JP5039878B2 - Method for producing rare earth sintered magnet and method for producing rare earth bonded magnet - Google Patents
Method for producing rare earth sintered magnet and method for producing rare earth bonded magnet Download PDFInfo
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- JP5039878B2 JP5039878B2 JP2007245618A JP2007245618A JP5039878B2 JP 5039878 B2 JP5039878 B2 JP 5039878B2 JP 2007245618 A JP2007245618 A JP 2007245618A JP 2007245618 A JP2007245618 A JP 2007245618A JP 5039878 B2 JP5039878 B2 JP 5039878B2
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- 229910052761 rare earth metal Inorganic materials 0.000 title claims description 86
- 150000002910 rare earth metals Chemical class 0.000 title claims description 77
- 238000004519 manufacturing process Methods 0.000 title claims description 23
- 239000000843 powder Substances 0.000 claims description 64
- 238000005245 sintering Methods 0.000 claims description 31
- 229910045601 alloy Inorganic materials 0.000 claims description 21
- 239000000956 alloy Substances 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 19
- 239000002245 particle Substances 0.000 claims description 17
- 238000005121 nitriding Methods 0.000 claims description 16
- 238000010438 heat treatment Methods 0.000 claims description 14
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 12
- 239000011230 binding agent Substances 0.000 claims description 10
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 239000011261 inert gas Substances 0.000 claims description 9
- 239000013078 crystal Substances 0.000 claims description 8
- 125000004433 nitrogen atom Chemical group N* 0.000 claims description 8
- 229910052723 transition metal Inorganic materials 0.000 claims description 8
- 238000000465 moulding Methods 0.000 claims description 7
- 239000011347 resin Substances 0.000 claims description 7
- 229920005989 resin Polymers 0.000 claims description 7
- 239000012298 atmosphere Substances 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 238000000748 compression moulding Methods 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 3
- 238000000227 grinding Methods 0.000 claims description 3
- 238000000265 homogenisation Methods 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 238000001746 injection moulding Methods 0.000 claims description 2
- 239000006247 magnetic powder Substances 0.000 claims description 2
- 238000003801 milling Methods 0.000 claims 1
- 238000007254 oxidation reaction Methods 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- 239000000654 additive Substances 0.000 description 7
- 230000005415 magnetization Effects 0.000 description 7
- 230000003647 oxidation Effects 0.000 description 7
- 238000012545 processing Methods 0.000 description 7
- 230000000996 additive effect Effects 0.000 description 6
- 238000001816 cooling Methods 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 230000001678 irradiating effect Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 229910052779 Neodymium Inorganic materials 0.000 description 3
- 229910052772 Samarium Inorganic materials 0.000 description 3
- -1 SmCo 5 Chemical class 0.000 description 3
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 150000004767 nitrides Chemical class 0.000 description 3
- 238000010298 pulverizing process Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910052777 Praseodymium Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000010891 electric arc Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000007790 solid phase Substances 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- 150000003624 transition metals Chemical class 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052689 Holmium Inorganic materials 0.000 description 1
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 229910000767 Tm alloy Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 238000005280 amorphization Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 239000007822 coupling agent Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 239000001023 inorganic pigment Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical class 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000006082 mold release agent Substances 0.000 description 1
- 229910001172 neodymium magnet Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 229910017464 nitrogen compound Inorganic materials 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 229910000938 samarium–cobalt magnet Inorganic materials 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/105—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/1003—Use of special medium during sintering, e.g. sintering aid
- B22F3/1007—Atmosphere
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/04—Making non-ferrous alloys by powder metallurgy
- C22C1/047—Making non-ferrous alloys by powder metallurgy comprising intermetallic compounds
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
- H01F41/0266—Moulding; Pressing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/105—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding
- B22F2003/1054—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding by microwave
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
- B22F2003/248—Thermal after-treatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
- B22F2998/10—Processes characterised by the sequence of their steps
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C2202/00—Physical properties
- C22C2202/02—Magnetic
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- 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
- H01F1/0555—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together
- H01F1/0557—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together sintered
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- 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
- H01F1/0555—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together
- H01F1/0558—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together bonded together
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- 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
- H01F1/0577—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 sintered
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- 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
- H01F1/0578—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 bonded together
Description
本発明は、希土類系焼結磁石の製造方法及び希土類系ボンド磁石の製造方法に関する。 The present invention relates to a method for producing a rare earth sintered magnet and a method for producing a rare earth bonded magnet.
希土類元素を主成分とする磁石の製造方法は、一般的な焼結方法において合金溶解、熱処理、粉砕、プレス成形、必要に応じて窒化処理を行い、焼結、熱処理、加工、着磁等といった各工程を有する。 The manufacturing method of magnets mainly composed of rare earth elements includes alloy melting, heat treatment, pulverization, press molding, nitriding treatment as necessary in general sintering methods, sintering, heat treatment, processing, magnetization, etc. Each step is included.
又、形状自由度の高く安価に作成できるボンド磁石は、焼結法にて熱処理までの工程を経た磁石を粉砕し、樹脂（エポキシやナイロン等）と混合しコンパウンドを原料として、形状自由度の高く安価に作成できる圧縮成形あるいは射出成形等により製造されている。 Bonded magnets with a high degree of freedom in shape can be made at low cost by crushing magnets that have undergone the process up to heat treatment by a sintering method, mixing them with resin (epoxy, nylon, etc.) Manufactured by compression molding or injection molding which can be produced at high cost.
磁石用材料のＳｍＣｏ５、Ｓｍ２Ｃｏ１７、Ｎｄ２Ｆｅ１４Ｂなどの化合物は、特に重要な焼結工程において、真空、若しくは、Ａｒ等の不活性雰囲気中で炉内のヒーター棒により加熱する大型炉を使用し、熱伝導あるいは輻射熱により昇温、高温維持し、成形品の固相及び液相反応を進行させ、焼結体とする。 Compounds such as SmCo 5 , Sm 2 Co 17 , and Nd 2 Fe 14 B, which are magnet materials, are heated by a heater rod in a furnace in a vacuum or an inert atmosphere such as Ar in a particularly important sintering process. Using a large furnace, the temperature is raised and maintained at a high temperature by heat conduction or radiant heat, and the solid phase and liquid phase reactions of the molded article are advanced to obtain a sintered body.
しかしながら、大型炉では、ヒーターの発熱部近傍と離れた箇所では温度差が発生し、希土類磁石の磁気特性に大きく関わる結晶粒径に影響し磁気特性バラツキを生じる。
この問題に対し、特許文献１には、大型炉を用いない焼結炉の外周囲にコイルを配置した高周波誘導加熱を行い温度分布の均一化を図る方法が記載されている。
However, in a large furnace, a temperature difference occurs at a location away from the vicinity of the heat generating portion of the heater, which affects the crystal grain size that greatly affects the magnetic properties of the rare earth magnet and causes variations in magnetic properties.
In order to solve this problem, Patent Document 1 describes a method of achieving uniform temperature distribution by performing high-frequency induction heating in which a coil is disposed around the outer periphery of a sintering furnace that does not use a large furnace.
一方、磁石用材料の希土類−遷移金属−窒素系などの化合物は、６５０℃以上の高温になると希土類の窒化物とα−Ｆｅに分解してしまい十分な磁気特性が得られず、バルクの状態で使用することが不可能であった。従って、この磁石用材料は、ボンド磁石用磁性粉末に限定されていた。 On the other hand, rare earth-transition metal-nitrogen compounds such as magnet materials are decomposed into rare earth nitrides and α-Fe at high temperatures of 650 ° C. or higher, and sufficient magnetic properties cannot be obtained. It was impossible to use with. Therefore, for the magnet material it has been limited to magnetic powder for bonded magnets.
しかし、この問題に対し、特許文献２には、プラズマ焼結を用いることにより、焼結時間を短縮し、焼結の際に生じる熱分解を最小限に抑える方法が提案されている。
しかし、特許文献１に記載された方法のように、焼結炉の外周囲にコイルを配置した高周波誘導加熱にて加熱処理を行う方法では、大型炉の外周にコイルを配置するのに大掛かりな設備を要し、コイルを冷却するにもコストが掛かり量産向きではなかった。 However, in the method of performing the heat treatment by high frequency induction heating in which the coil is arranged around the outer periphery of the sintering furnace as in the method described in Patent Document 1, it is not necessary to arrange the coil on the outer periphery of the large furnace. It required equipment and cost to cool the coil, which was not suitable for mass production.
また、特許文献２に記載されたプラズマ焼結を用いる方法では、瞬時に焼結はするものの磁石粉末間同士の間でグロー放電が発生し、過剰焼結となり結晶粒径の粗大化を招き所望とする磁気特性を得ることが不可能であった。 In addition, in the method using plasma sintering described in Patent Document 2, a glow discharge occurs between magnet powders even though the sintering is performed instantaneously, resulting in oversintering and coarsening of the crystal grain size. It was impossible to obtain the magnetic characteristics as follows.
このように、上記した各方法には種々の課題があり、また、各方法により焼結された希土類元素−遷移金属系磁石あるいは希土類−遷移金属−窒素系磁石の磁気特性は、未だに理論値よりかなり低い値に留まっており、特に希土類−遷移金属−窒素系の焼結磁石は、量産化されていないのが現状である。 As described above, each method described above has various problems, and the magnetic properties of the rare earth element-transition metal magnet or rare earth-transition metal-nitrogen magnet sintered by each method are still more than theoretical values. The present situation is that the sintered magnet of rare earth-transition metal-nitrogen system has not been mass-produced.
本発明は、上記問題点を解決するためになされたものであって、窒化工程の処理時間を短縮化することができ、焼結しても熱分解しない優れた磁気特性を有する希土類系焼結磁石の製造方法及び希土類系ボンド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 can reduce the processing time of the nitriding step and has a rare earth-based sintering having excellent magnetic properties that does not thermally decompose even when sintered. The object is to provide a method for producing a magnet and a method for producing a rare-earth bonded magnet.
請求項１の発明は、希土類元素−遷移金属系の合金粉末に対し、所定形状の成形品にする成形工程と、前記成形品を、真空又は不活性ガス中においてマイクロ波を照射し、前記合金粉末を焼結する焼結工程とを有し、前記焼結工程では、窒素原子を含む雰囲気下で前記合金粉末に前記マイクロ波が照射され、前記合金粉末における結晶格子間に窒素原子を侵入させる窒化工程を経て、焼結が行われ、前記焼結工程の後に、前記焼結された成形品を不活性ガス中において加熱し、前記窒素原子を前記結晶格子間の安定な場所に移動する均質化処理工程をさらに有することを要旨とする希土類系焼結磁石の製造方法である。 The invention of claim 1 includes a molding step of forming a molded product of a predetermined shape with respect to the rare earth element-transition metal alloy powder, and irradiating the molded product with microwaves in a vacuum or an inert gas. the powder have a sintering step of sintering, in the sintering step, the microwave to the alloy powder in an atmosphere containing nitrogen atoms is irradiated to penetrate the nitrogen atom between the crystal lattices of the alloy powder Sintering is performed through a nitriding step, and after the sintering step, the sintered molded article is heated in an inert gas to move the nitrogen atoms to a stable place between the crystal lattices. It is a manufacturing method of the rare earth-based sintered magnet whose summary is to further include a heat treatment step .
請求項２の発明は、請求項１に記載の希土類系焼結磁石の製造方法において、前記合金粉末に照射するマイクロ波は、１ＧＨｚ以上、３０ＧＨｚ以下であることを要旨とする。 The gist of the invention of claim 2 is that the microwave irradiated to the alloy powder is 1 GHz or more and 30 GHz or less in the method for producing a rare earth sintered magnet according to claim 1 .
請求項３の発明は、請求項１又は２に記載の希土類系焼結磁石の製造方法において、前記合金粉末の平均粒径が、２〜９０μｍであることを要旨とする。
請求項４の発明は、請求項１〜３のいずれか１に記載の希土類系焼結磁石の製造方法において、前記窒化工程では、窒素を含む雰囲気ガスの圧力を０．１〜５ＭＰａにしたことを要旨とする。
The gist of the third aspect of the present invention is that the average particle size of the alloy powder is 2 to 90 μm in the method for producing a rare earth sintered magnet according to the first or second aspect.
The invention of claim 4 is the method for producing a rare earth sintered magnet according to any one of claims 1 to 3 , wherein, in the nitriding step, the pressure of the atmospheric gas containing nitrogen is set to 0.1 to 5 MPa. Is the gist.
請求項５の発明は、請求項１〜４のいずれか１に記載の希土類系焼結磁石の製造方法で製造した希土類系焼結磁石を、化学粉砕あるいは機械粉砕により平均粒径が５〜９０μｍの希土類系磁石粉末にし、その希土類系磁石粉末と樹脂バインダー又は金属バインダーを混合し、圧縮成形若しくは射出成型して希土類ボンド磁石にすることを要旨とする希土類ボンド磁石の製造方法である。 According to a fifth aspect of the present invention, the rare earth sintered magnet produced by the method for producing a rare earth sintered magnet according to any one of the first to fourth aspects has an average particle size of 5 to 90 μm by chemical grinding or mechanical grinding. in rare earth based on the magnet powder, the rare earth-based mixed magnet powder and a resin binder or a metal binder, the method of producing the rare-earth bonded magnet and summarized in that compression molded or injection molded to be a rare earth bonded magnet is there.
請求項１の発明によれば、希土類元素−遷移金属系の合金粉末に対し、所定形状の成形品にする成形工程と、真空又は不活性ガス中において、マイクロ波を照射することにより、希土類磁石粉末による自己発熱、急速加熱及び選択的加熱を行うことができ、試料全体を均一に昇温することができる。 According to the first aspect of the present invention, a rare earth magnet is obtained by irradiating a rare earth element-transition metal alloy powder with a microwave in a vacuum or an inert gas. Self-heating, rapid heating and selective heating with powder can be performed, and the entire sample can be heated uniformly.
このため、希土類磁石粉末を瞬時に焼結固化することができるとともに、処理時間を短縮化することができる。よって、希土類系元素の蒸発量が抑えられ一定組成が得られる。また、試料のみ温度上昇し、試料廻りの温度を制御できるため冷却速度も速く析出物がない磁気特性の高い希土類系焼結磁石が得られる。 For this reason, the rare earth magnet powder can be instantaneously sintered and solidified, and the processing time can be shortened. Therefore, the evaporation amount of the rare earth element is suppressed and a constant composition can be obtained. In addition, since only the sample is heated and the temperature around the sample can be controlled, a rare earth sintered magnet having a high cooling rate and a high magnetic property free from precipitates can be obtained.
また、希土類元素−遷移金属系の合金粉末に対しマイクロ波を照射することによって、合金粉末自身の自己発熱、急速発熱及び選択的加熱を行うことができる。このため、窒化にかかる処理時間を短縮することができる。また、内部まで均一に窒化して、磁気特性の高い希土類磁石を得ることができる。 Further, by irradiating the rare earth element-transition metal alloy powder with microwaves, the alloy powder itself can be self-heated, rapidly heated, and selectively heated. For this reason, the processing time concerning nitriding can be shortened. Further, it is possible to obtain a rare earth magnet having high magnetic properties by nitriding uniformly to the inside.
また、グロー放電発生させることなく瞬時に焼結固化することができるため、希土類系元素の蒸発量が抑えられ一定組成が得られるとともに、α−ＦｅとＳｍＮとに熱分解する前に焼結され、試料廻りの温度も制御できるため冷却速度も速く析出物がない磁気特性の高い希土類系焼結磁石が得られる。 In addition, since it can be sintered and solidified instantly without generating glow discharge, the evaporation amount of rare earth elements can be suppressed and a constant composition can be obtained, and it can be sintered before thermal decomposition into α-Fe and SmN. Moreover, since the temperature around the sample can be controlled, a rare earth-based sintered magnet having a high cooling rate and a high magnetic property free from precipitates can be obtained.
また、均質化処理を行うことで、希土類系焼結磁石の保持力に重要な均一相が得られ、窒素原子を結晶格子間の安定な場所へ移動させることができ、安定した高い希土類系焼結磁石が得られる。 Further, by performing the homogenization treatment, significant homogeneous phase in the holding power of the rare earth sintered magnet is obtained, it is possible to move the nitrogen atom to a stable location between the crystal lattice, high stable A rare earth sintered magnet is obtained.
請求項２の発明によれば、焼結あるいは窒化工程で照射されるマイクロ波は、１ＧＨｚ以上、３０ＧＨｚ以下であるので、グロー放電を発生させることなく瞬時に均一に焼結することができ、更に局所的に窒化されずに固相拡散が優先的に進行してしまうのを抑制するとともに、内部まで均一に窒化することができる。 According to the invention of claim 2 , since the microwave irradiated in the sintering or nitriding step is 1 GHz or more and 30 GHz or less, it can be instantaneously and uniformly sintered without generating glow discharge. The solid phase diffusion can be prevented from preferentially proceeding without being locally nitrided, and the inside can be uniformly nitrided.
請求項３の発明によれば、合金粉末の平均粒径を２〜９０μｍにしたので、希土類磁石粉末の単磁区粒子化、酸化又は過窒化を抑制するとともに、合金粉末を均一に窒化することができる。 According to the invention of claim 3 , since the average particle size of the alloy powder is 2 to 90 μm, it is possible to suppress single-domain particle formation, oxidation or pernitridation of the rare earth magnet powder, and to uniformly nitride the alloy powder. it can.
請求項４の発明によれば、窒化工程での雰囲気を０．１〜５ＭＰａにしたので、合金粉末を均一に窒化できるとともに、過剰な圧力による合金の過窒化によるアモルファス化を防止することができる。 According to the invention of claim 4 , since the atmosphere in the nitriding step is set to 0.1 to 5 MPa, the alloy powder can be uniformly nitrided, and amorphization due to excessive nitriding of the alloy due to excessive pressure can be prevented. .
請求項５の発明によれば、希土類磁石粉末と、樹脂バインダー又は金属バインダーとを用いて希土類ボンド磁石を作製するので、磁気特性の優れたボンド磁石を得ることができる。 According to the invention of claim 5 , since the rare earth bonded magnet is produced using the rare earth magnet powder and the resin binder or the metal binder, a bonded magnet having excellent magnetic properties can be obtained.
本発明の希土類元素−遷移金属系（以下、Ｒ−ＴＭ系という）の希土類系焼結磁石の製造方法について以下に工程毎に説明する。尚、Ｒは希土類元素のうち少なくとも１種若しくは２種以上の元素であり、ＴＭは遷移元素のうち少なくとも１種若しくは２種以上の元素である。
（１）希土類系磁石粉末
本発明のＲ−ＴＭ系合金を構成する希土類元素は、Ｙ（イットリウム）と、ランタノイド元素（Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ及びＬｕ）等を好適に用いることができる。特に、Ｐｒ、ＮｄまたはＳｍを用いると、著しく磁気特性を高めることができる。また、２種以上の希土類元素を組合せることにより、残留磁束密度と保持力を向上させることができる。
A method for producing a rare earth element-transition metal (hereinafter referred to as R-TM) rare earth sintered magnet according to the present invention will be described step by step. Note that R is at least one element or two or more elements among rare earth elements, and TM is at least one or two or more elements among transition elements.
(1) Rare earth magnet powder The rare earth elements constituting the R-TM alloy of the present invention are Y (yttrium) and lanthanoid elements (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy). , Ho, Er, Tm, Yb, and Lu) can be preferably used. In particular, when Pr, Nd or Sm is used, the magnetic properties can be remarkably improved. Moreover, residual magnetic flux density and coercive force can be improved by combining two or more rare earth elements.
具体的には、ＳｍＣｏ５、Ｓｍ２Ｃｏ１７といったＳｍ−Ｃｏ系磁石粉末や、Ｎｄ２Ｆｅ１４Ｂ等のＮｄ−Ｆｅ系磁石粉末を用いることができる。又は、ＳｍおよびＮｄを主とする希土類元素と、Ｆｅを主とする遷移金属と、Ｎを主とする格子間元素とを基本成分とするＳｍ−Ｆｅ−Ｎ，Ｎｄ−Ｆｅ−Ｎ系磁石粉末を用いることができる。又、上記した希土類磁石粉末を２種以上混合してもよい。 Specifically, Sm-Co based magnet powders such as SmCo5 and Sm2Co17 and Nd-Fe based magnet powders such as Nd2Fe14B can be used. Alternatively, Sm—Fe—N, Nd—Fe—N based magnet powder containing rare earth elements mainly composed of Sm and Nd, transition metals mainly composed of Fe, and interstitial elements mainly composed of N. Can be used. Two or more of the rare earth magnet powders described above may be mixed.
以上のＲ−ＴＭ系又はＲ−ＴＭ−Ｎ系の希土類磁石粉末は、一般的な溶解鋳造法の場合、希土類金属及び遷移金属等を所定の配合比で調合して、不活性ガス雰囲気中で高周波溶解する。さらに、得られた合金インゴットを熱処理し、ジョークラッシャー、ジェットミル又はアトライター等の粉砕機で所定の粒度に粉砕して製造する。 The above R-TM or R-TM-N rare earth magnet powder is prepared by mixing rare earth metals and transition metals at a predetermined blending ratio in an inert gas atmosphere in the case of a general melt casting method. High frequency melting. Further, the obtained alloy ingot is heat-treated and pulverized to a predetermined particle size by a pulverizer such as a jaw crusher, a jet mill or an attritor.
この溶解時に、不可避的不純物として、Ｃ、Ｂ等が含まれても特に問題はない。
磁石粉末の粒径としては、平均粒径２〜１５０μｍが好ましい。２μｍ未満では、酸化されやすい他、形成工程も配向時に凝集し磁気特性の向上が得られず、磁気特性が低いものとなる。また、平均粒径が１５０μｍを超える場合には、磁場をかけて磁化方向を揃えながら成形する際に、粒子が所望の磁化方向に向かず、磁気特性の低下を引き起こす。
（２）添加剤
添加剤は、特に限定されないが、界面活性剤、カップリング剤、滑剤、離型剤、難燃剤、安定剤、無機充填剤や顔料等を用いることができる。この添加剤は、金型へ充填するための流動性、磁場をかけて磁化方向を揃えるための滑り性、金型から取り出す際の離型性、成形品のハンドリングを良好するための強度向上、あるいは、焼結体の収縮率を調整するための密度調整を示すものであればよく、複数種類の添加剤を組合わせて用いてもよい。
（３）混合
上記希土類系磁石粉末及び添加剤をアトライター、ヘンシェルミキサー又はＶブレンダー等で混合分散させることにより、成形用磁石粉末を作成することが好ましく良好な磁気特性、特に高配向な希土類焼結磁石を得ることができる。
（４）圧縮成形（成形工程）
磁場を印加するための電磁石を金型に具備したプレス装置を用い、成形用磁石粉末を金型内に充填し、１０ｋＯｅ（エルステッド）以上の磁場中又は無磁場中で、１０ｔｏｎ以上の圧力で圧縮成形する。
There is no particular problem even if C, B, and the like are included as inevitable impurities during the dissolution.
The average particle size of the magnet powder is preferably 2 to 150 μm. If it is less than 2 μm, it is easy to oxidize, and the formation process also aggregates at the time of orientation, so that no improvement in magnetic properties can be obtained, resulting in low magnetic properties. On the other hand, when the average particle diameter exceeds 150 μm, the particles are not directed in the desired magnetization direction when the magnetic field is applied and the magnetization direction is aligned, which causes a decrease in magnetic properties.
(2) Additive The additive is not particularly limited, and surfactants, coupling agents, lubricants, mold release agents, flame retardants, stabilizers, inorganic fillers, pigments, and the like can be used. This additive has fluidity to fill the mold, slipperiness to align the magnetization direction by applying a magnetic field, releasability when taking out from the mold, strength improvement to improve the handling of the molded product, Or what is necessary is just to show the density adjustment for adjusting the shrinkage | contraction rate of a sintered compact, and you may use it combining multiple types of additive.
(3) mixing the rare earth magnet powder and attritor additives, by mixing and dispersing in a Henschel mixer or a V blender or the like, preferably good magnetic properties to create a molding magnet powder, in particular highly oriented rare earth A sintered magnet can be obtained.
(4) Compression molding (molding process)
Using a press machine equipped with an electromagnet for applying a magnetic field in the mold, the molding magnet powder is filled in the mold, and compressed in a magnetic field of 10 kOe (Oersted) or more, or in a non-magnetic field at a pressure of 10 ton or more Mold.
希土類磁石粉末は、１０ｋＯｅ未満になると、磁化方向に向かないため１０ｋＯｅ以上必要である。
（５）焼結
圧縮成形が終了すると、本実施形態では、得られた成形品に対してマイクロ波を照射することで希土類系磁石粉末を焼結させる。このように希土類磁石粉末を選択的且つ急速に自己発熱させることによって、７５０〜１２００℃まで数分で昇温する。希土類磁石粉末の自己発熱により生じた熱によって、磁石粉末は瞬時に焼結する。このとき、試料全体が均一に昇温することにより、未焼結部のない高強度の希土類系焼結磁石を得ることができる。また、マイクロ波照射により数分で所定温度まで昇温することができるので、処理時間を短縮化するとともに合金粉末の酸化、分解を防ぎ不純物の析出を抑制することができる。
When the rare earth magnet powder is less than 10 kOe, it is not suitable for the magnetization direction, and thus it is necessary to have 10 kOe or more.
(5) Sintering When compression molding is completed, in this embodiment, the rare earth magnet powder is sintered by irradiating the obtained molded product with microwaves. In this way, the rare earth magnet powder is selectively and rapidly self-heated to raise the temperature to 750 to 1200 ° C. in a few minutes. The magnet powder is instantaneously sintered by the heat generated by the self-heating of the rare earth magnet powder. At this time, a high-strength rare-earth sintered magnet having no unsintered portion can be obtained by uniformly raising the temperature of the entire sample. In addition, since the temperature can be raised to a predetermined temperature in a few minutes by microwave irradiation, the processing time can be shortened, and oxidation and decomposition of the alloy powder can be prevented and precipitation of impurities can be suppressed.
成形品に照射するマイクロ波は、１ＧＨｚ以上、３０ＧＨｚ以下が好ましい。１ＧＨｚ未満では、アーク放電が生じやすく、３０ＧＨｚよい大きいと、所望する温度以上に加熱されてしまう。雰囲気は、磁石の酸化抑制の観点から、真空又は不活性ガス中がより好ましい。 The microwave applied to the molded product is preferably 1 GHz or more and 30 GHz or less. If it is less than 1 GHz, arc discharge is likely to occur, and if it is as large as 30 GHz, it will be heated above the desired temperature. The atmosphere is more preferably in a vacuum or an inert gas from the viewpoint of suppressing oxidation of the magnet.
さらに、希土類磁石粉末の焼結と同希土類磁石粉末の窒化を同時に行う場合は、窒素０．１〜５ＭＰａの圧力下が好ましい。０．１ＭＰａ未満では、窒化が粒子内部まで侵入せず表面のみに止まり、５ＭＰａを超えると粒子表面において、過剰窒化となる。 Furthermore, when the nitriding sintering the same rare earth magnet powder in the rare-earth magnet powder at the same time, under a pressure of nitrogen 0.1 to 5 M P a is preferable. If it is less than 0.1 M P a, it stops only on the surface without entering nitride the inside particles, in excess the particle surface 5M P a, becomes excessive nitriding.
また、窒化する希土類磁石粉末は、Ｒ−ＴＭ系を主成分とするものが好ましく、Ｓｍ−Ｆｅ系、Ｎｄ−Ｆｅ系等の希土類磁石粉末を用いることができる。
このとき、窒化のみにとどめボンド用磁石粉末として使用することは可能であるが、平均粒径１００μｍ以上になると表面のみの窒化にとどまり、目的とする磁気特性は得られない。そのため、窒素中加圧中において焼結し、熱処理を施すこと（均質化処理工程）により、窒素原子を結晶格子間の安定な場所に移動し、さらに優れた磁気特性を持つＳｍ−Ｆｅ−Ｎ系焼結磁石を得ることができる。
Further, the rare earth magnet powder to be nitrided is preferably composed mainly of R-TM, and rare earth magnet powders such as Sm-Fe and Nd-Fe can be used.
At this time, it is possible to use only as nitriding as a magnet powder for bonding. However, when the average particle size is 100 μm or more, the nitriding is limited to the surface, and the intended magnetic properties cannot be obtained. Therefore, sintering is performed under pressure in nitrogen and heat treatment (homogenization treatment step) is performed to move nitrogen atoms to a stable location between crystal lattices, and Sm—Fe—N having excellent magnetic properties. A system sintered magnet can be obtained.
さらに、このＳｍ−Ｆｅ−Ｎ系焼結磁石を５〜９０μｍの平均粒径まで化学粉砕あるいは機械粉砕をし、樹脂あるいは低融点金属と混合、成形することにより優れた磁気特性を持つボンド用磁石粉末になることは言うまでもない。同様、他材料の希土類磁石粉末に関しても適用できる。
（６）冷却処理
マイクロ波照射を行なった後、希土類系磁石粉末を焼結させた成形品の冷却処理を行う。即ち、マイクロ波の照射を終了すると、希土類磁石粉末自身は迅速に冷却されるものの、多少の酸化は免れない。これに対し、マイクロ波の照射出力を低下さながら、冷却させる方法も試みたが、ある出力以下になると酸化反応が優先的になり僅かであるが磁気特性の低下が見られる。このため、真空引き、或いは窒素、アルゴンガス等の不活性ガス中にて室温まで冷却する必要があり、外部冷却を併用して行うことも場合によって好ましい。
Furthermore, this Sm-Fe-N sintered magnet is chemically or mechanically pulverized to an average particle size of 5 to 90 μm, mixed with a resin or a low melting point metal, and then molded and formed into a bonding magnet having excellent magnetic properties Needless to say, it becomes powder. Similarly, it can be applied with respect to the rare earth magnet powder other materials.
(6) Cooling treatment After performing microwave irradiation, a cooling treatment is performed on the molded product obtained by sintering the rare earth magnet powder. That is, when the microwave irradiation is finished, the rare earth magnet powder itself is rapidly cooled, but some oxidation is inevitable. On the other hand, a method of cooling while reducing the microwave irradiation output was also tried. However, when the output is lower than a certain output, the oxidation reaction is preferential and a slight decrease in magnetic characteristics is observed. For this reason, it is necessary to cool to room temperature in vacuuming or in inert gas, such as nitrogen and argon gas, and it is also preferable depending on the case that it uses external cooling together.
上記実施形態によれば、以下のような効果を得ることができる。
（１）上記実施形態では、希土類磁石粉末及び添加剤からなる混合物を圧縮成形し、成形品にマイクロ波を照射する。これにより、希土類磁石粉末を選択的に自己発熱させ、磁石粉末を焼結させることができるので、試料全体を均一に昇温し、未焼結部分を無くすことにより機械的強度を良好にすることができる。
According to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, a mixture of rare earth magnet powder and additive is compression molded, and the molded product is irradiated with microwaves. As a result, the rare earth magnet powder can be selectively self-heated and the magnet powder can be sintered, so that the whole sample is heated uniformly and the mechanical strength is improved by eliminating the unsintered portion. Can do.
また、未焼結部分を無くして機械的強度を向上することができるため、焼結磁石粉末の希土類磁石材料の量を増やして磁気特性を向上することができる。さらに、希土類磁石粉末の発熱により希土類磁石粉末を瞬時に焼結させることができるため、処理時間を短縮化することができるとともに、長時間加熱を要因とする酸化、分解を防ぎ不純物の析出を抑制することで、磁気特性の低下を防止することができる。
（２）上記実施形態では、希土類磁石粉末を焼結させた成形品を、真空又は不活性ガス中で冷却するので、希土類磁石粉末の酸化を抑制し、良好な磁気特性を維持することができる。
（３）上記実施形態では、成形品に照射されるマイクロ波の周波数を、１ＧＨｚ以上３０ＧＨｚ以下の範囲とする。このため、低周波で発生しやすいアーク放電を抑制することができる。また、周波数が高すぎることにより所望する温度以上に加熱されてしまうことを防止し、成形品を所望の温度範囲に加熱することができる。
（４）上記実施形態では、窒素雰囲気下且つ０．１〜５ＭＰａの加圧下で、成形品に対してマイクロ波を照射することにより、希土類磁石粉末の窒化と希土類磁石粉末の焼結とを同時に行うことを可能とした。このため、窒化工程と焼結とを別に行う場合と比較して、処理時間を短縮化することができる。
（５）上記実施形態では、希土類磁石粉末の平均粒径を、２〜１５０μｍにした。このため、磁石の表面積が大きくなることによる磁石の酸化を抑制するとともに、磁化方向を揃えながら成形する際に粒子を所望の磁化方向に揃えることができる。
Further, since the mechanical strength can be improved by eliminating the unsintered portion, the amount of the rare earth magnet material of the sintered magnet powder can be increased to improve the magnetic properties. Furthermore, since the rare earth magnet powder can be instantly sintered by the heat generation of the rare earth magnet powder, the processing time can be shortened, and oxidation and decomposition caused by heating for a long time can be prevented to prevent precipitation of impurities. By doing so, it is possible to prevent a decrease in magnetic properties.
(2) In the above embodiment, since the molded product obtained by sintering the rare earth magnet powder is cooled in a vacuum or an inert gas, oxidation of the rare earth magnet powder can be suppressed and good magnetic properties can be maintained. .
(3) In the said embodiment, let the frequency of the microwave irradiated to a molded article be the range of 1 GHz or more and 30 GHz or less. For this reason, the arc discharge which is easy to generate | occur | produce at a low frequency can be suppressed. Moreover, it can prevent that it heats more than desired temperature because a frequency is too high, and can heat a molded article to a desired temperature range.
(4) In the above embodiments, under a pressure of nitrogen atmosphere and 0.1 to 5 M P a, by irradiating the microwaves with respect to the molded article, and sintering of nitride and rare earth magnet powder in the rare-earth magnet powder Can be performed simultaneously. For this reason, processing time can be shortened compared with the case where a nitriding process and sintering are performed separately.
(5) In the above embodiment, the average particle size of the rare earth magnet powder is set to 2 to 150 μm. For this reason, while suppressing the oxidation of the magnet by the surface area of a magnet becoming large, when shape | molding, aligning a magnetization direction, it can align a particle | grain to a desired magnetization direction.
尚、上記実施形態の製造方法で製造した希土類系焼結磁石を、化学粉砕あるいは機械粉砕により、例えば平均粒径が５〜９０μｍの稀土類系磁石粉末にする。そして、その稀土類系磁石粉末を、樹脂バインダー（又は金属バインダー）と添加剤とを混合して圧縮成形若しくは射出成型する。そして、その成形品中の樹脂バインダー（又は金属バインダー）を硬化（又は焼結）させて希土類ボンド磁石を製造するようにしてもよい。熱分解しない優れた磁気特性を有する希土類ボンド磁石を製造することができる。 Note that the rare earth-based sintered magnet manufactured by the manufacturing method of the above embodiment is made into rare earth magnet powder having an average particle diameter of, for example, 5 to 90 μm by chemical pulverization or mechanical pulverization. Then, the rare earth magnet powder is compression molded or injection molded by mixing a resin binder (or metal binder) and an additive. And you may make it manufacture the rare earth bond magnet by hardening (or sintering) the resin binder (or metal binder) in the molded article. Rare earth bonded magnets having excellent magnetic properties that are not thermally decomposed can be produced.
Claims (5)
前記成形品を、真空又は不活性ガス中においてマイクロ波を照射し、前記合金粉末を焼結する焼結工程とを有し、
前記焼結工程では、
窒素原子を含む雰囲気下で前記合金粉末に前記マイクロ波が照射され、前記合金粉末における結晶格子間に窒素原子を侵入させる窒化工程を経て、焼結が行われ、
前記焼結工程の後に、前記焼結された成形品を不活性ガス中において加熱し、前記窒素原子を前記結晶格子間の安定な場所に移動する均質化処理工程をさらに有する
ことを特徴とする希土類系焼結磁石の製造方法。 For the rare earth element-transition metal alloy powder, a molding step for forming a molded product of a predetermined shape,
The molded article is irradiated with microwaves in a vacuum or in an inert gas, the alloy powder have a sintering step of sintering,
In the sintering step,
The alloy powder is irradiated with the microwave in an atmosphere containing nitrogen atoms, and after undergoing a nitriding step for allowing nitrogen atoms to penetrate between crystal lattices in the alloy powder, sintering is performed,
After the sintering step, the method further comprises a homogenization treatment step of heating the sintered molded article in an inert gas and moving the nitrogen atoms to a stable place between the crystal lattices. A method for producing a rare earth sintered magnet.
前記合金粉末に照射するマイクロ波は、１ＧＨｚ以上、３０ＧＨｚ以下であることを特徴とする希土類系焼結磁石の製造方法。 In the manufacturing method of the rare earth sintered magnet according to claim 1 ,
The method for producing a rare earth sintered magnet, wherein the microwave applied to the alloy powder is 1 GHz or more and 30 GHz or less.
前記合金粉末の平均粒径が、２〜９０μｍであることを特徴とする希土類系焼結磁石の製造方法。 In the manufacturing method of the rare earth sintered magnet according to claim 1 or 2 ,
The method for producing a rare earth sintered magnet, wherein the alloy powder has an average particle size of 2 to 90 μm.
前記窒化工程では、窒素を含む雰囲気ガスの圧力を０．１〜５ＭＰａにしたことを特徴とする希土類系焼結磁石の製造方法。 In the manufacturing method of the rare earth-based sintered magnet according to any one of claims 1 to 3 ,
In the nitriding step, the pressure of the atmospheric gas containing nitrogen is set to 0.1 to 5 MPa.
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| JP2007245618A JP5039878B2 (en) | 2007-09-21 | 2007-09-21 | Method for producing rare earth sintered magnet and method for producing rare earth bonded magnet |
| US12/283,624 US20090081067A1 (en) | 2007-09-21 | 2008-09-12 | Method of fabricating rare-earth sintered magnet and method of fabricating rare-earth bonded magnet |
| CNA2008101491876A CN101447330A (en) | 2007-09-21 | 2008-09-19 | Method of fabricating rare-earth sintered magnet and method of fabricating rare-earth bonded magnet |
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| JP2008283141A (en) * | 2007-05-14 | 2008-11-20 | Seiko Instruments Inc | Method of manufacturing rare earth magnet powder, and method of manufacturing rare earth bond magnet |
| CN101882504B (en) * | 2009-11-06 | 2014-01-08 | 金浦威恩磁业(上海)有限公司 | Anisotropic rare-earth magnet light wave microwave sintering method |
| CN102294471A (en) * | 2010-06-24 | 2011-12-28 | 曹水秀 | Method for manufacturing Nd-Fe-B permanent magnet |
| JP6003085B2 (en) * | 2012-02-27 | 2016-10-05 | 株式会社ジェイテクト | Magnet manufacturing method |
| US20130266473A1 (en) * | 2012-04-05 | 2013-10-10 | GM Global Technology Operations LLC | Method of Producing Sintered Magnets with Controlled Structures and Composition Distribution |
| KR101641795B1 (en) * | 2014-12-24 | 2016-07-22 | 주식회사 포스코 | Method for manufacturing R-T-B-based sintered magnet |
| CN104942289A (en) * | 2015-07-14 | 2015-09-30 | 长春工业大学 | Method for performing spark plasma sintering on alloy powder particles by adopting sintering aid |
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| US2933386A (en) * | 1956-08-01 | 1960-04-19 | Rca Corp | Method of sintering and nitriding ferrous bodies |
| JP2928605B2 (en) * | 1990-08-06 | 1999-08-03 | 株式会社豊田中央研究所 | Ceramic sintering method |
| JPH0585816A (en) * | 1991-09-30 | 1993-04-06 | Tokin Corp | Production of ni-zn ferrite |
| JPH05135978A (en) * | 1991-11-14 | 1993-06-01 | Seiko Epson Corp | Manufacture of rare earth element magnet |
| GB9217760D0 (en) * | 1992-08-21 | 1992-10-07 | Martinex R & D Inc | Permanent manget material containing a rare-earth element,iron,nitrogen & carbon |
| JP3299118B2 (en) * | 1996-07-11 | 2002-07-08 | 京セラ株式会社 | Ceramic heating equipment |
| US6183689B1 (en) * | 1997-11-25 | 2001-02-06 | Penn State Research Foundation | Process for sintering powder metal components |
| JP3883026B2 (en) * | 1998-09-30 | 2007-02-21 | 独立行政法人科学技術振興機構 | Method for producing titanium nitride |
| EP1037118B1 (en) * | 1999-03-15 | 2006-08-23 | Canon Kabushiki Kaisha | Resin-coated carrier, two-component developer and image forming method |
| JP4709340B2 (en) * | 1999-05-19 | 2011-06-22 | 株式会社東芝 | Bond magnet manufacturing method and actuator |
| JP2001058873A (en) * | 1999-08-20 | 2001-03-06 | Kubota Corp | Titanium diboride ceramics sintered compact and its production |
| JP3951525B2 (en) * | 1999-11-25 | 2007-08-01 | セイコーエプソン株式会社 | Thin-band magnet material, method for producing thin-band magnet material, magnet powder, and rare earth bonded magnet |
| JP2001151575A (en) * | 1999-11-26 | 2001-06-05 | Kyocera Corp | Method of producing aluminum nitride sintered compact |
| JP3797421B2 (en) * | 2001-12-14 | 2006-07-19 | 信越化学工業株式会社 | Manufacturing method of rare earth sintered magnet |
| JP2006156853A (en) * | 2004-11-30 | 2006-06-15 | Tdk Corp | Rare earth magnet |
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