CN116698926B - Measuring device and method for monitoring damage degree and corrosion rate of damaged part of coating - Google Patents

Abstract

The present invention discloses a measuring device and a measuring method for monitoring the degree of damage to a coating and the corrosion rate at a damaged part. A sensor for monitoring the degree of damage to a coating and the corrosion rate at a damaged part comprises a conductive shell, a plurality of electrodes, a temperature measuring element and a filling glue, wherein the plurality of electrodes are evenly distributed at the opening of the shell and are not in contact with the shell; the temperature measuring element can monitor the temperature change of the electrode in real time, the temperature measuring element is arranged on the side of the electrode facing away from the coating, and the temperature measuring element and the electrode are insulated; the filling glue can fix the electrode and the temperature measuring element inside the shell. The measuring device and the measuring method for monitoring the degree of damage to a coating and the corrosion rate at a damaged part disclosed by the present invention can more accurately judge the water seepage of the coating; at the same time, combined with the analysis of noise signals, it can predict the risk of damage faced by the coating earlier through the noise fluctuations of the potential and current on the basis of discovering the damage to the coating, and discover the aging trend of the coating.

Description

Measuring device and method for monitoring coating damage degree and corrosion rate at damaged parts

Technical Field

The invention relates to the field of intelligent measurement and control devices, and in particular to a measuring device and a measuring method for monitoring the degree of coating damage and the corrosion rate of a damaged part.

Background technique

Steel structures in the marine environment have been subjected to long-term erosion by seawater and impacts by waves, marine organisms and various floating objects on the sea surface, resulting in extremely serious corrosion damage. At present, various metal coatings are widely used on the surface of steel structures in the marine environment, showing good corrosion resistance. Although the metal coating plays a role in protecting the steel structure, the corrosion behavior is still ongoing. Once the coating is damaged, a tiny gap will be formed between the damaged coating and the metal substrate. The cathode shielding effect will occur inside the gap and the complete cathodic protection will not be obtained. The corrosive medium will directly corrode the substrate, and then cause severe local corrosion at the damaged part, resulting in a reduction in the strength of the steel structure. Once certain key parts have openings or damage, it will cause serious marine damage accidents. Therefore, it is of great significance to grasp the corrosion state of the coating in a timely manner.

At present, the corrosion condition of marine steel structures is usually inspected regularly, but corrosion occurs continuously. Corrosion safety problems that occur between two inspections are often not easy to detect. Due to the long inspection cycle and limited inspection items, the degree of coating damage and corrosion rate cannot be reflected, and online monitoring cannot be achieved.

Chinese patent CN202210611417.6 discloses a sensor and monitoring method for monitoring the coating peeling depth and corrosion state at the damaged part. By setting a multi-electrode coupling current measurement circuit and a multi-partition resistance method measurement circuit, the corrosion position of the coating is identified under the action of the multi-electrode coupling current measurement circuit, and the circuit is switched to the multi-partition resistance method measurement circuit after reaching the corrosion position. By detecting the voltage conditions at different positions of the measurement sensitive element, the corrosion conditions in different areas of the corrosion position are judged, thereby monitoring the peeling depth of the coating of the offshore wind power equipment. However, the sensor adopts an array of long strip resistor electrode structures, and judges the degree of coating damage by measuring the coupling current values of adjacent resistor test pieces, and cannot predict the risk of coating damage in advance.

Summary of the invention

The present invention provides a measuring device and a measuring method for monitoring the damage degree of a coating and the corrosion rate at a damaged part, so as to overcome the problem that the prior art can only detect coating damage but cannot predict in advance the damage risk faced by the coating.

In order to achieve the above-mentioned purpose, the technical scheme of the present invention is: a sensor for monitoring the degree of damage of a coating and the corrosion rate at a damaged part, comprising a conductive shell, a plurality of electrodes, a temperature measuring element and a filling glue, wherein the shell has a cavity with an opening on one side, the plurality of electrodes are evenly distributed at the opening of the shell and do not contact the shell, the opening end of the shell faces the coating to be measured, and the surface of the electrode contacts the surface of the coating to be measured;

The temperature measuring element can monitor the temperature change of the electrode in real time. The temperature measuring element is arranged on the side of the electrode facing away from the coating. The temperature measuring element and the electrode are insulated. The filling glue can fix the electrode and the temperature measuring element inside the shell.

Furthermore, the electrode includes a plurality of parallel and spaced horizontal segments, a return segment is arranged between adjacent horizontal segments, adjacent horizontal segments are arranged on the same side of the return segment, adjacent return segments are arranged on opposite sides of the horizontal segment, and the interval between adjacent return segments is equal to the length of the corresponding horizontal segment.

Furthermore, the distance between adjacent electrodes is equal to the distance between the electrode end and the inner wall of the shell, and the distance between adjacent electrodes does not exceed 0.5 mm.

Furthermore, a thermally conductive silicone pad is provided between the temperature measuring element and the electrode.

In order to achieve the above-mentioned purpose, the technical solution of the present invention also includes: a measuring device for monitoring the degree of damage of the coating and the corrosion rate of the damaged part, comprising a waterproof sealed chamber with a cavity, a sensor, a cable, an electrochemical detection system and a fixing glue, wherein the sensor is fixedly arranged outside the waterproof sealed chamber, the electrochemical detection system is fixedly arranged inside the waterproof sealed chamber by the fixing glue, and the sensor and the electrochemical detection system are electrically connected by a cable;

The electrochemical detection system comprises an electrochemical impedance spectrum measurement module, an electrochemical noise module and a multi-partition resistance measurement module, which are connected in parallel and electrically connected to a sensor.

Furthermore, a fixing lug is fixedly provided on the outside of the waterproof sealed chamber, and the fixing lug can fix the measuring device at a position to be detected.

Furthermore, the electrochemical impedance spectroscopy measurement module has three first wiring ports, each of which is connected to a first relay, and the electrochemical impedance spectroscopy measurement module is connected to the sensor via the first relay;

The electrochemical noise module has three second wiring ports, each of which is connected to a second relay, and the electrochemical noise module is connected to the sensor via the second relay;

The multi-partition resistance measurement module has four external interfaces, including two current interfaces and two voltage interfaces, each of the external interfaces is respectively connected to a third relay, and the multi-partition resistance measurement module is connected to the sensor via the third relay.

Furthermore, a plurality of current binding posts and a plurality of voltage binding posts are arranged between the third relay and the electrode, and the current binding posts and the voltage binding posts are arranged at intervals from each other;

A plurality of conductive contacts are evenly distributed on the electrode, and any conductive contact is connected to the current terminal and/or the voltage terminal. The plurality of conductive contacts divide the electrode surface into a plurality of partitions.

In order to achieve the above object, the technical solution of the present invention also includes: a method for testing the water seepage inside the coating or the degree of damage to the coating based on the measuring device, comprising the following steps:

Close the electrochemical impedance spectroscopy measurement module, control the electrochemical impedance spectroscopy measurement module to perform measurement, and analyze the acquired data, and analyze the water seepage inside the coating by calculating the capacitance between the two electrodes;

Or close the electrochemical noise module, control the electrochemical noise module to measure, and analyze the obtained data, analyze the current noise signal between the two electrodes and the potential noise signal between the electrode and the shell to obtain the damage degree information of the electrode surface coating.

In order to achieve the above object, the technical solution of the present invention also includes: a method for testing the metal corrosion rate based on the measuring device, comprising the following steps:

S1: Fix the measuring device at the position to be detected and measure the surface temperature data of the sensor through the temperature measuring element;

S2: Close the multi-partition resistance measurement module to measure the local resistance changes of the two electrodes respectively; analyze the data of the resistance measurement module, and calculate the metal corrosion rate of each partition in combination with the temperature measurement result of step S1.

In summary, the present invention has the following beneficial effects:

1. The present invention adopts an electrochemical impedance spectroscopy measurement module to monitor the water seepage inside the coating in real time, and combines it with an electrochemical noise module to collect coating surface damage information, thereby realizing coating damage monitoring and risk estimation.

2. In the present invention, a multi-partition resistance measurement module is preferably used to monitor the local resistance of each partition between electrodes, and the influence of temperature on the resistance change is corrected based on the temperature measurement result to improve the reliability of the corrosion rate calculation result.

By improving the form of the electrode, the present application can carry out electrochemical impedance testing, which can more accurately determine the water permeability of the coating; at the same time, combined with the analysis of noise signals, the risk of damage faced by the coating can be predicted earlier through the noise fluctuations of potential and current, and the aging trend of the coating can be discovered earlier, rather than simply discovering coating damage.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

FIG1 is a schematic diagram of the overall structure of a measuring device disclosed in the present invention;

FIG2 is a schematic diagram showing the internal structure of a sensor in the measuring device disclosed in the present invention;

FIG3 is a schematic structural diagram showing the positional relationship between two electrodes in the sensor disclosed in the present invention;

FIG4 is a schematic diagram of electrical wiring of an electrochemical impedance spectroscopy measurement module disclosed in the present invention;

FIG5 is a schematic diagram of electrical wiring of an electrochemical noise module disclosed in the present invention;

FIG6 is a schematic diagram of electrical wiring of a resistance measurement module disclosed in the present invention;

FIG7 is a flow chart of the steps of the measurement method disclosed in Example 2 of the present invention;

FIG8 is a flow chart of the steps of the measurement method disclosed in Example 3 of the present invention;

FIG9 is a flow chart of the steps of the measurement method disclosed in Example 4 of the present invention;

FIG. 10 is a flow chart of the steps of the measurement method disclosed in Example 5 of the present invention.

In the figure: 1. Waterproof sealing chamber; 2. Sensor; 21. Shell; 22. Electrode; 221. Horizontal section; 222. Folding section; 23. Temperature probe; 24. Filling glue; 3. Electrochemical detection system; 31. Electrochemical impedance spectroscopy measurement module; 32. Electrochemical noise module; 33. Multi-partition resistance measurement module; 34. Temperature measurement module; 35. Power module; 36. Communication module; 4. Fixing glue; 5. Underwater cable connector; 6. Fixing ear; 7. Organic coating; 8. Wire; 9. Thermal conductive silicone pad.

Detailed ways

In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with Figures 1-10 in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Example 1

In conjunction with Figures 1 and 2, a measuring device for monitoring the degree of coating damage and the corrosion rate at the damaged part includes a waterproof sealed chamber with a cavity, a sensor, an electrochemical detection system, and a fixing glue. The sensor is fixed to the outside of the waterproof sealed chamber by welding, and the electrochemical detection system is fixed to the inside of the waterproof sealed chamber by fixing glue. An underwater cable connector is left on the side wall of the waterproof sealed chamber.

The waterproof sealed chamber is a box body with an upper opening, a cover plate is provided at the opening of the waterproof sealed chamber, and the cover plate and the waterproof sealed chamber body are connected by bolts. A fixed hanging ear is welded on the side of the waterproof sealed chamber facing the steel structure, and the fixed hanging ear can be fixed to the position to be detected on the steel structure by bolts to achieve the fixation and installation of the measuring device.

2 and 3 , the sensor includes a conductive shell, two electrodes, a temperature measuring element and a filling glue. The shell is a box body made of titanium alloy with an opening on one side. The shell is fixed on the waterproof sealing chamber by welding, and the open end of the shell faces the object to be detected.

The two electrodes are both arranged at the open end of the shell, and the materials of the two electrodes are consistent with the materials of the object to be detected. The upper surfaces of the two electrodes are coated with an organic coating. The organic coating is formed by applying an organic coating or plastic on the measuring element by brushing, dipping, spraying, electrophoretic coating or electrostatic spraying, and the organic coating is formed after curing, thereby simulating the surface coating state of an actual marine structure.

The two electrodes are exactly the same in size, and the electrodes include three parallel and spaced horizontal segments, a folded segment is arranged between adjacent horizontal segments, adjacent horizontal segments are arranged on the same side of the same folded segment, adjacent folded segments are arranged on opposite sides of the same horizontal segment, and the interval between adjacent folded segments is equal to the length of the corresponding horizontal segment, so that the electrode has a Z-shaped structure, the two electrodes are folded in a Z-shape and arranged at the open end of the shell, the distance between the two electrodes is equal to the distance between the electrode end and the inner wall of the shell, and the distance between the two electrodes does not exceed 0.5 mm, so as to ensure a smaller spacing and a larger contact area, and can enhance the current measurement signal.

The two electrodes and the bottom of the shell are respectively connected with wires, and wires are respectively arranged at both ends of the two electrodes. The two electrodes are connected in series. After the series connection, the wires of the electrodes and the wires of the shell are respectively extended to the inside of the waterproof sealed chamber and connected to the electrochemical detection system inside the waterproof sealed chamber.

The temperature measuring element is preferably a temperature probe, and the temperature measuring element is located on the side of the electrode away from the organic coating, and can monitor the temperature change of the electrode in real time. A thermally conductive silicone pad is arranged between the temperature measuring element and the electrode to realize the insulation setting of the temperature measuring element and the electrode. The filling glue is filled in the interior of the shell, and the filling glue is preferably an epoxy resin filling glue. The cured epoxy resin filling glue realizes the positioning of the temperature measuring element, the thermally conductive silicone pad, the wire and the electrode. The lower end of the temperature measuring element is also connected to a wire, which extends downward to the outside of the shell. The temperature measuring element can perform thermoelectric conversion, and can convert the collected temperature information into an electrical signal, which is transmitted through the wire, so as to facilitate the collection of temperature information.

3 , the electrochemical detection system includes an electrochemical impedance spectroscopy measurement module, an electrochemical noise module, a multi-partition resistance measurement module, a temperature measurement module, a power supply module and a communication module. The temperature measurement module and the multi-partition resistance measurement module are connected in series with the electrochemical impedance spectroscopy measurement module and the electrochemical noise module to form a parallel circuit. The parallel circuit, the power supply module and the communication module are connected in series to form a series circuit. The series circuit is connected to an underwater cable connector to realize power supply to each module and to realize external transmission of collected signals from each module.

4 , the electrochemical impedance spectroscopy measurement module has three first wiring ports, which are respectively denoted as WE, CE and RE ₁ , and each first wiring port is respectively connected to a first relay, which are respectively denoted as A ₁ , A ₂ and A3 , wherein WE is connected to one end of the electrode through A ₁ through a wire, RE ₁ is connected to the other electrode through A ₃ through a wire, and CE is connected to the shell through A ₂ through a wire.

Referring to Figure 5, the electrochemical noise module has three second wiring ports, which are respectively denoted as WE ₁ , RE ₂ and WE _2. Each second wiring port is connected to a second relay, which are respectively denoted as B ₁ , B ₂ and B _3. WE ₁ is connected to one end of the electrode through a wire through B ₁ , WE ₂ is connected to the other electrode through a wire through B ₃ , and RE ₂ is connected to the shell through B ₂ through a wire.

6, the multi-partition resistance measurement module has 4 external interfaces, including 2 current interfaces and 2 voltage interfaces, the 2 current interfaces are respectively denoted as I ₊ and _I- ; the 2 voltage interfaces are respectively denoted as U ₊ and _U- . The current interface and the voltage interface are arranged at intervals from each other. Each external interface is respectively connected to a third relay, and the 4 third relays are respectively denoted as _G1 , _G2 , _G3 and _G4 .

There are multiple conductive contacts evenly distributed on the two electrodes, and the multiple conductive contacts divide the electrode surface into multiple partitions. In the embodiment of the present application, 17 partitions are set on each electrode as an example. There are 34 terminals evenly distributed on the two electrodes, including 17 current terminals and 17 voltage terminals, and the current terminals and voltage terminals are arranged at intervals. The 17 current terminals on one electrode are respectively recorded as C _1-17 , and the 17 voltage terminals are respectively recorded as D _1-17 . The current terminals C _1-17 are connected in parallel through G1 and I ₊ , and the voltage terminals D _1-17 are connected in parallel through G ₂ and U ₊ ; the 17 current terminals on the other electrode are respectively recorded as E1-17, and the 17 voltage terminals are respectively recorded as F1-17. The current terminals E1-17 are connected in parallel through G4 and I-, and the voltage terminals F _1-17 are connected in parallel through G ₃ and U _- .

Example 2

7 , a method for testing water seepage inside a coating using the measuring device disclosed in Example 1 of the present application includes the following steps:

S1: fix the measuring device at the position to be detected, close the first relay A _1-3 , measure the impedance of the sensor at different frequencies through the electrochemical impedance spectroscopy measurement module EIS, and draw an impedance spectrum;

S2: The imaginary part (-Z _Im ) of the electrochemical impedance spectrum of the complete coating system is calculated as follows:

Where f is the input signal frequency, R _c is the coating resistance, and C _c is the coating capacitance. When the test frequency f is high enough, the following formula can be simplified:

Since the dielectric constant of the coating changes as water penetrates into it, the water permeability between the two electrodes at time t can be calculated as follows:

In the formula, _εt is the dielectric constant at time t, _εm is the dielectric constant of the organic polymer of the coating, _εw is the dielectric constant of water, _φs represents the water permeability of the coating under saturation state, and _φt represents the permeability of the water coating at time t.

The coating capacitance can be expressed as:

The water permeability is expressed as: Where _Ct is the coating capacitance measured at time t, and _C0 is the coating capacitance at the initial time.

Example 3

8 , a method for testing the degree of damage of a coating based on the measuring device disclosed in Example 1 of the present application comprises the following steps:

S1: Fix the measuring device at the position to be detected, close the second relay _B1-3 , control the electrochemical noise module EN to measure, monitor the current noise signal between the two electrodes _WE1 and _WE2 , and monitor the potential noise signal between _WE1 and the housing.

S2: Use the third-order polynomial fitting method to eliminate the DC offset of the noise signal;

S3: Based on the processed data, the variance of the potential and current is calculated;

Where m is the total number of data points, Vi _{and Ii} are the voltage and current values of the ith data point, and is the average value of voltage and current

S4: The stability of the coating surface state is determined by the variance of potential and current, and the tendency of coating damage is evaluated.

Example 4

9 , a method for testing the metal corrosion rate of a coating based on the measuring device disclosed in Example 1 of the present application comprises the following steps:

S1: Fix the measuring device at the position to be tested, measure the surface temperature data of the sensor through the temperature measuring element, and obtain the change curve of the resistivity of the metal resistor to be tested with temperature;

S2: close the third relay G _1-4 , measure the local resistance change of the subareas 1-17 on the electrode by closing C _1-17 and D _1-17 in sequence, and record the temperature T ₀ during the measurement;

Then, the local resistance change of the subarea 1-17 on the electrode of the other electrode is measured by closing E _1-17 and F _1-17 in sequence, and the temperature T ₀ during the measurement is recorded;

Taking Zone 1 R _C1D1 as an example, the following formula is used for calculation:

Where a is the cross-sectional width, d is the cross-sectional height, and L is the spacing between C ₁ and D ₁ ;

For the nth measured resistance,

According to the actual temperature _Tn obtained by the temperature probe and the resistance-temperature curve, the resistance is corrected to the resistance at _T0 :

Where k is the resistivity variation coefficient at time T _n relative to time T ₀ ;

Analyze the data of the resistance measurement module, and calculate the metal corrosion rate of each partition in combination with the temperature measurement result of step S1;

The corrosion depth is: Δd _C1D1,n = d _C1D1,0 - d _C1D1,n ;

The corrosion rate is expressed as (△t is the measurement period):

Example 5

10 , a method for measuring the degree of coating damage and the metal corrosion rate at the damaged part based on the measuring device disclosed in Example 1 of the present application comprises the following steps:

S1: Fix the measuring device at the position to be tested;

S2: disconnect the temperature probe in the on state, turn on the first relay A _1-3 , control the electrochemical impedance spectroscopy measurement module EIS to measure and analyze the obtained data, and analyze the water seepage inside the coating by calculating the capacitance between the two electrodes;

S3: disconnect the first relay A _1-3 , open the second relay B _1-3 , control the electrochemical noise module EN to measure and analyze the acquired data, analyze the current noise signal between the two electrodes and the potential noise signal between the electrode and the shell to obtain the damage degree information of the electrode surface coating;

S4: disconnect the first relay A _1-3 and the second relay B _1-3 , turn on the temperature probe, and measure the sensor surface temperature data through the temperature measuring element;

S5: After measuring the temperature data, close the third relay G _1-4 , and measure the local resistance change of the subareas 1-17 on the electrode by closing C _1-17 and D _1-17 in sequence;

Then, disconnect C _1-17 and D _1-17 , and close E _1-17 and F _1-17 in sequence to measure the local resistance change of the subarea 1-17 on the electrode of the other electrode;

Finally, the ER data is analyzed and combined with the temperature measurement results to obtain the local corrosion rate of the metal.

In summary, the present invention uses an electrochemical impedance spectroscopy measurement module to evaluate the water seepage inside the coating, and combines the electrochemical noise module to collect the coating damage information on the electrode surface, so as to realize the estimation of the coating damage risk. At the same time, a temperature measurement module and a multi-partition resistance measurement module are used to correct the electrode partition resistance based on the temperature measurement data, so as to calculate the metal corrosion rate at the damaged coating. Through the combination of the two, the present invention can not only realize the coating damage status monitoring, but also anticipate the damage risk faced by the coating in advance.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims (6)

1. A measuring device for monitoring the degree of coating damage and the corrosion rate of the damaged part, characterized in that it comprises a waterproof sealed chamber with a cavity, a sensor, an electrochemical detection system and a fixing glue, the sensor comprises a shell capable of conducting electricity, two electrodes, a temperature measuring element and a filling glue, the shell has a cavity with an opening on one side, the two electrodes are evenly distributed at the opening of the shell and do not contact the shell, the opening end of the shell faces the coating to be measured, and the surface of the electrode contacts the surface of the coating to be measured; The temperature measuring element can monitor the temperature change of the electrode in real time. The temperature measuring element is arranged on the side of the electrode facing away from the coating. The temperature measuring element and the electrode are insulated. The filling glue can fix the electrode and the temperature measuring element inside the shell. The electrode comprises a plurality of parallel and spaced horizontal segments, wherein a return segment is disposed between adjacent horizontal segments, adjacent horizontal segments are disposed on the same side of the return segment, and adjacent return segments are disposed on opposite sides of the horizontal segment, and the interval between adjacent return segments is equal to the length of the corresponding horizontal segment; The two electrodes and the bottom of the shell are respectively connected with wires, and the two ends of the two electrodes are respectively provided with wires. The two electrodes are connected in series. After the series connection, the wires of the electrodes and the wires of the shell are respectively extended to the inside of the waterproof sealed chamber and connected to the electrochemical detection system inside the waterproof sealed chamber. The distance between adjacent electrodes is equal to the distance between the end of the electrode and the inner wall of the shell, and the distance between adjacent electrodes does not exceed 0.5mm. A thermal conductive silicone pad is provided between the temperature measuring element and the electrode; The sensor is fixedly mounted on the outside of the waterproof sealed chamber, the electrochemical detection system is fixedly mounted on the inside of the waterproof sealed chamber by means of fixing glue, and the sensor and the electrochemical detection system are electrically connected by means of a cable; The electrochemical detection system comprises an electrochemical impedance spectrum measurement module, an electrochemical noise module and a multi-partition resistance measurement module, which are connected in parallel and electrically connected to a sensor. 2. The measuring device for monitoring the degree of coating damage and the corrosion rate at the damaged part according to claim 1 is characterized in that a fixed hanging ear is fixedly provided on the outside of the waterproof sealed chamber, and the fixed hanging ear can fix the measuring device at the position to be detected. 3. The measuring device for monitoring the degree of coating damage and the corrosion rate at the damaged part according to claim 1, characterized in that the electrochemical impedance spectroscopy measurement module has three first wiring ports, each of which is connected to a first relay, and the electrochemical impedance spectroscopy measurement module is connected to the sensor through the first relay; The electrochemical noise module has three second wiring ports, each of which is connected to a second relay, and the electrochemical noise module is connected to the sensor via the second relay; The multi-partition resistance measurement module has four external interfaces, including two current interfaces and two voltage interfaces, each of the external interfaces is respectively connected to a third relay, and the multi-partition resistance measurement module is connected to the sensor via the third relay. 4. The measuring device for monitoring the degree of coating damage and the corrosion rate of the damaged part according to claim 3, characterized in that a plurality of current binding posts and a plurality of voltage binding posts are arranged between the third relay and the electrode, and the current binding posts and the voltage binding posts are arranged at intervals from each other; A plurality of conductive contacts are evenly distributed on the electrode, and any conductive contact is connected to the current terminal and/or the voltage terminal. The plurality of conductive contacts divide the electrode surface into a plurality of partitions. 5. A testing method based on the measuring device according to any one of claims 1 to 4, characterized in that it comprises the following steps: Close the electrochemical impedance spectroscopy measurement module, control the electrochemical impedance spectroscopy measurement module to perform measurement, and analyze the acquired data, and analyze the water seepage inside the coating by calculating the capacitance between the two electrodes; Or close the electrochemical noise module, control the electrochemical noise module to measure, and analyze the obtained data, analyze the current noise signal between the two electrodes and the potential noise signal between the electrode and the shell to obtain the damage degree information of the electrode surface coating. 6. A testing method based on the measuring device according to any one of claims 1 to 4, characterized in that it comprises the following steps: S1: Fix the measuring device at the position to be detected and measure the surface temperature data of the sensor through the temperature measuring element; S2: Close the multi-partition resistance measurement module to measure the local resistance changes of the two electrodes respectively; analyze the data of the resistance measurement module, and calculate the metal corrosion rate of each partition in combination with the temperature measurement result of step S1.