An in-situ on-line monitoring device and monitoring method for aging state of organic coating

Abstract

The application discloses an organic coating aging state in-situ online monitoring device and a monitoring method. The device comprises an electrode pair, a multi-channel impedance test unit and a remote control unit connected with the multi-channel impedance test unit. The electrode pair is embedded in the base metal of the coating metal piece to be measured. The material of the electrode pair is the same as that of the base metal. One end of the electrode pair is in contact with the coating of the coating metal piece to be measured, and the other end is connected with the multi-channel impedance test unit. The multi-channel impedance test unit collects the coating impedance data of the coating metal piece to be measured and analyzes and obtains the calculation result. The remote control unit evaluates the aging state of the field service coating of the coating metal piece to be measured according to the calculation result. The application can obtain and master the performance change related information of the coating system in the actual service process in real time, can provide directional guidance for evaluating the aging state and degree of the coating at a specific position, reduces the detection time and improves the detection efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coating aging state monitoring, and particularly relates to an in-situ online monitoring device and a monitoring method for the aging state of an organic coating. BACKGROUND

[0002] With the deployment of China's marine strategy and the development of marine resources, the strategic significance of the vast regions of China's southern coast, islands, South China Sea, etc. is increasingly prominent. Key infrastructure construction such as island microgrids, offshore wind power, and port bridges is accelerating, providing support for China's strategic layout. The protection of these key infrastructures mainly adopts the method of physical isolation of the metal substrate and corrosive medium by anticorrosive coating. During use, the physical, chemical, and mechanical properties of the anticorrosive coating change irreversibly due to the influence of the environment, damaging some of the protective functions of the coating and losing protection for the component substrate, thereby affecting the overall safe use of the facility. How to quickly and scientifically evaluate the coating performance and state of the service components and equipment, and understand and master the corrosion aging failure of the coating under the action of various environmental stresses such as heat and humidity, ultraviolet light, salt spray, pollutants, and fatigue load, are all practical engineering technical problems that need to be solved urgently. Therefore, if the real-time changes of the coating in the actual service environment can be accurately grasped in a timely manner, it will be beneficial to the timely maintenance and treatment of the coating, greatly reducing costs.

[0003] Structural corrosion monitoring technology is very important at home and abroad. Electrochemical impedance testing is widely used for corrosion monitoring of facilities, components, or equipment due to its fast measurement speed and small disturbance to the structure. Currently, existing coating online monitoring methods mechanically place the coating online monitoring probe in the field service environment to collect monitoring data, without considering the actual structure of the facility, component, or equipment, because the coating process, coating and component or equipment substrate bonding method will affect the aging evolution of the coating in the actual service environment. SUMMARY

[0004] The first object of the present application is to provide an in-situ online monitoring device for the aging state of an organic coating, which has simple structure, good stability, and accurate test results, and is suitable for in-situ monitoring and state evaluation of the surface coating of infrastructure components and equipment about to be put into field service.

[0005] The first object of the present application is achieved by the following technical measures: an in-situ online monitoring device for the aging state of an organic coating layer, characterized in that it comprises an electrode pair, a multi-channel impedance testing unit, and a remote control unit connected to the multi-channel impedance testing unit, the electrode pair is used to be embedded in the base metal of the coating metal piece to be tested, the material of the electrode pair is the same as that of the base metal, one end of the electrode pair is in contact with the coating layer of the coating metal piece to be tested, and the other end is connected to the multi-channel impedance testing unit, the multi-channel impedance testing unit collects the coating impedance data of the coating metal piece to be tested and analyzes to obtain the calculation results, and the remote control unit evaluates the aging state of the coating layer of the coating metal piece to be tested in the field according to the calculation results.

[0006] The present application mainly uses the principle of impedance testing technology to monitor the aging state of the organic coating layer on the metal component or device in service in-situ online, can spread the coating aging monitoring points to different positions on the metal component or device, determine the coating aging degree at different positions through continuous and real-time monitoring, real-time acquire and master the performance change related information of the coating system in the actual service process, can provide directional guidance for evaluating the coating aging state and degree at specific positions, reduce the detection time, improve the detection efficiency, solve the environmental adaptability design and application problem of the corrosion protection technology, provide technical reference basis for the marine infrastructure engineering to screen long-acting corrosion protection coating system suitable for the actual service environment from various coatings, effectively guide the maintenance, maintenance and update of the coating by the related technical personnel of the power grid, ensure the safe and reliable operation of the components or devices of the marine infrastructure, and reduce the safety hidden danger and economic loss caused by coating failure.

[0007] The electrode pair of the present application comprises a columnar counter electrode, a ring-shaped working electrode, a grounding wire and an electrode external lead, a ring-shaped groove penetrating into the base metal and a mounting groove located at the center of the ring-shaped groove are opened on the coating metal piece to be tested, the counter electrode is arranged in the mounting groove and the gap between the counter electrode and the groove wall and groove bottom is filled with insulating material, the working electrode is arranged in the ring-shaped groove and the gap between the working electrode and the groove wall and groove bottom is filled with insulating material, one end of the grounding wire is connected to the base metal and the other end is grounded; one end of the electrode external lead is connected to the electrode pair and the other end is connected to the multi-channel impedance testing unit, and the annular part of the base metal between the working electrode and the counter electrode is a guard ring for reducing the coupling between the electrodes. In order to ensure the insulation of the working electrode and the counter electrode from the base metal, insulating material (preferably epoxy resin) is used to fill and seal in the ring-shaped groove and the mounting groove.

[0008] The multi-channel impedance testing unit of the present invention consists of a housing, a control panel disposed on the housing, a data acquisition module, an analysis module and a communication module built into the housing. The analysis module is connected to the data acquisition module, the communication module and the control panel respectively. The coated metal part under test is provided with an electrode interface for connecting the external wire of the electrode, and the electrode interface is provided with a shield.

[0009] The depths of the annular groove and the mounting groove described in this invention are the same as the thickness of the base metal.

[0010] The working electrode of this invention has a wall thickness of 8mm to 10mm and an outer ring diameter of 35mm to 45mm. The counter electrode has a diameter of 5mm to 10mm.

[0011] The electrode pair described in this invention has one end of the slot flush with the surface of the substrate metal.

[0012] The number of electrode pairs embedded is determined based on the area of ​​the coating system to be tested. In this invention, the effective coating area measured for each electrode pair is the coating area between the working electrode and the counter electrode, referred to as the test area. The area of ​​the effective coating area measured for each electrode pair is the test area area. Following the principle of uniform point distribution according to the area of ​​the coating system to be tested, the distance between the test area and the edge of the metal part to be tested is not less than 1 cm; when the single-sided area of ​​the metal part to be tested is less than or equal to 1 m²... 2 At least 5 electrode pairs should be set on this surface; when the single-sided area of ​​the coated metal part to be tested is greater than 1m², 2 And less than 5m 2 When the surface area of ​​the coated metal part to be tested is greater than or equal to 5m², 6 to 10 electrode pairs are set on this surface; 2 At that time, at least 10 electrode pairs are set on this surface.

[0013] The multi-channel impedance testing unit of this invention outputs a test disturbance sinusoidal AC signal through external electrode wires. The voltage range is 0.165V to 3.3V, and it automatically selects the disturbance amplitude with higher signal quality. The scanning frequency range is 0.1Hz to 100KHz.

[0014] The second objective of this invention is to provide a monitoring method for the above-mentioned organic coating aging state in-situ online monitoring device.

[0015] The second objective of this invention is achieved through the following technical measures: a monitoring method for the above-mentioned organic coating aging state in-situ online monitoring device, characterized by comprising the following steps:

[0016] S1. Accelerated environmental testing in the laboratory:

[0017] (1) Determine the environmental accelerated aging factors and environmental parameters of the field service environment of the coated metal parts to be tested;

[0018] 2. Using the same metal, paint and coating process as the coating metal piece to be tested to make a test plate with a coating on the surface of the metal plate;

[0019] 4. According to the environmental acceleration aging factors and environmental parameters, the laboratory accelerated environmental test condition parameters are set according to 10-100 times of the field environment equivalent;

[0020] 5. The in-situ online monitoring device for organic coating aging state is used to perform laboratory accelerated environmental test on the test plate, and in the test process, the coating impedance data of the test plate is collected, the change rule of the impedance modulus value of the coating from the initial state to the aging failure state is analyzed, the corresponding impedance equivalent circuit model is selected, the appearance change is combined to establish the coating aging state grading evaluation standard, and the impedance modulus value threshold at the coating failure is determined;

[0021] S2, using the in-situ online monitoring device for organic coating aging state to monitor the service state of the coating of the coating metal piece to be tested in real time:

[0022] 1. The impedance equivalent circuit model and the impedance modulus value threshold determined in step S1 are set in the remote control unit;

[0023] 2. The multi-channel impedance test unit collects the coating impedance data of the coating metal piece to be tested and analyzes the calculation results of the impedance modulus value in combination with the impedance equivalent circuit model;

[0024] 3. The remote control unit compares the calculation results with the set impedance modulus value threshold to evaluate the field service coating aging state of the coating metal piece to be tested, uploads the evaluation results to the client, and gives a warning or an alarm treatment when the evaluation results are close to or lower than the impedance modulus value threshold, respectively.

[0025] When the evaluation results are close to the impedance modulus value threshold, a warning prompt of the remote control unit is triggered, prompting the user that the service coating is about to age and fail, and preventive measures need to be taken in advance; when the evaluation results are lower than the impedance modulus value threshold, an alarm prompt of the remote control unit is triggered, warning the user that the service coating is in a failure state and loses the protection function of the base metal, and protective measures need to be taken immediately.

[0026] The coating aging state grading evaluation standard described in the application is that the impedance modulus value range is Z 0.1Hz ≥10 9 Ω·cm 2 Above, the coating state is excellent performance, and the grade is A; the impedance modulus value range is 10 8 ≤Z 0.1Hz <10 9 Ω·cm 2 , the coating state is good performance, and the grade is B; the impedance modulus value range is 107 ≤Z 0.1Hz <10 8 Ω·cm 2 , coating state is performance general, grade C; impedance module value range is 10 6 ≤Z 0.1Hz <10 7 Ω·cm 2 , coating state is performance poor, grade D; impedance module value range is Z 0.1Hz <10 6 Ω·cm 2 Below, coating state is performance failure, grade E.

[0027] Compared with the prior art, the present application has the following significant advantages:

[0028] (1) The present application mainly adopts impedance test technology principle, and the aging state of the organic coating on the metal component or equipment in service is monitored in situ and online. The coating aging monitoring points can be scattered to different positions on the metal component or equipment. The coating aging degree at different positions is determined by continuous and real-time monitoring. The performance change related information of the coating system in the actual service process can be obtained and mastered in real time. The direction of the coating aging state and degree of the specific position can be provided. The detection time is reduced, the detection efficiency is improved, the environmental adaptability design and application problem of the corrosion protection technology is solved. The technical reference basis is provided for the marine infrastructure engineering to select the long-acting corrosion protection coating system suitable for the actual service environment from various coatings. The maintenance, maintenance and updating of the coating by the related technical personnel of the power grid are effectively guided. The safe and reliable operation of the component or equipment of the marine infrastructure is ensured. The safety hidden danger and economic loss caused by the coating failure are reduced.

[0029] (2) The present application adopts a double electrode system + grounding mode. Unlike the traditional electrochemical impedance spectroscopy, the present application does not need a reference electrode and an electrolyte. The electrolytic solution gradually infiltrated into the organic coating in the service environment is used as the electrolyte of the test system. The electrodes are made of the same material as the base metal. The reaction mechanism of the coating aging change and the base metal corrosion change is reduced to the maximum. The error of the test result caused by the instability of the reference electrode is greatly reduced. Therefore, the present application has the advantages of simple device structure, good stability and high data reliability.

[0030] (3) The electrode pair of the present application is placed below the coating and directly coupled with the coating. Therefore, the electrode pair is very sensitive to the change of the coating performance state. The electrode pair is not exposed to the external environment and will not be affected by the external environment change to affect the accuracy of the monitoring data. The advantage of the design is that the electrode is completely isolated from the base metal material by the insulating material and has no electrical connection, and the integrity of the coating is not damaged. BRIEF DESCRIPTION OF DRAWINGS

[0031] The application will be further described in detail below with reference to the accompanying drawings.

[0032] Figure 1 is a schematic diagram of the structure of the online monitoring device of the application;

[0033] Figure 2 is a schematic diagram of the distribution of test points on the coated metal piece to be tested;

[0034] Figure 3 is a schematic diagram of the structure of one of the test point electrode pairs;

[0035] Figure 4 is a schematic diagram of the structure of the second of the test point electrode pairs;

[0036] Figure 5 is a flow chart of the monitoring method of the application. DETAILED DESCRIPTION

[0037] As Figures 1 to 4 shown, the online in-situ monitoring device for the aging state of an organic coating layer of the application comprises an electrode pair, a multi-channel impedance test unit 1, and a remote control unit 2 connected to the multi-channel impedance test unit 1. The electrode pair is used to be embedded in the base metal 4 of the coated metal piece 3 to be tested (coated metal member or equipment, including the base metal and the coating layer of the metal member or equipment). The material of the electrode pair is the same as that of the base metal 4. The upper end of the electrode pair is in contact with the coating layer 5 of the coated metal piece 3 to be tested, and the lower end is connected to the multi-channel impedance test unit 1. The multi-channel impedance test unit 1 collects the coating impedance data of the coated metal piece to be tested and analyzes and obtains the calculation results. The remote control unit 2 evaluates the in-situ service coating aging state of the coated metal piece to be tested according to the calculation results.

[0038] The electrode pair includes a columnar counter electrode 6, a ring-shaped working electrode 7, a grounding wire 8 and an electrode external wire 9. The wall thickness of the working electrode 7 is 8-10 mm, and the outer ring diameter is 35-45 mm. The diameter of the counter electrode 6 is 5-10 mm. A ring-shaped groove penetrating the base metal and a mounting groove located at the center of the ring-shaped groove are formed on the coated metal piece 3 to be measured. The depths of the ring-shaped groove and the mounting groove are the same as the thickness of the base metal. The counter electrode 6 is arranged in the mounting groove, and the gap between the counter electrode 6 and the groove wall and groove bottom is filled with epoxy resin 11. The working electrode 7 is arranged in the ring-shaped groove, and the gap between the working electrode 7 and the groove wall and groove bottom is filled with epoxy resin 11. The counter electrode 6 is flush with the surface of the base metal at one end of the mounting groove, and the working electrode 7 is flush with the surface of the base metal at one end of the ring-shaped groove. One end of the grounding wire 8 is connected to the base metal 4, and the other end is grounded. One end of the electrode external wire 9 is connected to the electrode pair, and the other end is connected to the multi-channel impedance test unit 1. An electrode interface for connecting the electrode external wire is arranged on the coated metal piece 3 to be measured, and a shielding cover is arranged on the electrode interface. The annular part of the base metal 4 between the working electrode 7 and the counter electrode 6 is a guard ring 10 for reducing the coupling between the electrodes.

[0039] The multi-channel impedance test unit 1 is composed of a shell, a control panel arranged on the shell, a data acquisition module, an analysis module and a communication module built-in the shell. The analysis module is connected with the data acquisition module, the communication module and the control panel, wherein the analysis module performs fitting analysis and calculation on the coating impedance data collected by the data acquisition module. The remote control unit 2 is composed of a server, a monitoring management system software and a communication module, which performs trend analysis or screening or grading on the fitting analysis and calculation results. The number of impedance test channels of the multi-channel impedance test unit is determined by the number of test electrode pairs. The multi-channel impedance test unit 1 outputs a test disturbance sinusoidal alternating current signal through the electrode external wire 9, the voltage range of which is 0.165 V-3.3 V, and automatically selects a disturbance amplitude with higher signal quality, and the scanning frequency range is 0.1 Hz-100 KHz.

[0040] The number of embedded working electrodes and counter electrodes is determined by the area of the coating system to be measured. The effective coating area measured by the electrode pair is the coating area between the working electrode and the counter electrode, which is called the test area. The effective coating area is the test area. According to the area of the coating system to be measured, the test area is arranged following the principle of uniform distribution, and the distance between the test area and the edge of the coated metal piece to be measured is not less than 1 cm. When the area of one side of the coated metal piece to be measured is less than or equal to 1 m 2 , at least 5 electrode pairs are arranged on the side; when the area of one side of the coated metal piece to be measured is greater than 1 m 2 and less than 5 m 2 , 6-10 electrode pairs are arranged on the side; when the area of one side of the coated metal piece to be measured is greater than or equal to 5 m 2At that time, at least 10 electrode pairs are set on this surface.

[0041] Installation process of this invention:

[0042] 1. Before installation and use, the annular groove and mounting groove for embedding the electrode pair should be pre-processed on the coated metal component or equipment to be tested. The depth of the annular groove and mounting groove should be consistent with the thickness of the base metal.

[0043] 2. Embed the working electrode and counter electrode into the annular groove and mounting groove respectively. To ensure that the working electrode and counter electrode are insulated from the substrate metal, seal the grooves with epoxy resin. Select a location on the exposed substrate metal area of ​​the metal component or equipment to be tested and connect it to the ground using a grounding wire.

[0044] 3. Add a protective ring between the working electrode and the counter electrode to reduce inter-electrode coupling. This protective ring can be added separately or it can be a ring-shaped portion of the base metal located between the working electrode and the counter electrode.

[0045] 4. Grind the entire surface of the component or equipment with the embedded electrodes until it is smooth, and then coat the component or equipment.

[0046] 5. Install the painted components or equipment on site, connect the external electrode wires to the multi-channel impedance testing unit, and connect the grounding wire to the ground.

[0047] 6. Install a shielding cover on the electrode interface for shielding and protection.

[0048] 7. Before monitoring begins, relevant parameters are input through the remote control unit to conduct on-site monitoring of the coating condition. The communication module between the remote control unit and the multi-channel impedance testing unit transmits data between them via wired or wireless means, using dedicated or general-purpose media. The multi-channel impedance testing unit locally caches the measurement results and transmits them to the remote control unit for user storage and use.

[0049] 8. From the moment of installation, the multi-channel impedance testing unit will test and record the impedance of the coating between electrodes according to the set testing cycle, continuing throughout the entire evaluation cycle.

[0050] like Figure 5 As shown, a monitoring method for an in-situ online monitoring device for the aging state of the above-mentioned organic coating includes the following steps:

[0051] S1. Accelerated environmental testing in the laboratory:

[0052] (1) Monitor the on-site service environment parameters of coated components or facilities to determine the environmental accelerated aging factors and environmental parameters of the on-site service environment of the coated metal parts to be tested;

[0053] 2. Using the same metal, paint and coating process as the coated metal part to be tested to make a test plate with a coated surface on a metal plate;

[0054] 4. According to the environmental acceleration aging factors and environmental parameters, the laboratory accelerated environmental test parameters are set at 10-100 times the equivalent of the field environment;

[0055] 5. The test plate is subjected to laboratory accelerated environmental testing using an in-situ online monitoring device for organic coating aging state, during the test, the coating impedance data of the test plate is collected, the change rule of the impedance modulus value of the coating from the initial state to the aging failure state is analyzed, the corresponding impedance equivalent circuit model is selected, and the coating aging state grading evaluation standard is established combined with the appearance change, and the impedance modulus value threshold at the coating failure is determined;

[0056] The formula for calculating the impedance modulus value is:

[0057]

[0058] In the formula, R c - coating resistance; C c - coating capacitance, Rs- solution resistance; ω- angular frequency.

[0059] The coating aging state grading evaluation standard is based on the premise that the coating impedance modulus value is consistent with the appearance (loss of luster, color difference value, degree of powdering, etc.).

[0060] S2, using an in-situ online monitoring device for organic coating aging state to monitor the coating service state of the coated metal part to be tested in real time:

[0061] 1. Before the service component or equipment is put into use, the electrodes of the monitoring device of the application are embedded in advance at the beginning of the design. Before real-time in-situ monitoring, the sine AC signal voltage value, sweep frequency range, monitoring interval length, impedance equivalent circuit model, impedance modulus value threshold and early warning threshold are set in the remote control unit.

[0062] 2. The multi-channel impedance test unit collects the coating impedance data of the coated metal part to be tested and analyzes the calculation results of the impedance modulus value combined with the impedance equivalent circuit model;

[0063] 3. The remote control unit compares the calculation results with the set impedance modulus value threshold to evaluate the in-situ service coating aging state of the coated metal part to be tested, and uploads the evaluation results to the client, so that the user can timely master the current state information of the coating at the remote end, and the evaluation results close to or below the impedance modulus value threshold are respectively given early warning or alarm processing.

[0064] For reaching the pre-warning threshold of the set near characteristic impedance value, the pre-warning prompt of the remote control unit will be triggered, prompting the user that the service coating is about to age and fail, and preventive measures need to be taken in advance; for being below the alarm threshold of the set near characteristic impedance value, the alarm prompt of the remote control unit will be triggered, warning the user that the service coating has been in a failure state, losing the protection function of the base metal, and protective measures need to be taken immediately.

[0065] Example:

[0066] The steel structure foundation bearing platform of a certain offshore wind turbine needs to replace part of the components due to service life problems, and hopes to monitor and evaluate the state of the component surface coating online in situ to guide technicians in daily maintenance and maintenance.

[0067] The monitoring device installation and monitoring method of the present example specifically includes:

[0068] S1, obtain the structure size, base material, coating type, coating thickness, coating process, and related information of the area and position to be measured of the new component;

[0069] S2, according to the component area, layout the monitoring position in advance on the component without coating, and process the ring-shaped groove and mounting groove of the embedded electrode pair in these positions in advance, the depth of the ring-shaped groove and mounting groove is consistent with the thickness of the component base metal. If the single-sided area of the component is less than 1m 2 , at least 5 embedded positions of test points are reserved.

[0070] S2-1, the base metal material of the component is carbon steel, so the working electrode is made of a carbon steel ring with a ring thickness of 8mm, and the outer ring diameter is controlled at 37mm, and the counter electrode is made of a carbon steel solid round bar with a diameter of 5mm. In order to ensure the insulation of the working electrode, the counter electrode and the base metal, the ring-shaped groove and the mounting groove are sealed by injecting epoxy resin. One end of each electrode pair is flush with the surface of the base metal, and the other end is led out through the electrode external lead wire. Then, the ring inside and outside the component electrode pair are respectively grounded.

[0071] S2-2, a protective ring is added between each pair of working electrodes and counter electrodes to reduce the coupling between electrodes.

[0072] S2-3, the surface of the component with embedded electrodes is polished to be flat, and then the component is coated according to the established coating process for use.

[0073] S3, at the same time, the key accelerated aging factors and specific environmental parameter contents in the field service environment that affect the coating state and performance of the component to be put into use are determined by monitoring the field service environment parameters.

[0074] S4, according to the information obtained in S1 and the reference S2, a micro-unit monitoring device is designed, including a coated structural member, a working electrode, a counter electrode, two grounding devices, an impedance test module, a data transmission unit, a remote management module and a shield.

[0075] S5, according to step S3, the test parameters of the laboratory accelerated test are set according to 10 times to 100 times of the equivalent level of the field environment, and the coating aging state of the micro-unit device is continuously monitored in situ during the test, the change rule of the low-frequency impedance modulus of the surface coating of the member from the initial state to the aging failure state is studied, the corresponding impedance equivalent circuit model is selected, and the coating aging state grading evaluation standard is established combined with the appearance change, as shown in the following table:

[0076] Rank Z 0.1Hz Impedance range / (Ω·cm 2 )]]> Coating Condition A 10 9 The above]] Excellent Performance B 10 9 ~10 8 ]] Good Performance C 10 8 ~10 7 ]] Fair Performance D 10 7 ~10 6 ]] Poor Performance E 10 6 following]]> Performance Failure

[0077] (Table 1)

[0078] S6, the coated member is installed on site according to the specified requirements, and the wires at the electrode interface of the coating plate are connected to the multi-channel impedance test unit, and the grounding wire is grounded.

[0079] S6-1, a shield is arranged at the corresponding position of the electrode interface side of the coating plate for noise shielding and protection.

[0080] S7, before starting the monitoring, the relevant test parameters are input through the remote control unit: ① the range of applied sinusoidal alternating signal voltage is 0.165V-3.3V; ② the frequency sweep range is 0.1Hz-100KHz; ③ the monitoring interval is 1 week / time; failure threshold, equivalent circuit model, early warning threshold, etc.

[0081] S7-1, the multi-channel impedance test unit locally caches the measurement results and transmits them to the remote control unit for user storage and use.

[0082] S7-2, starting from the installation, the multi-channel impedance test unit detects and records the coating impedance between the electrodes according to the set detection period, and continues throughout the evaluation period until the early warning signal appears, and necessary maintenance measures need to be taken in advance to avoid coating failure of the member and cause corrosion of the carbon steel substrate, thereby affecting the safe operation of the platform.

Claims

1. An in-situ online monitoring device for the aging state of an organic coating, characterized in that: It includes an electrode pair, a multi-channel impedance testing unit, and a remote control unit connected to the multi-channel impedance testing unit. The electrode pair is embedded in the base metal of the coated metal part under test. The material of the electrode pair is the same as that of the base metal. One end of the electrode pair is in contact with the coating of the coated metal part under test, and the other end is connected to the multi-channel impedance testing unit. The multi-channel impedance testing unit collects the coating impedance data of the coated metal part under test and analyzes it to obtain calculation results. The remote control unit evaluates the aging status of the coating of the coated metal part under test in field service based on the calculation results. The electrode pair includes a columnar counter electrode, an annular working electrode, a grounding wire, and an external electrode connecting wire. An annular groove extending into the substrate metal and a mounting groove located at the center of the annular groove are formed on the coated metal part under test. The counter electrode is disposed in the mounting groove, and the gap between it and the groove wall and bottom is filled with insulating material. The working electrode is disposed in the annular groove, and the gap between it and the groove wall and bottom is filled with insulating material. One end of the grounding wire is connected to the substrate metal, and the other end is grounded. One end of the external electrode connecting wire is connected to the electrode pair, and the other end is connected to the multi-channel impedance testing unit. The annular portion of the substrate metal between the working electrode and the counter electrode is a protective ring used to reduce inter-electrode coupling.

2. The in-situ online monitoring device for the aging state of organic coatings according to claim 1, characterized in that: The multi-channel impedance testing unit consists of a housing, a control panel mounted on the housing, a data acquisition module, an analysis module, and a communication module built into the housing. The analysis module is connected to the data acquisition module, the communication module, and the control panel, respectively.

3. The in-situ online monitoring device for the aging state of organic coatings according to claim 2, characterized in that: The metal part to be tested is provided with an electrode interface for connecting external wires of the electrode, and the electrode interface is provided with a shield.

4. The in-situ online monitoring device for the aging state of organic coatings according to claim 3, characterized in that: The depth of both the annular groove and the mounting groove is the same as the thickness of the base metal; the electrode pair is flush with the surface of the base metal at one end of the groove opening.

5. The in-situ online monitoring device for the aging state of organic coatings according to claim 4, characterized in that: The working electrode has a wall thickness of 8mm to 10mm and an outer ring diameter of 35mm to 45mm; the counter electrode has a diameter of 5mm to 10mm.

6. The in-situ online monitoring device for the aging state of organic coatings according to claim 5, characterized in that: The effective coating area for measurement by the electrode pair is the coating area between the working electrode and the counter electrode, referred to as the test area. The distance between the test area and the edge of the coated metal part under test is not less than 1 cm. When the single-sided area of ​​the coated metal part under test is less than or equal to 1 m², the measurement is performed within this area. 2 At least 5 electrode pairs should be set on this surface; when the single-sided area of ​​the coated metal part to be tested is greater than 1 m², 2 and less than 5 m 2 When the surface area of ​​the coated metal part to be tested is greater than or equal to 5m², 6 to 10 electrode pairs are set on this surface; 2 At that time, at least 10 electrode pairs are set on this surface.

7. The in-situ online monitoring device for the aging state of organic coatings according to claim 6, characterized in that: The multi-channel impedance testing unit outputs a test disturbance sinusoidal AC signal through external electrode wires. The voltage range is 0.165V~3.3V, and it automatically selects the disturbance amplitude with higher signal quality. The scanning frequency range is 0.1Hz~100KHz.

8. A monitoring method for the in-situ online monitoring device for the aging state of organic coatings as described in claim 1, characterized in that... Includes the following steps: S1. Accelerated environmental testing in the laboratory: (1) Determine the environmental accelerated aging factors and environmental parameters of the field service environment of the coated metal parts to be tested; (2) Prepare test plates with coatings on the surface of metal plates using the same metal, paint and coating process as the metal parts to be tested; (3) Based on environmental accelerated aging factors and environmental parameters, set laboratory accelerated environmental test parameters at 10 to 100 times the on-site environmental equivalent. (4) The test plates were subjected to laboratory accelerated environmental testing using an in-situ online monitoring device for the aging state of organic coatings. During the test, the coating impedance data of the test plates were collected, the change law of impedance modulus value from the initial state to the aging failure state of the coating was analyzed, the corresponding impedance equivalent circuit model was selected, and the coating aging state classification evaluation standard was established in combination with the appearance changes to determine the impedance modulus value threshold when the coating fails. S2. Use an in-situ online monitoring device for the aging state of organic coatings to perform in-situ real-time monitoring of the service status of the coating on the metal parts to be tested: (1) Set the impedance equivalent circuit model and impedance magnitude threshold determined in step S1 in the remote control unit; (2) The multi-channel impedance testing unit collects the coating impedance data of the coated metal part under test and analyzes it in combination with the impedance equivalent circuit model to obtain the calculated impedance magnitude. (3) The remote control unit compares the calculation results with the set impedance modulus threshold to assess the aging status of the coating on the metal part to be tested during field service, and uploads the assessment results to the client. If the assessment results are close to or below the impedance modulus threshold, a warning or alarm will be issued respectively.

9. The monitoring method according to claim 8, characterized in that: The coating aging state grading evaluation standard is: impedance modulus range of Z. 0.1Hz ≥10 9 Ω·cm 2 The coating condition is excellent, grade A; the impedance modulus range is 10. 8 ≤ Z 0.1Hz <10 9 Ω·cm 2 The coating condition is good, grade B; the impedance modulus range is 10. 7 ≤ Z 0.1Hz <10 8 Ω·cm 2 The coating condition is general performance, grade C; the impedance modulus range is 10. 6 ≤Z 0.1Hz <10 7 Ω·cm 2 The coating condition is poor, grade D; the impedance modulus range is Z. 0.1Hz < 10 6 Ω·cm 2 The following coating condition indicates performance failure, grade E.

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