JP3461516B2 - Oxide magnetic material - Google Patents

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 more particularly to an oxide magnetic material used as a magnetic core material such as a line filter.

[0002]

2. Description of the Related Art It is well known that ferrite, which is an oxide magnetic material, is widely used as a magnetic core for various winding parts such as transformers and filter elements, and is incorporated in various electronic devices. There is a strong demand for downsizing and cost reduction of electronic devices in recent years, and winding parts are no exception.

On the other hand, as a magnetic core material for a line filter or the like, improvement and stabilization of initial magnetic permeability are required as electromagnetic characteristics in order to reduce size and weight. In response to this request
Manganese zinc ferrite with silicon dioxide (SiO ₂ ),
It is already known that the initial permeability is improved by controlling calcium oxide (CaO).
The line filter magnetic core is generally fixed to the terminal board with an adhesive after the magnetic core is wound.

[0004]

However, when the line filter magnetic core is adhered to the terminal board after winding and a long time has passed, a low load long-term stress is applied to the line filter magnetic core due to hygroscopic expansion of the terminal board. , Cracks in the magnetic core often cause problems.

Therefore, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an oxide magnetic material having improved strength against low load long-time stress without deteriorating electromagnetic characteristics. To aim.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 uses SiO ₂ of 100 to 200.
of manganese-zinc ferrite containing 250 to 900 ppm of Ca and 250 to 900 ppm and P of 2 to 50 pp
m ₂ and TiO ₂ are contained at 750 to 3000 ppm .

According to a second aspect of the invention, in the oxide magnetic material according to the first aspect, Ta ₂ O ₅ is added in an amount of 50 to 8
The content is 00 ppm .

[0008] The invention of claim 3, wherein the Te oxide magnetic material odor according to claim 1, _Nb 2 _{O 5} and 20 to 4
The content is 00 ppm.

[0009]

According to the invention described in claim 1, SiO ₂ , Ca
The manganese zinc ferrite containing O in the above proportions has a composition belonging to the high magnetic permeability composition range, so that the initial magnetic permeability of the magnetic core does not deteriorate. Further, by containing P and TiO ₂ in the above proportions in this manganese zinc ferrite, the strength against a low load long-term stress can be improved.

According to the invention described in claim 2, in the oxide magnetic material according to claim 1, Ta ₂ O in the above ratio
By further containing ₅ , the strength against the low load long- term stress is further improved as compared with the invention of claim 1 .

According to the invention of claim 3 , in addition to the effect of the invention of claim 1 , a predetermined amount of Nb ₂ O ₅ is contained.
As a result, the strength against the above-mentioned low load long-term stress is guaranteed.
It is further improved as compared with the invention of claim 1 .

[0012]

EXAMPLES Examples of the present invention will be described in detail below.

The oxide magnetic material of the first embodiment of the present invention contains silicon dioxide (SiO ₂ ) of 30 to 200 ppm.
And calcium oxide (CaO) 250 to 900pp
In the manganese zinc ferrite containing m, phosphorus (P) as an additive is 100 ppm or less (excluding 0 ppm) and titanium oxide (TiO ₂ ) is 3000 ppm or less (0 ppm is
It is included) .

In order to obtain, for example, a magnetic core for a line filter from the above oxide magnetic material, powders in the above proportions are prepared, mixed with each other, calcined at 900 ° C., and pure water is used. Wet grinding is performed. Next, it is molded into a predetermined shape (for example, a Japanese letter) by a press molding machine. Then 136
A line filter magnetic core can be obtained by firing at 0 ° C. for 3 hours in a mixed gas of air and N ₂ .

[0015] The manganese zinc ferrite, which is a base material, there is no problem in any way in any composition as long as the composition range. With such a composition, a high magnetic permeability material can be obtained.

The additive material (P, TiO ₂ ) may be added either before or after calcination in the material manufacturing process. Further, it may be contained in the raw material. Further, the additive material is not limited to the oxide, and may be phosphorus alone, a metal compound such as phosphoric acid, phosphate, carbonate or hydroxide.

The case where only the additive P is contained will be described with reference to FIGS. 1 and 2.

FIG. 1 shows P when only P is used as an additive.
Is a measurement result showing the relationship between the ratio of the load and the low load long time load.

The material is iron oxide (F
e ₂ O ₃ ) 52.8 mol%, zinc oxide (ZnO) 21.
2 mol%, manganese oxide (MnO) 26.0 mol%, silicon dioxide _(SiO 2) 100 ppm, prepared powder mixing ratio consisting of calcium oxide (CaO) 350ppm, 2pp m乃 the P contrast It is changed in the range of up to 150 ppm.

The test product was prepared by mixing the above materials, and
Preliminary calcination at 00 ° C, wet pulverization using pure water, and molding into a day shape with a press molding machine, 136
Firing at 0 ° C. in a mixed gas of air and N ₂ for 3 hours (external dimension) 35 × 35 mm (window dimension) 9.75 × 2
A 7-mm day-shaped core was obtained.

The measuring method is as follows: 1 μm / min
The tensile strength was measured.

According to the measurement result shown in FIG. 1, the low load long-time load was 12. When the base material ferrite alone without the additive material P was added. It is 8 kgf, but it can be seen that it decreases as P is added.

FIG. 2 shows the measurement results showing the relationship between the P ratio and the initial magnetic permeability when only the additive material P is used. A ring-shaped core was molded with a molding machine to measure the initial magnetic permeability, and the core was fired at the same time as the letter with the letter of the date.
A ring-shaped magnetic core having a height of 6 mm and a height of 6 mm is used.
The measurement conditions are as shown in Table 1.

[0024]

[Table 1] Initial permeability measurement conditions Initial permeability, the content of the additive material P reaches a peak at 50 ppm, .mu.i becomes high as 6300 in the range of 2pp m乃 optimum 100ppm centered on this, which is preferable as a magnetic material.

A case where only the additive TiO ₂ is contained will be described with reference to FIGS. 3 and 4.

As the material, powder having the same composition of the base material ferrite as that used in the description of the P content was prepared, and TiO ₂ was changed in the range of 0 (no addition) to 5000 ppm. It was made. The test product and the measuring method are the same as those described for the P content.

According to the measurement results shown in FIG. 3, the low load long-time load is 12.8 kgf for the base material ferrite alone to which the additive TiO ₂ is not added, but 100 ppm or more of TiO ₂ should be added. by, it can be seen that became strongly.

The initial permeability is similar to that of low load and long time load,
The base material ferrite alone, to which the additive TiO ₂ was not added, had a μi of 6300, but the additive TiO ₂ was 10
By adding 0 ppm or more and 3000 ppm or less,
It is preferable as a magnetic material.

Next, the effect of the oxide magnetic material having the above structure will be described with reference to Table 2.

[0030]

[Table 2] Table 2 shows the relationship between the ratio of P and TiO ₂ when P and TiO ₂ were added as additive materials, the low load long-time load, and the initial magnetic permeability.

The material is iron oxide (F
e ₂ O ₃ ) 52.8 mol%, zinc oxide (ZnO) 21.
2 mol%, manganese oxide (MnO) 26.0 mol%, silicon dioxide (SiO ₂ ) (30, 100, 200) pp
m, calcium oxide (CaO) (250, 450, 90
0) Prepare powder with a compounding ratio of ppm, and change P in the range of 2 ppm to 150 ppm,
TiO ₂ was changed in the range of 0 ppm (no addition) to 5000 ppm.

Data 1 , 2 , 6 , 9, 10, shown in the table
11 corresponds to the present invention. Other data is,
The reference data is shown. As shown in the table, P as an additive material
By containing TiO ₂ and TiO ₂ , the strength against a long-term low-load stress is high, the initial permeability is high, and it is preferable as a magnetic material. Therefore, when the oxide magnetic material having such a composition is used as the core, the strength of the core against stress under a low load for a long time can be improved without deterioration of the electromagnetic characteristics. Core cracking due to expansion can be reduced. In addition,
As described above, the inclusion of P and TiO ₂ was found to improve the strength against long-term low-load stress, focusing only on the strength against long-term low-load stress and conducting experiments using various ferrites. As a result, when the strength against low stress and long time stress is weak, the fracture is mostly performed inside the crystal grain, whereas when the strength against low stress and long time stress is strong, the fracture is at the grain boundary. It has become clear.

The oxide magnetic material of the second embodiment of the present invention comprises SiO ₂ of 30 to 200 ppm and CaO of 25.
Manganese zinc ferrite containing 0 to 900 ppm, P as an additive is 100 ppm or less (excluding 0 ppm).
, TiO ₂ less than 3000ppm (excluding 0ppm )
) And Ta ₂ O _{5 in an amount} of 50 to 800 ppm.

According to the oxide magnetic material of the second embodiment, as shown in Table 3, the same effects as those of the first embodiment can be obtained, and the strength against the long-term low load stress can be obtained .
Further improvement can be achieved.

[0035]

[Table 3] Table 3 shows that SiO ₂ is 100 ppm and CaO is 450 ppm.
In the manganese zinc ferrite containing ppm, P is added as an additive material in an amount of 50 ppm and TiO ₂ is included in 750 ppm,
Further, 100 to 800 ppm of Ta ₂ O ₅ is contained. In addition, data 1 to data 4 shown in the table are
This corresponds to the present invention, and data 5 is reference data.

The oxide magnetic material of the third embodiment of the present invention contains SiO ₂ of 30 to 200 ppm and CaO of 25.
Manganese zinc ferrite containing 0 to 900 ppm, P as an additive is 100 ppm or less (excluding 0 ppm).
, TiO ₂ less than 3000ppm (excluding 0ppm )
) And Nb ₂ O _{5 in an amount} of 20 to 400 ppm.

According to the oxide magnetic material of the third embodiment, as shown in Table 4, the same effects as those of the first embodiment can be obtained, and the strength against the low load long-term stress can be obtained .
Further improvement can be achieved.

[0038]

[Table 4] Table 4 shows that SiO ₂ is 100 ppm and CaO is 450 ppm.
In the manganese zinc ferrite containing ppm, P is added as an additive material in an amount of 50 ppm and TiO ₂ is included in 750 ppm,
Further, it contains 50 to 400 ppm of Nb ₂ O ₅ . Further, data 1 to data 4 shown in the same table correspond to the present invention, and data 5 are reference data.

[0039]

According to the invention described in claim 1, which has been described in detail above, manganese zinc ferrite has a composition belonging to a high magnetic permeability composition range, and P and TiO ₂ which can contribute to the improvement of strength against a low load long-term stress. Since a predetermined amount is contained, it is possible to provide an oxide magnetic material having improved strength against low load long-term stress without deteriorating the initial magnetic permeability which is an electromagnetic characteristic.

According to the second aspect of the invention, a predetermined amount of T
By further containing a ₂ O ₅ , low load long-term stress
The strength against is further improved as compared with the invention of claim 1 .

According to the invention of claim 3 , in addition to the effect of the invention of claim 1 , a predetermined amount of Nb ₂ O ₅ is further contained.
By strength against the low load prolonged stress claims
It is further improved as compared with the invention of Item 1 .

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the low load long-time load and the phosphorus content when phosphorus is contained in a composition of manganese zinc ferrite.

FIG. 2 is a graph showing the relationship between the initial magnetic permeability and the phosphorus content when phosphorus is contained in the composition of manganese zinc ferrite.

[3] low load long load and titanium oxide when the content of the titanium oxide in the composition consisting of manganese zinc ferrite
It is a graph which shows the relationship with the content of tongue .

FIG. 4 is a graph showing the relationship between the initial permeability and the content of titanium oxide when titanium oxide is contained in the composition of manganese zinc ferrite.

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Claims (3)

(57) [Claims] 1. A manganese zinc ferrite containing 100 to 200 ppm of SiO ₂ and 250 to 900 ppm of CaO as a base material, P of 2 to 50 ppm , and TiO 2.
_2. An oxide magnetic material containing ₂ to 750 to 3000 ppm . Wherein the oxide magnetic material of claim 1, wherein the Ta ₂ O ₅ containing 50 to 800 ppm. Wherein the oxide magnetic material of claim 1, wherein the Nb ₂ O ₅ containing 20 to 400 ppm.