JP2855275B2 - Low loss oxide magnetic material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a low-loss oxide magnetic material, in particular, 30 to 40 mol% of manganese oxide (MnO), 5 to 15 mol% of zinc oxide (ZnO) as a main component, and Ferric oxide (Fe ₂
O ₃₎ comprises a 0.02 to 0.15 wt% of calcium oxide as a secondary component (CaO), 0.005 to 0.100 wt% of silicon oxide (S
The present invention relates to the improvement of low-loss oxide magnetic materials containing iO ₂ ).

[Conventional technology]

Conventionally, manganese-zinc-based ferrite has been widely used as a transformer material for various communication devices, consumer devices, etc., but in a transformer for a switching power supply, it is used exclusively at a switching frequency of about 10 to 100 kHz, As the low-loss oxide magnetic material to cope with this, those having the above-mentioned components have been used.

[Problems to be Solved by the Invention] In recent years, low-loss oxide magnetic materials tend to use switching frequencies of 100 kHz or higher in order to reduce the size and weight of switching power supplies. Performance is required.

On the other hand, when a low-loss oxide magnetic material having a conventional component is used as a core material of a transformer for a switching power supply having a switching frequency of 100 kHz or more, there is a disadvantage that the iron loss is large and heat is generated.

Therefore, a technical problem of the present invention is to provide a low-loss oxide magnetic material having a small iron loss even when used at a high frequency of 100 kHz or more.

B. Constitution of the Invention [Means for Solving the Problems] In order to solve the above problems, the present inventors have made the above-mentioned 30 to 40 mol% manganese oxide (MnO) as a main component, 5 to 15 mol%.
Includes mol% of zinc oxide (ZnO), and ferric oxide as residue (Fe ₂ O _3), and 0.02 to 0.15 wt% of calcium oxide as a secondary component (CaO), 0.005 to 0.100 wt% of silicon oxide In low-loss oxide magnetic materials containing (SiO ₂ ),
30% by weight or less (excluding 0%) of zirconium oxide (Zr
O ₂ ), 0.50% by weight or less (excluding 0%) of aluminum oxide (Al ₂ O ₃ ), and 0.20% by weight or less (excluding 0%) of vanadium oxide (V ₂ V ₅ ) were added. We have found that low-loss oxide magnetic materials can be used as low-loss cores in transformers for switching power supplies with switching frequencies higher than 100 kHz.

That is, the present invention contains 30 to 40 mol% of manganese oxide (MnO), 5 to 15 mol% of zinc oxide (ZnO) as a main component, and ferric oxide (Fe ₂ O ₃ ) as a balance. As an ingredient,
0.02 to 0.15% by weight of calcium oxide (CaO) and 0.005 to 0.100% by weight of silicon oxide (SiO ₂ ) based on the total amount of main components
% Of zirconium oxide (ZrO ₂ ) or less than 0.50% by weight (excluding 0%) of aluminum oxide of 0.30% by weight or less (excluding 0%) of the total main components A low-loss oxide magnetic material characterized by adding (Al ₂ O ₃ ) and 0.20% by weight or less (excluding 0%) of vanadium oxide (V ₂ O ₅ ).

Action Zirconium oxide (ZrO ₂ ), Aluminum oxide (Al ₂ O
₃ ) and vanadium oxide (V ₂ O ₅ ) were added in combination, and these combined effects reduced iron loss in the switching frequency band of 100 kHz or more.

The additives ZrO ₂ and V ₂ O ₅ precipitate at the grain boundaries and increase the grain boundary resistance, and the additive Al ₂ O ₃ forms a solid solution in the crystal and increases the internal resistance of the crystal, Al ₂ O ₃ has the function of making the grain structure uniform, and it is considered that each effect contributes in a complex manner.

〔Example〕

 Hereinafter, embodiments of the present invention will be described.

As Examples and Comparative Examples of the present invention, the main components contained 53.0 mol% of ferric oxide (Fe ₂ O ₃ ), 36.0 mol% of manganese oxide (MnO), and 11.0 mol% of zinc oxide (ZnO). And silicon oxide (SiO ₂ ) and calcium oxide (CaO) as subcomponents, and zirconium oxide (Zr
O ₂ ), aluminum oxide (Al ₂ O ₃ ), vanadium oxide (V
₂ O ₅ ) is used alone or in combination with oxide magnetic materials. These materials have a frequency of 200 kHz and a maximum magnetic flux density Bm of 10
Table 1 shows the minimum value of the power loss in the case of 00G in comparison with the additive amount of the subcomponent.

In addition, for one embodiment of the present invention (Sample No. 8 in Table 1) and a comparative example of the conventional composition (Sample No. 1 in Table 1), initial magnetic permeability μ, saturation magnetic flux density B ₁₅ , residual magnetic flux density Br , Specific resistance ρ
Table 2 shows a comparison of the values.

The low-loss oxide magnetic materials of the examples and comparative examples of the present invention were composed of 53.0 mol% of ferric oxide (Fe ₂ O ₃ )
6.0 mol% of manganese oxide (MnO) and 11.0 mol% of zinc oxide (ZnO) have silicon oxide (SiO ₂ ), calcium oxide (CaO), zirconium oxide (ZrO ₂ ), and aluminum oxide (Al ₂ O) as subcomponents. ₃ ) Vanadium oxide (V ₂ O ₅ ) alone or in combination with raw materials mixed and added, granulated, pressed after molding, and then subjected to an oxygen partial pressure of 5.0 atm in a nitrogen gas atmosphere.
% Or less at a temperature of 1300 to 1400 ° C. Table 1 shows the samples of each material prepared by the method described above.
The relationship between the added amount of each subcomponent and the power loss at 200 kHz is shown.

From the results in Table 1, it can be seen that Samples Nos. 8, 9, and 1
0,12,13,14,16,17,19,20 are zirconium oxide (ZrO ₂ ),
Aluminum oxide (Al ₂ O ₃ ), vanadium oxide (V ₂ O ₅ )
It can be seen that the power loss characteristics are improved by the composite addition of. Sample No. 11 containing 0.4% by weight of zirconium oxide (ZrO ₂ ) of the comparative example, aluminum oxide (Al ₂ O ₃ )
Sample No.15, vanadium oxide (V
₂ O ₅₎ for 0.3 wt% sample No.18 was added observed growth of abnormal grain, large power loss in Table 1, it can be seen that improvement is small.

Comparing the electromagnetic characteristics of Sample No. 8 of the example of the present invention in Table 2 with Sample No. 1 of the comparative example of the conventional composition, the magnetic characteristics are almost the same. Is about 10 times or more, and it can be understood that high magnetic characteristics are maintained and good low loss characteristics are shown in a high frequency region. In the present embodiment, one basic composition point has been described, but similar results can be obtained in other basic composition points in the claims.

C. Effects of the Invention [Effects of the Invention] As can be seen from the above description, according to the present invention, zirconium oxide (ZrO ₂ ), aluminum oxide (Al ₂ O ₃ ), and vanadium oxide (V ₂ O ₅ ) are used as additives. The composite addition sufficiently satisfies various characteristics required as a core material for a switching power supply, and can provide a low-loss oxide magnetic material with significantly reduced power loss even at a frequency of 100 kHz or more.

Claims (1)

(57) [Claims] 1. A composition comprising, as main components, 30 to 40 mol% of manganese oxide (MnO), 5 to 15 mol% of zinc oxide (ZnO) and, as a balance, ferric oxide (Fe ₂ O ₃ ); As sub-components, 0.02-0.15% by weight of calcium oxide (CaO) and 0.005-0.100% by weight of silicon oxide (SiO ₂ ) based on the total amount of the main components
% Of zirconium oxide (ZrO ₂ ) or less than 0.50% by weight (excluding 0%) of aluminum oxide of 0.30% by weight or less (excluding 0%) of the total main components A low-loss oxide magnetic material comprising (Al ₂ O ₃ ) and 0.20% by weight or less (excluding 0%) of vanadium oxide (V ₂ O ₅ ).