An electrochemical three-electrode system device and an online testing method

Abstract

The invention discloses an electrochemical three-electrode system device and an online testing method. The device comprises an auxiliary electrode, a reference electrode and a working electrode fixed in a container; the auxiliary electrode is composed of an auxiliary electrode wire, a rectangular electrode sheet and an auxiliary electrode suspension wire connected in sequence, and the auxiliary electrode wire and the auxiliary electrode suspension wire are fixed in the container; the reference electrode is composed of a connected platinum rod and a tip and fixed in the container; the working electrode is composed of a connected wire and a working surface and fixed in the container; the reference electrode and the working electrode are placed in an area enclosed by the rectangular electrode sheet, and the working surface of the working electrode is immersed in a test liquid in the container; since the auxiliary electrode is cut from a platinum sheet as a whole, there is no welding; the working electrode is machined from the same material, and there is no welding and insulation packaging problem; the reference electrode is made of a platinum rod, so the test process is not limited by the temperature and pressure of the test solution, and online testing in solutions with any temperature and pressure can be achieved.

Description

Technical Field

[0001] The invention relates to an electrochemical three-electrode system device and an online testing method, belonging to the technical field of corrosion electrochemical testing. Background Art

[0002] During the use of metal equipment, there is always a certain amount of corrosion in a specific environment. The electrochemical three-electrode system can quickly characterize its corrosion tendency and corrosion behavior. At present, the electrochemical three-electrode mainly uses a flat platinum sheet electrode as an auxiliary, a saturated calomel electrode as a reference electrode, and a metal material is made into a test piece of a certain area. A wire is welded on the back of the working surface and encapsulated with epoxy resin (or other insulating materials). The working surface is polished and degreased as a working electrode. The above method has the following disadvantages when making electrochemical three electrodes:

[0003] 1) The above three-electrode manufacturing process is only suitable for testing at room temperature and pressure, and is not suitable for testing in high temperature and high pressure environments;

[0004] 2) Saturated calomel electrode is used as the reference electrode. Generally, the test solution is neutral and contains chloride ions. Acidic or alkaline test solutions or those without chloride ions generally need to be used with the help of a salt bridge. However, the agar in the salt bridge is easily liquefied at high temperatures, making it unusable.

[0005] 3) When the above working electrode manufacturing method is used in a high temperature and high pressure environment, the metal and the packaging material are prone to crevice corrosion at their interface due to different thermal expansion and contraction coefficients, which affects the test results. Summary of the invention

[0006] In view of the problems existing in the prior art, the object of the present invention is to provide an electrochemical three-electrode system device, which is simple and not limited by the temperature and pressure of the test solution. Another object of the present invention is to provide an electrochemical three-electrode system online testing method, which is easy to operate and can realize online testing in solutions of any temperature and pressure.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] An electrochemical three-electrode system device comprises an auxiliary electrode 1, a reference electrode 7 and a working electrode 10 fixed in a container; the auxiliary electrode 1 is composed of an auxiliary electrode wire 2, a rectangular electrode sheet 3 and an auxiliary electrode suspension wire 4 connected in sequence, the auxiliary electrode wire 2 is fixed in the container by an insulating sealing sleeve 6 on the top of the container, and the auxiliary electrode suspension wire 4 is fixed in the container by an insulating fixing plug 5 on the top of the container; the reference electrode 7 is composed of a connected platinum rod 8 and a tip 9, and is fixed in the container by the insulating sealing sleeve 6 on the top of the container; the working electrode 10 is composed of a connected wire 11 and a working surface 12, and is fixed in the container by the insulating sealing sleeve 6 on the top of the container; the reference electrode 7 and the working electrode 10 are placed in the area enclosed by the rectangular electrode sheet 3 of the auxiliary electrode 1, and the working surface 12 of the working electrode 10 is immersed in the test liquid in the container.

[0009] The auxiliary electrode wire 2, the rectangular electrode sheet 3 and the auxiliary electrode suspension wire 4 are cut from the same platinum sheet.

[0010] The rectangular electrode sheet 3 of the auxiliary electrode 1 is folded into a U-shape or a cylindrical shape and is placed parallel to the working surface 12 of the working electrode 10 .

[0011] The reference electrode 7 and the working electrode 10 are placed at the center of the U-shaped or cylindrical auxiliary electrode.

[0012] The tip 9 of the reference electrode 7 is as close as possible to the working surface 12 of the working electrode 10, but does not touch it.

[0013] The lead 11 and the working surface 12 of the working electrode 10 are integrally made of the same metal material by mechanical processing, and no welding or packaging is required.

[0014] The working surface 12 of the working electrode 10 is in a pancake or cylindrical shape with an arc-shaped edge, so as to avoid tip polarization of the working electrode during the test process.

[0015] In the online testing method of the electrochemical three-electrode system device, the auxiliary electrode 1, the reference electrode 7 and the working electrode 10 are respectively connected to the three electrodes of the electrochemical analyzer outside the container to perform analysis and testing; when analyzing the test results, it is necessary to calculate the working area of ​​the working electrode 10, which is the surface area of ​​the working surface 12 completely immersed in the test liquid in the container, and the influence of the wire 11 of the working electrode 10 on the working area of ​​the working electrode is ignored.

[0016] The depth of the test liquid in the container is just enough to cover the working surface 12 of the working electrode 10 .

[0017] In the present invention, the auxiliary electrode is made of a whole cut platinum sheet, and there is no welding; the working electrode is machined from the same material, and there is no welding and insulation packaging problem; the reference electrode is made of a platinum rod, so the test process is not limited by the temperature and pressure of the test solution, and online testing can be achieved in solutions with any temperature and pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of an electrochemical three-electrode system device of the present invention (the working surface of the working electrode is in a circular pancake shape).

[0019] Figure 2 This is a schematic diagram of an electrochemical three-electrode system device of the present invention (the working surface of the working electrode is cylindrical).

[0020] In the figure: 1 auxiliary electrode; 2 auxiliary electrode wire; 3 rectangular electrode sheet; 4 auxiliary electrode suspension wire; 5 insulating fixing plug; 6 insulating sealing sleeve; 7 reference electrode; 8 platinum rod; 9 tip; 10 working electrode; 11 wire; 12 working surface. DETAILED DESCRIPTION

[0021] like Figure 1 and Figure 2 As shown, an electrochemical three-electrode system device includes an auxiliary electrode 1, a reference electrode 7 and a working electrode 10 fixed in a container; the auxiliary electrode 1 is composed of an auxiliary electrode wire 2, a rectangular electrode sheet 3 and an auxiliary electrode suspension wire 4 connected in sequence, the auxiliary electrode wire 2 is fixed in the container by an insulating sealing sleeve 6 on the top of the container, and the auxiliary electrode suspension wire 4 is fixed in the container by an insulating fixing plug 5 on the top of the container; the reference electrode 7 is composed of a connected platinum rod 8 and a tip 9, and is fixed in the container by the insulating sealing sleeve 6 on the top of the container; the working electrode 10 is composed of a connected wire 11 and a working surface 12, and is fixed in the container by the insulating sealing sleeve 6 on the top of the container; the reference electrode 7 and the working electrode 10 are placed in the area enclosed by the rectangular electrode sheet 3 of the auxiliary electrode 1, and the working surface 12 of the working electrode 10 is immersed in the test liquid in the container.

[0022] The characteristics and further improvements of the present invention are:

[0023] Furthermore, the auxiliary electrode wire 2, the rectangular electrode sheet 3 and the auxiliary electrode suspension wire 4 are cut from the same platinum sheet.

[0024] Furthermore, the rectangular electrode sheet 3 of the auxiliary electrode 1 is folded into a U-shape or a cylindrical shape and is placed parallel to the working surface 12 of the working electrode 10 .

[0025] Furthermore, the tip 9 of the reference electrode 7 should be as close as possible to the working surface 12 of the working electrode 10, but not in contact with it.

[0026] Furthermore, the wire 11 and the working surface 12 of the working electrode 10 are integrally made of the same metal material by machining, without the need for welding or packaging.

[0027] Furthermore, the working surface 12 of the working electrode 10 is in the shape of a round cake ( Figure 1 ) or cylindrical ( Figure 2 ), the edge is arc-shaped to avoid tip polarization of the working electrode during the test.

[0028] Furthermore, the reference electrode 7 and the working electrode are placed at the center of the U-shaped or cylindrical auxiliary electrode.

[0029] An electrochemical three-electrode system online testing method adopts the above-mentioned electrochemical three-electrode system manufacturing process, the container immerses the auxiliary electrode 1, the reference electrode 7 and the working electrode 10 in the test liquid, and the auxiliary electrode 1, the reference electrode 7 and the working electrode 10 are respectively connected to the three electrodes of the electrochemical analyzer outside the container, and the analysis test can be carried out; when analyzing the test results, it is necessary to calculate the working area of ​​the working electrode 10, that is, the surface area of ​​the working surface 12 completely immersed in the test liquid (because the surface area of ​​the working surface of the working electrode is much larger than the surface area of ​​the working electrode wire in the test liquid caused by the fluctuation of the liquid level during the test process).

[0030] As a preferred embodiment of the present invention, the depth of the test liquid in the container is just enough to cover the working surface of the working electrode.

Claims

1. An electrochemical three-electrode system device, characterized in that: The invention comprises an auxiliary electrode (1), a reference electrode (7) and a working electrode (10) fixed in a container; the auxiliary electrode (1) is composed of an auxiliary electrode wire (2), a rectangular electrode sheet (3) and an auxiliary electrode suspension wire (4) connected in sequence; the auxiliary electrode wire (2) is fixed in the container by an insulating sealing sleeve (6) at the top of the container; the auxiliary electrode suspension wire (4) is fixed in the container by an insulating fixing plug (5) at the top of the container; the reference electrode (7) is composed of a connected platinum rod (8) and a tip (9), and is fixed in the container by an insulating sealing sleeve (6) at the top of the container; the working electrode (10) is composed of a connected wire (11) and a working surface (12), and is fixed in the container by an insulating sealing sleeve (6) at the top of the container; the reference electrode (7) and the working electrode (10) are placed in the area enclosed by the rectangular electrode sheet (3) of the auxiliary electrode (1), and the working surface (12) of the working electrode (10) is immersed in the test liquid in the container; The auxiliary electrode wire (2), the rectangular electrode sheet (3) and the auxiliary electrode suspension wire (4) are cut from the same platinum sheet; The lead wire (11) and the working surface (12) of the working electrode (10) are integrally made of the same metal material by mechanical processing, and do not require welding or packaging.

2. An electrochemical three-electrode system device according to claim 1, characterized in that: The rectangular electrode sheet (3) of the auxiliary electrode (1) is folded into a U-shape or a cylindrical shape and is placed parallel to the working surface (12) of the working electrode (10).

3. An electrochemical three-electrode system device according to claim 2, characterized in that: The reference electrode (7) and the working electrode (10) are placed at the center of the U-shaped or cylindrical auxiliary electrode.

4. An electrochemical three-electrode system device according to claim 1, characterized in that: The tip (9) of the reference electrode (7) is as close as possible to the working surface (12) of the working electrode (10), but does not touch it.

5. The electrochemical three-electrode system device according to claim 1, characterized in that: The working surface (12) of the working electrode (10) is in the shape of a disk or a cylinder, and its edge is in an arc shape, so as to avoid the tip polarization phenomenon of the working electrode during the test process.

6. The online testing method of the electrochemical three-electrode system device according to any one of claims 1 to 5, characterized in that: The auxiliary electrode (1), the reference electrode (7) and the working electrode (10) are respectively connected to the three electrodes of the electrochemical analyzer outside the container to perform analytical testing; when analyzing the test results, it is necessary to calculate the working area of ​​the working electrode (10), which is the surface area of ​​the working surface (12) completely immersed in the test liquid in the container, and the influence of the wire (11) of the working electrode (10) on the working area of ​​the working electrode is ignored.

7. The online testing method according to claim 6, characterized in that: The depth of the test liquid in the container is just enough to cover the working surface (12) of the working electrode (10).

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