JPH0997730A - Manufacture of sintered permanent magnet - Google Patents
Manufacture of sintered permanent magnetInfo
- Publication number
- JPH0997730A JPH0997730A JP7252133A JP25213395A JPH0997730A JP H0997730 A JPH0997730 A JP H0997730A JP 7252133 A JP7252133 A JP 7252133A JP 25213395 A JP25213395 A JP 25213395A JP H0997730 A JPH0997730 A JP H0997730A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- powder
- permanent magnet
- magnet
- orientation
- 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
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
- H01F41/0273—Imparting anisotropy
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Powder Metallurgy (AREA)
- Hard Magnetic Materials (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は焼結永久磁石の製造
方法に関し、特に高特性の希土類焼結磁石の製造に係る
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sintered permanent magnet, and more particularly to the production of a high-performance rare earth sintered magnet.
【０００２】[0002]
【従来の技術】粉末冶金法による永久磁石の磁気特性
は、一義的には磁石の素材ならびに組成によるが、製造
工程の種々の要因により影響を受ける。例えば、粉砕粒
度や粉末粒度分布、粉末配向度、焼結温度やパターン、
熱処理条件、焼結熱処理雰囲気、加工精度などである。
このなかで、磁石粉末の磁場中圧粉成形に起因する磁石
粉末の配向度は、特に重要である。2. Description of the Related Art The magnetic characteristics of a permanent magnet produced by powder metallurgy are primarily influenced by the material and composition of the magnet, but are influenced by various factors in the manufacturing process. For example, crushed particle size and powder particle size distribution, powder orientation degree, sintering temperature and pattern,
The heat treatment conditions, the sintering heat treatment atmosphere, the processing accuracy, and the like.
Among them, the degree of orientation of the magnet powder due to the powder compaction of the magnet powder in the magnetic field is particularly important.
【０００３】永久磁石粉末の磁場中圧粉成形には、配向
磁場方向と圧粉成形方向により、縦磁場成形と横磁場成
形の方法があることは周知である。横磁場成形では、配
向磁場方向と圧粉成形方向は直交しており、磁場中で配
向した磁石粉末は、圧粉成形過程で配向が乱れる度合い
は少ない。一方、縦磁場成形では、配向磁場方向と圧粉
成形方向は平行で、磁場中で配向した磁石粉末は、圧粉
成形過程で配向がかなり乱れる。磁石粉末の種類によ
り、配向乱れによる特性低下の程度は異なるが、例えば
NdFeB磁石では同じ磁石粉末を使用しても、横磁場成形
に比較し、縦磁場成形では10％以上特性が低下する。It is well known that, in the magnetic field compaction of permanent magnet powder, there are a longitudinal magnetic field compaction method and a transverse magnetic field compaction method depending on the orientation magnetic field direction and the compaction compaction direction. In the transverse magnetic field molding, the orientation magnetic field direction and the powder compacting direction are orthogonal to each other, and the magnet powder oriented in the magnetic field is less likely to be disturbed in the powder compacting process. On the other hand, in the vertical magnetic field molding, the orientation magnetic field direction and the powder compacting direction are parallel, and the orientation of the magnet powder oriented in the magnetic field is considerably disturbed in the powder compacting process. Depending on the type of magnet powder, the degree of property deterioration due to orientation disorder will differ.
Even if the same magnet powder is used for NdFeB magnets, the characteristics deteriorate by 10% or more in longitudinal magnetic field molding as compared with transverse magnetic field molding.
【０００４】縦磁場成形は、軸方向に磁化が向いたモー
タ用のリング状磁石などを作製するには必要不可欠であ
り、圧粉過程での配向乱れの改善が切望されている。こ
の配向乱れを改善するため、色々な磁場中成形方法が提
案されている。本発明者らは、先にパルス磁場とパルス
圧力の採用により、パルス磁場の高いピーク磁場を利用
して、パルス磁場印加時間内に圧粉成形を完了するパル
ス成形法を提案した。これによれば短時間で成形が完了
する上、通常の電磁石による磁場よりずっと高い磁場
（ただしピーク磁場で20ｋＯｅ以上）中で成形が可能な
ため、磁石配向の乱れを抑制し、横磁場同等の配向度を
実現できる。Longitudinal magnetic field molding is indispensable for producing a ring-shaped magnet for a motor whose magnetization is oriented in the axial direction, and improvement of orientation disorder in the powder compacting process is desired. In order to improve this alignment disorder, various magnetic field molding methods have been proposed. The present inventors have previously proposed a pulse molding method in which a powder magnetic field is applied within a time period of applying a pulse magnetic field by using a peak magnetic field having a high pulse magnetic field by employing a pulse magnetic field and a pulse pressure. According to this, molding is completed in a short time, and since it is possible to mold in a magnetic field much higher than the magnetic field of an ordinary electromagnet (however, at a peak magnetic field of 20 kOe or more), disturbance of the magnet orientation is suppressed, and a transverse magnetic field equivalent to A degree of orientation can be realized.
【０００５】しかし、この方法はパルス圧力を使用して
いるため、圧粉成形のプレス条件を微調整することが難
しく、成形体の健全性に問題があった。つまり、割れや
クラックなどの発生しやすく、成形可能な形状にも制限
があった。However, since this method uses pulse pressure, it is difficult to finely adjust the pressing conditions for powder compacting, and there is a problem with the soundness of the compact. That is, cracks and cracks are likely to occur, and the shape that can be molded is also limited.
【０００６】これに対して、パルス磁場で磁石粉末の配
向は行うが、圧粉成形は通常の油圧または機械圧により
行う方法が提案されている。しかし、該方法では、圧粉
成形は時間がかかるため、パルス磁場と圧粉成形を同期
させて行うことはできない。従って、圧粉成形過程では
磁場が印加されていないため、磁石粉末の配向は大幅に
乱れ、配向度の向上はできなかった。これを改善するた
め、パルス磁場を印加し、その後静磁場を印加して圧粉
成形を行うことも提案されている。しかし、この圧粉成
形過程では、従来と同じ磁場強度しか印加できないた
め、配向度の向上はあまり見られなかった。On the other hand, a method has been proposed in which the magnet powder is oriented by a pulsed magnetic field, but the powder compaction is performed by ordinary hydraulic pressure or mechanical pressure. However, in this method, since the powder compacting takes time, it is impossible to perform the pulse magnetic field and the powder compacting in synchronization. Therefore, since no magnetic field was applied during the powder compaction process, the orientation of the magnet powder was significantly disturbed, and the degree of orientation could not be improved. In order to improve this, it has been proposed to apply a pulsed magnetic field and then a static magnetic field to perform powder compaction. However, in this powder compacting process, only the same magnetic field strength as in the past can be applied, so that the degree of orientation has not been improved so much.
【０００７】最近、ゴム型静水圧成形法が佐川らによっ
て提案された。この方法では、ダイ金型中にゴム型を挿
入し、磁石粉末を充填した後、蓋をして、パルス磁場を
印加して磁石粉末を配向させた後、上パンチで圧粉成形
を行うと、ゴム型はダイ金型中で等方的に圧縮され、磁
石粉末は等方的に圧粉される。したがって、圧粉成形過
程では磁場が印加されていなくても、磁石粉末の配向は
ほとんど乱れる事なく成形される。この方法では、横磁
場成形と同等以上の配向度が実現され、リング形状を含
めほとんどの磁石形状を実現することが可能である。Recently, a rubber-type hydrostatic molding method has been proposed by Sagawa et al. In this method, a rubber die is inserted into a die die, magnet powder is filled, a lid is placed, a pulse magnetic field is applied to orient the magnet powder, and then powder compacting is performed with an upper punch. The rubber mold is isotropically compressed in the die mold, and the magnet powder is isotropically pressed. Therefore, even if a magnetic field is not applied in the powder compacting process, the orientation of the magnet powder is compacted without being disturbed. With this method, an orientation degree equal to or higher than that of transverse magnetic field shaping can be realized, and almost any magnet shape including a ring shape can be realized.
【０００８】しかし、従来のダイ金型成形とはかなり工
程が異なるため、プレス成形機は、従来の油圧成形機や
機械成形機が使用できず、新たなプレス成形機を用意し
なければならない。さらにこの方法の提案者は、多段ス
テージの磁場成形機を発表している。この方法は配向度
向上には優れた方法であるが、成形可能な形状に制限が
あり、多数個成形が一度にできないため現行のダイ金型
成形ほどの汎用性はない。However, since the process is considerably different from the conventional die mold molding, the conventional hydraulic molding machine or mechanical molding machine cannot be used as the press molding machine, and a new press molding machine must be prepared. Furthermore, the proposer of this method has announced a multi-stage magnetic field forming machine. Although this method is an excellent method for improving the degree of orientation, it is not as versatile as the current die mold molding because there is a limitation on the shape that can be molded and it is not possible to mold many pieces at once.
【０００９】[0009]
【発明が解決しようとする課題】本発明は、磁石粉末の
圧粉成形過程における、配向度低下の原因を考察し、従
来技術を基本的に踏まえながら、従来の縦磁場成形を改
良し、配向度の向上を計り、任意の磁石形状の圧粉成形
を実現しようとするものである。DISCLOSURE OF THE INVENTION The present invention considers the cause of the decrease in the degree of orientation during the powder compaction process of magnet powder, and improves the conventional longitudinal magnetic field compaction by fundamentally considering the prior art. It aims to realize powder compacting in an arbitrary magnet shape by improving the degree.
【００１０】本発明は、従来の縦磁場成形における問題
点を解決し、配向度の向上を計り、かつ機械要素として
は従来方法をできるだけ踏襲することによって、任意の
磁石形状の圧粉成形を実現しようとするものである。The present invention solves the problems in the conventional longitudinal magnetic field molding, improves the degree of orientation, and follows the conventional method as a mechanical element to realize powder compacting in an arbitrary magnet shape. Is what you are trying to do.
【００１１】[0011]
【課題を解決するための手段】本発明は、縦磁場成形に
おいて、パルス磁場と従来型のダイ金型成形機を使用す
るものであって、その要旨は、粉末焼結法による永久磁
石の製造方法において、永久磁石粉末をダイ金型に充填
し、粉末充填見かけ密度が30％以上50％以下の状態で、
ピーク磁場が20ｋＯｅ以上で、ピーク磁場の半値幅が１
msec以上 500msec以下にあるパルス磁場を印加し、該永
久磁石粉末を磁場方向に配向させた後、１軸圧にて圧粉
成形を行う焼結永久磁石の製造方法にある。DISCLOSURE OF THE INVENTION The present invention uses a pulsed magnetic field and a conventional die mold molding machine in the longitudinal magnetic field molding, and the gist thereof is the production of a permanent magnet by a powder sintering method. In the method, the die magnet is filled with permanent magnet powder, and the powder filling apparent density is 30% or more and 50% or less,
The peak magnetic field is 20 kOe or more, and the half width of the peak magnetic field is 1
This is a method for producing a sintered permanent magnet, in which a pulsed magnetic field of at least msec and no more than 500 msec is applied, the permanent magnet powder is oriented in the magnetic field direction, and then powder compacting is performed with uniaxial pressure.
【００１２】縦磁場圧粉成形過程における配向度の低下
は、数珠状に配向した磁石粉末列を押し崩しながら圧粉
成形することにより生じるのに対して、横磁場プレスで
は、数珠状に配向した磁石粉末列を崩すことなく、平行
移動するような形で圧粉成形を行うため、配向度の低下
が少ないと考えられる。パルス磁場の高いピーク磁場を
印加すると、磁石粉末が圧粉成形過程で移動しても、高
い磁場強度により磁場印加方向に揃えられるため、配向
度の低下が少なく、横磁場成形と同等の配向度が実現で
きるものと考えられる。The decrease in the degree of orientation in the vertical magnetic powder compaction process occurs when powder compaction is performed while the magnet powder row oriented in a beaded shape is collapsed, whereas in the transverse magnetic field press, it is oriented in a beaded shape. It is considered that the degree of orientation is not significantly reduced because the powder compaction is performed in such a manner as to move in parallel without breaking the magnet powder row. When a high peak magnetic field with a pulsed magnetic field is applied, even if the magnet powder moves during the powder compaction process, the magnetic field is aligned in the direction of the magnetic field application due to the high magnetic field strength, so the degree of orientation does not decrease, and the degree of orientation is similar to that of transverse magnetic field shaping. It is thought that can be realized.
【００１３】したがって、縦磁場成形で配向度の向上を
はかるためには、圧粉成形過程での高磁場印加が必須で
ある。これに対し、ゴム型静水圧成形においては、パル
ス磁場印加の前に、ゴム型中の磁石粉末を軽く圧粉して
型中の見かけ密度を上げておいて、パルス磁場を印加す
る。これは、ゴム型を利用した圧粉成形で起きる「象の
足」現象をなくすため、ゴム型の変形量をできるだけ少
なくする必要があるためである。また、該圧粉成形法に
おいて、圧粉成形過程で磁場が印加されていないにも関
わらず、磁石粉末の配向が乱れないのは、等方的に圧粉
成形されるためであると考えられている。Therefore, in order to improve the degree of orientation in the vertical magnetic field molding, it is essential to apply a high magnetic field in the powder compacting process. On the other hand, in the rubber-type hydrostatic molding, before applying the pulse magnetic field, the magnetic powder in the rubber mold is lightly pressed to increase the apparent density in the mold, and then the pulse magnetic field is applied. This is because it is necessary to reduce the amount of deformation of the rubber mold as much as possible in order to eliminate the "elephant's foot" phenomenon that occurs in compaction molding using a rubber mold. Further, in the powder compacting method, the orientation of the magnet powder is not disturbed even though no magnetic field is applied in the powder compacting process, which is considered to be due to isotropic powder compacting. ing.
【００１４】しかし、本発明者はゴム型静水圧成形につ
いて種々の考察・実験を進めた結果、圧粉成形過程にお
ける配向度の乱れが少ない原因は、必ずしも静水圧成形
によるものではなく、パルス磁場印加の前に見かけ密度
を高くしているので、磁石粉末の圧粉過程における移動
量が小さい事に起因するものであることを見いだした。
通常の電磁石を利用した磁場中成形では、印加できる磁
場強度は、希土類磁石の場合でも高々10ｋＯｅ〜15ｋＯ
ｅである。したがって、ダイ金型中への磁石粉末の充填
見かけ密度は、真密度の約30％以下でなければならなか
った。However, as a result of various studies and experiments on the rubber type hydrostatic molding, the present inventor has found that the cause of the less disorder of the orientation degree in the powder compacting process is not necessarily due to the hydrostatic molding, but the pulse magnetic field. Since the apparent density was made high before the application, it was found that it was caused by the small movement amount of the magnet powder in the powder compaction process.
In the magnetic field molding using an ordinary electromagnet, the magnetic field strength that can be applied is at most 10 kOe to 15 kO even in the case of a rare earth magnet.
It is e. Therefore, the apparent density of the magnet powder packed in the die mold had to be about 30% or less of the true density.
【００１５】これ以上の見かけ密度の場合、磁石粉末は
磁場印加方向に十分配向せず、磁気特性の低下が起こっ
た。真密度の30％以下の充填状態での圧粉成形では、磁
石粉末は圧粉過程で大きな距離を移動し、移動距離が大
きいほど配向度の低下も大きい。When the apparent density was higher than the above value, the magnet powder was not sufficiently oriented in the magnetic field application direction, resulting in deterioration of magnetic properties. In compaction molding in a filling state of 30% or less of the true density, the magnet powder moves a large distance in the compaction process, and the longer the movement distance, the greater the decrease in orientation degree.
【００１６】本発明は磁場印加前の事前圧粉を行い、で
きるだけ見かけ密度を向上させた状態で、磁石粉末を磁
場印加方向に回転配向させるに十分なパルス磁場を印加
し、これを従来のダイ金型中で圧粉成形するのである。
事前圧粉後の見かけ密度は、高ければ高い程望ましい
が、磁石粉末を配向させるには、より高いパルス磁場が
必要なため、ダイ金型への充填見かけ密度は50％以下が
必要である。また、充填見かけ密度が30％以下では、圧
粉成形過程での配向度低下が大きくなるため、それ以上
である必要がある。According to the present invention, pre-compacting is performed before applying a magnetic field, and a pulse magnetic field sufficient to rotationally orient the magnet powder in the magnetic field application direction is applied in a state where the apparent density is improved as much as possible. It is compacted in a mold.
The higher the apparent density after the pre-compaction is, the more preferable, but a higher pulse magnetic field is required for orienting the magnet powder, and therefore the apparent density of filling the die is 50% or less. Further, if the apparent density of filling is 30% or less, the degree of orientation reduction in the powder compacting process becomes large, and therefore it is necessary to be more than that.
【００１７】事前圧粉された磁石粉末を配向させるのに
十分なパルス磁場強度は、充填見かけ密度により異なる
が、ピーク強度で20ｋＯｅ以上が必要で、望ましくは、
30ｋＯｅ以上がよい。パルス磁場は、ダイ金型の外側に
空芯コイルなどを設置することにより発生される。The pulse magnetic field strength sufficient to orient the pre-compacted magnet powder depends on the apparent density of the packing, but a peak strength of 20 kOe or more is required.
30 kOe or more is good. The pulsed magnetic field is generated by installing an air core coil or the like outside the die die.
【００１８】このため、ピーク値までの立ち上がり時間
の短いパルス磁場では、金型中に渦電流が発生し、パル
ス磁束が金型空隙中に十分浸透しない。このため、パル
ス磁場の半値幅は１msec以上が必要である。パルス磁場
の半値幅はできるだけ長い方が望ましいが、長すぎると
パルス電源のコンデンサー容量を大きくしたり、空芯コ
イル巻き数を多くしなければならないため、電源が非常
に大きく高価になったり、コイル巻き数が多いため磁場
印加後にコイル温度が上昇し、なかなかコイル内温度が
低下しない。したがって、パルス磁場の半値幅は 500ms
ec以下であることが望ましい。もっとも望ましいパルス
磁場の半値幅は、５msec〜50msecである。Therefore, in a pulse magnetic field having a short rise time to the peak value, an eddy current is generated in the mold, and the pulse magnetic flux does not sufficiently penetrate into the mold cavity. Therefore, the full width at half maximum of the pulsed magnetic field needs to be 1 msec or more. It is desirable that the full width at half maximum of the pulse magnetic field is as long as possible, but if it is too long, the capacitor capacity of the pulse power supply must be increased and the number of air core coil windings must be increased, so the power supply becomes very large and expensive, and the coil Since the number of turns is large, the coil temperature rises after the magnetic field is applied, and the temperature inside the coil does not easily fall. Therefore, the full width at half maximum of the pulsed magnetic field is 500 ms.
It is desirable to be ec or less. The most desirable half-value width of the pulse magnetic field is 5 msec to 50 msec.
【００１９】圧粉成形機は、基本的には従来と同じ油圧
や機械圧による１軸成形機でよい。電磁石の代わりに、
パルス磁場を発生させるため空芯コイルとパルス電源が
必要である。空芯コイルの内部にダイ金型を挿入する。
従来の圧粉成形法では、上パンチは磁石粉末が充填され
たダイ金型の上面位置まで下降し、一度停止した状態
で、電磁石により磁場が印加され、磁石粉末を磁場方向
に配向した後、磁場を印加した状態で、上パンチを下降
し、ダイ金型中の磁石粉を圧粉成形した。本発明では、
上パンチは下降し、磁石粉末が充填されたダイ金型中に
途中まで挿入され、事前圧粉を行う。その状態で一度上
パンチは停止し、パルス磁場が印加され、磁石粉末を配
向させたのち、上パンチを更に挿入して、最終圧粉成形
を行う。The powder compacting machine may basically be a uniaxial molding machine using the same hydraulic pressure or mechanical pressure as in the conventional case. Instead of an electromagnet,
An air-core coil and a pulse power supply are required to generate a pulsed magnetic field. Insert the die mold inside the air core coil.
In the conventional powder compacting method, the upper punch descends to the upper surface position of the die die filled with magnet powder, and once stopped, a magnetic field is applied by an electromagnet to orient the magnet powder in the magnetic field direction, With the magnetic field applied, the upper punch was lowered to compact the magnet powder in the die mold. In the present invention,
The upper punch descends and is inserted halfway into a die die filled with magnet powder to perform pre-compaction. In that state, the upper punch is once stopped, a pulsed magnetic field is applied to orient the magnet powder, and then the upper punch is further inserted to perform final powder compaction.
【００２０】パルス磁場以外は従来の機械装置を使用す
るため、機械要素の特別な開発や改造は必要なく、安定
して任意の大きさの健全な成形体を製作する事が可能で
ある。最終圧粉成形過程において、基本的に静磁場印加
は必要ないが、静磁場を印加しておいた方が、配向度の
低下はより少なくなる。最終圧粉成形過程で、パルス磁
場を複数印加することも考えられるが、パルス磁場と成
形圧を同期させることはできないし、時間幅も異なるの
で効果は少ない。Since conventional mechanical devices are used except for the pulsed magnetic field, no special development or modification of mechanical elements is required, and it is possible to stably produce a sound compact of any size. Basically, it is not necessary to apply a static magnetic field in the final powder compacting process, but if a static magnetic field is applied, the degree of orientation will decrease less. It is possible to apply a plurality of pulse magnetic fields in the final powder compacting process, but it is not effective because the pulse magnetic fields and the compacting pressure cannot be synchronized and the time widths are different.
【００２１】本発明は、磁石粉末一般に適用可能である
が、磁場配向に高い磁場強度の必要な希土類磁石粉末の
配向に最適である。希土類磁石には、１−５SmCo磁石、
２−17SmCo磁石、 NdFeB磁石などがあるが、これら全て
に適用可能なものである。The present invention is applicable to magnet powders in general, but is most suitable for the orientation of rare earth magnet powders which require high magnetic field strength for magnetic field orientation. Rare earth magnets include 1-5SmCo magnets,
There are 2-17SmCo magnets, NdFeB magnets, etc., but they are applicable to all of them.
【００２２】[0022]
【発明の実施の形態】本発明の実施の形態について、実
施例、比較例を挙げて説明する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to Examples and Comparative Examples.
【００２３】[0023]
実施例１〜４、比較例、 Ｎｄ、Ｆｅの金属とＦｅＢ合金とを原子百分比でNd15Fe
78B7となるように秤量し、その後真空溶解炉で合金を作
製した。該合金を機械粉砕で20メッシュ以下に粗粉砕
し、引き続き高圧Ｎ2 ガスを用いたジェットミルで、平
均粒径４μｍになるように微粉砕した。該微粉をダイプ
レス金型に充填し、磁場を印加する前の見かけ密度を20
％から60％まで変えた。その後、ピーク磁場が40ｋＯｅ
で、パルス半値幅が10msecのパルス磁場を印加して金型
内部に充填した微粉を配向させた後、上パンチをダイス
内に押し込んで、圧粉成形を行った。Examples 1 to 4, Comparative example, Nd 15 Fe metal and FeB alloy in atomic percentage of Nd 15 Fe
It was weighed to be 78 B 7, and then an alloy was prepared in a vacuum melting furnace. The alloy was roughly pulverized to 20 mesh or less by mechanical pulverization, and then finely pulverized by a jet mill using high pressure N 2 gas so that the average particle size was 4 μm. The fine powder was filled in a die press die, and the apparent density before applying a magnetic field was 20
Changed from 60% to 60%. After that, the peak magnetic field is 40 kOe
Then, after applying a pulse magnetic field having a pulse half-value width of 10 msec to orient the fine powder filled in the mold, the upper punch was pushed into the die to perform powder compaction.
【００２４】取り出した成形体は、Ａｒガス中で 1,100
℃で１時間焼結を行い、引き続き 580℃で１時間熱処理
を行って、焼結体を得た。ついで、これらの焼結体をＢ
Ｈトレーサーで磁気特性を測定した結果を表１に示す。The molded body taken out was treated with 1,100 in Ar gas.
Sintering was performed at 1 ° C for 1 hour, and then heat treatment was performed at 580 ° C for 1 hour to obtain a sintered body. Then, these sintered bodies are
Table 1 shows the results of measuring the magnetic properties with the H tracer.
【００２５】比較例 比較のため、前記微粉を金型に見かけ密度25％に充填
し、10ｋＯｅの静磁場を印加し、該微粉を配向させた
後、磁場を印加したままで、圧粉成形を行い、焼結・熱
処理は実施例と同様に行い焼結体とし、ＢＨトレーサー
で磁気特性を測定した。その結果を表１に示す。Comparative Example For comparison, a mold was filled with the fine powder to an apparent density of 25%, a static magnetic field of 10 kOe was applied to orient the fine powder, and then the powder was compacted while the magnetic field was applied. The sintering and heat treatment were performed in the same manner as in the example to obtain a sintered body, and the magnetic characteristics were measured with a BH tracer. Table 1 shows the results.
【００２６】[0026]
【表１】 [Table 1]
【００２７】[0027]
【発明の効果】本発明の方法によれば、高特性の希土類
焼結磁石の製造ができ、ＤＣブラシレスモータやＡＣサ
ーボモータ、ステッピングモータなどに用いて最適な永
久磁石が得られる。According to the method of the present invention, it is possible to manufacture a high-performance rare earth sintered magnet, and it is possible to obtain an optimum permanent magnet for use in a DC brushless motor, an AC servomotor, a stepping motor, or the like.
Claims (4)
おいて、永久磁石粉末をダイ金型に充填し、粉末充填見
かけ密度が30％以上50％以下の状態で、ピーク磁場が20
ｋＯｅ以上で、ピーク磁場の半値幅が１msec以上 500ms
ec以下にあるパルス磁場を印加し、該永久磁石粉末を磁
場方向に配向させた後、１軸圧にて圧粉成形を行うこと
を特徴とする焼結永久磁石の製造方法。1. A method for manufacturing a permanent magnet by a powder sintering method, wherein a permanent magnet powder is filled in a die and the apparent density of powder filling is 30% or more and 50% or less, and a peak magnetic field is 20%.
At kOe or more, the half-width of the peak magnetic field is 1 msec or more and 500 ms
A method for producing a sintered permanent magnet, which comprises applying a pulsed magnetic field of ec or less to orient the permanent magnet powder in a magnetic field direction, and then performing powder compacting with uniaxial pressure.
方向に配向させた後、静磁場を印加した状態で、１軸圧
にて圧粉成形を行うことを特徴とする請求項１に記載の
焼結永久磁石の製造方法。2. The powder compaction is carried out with a uniaxial pressure in a state where a static magnetic field is applied after a pulsed magnetic field is applied to the permanent magnet powder to orient it in the magnetic field direction. Method for manufacturing a sintered permanent magnet according to.
方向が平行な縦磁場で成形することを特徴とする請求項
１に記載の焼結永久磁石の製造方法。3. The method for producing a sintered permanent magnet according to claim 1, wherein the permanent magnet powder is formed by a vertical magnetic field in which a magnetic field applying direction and a powder compacting direction are parallel to each other.
とを特徴とする請求項１〜３のいずれかに記載の焼結永
久磁石の製造方法。4. The method for producing a sintered permanent magnet according to claim 1, wherein the permanent magnet powder is a rare earth permanent magnet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7252133A JPH0997730A (en) | 1995-09-29 | 1995-09-29 | Manufacture of sintered permanent magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7252133A JPH0997730A (en) | 1995-09-29 | 1995-09-29 | Manufacture of sintered permanent magnet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0997730A true JPH0997730A (en) | 1997-04-08 |
Family
ID=17232944
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7252133A Pending JPH0997730A (en) | 1995-09-29 | 1995-09-29 | Manufacture of sintered permanent magnet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0997730A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006108591A (en) * | 2004-10-08 | 2006-04-20 | Tdk Corp | Rare-earth sintered magnet and manufacturing method therefor |
| US7416613B2 (en) | 2004-01-26 | 2008-08-26 | Tdk Corporation | Method for compacting magnetic powder in magnetic field, and method for producing rare-earth sintered magnet |
| CN103056371A (en) * | 2013-01-18 | 2013-04-24 | 徐州金石彭源稀土材料厂 | Technology for preparing neodymium-iron-boron permanent-magnet material with orientation length L>/=60mm |
-
1995
- 1995-09-29 JP JP7252133A patent/JPH0997730A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7416613B2 (en) | 2004-01-26 | 2008-08-26 | Tdk Corporation | Method for compacting magnetic powder in magnetic field, and method for producing rare-earth sintered magnet |
| JP2006108591A (en) * | 2004-10-08 | 2006-04-20 | Tdk Corp | Rare-earth sintered magnet and manufacturing method therefor |
| CN103056371A (en) * | 2013-01-18 | 2013-04-24 | 徐州金石彭源稀土材料厂 | Technology for preparing neodymium-iron-boron permanent-magnet material with orientation length L>/=60mm |
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