JP2006199510A - HIGH SATURATION MAGNETIC FLUX DENSITY Mn-Zn-Ni-BASED FERRITE - Google Patents
HIGH SATURATION MAGNETIC FLUX DENSITY Mn-Zn-Ni-BASED FERRITE Download PDFInfo
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Abstract
Description
本発明は、スイッチング電源等の電源トランス、特にフライバック方式の電源トランス等に用いて好適な、高い飽和磁束密度を有するMn−Zn−Ni系フェライトに関するものである。 The present invention relates to an Mn-Zn-Ni ferrite having a high saturation magnetic flux density, which is suitable for use in a power supply transformer such as a switching power supply, particularly a flyback power supply transformer.
フェライトと称される酸化物磁性材料は、Ba系フェライト、Sr系フェライトなどの硬質磁性材料と、Mn−Zn系フェライト、Ni−Zn系フェライトなどの軟質磁性材料とに分類される。このうち、軟質磁性材料は、非常にわずかな磁場に対しても十分に磁化されるため、電源や通信機器、計測制御機器、コンピュータなど、多方面の分野において用いられている。そのため、これらの軟磁性材料には、飽和磁束密度が大きいことのほか、保磁力が小さくて透磁率が高いこと、磁気損失が小さいことなどの特性が要求されている。 Oxide magnetic materials called ferrite are classified into hard magnetic materials such as Ba-based ferrite and Sr-based ferrite and soft magnetic materials such as Mn-Zn-based ferrite and Ni-Zn-based ferrite. Among these, the soft magnetic material is sufficiently magnetized even with a very small magnetic field, and is therefore used in various fields such as a power supply, communication equipment, measurement control equipment, and a computer. Therefore, these soft magnetic materials are required to have characteristics such as a high saturation magnetic flux density, a low coercive force and a high magnetic permeability, and a low magnetic loss.
軟磁性材料には、上記フェライト以外に、金属系のものがある。この金属系の軟磁性材料は、飽和磁束密度が高いという特長を有している反面、高周波帯域で使用する場合には、電気抵抗が低いため、渦電流に起因する損失が大きくなって低損失を維持できないという問題がある。そのため、金属系磁性材料は、電子機器の小型化・高密度化に伴い、使用周波数帯域の高周波化が進む今日では、特に、スイッチング電源等に用いられている100ｋＨz程度の周波数帯域では、渦電流損による発熱が大きくなるので用いることができない。 In addition to the ferrite, the soft magnetic material includes a metallic material. This metal-based soft magnetic material has a feature that the saturation magnetic flux density is high, but when used in a high frequency band, the electrical resistance is low, so the loss due to eddy current increases and the loss is low. There is a problem that cannot be maintained. For this reason, metallic magnetic materials are eddy currents in the frequency band of about 100 kHz, which is used for switching power supplies and the like today, as the frequency of use increases as electronic devices become smaller and more dense. It cannot be used because heat generation due to damage increases.
このような背景から、現在、高周波帯域で用いられている電源用トランスの磁心材料としては、酸化物系のフェライト、中でも、Mn−Zn系フェライトが主に用いられている。この高周波電源用のMn−Zn系フェライトには、キュリー温度Ｔcが高いこと、飽和磁束密度Ｂsが高いこと、および磁気損失Ｐcvが低いことが要求される。これらの特性のうち、キュリー温度Ｔc、飽和磁束密度Ｂsは、磁気モーメントを有する金属原子の種類、ならびにその金属原子が占める位置により変化することが知られており、主成分の組成によりほぼ決定される。 Against this background, oxide-based ferrites, especially Mn-Zn-based ferrites, are mainly used as magnetic core materials for power transformers currently used in the high frequency band. This Mn-Zn ferrite for a high frequency power supply is required to have a high Curie temperature Tc, a high saturation magnetic flux density Bs, and a low magnetic loss Pcv. Among these characteristics, the Curie temperature Tc and the saturation magnetic flux density Bs are known to vary depending on the type of metal atom having a magnetic moment and the position occupied by the metal atom, and are almost determined by the composition of the main component. The
ところで、近年、電子機器の電源部分は、小型化への要請に応えるため、各種部品が高密度に積載され、それら部品からの発熱により高温化する傾向にある。その結果、フェライトコアが使用される温度、つまり動作温度は、80〜100℃にも達することがある。一般に、酸化物系フェライトの飽和磁束密度は、温度の上昇とともに減少し、キュリー温度Ｔcで磁気が消失しゼロとなる。したがって、キュリー温度が高いほど、室温からトランス動作温度(80〜100℃)までの飽和磁束密度を高く維持することができる。一般に、キュリー温度や飽和磁束密度は、基本組成であるFe2Ｏ3の量が多いほど高くなることが知られており、例えば、特許文献１には、Fe2Ｏ3量を増やすことにより飽和磁束密度を高める技術が開示されている。 By the way, in recent years, in order to meet the demand for miniaturization, the power supply portion of electronic equipment has a tendency that various parts are loaded with high density and heated by heat generated from these parts. As a result, the temperature at which the ferrite core is used, that is, the operating temperature may reach 80 to 100 ° C. In general, the saturation magnetic flux density of an oxide-based ferrite decreases as the temperature rises, and the magnetism disappears and becomes zero at the Curie temperature Tc. Therefore, the higher the Curie temperature, the higher the saturation magnetic flux density from room temperature to the transformer operating temperature (80 to 100 ° C.) can be maintained. In general, it is known that the Curie temperature and the saturation magnetic flux density increase as the amount of Fe 2 O 3 that is the basic composition increases. For example, in Patent Document 1, saturation is achieved by increasing the amount of Fe 2 O 3. A technique for increasing the magnetic flux density is disclosed.
一方、フェライトの磁気損失Ｐcvについては、それを支配する要因として、磁気異方性定数Ｋ1ならびに飽和磁歪定数λsが知られており、従来から、Mn−Zn系フェライトにおいては、これらのパラメータの値を小さくするようなMnＯ−ZnＯ−Fe2Ｏ3三元系の組成領域が選択されている。すなわち、磁気損失Ｐcvが小さい組成領域とは、電源用トランスの動作温度(80℃〜100℃)において、磁気異方性定数Ｋ1ならびに飽和磁歪定数λsがともに小さい三元系組成領域であり、具体的には、Fe2Ｏ3が52〜54mol％、ZnＯが10〜16mol％付近の組成領域である。したがって、磁気損失は、この領域から外れるにつれて増加の一途をたどることになる。 On the other hand, as for the magnetic loss Pcv of ferrite, the magnetic anisotropy constant K 1 and the saturation magnetostriction constant λ s are known as factors governing it. Conventionally, in Mn-Zn ferrite, these parameters are An MnO—ZnO—Fe 2 O 3 ternary composition region that reduces the value is selected. That is, the composition region having a small magnetic loss Pcv is a ternary composition region in which both the magnetic anisotropy constant K 1 and the saturation magnetostriction constant λ s are small at the operating temperature (80 ° C. to 100 ° C.) of the power transformer. Specifically, it is a composition region in which Fe 2 O 3 is 52 to 54 mol% and ZnO is about 10 to 16 mol%. Thus, the magnetic loss will continue to increase as it moves out of this region.
また、Mn−Zn系フェライトの磁気損失Ｐcvは、温度による変化が大きいため、基本成分組成は、動作温度付近で磁気異方性定数Ｋ1がゼロとなるような範囲を選択しているが、従来のMn−Zn系フェライト(MnＯ−ZnＯ−Fe2Ｏ3三元系フェライト)では、飽和磁束密度を高めるためにFe2Ｏ3量を増していくと、磁気損失が最小となる温度は低温側に変化する。そのため、Fe2Ｏ3量を増加し、磁気損失が最小となる温度が室温付近まで低下した場合には、動作温度(80℃〜100℃)での磁気損失は非常に大きな値となってしまう。 In addition, since the magnetic loss Pcv of the Mn-Zn ferrite varies greatly with temperature, the basic component composition is selected in such a range that the magnetic anisotropy constant K 1 is zero near the operating temperature. In the conventional Mn-Zn ferrite (MnO-ZnO-Fe 2 O 3 ternary ferrite), the temperature at which the magnetic loss is minimized becomes lower as the amount of Fe 2 O 3 is increased to increase the saturation magnetic flux density. Change to the side. Therefore, when the amount of Fe 2 O 3 is increased and the temperature at which the magnetic loss is minimized decreases to near room temperature, the magnetic loss at the operating temperature (80 ° C. to 100 ° C.) becomes a very large value. .
しかし、Fe2Ｏ3の量を、従来の範囲を超えてさらに増やしていくと、ZnＯの量によっても異なるが、凡そ60mol％を境にして、磁気損失が最小となる温度が低下から上昇に転じることが知られている（例えば、非特許文献１参照）。したがって、Fe2Ｏ3量の多い組成領域でも、基本成分を調整することにより、動作温度付近で磁気損失が最小となるようにすることができる。先述した特許文献１の技術でも、この付近の組成を選択、使用している。
ところが、MnＯ−ZnＯ−Fe2Ｏ3三元系においては、飽和磁束密度を高めるために、Fe2Ｏ3の含有量を60mol％超えまで増やすと、磁気損失が最小となる温度を動作温度付近とすることができる反面、飽和磁歪定数λsに対する最適組成領域から外れるため、磁気損失自体は増大する。したがって、従来は、高い飽和磁束密度を確保するために磁気損失を犠牲にするか、あるいは、磁気損失を優先して従来材並みの飽和磁束密度で満足するかのいずれかでしかなかった。この間題に対して、発明者らは、Fe2Ｏ3量が従来材より多い組成においては、NiＯを基本成分に加えることにより、飽和磁束密度を高い値に維持したまま損失を低くすることができることを見出し、特願2003−420414に提案した。この技術によれば、従来材に比べると高い飽和磁束密度Ｂsを得ることができる。しかし、近年における、電子機器の電源部分のさらなる小型化と高集積化への要請に応えるには、飽和磁束密度をより高めると同時に、磁気損失をより低減させて、発熱量を低減した材料の開発が必要とされている。 However, in the MnO-ZnO-Fe 2 O 3 ternary system, in order to increase the saturation magnetic flux density, when the content of Fe 2 O 3 is increased to over 60 mol%, the temperature at which the magnetic loss is minimized is near the operating temperature. However, the magnetic loss itself increases because it deviates from the optimum composition region for the saturation magnetostriction constant λs. Therefore, in the past, the magnetic loss was sacrificed in order to ensure a high saturation magnetic flux density, or the saturation loss density equivalent to that of the conventional material was satisfied in favor of the magnetic loss. In response to this problem, the inventors can reduce the loss while maintaining the saturation magnetic flux density at a high value by adding NiO to the basic component in a composition having a larger amount of Fe 2 O 3 than the conventional material. We found out what we can do and proposed it in Japanese Patent Application 2003-420414. According to this technique, a high saturation magnetic flux density Bs can be obtained as compared with the conventional material. However, in order to meet the recent demand for further miniaturization and higher integration of the power supply part of electronic equipment, the saturation magnetic flux density is further increased, and at the same time, the magnetic loss is further reduced to reduce the heat generation amount. Development is needed.
本発明の目的は、電源用トランス、特にフライバック方式のスイッチング電源用トランスとして好適な、高い飽和磁束密度と低い磁気損失を兼ね備えたMn−Zn−Ni系フェライトを提供することにある。 An object of the present invention is to provide an Mn—Zn—Ni ferrite having both a high saturation magnetic flux density and a low magnetic loss, which is suitable as a power transformer, particularly a flyback switching power transformer.
発明者らは、Fe2Ｏ3量が多く(＞60mol％)かつNiＯを基本成分に含むMn−Zn−Ni系フェライトは、従来のFe2Ｏ3が52〜54mol％、ZnＯが10〜16mol％付近の組成を有するフェライトと比較して、飽和磁束密度Ｂsが高い反面、電気抵抗が一桁ほど小さく、そのため、高周波領域では渦電流損失が増加し、大きな発熱につながっていることに着目し、この電気抵抗を増大せしめる効果のある微量添加成分について鋭意研究を重ねた。その結果、添加成分として、Na，Ｋを含む化合物を添加した場合には、高い飽和磁束密度損なうことなく、電気抵抗を増加し、磁気損失を低減できることを見いだし、本発明を完成するに至った。 The inventors found that Mn-Zn-Ni based ferrite containing a large amount of Fe 2 O 3 (> 60 mol%) and NiO as a basic component is 52 to 54 mol% of conventional Fe 2 O 3 and 10 to 16 mol of ZnO. The saturation magnetic flux density Bs is higher than that of ferrite having a composition of about 100%, but the electrical resistance is about an order of magnitude lower. Therefore, eddy current loss increases in the high frequency region, which leads to large heat generation. , And earnestly researched about the additive component with the effect of increasing the electrical resistance. As a result, when a compound containing Na and K was added as an additive component, it was found that the electrical resistance can be increased and the magnetic loss can be reduced without losing a high saturation magnetic flux density, and the present invention has been completed. .
すなわち、本発明は、基本成分が、Fe2Ｏ3：58〜64mol％、ZnＯ：８〜14mol％、NiＯ：３〜８mol％、残部が実質的にMnＯからなり、添加成分としてSiＯ2：0.005〜0.05mass％およびCaＯ：0.02〜0.2mass％を含有するMn−Zn−Ni系フェライトにおいて、Na：0.02mass％以下(０を含まず)、Ｋ：0.015mass％以下(０を含まず)のいずれか１種または２種を合計で0.02mass％以下含有し、さらにTa2Ｏ5，ZrＯ2，Nb2Ｏ5，Ｖ2Ｏ5，HfＯ2，Bi2Ｏ3，MoＯ3，TiＯ2およびSnＯ2のうちから選ばれる１種または２種以上を下記範囲で含有することを特徴とする高飽和磁束密度Mn−Zn−Ni系フェライトである。
記
Ta2Ｏ5：0.005〜0.1mass％
ZrＯ2：0.01〜0.15mass％
Nb2Ｏ5：0.005〜0.05mass％
Ｖ2Ｏ5：0.001〜0.05mass％
HfＯ2：0.005〜0.05mass％
Bi2Ｏ3：0.003〜0.03mass％
MoＯ3：0.003〜0.03mass％
TiＯ2：0.01〜0.3mass％
SnＯ2：0.01〜2.0mass％
That is, the present invention is basic component, Fe 2 O 3: 58~64mol% , ZnO: 8~14mol%, NiO: 3~8mol%, balance being substantially MnO, as an additive component SiO 2: 0.005 In an Mn-Zn-Ni ferrite containing 0.05 mass% and CaO: 0.02-0.2 mass%, Na: 0.02 mass% or less (not including 0), K: 0.015 mass% or less (not including 0) One or two of them are contained in a total amount of 0.02 mass% or less, and Ta 2 O 5 , ZrO 2 , Nb 2 O 5 , V 2 O 5 , HfO 2 , Bi 2 O 3 , MoO 3 , TiO 2 and A high saturation magnetic flux density Mn-Zn-Ni-based ferrite containing one or more selected from SnO 2 in the following range.
Record
Ta 2 O 5 : 0.005 to 0.1 mass%
ZrO 2 : 0.01 to 0.15 mass%
Nb 2 O 5 : 0.005 to 0.05 mass%
V 2 O 5: 0.001~0.05mass%
HfO 2 : 0.005 to 0.05 mass%
Bi 2 O 3 : 0.003 to 0.03 mass%
MoO 3 : 0.003 ~ 0.03mass%
TiO 2: 0.01~0.3mass%
SnO 2 : 0.01 to 2.0 mass%
また、本発明のMn−Zn−Ni系フェライトは、100℃における飽和磁束密度が480ｍＴ以上、100ｋＨz、200ｍＴにおける磁気損失が900ｋＷ／ｍ3以下であることを特徴とする。 The Mn-Zn-Ni ferrite of the present invention is characterized in that the saturation magnetic flux density at 100 ° C. is 480 mT or more, and the magnetic loss at 100 kHz and 200 mT is 900 kW / m 3 or less.
本発明によれば、飽和磁束密度が高くかつ磁気損失の小さいMn−Zn−Ni系フェライトを提供することができる。このMn−Zn−Ni系フェライトは、フライバック方式の電源トランスに用いて好適であり、電源部分の発熱を抑制し、ひいては小型化に大いに寄与する。 According to the present invention, it is possible to provide an Mn-Zn-Ni ferrite having a high saturation magnetic flux density and a small magnetic loss. This Mn-Zn-Ni-based ferrite is suitable for use in a flyback power supply transformer, suppresses heat generation in the power supply portion, and greatly contributes to downsizing.
本発明の基本的な技術思想について説明する。
軟磁性材料であるMn−Zn系フェライトに求められる磁気特性としては、キュリー温度Ｔcが高いこと、飽和磁束密度Ｂsが大きいこと、磁気損失Ｐcvが小さいことが挙げられる。これらの特性は、基本成分であるMnＯ：ZnＯ：Fe2Ｏ3の比でほぼ決定される。従来の電源用Mn−Zn系フェライトが採用していたFe2Ｏ3：52〜54mol％、ZnＯ：10〜16mol％の組成領域では、Fe2Ｏ3量の増加にともない飽和磁束密度が増加し、キュリー温度も上昇するが、磁気異方性定数Ｋ1がゼロとなる温度、すなわち磁気損失が最小となる温度も低下するため、トランス動作温度(80〜100℃)での磁気損失が増大する。一方、ZnＯの量が増加すると、損失が最小となる温度が低温側に移行するため、この温度を動作温度付近に維持するためには、相対的にFe2Ｏ3の量を少なくする必要があり、飽和磁束密度の低下を招く。またZnＯ量の増加に伴いキュリー温度も低下する。
The basic technical idea of the present invention will be described.
Magnetic properties required for the Mn-Zn ferrite, which is a soft magnetic material, include a high Curie temperature Tc, a high saturation magnetic flux density Bs, and a low magnetic loss Pcv. These characteristics are almost determined by the ratio of the basic component MnO: ZnO: Fe 2 O 3 . In the composition range of Fe 2 O 3 : 52 to 54 mol% and ZnO: 10 to 16 mol%, which was used in the conventional Mn-Zn ferrite for power supply, the saturation magnetic flux density increased with the increase of Fe 2 O 3 content. The Curie temperature also rises, but the temperature at which the magnetic anisotropy constant K 1 becomes zero, that is, the temperature at which the magnetic loss is minimized, also decreases, so that the magnetic loss at the transformer operating temperature (80-100 ° C.) increases. . On the other hand, when the amount of ZnO increases, the temperature at which the loss is minimized shifts to the low temperature side. Therefore, in order to maintain this temperature near the operating temperature, it is necessary to relatively reduce the amount of Fe 2 O 3. There is a decrease in saturation magnetic flux density. In addition, the Curie temperature decreases as the amount of ZnO increases.
一方、Mn−Zn系フェライトにおいて、Fe2Ｏ3を60mol％超え含有させた場合には、磁気異方性定数Ｋ1がゼロとなる温度がトランス動作温度(80〜100℃)付近となる組成領域においても、Fe2Ｏ3量の増加にともない飽和磁束密度が増加し、キュリー温度も上昇する。しかも、損失が最小となる温度は、従来のMn−Zn系フェライトとは逆に、Fe2Ｏ3量の増加にともない、高温側へシフトする。また、この組成領域では、飽和磁歪定数λsが大きくなるため、従来のMn−Zn系フェライトと比べると、損失値は著しく大きくなる。 On the other hand, in the Mn-Zn ferrite, when the Fe 2 O 3 content exceeds 60 mol%, the composition at which the temperature at which the magnetic anisotropy constant K 1 becomes zero is around the transformer operating temperature (80 to 100 ° C.). Also in the region, as the amount of Fe 2 O 3 increases, the saturation magnetic flux density increases and the Curie temperature also rises. Moreover, the temperature at which the loss is minimized shifts to the high temperature side as the amount of Fe 2 O 3 increases, contrary to the conventional Mn—Zn ferrite. Further, in this composition region, the saturation magnetostriction constant λs becomes large, so that the loss value becomes remarkably large as compared with the conventional Mn-Zn ferrite.
ここで、Fe2Ｏ3を58mol％以上、特に、60mol％を超えて含むMn−Zn系フェライトに、基本成分としてさらにNiＯを加えた場合には、磁気損失が顕著に低下することができる。つまり、主成分のFe2Ｏ3やNiＯの含有量を適正範囲にすれば、飽和磁束密度が大きく低下することなく、この組成領域に特徴的な、高い損失を低減することができる。MnＯ−ZnＯ−Fe2Ｏ3三元系にNiＯを添加することにより磁気損失が低下する理由は明らかではないが、飽和磁歪定数λsが小さくなったためと考えられる。ところが、これらの組成からなる焼結体の比抵抗は、15〜80Ωcmであり、従来組成（Fe2Ｏ3が52〜54mol％、ZnＯが10〜16mol％付近）と比較すると一桁程度小さい。 Here, Fe 2 O 3 of 58 mol% or more, particularly, the Mn-Zn ferrite comprising exceed 60 mol%, in the case where further addition of NiO as the basic component may be magnetic loss is significantly decreased. That is, if the content of the main component Fe 2 O 3 or NiO is set within an appropriate range, the high loss characteristic of this composition region can be reduced without greatly reducing the saturation magnetic flux density. The reason why the magnetic loss is reduced by adding NiO to the MnO—ZnO—Fe 2 O 3 ternary system is not clear, but it is considered that the saturation magnetostriction constant λs is reduced. However, the specific resistance of the sintered body having these compositions is 15 to 80 Ωcm, which is about an order of magnitude smaller than that of the conventional composition (Fe 2 O 3 is about 52 to 54 mol% and ZnO is about 10 to 16 mol%).
一般に、Mn−Zn系フェライトの損失は、渦電流損失、ヒステリシス損失、それ以外の残留損失に分類され、それらのうちの渦電流損失は、電気抵抗が低下すると増加し、とくに高周波になればなるほど顕著に増加する。このことは、Fe2Ｏ3が60mol％以下の従来のフェライトにおいても同様であり、その対策として、粒界に偏析して焼結体の抵抗を高める微量添加成分、例えば、Ta2Ｏ5，ZrＯ2，Nb2Ｏ5，Ｖ2Ｏ5，HfＯ2，Bi2Ｏ3，MoＯ3等を添加して、抵抗値を増加しようとしている。しかし、Fe2Ｏ3が多い(＞60mol％)組成では、これらの成分添加は、抵抗増加に効果があるものの、その効果は従来組成と比べると非常に小さい。そこで、発明者らは、粒界の抵抗増加成分についてさらに研究を重ねた結果、上記添加成分に加えてさらに、アルカリ金属元素であるNa，Ｋを含む化合物を加えた場合には、従来の添加成分よりも顕著に粒界抵抗を高めることができ、損失低減に大きく寄与することを見出したのである。本発明は、上記知見に基づくものである。 In general, the loss of Mn-Zn ferrite is classified into eddy current loss, hysteresis loss, and other residual loss. Among them, the eddy current loss increases as the electric resistance decreases, and especially as the frequency becomes higher. Increase significantly. This is the same for conventional ferrites with Fe 2 O 3 of 60 mol% or less, and as a countermeasure, a small amount of additive that segregates at the grain boundaries and increases the resistance of the sintered body, such as Ta 2 O 5 , ZrO 2 , Nb 2 O 5 , V 2 O 5 , HfO 2 , Bi 2 O 3 , MoO 3, etc. are added to increase the resistance value. However, in a composition with a large amount of Fe 2 O 3 (> 60 mol%), the addition of these components is effective in increasing resistance, but the effect is very small compared to the conventional composition. Therefore, as a result of further research on the resistance increasing component at the grain boundary, the inventors have added conventional compounds when compounds containing Na and K, which are alkali metal elements, are added in addition to the above-described additive components. It has been found that the grain boundary resistance can be remarkably increased as compared with the component, which greatly contributes to loss reduction. The present invention is based on the above findings.
次に、本発明のフェライトの成分組成を上記範囲とする理由について説明する。
Fe2Ｏ3：58〜64mol％
Fe2Ｏ3は、60mol％を超える領域では、その量が多いほど飽和磁束密度を高める働きがある。しかし、64mol％付近まで上昇すると、飽和磁束密度はほぼ飽和し、あるいは低下に転じる。また、Fe2Ｏ3は、多過ぎると、損失が最小となる温度が高くなるため、トランス動作温度での損失が増大する。このような理由から、Fe2Ｏ3の含有量は、上限を64mol％とする。一方、Fe2Ｏ3は、少なくなると、損失が最小となる温度が低温側に移行し、やはり動作温度での損失が増大するが、さらに、Fe2Ｏ3が少なくなって58mol％未満となると、逆に損失が最小となる温度が高温側に移行するため、トランス動作温度での損失は低くなる。しかし、100℃における飽和磁束密度が大きく低下してしまうので、Fe2Ｏ3の下限は58mol％とする。好ましくは、59〜62mol％の範囲である。
Next, the reason why the component composition of the ferrite of the present invention is in the above range will be described.
Fe 2 O 3 : 58 to 64 mol%
Fe 2 O 3 has a function of increasing the saturation magnetic flux density as the amount of Fe 2 O 3 exceeds 60 mol%. However, when it rises to around 64 mol%, the saturation magnetic flux density is almost saturated or starts to decrease. On the other hand, if Fe 2 O 3 is too much, the temperature at which the loss is minimized becomes high, so that the loss at the transformer operating temperature increases. For these reasons, the upper limit of the content of Fe 2 O 3 is 64 mol%. On the other hand, when Fe 2 O 3 decreases, the temperature at which the loss becomes minimum shifts to the low temperature side, and the loss at the operating temperature also increases, but when Fe 2 O 3 decreases and becomes less than 58 mol%. On the other hand, the temperature at which the loss becomes minimum shifts to the high temperature side, so that the loss at the transformer operating temperature becomes low. However, since the saturation magnetic flux density at 100 ° C. is greatly reduced, the lower limit of Fe 2 O 3 is set to 58 mol%. Preferably, it is the range of 59-62 mol%.
ZnＯ：８〜14mol％、
損失が最小となる温度を動作温度とするためには、Fe2Ｏ3の含有量に応じて、ZnＯの含有量を調節する必要がある。本発明のFe2Ｏ3含有量が多い組成のフェライトでは、高い飽和磁束密度を得るためには、ZnＯの組成は、４〜16mol％の範囲であることが好ましく、10〜12mol％付近で最大の飽和磁束密度となる。ただし、ZnＯが少なくなると損失値が著しく増加するため、ZnＯの下限を８mol％とする。好ましくは、10〜14mol％である。
ZnO: 8-14 mol%,
In order to set the temperature at which the loss is minimized to the operating temperature, it is necessary to adjust the ZnO content in accordance with the Fe 2 O 3 content. In the ferrite having a high Fe 2 O 3 content of the present invention, in order to obtain a high saturation magnetic flux density, the composition of ZnO is preferably in the range of 4 to 16 mol%, and the maximum is around 10 to 12 mol%. Saturation magnetic flux density. However, since the loss value increases remarkably when ZnO decreases, the lower limit of ZnO is 8 mol%. Preferably, it is 10-14 mol%.
NiＯ：３〜８mol％
NiＯは、MnＯ−ZnＯ−Fe2Ｏ3三元系に加えることにより、飽和磁歪定数λsを小さくして磁気損失を低減する効果を有する。しかし、NiＯの含有量が３mol％未満では、この改善効果が小さい。一方、NiＯの含有量を増やすと、損失が最小となる温度が高温側にシフトして行くが、８mol％を超えた場合には、Fe2Ｏ3やZnＯの量を調整しても、損失が最小となる温度を動作温度付近に維持できなくなる。よって、NiＯは３〜８mol％の範囲とする。好ましくは、５〜８mol％である。
NiO: 3-8 mol%
NiO has the effect of reducing the magnetic loss by reducing the saturation magnetostriction constant λs by adding to the MnO—ZnO—Fe 2 O 3 ternary system. However, when the content of NiO is less than 3 mol%, this improvement effect is small. On the other hand, when the content of NiO is increased, the temperature at which the loss is minimized shifts to the higher temperature side. However, if the content exceeds 8 mol%, the loss is reduced even if the amount of Fe 2 O 3 or ZnO is adjusted. It becomes impossible to maintain the temperature at which the minimum is near the operating temperature. Therefore, NiO is in the range of 3 to 8 mol%. Preferably, it is 5 to 8 mol%.
本発明のMn−Zn−Ni系フェライトは、上記基本成分に、添加成分としてSiＯ2，CaＯを下記の範囲で添加する必要がある。
SiＯ2：0.005〜0.05mass％
SiＯ2は、粒界を高抵抗化すると共に、焼結を促進する効果があり、その効果を引き出すためには0.005mass％以上の添加が必要である。しかし、多すぎた場合には、異常粒成長を起こすため、上限を0.05mass％とする。ただし、この上限付近の添加量では、粒成長を抑止して最適な結晶組織とするために、焼結温度を下げる等の配慮が必要である。好ましい添加量は、0.005〜0.02mass％である。
In the Mn-Zn-Ni ferrite of the present invention, it is necessary to add SiO 2 and CaO as additive components in the following range to the above basic components.
SiO 2: 0.005~0.05mass%
SiO 2 has the effect of increasing the resistance of the grain boundary and promoting sintering, and 0.005 mass% or more is necessary to bring out the effect. However, if the amount is too large, abnormal grain growth occurs, so the upper limit is made 0.05 mass%. However, with the addition amount in the vicinity of this upper limit, it is necessary to consider such as lowering the sintering temperature in order to suppress grain growth and obtain an optimum crystal structure. A preferable addition amount is 0.005 to 0.02 mass%.
CaＯ：0.02〜0.2mass％
CaＯは、SiＯ2とともに、粒界を高抵抗化して磁気損失を小さくする働きがある。0.02mass％未満ではその効果が得られず、一方、0.2mass％を超えると、焼結密度が低下するので、0.2mass％以下とする。好ましい添加量の範囲は、0.01〜0.1mass％である。
CaO: 0.02 to 0.2 mass%
CaO, together with SiO 2 , works to increase the resistance of grain boundaries and reduce magnetic loss. If it is less than 0.02 mass%, the effect cannot be obtained. On the other hand, if it exceeds 0.2 mass%, the sintered density is lowered, so that it is 0.2 mass% or less. The range of preferable addition amount is 0.01 to 0.1 mass%.
本発明のMn−Zn−Ni系フェライトは、上記基本成分、添加成分に加えてさらに、Na，Ｋの１種または２種を下記の範囲で添加することにより、焼結体の電気抵抗を高めて、低い磁気損失を得ることができる。
Na：0.02mass％以下（ただし、０を含まず）
Naは、粒成長を抑制すると共に、結晶粒界に偏析して電気抵抗を高める効果があり、損失の低減に寄与する。上記電気抵抗を高める効果は、後述する酸化物系の添加成分に比べて大きく、添加量にほぼ比例して増加するが、0.02mass％付近でほぼ飽和する。また、Naの添加によって、僅かではあるが焼結密度が低下し、それに伴い、飽和磁束密度も低下する傾向がある。そのため、添加量は低く抑えることが好ましく、0.02mass％を上限とする。なお、損失低減効果を享受すると共に、飽和磁束密度を高く維持する観点からは、Naの好ましい添加範囲は0.0005〜0.015mass％である。
The Mn-Zn-Ni ferrite of the present invention increases the electrical resistance of the sintered body by adding one or two of Na and K in the following ranges in addition to the above basic components and additive components. Thus, a low magnetic loss can be obtained.
Na: 0.02 mass% or less (excluding 0)
Na has the effect of suppressing grain growth and segregating at the grain boundaries to increase electrical resistance, contributing to the reduction of loss. The effect of increasing the electrical resistance is greater than that of an oxide-based additive component described later, and increases substantially in proportion to the amount added, but is substantially saturated around 0.02 mass%. Further, the addition of Na slightly decreases the sintered density, and accordingly, the saturation magnetic flux density tends to decrease. Therefore, it is preferable to keep the addition amount low, and the upper limit is 0.02 mass%. In addition, from the viewpoint of enjoying the loss reduction effect and maintaining a high saturation magnetic flux density, the preferable addition range of Na is 0.0005 to 0.015 mass%.
Ｋ：0.015mass％以下（ただし、０を含まず）
Ｋは、Naと同様に、結晶粒界に偏析して電気抵抗を高める効果がある。その効果は、Naより少ない添加量で発現するが、添加量が多くなると、その効果が減少する。また、Ｋの添加量の増加にしたがい、焼結密度が低下し、飽和磁束密度も低下するため、上限を0.015mass％とする。好ましくは、0.0005〜0.010mass％の範囲である。
K: 0.015 mass% or less (excluding 0)
K, like Na, has the effect of segregating at the grain boundaries and increasing the electrical resistance. The effect is manifested with a smaller additive amount than Na, but the effect decreases as the additive amount increases. Also, as the amount of K added increases, the sintering density decreases and the saturation magnetic flux density also decreases, so the upper limit is made 0.015 mass%. Preferably, it is the range of 0.0005-0.010 mass%.
本発明のMn−Zn−Ni系フェライトは、磁気損失をより小さくするために、上記基本成分および必須添加成分の他にさらに、スピネルに固溶しないTa2Ｏ5，ZrＯ2，Nb2Ｏ5，Ｖ2Ｏ5，HfＯ2，Bi2Ｏ3，MoＯ3やスピネル構成元素として部分的に固溶するTiＯ2およびSnＯ2の中から選ばれる１種または２種以上を、下記の範囲で添加することができる。
Ta2Ｏ5：0.005〜0.1mass％
Ta2Ｏ5は、SiＯ2，CaＯの共存下で比抵抗の増大に寄与するが、含有量が0.005mass％に満たない場合はその添加効果に乏しく、一方、0.1mass％を超えると、逆に磁気損失の増大を招く。したがって、Ta2Ｏ5は、0.005〜0.1mass％の範囲で添加するのが好ましい。
In order to reduce magnetic loss, the Mn-Zn-Ni-based ferrite of the present invention further includes Ta 2 O 5 , ZrO 2 , Nb 2 O 5 which does not dissolve in spinel in addition to the basic component and the essential additive component. , V 2 O 5 , HfO 2 , Bi 2 O 3 , MoO 3 , or one or more selected from among TiO 2 and SnO 2 that are partially solid-solved as spinel constituent elements are added within the following range. can do.
Ta 2 O 5 : 0.005 to 0.1 mass%
Ta 2 O 5 contributes to an increase in specific resistance in the presence of SiO 2 and CaO. However, when the content is less than 0.005 mass%, the effect of addition is poor. This increases the magnetic loss. Therefore, Ta 2 O 5 is preferably added in the range of 0.005 to 0.1 mass%.
ZrＯ2：0.01〜0.15mass％
ZrＯ2は、SiＯ2，CaＯ，Ta2Ｏ5の共存下で、Ta2Ｏ5と同様に、粒界の抵抗を高めて高周波帯域での磁気損失の低減に寄与する。Ta2Ｏ5と比べると、抵抗増加の効果が少ないが、損失低減への寄与は大きく、特に、磁気損失が最小となる温度付近から高温側における損失の低減に有効に寄与する。ZrＯ2含有量が0.01mass％未満では、その効果に乏しく、一方、0.15mass％を超えると、逆に比抵抗を高める効果が飽和し、磁気損失が増大する。よって、ZrＯ2は0.01〜0.15mass％とすることが好ましい。
ZrO 2 : 0.01 to 0.15 mass%
ZrO 2 contributes to the reduction of magnetic loss in the high frequency band by increasing the resistance of the grain boundary in the coexistence of SiO 2 , CaO and Ta 2 O 5 , similarly to Ta 2 O 5 . Compared with Ta 2 O 5 , the effect of increasing the resistance is small, but the contribution to the loss reduction is large. In particular, it effectively contributes to reducing the loss on the high temperature side from near the temperature at which the magnetic loss is minimized. If the ZrO 2 content is less than 0.01 mass%, the effect is poor. On the other hand, if it exceeds 0.15 mass%, the effect of increasing the specific resistance is saturated and the magnetic loss increases. Accordingly, ZrO 2 is preferably a 0.01~0.15mass%.
Nb2Ｏ5：0.005〜0.05mass％
Nb2Ｏ5は、SiＯ2，CaＯと共に粒界相を形成し、粒界抵抗を高めて磁気損失の低減に寄与する。0.005mass％未満ではその効果に乏しく、逆に、0.05mass％を超えると、過剰に粒界相に析出し、磁気損失を増大するので、0.005〜0.05mass％の範囲で添加するのが好ましい。
Nb 2 O 5 : 0.005 to 0.05 mass%
Nb 2 O 5 forms a grain boundary phase together with SiO 2 and CaO, increases the grain boundary resistance, and contributes to the reduction of magnetic loss. If it is less than 0.005 mass%, the effect is poor. Conversely, if it exceeds 0.05 mass%, it excessively precipitates in the grain boundary phase and increases the magnetic loss. Therefore, it is preferably added in the range of 0.005 to 0.05 mass%.
Ｖ2Ｏ5：0.001〜0.05mass％、HfＯ2：0.005〜0.05mass％
Ｖ2Ｏ5，HfＯ2は、ともに異常粒成長を抑制し、粒界抵抗を高める働きがある。少ないとその改善効果がなく、また多すぎると磁気損失が増大するため、Ｖ2Ｏ5は0.001〜0.05mass％、HfＯ2は0.005〜0.05mass％の範囲で添加することが好ましい。
V 2 O 5: 0.001~0.05mass%, HfO 2: 0.005~0.05mass%
V 2 O 5 and HfO 2 both function to suppress abnormal grain growth and increase grain boundary resistance. If the amount is too small, the improvement effect is not obtained. If the amount is too large, the magnetic loss increases. Therefore, it is preferable to add V 2 O 5 in the range of 0.001 to 0.05 mass% and HfO 2 in the range of 0.005 to 0.05 mass%.
Bi2Ｏ3：0.003〜0.03mass％、MoＯ3：0.003〜0.03mass％
Bi2Ｏ3，MoＯ3は、結晶粒内の応力を緩和する働きがあり、磁気損失の低減に寄与する。少ないとその改善効果がなく、また多すぎると磁気損失が増大するため、Bi2Ｏ3は0.003〜0.03mass％、MoＯ3は0.003〜0.03mass％の範囲で添加するのが好ましい。
Bi 2 O 3: 0.003~0.03mass%, MoO 3: 0.003~0.03mass%
Bi 2 O 3 and MoO 3 have a function of relieving stress in crystal grains and contribute to reduction of magnetic loss. If the amount is too small, the improvement effect is not obtained. If the amount is too large, the magnetic loss increases. Therefore, Bi 2 O 3 is preferably added in the range of 0.003 to 0.03 mass%, and MoO 3 is preferably added in the range of 0.003 to 0.03 mass%.
TiＯ2：0.01〜0.3mass％、SnＯ2：0.01〜2.0mass％
TiＯ2，SnＯ2は、スピネル構成元素として部分的に粒内に固溶する成分である。TiＯ2は、一部粒界にも存在し、焼成後の冷却過程で粒界再酸化を助長して磁気損失を低下させる。この効果を得るためには、0.01mass％以上の添加が好ましい。逆に、多すぎると異常粒成長を引き起こすため、0.3mass％以下の範囲で添加することができる。SnＯ2は、損失低減に寄与するためには、0.01mass％以上添加することが好ましく、また、TiＯ2ほど異常粒成長を引き起こさないため、上限は2.0mass％まで添加することができる。
TiO 2: 0.01~0.3mass%, SnO 2 : 0.01~2.0mass%
TiO 2 and SnO 2 are components that partially dissolve in the grains as spinel constituent elements. TiO 2 is also present at some grain boundaries, and promotes grain boundary reoxidation in the cooling process after firing to reduce magnetic loss. In order to obtain this effect, addition of 0.01 mass% or more is preferable. On the contrary, if it is too much, abnormal grain growth is caused, so it can be added in a range of 0.3 mass% or less. SnO 2 is preferably added in an amount of 0.01 mass% or more in order to contribute to loss reduction. Further, since it does not cause abnormal grain growth as much as TiO 2 , the upper limit can be added up to 2.0 mass%.
Mn−Zn−Ni系フェライトの基本成分の最終組成が表１に示した組成となるように、原料酸化物を配合し、ボールミルを用いて湿式混合し、乾燥し、その後、この混合粉を大気雰囲気中で925℃×３時間の仮焼を行ない仮焼粉とした。この仮焼粉に対し、SiＯ2：0.006mass％、CaＣＯ3：0.13mass％、Ｋ2ＣＯ3：0.015mass％、Nb2Ｏ5：0.02mass％を添加し、再度ボールミルを用いて湿式混合して粉砕し、乾燥して得た粉末に、ポリビニルアルコール５mass％水溶液を10mass％加えて造粒し、外径36mm、内径24mm、高さ12mmのリング状に成形した。この成形体を、酸素濃度を８vol％以下に制御した窒素・空気混合ガス中で1370℃×２時間の焼成を行なった。このようにして得られた焼結体試料に、１次側20巻・２次側40巻の巻線を施し、直流ＢＨループトレーサーを用いて、100℃における、1200Ａ／ｍの磁場をかけたときの磁束密度を測定した。なお、上記磁束密度は、この大きさの磁場ではほぼ飽和しており、飽和磁束密度Ｂsと見なせる。また、同じ焼結体試料に、１次側５巻・２次側５巻の巻線を施し、交流ＢＨトレーサーを用いて、100℃における、周波数100ｋＨz、最大磁束密度200ｍＴの電力損失Ｐcvを測定した。 The raw material oxides are blended so that the final composition of the basic components of the Mn-Zn-Ni-based ferrite is the composition shown in Table 1, wet-mixed using a ball mill, dried, and then the mixed powder is removed from the atmosphere. Calcination was performed in an atmosphere at 925 ° C. for 3 hours to obtain a calcined powder. To this calcined powder, SiO 2: 0.006mass%, CaCO 3: 0.13mass%, K 2 CO 3: 0.015mass%, Nb 2 O 5: addition of 0.02 mass%, and wet-mixed using a ball mill again The powder obtained by pulverizing and drying was added with 10% by mass of a 5% by weight aqueous solution of polyvinyl alcohol and granulated to form a ring having an outer diameter of 36 mm, an inner diameter of 24 mm and a height of 12 mm. This molded body was fired at 1370 ° C. for 2 hours in a nitrogen / air mixed gas in which the oxygen concentration was controlled to 8 vol% or less. The sintered body sample thus obtained was wound with 20 turns on the primary side and 40 turns on the secondary side, and a magnetic field of 1200 A / m at 100 ° C. was applied using a DC BH loop tracer. The magnetic flux density was measured. The magnetic flux density is almost saturated with a magnetic field of this magnitude, and can be regarded as the saturation magnetic flux density Bs. The same sintered body sample was wound with 5 turns on the primary side and 5 turns on the secondary side, and an AC BH tracer was used to measure the power loss Pcv with a frequency of 100 kHz and a maximum magnetic flux density of 200 mT at 100 ° C. did.
上記磁束密度および電力損失の測定結果を表１中に併記して示した。この表から、本発明の基本成分に適合した実施例(No.１〜８)では、480ｍＴを超える飽和磁束密度と900ｋＷ／ｍ3以下の低い損失を兼ね備えたフェライトが得られることがわかる。 The measurement results of the magnetic flux density and power loss are shown together in Table 1. From this table, it can be seen that in Examples (Nos. 1 to 8) adapted to the basic components of the present invention, ferrite having a saturation magnetic flux density exceeding 480 mT and a low loss of 900 kW / m 3 or less can be obtained.
Mn−Zn−Ni系フェライトの基本成分が、最終組成としてFe2Ｏ3：MnＯ：ZnＯ：NiＯが61.6：20.2：12.8：5.4のモル比を有するよう調整した仮焼粉を、実施例１と同様にして作製した。この仮焼粉に対し、SiＯ2：0.009mass％、CaＣＯ3：0.1mass％、Ta2Ｏ5：0.035mass％、ZrＯ2：0.02mass％を添加し、さらに、Na2ＣＯ3，Ｋ2ＣＯ3を、添加量を０〜0.025mass％近傍までの範囲で変化させて添加し、湿式粉砕して得た粉砕粉を、実施例１と同様にして、造粒、成形した後、酸素濃度を８vol％以下に制御した窒素・空気混合ガス中で1370℃×２時間の焼成を行った。 The calcined powder in which the basic component of the Mn-Zn-Ni-based ferrite was adjusted so that the final composition Fe 2 O 3 : MnO: ZnO: NiO had a molar ratio of 61.6: 20.2: 12.8: 5.4 It produced similarly. To this calcined powder, SiO 2: 0.009mass%, CaCO 3: 0.1mass%, Ta 2 O 5: 0.035mass%, ZrO 2: addition of 0.02 mass%, further, Na 2 CO 3, K 2 CO 3 was added with the addition amount changed in the range of 0 to 0.025 mass%, and the pulverized powder obtained by wet pulverization was granulated and molded in the same manner as in Example 1, and then the oxygen concentration was adjusted. Firing was performed at 1370 ° C. for 2 hours in a nitrogen / air mixed gas controlled to 8 vol% or less.
このようにして得られた焼結体試料について、実施例１と同様の条件で、磁束密度と磁気損失を測定した。また、電気抵抗率ρ(Ω・cm)を４端子法で測定した。それらの結果を、Na，Ｋの添加量との関係で整理し、図１〜３に示した。これらの図から、Na，Ｋの添加量が、本発明の範囲にある場合には、損失が低いMn−Zn−Ni系フェライトが得られることがわかる。 The sintered compact sample thus obtained was measured for magnetic flux density and magnetic loss under the same conditions as in Example 1. In addition, the electrical resistivity ρ (Ω · cm) was measured by a four-terminal method. The results are arranged in relation to the amounts of Na and K added and are shown in FIGS. From these figures, it can be seen that when the added amounts of Na and K are within the range of the present invention, Mn—Zn—Ni ferrite with low loss can be obtained.
Mn−Zn−Ni系フェライトの基本成分が、最終組成としてFe2Ｏ3：MnＯ：ZnＯ：NiＯが60.8：20.4：13.6：5.2のモル比を有するよう調整した仮焼粉を、実施例１と同様にして作製し、この仮焼粉に、添加成分として、表２および表３に示した各種酸化物を添加して粉砕し、成形したものを、酸素濃度を10vol％以下に制御した窒素・空気混合ガス中で1230〜1380℃×２〜６時間の焼成を行なった。このようにして得られた焼結体試料を、実施例１と同様の条件で、磁束密度および磁気損失を測定し、これらの測定結果を表２および表３に併記して示した。表２および表３から、添加成分の添加量が本発明の範囲である場合には、飽和磁束密度が高くかつ比較的損失が低いMn−Zn−Ni系フェライトが得られているのに対し、添加量が、本発明から外れているものは、いずれも磁気損失が大きくなっていることがわかる。 The calcined powder in which the basic component of the Mn-Zn-Ni ferrite was adjusted so that the final composition Fe 2 O 3 : MnO: ZnO: NiO had a molar ratio of 60.8: 20.4: 13.6: 5.2 In the same manner, this calcined powder was added with various oxides shown in Table 2 and Table 3 as an additive component, pulverized, and molded into nitrogen / oxygen whose oxygen concentration was controlled to 10 vol% or less. Firing was performed in an air mixed gas at 1230 to 1380 ° C. for 2 to 6 hours. The sintered compact sample thus obtained was measured for magnetic flux density and magnetic loss under the same conditions as in Example 1. The measurement results are shown in Tables 2 and 3 together. From Table 2 and Table 3, when the addition amount of the additive component is within the range of the present invention, an Mn-Zn-Ni ferrite having a high saturation magnetic flux density and a relatively low loss is obtained. It can be seen that the magnetic loss increases in any case where the addition amount is out of the present invention.
本発明の技術は、大電流を流すことが要求されるチョークコイルにも適用することができる。 The technique of the present invention can also be applied to a choke coil that is required to pass a large current.
Claims (2)
記
Ta2Ｏ5：0.005〜0.1mass％
ZrＯ2：0.01〜0.15mass％
Nb2Ｏ5：0.005〜0.05mass％
Ｖ2Ｏ5：0.001〜0.05mass％
HfＯ2：0.005〜0.05mass％
Bi2Ｏ3：0.003〜0.03mass％
MoＯ3：0.003〜0.03mass％
TiＯ2：0.01〜0.3mass％
SnＯ2：0.01〜2.0mass％ Basic component, Fe 2 O 3: 58~64mol% , ZnO: 8~14mol%, NiO: 3~8mol%, balance being substantially MnO, as an additive component SiO 2: 0.005~0.05mass% and CaO : In Mn-Zn-Ni ferrite containing 0.02 to 0.2 mass%, Na: 0.02 mass% or less (not including 0), K: 0.015 mass% or less (not including 0) or 2 Contains a total of 0.02 mass% or less of seeds, and further selected from Ta 2 O 5 , ZrO 2 , Nb 2 O 5 , V 2 O 5 , HfO 2 , Bi 2 O 3 , MoO 3 , TiO 2 and SnO 2 A high saturation magnetic flux density Mn-Zn-Ni-based ferrite containing one or more of the above in the following range.
Record
Ta 2 O 5 : 0.005 to 0.1 mass%
ZrO 2 : 0.01 to 0.15 mass%
Nb 2 O 5 : 0.005 to 0.05 mass%
V 2 O 5: 0.001~0.05mass%
HfO 2 : 0.005 to 0.05 mass%
Bi 2 O 3 : 0.003 to 0.03 mass%
MoO 3 : 0.003 ~ 0.03mass%
TiO 2: 0.01~0.3mass%
SnO 2 : 0.01 to 2.0 mass%
2. The high saturation magnetic flux density Mn—Zn—Ni ferrite according to claim 1, wherein the saturation magnetic flux density at 100 ° C. is 480 mT or more, the magnetic loss at 100 kHz, and 200 mT is 900 kW / m 3 or less.
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| JP2011017767A (en) * | 2009-07-07 | 2011-01-27 | Konica Minolta Business Technologies Inc | Fixing device and image forming apparatus, as well as, heating element |
| JP2012246154A (en) * | 2011-05-25 | 2012-12-13 | Tdk Corp | Ferrite composition and electronic part |
| JP2015023275A (en) * | 2013-07-19 | 2015-02-02 | サムソン エレクトロ−メカニックス カンパニーリミテッド． | Ferrite and inductor including the same |
| US10236104B2 (en) | 2013-07-19 | 2019-03-19 | Samsung Electro-Mechanics Co., Ltd. | Ferrite and inductor including the same |
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| CN107200574B (en) * | 2017-05-12 | 2021-01-01 | 天长市中德电子有限公司 | Low-loss soft magnetic ferrite material |
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| JPH0653023A (en) * | 1992-01-14 | 1994-02-25 | Matsushita Electric Ind Co Ltd | Oxide magnetic material |
| JP2000306717A (en) * | 1999-04-21 | 2000-11-02 | Fuji Elelctrochem Co Ltd | Low-loss oxide magnetic material |
| JP2004161593A (en) * | 2002-09-26 | 2004-06-10 | Tdk Corp | Ferritic material |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2011017767A (en) * | 2009-07-07 | 2011-01-27 | Konica Minolta Business Technologies Inc | Fixing device and image forming apparatus, as well as, heating element |
| JP2012246154A (en) * | 2011-05-25 | 2012-12-13 | Tdk Corp | Ferrite composition and electronic part |
| JP2015023275A (en) * | 2013-07-19 | 2015-02-02 | サムソン エレクトロ−メカニックス カンパニーリミテッド． | Ferrite and inductor including the same |
| US10236104B2 (en) | 2013-07-19 | 2019-03-19 | Samsung Electro-Mechanics Co., Ltd. | Ferrite and inductor including the same |
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