JP2014183056A - Magnetic material, process of manufacturing the same, and coating liquid used for manufacturing - Google Patents

Magnetic material, process of manufacturing the same, and coating liquid used for manufacturing Download PDF

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JP2014183056A
JP2014183056A JP2013054481A JP2013054481A JP2014183056A JP 2014183056 A JP2014183056 A JP 2014183056A JP 2013054481 A JP2013054481 A JP 2013054481A JP 2013054481 A JP2013054481 A JP 2013054481A JP 2014183056 A JP2014183056 A JP 2014183056A
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magnetic material
magnetic
coercive force
magnetization
silicon oxide
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JP6225440B2 (en
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Matahiro Komuro
又洋 小室
Yuichi Satsu
祐一 佐通
Tetsushi Maruyama
鋼志 丸山
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Showa Denko Materials Co Ltd
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Hitachi Chemical Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a magnetic material whose inflection point of a demagnetization curve is eliminated without reducing coercive force by using a material that contains no rare earth element.SOLUTION: The magnetic material includes: Fe- based particles 3 containing α-Fe or α-(Fe, Co); a ε phase 2 containing ε-FeOor ε-(Fe, Co)O; and aluminum-containing silicon oxide 1. The Fe- based particles 3 have an interface that is in contact with the ε phase 2, aluminum-containing silicon oxide 1, and such.

Description

本発明は、ε−Ｆｅ２Ｏ３含有結晶を非磁性酸化物で結着した磁性材料及びその製造方法及びその製造に用いるコーティング液に関する。 The present invention relates to a magnetic material obtained by binding an ε-Fe 2 O 3 -containing crystal with a nonmagnetic oxide, a method for producing the magnetic material, and a coating liquid used for the production.

磁性材料には、軟磁性材料と硬磁性材料とがあり、磁石材料は硬磁性材料に分類される。特に、焼結磁石は、その高磁気特性のため、種々の磁気回路に適用されている。中でも、ＮｄＦｅＢ系焼結磁石は、Ｎｄ２Ｆｅ１４Ｂ系結晶を主相とする高性能磁石であり、自動車、産業、発電機器、家電、医療、電子機器など広範囲の製品で使用され、その使用量が増加している。ＮｄＦｅＢ系焼結磁石には、希土類元素であるＮｄ以外に耐熱性確保のためにＤｙやＴｂなどの高価な重希土類元素が使用されている。この希土類元素は、希少であり、かつ、資源の偏在、資源保護等のため高騰しており、希土類元素使用量の削減に対する要求が高まっている。 Magnetic materials include soft magnetic materials and hard magnetic materials, and magnet materials are classified as hard magnetic materials. In particular, sintered magnets are applied to various magnetic circuits because of their high magnetic properties. Among them, NdFeB-based sintered magnets are high-performance magnets mainly composed of Nd 2 Fe 14 B-based crystals, and are used in a wide range of products such as automobiles, industry, power generation equipment, home appliances, medical equipment, and electronic equipment. The amount is increasing. In addition to Nd, which is a rare earth element, expensive heavy rare earth elements such as Dy and Tb are used for the NdFeB-based sintered magnet in order to ensure heat resistance. This rare earth element is scarce and has soared due to the uneven distribution of resources, protection of resources, and the like, and there is an increasing demand for reducing the amount of rare earth elements used.

上記のようなＮｄＦｅＢ系磁石に対し、希土類元素を使用せずに高保磁力が得られるε−Ｆｅ２Ｏ３が硬質磁性材として注目されている。 In contrast to the NdFeB magnets described above, ε-Fe 2 O 3 that can obtain a high coercive force without using rare earth elements has attracted attention as a hard magnetic material.

例えば、特許文献１には、ε−Ｆｅ２Ｏ３結晶のＦｅサイトの一部がＡｌで置換された構造、及び、シリカ（ＳｉＯ２）がコートされた構造が開示されている。 For example, Patent Document 1 discloses a structure in which a part of the Fe site of the ε-Fe 2 O 3 crystal is substituted with Al and a structure in which silica (SiO 2 ) is coated.

ε−Ｆｅ２Ｏ３の飽和磁化及び残留磁化は小さいため、磁化を必要とする材料として用いるためには、高磁化を有するＦｅ系磁性相との複合化が必要であり、Ｆｅを含む軟磁性相のコア部と、ε−Ｆｅ２Ｏ３で被覆した磁性材料の例が特許文献２に開示されている。 Since the saturation magnetization and residual magnetization of ε-Fe 2 O 3 are small, in order to use it as a material that requires magnetization, it must be combined with an Fe-based magnetic phase having high magnetization, and soft magnetism containing Fe An example of a magnetic material coated with a phase core and ε-Fe 2 O 3 is disclosed in Patent Document 2.

また、キュリー点を上昇させるためにＦｅ以外の元素をε−Ｆｅ２Ｏ３に添加した材料の組成が特許文献３に開示されている。 Further, Patent Document 3 discloses a composition of a material in which an element other than Fe is added to ε-Fe 2 O 3 in order to raise the Curie point.

特開２００８−０６０２９３号公報JP 2008-060293 A 特開２０１１−０３５００６号公報JP 2011-035006 A 国際公開第２００８／１４９７８５号International Publication No. 2008/149785

特許文献１においては、水酸化鉄沈殿の粒子表面にシランの加水分解によって生成したシリカがコーティングされ、その後の熱処理（９５０〜１１５０℃）によりシリカコーティング内の酸化反応が起こり、ε−Ｆｅ２Ｏ３が生成することが開示されている。 In Patent Document 1, silica produced by hydrolysis of silane is coated on the surface of iron hydroxide precipitated particles, and an oxidation reaction within the silica coating occurs by subsequent heat treatment (950 to 1150 ° C.), and ε-Fe 2 O 3 is produced.

ε−Ｆｅ２Ｏ３の減磁曲線（磁化曲線）は、特許文献１の図４に示されているように、保磁力が２０ｋＯｅとなるが、磁場（Ｈ）ゼロ付近の曲線には変曲点がみられ、エネルギー積が低下する。 The demagnetization curve (magnetization curve) of ε-Fe 2 O 3 has a coercive force of 20 kOe as shown in FIG. 4 of Patent Document 1, but the curve near the magnetic field (H) zero is inflection. A dot is seen and the energy product decreases.

また、特許文献１においては、ε−Ｆｅ２Ｏ３のＦｅのサイトを一部Ａｌで置換しているが、特許文献１の図３の結果から明らかなように、ＦｅサイトへのＡｌ置換は保磁力が低下する。 In Patent Document 1, the Fe site of ε-Fe 2 O 3 is partially substituted with Al. As is clear from the results of FIG. 3 of Patent Document 1, Al substitution to the Fe site is The coercive force decreases.

さらに、磁石性能の向上のためには、残留磁化を増加させることが必須である。   Furthermore, in order to improve the magnet performance, it is essential to increase the residual magnetization.

本発明の目的は、希土類元素を含まない材料を用いて、保磁力を低下させずに減磁曲線の変曲点を消失させた磁性材料を得ることにある。   An object of the present invention is to obtain a magnetic material in which the inflection point of the demagnetization curve is eliminated without reducing the coercive force, using a material that does not contain a rare earth element.

本発明の磁性材料は、α相を形成するＦｅ系材料と、ε相を形成するＦｅ系酸化物と、酸化ケイ素と、を含み、酸化ケイ素は、その結晶中にケイ素及び酸素以外の金属元素又は半金属元素を含み、α相は、ε相及び酸化ケイ素に接する界面を有することを特徴とする。   The magnetic material of the present invention includes an Fe-based material that forms an α phase, an Fe-based oxide that forms an ε phase, and silicon oxide, and the silicon oxide is a metal element other than silicon and oxygen in the crystal. Alternatively, it includes a metalloid element, and the α phase has an interface in contact with the ε phase and silicon oxide.

本発明によれば、希土類元素を使用しない高性能の磁石又は半硬質磁性材料が作製できる。これにより、資源セキュリティ向上及び低コスト化が図れ、応用製品の低コスト化が実現できる。   According to the present invention, a high-performance magnet or semi-hard magnetic material that does not use rare earth elements can be produced. Thereby, resource security improvement and cost reduction can be achieved, and cost reduction of applied products can be realized.

磁性材料の微細構造の例を示す模式図である。It is a schematic diagram which shows the example of the fine structure of a magnetic material. 磁性材料の微細構造の例を示す模式図である。It is a schematic diagram which shows the example of the fine structure of a magnetic material. 実施例１の磁性材料の製造工程を示すフローチャートである。3 is a flowchart showing a manufacturing process of a magnetic material of Example 1. 磁性材料の磁化と温度との関係を示すグラフである。It is a graph which shows the relationship between magnetization of a magnetic material, and temperature.

磁石としてフェライト磁石を超える性能を確保するためには、以下の条件が必要となる。   In order to ensure the performance exceeding the ferrite magnet as a magnet, the following conditions are required.

１）希土類元素を使用せず、磁化の値が大きいＦｅ系材料とε−Ｆｅ２Ｏ３を複合化させること。 1) A rare earth element is not used and a Fe-based material having a large magnetization value and ε-Fe 2 O 3 are combined.

２）ε−Ｆｅ２Ｏ３の減磁曲線において保磁力の１／２以下の磁界範囲で変曲点がある軟磁性成分を形成しないこと。 2) Do not form a soft magnetic component having an inflection point in a magnetic field range of ½ or less of the coercive force in the demagnetization curve of ε-Fe 2 O 3 .

３）ε−Ｆｅ２Ｏ３のキュリー点が２００℃以上であること。 3) The Curie point of ε-Fe 2 O 3 is 200 ° C. or higher.

本発明は、上記の課題を解決するものであり、主に次の手段を用いる。   The present invention solves the above problems, and mainly uses the following means.

１）Ｆｅ系材料とε−Ｆｅ２Ｏ３との磁気的な結合を生じさせ、ε−Ｆｅ２Ｏ３の安定性を高める。そのために、磁化が１００ｅｍｕ／ｇよりも大きいＦｅ系材料とε−Ｆｅ２Ｏ３の磁化を部分的に結合させる。 1) A magnetic coupling between the Fe-based material and ε-Fe 2 O 3 is generated to enhance the stability of ε-Fe 2 O 3 . For this purpose, the magnetization of ε-Fe 2 O 3 is partially coupled to the Fe-based material having a magnetization larger than 100 emu / g.

２）軟磁性を示すＦｅ系材料について、ε−Ｆｅ２Ｏ３及び酸化ケイ素と界面を有するものとする。特に、酸化ケイ素（ＳｉＯ２）におけるケイ素のサイトの一部を、ケイ素よりも酸化物形成自由エネルギーの小さい元素であるＡｌ、Ｔｉ、Ｍｇ、Ｃａ及びＺｒで置換する。このような元素置換により、酸化ケイ素には酸素濃度の不均一性が導入され、酸素欠乏あるいは酸素濃化部から成長するε−Ｆｅ２Ｏ３の構造安定性が増し、ε−Ｆｅ２Ｏ３の減磁曲線において保磁力の１／２以下の磁界範囲で変曲点がある軟磁性成分が減少する。 2) An Fe-based material exhibiting soft magnetism has an interface with ε-Fe 2 O 3 and silicon oxide. In particular, a part of silicon sites in silicon oxide (SiO 2 ) is substituted with Al, Ti, Mg, Ca, and Zr, which are elements having a lower oxide formation free energy than silicon. Such element substitution introduces non-uniformity of oxygen concentration into silicon oxide, increases the structural stability of ε-Fe 2 O 3 grown from oxygen deficient or oxygen-enriched portions, and ε-Fe 2 O 3 In the demagnetization curve, a soft magnetic component having an inflection point decreases in a magnetic field range of ½ or less of the coercive force.

本発明の具体的な手法は実施例に記載するが、磁気特性が向上した代表的なＦｅ／ＳｉＯ２系磁石の特徴を以下に示す。 Specific methods of the present invention will be described in Examples, but the characteristics of typical Fe / SiO 2 magnets with improved magnetic characteristics are shown below.

１）ＳｉＯ２のＳｉサイトの一部がＡｌ、Ｔｉ、Ｍｇ、Ｃａ及びＺｒのうち少なくとも一種の元素で置換されていること。 1) Part of the Si site of SiO 2 is substituted with at least one element of Al, Ti, Mg, Ca, and Zr.

２）上記ＳｉＯ２とε−Ｆｅ２Ｏ３とが界面を介して接触していること。 2) The SiO 2 and ε-Fe 2 O 3 are in contact via an interface.

３）ε−Ｆｅ２Ｏ３の磁化よりも大きな磁化をもったＦｅ系材料がε−Ｆｅ２Ｏ３と磁気的に結合していること。 3) ε-Fe 2 O Fe-based material ε-Fe 2 O 3 having a large magnetization than the magnetization of 3 and magnetically that bind to.

上記の特徴について更に詳しく説明する。   The above features will be described in more detail.

ＳｉＯ２のＳｉサイトの一部がＡｌなどの酸素と結合し易い元素で置換されると、ＳｉＯ２の中に酸素欠乏部が導入され、ε相（ε−Ｆｅ２Ｏ３）の核発生サイトとなり、Ｆｅ粒子の表面をε相で被覆することが可能となる。 When a part of the Si site of SiO 2 is replaced with an element that easily binds to oxygen, such as Al, an oxygen-deficient part is introduced into SiO 2 and the nucleation site of the ε phase (ε-Fe 2 O 3 ) Thus, it becomes possible to coat the surface of the Fe particles with the ε phase.

Ｓｉ以外の半金属元素や金属元素も、添加してＳｉの一部のサイトを置換可能であれば有効である。これらの元素のうち特に酸化鉄への拡散防止のために有効なものは、酸化物形成自由エネルギーが小さいＡｌ、Ｔｉ、Ｍｇ、Ｃａ及びＺｒである。   It is effective if metalloid elements and metal elements other than Si can be added to replace some sites of Si. Among these elements, those that are particularly effective for preventing diffusion into iron oxide are Al, Ti, Mg, Ca, and Zr, which have a low free energy for oxide formation.

これらの元素（Ｓｉ置換元素）の添加量は、０．１〜２０重量％が望ましい。添加量が０．１重量％未満の場合、その効果が表れない。一方、添加量が２０重量％を超えると、ε相以外の鉄酸化物が成長し、減磁曲線の制御が困難となる。また、添加量が２０重量％を超えると、一部の添加元素が酸化鉄にも含まれるようになり、保磁力や残留磁化が減少する。   The addition amount of these elements (Si-substituted elements) is preferably 0.1 to 20% by weight. When the addition amount is less than 0.1% by weight, the effect does not appear. On the other hand, when the addition amount exceeds 20% by weight, iron oxides other than the ε phase grow, and it becomes difficult to control the demagnetization curve. On the other hand, when the added amount exceeds 20% by weight, some of the added elements are included in the iron oxide, and the coercive force and the residual magnetization are reduced.

Ｆｅ系材料としては、ｂｃｃ構造のα−ＦｅやＦｅ−Ｃｏ合金の他、Ｆｅ−Ｎｉ、Ｆｅ−Ｃｒ、Ｆｅ−Ａｌ、Ｆｅ−Ｍｇ、Ｆｅ−Ｚｒ合金など、２０℃で５０〜２５０ｅｍｕ／ｇの飽和磁化を示す強磁性又はフェリ磁性を有する合金を使用することができる。５０ｅｍｕ／ｇ未満の飽和磁化では、磁化増加のために必要な体積が増加し、磁気的結合による保磁力制御が困難となる。   Fe-based materials include α-Fe and Fe—Co alloys having a bcc structure, Fe—Ni, Fe—Cr, Fe—Al, Fe—Mg, Fe—Zr alloys, etc., and 50 to 250 emu / g at 20 ° C. It is possible to use an alloy having a ferromagnetic or ferrimagnetic property that exhibits a saturation magnetization of. When the saturation magnetization is less than 50 emu / g, the volume necessary for increasing the magnetization increases, and it becomes difficult to control the coercive force by magnetic coupling.

以下、本発明の特徴をまとめて記載する。   Hereinafter, the features of the present invention will be described together.

本発明の磁性材料は、α−Ｆｅ又はα−（Ｆｅ，Ｃｏ）と、ε−Ｆｅ２Ｏ３又はε−（Ｆｅ，Ｃｏ）２Ｏ３と、酸化ケイ素と、を含み、酸化ケイ素は、その結晶中にケイ素及び酸素以外の金属元素又は半金属元素を含み、α−Ｆｅ又はα−（Ｆｅ，Ｃｏ）は、ε−Ｆｅ２Ｏ３又はε−（Ｆｅ，Ｃｏ）２Ｏ３、及び酸化ケイ素に接する界面を有することを特徴とする。 The magnetic material of the present invention includes α-Fe or α- (Fe, Co), ε-Fe 2 O 3 or ε- (Fe, Co) 2 O 3 and silicon oxide. The crystal contains a metal element or metalloid element other than silicon and oxygen, α-Fe or α- (Fe, Co) is ε-Fe 2 O 3 or ε- (Fe, Co) 2 O 3 , and It has an interface in contact with silicon oxide.

上記の金属元素又は半金属元素は、Ａｌ、Ｍｇ、Ｚｒ、Ｔｉ、Ｃａ及びＢａからなる群から選択されることが望ましい。   The metal element or metalloid element is preferably selected from the group consisting of Al, Mg, Zr, Ti, Ca, and Ba.

上記の金属元素又は半金属元素の濃度は、０．１〜２０重量％であることが望ましい。   The concentration of the metal element or metalloid element is preferably 0.1 to 20% by weight.

α−Ｆｅ又はα−（Ｆｅ，Ｃｏ）は、粒子状であり、形状異方性を有していることが望ましい。   α-Fe or α- (Fe, Co) is preferably in the form of particles and has shape anisotropy.

上記の界面のうちα−Ｆｅ又はα−（Ｆｅ，Ｃｏ）とε−Ｆｅ２Ｏ３又はε−（Ｆｅ，Ｃｏ）２Ｏ３とが接する部分の割合は、３０〜９８％であることが望ましい。 The ratio of the portion where α-Fe or α- (Fe, Co) and ε-Fe 2 O 3 or ε- (Fe, Co) 2 O 3 are in contact with each other is 30 to 98%. desirable.

本発明の磁性材料の製造方法は、ε−Ｆｅ２Ｏ３又はε−（Ｆｅ，Ｃｏ）２Ｏ３の原料である鉄を含む塩と、酸化ケイ素の原料である有機金属化合物と、金属元素又は半金属元素の原料と、を混合した溶液（コーティング液）を用い、α−Ｆｅ又はα−（Ｆｅ，Ｃｏ）の表面を上記の溶液で被覆し、加熱することを特徴とする。 The method for producing a magnetic material of the present invention includes a salt containing iron that is a raw material of ε-Fe 2 O 3 or ε- (Fe, Co) 2 O 3 , an organometallic compound that is a raw material of silicon oxide, and a metal element Alternatively, using a solution (coating solution) mixed with a raw material of a metalloid element, the surface of α-Fe or α- (Fe, Co) is coated with the above solution and heated.

本発明の磁性材料の製造方法は、ε−Ｆｅ２Ｏ３又はε−（Ｆｅ，Ｃｏ）２Ｏ３の原料である鉄を含む塩と、酸化ケイ素の原料である有機金属化合物と、を混合した溶液を用い、ゲル化し、加熱することによりε−Ｆｅ２Ｏ３又はε−（Ｆｅ，Ｃｏ）２Ｏ３を形成し、これを金属元素又は半金属元素の原料であるフッ化物溶液で被覆し、加熱することによりε−Ｆｅ２Ｏ３又はε−（Ｆｅ，Ｃｏ）２Ｏ３の一部を脱酸し、α−Ｆｅ又はα−（Ｆｅ，Ｃｏ）を形成してもよい。 In the method for producing a magnetic material of the present invention, a salt containing iron which is a raw material of ε-Fe 2 O 3 or ε- (Fe, Co) 2 O 3 and an organometallic compound which is a raw material of silicon oxide are mixed. The solution is gelled and heated to form ε-Fe 2 O 3 or ε- (Fe, Co) 2 O 3 and coated with a fluoride solution that is a raw material of a metal element or a metalloid element Then, by heating, a part of ε-Fe 2 O 3 or ε- (Fe, Co) 2 O 3 may be deoxidized to form α-Fe or α- (Fe, Co).

以下、実施例を用いて詳細に説明する。なお、本発明は、ここで取り上げた実施例に限定されることはなく、発明の技術的思想を逸脱しない範囲で適宜組み合わせや改良が可能である。   Hereinafter, it demonstrates in detail using an Example. It should be noted that the present invention is not limited to the embodiments taken up here, and can be appropriately combined and improved without departing from the technical idea of the invention.

図２は、本実施例の磁性材料の製造工程を示すフローチャートである。   FIG. 2 is a flowchart showing the manufacturing process of the magnetic material of this example.

硝酸鉄とテトラエチルオルトシランと水とを混合する（Ｓ１０１）。硝酸鉄の割合は、最終生成物であるＦｅ２Ｏ３が重量基準でＳｉＯ２に対して８０％となるようにする。テトラエチルオルトシランと水との混合比は１：１である。 Iron nitrate, tetraethylorthosilane, and water are mixed (S101). The proportion of iron nitrate is such that the final product Fe 2 O 3 is 80% based on weight with respect to SiO 2 . The mixing ratio of tetraethylorthosilane and water is 1: 1.

これに、エチルアルコールを均質な溶液になるように適当量加える（Ｓ１０２）。   An appropriate amount of ethyl alcohol is added to this so as to form a homogeneous solution (S102).

この溶液にアルミニウムエトキシドを１０％、粒径５０ｎｍのＦｅナノ粒子を１０ｗｔ％添加する（Ｓ１０３）。その後、ゲル化し、乾燥した後（Ｓ１０４）、１２００℃で３時間加熱し、その温度を保持する（Ｓ１０５）。その後、２℃／分の冷却速度で冷却する。   10% aluminum ethoxide and 10 wt% Fe nanoparticles with a particle size of 50 nm are added to this solution (S103). Then, after gelatinizing and drying (S104), it heats at 1200 degreeC for 3 hours, and hold | maintains the temperature (S105). Thereafter, it is cooled at a cooling rate of 2 ° C./min.

Ｓ１０５の加熱処理により、Ｆｅナノ粒子の表面にε−Ｆｅ２Ｏ３が成長する。Ｆｅナノ粒子の中心部は、ｂｃｃ（体心立方晶）構造のＦｅで構成され、Ｆｅナノ粒子の表面に形成されたε−Ｆｅ２Ｏ３は、斜方晶構造を有する。（Ｓｉ，Ａｌ）Ｏ２は、一部非晶質で複数の結晶構造を有する。 By the heat treatment in S105, ε-Fe 2 O 3 grows on the surface of the Fe nanoparticles. The central part of the Fe nanoparticle is composed of Fe having a bcc (body-centered cubic) structure, and ε-Fe 2 O 3 formed on the surface of the Fe nanoparticle has an orthorhombic structure. (Si, Al) O 2 is partially amorphous and has a plurality of crystal structures.

図１Ａは、作製した磁性材料の微細構造を模式的に示したものである。   FIG. 1A schematically shows the microstructure of the produced magnetic material.

本図において、Ｆｅ系粒子３（Ｆｅナノ粒子（α−Ｆｅ））の表面には、酸化鉄（ＩＩＩ）のε相２（ε−Ｆｅ２Ｏ３）が成長する。Ｆｅ系粒子３は、ε相２と接する界面を有している。これらの外側には、含アルミニウム酸化ケイ素１（（Ｓｉ，Ａｌ）Ｏ２）が形成されている。 In this figure, the ε phase 2 (ε-Fe 2 O 3 ) of iron (III) oxide grows on the surface of Fe-based particles 3 (Fe nanoparticles (α-Fe)). The Fe-based particle 3 has an interface in contact with the ε phase 2. Aluminum-containing silicon oxide 1 ((Si, Al) O 2 ) is formed outside these.

本図の場合、Ｆｅ系粒子３の大部分がε相２で覆われている。   In the case of this figure, most of the Fe-based particles 3 are covered with the ε phase 2.

アルミニウムエトキシドを添加することにより作製した上記の磁性材料は、α−Ｆｅ２Ｏ３の成長が抑制され、α−Ｆｅ（ｂｃｃ構造のＦｅ）とε−Ｆｅ２Ｏ３とが磁気的に結合する。そして、２０℃で測定した減磁曲線には、保磁力の１／２以下の磁界範囲で変曲点がみられない。これに対して、アルミニウムエトキシドを添加しない場合には、ε相（ε−Ｆｅ２Ｏ３）以外の酸化鉄が成長し、Ｆｅ及びε−Ｆｅ２Ｏ３以外のα−Ｆｅ／α−Ｆｅ２Ｏ３などの界面が形成され、α−Ｆｅの磁化反転が容易に起こるようになる。 In the above magnetic material prepared by adding aluminum ethoxide, the growth of α-Fe 2 O 3 is suppressed, and α-Fe (Fe of bcc structure) and ε-Fe 2 O 3 are magnetically coupled. To do. And in the demagnetization curve measured at 20 degreeC, an inflexion point is not seen in the magnetic field range below 1/2 of a coercive force. In contrast, when aluminum ethoxide is not added, iron oxide other than the ε phase (ε-Fe 2 O 3 ) grows, and α-Fe / α-Fe other than Fe and ε-Fe 2 O 3. An interface such as 2 O 3 is formed, and α-Fe magnetization reversal occurs easily.

図３は、アルミニウムエトキシドを添加した場合及び添加していない場合のフェリ磁性部（ε−Ｆｅ２Ｏ３）の磁化の温度依存性について測定した結果を示したものである。 FIG. 3 shows the measurement results of the temperature dependence of the magnetization of the ferrimagnetic part (ε-Fe 2 O 3 ) with and without the addition of aluminum ethoxide.

図中、曲線（１）がアルミニウムを添加していない場合であり、曲線（２）が１０％添加した場合である。   In the figure, curve (1) is a case where aluminum is not added, and curve (2) is a case where 10% is added.

本図から、以下のことがわかる。   From this figure, the following can be understood.

アルミニウムを添加しても、キュリー点は大きく変わらない。一方、添加したことにより、ε−Ｆｅ２Ｏ３以外の酸化鉄の成長が抑制されるため、キュリー点よりも３０℃高温側において、アルミニウムを添加した磁性材料の磁化は、キュリー点よりも３０℃低温側の磁化の１／１０以下となる。これに対して、アルミニウムを添加していない場合（１）、２５０℃においても磁化が認められる。 Even if aluminum is added, the Curie point does not change significantly. On the other hand, since the addition suppresses the growth of iron oxides other than ε-Fe 2 O 3 , the magnetization of the magnetic material to which aluminum is added is 30 ° higher than the Curie point on the 30 ° C. higher temperature side than the Curie point. 1/10 or less of the magnetization on the low temperature side. On the other hand, when aluminum is not added (1), magnetization is observed even at 250 ° C.

また、減磁曲線には、０．５ｋＯｅ未満の負磁界側において磁界変曲点として測定される。これは、軟磁性酸化物が形成されるためと考える。   The demagnetization curve is measured as a magnetic field inflection point on the negative magnetic field side of less than 0.5 kOe. This is considered because a soft magnetic oxide is formed.

上記条件で作製した（Ｓｉ，Ａｌ）Ｏ２がＦｅとε−Ｆｅ２Ｏ３との複合粒子を結着した材料は、残留磁化６０ｅｍｕ／ｇ、保磁力１７ｋＯｅ、ε−Ｆｅ２Ｏ３におけるキュリー点が２０５℃であり、レアメタルを使用しない磁石として各種家電・産業機器に適用できる。 The material in which (Si, Al) O 2 produced under the above conditions binds composite particles of Fe and ε-Fe 2 O 3 is a residual magnetization of 60 emu / g, a coercive force of 17 kOe, and a Curie in ε-Fe 2 O 3 . A point is 205 degreeC and it can apply to various household appliances and industrial equipment as a magnet which does not use a rare metal.

図１Ｂは、本実施例においてアルミニウムエトキシドを１０％から１％に変えた場合の組織を示したものである。   FIG. 1B shows the structure when the aluminum ethoxide is changed from 10% to 1% in this example.

本図において、含アルミニウム酸化ケイ素１の相の内部にもε相２が形成される。ε相２は、Ｆｅ系粒子３と含アルミニウム酸化ケイ素１との間にも成長する。ε相２によるＦｅ系粒子３の被覆率は５０〜９０％であるが、保磁力は１６ｋＯｅとなる。   In this figure, the ε phase 2 is also formed inside the aluminum-containing silicon oxide 1 phase. The ε phase 2 also grows between the Fe-based particles 3 and the aluminum-containing silicon oxide 1. The coverage of the Fe-based particles 3 by the ε phase 2 is 50 to 90%, but the coercive force is 16 kOe.

なお、本図に示すように、Ｆｅ系粒子３を覆うε相２の形状は、滑らかなドーム形状、滑らかな楕円形状、粗く凹凸を有する形状、先端部が尖った針状等の場合がある。   As shown in the figure, the shape of the ε phase 2 covering the Fe-based particles 3 may be a smooth dome shape, a smooth ellipse shape, a rough and uneven shape, a needle shape with a sharp tip, or the like. .

フェライト磁石を超える性能を有する材料とするためには、Ｆｅナノ粒子の粒径を５０〜１００ｎｍとし、粒子中心付近のＦｅの体積率を２０〜７０％の範囲で形成することが必要となる。   In order to obtain a material having performance exceeding that of the ferrite magnet, it is necessary that the Fe nanoparticle has a particle size of 50 to 100 nm and the volume ratio of Fe near the particle center is in the range of 20 to 70%.

実施例１と同様に、硝酸鉄とテトラエチルオルトシランと水とを混合する。硝酸鉄の割合は、最終生成物であるＦｅ２Ｏ３が重量基準でＳｉＯ２に対して８０％となるようにする。 As in Example 1, iron nitrate, tetraethylorthosilane, and water are mixed. The proportion of iron nitrate is such that the final product Fe 2 O 3 is 80% based on weight with respect to SiO 2 .

これに、硫酸カリウムアルミニウムを１０％、粒径５０ｎｍのＦｅ−１０ｗｔ％Ｃｏナノ粒子を２０ｗｔ％添加する。その後、１ｋＯｅの磁場中でゲル化し、水洗した後、乾燥する。その後、１２００℃で３時間加熱し、その温度を保持する。その後、２℃／分の冷却速度で冷却する。   To this, 10% potassium aluminum sulfate and 20 wt% Fe-10 wt% Co nanoparticles with a particle size of 50 nm are added. Thereafter, it is gelled in a magnetic field of 1 kOe, washed with water, and dried. Then, it heats at 1200 degreeC for 3 hours, and maintains the temperature. Thereafter, it is cooled at a cooling rate of 2 ° C./min.

加熱処理により、Ｆｅ−１０ｗｔ％Ｃｏナノ粒子の表面にε−Ｆｅ２Ｏ３が成長する。Ｆｅ−１０ｗｔ％Ｃｏ粒子の中心部は、ｂｃｃ（体心立方晶）構造のＦｅ−１０ｗｔ％Ｃｏで構成され、当該ナノ粒子の表面に形成されたε−Ｆｅ２Ｏ３は、斜方晶構造を有する。（Ｓｉ，Ａｌ）Ｏ２は、一部非晶質で複数の結晶構造を有する。 By the heat treatment, ε-Fe 2 O 3 grows on the surface of Fe-10 wt% Co nanoparticles. The central part of Fe-10 wt% Co particles is composed of b -10 (body centered cubic) Fe-10 wt% Co, and ε-Fe 2 O 3 formed on the surface of the nanoparticles has an orthorhombic structure. Have (Si, Al) O 2 is partially amorphous and has a plurality of crystal structures.

硫酸カリウムアルミニウムを添加することにより作製した上記の磁性材料は、α−Ｆｅ２Ｏ３の成長が抑制され、Ｃｏを含有するα−Ｆｅとε−Ｆｅ２Ｏ３とが磁気的に結合する。そして、２０℃で測定した減磁曲線には、保磁力の１／２以下の磁界範囲で変曲点がみられない。これに対して、硫酸カリウムアルミニウムを添加しない場合には、ε相（ε−Ｆｅ２Ｏ３）以外の酸化鉄が成長し、Ｆｅ及びε−Ｆｅ２Ｏ３以外のα−Ｆｅ／α−Ｆｅ２Ｏ３などの界面が形成され、α−Ｆｅの磁化反転が容易に起こるようになる。 In the above-mentioned magnetic material produced by adding potassium aluminum sulfate, the growth of α-Fe 2 O 3 is suppressed, and α-Fe containing Co and ε-Fe 2 O 3 are magnetically coupled. And in the demagnetization curve measured at 20 degreeC, an inflexion point is not seen in the magnetic field range below 1/2 of a coercive force. In contrast, when potassium aluminum sulfate is not added, iron oxide other than the ε phase (ε-Fe 2 O 3 ) grows, and α-Fe / α-Fe other than Fe and ε-Fe 2 O 3. An interface such as 2 O 3 is formed, and α-Fe magnetization reversal occurs easily.

上記条件で作製した（Ｓｉ，Ａｌ）Ｏ２がα−Ｆｅとε−Ｆｅ２Ｏ３との複合粒子を結着した材料は、残留磁化８０ｅｍｕ／ｇ、保磁力１８ｋＯｅ、ε−Ｆｅ２Ｏ３のキュリー点が２２５℃であり、レアメタルを使用しない磁石として各種家電・産業機器に適用できる。 The material in which (Si, Al) O 2 produced under the above conditions binds composite particles of α-Fe and ε-Fe 2 O 3 has a residual magnetization of 80 emu / g, a coercive force of 18 kOe, and ε-Fe 2 O 3. The Curie point is 225 ° C. and can be applied to various home appliances and industrial equipment as a magnet not using rare metals.

本実施例において、（Ｓｉ，Ａｌ）Ｏ２及びε−Ｆｅ２Ｏ３のα−Ｆｅを含有しない部分のキュリー温度は、上記のように２２５℃となるが、Ａｌを添加していない場合、キュリー点の３０℃高温側でも磁化が検出される。このキュリー点より高温側の磁化は、軟磁性酸化物が残留していることを示している。軟磁性酸化物は、α−Ｆｅ表面にも形成されるため、保磁力低下の要因となる。したがって、ε−Ｆｅ２Ｏ３以外の酸化鉄の成長を抑制させることが必要である。 In this example, the Curie temperature of (Si, Al) O 2 and ε-Fe 2 O 3 not containing α-Fe is 225 ° C. as described above, but when Al is not added, Magnetization is detected even at the 30 ° C. high temperature side of the Curie point. The magnetization on the higher temperature side than the Curie point indicates that the soft magnetic oxide remains. Since the soft magnetic oxide is also formed on the α-Fe surface, it causes a reduction in coercive force. Therefore, it is necessary to suppress the growth of iron oxides other than ε-Fe 2 O 3 .

Ａｌの添加により、ε−Ｆｅ２Ｏ３以外の酸化鉄の成長は抑制され、ε−Ｆｅ２Ｏ３以外の酸化鉄（α−Ｆｅ２Ｏ３など）の磁化を２０℃で１／１０未満にすることができる。ε−Ｆｅ２Ｏ３以外の酸化鉄（α−Ｆｅ２Ｏ３など）の磁化が２０℃で１／１０以上の場合には、減磁曲線に軟磁性成分が重なった変曲点が認められ、磁石特性である最大エネルギー積が低下する。 By adding Al, the growth of iron oxides other than ε-Fe 2 O 3 is suppressed, and the magnetization of iron oxides other than ε-Fe 2 O 3 (α-Fe 2 O 3 etc.) is less than 1/10 at 20 ° C. Can be. When the magnetization of iron oxide other than ε-Fe 2 O 3 (such as α-Fe 2 O 3 ) is 1/10 or more at 20 ° C., an inflection point where soft magnetic components overlap on the demagnetization curve is observed. As a result, the maximum energy product, which is a magnet characteristic, is reduced.

テトラエチルオルトシラン、水及びエチルアルコールを１：６：６のモル比で混合する。その後、硝酸鉄をＦｅ２Ｏ３の重量が３０重量％となるように混合する。 Tetraethylorthosilane, water and ethyl alcohol are mixed in a molar ratio of 1: 6: 6. Thereafter, iron nitrate is mixed so that the weight of Fe 2 O 3 is 30% by weight.

これに、アルミニウムエトキシドを１重量％、粒径１μｍのＦｅ粒子を１０ｗｔ％添加する。その後、ゲル化し、８０℃で乾燥した後、大気中、１３００℃で１０時間加熱し、その温度を保持する。その後、２℃／分の冷却速度で冷却する。   To this, 1 wt% of aluminum ethoxide and 10 wt% of Fe particles having a particle diameter of 1 μm are added. Then, after gelatinizing and drying at 80 degreeC, it heats at 1300 degreeC in air | atmosphere for 10 hours, and maintains the temperature. Thereafter, it is cooled at a cooling rate of 2 ° C./min.

得られた試料を６０ｋＯｅで着磁した後、磁気特性を評価した結果、残留磁束密度０．６Ｔ、保磁力１１ｋＯｅの等方性磁石が得られた。２０℃で測定した減磁曲線には、保磁力の１／２以下の磁界において変曲点が認められない。交流消磁などの消磁により、減磁曲線の低磁界（１ｋＯｅ以下）に変曲点を伴って軟磁性成分が認められるようになる。   The obtained sample was magnetized at 60 kOe, and the magnetic characteristics were evaluated. As a result, an isotropic magnet having a residual magnetic flux density of 0.6 T and a coercive force of 11 kOe was obtained. In the demagnetization curve measured at 20 ° C., no inflection point is observed in a magnetic field of ½ or less of the coercive force. Due to demagnetization such as AC demagnetization, a soft magnetic component is recognized with an inflection point in a low magnetic field (1 kOe or less) of a demagnetization curve.

本実施例のような残留磁束密度０．６Ｔ以上、保磁力１０ｋＯｅ以上の磁気特性を満足する磁石を得るためには、以下の条件が必要となる。   In order to obtain a magnet that satisfies the magnetic characteristics of a residual magnetic flux density of 0.6 T or more and a coercive force of 10 kOe or more as in this embodiment, the following conditions are required.

１）テトラエチルオルトシラン、水、エチルアルコール、硝酸鉄及びＳｉ以外の元素を含有する有機金属を添加した溶液を使用したゲル化プロセスを採用する。   1) A gelling process using a solution to which an organic metal containing an element other than tetraethylorthosilane, water, ethyl alcohol, iron nitrate and Si is added is employed.

２）ゲル化前に１００ｅｍｕ／ｇ以上の飽和磁化を有する強磁性粒子を混合・分散させる。   2) Mix and disperse ferromagnetic particles having a saturation magnetization of 100 emu / g or more before gelation.

３）強磁性粒子の表面に高保磁力の酸化鉄を成長させ、表面から強磁性粒子の内部にかけて成長させる。   3) Iron oxide having a high coercive force is grown on the surface of the ferromagnetic particle and grown from the surface to the inside of the ferromagnetic particle.

４）磁石を構成する主な相は、（Ｓｉ，Ａｌ）Ｏ２、ε−Ｆｅ２Ｏ３及びα−Ｆｅであり、添加されたＡｌは、他の鉄酸化物（α−Ｆｅ２Ｏ３、γ−Ｆｅ２Ｏ３など）の成長を抑制し、保磁力及び残留磁束密度の増加に寄与する。このような石英のＳｉ位置を置換するＡｌの添加効果は、添加量０．１重量％で認められるが、添加量が３０重量％より多い場合、Ａｌを含有する低保磁力鉄酸化物の成長を促し、磁気特性が低下する。 4) The main phases constituting the magnet are (Si, Al) O 2 , ε-Fe 2 O 3 and α-Fe, and the added Al is another iron oxide (α-Fe 2 O 3 , Γ-Fe 2 O 3, etc.), and contributes to an increase in coercive force and residual magnetic flux density. The effect of adding Al to replace the Si position of quartz is observed at an addition amount of 0.1% by weight, but when the addition amount is more than 30% by weight, the growth of low coercivity iron oxide containing Al is achieved. And the magnetic properties are reduced.

本実施例のようなＳｉＯ２中のＳｉサイトの一部を他の元素で置換して磁気特性の向上が認められた添加元素は、Ａｌ、Ｍｇ、Ｚｒ、Ｔｉ、Ｃａ及びＢａである。また、ＳｉＯ２／ε−Ｆｅ２Ｏ３界面近傍（界面中心から１０ｎｍ以内の領域）には、Ｆｅ、Ｓｉ及びＯ以外の元素が偏在し、ε−Ｆｅ２Ｏ３の磁化反転を抑制する効果がある。 Additive elements whose magnetic properties have been improved by substituting a part of the Si site in SiO 2 as in this embodiment are Al, Mg, Zr, Ti, Ca and Ba. Further, in the vicinity of the SiO 2 / ε-Fe 2 O 3 interface (region within 10 nm from the interface center), elements other than Fe, Si and O are unevenly distributed, and the effect of suppressing magnetization reversal of ε-Fe 2 O 3 There is.

ゲル化前の溶液中の硝酸鉄濃度が小さい場合、酸化鉄の核発生サイト数が減少し、混合したＦｅ粒子表面を酸化鉄で十分に被覆することが困難である。残留磁束密度０．６Ｔ以上とするためには、酸化鉄の表面被覆率を３０％以上とすることが望ましい。   When the concentration of iron nitrate in the solution before gelation is small, the number of iron oxide nucleation sites decreases, and it is difficult to sufficiently coat the mixed Fe particle surface with iron oxide. In order to obtain a residual magnetic flux density of 0.6 T or more, it is desirable that the surface coverage of iron oxide be 30% or more.

酸化鉄の核発生サイトをＦｅ粒子の表面近傍に集中させるためには、α−Ｆｅ粒子のキュリー点以下の温度で磁場印加することが有効である。これにより、Ｆｅ粒子の磁場配向と酸化鉄の被覆率向上が実現でき、被覆率は最高で９８％とすることが可能である。したがって、本工程では、α−Ｆｅ粒子表面のε−Ｆｅ２Ｏ３被覆率は、３０〜９８％であることが望ましい。 In order to concentrate the iron oxide nucleation sites near the surface of the Fe particles, it is effective to apply a magnetic field at a temperature below the Curie point of the α-Fe particles. Thereby, the magnetic field orientation of the Fe particles and the iron oxide coverage can be improved, and the coverage can be set to 98% at the maximum. Therefore, in this step, the ε-Fe 2 O 3 coverage on the surface of the α-Fe particles is desirably 30 to 98%.

扁平形状のＦｅ粉を金型に挿入し、１０ｋＯｅの磁場中で扁平粉の長軸方向を磁場方向に平行になるように成形する。圧縮応力は、５ｔ／ｃｍ２である。これにより、密度６ｇ／ｃｍ３の圧粉成形体が形成される。 A flat Fe powder is inserted into a mold and shaped so that the major axis direction of the flat powder is parallel to the magnetic field direction in a magnetic field of 10 kOe. The compressive stress is 5 t / cm 2 . Thereby, a compacting body with a density of 6 g / cm 3 is formed.

圧粉成形体には、扁平形状のＦｅ粉の長軸方向が磁場方向にほぼ平行になるように揃い、形状磁気異方性が認められる。この圧粉成形体には、連続気泡が形成されているため、液体を含浸することができる。含浸する液体は、テトラエチルオルトシラン、水及びエチルアルコールを１：６：６のモル比で混合した後、硝酸鉄をＦｅ２Ｏ３の重量が３０重量％となるように混合したものである。この液体を真空含浸した後、乾燥する。その後、大気中で１３００℃、１０時間加熱し、その温度を保持した後、２℃／分の冷却速度で冷却する。 In the green compact, the long axis direction of the flat Fe powder is aligned so as to be substantially parallel to the magnetic field direction, and shape magnetic anisotropy is recognized. The green compact is formed with open cells, so that it can be impregnated with liquid. The liquid to be impregnated is a mixture of tetraethylorthosilane, water and ethyl alcohol mixed at a molar ratio of 1: 6: 6, and then mixed with iron nitrate so that the weight of Fe 2 O 3 is 30% by weight. The liquid is vacuum impregnated and then dried. Then, it heats at 1300 degreeC for 10 hours in air | atmosphere, After cooling the temperature, it cools with the cooling rate of 2 degreeC / min.

これを６０ｋＯｅの磁界で圧粉成形体の作製の際に印加した磁場方向と同じ方向に着磁した結果、保磁力８ｋＯｅ、残留磁束密度０．９Ｔの磁石が得られた。磁石には、α−Ｆｅ、Ｆｅ２Ｏ３及びＳｉＯ２が認められ、ＳｉＯ２とα−Ｆｅとの間にＦｅ２Ｏ３が成長する。ＳｉＯ２は、磁石の表面から反対側の表面まで連続して形成され、Ｆｅ２Ｏ３も連続して成長する。Ｆｅ２Ｏ３とα−Ｆｅとは、交換結合及び静磁結合によって互いの磁化がその動きを抑制するため、減磁曲線は単調であり、５〜２０ｋＯｅの保磁力が発現する。 As a result of magnetizing this with the magnetic field of 60 kOe in the same direction as the magnetic field applied when the green compact was produced, a magnet with a coercive force of 8 kOe and a residual magnetic flux density of 0.9 T was obtained. Α-Fe, Fe 2 O 3 and SiO 2 are recognized in the magnet, and Fe 2 O 3 grows between SiO 2 and α-Fe. SiO 2 is formed continuously from the surface of the magnet to the opposite surface, and Fe 2 O 3 also grows continuously. Fe 2 O 3 and α-Fe have their demagnetization curves monotonous and exhibit a coercive force of 5 to 20 kOe because their mutual magnetization suppresses their movement by exchange coupling and magnetostatic coupling.

上記ＳｉＯ２にＡｌを１重量％添加し、Ｓｉと置換することにより、保磁力が０．５ｋＯｅ増加する。 By adding 1% by weight of Al to the SiO 2 and replacing it with Si, the coercive force is increased by 0.5 kOe.

このような０．２〜２ｋＯｅの保磁力増大は、Ａｌ以外にＰ、Ｋ、Ｃａ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｇａ、Ｇｅ、Ａｓ、Ｓｅ、Ｓｒ、Ｙ、Ｚｒ、Ｎｂ、Ｍｏ、Ａｇ、Ｉｎ、Ｓｎ、Ｓｂ、Ｃｓ、Ｂａ、Ｌａ、Ｃｅ、Ｈｆ、Ｔａ、Ｗ又はＢｉを０．２〜２％の範囲でＳｉＯ２に添加することにより実現できる。添加剤には、有機金属を使用した。これらの添加元素の中で、残留磁束密度を０．０５〜０．１Ｔ増加させ、かつ、保磁力を０．２〜２ｋＯｅ増加できる添加元素は、Ａｌ、Ｔｉ、Ｍｇ、Ｃａ及びＺｒである。 Such a coercive force increase of 0.2 to 2 kOe is not limited to Al but includes P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, and Sr. , Y, Zr, Nb, Mo, Ag, In, Sn, Sb, Cs, Ba, La, Ce, Hf, Ta, W or Bi added to SiO 2 in the range of 0.2-2% it can. An organic metal was used as the additive. Among these additive elements, additive elements that can increase the residual magnetic flux density by 0.05 to 0.1 T and increase the coercive force by 0.2 to 2 kOe are Al, Ti, Mg, Ca, and Zr.

粒径２０ｎｍのα−Ｆｅ粒子の表面に溶液による表面処理を使用してε−Ｆｅ２Ｏ３を成長させる。 Ε-Fe 2 O 3 is grown on the surface of α-Fe particles having a particle size of 20 nm using surface treatment with a solution.

溶液は、テトラエチルオルトシラン、水及びエチルアルコールを１：６：６のモル比で混合した後、硝酸鉄をＦｅ２Ｏ３の重量が２０重量％となるように混合し、アルミニウムエトキシドを１重量％添加したものである。 The solution was prepared by mixing tetraethylorthosilane, water, and ethyl alcohol in a molar ratio of 1: 6: 6, then mixing iron nitrate so that the weight of Fe 2 O 3 was 20 wt%, and adding aluminum ethoxide to 1 Added by weight%.

上記α−Ｆｅ粒子の表面に当該溶液を塗布した後、８０℃で乾燥し、Ａｒガス雰囲気で１２００℃、１時間加熱し、その温度を保持する。その後、１℃／分の冷却速度で冷却した。   After apply | coating the said solution to the surface of the said (alpha) -Fe particle | grain, it dries at 80 degreeC, heats at 1200 degreeC and 1 hour in Ar gas atmosphere, and maintains the temperature. Then, it cooled at the cooling rate of 1 degree-C / min.

α−Ｆｅ粒子の表面には、粒径約５ｎｍのε−Ｆｅ２Ｏ３が成長する。ε−Ｆｅ２Ｏ３は、磁場１０ｋＯｅ未満では残留磁化が磁場とともに増加し、交流磁場によって消磁可能である。したがって、分散性が要求される場合は、ε−Ｆｅ２Ｏ３の保磁力及び残留磁化を小さくし、磁気捕集の際には、磁場印加により残留磁化及び保磁力を発現させる。 On the surface of the α-Fe particles, ε-Fe 2 O 3 having a particle size of about 5 nm grows. In ε-Fe 2 O 3 , the remanent magnetization increases with the magnetic field when the magnetic field is less than 10 kOe, and can be demagnetized by the alternating magnetic field. Therefore, when dispersibility is required, the coercive force and the remanent magnetization of ε-Fe 2 O 3 are reduced, and the remanent magnetization and the coercive force are expressed by applying a magnetic field during magnetic collection.

１ｋＯｅの磁場印加により、α−Ｆｅ／ε−Ｆｅ２Ｏ３粒子の保磁力は、１０Ｏｅから２ｋＯｅに増加する。また、５ｋＯｅから交流減衰磁場を印加して保磁力を１０Ｏｅに戻すことが可能である。このような酸化鉄の保磁力制御により、粒子の分散性と磁気捕集性を両立することが可能であり、ライフサイエンス分野において、細胞、蛋白質、核酸またはその他の生体物質の定量分析、定性分析、分離および精製などの種々の用途に用いることができる。また、α−Ｆｅ／ε−Ｆｅ２Ｏ３粒子は、標的物質（目的とする生体物質）を検出するためのマーカーとして用いることもできる。 By applying a magnetic field of 1 kOe, the coercivity of the α-Fe / ε-Fe 2 O 3 particles increases from 10 Oe to 2 kOe. Moreover, it is possible to return the coercive force to 10 Oe by applying an AC attenuation magnetic field from 5 kOe. By controlling the coercive force of iron oxide, it is possible to achieve both particle dispersibility and magnetic scavenging. In the life science field, quantitative analysis and qualitative analysis of cells, proteins, nucleic acids or other biological substances It can be used for various applications such as separation and purification. The α-Fe / ε-Fe 2 O 3 particles can also be used as a marker for detecting a target substance (target biological substance).

硝酸鉄とテトラエチルオルトシランと水とを混合する。硝酸鉄の割合は、最終生成物であるＦｅ２Ｏ３が重量基準でＳｉＯ２に対して８０％となるようにする。これに、硫酸カリウムマグネシウムを１０％、粒径５０ｎｍのＦｅ−１０ｗｔ％Ｃｏナノ粒子を２０ｗｔ％添加する。その後、１ｋＯｅの磁場中でゲル化し、水洗した後、乾燥する。その後、１２００℃で３時間加熱し、その温度を保持する。その後、１℃／分の冷却速度で冷却する。 Mix iron nitrate, tetraethylorthosilane and water. The proportion of iron nitrate is such that the final product Fe 2 O 3 is 80% based on weight with respect to SiO 2 . To this, 10% potassium magnesium sulfate and 20 wt% Fe-10 wt% Co nanoparticles with a particle size of 50 nm are added. Thereafter, it is gelled in a magnetic field of 1 kOe, washed with water, and dried. Then, it heats at 1200 degreeC for 3 hours, and maintains the temperature. Then, it cools with the cooling rate of 1 degree-C / min.

加熱処理により、Ｆｅ−１０ｗｔ％Ｃｏナノ粒子の表面にε−Ｆｅ２Ｏ３が成長し、Ｆｅ−１０ｗｔ％Ｃｏ粒子の中心部は、ｂｃｃ（体心立方晶）構造のＦｅ−１０ｗｔ％Ｃｏで構成され、当該ナノ粒子の表面に形成されたε−Ｆｅ２Ｏ３は、斜方晶構造を有する。硫酸カリウムマグネシウム由来のマグネシウムを含む（Ｓｉ，Ｍｇ）Ｏ２は、一部非晶質で複数の結晶構造を有する。 By heat treatment, ε-Fe 2 O 3 grows on the surface of Fe-10 wt% Co nanoparticles, and the central part of Fe-10 wt% Co particles is Fe-10 wt% Co having a bcc (body-centered cubic) structure. Ε-Fe 2 O 3 that is configured and formed on the surface of the nanoparticle has an orthorhombic structure. (Si, Mg) O 2 containing magnesium derived from potassium magnesium sulfate is partially amorphous and has a plurality of crystal structures.

硫酸カリウムマグネシウムを添加することにより、α−Ｆｅ２Ｏ３の成長が抑制され、Ｃｏを含有するα−Ｆｅとε−Ｆｅ２Ｏ３とが磁気的に結合する。そして、２０℃で測定した減磁曲線には、保磁力の１／２以下の磁界範囲で変曲点がみられない。これに対して、硫酸カリウムマグネシウムを添加しない場合には、ε相（ε−Ｆｅ２Ｏ３）以外の酸化鉄が成長し、Ｆｅ及びε−Ｆｅ２Ｏ３以外のα−Ｆｅ／α−Ｆｅ２Ｏ３などの界面が形成され、α−Ｆｅの磁化反転が容易に起こるようになる。 By adding potassium magnesium sulfate, the growth of α-Fe 2 O 3 is suppressed, and α-Fe containing Co and ε-Fe 2 O 3 are magnetically coupled. And in the demagnetization curve measured at 20 degreeC, an inflexion point is not seen in the magnetic field range below 1/2 of a coercive force. In contrast, when potassium magnesium sulfate is not added, iron oxide other than the ε phase (ε-Fe 2 O 3 ) grows, and α-Fe / α-Fe other than Fe and ε-Fe 2 O 3. An interface such as 2 O 3 is formed, and α-Fe magnetization reversal occurs easily.

上記条件で作製した（Ｓｉ，Ｍｇ）Ｏ２がα−Ｆｅとε−Ｆｅ２Ｏ３との複合粒子を結着した材料は、残留磁化８０ｅｍｕ／ｇ、保磁力１８ｋＯｅ、ε−Ｆｅ２Ｏ３におけるキュリー点が２２５℃であり、レアメタルを使用しない磁石として各種家電・産業機器に適用できる。 The material in which (Si, Mg) O 2 produced under the above conditions binds composite particles of α-Fe and ε-Fe 2 O 3 has a residual magnetization of 80 emu / g, a coercive force of 18 kOe, and ε-Fe 2 O 3. The Curie point at 225 ° C. is applicable to various home appliances and industrial equipment as a magnet that does not use rare metals.

本実施例において、（Ｓｉ，Ｍｇ）Ｏ２及びε−Ｆｅ２Ｏ３のα−Ｆｅを含有しない粉末のキュリー温度は、上記のように２２５℃となる。一方、Ｍｇを添加していない材料の場合、キュリー点の３０℃高温側でも磁化が検出される。このキュリー点より高温側の磁化は、軟磁性酸化物が残留していることを示している。軟磁性酸化物は、α−Ｆｅの表面にも形成されるため、保磁力低下の要因となる。したがって、ε−Ｆｅ２Ｏ３以外の酸化鉄の成長を抑制させることが必要である。 In this example, the Curie temperature of the powder not containing α-Fe of (Si, Mg) O 2 and ε-Fe 2 O 3 is 225 ° C. as described above. On the other hand, in the case of a material to which no Mg is added, magnetization is detected even at the 30 ° C. high temperature side of the Curie point. The magnetization on the higher temperature side than the Curie point indicates that the soft magnetic oxide remains. Since the soft magnetic oxide is also formed on the surface of α-Fe, it causes a reduction in coercive force. Therefore, it is necessary to suppress the growth of iron oxides other than ε-Fe 2 O 3 .

Ｍｇの添加により、ε−Ｆｅ２Ｏ３以外の酸化鉄の成長は抑制され、ε−Ｆｅ２Ｏ３以外の酸化鉄（α−Ｆｅ２Ｏ３、γ−Ｆｅ３Ｏ４など）の磁化を２０℃で１／１０未満にすることができる。ε−Ｆｅ２Ｏ３以外の酸化鉄（α−Ｆｅ２Ｏ３、γ−Ｆｅ３Ｏ４など）の磁化が２０℃で１／１０以上の場合には、減磁曲線に軟磁性成分が重なった変曲点が認められ、磁石特性である最大エネルギー積が低下する。 By adding Mg, the growth of iron oxides other than ε-Fe 2 O 3 is suppressed, and the magnetization of iron oxides other than ε-Fe 2 O 3 (α-Fe 2 O 3 , γ-Fe 3 O 4, etc.) is reduced. It can be less than 1/10 at 20 ° C. When the magnetization of iron oxide other than ε-Fe 2 O 3 (α-Fe 2 O 3 , γ-Fe 3 O 4, etc.) is 1/10 or more at 20 ° C., the soft magnetic component overlaps the demagnetization curve. Inflection points are recognized, and the maximum energy product, which is a magnet characteristic, decreases.

本実施例においては、硫酸カリウムマグネシウムを添加しているが、硫酸カリウムマグネシウム以外に、チタン酸カリウム、硫酸カルシウム又は硫酸ジルコニウムを使用することができる。これにより、それぞれ、Ｔｉ、Ｃａ又はＺｒを含有する材料、すなわち、（Ｓｉ，Ｔｉ）Ｏ２、（Ｓｉ，Ｃａ）Ｏ２又は（Ｓｉ，Ｚｒ）Ｏ２を含有する材料を作製することができる。これにより、本実施例と同様に、ε−Ｆｅ２Ｏ３以外の酸化鉄の成長を抑制することができる。 In this embodiment, potassium magnesium sulfate is added, but potassium titanate, calcium sulfate or zirconium sulfate can be used in addition to potassium magnesium sulfate. Thereby, a material containing Ti, Ca or Zr, that is, a material containing (Si, Ti) O 2 , (Si, Ca) O 2 or (Si, Zr) O 2 , respectively, can be produced. . Thus, as in the present embodiment, it is possible to suppress the growth of iron oxide other than ε-Fe 2 O 3.

菱面体構造を有するε−Ｆｅ２Ｏ３をゾルゲル法により作製する。 Ε-Fe 2 O 3 having a rhombohedral structure is prepared by a sol-gel method.

オルトケイ酸テトラエチル（ＴＥＯＳ、Ｓｉ（ＯＣ２Ｈ５）４）とＨ２Ｏとエチルアルコールとを混合する。硝酸鉄の割合は、最終生成物であるＦｅ２Ｏ３が重量基準でＳｉＯ２に対して４０％となるようにする。これを２００℃に加熱した後、ゲル化する。これを大気中で１１００℃に加熱し、１時間保持する。その後、１０００℃まで１℃／ｍｉｎの冷却速度で徐冷した後、７００℃まで最大冷却速度１００℃／ｍｉｎで急冷する。 Tetraethyl orthosilicate (TEOS, Si (OC 2 H 5 ) 4 ), H 2 O and ethyl alcohol are mixed. The ratio of iron nitrate is such that the final product Fe 2 O 3 is 40% based on weight with respect to SiO 2 . This is heated to 200 ° C. and then gelled. This is heated to 1100 ° C. in the atmosphere and held for 1 hour. Then, after slow cooling to 1000 ° C. at a cooling rate of 1 ° C./min, rapid cooling to 700 ° C. at a maximum cooling rate of 100 ° C./min.

急冷して作製したε−Ｆｅ２Ｏ３の保磁力は、２７℃で２１〜２８ｋＯｅとなる。ε−Ｆｅ２Ｏ３の表面にＭｇＦ２を溶液処理により形成する。その後、加熱することにより、ε−Ｆｅ２Ｏ３の一部が脱酸され、α−Ｆｅが成長する。 The coercive force of ε-Fe 2 O 3 produced by quenching is 21 to 28 kOe at 27 ° C. MgF 2 is formed on the surface of ε-Fe 2 O 3 by solution treatment. Thereafter, by heating, a part of ε-Fe 2 O 3 is deoxidized and α-Fe grows.

ｂｃｃ構造を安定化させるためには、１００重量部のε−Ｆｅ２Ｏ３に対して０．１〜１０重量部のＣｏを添加しておくことにより、ε−（Ｆｅ，Ｃｏ）２Ｏ３からｂｃｃ−ＦｅＣｏ系粒子が成長し、構造安定化及び磁化増加を両立することができる。Ｃｏが０．１重量部未満の場合、構造安定化は可能であるが、磁化を増加することができない。Ｃｏが１０重量部を超えると、高価なＣｏを使用することによる原料費上昇のため、適用製品が限定される。５０重量部を超えると、ε−Ｆｅ２Ｏ３の保磁力が２０ｋＯｅ未満に低下する。 In order to stabilize the bcc structure, 0.1 to 10 parts by weight of Co is added to 100 parts by weight of ε-Fe 2 O 3 , so that ε- (Fe, Co) 2 O 3 is added. From this, bcc-FeCo-based particles grow and can achieve both structural stabilization and increased magnetization. When Co is less than 0.1 parts by weight, the structure can be stabilized, but the magnetization cannot be increased. If Co exceeds 10 parts by weight, the applied product is limited due to an increase in raw material costs due to the use of expensive Co. If it exceeds 50 parts by weight, the coercive force of ε-Fe 2 O 3 is reduced to less than 20 kOe.

脱酸されて成長したＦｅＣｏ系粒子は、飽和磁化が１５０〜２４０ｅｍｕ／ｇであり、ε−Ｆｅ２Ｏ３の値の７〜１５倍に達する。この高磁化ＦｅＣｏ系粒子がε−Ｆｅ２Ｏ３に対して１〜７０体積％の範囲で形成されることにより、残留磁束密度が２０〜１６０ｅｍｕ／ｇに増加する。 FeCo-based particles grown by deoxidation have a saturation magnetization of 150 to 240 emu / g, reaching 7 to 15 times the value of ε-Fe 2 O 3 . By forming the highly magnetized FeCo-based particles in the range of 1 to 70% by volume with respect to ε-Fe 2 O 3 , the residual magnetic flux density is increased to 20 to 160 emu / g.

α−Ｆｅの体積が１％未満の場合は、残留磁束密度の増加が２ｅｍｕ／ｇ未満で小さい。一方、α−Ｆｅの体積が７０％を超えると、保磁力が５ｋＯｅ以下に減少する。よって、上記１〜７０体積％であることが望ましい。   When the volume of α-Fe is less than 1%, the increase in residual magnetic flux density is small at less than 2 emu / g. On the other hand, when the volume of α-Fe exceeds 70%, the coercive force decreases to 5 kOe or less. Therefore, it is desirable that it is the said 1-70 volume%.

最外表面には酸フッ化物あるいはフッ化物が認められ、耐食性が向上する。すなわち、フッ化物の塗布及び脱酸熱処理を行うことにより、ε−（Ｆｅ，Ｃｏ）２Ｏ３／α−（Ｆｅ，Ｃｏ）を形成した上に、その外側にＭｇ（Ｏ，Ｆ）が成長するため、α−（Ｆｅ，Ｃｏ）の酸化を抑制する。さらに、フッ素の一部は、ε−Ｆｅ２Ｏ３と反応し、ε−Ｆｅ２（Ｏ，Ｆ）３を形成する。ε−Ｆｅ２（Ｏ，Ｆ）３／α−Ｆｅ、又はε−（Ｆｅ，Ｃｏ）２（Ｏ，Ｆ）３／α−（Ｆｅ，Ｃｏ）も認められ、残留磁束密度５０〜１７０ｅｍｕ／ｇ、保磁力（２７℃）１０〜２８ｋＯｅが実現できる。 On the outermost surface, oxyfluoride or fluoride is observed, and the corrosion resistance is improved. That is, ε- (Fe, Co) 2 O 3 / α- (Fe, Co) is formed by applying fluoride and performing deoxidation heat treatment, and Mg (O, F) grows on the outside thereof. Therefore, the oxidation of α- (Fe, Co) is suppressed. Further, some of fluorine will react with ε-Fe 2 O 3, to form the ε-Fe 2 (O, F ) 3. ε-Fe 2 (O, F) 3 / α-Fe or ε- (Fe, Co) 2 (O, F) 3 / α- (Fe, Co) is also observed, and the residual magnetic flux density is 50 to 170 emu / g. A coercive force (27 ° C.) of 10 to 28 kOe can be realized.

上記Ｃｏ含有酸化鉄にフッ化物を塗布した後、熱処理を施した磁粉のみを用いて、Ｚｎを焼結助材とし、加熱焼結することにより、焼結磁石を作製することができる。この焼結磁石（焼結体）は、密度が５．５〜６．５ｇ／ｃｍ３であり、最大エネルギー積（ＢＨｍａｘ）が５〜２０ＭＧＯｅの特性が得られる。 After applying a fluoride to the Co-containing iron oxide, a sintered magnet can be produced by using only the magnetic powder that has been heat-treated and using Zn as a sintering aid and heat-sintering. This sintered magnet (sintered body) has a density of 5.5 to 6.5 g / cm 3 and a maximum energy product (BHmax) of 5 to 20 MGOe.

本実施例で作製したＦｅ−Ｃｏ−Ｏ−Ｆ系磁石は、磁性相が強磁性及びフェリ磁性を示し、以下の特徴を有している。   The Fe—Co—O—F magnet produced in this example has a magnetic phase that is ferromagnetic and ferrimagnetic and has the following characteristics.

１）強磁性相のキュリー点がフェリ磁性相のネール点よりも高い。   1) The Curie point of the ferromagnetic phase is higher than the Neel point of the ferrimagnetic phase.

２）強磁性及びフェリ磁性相にはＣｏが含有している。また、磁気構造を保持したまま炭素や窒素ならびに硼素を１０原子％未満で含有してよい。これらの元素含有量が１０原子％を超えると、保磁力が急激に減少する。   2) Co is contained in the ferromagnetic and ferrimagnetic phases. Further, carbon, nitrogen and boron may be contained in less than 10 atomic% while maintaining the magnetic structure. When the content of these elements exceeds 10 atomic%, the coercive force decreases rapidly.

３）酸化物の一部にフッ素が入り込み、酸フッ化物が形成されている。   3) Fluoride enters part of the oxide to form an oxyfluoride.

４）フェリ磁性相は、菱面体晶である。   4) The ferrimagnetic phase is rhombohedral.

５）菱面体晶の｛００ｎ｝と強磁性相の容易磁化方向が磁気的に結合している。ここで、ｎは整数である。   5) The rhombohedral {00n} and the easy magnetization direction of the ferromagnetic phase are magnetically coupled. Here, n is an integer.

菱面体構造を有するε−Ｆｅ２Ｏ３をゾルゲル法により作製する。 Ε-Fe 2 O 3 having a rhombohedral structure is prepared by a sol-gel method.

オルトケイ酸テトラエチル（ＴＥＯＳ，Ｓｉ（ＯＣ２Ｈ５）４）とＨ２Ｏとエチルアルコールとを混合し、硝酸鉄を４０重量％加えて１５０℃に加熱した後、ゲル化する。ゲル化の際に５ｋＯｅの磁界を印加する。これを大気中で１１００℃に加熱し、１時間保持した後、１０００℃まで１℃／ｍｉｎの冷却速度で徐冷する。その後、７００℃まで最大冷却速度１００℃／ｍｉｎで急冷する。急冷して作製したε−Ｆｅ２Ｏ３の保磁力は、２７℃で２５〜３０ｋＯｅとなる。ε−Ｆｅ２Ｏ３の表面にＡｌＦ３を溶液処理により形成し、９００℃に加熱することにより、ε−Ｆｅ２Ｏ３の一部が脱酸され、α−Ｆｅ、Ａｌ２Ｏ３及びＡｌ２（Ｏ，Ｆ）３が成長する。 Tetraethyl orthosilicate (TEOS, Si (OC 2 H 5 ) 4 ), H 2 O and ethyl alcohol are mixed, and 40 wt% iron nitrate is added and heated to 150 ° C., followed by gelation. A magnetic field of 5 kOe is applied during gelation. This is heated to 1100 ° C. in the atmosphere, held for 1 hour, and then gradually cooled to 1000 ° C. at a cooling rate of 1 ° C./min. Thereafter, it is rapidly cooled to 700 ° C. at a maximum cooling rate of 100 ° C./min. The coercive force of ε-Fe 2 O 3 produced by quenching is 25 to 30 kOe at 27 ° C. By forming AlF 3 on the surface of ε-Fe 2 O 3 by solution treatment and heating to 900 ° C., a part of ε-Fe 2 O 3 is deoxidized, and α-Fe, Al 2 O 3 and Al 2 (O, F) 3 grows.

ゲル化の際に磁界を印加することにより、＜００ｎ＞が磁界方向に成長した板状粉を作製することができる。この板状粉を脱酸することにより、ε−Ｆｅ２Ｏ３／α−Ｆｅの界面が形成される。 By applying a magnetic field during gelation, it is possible to produce a plate-like powder in which <00n> has grown in the magnetic field direction. By deoxidizing this plate-like powder, an interface of ε-Fe 2 O 3 / α-Fe is formed.

板状粉のため、前記界面は特定面で最も面積を広くすることができ、磁場印加方向において保磁力が最大となる。特に、ε−Ｆｅ２Ｏ３の＜ｎ００＞／／α−Ｆｅ＜ｎ００＞の関係が磁場方向に平行である場合に保磁力が最大となる。ここで、ｎは正数である。 Due to the plate-like powder, the interface can have the largest area on a specific surface, and the coercive force is maximized in the magnetic field application direction. In particular, the coercive force is maximized when the <n00> // α-Fe <n00> relationship of ε-Fe 2 O 3 is parallel to the magnetic field direction. Here, n is a positive number.

ゲル化の際、又はゲル化の後の熱処理工程における磁界印加は、フェリ磁性相又はフェリ磁性相と強磁性相との混相粉に対して、核発生方位の優先成長を誘導し、又は磁気的な結合を有する方位関係を生みだすために有効であり、いずれも保磁力増加又は残留磁束密度の増加に繋がる。ゲル化の際の磁界強度は、印加する磁界が１ｋＯｅ以上であれば特定の結晶方位が成長し易くなり、形状磁気異方性や磁気異方性が増加する。１ｋＯｅ未満では特定結晶方位の優先成長は困難である。   Magnetic field application during gelation or in the heat treatment step after gelation induces preferential growth in the nucleation direction with respect to the ferrimagnetic phase or the mixed powder of the ferrimagnetic phase and the ferromagnetic phase, or magnetically. This is effective for producing an azimuth relationship having a strong coupling, which leads to an increase in coercive force or an increase in residual magnetic flux density. As for the magnetic field strength during gelation, if the applied magnetic field is 1 kOe or more, a specific crystal orientation is likely to grow, and the shape magnetic anisotropy and magnetic anisotropy increase. If it is less than 1 kOe, preferential growth in a specific crystal orientation is difficult.

本実施例においては、ＡｌＦ３膜を塗布形成し、加熱することにより、ε−Ｆｅ２Ｏ３／Ｆｅ／Ａｌ２（ＯＦ）３やε−（Ｆｅ，Ａｌ）２Ｏ３／Ｆｅ−Ａｌ／（Ａｌ，Ｆｅ）２（ＯＦ）３の界面構成が得られる。このような酸化鉄の脱酸により、飽和磁化の高い鉄基合金が酸化鉄と酸フッ化物との間に形成され、鉄基合金の酸化が抑制され、酸化鉄と鉄基合金との磁気的な結合により保磁力を維持し、残留磁化を増加させることが可能である。 In this example, an AlF 3 film is applied, formed, and heated, so that ε-Fe 2 O 3 / Fe / Al 2 (OF) 3 or ε- (Fe, Al) 2 O 3 / Fe—Al / An interface configuration of (Al, Fe) 2 (OF) 3 is obtained. By such deoxidation of iron oxide, an iron-base alloy with high saturation magnetization is formed between iron oxide and oxyfluoride, and the oxidation of the iron-base alloy is suppressed, and the magnetic interaction between iron oxide and iron-base alloy is reduced. It is possible to maintain the coercive force and to increase the remanent magnetization by proper coupling.

このような界面構成を有するため、鉄基合金が１０〜７０体積％で保磁力１０ｋＯｅ及び残留磁束磁化３０ｅｍｕ／ｇを超える磁気特性が得られる。特に、鉄基合金が５０〜７０体積％の場合は、残留磁化が１００〜１４０ｅｍｕ／ｇとなる。   Since it has such an interface configuration, the magnetic characteristics exceeding 10 coOg and coercive force of 10 kOe and residual magnetic flux magnetization of 30 emu / g can be obtained when the iron-based alloy is 10 to 70% by volume. In particular, when the iron-based alloy is 50 to 70% by volume, the residual magnetization is 100 to 140 emu / g.

上述のように、鉄基合金を５０〜７０体積％含有するε−（Ｆｅ，Ａｌ）２Ｏ３／Ｆｅ−Ａｌ／（Ａｌ，Ｆｅ）２（ＯＦ）３の界面構成を有する粉末を磁界中圧縮成形することにより、バインダーが有機材料である異方性ボンド磁石、又は低融点金属をバインダーとする焼結磁石を作製することができる。有機材料をバインダーとするボンド磁石の場合は、残留磁束密度が０．８〜１．２Ｔであり、保磁力が１０ｋＯｅであるものが得られる。 As described above, a powder having an interface configuration of ε- (Fe, Al) 2 O 3 / Fe—Al / (Al, Fe) 2 (OF) 3 containing 50 to 70% by volume of an iron-based alloy in a magnetic field. By compression molding, an anisotropic bonded magnet whose binder is an organic material or a sintered magnet having a low melting point metal as a binder can be produced. In the case of a bonded magnet using an organic material as a binder, a magnet having a residual magnetic flux density of 0.8 to 1.2 T and a coercive force of 10 kOe is obtained.

このようにして得られた磁石は、モータなどの回転機、ＭＲＩなどの医療機器、ハードディスクなど情報機器、発電機、自動車用各種電装品などに使用可能である。   The magnets thus obtained can be used for rotating machines such as motors, medical equipment such as MRI, information equipment such as hard disks, generators, and various electrical equipment for automobiles.

本実施例の酸化鉄には、ε−Ｆｅ２Ｏ３以外にα−Ｆｅ２Ｏ３、γ−Ｆｅ２Ｏ３又はβ−Ｆｅ２Ｏ３が１０ｗｔ％未満の量で混在していても良い。α−Ｆｅ２Ｏ３、γ−Ｆｅ２Ｏ３又はβ−Ｆｅ２Ｏ３が３０ｗｔ％を超えると、保磁力が著しく低下し、２０℃で５ｋＯｅとなる。また、α−Ｆｅ２Ｏ３、γ−Ｆｅ２Ｏ３又はβ−Ｆｅ２Ｏ３が２０ｗｔ％を超えると、減磁曲線の低磁界側に変曲点が認められる。また、菱面体晶、正方晶、斜方晶、六方晶などの立方晶よりも対称性が低い結晶構造を有する鉄含有酸化物、酸フッ化物又はフッ化物が、一部の粒子又は粉末に成長していても良い。特に、ε−（Ｆｅ，Ａｌ）２Ｏ３／ε−（Ｆｅ，Ａｌ）２（Ｏ，Ｆ）３／Ｆｅ−Ａｌ／（Ａｌ，Ｆｅ）２（ＯＦ）３のようにフェリ磁性相にフッ素が配置した場合、菱面体晶の結晶が歪み、結晶磁気異方性が増大するため、保磁力が増加する。フェリ磁性相中のフッ素濃度は、１原子％〜５０原子％の範囲である。当該フッ素濃度が１原子％未満の場合、結晶磁気異方性の増加は認められない。一方、当該フッ素濃度が５０原子％を超える場合、菱面体晶又は歪んだ菱面体晶とは別の結晶が安定となり、強磁性相とフェリ磁性相との磁気的結合を維持することが困難となる。 In the iron oxide of this example, α-Fe 2 O 3 , γ-Fe 2 O 3 or β-Fe 2 O 3 may be mixed in an amount of less than 10 wt% in addition to ε-Fe 2 O 3. . When α-Fe 2 O 3 , γ-Fe 2 O 3 or β-Fe 2 O 3 exceeds 30 wt%, the coercive force is remarkably lowered and becomes 5 kOe at 20 ° C. When α-Fe 2 O 3 , γ-Fe 2 O 3 or β-Fe 2 O 3 exceeds 20 wt%, an inflection point is recognized on the low magnetic field side of the demagnetization curve. In addition, iron-containing oxides, oxyfluorides, or fluorides having a crystal structure with lower symmetry than cubic crystals such as rhombohedral, tetragonal, orthorhombic, and hexagonal crystals grow into some particles or powders. You may do it. In particular, fluorine in the ferrimagnetic phase such as ε- (Fe, Al) 2 O 3 / ε- (Fe, Al) 2 (O, F) 3 / Fe—Al / (Al, Fe) 2 (OF) 3 When rhombohedral is arranged, the rhombohedral crystal is distorted and the magnetocrystalline anisotropy is increased, so that the coercive force is increased. The fluorine concentration in the ferrimagnetic phase is in the range of 1 atomic% to 50 atomic%. When the fluorine concentration is less than 1 atomic%, no increase in magnetocrystalline anisotropy is observed. On the other hand, when the fluorine concentration exceeds 50 atomic%, a crystal different from the rhombohedral crystal or the distorted rhombohedral crystal becomes stable, and it is difficult to maintain the magnetic coupling between the ferromagnetic phase and the ferrimagnetic phase. Become.

本実施例においては、ＡｌＦ３を使用したが、同様な効果は、他の室温で強磁性を示さない金属元素を含有するフッ化物または酸フッ化物を塗布することにより、酸化鉄／フッ素含有酸化鉄／鉄基合金／酸フッ化物のような界面構成又は層構成を得ることができ、これらの一部に前記金属元素が含有することにより、ＡｌＦ３と同等の高残留磁化及び高保磁力を実現可能である。 In this example, AlF 3 was used, but the same effect can be obtained by applying an iron oxide / fluorine-containing oxide by applying a fluoride or oxyfluoride containing a metal element that does not exhibit ferromagnetism at room temperature. Interfacial structure or layer structure such as iron / iron-based alloy / oxyfluoride can be obtained, and the high remanent magnetization and high coercive force equivalent to those of AlF 3 are realized by including the metal element in a part of them. Is possible.

１：含アルミニウム酸化ケイ素、２：ε相、３：Ｆｅ系粒子。   1: Aluminum-containing silicon oxide, 2: ε phase, 3: Fe-based particles.

Claims (9)

α−Ｆｅ又はα−（Ｆｅ，Ｃｏ）と、ε−Ｆｅ２Ｏ３又はε−（Ｆｅ，Ｃｏ）２Ｏ３と、酸化ケイ素と、を含み、前記酸化ケイ素は、その結晶中にケイ素及び酸素以外の金属元素又は半金属元素を含み、前記α−Ｆｅ又は前記α−（Ｆｅ，Ｃｏ）は、前記ε−Ｆｅ２Ｏ３又は前記ε−（Ｆｅ，Ｃｏ）２Ｏ３、及び前記酸化ケイ素に接する界面を有することを特徴とする磁性材料。 α-Fe or α- (Fe, Co), ε-Fe 2 O 3 or ε- (Fe, Co) 2 O 3 and silicon oxide, and the silicon oxide contains silicon and A metal element or metalloid element other than oxygen, wherein the α-Fe or α- (Fe, Co) is the ε-Fe 2 O 3 or the ε- (Fe, Co) 2 O 3 , and the oxidation A magnetic material having an interface in contact with silicon. 前記金属元素又は前記半金属元素は、Ａｌ、Ｍｇ、Ｚｒ、Ｔｉ、Ｃａ及びＢａからなる群から選択されることを特徴とする請求項１記載の磁性材料。   2. The magnetic material according to claim 1, wherein the metal element or the metalloid element is selected from the group consisting of Al, Mg, Zr, Ti, Ca, and Ba. 前記金属元素又は前記半金属元素の濃度は、０．１〜２０重量％であることを特徴とする請求項１記載の磁性材料。   The magnetic material according to claim 1, wherein a concentration of the metal element or the metalloid element is 0.1 to 20% by weight. 前記α−Ｆｅ又は前記α−（Ｆｅ，Ｃｏ）は、粒子状であり、形状異方性を有していることを特徴とする請求項１記載の磁性材料。   The magnetic material according to claim 1, wherein the α-Fe or the α- (Fe, Co) is in the form of particles and has shape anisotropy. 前記界面のうち前記α−Ｆｅ又は前記α−（Ｆｅ，Ｃｏ）と前記ε−Ｆｅ２Ｏ３又は前記ε−（Ｆｅ，Ｃｏ）２Ｏ３とが接する部分の割合は、３０〜９８％であることを特徴とする請求項１記載の磁性材料。 The ratio of the portion where the α-Fe or the α- (Fe, Co) and the ε-Fe 2 O 3 or the ε- (Fe, Co) 2 O 3 are in contact with each other is 30 to 98%. The magnetic material according to claim 1, wherein the magnetic material is a magnetic material. 請求項１記載の磁性材料の製造方法であって、前記ε−Ｆｅ２Ｏ３又は前記ε−（Ｆｅ，Ｃｏ）２Ｏ３の原料である鉄を含む塩と、前記酸化ケイ素の原料である有機金属化合物と、前記金属元素又は前記半金属元素の原料と、を混合した溶液を用い、前記α−Ｆｅ又は前記α−（Ｆｅ，Ｃｏ）の表面を前記溶液で被覆し、加熱することを特徴とする磁性材料の製造方法。 A manufacturing method of a magnetic material according to claim 1, wherein the ε-Fe 2 O 3 or the .epsilon. (Fe, Co) salt containing iron as a raw material of the 2 O 3, a raw material of the silicon oxide Using a solution in which an organometallic compound and a raw material of the metal element or the metalloid element are mixed, the surface of the α-Fe or the α- (Fe, Co) is coated with the solution and heated. A method for producing a magnetic material. 請求項１記載の磁性材料の製造方法であって、前記ε−Ｆｅ２Ｏ３又は前記ε−（Ｆｅ，Ｃｏ）２Ｏ３の原料である鉄を含む塩と、前記酸化ケイ素の原料である有機金属化合物と、を混合した溶液を用い、ゲル化し、加熱することにより前記ε−Ｆｅ２Ｏ３又は前記ε−（Ｆｅ，Ｃｏ）２Ｏ３を形成し、これを前記金属元素又は前記半金属元素の原料であるフッ化物溶液で被覆し、加熱することにより前記ε−Ｆｅ２Ｏ３又は前記ε−（Ｆｅ，Ｃｏ）２Ｏ３の一部を脱酸し、前記α−Ｆｅ又は前記α−（Ｆｅ，Ｃｏ）を形成することを特徴とする磁性材料の製造方法。 A manufacturing method of a magnetic material according to claim 1, wherein the ε-Fe 2 O 3 or the .epsilon. (Fe, Co) salt containing iron as a raw material of the 2 O 3, a raw material of the silicon oxide The solution is mixed with an organometallic compound, gelled, and heated to form the ε-Fe 2 O 3 or the ε- (Fe, Co) 2 O 3 , which is converted into the metal element or the half The ε-Fe 2 O 3 or a part of the ε- (Fe, Co) 2 O 3 is deoxidized by coating with a fluoride solution that is a raw material of the metal element and heating, and the α-Fe or the A method for producing a magnetic material, comprising forming α- (Fe, Co). α−Ｆｅ又はα−（Ｆｅ，Ｃｏ）と、ε−Ｆｅ２Ｏ３又はε−（Ｆｅ，Ｃｏ）２Ｏ３と、酸化ケイ素と、を含み、前記酸化ケイ素は、その結晶中にケイ素及び酸素以外の金属元素又は半金属元素を含み、前記α−Ｆｅ又は前記α−（Ｆｅ，Ｃｏ）は、前記ε−Ｆｅ２Ｏ３又は前記ε−（Ｆｅ，Ｃｏ）２Ｏ３、及び前記酸化ケイ素に接する界面を有する磁性材料を作製するための原料である液であって、前記ε−Ｆｅ２Ｏ３又は前記ε−（Ｆｅ，Ｃｏ）２Ｏ３の原料である鉄を含む塩と、前記酸化ケイ素の原料である有機金属化合物と、前記金属元素又は前記半金属元素の原料と、を混合したものであることを特徴とするコーティング液。 α-Fe or α- (Fe, Co), ε-Fe 2 O 3 or ε- (Fe, Co) 2 O 3 and silicon oxide, and the silicon oxide contains silicon and A metal element or metalloid element other than oxygen, wherein the α-Fe or α- (Fe, Co) is the ε-Fe 2 O 3 or the ε- (Fe, Co) 2 O 3 , and the oxidation A liquid which is a raw material for producing a magnetic material having an interface in contact with silicon, and a salt containing iron which is a raw material of the ε-Fe 2 O 3 or the ε- (Fe, Co) 2 O 3 ; A coating liquid comprising a mixture of an organometallic compound that is a raw material of the silicon oxide and a raw material of the metal element or the metalloid element. 前記金属元素又は前記半金属元素は、Ａｌ、Ｍｇ、Ｚｒ、Ｔｉ、Ｃａ及びＢａからなる群から選択されることを特徴とする請求項８記載のコーティング液。   9. The coating liquid according to claim 8, wherein the metal element or the metalloid element is selected from the group consisting of Al, Mg, Zr, Ti, Ca, and Ba.
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