JPH0536514A - Composite magnetic material - Google Patents

Abstract

PURPOSE:To provide a composite magnetic material with high saturation flux density, high electric resistance and high magnetic permeability which is excellent in high frequency characteristics. CONSTITUTION:An operation wherein nitrogen atomized alloy powder (with average particle diameter of 30mumphi) having a composition of Fe-Si-Al is soaked into aqueous solution of NiCl2 and ZnCl2 and oxidized in the air is repeated to cause ferrite-producing reaction to form a soft magnetic Ni-Zn thin ferrite film. Further Al sputtering is performed in a nitrogen atmosphere to form an insulation film mainly containing AlN on a surface of the powder. B2O3 is added by 0.1vol.%, pressure-molding and hot-pressing is performed to obtain a composite sintered body with high density (relative density of 98 to 99%).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite magnetic material which can be effectively used for electronic parts, electronic devices and the like which utilize magnetic circuits such as magnetic recording heads such as transformers.

[0002]

2. Description of the Related Art Conventionally, as a magnetic material used for electronic parts and electronic equipment, ferrite having high electric resistance has been used when high magnetic permeability is required in a high frequency region. However, the saturation magnetic flux density of ferrite is about 1/2 that of metal magnetic materials.
I got only a small one.

On the other hand, a magnetic material having a high saturation magnetic flux density and a high electric resistance possessed by a metal magnetic material has been developed, which is a composite material of a magnetic metal and a non-magnetic insulating material, but its magnetic permeability has a sufficient value. Not obtained. Attempts have also been made to improve the overall magnetic permeability by using a magnetic material with high electrical resistance instead of a non-magnetic insulating material, but in this case it is difficult to obtain sufficient electrical resistance and Current loss and other losses increase, and a magnetic material having good high frequency characteristics has not been obtained.

[0004]

In the conventional magnetic metal and non-magnetic insulating material, in order to obtain high electric resistance, the magnetic metal material portion has a high electric resistance substance having a thickness of several hundred nm to several μm or more. The film was covered with a film of No. 3, and the magnetic metal part had a structure like a discontinuous body. Therefore, the magnetic flux passing through the inside of the composite is cut off at various places by the non-magnetic insulator, so that the magnetic permeability of the composite is significantly reduced. On the other hand, the composite material of magnetic metal and high electric resistance magnetic material has a problem that sufficient electric resistance cannot be obtained.

In order to solve the above problems, it is an object of the present invention to provide a composite magnetic material having excellent characteristics of high saturation magnetic flux density, high electric resistance and high magnetic permeability.

[0006]

In order to solve the above-mentioned problems, the composite magnetic material of the first invention of the present invention comprises a matrix particle (first substance) made of a magnetic metal, a high electric resistance and a high electric resistance. It is composed of a fine particle size composite consisting of at least three kinds of substances of magnetic permeability (second substance) and high electric resistance different from the second substance (third substance). The surface is covered with at least the second substance, and the third substance has at least three layers of structure substantially covering the second substance, and between the matrix particles, the second substance and It is a composite magnetic material that is substantially isolated by the third substance.

In the above structure, it is preferable that the first substance is an Fe-based metal magnetic material and the second substance is ferrite. The composite magnetic material according to the second aspect of the present invention is a high-electricity material different from the matrix particles (first substance) made of a magnetic metal, the high electric resistance substance (third substance), and the third substance. It consists of a fine particle size composite consisting of at least three kinds of substances of resistance and high magnetic permeability (second substance), and the surface of the matrix phase particles is almost covered with the third substance. Two
Is a composite magnetic material in which the substance has a structure of at least three layers that substantially covers the third substance, and the matrix particles are substantially separated from each other by the third substance and the second substance. .

In the above structure, it is preferable that the first substance is an Fe-based metal magnetic substance and the third substance is ferrite.

[0009]

The composite magnetic material of the first invention of the present invention comprises a matrix particle (first substance) made of a magnetic metal, a substance having high electric resistance and high magnetic permeability (second substance), and a second magnetic substance. It is composed of a fine particle size composite consisting of at least three kinds of substances having a high electric resistance (third substance) different from the substance, and the second substance almost covers the surface of the matrix phase particles. From a sintered body having a structure in which at least three layers in which the third substance substantially covers the second substance, and the matrix particles are substantially separated by the second substance and the third substance. Since it has such a structure, it is possible to reduce the thickness of the non-magnetic layer, and thus it is a composite magnetic body with high electrical resistance,
Moreover, a magnetic material having a high saturation magnetic flux density and a high magnetic permeability can be obtained.

In the above structure, the first substance is a Fe-based metal magnetic substance and the second substance is ferrite, so that the composite substance has a high electric resistance and a high saturation magnetic flux density. It is possible to easily provide a magnetic material having high magnetic permeability.

The composite magnetic material according to the second aspect of the present invention includes the matrix particles (first substance) made of magnetic metal, the substance having high electrical resistance (third substance), and the third substance. A fine particle size composite body composed of at least three kinds of substances having different electric resistances and high magnetic permeability (second substance),
The surface of the matrix particles is substantially covered with a third substance, and the second substance has a structure of at least three layers or more in which the third substance is substantially covered. Three
Since it has a structure composed of the sintered body and the sintered body substantially isolated by the second substance, the thickness of the non-magnetic layer can be reduced, and thus it is a composite magnetic body with high electric resistance. In addition, a magnetic material having high saturation magnetic flux density and high magnetic permeability can be obtained.

In the above structure, the first substance is a Fe-based metal magnetic substance and the third substance is ferrite, so that the composite substance has a high electric resistance and a high saturation magnetic flux density. , It is possible to easily provide a magnetic material having high magnetic permeability.

[0013]

Examples As the mother phase particles (first substance), magnetic metals or alloys having high saturation magnetic flux density, such as Fe, Fe-Al, Fe-Si, Fe-Si-Al, Fe- Si-Al-Ni, Fe-Ni, Fe-N
Fe-based magnetic materials such as i-Mo are desirable.

The particle size of these matrix particles (first substance) is usually preferably about 2 to 50 μm. The high electrical resistance and high magnetic permeability material (second material), for example, an electrical resistivity of 10 ⁰ Omega · cm in order or more, preferably one having 10 or more relative permeability, more specifically Examples include Ni-Zn ferrite and Mn-Zn ferrite.

When the composite magnetic material of the present invention is formed, the film thickness of the second substance is preferably about 20 to 1000 nm. Examples of the insulating high electric resistance substance (third substance) include Al—O, Si—O, and Al—N.
As the structure of the insulating layer, for example, a film made of two kinds of Al-0 and Al-N is considered, and in this case, two kinds of materials are the third material in the composite material made of four kinds of materials in total. Will have the same function.

The electrical resistivity of the third substance is, for example, 1
It is preferable to use one having an order of 0 ³ Ω · cm or more, and the third one in the case of constituting the composite magnetic material of the present invention.
The film thickness of the substance is preferably about 2 to 30 nm.

It should be noted that B ₂ O ₃ and Bi which have the same function as the third substance which can act as a liquid phase as an additive during sintering.
It is also useful to add ₂ O ₃ or the like to obtain a sintered body having high electric resistance.

3 comprising the above-mentioned first, second and third substances
In order to mold and sinter the composite powder of more than one layer into a predetermined shape, it is difficult to specify clearly because it depends on the type of each substance used, application, purpose, etc., but usually 200-800 kg
/ Cm ² and pressure molding, this molded body is usually 60
A sintered body can be formed by means of hot pressing at 0 to 1200 ° C. and about 300 to 2000 kg / cm ² for about 5 minutes to 10 hours.

Hereinafter, the present invention will be described in more detail with reference to specific examples. Example 1 The following experiment was carried out for the purpose of obtaining a magnetic material having a high magnetic permeability (μ> 2000 at 1 [MHz]) and a high saturation magnetic flux density (Bs> about 1 [T]) and a high electric resistance. I went.

Nitrogen atomized alloy powder (average particle size 30 μmφ) having a composition of 84 wt% Fe-10 wt% Si-6 wt% Al was used, and ph = 7-
It was immersed in an aqueous solution of NiCl ₂ and ZnCl ₂ adjusted to 8 at 70 ° C to react.

In the solution, the powder was adsorbed with metal ions and then oxidized in air to cause a ferritic reaction. These two reactions are performed at intervals of 1 to 2 minutes for 50 to 6
Alternating 0 times, soft magnetic Ni-Zn with a thickness of about 500 nm
A ferrite thin film was formed. This corresponds to a film of a high magnetic permeability material (second material).

The magnetic properties and electrical properties of the Ni-Zn ferrite thin film itself having a thickness of about 500 nm were evaluated using a thin film formed on a glass substrate. As a result, characteristics of the saturation magnetic flux density Bs = 3000 [G], the magnetic permeability μ = 121 (at 1 [MHz ]), was electrical resistivity ^{ρ = 10 5 ~10 9 [Ωcm} ].

Further, in order to form an insulating film, sputtering was performed in an atmosphere of nitrogen for 5 minutes with Al as a target to form an insulating film containing AlN as a main component and having a thickness of several nm on the powder surface.

After adding 0.1 vol.% Of B ₂ O ₃ as an additive to the composite Fe-Si-Al alloy powder, 500 kg /
After pressurizing with cm ² to make a molded body, 1000 ℃, 2 hours,
Hot press at a pressure of 500 kg / cm ² (in N ₂ ),
A high density (relative density 98-99%) composite sintered body was produced.

The magnetic properties of this composite material are shown in Table 1. Since the non-magnetic layers, AlN layer and B ₂ O ₃ layer, are as thin as 6 nm and have high electric resistance ρ> 10 ⁸ [Ωcm], the magnetic permeability in the high frequency range is high (μ = 2008 ( at 1 [MHz])) and the target magnetic material was obtained.

Example 2 As a magnetic material, as in Example 1, high magnetic permeability (μ> 20)
At the time of 00 at 1 [MHz]), the following experiments were carried out when the structure of the film was changed in order to obtain a magnetic material with a saturation magnetic flux density of Bs> about 1 [T] and a high electric resistance.

Nitrogen atomized alloy powder (average particle size: 30 μmφ) having a composition of 84 wt% Fe-10 wt% Si-6 wt% Al was heat-treated at 900 ° C. for 0.5 hour in a nitrogen atmosphere, and an insulation film having a thickness of 6 nm was formed. A film was formed. Further, in order to cover the powder with a film of a substance having a high magnetic permeability, the powder was immersed in an aqueous solution of NiCl ₂ and ZnCl ₂ at 70 ° C. adjusted to ph = 7 to 8 and reacted as in Example 1.

In the solution, powder adsorbs metal ions,
Next, it is oxidized in air to cause a ferritic reaction. By alternating these two reactions, a soft magnetic Ni-Zn ferrite thin film with a thickness of about 500 nm was formed.

Even for the composite Fe-Si-Al alloy powder having the three-layer structure (structure in which a film of a substance having a high magnetic permeability covers the insulating layer) this time, the same high pressing conditions as those in Example 1 were used. A composite sintered body of high density was produced.

Table 1 shows the magnetic characteristics of this composite material.
The saturation magnetic flux density is 1 [T], the magnetic permeability is μ = 2101 (at1MHz), the electric resistance is ρ = 3.2 × 10 ⁷ [Ωcm], and the high magnetic permeability is the same as in Example 1 even in the high frequency region. A magnetic material was obtained.

Comparative examples are shown below in order to show that the composite magnetic materials of Examples 1 and 2 are superior to the conventional composite magnetic material (sintered body of powder having a two-layer structure). Comparative Example 1 Nitrogen atomized alloy powder (average particle size 30 μmφ) having a composition of 84 wt% Fe-10 wt% Si-6 wt% Al was immersed in 70 ° C. aqueous solution of NiCl ₂ and ZnCl ₂ adjusted to pH = 7 to 8 , Reacted.

In the solution, the powder is allowed to adsorb metal ions,
Next, it is oxidized in air to cause a ferritic reaction. By alternating these two reactions, a soft magnetic Ni-Zn ferrite thin film with a thickness of about 500 nm was formed. This corresponds to a film of high magnetic permeability material.

The magnetic powder having this two-layer structure is 500 kg /
After pressurizing with cm ² to make a molded body, 1000 ℃, 2 hours, 500
Hot pressing was performed at a pressure of kg / cm ² (in N ₂ ) to produce a high density (relative density 98-99%) composite sintered body.

The magnetic properties of this composite material are shown in Table 1 as in the examples. Saturation magnetic flux density is 1 [T], permeability is μ = 2340 (at
100Hz), μ = 1241 (at1MHz), electric resistance ρ = 2.8 [Ωcm]
The value of was shown. Regarding the electric resistance, it was found that the magnetic permeability decreased in the high frequency region because a sufficiently high electric resistance value was not obtained.

In comparison with this comparative example, when 0.1 vol.% Of B ₂ O ₃ was added and hot press sintering was performed as in Example 1, the electric resistance of the sintered body was ρ = 4.1 [Ωcm. ], And a sufficient value was not obtained.

Comparative Example 2 A nitrogen atomized alloy powder (average particle size 30 μmφ) having a composition of 84 wt% Fe-10 wt% Si-6 wt% Al was used in a nitrogen atmosphere.
Heat treatment was performed at 900 ° C for 2.5 hours to form an insulating film with a thickness of 11 nm.

With respect to the composite Fe-Si-Al alloy powder having the two-layer structure, a high density composite sintered body was produced under the same hot pressing conditions as in Comparative Example 1. The magnetic properties of this composite material are shown in Table 1. Saturation magnetic flux density is 1 [T], permeability is μ = 1322 (at
100Hz), μ = 844 (at1MHz), electric resistance is ρ = 3.2 × 10 ^-1
The value of [Ωcm] is shown. The film thickness required to obtain a high magnetic permeability is at a level of 10 nm or less, and even if the powder covered with that film thickness is simply sintered, a high electric resistance cannot be obtained, and it rapidly increases in the high frequency region. It can be seen that the magnetic permeability has decreased.

[0038]

[Table 1]

[0039]

Industrial Applicability The composite magnetic material of the present invention is a composite magnetic material having a high electric resistance and can be a magnetic material having a high saturation magnetic flux density and a high magnetic permeability, and is a magnetic material excellent in high frequency characteristics. Can be provided.

Further, by adopting a preferable mode in which the first substance is an Fe-based metal magnetic substance and the second substance is ferrite, it is a composite magnetic substance having high electric resistance, high saturation magnetic flux density and high permeability. It is possible to easily provide a magnetic material having excellent high frequency characteristics of magnetic susceptibility.

Claims (4)

[Claims] 1. A matrix particle made of a magnetic metal (first substance), a substance having high electric resistance and high magnetic permeability (second substance), and a substance having high electric resistance different from the second substance (first substance). (3 substance), which is composed of at least three kinds of fine particle size composites, the second substance substantially covers the surface of the matrix phase particles, and the third substance almost covers the second substance. A composite magnetic material having a structure of at least three layers covering the parent phase particles, and the matrix particles are substantially separated from each other by the second substance and the third substance. 2. The composite material according to claim 1, wherein the first substance is an Fe-based metal magnetic body and the second substance is ferrite. 3. A matrix particle (first substance) made of a magnetic metal, a substance having high electric resistance (third substance), and a substance having high electric resistance and high magnetic permeability different from the third substance (first substance). 2 substance), which is composed of at least three kinds of fine particle size composites, the surface of the matrix particles is almost covered with the third substance, and the second substance almost covers the third substance. A composite magnetic material having a structure of at least three layers or more and covering the matrix particles substantially separated from each other by the third substance and the second substance. 4. The composite material according to claim 3, wherein the first substance is a Fe-based metal magnetic body and the third substance is ferrite.