KR20100137633A - Metal-glass nano composite powders - Google Patents

Abstract

PURPOSE: Metal-glass nanocomposite powder and producing method thereof are provided to synthesize the metal-glass nanocomposite powder capable of maintaining a perfect circular shape through a flame spray pyrolysis process. CONSTITUTION: A producing method thereof of metal-glass nanocomposite powder comprises the following steps: dissolving a precursor material containing components of metal and glass to distilled water or alcohol to form a precursor solution; inserting the precursor solution to a spray device for producing droplets with the diameter of 0.1~100micrometers; and inserting the droplets to a diffusion flame reactor to produce the metal-glass nanocomposite powder by a flame spray pyrolysis process.

Description

Metal-glass nano composite powders

The present invention relates to a metal-glass nanocomposite powder, and more particularly, to a method of preparing a metal and glass nanocomposite powder exhibiting a uniform particle size distribution and maintaining a perfect spherical shape by applying a flame spray pyrolysis process. The present invention relates to a metal and glass nanocomposite powder prepared from the present invention, a conductive electrode paste composition prepared from the powder, and a patterned electrode prepared from the electrode paste composition.

In general, the conductive paste composition is formed by mixing a conductive metal powder, glass frit, and an organic vehicle. The conductive paste composition is applied to various components to be electrically connected by screen printing, immersion, offset, inkjet printing, etc., and then dried and sintered. It serves as an electrode.

As the conductive metal powder, silver, gold, copper, nickel, aluminum, magnesium, palladium, etc., which are excellent in electrical conductivity, are used alone or in combination of two or more thereof. The glass frit provides bonding strength after firing between the conductive metal powder and the applied part.

Since metal powders, which are mainly used as electrode materials, are synthesized by a gas phase method or a liquid phase method, most of them have a spherical shape. In addition, glass frit powder synthesis technology uses a conventional melting method.

Under the conventional process, the molten raw material was quenched in the form of a flake, and then synthesized glass frit powder having a desired particle size through milling and classification. However, the above-described method is essential to the milling and classification process of several steps, which has disadvantages such as deterioration of the glass frit powder, a large number of unit steps, yield reduction to obtain a powder of the desired particle size.

Although many disadvantages have been overcome at present, there are still disadvantages, and much effort has been put into paste manufacturing techniques to overcome the problem of dispersibility.

As electrode materials, metal powders have various sizes ranging from tens of nanometers to several microns. On the other hand, the traditional methods present difficulties in nano-sizing glass powders. Thus, different size morphological properties of silver and glass powders make it difficult to produce stable pastes.

Accordingly, the present inventors have made efforts to directly prepare nano-sized composite powders of metal and glass that can be directly applied for electrodes.As a result, flame spray pyrolysis processes for synthesizing nano powders simultaneously form components of metal and glass frit in a spray solution. The present invention was completed by preparing a nanocomposite powder of spherical metal and glass by dissolving and applying.

As a result, the present invention provides a method for preparing a nano-size composite powder of metal and glass that can simultaneously solve the non-uniformity of the distribution of the glass powder and the instability of the paste that may occur in the process of pasting the metal powder and glass frit. Its main purpose is to provide.

In addition, another object is to provide a nano-sized composite powder of metal and glass prepared by the method of the present invention, and an electrode paste composition further comprising an organic component in the powder.

In addition, the present invention has another object to provide a patterned electrode prepared by applying the electrode paste composition on a substrate and dried.

In order to achieve the above object, the present invention provides a method for producing a metal and glass nanocomposite powder by applying a flame spray pyrolysis process, which is an economical process with a small number of unit processes in a continuous process.

In the present invention, the metal and glass are mixed in the range of 90 to 99.5% by weight and 0.5 to 10% by weight relative to the total weight, respectively, the metal and glass are easily dissolved in a solvent such as water or alcohol It can be used in the form of precursors of salts such as acetate, nitrate, chloride, hydrate and oxide.

The present invention also provides a metal glass nanocomposite powder having a spherical shape prepared by the above method.

The present invention also provides an electrode paste composition further comprising an organic component in the metal glass nanocomposite powder.

The present invention also provides a patterned electrode prepared by applying the electrode paste composition on a substrate and then drying.

The present invention is capable of synthesizing a large amount of nanocomposite powder of metal and glass showing a uniform particle size distribution and maintaining a perfect spherical shape.

In addition, by adjusting the type and flow rate of the fuel gas, the flow rate of oxygen or air, and the ratio of the fuel gas, the metal and glass composites have various structures such as a structure in which the glass component surrounds the metal and a structure in which the glass component is dispersed in the metal powder. Powders can be prepared.

In addition, since the phase separation of the metal and glass does not occur when the paste is prepared using the nanocomposite powder of the metal and glass according to the present invention, it is possible to prepare a stable paste, and the metal and glass components are uniformly mixed to form an electrode. The resulting film is very dense, has excellent adhesive properties with the substrate, and can lower the resistivity of the electrode. Therefore, the film can be efficiently used in various fields such as displays, capacitors, solar cells, electronic tags, and illumination electrodes requiring low-resistance metal electrodes. Can be used.

Hereinafter, the present invention will be described in detail.

This invention (1) containing the structural component of a metal and glass Dissolving the precursor material in distilled water, alcohol, acid or the like to prepare a precursor solution of 0.02 to 3 M; (2) injecting the precursor solution into a spray apparatus to generate droplets of 0.1 to 100 μm in diameter; And (3) preparing the spherical metal and glass composite powder whose composition is controlled by a flame spray pyrolysis process by introducing the generated droplets into a diffusion flame reactor maintained at a constant temperature. It provides a method for producing a powder.

In the present invention, the metal and glass are preferably mixed in the range of 90 to 99.5% by weight and 0.5 to 10% by weight with respect to the total weight, more preferably 94 to 99% by weight of metal and 1 to 6% by weight of glass. It is preferable to mix in the range of weight%.

In the present invention, when the glass is mixed less than 0.5% by weight, there is a problem of lowering the sintering characteristics of the metal powder due to the lack of the glass component, it does not contribute to improving the adhesive properties with the substrate. On the other hand, when the glass exceeds 10% by weight, yellowing may occur when the glass component reacts with the metal and the substrate during firing, and the excessive electrical component of the glass may cause the metal to lose electrical conductivity. .

In addition, the metal and glass in the present invention can be used in the form of a precursor containing a component of the metal and glass, It is preferable to use salts such as acetate, nitrate, chloride, hydrate, oxide, etc., which are easily soluble in water or alcohol, and the optimum composition combinations with each other. Can be derived.

More preferably, the metal is silver oxide, gold oxide, copper oxide, nickel oxide, aluminum oxide, magnesium oxide, and magnesium oxide. Palladium oxide (palladium oxide) is preferably made of one or more alloys selected from the group consisting of .

In addition, the glass may be a glass of various compositions commonly used in the industry. Preferably lead oxide (PbO) 40 to 80% by weight, boron oxide (B ₂ O ₃ ) 1 to 20% by weight, silicon oxide (SiO ₂ ) 3 to 20% by weight, aluminum oxide (Al ₂ O ₃ ) 1 to 10 wt%, barium oxide (BaO) 1-10 wt%, zinc oxide (ZnO) 0-15 wt%, titanium oxide (TiO ₂ ) 0-20 wt%, bismuth oxide (Bi ₂ O ₃ ) 0-10 wt% 40 to 90% by weight of bismuth oxide, 0 to 30% by weight of boron oxide, 5 to 30% by weight of zinc oxide, and additives of silicon oxide, barium oxide, aluminum oxide, sodium oxide (Na ₂ O) The lead-free glass is preferably composed of a composition of 0 to 10% by weight. In particular, when using lead-free glass, more preferably 50 to 80% by weight of bismuth oxide, 5 to 10% by weight of boron oxide, 5 to 15% by weight of zinc oxide, and silicon oxide, barium oxide, aluminum oxide, oxide as additives Sodium (Na ₂ O) is preferably composed of a composition of 0 to 5% by weight, respectively. Further, the glass composition of the PbO-SiO ₂ -B ₂ O ₃ system is also applicable.

At this time, the precursor solution of the metal or / and glass is preferably prepared in a concentration of 0.02 ~ 3M, when the concentration of the precursor solution is less than the above range, the effect of reducing the average particle diameter of the nanocomposite powder of the metal and glass to be synthesized However, there is a problem that the productivity of the powder is lowered because the concentration of the solution is low, on the contrary, when the concentration of the solution exceeds the above range, there is a problem that the particle diameter becomes larger than necessary.

In addition, in the present invention, the spraying apparatus for spraying the complex powder precursor solution of the metal and glass using the spraying apparatus as an ultrasonic spraying device, air nozzle spraying device, ultrasonic nozzle spraying device, filter expansion droplet generator (filter expansion) Various devices such as aerosol generator (FEAG), or disk type droplet generator can be used. In particular, ultrasonic nebulizers are most preferred for the production of ultra-fine powders of several microns in size for use in displays and capacitors.

At this time, if the droplet size is less than 0.1 μm, the particle size of the nanocomposite powder of the metal and glass is reduced, but the productivity of the powder is reduced due to the decrease in the amount of droplets produced, and the powder is produced when the size of the droplet exceeds 100 μm. The particle diameter of can be larger than necessary to tens of micrometers.

In addition, the present invention is possible to manufacture the nano-composite powder of metal and glass through the process of drying, decomposition, evaporation, nucleation, particle growth and quenching the droplets in the diffusion flame reactor. That is, the nanoparticle powder of the metal and glass can be prepared in the reactor by dropping the droplet to the nozzle generating the diffusion flame, wherein the diffusion flame is generated as the fuel and oxygen diffuse out of the nozzle. Propane gas, hydrogen gas, or the like may be used as the fuel source, and oxygen or air may be used as the oxygen source.

In the flame spray pyrolysis process according to the present invention, fuel, oxidant, carrier gas type and flow rate are important variables, and in order to obtain a nanocomposite powder in a given reactor, a suitable temperature at which dry decomposition is sufficiently required is required. In other words, the residence time in the reactor and the size and temperature of the diffusion flame can be controlled by controlling the type and flow rate of the fuel source, the flow rate of the oxygen source and the ratio with the fuel source, the type and flow rate of the oxidant and carrier gas, When it is necessary to control the oxygen concentration of the metal and glass nanocomposite powders in order to increase the electrical properties of the nitrogen, to maintain an inert atmosphere or a reducing atmosphere, nitrogen (N ₂ ), argon (Ar) or hydrogen (H ₂ ) / nitrogen Mixed gas such as hydrogen and argon may be used as the carrier gas.

In the present invention, in order to prepare a nano-sized metal and glass composite powder by the flame spray pyrolysis process, the complete vaporization of the precursor powder constituting the composite powder is required, and the complete vaporization of the precursor powder is performed in a reactor temperature range of 800 to 3,000 ° C. If the reactor temperature is less than 800 ℃, the complete vaporization of the components constituting the metal and glass does not occur and may not form the nanoparticles of the powder, if the reactor temperature exceeds 3,000 ℃ The composition of the powder may change due to volatilization of the components constituting the metal and glass. In addition, the residence time of the carrier gas in the reactor is preferably maintained at 0.1 to 30 seconds.

However, the optimum flame temperature may vary depending on the composition of the Bi-based and Pb-based glass powders to be prepared, and may also vary depending on the type, concentration, and solvent of the precursor powder. In this case, it is important to completely vaporize the precursor powder constituting the composite powder to prepare a nano-sized metal and glass composite powder through the flame spray pyrolysis process, so that the temperature of the precursor powder is appropriately adjusted according to the precursor composition. Should remain different.

The present invention also provides a metal glass nanocomposite powder.

The metal glass nanocomposite powder is preferably prepared by applying a flame spray pyrolysis process, and more preferably, according to the above method.

In the metal glass nanocomposite powder according to the present invention, the metal and the glass are preferably mixed in the range of 90 to 99.5% by weight and 0.5 to 10% by weight with respect to the total weight. In addition, the metal glass nanocomposite powder of the present invention has a spherical shape, and size control of several nanometers to several hundred nanometers can be performed from 10 nm to 300 nm depending on the change in the concentration of the spray solution and the process conditions.

The present invention also provides an electrode paste composition further comprising an organic component in the metal glass nanocomposite powder prepared by the above method.

The metal glass nanocomposite powder, which is an inorganic component, is preferably added in the range of 25 to 70% by weight of the total weight, and more preferably in the range of 40 to 60% by weight. When the content of the metal and glass nanocomposite powder is less than 25% by weight in manufacturing the electrode paste, the thickness of the electrode formed per print decreases, thereby increasing the line resistance of the electrode for the plasma display back panel, and the content of the metal and glass nanocomposite powder. When it exceeds 70% by weight, the viscosity of the paste is so high that it becomes difficult to form a conductive film.

In addition, the organic component may include a photosensitive component including a photosensitive unit, a photosensitive oligomer or a photosensitive polymer, preferably a binder, a photopolymerization initiator, an ultraviolet absorber, a sensitizer, a sensitizer, a plasticizer, a thickener, an antioxidant, It may further include additive components such as dispersants, organic or inorganic precipitation inhibitors or leveling agents.

The present invention also provides a patterned electrode prepared by applying the electrode paste composition on a substrate and then drying.

In the present invention, the electrode paste is printed by a screen printing method, an offset or an inkjet method, and the like is patterned through a photosensitive process or produced in the form of a green sheet. In addition, the thickness of the electrode paste applied on the substrate is preferably 1 to 30㎛, and after the coating is preferably baked in the range of 300 to 900 ℃ through a drying process.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these examples are for illustrative purposes only and that the scope of the present invention is not construed as being limited by these examples.

Example 1 Preparation of Nano Metal Powders

In the present invention, the nano-sized metal powder was synthesized by applying the flame spray pyrolysis process under various synthesis conditions.

The flame spray pyrolysis process according to the present invention is classified into a droplet generation unit, a reaction unit in which the resulting droplets form glass by a high temperature flame, and a bag filter for collecting the generated particles. The droplet generator used an industrial humidifier operating at a frequency of 1.7 MHz, and oxygen was used as a carrier gas to smoothly transport a large amount of droplets generated by six ultrasonic vibrators into the reactor.

Specifically, containing a metal component The precursor solution was generated as droplets having a size of several μm using an ultrasonic atomizer, and oxygen gas having a flow rate of 20 l / min. Was used as a carrier gas, and the droplets were introduced into the diffusion flame through a nozzle to synthesize metal powder. .

At this time, propane and oxygen gas were used as fuel gas and oxidizing gas to form a flame, respectively, and each flow rate was 5 L / min. And 40 L / min. In addition, the spray solution was prepared by distilled water with a total concentration of nitrates of 0.5M of the components constituting the composite powder of metal and / or glass.

1 is an electron micrograph of a metal powder prepared according to the present invention.

Example 2 Preparation of Metal and Bi-based Glass Nanocomposite Powders (1)

Metal and Bi-based glass nanocomposite powders were prepared under the same flame spray pyrolysis process as in Example 1, but Bi-based glass was 78 wt% of Bi ₂ O ₃ , 5 wt% of B ₂ O ₃ , and 15 wt% of ZnO, 1 wt% SiO ₂ , 0.45 wt% BaO, 0.5 wt% Al ₂ O ₃ and 0.05 wt% Na ₂ O were used. The nano-metal powder and Bi-based glass prepared in Example 1 were each 97 Volume% and 3% by weight were added (see FIG. 2).

Example 3 Preparation of Metal and Bi-based Glass Nanocomposite Powders (2)

Metal and Bi-based glass nanocomposite powders were prepared under the same conditions as in Example 2, but 78 wt% of Bi ₂ O ₃ , 5 wt% of B ₂ O ₃ , 15 wt% of ZnO, 1 wt% of SiO ₂ , and BaO of 0.45. 10 wt% of a Bi-based glass composed of 0.5 wt% of Al ₂ O ₃ and 0.05 wt% of Na ₂ O was added (see FIG. 3).

Example 4 Preparation of Metal and Pb-based Glass Nanocomposite Powders

Metal and Pb-based glass nanocomposite powder were prepared under the same flame spray pyrolysis process as in Example 1, but Pb-based glass was composed of 77 wt% PbO, 3 wt% B ₂ O ₃ , 2.2 wt% ZnO, and SiO ₂ 14.5. Wt%, Al ₂ O ₃ 2.8% by weight and TiO ₂ was composed of 0.5% by weight, the nano-metal powder prepared in Example 1 and Bi-based glass were added by 97% by weight and 3% by weight, respectively ( See FIG. 4).

Example 5 Characterization of Metal Glass Nanocomposite Powders

The metal and glass nanocomposite powders prepared in Examples 1 to 3 were mixed with an organic binder composed of ethyl cellulose, alpha-terpineol, and butyl carbitol acetate. Pastes in the range of 30,000 to 100,000 centipoise were prepared to impart fluidity suitable for application, and the desired electrode pattern was formed on the glass substrate by screen printing. After drying, baking was carried out at a low temperature in the range of 350 to 550 ° C. for 10 minutes to form an electrode.

Characterization of the paste was prepared with the same composition to compare the state after printing drying and firing (see FIGS. 5, 6 and 7).

As can be seen in FIGS. 5, 6, and 7 showing the surface characteristics of the electrode obtained at the firing temperature of 400 ° C. when the glass components are 0, 3, and 10 wt%, respectively, as the glass component increases, the sintering characteristics of the electrode are increased. The improvement was confirmed to have a dense membrane characteristic.

In addition, 3 weight% of glass components were added, and the cut cross section of the electrode (refer FIG. 6) obtained at the baking temperature of 400 degreeC was observed with the electron microscope, and is shown in FIG. As a result, as shown in FIG. 8, it was confirmed that the adhesion property between the metal electrode and the glass substrate was very excellent.

Moreover, the film was firmly adhered to the substrate without peeling phenomenon, which is because the glass components constituting the nanocomposite powder of metal and glass move under the electrode during firing and react with the glass substrate to bond the metal electrode to the glass substrate. It is believed to improve the

In addition, as a result of measuring the resistivity of the conductive films according to the present invention by a four-point electric conductivity measuring device (CMT-SR 1000N, Advanced Instrument Technology), relatively low values of 8, 4.2, and 5 µΩ · cm, respectively, were shown (FIG. 11). Reference).

Comparative example. Characterization of Metal Powders Without Glass Components

A micron-sized pure metal powder containing no glass component was synthesized by spray pyrolysis (reactor temperature: 1,000 ° C.), and a paste was prepared under the same conditions as in Example 5 to prepare an electrode that was subjected to baking after screen printing. It was.

As a result of observing the cut surface of the prepared electrode, the surface of the electrode obtained from the metal powder containing no glass component exhibited a very porous surface property after the firing at 400 ℃ due to poor plasticity properties (see Fig. 9), As shown in FIG. 10, it was confirmed that the peeling phenomenon occurred between the glass substrate and the electrode. In addition, the specific resistance value of the metal electrode obtained from the micron-sized pure metal powder was 24 µΩ · cm, which was very high when compared with the electrode obtained from the nanocomposite powder of the metal and glass of the present invention (see FIG. 11).

As described above, specific portions of the contents of the present invention have been described in detail, and for those skilled in the art, these specific techniques are merely preferred embodiments, and the scope of the present invention is not limited thereto. Will be obvious. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

1 is an electron micrograph of the nano-metal powder prepared by the flame spray pyrolysis process according to the present invention.

2 is an electron micrograph of a metal glass nanocomposite powder containing 3 wt% of a glass component prepared according to one embodiment of the present invention.

3 is an electron micrograph of a metal glass nanocomposite powder containing 10 wt% of a glass component prepared according to another embodiment of the present invention.

4 is an electron micrograph of a metal glass nanocomposite powder composed of a Pb-based glass component prepared according to another embodiment of the present invention.

FIG. 5 is an electron micrograph observing film characteristics of an electrode made of the metal nanopowder of FIG. 1.

FIG. 6 is an electron microscope photograph of film characteristics of an electrode prepared from the metal glass nanocomposite powder of FIG. 2.

FIG. 7 is an electron microscope photograph of film characteristics of an electrode made of the metal glass nanocomposite powder of FIG. 3.

FIG. 8 is an electron microscope photograph of a cut section of the electrode of FIG. 6.

9 is an electron micrograph of the film characteristics of the electrode made of a pure metal powder of micron size does not contain a glass component prepared according to a comparative example of the present invention.

FIG. 10 is an electron microscope photograph of a cut section of the electrode of FIG. 9. FIG.

11 is a graph illustrating the electrical characteristics of FIGS. 5, 6, and 9.

Claims (19)

(1) dissolving a precursor material containing a constituent of metal and glass in distilled water or alcohol to prepare a precursor solution of 0.02 to 3 M; (2) injecting the precursor solution into a spray apparatus to generate droplets of 0.1 to 100 μm in diameter; And (3) preparing the spherical metal and glass composite powder whose composition is controlled by the flame spray pyrolysis process by introducing the generated droplets into a diffusion flame reactor. The method of claim 1, The metal and glass are mixed in the range of 90 to 99.5% by weight and 0.5 to 10% by weight based on the total weight, respectively. The method of claim 1, The precursor material containing the constituents of the metal and glass is at least one member selected from the group consisting of acetate, nitrate, chloride, hydrate, and oxide. Manufacturing method. The method of claim 1, The metal may be silver oxide, gold oxide, copper oxide, nickel oxide, aluminum oxide, magnesium oxide, and palladium oxide. Production method characterized in that at least one selected from the group consisting of. The method of claim 1, The glass is 40 to 80% by weight of lead oxide (PbO), 1 to 20% by weight of boron oxide (B ₂ O ₃ ), 3 to 20% by weight of silica (SiO ₂ ), 1 to 10% by weight of alumina (Al ₂ O ₃ ) %, 1-10 wt% of barium oxide (BaO), 0-15 wt% of zinc oxide (ZnO), 0-20 wt% of titania (TiO ₂ ), 0-10 wt% of bismuth oxide (Bi ₂ O ₃ ) Manufacturing method characterized in that consisting of. The method of claim 1, The glass is 40 to 90% by weight of bismuth oxide, 0 to 30% by weight of boron oxide, 5 to 30% by weight of zinc oxide, and 0 to 10% by weight of silica, barium oxide, alumina and sodium oxide (Na ₂ O) as additives, respectively. Method for producing a lead-free glass composition consisting of%. The method of claim 1, The glass is a manufacturing method, characterized in that consisting of a glass composition of PbO-SiO ₂ -B ₂ O ₃ system. The method of claim 1, The spraying apparatus is selected from an ultrasonic atomizer, an air nozzle sprayer, an ultrasonic nozzle sprayer, a filter expansion aerosol generator (FEAG), or a disk type droplet generator. The method of claim 1, The reactor is characterized in that the temperature is maintained in the range of 800 to 3,000 ℃. Metal glass nanocomposite powder prepared by the method of claim 1. The method of claim 10, The powder is a metal glass nanocomposite powder, characterized in that the metal and glass are mixed in the range of 90 to 99.5% by weight and 0.5 to 10% by weight relative to the total weight. The method of claim 10, The powder is a metal glass nanocomposite powder, characterized in that having a spherical size of 10 to 300nm. An electrode paste composition further comprising an organic component in the metal glass nanocomposite powder prepared by the method of claim 10. The method of claim 13, The composition is an electrode paste composition, characterized in that the metal glass nanocomposite powder is added in the range of 25 to 70% by weight relative to the total weight. The method of claim 13, The organic component is an electrode paste composition, characterized in that at least one selected from binders, photopolymerization initiators, ultraviolet absorbers, sensitizers, sensitizers, plasticizers, thickeners, antioxidants, dispersants, organic or inorganic precipitation inhibitors and leveling agents. A patterned electrode prepared by applying the electrode paste composition of claim 13 onto a substrate and then drying. The method of claim 16, The electrode paste composition is printed by screen printing, offset or inkjet method, the patterned electrode, characterized in that it is patterned through a photosensitive process or produced in the form of a green sheet. The method of claim 16, Patterned electrode, characterized in that the thickness of the electrode paste applied on the substrate is 1 to 30㎛. The method of claim 16, Patterned electrode, characterized in that the firing in the range of 300 to 900 ℃ after the electrode paste coating and drying process.

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