WO2014002777A1

WO2014002777A1 - Process for producing porous metal body and porous metal body

Info

Publication number: WO2014002777A1
Application number: PCT/JP2013/066293
Authority: WO
Inventors: 西村　淳一; 細江　晃久; 奥野　一樹; 弘太郎木村; 健吾後藤; 英彰境田
Original assignee: 住友電気工業株式会社
Priority date: 2012-06-29
Filing date: 2013-06-13
Publication date: 2014-01-03
Also published as: JP2015165036A

Abstract

The present invention provides a process for producing a porous metal body (such as a porous aluminum body) which is composed of a dense skeleton that has fewer pinholes and which is rarely contaminated with nitride or other impurities and is therefore not susceptible to embrittlement. This process comprises: employing, as a substrate, a flat plate composed of a resin-made skeleton having a three-dimensional network structure; forming a conductive layer on the surface of the resin-made skeleton; forming a metal film on the conductive layer by direct-current sputtering while bringing the plate into thermal contact with a drum cooled with a coolant; and removing the resin-made skeleton by heating after the formation of the metal film to produce a porous metal body.

Description

Method for producing porous metal body and porous metal body

The present invention relates to a method for producing a metal porous body by forming a metal film on a resin surface by a metal sputtering method, and in particular, a metal porous body that can be suitably used for applications such as various filters and battery electrodes, and the production thereof. Regarding the method.

Metal porous bodies having a three-dimensional network structure are used in various fields such as various filters, catalyst carriers, and battery electrodes. For example, cermet made of nickel (manufactured by Sumitomo Electric Industries, Ltd .: registered trademark) is used as an electrode material for batteries such as nickel metal hydride batteries and nickel cadmium batteries. Celmet is a metal porous body having continuous air holes, and has a feature of high porosity (90% or more) compared to other porous bodies such as a metal nonwoven fabric. This can be obtained by forming a nickel layer on the surface of the porous resin skeleton having continuous air holes such as urethane foam, then heat-treating it to decompose the foamed resin molding, and further reducing the nickel. The formation of the nickel layer is performed by depositing nickel by electroplating after applying carbon powder or the like to the surface of the skeleton of the foamed resin molded body and conducting a conductive treatment.

Aluminum also has excellent features such as conductivity, corrosion resistance, and light weight. In battery applications, for example, a positive electrode of a lithium ion battery in which an active material such as lithium cobaltate is applied to the surface of an aluminum foil is used. In order to improve the capacity of the positive electrode, it is conceivable that aluminum is made porous to increase the surface area and the aluminum is filled with an active material. This is because the active material can be used even if the electrode is thickened, and the active material utilization rate per unit area is improved.

As a method for producing a porous aluminum body, Patent Document 1 discloses that a metal aluminum layer having a thickness of 2 to 20 μm is formed by subjecting a three-dimensional net-like plastic substrate having an internal communication space to aluminum vapor deposition by an arc ion plating method. A method is described. In Patent Document 2, a film made of a metal (such as copper) that forms a eutectic alloy below the melting point of aluminum is formed on the skeleton of a foamed resin molding having a three-dimensional network structure, and then an aluminum paste is applied. There is a method of obtaining a porous metal body by performing a heat treatment at a temperature of 550 ° C. or more and 750 ° C. or less in a non-oxidizing atmosphere to eliminate organic components (foamed resin) and to sinter aluminum powder (sintering method). Are listed.

Japanese Patent No. 3427435 Japanese Patent No. 3568052

It is known that a vapor phase deposition method such as an arc ion plating method forms a metal film with less impurities and higher purity than a sintering method or the like. In addition, a dense film with few defects such as pinholes can be obtained.

However, the vapor deposition method is suitable for forming a film on a flat substrate, but it is difficult to form a film inside the fine pores of the porous body. Here, the sputtering method in which film formation is performed under a relatively high pressure of about 1 Pa to 10 ² Pa has a shorter mean free process than the vacuum evaporation method in which film formation is performed at a high vacuum level of about 10 ⁻⁴ Pa. It is known as a technique that is easy to wrap around and relatively easy to form a film on the shadowed part.

On the other hand, when a resin is used for the substrate, decomposition occurs in part of the substrate due to the influence of heat and plasma. In particular, when a film is formed for a long time in order to form a thick film, the influence of heat becomes large, and the generation amount of decomposition gas increases remarkably. The generated decomposition gas is released into the film formation atmosphere, so that the components are taken into the film during film formation, which affects the purity of the film.

In particular, in the arc ion plating method or sputtering method using plasma, the decomposition gas is further decomposed in the plasma, and the electrons related to the chemical bond are excited and activated, so that they are easily taken in as impurities in the film. .

On the other hand, the base resin is decomposed and removed by heat treatment after film formation. For this purpose, polyurethane or melamine resin (melamine-formaldehyde resin) is suitable. A method of removing aluminum after forming the resin base. So the resin is indispensable.

However, since polyurethane and melamine resin have characteristics that are easily decomposed by heat, they are easily affected by heat and plasma, and the amount of decomposition gas released during film formation increases.

Furthermore, metals such as aluminum are easily oxidized and rich in reactivity, reacting with decomposition gas from polyurethane and melamine resin, and nitriding, oxidation, and carbonization of metals such as aluminum occur and become brittle. In addition, if the substrate is made of a resin having high heat resistance in order to suppress the release amount of decomposition gas, it is necessary to increase the heating temperature when removing the substrate, and metals such as aluminum are likely to be oxidized. Become. In order to suppress the oxidation, it is necessary to prevent oxygen from being mixed in the atmosphere, but the burden on the facility is increased in adjusting the atmosphere.

For example, when an aluminum porous body having a large amount of impurities such as nitride is used for a current collector for a lithium secondary battery, a lithium ion capacitor, and an electric double layer capacitor, the active material is packed and pressed. The skeleton constituting the aluminum porous body is likely to be broken, and there arises a problem that the retention of the active material and the current collecting property are impaired.

The present invention relates to a method for producing a porous metal body such as an aluminum porous body that is formed from a dense skeleton that has relatively no pinholes and that is less likely to cause embrittlement and that is less contaminated with impurities such as nitrides. The purpose is to provide.

The present invention provides a conductive treatment step in which a flat plate made of a resin and formed from a three-dimensional network skeleton is used as a base, and a conductive layer is formed on the surface of the skeleton, and the flat plate is brought into thermal contact with a cooling drum. A porous metal body manufacturing method comprising: a film forming step of forming a metal film on the conductive layer by a direct current sputtering method; and a step of removing the substrate by heating after the film forming step.

By using the direct current sputtering method in the film forming process, it is possible to obtain a dense metal porous body with less pinholes and higher purity than the sintering method. In the sintering method, the powder particles are loosely sintered without any special pressure, so that a gap is easily formed between the particles.

The sputtering method uses glow discharge which is non-equilibrium plasma. For this reason, compared with the arc ion plating method using arc discharge, the gas temperature related to plasma such as argon gas is lowered, and a resin having a three-dimensional network skeleton serving as a substrate (hereinafter referred to as a resin molding). ) Can be reduced, and generation of decomposition gas from the resin molded product can be suppressed.

In addition, in the direct current sputtering method, positive ions generated by glow discharge plasma such as argon gas mainly collide with the target, and the reverse sputtering phenomenon in the resin molded body hardly occurs, so compared with the high frequency sputtering method using alternating current. Thus, the direct burden of plasma on the resin molding is reduced. Thereby, generation | occurrence | production of the decomposition gas from a resin molding can be suppressed.

Furthermore, in the present invention, in the film forming step, the thermal burden on the resin molded body is greatly reduced by cooling the flat plate by bringing it into thermal contact with a cooling drum. Here, the term “thermal contact” means that the surface of the resin molded body whose shape is a flat plate, that is, either the upper surface or the lower surface in the thickness direction of the resin molded body, and the surface of the cooling drum are almost the same. It is in contact over the entire surface and heat is conducted between them. It is not necessary that 100% of the surface of the resin molded body is in contact with the cooling drum, and at least 75% or more, preferably 90% or more of the surface of the resin molded body may be in contact.

As described above, in the metal film formation process, decomposition of the resin serving as the substrate can be suppressed, and mixing of carbon, nitrogen, and oxygen into the metal film can be suppressed.

In addition, in the present invention, one or a mixture of polyurethane resin and melamine resin is used as the resin.

Since these resins are excellent in thermal decomposability, the resin molded body can be removed after the metal film is formed without oxidizing the metal film more than necessary.

When the metal porous body is an aluminum porous body, the effects of the present invention are further manifested.

The metal porous body obtained by the present invention is a metal porous body having continuous air holes formed from a three-dimensional network skeleton, and having an average pore diameter of 100 μm or more and 500 μm or less. Takes a flat plate shape, the flat plate has a thickness of 0.5 mm or more and 5 mm or less, the skeleton has a hollow structure, and the wall forming the hollow structure has a thickness of 10 μm or more, the flat plate surface It is a metal porous body whose thickness of the said wall in the center position of the said flat plate-shaped thickness is 75% or more with respect to the thickness of the said wall in a position.

The metal porous body of the present invention takes a flat plate shape, and the thickness of the metal skeleton at the center in the thickness direction of the flat plate shape is thinner than the thickness of the metal skeleton at the upper and lower surface positions in the thickness direction of the flat plate shape. However, the metal porous body of the present invention has a feature that the difference is small.

Thereby, for example, when the porous metal body according to the present invention is an aluminum porous body and used as an electrode of a lithium secondary battery or an electric double layer capacitor, the difference in electron conductivity between the inside and outside of the electrode is reduced, and the current collecting characteristics The difference is smaller. Moreover, when manufacturing these electrodes, the active material or the like is usually packed in the aluminum porous body and then compressed in the thickness direction of the flat plate shape, but the difference in the degree of compression inside and outside the electrode And a relatively uniform electrode can be formed. Thereby, it can be suppressed that the active material or the like is clogged too much at the central portion in the thickness direction of the electrode, the penetration of the electrolytic solution or the like becomes worse, and the charge / discharge characteristics become worse.

According to the present invention, it is possible to provide a metal porous body formed from a dense skeleton relatively free of pinholes and the like, in which impurities such as nitrides are hardly mixed and brittleness hardly occurs. it can.

It is a cross-sectional schematic diagram explaining the manufacturing process of the metal porous body by this invention. It is a surface enlarged photograph which shows the structure of the urethane foam resin as an example of a resin molding. It is a figure explaining an example of the electrically conductive process process to the resin molding surface by a conductive paint. It is a figure explaining an example of the metal film formation process by direct current | flow sputtering method.

Hereinafter, embodiments of the present invention will be described by using a method for producing a metal porous body and a metal porous body produced according to the present invention as representative examples with reference to the drawings as appropriate.

(Manufacturing process of metal porous body)
FIG. 1 schematically shows a state where a metal porous body is manufactured by forming a metal film 3 after forming a conductive layer 2 using a resin molded body 1 as a core, and finally removing the core. It is. The overall flow of the manufacturing process will be described with reference to FIG.
First, the resin molded body 1 is prepared (FIG. 1A).
Next, a thin conductive layer 2 is formed on the surface of the resin molded body 1 (FIG. 1B). With this conductive layer 2, the subsequent metal film 3 can be efficiently formed by DC sputtering. In addition, the conductive layer 2 can function as a protective layer that suppresses the resin molded body 1 from being decomposed by being directly exposed to plasma in the formation of the metal film 3. Furthermore, the conductive layer 2 has a relatively high thermal conductivity due to its electronic conductivity, and can improve the cooling ability of the resin molded body 1 compared to the case of a single resin, and the thermal decomposition of the resin molded body when forming the metal film 3 Can be suppressed.
Subsequently, a metal film is formed on the resin molded body by a direct current sputtering method (FIG. 1C). Thus, a metal structure in which the metal film 3 is formed on the surface of the resin molded body is obtained.
Finally, the resin molded body 1 is removed. A metal porous body in which only the metal layer remains can be obtained by disassembling the resin molded body 1 to disappear (FIG. 1 (d)). Hereinafter, each step will be described in order.

(Preparation of resin molding)
A porous resin molded body formed of a three-dimensional network skeleton and having continuous air holes is prepared. As the resin molded body, a resin molded body having an arbitrary shape can be selected as long as it has continuous pores (continuous vent holes). For example, those formed by foaming a resin or those having a shape like a nonwoven fabric entangled with a fibrous resin can be used. The resin molded body preferably has a porosity of 80% to 98% and a pore diameter of 100 μm to 500 μm.

The material of the resin molding is preferably polyurethane or melamine resin. Here, in the resin molded body in which the resin is foamed, the foamed urethane and the foamed melamine resin have high porosity, and have excellent porosity and thermal decomposability. It can be preferably used. Further, urethane foam is preferable in terms of the uniformity of pores and the ease of obtaining a product having a small pore diameter.

Resin moldings often have residues such as foaming agents and unreacted monomers in the foam production process, and it is preferable to perform a cleaning treatment for the subsequent steps. As an example of the resin molded product, FIG. 2 shows a product obtained by washing urethane foam as a pretreatment. The resin molded body forms a three-dimensional network as a skeleton, thereby forming continuous pores as a whole. The urethane skeleton has a substantially triangular shape in a cross section perpendicular to the extending direction. Here, the porosity is defined by the following equation.
Porosity = (1− (weight of porous material [g] / (volume of porous material [cm ³ ] × material density))) × 100 [%]
Also, the pore diameter is averaged by enlarging the resin molded body surface with a micrograph, etc., and counting the number of pores per inch (25.4 mm) as the number of cells, and the average pore diameter = 25.4 mm / cell number. Find the correct value.

(Conductive layer formation on the surface of resin molding)
A conductive layer is formed on the surface of the resin molding. There is no particular limitation as long as it is a treatment that can provide a conductive layer on the surface of the resin molded body. Formation of a conductive metal layer such as nickel and copper by electroless plating, aluminum by vapor deposition or sputtering, etc. Any method can be selected, such as the formation of the conductive metal layer and the application of a conductive paint containing conductive particles such as carbon.
As an example of forming the conductive layer, a method for forming a conductive layer by sputtering of aluminum and a method for forming a conductive layer by applying and drying a paint using carbon as conductive particles on the surface of a resin molded body are described below. State.

-Formation of aluminum layer by sputtering-
The aluminum layer formation by the sputtering method is not limited as long as aluminum is used as a target, and may be performed according to a conventional method. For example, after attaching a resin molded body to a substrate holder, an inert gas is introduced into the substrate and a target (aluminum) while generating plasma by high-frequency or direct current glow discharge between the holder and the target (aluminum). The aluminum layer is formed by causing the aluminum particles to collide with aluminum and depositing the repelled aluminum particles on the surface of the resin molded body.

The sputtering method is preferably performed at a temperature at which the resin molded body does not dissolve, and specifically, it may be performed at about 100 to 200 ° C., preferably about 120 to 180 ° C. Here, a sputtering method using direct current is preferable from the viewpoint of suppressing the decomposition of the resin molded body by plasma, but even when a high frequency is used, the decomposition by the plasma can be suppressed by controlling the applied voltage. Is possible.

-Carbon coating-
Prepare carbon paint as conductive paint. The carbon paint preferably contains carbon particles, a binder, a dispersant, and a dispersion medium. In order to uniformly apply the carbon particles, the carbon paint needs to maintain a uniform suspended state. For this reason, the carbon paint (hereinafter referred to as suspension) is preferably maintained at 20 ° C. to 40 ° C. The reason is that when the temperature of the suspension is less than 20 ° C., the uniform suspension state is lost, and only the binder is concentrated on the surface of the three-dimensional network structure of the resin molding to form a layer. Because it does. In this case, the applied carbon particle layer is easy to peel off, and it is difficult to form a tightly adhered metal film.

On the other hand, when the temperature of the suspension exceeds 40 ° C., the evaporation amount of the dispersant and the dispersion medium is large, and the suspension is concentrated as the coating treatment time elapses, and the coating amount of carbon tends to fluctuate. The average particle size of the carbon particles is 0.01 to 5 μm, preferably 0.01 to 0.5 μm, as measured with a particle size distribution meter. When the particle size is large, the pores of the resin molded body are clogged, and a metal film is not formed at that portion. Moreover, it becomes a factor which inhibits formation of a smooth metal film. On the other hand, if the particle size is too small, it is difficult to ensure sufficient conductivity, and the metal film formation in the next process cannot be performed smoothly.

Application of the carbon particles to the resin molded body can be performed by immersing the target resin molded body in the carbon paint and performing squeezing and drying. FIG. 3 schematically shows an example of a configuration of a processing apparatus for making a resin porous body (hereinafter referred to as a band-shaped resin) conductive by making a resin molded body, which is a flat plate, long as a band, as an example of a practical manufacturing process. FIG. As shown in the figure, this apparatus includes a supply bobbin 12 for supplying a belt-shaped resin 11, a tank 15 containing a conductive paint suspension 14, a pair of squeezing rolls 17 disposed above the tank 15, A plurality of hot air nozzles 16 provided opposite to the upper and lower surfaces of the belt-shaped resin 11 to be wound, and a winding bobbin 18 for winding the belt-shaped resin 11 after processing. Further, a deflector roll 13 for guiding the belt-shaped resin 11 is appropriately disposed.

In the apparatus configured as described above, the strip-shaped resin 11 is unwound from the supply bobbin 12, guided by the deflector roll 13, and immersed in the suspension in the tank 15. The strip-shaped resin 11 immersed in the suspension 14 in the tank 15 changes its direction upward and travels between the squeeze rolls 17 above the liquid level of the suspension 14. At this time, the distance between the squeezing rolls 17 is smaller than the thickness of the strip-shaped resin 11, and the strip-shaped resin 11 is compressed. Therefore, the excess suspension impregnated in the belt-shaped resin 11 is squeezed out and returned to the tank 15.

Subsequently, the strip-shaped resin 11 changes the traveling direction again. Here, the suspension dispersion medium and the like are removed by hot air jetted by the hot air nozzle 16 composed of a plurality of nozzles, and the belt-like resin 11 is wound around the winding bobbin 18 after sufficiently drying. The temperature of the hot air ejected from the hot air nozzle 16 is preferably in the range of 40 ° C to 80 ° C. When the apparatus as described above is used, the conductive layer can be formed automatically and continuously, and a skeleton having a network structure without clogging and having a uniform conductive layer is formed. Therefore, the metal film can be smoothly formed by the direct current sputtering method in the next step.

-Formation of metal film-
FIG. 4 shows an overview of a direct current sputtering film forming apparatus. The DC sputtering deposition apparatus is in electrical and thermal contact with a chamber 100 that maintains a vacuum and a reduced pressure state, a cathode 106 and a target 105 that are cooled by a refrigerant, and a strip-shaped resin 101 on which a conductive layer is formed. A first drum (cooling drum) 102, a second drum 103 for unwinding the strip-shaped resin 101 in a roll-to-roll system, and a third drum 104 for winding the strip-shaped resin 101. The first drum functions as an anode, but is connected to the ground, and glow discharge plasma is generated by applying a DC voltage to the cathode. The chamber 100 is provided with an exhaust system 107 for evacuating the system, a gas piping system 108 for introducing an inert gas (for example, argon (Ar) gas) for generating plasma, and the like. In the vicinity of the first drum 102, a protection plate 109 is installed so that plasma is not generated except in the portion of the first drum that faces the cathode. A shutter 110 is provided between the first drum and the cathode. The shutter 110 is closed at the start of glow discharge, and impurities on the target surface can be removed. During actual film formation, the shutter 110 is opened.

It is important to cool the first drum with a refrigerant such as water or a fluorine-based inert liquid (for example, fluorinate). The material is preferably a metal having high thermal conductivity such as copper. The temperature of the surface of the first drum is controlled so that thermal decomposition of the strip-shaped resin 101 is suppressed. The temperature of the surface of the first drum is also affected by the thickness of the strip-shaped resin 101 and the thickness of the metal film to be formed. That is, if the strip-shaped resin 101 is thick, the thermal conductivity is deteriorated, so the surface temperature of the first drum needs to be further lowered. If a thick metal film is to be formed, the film formation time becomes longer, and the time for the strip-shaped resin 101 to be exposed to plasma becomes longer. Therefore, the temperature of the first drum needs to be lowered.

In order to increase the deposition rate, it is necessary to increase the electric power supplied between the cathode and the anode. Even in this case, it is necessary to further reduce the surface temperature of the first drum. Here, it is important to control the surface temperature of the first drum so that the surface temperature of the belt-like resin 101 does not exceed 100 ° C.

Next, a method for forming a metal film will be described. The inside of the chamber 100 is once evacuated to 10 ⁻⁴ Pa. Thereafter, Ar gas is introduced into the chamber 100 until the pressure reaches 1 Pa to 10 ² Pa. After the inside of the chamber reaches a certain pressure, a predetermined DC voltage is applied between the anode and the cathode to generate plasma by glow discharge. This DC voltage is usually adjusted to about several hundred volts to about 5 kV. The generated current value is about 10 ⁻¹ to 10 ² A / m ² , and the film formation rate can be increased by setting this current value high. A metal film is formed on the belt-shaped resin 101 by gasifying the raw material from the target by the generated plasma. When the film thickness of the metal film at the surface position of the strip-shaped resin 101 having a flat plate shape is 10 μm, it takes about 1 to 3 hours to form the metal film with the cathode of the first drum. It moves on the opposing surface. Thereby, a metal film is formed on one surface of the belt-like resin 101.

After the formation of the metal film on one surface of the belt-shaped resin 101 is completed, the belt-shaped resin 101 is rewinded, the surface on which the film is not formed is turned outside, and the metal film is formed again in the same manner as described above. Thus, a band-shaped metal structure in which a metal film is formed on the band-shaped resin molded body is created.

Finally, the strip-shaped metal structure is heated to thermally decompose and remove the resin molded body. The heating condition may be air or an inert atmosphere such as nitrogen gas. The heating temperature may be equal to or higher than the thermal decomposition temperature of polyurethane or melamine resin as the material of the resin molded body, but is usually 400 ° C. or higher and 650 ° C. or lower. When the temperature exceeds 650 ° C., the oxidation of the metal film is promoted.

Next, the present invention will be described in more detail based on examples. The examples are not intended to limit the scope of the invention.

(Example 1)
A porous metal body made of aluminum is prepared. The film forming apparatus shown in FIG. 4 is used. The distance between the target and the first drum is set to 10 cm. An aluminum plate is used for the target. For the resin molded body, polyurethane having a foamed thickness of 1 mm, a width of 10 cm, and an average pore diameter of 300 μm is used.
Carbon is applied to the resin molded body. Carbon particles having an average particle size of 0.1 μm to 0.3 μm are used. The thickness of the carbon coating layer is about 1 μm.
The surface temperature of the first drum is cooled to −10 ° C. by circulating the fluorinated inert liquid cooled by the cooling device. The belt-shaped resin is moved at a constant speed while being in close contact with the first drum by roll-to-roll.
Ar gas is controlled in the chamber so that the pressure becomes 1 Pa. Further, a glow discharge plasma is generated by applying a DC voltage of 1 kV between the anode and the cathode. The current value at this time is about 2A. The surface temperature of the belt-like resin is 75 ° C. as measured by a radiation thermometer. The feeding speed of the belt-shaped resin was set to a speed for moving the half surface of the first drum (diameter: 50 cm) facing the cathode in 2 hours. After the formation of the metal film on one side of the belt-shaped resin is completed, the belt-shaped resin is re-rolled, the surface on which the film is not formed is turned outside, and the metal film is formed again in the same manner as described above.
The obtained metal structure is heated at 500 ° C. for 15 minutes in the air to remove the resin molded body. The thickness of the obtained porous aluminum body is 1 mm, the thickness of the aluminum film at the surface position is 15 μm, and the thickness of the central aluminum film in the thickness direction is 12 μm.
The compression test of the obtained aluminum porous body is performed. The aluminum porous body is cut into a 10 cm square and compressed to half the thickness in the thickness direction. No cracks occur in the aluminum skeleton constituting the aluminum porous body. Further, the difference in the average pore diameter after compression between the surface layer of the porous aluminum body and the central portion in the thickness direction is suppressed to about 90%.

(Example 2)

Using nickel as the metal, a nickel porous body is produced in the same manner as in Example 1.
The thickness of the nickel film at the surface position of the obtained nickel porous body is 15 μm, and the thickness of the nickel film at the center in the thickness direction is 12 μm.
The compression test of the obtained nickel porous body is performed. A nickel porous body is cut into a 10 cm square and compressed to half the thickness in the thickness direction. The nickel skeleton constituting the nickel porous body is not cracked. Further, the difference in the average pore diameter after compression between the surface layer of the nickel porous body and the central portion in the thickness direction is suppressed to about 90%.
(Comparative Example 1)

A porous aluminum body is produced in the same manner as in Example 1 except that the first drum is not cooled.
The thickness of the obtained aluminum porous body is thinner than the initial thickness of the resin molded body, and the pore size distribution also varies widely.
The compression test of the obtained aluminum porous body is performed. The aluminum porous body is cut into a 10 cm square and compressed to half the thickness in the thickness direction. It can be seen that the aluminum skeleton constituting the aluminum porous body is cracked and cut, resulting in embrittlement.

The porous metal body produced according to the present invention can be suitably used as a porous metal body in applications such as various filters and battery electrodes.

DESCRIPTION OF SYMBOLS 1 Resin molding 2 Conductive layer 3 Metal film 11 Band-shaped resin 12 Supply bobbin 13 Deflector roll 14 Conductive paint suspension 15 Tank 16 Hot air nozzle 17 Drawing roll 18 Winding bobbin 100 Chamber 101 Band-shaped resin 102 1st drum (cooling) Drum)
103 Second drum 104 Third drum 105 Target 106 Cathode 107 Exhaust system 108 Gas piping system 109 Guard plate 110 Shutter

Claims

Made of resin, with a base plate formed from a three-dimensional network skeleton,
A conductive treatment step of forming a conductive layer on the surface of the skeleton;
A film forming step of thermally contacting the flat plate with a cooling drum and forming a metal film on the conductive layer by a direct current sputtering method;
Removing the substrate by heating after the film-forming step;
A method for producing a porous metal body.
The method for producing a porous metal body according to claim 1, wherein the resin is one or a mixture of polyurethane resin and melamine resin.
The method for producing a porous metal body according to claim 1 or 2, wherein the porous metal body is an aluminum porous body.
A porous metal body having continuous air holes formed from a three-dimensional network skeleton, wherein the average air hole diameter of the continuous air holes is 100 μm or more and 500 μm or less,
The metal porous body takes a flat plate shape, and the thickness of the flat plate shape is 0.5 mm or more and 5 mm or less,
The skeleton has a hollow structure, and a wall forming the hollow structure has a thickness of 10 μm or more,
The wall thickness at the central position of the flat plate thickness is 75% or more with respect to the thickness of the wall at the flat plate surface position.
Metal porous body.