Electrochemical testing device and method for simulating hydrofluoric acid steam environment
By designing an electrochemical test device that simulates the hydrofluoric acid steam environment, combined with micro-scale electrochemical testing technology, the problem that the existing technology is difficult to capture the complex corrosion process in the HF steam environment is solved, and the accurate detection and analysis of the corrosion behavior of the material is achieved, filling the technical gap.
Patent Information
- Application Number
- CN202510254117.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-05
- Publication Date
- 2025-07-01
AI Technical Summary
Existing electrochemical testing methods are difficult to effectively capture the complex corrosion processes in the HF steam environment, especially the lack of accurate detection methods for electrochemical reactions at the droplet scale, which leads to huge challenges in the research on the corrosion of HF steam on materials.
An electrochemical test device that simulates the hydrofluoric acid steam environment is designed, including an HF solution tank, a fixed bracket, a fine-tuned precision lifting platform and an electrochemical workstation. A stable HF steam environment is generated through the HF solution, and a dynamic thin liquid film is formed on the surface of the sample. Combined with micro-scale electrochemical testing technology, it can achieve accurate detection of the corrosion behavior of materials in the HF steam environment.
The device can truly simulate the corrosion conditions in the HF steam environment, support time-resolved impedance spectroscopy test and polarization test at different scanning rates, capture the dynamic corrosion process of materials in real time, provide key data for the study of non-steady-state corrosion behavior, and fill the technical gap in microdroplet corrosion behavior detection in the HF steam environment.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of material corrosion performance testing, and particularly relates to an electrochemical testing device and method for simulating a hydrofluoric acid vapor environment. Background Art
[0002] Hydrogen fluoride (HF) is a core raw material in the fluorochemical industry and is widely used in multiple fields such as fine chemicals, metallurgy, pharmaceuticals, and material processing. Although HF has important application value in industry, its extremely strong corrosiveness and volatility bring significant risks during its use and storage. HF vapor is formed by the volatilization of HF liquid and its combination with water vapor in the environment, and this vapor environment also has strong corrosiveness. Especially under high-temperature and high-humidity conditions, the erosion rate and degree of HF vapor on metals, alloys, and other materials far exceed those of conventional corrosive media. The corrosion behavior of HF vapor has certain similarities with atmospheric corrosion and belongs to the typical thin liquid film corrosion type.
[0003] In an HF vapor environment, the corrosion process exhibits high non-uniformity and dynamic characteristics. On the one hand, the adsorption and condensation processes of tiny droplets in HF vapor on the metal surface are intermittent and unevenly distributed, resulting in the initial corrosion reaction being mainly concentrated in some local and irregular areas. The adsorption and aggregation processes of these micro-droplets lead to significant spatial heterogeneity at the beginning of the corrosion reaction. On the other hand, the corrosion is usually dominated by a very thin electrolyte layer, which continuously grows during the process of continuously adsorbing moisture and corrosion products, forming a dynamically changing corrosion environment. Therefore, the corrosion process in HF vapor has strong non-steady-state characteristics, and the corrosion rate changes continuously with time and environmental conditions.
[0004] Due to the extremely strong corrosiveness of HF vapor and the complex and changeable behavior of micro-droplets, the electrochemical corrosion process in HF vapor has not been fully understood, and its monitoring technology lags behind. Existing electrochemical testing methods are difficult to effectively capture the complex corrosion process in an HF vapor environment, especially the electrochemical reactions at the micro-droplet scale still lack precise detection means. The current technical bottleneck makes the corrosion research in an HF vapor environment face great challenges.
[0005] Therefore, there is an urgent need to develop an efficient and precise electrochemical testing platform, especially an innovative testing technology that can simulate and analyze the corrosion behavior in an HF vapor environment at the microscale, to cope with the severe corrosion impact of HF vapor on materials and promote in-depth research on related corrosion mechanisms. Summary of the Invention
[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an electrochemical testing device and method for simulating a hydrofluoric acid vapor environment.
[0007] The technical problem solved by the present invention is achieved through the following technical solutions:
[0008] An electrochemical test device under a simulated hydrofluoric acid vapor environment, characterized in that: it includes an HF solution tank, a fixed bracket, a fine-tuning precision lifting table and an electrochemical workstation. A sample is inserted through an opening on the side of the HF solution tank, an HF solution is placed in the HF solution tank, and an HF thin liquid film is formed on the surface of the sample. The end of the fixed bracket is connected to the fine-tuning precision lifting table, a Pt electrode is installed at the end of the fine-tuning precision lifting table, and both the Pt electrode and the sample are connected to the electrochemical workstation. The fine-tuning precision lifting table drives the Pt electrode to move vertically back and forth to contact the HF thin liquid film and the sample.
[0009] Moreover, the HF solution tank is made of polytetrafluoroethylene material.
[0010] Moreover, the opening on the side of the HF solution tank is sealed with a plastic film and plastic sealing clay.
[0011] An electrochemical test method under a simulated hydrofluoric acid vapor environment, characterized in that: the above-mentioned electrochemical test device is adopted, and the steps of the method are as follows:
[0012] S1. Add 50 ml of HF solution to the HF solution tank and let it stand for 5 min to form a natural and stable HF vapor environment;
[0013] S2. After grinding and polishing the sample, insert it into the opening of the HF solution tank, and an HF thin liquid film is formed on the surface of the sample;
[0014] S3. Start and adjust the fine-tuning precision lifting table to drive the Pt electrode to move slowly downward, and record the initial electrical signal of the electrochemical workstation at the same time;
[0015] S4. The fine-tuning precision lifting table continues to move downward so that the Pt electrode contacts the surface of the HF thin liquid film. At this time, the current signal jumps significantly. Stop rotating the fine-tuning precision lifting table and record the differential head scale value of the micrometer of the fine-tuning precision lifting table; continue to slowly rotate the lifting table until the Pt electrode contacts the surface of the sample. At this time, the current signal jumps again, and record the differential head scale value again. The difference between the two scale values is the droplet thickness of the HF thin liquid film. Adjust the fine-tuning precision lifting table according to this droplet thickness value to ensure that the Pt electrode stays at the middle position of the HF thin liquid film;
[0016] S5. Use the electrochemical test device to complete the impedance spectrum test of the sample over time and the polarization test at different scanning rates to obtain test curves, and analyze the material corrosion behavior in the HF vapor environment according to the test curves.
[0017] Moreover, the mass fraction of the HF solution is 40%, and the grinding and polishing treatment uses a 1-μm grinding paste.
[0018] The advantages and beneficial effects of the present invention are as follows:
[0019] 1. Real environment simulation: By using the HF solution to generate a stable HF vapor environment and forming a dynamic thin liquid film on the surface of the specimen, it highly restores the corrosion conditions of HF vapor in the real industrial scenario (such as the corrosion behavior of the thin liquid film under high-temperature and high-humidity environments), solving the problem that it is difficult to simulate the microscale corrosion environment by traditional methods.
[0020] 2. Dynamic monitoring and analysis ability: It supports time-resolved impedance spectroscopy testing and polarization testing at different scanning rates, and can capture the dynamic corrosion process of materials in the HF vapor environment in real time (such as liquid film growth and local corrosion evolution), providing key data for the study of non-steady-state corrosion behavior.
[0021] 3. Technical innovation: For the first time, a linkage mechanism of liquid film thickness measurement and electrode positioning is proposed, combined with microscale electrochemical testing technology, filling the technical gap in the detection of microdroplet corrosion behavior in the HF vapor environment and providing a new platform for the study of complex corrosion mechanisms.
[0022] 4. Wide application value: By accurately analyzing the corrosion rate, impedance characteristics, and polarization behavior of materials in HF vapor, it can guide the development and optimization of HF corrosion-resistant materials (such as alloys and coatings), helping to upgrade the equipment protection technology in high-risk industries such as chemical engineering and metallurgy. Brief Description of the Drawings
[0023] Figure 1 is a schematic structural diagram of the device of the present invention;
[0024] Figure 2 is a potential curve graph for testing the thickness of the HF thin liquid film droplet of the present invention;
[0025] Figure 3 a) is a polarization curve test graph of SS 316L of the present invention in the HF vapor environment; Figure 3 b) is an impedance spectroscopy test curve graph of SS 316L of the present invention in the HF vapor environment.
[0026] Figure 4 a) is a polarization curve test graph of IN625 of the present invention in the HF vapor environment; Figure 4 b) is an impedance spectroscopy test curve graph of IN625 of the present invention in the HF vapor environment. Detailed Embodiments
[0027] The present invention will be further described in detail below through specific embodiments. The following embodiments are only descriptive and not restrictive, and the protection scope of the present invention cannot be limited thereby.
[0028] As shown Figure 1 in the figure, an electrochemical testing device under a simulated hydrofluoric acid vapor environment is characterized in that: it includes an HF solution tank, a fixed bracket, a fine-tuning precision lifting table and an electrochemical workstation. A sample is inserted through an opening on the side of the HF solution tank. In this embodiment, two types of samples, SS 316L and IN625, are selected, which have completely different corrosion rates and corrosion behaviors in the HF vapor environment, so as to verify the reliability and effectiveness of the test results of this device. HF solution is placed in the HF solution tank, and the HF solution forms an HF thin liquid film on the surface of the sample. The end of the fixed bracket is connected to the fine-tuning precision lifting table, and a Pt electrode is installed at the end of the fine-tuning precision lifting table. Both the Pt electrode and the sample are connected to the electrochemical workstation. The fine-tuning precision lifting table drives the Pt electrode to move vertically back and forth to contact the HF thin liquid film and the sample.
[0029] The HF solution tank is made of polytetrafluoroethylene material to ensure the corrosion resistance of the solution tank.
[0030] The opening on the side of the HF solution tank is sealed with plastic film and plastic sealing clay to prevent HF vapor leakage and ensure the safety of the testing device.
[0031] An electrochemical testing method under a simulated hydrofluoric acid vapor environment is characterized in that: the above-mentioned electrochemical testing device is adopted, and the steps of the method are as follows:
[0032] S1. Add 50 ml of HF solution with a mass fraction of 40% to the HF solution tank and let it stand for 5 minutes to form a natural and stable HF vapor environment;
[0033] S2. After the sample is polished with 1 um abrasive paste, it is inserted into the opening of the HF solution tank, and an HF thin liquid film is formed on the surface of the sample;
[0034] S3. Start and adjust the fine-tuning precision lifting table to drive the Pt electrode to move slowly downward, and record the initial electrical signal of the electrochemical workstation at the same time;
[0035] S4. The fine-tuning precision lifting table continues to move downward so that the Pt electrode contacts the surface of the HF thin liquid film. At this time, the current signal jumps significantly. Stop rotating the fine-tuning precision lifting table and record the differential head scale value of the micrometer of the fine-tuning precision lifting table; continue to slowly rotate the lifting table until the Pt electrode contacts the surface of the sample. At this time, the current signal jumps again, and record the differential head scale value again. The difference between the two scale values is the droplet thickness of the HF thin liquid film. At the same time, record the test potential curve graph of the HF thin liquid film droplet thickness, as Figure 2 shown; adjust the fine-tuning precision lifting table according to the droplet thickness value to ensure that the Pt electrode stays at the middle position of the HF thin liquid film;
[0036] S5. Use an electrochemical testing device to complete the impedance spectrum test of the specimen over time and the polarization test at different scanning rates, and obtain the test curves, as Figure 3 and 4 shown. Analyze the corrosion behavior of the material in the HF vapor environment based on the test curves. Compare the polarization curves of SS 316L and IN625: At different scanning rates, the curve shapes show no significant differences, and there is almost no obvious passivation region in the anodic region. The fast sweep potential is lower, indicating that the passivation film is broken down and dissolved, and HF contacts the metal surface (crack tip). The difference in corrosion potential between the fast sweep and slow sweep of SS 316L is greater, indicating that the accumulation of corrosion products on the surface of SS 316L is more obvious; the corrosion current increases (1.71×10 -7 ~8.37×10 -7 ), indicating that the accumulation of corrosion products cannot hinder the corrosion process, but instead promotes the reaction and accelerates the further corrosion of HF. Compare the impedance spectra of SS 316L and IN625: The capacitive reactance arc of SS 316L gradually becomes smaller with the increase of time, indicating that with the continuous accumulation of the corrosion product layer, it does not play a protective role on the metal surface, and HF still continuously reacts with the material. The lower Rct2 also indicates that the SS 316L material has poor corrosion resistance to HF. The capacitive reactance arc of IN625 continuously becomes larger with the increase of time, indicating that it plays a protective role on the material and hinders the reaction between HF and the material. The larger capacitive reactance arc also indicates that the IN625 material has better corrosion resistance to HF.
[0037] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art can understand that: without departing from the spirit and scope of the present invention and the appended claims, various substitutions, changes, and modifications are possible. Therefore, the scope of the present invention is not limited to the content disclosed in the embodiments and drawings.
Claims
1. An electrochemical testing device in a simulated hydrofluoric acid vapor environment, characterized in that: It comprises an HF solution box, a fixed support, a fine-tuning precision lifting platform and an electrochemical workstation, wherein a hole is opened on the side of the HF solution box to insert a sample, an HF solution is placed in the HF solution box, and the HF solution forms an HF thin liquid film on the surface of the sample, the end of the fixed support is connected to the fine-tuning precision lifting platform, a Pt electrode is installed at the end of the fine-tuning precision lifting platform, the Pt electrode and the sample are both connected to the electrochemical workstation, and the fine-tuning precision lifting platform drives the Pt electrode to reciprocate vertically to contact the HF thin liquid film and the sample.
2. The electrochemical testing device in a simulated hydrofluoric acid vapor environment according to claim 1, characterized in that: The HF solution tank is made of polytetrafluoroethylene material.
3. The electrochemical testing device in a simulated hydrofluoric acid vapor environment according to claim 1, characterized in that: The side openings of the HF solution box are sealed with plastic film and plastic sealant.
4. An electrochemical testing method in a simulated hydrofluoric acid vapor environment, characterized in that: Using the electrochemical testing device according to any one of claims 1 to 3, the steps of the method are: S1. Add 50 ml of HF solution into the HF solution tank and let it stand for 5 minutes to form a natural and stable HF vapor environment; S2, inserting the sample into the opening of the HF solution box after grinding and polishing, and forming a thin HF liquid film on the surface of the sample; S3, start and adjust the fine-tuning precision lifting platform to drive the Pt electrode to move slowly downward, and record the initial electrical signal of the electrochemical workstation at the same time; S4, the fine-tuning precision lifting platform continues to move downward so that the Pt electrode contacts the surface of the HF thin liquid film. At this time, the current signal jumps significantly. Stop rotating the fine-tuning precision lifting platform and record the differential head scale value of the micrometer of the fine-tuning precision lifting platform; continue to slowly rotate the lifting platform until the Pt electrode contacts the surface of the sample. At this time, the current signal jumps again and the differential head scale value is recorded again. The difference between the two scale values is the droplet thickness of the HF thin liquid film. According to the droplet thickness value, adjust the fine-tuning precision lifting platform to ensure that the Pt electrode stays in the middle position of the HF thin liquid film; S5. Use an electrochemical testing device to complete the impedance spectrum test of the sample over time and the polarization test at different scanning rates and obtain the test curve. According to the test curve, analyze the corrosion behavior of the material in the HF vapor environment.
5. The electrochemical test and method in a simulated hydrofluoric acid vapor environment according to claim 1, characterized in that: The mass fraction of the HF solution is 40%, and the grinding and polishing process uses a 1 um grinding paste.