic cores described in Patent Document 1):

[0007] The magnetic particles are liable to adhere to or aggregate with each other, and have insufficient filling properties during compression molding. Therefore, the relative magnetic permeability of the obtained magnetic core is low;

[0008] The film does not have sufficient damage resistance and is liable to be damaged during compression molding. Therefore, the specific resistance of the obtained magnetic core is low.

[0009] Therefore, an object of the present invention is to provide magnetic particles used in the manufacture of a magnetic core having a relatively high magnetic permeability and a relatively high specific resistance, a method for manufacturing the same, and a magnetic core and a coil component using the magnetic particles.

[0010] The inventors of the present application have conducted in-depth research to solve the above problems, and as a result, have found that by forming a specific film on the surface of the core of the magnetic material used in the manufacture of the magnetic core, a magnetic core having a high specific resistance and a high relative magnetic permeability can be manufactured, and the present invention has been completed.

[0011] The present invention relates to a magnetic particle,

[0012] A core having a metallic magnetic body and a film covering the surface of the core,

[0013] wherein the film contains a first metal alkoxide that does not contain a metal atom-carbon atom bond in one molecule; and

[0014] a second metal alkoxide that contains two or more metal atom-carbon atom bonds in one molecule

[0015] and a reaction product obtained therefrom.

[0016] The present invention further relates to a method for manufacturing magnetic particles, comprising:

[0017] mixing a core of a metallic magnetic body, a first metal alkoxide that does not contain a metal atom-carbon atom bond in one molecule, a second metal alkoxide that contains two or more metal atom-carbon atom bonds in one molecule, and a solvent;

[0018] hydrolyzing and drying the first metal alkoxide and the second metal alkoxide to obtain magnetic particles having the core of the metallic magnetic body and a film covering the surface of the core.

[0019] According to the magnetic particles of the present invention, a magnetic core having a sufficiently high relative magnetic permeability and specific resistance can be manufactured.

[0020] BRIEF DESCRIPTION OF THE DRAWINGS BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic cross-sectional view showing the core of the magnetic particles of the present invention and the film covering the core.

[0022] Figure 2 is a schematic conceptual view showing the main bonding state of the interface between the film and the core in the magnetic particles of the present invention.

[0023] Figure 3 is a schematic conceptual view showing the main structure of the film in the magnetic particles of the present invention.

[0024] Figure 4 is a schematic front view showing a coil component using the magnetic core of the present invention.

[0025] Figure 5 is a schematic internal perspective three-dimensional view showing another coil component using the magnetic particles of the present invention.

[0026] Figure 6 is a schematic conceptual view showing the main structure of the film in conventional magnetic particles.

[0027] SYMBOL DESCRIPTION

[0028] 1 Magnetic particles

[0029] 2 Core

[0030] 3 Coating

[0031] 4 Divalent hydrocarbon group

[0032] 10 Coil component

[0033] 11 Compressed powder magnetic core

[0034] 12 Coil

[0035] 20 Coil component

[0036] 21 Unit body

[0037] 22 Coil Detailed implementation mode

[0038] [Magnetic particles]

[0039] As Figure 1 shown, the magnetic particles of the present invention are magnetic particles 1 having a core 2 of a metallic magnetic body and a coating 3 covering the surface of the core 2. Figure 1 is a schematic cross-sectional view showing the core of the magnetic particle of the present invention and the coating covering the core.

[0040] The core refers to particles of a metallic magnetic body, and its surface is covered with a coating. The metallic magnetic body is not particularly limited, but a soft magnetic material is preferred, especially a soft magnetic material containing iron. By using a soft magnetic material, a magnetic core with high magnetic flux density and high magnetic permeability can be obtained.

[0041] As the soft magnetic material containing iron, it is not particularly limited. For example, iron, Fe-Si alloy, Fe-Al alloy, Fe-Ni alloy, Fe-Co alloy, Fe-Si-Al alloy, Fe-Si-Cr alloy, etc. can be cited.

[0042] The average particle diameter of the core of the metallic magnetic body is not particularly limited. For example, it can be 0.01 μm to 300 μm. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably 0.5 μm to 200 μm, and more preferably 1 μm to 100 μm.

[0043] The average particle diameter uses D50. D50 is the particle diameter at the point where the cumulative value becomes 50% in the cumulative curve obtained by calculating the particle size distribution based on volume and setting the total volume to 100%.

[0044] In this specification, the average particle diameter uses the value measured by HELOS (H3190) & RODOS (manufactured by Sympatec).

[0045] Compared with the core 2, the coating 3 is a layer that can be called a "shell", usually an electrically insulating coating. The coating contains a reaction product of a first metal alkoxide that does not contain a metal atom-carbon atom bond in one molecule and a second metal alkoxide that contains two or more metal atom-carbon atom bonds in one molecule, and can be composed of, for example, the reaction product of the first metal alkoxide and the second metal alkoxide. The reaction product is usually a sol-gel reaction product.

[0046] Specifically, the coating is not formed by stacking multiple layers formed by each of the above metal alkoxides, but has a mesh structure (single-layer structure) formed by the reactants of the above metal alkoxide mixture. The first metal alkoxide has a higher reactivity. As Figure 2 shown, at the interface between the coating 3 and the core 2, the coating 3 is fixed to the core 2 mainly through relatively strong bonds. On the other hand, the second metal alkoxide prevents the formation of a dense mesh structure, forms the coating 3 through a moderately rough mesh structure with stress relaxation properties (or softness), and imparts slipperiness to the coating surface. More specifically, as Figure 3 shown, for example, when the second metal alkoxide is a compound represented by the following general formula (2A), the "stress relaxation properties (or softness)", "moderately rough mesh structure", and "slipperiness" of the coating 3 are provided by the divalent hydrocarbon group 4 of the second metal alkoxide. For example, if the coating has "stress relaxation properties (or softness)" and "moderately rough mesh structure", the coating has sufficient damage resistance and is not easily damaged even during compression molding, so the obtained magnetic core can have a sufficiently high specific resistance. In addition, for example, if the coating has "slipperiness", the magnetic particles are not easily attached or aggregated to each other and have sufficient filling properties during compression molding, so the obtained magnetic core can have a sufficiently high relative magnetic permeability. Moreover, the second metal alkoxide is included in the coating by chemical bonding (specifically, covalent bonding) with the first metal alkoxide, so different from additives included only by mixing, it is not easily exuded from the coating to the outside even over time or with environmental changes. Therefore, the sufficiently high relative magnetic permeability and specific resistance obtained in the present invention can be continuously obtained even over time or with environmental changes. When the coating does not contain components from the second metal alkoxide, for example, as Figure 6 shown, the coating becomes a relatively dense mesh structure and does not have "stress relaxation properties (or softness)" and "slipperiness", so the relative magnetic permeability and specific resistance decrease. Figure 2 is a schematic conceptual diagram showing the main bonding state of the interface between the coating and the core in the magnetic particles of the present invention. Figure 3 is a schematic conceptual diagram showing the main structure of the coating in the magnetic particles of the present invention. Figure 6 is a schematic conceptual diagram showing the main structure of the coating in conventional magnetic particles. As Figure 3As shown, the coating film 3 contains metal atoms not bonded to carbon atoms and metal atoms bonded to carbon atoms.

[0047] It should be noted that the coating film 3 may be in direct contact with the surface of the core 2, or an insulating coating film may be additionally disposed between the coating film 3 and the core 2.

[0048] The first metal alkoxide is a metal alkoxide that does not contain a metal atom-carbon atom bond in one molecule, and all the bonds possessed by the metal are bonded to alkoxy groups (-OR 1 ). The metal atom-carbon atom bond refers to a direct covalent bond between a metal atom and a carbon atom. The carbon atom in the metal atom-carbon atom bond refers to a carbon atom constituting a monovalent hydrocarbon group (such as an alkyl group and an alkenyl group) or a carbon atom constituting a divalent hydrocarbon group (such as an alkylene group). The first metal alkoxide does not have such a metal atom-carbon atom bond in one molecule.

[0049] Specifically, the first metal alkoxide is a compound represented by the following general formula (1) or a mixture thereof.

[0050] M 1 (OR 1 ) x (1)

[0051] In formula (1), M 1 is a metal atom, which is Li, Na, Mg, K, Ca, Cu, Sr, Y, Ba, Ce, Ta, Bi, Si, Ti, Al or Zr, preferably Si, Ti, Al or Zr. From the viewpoint of further higher relative magnetic permeability and specific resistance, Si, Ti or Al is preferred, Si or Al is more preferred, and Si is further preferred.

[0052] x is the valence of M 1 , which is an integer from 1 to 4, preferably 3 or 4. When M 1 is Si, Ti or Zr, x is 4. When M 1 is Al, x is 3.

[0053] R 1 are each independently an alkyl group having 1 to 10 carbon atoms or a group represented by the general formula: -C(R 2 )=CH-CO-R 3 (wherein, R 2 and R 3 are as described later). From the viewpoint of further higher relative magnetic permeability and specific resistance, an alkyl group having 1 to 10 carbon atoms is preferred, and an alkyl group having 1 to 5 carbon atoms is more preferred. As R 1The alkyl group, for example, may include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, etc. For the single or multiple Rs corresponding to the number of x 1 , all Rs 1 may be independently selected from the above alkyl groups respectively, or all Rs 1 may be the same group selected from the above alkyl groups.

[0054] R 2 is an alkyl group having 1 to 10 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably an alkyl group having 1 to 5 carbon atoms. As the alkyl group of R 2 , the same alkyl groups as those of the alkyl group of R 1 can be cited.

[0055] R 3 is an alkyl group having 1 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms or an alkenyloxy group having 1 to 30 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably an alkyl group having 1 to 20 (more preferably 1 to 10, further preferably 1 to 5) carbon atoms, an alkoxy group having 10 to 30 (especially 14 to 24) carbon atoms or an alkenyloxy group having 10 to 30 (especially 14 to 24) carbon atoms. As the preferred alkyl group of R 3 , the same alkyl groups as those of the alkyl group of R 1 and undecyl, lauryl, tridecyl, myristyl, pentadecyl, cetyl, heptadecyl, stearyl, nonadecyl, eicosyl, etc. can be cited. As the alkoxy group of R 3 , for example, a group represented by the formula: -O-C p H 2p+1 (wherein p is an integer from 1 to 30) can be cited. As the alkenyloxy group of R 3 , for example, a group represented by the formula: -O-C q H 2q－1 (wherein q is an integer from 1 to 30) can be cited.

[0056] In formula (1), when two adjacent Rs 1 among the multiple Rs 1 are alkyl groups, they can be bonded to each other and together with the oxygen atom to which these two Rs 1 are bonded and the M 1 atom to which the oxygen atom is bonded form a ring (for example, a 5- to 8-membered ring, especially a 6-membered ring). As a ring formed by bonding two adjacent Rs 1 to each other, for example, a 6-membered ring represented by the general formula (1X) can be cited.

[0057]

[0058] In formula (1X), R 4 , R 5 and R 6 Each of R is independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms from the viewpoint of higher relative magnetic permeability and specific resistance. 4 , R 5 and R 6 The total number of carbon atoms is usually 0 to 12, and preferably 2 to 8 from the viewpoint of higher relative magnetic permeability and specific resistance. 4 , R 5 and R 6 The alkyl group may be exemplified by 1 The alkyl group is the same alkyl group.

[0059] As the first metal alkoxide, for example, compounds represented by the following general formulae (1A), (1B), (1B'), (1C) and (1D) can be cited. From the viewpoint of further high relative permeability and specific resistance, the first metal alkoxide is preferably a compound represented by the general formula (1A), (1B), (1C) or (1D) or a mixture thereof, more preferably a compound represented by the general formula (1A), (1B) or (1C) or a mixture thereof, further preferably a compound represented by the general formula (1A) or (1C) or a mixture thereof, and particularly preferably a compound represented by the general formula (1A) or a mixture thereof.

[0060] Si(OR 1 )4 (1A)

[0061] In formula (1A), R 1 are independently the same as R in formula (1) 1 The same R 1 From the perspective of higher relative permeability and resistivity, R 1 Each independently is preferably an alkyl group having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms.

[0062] Specific examples of the compound (1A) represented by such a general formula are shown in the following table.

[0063] Table 1

[0064] Specific examples of compound (1A)

[0065] Compound <![CDATA[R 1 > <![CDATA[R 1 > <![CDATA[R 1 > <![CDATA[R 1 > 1A-1 Ethyl Ethyl Ethyl Ethyl 1A-2 Methyl Methyl Methyl Methyl 1A-3 Butyl Butyl Butyl Butyl 1A-4 Isopropyl Isopropyl Isopropyl Isopropyl 1A-5 Ethyl Ethyl Ethyl Isopropyl

[0066] Ti(OR 1 )4 (1B)

[0067] In formula (1B), R1 are each independently the R in formula (1) 1 the same R 1 . From the viewpoints of further higher relative magnetic permeability and specific resistance, R 1 is each independently preferably an alkyl group having 1 to 10 carbon atoms or a group represented by the above general formula: -C(R 2 )=CH-CO-R 3 (wherein, R 2 and R 3 are the same as R 2 and R 3 described in the general formula (1)), and more preferably an alkyl group having 1 to 10 (especially 1 to 5) carbon atoms.

[0068] In formula (1B), from the viewpoints of further higher relative magnetic permeability and specific resistance, R 2 and R 3 are each preferably the following groups. R 2 is an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms. As the alkyl group of R 2 , an alkyl group the same as the alkyl group of R 1 can be cited. R 3 is an alkyl group having 1 to 30 carbon atoms, preferably an alkyl group having 1 to 20 (more preferably 1 to 10, still more preferably 1 to 5) carbon atoms. As the preferred alkyl group of R 3 , an alkyl group the same as the alkyl group of R 1 and undecyl, dodecyl, tridecyl, myristyl, pentadecyl, cetyl, heptadecyl, stearyl, nonadecyl, eicosyl, etc. can be cited.

[0069] Specific examples of the compound (1B) represented by such a general formula are shown in the following table.

[0070] Table 2

[0071] Specific examples of the compound (1B)

[0072] Compound <![CDATA[R 1 > <![CDATA[R 1 > <![CDATA[R 1 > <![CDATA[R 1 > 1B-1 Butyl Butyl Butyl Butyl 1B-2 Isopropyl Isopropyl Isopropyl Isopropyl 1B-3 Ethyl Ethyl Ethyl Ethyl 1B-4 Methyl Methyl Methyl Methyl 1B-5 Isopropyl Isopropyl <![CDATA[-C(CH3)=CH-CO-CH3]]> <![CDATA[-C(CH3)=CH-CO-CH3]]> 1B-6 Isopropyl Isopropyl <![CDATA[-C(CH3)=CH-CO-C2H5]]> <![CDATA[-C(CH3)=CH-CO-C2H5]]> 1B-7 Butyl Butyl <![CDATA[-C(CH3)=CH-CO-CH3]]> <![CDATA[-C(CH3)=CH-CO-CH3]]> 1B-8 Butyl Butyl <![CDATA[-C(CH3)=CH-CO-C2H5]]> <![CDATA[-C(CH3)=CH-CO-C2H5]]> 1B-9 Ethyl Ethyl <![CDATA[-C(CH3)=CH-CO-CH3]]> <![CDATA[-C(CH3)=CH-CO-CH3]]> 1B-10 Ethyl Ethyl <![CDATA[-C(CH3)=CH-CO-C2H5]]> <![CDATA[-C(CH3)=CH-CO-C2H5]]> 1B-11 Methyl Methyl <![CDATA[-C(CH3)=CH-CO-CH3]]> <![CDATA[-C(CH3)=CH-CO-CH3]]> 1B-12 Methyl Methyl <![CDATA[-C(CH3)=CH-CO-C2H5]]> <![CDATA[-C(CH3)=CH-CO-C2H5]]>

[0073]

[0074] In formula (1B’), Ra 1 , Ra 2 , Ra 3 , Ra 4 , Ra 5 and Ra 6 are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and preferably an alkyl group having 1 to 5 carbon atoms from the viewpoints of further higher relative magnetic permeability and specific resistance. As Ra1 , Ra 2 , Ra 3 , Ra 4 , Ra 5 and Ra 6 The alkyl groups of and Ra are the same as the alkyl group of R 1 .

[0075] Specific examples of the compound (1B’) represented by such a general formula are shown in the following table.

[0076] Table 3

[0077] Specific examples of the compound (1B’)

[0078] Compound <![CDATA[Ra 1 > <![CDATA[Ra 2 > <![CDATA[Ra 3 > <![CDATA[Ra 4 > <![CDATA[Ra - > <![CDATA[Ra 6 > 1B’-1 n-Propyl Ethyl Hydrogen Atom n-Propyl Ethyl Hydrogen Atom

[0079] A1(OR 1 )3 (1C)

[0080] In formula (1C), R 1 are each independently the same as R in formula (1) 1 . From the viewpoint of further higher relative magnetic permeability and specific resistance, R 1 are each independently preferably an alkyl group having 1 to 10 carbon atoms or a group represented by the above general formula: -C(R 1 )=CH-CO-R 2 (wherein, R 3 and R 2 are each the same as R 3 and R 2 and R 3 described in general formula (1)), more preferably an alkyl group having 1 to 10 (especially 1 to 5) carbon atoms.

[0081] In formula (1C), from the viewpoint of further higher relative magnetic permeability and specific resistance, R 2 and R 3 are each preferably the following groups. R 2 is an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms. As the alkyl group of R 2 , an alkyl group the same as the alkyl group of R 1 can be mentioned. R 3 is an alkoxy group having 1 to 30 carbon atoms or an alkenyloxy group having 1 to 30 carbon atoms, preferably an alkoxy group having 10 to 30 (especially 14 to 24) carbon atoms or an alkenyloxy group having 10 to 30 (especially 14 to 24) carbon atoms. As the alkoxy group of R 3 , for example, a group represented by the formula: -O-C p H 2p+1 (wherein, p is an integer of 1 to 30) can be mentioned. As the alkyl group of R 3An alkenyloxy group, for example, may include a group represented by the formula: -O-C q H 2q-1 (wherein q is an integer of 1 to 30).

[0082] Specific examples of the compound (1C) represented by such a general formula are shown in the following table.

[0083] Table 4

[0084] Specific examples of the compound (1C)

[0085] Compound <![CDATA[R 1 > <![CDATA[R 1 > <![CDATA[R 1 > 1C-1 Isopropyl Isopropyl Isopropyl 1C-2 sec-Propyl sec-Propyl sec-Propyl 1C-3 Ethyl Ethyl Ethyl 1C-4 Methyl Methyl Methyl 1C-5 Isopropyl Isopropyl <![CDATA[-C(CH3)=CH-CO-C 18 H 35 > 1C-6 Isopropyl Isopropyl <![CDATA[-C(CH3)=CH-CO-C 18 H 37 > 1C-7 sec-Propyl sec-Propyl <![CDATA[-C(CH3)=CH-CO-C 18 H 35 > 1C-8 sec-Propyl sec-Propyl <![CDATA[-C(CH3)=CH-CO-C 18 H 37 > 1C-9 Ethyl Ethyl <![CDATA[-C(CH3)=CH-CO-C 18 H 36 <!-- 6 -->]]> 1C-10 Ethyl Ethyl <![CDATA[-C(CH3)=CH-CO-C 18 H 37 > 1C-11 Methyl Methyl <![CDATA[-C(CH3)=CH-CO-C 18 H 35 > 1C-12 Methyl Methyl <![CDATA[-C(CH3)=CH-CO-C 18 H 37 >

[0086] Zr(OR 1 )4 (1D)

[0087] In formula (1D), R 1 are each independently the same as R in formula (1) 1 . From the viewpoint of further higher relative magnetic permeability and specific resistance, R 1 are each independently preferably an alkyl group having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms. 1 Specific examples of the compound (1D) represented by such a general formula are shown in the following table.

[0088] Table 5

[0089] Table 5

[0090] Specific examples of the compound (1D)

[0091] Compound <![CDATA[R 1 > <![CDATA[R 1 > <![CDATA[R 1 > <![CDATA[R 1 > 1D-1 Isopropyl Isopropyl Isopropyl Isopropyl 1D-2 Butyl Butyl Butyl Butyl 1D-3 Ethyl Ethyl Ethyl Ethyl 1D-4 Methyl Methyl Methyl Methyl 1D-5 Methyl Methyl Methyl Isopropyl

[0092] The compound (1) represented by the general formula (1) can also be obtained as a commercial product or can be manufactured by a known method.

[0093] For example, the compound (1A) can be obtained as tetraethyl orthosilicate (manufactured by Tokyo Chemical Industry Co., Ltd.) which is a commercial product.

[0094] In addition, for example, the compound (1B) can be obtained as tetrabutyl orthotitanate (manufactured by Tokyo Chemical Industry Co., Ltd.), titanium tetraisopropoxide (manufactured by Tokyo Chemical Industry Co., Ltd.), T-50 (manufactured by Nippon Soda Co., Ltd.) which are commercial products.

[0095] In addition, for example, the compound (1B’) can be obtained as TOG (manufactured by Nippon Soda Co., Ltd.) which is a commercial product.

[0096] In addition, for example, the compound (1C) can be obtained as aluminum triisopropoxide (manufactured by Kanto Chemical Co., Inc.) which is a commercial product.

[0097] Further, for example, the compound (1D) can be obtained as commercially available zirconium(IV) tetrabutoxide (trade name TBZR, manufactured by Nippon Soda Co., Ltd.), zirconium(IV) tetraisopropoxide (manufactured by Tokyo Chemical Industry Co., Ltd.), or ZR-181 (manufactured by Nippon Soda Co., Ltd.).

[0098] With respect to the total weight of the metal alkoxides to be incorporated (e.g., the total weight of the first metal alkoxide and the second metal alkoxide), the amount of the first metal alkoxide required to obtain the film 3 (i.e., the reactants constituting the film) is usually 5% by weight to 95% by weight, preferably 20% by weight to 80% by weight, more preferably 30% by weight to 80% by weight, still more preferably 40% by weight to 80% by weight, and particularly preferably 50% by weight to 75% by weight, from the viewpoint of further higher relative magnetic permeability and specific resistance. It should be noted that the above weight ratio (% by weight) is the ratio when the total weight of the first metal alkoxide and the second metal alkoxide is set to 100% by weight. The film can be produced using two or more types of the first metal alkoxide, and in this case, as long as their total amount is within the above range. The amount of the first metal alkoxide required to obtain the film 3 can also be the ratio of the amount of the first metal alkoxide incorporated with respect to the total amount of the first metal alkoxide and the second metal alkoxide incorporated.

[0099] The second metal alkoxide is a metal alkoxide containing two or more (e.g., 2 to 20, particularly 2 to 12) metal atom-carbon atom bonds in one molecule. In the second metal alkoxide, the carbon atoms constituting two or more metal atom-carbon atom bonds are the carbon atoms constituting a monovalent hydrocarbon group (e.g., an alkyl group and an alkenyl group) and / or the carbon atoms constituting a divalent hydrocarbon group (e.g., an alkylene group). In the second metal alkoxide, from the viewpoint of further higher relative magnetic permeability and specific resistance, the carbon atoms constituting all of the two or more metal atom-carbon atom bonds are preferably the carbon atoms constituting a divalent hydrocarbon group (e.g., an alkylene group). The metal atom of the second metal alkoxide is Li, Na, Mg, K, Ca, Cu, Sr, Y, Ba, Ce, Ta, Bi, Si, Ti, Al, or Zr, preferably Si, Ti, Al, or Zr, more preferably Si, Ti, or Al, still more preferably Si or Al, and particularly preferably Si. The second metal alkoxide contains two or more such metal atom-carbon atom bonds in one molecule.

[0100] When the carbon atoms constituting the metal atom-carbon atom bonds in the second metal alkoxide are the carbon atoms constituting a divalent hydrocarbon group, the second metal alkoxide is a compound having two or more groups represented by the following general formula (2) (e.g., a trialkoxysilyl group) in one molecule.

[0101] -M 2 (OR 21 ) y (2)

[0102] In formula (2), M 2 is a metal atom, which is Li, Na, Mg, K, Ca, Cu, Sr, Y, Ba, Ce, Ta, Bi, Si, Ti, Al or Zr, preferably Si, Ti, Al or Zr, more preferably Si, Ti or Al, still more preferably Si or Al, and particularly preferably Si.

[0103] y is the valence of M 2 . When M 2 is Si, Ti or Zr, y is 3. When M 2 is Al, y is 2.

[0104] R 21 are each independently an alkyl group having 1 to 10 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. Examples of such alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl and the like. For multiple R 21 , all R 21 can be independently selected from the above alkyl groups, or all R 21 can also be the same group selected from the above alkyl groups.

[0105] Two or more groups of the general formula (2) (such as trialkoxysilyl) possessed by the second metal alkoxide can be independently selected from the groups of the general formula (2) (such as trialkoxysilyl), or can also be the same group.

[0106] Specific examples of the group represented by such a general formula (2) (such as trialkoxysilyl) are shown in the following table.

[0107] Table 6

[0108] Specific examples of the group of the general formula (2)

[0109] Group <![CDATA[M 2 > y <![CDATA[R 21 > <![CDATA[R 21 > <![CDATA[R 21 > 2A-1 Si 3 Methyl Methyl Methyl 2A-2 Si 3 Ethyl Ethyl Ethyl 2A-3 Si 3 Isopropyl Isopropyl Isopropyl 2A-4 Si 3 Butyl Butyl Butyl 2A-5 Si 3 Methyl Methyl Isopropyl

[0110] When the carbon atoms constituting two or more all metal atom-carbon atom bonds in the second metal alkoxide are carbon atoms constituting a divalent hydrocarbon group, the second metal alkoxide can be, for example, a compound represented by the following general formula (2A), (2B), (2C), (2E) or (2F), or a mixture thereof. Among them, from the viewpoint of further higher relative magnetic permeability and specific resistance, the second metal alkoxide is preferably a compound represented by the general formula (2A), (2B) or (2C), or a mixture thereof, more preferably a compound represented by the general formula (2A) or (2B), or a mixture thereof, and further preferably a compound represented by the general formula (2A).

[0111] When the carbon atoms constituting two or more all metal atom-carbon atom bonds in the second metal alkoxide are carbon atoms constituting a monovalent hydrocarbon group, the second metal alkoxide can be, for example, a compound represented by the following general formula (2D), or a mixture thereof.

[0112] (R 211 O)3Si-R 31 -Si(OR 212 )3 (2A)

[0113] In formula (2A), R 211 and R 212 are each independently the same group as R 21 in formula (2). Specifically, the three R 211 and the three R 212 are each independently an alkyl group having 1 to 10 carbon atoms, and from the viewpoint of further higher relative magnetic permeability and specific resistance, preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. The three R 211 and the three R 212 can each independently be selected from R 21 of the above general formula (2), or can also be the same group as each other.

[0114] R 31 is a divalent hydrocarbon group having 1 to 20 carbon atoms, and from the viewpoint of further higher relative magnetic permeability and specific resistance, preferably a divalent hydrocarbon group having 1 to 10 carbon atoms, more preferably a divalent hydrocarbon group having 2 to 8 carbon atoms, further preferably a divalent hydrocarbon group having 3 to 7 carbon atoms, particularly preferably a divalent hydrocarbon group having 4 to 7 carbon atoms, and most preferably a divalent hydrocarbon group having 5 to 7 carbon atoms. R 31 can be a branched hydrocarbon group, preferably a straight-chain hydrocarbon group. The divalent hydrocarbon group of R 31 can be a divalent saturated aliphatic hydrocarbon group (such as an alkylene group), or can also be a divalent unsaturated aliphatic hydrocarbon group (such as an alkenylene group). From the viewpoint of further higher relative magnetic permeability and specific resistance, as R 31The divalent hydrocarbon group is preferably a divalent saturated aliphatic hydrocarbon group (especially an alkylene group). As R 31 The divalent saturated aliphatic hydrocarbon group (especially an alkylene group), for example, may include a group represented by -(CH2) p -(wherein p is an integer of 1 to 10, more preferably 2 to 8, still more preferably 3 to 7, particularly preferably 4 to 7, and most preferably 5 to 7), etc.

[0115] Specific examples of the compound (2A) represented by such a general formula are shown in the following table.

[0116] Table 7

[0117] Specific examples of the compound (2A)

[0118] Compound <![CDATA[R 211 > <![CDATA[R 211 > <![CDATA[R 211 > <![CDATA[R 31 > <![CDATA[R 212 > <![CDATA[R 212 > <![CDATA[R 212 > 2A-1 Methyl Methyl Methyl <![CDATA[-CH2CH2-]]> Methyl Methyl Methyl 2A-2 Methyl Methyl Methyl <![CDATA[-CH2CH2CH2CH2CH2CH2-]]> Methyl Methyl Methyl 2A-3 Ethyl Ethyl Ethyl <![CDATA[--CH2CH2-]]> Ethyl Ethyl Ethyl 2A-4 Ethyl Ethyl Ethyl <![CDATA[-CH2CH2CH2CH2CH2CH2-]]> Ethyl Ethyl Ethyl 2A-5 Methyl Methyl Butyl <![CDATA[-CH2CH2-]]> Methyl Methyl Butyl

[0119]

[0120] In formula (2B), R 211 , R 212 , R 213 and R 214 are the same groups as R 21 in formula (2). Specifically, the three R 211 , the three R 212 , the three R 213 and the three R 214 are each independently an alkyl group having 1 to 10 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. The three R 211 , the three R 212 , the three R 213 and the three R 214 can each independently be selected from R 21 of the above general formula (2), or they may also be the same groups as each other.

[0121] R 32 are each independently a divalent hydrocarbon group having 1 to 20 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably a divalent hydrocarbon group having 1 to 10 carbon atoms, and more preferably a divalent hydrocarbon group having 6 to 10 carbon atoms. The divalent hydrocarbon group of R 32 can be a divalent saturated aliphatic hydrocarbon group (such as an alkylene group), or it may also be a divalent unsaturated aliphatic hydrocarbon group (such as an alkenylene group). From the viewpoint of further higher relative magnetic permeability and specific resistance, the divalent hydrocarbon group of R 32 is preferably a divalent saturated aliphatic hydrocarbon group (especially an alkylene group). As R 32A divalent saturated aliphatic hydrocarbon group (especially an alkylene group), for example, a group represented by -(CH2) q -(wherein q is an integer of 1 to 10, more preferably 6 to 10), and the like. All R 32 can be independently selected from this R 32 , or they can also be the same group as each other.

[0122] R 33 are each independently a monovalent hydrocarbon group having 1 to 10 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, a monovalent hydrocarbon group having 1 to 5 carbon atoms is preferred, and a monovalent hydrocarbon group having 1 to 3 carbon atoms is more preferred. As the R 33 monovalent hydrocarbon group can be a saturated aliphatic hydrocarbon group (such as an alkyl group), or it can also be an unsaturated aliphatic hydrocarbon group (such as an alkenyl group). From the viewpoint of further higher relative magnetic permeability and specific resistance, the R 33 monovalent hydrocarbon group is preferably a saturated aliphatic hydrocarbon group (especially an alkyl group). As the R 33 monovalent saturated aliphatic hydrocarbon group (especially an alkyl group), for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, etc. can be mentioned. All R 33 can be independently selected from this R 33 , or they can also be the same group as each other.

[0123] Specific examples of the compound (2B) represented by such a general formula are shown in the following table.

[0124] Table 8

[0125] Specific examples of the compound (2B)

[0126]

[0127] (R 211 O)3Si-R 34 -NH-R 35 -NH-R 36 -Si(OR 212 )3 (2C)

[0128] In formula (2C), R 211 and R 212 are the same groups as R 21 in formula (2). Specifically, the three R 211 and the three R 212 are each independently an alkyl group having 1 to 10 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, an alkyl group having 1 to 5 carbon atoms is preferred, and an alkyl group having 1 to 3 carbon atoms is more preferred. The three R211 and three Rs 212 may be independently selected from Rs of the above general formula (2), 21 or may also be the same group as each other.

[0129] R 34 , R 35 and R 36 are each independently a divalent hydrocarbon group having 1 to 10 carbon atoms, and from the viewpoint of further higher relative magnetic permeability and specific resistance, preferably a divalent hydrocarbon group having 1 to 5 carbon atoms. As R 34 , R 35 and R 36 , the divalent hydrocarbon group may be a divalent saturated aliphatic hydrocarbon group (such as an alkylene group), or may also be a divalent unsaturated aliphatic hydrocarbon group (such as an alkenylene group). From the viewpoint of further higher relative magnetic permeability and specific resistance, as R 34 , R 35 and R 36 , the divalent hydrocarbon group is preferably a divalent saturated aliphatic hydrocarbon group (especially an alkylene group). As the divalent saturated aliphatic hydrocarbon group (especially an alkylene group) of R 34 , R 35 and R 36 , for example, groups represented by -(CH2) r - (wherein r is an integer of 1 to 10, more preferably 1 to 5) can be cited. All of R 34 , R 35 and R 36 may be independently selected from the above divalent hydrocarbon groups, or may also be the same group as each other. From the viewpoint of further higher relative magnetic permeability and specific resistance, the total number of carbon atoms of R 34 , R 35 and R 36 is preferably 3 to 20, more preferably 6 to 10.

[0130] Specific examples of the compound (2C) represented by such a general formula are shown in the following table.

[0131] Table 9

[0132] Specific examples of compound (2C)

[0133] Compound <![CDATA[3 R's 111 , 3 R's 212 > <![CDATA[R 34 > <![CDATA[R 35 > <![CDATA[R 36 > 2C-1 Methyl <![CDATA[-CH2CH2CH2-]]> <![CDATA[-CH2CH2-]]> <![CDATA[-CH2CH2CH2-]]> 2C-2 Ethyl <![CDATA[-CH2CH2CH2-]]> <![CDATA[-CH2CH2-]]> <![CDATA[-CH2CH2CH2-]]>

[0134] (R 211 )2-Si(OR 212 )2 (2D)

[0135] In formula (2D), R 211 and R 212 are each independently the same as R in formula (2) 21The same group. Specifically, two Rs 211 and two Rs 212 are each independently an alkyl group having 1 to 10 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. Two Rs 211 and two Rs 212 can each independently be selected from R 21 of the above general formula (2), or they can also be the same group as each other.

[0136] Specific examples of the compound (2D) represented by such a general formula are shown in the following table.

[0137] Table 10

[0138] Specific examples of compound (2D)

[0139] Compound <![CDATA[2 R 211 > <![CDATA[2 R's 212 > 2D-1 Methyl Methyl 2D-2 Methyl Ethyl

[0140]

[0141] In formula (2E), R 212 and R 213 are the same groups as R 21 in formula (2). Specifically, three Rs 212 and three Rs 213 are each independently an alkyl group having 1 to 10 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. Three Rs 212 and three Rs 213 can each independently be selected from R 21 of the above general formula (2), or they can also be the same group as each other.

[0142] Rs 32 are each independently a divalent hydrocarbon group having 1 to 20 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably a divalent hydrocarbon group having 1 to 10 carbon atoms, more preferably a divalent hydrocarbon group having 4 to 8 carbon atoms. The divalent hydrocarbon group as R 32 can be a divalent saturated aliphatic hydrocarbon group (such as an alkylene group), or it can also be a divalent unsaturated aliphatic hydrocarbon group (such as an alkenylene group). From the viewpoint of further higher relative magnetic permeability and specific resistance, the divalent hydrocarbon group as R 32 is preferably a divalent saturated aliphatic hydrocarbon group (especially an alkylene group). As the divalent saturated aliphatic hydrocarbon group (especially an alkylene group) of R 32 , for example, it can be exemplified by -(CH2) q-(wherein q is an integer of 1 to 20, preferably 1 to 10, more preferably 4 to 8) and the like. All R 32 may each independently be selected from this R 32 , or they may also be the same group as each other.

[0143] R 33 are each independently a monovalent hydrocarbon group having 1 to 10 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably a monovalent hydrocarbon group having 1 to 5 carbon atoms, and more preferably a monovalent hydrocarbon group having 1 to 3 carbon atoms. As the R 33 monovalent hydrocarbon group, it may be a saturated aliphatic hydrocarbon group (e.g., alkyl group), or it may also be an unsaturated aliphatic hydrocarbon group (e.g., alkenyl group). From the viewpoint of further higher relative magnetic permeability and specific resistance, as the R 33 monovalent hydrocarbon group, it is preferably a saturated aliphatic hydrocarbon group (especially an alkyl group). As the R 33 monovalent saturated aliphatic hydrocarbon group (especially an alkyl group), for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, etc. can be mentioned. All R 33 may each independently be selected from this R 33 , or they may be the same group as each other.

[0144] R 34 are each independently a monovalent hydrocarbon group having 1 to 30 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, and more preferably a monovalent hydrocarbon group having 1 to 5 carbon atoms. As the R 34 monovalent hydrocarbon group, it may be a saturated aliphatic hydrocarbon group (e.g., alkyl group), or it may also be an unsaturated aliphatic hydrocarbon group (e.g., alkenyl group). From the viewpoint of further higher relative magnetic permeability and specific resistance, as the R 34 monovalent hydrocarbon group, it is preferably a saturated aliphatic hydrocarbon group (especially an alkyl group). As the R 34 monovalent saturated aliphatic hydrocarbon group (especially an alkyl group), for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, etc. can be mentioned. All R 34 may each independently be selected from this R 34 , or they may be the same group as each other.

[0145] Specific examples of the compound (2E) represented by such a general formula are shown in the following table.

[0146] Table 11

[0147] Specific examples of the compound (2E)

[0148]

[0149]

[0150] In formula (2F), R 212 , R 213 and R 214 are each independently the same group as R 21 in formula (2). Specifically, the three Rs 212 , the three Rs 213 and the three Rs 214 are each independently an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, from the viewpoint of further higher relative magnetic permeability and specific resistance. The three Rs 212 , the three Rs 213 and the three Rs 214 may each independently be selected from R 21 of the above general formula (2), or may also be the same group as each other.

[0151] R 32 is each independently a divalent hydrocarbon group having 1 to 20 carbon atoms, preferably a divalent hydrocarbon group having 1 to 10 carbon atoms, more preferably a divalent hydrocarbon group having 1 to 5 carbon atoms, from the viewpoint of further higher relative magnetic permeability and specific resistance. The divalent hydrocarbon group as R 32 may be a divalent saturated aliphatic hydrocarbon group (e.g., alkylene group), or may also be a divalent unsaturated aliphatic hydrocarbon group (e.g., alkenylene group). From the viewpoint of further higher relative magnetic permeability and specific resistance, the divalent hydrocarbon group as R 32 is preferably a divalent saturated aliphatic hydrocarbon group (especially alkylene group). As the divalent saturated aliphatic hydrocarbon group (especially alkylene group) of R 32 , for example, a group represented by -(CH2) q -(wherein q is an integer of 1 to 10, more preferably 1 to 5) can be cited. All Rs 32 may each independently be selected from this R 32 , or may also be the same group as each other.

[0152] Specific examples of the compound (2F) represented by such a general formula are shown in the following table.

[0153] Table 12

[0154] Specific examples of the compound (2F)

[0155] Compound <![CDATA[3 R's 212 > <![CDATA[3 R's 213 > <![CDATA[3 R's 214 > <![CDATA[3 R's 32 > 2F-1 Methyl Methyl Methyl <![CDATA[-CH2CH2CH2-]]> 2F-2 Ethyl Ethyl Ethyl <![CDATA[-CH2CH2CH2-]]>

[0156] The compound (2A) represented by the general formula (2A), the compound (2B) represented by the general formula (2B), the compound (2C) represented by the general formula (2C), the compound (2D) represented by the general formula (2D), the compound (2E) represented by the general formula (2E), and the compound (2F) represented by the general formula (2F) can be obtained as commercially available products or can also be produced by known methods.

[0157] For example, the compound (2A) can be obtained as commercially available 1,1-bis(trimethoxysilyl)methane (manufactured by Tokyo Chemical Industry Co., Ltd.), 1,2-bis(trimethoxysilyl)ethane (manufactured by Tokyo Chemical Industry Co., Ltd.), 1,6-bis(trimethoxysilyl)hexane (manufactured by Tokyo Chemical Industry Co., Ltd.), 1,8-bis(trimethoxysilyl)octane (manufactured by Shin-Etsu Chemical Co., Ltd.), 1,10-bis(trimethoxysilyl)decane (manufactured by Gelest, Inc.).

[0158] In addition, for example, the compound (2C) can be obtained as commercially available X-12-5263HP (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0159] In addition, for example, the compound (2D) can be obtained as commercially available dimethyldimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.).

[0160] In addition, for example, the compound (2F) can be obtained as commercially available tris[3-(trimethoxysilyl)propyl] isocyanurate (manufactured by Tokyo Chemical Industry Co., Ltd.).

[0161] The second metal alkoxide can be, for example, a compound represented by the general formula (2A), (2B), (2C), (2D), (2E), or (2F) or a mixture thereof. From the viewpoint of further higher relative magnetic permeability and specific resistance, the second metal alkoxide is preferably a compound represented by the general formula (2A) or a mixture thereof.

[0162] The amount of the second metal alkoxide required to obtain the film 3 (i.e., the reactants constituting the film) is usually 5% by weight to 95% by weight relative to the total weight of the combined metal alkoxides (e.g., the total weight of the first metal alkoxide and the second metal alkoxide). From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably 20% by weight to 80% by weight, more preferably 20% by weight to 70% by weight, still more preferably 20% by weight to 60% by weight, and particularly preferably 25% by weight to 50% by weight. It should be noted that the above weight ratio (% by weight) is the ratio when the total weight of the first metal alkoxide and the second metal alkoxide is set to 100% by weight. The film can be made using two or more second metal alkoxides. In this case, as long as their total amount is within the above range. The amount of the second metal alkoxide required to obtain the film 3 can also be the proportion of the amount of the second metal alkoxide relative to the total amount of the first metal alkoxide and the second metal alkoxide.

[0163] The film 3 can be made using a third metal alkoxide. Specifically, the film 3 can be made using a third metal alkoxide, or it can also be made without using a third metal alkoxide. In the case of making the film 3 using a third metal alkoxide, the film 3 contains the reaction product of the first metal alkoxide, the second metal alkoxide, and the third metal alkoxide, and can be composed of, for example, the reaction product of the first metal alkoxide, the second metal alkoxide, and the third metal alkoxide.

[0164] The third metal alkoxide is a metal alkoxide that contains only one metal atom-carbon atom bond in one molecule. For example, among the bonds of the metal, one bond is bonded to a monovalent hydrocarbon group (-R 12 ) and all the remaining bonds are bonded to an alkoxy group (-OR 11 ). In the third metal alkoxide, the metal atom-carbon atom bond is a direct covalent bond between the metal atom and the carbon atom. In the third metal alkoxide, the carbon atom constituting the metal atom-carbon atom bond is the carbon atom constituting a monovalent hydrocarbon group (e.g., an alkyl group and an alkenyl group). The third metal alkoxide contains only one such metal atom-carbon atom bond in one molecule. The metal atom of the third metal alkoxide is Li, Na, Mg, K, Ca, Cu, Sr, Y, Ba, Ce, Ta, Bi, Si, Ti, Al, or Zr, preferably Si, Ti, Al, or Zr, more preferably Si, Ti, or Al, still more preferably Si or Al, and particularly preferably Si. The third metal alkoxide reduces the surface free energy of the film 3 and imparts more sufficient slidability to the surface of the film 3. It is considered that such more sufficient slidability is based on the monovalent hydrocarbon group (R 12 ) possessed by the third metal alkoxide.

[0165] The third metal alkoxide can be, for example, a compound represented by the following general formula (3).

[0166] R 12 -Si(OR 11 )3 (3)

[0167] In formula (3), R 11 is independently and respectively an alkyl group having 1 to 10 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. As such alkyl groups, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, etc. can be cited. All R 11 can be independently selected from the above alkyl groups respectively, or all R 11 can also be the same group selected from the above alkyl groups.

[0168] R 12 is a monovalent hydrocarbon group having 8 to 30 carbon atoms. From the viewpoint of further higher relative magnetic permeability and specific resistance, it is preferably a monovalent hydrocarbon group having 12 to 24 carbon atoms, and more preferably a monovalent hydrocarbon group having 14 to 20 carbon atoms. As the monovalent hydrocarbon group of R 12 , it can be a saturated aliphatic hydrocarbon group (such as an alkyl group), or it can also be an unsaturated aliphatic hydrocarbon group (such as an alkenyl group). From the viewpoint of further higher relative magnetic permeability and specific resistance, as the monovalent hydrocarbon group of R 12 , it is preferably a saturated aliphatic hydrocarbon group (especially an alkyl group). As the monovalent saturated aliphatic hydrocarbon group (especially an alkyl group) of R 12 , for example, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, etc. can be cited.

[0169] Specific examples of the compound (3) represented by such a general formula are shown in the following table.

[0170] Table 13

[0171] Specific examples of compound (3)

[0172] Compound <![CDATA[R 12 > R <![CDATA[R 11 > <![CDATA[R 11 > 3A-1 Octadecyl Methyl Methyl Methyl 3A-2 Hexadecyl Methyl Methyl Methyl 3A-3 Decyl Methyl Methyl Methyl 3A-4 Octadecyl Ethyl Ethyl Ethyl 3A-5 Hexadecyl Ethyl Ethyl Ethyl 3A-6 Decyl Ethyl Ethyl Ethyl

[0173] The compound (3) represented by the general formula (3) can also be obtained as a commercially available product, or can be manufactured by a known method.

[0174] For example, the compound (3) can be obtained as commercially available octadecyltrimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), hexadecyltrimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), decyltrimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.).

[0175] The compounding amount of the third metal alkoxide required to obtain the film 3 (i.e., the reactants constituting the film) is usually 0 wt% to 50 wt% relative to the total weight of the first metal alkoxide and the second metal alkoxide, and preferably 2 wt% to 50 wt% from the viewpoint of further higher relative magnetic permeability and specific resistance. The film can be made using two or more kinds of the third metal alkoxide. In this case, as long as their total amount is within the above range. The compounding amount of the third metal alkoxide required to obtain the film 3 can also be the ratio of the compounding amount of the third metal alkoxide relative to the total compounding amount of the first metal alkoxide and the second metal alkoxide.

[0176] The film 3 usually has an average film thickness of, for example, 1 nm to 200 nm, particularly 1 nm to 100 nm.

[0177] The average film thickness of the film can be measured by a scanning transmission electron microscope (STEM, HD-2300A (manufactured by Hitachi High-Technologies Corporation)) to observe the cross section of the magnetic particles. This average film thickness can be measured at two places for each of a total of 10 particles and the average value can be used.

[0178] [Method for manufacturing magnetic particles]

[0179] The magnetic particles of the present invention can be manufactured by a method including stirring a magnetic core and a specified metal alkoxide in a solvent. As the magnetic core, a magnetic core having an insulating film formed on its surface in advance can be used. The specified metal alkoxide refers to a metal alkoxide mixture containing at least a first metal alkoxide and a second metal alkoxide. The solvent is preferably an alkaline solvent. After stirring, specifically, by filtering, washing, and heat-drying the magnetic core, magnetic particles having a film with a mesh structure formed on the surface of the magnetic core can be obtained. It should be noted that if the surface of the magnetic core can be coated with the specified metal alkoxide mixture, the coating method is not limited to the above method, and other known coating methods such as spraying and dry mixing can also be used. Therefore, the magnetic particles of the present invention can be manufactured by a method including mixing the core of a mixed metal magnetic body, a first metal alkoxide, a second metal alkoxide, and a solvent; hydrolyzing and drying the first metal alkoxide and the second metal alkoxide.

[0180] The compounding ratio (i.e., the usage ratio) of the first metal alkoxide and the second metal alkoxide (and the third metal alkoxide contained as required) in the solvent usually directly becomes the content ratio of the component from the first metal alkoxide and the component from the second metal alkoxide (and the component from the third metal alkoxide contained as required) in the film, and thus can be set to a compounding ratio corresponding to the desired content ratio.

[0181] As long as the magnetic particles of the present invention can be obtained, the ratio of the total compounding amount of the first metal alkoxide and the second metal alkoxide (and the third metal alkoxide included as needed) to the solvent is not particularly limited. By adjusting the ratio of the total compounding amount of the first metal alkoxide and the second metal alkoxide (and the third metal alkoxide included as needed) to the solvent, the content (i.e., the coating amount) of the film in the magnetic particles can be controlled. Specifically, the larger the ratio of the total compounding amount, the thicker the film. On the other hand, the smaller the ratio of the total compounding amount, the thinner the film.

[0182] The solvent constituting the solvent is not particularly limited as long as it does not hinder the reaction of each metal alkoxide such as the first metal alkoxide and the second metal alkoxide (and the third metal alkoxide included as needed). For example, it is preferably a monohydric alcohol, an ether, a diol, or a glycol ether. In a preferred embodiment, the solvent can be monohydric alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, 2-methyl-2-pentanol, etc.; ethers such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, etc.; diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, etc.; glycol ethers such as dipropylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, or diethylene glycol monohexyl ether. The preferred solvent is monohydric alcohols. In addition, water can also be included as needed. The above solvents can be used alone, or two or more of them can be used.

[0183] The solvent can contain various additives, such as catalysts, pH adjusters, stabilizers, thickeners, etc. As the above additives, for example, acid compounds such as boric acid compounds and basic compounds such as ammonium salts can be cited. The solvent can usually become basic by containing ammonia or basic compounds. As long as the sol-gel reaction of the metal alkoxide proceeds, the content of the basic compound in the basic solvent is not particularly limited.

[0184] The compounding amount of the solvent during stirring is usually not particularly limited. For example, it can be 10% by weight to 100% by weight, preferably 20% by weight to 80% by weight, based on the total amount of the magnetic core and the solvent.

[0185] It is considered that by stirring the magnetic core and the specified metal alkoxide in the solvent, the sol-gel reaction of the metal alkoxide occurs on the surface of the magnetic core to form a mesh structure.

[0186] As long as each metal alkoxide is uniformly present on the surface of the magnetic core and a mesh structure is formed, the temperature of the mixture during stirring is not particularly limited. For example, it is 10°C to 70°C, preferably 15°C to 35°C.

[0187] In addition, as long as each metal alkoxide uniformly exists on the surface of the magnetic core and a mesh structure is formed, the stirring time is not particularly limited, for example, it is 10 minutes to 5 hours, preferably 30 minutes to 3 hours.

[0188] The cleaning is carried out to remove the residual catalyst. For example, it is carried out by bringing the residue generated by filtration into contact with a cleaning solvent. The cleaning solvent is not particularly limited, and for example, it can be acetone. Cleaning can be carried out, or it can also not be carried out.

[0189] By heating and drying, the solvent used in the cleaning is removed. The heating temperature is usually 15°C or higher (especially 15°C to 250°C), and from the viewpoint of removing the solvent, it is preferably 15°C to 200°C. The heating time is usually 30 minutes or longer (especially 30 minutes to 24 hours), and from the viewpoint of removing the solvent, it is preferably 60 minutes to 12 hours.

[0190] [Magnetic Core and Coil Component]

[0191] The present invention also provides a magnetic core containing the magnetic particles of the present invention described above. The magnetic core using the magnetic particles of the present invention has a high relative magnetic permeability and a high specific resistance. Therefore, when the magnetic core of the present invention is used as the magnetic core of a coil component, high electrical characteristics can be exhibited and eddy current loss can be suppressed. The magnetic core of the present invention can also be a powder compact magnetic core obtained by compression molding the magnetic particles of the present invention described above.

[0192] In addition, as Figure 4 shown, the present invention also provides a coil component 10 having the powder compact magnetic core 11 of the present invention described above and a coil 12 wound around the powder compact magnetic core. Figure 4 is a schematic front view showing a coil component using the powder compact magnetic core of the present invention.

[0193] The powder compact magnetic core 11 of the present invention can be manufactured by a method known in the art. For example, the powder compact magnetic core of the present invention can be obtained by compression molding a mixed powder in which a binding material (such as a resin (such as silicone resin)) is added to the magnetic particles of the present invention and performing heat treatment on the obtained compression molded body.

[0194] Furthermore, as Figure 5 shown, the present invention also provides a coil component 20 including a unit body 21 and a coil 22 embedded in the unit body, and the unit body 21 contains the magnetic particles and a resin (such as silicone resin) of the present invention. Figure 5 is a schematic internal perspective three-dimensional view showing another coil component using the magnetic particles of the present invention.

[0195] The coil component 20 of the present invention can be manufactured by methods well known in the art. For example, the coil component 20 of the present invention can be obtained by embedding a coil 22 in a mixed powder of magnetic particles of the present invention added with a binder material (such as a resin (such as an epoxy resin, a silicone resin)), performing compression molding, and heat-treating the obtained compression molded body.

[0196] Examples

[0197] (Example A1, Comparative Examples A1 to A3, Examples B1 to B4, and Examples C1 to C3)

[0198] Prepare 70 g of ethanol in which 10.0 g of 16 wt% ammonia water is dissolved. Add a first metal alkoxide and a second metal alkoxide to this solution so that the usage amounts for each example (or each comparative example) become the usage amounts (i.e., the amounts described in Tables 14 to 16) relative to 100 parts by weight of the magnetic core to be added later.

[0199] Next, add 30 g of a magnetic core (Fe-Si-Cr alloy) (average particle size 30 μm), and stir at 25°C for 120 minutes. Filter the reaction solution, dry the treated powder at 80°C for 120 minutes, and form an insulating film on the surface of the magnetic core. Thus, magnetic particles are obtained.

[0200] Next, mix the obtained magnetic particles with an epoxy resin as a binder (4.2 parts by weight relative to 100 parts by weight of the magnetic material), perform compression molding under a pressure of 400 MPa, and heat at 200°C for 1 hour to produce an annular core (i.e., a powder compact core) with an inner diameter of 4 mm, an outer diameter of 9 mm, and a thickness of 1 mm, and a square plate specimen of 3 mm × 3 mm × 1 mm.

[0201] (Evaluation)

[0202] · Relative permeability

[0203] For the produced annular coil, use an RF impedance analyzer (E4991A) manufactured by Agilent Technologies, Ltd. to measure the relative permeability at 1 MHz and 1 Vrms (the average value with n = 3 is shown in the table). Based on the following criteria, judge the average value of the relative permeability.

[0204] ◎◎: 35 or more (best);

[0205] ◎: 32 or more and less than 35 (excellent);

[0206] ○: 30 or more and less than 32 (good);

[0207] ×: less than 30 (unqualified).

[0208] A judgment result of “○” or above is rated as qualified.

[0209] · Specific resistance

[0210] For square plate specimens, using a high-resistance meter (R8340A ULTRAHIGH RESISTANCE METER) manufactured by Advantest Corporation, apply a DC voltage of 900 V, measure the resistance after 5 seconds, and calculate the specific resistance from the specimen size (show the average value of n = 3 in the table). Judge the average value of the specific resistance based on the following criteria.

[0211] ◎◎: 5 × 10 12 Ω·cm or more (preferably);

[0212] ◎: 1 × 1010 Ω·cm or more and less than 5 × 10 12 Ω·cm (excellent);

[0213] ○: 1 × 10 8 Ω·cm or more and less than 1 × 10 10 Ω·cm (good);

[0214] ×: less than 1 × 10 8 Ω·cm (unqualified).

[0215] A judgment result of “○” or above is rated as qualified.

[0216] · Comprehensive judgment

[0217] Based on the judgment results of relative magnetic permeability and specific resistance, make a comprehensive judgment.

[0218] ◎◎: Both judgment results are ◎◎;

[0219] ◎: The lowest judgment result among the two judgment results is ◎;

[0220] ○: The lowest judgment result among the two judgment results is ○;

[0221] ×: The lowest judgment result among the two judgment results is ×.

[0222] A comprehensive judgment result of “○” or above is rated as qualified. A comprehensive judgment result of “×” is rated as unqualified.

[0223] (Measurement)

[0224] · Average film thickness of coating 3

[0225] Measure the average film thickness of the coating using HD-2300A (Hitachi High-Technologies Corporation).

[0226]

[0227] Comparison between Example A1 and Comparative Examples A1 to A3 shows that by using a second metal alkoxide in addition to the first metal alkoxide to form a film, the compacted powder magnetic core can have both a sufficiently high relative magnetic permeability and specific resistance. Due to the slidability generated by the divalent hydrocarbon group of the second metal alkoxide, the packing property of the magnetic particles is more excellent, so a higher relative magnetic permeability can be obtained. Based on the stress relaxation property of the film obtained from the second metal alkoxide, the film has more excellent damage resistance, so a higher specific resistance can be maintained even after ring formation.

[0228] Comparative Example A1 shows that the resistance is low when only magnetic powder is used. It shows that the specific resistance decreases because there is no film.

[0229] Comparative Example A2 shows that both the relative magnetic permeability and specific resistance are low when only the first metal alkoxide is used. It is considered that the packing property of the magnetic particles is low when only the first metal alkoxide is used, so the relative magnetic permeability decreases. It is considered that the stress relaxation property of the film is low when only the first metal alkoxide is used, and the film is damaged during ring formation, so the specific resistance decreases.

[0230] Comparative Example A3 shows that both the relative magnetic permeability and specific resistance are low when only the second metal alkoxide is used. It is considered that the strength of the film is low when only the second metal alkoxide is used, and the film is damaged during ring formation, so the specific resistance decreases.

[0231]

[0232] Examples A1 and B1 to B4 show that by using the first metal alkoxide and the second metal alkoxide together, the compacted powder magnetic core can have both a sufficiently high relative magnetic permeability and specific resistance.

[0233] Comparison between Examples A1 and B1 to B2 and Examples B3 to B4 shows that if the number of carbon atoms of the divalent hydrocarbon group of the second metal alkoxide is 2 to 8, a higher relative magnetic permeability and specific resistance can be obtained.

[0234] Comparison between Example A1 and Examples B1 to B4 shows that if the number of carbon atoms of the divalent hydrocarbon group of the second metal alkoxide is 3 to 7 (especially 4 to 7), a sufficiently high relative magnetic permeability and specific resistance can be obtained.

[0235]

[0236] Examples A1 and C1 to C3 show that even if the metal of the first metal alkoxide is not Si, the compacted powder magnetic core can have both a sufficiently high relative magnetic permeability and specific resistance.

[0237] Comparison between Example A1 and C1 - C2 and Example C3 shows that if the metal of the first metal alkoxide is Si, Al or Ti, higher relative magnetic permeability and specific resistance can be obtained.

[0238] Comparison between Example A1 and Examples C1 - C3 shows that if the metal of the first metal alkoxide is Si, relatively high enough relative magnetic permeability and specific resistance can be obtained.

[0239] Industrial applicability

[0240] The magnetic particles of the present invention can be well used as a material for coil components. As such coil components, for example, inductors, chokes, etc. can be cited.

Claims

1. A magnetic particle having a core of a metallic magnetic material and a film coating the surface of the core, wherein the film contains a reaction product obtained using a first metal alkoxide and a second metal alkoxide; the first metal alkoxide is a compound represented by the following general formula (1) or a mixture thereof: M 1 (OR 1 ) x (1) In formula (1), M 1 is Li, Na, Mg, K, Ca, Cu, Sr, Y, Ba, Ce, Ta, Bi, Si, Ti, Al or Zr; x is the valence of M 1 and is an integer from 1 to 4; R 1 is independently an alkyl group having 1 to 10 carbon atoms or -C(R 2 )=CH-CO-R 3 , wherein R 2 is an alkyl group having 1 to 10 carbon atoms, R 3 is an alkyl group having 1 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms or an alkenyloxy group having 1 to 30 carbon atoms; in R 1 , when two adjacent R 1 are the said alkyl groups, they are bonded to each other and together with the oxygen atom to which these two R 1 are bonded and the M 1 atom to which this oxygen atom is bonded form a ring or do not form a ring; the second metal alkoxide is a compound represented by the following general formula (2A) or a mixture thereof: (R 211 )(O)3Si-R 31 -Si(OR 212 )3 (2A) In formula (2A), R 211 and R 212 are each independently an alkyl group having 1 to 10 carbon atoms; R 31 is a divalent hydrocarbon group having 1 to 20 carbon atoms.

2. The magnetic particles according to claim 1, wherein, In the general formula (2A), R 31 is a divalent hydrocarbon group having 1 to 10 carbon atoms.

3. The magnetic particles according to claim 2, wherein, In the general formula (2A), R 31 is a divalent hydrocarbon group having 2 to 8 carbon atoms.

4. The magnetic particles according to claim 1 or 2, wherein the film contains a reaction product prepared using 5 wt% to 95 wt% of the first metal alkoxide and 5 wt% to 95 wt% of the second metal alkoxide, and the weight ratio is based on a total weight of 100 wt% of the first metal alkoxide and the second metal alkoxide.

5. The magnetic particles according to claim 1 or 2, wherein, The film has an average thickness of 1 nm to 100 nm.

6. The magnetic particles according to claim 1 or 2, wherein The metallic magnetic material contains Fe.

7. The magnetic particles according to claim 1 or 2, wherein, The metallic magnetic material is Fe, an Fe-Si alloy, an Fe-Si-Cr alloy, an Fe-Al alloy, an Fe-Si-Al alloy, or an Fe-Ni alloy.

8. A method for manufacturing a magnetic particle, comprising: mixing a core of a metallic magnetic material, a first metal alkoxide, a second metal alkoxide, and a solvent, hydrolyzing and drying the first metal alkoxide and the second metal alkoxide to obtain a magnetic particle having a core of a metallic magnetic material and a film coating the surface of the core; wherein the first metal alkoxide is a compound represented by the following general formula (1) or a mixture thereof: M 1 (OR 1 ) x (1) In formula (1), M 1 is Li, Na, Mg, K, Ca, Cu, Sr, Y, Ba, Ce, Ta, Bi, Si, Ti, Al or Zr; x is the valence of M 1 and is an integer from 1 to 4; R 1 is independently an alkyl group having 1 to 10 carbon atoms or -C(R 2 )=CH-CO-R 3 , wherein R 2 is an alkyl group having 1 to 10 carbon atoms, R 3 is an alkyl group having 1 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms or an alkenyloxy group having 1 to 30 carbon atoms; in R 1 , when two adjacent R 1 are the said alkyl groups, they are bonded to each other and together with the oxygen atom to which these two R 1 are bonded and the M 1 atom to which this oxygen atom is bonded form a ring or do not form a ring; the second metal alkoxide is a compound represented by the following general formula (2A) or a mixture thereof: (R 211 O)3Si-R 31 -Si(OR 212 )3 (2A) In formula (2A), R 211 and R 212 are each independently an alkyl group having 1 to 10 carbon atoms; R 31 is a divalent hydrocarbon group having 1 to 20 carbon atoms.

9. The method for manufacturing magnetic particles according to claim 8, wherein, In the general formula (2A), R 31 is a divalent hydrocarbon group having 1 to 10 carbon atoms.

10. The method for manufacturing magnetic particles according to claim 9, wherein, In the general formula (2A), R 31 is a divalent hydrocarbon group having 2 to 8 carbon atoms.

11. The method for manufacturing magnetic particles according to claim 8 or 9, wherein, when mixing the first metal alkoxide and the second metal alkoxide, the weight ratio of the second metal alkoxide is 5 wt% to 95 wt% based on a total weight of 100 wt% of the first metal alkoxide and the second metal alkoxide.

12. The method for manufacturing magnetic particles according to claim 8 or 9, wherein, The film has an average thickness of 1 nm to 100 nm.

13. The method for manufacturing magnetic particles according to claim 8 or 9, wherein, The metallic magnetic material contains Fe.

14. The method for manufacturing magnetic particles according to claim 8 or 9, wherein, The metallic magnetic material is Fe, an Fe-Si alloy, an Fe-Si-Cr alloy, an Fe-Al alloy, an Fe-Si-Al alloy, or an Fe-Ni alloy.

15. A magnetic core comprising the magnetic particle according to any one of claims 1 to 7.

16. A coil component having the magnetic core of claim 15 and a coil wound around the magnetic core.

17. A coil component having a unit body and a coil embedded in the unit body, the unit body containing the magnetic particle according to any one of claims 1 to 7 and a resin.

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