An electrochemical corrosion sample for harsh environments and a method of preparing the same

Abstract

The present application relates to spent fuel reprocessing corrosion electrochemistry field, specifically a kind of electrochemical corrosion sample and its preparation method for harsh environment.The sample adopts the cylinder with one end as hemisphere, hole is opened in the center of the flat end surface of sample, inner thread I is arranged in hole, the side of the inner thread I of sample is fastened with the one end of connecting screw rod by thread, the gasket I with enhanced sealing is arranged at the connecting place of sample and connecting screw rod;The other end of connecting screw rod is fastened with bolt by thread, the gasket II with enhanced sealing is arranged at the connecting place of connecting screw rod and bolt;A glass tube is additionally sleeved on connecting screw rod, one end of glass tube is tightly pressed on gasket I, the other end of glass tube is tightly pressed on gasket II.The present application can be suitable for preparing electrochemical sample needing to work in harsh environment, study electrochemical corrosion behavior of material in harsh environment, can effectively avoid the situation that the sample prepared by existing electrochemical sample preparation method is destroyed by electrolyte solution.

Description

Technical Field

[0001] This invention relates to the field of spent fuel reprocessing corrosion electrochemistry, specifically to an electrochemical corrosion sample for use in harsh environments and its preparation method. Background Technology

[0002] The typical environment for spent fuel reprocessing is characterized by high temperature, high acidity, and strong oxidizing properties. Key reprocessing equipment, such as dissolvers and various evaporators, operates under these extremely harsh conditions for extended periods, leading to severe corrosion of materials. The corrosion damage to alloys seriously threatens the safe operation of the equipment. Therefore, research on the corrosion behavior of equipment materials in high-temperature nitric acid media is crucial. However, existing electrochemical corrosion sample preparation methods have drawbacks, resulting in sample destruction and affecting experimental results. Our goal is to develop a durable, durable, and easily destroyed electrochemical corrosion sample suitable for various and variable working environments under harsh conditions. By applying this sample to electrochemical corrosion experiments on key equipment materials and combining the electrochemical test results with other experimental results and product analysis, we can systematically elucidate the corrosion behavior of various materials in different media, providing theoretical support for related research and theoretical guidance for equipment material selection and the development of new materials. Summary of the Invention

[0003] The purpose of this invention is to provide an electrochemical corrosion sample for use in harsh environments and a method for preparing the same sample, which solves the problems of complex processes in existing electrochemical corrosion sample preparation methods and the frequent occurrence of nitric acid leakage that damages the sample. At the same time, the sample is easy to disassemble and replace. When replacing a sample after testing the same type of sample, only a specially made sample needs to be replaced, which can shorten the sample replacement time and save the amount of preparation materials and sample materials used.

[0004] The technical solution of this invention is:

[0005] An electrochemically corroded sample for use in harsh environments, comprising a sample, gasket I, connecting screw, glass tube, gasket II, and bolts, with the following specific structure:

[0006] The sample is a cylinder with one hemispherical end. A hole is made in the center of the flat end face of the sample, and an internal thread I is provided in the hole. The side of the sample with internal thread I is fastened to one end of the connecting screw by the thread. A gasket I is provided at the connection between the sample and the connecting screw to enhance the sealing. The other end of the connecting screw is fastened to the bolt by the thread. A gasket II is provided at the connection between the connecting screw and the bolt to enhance the sealing. A glass tube is added to the outside of the connecting screw. One end of the glass tube is pressed tightly against the gasket I, and the other end of the glass tube is pressed tightly against the gasket II.

[0007] One end of the bolt is a stud with external threads, which is fastened to the connecting screw by the threads. The other end of the bolt is a cylindrical terminal, through which the wire is connected to the sample.

[0008] The glass tube is wrapped around the connecting screw. One end of the connecting screw is fastened to the stud of the bolt by the helical movement of the bolt, and the other end of the connecting screw is fastened to one side of the sample by the helical movement of the sample. Under the action of the threaded fastening at both ends, the glass tube is pressed against the gaskets at both ends, achieving a secondary seal for the sample.

[0009] The electrochemical corrosion sample for harsh environments has an appearance similar to the bullet head of a round-nosed bullet. The sample body is cylindrical with one end being hemispherical. The other end of the sample body has a circular hole along the axial direction and an internal thread I is provided in the circular hole. The side where the internal thread I is located is fastened to the connecting screw through the thread. The glass tube and gasket I are compressed by the fastening of the sample and the connecting screw.

[0010] The electrochemical corrosion sample for harsh environments has a connecting screw with a cylindrical body. One end of the connecting screw body has a circular hole along the axial direction and an internal thread II is provided in the circular hole. The internal thread II is fastened to the bolt by the thread. The glass tube and gasket II are compressed by the fastening of the connecting screw and the bolt. The other end of the connecting screw body has an external thread with a diameter equal to the diameter of the internal thread I of the sample.

[0011] The aforementioned electrochemical corrosion sample for harsh environments consists of a bolt composed of a stud, a bolt head, and a round bar with a protruding end, which are coaxially connected as a terminal block. The thread diameter of the stud is equal to the diameter of the internal thread II on the connecting rod. During the electrochemical testing experiment, the electrode connection wire of the electrochemical workstation is fixed to the terminal block with an alligator clip. The stud of the bolt is fastened to one end of the connecting rod by the thread, while simultaneously pressing the glass tube and the gasket II at this location.

[0012] The electrochemical corrosion sample for harsh environments has a bolt head that is cylindrical or hexagonal prism shaped, wherein: when the bolt head is cylindrical, the bolt head diameter is equal to the outer diameter of the glass tube; when the bolt head is hexagonal prism, the length of the opposite sides of the hexagonal bolt head is equal to the outer diameter of the glass tube.

[0013] The electrochemical corrosion sample used in harsh environments has a column length of 5-10 mm, a bolt head thickness of 1-5 mm, and a terminal block that is a cylinder with a length of 5-20 mm and a diameter of 1-3 mm.

[0014] The electrochemical corrosion sample used in harsh environments has an inner diameter of gasket I equal to the diameter of the internal thread I of the sample, an inner diameter of gasket II equal to the diameter of the internal thread II of the connecting screw, and an outer diameter of gasket I and gasket II greater than or equal to the diameter of the glass tube. Gasket I and gasket II are used at the connection between the bolt and the glass tube and the connecting screw, and at the connection between the sample and the glass tube and the connecting screw, respectively.

[0015] The electrochemical corrosion sample used in harsh environments is made of the same material as the connecting screw. The bolt is made of copper, silver, aluminum or tungsten with good conductivity, and gaskets I and II are made of polytetrafluoroethylene.

[0016] The method for preparing electrochemical corrosion samples for harsh environments involves first fixing the sample, gasket I, and connecting screw together, and then tightening the internal thread I of the sample to the external thread of the connecting screw. Next, the connecting screw is passed through a glass tube, and the stud of the bolt is tightened to the internal thread II of the connecting screw. For electrochemical experiments, the prepared sample is fitted with an electrode sealing ring, inserted into the electrode hole, and the sealing bolt of the electrolytic cell is tightened. The alligator clips of the electrode connection cable of the electrochemical workstation are fixed to the terminal block. When conducting parallel tests on one sample or tests under multiple conditions, the electrochemical corrosion sample is removed, unscrewed, and replaced with a new sample.

[0017] The method for preparing electrochemical corrosion samples under harsh environments involves a glass tube surrounding a connecting screw to seal the connecting screw. The connecting screw, bolt, and sample are fastened together by threads. The glass tube is tightly connected to gaskets I and II to complete a secondary seal for the sample.

[0018] The design concept of this invention is:

[0019] This invention addresses a real-world engineering problem: during spent fuel reprocessing, some critical equipment operates under extreme and variable conditions for extended periods, leading to severe material corrosion that threatens the safe operation of the equipment. To systematically elucidate the corrosion behavior of various materials in different media, electrochemical corrosion testing is indispensable. However, existing electrochemical corrosion sample preparation methods have some drawbacks. Therefore, this invention aims to develop a new method to effectively overcome these shortcomings, protect the sample from damage, and effectively shorten sample changeover time, while also saving on the amount of preparation and sample materials used.

[0020] In this invention, the sample is made into a bullet-shaped form similar to a round-nosed bullet. The sample is connected to a bolt with a terminal on the head via a connecting screw. The sample is electrochemically etched and sealed with a glass tube. During the electrochemical testing experiment, the electrochemical workstation transmits electrochemical signals by connecting to the terminal on the sample.

[0021] Limited materials can be used long-term in boiling nitric acid. From the perspectives of long-term use and safety, glass tubes were chosen as the sealing device for the samples, with the tubes being as thick as possible to prevent accidental breakage. To facilitate connection of the samples to the electrochemical workstation, specially designed bolts were fitted with terminals. Copper was chosen as the material for these bolts because of its excellent conductivity and good machinability. To protect the samples, gaskets were placed at the joints of various sample components to enhance sealing. However, ethylene oxide as a gasket would be toxic, so polytetrafluoroethylene (PTFE), a harmless material to humans, was selected. During use, the connecting threads must be tightened to create a sealed space to protect the samples.

[0022] For energy conservation and environmental protection purposes, the overall sample size is small. The sample preparation process does not require energy-intensive welding, sintering and high-temperature heating steps. When conducting parallel tests or tests under multiple conditions, only the specially made sample needs to be replaced.

[0023] To prevent nitric acid leakage from damaging the sample, the connecting screw is made of the same material as the sample being tested. Even if a small amount of nitric acid enters the glass tube, it will not affect the test results, and the sample can be reused after cleaning or replacing the parts.

[0024] The present invention has the following advantages and beneficial effects:

[0025] 1. The polytetrafluoroethylene, copper, and glass materials used in this invention all have good biocompatibility, are harmless to the human body, and have high safety.

[0026] 2. Each part of the electrochemical sample designed in this invention can be easily disassembled and installed, making sample replacement more convenient.

[0027] 3. The electrochemical sample designed in this invention is fastened with threads between its various parts. When conducting parallel tests of a single sample or tests under multiple conditions, only the specially made sample needs to be replaced.

[0028] 4. The polytetrafluoroethylene gasket and glass tube in this invention are resistant to acids and alkalis and high temperatures, and can be used in various corrosive working conditions. The slight expansion generated under high temperature conditions will strengthen the fastening between the parts.

[0029] 5. The electrochemical sample designed in this invention has a small size, and the sample preparation process does not require energy-intensive welding, sintering and high-temperature heating steps. In addition, multiple specially made samples can be replaced, and the cost is controlled without affecting the use of the samples, which has high economic benefits.

[0030] 6. The size of the electrochemical sample designed in this invention is relatively flexible and can be adjusted according to different experimental needs.

[0031] 7. This invention is applicable to the preparation of electrochemical samples that need to work in harsh environments and the study of the electrochemical corrosion behavior of materials under harsh environments. It can effectively avoid the situation where electrolyte solutions damage the samples obtained by existing electrochemical sample preparation methods. It can work for a long time in strong acid, strong alkaline and high temperature and high pressure environments, increasing the reliability of experimental data obtained from electrochemical tests. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the main structure of the electrochemical corrosion sample of the present invention.

[0033] Figure 2 This is a schematic diagram of a specially made sample for this invention.

[0034] Figure 3 This is a schematic diagram of the connecting screw of the present invention.

[0035] Figure 4 This is a schematic diagram of the specially designed bolt for this invention.

[0036] Figure 5 This is a schematic diagram of the decomposed structure of the electrochemically corroded sample of the present invention.

[0037] In the figure: 1. Sample; 2. Gasket I; 3. Connecting screw; 4. Glass tube; 5. Gasket II; 6. Bolt; 7. Hemisphere; 8. Sample body; 9. Internal thread I; 10. External thread; 11. Connecting screw body; 12. Internal thread II; 13. Stud; 14. Bolt head; 15. Terminal. Detailed Implementation

[0038] like Figures 1-5 As shown, this invention designs an electrochemical corrosion sample for use in harsh environments. The electrochemical corrosion sample includes sample 1, gasket I2, connecting screw 3, glass tube 4, gasket II5, and bolt 6, with the specific structure as follows:

[0039] Sample 1 is shaped like a bullet, similar to a round-nosed bullet. This shape is beneficial for more uniform electrochemical signal transmission. Other shapes that facilitate electrochemical signal transmission can be made if needed for the experiment. A hole is made in the center of the flat end face of Sample 1, with an internal thread I9 inside. The side of Sample 1 with the internal thread I9 is ​​threadedly fastened to one end of the connecting screw 3. A gasket I2 is provided at the connection between Sample 1 and the connecting screw 3 to enhance sealing. The other end of the connecting screw 3 is threadedly fastened to the bolt 6. A gasket II5 is provided at the connection between the connecting screw 3 and the bolt 6 to enhance sealing. A glass tube 4 is fitted over the connecting screw 3, with one end of the glass tube 4 pressed tightly against the gasket I2 and the other end pressed tightly against the gasket II5.

[0040] One end of the bolt 6 is a stud 13 with external threads, which is fastened to the connecting screw 3 by the threads. The other end of the bolt 6 is a cylindrical terminal 15, through which the wire is connected to the sample 1.

[0041] The glass tube 4 surrounds the connecting screw 3. One end of the connecting screw 3 is fastened to the stud 13 of the bolt 6 by the helical movement of the bolt 6, and the other end of the connecting screw 3 is fastened to one side of the sample 1 by the helical movement of the sample 1. Under the action of the threaded fastening at both ends, the glass tube 4 is pressed against the gaskets at both ends, thus completing the secondary sealing of the sample.

[0042] like Figure 1 , Figure 2 As shown, Sample 1 and the connecting screw 3 are made of the same material, using a cylinder with one end being a hemisphere, resembling the shape of a round pistol bullet. The length and diameter of Sample 1 can be flexibly adjusted within the allowable range. Sample 1 uses a cylinder as the main body 8, with one end of the main body 8 being a hemisphere 7. The other end of the main body 8 has a circular hole along the axial direction, and an internal thread I9 is ​​provided in the circular hole. The side with the internal thread I9 is ​​fastened to the connecting screw 3 by the thread. The fastening of Sample 1 and the connecting screw 3 compresses the glass tube 4 and the gasket I2, achieving a secondary seal.

[0043] like Figure 1 , Figure 3 As shown, the connecting screw 3 is made of the same material as sample 1. This design allows the sample to continue operating normally without affecting the test results even when facing electrolyte leakage. The connecting screw 3 has a cylindrical body 11. One end of the connecting screw body 11 has a circular hole along the axial direction and an internal thread II12 is provided in the circular hole. Here, the internal thread II12 is fastened to the bolt 6 by the thread. The length and inner diameter of the internal thread II12 can be freely adjusted within the allowable range. The fastening of the connecting screw 3 and the bolt 6 presses the glass tube 4 and the gasket II5 together. The other end of the connecting screw body 11 has an external thread 10, the diameter of which is equal to the diameter of the internal thread I9 of sample 1.

[0044] like Figure 1 , Figure 4As shown, bolt 6 is coaxially and integrally connected by stud 13, bolt head 14, and a protruding round rod as a terminal post 15. It is made of a highly conductive material such as copper, silver, aluminum, or tungsten. The stud 13 is 5–10 mm long, the bolt head 14 is 1–5 mm thick, and the terminal post 15 is a cylinder with a length of 5–20 mm and a diameter of 1–3 mm. The specific dimensions can be flexibly adjusted according to experimental needs. The thread diameter of stud 13 is equal to the diameter of the internal thread II12 on the connecting screw 3. Bolt head 14 can be cylindrical, hexagonal prism, etc. Specifically: if bolt head 14 is cylindrical, its diameter is equal to the outer diameter of glass tube 4; if bolt head 14 is hexagonal prism, the length of its opposite sides is equal to the outer diameter of glass tube 4. During the electrochemical testing experiment, the electrode connection wires of the electrochemical workstation are fixed to the terminal block 15 with alligator clips, and the stud 13 of the bolt 6 is fastened to one end of the connecting screw 3 by threads, while the glass tube 4 and the gasket II5 here are pressed together.

[0045] like Figure 1 , Figure 5 As shown, the glass tube 4 surrounds the connecting screw 3 to seal the connecting screw 3. Since the connecting screw 3 is fastened to the bolt 6 and the sample 1 by threads, the glass tube 4 is tightly connected to the gasket I2 and gasket II5 to complete the secondary sealing of the sample. The length and outer diameter of the glass tube 4 are reasonably adjusted according to the length of the connecting screw 3, and the thickness should not be too small.

[0046] like Figure 1 , Figure 5 As shown, gaskets I2 and II5 are made of polytetrafluoroethylene. The inner diameter of gasket I2 must be equal to the diameter of the internal thread I9 of sample 1, and the inner diameter of gasket II5 must be equal to the diameter of the internal thread II12 of connecting screw 3. The outer diameter of gaskets I2 and II5 must be greater than or equal to the diameter of glass tube 4. Gaskets I2 and II5 are used at the connection between bolt 6 and glass tube 4 and connecting screw 3, and at the connection between sample 1 and glass tube 4 and connecting screw 3, respectively.

[0047] When preparing the sample, first fix sample 1, gasket I2 and connecting screw 3 together, and tighten the internal thread I9 of sample 1 with the external thread 10 of connecting screw 3; then pass connecting screw 3 through glass tube 4, and tighten the stud 13 of bolt 6 with the internal thread II12 of connecting screw 3; when used for electrochemical experiments, put the prepared sample on the electrode sealing ring, insert it into the electrode hole and tighten the sealing bolt of the electrolytic cell, and fix the electrode connection wire alligator clip of the electrochemical workstation on the terminal 15; when conducting parallel tests of one sample or tests under multiple conditions, the electrochemically corroded sample can be taken out and unscrewed to replace it with a new sample.

[0048] The results show that this invention has developed a durable electrochemical corrosion sample suitable for various variable working environments and harsh conditions. By applying this sample to electrochemical corrosion experiments on materials used in critical equipment, and combining the electrochemical test results with other experimental results and product analysis, the corrosion behavior of various materials in different media can be systematically elucidated. This provides theoretical support for related research and theoretical guidance for equipment material selection and the development of new materials.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. An electrochemically corroded sample for use in harsh environments, characterized in that, The electrochemical corrosion sample includes the sample, gasket I, connecting screw, glass tube, gasket II, and bolts, with the following specific structure: The sample is a cylinder with one hemispherical end. A hole is made in the center of the flat end face of the sample, and an internal thread I is provided in the hole. The side of the sample with internal thread I is fastened to one end of the connecting screw by the thread. A gasket I is provided at the connection between the sample and the connecting screw to enhance the sealing. The other end of the connecting screw is fastened to the bolt by the thread. A gasket II is provided at the connection between the connecting screw and the bolt to enhance the sealing. A glass tube is added to the outside of the connecting screw. One end of the glass tube is pressed tightly against the gasket I, and the other end of the glass tube is pressed tightly against the gasket II. One end of the bolt is a stud with external threads, which is fastened to the connecting screw by the threads. The other end of the bolt is a cylindrical terminal, through which the wire is connected to the sample. The glass tube is wrapped around the connecting screw. One end of the connecting screw is fastened to the stud of the bolt by the helical movement of the bolt, and the other end of the connecting screw is fastened to one side of the sample by the helical movement of the sample. Under the action of the threaded fastening at both ends, the glass tube is pressed against the gaskets at both ends, achieving a secondary seal for the sample. The sample has an appearance similar to the shape of a bullet head. The sample body is a cylinder with one end being a hemisphere. The other end of the sample body has a circular hole along the axial direction and an internal thread I is provided in the circular hole. The side where the internal thread I is located is fastened to the connecting screw through the thread. The glass tube and gasket I are compressed by the fastening of the sample and the connecting screw. The connecting screw has a cylindrical body. One end of the connecting screw body has a circular hole along the axial direction and an internal thread II is provided in the circular hole. The internal thread II is fastened to the bolt by the thread. The glass tube and gasket II are pressed by the fastening of the connecting screw and the bolt. The other end of the connecting screw body has an external thread, and the diameter of the external thread is equal to the diameter of the internal thread I of the sample. The sample and the connecting screw are made of the same material. The bolts are made of copper, silver, aluminum or tungsten with good conductivity, and gaskets I and II are made of polytetrafluoroethylene.

2. The electrochemical corrosion sample for harsh environments according to claim 1, characterized in that, The bolt consists of a stud, a bolt head, and a round bar with one protruding end, which are coaxially connected as a terminal block. The thread diameter of the stud is equal to the diameter of the internal thread II on the connecting rod. During the electrochemical test experiment, the electrode connection wire of the electrochemical workstation is fixed to the terminal block by an alligator clip. The stud of the bolt is fastened to one end of the connecting rod by the thread, while pressing the glass tube and the gasket II at this point.

3. The electrochemical corrosion sample for harsh environments according to claim 2, characterized in that, The bolt head is either cylindrical or hexagonal prism-shaped, wherein: when the bolt head is cylindrical, the bolt head diameter is equal to the outer diameter of the glass tube; when the bolt head is hexagonal prism-shaped, the length of the opposite sides of the hexagons of the bolt head is equal to the outer diameter of the glass tube.

4. The electrochemical corrosion sample for harsh environments according to claim 2, characterized in that, The stud length is 5~10mm, the bolt head thickness is 1~5mm, and the terminal is a cylinder with a length of 5~20mm and a diameter of 1~3mm.

5. The electrochemical corrosion sample for harsh environments according to claim 1, characterized in that, The inner diameter of gasket I is equal to the diameter of the internal thread I of the sample, and the inner diameter of gasket II is equal to the diameter of the internal thread II of the connecting screw. The outer diameters of gasket I and gasket II are greater than or equal to the diameter of the glass tube. Gasket I and gasket II are used at the connection between the bolt and the glass tube and the connecting screw, and at the connection between the sample and the glass tube and the connecting screw, respectively.

6. A method for preparing an electrochemically corroded sample under harsh conditions as described in any one of claims 1 to 5, characterized in that, When preparing the sample, first fix the sample, gasket I, and connecting screw together, and tighten the internal thread I of the sample to the external thread of the connecting screw; then pass the connecting screw through the glass tube, and tighten the stud of the bolt to the internal thread II of the connecting screw; when used for electrochemical experiments, put the prepared sample on the electrode sealing ring, insert it into the electrode hole, and tighten the sealing bolt of the electrolytic cell; fix the electrode connection cable of the electrochemical workstation to the terminal block with the alligator clip; when conducting parallel tests of one sample or tests under multiple conditions, after removing the electrochemically corroded sample, unscrew the sample and replace it with a new sample; The glass tube surrounds the connecting screw, sealing the connecting screw. The connecting screw, bolt, and sample are fastened together by threads. The glass tube is tightly connected to gaskets I and II, completing a secondary seal for the sample.

Images