JPS61252609A - Magnetic material of low-loss oxide - Google Patents

Abstract

PURPOSE:To obtain a magnetic material which assures low iron loss even in use at a frequency higher than 200kHz by adding the specified amount of SnO2 to a material including the specified amounts of MnO, ZnO, Fe2O3, CaO and SiO2. CONSTITUTION:SnO2 at 0.50-0.90wt% is added to the low-loss oxide magnetic material including, as the main elements, MnO of 30-37mol%, ZnO of 10-15mol% and Fe2O3 (remainder) and also including, as the sub-material, CaO of 0.04-0.10wt% and SiO2 of 0.015-0.100wt%. Thereby, a low-loss oxide magnetic material which sufficiently satisfies various characteristics required for switching power supply material and realizes power loss lower than that of the existing material at a frequency higher than 200kHz can be provided. This material is just suited for magnetic core material for high frequency and realizes reduction in size and light weight of transformer.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to low loss oxide magnetic materials, and more particularly.

The main component is 30 to 37 molt manganese monoxide (Mn).
O), containing 10 to 15 moles of zinc oxide (ZnO) and the balance ferric oxide (Fe12O3), and 0.04 to 0.10% by weight of calcium oxide (Cab) as an accessory component.
) and 0.015 to 0.100% by weight of silicon dioxide (S
This invention relates to improvements in low-loss oxide magnetic materials including 102).

[Conventional technology]

Conventionally, in transformers for switching power supplies.

A switching frequency of approximately 100 kHz is used, and low-loss oxide magnetic materials having the above-mentioned components have already been developed to accommodate this.

[Problem that the invention seeks to solve]

In recent years, in order to make switching power supplies smaller and lighter, there has been an increasing demand for them to be used at high switching frequencies of 200 kHz or higher. However.

When a low-loss oxide magnetic material having conventional components is used as a core material of a transformer for a switching power supply with a switching frequency of 200 kHz or more, there is a drawback that the core loss is large and heat is generated.

Therefore, one object of the present invention is to reduce the zero frequency to 200 kHz [
Means for Solving the Problems] The present invention uses 30 to 37 mol of manganese (MnO) and 10 to 15 mol of zinc (ZnO) as main components.
O) and the balance ferric oxide (Fe2O3), and 0.04 to 0.10% by weight of calcium oxide (C
aO) and 0.015 to 0.100% by weight of silicon dioxide (SiO2),
0.50-0.90% by weight of stannic oxide (SnO2)
It is characterized by the addition of.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 shows 52.5 mol of ferric oxide (F) as the main component.
e2O3), 34.0 molar manganese monoxide (Mn
ZnO) and 13.5 mol of zinc oxide (ZnO), and 0.018% by weight of silicon dioxide (Si) as an accessory component.
O2) and 0.045% by weight calcium oxide (CaO)
containing stannic oxide (,5n02-
, ) were added, mixed, granulated, molded and pressed, and then sintered at an oxygen partial pressure of 0.8 at% and a temperature of 1270°C to obtain an oxide magnetic material. FIG. 2 is a diagram showing the relationship between power loss 'P'B [kW/m3] and temperature T [°C] when the amount of ditin (5n02,) added is used as a parameter.

Here, FIG. 1 shows the power loss when the two frequencies are 2O'OkHz and the maximum magnetic flux density Bm is 2000G. In addition, in FIG. 1, 1 is stannic oxide (5n02
) is not added, 2 is when 0.50% by weight of stannic acid (5N02) is added, and 3 is when 0.75% by weight of stannic oxide (SnO2) is added.

4 is when 0.90% by weight of stannic oxide (SnO2) is added, and 5 is when 1.00% by weight of stannic oxide (SnO2) is added.
The characteristics when 2) is added are shown.

As shown in Figure 1, when the frequency is 200 kHz, the temperature T at which the power loss pB reaches the minimum value when stannic oxide (5 nOz) is not added is about 60°C, whereas when the stannic oxide (5 nOz) It can be seen that as the amount of addition increases, the temperature at which the power loss pB is the minimum value shifts to the lower temperature side. Further, the amount of stannic oxide (SnO2) added is about 0.
It can also be seen that when the addition amount is 75% by weight, the power loss pB is smaller in most temperature ranges than in the case of other addition amounts (including 0 yen). Added amount of stannic oxide (5nO2) is 0
．． If the amount is smaller than 50% by weight, the staining force loss pB will be greater than that without addition.

Furthermore, when the amount of stannic oxide (5n02) added exceeds 0.90% by weight, the power loss pB tends to be larger than that without addition. This thing is 99 frequency 2O0kHz
In, 0.05 to 0.90% by weight of stannic oxide
It can be seen that when added, the power loss is smaller than when not added, especially on the low temperature side.

Figure 2 shows two oxide magnetic materials AI (
0.018% by weight of silicon dioxide (SiO
2) -0,045% by weight of calcium oxide (CaO)
and 0.75% by weight of stannic oxide (SnO2)), and the conventional oxide magnetic material l62 (containing 0.75% by weight of stannic oxide (SnO2)).
0.018 wt% silicon dioxide (SiO2) and 0.045
% by weight of calcium oxide (CaO) and no added stannic oxide (5n02)) and A3 (0.010% by weight of silicon dioxide (5i02) as accessory components).
．． Contains 030% by weight of calcium oxide (Cab),
Properties of (without adding stannic oxide (5n02))
Initial magnetic permeability μi, saturation magnetic flux density B86 (magnetic flux density at magnetizing force 150e) CG), residual magnetic flux density Br [G], coercive force He (Oe], and specific resistance ρ [Ω·return]) are shown. The main component in both cases is ferric oxide (ve2os).
It contains 2.5 mol %, 34.0 mol % of manganese oxide (MnO) and 13.5 mol % of zinc oxide (ZnO).

As is clear from FIG.

Characteristics required for magnetic core materials for switching power supplies 1
For example, the initial magnetic permeability μi is about 2500. Saturation magnetic flux density B15
satisfies the characteristics of approximately 5000G and residual magnetic flux density Br of 1000G or less, and the specific resistance ρ is also lower than that of the conventional A2
This is a significant improvement compared to 3.

From the above, the additive tin oxide (Sn02) is
It sufficiently satisfies various properties required as a magnetic core material for switching power supplies, and also reduces power loss P B (kW/m3) at high frequencies of 2O0kHz or higher.For example, about 0.75% by weight of tin oxide (SnO2 ) is added, the temperature side is particularly lower (
For example, it can be seen that an improvement of about 25% can be achieved at temperatures below 60°C.

〔Effect of the invention〕

As is clear from the above explanation, by adding 0.50-0.90% by weight of stannic oxide (SnO2),
It is possible to provide a low-loss oxide magnetic material that fully satisfies various characteristics required as a material for a switching power supply and can reduce stain force loss compared to conventional materials at high frequencies of 200 kHz or higher.

Suitable as a magnetic core material for high frequency, miniaturization of transformers.
Weight reduction can be measured.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between temperature and power loss when the amount of stannic oxide (5n02) added is used as the main meter.
FIG. 2 is a diagram showing various characteristics of the present invention and conventional oxide magnetic materials. Figure 1 TEMP('C)

Claims (1)

[Claims] 1. 30 to 37 mol% manganese monoxide as the main component (
MnO), 10-15 mol% zinc oxide (ZnO) and the balance ferric oxide (Fe_2O_3), and 0.04-0.10 wt% calcium oxide (CaO) as an accessory component.
) and 0.015 to 0.100% by weight of silicon dioxide (S
iO_2) in a low-loss oxide magnetic material containing 0.
A low-loss oxide magnetic material characterized by adding 50 to 0.90% by weight of stannic oxide (SnO_2).