JP7035682B2 - RTB-based sintered magnet - Google Patents

RTB-based sintered magnet Download PDF

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JP7035682B2
JP7035682B2 JP2018055192A JP2018055192A JP7035682B2 JP 7035682 B2 JP7035682 B2 JP 7035682B2 JP 2018055192 A JP2018055192 A JP 2018055192A JP 2018055192 A JP2018055192 A JP 2018055192A JP 7035682 B2 JP7035682 B2 JP 7035682B2
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佳則 藤川
将史 三輪
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TDK Corp
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本発明は、Ｒ－Ｔ－Ｂ系焼結磁石に関する。 The present invention relates to an RTB-based sintered magnet.

特許文献１に示されるように、Ｒ－Ｔ－Ｂ系焼結磁石は、優れた磁気特性を有することが知られている。現在では、さらなる磁気特性の向上が望まれている。 As shown in Patent Document 1, RTB-based sintered magnets are known to have excellent magnetic properties. At present, further improvement in magnetic properties is desired.

Ｒ－Ｔ－Ｂ系焼結磁石の磁気特性、特に保磁力を向上させる方法には、原料合金を作製する段階でＲとして重希土類元素を含ませる方法（一合金法）が知られている。また、重希土類元素を含まない主相系合金と重希土類元素を含む粒界相系合金とを粉砕後に混合して焼結する方法（二合金法）がある。さらに、特許文献２に記載されているように、Ｒ－Ｔ－Ｂ系焼結磁石を作製した後に、表面に重希土類元素を付着させて加熱することにより、粒界を通じて重希土類元素を拡散させる方法（粒界拡散法）がある。 As a method for improving the magnetic properties of the RTB-based sintered magnet, particularly the coercive force, a method of incorporating a heavy rare earth element as R at the stage of producing a raw material alloy (one alloy method) is known. Further, there is a method (dual alloy method) in which a main phase alloy containing no heavy rare earth element and a grain boundary phase alloy containing a heavy rare earth element are crushed and then mixed and sintered. Further, as described in Patent Document 2, after the RTB-based sintered magnet is manufactured, the heavy rare earth element is adhered to the surface and heated to diffuse the heavy rare earth element through the grain boundaries. There is a method (grain boundary diffusion method).

上記の一合金法は主相粒子中に重希土類元素が存在するため、最大エネルギー積が低下してしまう場合がある。二合金法では主相粒子中の重希土類元素を低減でき、最大エネルギー積の低下を抑制することができる。粒界拡散法では、主相粒子のうち粒界にごく近い領域のみ重希土類元素の濃度を高くでき、主相粒子内部の重希土類元素の濃度を低減できる。すなわち、一般的なコアシェル構造の主相粒子を得ることができる。一般的なコアシェル構造とは、コア部の重希土類元素の濃度がコア部を被覆するシェル部の重希土類元素の濃度よりも低い構造のことである。これにより、二合金法と比べて保磁力を高くし、最大エネルギー積の低下を抑制できる。さらに、高価な重希土類元素の使用量を抑制できる。 In the above one alloy method, the maximum energy product may decrease because heavy rare earth elements are present in the main phase particles. In the two-alloy method, heavy rare earth elements in the main phase particles can be reduced, and a decrease in the maximum energy product can be suppressed. In the grain boundary diffusion method, the concentration of heavy rare earth elements can be increased only in the region very close to the grain boundaries of the main phase particles, and the concentration of heavy rare earth elements inside the main phase particles can be reduced. That is, it is possible to obtain main phase particles having a general core-shell structure. The general core-shell structure is a structure in which the concentration of the heavy rare earth element in the core portion is lower than the concentration of the heavy rare earth element in the shell portion covering the core portion. As a result, the coercive force can be increased as compared with the two-alloy method, and the decrease in the maximum energy product can be suppressed. Furthermore, the amount of expensive heavy rare earth elements used can be suppressed.

また、特許文献３には、従来のＲ－Ｔ－Ｂ系焼結磁石よりも保磁力を向上させるために、コア部の重希土類元素の濃度がシェル部の重希土類元素の濃度よりも高い主相粒子を含む技術が記載されている。 Further, in Patent Document 3, in order to improve the coercive force as compared with the conventional RTB-based sintered magnet, the concentration of the heavy rare earth element in the core portion is higher than the concentration of the heavy rare earth element in the shell portion. Techniques involving phase particles are described.

特開昭５９－４６００８号公報Japanese Unexamined Patent Publication No. 59-4608 国際公開第２００６／０４３３４８号International Publication No. 2006/0433348 特開２０１６－１５４２１９号公報Japanese Unexamined Patent Publication No. 2016-154219

しかし、現在では、さらなる保磁力の向上およびコストの低減が求められている。 However, at present, further improvement of coercive force and cost reduction are required.

本発明は、磁気特性を向上させ、かつ、低コストであるＲ－Ｔ－Ｂ系焼結磁石を得ることを目的とする。 An object of the present invention is to obtain an RTB-based sintered magnet having improved magnetic properties and low cost.

上記の目的を達成するために、本発明に係るＲ－Ｔ－Ｂ系焼結磁石は、
Ｒ２Ｔ１４Ｂ結晶からなる主相粒子を含むＲ－Ｔ－Ｂ系焼結磁石であって、
Ｒは重希土類元素ＲＨを必須とする１種以上の希土類元素、ＴはＦｅまたはＦｅおよびＣｏを必須とする１種以上の遷移金属元素、Ｂはホウ素であり、
前記主相粒子の一部が逆コアシェル主相粒子であり、
前記逆コアシェル主相粒子は、コア部およびシェル部を有し、
前記コア部における全ＲＨ濃度（ａｔ％）をＣＲＣ、
前記シェル部における全ＲＨ濃度（ａｔ％）をＣＲＳとした場合に、
ＣＲＣ／ＣＲＳ＞１．０であり、
前記逆コアシェル主相粒子の存在比率が、磁石中央部よりも磁石表層部の方が大きいことを特徴とする。 In order to achieve the above object, the RTB-based sintered magnet according to the present invention is
An RTB-based sintered magnet containing main phase particles composed of R 2 T 14 B crystals.
R is one or more rare earth elements that require the heavy rare earth element RH, T is one or more transition metal elements that require Fe or Fe and Co, and B is boron.
Some of the main phase particles are reverse core shell main phase particles.
The reverse core-shell main phase particles have a core portion and a shell portion, and have a core portion and a shell portion.
The total RH concentration (at%) in the core portion is C RC ,
When the total RH concentration (at%) in the shell portion is CRS ,
C RC / C RS > 1.0,
The abundance ratio of the reverse core shell main phase particles is characterized in that the magnet surface layer portion is larger than the magnet central portion.

本発明に係るＲ－Ｔ－Ｂ系焼結磁石は、上記の特徴を有することにより、磁気特性を向上させ、かつ、低コストな磁石となる。 The RTB-based sintered magnet according to the present invention has the above-mentioned characteristics, and thus has improved magnetic characteristics and is a low-cost magnet.

本発明に係るＲ－Ｔ－Ｂ系焼結磁石は、ＣＲＣ／ＣＲＳ＞１．５であってもよい。 The RTB-based sintered magnet according to the present invention may have C RC / C RS > 1.5.

本発明に係るＲ－Ｔ－Ｂ系焼結磁石は、
前記主相粒子の一部がコアシェル主相粒子であり、
前記コアシェル主相粒子は、コア部およびシェル部を有し、
前記コア部における全ＲＨ濃度（ａｔ％）をＣＮＣ、
前記シェル部における全ＲＨ濃度（ａｔ％）をＣＮＳとした場合に、
ＣＮＣ／ＣＮＳ＜１．０であってもよい。 The RTB-based sintered magnet according to the present invention is
Some of the main phase particles are core shell main phase particles.
The core-shell main phase particles have a core portion and a shell portion, and have a core portion and a shell portion.
The total RH concentration (at%) in the core part is CNC ,
When the total RH concentration (at%) in the shell portion is CNS ,
It may be C NC / C NS <1.0.

本発明に係るＲ－Ｔ－Ｂ系焼結磁石は、
主に前記コアシェル主相粒子からなるコアシェル粒子層、および、主に前記逆コアシェル主相粒子からなる逆コアシェル粒子層を含んでいてもよい。 The RTB-based sintered magnet according to the present invention is
It may contain a core-shell particle layer mainly composed of the core-shell main phase particles and a reverse core-shell particle layer mainly composed of the reverse core-shell main phase particles.

本発明に係るＲ－Ｔ－Ｂ系焼結磁石は、
磁石中央部から磁石表層部に向かって、前記コアシェル粒子層および前記逆コアシェル粒子層がこの順番に並んでいてもよい。 The RTB-based sintered magnet according to the present invention is
The core-shell particle layer and the reverse core-shell particle layer may be arranged in this order from the central portion of the magnet toward the surface layer portion of the magnet.

本発明に係るＲ－Ｔ－Ｂ系焼結磁石は、
前記主相粒子の一部がコアシェル構造を有さない非コアシェル主相粒子であって、主に前記非コアシェル主相粒子からなる非コアシェル粒子層を含むＲ－Ｔ－Ｂ系焼結磁石であって、
磁石中央部から磁石表層部に向かって、前記非コアシェル粒子層、前記コアシェル粒子層および前記逆コアシェル粒子層がこの順番に並んでいてもよい。 The RTB-based sintered magnet according to the present invention is
A part of the main phase particles is a non-core shell main phase particle having no core shell structure, and is an RTB-based sintered magnet containing a non-core shell particle layer mainly composed of the non-core shell main phase particles. hand,
The non-core shell particle layer, the core shell particle layer, and the reverse core shell particle layer may be arranged in this order from the central portion of the magnet to the surface layer portion of the magnet.

本発明の一実施形態に係るＲ－Ｔ－Ｂ系焼結磁石の断面の概略図である。It is the schematic of the cross section of the RTB system sintered magnet which concerns on one Embodiment of this invention. 本発明の一実施形態に係るＲ－Ｔ－Ｂ系焼結磁石の断面の概略図である。It is the schematic of the cross section of the RTB system sintered magnet which concerns on one Embodiment of this invention. 本発明の一実施形態に係るＲ－Ｔ－Ｂ系焼結磁石の磁石表層部付近の断面の概略図である。It is the schematic of the cross section in the vicinity of the magnet surface layer part of the RTB system sintered magnet which concerns on one Embodiment of this invention.

以下、本発明を、図面に示す実施形態に基づき説明する。 Hereinafter, the present invention will be described based on the embodiments shown in the drawings.

＜Ｒ－Ｔ－Ｂ系焼結磁石＞ <RTB-based sintered magnet>

本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石１は、Ｒ２Ｔ１４Ｂ結晶からなる主相粒子を含む。Ｒは重希土類元素ＲＨを必須とする１種以上の希土類元素、ＴはＦｅまたはＦｅおよびＣｏを必須とする１種以上の遷移金属元素、Ｂはホウ素である。さらに、Ｚｒを含んでもよい。なお、Ｒとして含まれる希土類元素とは、長周期型周期表の第３族に属するＳｃとＹとランタノイド元素とのことをいう。また、重希土類元素ＲＨとは、Ｇｄ，Ｔｂ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ，Ｌｕのことをいう。 The RTB-based sintered magnet 1 according to the present embodiment contains main phase particles composed of R2 T 14 B crystals. R is one or more rare earth elements that require the heavy rare earth element RH, T is one or more transition metal elements that require Fe or Fe and Co, and B is boron. Further, Zr may be contained. The rare earth element contained as R means Sc, Y, and a lanthanoid element belonging to Group 3 of the long-periodic table. The heavy rare earth element RH refers to Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

Ｒの含有量には特に制限はないが、２５質量％以上３５質量％以下であってもよく、好ましくは２８質量％以上３３質量％以下である。Ｒの含有量が２５質量％以上であると、Ｒ－Ｔ－Ｂ系焼結磁石１の主相粒子となるＲ２Ｔ１４Ｂ結晶の生成が十分に行われやすく、軟磁性を持つα－Ｆｅなどの析出を抑制し、磁気特性の低下を抑制しやすくなる。 Ｒの含有量が３５質量％以下であると、Ｒ－Ｔ－Ｂ系焼結磁石１の残留磁束密度Ｂｒが向上する傾向にある。 The content of R is not particularly limited, but may be 25% by mass or more and 35% by mass or less, preferably 28% by mass or more and 33% by mass or less. When the R content is 25% by mass or more, R2 T 14 B crystals, which are the main phase particles of the R-TB system sintered magnet 1, are sufficiently easily generated, and α- with soft magnetism is easily generated. It suppresses the precipitation of Fe and the like, and it becomes easy to suppress the deterioration of the magnetic characteristics. When the R content is 35% by mass or less, the residual magnetic flux density Br of the RTB-based sintered magnet 1 tends to improve.

本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石におけるＢの含有量は、０．５質量％以上１．５質量％以下であってもよく、好ましくは０．８質量％以上１．２質量％以下であり、より好ましくは０．８質量％以上１．０質量％以下である。Ｂの含有量が０．５質量％以上であることにより保磁力Ｈｃｊが向上する傾向にある。また、Ｂの含有量が１．５質量％以下であることにより、残留磁束密度Ｂｒが向上する傾向にある。 The content of B in the RTB-based sintered magnet according to the present embodiment may be 0.5% by mass or more and 1.5% by mass or less, preferably 0.8% by mass or more and 1.2. It is 0% by mass or less, more preferably 0.8% by mass or more and 1.0% by mass or less. When the content of B is 0.5% by mass or more, the coercive force Hcj tends to be improved. Further, when the content of B is 1.5% by mass or less, the residual magnetic flux density Br tends to be improved.

Ｔは、Ｆｅ単独であってもよく、Ｆｅの一部がＣｏで置換されていてもよい。本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石におけるＦｅの含有量は、Ｒ－Ｔ－Ｂ系焼結磁石において不可避的不純物，Ｏ，ＣおよびＮを除いた場合の実質的な残部である。Ｃｏの含有量は０質量％以上４質量％以下であることが好ましく、０．１質量％以上２質量％以下であることがより好ましく、０．３質量％以上１．５質量％以下とすることが更に好ましい。ＦｅまたはＦｅ及びＣｏ以外の遷移金属元素としては、特に限定はないが、例えば、Ｔｉ，Ｖ，Ｃｒ，Ｍｎ，Ｎｉ，Ｃｕ，Ｚｒ，Ｎｂ，Ｍｏ，Ｈｆ，Ｔａ，Ｗなどが挙げられる。また、Ｔとして含まれる遷移金属元素の一部を、例えば、Ａｌ，Ｇａ，Ｓｉ，Ｂｉ，Ｓｎなどの元素に置換してもよい。 T may be Fe alone, or a part of Fe may be replaced with Co. The Fe content in the RTB-based sintered magnet according to the present embodiment is a substantial balance when the unavoidable impurities, O, C and N are removed in the RTB-based sintered magnet. be. The Co content is preferably 0% by mass or more and 4% by mass or less, more preferably 0.1% by mass or more and 2% by mass or less, and 0.3% by mass or more and 1.5% by mass or less. Is even more preferable. The transition metal element other than Fe or Fe and Co is not particularly limited, and examples thereof include Ti, V, Cr, Mn, Ni, Cu, Zr, Nb, Mo, Hf, Ta, and W. Further, a part of the transition metal element contained as T may be replaced with an element such as Al, Ga, Si, Bi, Sn.

Ｒ－Ｔ－Ｂ系焼結磁石１がＡｌおよびＣｕから選択される１種または２種を含有する場合、Ａｌ、Ｃｕから選択される１種または２種の含有量は、それぞれ０．０２質量％以上０．６０質量％以下とすることが好ましい。ＡｌおよびＣｕから選択される１種または２種を、それぞれ０．０２質量％以上０．６０質量％以下、含有することにより、Ｒ－Ｔ－Ｂ系焼結磁石１の保磁力および耐湿性が向上し、温度特性が改善される傾向にある。Ａｌの含有量は０．０３質量％以上０．４０質量％以下が好ましく、０．０５質量％以上０．２５質量％以下がより好ましい。また、Ｃｕの含有量は０質量％超０．３０質量％以下が好ましく、０質量％超０．２０質量％以下がより好ましく、０．０３質量％以上０．１５質量％以下が更に好ましい。 When the RTB-based sintered magnet 1 contains one or two types selected from Al and Cu, the content of one or two types selected from Al and Cu is 0.02 mass, respectively. It is preferably% or more and 0.60% by mass or less. By containing 1 or 2 types selected from Al and Cu in an amount of 0.02% by mass or more and 0.60% by mass or less, respectively, the coercive force and moisture resistance of the RTB-based sintered magnet 1 can be improved. It tends to improve and the temperature characteristics are improved. The Al content is preferably 0.03% by mass or more and 0.40% by mass or less, and more preferably 0.05% by mass or more and 0.25% by mass or less. The Cu content is preferably more than 0% by mass and 0.30% by mass or less, more preferably more than 0% by mass and 0.20% by mass or less, and further preferably 0.03% by mass or more and 0.15% by mass or less.

Ｒ－Ｔ－Ｂ系焼結磁石１は、さらにＺｒを含むことができる。Ｚｒの含有量は、０質量％超０．２５質量％以下であってもよい。Ｚｒを上記の範囲内で含有することにより、焼結磁石の製造過程、主に焼結工程において、主相粒子の異常成長を抑制することができる。そのため、得られる焼結体（Ｒ－Ｔ－Ｂ系焼結磁石１）の組織が均一且つ微細となり、得られる焼結体の磁気特性が向上する傾向にある。上記の効果をより良好に得るために、Ｚｒの含有量は、０．０３質量％以上０．２５質量％以下であってもよい。 The RTB-based sintered magnet 1 can further include Zr. The content of Zr may be more than 0% by mass and 0.25% by mass or less. By containing Zr within the above range, abnormal growth of main phase particles can be suppressed in the manufacturing process of the sintered magnet, mainly in the sintering process. Therefore, the structure of the obtained sintered body (RTB-based sintered magnet 1) tends to be uniform and fine, and the magnetic properties of the obtained sintered body tend to be improved. In order to obtain the above effects better, the Zr content may be 0.03% by mass or more and 0.25% by mass or less.

また、Ｒ－Ｔ－Ｂ系焼結磁石１におけるＣの含有量は、０．０５質量％以上０．３０質量％以下が好ましい。Ｃの含有量を０．０５質量％以上とすることで、保磁力が向上する傾向にある。Ｃの含有量を０．３０質量％以下とすることで、保磁力（Ｈｃｊ）と、角形比（Ｈｋ／Ｈｃｊ）が十分に高くなる傾向にある。Ｈｋとは、磁気ヒステリシスループ（４πＩ－Ｈカーブ）の第２象限における磁化が残留磁束密度（Ｂｒ）の９０％となるときの磁界強度のことである。角形比は、外部磁界の作用や温度上昇による減磁のし易さを表すパラメータである。角形比が小さい場合には、外部磁界の作用や温度上昇による減磁が大きくなる。また、着磁に要する磁界強度が増大する。保磁力及び角形比をより良好に得るためには、Ｃの含有量を０．１０質量％以上０．２５質量％以下とすることが好ましい。 The content of C in the RTB-based sintered magnet 1 is preferably 0.05% by mass or more and 0.30% by mass or less. By setting the C content to 0.05% by mass or more, the coercive force tends to be improved. By setting the C content to 0.30% by mass or less, the coercive force (Hcj) and the square ratio (Hk / Hcj) tend to be sufficiently high. Hk is the magnetic field strength when the magnetization in the second quadrant of the magnetic hysteresis loop (4πI—H curve) becomes 90% of the residual magnetic flux density (Br). The square ratio is a parameter that indicates the ease of demagnetization due to the action of an external magnetic field or an increase in temperature. When the square ratio is small, the demagnetization due to the action of an external magnetic field and the temperature rise becomes large. In addition, the magnetic field strength required for magnetism increases. In order to obtain a better coercive force and square ratio, the C content is preferably 0.10% by mass or more and 0.25% by mass or less.

また、Ｒ－Ｔ－Ｂ系焼結磁石１におけるＯの含有量は、０．０３質量％以上０．４０質量％以下が好ましい。Ｏの含有量を０．０３質量％以上とすることで、耐食性が向上する傾向にある。０．４０質量％以下とすることで、焼結時に液相が十分に形成されやすくなり、保磁力が向上する傾向にある。耐食性および保磁力をより良好にするために、Ｏの含有量は、０．０５質量％以上０．３０質量％以下としてもよく、０．０５質量％以上０．２５質量％以下としてもよい。 The content of O in the RTB-based sintered magnet 1 is preferably 0.03% by mass or more and 0.40% by mass or less. Corrosion resistance tends to be improved by setting the O content to 0.03% by mass or more. When the content is 0.40% by mass or less, the liquid phase is likely to be sufficiently formed at the time of sintering, and the coercive force tends to be improved. In order to improve the corrosion resistance and the coercive force, the content of O may be 0.05% by mass or more and 0.30% by mass or less, or 0.05% by mass or more and 0.25% by mass or less.

また、Ｒ－Ｔ－Ｂ系焼結磁石１におけるＮの含有量は、０質量％以上０．１５質量％以下であることが好ましい。Ｎの含有量が０．１５質量％以下であることにより、保磁力が十分に向上する傾向にある。 Further, the content of N in the RTB-based sintered magnet 1 is preferably 0% by mass or more and 0.15% by mass or less. When the content of N is 0.15% by mass or less, the coercive force tends to be sufficiently improved.

Ｒ－Ｔ－Ｂ系焼結磁石１は、Ｍｎ，Ｃａ，Ｎｉ，Ｃｌ，Ｓ，Ｆ等の不可避的不純物を、０．００１質量％以上０．５質量％以下程度含んでいてもよい。 The RTB-based sintered magnet 1 may contain unavoidable impurities such as Mn, Ca, Ni, Cl, S, and F in an amount of 0.001% by mass or more and 0.5% by mass or less.

Ｒ－Ｔ－Ｂ系焼結磁石中の酸素量、炭素量、窒素量の測定方法は、従来から一般的に知られている方法を用いることができる。酸素量は、例えば、不活性ガス融解－非分散型赤外線吸収法により測定され、炭素量は、例えば、酸素気流中燃焼－赤外線吸収法により測定され、窒素量は、例えば、不活性ガス融解－熱伝導度法により測定される。 As a method for measuring the amount of oxygen, the amount of carbon, and the amount of nitrogen in the RTB-based sintered magnet, a conventionally known method can be used. The amount of oxygen is measured by, for example, inert gas melting-non-dispersive infrared absorption method, the carbon amount is measured by, for example, combustion in an oxygen stream-infrared absorption method, and the amount of nitrogen is, for example, inert gas melting-. It is measured by the thermal conductivity method.

Ｒ２Ｔ１４Ｂ結晶からなる主相粒子の粒径には特に制限はないが、通常は、１μｍ以上１０μｍ以下である。 The particle size of the main phase particles composed of R 2 T 14 B crystals is not particularly limited, but is usually 1 μm or more and 10 μm or less.

Ｒの種類には特に制限はないが、好ましくはＮｄ，Ｐｒを含む。さらに、重希土類元素ＲＨの種類にも特に制限はないが、好ましくはＤｙおよびＴｂのいずれか一方または両方を含む。 The type of R is not particularly limited, but preferably includes Nd and Pr. Further, the type of the heavy rare earth element RH is not particularly limited, but preferably contains either or both of Dy and Tb.

本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石１は、図１Ａおよび図２に示すように、主に逆コアシェル主相粒子１１からなる逆コアシェル粒子層１ａ、および、主にコアシェル主相粒子１３からなるコアシェル粒子層１ｂを有する。逆コアシェル主相粒子１１およびコアシェル主相粒子１３はＲ２Ｔ１４Ｂ結晶からなる主相粒子である。また、各主相粒子間に粒界１２が存在していてもよい。 As shown in FIGS. 1A and 2, the RTB-based sintered magnet 1 according to the present embodiment has a reverse core shell particle layer 1a mainly composed of reverse core shell main phase particles 11 and a core shell main phase mainly. It has a core-shell particle layer 1b composed of particles 13. The inverted core-shell main phase particles 11 and the core-shell main phase particles 13 are main phase particles composed of R 2 T 14 B crystals. Further, a grain boundary 12 may be present between the main phase particles.

図２に示すように、逆コアシェル主相粒子１１はコア部１１ａおよびコア部１１ａを被覆するシェル部１１ｂを有する。また、コアシェル主相粒子１３はコア部１３ａおよびコア部１３ａを被覆するシェル部１３ｂを有する。なお、各主相粒子がコアシェル構造を有している粒子、すなわち逆コアシェル主相粒子１１またはコアシェル主相粒子１３であることは、ＳＥＭを用いて倍率１０００倍以上１００００倍以下で観察することにより確認できる。 As shown in FIG. 2, the inverted core shell main phase particle 11 has a core portion 11a and a shell portion 11b that covers the core portion 11a. Further, the core-shell main phase particles 13 have a core portion 13a and a shell portion 13b that covers the core portion 13a. The fact that each main phase particle is a particle having a core-shell structure, that is, an inverted core-shell main phase particle 11 or a core-shell main phase particle 13, can be observed by observing using SEM at a magnification of 1000 times or more and 10000 times or less. You can check it.

具体的には、本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石１を切断して得られる断面を鏡面研磨してからＳＥＭで反射電子像を撮影する。反射電子像にて生じる組成コントラストから各主相粒子がコアシェル主相粒子１３であるか逆コアシェル主相粒子１１であるかを判別できる。一般的に、組成コントラストは観察対象の平均原子番号が大きくなるほど明るく（白く）なる。また、重希土類元素ＲＨはその他のＲ－Ｔ－Ｂ系焼結磁石１に含まれる元素と比較して原子番号が大きい。したがって、重希土類元素ＲＨの濃度が相対的に高い領域は重希土類元素ＲＨの濃度が相対的に低い領域と比較して平均原子番号が大きくなる。そして、反射電子像にて主相粒子内部でＲＨ濃度が高い領域はＲＨ濃度が低い領域と比較して明るく（白く）なる。以上より、主相粒子内部で明るい部分の位置によって各主相粒子がコアシェル主相粒子１３であるか逆コアシェル主相粒子１１であるかを判別できる。 Specifically, the cross section obtained by cutting the RTB-based sintered magnet 1 according to the present embodiment is mirror-polished, and then the reflected electron image is photographed by SEM. From the composition contrast generated in the backscattered electron image, it can be determined whether each main phase particle is a core-shell main phase particle 13 or an inverted core-shell main phase particle 11. Generally, the composition contrast becomes brighter (whiter) as the average atomic number of the observation target increases. Further, the heavy rare earth element RH has a larger atomic number than the other elements contained in the RTB-based sintered magnet 1. Therefore, the region where the concentration of the heavy rare earth element RH is relatively high has a larger average atomic number than the region where the concentration of the heavy rare earth element RH is relatively low. Then, in the backscattered electron image, the region having a high RH concentration inside the main phase particles becomes brighter (whiter) than the region having a low RH concentration. From the above, it is possible to determine whether each main phase particle is a core-shell main phase particle 13 or an inverted core-shell main phase particle 11 depending on the position of a bright portion inside the main phase particle.

ここで、逆コアシェル主相粒子１１は、前記Ｒ２Ｔ１４Ｂ結晶からなる主相粒子であって、コア部１１ａにおける全ＲＨ濃度（ａｔ％）をＣＲＣ、シェル部１１ｂにおける全ＲＨ濃度（ａｔ％）をＣＲＳとした場合に、ＣＲＣ／ＣＲＳ＞１．０である主相粒子である。 Here, the reverse core shell main phase particle 11 is a main phase particle composed of the R2 T 14 B crystal, and the total RH concentration (at%) in the core portion 11a is C RC , and the total RH concentration in the shell portion 11b ( When at%) is C RS , it is a main phase particle in which C RC / C RS > 1.0.

すなわち、逆コアシェル主相粒子１１は、一般的に知られているコアシェル主相粒子とは逆に、シェル部１１ｂにおける全ＲＨ濃度よりもコア部１１ａにおける全ＲＨ濃度の方が高い主相粒子である。 That is, the reverse core-shell main phase particles 11 are the main phase particles having a higher total RH concentration in the core portion 11a than the total RH concentration in the shell portion 11b, contrary to the generally known core-shell main phase particles. be.

ＣＲＣおよびＣＲＳの測定箇所には、特に制限はない。例えば、以下の通りとすることができる。 There are no particular restrictions on the measurement points of C RC and C RS . For example, it can be as follows.

まず、濃度を測定する逆コアシェル主相粒子１１を透過型電子顕微鏡（ＴＥＭ）で観察し、長さが最大となる直径を特定する。次に、当該直径と粒界との二つの交点を特定する。そして、当該二つの交点の中点を中心とする２０ｎｍ×２０ｎｍの領域における全ＲＨ濃度を測定し、コア部における全ＲＨ濃度ＣＲＣとすることができる。 First, the inverted core-shell main phase particles 11 for measuring the concentration are observed with a transmission electron microscope (TEM), and the diameter at which the length is maximized is specified. Next, the two intersections of the diameter and the grain boundary are specified. Then, the total RH concentration in the region of 20 nm × 20 nm centered on the midpoint of the two intersections can be measured to obtain the total RH concentration C RC in the core portion.

次に、当該二つの交点のうち一つの交点を選択する。そして、当該交点から前記長さが最大となる直径に沿って２０ｎｍ、逆コアシェル主相粒子側に侵入した点を中心とする２０ｎｍ×２０ｎｍの領域における全ＲＨ濃度を測定し、シェル部における全ＲＨ濃度ＣＲＳとすることができる。 Next, one of the two intersections is selected. Then, the total RH concentration in the region of 20 nm × 20 nm centered on the point invading the reverse core shell main phase particle side at 20 nm along the diameter at which the length becomes maximum from the intersection is measured, and the total RH in the shell portion is measured. It can be a concentration C RS .

一方、コアシェル主相粒子１３とは、前記Ｒ２Ｔ１４Ｂ結晶からなる主相粒子であって、コア部１３ａにおける全ＲＨ濃度（ａｔ％）をＣＮＣ、シェル部１３ｂにおける全ＲＨ濃度（ａｔ％）をＣＮＳとした場合に、ＣＮＣ／ＣＮＳ＜１．０である主相粒子である。 On the other hand, the core-shell main phase particles 13 are main phase particles composed of the R2 T 14 B crystals, and the total RH concentration (at%) in the core portion 13a is C NC , and the total RH concentration (at%) in the shell portion 13b. %) Is C NS , and C NC / C NS <1.0 is the main phase particle.

すなわち、コアシェル主相粒子１３は、一般的に知られているコアシェル主相粒子と同様に、シェル部１３ｂにおける全ＲＨ濃度よりもコア部１３ａにおける全ＲＨ濃度の方が低い主相粒子である。 That is, the core-shell main phase particles 13 are the main phase particles having a lower total RH concentration in the core portion 13a than the total RH concentration in the shell portion 13b, similarly to the generally known core-shell main phase particles.

ＣＮＣおよびＣＮＳの測定箇所には、特に制限はないが、例えばＣＲＣおよびＣＲＳと同様に測定箇所を設定することができる。 The measurement points of C NC and C NS are not particularly limited, but measurement points can be set in the same manner as, for example, C RC and C RS .

また、逆コアシェル主相粒子１１のコア部１１ａにおける全Ｒ濃度に対する全ＲＨ濃度には特に制限はないが、概ね原子比で３０％以上８０％以下程度である。逆コアシェル主相粒子１１のシェル部１１ｂにおける全Ｒ濃度に対する全ＲＨ濃度には特に制限はないが、概ね原子比で１０％以上３０％以下程度である。 Further, the total RH concentration with respect to the total R concentration in the core portion 11a of the reverse core shell main phase particles 11 is not particularly limited, but is generally about 30% or more and 80% or less in atomic ratio. The total RH concentration with respect to the total R concentration in the shell portion 11b of the reverse core shell main phase particles 11 is not particularly limited, but is generally about 10% or more and 30% or less in terms of atomic ratio.

また、コアシェル主相粒子１３のコア部１３ａにおける全Ｒ濃度に対する全ＲＨ濃度には特に制限はないが、概ね原子比で０％以上１０％以下程度である。コアシェル主相粒子１３のシェル部１３ｂにおける全Ｒ濃度に対する全ＲＨ濃度には特に制限はないが、概ね原子比で１０％以上３０％以下程度である。 Further, the total RH concentration with respect to the total R concentration in the core portion 13a of the core-shell main phase particles 13 is not particularly limited, but is generally about 0% or more and 10% or less in terms of atomic ratio. The total RH concentration with respect to the total R concentration in the shell portion 13b of the core-shell main phase particles 13 is not particularly limited, but is generally about 10% or more and 30% or less in terms of atomic ratio.

以上より、通常は、逆コアシェル主相粒子１１のコア部１１ａが最も全Ｒ濃度に対する全ＲＨ濃度が高く、コアシェル主相粒子１３のコア部１３ａが最も全Ｒ濃度に対する全ＲＨ濃度が低くなる。なお、逆コアシェル主相粒子１１のシェル部１１ｂとコアシェル主相粒子１３のシェル部１３ｂとでは、全Ｒ濃度に対する全ＲＨ濃度は大きく変化しない。 From the above, usually, the core portion 11a of the reverse core-shell main phase particle 11 has the highest total RH concentration with respect to the total R concentration, and the core portion 13a of the core-shell main phase particle 13 has the lowest total RH concentration with respect to the total R concentration. The total RH concentration does not change significantly with respect to the total R concentration between the shell portion 11b of the reverse core-shell main phase particles 11 and the shell portion 13b of the core-shell main phase particles 13.

なお、図２では、逆コアシェル主相粒子１１はコア部１１ａの表面全てをシェル部１１ｂが覆っているが、コア部１１ａの表面全てをシェル部１１ｂが覆う必要はなく、コア部１１ａの表面の６０％以上を覆っていればよい。コア部１１ａおよびシェル部１１ｂの区別はＳＥＭにより行うことができる。コアシェル主相粒子１３についても同様である。 In FIG. 2, the reverse core shell main phase particles 11 cover the entire surface of the core portion 11a with the shell portion 11b, but it is not necessary for the shell portion 11b to cover the entire surface of the core portion 11a, and the surface of the core portion 11a. It suffices to cover 60% or more of. The core portion 11a and the shell portion 11b can be distinguished by SEM. The same applies to the core-shell main phase particles 13.

本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石１は、逆コアシェル主相粒子１１を含むことにより、重希土類元素の使用量を低減しても高い磁気特性を有する永久磁石となる。逆コアシェル主相粒子１１を含むことにより上記の効果が得られるメカニズムは、以下に示すメカニズムであると考えられる。 The RTB-based sintered magnet 1 according to the present embodiment is a permanent magnet having high magnetic properties even if the amount of heavy rare earth elements used is reduced by containing the reverse core shell main phase particles 11. The mechanism by which the above effect is obtained by including the inverted core-shell main phase particles 11 is considered to be the mechanism shown below.

逆コアシェル主相粒子１１は、シェル部１１ｂと比較してより多くのＲＨを含むことにより、コア部１１ａにおいて異方性磁界が高くなる。そのため、逆コアシェル主相粒子１１のコア部１１ａとシェル部１１ｂとの界面において、異方性磁界が変化すると考えられる。上記の逆コアシェル主相粒子１１内での異方性磁界の変化により、ピニング力が増加すると考えられる。したがって、逆コアシェル主相粒子１１を含むＲ－Ｔ－Ｂ系焼結磁石１は保磁力が向上すると考えられる。 Since the inverted core shell main phase particles 11 contain more RH as compared with the shell portion 11b, the anisotropic magnetic field becomes higher in the core portion 11a. Therefore, it is considered that the anisotropic magnetic field changes at the interface between the core portion 11a and the shell portion 11b of the reverse core shell main phase particles 11. It is considered that the pinning force increases due to the change in the anisotropic magnetic field in the reverse core shell main phase particles 11. Therefore, it is considered that the RTB-based sintered magnet 1 including the reverse core-shell main phase particles 11 has an improved coercive force.

また、図１Ａおよび図２に示すように、全主相粒子に対する逆コアシェル主相粒子１１の存在比率は、磁石中央部よりも磁石表層部の方が高い。そして、主に逆コアシェル主相粒子１１からなる逆コアシェル粒子層１ａが磁石表層部に存在していることが好ましい。 Further, as shown in FIGS. 1A and 2, the abundance ratio of the reverse core shell main phase particles 11 to all the main phase particles is higher in the magnet surface layer portion than in the magnet central portion. It is preferable that the reverse core shell particle layer 1a mainly composed of the reverse core shell main phase particles 11 is present on the magnet surface layer portion.

逆コアシェル主相粒子１１はコア部１１ａにより多くの重希土類元素ＲＨを含有する。そのため、逆コアシェル主相粒子１１自体は残留磁束密度および飽和磁化が低い。逆コアシェル主相粒子１１は飽和磁化が低いため、ある逆コアシェル主相粒子１１が磁化反転しても、当該逆コアシェル主相粒子１１に隣接する主相粒子の磁化反転に及ぼす影響が小さい。すなわち、主に逆コアシェル主相粒子１１からなる逆コアシェル粒子層１ａがＲ－Ｔ－Ｂ系焼結磁石１の磁石表層部に存在していることにより、磁石表面から発生する逆磁区の伝達が抑制される。したがって、逆コアシェル主相粒子１１が磁石表層部により多く存在し、逆コアシェル粒子層１ａが磁石表層部に存在していることにより、Ｒ－Ｔ－Ｂ系焼結磁石１は保磁力がさらに向上する。 The inverted core-shell main phase particles 11 contain more heavy rare earth element RH in the core portion 11a. Therefore, the reverse core-shell main phase particles 11 themselves have low residual magnetic flux density and saturation magnetization. Since the reverse core-shell main phase particle 11 has a low saturation magnetization, even if a certain reverse core-shell main phase particle 11 is magnetized inversion, the influence on the magnetization reversal of the main phase particle adjacent to the reverse core-shell main phase particle 11 is small. That is, since the reverse core shell particle layer 1a mainly composed of the reverse core shell main phase particles 11 is present on the magnet surface layer portion of the RTB-based sintered magnet 1, the transmission of the reverse magnetic domain generated from the magnet surface is transmitted. It is suppressed. Therefore, the coercive force of the RTB-based sintered magnet 1 is further improved by the presence of the reverse core shell main phase particles 11 in the magnet surface layer portion and the reverse core shell particle layer 1a in the magnet surface layer portion. do.

本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石１に含まれる逆コアシェル主相粒子１１において、ＣＲＣ／ＣＲＳ＞１．５であることが好ましく、ＣＲＣ／ＣＲＳ＞３．０であることがより好ましい。逆コアシェル主相粒子１１において、シェル部１１ｂに対してコア部１１ａに重希土類元素ＲＨがより多く存在するほど上記の効果が大きくなり、保磁力がさらに向上するため好ましい。 In the reverse core shell main phase particles 11 included in the RTB-based sintered magnet 1 according to the present embodiment, C RC / C RS > 1.5 is preferable, and C RC / C RS > 3.0. Is more preferable. In the reverse core-shell main phase particles 11, the more the heavy rare earth element RH is present in the core portion 11a with respect to the shell portion 11b, the greater the above-mentioned effect and the coercive force is further improved, which is preferable.

なお、本実施形態では、磁石表層部とは、磁石表面から磁石内部に向かって５μｍ以上１５０μｍ以下の領域を指す。磁石中央部とは、磁石表層部より内側にある部分を指す。また、逆コアシェル粒子層１ａはＲ－Ｔ－Ｂ系焼結磁石１の全ての磁石表層部に存在している必要はなく、一部の磁石表層部のみに存在していてもよい。また、図２に示すように、逆コアシェル粒子層１ａは逆コアシェル主相粒子１１が存在している層を指す。また、コアシェル粒子層１ｂはコアシェル主相粒子１３が存在し、逆コアシェル主相粒子１１が存在していない層を指す。 In the present embodiment, the magnet surface layer portion refers to a region of 5 μm or more and 150 μm or less from the magnet surface toward the inside of the magnet. The central portion of the magnet refers to a portion inside the surface layer portion of the magnet. Further, the reverse core-shell particle layer 1a does not have to be present in all the magnet surface layer portions of the RTB-based sintered magnet 1, and may be present only in a part of the magnet surface layer portions. Further, as shown in FIG. 2, the reverse core shell particle layer 1a refers to a layer in which the reverse core shell main phase particles 11 are present. Further, the core-shell particle layer 1b refers to a layer in which the core-shell main phase particles 13 are present and the reverse core-shell main phase particles 11 are not present.

逆コアシェル粒子層１ａの厚さには特に制限はない。１０μｍ以上１００μｍ以下とすることが好ましい。 The thickness of the inverted core-shell particle layer 1a is not particularly limited. It is preferably 10 μm or more and 100 μm or less.

また、本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石は、図１Ａに示すように、磁石中央部から磁石表層部に向かってコアシェル粒子層１ｂおよび逆コアシェル粒子層１ａがこの順番で並んでいても良い。また、逆コアシェル粒子層１ａおよびコアシェル粒子層１ｂのみからなっていてもよい。 Further, in the RTB-based sintered magnet according to the present embodiment, as shown in FIG. 1A, the core-shell particle layer 1b and the reverse core-shell particle layer 1a are arranged in this order from the central portion of the magnet toward the surface layer portion of the magnet. You can go out. Further, it may be composed of only the reverse core-shell particle layer 1a and the core-shell particle layer 1b.

＜Ｒ－Ｔ－Ｂ系焼結磁石の製造方法＞
次に、本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石の製造方法を説明する。 <Manufacturing method of RTB-based sintered magnet>
Next, a method for manufacturing the RTB-based sintered magnet according to the present embodiment will be described.

なお、以下では、粉末冶金法で作製され、重希土類元素が粒界拡散されたＲ－Ｔ－Ｂ系焼結磁石を例に説明するが、本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石の製造方法は、特に限定されるものではなく、他の方法も用いることができる。 In the following, an RTB-based sintered magnet manufactured by a powder metallurgy method and having a heavy rare earth element diffused at the grain boundary will be described as an example, but the RTB-based sintered magnet according to the present embodiment will be described. The method for manufacturing the magnet is not particularly limited, and other methods can also be used.

本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石の製造方法には、原料粉末を成形して成形体を得る成形工程と、前記成形体を焼結して焼結体を得る焼結工程と、前記焼結体を焼結温度よりも低い温度で一定時間保持する時効工程とを有する。 The method for manufacturing an RTB-based sintered magnet according to the present embodiment includes a molding step of molding a raw material powder to obtain a molded body and a sintering step of sintering the molded body to obtain a sintered body. And an aging step of holding the sintered body at a temperature lower than the sintering temperature for a certain period of time.

以下、Ｒ－Ｔ－Ｂ系焼結磁石の製造方法について詳しく説明していくが、特記しない事項については、公知の方法を用いればよい。 Hereinafter, the method for manufacturing the RTB-based sintered magnet will be described in detail, but for matters not otherwise specified, a known method may be used.

［原料粉末の準備工程］
原料粉末は、公知の方法により作製することができる。本実施形態では、主にＲ２Ｔ１４Ｂ相からなる一種類の原料合金を用いる一合金法でＲ－Ｔ－Ｂ系焼結磁石を製造するが、二種類の原料合金を用いる二合金法により製造してもよい。ここで、原料合金の組成は、最終的に得るＲ－Ｔ－Ｂ系焼結磁石の組成となるように制御する。 [Preparation process of raw material powder]
The raw material powder can be produced by a known method. In the present embodiment, the RTB-based sintered magnet is manufactured by a one-alloy method using one kind of raw material alloy mainly composed of R 2 T 14 B phase, but a two-alloy method using two kinds of raw material alloys. May be manufactured by Here, the composition of the raw material alloy is controlled so as to be the composition of the RTB-based sintered magnet finally obtained.

まず、本実施形態に係る原料合金の組成に対応する原料金属を準備し、当該原料金属から本実施形態に対応する原料合金を作製する。原料合金の作製方法に特に制限はない。例えば、ストリップキャスト法にて原料合金を作製することができる。 First, a raw material metal corresponding to the composition of the raw material alloy according to the present embodiment is prepared, and a raw material alloy corresponding to the present embodiment is produced from the raw material metal. There are no particular restrictions on the method for producing the raw material alloy. For example, a raw material alloy can be produced by a strip casting method.

原料合金を作製した後に、作製した原料合金を粉砕する（粉砕工程）。粉砕工程は、２段階で実施してもよく、１段階で実施してもよい。粉砕の方法には特に限定はない。例えば、各種粉砕機を用いる方法で実施される。例えば、粉砕工程を粗粉砕工程および微粉砕工程の２段階で実施し、粗粉砕工程は例えば水素粉砕処理を行うことが可能である。具体的には、原料合金に対して室温で水素を吸蔵させた後に、Ａｒガス雰囲気下で４００℃以上６５０℃以下、０．５時間以上２時間以下で脱水素を行うことが可能である。また、微粉砕工程は、粗粉砕後の粉末に対して、例えばオレイン酸アミド、ステアリン酸亜鉛などを添加したのちに、例えばジェットミル、湿式アトライター等を用いて行うことができる。得られる微粉砕粉末（原料粉末）の粒径には特に制限はない。例えば、粒径（Ｄ５０）が１μｍ以上１０μｍ以下の微粉砕粉末（原料粉末）となるように微粉砕を行うことができる。 After producing the raw material alloy, the produced raw material alloy is crushed (crushing step). The crushing step may be carried out in two steps or in one step. The crushing method is not particularly limited. For example, it is carried out by a method using various crushers. For example, the pulverization step can be carried out in two stages, a coarse pulverization step and a fine pulverization step, and the coarse pulverization step can be, for example, a hydrogen pulverization treatment. Specifically, it is possible to occlude hydrogen in the raw material alloy at room temperature and then dehydrogenate in an Ar gas atmosphere at 400 ° C. or higher and 650 ° C. or lower, and 0.5 hours or longer and 2 hours or lower. Further, the fine pulverization step can be performed by adding, for example, oleic acid amide, zinc stearate, or the like to the powder after coarse pulverization, and then using, for example, a jet mill, a wet attritor, or the like. The particle size of the obtained finely pulverized powder (raw material powder) is not particularly limited. For example, fine pulverization can be performed so that the finely pulverized powder (raw material powder) having a particle size (D50) of 1 μm or more and 10 μm or less is obtained.

［成形工程］
成形工程では、粉砕工程により得られた微粉砕粉末（原料粉末）を所定の形状に成形する。成形方法には特に限定はないが、本実施形態では、微粉砕粉末（原料粉末）を金型内に充填し、磁場中で加圧する。 [Molding process]
In the molding step, the finely crushed powder (raw material powder) obtained in the crushing step is molded into a predetermined shape. The molding method is not particularly limited, but in the present embodiment, the finely pulverized powder (raw material powder) is filled in the mold and pressurized in a magnetic field.

成形時の加圧は、３０ＭＰａ以上３００ＭＰａ以下で行うことが好ましい。印加する磁場は、９５０ｋＡ／ｍ以上１６００ｋＡ／ｍ以下であることが好ましい。微粉砕粉末（原料粉末）を成形して得られる成形体の形状は特に限定されるものではなく、例えば直方体、平板状、柱状等、所望とするＲ－Ｔ－Ｂ系焼結磁石の形状に応じて任意の形状とすることができる。 The pressurization during molding is preferably performed at 30 MPa or more and 300 MPa or less. The applied magnetic field is preferably 950 kA / m or more and 1600 kA / m or less. The shape of the molded body obtained by molding the finely pulverized powder (raw material powder) is not particularly limited, and the desired shape of the RTB-based sintered magnet such as a rectangular parallelepiped, a flat plate, or a columnar shape can be obtained. It can have any shape depending on the shape.

［焼結工程］
焼結工程は、成形体を真空または不活性ガス雰囲気中で焼結し、焼結体を得る工程である。焼結温度は、組成、粉砕方法、粒度と粒度分布の違い等、諸条件により調整する必要があるが、成形体に対して、例えば、真空中または不活性ガスの存在下、１０００℃以上１２００℃以下、１時間以上１０時間以下で加熱する処理を行うことにより焼結する。これにより、高密度の焼結体（焼結磁石）が得られる。 [Sintering process]
The sintering step is a step of sintering a molded body in a vacuum or an atmosphere of an inert gas to obtain a sintered body. The sintering temperature needs to be adjusted according to various conditions such as composition, pulverization method, difference in particle size and particle size distribution, etc. Sintering is performed by heating at a temperature of 1 ° C. or higher and 1 hour or longer and 10 hours or lower. As a result, a high-density sintered body (sintered magnet) can be obtained.

［時効処理工程］
時効処理工程は、焼結工程後の焼結体（焼結磁石）に対して、焼結温度よりも低い温度で加熱することにより行う。時効処理の温度および時間には特に制限はないが、例えば４５０℃以上９００℃以下で０．２時間以上３時間以下、行うことができる。なお、この時効処理工程は省略してもよい。 [Aging process]
The aging treatment step is performed by heating the sintered body (sintered magnet) after the sintering step at a temperature lower than the sintering temperature. The temperature and time of the aging treatment are not particularly limited, but can be carried out, for example, at 450 ° C. or higher and 900 ° C. or lower for 0.2 hours or longer and 3 hours or shorter. The aging treatment step may be omitted.

また、時効処理工程は１段階で行ってもよく、２段階で行ってもよい。２段階で行う場合には、例えば１段階目を７００℃以上９００℃以下で０．２時間以上３時間以下とし、２段階目を４５０℃以上７００℃以下で０．２時間以上３時間以下としてもよい。また、１段階目と２段階目とを連続して行ってもよく、１段階目の後に一度室温近傍まで冷却してから再加熱して２段階目を行ってもよい。 Further, the aging treatment step may be performed in one step or in two steps. In the case of performing in two steps, for example, the first step is set to 700 ° C. or higher and 900 ° C. or lower for 0.2 hours or more and 3 hours or less, and the second step is set to 450 ° C. or higher and 700 ° C. or lower for 0.2 hours or more and 3 hours or less. May be good. Further, the first step and the second step may be continuously performed, or after the first step, the first step may be cooled to near room temperature and then reheated to perform the second step.

［逆コアシェル主相粒子生成工程］
本実施形態における逆コアシェル主相粒子の生成方法には特に制限がない。例えば、以下に示す分解工程、粒界拡散工程および再結晶化工程を経ることで逆コアシェル主相粒子を得ることができる。 [Reverse core shell main phase particle generation process]
There is no particular limitation on the method for producing the inverted core shell main phase particles in the present embodiment. For example, the reverse core shell main phase particles can be obtained through the following decomposition steps, grain boundary diffusion steps, and recrystallization steps.

［分解工程］
分解工程とは、主に磁石表層部に存在するＲ２Ｔ１４Ｂ結晶からなる主相粒子を分解不均化する工程である。分解工程の条件は、主に磁石表層部に存在するＲ２Ｔ１４Ｂ結晶からなる主相粒子を分解させることができれば特に制限はない。 [Disassembly process]
The decomposition step is a step of decomposing and disproportionating the main phase particles composed of R 2 T 14 B crystals mainly present on the surface layer of the magnet. The conditions of the decomposition step are not particularly limited as long as the main phase particles composed of R 2 T 14 B crystals mainly present on the surface layer of the magnet can be decomposed.

例えばＨ２ガス、ＣＯガスまたはＮ２ガスを含む不活性雰囲気中、６００℃以上９００℃以下程度で５分間以上６０分間以下程度、加熱することで、主に磁石表層部に存在する主相粒子にＨ２、ＣＯまたはＮ２を吸蔵させて分解させ、不均化させることになる。 For example, by heating in an inert atmosphere containing H 2 gas, CO gas or N 2 gas at 600 ° C. or higher and 900 ° C. or lower for 5 minutes or longer and 60 minutes or lower, the main phase particles mainly present on the surface layer of the magnet. H 2 , CO or N 2 is occluded and decomposed to disproportionate.

Ｈ２ガス、ＣＯガスまたはＮ２ガスの濃度、加熱温度および／または加熱時間を制御することで、主相粒子が不均化する領域の厚さを制御し、最終的に得られる逆コアシェル粒子層の厚さを制御することができる。 By controlling the concentration of H 2 gas, CO gas or N 2 gas, heating temperature and / or heating time, the thickness of the region where the main phase particles disproportionate is controlled, and the finally obtained inverted core shell particles. The thickness of the layer can be controlled.

また、酸化性ガスを含む酸化性雰囲気中、３００℃以上５００℃以下程度で２０分間以上６０分間以下程度、加熱することでも、磁石表層部に存在する主相粒子を分解不均化させることができる。 Further, the main phase particles existing on the surface layer of the magnet can be decomposed and disproportionated by heating at 300 ° C. or higher and 500 ° C. or lower for 20 minutes or longer and 60 minutes or lower in an oxidizing atmosphere containing an oxidizing gas. can.

［拡散処理工程］
本実施形態では、分解工程に続いて、さらに重希土類元素を拡散させる拡散処理工程を有する。拡散処理は、重希土類元素を含む化合物等を、前記分解工程を行った焼結体の表面に付着させた後、熱処理を行うことにより、実施することができる。重希土類元素を含む化合物を付着させる方法には特に制限はなく、たとえば重希土類元素を含むスラリーを塗布することで付着させることができる。この場合には、スラリーの塗布量とスラリーに含まれる重希土類元素の濃度を制御することで、上記のＣＲＣ／ＣＲＳを制御することができる。 [Diffusion processing process]
In the present embodiment, following the decomposition step, there is a diffusion treatment step of further diffusing heavy rare earth elements. The diffusion treatment can be carried out by adhering a compound or the like containing a heavy rare earth element to the surface of the sintered body subjected to the decomposition step, and then performing a heat treatment. The method for adhering the compound containing the heavy rare earth element is not particularly limited, and for example, the compound can be attached by applying a slurry containing the heavy rare earth element. In this case, the above C RC / C RS can be controlled by controlling the coating amount of the slurry and the concentration of the heavy rare earth element contained in the slurry.

ただし、前記重希土類元素を付着させる方法は特に制限は無い。例えば、蒸着、スパッタリング、電着、スプレー塗布、刷毛塗り、ジェットディスペンサ、ノズル、スクリーン印刷、スキージ印刷、シート工法等を用いる方法がある。 However, the method of adhering the heavy rare earth element is not particularly limited. For example, there are methods using vapor deposition, sputtering, electrodeposition, spray coating, brush coating, jet dispenser, nozzle, screen printing, squeegee printing, sheet construction method and the like.

重希土類化合物は粒子状であることが好ましい。また、平均粒径は１００ｎｍ以上５０μｍ以下であることが好ましく、１μｍ以上１０μｍ以下であることがより好ましい。 The heavy rare earth compound is preferably in the form of particles. The average particle size is preferably 100 nm or more and 50 μm or less, and more preferably 1 μm or more and 10 μm or less.

スラリーに用いる溶媒としては、重希土類化合物を溶解させずに均一に分散させ得るものが好ましい。例えば、アルコール、アルデヒド、ケトン等が挙げられ、なかでもエタノールが好ましい。 As the solvent used for the slurry, a solvent capable of uniformly dispersing the heavy rare earth compound without dissolving it is preferable. For example, alcohols, aldehydes, ketones and the like can be mentioned, with ethanol being preferred.

スラリー中の重希土類化合物の含有量には特に制限はない。例えば、５０重量％以上９０重量％以下であってもよい。スラリーには、必要に応じて重希土類化合物以外の成分をさらに含有させてもよい。例えば、重希土類化合物粒子の凝集を防ぐための分散剤等が挙げられる。 The content of the heavy rare earth compound in the slurry is not particularly limited. For example, it may be 50% by weight or more and 90% by weight or less. If necessary, the slurry may further contain components other than the heavy rare earth compound. For example, a dispersant for preventing agglomeration of heavy rare earth compound particles can be mentioned.

上記の拡散処理工程を、前記分解工程を行った焼結体に対して行うことにより、焼結体全体の粒界に加えて、磁石表層部に存在する主相粒子が分解不均化された領域においては融点の低下に伴い液相が生成し、重希土類元素ＲＨが液相中に拡散することになる。そして、Ｒとして重希土類元素ＲＨを含むＲ２Ｔ１４Ｂ結晶はＲとして重希土類元素ＲＨを含まないＲ２Ｔ１４Ｂ結晶よりも生成しやすいため、拡散した重希土類元素を含む液相が部分的にＲ２Ｔ１４Ｂ結晶化し、主に最終的に得られる逆コアシェル主相粒子のコア部となる。 By performing the above diffusion treatment step on the sintered body subjected to the decomposition step, in addition to the grain boundaries of the entire sintered body, the main phase particles existing on the surface layer of the magnet were decomposed and disproportionated. In the region, a liquid phase is generated as the melting point decreases, and the heavy rare earth element RH diffuses into the liquid phase. Since the R 2 T 14 B crystal containing the heavy rare earth element RH as R is easier to form than the R 2 T 14 B crystal containing no heavy rare earth element RH as R, the liquid phase containing the diffused heavy rare earth element is partially formed. R 2 T 14 B crystallizes and becomes the core part of the main phase particles of the inverted core shell that is finally obtained.

拡散処理工程の条件には特に制限はないが、６５０℃以上１０００℃以下で１時間以上２４時間以下、行うことが好ましい。上記の範囲内の温度および時間とすることで、液相に取り込まれる重希土類元素ＲＨの割合を多くしやすくなる。また、拡散処理工程の際に、上記のＨ２ガス、ＣＯガス、Ｎ２ガスまたは酸化性ガスに含まれる各成分が放出される。 The conditions of the diffusion treatment step are not particularly limited, but it is preferably performed at 650 ° C. or higher and 1000 ° C. or lower for 1 hour or longer and 24 hours or shorter. By setting the temperature and time within the above range, it becomes easy to increase the ratio of the heavy rare earth element RH incorporated into the liquid phase. Further, during the diffusion treatment step, each component contained in the above-mentioned H 2 gas, CO gas, N 2 gas or oxidizing gas is released.

［再結晶化工程］
拡散処理工程後に再結晶化工程を経ることにより、重希土類元素ＲＨが取り込まれた液相のうち、粒界拡散工程で結晶化しなかった液相も結晶化され、Ｒ２Ｔ１４Ｂ結晶となる。再結晶化工程は、例えば、５０℃／分以上５００℃／分以下の速度で急冷を行うことにより行われる。再結晶化工程により、拡散処理工程の際に結晶化された重希土類元素ＲＨの含有量が多いＲ２Ｔ１４Ｂ結晶の周囲に存在する液相も結晶化する。さらに、再結晶化工程においては、重希土類元素ＲＨの含有量が多いＲ２Ｔ１４Ｂ結晶から発生し始め、重希土類元素ＲＨの含有量が少ないＲ２Ｔ１４Ｂ結晶が重希土類元素ＲＨの含有量が多いＲ２Ｔ１４Ｂ結晶の周囲に形成される傾向にある。その結果、逆コアシェル主相粒子が形成される。冷却速度には特に制限はないが、冷却速度が速すぎると非晶質および副相を多く含んだ微結晶になる傾向にあり、冷却速度が遅すぎると逆コアシェル主相粒子１１のコア部１１ａとシェル部１１ｂとの界面が不明瞭になる傾向にある。 [Recrystallization step]
By going through the recrystallization step after the diffusion treatment step, among the liquid phases in which the heavy rare earth element RH is incorporated, the liquid phase that was not crystallized in the grain boundary diffusion step is also crystallized to become R 2 T 14 B crystals. .. The recrystallization step is performed, for example, by quenching at a rate of 50 ° C./min or more and 500 ° C./min or less. By the recrystallization step, the liquid phase existing around the R 2 T 14 B crystal having a high content of the heavy rare earth element RH crystallized in the diffusion treatment step is also crystallized. Further, in the recrystallization step, the R 2 T 14 B crystal having a high content of the heavy rare earth element RH starts to be generated, and the R 2 T 14 B crystal having a low content of the heavy rare earth element RH is the heavy rare earth element RH. It tends to be formed around R 2 T 14 B crystals with high content. As a result, inverted core-shell main phase particles are formed. The cooling rate is not particularly limited, but if the cooling rate is too fast, it tends to be amorphous and microcrystals containing a large amount of secondary phases, and if the cooling rate is too slow, the core portion 11a of the reverse core shell main phase particles 11 tends to be formed. The interface between the shell portion 11b and the shell portion 11b tends to be unclear.

以上より、本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石の製造方法としては、少なくとも、磁石表層部の主相粒子を分解不均化する分解工程、液相を生成し前記液相に重希土類元素を拡散させる粒界拡散工程、および部分的に結晶化したＲ２Ｔ１４Ｂ結晶の周囲の液相を結晶化させる再結晶化工程がこの順で行われることが重要である。これにより、Ｒ－Ｔ－Ｂ系焼結磁石の磁石表層部に逆コアシェル主相粒子を発生させ、逆コアシェル粒子層を形成することができる。上記の分解工程、粒界拡散工程、および再結晶化工程の方法および条件はあくまでも例示である。分解工程は磁石表層部の主相粒子を分解不均化する工程であればよい。粒界拡散工程は液相を生成し、前記液相に重希土類元素を拡散させることができればよい。再結晶化工程は再結晶により逆コアシェル主相粒子を発生させ、逆コアシェル粒子層を形成させることができればよい。 Based on the above, as a method for manufacturing an RTB-based sintered magnet according to the present embodiment, at least a decomposition step of decomposing and disproportionating the main phase particles on the surface layer of the magnet and a liquid phase are generated and the liquid phase is formed. It is important that the grain boundary diffusion step of diffusing the heavy rare earth elements and the recrystallization step of crystallizing the liquid phase around the partially crystallized R 2 T 14 B crystal are performed in this order. As a result, the reverse core-shell main phase particles can be generated on the magnet surface layer portion of the RTB-based sintered magnet to form the reverse core-shell particle layer. The methods and conditions of the decomposition step, the grain boundary diffusion step, and the recrystallization step are merely examples. The decomposition step may be any step as long as it is a step of decomposing and disproportionating the main phase particles on the surface layer of the magnet. The grain boundary diffusion step only needs to be able to generate a liquid phase and diffuse heavy rare earth elements into the liquid phase. In the recrystallization step, it is sufficient that the reverse core shell main phase particles can be generated by recrystallization to form the reverse core shell particle layer.

なお、分解工程にて分解不均化しなかった主相粒子については、粒界拡散工程において粒界拡散された重希土類元素ＲＨによりシェル部が形成され、通常のコアシェル主相粒子となり、コアシェル粒子層を形成する。 For the main phase particles that were not decomposed and disproportionated in the decomposition step, a shell portion was formed by the heavy rare earth element RH diffused at the grain boundary diffusion step to become normal core shell main phase particles, and the core shell particle layer. To form.

［再時効処理工程］
再時効処理工程は、再結晶化工程後の焼結磁石に対して、拡散処理工程の最高温度よりも低い温度で加熱することにより行う。再時効処理の温度および時間には特に制限はないが、例えば４５０℃以上８００℃以下で０．２時間以上３時間以下、行うことができる。 [Re-aging process]
The reaging treatment step is performed by heating the sintered magnet after the recrystallization step at a temperature lower than the maximum temperature of the diffusion treatment step. The temperature and time of the re-aging treatment are not particularly limited, but can be carried out, for example, at 450 ° C. or higher and 800 ° C. or lower for 0.2 hours or longer and 3 hours or shorter.

以上の工程により得られたＲ－Ｔ－Ｂ系焼結磁石は、めっきや樹脂被膜や酸化処理、化成処理などの表面処理を施してもよい。これにより、耐食性をさらに向上させることができる。 The RTB-based sintered magnet obtained by the above steps may be subjected to surface treatment such as plating, resin coating, oxidation treatment, or chemical conversion treatment. Thereby, the corrosion resistance can be further improved.

さらに、本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石を切断、分割して得られる磁石を用いることができる。 Further, a magnet obtained by cutting and dividing the RTB-based sintered magnet according to the present embodiment can be used.

具体的には、本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石は、モータ、コンプレッサー、磁気センサー、スピーカ等の用途に好適に用いられる。 Specifically, the RTB-based sintered magnet according to the present embodiment is suitably used for applications such as motors, compressors, magnetic sensors, and speakers.

また、本実施形態に係るＲ－Ｔ－Ｂ系焼結磁石は、単独で用いてもよく、２個以上のＲ－Ｔ－Ｂ系焼結磁石を必要に応じて結合させて用いてもよい。結合方法に特に制限はない。例えば、機械的に結合させる方法や樹脂モールドで結合させる方法がある。 Further, the RTB-based sintered magnet according to the present embodiment may be used alone, or two or more RT-B-based sintered magnets may be combined and used as necessary. .. There are no particular restrictions on the joining method. For example, there are a method of mechanically bonding and a method of bonding with a resin mold.

２個以上のＲ－Ｔ－Ｂ系焼結磁石を結合させることで、大きなＲ－Ｔ－Ｂ系焼結磁石を容易に製造することができる。２個以上のＲ－Ｔ－Ｂ系焼結磁石を結合させた磁石は、特に大きなＲ－Ｔ－Ｂ系焼結磁石が求められる用途、例えば、ＩＰＭモータ、風力発電機、大型モータ等に好ましく用いられる。 By coupling two or more RTB-based sintered magnets, a large RTB-based sintered magnet can be easily manufactured. A magnet in which two or more RTB-based sintered magnets are coupled is preferable for applications in which a particularly large RTB-based sintered magnet is required, for example, an IPM motor, a wind power generator, a large motor, or the like. Used.

なお、本発明は、上述した実施形態のように、磁石中央部から磁石表層部に向かって、コアシェル粒子層１ｂ、逆コアシェル粒子層１ａの順番に並んでいる態様に限定されず、本発明の範囲内で種々に改変することができる。 The present invention is not limited to the embodiment in which the core-shell particle layer 1b and the reverse core-shell particle layer 1a are arranged in this order from the central portion of the magnet toward the surface layer portion of the magnet as in the above-described embodiment. It can be modified in various ways within the range.

例えば、図１Ｂに示すように、磁石中央部において、コアシェル粒子層１ｂに加えて、コアシェル構造を有さない非コアシェル主相粒子のみからなる非コアシェル粒子層１ｃが存在するＲ－Ｔ－Ｂ系焼結磁石１０の実施形態が考えられる。そして、磁石中央部から磁石表層部に向かって、非コアシェル粒子層１ｃ、コアシェル粒子層１ｂ、逆コアシェル粒子層１ａの順番に並んでいてもよい。また、逆コアシェル粒子層１ａ、コアシェル粒子層１ｂおよび非コアシェル粒子層１ｃのみからなっていてもよい。なお、主相粒子が「コアシェル構造を有さない」ことは、ＳＥＭを用いて倍率１０００倍以上１００００倍以下で観察した場合に、コアシェル構造が観察されないことにより確認できる。 For example, as shown in FIG. 1B, in the central portion of the magnet, in addition to the core-shell particle layer 1b, an RTB system in which a non-core-shell particle layer 1c composed of only non-core-shell main phase particles having no core-shell structure is present. An embodiment of the sintered magnet 10 is conceivable. Then, the non-core shell particle layer 1c, the core shell particle layer 1b, and the reverse core shell particle layer 1a may be arranged in this order from the central portion of the magnet toward the surface layer portion of the magnet. Further, it may be composed of only the reverse core-shell particle layer 1a, the core-shell particle layer 1b, and the non-core-shell particle layer 1c. It should be noted that the fact that the main phase particles "do not have a core-shell structure" can be confirmed by the fact that the core-shell structure is not observed when observed at a magnification of 1000 times or more and 10000 times or less using SEM.

非コアシェル粒子層１ｃが存在する場合（図１Ｂ）には、非コアシェル粒子層１ｃが存在しない場合（図１Ａ）と比べて残留磁束密度Ｂｒが高くなる傾向にある。 When the non-core-shell particle layer 1c is present (FIG. 1B), the residual magnetic flux density Br tends to be higher than when the non-core-shell particle layer 1c is not present (FIG. 1A).

非コアシェル粒子層１ｃを存在させる方法にも特に制限はない。例えば粒界拡散工程において重希土類元素の付着量を調整する方法、粒界拡散工程において拡散処理時間を短くする方法などがある。 There is no particular limitation on the method for allowing the non-core shell particle layer 1c to exist. For example, there are a method of adjusting the adhesion amount of heavy rare earth elements in the grain boundary diffusion step, a method of shortening the diffusion treatment time in the grain boundary diffusion step, and the like.

次に、本発明を具体的な実施例に基づきさらに詳細に説明するが、本発明は、以下の実施例に限定されない。 Next, the present invention will be described in more detail based on specific examples, but the present invention is not limited to the following examples.

（焼結磁石作製工程）
原料金属として、Ｎｄ、電解鉄、低炭素フェロボロン合金を準備した。さらに、Ａｌ、Ｃｕ、Ｃｏ、Ｚｒを、純金属またはＦｅとの合金の形で準備した。 (Sintered magnet manufacturing process)
As a raw material metal, Nd, electrolytic iron, and a low carbon ferroboron alloy were prepared. Further, Al, Cu, Co and Zr were prepared in the form of a pure metal or an alloy with Fe.

前記原料金属に対し、ストリップキャスト法により、焼結磁石の組成が後述する表１の合金Ａに示す組成となるように焼結体用合金（原料合金）を作製した。表１に示した各元素の含有量（重量％）はＮｄ、Ｂ、Ａｌ、Ｃｕ、Ｃｏ、ＺｒおよびＦｅの合計含有量を１００重量％としたときの値である。また、前記原料合金の合金厚みは０．２ｍｍ以上０．６ｍｍ以下とした。 An alloy for a sintered body (raw material alloy) was prepared from the raw material metal by a strip casting method so that the composition of the sintered magnet had the composition shown in the alloy A in Table 1 described later. The content (% by weight) of each element shown in Table 1 is a value when the total content of Nd, B, Al, Cu, Co, Zr and Fe is 100% by weight. The alloy thickness of the raw material alloy was set to 0.2 mm or more and 0.6 mm or less.

次いで、前記原料合金に対して室温で１時間、水素ガスをフローさせて水素を吸蔵させた。次いで雰囲気をＡｒガスに切り替え、４５０℃で１時間、脱水素処理を行い、原料合金を水素粉砕した。さらに、冷却後にふるいを用いて４００μｍ以下の粒度の粉末とした。 Next, hydrogen gas was allowed to flow through the raw material alloy at room temperature for 1 hour to occlude hydrogen. Next, the atmosphere was switched to Ar gas, dehydrogenation treatment was performed at 450 ° C. for 1 hour, and the raw material alloy was pulverized with hydrogen. Further, after cooling, a sieve was used to prepare a powder having a particle size of 400 μm or less.

次いで、水素粉砕後の原料合金の粉末に対し、重量比で０．１％のオレイン酸アミドを粉砕助剤として添加し、混合した。 Next, 0.1% oleic acid amide by weight was added as a pulverizing aid to the powder of the raw material alloy after hydrogen pulverization, and the mixture was mixed.

次いで、衝突板式のジェットミル装置を用いて窒素気流中で微粉砕し、それぞれ平均粒径が４μｍ程度の微粉（原料粉末）とした。なお、前記平均粒径は、レーザ回折式の粒度分布計で測定した平均粒径Ｄ５０である。 Then, it was finely pulverized in a nitrogen stream using a collision plate type jet mill device to obtain fine powder (raw material powder) having an average particle size of about 4 μm. The average particle size is the average particle size D50 measured by a laser diffraction type particle size distribution meter.

なお、表１に記載していない元素では、Ｈ、Ｓｉ、Ｃａ、Ｌａ、Ｃｅ、Ｃｒ等が検出される場合がある。Ｓｉは主にフェロボロン原料および合金溶解時のるつぼから混入する。Ｃａ、Ｌａ、Ｃｅは希土類の原料から混入する。また、Ｃｒは電解鉄から混入する可能性がある。 For elements not listed in Table 1, H, Si, Ca, La, Ce, Cr and the like may be detected. Si is mainly mixed from the ferroboron raw material and the crucible at the time of melting the alloy. Ca, La and Ce are mixed from rare earth raw materials. In addition, Cr may be mixed from electrolytic iron.

得られた微粉を磁界中で成形して成形体を作製した。このときの印加磁場は１２００ｋＡ／ｍの静磁界である。また、成形時の加圧力は１２０ＭＰａとした。なお、磁界印加方向と加圧方向とを直交させるようにした。この時点での成形体の密度を測定したところ、全ての成形体の密度が４．１０Ｍｇ／ｍ３以上４．２５Ｍｇ／ｍ３以下の範囲内であった。 The obtained fine powder was molded in a magnetic field to prepare a molded product. The applied magnetic field at this time is a static magnetic field of 1200 kA / m. The pressing force during molding was 120 MPa. The magnetic field application direction and the pressurization direction were made orthogonal to each other. When the density of the molded product was measured at this time, the density of all the molded products was in the range of 4.10 Mg / m 3 or more and 4.25 Mg / m 3 or less.

次に、前記成形体を焼結し、焼結磁石を得た。焼結条件は、１０６０℃で４時間保持とした。焼結雰囲気は真空中とした。このとき焼結密度は７．５０Ｍｇ／ｍ３以上７．５５Ｍｇ／ｍ３以下の範囲にあった。その後、Ａｒ雰囲気、大気圧中で、第一時効温度Ｔ１＝９００℃で１時間の第一時効処理を行い、さらに、第二時効温度Ｔ２＝５００℃で１時間の第二時効処理を行った。 Next, the molded body was sintered to obtain a sintered magnet. The sintering conditions were 1060 ° C. for 4 hours. The sintering atmosphere was in vacuum. At this time, the sintering density was in the range of 7.50 Mg / m 3 or more and 7.55 Mg / m 3 or less. Then, in an Ar atmosphere and atmospheric pressure, a first temporary aging treatment was performed at a first temporary aging temperature T1 = 900 ° C. for 1 hour, and a second aging treatment was further performed at a second aging temperature T2 = 500 ° C. for 1 hour. ..

得られた焼結磁石の組成は蛍光Ｘ線分析で評価した。Ｂの含有量はＩＣＰで評価した。各試料における焼結磁石の組成が表２の通りであることを確認した。そして、得られた焼結磁石に対し、以下に示す各実施例１～２２および比較例１～６の処理を行った。 The composition of the obtained sintered magnet was evaluated by fluorescent X-ray analysis. The content of B was evaluated by ICP. It was confirmed that the composition of the sintered magnet in each sample is as shown in Table 2. Then, the obtained sintered magnets were subjected to the treatments of Examples 1 to 22 and Comparative Examples 1 to 6 shown below.

（実施例１）
上記の工程により得られた焼結磁石を、幅２０ｍｍ、長さ２０ｍｍ、配向方向の厚み５ｍｍの直方体となるように加工した後、水素が５体積％、Ａｒが９５体積％である雰囲気ガス中、７５０℃で１０分間保持し、主に磁石表層部に存在する主相粒子を分解不均化した。 (Example 1)
The sintered magnet obtained by the above step is processed into a rectangular parallelepiped having a width of 20 mm, a length of 20 mm, and a thickness of 5 mm in the orientation direction, and then in an atmospheric gas containing 5% by volume of hydrogen and 95% by volume of Ar. , The main phase particles present mainly on the surface layer of the magnet were decomposed and disproportionated by holding at 750 ° C. for 10 minutes.

次いで、焼結磁石の全面に対し、ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）をエタノールに分散させたスラリーを、焼結磁石の重量に対するＴｂの重量が０．５重量％となるように塗布することでＴｂを付着させた。前記スラリーを塗布後に大気圧でＡｒをフローしながら７７０℃で５時間の熱処理を実施し、続いて９５０℃で５時間の熱処理を施し、Ｔｂを粒界拡散させた。 Next, a slurry in which two TbH particles (average particle size D50 = 5 μm) are dispersed in ethanol is applied to the entire surface of the sintered magnet so that the weight of Tb is 0.5% by weight based on the weight of the sintered magnet. By doing so, Tb was attached. After the slurry was applied, heat treatment was performed at 770 ° C. for 5 hours while flowing Ar at atmospheric pressure, and then heat treatment was performed at 950 ° C. for 5 hours to diffuse Tb at grain boundaries.

前記熱処理後に冷却速度２００℃／分で急冷し、液相からＲ２Ｔ１４Ｂ結晶を再結晶化させた。 After the heat treatment, the mixture was rapidly cooled at a cooling rate of 200 ° C./min to recrystallize R 2T 14B crystals from the liquid phase.

その後、Ａｒ雰囲気、大気圧中で、５００℃で１時間の再時効処理を行った。 Then, it was re-aged at 500 ° C. for 1 hour in an Ar atmosphere and atmospheric pressure.

前記再時効処理後の焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った。 The magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the sintered magnet after the re-aging treatment were evaluated with a BH tracer.

（実施例２）
上記の工程により得られた焼結磁石をＣＯが８体積％、Ａｒが９２体積％である雰囲気ガス中、７００℃で１０分間保持し、主に磁石表層部に存在する主相粒子を分解不均化した。 (Example 2)
The sintered magnet obtained by the above step is held at 700 ° C. for 10 minutes in an atmospheric gas containing 8% by volume of CO and 92% by volume of Ar, and the main phase particles mainly present on the surface layer of the magnet are not decomposed. Smoothed out.

次いで、焼結磁石の全面に対し、ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）をエタノールに分散させたスラリーを、焼結磁石の重量に対するＴｂの重量比が０．５重量％となるように塗布することでＴｂを付着させた。前記スラリーを塗布後に大気圧でＡｒをフローしながら７７０℃で５時間の熱処理を実施し、続いて９５０℃で５時間の熱処理を施しＴｂを粒界拡散させた。 Next, a slurry in which two TbH particles (average particle size D50 = 5 μm) were dispersed in ethanol was added to the entire surface of the sintered magnet so that the weight ratio of Tb to the weight of the sintered magnet was 0.5% by weight. Tb was attached by applying. After the slurry was applied, heat treatment was performed at 770 ° C. for 5 hours while flowing Ar at atmospheric pressure, and then heat treatment was performed at 950 ° C. for 5 hours to diffuse Tb at grain boundaries.

前記熱処理後に冷却速度２００℃／分で急冷し、液相からＲ２Ｔ１４Ｂ結晶を再結晶化させた。 After the heat treatment, the mixture was rapidly cooled at a cooling rate of 200 ° C./min to recrystallize R 2T 14B crystals from the liquid phase.

その後、Ａｒ雰囲気、大気圧中で、５００℃で１時間の再時効処理を行った。 Then, it was re-aged at 500 ° C. for 1 hour in an Ar atmosphere and atmospheric pressure.

前記再時効処理後の焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った。 The magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the sintered magnet after the re-aging treatment were evaluated with a BH tracer.

（実施例３）
上記の工程により得られた焼結磁石をＮ２が８体積％、Ａｒが９２体積％である雰囲気ガス中、６５０℃で３０分間保持し、主に磁石表層部に存在する主相粒子を分解不均化した。 (Example 3)
The sintered magnet obtained by the above step is held at 650 ° C. for 30 minutes in an atmospheric gas containing 8% by volume of N2 and 92% by volume of Ar, and decomposes main phase particles mainly present on the surface layer of the magnet. Disproportionated.

次いで、焼結磁石の全面に対し、ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）をエタノールに分散させたスラリーを、焼結磁石の重量に対するＴｂの重量比が０．５重量％となるように塗布することでＴｂを付着させた。前記スラリーを塗布後に大気圧でＡｒをフローしながら７７０℃で５時間の熱処理を実施し、続いて９５０℃で５時間の熱処理を施しＴｂを粒界拡散させた。 Next, a slurry in which two TbH particles (average particle size D50 = 5 μm) were dispersed in ethanol was added to the entire surface of the sintered magnet so that the weight ratio of Tb to the weight of the sintered magnet was 0.5% by weight. Tb was attached by applying. After the slurry was applied, heat treatment was performed at 770 ° C. for 5 hours while flowing Ar at atmospheric pressure, and then heat treatment was performed at 950 ° C. for 5 hours to diffuse Tb at grain boundaries.

前記熱処理後に冷却速度２００℃／分で急冷し、液相からＲ２Ｔ１４Ｂ結晶を再結晶化させた。 After the heat treatment, the mixture was rapidly cooled at a cooling rate of 200 ° C./min to recrystallize R 2T 14B crystals from the liquid phase.

その後、Ａｒ雰囲気、大気圧中で、５００℃で１時間の再時効処理を行った。 Then, it was re-aged at 500 ° C. for 1 hour in an Ar atmosphere and atmospheric pressure.

前記再時効処理後の焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った。 The magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the sintered magnet after the re-aging treatment were evaluated with a BH tracer.

（実施例４）
上記の工程により得られた焼結磁石を水蒸気分圧２００ｈＰａに調整されたガスを含む酸化性雰囲気中、４００℃で３０分間保持し、主に磁石表層部に存在する主相粒子を分解不均化した。 (Example 4)
The sintered magnet obtained by the above step is held at 400 ° C. for 30 minutes in an oxidizing atmosphere containing a gas adjusted to a partial pressure of water vapor of 200 hPa, and the main phase particles mainly present on the surface layer of the magnet are decomposed and disproportionated. It became.

次いで、焼結磁石の全面に対し、ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）をエタノールに分散させたスラリーを、焼結磁石の重量に対するＴｂの重量比が０．５重量％となるように塗布することでＴｂを付着させた。前記スラリーを塗布後に大気圧でＡｒをフローしながら７７０℃で５時間の熱処理を実施し、続いて９５０℃で５時間の熱処理を施し、Ｔｂを粒界拡散させた。 Next, a slurry in which two TbH particles (average particle size D50 = 5 μm) were dispersed in ethanol was added to the entire surface of the sintered magnet so that the weight ratio of Tb to the weight of the sintered magnet was 0.5% by weight. Tb was attached by applying. After the slurry was applied, heat treatment was performed at 770 ° C. for 5 hours while flowing Ar at atmospheric pressure, and then heat treatment was performed at 950 ° C. for 5 hours to diffuse Tb at grain boundaries.

前記熱処理後に冷却速度２００℃／分で急冷し、液相からＲ２Ｔ１４Ｂ結晶を再結晶化させた。 After the heat treatment, the mixture was rapidly cooled at a cooling rate of 200 ° C./min to recrystallize R 2T 14B crystals from the liquid phase.

その後、Ａｒ雰囲気、大気圧中で、５００℃で１時間の再時効処理を行った。 Then, it was re-aged at 500 ° C. for 1 hour in an Ar atmosphere and atmospheric pressure.

前記再時効処理後の焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った。 The magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the sintered magnet after the re-aging treatment were evaluated with a BH tracer.

（実施例５）
ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）を、ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）およびＮｄＨ２粒子（平均粒径Ｄ５０＝５μｍ）をＴｂ：Ｎｄ＝８０：２０（原子数比）となるように混合させた粒子に置き換える点以外は実施例１と同様に実施した。なお、焼結磁石の重量に対するＴｂの重量が０．５重量％となるようにＴｂおよびＮｄを付着させた。 (Example 5)
TbH 2 particles (average particle size D50 = 5 μm), TbH 2 particles (average particle size D50 = 5 μm) and NdH 2 particles (average particle size D50 = 5 μm) are Tb: Nd = 80: 20 (atomic number ratio). The procedure was carried out in the same manner as in Example 1 except that the particles were replaced with the particles mixed so as to be. Tb and Nd were attached so that the weight of Tb with respect to the weight of the sintered magnet was 0.5% by weight.

（実施例６）
ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）を、ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）およびＮｄＨ２粒子（平均粒径Ｄ５０＝５μｍ）をＴｂ：Ｎｄ＝７０：３０（原子数比）となるように混合させた粒子に置き換える点以外は実施例１と同様に実施した。なお、焼結磁石の重量に対するＴｂの重量が０．５重量％となるようにＴｂおよびＮｄを付着させた。 (Example 6)
TbH 2 particles (average particle size D50 = 5 μm), TbH 2 particles (average particle size D50 = 5 μm) and NdH 2 particles (average particle size D50 = 5 μm) with Tb: Nd = 70: 30 (atomic number ratio). The procedure was carried out in the same manner as in Example 1 except that the particles were replaced with the particles mixed so as to be. Tb and Nd were attached so that the weight of Tb with respect to the weight of the sintered magnet was 0.5% by weight.

（実施例７）
水素が５体積％、Ａｒが９５体積％である雰囲気ガス中での保持時間を２０分間にした点以外は実施例１と同様に実施した。 (Example 7)
The same procedure as in Example 1 was carried out except that the holding time in the atmospheric gas in which hydrogen was 5% by volume and Ar was 95% by volume was set to 20 minutes.

（実施例８）
水素が５体積％、Ａｒが９５体積％である雰囲気ガス中での保持時間を３０分間にした点以外は実施例１と同様に実施した。 (Example 8)
The same procedure as in Example 1 was carried out except that the holding time in the atmospheric gas in which hydrogen was 5% by volume and Ar was 95% by volume was set to 30 minutes.

（実施例９）
熱処理後の冷却速度を５０℃／分にした点以外は実施例１と同様に実施した。 (Example 9)
The same procedure as in Example 1 was carried out except that the cooling rate after the heat treatment was set to 50 ° C./min.

（実施例１０）
熱処理後の冷却速度を５００℃／分にした点以外は実施例１と同様に実施した。 (Example 10)
The same procedure as in Example 1 was carried out except that the cooling rate after the heat treatment was set to 500 ° C./min.

（実施例１１）
ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）を、ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）およびＮｄＨ２粒子（平均粒径Ｄ５０＝５μｍ）をＴｂ：Ｎｄ＝３０：７０（原子数比）となるように混合させた粒子に置き換える点以外は実施例１と同様に実施した。なお、焼結磁石の重量に対するＴｂの重量が０．５重量％となるようにＴｂおよびＮｄを付着させた。 (Example 11)
TbH 2 particles (average particle size D50 = 5 μm), TbH 2 particles (average particle size D50 = 5 μm) and NdH 2 particles (average particle size D50 = 5 μm) are Tb: Nd = 30: 70 (atomic number ratio). The procedure was carried out in the same manner as in Example 1 except that the particles were replaced with the particles mixed so as to be. Tb and Nd were attached so that the weight of Tb with respect to the weight of the sintered magnet was 0.5% by weight.

（実施例１２）
ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）を、ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）およびＮｄＨ２粒子（平均粒径Ｄ５０＝５μｍ）をＴｂ：Ｎｄ＝５０：５０（原子数比）となるように混合させた粒子に置き換える点以外は実施例１と同様に実施した。なお、焼結磁石の重量に対するＴｂの重量が０．５重量％となるようにＴｂおよびＮｄを付着させた。 (Example 12)
TbH 2 particles (average particle size D50 = 5 μm), TbH 2 particles (average particle size D50 = 5 μm) and NdH 2 particles (average particle size D50 = 5 μm) are Tb: Nd = 50: 50 (atomic number ratio). The procedure was carried out in the same manner as in Example 1 except that the particles were replaced with the particles mixed so as to be. Tb and Nd were attached so that the weight of Tb with respect to the weight of the sintered magnet was 0.5% by weight.

（実施例１３）
ＣＯが８体積％、Ａｒが９２体積％である雰囲気ガス中での保持温度を６００℃にした点以外は実施例２と同様に実施した。 (Example 13)
The same procedure as in Example 2 was carried out except that the holding temperature in the atmospheric gas in which CO was 8% by volume and Ar was 92% by volume was set to 600 ° C.

（実施例１４）
スラリーを塗布後に大気圧でＡｒをフローしながら９５０℃で１０時間の熱処理を一回のみ実施してＴｂを粒界拡散させた点以外は実施例１と同様に実施した。 (Example 14)
After the slurry was applied, heat treatment was carried out only once at 950 ° C. for 10 hours while flowing Ar at atmospheric pressure to diffuse Tb at the grain boundaries, and the same procedure as in Example 1 was carried out.

（実施例１５）
ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）を、ＴｂＦ３粒子（平均粒径Ｄ５０＝５μｍ）に置き換える点以外は実施例１と同様に実施した。なお、焼結磁石の重量に対するＴｂの重量が０．５重量％となるようにＴｂを付着させた。 (Example 15)
The procedure was carried out in the same manner as in Example 1 except that the TbH 2 particles (average particle size D50 = 5 μm) were replaced with the TbF 3 particles (average particle size D50 = 5 μm). The Tb was attached so that the weight of the Tb with respect to the weight of the sintered magnet was 0.5% by weight.

（実施例１６）
ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）を、Ｔｂ２Ｏ３粒子（平均粒径Ｄ５０＝５μｍ）に置き換える点以外は実施例１と同様に実施した。なお、焼結磁石の重量に対するＴｂの重量が０．５重量％となるようにＴｂを付着させた。 (Example 16)
The procedure was carried out in the same manner as in Example 1 except that the TbH 2 particles (average particle size D50 = 5 μm) were replaced with Tb 2 O 3 particles (average particle size D50 = 5 μm). The Tb was attached so that the weight of the Tb with respect to the weight of the sintered magnet was 0.5% by weight.

（実施例１７）
ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）を、Ｔｂ－Ｆｅ化合物［Ｔｂ：Ｆｅ＝８０：２０（原子数比）］（平均粒径Ｄ５０＝５μｍ）に置き換える点以外は実施例１と同様に実施した。なお、焼結磁石の重量に対するＴｂの重量が０．５重量％となるようにＴｂを付着させた。 (Example 17)
Same as Example 1 except that the TbH 2 particles (average particle size D50 = 5 μm) are replaced with the Tb—Fe compound [Tb: Fe = 80: 20 (atomic number ratio)] (average particle size D50 = 5 μm). Carried out. The Tb was attached so that the weight of the Tb with respect to the weight of the sintered magnet was 0.5% by weight.

（実施例１８）
ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）を、ＤｙＨ２粒子（平均粒径Ｄ５０＝５μｍ）に置き換える点以外は実施例１と同様に実施した。なお、焼結磁石の重量に対するＤｙの重量が０．５重量％となるようにＤｙを付着させた。 (Example 18)
The procedure was carried out in the same manner as in Example 1 except that the TbH 2 particles (average particle size D50 = 5 μm) were replaced with DyH 2 particles (average particle size D50 = 5 μm). Dy was attached so that the weight of Dy with respect to the weight of the sintered magnet was 0.5% by weight.

（実施例１９）
ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）を、ＤｙＦ３粒子（平均粒径Ｄ５０＝５μｍ）に置き換える点以外は実施例１と同様に実施した。なお、焼結磁石の重量に対するＤｙの重量が０．５重量％となるようにＤｙを付着させた。 (Example 19)
The procedure was carried out in the same manner as in Example 1 except that the TbH 2 particles (average particle size D50 = 5 μm) were replaced with DyF 3 particles (average particle size D50 = 5 μm). Dy was attached so that the weight of Dy with respect to the weight of the sintered magnet was 0.5% by weight.

（実施例２０）
ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）を、Ｄｙ－Ｆｅ化合物［Ｄｙ：Ｆｅ＝８０：２０（原子数比）］（平均粒径Ｄ５０＝５μｍ）に置き換える点以外は実施例１と同様に実施した。なお、焼結磁石の重量に対するＤｙの重量が０．５重量％となるようにＤｙを付着させた。 (Example 20)
Same as Example 1 except that the TbH 2 particles (average particle size D50 = 5 μm) are replaced with the Dy—Fe compound [Dy: Fe = 80: 20 (atomic number ratio)] (average particle size D50 = 5 μm). Carried out. Dy was attached so that the weight of Dy with respect to the weight of the sintered magnet was 0.5% by weight.

（実施例２１）
実施例２１では、粒界拡散前の焼結磁石の組成が表１に示す組成となるようにした点以外は実施例１と同様に実施した。具体的には、原料合金Ｇを作製した。そして、実施例１と同様に粉砕、成形、焼結および時効処理を行い、表２に示す組成の焼結磁石を得た。その後、実施例１と同様に磁石表層部に存在する主相粒子を分解不均化させ、Ｔｂの拡散処理を実施した。その後、実施例１と同様に再結晶化および再時効処理を施した。前記再時効処理後の焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った。 (Example 21)
In Example 21, the same procedure as in Example 1 was carried out except that the composition of the sintered magnet before the grain boundary diffusion was set to the composition shown in Table 1. Specifically, the raw material alloy G was produced. Then, crushing, molding, sintering and aging treatment were carried out in the same manner as in Example 1 to obtain a sintered magnet having the composition shown in Table 2. Then, as in Example 1, the main phase particles existing on the surface layer of the magnet were decomposed and disproportionated, and the diffusion treatment of Tb was carried out. Then, it was recrystallized and re-aged in the same manner as in Example 1. The magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the sintered magnet after the re-aging treatment were evaluated with a BH tracer.

（実施例２２）
実施例２２では、粒界拡散前の焼結磁石の組成が表１に示す組成となるようにした点以外は実施例１と同様に実施した。具体的には、原料合金Ｈを作製した。そして、実施例１と同様に粉砕、成形、焼結および時効処理を行い、表２に示す組成の焼結磁石を得た。その後、実施例１と同様に磁石表層部に存在する主相粒子を分解不均化させ、Ｔｂの拡散処理を実施した。その後、実施例１と同様に再結晶化および再時効処理を施した。前記再時効処理後の焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った。 (Example 22)
In Example 22, the same procedure as in Example 1 was carried out except that the composition of the sintered magnet before the grain boundary diffusion was set to the composition shown in Table 1. Specifically, the raw material alloy H was produced. Then, crushing, molding, sintering and aging treatment were carried out in the same manner as in Example 1 to obtain a sintered magnet having the composition shown in Table 2. Then, as in Example 1, the main phase particles existing on the surface layer of the magnet were decomposed and disproportionated, and the diffusion treatment of Tb was carried out. Then, it was recrystallized and re-aged in the same manner as in Example 1. The magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the sintered magnet after the re-aging treatment were evaluated with a BH tracer.

（比較例１）
上記の焼結磁石作製工程により得られた焼結磁石全面に対し、ＴｂＨ２粒子（平均粒径Ｄ５０＝５μｍ）をエタノールに分散させたスラリーを、焼結磁石の重量に対するＴｂの重量が０．５重量％となるように塗布することでＴｂを付着させた。前記スラリーを塗布後に大気圧でＡｒをフローしながら７７０℃で５時間の熱処理を実施し、続いて９５０℃で５時間の熱処理を施し、Ｔｂを粒界拡散させた。そして、前記熱処理後に冷却速度２００℃／分で急冷した。 (Comparative Example 1)
A slurry in which two TbH particles (average particle size D50 = 5 μm) are dispersed in ethanol on the entire surface of the sintered magnet obtained by the above-mentioned sintering magnet manufacturing step, the weight of Tb with respect to the weight of the sintered magnet is 0. Tb was attached by applying so as to be 5% by weight. After the slurry was applied, heat treatment was performed at 770 ° C. for 5 hours while flowing Ar at atmospheric pressure, and then heat treatment was performed at 950 ° C. for 5 hours to diffuse Tb at grain boundaries. Then, after the heat treatment, the mixture was rapidly cooled at a cooling rate of 200 ° C./min.

その後、Ａｒ雰囲気、大気圧中で、５００℃で１時間の再時効処理を行った。 Then, it was re-aged at 500 ° C. for 1 hour in an Ar atmosphere and atmospheric pressure.

前記再時効処理後の焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った。 The magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the sintered magnet after the re-aging treatment were evaluated with a BH tracer.

（比較例２）
比較例２では、焼結磁石作製工程において、表１に示す組成となるように焼結体用合金（原料合金）ＢおよびＣを作製した。表１に示す原料合金Ｂおよび原料合金Ｃを水素粉砕した後に、重量比で９：１となるように混合した。その後、実施例１と同様に微粉砕、成形、焼結および時効処理を行い、表２に示す組成を有する焼結磁石を得た。なお、当該焼結磁石の組成は、上記拡散処理後の実施例１～４，７～１０および比較例１の焼結磁石の組成と同一になることを確認した。 (Comparative Example 2)
In Comparative Example 2, in the sintered magnet manufacturing step, the sintered body alloys (raw material alloys) B and C were manufactured so as to have the compositions shown in Table 1. The raw material alloy B and the raw material alloy C shown in Table 1 were hydrogen-pulverized and then mixed so as to have a weight ratio of 9: 1. Then, pulverization, molding, sintering and aging treatment were carried out in the same manner as in Example 1 to obtain a sintered magnet having the composition shown in Table 2. It was confirmed that the composition of the sintered magnet was the same as the composition of the sintered magnets of Examples 1 to 4, 7 to 10 and Comparative Example 1 after the diffusion treatment.

前記時効処理後の焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った。 The magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the sintered magnet after the aging treatment were evaluated with a BH tracer.

（比較例３）
比較例３では、ストリップキャスト法により、後述する表２に示す組成となるように焼結体用合金（原料合金）ＤおよびＥを作製した。表２に示す原料合金Ｄおよび原料合金Ｅを水素粉砕した後に、重量比で９：１となるように混合した。その後、実施例１と同様に微粉砕、成形、焼結および時効処理を行い、表２に示す組成の焼結磁石を得た。 (Comparative Example 3)
In Comparative Example 3, sintered alloys (raw material alloys) D and E were produced by the strip casting method so as to have the compositions shown in Table 2 described later. The raw material alloy D and the raw material alloy E shown in Table 2 were hydrogen-pulverized and then mixed so as to have a weight ratio of 9: 1. Then, pulverization, molding, sintering and aging treatment were carried out in the same manner as in Example 1 to obtain a sintered magnet having the composition shown in Table 2.

前記時効処理後の焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った。 The magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the sintered magnet after the aging treatment were evaluated with a BH tracer.

（比較例４）
比較例４では、最終的に得られる焼結磁石の組成が表１に示す組成となるようにした点以外は実施例１と同様に焼結体用合金（原料合金）を作製した。具体的には、原料合金Ｆを作製した。そして、実施例１と同様に粉砕、成形、焼結および時効処理を行い、表２に示す組成の焼結磁石を得た。 (Comparative Example 4)
In Comparative Example 4, an alloy for a sintered body (raw material alloy) was produced in the same manner as in Example 1 except that the composition of the sintered magnet finally obtained was the composition shown in Table 1. Specifically, the raw material alloy F was produced. Then, crushing, molding, sintering and aging treatment were carried out in the same manner as in Example 1 to obtain a sintered magnet having the composition shown in Table 2.

前記時効処理後の焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った。 The magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the sintered magnet after the aging treatment were evaluated with a BH tracer.

（比較例５）
拡散処理後の再結晶化工程における冷却速度を１０℃／分にした点以外は実施例１と同様に実施した。 (Comparative Example 5)
The same procedure as in Example 1 was carried out except that the cooling rate in the recrystallization step after the diffusion treatment was set to 10 ° C./min.

（比較例６）
比較例６では粒界拡散前の焼結磁石の組成が表１に示す組成となるようにして得られた焼結磁石全面に対し、ＤｙＨ２粒子（平均粒径Ｄ５０＝５μｍ）をエタノールに分散させたスラリーを、焼結磁石の重量に対するＤｙの重量が１．０重量％となるように塗布することでＤｙを付着させた。前記スラリーを塗布後に大気圧でＡｒをフローしながら７７０℃で５時間の熱処理を実施し、続いて９５０℃で５時間の熱処理を施し、Ｄｙを粒界拡散させた。そして、前記熱処理後に冷却速度２００℃／分で急冷した。 その後、Ａｒ雰囲気、大気圧中で、５００℃で１時間の再時効処理を行った。前記再時効処理後の焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った。 (Comparative Example 6)
In Comparative Example 6, DyH 2 particles (average particle size D50 = 5 μm) were dispersed in ethanol on the entire surface of the sintered magnet obtained so that the composition of the sintered magnet before diffusion of the grain boundaries had the composition shown in Table 1. Dy was attached by applying the obtained slurry so that the weight of Dy with respect to the weight of the sintered magnet was 1.0% by weight. After the slurry was applied, heat treatment was performed at 770 ° C. for 5 hours while flowing Ar at atmospheric pressure, and then heat treatment was performed at 950 ° C. for 5 hours to diffuse Dy at the grain boundaries. Then, after the heat treatment, the mixture was rapidly cooled at a cooling rate of 200 ° C./min. Then, it was re-aged at 500 ° C. for 1 hour in an Ar atmosphere and atmospheric pressure. The magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the sintered magnet after the re-aging treatment were evaluated with a BH tracer.

表３には、焼結磁石の表層部に存在する主相粒子を分解する分解処理を行ったか、粒界拡散処理を行ったか、そして、粒界拡散後に急冷を行ったかのそれぞれについて記載した。各処理を行った場合には〇、各処理を行わなかった場合には×を付けた。 Table 3 describes whether the decomposition treatment was performed to decompose the main phase particles existing on the surface layer of the sintered magnet, the grain boundary diffusion treatment was performed, and whether the quenching was performed after the grain boundary diffusion. When each process was performed, it was marked with 〇, and when each process was not performed, it was marked with ×.

各実施例および比較例のＲ－Ｔ－Ｂ系焼結磁石について、ＢＨトレーサーで磁気特性（残留磁束密度Ｂｒ、保磁力Ｈｃｊおよび角形比Ｈｋ／Ｈｃｊ）の評価を行った結果を表３に示す。なお、残留磁束密度Ｂｒは１３８０ｍＴ以上を良好とし、１４００ｍＴ以上をさらに良好とした。保磁力ＨｃｊはＴｂを粒界拡散させた場合には１８００ｋＡ／ｍ以上を良好とし、１８３０ｋＡ／ｍ以上をさらに良好とした。Ｄｙを粒界拡散させた場合には１６００ｋＡ／ｍ以上を良好とし、１６２０ｋＡ／ｍ以上をさらに良好とした。角形比Ｈｋ／Ｈｃｊは０．９０を超える場合を良好とし、０．９５以上である場合をさらに良好とした。 Table 3 shows the results of evaluation of the magnetic characteristics (residual magnetic flux density Br, coercive force Hcj and square ratio Hk / Hcj) of the RTB-based sintered magnets of each Example and Comparative Example with a BH tracer. .. The residual magnetic flux density Br was good at 1380 mT or more, and further good at 1400 mT or more. The coercive force Hcj was good at 1800 kA / m or more when Tb was diffused at the grain boundaries, and further good at 1830 kA / m or more. When Dy was diffused at the grain boundaries, 1600 kA / m or more was good, and 1620 kA / m or more was even better. When the square ratio Hk / Hcj exceeds 0.90, it is considered to be good, and when it is 0.95 or more, it is further considered to be good.

また、各実施例および比較例のＲ－Ｔ－Ｂ系焼結磁石を任意の断面で切断し、当該断面を観察した。磁石表層部のうち、磁石表面から磁石内部に向かって２０μｍの部分における逆コアシェル主相粒子の存在割合を測定した。磁石表層部における逆コアシェル主相粒子の存在割合の測定は、磁石表層部のうち、磁石表面から磁石内部に向かって２０μｍの部分にある主相粒子からランダムに選んだ１０個の主相粒子についてＳＥＭおよびＴＥＭ－ＥＤＳを用いて行った。また、磁石中央部における逆コアシェル主相粒子の存在割合を測定した。磁石中央部における逆コアシェル主相粒子の存在割合の測定は、磁石中央部にある主相粒子の中からランダムに選んだ１０個の主相粒子についてＳＥＭおよびＴＥＭ－ＥＤＳを用いて行った。結果を表４に示す。 Further, the RTB-based sintered magnets of each Example and Comparative Example were cut at an arbitrary cross section, and the cross section was observed. The abundance ratio of the inverted core shell main phase particles in the portion of the magnet surface layer portion 20 μm from the magnet surface toward the inside of the magnet was measured. The abundance ratio of the inverted core shell main phase particles in the magnet surface layer is measured for 10 main phase particles randomly selected from the main phase particles located 20 μm from the magnet surface toward the inside of the magnet in the magnet surface layer. This was done using SEM and TEM-EDS. In addition, the abundance ratio of the inverted core shell main phase particles in the central part of the magnet was measured. The abundance ratio of the inverted core shell main phase particles in the central part of the magnet was measured using SEM and TEM-EDS for 10 main phase particles randomly selected from the main phase particles in the central part of the magnet. The results are shown in Table 4.

さらに、各実施例において磁石表層部に存在する逆コアシェル主相粒子について、コア部における全ＲＨの濃度ＣＲＣおよびシェル部におけるにおける全ＲＨの濃度ＣＲＳを測定した。そして、各逆コアシェル主相粒子におけるＣＲＣ／ＣＲＳ＞１．５である粒子の割合およびＣＲＣ／ＣＲＳ＞３．０である粒子の割合をＴＥＭ－ＥＤＳを用いて算出した。結果を表４に示す。 Furthermore, for the reverse core shell main phase particles present on the surface layer of the magnet in each example, the concentration CRC of the total RH in the core portion and the concentration CRS of the total RH in the shell portion were measured. Then, the proportion of particles having C RC / C RS > 1.5 and the proportion of particles having C RC / C RS > 3.0 in each inverted core-shell main phase particle were calculated using TEM-EDS. The results are shown in Table 4.

本実施例における逆コアシェル主相粒子１１において、コア部１１ａにおける全ＲＨ濃度およびシェル部１１ｂにおける全ＲＨ濃度の測定箇所は以下の通りとする。 In the inverted core-shell main phase particles 11 in this embodiment, the measurement points of the total RH concentration in the core portion 11a and the total RH concentration in the shell portion 11b are as follows.

まず、濃度を測定する逆コアシェル主相粒子１１を透過型電子顕微鏡（ＴＥＭ）で観察し、長さが最大となる直径を特定する。次に、当該直径と粒界との二つの交点を特定する。そして、当該二つの交点の中点を中心とする２０ｎｍ×２０ｎｍの領域における全ＲＨ濃度を測定し、コア部における全ＲＨ濃度ＣＲＣとする。 First, the inverted core-shell main phase particles 11 for measuring the concentration are observed with a transmission electron microscope (TEM), and the diameter at which the length is maximized is specified. Next, the two intersections of the diameter and the grain boundary are specified. Then, the total RH concentration in the region of 20 nm × 20 nm centered on the midpoint of the two intersections is measured and used as the total RH concentration C RC in the core portion.

次に、当該二つの交点のうち一つの交点を選択する。そして、当該交点から前記長さが最大となる直径に沿って２０ｎｍ、逆コアシェル主相粒子側に侵入した点を中心とする２０ｎｍ×２０ｎｍの領域における全ＲＨ濃度を測定し、シェル部における全ＲＨ濃度ＣＲＳとする。 Next, one of the two intersections is selected. Then, the total RH concentration in the region of 20 nm × 20 nm centered on the point invading the reverse core shell main phase particle side at 20 nm along the diameter at which the length becomes maximum from the intersection is measured, and the total RH in the shell portion is measured. Let the concentration be C RS .

さらに、磁石表層部におけるコアシェル主相粒子の存在割合を測定した。磁石表層部におけるコアシェル主相粒子の存在割合は、磁石表層部のうち、磁石表面から磁石内部に向かって２０μｍの部分にある主相粒子の中からランダムに選んだ１０粒子についてＳＥＭおよびＴＥＭ－ＥＤＳを用いて測定した。また、磁石中央部におけるコアシェル粒子の存在割合を測定した。磁石中央部におけるコアシェル主相粒子の存在割合は、磁石中央部にある主相粒子の中からランダムに選んだ１０粒子についてＳＥＭおよびＴＥＭ－ＥＤＳを用いて測定した。結果を表４に示す。 Furthermore, the abundance ratio of the core-shell main phase particles in the surface layer of the magnet was measured. The abundance ratio of core-shell main phase particles in the magnet surface layer is SEM and TEM-EDS for 10 particles randomly selected from the main phase particles located 20 μm from the magnet surface toward the inside of the magnet in the magnet surface layer. Was measured using. In addition, the abundance ratio of core-shell particles in the central part of the magnet was measured. The abundance ratio of the core-shell main phase particles in the central part of the magnet was measured by using SEM and TEM-EDS for 10 particles randomly selected from the main phase particles in the central part of the magnet. The results are shown in Table 4.

さらに、各実施例について、逆コアシェル粒子層の厚み、コアシェル粒子層の厚みおよび非コアシェル粒子層の厚みについて、ＳＥＭを用いて測定した。結果を表４に示す。なお、各層の厚みは１層あたりの厚みである。各層が２層以上存在する場合には、平均を算出して平均値を各層の厚みとした。 Furthermore, for each example, the thickness of the inverted core-shell particle layer, the thickness of the core-shell particle layer, and the thickness of the non-core-shell particle layer were measured using SEM. The results are shown in Table 4. The thickness of each layer is the thickness per layer. When there were two or more layers, the average was calculated and the average value was taken as the thickness of each layer.

以下、上記の各層の厚みを測定する方法について、さらに具体的に説明する。各実施例および比較例のＲ－Ｔ－Ｂ系焼結磁石を配向方向と平行な断面で切断し、当該断面を鏡面研磨した後、電子顕微鏡（ＳＥＭ）にて１０００倍で観察した。ＳＥＭ観察は配向方向に沿って、磁石表面から逆側の磁石表面まで連続的に行った。観察した視野の中で逆コアシェル粒子が観察され始めてから観察されなくなるまでの領域を主に逆コアシェル主相粒子からなる逆コアシェル粒子層とした。そして、逆コアシェル粒子層の厚みをＳＥＭ画像から概算した。また、観察した視野の中で逆コアシェル粒子が観察されなくなってからコアシェル粒子が観察されなくなるまでの領域を、主にコアシェル主相粒子からなるコアシェル粒子層とした。そして、コアシェル粒子相の厚みを概算した。さらに、観察した視野の中で逆コアシェル粒子およびコアシェル粒子が観察されない領域を非コアシェル主相粒子からなる非コアシェル粒子層とした。そして、非コアシェル粒子層の厚みを概算した。 Hereinafter, the method of measuring the thickness of each of the above layers will be described more specifically. The RTB-based sintered magnets of each Example and Comparative Example were cut in a cross section parallel to the orientation direction, the cross section was mirror-polished, and then observed with an electron microscope (SEM) at a magnification of 1000. SEM observation was continuously performed from the magnet surface to the magnet surface on the opposite side along the orientation direction. The region from the beginning of the observation of the reverse core-shell particles to the absence of the reverse core-shell particles in the observed field of view was defined as the reverse-core-shell particle layer mainly composed of the reverse-core-shell main phase particles. Then, the thickness of the inverted core-shell particle layer was estimated from the SEM image. In addition, the region from when the inverted core-shell particles are no longer observed to when the core-shell particles are no longer observed in the observed field of view is defined as a core-shell particle layer mainly composed of core-shell main phase particles. Then, the thickness of the core-shell particle phase was estimated. Further, the region where the inverted core-shell particles and the core-shell particles were not observed in the observed field of view was defined as a non-core-shell particle layer composed of non-core-shell main phase particles. Then, the thickness of the non-core shell particle layer was estimated.

Figure 0007035682000001
Figure 0007035682000001

Figure 0007035682000002
Figure 0007035682000002

Figure 0007035682000003
Figure 0007035682000003

Figure 0007035682000004
Figure 0007035682000004

表１～表４より、焼結後に磁石表層部の主相粒子を分解不均化する工程、粒界拡散により液相を生成させ、液相にＲＨを取り込ませる工程、および、急冷によりＲＨが取り込まれた液相を再結晶化する工程を経た実施例１～２２のＲ－Ｔ－Ｂ系焼結磁石は逆コアシェル主相粒子が磁石表層部に生成して逆コアシェル粒子層を形成した。そして、残留磁束密度、保磁力および角形比が好ましい結果となった。 From Tables 1 to 4, from Tables 1 to 4, a step of decomposing and disproportionating the main phase particles of the magnet surface layer portion after sintering, a step of generating a liquid phase by intergranular diffusion and incorporating RH into the liquid phase, and a step of incorporating RH into the liquid phase, and RH by quenching. In the RTB-based sintered magnets of Examples 1 to 22 that have undergone the step of recrystallizing the taken-in liquid phase, reverse core shell main phase particles are generated on the magnet surface layer portion to form a reverse core shell particle layer. The residual magnetic flux density, coercive force and square ratio were favorable results.

さらに、Ｔｂを粒界拡散した実施例のうち、逆コアシェル粒子層の厚みが１０μｍ以上６０μｍ以下であり、ＣＲＣ／ＣＲＳ＞１．５である逆コアシェル粒子が存在する実施例１～７，９～１０，１２～１７および２１～２２は残留磁束密度がさらに好ましい結果となった。 Further, among the examples in which Tb is diffused at the grain boundaries, Examples 1 to 7 in which the thickness of the reverse core shell particle layer is 10 μm or more and 60 μm or less and the reverse core shell particles having C RC / C RS > 1.5 are present are present. For 9 to 10, 12 to 17 and 21 to 22, the residual magnetic flux density was more preferable.

これに対し、焼結後に磁石表層部の主相粒子を分解不均化する工程、粒界拡散により液相を生成させ、液相にＲＨを取り込ませる工程、および、急冷によりＲＨが取り込まれた液相を再結晶化する工程を経なかった比較例では、逆コアシェル主相粒子が生成しなかった。その結果、残留磁束密度、保磁力および／または角形比が実施例１～２２より劣る結果となった。 On the other hand, a step of decomposing and disproportionating the main phase particles on the surface layer of the magnet after sintering, a step of generating a liquid phase by intergranular diffusion, and a step of incorporating RH into the liquid phase, and RH being incorporated by quenching. In the comparative example which did not undergo the step of recrystallizing the liquid phase, the reverse core shell main phase particles were not generated. As a result, the residual magnetic flux density, coercive force and / or square ratio were inferior to those of Examples 1 to 22.

比較例１および６では焼結後に磁石表層部の主相粒子を分解不均化する工程を行わなかったため、粒界拡散および急冷を経ても逆コアシェル主相粒子が生成しなかった。比較例２では、２合金法により焼結磁石を作製したが、逆コアシェル主相粒子が生成しなかった。その結果、残留磁束密度および保磁力が実施例１～１７および２１～２２より劣る結果となった。比較例３および４では、Ｔｂの含有量を増加させた結果、保磁力は良好となったが残留磁束密度が実施例１～１７および２１～２２よりも劣る結果となった。また、Ｔｂの含有量が増加しているため、比較例３および４の焼結磁石は製造コストも実施例１～１７および２１～２２の焼結磁石より高価となった。比較例５では、拡散処理後の再結晶化工程における冷却速度が低すぎたため、均一な主相粒子となってしまい、逆コアシェル主相粒子が生成しなかった。 In Comparative Examples 1 and 6, since the step of decomposing and disproportionating the main phase particles on the surface layer of the magnet was not performed after sintering, the reverse core shell main phase particles were not generated even after the intergranular diffusion and quenching. In Comparative Example 2, a sintered magnet was produced by a two-alloy method, but reverse core-shell main phase particles were not generated. As a result, the residual magnetic flux density and the coercive force were inferior to those of Examples 1 to 17 and 21 to 22. In Comparative Examples 3 and 4, as a result of increasing the Tb content, the coercive force was good, but the residual magnetic flux density was inferior to that of Examples 1 to 17 and 21 to 22. Further, since the content of Tb is increased, the sintered magnets of Comparative Examples 3 and 4 are more expensive to manufacture than the sintered magnets of Examples 1 to 17 and 21 to 22. In Comparative Example 5, since the cooling rate in the recrystallization step after the diffusion treatment was too low, the particles became uniform main phase particles, and the reverse core shell main phase particles were not generated.

１，１０…Ｒ－Ｔ－Ｂ系焼結磁石
１ａ…逆コアシェル粒子層
１ｂ…コアシェル粒子層
１ｃ…非コアシェル粒子層
１１…逆コアシェル主相粒子
１１ａ…コア部（逆コアシェル主相粒子）
１１ｂ…シェル部（逆コアシェル主相粒子）
１２…粒界
１３…コアシェル主相粒子
１３ａ…コア部（コアシェル主相粒子）
１３ｂ…シェル部（コアシェル主相粒子） 1,10 ... RTB-based sintered magnet 1a ... Reverse core shell particle layer 1b ... Core shell particle layer 1c ... Non-core shell particle layer 11 ... Reverse core shell main phase particles 11a ... Core part (reverse core shell main phase particles)
11b ... Shell part (reverse core shell main phase particles)
12 ... Grain boundaries 13 ... Core-shell main phase particles 13a ... Core part (core-shell main phase particles)
13b ... Shell part (core shell main phase particles)

Claims (6)

Ｒ２Ｔ１４Ｂ結晶からなる主相粒子を含むＲ－Ｔ－Ｂ系焼結磁石であって、
Ｒは重希土類元素ＲＨを必須とする１種以上の希土類元素、ＴはＦｅまたはＦｅおよびＣｏを必須とする１種以上の遷移金属元素、Ｂはホウ素であり、
前記主相粒子の一部が逆コアシェル主相粒子であり、
前記逆コアシェル主相粒子は、コア部およびシェル部を有し、
前記コア部における全ＲＨ濃度（ａｔ％）をＣＲＣ、
前記シェル部における全ＲＨ濃度（ａｔ％）をＣＲＳとした場合に、
ＣＲＣ／ＣＲＳ＞１．５であり、
前記逆コアシェル主相粒子の存在比率が、磁石中央部よりも磁石表層部の方が大きいことを特徴とするＲ－Ｔ－Ｂ系焼結磁石。 An RTB-based sintered magnet containing main phase particles composed of R 2 T 14 B crystals.
R is one or more rare earth elements that require the heavy rare earth element RH, T is one or more transition metal elements that require Fe or Fe and Co, and B is boron.
Some of the main phase particles are reverse core shell main phase particles.
The reverse core-shell main phase particles have a core portion and a shell portion, and have a core portion and a shell portion.
The total RH concentration (at%) in the core portion is C RC ,
When the total RH concentration (at%) in the shell portion is CRS ,
C RC / C RS > 1.5 ,
An RTB-based sintered magnet characterized in that the abundance ratio of the reverse core shell main phase particles is larger in the magnet surface layer portion than in the magnet central portion. 前記主相粒子の一部がコアシェル主相粒子であり、
前記コアシェル主相粒子は、コア部およびシェル部を有し、
前記コア部における全ＲＨ濃度（ａｔ％）をＣＮＣ、
前記シェル部における全ＲＨ濃度（ａｔ％）をＣＮＳとした場合に、
ＣＮＣ／ＣＮＳ＜１．０であることを特徴とする請求項１に記載のＲ－Ｔ－Ｂ系焼結磁石。 Some of the main phase particles are core shell main phase particles.
The core-shell main phase particles have a core portion and a shell portion, and have a core portion and a shell portion.
The total RH concentration (at%) in the core part is CNC ,
When the total RH concentration (at%) in the shell portion is CNS ,
The RTB-based sintered magnet according to claim 1 , wherein C NC / C NS <1.0. 主に前記コアシェル主相粒子からなるコアシェル粒子層、および、主に前記逆コアシェル主相粒子からなる逆コアシェル粒子層を含む請求項２に記載のＲ－Ｔ－Ｂ系焼結磁石。 The RTB-based sintered magnet according to claim 2 , further comprising a core-shell particle layer mainly composed of the core-shell main phase particles and a reverse core-shell particle layer mainly composed of the reverse core-shell main phase particles. Ｒ２Ｔ１４Ｂ結晶からなる主相粒子を含むＲ－Ｔ－Ｂ系焼結磁石であって、
Ｒは重希土類元素ＲＨを必須とする１種以上の希土類元素、ＴはＦｅまたはＦｅおよびＣｏを必須とする１種以上の遷移金属元素、Ｂはホウ素であり、
前記主相粒子の一部が逆コアシェル主相粒子であり、
前記逆コアシェル主相粒子は、コア部およびシェル部を有し、
前記コア部における全ＲＨ濃度（ａｔ％）をＣＲＣ、
前記シェル部における全ＲＨ濃度（ａｔ％）をＣＲＳとした場合に、
ＣＲＣ／ＣＲＳ＞１．０であり、
前記逆コアシェル主相粒子の存在比率が、磁石中央部よりも磁石表層部の方が大きく、
前記主相粒子の一部がコアシェル主相粒子であり、
前記コアシェル主相粒子は、コア部およびシェル部を有し、
前記コア部における全ＲＨ濃度（ａｔ％）をＣ ＮＣ 、
前記シェル部における全ＲＨ濃度（ａｔ％）をＣ ＮＳ とした場合に、
Ｃ ＮＣ ／Ｃ ＮＳ ＜１．０であり、
主に前記コアシェル主相粒子からなるコアシェル粒子層、および、主に前記逆コアシェル主相粒子からなる逆コアシェル粒子層を含むことを特徴とするＲ－Ｔ－Ｂ系焼結磁石。 An RTB-based sintered magnet containing main phase particles composed of R 2 T 14 B crystals.
R is one or more rare earth elements that require the heavy rare earth element RH, T is one or more transition metal elements that require Fe or Fe and Co, and B is boron.
Some of the main phase particles are reverse core shell main phase particles.
The reverse core-shell main phase particles have a core portion and a shell portion, and have a core portion and a shell portion.
The total RH concentration (at%) in the core portion is C RC ,
When the total RH concentration (at%) in the shell portion is CRS ,
C RC / C RS > 1.0,
The abundance ratio of the reverse core shell main phase particles is larger in the magnet surface layer than in the magnet center.
Some of the main phase particles are core shell main phase particles.
The core-shell main phase particles have a core portion and a shell portion, and have a core portion and a shell portion.
The total RH concentration (at%) in the core part is CNC ,
When the total RH concentration (at%) in the shell portion is CNS ,
C NC / C NS <1.0,
An RTB-based sintered magnet comprising a core-shell particle layer mainly composed of the core-shell main phase particles and a reverse core-shell particle layer mainly composed of the reverse core-shell main phase particles . 磁石中央部から磁石表層部に向かって、前記コアシェル粒子層および前記逆コアシェル粒子層がこの順番に並んでいる請求項３または４に記載のＲ－Ｔ－Ｂ系焼結磁石。 The RTB-based sintered magnet according to claim 3 or 4 , wherein the core-shell particle layer and the reverse core-shell particle layer are arranged in this order from the central portion of the magnet toward the surface layer portion of the magnet. 前記主相粒子の一部がコアシェル構造を有さない非コアシェル主相粒子であって、主に前記非コアシェル主相粒子からなる非コアシェル粒子層を含むＲ－Ｔ－Ｂ系焼結磁石であって、
磁石中央部から磁石表層部に向かって、前記非コアシェル粒子層、前記コアシェル粒子層および前記逆コアシェル粒子層がこの順番に並んでいる請求項３または４に記載のＲ－Ｔ－Ｂ系焼結磁石。 A part of the main phase particles is a non-core shell main phase particle having no core shell structure, and is an RTB-based sintered magnet containing a non-core shell particle layer mainly composed of the non-core shell main phase particles. hand,
The RTB-based sintering according to claim 3 or 4 , wherein the non-core shell particle layer, the core shell particle layer, and the reverse core shell particle layer are arranged in this order from the central portion of the magnet toward the surface layer portion of the magnet. magnet.
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