JP2008078614A - Manufacturing method for isotropic iron-base rare-earth alloy magnet - Google Patents
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Abstract
Description
本発明は、各種モータやアクチュエータに好適に使用される永久磁石の製造方法に関し、特に鉄基希土類合金磁石の製造方法に関している。 The present invention relates to a method for manufacturing a permanent magnet suitably used for various motors and actuators, and particularly to a method for manufacturing an iron-based rare earth alloy magnet.
現在、Ｎｄ2Ｆｅ14Ｂ相などの硬磁性相（以下、「２−１４−１相」と称する場合がある。）と、鉄基硼化物やα−Ｆｅなどの軟磁性相とが磁気的に結合した組織構造を有するナノコンポジット型永久磁石が開発されている。 At present, a hard magnetic phase such as Nd 2 Fe 14 B phase (hereinafter sometimes referred to as “2-14-1 phase”) and a soft magnetic phase such as iron-based boride and α-Fe are magnetic. Nanocomposite permanent magnets have been developed that have a tissue structure bonded to.
「２−１４−１相」におけるＮｄは、他の希土類元素Ｒに置換されていても良く、また、Ｆｅの一部はＣｏおよび／またはＮｉによって置換されていても良い。更には、２−１４−１相のＢの一部はＣ（炭素）によって置換されていても良い。 Nd in the “2-14-1 phase” may be substituted with another rare earth element R, and a part of Fe may be substituted with Co and / or Ni. Furthermore, a part of B in the 2-14-1 phase may be substituted with C (carbon).
本出願人は、特定組成を有する合金にＴｉを添加することにより、その合金溶湯の冷却過程でα−Ｆｅ相の析出・成長を抑制し、２−１４−１相の結晶成長を優先的に進行させることを見出した。本出願人は、添加したＴｉの効果として微細な鉄基硼化物相やα−Ｆｅ相中に２−１４−１相が均一に分散した組織を有するナノコンポジット磁石の構成と製造方法を特許文献１や特許文献２に開示している。 By adding Ti to an alloy having a specific composition, the applicant suppresses the precipitation and growth of the α-Fe phase in the cooling process of the molten alloy, and gives priority to crystal growth of the 2-14-1 phase. I found it to progress. The applicant of the present invention describes a composition and manufacturing method of a nanocomposite magnet having a structure in which a 2-14-1 phase is uniformly dispersed in a fine iron-based boride phase or an α-Fe phase as an effect of added Ti. 1 and Patent Document 2.
従来、硬磁性相であるＮｄ2Ｆｅ14Ｂ型結晶相を主相として含有し、場合によっては主相の粒界に非磁性相が存在する単相系磁石が広く使用されている。特許文献３、４は単相系磁石を開示している。 Conventionally, single-phase magnets containing an Nd 2 Fe 14 B type crystal phase, which is a hard magnetic phase, as a main phase and a nonmagnetic phase at the grain boundary of the main phase are widely used. Patent Documents 3 and 4 disclose single-phase magnets.
これら、ナノコンポジット磁石や単相系磁石などの等方性Ｒ−Ｆｅ−Ｂ系急冷磁石は、いずれもナノメートルスケールの結晶粒径を有しており、合金の溶湯を超急冷法によって急速に冷却、凝固し、その後、多くの場合、熱処理を施すことにより結晶化させることによって作製される。
作製された磁石の磁気特性は、その結晶組織に左右される。従来、急冷磁石においては、結晶粒径が小さくなると結晶粒間の交換結合が強固になることにより磁気曲線の角形性が良好になり残留磁束密度Ｂrが向上する効果（レマネンスエンハンスメント）が得られるともに、保磁力が向上する可能性があることがわかっている。このため、磁石の結晶組織は、理想的な均一微細組織が実現することが望まれている。 The magnetic properties of the produced magnet depend on its crystal structure. Conventionally, quenching magnets have the effect of improving the residual magnetic flux density Br by improving the squareness of the magnetic curve by strengthening the exchange coupling between crystal grains when the crystal grain size becomes small (remanence enhancement). It is known that the coercivity may be improved. For this reason, it is desired that an ideal uniform microstructure be realized as the crystal structure of the magnet.
磁石の結晶組織は熱処理条件（昇温速度や保持温度）によって大きく変わる。例えば、緩やかに昇温させ、低温で保持して熱処理を施した場合は、２−１４−１相など、磁気特性に有利な結晶のみを成長させることができるものの、その結晶組織は不均一になる。また、急峻に昇温させ高温で保持して熱処理を施した場合は、α−Ｆｅ相などが異常粒成長してしまう。 The crystal structure of the magnet varies greatly depending on the heat treatment conditions (heating rate and holding temperature). For example, when the temperature is raised gently and heat treatment is performed at a low temperature, only crystals that are advantageous in magnetic properties, such as the 2-14-1 phase, can be grown, but the crystal structure is uneven. Become. In addition, when the temperature is increased rapidly and kept at a high temperature for heat treatment, α-Fe phase and the like grow abnormally.
従来の製造方法では、熱処理条件に選択肢の幅が少なく、良好な磁気特性を得られる熱処理条件は合金組成と１対１で決まってしまっていた。すなわち、合金組成が決まれば、その組成で最も良好な磁気特性を得られる熱処理条件が決まり、必然的に得られる合金組織も決まってしまうので、高い磁気特性のポテンシャル（飽和磁化Ｉs、固有保磁力ＨcJ）を持つ合金を見出しても組織が不均一のため、全体としては良好な特性が得られないことが多かった。すなわち、粒径のばらつきが大きいため、残留磁束密度Ｂr及び最大磁気エネルギー積（ＢＨ）maxが低く、また、減磁曲線の角形性も悪いことが多かった。 In the conventional manufacturing method, the range of options for the heat treatment conditions is small, and the heat treatment conditions for obtaining good magnetic properties are determined one-to-one with the alloy composition. In other words, once the alloy composition is determined, the heat treatment conditions for obtaining the best magnetic properties with that composition are determined, and the alloy structure that is inevitably obtained is also determined. Therefore, the potential of the high magnetic properties (saturation magnetization I s , intrinsic retention) is determined. Even when an alloy having a magnetic force H cJ ) is found, because the structure is not uniform, good characteristics as a whole cannot often be obtained. That is, since the variation in particle size is large, the residual magnetic flux density Br and the maximum magnetic energy product (BH) max are low, and the squareness of the demagnetization curve is often poor.
特に、軟磁性相として鉄基硼化物相およびα−Ｆｅ相の少なくとも一方を含有するナノコンポジット磁石においては、組織が不均一になるにつれて磁気特性が顕著に悪化する。 In particular, in a nanocomposite magnet containing at least one of an iron-based boride phase and an α-Fe phase as a soft magnetic phase, the magnetic properties are significantly deteriorated as the structure becomes non-uniform.
本発明は、上記課題を解決するためになされたものであり、その目的は、Ｎｄ−Ｆｅ−Ｂ系急冷磁石において結晶組織が均一に微細化された磁石を得ることにより、磁気特性の優れた磁石を提供することにある。 The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to obtain a magnet whose crystal structure is uniformly refined in an Nd—Fe—B type quenching magnet, thereby providing excellent magnetic properties. It is to provide a magnet.
本発明による等方性鉄基希土類合金磁石の製造方法は、組成式（Ｆｅ1-mＴm）100-x-y-z（Ｂ1-pＣp）xＲyＭzで表され、ＴはＣｏおよびＮｉからなる群から選択された１種類以上の元素、Ｒはイットリウムおよび希土類金属元素からなる群から選択された１種類以上の元素、ＭはＴｉ、Ｚｒ、Ａｌ、Ｓｉ、Ｖ、Ｍｎ、Ｃｕ、Ｚｎ、Ｇａ、Ｃｒ、Ｎｂ、Ｍｏ、Ａｇ、Ｈｆ、Ｔａ、Ｗ、Ｐｔ、Ａｕ、Ｐｂ、Ｂｉ、Ｓｎからなる群から選択された１種類以上の元素であり、４≦ｘ≦２０、４≦ｙ≦２０、０．１≦ｚ≦５、０≦ｍ≦０．８、０＜ｐ≦０．３の関係を満足する合金の溶湯を作製する工程と、前記合金の溶湯を急冷することにより、平均結晶粒径５０ｎｍ以下のＮｄ2Ｆｅ14Ｂ型化合物相が体積比率で全体の５％以上５０％以下存在する急冷合金を作製する冷却工程と、前記急冷合金に対して、磁界中でＮｄ2Ｆｅ14Ｂ型化合物相の結晶化温度以上の温度を保持する熱処理工程とを含む。 The method for producing an isotropic iron-based rare earth alloy magnet according to the present invention is represented by the composition formula (Fe 1-m T m ) 100-xyz (B 1-p C p ) x R y M z , where T is Co and One or more elements selected from the group consisting of Ni, R is one or more elements selected from the group consisting of yttrium and rare earth metal elements, M is Ti, Zr, Al, Si, V, Mn, Cu, One or more elements selected from the group consisting of Zn, Ga, Cr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au, Pb, Bi, Sn, 4 ≦ x ≦ 20, 4 ≦ a step of producing a molten alloy satisfying the relationship of y ≦ 20, 0.1 ≦ z ≦ 5, 0 ≦ m ≦ 0.8, 0 <p ≦ 0.3, and quenching the molten alloy The Nd 2 Fe 14 B type compound phase having an average crystal grain size of 50 nm or less is present in a volume ratio of 5% or more and 50% or less of the whole. And a heat treatment step for maintaining the quenching alloy at a temperature higher than the crystallization temperature of the Nd 2 Fe 14 B type compound phase in a magnetic field.
好ましい実施形態において、前記熱処理工程は２Ｔ以上の磁界中で行う。 In a preferred embodiment, the heat treatment step is performed in a magnetic field of 2T or more.
好ましい実施形態において、前記熱処理工程で前記急冷合金を保持する前記温度は４００℃以上８００℃以下である。 In a preferred embodiment, the temperature for holding the quenched alloy in the heat treatment step is 400 ° C. or higher and 800 ° C. or lower.
好ましい実施形態において、前記鉄基希土類合金磁石は、Ｎｄ2Ｆｅ14Ｂ型化合物相の平均結晶粒径が１０ｎｍ以上５０ｎｍ以下である。 In a preferred embodiment, in the iron-based rare earth alloy magnet, the average crystal grain size of the Nd 2 Fe 14 B type compound phase is 10 nm or more and 50 nm or less.
好ましい実施形態において、前記鉄基希土類合金磁石は、Ｎｄ2Ｆｅ14Ｂ型化合物相の結晶粒径の標準偏差が５ｎｍ以上２０ｎｍ以下である。 In a preferred embodiment, in the iron-based rare earth alloy magnet, the standard deviation of the crystal grain size of the Nd 2 Fe 14 B type compound phase is 5 nm or more and 20 nm or less.
好ましい実施形態において、１０≦ｘ≦１６、６≦ｙ≦１０の関係を満足し、ＭがＴｉを必須元素として含み、前記熱処理工程により、平均結晶粒径が５ｎｍ以上３０ｎｍ以下の鉄基硼化物相と前記Ｎｄ2Ｆｅ14Ｂ型化合物相とが混在するナノコンポジット組織を形成する。 In a preferred embodiment, an iron-based boride satisfying the relationship of 10 ≦ x ≦ 16, 6 ≦ y ≦ 10, M containing Ti as an essential element, and having an average crystal grain size of 5 nm to 30 nm by the heat treatment step A nanocomposite structure in which the phase and the Nd 2 Fe 14 B type compound phase are mixed is formed.
好ましい実施形態において、４≦ｘ≦８、６≦ｙ≦１０の関係を満足し、ＭがＴｉを必須元素として含み、前記熱処理工程により、平均結晶粒径が５ｎｍ以上３０ｎｍ以下のα−Ｆｅ相と前記Ｎｄ2Ｆｅ14Ｂ型化合物相とが混在するナノコンポジット組織を形成する。 In a preferred embodiment, an α-Fe phase satisfying the relationship of 4 ≦ x ≦ 8, 6 ≦ y ≦ 10, M contains Ti as an essential element, and has an average crystal grain size of 5 nm to 30 nm by the heat treatment step. And a nanocomposite structure in which the Nd 2 Fe 14 B type compound phase is mixed.
本発明では、熱処理前の急冷合金の組織を制御し、磁界中で熱処理を行うことにより、結晶粒が均一に微細化された等方性鉄基希土類合金磁石を作製できる。 In the present invention, an isotropic iron-based rare earth alloy magnet having crystal grains uniformly refined can be produced by controlling the structure of the quenched alloy before heat treatment and performing heat treatment in a magnetic field.
本発明が対象とする鉄基希土類合金磁石におけるＮｄ2Ｆｅ14Ｂ相の結晶化温度は、添加元素の種類によっても変動するが、概して４００〜６００℃程度の範囲にある。この温度は、Ｎｄ2Ｆｅ14Ｂ相のキュリー点Ｔc（Ｔc＝約２９０℃）よりも充分に高い温度である。このため、結晶化のための熱処理工程中に磁界を印加しても、急冷合金は印加磁界から磁気的に影響をほとんど受けないと考えられていた。 The crystallization temperature of the Nd 2 Fe 14 B phase in the iron-based rare earth alloy magnet targeted by the present invention varies depending on the type of additive element, but is generally in the range of about 400 to 600 ° C. This temperature is sufficiently higher than the Curie point T c (T c = about 290 ° C.) of the Nd 2 Fe 14 B phase. For this reason, even if a magnetic field is applied during the heat treatment step for crystallization, it is considered that the quenched alloy is hardly affected magnetically by the applied magnetic field.
本発明者は、熱処理前において平均結晶粒径５０ｎｍ以下のＮｄ2Ｆｅ14Ｂ型化合物相を体積比率で全体の５％以上５０％以下含む急冷合金に対して、結晶化のための熱処理を磁界中で行ってみたところ、磁界を印加しないで同様の熱処理を行った場合に比べ、均一で微細な結晶組織を形成できることを見出し、本発明を完成した。 The present inventor applied a heat treatment for crystallization to a quenched alloy containing 5% or more and 50% or less of the entire Nd 2 Fe 14 B type compound phase having an average crystal grain size of 50 nm or less before heat treatment. As a result, the inventors have found that a uniform and fine crystal structure can be formed as compared with the case where the same heat treatment is performed without applying a magnetic field, and the present invention has been completed.
なお、Ｎｄ2Ｆｅ14Ｂ相のキュリー点Ｔcは、ＣｏをＦｅに対して置換することによって上昇させることができることはよく知られているが、発明者らはＴc＞熱処理温度となる合金系についても本発明の効果が得られることを確認しており、磁界の印加によって結晶相が均一に微細化されるメカニズムは現時点で不明である。 Although it is well known that the Curie point T c of the Nd 2 Fe 14 B phase can be raised by substituting Co for Fe, the inventors have found that the alloy satisfies T c > heat treatment temperature. It has been confirmed that the effects of the present invention can also be obtained for the system, and the mechanism by which the crystal phase is uniformly refined by application of a magnetic field is unknown at this time.
また、後述するように、熱処理前の急冷合金の全体が非晶質である場合は、磁界を印加しても、本発明による均一微細化の効果は得られないことがわかった。すなわち、印加磁界は、結晶核の生成にはほとんど寄与せず、熱処理開始前に結晶核または前駆体が存在する場合において、初めて熱処理過程に影響を及ぼし得ることを確認した。 Further, as will be described later, it was found that the effect of uniform refinement according to the present invention cannot be obtained even when a magnetic field is applied when the entire quenched alloy before heat treatment is amorphous. That is, it was confirmed that the applied magnetic field hardly contributes to the generation of crystal nuclei, and can affect the heat treatment process for the first time when crystal nuclei or precursors exist before the start of heat treatment.
このように、本発明では、結晶化のための熱処理を行う前において既に所定範囲の体積比率でＮｄ2Ｆｅ14Ｂ型化合物相を含む急冷凝固合金に対して、磁界中で熱処理を行うことにより、結晶組織を均一に微細化できる。本発明で作製する磁石は異方性磁石ではなく、等方性磁石であるため、熱処理中の磁界印加は、磁気的な異方化のために行うものではなく、結晶組織の均一微細化のために行う点で従来技術から区別される。 Thus, in the present invention, by performing heat treatment in a magnetic field on a rapidly solidified alloy containing the Nd 2 Fe 14 B type compound phase in a predetermined volume ratio before performing the heat treatment for crystallization. The crystal structure can be uniformly refined. Since the magnet produced in the present invention is not an anisotropic magnet but an isotropic magnet, the magnetic field application during the heat treatment is not performed for magnetic anisotropy, and the crystal structure is uniformly refined. Therefore, it is distinguished from the prior art in terms of what it does.
本発明の製造方法は、磁石を構成する磁性相としてＮｄ2Ｆｅ14Ｂ型化合物相のみを含有する単相系磁石だけではなく、硬磁性相と軟磁性相とが磁気的に結合したナノコンポジット磁石を含むＮｄ−Ｆｅ−Ｂ系急冷磁石に広く適用できる。 The production method of the present invention is not limited to a single-phase magnet containing only a Nd 2 Fe 14 B type compound phase as a magnetic phase constituting a magnet, but a nanocomposite in which a hard magnetic phase and a soft magnetic phase are magnetically coupled. The present invention can be widely applied to Nd—Fe—B type quenching magnets including magnets.
〈熱処理前の急冷合金〉
組成式（Ｆｅ1-mＴm）100-x-y-z（Ｂ1-pＣp）xＲyＭzで表される合金溶湯を形成し、急冷することにより、急冷合金を作製する。ここで、ＴはＣｏおよびＮｉからなる群から選択された１種類以上の元素、Ｒはイットリウムおよび希土類金属元素からなる群から選択された１種類以上の元素、ＭはＴｉ、Ｚｒ、Ａｌ、Ｓｉ、Ｖ、Ｍｎ、Ｃｕ、Ｚｎ、Ｇａ、Ｃｒ、Ｎｂ、Ｍｏ、Ａｇ、Ｈｆ、Ｔａ、Ｗ、Ｐｔ、Ａｕ、Ｐｂ、Ｂｉ、Ｓｎからなる群から選択された１種類以上の元素であり、４≦ｘ≦２０、４≦ｙ≦２０、０．１≦ｚ≦５、０≦ｍ≦０．８、０＜ｐ≦０．３の関係を満足している。
<Quenched alloy before heat treatment>
A quenched alloy is produced by forming a molten alloy represented by the composition formula (Fe 1-m T m ) 100-xyz (B 1-p C p ) x R y M z and quenching. Here, T is one or more elements selected from the group consisting of Co and Ni, R is one or more elements selected from the group consisting of yttrium and rare earth metal elements, M is Ti, Zr, Al, Si And one or more elements selected from the group consisting of V, Mn, Cu, Zn, Ga, Cr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au, Pb, Bi, and Sn. ≦ x ≦ 20, 4 ≦ y ≦ 20, 0.1 ≦ z ≦ 5, 0 ≦ m ≦ 0.8, 0 <p ≦ 0.3.
急冷は、超急冷法によって行うことが好ましい。実用化されている主な超急冷法には、メルトスピニング法とストリップキャスト法とがある。 The rapid cooling is preferably performed by a super rapid cooling method. The main ultra-quenching methods in practical use include the melt spinning method and the strip cast method.
本発明においては、熱処理前の急冷合金の組織を、硬磁性相であるＲ2Ｆｅ14Ｂ相の平均結晶粒径が５０ｎｍ以下、その体積比率が５％以上５０％以下となるように作製する。このような急冷合金を作製するには、合金の冷却速度を１０3〜１０8Ｋ／ｓ（ケルビン／秒）、好適には１０4〜１０7Ｋ／ｓ、とすればよい。具体的な急冷条件は、合金の非晶質生成能によって多少異なるが、（Ｂ、Ｃ）の組成比率ｘが低下するほど、冷却速度を高め、組成比率ｘが増加するほど、冷却速度を低くすることが好ましい。 In the present invention, the structure of the quenched alloy before the heat treatment is prepared so that the average crystal grain size of the R 2 Fe 14 B phase, which is a hard magnetic phase, is 50 nm or less and the volume ratio is 5% or more and 50% or less. . In order to produce such a quenched alloy, the cooling rate of the alloy may be 10 3 to 10 8 K / s (Kelvin / second), preferably 10 4 to 10 7 K / s. The specific quenching conditions differ somewhat depending on the amorphous forming ability of the alloy, but the cooling rate increases as the composition ratio x of (B, C) decreases, and the cooling rate decreases as the composition ratio x increases. It is preferable to do.
なお、急冷合金中における結晶相の体積比率は、熱磁気天秤を用いて、室温から１０００℃までの各温度における急冷合金の見かけの重量を測定することにより求める。見かけ重量は合金に含まれる磁性相のキュリー点で大きく減少するため、その変化量を、キュリー点に対応する磁性相の飽和磁化で割った値を比較することにより算出する。なお、非磁性相が存在していないことはＸ線回折（Ｘ−Ｒａｙ Ｄｉｆｆｒａｃｔｉｏｎ）によって確認できる。熱処理後のＲ2Ｆｅ14Ｂ相の平均結晶粒径を５０ｎｍ以下にするためには、急冷合金中のＲ2Ｆｅ14Ｂ相の平均結晶粒径を５０ｎｍ以下にしておくことが必要である。 The volume ratio of the crystal phase in the quenched alloy is determined by measuring the apparent weight of the quenched alloy at each temperature from room temperature to 1000 ° C. using a thermomagnetic balance. Since the apparent weight greatly decreases at the Curie point of the magnetic phase contained in the alloy, the amount of change is calculated by comparing the value divided by the saturation magnetization of the magnetic phase corresponding to the Curie point. The absence of the nonmagnetic phase can be confirmed by X-ray diffraction. In order to make the average crystal grain size of the R 2 Fe 14 B phase after heat treatment 50 nm or less, it is necessary to keep the average crystal grain size of the R 2 Fe 14 B phase in the quenched alloy to 50 nm or less.
急冷合金中のＲ2Ｆｅ14Ｂ相の平均結晶粒径は３０ｎｍ以下が好ましく、２０ｎｍ以下がより好ましい。また、急冷合金中のＲ2Ｆｅ14Ｂ相の体積比率が５％未満では、結晶核となるＲ2Ｆｅ14Ｂ相の結晶粒の絶対数が少ないため、熱処理後の金属組織は当然粗大になってしまう。 The average crystal grain size of the R 2 Fe 14 B phase in the quenched alloy is preferably 30 nm or less, and more preferably 20 nm or less. Further, when the volume ratio of the R 2 Fe 14 B phase in the quenched alloy is less than 5%, the absolute number of crystal grains of the R 2 Fe 14 B phase serving as a crystal nucleus is small, so that the metal structure after heat treatment is naturally coarse. turn into.
急冷合金中のＲ2Ｆｅ14Ｂ相の平均結晶粒径が５０％を超えると、初期の急冷組織のＲ2Ｆｅ14Ｂ相の結晶粒経の標準偏差が５０ｎｍを超えてしまい、各粒の曲率の違いが駆動力となり、大きい粒がより優先的に成長する。この場合、磁界の有無に依らず、熱処理後の金属組織は粗大になってしまう。そのため、磁界エネルギーを与える効果がより顕著で、結晶の粗大化を防ぎ、均一微細な結晶組織とするためには急冷合金中のＲ2Ｆｅ14Ｂ相の体積比率は１０％以上、３０％以下であることがより好ましい。 When the average grain size of the R 2 Fe 14 B phase in the quenched alloy exceeds 50%, the standard deviation of the crystal grain size of the R 2 Fe 14 B phase in the initial quenched structure exceeds 50 nm. The difference in curvature becomes the driving force, and large grains grow more preferentially. In this case, the metal structure after the heat treatment becomes coarse regardless of the presence or absence of a magnetic field. Therefore, the effect of giving magnetic field energy is more remarkable, the volume ratio of the R 2 Fe 14 B phase in the quenched alloy is 10% or more and 30% or less in order to prevent coarsening of the crystal and to obtain a uniform fine crystal structure. It is more preferable that
軟磁性相として鉄基硼化物相を含有するナノコンポジット磁石を作製する場合、上述した組成式を更に限定し、１０≦ｘ≦１６、６≦ｙ≦１０の関係を満足し、ＭがＴｉを必須元素として含むように調整する。Ｔｉは、急冷凝固過程においてＲ2Ｆｅ14Ｂ相以外の結晶相が析出・粗大化することを抑制する効果を発揮する。その結果、後述する熱処理工程により、平均結晶粒径が５ｎｍ以上３０ｎｍ以下の鉄基硼化物相と平均結晶粒径が５０ｎｍ以下のＮｄ2Ｆｅ14Ｂ型化合物相とが混在するナノコンポジット組織を形成することができる。 When producing a nanocomposite magnet containing an iron-based boride phase as a soft magnetic phase, the above-described composition formula is further limited, and 10 ≦ x ≦ 16 and 6 ≦ y ≦ 10 are satisfied, and M is Ti. Adjust to include as an essential element. Ti exhibits the effect of suppressing the precipitation and coarsening of crystal phases other than the R 2 Fe 14 B phase during the rapid solidification process. As a result, a nanocomposite structure in which an iron-based boride phase having an average crystal grain size of 5 nm to 30 nm and an Nd 2 Fe 14 B-type compound phase having an average crystal grain size of 50 nm or less is mixed is formed by a heat treatment process described later. can do.
一方、軟磁性相としてα−Ｆｅ相を含有するナノコンポジット磁石を作製する場合、前述の組成式を限定し、４≦ｘ≦８、６≦ｙ≦１０の関係を満足し、ＭがＴｉを必須元素として含むように調整する。この場合、熱処理工程により、平均結晶粒径が５ｎｍ以上３０ｎｍ以下のα−Ｆｅ相と平均結晶粒径が５０ｎｍ以下のＮｄ2Ｆｅ14Ｂ型化合物相とが混在するナノコンポジット組織を形成することができる。 On the other hand, when producing a nanocomposite magnet containing an α-Fe phase as a soft magnetic phase, the above composition formula is limited, and the relations 4 ≦ x ≦ 8 and 6 ≦ y ≦ 10 are satisfied, and M is Ti. Adjust to include as an essential element. In this case, a nanocomposite structure in which an α-Fe phase having an average crystal grain size of 5 nm or more and 30 nm or less and an Nd 2 Fe 14 B type compound phase having an average crystal grain size of 50 nm or less is mixed can be formed by the heat treatment step. it can.
本発明の熱処理においては、硬磁性相にくらべてキュリー点が相対的に高い軟磁性相が硬磁性相に比べて磁界の影響を受けやすい。このため最終的な磁石を構成する磁性相として、軟磁性相を含むナノコンポジット磁石では、従来困難であった軟磁性相が均一微細に分散した金属組織となり、Ｎｄ2Ｆｅ14Ｂ型化合物相のみを含有する単相系磁石よりも本発明の効果を奏しやすく、磁気特性の向上効果がより顕著に現れると考えられる。 In the heat treatment of the present invention, the soft magnetic phase having a relatively high Curie point compared to the hard magnetic phase is more susceptible to the influence of the magnetic field than the hard magnetic phase. Therefore, in the nanocomposite magnet including the soft magnetic phase as the magnetic phase constituting the final magnet, the soft magnetic phase, which has been difficult in the past, becomes a metal structure uniformly dispersed finely, and only the Nd 2 Fe 14 B type compound phase is obtained. It is considered that the effect of the present invention is more easily achieved than the single-phase magnet containing, and the effect of improving the magnetic properties appears more remarkably.
なお、軟磁性相としてα−Ｆｅ相を含有するナノコンポジット磁石を本発明の製造方法によって作製した場合、従来の熱処理工程を経たナノコンポジット磁石に比べ、残留磁束密度Ｂr、固有保磁力ＨcJ、最大磁気エネルギー積（ＢＨ）maxが向上する効果に加え、飽和磁化Ｉsが向上する効果も得られた。この効果は、硬磁性相に比べてキュリー点の高い軟磁性相が磁界の影響をより受けやすいことに起因していると考えられる。本発明では、α−Ｆｅ相の体積率が向上することにより、飽和磁化Ｉsが向上したと推定される。しかしながら、均一微細化の効果と同様、その詳細なメカニズムは現時点で不明である。 When a nanocomposite magnet containing an α-Fe phase as a soft magnetic phase is produced by the production method of the present invention, the residual magnetic flux density B r and the intrinsic coercive force H cJ are compared with a nanocomposite magnet that has undergone a conventional heat treatment process. in addition to the maximum magnetic energy product (BH) max are improved effects, effects also obtained of improving the saturation magnetization I s. This effect is considered to be caused by the fact that the soft magnetic phase having a higher Curie point is more easily affected by the magnetic field than the hard magnetic phase. In the present invention, by volume fraction of alpha-Fe phase is increased, it is estimated that the saturation magnetization I s is improved. However, the detailed mechanism is unclear at present, as is the effect of uniform miniaturization.
〈磁界中熱処理〉
上記のようにして作製した急冷合金を磁界中で熱処理を行う。磁界の強度は、０．５Ｔ以上１４Ｔ以下にすることが好ましく、２Ｔ以上１０Ｔ以下にすることが更に好ましい。磁界強度が０．５Ｔ未満の印加では、磁界のエネルギーが小さすぎるため、本発明による効果が不充分である。一方、１４Ｔを超える磁界を発生させるためには必要な設備と電力が莫大になるため不都合である。
<Heat treatment in magnetic field>
The quenched alloy produced as described above is heat-treated in a magnetic field. The strength of the magnetic field is preferably 0.5T or more and 14T or less, and more preferably 2T or more and 10T or less. When the magnetic field strength is less than 0.5T, the magnetic field energy is too small, and the effect of the present invention is insufficient. On the other hand, in order to generate a magnetic field exceeding 14T, it is inconvenient because necessary facilities and electric power become enormous.
熱処理温度は４００℃〜８００℃が好ましく、５５０℃〜７８０℃がより好ましい。４００℃未満では、Ｒ2Ｆｅ14Ｂ相の成長が生じにくく、８００℃を超えると、α−Ｆｅの結晶化および粗大化がおこりやすくなってしまう。昇温速度は０．１〜５０Ｋ／ｓが好ましく、１〜１０Ｋ／ｓがより好ましい。その理由は０．１Ｋ／ｓ未満では処理時間がかかり過ぎ、５０Ｋ／ｓを超えると異常粒成長がおこる可能性があるためである。 The heat treatment temperature is preferably 400 ° C to 800 ° C, more preferably 550 ° C to 780 ° C. If it is less than 400 ° C., the growth of the R 2 Fe 14 B phase is difficult to occur, and if it exceeds 800 ° C., crystallization and coarsening of α-Fe are likely to occur. The temperature rising rate is preferably 0.1 to 50 K / s, and more preferably 1 to 10 K / s. The reason is that if it is less than 0.1 K / s, it takes too much processing time, and if it exceeds 50 K / s, abnormal grain growth may occur.
磁界の印加は、熱処理を開始するとき、あるいは、結晶化温度に比べて充分に低い温度に加熱される前に開始することが好ましい。本発明の効果を得るためには、非晶質部分の結晶化及び結晶成長が生じるときに磁界を印加しておく必要があるからである。磁界の印加停止は、結晶化が充分に進行してから行う必要がある。結晶化が実質的に完了した後は、冷却工程を開始する前に磁界の印加を停止しても良い。また逆に磁界の印加中に冷却工程を行っても良い。 The application of the magnetic field is preferably started when the heat treatment is started or before it is heated to a temperature sufficiently lower than the crystallization temperature. This is because in order to obtain the effect of the present invention, it is necessary to apply a magnetic field when crystallization and crystal growth of the amorphous portion occur. The application of the magnetic field must be stopped after the crystallization has progressed sufficiently. After the crystallization is substantially completed, application of the magnetic field may be stopped before starting the cooling process. Conversely, the cooling step may be performed during application of the magnetic field.
なお、特許文献５には、全部もしくは一部が非晶質であるＲ−Ｆｅ−Ｂ系急冷合金を磁界中で熱処理することにより、熱処理温度が低く、パルス着磁が不要な熱処理方法を得ることができると記載されている。しかしながら、この方法では、熱処理前の急冷合金の組織（結晶粒径、結晶相の体積比率）を規定していないので、均一微細な組織の磁石が得られるかどうかは不明である。 Patent Document 5 discloses a heat treatment method in which a heat treatment temperature is low and pulse magnetization is unnecessary by heat-treating all or part of an amorphous R-Fe-B-based quenched alloy in a magnetic field. It is described that it can. However, this method does not define the structure of the quenched alloy before heat treatment (crystal grain size, volume ratio of crystal phase), so it is unclear whether a magnet with a uniform fine structure can be obtained.
また、従来、急冷合金を磁界中で熱処理することにより、異方性磁石を作製しようとすることが試みられており、特許文献６、７などに開示されている。しかしながら、これらは全て合金を異方化させるための処理である。熱処理前の急冷合金はアモルファスが必須もしくは前提になっている。アモルファスの状態から結晶核を生成させるには大きなエネルギーが必要であるため、核が生成するとそれが一気に成長してしまう。発明者らの実験によると、アモルファスを熱処理した場合、磁界の有無に依らず最終的に得られる熱処理後の組織は粗大な粒を含んでおり、磁界によって磁石組織が均一微細になる効果はほとんど見られなかった。 Conventionally, an attempt has been made to produce an anisotropic magnet by heat-treating a quenched alloy in a magnetic field, which is disclosed in Patent Documents 6 and 7 and the like. However, these are all treatments for making the alloy anisotropic. An amorphous alloy is essential or presupposed for the quenched alloy before the heat treatment. Since a large amount of energy is required to generate crystal nuclei from an amorphous state, when nuclei are generated, they grow at once. According to the experiments by the inventors, when the amorphous is heat-treated, the structure after the heat treatment finally obtained regardless of the presence or absence of the magnetic field contains coarse grains, and the magnetic structure has almost no effect due to the magnetic field. I couldn't see it.
〈磁石組織〉
本発明によれば、Ｒ2Ｆｅ14Ｂ相の平均結晶粒径が５０ｎｍ以下、結晶粒径の標準偏差が５ｎｍ以上２０ｎｍ以下の極めて均一微細な結晶組織の磁石が得られる。
<Magnetic structure>
According to the present invention, it is possible to obtain a magnet having an extremely uniform crystal structure in which the average crystal grain size of the R 2 Fe 14 B phase is 50 nm or less and the standard deviation of the crystal grain size is 5 nm to 20 nm.
また、前述したように、ナノコンポジット磁石のための組成範囲を選択した場合は、上記の熱処理により、Ｒ2Ｆｅ14Ｂ相のみならず、鉄基硼化物やα−Ｆｅなどの軟磁性相の均一微細に分散した金属組織を有する、優れた特性を示すナノコンポジット磁石が得られる。 In addition, as described above, when the composition range for the nanocomposite magnet is selected, not only the R 2 Fe 14 B phase but also the soft magnetic phase such as iron-based boride and α-Fe can be obtained by the above heat treatment. A nanocomposite magnet having a uniform and finely dispersed metal structure and exhibiting excellent characteristics can be obtained.
〈実施例１〉
Ｎｄ9.0Ｆｅ73.0Ｂ12.6Ｃ1.4Ｔｉ3.0Ｎｂ1.0の組成を有する合金を総量が１０ｇとなるように秤量し、メルトスピニング装置の石英坩堝内に投入した。圧力１．３３〜４７．９２ｋＰａのＡｒ雰囲気中において、合金を高周波加熱によって溶解した。溶湯温度が１３５０℃に達した後、溶湯の湯面をＡｒガスによって加圧し、オリフィスから溶湯を噴射した。噴射された溶湯は、室温にて９ｍ／秒のロール表面速度にて回転する純銅製の冷却ロールの外周面に接触し、急冷され、薄帯状に凝固した。得られた急冷合金の幅は２ｍｍ、厚さは４０μｍであった。また、得られた急冷合金の結晶組織をＴＥＭで観察したところ、平均結晶粒径が３０ｎｍ以下の結晶相が体積比率で２０％存在していた。
<Example 1>
An alloy having a composition of Nd 9.0 Fe 73.0 B 12.6 C 1.4 Ti 3.0 Nb 1.0 was weighed so that the total amount would be 10 g and put into a quartz crucible of a melt spinning apparatus. The alloy was melted by high frequency heating in an Ar atmosphere at a pressure of 1.33 to 47.92 kPa. After the molten metal temperature reached 1350 ° C., the molten metal surface was pressurized with Ar gas, and the molten metal was injected from the orifice. The injected molten metal was brought into contact with the outer peripheral surface of a pure copper cooling roll rotating at a roll surface speed of 9 m / second at room temperature, rapidly cooled, and solidified into a thin strip. The obtained quenched alloy had a width of 2 mm and a thickness of 40 μm. Further, when the crystal structure of the obtained quenched alloy was observed with a TEM, a crystal phase having an average crystal grain size of 30 nm or less was present in a volume ratio of 20%.
次に、上記の方法によって作製された急冷凝固合金を、１０Ｔの磁界中、Ａｒ雰囲気中において、７４０℃の熱処理温度域で６分間保持し、その後、室温まで冷却した。熱処理工程における昇温速度は１０Ｋ／ｓ程度、降温速度は１００Ｋ／ｓ程度であった。透過電子顕微鏡（ＴＥＭ）により、得られた磁石の結晶組織を観察したところ、平均結晶粒径が５０ｎｍ以下、結晶粒径の標準偏差が２０ｎｍの極めて均一微細な組織であった。観察結果を図１に示す。 Next, the rapidly solidified alloy produced by the above method was kept in a 10 T magnetic field in an Ar atmosphere in a heat treatment temperature range of 740 ° C. for 6 minutes, and then cooled to room temperature. The rate of temperature increase in the heat treatment step was about 10 K / s, and the rate of temperature decrease was about 100 K / s. When the crystal structure of the obtained magnet was observed with a transmission electron microscope (TEM), it was a very uniform and fine structure with an average crystal grain size of 50 nm or less and a standard deviation of the crystal grain size of 20 nm. The observation results are shown in FIG.
得られた磁石は、Ｒ2Ｆｅ14Ｂ相（硬磁性相）と鉄基硼化物相（軟磁性相）とが磁気的に結合したナノコンポジット磁石であり、平均結晶粒径が５０ｎｍ以下、結晶粒径の標準偏差が２０ｎｍであった。 The obtained magnet is a nanocomposite magnet in which an R 2 Fe 14 B phase (hard magnetic phase) and an iron-based boride phase (soft magnetic phase) are magnetically coupled, with an average crystal grain size of 50 nm or less, The standard deviation of the particle size was 20 nm.
なお、熱処理中に印加する磁界が１Ｔでも、均一微細化の効果は充分に達成された。これは、本実施例が軟磁性相を含むナノコンポジット磁石であったためであると考えられ、単相磁石の場合は、２Ｔ以上の磁界を印加することが好ましいと考えられる。 Even when the magnetic field applied during the heat treatment was 1 T, the effect of uniform miniaturization was sufficiently achieved. This is considered to be because this example was a nanocomposite magnet containing a soft magnetic phase. In the case of a single-phase magnet, it is considered preferable to apply a magnetic field of 2T or more.
〈比較例１〉
熱処理時に磁界を印加しなかったことを除いて実施例１と同様の方法で磁石を作製した。得られた磁石の結晶組織を観察したところ、平均結晶粒径が１００ｎｍ以下、結晶粒径の標準偏差が５０ｎｍであった。観察結果を図２に示す。
<Comparative example 1>
A magnet was produced in the same manner as in Example 1 except that no magnetic field was applied during the heat treatment. When the crystal structure of the obtained magnet was observed, the average crystal grain size was 100 nm or less, and the standard deviation of the crystal grain size was 50 nm. The observation results are shown in FIG.
〈比較例２〉
急冷工程においてロール表面速度を１３ｍ／ｓとし、熱処理時に磁界を印加しなかったことを除いて実施例１と同様の方法で磁石を作製した。得られた急冷合金の組織を観察したところ、１００％非晶質であった。また、得られた磁石の結晶組織を観察したところ、平均結晶粒径が１００ｎｍ以下、結晶粒径の標準偏差が５０ｎｍであった。観察結果を図３に示す。
<Comparative example 2>
A magnet was produced in the same manner as in Example 1 except that the roll surface speed was 13 m / s in the rapid cooling step and no magnetic field was applied during the heat treatment. When the structure of the obtained quenched alloy was observed, it was 100% amorphous. Further, when the crystal structure of the obtained magnet was observed, the average crystal grain size was 100 nm or less, and the standard deviation of the crystal grain size was 50 nm. The observation results are shown in FIG.
〈比較例３〉
急冷工程においてロール表面速度を１３ｍ／ｓとしたことを除いて実施例１と同様の方法で磁石を作製した。すなわち、熱処理時には実施例１と同様の磁界を印加した。得られた急冷合金の組織を観察したところ１００％非晶質であった。また、得られた磁石の結晶組織を観察したところ、平均結晶粒径が１００ｎｍ以下、結晶粒径の標準偏差が５０ｎｍであった。観察結果を図４に示す。
<Comparative Example 3>
A magnet was produced in the same manner as in Example 1 except that the roll surface speed was 13 m / s in the rapid cooling step. That is, the same magnetic field as in Example 1 was applied during the heat treatment. When the structure of the obtained quenched alloy was observed, it was 100% amorphous. Further, when the crystal structure of the obtained magnet was observed, the average crystal grain size was 100 nm or less, and the standard deviation of the crystal grain size was 50 nm. The observation results are shown in FIG.
図５は、実施例１および比較例１の磁石について得られた減磁曲線を示すグラフである。これらの磁石について測定された磁気特性値を、以下の表１に示す。 FIG. 5 is a graph showing demagnetization curves obtained for the magnets of Example 1 and Comparative Example 1. The magnetic property values measured for these magnets are shown in Table 1 below.
比較例１に比べ、実施例１では、残留磁束密度Ｂr、固有保磁力ＨcJ、最大磁気エネルギー積（ＢＨ）maxが何れも向上していることがわかる。飽和磁化Ｉsには差異がみられなかったことから、実施例１では金属組織が均一微細化されたことによるレマネンスエンハンスメントの効果を確認できた。 Compared to Comparative Example 1, it can be seen that in Example 1, the residual magnetic flux density B r , the intrinsic coercive force H cJ , and the maximum magnetic energy product (BH) max are all improved. Since the difference was not observed in the saturation magnetization I s, was confirmed the effect of Le Manet Nsu enhancement due to the metal structure of Example 1 is uniformly fine.
〈実施例２〉
Ｎｄ7.0Ｆｅ83.0Ｂ7.0Ｃ1.0Ｔｉ2.0の組成を有する合金を総量が１０ｇとなるように秤量し、メルトスピニング装置の石英坩堝内に投入した。圧力１．３３〜４７．９２ｋＰａのＡｒ雰囲気中において、合金を高周波加熱によって溶解した。溶湯温度が１３５０℃に達した後、溶湯の湯面をＡｒガスによって加圧し、オリフィスから溶湯を噴射した。噴射された溶湯は、室温にて２０ｍ／秒のロール表面速度にて回転する純銅製の冷却ロールの外周面に接触し、急冷され、薄帯状に凝固した。得られた急冷合金の幅は２ｍｍ、厚さは３０μｍであった。また、得られた急冷合金の結晶組織をＴＥＭで観察したところ、平均結晶粒径が３０ｎｍ以下の結晶相が体積比率で４０％存在していた。
<Example 2>
An alloy having a composition of Nd 7.0 Fe 83.0 B 7.0 C 1.0 Ti 2.0 was weighed so that the total amount became 10 g, and was put into a quartz crucible of a melt spinning apparatus. The alloy was melted by high frequency heating in an Ar atmosphere at a pressure of 1.33 to 47.92 kPa. After the molten metal temperature reached 1350 ° C., the molten metal surface was pressurized with Ar gas, and the molten metal was injected from the orifice. The injected molten metal was contacted with the outer peripheral surface of a pure copper cooling roll rotating at a roll surface speed of 20 m / sec at room temperature, quenched, and solidified into a thin strip. The obtained quenched alloy had a width of 2 mm and a thickness of 30 μm. Further, when the crystal structure of the obtained quenched alloy was observed with a TEM, a crystal phase having an average crystal grain size of 30 nm or less was present in a volume ratio of 40%.
次に、上記の方法によって作製された急冷凝固合金を、８Ｔの磁界中、Ａｒ雰囲気中において、７００℃の熱処理温度域で６分間保持し、その後、室温まで冷却した。熱処理工程における昇温速度は１０℃／ｓ程度、降温速度は１００℃／ｓ程度であった。ＴＥＭにより、得られた磁石の結晶組織を観察したところ、平均結晶粒径が５０ｎｍ以下、結晶粒径の標準偏差が２０ｎｍの極めて均一微細な組織であった。 Next, the rapidly solidified alloy produced by the above-described method was held in a heat treatment temperature range of 700 ° C. for 6 minutes in an Ar atmosphere in an 8T magnetic field, and then cooled to room temperature. The temperature increase rate in the heat treatment step was about 10 ° C./s, and the temperature decrease rate was about 100 ° C./s. When the crystal structure of the obtained magnet was observed by TEM, it was a very uniform and fine structure with an average crystal grain size of 50 nm or less and a standard deviation of crystal grain size of 20 nm.
得られた磁石は、Ｒ2Ｆｅ14Ｂ相（硬磁性相）とα−Ｆｅ相（軟磁性相）とが磁気的に結合したナノコンポジット磁石であった。なお、熱処理中に印加する磁界が１Ｔでも、均一微細化の効果は充分に達成されることを確認した。 The obtained magnet was a nanocomposite magnet in which an R 2 Fe 14 B phase (hard magnetic phase) and an α-Fe phase (soft magnetic phase) were magnetically coupled. It was confirmed that the effect of uniform miniaturization was sufficiently achieved even when the magnetic field applied during the heat treatment was 1T.
〈比較例４〉
熱処理時に磁界を印加しなかったことを除いて実施例２と同様の方法で磁石を作製した。得られた磁石の結晶組織を観察したところ、平均結晶粒径が８０ｎｍ以下、結晶粒径の標準偏差が４０ｎｍであった。
<Comparative example 4>
A magnet was produced in the same manner as in Example 2 except that no magnetic field was applied during the heat treatment. When the crystal structure of the obtained magnet was observed, the average crystal grain size was 80 nm or less, and the standard deviation of the crystal grain size was 40 nm.
図６は、実施例２および比較例４の磁石について得られた減磁曲線を示すグラフである。これらの磁石について測定された磁気特性値を以下の表２に示す。 FIG. 6 is a graph showing demagnetization curves obtained for the magnets of Example 2 and Comparative Example 4. The magnetic property values measured for these magnets are shown in Table 2 below.
軟磁性相としてα−Ｆｅ相を含有するナノコンポジット磁石を作製する場合、軟磁性相と硬磁性相とが均一かつ微細に分散する効果に加え、軟磁性相であるα−Ｆｅ相の体積率を向上させる効果があるため、両方の効果によって磁気特性が大きく向上する。 When producing a nanocomposite magnet containing an α-Fe phase as a soft magnetic phase, in addition to the effect of uniformly and finely dispersing the soft magnetic phase and the hard magnetic phase, the volume fraction of the α-Fe phase that is the soft magnetic phase Therefore, the magnetic characteristics are greatly improved by both effects.
図７は、実施例２および比較例４の薄帯の粉砕粉についてＸＲＤ測定を行った結果を示すグラフである。得られたＸＲＤパターンによると、α−Ｆｅ相の回折ピーク強度は、比較例４よりも実施例２で大きい。このことからも、本発明ではα−Ｆｅ相の体積率が向上していると推測できる。 FIG. 7 is a graph showing the results of XRD measurement performed on the pulverized thin ribbons of Example 2 and Comparative Example 4. According to the obtained XRD pattern, the diffraction peak intensity of the α-Fe phase is higher in Example 2 than in Comparative Example 4. From this, it can be estimated that the volume ratio of the α-Fe phase is improved in the present invention.
本発明の製造方法によれば、組織が均一に微細化され、優れた磁石特性を有する等方性鉄基希土類磁石が得られ、様々な用途に利用され得る。 According to the production method of the present invention, an isotropic iron-based rare earth magnet having a finely structured structure and excellent magnetic properties can be obtained and used for various applications.
Claims (7)
前記合金の溶湯を急冷することにより、平均結晶粒径５０ｎｍ以下のＮｄ2Ｆｅ14Ｂ型化合物相が体積比率で全体の５％以上５０％以下存在する急冷合金を作製する冷却工程と、
前記急冷合金に対して、磁界中でＮｄ2Ｆｅ14Ｂ型化合物相の結晶化温度以上の温度を保持する熱処理工程と、
を含む、等方性鉄基希土類合金磁石の製造方法。 Composition formula is represented by (Fe 1-m T m) 100-xyz (B 1-p C p) x R y M z, T is one or more elements selected from the group consisting of Co and Ni, R is One or more elements selected from the group consisting of yttrium and rare earth metal elements, M is Ti, Zr, Al, Si, V, Mn, Cu, Zn, Ga, Cr, Nb, Mo, Ag, Hf, Ta, One or more elements selected from the group consisting of W, Pt, Au, Pb, Bi, Sn, 4 ≦ x ≦ 20, 4 ≦ y ≦ 20, 0.1 ≦ z ≦ 5, 0 ≦ m ≦ Producing a molten alloy satisfying the relationship of 0.8, 0 <p ≦ 0.3;
A cooling step of rapidly quenching the molten alloy to produce a quenched alloy in which an Nd 2 Fe 14 B type compound phase having an average crystal grain size of 50 nm or less is present in a volume ratio of 5% or more and 50% or less;
A heat treatment step of maintaining a temperature equal to or higher than a crystallization temperature of the Nd 2 Fe 14 B type compound phase in a magnetic field with respect to the quenched alloy;
A method for producing an isotropic iron-based rare earth alloy magnet, comprising:
前記熱処理工程により、平均結晶粒径が５ｎｍ以上３０ｎｍ以下の鉄基硼化物相と前記Ｎｄ2Ｆｅ14Ｂ型化合物相とが混在するナノコンポジット組織を形成する、請求項１から５のいずれかに記載の鉄基希土類合金磁石の製造方法。 10 ≦ x ≦ 16, 6 ≦ y ≦ 10 is satisfied, M contains Ti as an essential element,
6. The nanocomposite structure in which an iron-based boride phase having an average crystal grain size of 5 nm to 30 nm and the Nd 2 Fe 14 B-type compound phase are mixed is formed by the heat treatment step. The manufacturing method of the iron-based rare earth alloy magnet of description.
前記熱処理工程により、平均結晶粒径が５ｎｍ以上３０ｎｍ以下のα−Ｆｅ相と前記Ｎｄ2Ｆｅ14Ｂ型化合物相とが混在するナノコンポジット組織を形成する、請求項１から５のいずれかに記載の鉄基希土類合金磁石の製造方法。 4 ≦ x ≦ 8, 6 ≦ y ≦ 10 is satisfied, M contains Ti as an essential element,
6. The nanocomposite structure in which an α-Fe phase having an average crystal grain size of 5 nm to 30 nm and the Nd 2 Fe 14 B type compound phase are mixed is formed by the heat treatment step. Of manufacturing iron-based rare earth alloy magnets.
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| WO2010113482A1 (en) * | 2009-03-31 | 2010-10-07 | 日立金属株式会社 | Nanocomposite bulk magnet and process for producing same |
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| JP2020136668A (en) * | 2019-02-19 | 2020-08-31 | 有研稀土新材料股▲フン▼有限公司 | Yttrium-added rare-earth permanent magnetic material and preparation method thereof |
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| WO2010113482A1 (en) * | 2009-03-31 | 2010-10-07 | 日立金属株式会社 | Nanocomposite bulk magnet and process for producing same |
| JP4591633B2 (en) * | 2009-03-31 | 2010-12-01 | 日立金属株式会社 | Nanocomposite bulk magnet and method for producing the same |
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| JP2020522143A (en) * | 2018-04-09 | 2020-07-27 | 有研稀土新材料股▲フン▼有限公司 | Yttrium-added rare earth permanent magnet material and its manufacturing method |
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| JP2020136668A (en) * | 2019-02-19 | 2020-08-31 | 有研稀土新材料股▲フン▼有限公司 | Yttrium-added rare-earth permanent magnetic material and preparation method thereof |
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