JPH0684264B2 - Method for producing anisotropic oxide permanent magnet - Google Patents
Method for producing anisotropic oxide permanent magnetInfo
- Publication number
- JPH0684264B2 JPH0684264B2 JP60100512A JP10051285A JPH0684264B2 JP H0684264 B2 JPH0684264 B2 JP H0684264B2 JP 60100512 A JP60100512 A JP 60100512A JP 10051285 A JP10051285 A JP 10051285A JP H0684264 B2 JPH0684264 B2 JP H0684264B2
- Authority
- JP
- Japan
- Prior art keywords
- powder
- magnet
- magnetic field
- permanent magnet
- molding
- 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.)
- Expired - Lifetime
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- Hard Magnetic Materials (AREA)
- Magnetic Ceramics (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は酸化物永久磁石の製造方法に関し，特に湿式磁
界中成形に用いるフェライト磁石粉末の潤滑剤及び結着
性潤滑剤に関するものである。Description: TECHNICAL FIELD The present invention relates to a method for producing an oxide permanent magnet, and more particularly to a lubricant for ferrite magnet powder used in wet magnetic field molding and a binding lubricant.
磁界中で，マグネトプランバイト構造を有するフェライ
ト磁石微粉末を配向させた異方性磁石の製造方法とし
て，乾式法と湿式法の二通りが知られている。乾式法
は、フェライト磁石微粉末に結着剤としてポリビニルア
ルコール，酢酸ビニル，しょうのう，でん粉，パラフィ
ンワックス等を混合し，乾燥した粉末を磁界中で加圧成
形するものである。この方法は湿式法に比較して成形所
要時間が短く，装置が小さくてすみ，また複雑な形状の
成形にも適している等の長所を有している。しかし，乾
式磁場成形法においては，湿式法に比較してフェライト
粉末の配向性は低く，したがって磁石の性能が低くなる
という欠点も有している。また，フェライト磁石粉末
（一般には２μｍ以下）は成形性が悪いという欠点も合
わせて考慮しなければならない。There are two known methods for producing anisotropic magnets, in which ferrite magnet fine powder having a magnetoplumbite structure is oriented in a magnetic field, a dry method and a wet method. In the dry method, a fine powder of ferrite magnet is mixed with polyvinyl alcohol, vinyl acetate, camphor, starch, paraffin wax and the like as a binder, and the dried powder is pressure-molded in a magnetic field. Compared with the wet method, this method has the advantages that the time required for molding is shorter, the equipment is smaller, and it is also suitable for molding of complicated shapes. However, the dry magnetic field molding method has a disadvantage that the orientation of the ferrite powder is lower than that of the wet method, and therefore the performance of the magnet is reduced. In addition, it is necessary to take into consideration the disadvantage that the ferrite magnet powder (generally 2 μm or less) has poor formability.
一方湿式法は，フェライト磁石微粉末に分散剤として
水，ポリビニルアルコール水溶液，アルコール等を加
え，懸濁させ，金型中で磁界中にて粉末粒子を整列し，
成形するものである。この方法は，成形加圧中に分散媒
を金型外に排出する必要があり，このため成形に要する
時間が長くなる。強制的排液により成形時間の短縮を計
ると，成形装置が乾式法に比べ大がかりなものとなる。
また，成形圧力を大きくすると，成形体に亀裂がはいり
易く，複雑な形状の成形体が得難い等の欠点を有してい
る。しかしながら湿式磁場成形法では，乾式法では得ら
れないような高い性能の異方性フェライト磁石が製造で
きる。On the other hand, in the wet method, water, polyvinyl alcohol aqueous solution, alcohol, etc. are added as a dispersant to ferrite magnet fine powder and suspended, and the powder particles are aligned in a magnetic field in a mold,
It is what is molded. In this method, it is necessary to discharge the dispersion medium out of the mold during pressurization of the molding, which increases the time required for molding. If the molding time is shortened by forced drainage, the molding equipment will be larger than the dry method.
Further, when the molding pressure is increased, cracks are easily formed in the molded product, and it is difficult to obtain a molded product having a complicated shape. However, the wet magnetic field molding method can produce anisotropic ferrite magnets with high performance that cannot be obtained by the dry method.
上に説明したように，従来フェライト磁石粉末の成形性
と磁石特性の一要因となる磁場配向性は相反する傾向を
示している。As explained above, the moldability of conventional ferrite magnet powder and the magnetic field orientation, which is a factor in magnet characteristics, tend to contradict each other.
したがって本発明の目的は，前述の高い磁石特性の得ら
れる湿式法において，同時に成形性にも優れている酸化
物永久磁石の製造方法を得ようとするものである。Therefore, an object of the present invention is to obtain a method for producing an oxide permanent magnet which is excellent in formability at the same time in the above-mentioned wet method in which high magnet characteristics are obtained.
上記の目的を達成するためには磁石粉末の潤滑剤や結着
性潤滑剤の改良が重要と考え種々の実験を行った。その
結果一般に成形温度で固体となっているカプリン酸（C
10H21COOH）以上の分子量を有する飽和脂肪酸をフェラ
イト磁石粉炭の表面被覆剤として使用すると，磁石の高
性能化に非常に有益であるばかりでなく，粉末の成形性
の改善（湿式法における圧粉体強度の向上，圧粉体形状
の多様化等）にも効果のあることがわかった。また，カ
プリル酸（C8H17COOH）以下の分子量からカプロン酸（C
6H13COOH）までを磁石粉末の被覆に使用した場合は，結
着性の効果は見られないが，潤滑効果による配向性の向
上が実現されることが判明した。In order to achieve the above object, various experiments were conducted because it is important to improve the lubricant of the magnetic powder and the binding lubricant. As a result, capric acid (C
The use of saturated fatty acids having a molecular weight of 10 H 21 COOH) or more as a surface coating for ferrite magnet powder coal is not only very useful for improving the performance of the magnet, but also improves the powder formability (pressure in the wet method). It was also found to be effective in improving powder strength and diversifying green compact shapes. In addition, caproic acid (C 8 H 17 COOH) and caproic acid (C 8 H 17 COOH)
It was found that when up to 6 H 13 COOH) was used for coating the magnet powder, the binding effect was not observed, but the orientation effect was improved by the lubrication effect.
すなわち本発明は，フェライト磁石粉末の潤滑剤及び結
着性潤滑剤としてC6H13COOH以上の分子量を有する飽和
脂肪酸を磁石粉末に被覆混合することにより，湿式磁場
成形法でより高性能な異方性酸化物磁石の製造を可能に
するものである。また，飽和脂肪酸の分子量としては，
一般的な工業製品として生産されるベヘニン酸（C22H45
COOH）を実用的な上限値とした。That is, according to the present invention, as a lubricant for a ferrite magnet powder and a binding lubricant, a saturated fatty acid having a molecular weight of C 6 H 13 COOH or more is coated and mixed with the magnet powder to achieve a higher performance in wet magnetic field molding. This makes it possible to manufacture an anisotropic oxide magnet. In addition, as the molecular weight of saturated fatty acids,
Behenic acid (C 22 H 45
COOH) was set as a practical upper limit.
以下に実施例により本発明につき詳細に説明する。 The present invention will be described in detail below with reference to examples.
実施例１ 炭酸ストロンチウム（SrCO3）と酸化第２鉄（Fe2O3）を
モル比で1:5.8の割合で混合し,1250℃で２時間仮焼成
し，ボールミルで約0.8μｍの平均粒子径に微粉砕し
た。この粉末を乾燥し，実験用粉末とした。Example 1 Strontium carbonate (SrCO 3 ) and ferric oxide (Fe 2 O 3 ) were mixed at a molar ratio of 1: 5.8, calcined at 1250 ° C. for 2 hours, and average particle size of about 0.8 μm was measured with a ball mill. Finely ground to a diameter. This powder was dried and used as an experimental powder.
上記粉末に，磁石粉末に対しCnH2n+1COOH（ここでｎ＝
6,8,10,12,14,16,18,22）が1.5wt％になるように調合し
たトルエン溶液を混合し，乾燥した。この飽和脂肪酸を
被覆混合した粉末を，アルキルエーテル系非イオン界面
活性剤を0.3wt％溶解した水溶液を分散媒として，ボー
ルミルにて２分間解砕した。CnH 2 n +1 COOH (where n =
6,8,10,12,14,16,18,22) was mixed with a toluene solution prepared to be 1.5 wt% and dried. The powder obtained by coating and mixing the saturated fatty acid was crushed for 2 minutes by a ball mill using an aqueous solution in which 0.3 wt% of an alkyl ether nonionic surfactant was dissolved as a dispersion medium.
この泥漿を約10kOeの磁界中で直径20mm,高さ10mmの円盤
状に，試料圧0.3ton/cm2で成形した後,1210℃で１時間
本焼成を行ない磁気特性について調べた。The slurry was molded into a disk with a diameter of 20 mm and a height of 10 mm at a sample pressure of 0.3 ton / cm 2 in a magnetic field of about 10 kOe, and then subjected to main firing at 1210 ° C for 1 hour to examine the magnetic properties.
その結果を第２図に示す。CnH2n+1COOHでｎ＝６〜22の
分子量を有する飽和脂肪酸で磁石粉末を被覆混合するこ
とにより，高い（BH）maxが得られている。（BH）maxの
向上はBrの向上による寄与が大きく,Brの向上は磁石の
結晶粒のＣ面配向度の向上に対応していた。The results are shown in FIG. A high (BH) max has been obtained by coating and mixing magnet powder with saturated fatty acids having a molecular weight of n = 6-22 with CnH 2 n +1 COOH. The improvement of (BH) max was largely due to the improvement of Br, and the improvement of Br corresponded to the improvement of the C-plane orientation degree of the magnet crystal grains.
実施例２ 実施例１で作製した実験用ストロンチウムフェライト磁
石粉末に，ミリスチン酸（C14H29COOH）を０〜6wt％添
加し，約80℃にて混合した後冷却した。このミリスチン
酸を被覆混合した磁石粉末を，ボールミルにて70％アル
コール水溶液を分散媒として２分間解砕した。Example 2 0 to 6 wt% of myristic acid (C 14 H 29 COOH) was added to the experimental strontium ferrite magnet powder prepared in Example 1, mixed at about 80 ° C., and then cooled. The magnetic powder coated with myristic acid was crushed in a ball mill for 2 minutes using a 70% aqueous alcohol solution as a dispersion medium.
この泥漿を実施例１と同様にして磁場中成形した後,122
0℃で１時間本焼成を行ない，磁気特性について調べ
た。After molding this slurry in a magnetic field in the same manner as in Example 1, 122
Main firing was performed at 0 ° C. for 1 hour, and the magnetic properties were investigated.
その結果を第２図に示す。ミリスチン酸の被覆混合量が
０〜5wt％（０を含まず）で無被覆の粉末よりも高いエ
ネルギー積の磁石が得られている。（BH）maxの増加は,
Brの向上に対応しており,Brの向上は磁石の結晶粒子の
配向性の向上に対応している。また，ミリスチン酸の被
覆混合量増加にともなうBr,BHCの低下は，磁石中に残存
する脂肪酸より分解した炭素量に関係している。The results are shown in FIG. Magnets having a coating amount of myristic acid of 0 to 5 wt% (not including 0) and having a higher energy product than uncoated powder are obtained. The increase of (BH) max is
It corresponds to the improvement of Br, and the improvement of Br corresponds to the improvement of the orientation of the crystal grains of the magnet. A decrease in the coating mixture weight increases associated Br, B H C myristate is related to the amount of carbon to decompose from fatty acids remaining in the magnet.
以上実施例１と実施例２で明らかなように，ストロンチ
ウム微粉末にCnH2n+1COOH（ここでｎ＝６〜22）からな
る飽和脂肪酸の１種または２種以上を０〜5wt％（０を
含まず）被覆混合し，これを液中に分散させた泥漿を磁
界中で加圧成形することによって，異方性が高く，高性
能の酸化物永久磁石を製造することができる。As is clear from Examples 1 and 2, one or more saturated fatty acids composed of CnH 2 n +1 COOH (where n = 6 to 22) are added to strontium fine powder in an amount of 0 to 5 wt% ( It is possible to manufacture a high-performance oxide permanent magnet having high anisotropy by coating and mixing the slurry (not containing 0) and press-molding slurry dispersed in a liquid in a magnetic field.
なお上記の実施例においては，脂肪酸を被覆混合した粉
末を液中に分散させる方法として，分散媒としてアルコ
ール水溶液とアルキルエーテル系非イオン界面活性剤の
水溶液の使用についてのみ述べているが，粉末の分散性
を低下しないものであれば特に限定されるものではな
い。本実施例では，飽和脂肪酸の撥水性を低下させるた
めの界面活性剤の使用と，表面張力の小さいアルコール
水溶液による分散を行なったものである。In the above examples, as a method of dispersing powder mixed with fatty acids in a liquid, only the use of an aqueous alcohol solution and an aqueous solution of an alkyl ether nonionic surfactant as a dispersion medium is described. There is no particular limitation as long as the dispersibility is not reduced. In this example, the use of a surfactant for reducing the water repellency of saturated fatty acids and the dispersion with an aqueous alcohol solution having a small surface tension were carried out.
又上記実施例ではストロンチウムフェライト磁石につい
てのみ述べたが，本発明は，フェライト磁石の磁界中配
向性の向上に関する潤滑剤および結着性潤滑剤の効果に
おいて実現されるものであるから，これのみに限定され
ることなく，同系統の磁石材料であるバリウム，ストロ
ンチウム，カルシウム，鉛等の１種又は２種以上を含む
マグネトプランバイト型異方性磁石についても適用でき
るものである。Although only the strontium ferrite magnet is described in the above embodiment, the present invention is realized by the effect of the lubricant and the binding lubricant for improving the orientation of the ferrite magnet in the magnetic field. Without being limited, it is also applicable to a magnetoplumbite-type anisotropic magnet containing one or more of barium, strontium, calcium, lead and the like, which are magnet materials of the same system.
第１図は実施例１におけるストロンチウム磁石粉末に対
して被覆混合した飽和脂肪酸の種類と磁石特性の関係を
示し，第２図は実施例２におけるストロンチウム粉末に
対するミリスチン酸の被覆混合量と磁石特性の関係を示
す。FIG. 1 shows the relationship between the type of saturated fatty acid coated and mixed with the strontium magnet powder in Example 1 and the magnetic properties, and FIG. 2 shows the coating mixture amount of myristic acid with respect to the strontium powder and the magnetic properties in Example 2. Show the relationship.
Claims (1)
として化学式CnH2n+1COOH（ここでｎ＝６〜22）からな
る飽和脂肪酸の１種または２種以上を０〜5wt％（０を
含まず。）被覆混合し，これを液中に分散させた泥漿を
磁界中で加圧成形後，焼成することを特徴とする異方性
酸化物磁石の製造方法。1. 0 to 5 wt% of one or more saturated fatty acids having a chemical formula of CnH 2 n +1 COOH (where n = 6 to 22) as a lubricant and a binding lubricant in oxide magnet powder. % (Not including 0.) coating and mixing, and a slurry obtained by dispersing this in a liquid is pressure-molded in a magnetic field, followed by firing, and a method for producing an anisotropic oxide magnet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60100512A JPH0684264B2 (en) | 1985-05-14 | 1985-05-14 | Method for producing anisotropic oxide permanent magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60100512A JPH0684264B2 (en) | 1985-05-14 | 1985-05-14 | Method for producing anisotropic oxide permanent magnet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61261262A JPS61261262A (en) | 1986-11-19 |
| JPH0684264B2 true JPH0684264B2 (en) | 1994-10-26 |
Family
ID=14276000
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60100512A Expired - Lifetime JPH0684264B2 (en) | 1985-05-14 | 1985-05-14 | Method for producing anisotropic oxide permanent magnet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0684264B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5648039A (en) * | 1992-04-24 | 1997-07-15 | Tdk Corporation | Process for the production of anisotropic ferrite magnets |
| US5945028A (en) * | 1992-04-24 | 1999-08-31 | Tdk Corporation | Hexagonal system ferrite particles and their production process |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5319118B2 (en) * | 1972-03-23 | 1978-06-19 | ||
| JPS6054964A (en) * | 1983-09-07 | 1985-03-29 | 日立化成工業株式会社 | Manufacture of ceramic mud |
-
1985
- 1985-05-14 JP JP60100512A patent/JPH0684264B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61261262A (en) | 1986-11-19 |
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