JP7590378B2 - Structure and hydrogen storage structure - Google Patents

Description

The present invention relates to a structure and a hydrogen storage structure.

Hydrogen storage metals or alloys can be used as a means for storing hydrogen. Patent Document 1 describes a method for manufacturing a hydrogen storage alloy. In this manufacturing method, an rf arc plasma is formed in a vacuum vessel at a reduced pressure, and Ti and Cu, or Ti, Cu and Si vapors are reacted in the plasma to form and recover fine powder of a Ti-Cu alloy or Ti-Cu-Si alloy. According to Patent Document 1, the fine powder produced by this manufacturing method has a large surface area, and therefore can store hydrogen in an amount 10 to 50 times greater than conventional methods.

Japanese Unexamined Patent Publication No. 61-270301

Particles containing hydrogen-storing metal elements, such as hydrogen-storing metals and hydrogen-storing alloys, can generate heat when they absorb hydrogen. In particular, by reducing the size of the particles in order to increase the surface area of the particles per unit volume, the hydrogen absorption efficiency can be improved and the amount of heat generated when hydrogen is absorbed can also be increased. If the amount of heat generated increases, the particles can aggregate. Alternatively, the particles can aggregate when heat is applied to them from the outside. If the particles aggregate, the hydrogen absorption capacity can be reduced.

The present invention aims to suppress the aggregation of multiple particles containing hydrogen-storing metal elements.

A first aspect of the present invention relates to a heat generation method for causing a structure to absorb hydrogen and generate heat, the structure having a structure in which a plurality of particles each containing a hydrogen-absorbing metal element are arranged in a fixing member so as to be spaced apart from one another, the entire surface of each of the plurality of particles is surrounded by the fixing member, the fixing member includes at least one of an oxide and a nitride, the fixing member includes a base and a film arranged on the surface of the base, the plurality of particles include two or more particles arranged on the surface of the base and at different distances from the surface of the base, and the film is in contact with the entire surface of each of the plurality of particles, and the plurality of particles are arranged in the fixing member so as to be spaced apart from one another, thereby suppressing agglomeration of the plurality of particles, and the plurality of particles are caused to absorb hydrogen, thereby generating heat.
A second aspect of the present invention relates to a structure in which a plurality of particles each containing a hydrogen-storing metal element are arranged in a fixing member so as to be spaced apart from one another, the entire surface of each of the plurality of particles being surrounded by the fixing member, the fixing member comprising at least one of an oxide and a nitride, the fixing member comprising a base and a film arranged on the surface of the base, the plurality of particles including two or more particles arranged on the surface of the base and at different distances from the surface of the base, and the film configured so that the distance between the plurality of particles is in the range of 1 nm or more and 10 nm or less.
A third aspect of the present invention relates to a heat generation method for generating heat by absorbing hydrogen in a structure, the structure having a structure in which a plurality of particles each containing a hydrogen absorbing metal element are arranged in a fixing member so as to be spaced apart from one another, the entire surface of each of the plurality of particles is surrounded by the fixing member, the fixing member includes at least one of an oxide and a nitride, the fixing member includes a base and a film arranged on the surface of the base, the plurality of particles include two or more particles arranged on the surface of the base and at different distances from the surface of the base, and the plurality of particles are spaced apart from one another even after being subjected to a heat treatment at 400°C for 10 hours, and the plurality of particles are arranged in the fixing member so as to be spaced apart from one another, thereby suppressing agglomeration of the plurality of particles, and the plurality of particles are caused to absorb hydrogen, thereby generating heat.
A fourth aspect of the present invention relates to a hydrogen storage structure in which a plurality of particles, each containing a hydrogen storage metal element, are arranged in a fixing member so as to be spaced apart from one another, the entire surface of each of the plurality of particles being surrounded by the fixing member, the fixing member comprising at least one of an oxide and a nitride, the fixing member comprising a base and a film arranged on a surface of the base, the film comprising a plurality of microcrystals, and each of the plurality of particles being in contact with at least one of the plurality of microcrystals of the film.
A fifth aspect of the present invention relates to a heat generation method for generating heat by absorbing hydrogen in a structure according to the second aspect, in which the particles are arranged in the fixing member so as to be spaced apart from one another, thereby suppressing agglomeration of the particles, and the particles are caused to absorb hydrogen, thereby causing the particles to generate heat.
A sixth aspect of the present invention relates to a heat generation method for generating heat by absorbing hydrogen in a hydrogen storage structure according to the fourth aspect, in which the particles are arranged in the fixing member so as to be spaced apart from one another, thereby suppressing agglomeration of the particles, and the particles are caused to absorb hydrogen, thereby causing the particles to generate heat.

According to the present invention, aggregation of multiple particles containing hydrogen-storing metal elements is suppressed.

1 is a schematic cross-sectional view of a structure according to a first embodiment of the present invention. 1 is a schematic cross-sectional view of a structure according to a first embodiment of the present invention. 3A to 3C are diagrams illustrating a method for manufacturing the structure according to the first embodiment of the present invention. 3A to 3C are diagrams illustrating a method for manufacturing the structure according to the first embodiment of the present invention. 3A to 3C are diagrams illustrating a method for manufacturing the structure according to the first embodiment of the present invention. 3A to 3C are diagrams illustrating a method for manufacturing the structure according to the first embodiment of the present invention. 4 is a TEM image of a cross section of a structure according to an embodiment. 4B is a TEM image of a cross section of a structure according to an embodiment (enlarged view of FIG. 4A ). TEM image of a cross section of the structure after heat treatment. TEM image of a cross section of the structure after heat treatment (enlarged view of FIG. 5A). FIG. 4B shows the results of EDX analysis of the structure of FIG. 4A. FIG. 5B shows the results of EDX analysis of the structure of FIG. 5A. FIG. 5 is a schematic cross-sectional view of a structure according to a second embodiment of the present invention. FIG. 13 is a schematic cross-sectional view of a structure according to a third embodiment of the present invention.

The present invention will now be described through exemplary embodiments with reference to the accompanying drawings.

[First embodiment]
1 and 2 show schematic cross-sectional views of a structure 1 according to a first embodiment of the present invention. Here, Fig. 2 corresponds to an enlarged view of a portion of the cross-section taken along line AA' in 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 spaced apart from one another.

The fixing member 10 functions to keep the multiple particles 3 separated from each other even in a high-temperature environment, for example, to fix the positions of the multiple particles 3. Each of the multiple particles 3 contains a hydrogen-storing 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 multiple particles 3 is surrounded by the fixing member 10.

The particles 3 are particles made of a material containing a hydrogen storage metal element, and may include, for example, at least one of a hydrogen storage metal particle and a hydrogen storage alloy particle. The hydrogen storage 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 storage 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 size of each of the multiple particles 3 may be, for example, 2 nm or more and 1000 nm or less. From the viewpoint of increasing the total surface area of the multiple particles 3, the size of each of the multiple particles 3 is 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 either single crystalline or polycrystalline.

The film 4 may be made of a high melting point material, for example, a material having a melting point of 1400° C. or higher. The film 4 may include a plurality of microcrystals, but may also be amorphous. The film 4 may include, for example, at least one of an oxide (e.g., at least one of MgO, ZrO ₂ , ZrO _{2.Y 2} O ₃ , CaO, SiO ₂ and Al ₂ O ₃ ) and a nitride (e.g., at least one of Si ₃ N ₄ and AlN).

The base 2 may be, for example, a Si substrate or a substrate in which a SiO ₂ film is formed on a Si substrate, but may be made of other materials (for example, metals or insulators). The base 2 is preferably made of a material having a melting point of, for example, 1400° C. or higher. The base 2 may be a member such as a film made of the same material as the film 4, or may be a member such as a film made of a material different from that of the film 4. The base 2 may be a free-standing member, or may be a member supported by another member.

If the high melting point film 4 is not present to separate the particles 3 from each other, when the particles 3 absorb hydrogen and generate heat, the heat may cause two or more particles 3 located nearby to aggregate. This may increase the size of each particle, which may reduce the hydrogen absorption capacity. The presence of the high melting point film 4 to separate the particles 3 from each other suppresses the aggregation of two or more particles 3 located nearby due to the heat generated when the particles 3 absorb hydrogen. The presence of the high melting point film 4 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 the particles 3 absorb hydrogen. The heat resistance required for the film 4 is such that it does not melt when the structure 1 generates heat. The temperature when the structure 1 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 cannot be uniformly specified. Therefore, it is desirable to select the material of the film 4 appropriately depending on the usage environment, but it is, for example, a material having 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. If the distance between the multiple separated particles 3 increases, the content of the hydrogen storage metal or hydrogen storage alloy in the structure 1 decreases, which is undesirable.

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

The method for manufacturing the structure 1 may include a first step of forming a plurality of particles 3 each containing a hydrogen storage metal element so as to be separated from one another and arranging the individual particles 3 in an island shape, as illustrated in FIG. 3A, and a second step of forming a film 4 so as to cover each of the plurality of particles 3, as illustrated in FIG. 3B. Here, by carrying out the treatment including the first step and the second step multiple times, the particles are stacked as illustrated in FIG. 3C and FIG. 3D, and as a result, as illustrated in FIG. 1A, a structure 1 having a plurality of particles 3 at different distances from the surface of the base 2 can be obtained. In one example, in the first step, a plurality of particles 3 are formed by a sputtering method, and in the second step, a film 4 can be formed by a sputtering method so as to directly cover the surface of each particle 3. In another example, at least one of the first step and the second step may be carried out by a deposition method other than the sputtering method (e.g., a CVD method, an ALD method, a vacuum deposition method, a plasma spray method). In particular, when the above-mentioned hydrogen storage material is formed using a physical deposition method, it is possible to control the particle size of the hydrogen storage metal or alloy, increase the content of particles of the desired size, increase the crystallinity of the particles, and suppress diffusion into adjacent different materials, compared to when the hydrogen storage material is synthesized in a solution or synthesized by melting and then rapidly cooling (melt spinning method).

In one example, a process including a first step of forming a plurality of particles 3 by a sputtering method and a second step of forming a film 4 by a sputtering method can be repeated multiple times. In addition, after the base 2 is carried into a sputtering device, the process including the first step and the second step can be repeated in the sputtering device without carrying the base 2 out of the sputtering device. For example, after the base 2 is placed in one processing chamber of the sputtering device, the process including the first step and the second step can be repeated without removing the base 2 from the processing chamber. Alternatively, when the sputtering device has a vacuum system including multiple processing chambers, after the base 2 is carried into the vacuum system of the sputtering device, the process including the first step and the second step can be repeated without removing the base 2 from the vacuum system.

In the above example, in the first step, the pressure in the chamber is maintained within a range of 0.02 Pa to 5 Pa, a direct current power within a range of 0.05 kW to 5 kW is applied to the target made of the constituent material of the particle 3 containing the hydrogen storage metal element, and an inert gas can be supplied to the chamber as a sputtering gas. The target includes at least one of a hydrogen storage metal and a hydrogen storage alloy. The target may be a pure metal or an alloy. The target includes at least one of the hydrogen storage metal and the hydrogen storage alloy listed as the material constituting the particle 3 at the beginning of the first embodiment, for example. This allows a plurality of particles 3 located at a distance from each other to be formed. In the second step, the pressure in the chamber is maintained within a range of 0.02 Pa to 5 Pa, a power within a range of 0.1 kW to 2 kW is applied to the target made of the constituent material of the film 4, and an inert gas can be supplied to the chamber.

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

A Si substrate (base) having a _SiO2 film formed on its surface by thermal oxidation was prepared, and the following first and second steps were alternately repeated 10 times each, and then a Cu film was formed in the following third step to complete the structure 1. A Cu target and an MgO target were attached to the sputtering device, and the treatment including the first and second steps was repeated 10 times on the base without removing it from the chamber.
(First step)
In the first step, the pressure inside the chamber was maintained at 0.02 Pa, a direct current power of 0.1 kW was supplied to the Cu target, and argon gas was used as the sputtering gas.
(Second step)
In the second step, the pressure inside the chamber was maintained at 0.05 Pa, a high-frequency power of 1.1 kW was supplied to the MgO target, and argon gas was used as the sputtering gas.
(Third process)
In the third step, the pressure inside the chamber was maintained at 0.02 Pa, a direct current power of 0.1 kW was supplied to the Cu target, and argon gas was used as the sputtering gas.

Figure 4A is a TEM image of a cross section of the structure 1 formed by the above embodiment, and Figure 4B is an enlarged view of a portion of Figure 4A. Figure 5A is a TEM image of a cross section of the structure 1' after heat treatment at 400°C for 10 hours on the structure 1 formed by the above embodiment, and Figure 5B is an enlarged view of a portion of Figure 5A. Figure 6A is the result of EDX analysis of the structure 1 in Figure 4A, and Figure 6B is the result of EDX analysis of the structure 1' in Figure 5A. In Figures 6A and 6B, the horizontal axis indicates the distance from the surface of the structures 1 and 1', and the vertical axis indicates the detected intensity of X-rays. Note that the structure 1' is a sample for estimating the state of the structure 1 after absorbing hydrogen and generating heat.

In FIG. 6A for structure 1, between the peaks representing Cu elements, there are peaks representing Mg elements and O elements, and the position of the peak representing Mg element coincides with the position of the peak representing O element. This shows that Cu particles and MgO film exist alternately. Also, from FIG. 4B for structure 1, it can be seen that Cu particles with dimensions controlled to about 5 nm are surrounded by MgO film.

In FIG. 6B showing structure 1' after heating structure 1, similar to FIG. 6A, there are peaks showing Mg and O elements between the peaks showing Cu elements, and the position of the peak showing Mg element coincides with the position of the peak showing O element. This shows that even after heating, Cu particles and MgO film are present alternately, and the Cu particles maintain their original arrangement. Also, from FIG. 5B showing structure 1', it can be seen that even after heating, the Cu particles are surrounded by the MgO film, and the dimensions of the Cu particles are about 5 nm, maintaining the dimensions before heating. Also, from FIG. 5A and FIG. 5B, it can be seen that the Cu on the outermost surface that is not surrounded by MgO has aggregated due to heating.

[Second embodiment]
Hereinafter, the second embodiment of the present invention will be described with reference to FIG. 7. It should be noted that matters not mentioned as the second embodiment may follow the first embodiment. In the structure 1 of the second embodiment, the inert gas 7 is present in the film 4 (fixing member 10). For example, the content of the inert gas 7 in the film 4 is, for example, 0.5 atomic % or more. The film 4 may contain a plurality of microcrystals. The inert gas 7 is present, for example, in the grain boundaries of the plurality of microcrystals. By actively incorporating the inert gas into the grain boundaries of the film 4, it is possible to suppress the moisture in the air from penetrating the inside of the structure 1 through the grain boundaries and oxidizing the particles 3, thereby reducing the hydrogen storage capacity.

In addition, by removing the inert gas 7 that has been absorbed into the grain boundaries, passages (spaces) can be generated. These passages can function as paths for hydrogen when hydrogen is absorbed into the structure 1. Therefore, the more inert gas 7 is actively absorbed into the film 4 and the more the number of grain boundaries in the film 4 is increased, the easier it becomes for hydrogen to reach the inside of the structure 1, improving the hydrogen absorption capacity.

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

The method for manufacturing the structure 1 of the second embodiment may include a first step of forming a plurality of particles 3 each containing a hydrogen storage metal element so as to be separated from each other, 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 the 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 step and the second step multiple times, it is possible to obtain a structure 1 having a plurality of particles 3 with different distances from the surface of the base 2, as illustrated in FIG. 7. In one example, the plurality of particles 3 may be formed by a sputtering method in the first step, and the film 4 may be formed by a sputtering method in the second step. In another example, at least one of the first step and the second step may be performed by a deposition method other than the sputtering method (e.g., a CVD method, an ALD method, a vacuum deposition method, a plasma spray method).

In one example, a process including a first step of forming a plurality of particles 3 by a sputtering method and a second step of forming a film 4 by a sputtering method can be repeated multiple times. In addition, after the base 2 is carried into a sputtering device, the process including the first step and the second step can be repeated in the sputtering device without carrying the base 2 out of the sputtering device. For example, after the base 2 is placed in one processing chamber of the sputtering device, the process including the first step and the second step can be repeated without removing the base 2 from the processing chamber. Alternatively, when the sputtering device has a vacuum system including multiple processing chambers, after the base 2 is carried into the vacuum system of the sputtering device, the process including the first step and the second step can be repeated without removing the base 2 from the vacuum system.

In the above example, in the first step, the pressure in the chamber is maintained within a range of 0.02 Pa to 5 Pa, a direct current power within a range of 0.05 kW to 5 kW is applied to the target made of the constituent material of the particles 3 containing the hydrogen-storing metal element, and an inert gas can be supplied to the chamber as a sputtering gas. This can form a plurality of particles 3 separated from each other. In the second step, the pressure in the chamber cannot be uniformly determined because it varies depending on the material of the film 4, but it is preferable that it is low within the pressure range in which plasma is generated, and is maintained at a pressure within a range of, for example, 0.02 Pa to 5 Pa. This is because the sputtering gas atoms (inert gas atoms) that collide with the target and are reflected without colliding with atoms or ions before reaching the film formation target (base 2), that is, without losing as much energy as possible, are more likely to be driven into the film 4 (fixing member 10) from the surface, and the content of the sputtering gas (inert gas 7) in the film 4 (fixing member 10) can be increased.

In addition, 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 can be a voltage equivalent to energy equal to or 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 the sputtering gas atoms (inert gas atoms) to be implanted into film 4. For example, the supply 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.

[Third embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIG. 8. Note that matters not mentioned as the third embodiment may follow the first or second embodiment. The structure 1 of the third embodiment has a coating film 8 so as to cover the film 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 % 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 film 4 (fixing member 10).

The coating film 8 is a film that is provided for the purpose of actively incorporating the inert gas 7. Therefore, the elements that compose 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 into the grain boundaries of the coating film 8, it is possible to prevent moisture in the air from penetrating the inside of the structure 1 through the grain boundaries and oxidizing the particles 3, thereby reducing the hydrogen storage capacity.

In addition, by removing the inert gas 7 that has been absorbed into the grain boundaries, a passage (space) can be generated. This passage can function as a path for hydrogen when hydrogen is absorbed into the structure 1. Therefore, the more the inert gas 7 is actively absorbed 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 inside of the structure 1, and the hydrogen absorption capacity can be improved. For these reasons, as in the second embodiment, it is preferable that the inert gas 7 is removed immediately before hydrogen is absorbed into the structure 1 (particles 3). The inert gas 7 can be removed, for example, by heating the structure 1.

The coating film 8 is preferably made of a material containing an element with a large atomic weight. In other words, the target for forming the coating film 8 is preferably made of a material containing an element with a large atomic weight. This is for the following reasons. In general, ions of the sputtering gas (i.e., the inert gas 7) are accelerated on the target surface, collide with the target and eject the atoms that make up the target, while some of the ions become atoms and are reflected while still retaining a certain amount of energy. Therefore, by using a target containing an element with a large atomic weight, the energy held by the reflected sputtering gas atoms can be increased, making it easier to be driven 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 larger than the atomic weight or molecular weight of the film 4 (fixing member 10), the amount of sputtering gas (inert gas) taken into the structure 1 can be increased. As described above, an increase in the content of the inert gas in the structure 1 makes it possible to suppress the oxidation of the particles 3 and increase the space for passing hydrogen, resulting in an improvement in the hydrogen storage capacity.

For the same reason as the film 4 (fixing member 10), the coating film 8 is made of a high melting point material. If the coating film 8 melts and forms an alloy with the particles 3 or the film 4, the hydrogen storage capacity of the particles 3 will decrease, so the coating film 8 needs to have heat resistance to the extent that it does not melt due to the heat generated by the particles 3 absorbing hydrogen. This heat resistance depends on the material of the particles 3, the density of the particle 3 in the structure 1, the hydrogen isotope gas pressure, etc., so it is desirable to select the material of the coating film 8 appropriately depending on the usage environment. The coating film 8 can be made of a material with a melting point of 1400°C or more, for example. The coating film 8 can be made of the same material as the material constituting the film 4, or can be made of another material. The coating film 8 can include a plurality of microcrystals, but can also be amorphous. The coating film 8 may _{include, for example, at least one of an oxide (e.g., at least one of MgO, ZrO2, ZrO2.Y2O3 , CaO} , _SiO2 , and _Al2O3 ) and a nitride (e.g., at least _one of _{Si3N4 and AlN} ).

The method for manufacturing the structure 1 of the third embodiment may include a first step of forming a plurality of particles 3 each containing a hydrogen-storing metal element so as to be separated from one another, and a second step of forming a film 4 so as to cover the plurality of particles 3. Here, by carrying out a process including the first step and the second step multiple times and then carrying out the third step, it is possible to obtain a structure 1 having a plurality of particles 3 at different distances from the surface of the base 2, as illustrated in FIG. 8. In one example, the plurality of particles 3 may be formed by a sputtering method in the first step, the film 4 may be formed by a sputtering method in the second step, and the coating film 8 may be formed by a sputtering method in the third step. In another example, at least one of the first step, the second step, and the third step may be carried out by a deposition method other than the sputtering method (e.g., a CVD method, an ALD method, a vacuum deposition method, a plasma spray method).

In one example, the first step, the second step, and the third step are considered as one cycle, and this cycle can be repeated multiple times. In another example, the first step, the second step, the third step, and the second step are considered as one cycle, and this cycle can be repeated multiple times. Also, after the base 2 is carried into the sputtering apparatus, the process including the first step, the second step, and the third step can be repeated in the sputtering apparatus without carrying the base 2 out of the sputtering apparatus. Alternatively, when the sputtering apparatus has a vacuum system including multiple processing chambers, after the base 2 is carried into the vacuum system of the sputtering apparatus, the process including the first step, the second step, and the third step can be repeated without taking the base 2 out of the vacuum system.

In the above example, in the first step, the pressure in the chamber is maintained within a range of 0.02 Pa to 5 Pa, a direct current power within a range of 0.05 kW to 5 kW is applied to a target made of a constituent material of the particles 3 containing a hydrogen-storing metal element, and an inert gas is supplied to the chamber as a sputtering gas. This allows a plurality of particles 3 separated from one another to be formed. In the second step, the pressure in the chamber is maintained within a range of 0.02 Pa to 5 Pa, a power within a range of 0.1 kW to 2 kW is applied to a target made of a constituent material of the film 4, and an inert gas is supplied to the chamber. In the third step, the pressure in the chamber is desirably low within the pressure range at which plasma is generated. This is because the sputtering gas atoms (inert gas atoms) that collide with the target and are reflected can be more easily driven into the coating film 8 from its surface if they reach the film formation target without colliding with other atoms or ions, that is, without losing as much energy as possible, and the concentration of the sputtering gas atoms (inert gas atoms) in the coating film 8 can be increased. In the third step, the inert gas is supplied so that the pressure in the chamber is maintained within a range of, for example, 0.02 Pa to 5 Pa.

The voltage generated at the target made of the material that constitutes the coating film 8 is a voltage specific to the target material used, and can be a voltage equivalent to energy equal to or 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 supply power can be adjusted so that a self-bias voltage in the range of -100V to -500V is generated at the target made of the material that constitutes the coating film 8.

Claims (6)

A heat generation method for generating heat by absorbing hydrogen in a structure, comprising the steps of:
The structure comprises:
A plurality of particles each including a hydrogen storage metal element are disposed in a fixing member so as to be spaced apart from one another;
the entire surface of each of the plurality of particles is surrounded by the fixing member;
the fixing member includes at least one of an oxide and a nitride;
The fixing member includes a substrate and a film disposed on a surface of the substrate;
the plurality of particles include two or more particles disposed on the surface of the substrate at different distances from the surface of the substrate;
the film contacts the entire surface of each of the plurality of particles;
It has the following structure:
the plurality of particles are arranged in the fixing member so as to be spaced apart from one another, thereby suppressing aggregation of the plurality of particles, and the plurality of particles are caused to occlude hydrogen, thereby causing the plurality of particles to generate heat;
A method for generating heat. A structure in which a plurality of particles each containing a hydrogen storage metal element are arranged in a fixing member so as to be spaced apart from each other,
the entire surface of each of the plurality of particles is surrounded by the fixing member;
the fixing member includes at least one of an oxide and a nitride;
The fixing member includes a substrate and a film disposed on a surface of the substrate;
the plurality of particles include two or more particles disposed on the surface of the substrate at different distances from the surface of the substrate;
The film is configured such that the distance between the particles is in the range of 1 nm or more and 10 nm or less.
A structure characterized by having the following structure. A heat generation method for generating heat by absorbing hydrogen in a structure, comprising the steps of:
The structure comprises:
A plurality of particles each including a hydrogen storage metal element are disposed in a fixing member so as to be spaced apart from one another;
the entire surface of each of the plurality of particles is surrounded by the fixing member;
the fixing member includes at least one of an oxide and a nitride;
The fixing member includes a substrate and a film disposed on a surface of the substrate;
the plurality of particles include two or more particles disposed on the surface of the substrate at different distances from the surface of the substrate;
The particles are separated from each other even after being subjected to a heat treatment at 400° C. for 10 hours.
It has the following structure:
the plurality of particles are arranged in the fixing member so as to be spaced apart from one another, thereby suppressing aggregation of the plurality of particles, and the plurality of particles are caused to occlude hydrogen, thereby causing the plurality of particles to generate heat;
A method for generating heat. A hydrogen storage structure comprising a plurality of particles each including a hydrogen storage metal element, the particles being disposed in a fixing member so as to be spaced apart from one another,
the entire surface of each of the plurality of particles is surrounded by the fixing member;
the fixing member includes at least one of an oxide and a nitride;
The fixing member includes a substrate and a film disposed on a surface of the substrate;
the film includes a plurality of crystallites, and each of the plurality of particles is in contact with at least one of the plurality of crystallites of the film;
The hydrogen storage structure has the following structure: A method for generating heat by absorbing hydrogen in the structure according to claim 2, comprising the steps of :
A heat generating method comprising: arranging the plurality of particles in the fixing member so that the particles are spaced apart from one another, thereby suppressing agglomeration of the plurality of particles; and causing the plurality of particles to absorb hydrogen, thereby generating heat from the plurality of particles. A method for generating heat by absorbing hydrogen in the hydrogen storage structure according to claim 4 , comprising the steps of:
A heat generating method comprising: arranging the plurality of particles in the fixing member so that the particles are spaced apart from one another, thereby suppressing agglomeration of the plurality of particles; and causing the plurality of particles to absorb hydrogen, thereby generating heat from the plurality of particles.

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