Metal material

Abstract

To provide a metal material containing a group 5 element having a junction, which can provide an excellent hydrogen separation function.SOLUTION: A metal material, which contains group 5 elements, is used for separating hydrogen from mixed gas including hydrogen, where the metal material has a junction. When junction-contents that are contents of group 5 elements in the junction and non-junction contents that are contents of group 5 elements in a portion other than the junction of the metal material are respectively measured by an SEM-EDX (an energy dispersion-type X-ray spectroscopic method), a ratio of the junction contents / the non-junction contents is set to be in a range of 0.9-1.1.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a metallic material containing a Group 5 element, which is used to separate hydrogen from a hydrogen-containing mixed gas. [Background technology]

[0002] There is known technology relating to a hydrogen separation device that uses a hydrogen-permeable membrane formed from an alloy primarily composed of a non-palladium (Pd)-based metal, such as a metal belonging to Group 5, such as vanadium (V), niobium (Nb), or tantalum (Ta), or a non-palladium (Pd)-based metal (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-5684 A (paragraph 0012) [Non-patent literature]

[0004] [Non-Patent Document 1] Yoshinaga et al., "Development of a large-capacity ultra-high-purity hydrogen separation device using vanadium alloy membranes," Materia, Vol. 57, No. 1 (2018), pp. 23-25. Summary of the Invention [Problem to be solved by the invention]

[0005] In hydrogen separation devices that use hydrogen-permeable membranes (hereinafter sometimes referred to as "metal membranes containing Group 5 elements") formed from non-palladium (Pd)-based metals, such as Group 5 metals such as vanadium (V), niobium (Nb), and tantalum (Ta), or alloys containing non-palladium (Pd)-based metals as the main metal (hereinafter sometimes referred to as "metal materials containing Group 5 elements"), the challenge is to increase the yield per unit time of hydrogen separated from hydrogen-containing mixed gases.

[0006] The present invention was created in consideration of the above problems, and aims to provide a technology that makes it possible to increase the yield per unit time of hydrogen separated from a hydrogen-containing mixed gas. [Means for solving the problem]

[0007] One way to increase the yield per unit time of hydrogen separated from a hydrogen-containing mixed gas is to increase the area of ​​the hydrogen-permeable membrane that comes into contact with the mixed gas. One possible way to increase the area of ​​the hydrogen-permeable membrane is to increase the area by joining a metal membrane containing a Group 5 element by a method such as welding.

[0008] In this regard, a report on welding vanadium membranes has been published in which a 100 mm thick V-10%Fe alloy membrane was rolled into a cylindrical shape and welded to produce a pipe-shaped alloy membrane with a diameter of 6 mm and a length of 80 mm, and both ends of this pipe-shaped alloy membrane were joined with Swagelok joints to produce a pipe-shaped V alloy membrane cell. A hydrogen permeation test was conducted using this cell, introducing pure hydrogen gas at 0.4 MPa into the primary side as the feed gas, and it was reported that 30 L / h of pure hydrogen was obtained by permeation (Non-Patent Document 1).

[0009] However, in Non-Patent Document 1, the primary pressure could only be increased to 0.4 MPa. Furthermore, the hydrogen permeation rate in Non-Patent Document 1 only reached a mere 30 L / h. Therefore, aiming to separate hydrogen at higher pressures, the inventors further investigated the applicability of welding to metal membranes containing Group 5 elements. They found that in order to improve the durability of a metal membrane containing a Group 5 element with a welded joint, including the joint, it is important to ensure that the Group 5 element content ratio is approximately the same between the joint and the non-jointed portion (hereinafter sometimes referred to as the "non-jointed portion"). This is presumably because the incorporation of impurities or element segregation (i.e., uneven chemical composition depending on the location) at the joint makes hydrogen embrittlement more likely to occur during hydrogen permeation.

[0010] The present invention has been made in view of the above.

[0011] The present invention relates to a metallic material containing a Group 5 element, which is used to separate hydrogen from a hydrogen-containing mixed gas, and characterized in that the metallic material has a bonded portion, and when the bonded portion content, which is the content of the Group 5 element in the bonded portion, and the non-bonded portion content, which is the content of the Group 5 element in the portion of the metallic material other than the bonded portion, are each measured by SEM-EDX (energy dispersive X-ray spectroscopy), the bonded portion content / non-bonded portion content is in the range of 0.9 to 1.1.

[0012] In the present invention, the metal material preferably has the form of a metal film or a metal tube.

[0013] In the present invention, the thickness of the metal film or the wall thickness of the metal pipe is preferably 0.05 mm or more and 5 mm or less.

[0014] In the present invention, the Group 5 metal is preferably at least one selected from the group consisting of vanadium, niobium, and tantalum.

[0015] In the present invention, the metal material containing the Group 5 element is preferably pure vanadium or a vanadium alloy. [Effects of the Invention]

[0016] It is possible to provide a metal material containing a Group 5 element having a joint, which can provide good hydrogen separation function. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram of an electron beam welding apparatus and a schematic diagram showing two vanadium films (plates) placed on a workpiece during electron beam welding in Example 1. [Figure 2] FIG. 2 shows photographs of the SEM observation fields of the non-bonded portion and the bonded portion in Example 1. [Figure 3]FIG. 3 shows the measurement results of the hydrogen permeation performance of the vanadium membrane (disk-shaped membrane with a diameter of 52 mm) whose center was electron-beam welded in Example 1 and a normal vanadium membrane (disk-shaped membrane with a diameter of 52 mm) without this welding, and a schematic diagram of the measurement sample (vanadium membrane whose center was electron-beam welded) used in the measurement. [Figure 4] FIG. 4 is a schematic diagram of a fiber welding device and a schematic diagram showing two vanadium films (plates) placed on a workpiece during fiber welding in Example 2. [Figure 5] FIG. 5 shows the measurement results of the hydrogen permeation performance of the vanadium membrane (disk-shaped membrane with a diameter of 52 mm) fiber-welded at the center in Example 2 and a normal vanadium membrane (disk-shaped membrane with a diameter of 52 mm) without this welding. [Figure 6] FIG. 6 is a conceptual diagram of the experimental device used in the hydrogen permeation test. DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments for carrying out the present invention will be described below. Note that the following embodiments do not limit the inventions according to the claims, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention. Furthermore, it goes without saying that the following embodiments may be modified as appropriate within the scope of the gist of the present invention.

[0019] The metallic material of the present invention is used to separate hydrogen from a hydrogen-containing mixed gas and contains a Group 5 element. The metallic material has a bonded portion. When the bonded portion content, which is the content of the Group 5 element in the bonded portion, and the non-bonded portion content, which is the content of the Group 5 element in the portion of the metallic material other than the bonded portion, are measured by SEM-EDX (energy dispersive X-ray spectroscopy), the bonded portion content / non-bonded portion content ratio is in the range of 0.9 to 1.1. That is, the present invention has found that it is preferable to control the content of the Group 5 element in the bonded portion (bonded portion content) and the content of the Group 5 element in the portion of the metallic material (base metallic material) other than the bonded portion (non-bonded portion content) so that they are substantially the same. By performing such control, the bonded portion and the non-bonded portion can be considered to be in almost the same state from the perspective of hydrogen permeation, minimizing the difference in hydrogen permeability and minimizing hydrogen embrittlement.

[0020] The metallic material of the present invention is used to separate hydrogen from a hydrogen-containing mixed gas. Specifically, the mixed gas contacts one surface of the metallic material, hydrogen diffuses from the mixed gas into the metallic material, and is released from the other surface, thereby permeating the metallic material. Generally, hydrogen atoms diffuse faster in metals than other atoms, so hydrogen can be extracted by permeating the metallic material. The form of such a metallic material is not particularly limited, but it is preferably in the form of a metallic membrane or metallic tube. When using a metallic membrane, hydrogen can be separated from a mixed gas by permeating hydrogen from the front surface to the back surface of the membrane. When using a metallic tube, hydrogen can be separated from a mixed gas by permeating hydrogen from the outer surface of the cylindrical metallic tube to the inner surface of the cylinder, or from the inner surface of the cylindrical metallic tube to the outer surface of the cylinder. Furthermore, when using a metallic tube, either the top or bottom surface of the cylinder may be sealed with a metallic membrane containing the same Group 5 element. This means that either the top or bottom surface of the cylinder is covered with a metallic membrane containing the same Group 5 element (hereinafter referred to as a "metal membrane lid"). This allows hydrogen to permeate from the inner surface of the metal tube cylinder and the inner surface of the metal film lid to the outer surface of the cylinder and the outer surface of the metal film lid, or from the outer surface of the cylinder and the outer surface of the metal film lid to the inner surface of the metal tube cylinder and the inner surface of the metal film lid.

[0021] The metal material of the present invention contains a Group 5 element. This is because metal materials containing a Group 5 element have the excellent property of selectively separating and allowing hydrogen to permeate from mixed gases. Examples of metal materials containing a Group 5 element include non-palladium (Pd)-based metals, more specifically, Group 5 metals such as vanadium (V), niobium (Nb), and tantalum (Ta), or alloys primarily containing non-palladium (Pd)-based metals. More specifically, the Group 5 element is preferably at least one selected from the group consisting of vanadium, niobium, and tantalum, with vanadium being even more preferred. Group 5 elements typified by vanadium, particularly so-called vanadium group elements, have similar chemical properties. Since vanadium has the property of permeating hydrogen, other Group 5 elements, particularly vanadium group elements, also have similar properties. Furthermore, although a Group 5 element is used in the metal membrane in the present invention, Group 5 elements may be used in combination because, as described above, they have similar chemical properties. For example, vanadium may be coexisted with niobium or tantalum, or an alloy thereof may be used.

[0022] Furthermore, the metallic material of the present invention may contain elements other than Group 5 elements. The inclusion of such elements facilitates the imparting of various properties to the metallic material. Examples of such elements include iron (Fe), ruthenium (Ru), aluminum (Al), tungsten (W), molybdenum (Mo), chromium (Cr), and cobalt (Co). The use of these alloying elements facilitates the imparting of rigidity to metallic materials (e.g., hydrogen separation membranes) and suppresses the hydrogen solid solubility (also known as hydrogen solubility) in the alloy even under increased hydrogen pressure, thereby contributing to improved hydrogen embrittlement resistance. The content of elements other than Group 5 elements is typically 0.1 atomic % or more, preferably 1 atomic % or more, for each element. This range facilitates the imparting of the above-described properties to the metallic membrane. Meanwhile, the content of elements other than Group 5 elements is typically 50 atomic % or less, preferably 40 atomic % or less, and more preferably 11 atomic % or less, for each element. Within this range, the benefits of using a Group 5 element are not diminished and the required properties can be easily imparted.

[0023] In the metal material of the present invention, the metal material containing a Group 5 element is preferably pure vanadium or a vanadium alloy, taking into consideration the balance between hydrogen permeability and hydrogen embrittlement resistance. In principle, pure vanadium refers to a metal material containing 100 atm% vanadium. However, metal materials containing unavoidable impurities in vanadium are also included in the concept of "pure vanadium."

[0024] The content of Group 5 elements and other elements in metallic materials can be analyzed using the following method: a scanning electron microscope equipped with EDS or WDS (SEM / EDS / WDS) or a field emission scanning electron microscope (FE-SEM / EDS / WDS) can be used to analyze the type and composition of contained elements by setting appropriate analytical conditions.

[0025] When a metal film or metal tube is used as the metal material of the present invention, the thickness of the metal film or the wall thickness of the metal tube is preferably 0.05 mm or more. Generally, the thicker the metal film or the metal tube, the greater the mechanical strength, making it less susceptible to fracture and allowing hydrogen to permeate over a long period of time. On the other hand, increasing the thickness of the metal film or the metal tube tends to decrease the amount of hydrogen that can permeate per unit time. Therefore, the thickness of the metal film or the wall thickness of the metal tube must be appropriately controlled. From these perspectives, the thickness of the metal film or the wall thickness of the metal tube is preferably 0.1 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more, and particularly preferably 0.5 mm or more, while typically 5 mm or less, preferably 1 mm or less. The thickness of the metal film or the wall thickness of the metal tube can be measured using known measuring devices such as a finger, vernier caliper, micrometer, or 3D shape measuring device, depending on the thickness.

[0026] The metallic material of the present invention has a joint. The term "joint" refers to the joint between metallic materials, i.e., the portion where the metallic materials are joined together. The joining method is not particularly limited, but welding is preferably used in the present invention. From the viewpoint of making the content ratio of Group 5 elements in the joint and the non-joined portion approximately the same, that is, from the viewpoint of controlling the composition difference between the joint and the non-joined portion within a certain range, it is preferable to directly join the metallic materials together without using solder or brazing filler during welding.

[0027] There are no particular limitations on the welding method. Examples include pressure welding, which applies mechanical pressure to the joint between metal materials; fusion welding, which heats the joint between metal materials to a temperature above their melting points; and brazing, which melts a filler metal (solder or brazing filler) with a lower melting point than the metal materials to join them without melting them. Among these, pressure welding or fusion welding are preferred from the viewpoint of controlling the composition difference between the joint and non-joined portions within a certain range, and industrially, fusion welding is preferred. Furthermore, among fusion welding methods, electron beam welding, laser welding, and TIG welding are preferred from the viewpoint of controlling the composition difference between the joint and non-joined portions within a certain range. Furthermore, considering that thin plates such as hydrogen-permeable membranes are being welded, electron beam welding or laser welding is more preferred as the welding method. Furthermore, when using electron beam welding, it is preferable to perform welding in a vacuum. Welding in a vacuum makes it easier to control the composition difference between the joint and non-joined portions within a certain range. Furthermore, when laser welding is used, it is more preferable to use a solid-state laser, and it is preferable to use fiber welding using a fiber laser, from the viewpoint of realizing high-precision, high-density welding.

[0028] The detailed conditions for welding are appropriately controlled so that impurities do not produce modified products during welding, from the viewpoint of making the content ratio of Group 5 elements in the joint and non-joint parts approximately the same, in other words, from the viewpoint of controlling the composition difference between the joint and non-joint parts within a certain range.

[0029] In the present invention, when the bonded portion content, which is the content of Group 5 elements in the bonded portion, and the non-bonded portion content, which is the content of Group 5 elements in the portion of the metal material other than the bonded portion, are measured by SEM-EDX (energy dispersive X-ray spectroscopy), the bonded portion content / non-bonded portion content is set to be in the range of 0.9 to 1.1.

[0030] Here, as described above, the term "joint" refers to the interface between metal materials, or the portion where the metal materials are joined together. Therefore, when elemental analysis is performed with EDX in the observation field while observing with an SEM (scanning electron microscope) using SEM-EDX (energy dispersive X-ray spectroscopy) to perform elemental mapping, the observation field can be set to the joint (or the welded portion in the case of welding), and the joint content can be measured. On the other hand, "portions of metal materials other than the joint" literally refer to portions of the metal material other than the joint, i.e., the base portion of the metal material that is not affected by welding or the like. Therefore, when measuring the non-joint content, the observation field in SEM-EDX (energy dispersive X-ray spectroscopy) can be set to a portion of the base metal material that is far from the joint and is determined to be unaffected by welding or the like.

[0031] The SEM-EDX (energy dispersive X-ray spectroscopy) analytical equipment can be any of those sold by analytical equipment manufacturers. For example, a JEOL JSM-7100F and an Oxford Instruments x-act series can be used in combination for analysis. The analytical conditions for SEM-EDX (energy dispersive X-ray spectroscopy) are, for example, an acceleration voltage of 15 kV, a probe current of 13 nA, a working distance of 10 mm, and 100 frames.

[0032] In the present invention, the bonded portion content / non-bonded portion content ratio is set to a range of 0.9 to 1.1. By controlling the bonded portion content relative to the non-bonded portion content (the content in the metal material in its elemental state) within the above-mentioned deviation range, the Group 5 element content ratio in the bonded portion and the non-bonded portion can be made substantially identical. Ideally, the Group 5 element content ratio in the bonded portion and the non-bonded portion is set to 1.0, i.e., the Group 5 elements in the bonded portion and the non-bonded portion are identical. However, Group 5 elements are easily oxidized, making it difficult to completely eliminate the inclusion of other elements, including oxygen, during welding. Considering the above, the lower limit of the bonded portion content / non-bonded portion content is set to 0.9. This is because, even when using a welding technique that incorporates the most impurities during welding, the lower limit is 0.85, but a stricter standard is required to prevent hydrogen embrittlement of the joined material. From the perspective of making the composition of the bonded portion and the non-bonded portion closer, the bonded portion content / non-bonded portion content ratio is more preferably 0.93 or more, and even more preferably 0.95 or more. Furthermore, when an alloy of a Group 5 element and other elements is used as a metallic material, various variations in the alloy composition are possible. Taking such variations into consideration, the upper limit of the bonded portion content / non-bonded portion content ratio is set to 1.1. On the other hand, the bonded portion content / non-bonded portion content ratio is more preferably set to 1.07 or less, and even more preferably set to 1.05 or less.

[0033] EDX analysis has been reported to vary from measurement to measurement, with a standard deviation (σ) of 2.53%. Assuming that the measurement variation follows a Gaussian distribution, the ±3σ range, which includes 99.7% of the measurement data, is ±2.53 × 3 = ±7.59%. Therefore, even if the Group 5 element content ratio between the bonded and non-bonded portions is ideally 1.0, the EDX analysis value may vary between 0.9241 and 1.0759. Therefore, considering the data variation, it is preferable to control the SEM-EDX (energy dispersive X-ray spectroscopy) analysis value within a ±10% range. A preferable range is ±8%. This indicates that if the analysis value is within the range of 0.9241 to 1.0759, it can be considered that the bonded portion is virtually free of impurities.

[0034] In the present invention, the hardness of the bonded portion generally tends to be softer than that of the non-bonded portion (the portion of the base metal material). This is thought to be because the bonded portion melts during welding, resulting in an effect similar to annealing. However, from the viewpoint of the strength of the film itself, the Vickers hardness of the bonded portion is preferably 30 HV or higher, more preferably 50 HV or higher, even more preferably 60 HV or higher, and particularly preferably 70 HV or higher.

[0035] On the other hand, the Vickers hardness of the non-jointed portion (the portion of the base metal material) is preferably 80 HV or higher. This range softens the metal material, making it easier to ensure toughness. On the other hand, from the viewpoint of hardening the metal material and ensuring mechanical strength, the Vickers hardness is preferably 100 HV or higher, more preferably 120 HV or higher, particularly preferably 130 HV or higher, and most preferably 150 HV or higher. The Vickers hardness of metal materials is generally 500 HV or lower, usually 300 HV or lower. The Vickers hardness may be measured using a commercially available Vickers hardness tester (for example, a micro Vickers hardness tester (for example, the HM-100 series from Mitutoyo Corporation)).

[0036] [Variations] While the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope of the above-described embodiments. Various modifications and improvements can be made to the above-described embodiments. [Example]

[0037] [Example 1] (Electron Beam Welding) Two 0.3 mm thick pure vanadium films (plates) were prepared as metallic materials containing Group 5 elements and were welded using an electron beam. Figure 1 is a schematic diagram of the electron beam welding equipment and a schematic diagram showing the appearance of the two vanadium films (plates) placed on the workpiece during electron beam welding. Electron beam welding was carried out under reduced pressure in the vacuum chamber of the electron beam welding equipment shown in the left diagram of Figure 1. The conditions were as follows: Electron beam processing machine: EBM-6LB-1VR (Mitsubishi Electric Corporation) Processing conditions: Cathode diameter φ2 mm, acceleration voltage 60 kV, WD 300 mm, beam current 35.0 mA

[0038] (Vickers hardness) The Vickers hardness of the welded joint and non-jointed joint (the raw part of the metal material not affected by welding) was measured. The results showed that the Vickers hardness of the welded joint was 90HV, and the Vickers hardness of the non-jointed joint was 120HV. The Vickers hardness measurements were carried out as follows:

[0039] A micro Vickers hardness tester (model number: HM-102) manufactured by Mitutoyo Corporation was used. The Vickers hardness test involves pressing a pyramidal diamond indenter against the sample, observing the resulting indentation under a microscope, and measuring the length of the diagonal to determine the hardness. The Vickers hardness test is excellent for measuring the hardness of thin samples, as the indentation is small, at a maximum of 1 mm or less. Furthermore, measurements were performed after polishing the measurement surface of the sample.

[0040] (SEM observation of bonded and non-bonded parts) The bonded and non-bonded areas were observed using an SEM. A JSM-7100F manufactured by JEOL Ltd. was used for the SEM observation, and secondary electron images were obtained at an accelerating voltage of 15 kV. The observation results are shown in Figure 2. Figure 2 shows images of the SEM observation field of the non-bonded area (secondary electron image labeled "inside non-bonded area" in Figure 2) and the bonded area (secondary electron image labeled "inside bonded area" in Figure 2). As can be seen from the figure, there is no difference between the bonded and non-bonded areas when observed visually.

[0041] (SEM-EDX (energy dispersive X-ray spectroscopy) measurement of bonded and non-bonded parts) SEM-EDX measurements were performed on the bonded and unbonded areas. Measurements were performed using a JEOL JSM-7100F and an Oxford Instruments x-act series. The analytical conditions for SEM-EDX (energy dispersive X-ray spectroscopy) were an acceleration voltage of 15 kV, a probe current of 13 nA, a working distance of 10 mm, and 100 frame accumulations.

[0042] The elemental mapping results for the joint (weld) were as follows: V:98.2% by mass O: 0.8% by mass C: 0.9% by mass Si: 0.1% by mass N and Al were not detected.

[0043] The elemental mapping results for the non-bonded area were as follows: V:97.6% by mass O: 1.3% by mass C: 1.0% by mass Si: 0.1% by mass N and Al were not detected.

[0044] From the above, the ratio of the content of vanadium (V), which is a Group 5 element, that is, the content in the bonded portion / the content in the non-bonded portion, was 1.01 (1% deviation).

[0045] (Hydrogen permeation test) 3 shows the results of measuring the hydrogen permeability of the vanadium membrane (cut into a disk-shaped membrane with a diameter of 52 mm) whose center was electron-beam welded in Example 1 and a normal vanadium membrane (a disk-shaped membrane with a diameter of 52 mm) without welding, as well as a schematic diagram of the measurement sample (vanadium membrane whose center was electron-beam welded) used in the measurement. The hydrogen permeation test was carried out according to the following procedure.

[0046] The vanadium film with the center electron beam welded and the normal vanadium film were RF sputtered for 6 minutes at a substrate temperature of 300°C using an RF sputtering device, and both sides of the film were coated with Pd-25mol%Ag to impart hydrogen dissociation catalytic properties.

[0047] Figure 6 shows a schematic diagram of the experimental equipment used in the hydrogen permeation test. In the area marked "hydrogen permeable membrane" in this diagram, either (1) an RF sputtered vanadium membrane with its center electron beam welded or (2) a regular vanadium membrane was placed, and the entire equipment was evacuated. The amount of hydrogen permeated was measured with a flow meter while the pressure of the mixed gas on the primary side was adjusted as needed.

[0048] When the vanadium membrane with its center electron beam welded was placed in the location marked "hydrogen-permeable membrane" in Figure 6, the electron beam weld shown on the right side of Figure 3 was positioned perpendicular to the flow of the primary mixed gas (in other words, the primary mixed gas was exposed from left to right to the vanadium membrane with its center electron beam welded). The hydrogen permeation test was conducted at a test temperature of 350°C, and the hydrogen gas supply pressure was in the range of 0.1 to 0.7 MPa abs. The hydrogen gas outlet pressure was controlled by vacuuming with a pump. In Figure 3, the vertical axis represents the hydrogen permeation rate per minute (L (SLM)), and the horizontal axis represents the hydrogen gas supply pressure on the input (primary) side.

[0049] As can be seen from the graph in Figure 3, there is no difference in hydrogen permeability between electron-beam welded vanadium membranes and non-electron-beam welded (normal vanadium membranes with no joints) up to an absolute pressure of 0.5 MPa on the primary side. However, in the non-electron-beam welded (normal vanadium membranes with no joints) membrane cracks occurred when the absolute pressure of the primary side gas reached around 0.55 MPa. On the other hand, the electron-beam welded vanadium membrane was able to permeate hydrogen well up to an absolute pressure of 0.7 MPa on the primary side without any cracks occurring.

[0050] Furthermore, the electron beam welded vanadium membrane had a primary gas absolute pressure of 0.7 MPa and a secondary gas flow rate (Outlet gas flow rate, Q) of 1.65 SLM. 1.65 SLM means 1.65 L / min, which means that a hydrogen permeation rate of 99 L / h was achieved. Considering that the hydrogen permeation rate in Non-Patent Document 1 was only about 30 L / h, this means that the present invention achieved a hydrogen permeation rate more than three times that of conventional technology.

[0051] Using the equipment shown in Figure 6, the durability of the electron beam welded vanadium film was confirmed under conditions of a primary gas absolute pressure of 0.2 MPa and a test temperature of 350°C. As a result, even after operating the equipment continuously for 60 hours, no cracking of the electron beam welded vanadium film was observed.

[0052] [Example 2] (Fiber welding) Two 0.3 mm thick pure vanadium films (plates) were prepared as metallic materials containing Group 5 elements and were welded using an electron beam. Figure 4 shows a schematic diagram of the fiber welding equipment and the appearance of the two vanadium films (plates) placed on the workpiece during fiber welding. Fiber welding was carried out in air under appropriately set welding conditions.

[0053] (Vickers hardness) The Vickers hardness of the welded joint and non-jointed joint (the bare part of the metal material not affected by welding) was measured in the same manner as in Example 1. As a result, the Vickers hardness of the welded joint was 90 HV, and the Vickers hardness of the non-jointed joint was 140 HV.

[0054] (SEM-EDX (energy dispersive X-ray spectroscopy) measurement of bonded and non-bonded parts) SEM-EDX measurement was carried out on the bonded portion and non-bonded portion in the same manner as in Example 1. As a result, the element mapping results for the bonded portion (welded portion) were as follows. V:93.8% by mass O: 4.2% by mass C: 1.3% by mass Al: 0.7 mass% (presumably derived from vanadium raw material) Si: 0.1% by mass N was not detected.

[0055] The elemental mapping results for the non-bonded area were as follows: V:92.4% by mass O: 5.6% by mass C: 1.3% by mass Al: 0.7 mass% (presumably derived from vanadium raw materials) Si: 0.1% by mass N was not detected.

[0056] From the above, the ratio of the content of vanadium (V), which is a Group 5 element, that is, the content in the bonded portion / the content in the non-bonded portion, was 1.02 (a deviation of 2%).

[0057] (Hydrogen permeation test) A hydrogen permeation test was conducted in the same manner as in Example 1. Figure 5 shows the results of measuring the hydrogen permeation performance of a vanadium membrane (disk-shaped membrane with a diameter of 52 mm) fiber-welded at the center in Example 2 and a standard vanadium membrane (disk-shaped membrane with a diameter of 52 mm) without this welding. For the vanadium membrane fiber-welded at the center, a sample with the same shape as in Example 1 was used for the measurement. As can be seen from the graph in Figure 5, the hydrogen permeation test was performed well on the vanadium membrane fiber-welded up to an absolute gas pressure of more than 0.4 MPa and up to 0.5 MPa on the primary side. In Example 2, even the vanadium membrane without fiber welding (standard with no joints) did not experience the phenomenon of membrane cracking up to an absolute gas pressure of 0.5 MPa on the primary side. However, the results showed that the vanadium membrane fiber-welded generally had better hydrogen permeation performance than the vanadium membrane without fiber welding (standard with no joints).

[0058] Furthermore, the fiber-welded vanadium membrane has a primary gas absolute pressure of 0.5 MPa and a secondary gas flow rate (Outlet gas flow rate, Q) of 1.6 SLM. 1.6 SLM means 1.6 L / min, which means that a hydrogen permeation rate of 96 L / h was achieved. Considering that the hydrogen permeation rate in Non-Patent Document 1 was only about 30 L / h, this means that the present invention has achieved a hydrogen permeation rate more than three times that of conventional technology.

[0059] Using the equipment shown in Figure 6, the durability of the fiber-welded vanadium membrane was confirmed under conditions of a primary gas absolute pressure of 0.2 MPa and a test temperature of 350°C. As a result, no cracking of the fiber-welded vanadium membrane was observed even after 60 hours of continuous operation of the equipment.

[0060] [Example 3] (TIG welding) Two 0.2 mm thick pure vanadium films (plates) were prepared as metal materials containing Group 5 elements and were TIG welded (arc welding using a tungsten electrode and inert gas). The placement on the workpiece and the welding locations during welding were the same as in Examples 1 and 2.

[0061] (SEM-EDX (energy dispersive X-ray spectroscopy) measurement of bonded and non-bonded parts) SEM-EDX measurement was carried out on the bonded portion and non-bonded portion in the same manner as in Example 1. As a result, the element mapping results for the bonded portion (welded portion) were as follows. V:96.62% by mass C: 3.38% by mass

[0062] The elemental mapping results for the non-bonded area were as follows: V:89.04% by mass C: 10.79% by mass Si:0.17% by mass

[0063] From the above, the ratio of the content of vanadium (V), which is a Group 5 element, that is, the content in the bonded portion / the content in the non-bonded portion, was 1.085 (8.5% deviation). [Industrial Applicability]

[0064] The present invention provides a metal material containing a Group 5 element having a joint, which can provide good hydrogen separation function.

Claims

1. A metal material containing a Group 5 element, which is used to separate hydrogen from a mixed gas containing hydrogen, the metal material has a weld; A metallic material characterized in that, when a bond content, which is the content of the Group 5 element in the bonded portion, and a non-bonded content, which is the content of the Group 5 element in a portion of the metallic material other than the bonded portion, are each measured by SEM-EDX (energy dispersive X-ray spectroscopy), the bond content / non-bonded content is in the range of 0.9 to 1.

1.

2. The metallic material according to claim 1 , wherein the metallic material is in the form of a metallic film or a metallic tube.

3. 3. The metallic material according to claim 2, wherein the thickness of the metallic film or the wall thickness of the metallic tube is 0.05 mm or more and 5 mm or less.

4. The metallic material according to claim 1 , wherein the Group 5 metal is at least one selected from the group consisting of vanadium, niobium, and tantalum.

5. The metallic material according to claim 1 , wherein the metallic material containing a Group 5 element is pure vanadium or a vanadium alloy.

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