JPH0565511A - Production of superfine powder of cobalt - Google Patents
Production of superfine powder of cobaltInfo
- Publication number
- JPH0565511A JPH0565511A JP20640991A JP20640991A JPH0565511A JP H0565511 A JPH0565511 A JP H0565511A JP 20640991 A JP20640991 A JP 20640991A JP 20640991 A JP20640991 A JP 20640991A JP H0565511 A JPH0565511 A JP H0565511A
- Authority
- JP
- Japan
- Prior art keywords
- cobalt
- particle size
- surface area
- thermal decomposition
- specific surface
- 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
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、一次粒子径が 100 nm
以下と極めて小さいコバルト超微粉の製造法である。本
発明による金属超微粉は各種金属触媒材料、電磁波シー
ルド材料、電子回路素子材料、導電性塗料、磁気記録材
料や粉末冶金などの分野において好適に使用できるもの
である。The present invention has a primary particle size of 100 nm.
The following is a very small manufacturing method of cobalt ultrafine powder. The ultrafine metal powder according to the present invention can be suitably used in the fields of various metal catalyst materials, electromagnetic wave shielding materials, electronic circuit element materials, conductive paints, magnetic recording materials, powder metallurgy and the like.
【０００２】[0002]
【従来の技術】金属微粉の製造法としては、電解法、ア
トマイズ法、機械的粉砕などが知られ、主に粉末冶金な
どの用途に用いられている。これら方法による銅粉は、
粒子径が大きく、製造条件の制御や分別によってより微
細な銅粉も得られるように成ってきているが、生産性が
悪く、微細化にも自ずと限度があるものであった。最
近、粒子径が１〜100 nmの超微粒子或いは超微粉は、極
めて大きい比表面積と表面エネルギーを有する。このた
め、いわゆる微粉とは全く異なる挙動、特性を示す新素
材として注目されてきている。このような超微粉の製造
法としては、ガス中蒸発法、スパッタリング法、プラズ
マ蒸発法、ガスデポジション法などの物理的方法或いは
金属カルボニル化合物の熱分解法、金属塩化物の気相還
元法、金属塩溶液の沈殿法や電解法などが知られてい
る。2. Description of the Related Art As a method for producing fine metal powder, an electrolytic method, an atomizing method, mechanical pulverization and the like are known, and they are mainly used for applications such as powder metallurgy. Copper powder by these methods,
Although finer copper powders have a large particle size and can be obtained by controlling the production conditions and fractionation, the productivity is poor, and the miniaturization is naturally limited. Recently, ultrafine particles or ultrafine particles having a particle size of 1 to 100 nm have an extremely large specific surface area and surface energy. For this reason, it has been attracting attention as a new material that exhibits completely different behavior and characteristics from so-called fine powder. As a method for producing such ultrafine powder, a vaporization method in gas, a sputtering method, a plasma evaporation method, a physical method such as a gas deposition method or a thermal decomposition method of a metal carbonyl compound, a vapor phase reduction method of a metal chloride, Known methods include precipitation of metal salt solutions and electrolysis.
【０００３】これらの方法は大規模で高価な製造装置が
必要であったり、毒性が高く危険で取り扱いがたい出発
原料を用いたり、複雑な工程うが必要であったりするも
のであった。この為、簡便でかつ経済性の高い超微粒子
の製造法が求められていた。These methods require large-scale and expensive manufacturing equipment, use starting materials that are highly toxic, dangerous and difficult to handle, and require complicated steps. Therefore, a simple and economical method for producing ultrafine particles has been demanded.
【０００４】[0004]
【発明が解決しようとする課題】本発明者等は金属超微
粉の簡便でかつ経済的で工業的規模で実施可能な方法を
鋭意検討した結果、蟻酸コバルト又は蓚酸コバルトにパ
ラジウムを共存させて、熱分解する方法を見出し、本発
明を完成させた。DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of diligent studies by the present inventors on a method for producing ultrafine metal powder, which is simple and economical, and which can be carried out on an industrial scale, the presence of palladium in cobalt formate or cobalt oxalate, The method of thermal decomposition was found and the present invention was completed.
【０００５】[0005]
【課題を解決するための手段】すなわち、本発明は、蟻
酸コバルト又は蓚酸コバルトをパラジウムの共存下、非
酸化性雰囲気下又は減圧下、 400℃以下で熱分解し、一
次粒子径が 100 nm 以下、比表面積が10〜80m2/g、凝集
粒子径が 5,000nm以下であることを特徴とするコバルト
超微粉の製造法であり、該熱分解時の昇温速度が 0.5〜
20℃/minであること、該熱分解温度が 200〜360℃であ
るコバルト超微粉の製造法である。[Means for Solving the Problems] That is, the present invention is that cobalt formate or cobalt oxalate is thermally decomposed at 400 ° C. or lower in the presence of palladium, in a non-oxidizing atmosphere or under reduced pressure, and the primary particle diameter is 100 nm or less. , A specific surface area of 10 to 80 m 2 / g, an aggregate particle diameter of 5,000 nm or less is a method for producing ultrafine cobalt powder, the temperature rising rate during the thermal decomposition is 0.5 ~
It is a method for producing cobalt ultrafine powder having a thermal decomposition temperature of 200 to 360 ° C. at 20 ° C./min.
【０００６】以下、本発明について説明する。本発明の
蟻酸コバルト、蓚酸コバルトは、含水でも、無水或いは
脱水処理したものでもよい。また、単独でも混合物とし
ても使用可能である。このコバルト塩にパラジウムを共
存させることにより、熱分解温度を低下させてコバルト
超微粉を製造する。このパラジウムは、通常、パラジウ
ム塩の形で使用する。パラジウム塩としては、塩化パラ
ジウム、酢酸パラジウム、硝酸パラジウム、硫酸パラジ
ウムなどが挙げられ、ハロゲン、硫黄、その他の不純物
を残留させない面からは酢酸パラジウムなどの比較的低
温で分解する有機酸塩が好適である。The present invention will be described below. The cobalt formate and cobalt oxalate of the present invention may be hydrous, anhydrous or dehydrated. Further, they can be used alone or as a mixture. Coexistence of palladium in this cobalt salt lowers the thermal decomposition temperature to produce ultrafine cobalt powder. This palladium is usually used in the form of a palladium salt. Examples of the palladium salt include palladium chloride, palladium acetate, palladium nitrate, palladium sulfate, and the like. From the viewpoint of not leaving halogen, sulfur, and other impurities, an organic acid salt such as palladium acetate that decomposes at a relatively low temperature is preferable. is there.
【０００７】上記において、パラジウムを共存させる方
法としては、機械的に混合して分散或いは付着させる方
法、本発明の金属の酢酸塩の製造工程中にパラジウム塩
を添加し、結晶中にパラジウムが内包されたものとして
用いる方法が挙げられる。より少量のパラジウムでより
良好な熱分解特性、より微細なコバルト超微粉を得る面
から、結晶中にパラジウムを含有させるのが好ましく、
好適にはパラジウムを重量で 100〜6,000 ppm の範囲で
含むものが好ましい。In the above, as a method of coexisting palladium, a method of mechanically mixing and dispersing or adhering, a palladium salt is added during the process of producing the metal acetate of the present invention, and palladium is included in the crystal. The method used as the one described above is included. Better thermal decomposition characteristics with a smaller amount of palladium, from the viewpoint of obtaining finer cobalt ultrafine powder, it is preferable to include palladium in the crystal,
It is preferable that palladium is contained in the range of 100 to 6,000 ppm by weight.
【０００８】本発明の金属の酢酸塩の熱分解は、非酸化
性雰囲気中或いは減圧下に、昇温速度 0.5〜20℃/min
で、保持温度 400℃以下、好ましくは 230〜360 ℃の範
囲である。コバルト超微粉の一次粒子径、凝集粒子径
は、熱分解条件の影響を受ける。昇温速度が20℃/minを
超える場合、温度が 400℃を超える場合には、一次粒子
径、凝集粒子径ともに不揃いでより大きなもの、特に凝
集粒子径が 5,000nmを超えたものとなるので好ましくな
い。また、熱分解雰囲気は、得られる金属超微粉の粒子
径などに大きな影響を与えないので、操作が容易な常圧
付近の非酸化性雰囲気が好ましい。また減圧雰囲気の場
合、30mmHg以下、特に 5mmHg以下の圧力範囲を保つのが
好ましい。The thermal decomposition of the metal acetate of the present invention is carried out in a non-oxidizing atmosphere or under reduced pressure at a heating rate of 0.5 to 20 ° C./min.
The holding temperature is 400 ° C or lower, preferably 230 to 360 ° C. The primary particle size and agglomerated particle size of cobalt ultrafine powder are affected by the thermal decomposition conditions. If the heating rate exceeds 20 ° C / min, or if the temperature exceeds 400 ° C, the primary particle size and the aggregated particle size will be uneven and larger, especially the aggregated particle size will exceed 5,000 nm. Not preferable. Further, the thermal decomposition atmosphere does not have a great influence on the particle size of the obtained ultrafine metal powder or the like, and thus a non-oxidizing atmosphere near atmospheric pressure is preferable because it is easy to operate. In the case of a reduced pressure atmosphere, it is preferable to keep the pressure range of 30 mmHg or less, especially 5 mmHg or less.
【０００９】以上の方法による本発明のコバルト超微粉
は、SEM 観察によれば、通常、一次粒子径 100 nm 未満
(SEM=scanning electron micrographs ; 識別可能粒子
径の下限は約 10nm)、凝集粒子径 5000nm 未満で、比表
面積 6〜80m2/gの金属超微粉である。このコバルト超微
粉は、サブミクロンオーダー程度の金属微粉に比較して
極めて活性に富んだものである。従って、室温下におい
ても空気中では発火、燃焼する場合がある。このため、
空気中での安定的な取扱いのためには予め粒子表面を極
薄の酸化皮膜で被覆しておくことが不可欠である。この
ためには、通常、酸素を微量(1,000〜2,000 ppm)含む窒
素気流で徐酸化処理を施すこと等を行うことが好まし
い。According to the SEM observation, the cobalt ultrafine powder of the present invention produced by the above method usually has a primary particle size of less than 100 nm.
(SEM = scanning electron micrographs; the minimum distinguishable particle size is about 10 nm), the aggregate particle size is less than 5000 nm, and the specific surface area is 6-80 m 2 / g. The ultrafine cobalt powder is extremely active as compared with the fine metal powder on the order of submicrons. Therefore, it may ignite and burn in the air even at room temperature. For this reason,
For stable handling in air, it is essential to coat the surface of the particles with an ultrathin oxide film in advance. For this purpose, it is usually preferable to perform gradual oxidation treatment in a nitrogen stream containing a small amount of oxygen (1,000 to 2,000 ppm).
【００１０】[0010]
【実施例】以下, 実施例などによって本発明をさらに具
体的に説明する。 実施例１ 蟻酸コバルト・２水和物 5g に酢酸パラジウム 0.02g
(1900ppm)を添加し、乳鉢で十分に混合した。縦横 100m
m、高さ 10mm のアルミニウム製試料皿に、上記で得た
粉末を均一に敷きつめ、縦横 100mm、厚さ 1mmのアルミ
ニウム板で蓋をし、これをアルミニウム箔で包んだ。減
圧乾燥機中に上記の包みを入れ、1mmHg の減圧下に、速
度 2℃/minで 220℃まで昇温し、60分間保持した。つい
で室温まで冷却した後、2000ppm の酸素含む窒素ガスを
50ミリリットル/minで 1時間導入した後、生成物 １ｇを取り
出した。この粉体をＸ線分析したところ、金属コバルト
であり、SEM から一次粒子径が約 50 nm以下、BET 法に
よる比表面積は 60 m2/g、レーザー方式による凝集粒子
径は 4,000nmであった。 比較例１ 実施例１において、酢酸パラジウムを使用しない他は同
様とした。得られた粉体はコバルト多孔質状の凝集体で
あり、凝集粒子径 13,000nm、比表面積 45 m2/gであっ
た。EXAMPLES The present invention will be described in more detail with reference to the following examples. Example 1 Palladium acetate 0.02 g in 5 g of cobalt formate dihydrate
(1900ppm) was added and mixed well in a mortar. 100m in height and width
The powder obtained above was evenly spread over an aluminum sample dish with a height of 10 mm and a height of 100 mm and a thickness of 1 mm, and the lid was covered with aluminum foil. The above package was put in a vacuum dryer, heated to 220 ° C. at a speed of 2 ° C./min under a reduced pressure of 1 mmHg, and kept for 60 minutes. Then, after cooling to room temperature, nitrogen gas containing 2000 ppm oxygen was added.
After introducing at 50 ml / min for 1 hour, 1 g of product was taken out. When X-ray analysis was performed on this powder, it was found to be metallic cobalt, the primary particle size was about 50 nm or less from SEM, the specific surface area by the BET method was 60 m 2 / g, and the aggregate particle size by the laser method was 4,000 nm. .. Comparative Example 1 The same as in Example 1 except that palladium acetate was not used. The obtained powder was a cobalt porous aggregate, and had an aggregate particle diameter of 13,000 nm and a specific surface area of 45 m 2 / g.
【００１１】実施例２ 実施例１において、蟻酸コバルト・２水和物に代えて、
無水蓚酸コバルトを用い、熱分解保持温度を 300℃とす
る他は同様とした。この結果、一次粒子径 30×100nm
(短径×長径) 、凝集粒子径4,200nm 、比表面積 42 m2/
gのコバルト粉末 2g を得た。 比較例２ 実施例２において、酢酸パラジウムを使用しない他は同
様とした。この結果、一次粒子径 70×300nm(短径×長
径) 、凝集粒子径 17,000nm 、比表面積 13m2/gのコバ
ルト粉末 2g を得た。Example 2 In Example 1, instead of cobalt formate dihydrate,
The same procedure was performed except that anhydrous oxalate was used and the thermal decomposition holding temperature was 300 ° C. As a result, the primary particle size is 30 × 100 nm
(Minor axis x major axis), aggregate particle size 4,200 nm, specific surface area 42 m 2 /
2 g of cobalt powder of g was obtained. Comparative Example 2 The same procedure was performed as in Example 2 except that palladium acetate was not used. As a result, 2 g of cobalt powder having a primary particle size of 70 × 300 nm (minor axis × major axis), agglomerated particle size of 17,000 nm and a specific surface area of 13 m 2 / g was obtained.
【００１２】[0012]
【発明の効果】以上、発明の詳細な説明、実施例、比較
例から明瞭なように、本発明のコバルト超微粉の製造法
によれば、一次粒子径が極めて小さく、凝集性も小さ
く、しかも比表面積の大きいものが容易に製造可能であ
り、コバルト超微粉を工業的に生産する実用的な新規方
法を提供するものでありその意義は極めて大きいもので
ある。As is clear from the detailed description of the invention, the examples, and the comparative examples, according to the method for producing cobalt ultrafine powder of the present invention, the primary particle size is extremely small and the cohesiveness is small, and A material having a large specific surface area can be easily produced, and it provides a practical new method for industrially producing ultrafine cobalt powder, and its significance is extremely large.
Claims (3)
ウムの共存下、非酸化性雰囲気下又は減圧下、 400℃以
下で熱分解し、一次粒子径が 100nm 以下、比表面積が1
0〜80m2/g、凝集粒子径が5,000nm以下であることを特徴
とするコバルト超微粉の製造法1. Cobalt formate or cobalt oxalate is thermally decomposed in the presence of palladium in a non-oxidizing atmosphere or under reduced pressure at 400 ° C. or lower to have a primary particle diameter of 100 nm or less and a specific surface area of 1 or less.
Production method of cobalt ultrafine powder characterized by having an aggregate particle size of 5,000 nm or less with 0 to 80 m 2 / g
である請求項１記載の金属超微粉の製造法2. The rate of temperature rise during the thermal decomposition is 0.5 to 20 ° C./min.
The method for producing ultrafine metal powder according to claim 1, wherein
項１記載の金属超微粉の製造法3. The method for producing ultrafine metal powder according to claim 1, wherein the thermal decomposition temperature is 200 to 360 ° C.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20640991A JPH0565511A (en) | 1991-07-23 | 1991-07-23 | Production of superfine powder of cobalt |
| US07/862,218 US5250101A (en) | 1991-04-08 | 1992-04-02 | Process for the production of fine powder |
| EP92303131A EP0508757A1 (en) | 1991-04-08 | 1992-04-08 | Process for the production of fine powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20640991A JPH0565511A (en) | 1991-07-23 | 1991-07-23 | Production of superfine powder of cobalt |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0565511A true JPH0565511A (en) | 1993-03-19 |
Family
ID=16522890
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20640991A Pending JPH0565511A (en) | 1991-04-08 | 1991-07-23 | Production of superfine powder of cobalt |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0565511A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998026889A1 (en) * | 1996-12-19 | 1998-06-25 | Tomoe Works Co., Ltd. | Ultrafine particles and process for the production thereof |
| CN102699338A (en) * | 2012-05-18 | 2012-10-03 | 宁夏东方钽业股份有限公司 | Method for preparing spherical nickel powder |
| CN105728741A (en) * | 2014-12-09 | 2016-07-06 | 荆门市格林美新材料有限公司 | Nickel powder preparation method and application of nickel powder prepared through same |
-
1991
- 1991-07-23 JP JP20640991A patent/JPH0565511A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998026889A1 (en) * | 1996-12-19 | 1998-06-25 | Tomoe Works Co., Ltd. | Ultrafine particles and process for the production thereof |
| CN102699338A (en) * | 2012-05-18 | 2012-10-03 | 宁夏东方钽业股份有限公司 | Method for preparing spherical nickel powder |
| CN105728741A (en) * | 2014-12-09 | 2016-07-06 | 荆门市格林美新材料有限公司 | Nickel powder preparation method and application of nickel powder prepared through same |
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