JPH06333721A - Magnetic ferrite, laminated type inductor part, composite laminated part and magnetic core - Google Patents

Abstract

PURPOSE:To realize magnetic ferrite capable of being manufactured in a comparatively short time as electromagnetic characteristics are left as they are at least maintained by using copper hydroxide as the starting raw material of a Cu component. CONSTITUTION:A laminated type inductor 1 has a chip body 10 constituted by alternately laminating and unifying magnetic substance bodies 2 and conductor layers 3. Ni-Cu-Zn magnetic ferrite is used as the quality of material of the magnetic substance layers 2 of the laminated type inductor 1. A baking material at a low temperature is employed as the Ni-Cu-Zn magnetic ferrite, and the composition of the baking material consists of 45-50mol% Fe2O3, 4-50mol% NiO, 3-30mol% CuO and 0.5-35mol% ZnO. Copper hydroxide is used as a Cu component in a starting raw material at that time. Accordingly, raw material powder can be compounded and mixed in a short time, and magnetic ferrite having excellent electromagnetic characteristics can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic ferrite used as various magnetic materials, an inductor using the magnetic ferrite as a magnetic material, a composite laminated component such as an LC composite component, and a magnetic core.

[0002]

2. Description of the Related Art Various ferrites are used as various magnetic cores and composite laminated parts because of their excellent magnetic properties.

A laminated LC composite component integrally includes a capacitor chip body formed by laminating a ceramic dielectric layer and an internal electrode layer, and an inductor chip body formed by laminating a ferrite magnetic layer and an internal conductor. It was formed in a proper manner.

Such a composite laminated component is widely used in various electronic devices because of its small volume, high robustness and high reliability.

These parts, for example, LC composite parts, are usually formed by laminating the internal conductor paste, the magnetic layer paste, the dielectric layer paste and the internal electrode layer paste by a thick film technique and then firing them. It is manufactured by printing or transferring an external electrode paste on the surface of the obtained sintered body and then firing it. In this case, the magnetic material used for the magnetic layer is Ni because it can be fired at a low temperature.
-Cu-Zn type ferrite is generally used.

Such Ni-Cu-Zn type ferrite is manufactured as follows. As the starting material, NiO, CuO, ZnO, Fe ₂ O ₃ or the like is usually used,
An appropriate amount of them is weighed and wet mixed by a ball mill or the like. The thus wet-mixed product is usually dried by a spray dryer, then calcined, and the calcined body is wet-ground by a ball mill to obtain ferrite powder.

[0007]

The Ni-Cu-Zn type ferrite is produced in a manner generally described above. However, when various electronic components are produced by using the ferrite powder produced as described above, the transparency In some cases, problems such as deterioration of magnetism and decrease of sintered density may occur.

The inventors of the present invention have made a study on such a phenomenon. As a result, the electrical characteristics of ferrite are remarkably influenced by the degree of mixing of the raw materials, and particularly in the Ni-Cu-Zn type ferrite, the dispersion of CuO. It was found that it was difficult and when the mixing time was short, CuO was not sufficiently dispersed and segregated in ferrite, and the segregated CuO became a magnetic gap, causing the above problems. .

Therefore, Ni-Cu-Z having good characteristics is obtained.
In order to manufacture the n-type ferrite, it is sufficient to take a sufficient mixing time, but of course, this causes a problem that the manufacturing time becomes long and the manufacturing cost becomes high.

Therefore, an object of the present invention is to provide a magnetic ferrite which can be manufactured in a relatively short time while at least maintaining the electromagnetic characteristics.

[0011]

The above objects are achieved by the present invention described in (1) to (6) below. (1) A magnetic ferrite containing NiO, CuO, ZnO and Fe ₂ O ₃ , wherein copper hydroxide is used as a starting material for a Cu component. (2) the composition of the ferrite is Fe ₂ O _3: 45~50mo
1%, NiO: 4 to 50 mol%, CuO: 3 to 30 m
ol% and ZnO: 0.5 to 35 mol% of the magnetic ferrite according to the above (1). (3) An inductor component having an inductor portion configured by laminating a ferrite magnetic layer and an internal conductor layer,
A multilayer chip inductor component, wherein the ferrite magnetic layer is composed of the magnetic ferrite of (1) or (2) above. (4) A composite laminated component having at least an inductor portion formed by laminating a ferrite magnetic layer and an internal conductor layer, wherein the ferrite magnetic layer is formed of the magnetic ferrite of (1) or (2) above. Composite laminated parts characterized by being (5) A composite laminated component in which a circuit is composed of a ferrite magnetic layer and a dielectric layer, wherein the ferrite magnetic layer is composed of the magnetic ferrite of (1) or (2) above. parts. (6) A magnetic core composed of a magnetic ferrite sintered body obtained by firing the magnetic ferrite of (1) or (2) above.

[0012]

In the magnetic ferrite of the present invention, since copper hydroxide is used as the Cu component of the starting material, the dispersibility is improved by mixing for a short time, and CuO does not precipitate in the ferrite. Therefore, when an electronic component such as an inductor is manufactured using the magnetic ferrite of the present invention, the permeability and the sintered density do not deteriorate even if the mixing time of the raw materials is shortened.

[0013]

Specific Structure The specific structure of the present invention will be described in detail below.

<Composition of Ferrite> As the magnetic ferrite of the present invention, Ni—Cu—Zn magnetic ferrite is used. There is no particular restriction on the Ni-Cu-Zn system ferrite magnetic ferrite, may be selected having various compositions depending on the _{purpose, Fe 2 O 3: 45~50mol%} , especially 47.
5-49.5 mol%, NiO: 4-50 mol%, especially 5-45 mol%, CuO: 3-30 mol%, especially 4.5-15.5 mol% and ZnO: 0.5-35.
It is preferable that the content is mol%, particularly 1 to 31 mol%.

Besides, Co, Mn, etc. may be contained in an amount of about 5 wt% or less of the whole, and Ca, Si, Bi,
V, Pb, etc. may be contained in an amount of about 1 wt% or less.

A feature of the present invention is that copper hydroxide is used as the Cu component of the starting material for the magnetic ferrite. Here, copper hydroxide is copper (I) Cu
Both (OH) and copper (II) hydroxide Cu (OH) ₂ are included.

<Multilayer Inductor> FIGS. 1 and 2 show a preferred example of the multilayer inductor of the present invention, that is, the multilayer inductor.

The laminated inductor 1 has a chip body 10 formed by alternately laminating magnetic layers 2 and conductor layers 3.

The conductor layer 3 is formed in a pattern, and adjacent conductor layers 3 are electrically connected to each other as shown in FIG. 2, thereby forming a coil.

Further, on the surface of the chip body 10, an external electrode 5 which is electrically connected to the conductor layer 3 is provided.

The outer shape and size of the chip body 10 are not particularly limited and may be appropriately selected depending on the application. Usually, the outer shape is a substantially rectangular parallelepiped shape, and the size is (1.0 to 5.
6) mm × (0.5 to 5.0) × (0.6 to 1.9) mm.

As the material of the magnetic layer 2 of the laminated inductor 1, the above Ni-Cu-Zn magnetic ferrite is used. The Ni-Cu-Zn magnetic ferrite is
It is a low temperature firing material, and when such a magnetic layer is used,
The multilayer inductor of the present invention does not generate a liquid phase during firing,
Moreover, it becomes more excellent in terms of electric resistance.

Such a ferrite-based magnetic layer 2
Can be formed by simultaneous firing with the conductor layer paste described below at a firing temperature of 800 to 950 ° C., particularly 850 to 900 ° C.

The thickness of the magnetic layer 2 after firing is not particularly limited, but usually the base thickness is about 250 to 500 μm, and the magnetic layer thickness between the conductor layers 3 and 3 is about 10 to 100 μm. To do.

As the material for the conductor layer 3, any conventionally known material for the conductor layer can be used.

For example, Ag, Cu, Pd or alloys thereof may be used. Among them, Ag or Ag alloy,
Ag is particularly preferable.

As the Ag alloy, an Ag-Pd alloy containing 95% by weight or more of Ag is suitable.

The conductor layer 3 is formed by applying a conductor layer paste and firing it as described later.

At this time, usually, voids are often formed inside the conductor layer 3 due to binder removal or the like.

The conductor layer 3 is, as shown in FIG.
The magnetic layer 2 is usually arranged in a spiral shape, and both ends thereof are connected to the pair of external electrodes 5 and 5, respectively.

In such a case, the winding pattern of the conductor layer 3, that is, the shape of the closed magnetic circuit can be various patterns, and the number of turns, the thickness, the pitch and the like may be appropriately selected according to the application. .

The thickness of the conductor layer 3 is usually 5 to 30.
μm, winding pitch is usually 40-100 μm,
The number of turns may normally be about 1.5 to 50.5 turns.

Regarding the material of the external electrodes 5 and 5,
There is no particular limitation, and various conductive materials such as Ag, Ni,
A printed film, a plated film, a vapor deposition film, an ion plating film, a sputtered film, or a laminated film of these, such as Cu or the like or an alloy thereof such as Ag-Pd, can be used.

The thickness of the external electrodes 5 and 5 is arbitrary and may be appropriately determined according to the purpose and application, but is usually 5 to 30 μm.
It is a degree.

<Method of Manufacturing Multilayer Inductor> Next, a method of manufacturing the multilayer inductor of the present invention will be described.

First, the magnetic layer paste, the conductor layer paste, and the external electrode paste are manufactured.

<Magnetic Layer Paste> The magnetic layer paste may be manufactured by a usual method.

For example, in order to produce a ferrite paste, a predetermined amount of NiO, ZnO, Cu (OH) ₂ , Fe ₂
A ferrite raw material powder such as O _{3 is} wet mixed by a ball mill or the like. The average particle diameter of each raw material powder used is usually 0.1
It is about 10 μm.

The thus wet-mixed product is usually dried by a spray dryer or the like, and then calcined. Usually, this is wet pulverized by a ball mill etc. until the average particle size becomes about 0.01 to 0.1 μm, and dried by a spray dryer or the like.

The obtained mixed ferrite powder, a binder such as ethyl cellulose and acrylic resin, and a solvent such as terpineol and butyl carbitol are mixed and kneaded with, for example, a three-roll mill to form a paste.

In this case, the paste can contain various glasses and oxides.

In addition to ferrite powder, various magnetic particles can be used.

<Conductor Layer Paste> The conductor layer paste usually contains conductive particles, a binder, and a solvent.

The material of the conductive particles is not particularly limited as long as it is one that has been conventionally used for a conductor layer paste, and a material that becomes a metal after firing a metal or a metal oxide may be used.

In this case, the metal components are Ag and C.
A simple metal containing at least one of u and Pd, or an alloy thereof is preferable.

Particularly preferred are Ag, Ag alloys and oxides thereof.

The shape of the conductive particles is not particularly limited, but a substantially spherical shape is preferable. The average particle diameter D of the conductive particles is 0.1 to 1 μm, particularly 0.1 to 0.4 μm.
It is preferably m.

If it is less than the above range, it is difficult to form a paste and it is not suitable for printing.

If it exceeds the above range, a high density conductor layer cannot be formed.

In this case, in the present invention, it is preferable to use conductive particles having a sharp particle size distribution.

Specifically, when the average particle size of the conductive particles is D, it is preferable that particles having a particle size of D / 2 to 2D are present in an amount of 30% by weight or more, and particularly 40% by weight or more. .

However, since it is difficult to make it too large, it is preferable to set it to 30 to 60% by weight, particularly 40 to 60% by weight.

If it is less than the above range, a high-density conductor layer cannot be formed.

The particle size of the conductive particles may be calculated by observing with an SEM and converting the projected area of the particles into a circle.

<Binder> As the binder, any known binder such as ethyl cellulose, acrylic resin, butyral resin can be used.

The binder content is usually about 1 to 5% by weight.

Any known solvent such as terpineol, butyl carbitol, kerosene can be used as the solvent.

The solvent content is usually about 10 to 50% by weight. In addition, if necessary, within a total amount of about 10% by weight or less, a dispersant such as sorbitan fatty acid ester and glycerin fatty acid ester, a plasticizer such as dioctyl phthalate, dibutyl phthalate, and butyl phthalyl glycolate butyl, and delamination prevention For the purpose of suppressing sintering, various ceramic powders such as a dielectric material, a magnetic material, and an insulating material may be added.

The above compositions are mixed and kneaded with, for example, a three-roll mill to form a paste.

In this case, in the manufacturing method of the present invention, the conductive particles are kneaded so as to be dispersed in the paste without excess or deficiency.

Specifically, the conductive layer paste after kneading is applied onto a base material such as polyethylene terephthalate,
When the uppermost surface of the coating film is observed with a SEM image of 2000 to 10000 times, the area ratio of the region where the conductive particles do not exist on the outermost surface of the coating film is 20 to 60%, preferably 30 to 5
Kneading is carried out until it reaches 0%, particularly preferably 35 to 45%.

In this case, the outermost surface of the coating film is a region of about 1 to 5 times the average particle diameter D of the conductive particles.

If it is less than the above range or exceeds the above range, the sectional area ratio occupied by the conductor layer 3 in the gap 6 is 8 or less.
More than 5%, the contact ratio between the magnetic layer 2 and the conductor layer 3 exceeds 50%, and the porosity of the conductor layer 3 is 50%.
Over.

In order to obtain the conductor layer paste having such desired dispersibility, for example, the roll gap of the three rolls, the viscosity, the kneading time, etc. may be appropriately adjusted.

As the external electrode paste, an ordinary paste containing the above-mentioned conductor material powder may be used.

The magnetic layer paste and the conductor layer paste are laminated by a printing method, a transfer method, a green sheet method or the like.

Then, after cutting into a predetermined laminate size,
Perform firing.

The firing conditions and firing atmosphere may be appropriately determined depending on the material and the like, but are usually as follows.

Firing temperature: about 850 to 950 ° C. Firing time: about 0.5 to 5 hours

When Cu, Ni or the like is used for the conductor layer, a non-oxidizing atmosphere is used. In addition, when Ag, Pd or the like is used, the atmosphere may be used.

<Composite Laminated Parts> FIG. 3 shows a laminated ceramic LC composite part which is a preferred embodiment of the present invention.

The LC composite component 20 shown in FIG. 3 has a capacitor chip body CT formed by laminating a ceramic dielectric layer 21 and an internal electrode layer 25, and a ceramic magnetic layer 31.
An inductor chip body IT formed by stacking an internal conductor 35 and an internal conductor 35 is integrated, and has an external electrode 51 on the surface. Since the inductor chip body IT itself may be the same as the chip body 10 of the multilayer inductor 1,
The description is omitted here.

<Capacitor Chip Body> There are no particular restrictions on the ceramic dielectric layer 21 of the capacitor chip body CT, and various dielectric materials may be used. However, since the firing temperature is low, a titanium oxide-based dielectric material is used. Is preferred. In addition, a titanic acid-based composite oxide, a zirconic acid-based composite oxide, or a mixture thereof can also be used. Further, glass such as borosilicate glass may be contained in order to lower the firing temperature.

Specifically, as the titanium oxide type, NiO, CuO, Mn ₃ O ₄ , Al ₂ O ₃ and Mg may be used, if necessary.
O, SiO _{2 and the} like, particularly TiO _{2 and the} like containing CuO, and BaTiO ₃ and SrTiO ₃ as titanic acid-based composite oxides.
₃ , CaTiO ₃ , MgTiO ₃ and mixtures thereof include BaZrO ₃ as a zirconate complex oxide,
Examples thereof include SrZrO ₃ , CaZrO ₃ , MgZrO ₃ and mixtures thereof.

<Internal Electrode Layer> In the present invention, the conductive material forming the internal electrode layer 25 is not particularly limited, and Ag, P
It may be selected from t, Pd, Au, Cu, Ni, alloys containing at least one of these, such as Ag-Pd alloy, and Ag alloys such as Ag and Ag-Pd alloy are particularly preferable. .

<Structure> The capacitor chip body CT of the LC composite component 1 may have a conventionally known structure, and its outer shape is usually a substantially rectangular parallelepiped shape. Then, as shown in FIG. 1, one end of the internal electrode layer 25 is connected to the external electrode 51.

There are no particular restrictions on the dimensions of each part of the capacitor chip body CT, which may be appropriately selected according to the application.

The number of laminated dielectric layers 21 may be determined according to the purpose, but is usually about 1 to 100. Also,
The thickness of each dielectric layer 21 is usually 20 to 150.
The thickness of each internal electrode layer 25 is usually about 5 to 30 μm.

<Conductive Material of External Electrode> The conductive material of the external electrode 51 of the LC composite component 1 of the present invention is not particularly limited, and examples thereof include Ag, Pt, Pd, Au, Cu, Ni and A.
It may be selected from alloys containing at least one of these, such as g-Pd alloy, and Ag alloys such as Ag and Ag-Pd alloy are particularly preferable. The shape and size of the external electrode 51 are not particularly limited and may be appropriately determined depending on the purpose and application, but the thickness is usually 100 to 2500 μm.
It is a degree.

<Structure of LC composite part> The size of the LC composite part 1 of the present invention is not particularly limited and may be appropriately selected according to the purpose and application, but is usually (2.0 to 10.0 mm).
It is about x (1.2 to 15.0 mm) x (1.2 to 5.0 mm).

<Magnetic Core> By using the magnetic ferrite of the present invention as a magnetic core material, a magnetic core having excellent characteristics can be obtained in a short manufacturing time.

[0082]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention.

In this specification, since the effect can be specified by the chip inductor, the embodiment of the composite laminated component will be omitted.

The following pastes were prepared.

(Paste for magnetic layer) Fe _{2 with the} final composition
O ₃ : 49 mol%, NiO: 8 mol%, Cu (O
The starting materials were mixed so that H) ₂ : 13 mol% and ZnO: 30 mol%. These are wet-mixed for 5 hours using a ball mill, and then the wet mixture is dried by a spray dryer and calcined at 700 ° C., and the granules are wet-ground by a ball mill and then dried by a spray dryer. , Final average particle size 0.1-0.3μ
m was used as the Ni-Cu-Zn ferrite raw material powder. As described above, the Ni-Cu-Zn ferrite raw material powder according to the example of the present invention was obtained.

On the other hand, instead of Cu (OH) ₂ , CuO
Wet mixing for 16 hours and 5 hours at different times,
Others are the same as those in the above-described embodiment, and N of Comparative Examples 1 and 2
A raw material powder of i-Cu-Zn ferrite was obtained. Also, Cu
Cu ₂ O was used in place of (OH) ₂ and wet-mixed for 5 hours.
-Cu-Zn ferrite raw material powder was obtained.

Next, to 100 parts by weight of these raw material powders, 3.84 parts by weight of ethyl cellulose and 78 parts by weight of terpineol were added and kneaded with a three-roll to form a paste.

(Internal conductor paste) Average particle size 0.8 μ
2.5 parts by weight of ethyl cellulose to 100 parts by weight of Ag of m
Parts by weight and 40 parts by weight of terpineol were added, and the mixture was kneaded with a three-roll to form a paste.

The magnetic layer paste and the internal conductor paste thus produced were printed and laminated to produce a multilayer chip inductor.

In this case, the firing temperature was 890 ° C., the firing time was 2 hours, and the firing atmosphere was the atmosphere.

The dimensions of the obtained laminated chip inductor were 3.2 mm × 1.6 mm × 1.1 mm and the number of turns was 9.5 turns.

A toroidal core was manufactured under the same firing conditions using the above ferrite raw material powder for the test. The toroidal core had an outer diameter of 11.1 mm, an inner diameter of 5.1 mm, a thickness of 2.4 mm, a winding number of 20 turns, and a wire diameter of 0.35 mm.

With respect to the above laminated chip inductor, L (inductance) and Q under the condition of measurement frequency of 400 kHz, and shrinkage rate after firing, density g / cm ³ , and measurement frequency of 40 were measured for the toroidal core.
Μ, Q, and the like under the condition of 0 kHz were obtained. The obtained results are shown in Tables 1 and 2.

[0094]

[Table 1]

[0095]

[Table 2]

As can be seen from the results shown in Tables 1 and 2, by changing the raw material for the blending from copper oxide to copper hydroxide, even if the blending and mixing time is short (5 hours),
Electromagnetic properties equivalent to those for 6 hours) were obtained. Further, as can be seen from Table 2, the sinterability is improved and the sintering density is also improved. The reason for this is that by using copper hydroxide instead of copper oxide, each raw material powder is uniformly dispersed even during a short time (5 hours) of mixing and mixing, and segregation of CuO, which was a cause of magnetic deterioration, is eliminated. It is considered that a uniform ferrite structure was obtained.

[0097]

As is clear from the above, according to the present invention, the raw material powders can be blended and mixed in a short time, and a magnetic ferrite having excellent electromagnetic characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a laminated inductor of the present invention.

FIG. 2 is a partially broken plan view of the multilayer inductor.

FIG. 3 is a perspective view in which a part of the composite LC laminated component of the present invention is cut away.

[Explanation of symbols]

 1 Multilayer Inductor 2 Magnetic Layer 3 Conductor Layer 5 External Electrode 10 Chip Body 20 Composite LC Multilayer Component CT Capacitor Chip Body IT Inductor Chip Body 21 Ceramic Dielectric Layer 25 Internal Electrode 31 Ceramics Magnetic Layer 35 Internal Conductor 51 External Electrode

Claims (6)

[Claims] 1. NiO, CuO, ZnO and Fe ₂ O
_{In the} magnetic ferrite containing ₃ , copper hydroxide is used as a starting material for the Cu component. 2. The composition of ferrite is Fe ₂ O ₃ : 45-.
50 mol%, NiO: 4 to 50 mol%, CuO: 3
The magnetic ferrite according to claim 1, which is -30 mol% and ZnO: 0.5-35 mol%. 3. An inductor component having an inductor portion formed by laminating a ferrite magnetic layer and an internal conductor layer, wherein the ferrite magnetic layer is formed of the magnetic ferrite according to claim 1. Characteristic multilayer chip inductor parts. 4. A composite laminated component having at least an inductor portion formed by laminating a ferrite magnetic layer and an internal conductor layer, wherein the ferrite magnetic layer is formed of the magnetic ferrite according to claim 1 or 2. A composite laminated component characterized in that 5. A composite laminated component in which a circuit is composed of a ferrite magnetic layer and a dielectric layer, wherein the ferrite magnetic layer is composed of the magnetic ferrite of claim 1 or 2. . 6. A magnetic core composed of a magnetic ferrite sintered body obtained by firing the magnetic ferrite according to claim 1.