CA1340795C - Magnetic ribbon and magnetic core - Google Patents
Magnetic ribbon and magnetic coreInfo
- Publication number
- CA1340795C CA1340795C CA000596211A CA596211A CA1340795C CA 1340795 C CA1340795 C CA 1340795C CA 000596211 A CA000596211 A CA 000596211A CA 596211 A CA596211 A CA 596211A CA 1340795 C CA1340795 C CA 1340795C
- Authority
- CA
- Canada
- Prior art keywords
- ribbon
- magnetic
- fine particles
- magnetic ribbon
- attached
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0206—Manufacturing of magnetic cores by mechanical means
- H01F41/0213—Manufacturing of magnetic circuits made from strip(s) or ribbon(s)
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
- H01F1/147—Alloys characterised by their composition
- H01F1/153—Amorphous metallic alloys, e.g. glassy metals
- H01F1/15383—Applying coatings thereon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
- H01F1/16—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets
- H01F1/18—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets with insulating coating
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/24—Magnetic cores
- H01F27/25—Magnetic cores made from strips or ribbons
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Soft Magnetic Materials (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
- Magnetic Heads (AREA)
- Magnetic Record Carriers (AREA)
- Decoration Of Textiles (AREA)
Abstract
Disclosed are a magnetic ribbon on at least one surface of which fine particles formed of a nonmagnetic inorganic substance having insulating properties are attached and a magnetic core around which this magnetic ribbon is wound or on which it is laminated. The fine particles serve as a spacer to form a layer of air between adjacent layers of the magnetic ribbon.
Description
1340'~~~
MAGNETIC RIBBON AND MAGNETIC CORE
BACKGROUND OF THE INVENTION:
The present invention relates to a magnetic ribbon and a magnetic core formed by using said magnetic ribbon.
If a magnetic core is formed by winding or laminating a magnetic ribbon, and if insulation between layers of the ribbon is poor, an eddy current flowing across the ribbon layers occurs and an increase in eddy current losses results in an increase in overall core losses (magnetic losses). This tendency is particularly noticeable in the case of high frequencies. In addition, the frequency characteristics of permeability is poor, and it is impossible to expect any advantageous use at 100 kHz or more.
Accordingly, in order to improve insulation between ribbon layers, an insulating layer formed of a nonmagnetic material is conventionally provided between the ribbon layers, and a uniform insulating film is formed on the ribbon surface as one means thereof, so as to solve the aforementioned problem.
In cases where an amorphous magnetic ribbon is processed as a magnetic ribbon, annealing is usually carried out at 400oC or thereabouts. However, if such annealing is carried out, because of a difference in the coefficient of linear expansion, i.e., since the coefficient of linear expansion ,.
~.3~Or19~
of the insulating film is greater than that of the amorphous ribbon, compressive stress occurs in the ribbon, and magnetic characteristics deteriorate due to the adverse effect of magnetostriction.
In addition, there is another problem in that materials of such insulating films capable of withstanding annealing at 400°C or thereabouts are limited. Furthermore, if a magnetic core is formed by providing an insulating film, the filling factor (space factor) declines, which disadvantageously causes the magnetic core to become large in size.
SUMMARY OF THE INVENTION:
Accordingly, an object of the present invention is to provide a magnetic ribbon and a magnetic core having excellent magnetic characteristics while securing insulating properties between ribbon layers with a minimum decline in the space factor, thereby overcoming the above-described drawbacks of the conventional art.
The present invention has been devised by first paying attention to the following point which serves as a theoretical premise.
As described above, at the time of producing a magnetic core by using a magnetic ribbon, an insulating film is generally interposed between ribbon layers, and the greatest matter of concern to those skilled in the art lies in finding an insulating material having an excellent insulating performance.
1340~~~
However, when viewed from a different perspective, even if such an insulating film is not present, if air a.s present between the layers, air would serve as an insulating layer and prevent an eddy current, and the space factor could be made as large as possible.
Therefore, in accordance with the present invention, there are provided a magnetic ribbon on at least one side of which fine particles formed of a nonmagnetic inorganic substance having insulating properties are attached so coarsely that an insulating layer of air is formed between adjacent magnetic ribbons, as well as a magnetic core having the ribbon wound therearound or laminated thereon.
In the present invention, the fine particles are attached so coarsely as to secure an insulating layer of air.
In accordance with the present invention, fine particles formed of an inorganic substance are attached on at least one surface of the magnetic ribbon, so that if the magnetic ribbon is wound or laminated to form a magnetic core, the fine particles serve as a spacer, thereby forming a layer of air between adjacent layers of the ribbon.
According to a broad aspect of the invention there is provided a magnetic ribbon for winding or lamination into a magnetic core, the magnetic ribbon being formed of an amorphous metal and having coated on at least one surface thereof fine particles of 10 nm to 2 ~,m in size formed of a nonmagnetic metal oxide having electrically-insulating properties, the fine particles being attached to the surface in an amount of 10-~ cm3 to 2 x 10-4 cm3 per square centimeter ,C
~~4C~'~1~~
of surface area so coarsely that an insulating layer of air is formed between adjacent magnetic ribbon layers when the magnetic ribbon is wound or laminated.
According to another broad aspect of the invention there is provided a process for manufacturing a magnetic ribbon comprising the steps of:
a) coating a fine particles-containing dispersion on at least one surface of an amorphous metal ribbon, the particles being 10 nm to 2 ~.m in size formed of a nonmagnetic metal oxide having electrically-insulating properties, so as to attach the particles to the surface in an amount of 10-~ cm3 to 2 x 10-4 cm3 per square centimeter of surface area so coarsely that an insulating layer of air is formed between adjacent magnetic ribbon layers when the magnetic ribbon is wound or laminated;
b) drying the coated ribbon; and c) annealing the dried coated ribbon for 0.5 to 5 hours at a temperature of 300 to 500°C in an inert gas atmosphere.
According to another broad aspect of the invention there is provided a process for manufacturing a magnetic core comprising the steps of:
a) winding or laminating a magnetic ribbon, the magnetic ribbon being formed of an amorphous metal and having coated on at least one surface thereof fine particles of 10 nm to 2 ~,m in size formed of a nonmagnetic metal oxide having electrically-insulating properties, the fine particles being attached to the surface in an amount of 10-~ cm3 to 2 x 10-4 cm3 per square centimeter of surface area so coarsely that an C
.. 13~0'~~~
insulating layer of air is formed between adjacent magnetic ribbon layers; and b) annealing the wound or laminated magnetic ribbon for 0.5 to 5 hours at a temperature of 300 to 500°C in an inert gas atmosphere.
BRIEF DESCRIPTION OF THE DRAWINGS:
Figures 1 to 3 are graphs illustrating magnetic characteristics in accordance with a first embodiment of the present invention, in which Figure 1 illustrates B-H characteristics;
Figure 2 illustrates the frequency characteristics of core loss; and Figure 3 illustrates the frequency characteristics of permeability.
Figures 4 to 6 are graphs illustrating the magnetic characteristics in accordance with a second embodiment of the present invention, in which - 4a -13407~~
Fig. 4 illustrates H-H characteristics;
Fig. 5 illustrates the frequency characteristics of core loss; and Fig. 6 illustrates the frequency characteristics of permeability; and Fig. 7 illustrates the outiine of apparatus for attaching finearticles: and Fig. g is a diagram schematically illustrating means for producing a toroidai type magnetic core.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
Referring now to the accompanying drawings, a description will be given of the preferred embodiments of the present invention.
The magnetic ribbon referred to in the present invention is a thin magnetic strip, and, as magnetic materials, it is possible to cite the following:
ferromagnetic elements such as Fe, Co, and Ni among transition metals, alloys of ferromagnetic elements, alloys of ferromagnetic elements and nonferromagnetic elements which are added to improve characteristics, ferrite, permalloy, amorphous alloys, etc. As amorphous alloys, it is possible to cite Fe-based alloys such as Fe-H, Fe-H-C, Fe-H-Si, Fe-H-Si-C, Fe-B-Si-Cr, Fe-Co-B-Si, and Fe-Ni-Mo-B, Co-based alloys such as Co-B, Co-Fe-Si-B, Co-Fe-Ni-Mo-B-Si, Co-Fe-Ni-B-Si, Co-Fe-Mn-H-Si, Co-Fe-Mn-Ni, Co-Mn-Ni-H-Si, and Co-Fe-Mn-Ni-B, and other similar alloys.
The conditions of inorganic fine particles that are attached to such a magnetic ribbon are that it is nonmagnetic, and that it has insulating properties. If the fine particles are magnetic and conductive. an adverse effect is exerted on magnetic characteristics, and an eddy current is liable to flow.
As inorganic substances used in the present invention, it is possible to cite the following: (1) inorganic substances which are stable in a natural condition, including glass (sodium silicate), mica (aluminosilicate alkali salt and phyllosilicate alkali salt), silicon carbide, calcium sulfate semi-water salt, potassium carbonate, magnesium carbonate, calcium carbonate, barium sulfate, and the like; (2) metal oxides such as aluminum oxide, boron oxide, magnesium oxide, silicon dioxide. tin dioxide, zinc oxide, zirconium dioxide, antimony pentoxide, and the like; and (3) ceramics formed of the materials cited in (2) above and double oxides such as perovskite, silicate glass, phosphate, titanic acid salt, niobium, tantalum, and tungstate; ceramics formed singly or in a combination by using such ceramic materials as nitrides, including aluminum nitride, a sintered body of aluminum oxide and nitride, boron nitride, boron nitride magnesium, boron nitride complexes, silicon nitride, silicon nitride lanthanum, and SIALON; carbides, including boron carbide, Trade-mark 1340 ~~5 silicon carbide, boron carbide aluminum, and titanium carbide, and borides, including titanium diboride, calcium hexaboride, and lanthanum hexaboride. Among these substances, antimony pentoxide is preferably used.
As for the size of the fine particles of the inorganic substance, if consideration is paid to the fact that the fine particles are attached to the ribbon uniformly so as to form an insulating layer, the size of the fine particles may be small. However, if the particle size is made too small, it constitutes a factor making manufacture difficult. Meanwhile, if the particle size is too large, when the magnetic core is formed by a ribbon, the gap between the adjacent layers of the ribbon becomes too large, so that the space factor of the magnetic material becomes small. For this reason, it is preferred that the size of the fine particles is set in the range of 10 nm to 2 pm.
In addition, as for the amount of the fine particles attached, the fine particles may preferably be attached in such a manner that they are attached by 10-~cm3 to 2 x 10-4cm3, more preferably 3 x 10-6cm3 - 10-5cm3, per unit area (1 cm2). If this amount attached is calculated into the weight of fine particles per unit area, although its value changes depending on the specific weight of the material of the fine particles, in the case of antimony pentoxide, the 1340~g~
weight is 3.8 x 10-~g/cm2 - 7.6 x 10-Qg/cm2, preferably 1.1 x 10-5g/cm2 - 3.8 x 10-5g/cm2.
Means for attaching the fine particles is so arranged that these fine particles are dispersed in water or a volatile organic solvent such as toluene, and, after this solution is applied to the ribbon surface, force or natural drying is carried out, thereby allowing the fine particles to be attached to the ribbon. The concentration of this solution determines the amount of fine particles to be attached to the ribbon. In other words, in the case of antimony pentoxide, this inorganic substance may be dispersed in toluene in a colloidal state at a rate of from 0.1 to 30 wt% with respect to toluene. 3 wt% or thereabouts in this range is also effective, a decline in the space factor is practically nil, and the magnetic characteristics do not deteriorate. The thickness of the film of the solution applied is preferably 10 pm or less in determining the aforementioned amount of fine particles to be attached. In addition, a drying furnace may be used for evaporation of the solvent depending on the solvent, and drying may be carried out at 100~C or above.
With respect to the magnetic ribbon, or an amorphous ribbon, in particular, annealing may be carried out for 0.
- 5 hours at the temperature of 300 - SOOoC in an inert gas atmosphere such as nitrogen so as to eliminate strain, _g_ 1340~9~
as required. This annealing may be effected after the ribbon is wound or laminated into a magnetic core, or may be effected in the state of the ribbon. In particular, when annealing is effected at a temperature 10 to 50°C higher than the Curie point, a magnetic core exhibiting excellent characteristics with respect to high frequencies can be obtained.
Incidentally, annealing may be effected in a magnetic field or in a nonmagnetic field.
In addition, when the amorphous magnetic core with the ribbon wound therearound or laminated thereon is annealed since the fine particles disposed between adjacent ribbon layers are powders, the magnetic core is not subjected to linear expansion. The fine particles rather exhibit the action or absorbing the stress accompanying the shrinkage of the amorphous ribbon.
On the basis of the foregoing, a description will now be given of a method of producing a magnetic core in accordance with the present invention.
First, a magnetic ribbon and a dispersion containing fine particles are prepared. The dispersion containing the fine particles is applied to at least one surface of the magnetic ribbon by any of the various methods of application, and the solvent is allowed to dry. The resultant magnetic ribbon with the fine particles attached thereto is wound under tension, thereby obtaining a toroidal-type magnetic _ g _ ,C
13~0'~~5 core. Finally, annealing for eliminating strain is carried out, as necessary. Incidentally, tension applied at the time of winding is preferably 0.05 to 2 kg.
Meanwhile, when a laminated type magnetic core is produced, the ribbon with fine particles attached thereto is cut into a predetermined configuration, and the cut pieces are laminated so as to form the magnetic core. Annealing which is carried out as necessary may be effected prior to the lamination or after the magnetic core has been formed subsequent to the lamination. The thus obtained magnetic core can be preferably used particulary for electrical or electronic devices such as choke coils, transformers, inductors and the like.
Examples of the present invention will be described hereafter.
By using the apparatus shown in Figure 7, an amorphous ribbon la (26055-2, Fe78-B13-Sig, 10 mm width) made by Allied Corp. is fed forward into a colloidal solution 2 of antimony pentoxide. When the amorphous ribbon 1a is lifted up, the amorphous ribbon 1a is clamped by a pair of bar coaters 3 so as to allow excess solution to drop. Then, while the ribbon la is being dried with hot air by means of a hot air drier 4, the ribbon la was taken up. As for the colloidal solution 2 of antimony pentoxide, toluene was used as the solvent, and 3 wto of antimony was dispersed with respect to toluene 97 wto.
Subsequently, as shown in Figure 8, the ribbon 1b with the particles attached thereto was fed forward via rollers 5, and was wound under tension in a final stage, thereby forming an amorphous magnetic core 6. A plurality of magnetic cores having the same dimensions were then formed, and were subjected to annealing for two hours at 435oC in a nitrogen atmosphere.
With respect to the magnetic cores thus obtained, measurements were made of the B-H characteristics, frequency characteristics of core loss, and frequency characteristics of permeability. As for the B-H
characteristics, measurements were made of two cases: one in which a magnetic field of 10 oersted (Oe), and the other in which a magnetic field of 1 oersted (Oe) was applied.
In addition, a colloidal solution in which 30 wt% of antimony pentoxide was dispersed with respect to 70 wt% of toluene was applied to the ribbon la, and measurements were similarly made. The detailed conditions in the respective examples were as follows:
(1) Example 1 (3 wt% solution) (a) Magnetic core: a toroidal core with the aforementioned ribbon wound therearound Inside diameter: 23.00 mm Outside diameter: 37.00 mm Height: 10.00 mm Mass: 42.00 g Density of the material: 7.18 g/m3 .~34019~
Volume: 5.850 x 10-6 {m3) Effective sectional area: 6.207 x 10-5 (mz) Mean magnetic path length: 9.425 x 10-2 (m) Space factor: 88.67% (ratio of the volume of the ribbon to the total volume) Tension during the magnetic ribbon winding: 0.8 kg (b) Colloidal solution applied Organic solvent: toluene, 100 wt%
Fine particles: antimony pentoxide, 3 wt~
(c) Results * B-H characteristics are shown in Fig. 1.
* Frequency characteristics of core loss are shown in Fig. 2.
The number of turns of the primary winding around the core was 5, while the number of turns of the secondary winding was 10.
* Frequency characteristics of permeability are shown in Fig. 3.
The number of turns of the primary winding around the core was 10.
Measured magnetic field: 5 mOe Measured current: 2.65173 mA
(2) Example 2 (3pwt% solution) (a) Magnetic core: a toroidal core with the aforementioned ribbon wound therearound I3~~~~5 Inside diameter: 23.00 mm Outside diameter: 37.00 mm Height: 10.00 mm Mass: 25.57 g Density of the material: 7.18 g/m3 Volume: 3.561 x 10-6 (m3) Effective sectional area: 3.779 x 10-5 (m2) Mean magnetic path length: 9.425 x 10-2 (m) Space factor: 53.98 Tension during the magnetic ribbon winding: 0.8 kg (b) Colloidal solution applied Organic solvent: toluene, 70 wt~
Fine particles: antimony pentoxide, 30 wt~
(c) Results * B-H characteristics are shown in Fig. 4.
* Frequency characteristics of core loss are shown in Fig. 5.
The number of turns of the primary winding around the core was 5, while the number of turns of the secondary winding was 10.
* Frequency characteristics of permeability are shown in Fig. 6.
The number of turns of the primary winding around the core was 10.
Measured magnetic field: 5 mOe 13407~~
Measured current: 2.65173 mA
From the foregoing results, it can be appreciated that the magnetic cores of the Examples display a hysteresis which is closer to a linear configuration, and that the core loss is low as a whole, and a rise in the high-frequency component can be reduced to a low level. A
substantially fixed permeability was obtained up to 200 kHz.
As described above, in accordance with the present invention, since the above-described arrangement is adopted, it is possible to improve the magnetic characteristics at a frequency higher than 10 kHz, and the space factor can be made as large as possible, thereby making contributions to making the magnetic core compact.
MAGNETIC RIBBON AND MAGNETIC CORE
BACKGROUND OF THE INVENTION:
The present invention relates to a magnetic ribbon and a magnetic core formed by using said magnetic ribbon.
If a magnetic core is formed by winding or laminating a magnetic ribbon, and if insulation between layers of the ribbon is poor, an eddy current flowing across the ribbon layers occurs and an increase in eddy current losses results in an increase in overall core losses (magnetic losses). This tendency is particularly noticeable in the case of high frequencies. In addition, the frequency characteristics of permeability is poor, and it is impossible to expect any advantageous use at 100 kHz or more.
Accordingly, in order to improve insulation between ribbon layers, an insulating layer formed of a nonmagnetic material is conventionally provided between the ribbon layers, and a uniform insulating film is formed on the ribbon surface as one means thereof, so as to solve the aforementioned problem.
In cases where an amorphous magnetic ribbon is processed as a magnetic ribbon, annealing is usually carried out at 400oC or thereabouts. However, if such annealing is carried out, because of a difference in the coefficient of linear expansion, i.e., since the coefficient of linear expansion ,.
~.3~Or19~
of the insulating film is greater than that of the amorphous ribbon, compressive stress occurs in the ribbon, and magnetic characteristics deteriorate due to the adverse effect of magnetostriction.
In addition, there is another problem in that materials of such insulating films capable of withstanding annealing at 400°C or thereabouts are limited. Furthermore, if a magnetic core is formed by providing an insulating film, the filling factor (space factor) declines, which disadvantageously causes the magnetic core to become large in size.
SUMMARY OF THE INVENTION:
Accordingly, an object of the present invention is to provide a magnetic ribbon and a magnetic core having excellent magnetic characteristics while securing insulating properties between ribbon layers with a minimum decline in the space factor, thereby overcoming the above-described drawbacks of the conventional art.
The present invention has been devised by first paying attention to the following point which serves as a theoretical premise.
As described above, at the time of producing a magnetic core by using a magnetic ribbon, an insulating film is generally interposed between ribbon layers, and the greatest matter of concern to those skilled in the art lies in finding an insulating material having an excellent insulating performance.
1340~~~
However, when viewed from a different perspective, even if such an insulating film is not present, if air a.s present between the layers, air would serve as an insulating layer and prevent an eddy current, and the space factor could be made as large as possible.
Therefore, in accordance with the present invention, there are provided a magnetic ribbon on at least one side of which fine particles formed of a nonmagnetic inorganic substance having insulating properties are attached so coarsely that an insulating layer of air is formed between adjacent magnetic ribbons, as well as a magnetic core having the ribbon wound therearound or laminated thereon.
In the present invention, the fine particles are attached so coarsely as to secure an insulating layer of air.
In accordance with the present invention, fine particles formed of an inorganic substance are attached on at least one surface of the magnetic ribbon, so that if the magnetic ribbon is wound or laminated to form a magnetic core, the fine particles serve as a spacer, thereby forming a layer of air between adjacent layers of the ribbon.
According to a broad aspect of the invention there is provided a magnetic ribbon for winding or lamination into a magnetic core, the magnetic ribbon being formed of an amorphous metal and having coated on at least one surface thereof fine particles of 10 nm to 2 ~,m in size formed of a nonmagnetic metal oxide having electrically-insulating properties, the fine particles being attached to the surface in an amount of 10-~ cm3 to 2 x 10-4 cm3 per square centimeter ,C
~~4C~'~1~~
of surface area so coarsely that an insulating layer of air is formed between adjacent magnetic ribbon layers when the magnetic ribbon is wound or laminated.
According to another broad aspect of the invention there is provided a process for manufacturing a magnetic ribbon comprising the steps of:
a) coating a fine particles-containing dispersion on at least one surface of an amorphous metal ribbon, the particles being 10 nm to 2 ~.m in size formed of a nonmagnetic metal oxide having electrically-insulating properties, so as to attach the particles to the surface in an amount of 10-~ cm3 to 2 x 10-4 cm3 per square centimeter of surface area so coarsely that an insulating layer of air is formed between adjacent magnetic ribbon layers when the magnetic ribbon is wound or laminated;
b) drying the coated ribbon; and c) annealing the dried coated ribbon for 0.5 to 5 hours at a temperature of 300 to 500°C in an inert gas atmosphere.
According to another broad aspect of the invention there is provided a process for manufacturing a magnetic core comprising the steps of:
a) winding or laminating a magnetic ribbon, the magnetic ribbon being formed of an amorphous metal and having coated on at least one surface thereof fine particles of 10 nm to 2 ~,m in size formed of a nonmagnetic metal oxide having electrically-insulating properties, the fine particles being attached to the surface in an amount of 10-~ cm3 to 2 x 10-4 cm3 per square centimeter of surface area so coarsely that an C
.. 13~0'~~~
insulating layer of air is formed between adjacent magnetic ribbon layers; and b) annealing the wound or laminated magnetic ribbon for 0.5 to 5 hours at a temperature of 300 to 500°C in an inert gas atmosphere.
BRIEF DESCRIPTION OF THE DRAWINGS:
Figures 1 to 3 are graphs illustrating magnetic characteristics in accordance with a first embodiment of the present invention, in which Figure 1 illustrates B-H characteristics;
Figure 2 illustrates the frequency characteristics of core loss; and Figure 3 illustrates the frequency characteristics of permeability.
Figures 4 to 6 are graphs illustrating the magnetic characteristics in accordance with a second embodiment of the present invention, in which - 4a -13407~~
Fig. 4 illustrates H-H characteristics;
Fig. 5 illustrates the frequency characteristics of core loss; and Fig. 6 illustrates the frequency characteristics of permeability; and Fig. 7 illustrates the outiine of apparatus for attaching finearticles: and Fig. g is a diagram schematically illustrating means for producing a toroidai type magnetic core.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
Referring now to the accompanying drawings, a description will be given of the preferred embodiments of the present invention.
The magnetic ribbon referred to in the present invention is a thin magnetic strip, and, as magnetic materials, it is possible to cite the following:
ferromagnetic elements such as Fe, Co, and Ni among transition metals, alloys of ferromagnetic elements, alloys of ferromagnetic elements and nonferromagnetic elements which are added to improve characteristics, ferrite, permalloy, amorphous alloys, etc. As amorphous alloys, it is possible to cite Fe-based alloys such as Fe-H, Fe-H-C, Fe-H-Si, Fe-H-Si-C, Fe-B-Si-Cr, Fe-Co-B-Si, and Fe-Ni-Mo-B, Co-based alloys such as Co-B, Co-Fe-Si-B, Co-Fe-Ni-Mo-B-Si, Co-Fe-Ni-B-Si, Co-Fe-Mn-H-Si, Co-Fe-Mn-Ni, Co-Mn-Ni-H-Si, and Co-Fe-Mn-Ni-B, and other similar alloys.
The conditions of inorganic fine particles that are attached to such a magnetic ribbon are that it is nonmagnetic, and that it has insulating properties. If the fine particles are magnetic and conductive. an adverse effect is exerted on magnetic characteristics, and an eddy current is liable to flow.
As inorganic substances used in the present invention, it is possible to cite the following: (1) inorganic substances which are stable in a natural condition, including glass (sodium silicate), mica (aluminosilicate alkali salt and phyllosilicate alkali salt), silicon carbide, calcium sulfate semi-water salt, potassium carbonate, magnesium carbonate, calcium carbonate, barium sulfate, and the like; (2) metal oxides such as aluminum oxide, boron oxide, magnesium oxide, silicon dioxide. tin dioxide, zinc oxide, zirconium dioxide, antimony pentoxide, and the like; and (3) ceramics formed of the materials cited in (2) above and double oxides such as perovskite, silicate glass, phosphate, titanic acid salt, niobium, tantalum, and tungstate; ceramics formed singly or in a combination by using such ceramic materials as nitrides, including aluminum nitride, a sintered body of aluminum oxide and nitride, boron nitride, boron nitride magnesium, boron nitride complexes, silicon nitride, silicon nitride lanthanum, and SIALON; carbides, including boron carbide, Trade-mark 1340 ~~5 silicon carbide, boron carbide aluminum, and titanium carbide, and borides, including titanium diboride, calcium hexaboride, and lanthanum hexaboride. Among these substances, antimony pentoxide is preferably used.
As for the size of the fine particles of the inorganic substance, if consideration is paid to the fact that the fine particles are attached to the ribbon uniformly so as to form an insulating layer, the size of the fine particles may be small. However, if the particle size is made too small, it constitutes a factor making manufacture difficult. Meanwhile, if the particle size is too large, when the magnetic core is formed by a ribbon, the gap between the adjacent layers of the ribbon becomes too large, so that the space factor of the magnetic material becomes small. For this reason, it is preferred that the size of the fine particles is set in the range of 10 nm to 2 pm.
In addition, as for the amount of the fine particles attached, the fine particles may preferably be attached in such a manner that they are attached by 10-~cm3 to 2 x 10-4cm3, more preferably 3 x 10-6cm3 - 10-5cm3, per unit area (1 cm2). If this amount attached is calculated into the weight of fine particles per unit area, although its value changes depending on the specific weight of the material of the fine particles, in the case of antimony pentoxide, the 1340~g~
weight is 3.8 x 10-~g/cm2 - 7.6 x 10-Qg/cm2, preferably 1.1 x 10-5g/cm2 - 3.8 x 10-5g/cm2.
Means for attaching the fine particles is so arranged that these fine particles are dispersed in water or a volatile organic solvent such as toluene, and, after this solution is applied to the ribbon surface, force or natural drying is carried out, thereby allowing the fine particles to be attached to the ribbon. The concentration of this solution determines the amount of fine particles to be attached to the ribbon. In other words, in the case of antimony pentoxide, this inorganic substance may be dispersed in toluene in a colloidal state at a rate of from 0.1 to 30 wt% with respect to toluene. 3 wt% or thereabouts in this range is also effective, a decline in the space factor is practically nil, and the magnetic characteristics do not deteriorate. The thickness of the film of the solution applied is preferably 10 pm or less in determining the aforementioned amount of fine particles to be attached. In addition, a drying furnace may be used for evaporation of the solvent depending on the solvent, and drying may be carried out at 100~C or above.
With respect to the magnetic ribbon, or an amorphous ribbon, in particular, annealing may be carried out for 0.
- 5 hours at the temperature of 300 - SOOoC in an inert gas atmosphere such as nitrogen so as to eliminate strain, _g_ 1340~9~
as required. This annealing may be effected after the ribbon is wound or laminated into a magnetic core, or may be effected in the state of the ribbon. In particular, when annealing is effected at a temperature 10 to 50°C higher than the Curie point, a magnetic core exhibiting excellent characteristics with respect to high frequencies can be obtained.
Incidentally, annealing may be effected in a magnetic field or in a nonmagnetic field.
In addition, when the amorphous magnetic core with the ribbon wound therearound or laminated thereon is annealed since the fine particles disposed between adjacent ribbon layers are powders, the magnetic core is not subjected to linear expansion. The fine particles rather exhibit the action or absorbing the stress accompanying the shrinkage of the amorphous ribbon.
On the basis of the foregoing, a description will now be given of a method of producing a magnetic core in accordance with the present invention.
First, a magnetic ribbon and a dispersion containing fine particles are prepared. The dispersion containing the fine particles is applied to at least one surface of the magnetic ribbon by any of the various methods of application, and the solvent is allowed to dry. The resultant magnetic ribbon with the fine particles attached thereto is wound under tension, thereby obtaining a toroidal-type magnetic _ g _ ,C
13~0'~~5 core. Finally, annealing for eliminating strain is carried out, as necessary. Incidentally, tension applied at the time of winding is preferably 0.05 to 2 kg.
Meanwhile, when a laminated type magnetic core is produced, the ribbon with fine particles attached thereto is cut into a predetermined configuration, and the cut pieces are laminated so as to form the magnetic core. Annealing which is carried out as necessary may be effected prior to the lamination or after the magnetic core has been formed subsequent to the lamination. The thus obtained magnetic core can be preferably used particulary for electrical or electronic devices such as choke coils, transformers, inductors and the like.
Examples of the present invention will be described hereafter.
By using the apparatus shown in Figure 7, an amorphous ribbon la (26055-2, Fe78-B13-Sig, 10 mm width) made by Allied Corp. is fed forward into a colloidal solution 2 of antimony pentoxide. When the amorphous ribbon 1a is lifted up, the amorphous ribbon 1a is clamped by a pair of bar coaters 3 so as to allow excess solution to drop. Then, while the ribbon la is being dried with hot air by means of a hot air drier 4, the ribbon la was taken up. As for the colloidal solution 2 of antimony pentoxide, toluene was used as the solvent, and 3 wto of antimony was dispersed with respect to toluene 97 wto.
Subsequently, as shown in Figure 8, the ribbon 1b with the particles attached thereto was fed forward via rollers 5, and was wound under tension in a final stage, thereby forming an amorphous magnetic core 6. A plurality of magnetic cores having the same dimensions were then formed, and were subjected to annealing for two hours at 435oC in a nitrogen atmosphere.
With respect to the magnetic cores thus obtained, measurements were made of the B-H characteristics, frequency characteristics of core loss, and frequency characteristics of permeability. As for the B-H
characteristics, measurements were made of two cases: one in which a magnetic field of 10 oersted (Oe), and the other in which a magnetic field of 1 oersted (Oe) was applied.
In addition, a colloidal solution in which 30 wt% of antimony pentoxide was dispersed with respect to 70 wt% of toluene was applied to the ribbon la, and measurements were similarly made. The detailed conditions in the respective examples were as follows:
(1) Example 1 (3 wt% solution) (a) Magnetic core: a toroidal core with the aforementioned ribbon wound therearound Inside diameter: 23.00 mm Outside diameter: 37.00 mm Height: 10.00 mm Mass: 42.00 g Density of the material: 7.18 g/m3 .~34019~
Volume: 5.850 x 10-6 {m3) Effective sectional area: 6.207 x 10-5 (mz) Mean magnetic path length: 9.425 x 10-2 (m) Space factor: 88.67% (ratio of the volume of the ribbon to the total volume) Tension during the magnetic ribbon winding: 0.8 kg (b) Colloidal solution applied Organic solvent: toluene, 100 wt%
Fine particles: antimony pentoxide, 3 wt~
(c) Results * B-H characteristics are shown in Fig. 1.
* Frequency characteristics of core loss are shown in Fig. 2.
The number of turns of the primary winding around the core was 5, while the number of turns of the secondary winding was 10.
* Frequency characteristics of permeability are shown in Fig. 3.
The number of turns of the primary winding around the core was 10.
Measured magnetic field: 5 mOe Measured current: 2.65173 mA
(2) Example 2 (3pwt% solution) (a) Magnetic core: a toroidal core with the aforementioned ribbon wound therearound I3~~~~5 Inside diameter: 23.00 mm Outside diameter: 37.00 mm Height: 10.00 mm Mass: 25.57 g Density of the material: 7.18 g/m3 Volume: 3.561 x 10-6 (m3) Effective sectional area: 3.779 x 10-5 (m2) Mean magnetic path length: 9.425 x 10-2 (m) Space factor: 53.98 Tension during the magnetic ribbon winding: 0.8 kg (b) Colloidal solution applied Organic solvent: toluene, 70 wt~
Fine particles: antimony pentoxide, 30 wt~
(c) Results * B-H characteristics are shown in Fig. 4.
* Frequency characteristics of core loss are shown in Fig. 5.
The number of turns of the primary winding around the core was 5, while the number of turns of the secondary winding was 10.
* Frequency characteristics of permeability are shown in Fig. 6.
The number of turns of the primary winding around the core was 10.
Measured magnetic field: 5 mOe 13407~~
Measured current: 2.65173 mA
From the foregoing results, it can be appreciated that the magnetic cores of the Examples display a hysteresis which is closer to a linear configuration, and that the core loss is low as a whole, and a rise in the high-frequency component can be reduced to a low level. A
substantially fixed permeability was obtained up to 200 kHz.
As described above, in accordance with the present invention, since the above-described arrangement is adopted, it is possible to improve the magnetic characteristics at a frequency higher than 10 kHz, and the space factor can be made as large as possible, thereby making contributions to making the magnetic core compact.
Claims (10)
1. A magnetic ribbon for winding or lamination into a magnetic core, the magnetic ribbon being formed of an amorphous metal and having coated on at least one surface thereof fine particles of 10 nm to 2 µm in size formed of a nonmagnetic metal oxide having electrically-insulating properties, the fine particles being attached to the surface in an amount of 10 -7 cm3 to 2 x 10 -4 cm3 per square centimeter of surface area so coarsely that an insulating layer of air is formed between adjacent magnetic ribbon layers when the magnetic ribbon is wound or laminated into the magnetic core.
2. A process for manufacturing a magnetic ribbon comprising the steps of:
a) coating a fine particles-containing dispersion on at least one surface of an amorphous metal ribbon, the particles being 10 nm to 2 µm in size formed of a nonmagnetic metal oxide having electrically-insulating properties, so as to attach the particles to the surface in an amount of 10 -7 cm3 to 2 x 10 -4 cm3 per square centimeter of surface area so coarsely that an insulating layer of air is formed between adjacent magnetic ribbon layers when the magnetic ribbon is wound or laminated into a magnetic core;
b) drying the coated ribbon, and c) annealing the dried coated ribbon for 0.5 to 5 hours at a temperature of 300 to 500°C in an inert gas atmosphere.
a) coating a fine particles-containing dispersion on at least one surface of an amorphous metal ribbon, the particles being 10 nm to 2 µm in size formed of a nonmagnetic metal oxide having electrically-insulating properties, so as to attach the particles to the surface in an amount of 10 -7 cm3 to 2 x 10 -4 cm3 per square centimeter of surface area so coarsely that an insulating layer of air is formed between adjacent magnetic ribbon layers when the magnetic ribbon is wound or laminated into a magnetic core;
b) drying the coated ribbon, and c) annealing the dried coated ribbon for 0.5 to 5 hours at a temperature of 300 to 500°C in an inert gas atmosphere.
3. A magnetic core comprising a lamination obtained by winding or laminating a magnetic ribbon, the magnetic ribbon being formed of an amorphous metal and having coated on at least one surface thereof fine particles of 10 nm to 2 µm in size formed of a nonmagnetic metal oxide having electrically-insulating properties, the fine particles being attached to the surface in an amount of 10-7cm3 to 2 x 10-4 cm3 per square centimeter of surface area, wherein a layer of the fine particles is formed between the adjacent magnetic ribbon layers and the particle are attached so coarsely that an insulating layer of air is also present between the adjacent magnetic ribbon layers.
4. A process for manufacturing a magnetic core comprising the steps of:
a) winding or laminating a magnetic ribbon, the magnetic ribbon being formed of an amorphous metal and having coated on at least one surface thereof fine particles of 10 nm to 2 µm in size formed of a nonmagnetic metal oxide having electrically-insulating properties, the fine particles being attached to the surface in an amount of 10-7 cm3 to 2 x 10-4 cm3 per square centimeter of surface area so coarsely that an insulating layer of air is formed between adjacent magnetic ribbon layers; and b) annealing the wound or laminated magnetic ribbon for 0.5 to 5 hours at a temperature of 300 to 500°C in an inert gas atmosphere.
a) winding or laminating a magnetic ribbon, the magnetic ribbon being formed of an amorphous metal and having coated on at least one surface thereof fine particles of 10 nm to 2 µm in size formed of a nonmagnetic metal oxide having electrically-insulating properties, the fine particles being attached to the surface in an amount of 10-7 cm3 to 2 x 10-4 cm3 per square centimeter of surface area so coarsely that an insulating layer of air is formed between adjacent magnetic ribbon layers; and b) annealing the wound or laminated magnetic ribbon for 0.5 to 5 hours at a temperature of 300 to 500°C in an inert gas atmosphere.
5. An electrical or electronic device comprising a magnetic core, the magnetic core comprising a lamination obtained by winding or laminating a magnetic ribbon, which is formed of an amorphous metal and has coated on at least one surface thereof fine particles of 10 nm to 2 µm in size formed of a nonmagnetic metal oxide having electrically-insulating properties, the fine particles being attached to the surface in an amount of 10 -7 cm3 to 2 x 10 -4 cm3 per square centimeter of surface area, wherein a layer of the fine particles is formed between the adjacent magnetic ribbon layers and the particles are attached so coarsely that an insulating layer of air is also present between the adjacent magnetic ribbon layers.
6. The magnetic ribbon according to claim 1, wherein the nonmagnetic metal oxide is antimony pentoxide and is attached to the surface in an amount of 3.8 x 10 -7 to 7.6 x -4 g/cm2.
7. The magnetic ribbon according to claim 6, wherein antimony pentoxide is attached to the surface in an amount of 1.1 x 10 -5 to 3.8 x 10 -5 g/cm2.
8. The magnetic core according to claim 3, wherein the nonmagnetic metal oxide is antimony pentoxide and is attached to the surface in an amount of 3.8 x 10 -7 to 7.6 x 10 -4 g/cm2.
9. The electrical or electronic device according to claim 5, wherein the nonmagnetic metal oxide is antimony pentoxide and is attached to the surface in an amount of 3.8 x
10-7 to 7.6 x 10-4 g/cm2.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63-88694(88694/1988) | 1988-04-11 | ||
| JP63088694A JP2716064B2 (en) | 1988-04-11 | 1988-04-11 | Magnetic ribbon and magnetic core |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1340795C true CA1340795C (en) | 1999-10-19 |
Family
ID=13949956
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000596211A Expired - Lifetime CA1340795C (en) | 1988-04-11 | 1989-04-10 | Magnetic ribbon and magnetic core |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0337716B1 (en) |
| JP (1) | JP2716064B2 (en) |
| KR (1) | KR920005490B1 (en) |
| AT (1) | ATE119309T1 (en) |
| CA (1) | CA1340795C (en) |
| DE (1) | DE68921363T2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5091253A (en) * | 1990-05-18 | 1992-02-25 | Allied-Signal Inc. | Magnetic cores utilizing metallic glass ribbons and mica paper interlaminar insulation |
| DE69109794T2 (en) * | 1990-10-03 | 1996-02-08 | Nippon Steel Corp | Process for the production of Permalloy cores. |
| JP2909349B2 (en) * | 1993-05-21 | 1999-06-23 | 日立金属株式会社 | Nanocrystalline soft magnetic alloy ribbon and magnetic core with insulating film formed thereon, pulse generator, laser device, accelerator |
| US20060017010A1 (en) * | 2004-07-22 | 2006-01-26 | Axcelis Technologies, Inc. | Magnet for scanning ion beams |
| JP5555725B2 (en) | 2012-01-13 | 2014-07-23 | 本田技研工業株式会社 | Electric load control device |
| US11715591B2 (en) | 2020-03-27 | 2023-08-01 | Proterial, Ltd. | Method for manufacturing a wound magnetic core |
| JP2023031770A (en) | 2021-08-25 | 2023-03-09 | Tdk株式会社 | Magnetic alloy ribbon, laminate and magnetic core |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS618903A (en) * | 1984-06-25 | 1986-01-16 | Kawasaki Steel Corp | Characteristics of amorphous alloy thin belt and improvement of dieing workability thereof |
| JPS61181114A (en) * | 1985-02-07 | 1986-08-13 | Toshiba Corp | Manufacture of rolled iron core |
| WO1986005314A1 (en) * | 1985-02-27 | 1986-09-12 | Kawasaki Steel Corporation | Laminate of thinamorphous alloy strip, core made of thin amorphous alloy strip, and process for their production |
| JPS61198611A (en) * | 1985-02-27 | 1986-09-03 | Kawasaki Steel Corp | Manufacture of transformer with amorphous alloy thin band core |
| JPS6210278A (en) * | 1985-07-09 | 1987-01-19 | Kawasaki Steel Corp | Thin amorphous alloy strip having excellent paramagnetic permeability |
| JPS6261308A (en) * | 1985-09-11 | 1987-03-18 | Toshiba Corp | Heat treatment of amorphous wound core |
| JPS6265403A (en) * | 1985-09-18 | 1987-03-24 | Kawasaki Steel Corp | Improving magnetic characteristics of amorphous alloy thin band |
| JPS62188209A (en) * | 1986-02-13 | 1987-08-17 | Tdk Corp | Manufacture of wound core |
-
1988
- 1988-04-11 JP JP63088694A patent/JP2716064B2/en not_active Expired - Fee Related
-
1989
- 1989-04-10 CA CA000596211A patent/CA1340795C/en not_active Expired - Lifetime
- 1989-04-11 KR KR1019890004745A patent/KR920005490B1/en not_active IP Right Cessation
- 1989-04-11 AT AT89303542T patent/ATE119309T1/en not_active IP Right Cessation
- 1989-04-11 DE DE68921363T patent/DE68921363T2/en not_active Expired - Fee Related
- 1989-04-11 EP EP89303542A patent/EP0337716B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0337716B1 (en) | 1995-03-01 |
| DE68921363T2 (en) | 1995-07-13 |
| JP2716064B2 (en) | 1998-02-18 |
| KR920005490B1 (en) | 1992-07-06 |
| EP0337716A2 (en) | 1989-10-18 |
| KR890016591A (en) | 1989-11-29 |
| JPH01259510A (en) | 1989-10-17 |
| DE68921363D1 (en) | 1995-04-06 |
| ATE119309T1 (en) | 1995-03-15 |
| EP0337716A3 (en) | 1990-09-19 |
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