JPH09148118A - Laminated compressed powder magnetic core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the cost up while enabling the excellent characteristics to be exhibited in a simple structure by a method wherein a magnetic body layer is composed of a compound body made of alloy particles mainly comprising Fe, Si, Al as well as borosilicate base glass or a heat resistant adhesive agent containing silica. SOLUTION: Alloy particles mainly comprising Fe, Si, and Al are produced by water atomizing process. Next, this alloy particles are mixed with about 5wt.% of borosilicate glass to the alloy particle weight to be made into the mixed particles for magnetic body layer. Next, this mixed particles and polybutyral (a binder) are blended with a solvent to be kneaded for producing a paste 11 for magnetic body layer. Next, this paste 1 for magnetic body layer is laminated by printing process. Finally, a conductor is print laminated so as to form a laminated layer winding using another paste 2 for conductor layer and the paste 1 for magnetic body layer on the laminated layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated dust core used in various electronic devices.

[0002]

2. Description of the Related Art A powder magnetic core made of a ferrite magnetic core or an alloy powder is used for suppressing electromagnetic noise or as a choke coil. With the recent trend toward miniaturization of electronic devices, the frequency with which these magnetic core components are used for surface mounting is increasing. In such a surface-mount type magnetic core, at present, after forming a magnetic core by a method such as combining a wound pot core with a lid or combining a wound drum core with a ring core, the external electrodes are directly formed on the core body. It is manufactured by

[0003]

Since the magnetic core manufactured by such a method forms a closed magnetic circuit, it has a high inductance and an effect of reducing the influence of leakage magnetic flux to the outside. It is extremely difficult to reduce the manufacturing cost because a step of combining windings and cores is required after manufacturing individual cores.

An object of the present invention is to solve the above problems,
An object is to provide a laminated dust core having a simple structure and high characteristics while avoiding an increase in cost.

[0005]

According to the present invention, a magnetic layer and a conductive layer made of conductive powder are laminated to form a laminated winding of a conductor, and the laminated winding is heat-treated. In the core, the magnetic layer is made of a composite of an alloy powder containing Fe, Si, and Al as main components and a heat-resistant adhesive containing borosilicate glass or silica. The core is obtained.

Further, according to the present invention, Fe, Si, Al
A magnetic material layer sheet consisting of a composite of an alloy powder containing as a main component and a borosilicate glass composite, or a heat-resistant adhesive containing silica, and a metal foil conductor are alternately laminated and adhered to each other, and a conductor is laminated. A laminated dust core characterized in that the winding is formed is obtained.

[0007]

In the present invention, a magnetic layer made of a composite of an alloy powder containing Fe, Si and Al as main components and a borosilicate glass and a conductive layer made of conductive powder are laminated by a printing method. By forming a laminated winding of a conductor and heat-treating the laminated winding, the alloy powder particles are fixed by a heat resistant adhesive containing a glass component or silica to form a laminated dust core.

In the laminated dust core of the present invention, since the conductor layer and the magnetic layer made of metal powder are in direct contact with each other, it is desirable that the magnetic layer has high resistivity and withstand voltage. .

By using Fe, Si, and Al as main components as an alloy composition, an oxide film of Si or Al is produced on the surface of the powder particles, and a magnetic layer having high resistivity and withstand voltage is formed.

According to the second aspect of the present invention, by using the metal foil as the conductor layer, it is possible to obtain a laminated dust core having a low electric resistance without sintering the conductor layer. It becomes possible, and heat treatment at a relatively low temperature becomes possible.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A laminated dust core according to an embodiment of the present invention will be described below with reference to the drawings.

Example 1 Alloy powders having the compositions shown in Table 1 and having an average particle size of 10 μm were produced by a water atomizing method. Borosilicate glass having an average particle size of 10 μm was mixed with these alloy powders in an amount of 5 wt% with respect to the weight of the alloy powder to obtain a mixed powder for a magnetic layer. This mixed powder and polybutyral (binder) were mixed with a solvent in the ratio shown in Table 2, and the mixture was kneaded with a three-roll mill to prepare each magnetic paste.

[0013]

[Table 1]

[Table 2] Next, as a conductor powder, Ag having an average particle diameter of 0.5 μm was used.
A powder was prepared. This powder was mixed with polyvinyl butyral (binder) and a solvent in the proportions shown in Table 3, and the mixture was kneaded with a three-roll mill to prepare a conductor layer paste.

[0014]

[Table 3] In the examples, the respective pastes were prepared with the compounding ratios shown in Tables 2 and 3 above, but other components and compounding ratios may be used as long as a printable paste can be obtained.

Next, the various magnetic layer pastes thus produced were laminated by printing to a predetermined thickness (about 0.5 mm). Printing and lamination were performed thereon by using the conductor layer paste and the magnetic layer paste so as to form a laminated winding of the conductor of 10 turns. At this time, the laminated thickness of one layer is about 50 μm for the magnetic layer and about 20 μm for the conductor layer.
I went in. The magnetic paste was laminated thereon by a printing method so as to have a predetermined thickness (about 0.5 mm).

In this embodiment, the number of laminated windings of the conductor is 10
Although the number of turns is not limited to this, the number of turns may be other than this, and the winding may be adjusted to obtain the required characteristics.

The various laminated bodies thus prepared were each cut into a predetermined size (9 mm × 7 mm). FIG. 1 shows the structure of the laminated body. FIG. 1A is a view from the stacking plane direction, and FIG. 1B is a sectional view. In the figure, 1 is a magnetic layer portion, 2 is a conductor layer portion, and 3 is an external electrode.

Each of the laminated and cut laminates was debindered in the air at 400 ° C. and then heat-treated in the air at 750 ° C. Next, the heat-treated laminated body was coated with a conductive paste on the surface of the conductor, where the leads of the laminated winding were exposed, and baked at about 300 ° C. to form external electrodes.

The inductance of each laminated magnetic core manufactured as described above was measured at a frequency of 100 kHz. The results are shown in Table 4.

[0020]

[Table 4] As is clear from Table 4, the laminated dust core of this example is
Has sufficient inductance characteristics for practical use.

Example 2 In the magnetic paste prepared in Example 1, the composition of the alloy powder was bal. Fe-10.0wt% Si-50wt
% Al was used to form a magnetic sheet by laminating the paste to a predetermined thickness (about 0.5 mm) by a printing method.
Next, an Ag foil having a thickness of 30 μm was punched into a predetermined shape so as to form a laminated winding to obtain a metal foil for a conductor.
As the metal foil for the conductor, in addition to Ag, Cu, A
1, Pd, Ag-Pd, etc. can be used, and the thickness of the foil may be adjusted according to the structure of the element.

Next, the magnetic metal sheet and the magnetic layer paste were laminated on the magnetic sheet so as to form a laminated winding of the conductor of 10 turns. At this time, the layer thickness of the magnetic layer was about 50 μm. On top of that, a magnetic paste was laminated to a predetermined thickness (about 0.5 mm) by a printing method.

In the embodiment, the laminated winding of the conductor is 10 turns, but the number of turns may be other than this, and the winding may be adjusted so as to obtain the required characteristics.

The above-prepared laminated body was formed into a predetermined size (9
mm × 7 mm).

The laminated and cut laminates were debindered in the air at 400 ° C. and then heat-treated in the air at 750 ° C. Next, in this heat-treated laminated body, a conductive paste is applied to the surface of the conductor where the leads of the laminated winding are exposed,
Baking was performed at about 300 ° C. to form external electrodes.

Frequency 1 of the laminated magnetic core manufactured as described above
The inductance at 00 kHz was measured. Also,
The DC resistance between the external electrode terminals was measured. The results are shown in Table 5.
Shown in For comparison, the measured values of the laminated dust core prepared in Example 1 and having the magnetic layer of the same composition are shown.

[0027]

[Table 5] As is clear from Table 5, the laminated dust core of this example also
Has sufficient inductance characteristics for practical use.

From the results of Examples 1 and 2, according to the present invention,
It has been clarified that a laminated dust core having sufficiently practical characteristics can be obtained.

In the examples of the present invention, only the results for the compositions shown in Table 1 are described, but the present invention is not limited to this, and Fe, Si, Al as the main component system are used. A similar result can be obtained with the alloy composition described above, and it can be easily guessed by those skilled in the art that the range is within the scope of the present invention.

[0030]

As described above, according to the present invention, a magnetic layer made of a composite of an alloy powder containing Fe, Si and Al as main components and a borosilicate glass and a conductive layer made of conductive powder are provided. By laminating by a printing method to form a laminated winding of a conductor and heat-treating the laminated winding, alloy powder particles are fixed by a heat resistant adhesive containing a glass component or silica to form a laminated dust core.

Therefore, after producing the individual cores, the windings,
Since the step of combining the cores is unnecessary, the manufacturing cost can be reduced.

Therefore, it is possible to provide a laminated dust core having a simple structure and high characteristics while avoiding an increase in cost.

According to the second aspect of the present invention, by using the metal foil as the conductor layer, it is possible to obtain a laminated dust core having a low electric resistance without sintering the conductor layer. It becomes possible, and heat treatment at a relatively low temperature becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a laminated inductor according to an embodiment of the present invention.

[Explanation of symbols]

 1 magnetic material layer 2 conductor layer 3 external electrode

Claims (2)

[Claims] 1. A laminated magnetic core in which a magnetic substance layer and a conductor layer made of a conductive powder are laminated to form a laminated winding of a conductor, and the laminated winding is heat-treated, wherein the magnetic layer is Fe. , S
A laminated dust core comprising a composite of an alloy powder containing i and Al as a main component and a heat-resistant adhesive containing borosilicate glass or silica. 2. The laminated dust core according to claim 1, wherein a magnetic layer sheet made of a composite of the alloy powder and a heat-resistant adhesive containing borosilicate glass or silica, and a metal foil conductor. A laminated powder magnetic core, wherein laminated windings of a conductor are formed by alternately laminating and adhering.