JPS6312134B2 - - Google Patents
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- Publication number
- JPS6312134B2 JPS6312134B2 JP59026971A JP2697184A JPS6312134B2 JP S6312134 B2 JPS6312134 B2 JP S6312134B2 JP 59026971 A JP59026971 A JP 59026971A JP 2697184 A JP2697184 A JP 2697184A JP S6312134 B2 JPS6312134 B2 JP S6312134B2
- Authority
- JP
- Japan
- Prior art keywords
- alloy powder
- rco
- oxygen content
- water
- magnet
- 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
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- 239000000843 powder Substances 0.000 claims description 47
- 229910045601 alloy Inorganic materials 0.000 claims description 31
- 239000000956 alloy Substances 0.000 claims description 31
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 28
- 239000001301 oxygen Substances 0.000 claims description 28
- 229910052760 oxygen Inorganic materials 0.000 claims description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 11
- 150000002910 rare earth metals Chemical class 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 10
- 229910017052 cobalt Inorganic materials 0.000 claims description 9
- 239000010941 cobalt Substances 0.000 claims description 9
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 9
- 239000003960 organic solvent Substances 0.000 claims description 7
- 238000005245 sintering Methods 0.000 claims description 4
- 239000012298 atmosphere Substances 0.000 claims description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 42
- 238000000034 method Methods 0.000 description 8
- 229910000531 Co alloy Inorganic materials 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 229910052777 Praseodymium Inorganic materials 0.000 description 3
- 229910052772 Samarium Inorganic materials 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- 238000010793 Steam injection (oil industry) Methods 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000009423 ventilation Methods 0.000 description 2
- 239000012300 argon atmosphere Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- XOOUIPVCVHRTMJ-UHFFFAOYSA-L zinc stearate Chemical compound [Zn+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O XOOUIPVCVHRTMJ-UHFFFAOYSA-L 0.000 description 1
Landscapes
- Powder Metallurgy (AREA)
- Hard Magnetic Materials (AREA)
Description
本発明は、RCo5系コバルト合金粉末（但しＲ
は希土類金属）を原料として希土類コバルト磁石
を製造する方法に関し、更に詳細には、RCo5系
コバルト合金粉末の酸素含有量を予め適当に増大
調整したものを用いて保磁力等の磁気特性の増大
した希土類コバルト磁石を製造する方法に関す
る。
従来、此種磁石の製造法として、RCo5系コバ
ルト合金粉末を空気中で100℃程度に加熱して粉
末表面を酸化させたものを不活性雰囲気中で焼結
して製造することが提案されているが、粉末を加
熱する際に発火する危険性があり而も粉体の酸化
を均一に制御することが困難で工業化することが
できなかつた。
本発明は、かゝる欠点を解消し、RCo5系コバ
ルト合金粉末に所望の酸素含有量を円滑且つ均一
に増大せしめることを可能とし、かくして所定の
酸素量を含有したRCo5コバルト合金を用いて保
磁力等の磁気特性の増大した希土類コバルト磁石
を製造する方法を提供するものでRCo5系合金粉
末（但しＲは希土類金属）を磁場成形した後不活
性雰囲気中で焼結してなる希土類コバルト磁石の
製造法において、該RCo5系合金粉末として、予
め、これを微量の水を混入した有機溶剤中に浸漬
してその添加水分による経時的酸素を行ない酸素
含有量を調整したものを用いることを特徴とす
る。
次に本発明の実施例を説明する。
実施例 １
Sm25.0wt％、Pr9.5wt％、Co65.5wt％から成
る合金をジエツトミルでN2ガス雰囲気中で４〜
6μmに粉砕し、その合金粉末を、水を含まないト
ルエンを満たした容器中に密封浸漬保存しておい
たものに、使用に当り容器内に水を所定量添加
し、含水量2.0％に調整したトルエン中で300時間
密封浸漬状態に放置した。その後フイルター過
器を用いて粉末とトルエンを分離し、その粉末を
水分を実質上含まないトルエン（含水量0.05wt
％）に浸漬し、数分間撹拌した後、フイルター
過器により再び粉末とトルエンを分離し、表面に
付着の水分を含まないトルエンで湿潤し空気酸化
から保護された粉末を得た。次でこの粉末を温度
25℃、湿度60％以下で２時間通風し僅かに湿つて
いる程度まで乾燥した。その乾燥粉末の酸素含有
量は0.29wt％であつた。このように本法により予
め酸素含有量を調整した乾燥RCo5合金粉末にバ
インダー例えばステアリン酸亜鉛粉末を0.3wt％
加えてボールミルで１時間混練した後、
10.000Oeの磁場中で2t／cm2の圧力で加圧成形し、
直径10mm厚さ２mmの円板を製作した。更にこの円
板をアルゴン雰囲気中で1180℃、10分間保持した
後、１時間で100℃まで急冷し、焼結を終了した。
このようにして得た磁石の磁気特性は、下記第１
表の試料No.１に示す通りであつた。上記と同じ組
成のRCo5合金粉末を原料とし、トルエン中の水
分の含有量、及び浸漬時間を色々変えた以外は、
上記と同じ要領で夫々の磁石を製造した。その
夫々の磁気特性は第１表の試料No.２〜No.４に示す
通りであつた。比較のため、前記と同じ組成の
RCo5合金粉末を水を添加しないトルエン（含水
量0.05wt％）に夫々浸漬し、放置時間を500時間
及び70時間と変えて処理したものを、前記と仝様
に通風乾燥して得られた酸素含有量夫々0.23wt
％、0.21wt％を有する乾燥粉末につき、上記と同
じ条件で磁石を夫々作成し、その磁気特性を測定
した。その結果は試料No.５，No.６に示す通りであ
つた。
The present invention uses RCo 5 -based cobalt alloy powder (however, R
The method relates to a method for manufacturing a rare earth cobalt magnet using a rare earth metal (rare earth metal) as a raw material, and more specifically, it relates to a method of manufacturing a rare earth cobalt magnet using RCo 5 cobalt alloy powder whose oxygen content has been appropriately increased in advance to increase magnetic properties such as coercive force. The present invention relates to a method of manufacturing rare earth cobalt magnets. Conventionally, it has been proposed to manufacture this kind of magnet by heating RCo 5 cobalt alloy powder in air to about 100℃ to oxidize the powder surface, and then sintering it in an inert atmosphere. However, there was a risk of ignition when the powder was heated, and it was difficult to control the oxidation of the powder uniformly, making it impossible to commercialize it. The present invention eliminates such drawbacks and makes it possible to smoothly and uniformly increase the desired oxygen content in the RCo 5 cobalt alloy powder, and thus makes it possible to use the RCo 5 cobalt alloy containing a predetermined amount of oxygen. This method provides a method for producing rare earth cobalt magnets with increased magnetic properties such as coercive force. In the method for manufacturing cobalt magnets, the RCo 5 alloy powder is immersed in an organic solvent mixed with a small amount of water, and the oxygen content is adjusted by adding water over time to adjust the oxygen content. It is characterized by Next, examples of the present invention will be described. Example 1 An alloy consisting of 25.0 wt% Sm, 9.5 wt% Pr, and 65.5 wt% Co was processed in a N2 gas atmosphere using a jet mill for 4 to 40 minutes.
The alloy powder is ground to 6μm and stored in a container filled with water-free toluene in a sealed container, and before use, a predetermined amount of water is added to the container to adjust the water content to 2.0%. The sample was left immersed in sealed toluene for 300 hours. After that, the powder and toluene are separated using a filter, and the powder is converted into toluene containing substantially no water (moisture content: 0.05wt).
%) and stirred for a few minutes, the powder and toluene were separated again using a filter to obtain a powder moistened with toluene without moisture attached to the surface and protected from air oxidation. This powder at the following temperature
It was ventilated for 2 hours at 25°C and humidity below 60% to dry it until it was slightly damp. The oxygen content of the dry powder was 0.29wt%. In this way, a binder such as zinc stearate powder is added at 0.3 wt% to dry RCo 5 alloy powder whose oxygen content has been adjusted in advance by this method.
In addition, after kneading in a ball mill for 1 hour,
Pressure molded at a pressure of 2t/cm 2 in a magnetic field of 10.000Oe,
A disk with a diameter of 10 mm and a thickness of 2 mm was manufactured. Further, this disk was held at 1180°C for 10 minutes in an argon atmosphere, and then rapidly cooled to 100°C in 1 hour to complete the sintering.
The magnetic properties of the magnet thus obtained are as follows:
It was as shown in sample No. 1 in the table. The raw material was RCo 5 alloy powder with the same composition as above, except that the water content in toluene and the immersion time were varied.
Each magnet was manufactured in the same manner as above. The magnetic properties of each sample were as shown in Samples No. 2 to No. 4 in Table 1. For comparison, the same composition as above was used.
RCo 5 alloy powder was immersed in toluene (water content 0.05 wt%) without adding water, treated with different standing times of 500 hours and 70 hours, and then dried with ventilation in the same manner as above. Oxygen content 0.23wt each
% and 0.21 wt%, magnets were prepared under the same conditions as above, and their magnetic properties were measured. The results were as shown in Samples No. 5 and No. 6.
【表】
上記第１表から明らかなように、本法により得
られた磁石試料No.１〜No.４は、特に、その保磁力
及び最大エネルギー積において、酸素含有量の調
整を行なわないRCo5合金粉末を用いて製造した
磁石試料No.５，No.６に比し、著しく向上すること
が認められた。
尚、多くの試験研究の結果、RCo5系合金粉末
の酸素含有量の調整において、その酸素含有量を
0.3wt％及びその前後を有するものを得るには、
有機溶剤の水分含有量が2wt％未満の場合は500
時間以上の浸漬時間を要し製造上能率が低下する
傾向があり、１方6wt％を越える場合は、酸化が
急速に進行し、僅かな時間の差で酸化率が大きく
変化するので、酸素含有量の一定の調整が比較的
困難となる嫌いがあり、従つて有機溶剤中の水分
含有量は約２〜6wt％の範囲が作業性、経済性の
見地から好ましい。
調整粉末の酸素含有量は、0.32wt％を越えると
むしろ試料No.５，No.６と殆んど変らないか、それ
以下の磁気特性となることが認められた。従つて
酸素含有量は0.32wt％以下にとゞめることが有効
である。
本発明によれば、酸素含有量を0.29wt％〜
0.32wt％に調整されたRCo系合金粉末を100％用
いて磁石を製造する以外に、これと酸素含有量を
調整しないRCo系合金粉末とを配合し、その総合
した酸素含有量が0.29wt％〜0.32wt％の範囲に調
整した混合粉末としたものを用いても、磁気特性
の著しく向上した磁石が得られることが認められ
た。
次にその具体例を次に示す。
実施例 ２
上記表１の磁石試料No.４を作成するに当り用い
た酸素含有量を調整された合金粉末（酸素含有量
0.32wt％）を81.8ｇと表１の磁石試料No.６を作成
するに用いた酸素含有量を調整しない合金粉末
（酸素含有量0.21wt％）を18.2ｇとを混合し、総
合した酸素含有量が0.3wt％とした合金粉末を製
造し、これを用いて実施例１と同じ条件で成形、
焼結を行ない磁石を得た。その磁石の残留磁束密
度は10900G、保磁力は8000Oe、最大エネルギー
積は29.5MGOeであつた。
実施例 ３
実施例１と同じRCo5合金粉末を、含水量4.0wt
％のブチルアルコールに200時間浸漬し密封状態
で放置した後実施例１と仝様に処理して酸素含有
量0.32wt％の合金粉末を得た。この合金粉末72.7
ｇと、実施例１と同じ合金粉末を、水分を添加し
ない実質上水分を含まないトルエン（含水量
0.05wt％）に140時間浸漬した後トルエンと分離、
通風乾燥して得た酸素含有量0.22wt％の合金粉末
27.3ｇとを混合し総合した酸素含有量0.3wt％と
した合金粉末を用いて、実施例１と仝様に磁石を
製造した。その磁石の残留磁束密度は10800G、
保磁力は7800Oe、最大エネルギー積は
29.6MGOeであつた。
尚、比較のため、RCo5合金粉末を、水を含ま
ない有機溶媒に浸漬し、該溶媒中に水蒸気を吹込
んで酸化処理した場合の比較例を以下に記載す
る。
比較例 １
実施例１で用いたと同じ組成のSm・Pr・Coか
ら成る４〜6μmの合金粉末を、水を含まないトル
エンを満たした容器中に浸漬し、室温の状態で、
水蒸気を１容量％含む窒素ガスを、毎分１リツト
ルの流量で、５時間吹き込み続けた後、フイルタ
ー過器により、粉末とトルエンとを分離した事
以外は、実施例１と同様に行なつた。その結果を
下記第２表試料No.７に示した。
比較例 ２
実施例１で用いたと同じ組成のSm・Pr・Coか
ら成る４〜6μmの合金粉末を、水を含まないトル
エンを満たした容器中に浸漬し、50℃に保つたま
ま、水蒸気を１容量％含む窒素ガスを、毎分１リ
ツトルの流量で、５時間吹き込み続けた後、フイ
ルター過器により、粉末とトルエンとを分離し
た事以外は、実施例１と同様に行なつた。その結
果を第２表試料No.８に示した。[Table] As is clear from Table 1 above, magnet samples No. 1 to No. 4 obtained by this method are particularly good at coercive force and maximum energy product of RCo without oxygen content adjustment. It was recognized that this was significantly improved compared to magnet samples No. 5 and No. 6 manufactured using 5 alloy powder. In addition, as a result of many test studies, in adjusting the oxygen content of RCo 5 alloy powder, the oxygen content
To obtain 0.3wt% and around it,
500 if the water content of the organic solvent is less than 2wt%
Oxygen-containing Since it is relatively difficult to adjust the amount to a certain level, the water content in the organic solvent is preferably in the range of about 2 to 6 wt% from the viewpoint of workability and economy. It was found that when the oxygen content of the prepared powder exceeds 0.32 wt%, the magnetic properties become almost the same as those of Samples No. 5 and No. 6, or even lower. Therefore, it is effective to keep the oxygen content to 0.32wt% or less. According to the present invention, the oxygen content is 0.29wt%~
In addition to manufacturing magnets using 100% RCo alloy powder adjusted to 0.32wt%, we also blend this with RCo alloy powder whose oxygen content is not adjusted, and the total oxygen content is 0.29wt%. It was found that a magnet with significantly improved magnetic properties could be obtained even when a mixed powder adjusted to a range of ~0.32 wt% was used. Next, a specific example is shown below. Example 2 Alloy powder with adjusted oxygen content (oxygen content
0.32wt%) and 18.2g of the alloy powder (oxygen content 0.21wt%) used to create magnet sample No. 6 in Table 1, whose oxygen content was not adjusted, were mixed to obtain a total oxygen content. An alloy powder with an amount of 0.3 wt% was produced, and this was molded under the same conditions as in Example 1.
A magnet was obtained by sintering. The magnet had a residual magnetic flux density of 10,900G, a coercive force of 8,000Oe, and a maximum energy product of 29.5MGOe. Example 3 The same RCo 5 alloy powder as in Example 1 was used with a water content of 4.0wt.
% butyl alcohol for 200 hours, left in a sealed state, and then treated in the same manner as in Example 1 to obtain an alloy powder with an oxygen content of 0.32 wt %. This alloy powder 72.7
g and the same alloy powder as in Example 1 in substantially water-free toluene (water content:
0.05wt%) for 140 hours and then separated from toluene.
Alloy powder with oxygen content of 0.22wt% obtained by ventilation drying
A magnet was manufactured in the same manner as in Example 1 using an alloy powder mixed with 27.3 g of 27.3 g to give a total oxygen content of 0.3 wt%. The residual magnetic flux density of the magnet is 10800G,
Coercive force is 7800Oe, maximum energy product is
It was 29.6 MGOe. For comparison, a comparative example will be described below in which RCo 5 alloy powder was immersed in a water-free organic solvent and oxidized by blowing steam into the solvent. Comparative Example 1 An alloy powder of 4 to 6 μm consisting of Sm, Pr, and Co having the same composition as that used in Example 1 was immersed in a container filled with water-free toluene, and was heated at room temperature.
The process was carried out in the same manner as in Example 1, except that nitrogen gas containing 1% by volume of water vapor was continuously blown in at a flow rate of 1 liter per minute for 5 hours, and then the powder and toluene were separated using a filter. . The results are shown in Sample No. 7 in Table 2 below. Comparative Example 2 An alloy powder of 4 to 6 μm consisting of Sm, Pr, and Co having the same composition as used in Example 1 was immersed in a container filled with water-free toluene, and water vapor was removed while keeping the temperature at 50°C. The same procedure as in Example 1 was carried out, except that nitrogen gas containing 1% by volume was continuously blown at a flow rate of 1 liter per minute for 5 hours, and then the powder and toluene were separated using a filter. The results are shown in Sample No. 8 in Table 2.
【表】
上記表から明らかなように、RCo5合金粉末を
水蒸気吹き込みにより酸化せしめるときは、これ
を用いて製造した磁石の磁気特性は、第１表の試
料No.５，No.６の末処理RCo5合金粉末を用いて製
造した磁石の磁気特性と対比して保磁力Hcは僅
かに増加するものの、残留磁束密度Br及び最大
エネルギー積BHmax値は殆んど変らないどころ
かむしろ低下するので、RCo5合金粉末の磁気特
性の向上には、水蒸気吹き込み処理は磁石特性の
改善には効果がないことが分る。
このように本発明によるときは、希土類コバル
ト磁石の製造に当り、予めその原料であるRCo5
系合金粉末を一旦水分を微量に添加した有機溶剤
中に所要時間浸漬してその添加水分による経時的
な酸化即ち、緩徐な酸化を行ないその酸素含有量
の調整を行ない、これを用いて磁石を製造するの
で、かゝる事前処理を行なわないRCo5系合金粉
末を用いて製造した磁石或はRCo5系合金粉末を
水蒸気吹き込みにより酸化処理したものを用い製
造した磁石に比しその磁気特性を著しく向上した
希土類コバルト磁石を得ることが出来る効果をも
たらす。[Table] As is clear from the above table, when the RCo 5 alloy powder is oxidized by steam injection, the magnetic properties of the magnets manufactured using it are the same as those of samples No. 5 and No. 6 in Table 1. Although the coercive force Hc slightly increases compared to the magnetic properties of the magnet manufactured using the treated RCo 5 alloy powder, the residual magnetic flux density Br and the maximum energy product BHmax value do not change much, but rather decrease. It can be seen that steam blowing treatment is not effective in improving the magnetic properties of RCo 5 alloy powder. As described above, according to the present invention, when producing a rare earth cobalt magnet, RCo 5 which is the raw material is prepared in advance.
The alloy powder is immersed in an organic solvent to which a small amount of water has been added for a required period of time, and the added water oxidizes it over time, that is, slowly oxidizes it, adjusting its oxygen content. Since the magnets are manufactured using RCo 5 alloy powder without such pre-treatment, or the magnets manufactured using RCo 5 alloy powder that has been oxidized by steam injection, its magnetic properties are lower. This brings about the effect that a significantly improved rare earth cobalt magnet can be obtained.
Claims (1)
磁場成形した後不活性雰囲気中で焼結してなる希
土類コバルト磁石の製造法において、該RCo5系
合金粉末として、予め、これを微量の水を混入し
た有機溶剤中に浸漬してその添加水分による経時
的酸化を行ない酸素含有量を調整したものを用い
ることを特徴とする希土類コバルト磁石の製造
法。 ２ RCo5系合金粉末を水分２〜６重量％を含有
した有機溶剤中に40〜300時間浸漬して酸素含有
量を0.29重量％未満〜0.32重量％程度に予め調整
したものを用いることを特徴とする特許請求の範
囲１に記載の製造法。[Claims] 1. A method for producing a rare earth cobalt magnet by magnetically forming RCo 5 alloy powder (where R is a rare earth metal) and then sintering it in an inert atmosphere, as the RCo 5 alloy powder, A method for producing a rare earth cobalt magnet, characterized in that the magnet is immersed in an organic solvent mixed with a small amount of water and oxidized over time by the added water to adjust the oxygen content. 2 RCo 5 alloy powder is immersed in an organic solvent containing 2 to 6% water by weight for 40 to 300 hours to adjust the oxygen content to less than 0.29% by weight to about 0.32% by weight. The manufacturing method according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59026971A JPS60174839A (en) | 1984-02-17 | 1984-02-17 | Production of magnet consisting of rare earth cobalt |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59026971A JPS60174839A (en) | 1984-02-17 | 1984-02-17 | Production of magnet consisting of rare earth cobalt |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60174839A JPS60174839A (en) | 1985-09-09 |
| JPS6312134B2 true JPS6312134B2 (en) | 1988-03-17 |
Family
ID=12208039
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59026971A Granted JPS60174839A (en) | 1984-02-17 | 1984-02-17 | Production of magnet consisting of rare earth cobalt |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60174839A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6324030A (en) * | 1986-06-26 | 1988-02-01 | Res Dev Corp Of Japan | Anisotropic rare earth magnet material and its production |
| JPH02163443A (en) * | 1988-12-19 | 1990-06-22 | Toyota Motor Corp | Controller for engine equipped with supercharger |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53110920A (en) * | 1977-03-10 | 1978-09-28 | Namiki Precision Jewel Co Ltd | Method of making rare earth cobalt based permanent magnet alloy |
| JPS5413848A (en) * | 1977-07-04 | 1979-02-01 | Shibaura Eng Works Ltd | Muffler |
| JPS5785901A (en) * | 1980-11-14 | 1982-05-28 | Hitachi Ltd | Method for stabilization of metallic magnetic powder |
-
1984
- 1984-02-17 JP JP59026971A patent/JPS60174839A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53110920A (en) * | 1977-03-10 | 1978-09-28 | Namiki Precision Jewel Co Ltd | Method of making rare earth cobalt based permanent magnet alloy |
| JPS5413848A (en) * | 1977-07-04 | 1979-02-01 | Shibaura Eng Works Ltd | Muffler |
| JPS5785901A (en) * | 1980-11-14 | 1982-05-28 | Hitachi Ltd | Method for stabilization of metallic magnetic powder |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60174839A (en) | 1985-09-09 |
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