JPS6142105A - Manganese-zinc system ferrite material and magnetic core for high frequency power supply transformer - Google Patents

Abstract

PURPOSE:To obtain high permeability and low loss characteristic by forming a manganese-zinc system ferrite material through inclusion of calcium oxide, silicon oxide, niobium oxide, bismuth oxide and/or indium oxide and potassium oxide. CONSTITUTION:A manganese-zinc system ferrite material is formed through inclusion of calcium oxide, silicon oxide, niobium oxide, bismuth oxide and/or indium oxide and potassium oxide. Calcium oxide is 0.03-0.2wt% in terms of CaCO3, silicon oxide is 0.001-0.05wt% in terms of SiO2, niobium oxide is 0.001- 0.1wt% in terms of Nb2O5, bismuth oxide and/or indium oxide is 0.001-0.1wt% in terms of Bi2O3 and/or In2O3 and potassium oxide is 0.3wt% or less in terms of K2CO3.

Description

BACKGROUND OF THE INVENTION Technical Field The present invention relates to a manganese-zinc ferrite material with low power loss and a magnetic core for a power transformer that operates at a high frequency of about 10 to 1000 z. , relates to a magnetic core for a high-frequency power transformer formed therefrom.

Prior art and its problems Manganese-zinc ferrites are widely used as coils and transformer materials in various communication devices and consumer devices, but recently there has been a trend toward using high-frequency power supplies.
Performance as a transformer material is increasingly required for this purpose.

Especially for video decks, various OA equipment, etc., 10
There is a need for transformer materials that can supply a variety of stable voltages for motor drives, signal amplification, transmission, etc., which are used with several LOW power in the high frequency range of KHz - 100K)lz.

One of the properties required of manganese-zinc ferrite as a transformer material is high magnetic permeability.

However, conventional manganese-zinc based high magnetic permeability ferrites have large power and loss in the high frequency range of about 10 KHz to 100 KHz, and improvements in terms of loss are required.

- By the way, it is known that the power loss of a normal transformer coil material can be reduced by adding potassium or sodium to a manganese-zinc ferrite material (for example, Japanese Patent Publication No. 53-28833).

In this case, the amount of potassium added is 0.03wt% in terms of
It is as follows.

However, the operating frequency of about 10 KHz to 100 KHz causes a large power loss and is insufficient for practical use.

On the other hand, reducing power loss generally reduces magnetic permeability, so it is desirable to use ferrite magnetic materials for power transformers that have low power loss in high frequency ranges without reducing magnetic permeability.

II. OBJECTS OF THE INVENTION The object of the present invention is to develop a novel manganese material with high magnetic permeability and low loss.
The purpose of the present invention is to provide zinc-based ferrite magnetic materials and magnetic cores for high-frequency power transformers.

Such objects are achieved by the invention described below.

That is, the first invention is as follows.

A manganese-zinc based ferrite material containing calcium oxide, silicon oxide, niobium oxide, bismuth oxide and/or indium oxide, and potassium oxide.

Further, a second invention provides a high frequency power source characterized by being made of a manganese-zinc ferrite material containing calcium oxide, silicon oxide, niobium oxide, bismuth oxide and/or indium oxide, and potassium oxide. This is a magnetic core for transformers.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

The manganese-zinc based ferrite magnetic material in the present invention has iron oxide, manganese oxide and zinc oxide as main components.

These main components are respectively 52-54 mole 1/% in terms of Fe2O3, 28-33 mole% in terms of MnO, and 713-20 mole% in terms of ZnO.

Outside this range, a single point of Curie will be below 100℃, or
Alternatively, ga decreases in the high frequency region.

In this case, iron oxide is 52.5 to 53.5 mol% in terms of Fe2O3, and mankan oxide is M n O
Converted 'tl'29, 0-31, 5 mol%, zinc oxide 15.0-18. It is even more preferable that it is %.

In addition to these main components, the magnetic material of the present invention contains calcium oxide, silicon oxide, niobium oxide, bismuth oxide or indium oxide, and potassium oxide.

In this case, calcium oxide, silicon oxide, niobium oxide,
The content of each component of bismuth oxide, indium oxide, and potassium oxide is -(0.03 to 0.2 wt% in terms of CaCO3, 0 in terms of SiO2).
, 001-0.05wt%, 0.00% in terms of Nb2O5.
001-0.1wt%, Bi2O3 or In2O3
It is preferably 0.001-0.1wt%1 in terms of conversion and 0.3 or less in terms of K2CO3.

In the ferrite of the present invention, calcium oxide is a component that reduces loss in the high frequency range, but o, o3ffi
When it is less than 1%, its effectiveness is lost, and when it exceeds 0.2%, the magnetic permeability decreases.

In this case, the calcium oxide content is 0.04 to 0.08
When it comes to heavy background %, even more favorable results are obtained.

Silicon oxide is also a component that reduces loss in the high frequency range, but if it is less than 0.001 wt%, it becomes ineffective.
Moreover, if it exceeds 0.05 wt%, the loss will increase.

In this case, the silicon oxide-containing powder is o, ooa ~ 0.025
When it comes to wt%, even more favorable results can be obtained.

Niobium oxide is also a component that reduces loss in the high frequency range, but if it is less than 0.001 wt%, it becomes ineffective.
Moreover, if it exceeds 0.10 wt%, the loss will increase.

In this case, the niobium oxide content is 0.01 to 0.04wt
%, even more favorable results can be obtained.

Furthermore, bismuth oxide is a component that increases magnetic permeability.

The magnetic permeability is improved by containing bismuth oxide in the above-mentioned equation, but 0.
If it becomes less than 0.001wt%, its effectiveness disappears, and the
, when it exceeds 10 wt%, the magnetic permeability decreases.

In this case, the bismuth oxide content is 0.01 to 0.08w
When it comes to t%, even more favorable results can be obtained.

Furthermore, indium oxide also improves magnetic permeability, but its content is 0.10 wt% or less, especially 0.0
01 to 0.10 wt%, more preferably 0.01 to 0.01 wt%.
05. It is wt%.

These indium oxide and bismuth oxide may be added individually, or both may be added.

When both are added, there is no restriction on the ratio, and the total amount is 0.001 to 0.10% by weight.

Furthermore, potassium oxide also has a loss reducing effect.

In this case, when adding potassium oxide, the power loss increases with the addition amount up to 0.12 wt%, and if it is added more than this, it deteriorates, and if it exceeds 0.3 wt%, it is not practical, and if it is less than 0.01 wt%. It cannot be effectively changed.

Potassium oxide content: Crab 2 CO3 equivalent, 0.03~
When it is 0.2 wt%, especially 0.07 to 0.19 wt%, loss is low and magnetic permeability is high, and even more favorable results can be obtained.

In order to contain potassium oxide, 2 CO3 is added, which controls the growth of abnormal grains and adjusts the particle size. By making the particle diameters uniform, the magnetic properties, especially the residual magnetic flux density, decrease, the coercive force decreases, and the hysteresis loss decreases. child
Therefore, power loss is reduced.

In the ferrite material of the present invention, 50°C1 sine wave 25K
Hz, 2O0 oct, 70mW/C1l
”In particular, low power losses of up to 60 mW/cm 3 can be achieved.

Moreover, the magnetic permeability pa reaches 9000 or more.

A magnetic core for a power transformer made of such a ferrite material operates at a frequency of 10 to 100 KHz, and its power is approximately 10 to 100 W.

The shape, dimensions, etc. thereof are known.

The ferrite material and magnetic core of the present invention are manufactured according to conventional methods.

That is, first, in producing manganese-zinc ferrite, 0.03 to 0.2 wt% of calcium carbonate and 0.00% of silicon oxide are added as trace components to the raw material mixture.
1-0, 05wt% or less, niobium oxide 0.001-0
．． 1wt%, bismuth oxide and/or indium oxide 0.001-0.1wt%, potassium carbonate 0.3wt
% or less, respectively.

As the main component in the present invention, a mixture of a usual iron oxide component, manganese oxide component and zinc oxide component is used.

These main components each account for 52 to 54 mol%, especially 52.5 to 5 mol% in terms of Fe2O3, as the final composition of the magnetic material.
3.5 mol%, 28 to 33 mol% in terms of MnO, especially 29 to 31.5 mol%, 13 to 20 mol% in terms of ZnO,
In particular, they are mixed at a ratio of 15 to 18 mol% and used as a raw material.

On the other hand, the raw materials for trace components contained in the magnetic material of the present invention are calcium carbonate, silicon oxide, niobium oxide, bismuth oxide and/or indium oxide, and potassium carbonate, and these are used as raw material mixtures. added inside.

In order to suitably produce a desired magnetic material according to the present invention, first, the main component and the added minor component are mixed, and a small amount of a suitable chisel binder, such as polyvinyl alcohol, is added thereto, for example, 0.1 to 1.0 wt%. Mold.

Next, this molded product is usually heated to 800 to 100% under atmospheric pressure.
up to a predetermined temperature within the range of 0°C, e.g. 300°C/hr
After rapid heating at a certain rate of temperature increase, the temperature is maintained for a certain period of time, preferably one hour or more.

Next, in an atmosphere with a controlled boromine concentration, the material is gradually heated to a desired sintering temperature at a temperature increase rate of 50 to 100 μm, and sintering is completed at that temperature.

The firing atmosphere at this time is preferably a nitrogen atmosphere in which the oxygen concentration is controlled to about 1 to 15%.

And firing is usually done in such an atmosphere at 1350~
This is carried out by maintaining a predetermined temperature in the range of 1400° C. for 1 to 4 hours.

The cooling process after sintering is completed in this way is carried out in an atmosphere where the oxygen concentration is controlled according to the temperature from the sintering temperature to about 1200°C, and thereafter in an inert atmosphere, for example, a nitrogen atmosphere. is preferable, and the cooling rate is 5
00 to 700°C, about /hr is preferable.

In this way, by setting a constant temperature condition at an appropriate temperature between 800 and 1000 degrees Celsius for a predetermined period of time, especially one hour or more, and then performing sintering in an atmosphere with a controlled oxygen concentration, high-frequency region Extremely high performance characteristics such as high magnetic permeability and low loss can be obtained.

■Specific effects of the invention The manganese-zinc ferrite of the present invention has high magnetic permeability in a relatively high frequency range of 10 KHz to 1 OOKHz,
Moreover, since it has the characteristic of low loss, it is useful as the magnetic core of a transformer with an output of several watts to several 10 watts for OA@dexterity, etc.

Moreover, such characteristics are realized over a wide temperature range.

In this case, as will become clear from the examples described later, if even one essential component of the present invention is missing, a high magnetic permeability improvement effect and a high loss reduction effect cannot be obtained.

(2) Specific Examples of the Invention Hereinafter, specific examples of the present invention will be shown and the present invention will be explained in more detail.

<Example 1> Mn0 (30.8 mol%), Z'n0 (16.4 mol%), Fe2O3 (52.8 mol%)
is the main component, and the subcomponents are CaCO30, O55vt%, Nb2O30.02wt.
%, SiO2O,02wt%, In2O30,03wt
%, and further 0.03 wt% of 2C03, 0.0
6wt%, 0.10wt%, 0.15vt%, 0. '2
The power loss ■-/C■3 and magnetic permeability #La at 50° C. when added at wt% were measured and shown in Table 1 and FIG. 1. The firing temperature was 1360° C.

The power loss was measured under the conditions of a 25 KHz sine wave and 200 Gauss.

Table 1 From the results shown in Table 1 and FIG. 1, it can be seen that the addition of K2 co3 improves power loss and Ba.

Furthermore, when we investigated the temperature-dependent changes in power loss (Figure 2) and the temperature-dependent changes in magnetic permeability (Figure 3) of these ferrite materials, we found the results shown.

From Figure 2, the power loss and pa are as follows in a wide temperature range:
It can be seen that the condition is extremely good.

Furthermore, in Figures 4, 5, and 6, K2
CO30, 03vt%, 0.06wt%, 0.10vt
An optical microscope photograph (magnification x 350) of the grain growth of the ferrite material in the case of containing %.

This shows that the addition of K2co3 suppresses abnormal grain growth, adjusts the grain size, and contributes to improving magnetic properties.

Further, the saturation magnetic flux density, residual magnetic flux density, coercivity, and force of the sample prepared in Example 1 are shown in Table 2.

The measurement was carried out under the conditions of 5000 Gauss and 150e.

Table 2 shows 2CO3Bs BrΔB Hc (wt$) (G) (G) (G) (Oe)0.
03 5180215030300.12O0.08
5225185033750.12O0, +0 521
018053405 o:'ttt0.1552O0+
80034000.1030.2O 52101840
33700.105 From the results shown in Table 2, K2 C
By adding O3, a decrease in residual magnetic flux density and a decrease in coercive force are observed, and hysteresis loss is reduced. It can be seen that this is a contributing factor to the increase in power loss.

<Example 2> For further comparison, Mn0 (30.8 mol%), Z
nO (16,4 mol%), Fe2O3 (52,8
mol%) as the main component, and changing the subcomponents as shown in Table 3,
Power loss and g& were similarly measured for the manganese-zinc ferrite under the same firing conditions as in Example 1.

The results are shown in Table 3.

From the results shown in Table 3, the sample of the present invention shows a loss reduction rate of 30% or more and a magnetic permeability improvement rate of about 20% or more,
It can be seen that the overall performance is extremely good.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the power loss at 50° C. of Hue and Light of Example 1 and the amount of 2 CO3 added. FIG. 2 is a graph showing the temperature characteristics of power loss in Example 1. FIG. 3 is a graph showing the temperature characteristics of magnetic permeability of the same Example 1. Figure 4 shows Example 1 with 2co30, 03wt%
It is a pattern photograph taken by an optical microscope in the case of addition. FIG. 5 is a pattern photograph taken with an optical microscope in the case of Example 1 with addition of 2CO30.06 wt%. FIG. 6 is a photograph taken with an optical microscope of Example 1 in which 10 wt % of 2CO30 was added. Figure 1 i+ Kuzu 2 Figure Temperature, ljj (''C) Engraving of the drawing (no change in content) Figure 3 Temperature JiC) Engraving of the drawing (no change in content) Figure 4 2CO30.03wt% (magnification X340) Engraving of drawings (no change in content) K2CO30,06wt% (magnification X340) Engraving of drawings (no change in content) K2CO30,10wt% (magnification X340) Procedural amendment (release) 7, December 1989 2O 1. Indication of the case Patent Application No. 163248 filed in 1982 2. Name of the invention Manganese-zinc ferrite material and magnetic core for high-frequency power transformer 3. Person making the amendment Relationship to the case Patent applicant's office
Nihonbashi-chome 13-1, Chuo-ku, Tokyo Name
(306) TDC Co., Ltd. Representative Dai
Kan Toshi 4, Agent 101 Address 4th floor 6, Chiyoda Iwamoto Building, 3-2-2 Iwaki-cho, Chiyoda-ku, Tokyo, ``Brief explanation of drawings'' column of the specification subject to amendment and ``14'' of the drawing.
3 to 6 Details of the amendment ■) The description of ``Brief explanation of the drawings'' on pages 22 to 23 of the specification is amended as follows. 4. Brief Description of the Drawings FIG. 1 is a graph showing the relationship between the power loss at 50°C of the ferrite of Example 1 and the amount of 2CO3 added. FIG. 2 is a graph showing the temperature characteristics of power loss in Example 1. FIG. 3 is a graph showing the temperature characteristics of magnetic permeability of the same Example 1. Figure WIJ4 is a photograph substituted for a drawing showing the structure of the particles, and is an optical micrograph of Example 1 in which 0.03 wt% of 2CO3 was added. FIG. 5 is a photograph substituted for a drawing showing the structure of particles, and is an optical microscope photograph of Example 1 in which 2CO30.06 wt% was added. FIG. 6 is a photograph substituted for a drawing showing the structure of particles, and is an optical micrograph of Example 1 in which 0.10 wt % of 2CO3 was added. 1 (2) Drawing r Figure 3 1 to ``Correct Figure 6 1 as per paper 111. = 39

Claims (7)

[Claims] (1) A manganese-zinc-based ferrite material containing calcium oxide, silicon oxide, niobium oxide, bismuth oxide and/or indium oxide, and potassium oxide. (2) Calcium oxide content is 0 in terms of CaCO_3
．． 03~0.2wt%, silicon oxide content is SiO_
The content of niobium oxide is 0.001 to 0.05 wt% in terms of Nb_2O_5.
, the content of bismuth oxide and/or indium oxide is 0 in terms of Bi_2O_3 and/or In_2O_3
．． 001~0.1wt%, potassium oxide content is K_
The manganese-zinc ferrite material according to claim 1, which has a content of 0.3 wt% or less in terms of 2CO_3. (3) Potassium oxide content is 0 in terms of K_2CO_3
．． 03 to 0.2 wt% of the manganese-zinc ferrite material according to claim 1 or 2. (4) A magnetic core for a high frequency power transformer, characterized by being made of a manganese-zinc ferrite material containing calcium oxide, silicon oxide, niobium oxide, bismuth oxide and/or indium oxide, and potassium oxide. (5) Calcium oxide content is 0 in terms of CaCO_3
．． 03~0.2wt%, silicon oxide content is SiO_
0.05wt% or less when converted to 2, the content of niobium oxide is N
The content of bismuth oxide and/or indium oxide is 0.1 wt% or less in terms of b_2O_5, Bi_2O_3
and/or 0.001 to 0.0 in terms of In_2O_3.
The magnetic core for a high frequency power transformer according to claim 4, wherein the content of potassium oxide is 0.3 wt% or less in terms of K_2CO_3. (6) Potassium oxide content is 0 in terms of K_2CO_3
．． 03 to 0.2 wt% of the magnetic core for a high frequency power lance according to claim 4 or 5. (7) The magnetic core for a high frequency power transformer according to any one of claims 4 to 6, which has an operating frequency of 10 to 100 KHz.