KR20150120962A - Porous aluminum object, heat transfer material, and heat exchanger - Google Patents

Abstract

Provided is an aluminum porous body which has a very large specific surface area, is excellent in heat exchange efficiency, and can be used as a thermoelectric material having a small gas pressure loss. An aluminum porous body comprising aluminum as a main component, wherein the aluminum porous body has an aluminum porous body having a three-dimensional mesh-like structure and having a specific surface area (Y) represented by the following formula:
Y = a x exp (0.06 X)
(Wherein Y represents the specific surface area [m 2 / m 3], X represents the number of cells [pieces / inch], and a represents the number of 100 or more and 1000 or less.

Description

FIELD OF THE INVENTION [0001] The present invention relates to an aluminum porous body, a heat transfer material,

The present invention relates to an aluminum porous body having a three-dimensional mesh-like structure, a heat transfer material and a heat exchange device.

A metal material having a high thermal conductivity is used as the heat transfer material used in the heat exchanger. Further, for the purpose of increasing the heat exchange efficiency and downsizing the device, studies have been made to increase the surface area by forming a large number of heat transfer materials in a thin plate or forming grooves in the heat transfer material.

For example, in Japanese Patent Application Laid-Open No. H07-190664 (Patent Document 1), it has been proposed to use a copper porous body or a copper alloy porous body for a heat transfer member. Specifically, a mixed powder of a metal such as nickel, aluminum, chromium, palladium, or silver, which is different from copper oxide powder or copper oxide powder, sinter as a metal in a reducing atmosphere, and a property of being integrated with a metal plate . Accordingly, Patent Document 1 discloses obtaining a heat transfer pipe or a heat transfer plate in which a metal porous body having a three-dimensional network structure is integrally attached to a metal plate or a metal pipe.

In addition, since electronic parts and the like using a semiconductor circuit generate heat by use, it is required to efficiently dissipate heat. For example, Japanese Unexamined Patent Application Publication No. 2012-124391 (Patent Document 2) discloses a heat transfer control member that performs heat transfer control between a heating element and its surrounding environment, and includes a heat transfer member having a porous metal layer having a three- A control member is proposed.

In the electrothermal control member described in Patent Document 2, the porous metal layer is made of a foamed metal having a three-dimensional mesh-like structure in which a plurality of pores formed by a continuous framework communicate with each other and has a porosity of 30% to 98% , And a thickness of 0.05 mm to 50 mm. This foamed metal is formed by foaming a foamable slurry containing a metal powder and a foaming agent into a sheet form and pores are opened to the top and side surfaces and the vicinity of the center in the thickness direction is densely And one of the front and back surfaces is formed more densely than the other surface.

In order to raise the heat exchange efficiency in the same volume of the heat transfer material using the metal porous body produced by the above-described sintering method, it is necessary to increase the specific surface area by decreasing the cell diameter of the porous metal body. However, if the cell pore size is reduced to increase the heat exchange efficiency, there is a problem that the pressure loss of the gas passing through the porous metal article becomes large.

Japanese Patent Application Laid-Open No. 07-190664 Japanese Laid-Open Patent Publication No. 2012-124391

In view of the above problems, it is an object of the present invention to provide an aluminum porous body which can be used as a heat transfer material having a very large specific surface area, an excellent heat exchange efficiency, and a small gas pressure loss.

DISCLOSURE OF THE INVENTION As a result of intensive investigations to solve the above problems, the present inventors have found that a conventional method of producing an aluminum porous body having a three-dimensional mesh structure by a plating method (for example, Japanese Laid-Open Patent Publication No. 2011-225950) The inventors have found that the specific surface area of the aluminum porous article can be made very large by further improving the composition, and thus the present invention has been accomplished. That is, the present invention has the following configuration.

(1) An aluminum porous body mainly composed of aluminum, wherein the aluminum porous body has an aluminum porous body having a three-dimensional mesh-like structure and having a specific surface area (Y) represented by the following formula:

Y = a x exp (0.06 X)

(Where Y represents the specific surface area [m 2 / m 3], X represents the number of cells [pieces / inch], a represents the number of 100 or more and 1000 or less, and Napier number e) is 2.72).

The aluminum porous article described in the above (1) has very fine irregularities on the entire surface of its skeletal surface, and has a very large specific surface area as compared with the conventional aluminum porous article. Since aluminum is a metal having a high thermal conductivity, the above-mentioned aluminum porous article is excellent in heat exchange efficiency and can be used as a heat transfer material having a small pressure loss of gas.

In the present invention, the main component of aluminum means that the content of aluminum in the aluminum porous article is 90% by mass or more.

(2) The aluminum porous body according to (1), wherein the framework of the aluminum porous body is hollow.

By manufacturing an aluminum porous article by the plating method, the skeleton of the aluminum porous article can be made hollow. Since the aluminum porous body having such a hollow skeleton can flow gas to the inside of the skeleton, it can be used as a heat transfer material having more excellent heat exchange efficiency.

(3) The aluminum porous body according to (1) or (2), wherein the purity of aluminum constituting the aluminum porous body is 99.7 mass% or more.

Since aluminum is a metal having a high thermal conductivity as described above, by increasing the purity of aluminum, an aluminum porous article having a higher thermal conductivity can be obtained.

(4) The aluminum porous body according to any one of (1) to (3), wherein the weight per volume of the aluminum porous body is 0.1 g / cm 3 or more and 1.0 g / cm 3 or less.

By setting the weight per volume of the aluminum porous body to 0.1 g / cm 3 or more, the skeleton of the aluminum porous body can be thickened, and the heat exchange efficiency is improved by increasing the specific surface area.

In addition, the thermal conductivity is improved by increasing the cross-sectional area of the skeleton. In addition, increasing the pressure loss by suppressing the weight per volume of the aluminum porous body to 1.0 g / cm 3 or less can be suppressed. In addition, the manufacturing cost of the aluminum porous article can be suppressed from becoming excessively high.

In the present invention, the weight per volume of the aluminum porous article refers to the mass per unit volume of the aluminum porous article.

(5) A heat conductive material comprising the aluminum porous body according to any one of (1) to (4).

The heat transfer material according to (5) is a heat transfer material having a very high specific surface area, excellent heat exchange efficiency, and excellent pressure loss of gas.

(6) A heat exchange apparatus using the aluminum porous article according to any one of (1) to (4).

The heat exchanger described in (6) above has an extremely high heat exchange efficiency because it uses the aluminum porous article of the present invention as a heat transfer material. Therefore, it is possible to reduce the size of the heat exchanger as compared with the conventional heat exchanger.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an aluminum porous article which can be used as a heat transfer material having a very large specific surface area, excellent heat exchange efficiency, and low pressure loss of gas.

1 is a view showing an equivalent circuit for evaluating capacitance.
2 is a diagram showing an outline of a measurement cell for measuring an AC impedance.

(Mode for carrying out the invention)

≪ Aluminum porous article &

The aluminum porous article according to the present invention is an aluminum porous article comprising aluminum as a main component. The aluminum porous article has an aluminum porous body having a three-dimensional mesh-like structure and a specific surface area (Y)

Y = a x exp (0.06 X)

(Wherein Y represents the specific surface area [m 2 / m 3], X represents the number of cells [pieces / inch], and a represents the number of 100 or more and 1000 or less.

As described above, the porous aluminum body according to the present invention has minute unevenness on the skeleton surface, and has a very large specific surface area. That is, the specific surface area can be made larger than that of the conventional aluminum porous article without making the cell pore smaller than necessary. Therefore, by using the aluminum porous article of the present invention as a heat transfer material, the heat exchange efficiency can be improved while maintaining the cell loss to some extent and keeping the pressure loss low.

In the above formula, X represents the number of cells (number / inch) of the aluminum porous article, and is preferably 6 to 60 pieces / inch. Since the number of cells of the aluminum porous article is 6 / inch or more, the specific surface area can be made sufficiently large, and the heat exchange efficiency can be increased. Further, when the number of cells of the porous aluminum body is 60 pieces / inch or less, excessive increase in pressure loss can be suppressed.

The number of cells of the aluminum porous body is more preferably 10 to 33 pieces / inch, and further preferably 10 to 20 pieces / inch.

In the present invention, the number of cells (X) of the aluminum porous body is defined as the number of cells per 1 inch (25.4 mm). The number of cells can be obtained by drawing a straight line of 1 inch on an enlarged image obtained by observing a horizontally sliced aluminum porous body with a microscope and counting the number of cells crossing the straight line. In this case, five places are counted and an average thereof is taken.

When a resin molded article such as foamed urethane is used as a starting material for producing an aluminum porous article, the number of cells of the aluminum porous article may be the same as the number of cells of the resin molded article.

The cell number of the foamed resin molded article can be obtained in the same manner as in the case of the above-mentioned aluminum porous article.

In the above formula, a represents a number of not less than 100 but not more than 1,000, more preferably not less than 200 and not more than 1,000, and still more preferably not less than 600 and not more than 1,000.

In the present invention, the specific surface area (Y) refers to a value measured by a capacitance method. This capacitance method is a measuring method that uses the fact that the capacitance of the metal material is proportional to the surface area as shown in the following theoretical expression.

(Theoretical formula)

C =? X (A / d)

C: capacitance,?: Permittivity, d: distance between two electrodes, A: surface area of sample

Specifically, first, a plurality of aluminum plates having the same purity as the sample and whose surface area is already known are prepared, and the respective electrostatic capacities are evaluated to prepare a calibration curve of "capacitance" versus "surface area". Then, by evaluating the capacitance of the sample, the surface area can be obtained by the calibration method.

The capacitance of the aluminum plate and the sample for preparing the calibration curve are evaluated by first measuring the AC impedance and analyzing the result using an equivalent circuit shown in Fig. As shown in FIG. 2, the AC impedance can be measured using a platinum electrode as a reference electrode in a NaCl solution having a concentration of 5% by mass. At this time, the measurement frequency is set to 100 kHz to 10 Hz to confirm that the influence of the dissolution reaction of aluminum is not remarkable. Then, data in the range of 10 kHz to 1 kHz is used for analysis.

The aluminum porous article of the present invention preferably has a hollow skeleton. As a result, gas can pass through both the inside and the outside of the skeleton, and a heat transfer material having excellent heat exchange efficiency can be obtained. An aluminum porous body having such a skeleton as a hollow can be obtained by a plating method in which aluminum is electrolytically plated on the surface of a resin molding having a three-dimensional mesh-like structure.

Further, in the aluminum porous article of the present invention, the purity of aluminum constituting the aluminum porous article is preferably 99.7 mass% or more. This makes it possible to use the aluminum porous body as a heat transfer material having a higher thermal conductivity. In order to make the purity of aluminum 99.7 mass% or more, the purity of aluminum used as the anode in the above-described plating method may be 99.7 mass% or more. In this method, the purity of aluminum constituting the porous aluminum body can be increased to 99.9 mass% or more, and further, it can be made to be 99.99 mass% or more.

When electroplating is performed, the surface of the resin molded body having a three-dimensional mesh-like structure may be coated with carbon powder, or may be subjected to a conductive treatment by Sn, Ni plating or the like. , And the like.

The aluminum porous body according to the present invention preferably has a weight per volume of 0.1 g / cm3 or more and 1.0 g / cm3 or less. By setting the weight per volume of the aluminum porous article to 0.1 g / cm 3 or more and 1.0 g / cm 3 or less, it can be used as a heat transfer material having a very large specific surface area and excellent heat exchange efficiency. The weight per volume of the aluminum porous article is more preferably 0.1 g / cm 3 or more and 0.6 g / cm 3 or less, and still more preferably 0.1 g / cm 3 or more and 0.4 g / cm 3 or less.

In order to obtain such an aluminum porous article with a weight per volume, the amount of the aluminum film to be formed on the surface of the resin molded article having the three-dimensional mesh-like structure may be suitably adjusted in the plating method described above.

≪ Production method of aluminum porous article >

As described above, the aluminum porous body according to the present invention can be produced by a plating method using a molten salt bath. More specifically, a resin molding having a three-dimensional mesh-like structure (hereinafter, simply referred to as " resin molding ") having a communication hole such as foamed urethane is used as a core material, After that, electrolytic plating of aluminum is performed in a molten salt bath. Thereafter, the resin structure on which the aluminum film is formed is subjected to heat treatment to eliminate the resin, whereby an aluminum porous body in which only the metal layer remains can be obtained.

Hereinafter, a method for producing an aluminum porous article according to the present invention will be described in more detail.

(Preparation of a resin molded article having a three-dimensional mesh structure)

First, a resin molding having a three-dimensional mesh-like structure and having a communication hole is prepared. As the material of the resin molded article, any resin can be selected. Polyurethane, melamine, polypropylene, polyethylene, and the like.

The foamed urethane and the foamed melamine can be preferably used as a foamed resin molded article because they have a high porosity and are also excellent in thermal decomposition property as well as having pore communication. Foamed urethane is preferable in that it is uniform in pore size, is easy to obtain, and is also small in pore diameter.

In many cases, the resin molded product has residues such as a foaming agent and unreacted monomer in the production process of the foam, and therefore, it is preferable for the subsequent process to carry out the cleaning process. The resin molded body constitutes a mesh three-dimensionally as a framework, thereby forming a continuous pore as a whole. The skeleton of the foamed urethane is substantially triangular in cross section perpendicular to the extending direction.

The foamed resin molded article preferably has a porosity of 80% to 98% and a pore size of 420 to 4230 탆.

The porosity is defined by the following formula.

Porosity = (1- (weight of porous material [g] / (volume of porous material [cm 3] x material density)) x 100 [%]

The pore size is obtained by enlarging the surface of the resin molded article with a microscope or the like and counting the number of pores per 1 inch (25.4 mm) as the number of cells to obtain an average pore size with an average pore size = 25.4 mm / cell number.

(Conductivity on the surface of the resin molded article)

In order to electrolytically coat aluminum on the surface of the resin molded article, the surface of the resin molded article is subjected to a conductive treatment in advance. The conductive treatment is not particularly limited as long as it is a treatment capable of forming a layer having conductivity on the surface of the resin molded article. For example, electroless plating of a conductive metal such as nickel, vapor deposition of aluminum or the like, and application of a conductive paint containing conductive particles such as sputtering or carbon can be selected.

As an example of the conductive treatment, a method of conducting the conductive treatment by the sputtering treatment of aluminum and a method of conducting the conductive treatment of the surface of the resin molded product by using carbon as the conductive particle will be described below.

- sputtering of aluminum -

The sputtering treatment using aluminum is not limited to a target of aluminum, and may be carried out according to a conventional method. For example, a DC voltage is applied between a holder and a target (aluminum) while an inert gas is introduced after attaching a resin molding to a substrate holder. Thereby, an ionized inert gas is caused to collide with aluminum, and aluminum particles repelled by force are deposited on the surface of the resin molding to form a sputter film of aluminum. The sputtering treatment is preferably carried out at a temperature at which the resin molded article is not dissolved. Specifically, the sputtering treatment may be performed at about 100 to 200 캜, preferably about 120 to 180 캜.

- Carbon dispensing -

First, a carbon paint as a conductive paint is prepared. The suspension as the conductive paint preferably includes carbon particles, a binder, a dispersant, and a dispersion medium. In order to uniformly apply the conductive particles, it is necessary that the suspension maintains a uniform suspended state. Therefore, it is preferable that the suspension is maintained at 20 캜 to 40 캜. The reason for this is that when the temperature of the suspension becomes less than 20 캜, the uniform suspension state collapses and only the dentifrice concentrates on the surface of the skeleton constituting the network structure of the resin molded article to form a layer. In this case, the layer of coated carbon particles is easily peeled off, and it is difficult to form a metal plating firmly adhered to each other. On the other hand, when the temperature of the suspension exceeds 40 캜, the evaporation amount of the dispersing agent is large and the suspension is concentrated with the lapse of the coating treatment time, and the amount of the carbon to be coated is likely to fluctuate. The particle diameter of the carbon particles is preferably 0.01 to 5 占 퐉, more preferably 0.01 to 2 占 퐉. If the particle diameter is large, the cells of the resin molded body are filled or the smooth plating is inhibited. If the particle diameter is too small, it becomes difficult to secure sufficient conductivity.

The application of the carbon particles to the resin molded article can be carried out by dipping the resin molded article to be subjected to the suspension, followed by squeezing and drying.

(Formation of aluminum film on the surface of resin molded article)

As a method of forming the aluminum film on the surface of the resin molded article, a plating method using a molten salt bath is adopted.

- molten salt plating -

Electrolytic plating is performed in a molten salt to form an aluminum film on the surface of the resin molded article.

Plating of aluminum in the molten salt bath makes it possible to uniformly form a thick aluminum film on the surface of a complex skeleton structure such as a resin molding having a three-dimensional mesh structure. A direct current is applied in the molten salt with the resin molded body whose surface is electrically conductive as the negative electrode and aluminum as the positive electrode.

As the molten salt, an organic molten salt which is a process salt of an organic halide and an aluminum halide, and an inorganic molten salt which is a process salt of an alkali metal halide and an aluminum halide can be used. When an organic molten salt bath that melts at a relatively low temperature is used, electrolytic plating can be performed without decomposing the resin molded body as a base. As the organic halide, imidazolium salt, pyridinium salt and the like can be used. Specifically, 1-ethyl-3-methylimidazolium chloride (EMIC) and butylpyridinium chloride (BPC) are preferable.

Since the molten salt is deteriorated when water or oxygen is mixed in the molten salt, it is preferable that the plating is performed under an atmosphere of an inert gas such as nitrogen or argon and also in a closed environment.

As the molten salt bath, a molten salt bath containing nitrogen is preferable, and an imidazolium salt bath is particularly preferably used. In the case of using a salt which melts at a high temperature as a molten salt, the resin is more likely to dissolve or decompose in the molten salt than the growth of the plated film, and a plating film can not be formed on the surface of the resin molded article. The imidazolium salt bath can be used without affecting the resin even at a relatively low temperature. As the imidazolium salt, a salt containing an imidazolium cation having an alkyl group at 1,3-position is preferably used, and in particular, aluminum chloride-1-ethyl-3-methylimidazolium chloride (AlCl ₃ -EMIC) The salt is most preferably used because it is highly stable and difficult to decompose. In this molten salt bath, plating with foamed urethane resin or melted melamine resin is possible, and the temperature of the molten salt bath is from 10 캜 to 100 캜, preferably from 25 캜 to 45 캜. The lower the temperature of the molten salt bath becomes, the narrower the current density range that can be plated, and the plating on the entire surface of the resin molded article becomes difficult. There is a problem that the shape of the resin molding to be a base material is liable to be damaged at a high temperature at which the temperature of the molten salt bath exceeds 100 캜. Through the above steps, an aluminum-resin structure having a resin molding as a core of the framework is obtained.

(Removal of resin)

The aluminum-resin structure thus obtained is subjected to a heat treatment in which the aluminum-resin structure is heated to 500 ° C or higher in a nitrogen atmosphere or in the air, for example, to dissolve the resin to obtain an aluminum porous body. It has been found that, in order to produce the aluminum porous article of the present invention, it is effective to add an improvement to this process which has been performed conventionally. Specifically, the following methods can be used

- Treatment of plating liquid adhered to resin structure -

Since the plating solution adheres to the surface of the resin molded article having the aluminum film on the surface thus obtained, the water washing treatment is performed, and then the heating treatment is performed.

At this time, by performing the water washing treatment without sufficiently removing the plating liquid, an aluminum porous article having fine irregularities formed on the skeletal surface can be obtained. This is considered to be because heat is generated by the reaction of the plating liquid containing the molten salt with water, and aluminum reacts with water on the surface of the aluminum film to form boehmite. In general, the boehmite undergoes dehydration reaction at 450 DEG C or higher to be transformed into gamma -alumina having micropores. However, in the present invention, since the resin is exposed to a high temperature of 500 DEG C or more when the resin is removed from the resin structure by combustion, As the resultant boehmite is transformed into? -Alumina, fine irregularities are formed on the skeleton surface.

In order to obtain an aluminum porous body having fine irregularities formed on the skeleton surface by such a method, it is preferable to perform the water washing treatment in a state in which the amount of the plating liquid adhered to the resin structural body is 20 mL / m 2 to 2000 mL / m 2. More preferably, the deposition amount of the plating liquid is 200 mL / m 2 to 2000 mL / m 2, and more preferably 1000 mL / m 2 to 2000 mL / m 2.

- Water cleaning treatment of resin structure -

In the treatment of the plating solution adhered to the resin structure, even when the plating solution is sufficiently removed, an aluminum porous article having minute irregularities formed on the skeleton surface can be produced as follows. That is, as described above, the water washing treatment is performed in order to remove the plating liquid adhered to the resin molding having the aluminum film on the surface, but at this time, the water attached to the resin structure is not sufficiently removed, . In this case also, in the step of heating the resin structure, aluminum reacts with water on the surface of the aluminum film at around 80 ° C to cause boehmite, and after that, the boehmite is further heated so that gamma -alumina .

In order to obtain an aluminum porous body having fine irregularities formed on the skeleton surface by such a method, it is preferable to carry out the combustion removal treatment of the resin with the water amount adhered to the resin structural body being 10 mL / m 2 to 1000 mL / m 2. More preferably, the water adhesion amount is from 100 mL / m 2 to 1000 mL / m 2, and more preferably from 500 mL / m 2 to 1000 mL / m 2.

- combustion removal of resin from resin structure -

In addition to the above two methods, it is also possible to produce an aluminum porous body having microscopic unevenness on the skeleton surface. That is, even when the water of the plating liquid is sufficiently drained and the water adhered by the subsequent water rinsing treatment is sufficiently removed, the subsequent step of removing the resin may be performed in an atmosphere containing a large amount of water and a high dew point. For this purpose, for example, heat treatment may be performed by heating at 500 ° C or higher while humidified air is being supplied. Even in this case, it is considered that the boehmite transforms into gamma -alumina having micropores by reacting the water supplied in the atmosphere in which the heat treatment is performed and aluminum at about 80 DEG C to generate boehmite and then further heating.

In order to obtain an aluminum porous body having fine irregularities formed on the skeleton surface by such a method, it is preferable to set the dew point temperature of the atmosphere in the resin combustion removing step to 0 to 60 캜. More preferably, the dew point temperature is 20 占 폚 to 60 占 폚, and more preferably 40 占 폚 to 60 占 폚.

<Heat Transfer Materials and Heat Exchanger>

By using the aluminum porous article of the present invention as a heat transfer material, it is possible to obtain a heat transfer material having a very large specific surface area, excellent heat exchange efficiency, and less gas pressure loss. In addition, since the heat exchange device using the aluminum porous article of the present invention as a heat transfer material has a very high heat exchange efficiency, it can be made smaller than a conventional heat exchange device.

The heat exchanger is not particularly limited, but includes means for thermally connecting the aluminum porous body of the present invention to a heat generating body or a cooling body as a heat transfer material, and transferring the heat transferred to the heat transfer material to another medium by a blowing means or the like It is good if it is one.

As an example of the heat exchanger, those used as a heat radiation material of a semiconductor device can be cited. For example, it can be used in place of a conventional so-called heat sink or the like. That is, the aluminum porous body of the present invention is provided on the heat generating element, and air is attracted by a fan or the like, so that it is possible to cool efficiently.

As another example of the heat exchanger, an air conditioner and the like can be mentioned. In this case, the aluminum porous body of the present invention may be used in place of the fins provided on the surface of the heat transfer tube through which the refrigerant or the heat passes. By sending air to the porous aluminum body, the heat transferred from the heat transfer pipe can be transferred to the air.

The means for providing the aluminum porous body on the surface of the heat transfer tube is not particularly limited, and for example, it can be bonded by using a solder or a flux containing aluminum alloy powder or the like. At this time, the thickness of the aluminum porous body used as the heat transfer material is not particularly limited, and may be suitably changed according to the design of the heat exchange apparatus. An aluminum porous body having an arbitrary thickness can be obtained by appropriately changing the thickness of the resin molded body used as the starting material in the above-described production by the plating method.

It is also possible to provide the aluminum porous body of the present invention not only on the outer surface but also on the inner surface of the heat transfer tube. As a result, the heat from the refrigerant (or the heat) flowing through the heat transfer pipe can be efficiently transferred to the outside.

Example

Hereinafter, the present invention will be described in more detail on the basis of examples, but these examples are merely examples, and the production apparatus and the like of the aluminum porous article of the present invention are not limited thereto. The scope of the present invention is indicated by the scope of the claims, and includes all changes within the meaning and range of equivalents of the claims.

[Example 1]

(Formation of conductive layer)

As the resin molded article, a urethane foam having a porosity of 97%, a number of cells of 10 pieces / inch, a pore size of about 2540 탆 and a thickness of 10 mm was prepared and cut into an 80 mm × 50 mm square. On the surface of the polyurethane foam, aluminum was deposited by sputtering to a weight of 10 g / m 2 to form a conductive layer.

(Molten salt plating)

The urethane foam having a conductive layer formed on its surface was set as a work in a jig having a power feed function and then placed in a glove box made of low water content (dew point -30 占 폚 or lower) while being kept in an argon atmosphere. Of a molten salt aluminum plating bath (33 mol% EMIC-67 mol% AlCl ₃ to which 0.5 g / L 1,10-phenanthroline was added). The jig having the work set was connected to the cathode side of the rectifier, and an aluminum plate (purity 99.99 mass%) of the counter electrode was connected to the anode side.

A direct current having a current density of 6 A / dm 2 was applied for 60 minutes to obtain a structure in which an aluminum film having a mass of 0.15 g / cm 3 was formed on the surface of the urethane foam. Stirring was carried out using a rotor made of Teflon (registered trademark). The current density is a value calculated by the area of the outer surface of the urethane foam.

(Removal of resin)

The structure thus obtained was taken out of the plating bath and subjected to a water rinsing treatment with the plating liquid adhering amount of 1500 mL / m 2. After the water rinsing treatment, the structure was dried well and the heat treatment was carried out at 600 占 폚 for 30 minutes in an atmosphere of a dew point temperature of -15 占 폚 in a state where the water adhesion amount was 6 ml / m2. As a result, the resin disappeared, and the aluminum porous article 1 (purity 99.99 mass%) of the present invention was obtained.

-evaluation-

<Specific surface area>

The specific surface area of the obtained aluminum porous article 1 was measured by the aforementioned capacitance method. Specifically, a plurality of aluminum plates having a purity of 99.99% by mass and whose surface area was already known were prepared, and their capacitances were evaluated to prepare a calibration curve of "capacitance" versus "surface area". Then, the surface area was determined by the calibration method by evaluating the electrostatic capacity of the aluminum porous body.

The results are shown in Table 1.

<Microscopic observation>

Observation of the obtained porous aluminum body 1 by an electron microscope revealed that a number of minute irregularities were formed on the surface.

[Example 2]

In the manufacturing method of the aluminum porous body according to Example 1, the water washing treatment was carried out with the plating liquid adhering amount of 10 mL / m 2, and then the dew point temperature was -10 ° C , The aluminum porous body 2 was obtained in the same manner as in Example 1. The results are shown in Table 1 below.

The evaluation results are shown in Table 1. &lt; tb &gt; &lt; TABLE &gt;

[Example 3]

In the method for producing an aluminum porous body according to Example 1, a water washing treatment was performed in a state where the plating liquid adhered amount was 6 mL / m &lt; 2 &gt; Except that the heat treatment was carried out under the same conditions as in Example 1, to obtain an aluminum porous body 3.

The evaluation results are shown in Table 1. &lt; tb &gt; &lt; TABLE &gt;

[Example 4]

An aluminum porous article 4 was obtained in the same manner as in Example 1 except that a urethane foam having 30 cells / inch was used in the production method of the aluminum porous article according to Example 1.

The evaluation results are shown in Table 1. &lt; tb &gt; &lt; TABLE &gt;

[Example 5]

An aluminum porous body 5 was obtained in the same manner as in Example 2 except that a urethane foam having a cell number of 30 pieces / inch was used in the manufacturing method of the aluminum porous body according to Example 2.

The evaluation results are shown in Table 1. &lt; tb &gt; &lt; TABLE &gt;

[Example 6]

An aluminum porous article 6 was obtained in the same manner as in Example 3 except that a urethane foam having 30 cells / inch was used in the method for producing an aluminum porous article according to Example 3.

The evaluation results are shown in Table 1. &lt; tb &gt; &lt; TABLE &gt;

[Comparative Example 1]

In the method for producing an aluminum porous body according to Example 1, a water washing treatment was performed in a state where the plating liquid adhered amount was 10 mL / m &lt; 2 &gt;, and then the dew point temperature was -10 DEG C The aluminum porous body 7 was obtained in the same manner as in Example 1, except that the heat treatment was performed under an atmosphere of nitrogen.

The evaluation results are shown in Table 1. &lt; tb &gt; &lt; TABLE &gt;

[Comparative Example 2]

In the method for producing an aluminum porous body according to Example 4, a water washing treatment was performed in a state where the plating liquid adhered amount was 10 mL / m &lt; 2 &gt;, and then the dew point temperature was -10 The aluminum porous article 8 was obtained in the same manner as in Example 4 except that the heat treatment was conducted in an atmosphere of &lt; RTI ID = 0.0 &gt;

The evaluation results are shown in Table 1. &lt; tb &gt; &lt; TABLE &gt;

[Comparative Example 3]

Duocel (registered trademark): material A6061 manufactured by ERG Co., which was produced by a casting method, was prepared as an aluminum porous article 9.

The evaluation results are shown in Table 1. &lt; tb &gt; &lt; TABLE &gt;

Claims (6)

As an aluminum porous body comprising aluminum as a main component,
The aluminum porous body has a three-dimensional mesh-like structure and further has an aluminum porous body having a specific surface area (Y) represented by the following formula:
Y = a x exp (0.06 X)
(Wherein Y represents the specific surface area [m 2 / m 3], X represents the number of cells [pieces / inch], and a represents the number of 100 or more and 1000 or less. The method according to claim 1,
Wherein the aluminum porous body has a hollow skeleton. 3. The method according to claim 1 or 2,
Wherein the purity of aluminum constituting the aluminum porous article is 99.7 mass% or more. 4. The method according to any one of claims 1 to 3,
Wherein the weight per volume of the aluminum porous body is 0.1 g / cm3 or more and 1.0 g / cm3 or less. A heat transfer material comprising the aluminum porous body according to any one of claims 1 to 4. A heat exchange apparatus using the aluminum porous body according to any one of claims 1 to 4.

Images