JP5093790B2 - Mn-Zn ferrite and method for producing the same - Google Patents
Mn-Zn ferrite and method for producing the same Download PDFInfo
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Description
本発明は、駆動周波数が数十ｋＨz以上のスイッチング電源のコイル磁心等として好適に用いられるMn−Zn系フェライトに関するものである。 The present invention relates to an Mn-Zn ferrite suitably used as a coil magnetic core or the like of a switching power supply having a driving frequency of several tens of kHz or more.
スイッチング電源は、電圧変換や電気的絶縁機能のほか、不要なノイズを除去し、安定して電圧を供給するといった複数の機能を有する重要な部品である。上記機能を得るために、スイッチング電源に搭載されているトランスやノイズフィルター、チョークコイル等の巻線部品には各種のフェライトコアが用いられており、その用途に応じて適切な特性のフェライトコアが選択されている。例えば、トランス用磁心のフェライトコアとしては、電力損失(コアロス)が小さく、温度変化に対する電力損失の変動が小さいものが用いられている。 The switching power supply is an important component having a plurality of functions such as voltage conversion and electrical insulation functions, as well as removal of unnecessary noise and stable supply of voltage. In order to obtain the above functions, various ferrite cores are used for winding components such as transformers, noise filters, and choke coils mounted on switching power supplies. Is selected. For example, as a ferrite core of a transformer core, one having a small power loss (core loss) and a small variation in power loss with respect to a temperature change is used.
一方、フェライトコアの製造性や輸送中のハンドリング性を改善し、さらにコアへのボビン装着性や、装着したボビンへの巻線の作業性を高めるには、フェライトコアの機械的強度が高いことが求められる。中でも衝撃によるフェライトコアの欠損(欠け)が生じ難いこと、即ち、欠け強度が高いことが重要である。それは、製造過程でのフェライトコア同士の衝突やフェライトコアと加工治具、加工工具などとの衝突により発生する欠けは、製品としての特性を劣化させるだけでなく、欠けた部分の鋭利なエッジによって、巻きつけたコイルの被覆が破れたり、あるいは、導電性のフェライトの欠け屑がスイッチング電源内部の回路に混入して絶縁破壊を引き起こしたりして、製品品質への信頼性を大きく低下させる原因となるからである。 On the other hand, in order to improve the manufacturability of ferrite cores and handling during transportation, and to improve the workability of bobbin mounting to the core and the winding workability to the installed bobbin, the ferrite core must have high mechanical strength. Is required. In particular, it is important that the ferrite core is not easily damaged (chip) due to impact, that is, the chip strength is high. This is because chipping caused by collisions between ferrite cores in the manufacturing process and collisions between ferrite cores and processing jigs, processing tools, etc. not only deteriorates the product characteristics but also due to the sharp edges of the chipped parts. The reason is that the coating of the wound coil is broken, or the chip of conductive ferrite is mixed into the circuit inside the switching power supply and causes dielectric breakdown. Because it becomes.
低い電力損失を実現するＭｎ−Ｚｎ系フェライトとしては、例えば、特許文献１には、ＳｉＯ２，ＣａＯ，Ｔａ２Ｏ５およびＴｉＯ２を同時に添加したものが提案されている。しかし、このフェライトは、低損失を実現してはいるものの、損失の温度変化が大きく欠け強度に劣るという問題がある。この問題に対して、例えば、特許文献２には、Ｍｎ−Ｚｎ系フェライトにＣｏイオンを含有させ、これにＴａ２Ｏ５やＺｒＯ２を添加することにより、損失と温度特性の改善を図る技術が、また、特許文献３には、Ｃｏイオンを含むＭｎ−Ｚｎ系フェライトに、さらにＮｂ２Ｏ５やＺｒＯ２を添加することにより、損失の温度変化を抑制する技術が開示されている。
特許文献２や３の技術によれば、確かに電力損失が低くかつ損失の温度変化が小さいフェライトを得ることができる。しかし、これらの技術で得られるフェライトコアは、欠け強度が必ずしも十分ではない。すなわち、従来技術では、電力損失が低くて温度変化が小さく、しかも欠け強度に優れるMn−Zn系フェライトは実現できていなかった。 According to the techniques of Patent Documents 2 and 3, it is possible to obtain a ferrite with a low power loss and a small temperature change of the loss. However, the ferrite core obtained by these techniques does not necessarily have sufficient chipping strength. That is, in the prior art, an Mn-Zn ferrite having low power loss, small temperature change, and excellent chipping strength has not been realized.
本発明の目的は、電力損失が低くて、その温度変化が小さくしかも欠け強度にも優れるMn−Zn系フェライトコアとその製造方法を提案することにある。 An object of the present invention is to propose an Mn—Zn ferrite core having low power loss, small temperature change and excellent chipping strength, and a method for manufacturing the same.
発明者らは、上記問題点を解決するために鋭意調査研究を重ねた。その結果、電力損失が低くて、その温度変化が小さくしかも欠け強度にも優れるMn−Zn系フェライトコアを得るためには、フェライト原料である造粒粉の主成分および微量成分をそれぞれ適正範囲に制御すると共に、製造工程、特に成形工程における条件制御が特に重要であることを見出し、本発明を完成するに至った。 Inventors repeated earnest investigation research in order to solve the said problem. As a result, in order to obtain a Mn-Zn ferrite core with low power loss, small temperature change and excellent chipping strength, the main component and trace component of the granulated powder, which is a raw material of ferrite, are set within appropriate ranges. In addition to controlling, it was found that condition control in the manufacturing process, particularly the molding process, is particularly important, and the present invention has been completed.
すなわち、本発明は、Ｆｅ２Ｏ３，ＭｎＯ，ＺｎＯおよびＣｏＯを主成分とするＭｎ−Ｚｎ系フェライトにおいて、その主成分の組成がＦｅ２Ｏ３：５１〜５６ｍｏｌ％、ＺｎＯ：６〜１４ｍｏｌ％、ＣｏＯ：０．０５〜０．４ｍｏｌ％、残部ＭｎＯからなり、さらに、内数として含有する微量元素が、酸化物換算でＳｉＯ２：０．００５〜０．０５ｍａｓｓ％、ＣａＯ：０．０２〜０．２ｍａｓｓ％、Ｎｂ２Ｏ５：０．００５〜０．０５ｍａｓｓ％、ＴｉＯ２：０．０１〜０．５ｍａｓｓ％からなる成分組成を有すると共に、ＪＰＭＡ Ｐ１１に準拠して欠け試験を行ったときの下記式；
Ｓ＝｛（Ａ−Ｂ）／Ａ｝×１００（％）
ただし、Ａ：試験前の５試料の総重量（ｇ）
Ｂ：試験後の５試料の破片を除く総重量（ｇ）
で定義される欠損率Ｓが２．０％以下の特性を示すことを特徴とするＭｎ−Ｚｎ系フェライトである。
That is, according to the present invention, in a Mn—Zn-based ferrite containing Fe 2 O 3 , MnO, ZnO and CoO as main components, the composition of the main components is Fe 2 O 3 : 51 to 56 mol%, ZnO: 6 to 14 mol%. , CoO: 0.05~0.4mol%, the balance being MnO, further trace elements contained as internal numbers, SiO terms of oxide 2: 0.005~0.05mass%, CaO: 0.02~ 0.2mass%, Nb 2 O 5: 0.005~0.05mass%, TiO 2: and has a chemical composition consisting 0.01~0.5mass%, when subjected to chipping test according to JPMA P11 The following formula:
S = {(A−B) / A} × 100 (%)
However, A: Total weight (g) of 5 samples before the test
B: Total weight (g) excluding debris of 5 samples after the test
The Mn—Zn-based ferrite is characterized in that the defect rate S defined by the above has a characteristic of 2.0% or less.
また、本発明は、Ｆｅ２Ｏ３，ＭｎＯ，ＺｎＯおよびＣｏＯを主成分とし、その主成分の組成がＦｅ２Ｏ３：５１〜５６ｍｏｌ％、ＺｎＯ：６〜１４ｍｏｌ％、ＣｏＯ：０．０５〜０．４ｍｏｌ％、残部ＭｎＯからなり、さらに、内数として含有する微量元素が、酸化物換算でＳｉＯ２：０．００５〜０．０５ｍａｓｓ％、ＣａＯ：０．０２〜０．２ｍａｓｓ％、Ｎｂ２Ｏ５：０．００５〜０．０５ｍａｓｓ％、ＴｉＯ２：０．０１〜０．５ｍａｓｓ％からなる成分組成を有する造粒粉を、金型を用いて成形し、焼成してＭｎ−Ｚｎ系フェライトを製造する際、成形時における上記造粒粉の温度を４５〜１００℃とし、水分率を０．０１〜１０ｍａｓｓ％とすると共に、成形用の金型の粉末が接触する部位の温度を４５〜１００℃に制御し、欠損率Ｓが２．０％以下となる温度で焼成することを特徴とするＭｎ−Ｚｎ系フェライトの製造方法を提案する。 Further, the present invention mainly comprises Fe 2 O 3 , MnO, ZnO and CoO, and the composition of the main components is Fe 2 O 3 : 51 to 56 mol%, ZnO: 6 to 14 mol%, CoO: 0.05 to It consists of 0.4 mol% and the balance MnO, and the trace elements contained as internal numbers are SiO 2 : 0.005-0.05 mass%, CaO: 0.02-0.2 mass%, Nb 2 in terms of oxide. A granulated powder having a component composition consisting of O 5 : 0.005 to 0.05 mass% and TiO 2 : 0.01 to 0.5 mass% is molded using a mold, fired, and Mn—Zn ferrite. When the temperature of the granulated powder at the time of molding is 45 to 100 ° C., the moisture content is 0.01 to 10 mass%, and the temperature of the part where the molding die powder contacts is 45 to 45%. 100 ° C And a method for producing a Mn—Zn-based ferrite, characterized by firing at a temperature at which the defect rate S is 2.0% or less .
本発明によれば、電力損失が低くて、その温度変化が小さく、しかも製造工程中における欠けが起こり難いＭｎ−Ｚｎ系フェライトコアを得ることができるので、スイッチング電源などの小型化や高性能化、信頼性向上に大いに寄与する。 According to the present invention, have low power losses, reduced its temperature changes, and since it is possible to obtain the missing occurs hardly Mn-Zn ferrite core in the manufacturing process, compact such as a switching power supply and high It greatly contributes to performance improvement and reliability improvement.
Ｍｎ−Ｚｎ系フェライトの成分組成を、上記範囲に制限する理由について説明する。
Ｆｅ２Ｏ３：５１〜５６ｍｏｌ％、ＺｎＯ：６〜１４ｍｏｌ％、ＣｏＯ：０．０５〜０．４ｍｏｌ％および残部：ＭｎＯ
本発明のＭｎ−Ｚｎ系フェライトは、Ｆｅ２Ｏ３，ＺｎＯ，ＣｏＯおよびＭｎＯを主成分とするものであり、それら主成分の組成が適切な範囲を外れると、損失が上昇したり、損失の温度変化が過大になったりする。そのため、Ｆｅ２Ｏ３：５１〜５６ｍｏｌ％、ＺｎＯ：６〜１４ｍｏｌ％、ＣｏＯ：０．０５〜０．４ｍｏｌ％、残部：ＭｎＯの範囲に制御する必要がある。
The reason why the component composition of the Mn—Zn ferrite is limited to the above range will be described.
Fe 2 O 3: 51~56mol%, ZnO: 6~14mol%, CoO: 0.05~ 0.4 mol% and the balance: MnO
The Mn—Zn-based ferrite of the present invention is composed mainly of Fe 2 O 3 , ZnO, CoO and MnO. If the composition of these main components is outside the appropriate range, the loss increases or the loss increases. The temperature change becomes excessive. Therefore, Fe 2 O 3: 51~56mol% , ZnO: 6~14mol%, CoO: 0.05~ 0.4 mol%, the balance has to be controlled in the range of MnO.
本発明のMn−Zn系フェライトにおいては、上述した主成分の他に、SiＯ2，CaＯ，Nb2Ｏ5およびTiＯ2からなる微量成分を、下記の組成範囲(内数)で含有することが重要である。
SiＯ2：0.005〜0.05mass％、CaＯ：0.02〜0.2mass％
SiＯ2およびCaＯは、Mn−Zn系フェライトの比抵抗を上昇させ、損失を低下させるために添加する成分である。これらの成分の添加量が少なすぎる場合は、上記効果が得られず、一方、過剰に添加した場合には、焼成した際に異常粒成長が起こったり、結晶粒成長が過剰に阻害されたりして損失が上昇する。よって、それぞれの添加量は、SiＯ2：0.005〜0.05mass％、CaＯ：0.02〜0.2mass％の範囲に制限する必要がある。
In the Mn-Zn ferrite of the present invention, in addition to the main components described above, a trace component composed of SiO 2 , CaO, Nb 2 O 5 and TiO 2 may be contained in the following composition range (inner number). is important.
SiO 2: 0.005~0.05mass%, CaO: 0.02~0.2mass%
SiO 2 and CaO raises the resistivity of Mn-Zn ferrite, a component added to reduce the loss. If the amount of these components added is too small, the above effect cannot be obtained. On the other hand, if added excessively, abnormal grain growth may occur during firing, or crystal grain growth may be excessively inhibited. Loss increases. Thus, each addition amount, SiO 2: 0.005~0.05mass%, CaO : it is necessary to limit the range of 0.02~0.2mass%.
Nb2Ｏ5：0.005〜0.05mass％
Nb2Ｏ5は、比抵抗を高め損失を低減する効果を有することが知られているが、本発明は、その他に、欠け強度を改善する効果があることも見出した。Nb2Ｏ5の添加量が少なすぎる場合には、上記効果の発現が不十分であり、一方、過剰に添加すると、却って損失上昇や強度低下を引き起こす。よって、Nb2Ｏ5は0.005〜0.05mass％の範囲に限定する。
Nb 2 O 5 : 0.005 to 0.05 mass%
Nb 2 O 5 is known to have an effect of increasing specific resistance and reducing loss, but the present invention has also found that it has an effect of improving chipping strength. When the amount of Nb 2 O 5 added is too small, the above effect is not sufficiently exhibited. On the other hand, when it is excessively added, loss increases and strength decreases. Thus, Nb 2 O 5 is limited to the range of 0.005~0.05mass%.
TiＯ2：0.01〜0.5mass％
TiＯ2は、従来、比抵抗を上昇させることが知られているが、本発明では、欠け強度をさらに改善するために添加する。すなわち、TiＯ2は、CoＯを含有する本発明のMn−Zn系フェライトにおいては、従来報告されているような特段の損失低減効果は認められない。一方、欠け強度は、先述したNb2Ｏ5の添加によりある程度改善されるが、その効果は不十分である。ここで、Nb2Ｏ5の添加と同時にTiＯ2を添加すると、欠け強度がさらに改善されることがわかった。しかし、添加量が過剰となった場合には、逆に、欠け強度の低下や電力損失の上昇が起こる。よって、TiＯ2の添加量は0.01〜0.5mass％の範囲とする。
TiO 2: 0.01~0.5mass%
TiO 2 is conventionally known to increase the specific resistance, but in the present invention, it is added to further improve the chip strength. That is, TiO 2 does not have a particular loss reduction effect as reported in the Mn-Zn ferrite of the present invention containing CoO. On the other hand, the chipping strength is improved to some extent by the addition of Nb 2 O 5 described above, but the effect is insufficient. Here, it was found that when TiO 2 was added simultaneously with the addition of Nb 2 O 5 , the chipping strength was further improved. However, when the addition amount is excessive, conversely, the chipping strength is reduced and the power loss is increased. Therefore, the amount of TiO 2 added is in the range of 0.01 to 0.5 mass%.
なお、CoＯを含有するMn−Zn系フェライトの低鉄損化は、Ta2Ｏ5やZrＯ2を添加することによっても可能である。しかし、これらの成分の添加は、欠け強度の急激な劣化をもたらすため、本発明の開発目的に対しては不適当である。 Note that the iron loss of Mn—Zn ferrite containing CoO can be reduced by adding Ta 2 O 5 or ZrO 2 . However, the addition of these components brings about a rapid deterioration of the chipping strength and is therefore unsuitable for the purpose of development of the present invention.
上記のような微量成分の添加による欠け強度の改善は、結晶粒や結晶粒界における原子間結合力や残留応力などが、ｎm〜μmのレベルで変化することによるものと考えられる。しかし、本発明が目的とする、より欠け強度に優れた焼結体を得るためには、このような微視的な制御だけでは不十分であり、その他に、フェライト焼結体中に残留するμm〜mmレベルの大きさを有する空孔等の欠陥の存在状態を適正化することが不可欠であり、そのためには、フェライト原料である造粒粉を成形する際の加工条件を適正範囲に制御する必要がある。 It is considered that the improvement of the chipping strength by the addition of the above-described trace components is due to the fact that the interatomic bonding force and residual stress at the crystal grains and grain boundaries change at a level of nm to μm. However, in order to obtain a sintered body excellent in chipping strength, which is an object of the present invention, such microscopic control alone is not sufficient, and in addition, it remains in the ferrite sintered body. It is indispensable to optimize the presence of defects such as vacancies with a size of μm to mm, and for that purpose, the processing conditions when forming granulated powder, which is a raw material for ferrite, are controlled within an appropriate range. There is a need to.
すなわち、低損失のMn−Zn系フェライトを得るためには、フェライトを焼結した後に残留する空孔が少なくて焼結密度が高く、結晶粒径が適度な大きさに制御されていることが望ましい。そして、このような結晶組織を得るために、従来、例えば、焼成温度を1150〜1400℃の範囲としたり、昇温過程の900℃以上における昇温速度を適正範囲に制御したりすることが行われている。しかし、焼成するフェライト成形体自体の内部構造が不均質だと、巨大な空孔が残留したり焼結密度の上昇が妨げられたりして、均一な結晶粒成長が阻害され、あるいは、焼結体の内部と表層とで焼結密度や結晶粒径に差異を生じて、不均質な焼結体組織が形成される。このように不均質な結晶組織は、電力損失の上昇を招いたり、欠け強度の低下を引き起こしたりする。本発明は、以上の観点から検討を重ねた結果、フェライトの成分組成の制御に加えて、成形工程に関わるいくつかのパラメータを適正範囲に制御することによって初めて磁気特性と機械的特性とに優れたフェライトコアを得ることができることを見出し、完成させたものである。 In other words, in order to obtain a low-loss Mn-Zn-based ferrite, it is necessary to control the crystal grain size to an appropriate size with few vacancies remaining after sintering the ferrite, a high sintering density. desirable. In order to obtain such a crystal structure, conventionally, for example, the firing temperature is set to a range of 1150 to 1400 ° C., or the temperature increase rate at 900 ° C. or higher in the temperature increase process is controlled to an appropriate range. It has been broken. However, if the internal structure of the ferrite compact to be fired itself is inhomogeneous, huge voids remain or the increase in the sintering density is hindered, thereby inhibiting uniform grain growth or sintering. A difference occurs in the sintered density and crystal grain size between the inside of the body and the surface layer, and a heterogeneous sintered body structure is formed. Such a heterogeneous crystal structure causes an increase in power loss or a decrease in chipping strength. As a result of repeated examinations from the above viewpoint, the present invention is excellent in magnetic properties and mechanical properties only by controlling some parameters related to the molding process within an appropriate range in addition to controlling the composition of ferrite. And found that a ferrite core can be obtained.
一般に、粉末冶金法によりMn−Zn系フェライトコアを製造する成形工程では、成形用の金型に充填したフェライトの原料粉末を加圧し、成形することが行われている。ここで上記フェライトの原料粉末とは、粒径が１μm前後の一次粒子を適度に凝集させた形態の造粒粉と呼ばれるもので、流動性を向上し成形体の強度を高めるために、ＰＶＡ(ポリビニルアルコール)などの結合剤(バインダ)や、多少の水分等を含有させたものである。 In general, in a molding process for producing an Mn-Zn ferrite core by a powder metallurgy method, a ferrite raw material powder filled in a molding die is pressed and molded. Here, the ferrite raw material powder is called granulated powder in a form in which primary particles having a particle size of about 1 μm are appropriately aggregated. In order to improve fluidity and increase the strength of the molded body, PVA ( A binder (binder) such as (polyvinyl alcohol) and some moisture.
本発明は、フェライトの原料となる粉末（造粒粉）の成分組成を適正範囲に制御した上で、この造粒粉を金型を用いて成形する際の、造粒粉の温度、造粒粉が含有する水分量（水分率）および造粒粉が接触する金型面の温度を適正な範囲に制御すれば、優れた磁気特性と欠け強度を有するフェライトコアが得られることを見出したところに特徴がある。具体的には、フェライトの造粒粉に上述した適正量のＮｂ２Ｏ５とＴｉＯ２を含有させるとともに、造粒粉の温度を４０〜１００℃、水分率を０．０１〜１０ｍａｓｓ％の範囲に制御し、さらに、金型の粉末が接触する部位の温度を４０〜１００℃に制御することにより、磁気特性と欠け強度とが共に優れるフェライト焼結体を得ることができる。一方、造粒粉の温度、水分率および金型の温度が上記適正範囲から外れると、電力損失と欠け強度のいずれか一方、あるいは両方の特性が劣るものとなる。好ましくは、水分率は０．０１〜１ｍａｓｓ％である。 The present invention controls the component composition of the powder (granulated powder) used as a raw material for ferrite within an appropriate range, and then forms the temperature of the granulated powder and granulation when the granulated powder is molded using a mold. We have found that ferrite cores with excellent magnetic properties and chipping strength can be obtained by controlling the amount of moisture contained in the powder (water content) and the temperature of the mold surface with which the granulated powder comes into contact within an appropriate range. There is a feature. Specifically, the ferrite granulated powder contains the appropriate amounts of Nb 2 O 5 and TiO 2 described above, the temperature of the granulated powder is in the range of 40 to 100 ° C., and the moisture content is in the range of 0.01 to 10 mass%. In addition, by controlling the temperature of the portion where the powder of the mold contacts to 40 to 100 ° C., a ferrite sintered body having both excellent magnetic properties and chipping strength can be obtained. On the other hand, if the temperature of the granulated powder, the moisture content, and the temperature of the mold are out of the appropriate ranges, either the power loss, the chip strength, or both of the characteristics will be inferior. Preferably , the moisture content is 0.01 to 1 mass % .
一般に、優れた磁気特性と機械的特性を得るためには、成形体の均質性が高いほど好ましい。そのような成形体を得るためには、成形体の原料となる造粒粉の流動性が高く、かつ、金型への充填から始まり金型から抜き出す脱型までの成形加工の全工程に亘って金型と造粒粉間に作用する摩擦力は小さい方が好ましい。この観点から考えると、造粒粉の温度や水分率は、粉体間の凝集力や成形加圧時の流動性、造粒粉の塑性変形性等に影響を及ぼし、一方、金型接触面の温度は、粉体と金型間の付着力等に影響を及ぼすことを通じて、造粒粉の成形性が改善され、摩擦力が減少して上記の効果が得られたものと考えられる。 Generally, in order to obtain excellent magnetic properties and mechanical properties, the higher the homogeneity of the molded body, the better. In order to obtain such a molded body, the granulated powder as a raw material of the molded body has a high fluidity, and all steps of the molding process from filling into the mold to demolding are performed. It is preferable that the frictional force acting between the mold and the granulated powder is small. From this point of view, the temperature and moisture content of the granulated powder affect the cohesive force between the powders, the fluidity at the time of molding pressure, the plastic deformability of the granulated powder, etc. It is considered that the above-described temperature has an effect on the adhesive force between the powder and the mold, thereby improving the formability of the granulated powder and reducing the frictional force to obtain the above effect.
なお、成形条件を上記適正範囲に制御する具体的な方法としては、造粒粉の温度制御は、貯粉槽内での温風や冷風による加熱・冷却、粉体供給ラインでの電熱線等による加熱や冷水等による直接あるいは間接冷却により行うことができる。また、造粒粉の水分率の制御は、造粒粉の原料となるフェライト粉砕粉スラリーの水分制御や、造粒粉への加湿と乾燥操作を適宜組み合わせることにより行うことができる。なお、水分率は、加熱式水分率計や熱重量分析装置などで測定することができる。また、造粒粉が接触する部位の金型温度は、当該部位近傍に熱電対を埋め込んで測定する方法が簡便であり、その温度制御は、電熱線、温水、温風、赤外線等による加熱や、ペルチェ素子、冷水、冷風等による冷却を適宜組み合わせることにより行うことができる。 In addition, as a specific method for controlling the molding conditions within the appropriate range, the temperature control of the granulated powder is performed by heating / cooling with hot or cold air in the powder storage tank, heating wire in the powder supply line, etc. The heating can be carried out by direct or indirect cooling with cold water or the like. The moisture content of the granulated powder can be controlled by appropriately combining the moisture control of the ferrite pulverized powder slurry, which is the raw material of the granulated powder, and the humidification and drying operation of the granulated powder. The moisture content can be measured with a heating moisture meter or a thermogravimetric analyzer. In addition, the mold temperature of the part where the granulated powder comes into contact is easily measured by embedding a thermocouple in the vicinity of the part, and the temperature control can be performed by heating with heating wire, hot water, hot air, infrared rays, etc. Further, it can be performed by appropriately combining cooling with a Peltier element, cold water, cold air or the like.
Mn−Zn系フェライトの主成分であるFe2Ｏ3、ZnＯ、CoＯおよびMnＯの組成が、最終的に表１に示した値となるように、酸化鉄、酸化マンガン、酸化亜鉛、酸化コバルトの原料粉末を湿式混合し、乾燥し、950℃で仮焼し、仮焼粉とした。この仮焼粉に、微量成分を、SiＯ2、CaCＯ3、Nb2Ｏ5およびTiＯ2換算で最終的に表１に示した組成(内数)となるよう添加し、ボールミルで12時間の湿式粉砕を行い、その後、バインダとしてＰＶＡ(ポリビニルアルコール)を0.6mass％となるよう添加して、各種の成分組成を有する造粒粉を得た。これらの造粒粉の温度は50±５℃、造粒粉の水分含有量は0.1±0.02mass％であった。その後、これらの造粒粉を、造粒粉が接触する部位の温度を45℃に保持した成形用金型を用いて、外径31mm、内径19mm、高さ７mmのリング型のコアに成形し、この成形体を、最高温度を1350℃、最高温度での保持時間を２時間とする条件で焼成を行い、フェライトコア焼結体とした。 The composition of Fe 2 O 3 , ZnO, CoO and MnO, which are the main components of the Mn-Zn ferrite, finally becomes the values shown in Table 1 so that iron oxide, manganese oxide, zinc oxide, and cobalt oxide The raw material powder was wet mixed, dried and calcined at 950 ° C. to obtain a calcined powder. To this calcined powder, trace components are added so as to finally have the composition (inner number) shown in Table 1 in terms of SiO 2 , CaCO 3 , Nb 2 O 5 and TiO 2, and wet for 12 hours with a ball mill. After pulverization, PVA (polyvinyl alcohol) was added as a binder so as to be 0.6 mass% to obtain granulated powder having various component compositions. The temperature of these granulated powders was 50 ± 5 ° C., and the water content of the granulated powder was 0.1 ± 0.02 mass%. Thereafter, these granulated powders are molded into a ring-shaped core having an outer diameter of 31 mm, an inner diameter of 19 mm, and a height of 7 mm using a molding die in which the temperature of the part where the granulated powder contacts is maintained at 45 ° C. The molded body was fired under the conditions of a maximum temperature of 1350 ° C. and a holding time at the maximum temperature of 2 hours to obtain a ferrite core sintered body.
上記のようにして得たフェライトコア焼結体に対して、一次側と二次側にそれぞれ５ターンの巻線を施したのち、交流Ｂ−Ｈループトレーサーを使用し、ＪＩＳ Ｃ ２５１４に準じて、周波数100ｋＨz、磁束密度0.2Ｔの条件で、−40〜140℃の温度範囲におけるコアロスＰcv(ｋＷ/ｍ3)を測定すると共に、Ｐcvの温度変化率α(ｋＷ/ｍ3/℃)を下記の計算式に基づいて求めた。
α＝{Ｐcv(Ｔmin−20)−Ｐcv(Ｔmin−60)}／40
なお、上記Ｔminは、コアロスの極小温度(℃)を表す。また、Ｐcv(Ｔmin−20)およびＰcv(Ｔmin−60)は、それぞれ(Ｔmin−20)(℃)および(Ｔmin−60)(℃)におけるコアロスを表す。通常、αは負の値であり、その絶対値が小さいことは、Ｔminに対して−20℃〜−60℃間の温度変化が小さいことを意味する。
The ferrite core sintered body obtained as described above is wound with 5 turns on each of the primary side and the secondary side, and then an AC B-H loop tracer is used according to JIS C 2514. The core loss Pcv (kW / m 3 ) in the temperature range of −40 to 140 ° C. is measured under the conditions of a frequency of 100 kHz and a magnetic flux density of 0.2 T, and the temperature change rate α (kW / m 3 / ° C.) of Pcv is as follows: It was calculated based on the following formula.
α = {Pcv (T min −20) −Pcv (T min −60)} / 40
Note that T min represents the minimum temperature (° C.) of the core loss. Pcv (T min −20) and Pcv (T min −60) represent core losses at (T min −20) (° C.) and (T min −60) (° C.), respectively. Usually, α is a negative value, and its small absolute value means that the temperature change between −20 ° C. and −60 ° C. is small with respect to T min .
また、上記各種の成分組成を有する造粒粉を用いて、成形圧118MPaで、直径13±0.5mm、長さ13±0.5mmの円柱体を各５個ずつ成形し、上記と同じ条件で焼成を行ってフェライト円柱焼結体とし、これを下記の欠け試験に供した。なお、得られた各種成分組成を有する円柱焼結体はいずれも、直径のばらつきは0.1mm未満、高さのばらつきは0.1mm未満、焼結密度のばらつきは0.05ｇ/cm3未満であった。 In addition, using the granulated powder having the above-mentioned various component compositions, 5 cylindrical bodies each having a diameter of 13 ± 0.5 mm and a length of 13 ± 0.5 mm are molded at a molding pressure of 118 MPa and fired under the same conditions as above. To obtain a ferrite cylindrical sintered body, which was subjected to the following chip test. The obtained cylindrical sintered bodies having various component compositions all had a diameter variation of less than 0.1 mm, a height variation of less than 0.1 mm, and a sintered density variation of less than 0.05 g / cm 3 . .
欠け試験は、日本粉末冶金工業会規格ＪＰＭＡ Ｐ ｌｌ「金属圧粉体のラトラ値測定方法」をフェライト焼結体に適用し、下記の要領で行った。上記円柱焼結体試料各５個を、内法径110mm×内法高さ120mmの鉄製円筒容器に投入し、この円筒容器を水平のローラー台上に載置し、150回／分で150分間回転させた。なお、上記回転条件においては、容器内に投入された試料は遠心力で容器内壁に張り付くこともなく、迫り上がりと自由落下運動を繰り返すことを確認した。この処理中に、試料同士および試料と鉄製容器内壁との衝突によって、円柱焼結体試料のエッジが欠損する。そこで、この処理の前と後のフェライト円柱試料の重量を0.001ｇ単位で測定し、その差から下記式で定義される欠損率Ｓ(％)を求めた。この欠損率Ｓは、小さいほど欠け強度が大きいことを意味する。
Ｓ＝{(Ａ−Ｂ)／Ａ}×100(％)
ただし、Ａ：試験前の５試料の総重量(ｇ)
Ｂ：試験後の５試料の破片を除く総重量(ｇ)
The chipping test was performed in the following manner by applying the Japan Powder Metallurgy Industry Association Standard JPMA Pll “Method for measuring the ratra value of metal green compact” to a ferrite sintered body. 5 each of the above cylindrical sintered body samples are put into an iron cylindrical container having an inner diameter of 110 mm and an inner height of 120 mm, and this cylindrical container is placed on a horizontal roller stand for 150 minutes at 150 times / minute. Rotated. Note that, under the above rotation conditions, it was confirmed that the sample put into the container did not stick to the inner wall of the container by centrifugal force, and repeated a rushing and free-falling motion. During this process, the edge of the cylindrical sintered body sample is lost due to the collision between the samples and the inner wall of the iron container. Therefore, the weight of the ferrite cylindrical sample before and after this treatment was measured in units of 0.001 g, and the defect rate S (%) defined by the following formula was obtained from the difference. The smaller the defect rate S, the greater the chip strength.
S = {(A−B) / A} × 100 (%)
However, A: Total weight (g) of 5 samples before the test
B: Total weight excluding debris of 5 samples after test (g)
上記測定の結果を、表１中に併記して示した。この表１から、フェライトの主成分の組成と微量成分の添加量を適切に制御した試料（Ｎｏ．１〜１４）においては、１００℃におけるコアロスは４００ｋＷ／ｍ３以下で、その温度変化率αの絶対値は４ｋＷ／ｍ３／℃以下であり、しかも、欠損率Ｓは２．０％以下で、いずれの特性も優れていることがわかる。一方、本発明を外れる成分組成の試料（Ｎｏ．１５〜２８）では、コアロスＰｃｖ、温度変化率αおよび欠損率Ｓのいずれか１つ以上の特性が劣っていた。 The results of the above measurements are shown together in Table 1. From Table 1, in the samples (Nos. 1 to 14) in which the composition of the main component of ferrite and the addition amount of trace components are appropriately controlled, the core loss at 100 ° C. is 400 kW / m 3 or less, and the temperature change rate α The absolute value of is 4 kW / m 3 / ° C. or less, and the defect rate S is 2.0% or less, indicating that both characteristics are excellent. On the other hand, in the sample (No. 15 to 28) having a component composition outside the present invention, any one or more of the core loss Pcv, the temperature change rate α, and the defect rate S was inferior.
フェライト焼結体の主成分組成が、Fe2Ｏ3：53.0mol％、ZnＯ：12.0mol％、CoＯ：0.20mol％およびMnＯ：34.8mol％で、微量成分の含有量が、SiＯ2：0.01mass％、CaＯ：0.07mass％、Nb2Ｏ5：0.020mass％およびTiＯ2：0.2mass％となるように原料を配合し、実施例１の手順にしたがって仮焼粉を作成し、粉砕し、ＰＶＡを0.6mass％となるよう添加し、造粒粉とした。この造粒粉について、温度を−10℃〜150℃、水分含有量を0.001〜20mass％に変化させると共に、成形に用いる金型の造粒粉が接する部位の温度を−10〜150℃に変化させて、実施例１と同様にして、リングコアと円柱体試料を成形して焼成し、コアロスＰcv、温度変化率αおよび欠損率Ｓを測定した。なお、Ｔminは90℃であった。 The main component composition of the ferrite sintered body is Fe 2 O 3 : 53.0 mol%, ZnO: 12.0 mol%, CoO: 0.20 mol% and MnO: 34.8 mol%, and the content of trace components is SiO 2 : 0.01 mass. %, CaO: 0.07mass%, Nb 2 O 5: 0.020mass% and TiO 2: blended material so that 0.2 mass%, to create the calcined powder according to the procedure of example 1, was pulverized, PVA Was added to 0.6 mass% to obtain granulated powder. About this granulated powder, while changing the temperature to -10 ° C to 150 ° C and the moisture content to 0.001 to 20 mass%, the temperature at the part where the granulated powder of the mold used for molding is in contact changes to -10 to 150 ° C. In the same manner as in Example 1, the ring core and the cylindrical sample were molded and fired, and the core loss Pcv, the temperature change rate α, and the defect rate S were measured. T min was 90 ° C.
上記測定の結果を表２に併記して示した。この表２から、造粒粉の温度を０〜１００℃、造粒粉の水分率を０．０１〜１０ｍａｓｓ％とし、かつ粉末成形用金型の造粒粉が接触する部位の金型温度を０〜１００℃に保持した条件下で成形された試料（Ｎｏ．３２〜３８、４１〜４３）は、１００℃におけるコアロスＰｃｖが４００ｋＷ／ｍ３以下で、温度変化率αの絶対値が４ｋＷ／ｍ３／℃以下で、かつ、欠損率Ｓは２．０％以下であり、いずれの特性も優れていることがわかる。一方、本発明を外れる試料（Ｎｏ．２９〜３１、３９，４０，４４〜５３）では、コアロスＰｃｖ、温度変化率αおよび欠損率Ｓのいずれか１つ以上の特性が劣っていた。 The results of the above measurements are shown together in Table 2. From Table 2, the temperature of the granulated powder is 0 to 100 ° C., the moisture content of the granulated powder is 0.01 to 10 mass%, and the mold temperature of the part where the granulated powder of the powder molding die contacts is Samples molded under conditions maintained at 0 to 100 ° C. (Nos. 32-38 and 41 to 43 ) have a core loss Pcv at 100 ° C. of 400 kW / m 3 or less and an absolute value of the temperature change rate α of 4 kW / m 3 / ° C. or lower, and the defect rate S is 2.0% or lower, indicating that all the characteristics are excellent. On the other hand, in samples (No. 29-31, 39, 40, 44-53) that depart from the present invention, any one or more of the core loss Pcv, temperature change rate α, and defect rate S was inferior.
Claims (2)
記
Ｓ＝｛（Ａ−Ｂ）／Ａ｝×１００（％）
ただし、Ａ：試験前の５試料の総重量（ｇ）
Ｂ：試験後の５試料の破片を除く総重量（ｇ） In the Mn—Zn based ferrite mainly composed of Fe 2 O 3 , MnO, ZnO and CoO, the composition of the main components is Fe 2 O 3 : 51 to 56 mol%, ZnO: 6 to 14 mol%, CoO: 0.05 ～0.4Mol%, the balance being MnO, further trace elements contained as internal numbers, SiO terms of oxide 2: 0.005~0.05mass%, CaO: 0.02~0.2mass %, Nb 2 O 5 : 0.005 to 0.05 mass%, TiO 2 : 0.01 to 0.5 mass%, and the component composition is defined by the following formula when a chip test is performed according to JPMA P11. A Mn—Zn-based ferrite characterized by having a defect rate S of 2.0% or less.
S = {(A−B) / A} × 100 (%)
However, A: Total weight (g) of 5 samples before the test
B: Total weight (g) excluding debris of 5 samples after the test
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| JP5089971B2 (en) * | 2006-12-11 | 2012-12-05 | Ｊｆｅフェライト株式会社 | MnCoZn ferrite and transformer core |
| JP5332254B2 (en) | 2008-03-25 | 2013-11-06 | Ｔｄｋ株式会社 | Ferrite sintered body |
| JP6330645B2 (en) * | 2014-12-16 | 2018-05-30 | Tdk株式会社 | Ferrite core, electronic component, and power supply |
| JP6416808B2 (en) * | 2016-02-15 | 2018-10-31 | Ｊｆｅケミカル株式会社 | MnZnCo ferrite |
| JP6454309B2 (en) * | 2016-08-25 | 2019-01-16 | Ｊｆｅケミカル株式会社 | MnZnCo ferrite |
| CN109311763A (en) * | 2017-04-12 | 2019-02-05 | 杰富意化学株式会社 | Rod-shaped MnZn FERRITE CORE and its manufacturing method and antenna |
| CN111943658B (en) * | 2020-06-30 | 2022-06-03 | 天通控股股份有限公司 | Wide-temperature-range low-loss MnZn ferrite material and preparation method thereof |
| US11958779B2 (en) | 2020-06-30 | 2024-04-16 | Tdg Holding Co., Ltd | MnZn ferrite material with wide temperature range and low consumption, and preparation method thereof |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5916307A (en) * | 1982-07-19 | 1984-01-27 | Nippon Ferrite Ltd | Ferrite core for rotary transformer and manufacture thereof |
| JPH0577216A (en) * | 1991-09-24 | 1993-03-30 | Murata Mfg Co Ltd | Method for molding powder by preheating |
| JP3288113B2 (en) * | 1993-03-31 | 2002-06-04 | ティーディーケイ株式会社 | Mn-Zn ferrite magnetic material |
| JPH08191011A (en) * | 1994-11-07 | 1996-07-23 | Kawasaki Steel Corp | Mn-zn-co based ferrite magnetic core material |
| JP3917325B2 (en) * | 1999-05-25 | 2007-05-23 | Ｊｆｅケミカル株式会社 | Ferrite |
| JP2001145909A (en) * | 1999-09-10 | 2001-05-29 | Seiko Instruments Inc | Method for holding ceramics |
| JP4135869B2 (en) * | 2002-03-27 | 2008-08-20 | Ｔｄｋ株式会社 | Ferrite sintered member and method for producing ferrite sintered member |
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2004
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20140139983A (en) * | 2013-05-28 | 2014-12-08 | 티디케이가부시기가이샤 | Ferrite and transformer |
| KR101990781B1 (en) * | 2013-05-28 | 2019-06-19 | 티디케이가부시기가이샤 | Ferrite and transformer |
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| Publication number | Publication date |
|---|---|
| JP2006044971A (en) | 2006-02-16 |
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