JP2620959B2 - Low loss oxide magnetic material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-loss oxide magnetic material comprising a Mn-Zn ferrite suitable for use in a power supply core such as a display monitor.

[Prior Art] Conventionally, as this type of ferrite for power supply, there is a Mn-Zn ferrite proposed by the present applicant in Japanese Patent Publication No. 53-28634. This Mn-Zn ferrite is composed of CaO, SiO ₂ , Cl and SnF.
_The addition of ₂ is intended to reduce power loss.

[Problems to be solved by the invention]

By the way, in recent years, higher resolution of display monitors and the like,
In response to demands for larger screens and the like for consumer color televisions, power supplies used for these devices have been operating at higher frequencies and have been increasingly loaded.

However, in the conventional Mn-Zn ferrite, the power loss increases, the temperature of the power supply rises remarkably, and the reliability decreases.

The present invention solves the above-mentioned problems by providing a low-loss Mn-Zn with significantly improved power loss even at high frequencies and high loads.
An object of the present invention is to provide a low-loss oxide magnetic material comprising a system ferrite.

[Means for solving the problem]

 The present invention is the following low-loss oxide magnetic material.

_{(1) Fe 2 O 3 52~56mol} %, MnO32~42mol% and ZnO5~
15 mol% as main component, Al10 ~ 130ppm, SiO2 ₂₀₀ ~ 300ppm
And a low-loss oxide magnetic material simultaneously containing 500 to 2000 ppm of CaO as an auxiliary component.

_{(2) Fe 2 O 3 52~56mol} %, MnO32~42mol% and ZnO5~
15mol% as main component, Cr 10-100ppm, SiO ₂ 200-300ppm
And a low-loss oxide magnetic material simultaneously containing 500 to 2000 ppm of CaO as an auxiliary component.

In the method for producing a low-loss oxide magnetic material of the present invention, a raw material of a main component is mixed and calcined, and a raw material of an auxiliary component is added to a ferrite powder obtained by pulverization and mixed, and polyvinyl alcohol or the like is mixed. And then granulating, molding and sintering. As each of the above-mentioned raw materials, in addition to the respective oxides, salts and other compounds which become the above-mentioned oxides by sintering can be used.

[Action]

The low-loss oxide magnetic material for Mn-Zn ferrite of the invention, the main component Fe ₂ O _3, MnO and ZnO, Al10～130ppm or Cr10~100ppm as subcomponent, SiO ₂ 200-300 ppm
And 500 to 2,000 ppm of CaO are added in a weight ratio, and the power loss can be remarkably reduced, and a sufficiently low loss characteristic can be realized even in a frequency region of about 130 kHz.
When used in a transformer core, heat is generated during operation. However, the low-loss ferrite of the present invention can be set so that power loss is minimized in a temperature range of about 60 ° C. to 100 ° C. Therefore, power loss during operation can be reduced.

(Example of the invention)

 Hereinafter, examples of the present invention will be described.

Example 1 After calcining a raw material mainly containing 53.5 mol% of Fe ₂ O _3, 38.5 mol% of MnO and 8.0 mol% of ZnO, a ferrite powder obtained by finely pulverizing was added with 94 ppm of Al ₂ O ₃ as an auxiliary component. (50pp as Al
m), 1000PP the SiO ₂ 200 ppm, the CaCO ₃ as 1640ppm (CaO
After adding and mixing at a ratio of m), a polyvinyl alcohol solution was added as a binder, and the mixture was granulated, and molded into a ring-shaped sample having an outer diameter of 60 mm, an inner diameter of 40 mm, and a height of 10 mm at a molding pressure of 1 ton / cm ² . However, as for these additives, those contained in the raw material were analyzed in advance, and the added amount was reduced by that amount, and adjusted so as to have the above value as a whole. The oxygen concentration of this sample was controlled.
The main firing was performed at 1350 ° C. for 2 hours in a N ₂ atmosphere furnace.

This sample was subjected to a frequency of 25 kHz, a magnetic flux density of 2000 Gauss, and 100 ° C.
The result of measuring the power loss under the above measurement conditions is 65 mW / cm ³
Met. The waveform at this time is a sine wave. Also 10kHz, 1
The result of measurement of the initial magnetic permeability μi at 0 T and 10 mA was 1880.

Examples 2 to 10 and Comparative Examples 1 to 5 The main components were the same as in Example 1, and the sample preparation method was the same as that of Example 1 except that the sub-components were changed, and the power loss and μ
Are shown in Table 1. The measurement conditions of the power loss and μi in this table are the same as in the first embodiment.

From the results shown in Table 1, it is clear that by adding Al, SiO ₂ and CaO in combination, power loss is greatly improved and a low-loss oxide magnetic material can be obtained. However, sub-component Al
Is less than 10 ppm and more than 130 ppm, the power loss is undesirably large.

When the content of SiO _{2 as a} sub-component is less than 200 ppm or more than 300 ppm, the electric resistance decreases and the power loss increases, which is inappropriate. If the content of CaO is more than 2000 ppm, the crystal grain size becomes small, but the power loss becomes large because the hysteresis loss increases. If the content of CaO is less than 500 ppm, the crystal grain boundary layer becomes thin, and eddy current loss increases. In addition, as long as the above components in the present invention are contained before the main firing, the addition thereof may be performed in any step.

Example 11 to 20, the same Comparative Example 6-10 Example 1 and the main component, the method of sample preparation is also the same procedure, the sub-components using the Cr ₂ O ₃ instead of Al ₂ O ₃ subcomponents Table 2 shows the results of measuring the power loss and μi by changing the amount of The measurement conditions of the power loss and μi in this table are the same as in the first embodiment.

From the results in Table 2, it is clear that the composite loss of Cr, SiO ₂ and CaO significantly reduces the power loss and provides a low-loss oxide magnetic material. However,
When Cr is less than 10 ppm, the crystal grain size is small and 1
If it is more than 00 ppm, it becomes large, and both power loss becomes large, which is inappropriate.

When the content of SiO _{2 as a} sub-component is less than 200 ppm or more than 300 ppm, the electric resistance decreases and the power loss increases, which is inappropriate. If the content of CaO is more than 2000 ppm, the crystal grain size becomes small, but the power loss becomes large because the hysteresis loss increases. If the content of CaO is less than 500 ppm, the crystal grain boundary layer becomes thin, and eddy current loss increases. In addition, as long as the above components in the present invention are contained before the main firing, the addition thereof may be performed in any step.

〔The invention's effect〕

As described above, according to the present invention, Fe ₂ O ₃ , MnO and
ZnO as a main component, Al10-130ppm as a subcomponent, or C
r10~100ppm, SiO ₂ 200~300ppm and CaO500~2000ppm
Can be significantly reduced by using a composition in which is added as a composite. For this reason, it is possible to contribute to the efficiency and miniaturization of the power supply of a high-frequency display monitor, a large-screen color television, and the like, which is extremely useful in industry.

Claims (2)

(57) [Claims] (1) 52 to 56 mol% of Fe ₂ O _3, 32 to 42 mol% of MnO and
A main component ZnO5~15mol%, Al10~130ppm, SiO ₂ 200~
A low-loss oxide magnetic material comprising simultaneously 300 ppm and 500 to 2000 ppm of CaO as accessory components. _2. 52 to 56 mol% of Fe ₂ O _3, 32 to 42 mol% of MnO and
A main component ZnO5~15mol%, Cr10~100ppm, SiO ₂ 200~
A low-loss oxide magnetic material comprising simultaneously 300 ppm and 500 to 2000 ppm of CaO as accessory components.