JPH08130142A - Manufacturing for rear-earth magnet - Google Patents

Abstract

PURPOSE: To provide raw slurry with good fluidity and impregnation, by adding a given quantity of olein acid to rear-earth permanent magnetic powder and/or mineral, composite or vegetable oil and/or these mixed materials. CONSTITUTION: After mineral, composite or vegetable oil is mixed with magnetic powder for RCo5 -, R2 Co17 - or R-Fe-B-based rear-earth permanent magnet (R is one or two kinds of rear-earth material including Y), a given quantity of olein acid of 0.01 to 0.5wt% to the total weight is added to these mixed materials. The mixed materials are put in a ball mill and stirred with a steel ball coated with plastics as a medium to obtain raw slurry 7. The raw slurry 7 is molded in a given continuous molding machine. In the molding step, a magnetic field is applied to a die cavity, to which the raw slurry 7 from a pressurized feeding unit 8 is charged under pressure. After a deoiling step, the raw slurry 7 is sintered at a given temperature under pressure.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、ＲＣｏ₅系、Ｒ₂Ｃｏ₁₇
系あるいはＲ−Ｆｅ−Ｂ系（ＲはＹを含む希土類元素の
内の１種類または２種類以上）希土類永久磁石の製造方
法に関するものである。The present invention relates to RCo ₅ system, R ₂ Co ₁₇
System or R-Fe-B system (R is one or more kinds of rare earth elements including Y) Rare earth permanent magnet manufacturing method.

【０００２】[0002]

【従来の技術】一般に希土類永久磁石は原料金属を溶解
しインゴットを作製し、そのインゴットを粗粉砕、微粉
砕、成形、焼結、熱処理、加工して製造される。この
際、微粉砕は不活性高圧ガス雰囲気中で粒子どうしを衝
突させ乾粉を得るジェットミル粉砕法、ボ−ルミル 、
振動ミル等を用い、有機溶剤中で原料粉を粉砕しその後
有機溶媒を乾燥させて、乾粉を得る湿式粉砕法で行われ
るのが一般的である。乾粉を成形するにあたっては、所
定量の乾粉を秤量し、これを金型キャビティ内に投入す
る方法が取られ、給粉後、配向磁場を印加して成形を行
う。また、あらかじめ磁場を印加したキャビティ内に上
記方法で乾粉を給粉し、成形する方法が採られる場合も
ある。一方、微粉砕後の希土類焼結磁石用粉末は、化学
的に非常に活性であるために大気中で急激に酸化し、磁
気特性の劣化を招いてしまう。これを防止する方法とし
ては、例えば特開昭５８−１５７９２号、特開昭６１−
１１４５０５号、特開平１−３０３７１０号、特開平３
−１５０４号、特開平４−８３３１９号に開示されてい
るように、原料粉末と有機溶媒との混合物を作製し、こ
れを上記の乾粉と同様の方法で金型キャビティ内に給粉
し、磁界中にて成形し、得られた成形体を乾燥、焼結及
び熱処理する製造方法がある。この製造方法によれば、
湿式で成形するものの乾粉で問題となる酸化による経時
変化は避けられず、また原料混合物の配向磁界に対する
配向性も不十分であるため、希土類永久磁石粉が有する
磁気的なポテンシャルを十分に引き出せず、得られる永
久磁石の水準は、満足すべきものではなかった。かかる
問題に対して、たとえば特願平５−２００５４３におい
ては希土類焼結磁石原料とある種の鉱物油、合成油或い
は植物油とを混合し原料混合物とする事により耐酸化性
を向上させ、この原料混合物を金型キャビティ−内に一
定の圧力以上で加圧注入し加圧充填し、これを湿式成形
することによって希土類磁石の配向を大幅に改善してい
る。2. Description of the Related Art Generally, a rare earth permanent magnet is manufactured by melting a raw material metal to produce an ingot, and coarsely pulverizing, finely pulverizing, molding, sintering, heat treating and processing the ingot. At this time, fine pulverization is performed by a jet mill pulverizing method in which particles are collided in an inert high pressure gas atmosphere to obtain a dry powder, a ball mill,
It is general to carry out a wet pulverization method in which a raw material powder is pulverized in an organic solvent using a vibration mill or the like and then the organic solvent is dried to obtain a dry powder. When molding the dry powder, a method of weighing a predetermined amount of the dry powder and charging the dry powder into the mold cavity is used. After the powder is supplied, the orientation magnetic field is applied to perform the molding. In some cases, a method may be adopted in which dry powder is fed into the cavity to which a magnetic field has been applied in advance by the above method, and the powder is molded. On the other hand, the finely ground rare earth sintered magnet powder is chemically very active and therefore is rapidly oxidized in the atmosphere, resulting in deterioration of magnetic properties. As a method for preventing this, for example, JP-A-58-15792 and JP-A-61-
114505, JP-A-1-303710, JP-A-3
No. 1504, JP-A-4-83319, a mixture of a raw material powder and an organic solvent is prepared, and this is powdered in a mold cavity in the same manner as the above dry powder, and a magnetic field is applied. There is a manufacturing method in which the molded body is molded in the inside and the obtained molded body is dried, sintered and heat treated. According to this manufacturing method,
Although it is wet-molded, the change over time due to oxidation, which is a problem with dry powder, is unavoidable, and the orientation of the raw material mixture with respect to the orientation magnetic field is insufficient, so the magnetic potential of the rare earth permanent magnet powder cannot be fully drawn out. The level of permanent magnets obtained was not satisfactory. In order to solve such a problem, for example, in Japanese Patent Application No. 5-200543, a rare earth sintered magnet raw material is mixed with a certain kind of mineral oil, synthetic oil or vegetable oil to form a raw material mixture to improve oxidation resistance. The orientation of the rare earth magnet is greatly improved by injecting the mixture into the mold cavity under a certain pressure or more, pressurizing and filling the mixture, and wet-molding the mixture.

【０００３】[0003]

【発明が解決しようとする課題】しかしながら、希土類
焼結磁石用の微粉末はその平均粒径が２〜６μｍ程度と
大きく、また凝集力も強いため、溶媒である鉱物油、合
成油或いは植物油中で沈降し、凝集体を作りやすく溶媒
とのなじみが不十分であった。その結果、原料混合物を
金型キャビティ−内に加圧注入する際に希土類磁石原料
と溶媒が分離しやすく粘性の非常に高い粘土状の原料混
合物が注入口に詰まる等の問題があった。また、原料混
合物はそれ自体の粘度が高く十分な流動性が得られてい
なかった。この発明は、上記の問題を解決するためのも
のであり、希土類焼結磁石原料の微粉末と溶媒である鉱
物油、合成油或いは植物油とのぬれ、分散性を改善し注
入性および流動性に優れた原料混合物スラリ−を提供す
ることを目的としている。However, the fine powder for rare earth sintered magnets has a large average particle size of about 2 to 6 μm and has a strong cohesive force, so that it can be used in a solvent such as mineral oil, synthetic oil or vegetable oil. It was easy to settle and form agglomerates, and the compatibility with the solvent was insufficient. As a result, when the raw material mixture is injected under pressure into the mold cavity, there is a problem that the rare earth magnet raw material and the solvent are easily separated and the clay-like raw material mixture having a very high viscosity is clogged in the injection port. In addition, the raw material mixture itself has a high viscosity and is not sufficiently fluid. This invention is to solve the above problems, wetting of fine powder of rare earth sintered magnet raw material and solvent mineral oil, synthetic oil or vegetable oil, improving the dispersibility to improve the injectability and fluidity. The purpose is to provide an excellent raw material mixture slurry.

【０００４】[0004]

【課題を解決するための手段】本発明者らは、上記問題
を解決するために原料混合物スラリ−について検討を重
ねた結果、親油性の界面活性剤を希土類永久磁石用の微
粉または／および、鉱物油、合成油或いは植物油または
／および、それらの混合物に添加することによりぬれ、
分散性を改善することに思い至った。また、この界面活
性剤について鋭意検討を進めた結果、オレイン酸を希土
類永久磁石用の微粉または／および、鉱物油、合成油或
いは植物油または／および、それらの混合物に添加する
ことによって希土類焼結磁石原料の微粉末と鉱物油、合
成油或いは植物油とのぬれ、分散性を効果的に改善でき
成形時の金型キャビティ−内への注入がスム−ズに行
え、流動性にも優れた原料混合物スラリ−を作るができ
ることを見いだし本発明に至った。以下本発明について
詳述する。希土類永久磁石用の微粉を鉱物油、合成油或
いは植物油に分散させる界面活性剤としてはカルボン
酸、、、アミン、スルホン酸、リン酸等やその塩および
エステルが挙げられる。その中でも特に、オレイン酸、
マレイン酸、フマル酸等の不飽和カルボン酸は二重結合
をもつことから特に有効と考えられるが小量で有効に作
用すること、溶媒への溶解度がたかいこと、脱溶媒過程
で除去できることによりオレイン酸が最も適当である。
添加量は０．０１ｗｔ％〜０．５ｗｔ％が適切である。
０．０１ｗｔ％未満では希土類永久磁石用の微粉の表面
エネルギ−を下げるのに十分ではなく、流動性、キャビ
ティ−への注入性に優れた原料混合物スラリ−とはなら
ない。また０．５ｗｔ％より多い場合は、焼結後の磁石
において炭素が多量に残存し磁気特性を著しく低下させ
る。また添加方法については限定されない。すなわち、
溶媒へオレイン酸を溶解した後希土類永久磁石用の微粉
を投入し、混合、攪拌してもよいし、希土類永久磁石用
の微粉にオレイン酸を混合した後に溶媒を加え、攪拌し
てもよい。あるいは、溶媒と希土類永久磁石用の微粉を
混合した後にオレイン酸を混合、攪拌してもよいし、こ
れらの方法のうち２つ以上を使ってもよい。この際、攪
拌は手動でもよいがボ−ルミル、ロ−ルミル、ディスパ
−サ−等の攪拌機を用いてもよい。希土類原料微粉末
は、あらかじめ所定量用意してもよいが、ジェットミル
等の粉砕機に微粉排出口に鉱物油、合成油、植物油ある
い、これらとオレイン酸の混合物を設置し、排出される
微粉を直接回収する方法を採ることもできる。また、ボ
−ルミル等で鉱物油、合成油或いは植物油を溶媒として
粉砕を行う際に、粉砕の前や途中にオレイン酸を加えて
粉砕を行ってもよい。本発明の溶媒として使用する鉱物
油、合成油はその種類が特定されるものではないが、常
温での動粘度が１０ｃＳｔを越えると粘性の増大によっ
て微粉相互の結合力が強まって磁場中湿式成形時の微粉
の配向性に悪影響を与える。このため鉱物油、合成油の
常温での動粘度は１０ｃＳｔ以下である事が望ましい。
また鉱物油、合成油の分留点が４００℃を越えると焼結
時の脱溶媒が困難となり、焼結体内の残留炭素量が多く
なって磁気特性の低下をもたらす。従って鉱物油、合成
油の分留点は４００℃以下でならなくてはならない。植
物油は植物より抽出される油を指し、その種類も特定の
植物に限定されるものではない。例えば、大豆油、なた
ね油、コ−ン油、べにばな油、ひまわり油などがあげら
れる。以上において、原料混合物中の希土類永久磁石用
微粉の量比は重量百分率で５０〜８５％が望ましい。微
粉の量比が５０％未満の場合、原料混合物中の溶媒の割
合が多くなって上澄みが生じ、原料混合物の定量供給が
困難となる。また、微粉の量比が８５％より多い場合、
溶媒の割合が少なすぎて原料混合物の定量供給に困難を
生じる。 以上のように作製した原料混合物の湿式成形
の方法は特に限定されない。例えば、原料混合物を金型
キャビティ−に擦り切りによって充填し、配向磁場を印
加して磁場中で加圧成形する。または原料混合物を金型
キャビティ−に定量秤量して直接投入し、配向磁場を印
加して磁場中で加圧成形しても良い。さらには、金型キ
ャビティ−に配向磁場を印加して、次いで金型にあけた
注入口より原料混合物を加圧注入し、その後磁場中で加
圧成形することもできる。これらいずれかの成形方法に
おいてもたとえば、上パンチや下パンチ面に溶媒は排出
用の穴を設け、加圧成型時の微粉の流出を防ぐために布
製、紙製等のフィルタを用いたり、あるいは上パンチや
下パンチの一部を多孔質フィルタ材料とするなどの工夫
が必要である。成形後の成形体には溶媒が残存している
ため、そのまま通常の焼結を行なうと、残存していた溶
媒が加熱時に蒸発して焼結炉内を汚染するとともに、一
部は分解して焼結体中に残存する。このために焼結体の
残存炭素量が増加して焼結体密度が低下し、最大エネル
ギ−積が低下する。このため成形体は脱溶媒処理を行っ
て焼結する必要がある。脱溶媒処理は０．１Ｔｏｒｒ以
下の減圧下で成形体を１００から５００℃の温度範囲に
３０分以上保持することによって行なう。尚、保持は１
００から５００℃の範囲であれば一点である必要はな
く、二点以上であっても良い。また０．１Ｔｏｒｒ以下
の減圧下で室温から５００℃までの昇温速度を１０℃／
ｍｉｎ以下とすることによっても脱溶媒を行うことがで
きる。脱溶媒処理後の成形体は、引き続いて焼結温度ま
で加熱しその温度で一定時間保持することによって焼結
体とする。Means for Solving the Problems As a result of repeated studies on a raw material mixture slurry in order to solve the above problems, the present inventors have found that a lipophilic surfactant is used as a fine powder for rare earth permanent magnets and / or Wetting by adding to mineral oils, synthetic oils or vegetable oils and / or mixtures thereof,
I came up with the idea of improving dispersibility. Further, as a result of earnestly studying this surfactant, as a result of adding oleic acid to fine powder for rare earth permanent magnets and / or mineral oil, synthetic oil or vegetable oil or / and a mixture thereof, a rare earth sintered magnet is added. Mixture of fine powder of raw material with mineral oil, synthetic oil or vegetable oil, which can effectively improve dispersibility, can be smoothly injected into the mold cavity at the time of molding, and has excellent fluidity The inventors have found that a slurry can be made and have reached the present invention. The present invention will be described in detail below. Surfactants for dispersing fine powders for rare earth permanent magnets in mineral oil, synthetic oil or vegetable oil include carboxylic acid, amine, sulfonic acid, phosphoric acid, etc. and salts and esters thereof. Among them, especially oleic acid,
Unsaturated carboxylic acids such as maleic acid and fumaric acid are considered to be particularly effective because they have a double bond, but they are effective in a small amount, have high solubility in a solvent, and can be removed in the desolvation process to remove olein. Acid is most suitable.
The appropriate addition amount is 0.01 wt% to 0.5 wt%.
If it is less than 0.01 wt%, it is not sufficient to lower the surface energy of the fine powder for rare earth permanent magnets, and the raw material mixture slurry is not excellent in fluidity and injectability into the cavity. On the other hand, if it is more than 0.5 wt%, a large amount of carbon remains in the magnet after sintering and the magnetic characteristics are remarkably deteriorated. The addition method is not limited. That is,
After dissolving oleic acid in a solvent, fine powder for rare earth permanent magnet may be added and mixed and stirred, or solvent may be added and stirred after mixing oleic acid with fine powder for rare earth permanent magnet. Alternatively, the solvent and the fine powder for the rare earth permanent magnet may be mixed and then oleic acid may be mixed and stirred, or two or more of these methods may be used. At this time, stirring may be performed manually, but a stirrer such as a ball mill, a roll mill or a disperser may be used. The rare earth raw material fine powder may be prepared in a predetermined amount in advance, but it is discharged by installing a mineral oil, a synthetic oil, a vegetable oil or a mixture of these and oleic acid at the fine powder discharge port in a pulverizer such as a jet mill. A method of directly collecting the fine powder can also be adopted. Further, when pulverizing with a ball mill or the like using a mineral oil, a synthetic oil or a vegetable oil as a solvent, oleic acid may be added before or during the pulverization for pulverization. The types of the mineral oil and the synthetic oil used as the solvent of the present invention are not specified, but when the kinematic viscosity at room temperature exceeds 10 cSt, the cohesive force between the fine powders is strengthened due to the increase in viscosity, and wet molding in a magnetic field is performed. This adversely affects the orientation of fine powder. Therefore, it is desirable that the kinematic viscosity of the mineral oil and the synthetic oil at room temperature be 10 cSt or less.
If the fractional distillation point of mineral oil or synthetic oil exceeds 400 ° C, it becomes difficult to remove the solvent during sintering, and the amount of residual carbon in the sintered body increases, resulting in deterioration of magnetic properties. Therefore, the fractional distillation points of mineral oils and synthetic oils must be below 400 ° C. Vegetable oil refers to an oil extracted from a plant, and its type is not limited to a particular plant. Examples thereof include soybean oil, rapeseed oil, corn oil, safflower oil, sunflower oil and the like. In the above, the amount ratio of the fine powder for rare earth permanent magnet in the raw material mixture is preferably 50 to 85% in weight percentage. When the amount ratio of the fine powder is less than 50%, the ratio of the solvent in the raw material mixture is increased and a supernatant is generated, which makes it difficult to quantitatively supply the raw material mixture. Also, when the amount ratio of fine powder is more than 85%,
The proportion of the solvent is too small, which makes it difficult to quantitatively supply the raw material mixture. The method of wet-molding the raw material mixture produced as described above is not particularly limited. For example, the raw material mixture is filled in a mold cavity by scraping, an orientation magnetic field is applied, and pressure molding is performed in the magnetic field. Alternatively, the raw material mixture may be quantitatively weighed and directly put into the mold cavity, and an orientation magnetic field may be applied to perform pressure molding in the magnetic field. Further, it is also possible to apply an orientation magnetic field to the mold cavity, then inject the raw material mixture under pressure from an injection port opened in the mold, and thereafter perform pressure molding in the magnetic field. In any of these molding methods, for example, a hole for discharging the solvent is provided on the upper punch or the lower punch surface, and a filter made of cloth, paper, or the like is used to prevent the outflow of fine powder during pressure molding, or the upper punch is used. It is necessary to take some measures such as using part of the punch or lower punch as a porous filter material. Since the solvent remains in the molded body after molding, if normal sintering is performed as it is, the remaining solvent evaporates during heating and contaminates the sintering furnace, and part of it decomposes. It remains in the sintered body. For this reason, the amount of residual carbon in the sintered body increases, the density of the sintered body decreases, and the maximum energy product decreases. Therefore, it is necessary to remove the solvent from the molded body and sinter it. The desolvation treatment is performed by maintaining the molded body in the temperature range of 100 to 500 ° C. for 30 minutes or more under a reduced pressure of 0.1 Torr or less. In addition, hold 1
The temperature does not have to be one and may be two or more as long as it is in the range of 00 to 500 ° C. In addition, the temperature rising rate from room temperature to 500 ° C under a reduced pressure of 0.1 Torr or less is 10 ° C /
Desolvation can also be performed by adjusting the amount to be min or less. The molded body after the desolvation treatment is subsequently heated to the sintering temperature and held at that temperature for a certain period of time to obtain a sintered body.

【０００５】[0005]

【実施例】以下、本発明を実施例を持って具体的に説明
するが、本発明の内容はこれによって限定されるもので
はない。EXAMPLES The present invention will be specifically described below with reference to examples, but the contents of the present invention are not limited thereto.

【０００６】（実施例１）Ｎｄ２８．０ｗｔ％、Ｄｙ
１．０ｗｔ％、Ｐｒ０．５ｗｔ％、Ｇａ０．１ｗｔ％、
Ｂ１．１ｗｔ％ 、残部Ｆｅの組成を有するＮｄ−Ｆｅ
−Ｂ系希土類磁石粗粉を酸素濃度３ｐｐｍのＡｒ気流中
にてジェットミル粉砕し、粉砕器の微粉排出口に鉱物油
（出光興産製、商品名ＭＣ．ＯＩＬ．Ｐ−０２）とオレ
イン酸を所定量の比で混合した液体を満たした容器を設
置し、粉砕後直接回収した。この混合物をボ−ルミルに
入れ、プラスチックでコ−トされた剛球を媒体にして３
時間攪拌し、これを原料スラリ−とした。得られた希土
類磁石微粉の平均粒径は４．２μｍであった。また原料
スラリ−中の希土類磁石微粉は７０ｗｔ％，オレイン酸
の量はそれぞれ０．０２、０．１、０．５ｗｔ％であっ
た。これらの原料スラリ−の動粘度をＢ型粘度計にて測
定した後、図１に示すような成形装置にて連続成形をお
こなった。成形条件は金型キャビティ−に１０ｋＯｅの
磁場を印加し、ここへ加圧供給装置に充填した原料スラ
リ−を１０kgf/cm²の注入圧力で注入、充填した。原料
スラリ−を金型キャビティ−内に充填した後、配向磁場
を印加したまま成形圧力２．０ｔｏｎ／cm²で湿式成形
し成形体を得た。なおこの場合フィルタは１ｍｍ厚さの
布製のものを使用した。つぎに成形体に５×１０^-2Ｔor
rの圧力下で、室温から５００度までの昇温速度が５℃
／ｍｉｎの脱油処理を施し、その後同じ圧力で１０７０
℃までを３０℃／ｍｉｎの昇温速度で昇温し、その温度
で４時間保持して焼結した。焼結体はＡｒガス雰囲気中
で９００℃×２時間と、６００℃×１時間の熱処理を各
一回施した後磁気特性および、炭素量を測定した。その
結果表１に示すように原料スラリ−の動粘度、連続成形
性、焼結体の磁気特性共に良好な値を得た。(Example 1) Nd 28.0 wt%, Dy
1.0 wt%, Pr0.5 wt%, Ga0.1 wt%,
B1.1 wt%, Nd-Fe having the composition of balance Fe
-B-based rare earth magnet coarse powder is jet-milled in an Ar stream having an oxygen concentration of 3 ppm, and mineral oil (manufactured by Idemitsu Kosan Co., Ltd., product name MC.OIL.P-02) and oleic acid are pulverized in a fine powder outlet of the pulverizer. A container filled with a liquid mixed in a predetermined amount ratio was set, crushed, and directly collected. This mixture was placed in a ball mill, and hard spheres coated with plastic were used as media.
After stirring for a time, this was used as a raw material slurry. The average particle diameter of the obtained rare earth magnet fine powder was 4.2 μm. The rare earth magnet fine powder in the raw material slurry was 70 wt%, and the amounts of oleic acid were 0.02, 0.1 and 0.5 wt%, respectively. After measuring the kinematic viscosity of these raw material slurries with a B type viscometer, continuous molding was performed with a molding apparatus as shown in FIG. The molding conditions were such that a magnetic field of 10 kOe was applied to the mold cavity, and the raw material slurry filled in the pressure supply device was injected and filled therein at an injection pressure of 10 kgf / cm ² . After filling the raw material slurry into the mold cavity, it was wet-molded at a molding pressure of 2.0 ton / cm ² while applying an orientation magnetic field to obtain a molded body. In this case, the filter used was a cloth having a thickness of 1 mm. Next, 5 × 10 ^-2 Tor is applied to the molded body.
Under the pressure of r, the heating rate from room temperature to 500 degrees is 5 ° C.
/ Min degreasing treatment, then 1070 at the same pressure
The temperature was raised to 30 ° C. at a heating rate of 30 ° C./min, and the temperature was maintained for 4 hours for sintering. The sintered body was subjected to a heat treatment of 900 ° C. × 2 hours and 600 ° C. × 1 hour once in an Ar gas atmosphere, and the magnetic characteristics and the amount of carbon were measured. As a result, as shown in Table 1, good values were obtained for the kinematic viscosity of the raw material slurry, the continuous formability, and the magnetic properties of the sintered body.

【０００７】（比較例１）実施例１で使用したのと同一
のＮｄ−Ｆｅ−Ｂ系希土類磁石原料粗粉を実施例１と同
様の方法で粉砕し、鉱物油（出光興産製、商品名ＭＣ．
ＯＩＬ．Ｐ−０２）とオレイン酸の混合物中に回収した
後ボ−ルミルにて攪拌した。ただし原料スラリ−中のオ
レイン酸量は０、０．００５、１．０wt％であった。こ
の原料スラリ−の動粘度を測定したあと実施例１と同様
の条件にて成形、脱油、焼結、熱処理を行い、磁気特性
を評価した。その結果、表１に示すようにオレイン酸添
加量が０．０１ｗｔ％未満の場合は粘度が高く、溶媒で
ある鉱物油がぬけやすいため数回の成形で成形機の注入
口付近に鉱物油がぬけた粘度の非常に大きな原料スラリ
−がつまり連続成形もできない。また、０．５ｗｔ％よ
り多くなると焼結体中の炭素量が多くなり磁気特性が低
い値しか得らない事がわかる。(Comparative Example 1) The same Nd-Fe-B rare earth magnet raw powder as used in Example 1 was pulverized in the same manner as in Example 1 to obtain a mineral oil (trade name, manufactured by Idemitsu Kosan Co., Ltd.). MC.
OIL. P-02) and oleic acid were recovered in a mixture and then stirred with a ball mill. However, the amounts of oleic acid in the raw material slurry were 0, 0.005 and 1.0 wt%. After measuring the kinematic viscosity of this raw material slurry, molding, deoiling, sintering and heat treatment were performed under the same conditions as in Example 1 to evaluate the magnetic properties. As a result, as shown in Table 1, when the added amount of oleic acid is less than 0.01 wt%, the viscosity is high and the mineral oil that is the solvent is easy to drain, so that the mineral oil will be near the injection port of the molding machine in several moldings. A raw material slurry having a very high viscosity is blocked, and continuous molding cannot be performed. Further, it can be seen that when the content is more than 0.5 wt%, the amount of carbon in the sintered body is large and the magnetic properties are low.

【０００８】（実施例２）重量百分率でＳｍ２６．０
％、Ｆｅ１４．０％、Ｃｕ４．８％、Ｚｒ２．４％、Ｃ
ｏ５２．８％の組成を有するＳｍ₂Ｃｏ₁₇系希土類磁石
原料粗粉を鉱物油（出光興産製、商品名ＭＣ．ＯＩＬ．
Ｐ−０２）を溶媒として、ボ−ルミルで８時間湿式粉砕
をした。このときオレイン酸も同時に添加した。粉砕後
に得られた原料スラリ−は希土類磁石原料微粉６５ｗｔ
％、オレイン酸の量はそれぞれ０．０２、０．５ｗｔ％
であった。また、希土類磁石原料微粉の平均粒径は４．
５μｍであった。これらの原料スラリ−の動粘度をＢ型
粘度計で測定した後図１に示すような成形装置にて連続
成形した。成形条件は、金型キャビティに８ｋＯｅの配
向磁場を印加し、ここへ加圧供給装置に充填した原料ス
ラリ−を１５ｋｇｆ／ｃｍ²の注入圧力で注入、充填し
た。原料スラリ−を金型キャビティ−内に充填した後、
配向磁場を印加したまま成形圧力４．０ｔｏｎ／ｃｍ²
で湿式成形し、成形体を得た。なお、この場合フィルタ
は０．５ｍｍの厚さの紙製のものを使用した。次に成形
体に５×１０^-2Ｔｏｒｒの圧力下で、室温から５００℃
までの昇温速度が５℃／ｍｉｎの脱油処理を施し、その
後同じ圧力で１２００℃までを２０℃／ｍｉｎの昇温速
度で昇温し、その温度で３時間保持して焼結した。焼結
体はＡｒガス雰囲気中で１１７０℃×４時間の溶体化処
理と７６０℃×１２時間の時効処理を各一回施した後磁
気特性および炭素量を測定した。その結果表２に示すよ
うに原料スラリ−の動粘度、連続成形性、焼結体の磁気
特性共に良好な値を得た。(Example 2) Sm 26.0 by weight percentage
%, Fe 14.0%, Cu 4.8%, Zr 2.4%, C
Sm ₂ Co ₁₇ rare earth magnet raw powder having a composition of 52.8% was converted into mineral oil (made by Idemitsu Kosan Co., Ltd. under the trade name MC.OIL.
Using P-02) as a solvent, wet milling was carried out for 8 hours with a ball mill. At this time, oleic acid was also added at the same time. The raw material slurry obtained after pulverization is 65 wt.
%, The amount of oleic acid is 0.02, 0.5 wt% respectively
Met. The average particle size of the rare earth magnet raw material fine powder is 4.
It was 5 μm. The kinematic viscosities of these raw material slurries were measured with a B-type viscometer, and then continuously molded with a molding device as shown in FIG. As for the molding conditions, an orientation magnetic field of 8 kOe was applied to the mold cavity, and the raw material slurry filled in the pressure supply device was injected and filled into the mold cavity at an injection pressure of 15 kgf / cm ² . After filling the raw material slurry into the mold cavity,
Molding pressure 4.0 ton / cm ² with the orientation magnetic field applied
Was wet-molded to obtain a molded body. In this case, a filter made of paper having a thickness of 0.5 mm was used. Next, the molded body is heated from room temperature to 500 ° C. under a pressure of 5 × 10 ^-2 Torr.
Was subjected to a deoiling treatment at a temperature rising rate of 5 ° C./min, then heated to 1200 ° C. at a temperature rising rate of 20 ° C./min at the same pressure, and held at that temperature for 3 hours for sintering. The sintered body was subjected to a solution treatment at 1170 ° C. for 4 hours and an aging treatment at 760 ° C. for 12 hours once in an Ar gas atmosphere, and then the magnetic properties and the amount of carbon were measured. As a result, as shown in Table 2, good values were obtained for the kinematic viscosity of the raw material slurry, the continuous formability, and the magnetic properties of the sintered body.

【０００９】（比較例２）実施例２で使用したのと同一
のＳｍ₂Ｃｏ₁₇系希土類磁石原料粗粉をボ−ルミルにて
オレイン酸を加え、鉱物油（出光興産製、商品名ＭＣ．
ＯＩＬ．Ｐ−０２）を溶媒として湿式粉砕をし、原料ス
ラリ−とした。ただし原料スラリ−中に含まれるオレイ
ン酸の量はそれぞれ０、０．００３、１．０ｗｔ％であ
った。原料スラリ−中の希土類磁石原料微粉は６５ｗｔ
％その平均粒径は４．５μｍであり実施例２と同じであ
った。この原料スラリ−の粘度を測定した後、実施例２
と同じ条件で連続成形、脱油、焼結、熱処理を行い、磁
気特性を評価した。その結果、表２に示すようにオレイ
ン酸の添加量が０．０１ｗｔ％未満の場合は粘度が高い
うえ溶媒である鉱物油がぬけやすいため数回の成形で成
形機の注入口付近に鉱物油がぬけた粘度の非常に大きな
原料スラリ−がつまり連続成形もできなかった。 ま
た、０．５ｗｔ％より多くなるとになると焼結体中の炭
素量が多くなり磁気特性が低い値しか得られないことが
判る。(Comparative Example 2) Oreic acid was added to a crude powder of the same Sm ₂ Co ₁₇ type rare earth magnet raw material used in Example 2 by means of a ball mill, and a mineral oil (manufactured by Idemitsu Kosan, trade name MC.
OIL. P-02) was used as a solvent for wet pulverization to obtain a raw material slurry. However, the amounts of oleic acid contained in the raw material slurry were 0, 0.003 and 1.0 wt%, respectively. The rare earth magnet raw material fine powder in the raw material slurry is 65 wt.
% The average particle diameter was 4.5 μm, which was the same as in Example 2. After measuring the viscosity of this raw material slurry, Example 2
Under the same conditions as above, continuous molding, deoiling, sintering and heat treatment were performed to evaluate the magnetic properties. As a result, as shown in Table 2, when the added amount of oleic acid is less than 0.01 wt%, the viscosity is high and the mineral oil that is the solvent is easy to drain, so the mineral oil near the injection port of the molding machine can be molded several times. The raw material slurry having a very large viscosity was clogged, and continuous molding could not be performed. Further, it can be seen that when the content is more than 0.5 wt%, the amount of carbon in the sintered body is large and only a low magnetic property value can be obtained.

【００１０】[0010]

【発明の効果】以上詳述したように、希土類永久磁石用
の微粉と鉱物油、合成油或いは植物油を混合し、この混
合物を磁界中にて湿式加圧成形して成形体として、その
後脱脂、焼結する希土類永久磁石の製法において希土類
永久磁石用の微粉または／および、鉱物油、合成油或い
は植物油または／および、それらのの混合物にオレイン
酸を添加することによって、希土類永久磁石の微粉と鉱
物油、合成油或いは植物油とのなじみを改善し、原料混
合物スラリ−の粘度を下げるため湿式加圧成形が容易と
なり高性能な希土類磁石を量産することができるような
った。As described in detail above, fine powder for rare earth permanent magnets is mixed with mineral oil, synthetic oil or vegetable oil, and the mixture is wet pressure molded in a magnetic field to obtain a molded body, which is then degreased, Fine powders and minerals for rare earth permanent magnets by adding oleic acid to fine powders for rare earth permanent magnets and / or mineral oils, synthetic oils or vegetable oils, and / or mixtures thereof in a method for producing rare earth permanent magnets for sintering. It has become possible to mass-produce high-performance rare earth magnets by improving wettability with oils, synthetic oils or vegetable oils and reducing the viscosity of the raw material mixture slurry, which facilitates wet pressure molding.

【００１１】[0011]

【表１】 [Table 1]

【表２】 [Table 2]

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

【図１】本発明の実施例に用いた成形装置例FIG. 1 is an example of a molding apparatus used in an embodiment of the present invention.

【符号の説明】[Explanation of symbols]

１ 上パンチ、２ 下パンチ 、３ ダイ、４ 配向磁
場コイル、５ フィルタ、６ 溶媒排出口 ７ 原料混合物スラリ−、８ 加圧供給装置 、９ ヨ
−ク1 Upper punch, 2 Lower punch, 3 Die, 4 Orientation magnetic field coil, 5 Filter, 6 Solvent discharge port 7 Raw material mixture slurry, 8 Pressurizing supply device, 9 York

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 ＲＣｏ₅系、Ｒ₂Ｃｏ₁₇系あるいはＲ−Ｆ
ｅ−Ｂ系（ＲはＹを含む希土類元素の内の１種類または
２種類以上）希土類永久磁石用の微粉と鉱物油、合成油
或いは植物油を混合し、この混合物を磁界中にて湿式加
圧成形して成形体として、その後脱脂、焼結する希土類
永久磁石の製法において、希土類永久磁石用の微粉また
は／および、鉱物油、合成油或いは植物油または／およ
び、それらの混合物にオレイン酸を添加し、その添加量
が希土類永久磁石用の微粉と鉱物油、合成油或いは植物
油との混合物全体の０．０１ｗｔ％〜０．５ｗｔ％であ
ることを特徴とした希土類永久磁石の製造方法。1. RCo ₅ system, R ₂ Co ₁₇ system or R-F
e-B system (R is one or more of rare earth elements including Y) Fine powder for rare earth permanent magnet and mineral oil, synthetic oil or vegetable oil are mixed, and the mixture is wet-pressed in a magnetic field. In a method for producing a rare earth permanent magnet, which is formed into a compact, and then degreased and sintered, oleic acid is added to fine powder for rare earth permanent magnet or / and mineral oil, synthetic oil or vegetable oil or / and a mixture thereof. A method for producing a rare earth permanent magnet, characterized in that the added amount is 0.01 wt% to 0.5 wt% of the entire mixture of fine powder for rare earth permanent magnet and mineral oil, synthetic oil or vegetable oil.