Atmosphere-controllable halide molten salt corrosion long-time electrochemical test method and device

Abstract

The invention relates to the field of electrochemical measurement, and discloses an atmosphere-controllable halide molten salt corrosion long-time electrochemical test method and device, and the device comprises an atmosphere control assembly which is used for providing and maintaining an atmosphere environment; the airtight assembly comprises a pipe sealing joint and is used for enabling the atmosphere control assembly to form a sealed environment; the heating assembly is used for heating the atmosphere control assembly; the measuring assembly is used for monitoring and recording electrochemical signals in the molten salt environment; the heat insulation assembly is used for preventing heat from being dissipated; the impurity treatment assembly is used for removing impurities and by-products released in the testing process. By arranging the airtight assembly, the atmosphere control assembly and the middle pipe sealing joint, a three-stage heat insulation structure can be formed, so that the vapor pressure in the crucible is close to the saturated vapor pressure of molten salt, and the evaporation loss of the molten salt is remarkably reduced; the sealing performance of the flange cover is improved, and the long-term stability of the device in a high-temperature environment and the accuracy of a test result are ensured.

Description

Technical Field

[0001] The invention relates to the field of electrochemical measurement, and in particular to an atmosphere-controllable long-time electrochemical testing method and device for halide molten salt corrosion. Background Art

[0002] Solar thermal power generation technology is considered to be one of the most promising new energy technologies. The third-generation solar thermal power generation technology uses lower-cost halide molten salts (such as chloride molten salts) with higher service temperatures (>700°C). However, chloride molten salts are highly corrosive, which seriously threatens the long-life and high-reliability operation of molten salt equipment. Therefore, in order to achieve high reliability and long-life design of molten salt storage tanks, it is necessary to understand the corrosion behavior and mechanism of candidate structural materials in halide molten salts.

[0003] Electrochemical testing is an efficient and low-cost corrosion testing method. However, most of the existing electrochemical testing devices and methods in high-temperature liquid corrosion environments are mainly suitable for molten salt systems that do not require atmosphere control, such as molten nitrate. These devices and methods have the following shortcomings:

[0004] Temperature limitation: Existing technologies are difficult to operate stably in high-temperature environments above 700°C and cannot meet the requirements of high-temperature molten salt corrosion testing;

[0005] Lack of atmosphere control: The existing technology lacks effective control over specific atmospheres (such as inert gas or vacuum environment), and cannot meet the needs of halide molten salt corrosion testing with extremely high requirements on the atmosphere environment;

[0006] Insufficient long-term testing capabilities: It is difficult to reduce the evaporation loss of molten salt at high temperatures, resulting in the inability of existing devices to achieve long-term electrochemical testing of more than 1,000 hours. The stability of the test and the reliability of the data are also affected. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides an atmosphere-controllable long-term electrochemical testing method and device for halide molten salt corrosion, which solves the problems of temperature limitation, lack of atmosphere control and insufficient long-term testing capability in the existing electrochemical testing.

[0008] To achieve the above objectives, the present invention is implemented by the following technical scheme: an atmosphere-controllable halide molten salt corrosion long-term electrochemical testing device, comprising:

[0009] Atmosphere control components, used to provide and maintain the atmosphere;

[0010] An airtight assembly, which includes a pipe sealing joint, for forming a sealed environment for the atmosphere control assembly;

[0011] Heating assembly, used for heating the atmosphere control assembly;

[0012] A measuring component, which penetrates the airtight component and is located in the atmosphere control component, and is used to monitor and record electrochemical signals in the molten salt environment;

[0013] A heat insulation component, which is located in the atmosphere control component and is used to prevent heat from dissipating;

[0014] The impurity treatment component is connected to the atmosphere control component and is used to remove impurities and by-products released during the test process.

[0015] Preferably, the atmosphere control component includes an airtight container and a high-pressure gas cylinder, a crucible is arranged inside the airtight container, molten salt is arranged inside the crucible, a crucible cover is arranged at the opening of the crucible, a flange cover is installed at the opening of the airtight container, the pipe sealing joint is installed on the top surface of the flange cover, the high-pressure gas cylinder is connected to the air inlet pipe, and an air inlet valve is installed in the middle of the air inlet pipe.

[0016] Preferably, the insulation assembly includes a first insulation brick and a second insulation brick, the second insulation brick is located at the top of the airtight container, the first insulation brick is located in the middle of the airtight container, and the first insulation brick and the second insulation brick are connected by bolts and nuts.

[0017] Preferably, the measuring assembly comprises a working electrode, a reference electrode, a counter electrode and an armored thermocouple, and all three are connected to an electrochemical workstation, and the counter electrode, the reference electrode and the working electrode are all located inside the molten salt;

[0018] The impurity processing component includes an air outlet main pipe, a vacuum pump, a second air outlet branch pipe and a solution tank. The two ends of the air outlet main pipe are respectively connected to the airtight container and the first air outlet branch pipe, the first air outlet branch pipe is connected to the vacuum pump, and a vacuum valve is installed in the middle of the first air outlet branch pipe. The middle of the air outlet main pipe is connected to the second air outlet branch pipe, one side of the second air outlet branch pipe is located inside the processing liquid in the solution tank, and an air outlet valve is installed in the middle of the second air outlet branch pipe.

[0019] Preferably, the pipe sealing joint comprises a hollow stud, a hollow nut and a hollow conical washer, the hollow stud is fixedly connected to the top surface of the flange cover, the hollow nut is threadedly connected to the top of the outer wall of the hollow stud, the hollow conical washer is between the hollow nut and the hollow stud, and a through hole is opened in the middle of the flange cover, and the hollow stud is coaxial with the through hole;

[0020] The gas outlet main pipe passes through the hollow stud, the through hole and the second insulation brick in sequence, and the end portion thereof is located between the second insulation brick and the first insulation brick;

[0021] The working electrode, the reference electrode, the counter electrode and the armored thermocouple are all sequentially passed through the hollow stud, the through hole and the second insulation brick, the first insulation brick and the crucible cover and then placed in the molten salt;

[0022] The air inlet pipe passes through the hollow stud, the through hole, the second insulation brick and the first insulation brick in sequence and is located between the outer wall of the crucible and the inner wall of the airtight container.

[0023] Preferably, the heating assembly includes a high-temperature furnace, and the airtight container is located inside the high-temperature furnace.

[0024] An atmosphere-controlled long-term electrochemical test method for halide molten salt corrosion comprises the following steps:

[0025] Step 1: Packaging electrodes and molten salt:

[0026] All operations in this step were performed in a glove box filled with argon or vacuum;

[0027] Put the prepared molten salt into the crucible, and then connect the crucible cover to the crucible through threads; insert three electrodes and the armored thermocouple into the through holes on the crucible cover respectively until the three electrodes and the armored thermocouple are in the middle of the crucible;

[0028] Step 2: Assembly and atmosphere control:

[0029] Place the packaged crucible in an airtight container, pass the first insulation brick, the second insulation brick, the flange cover, the hollow conical gasket and the hollow nut through the three electrodes and the armored thermocouple in sequence, then install the first insulation brick, the second insulation brick and the flange cover in sequence, then pass the air inlet pipe and the air outlet pipe through the pipe sealing joint in sequence into the airtight container, and finally rotate the hollow nut to compress the hollow conical gasket;

[0030] Step 3, then close the air inlet valve and the air outlet valve, open the vacuum valve, and start the vacuum pump to extract the vacuum; after completion, close the vacuum pump and the vacuum valve, and open the air inlet valve to allow the argon gas to fill the airtight container;

[0031] Step 4: Temperature rise and stability test:

[0032] Close the air inlet valve and vacuum valve, open the air outlet valve, and drive the high-temperature furnace to start heating up;

[0033] When the temperature reaches 700-750°C, the three electrodes are connected to the electrochemical workstation in a circuit, and the open circuit potential change of the system is measured by the open circuit potential method;

[0034] Step 5: Start the test:

[0035] Start the test when the open circuit potential in step 4 reaches stability.

[0036] Preferably, in step 1, the counter electrode, reference electrode, working electrode and armored thermocouple are all in a vertical state with the crucible cover, and high-temperature glue is used to seal the through holes and the gaps between the three electrodes and the armored thermocouple, and the high-temperature glue is cured for standby use.

[0037] Preferably, in step 2, the vacuum degree in the airtight container is less than 1×10 3 When the pressure is below Pascal, close the vacuum pump and vacuum valve.

[0038] Preferably, in step 3, step 3 is repeated 3 to 4 times to fill the airtight container with argon gas.

[0039] The present invention provides a method and device for long-term electrochemical testing of halide molten salt corrosion with controlled atmosphere, which has the following beneficial effects:

[0040] 1. The present invention can form a three-level insulation structure by arranging an airtight component, an atmosphere control component and a middle tube sealing joint, which not only makes the vapor pressure in the crucible close to the saturated vapor pressure of the molten salt, thereby significantly reducing the evaporation loss of the molten salt; at the same time, the insulation component reduces the temperature at the upper end of the airtight container, further improves the sealing performance at the flange cover, and ensures the long-term stability of the device in a high temperature environment and the accuracy of the test results.

[0041] 2. The present invention can complete the vacuum extraction and inert gas replacement operations inside the airtight container and realize strict atmosphere control of the corrosion system by arranging an air inlet valve, an air outlet valve, a vacuum valve and a vacuum pump; at the same time, the impurity gas generated during the reaction can be discharged into the treatment liquid in the solution tank through the air outlet valve, and the impurity gas is neutralized by the treatment liquid, thereby avoiding the pollution of the test atmosphere and environment by corrosion by-products, thereby ensuring the stability and safety of the test environment.

[0042] 3. The present invention uses a hollow stud, a hollow nut and a hollow conical washer. The hollow conical washer can be compressed by rotating the hollow nut, thereby performing multi-point extrusion sealing on the working electrode, the reference electrode, the counter electrode, the armored thermocouple, the gas outlet pipe and the gas inlet pipe, thereby further improving the sealing effect, effectively preventing the leakage of high-temperature molten salt steam and the test gas, and ensuring the airtightness and long-term stability of the device in a long-term high-temperature corrosive environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a structural schematic diagram of the present invention;

[0044] Figure 2 A schematic diagram of a connection method of a first insulation brick and a second insulation brick of the present invention;

[0045] Figure 3 It is a schematic diagram of the pipe sealing joint of the present invention;

[0046] Figure 4 This is the impedance spectrum of the present invention.

[0047] Among them, 1. electrochemical workstation; 2. outlet main pipe; 3. first outlet branch pipe; 4. vacuum valve; 5. vacuum pump; 6. outlet valve; 7. second outlet branch pipe; 8. solution tank; 9. high temperature furnace; 10. crucible; 11. armored thermocouple; 12. counter electrode; 13. molten salt; 14. reference electrode; 15. working electrode; 16. high pressure gas cylinder; 17. airtight container; 18. crucible cover; 19. first insulation brick; 20. second insulation brick; 21. flange cover; 22. inlet valve; 23. inlet pipe; 24. pipe sealing joint; 25. hollow stud; 26. hollow nut; 27. hollow conical washer. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In order to better understand the present invention, the above contents are described in detail below in conjunction with specific embodiments.

[0050] Embodiment 1:

[0051] Please see attached Figure 1 -Attached Figure 3 An embodiment of the present invention provides an atmosphere-controllable halide molten salt corrosion long-term electrochemical testing device, including: an atmosphere control component, used to provide and maintain an atmosphere environment; an airtight component, which includes a pipe sealing joint 24, used to make the atmosphere control component form a sealed environment; a heating component, used to heat the atmosphere control component; a measuring component, which passes through the airtight component and is located in the atmosphere control component, and is used to monitor and record electrochemical signals in the molten salt 13 environment; a thermal insulation component, which is located in the atmosphere control component, and is used to block the dissipation of heat; an impurity treatment component, which is connected to the atmosphere control component, and is used to remove impurities and by-products released during the test.

[0052] The atmosphere control assembly includes an airtight container 17 and a high-pressure gas cylinder 16. A crucible 10 is arranged inside the airtight container 17. Molten salt 13 is arranged inside the crucible 10. A crucible cover 18 is arranged at the opening of the crucible 10. A flange cover 21 is installed at the opening of the airtight container 17. A pipe sealing joint 24 is installed on the top surface of the flange cover 21. The high-pressure gas cylinder 16 is connected to the air inlet pipe 23. An air inlet valve 22 is installed in the middle of the air inlet pipe 23. The heat insulation assembly includes a first heat insulation brick 19 and a second heat insulation brick 20. The second heat insulation brick 20 is located at the top of the airtight container 17. The first heat insulation brick 19 is located in the middle of the airtight container 17. The first heat insulation brick 19 and the second heat insulation brick 20 are connected by bolts and nuts.

[0053] In this embodiment, the molten salt 13 can be placed in the crucible 10 and a reaction space can be provided for it, and the crucible cover 18 can seal the crucible 10. After the crucible 10 is placed inside the airtight container 17, the crucible 10 can be sealed. At the same time, the first insulating brick 19 and the second insulating brick 20 can be used to isolate the heat to avoid heat loss, and the flange cover 21, the crucible cover 18 and the pipe sealing joint can be used to perform three-level insulation on the airtight container 17, which not only makes the vapor pressure in the crucible 10 close to the saturated vapor pressure of the molten salt 13, reducing the evaporation of the molten salt 13, but also significantly reduces the temperature of the upper end of the airtight container 17 through multi-level insulation, thereby making the sealing effect at the flange cover 21 better.

[0054] The measuring assembly includes a working electrode 15, a reference electrode 14, a counter electrode 12 and an armored thermocouple 11, and all three are connected to the electrochemical workstation 1, and the counter electrode 12, the reference electrode 14 and the working electrode 15 are all located inside the molten salt 13;

[0055] In this embodiment, the open circuit potential in the reaction can be detected by the working electrode 15, the reference electrode 14, and the counter electrode 12, and the temperature of the reaction can be detected by the armored thermocouple 11.

[0056] The impurity treatment component includes an air outlet main pipe 2, a vacuum pump 5, a second air outlet branch pipe 7 and a solution tank 8. The two ends of the air outlet main pipe 2 are respectively connected to the airtight container 17 and the first air outlet branch pipe 3. The first air outlet branch pipe 3 is connected to the vacuum pump 5, and a vacuum valve 4 is installed in the middle of the first air outlet branch pipe 3. The middle of the air outlet main pipe 2 is connected to the second air outlet branch pipe 7. One side of the second air outlet branch pipe 7 is located inside the processing liquid in the solution tank 8, and an air outlet valve 6 is installed in the middle of the second air outlet branch pipe 7.

[0057] By closing the air inlet valve 22 and the air outlet valve 6, the gas inside the airtight container 17 can be extracted by opening the vacuum valve 4 and the vacuum pump 5. After closing the vacuum valve 4 and the vacuum pump 5, only the air inlet valve 22 is opened. At this time, argon gas can be filled into the airtight container 17 to provide a reaction environment. In the test, by closing the air inlet valve 22 and the vacuum valve 4 and opening the air outlet valve 6, the gas generated by the reaction can enter the treatment liquid in the solution tank 8, and the gas generated by the reaction can be treated with the treatment liquid.

[0058] The pipe sealing joint 24 includes a hollow stud 25, a hollow nut 26 and a hollow conical washer 27. The hollow stud 25 is fixedly connected to the top surface of the flange cover 21. The hollow nut 26 is threadedly connected to the top of the outer wall of the hollow stud 25. The hollow conical washer 27 is located between the hollow nut 26 and the hollow stud 25. A through hole is opened in the middle of the flange cover 21, and the hollow stud 25 is coaxial with the through hole. The gas outlet main pipe 2 passes through the hollow stud 25, the through hole and the second insulation brick 20 in sequence, and its end is located between the second insulation brick 20 and the first insulation brick 19. The working electrode 15, the reference electrode 14, the counter electrode 12 and the armored thermocouple 11 are all located in the molten salt 13 after passing through the hollow stud 25, the through hole and the second insulation brick 20, the first insulation brick 19 and the crucible cover 18 in sequence.

[0059] The air inlet pipe 23 passes through the hollow stud 25, the through hole, the second insulation brick 20 and the first insulation brick 19 in sequence and is located between the outer wall of the crucible 10 and the inner wall of the airtight container 17. The heating assembly includes a high temperature furnace 9, and the airtight container 17 is located inside the high temperature furnace 9.

[0060] In this embodiment, the hollow nut 26 is rotated, and the hollow conical washer 27 can be pressed between the hollow stud 25 and the hollow nut 26. At this time, the hollow conical washer 27 can be squeezed and deformed, and then the hollow conical washer 27 can squeeze the working electrode 15, the reference electrode 14, the counter electrode 12, the armored thermocouple 11, the air outlet pipe 2 and the air inlet pipe 23, thereby achieving a sealing effect.

[0061] Embodiment 2:

[0062] The method for testing using the above device comprises the following steps:

[0063] Step 1: Packaging electrodes and molten salt 13:

[0064] All operations in this step were performed in a glove box filled with argon or vacuum;

[0065] The prepared molten salt 13 is loaded into the crucible 10, and then the crucible cover 18 is connected to the crucible 10 by threads; three electrodes and the armored thermocouple 11 are respectively inserted into the through holes on the crucible cover 18 until the three electrodes and the armored thermocouple 11 are in the middle position of the crucible 10;

[0066] Step 2: Assembly and atmosphere control:

[0067] Place the packaged crucible 10 in the airtight container 17, pass the first insulation brick 19, the second insulation brick 20, the flange cover 21, the hollow conical gasket 27 and the hollow nut 26 through the three electrodes and the armored thermocouple 11 in sequence, then install the first insulation brick 19, the second insulation brick 20 and the flange cover 21 in sequence, then pass the air inlet pipe 23 and the air outlet main pipe 2 through the pipe sealing joint 24 in sequence into the airtight container 17, and finally rotate the hollow nut 26 to press the hollow conical gasket 27;

[0068] Step 3, then close the air inlet valve 22 and the air outlet valve 6, open the vacuum valve 4, and start the vacuum pump 5 to extract the vacuum; after completion, close the vacuum pump 5 and the vacuum valve 4, and open the air inlet valve 22 to allow the argon gas to fill the airtight container 17;

[0069] Step 4: Temperature rise and stability test:

[0070] Close the air inlet valve 22 and the vacuum valve 4, open the air outlet valve 6, and drive the high temperature furnace 9 to start heating;

[0071] When the temperature reaches 700-750°C, the three electrodes are connected to the electrochemical workstation 1 in a circuit, and the open circuit potential change of the system is measured by the open circuit potential method;

[0072] Step 5: Start the test:

[0073] Start the test when the open circuit potential in step 4 reaches stability.

[0074] In step 1, the counter electrode 12, reference electrode 14, working electrode 15, armored thermocouple 11 and crucible cover 18 are all in a vertical state, and high-temperature glue is used to seal the through holes and the gaps between the three electrodes and armored thermocouple 11, and the high-temperature glue is cured for use.

[0075] In step 2, when the vacuum is drawn, the vacuum degree in the airtight container 17 is less than 1×10 3 When the pressure is below Pascal, close the vacuum pump 5 and the vacuum valve 4.

[0076] Preferably, in step 3, step 3 is repeated 3 to 4 times to fill the airtight container 17 with argon gas.

[0077] Embodiment three:

[0078] Please see attached Figure 4 , based on Example 1 and Example 2

[0079] Conduct electrochemical impedance spectroscopy tests in a high temperature chloride molten salt environment

[0080] Wherein: the composition of the molten salt 13 is: 45.4MgCl%-33%KCl-21.6%NaCl, the test temperature is 700°C, the test materials are IN800H alloy (No. 1) and IN625 alloy (No. 2), and the sine wave amplitude is 5mV.

[0081] Step 1: Packaging electrodes and molten salt 13:

[0082] All operations in this step were performed in a glove box filled with argon or vacuum.

[0083] Put the prepared chloride molten salt 13 into the crucible 10, and then connect the crucible cover 18 to the crucible 10 through threads; insert the three electrodes and the armored thermocouple 11 into the through holes on the crucible cover 18 respectively, until the three electrodes and the armored thermocouple 11 are in the middle of the crucible 10; make the three electrodes and the armored thermocouple 11 in a vertical state, and then use high-temperature glue to seal the gaps between the through holes and the three electrodes and the armored thermocouple 11, and wait for the high-temperature glue to solidify before use;

[0084] Step 2: Assembly and atmosphere control:

[0085] The packaged crucible 10, molten salt 13, three electrodes and armored thermocouple 11 are placed in an airtight container 17, and the first insulation board, the second insulation board and the flange cover 21 are passed through the three electrodes and the armored thermocouple 11 in sequence. The through holes of the three electrodes and the armored thermocouple 11 and the flange cover 21 are sealed with a pipe sealing joint 24; the flange cover 21 is connected and sealed to the airtight container 17.

[0086] Step 3: close the air inlet valve 22 and the air outlet valve 6, open the vacuum valve 4, and start the vacuum pump 5 to extract the vacuum; wait until the vacuum degree in the airtight container 17 reaches 1×10 3 When the pressure is below Pascal, the vacuum pump 5 and the vacuum valve 4 are turned off, and the air inlet valve 22 is opened to allow the argon gas to fill the airtight container 17. This operation is repeated three times.

[0087] Step 4: Temperature rise and stability test:

[0088] Close the air inlet valve 22 and the vacuum valve 4, open the air outlet valve 6, and drive the high temperature furnace 9 to start heating;

[0089] After the temperature reaches 700°C, the three electrodes are connected to the electrochemical workstation 1 in a circuit, and the open circuit potential change of the system is measured by the open circuit potential method;

[0090] Step 4: Start the test:

[0091] When the open circuit potential in step 3 reaches stability, select electrochemical impedance spectroscopy, set the sine wave amplitude to 5mV, the frequency range to 10mHz to 100kHz, and start collecting impedance spectra after 1000 hours of immersion.

[0092] The long-term electrochemical test of chloride molten salt 13 corrosion under this atmosphere lasted for 1100 hours, the sample was completely immersed in molten salt 13, and the atmosphere was always an argon environment. Then the electrochemical impedance spectrum of chloride molten salt 13 corrosion under this atmosphere was recorded for 1000 hours.

[0093] As can be seen from the figure, the measured impedance data fluctuates little and can accurately reveal the difference in corrosion resistance of the two metals in molten salt 13. It can be seen that the present invention not only realizes the high-temperature halide molten salt 13 corrosion electrochemical test under strict air isolation, but also solves the problem of being unable to perform long-term testing due to evaporation loss of molten salt 13.

[0094] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An atmosphere-controlled halide molten salt corrosion long-term electrochemical testing device, characterized in that: include: Atmosphere control components, used to provide and maintain the atmosphere; An airtight assembly, comprising a pipe sealing joint (24), for forming a sealed environment for the atmosphere control assembly; Heating assembly, used for heating the atmosphere control assembly; A measuring component, which penetrates the airtight component and is located in the atmosphere control component, and is used to monitor and record electrochemical signals in the molten salt (13) environment; A heat insulation component, which is located in the atmosphere control component and is used to prevent heat from dissipating; The impurity treatment component is connected to the atmosphere control component and is used to remove impurities and by-products released during the test process.

2. The atmosphere-controlled long-term electrochemical test device for halide molten salt corrosion according to claim 1, characterized in that: The atmosphere control component comprises an airtight container (17) and a high-pressure gas cylinder (16); a crucible (10) is arranged inside the airtight container (17); a molten salt (13) is arranged inside the crucible (10); a crucible cover (18) is arranged at the opening of the crucible (10); a flange cover (21) is installed at the opening of the airtight container (17); the pipe sealing joint (24) is installed on the top surface of the flange cover (21); the high-pressure gas cylinder (16) is connected to the air inlet pipe (23); and an air inlet valve (22) is installed in the middle of the air inlet pipe (23).

3. The atmosphere-controlled long-term electrochemical test device for halide molten salt corrosion according to claim 2, characterized in that: The insulation assembly comprises a first insulation brick (19) and a second insulation brick (20), wherein the second insulation brick (20) is located at the top of the airtight container (17), and the first insulation brick (19) is located in the middle of the airtight container (17), and the first insulation brick (19) and the second insulation brick (20) are connected by bolts and nuts.

4. The atmosphere-controlled long-term electrochemical test device for halide molten salt corrosion according to claim 3, characterized in that: The measuring assembly comprises a working electrode (15), a reference electrode (14), a counter electrode (12) and an armored thermocouple (11), and all three are connected to an electrochemical workstation (1), and the counter electrode (12), the reference electrode (14) and the working electrode (15) are all located inside the molten salt (13); The impurity treatment component comprises an air outlet main pipe (2), a vacuum pump (5), a second air outlet branch pipe (7) and a solution tank (8); the two ends of the air outlet main pipe (2) are respectively connected to an airtight container (17) and a first air outlet branch pipe (3); the first air outlet branch pipe (3) is connected to the vacuum pump (5); a vacuum valve (4) is installed in the middle of the first air outlet branch pipe (3); the middle of the air outlet main pipe (2) is connected to the second air outlet branch pipe (7); one side of the second air outlet branch pipe (7) is located inside the treatment liquid in the solution tank (8); and an air outlet valve (6) is installed in the middle of the second air outlet branch pipe (7).

5. The atmosphere-controlled long-term electrochemical test device for halide molten salt corrosion according to claim 4, characterized in that: The pipe sealing joint (24) comprises a hollow stud (25), a hollow nut (26) and a hollow conical washer (27); the hollow stud (25) is fixedly connected to the top surface of the flange cover (21); the hollow nut (26) is threadedly connected to the top of the outer wall of the hollow stud (25); the hollow conical washer (27) is located between the hollow nut (26) and the hollow stud (25); a through hole is opened in the middle of the flange cover (21); the hollow stud (25) is coaxial with the through hole; The gas outlet main pipe (2) passes through the hollow stud (25), the through hole and the second heat insulating brick (20) in sequence, and its end is located between the second heat insulating brick (20) and the first heat insulating brick (19); The working electrode (15), the reference electrode (14), the counter electrode (12) and the armored thermocouple (11) are all sequentially passed through the hollow stud (25), the through hole and the second insulation brick (20), the first insulation brick (19) and the crucible cover (18) and then placed in the molten salt (13); The air inlet pipe (23) sequentially passes through the hollow stud (25), the through hole, the second insulation brick (20) and the first insulation brick (19), and is located between the outer wall of the crucible (10) and the inner wall of the airtight container (17).

6. The atmosphere-controlled long-term electrochemical test device for halide molten salt corrosion according to claim 2, characterized in that: The heating component comprises a high-temperature furnace (9), and the airtight container (17) is located inside the high-temperature furnace (9).

7. A method for long-term electrochemical testing of halide molten salt corrosion with controlled atmosphere, based on a device for long-term electrochemical testing of halide molten salt corrosion with controlled atmosphere according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Packaging electrodes and molten salt (13): All operations in this step were performed in a glove box filled with argon or vacuum; The prepared molten salt (13) is placed in the crucible (10), and the crucible cover (18) is connected to the crucible (10) by means of threads; three electrodes and an armored thermocouple (11) are respectively inserted into the through holes on the crucible cover (18) until the three electrodes and the armored thermocouple (11) are located in the middle of the crucible (10); Step 2: Assembly and atmosphere control: The packaged crucible (10) is placed in an airtight container (17), and the first insulation brick (19), the second insulation brick (20), the flange cover (21), the hollow conical gasket (27) and the hollow nut (26) are sequentially passed through the three electrodes and the armored thermocouple (11), and then the first insulation brick (19), the second insulation brick (20) and the flange cover (21) are sequentially installed, and then the air inlet pipe (23) and the air outlet main pipe (2) are sequentially passed through the pipe sealing joint (24) into the airtight container (17), and finally the hollow nut (26) is rotated to press the hollow conical gasket (27); Step 3, then close the air inlet valve (22) and the air outlet valve (6), open the vacuum valve (4), and start the vacuum pump (5) to draw a vacuum; after completion, close the vacuum pump (5) and the vacuum valve (4), and open the air inlet valve (22) to allow the argon gas to fill the airtight container (17); Step 4: Temperature rise and stability test: The air inlet valve (22) and the vacuum valve (4) are closed, the air outlet valve (6) is opened, and the high temperature furnace (9) is driven to start heating; When the temperature reaches 700-750° C., the three electrodes are connected to the electrochemical workstation (1) to measure the change of the open circuit potential of the system by using the open circuit potential method; Step 5: Start the test: Start the test when the open circuit potential in step 4 reaches stability.

8. The atmosphere-controlled long-term electrochemical test method for halide molten salt corrosion according to claim 7, characterized in that: In the step 1, the counter electrode (12), the reference electrode (14), the working electrode (15), the armored thermocouple (11) and the crucible cover (18) are all in a vertical state, and high-temperature glue is used to seal the through hole and the gaps between the three electrodes and the armored thermocouple (11), and the high-temperature glue is cured for standby use.

9. The atmosphere-controlled long-term electrochemical test method for halide molten salt corrosion according to claim 7, characterized in that: In the step 2, when the vacuum is drawn, the vacuum degree in the airtight container (17) is less than 1×10 3 When the pressure drops below Pascal, the vacuum pump (5) and the vacuum valve (4) are closed.

10. The atmosphere-controlled long-term electrochemical test method for halide molten salt corrosion according to claim 7, characterized in that: In the step 3, step 3 is repeated 3 to 4 times to fill the airtight container (17) with argon gas.

Images