KR20110122276A - Fe-cr-al base alloy porous structure and method of manufacturing by the same - Google Patents

Abstract

PURPOSE: A porous Fe-Cr-Al based alloy structure and a method for manufacturing the same are provided to achieve uniform pore size of a porous metal structure because the porous metal structure does not include nickel alloy. CONSTITUTION: A method for manufacturing a porous Fe-Cr-Al based alloy structure is as follows. A preform(10) having pores set according to the pore size of a porous Fe-Cr-Al based alloy structure is prepared. Colloids including Fe-Cr-Al based alloy power having an average grain size of 0.08~0.13μm are spread on the preform with an atomizing method. The preform on which a coating layer(12) is formed is sintered to form a porous metal structure with an oxidized weight increase of 5~20%.

Description

Fe-Cr-Al-based alloy porous body and method of manufacturing the same {Fe-Cr-Al base alloy porous structure and method of manufacturing by the same}

The present invention relates to a Fe-Cr-Al-based alloy porous body and a method for manufacturing the same, and more particularly, to Fe-Cr-Al-based alloy formed by sintering an extremely fine Fe-Cr-Al-based alloy powder coated by electrospray method It relates to a porous body and a method of manufacturing the same.

The metal porous body may be used as a core material of the environment and energy industry, such as electrodes of solar cells and fuel cells, filters for environmental pollution purification, catalyst carriers, high efficiency heat exchange media, and the like. It is also expected to increase rapidly as a key component of environmental and energy technologies such as green car, ultra clean ship, greenhouse gas response industry, large hydrogen power generation, distributed power generation, and high efficiency petroleum substitute fuel production. .

Conventionally, ceramic porous bodies other than such metal porous bodies have been mainly used. However, despite the high temperature safety of the ceramic material, the ceramic porous body has a low thermal shock resistance and a complicated process. In addition, high temperature sintering is required and the price is a problem has emerged as a problem. In order to solve this problem, it is recently replaced by the above-mentioned metal porous body instead of the ceramic porous body, and it is expected that its application field will be expanded as a new area utilizing the metal properties. In particular, the high-performance metal porous foam (foam) can implement a three-dimensional network structure of the sponge form has the advantage that the internal trapping of particulate matter and low back pressure, the utilization thereof is increasing.

In particular, in the collection filter for diesel vehicles, the particulate matter is collected inside, and when a certain amount is collected, the temperature rises to a high temperature of 1000 degrees or more in a regeneration process of burning the particulate matter. However, when a conventional porous metal foam using a nickel-based alloy is used as a filter for collecting particulate matter, since the nickel-based alloy does not have high oxidation resistance at the above-mentioned high temperature, the disadvantage of shortening the lifespan of the porous metal filter including such a nickel group is shortened. have. In the case of the nickel-based alloy, the nickel primer is deposited on the porous polyurethane foam, and an alloying reaction is performed to coat the alloy-based powder thereon.

On the other hand, Fe-Cr-Al-based alloys are excellent in oxidation resistance and excellent in durability even at high temperatures of 1000 degrees or more. Therefore, if the Fe-Cr-Al-based alloy is used as a filter for collecting particulate matter, it exhibits excellent oxidation resistance even at a high temperature of 1000 degrees or more generated during the regeneration process, thereby improving durability. However, in the conventional method for producing a Fe-Cr-Al alloy porous body, a primer layer made of a material such as a nickel-based alloy is essentially required. Accordingly, it is necessary to control the Fe-Cr-Al alloy porous body so that the nickel-based alloy is not contained.

In order to manufacture a Fe-Cr-Al alloy porous body containing no such nickel-based alloy, a metal powder having a size of several tens of micrometers in average particle diameter was conventionally used. However, when the porous body is manufactured using a powder having a size of several tens of micrometers, the pore size may be nonuniform and pore clogging may occur. In addition, the conventional porous body is difficult to form fine pores having a pore size of about 200㎛ or less.

Therefore, the technical problem to be achieved by the present invention is to uniform pore size to prevent pores from clogging, to form fine pores of about 200㎛ or less, the Fe-Cr-Al alloy porous body containing no nickel-based alloy And to provide a method for producing the same.

Fe-Cr-Al-based alloy porous body of the present invention for achieving the above object, Fe by weight; 55-85%, Al; 3-15%, Cr; In the Fe-Cr-Al alloy porous body, which is 10 to 30% and the remaining additional elements are added in less than 1%, the alloy porous body has a fine Fe having a particle size of 0.05 to 0.3 μm and an average particle size of 0.08 to 0.13 μm. It is made by sintering the coating layer coated with -Cr-Al alloy powder in the colloidal state, and the oxidation weight increase rate is greater than 5% and not more than 15%. In this case, the Fe-Cr-Al-based alloy porous body may not include a nickel-based alloy. In addition, the Fe-Cr-Al-based alloy porous body may have a mesh-like structure of sponge.

The method for producing the Fe-Cr-Al-based alloy porous body for achieving the another technical problem is to prepare a preform having pores set according to the pore size of the Fe-Cr-Al-based alloy porous body, the particle size is 0.05 Applying a colloid containing Fe-Cr-Al alloy powder having a particle size of ˜0.3 μm and an average particle size of 0.08 to 0.13 μm on the preform to form a coating layer, and sintering the preform on which the coating layer is formed to increase the oxidative weight increase rate. Forming a Fe—Cr—Al alloy porous body that is greater than 5% and less than or equal to 15%.

In the present invention, the Fe-Cr-Al-based alloy powder may be prepared by an electrolytic explosion in the liquid, the coating layer may be formed by the electrostatic spraying method.

In addition, the preform may be a material that shrinks at a constant rate throughout the preform under conditions of applied temperature and pressure, and the preform is preferably polyurethane.

According to the Fe-Cr-Al-based alloy porous body of the present invention and a method for producing the same, by producing a Fe-Cr-Al-based alloy porous body containing no nickel-based alloy using an extremely fine Fe-Cr-Al-based alloy powder, It is possible to provide a Fe-Cr-Al-based alloy porous body in which the pore size is uniform to prevent the pores from being blocked and to form fine pores of about 200 μm or less.

1 is a partial cross-sectional view for explaining a method for producing a Fe-Cr-Al-based alloy porous body according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below may be modified in various forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art.

In the embodiment of the present invention, by using a very fine Fe-Cr-Al-based alloy powder, by controlling the pore size uniformly, it is possible to prevent the pores are blocked and to form fine pores of about 200㎛ or less, nickel-based alloy It provides a Fe-Cr-Al-based alloy porous body containing no. Here, the very fine Fe-Cr-Al-based alloy powder refers to a powder having a particle size of about 0.05 ~ 0.3㎛, the average particle size of about 0.1㎛. However, the particle size and average particle size may vary within the scope of the present invention. Accordingly, the ultrafine alloy powder of the present invention can be determined to have a particle size of 0.05 to 0.3 µm and an average particle size of 0.08 to 0.13 µm.

<Fe-Cr-Al alloys>

The Fe-Cr-Al alloy has the following composition, and the reason for numerical limitation according to each composition will be described together. At this time,% represents weight%.

(1) iron (Fe): 55-85%

If the Fe content is more than 85%, the heat resistance, corrosion resistance, heat deformation is worse, if less than 55% the strength characteristics are difficult to make the porous metal foam.

(2) aluminum (Al): 3-15%

If the Al content is more than 15%, the workability of the Fe-Cr-Al alloy is worsened. If the Al content is less than 3%, it is difficult to improve the heat resistance and the corrosion resistance.

(3) Chromium (Cr): 10-30%

If the Cr content is less than 10%, it exhibits a relatively high coefficient of thermal expansion and thermal deformation at high temperatures, which is not suitable for use as a high temperature DPF filter material. In addition, when the Cr content is more than 30%, it is difficult to use because a sudden drop in workability appears.

(4) Other additional elements: Y, La, Zr, Ti, Be and the like may be added in less than 1%. In particular, Zr is an element that greatly improves heat resistance and corrosion resistance, and the addition amount is 1% or less, and when Be and Ti are added at 0.01% or less, corrosion and workability may be improved.

1 is a partial cross-sectional view for explaining a method for producing a Fe-Cr-Al-based alloy porous body applied to the present invention. Here, step (a) is a preform (10), step (b) is a coating layer 12 is applied to the preform by the electrospray method, and step (c) is a final Fe-Cr-Al alloy porous body The shape of 14 is shown schematically.

Referring to FIG. 1, first, a preform 10 having a pore P1 set in advance in accordance with a desired Fe-Cr-Al alloy porous body 14, in particular, the size of the pores P3 is manufactured. Preform 10 is preferably a material that is reduced to a constant shrinkage under sintering conditions. Here, the constant shrinkage rate refers to shrinkage at a constant rate throughout the preform 10 under conditions of applied temperature and pressure, and polyurethane is mainly used. In addition, the preform 10 is manufactured according to the shape of the Fe-Cr-Al-based alloy porous body 14, and preferably has a three-dimensional network structure of the sponge form. Thereafter, the colloid containing the ultrafine Fe—Cr—Al alloy powder is formed on the preform 10 by the electrostatic spraying method with a predetermined thickness. Accordingly, the coating layer 12 contains an organic solvent such as alcohol, a dispersant containing a surfactant, and an extremely fine Fe-Cr-Al alloy powder. The preform 10 having the coating layer 12 forms pores P2 smaller than pores P1 in an uncoated state, as shown.

Subsequently, the preform 10 having the coating layer 12 formed thereon is sintered under a pre-set sintering condition of temperature, pressure, and atmosphere gas to prepare the Fe-Cr-Al alloy porous body 14. At this time, the sintering conditions are not particularly limited, for example, the amount of Fe-Cr-Al alloy powder contained in the colloid, the size of the Fe-Cr-Al alloy powder, the melting point of the Fe-Cr-Al alloy It may be determined in consideration of the shrinkage of the preform, the viscosity of the solvent forming the colloid, and the like. Under the sintering conditions as described above, the preform 10 shrinks to form pores P3 of the Fe-Cr-Al alloy porous body, and is sintered to remove the Fe-Cr-Al alloy powder by thermal decomposition.

According to the method for producing the Fe-Cr-Al alloy porous body of the present invention, the Fe-Cr-Al alloy porous body 14 having a pore P3 having an average size of about 200 μm in a 0.1 to 0.3 μm distribution is produced. can do. The reason why the size of the fine pores (P3) can be realized is because the particle size of the Fe-Cr-Al alloy powder used in the present invention is about 0.05 to 0.3 μm and the average particle size is about 0.08 to 0.13 μm. This is because the size of the pores can be easily controlled precisely. In addition, the pore size of the Fe-Cr-Al-based alloy porous body having a pore size of about 200 μm or less can be uniformly controlled.

Since the average size of the pores (P3) may vary depending on the size of the pores (P1) of the preform 10, it depends on the material of the preform (10). In the embodiment of the present invention, a polyurethane is used as the preform 10, but if a preform of another material is used, the size of the pores P3 of the final metal porous body may vary. However, in order for the Fe-Al-Cr metal porous body of the present invention to have excellent characteristics, a pore size of about 200 μm or less is preferable, and such pore size is difficult to be realized by a conventional method, but it is very fine powder as in the present invention. By using this, such a pore size can be sufficiently realized. Moreover, since a porous body can be formed even without a primer layer by the high binding force between particle | grains, the physical property fall of a porous body by a primer layer can be prevented.

Hereinafter, the characteristics of the Fe-Cr-Al alloy porous body of the present invention through the experimental example.

Experiment 1

The average particle size produced by the electroexplosion method in water was 0.1 탆, and Fe by weight%; 82%, Al; 6%, Cr; A Fe-Cr-Al alloy powder composed of 12% was prepared. Separately, a polyurethane foam having a mean pore size (P1 in FIG. 1) of 200 μm was prepared in advance. Thereafter, 40 g of the powder was mixed with 100 ml of ethanol containing 0.5 g of an EFKA 401 dispersant to prepare a colloid. The colloid was placed in a cone-jet electrostatic spraying device (eS-robot, ESR200R2, NanoNC), and then a voltage of 30 kV was applied to the polyurethane foam to a thickness of 50 μm. The colloid-coated polyurethane foam was sintered at 1000 ° C. for 10 hours in a vacuum atmosphere to prepare a Fe-Cr—Al alloy porous body. Subsequently, the pore size and oxidative weight increase rate of the porous body were measured.

Experiment 2

The average particle size produced by the electroexplosion method in water was 0.1 탆, and Fe by weight%; 72%, Al; 12%, Cr; A Fe-Cr-Al alloy powder composed of 16% was prepared. Separately, polyurethane foam having an average pore size of 200 μm was prepared in advance. Thereafter, 40 g of the powder was mixed with 100 ml of ethanol containing 0.5 g of an EFKA 401 dispersant to prepare a colloid. The colloid was put into a cone-jet electrostatic spraying device, and then a voltage of 30 kV was applied to the polyurethane foam in a thickness of 50 μm. The colloid-coated polyurethane foam was sintered at 1000 ° C. for 10 hours in a vacuum atmosphere to prepare a Fe-Cr—Al alloy porous body. Subsequently, the pore size and oxidative weight increase rate of the alloy porous body were measured.

Comparative Experiment 1

The average particle size produced by the electroexplosion method in water was 0.1 탆, and Fe by weight%; 86%, Al; 1%, Cr; A Fe-Cr-Al alloy powder composed of 13% was prepared. Separately, polyurethane foam having an average pore size of 200 μm was prepared in advance. Thereafter, 40 g of the powder was mixed with 100 ml of ethanol containing 0.5 g of an EFKA 401 dispersant to prepare a colloid. The colloid was put into a cone-jet electrostatic spraying device, and then a voltage of 30 kV was applied to the polyurethane foam in a thickness of 50 μm. The colloid-coated polyurethane foam was sintered at 1000 ° C. for 10 hours in a vacuum atmosphere to prepare a Fe-Cr—Al alloy porous body. Subsequently, the pore size and oxidative weight increase rate of the alloy porous body were measured.

Comparative Experiment 2

The average particle size produced by the electroexplosion method in water was 0.2 탆, and Fe by weight%; 72%, Al; An Fe-Cr-Al alloy powder composed of 16% and Cr 7% was prepared. Separately, polyurethane foam having an average pore size of 300 μm was prepared in advance. Thereafter, 40 g of the powder was mixed with 100 ml of ethanol containing 0.5 g of an EFKA 401 dispersant to prepare a colloid. The colloid was put into a cone-jet electrostatic spraying device, and then a voltage of 30 kV was applied to the polyurethane foam in a thickness of 50 μm. The colloid-coated polyurethane foam was sintered at 1000 ° C. for 10 hours in a vacuum atmosphere to prepare a Fe-Cr—Al alloy porous body. Subsequently, the pore size and oxidative weight increase rate of the alloy porous body were measured.

Comparative Experiment 3

The average particle size prepared by atomizing was 10 μm, and Fe by weight%; 82%, Al; 6%, Cr; A Fe-Cr-Al alloy powder composed of 12% was prepared. Separately, polyurethane foam having an average pore size of 450 μm was prepared in advance. At this time, the average pore size is larger than the pores (P1) of the test material because the Fe-Cr-Al-based alloy powder here is much larger than the Fe-Cr-Al-based alloy powder of the test material and was inevitably determined. Subsequently, Ni was electrodeposited onto the polyurethane foam by physical vapor deposition, followed by heat treatment at 800 ° C. for 8 hours in a reducing atmosphere to form a Ni primer layer on the polyurethane foam. Thereafter, a 1.0% aqueous solution of polyvinylpyrrolidone as a binder was applied to the Ni primer layer with a thickness of 0.1 μm by spraying. The alloy powder was sprayed onto the polyurethane foam coated with the binder and mixed with the binder, followed by sintering at 1000 ° C. for 10 hours in a vacuum atmosphere to prepare a porous body. Finally, the pore size and oxidative weight increase rate of the porous body were measured.

Comparative Experiment 4

The average particle size prepared by atomizing was 10 μm, and Fe by weight%; 72%, Al; 12%, Cr; A Fe-Cr-Al alloy powder composed of 16% was prepared. Separately, polyurethane foam having an average pore size of 450 μm was prepared in advance. At this time, the average pore size is larger than the pores (P1) of the test material because the Fe-Cr-Al-based alloy powder here is much larger than the Fe-Cr-Al-based alloy powder of the test material and was inevitably determined. Subsequently, Ni was electrodeposited onto the polyurethane foam by physical vapor deposition, followed by heat treatment at 800 ° C. for 8 hours in a reducing atmosphere to form a Ni primer layer on the polyurethane foam. A 1.0% aqueous solution of polyvinylpyrrolidone as a binder was applied to the Ni primer layer by a spray method at a thickness of 0.1 μm. The alloy powder was sprayed onto the polyurethane foam coated with the binder, mixed with the binder, and then sintered at 1000 ° C. for 10 hours in a vacuum atmosphere to prepare a porous body. Finally, the pore size and oxidative weight increase rate of the porous body were measured.

Table 1 shows the particle size, pore size and oxidation weight of the Fe-Cr-Al alloy porous body prepared by Experimental Materials 1 and 2 to which the examples of the present invention are applied and Comparative Experimental Materials 1 to 4 for comparison with the experimental materials. The growth rates are presented separately. At this time, the particle size was measured using a particle size analyzer (PSA), the pore size was measured using a scanning electron microscope (SEM). In addition, the oxidative weight increase rate was measured as the weight increase rate of the specimen in a state in which the temperature was raised to 1000 degrees at a temperature increase rate of 5 degrees per minute in air, and then cooled at 1000 degrees for 10 hours. In the case of the porous metal body, the oxidation weight increase rate is measured in order to evaluate the oxidation characteristics because the surface area exposed at high temperature is very large.

division Average particle size
(Μm) Average pore size
(Μm) Oxidation weight increase rate
(%) Experiment 1 0.1 200 15 Experiment 2 0.1 200 15 Comparative Experiment 1 0.1 200 19 Comparative Experiment 2 0.2 300 19 Comparative Experiment 3 10 450 20 Comparative Experiment 4 10 450 20

In Table 1, Test Materials 1 and 2 are porous bodies prepared according to the Examples of the present invention, Comparative Test Materials 1 and 2 are porous bodies prepared by varying the content of Test Materials 1, 2 and Al, Comparative Test Material 3 And 4 shows the porous body containing the Ni primer layer manufactured by the conventional method.

According to Table 1, Comparative Experiment 1 used the same fine particle size and manufacturing method as the experimental materials, but contains only 1% Al in the alloy. This is less than 3 to 15% of the Al content in the experimental example of the present invention, and because of this, the average pore size was the same, but the oxidation resistance was lower than the oxidation weight increase rate showed a larger value than the experimental materials of the present invention.

Comparative Test Material 2 used 0.2 µm fine powder larger than 0.08 to 0.13 µm, which is an average particle size of the present invention, and 16% Al was added to the alloy. First, the average particle size of the fine powder obtained by submerged electroexplosion was 0.2 µm, and a porous body having an average pore size of 0.2 µm could not be obtained. In addition, since Al is added in excess of 3 to 15% of the Al content in the experimental example of the present invention, peeling of the aluminum oxide film for enhancing oxidation resistance occurs, resulting in an increase in the oxidative weight increase rate compared to Test Materials 1 and 2 of the present application. It was.

Comparative Test Materials 3 and 4 were prepared by a fine spraying method, powder having an average particle size of 10 μm was used, and a nickel-based alloy was used as a primer layer. In these cases, it was found that the average pore size and the oxidative weight increase rate were larger than those of the Fe-Cr-Al alloy porous bodies of Experimental Materials 1 and 2 of the present invention using the ultra fine powder. Experimental materials 1 and 2 of the present invention have a small particle size of the metal powder constituting the porous metal body, thereby reducing the average pore size of the porous body. Accordingly, the pores of the test materials of the present invention is significantly larger than the surface area in contact with oxygen compared to the comparative test materials 3 and 4.

Nevertheless, the reason why the oxidative weight increase rate of the test materials 1 and 2 has a smaller value is that, unlike the comparative test materials 3 and 4, Ni alloy powder having low oxidation resistance was not used. In other words, Test Samples 1 and 2 of the present invention, unlike Comparative Test Samples 3 and 4, did not use a primer layer of a nickel-based alloy that does not have high oxidation resistance at high temperatures, and because powder particles had a relatively small particle size, As the binding force between the particles increased, the oxidation resistance of the porous body increased and the average pore size decreased.

According to the present invention, when a very fine powder having a particle size of about 0.05 to 0.3 µm and an average particle size of 0.08 to 0.13 µm is used, it does not contain a nickel-based alloy used as a primer layer and has an average pore size of 200 µm or less. A metal porous body having a working process can be produced. By controlling the particle size of the metal powder, the pore size of the preform, the process conditions, etc., it is apparent to those skilled in the art that the average pore size is 200 µm or less and the oxidation weight increase rate can be reduced to 15% or less. Will do.

It is preferable that the Fe-Al-Cr-based metal porous body of the present invention has an oxidation weight increase rate of more than 5% and 15% or less. This is in consideration of the physical properties that the metal porous body can be used as a practical core material of the industry. The metal porous body of the present invention is expected to have wider surface area in contact with oxygen and increase oxidation resistance at high temperature, and thus, its utilization as a core component of environmental and energy technology is expected to be increased.

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 many variations and modifications may be made without departing from the scope of the present invention. It is possible.

10; Preform
12; Coating layer
14; Metal porous body

Claims (8)

Fe by weight; 55-85%, Al; 3-15%, Cr; In the Fe-Cr-Al-based alloy porous body which is 10 to 30% and the remaining additional elements are added in less than 1%,
The alloy porous body is made by sintering a coating layer coated with a very fine Fe-Cr-Al alloy powder having a particle size of 0.05 to 0.3 μm and an average particle size of 0.08 to 0.13 μm in a colloidal state, and an oxidative weight increase rate of more than 5%. A large Fe-Cr-Al alloy porous body of 20% or less. The Fe-Cr-Al-based alloy porous body according to claim 1, wherein the Fe-Cr-Al-based alloy porous body does not contain a nickel-based alloy. The Fe-Cr-Al-based alloy porous body according to claim 1, wherein the Fe-Cr-Al-based alloy porous body has a sponge-like mesh structure. Preparing a preform having pores set according to the pore size of the Fe-Cr-Al alloy porous body;
Forming a coating layer by applying a colloid containing Fe-Cr-Al alloy powder having a particle size of 0.05 to 0.3 μm and an average particle size of 0.08 to 0.13 μm on the preform; And
Sintering the preform on which the coating layer is formed to form a Fe-Cr-Al-based alloy porous body having an oxidation weight increase rate of greater than 5% and 20% or less. 5. The method of claim 4, wherein the Fe—Cr—Al alloy powder is prepared by an electroexplosion method in a liquid. The method of claim 4, wherein the coating layer is formed by an electrospray method. 5. The method of claim 4, wherein the preform is made of a material that shrinks at a constant rate over the entire preform under conditions of applied temperature and pressure. 6. The method of manufacturing a Fe-Cr-Al alloy porous body according to claim 7, wherein the preform is polyurethane.

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