JP5104391B2 - Method for producing rare earth-transition metal-nitrogen based magnet powder, obtained rare earth-transition metal-nitrogen based magnet powder, composition for bonded magnet using the same, and bonded magnet - Google Patents

Method for producing rare earth-transition metal-nitrogen based magnet powder, obtained rare earth-transition metal-nitrogen based magnet powder, composition for bonded magnet using the same, and bonded magnet Download PDF

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JP5104391B2
JP5104391B2 JP2008042410A JP2008042410A JP5104391B2 JP 5104391 B2 JP5104391 B2 JP 5104391B2 JP 2008042410 A JP2008042410 A JP 2008042410A JP 2008042410 A JP2008042410 A JP 2008042410A JP 5104391 B2 JP5104391 B2 JP 5104391B2
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隆士 井関
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Sumitomo Metal Mining Co Ltd
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本発明は、希土類−遷移金属−窒素系磁石粉末の製造方法、得られる希土類−遷移金属−窒素系磁石粉末、及びそれを用いたボンド磁石用組成物、並びにボンド磁石に関し、より詳しくは、還元拡散法による希土類−遷移金属合金の還元拡散反応生成物（以下、還元物ということがある）を安価で安全に崩壊させて、取り扱いが容易な粒径の希土類−遷移金属−窒素系磁石粉末を安定的に生産できる製造方法、及びそれを用いたボンド磁石用組成物、並びにボンド磁石に関する。   The present invention relates to a method for producing a rare earth-transition metal-nitrogen based magnet powder, the resulting rare earth-transition metal-nitrogen based magnet powder, a composition for a bonded magnet using the same, and a bonded magnet. A rare earth-transition metal-nitrogen magnet powder having a particle size that is easy to handle by cheaply and safely disintegrating a reduction-diffusion reaction product of a rare earth-transition metal alloy (hereinafter sometimes referred to as a reductant) by a diffusion method. The present invention relates to a production method capable of stably producing, a composition for a bonded magnet using the same, and a bonded magnet.

近年のさまざまな電気機器類、例えば携帯電話やデジタルカメラ、デジタルビデオなどほとんどの家電製品などは小型化、軽量化、高性能化が要求され、その要求は高まるばかりである。このような小型化、軽量化を実現するためには、永久磁石の小型化、高特性化が重要な課題の一つとなっている。さらに一方ではコスト競争も激しさを増すばかりであり、磁石に要求される事項としは、軽量化、高等性化、さらには価格（安価）が挙げられる。   Various electric appliances in recent years, for example, most home electric appliances such as mobile phones, digital cameras, and digital videos, are required to be smaller, lighter, and higher in performance. In order to realize such downsizing and weight reduction, downsizing and high performance of permanent magnets are one of the important issues. On the other hand, the cost competition is only intensifying, and the items required for the magnet include weight reduction, higher grade, and price (low price).

磁石業界において、価格面では従来から使われているフェライト磁石が最も有利であるとされているが、最大エネルギー積（ＢＨ）ｍａｘが１５〜２０ｋＪ・ｍ−３（数ＭＧＯｅ）と非常に低く、軽量化、高特性化の要求には到底応えきれない。特性面ではフェライトなどの低特性磁石に比較して数１０倍の磁気特性を有する希土類磁石が知られているが、希土類磁石の需要も上記背景のもと伸びており、１９９３年にはフェライト磁石を抜いて使用量が最も多い磁石となっている。
このうちＮｄ−Ｆｅ−Ｂ系焼結磁石は、４４０ｋＪ・ｍ−３（５５ＭＧＯｅ）を超える最大エネルギー積（ＢＨ）ｍａｘを有し、希土類磁石の中でも最も需要が高い磁石の一つである。さらに、理論上、磁石粉末の磁気特性ではＮｄ−Ｆｅ−Ｂ系磁石に並ぶ磁石として、菱面体晶系、六方晶系、正方晶系、又は単斜晶系の結晶構造を有する金属間化合物に窒素を導入した希土類−遷移金属−窒素系磁石粉末が、特に永久磁石材料として優れた磁気特性を有することから注目され、需要を伸ばしている。
例えば、Ｒ−Ｆｅ−Ｎ（Ｒ：Ｙ、Ｔｈ、及び全てのランタノイド元素からなる群の中から選ばれた１種または２種以上）で表される永久磁石（特許文献１参照）、また、六方晶系あるいは菱面体晶系の結晶構造を有するＲ−Ｆｅ−Ｎ−Ｈ（Ｒ：イットリウムを含む希土類元素のうちの少なくとも１種）で表される磁気異方性材料が知られている（例えば、特許文献２参照）。 In the magnet industry, ferrite magnets that are conventionally used are the most advantageous in terms of price, but the maximum energy product (BH) max is as low as 15-20 kJ · m −3 (several MGOe), It is impossible to meet the demands for weight reduction and high performance. In terms of characteristics, rare earth magnets having magnetic characteristics several tens of times that of low-characteristic magnets such as ferrite are known. However, the demand for rare earth magnets is also growing based on the above background. It has become the magnet with the largest amount of use.
Among these, the Nd—Fe—B based sintered magnet has a maximum energy product (BH) max exceeding 440 kJ · m −3 (55 MGOe), and is one of the magnets in the highest demand among rare earth magnets. Theoretically, in terms of the magnetic properties of the magnet powder, as a magnet aligned with an Nd—Fe—B magnet, an intermetallic compound having a rhombohedral, hexagonal, tetragonal, or monoclinic crystal structure is used. Rare earth-transition metal-nitrogen based magnet powder into which nitrogen has been introduced is attracting attention because it has excellent magnetic properties as a permanent magnet material, and the demand is growing.
For example, a permanent magnet represented by R—Fe—N (R: Y, Th, and one or more selected from the group consisting of all lanthanoid elements) (see Patent Document 1), A magnetic anisotropic material represented by R—Fe—N—H (R: at least one of rare earth elements including yttrium) having a hexagonal or rhombohedral crystal structure is known ( For example, see Patent Document 2).

さらに、菱面体晶系、六方晶系、又は正方晶系の結晶構造を有するＴｈ２Ｚｎ１７型、ＴｂＣｕ７型、又はＴｈＭｎ１２型金属間化合物に窒素等を含有させた希土類磁石材料が知られ、これらの磁石材料の磁気特性等を改善するために、種々の添加物を用いることも検討されている。
例えば、六方晶系あるいは菱面体晶系の結晶構造を有するＲ−Ｆｅ−Ｎ−Ｈ−Ｍ（Ｒ：Ｙを含む希土類元素のうちの少なくとも１種；Ｍ：Ｌｉ、Ｎａ、Ｋ、Ｍｇ、Ｃａ、Ｓｒ、Ｂａ、Ｔｉ、Ｚｒ、Ｈｆ、Ｖ、Ｎｂ、Ｔａ、Ｃｒ、Ｍｏ、Ｗ、Ｍｎ、Ｐｄ、Ｃｕ、Ａｇ、Ｚｎ、Ｂ、Ａｌ、Ｇａ、Ｉｎ、Ｃ、Ｓｉ、Ｇｅ、Ｓｎ、Ｐｂ、Ｂｉの元素、及びこれらの元素並びにＲの酸化物、フッ化物、炭化物、窒化物、水素化物、炭酸塩、硫酸塩、ケイ酸塩、塩化物、硝酸塩のうち少なくとも１種）で表される磁石粉末が知られている（特許文献３参照）。
また、六方晶系あるいは菱面体晶系の結晶構造を有するＲ−Ｆｅ−Ｎ−Ｈ−Ｏ−Ｍ（Ｒ：Ｙを含む希土類元素のうちの少なくとも１種；Ｍ：Ｍｇ、Ｔｉ、Ｚｒ、Ｃｕ、Ｚｎ、Ａｌ、Ｇａ、Ｉｎ、Ｓｉ、Ｇｅ、Ｓｎ、Ｐｂ、Ｂｉの元素、及びこれらの元素並びにＲの酸化物、フッ化物、炭化物、窒化物、水素化物のうち少なくとも１種）で表される磁性材料が知られている（特許文献４参照）。 Furthermore, a rare earth magnet material in which nitrogen or the like is contained in a Th 2 Zn 17 type, TbCu 7 type, or ThMn 12 type intermetallic compound having a rhombohedral, hexagonal, or tetragonal crystal structure is known. In order to improve the magnetic properties and the like of these magnet materials, the use of various additives has also been studied.
For example, R—Fe—NHM having a hexagonal or rhombohedral crystal structure (R: at least one of rare earth elements including Y; M: Li, Na, K, Mg, Ca , Sr, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Pd, Cu, Ag, Zn, B, Al, Ga, In, C, Si, Ge, Sn, Pb , Bi, and these elements and R oxides, fluorides, carbides, nitrides, hydrides, carbonates, sulfates, silicates, chlorides, nitrates) Magnet powder is known (see Patent Document 3).
R—Fe—N—H—O—M (R: Y containing at least one rare earth element; M: Mg, Ti, Zr, Cu) having a hexagonal or rhombohedral crystal structure Zn, Al, Ga, In, Si, Ge, Sn, Pb, Bi, and these elements and at least one of oxides, fluorides, carbides, nitrides, and hydrides of R) A magnetic material is known (see Patent Document 4).

これらの希土類−遷移金属−窒素系磁性材料の多くは、保磁力発生機構がニュークリエーションタイプであるため、平均粒径１〜１０μｍの微細な粉末として使用される。この理由は、平均粒径が１０μｍを超えると、必要な保磁力が得られず、ボンド磁石にしたときその表面が粗くなって磁石粉末の脱落が起こりやすくなってしまうためである。ただし、平均粒径が１μｍ未満では、磁石粉末の酸化による発熱やそれに伴う発火、さらにＴｈ２Ｚｎ１７型結晶構造を有する主相の分解による磁気特性の低下が起こるため好ましくないとされている。
このような希土類−遷移金属−窒素系磁性材料は、数μｍ〜数１０μｍを超える平均粒径を有する希土類−遷移金属系の母合金粉末を製造した後、窒素原子を導入するため、窒素やアンモニア、又はこれらと水素との混合ガス雰囲気中で２００〜７００℃に加熱する窒化処理を行い、次いで、上記所定の粒度に微粉化して製造されている。 Many of these rare earth-transition metal-nitrogen based magnetic materials are used as fine powders having an average particle diameter of 1 to 10 μm because the coercive force generation mechanism is a new creation type. This is because if the average particle size exceeds 10 μm, the necessary coercive force cannot be obtained, and when a bonded magnet is used, the surface becomes rough and the magnet powder is likely to fall off. However, if the average particle size is less than 1 μm, heat generation due to the oxidation of the magnet powder, ignition accompanying it, and further deterioration of the magnetic properties due to decomposition of the main phase having a Th 2 Zn 17 type crystal structure are considered undesirable.
Such a rare earth-transition metal-nitrogen based magnetic material is manufactured by producing a rare earth-transition metal-based master alloy powder having an average particle size exceeding several μm to several tens μm, and then introducing nitrogen atoms, so that nitrogen or ammonia Alternatively, it is manufactured by performing nitriding treatment by heating to 200 to 700 ° C. in a mixed gas atmosphere of these and hydrogen, and then pulverizing to the predetermined particle size.

上記ニュークリエーションタイプの磁石よりさらに耐熱性に優れる希土類−遷移金属−窒素系磁石粉末としてアモルファス相と微結晶の二層からなるピニングタイプのＲ−Ｆｅ−Ｍ−Ｎ磁石がある。例えば、一般式ＲαＦｅ（１００−α−β−γ）ＭｎβＮγで表され（Ｒ：希土類元素のうち少なくとも一種、α、β、γは原子％で３≦α≦２０、０．５≦β≦２５、１７≦γ≦２５を満たす）、その主成分が少なくともＦｅ、Ｍｎ、及びＮを成分とする菱面体晶または六方晶の結晶を有した相であるとともに、平均粒径が１０μｍ以上である磁石材料が知られている（特許文献５）。
さらにＭｎ量を少なくするためＭ元素を入れた一般式：ＲａＦｅ（１００−ａ−ｂ−ｃ−ｄ）ＭｎｂＭｃＮｄ（式中、Ｒは希土類元素から選ばれる一種以上、ＭはＮｉ、Ｃｕ、Ｃｏ、Ｃｒ及びＶの群から選ばれる一種以上、ａ、ｂ、ｃ及びｄは原子％であり、ａ、ｂ、ｃ及びｄは、３≦ａ≦２０、０．０１≦ｂ＜０．５、０．０１≦ｃ≦２５、及び１７≦ｄ≦２５を満たす）で表される希土類−遷移金属−窒素系磁石材料が知られている（特許文献６）。
また、還元拡散法では、希土類酸化物粉末、遷移金属粉末、及び還元剤からなる混合物を非酸化性雰囲気下で加熱処理し還元、拡散反応を起こさせる。その後、還元拡散反応生成物は非常に硬く取り扱いずらいため、場合により崩壊させ粉状または小さな塊状にする。例えば、還元物を密閉容器に装入し、密閉容器内を減圧して雰囲気ガスを排出し、水素を充填させて大気圧よりも０．０１〜０．１１ＭＰａ高い圧力とし合金を自己発熱させ、合金が実質的に発熱しなくなるまで水素で大気圧より高くなるように加圧を続けることにより崩壊させ、さらにその崩壊物から還元剤を取り除くために湿式処理し、続いて窒化、微粉砕を行い磁石粉末とする（特許文献７）。 As a rare earth-transition metal-nitrogen based magnet powder that is more excellent in heat resistance than the above nucleation type magnet, there is a pinning type R-Fe-MN magnet composed of two layers of an amorphous phase and a microcrystal. For example, it is represented by the general formula R α Fe (100-α-β-γ) Mn β N γ (R: at least one of rare earth elements, α, β, γ are atomic% 3 ≦ α ≦ 20, 0. 5 ≦ β ≦ 25 and 17 ≦ γ ≦ 25), the main component of which is a phase having rhombohedral or hexagonal crystals having at least Fe, Mn, and N as components, and the average particle size is A magnet material having a size of 10 μm or more is known (Patent Document 5).
Further, a general formula containing M element in order to reduce the amount of Mn: R a Fe (100-abccd) Mn b Mc N d (wherein R is one or more selected from rare earth elements, M Is one or more selected from the group consisting of Ni, Cu, Co, Cr and V, a, b, c and d are atomic%, and a, b, c and d are 3 ≦ a ≦ 20, 0.01 ≦ b <0.5, 0.01 ≦ c ≦ 25, and 17 ≦ d ≦ 25) are known (Patent Document 6).
In the reduction diffusion method, a mixture comprising a rare earth oxide powder, a transition metal powder, and a reducing agent is heated in a non-oxidizing atmosphere to cause reduction and diffusion reactions. Thereafter, the reduction-diffusion reaction product is very hard and difficult to handle, so it is sometimes broken down into a powder or small lump. For example, the reduced product is charged into a sealed container, the inside of the sealed container is depressurized and the atmospheric gas is discharged, and hydrogen is charged to a pressure 0.01 to 0.11 MPa higher than the atmospheric pressure to cause the alloy to self-heat, It is disintegrated by continuing to pressurize with hydrogen until it becomes higher than atmospheric pressure until the alloy does not substantially generate heat, and further wet-treated to remove the reducing agent from the collapsed product, followed by nitriding and fine grinding. Magnet powder is used (Patent Document 7).

上記希土類−遷移金属−窒素系磁性材料の原料として用いられる希土類−遷移金属系母合金粉末は、溶解鋳造法、液体急冷法、還元拡散法等により製造される。
溶解鋳造法では、溶かした合金が固まる際、温度分布ができ組成ずれを起こしてしまい、また溶解鋳造法、液体急冷法では、原料として使用する希土類金属が高価であるため経済的ではない。
一方、還元拡散法では、高価とされる希土類金属を使わずに安価な希土類酸化物を利用できるため、コスト面で有利である。ただし、還元拡散後の還元物は一般的に非常に硬く、通常機械的に粉砕、または水素処理を行い崩壊させる。機械的な粉砕では砕け方にばらつきがあり特性に大きく左右されたり、収率が下がってしまうなどの問題がある。水素処理をする場合は、還元物の水素吸蔵による発熱によって水素雰囲気中で数１００℃になり危険をともなううえ、水素代やそのための設備投資にも非常にコストがかかる。
さらに詳しく還元拡散法について述べる。希土類酸化物粉末、遷移金属粉末、及び還元剤からなる混合物を非酸化性雰囲気下で加熱処理し希土類酸化物を還元剤で還元し、遷移金属中に拡散される。その後、炉冷し該還元物を取り出す。該還元物は非常に硬く取り扱いずらいため、一般的に粉砕または崩壊させ粉状または小さな塊状にする。例えば、還元物を密閉容器に装入し、密閉容器内を減圧して雰囲気ガスを排出し、水素を充填させて大気圧よりも０．０１〜０．１１ＭＰａ高い圧力とし合金を自己発熱させ、合金が実質的に発熱しなくなるまで水素で大気圧より高くなるように加圧を続けることにより崩壊させる（特許文献７）。さらにその崩壊物から還元剤を取り除くために湿式処理し、希土類−遷移金属合金粉末を得る。続いて窒素元素を含むガスを流しながら、数１００℃で窒化を行う。得られた希土類−遷移金属−窒素系合金粉末を場合により、解砕または微粉砕をすることにより磁石粉末が出来上がる。 The rare earth-transition metal master alloy powder used as a raw material for the rare earth-transition metal-nitrogen based magnetic material is produced by a melt casting method, a liquid quenching method, a reduction diffusion method or the like.
In the melt casting method, when the melted alloy is solidified, the temperature distribution is generated and the composition shifts, and the melt casting method and the liquid quenching method are not economical because the rare earth metal used as a raw material is expensive.
On the other hand, the reduction diffusion method is advantageous in terms of cost because inexpensive rare earth oxides can be used without using expensive rare earth metals. However, the reduced product after reductive diffusion is generally very hard and is usually disrupted by mechanical pulverization or hydrogen treatment. Mechanical pulverization has problems such as variations in pulverization, greatly influenced by characteristics, and reduced yield. When hydrogen treatment is performed, the heat generated by occlusion of the reduced product becomes several hundred degrees Celsius in a hydrogen atmosphere, and there is a danger, and the cost of hydrogen and the equipment investment therefor are very expensive.
The reduction diffusion method will be described in more detail. A mixture of the rare earth oxide powder, the transition metal powder, and the reducing agent is heat-treated in a non-oxidizing atmosphere to reduce the rare earth oxide with the reducing agent and diffuse into the transition metal. Thereafter, the furnace is cooled and the reduced product is taken out. Since the reduced product is very hard and difficult to handle, it is generally pulverized or disintegrated into a powder or small lump. For example, the reduced product is charged into a sealed container, the inside of the sealed container is depressurized and the atmospheric gas is discharged, and hydrogen is charged to a pressure 0.01 to 0.11 MPa higher than the atmospheric pressure to cause the alloy to self-heat, The alloy is collapsed by continuing to pressurize with hydrogen so as to be higher than atmospheric pressure until the alloy does not substantially generate heat (Patent Document 7). Further, wet processing is performed to remove the reducing agent from the collapsed material, and a rare earth-transition metal alloy powder is obtained. Subsequently, nitriding is performed at several hundred degrees Celsius while flowing a gas containing nitrogen element. In some cases, the obtained rare earth-transition metal-nitrogen alloy powder is pulverized or pulverized to produce a magnet powder.

溶解鋳造法、液体急冷法などは、原料に高価な希土類金属を用いるため価格を低く抑えることは難しく、それに比較して、還元拡散法は原料に安価な希土類酸化物を使うため有利とされている。しかし、安価な製造方法である還元拡散法においても、上記のような水素処理工程を加えることによりコストアップにつながっている。それは還元物を水素処理するためには水素ガスを多量に使用するためであり、また、爆発性のガスを用いるため危険性も伴う。さらには還元物が水素ガスを吸う際、気温や還元物温度により水素の吸収量が大きく変化し、これにより崩壊性、収率が変わって品質が安定しないなどの問題が生じることもある。このため、コストを低減できるだけでなく安全面にも配慮して水素の使用量を抑えることが望ましく、さらには品質安定性を向上して還元物を崩壊させる工程を確立することは重要な課題となっている。
特開昭６０−１３１９４９号公報 特開平２−５７６６３号公報 特開平６−２７９９１５号公報 特開平３−１５３８５２号公報 特開平８−５５７１２号広報 特開２００５−４２１５６号広報 特開２００４−２０４２８５号公報 In the melt casting method, liquid quenching method, etc., it is difficult to keep the price low because expensive rare earth metals are used as raw materials. In contrast, the reduction diffusion method is advantageous because it uses inexpensive rare earth oxides as raw materials. Yes. However, the reduction diffusion method, which is an inexpensive manufacturing method, also leads to an increase in cost by adding the above-described hydrogen treatment step. This is because a large amount of hydrogen gas is used to treat the reduced product with hydrogen, and there is also a danger because explosive gas is used. Furthermore, when the reductant sucks hydrogen gas, the amount of hydrogen absorbed varies greatly depending on the temperature and the reductant temperature, which may cause problems such as disintegration, yield change, and unstable quality. For this reason, it is desirable not only to reduce costs but also to reduce the amount of hydrogen used in consideration of safety, and to establish a process for improving the quality stability and breaking down the reduced products is an important issue. It has become.
Japanese Patent Laid-Open No. 60-131949 Japanese Patent Laid-Open No. 2-57663 JP-A-6-279915 JP-A-3-153852 JP-A-8-55712 Japanese Laid-Open Patent Publication No. 2005-42156 JP 2004-204285 A

本発明の目的は、上記従来技術の問題点に鑑み、還元拡散法によって磁気特性を下げることなく、水、または、水と水素ガスを用いて、水素ガス使用量を低減して還元物を崩壊させて希土類−遷移金属−窒素系磁石粉末を安価に安全にかつ安定的に生産できる製造方法および、それを用いたボンド磁石用組成物、並びに安価で小型、高特性かつ高耐熱性のボンド磁石を提供することにある。   In view of the above-mentioned problems of the prior art, the object of the present invention is to use water or water and hydrogen gas to reduce the amount of hydrogen gas used and reduce the reduced product without reducing the magnetic properties by the reduction diffusion method. Manufacturing method capable of producing a rare earth-transition metal-nitrogen based magnet powder inexpensively, safely and stably, a composition for a bond magnet using the same, and an inexpensive, small, high characteristic and high heat resistant bond magnet Is to provide.

本発明者は、上記目的を達成するために鋭意研究を重ね、希土類−遷移金属系母合金粉末を還元拡散法により製造する方法において、還元拡散後の還元物を収容した密閉容器に水、または水と水素ガスを供給することにより還元物と水が反応し水素が発生し、この発生した水素が還元物の母合金に吸収されて膨張していく過程で還元物に歪が生じ、同時に母合金同士を溶着させていた還元剤を酸化するので、還元物が容易に崩壊することを見出し、この方法によれば安全かつ低コストで磁気特性を下げることなく希土類−遷移金属−窒素系磁石粉末を製造できることを確認して、本発明を完成するに至った。   In order to achieve the above object, the present inventor has conducted extensive research, and in a method for producing a rare earth-transition metal master alloy powder by a reduction diffusion method, water or a sealed container containing a reduction product after reduction diffusion, or By supplying water and hydrogen gas, the reduced product and water react to generate hydrogen, and the generated hydrogen is distorted in the process of being absorbed and expanded by the reduced product's master alloy. Since the reducing agent used to weld the alloys is oxidized, it is found that the reductant easily disintegrates. According to this method, the rare earth-transition metal-nitrogen based magnet powder is safe and low in cost without deteriorating the magnetic properties. As a result, the present invention has been completed.

すなわち、本発明の第１の発明によれば、遷移金属合金粉末、希土類酸化物粉末、及び該希土類酸化物を還元するための還元剤を混合し、この混合物を非酸化性雰囲気中で加熱焼成して希土類−遷移金属系母合金を含む還元拡散反応生成物を得て、次いで、該反応生成物を水中に投入し崩壊させて、得られた平均粒径が５〜５０μｍである希土類−遷移金属合金粉末を窒化処理することにより、下記の一般式（１）で表される希土類−遷移金属−窒素系磁石粉末を得る製造方法において、
前記還元拡散反応生成物を水に投入して崩壊させる前に、密閉容器に入れ該還元拡散反応生成物の表面に水、または水と水素ガスを供給して、該反応生成物に含まれる過剰な還元剤、及び、希土類−遷移金属系合金粉末表面と反応させ、発生する水素またはこれと供給した水素ガスを希土類−遷移金属系母合金に吸収させ、水素を吸収しながら合金相が膨張し還元拡散反応生成物に歪を生じさせること、及び、該反応生成物中の希土類−遷移金属系母合金同士を溶着させている還元剤を酸化物にすることを特徴とする希土類−遷移金属−窒素系磁石粉末の製造方法が提供される。
ＲｘＦｅ（１００−ｘ−ｙ−ｚ）ＭｙＮｚ ・・・（１）
（式（１）中、Ｒは１種または２種以上の希土類元素、ＭはＣｕ、Ｍｎ、Ｃｏ、Ｃｒ、Ｔｉ、ＮｉおよびＺｒからなる群から選択される１種または２種以上の遷移金属元素を示し、また、ｘ、ｙ、ｚは原子％で、４≦ｘ≦１８、０．３≦ｙ≦２３、１５≦ｚ≦２５を満たす。） That is, according to the first aspect of the present invention, the transition metal alloy powder, the rare earth oxide powder, and the reducing agent for reducing the rare earth oxide are mixed, and the mixture is heated and fired in a non-oxidizing atmosphere. Thus , a reduction diffusion reaction product containing a rare earth-transition metal master alloy is obtained, and then the reaction product is thrown into water to be collapsed. The resulting rare earth-transition having an average particle size of 5 to 50 μm In the production method for obtaining the rare earth-transition metal-nitrogen based magnet powder represented by the following general formula (1) by nitriding the metal alloy powder,
Prior to collapsing by introducing the reducing diffusion reaction product in water, the water on the surface of the placed in a sealed container The reduction diffusion reaction products or by supplying water and hydrogen gas, excess contained in the reaction product Reactive agent and rare earth-transition metal alloy powder surface reacts, and the generated hydrogen or the supplied hydrogen gas is absorbed by the rare earth-transition metal master alloy, and the alloy phase expands while absorbing hydrogen. Rare earth-transition metal, characterized in that a reduction diffusion reaction product is distorted, and a reducing agent in which the rare earth-transition metal master alloy in the reaction product is welded to an oxide. A method for producing a nitrogen-based magnet powder is provided.
R x Fe (100-x- y-z) M y N z ··· (1)
(In the formula (1), R is one or more rare earth elements, M is one or more transition metals selected from the group consisting of Cu, Mn, Co, Cr, Ti, Ni and Zr. Represents an element, and x, y, and z are atomic% and satisfy 4 ≦ x ≦ 18, 0.3 ≦ y ≦ 23, and 15 ≦ z ≦ 25.)

また、本発明の第２の発明によれば、第１の発明において、還元拡散反応生成物を崩壊させる際、密閉容器内への水の供給量が、該反応生成物１ｋｇあたり５〜５００ｍｌであることを特徴とする希土類−遷移金属−窒素系磁石粉末の製造方法が提供される。
また、本発明の第３の発明は、第１の発明において、還元拡散反応生成物を崩壊させる際、密閉容器内への水素の供給量が、該反応生成物１ｋｇあたり４０Ｌ以下であることを特徴とする希土類−遷移金属−窒素系磁石粉末の製造方法が提供される。
また、本発明の第４の発明によれば、第１又は２の発明において、密閉容器内へ水のみを還元拡散反応生成物に供給する場合、供給後に７〜１５時間放置することを特徴とする希土類−遷移金属−窒素系磁石粉末の製造方法が提供される。
また、本発明の第５の発明によれば、第１〜３のいずれかの発明において、密閉容器内へ水と水素ガスを還元拡散反応生成物に供給する場合、水素を供給した後、７〜１０時間放置することを特徴とする希土類−遷移金属−窒素系磁石粉末の製造方法が提供される。
さらに、本発明の第６の発明によれば、第１の発明において、得られた希土類−遷移金属−窒素合金の粗粉末が、さらに微粉砕または解砕されることを特徴とする希土類−遷移金属−窒素系磁石粉末の製造方法が提供される。 According to the second invention of the present invention, in the first invention, when the reduction diffusion reaction product is collapsed, the amount of water supplied into the sealed container is 5 to 500 ml per kg of the reaction product. There is provided a method for producing a rare earth-transition metal-nitrogen based magnet powder.
The third invention of the present invention is that, in the first invention, when the reduction diffusion reaction product is collapsed, the supply amount of hydrogen into the sealed container is 40 L or less per kg of the reaction product. A method for producing a rare earth-transition metal-nitrogen based magnet powder is provided.
According to the fourth invention of the present invention, in the first or second invention, when only water is supplied to the reduced diffusion reaction product into the sealed container, it is left for 7 to 15 hours after the supply. A method for producing a rare earth-transition metal-nitrogen based magnet powder is provided.
According to the fifth invention of the present invention, in any one of the first to third inventions, when water and hydrogen gas are supplied to the reduction diffusion reaction product in the sealed container, after supplying hydrogen, 7 A method for producing a rare earth-transition metal-nitrogen based magnet powder characterized by being allowed to stand for 10 hours is provided.
Further, according to a sixth aspect of the present invention, the rare earth-transition according to the first aspect is characterized in that the obtained coarse powder of the rare earth-transition metal-nitrogen alloy is further pulverized or pulverized. A method for producing metal-nitrogen based magnet powder is provided.

一方、本発明の第７の発明によれば、第１〜６の発明のいずれかの発明に係り、前記の製造方法によって得られ、平均粒径が１〜３０μｍである希土類−遷移金属−窒素系磁石粉末が提供される。
また、本発明の第８の発明によれば、第７の発明に係り、希土類−遷移金属−窒素系磁石粉末に、熱可塑性樹脂または熱硬化性樹脂のいずれかを樹脂バインダーとして配合してなる希土類−遷移金属−窒素系ボンド磁石用組成物が提供される。
さらに、本発明の第９の発明によれば、第８の発明に係り、ボンド磁石用組成物を圧縮成形又は射出成形してなる希土類−遷移金属−窒素系ボンド磁石が提供される。 On the other hand, according to a seventh invention of the present invention, according to any one of the first to sixth inventions, the rare earth-transition metal-nitrogen obtained by the above production method and having an average particle diameter of 1 to 30 μm. A system magnet powder is provided.
Moreover, according to the eighth invention of the present invention, according to the seventh invention, the rare earth-transition metal-nitrogen magnet powder is blended with either a thermoplastic resin or a thermosetting resin as a resin binder. A composition for a rare earth-transition metal-nitrogen based bonded magnet is provided.
Furthermore, according to the ninth aspect of the present invention, there is provided a rare earth-transition metal-nitrogen based bonded magnet according to the eighth aspect, wherein the bonded magnet composition is compression molded or injection molded.

本発明の希土類−遷移金属−窒素系磁石粉末の製造方法によれば、還元拡散後の還元物を収容した密閉容器に水、または、水と水素ガスを供給することにより還元物と水を反応させ、発生した水素で還元物を崩壊させることにより、水素ガスを全く使用しないか、または従来よりも使用量を削減して希土類−遷移金属−窒素系磁石粉末の原料として用いられる希土類−遷移金属系母合金粉末を得ることができる。
これにより得られた希土類−遷移金属系母合金を窒化処理すれば、従来と同等以上の磁気特性を有する希土類−遷移金属−窒素系磁石粉末を安価に安全にかつ安定的に製造できる。さらに、得られた希土類−遷移金属−窒素系磁石粉末に樹脂バインダーを配合したボンド磁石用組成物を用いれば、価格を抑えながら各種機器を小型化、高特性化でき、近年のニーズに応え得る希土類−遷移金属−窒素系ボンド磁石を得ることができ、本発明の工業的価値は極めて大きい。 According to the method for producing a rare earth-transition metal-nitrogen based magnet powder of the present invention, water or water and hydrogen gas are supplied to a sealed container containing the reduced product after reduction diffusion to react the reduced product with water. The rare earth-transition metal used as a raw material for rare earth-transition metal-nitrogen magnet powders by using no hydrogen gas at all, or by reducing the amount used compared to the conventional, by causing the reduced product to decay with the generated hydrogen. A system mother alloy powder can be obtained.
By nitriding the rare earth-transition metal master alloy thus obtained, a rare earth-transition metal-nitrogen magnet powder having a magnetic property equivalent to or higher than that of the prior art can be produced safely and stably at low cost. Furthermore, if the composition for bonded magnets in which the obtained rare earth-transition metal-nitrogen-based magnet powder is blended with a resin binder is used, various devices can be miniaturized and improved in characteristics while keeping prices down, and can meet recent needs. A rare earth-transition metal-nitrogen bond magnet can be obtained, and the industrial value of the present invention is extremely large.

本発明の希土類−遷移金属−窒素系磁石粉末の製造方法、得られる希土類−遷移金属−窒素系磁石粉末、及びこれを用いたボンド磁石用組成物、並びにボンド磁石について、以下に詳細に説明する。   The manufacturing method of the rare earth-transition metal-nitrogen based magnet powder of the present invention, the obtained rare earth-transition metal-nitrogen based magnet powder, the composition for bonded magnet using the same, and the bonded magnet will be described in detail below. .

１．希土類−遷移金属−窒素系磁石粉末の製造方法
本発明の希土類−遷移金属−窒素系磁石粉末の製造方法は、遷移金属合金粉末、希土類酸化物粉末、及び該希土類酸化物を還元するための還元剤を混合し、この混合物を非酸化性雰囲気中で加熱焼成して希土類−遷移金属系母合金を含む還元拡散反応生成物を得て、次いで、該反応生成物を水中に投入し崩壊させて、得られた平均粒径が５〜５０μｍである希土類−遷移金属合金粉末を窒化処理することにより、下記の一般式（１）で表される希土類−遷移金属−窒素系磁石粉末を得る製造方法において、
前記還元拡散反応生成物を水に投入して崩壊させる前に、密閉容器に入れ該還元拡散反応生成物の表面に水、または水と水素ガスを供給して、該反応生成物に含まれる過剰な還元剤、及び、希土類−遷移金属系合金粉末表面と反応させ、発生する水素またはこれと供給した水素ガスを希土類−遷移金属系母合金に吸収させ、水素を吸収しながら合金相が膨張し還元拡散反応生成物に歪を生じさせること、及び、該反応生成物中の希土類−遷移金属系母合金同士を溶着させている還元剤を酸化物にすることによって、該還元拡散反応生成物を崩壊させることを特徴とする。
ＲｘＦｅ（１００−ｘ−ｙ−ｚ）ＭｙＮｚ ・・・（１）
（式（１）中、Ｒは１種または２種以上の希土類元素、ＭはＣｕ、Ｍｎ、Ｃｏ、Ｃｒ、Ｔｉ、ＮｉおよびＺｒからなる群から選択される１種または２種以上の遷移金属元素を示し、また、ｘ、ｙ、ｚは原子％で、４≦ｘ≦１８、０．３≦ｙ≦２３、１５≦ｚ≦２５を満たす。） 1. Method for Producing Rare Earth-Transition Metal-Nitrogen Magnet Powder The method for producing a rare earth-transition metal-nitrogen magnet powder of the present invention includes a transition metal alloy powder, a rare earth oxide powder, and a reduction for reducing the rare earth oxide. Then, the mixture is heated and fired in a non-oxidizing atmosphere to obtain a reduction diffusion reaction product containing a rare earth-transition metal master alloy , and then the reaction product is thrown into water to disintegrate. A method for producing a rare earth-transition metal-nitrogen based magnet powder represented by the following general formula (1) by nitriding the obtained rare earth-transition metal alloy powder having an average particle diameter of 5 to 50 μm In
Prior to collapsing by introducing the reducing diffusion reaction product in water, the water on the surface of the placed in a sealed container The reduction diffusion reaction products or by supplying water and hydrogen gas, excess contained in the reaction product Reactive agent and rare earth-transition metal alloy powder surface reacts, and the generated hydrogen or the supplied hydrogen gas is absorbed by the rare earth-transition metal master alloy, and the alloy phase expands while absorbing hydrogen. causing a strain in the reduction and diffusion reaction product, and, rare earth of the reaction product - reducing agent that is welded to the transition metal-based master alloy together by the oxide, the reduction and diffusion reaction product It is made to collapse.
R x Fe (100-x- y-z) M y N z ··· (1)
(In the formula (1), R is one or more rare earth elements, M is one or more transition metals selected from the group consisting of Cu, Mn, Co, Cr, Ti, Ni and Zr. Represents an element, and x, y, and z are atomic% and satisfy 4 ≦ x ≦ 18, 0.3 ≦ y ≦ 23, and 15 ≦ z ≦ 25.)

（希土類元素）
本発明において、希土類−遷移金属−窒素系磁石粉末は、希土類元素、遷移金属元素、及び窒素から構成されている。希土類−遷移金属−窒素系磁石粉末を構成する主要成分の希土類元素（Ｒ）は、磁気異方性を発現させ、保磁力を発生させる上で本質的な役割を果たす元素である。
希土類元素としては、Ｙを含むランタノイド元素のいずれか１種または２種以上であり、例えば、Ｙ、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、およびＳｍの群から選ばれる少なくとも１種以上の元素が挙げられる。これらの中でも、Ｓｍ及び／又はＮｄが好ましい。また、これらとＥｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、およびＹｂの群から選ばれる少なくとも１種の元素とを組み合わせれば、磁気特性を高めることができる。
希土類−遷移金属−窒素系磁石粉末の希土類元素は、４〜１８原子％、好ましくは５〜１５原子％であることが必要である。４原子％よりも少なければ、合金中に軟磁性相であるα−Ｆｅが多く存在するようになり高い保磁力が得にくくなり、１８原子％を超えると主相となる合金相の体積が減少してしまい飽和磁化が低下するため好ましくない。
希土類元素の中では、特に、Ｓｍが好ましく、Ｓｍが希土類元素の５０原子％以上含むと高い保磁力を持つ材料が得られる。ここで用いる希土類元素は、工業的生産により入手可能な純度でよく、製造上、混入が避けられない元素、例えば、Ｏ、Ｈ、Ｃ、Ａｌ、Ｓｉ、Ｆ、Ｎａ、Ｍｇ、Ｃａ、Ｌｉなどが含まれていても差し支えない。 (Rare earth elements)
In the present invention, the rare earth-transition metal-nitrogen based magnet powder is composed of a rare earth element, a transition metal element, and nitrogen. The rare earth element (R) as a main component constituting the rare earth-transition metal-nitrogen based magnet powder is an element that plays an essential role in developing magnetic anisotropy and generating coercive force.
The rare earth element is one or more of lanthanoid elements including Y, and examples thereof include at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, and Sm. . Among these, Sm and / or Nd are preferable. Further, if these are combined with at least one element selected from the group consisting of Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb, the magnetic properties can be enhanced.
The rare earth element of the rare earth-transition metal-nitrogen based magnet powder needs to be 4 to 18 atomic%, preferably 5 to 15 atomic%. If it is less than 4 atomic%, a large amount of α-Fe, which is a soft magnetic phase, will be present in the alloy, making it difficult to obtain a high coercive force. This is not preferable because the saturation magnetization is lowered.
Among rare earth elements, Sm is particularly preferable, and a material having a high coercive force can be obtained when Sm is contained at 50 atomic% or more of the rare earth element. The rare earth element used here may be a purity that can be obtained by industrial production, and elements that cannot be mixed in production, such as O, H, C, Al, Si, F, Na, Mg, Ca, Li, etc. May be included.

（遷移金属元素）
本発明の希土類−遷移金属−窒素系磁石粉末を構成する主要な遷移金属元素としては、鉄（Ｆｅ成分）が挙げられ、希土類−遷移金属−窒素系磁石粉末の必須成分である。
Ｆｅ成分は、強磁性を担う基本元素であり、希土類−遷移金属−窒素系磁石粉末としたとき、３４〜８１原子％、好ましくは６０〜７５原子％含有する必要がある。Ｆｅ成分が、３４原子％より少ないと磁化が低くなり好ましくない。８１原子％を超えると希土類元素の割合が少なくなり過ぎ、高い保磁力が得られず好ましくない。Ｆｅ成分の組成範囲が６０〜７５原子％であれば、保磁力と磁化のバランスのとれた材料となり特に好ましい。 (Transition metal element)
As a main transition metal element constituting the rare earth-transition metal-nitrogen based magnet powder of the present invention, iron (Fe component) may be mentioned, which is an essential component of the rare earth-transition metal-nitrogen based magnet powder.
The Fe component is a basic element responsible for ferromagnetism, and when it is a rare earth-transition metal-nitrogen based magnet powder, it is necessary to contain 34-81 atomic%, preferably 60-75 atomic%. If the Fe content is less than 34 atomic%, the magnetization is lowered, which is not preferable. If it exceeds 81 atomic%, the proportion of rare earth elements becomes too small, and a high coercive force cannot be obtained, which is not preferable. If the composition range of the Fe component is 60 to 75 atomic%, a material having a balanced coercive force and magnetization is particularly preferable.

（添加元素Ｍ）
Ｍは、Ｍｎ、Ｃｕ、Ｃｏ、Ｃｒ、Ｔｉ、Ｎｉ、Ｚｒ、Ｈｆの少なくとも一種以上を示す元素であり、粗い合金粉末で高い保磁力を出すために必須である。好ましいＭは、Ｍｎ、Ｃｕ、Ｃｒ、Ｔｉであり、特にＭｎが好ましい。
以下、一例としてＳｍ−Ｆｅ−Ｍｎ−Ｎ系磁石を取り上げ説明する。Ｍ元素を添加しＳｍ２（ＦｅＭ）１７Ｎ３の割合よりも過剰に窒素を入れることにより、希土類−遷移金属−窒素系磁石粉末は、粒子内部でＭ元素のはたらきにより部分的にアモルファス化し、その中に数〜数１００ｎｍの結晶が微細に混在した状態になる。このような微結晶構造になると非磁性であるアモルファス部が粒子内の各微結晶間の磁気的な結合を切り、低保磁力の強磁性層に表面を覆われた場合と異なり、粗い粉末であっても高い保磁力が得られる。さらに上記微結晶部は飽和磁化の高いＳｍ２Ｆｅ１７Ｎ３に近い強磁性相となっているため、Ｓｍ−Ｆｅ−Ｍｎ−Ｎ系磁石粉末は粗い合金粉末であっても高い飽和磁化、保磁力が得られる。
Ｍ量は０．３〜２３原子％が好ましい。Ｍが０．３原子％より少ないと結晶性のある部分を残さずに大部分がアモルファス化してしまい磁気特性が低くなってしまう。２３原子％より多いと非磁性相の割合が多くなりすぎ、磁化が低くなってしまう。
添加元素Ｍの効果は、Ｍｎ以外を用いた他のＲｘＦｅ（１００−ｘ−ｙ−ｚ）ＭｙＮｚ で示される磁石においても同様に発揮される。 (Additive element M)
M is an element showing at least one of Mn, Cu, Co, Cr, Ti, Ni, Zr, and Hf, and is essential for producing a high coercive force with a coarse alloy powder. Preferred M is Mn, Cu, Cr, Ti, and Mn is particularly preferred.
Hereinafter, an Sm—Fe—Mn—N-based magnet will be described as an example. By adding M element and adding nitrogen in excess of the ratio of Sm 2 (FeM) 17 N 3 , the rare earth-transition metal-nitrogen based magnet powder is partially amorphized by the action of the M element inside the particles, A few to several hundred nm of crystals are finely mixed therein. In such a microcrystalline structure, the non-magnetic amorphous part breaks the magnetic coupling between the microcrystals in the particle, and unlike the case where the surface is covered with a low coercive force ferromagnetic layer, it is a coarse powder. High coercivity can be obtained even if it exists. Furthermore, since the microcrystalline portion has a ferromagnetic phase close to Sm 2 Fe 17 N 3 having a high saturation magnetization, even if the Sm—Fe—Mn—N based magnet powder is a coarse alloy powder, it has a high saturation magnetization and retention. Magnetic force can be obtained.
The amount of M is preferably 0.3 to 23 atomic%. When M is less than 0.3 atomic%, most of the film becomes amorphous without leaving a crystalline part, and the magnetic properties are lowered. If it is more than 23 atomic%, the proportion of the nonmagnetic phase becomes too high and the magnetization becomes low.
The effect of the additive element M is also exerted in the same manner in other magnets represented by R x Fe (100-xyz) M y N z using materials other than Mn.

（窒素）
窒素は、本発明で得られた希土類−遷移金属系母合金を窒化して、磁石化するために必要な元素であり、１５〜２５原子％、好ましくは１８〜２２原子％含有する必要がある。ピニングタイプの磁石の場合、窒素が１５原子％未満ではアモルファス相が少なすぎ微結晶構造にならず保磁力が高まらず、２５原子％を超えてしまうと非磁性と考えられるアモルファス相が多くなり磁化が下がってしまう。窒素が１８〜２２原子％であれば、アモルファス相が多くなるすぎない範囲で微結晶化が進み特に好ましい。
本発明の希土類−遷移金属−窒素系磁石粉末の製造方法は、希土類酸化物粉末、遷移金属粉末、及び該希土類酸化物を還元するための還元剤を混合し、この混合物を非酸化性雰囲気中で加熱焼成して希土類−遷移金属系母合金を含む還元物とし、次いで、この還元物に水または水と水素ガスを供給して崩壊させた後、該還元物を湿式処理し還元剤を除去し、窒素含有雰囲気中で加熱処理して、希土類−遷移金属系母合金の窒化物とする工程を含んでいる。本発明では、得られた窒化物を必要により微粉砕又は解砕して所定の粒径を有する希土類−遷移金属−窒素系磁石粉末を製造する工程を含むことができる。 (nitrogen)
Nitrogen is an element necessary for nitriding and magnetizing the rare earth-transition metal master alloy obtained in the present invention, and it is necessary to contain 15 to 25 atomic%, preferably 18 to 22 atomic%. . In the case of a pinning type magnet, if the nitrogen content is less than 15 atomic%, the amorphous phase is too small and the microcrystalline structure does not increase and the coercive force does not increase. If the nitrogen content exceeds 25 atomic%, the amorphous phase is considered to be non-magnetic and increases in magnetization. Will go down. If the nitrogen content is 18 to 22 atomic%, it is particularly preferable that microcrystallization proceeds in a range in which the amorphous phase does not increase too much.
The method for producing a rare earth-transition metal-nitrogen based magnet powder according to the present invention comprises mixing a rare earth oxide powder, a transition metal powder, and a reducing agent for reducing the rare earth oxide, and mixing the mixture in a non-oxidizing atmosphere. After heating and firing at a reduced product containing a rare earth-transition metal master alloy, the reduced product is collapsed by supplying water or water and hydrogen gas, and then the reduced product is wet treated to remove the reducing agent. And a heat treatment in a nitrogen-containing atmosphere to form a nitride of a rare earth-transition metal master alloy. The present invention may include a step of producing a rare earth-transition metal-nitrogen based magnet powder having a predetermined particle size by pulverizing or crushing the obtained nitride as necessary.

（希土類−遷移金属合金粉末の製造）
本発明では、還元拡散法により、希土類酸化物粉末、遷移金属粉末、及び該希土類酸化物を還元するための還元剤を混合した後、非酸化性雰囲気中で加熱焼成して、希土類−遷移金属系母合金を含む還元物とする。
さらに詳しくは、還元拡散法では、特定量の希土類酸化物粉末、遷移金属粉末、及び該希土類酸化物を還元するための還元剤を出発原料として用いて、下記に詳述すると同様な条件で加熱焼成して製造する。 (Production of rare earth-transition metal alloy powder)
In the present invention, a rare earth oxide powder, a transition metal powder, and a reducing agent for reducing the rare earth oxide are mixed by a reduction diffusion method and then heated and fired in a non-oxidizing atmosphere to obtain a rare earth-transition metal. A reduced product containing a base mother alloy.
More specifically, in the reduction diffusion method, a specific amount of rare earth oxide powder, transition metal powder, and a reducing agent for reducing the rare earth oxide are used as starting materials and heated under the same conditions as described in detail below. Bake and manufacture.

（希土類酸化物）
希土類酸化物は、前記希土類元素、すなわち、例えば、Ｙ、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、およびＳｍの群から選ばれる少なくとも１種以上の元素の酸化物である。
希土類−遷移金属−窒素系磁石粉末の希土類元素は、前記のとおり、４〜１８原子％であることが必要である。４原子％よりも少なければ、合金中に軟磁性相であるα−Ｆｅが多く存在するようになり高い保磁力が得にくくなり、１８原子％を超えると主相となる合金相の体積が減少してしまい飽和磁化が低下するため好ましくない。
希土類元素の中では、特に、Ｓｍが好ましく、Ｓｍが希土類元素の５０原子％以上含むと高い保磁力を持つ材料が得られる。希土類酸化物原料粉末の平均粒径は、１０μｍ以下、特に５μｍ以下であることが好ましい。
希土類酸化物は、目標組成より２〜２０％程度多く入れることが好ましい。これは希土類の投入量が少ないと還元剤を除去する際の湿式処理時に希土類成分がより多く溶けてしまうため目標組成以下となって希土類が不足し軟磁性相が出現してしまい保磁力を下げてしまうからである。一方、希土類成分が上記範囲より多すぎると非磁性相が多くなり磁化が下がってしまうため好ましくない。 (Rare earth oxide)
The rare earth oxide is an oxide of at least one element selected from the group of the rare earth elements, that is, Y, La, Ce, Pr, Nd, and Sm, for example.
As described above, the rare earth element of the rare earth-transition metal-nitrogen based magnet powder needs to be 4 to 18 atomic%. If it is less than 4 atomic%, a large amount of α-Fe, which is a soft magnetic phase, will be present in the alloy, making it difficult to obtain a high coercive force. This is not preferable because the saturation magnetization is lowered.
Among rare earth elements, Sm is particularly preferable, and a material having a high coercive force can be obtained when Sm is contained at 50 atomic% or more of the rare earth element. The average particle diameter of the rare earth oxide raw material powder is preferably 10 μm or less, particularly preferably 5 μm or less.
It is preferable to add about 2 to 20% more rare earth oxide than the target composition. This is because if a small amount of rare earth is added, more of the rare earth component dissolves during the wet process when removing the reducing agent, so the rare earth is insufficient and the soft magnetic phase appears due to the rare earth composition being reduced and the coercive force is lowered. Because it will end up. On the other hand, if the rare earth component is more than the above range, the nonmagnetic phase increases and the magnetization decreases, which is not preferable.

（遷移金属粉末）
遷移金属粉末としては、鉄、コバルト、或いはニッケルなどが挙げられるが、磁気特性上、鉄が好ましい。鉄は、希土類−遷移金属系合金粉末の必須成分であるが、磁気特性を損なうことなく温度特性や耐食性を改善する目的で、その一部をＣｏまたはＮｉの一種以上で置換してもよい。原料として用いる遷移金属の粒度分布は、目標製品の粒度に近い分布のものを用いることができるが、例えば、平均粒径は１０〜５０μｍであることが好ましい。 (Transition metal powder)
Examples of the transition metal powder include iron, cobalt, and nickel, and iron is preferable in terms of magnetic properties. Iron is an essential component of the rare earth-transition metal alloy powder, but a part thereof may be substituted with one or more of Co or Ni for the purpose of improving temperature characteristics and corrosion resistance without impairing magnetic characteristics. As the particle size distribution of the transition metal used as a raw material, a distribution close to the particle size of the target product can be used. For example, the average particle size is preferably 10 to 50 μm.

（添加元素Ｍの粉末）
Ｍは、Ｍｎ、Ｃｕ、Ｃｏ、Ｃｒ、Ｔｉ、Ｎｉ、Ｚｒ、Ｈｆの少なくとも一種以上を示す元素が挙げられる。原料として用いる添加元素Ｍの粉末の粒度分布は、目標製品の粒度より細かい方が好ましく、例えば、平均粒径は１０μｍ以下であることが好ましい。投入量は、希土類−遷移金属−窒素系磁石粉末の添加元素Ｍが、前記のとおり、０．３〜２３原子％となるようにすることが必要である。 (Additive element M powder)
M is an element showing at least one of Mn, Cu, Co, Cr, Ti, Ni, Zr, and Hf. The particle size distribution of the powder of additive element M used as a raw material is preferably finer than the particle size of the target product. For example, the average particle size is preferably 10 μm or less. The input amount needs to be such that the additive element M of the rare earth-transition metal-nitrogen based magnet powder is 0.3 to 23 atomic% as described above.

（還元剤）
還元剤は、希土類酸化物を還元する機能を有するアルカリ金属又はアルカリ土類金属である。例えばＬｉ及び／又はＣａ、あるいはこれらの元素とＮａ、Ｋ、Ｍｇ、Ｓｒ又はＢａから選ばれる少なくとも１種が使用できる。
これら還元剤は、その投入量と粉体性状、希土類酸化物の粉体性状、各種原料粉末の混合状態、還元拡散反応の温度と時間を注意深く制御して使用することが望ましい。なお、上記還元剤の中では、取り扱いの安全性とコストの点から、金属Ｌｉ又はＣａが好ましく、特にＣａが好ましい。 (Reducing agent)
The reducing agent is an alkali metal or alkaline earth metal having a function of reducing the rare earth oxide. For example, Li and / or Ca, or at least one selected from these elements and Na, K, Mg, Sr or Ba can be used.
These reducing agents are desirably used with carefully controlled amounts and powder properties, powder properties of rare earth oxides, mixed state of various raw material powders, and temperature and time of the reduction diffusion reaction. Among the reducing agents, metal Li or Ca is preferable, and Ca is particularly preferable from the viewpoints of handling safety and cost.

還元剤の投入量は、該希土類酸化物を還元するに足る反応当量よりも過剰とする必要がある。還元剤を当量より過剰にしないと容器内の残存酸素や水分により還元剤が酸化し、希土類酸化物を十分還元できなくなり磁石粉末特性を低下させてしまう。また、得られた還元物に水を供給した際に、十分な水素を発生させることによって還元物を崩壊させることができる量であることが望ましい。   The input amount of the reducing agent needs to be more than the reaction equivalent enough to reduce the rare earth oxide. If the reducing agent is not made more than the equivalent amount, the reducing agent is oxidized by residual oxygen and moisture in the container, and the rare earth oxide cannot be sufficiently reduced, resulting in a decrease in the magnet powder characteristics. Moreover, when water is supplied to the obtained reduced product, it is desirable that the amount of the reduced product can be collapsed by generating sufficient hydrogen.

上記各原料の混合方法は、特に限定されないが、Ｓブレンダー、Ｖブレンダー、各種ミキサー等を用いて行うことができる。例えば、各原料を所定の量、秤量し、Ｖブレンダーで１時間混合すれば良い。
次に、得られた混合物を反応容器に入れる。上記混合物を反応容器に移す際には、希土類酸化物などは平均粒径が数μｍと細かいため粉が飛散しやすい。飛散を防止するためにカバー等を取り付けることが好ましく、これにより合金粉に組成ずれを起こすことが抑制できる。
また、容器内における混合物の状態に特に制限はないが、還元物全体に水がかかり易いような状態にしておくことが望ましい。特に、容器に入れた還元前の混合物に事前に棒状治具等で穴を開けておくことが好ましい。穴の大きさ、深さ、個数などは混合物の量などによっても異なり具体的に規定しにくいが、例えば直径３〜１０ｍｍの棒状治具を容器の底に届くようにほぼ等間隔に設置し、混合物に穴が数箇所から１０箇所程度開くようにすることが好ましい。これにより、焼成後の還元物に水の流路となる穴ができ、水との接触面積が大きくなって、還元物を崩壊しやすくなる。その後、上記混合物を投入した反応容器を還元拡散炉に入れ、酸素が実質的に存在しない非酸化性雰囲気とする。 Although the mixing method of each said raw material is not specifically limited, It can carry out using S blender, V blender, various mixers, etc. For example, each raw material may be weighed in a predetermined amount and mixed with a V blender for 1 hour.
The resulting mixture is then placed in a reaction vessel. When the mixture is transferred to the reaction vessel, the rare earth oxide or the like has a fine average particle size of several μm, so that the powder is easily scattered. In order to prevent scattering, it is preferable to attach a cover or the like, which can suppress a compositional deviation in the alloy powder.
Further, the state of the mixture in the container is not particularly limited, but it is desirable to make the mixture easy to be splashed with water as a whole. In particular, it is preferable to make a hole with a rod-shaped jig or the like in advance in the mixture before reduction placed in a container. The size, depth, number, etc. of the holes vary depending on the amount of the mixture and are difficult to specify specifically. For example, a rod-shaped jig with a diameter of 3 to 10 mm is installed at almost equal intervals so as to reach the bottom of the container, It is preferable that the mixture has several to about 10 holes. Thereby, the hole which becomes a flow path of water is made in the reduced product after baking, the contact area with water becomes large, and the reduced product is easily collapsed. Thereafter, the reaction vessel charged with the mixture is placed in a reduction diffusion furnace to form a non-oxidizing atmosphere substantially free of oxygen.

（還元拡散条件）
上記の原料である遷移金属粉末、希土類酸化物粉末、希土類酸化物を還元する還元剤を配合し、この混合物を非酸化性雰囲気中において、上記還元剤が溶融状態になる温度まで昇温保持し加熱焼成する。
加熱温度は、Ｃａの融点が８３８℃、沸点が１４８０℃であるため、この温度範囲内であれば還元剤は溶解するが、蒸気にはならずに処理することができる。加熱温度は１０００〜１２５０℃とすることが好ましい。これにより、上記希土類酸化物が希土類元素に還元されるとともに、該希土類元素が遷移金属合金粉中に拡散され、希土類−遷移金属系母合金が合成される。得られる還元物は、反応生成物中の希土類−遷移金属系母合金同士を還元剤が溶着させ、還元前の投入原料の形状をほぼ保ちながら還元後収縮した状態の形状となる。希土類−遷移金属系母合金を生成後は、反応容器内を室温まで冷却し取り出す。 (Reduction diffusion condition)
A transition metal powder, a rare earth oxide powder, and a reducing agent for reducing the rare earth oxide, which are the raw materials, are blended, and the mixture is heated to a temperature at which the reducing agent is in a molten state in a non-oxidizing atmosphere. Bake by heating.
As for the heating temperature, since the melting point of Ca is 838 ° C. and the boiling point is 1480 ° C., the reducing agent dissolves within this temperature range, but it can be processed without becoming vapor. The heating temperature is preferably 1000 to 1250 ° C. As a result, the rare earth oxide is reduced to a rare earth element, and the rare earth element is diffused into the transition metal alloy powder to synthesize a rare earth-transition metal master alloy. The resulting reduced product has a shape in which the reducing agent is welded to the rare earth-transition metal master alloy in the reaction product and contracted after reduction while maintaining the shape of the raw material before reduction. After producing the rare earth-transition metal master alloy, the reaction vessel is cooled to room temperature and taken out.

（還元物への水、または、水と水素ガスの供給による崩壊処理）
こうして得られる還元物は非常に硬いうえ、反応容器に溶着しており取り扱いずらい。そこで、還元物を水に投入して崩壊させる前に、水中での崩壊性を改善するために、還元物へ水、または、水と水素ガスを供給することが必要である。 (Disintegration treatment by supplying water or water and hydrogen gas to the reduction product)
The reduced product thus obtained is very hard and is difficult to handle because it is welded to the reaction vessel. In order to improve the disintegration property in water before introducing the reductant into water, it is necessary to supply water or water and hydrogen gas to the reductant.

一例として還元物への水と水素ガスの供給は以下のように行う。まず、上記希土類−遷移金属系母合金の還元物を真空引きできる密閉式のステンレス製容器に入れ、該容器を０．００１ＭＰａ以下まで真空引きし、リークチェックを行う。その後、アルゴンガスを０．１４ＭＰａまで封入し、加圧でのリークチェックを行う。その後、０．００１ＭＰａ以下まで真空引きし容器内の還元物に直接かかるように純水を供給する。水の供給方法は、水が還元物に満遍なく直接かかるような方法であれば特に制限されず、例えば、水をミスト状にして散布したり、スチームとして噴出させたり、あるいは、金網の上に載せた還元物に散水して金網の底部から回収した水を循環して使用したりする方法などがある。水温は特に限定されず、常温でも温水、熱水でもよいが、水素を効果的に発生させるには５０℃以上の温水、熱水が好ましい。この時、水素ガスを加える。この場合、水素はスチームと混合して最初から還元物に供給してもよいし、一旦、純水のみを還元物に供給して、還元物をある程度崩壊させてから水素を供給しても良い。外部から供給される水素の使用量を節約するためには、例えば純水のみを還元物に供給して３〜５時間放置し、還元物をある程度崩壊させてから、水素を供給し容器内圧が０．１〜０．２ＭＰａとなるようにして作用させることが好ましい。   As an example, water and hydrogen gas are supplied to the reduced product as follows. First, the reduced product of the rare earth-transition metal master alloy is put into a sealed stainless steel container that can be evacuated, and the container is evacuated to 0.001 MPa or less to perform a leak check. Thereafter, argon gas is sealed up to 0.14 MPa, and a leak check is performed under pressure. Thereafter, vacuuming is performed to 0.001 MPa or less, and pure water is supplied so as to directly apply to the reduced product in the container. The water supply method is not particularly limited as long as the water is directly applied to the reduced product. For example, the water is sprayed as mist, sprayed as steam, or placed on a wire mesh. There is a method in which the water collected from the bottom of the wire mesh is circulated for use. The water temperature is not particularly limited and may be room temperature, warm water, or hot water, but hot water or hot water of 50 ° C. or higher is preferable in order to effectively generate hydrogen. At this time, hydrogen gas is added. In this case, hydrogen may be mixed with steam and supplied to the reduction product from the beginning, or only pure water may be supplied to the reduction product, and hydrogen may be supplied after the reduction product has collapsed to some extent. . In order to save the amount of hydrogen supplied from the outside, for example, only pure water is supplied to the reductant and left for 3 to 5 hours. It is preferable to make it act so that it may become 0.1-0.2 MPa.

容器内では水と過剰還元剤、希土類−遷移金属系母合金が反応し、発熱しながら水素が発生する。発生した水素と供給した水素ガスは水素吸蔵合金である希土類−遷移金属系母合金に吸収され、希土類リッチ相と主相の膨張率の違い、還元剤の酸化、母合金の表面酸化等により還元物が崩壊する。
水の供給量は、還元物１ｋｇあたり５〜５００ｍｌ、好ましくは１０〜４００ｍｌ、より好ましくは３０〜３００ｍｌとする。過剰に水を供給したとしても粉末の特性やその他の物性値を下げることはないが、還元物１ｋｇあたり５００ｍｌ／ｋｇを超えて水を供給しても反応する過剰還元剤などがなくなり意味がないだけでなく、水分が多いと、還元物が水浸しの状態となり取り出しなどの作業性が悪くなることがある。一方、水の供給量が５ｍｌ／ｋｇ未満では水素発生量が少なすぎて還元物が実質的に崩壊しない。
また、水素の供給量は、還元物１ｋｇあたり４０Ｌ以下、好ましくは３〜３０Ｌである。水素の供給量が還元物１ｋｇあたり３Ｌ未満では還元物を十分に崩壊できない場合があり、一方、４０Ｌを超える水素量は経済的ではない。 In the container, water reacts with the excess reducing agent and the rare earth-transition metal master alloy to generate hydrogen while generating heat. The generated hydrogen and the supplied hydrogen gas are absorbed by the rare earth-transition metal master alloy, which is a hydrogen storage alloy, and reduced by the difference in expansion coefficient between the rare earth-rich phase and the main phase, oxidation of the reducing agent, surface oxidation of the master alloy, etc. Things collapse.
The supply amount of water is 5 to 500 ml, preferably 10 to 400 ml, more preferably 30 to 300 ml per 1 kg of the reduced product. Even if water is supplied in excess, the properties of the powder and other physical properties will not be reduced, but there will be no meaning because there will be no excess reducing agent that reacts even if water is supplied in excess of 500 ml / kg of reduced product. In addition, when there is a lot of water, the reduced product becomes soaked in water, and workability such as removal may deteriorate. On the other hand, when the supply amount of water is less than 5 ml / kg, the amount of hydrogen generated is too small and the reduced product does not substantially collapse.
The supply amount of hydrogen is 40 L or less, preferably 3 to 30 L, per 1 kg of the reduced product. If the supply amount of hydrogen is less than 3 L per kg of the reduced product, the reduced product may not be sufficiently collapsed. On the other hand, the amount of hydrogen exceeding 40 L is not economical.

水と還元剤の反応熱、さらには還元物の水素吸収による発熱により容器内の温度は上がるが、この発熱が実質的に収まり、放熱により容器内温度が４０℃以下になったら還元物を取り出す。
このようにして出来た還元物はすでに過剰還元剤が酸化物になり、希土類−遷移金属合金粉末も表面の酸化が進んでおり、取り出し時に発火する危険性がなく安全に取り扱えるうえ、次工程で水へ投入する際、還元物が水と反応し水素を発生することがなくなるため、安全に処理を行うことができる。さらに還元物を溶着させている過剰還元剤が酸化しているため、水素のみで処理していた従来の場合より還元物が粉状であり非常に取扱いしやすいという長所もある。還元物へ水を供給して発生する水素と供給水素ガスによる崩壊処理を行わずに、いきなり水中へ投入すると、還元物の塊が残り、篩収率が悪く、特性低下にも繋がってしまう。 The temperature inside the container rises due to the heat of reaction between water and the reducing agent, and further due to the heat generated by the absorption of hydrogen in the reduced product. .
The reduced product thus produced has already become an oxide of the excess reducing agent, and the rare earth-transition metal alloy powder has also undergone oxidation on the surface, so there is no risk of ignition when taken out, and it can be handled safely and in the next process. When thrown into water, the reduced product does not react with water to generate hydrogen, so that the treatment can be performed safely. Furthermore, since the excessive reducing agent in which the reduced product is deposited is oxidized, there is an advantage that the reduced product is in a powder form and is very easy to handle than the conventional case where only the hydrogen is treated. When the water is supplied to the reductant and the disintegration process is not performed with hydrogen and supply hydrogen gas, the reductant lump remains, the sieve yield is poor, and the characteristics are deteriorated.

（水中への投入）
次いで、水の供給により崩壊した還元物を水中に投入（水砕）し、デカンテーションにより洗浄し、次いで酸洗、固液分離、乾燥を行い、希土類−遷移金属合金粉末を得る。
水砕では、例えば、得られた粉状還元物を、還元物１ｋｇあたり約１リットルの水の割合で水中に投入し、１〜３時間攪拌し還元物を崩壊させ、スラリー化させる。得られたスラリーは、粗い篩を通し水洗槽に移入する。このときスラリー溶液のｐＨは１１〜１２程度であり、還元物はほとんど崩壊しており、篩上に残るロス分は非常に少なくなり、上記のように還元物に水を供給し、過剰還元剤を酸化させていると、この段階で水と反応し水素を発生することなく安全に作業できる。 (Injection into water)
Next, the reduced product that has been disintegrated by the supply of water is poured into water (granulated), washed by decantation, then pickled, solid-liquid separated, and dried to obtain a rare earth-transition metal alloy powder.
In the water granulation, for example, the obtained powdered reduced product is poured into water at a rate of about 1 liter of water per 1 kg of the reduced product, and stirred for 1 to 3 hours to collapse the reduced product and make a slurry. The obtained slurry is transferred to a water washing tank through a coarse sieve. At this time, the pH of the slurry solution is about 11 to 12, the reduced product is almost collapsed, the amount of loss remaining on the sieve is very small, water is supplied to the reduced product as described above, and the excess reducing agent Can be safely operated without reacting with water and generating hydrogen at this stage.

（水洗、デカンテーション、酸洗）
この後、デカンテーションを５〜１０回程度繰り返す。デカンテーション条件は、例えば、前記スラリー溶液に注水し、攪拌１分、静置分離２分、排水を１回とすることが好ましい。その後、スラリーのｐＨが５〜６になるように酢酸を添加し、酸洗を行うことで固液分離し、固相分を乾燥して希土類−遷移金属合金粉末を得る。還元剤として用いたＣａは非磁性であり、希土類−遷移金属合金粉末の粒界や粒子表面にＣａが存在すると磁気特性を下げるので、できるだけ除去することが好ましい。 (Washing, decantation, pickling)
Thereafter, the decantation is repeated about 5 to 10 times. The decantation conditions are preferably, for example, by pouring water into the slurry solution, stirring for 1 minute, stationary separation for 2 minutes, and draining once. Thereafter, acetic acid is added so that the pH of the slurry is 5 to 6, and pickling is performed for solid-liquid separation, and the solid phase is dried to obtain a rare earth-transition metal alloy powder. Ca used as the reducing agent is non-magnetic, and if Ca is present at the grain boundary or particle surface of the rare earth-transition metal alloy powder, the magnetic properties are lowered.

（窒化処理）
希土類−遷移金属合金粉末を窒化処理するには、予め窒素ガス又はアンモニア、あるいはアンモニア−水素混合ガスのいずれかを含む含窒素雰囲気とした後、特定の温度で加熱を行う。
窒化処理は、該希土類−遷移金属合金粉末を含窒素雰囲気中で、例えば、２００〜７００℃、好ましくは３００〜６００℃、さらに好ましくは３５０〜５５０℃に加熱する方法が採られる。２００℃未満では母合金の窒化速度が遅く、７００℃を超える温度では窒化鉄などを生成してしまうので好ましくない。
また、窒化反応を行う反応装置は、特に限定されず、横型、縦型の管状炉、回転式反応炉、密閉式反応炉などが挙げられる。何れの装置においても、本発明の希土類−遷移金属−窒素系磁石粉末を調製することが可能であるが、特に窒素組成分布の揃った粉体を得るためにはキルンのような回転式反応炉を用いるのが好ましい。 (Nitriding treatment)
In order to nitride the rare earth-transition metal alloy powder, a nitrogen-containing atmosphere containing either nitrogen gas, ammonia, or an ammonia-hydrogen mixed gas is formed in advance, and then heated at a specific temperature.
The nitriding treatment is performed by heating the rare earth-transition metal alloy powder in a nitrogen-containing atmosphere, for example, at 200 to 700 ° C., preferably 300 to 600 ° C., more preferably 350 to 550 ° C. If it is less than 200 ° C., the nitriding rate of the mother alloy is slow, and if it exceeds 700 ° C., iron nitride or the like is generated, which is not preferable.
The reaction apparatus for performing the nitriding reaction is not particularly limited, and examples thereof include horizontal and vertical tubular furnaces, rotary reaction furnaces, and sealed reaction furnaces. In any apparatus, it is possible to prepare the rare earth-transition metal-nitrogen magnet powder of the present invention. In particular, in order to obtain a powder having a uniform nitrogen composition distribution, a rotary reactor such as a kiln. Is preferably used.

窒化を効率よく行うためには、通常１００μｍ程度以下の希土類−遷移金属合金粒子を用いることが好ましい。粒子の大きさは特に制限されないが、凝集・融着部を実質的に含まない平均粒径１０〜５０μｍの粉末であればなお好ましい。このため、希土類−遷移金属合金粉末の凝集・融着部をなくすために、必要により解砕しておくことが好ましく、粒径の大きな希土類−遷移金属合金粉末をさらに微粉化（解砕を含む）して製造してもよい。粒径が１０μｍよりも細かいと発火し易く取り扱いが難しくなる。また、粒径が５０μｍよりも粗いと粒子内を均一に窒化することが行いずらくなり、磁気特性が低くなってしまう。
希土類−遷移金属合金粉末を粉砕、解砕する方法は、特に制限されず、例えば、湿式粉砕法ではボールミル粉砕や媒体攪拌型ミル粉砕等を、乾式粉砕法では不活性ガスによるジェットミル粉砕等を用いることができる。これらの中でも、粉末の凝集を少なくできるジェットミル粉砕が特に好ましい。
また、希土類−遷移金属合金粉末の凝集をさらに少なくするため、例えば、ジェットミル粉砕では、不活性ガス中に５容積％以下の酸素を導入することで微粉化することができる。また、ボールミル粉砕や媒体攪拌ミル粉砕等では、小径の粉砕ボール、あるいはステンレス鋼等ではなくジルコニア等の低比重のセラミックス粉砕ボールを用いることによって微粉化することができる。 In order to efficiently perform nitriding, it is usually preferable to use rare earth-transition metal alloy particles of about 100 μm or less. The size of the particles is not particularly limited, but is more preferably a powder having an average particle size of 10 to 50 μm substantially not including agglomerated / fused portions. For this reason, in order to eliminate the agglomeration / fusion part of the rare earth-transition metal alloy powder, it is preferable that the rare earth-transition metal alloy powder having a larger particle size is further pulverized (including crushing). ) May be manufactured. If the particle size is smaller than 10 μm, it is easy to ignite and handling becomes difficult. On the other hand, if the particle diameter is larger than 50 μm, it is difficult to uniformly nitride the inside of the particles, and the magnetic properties are lowered.
The method for pulverizing and pulverizing the rare earth-transition metal alloy powder is not particularly limited. For example, ball milling or medium stirring mill pulverization is performed in the wet pulverization method, and jet mill pulverization with an inert gas is performed in the dry pulverization method. Can be used. Among these, jet mill pulverization that can reduce aggregation of powder is particularly preferable.
In order to further reduce the aggregation of the rare earth-transition metal alloy powder, for example, in jet mill pulverization, it can be pulverized by introducing 5% by volume or less of oxygen into an inert gas. Further, in ball mill pulverization, medium stirring mill pulverization, etc., fine powder can be obtained by using small-diameter pulverized balls or low-specific gravity ceramic pulverized balls such as zirconia instead of stainless steel.

（窒化処理前の熱処理）
なお、上記希土類−遷移金属合金粉末の粒径が粗大である場合に、粉砕処理を行い得られた母合金粉末には、粉砕により生じた結晶の歪みが残留し、次の窒化工程においてα−Ｆｅ等の軟磁性相が発生する原因となる場合がある。α−Ｆｅ等の軟磁性相が発生すると保磁力や角型性が低下するため、磁気特性を向上させるには、粉砕により得られた母合金微粉末を、窒化処理に先立って、アルゴン、ヘリウム、真空等の非酸化性かつ非窒化性雰囲気中、６００℃以下で熱処理し、結晶の歪みを除去しておくことが好ましい。
特に、窒化処理と同時に４００〜６００℃で熱処理を行うと処理コストを下げられるためメリットが大きい。窒化処理と同時の場合は、熱処理温度が４００℃未満であると、残留する結晶の歪みを除去する効果が十分でなく、一方、６００℃を超えると、窒化鉄などを生成してしまうので好ましくない。 (Heat treatment before nitriding)
When the particle size of the rare earth-transition metal alloy powder is coarse, the mother alloy powder obtained by the pulverization treatment retains the distortion of crystals generated by the pulverization, and α- There are cases where a soft magnetic phase such as Fe is generated. When a soft magnetic phase such as α-Fe is generated, coercive force and squareness are lowered. Therefore, in order to improve magnetic properties, the mother alloy fine powder obtained by pulverization is subjected to argon, helium prior to nitriding treatment. It is preferable to remove crystal distortion by heat treatment at 600 ° C. or lower in a non-oxidizing and non-nitriding atmosphere such as vacuum.
In particular, when the heat treatment is performed at 400 to 600 ° C. simultaneously with the nitriding treatment, the processing cost can be reduced, which is very advantageous. In the case of simultaneous nitriding, if the heat treatment temperature is less than 400 ° C., the effect of removing residual crystal distortion is not sufficient, while if it exceeds 600 ° C., iron nitride or the like is generated, which is preferable. Absent.

（水素アニール、アルゴンアニール）
なお、上記のように、アンモニア−水素混合ガス中で窒化した後の合金粉中には水素が高含有量で残留している場合があり、水素残留量が多いままでは磁気特性が低下するため、必要によって十分に水素を除去しておく必要がある。また、窒素が多すぎると、磁化や保磁力が下がってしまうので、必要によって十分に窒素を除去しておく必要がある。
そのため上記窒化処理の終了後、水素アニール、アルゴンアニールをすることが好ましい。例えば、水素アニールを０．５〜２時間、アルゴンアニールを０．３〜１時間行い、アルゴンを流した状態で室温まで自然または強制冷却をすればよい。
水素アニールは、希土類−遷移金属−窒素系合金主相に過剰に入った窒素を抜きだす効果があり、また、アルゴンアニールは希土類−遷移金属−窒素系合金主相に過剰に入った水素を抜く効果がある。これにより該合金粉末の過剰な窒素、水素が抜け、理論上、最も磁気特性の高い組成に近づかせることができる。 (Hydrogen annealing, argon annealing)
In addition, as described above, hydrogen may remain in a high content in the alloy powder after nitriding in the ammonia-hydrogen mixed gas, and the magnetic characteristics will deteriorate if the hydrogen residual amount remains large. If necessary, it is necessary to remove hydrogen sufficiently. Also, if there is too much nitrogen, the magnetization and coercive force will decrease, so it is necessary to remove nitrogen sufficiently if necessary.
Therefore, it is preferable to perform hydrogen annealing and argon annealing after completion of the nitriding treatment. For example, hydrogen annealing may be performed for 0.5 to 2 hours, argon annealing may be performed for 0.3 to 1 hour, and natural or forced cooling may be performed to room temperature while flowing argon.
Hydrogen annealing has the effect of extracting excess nitrogen in the rare earth-transition metal-nitrogen alloy main phase, and argon annealing removes hydrogen excessive in the rare earth-transition metal-nitrogen alloy main phase. effective. As a result, excess nitrogen and hydrogen in the alloy powder are released, so that the composition can theoretically have the highest magnetic properties.

（解砕又は微粉砕）
解砕または微粉砕を行うことにより、焼結した粉末同士をばらばらにして、さらに高い特性を得ることができる。解砕、微粉砕を行う方法は特に限定されないが、例えば湿式粉砕機、乾式粉砕機、ジェットミル、アトライターなどが挙げられる。アトライターは適当な粉砕溶媒を選択することにより合金粉末を安価に微粉砕できるので好ましい装置といえる。この際、微粉末を乾燥する必要があるが、真空中で乾燥すれば短時間で効率的に乾燥できるので好ましい。 (Crushing or fine grinding)
By performing pulverization or fine pulverization, the sintered powders are separated from each other, and higher characteristics can be obtained. The method for crushing and pulverizing is not particularly limited, and examples thereof include a wet pulverizer, a dry pulverizer, a jet mill, and an attritor. The attritor can be said to be a preferable apparatus because it can finely pulverize the alloy powder at a low cost by selecting an appropriate pulverizing solvent. At this time, it is necessary to dry the fine powder, but drying in vacuum is preferable because it can be efficiently dried in a short time.

２．希土類−遷移金属−窒素系磁石粉末
このようにして得られる本発明の希土類−遷移金属−窒素系磁石粉末は、次の一般式（１）で表される希土類−遷移金属−窒素系合金からなるニュークリエーションタイプの磁石粉末である。
ＲｘＦｅ（１００−ｘ−ｙ−ｚ）ＭｙＮｚ ・・・（１）
（式（１）中、Ｒは１種または２種以上の希土類元素、ＭはＣｕ、Ｍｎ、Ｃｏ、Ｃｒ、Ｔｉ、ＮｉおよびＺｒからなる群から選択される１種または２種以上の遷移金属元素を示し、また、ｘ、ｙ、ｚは原子％で、４≦ｘ≦１８、０．３≦ｙ≦２３、１５≦ｚ≦２５を満たす。）
この希土類−遷移金属−窒素系磁石粉末の平均粒径は、磁気特性上、１〜３０μｍであることが好ましい。 2. Rare earth-transition metal-nitrogen based magnet powder The rare earth-transition metal-nitrogen based magnet powder of the present invention thus obtained comprises a rare earth-transition metal-nitrogen based alloy represented by the following general formula (1). New creation type magnet powder.
R x Fe (100-x- y-z) M y N z ··· (1)
(In the formula (1), R is one or more rare earth elements, M is one or more transition metals selected from the group consisting of Cu, Mn, Co, Cr, Ti, Ni and Zr. Represents an element, and x, y, and z are atomic% and satisfy 4 ≦ x ≦ 18, 0.3 ≦ y ≦ 23, and 15 ≦ z ≦ 25.)
The average particle size of the rare earth-transition metal-nitrogen magnet powder is preferably 1 to 30 μm in view of magnetic characteristics.

（磁石粉末の表面処理）
得られた希土類−遷移金属−窒素系磁石粉末は、空気中、温度や湿度の高い雰囲気中に置かれると錆びたり劣化したりして磁気特性が低下する場合があるため、燐酸や有機燐酸エステル系化合物、亜鉛などの金属粉末、シリルイソシアネート系化合物、シリケート系化合物、あるいはチタネート系、アルミニウム系、シラン系など各種カップリング剤によって表面処理することが望ましい。
例えば、希土類−鉄−マンガン−窒素系磁石粉末に亜鉛粉末とカップリング剤を加えたものを、有機溶媒を媒液として湿式粉砕することができる。磁石粉末の粉砕時に亜鉛粉末及びカップリング剤が存在すると、粉砕された磁石粉末表面にカップリング剤及び亜鉛粉末がコ−ティングされ、粒子同士の付着が防止されて粉砕速度が早くなる。また、亜鉛粉末がコ−ティングされることにより、磁石粉末表面近傍の変質層が磁気的に無害なものになるため、高磁気特性が得られる。また、表面処理剤として有機燐酸エステル系化合物あるいはシリルイソシアネート系化合物を用いる場合、被覆または塗布手段は特に限定されないが、例えば、まず処理剤を磁性粉１００重量部に対して約５〜１０重量部の溶媒に溶解した後、磁性粉と充分に混合撹拌し、２４時間以上真空または減圧乾燥することにより行うことができる。この時、溶媒としては、アルコール類、ケトン類、低級炭化水素類、芳香族類、またはこれらの混合系有機溶媒等が用いられる。 (Surface treatment of magnet powder)
Since the obtained rare earth-transition metal-nitrogen based magnet powder may be rusted or deteriorated when placed in air or in an atmosphere with high temperature and humidity, the magnetic properties may deteriorate. It is desirable that the surface treatment is performed using a metal compound such as a metal compound, zinc, a silyl isocyanate compound, a silicate compound, or various coupling agents such as titanate, aluminum, and silane.
For example, a material obtained by adding a zinc powder and a coupling agent to a rare earth-iron-manganese-nitrogen based magnet powder can be wet pulverized using an organic solvent as a medium. If the zinc powder and the coupling agent are present during the pulverization of the magnet powder, the coupling agent and the zinc powder are coated on the surface of the pulverized magnet powder, the adhesion between the particles is prevented, and the pulverization speed is increased. In addition, since the zinc powder is coated, the altered layer near the surface of the magnet powder becomes magnetically harmless, so that high magnetic characteristics can be obtained. Further, when an organic phosphate ester compound or a silyl isocyanate compound is used as the surface treatment agent, the coating or coating means is not particularly limited. For example, first, the treatment agent is about 5 to 10 parts by weight with respect to 100 parts by weight of the magnetic powder. After being dissolved in the above solvent, the mixture can be sufficiently mixed and stirred with the magnetic powder and dried in a vacuum or under reduced pressure for 24 hours or more. At this time, alcohols, ketones, lower hydrocarbons, aromatics, or mixed organic solvents thereof are used as the solvent.

３．ボンド磁石用組成物
本発明のボンド磁石用組成物は、上記製造方法により得られた希土類−遷移金属−窒素系磁石粉末に、熱可塑性樹脂または熱硬化性樹脂のいずれかを樹脂バインダーとして配合したものである。すなわち、前記した本発明の希土類−遷移金属−窒素系磁石粉末は、バインダー成分として熱可塑性樹脂または熱硬化性樹脂のいずれかを配合し、混合することにより、優れた特性を有するボンド磁石用組成物となる。 3. Composition for Bond Magnet The composition for bond magnet of the present invention was blended with either a thermoplastic resin or a thermosetting resin as a resin binder in the rare earth-transition metal-nitrogen based magnet powder obtained by the above production method. Is. That is, the rare earth-transition metal-nitrogen based magnet powder of the present invention described above is a bonded magnet composition having excellent characteristics by blending and mixing either a thermoplastic resin or a thermosetting resin as a binder component. It becomes a thing.

熱可塑性樹脂としては、４−６ナイロン、１２ナイロンなどのポリアミド系樹脂、ポリオレフィン系樹脂、ポリスチレン樹脂、ポリビニル系樹脂、アクリル系樹脂、アクリロニトリル系樹脂、ポリウレタン系樹脂、ポリエーテル系樹脂、ふっ素樹脂、ポリエチレン樹脂、ポリフェニレンサルファイド樹脂、塩化ビニル樹脂、ポリカーボネート樹脂、ポリスルホン樹脂、酢酸ビニル樹脂、ＡＢＳ樹脂、アクリル樹脂、ポリエーテルエーテルケトンなどを用いることができる。
また、熱硬化性樹脂としては、エポキシ樹脂、フェノール樹脂、不飽和ポリエステル樹脂、キシレン樹脂、ユリア樹脂、メラニン樹脂、熱硬化型シリコーン樹脂、アルキド樹脂、フラン樹脂、熱硬化型アクリル樹脂、熱硬化型フッ素樹脂、ユリア樹脂、ジアリルフタレート樹脂、ポリウレタン樹脂、ケイ素樹脂などを用いることができる。
さらに、バインダー成分の種類にもよるが、重合禁止剤、低収縮化剤、反応性樹脂、反応性希釈剤、未反応性希釈剤、変性剤、増粘剤、滑剤、カップリング剤、離型剤、紫外線吸収剤、難燃剤、安定剤、無機充填剤や顔料などを添加することができる。
本発明のボンド磁石用組成物を調製する際に用いられる混合機としては、特に制限がなく、リボンミキサー、Ｖ型ミキサー、ロータリーミキサー、ヘンシェルミキサー、フラッシュミキサー、ナウターミキサー、タンブラー等が挙げられる。また、回転ボールミル、振動ボールミル、遊星ボールミル、ウェットミル、ジェットミル、ハンマーミル、カッターミル等を用いることができる。各成分を粉砕しながら混合する方法も有効である。 Examples of thermoplastic resins include polyamide resins such as 4-6 nylon and 12 nylon, polyolefin resins, polystyrene resins, polyvinyl resins, acrylic resins, acrylonitrile resins, polyurethane resins, polyether resins, fluorine resins, Polyethylene resin, polyphenylene sulfide resin, vinyl chloride resin, polycarbonate resin, polysulfone resin, vinyl acetate resin, ABS resin, acrylic resin, polyether ether ketone, and the like can be used.
In addition, as the thermosetting resin, epoxy resin, phenol resin, unsaturated polyester resin, xylene resin, urea resin, melanin resin, thermosetting silicone resin, alkyd resin, furan resin, thermosetting acrylic resin, thermosetting resin Fluorine resin, urea resin, diallyl phthalate resin, polyurethane resin, silicon resin, or the like can be used.
Furthermore, depending on the type of binder component, polymerization inhibitor, low shrinkage agent, reactive resin, reactive diluent, unreactive diluent, modifier, thickener, lubricant, coupling agent, mold release An agent, an ultraviolet absorber, a flame retardant, a stabilizer, an inorganic filler, a pigment, and the like can be added.
The mixer used for preparing the composition for bonded magnets of the present invention is not particularly limited, and examples thereof include a ribbon mixer, a V-type mixer, a rotary mixer, a Henschel mixer, a flash mixer, a nauter mixer, and a tumbler. . Further, a rotating ball mill, a vibration ball mill, a planetary ball mill, a wet mill, a jet mill, a hammer mill, a cutter mill, or the like can be used. A method of mixing each component while pulverizing is also effective.

４．ボンド磁石
本発明のボンド磁石は、上記ボンド磁石用組成物を圧縮成形又は射出成形してなる希土類−遷移金属−窒素系ボンド磁石である。すなわち、上記希土類−遷移金属−窒素系磁石粉末を含むボンド磁石用組成物は、混練後、下記の要領で成形してボンド磁石とすることができる。 4). Bond magnet The bond magnet of the present invention is a rare earth-transition metal-nitrogen bond magnet formed by compression molding or injection molding the above-described composition for bonded magnets. That is, the composition for bonded magnets containing the rare earth-transition metal-nitrogen based magnet powder can be formed into a bonded magnet after being kneaded and then molded in the following manner.

上記熱硬化性樹脂を配合したボンド磁石用組成物を用いる場合は、圧縮成形または射出成形によることが好ましい。圧縮成形の場合は、得られるボンド磁石全重量に対する樹脂量としては１〜５重量％、射出成形では、樹脂粘度の調整や金型の温度等の最適条件を選択する必要があるが、７〜１５重量％が好ましい。
圧縮成形する場合は、前記混合比で、例えば、混合機（例えば、井上製作所（製））で混合し、金型に磁界を印加するための電磁石を具備したプレス装置を用い、金型に８００ｋＡ／ｍ（１０ｋＯｅ）以上の磁界を印加しながら、４ｔｏｎ／ｃｍ２の圧力でプレス成形する。
また、射出成形の場合では、前記混合比で加熱加圧ニーダー装置を用いて混合し、金型に磁界を印加するための電磁石を具備したプレス装置を用いて成形する。組成物を、例えば、３０〜８０℃の成形温度に加温したシリンダー中で溶融し、８００ｋＡ／ｍ（１０ｋＯｅ）以上の磁界が印加された金型中に射出成形して、樹脂の硬化温度まで加熱し、一定時間保持して硬化させる。 When using the composition for bonded magnets which mix | blended the said thermosetting resin, it is preferable by compression molding or injection molding. In the case of compression molding, the amount of resin relative to the total weight of the bond magnet to be obtained is 1 to 5% by weight. In the case of injection molding, it is necessary to select optimum conditions such as adjustment of the resin viscosity and the temperature of the mold. 15% by weight is preferred.
In the case of compression molding, the mixing ratio is, for example, mixed with a mixer (for example, manufactured by Inoue Seisakusho Co., Ltd.), and a press apparatus equipped with an electromagnet for applying a magnetic field to the mold is used. / M (10 kOe) or more, press forming at a pressure of 4 ton / cm 2 while applying a magnetic field of more than 10 mOe.
Further, in the case of injection molding, mixing is performed using a heat and pressure kneader device at the above mixing ratio, and molding is performed using a press device provided with an electromagnet for applying a magnetic field to the mold. The composition is melted in, for example, a cylinder heated to a molding temperature of 30 to 80 ° C., and injection-molded into a mold to which a magnetic field of 800 kA / m (10 kOe) or more is applied until the resin curing temperature is reached. Heat and hold for a certain time to cure.

一方、熱可塑性樹脂を配合したボンド磁石用組成物を用いる場合は、射出成形によることが好ましく、樹脂量としては５〜２０重量％が好ましい。熱可塑性樹脂を配合したボンド磁石用組成物は、溶融温度、例えば２１０℃以上に加温したシリンダー中で組成物を溶融し、８００ｋＡ／ｍ（１０ｋＯｅ）以上の磁界が印加された金型中に射出成形し、冷却後、固化した成形物を取り出せば良い。   On the other hand, when using the composition for bond magnets which mix | blended the thermoplastic resin, it is preferable by injection molding and 5 to 20 weight% is preferable as resin amount. The composition for a bonded magnet containing a thermoplastic resin is melted in a cylinder heated to a melting temperature, for example, 210 ° C. or higher, and placed in a mold to which a magnetic field of 800 kA / m (10 kOe) or more is applied. What is necessary is just to take out the solidified molding after injection molding and cooling.

次に実施例、比較例を用いて本発明をさらに説明するが、本発明はこれらの実施例によって何ら限定されるものではない。   EXAMPLES Next, although this invention is further demonstrated using an Example and a comparative example, this invention is not limited at all by these Examples.

＜磁気特性評価＞
希土類−遷移金属−窒素系磁石粉末試料の磁気特性は、次のように測定した。まず、パラフィンを詰めたサンプルケースを準備し、それに磁石粉末を詰め、その後、加熱配向、冷却固化を行い、振動試料型磁力計（ＶＳＭ）（東英工業（株）製）を用い、ヒステリシスループを描かせた（最大印加磁場１１９０ｋＡ／ｍ（１５ｋＯｅ））。
射出成形ボンド磁石に関しては、ｃｉｏｆｆｉ型自記磁束計（東英工業（株）製）を用いて磁気特性を測定した。
＜平均粒径の測定＞
磁石粉末の平均粒径は、レーザー回折式粒度分布計（Ｓｙｍｐａｔｅｃ社製）を用いて測定した。 <Evaluation of magnetic properties>
The magnetic properties of the rare earth-transition metal-nitrogen based magnet powder sample were measured as follows. First, prepare a sample case filled with paraffin, and then fill it with magnet powder, then heat orientation and cooling and solidification, and use a vibrating sample magnetometer (VSM) (manufactured by Toei Kogyo Co., Ltd.), hysteresis loop (Maximum applied magnetic field 1190 kA / m (15 kOe)).
Regarding the injection-molded bonded magnet, the magnetic properties were measured using a cioffi type self-recording magnetometer (manufactured by Toei Kogyo Co., Ltd.).
<Measurement of average particle size>
The average particle diameter of the magnet powder was measured using a laser diffraction particle size distribution meter (manufactured by Sympatec).

（実施例１〜３、比較例１〜３）
次に示す製造方法でＳｍ−Ｆｅ−Ｍｎ−Ｎ合金磁石粉末を作製した。まず、出発原料として、Ｆｅ粉（純度９９．０原子％以上）、Ｍｎ２Ｏ３（純度９９．０原子％以上）、Ｓｍ２Ｏ３（９９．０原子％以上）を準備した。上記原料に還元剤としてＳｍ２Ｏ３、Ｍｎ２Ｏ３を十分に還元できるように過剰量のＣａ（純度９９．３％以上）を加え、混合機で１時間混合した。得られた混合物を反応容器に入れ水が浸透しやすくなるように穴を等間隔に開けた後、さらに還元拡散容器に移した後、電気炉（還元拡散炉）に装入し、アルゴン置換した後、アルゴン流量０．５〜１Ｌ／分として、１２００℃で８時間保持し、Ｓｍ２Ｏ３、Ｍｎ２Ｏ３を還元しＦｅ中に拡散させＳｍ−Ｆｅ−Ｍｎ合金の還元物を製造した。
実施例１では還元物１０ｋｇを真空引きできるステンレス製容器に入れ、０．００１ＭＰａまで真空引きしたのち、還元物に直接かかるように純水を２３０ｃｃ／ｋｇ（還元物１ｋｇに対し純水２３０ｇ）入れ、還元物を水と反応させ１２時間放置した。
実施例２では還元物１０ｋｇを真空引きできるステンレス製容器に入れ、０．００１ＭＰａまで真空引きしたのち、還元物に直接かかるように純水を５２ｃｃ／ｋｇ入れ、還元物を水と反応させ４時間放置し、その後、容器内圧が０．１１〜０．１４ＭＰａになるように水素ガスを流し（水素量８Ｌ／ｋｇ）、８時間水素崩壊させた。
比較例１では還元拡散条件を１３００℃−１２時間とし、水、水素ガスによる崩壊処理を行わなかった。
比較例２では実施例１と同様の還元拡散条件で行い、水での崩壊処理を行わず、真空引き次いでアルゴン置換ののち、さらに真空引きを行い、容器内圧が０．１１〜０．１４ＭＰａになるように水素ガスを流し、１２時間水素崩壊させた。
その後、実施例１、２、比較例１、２の還元物それぞれ１ｋｇ対し水が１０Ｌ入っている水槽に入れ、１０分攪拌後、上澄みを抜き、この作業を１０回繰り返してＣａを除去し、酢酸を用いて酸洗処理を行った。その後、アルコールでデカンテーションし、真空中１００℃、５時間乾燥し、Ｓｍ−Ｆｅ−Ｍｎ母合金粉を得た。
次に、得られた母合金粉末を、アンモニア−水素混合ガス中、４８０℃で８時間窒化処理、その後、水素アニール、窒素アニールを行い、Ｓｍ−Ｆｅ−Ｍｎ−Ｎ粗粉を製造した。
さらに実施例１で得られた磁石粗粉（試料）１ｋｇをアトライター（三井鉱山（株）製）で、アルコールを溶媒として用い、２００ｒｐｍ、３０分粉砕を行った。その後ろ過し、ヘンシェルミキサー（三井鉱山（株）製）で攪拌しながら真空加熱乾燥を行い、Ｓｍ−Ｆｅ−Ｍｎ−Ｎ粉砕粉を製造し、実施例３とした。
実施例１〜３、比較例１、２のＳｍ−Ｆｅ−Ｍｎ−Ｎ粗粉、Ｓｍ−Ｆｅ−Ｍｎ−Ｎ粉砕粉の平均粒径を表１、Ｓｍ−Ｆｅ−Ｍｎ−Ｎ組成、磁気特性を表２に示す。
実施例１、２は、比較例１、２に比較し粉末特性が同等以上であり、実施例３は、さらに特性が高いことが分かる。このように実施例によれば、水素ガスを使用せずまたは使用量を削減して、安全かつ安価に高特性のＳｍ−Ｆｅ−Ｍｎ−Ｎ粗粉・粉砕粉を製造できる。 (Examples 1-3, Comparative Examples 1-3)
Sm—Fe—Mn—N alloy magnet powder was produced by the following production method. First, Fe powder (purity 99.0 atomic% or more), Mn 2 O 3 (purity 99.0 atomic% or more), and Sm 2 O 3 (99.0 atomic% or more) were prepared as starting materials. An excessive amount of Ca (purity: 99.3% or more) was added to the above raw materials so that Sm 2 O 3 and Mn 2 O 3 as reducing agents could be sufficiently reduced, and mixed for 1 hour in a mixer. The resulting mixture was put into a reaction vessel, holes were made at equal intervals so that water could easily penetrate, and then transferred to a reduction diffusion vessel, then charged into an electric furnace (reduction diffusion furnace) and purged with argon. Thereafter, the argon flow rate was 0.5 to 1 L / min, held at 1200 ° C. for 8 hours, Sm 2 O 3 and Mn 2 O 3 were reduced and diffused in Fe to produce a reduced product of Sm—Fe—Mn alloy. .
In Example 1, 10 kg of the reduced product is put in a stainless steel container that can be evacuated, vacuumed to 0.001 MPa, and then 230 cc / kg of pure water (230 g of pure water for 1 kg of the reduced product) is put directly on the reduced product. The reduced product was reacted with water and left for 12 hours.
In Example 2, 10 kg of the reduced product was put into a stainless steel container that could be evacuated, and after evacuating to 0.001 MPa, 52 cc / kg of pure water was added so as to directly apply the reduced product, and the reduced product was reacted with water for 4 hours. Then, hydrogen gas was flowed so that the internal pressure of the container became 0.11 to 0.14 MPa (hydrogen amount 8 L / kg), and hydrogen collapsed for 8 hours.
In Comparative Example 1, the reducing diffusion condition was 1300 ° C. for 12 hours, and no disintegration treatment with water or hydrogen gas was performed.
In Comparative Example 2, it was carried out under the same reducing diffusion conditions as in Example 1, without performing a disintegration treatment with water. Hydrogen gas was allowed to flow so that the hydrogen collapsed for 12 hours.
Thereafter, the reduced products of Examples 1 and 2 and Comparative Examples 1 and 2 were each placed in a water tank containing 10 L of water, stirred for 10 minutes, drained the supernatant, and this operation was repeated 10 times to remove Ca. The pickling treatment was performed using acetic acid. Then, it decanted with alcohol and dried in vacuum at 100 ° C. for 5 hours to obtain Sm—Fe—Mn mother alloy powder.
Next, the obtained mother alloy powder was subjected to nitriding treatment at 480 ° C. for 8 hours in an ammonia-hydrogen mixed gas, and then hydrogen annealing and nitrogen annealing were performed to produce Sm—Fe—Mn—N coarse powder.
Further, 1 kg of the magnet coarse powder (sample) obtained in Example 1 was pulverized with an attritor (manufactured by Mitsui Mining Co., Ltd.) using alcohol as a solvent at 200 rpm for 30 minutes. Thereafter, the mixture was filtered and vacuum-heated and dried while stirring with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) to produce Sm—Fe—Mn—N pulverized powder.
Table 1 shows the average particle diameters of the Sm-Fe-Mn-N coarse powders and Sm-Fe-Mn-N pulverized powders of Examples 1 to 3 and Comparative Examples 1 and 2. Table 1, Sm-Fe-Mn-N composition, magnetic properties Is shown in Table 2.
It can be seen that Examples 1 and 2 have the same or higher powder characteristics than Comparative Examples 1 and 2, and Example 3 has higher characteristics. As described above, according to the embodiment, high-quality Sm—Fe—Mn—N coarse powder and pulverized powder can be produced safely and inexpensively without using hydrogen gas or by reducing the amount used.

Figure 0005104391
Figure 0005104391

Figure 0005104391
Figure 0005104391

（実施例４〜６、比較例３、４）
上記実施例１〜３、比較例１、２で製造したＳｍ−Ｆｅ−Ｍｎ−Ｎ粗粉・粉砕粉をそれぞれ９１．０重量％採り、これに熱可塑性樹脂１２ナイロン（ＰＡ１２（宇部興産（株）製）を９．０重量％の割合で混合し、ボンド磁石用組成物を調製した。
次に、このボンド磁石用組成物をナカタニ混練機（ナカタニ製）で１９０℃−１パス、その後、シリンダー温度２１０℃、成形圧力１ｔｏｎでφ２０×１３ｍｍの形状に射出成形した。実施例４〜６、比較例３、４で組成物を射出成形した成形体を各々成形体１〜５とした。
得られた射出成形ボンド磁石の磁気特性を表３に示す。実施例４、５の成形体１，２は、比較例３、４の成形体４，５に比較すると磁気特性が同等以上であり、実施例６の成形体３は、さらに特性が高いことが分かる。 (Examples 4 to 6, Comparative Examples 3 and 4)
91.0% by weight of the Sm—Fe—Mn—N coarse powder and pulverized powder produced in each of Examples 1 to 3 and Comparative Examples 1 and 2, respectively, was used, and thermoplastic resin 12 nylon (PA12 (Ube Industries, Ltd. )) Was mixed at a ratio of 9.0% by weight to prepare a bonded magnet composition.
Next, this bonded magnet composition was injection-molded into a shape of φ20 × 13 mm with a Nakatani kneading machine (manufactured by Nakatani) at 190 ° C.-1 pass, and then at a cylinder temperature of 210 ° C. and a molding pressure of 1 ton. Molded bodies obtained by injection molding the compositions in Examples 4 to 6 and Comparative Examples 3 and 4 were molded bodies 1 to 5, respectively.
Table 3 shows the magnetic properties of the obtained injection-molded bonded magnet. The molded bodies 1 and 2 of Examples 4 and 5 have the same or higher magnetic properties than the molded bodies 4 and 5 of Comparative Examples 3 and 4, and the molded body 3 of Example 6 has higher characteristics. I understand.

Figure 0005104391
Figure 0005104391

Claims (9)

遷移金属合金粉末、希土類酸化物粉末、及び該希土類酸化物を還元するための還元剤を混合し、この混合物を非酸化性雰囲気中で加熱焼成して希土類−遷移金属系母合金を含む還元拡散反応生成物を得て、次いで、該反応生成物を水中に投入し崩壊させて、得られた平均粒径が５〜５０μｍである希土類−遷移金属合金粉末を窒化処理することにより、下記の一般式（１）で表される希土類−遷移金属−窒素系磁石粉末を得る製造方法において、
前記還元拡散反応生成物を水に投入して崩壊させる前に、密閉容器に入れ該還元拡散反応生成物の表面に水、または水と水素ガスを供給して、該反応生成物に含まれる過剰な還元剤、及び、希土類−遷移金属系合金粉末表面と反応させ、発生する水素またはこれと供給した水素ガスを希土類−遷移金属系母合金に吸収させ、水素を吸収しながら合金相が膨張し還元拡散反応生成物に歪を生じさせること、及び、該反応生成物中の希土類−遷移金属系母合金同士を溶着させている還元剤を酸化物にすることを特徴とする希土類−遷移金属−窒素系磁石粉末の製造方法。
ＲｘＦｅ（１００−ｘ−ｙ−ｚ）ＭｙＮｚ ・・・（１）
（式（１）中、Ｒは１種または２種以上の希土類元素、ＭはＣｕ、Ｍｎ、Ｃｏ、Ｃｒ、Ｔｉ、ＮｉおよびＺｒからなる群から選択される１種または２種以上の遷移金属元素を示し、また、ｘ、ｙ、ｚは原子％で、４≦ｘ≦１８、０．３≦ｙ≦２３、１５≦ｚ≦２５を満たす。） Reduction diffusion containing a rare earth-transition metal master alloy by mixing transition metal alloy powder, rare earth oxide powder, and a reducing agent for reducing the rare earth oxide, and heating and firing the mixture in a non-oxidizing atmosphere. A reaction product is obtained, and then the reaction product is thrown into water to disintegrate. The resulting rare earth-transition metal alloy powder having an average particle size of 5 to 50 μm is subjected to nitriding treatment as described below. In the production method for obtaining the rare earth-transition metal-nitrogen based magnet powder represented by the formula (1),
Prior to collapsing by introducing the reducing diffusion reaction product in water, the water on the surface of the placed in a sealed container The reduction diffusion reaction products or by supplying water and hydrogen gas, excess contained in the reaction product Reactive agent and rare earth-transition metal alloy powder surface reacts, and the generated hydrogen or the supplied hydrogen gas is absorbed by the rare earth-transition metal master alloy, and the alloy phase expands while absorbing hydrogen. Rare earth-transition metal, characterized in that a reduction diffusion reaction product is distorted, and a reducing agent in which the rare earth-transition metal master alloy in the reaction product is welded to an oxide. A method for producing nitrogen-based magnet powder.
R x Fe (100-x- y-z) M y N z ··· (1)
(In the formula (1), R is one or more rare earth elements, M is one or more transition metals selected from the group consisting of Cu, Mn, Co, Cr, Ti, Ni and Zr. Represents an element, and x, y, and z are atomic% and satisfy 4 ≦ x ≦ 18, 0.3 ≦ y ≦ 23, and 15 ≦ z ≦ 25.) 還元拡散反応生成物を崩壊させる際、密閉容器内への水の供給量が、該反応生成物１ｋｇあたり５〜５００ｍｌであることを特徴とする請求項１に記載の希土類−遷移金属−窒素系磁石粉末の製造方法。 2. The rare earth-transition metal-nitrogen system according to claim 1, wherein when the reduction-diffusion reaction product is disrupted, the amount of water supplied into the sealed container is 5 to 500 ml per 1 kg of the reaction product. Manufacturing method of magnet powder. 還元拡散反応生成物を崩壊させる際、密閉容器内への水素の供給量が、該反応生成物１ｋｇあたり４０Ｌ以下であることを特徴とする請求項１に記載の希土類−遷移金属−窒素系磁石粉末の製造方法。 2. The rare earth-transition metal-nitrogen magnet according to claim 1, wherein when the reduction-diffusion reaction product is collapsed, the supply amount of hydrogen into the sealed container is 40 L or less per 1 kg of the reaction product. Powder manufacturing method. 密閉容器内へ水のみを還元拡散反応生成物に供給する場合、供給後に７〜１５時間放置することを特徴とする請求項１又は２に記載の希土類−遷移金属−窒素系磁石粉末の製造方法。 3. The method for producing a rare earth-transition metal-nitrogen magnet powder according to claim 1, wherein when only water is supplied to the reduced diffusion reaction product into the sealed container, the product is left for 7 to 15 hours after the supply. . 密閉容器内へ水と水素ガスを還元拡散反応生成物に供給する場合、水素を供給した後、７〜１０時間放置することを特徴とする請求項１〜３のいずれかに記載の希土類−遷移金属−窒素系磁石粉末の製造方法。 The rare earth-transition according to any one of claims 1 to 3, wherein when water and hydrogen gas are supplied to the reduction diffusion reaction product into the sealed container , the hydrogen is supplied and then left for 7 to 10 hours. A method for producing metal-nitrogen magnet powder. 得られた希土類−遷移金属−窒素合金の粗粉末が、さらに微粉砕または解砕されることを特徴とする請求項１に記載の希土類−遷移金属−窒素系磁石粉末の製造方法。   The method for producing a rare earth-transition metal-nitrogen based magnet powder according to claim 1, wherein the obtained coarse powder of the rare earth-transition metal-nitrogen alloy is further finely pulverized or pulverized. 請求項１〜６のいずれかに記載の製造方法によって得られ、平均粒径が１〜３０μｍである希土類−遷移金属−窒素系磁石粉末。   A rare earth-transition metal-nitrogen based magnet powder obtained by the production method according to any one of claims 1 to 6 and having an average particle diameter of 1 to 30 µm. 請求項７に記載の希土類−遷移金属−窒素系磁石粉末に、熱可塑性樹脂または熱硬化性樹脂のいずれかを樹脂バインダーとして配合してなる希土類−遷移金属−窒素系ボンド磁石用組成物。   A composition for a rare earth-transition metal-nitrogen based bond magnet comprising the rare earth-transition metal-nitrogen based magnet powder according to claim 7 blended with either a thermoplastic resin or a thermosetting resin as a resin binder. 請求項８に記載のボンド磁石用組成物を圧縮成形又は射出成形してなる希土類−遷移金属−窒素系ボンド磁石。   A rare earth-transition metal-nitrogen based bonded magnet obtained by compression molding or injection molding the bonded magnet composition according to claim 8.
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