JP4826872B2 - Corrosion evaluation equipment - Google Patents

Description

The present invention relates to a corrosion evaluation apparatus that can suppress the deterioration of the function of a salt bridge and can perform corrosion evaluation in the same state as the operating temperature of a sample, and more particularly, an electric power used as an evaluation of the corrosion resistance of a fuel cell separator. chemical corrosion evaluation relates to the corrosion evaluation equipment that enables a high temperature is a battery environment.

  2. Description of the Related Art Conventionally, an apparatus for evaluating performance such as corrosivity using a fuel cell separator or the like as a sample (test electrode) has been used.

  For example, Japanese Patent Application Laid-Open No. 2003-272649 discloses a device for measuring a polarization current by an electrochemical polarization characteristic evaluation method, a cell electromotive force during a power generation test, and a separator lifetime for a prototype of a fuel cell separator. (Patent Document 1). In this apparatus, when the separator prototype is evaluated, the prototype and the counter electrode are disposed in the acidic liquid, and the liquid tank and the reference electrode are connected by a salt bridge.

  However, in this device, if the temperature in the liquid tank is set to the same level as the temperature during fuel cell operation for the corrosion evaluation of the separator, there is a temperature difference between the reference electrode and the salt bridge (agar) dissolves. There is a problem that accurate corrosion evaluation cannot be performed.

  As a corrosion resistance evaluation apparatus for metal separators for fuel cells, an electrochemical corrosion evaluation apparatus using a three-electrode system is used. An example of a conventional corrosion evaluation apparatus that uses a three-electrode system is the corrosion evaluation apparatus 30 shown in FIG. FIG. 3 is a schematic configuration diagram of a conventional corrosion evaluation apparatus and shows an arrangement example of a general corrosion evaluation apparatus.

  As shown in FIG. 3, the corrosion evaluation apparatus 30 includes an electrolytic cell 31 containing the test electrode 1 and the counter electrode 2, a reference electrode vessel 13 containing the reference electrode 3, and the electrolytic vessel 31 and the reference electrode vessel. 13 has a structure including a salt bridge 32 made of agar that electrically connects 13, and a main body 15 electrically connected to the test electrode 1, the counter electrode 2, and the reference electrode 3 by wiring. Around the electrolytic cell 31, temperature adjustment water 33 for adjusting the solution in the electrolytic cell 31 to a desired temperature is disposed.

However, when the corrosion evaluation is performed at a high temperature using the corrosion evaluation apparatus 30 shown in FIG. 3, the agar as the salt bridge is dissolved at about 60 ° C. For this reason, when the electrolytic cell 31 containing the test electrode 1 is heated to a high temperature of 60 ° C. or more, which is the fuel cell environment, the agar is melted and the solutions of the electrolytic cell 31 and the reference electrode cell 13 are mixed. Corrosion cannot be evaluated. Moreover, in the silver-silver chloride electrode generally used as the reference electrode 3, the solution in the reference electrode tank 13 is a potassium chloride (KCl) solution, so that chloride ions are mixed into the electrolytic tank 31. This is an important problem in corrosion evaluation tests where it is desirable to avoid mixing chloride ions.
JP 2003-272649 A

The problem to be solved by the present invention is the problem of the prior art described above.
Accordingly, an object of the present invention is to provide a corrosion evaluation apparatus capable of suppressing the functional deterioration of a salt bridge and performing an accurate corrosion evaluation in the same state as the use temperature of a sample.

As a result of diligent research, the present inventors have found that the following temperature environment is desired for the sample (test electrode), salt bridge (agar), and reference electrode in the corrosion evaluation apparatus (first knowledge). Obtained.
Temperature environment of the sample: The temperature should be stable and the temperature to be evaluated.
The temperature environment of the salt bridge: The temperature should be stable and the salt bridge agar should not melt.
(It may be room temperature).
Temperature environment of the reference electrode: The temperature is stable and room temperature is desirable (the characteristics of the reference electrode change with temperature)
Because. In many cases, the operation is guaranteed at room temperature.

As a result of further research based on the first knowledge (preferred temperature environment of each part in the corrosion evaluation apparatus), the present inventors have found that the first liquid tank having the sample and the counter electrode in the solution, and the reference electrode A corrosion evaluation apparatus in which the first liquid tank and the second liquid tank are electrically connected, and a temperature environment of a sample such as a test electrode and a temperature environment of a reference electrode Knowledge that the corrosion evaluation apparatus provided with specific temperature adjusting means that controls separately and controls the reference electrode to a temperature of about room temperature (the same temperature) at this time can achieve the object (second knowledge) Got.

The present invention has been made on the basis of the second finding, and includes a first liquid tank having a fuel cell separator and a counter electrode as a sample in a solution, a second liquid tank having a reference electrode tank, and the first liquid tank. A liquid bridge that electrically connects the liquid tank and the second liquid tank; and a salt bridge made of agar that electrically connects the reference electrode tank and the second liquid tank, the first liquid tank A corrosion evaluation apparatus that takes out a part of the solution and uses the part of the taken-out solution as the solution in the second liquid tank, and the temperature of the solution in the first liquid tank and the temperature of the solution in the second liquid tank The temperature adjusting means adjusts the temperature of the solution in the first liquid tank within the operating temperature range of the fuel cell, and adjusts the temperature of the solution in the second liquid tank. to provide corrosion evaluation device, characterized in that the salt bridge is adjusted to a temperature that does not elute the Than is.

The present invention has such a configuration, and a part of the solution in the first liquid tank is adjusted and brought into contact with the use temperature region of the second liquid tank by the temperature adjusting means, so that the function deterioration of the electrical connection portion with the reference electrode is brought about. And corrosion evaluation can be performed in the same state as the use temperature of the sample (test electrode, etc.).
Moreover, even if the sample is subjected to a corrosion evaluation test in any temperature environment, the second liquid tank is always stable in a temperature environment of about room temperature, and an accurate corrosion evaluation is possible.

Further, the corrosion evaluation device this is because it is possible to contact by adjusting the operating temperature range of the salt bridge with temperature adjustment means a portion of the solution in the first tank, inhibiting the function deterioration of the salt bridge At the same time, the corrosion evaluation can be performed in the same state as the use temperature of the sample (test electrode or the like).
In addition, no matter what temperature environment corrosion evaluation test is performed on the sample, the salt bridge portion and the reference electrode are always stable in a temperature environment of about room temperature, and accurate corrosion evaluation becomes possible.

Corrosion evaluation device This is because those having a structure for cooling the agar is a salt bridge portion, it is possible to prevent elution of the agar even in the corrosion evaluation at high temperature.

The corrosion evaluation device, the temperature of the solution of the first liquid tank from in the range of operating temperature of the fuel cell, the exact corrosion rating of the fuel cell separator as a sample can be performed.

Before Symbol first tank of the solution temperature is 60 ° C. or higher der lever of the exact corrosion evaluation of the fuel cell separator can be performed.

Before SL fuel cell separator, when the metallic material is obtained by the separator substrate may be particularly accurately corrosion evaluation of corrosion resistance and the like of the metal separator for a fuel cell, a fuel cell excellent A metal separator can be selected.

ADVANTAGE OF THE INVENTION According to this invention, while suppressing the functional deterioration of a salt bridge, the corrosion evaluation apparatus which can perform exact corrosion evaluation in the same state as the use temperature of a sample is provided .

  Hereinafter, the present invention will be described more specifically with reference to examples of the present invention. However, the present invention is not limited to the examples.

The corrosion evaluation apparatus according to Example 1 has the structure shown in FIG.
As shown in FIG. 1, the corrosion evaluation apparatus 10 according to the first embodiment includes a first electrolytic cell 11 in which a test electrode 1 and a counter electrode 2 are in a solution, and a reference electrode 3 through a reference electrode cell 13. The second electrolytic cell 12 contained in the solution, the salt bridge 4 made of agar electrically connecting the second electrolytic cell 12 and the reference electrode cell 13, and the first electrolytic cell 11 and the second electrode cell 12 are electrically connected. The liquid bridge 14 is connected to the test electrode 1, the counter electrode 2, and the reference electrode 3. The main body 15 is electrically connected to each other by wiring.

  Around the first electrolytic cell 11, temperature adjusting water 21 for adjusting the solution in the first electrolytic cell 11 to a desired temperature is arranged. Further, around the second electrolytic cell 12, temperature adjusting water 22 for adjusting the salt bridge 4 in the second electrolytic cell 12 to a desired temperature is disposed. A liquid bridge 14 is provided between the first electrolytic cell 11 and the second electrolytic cell 12. As the test electrode 1, a sample of a fuel cell metal separator is used.

  And what extracted a part from the solution of the 1st electrolytic vessel 11 is used for the 2nd electrolytic vessel 12 as a solution. The solution of the second electrolytic cell 12 is adjusted to a temperature different from the temperature of the solution of the first electrolytic cell 11 by the temperature adjustment water 22 and is in contact with the salt bridge 4.

  Here, the agar used as the salt bridge 4 will be described in detail. Agar is a common name for galactan and is used as a gelling agent. A characteristic of agar is that it becomes a sol when heated and a gel when cooled. The agar as the salt bridge 4 is used as a form in which an aqueous solution of potassium chloride, potassium nitrate, potassium sulfate or the like is solidified with agar in order to electrically connect the first electrolytic cell 11 and the second electrolytic cell 12.

  The temperature of the solution in the first electrolytic cell 11 is set to 80 ° C. by the temperature adjustment water 21. The temperature of the solution in the first electrolytic cell 11 is not particularly limited, but is evaluated to be within the operating temperature range of the fuel cell (for example, 60 ° C. or higher, preferably 60 ° C. to 90 ° C.). It is desirable from the viewpoint of improving the performance.

  On the other hand, the temperature of the second electrolytic cell 12 is set to 25 ° C. by the temperature adjustment water 22. The temperature of the solution in the second electrolytic cell 12 is not particularly limited as long as it is different from the temperature of the solution in the first electrolytic cell 11, but is particularly 25 ° C. or less in an environment cooled with a coolant such as cooling water. It is desirable.

  Thus, in the corrosion evaluation apparatus 10 according to the first embodiment, the electrolytic cell has two electrolytic cells, the first electrolytic cell 11 containing the test electrode 1 and the second electrolytic cell 12 containing the salt bridge 4 (agar). The temperature of the first electrolytic cell 11 containing the test electrode 1 is adjusted with the temperature adjusting water 21, and the temperature of the second electrolytic cell 12 containing the salt bridge 4 is adjusted with the temperature adjusting water 22. As a result, the test electrode 1 can be placed in a high temperature environment and the salt bridge 4 (agar) can be placed in a low temperature environment (preferably 25 ° C. or less), and the agar is cooled even in a corrosion evaluation test in a high temperature environment. It does not elute and enables accurate corrosion measurement.

  The corrosion evaluation apparatus according to Example 2 has the structure shown in FIG. In FIG. 2, the same members as those used in FIG. 1 are denoted by the same reference numerals.

  As shown in FIG. 2, the corrosion evaluation apparatus 20 according to the second embodiment is the same as the salt bridge 4 except that the reference electrode tank 13 containing the reference electrode 3 is immersed in the second electrolytic tank 12 together with the agar. The structure is the same as that of the corrosion evaluation apparatus 10 according to Example 1 described above. Therefore, what is not described in detail in the second embodiment is applied as appropriate in the first embodiment.

  That is, in the corrosion evaluation apparatus 20 according to the second embodiment, the first electrolytic cell 11 in which the test electrode 1 and the counter electrode 2 are in solution, and the reference electrode 3 is in solution through the reference electrode vessel 13. The second electrolytic cell 12, the salt bridge 4 made of agar electrically connecting the second electrolytic cell 12 and the reference electrode cell 13, and the liquid bridge 14 electrically connecting the first electrolytic cell 11 and the second electrode cell 12. And a main body 15 electrically connected to each of the test electrode 1, the counter electrode 2 and the reference electrode 3 by wiring.

In the second embodiment, temperature adjusting water 22 for adjusting the salt bridge 4 and the reference electrode tank 13 in the second electrolytic cell 12 to a desired temperature is disposed around the second electrolytic cell 12.
And what extracted a part from the solution of the 1st electrolytic vessel 11 is used for the 2nd electrolytic vessel 12 as a solution. The solution in the second electrolytic cell 12 is adjusted to a temperature different from the temperature of the solution in the first electrolytic cell 11 by the temperature adjusting water 22 and is in contact with the salt bridge 4 and the reference electrode cell 13.

  As described above, in the corrosion evaluation apparatus 20 according to the second embodiment, the electrolytic cell has the first electrolytic cell 11 containing the test electrode 1, the salt bridge 4 (agar), and the second electrolytic cell containing the reference electrode cell 13. 12, the temperature of the first electrolytic cell 11 containing the test electrode 1 is adjusted with the temperature adjustment water 21, and the temperature of the second electrolytic cell 12 containing the salt bridge 4 and the reference electrode cell 13 is adjusted. The temperature is adjusted with water 22. As a result, the test electrode 1 can be placed in a high temperature environment, and the salt bridge 4 (agar) and the reference electrode tank 13 can be placed in a low temperature environment (preferably 25 ° C. or less). Since it is cooled, it does not elute and the temperature of the reference electrode tank 13 becomes constant, so that accurate corrosion evaluation can be performed with high accuracy.

  The corrosion evaluation apparatus 20 according to the second embodiment shown in FIG. 2 has a structure that can also adjust the temperature of the reference electrode tank with respect to the corrosion evaluation apparatus 10 according to the first embodiment shown in FIG. That is, both the agar as the salt bridge 4 and the reference electrode tank 13 containing the reference electrode 3 are immersed in the second electrolytic cell 12. For this reason, the corrosion evaluation apparatus 20 has a structure in which the temperature of the reference electrode is actively maintained.

  The present invention suppresses the functional deterioration of the salt bridge, and at the same condition as the working temperature of the sample, can perform an accurate corrosion evaluation, a fuel cell separator with excellent corrosion resistance, power generation efficiency, etc. It has industrial applicability as a fuel cell having excellent performance and a vehicle having excellent performance.

FIG. 1 is a schematic configuration diagram illustrating a corrosion evaluation apparatus according to the first embodiment. FIG. 2 is a schematic configuration diagram illustrating a corrosion evaluation apparatus according to the second embodiment. FIG. 3 is a schematic configuration diagram showing a conventional corrosion evaluation apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,20,30 ... Corrosion evaluation apparatus, 1 ... Test electrode, 2 ... Counter electrode, 3 ... Reference electrode, 4 ... Salt bridge (agar), 11 ... 1st electrolytic cell , 12 ... 2nd electrolytic cell, 13 ... Reference electrode tank, 14 ... Liquid bridge, 15 ... Body part, 21, 22 ... Temperature adjustment water, 31 ... Electrolytic cell, 32 ... Shiobashi (agar), 33 ... Temperature adjustment water

Claims (3)

The liquid which electrically connects the 1st liquid tank which has the separator for fuel cells as a sample , and a counter electrode in a solution, the 2nd liquid tank which has a reference electrode tank, and the 1st liquid tank and the 2nd liquid tank A bridge, and a salt bridge made of agar electrically connecting the reference electrode tank and the second liquid tank, taking out a part of the solution in the first liquid tank, It is a corrosion evaluation device used as a solution in the second liquid tank ,
Temperature adjusting means for adjusting the temperature of the solution in the first liquid tank and the temperature of the solution in the second liquid tank to different temperatures, respectively ;
The temperature adjusting means adjusts the temperature of the solution in the first liquid tank within the operating temperature range of the fuel cell, and adjusts the temperature of the solution in the second liquid tank to a temperature at which the salt bridge does not elute. Characteristic corrosion evaluation device. The corrosion evaluation apparatus according to claim 1, wherein the temperature of the solution in the first liquid tank is 60 ° C or higher. The fuel cell separator, the metal material and the separator base material, the corrosion evaluation apparatus according to claim 1 or 2, wherein.

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