Electrochemical measurement device and method for simulating atmospheric corrosion of a metal conductor under a self-generated electric field

Abstract

The present application relates to a device and method for atmospheric corrosion electrochemical measurement of a metal conductor under simulated self-generated electric field, the measurement device comprising: a self-generated electric field system comprising a grounded tubular metal negative electrode and a constant voltage power supply connected to the metal conductor and the tubular metal negative electrode respectively; a support configured to fixedly support the metal conductor as a test sample and the tubular metal negative electrode, the metal conductor being coated with an insulating film except for a working electrode exposed area; a thin liquid film system comprising a thin liquid film medium wound around the area of the metal conductor with the insulating film and the working electrode exposed area, the thin liquid film medium being used to provide a target test solution environment for the metal conductor; a three-electrode system comprising a counter electrode and a reference electrode, the metal conductor exposed area serving as a working electrode. The present application can perform atmospheric corrosion thin liquid film electrochemical measurement of a metal conductor under different atmospheric environment level parameters under various different self-generated electric field service conditions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrochemical corrosion test, and relates to an atmospheric corrosion electrochemical measurement device and method for simulating a metal conductor under a self-source electric field. BACKGROUND

[0002] The environment to which a power grid transmission conductor is subjected during service is relatively complex. In addition to being affected by temperature, air humidity in the atmosphere, and pollutants in the air, the conductor is also affected by a self-source electric field generated by the transmission conductor. Preliminary analysis and screening by power inspection personnel have found that the corrosion of the transmission line in service is quite different from that in a conventional atmospheric corrosion environment in terms of both the morphology of the corrosion products and the corrosion rate. Related research has shown that the self-source electric field generated by the conductor during service can accelerate the corrosion of the metal. However, most of the research focuses on the atmospheric corrosion of the metal under an external electric field, i.e., the corrosion of the metal under the action of an external electric field. Therefore, further research on the atmospheric corrosion mechanism and test method of the metal under the action of a self-source electric field is of great significance to the safe operation of the power grid transmission conductor in service.

[0003] In a power transmission and transformation system, a self-source electric field is generated on the surface of a metal conductor, which has a great influence on the corrosion of the metal. Salt spray test and electrochemical measurement methods are commonly used in atmospheric corrosion tests. Electrochemical measurement has the advantages of being fast and effective, and not only can the corrosion rate of the metal material in the atmosphere be obtained, but the dynamic mechanism of the atmospheric corrosion process of the metal can also be studied in depth. Thin liquid film devices are commonly used in atmospheric corrosion electrochemical measurement to measure the initial corrosion process dynamics of the metal in the atmospheric environment by generating a certain thickness of electrolyte liquid film on the surface of the metal electrode and establishing a three-electrode system.

[0004] Chinese Patent Application CN117686416A discloses an atmospheric corrosion thin liquid film experimental device and experimental method for a live metal conductor, which realizes corrosion electrochemical measurement of the conductor under a self-source magnetic field generated by a live working condition 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 problems of establishing a thin liquid film system and a uniform self-source magnetic field on the surface of a round rod electrode, but still cannot meet the research on the atmospheric corrosion of the metal under a self-source electric field generated by the service working condition of the power grid conductor. SUMMARY

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

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

[0007] Applicant found through research that the traditional thin liquid film electrochemical measurement device cannot meet the metal atmospheric corrosion research under the self-source electric field generated by the service working condition of power grid conductor, the main reasons are:

[0008] 1. In the service working condition of power grid transmission conductor, there is a surface self-source electric field of up to 3000kV / m on the surface of the conductor, a high and uniform self-source electric field needs to be generated on the surface of the conductor in the simulation device, therefore, a round rod conductor material needs to be introduced as an electrode, and the existing device lacks relevant supporting design for providing a uniform self-source electric field;

[0009] 2. Due to the introduction of the peripheral negative electrode, the space around the electrode is small, and the conventional thin liquid film thickness control system and liquid film thickness maintaining 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 small, and the conventional three-electrode system and the connection mode with the electrochemical workstation will affect the spatial distribution of the self-source electric field, and cannot meet the requirements of the thin liquid film system under the self-source electric field.

[0011] Based on this, the application provides an atmospheric corrosion electrochemical measurement device for simulating the metal conductor under the self-source electric field, which is used for researching the atmospheric corrosion of the metal conductor under the self-source electric field condition, and the measurement device comprises:

[0012] a self-source electric field system, comprising a tubular metal negative electrode grounded and a constant voltage power supply connecting the metal conductor and the tubular metal negative electrode as the positive and negative electrodes;

[0013] a support configured to fixedly support the metal conductor as a test sample and the tubular metal negative electrode, and make the metal conductor pass through the tubular metal negative electrode in parallel, and the metal conductor is also partially coated with an insulating film for avoiding the electric contact between the counter electrode, the reference electrode and the metal conductor;

[0014] a thin liquid film system, comprising a thin liquid film medium wound on the area with the insulating film and the working electrode area of the metal conductor, the medium is composed of a porous film carrier and an electrolyte, and the thin liquid film medium is used for providing a target test thin liquid film environment for the metal conductor;

[0015] a three-electrode system, comprising a counter electrode and a reference electrode wound on the thin liquid film medium of the metal conductor, and an exposed area of the metal conductor without coating the insulating film as a working electrode in the area between the counter electrode and the reference electrode.

[0016] Further, the central axes of the metal conductor and the tubular metal negative electrode are collinear.

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

[0018] Further, the metal conductor is in the shape of a round bar.

[0019] Further, the thin liquid film system further comprises sponges soaked with the test solution, which are wrapped around the reference electrode and the counter electrode and connected to the porous film carrier, for providing the test solution to the porous film carrier and avoiding the change of the thickness of the thin liquid film caused by the evaporation of the electrolyte in the film carrier.

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

[0021] Further, 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] Further, the counter electrode is a platinum wire and the reference electrode is a silver wire covered with AgCl.

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

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

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

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

[0027] (3) Wrapping the porous film carrier at the wrapping position of the reference electrode and the counter electrode of the test sample and the exposed working electrode;

[0028] (4) Wrapping the reference electrode and the counter electrode on the porous film carrier in the corresponding area, and wrapping two sponges around the reference electrode and the counter electrode. After completion, add test solution droplets to the sponges to make the sponges full of test solution, and make the porous film carrier also full of test solution to form a thin liquid film medium. Then, the reference electrode and the counter electrode are led out through wires and connected to the counter electrode end and the reference electrode end of the potentiostat, and 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) the tubular metal negative electrode shield of the self-originating electric field system is arranged outside the test sample and the three-electrode system, and the tubular metal negative electrode is fixed by a support, the test sample is connected with the positive electrode of the constant-voltage power supply, and the tubular metal negative electrode is connected with the negative electrode of the constant-voltage power supply;

[0030] (6) after the test starts, the voltage of the constant-voltage power supply is adjusted according to the service condition to obtain the required self-originating electric field;

[0031] (7) the constant potential instrument is started, the open circuit potential is measured according to the requirement, the electrochemical measurement is carried out after stabilization, and the corrosion speed and the corrosion process kinetic parameter of the metal conductor under the action of the self-originating electric field are obtained by analyzing the electrochemical data.

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

[0033] (1) the self-originating electric field condition and the thin liquid film condition of the conductor service condition are constructed for the thin liquid film experimental technology requirement of the atmospheric corrosion of the conductor metal under the self-originating electric field;

[0034] (2) the atmospheric corrosion thin liquid film electrochemical measurement of the powered conductor metal under various self-originating electric field service environments and at various self-originating electric field parameter levels can be carried out. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 it is a structural schematic view of the measuring device of the present application;

[0036] Figure 2 it is a graph of the change rule of the electric field intensity of the surface of the conductor rod with the input voltage at different diameters;

[0037] Figure 3 it is a graph of the change rule of the electric field intensity of the different diameter conductors with the different shell diameters under the voltage of 1000V;

[0038] Figure 4 it is a change trend of the electric field intensity with the conductor rod diameter under the voltage of 2120V under the tubular grounding shell with the diameter of 10cm;

[0039] Figure 5 it is a polarization curve of pure aluminum under different voltages when the thin liquid film is 20μm;

[0040] Figure 6 it is a corrosion current density graph of pure aluminum under different voltages when the thin liquid film is 20μm;

[0041] Figure 7 it is an impedance spectrum graph of aluminum under different voltages when the thin liquid film thickness is 20μm;

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

[0043] Figure 9 Fitting parameters R for aluminum under applied voltage conditions for thin liquid film of 20 μm ct correlation;

[0044] Legend of the figures:

[0045] 1 - Insulating film; 2 - Thin liquid film medium; 3 - Sponge; 4 - Platinum wire; 5 - Silver chloride / silver wire; 6 - Counter electrode lead; 7 - Reference electrode lead; 8 - Tubular metal negative electrode; 9 - Metal conductor; 10 - Constant voltage power supply positive pole; 11 - Working electrode end; 12 - Counter electrode end; 13 - Reference electrode end; 14 - Constant voltage power supply negative pole; 15 - Fastening screw; 16 - Holder; 17 - Conductor working electrode exposed area. DETAILED DESCRIPTION

[0046] The application will be described in greater detail below with reference to the drawings and specific embodiments. The embodiments are implemented on the premise of the technical solution of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following embodiments.

[0047] In the following embodiments or examples, if no specific description is given for the function components or structures, it is indicated that they are all conventional components or conventional structures adopted in the field to realize the corresponding functions.

[0048] In order to carry out atmospheric corrosion thin liquid film electrochemical measurement of the conductor metal under the service of self-generated electric field at different environmental level parameters, the application provides an atmospheric corrosion electrochemical measurement device for simulating a metal conductor 9 under a self-generated electric field, for studying the atmospheric corrosion of the metal conductor 9 under the self-generated electric field working condition, and the measurement device comprises:

[0049] A self-generated electric field system comprises a tubular metal negative electrode 8 grounded, and a constant voltage power supply with the metal conductor 9 and the tubular metal negative electrode 8 connected as the positive and negative electrodes respectively;

[0050] A holder 16 is configured to fixedly support the metal conductor 9 as a test sample and the tubular metal negative electrode 8, and to make the metal conductor 9 pass through the tubular metal negative electrode 8 in parallel, and the metal conductor 9 is further coated with an insulating film 1;

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

[0052] A three-electrode system, including a counter electrode 4 and a reference electrode 5, which are respectively wound on the thin liquid film medium 2 at two insulating regions of the metal conductor 9, and an exposed region 17 between the reference electrode and the counter electrode as the working electrode, without insulating film coating on the metal conductor 9.

[0053] In some specific embodiments, the metal conductor 9 is collinear with the central axis of the tubular metal negative electrode 8. In this way, a uniform self-sourced electric field distribution can be formed around the metal conductor 9, and a self-sourced electric field that can simulate the working condition can be generated on the surface of the conductor 9 by setting a constant voltage applied to the metal conductor 9 according to the service working condition of the test metal conductor 9. For example, the applied voltage can range from 0 to 1000V.

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

[0055] In some specific embodiments, the metal conductor 9 is in the form of a round bar.

[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 region of the counter electrode and the reference electrode, and provides the solution for the thin liquid film on the surface of the working electrode of the exposed region 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 porous film structure that can be conventional in the art, for example, a lens cleaning paper for microscopes or a condenser paper, etc. Such porous films have good hydrophilicity and stable chemical properties, and will not affect the electrode process.

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

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

[0060] In some specific embodiments, the counter electrode is provided with two, which can maintain a more stable and uniform current distribution on the exposed region of the working electrode.

[0061] Any of the above embodiments can be implemented individually, or any two or more can be combined.

[0062] The above embodiments will be described in detail below in conjunction with more specific examples.

[0063] Example 1:

[0064] As Figure 1 shown in the figure, the embodiment provides an atmospheric corrosion electrochemical measuring device for simulating the metal conductor 9 under the self-induced electric field, which is used to study the atmospheric corrosion of the metal conductor 9 under the self-induced electric field, and the measuring device comprises:

[0065] a self-induced electric field system, which comprises a grounded tubular metal negative electrode 8, the tubular metal negative electrode 8 is a copper negative electrode, and is fixed on a support through a fastening screw 15, and a constant voltage power supply respectively connecting the metal conductor 9 and the tubular metal negative electrode 8, wherein the positive electrode 10 of the constant voltage power supply is connected with the metal conductor 9; the negative electrode 14 of the constant voltage power supply is connected with the tubular metal negative electrode 8 and grounded;

[0066] a support 16, which is configured to fix and support the metal conductor 9 in the form of a round bar as a test sample and the tubular metal negative electrode 8, and make the metal conductor 9 pass through the tubular metal negative electrode 8 in parallel, and the rest of the metal conductor 9 except the working electrode active area is coated with an insulating film 1;

[0067] a thin liquid film system, which comprises a thin liquid film medium 2 wound on the area of the metal conductor 9 with the insulating film 1 and the working electrode area, and a solution-absorbed sponge 3 covering the counter electrode and reference electrode winding area, and provides a thin liquid film environment for the thin liquid film through the capillary action of the porous film carrier of the thin liquid film medium 2;

[0068] a three-electrode system, which comprises a counter electrode (platinum wire 4) and a reference electrode (silver wire covered with AgCl, i.e. silver chloride / silver wire 5) 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 as a working electrode. Exemplarily, the exposed area is 1 cm 2 .

[0069] In addition, the central axes of the metal conductor 9 and the tubular metal negative electrode 8 are collinear. In this way, a uniform electric field distribution can be formed around the metal conductor 9, and according to the service condition of the test metal conductor 9, a constant voltage is applied to the metal conductor 9 to generate a self-induced electric field simulating the working condition. Exemplarily, the applicable voltage range is 0-1000V.

[0070] In the embodiment, the thin liquid film medium 2 comprises a porous film carrier and a solution adsorbed on the porous film carrier, specifically a lens cleaning paper such as a microscope, and the thickness of each layer of the lens cleaning paper is about 20μm.

[0071] On the basis of the above, the construction of the self-originating electric field is further studied. In the service condition of the power grid transmission conductor, the surface electric field of the conductor is as high as 3000 kV / m. The device generates a uniform self-originating electric field on the surface of the conductor. A round rod conductor material needs to be introduced as an electrode, such as Figures 2 to 4 . Figure 2 It can be seen that, for conductors of different diameters, the self-originating electric field intensity on the surface of the conductor under different voltages is obtained through calculation analysis and measurement. Under the same voltage, the self-originating electric field on the surface of the conductor increases with the decrease of the diameter of the conductor rod. Figure 3 It can be seen that the diameter of the tubular negative electrode has a great influence on the self-originating electric field on the surface of the conductor. With the increase of the diameter of the tubular negative electrode, the self-originating electric field on the surface of the conductor gradually decreases. Figure 4 For the tubular negative electrode with a diameter of 10 cm, the relationship between the self-originating electric field on the surface of the rod-shaped conductor and the diameter of the conductor under the voltage of 2120 V applied to the rod-shaped conductor can be seen. Under the condition of a certain applied voltage, the self-originating electric field on the surface of the conductor increases with the decrease of the radius of the conductor. The above test results show that the device can obtain the self-originating electric field under the simulated working condition by adjusting the applied voltage and the diameter of the rod-shaped conductor, which meets the needs of the electrochemical measurement of the atmospheric corrosion of the conductor under the self-originating electric field working condition.

[0072] On the basis of the above-provided measuring device, the embodiment also provides an atmospheric corrosion electrochemical measurement method for simulating the self-originating electric field of the metal conductor 9, which specifically includes the following steps:

[0073] (1) Collect the service working condition of the electrified metal conductor 9 (i.e. the measured object), including the service atmospheric environment, the pollutant level and the self-originating electric field intensity on the surface of the metal conductor 9. And according to the service environment of the conductor, configure the thin liquid film solution required for the simulation test;

[0074] (2) Based on the metal conductor 9, a sample is made. In this embodiment, the sample is a cylindrical rod, which is limited by the withstand voltage of the electrochemical workstation (<1000 V). The diameter of the circular rod needs to be determined according to the intensity of the working electromagnetic field. The surface of the metal conductor 9 is polished, polished and cleaned. After the active area of the metal conductor 9 is left, the remaining area is coated with an insulating film 1 and dried. The metal conductor 9 is fixed horizontally on the support 16;

[0075] (3) Wrap the porous lens cleaning paper 2 on the metal conductor 9. Wrap the platinum wire 4 (as the counter electrode) and the silver wire 5 covered with AgCl (as the reference electrode) on the porous lens cleaning paper. Cover the platinum wire 4 (as the counter electrode) and the silver wire covered with AgCl (as the reference electrode) with the sponge 3;

[0076] (4) The lead wires of the platinum wire 4 (as the counter electrode) and the silver wire covered with AgCl (as the reference electrode) are respectively led out through the counter electrode lead 6 and the reference electrode lead 7 and connected to the counter electrode end 12 and the reference electrode end 13 of the constant potential instrument to serve as the counter electrode and the reference electrode of the three-electrode system. The metal conductor 9 is also connected to the working electrode end 11 of the constant potential instrument through a lead wire to serve as the working electrode of the three-electrode system. The atmospheric simulation solution is added dropwise to the sponge, and the solution in the sponge is saturated by the capillary action of the lens paper to make the lens paper full of the solution to form a thin liquid film medium. At the same time, the solution in the sponge can keep the solution in the lens paper saturated, avoiding changes in the state of the liquid film medium due to volatilization. Finally, the tubular metal shell (i.e., the tubular metal negative electrode 8) of the self-sourced electric field system is covered around the three-electrode system. The metal conductor 9 is connected to the positive pole 10 of the constant voltage power supply, and the negative pole 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 starts, the constant voltage power supply system is adjusted according to the service conditions to make the voltage pass through the metal conductor 9, and the voltage range is 0-1000V, so that the self-sourced electric field on the surface of the conductor is generated to meet the working conditions;

[0078] (6) The constant potential instrument is turned on, and the open circuit potential is measured as needed. After stabilization, electrochemical measurement can be carried out, including polarization curve and / or electrochemical impedance spectrum measurement;

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

[0080] Example 2:

[0081] On the basis of Example 1, pure aluminum (mass fraction > 99.99%) is selected as the metal conductor in this example to study the atmospheric corrosion characteristics of aluminum under the action of the self-sourced electric field. The reference electrode uses a silver wire covered with AgCl. The preparation method of the silver wire covered with AgCl is as follows: first, the silver wire is placed in acetone to remove oil, then immersed in 1 mol / L HNO3 for etching, and then washed with distilled water and placed in 0.1 mol / L HCl. The silver wire is used as the working electrode, the mercury amalgam is used as the reference electrode, and the graphite plate is used as the counter electrode. The parameter voltage is set to 0.1V (relative to the open circuit potential) by chronocoulometry, the time is 2h, and the potential difference is compared with the saturated mercury electrode potential after taking out. The potential difference is about 35mV, which means that the preparation is completed. The prepared silver wire covered with AgCl is stored in KCl solution in the dark for use;

[0082] A set of pure aluminum samples were machined into aluminum rods with a diameter of 2 mm and a length of 50 cm to serve as the metal conductors for the experiment. Before the experiment, each sample was polished step by step with SiC sandpaper of 400#-2000#, cleaned with deionized water, rinsed with alcohol to remove moisture, and dried with a hair dryer. The active area of ​​the working electrode on a dry metal surface was shielded with tape, and the remaining areas were sprayed with insulating varnish and dried. The shielding tape was then removed to expose the exposed area, which was then used as the working electrode area. The electrolyte solution simulating a marine atmosphere was a 0.35% NaCl solution prepared with analytical grade sodium chloride and deionized water. Voltages through the aluminum rod were controlled at 0, 100, 200, 300, 400, 500, 600, and 700 V, and the thickness of the thin liquid film was controlled at 20 μm, 40 μm, 60 μm, 80 μm, and 100 μm. Electrochemical tests were performed using the experimental setup and methods of Example 1, including open-circuit potential testing, polarization curve analysis, and AC impedance testing. After the experiment, the electrochemical data were analyzed, and the specific results were... Figures 5 to 9 As shown.

[0083] Figure 5 The polarization curves of pure aluminum under different voltages are shown for a thin liquid film of 20 μm. Figure 6 The polarization curves of pure aluminum under different voltages when the thin liquid film is 20 μm. Figure 5 The corrosion current density map was obtained through analysis. Combined with... Figure 5 and Figure 6 It can be seen from the polarization curves and fitted corrosion current density diagrams of pure aluminum at different voltages when the thin liquid film is 20 μm. As the voltage increases, the open-circuit potential shifts negatively to a certain extent, approximately in the range of 5–20 mV. Furthermore, the corrosion current density of aluminum gradually increases with increasing applied voltage. This indicates that the atmospheric corrosion rate of aluminum increases with the increase of the surface-generated electric field.

[0084] To investigate the effect of different electric field strengths on the corrosion behavior of metallic aluminum under the same thin liquid film, electrochemical impedance spectroscopy measurements were performed. Figure 7 Electrochemical impedance spectroscopy (EIS) spectra of aluminum with different applied voltages when the thin liquid film thickness is 20 μm is obtained. Based on the characteristic EIS spectra of aluminum, the following methods were used: Figure 8 The equivalent circuit is fitted, where R s R is the resistance of the solution. f R is the film resistance of the aluminum surface oxide, Q is a constant phase angle element, and its physical meaning is the interfacial capacitance between the solution and the electrode. ct This refers to the charge transfer resistance during the electrochemical reaction process; Table 1 shows the resistance achieved using... Figure 8 The fitting parameters of the equivalent circuit shown are obtained after fitting.

[0085] For the fitting parameters R in Table 1 ct Drawing, such as Figure 9 ;Rct Reflects the inhibition of charge transfer process, also can be used to assess the corrosion rate of metal; when the voltage is applied to the metal, the charge transfer resistance R ct Decreases with the increase of voltage, the corrosion rate of aluminum metal and R ct Are inversely proportional, that is, the atmospheric corrosion rate of aluminum metal gradually increases with the increase of voltage (that is, the increase of surface self-source electric field), and compared with no power, R ct Decreases greatly, indicating that the atmospheric corrosion rate of aluminum metal is related to the size of self-source electric field, and the self-source electric field indeed has an impact on the corrosion of aluminum metal.

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

[0087] Energizing voltage / V [R s ]]> n [R f ]] [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 atmospheric corrosion thin liquid film device of metal under the action of self-source electric field simulated by the embodiment is more accurate, and the results are more close to the actual working conditions, which can more accurately simulate the atmospheric corrosion of power transmission conductor.

[0089] The above description of the embodiments is for the convenience of the ordinary skilled in the art to understand and use the invention. Those skilled in the art can obviously make various modifications to these embodiments, and apply the general principles described herein to other embodiments without the need for creative labor. Therefore, the present application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art according to the disclosure of the present application without departing from the scope of the present application should be within the scope of protection of the present application.

Claims

1. An atmospheric corrosion electrochemical measuring device for simulating a metal conductor under a self-induced electric field, for studying atmospheric corrosion of a metal conductor under a self-induced electric field generated by electrification, characterized in that, The measuring device comprises: A self-sourced electric field system comprising a grounded tubular metal negative electrode and a constant voltage power supply connecting the metal conductor and the tubular metal negative electrode respectively; A support configured to fix and support the metal conductor as a test sample and the tubular metal negative electrode, and to make the metal conductor pass through the tubular metal negative electrode in parallel, the metal conductor being further coated with an insulating film; A thin liquid film system comprising a thin liquid film medium wound on the area of the metal conductor with the insulating film and the working electrode area, the thin liquid film medium being used to provide a target test solution environment for the metal conductor; A three-electrode system comprising a counter electrode and a reference electrode wound on the thin liquid film medium of the metal conductor respectively, and the exposed area of the metal conductor as a working electrode; The central axis of the metal conductor is collinear with that of the tubular metal negative electrode; The tubular metal negative electrode is a copper negative electrode; The metal conductor is in the form of a round bar; The thin liquid film system comprises a sponge soaked with a test solution as a liquid supply source of the test solution, the sponge also covering the counter electrode and reference electrode winding area; The thin liquid film medium comprises a porous film carrier and a solution adsorbed on the porous film carrier.

2. An apparatus for electrochemical measurement of atmospheric corrosion of a metal conductor under simulated self-generated electric field as claimed in claim 1, wherein The thickness of the thin liquid film medium is 20-100 μm.

3. An apparatus for electrochemical measurement of atmospheric corrosion of a metal conductor under simulated self-generated electric field as claimed in claim 1, wherein The counter electrode is a platinum wire, and the reference electrode is a silver wire covered with AgCl.

4. An apparatus for electrochemical measurement of atmospheric corrosion of a metal conductor under simulated self-generated electric field as claimed in claim 1, wherein The counter electrode is provided with two.

5. A method for electrochemical measurement of atmospheric corrosion of a metal conductor under a simulated self-generated electric field, based on the measurement device according to any one of claims 1 to 4, characterized in that, The measuring method comprises the following steps: (1) Collecting the environmental characteristic parameters of the service working condition of the metal conductor, and preparing a test solution simulating the working condition; (2) Preparing a test sample based on the metal conductor, polishing, polishing and cleaning the surface of the test sample, coating an insulating film at the reference electrode and counter electrode winding positions and drying, leaving an exposed area between the reference electrode and the counter electrode as a working electrode, and fixing the test sample horizontally on the support; (3) Winding a porous film carrier at the reference electrode and counter electrode winding positions and the exposed working electrode of the test sample; (4) Winding the reference electrode and counter electrode on the corresponding area of the porous film carrier, covering the reference electrode and counter electrode with two sponges, adding test solution droplets to the sponges to make the sponges full of test solution, and making the porous film carrier also full of test solution to form a thin liquid film medium, then leading out the reference electrode and counter electrode through wires and connecting them with the counter electrode end and reference electrode end of a constant potential instrument, and leading out the test sample through a wire and connecting it with the working electrode end of the constant potential instrument to form a three-electrode system; (5) Covering the test sample and the three-electrode system with the tubular metal negative electrode of the self-sourced electric field system, fixing the tubular metal negative electrode through the support, connecting the test sample with the positive electrode of the constant voltage power supply, and connecting the tubular metal negative electrode with the negative electrode of the constant voltage power supply; (6) After starting the test, adjusting the voltage of the constant voltage power supply according to the service working condition to obtain the required self-sourced electric field; (7) Starting the constant potential instrument, measuring the open circuit potential as required, performing electrochemical measurement after stabilization, and analyzing the electrochemical data to obtain the corrosion rate and corrosion process kinetic parameters of the metal conductor under the action of the self-sourced electric field.

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