JP3459477B2 - Production method of raw material powder for rare earth magnet - Google Patents
Production method of raw material powder for rare earth magnetInfo
- Publication number
- JP3459477B2 JP3459477B2 JP27061994A JP27061994A JP3459477B2 JP 3459477 B2 JP3459477 B2 JP 3459477B2 JP 27061994 A JP27061994 A JP 27061994A JP 27061994 A JP27061994 A JP 27061994A JP 3459477 B2 JP3459477 B2 JP 3459477B2
- Authority
- JP
- Japan
- Prior art keywords
- powder
- raw material
- rare earth
- atomic
- material powder
- 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.)
- Expired - Lifetime
Links
Classifications
-
- 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
- H01F1/0571—Alloys 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
- H01F1/0575—Alloys 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 pressed, sintered or bonded together
- H01F1/0576—Alloys 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 pressed, sintered or bonded together pressed, e.g. hot working
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】この発明は、Ｆｅ−Ｂ−Ｒ系希土
類磁石用原料粉末の微粉砕方法に係り、所要組成の粗粉
砕粉に特定の液状潤滑剤を混合してジェットミル粉砕
し、粉砕能率を向上させると共にプレス充填性にすぐ
れ、しかも配向性にすぐれた原料粉末を得る製造方法に
関する。
【０００２】
【従来の技術】一般に、Ｆｅ−Ｂ−Ｒ系希土類磁石用原
料粉末は、通常、下記１）〜２）工程あるいは１）ａ〜
２）ｂ工程により製造される。
１）出発原料として、希土類金属、電解鉄、フェロボロ
ン合金あるいはさらに電解Ｃｏを高周波溶解して鋳塊を
製造する。
２）鋳塊をＨ2吸蔵粉砕法により粗粉砕後、ボールミル
アトライターによる湿式粉砕してあるいは不活性ガス
によるジェットミル粉砕して、１．５μｍ〜５μｍ の
微細粉原料とする。
【０００３】１）ａ 希土類酸化物のうち少なくとも１
種、鉄粉及び純ボロン粉、フェロボロン粉及び硼素酸化
物のうち少なくとも１種、あるいは上記構成元素の合金
粉のまたは混合酸化物を所要組成に配合した混合粉に、
金属Ｃａ及びＣａＣｌ2を混合して、不活性ガス雰囲気
中にて、還元拡散を行なって得られた反応生成物をスラ
リー化し、水処理する。
２）ｂ 前記処理物をボールミル アトライターによる
湿式粉砕、あるいはジェットミルによる乾式粉砕によ
り、１．５μｍ〜５μｍの微粉砕粉にし、原料粉末とす
る。
【０００４】前記の如く、希土類磁石用原料粉末の微粉
砕は湿式粉砕にて行われており、例えば、アトライター
等の容器内に有機溶媒とともに原料粉末が投入されて微
粉砕するが、得られる微粉砕粉には有機溶媒によりＣ、
Ｏ2が含有され、また、ボールの摩耗による異物の混入
等の問題を生ずるため、乾式粉砕法へと移行しつつあ
る。
【０００５】
【発明が解決しようとする課題】しかし、乾式粉砕であ
るジェットミルによる微粉砕においては、ジェットミル
流を発生させる気体に、微粉砕粉の酸化防止ならびに発
火燃焼防止のため、純度９５％以上のＮ2ガス、または
Ａｒガスが使用されており、アトライター微粉砕法等の
湿式粉砕法に比し、粉砕効率が悪く、成型性も悪い問題
があった。
【０００６】従来の乾式粉砕法の問題点を解決するため
に、ジェットミル粉砕前に粗粉砕粉にステアリン酸亜
鉛、ステアリン酸カルシウムなどステアリン酸系固体潤
滑剤を添加混合後、ジェットミル粉砕するか、あるいは
ジェットミル粉砕後の微粉砕粉に前記ステアリン酸系固
体潤滑剤を添加混合後、成形する方法が試みられている
が、希土類磁石用原料合金の微粉末に前記固体潤滑剤を
均一に混合することは極めて困難であり、また、プレス
成形時に単重バラツキを発生したり、割れなど不良の原
因となっていた。
【０００７】この発明は、Ｆｅ−Ｂ−Ｒ系希土類磁石用
原料粉末の微粉砕方法において、特に、ジェットミル粉
砕における粉砕能率を大きく向上させると共にプレス充
填性にすぐれ、かつすぐれた配向性を有する磁石用原料
粉末の微粉砕方法の提供を目的としている。
【０００８】
【課題を解決するための手段】発明者は、Ｆｅ−Ｂ−Ｒ
系希土類磁石用原料粉末のジェットミル微粉砕法におい
て、微粉砕能率の向上と共にプレス充填性にすぐれ、プ
レス原料微粉末の磁界中プレス成型時、容易に磁界方向
に配向する微粉末のプレス原料粉末の製造法について種
々研究した結果、鋳塊粉砕法あるいはＣａ還元法により
得られた磁石組成の特定粒径の粗粉砕粉に特定の液状潤
滑剤を特定量添加して、ジェットミル粉砕することによ
り、微粉砕後の平均粒径１．５〜５．０μｍの微粉末の
粒子表面に均一に潤滑剤を被覆させることが可能とな
り、プレス原料粉末として所要の平均粒度を有する微粉
砕粉を得る能率が大幅に向上すると共に、粉末の流動性
が向上してプレス充填性が向上し、また、この発明によ
り得られた潤滑剤を表面に被覆した微粉砕粉は磁界中で
のプレス成型において、粉砕助剤の潤滑性により、微粉
砕粉の各粒子は磁界方向に容易に配向することにより、
すぐれた磁石特性を有する異方性焼結磁石が得られるこ
とを知見した。
【０００９】この発明は、Ｒ（Ｒは希土類元素の少なく
とも１種からなる）１０〜３０ａｔ％、Ｂ１〜２８ｗｔ
％、Ｆｅ４２〜８９ａｔ％（ただしＦｅの一部をＣｏに
て置換できる）を主成分とし、平均粒度１０μｍ〜５０
０μｍの希土類磁石用原料粉末の粗粉砕粉に、少なくと
も１種の脂肪酸エステルを石油系溶剤又はアルコール系
溶剤に５ｗｔ％〜５０ｗｔ％分散した液状潤滑剤を、
０．０２〜５．０ｗｔ％ 添加混合後、不活性ガスを用
いてジェットミル粉砕を行い、表面に前記潤滑剤が均一
被覆された平均粒度１．５μｍ〜５μｍの微粉末に微粉
砕することを特徴とする希土類磁石用原料粉末の製造方
法である。
【００１０】
【作用】この発明において、粗粉砕粉をジェットミルに
より微粉砕化するため添加する液状潤滑剤は、飽和ある
いは不飽和脂肪酸類エステル、並びに酸性塩としてほう
酸エステル等を石油系溶剤やアルコール系の溶剤に分散
させて用いる。液状潤滑剤中の脂肪酸エステル量は５ｗ
ｔ％〜５０ｗｔ％が好ましい。
【００１１】この発明の脂肪酸エステル系の潤滑剤とは
化学式 ＲＣＯＯＲ′ で示されるものである。上記化
学式において、Ｒは、ＣnＨ2n+2（アルカン） あるい
は、ＣnＨ2n（アルケン） ＣnＨ2n-2（アルキン）の
構造式で示されるものである。
【００１２】また、液状潤滑剤の添加量が、０．０２ｗ
ｔ％未満では、粉末粒子への被覆が十分でなく、プレス
充填性や配向性の改善が認められず、また、５ｗｔ％を
超えると、粉砕助剤中の不揮発残分が焼結体中に残存し
て、焼結密度の低下を生じ、磁石特性の劣化を招来する
ので好ましくない。
【００１３】この発明において、粗粉砕粉の平均粒度を
限定した理由は、平均粒度が１０μｍ未満では原料粉末
を大気中で安全に取扱うことが困難であり、原料粉末の
酸化により磁石特性が劣化するため好ましくなく、ま
た、５００μｍを超えるとジェットミル粉砕機への原料
供給が困難となり、粉砕能率を著しく低下するので好ま
しくない。
【００１４】この発明による微粉砕粉の平均粒度は、
１．５μｍ未満では粉末は極めて活性となり、プレス成
形などの工程において、発火する危険性があり、磁石特
性の劣化を生じ好ましくなく、また、５μｍを超える
と、焼結に得られる永久磁石の結晶粒が大きくなり、容
易に磁化反転が起こり、保磁力の低下を招来し好ましく
ないため、１．５μｍ〜５μｍの平均粒度とする。好ま
しい平均粒度は２．５μｍ〜４μｍである。
【００１５】以下にこの発明における、希土類磁石用粗
粉砕合金粉の組成限定理由を説明する。この発明の永久
磁石用粗粉砕合金粉に含有される希土類元素Ｒはイット
リウム（Ｙ）を包含し、軽希土類及び重希土類を包含す
る希土類元素である。Ｒとしては、軽希土類をもって足
り、特にＮｄ、Ｐｒが好ましい。また通例Ｒのうち１種
もって足りるが、実用上は２種以上の混合物（ミッシュ
メタル、ジジムなど）を入手上の便宜などの理由により
用いることができ、なお、このＲは純希土類元素でなく
てもよく、工業上入手可能な範囲で製造上不可避な不純
物を含有するもので差し支えない。Ｒは、Ｒ−Ｆｅ−Ｂ
系永久磁石を製造する合金粉末の必須元素であって、１
０原子％未満では高磁気特性、特に高保磁力が得られ
ず、３０原子％を超えると残留磁束密度（Ｂｒ）が低下
して、すぐれた特性の永久磁石が得られない。よって、
Ｒは１０原子％〜３０原子％の範囲とする。
【００１６】Ｂは、Ｒ−Ｆｅ−Ｂ系永久磁石を製造する
合金粉末の必須元素であって、１原子％未満では高い保
磁力（ｉＨｃ）は得られず、２８原子％を超えると残留
磁束密度（Ｂｒ）が低下するため、すぐれた永久磁石が
得られない。よって、Ｂは、１原子％〜２８原子％の範
囲とする。
【００１７】必須元素であるＦｅは、４２原子％未満で
は残留磁束密度（Ｂｒ）が低下し、８９％原子を超える
と高い保磁力が得られないので、Ｆｅは４２原子％〜８
９原子％に限定する。また、Ｆｅの一部をＣｏで置換す
る理由は、永久磁石の温度特性を向上させる効果及び耐
食性を向上させる効果が得られるためであるが、Ｃｏは
Ｆｅの５０％を超えると高い保磁力が得られず、すぐれ
た永久磁石が得られない。よって、ＣｏはＦｅの５０％
を上限とする。
【００１８】この発明の合金粉末において、高い残留磁
束密度と高い保磁力を共に有するすぐれた永久磁石を得
るためには、Ｒ１２原子％〜１６原子％、Ｂ４原子％〜
１２原子％、Ｆｅ７２原子％〜８４原子％が好ましい。
また、この発明による合金粉末は、Ｒ、Ｂ、Ｆｅの他、
工業的生産上不可避的不純物の存在を許容できるが、Ｂ
の一部を４．０原子％以下のＣ、３．５原子％以下の
Ｐ、２．５原子％以下のＳ、３．５原子％以下のＣｕの
うち少なくとも１種、合計量で４．０原子％以下で置換
することにより、磁石合金の製造性改善、低価格化が可
能である。
【００１９】さらに、前記Ｒ、Ｂ、Ｆｅ合金あるいはＣ
ｏを含有するＲ−Ｆｅ−Ｂ合金に、９．５原子％以下の
Ａｌ、４．５原子％以下のＴｉ、９．５原子％以下の
Ｖ、８．５原子％以下のＣｒ、８．０原子％以下のＭ
ｎ、５原子％以下のＢｉ、１２．５原子％以下のＮｂ、
１０．５原子％以下のＴａ、９．５原子％以下のＭｏ、
９．５原子％以下のＷ、２．５原子％以下のＳｂ、７原
子％以下のＧｅ、３．５原子％以下のＳｎ、５．５原子
％以下のＺｒ、５．５原子％以下のＨｆのうち少なくと
も１種添加含有させることにより、永久磁石合金の高保
磁力が可能になる。
【００２０】この発明のＲ−Ｆｅ−Ｂ系永久磁石におい
て、結晶相は主相が正方晶であることが不可欠であり、
特に、微細で均一な合金粉末を得て、すぐれた磁気特性
を有する焼結永久磁石を作成するのに効果的である。
【００２１】
【実施例】出発原料として、純度９９．９％の電解鉄、
Ｂ １９．８ｗｔ％含有のフェロボロン合金、純度９
９．７％以上のＮｄ，Ｄｙを使用し、これらを配合後高
周波溶解し、その後水冷銅鋳型に鋳造し、１４．５ａｔ
％Ｎｄ−０．５ａｔ％Ｄｙ−６．２ａｔ％Ｂ−７８．８
ａｔ％Ｆｅなる組成の鋳塊を得た。この後、前記鋳塊を
スタンプミルにより粗粉砕して、更に水素吸蔵による崩
壊などを行って平均粒度４０μｍの粗粉砕粉を得た。得
られた粗粉砕粉に表１の如く、液状潤滑剤として脂肪酸
エステル（品名 沸点１８０℃、有効成分２５ｗｔ％、
シクロヘキサン７５ｗｔ％）を添加配合し、ジェットミ
ルを使用し、不活性ガスＮ2ガスでガス圧７ｋｇ／ｍ2の
条件で微粉砕した。平均粒径約３μｍの微粉末を製造す
る場合の粉砕能率を表１に表す。
【００２２】得られた微粉砕粉をプレスの金型に装入
し、１０ｋＯｅの磁界中で配向し、磁界に直角方向に
１．５ｔｏｎ／ｃｍ2の圧力で成形して、１５ｍｍ×２
０ｍｍ×８ｍｍ寸法の成型体を得た。得られた成型体を
１１００℃×４時間、Ａｒ雰囲気中の条件にて焼結し、
さらに、Ａｒ雰囲気中で６００℃×１時間の時効処理を
行なった。得られた試験片の磁気特性を測定し、その結
果を表２に示す。なお、表１の比較例（Ｎｏ．６）は、
実施例１と同一の粗粉砕粉に潤滑剤としてステアリン酸
亜鉛を添加する以外は実施例１と同一の微粉砕条件、同
一製造条件にて得られた試験片であり、その磁石特性を
表２に示す。また、比較例（Ｎｏ．７）は実施例１と同
一の粗粉砕粉に潤滑剤を添加しない以外は実施例１と同
一の微粉砕条件、同一製造条件にて得られた試験片の磁
石特性を表２に示す。
【００２３】
【表１】【００２４】
【表２】
【００２５】
【発明の効果】この発明は、Ｒ−Ｂ−Ｆｅ系希土類磁石
用原料粉末の平均粒度１０μｍ〜５００μｍの粗粉砕粉
に脂肪酸エステルを液状化した潤滑剤を所定量 添加混
合後、不活性ガスを用いたジェットミル粉砕を行って、
平均粒度１．５μｍ〜５μｍの微粉末に微粉砕すること
を特徴とし、微粉砕後の微粉末粒子の表面に均一に潤滑
剤を被覆させることが可能となり、プレス原料粉末とし
て所要の平均粒度を有する微粉砕粉を得る能率が大幅に
向上する効果が得られ、また、粉末の流動性が向上して
プレス充填性が大きく向上する。さらに、この発明は、
得られた微粉砕粉は表面に粉砕助剤を均一に被覆してい
ることから、磁界中でのプレス成型において、当該粉砕
助剤の潤滑性により、微粉砕粉の各粒子は磁界方向に容
易に配向し、すぐれた磁石特性を有する異方性焼結磁石
が得られる利点がある。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for finely pulverizing a raw material powder for an Fe--BR--Rare earth magnet, and a liquid lubricating method specific to a coarsely pulverized powder having a required composition. The present invention relates to a method for producing a raw material powder which is mixed with an agent and jet mill-pulverized to improve the pulverizing efficiency, to have excellent press filling properties, and to have excellent orientation. 2. Description of the Related Art In general, raw material powders for Fe-BR based rare earth magnets are usually prepared in the following steps 1) to 2) or 1) a to 1).
2) It is manufactured by the step b. 1) As a starting material, a rare earth metal, electrolytic iron, ferroboron alloy or electrolytic Co is melted by high frequency to produce an ingot. 2) After roughly pulverizing the ingot by the H 2 occlusion pulverization method,
Wet pulverization with an attritor or jet mill pulverization with an inert gas is used to obtain a raw material of fine powder of 1.5 μm to 5 μm. 1) a At least one of the rare earth oxides
Seed, iron powder and pure boron powder, at least one of ferroboron powder and boron oxide, or an alloy powder of the above constituent elements or a mixed powder prepared by mixing a mixed oxide with a required composition,
The metal Ca and CaCl 2 are mixed, and the reaction product obtained by performing reduction diffusion in an inert gas atmosphere is slurried and treated with water. 2) b The processed material is pulverized into a fine powder of 1.5 μm to 5 μm by wet pulverization using a ball mill attritor or dry pulverization using a jet mill to obtain a raw material powder. As described above, the fine pulverization of the raw material powder for the rare earth magnet is performed by wet pulverization. For example, the raw material powder is charged together with an organic solvent into a vessel such as an attritor and finely pulverized. The finely pulverized powder is C,
Since it contains O 2 and causes problems such as mixing of foreign substances due to abrasion of balls, it is shifting to a dry pulverization method. [0005] However, in the case of fine pulverization by a jet mill which is dry pulverization, a gas which generates a jet mill flow has a purity of 95 to prevent oxidation of the finely pulverized powder and ignition and combustion. % Or more of N 2 gas or Ar gas is used, and there is a problem that the pulverization efficiency is poor and the moldability is poor as compared with a wet pulverization method such as an attritor pulverization method. [0006] In order to solve the problems of the conventional dry pulverization method, a solid stearic acid lubricant such as zinc stearate and calcium stearate is added to the coarsely pulverized powder before the jet mill pulverization and then mixed, followed by jet mill pulverization. Alternatively, a method of adding and mixing the stearic acid-based solid lubricant to the finely pulverized powder after jet mill pulverization and then shaping the mixture has been attempted, but the solid lubricant is uniformly mixed with the fine powder of the raw alloy for the rare earth magnet. This is extremely difficult, and has caused a single weight variation at the time of press molding and causes defects such as cracks. The present invention relates to a method of finely pulverizing a raw material powder for a Fe-BR based rare earth magnet, particularly to greatly improve the pulverizing efficiency in jet mill pulverization, to have excellent press filling properties, and to have excellent orientation. It aims to provide a method for finely pulverizing raw material powder for magnets. Means for Solving the Problems The present inventors have proposed Fe—BR
In the jet mill pulverization of raw material powders for rare earth magnets, the press raw material powder has excellent press-filling properties with improved pulverization efficiency, and is easily oriented in the direction of the magnetic field when press-formed in the magnetic field. As a result of various studies on the production method of the magnet, a specific amount of a specific liquid lubricant was added to a coarsely pulverized powder having a specific particle diameter of a magnet composition obtained by an ingot pulverization method or a Ca reduction method, and then jet-milled. It is possible to evenly coat the surface of the fine powder having an average particle size of 1.5 to 5.0 μm with the lubricant after the pulverization, and to obtain a finely pulverized powder having a required average particle size as a press raw material powder. Is greatly improved, the fluidity of the powder is improved, and the press-filling property is improved. Further, the finely pulverized powder coated on the surface with the lubricant obtained by the present invention can be used for press molding in a magnetic field. By lubricating the grinding aid, each particle of the finely pulverized powder by easily oriented in the direction of the magnetic field,
It has been found that an anisotropic sintered magnet having excellent magnet properties can be obtained. According to the present invention, R (R is at least one kind of rare earth element) 10 to 30 at%, B 1 to 28 wt%
%, Fe 42 to 89 at% (Fe can be partially replaced by Co) as a main component, and an average particle size of 10 μm to 50%.
At least one fatty acid ester is added to a roughly pulverized powder of a raw material powder for a rare earth magnet of 0 μm in a petroleum solvent or an alcohol solvent.
A liquid lubricant dispersed in a solvent in an amount of 5 wt% to 50 wt% ,
After adding and mixing 0.02 to 5.0 wt%, the mixture is pulverized by a jet mill using an inert gas, and the lubricant is uniformly applied to the surface.
A method for producing a raw material powder for a rare earth magnet, which comprises pulverizing into a fine powder having a coated average particle size of 1.5 μm to 5 μm. In the present invention, the liquid lubricant to be added for finely pulverizing the coarsely pulverized powder with a jet mill is a saturated or unsaturated fatty acid ester, or a boric acid ester or the like as an acid salt in a petroleum solvent or alcohol. Used by dispersing in a system solvent. The amount of fatty acid ester in the liquid lubricant is 5w
t% to 50 wt% is preferred. The fatty acid ester lubricant of the present invention is represented by the chemical formula RCOOR '. In the above formula, R represents, or C n H 2n + 2 (alkane), those represented by the structural formula C n H 2n (alkene) C n H 2n-2 (alkyne). The amount of the liquid lubricant added is 0.02 watts.
If the amount is less than t%, the coating on the powder particles is not sufficient, and no improvement in the press-filling property and orientation is observed. If the amount exceeds 5% by weight, the non-volatile residue in the pulverization aid is contained in the sintered body. It is not preferable because it remains and lowers the sintered density, leading to deterioration of the magnet characteristics. In the present invention, the reason why the average particle size of the coarsely pulverized powder is limited is that if the average particle size is less than 10 μm, it is difficult to handle the raw material powder safely in the atmosphere, and the magnet characteristics deteriorate due to oxidation of the raw material powder. If the thickness exceeds 500 μm, it is not preferable because it becomes difficult to supply the raw materials to the jet mill pulverizer, and the pulverization efficiency is significantly reduced. The average particle size of the finely pulverized powder according to the present invention is:
If the particle size is less than 1.5 μm, the powder becomes extremely active, and there is a risk of ignition in a process such as press molding, causing deterioration of magnet properties. This is undesirable, and if it exceeds 5 μm, the crystal of the permanent magnet obtained by sintering is obtained. Since the size of the grains becomes large, magnetization reversal easily occurs, and the coercive force is lowered, which is not preferable. Preferred average particle size is from 2.5 μm to 4 μm. The reasons for limiting the composition of the coarsely pulverized alloy powder for rare earth magnets in the present invention will be described below. The rare earth element R contained in the coarsely crushed alloy powder for a permanent magnet of the present invention is a rare earth element containing yttrium (Y) and including light rare earths and heavy rare earths. As R, a light rare earth element is sufficient, and Nd and Pr are particularly preferable. Usually, one kind of R is sufficient, but in practice, a mixture of two or more kinds (mish metal, dymium, etc.) can be used for reasons such as convenience in obtaining, and R is not a pure rare earth element. It may contain impurities which are unavoidable in production as far as it is industrially available. R is R-Fe-B
Essential element of the alloy powder for producing the permanent magnet
If it is less than 0 at%, high magnetic properties, particularly high coercive force, cannot be obtained. If it exceeds 30 at%, the residual magnetic flux density (Br) is reduced, and a permanent magnet having excellent properties cannot be obtained . I'm,
R is in the range of 10 at% to 30 at%. B is an essential element of the alloy powder for producing the R—Fe—B permanent magnet. If it is less than 1 atomic%, a high coercive force (iHc) cannot be obtained. Since the density (Br) decreases, an excellent permanent magnet cannot be obtained. Therefore, B is set in the range of 1 to 28 atomic%. Fe, which is an essential element, has a residual magnetic flux density (Br) lower than 42 atomic%, and a high coercive force cannot be obtained if it exceeds 89 atomic%.
Limited to 9 atomic%. The reason why part of Fe is replaced by Co is that the effect of improving the temperature characteristics of the permanent magnet and the effect of improving the corrosion resistance are obtained. However, when Co exceeds 50% of Fe, a high coercive force is obtained. No permanent magnet can be obtained. Therefore, Co is 50% of Fe
Is the upper limit. In order to obtain an excellent permanent magnet having both a high residual magnetic flux density and a high coercive force in the alloy powder of the present invention, R12 atomic% to 16 atomic%, B4 atomic%
It is preferably 12 atomic% and Fe 72 to 84 atomic%.
In addition, the alloy powder according to the present invention includes R, B, Fe,
The presence of unavoidable impurities in industrial production can be tolerated.
Of at least one of C of 4.0 atomic% or less, P of 3.5 atomic% or less, S of 2.5 atomic% or less, and Cu of 3.5 atomic% or less in a total amount of 4.0%. By substituting at 0 atomic% or less, the productivity of the magnet alloy can be improved and the price can be reduced. Further, the R, B, Fe alloy or C
In an R-Fe-B alloy containing o, 9.5 atomic% or less of Al, 4.5 atomic% or less of Ti, 9.5 atomic% or less of V, 8.5 atomic% or less of Cr, M of 0 atomic% or less
n, Bi at 5 atomic% or less, Nb at 12.5 atomic% or less,
10.5 atomic% or less of Ta, 9.5 atomic% or less of Mo,
9.5 atomic% or less W, 2.5 atomic% or less Sb, 7 atomic% or less Ge, 3.5 atomic% or less Sn, 5.5 atomic% or less Zr, 5.5 atomic% or less By adding and including at least one of Hf, a high coercive force of the permanent magnet alloy becomes possible. In the R—Fe—B permanent magnet of the present invention, it is essential that the main phase of the crystal phase is tetragonal.
In particular, it is effective for obtaining a fine and uniform alloy powder and producing a sintered permanent magnet having excellent magnetic properties. EXAMPLES As starting materials, electrolytic iron having a purity of 99.9% was used.
B Ferroboron alloy containing 19.8 wt%, purity 9
9.7% or more of Nd and Dy are used, and after mixing these, high-frequency melting is performed, and then cast into a water-cooled copper mold to obtain 14.5 at.
% Nd-0.5 at% Dy-6.2 at% B-78.8
An ingot having a composition of at% Fe was obtained. Thereafter, the ingot was coarsely pulverized by a stamp mill and further collapsed by hydrogen absorption to obtain a coarsely pulverized powder having an average particle size of 40 μm. As shown in Table 1, a fatty acid ester (product name: boiling point: 180 ° C., active ingredient: 25 wt%,
Cyclohexane (75 wt%) was added and blended, and finely pulverized with an inert gas N 2 gas at a gas pressure of 7 kg / m 2 using a jet mill. Table 1 shows the crushing efficiency when producing fine powder having an average particle size of about 3 μm. The obtained finely pulverized powder is charged into a press mold, oriented in a magnetic field of 10 kOe, and molded in a direction perpendicular to the magnetic field at a pressure of 1.5 ton / cm 2 to form a 15 mm × 2
A molded article having a size of 0 mm × 8 mm was obtained. The obtained molded body was sintered at 1100 ° C. for 4 hours under conditions in an Ar atmosphere,
Further, aging treatment was performed at 600 ° C. for 1 hour in an Ar atmosphere. The magnetic properties of the obtained test pieces were measured, and the results are shown in Table 2. In addition, the comparative example (No. 6) of Table 1 is:
The test pieces were obtained under the same finely pulverizing conditions and the same manufacturing conditions as in Example 1 except that zinc stearate was added as a lubricant to the same coarsely pulverized powder as in Example 1. Shown in In Comparative Example (No. 7), the magnet properties of the test pieces obtained under the same fine pulverization conditions and the same production conditions as in Example 1 except that no lubricant was added to the same coarsely pulverized powder as in Example 1 Are shown in Table 2. [Table 1] [Table 2] According to the present invention, a predetermined amount of a lubricant obtained by liquefying a fatty acid ester is added to coarsely ground powder having an average particle size of 10 μm to 500 μm of a raw material powder for an RB—Fe rare earth magnet, and then mixed. Performing jet mill pulverization using active gas,
It is characterized by being finely pulverized to a fine powder having an average particle size of 1.5 μm to 5 μm, and it is possible to uniformly coat the surface of the fine powder particles after the fine pulverization with a lubricant. The effect of greatly improving the efficiency of obtaining the finely pulverized powder is obtained, and the fluidity of the powder is improved, and the press filling property is greatly improved. In addition, the present invention
Since the obtained finely pulverized powder uniformly coats the pulverization aid on the surface, each particle of the finely pulverized powder is easily oriented in the direction of the magnetic field due to the lubricity of the pulverization aid in a press molding in a magnetic field. There is an advantage that an anisotropic sintered magnet having excellent magnet properties can be obtained.
フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｃ２２Ｃ 38/00 ３０３ Ｈ０１Ｆ 1/06 Ａ (56)参考文献 特開 平５−94922（ＪＰ，Ａ) 特開 平１−119603（ＪＰ，Ａ) 特開 平１−255602（ＪＰ，Ａ) 特開 平４−7804（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01F 1/00 - 1/117 B22F 1/00 - 8/00 B22F 9/00 - 9/30 C22C 33/02 C22C 38/00 303 C10M 101/00 - 177/00 Continuation of the front page (51) Int.Cl. 7 Identification symbol FI C22C 38/00 303 H01F 1/06 A (56) References JP-A-5-94922 (JP, A) JP-A-1-119603 (JP, A) JP-A-1-255602 (JP, A) JP-A-4-7804 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) H01F 1/00-1/117 B22F 1 / 00-8/00 B22F 9/00-9/30 C22C 33/02 C22C 38/00 303 C10M 101/00-177/00
Claims (1)
らなる）１０〜３０ａｔ％、Ｂ１〜２８ａｔ％、Ｆｅ４
２〜８９ａｔ％（ただしＦｅの１部をＣｏにて置換でき
る）を主成分とし、平均粒度１０μｍ〜５００μｍの希
土類磁石用原料粉末の粗粉砕粉に、少なくとも１種の脂
肪酸エステル少なくとも１種の脂肪酸エステルを石油系
溶剤又はアルコール系溶剤に５ｗｔ％〜５０ｗｔ％分散
した液状潤滑剤を、０．０２〜５．０ｗｔ％ 添加混合
後、不活性ガスを用いたジェットミル粉砕を行い、表面
に前記潤滑剤が均一被覆された平均粒度１．５μｍ〜５
μｍの微粉末に微粉砕することを特徴とする希土類磁石
用原料粉末の製造方法。(57) Claims 1. R (R is at least one of rare earth elements) 10 to 30 at%, B 1 to 28 at%, Fe4
At least one fatty acid ester and at least one fatty acid are added to coarsely pulverized raw material powder for a rare earth magnet having a main component of 2 to 89 at% (a part of Fe can be replaced by Co) and having an average particle size of 10 μm to 500 μm. Esters to petroleum
5wt% -50wt% dispersion in solvent or alcohol solvent
After adding and mixing 0.02 to 5.0 wt% of the obtained liquid lubricant, the mixture was subjected to jet mill pulverization using an inert gas to obtain a surface.
The average particle size of the lubricant is uniformly coated on 1.5μm~5
A method for producing a raw material powder for a rare earth magnet, which comprises pulverizing the raw material powder into a fine powder of μm.
Priority Applications (9)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27061994A JP3459477B2 (en) | 1994-10-07 | 1994-10-07 | Production method of raw material powder for rare earth magnet |
| US08/523,928 US5666635A (en) | 1994-10-07 | 1995-09-06 | Fabrication methods for R-Fe-B permanent magnets |
| TW084109510A TW290697B (en) | 1994-10-07 | 1995-09-12 | |
| AT95306507T ATE183016T1 (en) | 1994-10-07 | 1995-09-14 | METHOD FOR PRODUCING R-FE-B PERMANENT MAGNETS |
| EP95306507A EP0706190B1 (en) | 1994-10-07 | 1995-09-14 | Fabrication method for R-Fe-B permanent magnets |
| DE69511202T DE69511202T2 (en) | 1994-10-07 | 1995-09-14 | Process for the production of R-Fe-B permanent magnets |
| CN95117263A CN1120507C (en) | 1994-10-07 | 1995-10-05 | Method for producing R-Fe-B series permanent magnet |
| KR1019950034256A KR100202161B1 (en) | 1994-10-07 | 1995-10-06 | Fabrication methods for r-fe-b permanent magnets |
| RU95117066A RU2112627C1 (en) | 1994-10-07 | 1995-10-06 | PROCESS OF MANUFACTURE OF R-Fe-B PERMANENT MAGNETS |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27061994A JP3459477B2 (en) | 1994-10-07 | 1994-10-07 | Production method of raw material powder for rare earth magnet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08111308A JPH08111308A (en) | 1996-04-30 |
| JP3459477B2 true JP3459477B2 (en) | 2003-10-20 |
Family
ID=17488616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27061994A Expired - Lifetime JP3459477B2 (en) | 1994-10-07 | 1994-10-07 | Production method of raw material powder for rare earth magnet |
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| Country | Link |
|---|---|
| JP (1) | JP3459477B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2597660A2 (en) | 2004-07-01 | 2013-05-29 | Intermetallics Co., Ltd. | Method and system for manufacturing sintered rare-earth magnet having magnetic anisotropy |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1288679C (en) * | 1998-04-22 | 2006-12-06 | 株式会社新王磁材 | Method for producing R-Fe-B permanent magnet, and lubricating agent for use in shaping the same |
| CN104190944B (en) * | 2014-08-12 | 2016-04-13 | 宁波韵升股份有限公司 | A kind of preparation method of Sintered NdFeB magnet and device |
-
1994
- 1994-10-07 JP JP27061994A patent/JP3459477B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2597660A2 (en) | 2004-07-01 | 2013-05-29 | Intermetallics Co., Ltd. | Method and system for manufacturing sintered rare-earth magnet having magnetic anisotropy |
| EP2597659A2 (en) | 2004-07-01 | 2013-05-29 | Intermetallics Co., Ltd. | Method and system for manufacturing sintered rare-earth magnet having magnetic anisotropy |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08111308A (en) | 1996-04-30 |
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