JPH0684623A - Production of rare earth permanent magnet - Google Patents
Production of rare earth permanent magnetInfo
- Publication number
- JPH0684623A JPH0684623A JP4238334A JP23833492A JPH0684623A JP H0684623 A JPH0684623 A JP H0684623A JP 4238334 A JP4238334 A JP 4238334A JP 23833492 A JP23833492 A JP 23833492A JP H0684623 A JPH0684623 A JP H0684623A
- Authority
- JP
- Japan
- Prior art keywords
- powder
- rare earth
- alloy powder
- permanent magnet
- earth permanent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
- H01F1/047—Alloys characterised by their composition
- H01F1/053—Alloys characterised by their composition containing rare earth metals
- H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
- H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
- H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
Landscapes
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Hard Magnetic Materials (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、Ｒ2Ｆｅ14Ｂ金属間化
合物を主相とする希土類永久磁石を粉末冶金法より製造
する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rare earth permanent magnet having an R 2 Fe 14 B intermetallic compound as a main phase by a powder metallurgy method.
【０００２】[0002]
【従来の技術】Ｒ−Ｆｅ−Ｂ系磁石は、それまでのＳｍ
Ｃｏ系磁石を凌駕する最大エネルギ−積（（ＢＨ）ma
x）を得ることができる磁石として知られている（例え
ば特開昭５９−４６００８号公報）。このＲ−Ｆｅ−Ｂ
系磁石を粉末冶金法により製造する場合、従来は最終焼
結体組成とほぼ同一の組成を有する合金粉末を得て、こ
れを成形、焼結していた。しかし、この方法では焼結性
を促進するために比較的高い温度で焼結することが必要
となる。したがって、結晶成長が生じ、残留磁束密度Ｂ
ｒは増大するが保磁力ｉＨｃおよび減磁特性の角型性が
低下するという問題があった。これとは逆に焼結温度を
低下させた場合には、保磁力ｉＨｃおよび減磁特性の角
型性は向上するが残留磁束密度Ｂｒが低下してしまうと
いう問題があった。2. Description of the Related Art R-Fe-B magnets have been
Maximum energy product ((BH) ma that surpasses Co magnets
x) is known as a magnet (for example, JP-A-59-46008). This R-Fe-B
When a system magnet is manufactured by a powder metallurgy method, conventionally, an alloy powder having almost the same composition as the final sintered body composition was obtained, and this was molded and sintered. However, this method requires sintering at a relatively high temperature to promote sinterability. Therefore, crystal growth occurs and the residual magnetic flux density B
Although r is increased, there is a problem that the coercive force iHc and the squareness of the demagnetization characteristic are deteriorated. On the contrary, when the sintering temperature is lowered, the coercive force iHc and the squareness of the demagnetization characteristic are improved, but the residual magnetic flux density Br is lowered.
【０００３】以上の問題点を解決する方法として、特公
平１−１９４６１号に最終組成よりもＲの含有率が高く
融点の低い第１のＲ−Ｆｅ−Ｂ系合金粉末に、この合金
粉末よりもＲの含有率が低い第２のＲ−Ｆｅ−Ｂ系合金
粉末を混合、成形した後に焼結する方法（以下「ブレン
ド法」）が提案されている。このブレンド法によると、
低融点の第１のＲ−Ｆｅ−Ｂ系合金粉末を混合すること
により、焼結温度を低下させ、残留磁束密度Ｂｒを低下
させずに保磁力ｉＨｃを向上させることができるとされ
ている。As a method of solving the above problems, Japanese Patent Publication No. 1-19461 discloses a first R-Fe-B alloy powder having a higher R content and a lower melting point than the final composition. Also proposed is a method of mixing a second R—Fe—B based alloy powder having a low R content, molding the mixture, and sintering the mixture (hereinafter, “blending method”). According to this blending method,
It is said that by mixing the first R—Fe—B based alloy powder having a low melting point, the sintering temperature can be lowered and the coercive force iHc can be improved without lowering the residual magnetic flux density Br.
【０００４】[0004]
【発明が解決しようとする課題】特公平１−１９４６１
号の製造方法は以上のように優れた効果を有するもの
の、以下のような問題点が提起される。すなわち、Ｒ−
Ｆｅ−Ｂ系合金粉末は容易に酸化される希土類元素およ
びＦｅを含むが、とくにＲの含有率が高い前記第１のＲ
−Ｆｅ−Ｂ系合金粉末の酸化が製造工程中において容易
に進行し、その結果磁石の磁気特性を十分に引き出すこ
とができなかったのである。そこで本発明は、ブレンド
法において合金粉末の酸化を極力防止して磁気特性を十
分に引き出すことのできる製造方法の提供を課題とす
る。[Problems to be Solved by the Invention] Japanese Patent Publication No. 1-19461
Although the production method of No. 1 has the excellent effects as described above, the following problems are raised. That is, R-
The Fe-B alloy powder contains a rare earth element and Fe that are easily oxidized, and the first R having a particularly high R content.
The oxidation of the —Fe—B alloy powder easily progressed during the manufacturing process, and as a result, the magnetic characteristics of the magnet could not be sufficiently obtained. Therefore, an object of the present invention is to provide a manufacturing method capable of preventing the alloy powder from being oxidized as much as possible in the blending method to sufficiently bring out the magnetic characteristics.
【０００５】[0005]
【課題を解決するための手段】本発明者はＲ量の高いＲ
−Ｆｅ−Ｂ系合金粉末の耐酸化性を向上させることにつ
いて検討を行った結果、Ｆｅの代わりにＣｏを合金化さ
せることが有効であることを知見し本発明を完成するに
至った。すなわち本発明は、焼結体におけるＲ（希土類
元素）量をＲ1とした場合に、Ｒ量Ｒ2がＲ1＜Ｒ2である
Ｒ−Ｃｏ−Ｂ合金粉末（以下「高Ｒ粉末」）と、Ｒ量Ｒ
3がＲ1＞Ｒ3であるＲ−Ｆｅ−Ｂ合金粉末（以下「低Ｒ
粉末」）とを混合、成形したのち焼結することを特徴と
する。以下本発明を詳述する。本願発明の最大の特徴
は、Ｆｅに比べて耐酸化性に優れるＣｏを高Ｒ粉末に合
金化させてＲ−Ｃｏ−Ｂ合金とすることにより従来の高
Ｒ粉末に比べ耐酸化性を向上した点にある。その結果、
高Ｒ粉末の低酸素化により磁気特性の劣下を抑制でき
る。また、Ｃｏは焼結後には主相であるＲ2Ｆｅ14Ｂよ
りもいわゆるＲrich相に多く分配され耐食性向上に寄与
する。本発明における高Ｒ粉末のＣｏの含有量は、後述
する低Ｒ粉末との混合量等によって変動するものであり
単純に定めることはできないが、焼結体の最終組成とし
て１５％以下となるように含有させることが望まれる。
１５％を越えると磁気特性を著しく劣下させるからであ
る。なお、本発明の主旨を逸脱しない範囲で本発明の高
Ｒ粉末にＦｅを加えることも許容される。The inventors of the present invention have found that the R content is high.
As a result of studying to improve the oxidation resistance of —Fe—B alloy powder, it was found that alloying Co instead of Fe is effective, and the present invention has been completed. That is, the present invention provides a R (rare earth element) amount in the sintered body in the case of the R 1, R-Co-B alloy powder content of R and R 2 is R 1 <R 2 (hereinafter "high R powder") And R amount R
R-Fe-B alloy powder in which 3 is R 1 > R 3 (hereinafter referred to as “low R
Powder)), mixed and shaped, and then sintered. The present invention will be described in detail below. The most important feature of the present invention is that Co, which is more excellent in oxidation resistance than Fe, is alloyed with a high R powder to form an R-Co-B alloy, which improves the oxidation resistance as compared with the conventional high R powder. In point. as a result,
Deterioration of magnetic properties can be suppressed by reducing the oxygen content of the high R powder. Further, after sintering, Co is distributed more in the so-called Rrich phase than in the main phase R 2 Fe 14 B and contributes to the improvement of corrosion resistance. The Co content of the high R powder in the present invention varies depending on the mixing amount with the low R powder described later and cannot be simply determined, but the final composition of the sintered body should be 15% or less. It is desirable to include in
This is because if it exceeds 15 % , the magnetic properties are remarkably deteriorated. It should be noted that addition of Fe to the high R powder of the present invention is allowed within a range not departing from the gist of the present invention.
【０００６】一方、低Ｒ粉末は酸化し易いＲの量が少な
いので、本発明の高Ｒ粉末と同様低酸素化が可能であ
る。本発明はこの低Ｒ粉末とＣｏを合金化させることに
より耐酸化性の向上した高Ｒ粉末とを混合するため従来
のブレンド法にくらべて低酸素化が可能となり、ひいて
は磁石の磁気特性を向上させる。本発明による磁石の最
終組成としては、前記特開昭５９−４６００８号に開示
されるように、Ｒ８〜３０ａｔ. ％、Ｂ２〜２８ａｔ.
％、残部Ｆｅの範囲とすればよい。また、Ｒ−Ｆｅ−Ｂ
系磁石でよく知られているＴｉ、Ｎｂ、Ｖ、Ｍｏ、Ａ
ｌ、Ｇａ等の元素を適宜含有せしめてもよい。本発明の
高および低Ｒ粉末は従来公知の方法により製造すること
ができる。例えば、真空または不活性ガス雰囲気下でア
ークまたは高周波加熱溶解によりインゴットを作成し、
これを粉砕する。粉砕は、粗粉砕と微粉砕の２段階で実
施され、粗粉砕はジョークラッシャー、ロールミル等
を、また微粉砕はボールミル、ジェットミル等を用いる
ことができる。この際、粉末の酸化を防止するため粉砕
雰囲気を不活性ガスとすることができる。また、粉末成
形、焼結も従来公知の方法にしたがって行えばよい。焼
結温度は専ら１０００〜１１５０°Ｃの範囲でおこなわ
れ、その後適宜熱処理を行うことができる。On the other hand, since the low R powder has a small amount of R which easily oxidizes, it can be reduced in oxygen like the high R powder of the present invention. The present invention mixes this low R powder with high R powder having improved oxidation resistance by alloying Co, so that oxygen can be reduced as compared with the conventional blending method, and the magnetic characteristics of the magnet are improved. Let The final composition of the magnet according to the present invention is, as disclosed in the above-mentioned JP-A-59-46008, R8 to 30 at.% And B2 to 28 at.
%, And the balance Fe. In addition, R-Fe-B
Ti, Nb, V, Mo, A, which are well-known for system magnets
Elements such as l and Ga may be appropriately contained. The high and low R powders of the present invention can be manufactured by a conventionally known method. For example, create an ingot by arc or high frequency heating melting under vacuum or inert gas atmosphere,
Crush this. The pulverization is carried out in two stages of coarse pulverization and fine pulverization. A jaw crusher, a roll mill or the like can be used for the coarse pulverization, and a ball mill, a jet mill or the like can be used for the fine pulverization. At this time, the crushing atmosphere can be an inert gas in order to prevent the powder from being oxidized. Further, powder molding and sintering may be performed according to a conventionally known method. The sintering temperature is exclusively in the range of 1000 to 1150 ° C., and then heat treatment can be appropriately performed.
【０００７】[0007]
（実施例１）以下本発明を実施例に基づき説明する。ア
ルゴン雰囲気下でアーク溶解により表１に示す組成の合
金を得た。得られた合金をディスクミルで粗粉砕し、３
２メッシュ以下に調整後ジェットミル（粉砕媒体窒素ガ
ス）で微粉砕し、粒度３.９μm（F.S.S.S）の微粉末を
得た。なお粗粉砕後および微粉砕後の含有酸素量を表１
に併せて記載する。(Example 1) Hereinafter, the present invention will be described based on examples. Alloys having the compositions shown in Table 1 were obtained by arc melting in an argon atmosphere. The obtained alloy is coarsely crushed by a disc mill and 3
After adjusting to 2 mesh or less, finely pulverized with a jet mill (nitrogen gas as a pulverizing medium) to obtain fine powder having a particle size of 3.9 μm (FSSS). Table 1 shows the oxygen content after coarse pulverization and after fine pulverization.
It is also described in.
【０００８】[0008]
【表１】 [Table 1]
【０００９】表１から、記号Ａ〜Ｄで示されるＣｏを含
む高Ｒ粉末は記号Ｅで示されるＣｏを含まない高Ｒ粉末
に比べて微粉砕後の酸素含有量が少ないことがわかる。
次に表１の記号ａ〜Ｅの粉末を表２に示す組合わせおよ
び割合で混合した後成形した。成形は、成形圧２トン／
cm2、磁場１０ｋＯｅの条件で行った。これらの成形体
を真空中で１０８０°Ｃで２時間焼結した。さらに焼結
体に、真空中で９００°Ｃで２時間保持した後、１.４
°Ｃ／min.の冷却速度で３００°Ｃ以下まで冷却し、さ
らにＡｒ雰囲気中で５７０°Ｃで１時間保持した後５０
°Ｃ／min.の冷却速度で４５０°Ｃまで冷却し、その後
室温まで冷却する熱処理を施した。 熱処理後、焼結体
の酸素含有量および磁気特性を測定した。結果を表２に
示すが、Ｃｏを含む高Ｒ粉末を用いた本発明による磁石
はＣｏを含まない高Ｒ粉末を用いた従来の磁石に比べ酸
素量が低く、磁気特性も向上している。From Table 1, it can be seen that the high R powder containing Co represented by the symbols A to D has a smaller oxygen content after fine pulverization than the high R powder containing no Co represented by the symbol E.
Next, the powders of symbols a to E in Table 1 were mixed in the combinations and proportions shown in Table 2 and then molded. Forming pressure is 2 tons /
The measurement was performed under the conditions of cm 2 and magnetic field of 10 kOe. These compacts were sintered in vacuum at 1080 ° C for 2 hours. Furthermore, after holding the sintered body at 900 ° C for 2 hours in vacuum, 1.4
After cooling to 300 ° C or less at a cooling rate of ° C / min., And further holding at 570 ° C for 1 hour in Ar atmosphere, 50
A heat treatment of cooling to 450 ° C at a cooling rate of ° C / min. And then to room temperature was performed. After the heat treatment, the oxygen content and magnetic properties of the sintered body were measured. The results are shown in Table 2. The magnet according to the present invention using the high R powder containing Co has a lower oxygen content and improved magnetic characteristics as compared with the conventional magnet using the high R powder not containing Co.
【００１０】[0010]
【表２】 [Table 2]
【００１１】表２より、高Ｒ粉末にＣｏを含有させない
従来磁石は酸素含有量が３０００ppmを越え(BH)maxも４
０ＭＧＯｅ以下であるのに対し、高Ｒ粉末にＣｏを含有
させた本発明にかかる磁石は酸素含有量が３０００ppm
以下で(BH)maxも４４ＭＧＯｅを越えている。 （実施例２）アルゴン雰囲気下でアーク溶解により表３
に示す組成の合金を得た後、実施例１と同様に粒度３.
９μm（F.S.S.S）の微粉末を得た。From Table 2, it can be seen that the conventional magnet not containing Co in the high R powder has an oxygen content exceeding 3000 ppm and a (BH) max of 4 as well.
In contrast to 0 MGOe or less, the oxygen content of the magnet according to the present invention containing Co in the high R powder is 3000 ppm.
Below, (BH) max also exceeds 44 MGOe. (Example 2) Table 3 was obtained by arc melting under an argon atmosphere.
After obtaining the alloy having the composition shown in FIG.
A fine powder of 9 μm (FSSS) was obtained.
【００１２】[0012]
【表３】 [Table 3]
【００１３】次に表３の記号ｆ〜Ｉの粉末を表４に示す
組合わせおよび割合で混合した後、実施例１と同様にし
て焼結体を得た。熱処理後、焼結体の酸素含有量および
磁気特性を測定した。結果を表４に示す。Next, the powders of symbols f to I in Table 3 were mixed in the combinations and proportions shown in Table 4, and then a sintered body was obtained in the same manner as in Example 1. After the heat treatment, the oxygen content and magnetic properties of the sintered body were measured. The results are shown in Table 4.
【００１４】[0014]
【表４】 [Table 4]
【００１５】[0015]
【発明の効果】以上説明のように、本発明によれば合金
粉末の酸化を極力防止して磁気特性を十分に引き出すこ
とのできる永久磁石の製造方法が提供される。As described above, according to the present invention, there is provided a method for producing a permanent magnet which can prevent the alloy powder from being oxidized as much as possible and bring out the magnetic characteristics sufficiently.
Claims (2)
1とした場合に、Ｒ量Ｒ2がＲ1＜Ｒ2であるＲ−Ｃｏ−Ｂ
合金粉末と、Ｒ量Ｒ3がＲ1＞Ｒ3であるＲ−Ｆｅ−Ｂ合
金粉末とを混合、成形したのち焼結することを特徴とす
る希土類永久磁石の製造方法。1. The amount of R (rare earth element) in the sintered body is R
When R is 1 , R-Co-B in which R amount R 2 is R 1 <R 2
And alloy powder, R amount R 3 is R 1> R 3 a is R-Fe-B mixed with alloy powder, method for preparing a rare earth permanent magnet, which comprises sintering After molding.
1とした場合に、Ｒ量Ｒ2がＲ1＜Ｒ2であるＲ−Ｆｅ−Ｃ
ｏ−Ｂ合金粉末と、Ｒ量Ｒ3がＲ1＞Ｒ3であるＲ−Ｆｅ
−Ｂ合金粉末とを混合、成形したのち焼結することを特
徴とする希土類永久磁石の製造方法。2. The amount of R (rare earth element) in the sintered body is R
When R is 1 , R-Fe-C in which the R amount R 2 is R 1 <R 2.
and o-B alloy powder, R amount R 3 is R 1> R 3 R-Fe
-A method for producing a rare earth permanent magnet, which comprises mixing with B alloy powder, shaping and sintering.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4238334A JPH0684623A (en) | 1992-09-07 | 1992-09-07 | Production of rare earth permanent magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4238334A JPH0684623A (en) | 1992-09-07 | 1992-09-07 | Production of rare earth permanent magnet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0684623A true JPH0684623A (en) | 1994-03-25 |
Family
ID=17028665
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4238334A Pending JPH0684623A (en) | 1992-09-07 | 1992-09-07 | Production of rare earth permanent magnet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0684623A (en) |
-
1992
- 1992-09-07 JP JP4238334A patent/JPH0684623A/en active Pending
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