JP6148141B2 - Porous metal body and method for producing porous metal body - Google Patents

Description

  The present invention relates to a metal porous body, a current collector, an electrochemical device, and a method for producing the metal porous body that are excellent in heat resistance and strength.

  A metal porous body produced by subjecting a resin porous body having a three-dimensional network structure to metal plating is used in various fields such as various filters, catalyst carriers, and battery electrodes. For example, Celmet (registered trademark, manufactured by Sumitomo Electric Industries, Ltd.), which is a metal porous body made of nickel, 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.

  Moreover, the corrosion resistance mechanical strength and heat resistance can be improved by alloying nickel forming the skeleton of the porous metal body with chromium. As such a metal porous body, for example, Japanese Patent Application Laid-Open No. 2010-171154 (Patent Document 1) discloses a current collector for a capacitor in which a nickel porous body alloyed with chromium includes a non-aqueous electrolyte containing a lithium salt. It is described that it can be used as a body.

JP 2010-171154 A

  As described above, a porous metal body made of a nickel-chromium alloy has excellent characteristics, but in the manufacturing process, it is necessary to perform a heat treatment in which the porous body is left in an inert atmosphere at 1100 ° C. for about one week. However, there are problems in that the manufacturing cost is high and it is not suitable for industrial continuous production.

  Therefore, the present invention provides a metal porous body that is low in manufacturing cost, can be manufactured by a method suitable for continuous production, and has excellent heat resistance and mechanical strength to the same extent as a metal porous body made of a nickel-chromium alloy. For the purpose. Another object of the present invention is to provide a method for producing the metal porous body.

The present invention adopts the following configuration in order to solve the above problems.
(1) That is, the present invention is a porous metal body having a three-dimensional network structure containing nickel, tin, and iron, wherein the tin content is 1% by mass or more and 25% by mass or less, It is a metal porous body whose iron content is 5 mass% or more and 25 mass% or less.

  According to the present invention, a metal porous body having excellent heat resistance and mechanical strength as much as a metal porous body made of a nickel-chromium alloy can be provided by a manufacturing method suitable for continuous production at low cost.

3 is a graph showing an SS curve obtained by a compressive load test of a metal porous body 8. 3 is a graph showing an SS curve obtained by a compressive load test of a metal porous body 9. It is a graph showing SS curve obtained by the compressive load test of the nickel-chromium porous body. It is a graph showing the SS curve obtained by the compressive load test of the nickel-tin porous body. 3 is a diagram illustrating an X-ray diffraction spectrum of a metal porous body 8. FIG. 3 is a diagram illustrating an X-ray diffraction spectrum of a metal porous body 9. FIG. 3 is a diagram illustrating an X-ray diffraction spectrum of a metal porous body 5. FIG. 3 is a photograph showing the result of observing the skeleton surface of a porous metal body 8 with an SEM. It is a photograph which shows the presence position of a tin component in the same visual field as FIG. 3A. It is a photograph which shows the presence position of an iron component in the same visual field as FIG. 3A.

First, the contents of the embodiment of the present invention will be listed and described.
(1) A porous metal body according to an embodiment of the present invention is a porous metal body having a three-dimensional network structure including nickel (Ni), tin (Sn), and iron (Fe), and the inclusion of the tin A porous metal body having an amount of 1% by mass or more and 25% by mass or less and an iron content of 5% by mass or more and 25% by mass or less.
Hereinafter, the “metal porous body having a three-dimensional network structure” is also simply referred to as “metal porous body”.

The metal porous body described in the above (1) is a metal porous body excellent in heat resistance and mechanical strength. For this reason, it can be preferably used as a filter medium for a filter used by standing in a high temperature environment, or as a current collector for electrochemical devices such as batteries and capacitors. Further, as will be described later, the manufacturing cost is low, and it can be obtained by a method suitable for continuous production.
The metal porous body of the present invention has a tin content of 1% by mass to 25% by mass, an iron content of 5% by mass to 25% by mass, and the remaining metal component is nickel. Although it is preferable, other metal components may be included as inevitable impurities. Moreover, you may contain other components intentionally in the range which does not impair the effect of the metal porous body of this invention that is excellent in heat resistance and mechanical strength.

(2) The metal porous body according to the embodiment of the present invention, Ni ₃ Sn content is 1 mass% or more and 30 mass% or less.
As a result of various studies by the present inventors, in the case of a metal porous body made of an alloy of nickel and tin, the strength of the metal porous body is increased and hard when Ni ₃ Sn is formed as an intermetallic compound. However, it has been found that brittleness is suppressed when an iron component is contained in the skeleton. That is, it is possible to increase the mechanical strength by forming Ni ₃ Sn in the skeleton of the metal porous body, and to further prevent the skeleton from becoming brittle by containing the iron component.

(3) A method for producing a porous metal body according to an embodiment of the present invention includes a step of conducting a conductive treatment on the surface of a resin molded body having a three-dimensional network structure, and a nickel plating layer and tin plating on the resin molded body. And a step of forming a resin structure by forming an iron plating layer and a step of diffusing nickel, tin and iron by heat-treating the resin structure.
The method for producing a porous metal body described in (3) above can be produced continuously because all metal components can be formed by electrolytic plating, and is a production method excellent in mass productivity. Moreover, the formation order of the plating layer of each metal formed on the surface of the resin molding is not limited, and the nickel plating layer, the tin plating layer, and the iron plating layer may be formed in any order. However, since the metal porous body has a higher nickel content than the tin and iron contents, it is preferable to form the nickel plating layer first in consideration of handling of the substrate after plating.

(4) A method for producing a porous metal body according to an embodiment of the present invention includes a step of conducting a surface treatment of a resin molded body having a three-dimensional network structure, a nickel plating layer, and tin on the resin molded body And a process for forming a resin structure by forming an alloy plating layer of iron and iron, and a step of diffusing nickel, tin and iron by heat-treating the resin structure. .
Since the method for producing a porous metal body according to the above (4) includes a step of forming an alloy plating layer of tin and iron on the surface of the nickel plating layer, the plating step can be reduced, and the cost can be reduced. A metal porous body can be provided. Further, the order of formation of the metal plating layer formed on the surface of the resin molded body is not limited, and either the nickel plating layer or the alloy plating layer of tin and iron may be formed first.

(5) A method for producing a porous metal body according to an embodiment of the present invention includes a step of conducting a conductive treatment on a surface of a resin molded body having a three-dimensional network structure with a conductive treatment material containing tin, and the resin molded body. And a step of forming a resin structure by forming a nickel plating layer and an iron plating layer, and a step of diffusing nickel, tin and iron by heat-treating the resin structure. Is the method.
The method for producing a porous metal body according to the above (5) uses a conductive treatment material containing tin when the surface of the resin molded body is subjected to a conductive treatment, and therefore a step of forming a tin plating layer is unnecessary thereafter. Become. For this reason, a metal porous body can be provided at a lower cost. Further, the order of forming the metal plating layers formed on the surface of the resin molded body is not limited, and either the nickel plating layer or the iron plating layer may be formed first. However, since the metal porous body has a higher nickel content than the iron content, it is preferable to form the nickel plating layer first in consideration of handling of the substrate after plating.

(6) A method for producing a metal porous body according to an embodiment of the present invention includes a step of conducting a conductive treatment on a surface of a resin molded body having a three-dimensional network structure with a conductive treatment material containing tin, and the resin molded body. Forming a nickel-iron alloy plating layer on the surface of the substrate, and heat-treating the resin structure on which the nickel-iron alloy plating layer is formed to diffuse nickel, tin, and iron. It is a manufacturing method of a metal porous body.
In the method for producing a porous metal body described in (6) above, since a conductive treatment material containing tin is used when conducting the conductive treatment on the surface of the resin molded body, a subsequent step of forming a tin plating layer is unnecessary. is there. Furthermore, since the process of forming the alloy plating layer of nickel and iron is included, the plating process can be performed only once. For this reason, a metal porous body can be provided at lower cost than the manufacturing method as described in said (4) and (5).

  Moreover, the metal porous body which concerns on embodiment of this invention can further be obtained by the manufacturing method as described in the following (i)-(iv).

(I) a step of conducting the conductive treatment of the surface of the resin molded body having a three-dimensional network structure with a conductive treatment material containing iron;
Forming a resin structure by forming a nickel plating layer and a tin plating layer on the resin molded body; and
Heat treating the resin structure to diffuse nickel, tin and iron;
The manufacturing method of the metal porous body containing this.

  The method for producing a porous metal body described in (i) above uses a conductive treatment material containing iron when conducting a conductive treatment on the surface of the resin molded body, and therefore there is no need to subsequently form an iron plating layer. Become. For this reason, a metal porous body can be provided at a lower cost. Further, the order of forming the metal plating layers formed on the surface of the resin molded body is not limited, and either the nickel plating layer or the tin plating layer may be formed first. However, since the metal porous body has a higher nickel content than the tin content, it is preferable to form the nickel plating layer first in consideration of handling of the substrate after plating.

(Ii) a step of conducting a conductive treatment on the surface of the resin molded body having a three-dimensional network structure with a conductive treatment material containing tin and iron;
Forming a nickel plating layer on the surface of the resin molded body to form a resin structure;
Heat treating the resin structure to diffuse nickel, tin and iron;
The manufacturing method of the metal porous body containing this.

  The method for producing a porous metal body described in (ii) above uses a conductive treatment material containing tin and iron when conducting a conductive treatment on the surface of the resin molded body. A forming step is not necessary. For this reason, since it is only necessary to form a nickel plating layer on the surface of the resin molded body, only one plating step is required, and a porous metal body can be provided at low cost.

(Iii) a step of conducting a conductive treatment by sputtering tin on the surface of a resin molded body having a three-dimensional network structure;
Forming a resin structure by forming a nickel plating layer and an iron plating layer on the resin molded body; and
Heat treating the resin structure to diffuse nickel, tin and iron;
The manufacturing method of the metal porous body containing this.

  In the method for producing a metal porous body described in (iii) above, since the resin molded body is subjected to a conductive treatment by sputtering tin on the surface of the resin molded body, a subsequent step of forming a tin plating layer becomes unnecessary. . For this reason, a metal porous body can be provided at a lower cost. Further, the order of forming the metal plating layers formed on the surface of the resin molded body is not limited, and either the nickel plating layer or the iron plating layer may be formed first. However, since the metal porous body has a higher nickel content than the iron content, it is preferable to form the nickel plating layer first in consideration of handling of the substrate after plating.

(Iv) conducting the conductive treatment by sputtering iron on the surface of the resin molded body having a three-dimensional network structure;
Forming a resin structure by forming a nickel plating layer and a tin plating layer on the resin molded body; and
Heat treating the resin structure to diffuse nickel, tin and iron;
The manufacturing method of the metal porous body containing this.

  In the method for producing a metal porous body described in (iv) above, since the resin molded body is subjected to a conductive treatment by sputtering iron on the surface of the resin molded body, a subsequent step of forming an iron plating layer becomes unnecessary. . For this reason, a metal porous body can be provided at a lower cost. Further, the order of forming the metal plating layers formed on the surface of the resin molded body is not limited, and either the nickel plating layer or the tin plating layer may be formed first. However, since the metal porous body has a higher nickel content than the tin content, it is preferable to form the nickel plating layer first in consideration of handling of the substrate after plating.

[Details of the embodiment of the present invention]
The specific example of the metal porous body which concerns on embodiment of this invention is demonstrated below. In addition, this invention is not limited to these illustrations, is shown by description of a claim, and it is intended that all the changes within the meaning and range equivalent to a claim are included. .

<Metal porous body>
The porous metal body according to the embodiment of the present invention is a porous metal body having a three-dimensional network structure and includes nickel, tin, and iron. In order to make the skeleton structure of a porous metal body into a three-dimensional network structure, for example, the metal layer is formed by forming each metal layer on the surface of a porous resin body having a three-dimensional network structure as in the above-described manufacturing method. What is necessary is just to manufacture a porous.

Since the metal porous body contains tin, heat resistance and mechanical strength are improved as compared with the nickel porous body. In particular, when Ni ₃ Sn which is an intermetallic compound is formed in the manufacturing process of the metal porous body, an effect that the metal porous body becomes hard is obtained. Further, when a large amount of Ni ₃ Sn is formed, the metal porous body tends to become hard but brittle, but the metal porous body according to the embodiment of the present invention changes the metal structure due to containing iron. Brittleness can be suppressed. Therefore, the metal porous body according to the embodiment of the present invention has an effect of being hard and resistant to compression and tension.

The content of tin in the metal porous body is 1% by mass or more and 25% by mass or less. If the tin content is less than 1% by mass, the effect of improving the heat resistance of the metal porous body cannot be obtained sufficiently. On the other hand, if the tin content exceeds 25% by mass, the amount of Ni ₃ Sn formed in the metal porous body manufacturing process becomes too large, and the effect of suppressing embrittlement by iron cannot be obtained sufficiently. End up.
From the above viewpoint, the tin content in the metal porous body is more preferably 3% by mass or more and 20% by mass or less, and further preferably 4% by mass or more and 18% by mass or less.

The iron content in the porous metal body is 5% by mass or more and 25% by mass or less. If the iron content is less than 5% by mass, the effect of suppressing embrittlement by Ni ₃ Sn cannot be obtained sufficiently. Moreover, when iron content exceeds 25 mass%, heat resistance will fall.
From the above viewpoint, the iron content in the metal porous body is more preferably 7% by mass or more and 22% by mass or less, and further preferably 9% by mass or more and 20% by mass or less.

In the porous metal body according to the embodiment of the present invention, the content of Ni ₃ Sn in the skeleton is preferably 1% by mass or more and 30% by mass or less. When the content of Ni ₃ Sn is 1% by mass or more, the metal porous body can be sufficiently hardened. Further, when the content of Ni ₃ Sn is 30% by mass or less, it is possible to suppress the metal porous body from becoming too brittle and causing the skeleton to collapse. From such a viewpoint, the content of Ni ₃ Sn in the metal porous body is more preferably 3% by mass or more and 25% by mass or less, and further preferably 5% by mass or more and 20% by mass or less.
In addition, the content (mass%) of Ni ₃ Sn in the metal porous body can be quantified by, for example, a ratio of peak heights measured by X-ray diffraction (XRD).

In the metal porous body according to the embodiment of the present invention, the remaining metal component other than tin and iron is preferably nickel as described above, but inevitably contains impurities, or the metal of the present invention. In the range which does not impair the effect of a porous body, you may contain other metal components intentionally.
In the case of intentionally containing other metal components, for example, tungsten (W) may be contained for the purpose of improving heat resistance and mechanical strength.

<Usage example of porous metal>
The metal porous body according to the embodiment of the present invention can be used for various applications, for example, current collectors and electrodes for electrochemical devices, catalyst carriers, filters, heat exchangers, and the like. It is done.

<Method for producing porous metal body>
The porous metal body according to the embodiment of the present invention can be manufactured by various methods. Examples of the manufacturing method include the methods described in (3) to (6) and (i) to (iv). Can be mentioned.
Below, the said manufacturing method is demonstrated in detail.

(Resin molding having a three-dimensional network structure)
The resin molded body having a three-dimensional network structure may be any known or commercially available resin, and a resin foam, nonwoven fabric, felt, woven fabric, or the like can be used. Moreover, these can also be used in combination as needed. Although it does not specifically limit as a raw material, The thing which can be removed by incineration after plating a metal is preferable. In addition, in handling the resin molded body, a sheet-like material is preferably a flexible material because it breaks when the rigidity is high.

  It is preferable to use a resin foam as the resin molding. Examples of the resin foam include urethane foam, foamed styrene, and foamed melamine resin. Among these, urethane foam is particularly preferable from the viewpoint of high porosity.

The porosity of the resin molded body is not limited and is usually about 60% to 97%, preferably about 80% to 96%. The thickness of the resin molded body is not limited and is appropriately determined according to the intended use of the metal porous body to be obtained. Usually, it is about 300 μm or more and 5000 μm or less, preferably 400 μm or more and 2000 μm or less.
Below, the case where a foamed resin is used as a resin molded body having a three-dimensional network structure will be described as an example.

(Conductive treatment)
The conductive treatment is not particularly limited as long as a conductive layer can be provided on the surface of the resin molded body. Examples of the material constituting the conductive layer (conductive coating layer) include carbon powder in addition to metals such as nickel, copper, tin, iron, tungsten, titanium, and stainless steel.
As a specific example of the conductive treatment, for example, when a metal such as nickel, tin, or iron is used, electroless plating treatment, gas phase treatment such as sputtering, vapor deposition / ion plating, and the like are preferably exemplified. Moreover, when using materials, such as alloy metals, such as stainless steel, and graphite, the process of apply | coating the mixture obtained by adding a binder to the fine powder of these materials to the surface of a resin molding is mentioned preferably.

  The electroless plating treatment using nickel can be performed, for example, by immersing the foamed resin in a known electroless nickel plating bath such as a nickel sulfate aqueous solution containing sodium hypophosphite as a reducing agent. If necessary, the resin molded body may be immersed in an activation liquid containing a trace amount of palladium ions (cleaning liquid manufactured by Kanigen Co., Ltd.) or the like before immersion in the plating bath.

  As a sputtering process using nickel, tin or iron, for example, first, a resin molded body is attached to a substrate holder, and then a direct current is applied between the holder and a target (nickel, tin or iron) while introducing an inert gas. Apply voltage. Thus, the ionized inert gas is allowed to collide with nickel, tin, or iron, and the blown-off nickel particles, tin particles, or iron particles may be deposited on the surface of the resin molded body.

  When applying conductive paint such as carbon powder, the surface of the resin molded body is conductive powder (for example, powder of metal material such as stainless steel, crystalline graphite, amorphous carbon black, etc. And a method of applying a mixture of carbon powder) and a binder. At this time, tin powder and carbon powder may be used, or iron powder and carbon powder may be used. In this case, the amount of tin powder or iron powder is such that the tin content in the metal porous body is 1% by mass or more and 15% by mass or less, and the iron content is 5% by mass or more and 25% by mass or less. Then, the subsequent tin plating process or iron plating process becomes unnecessary.

The basis weight (attachment amount) of the conductive coating layer is a final metal composition that is combined with the basis weight of nickel plating, tin plating or iron plating in the subsequent step, and the tin content is 1% by mass or more and 15% by mass. Hereinafter, the iron content may be adjusted to be 5% by mass or more and 25% by mass or less.
When nickel is used for the conductive coating layer, it may be formed continuously on the surface of the resin molded body, and the basis weight is not limited, but is usually about 5 g / m ² or more and 15 g / m ² or less, preferably 7 g / m ^2. m ² or more, it may be set to the degree 10 g / m ² or less.

(Electrolytic nickel plating process)
What is necessary is just to perform an electrolytic nickel plating process in accordance with a conventional method. As the plating bath used for the electrolytic nickel plating treatment, a known or commercially available bath can be used, and examples thereof include a watt bath, a chloride bath, a sulfamic acid bath, and the like.
The resin structure having a conductive layer formed on the surface by electroless plating or sputtering is immersed in a plating bath, and the resin structure is connected to the cathode and the nickel counter electrode is connected to the anode, and direct current or pulsed intermittent current is applied. Thus, a nickel coating can be further formed on the conductive layer.
What is necessary is just to adjust the basis weight of an electrolytic nickel plating layer so that content of tin may be 1 to 15 mass% as a final metal composition of a metal porous body.

(Tin plating process)
The step of forming the tin plating layer on the resin structure can be performed, for example, as follows. That is, as a sulfuric acid bath, a plating bath having a composition of stannous sulfate 55 g / L, sulfuric acid 100 g / L, cresol sulfonic acid 100 g / L, gelatin 2 g / L, β naphthol 1 g / L is prepared, and the cathode current density is set. By setting the anode current density to ^{2 A} / dm ² , the anode current density to 1 A / dm ² or less, the temperature to 20 ° C., and stirring (cathode oscillation) to 2 m / min, the tin plating layer can be formed.
The basis weight of tin plating may be adjusted so that the final metal composition of the metal porous body has a tin content of 1% by mass or more and 15% by mass or less.

In order to improve the adhesion of tin plating, it is desirable to perform strike nickel plating immediately before to remove the surface oxide film of the metal porous body and put it into the tin plating solution without getting dried. Thereby, the adhesiveness of a plating layer can be improved.
The conditions for strike nickel plating can be as follows, for example. That is, by preparing a wood strike nickel bath having a composition of nickel chloride 240 g / L, hydrochloric acid (having a specific gravity of about 1.18) 125 ml / L, setting the temperature to room temperature, and using nickel or carbon for the anode It can be carried out.

The above plating procedure is summarized as follows: degreasing with an A-screen (cathodic electrolytic degreasing 5 A / dm ² × 1 minute), hot water washing, water washing, acid activity (hydrochloric acid immersion 1 minute), wood strike nickel plating treatment (5 to 10 A / dm ² × 1 min), processed to tin plating, washed and dried without washing and drying.

(Iron plating process)
The step of forming the tin plating layer on the resin structure can be performed, for example, as follows. That is, as a plating bath, for example, FeCl ₂ .4H ₂ O is 2.00 mol / L, CaCl ₂ is 1.5 mol / L, saccharin is 10 mmol / L, and CH ₃ (CH ₂ ) ₆ CH ₂ OSO ₃ Na is used. An electroiron plating solution of 0.30 mmol / L can be used. In this example, saccharin is added as a stress relaxation agent, and sodium lauryl sulfate is added as a hydrogen gas defoaming agent. The pH of the plating solution may be adjusted to 2 and the bath temperature may be about 50 ° C.
The basis weight of the iron plating may be adjusted so that the final metal composition of the metal porous body has an iron content of 5% by mass or more and 25% by mass or less.

(Alloy plating process of tin and iron)
The step of forming the tin-iron alloy plating layer on the resin structure can be performed, for example, as follows. That is, as a plating bath, for example, a tin-iron alloy plating solution of 0.1 mol / L of SnSO ₄ , 0.05 mol / L of FeSO ₄ , 0.3 mol / L of sodium gluconate, and 1 g / L of polyethylene glycol is used. be able to. The pH may be adjusted to 4 and the bath temperature may be about 30 ° C.
The basis weight of the alloy plating of tin and iron is, as the final metal composition of the metal porous body, the tin content is 1% by mass or more and 25% by mass or less, and the iron content is 5% by mass or more. What is necessary is just to adjust so that it may become 25 mass% or less.

(Nickel and iron alloy plating process)
The step of forming the alloy plating layer of nickel and iron on the resin structure can be performed, for example, as follows. That is, as a plating bath, for example, nickel chloride (II) 170 mmol / L, nickel sulfate (II) 80 mmol / L, iron (II) sulfate 11 mmol / L, boric acid 404 mmol / L, ammonium chloride 187 mmol / L, saccharin 5 A nickel iron electroplating solution of .5 mmol / L can be used. The pH may be adjusted to 2.5 and the bath temperature may be about 30 ° C.
The basis weight of the alloy plating of nickel and iron is, as a final metal composition of the metal porous body, the tin content is 1% by mass or more and 25% by mass or less, and the iron content is 5% by mass or more. What is necessary is just to adjust so that it may be 25 mass% or less and the remainder will be nickel.

(Plating solution circulation during plating)
In general, it is difficult to uniformly plate a substrate such as a resin molded body having a three-dimensional network structure. It is preferable to circulate the plating solution in order to prevent non-attachment to the inside or to reduce the difference in the amount of plating adhesion between the inside and the outside. As a circulation method, there are methods such as using a pump and installing a fan inside the plating tank. Also, if a plating solution is sprayed onto the resin molded body using these methods, or if the resin molded body is placed adjacent to the suction port, the plating solution can easily flow inside the resin molded body, which is effective.

(Removal of molded resin)
The method of removing the resin molded body used as the base material from the resin structure having the metal plating layer formed on the surface is not limited, and examples thereof include a chemical treatment and a combustion removal method by incineration. In the case of incineration, for example, the heating may be performed in an oxidizing atmosphere such as air of about 600 ° C. or higher.
The metal porous body containing nickel, tin, and iron is obtained by heat-treating the obtained metal porous body in a reducing atmosphere to reduce the metal.

(Heat treatment)
Since the majority of the skeleton surface of the metal porous body may be formed of nickel as it is after metal plating, it is necessary to diffuse the tin component and the iron component by heat treatment. Tin and iron can be diffused in an inert atmosphere (reduced pressure, nitrogen, argon, etc.) or in a reducing atmosphere (hydrogen).
In this heat treatment step, the tin component and the iron component are sufficiently diffused in the nickel plating layer, and the concentration ratio of the front side and the inner side tin or iron of the porous metal skeleton is 2/1 or more. It is preferable to be within a range of / 2. The concentration ratio is more preferably 3/2 or more and 2/3 or less, still more preferably 4/3 or more and 3/4 or less, and most preferably it is uniformly diffused.

  If the heat treatment temperature is too low, it takes time for diffusion, and if it is too high, the heat treatment temperature may soften and damage the porous structure due to its own weight. The heat treatment temperature is more preferably 500 ° C. or higher and 1150 ° C. or lower, and still more preferably 700 ° C. or higher and 1100 ° C. or lower.

(Metal weight)
The total amount of the metal basis weight after forming the conductive coating layer, the nickel plating layer, the tin plating layer, and the iron plating layer may be appropriately changed according to the use of the metal porous body. For example, 200 g / m ² As described above, it is preferably 2000 g / m ² or less. More preferably, they are 300 g / m < ² > or more and 1200 g / m < ² > or less, More preferably, they are 400 g / m < ² > or more and 1000 g / m < ² > or less. By setting the total amount of metal basis weight to 200 g / m ² or more, the strength of the metal porous body can be made sufficient. Moreover, the raise of manufacturing cost can be suppressed by making the total amount of metal fabric weights into 2000 g / m < ² > or less.

(Pore diameter)
The average pore diameter of the metal porous body may be appropriately changed according to the use of the metal porous body, but it is preferably, for example, 150 μm or more and 1000 μm or less. More preferably, they are 300 micrometers or more and 700 micrometers or less, More preferably, they are 350 micrometers or more and 600 micrometers or less. In addition, when using as an electrical power collector, 150 micrometers or more and 1000 micrometers or less are preferable. More preferably, they are 200 micrometers or more and 700 micrometers or less, More preferably, they are 300 micrometers or more and 600 micrometers or less.
The average pore diameter is a value obtained from the reciprocal of the number of cells of the metal porous body. The number of cells is a numerical value obtained by counting the number of cells on the outermost surface crossing the line when a line having a length of 1 inch is drawn on the surface of the metal porous body, and the unit is the number of cells / inch. However, 1 inch shall be 2.54 cm.

(Confirmation of metal porous body composition)
Quantitative measurement using inductively coupled plasma (ICP) can be performed to determine the mass% of the contained element.

(Diffusion confirmation of tin and iron)
To confirm the diffusion state of tin and iron by conducting energy dispersive X-ray spectroscopy (EDX) measurement from a cross section of a porous metal body and comparing the spectrum of the skeleton front side and the skeleton inside Can do.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, these Examples are illustrations, Comprising: The metal porous body of this invention etc. are not limited to these. The scope of the present invention is defined by the scope of the claims, and includes meanings equivalent to the scope of the claims and all modifications within the scope.

<Manufacture of metal porous body>
[Metal porous body 1]
(Conductive treatment of resin moldings with a three-dimensional network structure)
As a resin molded body having a three-dimensional network structure, a 2.0 mm-thick polyurethane sheet (27 to 33 cells / inch, average cell diameter of 900 μm, gas efficiency of 94 vol%) was used. In order to make the surface of this polyurethane sheet conductive, a conductive paint in which 100 g of carbon black, which is amorphous carbon having a particle size of 0.01 to 0.2 μm, is dispersed in 0.5 L of a 10% aqueous acrylate resin solution. Was made. Then, the polyurethane sheet was continuously immersed in the paint, squeezed with a roll, and then dried, so that the polyurethane sheeter was subjected to a conductive treatment. As a result, a conductive coating layer was formed on the surface of the polyurethane sheet (a sheet-like resin molded body having a three-dimensional network structure).

(Nickel plating)
The polyurethane sheet whose surface was made conductive as described above was subjected to nickel plating with a basis weight of 374 g / m ² to form a nickel plating layer. As the plating solution, a nickel sulfamate plating solution was used. The sulfamic acid bath was an aqueous solution having a concentration of 450 g / L nickel sulfamate and 30 g / L boric acid, and the pH was adjusted to 4. Nickel plating was performed at a temperature of 55 ° C. and a current density of 20 ASD (A / dm ² ). Thereby, a resin structure containing nickel was obtained.

(Tin plating)
A tin plating layer having a basis weight of 162 g / m ² was applied to the surface of the resin structure containing nickel prepared above to form a tin plating layer. As a tin plating solution, a composition having a composition of 55 g / L of stannous sulfate, 100 g / L of sulfuric acid, 100 g / L of cresolsulfonic acid, 2 g / L of gelatin, and 1 g / L of β-naphthol with respect to 1000 g of water was used. The bath temperature of the plating bath was 20 ° C., and the anode current density was 1 A / dm ² . The plating solution was stirred so as to be 2 m / min by the cathode swing.

(Iron plating)
The surface of the resin structure containing nickel and tin produced as described above was subjected to iron plating with a basis weight of 169 g / m ² to form an iron plating layer. As the iron plating solution, FeCl ₂ .4H ₂ O is 2.00 mol / L, CaCl ₂ is 1.5 mol / L, saccharin is 10 mmol / L, CH ₃ (CH ₂ ) ₆ CH ₂ OSO ₃ Na is 0.30 mmol. An / L electric iron plating solution was used. Saccharin was added as a stress relaxation agent, and sodium lauryl sulfate was added as a hydrogen gas defoaming agent. The pH of the plating solution was adjusted to 2, and the bath temperature was 50 ° C.
The anode current density was 1 A / dm ² . The plating solution was stirred so as to be 2 m / min by the cathode swing.

(Removal of molded resin and diffusion of metal)
The base material (polyurethane sheet) was burned and removed by heating the resin structure containing nickel, tin and iron at 1000 ° C. for 15 minutes in the atmosphere. At this time, since the metal porous body is also partially oxidized, reduction treatment was further performed in a reducing (hydrogen) atmosphere at 1000 ° C. for 20 minutes.
In the EDX spectrum comparison, there is no difference between the front side and the inner side, and it is considered that tin and iron are evenly diffused.

[Metal porous body 2] to [Metal porous body 21]
In the production of [Metal porous body 1], the same as [Metal porous body 1] except that the basis weight of nickel plating, the basis weight of tin plating, and the basis weight of iron plating were as shown in Table 1 below. [Metal porous body 2] to [Metal porous body 21] were manufactured. The basis weight of each plating was adjusted to be about 700 g / m ² after Sn and Fe plating having a desired composition ratio was applied.
[Metal porous body 1] to [metal porous body 13] are examples, and [metal porous body 14] to [metal porous body 21] are comparative examples.

[Metal porous body 22]
(Nickel plating)
The polyurethane sheet was subjected to a conductive treatment in the same manner as in the method for producing [Metal porous body 1], and then the surface was subjected to nickel plating with a basis weight of 370 g / m ² . Nickel plating was performed in the same manner as in [Metal porous body 1].
(Alloy plating of tin and iron)
On the surface of the resin structure containing nickel prepared above, 178 g / m ² is basis weight of tin, as the basis weight of the iron is 164 g / m ^2, was subjected to alloy plating of tin and iron. As the plating solution, a tin-iron alloy plating solution of SnSO ₄ of 0.1 mol / L, FeSO ₄ of 0.05 mol / L, sodium gluconate 0.3 mol / L, and polyethylene glycol 1 g / L was used. The pH was adjusted to 4, the bath temperature was 30 ° C., and the current density was 1 A / dm ² . Further, the plating solution was stirred so as to be 2 m / min by the cathode swing.
(Removal of molded resin and diffusion of metal)
About the resin structure containing nickel, tin, and iron obtained above, combustion removal of the base material and metal reduction treatment were performed in the same manner as in the method for producing [Metal porous body 1].
The obtained metal porous body has no difference between the front side and the inner side in the EDX spectrum comparison, and it is considered that tin and iron are evenly diffused.

[Metal porous body 23]
In the production of the above [Metal porous body 22], the same as [Metal porous body 22] except that the basis weight of nickel plating, the basis weight of tin plating, and the basis weight of iron plating were as shown in Table 1 below. Thus, [metal porous body 23] was produced.

[Metal porous body 24]
(Conductive treatment of resin moldings with a three-dimensional network structure)
The polyurethane sheet used in the production of [Metal porous body 1] was subjected to a conductive treatment in the same manner as [Metal porous body 1] except that a conductive coating containing tin powder was used. The content of tin powder in the conductive paint was 6% by mass. The basis weight of tin on the surface of the polyurethane sheet was 171 g / m ² .
(Nickel plating)
The polyurethane sheet whose surface was made conductive as described above was subjected to nickel plating with a basis weight of 364 g / m ² to form a nickel plating layer. Nickel plating was performed under the same conditions as in the method for producing [Metal porous body 1]. However, the current density was adjusted to 1 A / dm ^2, and the plating solution was stirred so as to be 2 m / min due to the cathode swing.
(Iron plating)
The surface of the resin structure containing tin and nickel produced as described above was subjected to iron plating at a weight of 178 g / m ² to form an iron plating layer. Iron plating was performed under the same conditions as in the method for producing [Metal porous body 1].
(Removal of molded resin and diffusion of metal)
About the resin structure containing nickel, tin, and iron obtained above, combustion removal of the base material and metal reduction treatment were performed in the same manner as in the method for producing [Metal porous body 1].
The obtained metal porous body has no difference between the front side and the inner side in the EDX spectrum comparison, and it is considered that tin and iron are evenly diffused.

[Metal porous body 25]
In the production of the above [metal porous body 24], the same as [metal porous body 24] except that the basis weight of nickel plating, the basis weight of tin plating, and the basis weight of iron plating were as shown in Table 1 below. Thus, [metal porous body 25] was produced.

[Metal porous body 26]
(Conductive treatment of resin moldings with a three-dimensional network structure)
In the same manner as the preparation of [metal porous body 24 'is the basis weight of tin polyurethane sheet surface is conductive treatment a polyurethane sheet as a 175 g / m ^2.
(Alloy plating of nickel and iron)
An alloy plating of nickel and iron was formed on the polyurethane sheet having a conductive surface as described above so that the basis weight of nickel was 358 g / m ² and the basis weight of iron was 168 g / m ² . Nickel plating was performed to form a nickel plating layer. As a plating solution, nickel chloride (II) 170 mmol / L, nickel sulfate (II) 80 mmol / L, iron (II) sulfate 11 mmol / L, boric acid 404 mmol / L, ammonium chloride 187 mmol / L, saccharin 5.5 mmol / L The nickel iron electroplating solution was used. The pH of the plating solution was adjusted to 2.5, the bath temperature was 30 ° C., and the current density was 1 A / dm ² . Further, the plating solution was stirred so as to be 2 m / min by the cathode swing.
(Removal of molded resin and diffusion of metal)
About the resin structure containing nickel, tin, and iron obtained above, combustion removal of the base material and metal reduction treatment were performed in the same manner as in the method for producing [Metal porous body 1].
The obtained metal porous body has no difference between the front side and the inner side in the EDX spectrum comparison, and it is considered that tin and iron are evenly diffused.

[Metal porous body 27]
In the production of the above [metal porous body 26], the same procedure as in [metal porous body 26] was performed except that the basis weight of nickel plating, the basis weight of tin plating, and the basis weight of iron plating were as shown in Table 1 below. Thus, [Metal porous body 27] was produced.
[Metal porous body 22] to [Metal porous body 27] are examples.

<Evaluation of metal porous body>
(Compressive load test)
The [metal porous body 1] to [metal porous body 27] were each cut into a size of 20 mm × 20 mm to form a test piece, and a compression load test was performed in which a change amount when a load was applied was measured. And based on the result, SS curve (Stress-Strain Curve, stress-strain curve) was created, and the inflection point load was examined. The results are shown in Table 2.

Further, for [Metal porous body 8] and [Metal porous body 9], two test pieces were prepared as described above, and SS curves obtained by the compression load test are shown in FIGS. 1A and 1B. In the graphs of FIGS. 1A and 1B, the vertical axis represents the applied pressure (N) applied to the porous metal body, and the horizontal axis represents the displacement (mm) of the porous metal body.
For reference, an SS curve obtained by preparing a test piece of a nickel-chromium porous body (Cr 40 mass%) obtained by the method described in JP 2010-171154 A and performing a compression load test is shown in FIG. 1C. In addition, an SS curve obtained by producing a nickel-tin porous body containing no iron and having a tin content of 10% by mass, 15% by mass, and 17% by mass and performing a compression load test using the test piece is shown. Shown in FIG. 1D.
From these results, it is shown that the metal porous body according to the embodiment of the present invention is much stronger than the nickel-tin porous body and has the same strength as the nickel-chromium porous body. It was done. Further, the strength of the metal porous body with a higher iron content was improved.

(Weight increase after heating test)
Each of the [metal porous body 1] to [metal porous body 27] was cut into a size of 50 mm × 50 mm to obtain a test piece, and the weight was measured. And these test pieces were left still in 750 degreeC air | atmosphere for 1 hour.
Then, each test piece was taken out and weighed, and the weight change due to metal oxidation was measured. The results are shown in Table 2.

[Metal porous body 1] to [Metal porous body 13] and [Metal porous body 22] to [Metal porous body 27] had a change in weight and a small amount of oxidation although the surface color changed to black after heat treatment. Moreover, it was shown that the amount of oxidation is so small that a metal porous body with much tin content.
The nickel porous body of [Metal porous body 14] changed to green after the heat treatment, the weight change was large, and the oxidation amount was large.

(Measurement by X-ray diffraction method)
With respect to [Metal porous body 5], [Metal porous body 8] and [Metal porous body 9], the diffraction X-ray intensity of these metal porous bodies is measured by X-ray diffraction method, and each of them is measured by RIR (Reference Intensity Ratios) method. The contents of NiFe and Ni ₃ Sn in the metal porous body were quantified.
As a result, the content of [metal porous body 8] in a state where Ni, Sn, and Fe were in solid solution was 96% by mass, and the content of Ni ₃ Sn was 4% by mass. [Metal porous body 9] is 99 wt% content of Ni-Sn-Fe solid solution, the content of Ni ₃ Sn was 1 mass%. Further, [the metal porous body 5] is 93 wt% content of Ni-Sn-Fe solid solution, the content of Ni ₃ Sn was 7 mass%.
2A shows the X-ray diffraction spectrum of [Metal porous body 8], FIG. 2B shows the X-ray diffraction spectrum of [Metal porous body 9], and FIG. 2C shows the X-ray diffraction spectrum of [Metal porous body 5]. 2A to 2C, the horizontal axis represents the diffraction angle 2θ (deg), and the vertical axis represents the intensity (cps).

(Observation with a scanning electron microscope)
The result of observing the skeleton surface of [metal porous body 8] with a scanning electron microscope (SEM) is shown in FIG. 3A. Moreover, the result of having confirmed the presence position of a tin component by EDX in the same visual field as FIG. 3A is shown to FIG. 3B. Further, FIG. 3C shows the result of confirming the existence position of the iron component by EDX in the same field of view as FIG. 3A.
As a result, it was shown that tin and iron were uniformly diffused in the skeleton of the porous metal body.

Claims (6)

A porous metal body having a three-dimensional network structure including nickel, tin, and iron,
The tin content is 1% by mass or more and 25% by mass or less,
The metal porous body whose content of the said iron is 5 mass% or more and 25 mass% or less. The metal porous body according to claim 1, wherein the content of Ni ₃ Sn is 1% by mass or more and 30% by mass or less. A step of conducting a conductive treatment on the surface of the resin molded body having a three-dimensional network structure;
Forming a resin structure by forming a nickel plating layer, a tin plating layer, and an iron plating layer on the resin molded body; and
Heat treating the resin structure to diffuse nickel, tin and iron;
The manufacturing method of the metal porous body containing this. A step of conducting a conductive treatment on the surface of the resin molded body having a three-dimensional network structure;
Forming a nickel plating layer and an alloy plating layer of tin and iron on the resin molded body to form a resin structure;
Heat treating the resin structure to diffuse nickel, tin and iron;
The manufacturing method of the metal porous body containing this. A step of conducting the surface of the resin molded body having a three-dimensional network structure with a conductive treatment material containing tin; and
Forming a nickel plated layer and an iron plated layer on the resin molded body to form a resin structure; and
Heat treating the resin structure to diffuse nickel, tin and iron;
The manufacturing method of the metal porous body containing this. A step of conducting the surface of the resin molded body having a three-dimensional network structure with a conductive treatment material containing tin; and
Forming a resin structure by forming an alloy plating layer of nickel and iron on the surface of the resin molded body;
Heat treating the resin structure to diffuse nickel, tin and iron;
The manufacturing method of the metal porous body containing this.