A device and method for monitoring metal cavitation erosion process by electrochemical noise

Abstract

The present application relates to the field of cavitation corrosion electrochemical in-situ testing, and particularly relates to a device and method for monitoring metal cavitation corrosion process by using electrochemical noise, which mainly solves the problems that the incubation period of cavitation corrosion cannot be accurately measured and real-time change information in the development process of cavitation corrosion cannot be obtained in the prior art. The present application mainly comprises a three-electrode part, an ultrasonic cavitation part, an electrochemical noise monitoring part and a data analysis part. The three-electrode part comprises two same surface working electrodes and a reference electrode; the ultrasonic cavitation part mainly comprises a variable amplitude rod, a clamp, a double-layer electrolytic cell and a thermostat; the electrochemical noise monitoring part mainly comprises a fastening device, a flame-retardant soundproof foam, a Faraday cage and an electrochemical workstation; and the data analysis part mainly analyzes the electrochemical noise data in the cavitation corrosion process by means of a computer. The present application can realize continuous in-situ monitoring of metal materials under cavitation corrosion conditions, and can also identify the surface damage evolution process in different cavitation corrosion time according to the change of noise data.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical in-situ testing of cavitation erosion, and relates to an apparatus and method for monitoring the cavitation erosion process of metals using electrochemical noise. Background Technology

[0002] Cavitation erosion is widespread in flow-through components in industries such as water conservancy, power, shipbuilding, petroleum, and chemical engineering, often causing premature failure of turbines, propellers, pumps, and valves. Traditional cavitation erosion testing methods mainly rely on weight loss, morphology, and roughness to reflect the cavitation erosion evolution process of in-service materials. These traditional testing methods have drawbacks such as cumbersome operation, large measurement errors, and inability to provide real-time information reflecting the changes in the cavitation damage process. Furthermore, traditional testing methods cannot effectively distinguish the transition process before and after the cavitation erosion incubation period, making it difficult to accurately measure the cavitation erosion incubation period. The cavitation erosion incubation period is the initial stage of cavitation erosion and contains much important unit damage information. The length of the cavitation erosion incubation period is one of the important parameters for evaluating the cavitation erosion resistance of materials; materials with longer incubation periods often have better cavitation erosion resistance. Establishing a new in-situ monitoring method for the cavitation erosion incubation period is beneficial for achieving rapid and accurate measurement of the cavitation erosion incubation period, thus providing a reliable guarantee for improving material cavitation resistance evaluation standards and enabling rapid material selection for cavitation-eroded components. Given the limitations of traditional testing methods, namely the lack of means to monitor the cavitation incubation period in real time and in situ, Chinese Patent Application No. 2021115861889 discloses "An ultrasonic cavitation device for real-time monitoring of metal cavitation process using acoustic emission." This device can monitor the acoustic emission signal of the cavitation process in real time. However, this invention places the device at an angle, causing uneven bubble generation and uneven stress on the surface of the cavitated sample, resulting in poor consistency of test results. The method of this invention, utilizing electrochemical noise for real-time in-situ monitoring of the metal cavitation process, is applicable to commercially available cavitation devices that mainly use vertically placed amplitude transformers. Summary of the Invention

[0003] To address the problems in the prior art, the present invention aims to provide an apparatus and method for monitoring the cavitation process of metals using electrochemical noise, thereby solving the problems in the prior art that cannot accurately measure the cavitation incubation period and cannot obtain real-time change information during the cavitation development process.

[0004] The technical solution of this invention is:

[0005] An apparatus for monitoring the cavitation process of metals using electrochemical noise is disclosed. The apparatus includes an analytical testing workstation, a cavitation erosion device, and a temperature control device. The cavitation erosion device contains a fastening device and a double-layer electrolytic cell. The inner layer of the double-layer electrolytic cell contains a cavitation erosion solution, and the outer layer contains a coolant. A lifting platform is located below the electrolytic cell to adjust the distance between the ultrasonic amplitude transformer and the sample. The working electrode is encapsulated within the sample. An ultrasonic lifting device for fine-tuning the position of the amplitude transformer is mounted on the amplitude transformer and fixed above the cavitation erosion device. The amplitude transformer extends through the top of the cavitation erosion device into the cavitation erosion solution. A clamp is located below the end of the amplitude transformer to fix the sample. A wire is connected to the back of the working electrode and extends from the sample. A reference electrode is fixed by the fastening device and placed vertically in the cavitation erosion solution. The cavitation erosion device is surrounded by a Faraday cage. Four wires extend from the analytical testing workstation, connecting to the wires on the two working electrodes, the reference electrode, and the Faraday cage, respectively. The temperature control device is connected to the outer layer of the electrolytic cell via a coolant inlet pipe and a coolant outlet pipe.

[0006] The cavitation solution is a conductive corrosion solution.

[0007] The reference electrode is a saturated calomel electrode.

[0008] The fastening device includes a bracket with an iron ring and a tightening bolt. The iron ring is used to clamp the reference electrode, and the position of the reference electrode is adjusted by the tightening bolt and the bracket.

[0009] The inner wall of the cavitation equipment is adhered with flame-retardant and sound-insulating foam to reduce cavitation echo interference.

[0010] The Faraday cage is made of copper wire and is used to shield against external electromagnetic interference.

[0011] The analytical testing workstation includes a computer and an electrochemical workstation.

[0012] A method for monitoring the cavitation erosion process of metals using electrochemical noise includes the following steps:

[0013] (1) Two working electrodes with copper wires welded to their backs are encapsulated in the same epoxy resin to make a sample. The two electrodes are in the same plane in the sample.

[0014] (2) Place the sample on the fixture so that the sample surface is parallel to the end surface of the amplitude rod, and the fixture is 5-10 mm away from the end of the amplitude rod;

[0015] (3) Place the reference electrode on the fastening device, and make the end surface of the reference electrode as flat as possible with the sample surface;

[0016] (4) Start the constant temperature equipment and let the flowing cooling water it provides maintain the temperature of the cavitation environment;

[0017] (5) Electrochemical noise testing was performed using a three-electrode system. Before testing, cavitation erosion was used to remove impurities from the sample surface.

[0018] (6) Perform ultrasonic cavitation on the amplitude transformer using appropriate cavitation setting parameters;

[0019] (7) Collect the electrochemical noise of the sample to obtain the test noise;

[0020] (8) In the analysis and testing workstation, data processing is performed using data analysis software, appropriate noise reduction methods are selected, and the test noise is analyzed in the time domain and frequency domain.

[0021] In step (1), the two electrodes are encapsulated using a double epoxy encapsulation technology. First, the electrodes are encapsulated with molten epoxy powder, and then encapsulated with ordinary epoxy resin on their outer layer.

[0022] In step (4), the ambient temperature is 25±2℃.

[0023] In step (6), the cavitation setting parameters include output frequency, output power and interpeak amplitude. The output frequency is 20 kHz and the output amplitude is 60 μm. 10%-30% of the maximum output power is selected for noise cavitation.

[0024] In step (8), the noise reduction method is to use a filtering method to separate the noise signal and prevent DC noise interference by filtering out specific frequency bands in the test noise.

[0025] In the method, a metal material that is not easily corroded in cavitation solution is used as the working electrode to make the sample, and background noise is collected. The test noise is subtracted from the background noise in the analysis and testing workstation to obtain the corrosion noise signal of the material surface.

[0026] In the method, the metal material is platinum. When obtaining cavitation background noise, a platinum sheet that exhibits passivation characteristics is selected as the electrode, which effectively avoids the electrochemical noise caused by corrosion of other metal electrodes in solution.

[0027] The design principle of this invention is:

[0028] In-situ monitoring of cavitation processes requires improvements to existing ultrasonic cavitation devices. As mentioned in the background section, a device and method for real-time monitoring of cavitation based on electrochemical noise technology should be provided. To ensure that the two electrodes have a uniform surface condition, the ultrasonic cavitation amplitude transformer is placed vertically, and the two electrodes are encapsulated in the same epoxy resin to form a sample that is on the same plane. The sample is then placed on a clamp 5-10 mm away from the end of the amplitude transformer.

[0029] To achieve electrochemical noise testing, the following technical measures were adopted: fixing the reference electrode with a fastening device, connecting the electrode with a copper wire, connecting the ground wire to the Faraday cage, filling the inside of the cavitation equipment with flame-retardant sound insulation cotton to reduce cavitation noise echo, and installing a Faraday cage on the outside of the equipment to isolate external electromagnetic interference.

[0030] To achieve more accurate in-situ monitoring of cavitation erosion, reducing the intensity of cavitation erosion helps distinguish between background noise and test noise. Background noise signals are collected using platinum plates and separated using filtering methods. Specific frequency bands in the measurement signal are filtered out to cancel DC noise interference. Finally, the material evolution noise signal is obtained by subtracting the background noise from the test noise.

[0031] To maintain a stable ambient temperature, circulating cooling water is provided through a thermostat, and a double-layer electrolytic cell structure is used for rapid cooling.

[0032] The present invention has the following advantages and beneficial effects:

[0033] (1) This invention is based on an improvement of the existing ultrasonic cavitation machine, and is simple to operate and low in cost;

[0034] (2) This invention enables dynamic in-situ monitoring of cavitation erosion in various corrosive media;

[0035] (3) The external Faraday cage of the present invention effectively shields environmental noise and electromagnetic interference;

[0036] (4) The present invention uses a platinum sheet as a test sample to collect background noise, which does not react significantly with the corrosive medium;

[0037] (5) This invention uses a filtering method to separate background noise and uses wavelet analysis to process the original data to intuitively reflect the noise signal;

[0038] (6) This invention enables rapid and accurate measurement during the incubation period, providing an important guarantee for solving the problem of material selection in cavitation erosion;

[0039] (7) This invention promotes the application of electrochemical noise technology in the field of cavitation erosion;

[0040] (8) The device of the present invention can monitor cavitation in situ in real time. Attached Figure Description

[0041] Figure 1This is a schematic diagram of an electrochemical monitoring device, including: 1. Electrochemical workstation; 2. Lead wire I; 3. Lead wire II; 4. Lead wire III; 5. Lead wire IV; 6. Computer; 7. Faraday cage; 8. Amplitude transformer; 9. Ultrasonic lifting device; 10. Flame-retardant and sound-insulating foam; 11. Support with iron ring; 12. Tightening bolt; 13. Reference electrode; 14. Sample; 15. Clamp; 16. Double-layer electrolytic cell; 17. Lifting platform; 18. Coolant inlet pipe; 19. Coolant outlet pipe; 20. Thermostat;

[0042] Figure 2 This is a measured graph of dynamic electrochemical noise;

[0043] Figure 3 The graph is a result of wavelet analysis processing.

[0044] Figure 4 Image of the external appearance during the gestation period;

[0045] Figure 5 This is a measured graph of background noise. Detailed implementation method:

[0046] Example 1

[0047] like Figure 1As shown, a device for monitoring the cavitation process of metal using electrochemical noise is disclosed. The device includes an analytical testing workstation, a cavitation equipment, and a temperature control device. The cavitation equipment is equipped with a fastening device and a double-layer electrolytic cell 16. The inner layer of the double-layer electrolytic cell 16 contains a cavitation solution, and the outer layer contains a coolant. A lifting platform 17 is located below the double-layer electrolytic cell 16 to adjust the distance between the ultrasonic amplitude transformer 8 and the sample 14. An ultrasonic lifting device 9 for fine-tuning the position of the amplitude transformer 8 is mounted on the amplitude transformer 8. The amplitude transformer 8 extends through the top of the cavitation equipment into the cavitation solution. A clamp 15 is located below the end of the amplitude transformer 8 to fix the sample 14 containing electrodes. Wires are connected to the back of the electrodes and extend from the sample 14. The fastening device includes a bracket 11 with an iron ring and a tightening bolt 12. The iron ring is used to clamp the reference electrode, and the position of the reference electrode is adjusted by the tightening bolt 12 and the bracket. The reference electrode is fixed by the fastening device and placed vertically in the cavitation solution. The cavitation equipment is surrounded by a Faraday cage 7, which is made of copper wire and is used to shield against external electromagnetic interference. The inner wall of the cavitation equipment is adhered with flame-retardant and sound-insulating foam 10 to reduce cavitation echo interference. The analysis and testing workstation includes a computer 6 and an electrochemical workstation 1. The electrochemical workstation 1 is directly connected to the computer 6 on one side and connected to wires I2, II3, III4, and IV5 on the other side. Wires I2 and II3 are connected to the two electrodes in the sample 14, wire III4 is connected to the reference electrode 13, and wire IV5 is connected to the Faraday cage 7. The thermostat 20 is connected to the outer layer of the electrolytic cell through a coolant inlet pipe 18 and a coolant outlet pipe 19.

[0048] The cavitation solution is a conductive corrosion solution.

[0049] The reference electrode is a saturated calomel electrode.

[0050] Example 2

[0051] A method for monitoring the cavitation erosion process of metals using electrochemical noise includes the following steps:

[0052] (1) Two test electrodes with copper wires welded to their backs were encapsulated in the same epoxy resin to make a test sample. The two electrodes were on the same plane in the sample to ensure that the surfaces of the two electrodes were subjected to uniform cavitation erosion intensity. Platinum, which is not easily corroded in cavitation erosion solution, was used as the background electrode to make the background sample. The two electrodes in the sample were encapsulated with double epoxy technology. First, the electrodes were encapsulated with molten epoxy powder, and then encapsulated with ordinary epoxy resin on the outer layer. When obtaining the cavitation erosion background noise, a platinum sheet with passivation characteristics was selected as the electrode to effectively avoid the electrochemical noise generated by corrosion in solution when other metal electrodes were used.

[0053] (2) Place the background sample on the fixture, making the sample surface parallel to the end surface of the amplitude rod, and the fixture is 5mm away from the end of the amplitude rod;

[0054] (3) Place the reference electrode on the fastening device, and make the end surface of the reference electrode as flat as possible with the sample surface;

[0055] (4) Start the thermostat and let the flowing cooling water it provides maintain the cavitation environment temperature at 25±2℃;

[0056] (5) Electrochemical noise testing was performed using a three-electrode system. Before testing, cavitation erosion was used to remove impurities from the sample surface.

[0057] (6) Set the cavitation parameters: output frequency 20kHz, output amplitude 60μm, and select 30% of the maximum output power for noise cavitation.

[0058] (7) Background noise is collected using background samples;

[0059] (8) Collect the noise of the test sample according to the method of collecting the background sample to obtain the test noise;

[0060] (9) In the analysis and testing workstation, the material surface corrosion noise signal is obtained by subtracting the background noise from the test noise. The relevant data is processed by the data analysis software. The noise signal is separated by the filtering method. The interference of DC noise is prevented by filtering out specific frequency bands in the measurement signal. Correlation analysis is performed in the time domain and frequency domain.

[0061] like Figure 2 As shown, the measured dynamic electrochemical noise graph can be obtained by subtracting the background noise data from the measured test noise data. The graph shows numerous short-timescale transient peaks in both current and potential noise before 5236 s, while long-timescale transients appear after 5236 s. This indicates that before the incubation period, the sample surface is intact, and pitting corrosion is the dominant process. After the incubation period, material damage occurs, the passivation film cannot repair itself in time, and steady-state pitting corrosion signals appear.

[0062] like Figure 3 As shown in the figure, the electrochemical current noise map processed by wavelet analysis reveals that during the incubation period, the relative energy accumulation of the sample is mainly distributed in the d1-d3 region, and the sample surface is relatively intact, with the passivation film on the sample surface damaged by bubbles being able to repair itself in time. After the incubation period, the relative energy accumulation of the sample shifts to the d6-d8 region, and a large number of steady-state pitting corrosion signals appear. Wavelet analysis can intuitively reflect the changes before and after the incubation period.

[0063] Figure 4 As shown, the morphology of the test sample during and after the incubation period is shown. During the incubation period, the surface is mainly subjected to plastic deformation and no sample detachment occurs. After the incubation period, microcracks appear and material peeling occurs on the sample surface.

[0064] Figure 5 The transient amplitude of the electrochemical potential noise, which shows background noise, is small, and the current noise changes to white noise around DC, consistent with the passivation state signal of the platinum electrode in the corrosive solution.

[0065] Example 3

[0066] A method for monitoring the cavitation erosion process of metals using electrochemical noise includes the following steps:

[0067] (1) Two test electrodes with copper wires welded to their backs were encapsulated in the same epoxy resin to make a test sample. The two electrodes were on the same plane in the sample to ensure that the surfaces of the two electrodes were subjected to uniform cavitation erosion intensity. Platinum, which is not easily corroded in cavitation erosion solution, was used as the background electrode to make the background sample. The two electrodes in the sample were encapsulated with double epoxy technology. First, the electrodes were encapsulated with molten epoxy powder, and then encapsulated with ordinary epoxy resin on the outer layer. When obtaining the cavitation erosion background noise, a platinum sheet with passivation characteristics was selected as the electrode to effectively avoid the electrochemical noise generated by corrosion in solution when other metal electrodes were used.

[0068] (2) Place the background sample on the fixture, making the sample surface parallel to the end surface of the amplitude rod, and the fixture is 5mm away from the end of the amplitude rod;

[0069] (3) Place the reference electrode on the fastening device, and make the end surface of the reference electrode as flat as possible with the sample surface;

[0070] (4) Start the thermostat and let the flowing cooling water it provides maintain the cavitation environment temperature at 25±2℃;

[0071] (5) Electrochemical noise testing was performed using a three-electrode system. Before testing, cavitation erosion was used to remove impurities from the sample surface.

[0072] (6) Set the cavitation parameters: output frequency 20kHz, output amplitude 60μm, and select 15% of the maximum output power for noise cavitation.

[0073] (7) Background noise is collected using background samples;

[0074] (8) Collect the noise of the test sample according to the method of collecting the background sample to obtain the test noise;

[0075] (9) In the analysis and testing workstation, the material surface corrosion noise signal is obtained by subtracting the background noise from the test noise. The relevant data is processed by the data analysis software. The noise signal is separated by the filtering method. The interference of DC noise is prevented by filtering out specific frequency bands in the measurement signal. Correlation analysis is performed in the time domain and frequency domain.

[0076] Example 4

[0077] A method for monitoring the cavitation erosion process of metals using electrochemical noise includes the following steps:

[0078] (1) Two test electrodes with copper wires welded to their backs were encapsulated in the same epoxy resin to make a test sample. The two electrodes were on the same plane in the sample to ensure that the surfaces of the two electrodes were subjected to uniform cavitation erosion intensity. Platinum, which is not easily corroded in cavitation erosion solution, was used as the background electrode to make the background sample. The two electrodes in the sample were encapsulated with double epoxy technology. First, the electrodes were encapsulated with molten epoxy powder, and then encapsulated with ordinary epoxy resin on the outer layer. When obtaining the cavitation erosion background noise, a platinum sheet with passivation characteristics was selected as the electrode to effectively avoid the electrochemical noise generated by corrosion in solution when other metal electrodes were used.

[0079] (2) Place the background sample on the fixture, making the sample surface parallel to the end surface of the amplitude rod, and the fixture 7mm away from the end of the amplitude rod;

[0080] (3) Place the reference electrode on the fastening device, and make the end surface of the reference electrode as flat as possible with the sample surface;

[0081] (4) Start the thermostat and let the flowing cooling water it provides maintain the cavitation environment temperature at 25±2℃;

[0082] (5) Electrochemical noise testing was performed using a three-electrode system. Before testing, cavitation erosion was used to remove impurities from the sample surface.

[0083] (6) Set the cavitation parameters: output frequency 20kHz, output amplitude 60μm, and select 20% of the maximum output power for noise cavitation.

[0084] (7) Background noise is collected using background samples;

[0085] (8) Collect the noise of the test sample according to the method of collecting the background sample to obtain the test noise;

[0086] (9) In the analysis and testing workstation, the material surface corrosion noise signal is obtained by subtracting the background noise from the test noise. The relevant data is processed by the data analysis software. The noise signal is separated by the filtering method. The interference of DC noise is prevented by filtering out specific frequency bands in the measurement signal. Correlation analysis is performed in the time domain and frequency domain.

[0087] Example 5

[0088] A method for monitoring the cavitation erosion process of metals using electrochemical noise includes the following steps:

[0089] (1) Two test electrodes with copper wires welded to their backs were encapsulated in the same epoxy resin to make a test sample. The two electrodes were on the same plane in the sample to ensure that the surfaces of the two electrodes were subjected to uniform cavitation erosion intensity. Platinum, which is not easily corroded in cavitation erosion solution, was used as the background electrode to make the background sample. The two electrodes in the sample were encapsulated with double epoxy technology. First, the electrodes were encapsulated with molten epoxy powder, and then encapsulated with ordinary epoxy resin on the outer layer. When obtaining the cavitation erosion background noise, a platinum sheet with passivation characteristics was selected as the electrode to effectively avoid the electrochemical noise generated by corrosion in solution when other metal electrodes were used.

[0090] (2) Place the background sample on the fixture, making the sample surface parallel to the end surface of the amplitude rod, and the fixture 10mm away from the end of the amplitude rod;

[0091] (3) Place the reference electrode on the fastening device, and make the end surface of the reference electrode as flat as possible with the sample surface;

[0092] (4) Start the thermostat and let the flowing cooling water it provides maintain the cavitation environment temperature at 25±2℃;

[0093] (5) Electrochemical noise testing was performed using a three-electrode system. Before testing, cavitation erosion was used to remove impurities from the sample surface.

[0094] (6) Set the cavitation parameters: output frequency 20kHz, output amplitude 60μm, and select 25% of the maximum output power for noise cavitation.

[0095] (7) Background noise is collected using background samples;

[0096] (8) Collect the noise of the test sample according to the method of collecting the background sample to obtain the test noise;

[0097] (9) In the analysis and testing workstation, the material surface corrosion noise signal is obtained by subtracting the background noise from the test noise. The relevant data is processed by the data analysis software. The noise signal is separated by the filtering method. The interference of DC noise is prevented by filtering out specific frequency bands in the measurement signal. Correlation analysis is performed in the time domain and frequency domain.

[0098] Example 6

[0099] A method for monitoring the cavitation erosion process of metals using electrochemical noise includes the following steps:

[0100] (1) Two test electrodes with copper wires welded to their backs were encapsulated in the same epoxy resin to make a test sample. The two electrodes were on the same plane in the sample to ensure that the surfaces of the two electrodes were subjected to uniform cavitation erosion intensity. Platinum, which is not easily corroded in cavitation erosion solution, was used as the background electrode to make the background sample. The two electrodes in the sample were encapsulated with double epoxy technology. First, the electrodes were encapsulated with molten epoxy powder, and then encapsulated with ordinary epoxy resin on the outer layer. When obtaining the cavitation erosion background noise, a platinum sheet with passivation characteristics was selected as the electrode to effectively avoid the electrochemical noise generated by corrosion in solution when other metal electrodes were used.

[0101] (2) Place the background sample on the fixture, making the sample surface parallel to the end surface of the amplitude rod, and the fixture 10mm away from the end of the amplitude rod;

[0102] (3) Place the reference electrode on the fastening device, and make the end surface of the reference electrode as flat as possible with the sample surface;

[0103] (4) Start the thermostat and let the flowing cooling water it provides maintain the cavitation environment temperature at 25±2℃;

[0104] (5) Electrochemical noise testing was performed using a three-electrode system. Before testing, cavitation erosion was used to remove impurities from the sample surface.

[0105] (6) Set the cavitation parameters: output frequency 20kHz, output amplitude 60μm, and select 10% of the maximum output power for noise cavitation.

[0106] (7) Background noise is collected using background samples;

[0107] (8) Collect the noise of the test sample according to the method of collecting the background sample to obtain the test noise;

[0108] (9) In the analysis and testing workstation, the material surface corrosion noise signal is obtained by subtracting the background noise from the test noise. The relevant data is processed by the data analysis software. The noise signal is separated by the filtering method. The interference of DC noise is prevented by filtering out specific frequency bands in the measurement signal. Correlation analysis is performed in the time domain and frequency domain.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for monitoring the cavitation erosion process of metals using electrochemical noise, comprising the following steps: (1) Two working electrodes with copper wires welded to their backs are encapsulated in the same epoxy resin to make a sample. The two electrodes are in the same plane in the sample. (2) Place the sample on the fixture so that the sample surface is parallel to the end surface of the amplitude rod, and the fixture is 5-10 mm away from the end of the amplitude rod; (3) Place the reference electrode on the fastening device, with the end surface of the reference electrode flush with the sample surface; (4) Start the constant temperature equipment and let the flowing cooling water it provides maintain the temperature of the cavitation environment; (5) Electrochemical noise testing was performed using a three-electrode system. Before testing, cavitation erosion was used to remove impurities from the sample surface. (6) Perform ultrasonic cavitation on the parameters set for the amplitude transformer; (7) Collect the electrochemical noise of the sample to obtain the test noise; (8) In the analysis and testing workstation, data processing is performed by data analysis software, and noise signals are separated by filtering method. DC noise interference is prevented by filtering out a certain frequency band in the test noise. The test noise is analyzed in the time domain and frequency domain to realize the measurement of the cavitation incubation period of the sample. In step (2), the distance between the amplitude transformer and the sample is adjusted by the lifting platform and the ultrasonic lifting device; Samples were prepared using a metal material that is not easily corroded in cavitation solution as the working electrode, and background noise was collected. The background noise was subtracted from the test noise in the analysis and testing workstation to obtain the corrosion noise signal of the material surface. The method employs a device for monitoring the cavitation process of metals using electrochemical noise, comprising an analytical testing workstation, a cavitation equipment, and a temperature control device. The cavitation equipment includes a fastening device and a double-layer electrolytic cell. The inner layer of the double-layer electrolytic cell contains a cavitation solution, and the outer layer contains a coolant. A lifting platform is located below the electrolytic cell to adjust the distance between the ultrasonic amplitude transformer and the sample. The working electrode is encapsulated within the sample. An ultrasonic lifting device for fine-tuning the amplitude transformer's position is mounted on the amplitude transformer and fixed above the cavitation equipment. The amplitude transformer extends through the top of the cavitation equipment into the cavitation solution. A clamp is located below the end of the amplitude transformer to secure the sample. A wire is connected to the back of the working electrode and extends from the sample. A reference electrode is fixed by the fastening device and placed vertically in the cavitation solution. The cavitation equipment is surrounded by a Faraday cage. Four wires extend from the analytical testing workstation, connecting to the wires on the two working electrodes, the reference electrode, and the Faraday cage, respectively. The temperature control device is connected to the outer layer of the electrolytic cell via a coolant inlet pipe and a coolant outlet pipe. The fastening device includes a bracket with an iron ring and a tightening bolt. The iron ring is used to clamp the reference electrode, and the position of the reference electrode is adjusted by the tightening bolt and the bracket. Flame-retardant and sound-insulating foam is adhered to the inner wall of the cavitation equipment to reduce cavitation echo interference. The Faraday cage is made of copper wire and is used to shield against external electromagnetic interference.

2. The method for monitoring metal cavitation erosion process using electrochemical noise according to claim 1, characterized in that, The cavitation solution is a conductive corrosive solution, and the reference electrode is a saturated calomel electrode.

3. The method for monitoring metal cavitation erosion process using electrochemical noise according to claim 1, characterized in that, Analytical testing workstations include computers and electrochemical workstations.

4. The method for monitoring metal cavitation erosion process using electrochemical noise according to claim 1, characterized in that, In step (1), the two electrodes are encapsulated using a double epoxy encapsulation technology. First, the electrodes are encapsulated with molten epoxy powder, and then encapsulated with ordinary epoxy resin on their outer layer.

5. The method for monitoring metal cavitation erosion process using electrochemical noise according to claim 1, characterized in that, In step (4), the ambient temperature is 25±2℃.

6. The method for monitoring metal cavitation erosion process using electrochemical noise according to claim 1, characterized in that, In step (6), the parameters set include output frequency, output power and interpeak amplitude, with an output frequency of 20 kHz and an output amplitude of 60 μm.

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