Micro-area working electrode for measuring failure of cement mortar lining and use method of micro-area working electrode

Abstract

The invention provides a micro-area working electrode for measuring cement mortar lining failure and a use method thereof, the micro-area working electrode comprises a cement mortar lining and nodular cast iron electrodes symmetrically arranged below the cement mortar lining, and a corrosive medium is arranged between the cement mortar lining and the nodular cast iron electrodes; a first insulating layer is arranged on the periphery of the cement mortar lining, a second insulating layer is arranged on the periphery of the nodular cast iron electrode, and the second insulating layer and the first insulating layer are fixedly connected through connecting screws. The electrode can simulate the state of the inner surface of a nodular cast iron pipeline with a cement mortar lining in the whole life cycle, and the problem that existing water supply pipeline corrosion research cannot comprehensively simulate the protection effect of the cement mortar lining in each life cycle is solved. The problem that electrochemical detection cannot be carried out on the corroded nodular cast iron pipe wall is solved, research on the corrosion process and the corrosion mechanism of long-term service of the water supply pipeline becomes possible, and the method has important significance on service life evaluation and corrosion protection of an urban water supply pipe network.

Description

Technical Field

[0001] The present invention relates to the technical field of drinking water supply pipe network detection. Specifically, it relates to a micro-area working electrode for measuring the failure of cement mortar lining and its usage method. Background Art

[0002] The safety of drinking water supply is crucial for ensuring public health and the normal operation of cities. Currently, cement mortar lining is generally used on the inner wall of metal pipes in drinking water supply pipe networks to prevent pipe corrosion and ensure water quality. However, after long-term operation of the pipe network, the cement mortar lining may experience failure phenomena such as aging, cracking, and even partial peeling, resulting in a decline in the protective effect of the lining on the pipe, thus affecting the water supply quality and shortening the service life of the pipe.

[0003] Existing electrochemical detection methods usually use a single metal electrode for average measurement over a relatively large area, obtaining regional average corrosion data, which cannot accurately reflect the true corrosion conditions of local areas (such as defect points and weak areas) of the cement mortar lining, and thus easily overlook local early corrosion signals. As the operation years of the water supply pipe increase, the lining material may undergo microstructural changes due to long-term physicochemical interactions with water quality, such as the gradual formation and expansion of micropores and cracks. These microstructural changes further promote the local corrosion of the pipe matrix metal. However, existing electrochemical technical means are difficult to capture the change characteristics of these early micro-area electrochemical behaviors, thus reducing the early warning ability for pipe failure.

[0004] In view of the above situation, existing electrochemical detection technologies have obvious deficiencies in spatial resolution, sensitivity, and real-time monitoring ability, and are difficult to capture the electrochemical signals of early local failure of the cement mortar lining in a timely and accurate manner. Therefore, there is an urgent need to develop a new technology or device that can realize real-time monitoring of the electrochemical characteristics of the cement mortar lining at the micro-area scale, so as to improve the detection accuracy of the lining failure of the pipe network and the early warning ability of pipe corrosion, and ensure the long-term safe operation of the urban water supply pipe network. Summary of the Invention

[0005] In view of this, the present invention proposes a micro - area working electrode for measuring the failure of cement mortar lining and its use method, which is used to directly measure local electrochemical parameters on the surface of the cement mortar lining, so as to monitor the failure process of the lining. This micro - area working electrode is small in volume and high in resolution, and can be close to a specific position of the cement mortar lining for in - situ electrochemical measurement. Its design takes into account the actual environment of the water supply pipe network, enabling the electrode to accurately obtain electrochemical data such as potential and current density in a local area, and complete the measurement without damaging the lining structure. By using this electrode, processes such as microscopic corrosion reactions and passivation film rupture on the lining surface can be monitored and recorded in real time. When early failure signs (such as local pH changes and increased corrosion current) appear in the cement mortar lining, the electrode will capture these local electrochemical signals. Compared with traditional macroscopic electrochemical tests, the micro - area working electrode of the present invention can more sensitively reflect the state changes in the fine areas of the lining.

[0006] On the one hand, to achieve the above - mentioned purpose, the present invention proposes a micro - area working electrode for measuring the failure of cement mortar lining, which is characterized in that it includes a cement mortar lining, a ductile iron electrode is provided below the cement mortar lining, and a corrosive medium is provided between the cement mortar lining and the ductile iron electrode;

[0007] A first insulating layer is arranged on the periphery of the cement mortar lining, a second insulating layer is arranged on the periphery of the ductile iron electrode, and the second insulating layer and the first insulating layer are fixedly connected by connecting screws.

[0008] Furthermore, mounting holes are provided on the first insulating layer; threaded bottom holes are provided on the second insulating layer, and the connecting screws are fixed in the mounting holes and the threaded bottom holes;

[0009] The diameter of the mounting hole is 5 mm and the thickness is 5 mm; the diameter of the threaded bottom hole is 5 mm and the thickness is 15 mm.

[0010] Furthermore, the cement mortar lining is prepared from portland cement or special cement, medium - fine sand, and mixing water, with the mud content ≤ 3%, the pH value of the mixing water being 6.5 - 8.5, the ratio of cement to sand being 1 - 1.3, and the water - cement ratio being 0.45 - 0.65.

[0011] Furthermore, the diameter of the cement mortar lining is 10 mm and the thickness is 5 mm; the diameter of the first insulating layer is 31 - 32 mm and the thickness is 5 mm; the diameter of the ductile iron electrode is 10 mm and the thickness is 20 mm; the diameter of the second insulating layer is 31 - 32 mm and the thickness is 20 mm.

[0012] Furthermore, the head groove type of the connecting screw is an internal hexagonal groove, with the width across flats being 3 mm and the depth being 6 mm.

[0013] Further, the working electrode further includes a conductor wiring, which is a rigid copper conductor wire and is provided with an insulating layer on its outer surface.

[0014] On the other hand, to achieve the above object, the present invention provides a method for using the above micro-region working electrode, including the following steps:

[0015] Obtain portland cement, medium sand and mixing water, and prepare a cement mortar lining by mechanical stirring method;

[0016] Put the cement mortar lining into a corrosive medium to simulate the erosion of the water supply pipe network environment; use a hard metal fine needle to perform periodic contact damage on the cement mortar lining to simulate the influence of pipeline cleaning and water hammer impact;

[0017] Pretreat the ductile iron electrode and weld the conductor wiring;

[0018] After precisely fitting the ductile iron electrode with the cement mortar lining, tighten the connecting screws by a cross-tightening method to complete the electrode preparation;

[0019] Connect the prepared working electrode to a conventional electrochemical electrolytic cell or a micro-region electrochemical electrolytic cell for simulation.

[0020] Further, the pretreatment of the ductile iron electrode includes:

[0021] When it is necessary to study the protection effect of the lining and the electro-chemical reaction mechanism under the condition of no corrosion of the metal, clean the oxide layer, oil stain or dust on the ductile iron electrode with anhydrous ethanol or acetone;

[0022] When studying the protection effect and the electro-chemical reaction mechanism after re-repairing the lining under the condition of metal corrosion after the lining falls off, immerse the ductile iron electrode in a corrosive medium to generate a corrosion scale layer.

[0023] Further, connecting the prepared working electrode to a conventional electrochemical electrolytic cell or a micro-region electrochemical electrolytic cell for simulation includes:

[0024] When connecting to a conventional electrochemical electrolytic cell, obtain corrosion data by conventional electrochemical means, and then analyze the protection mechanism and degradation mode of the cement mortar lining for the water supply pipeline throughout the life cycle;

[0025] When connecting to a micro-region electrochemical electrolytic cell, simulate the protection mechanism and degradation mode of the cement mortar lining for the water supply pipeline in different life cycles by micro-region electrochemical means, as well as the protection mechanism of the repaired lining for the corroded pipeline and the growth of the corrosion scale layer.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The present invention relates to a micro - area electrochemical working electrode for the failure of cement mortar lining in a water supply network, which can realize real - time electrochemical measurement of the entire service life cycle of the cement mortar lining in the water supply network, facilitating the study of the action mechanism and protection effect of the cement mortar lining on network corrosion under different life cycles, so as to more accurately simulate the actual operation conditions and anti - corrosion performance test of the cement mortar lining in the water supply network from the initial stage to the later stage.

[0028] 2. The working electrode of the present invention adopts a standardized preparation process to ensure consistent electrode size, controllable reaction area, improve repeatability, and the coating can simulate the protection effect on the metal electrode in different life cycles through methods such as thickness selection and defect preparation. Furthermore, the microstructure and properties of the corrosion scale of newly - put - into - use pipelines and old pipelines can be inferred, and the corrosion evolution process and electro - corrosion mechanism of water supply pipelines with cement mortar lining can be deeply studied, providing an important basis for the life prediction and corrosion protection of urban water supply pipelines.

[0029] 3. The working electrode of the present invention is compatible with two - electrode and three - electrode electrolysis systems, and can accurately characterize the corrosion characteristics in static and flowing systems through conventional electrochemical measurement methods such as alternating current impedance spectroscopy, potentiodynamic scanning, and open - circuit potential, so as to study the protection performance and failure engineering of the cement mortar lining in water supply pipelines.

[0030] 4. The working electrode of the present invention is compatible with a micro - area electrochemical test system, and can detect the local characteristics of corrosion reactions under lining damage with high resolution through techniques such as scanning vibrating electrode, scanning Kelvin probe, local electrochemical impedance spectroscopy, and scanning electrochemical microscopy, so as to deeply reveal the protection mechanism and failure mechanism of the cement mortar lining in water supply pipelines.

[0031] 5. The working electrode and the lining of the present invention are prepared separately, avoiding the complex process of integral preparation, making subsequent experimental operations of reusing the working electrode or replacing the lining based on the corrosion of the working electrode more convenient and fast, and better analyzing the anti - corrosion effect after lining repair of corroded pipelines in the water supply pipeline. Description of the Drawings

[0032] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered as limiting the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0033] Figure 1 It is a schematic 3D structure diagram of the micro - area electrochemical working electrode in the embodiment of the present invention;

[0034] Figure 2Schematic top view structure of the micro-area electrochemical working electrode in the embodiment of the present invention;

[0035] Figure 3 Schematic side view structure of the micro-area electrochemical working electrode in the embodiment of the present invention;

[0036] Figure 4 3D impedance diagram obtained from the measurement of the specific embodiment of the present invention;

[0037] The reference numerals are as follows:

[0038] 1 - Cement mortar lining; 2 - First insulating layer; 3 - Ductile iron electrode; 4 - Second insulating layer; 5 - Conductor connection; 6 - Connecting screw. Specific implementation mode

[0039] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be completely conveyed to those skilled in the art. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. Hereinafter, the present invention will be described in detail with reference to the drawings and in combination with the embodiments.

[0040] This embodiment provides a micro-area electrochemical working electrode for measuring the failure of cement mortar lining and its use method. As Figure 1 shown, it includes:

[0041] Cement mortar lining 1, on whose outer surface there is a first insulating layer 2, and the first insulating layer 2 is a PTFE insulating layer with an installation hole; the diameter of the cement mortar lining 1 is 10 mm and the thickness is 5 mm, the diameter of the first insulating layer 2 is 31 - 32 mm and the thickness is 5 mm; the diameter of the installation hole is 5 mm and the thickness is 5 mm. This working electrode further includes a ductile iron electrode 3, on whose outer surface there is a second insulating layer 4, and the second insulating layer 4 is a PTFE insulating layer provided with a threaded bottom hole; the lower surface of the electrode is provided with a hard copper conductor wire 5, and an insulating layer is provided on the outer surface of the hard copper conductor wire 5; the diameter of the ductile iron electrode 3 is 10 mm and the thickness is 20 mm; the diameter of the second insulating layer 4 is 31 - 32 mm and the thickness is 20 mm; the diameter of the threaded bottom hole is 5 mm and the thickness is 15 mm; the hard copper conductor wire is 10 - 15 cm long, with the end exposed and connected to an external conventional / micro-area electrochemical measurement device. The lining layer 2 is a sound or defective cement mortar lining layer.

[0042] As Figure 2As shown, the mounting holes in this embodiment are four circular mounting holes of the same size, arranged along the edge area of the first insulating layer 2 for screw fastening. They are located in the up-down and left-right directions respectively and are symmetrically distributed to optimize the structural balance and performance. These mounting holes are for screws to pass through and be screwed in to ensure the stable connection of the components.

[0043] A connecting screw 6 is provided in the mounting hole. The head groove type of the connecting screw 6 is an internal hexagonal groove, and its across flat width is 3 mm and the depth is 6 mm to fit the corresponding specification of the internal hexagonal wrench.

[0044] According to the experimental requirements, the cement mortar lining 1 can be a complete cement mortar lining layer, a partially worn cement mortar lining layer, or a completely worn cement mortar lining layer.

[0045] The corrosion medium required for the experiment is between the cement mortar lining 1 and the ductile iron electrode 3, with a thickness of 0.00 - 0.05 mm. Adjust the connecting screws according to the experimental requirements.

[0046] The side view of the working electrode in this embodiment is as Figure 3 shown, consisting of an upper cement mortar lining layer and a lower ductile iron metal layer. The preparation and treatment process of the cement mortar lining 1 depends on the experimental conditions.

[0047] It should be noted that when studying the initial stage of the use of the cement mortar lining 1, Portland cement or special cement that meets national standards (such as GB175 - 2007) should be adopted, medium-fine sand that meets the standard of GB / T14684 - 2011 should be selected, with a mud content ≤ 3% to avoid affecting the bondability and strength of the mortar. Mixing water that meets JGJ 63 - 2006 should be selected, with a pH value of 6.5 - 8.5 and no harmful impurities such as sulfates and chlorides. The proportioning scheme and coating requirements are as follows: admixtures such as plasticizers, waterproof agents, retarders, and reinforcing fibers are added according to the actual pipeline network and experimental requirements. The cement: sand ratio is 1 - 1.3, and the water-cement ratio is 0.45 - 0.65. Mechanical stirring is used to ensure the uniformity of the mortar. After mixing, let it stand for 5 - 10 minutes, and then apply the cement mortar to the lining layer. Use a flat scraper to remove the excess cement mortar so that the surface of the coating is at the same level as the outer edge of the insulating layer, and ensure that the mortar only covers the central large cylindrical area. After such treatment, it can ensure that the thickness of the mortar coating is consistent with the lining, reaching 5 mm, and at the same time make the surface of the exposed part uniform and smooth. In addition, the height of the outer edge of the insulating layer is fixed, which can be used as a reference for judging the change in the lining thickness. The prepared cement mortar lining layer is then placed in a constant temperature oven at 25°C for natural hardening and drying for 3 to 7 days to ensure sufficient curing and achieve the expected anti-corrosion performance.

[0048] When studying the failure process of the cement mortar lining 1, it is necessary to place the cured cement mortar lining layer into the corrosive medium to simulate the erosion of different water supply pipe network environments on the lining. A hard metal fine needle (load 1 - 10 N) is used to perform periodic contact damage on the cured cement mortar lining layer to simulate the effects of pipe cleaning and water hammer shock.

[0049] The metal electrode is a ductile iron cylindrical electrode. It should be noted that when studying the protection effect and electrochemical reaction mechanism of the lining without metal corrosion, if there is an oxide layer, oil stain or dust on the ductile iron layer, anhydrous ethanol or acetone can be used for cleaning to improve the experimental accuracy and reproducibility; when studying the protection effect and electrochemical reaction mechanism after repairing the lining when the metal corrodes after the lining falls off, if there is no corrosion scale layer on the ductile iron layer, it can be immersed in the corrosive medium to generate a real corrosion scale layer to simulate the real pipe network environment.

[0050] Subsequently, the lower cylindrical surface of the ductile iron electrode 3 is welded and connected to a hard copper conductor joint with a length of 10 cm. After welding, the outer layers of the lower surface and the copper conductor joint are coated with a PTFE insulating layer to effectively isolate the non-working area, prevent unexpected corrosion when the electrode is immersed in the electrolytic cell, and ensure the accuracy of the measured data. The end of the copper joint remains exposed to achieve a stable connection with the external electrochemical device.

[0051] Align the fabricated cement mortar lining layer with the ductile iron metal layer for precise fitting, and tighten the screws in turn using a cross-tightening method to ensure uniform stress. Ensure the screw fixing strength by torque control to avoid over-tightening or loosening.

[0052] Connect the fabricated working electrode to an external electrochemical measurement device. It can be externally connected to a conventional electrochemical electrolytic cell or a micro-area electrochemical electrolytic cell. Connect the electrolyte to the electrochemical workstation. Through conventional electrochemical means (measurement means such as open circuit potential, potentiodynamic scanning, alternating current impedance spectroscopy, strong and weak polarization, etc.), the corrosion data in a static or circulating flow environment can be accurately obtained, so as to construct a model and analyze the protection mechanism and degradation mode of the cement mortar lining for the water supply pipeline throughout its life cycle; through micro-area electrochemical means (techniques such as scanning vibrating electrode, scanning Kelvin probe, local electrochemical impedance spectroscopy, scanning electrochemical microscope, etc.), the protection mechanism and degradation mode of the cement mortar lining for the water supply pipeline at different life cycles and the protection mechanism of the corroded pipeline after lining repair and the growth of the corrosion scale layer can be accurately simulated.

[0053] Taking the above-mentioned ductile iron working electrodes with intact and damaged cement mortar layers as examples, the micro-area electrochemical differences of ductile iron water supply pipe networks with cement mortar linings under different life cycles were simulated to explore the failure process of the cement mortar lining from intact to damaged. The working electrode was connected to the micro-area electrochemical three-electrode system electrolytic cell, tap water was added to the electrolytic cell, and it was connected to the electrochemical workstation. The basic settings such as the material parameters of ductile iron and the experimental environment (constant temperature 25°C) were input, the measurement method was selected as local electrochemical impedance, and the silver / silver chloride (Ag / AgCl) electrode was used as the reference electrode. The alternating current was set with an amplitude of 10mV (relative to the open circuit potential). After the open circuit potential stabilized, the detection was started with a scanning frequency from 0.01 to 100000 Hz, and the local AC impedance spectra of ductile iron with intact and damaged cement mortar layers were obtained. The 3D graph of the measured impedance value is as follows Figure 4 As shown, the results show that the intact cement mortar lining has a larger impedance value, the impedance value of the damaged cement mortar lining is significantly reduced at the defect, and the protection of the cement mortar lining to the ductile iron fails, which is basically consistent with the results of the actual pipeline environment.

[0054] The present invention proposes a micro-area electrochemical working electrode for studying the failure of cement mortar lining in water supply pipe network, which can simulate the inner surface state of ductile iron pipe with cement mortar lining under the whole life cycle, improve the test accuracy, solve the problem that the protective effect of cement mortar lining under each life cycle cannot be fully simulated in the study of water supply pipe corrosion, and solve the problem that the electrochemical detection after lining repair cannot be carried out on the ductile iron pipe wall after corrosion has occurred. This makes it possible to study the corrosion process and corrosion mechanism of water supply pipe after long-term service, which is of great significance for the life assessment and corrosion protection of urban water supply pipe network. The preparation of lining is standardized, the measurement results are more accurate and reliable, the coating surface is flat and uniform, and the thickness is controllable, which can significantly improve the accuracy and repeatability of corrosion electrochemical measurement. The standardized electrode module makes different experiments comparable, reduces the data error caused by human factors, and improves the credibility of the experimental results. The materials and structural design selected by the working electrode of the present invention enable it to adapt to different water quality environments and pipeline material requirements. The insulating layer material (PTFE) is water-resistant and corrosion-resistant, and is not prone to aging and failure even in long-term use in corrosive media such as chloride ions; the metal electrode body can be replaced according to the actual pipeline material (such as steel, electrocast iron, etc.) to simulate the corrosion behavior of pipelines of different materials, and the lining is simulated according to the actual pipeline operation cycle and hydraulic characteristics. Due to the above design, this electrode can maintain good performance under various water supply quality conditions, significantly expanding its application range and improving the versatility of the experimental device.

[0055] The terms "first", "second", etc. in the description and claims of the present invention are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are usually of the same category, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / ", generally represents an "or" relationship between the associated objects before and after.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A micro-area working electrode for measuring cement mortar lining failure, characterized in that: It comprises a cement mortar lining (1), a ductile iron electrode (3) is arranged below the cement mortar lining (1), and a corrosive medium is arranged between the cement mortar lining (1) and the ductile iron electrode (3); A first insulating layer (2) is disposed on the periphery of the cement mortar lining (1), a second insulating layer (4) is disposed on the periphery of the ductile iron electrode (3), and the second insulating layer (4) is fixedly connected to the first insulating layer (2) via connecting screws (6).

2. The micro-area working electrode for measuring cement mortar lining failure according to claim 1, characterized in that: The first insulating layer (2) is provided with a mounting hole; the second insulating layer (4) is provided with a threaded bottom hole, and the connecting screw (6) is fixed in the mounting hole and the threaded bottom hole; The diameter of the mounting hole is 5 mm and the thickness is 5 mm; the diameter of the threaded bottom hole is 5 mm and the thickness is 15 mm.

3. The micro-area working electrode for measuring cement mortar lining failure according to claim 1, characterized in that: The cement mortar lining (1) is prepared by using silicate cement or special cement, medium-fine sand and mixing water, the amount of mud is ≤3%, the pH value of the mixing water is 6.5-8.5, the ratio of cement to sand is 1-1.3, and the water-cement ratio is 0.45-0.

65.

4. The micro-area working electrode for measuring cement mortar lining failure according to claim 1, characterized in that: The cement mortar lining (1) has a diameter of 10 mm and a thickness of 5 mm; the first insulating layer (2) has a diameter of 31-32 mm and a thickness of 5 mm; the ductile iron electrode (3) has a diameter of 10 mm and a thickness of 20 mm; the second insulating layer (4) has a diameter of 31-32 mm and a thickness of 20 mm.

5. The micro-area working electrode for measuring cement mortar lining failure according to claim 1, characterized in that: The head groove type of the connecting screw (6) is a hexagonal groove, the width across the sides is 3 mm, and the depth is 6 mm.

6. The micro-area working electrode for measuring cement mortar lining failure according to claim 1, characterized in that: It also comprises a conductor connection (5), wherein the conductor connection (5) is a hard copper conductor wire, and an insulating layer is provided on the outer surface.

7. A method for using the micro-area working electrode according to claims 1-6, characterized in that: include: Obtain silicate cement, Chinese and Western sand and mixing water, and prepare cement mortar lining (1) by mechanical mixing method; The cement mortar lining (1) is placed in a corrosive medium to simulate the erosion of the water supply network environment; a hard metal needle is used to perform periodic contact damage on the cement mortar lining (1) to simulate the impact of pipeline cleaning and water hammer impact; Pre-treating the ductile iron electrode (3) and welding the conductor connection (5); After the ductile iron electrode (3) and the cement mortar lining (1) are precisely fitted together, the connecting screws (6) are tightened in a cross-tightening manner to complete the electrode preparation; The prepared working electrode is connected to a conventional electrochemical cell or a micro-area electrochemical cell for simulation.

8. The method of use according to claim 7, characterized in that: The ductile iron electrode (3) is pretreated, comprising: When it is necessary to study the protective effect of the lining and the electrochemical reaction mechanism without metal corrosion, anhydrous ethanol or acetone is used to clean the oxide layer, oil stains or dust of the ductile iron electrode (3); When studying the protective effect and electrochemical reaction mechanism of the repaired lining in the case of metal corrosion after the lining falls off, the ductile iron electrode (3) is immersed in a corrosive medium to generate a corrosion scale layer.

9. The method of use according to claim 7, characterized in that: The prepared working electrode is connected to a conventional electrochemical cell or a micro-area electrochemical cell for simulation, including: When connected to a conventional electrochemical cell, corrosion data is obtained by conventional electrochemical means, and then the protection mechanism and degradation mode of cement mortar lining for water supply pipeline protection over the entire life cycle are analyzed; When an external micro-area electrochemical cell is connected, the protection mechanism and degradation mode of cement mortar lining for water supply pipes in different life cycles, as well as the protection mechanism of corroded pipes and the growth of corrosion scale layer after lining repair are simulated by micro-area electrochemical means.

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