JP2017207302A - Intrusion hydrogen amount measurement method and intrusion hydrogen amount measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intrusion hydrogen amount measurement method which can exactly and continuously measure an intrusion hydrogen amount by removing an influence of a passive state holding current even in a corrosive atmosphere in which a temperature is changed.SOLUTION: In an intrusion hydrogen amount measurement method, one face of a specimen composed of a metal material is exposed to a corrosive atmosphere, and set as a hydrogen intrusion face, the other face of the specimen is set as a hydrogen detection face having a plated film, anode current density: iis measured by using an electrochemical cell which is installed on the hydrogen detection face, a temperature: T of a test atmosphere is measured, passive state holding current density: iis calculated from the temperature: T of the test atmosphere on the basis of a relationship between the pre-acquired passive state holding current density: i, and the temperature: T of the test atmosphere which are expressed by the following formula (1), hydrogen permeation current density: iis acquired by subtracting the passive state holding current density: ifrom the anode current density: i, and an intrusion hydrogen amount is calculated. i=A×e...(1).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for measuring the amount of intrusion hydrogen that measures the amount of hydrogen penetrating into a metal due to corrosion (the amount of intrusion hydrogen) by an electrochemical hydrogen permeation method. The present invention relates to a method for measuring the amount of penetrating hydrogen that can accurately measure the amount of penetrating hydrogen by removing the influence of the passive state holding current as a background that varies with temperature. The present invention also relates to an intrusion hydrogen amount measuring apparatus for carrying out the intrusion hydrogen amount measurement method.

  In recent years, the use of high-strength steel has been expanded in all fields from the viewpoint of saving resources and energy. However, it is known that the use of high-strength steel has an adverse effect, and the risk of hydrogen embrittlement increases as the material strength increases (Non-Patent Document 1). In particular, in the automobile field, ultra high strength steel sheets having a tensile strength of 1180 MPa class have begun to be used, and there is a concern that such steel sheets may cause hydrogen embrittlement even in an atmospheric environment. In the atmospheric environment, hydrogen penetrates into the steel with a corrosion reaction, and the amount of invading hydrogen also changes due to changes in environmental factors such as temperature, humidity, and salinity. Therefore, in order to grasp the hydrogen intrusion behavior in the atmospheric environment, a technique for continuously monitoring the amount of intrusion hydrogen is desired.

  Non-Patent Document 2 discloses that, based on an electrochemical hydrogen permeation method, one side of a metal that is a test piece is exposed to an atmospheric corrosion environment, and hydrogen that has penetrated into and permeated through the steel is detected on the opposite side of the test piece. The results of monitoring the anode current on the surface have been reported. Here, the anode current measured by the electrochemical hydrogen permeation method includes the hydrogen permeation current measured when ionizing hydrogen atoms that have permeated through the steel at the detection surface, and a passive state as a background. Holding current is included. This passive state holding current is known to depend on temperature (Non-Patent Document 3), but in the method described in Non-Patent Document 2, this temperature dependency is not taken into consideration, so that hydrogen intrusion occurs. The amount cannot be accurately estimated.

  Therefore, Patent Document 1 proposes a method for correcting the influence of the passive state holding current in the measurement of the intrusion hydrogen amount by the electrochemical hydrogen permeation method. Specifically, two or more measurement cells are installed for the same test piece, and a protective film is provided on the hydrogen entry surface of one measurement cell to prevent hydrogen from entering, thereby measuring the passive state holding current. By subtracting the passive state holding current measured in the reference cell from the anode current measured in the normal measurement cell as the reference cell, the influence of the passive state holding current that varies with temperature is removed.

JP 2014-89207 A

Matsuyama Junsaku, "Delayed Destruction", Nikkan Kogyo Shimbun, 1989 Omura et al., Iron and Steel, 2005, Vol. 91, no. 5, p. 478-484 Toshio Shibata, Materials and Environment, 2011, Vol. 60, p. 374-379 Muto et al., Materials and Environment, 1998, Vol. 47, p. 519-527 Takahiro Kushida, Materials and Environment, 2000, Vol. 49, p. 195-200

  According to the method described in Patent Document 1, it is possible to improve the measurement accuracy of the intrusion hydrogen amount. However, as a result of the study by the present inventors, even in the same test piece, the passive state holding current differs depending on the position, and as a result, it may be difficult to correct the background by the method described in Patent Document 1. I understood that.

  The present invention has been made in view of such circumstances, and intrusion hydrogen that can accurately and continuously measure the amount of intrusion hydrogen even in a corrosive environment where the temperature changes, by removing the influence of the passive state holding current. It is an object of the present invention to provide a quantity measuring method and a measuring apparatus therefor.

  As a result of intensive studies to achieve the above object, the present inventors formulate the temperature dependence of the passive state holding current, which is the background current, in advance, and uses the above formula in the measurement. It was found that the amount of penetrating hydrogen can be measured accurately even in an environment where the temperature fluctuates by calculating and correcting the passive state holding current value from the temperature of the test environment.

This invention is made | formed based on the said knowledge, The summary structure is as follows.
1. In a corrosive environment where the temperature changes, an intrusion hydrogen amount measurement method that measures the amount of hydrogen penetrating into the metal by corrosion using an electrochemical hydrogen permeation method,
One side of a test piece made of a metal material is exposed to a corrosive environment to form a hydrogen intrusion surface,
The other surface of the test piece is a hydrogen detection surface provided with a plating film,
Electrochemical cell anode current density installed in the hydrogen detecting surface: measuring the i _a,
Measure the temperature of the test environment: T
Previously determined, passive holding current density is expressed by the following equation (1): i _p and temperature of the test environment: Based on the relationship between T, the measured temperature of the said test environment: from T passive holding current density: to calculate the i _p,
The anode current density from said i _a passive holding current density by subtracting i _p, the hydrogen permeation current density: seeking i _H,
The hydrogen permeation current density: a method for measuring an intrusion hydrogen amount, wherein the intrusion hydrogen amount is calculated from i _H.
I _p = A × e− ^{B / T} (1)
(Here, A and B are constants depending on the properties of the plating film)

2. 2. The method for measuring an intrusion hydrogen amount according to 1 above, wherein the temperature of the test piece is measured as T of the test environment.

3. 3. The method for measuring the amount of invading hydrogen according to 1 or 2 above, wherein the corrosive environment is an outdoor exposure environment that is exposed to direct sunlight.

4). An intrusion hydrogen amount measuring apparatus for carrying out the intrusion hydrogen amount measurement method described in 2 above,
An electrochemical cell installed on the hydrogen detection surface of the test piece;
Temperature measuring means for measuring the temperature of the test piece;
Control means connected to the electrochemical cell and the temperature measuring means;
The control means is
It was measured for T simultaneously: the measurement of i _a, the temperature measuring means due to the test piece temperature: anode current density due to the electrochemical cell
Previously determined (1) of the test piece was measured based on a relationship type temperature: T from passive holding current density: calculating a i _p,
The anode current density from said i _a passive holding current density by subtracting i _p, the hydrogen permeation current density: seeking i _H,
An intrusion hydrogen amount measuring apparatus configured to calculate an intrusion hydrogen amount from the hydrogen permeation current density: i _H.

  According to the present invention, even in a corrosive environment where the temperature changes, it is possible to accurately and continuously measure the amount of invading hydrogen by removing the influence of the passive state holding current.

It is a schematic diagram which shows the intrusion hydrogen amount measuring apparatus in one Embodiment of this invention. It is a graph which shows the temperature dependence of the passive state holding current in a measurement cell and a reference cell. It is a graph which shows the time-dependent change of the anode current and test piece temperature in a measurement cell and a reference cell. It is a graph which shows the time-dependent change of the hydrogen permeation current density obtained by the method of the Example and the comparative example.

  In the method for measuring the amount of intrusion hydrogen that is one embodiment of the present invention, the amount of hydrogen that penetrates into the metal due to corrosion is measured by an electrochemical hydrogen permeation method. At that time, the hydrogen permeation flux in the test specimen was measured in a state where one surface of the test piece made of a metal material was exposed to a corrosive environment to be a hydrogen intrusion surface and the other surface of the test piece was a hydrogen detection surface. The anode current density is measured using an electrochemical cell installed on the hydrogen detection surface.

The anode current density: The i _a, the hydrogen permeation current density is ionization current of the hydrogen atoms has been transmitted through the test piece: In addition to i _H, background current at some passivation holding current density includes i _p The passive state holding current density depends on temperature (Non-patent Document 3). Therefore, in order to accurately measure the hydrogen permeation current in an environment where the temperature fluctuates, it is necessary to perform background correction in consideration of the temperature change of the passive state holding current.

  In Patent Document 1, a normal measurement cell and a reference cell are provided on the same test piece, and correction is performed by subtracting the passive state holding current measured in the reference cell from the anode current measured in the measurement cell. Has been proposed. However, as described above, it was found that, even with the same test piece, the passive state holding current differs depending on the position, and therefore it may be difficult to correct the background by the above method.

  Here, the hydrogen detection surface of a test piece used in the electrochemical hydrogen permeation method is generally coated with a plating film such as Ni, Pd, or an alloy thereof. Even on the surface, it is difficult to form a plating film uniformly, and therefore there is a difference in the properties of the plating film depending on the position on the surface of the test piece. This difference in the properties of the plating film is considered to affect the temperature dependence of the passive state holding current.

  Therefore, in the present invention, the temperature dependence of the passive state holding current is measured in advance and converted into a formula, and the background correction at the time of measurement is performed using the formula. This makes it possible to perform correction based on the temperature measurement result of the test environment without separately providing a reference cell for measurement.

Hereinafter, the correction method in the present invention will be specifically described.
Passive holding current density: i _p denotes a linear relationship that logarithm is against the reciprocal of temperature, it is known to satisfy the Arrhenius equation. Therefore, first, in an environment where hydrogen does not enter, that is, in an environment where the test piece does not corrode, the temperature of the test environment is changed to measure the passive state holding current density. Formula as a function of.
i _p = A × e ^{−B / T} (1)
Here, A and B in the formula (1) are constants depending on the properties of the plating film, and T is the absolute temperature (K) of the test environment.

  Here, the above mathematical expression, that is, determination of A and B can be performed in any environment as long as the test piece does not corrode. An example of an environment where the test piece does not corrode is a low humidity environment where no salt adheres to the hydrogen entry surface. In this case, the humidity is preferably 30% RH or less. Moreover, it can replace with low humidity and can also provide the protective film which prevents the corrosion of this test piece in the hydrogen penetration | invasion surface of a test piece. The protective film is preferably one that can be peeled off without changing the surface state of the hydrogen entry surface of the test piece. As the protective film, for example, a protective film made of a resin can be used, and as the resin, an epoxy resin paint or the like can be used.

In the actual measurement of the hydrogen intrusion amount, the temperature of the test environment: T is measured, and the obtained temperature of the test environment: T and the above equation (1), the passive state holding current density at the temperature: i _The net hydrogen permeation current density: i _H can be obtained by calculating _p and subtracting the passive state current density: i _p from the anode current density: i _a measured by the electrochemical hydrogen permeation method ( (Formula (2) below). Note that the units of i _H , i _a , and i _p are not particularly limited. If they are the same unit, the calculation of formula (2) can be established, and can be, for example, A / cm ² .
i _H = i _a −i _p (2)

  As the temperature of the test environment, the temperature of the environment where the test piece is placed can be used. However, for example, when measuring the amount of invading hydrogen in an outdoor exposure environment, the temperature of the test environment and the temperature of the test piece may be different due to the influence of direct sunlight, radiant cooling, or the like (Non-Patent Document 4). Therefore, the hydrogen permeation current density can be measured more accurately by measuring the temperature of the test piece as the temperature of the test environment.

The amount of penetrating hydrogen can be calculated from the hydrogen permeation current density obtained as described above. Here, the amount of penetrating hydrogen in the electrochemical hydrogen permeation method is calculated as surface hydrogen concentration (adsorbed hydrogen concentration on the hydrogen penetrating surface): C _ab , and calculated by the following formula (3) using hydrogen permeation current: i _H. Is done.
C _ab = (i _H × L × M _H ) / (D × F × d) × 10 ⁶ (3)
C _ab : Surface hydrogen concentration (mass ppm)
i _H : Hydrogen permeation current density (A / cm ² )
L: Thickness of the test piece (cm)
D: Hydrogen diffusion coefficient in the metal material of the test piece (cm ² / s)
F: Faraday constant (C / mol)
M _H : molar mass of hydrogen atom (g / mol)
d: Density of the metal material of the test piece (g / cm ³ )

  In an environment where the temperature changes, the hydrogen diffusion coefficient D in the material changes. Like the passive state holding current, the hydrogen diffusion coefficient is known to satisfy the Arrhenius equation in which the logarithmic value shows a linear relationship with the reciprocal of temperature. By using the apparatus of the present invention, hydrogen diffusion is performed in advance. By formulating the temperature dependence of the coefficient, it is possible to calculate the temperature change of the hydrogen diffusion coefficient from the material temperature of the specimen and to calculate the amount of intrusion hydrogen more accurately.

  As described above, according to the present invention, even in a corrosive environment where the temperature changes, it is possible to accurately and continuously measure the amount of intrusion hydrogen without removing the influence of the passive state holding current without separately providing a reference cell. it can. Therefore, it is possible to accurately measure the amount of invading hydrogen that changes every moment in a corrosive environment.

  Next, the intrusion hydrogen amount measuring apparatus of the present invention will be described. The intrusion hydrogen amount measuring device of the present invention is connected to an electrochemical cell installed on a hydrogen detection surface of a test piece, a temperature measuring means for measuring the temperature of the test piece, the electrochemical cell and the temperature measuring means. Control means.

  FIG. 1 is a schematic diagram showing an intrusion hydrogen amount measuring apparatus 1 according to an embodiment of the present invention. One surface of the test piece 10 is exposed to a corrosive environment to be a hydrogen intrusion surface 11, and the other surface of the test piece is a hydrogen detection surface 12. The hydrogen detection surface 12 is provided with a plating film (not shown). The hydrogen detection surface 12 is provided with an electrochemical cell 20 for measuring the anode current.

  As the test piece 10, an arbitrary one made of a metal material can be used, but in the example shown in FIG. 1, a plate-shaped steel plate is used. The thickness of the test piece 10 is not particularly limited, and can be an arbitrary thickness. However, if the specimen is too thick, the time lag between changes in the corrosive environment and changes in the measured hydrogen permeation current increases, resulting in an unclear relationship between environmental factors and the amount of intrusion hydrogen. It may become. Therefore, it is better to reduce the plate thickness especially when the hydrogen diffusion coefficient of the material constituting the test piece is small. In addition, if the hydrogen diffusion in the material is unsteady, it is better that the plate thickness is thinner in that accurate surface hydrogen concentration cannot be calculated. Specifically, the thickness of the test piece is preferably 1 mm or less, and more preferably 0.5 mm or less. On the other hand, if the test piece is excessively thin, perforation due to corrosion occurs in a short period of time. Therefore, the thickness of the test piece is preferably 0.2 mm or more.

  As the electrochemical cell 20, any cell can be used as long as it can measure the anode current on the hydrogen detection surface 12. In the example shown in FIG. 1, the electrochemical cell 20 includes an electrolytic solution 21, a containing body 22 that contains the electrolytic solution 21, a reference electrode 23 installed inside the containing body 21, and a counter electrode 24. ing.

  As the electrolyte solution 21, any electrolyte solution can be used as long as it can measure the anode current. Usually, an electrolyte aqueous solution is used. In addition, if the pH of the electrolytic solution 21 is less than 9, it may be difficult to maintain a passive state on the hydrogen detection surface 12 when measuring the anode current. Therefore, the pH of the electrolytic solution 21 may be 9 or more. preferable. On the other hand, if the pH is excessively high, that is, if it is strongly alkaline, the electrolyte solution may have a pH of 13 or less because damage to the environment or the like is great when the electrolyte solution leaks to the outside due to an accident. preferable. Examples of the electrolytic solution that satisfies the above conditions and can be suitably used include an aqueous NaOH solution of about 0.1 to 1.0 M (M = mol / L). From the viewpoint of preventing leakage of the electrolytic solution and ease of handling, it is also preferable to use a gel electrolyte instead of the liquid electrolyte solution.

  Any container 22 can be used as long as it can accommodate the electrolytic solution 21 and the like. Usually, a container made of insulating glass or resin is used. In particular, from the viewpoint of workability and ease of handling, it is preferably made of resin, more preferably made of acrylic resin.

  The reference electrode 23 is an electrode that serves as a potential reference when measuring the anode current in the electrochemical cell 20 and is also referred to as a reference electrode. The reference electrode 23 is not particularly limited, and various electrodes currently in practical use such as those used for general electrochemical measurements can be used. Examples of reference electrodes that can be suitably used include silver-silver chloride electrodes (SSE). As the aqueous electrolyte solution used for the silver-silver chloride electrode, for example, saturated KCl or the like can be used.

  As the counter electrode 24, any inert electrode can be used as long as it can measure the anode current and does not inhibit the ionization reaction of hydrogen atoms on the hydrogen detection surface 12. An example of a counter electrode that can be suitably used is a platinum (Pt) electrode.

  The reference electrode 23 and the counter electrode 24 are connected to the potentiostat 30. Further, the test piece 10 is also connected to the potentiostat 30 and serves as a working electrode when measuring the anode current.

  Furthermore, in the example shown in FIG. 1, a thermocouple 40 as a temperature measuring means for measuring the temperature of the test piece 10 is installed so as to be in contact with the test piece 10. As the thermocouple 40, arbitrary things, such as a general thermocouple represented by alumel-chromel (K thermocouple), can be used. The method of installing the thermocouple is not particularly limited, but it is preferable to cover a portion where the test piece and the thermocouple are in contact from the viewpoint of preventing the contact corrosion of different metals between the test piece and the thermocouple.

Incidentally, absorbed hydrogen amount measuring apparatus of the present invention is provided with a control means, anode current density by the electrochemical cell: the measurement of i _a, the temperature measuring means due to the test piece temperature: the T perform measurements simultaneously, previously obtained (1) of the test piece was measured based on a relationship type temperature: T from passive holding current density i _p is calculated, and the anode current density from said i _a by subtracting the i _p, the hydrogen permeation current density: passive holding current density seek i _H, the hydrogen permeation current density is from i _H is configured to calculate the absorbed hydrogen amount. In the example shown in FIG. 1, the potentiostat 30 and the temperature logger 50 can also be regarded as a part of the control means.

  In addition, the measurement conditions in the present invention may be any combination of a solution and a potential that can maintain the passivation of the surface of the steel material when held at a potential sufficient for the hydrogen ionization reaction on the hydrogen detection surface, and are particularly limited. It is not a thing. In general, in a 1N NaOH aqueous solution, −0.1 to 0.3 V vs. SCE polarization conditions are widely used (Non-Patent Document 3). Here, SCE is a saturated calomel electrode, and the potential of this SCE with respect to a standard hydrogen electrode (SHE) is represented by +0.244 V (vs SHE, 25 ° C.). Moreover, when SSE is used, it can measure at 0V (nonpatent literature 5).

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

(Example)
A mild steel plate having a thickness of 1 mm was used as a test piece, and the amount of intrusion hydrogen was measured under the conditions described below using the apparatus having the configuration shown in FIG. The hydrogen detection surface of the test piece was subjected to Pd plating with a thickness of about 100 nm. As the electrolytic solution, 1N NaOH was used, and 0 V vs. Anodically polarized under SSE conditions.

(Comparative example)
For comparison, a reference cell for background correction is arranged on the hydrogen detection surface of the same test piece as that of the above-mentioned example by simulating the method of Patent Document 1, and corresponds to the reference cell on the hydrogen intrusion surface. The position to be covered was covered with a protective film. Hereinafter, the electrochemical cell in the above example is referred to as “measurement cell”, and the electrochemical cell in the comparative example is referred to as “reference cell”. The measurement conditions in the reference cell were the same as those in the measurement cell except that the protective film was provided as described above.

[Temperature dependence of passive state holding current density]
Prior to the measurement of the intrusion hydrogen amount, the temperature dependence of the passive state holding current density in the measurement cell and the reference cell was evaluated.

  In order to measure the passive state holding current density, it is necessary to measure the current in a state where hydrogen does not enter the hydrogen intrusion surface. The hydrogen intrusion surface of the reference cell is covered with a protective film, but there is no protective film on the hydrogen intrusion surface of the measurement cell. It is necessary to prevent corrosion from occurring in Therefore, the current was measured in a low humidity environment (30% RH) without salt adhesion on the hydrogen entry surface of the test piece. Since the current measured in this state does not include the hydrogen permeation current in either the measurement cell or the reference cell, it can be regarded as a passive state holding current.

FIG. 2 is a graph showing the temperature dependence of the passive state holding current in the measurement cell and the reference cell measured by the above method. Here, the passive holding current was measured by changing the temperature of the test piece to 20, 30, 40, and 50 ° C. FIG. 2 shows that there is a linear relationship between the logarithmic value of the passive holding current density and the inverse of the temperature, and the Arrhenius equation is established. From the above results, the temperature dependence of the passive holding current density in the measurement cell and the reference cell is expressed as follows.
Measurement cell: i _p (nA / cm ² ) = 1.124 × 10 ¹³ × exp (−8.038 × 10 ³ / T) (4)
Reference cell: i _p (nA / cm ² ) = 2.455 × 10 ¹³ × exp (-8.164 × 10 ³ / T) (5)
In addition, when the passive holding current density at each temperature is compared between the reference cell and the measuring cell, the passive holding current value density of the reference cell is larger than that of the measuring cell, and even if the measurement location is different in the same specimen, It can be seen that the holding current density is different.

[Measurement of hydrogen permeation current density]
Next, the test piece was exposed to an outdoor environment, and the anode current and the temperature of the test piece were measured simultaneously. FIG. 3 is a graph showing temporal changes in anode current density and test piece temperature in the measurement cell and the reference cell. From the measurement results, it can be seen that the anode current density fluctuates under the influence of the temperature change in both the reference cell and the measurement cell.

  Here, in accordance with the method of Patent Document 1, the result of subtracting the current density in the reference cell from the anode current density measured in the measurement cell in order to remove the passive holding current that is the background current is shown in FIG. Shown as a comparative example (broken line). In the comparative example, the hydrogen permeation current value density shows a negative value in most of the measurement period. This is considered to be a result of excessive removal of the background current because the passive holding current is different between the measurement cell and the reference cell. Therefore, even if it is the same test body, when the temperature dependence of a passive holding current changes with locations to measure, it turns out that temperature correction by the method proposed by patent documents 1 is difficult.

  On the other hand, the passive holding current density is calculated from the above equation (4) representing the temperature dependence of the passive holding current density in the measurement cell and the measured value of the test piece temperature shown in FIG. FIG. 4 shows the results of obtaining the hydrogen permeation current density by subtracting the current density from the anode current density in the measurement cell shown by the solid line in FIG. 3 as an example of the present invention (solid line). From the results shown in FIG. 4, it can be seen that according to the present invention, even in a corrosive environment where the temperature changes, the intrusion hydrogen amount can be accurately and continuously evaluated by removing the influence of the passive state holding current.

  Thus, according to the present invention, in a corrosive environment where the temperature fluctuates, the amount of hydrogen entering the metal material can be continuously measured with high accuracy. Therefore, by using the present invention, it is possible to accurately grasp the correlation between environmental factors and the amount of invading hydrogen, which is extremely effective in determining whether or not metallic materials such as ultra-high strength steel can be applied to the atmospheric environment. is there.

DESCRIPTION OF SYMBOLS 1 Intrusion hydrogen amount measuring apparatus 10 Test piece 11 Hydrogen penetration surface 12 Hydrogen detection surface 20 Electrochemical cell 21 Electrolytic solution 22 Container 23 Reference electrode 24 Counter electrode 30 Potentiostat 40 Thermocouple (Temperature measurement means)
50 temperature logger

Claims (4)

In a corrosive environment where the temperature changes, an intrusion hydrogen amount measurement method that measures the amount of hydrogen penetrating into the metal by corrosion using an electrochemical hydrogen permeation method,
One side of a test piece made of a metal material is exposed to a corrosive environment to form a hydrogen intrusion surface,
The other surface of the test piece is a hydrogen detection surface provided with a plating film,
Electrochemical cell anode current density installed in the hydrogen detecting surface: measuring the i _a,
Measure the temperature of the test environment: T
Previously determined, passive holding current density is expressed by the following equation (1): i _p and temperature of the test environment: Based on the relationship between T (K), of said measured test environment temperature: not from T働態holding current density: calculating a i _p,
The anode current density from said i _a passive holding current density by subtracting i _p, the hydrogen permeation current density: seeking i _H,
The hydrogen permeation current density: a method for measuring an intrusion hydrogen amount, wherein the intrusion hydrogen amount is calculated from i _H.
I _p = A × e− ^{B / T} (1)
(Here, A and B are constants depending on the properties of the plating film)   The method for measuring an intrusion hydrogen amount according to claim 1, wherein the temperature of the test piece is measured as a temperature T of the test environment.   The method for measuring the amount of invading hydrogen according to claim 1 or 2, wherein the corrosive environment is an outdoor exposure environment that is exposed to direct sunlight. An intrusion hydrogen amount measuring apparatus for carrying out the intrusion hydrogen amount measurement method according to claim 2,
An electrochemical cell installed on the hydrogen detection surface of the test piece;
Temperature measuring means for measuring the temperature of the test piece;
Control means connected to the electrochemical cell and the temperature measuring means;
The control means is
It was measured for T simultaneously: the measurement of i _a, the temperature measuring means due to the test piece temperature: anode current density due to the electrochemical cell
Previously determined (1) of the test piece was measured based on a relationship type temperature: T from passive holding current density: calculating a i _p,
The anode current density from said i _a passive holding current density by subtracting i _p, the hydrogen permeation current density: seeking i _H,
An intrusion hydrogen amount measuring apparatus configured to calculate an intrusion hydrogen amount from the hydrogen permeation current density: i _H.

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