KR101947414B1 - Manufacturing method of porous metal membrane having fine pores - Google Patents

Abstract

The present invention relates to a method for producing a metal powder by mixing two or more kinds of metal powders having different average particle sizes by weight in consideration of packing density and porosity of a membrane and mixing them in a mixer and mixing the mixed powder and the binder, A step of charging a mixture of the binder and the mixed powder into a mold and then pressing the resultant with a press machine to mold the resultant product; demolding the resultant product in the mold; Charging the sintering furnace to degrease the binder at a temperature higher than the temperature at which the binder is pyrolyzed and at a temperature lower than the melting temperature of the mixed powder to raise the temperature to a sintering temperature to sinter the sintered body; Polishing and drying for removal of the electrolytic polishing liquid, and drying the dried sintered body And performing a baking process in a vacuum sintering furnace to burn and remove the electrolytic polishing liquid component remaining in the fine pores.

Description

Technical Field [0001] The present invention relates to a porous metal membrane having fine pores,

The present invention relates to a method for producing a porous metal membrane, and more particularly, to a method for producing a porous metal membrane, which is simple in manufacturing method, low in process cost, excellent in mechanical strength, easy in controlling porosity, low in surface roughness, ≪ / RTI > to a process for producing a porous metal membrane.

Generally, the process gas used for manufacturing semiconductor wafers is HCl, BCl 3, CF 4 and the like, which is corrosive to the reaction chamber and the gas piping. The impurity particles due to the process gas cause contamination of the reaction chamber and damage of the wafer, thereby deteriorating the aging of the reaction chamber and the yield of the wafer.

Therefore, it is very important to introduce a gas filter for controlling the impurity particle at a certain point in the gas pipe connected to the semiconductor manufacturing facility. The gas filter for controlling the impurity particle maintains extreme cleanliness of ultrahigh purity gas and chemicals used in the manufacturing process, thereby enhancing the stability of the manufacturing process. The highly corrosive ultra-clean gas filter is a core component that is needed not only in the semiconductor production process but also in the fields of display, fine chemicals, bio, nuclear, and aerospace.

Therefore, the development of an ultra clean gas filter for controlling the impurity particle is very important in the present situation where the necessity of the related parts and materials increases as the industry becomes more sophisticated.

The gas filter is composed of a porous membrane that permeates the gas and filters the impurity particles, and a housing that supports and connects to the gas pipe. The most important part of the gas filter is a membrane through which the gas passes directly. Recently, the material of interest is easy to manufacture, has a high fluid permeability and a uniform pore distribution, and the pore surface is smooth, It is a metal membrane.

The metal membrane has the advantage of being able to manufacture a gas filter which has a higher tensile characteristic than a ceramic or polymer membrane and is free from the risk of breakage. In particular, nickel has good corrosion resistance and sintering properties and is suitable for membrane production. However, in the case of ordinary metal membranes, the size of the pores is larger than the polymer membrane and is not uniform. Therefore, methods have been used in which a metal is formed into a wire, followed by molding and sintering, or dispersed in a polymer solution to prepare a slurry and sintering. The gas filter using these methods has a disadvantage that the control of the impurity particle is not efficient due to the difficulty in controlling the size and distribution of the pore, because the gas filter having high porosity shows high air permeability but is complicated due to the complicated manufacturing process have.

On the other hand, in the case of the filter membrane using the metal powder, the cost is lower than that of the metal fiber, the molding can be performed in various shapes, and the porosity lower than 30% is pointed out as a problem even though it shows good mechanical strength.

Korean Patent Registration No. 10-0911133

The present invention provides a method for producing a porous metal membrane having a simple manufacturing method, a low process cost, excellent mechanical strength, easy control of porosity, low surface roughness and micropores .

The present invention relates to a method for producing a metal powder by mixing two or more kinds of metal powders having different average particle sizes by weight in consideration of packing density and porosity of a membrane and mixing them in a mixer and mixing the mixed powder and the binder, A step of charging a mixture of the binder and the mixed powder into a mold and then pressing the resultant with a press machine to mold the resultant product; demolding the resultant product in the mold; Charging the sintering furnace to degrease the binder at a temperature higher than the temperature at which the binder is pyrolyzed and at a temperature lower than the melting temperature of the mixed powder to raise the temperature to a sintering temperature to sinter the sintered body; Polishing and drying for removal of the electrolytic polishing liquid, and drying the dried sintered body And performing a baking step in a vacuum sintering furnace to burn and remove the electrolytic polishing liquid component remaining in the fine pores.

The two or more different metal powders preferably include a first metal powder having an average particle size of 1 to 20 mu m and a second metal powder having an average particle size of 2 to 4 times larger than the first metal powder.

Before mixing in the mixer, the metal powder may be classified according to the particle size using a classifier.

The sorting device is a device in which sieves having different sieve sizes are sequentially arranged at different positions (height), and a sieve having the largest sieve size is mounted on the uppermost portion of the sorting device, A vibrator for vibrating the sieves to smoothly classify the sieves is mounted on the lower part of the classifier and vibration energy is generated by the vibrator. It is transmitted to the sieve so that each sieve is classified.

In consideration of porosity and pore size of the produced porous metal membrane, it is preferable to use paraffin wax as the binder.

It is preferable that the metal powders include at least one powder selected from stainless steel, Hastelloy, and nickel.

It is preferable that the binder is mixed in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the mixed powder.

It is preferable to apply pressure of 80 to 120 bar by using the above press equipment.

Wherein the mold has a rod-like structure having a larger length as a whole than the diameter, an inner body portion of a metal material is provided at the center of the mold, and an outer body portion of a metal material is provided so as to surround and surround the inner body portion, A space is formed between the body part and the inner body part to receive a mixture of the binder and the mixed powder and to adjust the space between the outer body part and the inner body part to determine the thickness of the porous metal membrane, The diameter of the porous metal membrane is determined to determine the inner diameter of the porous metal membrane (the diameter of the hollow space), and the length of the mold is adjusted to determine the length of the porous metal membrane. The porous metal membrane may have a hollow tubular shape have.

The degreasing is preferably performed at a temperature of 400 to 800 ° C.

The sintering is preferably performed at a temperature higher than the temperature at which the binder is thermally decomposed and lower than the melting temperature of the mixed powder at 900 to 1200 ° C.

The degreasing and sintering is preferably performed in an argon gas atmosphere containing H ₂ .

The electrolytic polishing solution may be an electrolytic polishing solution containing sulfuric acid (H ₂ SO ₄ ), phosphoric acid (H ₃ PO ₄ ), distilled water and a surfactant, or an electrolytic polishing solution containing sulfuric acid (H ₂ SO ₄ ), phosphoric acid (H ₃ PO ₄ ) , A surfactant, and chromium (Cr).

The baking is preferably carried out at a temperature higher than the boiling point of the electrolytic polishing liquid component and lower than the melting temperature of the metal membrane at 150 to 400 캜.

The baking is preferably performed in an argon gas atmosphere containing H ₂ .

According to the present invention, the production method is simple, the process cost is low, the mechanical strength is excellent, and the porosity is easily controlled.

The porous metal membrane produced by the present invention has a low surface roughness and has micropores.

FIG. 1 is a view showing a mold for molding according to an example, and is a sectional view cut in a direction perpendicular to the length.
FIG. 2 is a view showing a tubular porous metal membrane manufactured using the mold shown in FIG. 1, and is a sectional view cut along the direction perpendicular to the length.
3 to 5 are views showing the surface of a tubular porous metal membrane produced according to an experimental example.
FIG. 6 is a graph showing the results of performing a flow test on a tubular porous metal membrane manufactured according to an experimental example.
FIGS. 7A and 7B are graphs showing the results of performing a porosity test on the porous metal membrane prepared according to the experimental example.
FIGS. 8A and 8B are graphs showing the results of the air permeability test on the porous metal membrane manufactured according to the experimental example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it should be understood that the following embodiments are provided so that those skilled in the art will be able to fully understand the present invention, and that various modifications may be made without departing from the scope of the present invention. It is not. Wherein like reference numerals refer to like elements throughout.

Hereinafter, the term " metal " means not only pure metal but also metal alloy.

The method of manufacturing a porous metal membrane having micropores according to a preferred embodiment of the present invention includes the steps of charging two or more kinds of metal powders having different average particle sizes by weight in consideration of packing density and porosity of the membrane, Mixing the mixed powder and the binder mixed in the mixer into a heating mixer and mixing them; charging the mixture of the binder and the mixed powder into a mold and pressing the mixture with a press machine; The binder is degreased at a temperature higher than the temperature at which the binder is pyrolyzed and is lower than the melting temperature of the mixed powder, and the sintered product is sintered at a sintering temperature of A step of heating and sintering, a step of electrolytically polishing the sintered body using an electrolytic polishing liquid, , Washing and drying to remove the electrolytic polishing liquid, and performing a baking process in a vacuum sintering furnace to burn and remove the electrolytic polishing liquid component remaining in the micropores of the dried sintered body.

The two or more different metal powders preferably include a first metal powder having an average particle size of 1 to 20 mu m and a second metal powder having an average particle size of 2 to 4 times larger than the first metal powder.

Before mixing in the mixer, the metal powder may be classified according to the particle size using a classifier.

The sorting device is a device in which sieves having different sieve sizes are sequentially arranged at different positions (height), and a sieve having the largest sieve size is mounted on the uppermost portion of the sorting device, A vibrator for vibrating the sieves to smoothly classify the sieves is mounted on the lower part of the classifier and vibration energy is generated by the vibrator. It is transmitted to the sieve so that each sieve is classified.

In consideration of porosity and pore size of the produced porous metal membrane, it is preferable to use paraffin wax as the binder.

It is preferable that the metal powders include at least one powder selected from stainless steel, Hastelloy, and nickel.

It is preferable that the binder is mixed in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the mixed powder.

It is preferable to apply pressure of 80 to 120 bar by using the above press equipment.

Wherein the mold has a rod-like structure having a larger length as a whole than the diameter, an inner body portion of a metal material is provided at the center of the mold, and an outer body portion of a metal material is provided so as to surround and surround the inner body portion, A space is formed between the body part and the inner body part to receive a mixture of the binder and the mixed powder and to adjust the space between the outer body part and the inner body part to determine the thickness of the porous metal membrane, The diameter of the porous metal membrane is determined to determine the inner diameter of the porous metal membrane (the diameter of the hollow space), and the length of the mold is adjusted to determine the length of the porous metal membrane. The porous metal membrane may have a hollow tubular shape have.

The degreasing is preferably performed at a temperature of 400 to 800 ° C.

The sintering is preferably performed at a temperature higher than the temperature at which the binder is thermally decomposed and lower than the melting temperature of the mixed powder at 900 to 1200 ° C.

The degreasing and sintering is preferably performed in an argon gas atmosphere containing H ₂ .

The electrolytic polishing solution may be an electrolytic polishing solution containing sulfuric acid (H ₂ SO ₄ ), phosphoric acid (H ₃ PO ₄ ), distilled water and a surfactant, or an electrolytic polishing solution containing sulfuric acid (H ₂ SO ₄ ), phosphoric acid (H ₃ PO ₄ ) , A surfactant and chromium (Cr). The surfactant may include ethylene glycol, water and nicotinamide.

The baking is preferably carried out at a temperature higher than the boiling point of the electrolytic polishing liquid component and lower than the melting temperature of the metal membrane at 150 to 400 캜.

The baking is preferably performed in an argon gas atmosphere containing H ₂ .

Hereinafter, a method of manufacturing a porous metal membrane according to a preferred embodiment of the present invention will be described in more detail.

Two or more kinds of metal powders having different average particle sizes are weighed in consideration of filling density and porosity of the membrane and mixed in a mixer.

Metal powders such as stainless steel, Hastelloy, Nickel, and mixtures thereof are used as raw materials for producing porous metal membranes. The metal powders use two or more metal powders having different average particle sizes. Wherein the two or more different metal powders include a first metal powder having an average particle size of 1 to 20 mu m and a second metal powder having an average particle size of 2 to 4 times larger than the first metal powder, (Porosity), pore size, and the like.

Prior to mixing in the mixer, the metal powders may be classified according to the particle size using a classifier. The classifier is a device in which sieves having different sieve sizes are sequentially arranged at different positions (height). For example, a sieve having the largest sieve size (for example, a sieve having a sieve size of 125 mu m) is mounted on the uppermost portion of the classifying device, and a sieve having a small sieve size Mu] m. For example, a classification device equipped with seven sieves can be used. A first sieve having a sieve size of 125 mu m, a second sieve having a sieve size of 106 mu m, a third sieve having a size of 90 mu m, A fifth body having a sieve opening size of 45 mu m, a sixth body having a sieve opening size of 38 mu m, and a seventh body having a sieve opening size of 20 mu m can be used. In the case of using such a classifier, each particle size, that is, 125 占 퐉 or more, 106 占 퐉 or more and 125 占 퐉 or less, 90 占 퐉 or more and 106 占 퐉 or less, 75 占 퐉 or more and less than 90 占 퐉, 45 占 퐉 or more and less than 75 占 퐉, Mu] m, less than 20 [micro] m and less than 38 [micro] m, and less than 20 [micro] m.

In addition, a vibrator for vibrating the sieves and classifying them smoothly may be mounted on the lower part of the classifier. The vibrator is a device for generating vibrations, and vibration energy is transmitted to the sieves, so that classification is actively performed in each sieve.

And classified according to the particle size of the metal powder by the classifier.

Metal powders having respective particle sizes are selected from the metal powders and mixed according to the particle size according to their weight and mixed using a mixer (for example, a three-dimensional mixer). It is possible to increase the packing density and reduce the pore size in the case of mixing the metal powder having a large particle size and the metal powder having a small particle size compared with the case where the metal powder having a large particle size is mixed with each other. The packing density, the porosity (porosity) of the membrane, and the pore size can be controlled by selecting and classifying the metal powders classified according to the particle size.

The mixed powder and the binder mixed through the mixer are put into a heat mixer and mixed. As the binder, organic binders generally used for easy molding can be used. However, paraffin wax is most preferably used in consideration of the porosity and pore size of the porous metal membrane to be produced. It is preferable that the binder is mixed in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the mixed powder. If the content of the binder is less than 0.1 part by weight, molding may be difficult. If the content of the binder is more than 5 parts by weight, the target porosity may be higher than the target porosity. The mixing in the heating mixer is preferably performed at a temperature of about 80 to 180 DEG C for 10 minutes to 24 hours.

Since the mixed powder is aggregated due to the binder, it may be classified using a sieve having a sieve (for example, 300 to 800 m) larger than the sieve size at the time of classification.

FIG. 1 is a view showing a mold for molding according to an example, and is a sectional view cut in a direction perpendicular to the length. The mold shown in Fig. 1 is a mold for manufacturing a tubular porous metal membrane. The porous metal membrane may be formed into a tubular shape or a disk shape, a rod shape or the like although not shown.

After the mixture of the binder and the powder mixture is charged into the mold 10, the mixture is molded at a constant pressure (for example, 80 to 120 Bar) using a press machine. The pressing using the press equipment is preferably performed for 1 minute to 24 hours. As shown in FIG. 1, the mold 10 may be provided with an outer body portion 14 made of a metal and provided with a metal inner body portion 12 at a central portion and surrounding the inner body portion 12, A space is formed between the outer body portion 14 and the inner body portion 12 to accommodate powder (a mixture of the binder and the mixed powder). The outer body portion 14 is made of a hard metal such as stainless steel. The inner body portion 12 is made of a hard metal material such as stainless steel. The space between the outer body part 14 and the inner body part 12 is a factor for determining the thickness of the tubular membrane and is adjusted by adjusting the space between the outer body part 14 and the inner body part 12, Membrane can be formed. The mold 10 has a rod-like structure having a larger length as a whole (for example, a length / diameter ratio of 10 or more) as a whole. The length of the mold 10 is a factor determining the length of the tubular membrane, and thus the length of the mold 10 can be adjusted to form a tubular membrane of a desired length. The diameter of the inner body portion 12 is an element for determining the inner diameter of the tubular membrane (the diameter of the hollow space), so that the inner diameter of the inner body portion 12 can be adjusted to form a tubular shape having a desired inner diameter Membrane can be formed. In the case of forming a rod-shaped or disk-shaped membrane, a mold not provided with an inner body portion may be used.

The molded product is demolded in the mold (10). In the case of using the mold shown in Fig. 1, the molded product has a hollow tubular shape inside.

The formed product is charged into a vacuum sintering furnace, and the binder is degreased at a temperature higher than the temperature at which the binder is pyrolyzed and lower than the melting temperature of the mixed powder (for example, 400 to 800 ° C) do. Because the binder uses polymers, it is generally pyrolyzed at temperatures below 400 ° C. Therefore, when the sintering furnace temperature is raised to 400 ° C or higher, the binder is pyrolyzed. The degreasing and sintering is preferably performed in a reducing gas atmosphere (for example, an argon gas containing 4% of H ₂ ) atmosphere. The sintering is preferably performed at a temperature higher than the temperature at which the binder is pyrolyzed and lower than the melting temperature of the mixed powder (for example, 900 to 1200 ° C, more preferably 950 to 1150 ° C). Pores are generated by thermal decomposition of the binder, and pores are formed by the process of sintering to form a porous membrane. The degreasing is preferably carried out at a degreasing temperature (for example, 400 to 800 ° C.) for 1 minute to 6 hours. The sintering is preferably performed by maintaining the sintering at a sintering temperature (for example, 900 to 1200 DEG C, more preferably 950 to 1150 DEG C) for 10 minutes to 12 hours. The sintering is preferably performed in a vacuum state (for example, 5.7 x 10 < ^-2 > Torr) lower than normal pressure. The degreasing temperature is preferably raised at a heating rate of 0.1 to 50 ° C / min, and the sintering temperature is preferably raised at a heating rate of 0.1 to 50 ° C / min.

After performing the sintering process, the temperature of the sintering furnace is lowered to unload the sintered body. The sintering furnace may be cooled by shutting off the power supply to the sintering furnace to cool the sintering furnace in a natural state, or by setting a temperature lowering rate (for example, 10 ° C / min) arbitrarily.

The sintered body thus produced is a porous metal membrane, and performs an electrolytic polishing process to remove contaminants on the inner and outer surfaces of the membrane and to reduce roughness. Electrolytic polishing may be performed using any electrolytic polishing solution capable of electrolytic polishing within a range that does not impair the object of the present invention. Preferably, the electrolytic polishing solution is prepared by adding sulfuric acid (H ₂ SO ₄ ), phosphoric acid (H ₃ PO ₄ ), distilled water, Or an electrolytic polishing liquid containing additives such as sulfuric acid (H ₂ SO ₄ ), phosphoric acid (H ₃ PO ₄ ), distilled water, surfactant, chromium (Cr), etc. is used as the electrolytic polishing liquid. It is not. The surfactant may be one comprising ethylene glycol, water and nicotinamide. The electrolytic polishing is preferably performed for both the inside and the outside in the case of a porous metal membrane tubular type.

After the electrolytic polishing step, a cleaning step is performed to remove the electrolytic polishing liquid. For example, in order to remove the electrolytic polishing solution, a water tank is inserted into the front end of the membrane, the wafer is washed with high-pressure water for about 1 to 60 minutes, and the membrane is immersed in hot deionized water (for example, And ultrasonic cleaning is carried out.

When the cleaning process is completed, it is dried to remove the cleaning liquid. The drying is preferably performed by spraying nitrogen for about 1 to 60 minutes to remove deionized water from the membrane and performing the drying at a temperature of about 60 to 150 DEG C for about 10 minutes to about 24 hours in an air drying furnace.

A baking process is performed in a vacuum sintering furnace to burn and remove the electrolytic polishing liquid component (for example, sulfur, phosphoric acid) remaining in the fine pores (10 μm or less). The baking step is preferably carried out in an atmosphere of reducing gas (for example, argon gas containing 4% of H ₂ ). The baking process is preferably performed at a temperature higher than the boiling point of the electrolytic polishing liquid component such as sulfur, phosphoric acid and the like and lower than the melting temperature of the metal membrane (for example, 150 to 400 캜). The baking process is preferably performed at a vacuum state (for example, 5.7 x 10 < ^-2 > Torr) lower than normal pressure. It is preferable to raise the temperature up to the baking temperature at a rate of 0.1 to 50 ° C / min.

Porous metal membranes can be easily manufactured through upper limit processes.

2 is a view showing a tubular porous metal membrane, which is a cross-sectional view taken in a direction perpendicular to the length. Referring to FIG. 2, the porous metal membrane 100 manufactured using the mold shown in FIG. 1 has an empty tubular shape. The porous metal membrane may be manufactured in the form of a tubular shape or a disk shape, a rod shape or the like although not shown in the drawing.

Hereinafter, experimental examples according to the present invention will be specifically shown, and the present invention is not limited to the following experimental examples.

<Experimental Example>

1. Material

Stainless steel 316L powder was used. Stainless steel 316L powder used as a raw material was powder having an average particle size of 10 μm and powder having an average particle size of 30 μm.

2. Mix

2: 8, 3: 7, 4: 6, 5: 5, 6: 4, 7: 3, 8: 2, 9: 1, 10: 0 weight ratio, and mixed using a three-dimensional mixer for 30 minutes. Powders of different particle sizes (powders having an average particle size of 10 占 퐉 and powders having an average particle size of 30 占 퐉) were mixed at a rotation speed of 60 rpm using a three-dimensional mixer.

3. Binder Mix

The mixture powder mixed with the three-dimensional mixer and the paraffin wax as a binder were put into a heating mixer and mixed at a temperature of 120 ° C for 1 hour and 30 minutes. The paraffin wax was added in a proportion of 3.0 wt% based on 200 g of the mixed powder.

4. Classification of mixed powder

Since the mixed powder was aggregated due to the binder, it was classified using a sieve having a sieve size of 500 mu m.

5. Molding

A metal mold was prepared to prepare a molded article having an outer diameter of 30 mm and a length of 100 mm and 120 g of the mixture of the binder and the mixed powder was charged into a metal mold and pressure was maintained at 100 bar for 10 minutes . The metal mold has an inner body portion at a center portion and an outer body portion made of a metal material so as to surround the inner body portion and be spaced apart from each other. A space is formed between the outer body portion and the inner body portion to accommodate powder (a mixture of the binder and the mixed powder).

6. Sintering

The resultant was placed in a vacuum sintering furnace and maintained at a temperature of 750 ° C for 1 hour in an argon (Ar) gas atmosphere (argon gas containing 4% of H ₂ ) to degrease the binder. At a sintering temperature of 1050 ° C The sintering was continued for 1 hour. The degree of vacuum of the vacuum sintering furnace was about 5.7 × 10 ^-2 Torr. The degreasing temperature was raised at a heating rate of 5 ° C / min, and the temperature was raised at a heating rate of 5 ° C / min until the sintering temperature.

7. Welding

Welding was performed using a micro TIG (Micro TIG) welder, and welding was carried out using workpieces made of the same material as the membrane.

8. Cleaning: In order to remove contaminants on the inner and outer surfaces of the porous membrane and to reduce roughness, the following process was carried out, and the process proceeded to the following six steps.

1) Electrolytic polishing (EP)

Electrolytic polishing was performed using an electrolytic polishing solution for two minutes inside and outside the membrane (mbembrane). The electrolytic polishing solution was used as that consisting of sulfuric acid (H ₂ SO ₄₎ 30% by volume of phosphoric acid (H ₃ PO ₄₎ 60% by volume of distilled water 5% by volume and 5% by volume surfactant. The surfactant used was 70% by volume of ethylene glycol, 20% by volume of water and 10% by volume of nicotinamide.

2) Washing time

In order to remove the electrolytic polishing solution, a water tank was inserted into the front end of the membrane and cleaned with high-pressure water for about 2 to 3 minutes.

3) Hot Deionized Water Cleaning and Ultrasonic Cleaning

The membrane was immersed in hot deionized water (deionized water at 60 캜) and subjected to ultrasonic cleaning. Two groups were used to clean each group for 10 minutes.

4) Nitrogen drying

Nitrogen was sparged for about 1-2 minutes to remove deionized water from the membrane.

5) Atmospheric drying

And dried at 100 DEG C for 1 hour in an air drying furnace.

6) Baking

In order to burn off the electrolytic polishing liquid component (for example, sulfur, phosphoric acid) remaining in the fine pores, the substrate was baked in an atmosphere of argon (Ar) gas (argon gas containing 4% H ₂ ) baking process. The degree of vacuum of the vacuum sintering furnace was about 5.7 × 10 ^-2 Torr. The temperature was raised to a baking temperature at a heating rate of 5 DEG C / min.

3 to 5 are views showing the surface of a tubular porous metal membrane produced according to an experimental example. Figs. 3 to 5 show a case where powders having an average particle size of 10 占 퐉 and powders having an average particle size of 30 占 퐉 are mixed as a raw material at a weight ratio of 4: 6.

3 to 5, it can be seen that there are numerous pores on the surface of the metal membrane to exhibit porosity. It can be seen that the micropores are 10 μm or less and most of the micropores are 1 μm or less.

Flow tests were performed on tubular porous metal membranes prepared according to the experimental examples and the results are shown in Table 1 and FIG. 6, wherein the flow test was carried out at a temperature of 18 ± 1 ° C of 50 ± 3% Relative humidity, and atmospheric pressure (1.003 bar). Table 1 and FIG. 6 show a case where powders having an average particle size of 10 μm and powders having an average particle size of 30 μm are mixed as a raw material at a weight ratio of 4: 6.

Shear pressure (psig) Flow rate (LPM) 10.0 1797 13.1 2295 16.4 2779 20.3 3287 29.2 4193 37.1 4950 45.3 5785 54.0 6630 61.3 7343 70.2 8211

Porous metal membranes prepared according to Experimental Examples were subjected to a porosity test. The results are shown in Tables 2, 7A and 7B. The porosity test was conducted using a Mercury porosimeter (AutoPore IV9500) 15901 was used. The sample weight was 3.1370 g, the stem volume used was 39%, and the test pressure was 0.5 to 61000 psi. Table 2, Figs. 7A and 7B show the case where powders having an average particle size of 10 mu m and powders having an average particle size of 30 mu m as raw materials are mixed at a weight ratio of 4: 6.

Test items Results Total intrusion volume (ml / g) 0.082 Total pore area (m 2 / g) 21.982 Average pore diameter (탆) 0.015 Porosity (%) 46.4

The air permeability test was performed on the prepared porous metal membrane according to the experimental example, and the results are shown in FIGS. 8A and 8B. FIGS. 8A and 8B show a case where powders having an average particle size of 10 .mu.m and powders having an average particle size of 30 .mu.m are mixed at a weight ratio of 4: 6.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, This is possible.

10: Mold
12: My body
14: external body part
100: Porous metal membrane

Claims (9)

Mixing two or more kinds of metal powders having different average particle sizes by weight in consideration of packing density and porosity of the membrane and mixing them in a mixer;
Mixing the mixed powder and the binder, which are mixed with two or more types of metal powders having different average particle sizes through the mixer, into a heat mixer;
Charging a mixture of the binder and the mixed powder into a mold, and pressing the mixture with a press machine;
Demolding the molded product in the mold;
Charging the resulting vacuum degassed product into a vacuum sintering furnace, maintaining the binder at a temperature higher than the temperature at which the binder is pyrolyzed and lower than the melting temperature of the mixed powder to degrease the binder, and heating and sintering the mixture at a sintering temperature;
Electrolytically polishing the sintered body using an electrolytic polishing solution;
Cleaning and drying for removal of the electrolytic polishing liquid; And
And performing a baking process in a vacuum sintering furnace to burn and remove the electrolytic polishing liquid component remaining in the micropores of the dried sintered body,
Wherein the two or more different metal powders include a first metal powder having an average particle size of 1 to 20 mu m and a second metal powder having an average particle size of 2 to 4 times larger than the first metal powder,
Wherein the metal powder comprises one or more powders selected from the group consisting of stainless steel and Hastelloy.
delete The method of claim 1, wherein before mixing in the mixer,
Further comprising classifying the metal powders according to the particle size using a classifier,
The classifier is a device in which sieves having different sieve sizes are sequentially arranged at different positions (height)
A sieve having the largest sieve size is mounted on the uppermost part of the classifying device and a sieve having a smaller sieve size is mounted on the upper part of the classifying device,
A vibrator for vibrating the sieves to smoothly classify the sieves is mounted on the lower part of the classifier,
And vibrations are generated by the vibrator to transmit vibrational energy to the sieves, so that the sieving is performed in each sieve.
The method of claim 1, wherein the binder is a paraffin wax in consideration of porosity and pore size of the porous metal membrane to be produced,
Wherein the binder is mixed in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the mixed powder.
The method according to claim 1, wherein the pressure is applied at a pressure of 80 to 120 bar using the press machine.
2. The mold according to claim 1, wherein the mold has a rod-like structure having a larger length as a whole than the diameter,
Wherein a metal body is provided at a central portion of the mold and an outer body portion of a metal material is provided to surround the inner body portion and spaced apart from each other,
A space is formed between the outer body portion and the inner body portion to receive a mixture of the binder and the mixed powder,
Determining a thickness of the porous metal membrane by adjusting a space between the outer body portion and the inner body portion,
The diameter of the inner body portion is adjusted to determine the inner diameter (the diameter of the hollow space) of the porous metal membrane,
Determining the length of the porous metal membrane by adjusting the length of the mold,
Wherein the porous metal membrane has a tubular shape with an empty interior.
The method according to claim 1, wherein the degreasing is performed at a temperature of 400 to 800 캜,
The sintering is performed at a temperature higher than the temperature at which the binder is pyrolyzed and lower than the melting temperature of the mixed powder at 900 to 1200 ° C,
Wherein the degreasing and sintering is performed in an argon gas atmosphere containing H ₂ .
The electrolytic polishing solution according to claim 1, wherein the electrolytic polishing solution is an electrolytic polishing solution containing sulfuric acid (H ₂ SO ₄ ), phosphoric acid (H ₃ PO ₄ ), distilled water and a surfactant,
Wherein the electrolytic polishing liquid is an electrolytic polishing liquid containing sulfuric acid (H ₂ SO ₄ ), phosphoric acid (H ₃ PO ₄ ), distilled water, a surfactant, and chromium (Cr).
9. The method of claim 8, wherein the baking is performed at a temperature higher than the boiling point of the electrolytic polishing liquid component and lower than the melting temperature of the metal membrane,
Wherein the baking is performed in an argon gas atmosphere containing H ₂ .

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