Hydrogen filling method, hydrogen filling apparatus, sample analysis method, and sample analysis apparatus

Abstract

The present invention provides a hydrogen filling method and apparatus that are highly safe, low-cost, and capable of filling a sample with hydrogen under atmospheric pressure. [Solution] A method for filling a sample 1 made of metal with hydrogen, comprising: (a) a step of converting water vapor into a low-temperature plasma under atmospheric pressure; and (b) a step of bringing the low-temperature plasma-converted water vapor into contact with the surface 1a of the sample 1 under atmospheric pressure.

Description

Technical Field

[0001] The present invention relates to a hydrogen filling method, a hydrogen filling device, a sample analysis method, and a sample analysis device.

Background Art

[0002] In the development of high-strength steel, hydrogen embrittlement in which strength and toughness deteriorate due to hydrogen is a major problem. However, the material tissue changes related to hydrogen embrittlement have not been clarified, and in order to elucidate the mechanism of hydrogen embrittlement, it is desirable to perform observations over time while introducing hydrogen into the steel.

[0003] For example, Patent Document 1 discloses a method of filling hydrogen by exposing a test piece in high-pressure hydrogen gas. Further, Patent Document 2 discloses a method of immersing a steel material in an electrolytic solution and filling hydrogen electrochemically. Furthermore, Patent Document 3 discloses a sample analysis method capable of analyzing the sample surface with high resolution and over time while introducing hydrogen into the sample using an electron beam device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the method described in Patent Document 1 uses high-pressure hydrogen gas, which poses an explosion risk. Therefore, it requires large-scale equipment such as pressure vessels, gas compressors, and explosion-proof infrastructure, resulting in significant costs. Furthermore, microscopes are typically structurally unsuitable for use in high-pressure hydrogen gas.

[0006] Furthermore, although the method described in Patent Document 2 allows for efficient filling with hydrogen, hydrogen bubbles are generated on the surface of the sample in the electrolyte, which may interfere with in-situ observation using a microscope.

[0007] The method described in Patent Document 3 allows for high-resolution and time-series analysis of the sample surface by performing observation using an electron microscope or the like. On the other hand, the time resolution when clearly observing the sample surface using an electron microscope is only a few seconds, so the development of other complementary methods is required when performing in-situ observation with higher time resolution.

[0008] As a result of our investigations, we conceived the idea that optical microscopes, laser microscopes, etc., are suitable for in-situ observation with high temporal resolution, and that in order to install them, it is necessary to develop a method for filling them with hydrogen under atmospheric pressure.

[0009] The present invention aims to solve the above problems and provide a hydrogen filling method and apparatus that are highly safe, low-cost, and capable of filling a sample with hydrogen under atmospheric pressure, as well as a sample analysis method and apparatus that can analyze the sample surface over time with high temporal resolution under atmospheric pressure while filling the sample with hydrogen. [Means for solving the problem]

[0010] This invention was made to solve the above problems, and its gist is the following hydrogen filling method, hydrogen filling apparatus, sample analysis method, and sample analysis apparatus.

[0011] (1) A method for filling a sample made of metal with hydrogen, (a) A process of converting water vapor into a low-temperature plasma under atmospheric pressure, (b) The step of bringing the low-temperature plasma-converted water vapor into contact with the surface of the sample under atmospheric pressure, Hydrogen refueling method.

[0012] (2) In step (a) above, the water vapor is converted into a low-temperature plasma under atmospheric pressure by generating a dielectric barrier discharge in the gas containing the water vapor. The hydrogen filling method described in (1) above.

[0013] (3) In step (a) above, an alternating voltage is applied between the electrode and the sample, and the electrode and the sample are electrically connected via a dielectric and a gas containing water vapor to generate a dielectric barrier discharge. The hydrogen filling method described in (2) above.

[0014] (4) In step (a) above, an alternating voltage is applied between the pair of electrodes, and the pair of electrodes are electrically connected via a dielectric and a gas containing water vapor to generate a dielectric barrier discharge. The hydrogen filling method described in (2) above.

[0015] (5) In step (a) above, the predetermined gas is made into a low-temperature plasma by generating a dielectric barrier discharge in a predetermined gas that can be made into a low-temperature plasma, and the water vapor is made into a low-temperature plasma at atmospheric pressure by supplying the water vapor-containing gas into the predetermined gas that has been made into a low-temperature plasma. The hydrogen filling method described in (1) above.

[0016] (6) In step (a) above, an AC voltage is applied between the electrode and the sample, and the electrode and the sample are electrically connected via a dielectric and the predetermined gas to generate a dielectric barrier discharge. The hydrogen filling method described in (5) above.

[0017] (7) In the step (a), an alternating voltage is applied between a pair of electrodes, and the pair of electrodes are electrically connected through a dielectric and the predetermined gas, thereby generating dielectric barrier discharge. The hydrogen filling method according to (5) above.

[0018] (8) In the step (b), the surface temperature is controlled to a predetermined temperature, and the low-temperature plasmaized water vapor is brought into contact with the surface under atmospheric pressure. The hydrogen filling method according to any one of (1) to (7) above.

[0019] (9) An apparatus for filling hydrogen into a sample made of metal, comprising: a plasma generation unit that generates low-temperature plasma of water vapor under atmospheric pressure; and a gas supply unit that supplies the water vapor so that the low-temperature plasmaized water vapor contacts the surface of the sample under atmospheric pressure. Hydrogen filling apparatus.

[0020] (10) The plasma generation unit generates low-temperature plasma of the water vapor under atmospheric pressure by generating dielectric barrier discharge in the gas containing the water vapor. The hydrogen filling apparatus according to (9) above.

[0021] (11) The plasma generation unit includes an electrode and a dielectric, an alternating voltage is applied between the electrode and the sample, and the electrode and the sample are electrically connected through the dielectric and the gas containing the water vapor, thereby generating dielectric barrier discharge. The hydrogen filling apparatus according to (10) above.

[0022] (12) The plasma generation unit includes a pair of electrodes and a dielectric, an alternating voltage is applied between the pair of electrodes, and the pair of electrodes are electrically connected through the dielectric and the gas containing the water vapor, thereby generating dielectric barrier discharge. The hydrogen filling apparatus according to (10) above.

[0023] (13) The plasma generating unit generates a dielectric barrier discharge in a predetermined gas that can be turned into a low-temperature plasma, thereby turning the predetermined gas into a low-temperature plasma, and supplies the water vapor-containing gas into the predetermined gas that has been turned into a low-temperature plasma, thereby turning the water vapor into a low-temperature plasma at atmospheric pressure. The hydrogen filling device described in (9) above.

[0024] (14) The plasma generating unit includes an electrode and a dielectric, By applying an AC voltage between the electrode and the sample, and electrically connecting the electrode and the sample via the dielectric and the predetermined gas, a dielectric barrier discharge is generated. The hydrogen refueling device described in (13) above.

[0025] (15) The plasma generating unit includes a pair of electrodes and a dielectric, By applying an AC voltage between the pair of electrodes and electrically connecting the pair of electrodes via the dielectric and the predetermined gas, a dielectric barrier discharge is generated. The hydrogen refueling device described in (13) above.

[0026] (16) The system further comprises a temperature control unit that controls the temperature of the surface to reach a predetermined temperature, The gas supply unit supplies water vapor such that the low-temperature plasma-formed water vapor comes into contact with the surface under atmospheric pressure while the surface temperature is controlled to a predetermined temperature. A hydrogen refueling device as described in any of (9) through (15) above.

[0027] (17) A method for analyzing a sample made of metal, The process described in any of (1) to (7) above, (a) and (b), (c) The process includes analyzing the surface in contact with the low-temperature plasma-formed water vapor under atmospheric pressure, Sample analysis method.

[0028] (18) A method for analyzing a sample made of metal, The steps described in (a) and (b) above in (8), (c) The process includes analyzing the surface in contact with the low-temperature plasma-formed water vapor under atmospheric pressure, Sample analysis method.

[0029] (19) An analytical apparatus for a sample made of metal, The plasma generating unit and the gas supply unit described in any of (9) to (15) above, (c) The system comprises an analysis unit that analyzes the surface in which the low-temperature plasma-formed water vapor has come into contact with the surface under atmospheric pressure, Sample analysis device.

[0030] (20) An analytical apparatus for a sample made of metal, The plasma generating unit and the gas supply unit described in (16) above, (c) The system comprises an analysis unit that analyzes the surface in which the low-temperature plasma-formed water vapor has come into contact with the surface under atmospheric pressure, Sample analysis device. [Effects of the Invention]

[0031] According to the present invention, it is possible to fill a sample with hydrogen under atmospheric pressure, which is highly safe and low-cost, and furthermore, to analyze the sample surface over time with high temporal resolution under atmospheric pressure while filling the sample with hydrogen. [Brief explanation of the drawing]

[0032] [Figure 1] This figure shows a schematic configuration of a hydrogen refueling apparatus according to one embodiment of the present invention. [Figure 2] This figure shows a schematic configuration of a hydrogen filling apparatus according to another embodiment of the present invention. [Figure 3] This figure shows a schematic configuration of a hydrogen filling apparatus according to another embodiment of the present invention. [Figure 4]This figure shows a schematic configuration of a hydrogen filling apparatus according to another embodiment of the present invention. [Figure 5] This figure shows a schematic configuration of a hydrogen filling apparatus according to another embodiment of the present invention. [Figure 6] This figure shows a schematic configuration of a hydrogen filling apparatus according to another embodiment of the present invention. [Figure 7] This figure shows a schematic configuration of a hydrogen filling apparatus according to another embodiment of the present invention. [Figure 8] This figure shows a schematic configuration of a sample analysis device according to one embodiment of the present invention. [Figure 9] This is a diagram illustrating the dimensions and shape of the test specimen. [Figure 10] This is a diagram illustrating the dimensions and shape of a wedge. [Modes for carrying out the invention]

[0033] A hydrogen filling method, hydrogen filling apparatus, sample analysis method, and sample analysis apparatus according to embodiments of the present invention will be described with reference to Figures 1 to 8.

[0034] Figure 1 is a diagram showing the schematic configuration of a hydrogen filling apparatus 100 according to one embodiment of the present invention. The hydrogen filling apparatus 100 is an apparatus for filling a sample 1 made of metal with hydrogen, and comprises a plasma generation unit 11 and a gas supply unit 12.

[0035] The plasma generation unit 11 converts water vapor into a low-temperature plasma under atmospheric pressure. In the configuration shown in Figure 1, the plasma generation unit 11 includes an electrode 11a made of a copper plate and a dielectric 11c made of a glass plate. The dielectric 11c is provided on the electrode 11a side between the electrode 11a and the sample 1. An AC voltage is then applied between the sample 1 and the electrode 11a using an AC power supply 11e.

[0036] In this process, a gas containing water vapor (hereinafter referred to as "water vapor-containing gas") is supplied between the sample 1 and the dielectric 11c by the gas supply unit 12, which will be described later. As a result, the electrode 11a and the sample 1 are electrically connected (discharge) via the dielectric 11c and the water vapor-containing gas. Consequently, a dielectric barrier discharge occurs in the water vapor-containing gas between the sample 1 and the dielectric 11c, and the water vapor is converted into a low-temperature plasma under atmospheric pressure. At this time, hydrogen atoms and / or hydrogen ions are generated from the water vapor. As shown in Figure 1, the water vapor-containing gas can be obtained, for example, by passing an inert gas such as helium through pure water.

[0037] The gas supply unit 12 supplies a water vapor-containing gas so that the low-temperature plasma-formed water vapor comes into contact with the surface 1a of the sample 1 under atmospheric pressure. In the configuration shown in Figure 1, by supplying and filling the space between the sample 1 and the dielectric 11c with water vapor-containing gas, it becomes possible to bring the low-temperature plasma-formed water vapor into contact with the surface 1a. By bringing the low-temperature plasma-formed water vapor into contact with the surface 1a, hydrogen is filled into the sample 1.

[0038] In the configuration shown in Figure 1, the sample 1 and the AC power supply 11e are directly connected. However, the sample 1 may be placed on a conductive sample stand (not shown) and connected indirectly to the AC power supply 11e via the sample stand.

[0039] Figure 2 shows a schematic configuration of a hydrogen filling apparatus 200 according to another embodiment of the present invention. In the configuration shown in Figure 2, the plasma generating unit 21 includes an electrode 21a made of copper foil and a dielectric 21c made of a cylindrical glass capillary. The electrode 21a is provided so as to cover the outer circumference of the dielectric 21c, and the tip of the dielectric 21c protrudes from the electrode 21a toward the sample 2 side.

[0040] Water vapor-containing gas is supplied from the inside of the cylindrical dielectric 21c by the gas supply unit 22 and blown onto the surface 2a of the sample 2 through the tip of the dielectric 21c. In this state, by applying an AC voltage between the sample 2 and the electrode 21a using the AC power supply 21e, the electrode 21a and the sample 2 are electrically connected via the dielectric 21c and the water vapor-containing gas. Dielectric barrier discharge occurs in the water vapor-containing gas inside the dielectric 21c and in the water vapor-containing gas blown onto the surface 2a from the tip of the dielectric 21c, and the water vapor is converted into a low-temperature plasma under atmospheric pressure. This makes it possible to bring the low-temperature plasma-converted water vapor into contact with the surface 2a.

[0041] In the configuration shown in Figure 2, the sample 2 and the AC power supply 21e are directly connected. However, the sample 2 may be placed on a conductive sample stand (not shown) and connected indirectly to the AC power supply 21e via the sample stand.

[0042] Figure 3 shows a schematic configuration of a hydrogen refueling apparatus 300 according to another embodiment of the present invention. In the configuration shown in Figure 3, the plasma generating unit 31 includes a pair of electrodes 31a and 31b made of copper plates and a pair of dielectrics 31c and 31d made of glass plates. Both dielectrics 31c and 31d are provided between the pair of electrodes 31a and 31b, with one dielectric 31c in contact with one electrode 31a and the other dielectric 31d in contact with the other electrode 31b. In the configuration shown in Figure 3, the dielectrics are provided on both sides of the pair of electrodes 31a and 31b, but they may also be provided on only one side.

[0043] The water vapor-containing gas is supplied between the pair of dielectrics 31c and 31d by the gas supply unit 32. In this state, by applying an AC voltage between the pair of electrodes 31a and 31b using the AC power supply 31e, the pair of electrodes 31a and 31b are electrically connected via the dielectrics 31c and 31d and the water vapor-containing gas, a dielectric barrier discharge occurs in the water vapor-containing gas between the dielectrics 31c and 31d, and the water vapor is converted into a low-temperature plasma under atmospheric pressure.

[0044] Furthermore, the gas supply unit 32 can bring low-temperature plasma-formed water vapor into contact with the surface 3a by adjusting the supply direction, flow rate, and flow velocity of the water vapor-containing gas supplied between the pair of dielectrics 31c and 31d so that the water vapor-containing gas is blown onto the surface 3a of the sample 3.

[0045] In the configuration shown in Figure 3, sample 3 is grounded, but it is not necessarily required to ground it.

[0046] Figure 4 shows a schematic configuration of a hydrogen filling apparatus 400 according to another embodiment of the present invention. In the configuration shown in Figure 4, the plasma generating unit 41 includes a pair of electrodes 41a and 41b made of copper foil and a dielectric 41c made of a cylindrical glass capillary. The pair of electrodes 41a and 41b are provided so as to cover the outer circumference of the dielectric 41c, and the tip of the dielectric 41c protrudes from the electrode 41b toward the sample 4.

[0047] The water vapor-containing gas is supplied from the inside of the cylindrical dielectric 41c by the gas supply unit 42 and blown onto the surface 4a of the sample 4 through the tip of the dielectric 41c. In this state, by applying an AC voltage between the pair of electrodes 41a and 41b using the AC power supply 41e, the pair of electrodes 41a and 41b are electrically connected via the dielectric 41c and the water vapor-containing gas, a dielectric barrier discharge occurs in the water vapor-containing gas inside the dielectric 41c, and the water vapor is converted into a low-temperature plasma under atmospheric pressure. As described above, since the water vapor-containing gas is blown onto the surface 4a through the tip of the dielectric 41c, it is possible to bring the low-temperature plasma-converted water vapor into contact with the surface 4a.

[0048] In the configuration shown in Figure 4, sample 4 is grounded, but it is not necessarily required to ground it.

[0049] Figure 5 shows a schematic configuration of a hydrogen filling apparatus 500 according to another embodiment of the present invention. In the configuration shown in Figure 5, the plasma generating unit 51 includes an electrode 51a made of copper foil and a dielectric 51c made of a cylindrical glass capillary. The electrode 51a is provided so as to cover the outer circumference of the dielectric 51c, and the tip of the dielectric 51c protrudes from the electrode 51a toward the sample 5.

[0050] Then, a predetermined gas capable of being converted into a low-temperature plasma (hereinafter, an example of a gas capable of being converted into a low-temperature plasma will be referred to as "inert gas," but it is not limited to this) is supplied from inside the cylindrical dielectric 51c and blown onto the surface 5a of the sample 5 through the tip of the dielectric 51c. In this state, by applying an AC voltage between the sample 5 and the electrode 51a using the AC power supply 51e, the electrode 51a and the sample 5 are electrically connected via the dielectric 51c and the inert gas. Dielectric barrier discharge occurs in the inert gas inside the dielectric 51c and in the inert gas blown onto the surface 5a from the tip of the dielectric 51c, and the inert gas is converted into a low-temperature plasma. Furthermore, in this state, the gas supply unit 52 supplies a gas containing water vapor into the low-temperature plasma-converted inert gas using a nozzle 52a. This allows the water vapor to be converted into a low-temperature plasma under atmospheric pressure, and makes it possible to bring the low-temperature plasma-converted water vapor into contact with the surface 5a. As shown in Figure 5, the gas containing water vapor can be obtained, for example, by passing air through pure water.

[0051] In the configuration shown in Figure 5, the sample 5 and the AC power supply 51e are directly connected. However, the sample 5 may be placed on a conductive sample stand (not shown) and connected indirectly to the AC power supply 51e via the sample stand.

[0052] Figure 6 shows a schematic configuration of a hydrogen filling apparatus 600 according to another embodiment of the present invention. In the configuration shown in Figure 6, the plasma generating unit 61 includes a pair of electrodes 61a and 61b made of copper foil and a dielectric 61c made of a cylindrical glass capillary. The pair of electrodes 61a and 61b are provided so as to cover the outer circumference of the dielectric 61c, and the tip of the dielectric 61c protrudes from the electrode 61b toward the sample 6.

[0053] Then, an inert gas is supplied from the inside of the cylindrical dielectric 61c and blown onto the surface 6a of the sample 6 through the tip of the dielectric 61c. In this state, by applying an AC voltage between the pair of electrodes 61a and 61b using the AC power supply 61e, the pair of electrodes 61a and 61b are electrically connected via the dielectric 61c and the inert gas, a dielectric barrier discharge occurs in the inert gas inside the dielectric 61c, and the inert gas is converted into a low-temperature plasma under atmospheric pressure. Furthermore, in this state, the gas supply unit 62 supplies a gas containing water vapor into the low-temperature plasma-converted inert gas using the nozzle 62a. This causes the water vapor to be converted into a low-temperature plasma under atmospheric pressure, making it possible to bring the low-temperature plasma-converted water vapor into contact with the surface 6a.

[0054] In the configuration shown in Figure 6, sample 6 is grounded, but it is not necessarily required to ground it.

[0055] Regarding a method for supplying a water vapor-containing gas into a low-temperature plasma-generated inert gas after the gas has been plasma-generated at low temperatures, the method described in Figures 5 and 6 uses a configuration with an electrode made of copper foil and a dielectric made of glass capillaries as an example. However, although a detailed explanation is omitted, the above method may also be applied to a configuration using an electrode made of copper plate and a dielectric made of glass plate, as shown in Figure 1 or 3. Furthermore, while the water vapor-containing gas is supplied by a nozzle in the examples shown in Figures 5 and 6, the method is not limited to this. For example, a hydrogen filling device may be placed inside a sealed space, and the water vapor pressure inside the sealed space may be increased to supply the water vapor-containing gas into the low-temperature plasma-generated inert gas.

[0056] Figure 7 shows a schematic configuration of a hydrogen refueling apparatus 700 according to another embodiment of the present invention. In the configuration shown in Figure 7, the hydrogen refueling apparatus 700 includes a temperature control unit 73 in addition to a plasma generation unit 71 and a gas supply unit 72. Note that the configurations of the plasma generation unit 71 and the gas supply unit 72 are the same as those of the plasma generation unit 21 and the gas supply unit 22 shown in Figure 2, so their description is omitted. In the example shown in Figure 7, the configurations of the plasma generation unit 71 and the gas supply unit 72 are the same as those of the plasma generation unit 21 and the gas supply unit 22 shown in Figure 2, but they may also be the same as any of the configurations shown in Figures 1, 3 to 6.

[0057] The temperature control unit 73 controls the temperature of the surface 7a of the sample 7 to a predetermined temperature. For example, it is possible to maintain the temperature of the surface 7a at a high temperature or at a low temperature. With the temperature of the surface 7a controlled to a predetermined temperature, it is possible to fill the sample 7 with hydrogen under various temperature conditions by bringing low-temperature plasma-formed water vapor into contact with the surface 7a under atmospheric pressure. In this invention, since low-temperature plasma is utilized, the effect on the temperature of the surface 7a caused by bringing low-temperature plasma-formed water vapor into contact with the surface 7a under atmospheric pressure can be minimized.

[0058] Figure 8 shows a schematic configuration of a sample analysis device 800 according to one embodiment of the present invention. The sample analysis device 800 is an analysis device for a sample 8 made of metal, and comprises a plasma generation unit 81, a gas supply unit 82, and an analysis unit 83. Note that the configuration of the plasma generation unit 81 and the gas supply unit 82 is the same as that of the plasma generation unit 21 and the gas supply unit 22 shown in Figure 2, so a description is omitted. In the example shown in Figure 8, the configuration of the plasma generation unit 81 and the gas supply unit 82 is the same as that of the plasma generation unit 21 and the gas supply unit 22 shown in Figure 2, but it may also be the same as any of the configurations shown in Figures 1, 3 to 7.

[0059] The analysis unit 83 analyzes the surface 8a of the sample 8 in contact with low-temperature plasma-converted water vapor under atmospheric pressure. In the configuration shown in Figure 8, the analysis unit 83 is an optical microscope, but is not limited to this, and a laser microscope, white light interference microscope, X-ray microscope, ultrasonic microscope, etc., can be used. As described above, in the present invention, since hydrogen can be filled under atmospheric pressure, an optical microscope, etc., can be easily installed and used and has high temporal resolution. Therefore, by performing analysis of the surface 8a using the analysis unit 83 such as an optical microscope, it becomes possible to analyze, for example, the process of hydrogen embrittlement occurring over time with high temporal resolution.

[0060] In the above description, there are no particular restrictions on the type of sample as long as it is a metal, and examples include carbon steel, alloy steel, stainless steel, Ni-based alloys, Al alloys, Ti alloys, etc. In particular, carbon steel has a large hydrogen diffusion coefficient, and it is difficult to maintain it in a hydrogen-filled state for a long time under atmospheric pressure. For this reason, the hydrogen filling method, hydrogen filling apparatus, sample analysis method, and sample analysis apparatus according to the present invention can be suitably used when dealing with carbon steel.

[0061] Furthermore, there are no particular restrictions on the shape of the sample; for example, it may be plate-shaped, cylindrical, or even the shape of an actual product (e.g., a bolt). There are also no particular restrictions on the dimensions of Sample 1. For example, it may be a part (cut end face or joint) of a component on the order of several meters in size, such as an automobile housing, or it may be a micro-test piece on the order of several millimeters in size.

[0062] In the configurations shown in Figures 1-4, 7, and 8, the water vapor-containing gas used for generating low-temperature plasma is preferably a mixture of an inert gas (noble gas, nitrogen, carbon dioxide) and water vapor. More preferably, it is a mixture of helium and water vapor. The reasons for this preference are that it is easy to control the discharge and no chemical reaction occurs with the sample. The predetermined gas capable of generating low-temperature plasma as described above is also preferably an inert gas (noble gas, nitrogen, carbon dioxide), and more preferably helium.

[0063] On the other hand, the water vapor-containing gas supplied to the low-temperature plasma-treated inert gas used in the configurations shown in Figures 5 and 6 may be a mixture of inert gas and water vapor, or a mixture of air and water vapor. Considering the cost, it is preferable to use a mixture of air and water vapor.

[0064] There are no particular restrictions on the water vapor pressure in the water vapor-containing gas supplied to the water vapor-containing gas used for generating low-temperature plasma and the water vapor-containing gas supplied to the low-temperature plasma-treated inert gas, as long as it is below the saturation water vapor pressure. However, if the water vapor pressure is too low, there is a risk that a sufficient amount of hydrogen will not be filled into the sample, so it is preferable that it be 0.05 kPa or higher.

[0065] There are no particular restrictions on the AC voltage conditions as long as dielectric barrier discharge occurs, and it is preferable that the frequency be 0.01 kHz to 1000 kHz and the voltage amplitude be 1 kV to 100 kV. The waveform of the AC voltage may be a trapezoidal wave, square wave, triangular wave, etc., in addition to a sine wave. There are also no particular restrictions on the distance between the dielectric and the sample as long as dielectric barrier discharge occurs, and it can be, for example, 1 mm to 50 mm.

[0066] Suitable materials for electrodes and sample stages include copper, silver, aluminum, and iron, which have good conductivity. Suitable materials for dielectrics include glass, ceramic materials such as alumina and aluminum nitride, and polymers.

[0067] In this invention, "atmospheric pressure" refers to an environment of approximately 100 kPa. This is intended to distinguish it from vacuum and high-pressure environments, and it does not need to be strictly 1 atmosphere. Furthermore, low-temperature plasma refers to plasma in which the temperature of the gas in the plasma (hereinafter also referred to as plasma temperature) is 800°C or lower.

[0068] If the plasma temperature is too high, the sample may suffer thermal damage. The plasma temperature is more preferably 700°C or lower, even more preferably 400°C or lower, and even more preferably 200°C or lower. Furthermore, low-temperature plasma can be kept at room temperature (around 30°C), making it extremely safe. The plasma temperature can be controlled by adjusting the frequency, voltage amplitude, or gas flow rate of the AC voltage.

[0069] Furthermore, in the configuration illustrated above, water vapor is converted into a low-temperature plasma under atmospheric pressure by generating a dielectric barrier discharge. Dielectric barrier discharge is preferred because it is easy to control the discharge, the equipment is inexpensive, it is highly safe, and the discharge is uniform. However, it is not limited to this, and other methods for converting water vapor into a low-temperature plasma under atmospheric pressure include corona discharge, microwave discharge, and RF discharge.

[0070] The present invention will be described more specifically below with reference to examples, but the present invention is not limited to these examples. [Examples]

[0071] As-quenched JIS-SCM435 steel (tensile strength 1.9 GPa) was used as the sample. A test piece with the dimensions and shape shown in Figure 9 was taken from this sample, and a wedge with the dimensions and shape shown in Figure 10 was inserted into the notch to introduce a pre-crack. The wedge was held in place while the test piece was subjected to a constant strain.

[0072] Subsequently, using the sample analysis apparatus shown in Figure 8, hydrogen was filled into the sample by blowing a low-temperature plasma-containing water vapor gas near the tip of the pre-crack, while in-situ observation with an optical microscope was performed. The water vapor-containing gas was a mixture of helium and water vapor, with a water vapor pressure of 2 kPa and a flow rate of 200 mL / min. As shown in Figure 8, the water vapor-containing gas was obtained by passing helium through pure water. The frequency of the AC voltage was set to 1 kHz and the voltage amplitude to 10 kV.

[0073] As a result, it was possible to observe how cracks propagate due to hydrogen embrittlement. Furthermore, observation of the cracks at higher magnification confirmed that they were intergranular cracks, which are characteristic of hydrogen embrittlement cracks. [Industrial applicability]

[0074] According to the present invention, it is possible to fill a sample with hydrogen under atmospheric pressure, which is highly safe and low-cost, and furthermore, to analyze the sample surface over time with high temporal resolution under atmospheric pressure while filling the sample with hydrogen. [Explanation of symbols]

[0075] 1,2,3,4,5,6,7,8. Samples 1a,2a,3a,4a,5a,6a,7a,8a.Surface 11,21,31,41,51,61,71,81. Plasma generation section 11a,21a,31a,31b,41a,41b,51a,61a,61b,71a,81a.Electrode 11c, 21c, 31c, 31d, 41c, 51c, 61c, 71c, 81c. Dielectric. 11e,21e,31e,41e,51e,61e,71e,81e.AC power supply 12, 22, 32, 42, 52, 62, 72, 82. Gas Supply Department 100, 200, 300, 400, 500, 600, 700. Hydrogen refueling equipment 800. Sample Analysis Device

Claims

1. A method for filling a metal sample with hydrogen, (a) A process of converting water vapor into a low-temperature plasma under atmospheric pressure, (b) The process comprises bringing the low-temperature plasma-converted water vapor into contact with the surface of the sample under atmospheric pressure, Hydrogen refueling method.

2. In step (a) above, the water vapor is converted into a low-temperature plasma under atmospheric pressure by generating a dielectric barrier discharge in the gas containing the water vapor. The hydrogen filling method according to claim 1.

3. In step (a) above, an alternating voltage is applied between the electrode and the sample, and the electrode and the sample are electrically connected via a dielectric and a gas containing water vapor to generate a dielectric barrier discharge. The hydrogen filling method according to claim 2.

4. In step (a) above, an alternating voltage is applied between a pair of electrodes, and the pair of electrodes are electrically connected via a dielectric and a gas containing water vapor to generate a dielectric barrier discharge. The hydrogen filling method according to claim 2.

5. In step (a) above, the predetermined gas is made into a low-temperature plasma by generating a dielectric barrier discharge in a predetermined gas that can be made into a low-temperature plasma, and the water vapor is made into a low-temperature plasma at atmospheric pressure by supplying the water vapor-containing gas into the predetermined gas that has been made into a low-temperature plasma. The hydrogen filling method according to claim 1.

6. In step (a) above, an AC voltage is applied between the electrode and the sample, and the electrode and the sample are electrically connected via a dielectric and the predetermined gas to generate a dielectric barrier discharge. The hydrogen filling method according to claim 5.

7. In step (a) above, an alternating voltage is applied between a pair of electrodes, and the pair of electrodes are electrically connected via a dielectric and the predetermined gas to generate a dielectric barrier discharge. The hydrogen filling method according to claim 5.

8. In step (b) above, while the surface temperature is controlled to a predetermined temperature, the low-temperature plasma-formed water vapor is brought into contact with the surface under atmospheric pressure. A hydrogen filling method according to any one of claims 1 to 7.

9. A device for filling a metal sample with hydrogen, A plasma generation unit that converts water vapor into low-temperature plasma under atmospheric pressure, The system includes a gas supply unit that supplies the water vapor so that the low-temperature plasma-formed water vapor comes into contact with the surface of the sample under atmospheric pressure. Hydrogen refueling device.

10. The plasma generation unit generates a dielectric barrier discharge in the gas containing water vapor, thereby converting the water vapor into a low-temperature plasma under atmospheric pressure. The hydrogen filling apparatus according to claim 9.

11. The plasma generation unit includes an electrode and a dielectric, By applying an alternating voltage between the electrode and the sample, and electrically connecting the electrode and the sample via the dielectric and the gas containing water vapor, a dielectric barrier discharge is generated. The hydrogen filling apparatus according to claim 10.

12. The plasma generation unit includes a pair of electrodes and a dielectric, By applying an alternating voltage between the pair of electrodes and electrically connecting the pair of electrodes via the dielectric and the gas containing water vapor, a dielectric barrier discharge is generated. The hydrogen filling apparatus according to claim 10.

13. The plasma generation unit generates a dielectric barrier discharge in a predetermined gas capable of being converted into a low-temperature plasma, thereby converting the predetermined gas into a low-temperature plasma, and supplies a gas containing water vapor into the predetermined gas that has been converted into a low-temperature plasma, thereby converting the water vapor into a low-temperature plasma under atmospheric pressure. The hydrogen filling apparatus according to claim 9.

14. The plasma generation unit includes an electrode and a dielectric, By applying an AC voltage between the electrode and the sample, and electrically connecting the electrode and the sample via the dielectric and the predetermined gas, a dielectric barrier discharge is generated. The hydrogen filling apparatus according to claim 13.

15. The plasma generation unit includes a pair of electrodes and a dielectric, By applying an AC voltage between the pair of electrodes and electrically connecting the pair of electrodes via the dielectric and the predetermined gas, a dielectric barrier discharge is generated. The hydrogen filling apparatus according to claim 13.

16. The system further includes a temperature control unit that controls the temperature of the surface to reach a predetermined temperature. The gas supply unit supplies water vapor such that the low-temperature plasma-formed water vapor comes into contact with the surface under atmospheric pressure while the surface temperature is controlled to a predetermined temperature. A hydrogen filling apparatus according to any one of claims 9 to 15.

17. A method for analyzing a sample made of metal, The steps of (a) and (b) described in any one of claims 1 to 7, (c) The process includes a step of analyzing the surface in which the low-temperature plasma-converted water vapor has come into contact with the surface under atmospheric pressure, Sample analysis method.

18. A method for analyzing a sample made of metal, The steps of (a) and (b) described in claim 8, (c) The process includes a step of analyzing the surface in which the low-temperature plasma-converted water vapor has come into contact with the surface under atmospheric pressure, Sample analysis method.

19. An analytical apparatus for samples made of metal, The plasma generating unit and the gas supply unit according to any one of claims 9 to 15, (c) The system comprises an analysis unit that analyzes the surface in which the low-temperature plasma-converted water vapor has come into contact with the surface under atmospheric pressure, Sample analysis device.

20. An analytical apparatus for samples made of metal, The plasma generating unit and the gas supply unit according to claim 16, (c) The system comprises an analysis unit that analyzes the surface in which the low-temperature plasma-converted water vapor has come into contact with the surface under atmospheric pressure, Sample analysis device.

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