JP2004022619A - Ferrite for lan card and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxide magnetic material of Mn-Zn family to be used as the core of a transformer for Ethernet LAN cards or the like, which can be used at a bit rate of 100Mbits/s, and furthermore, exhibits excellent characteristics in a wide temperature range of -40 to +85°C. <P>SOLUTION: The oxide magnetic material is composed of, as main components, iron oxide of 53-54mol% as Fe<SB>2</SB>O<SB>3</SB>, manganese oxide of 26-27.5mol% as MnO, and zinc oxide of 19-21mol% as ZnO, and contains, as subcomponents, SiO<SB>2</SB>of 0.01-0.02wt%, CaO of 0.015-0.045wt%, and Nb<SB>2</SB>O<SB>5</SB>of 0.01-0.05wt%. <P>COPYRIGHT: (C)2004,JPO

Description

【００２５】
表１において、試料番号Ｎｏ．１〜３は本発明の実施例を示し、試料番号Ｎｏ．４〜１５は特性比較のための比較例である。
【００２６】
表１より、本発明の実施例では、室温（Ｒ・Ｔ）での１００ｋＨｚの初透磁率が４０００以上であり、−４０℃と８５℃において、Ｈｄｃが１０ＡＴ／ｍの時の実効透磁率が３０００以上、Ｈｄｃが２０ＡＴ／ｍの時の実効透磁率が２５００以上、Ｈｄｃが３０ＡＴ／ｍの時の実効透磁率が２０００以上、Ｈｄｃが４０ＡＴ／ｍの時の実効透磁率が１５００以上というすぐれたものであることがわかる。
【００２７】
Ｆｅ_２Ｏ_３が５３ｍｏｌ％より少ないと、８５℃における３０ＡＴ／ｍ、４０ＡＴ／ｍの時の実効透磁率が２０００、１５００に達せず小さい（試料番号Ｎｏ．９参照）。
【００２８】
Ｆｅ_２Ｏ_３が５４ｍｏｌ％より大きいと、初透磁率が小さく、８５℃における１０ＡＴ／ｍ、３０ＡＴ／ｍ時の実効透磁率が３０００、２０００に達せず小さい（試料番号Ｎｏ．５、Ｎｏ．１３参照）。
【００２９】
ＭｎＯが２６ｍｏｌ％より少ないと、８５℃における３０ＡＴ／ｍ、４０ＡＴ／ｍ時の実効透磁率が２０００、１５００に達せず小さい（試料番号Ｎｏ．７参照）。
【００３０】
ＭｎＯが２７．５ｍｏｌ％より大きいと、８５℃における１０ＡＴ／ｍ時の実効透磁率が３０００に達せず小さい（試料番号Ｎｏ．１３参照）。
【００３１】
ＺｎＯが１９ｍｏｌ％より少ないと、初透磁率が４０００に達せず小さかったり、８５℃における４０ＡＴ／ｍ時の実効透磁率が１５００に達せず小さかったりする（試料番号Ｎｏ．８参照）。
【００３２】
ＺｎＯが２１ｍｏｌ％より大きいと、８５℃における３０ＡＴ／ｍ時の実効透磁率が２０００に達せず小さかったり、４０ＡＴ／ｍ時の実効透磁率が１５００に達せず小さかったりする（試料番号Ｎｏ．９参照）。
【００３３】
特に、Ｆｅ_２Ｏ_３が５３〜５３．５ｍｏｌ％、ＭｎＯが２６〜２６．５ｍｏｌ％、ＺｎＯが１９．５〜２０．５ｍｏｌ％の場合には、表１の試料番号Ｎｏ．１、Ｎｏ．２に示す如く、初透磁率や−４０℃における１０ＡＴ／ｍ、２０ＡＴ／ｍ、３０ＡＴ／ｍ時の実効透磁率が大きく、また８５℃における１０ＡＴ／ｍ、２０ＡＴ／ｍ、３０ＡＴ／ｍ時の実効透磁率がこれまた大きいことがわかる。
【００３４】
また表２にフェライト焼成工程の安定部における酸素分圧の雰囲気を異なる値にした場合の特性を示す。表２は、表１の試料番号Ｎｏ．１の試料即ち、フェライトを主成分としてＦｅ_２Ｏ_３５３．２５ｍｏｌ％、ＭｎＯ２６．５０ｍｏｌ％、ＺｎＯ２０．２５ｍｏｌ％、副成分としてＳｉＯ_２０．０１５ｗｔ％、ＣａＯ０．０４ｗｔ％、Ｎｂ_２Ｏ_５０．０２ｗｔ％で構成したものを使用し、焼成工程の安定部における酸素分圧の雰囲気を５％〜２０％の範囲で５％毎に変化した場合の室温での１００ｋＨｚの初透磁率μｉ、−４０℃と８５℃のＨｄｃが１０、２０、３０、４０ＡＴ／ｍの時の実効透磁率μｅを表２に示す。
【００３５】
【表２】

【００３６】
表２において、試料番号Ｎｏ．１、２は本発明の実施例を示し、試料番号Ｎｏ．３、４は特性比較のための比較例である。
【００３７】
表２より、本発明の実施例である焼成工程の安定部における酸素分圧の雰囲気が１０％以下の５％、１０％である試料番号Ｎｏ．１、２の場合は、前記初透磁率が４０００以上であり、−４０℃〜８５℃の範囲でＨｄｃが１０ＡＴ／ｍの時の実効透磁率が３０００以上、Ｈｄｃが２０ＡＴ／ｍの時の実効透磁率が２５００以上、Ｈｄｃが３０ＡＴ／ｍの時の実効透磁率が２０００以上、Ｈｄｃが４０ＡＴ／ｍの時の実効透磁率が１５００以上というすぐれた特性を示すことがわかる。
【００３８】
しかし比較例である試料番号Ｎｏ．３、４の番号は、−４０℃と８５℃においてＨｄｃが３０ＡＴ／ｍ、４０ＡＴ／ｍ時の実効透磁率が２０００、１５００に達せず小さいことがわかる。
【００３９】
次に副成分について説明する。
【００４０】
まず、基本組成として最終組成がＦｅ_２Ｏ_３：５３．２５ｍｏｌ％、ＭｎＯ：２６．５０ｍｏｌ％、ＺｎＯ：２０．２５ｍｏｌ％となるように出発原料を秤量し、これらを湿式混合した後、スプレードライヤーで乾燥させ、大気中で９００℃で２時間仮焼きした。
【００４１】
それから主成分の原料の仮焼物と、表３に示す数値のｗｔ％の副成分とを混合した（なお１．００ｐｐｍ＝０．０１％である）。
【００４２】
得られた混合物にバインダとしてＰＶＡを加え、スプレードライヤーにて顆粒化した後、この粉末を１ｔｏｎ／ｃｍ^２の圧力にて加圧成形し、トロイダル状の磁心サンプルを得た。
【００４３】
得られたトロイダル状の磁心サンプルを、焼成工程における昇温部の昇温速度は室温〜９００℃が３００℃／Ｈｒ、９００℃〜安定温度が１００℃／Ｈｒで、そのときの雰囲気は窒素雰囲気とした。
【００４４】
また安定温度は１３６０℃、安定部の酸素濃度は５％の条件とした。
【００４５】
そして安定温度から１０００℃までの冷却帯は安定部の酸素分圧以下の酸素分圧で制御を行った。
【００４６】
得られた各トロイダルコアの２５℃における１００ｋＨｚの初透磁率μｉ、及び−４０℃と８５℃のＨｄｃが１０、２０、３０、４０ＡＴ／ｍの時の実効透磁率を測定した。なおこれら初透磁率、実効透磁率の測定にはインピーダンスアナライザーを用いた。
【００４７】
これらの各サンプルについて室温（２５℃）の１００ｋＨｚの初透磁率、−４０℃と８５℃のＨｄｃが１０、２０、３０、４０ＡＴ／ｍの時の実効透磁率を表３に示す。
【００４８】
【表３】

【００４９】
表３において、試料番号Ｎｏ．１〜９は本発明の実施例を示し、試料番号Ｎｏ．１０〜１６は特性比較のための比較例である。
【００５０】
表３より、本発明の実施例では、室温での１００ｋＨｚの初透磁率が４０００以上であり、−４０℃と８５℃において、Ｈｄｃが１０ＡＴ／ｍの時の実効透磁率が３０００以上、Ｈｄｃが２０ＡＴ／ｍの時の実効透磁率が２５００以上、Ｈｄｃが３０ＡＴ／ｍの時の実効透磁率が２０００以上、Ｈｄｃが４０ＡＴ／ｍの時の実効透磁率が１５００以上というすぐれたものであることがわかる。
【００５１】
ＳｉＯ_２が０．０１ｗｔ％より少ないと、８５℃における３０ＡＴ／ｍ、４０ＡＴ／ｍの実効透磁率が２０００、１５００に達せず小さい（試料番号Ｎｏ．１０参照）。
【００５２】
ＳｉＯ_２が０．０２ｗｔ％より大きいと、初透磁率が４０００に達せず、また−４０℃におけるＨｄｃが１０ＡＴ／ｍ、３０ＡＴ／ｍの時の実効透磁率が３０００、２０００に達せず小さい（試料番号Ｎｏ．１６参照）。
【００５３】
ＣａＯが０．０１５ｗｔ％より少ないと８５℃におけるＨｄｃが３０ＡＴ／ｍ、４０ＡＴ／ｍの時の実効透磁率が２０００、１５００に達せず小さい（試料番号Ｎｏ．１７参照）。
【００５４】
ＣａＯが０．０４５ｗｔ％より大きいと、−４０℃におけるＨｄｃが１０ＡＴ／ｍ、２０ＡＴ／ｍの時の実効透磁率が３０００、２５００に達せず、また８５℃におけるＨｄｃが４０ＡＴ／ｍの時の実効透磁率が１５００に達せず小さい（試料番号Ｎｏ．１３参照）。
【００５５】
Ｎｂ_２Ｏ_５が０．０１ｗｔ％より小さいと、−４０℃におけるＨｄｃが４０ＡＴ／ｍの時の実効透磁率が１５００に達せず、また８５℃におけるＨｄｃが３０ＡＴ／ｍ、４０ＡＴ／ｍの時の実効透磁率が２０００、１５００に達せず小さい（試料番号Ｎｏ．１４参照）。
【００５６】
Ｎｂ_２Ｏ_５が０．０５ｗｔ％より大きいと、初透磁率が４０００に達せず、−４０℃におけるＨｄｃが１０ＡＴ／ｍ、２０ＡＴ／ｍの時の実効透磁率が３０００、２５００に達せず小さい（試料番号Ｎｏ．１５参照）。
【００５７】
特にＳｉＯ_２を０．０１〜０．０１５ｗｔ％、ＣａＯを０．０３〜０．０４ｗｔ％、Ｎｂ_２Ｏ_５を０．０２〜０．０４ｗｔ％含有する場合は、表３の試料番号Ｎｏ．１、Ｎｏ．６〜８に示す如く、−４０℃、８５℃におけるＨｄｃ２０ＡＴ／ｍ、３０ＡＴ／ｍの時の実効透磁率が大きくすぐれていることがわかる。このＨｄｃ２０ＡＴ／ｍ、３０ＡＴ／ｍは利用頻度の比較的大きな範囲である。
【００５８】
本発明のフェライトコアにおける実質的な主成分は、酸化鉄をＦｅ_２Ｏ_３換算で５３〜５４ｍｏｌ％、酸化マンガンをＭｎＯ換算で２６〜２７．５ｍｏｌ％、酸化亜鉛をＺｎＯ換算で１９〜２１ｍｏｌ％で構成され、酸化鉄をＦｅ_２Ｏ_３換算で５３〜５３．５ｍｏｌ％、酸化マンガンをＭｎＯ換算で２６〜２６．５ｍｏｌ％、酸化亜鉛をＺｎＯ換算で１９．５〜２０．５ｍｏｌ％で構成されることがより好ましい。
【００５９】
Ｍｎ−Ｚｎ系フェライトでは、初透磁率の温度依存性曲線が２つのピークを持つものとなる。初透磁率が相対的に高いピークをプライマリーピークとし、相対的に低いピークをセカンダリーピークとしたとき、プライマリーピークは高温側に存在し、セカンダリーピークは低温側に存在する。主成分の組成比が上記範囲を外れると、セカンダリーピーク及びプライマリーピークが低温方向または高温方向に移動してしまい、−４０℃あるいは８５℃での良好な特性を得ることができなくなる。
【００６０】
また本発明では上記主成分に対して副成分をＳｉＯ_２換算で０．０１〜０．０２ｗｔ％、ＣａＯ換算で０．０１５〜０．０４５ｗｔ％、Ｎｂ_２Ｏ_５換算で０．０１〜０．０５ｗｔ％含有していることが好ましく、ＳｉＯ_２換算で０．０１〜０．０１５ｗｔ％、ＣａＯ換算で０．０３〜０．０４ｗｔ％、Ｎｂ_２Ｏ_５換算で０．０２〜０．０４ｗｔ％を含有していることがより好ましい。
【００６１】
上記副成分が上記範囲より少ないと、初透磁率は向上するが直流重畳下での実効透磁率が低下してしまい、また、上記範囲より多いと初透磁率が低下し、さらには異常粒成長を促進してしまい直流重畳下での実効透磁率の低下を引き起こしてしまう。
【００６２】
【発明の効果】本発明によれば、室温（２５℃）の１００ｋＨｚの初透磁率が４０００以上であり、−４０〜８５℃の範囲でＨｄｃ（直流磁界）が１０ＡＴ／ｍの時の透磁率が３０００以上、Ｈｄｃが２０ＡＴ／ｍの時の透磁率が２５００以上、Ｈｄｃが３０ＡＴ／ｍの時の透磁率が２０００以上、Ｈｄｃが４０ＡＴ／ｍの時の透磁率が１５００以上のＭｎ−Ｚｎ系フェライトを得ることができる。
【００６３】
これにより本発明では、イーサーネット用ＬＡＮカード等のトランスコアとして、１００Ｍビット／秒で利用でき、さらに−４０〜８５℃の広温度帯域で使用できるフェライトコアを提供できる。[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be used at 100 Mbit / s (100Base-T) used as a transformer core of an Ethernet LAN (Local Area Network) card or the like. The present invention relates to a Mn—Zn-based oxide magnetic material that exhibits excellent characteristics in a wide temperature range.
[0002]
2. Description of the Related Art Mn-Zn ferrite has a high magnetic permeability and is therefore used as a magnetic core for transformers and noise filters.
[0003]
In recent years, the communication frequency of a LAN to which a terminal such as a personal computer is connected has been increased, and high-speed Ethernet has become widespread. Furthermore, the specification of the current temperature band was from 0 to 70 ° C., but it has been shifted to a new type of −40 to 85 ° C. in order to be able to cope with operation in a severe operating environment.
[0004]
Therefore, in order to cope with these problems, a transformer for an Ethernet LAN card which can be used at 100 Mbit / s requires a ferrite core having excellent DC superimposition characteristics particularly in a wide temperature band of -40 to 85 ° C.
[0005]
However, none of the conventional Mn-Zn-based ferrites has excellent direct-current superposition characteristics in the wide temperature range of -40 to 85 ° C. If the target effective magnetic permeability μe under DC superimposition is obtained at −40 ° C., the target at 85 ° C. cannot be obtained. If the target μe under DC superimposition at 85 ° C. is obtained, the target at −40 ° C. Couldn't get the goal. For this reason, it is very inefficient, for example, it is necessary to increase the number of windings in order to secure an inductance in accordance with the lower μe.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a Mn-Zn ferrite having a high magnetic permeability even in a superimposed direct current in a wide temperature range of -40 to 85 ° C.
[0007]
The object of the present invention can be achieved by the following (1) to (4).
[0008]
(1) Iron oxide as a main component is 53 to 54 mol% in terms of Fe ₂ O _3.
Manganese oxide is 26 to 27.5 mol% in terms of MnO.
19 to 21 mol% of zinc oxide in terms of ZnO
Consisting of
0.01 to 0.02 wt% of SiO ₂ is added as a sub component to the main component.
0.015-0.045wt% CaO
Nb ₂ O ₅ is 0.01 to 0.05 wt%
Ferrite for a LAN card for a wide temperature band of -40 to 85 ° C, characterized by containing.
[0009]
(2) As the main component, particularly, iron oxide is 53 to 53.5 mol% in terms of Fe ₂ O _3.
Manganese oxide in an amount of 26 to 26.5 mol% in terms of MnO
19.5 to 20.5 mol% of zinc oxide in terms of ZnO
The ferrite for a LAN card for a wide temperature band of -40 to 85 [deg.] C. according to the above (1), comprising:
[0010]
(3) 0.01 to 0.015 wt% of SiO ₂ as the subcomponent
0.03-0.04 wt% CaO
0.02 to 0.04 wt% of Nb ₂ O ₅
The ferrite for a LAN card for a wide temperature band of −40 to 85 ° C. according to the above (1), which is contained.
[0011]
(4) Iron oxide as a main component is 53 to 54 mol% in terms of Fe ₂ O _3.
Manganese oxide is 26 to 27.5 mol% in terms of MnO.
19 to 21 mol% of zinc oxide in terms of ZnO
Consisting of
0.01 to 0.02 wt% of SiO ₂ is added as a sub component to the main component.
0.015-0.045wt% CaO
Nb ₂ O ₅ is 0.01 to 0.05 wt%
Wherein the ferrite contained is fired in an atmosphere having an oxygen partial pressure of 10% or less (but not including 0) in a stable portion of the firing step, wherein the LAN card is for a wide temperature band of -40 to 85 ° C. Manufacturing method of ferrite for steel.
[0012]
Thereby, the following effects can be obtained.
[0013]
In the present invention, the initial magnetic permeability at 100 kHz at room temperature (25 ° C.) is 4000 or more, and the magnetic permeability at Hdc (DC magnetic field) of 10 AT / m is 3000 or more and Hdc is 20 AT in a range of −40 to 85 ° C. / M, a magnetic permeability of 2500 or more when Hdc is 30 AT / m, and a magnetic permeability of 2000 or more when Hdc is 40 AT / m.
[0014]
As a result, the present invention can provide a ferrite core that can be used at 100 Mbit / s and can be used in a wide temperature band of -40 to 85 ° C. as a transformer core for an Ethernet LAN card or the like.
[0015]
Embodiments of the present invention will be described.
[0016]
In the present invention, Fe ₂ O ₃ , Mn ₃ O ₄ , and ZnO were used as starting materials of the main components, and the respective materials were weighed such that the composition after sintering became as shown in Table 1 described below. These were wet-mixed, dried with a spray drier, and calcined at 900 ° C. for 2 hours in the atmosphere.
[0017]
Next, the calcined product of the main component and the subcomponent were mixed as described below. That is, the calcined product of the main component material contained 0.015 wt% of SiO ₂ , 0.04 wt% of CaO, and 0.02 wt% of Nb ₂ O ₅ as subcomponents, and were mixed while pulverizing. The pulverization was performed until the average particle size of the calcined product became about 1.5 μm.
[0018]
Polyvinyl alcohol (PVA) was added as a binder to the mixture thus obtained, and the mixture was granulated with a spray drier. This powder was molded under pressure at a pressure of 1 ton / cm ² to obtain a toroidal core sample. Got.
[0019]
The obtained toroidal core sample was heated at a temperature rising rate of 300 ° C./Hr at room temperature to 900 ° C. and at a temperature of 900 ° C./Hr at a stable temperature of 100 ° C./Hr in the firing step. did.
[0020]
The stable temperature was 1360 ° C., and the oxygen concentration in the stable portion was 5%.
[0021]
The cooling zone from the stable temperature to 1000 ° C. was controlled at an oxygen partial pressure equal to or lower than the oxygen partial pressure of the stable part.
[0022]
The initial magnetic permeability μi of each obtained toroidal core at 25 ° C. at 100 kHz and the effective magnetic permeability μe at Hdc of −40 ° C. and 85 ° C. at 10 AT / m, 20 AT / m, 30 AT / m, and 40 AT / m. It was measured. Note that an impedance analyzer was used for measuring the initial magnetic permeability and the effective magnetic permeability.
[0023]
Table 1 shows the initial magnetic permeability μi of 100 kHz at room temperature (25 ° C.) and the effective magnetic permeability μe of Hdc at −40 ° C. and 85 ° C. of 10, 20, 30, and 40 AT / m.
[0024]
[Table 1]

[0025]
In Table 1, Sample No. Sample Nos. 1 to 3 show examples of the present invention. Reference numerals 4 to 15 are comparative examples for comparing characteristics.
[0026]
As shown in Table 1, in Examples of the present invention, the initial magnetic permeability at 100 kHz at room temperature (RT) is 4000 or more, and the effective magnetic permeability when Hdc is 10 AT / m at -40 ° C and 85 ° C. Effective permeability is 3000 or more when Hdc is 20 AT / m, effective permeability is 2500 or more, when Hdc is 30 AT / m, effective permeability is 2000 or more, and when Hdc is 40 AT / m, effective permeability is 1500 or more. It turns out to be something.
[0027]
When the content of Fe ₂ O ₃ is less than 53 mol%, the effective magnetic permeability at 85 ° C. at 30 AT / m and 40 AT / m does not reach 2000 and 1500 and is small (see Sample No. 9).
[0028]
When Fe ₂ O ₃ is more than 54 mol%, the initial magnetic permeability is small, and the effective magnetic permeability at 10 ° C./30 AT / m at 85 ° C. does not reach 3000 or 2000 (sample numbers No. 5 and No. 13). reference).
[0029]
If MnO is less than 26 mol%, the effective magnetic permeability at 85 ° C at 30 AT / m and 40 AT / m does not reach 2000 and 1500 and is small (see Sample No. 7).
[0030]
When MnO is more than 27.5 mol%, the effective magnetic permeability at 10 AT / m at 85 ° C. does not reach 3000 and is small (see Sample No. 13).
[0031]
If ZnO is less than 19 mol%, the initial magnetic permeability does not reach 4000 and is small, or the effective magnetic permeability at 85 ° C. at 40 AT / m does not reach 1500 and is small (see Sample No. 8).
[0032]
If ZnO is more than 21 mol%, the effective magnetic permeability at 85 ° C at 30 AT / m does not reach 2000 and is small, or the effective magnetic permeability at 40 AT / m does not reach 1500 and is small (see Sample No. 9). ).
[0033]
In particular, when Fe ₂ O ₃ is 53 to 53.5 mol%, MnO is 26 to 26.5 mol%, and ZnO is 19.5 to 20.5 mol%, sample No. 1, No. As shown in FIG. 2, the initial permeability and the effective permeability at 10 AT / m, 20 AT / m, and 30 AT / m at -40 ° C. are large, and the effective permeability at 10 ° C., 20 AT / m, and 30 AT / m at 85 ° C. It can be seen that the magnetic permeability is also large.
[0034]
Table 2 shows the characteristics when the atmosphere of the oxygen partial pressure in the stable part in the ferrite firing step was set to different values. Table 2 shows the sample number No. of Table 1. 1 sample i.e., ferrite _Fe 2 _O 3 _53.25mol% as a main _{component, MnO26.50mol%, ZnO20.25mol%, SiO} 2 0.015wt% as an auxiliary _{component, CaO0.04wt%, Nb 2 O 5} 0. Initial permeability μi of 100 kHz at room temperature when the atmosphere composed of 02 wt% is used and the atmosphere of the oxygen partial pressure in the stable part of the firing step is changed every 5% within the range of 5% to 20%. Table 2 shows the effective magnetic permeability μe when the Hdc at ° C and 85 ° C is 10, 20, 30, and 40 AT / m.
[0035]
[Table 2]

[0036]
In Table 2, Sample No. Sample Nos. 1 and 2 show examples of the present invention. Reference numerals 3 and 4 are comparative examples for comparing characteristics.
[0037]
From Table 2, it can be seen that Sample No. No. in which the atmosphere of the oxygen partial pressure in the stable part of the firing step according to the embodiment of the present invention is 10% or less, 5% or 10%. In the case of 1 or 2, the initial magnetic permeability is 4000 or more, the effective magnetic permeability when Hdc is 10 AT / m in the range of −40 ° C. to 85 ° C. is 3000 or more, and the effective magnetic permeability when Hdc is 20 AT / m. It can be seen that excellent characteristics are exhibited in which the effective permeability is 2,000 or more when the permeability is 2500 or more and Hdc is 30 AT / m, and the effective permeability is 1500 or more when the Hdc is 40 AT / m.
[0038]
However, the sample number No. The numbers 3 and 4 show that the Hdc at -40 ° C. and 85 ° C. are 30 AT / m, and the effective magnetic permeability at 40 AT / m does not reach 2000 and 1500 and is small.
[0039]
Next, the subcomponent will be described.
[0040]
First, the starting materials are weighed so that the final composition becomes 53.25 mol% of Fe ₂ O _3, 26.50 mol% of MnO, and 20.25 mol% of ZnO as a basic composition, and they are wet-mixed. And calcined in the air at 900 ° C. for 2 hours.
[0041]
Then, the calcined product of the main component raw material and the sub-component of wt% shown in Table 3 were mixed (1.00 ppm = 0.01%).
[0042]
After adding PVA as a binder to the obtained mixture and granulating it with a spray drier, this powder was subjected to pressure molding at a pressure of 1 ton / cm ² to obtain a toroidal core sample.
[0043]
The obtained toroidal magnetic core sample was heated in a heating step at a temperature rising rate of room temperature to 900 ° C. at 300 ° C./Hr, and 900 ° C. to stable temperature at 100 ° C./Hr. And
[0044]
The stable temperature was 1360 ° C., and the oxygen concentration in the stable portion was 5%.
[0045]
The cooling zone from the stable temperature to 1000 ° C. was controlled at an oxygen partial pressure equal to or lower than the oxygen partial pressure of the stable part.
[0046]
The initial permeability μi of 100 kHz at 25 ° C. and the effective permeability of Hdc at −40 ° C. and 85 ° C. of 10, 20, 30, and 40 AT / m at 25 ° C. were measured for each of the obtained toroidal cores. An impedance analyzer was used for measuring the initial magnetic permeability and the effective magnetic permeability.
[0047]
Table 3 shows the initial magnetic permeability at 100 kHz at room temperature (25 ° C.) and the effective magnetic permeability when the Hdc at −40 ° C. and 85 ° C. is 10, 20, 30, and 40 AT / m.
[0048]
[Table 3]

[0049]
In Table 3, Sample No. Sample Nos. 1 to 9 show examples of the present invention. 10 to 16 are comparative examples for comparing characteristics.
[0050]
As shown in Table 3, in Examples of the present invention, the initial magnetic permeability at 100 kHz at room temperature is 4000 or more, and the effective magnetic permeability at -40 ° C and 85 ° C when Hdc is 10 AT / m is 3000 or more, and Hdc is The effective magnetic permeability at 20AT / m is 2500 or more, the effective magnetic permeability at Hdc of 30AT / m is 2000 or more, and the effective magnetic permeability at Hdc of 40AT / m is 1500 or more. Understand.
[0051]
When the content of SiO ₂ is less than 0.01 wt%, the effective magnetic permeability of 30 AT / m and 40 AT / m at 85 ° C. does not reach 2000 and 1500 and is small (see Sample No. 10).
[0052]
When SiO ₂ is more than 0.02 wt%, the initial magnetic permeability does not reach 4000, and the effective magnetic permeability at −40 ° C. when Hdc is 10 AT / m and 30 AT / m does not reach 3000 or 2000 and is small (sample No. 16).
[0053]
If the CaO content is less than 0.015 wt%, the effective magnetic permeability at 85 ° C. when the Hdc is 30 AT / m and 40 AT / m does not reach 2000 and 1500 and is small (see Sample No. 17).
[0054]
If CaO is more than 0.045 wt%, the effective magnetic permeability at -40 ° C when the Hdc is 10 AT / m and 20 AT / m does not reach 3000 and 2500, and the effective permeability when the Hdc at 85 ° C is 40 AT / m. The magnetic permeability does not reach 1500 and is small (see Sample No. 13).
[0055]
When Nb ₂ O ₅ is less than 0.01 wt%, the effective magnetic permeability at -40 ° C. when Hdc is 40 AT / m does not reach 1500, and when Hdc at 85 ° C. is 30 AT / m and 40 AT / m. The effective magnetic permeability does not reach 2000 and 1500 and is small (see Sample No. 14).
[0056]
When Nb ₂ O ₅ is more than 0.05 wt%, the initial magnetic permeability does not reach 4000, and the effective magnetic permeability when Hdc at −40 ° C. is 10 AT / m and 20 AT / m does not reach 3000 and 2500 and is small ( (See Sample No. 15).
[0057]
In particular, when SiO ₂ is contained at 0.01 to 0.015 wt%, CaO is contained at 0.03 to 0.04 wt%, and Nb ₂ O ₅ is contained at 0.02 to 0.04 wt%, the sample No. 1, No. As shown in FIGS. 6 to 8, it can be seen that the effective magnetic permeability at Hdc of 20 AT / m and 30 AT / m at −40 ° C. and 85 ° C. is excellent. The Hdc 20 AT / m and 30 AT / m are relatively large ranges of use frequency.
[0058]
The substantial main components in the ferrite core of the present invention are as follows: iron oxide is 53 to 54 mol% in terms of Fe ₂ O ₃ , manganese oxide is 26 to 27.5 mol% in terms of MnO, and zinc oxide is 19 to 21 mol% in terms of ZnO. in the configuration, 53～53.5Mol% iron oxide calculated as _Fe 2 _{O 3,} 26～26.5Mol% manganese oxide in terms of MnO, it is composed of zinc oxide in 19.5～20.5Mol% calculated as ZnO More preferably.
[0059]
In the case of Mn-Zn ferrite, the temperature dependence curve of the initial permeability has two peaks. When a peak having a relatively high initial permeability is defined as a primary peak and a relatively low peak is defined as a secondary peak, the primary peak exists on the high temperature side and the secondary peak exists on the low temperature side. If the composition ratio of the main component is out of the above range, the secondary peak and the primary peak move in the low temperature direction or the high temperature direction, and it becomes impossible to obtain good characteristics at -40 ° C or 85 ° C.
[0060]
In the present invention, the sub-components are 0.01 to 0.02 wt% in terms of SiO ₂ , 0.015 to 0.045 wt% in terms of CaO, and 0.01 to 0.05 wt% in terms of Nb ₂ O ₅ with respect to the main components. it is preferable to contain 05wt%, 0.01~0.015wt% in terms of SiO _2, 0.03～0.04Wt% in terms of CaO, a 0.02～0.04Wt% calculated as _Nb 2 _{O 5} More preferably, it is contained.
[0061]
When the above-mentioned subcomponent is less than the above range, the initial permeability is improved, but the effective permeability under DC superposition is reduced. When the above-mentioned subcomponent is more than the above range, the initial permeability is reduced, and further, abnormal grain growth is caused. And the effective magnetic permeability under DC superposition is reduced.
[0062]
According to the present invention, the initial magnetic permeability at room temperature (25 ° C.) at 100 kHz is 4000 or more, and the magnetic permeability when the Hdc (DC magnetic field) is 10 AT / m in the range of −40 to 85 ° C. -Mn-Zn based material having a magnetic permeability of 3000 or more, a magnetic permeability of 2500 AT or more when Hdc is 20 AT / m, a magnetic permeability of 2000 or more when Hdc of 30 AT / m, and a magnetic permeability of 1500 or more when Hdc is 40 AT / m. Ferrite can be obtained.
[0063]
As a result, the present invention can provide a ferrite core that can be used at 100 Mbit / s and can be used in a wide temperature band of -40 to 85 ° C. as a transformer core for an Ethernet LAN card or the like.

Claims (4)

53～54Mol% in iron oxide in terms _{of Fe} 2 _{O 3} as main components
Manganese oxide is 26 to 27.5 mol% in terms of MnO.
19 to 21 mol% of zinc oxide in terms of ZnO
Consisting of
0.01 to 0.02 wt% of SiO ₂ is added as a sub component to the main component.
0.015-0.045wt% CaO
Nb ₂ O ₅ is 0.01 to 0.05 wt%
Ferrite for a LAN card for a wide temperature band of -40 to 85 ° C, characterized by containing. As the main component, particularly, iron oxide is 53 to 53.5 mol% in terms of Fe ₂ O _3.
Manganese oxide in an amount of 26 to 26.5 mol% in terms of MnO
19.5 to 20.5 mol% of zinc oxide in terms of ZnO
The ferrite for a LAN card for a wide temperature band of -40 to 85 [deg.] C. according to claim 1, characterized by comprising: In particular, 0.01 to 0.015 wt% of SiO ₂ is used as the subcomponent.
0.03-0.04 wt% CaO
0.02 to 0.04 wt% of Nb ₂ O ₅
2. The ferrite for a LAN card for a wide temperature band of -40 to 85 [deg.] C. according to claim 1, wherein the ferrite is contained. 53～54Mol% in iron oxide in terms _{of Fe} 2 _{O 3} as main components
Manganese oxide is 26 to 27.5 mol% in terms of MnO.
19 to 21 mol% of zinc oxide in terms of ZnO
Consisting of
0.01 to 0.02 wt% of SiO ₂ is added as a sub component to the main component.
0.015-0.045wt% CaO
Nb ₂ O ₅ is 0.01 to 0.05 wt%
Wherein the ferrite contained is fired in an atmosphere having an oxygen partial pressure of 10% or less (but not including 0) in a stable portion of the firing step, wherein the LAN card is for a wide temperature band of -40 to 85 ° C. Manufacturing method of ferrite for steel.