JP2007288021A - PROCESS FOR PRODUCING R-Fe-B BASED RARE EARTH SINTERED MAGNET - Google Patents

PROCESS FOR PRODUCING R-Fe-B BASED RARE EARTH SINTERED MAGNET Download PDF

Info

Publication number
JP2007288021A
JP2007288021A JP2006115225A JP2006115225A JP2007288021A JP 2007288021 A JP2007288021 A JP 2007288021A JP 2006115225 A JP2006115225 A JP 2006115225A JP 2006115225 A JP2006115225 A JP 2006115225A JP 2007288021 A JP2007288021 A JP 2007288021A
Authority
JP
Japan
Prior art keywords
rare earth
sintered magnet
magnet body
earth sintered
molten salt
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
JP2006115225A
Other languages
Japanese (ja)
Other versions
JP4742966B2 (en
Inventor
Masayuki Yoshimura
吉村  公志
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.)
Proterial Ltd
Original Assignee
Hitachi Metals 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 Hitachi Metals Ltd filed Critical Hitachi Metals Ltd
Priority to JP2006115225A priority Critical patent/JP4742966B2/en
Publication of JP2007288021A publication Critical patent/JP2007288021A/en
Application granted granted Critical
Publication of JP4742966B2 publication Critical patent/JP4742966B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • 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
    • H01F1/0575Alloys 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
    • H01F1/0577Alloys 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 sintered
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/002Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/005Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/06Ferrous alloys, e.g. steel alloys containing aluminium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/10Ferrous alloys, e.g. steel alloys containing cobalt
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/16Ferrous alloys, e.g. steel alloys containing copper
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00Electroplating: Baths therefor
    • C25D3/02Electroplating: Baths therefor from solutions
    • C25D3/54Electroplating: Baths therefor from solutions of metals not provided for in groups C25D3/04 - C25D3/50
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00Electroplating: Baths therefor
    • C25D3/66Electroplating: Baths therefor from melts
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00Electroplating: Baths therefor
    • C25D3/66Electroplating: Baths therefor from melts
    • C25D3/665Electroplating: Baths therefor from melts from ionic liquids
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/48After-treatment of electroplated surfaces
    • C25D5/50After-treatment of electroplated surfaces by heat-treatment
    • 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
    • H01F41/0293Apparatus 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 diffusion of rare earth elements, e.g. Tb, Dy or Ho, into permanent magnets

Abstract

<P>PROBLEM TO BE SOLVED: To enhance coercive force while controlling fall of residual magnetic flux density by forming main phase crystal grains where Dy is condensed at the shell efficiently, even in an R-Fe-B based rare earth sintered magnet body. <P>SOLUTION: In the process for producing an R-Fe-B based rare earth sintered magnet, an R-Fe-B based rare earth sintered magnet body is prepared, and Dy is electrodeposited on the surface of the R-Fe-B based rare earth sintered magnet body by performing electrolysis in fused salt containing Dy ions. Thereafter, Dy is diffused into the R-Fe-B based rare earth sintered magnet body by heating it. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、R2Fe14B型化合物結晶粒(Rは希土類元素)を主相として有するR−Fe−B系希土類焼結磁石の製造方法に関し、特に、軽希土類元素RL(NdおよびPrの少なくとも1種)を主たる希土類元素Rとして含有し、かつ、軽希土類元素RLの一部がDyによって置換されているR−Fe−B系希土類焼結磁石の製造方法に関している。 The present invention relates to a method for producing an R—Fe—B rare earth sintered magnet having R 2 Fe 14 B type compound crystal grains (R is a rare earth element) as a main phase, and in particular, light rare earth elements RL (of Nd and Pr). The present invention relates to a method for producing an R—Fe—B rare earth sintered magnet which contains at least one kind) as a main rare earth element R, and a part of the light rare earth element RL is substituted by Dy.

Nd2Fe14B型化合物を主相とするR−Fe−B系の希土類焼結磁石は、永久磁石の中で最も高性能な磁石として知られており、ハードディスクドライブのボイスコイルモータ(VCM)や、ハイブリッド車搭載用モータ等の各種モータや家電製品等に使用されている。R−Fe−B系希土類焼結磁石をモータ等の各種装置に使用する場合、高温での使用環境に対応するため、耐熱性に優れ、高保磁力特性を有することが要求される。 R-Fe-B rare earth sintered magnets with Nd 2 Fe 14 B type compound as the main phase are known as the most powerful magnets among permanent magnets, and are voice coil motors (VCM) for hard disk drives. In addition, it is used in various motors such as motors for mounting on hybrid vehicles, and home appliances. When R-Fe-B rare earth sintered magnets are used in various devices such as motors, they are required to have excellent heat resistance and high coercive force characteristics in order to cope with high temperature use environments.

R−Fe−B系希土類焼結磁石の保磁力を向上する手段として、Dyを原料として配合し、溶製した合金を用いることが行われている。この方法によると、希土類元素Rとして軽希土類元素RLを含有するR2Fe14B相の希土類元素RがDyで置換されるため、R2Fe14B相の結晶磁気異方性(保磁力を決定する本質的な物理量)が向上する。しかし、R2Fe14B相中における軽希土類元素RLの磁気モーメントは、Feの磁気モーメントと同一方向であるのに対して、Dyの磁気モーメントは、Feの磁気モーメントと逆方向であるため、軽希土類元素RLをDyで置換するほど、残留磁束密度Brが低下してしまうことになる。 As a means for improving the coercive force of an R—Fe—B rare earth sintered magnet, an alloy prepared by melting Dy as a raw material is used. According to this method, since the rare earth element R in the R 2 Fe 14 B phase containing the light rare earth element RL as the rare earth element R is substituted with Dy, the magnetocrystalline anisotropy (coercivity of the R 2 Fe 14 B phase) The essential physical quantity to be determined) is improved. However, the magnetic moment of the light rare earth element RL in the R 2 Fe 14 B phase is in the same direction as the magnetic moment of Fe, whereas the magnetic moment of Dy is opposite to the magnetic moment of Fe. As the light rare earth element RL is replaced with Dy, the residual magnetic flux density Br decreases.

一方、Dyは希少資源であるため、その使用量の削減が望まれている。これらの理由により、軽希土類元素RLの全体をDyで置換する方法は好ましくない。   On the other hand, since Dy is a scarce resource, it is desired to reduce its usage. For these reasons, the method of replacing the entire light rare earth element RL with Dy is not preferable.

比較的少ない量のDyを添加することにより、Dyによる保磁力向上効果を発現させるため、Dyを多く含む合金・化合物などの粉末を、軽希土類RLを多く含む主相系母合金粉末に添加し、成形・焼結させることが提案されている。この方法によると、DyがR2Fe14B相の粒界近傍に多く分布することになるため、主相外殻部におけるR2Fe14B相の結晶磁気異方性を効率よく向上させることが可能になる。R−Fe−B系希土類焼結磁石の保磁力発生機構は核生成型(ニュークリエーション型)であるため、主相外殻部(粒界近傍)にDyが多く分布することにより、結晶粒全体の結晶磁気異方性が高められ、逆磁区の核生成が妨げられ、その結果、保磁力が向上する。また、保磁力向上に寄与しない結晶粒の中心部では、Dyによる置換が生じないため、残留磁束密度Brの低下を抑制することもできる。 In order to develop a coercive force improving effect by adding a relatively small amount of Dy, an alloy / compound powder containing a large amount of Dy is added to the main phase mother alloy powder containing a large amount of light rare earth RL. It has been proposed to form and sinter. According to this method, since Dy is to distributed more in the grain boundary vicinity of the R 2 Fe 14 B phase, to improve efficiently the magnetocrystalline anisotropy of the R 2 Fe 14 B phase in the outer periphery of the main phase Is possible. Since the coercive force generation mechanism of the R—Fe—B rare earth sintered magnet is a nucleation type (nucleation type), a large amount of Dy is distributed in the outer shell portion (near the grain boundary) of the main phase. The magnetocrystalline anisotropy is increased, and the nucleation of reverse magnetic domains is hindered. As a result, the coercive force is improved. Moreover, since substitution by Dy does not occur in the center part of the crystal grains that do not contribute to the improvement of the coercive force, it is possible to suppress a decrease in the residual magnetic flux density Br.

しかしながら、実際にこの方法を実施してみると、焼結工程(工業規模で1000℃から1200℃で実行される)でDyの拡散速度が大きくなるため、Dyが結晶粒の中心部にも拡散してしまう結果、期待していた組織構造を得ることは容易でない。   However, when this method is actually carried out, the diffusion rate of Dy increases in the sintering process (executed at 1000 ° C. to 1200 ° C. on an industrial scale), so that Dy also diffuses into the center of the crystal grains. As a result, it is not easy to obtain the expected organizational structure.

さらにR−Fe−B系希土類焼結磁石の別の保磁力向上手段として、焼結磁石の段階でDyを含む金属、合金、化合物等を磁石表面に被着後、熱処理、拡散させることによって、残留磁束密度をそれほど低下させずに保磁力を回復または向上させることが検討されている(特許文献1、特許文献2、及び特許文献3)。   Further, as another means for improving the coercive force of the R-Fe-B rare earth sintered magnet, after depositing a metal, alloy, compound, etc. containing Dy on the magnet surface at the stage of the sintered magnet, heat treatment and diffusion are performed. It has been studied to recover or improve the coercive force without significantly reducing the residual magnetic flux density (Patent Document 1, Patent Document 2, and Patent Document 3).

特許文献1は、Ti、W、Pt、Au、Cr、Ni、Cu、Co、Al、Ta、Agのうち少なくとも1種を1.0原子%〜50.0原子%含有し、残部R´(R´はCe、La、Nd、Pr、Dy、Ho、Tbのうち少なくとも1種)からなる合金薄膜層を焼結磁石体の被研削加工面に形成することを開示している。   Patent Document 1 contains 1.0 atomic% to 50.0 atomic% of at least one of Ti, W, Pt, Au, Cr, Ni, Cu, Co, Al, Ta, and Ag, and the balance R ′ ( R ′ discloses that an alloy thin film layer made of Ce, La, Nd, Pr, Dy, Ho, and Tb is formed on the ground surface of the sintered magnet body.

特許文献2は、小型磁石の最表面に露出している結晶粒子の半径に相当する深さ以上に金属元素R(このRは、Y及びNd、Dy、Pr、Ho、Tbから選ばれる希土類元素の1種又は2種以上)を拡散させ、それによって加工変質損傷部を改質して(BH)maxを向上させることを開示している。   Patent Document 2 states that a metal element R (the R is a rare earth element selected from Y and Nd, Dy, Pr, Ho, and Tb) exceeds the depth corresponding to the radius of the crystal grains exposed on the outermost surface of the small magnet. 1 type or two or more types) are diffused, thereby modifying the damaged part of the work and improving (BH) max.

特許文献3は、厚さ2mm以下の磁石の表面に希土類元素を主体とする化学気相成長膜を形成し、磁石特性を回復させることを開示している。   Patent Document 3 discloses that a chemical vapor deposition film mainly composed of rare earth elements is formed on the surface of a magnet having a thickness of 2 mm or less to recover the magnet characteristics.

一方、Dy層を焼結磁石表面に形成する他の方法として、ディッピング(溶融めっき)法が提案されている。特許文献4は、Dy−FeなどのDy合金の溶湯中に磁石を浸漬し、その後、時効処理を行うことを開示している。
特開昭62−192566号公報 特開2004−304038号公報 特開2005−285859号公報 特開2005−209932号公報
On the other hand, as another method for forming the Dy layer on the surface of the sintered magnet, a dipping (hot dip) method has been proposed. Patent Document 4 discloses that a magnet is immersed in a molten metal of Dy alloy such as Dy-Fe, and thereafter an aging treatment is performed.
JP-A-62-192566 JP 2004-304038 A JP 2005-285859 A JP 2005-209932 A

特許文献1、特許文献2及び特許文献3に開示されている従来技術は、いずれも、加工劣化した焼結磁石表面の回復を目的としているため、表面から内部に拡散される金属元素の拡散範囲は、焼結磁石の表面近傍に限られている。このため、厚さ3mm以上の磁石では、保磁力の向上効果がほとんど得られない。   The conventional techniques disclosed in Patent Document 1, Patent Document 2 and Patent Document 3 are all intended to recover the surface of a sintered magnet that has been deteriorated by processing. Is limited to the vicinity of the surface of the sintered magnet. For this reason, the effect of improving the coercive force is hardly obtained with a magnet having a thickness of 3 mm or more.

また、特許文献1から3の方法のいずれも、Dy層を焼結磁石体上に成長させる過程で、成膜装置内部の磁石以外の部分(例えば真空チャンバーの内壁)にも多量に希土類金属が堆積するため、貴重資源である重希土類元素の省資源化に反することになる。   In any of the methods of Patent Documents 1 to 3, a large amount of rare earth metal is also present in a portion other than the magnet inside the film forming apparatus (for example, the inner wall of the vacuum chamber) in the process of growing the Dy layer on the sintered magnet body. Since it accumulates, it is contrary to the resource saving of the heavy rare earth element which is a valuable resource.

これに対して、特許文献4に開示されている方法によれば、磁石以外の装置部分にDy金属が付着する量が少なく、原理的には高歩留まりが期待できる。しかしながら、Dyを溶融するにはDyの融点以上の温度に加熱する必要があり、そのような高温の溶湯中に希土類焼結磁石を浸すと、希土類焼結磁石の粒界相が溶け出してしまい、磁石特性が劣化する。このような問題を回避するには、Dy溶湯の温度を低下させる必要があるが、そのためには、Dy単体ではなくDy合金(例えばDy−Fe)を用いる必要がある。しかし、このような合金溶湯に希土類焼結磁石を浸すと、Dy以外の金属成分(例えばFe)を含有する合金層しか焼結磁石上に形成できない。このような合金層から焼結磁石中に拡散を行うと、Dy以外の金属成分の存在により、Dyの拡散効率が低下してしまう。   On the other hand, according to the method disclosed in Patent Document 4, the amount of Dy metal adhering to the device portion other than the magnet is small, and in principle, a high yield can be expected. However, in order to melt Dy, it is necessary to heat to a temperature equal to or higher than the melting point of Dy. When a rare earth sintered magnet is immersed in such a high temperature molten metal, the grain boundary phase of the rare earth sintered magnet is melted. , Magnet characteristics deteriorate. In order to avoid such a problem, it is necessary to lower the temperature of the molten Dy. To that end, it is necessary to use a Dy alloy (for example, Dy-Fe) instead of Dy alone. However, when a rare earth sintered magnet is immersed in such a molten alloy, only an alloy layer containing a metal component (for example, Fe) other than Dy can be formed on the sintered magnet. When diffusion is performed from such an alloy layer into the sintered magnet, the diffusion efficiency of Dy is reduced due to the presence of metal components other than Dy.

また、特許文献4に開示されているようなディッピング法では、希土類磁石の表面に形成される合金層の厚さを高精度に制御することが困難であり、必要以上に厚い膜が不均一に形成されてしまう。このため、ディッピング法に焼結磁石表面の厚膜合金を均一に薄膜化する表面研削加工が必要になり、製造コストが増加してしまう。   In addition, in the dipping method disclosed in Patent Document 4, it is difficult to control the thickness of the alloy layer formed on the surface of the rare earth magnet with high accuracy, and a film that is thicker than necessary is not uniform. Will be formed. For this reason, a surface grinding process for uniformly thinning the thick film alloy on the surface of the sintered magnet is required for the dipping method, which increases the manufacturing cost.

本発明は、上記課題を解決するためになされたものであり、その目的とするところは、製造コストを増加させることなく、少ない量のDyを効率よく焼結磁石体の内部に拡散させ、保磁力が向上したR−Fe−B系希土類焼結磁石の製造方法を提供することにある。   The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to efficiently diffuse and maintain a small amount of Dy inside the sintered magnet body without increasing the manufacturing cost. An object of the present invention is to provide a method for producing an R—Fe—B rare earth sintered magnet with improved magnetic force.

本発明によるR−Fe−B系希土類焼結磁石の製造方法は、軽希土類元素RL(NdおよびPrの少なくとも1種)を主たる希土類元素Rとして含有するR2Fe14B型化合物結晶粒を主相として有する少なくとも1つのR−Fe−B系希土類焼結磁石体を用意する工程(A)と、Dyイオンを含有する溶融塩中で電解を行うことにより、前記R−Fe−B系希土類焼結磁石体の表面にDyを電析させる工程(B)と、前記Dyが表面に電析したR−Fe−B系希土類焼結磁石体を加熱することにより、前記R−Fe−B系希土類焼結磁石体の内部にDyを拡散させる工程(C)とを包含する。 The method for producing an R—Fe—B rare earth sintered magnet according to the present invention mainly comprises R 2 Fe 14 B type compound crystal grains containing a light rare earth element RL (at least one of Nd and Pr) as a main rare earth element R. Step (A) of preparing at least one R—Fe—B rare earth sintered magnet body having a phase and electrolysis in a molten salt containing Dy ions Step (B) of depositing Dy on the surface of the magnetized body, and heating the R—Fe—B rare earth sintered magnet body on which the Dy is electrodeposited, thereby heating the R—Fe—B rare earth. And (D) diffusing Dy inside the sintered magnet body.

好ましい実施形態において、前記工程(B)において、前記溶融塩の温度を300℃以上600℃未満に設定した状態で電解を行う。   In preferable embodiment, in the said process (B), it electrolyzes in the state which set the temperature of the said molten salt to 300 to 600 degreeC.

好ましい実施形態において、前記工程(C)において、前記R−Fe−B系希土類焼結磁石体の加熱温度を700℃以上1000℃以下の範囲内に設定する。   In a preferred embodiment, in the step (C), the heating temperature of the R—Fe—B rare earth sintered magnet body is set in the range of 700 ° C. or more and 1000 ° C. or less.

好ましい実施形態において、前記工程(C)において、前記処理室内を真空または不活性雰囲気で満たした状態で加熱処理を行う。   In a preferred embodiment, in the step (C), heat treatment is performed in a state where the processing chamber is filled with a vacuum or an inert atmosphere.

好ましい実施形態において、前記溶融塩として、アルカリ金属ハライドまたはアルカリ土類金属ハライドを用いる。   In a preferred embodiment, an alkali metal halide or an alkaline earth metal halide is used as the molten salt.

好ましい実施形態において、前記溶融塩として、LiCl−KClまたはCsCl−LiClを用いる。   In a preferred embodiment, LiCl—KCl or CsCl—LiCl is used as the molten salt.

好ましい実施形態において、前記工程(B)において、1μm以上10μm以下の厚さを有するDy層を前記R−Fe−B系希土類焼結磁石体の表面に形成する。   In a preferred embodiment, in the step (B), a Dy layer having a thickness of 1 μm to 10 μm is formed on the surface of the R—Fe—B rare earth sintered magnet body.

本発明によれば、Dyイオンが溶けた溶融塩で電解を行うことにより、R−Fe−B系希土類焼結磁石体の表面にDyを電析させた後、焼結磁石体の内部にDyを拡散させる。このため、Dyを無駄に消費してしまうことなく、極めて効率的に磁石体の内部に拡散させることが可能になる。   According to the present invention, after electrolysis is performed with a molten salt in which Dy ions are dissolved, Dy is electrodeposited on the surface of the R—Fe—B rare earth sintered magnet body, and then the Dy is formed inside the sintered magnet body. To diffuse. For this reason, it is possible to diffuse the inside of the magnet body extremely efficiently without consuming Dy wastefully.

溶融塩の電解は、R−Fe−B系希土類焼結磁石体の粒界相を溶かし出すような高温で行う必要がなく、例えば600℃未満の低い温度で好適に実行することが可能である。また、焼結磁石体の表面に析出するDyの層厚の制御も容易であるため、その後にDy層の研磨工程は不要である。また、焼結磁石体の表面に形成されるDy層は、実質的に合金化しておらず、主としてDyから形成される。このため、Dyを焼結磁石体の内部にも効率的に拡散させることができる。   The electrolysis of the molten salt does not need to be performed at such a high temperature that the grain boundary phase of the R—Fe—B rare earth sintered magnet body is melted, and can be suitably executed at a low temperature of less than 600 ° C., for example. . Moreover, since it is easy to control the layer thickness of Dy deposited on the surface of the sintered magnet body, a polishing step for the Dy layer is not required after that. Further, the Dy layer formed on the surface of the sintered magnet body is not substantially alloyed and is mainly formed of Dy. For this reason, Dy can also be efficiently diffused into the sintered magnet body.

Dyの拡散により、希土類焼結磁石体中では主相外殻部において軽希土類元素RLをDyで置換することができるため、残留磁束密度Brの低下を抑制しつつ、保磁力HcJを上昇させることが可能になる。   Due to the diffusion of Dy, the light rare earth element RL can be replaced with Dy in the main phase outer shell in the rare earth sintered magnet body, so that the coercive force HcJ is increased while suppressing the decrease in the residual magnetic flux density Br. Is possible.

本発明によるR−Fe−B系希土類焼結磁石の製造方法では、まず、R−Fe−B系希土類焼結磁石体を用意する。このR−Fe−B系希土類焼結磁石体は、R2Fe14B型化合物結晶粒(主相)と希土類リッチな粒界相とを含んでいる。この段階におけるR−Fe−B系希土類焼結磁石体は軽希土類元素RL(NdおよびPrの少なくとも1種)を主たる希土類元素Rとして含有する。 In the method for producing an R—Fe—B rare earth sintered magnet according to the present invention, first, an R—Fe—B rare earth sintered magnet body is prepared. This R—Fe—B rare earth sintered magnet body includes R 2 Fe 14 B type compound crystal grains (main phase) and rare earth-rich grain boundary phases. The R—Fe—B rare earth sintered magnet body at this stage contains a light rare earth element RL (at least one of Nd and Pr) as a main rare earth element R.

次に、Dyイオンを含有する溶融塩中にR−Fe−B系希土類焼結磁石体を浸し、R−Fe−B系希土類焼結磁石体を陰極とする電解を行う。この電解により、溶融塩中のDyイオンがR−Fe−B系希土類焼結磁石体の表面に集まり、R−Fe−B系希土類焼結磁石体の表面にDyが電析する。こうしてDyが表面に電析した状態のR−Fe−B系希土類焼結磁石体を溶融塩から取り出した後、炉などの加熱処理室内に挿入する。加熱処理室内でR−Fe−B系希土類焼結磁石体に対する加熱処理を行うことにより、R−Fe−B系希土類焼結磁石体の表面から内部にDyを拡散させる。   Next, the R—Fe—B rare earth sintered magnet body is immersed in a molten salt containing Dy ions, and electrolysis is performed using the R—Fe—B rare earth sintered magnet body as a cathode. By this electrolysis, Dy ions in the molten salt gather on the surface of the R—Fe—B rare earth sintered magnet body, and Dy is electrodeposited on the surface of the R—Fe—B rare earth sintered magnet body. After the R—Fe—B rare earth sintered magnet body with Dy electrodeposited on the surface is taken out of the molten salt, it is inserted into a heat treatment chamber such as a furnace. By performing the heat treatment on the R—Fe—B rare earth sintered magnet body in the heat treatment chamber, Dy is diffused from the surface to the inside of the R—Fe—B rare earth sintered magnet body.

従来技術では、Dy層を焼結磁石体上に成長させる過程で、Dyの成膜材料供給源を極めて非効率的に消費してしまうことになる。例えばスパッタリング法によってDy層を焼結磁石体上に堆積する場合、Dyのターゲットを焼結磁石体に対向する位置に配置した状態でスパッタリングする必要がある。このとき、ターゲットからスパッタされたDyは、スパッタ装置内において焼結磁石体が存在しない部分にも衝突し、そこにも堆積してゆく。同様のことが、Dyの他の薄膜堆積技術(蒸着法など)を用いる場合にも生じる。すなわち、従来の薄膜堆積技術による場合、焼結磁石体に薄膜を堆積する工程でDyの多く(例えば80〜90%)が無駄に消費されてしまうという問題がある。   In the prior art, in the process of growing the Dy layer on the sintered magnet body, the Dy film-forming material supply source is consumed very inefficiently. For example, when a Dy layer is deposited on a sintered magnet body by a sputtering method, it is necessary to perform sputtering in a state where a Dy target is disposed at a position facing the sintered magnet body. At this time, Dy sputtered from the target collides with a portion where the sintered magnet body does not exist in the sputtering apparatus and accumulates there. The same thing occurs when using other thin film deposition techniques (such as vapor deposition) of Dy. That is, according to the conventional thin film deposition technique, there is a problem that much (for example, 80 to 90%) of Dy is wasted in the process of depositing the thin film on the sintered magnet body.

これに対し、本発明では、溶融塩中の電界によりDyイオンをR−Fe−B系希土類焼結磁石体の表面に引き寄せることができるため、無駄なく効率的にDyを次に行う拡散に利用することが可能になる。また、Dy合金の溶湯にR−Fe−B系希土類焼結磁石体を浸す従来技術に比べると、厚さの制御されたDy層を形成できる有利な効果が得られる。   On the other hand, in the present invention, Dy ions can be attracted to the surface of the R—Fe—B rare earth sintered magnet body by an electric field in the molten salt. It becomes possible to do. Further, as compared with the conventional technique in which the R—Fe—B rare earth sintered magnet body is immersed in the molten Dy alloy, an advantageous effect that a Dy layer having a controlled thickness can be formed.

なお、従来、溶融塩の電解は1000℃程度またはそれ以上の高温で行うことが主流であったため、R−Fe−B系希土類焼結磁石に対して適用可能な技術であるとは思われていなかった。本発明者の検討によると、溶融塩の選択を適切に行い、溶融温度を600℃未満に低下させると、電解中に焼結磁石の特性を劣化させることなく、Dy層の形成が可能であることがわかった。なお、本発明で形成するDy層は、その後に行うDy拡散源として機能すれば良く、緻密な膜に形成する必要も無い。   Conventionally, the electrolysis of molten salt has been mainly performed at a high temperature of about 1000 ° C. or higher, so it is considered to be a technology applicable to R—Fe—B rare earth sintered magnets. There wasn't. According to the study of the present inventor, when the molten salt is appropriately selected and the melting temperature is lowered to less than 600 ° C., the Dy layer can be formed without deteriorating the characteristics of the sintered magnet during electrolysis. I understood it. Note that the Dy layer formed in the present invention only needs to function as a Dy diffusion source to be performed later, and does not need to be formed into a dense film.

以下、図1を参照しながら、溶融塩中で電気分解を行うことにより、被処理材(陰極)として機能するR−Fe−B系希土類焼結磁石体の表面にDy層を形成するメカニズムを説明する。   Hereinafter, a mechanism for forming a Dy layer on the surface of an R—Fe—B rare earth sintered magnet body functioning as a material to be treated (cathode) by performing electrolysis in molten salt with reference to FIG. explain.

溶融塩の電解技術は、融点以上の温度に加熱し、溶融した塩で電気分解を行う技術であり、水の電気分解と同様の電解装置を用いて行われる。図1に示す電解装置10は、陰極(作用極)1、陽極(対極)2、および参照極(不図示)の三電極式セルと、電解浴3とを備えている。陰極1と参照極との間の電位や、セルに流れる電流は、ポテンショガルバノスタット4によって一定に保持される。   The molten salt electrolysis technique is a technique in which the molten salt is heated to a temperature equal to or higher than the melting point and electrolyzed with the molten salt, and is performed using an electrolysis apparatus similar to the electrolysis of water. An electrolysis apparatus 10 shown in FIG. 1 includes a three-electrode cell of a cathode (working electrode) 1, an anode (counter electrode) 2, and a reference electrode (not shown), and an electrolytic bath 3. The potential between the cathode 1 and the reference electrode and the current flowing through the cell are held constant by the potentiogalvanostat 4.

作用極として機能する陰極1には、R−Fe−B系焼結磁石体(被処理材)5が用いられる。参照極は、電気化学セルの電位の基準となる電極であり、Ag+/Ag電極のような電位の安定した電極が用いられる。参照極を使用することにより、参照極と陰極1との間の電位を測定・制御し、陰極1と陽極2との間に流れる電流を測定することができる。 An R—Fe—B based sintered magnet body (material to be processed) 5 is used for the cathode 1 that functions as a working electrode. The reference electrode is an electrode serving as a reference for the potential of the electrochemical cell, and an electrode having a stable potential such as an Ag + / Ag electrode is used. By using the reference electrode, the electric potential flowing between the cathode 1 and the anode 2 can be measured by measuring and controlling the potential between the reference electrode and the cathode 1.

電解浴3は、溶融塩に希土類元素が溶解した状態にある。溶融塩としては、LiCl、KCl、NaCl、NaF、KF、CsClなどのアルカリ金属ハライドや、CaCl2などのアルカリ土類金属ハライドが挙げられる。LiCl−KCl、LiCl−NaCl、NaCl−KCl、CsCl−LiClなどの共晶塩や、フェニルトリメチルアンモニウム、1-メチル-3-エチルイミダゾリウム、ブチルピリジニウムなどのイオン液体が好適に用いられる。 The electrolytic bath 3 is in a state where a rare earth element is dissolved in the molten salt. Examples of the molten salt include alkali metal halides such as LiCl, KCl, NaCl, NaF, KF, and CsCl, and alkaline earth metal halides such as CaCl 2 . Eutectic salts such as LiCl—KCl, LiCl—NaCl, NaCl—KCl, CsCl—LiCl, and ionic liquids such as phenyltrimethylammonium, 1-methyl-3-ethylimidazolium, and butylpyridinium are preferably used.

Dyは、溶融塩に溶解するようにハロゲン化物(DyX3、Xはハロゲンである。)として添加され、電解浴3中では、Dyイオン(Dy(III))として存在する。 Dy is added as a halide (DyX 3 , X is a halogen) so as to dissolve in the molten salt, and is present as Dy ions (Dy (III)) in the electrolytic bath 3.

電解浴3中でR−Fe−B系焼結磁石体5を陰極1とする電解を行うことにより、DyイオンはR−Fe−B系焼結磁石体5の表面で還元され、その結果、Dy層を形成する。この反応は、下式(1)で表される。   By performing electrolysis using the R—Fe—B based sintered magnet body 5 as the cathode 1 in the electrolytic bath 3, Dy ions are reduced on the surface of the R—Fe—B based sintered magnet body 5. A Dy layer is formed. This reaction is represented by the following formula (1).

Dy(III)+3e-→Dy・・・ (1) Dy (III) + 3e → Dy (1)

Dyイオンが還元されてDyを形成するための電位(電解電位)は、サイクリックボルタンメトリー(CV)法を用い、参照極に対する陰極の電圧と電流とを測定したサイクリックボルタモグラムに基づいて決定される。   The potential (electrolytic potential) for reducing Dy ions to form Dy is determined based on a cyclic voltammogram in which the voltage and current of the cathode with respect to the reference electrode are measured using a cyclic voltammetry (CV) method. .

次に、図2を参照しつつ、Dy層の形成方法をより具体的に説明する。図2には、陰極として機能するR−Fe−B系焼結磁石体11、陽極として機能するグラッシーカーボン12、参照極として機能するAg+/Ag電極13、および電解浴14が示されている。電極11、12、13は、電解セルを構成している。図2の装置は、電解浴14の温度を測定するための熱電対15と、装置内を不活性雰囲気下に制御してDyの酸化を防ぐためのアルゴンガス供給口16およびガス排気口17とをさらに備えている。 Next, the method for forming the Dy layer will be described more specifically with reference to FIG. FIG. 2 shows an R—Fe—B sintered magnet body 11 that functions as a cathode, glassy carbon 12 that functions as an anode, an Ag + / Ag electrode 13 that functions as a reference electrode, and an electrolytic bath 14. . The electrodes 11, 12, and 13 constitute an electrolytic cell. The apparatus of FIG. 2 includes a thermocouple 15 for measuring the temperature of the electrolytic bath 14, an argon gas supply port 16 and a gas exhaust port 17 for controlling the inside of the apparatus under an inert atmosphere to prevent oxidation of Dy. Is further provided.

電解浴14の温度は300℃超600℃未満の範囲に制御されることが好ましい。本発明者は、電解浴14の温度を変化させて実験を行ったところ、電解浴14の温度が300℃以下になるとDy形成速度が著しく低下し、生産性が悪いことが判明した。一方、電解浴14の温度が600℃以上になると、R−Fe−B系焼結磁石体の粒界相成分が浴中に溶け出し、磁石特性の劣化することもわかった。溶融させる塩は、上記の温度範囲で溶融する融点を有している必要があり、例えば、CsCl−LiCl(332℃)、LiCl−NaCl(融点約551℃〜557℃)、CaCl2−KCl(融点約594℃〜600℃)などが好適に用いられる。 The temperature of the electrolytic bath 14 is preferably controlled in the range of more than 300 ° C. and less than 600 ° C. The present inventor conducted experiments by changing the temperature of the electrolytic bath 14 and found that when the temperature of the electrolytic bath 14 was 300 ° C. or lower, the Dy formation rate was remarkably reduced and the productivity was poor. On the other hand, it was also found that when the temperature of the electrolytic bath 14 is 600 ° C. or higher, the grain boundary phase component of the R—Fe—B based sintered magnet body is dissolved in the bath and the magnetic properties are deteriorated. The salt to be melted must have a melting point that melts in the above temperature range. For example, CsCl—LiCl (332 ° C.), LiCl—NaCl (melting point: about 551 ° C. to 557 ° C.), CaCl 2 —KCl ( A melting point of about 594 ° C. to 600 ° C.) is preferably used.

本実施形態では、電極条件や溶融塩の種類などを適切に制御することにより、R−Fe−B系焼結磁石体の表面全体にDy層を形成することが可能である。電解浴14の温度などの電解条件は、目的とするDy層の厚さや膜質などに応じて適切に定めることができる。   In the present embodiment, the Dy layer can be formed on the entire surface of the R—Fe—B based sintered magnet body by appropriately controlling the electrode conditions and the type of molten salt. Electrolytic conditions such as the temperature of the electrolytic bath 14 can be appropriately determined according to the thickness and film quality of the target Dy layer.

こうしてR−Fe−B系焼結磁石体の表面にDy層を形成した後、Dyを表面から内部に拡散させるための熱処理を行う。   After forming the Dy layer on the surface of the R-Fe-B sintered magnet body in this way, heat treatment is performed to diffuse Dy from the surface to the inside.

本発明によれば、成膜のためにDy供給源をスパッタリングしたり、蒸発させる必要がないため、溶融塩に添加したDyを磁石体の内部に効率よく拡散させることが可能であり、貴重資源であるDyの省資源化に大いに寄与することとなる。   According to the present invention, since it is not necessary to sputter or evaporate the Dy supply source for film formation, it is possible to efficiently diffuse Dy added to the molten salt into the magnet body, which is a valuable resource. This greatly contributes to the resource saving of Dy.

本発明における拡散処理により、R2Fe14B主相結晶粒に含まれる軽希土類元素RLの一部を焼結体表面から粒界拡散によって内部に浸透させたDyで置換し、R2Fe14B主相の外殻部にDyが相対的に濃縮した層(厚さは例えば1nm)を形成することができる。 By the diffusion treatment in the present invention, a part of the light rare earth element RL contained in the R 2 Fe 14 B main phase crystal grains is substituted with Dy that has penetrated from the sintered body surface by grain boundary diffusion, and R 2 Fe 14 A layer (thickness is, for example, 1 nm) in which Dy is relatively concentrated can be formed on the outer shell of the B main phase.

R−Fe−B系希土類焼結磁石の保磁力発生機構はニュークリエーション型であるため、主相外殻部における結晶磁気異方性が高められると、主相における粒界相の近傍で逆磁区の核生成が抑制される結果、主相全体の保磁力HcJが効果的に向上する。本発明では、焼結磁石体の表面に近い領域だけでなく、磁石表面から奥深い領域においても重希土類置換層を主相外殻部に形成することができるため、磁石全体にわたって結晶磁気異方性が高められ、磁石全体の保磁力HcJが充分に向上することになる。したがって、本発明によれば、消費するDyの量が少なくとも、焼結体の内部までDyを拡散・浸透させることができ、主相外殻部で効率良くDy2Fe14Bを形成することにより、残留磁束密度Brの低下を抑制しつつ保磁力HcJを向上させることが可能になる。 Since the coercive force generation mechanism of the R—Fe—B rare earth sintered magnet is a nucleation type, if the magnetocrystalline anisotropy in the outer shell of the main phase is increased, a reverse magnetic domain is formed in the vicinity of the grain boundary phase in the main phase. As a result, the coercive force HcJ of the entire main phase is effectively improved. In the present invention, since the heavy rare earth substitution layer can be formed on the outer shell of the main phase not only in the area close to the surface of the sintered magnet body but also in the area deep from the magnet surface, And the coercive force HcJ of the whole magnet is sufficiently improved. Therefore, according to the present invention, the amount of Dy consumed can be at least diffused and permeated into the sintered body, and by efficiently forming Dy 2 Fe 14 B in the main phase outer shell portion Thus, it is possible to improve the coercive force HcJ while suppressing a decrease in the residual magnetic flux density Br.

上記説明から明らかなように、本発明では、原料合金の段階においてDyを添加しておく必要はない。すなわち、希土類元素Rとして軽希土類元素RL(NdおよびPrの少なくとも1種)を含有する公知のR−Fe−B系希土類焼結磁石を用意し、その表面から重希土類元素を磁石内部に拡散する。本発明は、原料合金の段階においてDyが幾らか添加されているR−Fe−B系焼結磁石に対して適用しても同様の効果が得られる。   As is clear from the above description, in the present invention, it is not necessary to add Dy in the raw material alloy stage. That is, a known R—Fe—B rare earth sintered magnet containing a light rare earth element RL (at least one of Nd and Pr) as a rare earth element R is prepared, and heavy rare earth elements are diffused from the surface into the magnet. . Even if the present invention is applied to an R—Fe—B based sintered magnet to which some Dy is added in the raw material alloy stage, the same effect can be obtained.

表面に電析したDyは、磁石界面におけるDy濃度の差を駆動力として、粒界相中を磁石内部に向かって拡散する。このとき、R2Fe14B相中の軽希土類元素RLの一部が、磁石表面から拡散浸透してきたDyによって置換される。その結果、R2Fe14B相の外殻部にDyが濃縮された層が形成される。 Dy electrodeposited on the surface diffuses in the grain boundary phase toward the inside of the magnet using the difference in Dy concentration at the magnet interface as a driving force. At this time, a part of the light rare earth element RL in the R 2 Fe 14 B phase is replaced by Dy that has diffused and penetrated from the magnet surface. As a result, a layer in which Dy is concentrated is formed in the outer shell of the R 2 Fe 14 B phase.

このようなDy濃縮層の形成により、主相外殻部の結晶磁気異方性が高められ、保磁力HcJが向上することになる。すなわち、少ないDy金属の使用により、磁石内部の奥深くにまでDyを拡散浸透させ、主相外殻部のみを効率的にDy2Fe14Bに変換するため、残留磁束密度Brの低下を抑制しつつ、磁石全体にわたって保磁力HcJを向上させることが可能になる。 By forming such a Dy enriched layer, the magnetocrystalline anisotropy of the main phase outer shell is increased, and the coercive force HcJ is improved. That is, by using a small amount of Dy metal, Dy is diffused and penetrated deep inside the magnet, and only the main phase outer shell is efficiently converted to Dy 2 Fe 14 B, so that the decrease in the residual magnetic flux density Br is suppressed. However, the coercive force HcJ can be improved over the entire magnet.

なお、実験によると、Dyの拡散浸透に伴って軽希土類元素RLは焼結磁石体内部から表面に向かって拡散し、磁石体表面にRL濃化層を形成することがわかった。このため、焼結磁石体内部における希土類元素の総量(主相の体積比率)は、ほとんど変化せず、残留磁束密度の低下が抑制される。   According to the experiment, it was found that the light rare earth element RL diffuses from the inside of the sintered magnet body toward the surface as Dy diffuses and penetrates to form an RL concentrated layer on the surface of the magnet body. For this reason, the total amount of rare earth elements inside the sintered magnet body (volume ratio of the main phase) hardly changes, and a decrease in residual magnetic flux density is suppressed.

前述のように、R−Fe−B系焼結磁石は、ニュークリエーションによる保磁力発生機構を有しているため、主相外殻部における結晶磁気異方性が高められることにより、主相の粒界相近傍における逆磁区の核生成が抑制され、保磁力HcJが高まる。   As described above, since the R—Fe—B based sintered magnet has a coercive force generation mechanism by nucleation, the crystal magnetic anisotropy in the main phase outer shell is increased, so that the main phase Nucleation of reverse magnetic domains in the vicinity of the grain boundary phase is suppressed, and the coercive force HcJ is increased.

また、拡散するDyの含有量は、磁石全体の重量比で0.1%以上1.5%以下の範囲に設定することが好ましい。1.5%を超えると、拡散に要する処理時間が長くなりすぎる可能性があり、0.1%未満では、保磁力HcJの向上効果が不充分だからである。上記の温度領域で、30〜180分熱処理することにより、0.1%〜1.5%の拡散量が達成できる。   Further, the content of Dy that diffuses is preferably set in a range of 0.1% to 1.5% by weight ratio of the whole magnet. If it exceeds 1.5%, the processing time required for diffusion may become too long, and if it is less than 0.1%, the effect of improving the coercive force HcJ is insufficient. A diffusion amount of 0.1% to 1.5% can be achieved by heat treatment in the above temperature range for 30 to 180 minutes.

焼結磁石体の表面状態はDyが拡散浸透しやすいよう、より金属状態の近い方が好ましく、電析前に酸洗浄やブラスト処理等の活性化処理を行った方がよいが、焼結磁石体の表面は、例えば切断加工が完了した後の酸化が進んだ状態にあってもよい。   The surface state of the sintered magnet body is preferably closer to the metal state so that Dy can easily diffuse and penetrate, and it is better to perform an activation treatment such as acid washing or blasting before electrodeposition. The surface of the body may be in a state where oxidation has progressed after the cutting process is completed, for example.

本発明によれば、僅かな量のDyを用いて残留磁束密度Brおよび保磁力HcJの両方を高め、高温でも磁気特性が低下しない高性能磁石を提供することができる。このような高性能磁石は、超小型・高出力モータの実現に大きく寄与する。粒界拡散を利用した本発明の効果は、厚さが10mm以下の磁石において特に顕著に発現する。   According to the present invention, it is possible to provide a high-performance magnet that increases both the residual magnetic flux density Br and the coercive force HcJ using a small amount of Dy, and does not deteriorate the magnetic characteristics even at high temperatures. Such a high-performance magnet greatly contributes to the realization of an ultra-small and high-power motor. The effect of the present invention using the grain boundary diffusion is particularly remarkable in a magnet having a thickness of 10 mm or less.

以下、本発明によるR−Fe−B系希土類焼結磁石を製造する方法の好ましい実施形態を説明する。   Hereinafter, a preferred embodiment of a method for producing an R—Fe—B rare earth sintered magnet according to the present invention will be described.

[原料合金]
まず、25質量%以上40質量%以下の軽希土類元素RLと、0.6質量%以上〜1.6質量%のB(硼素)と、残部Fe及び不可避的不純物とを含有する合金を用意する。Bの一部はC(炭素)によって置換されていてもよいし、Feの一部(50原子%以下)は、他の遷移金属元素(例えばCoまたはNi)によって置換されていてもよい。この合金は、種々の目的により、Al、Si、Ti、V、Cr、Mn、Ni、Cu、Zn、Ga、Zr、Nb、Mo、Ag、In、Sn、Hf、Ta、W、Pb、およびBiからなる群から選択された少なくとも1種の添加元素Mを0.01〜1.0質量%程度含有していてもよい。
[Raw material alloy]
First, an alloy containing a light rare earth element RL of 25% by mass or more and 40% by mass or less, B (boron) of 0.6% by mass to 1.6% by mass, the remainder Fe and inevitable impurities is prepared. . A part of B may be substituted by C (carbon), and a part of Fe (50 atomic% or less) may be substituted by another transition metal element (for example, Co or Ni). This alloy is suitable for a variety of purposes, including Al, Si, Ti, V, Cr, Mn, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ag, In, Sn, Hf, Ta, W, Pb, and About 0.01 to 1.0% by mass of at least one additive element M selected from the group consisting of Bi may be contained.

上記の合金は、原料合金の溶湯を例えばストリップキャスト法によって急冷して好適に作製され得る。以下、ストリップキャスト法による急冷凝固合金の作製を説明する。   The above-mentioned alloy can be suitably produced by rapidly cooling a molten raw material alloy by, for example, a strip casting method. Hereinafter, preparation of a rapidly solidified alloy by a strip casting method will be described.

まず、上記組成を有する原料合金をアルゴン雰囲気中において高周波溶解によって溶融し、原料合金の溶湯を形成する。次に、この溶湯を1350℃程度に保持した後、単ロール法によって急冷し、例えば厚さ約0.3mmのフレーク状合金鋳塊を得る。こうして作製した合金鋳片を、次の水素粉砕前に例えば1〜10mmの大きさのフレーク状に粉砕する。なお、ストリップキャスト法による原料合金の製造方法は、例えば、米国特許第5、383、978号明細書に開示されている。   First, a raw material alloy having the above composition is melted by high frequency melting in an argon atmosphere to form a molten raw material alloy. Next, after this molten metal is kept at about 1350 ° C., it is rapidly cooled by a single roll method to obtain a flaky alloy ingot having a thickness of about 0.3 mm, for example. The alloy slab thus produced is pulverized into flakes having a size of 1 to 10 mm, for example, before the next hydrogen pulverization. In addition, the manufacturing method of the raw material alloy by a strip cast method is disclosed by US Patent 5,383,978 specification, for example.

[粗粉砕工程]
上記のフレーク状に粗く粉砕された合金鋳片を水素炉の内部へ収容する。次に、水素炉の内部で水素脆化処理(以下、「水素粉砕処理」と称する場合がある)工程を行なう。水素粉砕後の粗粉砕合金粉末を水素炉から取り出す際、粗粉砕粉が大気と接触しないように、不活性雰囲気下で取り出し動作を実行することが好ましい。そうすれば、粗粉砕粉が酸化・発熱することが防止され、磁石の磁気特性が向上するからである。
[Coarse grinding process]
The alloy slab coarsely crushed into flakes is accommodated in the hydrogen furnace. Next, a hydrogen embrittlement process (hereinafter sometimes referred to as “hydrogen pulverization process”) is performed inside the hydrogen furnace. When the coarsely pulverized alloy powder after hydrogen pulverization is taken out from the hydrogen furnace, it is preferable to perform the take-out operation in an inert atmosphere so that the coarsely pulverized powder does not come into contact with the atmosphere. This is because the coarsely pulverized powder is prevented from oxidizing and generating heat, and the magnetic properties of the magnet are improved.

水素粉砕によって、希土類合金は0.1mm〜数mm程度の大きさに粉砕され、その平均粒径は500μm以下となる。水素粉砕後、脆化した原料合金をより細かく解砕するとともに冷却することが好ましい。比較的高い温度状態のまま原料を取り出す場合は、冷却処理の時間を相対的に長くすれば良い。   By the hydrogen pulverization, the rare earth alloy is pulverized to a size of about 0.1 mm to several mm, and the average particle size becomes 500 μm or less. After the hydrogen pulverization, the embrittled raw material alloy is preferably crushed more finely and cooled. In the case where the raw material is taken out in a relatively high temperature state, the cooling process time may be relatively long.

[微粉砕工程]
次に、粗粉砕粉に対してジェットミル粉砕装置を用いて微粉砕を実行する。本実施形態で使用するジェットミル粉砕装置にはサイクロン分級機が接続されている。ジェットミル粉砕装置は、粗粉砕工程で粗く粉砕された希土類合金(粗粉砕粉)の供給を受け、粉砕機内で粉砕する。粉砕機内で粉砕された粉末はサイクロン分級機を経て回収タンクに集められる。こうして、0.1〜20μm程度(典型的には3〜5μm)の微粉末を得ることができる。このような微粉砕に用いる粉砕装置は、ジェットミルに限定されず、アトライタやボールミルであってもよい。粉砕に際して、ステアリン酸亜鉛などの潤滑剤を粉砕助剤として用いてもよい。
[Fine grinding process]
Next, the coarsely pulverized powder is finely pulverized using a jet mill pulverizer. A cyclone classifier is connected to the jet mill crusher used in the present embodiment. The jet mill pulverizer is supplied with the rare earth alloy (coarse pulverized powder) coarsely pulverized in the coarse pulverization step, and pulverizes in the pulverizer. The powder pulverized in the pulverizer is collected in a collection tank through a cyclone classifier. Thus, a fine powder of about 0.1 to 20 μm (typically 3 to 5 μm) can be obtained. The pulverizer used for such fine pulverization is not limited to a jet mill, and may be an attritor or a ball mill. In grinding, a lubricant such as zinc stearate may be used as a grinding aid.

[プレス成形]
本実施形態では、上記方法で作製された磁性粉末に対し、例えばロッキングミキサー内で潤滑剤を例えば0.3wt%添加・混合し、潤滑剤で合金粉末粒子の表面を被覆する。次に、上述の方法で作製した磁性粉末を公知のプレス装置を用いて配向磁界中で成形する。印加する磁界の強度は、例えば1.5〜1.7テスラ(T)である。また、成形圧力は、成形体のグリーン密度が例えば4〜4.5g/cm3程度になるように設定される。
[Press molding]
In this embodiment, for example, 0.3 wt% of a lubricant is added to and mixed with the magnetic powder produced by the above method in a rocking mixer, and the surface of the alloy powder particles is coated with the lubricant. Next, the magnetic powder produced by the above-described method is molded in an orientation magnetic field using a known press machine. The intensity of the applied magnetic field is, for example, 1.5 to 1.7 Tesla (T). The molding pressure is set so that the green density of the molded body is, for example, about 4 to 4.5 g / cm 3 .

[焼結工程]
上記の粉末成形体に対して、650〜1000℃の範囲内の温度で10〜240分間保持する工程と、その後、上記の保持温度よりも高い温度(例えば1000〜1200℃)で焼結を更に進める工程とを順次行なうことが好ましい。焼結時、特に液相が生成されるとき(温度が650〜1000℃の範囲内にあるとき)、粒界相中のRリッチ相が融け始め、液相が形成される。その後、焼結が進行し、焼結磁石体が形成される。焼結後、必要に応じて、時効処理(500〜1000℃)が行われる。
[Sintering process]
With respect to said powder molded object, the process hold | maintained for 10 to 240 minutes at the temperature within the range of 650-1000 degreeC, and sintering further by the temperature (for example, 1000-1200 degreeC) higher than said holding temperature after that. It is preferable to sequentially perform the proceeding steps. During sintering, particularly when a liquid phase is generated (when the temperature is in the range of 650 to 1000 ° C.), the R-rich phase in the grain boundary phase begins to melt and a liquid phase is formed. Then, sintering progresses and a sintered magnet body is formed. After sintering, an aging treatment (500 to 1000 ° C.) is performed as necessary.

[Dy電析工程]
次に、図2を参照しながら説明した方法により、Dyが溶けた溶融塩中で焼結磁石体を陰極とする電解を行い、焼結磁石体の表面にDyを効率良く形成する。
[Dy electrodeposition process]
Next, by the method described with reference to FIG. 2, electrolysis using the sintered magnet body as a cathode in molten salt in which Dy is dissolved is performed, and Dy is efficiently formed on the surface of the sintered magnet body.

適切な量のDyを磁石体中に拡散させるためには、表面に電析するDy層の厚さを1〜10μmの範囲に設定することが好ましい。そのためには、定電位電解で0.1〜0.5V(v.s.Li+/Li)の電位にて、1〜15時間電解するのが好ましい。   In order to diffuse an appropriate amount of Dy into the magnet body, the thickness of the Dy layer deposited on the surface is preferably set in the range of 1 to 10 μm. For this purpose, it is preferable to perform electrolysis at a potential of 0.1 to 0.5 V (vs. Li + / Li) by constant potential electrolysis for 1 to 15 hours.

本実施形態によれば、Dyをスパッタリングしたり、蒸発させたりすることなく、磁石表面に歩留まり良く、成膜できるため、少ないDy量で、高い保磁力の高性能希土類磁石を得ることができる。また、特許文献4におけるような処理後の研削工程などの必要もない。   According to this embodiment, since film formation can be performed on the magnet surface with good yield without sputtering or evaporating Dy, a high-performance rare earth magnet having a high coercive force can be obtained with a small amount of Dy. Further, there is no need for a grinding process after the treatment as in Patent Document 4.

[拡散工程]
次に、焼結磁石体の表面から内部にDyを拡散浸透させて、保磁力HcJを向上させる。具体的には、表面にDyが析出した状態の焼結磁石体を処理室内に配置し、加熱により、Dyを焼結磁石体の表面から内部に拡散させる。
[Diffusion process]
Next, Dy is diffused and penetrated from the surface of the sintered magnet body to improve the coercive force HcJ. Specifically, a sintered magnet body having Dy deposited on the surface is disposed in the processing chamber, and Dy is diffused from the surface of the sintered magnet body to the inside by heating.

拡散のための熱処理は、R−Fe−B系希土類焼結磁石体を処理室内に静置させた状態で処理室の雰囲気全体を加熱することによって行っても良いし、高周波誘導加熱等により、焼結磁石体を直接加熱することによって行っても良い。   The heat treatment for diffusion may be performed by heating the entire atmosphere of the processing chamber in a state where the R-Fe-B rare earth sintered magnet body is left in the processing chamber, or by high-frequency induction heating or the like, You may carry out by heating a sintered magnet body directly.

処理室内の加熱温度は700℃〜1000℃が好ましく、850℃〜950℃がより好ましい。この温度領域であれば、Dyが焼結磁石体の粒界相を伝って内部へ効率よく拡散する。上記温度領域で拡散を行う場合、30〜180分程度の熱処理により、焼結磁石体の重量に対して0.1%〜1%の比率でDyを含有するように拡散を行うことができる。   The heating temperature in the treatment chamber is preferably 700 ° C to 1000 ° C, and more preferably 850 ° C to 950 ° C. In this temperature region, Dy diffuses efficiently through the grain boundary phase of the sintered magnet body. When diffusion is performed in the above temperature range, the diffusion can be performed by heat treatment for about 30 to 180 minutes so that Dy is contained at a ratio of 0.1% to 1% with respect to the weight of the sintered magnet body.

なお、本明細書における「処理室」は、焼結磁石体を含み得る空間を広く含むものであり、熱処理炉の処理室を意味する場合もあれば、そのような処理室内に収容される処理容器を意味する場合もある。   In addition, the “processing chamber” in this specification includes a space that can include a sintered magnet body, and may mean a processing chamber of a heat treatment furnace, or may be a process accommodated in such a processing chamber. It may also mean a container.

熱処理時における処理室内は不活性雰囲気であることが好ましい。本明細書における「不活性雰囲気」とは、真空、また不活性ガスで満たされた状態を含むものとする。また、「不活性ガス」は、例えばアルゴン(Ar)などの希ガスであるが、焼結磁石体との間で化学的に反応しないガスであれば、「不活性ガス」に含まれ得る。   The inside of the treatment chamber during the heat treatment is preferably an inert atmosphere. The “inert atmosphere” in this specification includes a state filled with a vacuum or an inert gas. The “inert gas” is a rare gas such as argon (Ar), for example, but may be included in the “inert gas” as long as it does not chemically react with the sintered magnet body.

本実施形態における拡散工程は、焼結磁石体の表面状況に敏感ではなく、拡散工程の前に焼結磁石体の表面にZnやSnなどからなる膜が形成されていてもよい。ZnやSnは、低融点金属であり、しかも、少量であれば磁石特性を劣化させず、また上記の拡散の障害ともならないからである。   The diffusion process in this embodiment is not sensitive to the surface condition of the sintered magnet body, and a film made of Zn, Sn, or the like may be formed on the surface of the sintered magnet body before the diffusion process. This is because Zn and Sn are low melting point metals, and if they are in a small amount, they do not deteriorate the magnetic properties and do not hinder the diffusion described above.

まず、Nd:31.8、B:0.97、Co:0.92、Cu:0.1、Al:0.24、残部:Fe(質量%)の組成を有するように配合した合金のインゴットをストリップキャスト装置により溶融し、冷却することによって凝固した。こうして、厚さ0.2〜0.3mmの合金薄片を作製した。   First, an ingot of an alloy blended so as to have a composition of Nd: 31.8, B: 0.97, Co: 0.92, Cu: 0.1, Al: 0.24, and the balance: Fe (% by mass) Was melted by a strip casting apparatus and solidified by cooling. Thus, alloy flakes having a thickness of 0.2 to 0.3 mm were produced.

次に、この合金薄片を容器内に充填し、水素処理装置内に収容した。そして、水素処理装置内に圧力500kPaの水素ガス雰囲気で満たすことにより、室温で合金薄片に水素吸蔵させた後、放出させた。このような水素処理を行うことにより、合金薄片を脆化し、大きさ約0.15〜0.2mmの不定形粉末を作製した。   Next, this alloy flake was filled in a container and accommodated in a hydrogen treatment apparatus. Then, the hydrogen treatment apparatus was filled with a hydrogen gas atmosphere at a pressure of 500 kPa, so that hydrogen was occluded in the alloy flakes at room temperature and then released. By performing such a hydrogen treatment, the alloy flakes were embrittled to produce an amorphous powder having a size of about 0.15 to 0.2 mm.

上記の水素処理により作製した粗粉砕粉末に対し粉砕助剤として0.05wt%のステアリン酸亜鉛を添加し混合した後、ジェットミル装置による粉砕工程を行うことにより、粉末粒径が約3μmの微粉末を製作した。   After adding 0.05 wt% zinc stearate as a grinding aid to the coarsely pulverized powder produced by the hydrogen treatment described above and mixing, a pulverization step using a jet mill device is performed, so that the powder particle size is about 3 μm. Powder was produced.

こうして作製した微粉末をプレス装置により成形し、粉末成形体を作製した。具体的には、印加磁界中で粉末粒子を磁界配向した状態で圧縮し、プレス成形を行った。その後、成形体をプレス装置から抜き出し、真空炉により1020℃で4時間の焼結工程を行った。こうして、15mm角の立方体形状を有する焼結体ブロックを作製したあと、この焼結体ブロックを機械的に加工することにより、厚さ(磁化方向サイズ)1mm×縦10mm×横10mmの焼結磁石体を複数個作製した。   The fine powder thus produced was molded by a press apparatus to produce a powder compact. Specifically, the powder particles were compressed in a magnetic field-oriented state in an applied magnetic field and pressed. Thereafter, the molded body was extracted from the press apparatus and subjected to a sintering process at 1020 ° C. for 4 hours in a vacuum furnace. Thus, after producing a sintered body block having a 15 mm square cube shape, the sintered body block is mechanically processed to obtain a sintered magnet having a thickness (magnetization direction size) of 1 mm × length of 10 mm × width of 10 mm. Several bodies were made.

次に、この焼結磁石体に対し、以下の表1に示す条件でDy電析を行った。溶融塩としは、無水DyCl3(1.0mol%)を含むCsCl−LiCl(42mol%−58mol%)またはLiCl−KCl(57mol%−43mol%)を用いた。これら溶融塩を100℃で3日間真空乾燥した後、所定の温度に保ち、電解浴を形成した。電解処理の条件は、以下の表1に示すとおりである。 Next, Dy electrodeposition was performed on the sintered magnet body under the conditions shown in Table 1 below. A molten salt, using anhydrous DyCl 3 CsCl-LiCl containing (1.0mol%) (42mol% -58mol %) or LiCl-KCl (57mol% -43mol% ). These molten salts were vacuum-dried at 100 ° C. for 3 days, and then maintained at a predetermined temperature to form an electrolytic bath. The conditions for the electrolytic treatment are as shown in Table 1 below.

上記焼結磁石体を作用極(陰極)として電解浴中に浸し、0.2V(v.s.Li/Li+)の電解電位で所定時間の電解を行った。電解処理後の焼結磁石体の表面には、Dy層が形成された。電解浴から焼結磁石体を取り出した後、磁石表面に残存する溶融塩を除去するとともに酸化防止のため、焼結磁石体をエチレングリコールに浸漬した。   The sintered magnet body was immersed in an electrolytic bath as a working electrode (cathode), and electrolysis was performed for a predetermined time at an electrolytic potential of 0.2 V (vs Li / Li +). A Dy layer was formed on the surface of the sintered magnet body after the electrolytic treatment. After removing the sintered magnet body from the electrolytic bath, the molten salt remaining on the magnet surface was removed and the sintered magnet body was immersed in ethylene glycol to prevent oxidation.

次に、得られた試料を真空熱処理炉にて900℃、60min、1.0×10-2Paの条件で熱処理した後、500℃、60min、2Paの条件で時効処理を行った。 Next, the obtained sample was heat-treated in a vacuum heat treatment furnace under the conditions of 900 ° C., 60 min, and 1.0 × 10 −2 Pa, and then subjected to aging treatment under the conditions of 500 ° C., 60 min, and 2 Pa.

次に、B−Hトレーサを用いて磁石特性(残留磁束密度:Br、保磁力:HcJ)を測定した。また、Dyの電析状況や拡散状況はEPMA(島津製作所製EPM−810)にて評価した。   Next, magnet characteristics (residual magnetic flux density: Br, coercive force: HcJ) were measured using a B-H tracer. Moreover, the electrodeposition state and diffusion state of Dy were evaluated by EPMA (EPM-810, manufactured by Shimadzu Corporation).

表2および図3に磁石特性を示す。ここで、「比較例」は、試料1〜5と同様にして製造された焼結磁石体であるが、Dy層の形成およびDy拡散を行わなかった点で試料1〜5と異なっている。これらの結果からわかるように、本実施例の方法によれば、保磁力が向上した。   Table 2 and FIG. 3 show the magnet characteristics. Here, the “Comparative Example” is a sintered magnet body manufactured in the same manner as Samples 1 to 5, but differs from Samples 1 to 5 in that the Dy layer was not formed and Dy diffusion was not performed. As can be seen from these results, the coercive force was improved by the method of this example.

図4は、試料4のDy電析後における表面EPMA分析結果を示す写真であり、図5は、試料4の熱処理後における断面EPMA分析結果を示す写真である。図4および図5から、Dyが焼結磁石体内部の粒界相へ拡散していることがわかる。   FIG. 4 is a photograph showing the results of surface EPMA analysis after Dy electrodeposition of sample 4, and FIG. 5 is a photograph showing the results of cross-sectional EPMA analysis after heat treatment of sample 4. 4 and 5 that Dy diffuses into the grain boundary phase inside the sintered magnet body.

本発明によれば、Dyを無駄に消費することなく、焼結磁石体の内部に効率よく拡散し、主相結晶粒の外殻部にDyが濃縮することができるため、高い残留磁束密度と高い保磁力とを兼ね備えた高性能磁石を提供することができる。   According to the present invention, Dy can be efficiently diffused inside the sintered magnet body without wasting Dy, and Dy can be concentrated in the outer shell portion of the main phase crystal grains. A high-performance magnet having a high coercive force can be provided.

溶融塩の電解を示す模式図である。It is a schematic diagram which shows electrolysis of molten salt. 本発明の実施形態で好適に用いられる電解装置の構成例を示す図である。It is a figure which shows the structural example of the electrolyzer suitably used by embodiment of this invention. 本発明の実施例について得られた磁石特性を示すグラフであり、(a)は残留磁束密度Brを示すグラフであり、(b)は保磁力HcJを示すグラフである。It is a graph which shows the magnet characteristic acquired about the Example of this invention, (a) is a graph which shows the residual magnetic flux density Br, (b) is a graph which shows the coercive force HcJ. 本発明の実施例(試料4)について得られた表面EPMA分析結果を示す写真であり、(a)は、電解前の状態を示し、(b)は、500℃12時間の電解を行った後の状態を示している。It is a photograph which shows the surface EPMA analysis result obtained about the Example (sample 4) of this invention, (a) shows the state before electrolysis, (b) after performing electrolysis of 500 degreeC for 12 hours. Shows the state. 本発明の実施例(試料4)について得られた断面EPMA分析結果を示す写真であり、(a)は、電解前の状態を示し、(b)は、500℃12時間の電解と拡散熱処理を行った後の状態を示している。It is the photograph which shows the cross-sectional EPMA analysis result obtained about the Example (sample 4) of this invention, (a) shows the state before electrolysis, (b) is 500 degreeC 12 hours of electrolysis and diffusion heat processing. The state after performing is shown.

Claims (7)

軽希土類元素RL(NdおよびPrの少なくとも1種)を主たる希土類元素Rとして含有するR2Fe14B型化合物結晶粒を主相として有する少なくとも1つのR−Fe−B系希土類焼結磁石体を用意する工程(A)と、
Dyイオンを含有する溶融塩中で電解を行うことにより、前記R−Fe−B系希土類焼結磁石体の表面にDyを電析させる工程(B)と、
前記Dyが表面に電析したR−Fe−B系希土類焼結磁石体を加熱することにより、前記R−Fe−B系希土類焼結磁石体の内部にDyを拡散させる工程(C)と、
を包含するR−Fe−B系希土類焼結磁石の製造方法。
At least one R—Fe—B rare earth sintered magnet body having R 2 Fe 14 B type compound crystal grains containing a light rare earth element RL (at least one of Nd and Pr) as a main rare earth element R as a main phase. Step (A) to be prepared,
A step (B) of depositing Dy on the surface of the R-Fe-B rare earth sintered magnet body by performing electrolysis in a molten salt containing Dy ions;
A step (C) of diffusing Dy inside the R-Fe-B rare earth sintered magnet body by heating the R-Fe-B rare earth sintered magnet body on which the Dy is electrodeposited;
Method of R-Fe-B rare earth sintered magnet including
前記工程(B)において、前記溶融塩の温度を300℃以上600℃未満に設定した状態で電解を行う請求項1に記載のR−Fe−B系希土類焼結磁石の製造方法。   2. The method for producing an R—Fe—B rare earth sintered magnet according to claim 1, wherein in the step (B), electrolysis is performed in a state where the temperature of the molten salt is set to 300 ° C. or more and less than 600 ° C. 3. 前記工程(C)において、前記R−Fe−B系希土類焼結磁石体の加熱温度を700℃以上1000℃以下の範囲内に設定する請求項1に記載のR−Fe−B系希土類焼結磁石の製造方法。   2. The R—Fe—B rare earth sintered body according to claim 1, wherein in the step (C), the heating temperature of the R—Fe—B rare earth sintered magnet body is set within a range of 700 ° C. or higher and 1000 ° C. or lower. Magnet manufacturing method. 前記工程(C)において、前記処理室内を真空または不活性雰囲気で満たした状態で加熱処理を行う、請求項1に記載のR−Fe−B系希土類焼結磁石の製造方法。   2. The method for producing an R—Fe—B rare earth sintered magnet according to claim 1, wherein in the step (C), heat treatment is performed in a state where the processing chamber is filled with a vacuum or an inert atmosphere. 前記溶融塩として、アルカリ金属ハライドまたはアルカリ土類金属ハライドを用いる請求項1に記載のR−Fe−B系焼結磁石の製造方法。   The method for producing an R—Fe—B based sintered magnet according to claim 1, wherein an alkali metal halide or an alkaline earth metal halide is used as the molten salt. 前記溶融塩として、LiCl−KClまたはCsCl−LiClを用いる請求項1に記載のR−Fe−B系焼結磁石の製造方法。   The method for producing an R—Fe—B based sintered magnet according to claim 1, wherein LiCl—KCl or CsCl—LiCl is used as the molten salt. 前記工程(B)において、1μm以上10μm以下の厚さを有するDy層を前記R−Fe−B系希土類焼結磁石体の表面に形成する請求項1に記載のR−Fe−B系焼結磁石の製造方法。   2. The R—Fe—B based sintering according to claim 1, wherein in the step (B), a Dy layer having a thickness of 1 μm to 10 μm is formed on a surface of the R—Fe—B based rare earth sintered magnet body. Magnet manufacturing method.
JP2006115225A 2006-04-19 2006-04-19 Method for producing R-Fe-B rare earth sintered magnet Active JP4742966B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2006115225A JP4742966B2 (en) 2006-04-19 2006-04-19 Method for producing R-Fe-B rare earth sintered magnet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2006115225A JP4742966B2 (en) 2006-04-19 2006-04-19 Method for producing R-Fe-B rare earth sintered magnet

Publications (2)

Publication Number Publication Date
JP2007288021A true JP2007288021A (en) 2007-11-01
JP4742966B2 JP4742966B2 (en) 2011-08-10

Family

ID=38759484

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2006115225A Active JP4742966B2 (en) 2006-04-19 2006-04-19 Method for producing R-Fe-B rare earth sintered magnet

Country Status (1)

Country Link
JP (1) JP4742966B2 (en)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009004794A1 (en) * 2007-07-02 2009-01-08 Hitachi Metals, Ltd. R-fe-b type rare earth sintered magnet and process for production of the same
WO2009016815A1 (en) * 2007-07-27 2009-02-05 Hitachi Metals, Ltd. R-Fe-B RARE EARTH SINTERED MAGNET
JP2010129665A (en) * 2008-11-26 2010-06-10 Ulvac Japan Ltd Method of manufacturing permanent magnet
WO2011064636A1 (en) 2009-11-26 2011-06-03 Toyota Jidosha Kabushiki Kaisha Method for producing sintered rare-earth magnet, sintered rare-earth magnet, and material for same
EP2555207A1 (en) * 2010-03-30 2013-02-06 TDK Corporation Rare earth sintered magnet, method for producing the same, motor, and automobile
WO2014034851A1 (en) * 2012-08-31 2014-03-06 信越化学工業株式会社 Production method for rare earth permanent magnet
WO2014034849A1 (en) * 2012-08-31 2014-03-06 信越化学工業株式会社 Production method for rare earth permanent magnet
WO2014034854A1 (en) * 2012-08-31 2014-03-06 信越化学工業株式会社 Production method for rare earth permanent magnet
WO2015078619A1 (en) * 2013-11-26 2015-06-04 Siemens Aktiengesellschaft Permanent magnet having increased coercivity
JP2015154051A (en) * 2014-02-19 2015-08-24 信越化学工業株式会社 Method for manufacturing rare earth permanent magnet
CN105428049A (en) * 2014-09-12 2016-03-23 西门子公司 Electrochemical deposition of Nd for improving coercive field strength of rare earth permanent magnet
JP2018082193A (en) * 2017-02-08 2018-05-24 ティアンヘ (パオトウ) アドヴァンスト テック マグネット カンパニー リミテッド Manufacturing method of permanent magnet material
US10017871B2 (en) 2014-02-19 2018-07-10 Shin-Etsu Chemical Co., Ltd. Electrodepositing apparatus and preparation of rare earth permanent magnet
JP2018137420A (en) * 2016-10-27 2018-08-30 有研稀土新材料股▲フン▼有限公司 High-coercive force neodymium-iron-boron rare earth permanent magnet and manufacturing process thereof
CN108565088A (en) * 2018-05-25 2018-09-21 严高林 A kind of band coating sintered NdFeB magnet and preparation method thereof
CN114783755A (en) * 2022-04-20 2022-07-22 杨杭福 Method for preparing samarium-iron-nitrogen magnet through electric field and thermal field co-assistance

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10335125A (en) * 1997-06-02 1998-12-18 Sumitomo Metal Mining Co Ltd R-fe-b system alloy powder for permanent magnet
JP2000096102A (en) * 1998-09-18 2000-04-04 Aichi Steel Works Ltd Heat resistant rare earth alloy anisotropy magnet powder
JP2005011973A (en) * 2003-06-18 2005-01-13 Japan Science & Technology Agency Rare earth-iron-boron based magnet and its manufacturing method
WO2006064848A1 (en) * 2004-12-16 2006-06-22 Japan Science And Technology Agency Nd-Fe-B MAGNET WITH MODIFIED GRAIN BOUNDARY AND PROCESS FOR PRODUCING THE SAME

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10335125A (en) * 1997-06-02 1998-12-18 Sumitomo Metal Mining Co Ltd R-fe-b system alloy powder for permanent magnet
JP2000096102A (en) * 1998-09-18 2000-04-04 Aichi Steel Works Ltd Heat resistant rare earth alloy anisotropy magnet powder
JP2005011973A (en) * 2003-06-18 2005-01-13 Japan Science & Technology Agency Rare earth-iron-boron based magnet and its manufacturing method
WO2006064848A1 (en) * 2004-12-16 2006-06-22 Japan Science And Technology Agency Nd-Fe-B MAGNET WITH MODIFIED GRAIN BOUNDARY AND PROCESS FOR PRODUCING THE SAME

Cited By (36)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009004794A1 (en) * 2007-07-02 2009-01-08 Hitachi Metals, Ltd. R-fe-b type rare earth sintered magnet and process for production of the same
US8187392B2 (en) 2007-07-02 2012-05-29 Hitachi Metals, Ltd. R-Fe-B type rare earth sintered magnet and process for production of the same
WO2009016815A1 (en) * 2007-07-27 2009-02-05 Hitachi Metals, Ltd. R-Fe-B RARE EARTH SINTERED MAGNET
JP5532922B2 (en) * 2007-07-27 2014-06-25 日立金属株式会社 R-Fe-B rare earth sintered magnet
US8177921B2 (en) 2007-07-27 2012-05-15 Hitachi Metals, Ltd. R-Fe-B rare earth sintered magnet
JP2010129665A (en) * 2008-11-26 2010-06-10 Ulvac Japan Ltd Method of manufacturing permanent magnet
DE112010004576B4 (en) 2009-11-26 2023-01-26 Toyota Jidosha Kabushiki Kaisha Process for producing a sintered rare earth magnet, rare earth magnet and material therefor
WO2011064636A1 (en) 2009-11-26 2011-06-03 Toyota Jidosha Kabushiki Kaisha Method for producing sintered rare-earth magnet, sintered rare-earth magnet, and material for same
DE112010004576T5 (en) 2009-11-26 2012-12-13 Toyota Jidosha Kabushiki Kaisha A process for producing a sintered rare earth magnet, sintered rare earth magnet and material therefor
US9640305B2 (en) 2009-11-26 2017-05-02 Toyota Jidosha Kabushiki Kaisha Method for producing sintered rare-earth magnet, sintered rare-earth magnet, and material for same
JP2011114149A (en) * 2009-11-26 2011-06-09 Toyota Motor Corp Method for manufacturing sintered rare earth magnet
CN102741955A (en) * 2009-11-26 2012-10-17 丰田自动车株式会社 Method for producing sintered rare-earth magnet, sintered rare-earth magnet, and material for same
EP2555207A1 (en) * 2010-03-30 2013-02-06 TDK Corporation Rare earth sintered magnet, method for producing the same, motor, and automobile
US9350203B2 (en) 2010-03-30 2016-05-24 Tdk Corporation Rare earth sintered magnet, method for producing the same, motor, and automobile
EP2555207A4 (en) * 2010-03-30 2015-12-16 Tdk Corp Rare earth sintered magnet, method for producing the same, motor, and automobile
JP2014063996A (en) * 2012-08-31 2014-04-10 Shin Etsu Chem Co Ltd Method for producing rare earth permanent magnet
JP2014063998A (en) * 2012-08-31 2014-04-10 Shin Etsu Chem Co Ltd Method for producing rare earth permanent magnet
CN104584157A (en) * 2012-08-31 2015-04-29 信越化学工业株式会社 Production method for rare earth permanent magnet
US10138564B2 (en) 2012-08-31 2018-11-27 Shin-Etsu Chemical Co., Ltd. Production method for rare earth permanent magnet
WO2014034854A1 (en) * 2012-08-31 2014-03-06 信越化学工業株式会社 Production method for rare earth permanent magnet
JP2014063997A (en) * 2012-08-31 2014-04-10 Shin Etsu Chem Co Ltd Method for producing rare earth permanent magnet
US10179955B2 (en) 2012-08-31 2019-01-15 Shin-Etsu Chemical Co., Ltd. Production method for rare earth permanent magnet
WO2014034849A1 (en) * 2012-08-31 2014-03-06 信越化学工業株式会社 Production method for rare earth permanent magnet
WO2014034851A1 (en) * 2012-08-31 2014-03-06 信越化学工業株式会社 Production method for rare earth permanent magnet
US10181377B2 (en) 2012-08-31 2019-01-15 Shin-Etsu Chemical Co., Ltd. Production method for rare earth permanent magnet
WO2015078619A1 (en) * 2013-11-26 2015-06-04 Siemens Aktiengesellschaft Permanent magnet having increased coercivity
US10017871B2 (en) 2014-02-19 2018-07-10 Shin-Etsu Chemical Co., Ltd. Electrodepositing apparatus and preparation of rare earth permanent magnet
US9845545B2 (en) 2014-02-19 2017-12-19 Shin-Etsu Chemical Co., Ltd. Preparation of rare earth permanent magnet
US10526715B2 (en) 2014-02-19 2020-01-07 Shin-Etsu Chemical Co., Ltd. Preparation of rare earth permanent magnet
JP2015154051A (en) * 2014-02-19 2015-08-24 信越化学工業株式会社 Method for manufacturing rare earth permanent magnet
CN105428049A (en) * 2014-09-12 2016-03-23 西门子公司 Electrochemical deposition of Nd for improving coercive field strength of rare earth permanent magnet
JP2018137420A (en) * 2016-10-27 2018-08-30 有研稀土新材料股▲フン▼有限公司 High-coercive force neodymium-iron-boron rare earth permanent magnet and manufacturing process thereof
JP2018082193A (en) * 2017-02-08 2018-05-24 ティアンヘ (パオトウ) アドヴァンスト テック マグネット カンパニー リミテッド Manufacturing method of permanent magnet material
CN108565088A (en) * 2018-05-25 2018-09-21 严高林 A kind of band coating sintered NdFeB magnet and preparation method thereof
CN114783755A (en) * 2022-04-20 2022-07-22 杨杭福 Method for preparing samarium-iron-nitrogen magnet through electric field and thermal field co-assistance
CN114783755B (en) * 2022-04-20 2024-03-05 杨杭福 Method for preparing samarium-iron-nitrogen magnet by electric field thermal field co-assistance

Also Published As

Publication number Publication date
JP4742966B2 (en) 2011-08-10

Similar Documents

Publication Publication Date Title
JP4742966B2 (en) Method for producing R-Fe-B rare earth sintered magnet
JP4765747B2 (en) Method for producing R-Fe-B rare earth sintered magnet
US7824506B2 (en) Nd-Fe-B magnet with modified grain boundary and process for producing the same
JP5206834B2 (en) R-Fe-B rare earth sintered magnet and method for producing the same
JP5158222B2 (en) Rare earth sintered magnet and manufacturing method thereof
JP4241890B2 (en) R-Fe-B rare earth sintered magnet and method for producing the same
JP5509850B2 (en) R-Fe-B rare earth sintered magnet and method for producing the same
JP4811143B2 (en) R-Fe-B rare earth sintered magnet and method for producing the same
JP4677942B2 (en) Method for producing R-Fe-B rare earth sintered magnet
JP5348124B2 (en) Method for producing R-Fe-B rare earth sintered magnet and rare earth sintered magnet produced by the method
JPWO2009016815A1 (en) R-Fe-B rare earth sintered magnet
JP2009043776A (en) R-fe-b-based rare-earth sintered magnet and its manufacturing method
JP2011101043A (en) R-fe-b based rare earth sintered magnet, and method of manufacturing the same
JP2005150503A (en) Method for manufacturing sintered magnet
US20110286878A1 (en) Method for production of ndfebga magnet and ndfebga magnet material
JP5644170B2 (en) Method for producing RTB-based sintered magnet
JP4649591B2 (en) Rare earth alloy manufacturing method
EP1494250B1 (en) Rare earth sintered magnet and method for production thereof
JPH04329804A (en) Production of rare earth alloy powder

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20090305

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20101221

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20110209

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20110412

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20110425

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140520

Year of fee payment: 3

R150 Certificate of patent or registration of utility model

Ref document number: 4742966

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

Free format text: JAPANESE INTERMEDIATE CODE: R150

S531 Written request for registration of change of domicile

Free format text: JAPANESE INTERMEDIATE CODE: R313531

S533 Written request for registration of change of name

Free format text: JAPANESE INTERMEDIATE CODE: R313533

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350