JP6798546B2 - Manufacturing method of RTB-based sintered magnet - Google Patents

Manufacturing method of RTB-based sintered magnet Download PDF

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JP6798546B2
JP6798546B2 JP2018505902A JP2018505902A JP6798546B2 JP 6798546 B2 JP6798546 B2 JP 6798546B2 JP 2018505902 A JP2018505902 A JP 2018505902A JP 2018505902 A JP2018505902 A JP 2018505902A JP 6798546 B2 JP6798546 B2 JP 6798546B2
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sintered magnet
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JPWO2017159576A1 (en
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倫太郎 石井
倫太郎 石井
鉄兵 佐藤
鉄兵 佐藤
國吉　太
太 國吉
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets

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  • Mechanical Engineering (AREA)
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Description

本開示は、Ｒ−Ｔ−Ｂ系焼結磁石の製造方法に関する。 The present disclosure relates to a method for manufacturing an RTB-based sintered magnet.

Ｒ−Ｔ−Ｂ系焼結磁石（Ｒは希土類元素のうち少なくとも一種であり、ＮｄおよびＰｒの少なくとも一種を含む、Ｔは遷移金属元素のうち少なくとも一種でありＦｅを必ず含む）は、Ｒ２Ｔ１４Ｂ型結晶構造を有する化合物からなる主相と、この主相の粒界部分に位置する粒界相とから構成されており、永久磁石の中で最も高性能な磁石として知られている。R-TB based sintered magnets (R is at least one of rare earth elements and contains at least one of Nd and Pr, T is at least one of transition metal elements and always contains Fe) are R 2 It is composed of a main phase composed of a compound having a T 14 B type crystal structure and a grain boundary phase located at the grain boundary portion of this main phase, and is known as the highest performance magnet among permanent magnets. ..

このため、ハードディスクドライブのボイスコイルモータ（ＶＣＭ）、電気自動車（ＥＶ、ＨＶ、ＰＨＶ）用モータ、産業機器用モータなどの各種モータや家電製品など多種多様な用途に用いられている。 Therefore, it is used in a wide variety of applications such as various motors such as voice coil motors (VCM) for hard disk drives, motors for electric vehicles (EV, HV, PHV), motors for industrial equipment, and home appliances.

このように用途が広がるにつれ、例えば電気自動車用モータは、１００℃〜１６０℃のような高温下に曝される場合があり、高温下においても安定した動作が要求されている。 As the applications are expanded in this way, for example, motors for electric vehicles may be exposed to high temperatures such as 100 ° C. to 160 ° C., and stable operation is required even at high temperatures.

しかし、従来のＲ−Ｔ−Ｂ系焼結磁石は、高温になると保磁力ＨｃＪ（以下、単に「ＨｃＪ」と記載する場合がある）が低下し、不可逆熱減磁が起こるという問題がある。電気自動車用モータにＲ−Ｔ−Ｂ系焼結磁石が使用される場合、高温下での使用によりＨｃＪが低下し、モータの安定した動作が得られない恐れがある。そのため、室温において高いＨｃＪを有し、かつ高温においても高いＨｃＪを有するＲ−Ｔ−Ｂ系焼結磁石が求められている。However, the conventional RTB -based sintered magnet has a problem that the coercive force H cJ (hereinafter, may be simply referred to as "H cJ ") decreases at a high temperature and irreversible thermal demagnetization occurs. is there. When an RTB -based sintered magnet is used in a motor for an electric vehicle, HcJ may decrease due to use at a high temperature, and stable operation of the motor may not be obtained. Therefore, there is a demand for RTB -based sintered magnets having high H cJ at room temperature and high H cJ even at high temperatures.

従来、室温におけるＨｃＪ向上のために、Ｒ−Ｔ−Ｂ系焼結磁石に重希土類元素ＲＨ（主としてＤｙ）を添加していたが、残留磁束密度Ｂｒ（以下、単に「Ｂｒ」と記載する場合がある）が低下するという問題があった。さらに、Ｄｙは、産出地が限定されている等の理由から、供給が不安定であり、また価格が大きく変動することがあるなどの問題を有している。そのため、Ｄｙなどの重希土類元素ＲＨをできるだけ使用せずにＲ−Ｔ−Ｂ系焼結磁石のＨｃＪを向上させる技術が求められている。Conventionally, a heavy rare earth element RH (mainly Dy) has been added to an RTB-based sintered magnet in order to improve HcJ at room temperature, but the residual magnetic flux density Br (hereinafter, simply referred to as “ Br ”). There was a problem that (may be described) decreased. Further, Dy has a problem that the supply is unstable and the price may fluctuate greatly because the production area is limited. Therefore, there is a demand for a technique for improving HcJ of RTB -based sintered magnets without using heavy rare earth elements RH such as Dy as much as possible.

このような技術として、例えば特許文献１は、通常のＲ−Ｔ−Ｂ系合金よりもＢ量を低くするとともに、Ａｌ、ＧａおよびＣｕのうちから選ばれる１種以上である金属元素Ｍを含有させることによりＲ２Ｔ１７相を生成させ、該Ｒ２Ｔ１７相を原料として生成させた遷移金属リッチ相（Ｒ−Ｔ−Ｇａ相）の体積率を充分に確保することにより、Ｄｙの含有量を抑制しつつ、保磁力の高いＲ−Ｔ−Ｂ系焼結磁石が得られることを開示している。As such a technique, for example, Patent Document 1 contains a metal element M which is one or more selected from Al, Ga and Cu while lowering the amount of B as compared with a normal RTB-based alloy. By allowing the R 2 T 17 phase to be generated, and by ensuring a sufficient volume ratio of the transition metal rich phase (RT-Ga phase) generated from the R 2 T 17 phase as a raw material, the content of Dy is contained. It is disclosed that an RTB-based sintered magnet having a high coercive force can be obtained while suppressing the amount.

国際公開第２０１３／００８７５６号公報International Publication No. 2013/0087756

しかし、特許文献１に記載されるＲ−Ｔ−Ｂ系焼結磁石はＨｃＪが向上しているものの、近年の要求を満足するには不十分である。However, although the RTB -based sintered magnet described in Patent Document 1 has improved HcJ , it is insufficient to satisfy recent demands.

そこで本発明の実施形態は、高い保磁力ＨｃＪを有するＲ−Ｔ−Ｂ系焼結磁石の製造方法を提供することを目的とする。Therefore, it is an object of the present invention to provide a method for manufacturing an RTB -based sintered magnet having a high coercive force HcJ .

本発明の態様１は、Ｒ：２８．５〜３３．０質量％（Ｒは希土類元素のうち少なくとも１種であり、ＮｄおよびＰｒの少なくとも１種を含む）、Ｂ：０．８５０〜０．９１０質量％、Ｇａ：０．２〜０．７質量％、Ｃｕ：０．０５〜０．５０質量％、Ａｌ：０．０５〜０．５０質量％、を含有し、残部がＴ（ＴはＦｅとＣｏであり、Ｔの９０質量％以上がＦｅである）および不可避的不純物であり、下記式（１）を満足するＲ−Ｔ−Ｂ系焼結磁石の製造方法であって、

１４［Ｂ］／１０．８＜［Ｔ］／５５．８５ （１）
（［Ｂ］は質量％で示すＢの含有量であり、［Ｔ］は質量％で示すＴの含有量である）

粒径Ｄ５０および粒径Ｄ９９が下記式（２）および（３）を満足する合金粉末を準備する工程と、前記合金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、前記焼結体に熱処理を施す熱処理工程と、を含む、Ｒ−Ｔ−Ｂ系焼結磁石の製造方法である。

３．８μｍ≦Ｄ５０≦５．５μｍ （２）
Ｄ９９≦１０μｍ （３）Aspect 1 of the present invention is R: 28.5 to 33.0% by mass (R is at least one of rare earth elements and includes at least one of Nd and Pr), B: 0.850 to 0. It contains 910% by mass, Ga: 0.2 to 0.7% by mass, Cu: 0.05 to 0.50% by mass, Al: 0.05 to 0.50% by mass, and the balance is T (T is Fe and Co, and 90% by mass or more of T is Fe) and unavoidable impurities, which is a method for producing an RTB-based sintered magnet satisfying the following formula (1).

14 [B] /10.8 <[T] /55.85 (1)
([B] is the content of B indicated by mass%, and [T] is the content of T indicated by mass%)

A step of preparing an alloy powder in which the particle diameter D 50 and the particle diameter D 99 satisfy the following formulas (2) and (3), a molding step of molding the alloy powder to obtain a molded body, and firing of the molded body. This is a method for manufacturing an RTB-based sintered magnet, which includes a sintering step of connecting to obtain a sintered body and a heat treatment step of applying a heat treatment to the sintered body.

3.8 μm ≤ D 50 ≤ 5.5 μm (2)
D 99 ≤ 10 μm (3)

本発明の態様２は、前記Ｒ−Ｔ−Ｂ系焼結磁石におけるＢが０．８７０〜０．９１０質量％である、態様１に記載のＲ−Ｔ−Ｂ系焼結磁石の製造方法である Aspect 2 of the present invention is the method for manufacturing an RTB-based sintered magnet according to the first aspect, wherein B in the RTB-based sintered magnet is 0.870 to 0.910% by mass. is there

本発明の態様３は、前記粒径Ｄ５０および粒径Ｄ９９がさらに下記式（４）および（５）を満足する、態様１又は２に記載のＲ−Ｔ−Ｂ系焼結磁石の製造方法である。
３．８μｍ≦Ｄ５０≦４．５μｍ （４）
Ｄ９９≦９μｍ （５）Aspect 3 of the present invention is the production of the RTB-based sintered magnet according to aspect 1 or 2, wherein the particle diameters D 50 and D 99 further satisfy the following formulas (4) and (5). The method.
3.8 μm ≤ D 50 ≤ 4.5 μm (4)
D 99 ≤ 9 μm (5)

本発明の実施形態によれば、高い保磁力ＨｃＪを有するＲ−Ｔ−Ｂ系焼結磁石を製造できる方法を提供することができる。According to the embodiment of the present invention, it is possible to provide a method capable of producing an RTB -based sintered magnet having a high coercive force HcJ .

図１は、実施例における、保磁力の向上幅ΔＨｃＪとＢ量との関係を表す図である。FIG. 1 is a diagram showing the relationship between the improvement width ΔH cJ of the coercive force and the amount of B in the embodiment.

以下に示す実施形態は、本発明の技術思想を具体化するためのＲ−Ｔ−Ｂ系焼結磁石の製造方法を例示するものであって、本発明を以下に限定するものではない。 The embodiments shown below exemplify a method for manufacturing an RTB-based sintered magnet for embodying the technical idea of the present invention, and the present invention is not limited to the following.

本発明者らは鋭意検討した結果、本発明の実施形態に記載するような特定の組成範囲、特に極めて狭い特定範囲のＢ含有量を有するＲ−Ｔ−Ｂ系焼結磁石の製造において、分級機等を用いて比較的大きな粒径を有する微粉末を取り除くことによって、合金粉末の粒度分布を調整することで、最終的に得られるＲ−Ｔ−Ｂ系焼結磁石のＨｃＪを大幅に上昇できることを見出した。As a result of diligent studies, the present inventors have classified the RTB-based sintered magnets having a specific composition range as described in the embodiment of the present invention, particularly a very narrow specific range of B content. By adjusting the particle size distribution of the alloy powder by removing the fine powder having a relatively large particle size using a machine or the like, the HcJ of the RTB -based sintered magnet finally obtained can be significantly increased. I found that I could rise.

従来のＲ−Ｔ−Ｂ系焼結磁石の製造においても比較的大きな粒径を有する微粉末を取り除くことは行われてきた。しかし、後述する実施例に示す通り、本発明の特定の組成範囲外では最終的に得られるＲ−Ｔ−Ｂ系焼結磁石のＨｃＪの向上幅が小さい。さらに比較的大きな粒径を有する微粉末を取り除くためには粉砕時間を長くしなければならず、粉砕能率が低下し、その結果、量産効率の悪化を招く。すなわち、従来は量産効率の悪化を招くにしてはＨｃＪの向上幅が小さすぎるため、実際の量産では積極的に行われることは無かった。Even in the production of conventional RTB-based sintered magnets, it has been practiced to remove fine powder having a relatively large particle size. However, as shown in Examples described later, the improvement range of HcJ of the RTB -based sintered magnet finally obtained is small outside the specific composition range of the present invention. Further, in order to remove the fine powder having a relatively large particle size, the crushing time must be lengthened, and the crushing efficiency is lowered, resulting in deterioration of mass production efficiency. That is, in the past, the improvement range of H cJ was too small to cause deterioration of mass production efficiency, so that it was not positively performed in actual mass production.

しかし、本発明者らは、後述するように、本発明の実施形態の特定の組成範囲（特にＢ含有量が０．８５０〜０．９１０質量％）であるＲ−Ｔ−Ｂ系焼結磁石の製造において、平均粒径Ｄ５０が３．８μｍ以上５．５μｍ以下、かつＤ９９が１０μｍ以下（好ましくは、平均粒径Ｄ５０が３．８μｍ以上４．５μｍ以下、かつＤ９９が９μｍ以下）となるように原料合金粉末を調整し、このような合金粉末を成形、焼結および熱処理することにより得られたＲ−Ｔ−Ｂ系焼結磁石は、粉砕時間が長くなることによる量産効率の悪化を招いたとしても積極的に行うことができるほど、大幅にＨｃＪが向上することを見出し、本発明に至ったものである。
以下に本発明の実施形態に係る製造方法について詳述する。However, as will be described later, the present inventors have an RTB-based sintered magnet having a specific composition range (particularly, a B content of 0.850 to 0.910% by mass) according to an embodiment of the present invention. The average particle size D 50 is 3.8 μm or more and 5.5 μm or less, and D 99 is 10 μm or less (preferably, the average particle size D 50 is 3.8 μm or more and 4.5 μm or less, and D 99 is 9 μm or less. ), And the RTB-based sintered magnet obtained by molding, sintering, and heat-treating such alloy powder has mass production efficiency due to a long crushing time. It was found that the HcJ is significantly improved so that it can be positively carried out even if it causes the deterioration of the above, and the present invention has been reached.
The manufacturing method according to the embodiment of the present invention will be described in detail below.

［Ｒ−Ｔ−Ｂ系焼結磁石］
まず、本発明の実施形態に係る製造方法により得られるＲ−Ｔ−Ｂ系焼結磁石について説明する。[RTB-based sintered magnet]
First, the RTB-based sintered magnet obtained by the manufacturing method according to the embodiment of the present invention will be described.

［Ｒ−Ｔ−Ｂ系焼結磁石の組成］
本実施形態に係るＲ−Ｔ−Ｂ系焼結磁石の組成は、
Ｒ：２８．５〜３３．０質量％（Ｒは希土類元素のうち少なくとも１種であり、ＮｄおよびＰｒの少なくとも１種を含む）、
Ｂ：０．８５０〜０．９１０質量％、
Ｇａ：０．２〜０．７質量％、
Ｃｕ：０．０５〜０．５０質量％、
Ａｌ：０．０５〜０．５０質量％、を含有し、
残部がＴ（ＴはＦｅとＣｏであり、Ｔの９０質量％以上がＦｅである）および不可避的不純物であり、下記式（１）を満足する。

１４［Ｂ］／１０．８＜［Ｔ］／５５．８５ （１）
（［Ｂ］は質量％で示すＢの含有量であり、［Ｔ］は質量％で示すＴの含有量である。）[Composition of RTB-based sintered magnet]
The composition of the RTB-based sintered magnet according to this embodiment is
R: 28.5 to 33.0% by mass (R is at least one rare earth element and contains at least one of Nd and Pr),
B: 0.850 to 0.910% by mass,
Ga: 0.2 to 0.7% by mass,
Cu: 0.05 to 0.50% by mass,
Al: contains 0.05 to 0.50% by mass,
The balance is T (T is Fe and Co, and 90% by mass or more of T is Fe) and unavoidable impurities, satisfying the following formula (1).

14 [B] /10.8 <[T] /55.85 (1)
([B] is the content of B represented by mass%, and [T] is the content of T represented by mass%.)

上記組成により、一般的なＲ−Ｔ−Ｂ系焼結磁石よりもＢ量を少なくするとともに、Ｇａ等を含有させているので、二粒子粒界にＲ−Ｔ−Ｇａ相が生成して、高いＨｃＪを得ることができる。ここで、Ｒ−Ｔ−Ｇａ相とは、代表的にはＮｄ６Ｆｅ１３Ｇａ化合物である。Ｒ６Ｔ１３Ｇａ化合物は、Ｌａ６Ｃｏ１１Ｇａ３型結晶構造を有する。また、Ｒ６Ｔ１３Ｇａ化合物は、その状態によっては、Ｒ６Ｔ１３−δＧａ１＋δ化合物（δは典型的には２以下）になっている場合がある。例えば、Ｒ−Ｔ−Ｂ系焼結磁石中にＣｕ、Ａｌが比較的多く含有される場合、Ｒ６Ｔ１３−δ（Ｇａ１−ｘ−ｙＣｕｘＡｌｙ）１＋δになっている場合がある。
以下に、各組成について詳述する。With the above composition, the amount of B is smaller than that of a general RT-B-based sintered magnet, and Ga and the like are contained, so that an RT-Ga phase is generated at the two-particle boundary. High H cJ can be obtained. Here, the RT-Ga phase is typically an Nd 6 Fe 13 Ga compound. The R 6 T 13 Ga compound has a La 6 Co 11 Ga type 3 crystal structure. Further, the R 6 T 13 Ga compound may be an R 6 T 13-δ Ga 1 + δ compound (δ is typically 2 or less) depending on the state. For example, when the R-TB-based sintered magnet contains a relatively large amount of Cu and Al, it may be R 6 T 13-δ (Ga 1-xy Cu x Al y ) 1 + δ. is there.
Each composition will be described in detail below.

（Ｒ：２８．５〜３３．０質量％）
Ｒは、希土類元素のうち少なくとも１種であり、ＮｄおよびＰｒの少なくとも１種を含む。Ｒの含有量は、２８．５〜３３．０質量％である。Ｒが２８．５質量％未満であると焼結時の緻密化が困難となるおそれがあり、３３．０質量％を超えると主相比率が低下して高いＢｒを得られないおそれがある。Ｒの含有量は、好ましくは２９．５〜３２．５質量％である。Ｒがこのような範囲であれば、より高いＢｒを得ることができる。(R: 28.5 to 33.0% by mass)
R is at least one of the rare earth elements and contains at least one of Nd and Pr. The content of R is 28.5 to 33.0% by mass. R is may become difficult to densification during sintering is less than 28.5% by mass may main phase proportion exceeds 33.0% by weight can not be obtained a high B r drops .. The content of R is preferably 29.5 to 32.5% by mass. If R is in such a range, a higher Br can be obtained.

（Ｂ：０．８５０〜０．９１０質量％）
Ｂの含有量は、０．８５０〜０．９１０質量％である。本発明の実施形態では特にＢの含有量がこのような狭い範囲であれば、後述する合金粉末を得る工程において、合金粉末の粒度Ｄ５０およびＤ９９が本発明の実施形態で規定する所定の範囲になるように管理することで、最終的に得られるＲ−Ｔ−Ｂ系焼結磁石のＨｃＪを大幅に向上することができる。Ｂの含有量が０．８５０質量％未満及び０．９１０質量％を超えると、高いＨｃＪ向上効果を得ることができない。好ましくは、Ｂの含有量は、０．８７０〜０．９１０質量％である。より高いＨｃＪ向上効果が得られる。(B: 0.850 to 0.910% by mass)
The content of B is 0.850 to 0.910% by mass. In the embodiment of the present invention, particularly when the content of B is in such a narrow range, the particle sizes D 50 and D 99 of the alloy powder are predetermined as defined in the embodiment of the present invention in the step of obtaining the alloy powder described later. By managing the range so as to be within the range, the HcJ of the finally obtained RTB -based sintered magnet can be significantly improved. If the content of B is less than 0.850% by mass and exceeds 0.910% by mass, a high HcJ improving effect cannot be obtained. Preferably, the content of B is 0.870 to 0.910% by mass. A higher H cJ improving effect can be obtained.

さらに、Ｂの含有量は下記式（１）を満たす。

１４［Ｂ］／１０．８＜［Ｔ］／５５．８５ （１）

式（１）を満足することにより、Ｂの含有量が一般的なＲ−Ｔ−Ｂ系焼結磁石よりも少なくなる。一般的なＲ−Ｔ−Ｂ系焼結磁石は、主相であるＲ２Ｔ１４Ｂ相以外に軟磁性相であるＲ２Ｔ１７相が生成しないように、［Ｔ］／５５．８５（Ｆｅの原子量）は１４［Ｂ］／１０．８（Ｂの原子量）よりも少ない組成となっている（［Ｔ］は、質量％で示すＴの含有量である）。本発明の実施形態のＲ−Ｔ−Ｂ系焼結磁石は、一般的なＲ−Ｔ−Ｂ系焼結磁石と異なり、［Ｔ］／５５．８５が１４［Ｂ］／１０．８よりも多くなるように式（１）で規定している。なお、本発明の実施形態のＲ−Ｔ−Ｂ系焼結磁石におけるＴの主成分はＦｅであるため、Ｆｅの原子量を用いた。Further, the content of B satisfies the following formula (1).

14 [B] /10.8 <[T] /55.85 (1)

By satisfying the formula (1), the content of B becomes smaller than that of a general RTB-based sintered magnet. Typical R-T-B based sintered magnet, the main phase R 2 T 14 in addition to B phase as R 2 T 17 phase is not generated corresponding to the soft magnetic phase, [T] /55.85 ( The atomic weight of Fe) is less than 14 [B] / 10.8 (atomic weight of B) ([T] is the content of T in mass%). The RTB-based sintered magnet of the embodiment of the present invention is different from a general RTB-based sintered magnet, and [T] /55.85 is higher than 14 [B] /10.8. It is specified by the formula (1) so that the number increases. Since the main component of T in the RTB-based sintered magnet of the embodiment of the present invention is Fe, the atomic weight of Fe was used.

（Ｇａ：０．２〜０．７質量％）
Ｇａの含有量は、０．２〜０．７質量％である。Ｇａが０．２質量％未満であると、Ｒ−Ｔ−Ｇａ相の生成量が少なすぎて、Ｒ２Ｔ１７相を消失させることができず、高いＨｃＪを得ることができないおそれがあり、０．７質量％を超えると不要なＧａが存在することになり、主相比率が低下してＢｒが低下するおそれがある。(Ga: 0.2 to 0.7% by mass)
The content of Ga is 0.2 to 0.7% by mass. If Ga is less than 0.2% by mass, the amount of R-T-Ga phase produced is too small, and the R 2 T 17 phase cannot be eliminated, and a high H cJ may not be obtained. It will be present unnecessary Ga exceeds 0.7 weight%, there is a possibility that B r decreases to decrease the main phase proportion.

（Ｃｕ：０．０５〜０．５０質量％）
Ｃｕの含有量は、０．０５〜０．５０質量％である。Ｃｕが０．０５質量％未満であると高いＨｃＪを得ることができないおそれがあり、０．５０質量％を超えると焼結性が悪化して高いＨｃＪが得られないおそれがある。(Cu: 0.05 to 0.50% by mass)
The content of Cu is 0.05 to 0.50% by mass. If Cu is less than 0.05% by mass, high H cJ may not be obtained, and if it exceeds 0.50% by mass, sinterability may deteriorate and high H cJ may not be obtained.

（Ａｌ：０．０５〜０．５０質量％）
Ａｌの含有量は、０．０５〜０．５０質量％である。Ａｌを含有することによりＨｃＪを向上させることができる。Ａｌは通常、製造工程で不可避的不純物として０．０５質量％以上含有されるが、不可避的不純物で含有される量と意図的に添加した量の合計で０．５質量％以下含有してもよい。(Al: 0.05 to 0.50% by mass)
The Al content is 0.05 to 0.50% by mass. HcJ can be improved by containing Al. Al is usually contained in an amount of 0.05% by mass or more as an unavoidable impurity in the manufacturing process, but even if it is contained in an amount of 0.5% by mass or less in total of the amount contained in the unavoidable impurity and the amount intentionally added. Good.

（残部：Ｔおよび不可避的不純物）
残部はＴおよび不可避的不純物である。ここでＴはＦｅとＣｏであり、Ｔの９０質量％以上がＦｅである。Ｃｏを含有することにより耐食性を向上させることができるが、Ｃｏの置換量がＦｅの１０質量％を超えると、高いＢｒが得られないおそれがある。
さらに、本発明の実施形態のＲ−Ｔ−Ｂ系焼結磁石は、ジジム合金（Ｎｄ−Ｐｒ）、電解鉄、フェロボロンなどに通常含有される不可避的不純物としてＣｒ、Ｍｎ、Ｓｉ、Ｌａ、Ｃｅ、Ｓｍ、Ｃａ、Ｍｇなどを含有することができる。さらに、製造工程中の不可避的不純物として、Ｏ（酸素）、Ｎ（窒素）およびＣ（炭素）などを例示できる。また、少量（０．１質量％程度）のＶ、Ｎｉ、Ｍｏ、Ｈｆ、Ｔａ、Ｗ、Ｎｂ、Ｚｒなどを含有してもよい。(Remaining: T and unavoidable impurities)
The rest are T and unavoidable impurities. Here, T is Fe and Co, and 90% by mass or more of T is Fe. Corrosion resistance can be improved by containing Co, but if the substitution amount of Co exceeds 10% by mass of Fe, high Br may not be obtained.
Further, the RTB-based sintered magnet according to the embodiment of the present invention has Cr, Mn, Si, La, Ce as unavoidable impurities usually contained in didymium alloy (Nd-Pr), electrolytic iron, ferrobolon and the like. , Sm, Ca, Mg and the like can be contained. Further, O (oxygen), N (nitrogen), C (carbon) and the like can be exemplified as unavoidable impurities in the manufacturing process. Further, a small amount (about 0.1% by mass) of V, Ni, Mo, Hf, Ta, W, Nb, Zr and the like may be contained.

以下に、本発明の実施形態に係るＲ−Ｔ−Ｂ系焼結磁石の製造方法の詳細を説明する。 The details of the method for manufacturing the RTB-based sintered magnet according to the embodiment of the present invention will be described below.

［Ｒ−Ｔ−Ｂ系焼結磁石の製造方法］
上述した組成を有するＲ−Ｔ−Ｂ系焼結磁石の製造方法を説明する。Ｒ−Ｔ−Ｂ系焼結磁石の製造方法は、合金粉末を得る工程、成形工程、焼結工程、熱処理工程を有する。
以下、各工程について説明する。[Manufacturing method of RTB-based sintered magnet]
A method for manufacturing an RTB-based sintered magnet having the above-mentioned composition will be described. The method for producing an RTB-based sintered magnet includes a step of obtaining an alloy powder, a molding step, a sintering step, and a heat treatment step.
Hereinafter, each step will be described.

（１）合金粉末を得る工程
この工程において、上述したＲ−Ｔ−Ｂ系焼結磁石と同じ組成を有し、粒径Ｄ５０が３．８μｍ以上５．５μｍ以下であり、かつ粒径Ｄ９９が１０μｍ以下の合金粉末を得る。粒径Ｄ５０およびＤ９９がこのような範囲であり、また、本実施形態に係るＲ−Ｔ−Ｂ系焼結磁石の組成となるように調整した合金粉末を用いることにより、最終的に得られるＲ−Ｔ−Ｂ系焼結磁石は、高い保磁力ＨｃＪを有することができる。(1) Step of obtaining alloy powder In this step, it has the same composition as the above-mentioned RTB-based sintered magnet, the particle size D 50 is 3.8 μm or more and 5.5 μm or less, and the particle size D An alloy powder having 99 of 10 μm or less is obtained. By using an alloy powder adjusted so that the particle sizes D 50 and D 99 are in such a range and the composition of the RTB-based sintered magnet according to the present embodiment is obtained, it is finally obtained. The RTB -based sintered magnet to be used can have a high coercive force HcJ .

このような合金粉末は、例えば次のように得ることができる。
上述したＲ−Ｔ−Ｂ系焼結磁石の組成となるように各元素の金属または合金（溶解原料）を準備し、ストリップキャスティング法等によりフレーク状の原料合金を作製する。次に、前記フレーク状の原料合金から合金粉末を作製する。得られたフレーク状の原料合金を水素粉砕し、例えば１．０ｍｍ以下の粗粉砕粉を得る。次に、粗粉砕粉を不活性ガス中でジェットミル等により微粉砕し、分級機を用いて、粒径の大きな微粉砕粉を取り除き、粒径Ｄ５０が３．８μｍ以上５．５μｍ以下であり、かつ粒径Ｄ９９が１０μｍ以下の微粉砕粉（合金粉末）を得る。このような粒度分布を有する合金粉末を用いて上述した組成を有するＲ−Ｔ−Ｂ系焼結磁石を製造することにより、高い保磁力ＨｃＪを有するＲ−Ｔ−Ｂ系焼結磁石を得ることができる。合金粉末は、粒径Ｄ５０が３．８μｍ以上４．５μｍ以下であり、かつＤ９９が９μｍ以下であることがより好ましい。このような範囲であれば、最終的に得られるＲ−Ｔ−Ｂ系焼結磁石のＨｃＪをより向上することができる。Such an alloy powder can be obtained, for example, as follows.
A metal or alloy (dissolved raw material) of each element is prepared so as to have the composition of the RTB-based sintered magnet described above, and a flake-shaped raw material alloy is produced by a strip casting method or the like. Next, an alloy powder is produced from the flake-shaped raw material alloy. The obtained flake-shaped raw material alloy is hydrogen-pulverized to obtain, for example, a coarsely pulverized powder of 1.0 mm or less. Next, the coarsely pulverized powder is finely pulverized in an inert gas by a jet mill or the like, and the finely pulverized powder having a large particle size is removed by using a classifier, and the particle size D 50 is 3.8 μm or more and 5.5 μm or less. A finely pulverized powder (alloy powder) having a particle size D 99 of 10 μm or less is obtained. By producing an RT-B-based sintered magnet having the above-mentioned composition using an alloy powder having such a particle size distribution, an RT-B-based sintered magnet having a high coercive force HcJ can be obtained. be able to. It is more preferable that the alloy powder has a particle size D 50 of 3.8 μm or more and 4.5 μm or less and a D 99 of 9 μm or less. Within such a range, the HcJ of the finally obtained RTB -based sintered magnet can be further improved.

合金粉末は、１種類の合金粉末（単合金粉末）を用いてもよいし、２種類以上の合金粉末を混合することにより合金粉末（混合合金粉末）を得る、いわゆる２合金法を用いてもよく、公知の方法などを用いて本発明の実施形態の組成となるように合金粉末を作製すればよい。なお、ジェットミル粉砕前の粗粉砕粉、ジェットミル粉砕中およびジェットミル粉砕後の合金粉末に助剤として公知の潤滑剤を添加してもよい。 As the alloy powder, one kind of alloy powder (single alloy powder) may be used, or an alloy powder (mixed alloy powder) may be obtained by mixing two or more kinds of alloy powders, or a so-called two-alloy method may be used. Often, an alloy powder may be prepared using a known method or the like so as to have the composition of the embodiment of the present invention. A known lubricant may be added as an auxiliary agent to the coarsely pulverized powder before jet mill pulverization, and the alloy powder during and after jet mill pulverization.

上述のように、本実施形態に係る合金粉末は特定の範囲の粒径Ｄ５０およびＤ９９を有するが、粒径Ｄ５０およびＤ９９は、気流分散式レーザー回折法（ＪＩＳ Ｚ ８８２５：２０１３年改訂版に準拠する）により測定することができる。すなわち、本明細書において、Ｄ５０は、小粒径側からの積算粒度分布（体積基準）が５０％となる粒径（メジアン径）を意味し、Ｄ９９は、小粒径側からの積算粒度分布（体積基準）が９９％となる粒径を意味する。
なお本発明の実施形態におけるＤ５０とＤ９９は、Ｓｙｍｐａｔｅｃ社製の粒度分布測定装置「ＨＥＬＯＳ＆ＲＯＤＯＳ」において
分散圧：４ｂａｒ
測定レンジ：Ｒ２
計算モード：ＨＲＬＤ
の条件にて測定されたＤ５０とＤ９９のことを示す。As described above, the alloy powder according to this embodiment has particle sizes D 50 and D 99 in a specific range, but the particle sizes D 50 and D 99 are determined by the air flow dispersion laser diffraction method (JIS Z 8825: 2013). It can be measured by (according to the revised version). That is, in the present specification, D 50 means a particle size (median diameter) at which the integrated particle size distribution (volume basis) from the small particle size side is 50%, and D 99 means an integrated particle size distribution from the small particle size side. It means a particle size having a particle size distribution (volume basis) of 99%.
Note that D 50 and D 99 in the embodiment of the present invention have a dispersion pressure of 4 bar in the particle size distribution measuring device "HELOS &RODOS" manufactured by Symboltec.
Measurement range: R2
Calculation mode: HRLD
It shows D 50 and D 99 measured under the condition of.

（２）成形工程
得られた合金粉末を用いて磁界中成形を行い、成形体を得る。磁界中成形は、金型のキャビティー内に乾燥した合金粉末を挿入し、磁界を印加しながら成形する乾式成形法、金型のキャビティー内に該合金粉末を分散させたスラリーを注入し、スラリーの分散媒を排出しながら成形する湿式成形法を含む既知の任意の磁界中成形方法を用いてよい。(2) Molding step Molding is performed in a magnetic field using the obtained alloy powder to obtain a molded product. Molding in a magnetic field is a dry molding method in which a dry alloy powder is inserted into a cavity of a mold and molded while applying a magnetic field, and a slurry in which the alloy powder is dispersed is injected into the cavity of the mold. Any known in-magnetic field molding method may be used, including a wet molding method of molding while discharging the dispersion medium of the slurry.

（３）焼結工程
成形体を焼結することにより焼結体（焼結磁石）を得る。成形体の焼結は既知の方法を用いることができる。なお、焼結時の雰囲気による酸化を防止するために、焼結は、真空雰囲気中または雰囲気ガス中で行うことが好ましい。雰囲気ガスは、ヘリウム、アルゴンなどの不活性ガスを用いることが好ましい。(3) Sintering step A sintered body (sintered magnet) is obtained by sintering the molded body. A known method can be used for sintering the molded product. In addition, in order to prevent oxidation due to the atmosphere at the time of sintering, it is preferable to perform sintering in a vacuum atmosphere or an atmospheric gas. As the atmospheric gas, it is preferable to use an inert gas such as helium or argon.

（４）熱処理工程
得られた焼結磁石に対し、磁気特性を向上させることを目的とした熱処理を行うことが好ましい。熱処理温度、熱処理時間などは既知の条件を用いることができる。例えば、比較的低い温度（４００℃以上６００℃以下）のみでの熱処理（一段熱処理）をしてもよく、あるいは比較的高い温度（７００℃以上焼結温度以下（例えば１０５０℃以下））で熱処理を行った後比較的低い温度（４００℃以上６００℃以下）で熱処理（二段熱処理）をしてもよい。好ましい条件は、７３０℃以上１０２０℃以下で５分から５００分程度の熱処理を施し、冷却後（室温まで冷却後、または４４０℃以上５５０℃以下まで冷却後）、さらに４４０℃以上５５０℃以下で５分から５００分程度熱処理をすることが挙げられる。熱処理雰囲気は、真空雰囲気あるいは不活性ガス（ヘリウムやアルゴンなど）で行うことが好ましい。(4) Heat Treatment Step It is preferable to heat-treat the obtained sintered magnet for the purpose of improving the magnetic characteristics. Known conditions can be used for the heat treatment temperature, heat treatment time, and the like. For example, heat treatment (one-step heat treatment) may be performed only at a relatively low temperature (400 ° C. or higher and 600 ° C. or lower), or heat treatment may be performed at a relatively high temperature (700 ° C. or higher and sintering temperature or lower (for example, 1050 ° C. or lower)). After that, heat treatment (two-stage heat treatment) may be performed at a relatively low temperature (400 ° C. or higher and 600 ° C. or lower). Preferred conditions are heat treatment at 730 ° C. or higher and 1020 ° C. or lower for about 5 to 500 minutes, after cooling (after cooling to room temperature or cooling to 440 ° C. or higher and 550 ° C. or lower), and further at 440 ° C. or higher and 550 ° C. or lower. Heat treatment may be performed for about 1 to 500 minutes. The heat treatment atmosphere is preferably a vacuum atmosphere or an inert gas (helium, argon, etc.).

最終的な製品形状にするなどの目的で、得られた焼結磁石に研削などの機械加工を施してもよい。その場合、熱処理は機械加工前でも機械加工後でもよい。さらに、得られた焼結磁石に、表面処理を施してもよい。表面処理は、既知の表面処理であってもよく、例えばＡｌ蒸着や電気Ｎｉめっきや樹脂塗料などの表面処理を行うことができる。 The obtained sintered magnet may be machined by grinding or the like for the purpose of forming the final product shape. In that case, the heat treatment may be performed before or after machining. Further, the obtained sintered magnet may be surface-treated. The surface treatment may be a known surface treatment, and for example, surface treatment such as Al vapor deposition, nickel plating, or resin coating can be performed.

本発明を実施例によりさらに詳細に説明するが、本発明はそれらに限定されるものではない。 The present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

・実施例１
表１の試料Ｎｏ．１〜２７に示すＲ−Ｔ−Ｂ系焼結磁石の組成となるように各元素を秤量し、ストリップキャスト法により合金を作製した。得られた各合金を水素粉砕法により粗粉砕し粗粉砕粉を得た。前記粗粉砕粉を、以下に説明するＡ〜Ｃのいずれかの条件で、それぞれジェットミルにより微粉砕を行った（但し、条件Ｃで微粉砕を行ったのは試料Ｎｏ．１３のみ）。・ Example 1
Sample No. in Table 1 Each element was weighed so as to have the composition of the RTB-based sintered magnet shown in 1-27, and an alloy was prepared by a strip casting method. Each of the obtained alloys was coarsely pulverized by a hydrogen pulverization method to obtain a coarsely pulverized powder. The coarsely pulverized powder was finely pulverized by a jet mill under any of the conditions A to C described below (however, only sample No. 13 was pulverized under condition C).

（条件Ａ）
条件Ａは、ジェットミルへの原料供給量を２００ｇ／分、分級ロータ回転数を４５００ｒｐｍにして微粉砕を行った。粉砕時間は約１０分であった。条件Ａは通常の粉砕条件であり、狙い値は粒径Ｄ５０：４μｍ、粒径Ｄ９９：１２μｍである。尚、前記Ｄ５０及び前記Ｄ９９は、それぞれ、気流分散法によるレーザー回折法で得られる粒度分布において、小粒径側からの積算粒度分布（体積基準）が５０％となる粒径及び小粒径側からの積算粒度分布（体積基準）が９９％となる粒径である。また、Ｄ５０及びＤ９９は、Ｓｙｍｐａｔｅｃ社製の粒度分布測定装置「ＨＥＬＯＳ＆ＲＯＤＯＳ」を用いて、分散圧：４ｂａｒ、測定レンジ：Ｒ２、計算モード：ＨＲＬＤの条件にて測定した。(Condition A)
Under condition A, the amount of raw material supplied to the jet mill was 200 g / min, and the number of revolutions of the classification rotor was 4500 rpm for fine pulverization. The crushing time was about 10 minutes. Condition A is a normal pulverization condition, and the target values are particle size D 50 : 4 μm and particle size D 99 : 12 μm. The D 50 and the D 99 have a particle size and a small particle size distribution in which the integrated particle size distribution (volume basis) from the small particle size side is 50% in the particle size distribution obtained by the laser diffraction method by the air flow dispersion method, respectively. The particle size is such that the integrated particle size distribution (volume basis) from the diameter side is 99%. Further, D 50 and D 99 were measured by using a particle size distribution measuring device “HELOS & RODOS” manufactured by Symbolec under the conditions of dispersion pressure: 4 bar, measurement range: R2, and calculation mode: HRLD.

（条件Ｂ）
条件Ｂは、ジェットミルへの原料供給量を５０ｇ／分、分級ロータ回転数を５５００ｒｐｍにして微粉砕を行った。粉砕時間は約４０分であった。条件Ｂは、本発明の実施形態の粒径（Ｄ５０及びＤ９９）を得るために行うものであり、狙い値は粒径Ｄ５０：４μｍ、粒径Ｄ９９：９．５μｍである。条件Ｃは、ジェットミルへの原料供給量を５０ｇ／分、分級ロータ回転数を６０００ｒｐｍにして微粉砕を行った。粉砕時間は約４０分であった。(Condition B)
In condition B, the amount of raw material supplied to the jet mill was set to 50 g / min, the classifying rotor rotation speed was set to 5500 rpm, and fine pulverization was performed. The crushing time was about 40 minutes. Condition B is performed to obtain the particle size (D 50 and D 99 ) of the embodiment of the present invention, and the target values are the particle size D 50 : 4 μm and the particle size D 99 : 9.5 μm. Under condition C, the amount of raw material supplied to the jet mill was 50 g / min, and the number of revolutions of the classification rotor was 6000 rpm for fine pulverization. The crushing time was about 40 minutes.

（条件Ｃ）
条件Ｃは、本発明の実施形態の好ましい粒径（Ｄ５０及びＤ９９）を得るために行うものであり、狙い値は粒径Ｄ５０：４μｍ、粒径Ｄ９９：８．５μｍである。(Condition C)
Condition C is performed in order to obtain preferable particle sizes (D 50 and D 99 ) of the embodiment of the present invention, and the target values are particle size D 50 : 4 μm and particle size D 99 : 8.5 μm.

各条件で微粉砕して得られた微粉砕粉の粒径（Ｄ５０及びＤ９９）の実測値を表２及び表３に示す。表２の「条件Ａ」には、試料Ｎｏ．１〜２７を条件Ａで微粉砕して得られた微粉砕粉の粒径の実測値が示されている。表２の「条件Ｂ」には、試料Ｎｏ．１〜２７を条件Ｂで微粉砕して得られた微粉砕粉の粒径の実測値が示されている。表３の「条件Ａ」には、試料Ｎｏ．１３を条件Ａで微粉砕して得られた粒径の実測値が示されている。表３の「条件Ｃ」には、試料Ｎｏ．１３を条件Ｃで微粉砕して得られた粒径の実測値が示されている。Tables 2 and 3 show the measured values of the particle sizes (D 50 and D 99 ) of the finely pulverized powder obtained by pulverizing under each condition. In "Condition A" in Table 2, the sample No. The measured values of the particle diameters of the finely pulverized powder obtained by finely pulverizing 1 to 27 under the condition A are shown. “Condition B” in Table 2 shows the sample No. The measured values of the particle diameters of the finely pulverized powder obtained by finely pulverizing 1 to 27 under the condition B are shown. “Condition A” in Table 3 shows the sample No. The actually measured value of the particle diameter obtained by finely pulverizing No. 13 under the condition A is shown. “Condition C” in Table 3 shows the sample No. The actually measured value of the particle diameter obtained by finely pulverizing No. 13 under the condition C is shown.

得られた微粉砕粉（合金粉末）に、潤滑剤としてステアリン酸亜鉛を微粉砕粉１００質量部に対して０．０５質量部添加、混合した後、磁界中で成形し、成形体を得た。なお、成形装置には、磁界印加方向と加圧方向とが直交する、いわゆる直角磁界成形装置（横磁界成形装置）を用いた。得られた成形体を、真空中で組成に応じて１０３０〜１０７０℃で４時間焼結し、Ｒ−Ｔ−Ｂ系焼結磁石を得た。焼結磁石の密度は７．５Ｍｇ／ｍ３以上であった。さらに焼結後のＲ−Ｔ−Ｂ系焼結磁石に対し、８００℃で２時間保持した後室温まで急冷し、次いで５００℃で２時間保持した後室温まで冷却する熱処理を施した。To the obtained finely pulverized powder (alloy powder), 0.05 part by mass of zinc stearate was added as a lubricant to 100 parts by mass of the finely pulverized powder, mixed, and then molded in a magnetic field to obtain a molded product. .. As the molding apparatus, a so-called right-angle magnetic field forming apparatus (transverse magnetic field forming apparatus) in which the magnetic field application direction and the pressurizing direction are orthogonal to each other was used. The obtained molded product was sintered in vacuum at 1030 to 1070 ° C. for 4 hours to obtain an RTB-based sintered magnet. The density of the sintered magnet was 7.5 Mg / m 3 or more. Further, the sintered RTB-based sintered magnet was subjected to a heat treatment of holding at 800 ° C. for 2 hours and then rapidly cooling to room temperature, then holding at 500 ° C. for 2 hours and then cooling to room temperature.

得られた焼結磁石の成分を求めるために、Ｎｄ、Ｐｒ、Ｔｂ、Ｂ、Ｃｏ、Ａｌ、Ｃｕ、Ｇａ、Ｎｂ、Ｚｒ、Ｆｅの含有量をＩＣＰ発光分光分析法により測定した。さらに、Ｏ（酸素量）はガス融解−赤外線吸収法、Ｎ（窒素量）はガス融解−熱伝導法、Ｃ（炭素量）は燃焼−赤外線吸収法、によるガス分析装置を使用して測定した。結果を表１に示す。 In order to determine the components of the obtained sintered magnet, the contents of Nd, Pr, Tb, B, Co, Al, Cu, Ga, Nb, Zr and Fe were measured by ICP emission spectroscopy. Furthermore, O (oxygen amount) was measured using a gas melting-infrared absorption method, N (nitrogen amount) was measured using a gas melting-heat conduction method, and C (carbon amount) was measured using a combustion-infrared absorption method. .. The results are shown in Table 1.

熱処理後の焼結磁石に機械加工を施し、縦７ｍｍ、横７ｍｍ、厚み７ｍｍの試料を作製し、Ｂ−Ｈトレーサによって各試料の特性（Ｂｒ及びＨｃＪ）を測定した。測定結果を表２及び表３に示す。
なお、表２および表３の備考欄に記載された「本発明例」とは、本発明の実施形態に規定する要件を満たす実施例であることを意味する。By machining the sintered magnet after the heat treatment, vertical 7 mm, transverse 7 mm, to prepare a sample having a thickness of 7 mm, were measured properties of each sample (B r and H cJ) by B-H tracer. The measurement results are shown in Tables 2 and 3.
The "example of the present invention" described in the remarks column of Tables 2 and 3 means that the example satisfies the requirements specified in the embodiment of the present invention.

表２の「条件Ａ」には、表１の試料Ｎｏ．１〜２７の組成を有する合金を条件Ａで微粉砕し、得られた微粉砕粉を焼結、熱処理して得られた焼結磁石の特性値が示されている。表２の「条件Ｂ」には、表１の試料Ｎｏ．１〜２７の組成を有する合金を条件Ｂで微粉砕し、得られた微粉砕粉を焼結、熱処理して得られた焼結磁石の特性値（Ｂｒ及びＨｃＪの値）が示されている。また、表２の「条件Ｂ−条件Ａ」には、微粉砕の条件を条件Ａから条件Ｂに変更したことによる焼結磁石のＨｃＪの向上幅（ΔＨｃＪ）を示されている。つまり、表２におけるΔＨｃＪは、微粉砕粉を条件Ａまたは条件Ｂで作製することにより得られたＲ−Ｔ−Ｂ系焼結磁石におけるＨｃＪの差（条件Ｂを用いて得られたＲ−Ｔ−Ｂ系焼結磁石のＨｃＪの値から条件Ａを用いて得られたＲ−Ｔ−Ｂ系焼結磁石のＨｃＪの値を引いたもの）である。“Condition A” in Table 2 includes the sample No. in Table 1. The characteristic values of the sintered magnet obtained by finely pulverizing an alloy having a composition of 1 to 27 under condition A, sintering the obtained finely pulverized powder, and heat-treating it are shown. “Condition B” in Table 2 includes the sample No. in Table 1. Alloy was milled in condition B the having a composition of 1 to 27, sintering the finely pulverized powder obtained, the characteristic values of the sintered magnet obtained by heat treatment (the value of B r and H cJ) is shown ing. Further, in “Condition B-Condition A” in Table 2, the improvement width (ΔH cJ ) of H cJ of the sintered magnet by changing the condition of pulverization from the condition A to the condition B is shown. That is, ΔH cJ in Table 2 is the difference in H cJ in the RTB -based sintered magnet obtained by producing the finely pulverized powder under condition A or condition B (R obtained by using condition B). minus the value of H cJ of R-T-B based sintered magnet obtained by using the condition a from the value of H cJ of -T-B based sintered magnet) is.

表３の「条件Ａ」には、表１の試料Ｎｏ．１３の組成を有する合金を条件Ａで微粉砕し、得られた微粉砕粉を焼結、熱処理して得られた焼結磁石の特性値が示されている。表３の「条件Ｃ」には、表１の試料Ｎｏ．１３の組成を有する合金を条件Ｃで微粉砕し、得られた微粉砕粉を焼結、熱処理して得られた焼結磁石の特性値が示されている。表３の「条件Ｃ−条件Ａ」には、微粉砕の条件を条件Ａから条件Ｃに変更したことによる焼結磁石のＨｃＪの向上幅（ΔＨｃＪ）が示されている。つまり、表３におけるΔＨｃＪは、微粉砕粉を条件Ａまたは条件Ｃで作製することにより得られたＲ−Ｔ−Ｂ系焼結磁石におけるＨｃＪの差（条件Ｃを用いて得られたＲ−Ｔ−Ｂ系焼結磁石のＨｃＪの値から条件Ａを用いて得られたＲ−Ｔ−Ｂ系焼結磁石のＨｃＪの値を引いたもの）である。“Condition A” in Table 3 includes the sample No. in Table 1. The characteristic values of the sintered magnet obtained by finely pulverizing the alloy having the composition of 13 under the condition A, sintering the obtained finely pulverized powder, and heat-treating it are shown. “Condition C” in Table 3 includes the sample No. in Table 1. The characteristic values of the sintered magnet obtained by finely pulverizing the alloy having the composition of 13 under the condition C, sintering the obtained finely pulverized powder, and heat-treating it are shown. “Condition C-Condition A” in Table 3 shows the improvement width (ΔH cJ ) of H cJ of the sintered magnet by changing the pulverization condition from the condition A to the condition C. That is, ΔH cJ in Table 3 is the difference in H cJ in the RTB -based sintered magnet obtained by producing the finely pulverized powder under condition A or C (R obtained by using condition C). minus the value of H cJ of R-T-B based sintered magnet obtained by using the condition a from the value of H cJ of -T-B based sintered magnet) is.

Figure 0006798546
Figure 0006798546

Figure 0006798546
Figure 0006798546

Figure 0006798546
Figure 0006798546

表２に示すように、試料Ｎｏ．１〜２７のいずれの焼結磁石も、使用する微粉砕粉（合金粉末）の粒径Ｄ５０及び粒径Ｄ９９を本発明の実施形態の粒径（条件Ｂで作製した微粉砕粉）にすることにより、通常の粒径（条件Ａで作製）の場合と比べて、Ｂｒの低下なしにＨｃＪが向上（ΔＨｃＪが０を超えている）している。しかし、本発明の実施形態の組成を満たしていない試料Ｎｏ．１５〜２６の比較例は、焼結磁石のＨｃＪの向上幅（ΔＨｃＪ）が３６〜５７ｋＡ／ｍと十分ではなかった。これ対し、本発明の実施形態の組成範囲（試料Ｎｏ．１〜１４及び２７）であると、ΔＨｃＪが８７〜１０１ｋＡ／ｍとなり、比較例の約１．５〜２．５倍と大幅に向上した。このように、本発明の実施形態の組成を満たすことにより、高いＢｒと高いＨｃＪが得られている。上述したように、条件Ａ（通常の粒度）から条件Ｂ（本発明の実施形態の粒度）にすることにより、粉砕時間が１０分から４０分と長くなる。よって、本発明の実施形態の組成を満たしていない場合はＨｃＪの向上幅が小さいため、本発明の実施形態の粒度で粉砕は行わない。しかし、本発明の実施形態の組成範囲であると大幅にＨｃＪが向上するので、粉砕時間が長くなったとしても行う価値が十分にある。As shown in Table 2, the sample No. For any of the sintered magnets 1 to 27, the particle size D 50 and the particle size D 99 of the finely pulverized powder (alloy powder) used are adjusted to the particle size of the embodiment of the present invention (fine pulverized powder produced under condition B). by, as compared to a regular particle size (prepared under the conditions a), H cJ without loss of B r is improved ([Delta] H cJ is greater than 0). However, the sample No. which does not satisfy the composition of the embodiment of the present invention. In the comparative examples of 15 to 26 , the improvement width (ΔH cJ ) of H cJ of the sintered magnet was 36 to 57 kA / m, which was not sufficient. On the other hand, in the composition range of the embodiment of the present invention (Sample Nos. 1 to 14 and 27), ΔH cJ is 87 to 101 kA / m, which is about 1.5 to 2.5 times that of the comparative example. Improved. Thus, by satisfying the composition of an embodiment of the present invention, a high B r and high H cJ are achieved. As described above, by changing from condition A (normal particle size) to condition B (particle size of the embodiment of the present invention), the pulverization time becomes as long as 10 to 40 minutes. Therefore, if the composition of the embodiment of the present invention is not satisfied, the improvement range of HcJ is small, and therefore the pulverization is not performed at the particle size of the embodiment of the present invention. However, in the composition range of the embodiment of the present invention, HcJ is significantly improved, so that it is sufficiently worthwhile even if the pulverization time is long.

ここで、表１に示すＢ量と、表２および３に示した保磁力の向上幅ΔＨｃＪとの関係を図１に示す。図１は、縦軸に本発明例及び比較例のΔＨｃＪを、横軸にＢ量を示したものである。図１における四角のプロット（■）が本発明例であり、三角のプロット（▲）が比較例である。図１に示すように、Ｂ量が０．８５０〜０．９１０質量％と極めて狭い範囲において高いΔＨｃＪが得られていることが分かる。また、Ｂ量が０．８７０〜０．９１０質量％の方がさらに高い（９０ｋＡ／ｍ以上）ΔＨｃＪが得られている。Here, FIG. 1 shows the relationship between the amount of B shown in Table 1 and the improvement width ΔH cJ of the coercive force shown in Tables 2 and 3. In FIG. 1, the vertical axis shows ΔH cJ of the examples of the present invention and the comparative example, and the horizontal axis shows the amount of B. The square plot (■) in FIG. 1 is an example of the present invention, and the triangular plot (▲) is a comparative example. As shown in FIG. 1, it can be seen that a high ΔH cJ is obtained in an extremely narrow range where the amount of B is 0.850 to 0.910% by mass. Further, when the amount of B is 0.870 to 0.910% by mass, a higher ΔH cJ (90 kA / m or more) is obtained.

また、表３に示すように、微粉砕粉（合金粉末）における粒径Ｄ５０及び粒径Ｄ９９が本発明の実施形態の好ましい範囲（３．８μｍ≦Ｄ５０≦４．５μｍ及びＤ９９≦９μｍ）であると、Ｂｒの低下なしにΔＨｃＪが１７３ｋＡ／ｍと、さらに高いＢｒと高いＨｃＪが得られている。Further, as shown in Table 3, the particle size D 50 and the particle size D 99 in the finely pulverized powder (alloy powder) are in the preferable range (3.8 μm ≦ D 50 ≦ 4.5 μm and D 99 ≦) of the embodiment of the present invention. If it is 9 .mu.m), without loss of B r is [Delta] H cJ and 173kA / m, even higher B r and high H cJ are achieved.

本出願は、出願日が２０１６年３月１７日である日本国特許出願、特願第２０１６−０５４１５３号を基礎出願とする優先権主張を伴う。特願第２０１６−０５４１５３号は参照することにより本明細書に取り込まれる。 This application is accompanied by a priority claim based on Japanese Patent Application No. 2016-054153, which has a filing date of March 17, 2016. Japanese Patent Application No. 2016-054153 is incorporated herein by reference.

Claims (3)

Ｒ：２８．５〜３３．０質量％（Ｒは希土類元素のうち少なくとも１種であり、ＮｄおよびＰｒの少なくとも１種を含む）、
Ｂ：０．８７０〜０．８９９質量％、
Ｇａ：０．２〜０．７質量％、
Ｃｕ：０．１〜０．３質量％、
Ａｌ：０．０５〜０．５０質量％、を含有し、
残部がＴ（ＴはＦｅとＣｏであり、Ｔの９０質量％以上がＦｅである）および不可避的不純物であり、下記式（１）を満足するＲ−Ｔ−Ｂ系焼結磁石の製造方法であって、

１４［Ｂ］／１０．８＜［Ｔ］／５５．８５ （１）
（［Ｂ］は質量％で示すＢの含有量であり、［Ｔ］は質量％で示すＴの含有量である）

粒径Ｄ５０および粒径Ｄ９９が下記式（２）および（３）を満足する合金粉末を準備する工程と、
３．８μｍ≦Ｄ５０≦５．５μｍ （２）
Ｄ９９≦１０μｍ （３）
前記合金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、
前記焼結体に熱処理を施す熱処理工程と、
を含む、Ｒ−Ｔ−Ｂ系焼結磁石の製造方法。 R: 28.5 to 33.0% by mass (R is at least one rare earth element and contains at least one of Nd and Pr),
B: 0.870 to 0.899 % by mass,
Ga: 0.2 to 0.7% by mass,
Cu: 0.1 to 0.3 % by mass,
Al: contains 0.05 to 0.50% by mass,
A method for producing an RTB-based sintered magnet in which the balance is T (T is Fe and Co, and 90% by mass or more of T is Fe) and unavoidable impurities, and the following formula (1) is satisfied. And

14 [B] /10.8 <[T] /55.85 (1)
([B] is the content of B indicated by mass%, and [T] is the content of T indicated by mass%)

A step of preparing an alloy powder in which the particle size D 50 and the particle size D 99 satisfy the following formulas (2) and (3), and
3.8 μm ≤ D 50 ≤ 5.5 μm (2)
D 99 ≤ 10 μm (3)
A molding process of molding the alloy powder to obtain a molded product,
A sintering step of sintering the molded body to obtain a sintered body,
A heat treatment step of heat-treating the sintered body and
A method for producing an RTB-based sintered magnet, which comprises. 前記Ｒ−Ｔ−Ｂ系焼結磁石におけるＣｕが０．２〜０．３質量％である、請求項１に記載のＲ−Ｔ−Ｂ系焼結磁石の製造方法。 The Cu in the R-T-B based sintered magnet Ru 0.2 to 0.3% by mass, the production method of the R-T-B based sintered magnet according to claim 1. 前記粒径Ｄ５０および粒径Ｄ９９がさらに下記式（４）および（５）を満足する、請求項１又は２に記載のＲ−Ｔ−Ｂ系焼結磁石の製造方法。
３．８μｍ≦Ｄ５０≦４．５μｍ （４）
Ｄ９９≦９μｍ （５） The method for producing an RTB-based sintered magnet according to claim 1 or 2, wherein the particle size D 50 and the particle size D 99 further satisfy the following formulas (4) and (5).
3.8 μm ≤ D 50 ≤ 4.5 μm (4)
D 99 ≤ 9 μm (5)
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