JP2001049301A - Method for modifying surface of fine metal powder - Google Patents
Method for modifying surface of fine metal powderInfo
- Publication number
- JP2001049301A JP2001049301A JP11222458A JP22245899A JP2001049301A JP 2001049301 A JP2001049301 A JP 2001049301A JP 11222458 A JP11222458 A JP 11222458A JP 22245899 A JP22245899 A JP 22245899A JP 2001049301 A JP2001049301 A JP 2001049301A
- Authority
- JP
- Japan
- Prior art keywords
- metal powder
- fine metal
- atmosphere
- powder
- partial pressure
- 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
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- Powder Metallurgy (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、電子材料用の微細
な金属粉末の表面を改質する方法に関し、特に、表面に
酸化皮膜を付与し、耐酸化性と焼結性に優れた電子材料
用の微細な金属粉を得る方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for modifying the surface of fine metal powder for electronic materials, and more particularly, to an electronic material having an oxide film on its surface and excellent in oxidation resistance and sinterability. The present invention relates to a method for obtaining fine metal powder for use.
【０００２】[0002]
【従来の技術】電子材料の小型化と高集積化において
は、ニッケルをはじめとする微細金属粉末の用途が拡大
している。たとえば、積層セラミックコンデンサーに用
いられる微細金属粉末は、工程の連続化のために、ペー
スト状した後、グリーンシートとして多層に積層され、
目的の形状に加工された後、高温度で焼結される。この
焼結工程の雰囲気としては、脱バインダーのために弱酸
化性雰囲気が使用されている。2. Description of the Related Art In miniaturization and high integration of electronic materials, applications of fine metal powders such as nickel are expanding. For example, the fine metal powder used in the multilayer ceramic capacitor is pasted into a paste, and then laminated as a green sheet in multiple layers for continuation of the process.
After being processed into a desired shape, it is sintered at a high temperature. As the atmosphere in the sintering step, a weakly oxidizing atmosphere is used for debinding.
【０００３】この工程において、ペーストにする際に、
微細金属粉の表面性状が、分散性に大きく影響する。す
なわち、金属表面である場合は、金属同士の凝集性が大
きくなり、分散性が悪くなる。他方、表面が酸化され過
ぎると表面の凹凸が多くなり、結果として比表面積の増
大となり、この場合には充填性の低下に繋がる。このた
め、微細金属粉の表面に薄くて緻密な酸化物層を形成す
ることが有効であると考えられることから、種々の表面
改質方法が検討されている。In this process, when making a paste,
The surface properties of the fine metal powder greatly affect the dispersibility. That is, in the case of a metal surface, the cohesion between the metals increases, and the dispersibility deteriorates. On the other hand, if the surface is excessively oxidized, the unevenness of the surface increases, resulting in an increase in the specific surface area, and in this case, a decrease in the filling property. For this reason, since it is considered effective to form a thin and dense oxide layer on the surface of the fine metal powder, various surface modification methods are being studied.
【０００４】たとえば、鉄鋼材料表面の酸化皮膜生成に
は、黒皮処理法と呼ばれる酸化皮膜の形成方法が行われ
ているが、この方法を微細な金属粉に応用しようとする
と、微細金属粉の場合、容易に酸化してしまい、反応が
急激に進行する。よって、表面部のみを酸化させること
ができず、金属粉末全体が酸化することとなり、酸素含
有量が急激に増加し、表面部のみに適当な膜厚の酸化皮
膜を生成させることは、困難であった。[0004] For example, to form an oxide film on the surface of a steel material, a method of forming an oxide film called a black scale treatment method is performed. In this case, it is easily oxidized, and the reaction proceeds rapidly. Therefore, only the surface portion cannot be oxidized, and the entire metal powder is oxidized, the oxygen content increases rapidly, and it is difficult to form an oxide film having an appropriate thickness only on the surface portion. there were.
【０００５】[0005]
【発明が解決しようとする課題】本発明の目的は、微細
金属粉の表面に酸化皮膜を生成させ、耐酸化性を有し、
有機溶剤中において分散性あるいは充填性に優れ、ペー
スト特性として薄膜化が可能で焼結性に優れた電子材料
用の微細な金属粉の製造方法を提供することである。SUMMARY OF THE INVENTION An object of the present invention is to form an oxide film on the surface of fine metal powder, to have oxidation resistance,
An object of the present invention is to provide a method for producing a fine metal powder for an electronic material, which is excellent in dispersibility or filling property in an organic solvent, can be formed into a thin film as paste properties, and is excellent in sinterability.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するた
め、本発明は、Ｈ２、ＣＯ、Ｈ２Ｏ、ＣＯ２、を含む雰
囲気中で酸素分圧を制御し、極めて弱い酸化性雰囲気中
での微細金属粉の低温熱処理による微細金属粉の表面改
質方法である。In order to achieve the above object, the present invention provides a method for controlling the partial pressure of oxygen in an atmosphere containing H 2 , CO, H 2 O, and CO 2 , and for controlling the oxygen partial pressure in an extremely weak oxidizing atmosphere. This is a method for modifying the surface of the fine metal powder by low-temperature heat treatment of the fine metal powder in the above.
【０００７】すなわち、前記雰囲気で、２００℃以上５
００℃以下において、酸素分圧を、１０−５０気圧以上
１０−１５気圧以下に制御し、微細金属粉の表面を１０
オングストローム以上１００オングストローム以下の緻
密な酸化物層で被覆する方法である。That is, in the above atmosphere, the temperature is 200 ° C. or more,
At 00 ° C. or lower, the oxygen partial pressure is controlled to 10 −50 atm or more and 10 −15 atm or less, and the surface of the fine metal powder is
This is a method of covering with a dense oxide layer having a thickness of Å to 100 Å.
【０００８】この方法においては、前記温度範囲で、Ｌ
ｏｇ（Ｈ２／Ｈ２Ｏ）あるいはＬｏｇ（ＣＯ／ＣＯ２）
を、６以上１６以下に制御する方法が有効である。ま
た、具体的には、雰囲気中にメタノール、あるいはエタ
ノール等の低級アルコールを含有させる方法が実用的で
ある。さらに微細金属粉の表面をより均一に処理するた
めに、粉末と気相が均一に縣濁した状態を保つように、
流動層の形成が可能な反応容器を用いることも有効であ
る。[0008] In this method, in the above temperature range, L
og (H 2 / H 2 O) or Log (CO / CO 2 )
Is controlled to be 6 or more and 16 or less. Further, specifically, a method in which a lower alcohol such as methanol or ethanol is contained in the atmosphere is practical. In order to further uniformly treat the surface of the fine metal powder, keep the powder and gas phase in a uniformly suspended state.
It is also effective to use a reaction vessel capable of forming a fluidized bed.
【０００９】本発明の方法は、微細金属粉の平均粒径が
１μｍ以下で０．１μｍ以上の範囲のニッケルをはじ
め、鉄、コバルト、銅の粉末の表面を処理する方法とし
て適用できる。The method of the present invention can be applied as a method for treating the surface of powders of nickel, iron, cobalt, and copper, including nickel in which the average particle size of the fine metal powder is 1 μm or less and 0.1 μm or more.
【００１０】[0010]
【発明の実施の形態】微細金属粉表面に緻密な酸化皮膜
を生成させ、耐酸化性を有し、有機溶剤中において分散
性あるいは充填性に優れ、ペースト特性として薄膜化が
可能で焼結性に優れた特性を有する電子材料用の微細な
金属粉末とするためには、酸素分圧を制御した極めて弱
い酸化性雰囲気中で、微細金属粉の低温熱処理を行い、
微細金属粉の表面を１０オングストローム以上１００オ
ングストローム以下の緻密な酸化物層で被覆すれば良
い。BEST MODE FOR CARRYING OUT THE INVENTION A fine oxide film is formed on the surface of a fine metal powder, has oxidation resistance, is excellent in dispersibility or filling property in an organic solvent, can be made into a thin film as a paste property, and has sinterability. In order to obtain fine metal powder for electronic materials with excellent properties, low-temperature heat treatment of the fine metal powder is performed in an extremely weak oxidizing atmosphere with controlled oxygen partial pressure,
The surface of the fine metal powder may be covered with a dense oxide layer having a thickness of 10 Å to 100 Å.
【００１１】酸化物層の皮膜の厚さは、最大で金属粉末
の粒径の１／１００程度が適当である。たとえば、平均
粒径が１μｍの金属粉末の場合は、最大層厚は、１００
オングストローム、最小層厚は、１０オングストローム
程度が適当である。層厚が１０オングストローム以下で
は、内部を酸化から保護する効果が得られず、１００オ
ングストローム以上の層厚の皮膜を生成させても効果
は、ほとんど変わらない。The appropriate thickness of the oxide layer is about 1/100 of the particle size of the metal powder. For example, in the case of a metal powder having an average particle size of 1 μm, the maximum layer thickness is 100
Angstrom and the minimum layer thickness are suitably about 10 Å. If the thickness is less than 10 angstroms, the effect of protecting the inside from oxidation cannot be obtained, and even if a film having a thickness of 100 angstroms or more is formed, the effect is hardly changed.
【００１２】酸化物層の生成温度は、２００℃以下で
は、反応速度が遅く経済的ではない。また、５００℃以
上とすると、安定した流動層を得るための設備が確保し
にくくなるので２００℃から５００℃程度が適当であ
る。また、低級アルコールを添加する場合は、この温度
範囲であれば、容易に、目的とする酸素分圧が得られ、
安定して、所望の酸化物層を有する金属粉が得られる。If the formation temperature of the oxide layer is 200 ° C. or less, the reaction rate is low and it is not economical. If the temperature is 500 ° C. or higher, it is difficult to secure equipment for obtaining a stable fluidized bed. Also, when adding a lower alcohol, within this temperature range, the desired oxygen partial pressure can be easily obtained,
A metal powder having a desired oxide layer can be obtained stably.
【００１３】反応雰囲気は、窒素、アルゴンなどの中性
雰囲気中に、Ｈ２、ＣＯ、Ｈ２Ｏ、ＣＯ２、等のガスを
混入させることによって、酸素分圧を、１０−５０気圧
以上、１０−１５気圧以下に制御すれば良い。ここでＬ
ｏｇ（Ｈ２／Ｈ２Ｏ）あるいはＬｏｇ（ＣＯ／ＣＯ２）
を、６以上１６以下に制御する方法が有効であるが、よ
り具体的には、雰囲気中にメタノール、あるいはエタノ
ール等の低級アルコールを含有させる方法が容易かつ実
際的な方法である。これらアルコール類の気相中の含有
量は、設備安全性等を考慮すると、１０体積％程度以下
が適当である。As a reaction atmosphere, a gas such as H 2 , CO, H 2 O, CO 2 , or the like is mixed into a neutral atmosphere such as nitrogen or argon to increase the oxygen partial pressure to 10 -50 atm or more. What is necessary is just to control to 10-15 atmospheres or less. Where L
og (H 2 / H 2 O) or Log (CO / CO 2 )
Is effective, but more specifically, a method in which a lower alcohol such as methanol or ethanol is contained in the atmosphere is an easy and practical method. The content of these alcohols in the gas phase is suitably about 10% by volume or less in consideration of equipment safety and the like.
【００１４】さらに微細金属粉に均一に処理するために
粉末と気相が均一に縣濁した状態を保つために流動層の
形成が可能な反応容器を用いることも有効であり、反応
時間は、反応温度、物量により選択すれば良い。以下実
施例としてニッケル粉末の表面処理の例を説明するが、
この方法は微細金属粉として、鉄、コバルト、銅等の金
属粉の表面を処理する方法としても適用可能である。It is also effective to use a reaction vessel capable of forming a fluidized bed in order to keep the powder and the gas phase uniformly suspended in order to uniformly treat the fine metal powder. It may be selected depending on the reaction temperature and amount. Hereinafter, an example of surface treatment of nickel powder will be described as an example,
This method is also applicable as a method for treating the surface of a metal powder such as iron, cobalt, or copper as fine metal powder.
【００１５】[0015]
【実施例】（実施例１）（湿式法） 塩化ニッケル溶液に苛性ソーダを添加しｐＨを７．５に
した調整し生成した水酸化ニッケルスラリー中にヒドラ
ジンを添加することにより、平均粒径１μｍの微細ニッ
ケル粉を得た。前記ニッケル粉の表面に緻密で薄い酸化
物層を形成するため、反応容器に低級アルコールとして
メタノールを１体積％含んだＮ２ガスを吹き込み粉末と
気相が均一に縣濁した状態を保った流動層を形成しなが
ら、微細ニッケル粉末の表面処理を３００℃にて５分間
行なった。(Example 1) (Wet method) Adjusting the pH to 7.5 by adding caustic soda to a nickel chloride solution and adding hydrazine to the resulting nickel hydroxide slurry, an average particle diameter of 1 µm was obtained. A fine nickel powder was obtained. To form a dense and thin oxide layer on the surface of the nickel powder, keeping the state in which the powder and the vapor blowing methanol 1% by volume inclusive N 2 gas are uniformly suspended as a lower alcohol to the reaction vessel, fluidized While forming the layer, the surface treatment of the fine nickel powder was performed at 300 ° C. for 5 minutes.
【００１６】表面処理された微細ニッケル粉は、バグフ
イルターにて回収した。回収された微細金属粉の表面を
ＴＥＭ観察したところ１００オングストロームの緻密な
酸化物層で被覆されていた。酸素品位は１．０重量％で
あった。また比表面積は、５ｍ２／ｇであった。空気中
でのＤＴＡ／ＴＧによる重量変化では、５００℃まで重
量の増大、すなわち酸化は殆ど観察されなかった。 （実施例２）（乾式法） 塩化ニッケル蒸気を高温水素還元して得られた平均粒径
１μｍの微細ニッケル粉の表面に緻密で薄い酸化物層を
形成するため、反応容器に低級アルコールとしてエタノ
ールを１体積％含んだＮ２ガスを吹き込み粉末と気相が
均一に縣濁した状態を保った流動層を形成しながら、微
細ニッケル粉末の表面処理を４００℃にて５分間行なっ
た。The surface-treated fine nickel powder was collected by a bag filter. When the surface of the collected fine metal powder was observed by TEM, it was found to be covered with a dense oxide layer of 100 Å. The oxygen quality was 1.0% by weight. The specific surface area was 5 m 2 / g. In the weight change by DTA / TG in air, weight increase, that is, oxidation was hardly observed up to 500 ° C. (Example 2) (Dry method) In order to form a dense and thin oxide layer on the surface of fine nickel powder having an average particle diameter of 1 μm obtained by reducing hydrogen chloride at high temperature with hydrogen, ethanol was used as a lower alcohol in a reaction vessel. Was subjected to surface treatment at 400 ° C. for 5 minutes while blowing a N 2 gas containing 1% by volume of N 2 to form a fluidized bed in which the powder and the gas phase were kept in a uniformly suspended state.
【００１７】表面処理された微細ニッケル粉は、バグフ
イルターにて回収した。回収された微細金属粉の表面を
ＴＥＭ観察したところ１００オングストロームの緻密な
酸化物層で被覆されていた。酸素品位は０．７重量％で
あった。また比表面積は、３ｍ２／ｇであった。空気中
でのＤＴＡ／ＴＧによる重量変化では、６００℃まで重
量の増大、すなわち酸化は殆ど観察されなかった。The surface-treated fine nickel powder was collected by a bag filter. When the surface of the collected fine metal powder was observed by TEM, it was found to be covered with a dense oxide layer of 100 Å. The oxygen grade was 0.7% by weight. The specific surface area was 3 m 2 / g. In the weight change by DTA / TG in air, weight increase up to 600 ° C., that is, almost no oxidation was observed.
【００１８】[0018]
【発明の効果】本発明の方法を用いることによって、微
細金属粉の表面を薄くて緻密な酸化物層で被覆するがで
きる。したがって、微細金属粉の耐酸化性を向上できる
とともに、ペーストに用いられている有機溶剤中におい
ても分散性が良好で、かつ充填性の良好な粉末が得られ
る。この結果、ペーストの薄層化が可能となり電子材料
の小型化や高集積化に寄与するところ大である。According to the method of the present invention, the surface of the fine metal powder can be covered with a thin and dense oxide layer. Therefore, the oxidation resistance of the fine metal powder can be improved, and a powder having good dispersibility and good filling property in the organic solvent used for the paste can be obtained. As a result, the paste can be made thinner, which greatly contributes to miniaturization and high integration of electronic materials.
Claims (4)
℃以上、５００℃以下の温度において、反応容器中の酸
素分圧を１０−５０気圧以上１０−１５気圧以下に制御
した雰囲気とし、微細金属粉の表面を１０オングストロ
ーム以上１００オングストローム以下の緻密な酸化物層
で被覆することを特徴とする微細金属粉の表面改質方
法。1. A fine metal powder is charged into a reaction vessel,
At a temperature of 500 ° C. or more and 500 ° C. or less, an atmosphere in which the oxygen partial pressure in the reaction vessel is controlled at 10 −50 atm or more and 10 −15 atm or less, and the surface of the fine metal powder is densely oxidized at 10 Å to 100 Å. A method for modifying the surface of fine metal powder, characterized by coating with a material layer.
ールを含有することを特徴とする請求項１に記載の微細
金属粉の表面改質方法。2. The method for modifying the surface of fine metal powder according to claim 1, wherein the atmosphere contains methanol or ethanol.
属粉と気相が均一に縣濁した状態を保つことを特徴とす
る請求項１または２に記載の微細金属粉の表面改質方
法。3. The surface modification of a fine metal powder according to claim 1, wherein a fluidized bed is formed in the reaction vessel to maintain a state in which the fine metal powder and the gas phase are uniformly suspended. Method.
ケル粉である請求項１から３のいずれかに記載の微細金
属粉の表面改質方法。4. The method for modifying the surface of a fine metal powder according to claim 1, wherein the fine metal powder is a nickel powder having an average particle size of 1 μm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11222458A JP2001049301A (en) | 1999-08-05 | 1999-08-05 | Method for modifying surface of fine metal powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11222458A JP2001049301A (en) | 1999-08-05 | 1999-08-05 | Method for modifying surface of fine metal powder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001049301A true JP2001049301A (en) | 2001-02-20 |
Family
ID=16782740
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11222458A Pending JP2001049301A (en) | 1999-08-05 | 1999-08-05 | Method for modifying surface of fine metal powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2001049301A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002081131A1 (en) * | 2001-03-30 | 2002-10-17 | Catalysts & Chemicals Industries Co., Ltd. | Fine metal particles, method for preparing said particles, coating liquid containing said fine particles for forming transparent electroconductive film, substrate with transparent electroconductive film, and display |
| WO2004067211A1 (en) * | 2003-01-31 | 2004-08-12 | Toho Titanium Co., Ltd. | Fine metal powder, process for producing the same, and conductive paste containing the fine metal powder |
| JP2012122126A (en) * | 2010-12-10 | 2012-06-28 | Central Research Institute Of Electric Power Industry | Surface-modified copper member |
| JP2012122125A (en) * | 2010-12-10 | 2012-06-28 | Central Research Institute Of Electric Power Industry | Method for manufacturing surface-modified copper member, catalyst member and organic synthesis method using the same |
-
1999
- 1999-08-05 JP JP11222458A patent/JP2001049301A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002081131A1 (en) * | 2001-03-30 | 2002-10-17 | Catalysts & Chemicals Industries Co., Ltd. | Fine metal particles, method for preparing said particles, coating liquid containing said fine particles for forming transparent electroconductive film, substrate with transparent electroconductive film, and display |
| US7494710B2 (en) | 2001-03-30 | 2009-02-24 | Jgc Catalysts And Chemicals Ltd. | Fine metal particles suitable for forming a conductive coating film |
| WO2004067211A1 (en) * | 2003-01-31 | 2004-08-12 | Toho Titanium Co., Ltd. | Fine metal powder, process for producing the same, and conductive paste containing the fine metal powder |
| JP2012122126A (en) * | 2010-12-10 | 2012-06-28 | Central Research Institute Of Electric Power Industry | Surface-modified copper member |
| JP2012122125A (en) * | 2010-12-10 | 2012-06-28 | Central Research Institute Of Electric Power Industry | Method for manufacturing surface-modified copper member, catalyst member and organic synthesis method using the same |
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