JPH1032133A - Manufacture of rare-earth sintered permanent magnet - Google Patents

Manufacture of rare-earth sintered permanent magnet

Info

Publication number
JPH1032133A
JPH1032133A JP8203034A JP20303496A JPH1032133A JP H1032133 A JPH1032133 A JP H1032133A JP 8203034 A JP8203034 A JP 8203034A JP 20303496 A JP20303496 A JP 20303496A JP H1032133 A JPH1032133 A JP H1032133A
Authority
JP
Japan
Prior art keywords
powder
binder
granulated
alloy powder
rare earth
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP8203034A
Other languages
Japanese (ja)
Other versions
JP3631330B2 (en
Inventor
Osamu Yamashita
治 山下
Akira Makita
顕 槇田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Metals Ltd
Original Assignee
Sumitomo Special Metals Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Special Metals Co Ltd filed Critical Sumitomo Special Metals Co Ltd
Priority to JP20303496A priority Critical patent/JP3631330B2/en
Publication of JPH1032133A publication Critical patent/JPH1032133A/en
Application granted granted Critical
Publication of JP3631330B2 publication Critical patent/JP3631330B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00Apparatus 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
    • H01F41/02Apparatus 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
    • H01F41/0253Apparatus 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 for manufacturing permanent magnets
    • H01F41/0266Moulding; Pressing
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032Magnets 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
    • H01F1/04Magnets 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
    • H01F1/047Alloys characterised by their composition
    • H01F1/053Alloys characterised by their composition containing rare earth metals
    • H01F1/055Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/0551Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0552Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 in the form of particles, e.g. rapid quenched powders or ribbon flakes with a protective layer
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032Magnets 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
    • H01F1/04Magnets 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
    • H01F1/047Alloys characterised by their composition
    • H01F1/053Alloys characterised by their composition containing rare earth metals
    • H01F1/055Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0572Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes with a protective layer

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Powder Metallurgy (AREA)
  • Hard Magnetic Materials (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide the method with which a thin film, small-type and complicatedly shaped R-Fe-B and R-Co rare-earth sintered permanent magnet, on which the reaction between alloy powder and a binder is suppressed, the amount of residual oxygen and carbon of a sintered body is reduced, the fluidity and the lubricating property of the granulated powder is improved, magnetic characteristics are enhanced and dimensional accuracy is superior, can be obtained in a stable and efficiency manner. SOLUTION: After a hydrophobic nature has been imparted to rare-earth alloy powder with an organic metal compound, the powder is granulated while a binder is being atomized and added in the chamber of a fluidized bed granulating device, the granulated material is agitated using hot gas and an agitating blade 2, and granulated powder is formed by drying. By the formation of a sintered magnet, using the granulated powder by conducting a powder metallurgy, the fluidity of the powder, when powder is supplied before compression molding and a compression molding operation is conducted, can be improved, the cycle of molding and the dimensional accuracy of th molded body can be improved, and the oxidation reaction with the water in the binder can be suppressed by hydrophobic treatment. As a result, sintered magnet, having superior magnetic characteristics, can be manufactured in a stable and efficient manner.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】この発明は、R−Fe−B系
合金やR−Co系合金などの希土類(R)含有合金から
なる造粒粉を用いた焼結永久磁石の製造方法に係り、該
希土類合金粉末に疎水処理した後、流動造粒装置のチャ
ンバー内でバインダーを噴霧添加しながら造粒し、熱風
ガスと撹拌羽根で撹拌、乾燥して造粒粉となし、該造粒
粉を粉末冶金法によって焼結体とすることにより、圧縮
成形前の給粉時及び圧縮成形時の粉体の流動性、潤滑性
を向上させて、成形サイクルの向上、成形体の寸法精度
を向上させ、また予め疎水処理してバインダー中の水と
の酸化反応を抑制したことにより、磁気特性の優れた焼
結磁石を製造することができる希土類焼結永久磁石の製
造方法に関する。
The present invention relates to a method for producing a sintered permanent magnet using granulated powder comprising a rare earth (R) -containing alloy such as an R-Fe-B alloy or an R-Co alloy. After the hydrophobic treatment of the rare earth alloy powder, the mixture is granulated while spraying and adding a binder in a chamber of a fluidized granulation apparatus, stirred with hot air gas and a stirring blade, and dried to form a granulated powder. By making it a sintered body by powder metallurgy, it improves the fluidity and lubricity of the powder at the time of powdering and compression molding before compression molding, improves the molding cycle, and improves the dimensional accuracy of the molded body. Also, the present invention relates to a method for manufacturing a rare earth sintered permanent magnet capable of manufacturing a sintered magnet having excellent magnetic properties by preliminarily performing a hydrophobic treatment to suppress an oxidation reaction with water in a binder.

【0002】[0002]

【従来の技術】今日、家電製品を初めコンピュータの周
辺機器や自動車等の用途に用いられる小型モーターやア
クチュエータ等には、小型化、軽量化とともに高性能化
が求められており、その磁石材料も小型化、軽量化、薄
肉化が要求されている。
2. Description of the Related Art Today, small motors and actuators used for home appliances, computer peripherals, automobiles, and other applications are required to be smaller, lighter, and have higher performance. There is a demand for miniaturization, weight reduction, and thinning.

【0003】現在の代表的な焼結永久磁石材料として
は、フェライト磁石、R−Co系磁石、そして、出願人
が先に提案したR−Fe−B系磁石(特公昭61−34
242号等)が挙げられる。上記の中でも、特に、R−
Co系磁石やR−Fe−B系磁石などの希土類磁石は、
他の磁石材料に比べて磁気特性が格段にすぐれるため
に、各種用途に多用されている。
[0003] Typical representative sintered permanent magnet materials at present include ferrite magnets, R-Co based magnets, and R-Fe-B based magnets previously proposed by the applicant (Japanese Patent Publication No. 61-34).
242). Among the above, in particular, R-
Rare earth magnets such as Co-based magnets and R-Fe-B-based magnets
Since the magnetic properties are remarkably superior to other magnet materials, they are widely used for various applications.

【0004】特に、R−Fe−B系焼結永久磁石は、最
大エネルギー積((BH)max)が40MGOeを超
え、最大では50MGOeを超える極めて優れた磁気特
性を有するが、それを発現させるためには、所要組成か
らなる合金を1〜10μm程度の平均粒度に粉砕するこ
とが必要となる。また、合金粉末の粒度を小さくする
と、成形時の粉末の流動性が悪くなり、成形体密度のバ
ラツキや成形機の寿命を低下させるとともに、焼結後の
寸法精度にもバラツキを生じることとなり、特に薄肉形
状や小型形状の製品を得るのが困難であった。
[0004] In particular, the R-Fe-B sintered permanent magnet has extremely excellent magnetic properties having a maximum energy product ((BH) max) of more than 40 MGOe and a maximum of more than 50 MGOe. It is necessary to pulverize an alloy having a required composition to an average particle size of about 1 to 10 μm. In addition, when the particle size of the alloy powder is reduced, the fluidity of the powder during molding becomes worse, and the dispersion of the compact density and the life of the molding machine are reduced, and the dimensional accuracy after sintering also varies, In particular, it has been difficult to obtain products having a thin or small shape.

【0005】また、希土類系磁石は、希土類元素や鉄を
主成分として大気中で酸化し易い合金組織などを含有す
るため、合金粉末の粒度を小さくすると、酸化により磁
気特性が劣化する問題があり、特にR−Fe−B系焼結
永久磁石は、従来から知られる希土類コバルト磁石等に
比べ極めて優れた磁気特性を発現するという特徴を有す
るが、その磁気特性の発源となる希土類やBとの新たな
組織の特定の化合物や化合物相が活性なため、合金粉末
の粒度を小さくすると、酸化により磁気特性が劣化する
問題もあった。
[0005] Further, since rare earth magnets contain a rare earth element or iron as a main component and an alloy structure easily oxidized in the atmosphere, there is a problem that if the particle size of the alloy powder is reduced, the magnetic properties are deteriorated due to oxidation. In particular, R-Fe-B based sintered permanent magnets have the feature of exhibiting extremely superior magnetic properties as compared with conventionally known rare earth cobalt magnets and the like. Since the specific compound or compound phase of the new structure is active, there is also a problem that when the particle size of the alloy powder is reduced, the magnetic properties are deteriorated by oxidation.

【0006】[0006]

【発明が解決しようとする課題】そのため、特に成形性
を改良するために、成形前の合金粉末に、ポリオキシエ
チレンアルキルエーテル等を添加したもの(特公平4−
80961号)、それらにさらにパラフィンやステアリ
ン酸塩を添加したもの(特公平4−80962号、特公
平5−53842号)、またオレイン酸を添加したもの
(特公昭62−36365号)などが提案された。しか
し、ある程度の成形性は向上できるものの、その改善効
果にも限界があり、近年要求される薄肉形状や小型形状
の成形は依然困難であった。
Therefore, in order to improve the moldability in particular, an alloy powder before molding is added with polyoxyethylene alkyl ether or the like (Japanese Patent Publication No. Hei 4-
No. 80961), those further added with paraffin or stearate (Japanese Patent Publication No. 4-80962, Japanese Patent Publication No. 5-53842), and those added with oleic acid (Japanese Patent Publication No. 62-36365). Was done. However, although the moldability can be improved to some extent, the effect of the improvement is limited, and it has been still difficult to form a thin or small shape required in recent years.

【0007】また、上記のバインダーや潤滑剤の添加と
ともに、さらに成形性を改良し、薄肉形状品や小型形状
品を製造する方法として、成形前の合金粉末に飽和脂肪
族カルボン酸や不飽和脂肪族カルボン酸にミリスチル酸
エチルやオレイン酸からなる滑剤を添加して混練した
後、造粒を行なって成形する方法(特開昭62−245
604号)、あるいはパラフィン混合物に飽和脂肪族カ
ルボン酸や不飽和脂肪族カルボン酸等を添加、混練後、
造粒した後成形する方法(特開昭63−237402
号)も提案されている。しかし、上記の方法では、粉末
粒子の結合力が十分でなく、造粒粉が壊れやすいため
に、十分な粉末の流動性を実現することが困難であっ
た。
[0007] In addition to the addition of the above-mentioned binder and lubricant, a method for further improving the moldability and producing a thin-walled product or a small-sized product has been proposed by adding a saturated aliphatic carboxylic acid or unsaturated fatty acid to an alloy powder before molding. A method comprising adding a lubricant consisting of ethyl myristylate or oleic acid to an aromatic carboxylic acid, kneading the mixture, and granulating the mixture to form the mixture (Japanese Patent Laid-Open No. Sho 62-245).
No. 604), or after adding a saturated aliphatic carboxylic acid or an unsaturated aliphatic carboxylic acid to a paraffin mixture, kneading,
A method of forming after granulation (JP-A-63-237402)
No.) has also been proposed. However, in the above-mentioned method, the bonding force of the powder particles is not sufficient, and the granulated powder is easily broken, so that it has been difficult to realize sufficient fluidity of the powder.

【0008】成形性を向上させたり、粉末粒子の結合力
を高めるためには、種々バインダーや潤滑剤の添加量を
増やすことが考えられるが、多量に添加すると、希土類
系合金粉末中のR成分とバインダーとの反応により、焼
結後の焼結体の残留酸素量、残留炭素量が増加し、磁気
特性の劣化を招くことになるので、添加量にも制限があ
った。
[0008] In order to improve the moldability and enhance the bonding strength of the powder particles, it is conceivable to increase the amount of various binders and lubricants. However, if the amount is large, the R component in the rare-earth alloy powder may be increased. The reaction between the binder and the binder increases the amount of residual oxygen and the amount of residual carbon in the sintered body after sintering, thereby deteriorating the magnetic properties.

【0009】また、希土類系合金粉末を対象とするもの
ではないが、Co系スーパーアロイ粉末を対象とした圧
縮成形用のバインダーとして、対象合金粉末に対して、
1.5〜3.5wt%のメチルセルロースとさらに所定
量の添加物であるグリセリンとほう酸を混合した組成が
提案(USP4,118,480)され、また、工具用
合金粉末の射出成形用のバインダーとして、特殊組成か
らなり、対象合金粉末に対して0.5〜2.5wt%の
メチルセルロースに水、グリセリン等の可塑剤、ワック
スエマルジョン等の滑剤、離型剤を添加した組成が提案
(特開昭62−37302号)されている。
[0009] Although not intended for rare earth alloy powders, it is used as a binder for compression molding for Co superalloy powders.
A composition in which 1.5 to 3.5 wt% of methylcellulose and a predetermined amount of additives glycerin and boric acid are mixed has been proposed (US Pat. No. 4,118,480), and as a binder for injection molding of alloy powder for tools. A composition comprising a special composition, 0.5 to 2.5% by weight of methylcellulose based on the target alloy powder and water, a plasticizer such as glycerin, a lubricant such as a wax emulsion, and a release agent is proposed (Japanese Patent Application Laid-Open No. 62-37302).

【0010】しかし、それらはいずれも所定の流動性と
成形体強度を確保するため、いずれも対象合金粉末に対
して、上記のように例えば0.5wt%以上もの比較的
多量のバインダーを使用するもので、しかも種々のバイ
ンダー添加剤の添加、例えばグリセリン等の可塑剤をメ
チルセルロースと同量程度添加することが不可欠である
ため、射出成形や圧縮成形後、脱脂した後、焼結後でも
かなりの炭素と酸素が残留し、特にこの発明の対象とす
るR−Fe−B系などの希土類系焼結磁石の場合、磁気
の劣化を招くので、容易には適用できない。
However, in each case, in order to ensure predetermined fluidity and strength of the compact, a relatively large amount of binder, for example, 0.5 wt% or more is used for the target alloy powder as described above. In addition, since it is essential to add various binder additives, for example, a plasticizer such as glycerin in the same amount as methylcellulose, after injection molding or compression molding, after degreasing, even after sintering Carbon and oxygen remain, and particularly in the case of rare-earth sintered magnets such as R-Fe-B-based magnets which are the subject of the present invention, they cause deterioration of magnetism and cannot be easily applied.

【0011】また、フェライトなどの酸化物粉末を対象
として、平均粒度1μm以下の粉末に、バインダーとし
て0.6〜1.0wt%のポリビニルアルコールを添加
したのち、スプレードライヤー装置により造粒粉を製造
し、該造粒粉を成形、焼結する方法が知られている。
In addition, for an oxide powder such as ferrite, a powder having an average particle size of 1 μm or less is added with 0.6 to 1.0% by weight of polyvinyl alcohol as a binder, and then a granulated powder is produced by a spray drier. Then, a method of molding and sintering the granulated powder is known.

【0012】しかし、上記方法はいずれも酸化物粉末に
対して0.6wt%以上もの多量のバインダーを使用す
るもので、脱脂処理を施したのちの焼結体にもかなりの
炭素及び酸素が残留するため、非常に酸化及び炭化しや
すい性質を有し、少しの酸化あるいは炭化によっても極
端に磁気特性が劣化するこの発明の対象とする希土類含
有合金粉末に、上記のような酸化物を対象とした方法を
そのまま適用することはできない。
However, all of the above methods use a large amount of a binder as much as 0.6 wt% or more with respect to the oxide powder, and considerable carbon and oxygen remain in the sintered body after degreasing. Therefore, the rare earth-containing alloy powder of the present invention, which has a property of being very easily oxidized and carbonized, and whose magnetic properties are extremely deteriorated by a small amount of oxidation or carbonization, is intended for the above oxides. It is not possible to apply the method as it is.

【0013】特に、酸化物の場合は比較的多量のバイン
ダーを用いても大気中で脱脂、焼結できるため、脱脂、
焼結時にバインダーが燃焼してある程度の残留炭素の抑
制を図ることができるが、この発明の対象とする希土類
含有合金粉末の場合は、酸化により磁気特性が劣化する
ため大気中で脱脂、焼結することができないので、多量
のバインダー添加は得られる焼結磁石の磁気特性に致命
的な悪影響を及ぼすこととなる。
Particularly, in the case of oxides, degreasing and sintering can be performed in the air even if a relatively large amount of binder is used.
Although the binder burns during sintering, a certain amount of residual carbon can be suppressed.However, in the case of the rare earth-containing alloy powder, which is the object of the present invention, the magnetic properties are deteriorated due to oxidation, so that degreasing and sintering are performed in air. Therefore, the addition of a large amount of binder has a fatal adverse effect on the magnetic properties of the obtained sintered magnet.

【0014】このように、希土類系焼結永久磁石の製造
方法において、成形前の合金粉末に、種々のバインダー
や潤滑剤を添加したり、さらに造粒を行なって、成形性
を改良する試みが種々提案されてはいるが、いずれの方
法によっても、近年要求されるような、磁気特性が高
く、寸法精度のすぐれた薄肉形状や小型、複雑形状の希
土類系焼結永久磁石を製造するのは困難であった。
As described above, in the method for producing a rare earth sintered permanent magnet, attempts have been made to improve the formability by adding various binders and lubricants to the alloy powder before compaction and further performing granulation. Although various proposals have been made, it is difficult to produce a rare-earth sintered permanent magnet having high magnetic properties, high dimensional accuracy, a thin-walled shape, a small size, and a complicated shape, as required in recent years, by any method. It was difficult.

【0015】この発明は、粉末冶金法により希土類系焼
結永久磁石を製造する方法において、合金粉末とバイン
ダーとの反応を抑制し、焼結体の残留酸素量、残留炭素
量を低減させるとともに、成形時の造粒粉の流動性、潤
滑性を向上させて、磁気特性が高く、寸法精度のすぐれ
た薄肉形状や小型、複雑形状のR−Fe−B系やR−C
o系などの希土類系焼結永久磁石が安定的に効率よく得
られる製造方法の提供を目的とする。
According to the present invention, in a method of manufacturing a rare earth sintered permanent magnet by powder metallurgy, a reaction between an alloy powder and a binder is suppressed, and a residual oxygen amount and a residual carbon amount of a sintered body are reduced. Improves the fluidity and lubricity of the granulated powder during molding, has high magnetic properties, has excellent dimensional accuracy, and has thin, small, and complex R-Fe-B and RC shapes.
It is an object of the present invention to provide a manufacturing method capable of stably and efficiently obtaining a rare earth-based sintered permanent magnet such as an o-based.

【0016】[0016]

【課題を解決するための手段】発明者らは、成形性の良
好な造粒粉を容易に製造できる製造方法について種々検
討した結果、希土類合金粉末にステアリン酸亜鉛粉末等
の有機金属化合物を添加し、混練被覆して疎水処理した
磁性粉末を、流動造粒装置に装入してチャンバー内で水
溶性ポリマーと水とからなるバインダーを噴霧添加しな
がら、流動粉体層を熱風ガスと撹拌羽根で撹拌、乾燥す
ることによって、造粒粉となすことができること、さら
に、該造粒粉を用いて成形すると、造粒粉自体が十分な
結合力を有するために、粉体の流動性が格段に向上し、
成形体密度のバラツキや成形機の寿命を低下させること
もなく、焼結後の寸法精度にも優れ、薄肉形状や小型形
状でかつ優れた磁気特性を有する希土類系焼結永久磁石
が効率よく得られることを知見し、この発明を完成し
た。
Means for Solving the Problems The inventors of the present invention have conducted various studies on a production method capable of easily producing granulated powder having good moldability. As a result, an organic metal compound such as zinc stearate powder was added to a rare earth alloy powder. The magnetic powder which has been kneaded, coated, and hydrophobically treated is charged into a fluidized-granulation apparatus, and a binder composed of a water-soluble polymer and water is spray-added in a chamber while the fluidized powder layer is heated with hot air gas and stirring blades. Can be formed into a granulated powder by stirring and drying, and when molded using the granulated powder, the granulated powder itself has a sufficient binding force, so that the fluidity of the powder is remarkably high. To improve
Efficiently obtains rare-earth sintered permanent magnets that are excellent in dimensional accuracy after sintering, thin and compact, and have excellent magnetic properties without causing variations in compact density or shortening the life of the molding machine. That is, the present invention was completed.

【0017】すなわち、この発明は、有機金属化合物に
て疎水処理した希土類含有合金粉末を流動造粒装置に装
入し、水溶性ポリマーと水とからなるバインダーを噴霧
添加しながら、該合金粉末を熱風ガスと撹拌羽根で撹
拌、乾燥することにより造粒粉となし、該造粒粉を用い
て磁場中で圧縮成形した後、焼結する粉末冶金法により
焼結永久磁石を製造する希土類焼結永久磁石の製造方法
である。
That is, according to the present invention, a rare earth-containing alloy powder which has been subjected to a hydrophobic treatment with an organometallic compound is charged into a fluidized-granulation apparatus, and while a binder comprising a water-soluble polymer and water is added by spraying, the alloy powder is removed. Rare-earth sintering to produce sintered permanent magnets by powder metallurgy, which is made into granulated powder by stirring and drying with hot air gas and stirring blades, and then subjected to compression molding in a magnetic field using the granulated powder and then sintering. This is a method for manufacturing a permanent magnet.

【0018】また、この発明は、上記の製造方法におい
て、疎水処理用の有機金属化合物は、ステアリン酸亜
鉛、ステアリン酸ニッケル、ステアリン酸カルシウム、
ステアリン酸アルミニウム、ステアリン酸銅のうち1種
であり、添加量は0.01〜0.20wt%である製造
方法、疎水処理した希土類含有合金粉末の平均粒度が1
μm〜10μmである製造方法、水溶性バインダーがセ
ルロースエーテル、ポリビニールアルコールを水に溶解
したバインダーで、含有量が0.05wt%〜0.5w
t%である製造方法、噴霧バインダーのバインダー濃度
は1〜10wt%である製造方法、熱風ガス温度が60
℃〜150℃である製造方法、磁場中で圧縮成形は、静
磁場および/またはパルス磁場中で圧縮成形する製造方
法、造粒粉の平均粒度が20μm〜400μmである製
造方法を併せて提案する。
Further, in the present invention, in the above-mentioned production method, the organometallic compound for the hydrophobic treatment may be zinc stearate, nickel stearate, calcium stearate,
A production method in which one of aluminum stearate and copper stearate is added and the amount of addition is 0.01 to 0.20 wt%, and the average particle size of the hydrophobically treated rare earth-containing alloy powder is 1
The production method is from 10 μm to 10 μm, the water-soluble binder is a binder obtained by dissolving cellulose ether and polyvinyl alcohol in water, and the content is 0.05 wt% to 0.5 w
t%, the binder concentration of the spray binder is 1 to 10 wt%, and the hot air gas temperature is 60%.
C. to 150.degree. C., compression molding in a magnetic field, a compression molding method in a static magnetic field and / or a pulsed magnetic field, and a production method in which the average particle size of the granulated powder is 20 .mu.m to 400 .mu.m are also proposed. .

【0019】また、この発明は、上記の製造方法におい
て、バインダーの噴霧添加を不活性ガス雰囲気中で実施
し、かつバインダー中の水との酸化反応を防止するため
に、バインダー添加中は流動粉体層の温度を0℃〜30
℃の範囲に抑え、添加後の熱風ガスと撹拌羽根による撹
拌、乾燥時には80℃〜120℃に短時間温度を上昇さ
せて温度制御する製造方法を併せて提案する。
Further, in the present invention, in the above-mentioned production method, in order to carry out the spray addition of the binder in an inert gas atmosphere and to prevent an oxidation reaction with water in the binder, the powder is added during the addition of the binder. 0 ℃ -30
In addition, a manufacturing method is proposed in which the temperature is controlled to a temperature of 80 ° C. to 120 ° C. for a short time during stirring and drying with hot air gas and a stirring blade after addition, while controlling the temperature to 80 ° C.

【0020】[0020]

【発明の実施の形態】この発明において、造粒粉の製造
を行うための流動造粒装置の構成とその作用を図面に基
づいて詳述する。図1はこの発明で用いる流動造粒装置
の概略説明図である。流動造粒装置は、筒状の流動層チ
ャンバー1からなり、流動層チャンバー1底にはチャン
バー内に装入された粉体を撹拌するための撹拌羽根2が
配設され、同時にヒーター3で加熱されガス温度制御装
置4で温度制御された不活性ガスがチャンバー1底の噴
射口5より噴出する構成である。
BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the structure and operation of a fluidized-granulation apparatus for producing granulated powder will be described in detail with reference to the drawings. FIG. 1 is a schematic explanatory view of a fluidized-granulation apparatus used in the present invention. The fluidized-granulation apparatus includes a cylindrical fluidized-bed chamber 1, and a stirring blade 2 for stirring powder placed in the chamber is disposed at the bottom of the fluidized-bed chamber 1, and is simultaneously heated by a heater 3. The inert gas whose temperature is controlled by the gas temperature control device 4 is ejected from the ejection port 5 at the bottom of the chamber 1.

【0021】流動造粒装置は、噴射口5より所定温度の
不活性ガスが噴出することにより、粉体を流動層状態に
すると同時に、撹拌羽根2が回転して転動状態となり、
かかる粉体層にバインダーをスプレーノズル6から噴露
し、噴霧された液滴を中心に粉末を凝集させ造粒した
後、この湿った造粒粉を乾燥するために、さらにガス温
度を上げた熱風ガスを噴出させて、水分を吸収した湿っ
た不活性ガスをバグフィルター7を通過させて導出口8
より排気する構成からなり、チャンバー1内に装入され
た粉体を造粒する装置である。
In the fluidized-granulation apparatus, when the inert gas at a predetermined temperature is ejected from the injection port 5, the powder is brought into a fluidized bed state, and at the same time, the stirring blade 2 is rotated to be in a rolling state.
After the binder was blown out and sprayed from the spray nozzle 6 on the powder layer, the powder was aggregated around the sprayed droplets and granulated, and then the gas temperature was further increased in order to dry the wet granulated powder. Hot air gas is blown out, and the moist inert gas which has absorbed the moisture is passed through the bag filter 7 and the outlet 8
This is a device that granulates the powder charged in the chamber 1 and has a configuration for more exhausting.

【0022】以上の流動造粒装置おいて、流動層チャン
バー1内に装入された希土類系合金粉末に後述するバイ
ンダーをスプレーノズル6から噴霧添加して、チャンバ
ー1底からの熱風ガスと撹拌羽根2で撹拌、乾燥するこ
とによって造粒粉にする。この機構を説明すると、まず
スプレーノズル6から噴霧された液滴は、ガス流と撹拌
羽根2によって流動している粉体に付着し、その液滴を
中心に粉末が付着凝集して成長して2次粒子を形成し、
この2次粒子は次に熱風ガスによって乾燥されて造粒粉
となる。
In the above-mentioned fluidized-granulation apparatus, a binder, which will be described later, is spray-added from the spray nozzle 6 to the rare-earth alloy powder charged in the fluidized-bed chamber 1, and hot air gas from the bottom of the chamber 1 and stirring blades The mixture is stirred at 2 and dried to form granulated powder. This mechanism will be described. First, the droplet sprayed from the spray nozzle 6 adheres to the powder flowing by the gas flow and the stirring blade 2, and the powder adheres and aggregates around the droplet to grow. Forming secondary particles,
The secondary particles are then dried by hot air gas to form granulated powder.

【0023】この発明において、流動造粒装置は、造粒
する磁性粉末が、希土類含有合金粉末の場合には、粉末
が非常に酸化し易いために、装置のチャンバー内の流動
層を不活性ガスなどで置換でき、かつその酸素濃度を3
wt%以下に保持できる構造であることが好ましい。ま
た、ガスの排出口には、チャンバー内のガス圧が上昇し
ないように、また流動層中の粉末がチャンバー外に出な
いようにフィルターを設けることが必要である。
In the present invention, when the magnetic powder to be granulated is a rare earth-containing alloy powder, the powder is very easily oxidized, so that the fluidized bed in the chamber of the apparatus is inert gas. And the oxygen concentration is 3
It is preferable that the structure can be maintained at not more than wt%. Further, it is necessary to provide a filter at the gas outlet so that the gas pressure in the chamber does not rise and the powder in the fluidized bed does not go out of the chamber.

【0024】また、流動造粒装置の構成としては、上述
したチャンバー内のスプレーノズルにより噴霧された液
滴を中心に粉末を凝集させるために、チャンバーの下部
に不活性ガスを噴射する噴射口を配置し、またチャンバ
ーの上部に噴射されたガスをチャンバー外へ排出する排
出口を設けるが、その際、バインダー添加中は該合金粉
末層の温度を0℃〜30℃の範囲に抑え、添加後の熱風
ガスと撹拌羽根による撹拌、乾燥時には80℃〜120
℃に上昇させて温度制御することが望ましい。
Further, as a configuration of the fluidized-granulation apparatus, an injection port for injecting an inert gas into a lower portion of the chamber is provided in order to agglomerate the powder around the droplet sprayed by the spray nozzle in the chamber. In addition, an outlet is provided for discharging the gas injected into the upper part of the chamber to the outside of the chamber. At this time, the temperature of the alloy powder layer is kept in the range of 0 ° C. to 30 ° C. during the addition of the binder. 80 ° C. to 120 ° C. when stirring with hot air gas and stirring blades and drying.
It is desirable to control the temperature by raising the temperature to ° C.

【0025】その理由は、希土類含有合金粉末とバイン
ダー中の水との反応による酸化を極力抑制するためであ
り、0℃〜30℃の範囲では酸化がほとんど進行せず、
バインダー添加後の撹拌、乾燥時には、80℃〜120
℃に上昇させて、短時間で乾燥を完了させるためであ
る。
The reason for this is to minimize the oxidation caused by the reaction between the rare earth-containing alloy powder and water in the binder. Oxidation hardly proceeds in the range of 0 ° C. to 30 ° C.
At the time of stirring and drying after adding the binder,
This is for raising the temperature to ° C. to complete the drying in a short time.

【0026】さらに、予め装置外部あるいは装置に付属
された加熱器で所要温度に加熱された不活性ガスの温度
を低下させないように、上記噴射口を不活性ガスの温度
に応じた温度、例えば、60℃〜150℃に保持するこ
とが好ましい。すなわち、不活性ガスの温度が低下する
と、噴霧された液滴によって造粒された2次粒子が短時
間に乾燥できなくなるために、処理時間が長くなり能率
が低下してしまうためである。
Further, in order not to lower the temperature of the inert gas which has been heated to a required temperature outside of the apparatus or by a heater attached to the apparatus, the injection port is set at a temperature corresponding to the temperature of the inert gas, for example, It is preferable to maintain the temperature at 60C to 150C. That is, when the temperature of the inert gas is reduced, the secondary particles granulated by the sprayed droplets cannot be dried in a short time, so that the processing time is increased and the efficiency is reduced.

【0027】得られる造粒粉の粒径は、流動造粒装置へ
供給する噴霧用バインダーの添加量、原料の処理量ある
いは乾燥時のガス流の温度と流量によって制御すること
ができるが、例えば、希土類含有合金粉末の平均粒径が
20μm未満では、造粒粉の流動性が殆ど向上せず、ま
た、平均粒径が400μmを超えると、粒径が大きすぎ
て成形略の金型内への充填密度が低下するとともに成形
体密度も低下し、ひいては、焼結後の焼結体密度の低下
をきたすこととなるため好ましくなく、よって、造粒粉
の平均粒径は20〜400μmが好ましい。さらに好ま
しくは50〜200μmである。
The particle size of the obtained granulated powder can be controlled by the addition amount of the spray binder to be supplied to the fluidized granulation device, the processing amount of the raw material, or the temperature and flow rate of the gas flow at the time of drying. If the average particle size of the rare earth-containing alloy powder is less than 20 μm, the fluidity of the granulated powder is hardly improved, and if the average particle size exceeds 400 μm, the particle size is too large and the metal powder is almost not formed into a mold. As the packing density of the powder decreases, the density of the compact also decreases, which in turn leads to a reduction in the density of the sintered compact after sintering. Therefore, the average particle size of the granulated powder is preferably 20 to 400 μm. . More preferably, it is 50 to 200 μm.

【0028】また、比較的大きな粒径の造粒粉を作る場
合は、バインダー添加量を増やすか、もしくは乾燥時の
ガス流量を減らして乾燥時に造粒粉が壊れないようにす
るかのいずれかの方法しかないが、いずれの場合でも造
粒粉中の残留酸素量が増加するために、焼結体にした時
の磁気特性が低下するので、大きな粒径の造粒粉を作製
することは得策ではない。
When making granulated powder having a relatively large particle size, either increase the amount of binder added or reduce the gas flow rate during drying so that the granulated powder is not broken during drying. In any case, the amount of residual oxygen in the granulated powder increases, so that the magnetic properties of the sintered body are reduced. Not a good idea.

【0029】この発明において、対象とする希土類含有
合金粉末は、希土類元素を含有するいずれの組成のもの
も適用可能であるが、中でもR−Fe−B系合金粉末
や、R−Co系合金粉末などが最も適している。特に、
希土類含有合金粉末としては、所要組成からなる単一の
合金を粉砕した粉末や、異なる組成の合金を粉砕した
後、混合して所要組成に調整した粉末、保磁力の向上や
製造性を改善するため添加元素を加えたものなど、公知
のR−Fe−B系合金粉末、R−Co系合金粉末を用い
ることができる。
In the present invention, as the target rare earth-containing alloy powder, any composition containing a rare earth element can be applied. Among them, R-Fe-B alloy powder and R-Co alloy powder Is the most suitable. Especially,
As the rare earth-containing alloy powder, a powder obtained by pulverizing a single alloy having a required composition or a powder obtained by pulverizing an alloy having a different composition and then mixing to adjust the required composition, improving coercive force and improving manufacturability Therefore, known R-Fe-B-based alloy powders and R-Co-based alloy powders such as those to which additional elements are added can be used.

【0030】また、R−Fe−B系合金粉末、R−Co
系合金粉末の製造方法も、溶解、粉化法、超急冷法、直
接還元拡散法、水素含有崩壊法、アトマイズ法等の公知
の方法を適宜選定することができ、その粒度も特に限定
しないが、合金粉末の平均粒径が1μm未満では大気中
の酸素あるいはバインダー内の水と反応して酸化し易く
なり、焼結後の磁気特性を低下させる恐れがあるため好
ましくなく、また、10μmを超える平均粒径では粒径
が大きすぎて焼結密度が95%程度で飽和し、該密度の
向上が望めないため好ましくない。よって1〜10μm
の平均粒度が好ましい範囲である。特に好ましくは1〜
6μmの範囲である。
Further, R-Fe-B alloy powder, R-Co
The production method of the system alloy powder can also be appropriately selected from known methods such as melting, pulverizing method, ultra-quenching method, direct reduction diffusion method, hydrogen-containing disintegration method, atomizing method, and the particle size is not particularly limited. When the average particle size of the alloy powder is less than 1 μm, it is not preferable because it easily reacts with oxygen in the air or water in the binder to be oxidized and may deteriorate magnetic properties after sintering, and exceeds 10 μm. The average particle size is not preferable because the particle size is too large and the sintering density is saturated at about 95%, and improvement of the density cannot be expected. Therefore 1 to 10 μm
Is a preferred range. Particularly preferably 1 to
The range is 6 μm.

【0031】この発明において、疎水処理は、希土類含
有合金粉末とバインダーとの反応を抑制するために行う
ものであり、さらに得られる造粒粉の含有水分量が0.
01wt%以下に低減されるため、焼結体の残留酸素量
が大幅に低減される。
In the present invention, the hydrophobic treatment is performed to suppress the reaction between the rare earth-containing alloy powder and the binder.
Since the content is reduced to 01 wt% or less, the amount of residual oxygen in the sintered body is significantly reduced.

【0032】疎水処理用の有機金属化合物としては、ス
テアリン酸亜鉛のほか、ステアリン酸ニッケル、ステア
リン酸カルシウム、ステアリン酸アルミニウム、ステア
リン酸銅等の水に不溶の粉末を用いることができ、希土
類含有合金粉末へのステアリン酸亜鉛粉末の添加被覆方
法として溶解合金の微粉砕前に添加して被覆しても、ま
た微粉砕後に添加して混合しても良い。
As the organometallic compound for the hydrophobic treatment, in addition to zinc stearate, water-insoluble powders such as nickel stearate, calcium stearate, aluminum stearate and copper stearate can be used. As a coating method, zinc stearate powder may be added before the pulverization of the molten alloy and coated, or may be added after the pulverization and mixed.

【0033】希土類含有合金粉末に対するステアリン酸
亜鉛などの有機金属化合物粉末の添加量は、0.01w
t%未満では疎水処理の効果がなく、造粒粉の流動性の
向上は僅かであり、また、0.20wt%を超えると焼
結体中の亜鉛の量が増加して、焼結体の機械強度が大幅
に低下し、また非磁性相の増加により残留磁束密度が低
下するので好ましくない。よって疎水処理用の有機金属
化合物粉末の添加量は、0.01〜0.20wt%が好
ましい。
The amount of the organic metal compound powder such as zinc stearate added to the rare earth-containing alloy powder is 0.01 w
If it is less than t%, there is no effect of the hydrophobic treatment and the fluidity of the granulated powder is slightly improved. If it exceeds 0.20 wt%, the amount of zinc in the sintered body increases, and It is not preferable because the mechanical strength is greatly reduced and the residual magnetic flux density is decreased due to the increase in the non-magnetic phase. Therefore, the addition amount of the organometallic compound powder for the hydrophobic treatment is preferably 0.01 to 0.20 wt%.

【0034】この発明において、疎水処理した希土類含
有合金粉末を造粒するために添加するバインダーとして
は、セルロースエーテルあるいはポリビニーアルコール
を水に溶解したものが好ましい。該ポリマーは少量の添
加量で造粒粉の流動性を向上させることができるととも
に、乾燥後においても強い結合力を有し、さらに希土類
含有合金粉末との反応を抑制することができ、焼結体の
残留酸素量、残留炭素量を低減することができる。
In the present invention, as a binder added for granulating the hydrophobically treated rare earth-containing alloy powder, a binder obtained by dissolving cellulose ether or polyvinyl alcohol in water is preferable. The polymer can improve the fluidity of the granulated powder with a small amount of addition, has a strong bonding force even after drying, can further suppress the reaction with the rare earth-containing alloy powder, and can be sintered. The amount of residual oxygen and carbon in the body can be reduced.

【0035】バインダーは、その添加量を0.5wt%
以下としても、成形時に金型へ粉末を供給するためのフ
ィーダー内における振動にも十分に耐えられる程度の一
次粒子の粒子間結合力と十分な流動性及び成形体強度を
得ることができ、焼結体における残留酸素量、残留炭素
量を低減することができる。
The binder is added in an amount of 0.5 wt%.
Even below, it is possible to obtain the bonding force between the primary particles and the sufficient fluidity and strength of the molded body that can sufficiently withstand the vibration in the feeder for supplying the powder to the mold during molding. It is possible to reduce the amount of residual oxygen and the amount of residual carbon in the formed body.

【0036】バインダーとしてセルロースエーテル或い
はポリビニールアルコールの含有量は、0.05wt%
未満では造粒粉内の粒子間の結合力が弱く成形前の給粉
時に造粒粉が壊れるとともに粉体の流動性が著しく低下
し、また、0.5wt%を超えると焼結体における残留
炭素量と酸素量が増加して保磁力が下がり磁気特性が劣
化するので、0.05wt%〜0.5wt%の含有量が
これらの点で好ましい。
The content of cellulose ether or polyvinyl alcohol as a binder is 0.05 wt%.
If it is less than 5, the bonding force between the particles in the granulated powder is weak, the granulated powder is broken at the time of feeding before compacting, and the fluidity of the powder is significantly reduced. Since the amount of carbon and the amount of oxygen increase and the coercive force decreases and the magnetic properties deteriorate, the content of 0.05 wt% to 0.5 wt% is preferable in these respects.

【0037】この発明において、セルロースエーテルと
は、セルロース骨格の3個の水酸基(−OH)を一部エ
ーテル化剤でエーテル化し、水酸基のかわりにエーテル
基(−OR)を導入した化合物であり、これにはメチル
セルロース(R:CH3)、エチルセルロース(R:C2
5)、ベンジルセルロース(R:CH265)、シア
ンエチルセルロース(R:CH2CH2CN)、トリチル
セルロース(R:C(C653)、カルボキシルメチ
ルセルロース(R:CH2COOM、但しMは、1価の
金属あるいはアンモニウム基)、ヒドロキシプロピルセ
ルロース(R:CH2CH(OH)CH3)、ヒドロキシ
エチルセルロース(R:CH2CH2OH)等があり、こ
れらの置換基を複数個有する、ヒドロキシプロピルメチ
ルセルロース(R:CH2CH2OH、CH3、CH3)、
ヒドロキシエチルメチルセルロース(R:CH2CH3
H、CH3)等を使用することができ、組合せ等に応じ
て、置換基と置換度を選定するとよい。
In the present invention, the cellulose ether is a compound obtained by partially etherifying three hydroxyl groups (—OH) of a cellulose skeleton with an etherifying agent and introducing an ether group (—OR) instead of a hydroxyl group. These include methyl cellulose (R: CH 3 ) and ethyl cellulose (R: C 2
H 5), benzyl cellulose (R: CH 2 C 6 H 5), cyan ethylcellulose (R: CH 2 CH 2 CN ), trityl cellulose (R: C (C 6 H 5) 3), carboxymethyl cellulose (R: CH 2 COOM, where M is a monovalent metal or ammonium group, hydroxypropyl cellulose (R: CH 2 CH (OH) CH 3 ), hydroxyethyl cellulose (R: CH 2 CH 2 OH), etc. Hydroxypropyl methylcellulose (R: CH 2 CH 2 OH, CH 3 , CH 3 ) having a plurality of groups,
Hydroxyethyl methylcellulose (R: CH 2 CH 3 O
H, CH 3 ) and the like can be used, and the substituent and the degree of substitution may be selected according to the combination and the like.

【0038】この発明において、噴霧するバインダーの
濃度は、10wt%を超えるとバインダーの粘度が高く
なり過ぎて、スプレーノズルからバインダーを噴霧する
こと自体が困難になるとともに、仮に噴霧されてもバイ
ンダーが合金粉末と均一に混ざらず、造粒されている所
と造粒されていない所ができる。また濃度が1wt%未
満では含有水分量が多くなり過ぎて、流動層の粉体の乾
燥が困難になり、乾燥時間が長くなるために、希土類合
金粉末が酸化することになる。また使用するガス量も多
くなり、結果的にはコスト高になる。このために、噴霧
バインダーの濃度は1〜10wt%が好ましい範囲であ
る。
In the present invention, if the concentration of the binder to be sprayed exceeds 10 wt%, the viscosity of the binder becomes too high, so that it is difficult to spray the binder from the spray nozzle itself. It does not mix uniformly with the alloy powder, and there are places where granulation has occurred and places where granulation has not occurred. On the other hand, if the concentration is less than 1 wt%, the water content becomes too large, and it becomes difficult to dry the powder in the fluidized bed, and the drying time becomes long, so that the rare earth alloy powder is oxidized. Also, the amount of gas used is increased, resulting in higher costs. For this reason, the concentration of the spray binder is preferably in the range of 1 to 10% by weight.

【0039】また、上述したバインダーにグリセリン、
ワックスエマルジョン、ステアリン酸、フタール酸エス
テル、ペトリオール、グライコール等の分散剤、潤滑剤
のうち少なくとも1種を添加するか、あるいはさらに、
n−オクチルアルコール、ポリアルキレン誘導体、ポリ
エーテル系誘導体等の消泡剤を添加すると、スラリーの
分散性、均一性の向上及びスプレードライヤー装置中で
の粉化状態が良好になり、気泡が少なく、滑り性、流動
性にすぐれる球形の造粒粉を得ることが可能になる。
Further, glycerin,
Add at least one of wax emulsion, stearic acid, phthalic acid ester, petriol, dispersant such as glycol, lubricant, or further,
When an antifoaming agent such as n-octyl alcohol, a polyalkylene derivative, or a polyether derivative is added, the dispersibility of the slurry, the uniformity is improved, and the powdered state in the spray dryer is improved, and the number of bubbles is reduced. It is possible to obtain spherical granulated powder having excellent slipperiness and fluidity.

【0040】なお、分散剤、潤滑剤の添加量は、0.0
3wt%未満の含有量では造粒粉を成形後の離型性改善
に効果がなく、また0.3wt%を超えると焼結体にお
ける残留炭素量と酸素量が増加して保磁力が下がり磁気
特性が劣化するので、0.03wt%〜0.3wt%の
含有量が好ましい。
The amount of the dispersant and lubricant added is 0.0
If the content is less than 3 wt%, there is no effect on improving the releasability after molding the granulated powder, and if it exceeds 0.3 wt%, the residual carbon content and the oxygen content in the sintered body increase, the coercive force decreases, and the magnetism decreases. Since the characteristics are deteriorated, a content of 0.03% by weight to 0.3% by weight is preferable.

【0041】有機金属化合物で疎水処理した希土類含有
合金粉末を用いて、流動造粒した粉末は、含有水分量が
0.01wt%以下と極少量であるために、造粒粉同士
が水分を介して凝集することもなく、それ自体で流動性
に優れた造粒粉であり、また有機金属化合物自体の潤滑
性により、磁場中圧縮成形時の成形圧が下がり、低圧で
高い成形密度の成形体が得られる利点を有する。
The powder obtained by fluid granulation using a rare earth-containing alloy powder that has been subjected to hydrophobic treatment with an organometallic compound has a very small water content of 0.01 wt% or less. It is a granulated powder with excellent fluidity by itself without being agglomerated by itself.Also, due to the lubricity of the organometallic compound itself, the molding pressure during compression molding in a magnetic field is reduced, and a compact with low pressure and high compaction density Is obtained.

【0042】また、得られた造粒粉を篩いによってアン
ダーカット、オーバーカットすることにより流動性に富
んだ造粒粉を得ることができる。さらに、得られた造粒
粉にステアリン酸マグネシウム、ステアリン酸カルシウ
ム、ステアリン酸アルミニウム、ポリエチレングリコー
ル等の潤滑剤を少量添加すると、さらに流動性を向上さ
せることができ有効である。
Further, by subjecting the obtained granulated powder to undercut and overcut by sieving, it is possible to obtain granulated powder having high fluidity. Further, when a small amount of a lubricant such as magnesium stearate, calcium stearate, aluminum stearate, or polyethylene glycol is added to the obtained granulated powder, the fluidity can be further improved, which is effective.

【0043】以上に詳述したごとく、この発明は、R−
Fe−B系合金粉末やR−Co系合金粉末に、有機金属
化合物を添加し、混練被覆して疎水処理した磁性粉末
に、流動造粒装置のチャンバー内で水溶性ポリマーと水
とからなるバインダーを噴霧添加しながら、流動粉体層
を熱風ガスと撹拌羽根で撹拌、乾燥して、造粒粉となす
ことにより、圧縮成形前の給粉時及び圧縮成形時の粉体
の流動性、潤滑性を向上させて、成形サイクルの向上、
成形体の寸法精度を向上させることができる。
As described in detail above, the present invention provides an R-
An organic metal compound is added to an Fe-B-based alloy powder or an R-Co-based alloy powder, and a kneaded, coated, hydrophobically treated magnetic powder is added to a binder comprising a water-soluble polymer and water in a fluidized-granulation apparatus chamber. The fluidized powder layer is agitated with hot air gas and a stirring blade while being spray-added, and then dried to form granulated powder. To improve molding cycle,
The dimensional accuracy of the molded body can be improved.

【0044】また、この発明は、予め疎水処理したこと
から、バインダー中の水との酸化反応が抑制され、希土
類含有合金粉末の表面が有機金属化合物で被覆され、さ
らにその上をバインダーの樹脂の2重で被覆されている
ために、大気中においても酸化し難いので、成形工程に
おける作業性が向上して、高密度で磁気特性の優れた焼
結磁石を製造することができる。
According to the present invention, since the hydrophobic treatment is performed in advance, the oxidation reaction with water in the binder is suppressed, the surface of the rare earth-containing alloy powder is coated with the organometallic compound, and the surface of the rare earth-containing alloy powder is further coated with the resin of the binder. Since it is coated twice, it is hardly oxidized even in the air, so that the workability in the molding step is improved, and a sintered magnet having high density and excellent magnetic properties can be manufactured.

【0045】この発明における造粒粉は、それ自体は等
方性であるので、磁場を印加せずに成形した場合は当然
のことながら等方性の成形体になるが、磁場を印加しな
がら成形すると、圧縮応力と磁場の作用によって、造粒
粉が壊れて元の一次粒子となり、該一次粒子が磁場によ
って配向し、異方性の成形体が得られるので、用途に応
じて等方性磁石と異方性磁石の両方を製造することがで
きるという利点も有する。
Since the granulated powder in the present invention is isotropic in itself, if it is molded without applying a magnetic field, it naturally becomes an isotropic molded body. When molded, the granulated powder is broken by the action of the compressive stress and the magnetic field to become the original primary particles, and the primary particles are oriented by the magnetic field to obtain an anisotropic molded body. It also has the advantage that both magnets and anisotropic magnets can be manufactured.

【0046】この発明による造粒粉を用いて焼結永久磁
石を製造する工程、すなわち、成形、焼結、熱処理など
条件、方法は公知のいずれの粉末冶金的手段を採用する
ことができる。以下に好ましい条件の一例を示す。
The step of manufacturing a sintered permanent magnet using the granulated powder according to the present invention, that is, the conditions and methods such as molding, sintering, and heat treatment, can employ any known powder metallurgy means. An example of preferable conditions is shown below.

【0047】成形は、公知のいずれの成形方法も採用で
きるが、磁場中、圧縮成形で行なうことが最も好まし
く、その圧力は、0.3〜2.0Ton/cm2が好ま
しい。また、磁場は、静磁場単独、パルス磁場単独の
他、静磁場にパルスを上乗せした複合パターン、あるい
は、パルス磁場と静磁場印加を交互に連続して印加する
等の手段を採用することができ、磁場強度としては10
〜20kOeが好ましい範囲である。
The molding can be performed by any known molding method, but is most preferably performed by compression molding in a magnetic field, and the pressure is preferably 0.3 to 2.0 Ton / cm 2 . The magnetic field can be a static magnetic field alone, a pulse magnetic field alone, a composite pattern in which a pulse is added to the static magnetic field, or a means of applying a pulse magnetic field and a static magnetic field alternately and continuously. And the magnetic field strength is 10
-20 kOe is a preferable range.

【0048】焼結前には、真空中で加熱する一般的な方
法や、水素流気中で100〜200℃/時間で昇温し、
300〜600℃で1〜2時間程度保持する方法などに
より脱バインダー処理を行なうことが好ましい。脱バイ
ンダー処理を施すことにより、バインダー中のほぼ全炭
素が脱炭され、磁気特性の向上に繋がる。
Before sintering, a general method of heating in a vacuum or a temperature rise of 100 to 200 ° C./hour in a stream of hydrogen is used.
It is preferable to perform the binder removal treatment by a method of maintaining the temperature at 300 to 600 ° C. for about 1 to 2 hours. By performing the binder removal treatment, almost all carbon in the binder is decarburized, which leads to improvement in magnetic properties.

【0049】なお、R元素を含む合金粉末は、水素を吸
蔵しやすいために、水素流気中での脱バインダー処理後
には脱水素処理工程を行なうことが好ましい。脱水素処
理は、真空中で昇温速度は、50〜200℃/時間で昇
温し、500〜800℃で1〜2時間程度保持すること
により、吸蔵されていた水素はほぼ完全に除去される。
また、脱水素処理後は、引き続いて昇温加熱して焼結を
行うことが好ましく、500℃を超えてからの昇温速度
は任意に選定すればよく、例えば100〜300℃/時
間など、焼結に際して取られる公知の昇温方法を採用で
きる。
Since the alloy powder containing the R element easily absorbs hydrogen, it is preferable to perform a dehydrogenation treatment step after the debinding treatment in a stream of hydrogen. In the dehydrogenation treatment, the stored hydrogen is almost completely removed by raising the temperature in a vacuum at a rate of 50 to 200 ° C./hour and maintaining the temperature at 500 to 800 ° C. for about 1 to 2 hours. You.
In addition, after the dehydrogenation treatment, it is preferable to perform sintering by heating and heating continuously, and the heating rate after exceeding 500 ° C. may be arbitrarily selected, for example, 100 to 300 ° C./hour. A known heating method used for sintering can be employed.

【0050】脱バインダー処理後の成形品の焼結並びに
焼結後の熱処理条件は、選定した合金粉末組成に応じて
適宜選定されるが、焼結並びに焼結後の熱処理条件とし
ては、1000〜1180℃、1〜2時間保持する焼結
工程、450〜800℃、1〜8時間保持する時効処理
工程などが好ましい。
The sintering of the molded article after the binder removal treatment and the heat treatment conditions after the sintering are appropriately selected according to the selected alloy powder composition. A sintering step of holding at 1180 ° C. for 1 to 2 hours and an aging step of holding at 450 to 800 ° C. for 1 to 8 hours are preferable.

【0051】さらに、R−Fe−B系磁性粉中にR成分
とバインダー及び水との反応を抑制するために、従来の
粉末冶金法で一般的に使用されている所要の単一組成の
R−Fe−B系合金原料粉末の代わりに、R2Fe14
相を主相とする平均粒径1〜10μmの主相系合金粉末
と、R3Co相を含むCoまたはFeとRとの金属間化
合物相に一部R2(FeCo)14B相等を含みかつ希土
類含有量が多く、極力有機バインダーとの反応を抑える
ように主相系合金より平均粒径の大きい平均粒径8〜4
0μmの液相系化合物粉末の2種類の原料粉末を用いる
ことにより、焼結後の残留酸素量を低減できる。
Further, in order to suppress the reaction of the R component with the binder and water in the R—Fe—B-based magnetic powder, the R-Fe—B-based magnetic powder of the required single composition generally used in the conventional powder metallurgy method is used. R 2 Fe 14 B instead of Fe—B alloy raw material powder
Main phase-based alloy powder having an average particle diameter of 1 to 10 μm having a main phase, and an intermetallic compound phase of Co or Fe and R including an R 3 Co phase partially including an R 2 (FeCo) 14 B phase and the like In addition, the rare earth content is large, and the average particle diameter is larger than that of the main phase alloy so as to minimize the reaction with the organic binder.
By using two kinds of raw material powders of a liquid phase compound powder of 0 μm, the amount of residual oxygen after sintering can be reduced.

【0052】[0052]

【実施例】【Example】

実施例1 Rとして、Nd13.3原子%、Pr0.31原子%、
Dy0.28原子%、Co3.4原子%、B6.5原子
%、残部Fe及び不可避的不純物からなる原料を、Ar
ガス雰囲気中で高周波溶解して、ボタン状溶製合金を得
た。次に、該合金を粗粉砕した後、ジョークラッシャー
などにより平均粒度約15μmに粉砕し、さらに、ジェ
ットミルにより平均粒度3μmの粉末を得た。
Example 1 As R, 13.3 atomic% of Nd, 0.31 atomic% of Pr,
A raw material consisting of 0.28 atomic% of Dy, 3.4 atomic% of Co, 6.5 atomic% of B, balance Fe and inevitable impurities
High frequency melting was performed in a gas atmosphere to obtain a button-shaped ingot alloy. Next, after roughly pulverizing the alloy, it was pulverized with a jaw crusher or the like to an average particle size of about 15 μm, and further, a powder having an average particle size of 3 μm was obtained by a jet mill.

【0053】得られたR−Fe−B系合金粉末に表1に
示す添加量のステアリン酸亜鉛を添加して撹拌混練した
後、該粉末を流動造粒装置のチャンバー内に入れ、1%
濃度のセルロースエーテルあるいは2%濃度のポリビニ
ールアルコールを噴霧添加しながら、流動粉体層をN2
ガスとして撹拌羽根で20分間流動させた後、造粒粉を
乾燥するために、100℃のN2ガスをチャンバー底か
ら5分間噴出させ、乾燥して造粒粉を作製した。得られ
た造粒粉の平均粒度を表2に示す。
After adding the amount of zinc stearate shown in Table 1 to the obtained R-Fe-B-based alloy powder and kneading with stirring, the powder was placed in a chamber of a fluidized-granulation apparatus, and 1%
While adding sprayed polyvinyl alcohol cellulose ether or a concentration of 2% concentration, the fluidized powder layer N 2
After flowing as a gas with a stirring blade for 20 minutes, N 2 gas at 100 ° C. was blown out from the bottom of the chamber for 5 minutes to dry the granulated powder, followed by drying to produce a granulated powder. Table 2 shows the average particle size of the obtained granulated powder.

【0054】上記造粒粉を圧縮磁場プレス機を用いて、
磁場強度15kOe、圧力1ton/cm2で10mm
×15mm×厚み10mmの形状に成形した後、水素雰
囲気中で室温から300℃までを昇温速度100℃/時
で加熱する脱バインダー処理を行ない、引き続いて真空
中で1100℃まで昇温し1時間保持する焼結を行な
い、さらに焼結完了後、Arガスを導入して7℃/分の
速度で800℃まで冷却し、その後100℃/時の速度
で冷却して550℃で2時間保持して時効処理を施して
異方性の焼結体を得た。得られた全ての焼結体には、ワ
レ、ヒビ、変形などは全く見られなかった。
The above granulated powder was compressed using a compression magnetic field press.
Magnetic field strength 15 kOe, pressure 1 ton / cm 2 at 10 mm
After being formed into a shape of × 15 mm × 10 mm in thickness, a debinding treatment in which the temperature is increased from room temperature to 300 ° C. at a heating rate of 100 ° C./hour in a hydrogen atmosphere is performed. Sintering is performed for a period of time, and after completion of sintering, Ar gas is introduced and cooled at a rate of 7 ° C./min to 800 ° C., and then cooled at a rate of 100 ° C./hour and maintained at 550 ° C. for 2 hours. Then, aging treatment was performed to obtain an anisotropic sintered body. No cracks, cracks, deformations, or the like were found in any of the obtained sintered bodies.

【0055】成形時の造粒粉の流動性並びに得られた焼
結磁石の残留酸素量、残留炭素量、抗折強度、磁気特性
を表2に示す。なお、磁気特性の保磁力の目標値は14
(k0e)以上である。また、流動性は、内径5mmの
ロートの管を100gの原料粉が自然落下し通過するま
でに要した時間で測定した。さらに、抗折強度は30×
5×5mmの試料をスパーン20mmで5mmの厚み方
向に応力かけた測定値であり、目標値は200(MP
a)以上である。
Table 2 shows the fluidity of the granulated powder during molding, and the residual oxygen content, residual carbon content, bending strength and magnetic properties of the obtained sintered magnet. The target value of the coercive force of the magnetic characteristics is 14
(K0e) or more. The fluidity was measured by the time required for 100 g of the raw material powder to fall and pass through a funnel tube having an inner diameter of 5 mm. Furthermore, the bending strength is 30 ×
This is a measurement value obtained by applying a stress to a 5 × 5 mm sample in the thickness direction of 5 mm with a span of 20 mm, and the target value is 200 (MP
a) That is all.

【0056】[0056]

【表1】 [Table 1]

【0057】[0057]

【表2】 [Table 2]

【0058】実施例2 Sm11.9at%、Cu8.8at%、Fe12.6
at%、Zr1.2at%、残部Co及び不可避的不純
物からなる原料を、Arガス雰囲気中で高周波溶解し
て、ボタン状溶製合金を得た。次に、該合金を粗粉砕し
た後、ジョークラッシャーなどにより平均粒度約15μ
mに粉砕し、さらにジェットミルにより平均粒度3μm
の粉末を得た。
Example 2 Sm 11.9 at%, Cu 8.8 at%, Fe 12.6
A raw material comprising at%, Zr1.2 at%, balance Co and unavoidable impurities was subjected to high frequency melting in an Ar gas atmosphere to obtain a button-shaped ingot alloy. Next, after coarsely pulverizing the alloy, the average particle size is about 15 μm with a jaw crusher or the like.
m, and average particle size 3 μm by jet mill
Was obtained.

【0059】得られたSm−Co系合金粉末に表3に示
す添加量のステアリン酸亜鉛を添加して撹拌混練した
後、該粉末を流動造粒装置のチャンバー内に入れ、1%
濃度のセルロースエーテルあるいは2%濃度のポリビニ
ールアルコールを噴霧添加しながら、流動粉体層をN2
ガスとして撹拌羽根で20分間流動させた後、造粒粉を
乾燥するために、100℃のN2ガスをチャンバー底か
ら5分間噴出させ、乾燥して造粒粉を作製した。得られ
た造粒粉の平均粒度を表3に示す。
After adding the amount of zinc stearate shown in Table 3 to the obtained Sm-Co alloy powder and stirring and kneading, the powder was placed in a chamber of a fluidized-granulation apparatus, and 1%
While adding sprayed polyvinyl alcohol cellulose ether or a concentration of 2% concentration, the fluidized powder layer N 2
After flowing as a gas with a stirring blade for 20 minutes, N 2 gas at 100 ° C. was blown out from the bottom of the chamber for 5 minutes to dry the granulated powder, followed by drying to produce a granulated powder. Table 3 shows the average particle size of the obtained granulated powder.

【0060】該造粒粉を圧縮磁場プレス機を用いて、磁
場強度15kOe、圧力1ton/cm2で10mm×
15mm×厚み10mmの形状に成形した後、水素雰囲
気中で室温から300℃までを昇温速度100℃/時で
加熱する脱バインダー処理を行ない、引き続いて真空中
で1200℃まで昇温し1時間保持する焼結を行ない、
さらに焼結完了後、1160℃にて溶体化処理を施し、
Arガスを導入して800℃から400℃まで多段時効
処理を施した。
The granulated powder was subjected to a compression magnetic field press at a magnetic field strength of 15 kOe and a pressure of 1 ton / cm 2 at 10 mm ×
After being formed into a shape of 15 mm × 10 mm in thickness, debinding treatment is performed in a hydrogen atmosphere from room temperature to 300 ° C. at a heating rate of 100 ° C./hour, followed by heating to 1200 ° C. in vacuum for 1 hour Perform sintering to hold,
After completion of sintering, a solution treatment is performed at 1160 ° C.
A multi-stage aging treatment was performed from 800 ° C. to 400 ° C. by introducing Ar gas.

【0061】実施例1と同様に、成形時の造粒粉の流動
性、得られた焼結磁石の残留酸素量、残留炭素量、抗折
強度磁気特性を測定し、その結果を表4に示す。なお、
磁気特性の保磁力の目標値は9(kOe)以上である。
また、得られた全ての焼結体には、ワレ、ヒビ、変形な
どは全く見られなかった。
In the same manner as in Example 1, the fluidity of the granulated powder during molding, the residual oxygen content, the residual carbon content, and the bending strength magnetic properties of the obtained sintered magnet were measured. The results are shown in Table 4. Show. In addition,
The target value of the coercive force of the magnetic characteristics is 9 (kOe) or more.
In addition, cracks, cracks, deformation, and the like were not found in any of the obtained sintered bodies.

【0062】[0062]

【表3】 [Table 3]

【0063】[0063]

【表4】 [Table 4]

【0064】上記の結果より希土類含有合金粉末へのス
テアリン酸亜鉛の添加量を0.01wt%以上にすると
造粒後の粉体の流動性が著しく向上するとともに、磁気
特性の保磁力も著しく向上する効果がある。しかし、そ
の添加量が0.20wt%を超えると焼結体の抗折強度
が低下するために、その添加量は、0.01wt%〜
0.20wt%が好ましいことがわかる。
From the above results, when the amount of zinc stearate added to the rare earth-containing alloy powder is set to 0.01 wt% or more, the fluidity of the granulated powder is remarkably improved, and the coercive force of the magnetic properties is also remarkably improved. Has the effect of doing However, if the addition amount exceeds 0.20 wt%, the transverse rupture strength of the sintered body is reduced.
It turns out that 0.20 wt% is preferable.

【0065】[0065]

【発明の効果】この発明による希土類焼結永久磁石の製
造方法は、R−Fe−B系合金やR−Co系合金などの
希土類合金粉末に、例えば、ステアリン酸亜鉛にて疎水
処理した後、流動造粒装置のチャンバー内で水溶性ポリ
マーと水とからなるバインダーを噴霧添加しながら造粒
し、熱風ガスと撹拌羽根で撹拌、乾燥して、造粒粉とな
すことにより、圧縮成形前の給粉時及び圧縮成形時の粉
体の流動性、潤滑性を向上させて、成形サイクルの向
上、成形体の寸法精度を向上させ、また予め疎水処理し
てバインダー中の水との酸化反応を抑制したことによ
り、実施例に明らかなように、磁気特性の優れた焼結磁
石を安定的に効率よく製造することができる。
The method for manufacturing a rare earth sintered permanent magnet according to the present invention is a method for producing a rare earth alloy powder such as an R-Fe-B alloy or an R-Co alloy by subjecting a rare earth alloy powder to hydrophobic treatment with, for example, zinc stearate. In a fluidized-granulation apparatus chamber, granulation is performed while spray-adding a binder composed of a water-soluble polymer and water, and the mixture is stirred and dried with hot air gas and a stirring blade to form granulated powder. Improves the fluidity and lubricity of powder during powder feeding and compression molding, improves the molding cycle, improves the dimensional accuracy of the molded body, and preliminarily performs hydrophobic treatment to prevent oxidation reaction with water in the binder. As a result, it is possible to stably and efficiently manufacture a sintered magnet having excellent magnetic properties, as apparent from the examples.

【図面の簡単な説明】[Brief description of the drawings]

【図1】この発明に用いる流動造粒装置の構成を示す概
略説明図である。
FIG. 1 is a schematic explanatory view showing the configuration of a fluidized-granulation apparatus used in the present invention.

【符号の説明】[Explanation of symbols]

1 流動層チャンバー 2 撹拌羽根 3 熱風用ヒーター 4 入口ガス温度制御 5 噴射口 6 スプレー用ノズル 7 バグフィルター 8 導出口 DESCRIPTION OF SYMBOLS 1 Fluidized-bed chamber 2 Stirrer blade 3 Heater for hot air 4 Inlet gas temperature control 5 Injection port 6 Spray nozzle 7 Bag filter 8 Outlet

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】 有機金属化合物にて疎水処理した希土類
含有合金粉末を流動造粒装置に装入し、水溶性ポリマー
と水とからなるバインダーを噴霧添加しながら、該合金
粉末を熱風ガスと撹拌羽根で撹拌、乾燥することにより
造粒粉となし、該造粒粉を用いて磁場中で圧縮成形した
後、焼結する粉末冶金法により焼結永久磁石を製造する
希土類焼結永久磁石の製造方法。
1. A rare earth-containing alloy powder which has been subjected to a hydrophobic treatment with an organometallic compound is charged into a fluidized-bed granulator, and the alloy powder is stirred with hot air gas while a binder comprising a water-soluble polymer and water is added by spraying. Agitation and drying with blades to form granulated powder, compression molding in a magnetic field using the granulated powder, and sintering to produce sintered permanent magnet by powder metallurgy Manufacturing of rare earth sintered permanent magnet Method.
JP20303496A 1996-07-12 1996-07-12 Method for producing rare earth sintered permanent magnet Expired - Lifetime JP3631330B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP20303496A JP3631330B2 (en) 1996-07-12 1996-07-12 Method for producing rare earth sintered permanent magnet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP20303496A JP3631330B2 (en) 1996-07-12 1996-07-12 Method for producing rare earth sintered permanent magnet

Publications (2)

Publication Number Publication Date
JPH1032133A true JPH1032133A (en) 1998-02-03
JP3631330B2 JP3631330B2 (en) 2005-03-23

Family

ID=16467261

Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Status (1)

Country Link
JP (1) JP3631330B2 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000016937A1 (en) * 1998-09-24 2000-03-30 Sumitomo Electric Industries, Ltd. Alloy powder, alloy sintered compact and method for their production
JP2016143817A (en) * 2015-02-04 2016-08-08 Tdk株式会社 R-t-b-based sintered magnet
JP2022042969A (en) * 2020-09-03 2022-03-15 煙台東星磁性材料株式有限公司 Atomizing device and atomizing method of additives to neodymium-iron-boron-based alloy powder

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000016937A1 (en) * 1998-09-24 2000-03-30 Sumitomo Electric Industries, Ltd. Alloy powder, alloy sintered compact and method for their production
JP2016143817A (en) * 2015-02-04 2016-08-08 Tdk株式会社 R-t-b-based sintered magnet
JP2022042969A (en) * 2020-09-03 2022-03-15 煙台東星磁性材料株式有限公司 Atomizing device and atomizing method of additives to neodymium-iron-boron-based alloy powder
US11986836B2 (en) 2020-09-03 2024-05-21 Yantai Dongxing Magnetic Materials Inc. Device and method for the addition of liquid additives in the form of a spray during a jet milling step in a process for the manufacture of sintered NdFeB alloy magnets

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