JPH08339913A - Oxide magnetic material and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide the oxide magnetic material suitable for the constitution of a magnetic core for an antenna coil and an inductance element for electronic equipment used in the high-frequency band of 200-500MHz such as pagers (pocket bells) and the like. CONSTITUTION: This is the oxide magnetic material for the magnetic core of a coil used in a high-frequency band. The compositions of the base material at the sintering are Fe2O3: 15-30mol%, CuO: 6-12mol% and Nip: 58-79mol%. With the total quantity of the base material as the reference, the adding components of PbO: 1.0-5.0wt.%, SiO2: 0.5-3.7wt.% and Cod: 0.7-2.5wt.% are contained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxide magnetic material and a method for producing the same, and, for example, a pager (pager) for which demand is high, and the like.
The present invention relates to an oxide magnetic material suitable for forming a magnetic core for an antenna coil or an inductance element used in an electronic device used in a high frequency band of 500 MHz, and a manufacturing method thereof.

[0002]

2. Description of the Related Art An oxide magnetic material for forming this kind of magnetic core is a bandpass filter for electronic equipment used in a high frequency band of 200 MHz or more, as disclosed in, for example, Japanese Patent Laid-Open No. 63-169005. It is used in magnetic cores for inductance elements such as.

A loop antenna (air core coil) is usually used as the antenna coil for the pager. However, such a loop antenna has a Q
Although it has a high advantage, it is difficult to adjust the characteristics such as inductance, and it is apt to change due to an external force such as vibration. Further, in order to increase the inductance, it is necessary to increase the number of windings of the winding, but there is also a drawback that the size is increased as a whole.

On the other hand, the above-mentioned Japanese Patent Laid-Open No. 63-1690.
A coil with a magnetic core made of an oxide magnetic material as disclosed in Japanese Patent Publication No. 05 has the advantage of being easy to adjust the inductance and suitable for downsizing, but has the drawback of low Q. . The Q value of the oxide magnetic material at 280 MHz in the above publication is 170.
Including the above, some Q values at 280 MHz were measured, and the results shown in Table 1 of FIG. 6 were obtained. Thus, the conventional oxide magnetic material has a low Q value and is not suitable for use as an antenna coil.

[0005]

SUMMARY OF THE INVENTION As described above, as described above,
A loop antenna is usually used in an electronic device such as a pager, but it has an advantage of high Q but tends to be large in size as a whole. If a coil with a magnetic core made of a material is used, it is suitable for downsizing, but there is a problem that Q is low.

An object of the present invention is to solve such a problem, and an oxide magnetic material capable of obtaining a higher Q in a magnetic core made of an oxide magnetic material such as the latter, and the same. It is intended to provide a manufacturing method.

[0007]

The present invention has been made to achieve the above object, and the oxide magnetic material according to the present invention according to claim 1 is for a magnetic core of a coil used in a high frequency band. Fe oxide, an oxide magnetic material of
2O3: 15 to 30 mol%, CuO: 6 to 12 mol
%, And NiO: 58 to 79 mol% as main components, P
bO: 1.0 to 5.0 wt%, SiO2: 0.5 to 3.
7 wt% and CoO: 0.7 to 2.5 wt% are included as additional components.

According to a second aspect of the present invention, there is provided a method for producing an oxide magnetic material according to the present invention, which is an oxide magnetic material for a magnetic core of a coil used in a high frequency band, wherein
2O3: 15 to 30 mol%, CuO: 6 to 12 mol
%, And NiO: 58 to 79 mol% as a main component, PbO: 1.0 to 5.0 wt%, Talc: 1.0
.About.5.5 wt% and CoO: 0.7 to 2.5 wt% are added and fired.

An antenna coil according to a third aspect of the present invention is characterized by using the magnetic core made of the oxide magnetic material according to the first aspect.

According to a fourth aspect of the present invention, an inductance element according to the present invention uses the magnetic core made of the oxide magnetic material according to the first aspect.

This invention is described in the above-mentioned JP-A-63-169005.
Although it overlaps with the invention of the publication, a composition range of a high Q value, which was not obtained in the above invention, was discovered, and
This is a so-called selection invention, which is limited to the part where the value can be obtained.

[0012]

The oxide magnetic material according to the present invention according to claim 1 is manufactured based on the method for manufacturing an oxide magnetic material according to claim 2. However, in claim 2, SiO 2 is used as an additive material instead of SiO 2. The use of Talc is for cost reduction. Here, Talc is Mg3 (Si4O
10) Since it is composed of (OH) 2, a small amount of MgO remains after firing, but it has almost no effect on the characteristics.
A high Q is obtained in the frequency band of ˜500 MHz.

Claims 3 and 4 are inventions relating to an antenna coil and an inductance element, respectively.
Since the magnetic core made of the oxide magnetic material according to claim 1 is used, a high Q can be realized in a high frequency band.

[0014]

【Example】

[Example 1] By a conventional method, the base material and the additive of [A] described later were mixed, pre-baked, crushed, and pressed into a desired shape (such as a rod-shaped core) → (900 to 10).
Calcination was performed at a predetermined temperature (such as 00 ° C.) for the required time (about 2 hours).

[A]: As a base material composition: Fe2O3: 15
-30 mol%, CuO: 6-12 mol%, Ni
O: 58 to 79 mol%, and as an additive component (when the total amount of the base material is taken as a reference (100 wt%)): PbO: 3.0 wt%, SiO
2: 1.7 wt%, CoO: 1.0 wt%, and the resulting rod-shaped core (21 mm x 9 mm x 5.5 mm) made of an oxide magnetic material is tin-plated annealed copper foil. After winding (1.3 mm × 0.25 mm) for 2 Ts and measuring the Q value at 280 MHz using an impedance analyzer, the results shown in Table 2 of FIGS. 1 and 5 were obtained. . Such a high Q value has not been confirmed in the above-mentioned Japanese Patent Laid-Open No. 63-169005 and is the first discovery in the present invention.

[Example 2] Next, within the composition range of the main component clarified in [Example 1], Fe2O3: 23mo
1%; CuO: 9 mol%; NiO: 68 mol% are fixed and fixed with added components (PbO; Talc (effective SiO2 component); CoO) and PbO: 0.5-6.
0 wt%, Talc 0.6 to 8.0 wt% (SiO2:
0.3-4.0 wt%), CoO: 0.5-3.0 wt
2 to 4 were obtained by varying in the range of%. The methods such as molding, firing, winding, and measurement here are the same as those in [Example 1]. And, as is apparent from FIGS. 2 to 4, the Q value of 250 or more is obtained by PbO: 1.0 to 5.0 wt%, Talc: 1.0 to
5.5 wt%, (SiO2 as an active ingredient: 0.5-
3.7 wt%) CoO: 0.7 to 2.5 wt%.

Although a little MgO remains in this [Example 2], the amount of MgO is not so large as to impair the characteristics, and is as high as that of the oxide magnetic material in [Example 1]. Q was obtained. In this [Example 2], unlike the case of the above-mentioned [Example 1], Talc, which is cheaper than SiO2 alone, is selected as one of the additive components at the start of firing. Therefore, in addition to achieving a Q value comparable to that in the case of [Example 1], there is a remarkable advantage that it also benefits economically.

An antenna coil and an inductance element for an electronic device such as a pager are constructed by using the magnetic cores made of the magnetic material of [Example 1] and [Example 2], and a desired high Q is realized. We were able to.

FIG. 2 shows a first example of the oxide magnetic material.
FIG. 5 is an explanatory diagram of the influence on the Q value based on the variation of the addition amount of PbO, which is the addition component of P. In FIG. 2, 21 is Pb
It is an O addition amount variation curve, PbO with a Q value of 250 or more.
The effective addition range is 1.0 to 5.0 wt%.

FIG. 3 shows a second example of the oxide magnetic material.
FIG. 6 is an explanatory view of the influence on the Q value based on the variation of the addition amount of SiO 2 which is the addition component of the above. In FIG. 3, 31 is S
It is a variation curve of the amount of addition of iO2, and the effective addition range of SiO2 is 0.5 to 3.7 wt%.

FIG. 4 is an explanatory view of the influence on the Q value based on the variation of the addition amount of CoO which is the third addition component to the oxide magnetic material. In FIG. 4, 4
Reference numeral 1 denotes a CoO addition amount variation curve, and the effective addition range of CoO is 0.7 to 2.5 wt%.

[0022]

As described above, the oxide magnetic material according to the present invention contains Fe2O3: 15 to 30 mol%, C
uO: 6-12 mol%, and NiO: 58-79mo
1% as a main component, PbO: 1.0 to 5.0 wt%, S
iO2: 0.5 to 3.7 wt%, and CoO: 0.7 to
By containing 2.5 wt% as an additive component, it is possible to obtain a high Q in the frequency band of 200 to 500 MHz, for example.

In the method for producing an oxide magnetic material according to the present invention, the base material composition at the start of the production is Fe2O3: 1.
5-30 mol%, CuO: 6-12 mol%, and N
iO: 58 to 79 mol%, PbO: 1.0 to 5.0 wt%, Talc: 1.
0-5.5 wt% and CoO: 0.7-2.5 wt%
Is added as an additional component, and Talc, which is one of the additional components, is included in the sintering process when SiO2: 0.5 to 3.7 wt.
% And a little MgO is deformed and remains, but MgO here does not cause a problem in characteristics, and TaCl which is cheaper than SiO2 as a simple substance is used and the oxide magnetic material according to claim 1 is used. This has the effect of obtaining a high Q that is almost the same as the above.

Further, a desired high Q value can be realized by using the magnetic core made of the oxide magnetic material obtained as described above to construct an antenna coil or an inductance element for electronic equipment such as a pager. Has the effect.

[Brief description of drawings]

FIG. 1 is an explanatory view of the influence of the oxide magnetic material according to the present invention on the Q value based on the variation of the base material composition (Fe2O3, CuO, NiO).

FIG. 2 is an explanatory diagram of the influence on the Q value based on the variation of the added amount of PbO, which is one of the added components to the oxide magnetic material.

FIG. 3 is an explanatory diagram of the influence on the Q value based on the variation of the added amount of SiO 2 which is one of the additive components to the oxide magnetic material. And

FIG. 4 is an explanatory diagram of the influence on the Q value based on the variation of the added amount of CoO, which is one of the additive components to the oxide magnetic material.

FIG. 5 is a table (Table 2) for explaining the effect of the present invention.

FIG. 6 is a table (Table 1) for explaining a conventional example.

[Explanation of symbols]

 11: Fluctuation line segment of Fe2O3; 12: Fluctuation line segment of CuO; 13: Fluctuation line segment of NiO; 21: PbO addition amount variation curve; 31: SiO2 addition amount variation curve; 41: CoO addition amount variation curve ;

Claims (4)

[Claims] 1. An oxide magnetic material for a magnetic core of a coil used in a high frequency band, comprising Fe ₂ O ₃ : 15 to ₃₀ mo.
1%, CuO: 6-12 mol%, and NiO: 58-
79 mol% as a main component, PbO: 1.0 to 5.0 w
_{t%, SiO 2: 0.5~3.7wt%} , and CoO:
An oxide magnetic material containing 0.7 to 2.5 wt% as an additive component. 2. A method of manufacturing an oxide magnetic material for a magnetic core of a coil used in a high frequency band, comprising Fe ₂ O ₃ : 15.
-30 mol%, CuO: 6-12 mol%, and Ni
O: 58-79 mol% as a main component, PbO:
1.0-5.0 wt%, Talc: 1.0-5.5 wt
%, And CoO: 0.7 to 2.5 wt% are added and fired. 3. An antenna coil using the magnetic core made of the oxide magnetic material according to claim 1. 4. An inductance element using the magnetic core made of the oxide magnetic material according to claim 1.