KR101046629B1 - Spherical Composite Powder of Ag and Glass - Google Patents

Abstract

The present invention relates to composite powder synthesis of silver and glass for conductive pastes used in various fields such as displays and capacitors.

Silver and Glass Composite, Powder, Conductive, Paste

Description

Spherical shape composite powders of Ag and glass

The present invention relates to composite powder synthesis of silver and glass for conductive pastes used in various fields such as displays and capacitors.

In general, the conductive paste composition is formed by mixing a conductive metal powder, a glass frit and an organic vehicle, and is applied to various components to be electrically connected by a screen printing method or a dipping method, and then dried and sintered. It will play a role. As the conductive metal powder, silver, copper, nickel, and the like having excellent electrical conductivity are used, and the glass frit provides bonding strength after firing between the conductive metal powder and the applied part.

Since silver powder mainly used as an electrode material was synthesized by a gas phase method or a liquid phase method, most of them have a spherical shape. Currently, glass frit powder synthesis technology uses a conventional melting method. Under the existing process, the molten raw material was quenched into a flake form, and then glass frit powder having a desired particle size was synthesized through various milling and classification processes. In the above technique, several steps of milling and classification processes are essential, which has disadvantages such as poor performance of the glass frit powder, a large number of unit processes, and a yield reduction for obtaining a powder having a desired particle size. Although many disadvantages have been overcome at present, there are still disadvantages that have to be taken, and much effort has been put into paste manufacturing technology to overcome the problem of dispersibility.

As an electrode material, silver powders have various sizes ranging from tens of nanometers to several microns. On the other hand, the conventional method is difficult to nano-size the glass powder. Therefore, different size and shape characteristics of silver and glass powders make it difficult to prepare a stable paste.

The present invention solves the above problems, and the object of the present invention is to solve the non-uniformity and paste instability that may occur in the process of pasting and mixing the existing silver powder and glass frit at the same time Is to provide a way.

Another object of the present invention is to provide an excellent electrode material.

In order to achieve the above object, the present invention provides a composite powder, characterized in that, in the silver and glass composite powder, the silver component is 90 to 99.5% by weight of the powder, and the glass component is 0.5 to 10% by weight.

In a preferred embodiment of the present invention, the glass component is preferably 1 to 4.5% by weight, more preferably 1 to 3% by weight, but is not limited thereto.

In a preferred embodiment of the present invention, the powder is preferably in the shape of a sphere.

In addition, in one embodiment of the present invention, the glass composition is lead oxide (PbO) 40 to 80% by weight, boron oxide (B ₂ O ₃ ) 1 to 20% by weight, silica (SiO ₂ ) 3 to 20 % By weight, 1-10% by weight of alumina (Al ₂ O ₃ ), 0-10% by weight of barium oxide (BaO), 0-15% by weight of zinc oxide (ZnO), 0-2 by weight of titania (TiO ₂ ) Wt%, and bismuth oxide (Bi ₂ O ₃ ) is preferably from 0 to 10% by weight,

In another embodiment of the present invention, the glass composition is 40 to 90% by weight of bismuth oxide (Bi ₂ O ₃ ), 0 to 30% by weight of boron oxide (B ₂ O ₃ ), zinc oxide (ZnO) is 5 To 30 wt% and an additive, preferably 50 to 80 wt% of bismuth oxide (Bi ₂ O ₃ ); Boron oxide (B ₂ O ₃ ) in an amount of 5 to 15 wt%; Zinc oxide (ZnO) is 5 to 15% by weight; More preferably, the additive contains 0 to 5% by weight of silica (SiO ₂ ), barium oxide (BaO), alumina (Al ₂ O ₃ ), and sodium oxide (Na ₂ O), but is not limited thereto.

The present invention also provides an electrode paste containing the composite powder of the present invention.

In a preferred embodiment of the present invention, the content of the composite powder of the electrode paste is preferably 25 to 55% by weight, but is not limited thereto.

In another preferred embodiment of the present invention, the average particle diameter of the composite powder is preferably 0.1 ~ 10㎛, but is not limited thereto.

Also,

(a) obtaining a composite powder precursor solution of silver and glass

(b) injecting the precursor solution into a spray device to generate droplets; And

(C) it provides a method for producing a composite powder of silver and glass comprising the step of introducing the generated droplets into the reactor.

In one embodiment of the present invention, the precursor solution is preferably obtained by dissolving the composite powder precursor materials of silver and glass in water, alcohol or acid.

In a preferred embodiment of the present invention, the precursor material is one or more materials selected from the group consisting of acetate, nitrate, chloride, hydrate, and oxide salts. Preferred but not limited to this.

In a preferred embodiment of the present invention, the concentration of the precursor solution is preferably 0.02 to 3 M, but is not limited thereto.

In another preferred embodiment of the present invention, the diameter of the droplet is preferably 0.1 to 100 ㎛ diameter, but is not limited thereto.

In a preferred embodiment of the present invention, the temperature in the reactor is preferably 600 ~ 1500 ℃ but is not limited thereto.

In one embodiment of the present invention, the atomizer is preferably an ultrasonic atomizer, an air nozzle atomizer, an ultrasonic nozzle atomizer, a disk type droplet generator or filter expansion droplet generator.

Hereinafter, the present invention will be described.

The present invention relates to the direct production of a composite powder of silver and glass that can be directly applied for the electrode. The present invention aims to provide a new technique for synthesizing a composite powder of silver and glass as a method to simultaneously solve the unevenness and paste instability that may occur in the process of mixing the existing silver powder and glass frit. Under the spray pyrolysis process for synthesizing spherical silver powder, spherical silver and glass composite powders were synthesized by simultaneously dissolving and applying constituents of silver and glass frit in a spray solution. The composite powder of silver and glass synthesized by the spray pyrolysis process had excellent sintering properties and excellent electrical properties during the firing process by the conventional method.

In the present invention, the composite powder of silver and glass was synthesized by applying an economical spray pyrolysis process with a small number of unit processes in a continuous process. In the present invention to provide a spherical composite of silver and glass for the first time to provide a new synthesis technology and new material technology at the same time. In addition, the superiority of the sintering and electrical properties of the silver and glass composite powders between tens of nanometers and several microns synthesized in a large amount by spray pyrolysis process is compared with the conventional silver electrode paste. It was intended to show the superiority of the composite powder as an electrode material.

In the composite powder synthesis of silver and glass of the present invention, the silver component is preferably 90 to 99.5% by weight of the powder, and the glass component is preferably 0.5 to 10% by weight. If the glass component is 0.5 wt% or less, there is a problem of deteriorating the sintering characteristics of the silver powder due to the lack of the glass component, and also does not contribute to the improvement of adhesive properties with the substrate. On the other hand, when the glass component is more than 10% by weight, a yellowing phenomenon may occur in which the glass component reacts with silver and the substrate during firing, and color change may occur, and the electrical conductivity of silver may decrease due to excessive glass component.

  The composite powder of silver and glass synthesized according to the present invention has a spherical shape, and can be controlled in size from several tens of nanometers to several microns according to a change in concentration of the spray solution. In addition, it is possible to control the phase separation form of the silver and glass components by changing the synthesis conditions. For example, when the reactor temperature is higher than about 1000 ° C., melting of silver and glass components occurs under spray pyrolysis. Therefore, phase separation between silver and glass components having different densities occurs. Since quenching occurs in a phase-separated state between the silver and glass components, the silver and glass components are separated to have a coated form. On the other hand, in the case where the reactor temperature of the spray pyrolysis process is lower than 600 ° C., complete phase separation between the two components does not occur because complete melting of the components constituting silver and glass does not occur. Therefore, the silver and glass components are mixed with each other. Of course, the reactor temperature at which the structural change of the composite powder of silver and glass occurs depends on the flow rate of the carrier gas, the type of carrier gas, and the like.

In the composite powder of silver and glass of the present invention, the glass is generally applicable to glass of various compositions used in the industry. Examples include lead oxide (PbO) 40 to 80% by weight, boron oxide (B ₂ O ₃ ) 1 to 20% by weight, silica (SiO ₂ ) 3 to 20% by weight, alumina (Al ₂ O ₃ ) 1 to 10% by weight, 0-10% by weight of barium oxide (BaO), 0-15% by weight of zinc oxide (ZnO), 0-2% by weight of titania (TiO ₂ ), 0 of bismuth oxide (Bi ₂ O ₃ ) Glass of from 10% by weight to composition can be used. In addition, as a lead-free glass, bismuth oxide (Bi ₂ O ₃ ) is preferably 40 to 90% by weight, preferably 50 to 80% by weight, and boron oxide (B ₂ O ₃ ) is 0 to 30% by weight, preferably 5 to 15% by weight, zinc oxide (ZnO) is 5 to 30% by weight, preferably 5 to 15% by weight, silica (SiO ₂ ), barium oxide (BaO), alumina (Al ₂ O ₃ ), sodium oxide as an additive (Na ₂ O) can each be used in an amount ranging from 0 to 10% by weight, preferably in the range from 0 to 5% by weight.

In the spray pyrolysis process of the present invention, the reactor temperature, the flow rate of the carrier gas, the reactor size and the like serve as important parameters in the synthesis of the silver and glass composite powder. Sufficient residence time in the reactor must be sufficient to obtain a compact composite powder at a given reactor size (reactor internal diameter and length). Therefore, when the reactor temperature is high, the residence time can be reduced, and when the reactor temperature is low, the residence time in the reactor can be increased by reducing the flow rate of the carrier gas. In addition, since silver powder can be easily synthesized by spray pyrolysis in air, the type of carrier gas is not greatly limited. However, when it is necessary to control the oxygen concentration of the silver and glass composite powder in order to improve the electrical properties of the powder, a mixed gas such as nitrogen, argon or hydrogen / nitrogen, hydrogen / argon may be used to maintain an inert atmosphere or a reducing atmosphere. It can also be used as a carrier gas.

The composite powder of silver and glass synthesized by the present invention is prepared in the form of a paste mixed with an organic compound and applied to a printing process. The paste is printed by a process such as screen printing and a pattern is formed through a photosensitive process. The organic component included in the electrode paste may include a photosensitive component including a photosensitive unit, a photosensitive oligomer, or a photosensitive polymer, and preferably, a binder, a photopolymerization initiator, a UV absorber, a sensitizer, a sensitizer, a plasticizer, a thickener, an oxidation agent. It may further include additive components such as inhibitors, dispersants, organic or inorganic precipitation inhibitors or leveling agents. At this time, it is preferable that the inorganic component, which is a silver and glass composite, in the mixing of the organic component and the inorganic component that is burned and evaporated upon firing is 25 to 55% by weight.

In addition, an electrode structure may be directly patterned by offset and inkjet, or may be manufactured in the form of a green sheet and used to form an electrode.

Hereinafter, the present invention will be described in more detail in order to enable those skilled in the art to more easily implement the present invention.

  The present invention is a step of preparing a precursor solution of 0.02 to 3 M by dissolving a precursor material constituting the composition of silver and glass in distilled water or alcohol;

In this process, when the concentration of the solution is 0.02 M or less, the average particle diameter of the composite powder of silver and glass to be synthesized is reduced, but the productivity of the powder is lowered because the concentration of the solution is low. On the contrary, when the concentration of the solution is 3 M or more, there is a problem that the particle size becomes larger than necessary.

Injecting the precursor solution into a spray device to generate droplets having a diameter of 0.1 to 100 µm;

In the case of droplets having a diameter of 0.1 micron or less in this step, the particle diameter of the composite powder of silver and glass is reduced, but the amount of droplets is reduced, thereby reducing the productivity of the powder. In addition, if the droplet size is 100 microns or more, the particle size of the synthesized powder has a problem that it becomes larger than necessary to several tens of microns.

Preparing the composite powder of silver and glass by introducing the generated droplets into a reactor (600-1500 ° C.);

In the case where the temperature of the reactor is 600 ° C. or less, complete decomposition of silver and the components constituting the glass may not occur, and the components constituting the glass may have a crystalline phase without forming a glass phase. When the temperature of the reactor is 1500 ° C. or higher, volatilization of the components constituting silver and glass may occur to increase the particle size distribution of the powders, and the composition of the powder may also be changed by volatilization.

The method for preparing a composite powder of fine spherical silver and glass according to the present invention will be described in more detail by dividing each process as follows.

1) First step: obtaining a composite powder precursor solution of silver and glass

In powder synthesis, the silver component is 90 to 99.5% by weight of the powder, and the glass component is preferably 0.5 to 10% by weight. If the glass component is 0.5 wt% or less, there is a problem of deteriorating the sintering characteristics of the silver powder due to the lack of the glass component, and also does not contribute to the improvement of adhesive properties with the substrate. On the other hand, when the glass component is more than 10% by weight, a yellowing phenomenon may occur in which the glass component reacts with silver and the substrate during firing, and color change may occur, and the electrical conductivity of silver may decrease due to excessive glass component. Preferably from 1 to 3% by weight of glass component is appropriate. In order to obtain a composite powder of silver and glass, the present invention is used by dissolving precursor materials containing a desired component of silver and glass in water, alcohol, acid, or the like. As materials, salts such as acetate, nitrate, chloride, hydrate, oxide, etc., which are easily dissolved in a solvent such as water or alcohol, can be used. You can also derive the composition combination of.

The composition of the glass is 40 to 90% by weight of bismuth oxide (Bi ₂ O ₃ ) as a glass forming agent, the preferred amount is 50 to 80% by weight, boron oxide (B ₂ O ₃ ) is 0 to 30% by weight, preferably 5 to 15% by weight, zinc oxide (ZnO) is 5 to 30% by weight, preferably 5 to 15% by weight, silicon oxide (SiO ₂ ), barium oxide (BaO), aluminum oxide (Al ₂ O ₃ ) as an additive ) And sodium oxide (Na ₂ O) are each used in an amount ranging from 0 to 10% by weight, preferably in the range from 0 to 5% by weight. In addition, the glass composition of the PbO-SiO ₂ -B ₂ O ₃ system is also applicable.

2) second process: spraying of droplets

Next, the process of spraying the glass frit powder precursor solution into the droplets using a spray device.

In this case, as the spray device, an ultrasonic spray device, an air nozzle spray device, an ultrasonic nozzle spray device, a filter expansion aerosol generator (FEAG), a disk type droplet generator, or the like may be used as the spray device. have. Ultrasonic nebulizers are most suitable for the synthesis of ultrafine powders, especially for use in displays and capacitors.

3) 3rd process: production | generation of the composite powder of silver and glass

A droplet of the composition is converted into a composite powder of silver and glass in a hot tubular reactor. At this time, the temperature of the electric furnace is preferably 600 ~ 1500 ℃ for drying the precursor materials. In this high temperature reactor, although the residence time is short, by heating, the metal precursor materials contained in the reaction solution are decomposed and converted into silver and glass, and a composite powder of silver and glass is obtained. The composite powder of silver and glass obtained through the spray pyrolysis process melts its components almost simultaneously with drying and decomposition of the precursor materials when the reactor temperature and the flow rate of the carrier gas are appropriate, and the liquid precursor is spherical to reduce the degree of freedom. Since a single powder is formed in one droplet, a composite powder of silver and glass in a submicron unit is synthesized without additional milling and classification.

4) 4th process: formation of a conductive film

A paste using an organic binder including a dispersant and the like and a composite powder of silver and glass synthesized was prepared. It is preferable that the inorganic component which is silver and glass composite at the time of paste preparation is 25 to 55 weight%. In the electrode paste, the composite powder of silver and glass is made of spherical particles produced by spray pyrolysis, and has an average particle diameter of 0.1 to 10 µm. If the average particle diameter of the composite powder powder of silver and glass is 0.1 μm or less, it is difficult to form a paste, and if it is 10 μm or more, it is difficult to densify sufficiently during the formation of the conductive film, short circuit of the conductive film due to pores, and electrical resistivity becomes high. In addition, when the content of the composite powder of silver and glass is 25 wt% or less, 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 composite powder of silver and glass is 55 wt. If it is% or more, the viscosity of the said paste is too high and it becomes difficult to shape an electrically conductive film.

The present invention provides a novel technology and composite powder for synthesizing a large amount of spherical ultrafine silver and glass composite powder. The particles synthesized by the spray pyrolysis process have a uniform particle size distribution and maintain a perfect spherical shape. In addition, the silver and glass composite powder can be manufactured in various structures such as a structure in which the glass component surrounds the silver and a glass component in the silver powder due to changes in the manufacturing temperature and the carrier gas flow rate. In the case of making a paste using the silver and glass composite powder, since a phase separation of silver and glass does not occur, stable paste production is possible. In addition, since the silver and glass components are uniformly mixed, the film obtained after electrode formation is very dense, and the adhesion property with the substrate is also excellent. In addition, because the film is dense, the electrode specific value can also be very low. The composite powder of silver and glass synthesized by the spray pyrolysis process will be efficiently applied to various fields such as a display and a capacitor requiring a low resistance silver electrode.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are only intended to explain the present invention more specifically, and the scope of the present invention according to the gist of the present invention to these examples. It will be apparent to one of ordinary skill in the art that the present invention is not limited thereto.

Example 1 Composite Powder Synthesis of Fine Spherical Silver and Glass

Glass frit powder was synthesized by spray pyrolysis process under various synthesis conditions. The spray pyrolysis process is divided into a droplet generating unit, a reaction unit in which the generated droplets react with high-temperature energy, and a bag filter for collecting the generated particles. The droplet generator used an industrial humidifier operating at a frequency of 1.7 MHz. Air was used as a carrier gas to smoothly transport a large amount of droplets generated by six ultrasonic vibrators, and the flow rate was maintained at 20 l / min. The reaction part was a high purity alumina tube having a length of 1000 mm and an inner diameter of 50 mm. This embodiment is in the synthesis and the composition of the glass of the composite powder of the glass is 78 wt.% Bi ₂ O ₃ -5 wt.% B ₂ O ₃ -15 wt.% ZnO -1 amount of% SiO _{2 -} 0.45 wt.% BaO - 0.5 wt% Al ₂ O ₃ -0.05 wt% Na ₂ O. In the powder synthesis, the silver component was 97% by weight of the powder and the glass component was kept at 3% by weight. The temperature of the reaction section where a large amount of droplets generated by the ultrasonic spray device is dried, precipitated, pyrolyzed and melted was changed from 1000 ° C to 1300 ° C. The spray solution maintained the total concentration of nitrates of the components constituting the composite powder of silver and glass in distilled water at 0.5 M.

1 and 2 show electron micrographs of the composite powder of silver and glass synthesized when the reactor temperature is 1000 and 1300 ° C., respectively. Regardless of the reactor temperature, the synthesized powder has a spherical shape and an average size of 0.787 and 0.748 microns, respectively. Figure 3 shows the crystal structure of the composite powder of silver and glass synthesized when the reactor temperature is 1000 and 1300 ℃, respectively. The powder synthesized in the XRD pattern analysis shows the crystal structure of pure Ag. The crystal structure of the components constituting the glass did not appear. Therefore, it can be seen that the synthesized powder is composed of a complex structure of silver and glass.

Example 2: Change of amount of glass in the synthesis of composite powder of fine spherical silver and glass

Example 1 and the production conditions are the same, but the glass component in the powder synthesis was changed to 1 and 5% by weight of the powder. The reactor temperature for powder synthesis was 1300 ° C. The weight percent of the glass component did not change the shape or crystal structure of the powder synthesized by the spray pyrolysis process.

Example 3: Evaluation of the electrical properties of the composite powder of silver and glass synthesized by spray pyrolysis

In order to provide a fluidity suitable for application by mixing with the composite powder of silver and glass obtained in Examples 1 and 2 and the organic binder, a paste in the range of 30,000 to 100,000 centipoise is made, and a desired electrode pattern is formed on the glass substrate by screen printing. After forming, and dried for 10 minutes at a low temperature in the range of 450 to 550 ℃ to form an electrode. The evaluation method produced the paste with the same composition, and compared the state after printing drying and baking.

4, 5 and 6 show the surface characteristics of the electrode obtained at the firing temperature of 550 ° C. when the glass components were 1, 3 and 5% by weight, respectively. It can be seen that as the glass component increases, the sintering characteristic of the silver electrode is improved to have a dense film characteristic, and the secondary phase due to phase separation is observed at 5 wt% of the glass component. 7 is an electron micrograph showing a cut section of the sample shown in FIG. It can be seen that the adhesion property between the silver electrode and the glass substrate is excellent. That is, the film was firmly adhered to the substrate without peeling phenomenon. It can be seen that the glass components constituting the composite powder of silver and glass react with the glass substrate while being moved under the electrode during firing to improve adhesion properties between the silver electrode and the glass substrate. The resistivity of the conductive films was measured by a four-point electrical conductivity measuring device. The resistivity values of the samples shown in FIGS. 4, 5 and 6 had low values of 2.506, 2.418, and 3.963 μΩ · cm, respectively.

Comparative Example 1 Synthesis and Membrane Properties of Silver Powder Containing Glass

   Example 1 and the same production conditions, but in the powder synthesis, a pure silver powder containing no glass component was synthesized by a spray pyrolysis process. The reactor temperature for powder synthesis was 1300 ° C. The synthesized pure silver powder had a spherical shape, and XRD analysis showed pure silver crystal structure. 8 and 9 show the surface and the cut section of the electrode subjected to the firing process at 550 ° C. by pasting and screen printing the synthesized silver powder under the same conditions as in Example 3. The surface of the electrode obtained from the silver powder which the glass component does not contain shows the surface characteristic which is very porous because of poor plasticity characteristics. In addition, as can be seen in Figure 9 it can be seen that the peeling phenomenon occurs between the glass substrate and the electrode. The specific resistance of the electrode obtained from the pure silver powder was 2.927 µΩ · cm, which was higher than the electrode obtained from the composite powder of silver and glass.

Comparative Example 2: Properties of Electrode Obtained from Commercial Ag Powder and Spherical Glass Powder

Glass powders were synthesized by spray pyrolysis at a reactor temperature of 1300 ° C. with the glass composition of Example 1. Using the synthesized glass powder and commercially available Ag powder, a paste was prepared under the same conditions as in Example 3, and an electrode was formed by screen printing and baking. 10 shows the surface of the electrode. The surface of the electrode has porous properties with many pores. That is, comparing the results of Example 3 and Comparative Example 2, it can be seen that the electrode formed from the composite powder of silver and glass has a very dense structure compared to the electrode obtained from the mixture of silver and glass powder. This phenomenon is excellent in plasticity because of the excellent mixing properties between silver and glass components in the composite of silver and glass. The specific resistance of the sample shown in FIG. 10 was 2.912 µΩ · cm.

1 is an electron micrograph of the composite powder of silver and glass synthesized when the reactor temperature is 1000 ℃ each;

2 is an electron micrograph of the composite powder of silver and glass synthesized when the reactor temperature is 1300 ℃ each;

3 is a crystal structure of a composite powder of silver and glass synthesized when the reactor temperature is 1000 and 1300 ° C., respectively;

4 shows surface characteristics of an electrode obtained at a firing temperature of 550 ° C. when the glass components are each 1 wt%;

5 shows surface characteristics of an electrode obtained at a firing temperature of 550 ° C. when the glass components are each 3 wt%;

6 shows surface characteristics of an electrode obtained at a firing temperature of 550 ° C. when the glass components are 5% by weight, respectively;

7 is an electron micrograph showing a cut section of the sample shown in FIG. 5;

8 is a surface of an electrode subjected to a baking process at 550 ° C. by using a synthesized silver powder to make a paste and screen printing;

FIG. 9 is a cross-sectional view of an electrode having a paste prepared using synthesized silver powder, screen printed, and calcined at 550 ° C .; And

Fig. 10 shows the surface of the electrode formed using the synthesized glass powder and Ag powder commercially available.

Claims (17)

delete delete delete delete delete delete delete delete delete delete (a) dissolving silver and bismuth oxide (Bi ₂ O ₃ ), boron oxide (B ₂ O ₃ ), zinc oxide (ZnO) and additives in water, alcohol or acid to obtain a composite powder precursor solution of silver and glass step; (b) injecting the precursor solution into a spray device to generate droplets; And (C) a method for producing a composite powder of silver and glass comprising the step of introducing the generated droplets into the reactor to produce a composite powder of silver and glass at a temperature of 600 ~ 1500 ℃. The method of claim 11, wherein the additive is at least one compound selected from the group consisting of silica (SiO ₂ ), barium oxide (BaO), alumina (Al ₂ O ₃ ), and sodium oxide (Na ₂ O). Method for producing a composite powder of silver and glass. 12. The method of claim 11, wherein the silver component in the composite is 97 to 99% by weight and the glass component is 1 to 3% by weight. 12. The method of claim 11, wherein the concentration of the precursor solution is 0.02 to 3M. 12. The method of claim 11, wherein the droplets have a diameter of 0.1 to 100 µm in diameter. The method of claim 11, wherein the temperature in the reactor is 600 to 1500 ° C. 13. The method of claim 11, wherein the spray device is an ultrasonic atomizer, an air nozzle sprayer, ultrasonic nozzle sprayer, disk type droplet generator or filter expansion droplet generator for producing a composite powder of silver and glass, characterized in that Way.

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