Atmospheric corrosion electrochemical measurement device and method for simulating metal conductor under autogenous electric field

Abstract

The invention relates to an atmospheric corrosion electrochemical measurement device and method for simulating a metal conductor under a self-source electric field, and the device comprises a self-source electric field system which comprises a grounded tubular metal negative electrode, and a constant-voltage power supply which is connected with the metal conductor and the tubular metal negative electrode; the support is configured to fixedly support a metal conductor serving as a tested sample and the tubular metal negative electrode, and the metal conductor is coated with an insulating film except for the exposed area of the working electrode; the thin liquid film system comprises a thin liquid film medium which is wound on an insulating film area and a working electrode exposure area on the metal conductor, and the thin liquid film medium is used for providing a target test solution environment for the metal conductor; the three-electrode system comprises a counter electrode and a reference electrode, and the exposed area of the metal conductor is used as a working electrode. According to the invention, atmospheric corrosion thin liquid film electrochemical measurement of different atmospheric environment level parameters can be carried out on electrified conductor metal under various different self-source electric field service conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of corrosion electrochemical testing, and relates to an atmospheric corrosion electrochemical measuring device and method for simulating a metal conductor under a self-generated electric field. Background Art

[0002] The environment that the power transmission conductors of the power grid are exposed to during service is relatively complex. In addition to being affected by temperature, air humidity in the atmosphere, and pollutants in the air, they are also affected by the self-generated electric field generated by the transmission conductors. Through preliminary analysis and screening by power inspection personnel, it was found that the corrosion of the transmission lines in service is quite different from that in the conventional atmospheric corrosion environment in terms of both the morphology of corrosion products and the corrosion rate. Related studies have shown that the self-generated electric field generated by the conductor in service can accelerate the corrosion of metals. However, most studies focus on the atmospheric corrosion of metals under the action of exogenous electric fields, that is, the corrosion of metals under the action of external electric fields. Therefore, further research on the atmospheric corrosion mechanism and test methods of metals under the action of self-generated electric fields is of great significance to the safe operation of power transmission conductors in service.

[0003] In the power transmission and transformation system, a self-generated electric field will be generated on the surface of the metal conductor, which has a great influence on the corrosion of the metal. Atmospheric corrosion tests are usually carried out using salt spray test methods and electrochemical measurement methods. Among them, electrochemical measurement has the advantages of being fast and effective. It can not only obtain the corrosion rate of metal materials in the atmosphere, but also conduct in-depth research on the kinetic mechanism of the atmospheric corrosion process of metals. Electrochemical measurements of atmospheric corrosion are usually carried out using thin liquid film devices. By generating an electrolyte film of a certain thickness on the surface of the metal electrode and establishing a three-electrode system, the kinetics of the initial corrosion process of metals in the atmospheric environment are studied.

[0004] Chinese patent application CN117686416A discloses a thin liquid film experimental device and experimental method for atmospheric corrosion of energized metal conductors, which realizes electrochemical measurement of corrosion of conductors under the self-generated magnetic field generated by energized working conditions by introducing a thin liquid film system, a three-electrode system, a constant temperature system and a constant current power supply system. This device solves the problem of establishing a thin liquid film system and a uniform self-generated magnetic field on the surface of a round rod electrode, but it still cannot meet the research on atmospheric corrosion of metals under the self-generated electric field generated by the service conditions of power grid conductors. Summary of the invention

[0005] The purpose of the present invention is to provide an electrochemical measurement device and method for simulating atmospheric corrosion of metal conductors under a self-generated electric field, which can realize the study of atmospheric corrosion of metal conductors under a self-generated electric field.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The applicant found through research that the traditional thin liquid film electrochemical measurement device cannot meet the requirements of metal atmospheric corrosion research under the self-generated electric field generated by the service conditions of power grid conductors. The main reasons are:

[0008] 1. When the power transmission conductor of the power grid is in service, the conductor surface has a surface self-generated electric field of up to 3000kV / m. In the simulation device, a high and uniform self-generated electric field needs to be generated on the conductor surface. Therefore, round rod-shaped conductor materials need to be introduced as electrodes. The existing device lacks relevant supporting designs for providing a uniform self-generated electric field.

[0009] 2. Due to the introduction of the peripheral negative electrode, the space around the electrode is narrow, and the conventional thin liquid film thickness control system and liquid film thickness maintenance method cannot meet the requirements of the thin liquid film system under the self-source electric field;

[0010] 3. Due to the introduction of the peripheral negative electrode, the space around the electrode is narrow. The conventional three-electrode system and the connection method with the electrochemical workstation will affect the spatial distribution of the self-generated electric field and cannot meet the requirements of the thin liquid film system under the self-generated electric field.

[0011] Based on this, the present invention provides an electrochemical measuring device for simulating atmospheric corrosion of metal conductors under a self-generated electric field, which is used to study the atmospheric corrosion of metal conductors under self-generated electric field conditions. The measuring device comprises:

[0012] A self-generated electric field system comprises a grounded tubular metal cathode and a constant voltage power source whose positive and negative electrodes are respectively connected to the metal conductor and the tubular metal cathode;

[0013] A bracket, configured to fixedly support a metal conductor and a tubular metal negative electrode as a test sample, and to allow the metal conductor to pass through the tubular metal negative electrode in parallel, wherein the metal conductor is also partially coated with an insulating film to prevent the counter electrode and the reference electrode from making electrical contact with the metal conductor;

[0014] A thin liquid film system, comprising a thin liquid film medium having an insulating film region and a working electrode region wound on the metal conductor, the medium being composed of a porous film carrier and an electrolyte, and the thin liquid film medium being used to provide a target test thin liquid film environment for the metal conductor;

[0015] The three-electrode system comprises a counter electrode and a reference electrode respectively wound on the thin liquid film medium of the metal conductor, and an exposed area of ​​the metal conductor in the middle area between the counter electrode and the reference electrode which is not coated with an insulating film as a working electrode.

[0016] Furthermore, the metal conductor is colinear with the central axis of the tubular metal negative electrode.

[0017] Furthermore, the tubular metal negative electrode is a copper negative electrode.

[0018] Furthermore, the metal conductor is in the shape of a round rod.

[0019] Furthermore, the thin liquid film system also includes a sponge soaked with a test solution, which is wrapped around the reference electrode and the counter electrode and connected to the porous film carrier to provide the test solution to the porous film carrier to prevent the volatilization of the electrolyte in the film carrier from causing changes in the thickness of the thin liquid film.

[0020] Furthermore, the thin liquid film medium includes a porous film carrier and a solution adsorbed on the porous film carrier.

[0021] Furthermore, the thickness of the thin liquid film medium is 20-100 μm, which is achieved by adjusting the thickness of the porous film carrier.

[0022] Furthermore, the counter electrode is a platinum wire, and the reference electrode is a silver wire covered with AgCl.

[0023] Furthermore, two counter electrodes are provided, which are respectively located at two ends of the working electrode region to ensure uniform current distribution in the working electrode region.

[0024] In another aspect, the present invention provides an electrochemical measurement method for atmospheric corrosion of a metal conductor under a simulated self-generated electric field, which is implemented based on the measurement device as described above, and the measurement method comprises the following steps:

[0025] (1) Collecting environmental characteristic parameters of the service conditions of the metal conductor and preparing a test solution simulating the service conditions;

[0026] (2) preparing a test sample based on a metal conductor, grinding, polishing and cleaning the surface of the test sample, coating an insulating film on the winding position of the reference electrode and the counter electrode and drying it, leaving an exposed area between the reference electrode and the counter electrode as the working electrode, and fixing the test sample horizontally on a bracket;

[0027] (3) winding a porous film carrier around the reference electrode and the counter electrode of the test sample and the exposed working electrode;

[0028] (4) Wrap the reference electrode and the counter electrode on the porous film carrier in the corresponding area, and then wrap two sponges on the reference electrode and the counter electrode. After completion, add the test solution droplets to the sponge so that the sponge is filled with the test solution, and the porous film carrier is also filled with the test solution through the sponge to form a thin liquid film medium. Then, the reference electrode and the counter electrode are respectively led out through wires and connected to the counter electrode end and the reference electrode end of the potentiostat. The test sample is also led out through wires and connected to the working electrode end of the potentiostat to form a three-electrode system;

[0029] (5) Covering the tubular metal negative electrode of the self-source electric field system around the test sample and the three-electrode system, and fixing the tubular metal negative electrode by a bracket, connecting the test sample to the positive electrode of the constant voltage power supply, and connecting the tubular metal negative electrode to the negative electrode of the constant voltage power supply;

[0030] (6) After the test begins, adjust the voltage of the constant voltage power supply according to the service conditions to obtain the required self-generated electric field;

[0031] (7) Turn on the potentiostat, measure the open circuit potential as needed, perform electrochemical measurement after stabilization, and analyze the electrochemical data to obtain the corrosion rate of the metal conductor under the action of the self-source electric field and the kinetic parameters of the corrosion process.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] (1) Aiming at the technical requirements of the atmospheric corrosion thin liquid film experiment of conductor metal under self-source electric field, the self-source electric field conditions and the thin liquid film conditions of conductor service conditions were constructed;

[0034] (2) Electrochemical measurements of atmospheric corrosion thin liquid films at different self-sourced electric field parameter levels can be performed on current-carrying conductive metals under various self-sourced electric field service environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the structure of the measuring device of the present invention;

[0036] Figure 2 The graph shows the variation of the electric field intensity on the surface of conductor bars with different diameters as a function of the input voltage;

[0037] Figure 3 The graph shows the variation of electric field strength with different shell diameters for conductors with different diameters at 1000V voltage;

[0038] Figure 4 The electric field strength at 2120V in a 10cm diameter tubular grounding shell varies with the diameter of the conductor rod;

[0039] Figure 5 The polarization curves of pure aluminum at different voltages when the thin liquid film is 20 μm;

[0040] Figure 6 This is the corrosion current density diagram of pure aluminum at different voltages when the thin liquid film is 20μm;

[0041] Figure 7 The impedance spectrum of aluminum with different voltages applied when the thin liquid film thickness is 20 μm;

[0042] Figure 8 An equivalent circuit for fitting the atmospheric corrosion electrochemical impedance spectrum of aluminum under applied voltage;

[0043] Fig. 9 is the fitting parameter R of aluminum under applied voltage when the thin liquid film is 20 μm ct Change relationships;

[0044] Description of the markings in the figure:

[0045] 1-insulating film; 2-thin liquid film medium; 3-sponge; 4-platinum wire; 5-silver chloride / silver wire; 6-counter electrode wire; 7-reference electrode wire; 8-tubular metal negative electrode; 9-metal conductor; 10-positive electrode of constant voltage power supply; 11-working electrode end; 12-counter electrode end; 13-reference electrode end; 14-negative electrode of constant voltage power supply; 15-fastening screw; 16-bracket; 17-exposed area of ​​conductor working electrode. DETAILED DESCRIPTION

[0046] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0047] In the following implementation manners or examples, unless otherwise specified, functional components or structures are conventional components or conventional structures used in the art to achieve corresponding functions.

[0048] In order to perform electrochemical measurement of atmospheric corrosion thin liquid film parameters of different environmental levels for conductor metals under self-sourced electric field service, the present invention provides an electrochemical measurement device for atmospheric corrosion of metal conductors 9 for simulating self-sourced electric field, which is used to study the atmospheric corrosion of metal conductors 9 under self-sourced electric field conditions. The measurement device comprises:

[0049] The self-generated electric field system comprises a grounded tubular metal cathode 8, and a constant voltage power source whose positive and negative electrodes are respectively connected to the metal conductor 9 and the tubular metal cathode 8;

[0050] The support 16 is configured to fix and support the metal conductor 9 and the tubular metal negative electrode 8 as the tested sample, and to allow the metal conductor 9 to pass through the tubular metal negative electrode 8 in parallel, and the metal conductor 9 is also coated with an insulating film 1;

[0051] The thin liquid film system comprises a thin liquid film medium 2 having an insulating film 1 region and a working electrode region wound on the metal conductor 9, wherein the thin liquid film medium 2 is used to provide a target test solution environment for the metal conductor 9;

[0052] The three-electrode system includes a counter electrode 4 and a reference electrode 5 respectively wound on a thin liquid film medium 2 at two insulating regions of the metal conductor 9, and an exposed region 17 of the metal conductor 9 not coated with an insulating film between the reference electrode and the counter electrode serves as a working electrode.

[0053] In some specific embodiments, the metal conductor 9 is colinear with the central axis of the tubular metal cathode 8. In this way, a uniform self-generated electric field distribution can be formed around the metal conductor 9. According to the service condition of the test metal conductor 9, a constant voltage is set to be applied to the metal conductor 9, and a self-generated electric field that can simulate the working condition can be generated on the surface of the conductor 9. Exemplarily, the voltage that can be applied ranges from 0 to 1000V.

[0054] In some specific embodiments, the tubular metal negative electrode 8 is a copper negative electrode, or other conductive metals.

[0055] In some specific implementations, the metal conductor 9 is in the shape of a round rod.

[0056] In some specific embodiments, the thin liquid film system includes a sponge 3 soaked with a test solution, and the sponge 3 also covers the winding area of ​​the counter electrode and the reference electrode, and provides solution to the thin liquid film on the surface of the working electrode in the exposed area through capillary action with the porous film carrier of the thin liquid film medium 2.

[0057] In some specific embodiments, the thin liquid film medium 2 includes a porous film carrier and a solution adsorbed on the porous film carrier. Specifically, the porous film carrier can be a conventional porous film structure in the art, for example, it can be lens paper for wiping microscopes, or capacitor paper, etc. Such porous films have good hydrophilicity and stable chemical properties, and will not affect the electrode process.

[0058] In a more specific embodiment, the thickness of the thin liquid film medium 2 is 20-100 μm.

[0059] In some specific embodiments, the counter electrode is a platinum wire 4 , and the reference electrode is a silver wire covered with AgCl, that is, silver chloride / silver wire 5 .

[0060] In some specific embodiments, two counter electrodes are provided to maintain a more stable and uniform current distribution in the exposed area of ​​the working electrode.

[0061] The above embodiments may be implemented individually or in any combination of two or more.

[0062] The above implementation is described in detail below in conjunction with more specific examples.

[0063] Embodiment 1:

[0064] like Figure 1 As shown, this embodiment provides an electrochemical measurement device for simulating atmospheric corrosion of a metal conductor 9 under a self-generated electric field, which is used to study the atmospheric corrosion of the metal conductor 9 under a self-generated electric field. The measurement device includes:

[0065] The self-source electric field system comprises a grounded tubular metal negative electrode 8, which is a copper negative electrode and is fixed to a bracket by a fastening screw 15, and a constant voltage power supply whose positive and negative electrodes are respectively connected to the metal conductor 9 and the tubular metal negative electrode 8, wherein the positive electrode 10 of the constant voltage power supply is connected to the metal conductor 9; the negative electrode 14 of the constant voltage power supply is connected to the tubular metal negative electrode 8 and is grounded;

[0066] The support 16 is configured to fix and support a round rod-shaped metal conductor 9 and a tubular metal negative electrode 8 as a test sample, and allow the metal conductor 9 to pass through the tubular metal negative electrode 8 in parallel, and the metal conductor 9 is coated with an insulating film 1 except for the active area of ​​the working electrode;

[0067] The thin liquid film system comprises a thin liquid film medium 2 having an insulating film 1 and a working electrode region wound on the metal conductor 9, and a sponge 3 filled with a solution covering the winding region of the counter electrode and the reference electrode, and providing a thin liquid film environment for the thin liquid film through capillary action with a porous film carrier of the thin liquid film medium 2;

[0068] The three-electrode system includes a counter electrode (platinum wire 4) and a reference electrode (silver wire covered with AgCl, i.e., silver chloride / silver wire 5) respectively wound on the thin liquid film medium 2 of the metal conductor 9, and the exposed area 17 of the metal conductor 9 between the counter electrode and the reference electrode serves as the working electrode. For example, the exposed area is 1 cm 2 .

[0069] In addition, the metal conductor 9 is colinear with the central axis of the tubular metal cathode 8. In this way, a uniform electric field distribution can be formed around the metal conductor 9. According to the service condition of the test metal conductor 9, a constant voltage is set to be applied to the metal conductor 9, and a self-generated electric field simulating the service condition can be generated. Exemplarily, the voltage range that can be applied is 0 to 1000V.

[0070] In this embodiment, the thin liquid film medium 2 includes a porous film carrier and a solution adsorbed on the porous film carrier, specifically lens paper for wiping microscopes, and each layer of lens paper has a thickness of about 20 μm.

[0071] On the basis of the above, the construction of self-generated electric field was further studied. When the power transmission conductor is in service, the surface of the conductor has a surface electric field of up to 3000kV / m. In the device, a uniform self-generated electric field is generated on the surface of the conductor. It is necessary to introduce round rod-shaped conductor materials as electrodes, such as Figures 2 to 4 . Figure 2 It can be seen that for conductor metal rods of different diameters, the self-generated electric field strength on the conductor surface when different voltages are applied can be obtained through calculation, analysis and measurement. Under the same voltage, the self-generated electric field on the conductor surface increases as the diameter of the conductor rod decreases. Figure 3 It can be seen that the diameter of the tubular negative electrode has a great influence on the self-generated electric field on the conductor surface. As the diameter of the tubular negative electrode increases, the self-generated electric field on the conductor surface gradually decreases. Figure 4 When the diameter of the tubular negative electrode is 10cm, the relationship between the self-sourced electric field on the surface of the rod-shaped conductor and the diameter of the conductor is shown when a voltage of 2120V is applied to the rod-shaped conductor. It can be seen that under the condition of a certain applied voltage, the self-sourced electric field on the surface of the conductor increases as the radius of the conductor decreases. The above test results show that the device can obtain the self-sourced electric field under simulated working conditions by adjusting the applied voltage and the diameter of the rod-shaped conductor, meeting the needs of electrochemical measurement of atmospheric corrosion of conductors under self-sourced electric field conditions.

[0072] Based on the measurement device provided above, this embodiment also provides an electrochemical measurement method for atmospheric corrosion of a metal conductor 9 under a simulated self-generated electric field, which specifically includes the following steps:

[0073] (1) Collecting the service conditions of the energized metal conductor 9 (i.e., the object to be tested), including the service atmospheric environment, the level of pollutants, and the magnitude of the self-generated electric field strength on the surface of the metal conductor 9. And configuring the thin liquid film solution required for the simulation test according to the conductor service environment;

[0074] (2) A sample is prepared based on the metal conductor 9. In this embodiment, the sample is a cylindrical rod. Due to the voltage limit of the electrochemical workstation (<1000V), the diameter of the round rod needs to be determined according to the electromagnetic field strength of the working condition. The surface of the metal conductor 9 is ground, polished, and cleaned. After the active area of ​​the metal conductor 9 is left, the remaining area is coated with the insulating film 1 and dried. The metal conductor 9 is fixed horizontally on the bracket 16.

[0075] (3) A porous lens-cleaning paper 2 is wound around a metal conductor 9, a platinum wire 4 (as a counter electrode) and a silver wire 5 covered with AgCl (as a reference electrode) are wound around the porous lens-cleaning paper, and a sponge 3 is covered on the platinum wire 4 (as a counter electrode) and the silver wire 5 covered with AgCl (as a reference electrode);

[0076] (4) The leads of the platinum wire 4 (as the counter electrode) and the silver wire covered with AgCl (as the reference electrode) are led out through the counter electrode wire 6 and the reference electrode wire 7 and connected to the counter electrode terminal 12 and the reference electrode terminal 13 of the potentiostat respectively as the counter electrode and the reference electrode of the three-electrode system. The metal conductor 9 is also connected to the working electrode terminal 11 of the potentiostat through the leads and used as the working electrode of the three-electrode system. The atmospheric simulation solution is dripped onto the sponge, and the solution in the sponge is filled with the lens paper through the capillary action of the lens paper to form a thin liquid film medium. At the same time, the solution in the sponge can keep the solution in the lens paper in a saturated state to avoid changes in the state of the liquid film medium due to volatilization. Finally, the tubular metal shell of the self-sourced electric field system (i.e., the tubular metal negative electrode 8) is covered on the periphery of the three-electrode system. The metal conductor 9 is connected to the wiring of the positive electrode 10 of the constant voltage power supply, and the negative electrode 14 of the constant voltage power supply is connected to the metal shell of the self-sourced electric field system;

[0077] (5) After the experiment begins, according to the service conditions, the constant voltage power supply system is adjusted so that the voltage passes through the metal conductor 9, and the voltage range is 0 to 1000 V, so that a self-generated electric field that meets the working conditions is generated on the conductor surface;

[0078] (6) Turn on the potentiostat and measure the open circuit potential as needed. After stabilization, electrochemical measurements can be performed, including polarization curve and / or electrochemical impedance spectroscopy measurements;

[0079] (7) After the experiment, the constant current power supply system is turned off and the electrochemical data are analyzed to obtain the corrosion rate of the metal conductor 9 and the kinetic parameters of the corrosion process under the action of the self-source electric field.

[0080] Embodiment 2:

[0081] On the basis of Example 1, this embodiment selects pure aluminum (mass fraction> 99.99%) as a metal conductor to study the atmospheric corrosion characteristics of aluminum under the action of a self-source electric field; a reference electrode uses a silver wire covered with AgCl, and the preparation method of the silver wire of AgCl is as follows: first, the silver wire is placed in acetone for degreasing, then etched with 1 mol / L HNO3, then washed with distilled water and placed in 0.1 mol / L HCl, with the silver wire as the working electrode, calomel as the reference electrode, and a graphite plate as the counter electrode, and the parameter voltage is set to 0.1 V (relative to the open circuit potential) by the chronoamperometry, and the time is 2 h. After taking it out, it is compared with the saturated calomel electrode potential. The potential difference is about 35 mV, that is, the preparation is completed, and the prepared silver wire covered with AgCl is placed in a KCl solution and protected from light for use;

[0082] A group of pure aluminum samples were taken and mechanically processed into aluminum rods with a diameter of 2mm and a length of 50cm as the metal conductors of the experiment; before the test, each sample was polished step by step with 400#-2000# SiC sandpaper, cleaned with deionized water, then rinsed with alcohol to remove moisture, and dried with a hair dryer. The active area of ​​the dry metal surface used as the working electrode is wrapped with tape for shielding, and the remaining positions are sprayed with insulating paint and dried, and the shielding tape is removed to expose the exposed area as the working electrode area for standby use; the electrolyte solution in the simulated marine atmosphere is a 0.35% NaCl solution, which is prepared with analytical pure sodium chloride and deionized water; the voltage passing through the aluminum rod is controlled to be 0, 100, 200, 300, 400, 500, 600, and 700 V respectively, and the thickness of the thin liquid film is controlled to be 20μm, 40μm, 60μm, 80μm, and 100μm, respectively. The experimental device and experimental method of Example 1 are used to carry out electrochemical tests, mainly including open circuit potential test, polarization curve, and AC impedance test. After the test is completed, the electrochemical data are analyzed, and the specific results Figures 5 to 9 shown.

[0083] Figure 5 The polarization curves of pure aluminum at different voltages when the thin liquid film is 20 μm; Figure 6 The polarization curves of pure aluminum at different voltages when the thin liquid film is 20 μm ( Figure 5 ) to obtain the corrosion current density diagram. Figure 5 and Figure 6 It can be seen that when the thin liquid film is 20μm, the polarization curves and fitted corrosion current density diagrams of pure aluminum at different voltages show that as the voltage increases, the open circuit potential has a certain degree of negative shift, about 5-20mV range, and as the applied voltage increases, the corrosion current density of aluminum gradually increases. It can be seen that the atmospheric corrosion rate of aluminum increases with the increase of the surface self-source electric field.

[0084] In order to explore the effect of different electric field strengths on the corrosion behavior of metal aluminum under the same thin liquid film, electrochemical impedance spectroscopy was performed. Figure 7 The electrochemical impedance spectra of aluminum with different voltages applied when the thin film thickness is 20 μm are shown in Figure 1. Figure 8 The equivalent circuit is fitted, where R s is the solution resistance, R f is the film resistance of the aluminum surface oxide, Q is the constant phase angle element, and its physical meaning is the interface capacitance between the solution and the electrode, R ct is the charge transfer resistance in the electrochemical reaction process; Table 1 shows the Figure 8 Fitting parameters after fitting the equivalent circuit shown.

[0085] For the fitting parameters R in Table 1 ct Drawing, such as Fig. 9 ; Rct It reflects the inhibition of the charge transfer process and can also be used to evaluate the corrosion rate of metals. When voltage is applied to the metal, the charge transfer resistance R ct As the voltage increases, the corrosion rate of aluminum and R ct In other words, the atmospheric corrosion rate of aluminum increases with the increase of voltage (that is, the increase of the self-generated electric field on the surface), and compared with the case without power supply, R ct The large reduction indicates that the atmospheric corrosion rate of metal aluminum is related to the magnitude of the self-generated electric field, and the self-generated electric field does have an impact on the corrosion of metal aluminum.

[0086] Table 1 Fitting parameters of electrochemical impedance spectroscopy of atmospheric corrosion of aluminum under self-generated electric field

[0087] Energizing voltage / V <![CDATA[R s ]]> n <![CDATA[R f ]]> <![CDATA[R ct ]]> 0 0.3818 0.8144 264.4 8261 100 0.4063 0.8094 342.3 6024 200 0.5144 0.8557 336.8 4704 300 0.4081 0.9125 277.3 4086 400 0.8236 0.9362 524.5 2366 500 0.4737 0.8359 224.3 2353 600 0.8574 0.9679 500.2 1865 700 1.33 0.8389 313.8 1723

[0088] In summary, it has been verified that the results of the thin liquid film device for atmospheric corrosion of metals under the action of a self-source electric field simulated by this embodiment are relatively accurate and closer to the actual working conditions, and can more accurately simulate the atmospheric corrosion of power grid transmission conductors.

[0089] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. An electrochemical measurement device for atmospheric corrosion of metal conductors under simulated self-generated electric fields, used to study the atmospheric corrosion of metal conductors under self-generated electric field conditions generated by power supply, characterized in that: The measuring device comprises: A self-generated electric field system comprises a grounded tubular metal cathode and a constant voltage power source whose positive and negative electrodes are respectively connected to the metal conductor and the tubular metal cathode; A bracket, configured to fixedly support a metal conductor and a tubular metal negative electrode as a test sample, and to allow the metal conductor to pass through the tubular metal negative electrode in parallel, and the metal conductor is also coated with an insulating film; A thin liquid film system, comprising a thin liquid film medium having an insulating film region and a working electrode region wound on the metal conductor, the thin liquid film medium being used to provide a target test solution environment for the metal conductor; The three-electrode system comprises a counter electrode and a reference electrode respectively wound on the thin liquid film medium of the metal conductor, and the exposed area of ​​the metal conductor serves as a working electrode.

2. The electrochemical measuring device for atmospheric corrosion of metal conductors under simulated self-generated electric fields according to claim 1, characterized in that: The metal conductor is colinear with the central axis of the tubular metal negative electrode.

3. The electrochemical measurement device for atmospheric corrosion of metal conductors under simulated self-generated electric fields according to claim 1, characterized in that: The tubular metal negative electrode is a copper negative electrode.

4. The electrochemical measurement device for atmospheric corrosion of metal conductors under simulated self-generated electric fields according to claim 1, characterized in that: The metal conductor is in the shape of a round rod.

5. The electrochemical measurement device for atmospheric corrosion of metal conductors under simulated self-generated electric fields according to claim 1, characterized in that: The thin liquid film system includes a sponge filled with a test solution as a liquid supply source of the test solution, and the sponge also covers the winding area of ​​the counter electrode and the reference electrode.

6. The electrochemical measurement device for atmospheric corrosion of metal conductors under simulated self-generated electric fields according to claim 1, characterized in that: The thin liquid film medium comprises a porous film carrier and a solution adsorbed on the porous film carrier.

7. The electrochemical measurement device for atmospheric corrosion of metal conductors under simulated self-generated electric fields according to claim 6, characterized in that: The thickness of the thin liquid film medium is 20-100 μm.

8. The electrochemical measurement device for atmospheric corrosion of metal conductors under simulated self-generated electric fields according to claim 1, characterized in that: The counter electrode is a platinum wire, and the reference electrode is a silver wire covered with AgCl.

9. The electrochemical measurement device for atmospheric corrosion of metal conductors under simulated self-generated electric fields according to claim 1, characterized in that: There are two counter electrodes.

10. An electrochemical measurement method for atmospheric corrosion of a metal conductor under a simulated self-generated electric field, which is implemented based on the measurement device according to any one of claims 1 to 9, characterized in that: The measuring method comprises the following steps: (1) Collecting environmental characteristic parameters of the service conditions of the metal conductor and preparing a test solution simulating the service conditions; (2) preparing a test sample based on a metal conductor, grinding, polishing and cleaning the surface of the test sample, coating an insulating film on the winding position of the reference electrode and the counter electrode and drying it, leaving an exposed area between the reference electrode and the counter electrode as the working electrode, and fixing the test sample horizontally on a bracket; (3) winding a porous film carrier around the reference electrode and the counter electrode of the test sample and the exposed working electrode; (4) Wrapping the reference electrode and the counter electrode on the porous film carrier of the corresponding area, and then covering and assembling the reference electrode and the counter electrode with two sponges, after completion, dripping the test solution onto the sponge so that the sponge is filled with the test solution, and the porous film carrier is also filled with the test solution through the sponge to form a thin liquid film medium, and then, the reference electrode and the counter electrode are respectively led out through wires and connected to the counter electrode end and the reference electrode end of the constant potential instrument, and the test sample is also led out through wires and connected to the working electrode end of the constant potential instrument to form a three-electrode system; (5) Covering the tubular metal negative electrode of the self-source electric field system around the test sample and the three-electrode system, and fixing the tubular metal negative electrode by a bracket, connecting the test sample to the positive electrode of the constant voltage power supply, and connecting the tubular metal negative electrode to the negative electrode of the constant voltage power supply; (6) After the test begins, adjust the voltage of the constant voltage power supply according to the service conditions to obtain the required self-generated electric field; (7) Turn on the potentiostat, measure the open circuit potential as needed, perform electrochemical measurement after stabilization, and analyze the electrochemical data to obtain the corrosion rate of the metal conductor under the action of the self-source electric field and the kinetic parameters of the corrosion process.

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