KR101079249B1 - Preparation method of porous ceramic film with nano-sized pores using low temperature process and porous ceramic film having nano-sized pores prepared thereby - Google Patents

Abstract

The present invention relates to a method for producing a porous ceramic thick film using a low temperature heat treatment process, and more particularly, powder mixing of the ceramic powder and the organic pore former powder (step 1); Depositing the mixed powder of step 1 on one side of the base material by room temperature vacuum powder spraying (step 2); And it relates to a method of manufacturing a porous ceramic thick film using a low-temperature heat treatment process comprising the step (step 3) of manufacturing a porous ceramic thick film by removing the organic pore-form formed by the heat treatment step in the deposited film. In the method for preparing a porous ceramic thick film according to the present invention, a coating film may be prepared using a room temperature vacuum powder spraying method, and a porous film which does not affect the reaction with the base material through low temperature heat treatment may be formed. Since ceramic thick films have nano-sized pores and particle distribution, they can be usefully used in porous ceramic thick films such as solid fuel cells, catalysts, dye-sensitized solar cells, and gas sensors by increasing electrode activity.

Ceramic Powder, Organic Pore Formant Powder, Room Temperature Vacuum Powder Spraying, Solid Fuel Cell

Description

Preparation method of porous ceramic film with nano-sized pores using low temperature process and porous ceramic film having nano-sized pores prepared thereby}

The present invention relates to a porous ceramic thick film using a low temperature heat treatment process and a porous ceramic thick film having nano-sized pores produced thereby.

In general, the porous membrane is widely used in the field of obtaining high efficiency through a large surface area, for example, active research in the field of electrode material, semiconductor oxide electrode material of dye-sensitized solar cell, photocatalyst, gas sensor thick film.

The solid oxide fuel cell prevents the mixing of fuel gas and oxidant (air) when the components are connected in series with a unit component having a porous cathode and an anode attached to both sides of a centrally dense electrolyte. It consists of a connecting material for electrical connection. In the cathode, oxygen adsorbed on the surface of the electrode moves through the dissociation / surface diffusion to the three-phase interface of the electrode / electrolyte to obtain electrons to form oxygen ions, and the generated oxygen ions move to the anode through the electrolyte. In the anode, the diffused oxygen ions react with hydrogen to release electrons and generate water and heat.

Among the components of the solid oxide fuel cell, the cathode has high ion conductivity and electron conductivity (50 (Ω · ㎝) ^-1 or more), is stable in an oxidizing atmosphere, free from chemical reactions and mutual diffusion with other components, and has a thermal window coefficient. Should be a similar porous (more than 30%) membrane. Materials currently used as cathode materials include LaMnO ₃ , LaCoO ₃ and precious metals.

In addition, the cathode-related material is a material having excellent electrode characteristics, and includes an electrode using a BSCF (BaSrCoFeO) single phase (Z. Shao, SMHalle, Nature, 431 (2004), 170-173), and nickel (Ni). There is a material that uses a composite of nickel (Ni) and ceria (Shanwen Tao, TSIrvine, Nature 2, (2003), 320-323) to construct the electrode without using it.

As a conventional method of manufacturing a porous thick film, a method of manufacturing a ceramic thick film by preparing a ceramic powder in the form of a slurry or a paste and screen printing and heat treating the screen printed slurry or paste is widely used. However, when the ceramic thick film is manufactured by the screen printing method, there is a problem that densification is difficult. In order to overcome this problem, a method of achieving densification by adding a glass phase which can be easily melted and filled in the heat treatment process between the particles and the particles during the manufacturing of the paste for the screen printing process or by pressurizing heat treatment during the heat treatment may be used.

In Korean Patent No. 284892, in the manufacture of a dense membrane using a pressure reduction / pressure type slurry coating apparatus, pressure is applied from the outside to cause pressure difference between both ends of the porous support to remove the solvent from the slurry in which the ceramic solid particles are dispersed, thereby coating the coating layer. It proposes a method for producing a dense membrane using a slurry coating method, characterized in that formed for the support.

However, the manufacture of porous thick films which manufacture and heat-treat existing ceramic powders in the form of slurry or paste is accompanied by heat treatment at high temperature for ceramic sintering, which leads to the complexity of the process, the limitation of the selection of the base material by the heat treatment, and the reaction with the base material. There is a drawback to this problem.

Thus, the inventors of the present invention while studying a method of manufacturing a porous ceramic thick film through a low temperature process, preparing a deposited film by using a room temperature vacuum powder spray method, the nano-sized pores do not affect the reaction with the base material through low temperature heat treatment To develop a method for producing a porous ceramic thick film having a completed the present invention.

An object of the present invention is to provide a method for producing a porous ceramic thick film using a low temperature heat treatment process.

Still another object of the present invention is to provide a porous ceramic thick film having nano-sized pores produced by the above method.

In order to achieve the above object, the present invention comprises the steps of powder mixing the ceramic powder and the organic pore-form powder (step 1); Depositing the mixed powder of step 1 on one side of the base material by room temperature vacuum powder spraying (step 2); And it provides a method for producing a porous ceramic thick film using a low-temperature heat treatment process comprising the step (step 3) of manufacturing a porous ceramic thick film by removing the organic pore-form formed by the heat treatment step in the deposited film.

In addition, the present invention provides a porous ceramic thick film having nano-sized pores that can be usefully used in thick films such as solid fuel cells, dye-sensitized solar cells and gas sensors by increasing the activity of the electrode.

In the method of manufacturing a porous ceramic thick film according to the present invention, a deposition film may be prepared by using a room temperature vacuum powder spraying method, and a porous film which does not affect the reaction with the base material through low temperature heat treatment may be formed. Since ceramic thick films have nano-sized pores and particle distribution, they can be usefully used in porous ceramic thick films such as solid fuel cells, catalysts, dye-sensitized solar cells, and gas sensors by increasing electrode activity.

The present invention comprises the steps of powder mixing the ceramic powder and the organic pore-former powder (step 1); Depositing the mixed powder of step 1 on one side of the base material by room temperature vacuum powder spraying (step 2); And it provides a method for producing a porous ceramic thick film using a low-temperature heat treatment process comprising the step (step 3) of manufacturing a porous ceramic thick film by removing the organic pore-form formed by the heat treatment step in the deposited film.

Hereinafter, the present invention will be described in detail with reference to the process flowchart of FIG. 1 and the process schematic of FIG. 3.

First, step 1 according to the present invention is a step of powder mixing the ceramic powder and the organic pore-form powder.

The ceramic powder of step 1 is preferably (La, Sr) MnO ₃ , (La, Sr) CoO ₃ , (La, Sr) FeO ₃ , LSM-YSZ, NiO-YSZ, TiO ₂ and Al ₂ O ₃ . .

In addition, it is preferable to use polyvinylidene fluoride (PVDF), polyimide (PI), polymethyl methacrylate (PMMA), and the like as the organic pore-forming body of step 1, and polyvinylidene fluoride (PVDF, More preferably, PVDF) is used.

In addition, the mixing of the step 1 is preferably a volume ratio of the organic pore-former content of 5 to 50% with respect to the ceramic powder. If the content is less than 5%, the number of micropores decreases, making it difficult to manufacture a porous ceramic thick film. If the content exceeds 50%, the number of micropores increases to decrease the strength of the ceramic thick film. there is a problem.

In addition, the powder mixture of step 1 may be a powder, such as ceramic powder and the organic pore-former powder may be wet ball milling or dry ball milling, etc. It can be mixed together during the deposition of.

Next, the step 2 according to the present invention is a step of depositing the mixed powder of the step 1 on one side of the base material by the room temperature vacuum powder spray method.

The manufacturing process of the room temperature vacuum powder spraying method may be performed by the composite coating film forming apparatus as shown in FIG. The mixed powder prepared in Step 1 is introduced into the powder dispersion container 1, and the base material 4 is mounted in the deposition chamber 2. The carrier gas is supplied from the carrier gas cylinder 7 into the powder dispersion cylinder 1. At this time, the carrier gas is preferably air, oxygen, nitrogen, helium, argon, and the like, and in forming the composite coating film, since the type of carrier gas does not significantly affect, a low cost gas may be used in consideration of manufacturing cost. Further, the flow rate of the carrier gas is adjusted in the range of 1 L / min or more so that the mixed powder inside the powder dispersion container 1 is scattered by the inflow of the carrier gas.

The carrier gas is introduced to the deposition chamber (2) and after the carrier gas is injected into the deposition chamber (2) is preferably maintained to a certain range by using a vacuum pump (5), room temperature vacuum powder according to the present invention The spraying method is more preferably maintained at a vacuum of 1 Torr in order to obtain an optimal coating layer.

The gas supplied to the powder dispersion container 1 introduces the dispersed mixed powder particles to the nozzle 3 of the deposition chamber 2, and the injected mixed powder particles are placed in the deposition chamber 2 through the nozzle 3. It is dispersed in (4) to form a coating layer of mixed powder. At this time, the base material 4 is moved by the stage 6 at a speed of 0.1-10 mm / sec, and the number of round trips of the base material 4 depends on the thickness of the coating layer to be formed.

The nozzle 3 is positioned at the lower end spaced apart from the base material 4 by a distance of about 1-40 mm, the width of the nozzle 3 is 0.1-0.2 mm, the length of the nozzle 3 Should be 5-300 mm.

Next, step 3 according to the present invention is a step of preparing a porous ceramic thick film by removing the organic pore-former powder by a heat treatment process in the deposition film.

The heat treatment process of step 3 is preferably performed at a temperature range of 300-500 ℃. If it is carried out at a high temperature exceeding 500 ℃, there is a problem that the process temperature is increased to increase the possibility of reaction with the base material, and when carried out at a temperature below 300 ℃, the pore-forming body is not sufficiently removed, such as carbon in the ceramic There is a problem that remains.

In addition, the present invention provides a porous ceramic thick film produced by the above-described manufacturing method.

The porous ceramic thick film according to the present invention preferably has a volume of 5-50% by volume. If the volume is less than 5% by volume, the number of micropores decreases, making it difficult to manufacture a porous ceramic thick film. If the volume is greater than 50% by volume, the number of the micropores increases, thereby decreasing the strength of the ceramic thick film.

The porous ceramic thick film according to the present invention includes pores having a size of 20-200 nm.

Furthermore, the present invention provides the use of the porous ceramic thick film prepared by the above method. Since the porous ceramic thick film according to the present invention has nano-sized pores and particle distribution, it can be usefully used to increase the activity of the electrode, so that the electrode material of the solid fuel cell, the electrode material of the dye-sensitized solar cell, the thick film of the gas sensor, and the like.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are merely to illustrate the invention, the content of the present invention is not limited by the following examples.

Example 1 Preparation of Porous Ceramic Thick Film 1

Step 1: Powder Mixing Ceramic Powder and Organics Pore Formant Powder

To the LSM-YSZ (6: 4) ceramic powder, add PVDF to the LSM-YSZ (6: 4) ceramic powder in a volume ratio of 50%, and mix by milling for 6 hours using zirconia (4Y-TZP) balls and alcohol. It was.

Step 2: depositing the mixed powder of step 1 on one side of the base material by the room temperature vacuum powder injection method

The mixed powder prepared in Step 1 is sprayed using a compressed air at a flow rate of 30 L / min through a 25 mm nozzle using a room temperature vacuum powder spray method and sprayed onto a silicon substrate at a distance of 10 mm from a nozzle to 10-50 μm. A thick film was deposited.

Step 3: preparing a porous ceramic thick film by removing the organic pore-former powder by a heat treatment process in the deposited film

PVDF was removed from the deposited film prepared in Step 2 by heat treatment at 500 ° C. for 1 hour to prepare a porous ceramic thick film.

Example 2 Preparation of Porous Ceramic Thick Film 2

A porous ceramic thick film was prepared in the same manner as in Example 1, except that PVDF was mixed at a volume ratio of 30% with respect to the LSM-YSZ (6: 4) ceramic powder.

Example 3 Preparation of Porous Ceramic Thick Film 3

A porous ceramic thick film was prepared in the same manner as in Example 1, except that PVDF was mixed at a volume ratio of 20% with respect to the LSM-YSZ (6: 4) ceramic powder.

Example 4 Preparation of Porous Ceramic Thick Film 4

A porous ceramic thick film was prepared in the same manner as in Example 1, except that PVDF was mixed at a volume ratio of 10% with respect to the LSM-YSZ (6: 4) ceramic powder.

Example 5 Preparation of Porous Ceramic Thick Film 5

A porous ceramic thick film was prepared in the same manner as in Example 1, except that PVDF was mixed at a volume ratio of 5% with respect to the LSM-YSZ (6: 4) ceramic powder.

Comparative Example 1 Preparation of Ceramic Thick Film Made of LSM-YSZ Only

A ceramic thick film was prepared in the same manner as in Example 1, except that PVDF, which is an organic pore former powder, was not added.

<Reference Experimental Example 1> Analysis of PVDF Powder as Organic Pore Forming Powder

In order to analyze PVDF powder which is an organic pore-former powder used in the present invention, it was observed with a scanning electron microscope (SEM, JEOL, JSM-5800), and the results are shown in FIG. 4.

1 is a scanning electron micrograph (Fig. 4 (a)) showing the shape of the PVDF powder, it can be seen that the particle size is 3.5 ㎛ through the particle size distribution (Fig. 4 (b)) of the PVDF.

Experimental Example 1 Phase Analysis of Ceramic Thick Films Deposited with Different Mixing Ratios of LSM and YSZ

For phase analysis of ceramic thick films made of ceramic powders having different mixing ratios of LSM and YSZ, an X-ray diffractometer (XRD, Rigaku co., D-MAX 2200) was analyzed and the results are shown in FIG. 5. .

5, PVDF is mixed in a volume ratio of 20% for LSM-YSZ (3: 7), LSM-YSZ (5: 5), LSM-YSZ (7: 3), and LSM ceramic powder, respectively. The mixed powder of was deposited on one side of the base material by room temperature vacuum powder spraying, and the deposited film was analyzed by X-ray diffractometer.

Only the LSM phase appeared in the deposition film composed of LSM ceramic powder only, and both LSM and YSZ phases appeared in the other coating films, indicating that the two powders were mixed and deposited. In addition, it can be seen that as the LSM ratio increases, the size of the LSM peak increases.

Experimental Example 2 Phase Analysis of Ceramic Thick Films Deposited by Different Contents of PVDF Added to LSM-YSZ (6: 4) Powders

The amount of PVDF added to the ceramic powder mixed with LSM-YSZ at 6: 4 was analyzed by X-ray diffractometer (XRD) for phase analysis of the deposited ceramic thick film, and the results are shown in FIG. 6. .

6, as a result of analyzing the deposited film prepared in Step 2 of Examples 1, 2, 3, 4 and 5 by X-ray diffractometer, both LSM and YSZ phases appear and thus the coating film containing LSM-YSZ. It can be seen that it was deposited.

Experimental Example 3 Analysis of the Film Deposited by Room Temperature Vacuum Spraying and the Coating Film After Low Temperature Heat Treatment

In order to analyze the microstructure of the ceramic thick film prepared in step 2 of Example 1 and the porous ceramic thick film prepared in step 3, scanning electron microscope (SEM, JEOL, JSM-5800) and X-ray spectroscopy (EDS, JEOL, JSM-5800) mapping and the results are shown in FIG. 7.

Referring to FIG. 7, it can be seen from the photograph showing the surface of the ceramic thick film prepared in step 2 of Example 1 that the thick film produced has a dense structure (see FIG. 7A), and the X-ray As a result of spectroscopic mapping, the quantitative analysis shows that the ratio of Mn / (Mn + Zr + Y) is 0.598, indicating that LSM-YSZ is mixed at a 6: 4 molar ratio. It can be seen that they are mixed and distributed (see FIG. 7B). In addition, it can be seen from the photograph showing the surface of the porous ceramic thick film prepared in step 3 of Example 1 that the pore was formed by removing the PVDF (see FIG. 7C), and the porous ceramic prepared in Example 1 It can be seen from the photograph showing the cross section of the thick film that the LSM-YSZ is uniformly deposited on one side of the base material (see FIG. 7 (d)).

Experimental Example 4 Analysis of Microstructure of Porous Ceramic Thick Film 1

In order to analyze the microstructures of the porous ceramic thick films prepared in Examples 1, 2, 3, 4, and 5 and the ceramic thick films prepared in Comparative Example 1, the results were analyzed by scanning electron microscopy (SEM, JEOL, JSM-5800). The results are shown in FIG.

Scanning electron microscope analysis shows that the pore increases as the PVDF content increases.

Experimental Example 5 Analysis of Microstructure of Porous Ceramic Thick Film 2

In order to analyze the microstructure of the porous ceramic thick film prepared in Example 3, it was analyzed by transmission electron microscope (TEM, JEOL, JSM-2100F) and X-ray spectroscopy (EDS, JEOL, JSM-2100F) mapping. Is shown in FIG. 9.

Figure 9 (a) shows the microstructure of the porous ceramic thick film prepared in Example 3, it can be seen that the YSZ distribution in Figure 9 (b), the LSM is distributed in Figure 9 (c) It can be seen. Through the analysis, it can be seen that pores having a size of 20-200 nm were formed in the porous ceramic thick film, and the porous ceramic thick film was formed by combining LSM-YSZ.

1 is a flow chart showing a manufacturing process of a porous ceramic thick film according to the present invention;

2 is a schematic view of a composite coating forming apparatus for producing a porous ceramic thick film according to the present invention;

3 is a schematic view showing a manufacturing process of a porous ceramic thick film according to the present invention;

Figure 4 is a graph showing a scanning electron micrograph (Fig. 4 (a)) and particle size distribution (Fig. 4 (b)) of the PVDF powder which is a porous forming powder;

5 is X-ray diffraction analysis results of ceramic thick films deposited by varying the mixing ratio of LSM and YSZ;

FIG. 6 shows the results of X-ray diffraction analysis of ceramic thick films deposited by varying the amount of PVDF added in step 1 of Examples 1, 2, 3, 4, and 5;

7 is a scanning electron micrograph and X-ray spectroscopic mapping results of the ceramic thick film prepared in Step 2 of Example 1 and the porous ceramic thick film prepared in Example 1;

8 is a scanning electron micrograph of the porous ceramic thick film prepared in Examples 1, 2, 3, 4, and 5 and the ceramic thick film prepared in Comparative Example 1; And

9 is a transmission electron micrograph and X-ray spectroscopic mapping analysis results of the porous ceramic thick film prepared in Example 3.

<Description of symbols for important parts of the drawings>

1: powder dispersion barrel

2: deposition chamber

3: nozzle

4: base material

5: vacuum pump

6: x-y-z stage

7: carrier gas cylinder

8: spray nozzle

9: mixed powder

10: substrate substrate

11: Composite coating film

12: porous ceramic thick film

S100: powder mixing step

S200: complex coating film forming step

S300: micropore forming step

Claims (8)

Powder-mixing the ceramic powder and the organic pore former powder (step 1); Depositing the mixed powder of step 1 on one side of the base material by room temperature vacuum powder spraying (step 2); And The method of manufacturing a porous ceramic thick film using a low-temperature heat treatment process comprising the step (step 3) of manufacturing a porous ceramic thick film by removing the organic pore forming body by the heat treatment step in the deposited film. The method of claim 1, wherein the ceramic powder of step 1 is (La, Sr) MnO ₃ , (La, Sr) CoO ₃ , (La, Sr) FeO ₃ , LSM-YSZ, NiO-YSZ, TiO ₂ or Al ₂ Method for producing a porous ceramic thick film, characterized in that O ₃ . The method of claim 1, wherein the organic pore-forming body of step 1 is polyvinylidene fluoride (PVDF), polyimide (PI) or polymethyl methacrylate (PMMA). The method of claim 1, wherein the powder mixture of step 1 is a method for producing a porous ceramic thick film, characterized in that the content of the organic pore-forming body is 5 to 50% by volume with respect to the ceramic powder. The method of claim 1, wherein the heat treatment process of step 3 is carried out at a temperature range of 300-500 ℃. A porous ceramic thick film prepared by the method of claim 1 having from 5 to 50% by volume of nanopores. The porous ceramic thick film of claim 6, wherein the porous ceramic thick film has pores having a size of 20-200 nm. The porous ceramic thick film of claim 6, wherein the porous ceramic thick film is used as an electrode material of a solid oxide fuel cell.

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