JP3554983B2 - Low-loss oxide magnetic material - Google Patents

Description

【００１０】
表１から，二酸化ハフニウム（ＨｆＯ_２ ）五酸化ニオブ（Ｎｂ_２ Ｏ_５ ），五酸化バナジウム（Ｖ_２ Ｏ_５ ）の複合添加によって電力損失は従来材（Ｎｏ．１）に比べて低い値を示し，最適複合添加量（Ｎｏ．７）においては，従来材に対し約６０％電力損失を低減可能であることが判明した。また，酸化ハフニウム（ＨｆＯ_２ ）１．１０重量％添加試料（Ｎｏ．８），五酸化ニオブ（Ｎｂ_２ Ｏ_５ ）０．４０重量％添加試料（Ｎｏ．９），五酸化バナジウム（Ｖ_２ Ｏ_５ ）０．４０重量％添加試料（Ｎｏ．１０）においては結晶粒に異常粒成長が認められ，比抵抗ρも劣化し電力損失の値が大きくなっている。
【００１１】
また，下記の表２には，実施例における試料番号７と従来材（試料番号１）について，初透磁率μ_ｉ ，飽和磁束密度Ｂ_１５，残留磁束密度Ｂ_ｒ ，保持力Ｈ_ｃ ，比抵抗ρの値を示す。本発明の実施例により材料の比抵抗は従来材の約２０倍と高い値となっている。
【００１２】
【表２】

【００１３】
【発明の効果】
以上の説明で明らかな様に，本発明では，酸化物磁性材料に酸化ハフニウム（ＨｆＯ_２ ），五酸化ニオブ（Ｎｂ_２ Ｏ_５ ），及び五酸化バナジウム（Ｖ_２ Ｏ_５ ）を適量複合添加することにより，スイッチング電源用材料として求められる諸特性を十分に満足するとともに，周波数１ＭＨｚ の高周波において，従来のものより電力の損失を低減できる低損失酸化物磁性材料を提供でき，高周波磁芯用材料として好適であり，変圧器の小型化−軽量化を図ることができる。[0001]
[Industrial applications]
The present invention relates to a low-loss oxide magnetic material, in particular, contains manganese monoxide (MnO), zinc oxide (ZnO) and ferric oxide (Fe ₂ O ₃ ) as main components, and calcium oxide (Fe) as a subcomponent. The present invention relates to an improvement in a low-loss oxide magnetic material containing CaO) and silicon oxide (SiO ₂ ).
[0002]
[Prior art]
Conventionally, a transformer for a switching power supply has a switching frequency of about 50 to 200 kHz exclusively. As a low-loss oxide magnetic material corresponding to this, 30 to 40 mol% as a main component is used. It contains manganese oxide (MnO), 5 to 15 mol% of zinc oxide (ZnO), and ferric oxide (Fe ₂ O ₃ ) as a balance, and 0.02 to 0.5% by weight of calcium oxide ( CaO) and 0.005 to 0.100 those containing by weight% of silicon oxide (SiO ₂₎ have already been developed.
[0003]
[Problems to be solved by the invention]
Switching power supplies have been required to have higher switching frequencies and lower losses in the MHz band due to the demand for smaller and lighter devices. However, when a low-loss oxide magnetic material having a conventional component is used as a magnetic core material of a power transformer using a switching frequency in the MHz band, there is a disadvantage that iron loss is large and heat is generated.
[0004]
Accordingly, an object of the present invention is to provide an oxide magnetic material that can reduce iron loss even when used at a switching frequency in the MHz band.
[0005]
[Means for Solving the Problems]
The present invention contains 30 to 40 mol% of manganese monoxide (MnO) as a main component, 5 to 15 mol% of zinc oxide (ZnO), and the balance of ferric oxide (Fe ₂ O ₃ ). the oxide magnetic material containing .02～0.15 wt% of calcium oxide (CaO) and 0.005 to 0.100 wt% of silicon oxide (SiO _2), as an additive 1.00 wt% or less (0 % Of hafnium dioxide (HfO ₂ ), not more than 0.30% by weight (not including 0% by weight) of niobium pentoxide (Nb ₂ O ₅ ) and not more than 0.30% by weight (0% by weight). (Not including) vanadium pentoxide (V ₂ O ₅ ) at the same time. Here, in the present invention, hafnium dioxide (HfO ₂ ) of 1.00% by weight or less (excluding 0% by weight) and niobium pentoxide of 0.30% by weight or less (excluding 0% by weight) are used as additives. (Nb ₂ O ₅ ) and the addition of vanadium pentoxide (V ₂ O ₅ ) of not more than 0.30% by weight (excluding 0% by weight) were limited to the simultaneous addition. Is observed, the specific resistance is degraded, and the value of the power loss is increased.
[0006]
[Action]
The low-loss oxide magnetic material of the present invention contains manganese monoxide (MnO), zinc oxide (ZnO), and ferric oxide (Fe ₇ O ₃ ) as main components, and calcium oxide (CaO) as a main component. And a sub-component of silicon oxide (SiO ₂ ) and an additive of hafnium dioxide (HfO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), and vanadium pentoxide (V ₂ O ₅ ) in an appropriate amount. Each of the subcomponents and additives precipitate at the crystal grain boundaries, thereby significantly increasing the specific resistance of the grain boundaries, greatly reducing the eddy current loss, and realizing a sufficiently low loss characteristic especially in the frequency range in the MHz band. In the low-loss oxide magnetic material of the present invention, the iron loss can be set to be lowest in a temperature range from room temperature to about 100 ° C., and the iron loss when actually used as a magnetic core for a high-frequency power supply is reduced. Can be reduced.
[0007]
【Example】
Hereinafter, embodiments of the present invention will be described.
[0008]
53.0 mol% of ferric oxide (Fe ₂ O ₃ ), 39.0 mol% of manganese monoxide (MnO), and 8.0 mol% of zinc oxide (ZnO) as main components; Contains 0.030% by weight of silicon dioxide (SiO ₂ ) and 0.100% by weight of calcium oxide (CaO), and further contains hafnium oxide (HfO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), And vanadium pentoxide (V ₂ O ₅ ) were added, mixed and granulated, and pressed after molding. After that, an oxygen concentration in a nitrogen gas atmosphere of 5.0 vol% and a sintering temperature of 1100 to 1300 ° C. were optimal. Sintering was performed at a temperature to obtain an oxide magnetic material. The amounts of the respective subcomponents and additives of the oxide magnetic material and the values of power loss (iron loss) at a frequency of 1 MHz, a magnetic flux density of 500 Gauss (G), and a temperature of 80 ° C. are shown in Table 1 below.
[0009]
[Table 1]

[0010]
From Table 1, the power loss is lower than that of the conventional material (No. 1) due to the composite addition of hafnium dioxide (HfO ₂ ) niobium pentoxide (Nb ₂ O ₅ ) and vanadium pentoxide (V ₂ O ₅ ). It was found that the optimum composite addition amount (No. 7) could reduce the power loss by about 60% compared to the conventional material. Also, a sample (No. 8) containing 1.10% by weight of hafnium oxide (HfO ₂ ), a sample (No. 9) containing 0.40% by weight of niobium pentoxide (Nb ₂ O ₅ ), and vanadium pentoxide (V ₂ O) ₅ ) In the sample (No. 10) added with 0.40% by weight, abnormal grain growth was observed in the crystal grains, the specific resistance ρ was also deteriorated, and the value of the power loss was large.
[0011]
In Table 2 below, the initial magnetic permeability μ _i , the saturation magnetic flux density B ₁₅ , the residual magnetic flux density B _r , the coercive force H _c , and the specific resistance of the sample No. 7 in the embodiment and the conventional material (sample No. 1) are shown. Indicates the value of ρ. According to the embodiment of the present invention, the specific resistance of the material is as high as about 20 times that of the conventional material.
[0012]
[Table 2]

[0013]
【The invention's effect】
As is apparent from the above description, in the present invention, an appropriate amount of hafnium oxide (HfO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), and vanadium pentoxide (V ₂ O ₅ ) are added to the oxide magnetic material in an appropriate amount. As a result, it is possible to provide a low-loss oxide magnetic material that satisfies various characteristics required as a material for a switching power supply and that can reduce power loss at a high frequency of 1 MHz as compared with a conventional material. Therefore, the size and weight of the transformer can be reduced.

Claims (1)

Comprises 30 to 40 mole% of the manganese monoxide (MnO), 5 to 15 mol% of zinc oxide (ZnO) and the remaining portion ferric oxide _(Fe 2 _{O 3)} as a main component, 0.02 to 0 as the minor component the oxide magnetic material containing .15 weight percent calcium oxide (CaO) and 0.005 to 0.100 wt% of silicon oxide (SiO _2), 1.00 wt% or less as an additive (excluding 0 wt% Hafnium dioxide (HfO ₂ ), niobium pentoxide (Nb ₂ O ₅ ) of not more than 0.30% by weight (excluding 0% by weight) and not more than 0.30% by weight (not including 0% by weight). A low-loss oxide magnetic material to which vanadium pentoxide (V ₂ O ₅ ) is simultaneously added.