KR20140148193A - Manufacturing method of nickel nanopowder and thereby made nickel nanopowder - Google Patents

Abstract

The present invention relates to a producing method of nickel nanopowder and nickel nanopowder produced thereby. According to the producing method of nickel nanopowder, the synthesis time of nickel nanopowder is reduced, a particle size suitable to be used as an inner electrode material of a laminated ceramic condenser can be realized, and the high-yield mass production of nickel nanopowder having a uniform spherical shape is enabled.

Description

Technical Field [0001] The present invention relates to a method of manufacturing a nickel nanopowder and a nickel nanopowder produced thereby,

More particularly, the present invention relates to a process for producing nickel nanopowder and more particularly to a process for producing nickel nanopowder which can easily control the particle size of nickel nanopowder and can produce spherical particles, And a nickel nano powder prepared by the method. The present invention relates to a method for producing a nickel nano powder capable of obtaining a nickel nano powder having a high yield.

Nickel can be applied to various fields such as an electrode material, a catalyst in a fuel cell, a catalyst in a hydrogenation reaction, or a catalyst in various chemical reactions. For example, nickel is used as an internal electrode material of a multilayer ceramic capacitor (MLCC) or as a material for improving the fill factor. In addition, nickel is used as a fuel cell and a catalyst for organic synthesis. Recently, nickel particles have been actively studied as a substitute for noble metal such as platinum. In the case of multilayer ceramic capacitors, the size of the nickel particles used therein is also reduced due to recent tendency toward thinning, miniaturization, and high capacity, and there is an attempt to manufacture nickel particles in nano size.

The nickel nanoparticles can be prepared by liquid phase method, gas phase method, plasma and laser. Among the various methods, a method for producing nanoparticles in a liquid phase at a low manufacturing cost has been recently developed.

Among the methods for preparing nickel nanoparticles on an aqueous solution, sodium hydroxide is added to a mixed solution containing nickel chloride hydrate and hydrazine as a reducing agent (Choi, J.-Y. et al, J. Am Ceram. Soc., 2005, vol.88, p.3020). This process consists of a process in which nickel chloride and hydrazine react to form a complex and then nickel particles are formed by sodium hydroxide. Particularly, the size of the nickel particles can be controlled from 87 nm to 203 nm according to the ratio of nickel chloride / hydrazine / sodium hydroxide. However, in the case of the nickel particles obtained by this method, the particles are necked, so that it is difficult to disperse and the surface of the particles is not smooth, and there is a rough disadvantage.

On the other hand, among various methods of preparing nickel particles using hydrazine as a reducing agent in an aqueous solution, there is a method of controlling the nickel particle size by adding a small amount of cobalt (Kim, K.-M. et al., J. Electroceram. 2006, vol. 17, p. 399).

In this method, nickel chloride or nickel acetate hydrate was used as a nickel precursor. After the nickel precursor and hydrazine were mixed, sodium hydroxide was added to the mixture to prepare nickel particles. It is possible to control the size of the nickel particles by adding a small amount of cobalt chloride to the mixture of the nickel precursor and the hydrazine. The size of the nickel particles synthesized by this method is 150 nm to 450 nm, and the larger the amount of added cobalt, the smaller the size of the nickel particles. The addition of cobalt allows the particle size to be controlled by increasing the number of nuclei, but the surface and necking of the particles obtained is still similar to the previous method.

Another conventional technique for controlling the size of particles by controlling nucleation is to add palladium or silver ions that promote nucleation to a solution containing a nickel precursor and a surfactant, then hydrazine and ammonia, which are reducing agents, (Chou, K.-S. et al., J. Nanoparticle Res. 2001, vol.3, p. 127). The size of the nickel particles produced by this method is 10 nm to 25 nm, and the size of the nickel particles is drastically reduced as compared with the conventional method. However, the synthesized nickel particles contain not only pure nickel but also nickel hydroxide, and the reaction concentration is also very low, so that nickel particles can not be manufactured in large quantities.

A technique for producing nickel particles by pyrolyzing a nickel alkoxide precursor material in addition to a method for producing nickel particles using a nickel precursor and hydrazine as a reducing agent is also known. In this method, a nickel-aminoalkoxy metal complex is synthesized and then the complex is dissolved in an organic solvent such as toluene and heated to pyrolyze the complex to produce nickel particles. The size of the synthesized nickel particles is very small, ranging from 3 nm to 5 nm, but the shape of the particles is different from that of the spherical shape, such as sticks, and the particles are clumped together. Such a manufacturing method requires an additional step of separately preparing the metal complex, and it is difficult to synthesize the metal complex in a large amount, and the particle size is too small to be used as the internal electrode material of the multilayer ceramic capacitor.

Disclosure of the Invention The present invention has been conceived to solve the problems as described above, and it is an object of the present invention to provide a multilayer ceramic capacitor having a uniform particle size, suitable for use as an internal electrode material of a multilayer ceramic capacitor, To provide a method for producing a nickel nano powder capable of obtaining a nano powder and a nickel nano powder prepared thereby.

In order to solve the above-described problems,

(1) preparing a mixture by mixing a nickel precursor, an organic amine and a reducing agent; (2) adding water to the mixture to adjust the water content; And (3) heating the mixture. The present invention also provides a method for producing a nickel nanopowder.

According to a preferred embodiment of the present invention, in the step (2), 9 to 14 parts by weight of water may be added to 100 parts by weight of the nickel precursor contained in the mixture.

According to another preferred embodiment of the present invention, the nickel precursor may be a nickel salt anhydride.

According to another preferred embodiment of the present invention, the nickel precursor is selected from the group consisting of nickel chloride (NiCl ₂ ), nickel sulfate (NiSO ₄ ), nickel acetate (Ni (OCOCH ₃ ) ₂ ), nickel acetylacetonate _{5 H 7 O 2) 2)} , halogenated nickel (NiX _2, wherein, X is F, Br, or I), nickel carbonate (NiCO _3), nickel cyclohexane butyrate _{([C 6 H 11 (CH} 2) 3 CO _{2] 2} Ni), nickel nitrate _{(Ni (nO 3) 2)} , nickel oxalate (NiC ₂ O _4), nickel-steering rate _{(Ni (H 3 C (CH} 2) 16 CO 2) 2) and nickel octanoate ([CH ₃ (CH ₂ ) ₆ CO ₂ ] ₂ Ni) may be used.

According to another preferred embodiment of the present invention, the organic amine is selected from the group consisting of oleyl amine, dodecyl amine, lauryl amine, octyl amine, trioctyl amine trioctyl amine, dioctyl amine, and hexadecyl amine. The term " hexadecyl amine "

According to another preferred embodiment of the present invention, the reducing agent is sodium borohydride (NaBH _4), tetrabutylammonium borohydride _{((CH 3 CH 2 CH 2} CH 2) 4 N (BH 4)), lithium aluminum hydride (LiAlH _4), sodium hydride (NaH), borane-dimethyl amine complex ((CH _{3) 2} NH and BH _3), and the alkane diol _{(HO (CH 2) n OH} , where n is 5≤n≤ 30) may be included.

According to another preferred embodiment of the present invention, the mixture of step (1) may further be mixed with an organic solvent.

According to another preferred embodiment of the present invention, the organic solvent is selected from the group consisting of trioctylphosphine oxide, alkylphosphine, octyl ether, benzyl ether, phenyl ether, hexadecane, heptadecane, octadecane, , Octadecane, oleic acid, lauric acid, stearic acid, misteric acid, and hexetecanoic acid.

According to another preferred embodiment of the present invention, the step (3) may be performed at a temperature ranging from 50 ° C to 450 ° C.

The present invention also provides a nickel nanopowder produced by the above method.

The present invention also provides an internal electrode paste for multilayer ceramic electronic components comprising the nickel nanopowder.

The present invention also provides a nickel nanopowder characterized in that the average particle size is 50 nm or more, and the ratio of the number of particles having a major axis / minor axis ratio of 1.2 or more is 0.03% or less.

According to a preferred embodiment of the present invention, the surface of the nickel nanopowder may be coated with an organic amine.

The present invention also provides an internal electrode paste for multilayer ceramic electronic components comprising the nickel nanopowder.

When the nickel nanopowder is produced by using the method for manufacturing a nickel nanopowder of the present invention, the synthesis time of the nickel nanoparticles can be shortened and the size and shape of the nickel nanoparticles can be more easily controlled, It is possible to mass-produce a nickel nano powder having a spherical shape uniformly while realizing a particle size suitable for use in a high yield.

FIG. 1 is a view showing a result of observing a nickel nano powder prepared according to a conventional manufacturing method in which moisture is not added when the target size is set to 80 nm.
FIG. 2 is a graph showing the results of observing the nickel nanopowder produced according to Example 6. FIG.

Hereinafter, embodiments of the present invention will be described with reference to specific embodiments and the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.

As described above, the conventional method of producing nickel nano powder using the liquid phase method is difficult to disperse, and it is difficult to control the particle size and shape, and mass production is difficult.

Accordingly, the present invention provides a method for preparing a mixture of (1) preparing a mixture by mixing a nickel precursor, an organic amine and a reducing agent; (2) adding water to the mixture to adjust the water content; And (3) heating the mixture. The present invention has been made to solve the above-mentioned problems by providing a method for producing nickel nanopowder.

Thus, it is possible to shorten the synthesis time of the nickel nano powder, and to more easily control the particle size and the shape. Thus, the nickel nano powder having uniformly spherical shape while realizing the particle size suitable for use as the internal electrode material of the multilayer ceramic capacitor Can be mass-produced at a high yield.

first. In the step (1), a nickel precursor, an organic amine and a reducing agent are mixed to prepare a mixture.

The nickel precursor which can be used in the present invention is not particularly limited as long as it is a compound which can be used as a source material of nickel but more preferably nickel chloride (NiCl ₂ ), nickel sulfate (NiSO ₄ ), nickel acetate Ni (OCOCH _{3) 2),} nickel acetylacetonate _{(Ni (C 5 H 7 O} 2) 2), halogenated nickel (NiX _2, wherein, X is F, Br, or I), nickel carbonate (NiCO _3), Nickel cyclohexane butyrate ([C ₆ H ₁₁ (CH ₂ ) ₃ CO ₂ ] ₂ Ni), nickel nitrate (Ni (NO ₃ ) ₂ ), nickel oxalate (NiC ₂ O ₄ ) ₃ C (CH ₂ ) ₁₆ CO ₂ ) ₂ ) or nickel octanoate ([CH ₃ (CH ₂ ) ₆ CO ₂ ] ₂ Ni), or the like. Further, when the nickel salt is hydrated, it is difficult to dissolve the nickel salt, unreacted material may be generated and the yield may be lowered, and since the unreacted material may remain and function as coarse powder, the nickel precursor may be an anhydride of the listed nickel salts Is preferably used.

In the method of manufacturing a nickel nanopowder according to the present invention, an organic amine is added, unlike the conventional method of manufacturing nickel nanoparticles. The organic amine can act as an organic solvent or act as a reducing agent. When an organic amine is added and an additional solvent is further used in the mixture, an organic solvent other than a water-soluble solvent may be used.

According to the present invention, the nickel nanopowder produced by preparing the nickel nanopowder by using the organic amine may be coated with the organic amine, and thus the dispersibility of the nickel nanoparticle into other organic solvent is excellent. Therefore, when the nickel nanopowder is used as an internal electrode of a multilayer ceramic capacitor, for example, it is advantageous that an additional process due to dispersion is unnecessary when dispersed in an organic solvent.

The organic amines which can be used in the present invention include, for example, oleyl amine, dodecyl amine, lauryl amine, octyl amine, trioctyl amine ), Dioctyl amine, or hexadecyl amine, but the present invention is not limited thereto.

When a solvent other than the organic amine is further used in the nickel precursor mixture, an organic solvent may further be used.

As the organic solvent, an ether organic solvent, a saturated hydrocarbon organic solvent (C _n H _{2n + 2} where n is 7? N? 30), an unsaturated hydrocarbon organic solvent (C _n H _2n , n ≤ 30) or an organic acid-based organic solvent may be used alone or in combination.

The ether organic solvents that can be used in the present invention include, for example, trioctylphosphine oxide (TOPO), alkylphosphine, octyl ether, benzyl ether, and phenyl Ether, and phenyl ether, but the present invention is not limited thereto.

The saturated hydrocarbon organic solvent that can be used in the present invention may be any one of hexadecane, heptadecane, and octadecane, but is not limited thereto. The unsaturated hydrocarbon-based organic solvent may be any one of octane, heptadecane, and octadecane, but is not limited thereto.

The organic acid-based organic solvent that can be used in the present invention may be any of oleic acid, lauric acid, stearic acid, mysteric acid, and hexadecanoic acid. But is not limited thereto.

Also, in the nickel precursor mixture, a reducing agent is mixed. Reductants that can be used in the present invention include, for example, sodium borohydride (NaBH ₄ ), tetrabutyammonium borohydride (TBAB) ((CH ₃ CH ₂ CH ₂ CH ₂ ) ₄ N (BH ₄ )), lithium aluminum hydride (LiAlH ₄ ), sodium hydride (NaH), borane dimethylamine complex (CH ₃ ) ₂ NH BH ₃ ) Diol (Alkanediol, HO (CH ₂ ) _n OH, where n is 5? N? 30), but is not limited thereto.

 Next, in step (2), water is added to the mixture to adjust the water content.

When the nickel nanopowder is prepared using the liquid phase method, the particle size of the nickel nanopowder can be controlled by adjusting the concentration of the nickel precursor, the concentration and kind of the reducing agent, or the reaction temperature, respectively, and controlling the synthesis time.

When the nickel nano powder is supersized to 50 nm or less, it is difficult to control the shrinkage, so that the nickel nano powder for the internal electrode of the multilayer ceramic electronic component is preferably 50 nm or more. In the case of 100 nm-class nickel particles, the shrinkage initiation temperature (temperature at which the shrinkage ratio is 5%) is about 200 ° C., and in the case of 50 nm class, it is 180 ° C. However, when it is below 50 nm, shrinkage occurs at a higher temperature. In addition, the existence of an oxide layer can suppress delamination or cracking, and formation of an oxide layer of nickel becomes more important as it goes to fine grains. However, when the thickness is less than 50 nm, formation of an oxide layer is difficult and nickel nanoparticles of 50 nm or more are used.

However, in order to synthesize particles of 50 nm or more according to the conventional production method, the synthesis time becomes long. When the synthesis time becomes longer, the rod-shaped particles grown long in one direction are used instead of the spherical shape in which the particles are symmetrically grown There is a problem that rod-like particles are mixed in addition to spherical shapes. Accordingly, the present invention relates to a method for producing nickel nanoparticles, which comprises adding a predetermined amount of water to a mixture of nickel precursor and organic amine, thereby reducing the synthesis time of nickel nanoparticles, preventing rod- Thereby preparing a powder.

Specifically, water to be added to the mixture may be pure water or distilled water, and 9 to 14 parts by weight of water may be added to 100 parts by weight of the nickel precursor contained in the mixture. When the amount of water to be added is less than 9 parts by weight, it takes a long time to synthesize nickel nanoparticles and rod-like particles are formed. When the amount of water to be added is more than 14 parts by weight, There is a problem that nickel nanoparticles are not synthesized. (See Table 1)

FIG. 1 is a photograph of a nickel nano powder prepared with a target size of 80 nm without adding water to the mixture. As shown in FIG. 1, rod-shaped particles grown in one side are formed between spherical particles . On the other hand, FIG. 2 is a photograph of a nickel nano powder prepared according to Example 6, wherein rod-shaped particles are not formed when 10 parts by weight of water is added, and spherical particles are uniformly formed have.

 Next, in step (3), the mixture is pyrolyzed by heating.

The temperature for heating the nickel precursor mixture may be from 50 캜 to 450 캜, preferably from 60 캜 to 400 캜, more preferably from 80 캜 to 350 캜. The heating time can be performed for 1 minute to 8 hours.

The nickel nanoparticles prepared by thermal decomposition in the nickel nanoparticles according to the present invention may be prepared by, for example, adding ethanol or acetone to a heated nickel precursor mixture to precipitate nickel nanoparticles, and then using a centrifuge .

 The nickel nano powder produced by the above-described manufacturing method can satisfy the average particle size of 50 nm or more and the ratio of the number of particles having the major axis / minor axis ratio of 1.2 or more to 0.03% or less.

The ratio of longest axis to shortest axis refers to the ratio between the longest axis and the shortest axis of a particle when SEM photographs are observed and observed.

 According to the conventional manufacturing method, in order to manufacture nickel nanoparticles of 50 nm or more, the synthesis time is prolonged, and when the synthesis time is prolonged, rod-shaped particles grown long in one direction are produced rather than a symmetrically grown spherical shape .

In order to solve this problem, the present inventors have succeeded in shortening the synthesis time of nickel nanopowder and forming a uniform spherical nickel nanopowder by mixing an organic amine with a nickel precursor and adding a certain amount of water to control the water content .

The nickel nanopowder having an average particle size of 50 nm or more, more preferably 100 to 300 nm, and a ratio of the number of particles having a ratio of major axis / minor axis of 1.2 or more of 0.03% or less according to the present invention forms a uniform spherical shape, The nickel filling rate of the internal electrode can be increased, thereby achieving a dense electrode structure and also having an advantage of suppressing shrinkage.

Therefore, the nickel nanopowder of the present invention is suitable for use in the production of internal electrode paste for multilayer ceramic electronic parts, and it is possible to suppress the electrode breakage phenomenon by securing the surface roughness and securing the nickel filling rate, down voltage and high-temperature reliability can be improved.

The surface of the nickel nanoparticles of the present invention may be coated with an organic amine. Accordingly, when nickel nanoparticles are used later, they are excellent in dispersibility in other organic solvents. Therefore, when the nickel nanopowder is used as an internal electrode of a multilayer ceramic capacitor, for example, it is advantageous that an additional process due to dispersion is unnecessary when dispersed in an organic solvent.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples should not be construed as limiting the scope of the present invention, and should be construed to facilitate understanding of the present invention.

≪ Example 1 >

Preparation of nickel nano powder

In an argon atmosphere, 13 g of anhydrous nickel chloride as a nickel precursor, 200 ml of oleylamine as an organic amine and 0.5 g of tetrabutylammonium borohydride (TBAB) as a reducing agent were added and mixed in a flask, and 0.13 g of After adding distilled water, it was heated to 100 캜. And kept at this temperature for 1 hour. After the temperature of the mixture was raised to 160 ° C, the flask was cooled to room temperature, and 300 mL of ethanol was added to precipitate the nanopowder, and 6.1 g of the nanopowder precipitated by the centrifugal separator was recovered. The reaction yield is 99% or more. The thus-prepared nickel nano powder was observed using an X-ray diffraction analyzer (manufactured by Rikagu), and the average particle diameter of the nickel nano powder was 200 nm.

≪ Examples 2 to 10 >

Except that 0.4 g, 0.65 g, 0.9 g, 1.15 g, 1.3 g, 1.55 g, 1.82 g, 1.95 g, and 2.6 g of distilled water were added to the mixture of the anhydrous nickel chloride, oleylamine and TBAB Was prepared in the same manner as in Example 1.

<Comparative Example>

Except that distilled water was not added to the mixture of the anhydrous nickel chloride, oleylamine and TBAB, and the mixture was heated.

Amount of distilled water added (g) Distilled water addition ratio
(Anhydrous nickel chloride
100 parts by weight) Anhydrous nickel chloride
Whether unreacted material is generated Rod production rate (%)
(Rod: long axis / short axis = 1.2 or more) Example 1 0.13 1 part by weight none 0.10 Example 2 0.4 3 parts by weight none 0.06 Example 3 0.65 5 parts by weight none 0.06 Example 4 0.9 7 parts by weight none 0.04 Example 5 1.15 9 parts by weight none 0.01 Example 6 1.3 10 parts by weight none 0.00 Example 7 1.55 12 parts by weight none 0.00 Example 8 1.82 14 parts by weight none 0.00 Example 9 1.95 15 parts by weight produce - Example 10 2.6 20 parts by weight produce - Comparative Example 0 0 parts by weight none 0.30

As can be seen from Table 1, in the case of the distilled water added to the mixture of anhydrous nickel chloride and organic amine, rod-like particles having a major axis / minor axis ratio of 1.2 or more were significantly reduced compared to the comparative example in which distilled water was not added . In particular, in Examples 5 to 8 in which 9 to 14 parts by weight of distilled water was added to 100 parts by weight of anhydrous nickel chloride, bar-shaped particles were hardly produced without producing unreacted materials, and thus remarkably excellent effects were exhibited.

Table 2 below shows a comparison of the synthesis time of nickel nanoparticles when the amount of water added is different, and shows the synthesis time required to synthesize particles having a size of 200 nm. When 10 parts by weight of distilled water was added, the ratio was expressed based on 1 hour of synthesis time.

Amount of distilled water added (g) Distilled water addition ratio
(Based on 100 parts by weight of anhydrous nickel chloride) Synthesis time ratio of 200 nm particles 0.13 1 part by weight 6.0 0.4 3 parts by weight 4.0 0.65 5 parts by weight 2.0 0.9 7 parts by weight 1.5 1.15 9 parts by weight 1.2 1.3 10 parts by weight 1.0 1.55 12 parts by weight 0.9 1.82 14 parts by weight 0.9 1.95 15 parts by weight Unreacted product 2.6 20 parts by weight Unreacted product 0 0 parts by weight 8.0

As can be seen from the above Table 2, when water was not added, the synthesis time was increased 8 times as compared with 10 parts by weight of water. That is, the present invention of controlling water content by adding water can shorten the synthesis time of nickel nanoparticles, form spherical particles, and is advantageous in productivity improvement and mass synthesis.

Claims (14)

(1) preparing a mixture by mixing a nickel precursor, an organic amine and a reducing agent;
(2) adding water to the mixture to adjust the water content; And
(3) heating the mixture. The method according to claim 1,
Wherein the step (2) comprises adding 9 to 14 parts by weight of water to 100 parts by weight of the nickel precursor contained in the mixture. The method according to claim 1,
Wherein the nickel precursor material is a nickel salt anhydride. The method according to claim 1,
The nickel precursor may be selected from the group consisting of nickel chloride (NiCl ₂ ), nickel sulfate (NiSO ₄ ), nickel acetate (Ni (OCOCH ₃ ) ₂ ), nickel acetylacetonate (Ni (C ₅ H ₇ O ₂ ) ₂ ) NiX _2, wherein, X is F, Br, or I), nickel carbonate (NiCO _3), nickel cyclohexane butyrate _{([C 6 H 11 (CH} 2) 3 CO 2] 2 Ni), nickel nitrate (Ni (NO _{3) 2)} and nickel oxalate (NiC ₂ O _4), Ni-steering rate (Ni (H _3-C (CH _{2), 16} CO _{2) 2)} and nickel octanoate _{([CH 3 (CH 2)} 6 CO 2 ] ₂ Ni). &Lt; / _RTI &gt; The method according to claim 1,
The organic amine may be selected from the group consisting of oleyl amine, dodecyl amine, lauryl amine, octyl amine, trioctyl amine, dioctyl amine, A hexadecyl amine, and a hexadecyl amine. The method for producing a nickel nanopowder according to claim 1, The method according to claim 1,
The reducing agent is sodium borohydride (NaBH _4), tetrabutylammonium borohydride _{((CH 3 CH 2 CH 2} CH 2) 4 N (BH 4)), lithium aluminum hydride (LiAlH _4), sodium hydride ( NaH), borane-dimethyl amine complex ((CH _{3) 2} NH and BH _3), and the alkane diol _{(HO (CH 2) n OH} , where, n at least one selected from the group consisting of 5≤n≤30) is The method of manufacturing a nickel nanopowder according to claim 1, The method according to claim 1,
Wherein the organic solvent is further mixed with the mixture of step (1). 8. The method of claim 7,
The organic solvent is selected from the group consisting of trioctylphosphine oxide, alkylphosphine, octyl ether, benzyl ether, phenyl ether, hexadecane, heptadecane, octadecane, octane, heptadecane, octadecane, oleic acid, lauric acid, An acid, a misteric acid, and a hexetecanoic acid. The method for producing a nickel nanopowder according to claim 1, The method according to claim 1,
Wherein the step (3) is performed at a temperature of 50 to 450 ° C. A nickel nanopowder produced by the manufacturing method according to any one of claims 1 to 9. An internal electrode paste for multilayer ceramic electronic parts comprising the nickel nano powder according to claim 10. A nickel nano powder having an average particle size of 50 nm or more, and a ratio of the number of particles having a major axis / minor axis ratio of 1.2 or more to 0.03% or less. 13. The method of claim 12,
Wherein the nickel nanopowder is coated with an organic amine on its surface. An internal electrode paste for a multilayer ceramic electronic device comprising the nickel nano powder according to claim 12.

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