KR102311541B1 - Silver-carbon nano composite particles, method for preparation thereof, and electric contact material comprising the same - Google Patents

Abstract

The present invention relates to silver-carbon nanocomposite particles usable as an electrical contact material, a manufacturing method thereof, and an electrical contact material including the nanocomposite particles, wherein the nanocomposite particles include silver (Ag) particles; and carbon particles dispersed on the surface and inside of the silver particles.

Description

Silver-carbon nanocomposite particles, a manufacturing method thereof, and an electrical contact material comprising the silver-carbon nanocomposite particles

The present invention relates to a silver-carbon nanocomposite particle, a manufacturing method thereof, and an electrical contact including the silver-carbon nanocomposite particle.

In general, electrical contact materials are current-use contact materials used to control the opening and closing of electrical circuits in electrical devices such as switch-type circuit breakers or switchgear, and are applied to MC, MCB, MCCB, motor switches, switchgear, automobiles and home appliances. do. These electrical contact materials are required to have excellent high melting point, thermal conductivity, electrical conductivity and welding resistance, and low contact resistance in relation to the switching function of electricity, which is their main function. In addition, since the electrical circuit is mechanically connected, a high hardness is required in relation to abrasion resistance.

Electrical contact materials can be classified into small current (1A or less), medium current (1A~1,000A), and large current (1,000A or more) contact materials according to the area and characteristics of the used current. As a contact material for a small current, a material having excellent electrical conductivity is generally used as a material that only plays a role of opening and closing electricity. For medium current contact materials, materials with excellent abrasion resistance and melting point that can withstand high-pressure and high-temperature environments are used as well as electrical conductivity. In addition, as the contact material for a large current, a material with a high melting point satisfying all of the above-described characteristics is used.

Electrical contact materials satisfying the above characteristics can be classified into W-based, Ag-oxide-based, noble metal-based, Cu-based electrical contact materials, etc. depending on the material. Among them, Ag-CdO-based electrical contact materials are widely used. have. However, the Ag-CdO-based electrical contact material has a problem in that as the cadmium oxide content increases, the workability decreases, and the cohesive force between the oxide particles increases, so that the contact resistance increases and the lifespan of the contact decreases. In addition, cadmium (Cd) is regulated by the World Health Organization (WHO) and the World Trade Organization (WTO) as a hazardous substance to the human body and the environment, and its use is gradually regulated by each country, especially throughout Europe. In accordance with the total ban on use, the development of a new contact material to replace Cd is required.

Accordingly, electrical contacts are used by using an oxide alloy such as tin (Sn) or indium (In) instead of cadmium (Cd), but the content of tin and indium is limited to 12 wt% or less due to workability problems. In addition, a silver (Ag)-nickel (Ni)-based alloy containing a high content of nickel (Ni) instead of oxide is being developed, but as the content of nickel (Ni) increases, the processing of the product is difficult, and the electrical conductivity is lowered. Due to the generation of heat generated by the electrical contact, there is a problem of fusion or separation during operation of the electrical contact.

Recently, in order to improve abrasion resistance and electrical properties, silver (Ag)-carbon (C) contact materials have been proposed. Since Ag-C contact materials do not dissolve in each other due to the properties of metals and non-metals, they are mainly manufactured using powder metallurgy. However, when manufactured by powder metallurgy, uniform mixing of silver (Ag) powder and carbon (C) is not achieved, and heat is generated in the portion where the carbon (C) powder is relatively agglomerated, and relatively carbon (C) ), partial dissolution occurs. This reduces the reliability of the electrical contact material. In order to solve this problem, a method such as a powder mixing method has been proposed, but it is difficult to control the size and agglomeration of carbon (C).

The present invention has been devised to solve the above problems, and by newly applying the plasma method instead of the conventional powder metallurgy or powder mixing method, it is possible to manufacture silver-carbon nanocomposite particles as well as to produce carbon particles in the composite particles. It was noted that the degree of dispersion, the degree of aggregation, the size (particle diameter) and the composition can be easily controlled.

Accordingly, an object of the present invention is to provide a silver-carbon nanocomposite particle that can be used as an electrical contact material and a method for manufacturing the same.

Another object of the present invention is to provide an electrical contact material having high hardness and excellent electrical conductivity, including the silver-carbon nanocomposite particles described above.

In order to achieve the above object, the present invention is a silver particle; and silver-carbon nanocomposite particles comprising carbon particles dispersed on the surface and inside of the silver particles.

According to an example, the average particle diameter of the carbon particles may be 5 to 20 nm.

According to an example, the silver particles and carbon particles may be included in a weight ratio of 90:10 to 98:2.

In addition, the present invention provides an electrical contact material comprising the above-described silver-carbon nanocomposite particles.

According to one example, the electrical contact material has a hardness in the range of 68 to 75 Hv and an electrical conductivity in the range of 65 to 85% IACS.

In addition, the present invention provides a method for producing the silver-carbon nanocomposite particles.

According to one example, the present invention comprises the steps of (S100) loading a silver (Ag) raw material into a carbon-based plasma mold of a reaction chamber; and (S200) setting the vacuum degree of the reaction chamber in the range of 0 to 400 torr, adjusting the applied power in the range of 10 to 22.5 kW to generate plasma, and forming silver-carbon nanocomposite particles by the generated plasma Including the above-described silver-provides a method for producing the carbon nanocomposite particles.

According to an example, in the step (S200), an inert gas or a reaction gas in which an inert gas and hydrogen gas are mixed is supplied to the reaction chamber, and the flow rate of the reaction gas may be in the range of 50 to 200 SLM.

According to an example, in the step (S200), a current in the range of 200 to 260 A and a voltage of 50 to 75 V may be applied to the reaction chamber.

According to an example, the carbon particles included in the silver-carbon nanocomposite particles may be generated by a phase transition or desorption of at least a portion of a carbon-based plasma mold by plasma.

In the present invention, by applying the plasma method, it is possible to provide an electrical contact material superior to the silver-carbon electrical contact material manufactured by the conventional powder metallurgy method in terms of electrical conductivity and hardness.

In addition, in the present invention, without limitation to the type or shape of the metal, since the electrical contact material in which silver (Ag)-carbon is dissolved can be configured, electrical contact materials having various sizes, shapes and compositions can be provided. Such an electrical contact material can be usefully applied as an electrical contact material usable for opening/closing and contacting electrical circuits provided in electrical devices such as various switches, relays, electromagnetic switchgear, and circuit breaker.

In addition, in the present invention, since the manufacturing time, manufacturing process, and the number of workers can be reduced by taking advantage of the advantages of the dry method, it is possible to secure a product having higher manufacturing efficiency and superior competitiveness than existing products.

Accordingly, the silver-carbon nanocomposite particles of the present invention can be broadly applied to domestic and overseas markets in various fields using silver (Ag) powder as well as in the field of electrical contact materials.

1 is a view schematically showing a cross-section of a silver-carbon nanocomposite particle according to the present invention.
2 is a TEM photograph showing a cross section of the silver-carbon nanocomposite particles prepared in Example 7.
3 is a TEM photograph showing a cross-section of a composite particle prepared in Comparative Example 3. Referring to FIG.
4 is a SAD pattern image of the silver-carbon nanocomposite particles prepared in Example 7.
5 is a SAD pattern image of the composite particles prepared in Comparative Example 3.
6 and 7 are SEM photographs of the composite particles prepared in Comparative Example 4.
8 and 9 are SEM photographs of the composite particles prepared in Comparative Example 5.
10 is a cross-sectional SEM photograph of the electrical contact material prepared in Comparative Preparation Example 1.
11 is a cross-sectional SEM photograph of the electrical contact material prepared in Preparation Example 1.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

A silver-carbon (Ag-C) contact material, which is one of the conventional electrical contact materials, was manufactured through a powder metallurgy method in which silver powder and carbon powder were respectively weighed to have a predetermined composition and then mixed. However, in the case of the powder metallurgy method, it is difficult to uniformly disperse carbon as well as control the degree of aggregation and size thereof, so that a reliable electrical contact material cannot be obtained.

Therefore, in the present invention, by adopting the plasma method, which is a type of dry method, the composition between silver and carbon is uniform, and the degree of dispersion, degree of aggregation, size (particle diameter), solid solution limit, etc. of carbon particles contained in the formed composite particles can be controlled. Composite particles may be provided.

That is, when producing powder through plasma, when the silver (Ag) raw material is dissolved with high-temperature plasma and then rapidly cooled, the silver (Ag) contained in the silver (Ag) raw material is cooled with a solid solution above the solid solution limit. Supersaturated composite particles (eg, alloy powders) can be prepared. In particular, in the present invention, it is possible to form composite particles including carbon particles derived from a plasma mold by controlling the plasma conditions to a specific range without using a separate carbon material or carbon reaction gas. The carbon material included in the composite particle is a material that increases electrical conductivity and hardness, respectively. In addition, in the present invention, by increasing the uniformity of composition, dispersion, and particle size within the formed silver-carbon nanocomposite particles, durability when applied as an electrical contact material can be increased.

As the silver-carbon nanocomposite particles of the present invention described above have excellent hardness and electrical conductivity, electrical contact materials that can be used for opening and closing electrical circuits provided in electrical devices such as various switches, relays, electromagnetic switchgear, and circuit breaker can be usefully used as

<Silver-carbon nanocomposite particles and electrical contacts including the same>

1 is a cross-sectional view schematically showing a silver-carbon nanocomposite particle according to the present invention.

The silver-carbon nanocomposite particles 10 according to the present invention include silver particles 11 and carbon particles 12 .

The silver particles 11 have high electrical conductivity and low contact resistance, so that the temperature rise during contact is small even at a large current. These silver particles have a non-spherical, irregular shape.

The carbon fine particles 12 have high electrical conductivity and hardness. As shown in FIG. 1 , the carbon particles 12 are dispersed on the surface and inside of the silver particles 11 . At this time, there are no gaps, for example, pores between the carbon particles 12 and the silver particles 11 . That is, the carbon fine particles 12 are tightly adhered to the medium of the silver particles. Accordingly, in the present invention, compared to particles made of only silver particles, abrasion resistance and impact resistance can be improved, and also the workability of electrical contacts can be improved.

The carbon particles 12 are nano-sized particles, and preferably have an average particle diameter of about 5 to 20 nm, more preferably about 5 to 15 nm. Carbon particles having an average particle diameter in the above-mentioned range are not excessively agglomerated with each other, and can be uniformly dispersed on the surface and inside of the silver particles. Therefore, when the silver-carbon nanocomposite particles of the present invention are used as a raw material for an electrical contact, heat generation due to excessive aggregation of carbon particles is minimized and the occurrence of partial dissolution in the contact is reduced, so the reliability of the electrical contact is improved. can be

The shape of the carbon fine particles of the present invention is not particularly limited, and may be a non-spherical, irregular shape. However, the present invention is not limited thereto and may have a spherical shape.

The carbon particles 12 of the present invention may be formed by a phase transition or separation of at least a portion of a carbon-based plasma mold by plasma. These carbon particles 12 may be crystalline, amorphous, or a crystalline structure in which they are mixed. When the carbon particles 12 have a crystalline structure, the electrical conductivity and hardness of the silver-carbon nanocomposite particles can be further increased compared to the amorphous carbon particles.

In the silver-carbon nanocomposite particles according to the present invention, the content ratio of the silver particles to the carbon fine particles is not particularly limited. However, when the silver particles and carbon particles are included in a weight ratio of 90:10 to 98:2, preferably 94:6 to 98:2 by weight, the silver-carbon nanocomposite particles of the present invention have high hardness and electrical conductivity. .

The above-described silver-carbon nanocomposite particles of the present invention may have an average particle diameter in the range of about 1 nm to 1 μm, preferably about 50 to 500 nm, and more preferably about 50 to 150 nm. The silver-carbon nanocomposite particles of the present invention having such an average particle diameter have a purity of 95 to 99.9%, a hardness of about 68 to 75 Hv, and an electrical conductivity of about 65 to 85% IACS. Therefore, the silver-carbon nanocomposite particles of the present invention are technical fields requiring high electrical conductivity, abrasion resistance and fusion resistance, such as electrical contacts, specifically electrical contacts for small currents of 1A or less, as well as 1A or more to less than 1000A. It can be used for medium current or large current over 1000A.

<Method for producing silver-carbon nanocomposite particles>

The silver-carbon nanocomposite particles according to the present invention may be prepared as follows using a plasma method known in the art.

Plasma method is a type of dry method, which ionizes the gas by flowing gas between electrodes of different polarity (plasma state), melts the silver (Ag) raw material by the high heat released by reduction of the ionized gas, and then sprays it into particles will do That is, the ionized plasma gas is emitted between the cathode and the anode in the plasma gun to form high energy. When powder is supplied to such a high-temperature flame, the raw powder melts in a short time and collides to form uniform and fine crystal grains. to form As such, the plasma method not only has a very fast melting and particle formation rate of the raw material powder, but also the formed particles (eg, silver-carbon nanocomposite particles) maintain the composition of the raw material powder almost as it is, so that the composition of newly formed composite particles, It is easy to control the size, structure and dispersion, and various composite materials such as ceramic materials can be easily deposited in addition to existing metals. In addition, the manufacturing time of raw material powder is shortened compared to the conventional wet method, the risk of the process is small and it is eco-friendly, and high purity silver-carbon nanocomposite particles having a smaller size compared to the composite particles prepared by the conventional dry/wet method can be obtained. have.

For an embodiment of the manufacturing method, (S100) the step of loading a silver (Ag) raw material into a carbon-based plasma mold of the reaction chamber; and (S200) setting the vacuum degree of the reaction chamber to 0 to 400 torr, adjusting the applied power to 10 to 22.5 kW to generate plasma, and forming silver-carbon nanocomposite particles by the generated plasma can be configured.

Hereinafter, the manufacturing method is divided into each process step and described as follows.

(i) loading the raw material into the plasma mold ('S100 step')

In step S100, a silver (Ag) raw material is put into a plasma mold (or a crucible).

As the silver (Ag) raw material, a silver-containing compound or a silver alloy may be used without limitation.

In addition, as a mold for plasma-treating the raw material, a mold made of carbon (C) material may be used. By using such a carbon-based plasma mold, later, at least a part of the plasma mold is phase-changed or desorbed by plasma to generate carbon particles. Therefore, in the present invention, unlike the conventional powder alloying method, since it is not necessary to use a separate carbon powder as a raw material, excellent price competitiveness can be obtained.

(ii) Plasma treatment to form silver-carbon nanocomposite particles ('S200 step')

In the step S200, plasma is generated in the reaction chamber loaded with the raw material to form silver-carbon nanocomposite particles.

Specifically, in step S200, the mold on which the raw material is disposed is mounted in the reaction chamber of the plasma equipment, the reaction chamber is closed, and a vacuum is drawn using a pump. When a predetermined degree of vacuum is reached, an inert gas is used to maintain the working vacuum within a predetermined range.

When the working vacuum is maintained, plasma gas is introduced and plasma is generated.

In the plasma treatment step, the conditions of power, time, and working vacuum can be appropriately adjusted within conditions known in the art. For example, the applied power may be 10 to 22.5 kW, preferably 15 to 22.5 kW. In addition, the plasma treatment time may be 10 to 240 minutes, the degree of vacuum may be 0 to 400 torr, preferably 50 to 400 torr. In the plasma treatment step, when the power is less than 10 kW, the yield of the silver-carbon nanocomposite particles may decrease, and when the power exceeds 22.5 kW, the size of the silver-carbon nanocomposite particles may increase. In addition, when the working vacuum degree is less than 0 torr, the plasma distribution is widened and the life of the anode mold for plasma formation is shortened, and when it exceeds 400 torr, the size of the silver-carbon nanocomposite particles may be increased. Therefore, it is preferable that the plasma treatment be performed within the above-mentioned conditions.

As the plasma, various plasmas known in the art may be used without limitation, and, for example, direct current (DC) transfer plasma may be applied. At this time, it is preferable to adjust the applied voltage to 50 to 75 V and the applied current to 200 to 260 A, respectively.

When the plasma treatment is performed under vacuum and an inert atmosphere, oxidation of each raw material powder is prevented, which is preferable. A component of the atmosphere gas for creating such an inert atmosphere is not particularly limited, and examples thereof include argon (Ar), nitrogen (N ₂ ), hydrogen (H ₂ ), methane (CH ₄ ), helium (He), and the like. These can be used individually or in mixture of 2 or more types.

In addition, the component of the reaction gas used for plasma formation is also not particularly limited, and examples thereof include argon (Ar), nitrogen (N ₂ ), hydrogen (H ₂ ), helium (He), and the like. These may be used individually or in mixture of 2 or more types. Specifically, argon, nitrogen, argon + nitrogen, argon + hydrogen, nitrogen + hydrogen may be used. The gas flow rate of the reaction gas is preferably 20 to 200 standard litters per minute (SLM), but is not particularly limited thereto.

The generated plasma has high energy, which causes the silver raw material to undergo phase changes such as vaporization, liquefaction, or sublimation. At the same time, a phase change occurs in at least a portion of the carbon-based plasma mold to which the raw material is injected. Among the phase-changed materials, silver (Ag) with a relatively low melting point is first aggregated and pulverized (eg, silver particles) to form silver (Ag) particles with a relatively large particle size, and then carbon It is powdered to form fine particles uniformly dispersed on the surface and inside of the silver particles. Accordingly, in the present invention, silver particles derived from a silver (Ag) raw material and carbon particles generated by at least a part of a carbon-based plasma mold undergoing phase transition or desorption are included in silver-carbon (Ag-C). ) nanocomposite particles are formed.

After plasma treatment and sufficient cooling, the reaction chamber is opened to take out the formed silver-carbon nanocomposite particles.

The size of the silver-carbon nanocomposite particles of the present invention formed by plasma treatment as described above is not particularly limited, and may be, for example, in the range of about 1 to 1,000 nm. At this time, about 0.3% of the formed composite particles may have a particle size of more than 1,000 nm, which can be reused as a raw material.

Meanwhile, in the present invention, the production of silver-carbon nanocomposite particles using a plasma method, which is a type of dry method, is specifically exemplified. However, the present invention is not limited thereto, and it is also within the scope of the present invention to obtain a powder by a dry method or a wet method known in the art.

<Electrical contact material>

The present invention provides an electrical contact material comprising the above-mentioned silver-carbon nanocomposite particles.

The electrical contact material of the present invention can exhibit excellent hardness and electrical conductivity, including silver and carbon. Specifically, the electrical contact material may have a purity of 99.5% or more, and preferably, the purity may be 99.5 to 99.99%. In addition, the electrical contact material may have a hardness in the range of about 68 to 75 Hv, and an electrical conductivity of about 65 to 85% IACS.

Since the electrical contact material exhibits excellent hardness and electrical conductivity, it is suitable for opening and closing electrical circuits provided in all electrical devices such as various switches, relays, electromagnetic switchgear, and circuit breaker, for example, in technical fields requiring wear resistance and welding resistance. It is preferable to be used for related electric equipment or electric equipment. However, it is not particularly limited thereto, and the above-described silver-carbon nanocomposite particles are applicable to all uses to which they can be applied. For example, it can be used as a functional powder for various uses such as catalysts, cosmetics, food, refrigerators, medical care, clothing, coating layers, purification and washing.

Hereinafter, the present invention will be specifically described by way of examples, but the following examples are only illustrative of one aspect of the present invention, and the scope of the present invention is not limited by the following examples.

[ Example One] - Ag Preparation of -C nanocomposite particles

1 kg of Ag Bulk (purity: 4N) was charged to the carbon mold provided in the 100 kW class DC transfer plasma equipment. After that, the pressure inside the plasma equipment is ^{reduced to 10 -2} torr with a vacuum pump attached to the plasma equipment, and the working vacuum level is increased by injecting an atmosphere gas (gas flow rate: 150 SLM) of nitrogen (N _{2 ) and argon (Ar).} After setting to 200 torr, a plasma reaction gas (N ₂ , a mixed gas of Ar and H ₂ , gas flow rate: 50 SLM) is supplied, and 19.5 kW of power (voltage: 75 V, current: 260 A) is applied. , plasma was generated to prepare Ag-C nanocomposite particles (average particle diameter: 100 nm, average particle diameter of carbon particles: 10 nm) at a rate of 20 g/min.

[ Example 2] - Ag Preparation of -C nanocomposite particles

Ag-C nanocomposite particles (average particle diameter: 100 nm, average particle diameter of carbon fine particles: 10 nm) was prepared.

[Comparative Example 1]

Ag powder (JU-Ag Powder manufactured by Heesung Metal Co., Ltd.) prepared by a wet method was used as Comparative Example 1.

[Experimental Example 1]

The purity of the Ag-C nanocomposite particles prepared in Examples 1 and 2 and the Ag powder of Comparative Example 1 and the impurity content in the particles were analyzed using an inductively coupled plasma (ICP), and the results were analyzed It is shown in Table 1 below. At this time, purity and impurity content in the silver raw material used in Examples 1 and 2, respectively, were also analyzed using inductively coupled plasma. In Table 1 below, the impurity content unit was ppm.

Example 1 Example 2 Comparative Example 1 Ag Bulk Ag-C Nanocomposite Particles Ag Scrap Ag-C Nanocomposite Particles Ag powder impurities Cu 6.5 5.6 305 6.0 5.9 Pd 0 0 One 0.1 0.1 Fe 0.7 0.5 36 0.6 0.7 Bi 0 0.1 2 0.1 0 Zn 4 2.5 5 2.0 2.0 CD 0 0 13 0 0 Ni 0.2 0 21 0 0 Sb 0 0.1 One 0.1 0 Pd 0 0 0 0 0 Mg 0.3 0.2 2 0.1 0.2 Al 0.2 0.2 One 0.3 0.4 Mn 0.4 0.3 2 0.3 0.4 Ca 0.4 0.4 26 0.5 1.5 Cr 0.6 0.6 4 0.8 0.7 Hg 0 0 0 0 0 Au 0.6 0.5 One 0.7 0.5 Pt 0.6 0.5 2 0.6 0.8 total amount 14.5 11.5 422 12.2 13.2 final purity 4N 4N 3N5 4N 4N

As a result of the measurement, the Ag-C nanocomposite particles prepared in Examples 1 and 2 had a purity of 4N, and had a high purity similar to the Ag powder of Comparative Example 1. However, the Ag-C nanocomposite particles of Examples 1 and 2 contained less impurities than the Ag powder of Comparative Example 1.

In addition, the Ag-C nanocomposite particles of Examples 1 and 2 contained less impurities than Ag Bulk and Ag Scrap used as silver raw materials, respectively. In particular, the Ag-C nanocomposite particles of Example 2 had higher purity than Ag Scrap, which is a silver raw material.

As described above, it was confirmed that the Ag-C nanocomposite particles according to the present invention had a low content of impurities and high purity. In addition, it was found that, when the Ag-C nanocomposite particles are produced, high purity Ag-C nanocomposite particles can be manufactured even if the purity of the silver raw material is low because there is a refining effect by using plasma.

[Example 3] to [Example 10], and [Comparative Example 2] to [Comparative Example 5]

Ag-C nanocomposite particles of Examples 3 to 10, Ag nanocomposite particles of Comparative Example 2, and composite particles of Comparative Examples 3 to 5, in the same manner as in Example 1 under the conditions shown in Table 2 below was prepared.

Voltage
(V) electric current
(A) power
(kW) Atmospheric gas flow (SLM) degree of vacuum
(torr) Mold
texture powder making speed
(g/min) of particles
average particle size Example 3 75 200 15.0 150 100 C 13.8 50 nm 4 75 200 15.0 150 200 C 16.3 50 nm 5 75 200 15.0 150 300 C 17.2 100 nm 6 75 200 15.0 150 400 C 18.6 1 μm 7 75 260 19.5 150 200 C 20.4 100 nm 8 75 300 22.5 150 200 C 35.0 1 μm 9 65 200 13.0 150 200 C 17.1 100 nm 10 65 300 19.5 150 200 C 19.3 1 μm Comparative Example 2 65 200 13.0 150 200 Ag 14.5 100nm Comparative Example 3 60 150 9.0 150 200 C 5.8 50 nm Comparative Example 4 100 300 30.0 150 200 C 25.4 10 μm Comparative Example 5 75 200 15.0 150 500 C 19.8 30 μm

In Examples 3 to 10, silver-carbon nanocomposite particles having a uniform distribution of silver and carbon could be prepared, and their average particle diameter could be easily controlled from a few nm to a maximum of 1 μm by changing the plasma generation conditions. I was able to confirm that it could be done.

[Experimental Example 2]

(1) Cross-sections of the Ag-C nanocomposite particles prepared in Example 7 and the composite particles prepared in Comparative Example 3 were confirmed by TEM, and are shown in FIGS. 2 and 3 , respectively.

As can be seen from FIG. 2 , in the Ag-C nanocomposite particles of Example 7, it was confirmed that carbon particles were uniformly dispersed on the surface and inside the Ag particles. On the other hand, in the composite particles of Comparative Example 3, it was confirmed that carbon particles were not present on the surface and inside the Ag particles (see FIG. 3 ).

(2) SAD pattern analysis of the Ag-C nanocomposite particles prepared in Example 7 and the composite particles prepared in Comparative Example 3 was performed, and the results are shown in FIGS. 4 and 5 , respectively.

As a result of the analysis, it was confirmed that the Ag-C nanocomposite particles of Example 7 had a spot pattern of Ag and a ring pattern of C mixed (see FIG. 4 ). On the other hand, in the composite particle of Comparative Example 3, the spot pattern of Ag and the irregular spot pattern of nano-sized Ag were mixed, but the pattern of C could not be confirmed (see FIG. 5).

(3) The composite particles prepared in Comparative Examples 4 and 5 were measured using FESEM equipment, and the results are shown in FIGS. 6 to 9 , respectively.

As can be seen from FIGS. 6 and 7 , the composite particles of Comparative Example 4 had a spherical shape with an average particle diameter of 10 μm, and carbon and silver particles were aggregated and distributed on the particle surface.

On the other hand, the composite particles of Comparative Example 5 had a spherical shape with an average particle diameter of 30 μm, and carbon particles were finely distributed on the particle surface (see FIGS. 8 and 9 ).

(4) The content of carbon particles in each of the Ag-C nanocomposite particles prepared in Examples 3 to 10 was measured using an EDAX analyzer of FESEM equipment, and the results are shown in Table 3 below. In Table 3, the content unit of the carbon fine particles was based on the total amount of the nanocomposite particles as weight %.

Example 3 4 5 6 7 8 9 10 C particulate content 3 3 3 4 5 6 5 5

[ manufacturing example 1] - electricity Manufacture of contact material

The Ag-C nanocomposite particles prepared in Example 7 were sintered in a vacuum furnace at 900° C. for 10 hours to obtain a sintered body, and then the sintered body was compressed at a high temperature at 500° C. to obtain a compression material (density: 99% or more) , it was extruded to prepare an electrical contact material.

[comparison manufacturing example 1] - Manufacture of electrical contact material

A mixed powder was obtained by uniformly mixing 95 wt% of Ag powder and 5 wt% of carbon powder.

Thereafter, an electrical contact material was prepared in the same manner as in Preparation Example 1, except that the mixed powder was used instead of the Ag-C nanocomposite particles used in Preparation Example 1.

[comparison manufacturing example 2] - Manufacture of electrical contact material

An electrical contact material was prepared in the same manner as in Preparation Example 1, except that pure silver powder was used instead of Ag-C nanocomposite particles.

[ Experimental example 3] - Ag -C evaluation of dispersibility of carbon fine particles in nanocomposite particles

The cross-sections of the electrical contact materials prepared in Preparation Example 1 and Comparative Preparation Example 1, respectively, were confirmed by SEM, and the results are shown in FIGS. 10 and 11, respectively.

In the SEM photograph of the electrical contact material prepared in Comparative Preparation Example 1, the carbon powder was present as it was, and it was found that the carbon powder was non-uniformly distributed in the composite particles, and partially aggregated to form agglomerates (see FIG. 10 ). On the other hand, in the SEM photograph of the electrical contact material prepared in Preparation Example 1, separate carbon particles could not be identified (see FIG. 11 ).

From this, it could be indirectly confirmed that in the nanocomposite particles according to the present invention, carbon was uniformly dispersed throughout the surface and inside of the nanocomposite particles in the form of fine particles.

[ Experimental example 4] - Evaluation of physical properties of electrical contact materials

The electrical conductivity and hardness of the electrical contact materials prepared in Preparation Example 1 and Comparative Preparation Examples 1 and 2, respectively, were measured as follows, and the results are shown in Table 4 below.

Here, the hardness was measured using a Vickers hardness tester and maintained for 10 seconds under a load of 300 g. In addition, electrical conductivity was expressed as %IACS through unit conversion after measuring specific resistance.

Preparation Example 1 Comparative Preparation Example 1 Comparative Preparation Example 2 Hardness (Hv) 71 65 55 Electrical Conductivity (%IACS) 65-75 60~65 99 to 100

As shown in Table 4, it was confirmed that the electrical contact material manufactured by the present invention had superior properties in terms of electrical conductivity and hardness than the electrical contact materials of Comparative Preparation Examples 1 and 2.

Specifically, the electrical contact material of Comparative Preparation Example 1 prepared by the conventional powder mixing method exhibited a hardness of 65 Hv. In contrast, the hardness of the electrical contact material of Preparation Example 1 was 71 Hv. In addition, while the electrical conductivity of Comparative Preparation Example 1 was 60 to 65 % IACS, the electrical conductivity of Preparation Example 1 was 65 to 75 % IACS.

Therefore, it was confirmed that the electrical contact material comprising the silver-carbon-metal-based nanocomposite particles of the present invention can be usefully used as an electrical contact material with improved welding resistance and wear resistance as it has high hardness and excellent electrical conductivity.

10: silver-carbon nanocomposite particles, 11: silver particles,
12: carbon fine particles

Claims (11)

Manufactured by a plasma method using a carbon-based plasma mold,
silver particles; and
At least a portion of the carbon-based plasma mold is generated by a phase transition or desorption by plasma, and has an average particle diameter of 5 to 20 nm, and carbon particles dispersed on the surface and inside of the silver particles.
including,
The silver particles and carbon particles are included in a weight ratio of 90:10 to 96:4 silver-carbon nanocomposite particles. delete delete According to claim 1,
A silver-carbon nanocomposite particle having an average particle diameter of 10 to 1,000 nm. According to claim 1,
Silver-carbon nanocomposite particles having a purity in the range of 95 to 99.9%, a hardness in the range of 68 to 75 Hv, and an electrical conductivity in the range of 65 to 85% IACS. An electrical contact material comprising the silver-carbon nanocomposite particles according to any one of claims 1, 4 and 5. 7. The method of claim 6,
An electrical contact material having a hardness in the range of 68 to 75 Hv, and an electrical conductivity in the range of 65 to 85% IACS. (S100) loading a silver (Ag) raw material into a carbon-based plasma mold of the reaction chamber; and
(S200) The vacuum degree of the reaction chamber is set in the range of 0 to 400 torr, the applied power is adjusted in the range of 10 to 22.5 kW to generate plasma, and at least a portion of the carbon-based plasma mold is phase-changed by the generated plasma ( phase transition) or desorption to form silver-carbon nanocomposite particles in which carbon particles are dispersed on the surface and inside of the silver particles
The method of claim 1, including silver-carbon nanocomposite particles. 9. The method of claim 8,
In the step (S200),
An inert gas or a reaction gas in which an inert gas and hydrogen gas are mixed is supplied to the reaction chamber,
The flow rate of the reaction gas is in the range of 50 to 200 SLM-A method of producing a carbon nanocomposite particle. 9. The method of claim 8,
In the step (S200),
A current in the range of 200 to 260 A and a voltage of 50 to 75 V are applied to the reaction chamber. A method of manufacturing silver-carbon nanocomposite particles. delete

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