Porous metal

Abstract

This metallic porous body comprises: metallic skeletons; and partition walls which are integrally formed with the metallic skeletons and which are formed from the same material as that of the metallic skeletons. The metallic porous body has thereinside a plurality of cells of a polyhedral shape. The edges of the polyhedral shapes are formed from the metallic skeletons. This metallic porous body has thereinside portions where openings of the cells demarcated by the edges are occluded by the partition walls.

Description

【Technical Field】 【0001】 The present disclosure relates to a metal porous body. This application claims priority based on Japanese Patent Application No. 2022-048338, filed on March 24, 2022. All the descriptions described in the Japanese patent application are incorporated herein by reference. 【Background Art】 【0002】 For example, International Publication No. 2019 / 244480 (Patent Document 1) describes a metal porous body. The metal porous body described in Patent Document 1 has a three-dimensional network structure metal skeleton. The metal skeleton is hollow. Inside the metal porous body described in Patent Document 1, there are a plurality of communicating pores defined by the metal skeleton. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 International Publication No. 2019 / 244480 【Summary of the Invention】 【0004】 The metal porous body of the present disclosure includes a metal skeleton and partition walls formed of the same material as the metal skeleton integrally with the metal skeleton. Inside the metal porous body, there are a plurality of cells having a polyhedral shape. The sides of the polyhedral shape are constituted by the metal skeleton. Inside the metal porous body, there are portions where the openings of the cells defined by the sides are blocked by the partition walls. 【Brief Description of the Drawings】 【0005】 [Figure 1] FIG. 1 is a perspective view of the metal porous body 10. [Figure 2] FIG. 2 is a schematic cross-sectional view showing the internal structure of the metal porous body 10. [Figure 3] FIG. 3 is a schematic cross-sectional view taken along III-III in FIG. 2. [Figure 4] Figure 4 is a schematic perspective view of cell 14. [Figure 5] Figure 5 is a process diagram showing the manufacturing method of the porous metal body 10. [Figure 6] Figure 6 is a schematic cross-sectional view of the resin molded body 20. [Figure 7] Figure 7 is a process diagram showing a method for manufacturing a porous metal body 10 according to Modification 1. [Figure 8] Figure 8 is a process diagram showing a method for manufacturing a porous metal body 10 according to modified example 2. [Figure 9] Figure 9 is a graph showing the relationship between the number of charge / discharge cycles and discharge capacity for samples 1 to 3. [Modes for carrying out the invention] 【0006】 [Issues this disclosure aims to address] The porous metal described in Patent Document 1 may have insufficient rigidity because the pores inside are interconnected. This disclosure has been made in view of these problems of the prior art. More specifically, this disclosure provides a porous metal in which rigidity can be improved. 【0007】 [Effects of this disclosure] The porous metal material of this disclosure can improve the rigidity of the porous metal material. 【0008】 [Description of Embodiments in this Disclosure] First, embodiments of this disclosure will be listed and described. 【0009】 (1) The porous metal body according to the embodiment comprises a metal skeleton and partition walls formed integrally with the metal skeleton and made of the same material as the metal skeleton. Inside the porous metal body there are a plurality of polyhedral cells. The edges of the polyhedral shape are made of the metal skeleton. Inside the porous metal body there are places where the openings of cells defined by the edges are closed by partition walls. According to the porous metal body of (1) above, the rigidity of the porous metal body can be improved. 【0010】 (2) In the porous metal body described in (1) above, the metal layer constituting the metal skeleton may be made of a metal material with a Vickers hardness of less than 600 Hv. According to the porous metal body described in (2) above, even if the metal skeleton is made of a soft metal material, the rigidity of the porous metal body can be ensured. 【0011】 (3) In the porous metal body described in (1) above, the metal layer constituting the metal skeleton may be formed of a metal material with a Vickers hardness of 350 Hv or less. According to the porous metal body described in (3) above, even if the metal skeleton is formed of a soft metal material, the rigidity of the porous metal body can be ensured. 【0012】 (4) In the porous metal body described in (1) above, the metal layer constituting the metal skeleton may be made of a metal material with a Vickers hardness of 100 Hv or less. According to the porous metal body described in (3) above, even if the metal skeleton is made of a soft metal material, the rigidity of the porous metal body can be ensured. 【0013】 (5) In the porous metal body described in (2) above, the thickness of the metal layer may be 0.3 μm or more and 10 μm or less. 【0014】 (6) In the porous metal bodies described in (1) to (5) above, the metal skeleton may be made of tin, and the tin content may be 99.99 mass percent or more. The porous metal body described in (5) above can be used in a variety of applications, such as filters requiring heat resistance, oil mist collectors, batteries, electrolytic electrodes, fuel cell electrodes, catalyst carriers, electromagnetic shields, sound-absorbing materials, humidifying substrates, and shock-absorbing materials. 【0015】 (7) In the porous metal bodies described in (1) to (6) above, the metal layers constituting the metal framework may consist of layers of calcined tin particles. The porous metal body described in (4) above can be used in a variety of applications requiring heat resistance, such as filters, oil mist collectors, batteries, electrolytic electrodes, fuel cell electrodes, catalyst carriers, electromagnetic shields, sound-absorbing materials, humidifying substrates, and shock-absorbing materials. 【0016】 [Details of Embodiments of the Present Disclosure] Next, the details of the embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions will not be repeated. The metal porous body according to the embodiment is referred to as the metal porous body 10. 【0017】 (Configuration of Metal Porous Body 10) The configuration of the metal porous body 10 will be described below. 【0018】 FIG. 1 is a perspective view of the metal porous body 10. As shown in FIG. 1, the metal porous body 10 is, for example, in a sheet shape. Let the thickness of the metal porous body 10 be the thickness T1. The thickness T1 is, for example, 0.1 mm or more and 3 mm or less. 【0019】 FIG. 2 is a schematic cross-sectional view showing the internal structure of the metal porous body 10. FIG. 3 is a schematic cross-sectional view taken along III-III in FIG. 2. As shown in FIGS. 2 and 3, the metal porous body 10 has a metal skeleton 11. 【0020】 The metal skeleton 11 has, for example, a three-dimensional network structure. The metal skeleton 11 is integrally and continuously formed. The metal skeleton 11 has a metal layer 12 and a hollow portion 13. The metal layer 12 is on the surface of the metal skeleton 11. The hollow portion 13 is inside the metal skeleton 11. That is, the metal skeleton 11 is hollow inside. In a cross-sectional view perpendicular to the extending direction thereof, the metal skeleton 11 is, for example, substantially triangular in shape. 【0021】 The metal layer 12 is formed of a metallic material. For example, the metal layer 12 is formed of a metallic material with a Vickers hardness of 600 Hv or less. Preferably, the metal layer 12 is formed of a metallic material with a Vickers hardness of 350 Hv or less, and more preferably of a metallic material with a Vickers hardness of 100 Hv or less. The metal layer 12 may also be formed of a metallic material with a Vickers hardness of 50 Hv or less. The Vickers hardness of the metal layer 12 is measured according to the Vickers hardness test method specified in JIS Z 2244. Specific examples of metallic materials with a Vickers hardness of 600 Hv or less include tin (Sn), indium (In), nickel (Ni), silver (Ag), gold (Au), copper (Cu), etc. 【0022】 The Vickers hardness of nickel formed by matte electroplating is in the range of 100 Hv to 250 Hv, and the Vickers hardness of nickel formed by bright electroplating is in the range of 300 Hv to 350 Hv. The Vickers hardness of nickel-cobalt alloys formed by plating is in the range of 300 Hv to 600 Hv. The Vickers hardness of tin or tin alloys formed by plating is in the range of 3 Hv to 60 Hv. The Vickers hardness of indium or indium alloys formed by plating is lower than that of tin or tin alloys formed by plating. The Vickers hardness of copper, silver, and gold formed by plating is in the ranges of 40 Hv to 85 Hv, 55 Hv to 90 Hv, and 20 Hv to 80 Hv, respectively. 【0023】 When the metal layer 12 is formed of tin, the metal layer 12 preferably has a tin content of 99.9 mass percent or more. When the metal layer 12 is formed of tin, the metal layer 12 more preferably has a tin content of 99.99 mass percent or more. In these cases, the remainder of the metal layer 12 other than tin is carbon (C), nitrogen (N), sodium (Na), lead (Pb), bismuth (Bi), antimony (Sb), copper, iron (Fe), arsenic (As), zinc (Zn), etc. 【0024】 The tin content in the metal layer 12 is measured by the following method. First, the porous metal 10 is dissolved in a solution. This solution is, for example, a 1 mol / L hydrochloric acid solution with 1 percent nitric acid added. Second, the mass of tin in the solution is measured by inductively coupled plasma (ICP) analysis of the above solution. The tin content in the metal layer 12 is obtained by dividing the mass of tin in this solution by the mass of the porous metal 10 dissolved in this solution. 【0025】 If the metal layer 12 is made of tin, the metal layer 12 may have a first layer 12a and a second layer 12b. The first layer 12a is the layer on the side of the hollow portion 13. The second layer 12b is the layer on the surface side of the metal framework 11 (i.e., the side of the pores 15, which will be described later). The first layer 12a is a sputtered layer formed by, for example, sputtering. The second layer 12b is an electroplated layer formed by, for example, electroplating. The metal layer 12 may consist of an electroplated layer. 【0026】 The metal layer 12 may consist of layers of multiple fired tin particles. Within the metal layer 12, the multiple tin particles are necked together. The first layer 12a may be a layer of multiple fired tin particles, and the second layer 12b may be an electrolytic tin plating layer formed by electrolytic plating. 【0027】 The thickness of the metal layer 12 is denoted as thickness T2. Preferably, thickness T2 is between 0.3 μm and 100 μm. In measuring thickness T2, firstly, a scanning electron microscope (SEM) is used to obtain a cross-sectional image of the metal framework 11 perpendicular to its extension direction. Secondly, the thickness of the metal layer 12 is measured based on this cross-sectional image. At this time, the thickness of the metal layer 12 is measured at the point where it is at its minimum value. This measured value becomes thickness T2. 【0028】 The porous metal body 10 is composed of multiple cells 14. Figure 4 is a schematic perspective view of a cell 14. Only one cell 14 is shown in Figure 4. As shown in Figure 4, the cell 14 has a polyhedral structure, and the parts corresponding to each edge of the polyhedral structure are the metal skeleton 11. The polyhedral structure of the cell 14 is, for example, a dodecahedron structure. However, the polyhedral structure of the cell 14 is not limited to this. The polyhedral structure of the cell 14 may be a cubic structure, an icosahedron structure, or the like. 【0029】 Inside each cell 14, there are pores 15 defined by the metal framework 11. As described above, since the porous metal body 10 is composed of multiple cells 14, there are multiple pores 15 inside the porous metal body 10. 【0030】 Cell 14 has multiple holes 16. The holes 16 are surrounded by a metal skeleton 11. The holes 16 communicate with pores 15. Therefore, the pores 15 of two adjacent cells 14 are connected pores. However, in at least some of the multiple cells 14, there may be areas where at least some of the multiple holes 16 are blocked by partition walls 17 (see hatched areas in Figure 4). That is, partition walls 17 are placed between two adjacent pores 15, and at least some of the multiple pores 15 inside the porous metal body 10 may not be connected pores. To put this in other words, inside the porous metal body 10, there are areas where the openings of cells 14, which are defined by the edges of a polyhedron, are blocked by partition walls 17. 【0031】 The partition wall 17 is made of the same material as the metal framework 11 and is integrally formed with the metal framework 11. Furthermore, the partition wall 17 has the same structure as the metal framework 11. That is, the partition wall 17 is hollow inside and has a metal layer on its surface. 【0032】 The porosity of the porous metal 10 is, for example, 50 percent or more. The porosity of the porous metal 10 is calculated by {1-A / (B×C)}×100, where A is the weight of the porous metal 10, B is the apparent volume of the porous metal 10, and C is the true density of the porous metal 10. 【0033】 The average diameter of the pores 15 is, for example, between 200 μm and 1000 μm. In measuring the average diameter of the pores 15, firstly, a cross-sectional image of the porous metal body 10 is obtained using an electron microscope. Secondly, the number of cells 14 per inch (25.4 mm) is counted in the above cross-sectional image. Then, the value obtained by dividing 25.4 mm by the number of counted cells 14 is the average diameter of the pores 15. 【0034】 (Method for manufacturing a porous metal body 10) The manufacturing method for the porous metal body 10 is described below. 【0035】 Figure 5 is a process diagram showing the manufacturing method of the porous metal body 10. As shown in Figure 5, the manufacturing method of the porous metal body 10 includes a preparation step S1, a conductive treatment step S2, a plating step S3, and a resin molded body removal step S4. The conductive treatment step S2 is performed after the preparation step S1. The plating step S3 is performed after the conductive treatment step S2. The resin molded body removal step S4 is performed after the plating step S3. 【0036】 In preparation step S1, a resin molded body 20 is prepared. The resin molded body 20 is a foamed resin. The resin molded body 20 is formed from, for example, urethane. Figure 6 is a schematic cross-sectional view of the resin molded body 20. As shown in Figure 6, the resin molded body 20 has a skeleton 21. The skeleton 21 has a three-dimensional network structure. The skeleton 21 is solid. Multiple pores 22 exist inside the resin molded body 20. The pores 22 are demarcated by the skeleton 21. The resin molded body 20 has not undergone any defilming treatment (for example, removing the partition between two adjacent pores 22 by performing an explosion treatment). Therefore, some of the multiple pores 22 are interconnected, but some of the multiple pores 22 are not interconnected. The porosity of the resin molded body 20 and the average diameter of the pores 22 are appropriately selected to match the porosity of the metal porous body 10 and the average diameter of the pores 15. 【0037】 Furthermore, even when performing a defilm removal treatment, by appropriately adjusting the treatment conditions, it is possible to ensure that some of the multiple pores 22 become interconnected pores, while other parts of the multiple pores 22 do not become interconnected pores. 【0038】 In conductive treatment step S2, the surface of the skeleton 21 is subjected to conductive treatment. This conductive treatment is performed, for example, by sputtering tin onto the surface of the skeleton 21. This conductive treatment forms a conductive layer on the surface of the skeleton 21. Furthermore, as a result of the above conductive treatment, a conductive layer is also formed on the surface of the partition wall between two adjacent pores 22. 【0039】 In the plating process S3, an electroplated layer is formed on the conductive layer by applying an electric current to the conductive layer formed in the conductive treatment process S2 and performing electroplating. 【0040】 In the resin molded body removal step S4, the resin molded body 20 is removed. The resin molded body 20 is dissolved and removed using an ionic liquid (e.g., diethanolamine) at a temperature below the melting point of the constituent materials of the conductive layer and plating layer (for example, 175°C if the conductive layer and plating layer are formed of tin). After the removal of the resin molded body 20, the conductive layer and plating layer become the metal layer 12 (separator 17). 【0041】 If the melting points of the constituent materials of the conductive layer and plating layer are high, the resin molded body 20 may be decomposed and removed by heating. In this case, the conductive layer and plating layer are oxidized, so after the resin molded body 20 is removed, a reduction treatment is performed under a reducing atmosphere (for example, under a hydrogen atmosphere). 【0042】 The conductive treatment step S2 may be performed, for example, by applying carbon to the surface of the skeleton 21. In this case, only the plating layer formed in the plating step S3 constitutes the metal layer 12. 【0043】 The method for manufacturing the porous metal body 10 does not necessarily have to include the conductive treatment step S2 and the plating step S3. Figure 7 is a process diagram showing the method for manufacturing the porous metal body 10 according to Modification 1. As shown in Figure 7, the firing layer formation step S5 may be performed instead of the conductive treatment step S2 and the plating step S3. 【0044】 In the firing layer formation step S5, firstly, a paste containing tin particles and a binder is applied to the surface of the skeleton 21 and to the surface of the partition wall between two adjacent pores 22. The binder is, for example, carboxymethylcellulose (CMC). Secondly, the applied paste is fired. This firing is carried out at a temperature below the melting point of tin. As a result, adjacent tin particles in the applied paste neck together and form metallic bonds, and the applied paste becomes a layer of fired tin particles. This layer of fired tin particles becomes the metal layer 12 (partition wall 17) after the resin molded body removal step S4. 【0045】 Figure 8 is a process diagram showing a method for manufacturing a porous metal body 10 according to Modification 2. As shown in Figure 8, the method for manufacturing the porous metal body 10 may include a firing layer formation step S5 instead of the conductive treatment step S2. In this case, the fired tin particle layer becomes a conductive layer, and electroplating is performed in the plating step S3 by passing an electric current through the fired tin particle layer. In this case, after the resin molded body removal step S4, the fired tin particle layer and the plating layer formed in the plating step S3 become the metal layer 12 (separator 17). 【0046】 (Effects of the porous metal 10) The effects of the porous metal 10 will be explained below in comparison with a comparative example. The porous metal related to the comparative example will be referred to as porous metal 10A. The structure of porous metal 10A is the same as that of porous metal 10, except that it does not have partition walls 17. That is, the structure of porous metal 10A is the same as that of porous metal 10, except that all of the pores 15 are interconnected pores. 【0047】 In the porous metal body 10A, when an external load is applied, the load is supported only by the metal skeleton 11. Therefore, the porous metal body 10A is easily deformed by external loads and may have low rigidity. On the other hand, in the porous metal body 10, when an external load is applied, the load is supported not only by the metal skeleton 11 but also by the partition walls 17, making it less susceptible to deformation by the load. Therefore, the porous metal body 10 has improved rigidity. 【0048】 In particular, when the metal framework 11 is formed from a metal material with a Vickers hardness of 50 Hv or less, the porous metal body 10A may have too low rigidity to stand on its own. In the porous metal body 10, the rigidity is improved by the partition walls 17, making it possible to stand on its own even when the metal framework 11 is formed from a metal material with a Vickers hardness of 50 Hv or less. 【0049】 In the porous metal body 10A, all the pores 15 are interconnected. Therefore, when used as a sound insulation material, the sound insulation effect of the porous metal body 10A may be insufficient. On the other hand, in the porous metal body 10, since there are partition walls 17 inside, sound waves are more easily blocked by the partition walls 17, and the sound insulation effect is improved when used as a sound insulation material. 【0050】 The porous metal body 10 may be used as the negative electrode of a nickel-zinc battery or a zinc-air battery. When the tin content of the metal framework 11 and partition wall 17 is 99.9 mass percent or more (99.999 mass percent or more), the hydrogen overpotential of tin is large, making it difficult for hydrogen to be generated as a side reaction on the surface of the negative electrode when the above battery is in operation. In this case, since the metal framework 11 is formed almost entirely of tin, there are fewer starting points for zinc dendrite formation on the surface of the negative electrode, and zinc dendrite formation is suppressed. 【0051】 <Examples> Samples 1 through 3 were prepared as nickel-zinc battery samples. For the positive electrodes of Samples 1 through 3, a metal porous material (nickel porous material) formed of nickel was used. The interior of the nickel porous material was filled with a positive electrode active material slurry. The composition of the positive electrode active material slurry after drying was 90 mass percent nickel hydroxide, 7 mass percent cobalt hydroxide, 0.3 mass percent CMC, and 2.7 mass percent SBR (styrene-butadiene rubber). The fixed component ratio in the positive electrode active material was 78 mass percent. 【0052】 In the preparation of the positive electrodes for Samples 1 to 3, firstly, the thickness was 1.2 mm and the metal content was 300 g / m². 2A nickel porous body was prepared. Secondly, after adjusting the thickness using a roll press, a positive electrode active material slurry was filled into the interior of the nickel porous body. Thirdly, the nickel porous body filled with the positive electrode active material slurry was dried at 100°C and then densified by roll pressing. As a result, a positive electrode with an electrode area of ​​30 mm × 30 mm, a thickness of 0.45 mm, and a calculated capacity of 240 mAh was obtained. Nickel leads were attached to the positive electrode by welding. 【0053】 Sample 1 used a copper porous metal (copper porous metal) as the negative electrode, Sample 2 used a copper porous metal (tin-plated copper porous metal) with a tin-plated surface as the negative electrode, and Sample 3 used a porous metal 10 with a tin content of 99.99 mass percent or more in the metal framework 11 as the negative electrode. The porous metals of Samples 1 to 3 had a metal content of 200 g / m³. 2 The thickness was set to 1.0 mm. The porosity of the porous metal materials in Samples 1 to 3 was 97.8 percent, 97.8 percent, and 97.2 percent, respectively. The porous metal materials used in Samples 1 to 3 are shown in Table 1. 【0054】 In samples 1 to 3, a negative electrode active material slurry was packed into the interior of a porous metal body. The composition of the negative electrode active material slurry after drying was 90 mass percent zinc oxide, 5 mass percent AB (acetylene black), 0.5 mass percent CMC, 1.5 mass percent PTFE (polytetrafluoroethylene), and 3 mass percent SBR. The fixed component ratio in the negative electrode active material was 60 mass percent. 【0055】 [Table 1] 【0056】 In the fabrication of the negative electrodes for Samples 1 to 3, firstly, the porous bodies shown in Table 2 were prepared. Secondly, after adjusting the thickness using a roll press, the negative electrode active material slurry was filled into the interior of the metal porous body. Thirdly, the metal porous body filled with the negative electrode active material slurry was dried at 100°C and then densified by roll pressing. As a result, a negative electrode with an electrode area of ​​30 mm × 30 mm and a calculated capacity of 400 mAh was obtained. Nickel leads were attached to the negative electrode by welding. 【0057】 In Samples 1 to 3, an electrode group was formed by interposing a 150 μm thick anion conductive film as a separator between the positive and negative electrodes. This electrode group was placed inside a polypropylene bag, which was then secured by sandwiching it between acrylic plates from the outside. A 1 mol / L potassium hydroxide aqueous solution with saturated zinc oxide was used as the electrolyte. The electrolyte was supplied into the bag until the electrode group was completely immersed, and the electrode group was also impregnated under reduced pressure. 【0058】 Prior to evaluation, samples 1 through 3 underwent activation. This activation involved, firstly, charging to 1.9V at 0.1C, followed by discharging to 1.5V at 0.1C, repeated three times. Secondly, charging to 1.9V at 0.2C, followed by discharging to 1.5V at 0.2C, repeated three times. Thirdly, charging to 1.9V at 0.5C, followed by discharging to 1.5V at 0.5C, repeated three times. 【0059】 As the first test, the discharge capacity of the negative electrode of samples 1 to 3 was compared. In the first test, the batteries were charged to 1.9V at 0.5C in a constant temperature bath at 30°C. The cutoff time for CV was set to 5 hours or a current value of 10mA. In the first test, the batteries were discharged to 1.5V at 0.2C, 0.5C, and 1C. 【0060】 The results of the first test are shown in Table 2. The discharge capacity shown in Table 2 is the average value for N=5. As shown in Table 2, it was confirmed that sample 3 was functioning correctly. 【0061】 [Table 2] 【0062】 In addition, as a second test, the self-discharge characteristics of the negative electrodes of samples 1 to 3 were evaluated. In the second test, samples 1 to 3 were charged using the same method as in the first test. After charging was complete, samples 1 to 3 were stored in a constant temperature bath at 45°C for 15 days. After this storage, samples 1 to 3 were discharged at 0.2C until the voltage reached 1.5V, and their remaining capacities were compared. 【0063】 The results of the second test are shown in Table 3. The remaining capacity shown in Table 3 is the average value for N=5. As shown in Table 3, the remaining capacity of sample 3 was greater than that of sample 1 and sample 2. From this, it was confirmed that using a porous metal 10 with a tin content of 99.99 mass percent or more in the metal framework 11 as the negative electrode of a nickel-zinc battery results in excellent self-discharge characteristics. 【0064】 [Table 3] 【0065】 Furthermore, as a third test, the cycle characteristics of the negative electrode in samples 1 to 3 were evaluated. In the third test, charging and discharging to 1.5V at 0.5C were repeated using the same method as in the first test. Figure 9 is a graph showing the relationship between the number of charge / discharge cycles and the discharge capacity in samples 1 to 3. The values ​​shown in the graph in Figure 9 were taken as the average value for N=5. As shown in Figure 9, sample 3 showed the least decrease in discharge capacity with increasing number of charge / discharge cycles compared to samples 1 and 2. From this, it was confirmed that using a porous metal 10 with a tin content of 99.99 mass percent or more in the metal framework 11 as the negative electrode of a nickel-zinc battery results in excellent cycle characteristics. 【0066】 Samples 4 and 5 were prepared to evaluate the effect of the presence or absence of partition walls 17 on the strength of the porous metal. In preparing Samples 4 and 5, firstly, foamed polyurethane sheets were prepared. The thickness of the foamed polyurethane sheet was set to 1 mm, and the number of cells per inch of the foamed polyurethane sheet was set to 53 to 58. The foamed polyurethane sheet used for Sample 4 underwent a defilm removal treatment, while the foamed polyurethane sheet used for Sample 5 did not undergo a defilm removal treatment. 【0067】 Secondly, the foamed polyurethane sheet was subjected to a conductive treatment step S2, which involved sputtering with tin. The sputtering was carried out so that the thickness of the sputtered film was 1 μm. Thirdly, the foamed polyurethane sheet was subjected to a plating step S3, which involved plating in an organic acid tin plating bath with a metal content of 200 g / m². 2 Tin plating was performed in such a manner. Fourthly, as resin molded body removal step S4, the foamed polyurethane sheet was dissolved and removed by immersion in diethanolamine at 175°C for 15 minutes. 【0068】 As described above, the foamed polyurethane sheet used in Sample 4 underwent a defilm removal treatment, while the foamed polyurethane sheet used in Sample 5 did not. Therefore, Sample 4 did not have partition walls 17, while Sample 5 did. Details of Sample 4 and Sample 5 are shown in Table 4. The porosity of both Sample 4 and Sample 5 was 97.2 percent. 【0069】 [Table 4] 【0070】 The tensile strength of Sample 4 and Sample 5 was measured by the following method. First, each sample was processed into a test specimen measuring 20 mm wide × 70 mm long × 1 mm thick. Second, a tensile test was performed on the test specimen using a tensile testing machine. In the tensile test, a load was applied along the length of each sample. Third, the maximum tensile load obtained as a result of the tensile test was measured against the apparent cross-sectional area of ​​the test specimen (20 mm × 1 mm = 20 mm²). 2 The tensile strength of each sample was calculated by dividing by ). The tensile strengths of samples 4 and 5 are also shown in Table 4. The tensile strength of sample 5 was higher than that of sample 4. From this comparison, it was confirmed that the tensile strength of the porous metal is improved by the presence of the partition wall 17. 【0071】 The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the embodiments described above, and all modifications within the meaning and scope of equivalents of the claims are intended to be included. [Explanation of symbols] 【0072】 10,10A porous metal body, 11 metal skeleton, 12 metal layer, 12a first layer, 12b second layer, 13 hollow section, 14 cell, 15 pore, 16 hole, 17 partition wall, 20 resin molded body, 21 skeleton, 22 pore, S1 preparation process, S2 conductive treatment process, S3 plating process, S4 resin molded body removal process, S5 firing layer formation process, T1,T2 thickness.

Claims

[Claim 1] A porous metal, Metal frame and The metal frame comprises a partition wall formed integrally with the metal frame from the same material, The aforementioned porous metal contains multiple polyhedral cells, The edges of the polyhedron shape are made of the metal skeleton, A porous metal in which, within the interior of the porous metal, there are locations where the openings of the cells, defined by the edges, are closed off by the partition walls. [Claim 2] The porous metal body according to claim 1, wherein the metal layer constituting the metal skeleton is formed of a metal material having a Vickers hardness of less than 600 Hv. [Claim 3] The porous metal body according to claim 1, wherein the metal layer constituting the metal skeleton is formed of a metal material having a Vickers hardness of 350 Hv or less. [Claim 4] The porous metal body according to claim 1, wherein the metal layer constituting the metal skeleton is formed of a metal material having a Vickers hardness of 100 Hv or less. [Claim 5] The porous metal body according to claim 2, wherein the thickness of the metal layer is 0.3 μm or more and 10 μm or less. [Claim 6] The porous metal body according to claim 2, wherein the metal skeleton is made of tin and has a tin content of 99.99 mass percent or more. [Claim 7] The porous metal body according to any one of claims 1 to 6, wherein the metal layer constituting the metal skeleton consists of a layer of fired tin particles.

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