JPH02148704A - Method of demagnetizing rare-earth permanent magnet - Google Patents
Method of demagnetizing rare-earth permanent magnetInfo
- Publication number
- JPH02148704A JPH02148704A JP30199988A JP30199988A JPH02148704A JP H02148704 A JPH02148704 A JP H02148704A JP 30199988 A JP30199988 A JP 30199988A JP 30199988 A JP30199988 A JP 30199988A JP H02148704 A JPH02148704 A JP H02148704A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- magnet
- permanent magnet
- demagnetization
- rare earth
- 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
- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 40
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 37
- 238000000034 method Methods 0.000 title claims abstract description 16
- 230000002238 attenuated effect Effects 0.000 claims description 6
- 238000013016 damping Methods 0.000 claims description 2
- 230000004907 flux Effects 0.000 abstract description 11
- 238000004663 powder metallurgy Methods 0.000 abstract description 4
- 238000005191 phase separation Methods 0.000 abstract description 3
- 230000000694 effects Effects 0.000 abstract description 2
- 238000007669 thermal treatment Methods 0.000 abstract 1
- 230000005347 demagnetization Effects 0.000 description 44
- 230000005415 magnetization Effects 0.000 description 13
- 238000010438 heat treatment Methods 0.000 description 11
- 230000003068 static effect Effects 0.000 description 7
- 229910052742 iron Inorganic materials 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000002131 composite material Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000005381 potential energy Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 1
- 229910002549 Fe–Cu Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 238000000748 compression moulding Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Landscapes
- Hard Magnetic Materials (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、希土類永久磁石の減磁調整方法に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for adjusting demagnetization of rare earth permanent magnets.
（従来の技術）
永久磁石のフル（完全）着磁は、静磁場またはパルス磁
場で行い、フル着磁後減磁調整を着磁同様静磁場または
パルス磁場で行うのが一般的である。減磁調整する理由
は、永久磁石の減磁調整後のフラックスの熱的および逆
磁場に対する安定性を増加し、磁気回路のギャップフラ
ックスを成る値に調整し、または、その両方を満足させ
るためである。この磁石の安定性の増加は、反磁場の大
きさが減少するためである。また、焼結磁石の場合には
、保磁力の小さな結晶粒が脱磁されることにより減磁す
る要因が減少するためでもある。しかし、減磁調整では
、フル着磁の場合に比べて必要とされる磁場は小さいた
め、逆転した粒内の磁壁が準安定なポテンシャルにビン
止めされたり、磁壁の消去が不充分であったりすること
がある。(Prior Art) Full magnetization of a permanent magnet is generally performed using a static magnetic field or a pulsed magnetic field, and after full magnetization, demagnetization adjustment is generally performed using a static magnetic field or a pulsed magnetic field in the same way as magnetization. The reason for demagnetization adjustment is to increase the stability of the flux of the permanent magnet after demagnetization adjustment against thermal and reverse magnetic fields, to adjust the gap flux of the magnetic circuit to a value, or to satisfy both. be. This increase in magnet stability is due to the decrease in the magnitude of the demagnetizing field. In addition, in the case of a sintered magnet, crystal grains with a small coercive force are demagnetized, thereby reducing the factors that cause demagnetization. However, in demagnetization adjustment, the magnetic field required is smaller than in the case of full magnetization, so the domain walls within the reversed grains may be pinned to a metastable potential, or the domain walls may not be erased sufficiently. There are things to do.
このような場合、磁石の温度り月００℃以上に上昇した
り、減磁より強い逆磁場が掛かったりした時、大幅な減
磁または増磁を示すことがある。特に、減磁調整の割合
が大きい時、上記の傾向は顕著になる。準安定な粒を安
定にするため、例えば、減磁調整を行うパルス磁場を数
回掛けることも通常行われている。しかしこの方法では
、減磁調整に要する時間が長くなるためあまり好ましく
ない、交流磁場で行うのが好ましいが、希土類磁石では
着磁または減磁にも強力な磁場が必要なため試みられて
いなかった。In such cases, when the temperature of the magnet rises above 00° C. or when a reverse magnetic field stronger than demagnetization is applied, significant demagnetization or magnetization may occur. In particular, when the rate of demagnetization adjustment is large, the above tendency becomes remarkable. In order to stabilize metastable grains, for example, a pulsed magnetic field for demagnetization adjustment is usually applied several times. However, this method is not very desirable because it takes a long time to adjust the demagnetization.Although it is preferable to use an alternating magnetic field, it has not been attempted with rare earth magnets because they require a strong magnetic field to magnetize or demagnetize them. .
（発明が解決しようとする課題）
本発明の技術的課題は、上記した従来技術の欠点を解決
した希土類永久磁石の減磁方法を提供することにある。(Problems to be Solved by the Invention) A technical problem of the present invention is to provide a method for demagnetizing rare earth permanent magnets that solves the drawbacks of the prior art described above.
（課題を解決するための手段）
本発明はこのような欠点を解決した希土類永久磁石の減
磁方法に関するものであり、減磁調整を減衰型交流磁場
で行うことを要旨とするものである。すなわち、本発明
者等は、最も効率的で、減磁率の調整も容易と思われる
交流磁場に着目し検討した結果、減衰型交流磁場で特定
の減衰定数に調整することにより、希土類永久磁石のフ
ラックスの熱的および磁場に対する安定性が顕著に向上
することを見出し、本発明を完成した。(Means for Solving the Problems) The present invention relates to a method for demagnetizing rare earth permanent magnets that solves the above-mentioned drawbacks, and its gist is to perform demagnetization adjustment using an attenuated alternating current magnetic field. In other words, the inventors focused on the AC magnetic field, which is considered to be the most efficient and easy to adjust the demagnetization rate, and found that by adjusting the attenuation constant to a specific damping type AC magnetic field, it is possible to improve the We have completed the present invention by discovering that the stability of flux against thermal and magnetic fields is significantly improved.
以下、本発明を詳述する。The present invention will be explained in detail below.
まず本発明が適応される希土類永久磁石は、粉末冶金法
によって製造されたＮｄ系磁石、Ｓｍ系１−５磁石およ
び二相分離型磁石（紬糸２−１７磁石、Ｃｅ系磁石）な
どが挙げられる。First, rare earth permanent magnets to which the present invention is applied include Nd-based magnets, Sm-based 1-5 magnets, and two-phase separation type magnets (Pongee thread 2-17 magnets, Ce-based magnets), etc. manufactured by powder metallurgy. .
Ｎｄ系磁石はＲ，Ｆｅ、 Ｂを主体とし、８２Ｆ１３１
４８＋を化学量論比とする希土類磁石で、Ｒ−Ｆｅ−Ｂ
−Ｍから成り、ＲはＹを含も希土類元素全部の内の一種
または二種以上の複合組成であり、Ｆｅは一部をＣｏで
置換してもよく、Ｍは無添加か、Ａ１．Ｎｂ、Ｍｏ、Ｇ
ａ、Ｔｉ、Ｖ、Ｃｒ、Ｎｉ、Ｓｉ、Ｍｎの内一種またた
は二種以上添加したものである。 Ｓｍ系１−５磁石は
、Ｒ，Ｃｏを主体とし、 ＲＣｏａを化学量論比とする
希土類磁石で、ＲはＹを含む希土類元素全部の内の一種
または二種以上の複合組成磁石である。二相分離型磁石
（Ｓｍ系２１７ｍ石、Ｃｅ系磁石）はＲ、Ｃｏ、 Ｆｅ
、Ｃｕ、 Ｍを主体とし、組成式Ｒ（Ｃｏ−Ｆｅ−Ｃｕ
−Ｍ） 、 （ここにＺは４＜ｚ＜９）で表わされ、Ｒ
はＹを含む希土類元素全部の内の一種または二種以上の
複合組成で、ＭはＣｒ、Ｍｎ、Ｎｉ、Ｔｉ、Ｚｒ、Ｈｆ
、 Ｂの内の一種または二種以上を添加した希土類磁石
である１以上本発明の適応範囲を述べたが、希土類永久
磁石であれば、前述した範囲に限定されるものではない
。Nd-based magnets are mainly composed of R, Fe, and B, and are 82F131
A rare earth magnet with a stoichiometric ratio of 48+, R-Fe-B
-M, R is a composite composition of one or more of all rare earth elements including Y, Fe may be partially replaced with Co, and M is not added or A1. Nb, Mo, G
One or more of a, Ti, V, Cr, Ni, Si, and Mn are added. The Sm-based 1-5 magnet is a rare earth magnet mainly composed of R and Co, with RCoa as the stoichiometric ratio, and R is a composite composition magnet of one or more of all rare earth elements including Y. Two-phase separation type magnet (Sm-based 217m stone, Ce-based magnet) is R, Co, Fe
, Cu, and M, and has a compositional formula R (Co-Fe-Cu
-M), (here Z is expressed as 4<z<9), and R
is a composite composition of one or more of all rare earth elements including Y, M is Cr, Mn, Ni, Ti, Zr, Hf
, B is a rare earth magnet to which one or more of the above are added. However, as long as it is a rare earth permanent magnet, it is not limited to the above-mentioned range.
次ぎに、減磁方法について述べる。上記希土類永久磁石
を実用化するには、フル着磁し、次いで減磁調整を静磁
場またはパルス磁場（第１図ａ）で行うのが一般的であ
る。この減磁調整は、永久磁石のフラックスの熱的およ
び磁場に対する安定性を増大させ、また、磁気回路のギ
ャップフラックスを成る値に調整するため、またはその
両方を満足するために行うが、従来の静磁場またはパル
ス磁場での減磁方法では前記した理由により、減磁によ
って逆転した粒内で磁壁が準安定な状態になり、１００
℃以上の高温または減磁より強い逆磁場が掛かった時に
、大幅な減磁または増磁を示す本発明は、減磁調整後の
準安定な場所にビン止めされた磁壁を出来るだけ安定に
し、磁石のフラックスを安定化する方法を検討した結果
、振幅が徐々に減少していく減衰型交流磁場がこの目的
を達成することを見出した。この磁場により安定化する
理由は、縦軸にポテンシャルエネルギーを横軸に磁壁の
移動距離を採った第２図から理解される。すなわち、第
１図ａに示したパルス磁場の波形で減磁調整を行った場
合、第２図のように磁壁はＡからＢの準安定な状態に移
動する。これに対し、第１図すに示したような減衰交流
波形で減磁調整を行った場合は、磁壁はＢの位置まで移
動した後、更に、エネルギー的に交流振動を受け、Ｂの
準安定な状態からＣのエネルギー的に安定な位置に落込
み安定化することから、交流磁場での減磁調整が静磁場
またはパルス磁場を使用した減磁調整よりもより安定化
することが解る。Next, the demagnetization method will be described. In order to put the rare earth permanent magnet into practical use, it is common to fully magnetize it and then perform demagnetization adjustment using a static magnetic field or a pulsed magnetic field (FIG. 1a). This demagnetization adjustment is performed to increase the thermal and magnetic field stability of the permanent magnet flux and/or to adjust the gap flux of the magnetic circuit to a value of In the demagnetization method using a static magnetic field or a pulsed magnetic field, for the reasons mentioned above, the domain walls become metastable within the grains reversed by demagnetization, and the
The present invention, which shows significant demagnetization or magnetization when a high temperature of ℃ or higher or a reverse magnetic field stronger than demagnetization is applied, makes the domain wall pinned in a quasi-stable place after demagnetization adjustment as stable as possible, After investigating ways to stabilize the magnetic flux, they found that a damped alternating current magnetic field, whose amplitude gradually decreases, achieves this objective. The reason for stabilization due to this magnetic field can be understood from Figure 2, which plots the potential energy on the vertical axis and the moving distance of the domain wall on the horizontal axis. That is, when demagnetization adjustment is performed using the waveform of the pulsed magnetic field shown in FIG. 1a, the domain wall moves from A to B, a quasi-stable state, as shown in FIG. On the other hand, when demagnetization adjustment is performed using a damped AC waveform as shown in Figure 1, the domain wall moves to position B and then undergoes further energetic AC vibration, resulting in the quasi-stable state of B. It is understood that the demagnetization adjustment using an alternating magnetic field is more stable than the demagnetization adjustment using a static magnetic field or a pulsed magnetic field because the demagnetization adjustment occurs from a state where C falls to an energetically stable position and stabilizes.
さらに、減衰交流波形で、最初のピーク波高値の１ ／
ｅになる時１間（減衰定数で）を５ ｍｓｅｃ以上５
００ｍｓｅｃ以下とすることが好ましい、 ５ｍｓｅｃ
以下の短時間では減衰交流磁場に磁壁移動が追随できず
、パルス磁場を使用して減磁調整を行ったのと殆ど変わ
らず、５００ｍｓｅｃ以上では、交流磁場の減衰定数を
大きくするために必要な磁場発生器のコンデンサー容量
を必要以上に大型化しなければならず、コストが高くな
り過ぎる。Furthermore, in the attenuated AC waveform, 1 / of the first peak peak value
e time (attenuation constant) for 5 msec or more 5
00msec or less is preferable, 5msec
In the following short time periods, the domain wall movement cannot follow the attenuated AC magnetic field, which is almost the same as demagnetization adjustment using a pulsed magnetic field, and in the shorter time periods of 500 msec or more, the domain wall movement cannot follow the attenuation constant of the AC magnetic field. The capacitor capacity of the magnetic field generator must be made larger than necessary, and the cost becomes too high.
次ぎに、前述したＮｄ系、軸系およびＣｅ系希土類永久
磁石の粉末冶金法による製造方法を述べるが減磁調整方
法以外は公知の方法が適応される。まず磁石組成の金属
（Ｎｄ系はＮｄ、 Ｆｅ、 Ｂ他、Ｓｍ系はＳｍ、 Ｃ
ｏ、 Ｆｅ、 Ｃｏ他およびＣｅ系はＣｅ、 Ｃｏ、
Ｆｅ、 Ｃｏ他）を高周波溶解炉を用いて不活性ガス中
で溶解し、磁石インゴットを作成する。このインゴット
な粗砕機（ショークラッシャーまたはブラウンミル）で
粗粉砕し、ついでジェットミルで窒素中で平均粒径３μ
ｍまで微粉砕する。この微粉を磁場中で配向させ、１．
２ ｔ／ｃｍ”のプレス圧で圧縮成形する。この成形体
を１０−’Ｔｏｒｒの真空中で焼結炉によりＮｄ系では
１０９０℃、Ｓｍ系では１１８０℃、Ｃｅ系ではで１０
７０℃で１時間焼結し、この焼結体を時効処理にかけ磁
石化する。最後に減磁調整を行って製品とする。Next, a method for manufacturing the aforementioned Nd-based, axial-based, and Ce-based rare earth permanent magnets using a powder metallurgy method will be described, and known methods may be applied except for the demagnetization adjustment method. First, the metal of the magnet composition (Nd-based is Nd, Fe, B, etc.; Sm-based is Sm, C)
o, Fe, Co, etc. and Ce type are Ce, Co,
(Fe, Co, etc.) are melted in an inert gas using a high frequency melting furnace to create a magnet ingot. This ingot is coarsely crushed with a coarse crusher (shaw crusher or brown mill), and then with a jet mill in nitrogen with an average particle size of 3 μm.
Finely grind to m. This fine powder is oriented in a magnetic field, 1.
Compression molding is performed at a press pressure of 2 t/cm". This molded body is heated in a sintering furnace in a vacuum of 10-'Torr to 1090°C for Nd-based products, 1180°C for Sm-based products, and 10% for Ce-based products.
Sintering is performed at 70° C. for 1 hour, and the sintered body is subjected to an aging treatment to become a magnet. Finally, demagnetization adjustment is performed to produce the product.
次ぎに、本発明の具体的態様を実施例と比較例を挙げて
説明するが、本発明は、これら実施例に限定されるもの
ではない。Next, specific aspects of the present invention will be explained with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
（実施例１）
［Ｎｄ系希土類永久磁石］
粉末冶金法で製造したＮｄ系希土類永久硼石Ｎｄ＋ｓＦ
＋３ａ＋Ｂａを磁気回路に組み込みパルス着磁器を用い
てピーク磁場３０ｋＯｅでフル＠磁し、第１図すに示し
た減衰交流波形でフル着磁の８０％の大きさの磁界に減
磁調整した。この時の最初の波形の大きさからＩ／ｅの
大きさの波形に減少する時の時間である減衰定数では３
０ｍｓｅｃである。 減磁調整した磁石の磁界の安定性
を調べるため、減磁調整済磁石を１００，１２０、＋４
０、＋６０．１８０℃の各温度で夫々３０分間熱処理を
施し、熱処理前後での磁界の変化を第３図に示した。［
ここに
磁界の変化率（％）＝（１−（熱処理後の磁界／熱処理
前の磁界）Ｘ１００）で示す。］第３図から熱的に弱い
Ｎｄ系希土類永久磁石であるにも拘らず１４０℃付近ま
で熱処理による減磁がなく、耐熱性が安定しているのが
解る。(Example 1) [Nd-based rare earth permanent magnet] Nd-based rare earth permanent borate Nd+sF manufactured by powder metallurgy method
+3a+Ba was incorporated into the magnetic circuit and fully magnetized with a peak magnetic field of 30 kOe using a pulse magnetizer, and demagnetized to a magnetic field of 80% of the full magnetization using the attenuated AC waveform shown in FIG. At this time, the attenuation constant, which is the time when the initial waveform size decreases to the waveform size of I/e, is 3.
It is 0 msec. In order to investigate the stability of the magnetic field of the demagnetized magnet, the demagnetized magnet was 100, 120, +4
Heat treatment was performed at each temperature of 0 and +60.180°C for 30 minutes, and the changes in the magnetic field before and after the heat treatment are shown in Figure 3. [
Here, the rate of change of the magnetic field (%) is shown as (1-(magnetic field after heat treatment/magnetic field before heat treatment)X100). ] From FIG. 3, it can be seen that despite being a thermally weak Nd-based rare earth permanent magnet, there is no demagnetization due to heat treatment up to around 140° C., and the heat resistance is stable.
（実施例２）
［Ｓｍ系２−１７希土類磁石］
Ｎｄ系希土類永久磁石をＳｍ系２−１７希土類磁石Ｓｍ
（ＣＯｏ、 ｔＪｅｏ、 ２Ｃｕｏ、 ｏｓＺｒｏ、
０２） ７． Ｓとし・フル着磁の５０％の大きさの
磁界まで減磁調整した以外は実施例１と同様の条件で減
磁し、実施例１と同様に減磁調整済磁石の熱処理前後で
の磁界の変化を測定し、その結果を第４図に示した。紬
糸２−１７希土類磁石はＮｄ系希土類永久磁石に比較し
て熱的に安定なため、実施例１より熱処理後の減磁が少
なくなっている。(Example 2) [Sm-based 2-17 rare earth magnet] Nd-based rare earth permanent magnet was replaced with Sm-based 2-17 rare earth magnet Sm
(COo, tJeo, 2Cuo, osZro,
02) 7. Demagnetization was performed under the same conditions as in Example 1, except that the magnetic field was adjusted to 50% of the magnetic field of full magnetization. The changes were measured and the results are shown in Figure 4. Since the pongee yarn 2-17 rare earth magnet is thermally stable compared to the Nd-based rare earth permanent magnet, demagnetization after heat treatment is less than in Example 1.
（実施例３）
［Ｓｍ−Ｃｅ系希土類磁石］
Ｎｄ系希土類永久磁石を釦−Ｃｅ系希土類磁石釦ｏ、
５Ｃｅｏ、 ７ （Ｃｏｏ、 ７！ｐｅａ、 ＋５Ｃｕ
ｏ、 ＋ｚ）ｓ、 ａとし、フル着磁の５０％の大きさ
の磁界まで減磁調整した以外は実施例１と同様の条件で
減磁し、実施例１と同様に減磁調整済磁石の熱処理前後
での磁界の変化を測定し、その結果を第５図に示した。(Example 3) [Sm-Ce based rare earth magnet] Nd based rare earth permanent magnet button - Ce based rare earth magnet button o,
5Ceo, 7 (Coo, 7!pea, +5Cu
o, +z)s, a, and demagnetized under the same conditions as Example 1 except that the demagnetization was adjusted to a magnetic field that is 50% of the full magnetization, and the demagnetization adjusted magnet was The changes in the magnetic field before and after the heat treatment were measured, and the results are shown in FIG.
実施例２と同様に１４０℃までは減磁がなく、耐熱性が
安定していることが解る。As in Example 2, there was no demagnetization up to 140° C., indicating that the heat resistance was stable.
（実施例４）
［Ｓｍ系２−１７希土類磁石コ
Ｓｍ系２−１７希土類磁石Ｓｍ （Ｃｏｏ、 ｔＪｅｏ
、 ｚｃｕｏ、 ｏｓＺｒ。、。２）７６を円筒状に加
工し、コイル中引抜法により磁石の磁束を測定した。円
筒状に加工した磁石をパルス着磁器を使用してフル着磁
の５０％の大きさの磁界まで減磁調整した以外は実施例
１と同様の条件で減磁し、実施例１と同様に減磁調整済
磁石の熱処理前後での磁界の変化を測定し、その結果を
第６図に示した。磁束測定方法が変わっても磁界の変化
率に変化のないことが解る。(Example 4) [Sm-based 2-17 rare earth magnet Sm-based 2-17 rare earth magnet Sm (Coo, tJeo
, zcuo, osZr. ,. 2) 76 was processed into a cylindrical shape, and the magnetic flux of the magnet was measured by the coil drawing method. The cylindrical magnet was demagnetized under the same conditions as in Example 1, except that the magnet was demagnetized using a pulse magnetizer to a magnetic field that was 50% of the full magnetization. Changes in the magnetic field of the demagnetized magnet before and after heat treatment were measured, and the results are shown in FIG. It can be seen that the rate of change of the magnetic field does not change even if the magnetic flux measurement method changes.
（実施例５） ［Ｃｅ系希土類磁石］ Ｎｄ系希土類永久磁石をＣｅ系希土類磁石Ｃｅ （Ｃ。(Example 5) [Ce-based rare earth magnet] Nd-based rare earth permanent magnets are replaced by Ce-based rare earth magnets (Ce).
ａ、５ｔＦ８ａ、 ＋５ＣＬＩｏ、 ｚＮｉｏ、 ＋６
）ｓとし、フル着磁の５０％の大きさの磁界まで減磁調
整し、交流波形の減衰定数℃を１０〜２００ｍｓｅｃま
で変化させた以外は実施例１と同様の条件で減磁し、第
７図に横軸に減磁調整時の減衰定数でを、縦軸に１６０
’ｃｘ３０分間熱処理を掛けた時の磁気回路の磁界の変
化率を示した。減衰定数でか長くなる程熱的に安定化し
ていることが解る。a, 5tF8a, +5CLIo, zNio, +6
)s, demagnetization was adjusted to a magnetic field of 50% of the full magnetization, and demagnetization was performed under the same conditions as in Example 1, except that the attenuation constant of the AC waveform was varied from 10 to 200 msec. In Figure 7, the horizontal axis shows the attenuation constant during demagnetization adjustment, and the vertical axis shows 160
'cx' shows the rate of change in the magnetic field of the magnetic circuit when heat treatment is applied for 30 minutes. It can be seen that the longer the attenuation constant, the more thermally stable it becomes.
（比較例１）
実施例５のＣｅ系希土類磁石Ｃｅ（Ｃｏｏ、 １１７Ｆ
ｅｏ、 ＋５Ｃｕｏ、 ｚＮｉｏ、 ｔａｇｓを第１図
ａに示したパルス幅約３ｍｓｅｃのパルス波でフル着磁
の５０％の大きさの磁界まで減磁調整した以外は実施例
１と同様の条件で減磁し、実施例１と同様に減磁調整済
磁石の熱処理前後での磁界の変化を測定し、その結果を
第５図すに示した。パルス波による減磁調整は減衰交流
波と比較して磁界の変化率が大幅に増加し熱的に不安定
になることが解る。(Comparative Example 1) Ce-based rare earth magnet Ce (Coo, 117F) of Example 5
eo, +5Cuo, zNio, and tags were demagnetized under the same conditions as in Example 1, except that the demagnetization was adjusted to a magnetic field of 50% of the full magnetization using a pulse wave with a pulse width of about 3 msec shown in Figure 1a. The changes in the magnetic field before and after the heat treatment of the demagnetized magnet were measured in the same manner as in Example 1, and the results are shown in FIG. It can be seen that demagnetization adjustment using pulse waves significantly increases the rate of change of the magnetic field and becomes thermally unstable compared to damped AC waves.
（比較例２）
実施例２のＳｍ系２−１７希土類磁石釦（Ｃｏｏ、 ｔ
Ｊｅｏ、 ２Ｃｕｏ、 ｏｓＺｒ ０．０２１ ？、
６を静磁場を使用し、フル着磁の５０％の大きさの磁界
まで減磁調整した以外は実施例１と同様の条件で減磁し
、実施例１と同様に熱処理前後での磁界の変化を測定し
た。その結果を第５図Ｃに示した。静磁場による減磁調
整は減衰交流波と比較して磁界の変化率が大幅に増加し
熱的に不安定になることが解る。(Comparative Example 2) Sm-based 2-17 rare earth magnet button of Example 2 (Coo, t
Jeo, 2Cuo, osZr 0.021? ,
6 was demagnetized using a static magnetic field under the same conditions as in Example 1, except that the demagnetization was adjusted to a magnetic field of 50% of the full magnetization. Changes were measured. The results are shown in FIG. 5C. It can be seen that demagnetization adjustment using a static magnetic field significantly increases the rate of change of the magnetic field and becomes thermally unstable compared to damped alternating current waves.
（発明の効果）
本発明によれば、希土類永久磁石の減磁調整後の品質が
従来法と比較して、フラックスの熱的および磁場に対す
る安定性が大幅に向上し、磁気回路のギャップフラック
スを容易に調整することができ、産業上きわめて高い利
用価値を有する。(Effects of the Invention) According to the present invention, the quality of the rare earth permanent magnet after demagnetization adjustment is significantly improved compared to the conventional method, and the stability of the flux against thermal and magnetic fields is significantly improved, and the gap flux of the magnetic circuit is improved. It can be easily adjusted and has extremely high utility value in industry.
第１図にパルス波と減衰交流波の波形、第２図に磁壁の
位置とポテンシャルエネルギーの関係を示す。第３図〜
第６図には熱処理前後での磁界の変化率を実施例１〜５
および比較例１．２について示す、第７図は実施例５に
ついて減衰率と減磁率の関係を示す。
（ａ）パルス５座
（ｂ）５舐衰交須汲
臘１ｒのイＬｉ
第２図
第１図
第
図
第
図Figure 1 shows the waveforms of the pulse wave and the attenuated AC wave, and Figure 2 shows the relationship between the position of the domain wall and potential energy. Figure 3~
Figure 6 shows the rate of change in magnetic field before and after heat treatment for Examples 1 to 5.
FIG. 7, which is shown for Comparative Example 1.2, shows the relationship between the attenuation rate and the demagnetization rate for Example 5. (a) 5 pulses (b) 5 strokes 1r Li Li Figure 2 Figure 1 Figure Figure
Claims (3)
する希土類永久磁石の減磁方法。1. A method for demagnetizing rare earth permanent magnets, which comprises demagnetizing rare earth permanent magnets using an alternating current magnetic field.
磁石の減磁方法。2. 2. The method of demagnetizing a rare earth permanent magnet according to claim 1, wherein the alternating current magnetic field is of a damping type.
る請求項２記載の減衰型交流磁場。3. The attenuated alternating current magnetic field according to claim 2, wherein the attenuation constant is 5 msec or more and 500 msec or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30199988A JPH02148704A (en) | 1988-11-29 | 1988-11-29 | Method of demagnetizing rare-earth permanent magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30199988A JPH02148704A (en) | 1988-11-29 | 1988-11-29 | Method of demagnetizing rare-earth permanent magnet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02148704A true JPH02148704A (en) | 1990-06-07 |
Family
ID=17903665
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30199988A Pending JPH02148704A (en) | 1988-11-29 | 1988-11-29 | Method of demagnetizing rare-earth permanent magnet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02148704A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008135766A (en) * | 2002-02-15 | 2008-06-12 | Hitachi Metals Ltd | Magnetic field generator, and method for manufacturing same |
| JP2009291070A (en) * | 2009-09-08 | 2009-12-10 | Mitsubishi Electric Corp | Demagnetization device, device for decomposing product having permanent magnet, demagnetization method, and method of decomposing product having permanent magnet |
| US8322024B2 (en) | 2002-02-15 | 2012-12-04 | Hitachi Metals, Ltd. | Magnetic field generator manufacturing method |
-
1988
- 1988-11-29 JP JP30199988A patent/JPH02148704A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008135766A (en) * | 2002-02-15 | 2008-06-12 | Hitachi Metals Ltd | Magnetic field generator, and method for manufacturing same |
| JP4586850B2 (en) * | 2002-02-15 | 2010-11-24 | 日立金属株式会社 | Method for manufacturing magnetic field generator |
| US8322024B2 (en) | 2002-02-15 | 2012-12-04 | Hitachi Metals, Ltd. | Magnetic field generator manufacturing method |
| JP2009291070A (en) * | 2009-09-08 | 2009-12-10 | Mitsubishi Electric Corp | Demagnetization device, device for decomposing product having permanent magnet, demagnetization method, and method of decomposing product having permanent magnet |
| JP4666097B2 (en) * | 2009-09-08 | 2011-04-06 | 三菱電機株式会社 | Dismantling apparatus and disassembling method for products having permanent magnets |
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