Movable combined probe for measuring coating debonding based on electroacoustic pulse principle

Abstract

The invention discloses a movable combined probe for measuring coating debonding based on an electroacoustic pulse principle, and relates to the technical field of nondestructive testing, the movable combined probe comprises a voltage pulse applying assembly and a probe detection assembly; the voltage pulse applying assembly comprises a first shielding shell, the first shielding shell is provided with two separated shielding grooves, a voltage applying device and a pulse applying device are arranged in the two shielding grooves respectively, and direct-current high voltage output by the voltage applying device and narrow pulse output by the pulse applying device can be superposed and applied to the metal substrate through the output end; the probe detection assembly comprises a second shielding shell and a detection electrode, a detection element is arranged in the second shielding shell, and the detection electrode is arranged on one side of the second shielding shell and makes contact with the coating on the metal substrate; the detection element is electrically connected with the detection electrode and detects a stress pulse signal on the detection electrode. According to the movable combined probe for measuring the coating debonding based on the electroacoustic pulse principle, provided by the invention, the adaptability and the accuracy of coating debonding detection are improved.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing technology, and in particular to a movable combined probe for measuring coating debonding based on the principle of electroacoustic pulses. Background Technology

[0002] To improve the performance of metals, coatings are often applied to their surfaces. For example, coating the inside of a metal pot creates a non-stick surface for easier cooking; coating the inner walls of piston cylinders in a fuel engine improves the wear and corrosion resistance of the metal, extending engine life. However, coating debonding can occur during the coating process. Due to technical issues with the coating material itself or metal surface treatment, quality problems may arise after coating application (or high-temperature sintering), such as poor or non-bonding of the coating to the substrate (metal). These issues will lead to quality problems during future use, and failure to detect them promptly will affect product quality. Therefore, effective testing methods are essential to detect debonding before the product leaves the factory; otherwise, weakly bonded areas will gradually detach after a period of use, resulting in further losses.

[0003] Commonly used coating debonding detection techniques mainly fall into two categories: ultrasonic testing and infrared thermography. While ultrasonic testing can be further subdivided into several different types of ultrasonic waves (essentially stress waves) based on their wave characteristics, it essentially involves externally inputting ultrasonic waves and then judging the presence of debonding based on the phase change of the reflected wave at the debonding point. However, the waveform itself is difficult to directly reflect the nature of the debonding area. Theoretically, the amplitude of the reflected wave can also reflect the presence of debonding, but because the coating is very thin and the waveform of the externally input wave is difficult to make consistent, it is difficult to identify debonding through amplitude changes. Infrared thermography, on the other hand, uses external excitation to change the temperature of the object under test, judging the presence of debonding based on differences in thermal imaging or phase differences; this method is generally not suitable for detecting large objects. Summary of the Invention

[0004] The purpose of this invention is to provide a movable combined probe for measuring coating debonding based on the principle of electroacoustic pulses, so as to solve the problems existing in the prior art and improve the adaptability and accuracy of coating debonding detection.

[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides a movable combined probe for measuring coating debonding based on the principle of electroacoustic pulses, comprising a voltage pulse application component and a probe detection component. The voltage pulse application component includes a first shielding shell with two separated shielding slots, in which a voltage application device and a pulse application device are respectively arranged. The first shielding shell has an output terminal for electrical connection with a metal substrate. The output terminal is electrically connected to both the voltage application device and the pulse application device. The high DC voltage output by the voltage application device and the narrow pulse output by the pulse application device can be superimposed and applied to the metal substrate through the output terminal. The probe detection component includes a second shielding shell and a detection electrode. A detection element is disposed within the second shielding shell, and the detection electrode is disposed on one side of the second shielding shell for contacting the coating on the metal substrate. The detection element is electrically connected to the detection electrode and is capable of detecting stress pulse signals on the detection electrode.

[0006] Preferably, a wire hole is provided between the two shielding slots, and the output terminal is connected to the shielding slot where the voltage applying device is located. The voltage applying device and the pulse applying device can be connected in the shielding slot where the voltage applying device is located, so that the DC high voltage and the narrow pulse can be superimposed.

[0007] Preferably, the voltage applying device includes a high-voltage resistor, and the shielding slot where the voltage applying device is located is provided with a high-voltage input terminal for electrically connecting to a high-voltage power supply. The two ends of the high-voltage resistor are respectively electrically connected to the high-voltage input terminal and the output terminal.

[0008] Preferably, the pulse application device includes a high-voltage capacitor, and the shielding slot where the pulse application device is located is provided with a pulse input terminal for electrically connecting a narrow pulse generator. The two ends of the high-voltage capacitor are respectively electrically connected to the pulse input terminal and the output terminal.

[0009] Preferably, the detection element includes a piezoelectric thin film sensor, which is disposed on the side of the detection electrode facing away from the coating and is capable of detecting stress pulse signals on the detection electrode.

[0010] Preferably, the detection element further includes a signal amplifier, which is communicatively connected to the piezoelectric thin film sensor. The signal amplifier is also communicatively connected to a signal analysis device, and the stress pulse signal detected by the detection element can be transmitted to the signal analysis device through the signal amplifier.

[0011] Preferably, the second shielding shell is provided with an outlet hole that connects the inside and outside, and the signal amplifier and the signal analysis device are communicatively connected through a transmission line passing through the outlet hole.

[0012] Preferably, the second shielding shell is divided into two shielding cavities from top to bottom by a partition plate. The signal amplifier is disposed in the upper shielding cavity, and the detection element is disposed in the lower shielding cavity. The outgoing hole connects the upper shielding cavity to the outside. The partition plate is provided with a lead hole connecting the upper and lower shielding cavities. The signal amplifier and the detection element are communicatively connected through a transmission line passing through the lead hole.

[0013] Preferably, the probe detection assembly further includes an absorbing element disposed on the side of the detection element opposite to the detection electrode.

[0014] Preferably, the detection electrode is used to fit and contact the coating surface and matches the shape of the coating.

[0015] The present invention achieves the following technical effects compared to the prior art: This invention provides a movable combined probe for measuring coating debonding based on the principle of electroacoustic pulses. The voltage pulse application component and the probe detection component are set up independently to avoid mutual interference and improve usability. By moving the probe detection component, debonding areas can be detected at any location on the coating, and even the edges of the debonding area can be detected. Furthermore, the voltage application device and pulse application device of the voltage pulse application component are arranged in two separate shielded slots, which avoids interference between the voltage input and the narrow pulse input, and also avoids external electromagnetic interference. Similarly, the probe detection component avoids external electromagnetic interference by placing the detection element in a second shielded shell. An external high DC voltage and an external narrow pulse are superimposed and applied to the metal substrate. When the detection electrode contacts the coating (coupling agent is placed between the detection electrode and the coating to ensure effective stress wave conduction), an electric field is formed between the detection electrode and the metal substrate. The coating (which is an insulating material) in the electric field will become polarized. Equal numbers of polarized charges with opposite signs will appear on both surfaces of the coating. That is, the side of the coating in contact with the metal substrate has polarized charges, and the other side of the coating (in contact with the detection electrode) has charges with opposite signs. When the amplitude of the applied DC high voltage changes suddenly under the action of a narrow pulse, the polarized charges on the upper and lower surfaces of the coating will vibrate suddenly and cause stress waves. If there is no debonding between the coating and the metal substrate, the electric field strength at the interface between the metal substrate and the coating is very large, or in other words, the polarized charges on the coating surface are subjected to a strong electric field force, which is equivalent to a kind of constraint. When the applied voltage changes suddenly, the vibration amplitude of the charges is low, and the stress pulse wave will also be transmitted into the coating, causing some of the wave energy to disappear in the metal substrate. These two reasons cause the amplitude of the stress pulse entering the electrode to be significantly smaller. By comparing the difference in amplitude between the two waves with and without debonding, the existence of debonding can be determined. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a connection diagram of a movable combined probe for measuring coating debonding based on the principle of electroacoustic pulses, provided in Embodiment 1 of the present invention. Figure 2 This is a schematic diagram of the interior of the first shielding shell provided in Embodiment 1 of the present invention; Figure 3 This is an internal schematic diagram of the voltage pulse application component provided in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the internal structure of the probe detection assembly provided in Embodiment 1 of the present invention; Figure 5 This is a stress pulse curve detected by a movable combined probe based on the electroacoustic pulse principle for measuring coating debonding, as provided in Embodiment 1 of the present invention.

[0018] In the figure: 1-Voltage pulse application component; 11-First shielding shell; 12-Shielding groove; 13-Voltage application device; 14-Pulse application device; 15-Wire passage hole; 16-High voltage input terminal; 17-Pulse input terminal; 18-Output terminal; 2-Metal substrate; 3-Probe detection component; 31-Second shielding shell; 32-Detection electrode; 33-Detection element; 34-Signal amplifier; 35-Outlet hole; 36-Shielding cavity; 37-Separator plate; 38-Lead hole; 39-Absorbing component; 4-Coating. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The purpose of this invention is to provide a movable combined probe for measuring coating debonding based on the principle of electroacoustic pulses, so as to solve the problems existing in the prior art and improve the adaptability and accuracy of coating debonding detection.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1 This embodiment provides a movable combined probe for measuring coating debonding based on the principle of electroacoustic pulses. Please refer to [link to relevant documentation]. Figures 1-5 The device includes a voltage pulse application assembly 1 and a probe detection assembly 3. The voltage pulse application assembly 1 includes a first shielding shell 11, which has two separated shielding slots 12. A voltage application device 13 and a pulse application device 14 are respectively arranged in the two shielding slots 12. The first shielding shell 11 has an output terminal 18 for electrical connection with a metal substrate 2. The output terminal 18 is electrically connected to both the voltage application device 13 and the pulse application device 14. The DC high voltage output by the voltage application device 13 and the narrow pulse output by the pulse application device 14 can be superimposed and applied to the metal substrate 2 through the output terminal 18. The probe detection assembly 3 includes a second shielding shell 31 and a detection electrode 32. A detection element 33 is disposed in the second shielding shell 31. The detection electrode 32 is disposed on one side of the second shielding shell 31 and is used to contact the coating 4 on the metal substrate 2. The detection element 33 is electrically connected to the detection electrode 32 and can detect the stress pulse signal on the detection electrode 32.

[0023] The voltage pulse application component 1 and the probe detection component 3 are set up independently to avoid mutual interference and improve the flexibility of use. By moving the probe detection component 3, the debonding part at any position on the coating 4 can be detected, and the edge of the debonding area can also be detected. In addition, the voltage application device 13 and the pulse application device 14 of the voltage pulse application component 1 are respectively arranged in two separate shielding slots 12, which can avoid interference between voltage input and narrow pulse input, and at the same time avoid external electromagnetic interference. Similarly, the probe detection component 3 avoids external electromagnetic interference by setting the detection element 33 in the second shielding shell 31. The applied DC high voltage and the applied narrow pulse are superimposed and connected to the metal substrate 2. When the detection electrode 32 contacts the coating 4 (some coupling agent is placed between the detection electrode 32 and the coating 4 to ensure effective transmission of stress wave), an electric field is formed between the detection electrode 32 and the metal substrate 2. The coating 4 in the electric field (which is an insulating layer) The insulating material will become polarized, and equal numbers of polarized charges with opposite signs will appear on both surfaces of the coating 4. That is, the side of the coating 4 in contact with the metal substrate 2 has polarized charges, and the other side of the coating 4 (in contact with the detection electrode 32) has charges with opposite signs. When the amplitude of the applied DC high voltage changes suddenly under the action of a narrow pulse, the polarized charges on the upper and lower surfaces of the coating 4 will vibrate suddenly and cause stress waves. If there is no debonding between the coating 4 and the metal substrate 2, the electric field strength at the interface between the metal substrate 2 and the coating 4 is very large, or in other words, the polarized charges on the surface of the coating 4 are subjected to a strong electric field force, which is equivalent to a kind of constraint. When the applied voltage changes suddenly, the vibration amplitude of the charges is low, and the stress pulse wave will also be transmitted into the coating 4, causing some of the wave energy to disappear in the metal substrate 2. These two reasons cause the amplitude of the stress pulse entering the detection electrode 32 to be significantly smaller. By comparing the difference in amplitude between the two waves with and without debonding, the existence of debonding can be determined.

[0024] In a further preferred embodiment, the first shielding shell 11 can be made of aluminum alloy, and the second shielding shell 31 can also be made of aluminum alloy. The material and size of the detection electrode 32 are related to the measurement sensitivity and accuracy. If the wave impedance (also known as acoustic impedance, which is equal to the product of material density and wave velocity) of the detection electrode 32 material is consistent with the wave impedance of the coating 4, stress waves are most easily transmitted to the detection electrode 32, resulting in high measurement sensitivity. Therefore, in practical applications, selecting the appropriate detection electrode 32 material according to different coating materials 4 is beneficial for measurement. In addition, making the detection electrode 32 and the second shielding shell 31 into one piece is beneficial for electromagnetic shielding. The detection electrode 32 and the second shielding shell 31 are made of the same material, and the appropriate material can be selected according to different coating materials 4.

[0025] Furthermore, in order to facilitate the installation of the internal components of the first shielding shell 11 and the second shielding shell 31, the first shielding shell 11 and the second shielding shell 31 can be configured to be detachable, such as including a shell and a cover, with the shell and the cover connected by snaps or bolts.

[0026] In the optional scheme of this embodiment, more preferably, a wire hole 15 is provided between the two shielding slots 12, and the output terminal 18 is connected to the shielding slot 12 where the voltage applying device 13 is located. The voltage applying device 13 and the pulse applying device 14 can be connected in the shielding slot 12 where the voltage applying device 13 is located, so that the DC high voltage and the narrow pulse can be superimposed.

[0027] By setting the through hole 15, the voltage application device 13 and the pulse application device 14 can be connected through the transmission line to realize the superposition of DC high voltage and narrow pulse, so as to carry out subsequent coating debonding detection.

[0028] In the optional embodiment, more preferably, the voltage applying device 13 includes a high-voltage resistor, and the shielding slot 12 where the voltage applying device 13 is located is provided with a high-voltage input terminal 16 for electrically connecting to a high-voltage power supply. The two ends of the high-voltage resistor are respectively electrically connected to the high-voltage input terminal 16 and the output terminal 18.

[0029] The high-voltage power supply inputs DC high voltage through a high-voltage resistor. Both the high-voltage input terminal 16 and the output terminal 18 can be configured as plug-in terminals such as sockets for easy electrical connection.

[0030] In the optional embodiment, more preferably, the pulse application device 14 includes a high-voltage capacitor, and the shielding slot 12 where the pulse application device 14 is located is provided with a pulse input terminal 17 for electrically connecting the narrow pulse generator. The two ends of the high-voltage capacitor are electrically connected to the pulse input terminal 17 and the output terminal 18, respectively.

[0031] The narrow pulse generator uses a high-voltage capacitor to input narrow pulses, and the pulse input terminal 17 is configured as a plug-in terminal such as a socket for easy electrical connection.

[0032] In an optional embodiment, more preferably, the detection element 33 includes a piezoelectric thin film sensor, which is disposed on the side of the detection electrode 32 facing away from the coating 4 and is capable of detecting stress pulse signals on the detection electrode 32.

[0033] The PVDF piezoelectric film sensor can convert stress wave signals into electrical signals for subsequent computer recording or input to a digital oscilloscope for display and recording of waveforms. Coupling agent should be placed between the detection electrode 32 and the PVDF piezoelectric film sensor to ensure effective transmission of stress waves.

[0034] In an optional embodiment, more preferably, the detection element 33 further includes a signal amplifier 34, which is communicatively connected to the piezoelectric thin film sensor. The signal amplifier 34 is also communicatively connected to a signal analysis device, and the stress pulse signal detected by the detection element 33 can be transmitted to the signal analysis device through the signal amplifier 34.

[0035] The PVDF piezoelectric film sensor converts the stress wave signal into an electrical signal, which is then input to a signal amplifier 34, such as a broadband voltage amplifier. The amplified signal is used as a measurement output and can be recorded by a computer or input to a digital oscilloscope for display and waveform recording.

[0036] In the optional scheme of this embodiment, more preferably, the second shielding shell 31 is provided with a cable outlet 35 that connects the inside and outside, and the signal amplifier 34 and the signal analysis device are connected for communication through a transmission line passing through the cable outlet 35.

[0037] The amplified signal is connected to a signal analysis device via a lead wire passing through the output hole 35. The signal analysis device can be a computer or a digital oscilloscope.

[0038] In the optional embodiment, more preferably, the second shielding shell 31 is divided into two shielding cavities 36 from top to bottom by a partition plate 37. The signal amplifier 34 is disposed in the upper shielding cavity 36, and the detection element 33 is disposed in the lower shielding cavity 36. The wire outlet hole 35 connects the upper shielding cavity 36 to the outside. The partition plate 37 is provided with a lead hole 38 connecting the upper and lower shielding cavities 36. The signal amplifier 34 and the detection element 33 are connected by a transmission line passing through the lead hole 38.

[0039] The system consists of two separate shielded cavities 36 formed by a partition plate 37, which respectively house the signal amplifier 34 and the detection element 33, thus preventing mutual interference between them. The communication connection between the signal amplifier and the detection element 33 is achieved through a transmission line passing through the lead hole 38.

[0040] In an optional embodiment, more preferably, the probe detection assembly 3 further includes an absorbing element 39 disposed on the side of the detection element 33 away from the detection electrode 32.

[0041] The absorbing element 39 absorbs stress waves to prevent the stress waves from being reflected from the transmission detection element 33 and interfering with the output signal of the detection element 33. The material can be plexiglass. Specifically, the absorbing element 39 can be fixedly disposed between the partition plate 37 and the detection element 33.

[0042] In the optional embodiments of this example, more preferably, the detection electrode 32 is used to be in contact with the coating 4 and to match the shape of the coating 4.

[0043] Considering that the size and shape of the debonding area can vary, the size of the detection electrode 32 needs to be different. If the debonding area is small and the area of ​​the detection electrode 32 is large, the debonding may not be detected. If the debonding area is large and the area of ​​the detection electrode 32 is small, the debonding and boundary can be identified by moving the electrode, thus achieving large-area coating scanning measurement. When the area of ​​the detection electrode 32 is completely in the debonding area, the amplitude of the measured stress pulse is the highest. When the detection electrode 32 is moved, the amplitude of the measured signal will decrease when the detection electrode 32 is located in part of the debonding area. If it is completely moved out of the debonding area, the amplitude of the measured signal will be very small and the waveform will be different. If the detection surface of the detection electrode 32 is made into a curved surface, it can be used to measure the curved surface coating 4 with the same curvature.

[0044] The specific test method for measuring coating debonding using a movable combined probe based on the electroacoustic pulse principle provided in this embodiment is as follows: An applied high DC voltage and an applied narrow pulse are superimposed and applied to the metal substrate 2. The second shielding shell 31 and the detection electrode 32 share a common ground (a common voltage reference point) with the applied high voltage. When the amplitude of the applied high voltage changes suddenly under the action of the narrow pulse voltage, the polarization charges on the upper and lower surfaces of the coating 4 will vibrate suddenly, causing stress waves (also known as electroacoustic ultrasound). Because the narrow pulse is very narrow, about 20 nanoseconds, the stress wave formed is actually a stress pulse, and three typical pulses are generally received. The polarization charges on the surface of the coating 4 in contact with the detection electrode 32 and on the surface of the coating 4 that is detached will vibrate, thus generating stress pulses; an upward wave and a downward wave are emitted from the interface between the coating 4 and the detection electrode 32. The upward wave first reaches the PVDF piezoelectric thin film sensor on the upper surface of the detection electrode 32, that is, the... Figure 5 Pulse a in the stress wave. The descending wave reflects back when it reaches the debonded surface, travels back and forth within the thickness of coating 4, and becomes pulse c when it reaches the PVDF piezoelectric film sensor. Simultaneously, another stress pulse wave is generated on the debonded surface of coating 4. This is an upward wave formed by the vibration of opposite charges, and becomes pulse b when it reaches the PVDF piezoelectric film sensor. Pulse b is generated at the interface between coating 4 and the substrate, and this pulse is more reflective of defects and bonding quality. It should be noted that pulses a and c originate from the same location and have the same charge vibration. Therefore, if the upward wave is a tensile wave, the descending wave must be a compressive wave. After this wave reaches the defect or debonded surface and reflects, it becomes a tensile wave again, meaning that the measured pulses a and c have the same sign. If there is debonding between coating 4 and the metal substrate 2, three stress pulses with relatively high amplitudes can be measured. The time between two adjacent pulses represents the time it takes for the stress pulse to travel through coating 4. If the thickness of coating 4 is known, the wave velocity in coating 4 can be calculated.

[0045] The detection method provided in this embodiment is completely different from general ultrasonic testing methods. Ultrasonic methods identify debonding based on reflected waves (amplitude and phase, mainly phase). The reflection process involves coupling of longitudinal and transverse waves, and the wave components originally contain both longitudinal and transverse waves, making identification relatively difficult. The stress pulse wave provided in this embodiment only contains longitudinal waves, and there is basically no coupling during the transmission process; the waveform, amplitude, and wave velocity directly reflect the existence of debonding, the density of the coating, and the elastic modulus, etc.; it is not only easy to identify, but also contains physical information of multiple materials under test.

[0046] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A movable combined probe for measuring coating debonding based on the principle of electroacoustic pulses, characterized in that: include: The voltage pulse application assembly (1) includes a first shielding shell (11), which has two separated shielding slots (12). A voltage application device (13) and a pulse application device (14) are respectively arranged in the two shielding slots (12). The first shielding shell (11) has an output terminal (18) for electrical connection with a metal substrate (2). The output terminal (18) is electrically connected to both the voltage application device (13) and the pulse application device (14). The DC high voltage output by the voltage application device (13) and the narrow pulse output by the pulse application device (14) can be superimposed and applied to the metal substrate (2) through the output terminal (18). The probe detection assembly (3) includes a second shielding shell (31) and a detection electrode (32). A detection element (33) is disposed inside the second shielding shell (31). The detection electrode (32) is disposed on one side of the second shielding shell (31) and is used to contact the coating (4) on the metal substrate (2). The detection element (33) is electrically connected to the detection electrode (32) and is capable of detecting the stress pulse signal on the detection electrode (32).

2. The movable combined probe for measuring coating debonding based on the electroacoustic pulse principle according to claim 1, characterized in that: A wire hole (15) is provided between the two shielding slots (12), and the output terminal (18) is connected to the shielding slot (12) where the voltage applying device (13) is located. The voltage applying device (13) and the pulse applying device (14) can be connected in the shielding slot (12) where the voltage applying device (13) is located, so that the DC high voltage and the narrow pulse can be superimposed.

3. The movable combined probe for measuring coating debonding based on the electroacoustic pulse principle according to claim 1, characterized in that: The voltage applying device (13) includes a high voltage resistor. The shielding slot (12) where the voltage applying device (13) is located is provided with a high voltage input terminal (16) for electrically connecting to a high voltage power supply. The two ends of the high voltage resistor are electrically connected to the high voltage input terminal (16) and the output terminal (18), respectively.

4. The movable combined probe for measuring coating debonding based on the electroacoustic pulse principle according to claim 1, characterized in that: The pulse application device (14) includes a high voltage capacitor. The shielding slot (12) where the pulse application device (14) is located is provided with a pulse input terminal (17) for electrically connecting a narrow pulse generator. The two ends of the high voltage capacitor are electrically connected to the pulse input terminal (17) and the output terminal (18), respectively.

5. The movable combined probe for measuring coating debonding based on the electroacoustic pulse principle according to claim 1, characterized in that: The detection element (33) includes a piezoelectric thin film sensor, which is disposed on the detection electrode (32) on the side opposite to the coating (4) and is capable of detecting stress pulse signals on the detection electrode (32).

6. The movable combined probe for measuring coating debonding based on the electroacoustic pulse principle according to claim 5, characterized in that: The detection element (33) further includes a signal amplifier (34), which is communicatively connected to the piezoelectric thin film sensor. The signal amplifier (34) is also communicatively connected to a signal analysis device. The stress pulse signal detected by the detection element (33) can be transmitted to the signal analysis device through the signal amplifier (34).

7. The movable combined probe for measuring coating debonding based on the electroacoustic pulse principle according to claim 6, characterized in that: The second shielding shell (31) is provided with a cable outlet (35) that connects the inside and outside. The signal amplifier (34) and the signal analysis device are connected by a transmission line that passes through the cable outlet (35).

8. The movable combined probe for measuring coating debonding based on the electroacoustic pulse principle according to claim 7, characterized in that: The second shielding shell (31) is divided into two shielding cavities (36) from top to bottom by a partition plate (37). The signal amplifier (34) is located in the upper shielding cavity (36), and the detection element (33) is located in the lower shielding cavity (36). The outgoing wire hole (35) connects the upper shielding cavity (36) to the outside. The partition plate (37) is provided with a lead wire hole (38) connecting the upper and lower shielding cavities (36). The signal amplifier (34) and the detection element (33) are connected by a transmission line passing through the lead wire hole (38).

9. The movable combined probe for measuring coating debonding based on the electroacoustic pulse principle according to claim 8, characterized in that: The probe detection assembly (3) also includes an absorbing element (39) disposed on the side of the detection element (33) away from the detection electrode (32).

10. The movable combined probe for measuring coating debonding based on the electroacoustic pulse principle according to claim 1, characterized in that: The detection electrode (32) is used to fit and contact the surface of the coating (4) and match the shape of the coating (4).

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