Electrochemical measurement method and device of hydrogen intruded into non-ferrous metallic material

Abstract

To provide a measurement method of an amount of hydrogen intruded into metal using a test solution optimal for a Mg alloy, which can suppress reduction in residual current on a hydrogen detection side and thickness reduction due to corrosion on a hydrogen introduction side.SOLUTION: When one surface of an analyte 2 composed of a Mg-based metallic material is determined as a surface where hydrogen controlled to a potential or current to cause electrolysis of water is intruded, and the other surface is determined as a hydrogen detection surface controlled to a potential in which a hydrogen atom is oxidized to a hydrogen ion, on the hydrogen intrusion surface side, a first electrochemical cell 1a is provided; the inside of the first electrochemical cell 1a is filled with a saturated Mg (OG)2 aqueous solution; a first reference electrode 3a and a first counter electrode 4a are installed; on the hydrogen detection surface side, a second electrochemical cell 1b is provided; the inside of the second electrochemical cell 1b is filled with an organic solvent which dissolves in water and 0.01% or more and 50% or less of a solution obtained by dissolving an aqueous solution in the organic solvent; a second reference electrode 3b and a second counter electrode 4b are installed; and a first power source 6a and a second power source 6b are provided.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and device for electrochemically measuring hydrogen penetration into a non-ferrous metal material, which is capable of calculating the diffusion coefficient of hydrogen in the non-ferrous metal material at room temperature. [Background technology]

[0002] In recent years, with the increasing strength of metallic materials, there is an increasing risk of "hydrogen embrittlement," in which hydrogen that penetrates into metallic materials embrittles the materials. To clarify the hydrogen embrittlement mechanism and develop new materials that have improved hydrogen embrittlement resistance, a method is required to determine the diffusion rate of hydrogen diffusing through metallic materials. Conventionally, electrochemical hydrogen permeation tests have been used to determine the diffusion rate of hydrogen diffusing through materials, using steel materials as the target (Patent Documents 1 and 2, Non-Patent Documents 1 and 2, etc.).

[0003] The method of detecting hydrogen that has diffused through a sample as an increase or decrease in electric current is called the electrochemical hydrogen permeation method. Determining the hydrogen diffusion rate in steel materials using the electrochemical hydrogen permeation method is described in detail, for example, in Non-Patent Documents 1 and 2. The current due to hydrogen obtained on the hydrogen detection side is very small (generally 10 μA / cm 2 The residual current on the detection side (the iron dissolution current that flows when immersed in an aqueous solution) must be as small as possible (typically 0.1 μA / cm 2 (See below) Up until now, various methods have been used to passivate the surface of steel materials, such as plating the detection surface with Pd or Ni, or using NaOH in the aqueous solution.

[0004] In recent years, non-ferrous light metal materials such as Al alloys and Mg alloys, which have superior specific strength and are lighter than steel, have been increasingly used as structural materials to replace steel. Until now, hydrogen embrittlement problems in metallic materials have been reported mainly for high-strength steels, and most hydrogen embrittlement research has targeted steel materials, but with the recent expansion of the use of non-ferrous materials, research on hydrogen embrittlement in these materials is accelerating. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6172097 [Patent Document 2] Patent No. 5777098 [Non-patent literature]

[0006] [Non-Patent Document 1] Toru Mizuru, Materials and Environment, Vol. 63, pp. 3-9 (2014) [Non-Patent Document 2] Masatoshi Sakairi, Materials and Environment, Vol. 67, pp. 191-196 (2018) [Non-Patent Document 3] MAVDevanathan, Z.Stachurski;Proc. Roy. Soc. London, Ser. A, 270, 90 (1962) Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, when applying hydrogen embrittlement research to non-ferrous metal materials such as Al alloys and Mg alloys, it is expected that the use of electrochemical hydrogen permeation tests, which can easily determine the hydrogen diffusion rate in non-ferrous metal materials, will become more common in the future. However, unlike steel materials, hydrogen permeation tests on non-ferrous metal materials are extremely difficult. The reason for this is that Al alloys and Mg alloys, which are typical examples of non-ferrous metal materials, are prone to corrosion. As mentioned above, the residual current of the sample on the hydrogen detection side is 0.1 μA / cm 2 However, the residual current of Al alloys and Mg alloys is 0.1 μA / cm in aqueous solution. 2 It is difficult to achieve a uniform and easy method of applying Pd plating or Ni plating, as is done with steel materials, and no method has been developed yet for applying Pd plating or Ni plating uniformly and easily. Furthermore, even though a reducing environment was created by applying a cathodic current or cathodic potential on the hydrogen introduction side, there was an issue that the Al alloy and Mg alloy corroded, causing the sample to gradually thin, making it impossible to obtain an accurate hydrogen diffusion rate.

[0008] Specifically, the objective of this study is to simultaneously solve the following two problems that are necessary for conducting electrochemical hydrogen permeation tests on non-ferrous metal materials: (1) Residual current at hydrogen detection side: 0.1 μA / cm 2 below, (2) Suppression of corrosion thinning and formation of corrosion products on the hydrogen inlet side. The present invention is devised to solve these problems, and aims to propose a method and device for electrochemically measuring hydrogen penetration into non-ferrous metal materials using a new electrochemical hydrogen permeation method that uses a test solution that is optimal for non-ferrous metal materials, and that can suppress a decrease in residual current on the hydrogen detection side and thinning due to corrosion on the hydrogen introduction side. [Means for solving the problem]

[0009] [1] The method of the present invention for measuring the amount of hydrogen that penetrates into a non-ferrous metal material is, for example, as shown in FIG. 1, a method for measuring the amount of hydrogen that is generated as a result of corrosion of a specimen 2 made of a non-ferrous metal material and penetrates into the metal by using an electrochemical hydrogen permeation method, in which one surface of the specimen 2 is a hydrogen penetration surface controlled to a potential or current at which hydrogen is generated by electrolysis of water, and the other surface is a hydrogen detection surface controlled to a potential at which hydrogen atoms are oxidized to hydrogen ions. A first electrochemical cell 1a is provided on the hydrogen entry surface side, and a hydrogen permeability of 1 μS / cm or more (2×10 5 Fill the container with an aqueous solution having an electrical conductivity of μS / cm or less, and place a first reference electrode 3a and a first counter electrode 4a therein. A second electrochemical cell 1b is provided on the hydrogen detection surface side, and the inside of the second electrochemical cell 1b is filled with a water-soluble organic solvent and an aqueous solution of the organic solvent with a concentration of 0.01% to 50%, and a second reference electrode 3b and a second counter electrode 4b are provided. In the first electrochemical cell 1a, a first power source 6a is connected to the first reference electrode 3a and the first counter electrode 4a, and when the first power source 6a is for potential control, it applies a potential higher than -10 V and lower than the immersion potential of the specimen 2, and when the first power source 6a is for current control, it applies a potential higher than -0.01 mA / cm 2 More than -100mA / cm 2 Given the following constant current, In the second electrochemical cell 1b, a second power source 6b is connected to the second reference electrode 3b and the second counter electrode 4b, and the second power source 6b applies a potential of 0 V or more and 1 V or less with respect to the standard hydrogen electrode. The residual current after 24 hours of immersion of the specimen 2 is -0.1 μA / cm 2 More than 0.1μA / cm 2 These are as follows:

[0010] [2] In the method for measuring the amount of hydrogen that penetrates into a non-ferrous metal material of the present invention [1], the non-ferrous metal material is preferably beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), zinc (Zn), yttrium (Y), zirconium (Zr), or an alloy containing 50 atomic % or more of these non-ferrous metal elements and having a standard electrode potential lower than that of iron (Fe). [3] In the method [1] or [2] for measuring the amount of hydrogen that penetrates into a non-ferrous metal material of the present invention, preferably, the non-ferrous metal material is an Al-based metal material, and the aqueous solution filled into the first electrochemical cell 1a is a citrate buffer solution (pH 5-9) or a borate buffer solution (pH 5-9). [4] In the method [1] or [2] for measuring the amount of hydrogen that penetrates into a non-ferrous metal material of the present invention, preferably, the non-ferrous metal material is a Mg-based metal material, and the aqueous solution filled into the first electrochemical cell 1a is a 0.001 M to saturated NaOH aqueous solution, a 0.001 M to saturated MgSO4 aqueous solution, or a 0.001 M to saturated Mg(OH)2 aqueous solution. [5] In the method [1] to [4] for measuring the amount of hydrogen that penetrates into a non-ferrous metal material of the present invention, preferably, the water-soluble organic solvent is at least one of ethanol, methanol, 2-propanol, and ethylene glycol, and the amount of the aqueous solution is 0.01% or more and 50% or less.

[0011] [6] The device for measuring the amount of hydrogen that penetrates into a non-ferrous metal material of the present invention is, for example, as shown in FIG. 1, a device for measuring the amount of hydrogen that is generated due to corrosion of a specimen 2 made of a non-ferrous metal material and penetrates into the metal by using an electrochemical hydrogen permeation method, in which one surface of the specimen 2 is a surface into which hydrogen penetrates at a potential at which water is electrolyzed, and the other surface is a hydrogen detection surface controlled to a potential or current at which hydrogen atoms are oxidized to hydrogen ions. The electrochemical cell is provided with a first electrochemical cell 1a on the hydrogen entry surface side, and has a first reference electrode 3a and a first counter electrode 4a immersed in a first electrolyte 7a, and a second electrochemical cell 1b on the hydrogen detection surface side, and has a second reference electrode 3b and a second counter electrode 4b immersed in a second electrolyte 7b. The first electrolyte 7a has a conductivity of 1 μS / cm or more and 2×10 5 an aqueous solution having an electrical conductivity of μS / cm or less and filled into the first electrochemical cell 1a; The second electrolytic solution 7b is a solution of a water-soluble organic solvent and an aqueous solution of 0.01% to 50% of the water in the organic solvent, and is filled in the second electrochemical cell 1b. In the first electrochemical cell 1a, a first power source 6a is connected to the first reference electrode 3a and the first counter electrode 4a, and when the first power source is for potential control, a potential higher than -10 V and lower than the immersion potential of the specimen 2 is applied. When the first power source is for current control, a potential higher than -0.01 mA / cm is applied. 2 More than -100mA / cm 2 Given the following constant current, In the second electrochemical cell 1b, a second power source 6b is connected to the second reference electrode 3b and the second counter electrode 4b, and the second power source applies a potential of 0 V or more and 1 V or less with respect to a standard hydrogen electrode; The residual current of the specimen 2 after immersion for 24 hours is -0.1μA / cm 2 More than 0.1μA / cm 2 These are as follows:

[0012] [7] The method of the present invention for measuring the amount of hydrogen that penetrates into a non-ferrous metal material is, for example, as shown in FIG. 11, a method for measuring the amount of hydrogen that is generated as a result of corrosion of a test piece made of a non-ferrous metal material and penetrates into the metal by using an electrochemical hydrogen permeation method, in which one surface of the test piece is a corroded surface and the other surface is a hydrogen detection surface controlled to a potential at which hydrogen atoms are oxidized to hydrogen ions. The corroding surface is any one of a surface exposed to the atmosphere and subjected to an atmospheric corrosive environment, a surface in contact with water vapor and subjected to a water vapor corrosive environment, and a surface in an aqueous solution corrosive environment; An electrochemical cell 1c is provided on the hydrogen detection surface side, and the inside of the electrochemical cell 1c is filled with a water-soluble organic solvent and an aqueous solution of the organic solvent with a concentration of 0.01% to 50%, and a reference electrode 3c and a counter electrode 4c are provided. In the electrochemical cell 1c, a power source 6c is connected to the reference electrode 3c and the counter electrode 4c, and the power source 6c applies a potential of 0 V or more and 1 V or less with respect to the standard hydrogen electrode; The residual current of the specimen 2 after immersion for 24 hours is -0.1μA / cm 2 More than 0.1μA / cm 2 These are as follows:

[0013] [8] In the method for measuring the amount of hydrogen that penetrates into a non-ferrous metal material of the present invention [7], the non-ferrous metal material is preferably beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), zinc (Zn), yttrium (Y), zirconium (Zr), or an alloy containing 50 atomic % or more of these non-ferrous metal elements and having a standard electrode potential lower than that of iron (Fe). [9] In the method [7] or [8] for measuring the amount of hydrogen that penetrates into a non-ferrous metal material of the present invention, preferably, the water-soluble organic solvent is at least one of ethanol, methanol, 2-propanol, and ethylene glycol, and the amount of the aqueous solution is 0.01% or more and 50% or less.

[0014]

[10] The device for measuring the amount of hydrogen that penetrates into a non-ferrous metal material of the present invention is, for example, as shown in FIG. 11, a device for measuring the amount of hydrogen that is generated due to corrosion of a test piece made of a non-ferrous metal material and penetrates into the metal by using an electrochemical hydrogen permeation method, in which one surface of the test piece is a corroded surface and the other surface is a hydrogen detection surface controlled to a potential at which hydrogen atoms are oxidized to hydrogen ions. an environment exposed to the atmosphere, a water vapor environment, or an aqueous solution corrosive environment provided on the corroding surface side; an electrochemical cell 1c provided on the hydrogen detection surface side and having a reference electrode 3c and a counter electrode 4c immersed in a third electrolyte 7c; The third electrolytic solution 7c is a solution of a water-soluble organic solvent and an aqueous solution of 50% or less in the organic solvent, and is filled in the electrochemical cell 1c. In the electrochemical cell 1c, a power source 6c is connected to the reference electrode 3c and the counter electrode 4c, and the power source 6c is applied with a potential of 0 V or more and 1 V or less with respect to a standard hydrogen electrode; The residual current of the specimen 2 after immersion for 24 hours is -0.1μA / cm 2 More than 0.1μA / cm 2 These are as follows: Effect of the Invention

[0015] The method for measuring the amount of hydrogen that penetrates into non-ferrous metal materials of the present invention can measure the hydrogen diffusion coefficient due to hydrogen penetration in an aqueous solution environment at room temperature, and therefore can measure the hydrogen diffusion coefficient in an actual usage environment (i.e., hydrogen that penetrates due to corrosion) with a small error. In addition, since an organic solvent or aqueous solution that is inexpensive and easy to handle is used as the solution, the test is easy to carry out and there is no need to introduce expensive equipment. According to the method of the present invention for measuring the amount of hydrogen that has penetrated into non-ferrous metal materials, the residual current is reduced to 0.1 μA / cm in a short time immediately after immersion by using an organic solvent. 2 The waiting time can be made very short because: [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram of an electrochemical hydrogen permeation test device (Devanathan-Stachurski cell) used in the present invention. [Diagram 2] FIG. 1 is a diagram showing the residual current of pure iron when polarized in each solution, illustrating an example of the present invention and a comparative example. [Diagram 3] FIG. 2 is a graph showing the hydrogen permeation current of pure iron, illustrating one embodiment of the present invention. [Figure 4] FIG. 1 is a diagram showing the residual current of pure Mg polarized in each solution, showing an example of the present invention and a comparative example. [Diagram 5] FIG. 1 shows an example of the present invention, illustrating the change in the surface of pure Mg on the hydrogen introduction side, in which (A) shows the specimen surface when saturated Mg(OH)2 is used, (B) shows the cross-sectional shape of the white dotted line part in (A), and (C) is an enlarged view of the vertical axis of (B). [Figure 6] FIG. 1 shows a comparative example of the present invention, in which (A) shows the surface of a specimen when a 0.1 M NaOH aqueous solution is used, and (B) shows the cross-sectional shape of the area surrounded by the white dotted line in (A). [Figure 7] FIG. 1 shows a comparative example of the present invention, in which (A) shows the surface of a specimen when a 0.1M MgSO4 aqueous solution is used, and (B) shows the cross-sectional shape of the area surrounded by the white dotted line in (A). [Figure 8] FIG. 2 is a graph showing the hydrogen permeation current of pure Mg and AZ31 according to an embodiment of the present invention, in which (A) shows a linear axis on the horizontal axis, and (B) shows a logarithmic axis on the horizontal axis. [Figure 9] FIG. 2 is a graph showing the long-term hydrogen permeation current of AZ31 according to one embodiment of the present invention, in which (A) shows a linear horizontal axis and (B) shows a logarithmic horizontal axis. [Figure 10]FIG. 2 is a graph showing a hydrogen permeation current of pure Al, illustrating one embodiment of the present invention. [Figure 11] FIG. 1 is a schematic diagram of an electrochemical hydrogen permeation test device (improved Devanathan-Stachurski cell) showing another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Examples of the present invention are shown below. The specimens used are pure Mg, AZ31 (Mg alloy), and pure Al in the examples, and pure iron in the comparative example. Note that in this specification, the electric potential is expressed based on the SHE standard, such as ○V (vs. SHE). SHE stands for Standard Hydrogen Electrode.

[0018] In the method of the present invention for measuring the amount of hydrogen that penetrates into a metal, the amount of hydrogen that is generated due to corrosion of a metal material and penetrates into the interior is measured by applying the measurement principle of electrochemical hydrogen permeation method. By exposing the hydrogen penetration surface of the metal material specimen to a corrosive environment, hydrogen generated during corrosion penetrates into the metal material specimen, and the amount of penetrated hydrogen is measured by extracting hydrogen from the opposite surface.

[0019] The electrochemical hydrogen permeation method is a technique developed by Devanathan and Stachurski in 1962 (Non-Patent Document 3), in which two electrolytic cells 1a and 1b are arranged facing each other with a single specimen 2 in between, as shown diagrammatically in Fig. 1. In the example shown in the figure, the specimen surface of the left electrolytic cell 1a is cathodically polarized at a constant potential or constant current to generate and charge hydrogen, while in the right electrolytic cell 1b, the specimen 2 is anodically polarized at a constant potential to oxidize the hydrogen that has permeated the specimen 2 to hydrogen ions, and the amount of hydrogen that has permeated is determined from the current value. In the figure, references 3a and 3b are reference electrodes, 4a and 4b are electrodes, and 4b is called a counter electrode or a coefficient electrode. The electrode 4a is connected to a power source 6a, which is a potentiostat that applies a constant potential or a galvanostat that applies a constant current, and the other electrode 4b is connected to a power source 6b, which is a potentiostat that applies a constant potential. The references 5a and 5b are O-rings that bring the metal sample 2 and the electrolytic cells 1a and 1b into close contact with each other to prevent leakage. The electrolytic cell 1a is filled with an electrolyte 7a, which enables electrical conduction between the reference electrode 3a and the counter electrode 4a as well as the specimen 2. The electrolyte 7a may be, for example, an electrolyte having a conductivity of 1 μS / cm or more and 2×10 at 25° C. 5 An aqueous solution with an electrical conductivity of 1 μS / cm or less is used. The range of electrical conductivity is set at 1 μS / cm or more, which is the same as distilled water, and 1 M KCl aqueous solution (1.28×10 5 μS / cm) with a margin of 2 × 10 5 The value is set to μS / cm or less. The electrolytic cell 1b is filled with an electrolyte 7b, which enables electrical conduction between the reference electrode 3b, the counter electrode 4b, and the specimen 2. As the electrolyte 7b, for example, a water-soluble organic solvent or an aqueous solution of 0.01% to 50% of the organic solvent may be filled. The lower limit of 0.01% or more of the aqueous solution dissolved in the organic solvent is set to the purity of the organic solvent that is commercially available.

[0020] The electrochemical hydrogen permeation method described above is a well-known method for measuring the hydrogen diffusion coefficient in steel, and involves the following measurement steps. The electrochemical hydrogen permeation method using steel by Devanathan et al. is described below. (i) A thin sheet of steel material is used as the specimen 2, and is clamped and fixed between two electrochemical cells 1a and 1b called Devanathan-Stachurski cells. At this time, one side of the specimen is often plated with Pd or Ni. (ii) The Pd- or Ni-plated side of the specimen is the hydrogen detection side, and the non-plated side is the hydrogen introduction side, and the electrochemical cells 1a and 1b are filled with aqueous solutions (electrolytes 7a and 7b). At this time, aqueous solution 7a with high electrical conductivity (e.g., 0.5 M NaCl or 0.1 M NaOH) is used for the hydrogen introduction side, and solution 7b with high electrical conductivity and low corrosiveness (e.g., 0.1 M NaOH for steel materials) is used for the hydrogen detection side.

[0021] (iii) Reference electrodes 3a, 3b and counter electrodes 4a, 4b are placed in the respective electrochemical cells 1a, 1b, and connected to power sources 6a, 6b (generally a potentiostat is used). (iv) At the hydrogen introduction side, a cathodic current or cathodic potential is applied to the specimen 2. This causes electrolysis of water on the specimen 2, and some of the generated hydrogen enters the specimen. (v) On the hydrogen detection side, the specimen 2 is polarized to a potential equal to or higher than the hydrogen generation potential (0 V vs. SHE or higher, generally about 0.2 V vs. SHE). This causes the hydrogen that has diffused from the hydrogen introduction side to be oxidized to hydrogen ions, and the resulting electrons are detected as a current. The residual current after 24 hours of immersion of the specimen 2 can be a negative value depending on the measurement, so it is recommended to use a value of -0.1 μA / cm 2 More than 0.1μA / cm 2 The result is as follows: <Comparative Example> <Electrochemical hydrogen permeation test using pure iron>

[0022] In the comparative example, a thin plate of pure iron was used as the specimen. Both sides of the specimen were wet-polished with SiC waterproof abrasive paper up to #2000, and then ultrasonically cleaned in 2-propanol for 5 minutes. The thickness of the specimen was measured with a micrometer immediately before the electrochemical hydrogen permeation method.

[0023] (Residual current measurement) To compare the residual current when polarized in the solution used on the detection side, only one side of the Devanathan-Stachurski cell shown in Figure 1 was filled with the test solution, and the specimen 2, a thin plate of pure iron, was polarized in each solution. When fixed to the Devanathan-Stachurski cell, O-rings 5a and 5b were used to prevent the test solution from leaking between cells 1a and 1b and specimen 2. The test solutions were 0.1 M NaOH (referred to as NaOH, which corresponds to the conventional method), 2-propanol (purity > 99.7%) to which 1% 0.1 M NaOH was added by volume (referred to as IPA+NaOH), and 2-propanol (referred to as IPA). The reaction area of ​​the specimen was 2 cm2. 2 The electrodes were fixed in electrochemical cells 1a and 1b so that the voltage was +200 mV (vs. SHE) after filling the cells with the test solution. The reference electrodes 3a and 3b were made of Ag / AgCl, and the counter electrodes 4a and 4b were made of Pt wires. The measurement time was 24 hours.

[0024] Figure 2 shows the residual current density of pure iron 24 hours (approximately 86,400 seconds) after the start of polarization. In all test solutions, the residual current decreased over time, and after 24 hours, the residual current was 0.1 μA / cm in all test solutions. 2 It can be seen that the following was achieved. In addition, the residual current value was NaOH>IPA+NaOH>IPA, and it was found that the residual current tended to decrease as the ratio of organic solvent in the solution increased. From the above, it became clear that it is possible to measure the residual current in an organic solvent, and that the use of an organic solvent makes it possible to reduce the residual current in a shorter time.

[0025] (Electrochemical hydrogen permeation test) The thin plate of pure iron was sandwiched between the Devanathan-Stachurski cell and fixed with an O-ring to prevent the test solution from leaking between the cell and the specimen. The reaction area of ​​the specimen was 2 cm2 on both the hydrogen introduction side and the hydrogen detection side. 2This was done. 0.1 M NaOH was used as the solution on the hydrogen-introducing side, and 0.1 M NaOH was used as the aqueous solution on the hydrogen-detecting side for comparison with the conventional method. For both the hydrogen-introducing side and the hydrogen-detecting side, Ag / AgCl was used as the reference electrode, and a Pt wire was used as the counter electrode. First, after filling the hydrogen-detecting side with the test solution, the specimen was polarized at +200 mV (vs. SHE), and after 24 hours, the residual current was 0.1 μA / cm 2 It was confirmed that the following was obtained, and the hydrogen-introducing side was filled with 0.1 M NaOH. Then, hydrogen was generated by applying a current of -1 mA (5 A / m 2 ) to the hydrogen-detecting side, and hydrogen was allowed to penetrate into the specimen. The hydrogen that diffused through the specimen and reached the hydrogen-detecting side was measured as the hydrogen permeation current.

[0026] Fig. 3 shows the hydrogen permeation current density of pure iron when IPA and NaOH were used in the test solution on the hydrogen-detecting side. In any of the solutions, a rise in the current due to hydrogen permeation was observed approximately 200 seconds after the start of the test. Thereafter, the current increased proportionally to the logarithm of time and reached a steady state approximately 20,000 seconds later (about 5 hours and 30 minutes). There were no differences in the current rise time, the slope of the current increase, the time to reach the steady state, or the steady state value due to the difference in the test solution, and it was clarified that the organic solvent could measure the hydrogen permeation current in the same manner as the conventional method.

Example

[0027] <Electrochemical Hydrogen Permeation Test Using Mg-Based Materials> In Example 1, thin plates of pure Mg and AZ31 alloy (Mg - 3Al - 1Zn) were used as the specimens. After wet-polishing both sides of this specimen with SiC waterproof abrasive paper up to #2000, it was ultrasonically cleaned in 2-propanol for 5 minutes. Immediately before the electrochemical hydrogen permeation method, the thickness of the specimen was measured using a micrometer.

[0028] (Residual Current Measurement) To compare the residual current when polarized in the solution used on the detection side, the pure Mg specimen prepared was fixed to a Devanathan-Stachurski cell and polarized in each solution. The test solutions used were 0.1 M NaOH (referred to as NaOH), 2-propanol with 10% 0.1 M NaOH added by volume (referred to as IPA+NaOH (10%)), 2-propanol with 5% 0.1 M NaOH added by volume (referred to as IPA+NaOH (5%)), 2-propanol with 1% 0.1 M NaOH added by volume (referred to as IPA+NaOH (1%)), and 2-propanol (referred to as IPA). The reaction area of ​​the specimen was 2 cm2. 2 The electrode was fixed in an electrochemical cell so that the electrode was in a positive polarity and the cell was filled with the test solution, and then polarized to +200 mV (vs. SHE). Ag / AgCl was used as the reference electrode, and a Pt wire was used as the counter electrode. The measurement time was 24 hours.

[0029] Figure 4 shows the residual current density of pure Mg 24 hours (approximately 86,400 seconds) after the start of polarization. For pure Mg, the residual current tended to decrease with decreasing NaOH aqueous solution content in NaOH, IPA+NaOH (10%), and IPA+NaOH (5%), but the residual current was 0.1 μA / cm 2 The following could not be achieved. In addition, it became clear that the surface of the specimen after the test was severely corroded and could not be used for electrochemical hydrogen permeation testing. On the other hand, the residual current was 0.1 μA / cm for IPA+NaOH (1%) and IPA. 2 The following was achieved, and it became clear that organic solvents with a water content of 1% or less are suitable for electrochemical hydrogen permeation testing of Mg-based materials.

[0030] (Measurement of changes in the specimen surface on the hydrogen introduction side) Since Mg-based materials corrode and thin easily in aqueous solutions, it is necessary to use a solution on the hydrogen inlet side that does not corrode Mg-based materials as much as possible. Using three types of basic solutions that have good electrical conductivity and suppress Mg corrosion, we performed the same experiment as with the electrochemical hydrogen permeation method, with a current of -1 mA (5 A / m 2The surface changes and thickness loss of the specimens were measured when a current of 10 ...

[0031] 5 to 7 show photographs of the specimen surfaces polarized in the respective test solutions and the height differences of the specimen surfaces. FIG. 5 shows the change in the surface of pure Mg on the hydrogen introduction side according to one embodiment of the present invention, where (A) shows the specimen surface when saturated Mg(OH)2 was used, (B) shows the cross-sectional shape at the white dotted line part in (A), and (C) shows an enlarged view of the vertical axis of (B). As shown in Figures 5(A) and (B) for the specimens immersed in Mg(OH)2, slight discoloration was observed on the specimen surface, but there was almost no change, and the height difference measurement did not reveal the formation of corrosion products, thinning, or localized corrosion. Figure 5(C) shows an enlarged view of Figure 5(B). It was found that the unevenness of the specimen was a maximum of about 5 μm, and it remained almost smooth. From the above, a saturated Mg(OH)2 aqueous solution is suitable for the aqueous solution on the hydrogen introduction side for electrochemical hydrogen permeation tests on Mg-based materials.

[0032] Figure 6 shows a comparative example of the present invention, where (A) shows the surface of the specimen when a 0.1M NaOH aqueous solution was used, and (B) shows the cross-sectional shape at the white dotted line part of (A). The height difference of the specimen surface was measured at the white dotted line part of the photograph of the specimen surface. In the specimen immersed in NaOH, the surface of pure Mg was severely corroded (Figure 6(A)), and deep localized corrosion marks were observed in places. Figure 6(B) shows an increase in specimen thickness due to the formation of corrosion products on the specimen surface, a decrease in specimen thickness due to thinning, and localized corrosion reaching a depth of approximately 100 μm to 200 μm. It shows that this method is not applicable to electrochemical hydrogen permeation tests, which require a uniform specimen surface.

[0033] FIG. 7 shows a comparative example of the present invention, where (A) shows the surface of the specimen when a 0.1M MgSO4 aqueous solution is used, and (B) shows the cross-sectional shape of the area surrounded by the white dotted line in (A). Similarly, from Figures 7(A) and (B), the formation of localized corrosion was suppressed even in the specimen immersed in MgSO4, but the thickness of the specimen increased or decreased, making it clear that this method is not applicable to electrochemical hydrogen permeation tests. Mg-based materials are said to exhibit high corrosion resistance in basic solutions, which is due to the formation of a highly corrosion-resistant Mg(OH)2 film on the surface, which is a corrosion product. However, in electrochemical hydrogen permeation tests, the formation of the Mg(OH)2 film causes changes in the thickness of the specimen, and the diffusion coefficient of hydrogen permeating through the film differs from that in the base material, so it is desirable to avoid the formation of the film as much as possible. Therefore, a test solution that suppresses both corrosion and the formation of the film is required on the hydrogen introduction side.

[0034] (Electrochemical hydrogen permeation test) The Devanathan-Stachurski cell shown in Figure 1 was used for the electrochemical hydrogen permeation test. Pure Mg and AZ31 were used as specimens. The prepared specimen was sandwiched between the Devanathan-Stachurski cell and fixed with an O-ring to prevent the test solution from leaking between the cell and the specimen. The reaction area of ​​the specimen was 2 cm2 on both the hydrogen introduction side and the hydrogen detection side. 2 The hydrogen introduction side solution was a saturated Mg(OH)2 aqueous solution, and the hydrogen detection side solution was 2-propanol. Both the hydrogen introduction side and the hydrogen detection side had SSE as the reference electrode and Pt wire as the counter electrode. First, the hydrogen detection side was filled with IPA, and the specimen was polarized at +200 mV (vs. SHE) until the residual current was 0.1 μA / cm 2 After confirming that the hydrogen supply voltage was below -1mA, the hydrogen supply side was filled with saturated Mg(OH)2 aqueous solution. Then, the hydrogen supply side was filled with -1mA (5A / m 2 Hydrogen was generated by passing a current of 1000 kV, which penetrated the specimen. The hydrogen that diffused through the specimen and reached the hydrogen detection side was measured as the hydrogen permeation current.

[0035] Figure 8 shows the hydrogen permeation current density for pure Mg and AZ31. Figure 8(A) shows the hydrogen permeation current density when the horizontal axis is the linear axis representing time, and Figure 8(B) shows the hydrogen permeation current density when the horizontal axis is the logarithmic axis representing time. For pure Mg, a rise in hydrogen permeation current was observed after approximately 50,000 seconds (approximately 14 hours), and for AZ31, a rise in current was observed after approximately 100,000 seconds (approximately 28 hours). For both specimens, the rise in hydrogen permeation current was clearly measured by using IPA on the hydrogen detection side.

[0036] Figure 9 shows the results of continuous measurement of hydrogen permeation current over a long period of time (approximately 3 months) using AZ31 (Figure 9(A) shows the linear axis of time on the horizontal axis, and (B) shows the logarithmic axis of time on the horizontal axis). The hydrogen permeation current from rise to the steady-state value approximately 5 million seconds (approximately 58 days) can be clearly measured. Several methods have been proposed to determine the hydrogen diffusion coefficient from the hydrogen permeation current. Here, the hydrogen diffusion coefficient in AZ31 was determined using the half-rise time method and the breakthrough time method (both of which are described in detail in Non-Patent Document 1).

[0037] Half-rise time method The time t when the hydrogen permeation current becomes half of the steady-state value 1 / 2 is expressed by the following formula: t 1 / 2 =0.14L 2 / D H Here, L is the thickness of the specimen (m), D h is the diffusion coefficient of hydrogen (m 2 / s). As shown in Figure 9(B), t 1 / D H Calculating, D H =4.89×10 -15 m 2 / s was obtained.

[0038] ·Breakthrough time method As shown in FIG. 8(B), if the intersection point of the tangent to the curve drawn by the hydrogen permeation current and the time axis is taken as tb, the following equation is obtained. tb=0.5L 2 / π 2 D H From here D H Calculating, D H =4.56×10 -15 m 2 / s was obtained. From the above results, it is estimated that the hydrogen diffusion coefficient in AZ31 at room temperature is on the order of 10-15 m2 / s. EXAMPLES

[0039] <Electrochemical hydrogen permeation test using pure Al> In Example 2, a thin plate of pure Al (A1050) was used as the specimen. Both sides of the specimen were wet-polished with SiC waterproof abrasive paper up to #2000, and then ultrasonically cleaned in 2-propanol for 5 minutes. The thickness of the specimen was measured using a micrometer immediately before the electrochemical hydrogen permeation method.

[0040] (Electrochemical hydrogen permeation test) For the electrochemical hydrogen permeation test, a Devanathan-Stachurski cell, as shown in Figure 1, was used. The prepared specimen was sandwiched between the Devanathan-Stachurski cell and fixed with an O-ring to prevent the test solution from leaking between the cell and the specimen. The reaction area of ​​the specimen was 2 cm2 on both the hydrogen introduction side and the hydrogen detection side. 2 The solutions used on the hydrogen introduction side were 0.1 M citrate buffer solution (pH 5.1) and 0.1 M borate buffer solution (pH 8.4), and 2-propanol was used as the aqueous solution on the hydrogen detection side. On both the hydrogen introduction side and the hydrogen detection side, Ag / AgCl was used as the reference electrode and a Pt wire was used as the counter electrode. First, the hydrogen detection side was filled with IPA, and then the specimen was polarized at +200 mV (vs. SHE) until the residual current was 0.1 μA / cm 2 After confirming that the hydrogen supply side was below the threshold, the hydrogen supply side was filled with citrate buffer solution or borate buffer solution. Then, -1 mA (5 A / m 2 ) or -10mA (50A / m 2Hydrogen was generated by passing a current of 1000 kV, which penetrated the specimen. The hydrogen that diffused through the specimen and reached the hydrogen detection side was measured as the hydrogen permeation current.

[0041] FIG. 10 shows the hydrogen permeation current density of pure Al when IPA was used as the test solution on the hydrogen detection side, and a citrate buffer solution and a borate buffer solution were used as the test solutions on the hydrogen introduction side. When a current of -1 mA was applied, no rise in hydrogen permeation current was observed until 300,000 seconds (approximately 84 hours) in either the citrate buffer solution or the borate buffer solution. On the other hand, when a current of -10 mA was applied, a rise in current was observed in approximately 50,000 seconds (approximately 14 hours) in the citrate buffer solution and in approximately 150,000 seconds (approximately 42 hours) in the borate buffer solution. In general, the current value on the inlet side affects the amount of hydrogen introduced and the absolute value of the hydrogen permeation current, but does not affect the rise time or general shape of the hydrogen permeation current. However, it is known that the oxide film formed on the surface of pure aluminum prevents hydrogen from entering, and the diffusion rate of hydrogen in the oxide film is also slow. In the case of -1 mA, the surface oxide film was not destroyed, so hydrogen could not be detected within the measurement period, but in the case of -10 mA, the surface oxide film was destroyed, and it is thought that hydrogen that had diffused through pure aluminum could be measured. It is believed that the time required for the oxide film to break down changed because the pH of the citrate buffer solution and the borate buffer solution is different. One reason that the oxide film was broken down when the current on the hydrogen introduction side was large is the drop in pH near the surface. H+ is generated on the Al surface on the hydrogen introduction side due to the electrolysis of water. The larger the current, the more H+ is generated, so it is believed that the pH near the sample surface dropped, destroying the oxide film. This shows that in Al-based materials, the hydrogen permeation current is influenced by the surface oxide film, and that the behavior of the hydrogen permeation current changes depending on the current and solution on the hydrogen introduction side.

[0042] FIG. 11 is a schematic diagram of an electrochemical hydrogen permeation test device (improved Devanathan-Stachurski cell) showing another embodiment of the present invention. The corroding surface of the specimen 2 faces an atmospheric corrosive environment, a steam corrosive environment, or an aqueous corrosive environment 7d, and the specimen 2 is corroded during an electrochemical permeation test. The atmospheric corrosive environment, the steam corrosive environment, or the aqueous corrosive environment 7d may be separated from the external environment by an electrochemical cell 1d. In the case of an atmospheric corrosive environment, the electrochemical cell 1d may not be provided. Corrosion methods include corrosion by droplets, corrosion by immersion in a solution, corrosion by steam, and corrosion by a cyclic corrosion test (CCT). One cycle of the CCT may consist of, for example, dry (50% RH, 5.75 h), wet (98% RH, 1.75 h), and salt spray (0.5% NaCl aqueous solution, 0.5 h) stages, but is not limited thereto. The temperature should be kept at 30° C. throughout the entire CCT. After the CCT, the corroded specimen 2 is subjected to an electrochemical hydrogen permeation test under temperature and humidity control. Preferably, the surface of the corroded sample is observed with a scanning electron microscope (SEM). When a non-ferrous metal material is used for the specimen 2, a water-soluble organic solvent is preferably used as the aqueous solution (electrolyte 7c) filling the electrolytic cell 1c. At least one of ethanol, methanol, 2-propanol, and ethylene glycol is preferably used as the water-soluble organic solvent, and the amount of the aqueous solution is preferably 0.01% or more and 50% or less, but the water-soluble organic solvent is not limited to these.

[0043] In the electrochemical permeation test of the specimen 2, one side of the specimen 2 has a corroded surface and is open to the atmosphere. One side of the specimen 2 is in contact with the electrolytic cell 1c. In the electrolytic cell 1c, the specimen 2 is polarized at a constant potential anode to oxidize hydrogen that has permeated the specimen 2 to hydrogen ions, and the amount of hydrogen that has permeated is determined from the current value. In the figure, 3c is a reference electrode, 4c is an electrode, and 4c is called a counter electrode or a coefficient electrode. The electrode 4c is connected to a power source 6c, which is a potentiostat that applies a constant potential. 5c is an O-ring that brings the specimen 2 and the electrolytic cell 1c into close contact with each other to prevent leakage of the test solution.

[0044] Using the electrochemical hydrogen permeation test apparatus configured in this way, an experiment can be carried out as follows. A specimen 2 with one side corroded is fixed to a modified Devanathan cell. Next, the sample surface on the hydrogen extraction side is faced toward the organic solvent in a cell (electrolytic cell) 1c, and an Ag / AgCl reference electrode and a Pt counter electrode are placed in the electrolytic cell 1c. The electrolytic cell 1c is placed in a thermo-hygrostat (not shown), and the specimen 2 and the electrodes 3c and 4c are connected to the corresponding terminals R, C, and W of a potentiostat 6c through ports in the thermo-hygrostat. The hydrogen extraction side is polarized at +200 mV, and the hydrogen permeation current is recorded every 5 seconds by a data logger (not shown). Prior to the permeation test, the passive current density, which serves as the background for the hydrogen permeation current, is set to 0.1 μA / cm 2 The temperature in the thermo-hygrostat should be kept at 30°C, and the relative humidity should be increased stepwise, for example, in the order of 50, 70, 80, and 98% RH, but is not limited to this. Each humidity level of 50-70% RH should be maintained for about 2 hours. After increasing to 98% RH, the humidity should be maintained at that level for 10 hours, and then the relative humidity should be decreased stepwise.

[0045] In the embodiment shown in FIG. 11, one surface of the specimen 2 is a corroding surface and is open to the atmosphere, but the present invention is not limited to this. One surface of the specimen 2 may be a corroding surface and may be a surface that is in a water vapor corrosive environment, or a surface that is in an aqueous solution corrosive environment at a potential at which electrolysis of water occurs. [Industrial Applicability]

[0046] As described above in detail, the method of measuring the amount of hydrogen that has penetrated into a metal according to the present invention can reduce the residual current on the hydrogen detection side, and measures the amount of hydrogen that has penetrated into a non-ferrous metal material using a test solution that is optimal for the non-ferrous metal material. Therefore, it is possible to measure the hydrogen diffusion coefficient in the actual usage environment (i.e., hydrogen that penetrates due to corrosion) with small error, and has great practical benefits. [Explanation of symbols]

[0047] 1a, 1b, 1c Electrolyzer (electrochemical cell) 1d Atmospheric corrosive environment, steam corrosive environment, or aqueous corrosive environment 2 Metal sample (specimen) 3a, 3b, 3 reference electrodes 4a, 4b, 4 Opposite 5a, 5b O-ring 6a, 6b, 6 Power supply (potentiostat) 7a, 7b, 7c Electrolyte

Claims

1. A method for measuring the amount of hydrogen that penetrates into a metal during corrosion of a specimen made of a non-ferrous metal material, using an electrochemical hydrogen permeation method, wherein when one surface of the specimen is a surface where hydrogen penetrates at a potential at which electrolysis of water occurs, and the other surface is a hydrogen detection surface controlled to a potential or current at which hydrogen atoms are oxidized to hydrogen ions, A first electrochemical cell is provided on the side where hydrogen enters, and an aqueous solution having an electrical conductivity of 1 μS / cm or more and 2 × 10 ５ μS / cm or less at 25°C is filled inside the first electrochemical cell, and a first reference electrode and a first counter electrode are installed, a second electrochemical cell is provided on the side of the hydrogen detection surface, and the inside of the second electrochemical cell is filled with an organic solvent soluble in water and an aqueous solution in which 0.01% or more and 50% or less of the above organic solvent is dissolved, and a second reference electrode and a second counter electrode are installed, In the first electrochemical cell, a first power supply is connected to the first reference electrode and the first counter electrode. When the first power supply is under potential control, a potential higher than -10 V and lower than the immersion potential of the test specimen is applied. When the first power supply is under current control, a constant current of ２ not less than -0.01 mA / cm ２ and not more than -100 mA / cm is applied. in the second electrochemical cell, a second power source is connected to the second reference electrode and the second counter electrode, and the second power source applies a potential of 0 V or more and 1 V or less with respect to the standard hydrogen electrode, The residual current after 24 hours of immersion of the test specimen is -0.1 μA / cm ２ or more and 0.1 μA / cm ２ A method for measuring the amount of hydrogen penetrating into a non-ferrous metal material, characterized in that it is as follows.

2. The non-ferrous metal material is beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), zinc (Zn), yttrium (Y), zirconium (Zr), or an alloy containing 50 atomic% or more of these non-ferrous metal elements, and is a non-ferrous metal element or alloy having a standard electrode potential lower than that of iron (Fe). The method for measuring the amount of hydrogen penetrating into the non-ferrous metal material according to claim 1.

3. The non-ferrous metal material is an Al-based metal material, and the aqueous solution filled in the first electrochemical cell is a citric acid buffer solution (pH 5 - 9) or a boric acid buffer solution (pH 5 - 9). The method for measuring the amount of hydrogen penetrating into the non-ferrous metal material according to claim 1 or 2. The method for measuring the amount of hydrogen penetrating into the non-ferrous metal material according to claim 1 or 2.

4. The non-ferrous metal material is an Mg-based metal material, The aqueous solution filled in the first electrochemical cell is 0.001 M to saturated NaOH aqueous solution, 0.001 M to saturated MgSO ４ aqueous solution, or 0.001 M to saturated Mg(OH) ２ aqueous solution, The method for measuring the amount of hydrogen penetrating into the non-ferrous metal material according to claim 1 or 2.

5. The organic solvent soluble in water is at least one of ethanol, methanol, 2-propanol, and ethylene glycol, and the amount of the aqueous solution is 0.01% or more and 50% or less. The method for measuring the amount of hydrogen penetrating into the non-ferrous metal material according to claim 1.

6. An apparatus for measuring the amount of hydrogen that penetrates into a metal during corrosion of a specimen made of a non-ferrous metal material, using an electrochemical hydrogen permeation method, wherein when one surface of the specimen is a surface where hydrogen penetrates at a potential at which electrolysis of water occurs, and the other surface is a hydrogen detection surface controlled to a potential or current at which hydrogen atoms are oxidized to hydrogen ions, A first electrochemical cell provided on the hydrogen intrusion surface side and having a first reference electrode and a first counter electrode immersed in a first electrolyte solution; A second electrochemical cell provided on the hydrogen detection surface side and having a second reference electrode and a second counter electrode immersed in a second electrolyte solution; Comprising; The first electrolyte has an electrical conductivity of 1 μS / cm or more and 2×10 ５ μS / cm or less at 25°C and is an aqueous solution filled inside the first electrochemical cell, The second electrolyte solution is obtained by dissolving water in a water-soluble organic solvent and an aqueous solution of 0.01% or more and 50% or less in the organic solvent, and is filled inside the second electrochemical cell. In the first electrochemical cell, a first power source is connected to the first reference electrode and the first counter electrode. When the first power source is under potential control, a potential higher than -10 V and lower than the immersion potential of the specimen is applied. When the first power source is under current control, a constant current of ２ not less than -0.01 mA / cm ２ and not more than -100 mA / cm is applied. In the second electrochemical cell, a second power source is connected to the second reference electrode and the second counter electrode, and the second power source applies a potential of 0 V or more and 1 V or less with respect to the standard hydrogen electrode. The residual current after 24 hours of immersion of the specimen is -0.1 μA / cm ２ or more and 0.1 μA / cm ２ The measuring device for the amount of hydrogen infiltrated into the non-ferrous metal material is characterized in that it is as follows.

7. A method for measuring the amount of hydrogen that penetrates into a metal during corrosion of a specimen made of a non-ferrous metal material using an electrochemical hydrogen permeation method, When one surface of the specimen is a corrosion surface and the other surface is a hydrogen detection surface controlled to a potential at which hydrogen atoms are oxidized to hydrogen ions, The corrosion surface is any one of a surface open to the atmosphere, a surface in a water vapor environment, or a surface in an aqueous solution corrosion environment. An electrochemical cell is provided on the hydrogen detection surface side, and the inside of the electrochemical cell is filled with a water-soluble organic solvent and an aqueous solution of 0.01% or more and 50% or less dissolved in the organic solvent, and a reference electrode and a counter electrode are installed. In the electrochemical cell, a power source is connected to the reference electrode and the counter electrode, and the power source applies a potential of 0 V or more and 1 V or less with respect to the standard hydrogen electrode. The residual current after 24 hours of immersion of the specimen is -0.1 μA / cm ２ or more and 0.1 μA / cm ２ A method for measuring the amount of hydrogen intrusion into a non-ferrous metal material, characterized in that it is as follows.

8. The non-ferrous metal material according to claim 7, wherein the non-ferrous metal material is beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), zinc (Zn), yttrium (Y), zirconium (Zr), or an alloy containing 50 atomic% or more of these non-ferrous metal elements, and is a non-ferrous metal element or alloy having a lower standard electrode potential than iron (Fe). Method for measuring the amount of hydrogen penetrating into the non-ferrous metal material.

9. The water-soluble organic solvent is at least one of ethanol, methanol, 2-propanol, and ethylene glycol, The method for measuring the amount of hydrogen penetrating into the non-ferrous metal material according to claim 7 or 8, wherein the amount of the aqueous solution is 0.01% or more and 50% or less.

10. An apparatus for measuring the amount of hydrogen that penetrates into a metal during the corrosion of a specimen made of a non-ferrous metal material using an electrochemical hydrogen permeation method, when one surface of the specimen is a corrosion surface and the other surface is a hydrogen detection surface controlled to a potential at which hydrogen atoms are oxidized to hydrogen ions, an environment open to the atmosphere, a water vapor environment, or an aqueous solution corrosion environment provided on the corrosion surface side, an electrochemical cell provided on the hydrogen detection surface side and installed with a reference electrode and a counter electrode immersed in a third electrolyte, comprises, the third electrolyte is a water-soluble organic solvent and an aqueous solution of 0.01% or more and 50% or less dissolved in the organic solvent, and is filled inside the electrochemical cell, in the electrochemical cell, a power source is connected to the reference electrode and the counter electrode, and the power source applies a potential of 0 V or more and 1 V or less with respect to the standard hydrogen electrode, The residual current after 24 hours of immersion of the specimen is -0.1 μA / cm ２ or more and 0.1 μA / cm ２ A measuring device for the amount of hydrogen that has penetrated into a non-ferrous metal material, characterized in that it is as follows

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