JP2016038355A - Test method and test device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a test method and test device for testing a metallic material used in the atmosphere.SOLUTION: A test device 10 measures a current when a metallic material to be tested is electrically decomposed at a certain voltage in an aqueous solution. By stopping the electrolysis when reduction in current beyond a defined value has been measured, aqueous solution 101 is produced in which the metal ion concentration of the metallic material is adjusted to a concentration at which hydroxide of the metallic material occurs. When an electrochemical test of the metallic material is performed, the test device 10 bubbles gas containing air or oxygen in the produced aqueous solution.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a test method and a test apparatus.

  Conventionally, metal materials are corroded and their strength and function are reduced / disappeared, so various tests are performed when they are used, and as a corrosion test for metal materials, the materials are installed under conditions simulating the actual environment, There is a method of evaluating the amount of corrosion and physical properties after a predetermined time.

  For example, as a method for evaluating the amount of corrosion and physical properties by installing a material under conditions simulating a real environment, a salt spray test (for example, Non-Patent Document 1) and a combined cycle test (for example, Non-Patent Document 2) As described above, a test simulating the environment of the area where salt comes in is performed, and a test for confirming the corrosion amount, residual strength, function, etc. after a lapse of a specified time is known.

  In addition, as a corrosion test for metal materials, a method is also known in which a metal to be tested is immersed in various aqueous solutions and electrochemical measurement of the target metal is performed. By conducting such electrochemical measurements and clarifying the electrochemical characteristics and corrosion mechanism of metal materials in detail, we are contributing to the confirmation and improvement of the reliability of metal materials and the development of new metal materials. For example, as a method for electrochemical measurement of metal materials, there is a method in which the metal to be tested and a reference electrode are immersed in various aqueous solutions, and the standard electrode potential, polarization curve, corrosion potential / corrosion current density, etc. of the target metal are measured and calculated. Are known.

JIS Z 2371 “Salt spray test method” JIS H 8502 “Plating corrosion resistance test method” "Rust Prevention Technology School Textbook Basic Course", Japan Association of Rust Prevention Technology, p.48-49

  However, the above-mentioned technique for electrochemically measuring the target metal has a problem in that since the measurement is performed in an aqueous solution, the behavior differs from the corrosion in the atmosphere, and the result reflecting the actual environment cannot be obtained. . In other words, since the conventional electrochemical test is performed in an aqueous solution, there are many points different from actual corrosion in the air, and there are cases where it is not suitable for testing metal materials used in the air. For example, when zinc is corroded even in atmospheric corrosion, the corrosion rate is empirically said to be 1/10 to 1/100 compared to iron. However, when electrochemical measurements of iron and zinc are performed and the corrosion current density is calculated, there is no significant difference between zinc and iron.

  The main causes of the difference between the electrochemical measurement results and the atmospheric corrosion behavior are that a thin corrosion film is not immediately formed on the metal surface, and the metal ion concentration in the immediate vicinity of the metal surface is a metal hydroxide. It is conceivable that the concentration is not such that oxygen is not generated and oxygen is not continuously supplied to the metal surface. For example, in the atmosphere, corrosion products such as zinc hydroxide are immediately formed on the surface of zinc, but in aqueous solution, no corrosion product of zinc is produced by electrochemical measurement in solution, or for a considerably long time. Therefore, the difference between the result of electrochemical measurement and the behavior of atmospheric corrosion occurs.

  In order to solve the above-described problems and achieve the object, the test method of the present invention is performed in an aqueous solution in which the metal ion concentration of a metal material to be tested is adjusted to a concentration that generates a hydroxide of the metal material. The method includes a test step of performing an electrochemical test of the metal material while bubbling a gas containing air or oxygen.

  According to the present invention, it is possible to perform an electrochemical test suitable for testing a metal material used in the atmosphere, and it is easy to estimate the lifetime in the atmosphere before using the metal material. There is an effect.

FIG. 1 is a diagram showing a configuration of a test apparatus according to the first embodiment. FIG. 2 is a diagram showing a state in which zinc is electrolyzed and metal ions are eluted in an aqueous solution. FIG. 3 is a diagram showing a state in which a metal hydroxide is deposited on zinc to form a film. FIG. 4 is a diagram illustrating a state in which electrochemical measurement is performed. FIG. 5 is a diagram for explaining a metal test piece coated with a paint containing a high concentration of metal powder. FIG. 6 is a diagram for explaining a current measurement process at the time of electrolysis. FIG. 7 is a block diagram illustrating a configuration of a control unit in the test apparatus according to the first embodiment. FIG. 8 is a block diagram illustrating a configuration of a control unit in the test apparatus according to the second embodiment.

  Embodiments of a test method and a test apparatus according to the present application will be described below in detail with reference to the drawings. It should be noted that the test method and the test apparatus according to the present application are not limited by this embodiment.

[First embodiment]
In the following embodiment, description will be made using zinc as an example of the metal, but other metals can also be applied. In particular, if the metal (such as titanium, aluminum, zirconium, aluminum, chromium, zinc, lead) that forms a coating of corrosion-resistant corrosion products on the metal surface or an alloy containing them is used, even if it is a metal other than zinc It is suitably used in the form.

  Moreover, even a composite material containing these metals in a high concentration is preferably used. For example, zinc rich paint is a paint containing zinc in a high concentration, but is a paint that protects a substrate from corrosion by an electrochemical sacrificial anticorrosive effect. The test method according to the present embodiment is also suitably used for evaluating steel materials coated with zinc rich paint. Further, the aqueous solution used in the test method according to the present embodiment will be described using a 3% NaCl aqueous solution (where “%” refers to “% by weight”), but other aqueous solutions may be used. The test method according to the present embodiment is applicable. For example, the test method according to the present embodiment is suitably used even when seawater or artificial seawater is used.

[Configuration of test equipment]
FIG. 1 is a diagram showing a configuration of a test apparatus 10 according to the first embodiment. The test apparatus 10 illustrated in FIG. 1 includes a measurement unit 20, a control unit 30, a bubbler 40, zinc 50, a reference electrode 60, a counter electrode 70, a stir bar 80, a stirrer 90, and an aqueous solution 101.

  The test apparatus 10 performs electrochemical measurement of a metal material while bubbling a gas containing air or oxygen in an aqueous solution in which the metal ion concentration of the metal material to be tested is adjusted to a concentration that generates a hydroxide of the metal material. It is a device that can perform tests.

  The measurement part 20 measures the electric current at the time of electrolyzing a metal material with a fixed voltage in aqueous solution. Moreover, the measurement part 20 may measure the voltage at the time of electrolyzing the metal material used as test object in aqueous solution with a fixed electric current. The measurement unit 20 is, for example, a potentiostat or a galvanostat, and measures a current while applying a constant voltage, or measures a voltage while flowing a constant current. Further, the measurement unit 20 notifies the control unit 30 of the measured current value or voltage value.

  When the measurement unit 20 determines that the current has decreased below the specified value, the control unit 30 stops the electrolysis, so that the metal ion concentration is adjusted to a concentration that generates a hydroxide of the metal material. Make an aqueous solution. For example, the control unit 30 is a computer such as a personal computer or a workstation. When the current measured by the measurement unit 20 is measured to be reduced to 1/3 or less of the current measured at the beginning of electrolysis, A program to stop disassembly is incorporated.

  Note that the control unit 30 may stop the electrolysis when the measurement unit 20 determines that the voltage has risen above a specified value. For example, the control unit 30 may stop the electrolysis when the voltage measured by the measuring unit 20 is three times the voltage measured in the initial stage of electrolysis, and automatically prepare the aqueous solution 101. Good.

  The bubbler 40 bubbles a gas containing air or oxygen in the aqueous solution 101 when performing an electrochemical test of a metal material. As an example of bubbling conditions, oxygen is supplied at a gas flow rate of 100 mL / min or more with respect to a liquid volume of 500 mL. Moreover, since it is desirable that the oxygen in the solution has reached the saturation solubility value at the time of measurement, it is desirable to perform bubbling at least 20 minutes before the measurement.

  Zinc 50 is a metal material to be tested. The zinc 50 acts as an anode electrode, and the counter electrode 70 acts as a cathode electrode. At this time, a potential difference is generated between the zinc 50 and the counter electrode 70, whereby a coupling current flows between the zinc 50 and the counter electrode 70. The reference electrode 60 is immersed in the aqueous solution 101 and serves as a reference electrode when measuring the potential of the zinc 50.

  The stirrer 80 is installed at the bottom of the container of the aqueous solution 101 and is driven by the stirrer 90. The stirrer 90 drives the stirrer 80 to stir the aqueous solution 101. The aqueous solution 101 is an aqueous solution in which the metal ion concentration of the metal material to be tested is adjusted to a concentration that generates a hydroxide of the metal material.

[Test method flow]
Here, the flow of the test method according to the present embodiment will be described with reference to FIGS. First, the test apparatus 10 electrolyzes a target metal to be tested and elutes metal ions in an aqueous solution. For example, as illustrated in FIG. 2, a case where the target metal is zinc 50 will be described as an example. In the test apparatus 10, when a zinc sample is electrolyzed using a power source in a 3% NaCl aqueous solution, Then, the zinc 50 corrodes and zinc ions are released into the aqueous solution.

  When the electrolysis is continued, the metal ion concentration of the target metal increases, the concentration product of the metal ion and hydroxide ion exceeds the solubility product of the metal hydroxide, and the metal hydroxide precipitates on the target metal. Form a film. Here, when the coating is formed, the electrolysis is stopped to obtain an aqueous solution 101 in which metal ions are saturated at the pH, and a sample with a coating of metal hydroxide (in the example of FIG. 3). A zinc sample 102) is obtained.

  That is, as illustrated in FIG. 3, in the test apparatus 10, since the zinc ion concentration in the aqueous solution increases with time, the concentration product of zinc ions and hydroxide ions exceeds the solubility product of zinc hydroxide, When zinc hydroxide begins to deposit on the surface of zinc 50 serving as the anode, the electrolysis is stopped and the aqueous solution 101 is produced.

  At this time, since the zinc ion concentration in the vicinity of the surface of the zinc 50 is high, zinc hydroxide may begin to precipitate before the entire solution becomes sufficient zinc ions. In order to prevent this, the aqueous solution 101 is produced by carrying out electrolysis while stirring the aqueous solution. Then, as illustrated in FIG. 4, after the aqueous solution is prepared, a metal hydroxide film is formed on the target metal, and the aqueous solution is subjected to electrochemical measurement in a state where the metal ions of the target metal are saturated at the pH. To do. In addition, when it is desired to measure and observe the state of formation of hydroxide on the target metal, it is preferable to perform measurement by exchanging the target metal with a new one while leaving the aqueous solution as it is.

[Preparation of aqueous solution by adding metal salt]
Further, as a method other than the electrolysis described above, the metal ion concentration of the metal material can be reduced by adding a metal salt that generates the same metal ion as the metal ion generated when the metal material corrodes to the aqueous solution. An aqueous solution 101 ′ adjusted to a concentration that produces a product may be prepared. For example, an aqueous solution 101 ′ is prepared by adding an amount of zinc chloride such that the concentration product of zinc ions and hydroxide ions is equal to the solubility product of zinc hydroxide to a 3% NaCl aqueous solution. When zinc hydroxide is used, zinc chloride is used because the pH of the aqueous solution changes and becomes weakly alkaline. If too much zinc chloride is used, the aqueous solution becomes weakly acidic, so it is necessary to add an appropriate amount calculated from the solubility product of zinc hydroxide.

For example, in the case of zinc hydroxide, Ksp = 1.2 × 10 ⁻¹⁷ , so in the case of a 3% NaCl solution at pH 7, [Zn ²⁺ ] [OH ⁻ ] ² = 1.2 × 10 ⁻¹⁷ , [OH Zinc chloride may be added so that the value of ⁻ ] = 10 ⁻⁷ to [Zn ²⁺ ] = 1.2 × 10 ⁻³ mol / L. If the volume of the aqueous solution is 0.1 L, 1.2 × 10 ⁻⁴ mol of ZnCl ₂ may be added, so 136.315 × 1.2 × 10 ⁻ over ZnCl ₂ molar mass of 136.315 g / mol. ⁴ = 0.0164 g of ZnCl ₂ may be added.

[Electrochemical measurement]
Next, electrochemical measurement using the aqueous solution 101 or 101 ′ will be described. When electrochemical measurement is performed after the aqueous solution 101 is produced, the zinc sample 102 is in a state where zinc hydroxide is attached as shown in FIG. If measurement of zinc 50 with zinc hydroxide attached is desired, it may be used for the test as it is. In addition, when it is desired to measure the process in which the protective coating of zinc hydroxide is formed, the measurement should be performed after replacing the zinc sample with a new one (a sample having no corrosion product).

  In addition, when electrochemical measurement is performed after preparing the aqueous solution 101 ′, since zinc hydroxide is not attached to the zinc sample, it is suitable for measuring a process in which a protective coating of zinc hydroxide is formed. If it is desired to measure the zinc 50 with zinc oxide attached, electrolysis is performed using zinc as an anode in the same manner as in the preparation of the aqueous solution 101, so that a zinc sample with zinc hydroxide attached (zinc sample) 102 ′) can be obtained, and zinc in a state where zinc hydroxide is immediately attached can also be measured.

  Next, a case where electrochemical measurement of zinc in a state where zinc hydroxide is attached using the aqueous solutions 101 and 101 'will be described. Here, a combination of the aqueous solution 101 and the zinc sample 102 in which zinc hydroxide adheres to the surface of the zinc sample formed in the process of preparing the aqueous solution 101, or zinc hydroxide on the surface of the zinc sample by electrolysis after the preparation of the aqueous solution 101 ′ and the aqueous solution 101 ′ A combination of deposited zinc samples 102 'is used.

  A zinc hydroxide film is formed on the surfaces of these zinc samples 102 and 102 ′, and the corrosion current density calculated is low when, for example, polarization measurement is performed in order to suppress corrosion. It becomes. When performing polarization measurement, it is desirable to use different samples for the cathode polarization curve measurement and the anodic polarization curve measurement, not the same sample.

  On the other hand, when the polarization measurement is performed in a 3% NaCl aqueous solution without zinc hydroxide adhering to the test method according to this embodiment, the zinc ion concentration in the aqueous solution is low. Therefore, since zinc hydroxide does not precipitate, the measurement is performed in a state where the zinc 50 is easily corroded. For example, when polarization measurement is performed, the calculated corrosion current density is a high value. In actual atmospheric corrosion, wet corrosion, which is water-mediated corrosion, becomes a problem in a general environment. In this case, a thin water film is formed on the metal surface.

  However, since the volume of water is small, zinc corrodes and zinc ions are released into the water, so the zinc ion concentration increases, and immediately bonds with hydroxide ions to form a zinc hydroxide film, which corrodes. It is suppressed. In addition, the thickness of the film immediately formed in the atmospheric test is about several μm, and the subsequent change in film thickness varies depending on the presence or absence of chloride ions and the influence of wind and rain, and the final film thickness is several μm to several A wide range of 100 μm. When there is no chloride ion, a thin and dense film forms a relatively thick and porous film when chloride is present. Also in the case of electrolysis, the final thickness of the sodium chloride solution is about several hundred μm.

  Thus, it can be seen that the test method according to the present embodiment is close to the actual corrosion in the atmosphere. For example, when the actual corrosion rate in the atmosphere is compared between iron and zinc, it is empirically known that the corrosion rate of zinc is about 1/10 to 1/100, which is different by one digit or more. In electrochemical measurements without using a form test method, the corrosion current density is slightly lower than that of iron, and no significant difference is observed as compared to the corrosion rate in the atmosphere.

  Conventionally, in order to perform electrochemical measurement with a coating of a metal corrosion product, zinc is immersed in an aqueous solution (for example, seawater or a 3% NaCl aqueous solution) for a long period (for example, several months). However, when the test method according to the present embodiment is used, a solution (saturated solution of metal ions at that pH) and a corrosion product substantially equal to the solubility product of metal hydroxide in a short time are used. Since a sample with a coating can be prepared, electrochemical measurements can be performed by reproducing samples and solutions in which corrosion is suppressed by the corrosion product coating in a short time (eg, several days when polarized at 100 mV). It can be carried out.

  In addition, a solution (a saturated solution of metal ions at that pH) in which the concentration product of hydroxide ions and metal ions is almost equal to the solubility product of metal hydroxide is obtained. If a sample in which no product is generated is measured, a corrosion product film starts to be formed immediately, so that the formation process of the corrosion product film can be measured in a short time.

  In the test method according to the present embodiment, air (or a gas containing oxygen) is always bubbled into the aqueous solution during electrochemical measurement. This is because in actual atmospheric corrosion, since corrosion proceeds in a thin water film, the oxygen concentration is always at or near the saturation concentration, and thus approaches that. When electrochemical measurement is performed without bubbling air (or a gas containing oxygen), after oxygen in the aqueous solution is consumed, the oxygen supply by diffusion of the oxygen in the liquid becomes the rate-determining, and consistency with atmospheric corrosion is obtained. The possibility of unsuccessful experimental results increases.

  As an example of bubbling conditions, oxygen is supplied at a gas flow rate of 100 mL / min or more with respect to a liquid volume of 500 mL. Since it is desirable that the oxygen in the solution has reached the saturation solubility value at the time of measurement, it is desirable to perform bubbling at least 20 minutes before the measurement. Further, since it is desirable that the solution has a uniform oxygen concentration at the time of measurement, the solution is always stirred with a magnetic stirrer together with bubbling.

[Measurement of metal specimen coated with paint containing metal powder at high concentration]
Next, a case where a metal test piece coated with a paint containing a high concentration of metal powder is measured will be described. For example, by preparing a sample in which zinc rich paint is applied to an SS400 steel plate to which a lead wire is connected, performing electrochemical measurement, measuring polarization, and measuring corrosion current density, the life of zinc rich paint in an actual environment can be improved. It is possible to estimate whether it is longer or shorter than galvanizing.

  At this time, for example, as illustrated in FIG. 5, the lead wire may be connected to SS 400 and then painted with zinc rich paint on SS 400. Zinc rich paint is conductive, but the resistance is quite high, and if the zinc rich paint begins to corrode, the conductivity between the lead wire and the sample will decrease, so the lead wire must be connected to the substrate to be coated. It is desirable to paint.

[Automatic preparation of aqueous solution]
Next, a method and apparatus for automatically producing the aqueous solution 101 will be described. In the test apparatus 10, a potentiostat or a galvanostat is used as the measuring unit 20. When these are used, the current is measured while applying a constant voltage, or the voltage is measured while a constant current is flowing. It is possible to

  For example, when electrolysis is performed using the target metal zinc 50 as an anode, the test apparatus 10 measures the current while applying a constant voltage because a corrosion product film is formed as a resistance. Then, the metal ion concentration increases, and as the corrosion product film is formed, the resistance increases and the current value decreases.

  Therefore, for example, as illustrated in (1) of FIG. 6, the test apparatus 10 stops the electrolysis when the measured current becomes 1/3 of the current measured in the initial stage of electrolysis. The aqueous solution 101 can be automatically produced. Alternatively, the test apparatus 10 may stop the electrolysis when the measured current becomes 1/3 of the current measured in the early stage of electrolysis and the current value hardly changes.

  Further, if the voltage is measured while a constant current is passed, the metal ion concentration increases, and as the corrosion product film is formed, the resistance increases and the voltage increases. Therefore, for example, as illustrated in (2) of FIG. 6, the test apparatus 10 can automatically stop the electrolysis when the measured voltage becomes three times the voltage measured at the beginning of electrolysis. Thus, the aqueous solution 101 can be produced. Alternatively, the electrolysis may be stopped when the voltage hardly changes after the voltage to be measured becomes three times the voltage measured at the beginning of electrolysis.

[Automatic calculation of the amount of metal salt to be added]
Next, a case where the amount of metal salt added by the control unit 30 in order to easily produce the aqueous solution 101 ′ will be described. Here, a configuration example of the control unit 30 will be described with reference to FIG. As illustrated in FIG. 7, the control unit 30 includes a storage unit 31, an input unit 32, a calculation unit 33, and an output unit 34.

  The storage unit 31 is a storage device such as a random access memory (RAM) or a read only memory (ROM), and stores the solubility product of various corrosion products and the molar mass of the metal salt. The input unit 32 is an input device such as a keyboard or a mouse, and accepts input of the volume and pH of the aqueous solution.

  When the volume and pH of the aqueous solution are input to the input unit 32, the calculation unit 33 calculates the amount of metal salt to be added from the metal ion concentration that is equal to the solubility product of the metal oxide at the input pH. The output unit 34 displays the addition amount of the metal salt calculated by the calculation unit 33.

  For example, when zinc is tested in a 3% NaCl solution, it is zinc hydroxide that precipitates as a corrosion product, so zinc chloride may be used as the metal salt. When zinc hydroxide is used, zinc chloride is used because the pH of the aqueous solution changes and becomes weakly alkaline. If too much zinc chloride is used, the aqueous solution becomes weakly acidic, so it is necessary to add an appropriate amount calculated from the solubility product of zinc hydroxide.

For example, in the case of zinc hydroxide, it is Ksp = 1.2 × 10 ⁻¹⁷ molar mass 136.315 g / mol. Next, the volume and pH of the aqueous solution are input to the input unit 32. Here, it is set to 100 mL and pH 7. In the case of pH 7, when the zinc ion concentration equal to the solubility product of zinc hydroxide is calculated, Ksp = [Zn ²⁺ ] [OH ⁻ ] ² = 1.2 × 10 ⁻¹⁷ , [OH ⁻ ] = 10 ⁻⁷ Therefore, zinc chloride which becomes [Zn ²⁺ ] = 1.2 × 10 ⁻³ mol / L may be added. If the volume of the aqueous solution is 100 mL, 1.2 × 10 ⁻³ mol / L × 0.1 L = 1.2 × 10 ⁻⁴ mol of ZnCl ₂ may be added, so that the molar mass of ZnCl ₂ is 136.315 g / It is sufficient to add 136.315 × 1.2 × 10 ⁻⁴ = 0.0164 g of ZnCl ₂ over mol. The calculated addition amount of zinc chloride is displayed on the output unit 34 as a calculation result.

  Also, the solubility product of various metal corrosion products and the molar masses of various metal salts are registered in the storage unit 31, and the volume and pH of the aqueous solution are entered to execute the calculation. The amount of the metal salt added is calculated, and the aqueous solution 101 ′ can be easily prepared.

[Effect of the first embodiment]
As described above, in the test method according to the first embodiment, the metal ion concentration of the metal material to be tested includes air or oxygen in the aqueous solution adjusted to a concentration that generates a hydroxide of the metal material. Electrochemical testing of metal materials while bubbling gas. For this reason, an electrochemical test suitable for the test of the metal material used in the atmosphere can be performed, and it becomes easy to estimate the lifetime in the atmosphere before using the metal material.

  That is, in the test method according to the first embodiment, electrochemical measurement can be performed while maintaining the environment in the vicinity of the test target metal in the solution in a state close to the state in the air atmosphere. It is possible to obtain information on the reaction rate such as the corrosion current value, and it is possible to estimate the deterioration behavior and predict the life in a real environment by measuring in a short time.

[Second Embodiment]
In the first embodiment described above, the case where the metal ion concentration equal to the solubility product of the metal oxide is calculated has been described. However, based on the calculated metal ion concentration, the electric current having such a metal ion concentration is calculated. Decomposition conditions may be calculated and sent to a measurement unit (potential stat or galvanostat).

  FIG. 8 is a block diagram showing a configuration of the control unit 30A in the test apparatus according to the second embodiment. As shown in FIG. 8, the control unit 30 </ b> A is different from the control unit 30 of FIG. 7 in that it further includes a calculation unit 35 and a transmission unit 36.

  The calculation unit 35 calculates the electrolysis conditions for the metal ion concentration based on the metal ion concentration calculated by the calculation unit 33 and equal to the solubility product of the metal hydroxide, and calculates the calculated electrolysis. Is sent to the transmission unit 36. For example, the calculation unit 35 uses the value of the metal ion concentration to calculate electrolysis conditions using a predetermined calculation formula. Further, the calculation unit 35 has a table in which the metal ion concentration value and the electrolysis condition are associated in advance, and the electrolysis condition can be obtained from the metal ion concentration value using the table. Good. Here, the electrolysis condition is, for example, a voltage value, a current value, a voltage that is a fraction of the initial value, or a current that is a fraction of the initial value, or the like. .

  The transmission unit 36 transmits the electrolysis conditions calculated by the calculation unit 35 to the measurement unit (potential stat or galvanostat) 20. When receiving the electrolysis conditions from the transmission unit 36, the measurement unit 20 sets the electrolysis conditions. Accordingly, the test apparatus stops the electrolysis when the set electrolysis conditions are satisfied.

  As described above, in the test method according to the second embodiment, the electrolysis conditions are automatically calculated in order to calculate the electrolysis conditions that achieve such metal ion concentrations based on the calculated metal ion concentrations. It is possible to set the electrochemical test more easily.

  As mentioned above, although this invention was demonstrated using some embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above-described embodiment. In addition, it is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  In addition, among the processes described in this embodiment, all or part of the processes described as being automatically performed can be manually performed, or the processes described as being manually performed All or a part of the above can be automatically performed by a known method. In addition, the processing procedure, control procedure, specific name, and information including various data and parameters shown in the above-described document and drawings can be arbitrarily changed unless otherwise specified.

  Further, the processing of the control units 30 and 30A in the test apparatus described in the present embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. This program can be distributed via a network such as the Internet. The program can also be executed by being recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, and a DVD and being read from the recording medium by the computer.

DESCRIPTION OF SYMBOLS 10 Test apparatus 20 Measuring part 30, 30A Control part 31 Memory | storage part 32 Input part 33 Calculation part 34 Output part 35 Calculation part 36 Transmission part 40 Bubbler 50 Zinc 60 Reference electrode 70 Counter electrode 80 Stirrer 90 Stirrer

Claims (8)

  A test in which an electrochemical test of the metal material is performed while bubbling air or a gas containing oxygen in an aqueous solution in which the metal ion concentration of the metal material to be tested is adjusted to a concentration that generates a hydroxide of the metal material. A test method comprising steps. Electrolyzing the metal material in an aqueous solution, and further comprising a production step of preparing an aqueous solution in which the metal ion concentration is adjusted to a concentration that generates a hydroxide of the metal material;
2. The test method according to claim 1, wherein in the test step, the metal material is subjected to an electrochemical test while bubbling a gas containing air or oxygen in the aqueous solution prepared in the preparation step. A measurement step for measuring a current when electrolyzing the metal material at a constant voltage in an aqueous solution;
When the measurement step determines that the current has fallen below a specified value, the electrolysis is stopped to produce an aqueous solution in which the metal ion concentration is adjusted to a concentration that produces a hydroxide of the metal material. And further comprising a production step,
2. The test method according to claim 1, wherein in the test step, the metal material is subjected to an electrochemical test while bubbling a gas containing air or oxygen in the aqueous solution prepared in the preparation step. A measurement step for measuring a voltage when the metal material is electrolyzed at a constant current in an aqueous solution;
When the measurement step determines that the voltage has risen above a specified value, the electrolysis is stopped to produce an aqueous solution in which the metal ion concentration is adjusted to a concentration that produces a hydroxide of the metal material. And further comprising a production step,
2. The test method according to claim 1, wherein in the test step, the metal material is subjected to an electrochemical test while bubbling a gas containing air or oxygen in the aqueous solution prepared in the preparation step. An aqueous solution in which the metal ion concentration of the metal material is adjusted to a concentration that generates a hydroxide of the metal material by adding a metal salt that generates the same metal ion as that generated when the metal material corrodes to the aqueous solution. And further comprising a production step of producing
2. The test method according to claim 1, wherein in the test step, the metal material is subjected to an electrochemical test while bubbling a gas containing air or oxygen in the aqueous solution prepared in the preparation step. A measurement unit for measuring a current when electrolyzing a metal material to be tested in an aqueous solution at a constant voltage;
An aqueous solution in which the metal ion concentration of the metal material is adjusted to a concentration that generates a hydroxide of the metal material by stopping electrolysis when the measurement unit determines that the current has decreased to a specified value or more. A production part for producing
A bubbler for bubbling air or a gas containing oxygen in the aqueous solution produced by the production part when performing an electrochemical test of the metal material;
A test apparatus comprising: A measuring unit for measuring a voltage when electrolyzing a metal material to be tested in an aqueous solution at a constant current;
An aqueous solution in which the metal ion concentration of the metal material is adjusted to a concentration that generates a hydroxide of the metal material by stopping electrolysis when the voltage is measured by the measurement unit to be higher than a specified value. A production part for producing
A bubbler for bubbling air or a gas containing oxygen in the aqueous solution produced by the production part when performing an electrochemical test of the metal material;
A test apparatus comprising: By adding a metal salt that generates the same metal ion as the metal ion generated when the metal material to be tested corroded to the aqueous solution, the metal ion concentration of the metal material is adjusted to a concentration that generates a hydroxide of the metal material. A production unit for producing the prepared aqueous solution;
A bubbler for bubbling air or a gas containing oxygen in the aqueous solution produced by the production part when performing an electrochemical test of the metal material;
A test apparatus comprising:

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