Structures and hydrogen storage structures

Abstract

To inhibit an aggregation of a plurality of particles each containing a hydrogen storage metal element.SOLUTION: In a structure, a plurality of particles each containing hydrogen storage metal element are disposed in a manner alienated with each other in a stationary member. An entirety of a surface of each of the plurality of particles is surrounded by the stationary member. The stationary member contains at least one of an oxide and a nitride. The stationary member includes a base and a film disposed on a surface of the base. The plurality of particles include two or more particles disposed on the surface of the base and each having a different distance from the surface of the base. The film is abutting on an entire surface of the plurality of particles.SELECTED DRAWING: Figure 1

Description

Technical Field

[0006] , , ,

[0001] The present invention relates to a structure and a hydrogen storage structure.

Background Art

[0002] A hydrogen storage metal or a hydrogen storage alloy can be used as a means for storing hydrogen. Patent Document 1 describes a method for producing a hydrogen storage alloy. In this production method, an rf arc plasma is formed in a vacuum vessel under reduced pressure, and the vapors of Ti and Cu, or Ti, Cu and Si are reacted in the plasma to form and recover fine powders of a Ti-Cu alloy or a Ti-Cu-Si alloy. According to Patent Document 1, the fine powders produced by this production method have a large surface area, and thus a hydrogen storage amount about 10 to 50 times that of the conventional ones is realized.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Particles containing a hydrogen storage metal element such as a hydrogen storage metal and a hydrogen storage alloy can generate heat when storing hydrogen. In particular, as the dimensions of the particles are reduced to increase the surface area per unit volume, the hydrogen storage efficiency is improved, and the amount of heat generated when storing hydrogen can also increase. When the amount of heat generated becomes large, the particles can aggregate. Alternatively, the particles can also aggregate even when heat is externally applied to the particles. When the particles aggregate, the hydrogen storage ability can decrease.

[0005] An object of the present invention is to suppress the aggregation of a plurality of particles containing a hydrogen storage metal element.

Means for Solving the Problems

[0006] A first aspect of the present invention relates to a structure in which a plurality of particles containing a hydrogen-absorbing metal element are arranged in a fixed member such that they are separated from each other, wherein the surfaces of the plurality of particles are surrounded by the fixed member, and the fixed member is made of MgO, ZrO 2 、Y 2 O 3 CaO, Al 2 O 3 Si 3 N 4 The fixing member comprises at least one of AlN and a substrate, and the fixing member comprises a substrate and a plurality of films disposed on the surface of the substrate, the plurality of films are laminated so that films of the same material are in contact with each other, and the plurality of particles comprises particles disposed on the surface of the substrate and particles that are not on the surface of the substrate. A second aspect of the present invention relates to a structure in which a plurality of particles containing a hydrogen-absorbing metal element are arranged in a fixed member such that they are separated from each other, the surfaces of the plurality of particles are surrounded by the fixed member, the fixed member includes a base and a film disposed on the surface of the base, the film being MgO, ZrO 2 、Y 2 O 3 CaO, Al 2 O 3 and Si 3 N 4 The material comprises at least one of the plurality of particles, wherein the plurality of particles in the film include two or more particles that are at different distances from the surface of the substrate. A third aspect of the present invention relates to a heat generation method for generating heat by causing hydrogen to be absorbed into a structure, wherein the structure is a structure in which a plurality of particles containing a hydrogen-absorbing metal element are arranged in a fixed member such that they are separated from each other, the surfaces of the plurality of particles are surrounded by the fixed member, the fixed member includes a base and a film disposed on the surface of the base, the film is made of MgO, ZrO 2 、Y 2 O 3 CaO, Al 2 O 3 Si 3 N 4 The material is composed of at least one of AlN, and the plurality of particles have a structure in which the plurality of particles include two or more particles that are at different distances from the surface of the substrate within the film, and the plurality of particles are arranged in the fixing member such that the plurality of particles are separated from each other, thereby suppressing aggregation of the plurality of particles, and generating heat by allowing the plurality of particles to absorb hydrogen. [Effects of the Invention]

[0007] According to the present invention, aggregation of multiple particles containing hydrogen-absorbing metal elements is suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic cross-sectional view of the structure according to the first embodiment of the present invention. [Figure 2] A schematic cross-sectional view of the structure according to the first embodiment of the present invention. [Figure 3A] A diagram illustrating a method for manufacturing a structure according to the first embodiment of the present invention. [Figure 3B] A diagram illustrating a method for manufacturing a structure according to the first embodiment of the present invention. [Figure 3C] A diagram illustrating a method for manufacturing a structure according to the first embodiment of the present invention. [Figure 3D] A diagram illustrating a method for manufacturing a structure according to the first embodiment of the present invention. [Figure 4A] TEM image of a cross-section of the structure according to the embodiment. [Figure 4B] TEM image of a cross-section of the structure according to the embodiment (enlarged view of Figure 4A). [Figure 5A] TEM image of a cross-section of a structure after heat treatment. [Figure 5B] TEM image of the cross-section of the structure after heat treatment (enlarged view of FIG. 5A). [Figure 6A] Diagram showing the results of EDX analysis of the structure of FIG. 4A. [Figure 6B] Diagram showing the results of EDX analysis of the structure of FIG. 5A. [Figure 7] Schematic cross-sectional view of the structure of the second embodiment of the present invention. [Figure 8] Schematic cross-sectional view of the structure of the third embodiment of the present invention. [Mode for Carrying Out the Invention]

[0009] Hereinafter, the present invention will be described through its exemplary embodiments with reference to the accompanying drawings.

[0010] [First Embodiment] In FIGS. 1 and 2, schematic cross-sectional views of the structure 1 of the first embodiment of the present invention are shown. Here, FIG. 2 corresponds to an enlarged view of a part of the cross-section along the line A-A' of FIG. 1. The structure 1 has a structure in which a plurality of particles 3 are arranged in a fixing member 10 so as to be separated from each other.

[0011] The fixing member 10 functions to keep the plurality of particles 3 separated from each other even in a high-temperature environment, and for example, functions to fix the positions of the plurality of particles 3. Each of the plurality of particles 3 contains a hydrogen storage metal element. The fixing member 10 may include, for example, a base 2 and a film 4 disposed on the base 2. The entire surface of each of the plurality of particles 3 is surrounded by the fixing member 10.

[0012] Particle 3 is a particle composed of a material containing a hydrogen-absorbing metal element, and may include, for example, at least one of hydrogen-absorbing metal particles and hydrogen-absorbing alloy particles. The hydrogen-absorbing metal element may be, for example, at least one selected from the group consisting of Pd, Ni, Cu, Ti, Nb, Zr, Mg, Mn, V, Fe, and rare earth elements. The hydrogen-absorbing alloy may be, for example, at least one selected from the group consisting of Pd / Ni alloy, Pd / Cu alloy, Mg / Zn alloy, Zr / Ni alloy, Zr / Ni / Mn alloy, Ti / Fe alloy, Ti / Co alloy, La / Ni alloy, Re / Ni alloy, Mm / Ni alloy, Ca / Ni alloy, Ti / V alloy, Ti / Cr alloy, Ti / Cr / V alloy, Mg / Ni alloy, and Mg / Cu alloy. The dimensions of each of the multiple particles 3 may be, for example, 2 nm or more and 1000 nm or less. In terms of increasing the total surface area of ​​the multiple particles 3, the dimensions of each of the multiple particles 3 are preferably 2 nm or more and 100 nm or less, and more preferably 2 nm or more and 10 nm or less. The particles 3 are preferably crystalline, and may be single crystals or polycrystalline.

[0013] The film 4 may be composed of a high-melting-point material, for example, a material with a melting point of 1400°C or higher. The film 4 may contain multiple microcrystals, but may also be amorphous. The film 4 may contain, for example, at least one of oxides (e.g., at least one of MgO, ZrO2, ZrO2·Y2O3, CaO, SiO2, and Al2O3) and at least one of nitrides (e.g., at least one of Si3N4 and AlN).

[0014] The substrate 2 may be, for example, a Si substrate or a substrate on which an SiO2 film is formed, but it may also be composed of other materials (e.g., metal or insulator). Preferably, the substrate 2 is composed of a material having a melting point of 1400°C or higher. The substrate 2 may be a film or other component made of the same material as the film 4, or it may be a film or other component made of a different material than the film 4. The substrate 2 may be a self-supporting component or a component supported by other components.

[0015] If there is no film 4 made of a high-melting-point material that separates multiple particles 3 from each other, when particles 3 absorb hydrogen and generate heat, the heat can cause two or more nearby particles 3 to aggregate. This can increase the size of individual particles and reduce their hydrogen absorption capacity. The presence of a film 4 made of a high-melting-point material that separates multiple particles 3 from each other suppresses the aggregation of two or more nearby particles 3 caused by the heat generated when particles 3 absorb hydrogen. Furthermore, the presence of a film 4 made of a high-melting-point material also suppresses the formation of an alloy between the particles 3 and the constituent material of the film 4 due to the heat generated when particles 3 absorb hydrogen. The heat resistance required for the film 4 is sufficient to prevent melting when the structure 1 generates heat. The temperature of the structure 1 when it generates heat depends on the material of the particles 3, the density of the particles 3 in the structure 1, the hydrogen isotope gas pressure, etc., and therefore cannot be uniformly specified. For this reason, it is desirable to appropriately select the material of the film 4 according to the usage environment, but for example, it should be a material with a melting point of 1400°C or higher. The distance between the multiple particles 3 separated by the fixing member 10 is preferably 1 nm or more and 10 nm or less. This is because an increase in the distance between the multiple separated particles 3 would decrease the content of hydrogen-absorbing metal or hydrogen-absorbing alloy in the structure 1, which is undesirable.

[0016] The multiple particles 3 may include particles 3' arranged two-dimensionally along the surface of the substrate 2 so as to be in contact with the surface of the substrate 2. The particles 3' are arranged apart from each other via a film 4 and are covered by the film 4.

[0017] The manufacturing method for structure 1 may include a first step of forming a plurality of particles 3, each containing a hydrogen-absorbing metal element, spaced apart from one another, as illustrated in Figure 3A, and arranging the individual particles 3 in an island-like manner, and a second step of forming a film 4 so as to cover each of the plurality of particles 3, as illustrated in Figure 3B. Here, by performing the process including the first and second steps multiple times, the layers are stacked as illustrated in Figures 3C and 3D, and as a result, structure 1 having a plurality of particles 3 at different distances from the surface of the substrate 2 can be obtained, as illustrated in Figure 1A. In one example, in the first step, the plurality of particles 3 may be formed by a sputtering method, and in the second step, a film 4 may be formed by a sputtering method so as to directly cover the surface of each individual particle 3. In other examples, at least one of the first and second steps may be carried out by a deposition method other than sputtering (e.g., CVD method, ALD method, vacuum deposition method, plasma spray method). In particular, when hydrogen storage materials are formed using physical deposition methods, it becomes possible to control the particle size of the hydrogen storage metal or hydrogen storage alloy, increase the content of particles of a desired size, improve the crystallinity of the particles, and suppress diffusion to adjacent different materials, compared to when hydrogen storage materials are synthesized in solution or by melting and subsequent rapid cooling (melt spinning method).

[0018] In one example, a process including a first step of forming multiple particles 3 by sputtering and a second step of forming a film 4 by sputtering may be repeated multiple times. Furthermore, after the substrate 2 is brought into the sputtering apparatus, the process including the first and second steps may be repeated in the sputtering apparatus without removing the substrate 2 from the sputtering apparatus. For example, after the substrate 2 is placed in one processing chamber of the sputtering apparatus, the process including the first and second steps may be repeated without removing the substrate 2 from the processing chamber. Alternatively, if the sputtering apparatus has a vacuum system including multiple processing chambers, after the substrate 2 is brought into the vacuum system of the sputtering apparatus, the process including the first and second steps may be repeated without removing the substrate 2 from the vacuum system.

[0019] In the above example, in the first step, the pressure inside the chamber is maintained in the range of 0.02 Pa to 5 Pa, a DC power in the range of 0.05 kW to 5 kW is applied to a target made of the constituent material of particles 3 containing a hydrogen-absorbing metal element, and an inert gas may be supplied to the chamber as a sputtering gas. The target includes at least one of a hydrogen-absorbing metal and a hydrogen-absorbing alloy. The target may be a pure metal or an alloy. The target includes at least one of the hydrogen-absorbing metal and hydrogen-absorbing alloy listed as the constituent material of particles 3 at the beginning of the first embodiment, for example. This can form a plurality of particles 3 that are spaced apart from each other. In the second step, the pressure inside the chamber is maintained in the range of 0.02 Pa to 5 Pa, a power in the range of 0.1 kW to 2 kW is applied to a target made of the constituent material of the film 4, and an inert gas may be supplied to the chamber.

[0020] [Examples] An example in which Cu particles are formed as particle 3 and an MgO film is formed as film 4 will be described. In this example, in order to verify the aggregation suppression effect, Cu, which is a metal that aggregates relatively easily and can be a component of hydrogen storage alloys, was selected as the constituent element of particle 3.

[0021] A Si substrate (underlay) with an SiO2 film formed on its surface by thermal oxidation was prepared, and the following first and second steps were repeated alternately 10 times each, after which a Cu film was formed in the following third step to complete structure 1. A Cu target and an MgO target were mounted in the sputtering apparatus, and the substrate was subjected to the same process, including the first and second steps, 10 times without being removed from the chamber. (1st step) In the first step, the pressure inside the chamber was maintained at 0.02 Pa, a DC power of 0.1 kW was supplied to the Cu target, and argon gas was used as the sputtering gas. (2nd process) In the second step, the pressure inside the chamber was maintained at 0.05 Pa, 1.1 kW of high-frequency power was supplied to the MgO target, and argon gas was used as the sputtering gas. (3rd step) In the third step, the pressure inside the chamber was maintained at 0.02 Pa, a DC power of 0.1 kW was supplied to the Cu target, and argon gas was used as the sputtering gas.

[0022] Figure 4A is a TEM image of the cross-section of structure 1 formed by the above embodiment, and Figure 4B is a magnified view of a part of Figure 4A. Figure 5A is a TEM image of the cross-section of structure 1' after heat treatment at 400°C for 10 hours on structure 1 formed by the above embodiment, and Figure 5B is a magnified view of a part of Figure 5A. Figure 6A is the result of EDX analysis of structure 1 in Figure 4A, and Figure 6B is the result of EDX analysis of structure 1' in Figure 5A. In Figures 6A and 6B, the horizontal axis shows the distance from the surface of structures 1 and 1', and the vertical axis shows the X-ray detection intensity. Structure 1' is a sample used to estimate the state of structure 1 after it has absorbed hydrogen and released heat.

[0023] In Figure 6A relating to structure 1, peaks representing Mg and O elements are located between the peaks representing Cu, and the positions of the peaks representing Mg and O coincide. From this, it can be seen that Cu particles and MgO films are present alternately. Furthermore, from Figure 4B relating to structure 1, it can be seen that Cu particles, whose dimensions are controlled to approximately 5 nm, are surrounded by an MgO film.

[0024] In Figure 6B, which shows structure 1' after heating structure 1, similar to Figure 6A, there are peaks representing Mg and O elements between the peaks representing Cu, and the positions of the peaks representing Mg and O coincide. From this, it can be seen that even after heating, Cu particles and MgO films are alternately present, and the Cu particles maintain their original arrangement. Furthermore, from Figure 5B of structure 1', it can be seen that even after heating, the Cu particles are surrounded by the MgO film, and the size of the Cu particles is approximately 5 nm, maintaining the size before heating. Also, from Figures 5A and 5B, it can be seen that the Cu on the outermost surface, which is not surrounded by MgO, aggregated due to heating.

[0025] [Second Embodiment] A second embodiment of the present invention will be described below with reference to Figure 7. Matters not mentioned in the second embodiment may be described in the first embodiment. In the structure 1 of the second embodiment, the inert gas 7 is present in the membrane 4 (fixed member 10). For example, the content of the inert gas 7 in the membrane 4 is, for example, 0.5 atomic percent or more. The membrane 4 may contain a plurality of microcrystals. The inert gas 7 is present, for example, at the grain boundaries of the plurality of microcrystals. By actively incorporating the inert gas into the grain boundaries of the membrane 4, it is possible to suppress the intrusion of moisture from the air into the interior of the structure 1 through the grain boundaries, which oxidizes the particles 3 and reduces the hydrogen storage capacity.

[0026] Furthermore, removing the inert gas 7 incorporated into the grain boundaries can create passages (spaces). These passages can function as pathways for hydrogen when hydrogen is absorbed into the structure 1. Therefore, the more actively the inert gas 7 is incorporated into the membrane 4 and the number of grain boundaries in the membrane 4 is increased, the easier it becomes for hydrogen to reach the interior of the structure 1, thereby improving the hydrogen absorption capacity.

[0027] For these reasons, it is preferable that the inert gas 7 incorporated into the structure 1 be removed immediately before hydrogen is absorbed into the structure 1 (particles 3). The removal of the inert gas 7 can be done, for example, by heating the structure 1.

[0028] The manufacturing method for the structure 1 of the second embodiment may include a first step of forming a plurality of particles 3, each containing a hydrogen-absorbing metal element, spaced apart from one another, and a second step of forming a film 4 so as to cover the plurality of particles 3. In particular, by adjusting the film formation conditions such as pressure and discharge voltage in the second step, it is possible to actively incorporate inert gas atoms into the grain boundaries of the film 4. Here, by performing the process including the first and second steps multiple times, a structure 1 having a plurality of particles 3 at different distances from the surface of the substrate 2 can be obtained, as illustrated in Figure 7. In one example, the plurality of particles 3 may be formed by sputtering in the first step, and the film 4 may be formed by sputtering in the second step. In other examples, at least one of the first and second steps may be carried out by a deposition method other than sputtering (e.g., CVD, ALD, vacuum deposition, plasma spray).

[0029] In one example, a process including a first step of forming multiple particles 3 by sputtering and a second step of forming a film 4 by sputtering may be repeated multiple times. Furthermore, after the substrate 2 is brought into the sputtering apparatus, the process including the first and second steps may be repeated in the sputtering apparatus without removing the substrate 2 from the sputtering apparatus. For example, after the substrate 2 is placed in one processing chamber of the sputtering apparatus, the process including the first and second steps may be repeated without removing the substrate 2 from the processing chamber. Alternatively, if the sputtering apparatus has a vacuum system including multiple processing chambers, after the substrate 2 is brought into the vacuum system of the sputtering apparatus, the process including the first and second steps may be repeated without removing the substrate 2 from the vacuum system.

[0030] In the above example, in the first step, the pressure inside the chamber is maintained within the range of 0.02 Pa to 5 Pa, a DC power in the range of 0.05 kW to 5 kW is applied to a target made of the constituent material of particles 3 containing hydrogen-absorbing metal elements, and an inert gas may be supplied to the chamber as a sputtering gas. This can form multiple particles 3 that are separated from each other. In the second step, the pressure inside the chamber cannot be uniformly specified as it varies depending on the material of the film 4, but it is desirable to have a lower pressure within the pressure range in which plasma is generated, for example, maintained within the range of 0.02 Pa to 5 Pa. This is because it is preferable for sputtering gas atoms (inert gas atoms) that collide with the target and are reflected to reach the film formation target (substrate 2) without colliding with atoms or ions before reaching the film formation target (substrate 2), that is, without losing as much energy as possible, so that they can be more easily embedded from the surface into the interior of the film 4 (fixed member 10), and the content of sputtering gas (inert gas 7) in the film 4 (fixed member 10) can be increased.

[0031] Furthermore, the voltage generated on the target made of the constituent material of film 4 (for example, the self-bias voltage in the case of high-frequency discharge) is a voltage specific to the target material used when the sputtering conditions and sputtering spatial structure are the same, and may be a voltage corresponding to energy greater than the energy required for sputtering. The greater the excess energy relative to the energy required for sputtering, the greater the incident energy of the sputtering gas atoms (inert gas atoms) reflected by the target onto the film formation target, making it easier for sputtering gas atoms (inert gas atoms) to be implanted into film 4. For example, the supplied power can be adjusted so that a self-bias voltage in the range of -100V to -500V is generated on the target made of the constituent material of film 4.

[0032] [Third Embodiment] A third embodiment of the present invention will be described below with reference to Figure 8. Matters not mentioned in the third embodiment may be based on the first or second embodiment. The structure 1 of the third embodiment has a coating film 8 that covers a membrane 4 (fixing member 10), and the coating film 8 contains an inert gas 7. The content of the inert gas 7 in the coating film 8 is, for example, 0.5 atomic percent or more. In this example, the content of the inert gas 7 in the coating film 8 is greater than the content of the inert gas 7 in the membrane 4 (fixing member 10).

[0033] The coating film 8 is a film provided for the purpose of actively incorporating the inert gas 7. Therefore, the elements constituting the coating film 8 and the film formation conditions for the coating film 8 can be set with the highest priority given to incorporating the inert gas 7 into the film. By actively incorporating the inert gas at the grain boundaries of the coating film 8, it is possible to suppress the penetration of moisture from the air into the interior of the structure 1 through the grain boundaries, which would oxidize the particles 3 and reduce the hydrogen storage capacity.

[0034] Furthermore, removing the inert gas 7 incorporated into the grain boundaries can create passages (spaces). These passages can function as pathways for hydrogen when hydrogen is absorbed into the structure 1. Therefore, the more actively the inert gas 7 is incorporated into the coating film 8 and the more the number of grain boundaries in the coating film 8 is increased, the easier it becomes for hydrogen to reach the interior of the structure 1, thereby improving the hydrogen absorption capacity. For these reasons, as in the second embodiment, it is preferable that the inert gas 7 be removed immediately before hydrogen is absorbed into the structure 1 (particles 3). The removal of the inert gas 7 can be done, for example, by heating the structure 1.

[0035] The coating film 8 is preferably made of a material containing elements with large atomic weights. In other words, the target for forming the coating film 8 is preferably made of a material containing elements with large atomic weights. This is for the following reasons: Generally, ions of the sputtering gas (i.e., inert gas 7) are accelerated on the target surface, collide with the target and knock out the atoms that make up the target, while some ions become atoms and are reflected while still retaining a certain amount of energy. Therefore, by using a target containing elements with large atomic weights, the energy held by the reflected sputtering gas atoms can be increased, making them easier to penetrate into the coating film 8. In other words, by providing the structure 1 with a coating film 8 having an atomic weight or molecular weight greater than the atomic weight or molecular weight of the film 4 (fixed member 10), the amount of sputtering gas (inert gas) incorporated into the structure 1 can be increased. As mentioned earlier, increasing the inert gas content in the structure 1 enables suppression of oxidation of particles 3 and increases the space for hydrogen to pass through, resulting in an improvement in hydrogen storage capacity.

[0036] Furthermore, for the same reasons as for film 4 (fixing member 10), the coating film 8 is composed of a high melting point material. If the coating film 8 melts and forms an alloy with particles 3 or film 4, the hydrogen storage capacity of particles 3 will decrease. Therefore, the coating film 8 needs to have enough heat resistance to prevent it from melting due to the heat generated when particles 3 absorb hydrogen. Since this heat resistance depends on the material of particles 3, the density in the structure 1 of particles 3, the hydrogen isotope gas pressure, etc., it is desirable to appropriately select the material of the coating film 8 according to the usage environment. For example, the coating film 8 may be composed of a material with a melting point of 1400°C or higher. The coating film 8 may be composed of the same material as the material constituting film 4, or it may be composed of other materials. The coating film 8 may contain multiple microcrystals, but it may also be amorphous. The coating film 8 may include, for example, at least one of an oxide (e.g., MgO, ZrO2, ZrO2·Y2O3, CaO, SiO2, and Al2O3) and at least one of a nitride (e.g., at least one of Si3N4 and AlN).

[0037] The manufacturing method for the structure 1 of the third embodiment may include a first step of forming a plurality of particles 3, each containing a hydrogen-absorbing metal element, spaced apart from one another, and a second step of forming a film 4 so as to cover the plurality of particles 3. Here, by performing the process including the first and second steps multiple times, and then performing the third step, a structure 1 having a plurality of particles 3 at different distances from the surface of the substrate 2 can be obtained, as illustrated in Figure 8. In one example, in the first step, the plurality of particles 3 may be formed by sputtering, in the second step, the film 4 may be formed by sputtering, and in the third step, the coating film 8 may be formed by sputtering. In other examples, at least one of the first, second, and third steps may be carried out by a deposition method other than sputtering (e.g., CVD, ALD, vacuum deposition, plasma spray).

[0038] In one example, the first step, followed by the second step, and then the third step, constitute one cycle, and this cycle can be repeated multiple times. In another example, the first step, followed by the second step, followed by the third step, and then the second step, constitute one cycle, and this cycle can be repeated multiple times. Furthermore, after the substrate 2 is brought into the sputtering apparatus, the process including the first, second, and third steps can be repeated in the sputtering apparatus without removing the substrate 2 from the sputtering apparatus. Alternatively, if the sputtering apparatus has a vacuum system including multiple processing chambers, after the substrate 2 is brought into the vacuum system of the sputtering apparatus, the process including the first, second, and third steps can be repeated without removing the substrate 2 from the vacuum system.

[0039] In the above example, in the first step, the pressure inside the chamber is maintained in the range of 0.02 Pa to 5 Pa, a DC power in the range of 0.05 kW to 5 kW is applied to a target made of the constituent material of particles 3 containing hydrogen-absorbing metal elements, and an inert gas may be supplied to the chamber as a sputtering gas. This can form multiple particles 3 that are separated from each other. In the second step, the pressure inside the chamber is maintained in the range of 0.02 Pa to 5 Pa, a power in the range of 0.1 kW to 2 kW is applied to a target made of the constituent material of film 4, and an inert gas may be supplied to the chamber. Furthermore, in the third step, it is desirable for the pressure inside the chamber to be low within the pressure range in which plasma is generated. This is because if the sputtering gas atoms (inert gas atoms) that collide with the target and are reflected do not collide with other atoms or ions before reaching the film formation target, that is, if they reach the film formation target without losing as much energy as possible, they are more likely to be embedded from the surface to the interior of the coating film 8, and the concentration of sputtering gas atoms (inert gas atoms) in the coating film 8 can be increased. In the third step, an inert gas is supplied to maintain the pressure inside the chamber at a range, for example, between 0.02 Pa and 5 Pa.

[0040] Furthermore, the voltage generated on the target made of the constituent materials of the coating film 8 is a voltage specific to the target material used and may be a voltage corresponding to energy greater than the energy required for sputtering. This is because the greater the excess energy relative to the energy required for sputtering, the greater the incident energy of the sputtering gas atoms (inert gas atoms) reflected by the target onto the film formation target, making it easier for the sputtering gas atoms (inert gas atoms) to be incorporated into the coating film 8. For example, the supplied power can be adjusted so that a self-bias voltage in the range of -100V to -500V is generated on the target made of the constituent materials of the coating film 8.

Claims

1. A structure in which multiple particles containing hydrogen-absorbing metal elements are arranged within a fixed member so as to be separated from each other, The surfaces of the plurality of particles are surrounded by the fixing member, The aforementioned fixing member is MgO, ZrO ２ , Y ２ O ３ CaO, Al ２ O ３ Si ３ N ４ and includes at least one AlN, The fixing member includes a base and a plurality of films placed on the surface of the base, wherein the plurality of films are laminated so that films of the same material are in contact with each other. The plurality of particles include particles placed on the surface of the substrate and particles separated from the surface of the substrate. A structure characterized by having the following structure.

2. A heat generation method for generating heat by causing hydrogen to be absorbed into the structure described in claim 1, A heat generation method characterized in that the plurality of particles are arranged in the fixed member such that they are separated from each other, thereby suppressing the aggregation of the plurality of particles, and causing the plurality of particles to absorb hydrogen and generate heat.

3. A structure in which multiple particles containing hydrogen-absorbing metal elements are arranged within a fixed member so as to be separated from each other, The surfaces of the plurality of particles are surrounded by the fixing member, The fixing member includes a base and a film disposed on the surface of the base, and the film is made of a material containing at least one of MgO, ZrO ２ , Y ２ O ３ , CaO, Al ２ O ３ and Si ３ N ４ and is composed of a material containing at least one of them. The plurality of particles include two or more particles in the film that are at different distances from the surface of the substrate. A structure characterized by having the following structure.

4. A heat generation method for generating heat by causing hydrogen to be absorbed into the structure described in claim 3, A heat generation method characterized in that the plurality of particles are arranged in the fixed member such that they are separated from each other, thereby suppressing the aggregation of the plurality of particles, and causing the plurality of particles to absorb hydrogen and generate heat.

5. A heat generation method for generating heat by causing a structure to absorb hydrogen, The aforementioned structure is A structure in which multiple particles containing hydrogen-absorbing metal elements are arranged within a fixed member so as to be separated from each other, The surfaces of the plurality of particles are surrounded by the fixing member, The fixing member comprises a base and a film disposed on the surface of the base, the film being made of a material containing at least one of MgO, ZrO₂, Y₂O₃, CaO, Al₂O₃, Si₃N₄, and AlN. The plurality of particles have a structure in which two or more particles within the film are at different distances from the surface of the substrate. A heat generation method characterized in that the plurality of particles are arranged in the fixed member such that they are separated from each other, thereby suppressing the aggregation of the plurality of particles, and causing the plurality of particles to absorb hydrogen and generate heat.

Images