Electrochemical hydrogen permeation cell

Abstract

An electrochemical hydrogen permeation cell capable of shortening the test time required for an electrochemical hydrogen permeation test. [Solution] The present invention relates to an electrochemical hydrogen permeation cell, comprising a first electrolytic vessel 10 having a hollow polygonal prism shape with an N-sided base (N is an integer between 3 and 8) and with an opening provided on at least a portion of at least two of its side surfaces, and a plurality of second electrolytic vessels 20A, 20B having a hollow rectangular prism shape and with an opening provided on one of its side surfaces, wherein the opening of the second electrolytic vessel can be arranged to face the opening on any of the side surfaces of the first electrolytic vessel at a predetermined interval, and a metal material M to be evaluated is respectively arranged between the opening of the second electrolytic vessel and the opening of the first electrolytic vessel, thereby enabling the first electrolytic vessel and the second electrolytic vessel to hold an electrolyte solution in their respective hollow portions.

Description

Technical Field

[0001] The present invention relates to an electrochemical hydrogen permeation cell.

Background Art

[0002] When metal materials including various steel materials contain hydrogen, their toughness is lost and their strength is significantly reduced. Such a phenomenon is called hydrogen embrittlement. The occurrence of hydrogen embrittlement involves hydrogen that has penetrated into the metal material. Therefore, in order to verify the penetration of such hydrogen, an electrochemical hydrogen permeation test (hereinafter sometimes abbreviated as "hydrogen permeation test") is widely used as a test method capable of measuring the amount of hydrogen penetrating into a metal material (for example, see Non-Patent Document 1 below).

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The electrochemical hydrogen permeation test as disclosed in Non-Patent Document 1 above requires time to adjust test conditions (for example, removing bubbles on the liquid surface of the electrolyte solution used, stabilizing the liquid temperature of the electrolyte solution, etc.). In addition, since it is necessary to attach the metal material to be measured and exchange the electrolyte solution for each measurement, there is a problem that the test time becomes long. In particular, the longer the test time becomes as the number of metal materials of interest increases, and there has been a demand for improving the convenience of the test method.

[0005] Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide an electrochemical hydrogen permeation cell capable of shortening the test time required for an electrochemical hydrogen permeation test and easily performing an electrochemical hydrogen permeation test on a larger number of metal materials.

Means for Solving the Problem

[0006] As a result of intensive studies by the present inventor to solve the above problems, it was found that in a measurement cell used for an electrochemical hydrogen permeation test, if the number of metal materials that can be attached at one time can be increased, the number of metal materials that can be evaluated in one measurement increases, and as a result, the overall test time can be shortened. Based on such findings, the gist of the present invention completed is as follows.

[0007] (1) An electrochemical hydrogen permeation cell used in an electrochemical hydrogen permeation test for evaluating the hydrogen permeability of a metal material, having a hollow polygonal column shape with an N-gon (N is a parameter representing the number of sides, an integer of 3 or more and 8 or less) as the bottom surface, and having openings provided in at least a part of two or more side surfaces respectively; and a plurality of second electrolytic containers having a hollow square column shape and having an opening provided in one of the side surfaces, wherein the opening of the second electrolytic container can be arranged to face the opening in any of the side surfaces of the first electrolytic container with a predetermined interval therebetween, and the metal materials to be evaluated are respectively arranged between the opening of the second electrolytic container and the opening of the first electrolytic container, so that the first electrolytic container and the second electrolytic container can hold an electrolyte solution in their respective hollow parts, the electrochemical hydrogen permeation cell. (2) The electrochemical hydrogen permeation cell according to (1), wherein the number of the second electrolytic containers arranged on the side surface of the first electrolytic container is 2 or more and 8 or less. (3) The electrochemical hydrogen permeation cell according to (1) or (2), wherein at the opening provided in the second electrolytic container, the opening area of the opening on the side not in contact with the metal material to be evaluated is larger than the opening area of the opening on the side in contact with the metal material. (4) The electrochemical hydrogen permeation cell according to (1) or (2), wherein the volume of each of the second electrolytic containers is smaller than the volume of the first electrolytic container. (5) A detachable lid is provided on the top surface of the polygonal prism shape in the first electrolytic capacitor and on the top surface of the square prism shape in each of the second electrolytic capacitors, and a hole for attaching an electrode to each of the electrolytic capacitors is provided in each of the lids. The electrochemical hydrogen permeation cell according to (1) or (2). (6) In the first electrolytic capacitor, a plurality of the openings are provided for one of the side surfaces. The electrochemical hydrogen permeation cell according to (1) or (2).

Advantages of the Invention

[0008] As described above, according to the present invention, it is possible to shorten the test time required for the electrochemical hydrogen permeation test and to easily perform the electrochemical hydrogen permeation test on more metal materials.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 6A

Figure 6B

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0011] (Regarding the test time of the electrochemical hydrogen permeation test method) Prior to describing the electrochemical hydrogen permeation cell according to the embodiment of the present invention, the electrochemical hydrogen permeation test method using the electrochemical hydrogen permeation cell will be briefly described.

[0012] As mentioned above, metal materials including various steel materials can lose toughness and hydrogen embrittlement can occur when they contain hydrogen. In particular, in automotive steel sheets used as materials for vehicles such as automobiles, the occurrence of hydrogen embrittlement may become apparent with the required increase in the strength of the steel sheets. Here, the intrusion of hydrogen into the steel sheet that causes hydrogen embrittlement can occur from the time of manufacturing the automotive steel sheet to the time of using the automobile.

[0013] For example, during the manufacture of automobiles, in the preheating process before pressing in the hot stamping process for processing automotive steel sheets into a desired shape, or in the electrocoating process of applying electrocoating to the surface of the automotive steel sheet after processing it into a desired shape, it is known that hydrogen penetrates into the steel sheet. Also, during the use of automobiles, it is known that hydrogen penetrates into the steel sheet during the process of corrosion of the members where the steel sheet is used.

[0014] Based on the above situation, it is important to grasp the amount of hydrogen that can penetrate into the steel sheet (penetrated hydrogen amount). As a method capable of measuring such an amount of penetrated hydrogen, there is an electrochemical hydrogen permeation test method.

[0015] Such an electrochemical hydrogen permeation test method is a test method capable of precisely measuring the amount of penetrated hydrogen from an arbitrary environment. However, in the electrochemical hydrogen permeation test method, in order to realize appropriate test conditions (for example, removal of bubbles on the liquid surface and stabilization of the liquid temperature in the electrolyte solution used in the test), it takes time. In addition, for each measurement, the metal material to be tested must be attached to the electrochemical hydrogen permeation cell and the electrolyte solution must be exchanged, resulting in a longer test time.

[0016] Regarding the above-mentioned prolongation of the test time, the present inventor verified the test time for measuring the amount of penetrated hydrogen during electrocoating, where it is difficult to adjust the test conditions, for measuring the amount of penetrated hydrogen of a single automotive steel sheet. As a result, it was found that it takes approximately 60 minutes to measure the amount of penetrated hydrogen of a single automotive steel sheet. Looking at the breakdown of that test time, a lot of time was required for temperature adjustment of the electrolyte solution, waste liquid disposal of the electrolyte solution after the test, and cleaning of the electrochemical hydrogen permeation cell after the test in preparation for measurement of the next sample.

[0017] Based on such a situation, the present inventor obtained the idea that by installing a plurality of measurement samples in the electrochemical hydrogen permeation cell, it is possible to shorten the test time required for the electrochemical hydrogen permeation test, and thus completed the electrochemical hydrogen permeation cell according to the present invention as described in detail below.

[0018] (Regarding an Electrochemical Hydrogen Permeation Cell) Hereinafter, the electrochemical hydrogen permeation cell according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, for convenience, the coordinate system shown in FIG. 1 will be appropriately used for the description.

[0019] (Regarding the Overall Configuration of the Electrochemical Hydrogen Permeation Cell) FIG. 1 is an explanatory diagram schematically showing an example of the electrochemical hydrogen permeation cell 1 according to the present embodiment, and is a plan view when the electrochemical hydrogen permeation cell 1 according to the present embodiment is viewed from above (the positive Z-axis direction side in FIG. 1). Further, FIG. 2 is a cross-sectional view when the electrochemical hydrogen permeation cell 1 shown in FIG. 1 is cut along the A-A cutting line.

[0020] The electrochemical hydrogen permeation cell 1 as exemplified in FIG. 1 is used in an electrochemical hydrogen permeation test for evaluating the hydrogen permeability of various metal materials M. As shown in FIGS. 1 and 2, the electrochemical hydrogen permeation cell 1 according to the present embodiment has a hollow polygonal column shape with a square as the bottom surface, and first electrolytic containers 10 each having openings 11 provided in a part of at least two or more side surfaces, and a plurality of second electrolytic containers 20 each having a hollow square column shape and an opening 21 provided in one of the side surfaces.

[0021] In FIGS. 1 and 2, a case is illustrated in which openings 11A and 11B are respectively provided in a part of two side surfaces (more specifically, two side surfaces arranged perpendicular to the X-axis direction) of the first electrolytic container 10. Further, in FIGS. 1 and 2, a case is illustrated in which two second electrolytic containers 20A and 20B are provided as the second electrolytic containers 20.

[0022] As illustrated in FIGS. 1 and 2, the openings 21A and 21B of the second electrolytic capacitors 20A and 20B can be arranged to face the openings 11A and 11B on two side surfaces of the first electrolytic capacitor 10 with a predetermined interval therebetween. Further, by arranging the metal materials M to be evaluated between the opening 21 of the second electrolytic capacitor 20 and the opening 11 of the first electrolytic capacitor 10 respectively, the opening 11 in the first electrolytic capacitor 10 and the opening 21 in the second electrolytic capacitor 20 are closed by the metal materials M, and the first electrolytic capacitor 10 and the second electrolytic capacitor 20 can hold the electrolyte solution in their respective hollow portions 13, 23A, and 23B. Further, the arranged metal material M has one surface exposed to the electrolyte solution held in the hollow portion 13 of the first electrolytic capacitor 10 and the other surface exposed to the electrolyte solution held in the hollow portion 23 of the second electrolytic capacitor 20.

[0023] As illustrated in FIGS. 1 and 2, the electrochemically hydrogen permeable cell 1 according to the present embodiment is composed of one first electrolytic capacitor 10 and a plurality of second electrolytic capacitors 20, and for one constructed electrochemically hydrogen permeable cell 1, the number of metal materials M corresponding to the number of the second electrolytic capacitors 20 can be arranged. Thereby, by using the electrochemically hydrogen permeable cell 1 according to the present embodiment, the test time required for the electrochemically hydrogen permeation test can be shortened, and it becomes possible to easily perform the electrochemically hydrogen permeation test on more metal materials.

[0024] Here, in the metal material M shown in FIGS. 1 and 2, the thickness of the metal material M in the direction from the first electrolytic capacitor 10 to the second electrolytic capacitor 20 corresponds to the thickness of the metal material M to be focused on. By using the electrochemically hydrogen permeable cell 1 composed of such two types of electrolytic capacitors (the first electrolytic capacitor 10 and the plurality of second electrolytic capacitors 20), knowledge about the amount of hydrogen permeating from the surface on the first electrolytic capacitor 10 side to the surface on the second electrolytic capacitor 20 side in the metal material M can be obtained. By using the obtained knowledge, the hydrogen permeability of the metal material M to be focused on can be evaluated.

[0025] Here, the materials constituting the first electrolytic capacitor 10 and the second electrolytic capacitor 20 are not particularly limited, and any known materials such as various metal materials and various resin materials can be used as long as they can stably hold the electrolyte solution that can be accommodated in the internal space (i.e., the hollow part) of each electrolytic capacitor.

[0026] Also, the sizes (volumes) of the first electrolytic capacitor 10 and the second electrolytic capacitor 20 are not particularly limited, and can be appropriately set according to the size of the metal material M of interest, etc.

[0027] Here, in FIGS. 1 and 2, the case where the volume of the first electrolytic capacitor 10 and the volume of the second electrolytic capacitor 20 are substantially the same is illustrated as an example. However, the volume of the first electrolytic capacitor 10 and the volume of the second electrolytic capacitor 20 may be different.

[0028] For example, in the electrochemical hydrogen permeation cell 1 according to the present embodiment, it is preferable that the volume of each second electrolytic capacitor 20 is smaller than the volume of the first electrolytic capacitor 10.

[0029] In the electrochemical hydrogen permeation test focused on in the present embodiment, the temperature of the electrolyte solution accommodated in each electrolytic capacitor is adjusted. Here, by making the volume of each second electrolytic capacitor 20 smaller than the volume of the first electrolytic capacitor 10, the volume of the electrolyte solution for which the liquid temperature needs to be adjusted can be reduced as a whole for the electrochemical hydrogen permeation cell 1 as compared with the case where the volumes of the first electrolytic capacitor 10 and the second electrolytic capacitor 20 are the same. Thereby, the test time required for the electrochemical hydrogen permeation test can be further shortened.

[0030] Note that the specific value of the volume of the second electrolytic capacitor 20 is not particularly defined. The volume of the second electrolytic solution 20 can be set as appropriate within the range of a volume capable of holding an electrolyte solution having a volume such that the electrodes installed during the electrochemical hydrogen permeation test can be disposed within the hollow portion 23 of the second electrolytic capacitor 20 and can cover the entire surface of the metal material M disposed at the opening 21.

[0031] FIG. 3 is an explanatory diagram for explaining the electrochemical hydrogen permeation cell according to the present embodiment, and shows an example of a cross section when the electrochemical hydrogen permeation cell 1 is cut in the Z-axis direction.

[0032] As schematically shown in FIG. 3, it is preferable that the electrochemical hydrogen permeation cell 1 according to the present embodiment is provided with a detachable lid portion 15 on the quadrangular prism-shaped top surface of the first electrolytic capacitor 10, and it is preferable that detachable lid portions 25A and 25B are provided on the quadrangular prism-shaped top surfaces of the respective second electrolytic capacitors 20A and 20B.

[0033] Further, as schematically shown in FIG. 3, it is preferable that the lid portion 15 is provided with a hole portion 17 for attaching an electrode (more specifically, an anode) to the first electrolytic capacitor 10, and the lid portions 25A and 25B are provided with hole portions 27A and 27B for attaching electrodes (more specifically, a reference electrode and a counter electrode) to the respective second electrolytic capacitors 20.

[0034] As shown in FIG. 3, by providing detachable lid portions 17 and 27 for the respective electrolytic capacitors 10 and 20, excessive volatilization of the electrolyte solution accommodated in each container can be suppressed during the electrochemical hydrogen permeation test, and the volume of the electrolyte solution required for the test can be stably maintained. Further, by making the lid portions 17 and 27 detachable, it becomes possible to easily inject and discharge the electrolyte solution during the preparation and termination of the electrochemical hydrogen permeation test, and the cleaning of each electrolytic capacitor also becomes easy. As a result, it becomes possible to further shorten the test time required for the electrochemical hydrogen permeation test.

[0035] Further, by providing holes 17 and 27 for attaching electrodes to the respective lid portions 17 and 27, it becomes possible to stably hold each electrode during the electrochemical hydrogen permeation test, and the convenience for the user of the electrochemical hydrogen permeation cell 1 can be improved.

[0036] <Regarding the state during use of the electrochemical hydrogen permeation cell 1> Next, with reference to FIG. 4, the state when the electrochemical hydrogen permeation cell 1 according to the present embodiment is used in an electrochemical hydrogen permeation test will be described. FIG. 4 is an explanatory diagram for explaining an example of an electrochemical hydrogen permeation test apparatus using the electrochemical hydrogen permeation cell according to the present embodiment.

[0037] When performing an electrochemical hydrogen permeation test using the electrochemical hydrogen permeation cell 1 according to the present embodiment as described above, as shown in FIG. 4, between the first electrolytic cell 10 and each of the second electrolytic cells 20, the metal materials M1 and M2 to be tested are arranged. Thereby, the hollow portions of the respective electrolytic cells 10 and 20 can hold the electrolyte solution.

[0038] The first electrolyte solution 101 is injected into the hollow portion 13 of the first electrolytic cell 10, the anode 103 is attached, and the lid portion 17 is arranged. Similarly, the second electrolyte solutions 201A and 201B are injected into the hollow portions 23A and 23B of the respective second electrolytic cells 20A and 20B, the reference electrodes 203A and 203B and the counter electrodes 205A and 205B are attached, and the lid portions 27A and 27B are arranged. Thereafter, the anode 103 and each metal material M are electrically connected, and the galvanostat 2 is arranged between the anode 103 and each metal material M. In addition, a potentiostat 3 and an ammeter 4 are arranged between each metal material M and the reference electrodes 203A and 203B and the counter electrodes 205A and 205B. Thereby, an electrochemical hydrogen permeation test apparatus having the electrochemical hydrogen permeation cell 1, various electrodes, measuring instruments, etc. as shown in FIG. 4 is constructed, and the amount of hydrogen permeating into each metal material M can be measured independently of each other.

[0039] Here, as shown in FIG. 4, in the electrochemical hydrogen permeation cell 1 according to the present embodiment, hydrogen is generated on the surface of the metal material M located on the side of the first electrolytic cell 10, and the hydrogen generated inside the metal material M is allowed to penetrate. Hydrogen is withdrawn from the surface of the metal material M located on the side of the second electrolytic cell 20. That is, in the electrochemical hydrogen permeation cell 1 according to the present embodiment, the first electrolytic cell 10 can be regarded as an electrolytic cell on the hydrogen intrusion side (in other words, the evaluation environment side), and it can also be said that it is a container that functions as a so-called cathode cell. Further, in the electrochemical hydrogen permeation cell 1 according to the present embodiment, the second electrolytic cell 20 can be regarded as an electrolytic cell on the hydrogen extraction side, and it can also be said that it is a container that functions as a so-called anode cell.

[0040] ≪Regarding the electrolyte solutions 101 and 201≫ Here, as the electrolyte solutions 101 and 201 accommodated in each of the electrolytic cells 10 and 20, for example, an aqueous sodium hydroxide solution can be used. Further, the concentration of the electrolyte in such electrolyte solutions 101 and 201 is preferably, for example, in the range of 0.05 to 3.00 M (mol).

[0041] ≪Regarding the anode 103≫ Further, regarding the anode 103 disposed in the first electrolytic cell 10, there is no particular limitation, and for example, various known electrodes such as a Pt electrode and an iridium oxide (IrO 2 ) electrode can be used.

[0042] Note that the electrode area of the anode 103 is not particularly defined, and it may be an electrode area that can obtain a desired anode potential. As a method for confirming the electrode area of the anode 103 for the anode 103 to take a desired anode potential at the current density applied during measurement, for example, a method of confirming the relationship between the current density and the electrode potential of the anode 103 by previously performing an anodic polarization measurement of the anode 103 can be mentioned. The electrode area of the anode 103 may be appropriately set within the range allowed by the test environment according to the test environment such as the size of the first electrolytic cell 10.

[0043] <<Regarding the reference electrode 203>> In addition, the reference electrode 203 is provided to accurately control the potential of the metal material M. Such a reference electrode 203 is not particularly limited, and various known standard electrodes can be used. As such a standard electrode, for example, a hydrogen electrode (Pt - Pt|H 2 |HCl, abbreviated as "SHE".), a saturated calomel electrode (Hg|Hg 2 Cl 2 |saturated KCl, abbreviated as "SCE".), a silver - silver chloride electrode (Ag|AgCl|saturated KCl, abbreviated as "Ag|AgCl".), a mercury - mercuric oxide electrode (Hg|HgO|1M NaOH), etc. can be mentioned.

[0044] <<Regarding the counter electrode 205>> The counter electrode 205 is an electrode used to apply a predetermined potential difference to the metal material M. More specifically, a potential difference capable of extracting hydrogen to the surface of the metal material M on the side facing the second electrolytic cell 20 is applied between the counter electrode 205 and the metal material M. As a result, hydrogen atoms are extracted from the inside of the metal material M as hydrogen ions, and a current corresponding to the amount of the extracted hydrogen ions flows through the electrical circuit composed of the metal material M, the counter electrode 205, and the electrolyte solution 201 held in the second electrolytic cell 20.

[0045] The counter electrode 205 as described above is not particularly limited, and any electrode can be used as long as no unintended electrolytic reaction occurs. Examples of the electrode that can be used as the counter electrode 205 include a Pt electrode.

[0046] In addition, the electrode area of the counter electrode 205 is not particularly specified, and it may be set to an electrode area that can obtain a desired current density. The electrode area of the counter electrode 205 may be appropriately set within the range allowed by the test environment according to the test environment such as the size of the second electrolytic cell 20.

[0047] <<Regarding the galvanostat 2>> For the anode 103, the first electrolyte solution 101, and the electrical circuit composed of the metal material M, as shown in FIG. 4, it is preferable to provide a galvanostat 2. By providing the galvanostat 2, it becomes possible to accurately control the current flowing through the electrical circuit. Thereby, while keeping the amount of current flowing through the above electrical circuit constant, the current density in the anode 103 and the metal material M is precisely controlled so that the amount of hydrogen generation on the surface of the metal material M can be precisely controlled, and it becomes possible to further improve the measurement accuracy.

[0048] Such a galvanostat 2 is not particularly limited, and various commercially available galvanostats can be appropriately used.

[0049] ≪Regarding the potentiostat 3 and the ammeter 4≫ For the counter electrode 205, the second electrolyte solution 201, and the electrical circuit composed of the metal material M, as shown in FIG. 4, it is preferable to provide a potentiostat 3 and an ammeter 4.

[0050] By providing the potentiostat 3, it becomes possible to accurately control the potential difference applied between the counter electrode 205 and the metal material M. Thereby, while keeping the potential difference applied between the counter electrode 205 and the metal material M constant, the amount of hydrogen extraction on the surface of the metal material M can be precisely controlled, and it becomes possible to further improve the measurement accuracy.

[0051] Such a potentiostat 3 is not particularly limited, and various commercially available potentiostats can be appropriately used.

[0052] Also, by providing the ammeter 4, it becomes possible to measure the amount of current flowing through the electrical circuit, which changes according to the amount of hydrogen ions extracted. By paying attention to such an amount of current, it becomes possible to evaluate the hydrogen permeability of the metal material M that is the test object.

[0053] The measurement result of the current amount by such an ammeter 4 is preferably output to, for example, a computer (not shown) or the like. Thereby, it becomes possible to automate the evaluation process of hydrogen permeability in a computer or the like which is the output destination of the measurement result of the current amount.

[0054] Such an ammeter 4 is not particularly limited, and various commercially available ammeters can be appropriately used.

[0055] ≪Regarding Other Device Configurations≫ In addition, the electrochemical hydrogen permeation test apparatus as illustrated in FIG. 4 preferably further includes a stirring mechanism (not shown) for stirring the electrolyte solutions 101 and 201 accommodated in the respective electrolytic vessels 10 and 20, and a heating mechanism (not shown) for adjusting the temperature of the electrolyte solutions 101 and 201 in addition to the above-described device configuration.

[0056] The stirring mechanism for stirring the electrolyte solutions 101 and 201 is not particularly limited, and for example, various known devices such as a stirring device composed of various stirrers and stirrers can be used. By performing the electrochemical hydrogen permeation test while stirring the electrolyte solutions 101 and 201, it becomes possible to make the liquid temperatures of the electrolyte solutions 101 and 201 more uniform, and it becomes possible to improve the test accuracy.

[0057] In addition, as the heating mechanism for adjusting the temperature of the electrolyte solutions 101 and 201, it is preferable to use an immersion heater for heating the electrolyte solution. By controlling the operating state of the immersion heater using a thermostat or the like, it becomes possible to directly control the liquid temperature as compared with the case of controlling the liquid temperature by a warm bath or the like, the temperature adjustment becomes easier, and it becomes possible to further shorten the test time. Also, as such a heating mechanism, a hot stirrer or the like can be used.

[0058] ≪Regarding the Metal Material M≫ In addition, in this embodiment, the metal plate M to be measured is not particularly limited, and various metal materials such as various steel materials (including various plated steel materials), aluminum materials, zinc materials, etc. can be used as evaluation targets. Further, various metal layers for protecting the base metal material, such as various plating films and vapor deposition films, may be provided on the surface of such a metal material M.

[0059] Note that prior to measuring the amount of hydrogen intrusion, it is preferable to apply Ni plating or Pd plating to the surface of the metal material M on the side of the second electrolytic cell 20 in order to obtain high measurement accuracy. In the hydrogen permeation test, in order to quantify by oxidizing the detected hydrogen, it is preferable that the residual current other than the oxidation current of hydrogen is as small as possible in order to measure even a smaller amount of hydrogen. On the other hand, when the metal material M is a steel material or the like, the surface of the metal material M is covered with a passive film due to anodic polarization in the electrochemical hydrogen permeation cell 1, so that the exchange current density becomes small and the residual current becomes large. From such a viewpoint, by applying Ni plating or Pd plating to the surface of the metal material M on the side of the second electrolytic cell 20, the residual current becomes small and even more minute hydrogen can be detected. Ni plating or Pd plating may be carried out by a general electroplating method, and the bath composition and electrodeposition conditions are not particularly defined. Further, the thickness of the Ni plating or Pd plating is preferably 10 to 100 nm.

[0060] As described above, the electrochemical hydrogen permeation cell 1 according to this embodiment has been described in detail with reference to FIGS. 1 to 4.

[0061] <Regarding the modification> Hereinafter, a modification of the electrochemical hydrogen permeation cell 1 according to this embodiment as described above will be described with reference to the drawings.

[0062] ≪Regarding the shape of the opening 21 in the second electrolytic cell 20≫ FIG. 5 is an explanatory diagram for explaining the electrochemical hydrogen permeation cell according to this embodiment, and shows a partial enlargement of the vicinity of the opening 21 of the second electrolytic cell 20.

[0063] As schematically shown in FIG. 5, in the opening 21 provided in the second electrolytic cell 20, the opening area of the opening 21 on the side not in contact with the metal material M to be evaluated is preferably larger than the opening area of the opening 21 on the side in contact with the metal material M. In order to realize such a state, as schematically shown in FIG. 5, it is preferable that at least a part of the shape of the side surface of the opening 21 has an inclination such as a tapered shape, and it is more preferable that the entire side surface of the opening 21 has an inclination such as a tapered shape.

[0064] When conducting the electrochemical hydrogen permeation test, as schematically shown in FIG. 5, hydrogen gas bubbles are generated on the surface of the metal material M on the side of the second electrolytic cell 20. Here, when there is no inclined shape on the side surface of the opening 21 as shown in FIG. 5, the generated hydrogen gas bubbles stay on the surface of the metal material M, and the area of the metal material M in contact with the electrolyte solution 201 is reduced by the bubbles. As a result, the area of the metal material M in contact with the electrolyte solution 201 may change during the test, making it impossible to perform accurate measurement.

[0065] However, by introducing an inclined shape as schematically shown in FIG. 5, it becomes possible to smoothly float the hydrogen gas bubbles generated on the surface of the metal material M toward the liquid surface of the electrolyte solution 201, and it is possible to prevent the bubbles from staying near the surface of the metal material M. As a result, it becomes possible to perform more accurate measurement.

[0066] ≪Regarding the number of the second electrolytic cells 20≫ Also, in the electrochemical hydrogen permeation cell 1 shown in FIG. 1 and the like, the case where the second electrolytic cells 20 are provided on two side surfaces of the first electrolytic cell 10 having a quadrangular prism shape is illustrated, but the number of the second electrolytic cells 20 provided in the first electrolytic cell 10 is not limited to the example shown in FIG. 1 and the like.

[0067] FIG. 6A and FIG. 6B are explanatory diagrams for explaining a modified example of the electrochemical hydrogen permeation cell according to the present embodiment. For example, as shown in FIG. 6A, three second electrolytic vessels 20A, 20B, and 20C may be installed with respect to the first electrolytic vessel 10 having a quadrangular prism shape. Alternatively, as shown in FIG. 6B, for example, four second electrolytic vessels 20A, 20B, 20C, and 20D may be installed with respect to the first electrolytic vessel 10 having a quadrangular prism shape.

[0068] <<Regarding the shape of the first electrolytic vessel 10>> In addition, in the electrochemical hydrogen permeation cell 1 shown in FIG. 1 and the like, the case where the first electrolytic vessel 10 having a quadrangular prism shape is used is illustrated. However, the shape of the first electrolytic vessel 10 is not limited to the quadrangular prism shape. Hereinafter, it will be specifically described with reference to FIGS. 7 to 12. FIGS. 7 to 12 are explanatory diagrams for explaining a modified example of the electrochemical hydrogen permeation cell according to the present embodiment.

[0069] In the electrochemical hydrogen permeation cell 1 according to the present embodiment, the first electrolytic vessel 10 can have a hollow polygonal prism shape with an N-gon (N is a parameter representing the number of sides and is an integer of 3 or more and 8 or less) as the bottom surface, and openings 11 may be provided on at least a part of two or more side surfaces of such a polygonal prism shape.

[0070] For example, FIG. 7 illustrates the case where the first electrolytic vessel 10 has a triangular prism shape. In the example shown in FIG. 7, openings 11 are provided on the three side surfaces of the first electrolytic vessel 10 having a triangular prism shape, and three second electrolytic vessels 20A, 20B, and 20C are installed.

[0071] For example, FIG. 8 illustrates the case where the first electrolytic vessel 10 has a pentagonal prism shape. In the example shown in FIG. 8, openings 11 are provided on the five side surfaces of the first electrolytic vessel 10 having a pentagonal prism shape, and five second electrolytic vessels 20A, 20B, 20C, 20D, and 20E are installed.

[0072] For example, FIG. 9 illustrates the case where the first electrolytic capacitor 10 has a hexagonal prism shape. In the example shown in FIG. 9, openings 11 are provided on six side surfaces of the first electrolytic capacitor 10 having a hexagonal prism shape, and six second electrolytic capacitors 20A, 20B, 20C, 20D, 20E, and 20F are installed.

[0073] For example, FIG. 10 illustrates the case where the first electrolytic capacitor 10 has a heptagonal prism shape. In the example shown in FIG. 10, openings 11 are provided on seven side surfaces of the first electrolytic capacitor 10 having a heptagonal prism shape, and seven second electrolytic capacitors 20A, 20B, 20C, 20D, 20E, 20F, and 20G are installed.

[0074] For example, FIG. 11 illustrates the case where the first electrolytic capacitor 10 has an octagonal prism shape. In the example shown in FIG. 11, openings 11 are provided on eight side surfaces of the first electrolytic capacitor 10 having an octagonal prism shape, and eight second electrolytic capacitors 20A, 20B, 20C, 20D, 20E, 20F, 20G, and 20H are installed.

[0075] Here, in the first electrolytic capacitor 10 having a polygonal prism shape as illustrated in FIGS. 7 to 11, the shape of the bottom surface of the polygonal prism is preferably an octagon or less. When the shape of the bottom surface of the first electrolytic capacitor 10 is a nonagon or more, the electrochemically hydrogen permeable cell itself becomes large, making it difficult to handle the cell during the electrochemically hydrogen permeation test, and the convenience for the user of the electrochemically hydrogen permeable cell 1 may decrease. The shape of the bottom surface of the first electrolytic capacitor 10 is more preferably a hexagon or less, and even more preferably a pentagon or less.

[0076] Also, in the first electrolytic capacitor 10, a plurality of openings 11 may be provided on one side surface so that a plurality of second electrolytic capacitors 20 are arranged on one side surface. In the example shown in FIG. 12, the case is illustrated where two openings 11 are provided on one side surface of the first electrolytic capacitor 10, and four second electrolytic capacitors 20A, 20B, 20C, and 20D are arranged with respect to the first electrolytic capacitor 10.

[0077] Thus, in the electrochemical hydrogen permeation cell 1 according to this embodiment, by variously changing the shape of the first electrolytic cell 10, a plurality of second electrolytic cells 20 can be arranged with respect to one first electrolytic cell 10, and the test time required for the electrochemical hydrogen permeation test can be shortened.

[0078] When performing an electrochemical hydrogen permeation test by arranging a plurality of metal materials M with respect to one electrochemical hydrogen permeation cell 1, the test order of the metal materials M is not particularly defined. For example, for a plurality of metal materials M, the electrochemical hydrogen permeation test may be started simultaneously, the electrochemical hydrogen permeation test may be performed one by one for the metal materials M, or the electrochemical hydrogen permeation test may be performed in order from the metal materials M that are ready.

[0079] The modification examples of the electrochemical hydrogen permeation cell 1 according to this embodiment have been described in detail above.

Example

[0080] Hereinafter, while showing examples, the electrochemical hydrogen permeation cell according to the embodiment of the present invention will be specifically described. Note that the examples shown below are merely examples of the electrochemical hydrogen permeation cell according to this embodiment, and the electrochemical hydrogen permeation cell according to this embodiment is not limited to the following examples.

[0081] Hereinafter, using an electrochemical hydrogen permeation cell having the shape shown in FIG. 3, the time required for the electrochemical hydrogen permeation test on two steel plates was verified.

[0082] In this verification example, the volume of the second electrolytic capacitor was set to approximately 1 / 4 of the volume of the first electrolytic capacitor, and the opening of the second electrolytic capacitor was provided with a tapered shape as shown in FIG. 5. For the first electrolytic capacitor and the two second electrolytic capacitors, an aqueous sodium hydroxide solution with a concentration of 1 mol / L was contained as the electrolyte solution. Pt electrodes were used for the anode and the counter electrode, and a mercury-mercuric oxide electrode (Hg|HgO|1M NaOH) was used as the reference electrode. A throwing-in heater was installed in each electrolytic capacitor to adjust the liquid temperature while stirring the electrolyte solution.

[0083] From the assembly of the electrochemical hydrogen permeation cell 1 until the test was carried out and the time required to wash the cell was measured, the time required to test two steel plates was 52 minutes. Therefore, it can be seen that the time required to carry out an electrochemical hydrogen permeation test on one steel plate is about 26 minutes. As mentioned previously, considering that when an electrochemical hydrogen permeation test was carried out on one steel plate using a conventional electrochemical hydrogen permeation cell, the time required for the test was about 60 minutes, the time required for the electrochemical hydrogen permeation test could be reduced by about 60%.

[0084] As described above, the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that those having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modification examples or correction examples within the scope of the technical idea described in the utility model registration claims, and it is naturally understood that these also belong to the technical scope of the present invention.

[0085] The embodiments disclosed this time are illustrative in all respects and not restrictive. The above embodiments may be omitted, replaced, or modified in various forms without departing from the scope of the invention as defined in the appended utility model claims and the gist of the invention as described below. For example, the constituent elements of the above embodiments can be arbitrarily combined within a range that does not impair their effects. Further, from such an arbitrary combination, the actions and effects of each constituent element involved in the combination can be naturally obtained, and other actions and other effects that are obvious to those skilled in the art from the description of this specification can also be obtained.

[0086] Also, the effects described in this specification are merely illustrative or exemplary and not restrictive. That is, the technology according to the present invention can exhibit other effects that are obvious to those skilled in the art from the description of this specification, together with or instead of the above effects.

[0087] Note that the following configurations also belong to the technical scope of the present invention. (1) An electrochemical hydrogen permeation cell used in an electrochemical hydrogen permeation test for evaluating the hydrogen permeability of a metal material, having a hollow polygonal column shape with an N-sided polygon (N is a parameter representing the number of sides and is an integer of 3 or more and 8 or less) as the bottom surface, and having openings provided in part of at least two or more side surfaces, a first electrolytic cell; a plurality of second electrolytic cells having a hollow square column shape and having an opening provided in one of the side surfaces; and the opening of the second electrolytic cell can be arranged to face the opening in any of the side surfaces of the first electrolytic cell with a predetermined interval therebetween, and by arranging the metal material to be evaluated between the opening of the second electrolytic cell and the opening of the first electrolytic cell, the first electrolytic cell and the second electrolytic cell can each hold an electrolyte solution in their respective hollow portions, an electrochemical hydrogen permeation cell. (2) The number of the second electrolytic capacitors arranged on the side surface of the first electrolytic capacitor is 2 or more and 8 or less. The electrochemically hydrogen permeable cell according to (1). (3) In the opening provided in the second electrolytic capacitor, the opening area of the opening on the side not in contact with the metal material to be evaluated is larger than the opening area of the opening on the side in contact with the metal material. The electrochemically hydrogen permeable cell according to (1) or (2). (4) The volume of each of the second electrolytic capacitors is smaller than the volume of the first electrolytic capacitor. The electrochemically hydrogen permeable cell according to any one of (1) to (3). (5) A detachable lid is provided on the top surface of the prismatic shape in the first electrolytic capacitor and on the top surface of the square prism shape in each of the second electrolytic capacitors. Each of the lids is provided with a hole for attaching an electrode to each of the electrolytic capacitors. The electrochemically hydrogen permeable cell according to any one of (1) to (4). (6) In the first electrolytic capacitor, a plurality of the openings are provided for one of the side surfaces. The electrochemically hydrogen permeable cell according to any one of (1) to (5).

Explanation of symbols

[0088] 1 Electrochemically hydrogen permeable cell 2 Galvanostat 3 Potentiostat 4 Ammeter 10 First electrolytic capacitor 11A, 11B Opening 13 Hollow part 15 Lid 20 Second electrolytic capacitor 21 Opening 23 Hollow part 25 Lid 27 Hole 101 First electrolyte solution 103 Anode 201 Second electrolyte solution 203 Reference electrode 205 Counter electrode M Metal material

Claims

1. An electrochemical hydrogen permeation cell used in an electrochemical hydrogen permeation test for evaluating hydrogen permeability of a metal material, comprising: a first electrolytic vessel having a hollow polygonal column shape with an N-sided polygon (N is a parameter representing the number of sides and is an integer between 3 and 8) as a bottom surface, and having openings on at least two or more parts of side surfaces; A plurality of second electrolytic vessels each having a hollow rectangular prism shape and each having an opening on one of its side surfaces; It has The opening of the second electrolytic container can be arranged to face the opening on any one of the side surfaces of the first electrolytic container with a predetermined interval therebetween, An electrochemical hydrogen permeation cell in which the metal material to be evaluated is placed between the opening of the second electrolytic container and the opening of the first electrolytic container, respectively, so that the first electrolytic container and the second electrolytic container are each capable of retaining an electrolyte solution in their hollow portions.

2. 2. The electrochemical hydrogen permeation cell of claim 1, wherein the number of the second electrolytic vessels disposed on the side of the first electrolytic vessel is 2 or more and 8 or less.

3. 3. The electrochemical hydrogen permeation cell according to claim 1, wherein the opening in the second electrolytic vessel has an opening area on a side not in contact with the metal material to be evaluated that is larger than an opening area on a side in contact with the metal material.

4. 3. An electrochemical hydrogen permeation cell as claimed in claim 1 or 2, wherein the volume of each of the second electrolytic vessels is less than the volume of the first electrolytic vessel.

5. A removable cover is provided on the polygonal prism-shaped top surface of the first electrolytic container and on the quadrangular prism-shaped top surfaces of each of the second electrolytic containers, 3. The electrochemical hydrogen permeation cell of claim 1, wherein each of said lids is provided with a hole for mounting an electrode for each of said electrolytic vessels.

6. 3. The electrochemical hydrogen permeation cell according to claim 1, wherein a plurality of the openings are provided on one of the side surfaces of the first electrolytic vessel.

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