Device for non-destructive detection of coating detachment on a component

Abstract

Device for non-destructive detection of coating detachment on a component, comprising: a high-voltage power source, a tension screw, a narrow pulse generator, a first electrode and a second electrode, a thin-film shield and a piezoelectric thin film arranged inside the thin-film shield; wherein the high-voltage power source is connected to the first electrode by means of a high-voltage resistor and is configured to apply a DC high voltage to the first electrode; The narrow pulse generator is connected to the first electrode via a high-voltage capacitor and is configured to apply a narrow pulse with a width smaller than a setpoint to the first electrode; the second electrode is connected to the high-voltage power source and a ground connection of the pulse generator, and the second electrode is a housing with one open side facing upwards; the thin-film shielding is arranged in the housing; a threaded hole suitable for the clamping screw is formed in a base surface of the housing; the clamping screw extends from the outside of the housing through the threaded hole in the base surface of the housing to support itself against the base surface of the thin-film shielding; the thin-film shield is made of an electrically conductive material and serves for electromagnetic shielding; wherein an outer side surface of an upper end of the thin-film shield abuts an insulating coating section of a detected component, while an inner side surface of the upper end of the thin-film shield abuts the piezoelectric thin film, wherein the thin-film shield is further connected to the second electrode; wherein the detected component comprises a body section and the insulating coating section; the piezoelectric thin film is configured to convert detected sound waves into an electrical voltage signal; wherein the voltage signal is analyzed to determine the delamination of the insulating coating of the detected component; and wherein If the detected component is a metal component, the first electrode is the body section of the metal component; whereas, if the detected component is a polymer component, the detection device further comprises: a metal plate serving as the first electrode and adjacent to the body section of the polymer component.

Description

TECHNICAL AREA

[0001] The present disclosure relates to the field of non-destructive detection and in particular to a device for non-destructively detecting the detachment of a coating on a component. BACKGROUND

[0002] Metals and polymers are frequently coated with a layer of ceramic or other insulating materials to improve their performance and properties (e.g., wear resistance, corrosion resistance, and high-temperature resistance) and expand their range of applications. However, coating delamination can severely impair the application of a metal or polymer component. When conventional ultrasonic detection is used to detect delamination, the coating is often so thin that weak detection signals and blind spots may exist on the surface, increasing the difficulty of detection. Therefore, there is a need for devices that can non-destructively detect the delamination of an insulating coating on a component.

[0003] These devices can be based on devices known for the detection of defects in general or for the detection of impurities. In this context, JP H06-258 380 A describes a device for the non-destructive examination of a defect or impurity in an insulator, for example, an insulator for power cables. CN 106 442 716 A1 discloses a method and a device for the detection of internal defects in a composite insulator. CN 110 058 093 A relates to a space charge detection system intended for the inspection of insulating materials. SUMMARY

[0004] The present disclosure aims to provide a device for the non-destructive detection of the delamination of an insulating coating on a component.

[0005] To solve the above problem, the present revelation provides the following solution: A device for non-destructive detection of coating delamination on a component includes: a high-voltage power source, a clamping screw, a narrow pulse generator, a first electrode and a second electrode, a thin-film shield, and a piezoelectric thin film arranged within the thin-film shield.

[0006] The high-voltage power source is connected to the first electrode via a high-voltage resistor and configured to apply a DC high voltage to the first electrode.

[0007] The narrow pulse generator is connected to the first electrode via a high-voltage capacitor and is configured to apply a narrow pulse with a width smaller than a setpoint to the first electrode.

[0008] The second electrode is connected to the high-voltage power source and a ground connection of the pulse generator, and the second electrode is a housing with one open side facing upwards.

[0009] The thin-film shield is arranged within the housing. A threaded hole corresponding to the clamping screw is formed in a base surface of the housing. The clamping screw extends from the outside of the housing through the threaded hole in the base surface to rest against the base surface of the thin-film shield. The thin-film shield is made of an electrically conductive material and serves for electromagnetic shielding. An outer side surface of the upper end of the thin-film shield abuts an insulating coating section of a detected component, while an inner side surface of the upper end of the thin-film shield abuts the piezoelectric thin film. The thin-film shield is also connected to the second electrode. The detected component comprises a body section and the insulating coating section.

[0010] The piezoelectric thin film is configured to convert detected ultrasonic waves (hereinafter also referred to as "stress waves") into a voltage signal (an electrical voltage signal); the voltage signal is analyzed to determine the delamination of the insulating coating of the detected component.

[0011] If the detected component is a metal component, the first electrode corresponds to the body section of the metal component; whereas, if the detected component is a polymer component, the detection device further includes: a metal plate that serves as the first electrode and is adjacent to the body section of the polymer component.

[0012] Alternatively, the detection device further comprises: a wave-absorbing block arranged within the thin-film shield. The wave-absorbing block borders the piezoelectric thin film.

[0013] Alternatively, the detection device further includes: a rubber pad arranged between an inner base surface of the thin-film shielding and the wave-absorbing block.

[0014] Alternatively, a positioning ring, formed integrally with the housing, is arranged on the inner side of the housing base. The thin-film shielding is located within the positioning ring, with a sealing pad positioned between the positioning ring and a side wall of the thin-film shielding.

[0015] Alternatively, the detection device also includes a rubber washer. The edge of the housing is hermetically sealed to the insulating coating section of the detected component by means of the rubber washer.

[0016] Alternatively, an inlet pipe and an outlet pipe are arranged on the housing, with the outlet pipe being connected to a vacuum pump.

[0017] Alternatively, the detection device also includes a signal amplifier. The piezoelectric thin film is connected to a signal analysis device via the signal amplifier.

[0018] Alternatively, the signal analysis device includes an oscilloscope and / or a computer.

[0019] According to specific embodiments provided in the present disclosure, the present disclosure has the following technical effects: The device for non-destructive detection of coating delamination on a component applies a high electric field and a narrow pulse signal to an insulating coating, based on the properties of the insulation and the ease of polarization of the insulating coating. Under the influence of the high electric field, polarization charges are generated on the delamination area of ​​the insulating coating. The polarization charges are excited by the narrow pulse signal to generate stress waves, which are detected to determine whether coating delamination is occurring. Consequently, non-destructive detection of insulating coating delamination on the component is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To more clearly describe the technical solutions in the embodiments of the present disclosure or in the prior art, the accompanying drawings necessary for describing the embodiments are briefly described below. Obviously, the accompanying drawings in the following description only show some embodiments of the present disclosure, but a person skilled in the art can nevertheless derive other drawings from these accompanying drawings without creative effort. Fig. Figure 1 is a schematic structure diagram of a device for non-destructive detection of the delamination of a coating on a metal component according to an embodiment of the present disclosure. Fig. Figure 2 is a schematic structure diagram of a device for non-destructively detecting the delamination of a coating on a polymer component according to an embodiment of the present disclosure. Fig. 3(a) is a schematic graphical representation of a component with a detachment defect in an insulating coating thereof according to an embodiment of the present disclosure, and Fig. 3(b) is a test curve graph of the component, as in Fig. 3(a) is shown.

[0021] The reference symbols denote the following: 1 High-voltage capacitor, 2 High-voltage resistor, 3 First electrode, 4 Second electrode, 5 Rubber washer, 6 Thin-film shielding, 7 Insulating coating section, 8 Piezoelectric thin film (PVDF layer), 9 Wave-absorbing block, 10 Rubber pad, 11 Sealing pad, 12 Tensioning screw, 13 Inlet valve, 14 Outlet valve, 15 Signal amplifier and 16 Positioning ring. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of this disclosure are described below clearly and completely with reference to the accompanying drawings in the embodiments of this disclosure. Obviously, the described embodiments represent only a part, rather than all, of the embodiments of this disclosure. All other embodiments that a person skilled in the art in the field could derive from the embodiments in this disclosure without creative effort shall fall within the scope of protection of this disclosure.

[0023] In order to make the above task, features and advantages of the present disclosure clearer and more understandable, the present disclosure is described in detail below with regard to the accompanying drawings and the specific embodiments.

[0024] The present disclosure provides a device for the non-destructive detection of coating delamination on a component. As described in Fig. As shown in Figure 1, the detection device comprises: a high-voltage power source, a narrow pulse generator, a first electrode 3, a second electrode 4, a thin-film shield 6, and a piezoelectric thin film 8 arranged within the thin-film shield 6. The detected component comprises a body section and an insulating coating section 7, which is formed on the surface of the body section by spraying. The high-voltage power source is connected to the first electrode 3 via a high-voltage resistor 2 and configured to apply a high voltage, which can exceed tens of thousands of volts, to the first electrode 3. The narrow pulse generator is connected to the first electrode 3 via a high-voltage capacitor 1 and configured to generate a narrow pulse (typically less than 50 nanoseconds, e.g., 1 / 3 of a second).The first electrode 3 is connected to the second electrode 3 for a duration of 10 nanoseconds with a width smaller than a setpoint. The second electrode 4 is connected to the high-voltage power source and a ground terminal of the pulse generator. The thin-film shield 6 is made of an electrically conductive material (e.g., aluminum); its inner and outer surfaces at one end (5–10 mm thick) are parallel, with the outer surface adjacent to the insulating coating on the surface of the detected component, while the inner surface adjacent to the piezoelectric thin film 8, which is used to receive a measurement signal. The thin-film shield 6 is further connected to the second electrode 4, thus enabling conduction between the thin-film shield 6 and the second electrode 4.The piezoelectric thin film 8 (polyvinylidene fluoride, PVDF layer) is configured to convert detected stress waves into an electrical voltage signal. The voltage signal is analyzed to determine whether delamination of the insulating coating on the detected component is occurring.

[0025] If the detected component is a metal component, as in Fig. As shown in Figure 1, the first electrode 3 is the body section of the metal component; whereas, if the detected component is a polymer component, as in Figure 1, the first electrode 3 is the body section of the metal component. Fig. As shown in Figure 2, the detection device further comprises: a metal plate which serves as the first electrode 3 and is adjacent to the body section of the polymer component. The metal plate can be temporarily attached to the polymer element by temporary gluing or holding.

[0026] In this embodiment, the insulating coating of the detected component can be polarized under the influence of an external electric field, whereby the density of the polarizing charges on the surface of an internal defect may be higher than in another region. A narrow-width pulse (e.g., 10 nanoseconds) is used to cause a brief, sudden change in the external electric field, causing the charges of the insulating coating to oscillate and form a series of stress waves (which are mainly longitudinal waves). The amplitude of the waves is greater at a location where the charge density is higher. If the corresponding stress waves are detected by the piezoelectric thin film 8, this indicates that the insulating coating of the detected component has a delamination defect.

[0027] In this embodiment, the detection device can further include: a wave-absorbing block 9 arranged within the thin-film shield 6. The wave-absorbing block 9 is adjacent to the piezoelectric thin film 8. The wave-absorbing block 9 serves to absorb sound waves in order to prevent a reflected signal from interfering with an output signal and can be made of organic glass.

[0028] In this embodiment, the detection device can further include: a rubber pad 10 arranged between an inner base surface of the thin-film shield 6 and the wave-absorbing block 9. The degree of compression of the wave-absorbing block 9 on the piezoelectric thin film 8 is adjusted by changing the thickness of the rubber pad 10 to prevent the defect in the detected component from closing due to excessive pressure. The positive and negative charges induced by the external electric field are neutralized, whereas insufficient pressure prevents the detected component from making firm contact with the electrode, which is detrimental to the transmission of voltage waves.

[0029] In this embodiment, the detection device may further include a clamping screw 12. The second electrode 4 is a housing with an open side facing upwards.

[0030] The thin-film shield 6 is arranged within the housing. A threaded hole corresponding to the clamping screw 12 is formed in a base surface of the housing. The clamping screw 12 extends from the outside of the housing through the threaded hole in the base surface to bear against the base surface of the thin-film shield 6. In this case, the thin-film shield 6 is electrically connected to the second electrode 4 by means of the clamping screw 12; that is, the electrical conduction between the thin-film shield 6 and the second electrode 4 is achieved by means of the clamping screw 12. According to this embodiment, the clamping screw 12 is adjusted to set the contact pressure between the thin-film shield 6 and the insulating coating, thereby ensuring that the thin-film shield 6 is firmly in contact with the insulating coating. The housing shape of the second electrode 4 also serves for electromagnetic shielding.

[0031] In this embodiment, a positioning ring 16, formed integrally with the housing, can be arranged on the inside of the housing base to position the thin-film shielding 6. Preferably, the dimensions of the positioning ring 16 are adapted to the overall dimensions of the thin-film shielding 6. The thin-film shielding 6 is arranged within the positioning ring 16, with a sealing pad 11 positioned between the positioning ring 16 and a side wall of the thin-film shielding 6. In this embodiment, the detection device can further include a rubber washer 5. The edge of the housing is hermetically sealed to the insulating coating section 7 of the detected component by means of the rubber washer 5.The sealing pad 11 between the positioning ring 16 and the side wall of the thin-film shielding 6 and the rubber washer 5 between the edge of the housing and the insulating coating section of the detected component serve to seal the interior of the housing.

[0032] Based on the embodiment described above, this embodiment further incorporates an inlet tube and an outlet tube on the housing. An inlet valve 13 is arranged on the inlet tube, while the outlet tube is connected to a vacuum pump via an outlet valve 14. The inlet valve 13 is closed before the experiment, and a vacuum is created inside the housing using the vacuum pump. The housing is internally sealed to maintain the vacuum, causing the coating at the defect to detach from the component by a certain distance and preventing the dissipation of polarization charges from the surface of the detected component. As a result, the defect can be measured more easily.

[0033] In this embodiment, the detection device can further include a signal amplifier 15. The piezoelectric thin film 8 is connected to a signal analysis device via the signal amplifier 15. The signal analysis device can include an oscilloscope and / or a computer.

[0034] Fig. Figure 3(a) illustrates a component with a coating delamination defect in its insulating coating. If the component exhibits the coating delamination defect, the delamination coating can be separated from the component body after a vacuum has been created in the housing. A high DC voltage is applied between the electrodes to polarize the component, inducing heterocharges of equal magnitude on the outside of the coating and on the interface between the coating and the component body. After the action of a narrow pulse, the Fig.3(b) A curve graph of the measured stress waves caused by a PVDF layer. The first peak of the curve is a charge stress pulse wave occurring at the outer surface of the coating. The second peak is a charge stress pulse wave (a wave generated due to coating delamination) occurring at the interface between the coating and the component body. The appearance of the second wave indicates that delamination is occurring. Because the wave source is located at the defect and the emitted waves are not subject to reflection or transmission, unadulterated and regular stress waves can be measured using the piezoelectric thin film 8.

[0035] Various embodiments are described here in a progressive manner. The description of each embodiment focuses on the differences from other embodiments, while allowing for reciprocal reference to identical and similar parts of different embodiments.

[0036] Specific embodiments are used here to explain the principles and implementations of the present disclosure. The description of the preceding embodiments is intended solely to aid understanding of the process and core ideas of the present disclosure. Moreover, various modifications to the specific implementations and within the scope of protection of the application may be made by those skilled in the art, in accordance with the ideas of the present disclosure. Finally, the contents of this description should not be interpreted as limitations of the present disclosure.

Claims

[1] Device for non-destructive detection of the delamination of a coating on a component, comprising: a high-voltage power source, a tension screw, a narrow pulse generator, a first electrode and a second electrode, a thin-film shield and a piezoelectric thin film arranged inside the thin-film shield; wherein the high-voltage power source is connected to the first electrode by means of a high-voltage resistor and is configured to apply a DC high voltage to the first electrode; The narrow pulse generator is connected to the first electrode via a high-voltage capacitor and is configured to apply a narrow pulse with a width smaller than a setpoint to the first electrode; the second electrode is connected to the high-voltage power source and a ground connection of the pulse generator, and the second electrode is a housing with one open side facing upwards; the thin-film shielding is arranged in the housing; a threaded hole suitable for the clamping screw is formed in a base surface of the housing; the clamping screw extends from the outside of the housing through the threaded hole in the base surface of the housing to support itself against the base surface of the thin-film shielding; the thin-film shield is made of an electrically conductive material and serves for electromagnetic shielding; wherein an outer side surface of an upper end of the thin-film shield abuts an insulating coating section of a detected component, while an inner side surface of the upper end of the thin-film shield abuts the piezoelectric thin film, wherein the thin-film shield is further connected to the second electrode; wherein the detected component comprises a body section and the insulating coating section; the piezoelectric thin film is configured to convert detected sound waves into an electrical voltage signal; wherein the voltage signal is analyzed to determine the delamination of the insulating coating of the detected component; and wherein If the detected component is a metal component, the first electrode is the body section of the metal component; whereas, if the detected component is a polymer component, the detection device further comprises: a metal plate serving as the first electrode and adjacent to the body section of the polymer component. [2] Device for non-destructive detection of the delamination of a coating on a component according to claim 1, further comprising: a wave-absorbing block arranged within the thin-film shielding, wherein the wave-absorbing block is adjacent to the piezoelectric thin film. [3] Device for non-destructive detection of the delamination of a coating on a component according to claim 2, further comprising: a rubber pad arranged between an inner base surface of the thin-film shielding and the wave-absorbing block. [4] Device for non-destructive detection of the delamination of a coating on a component according to claim 1, wherein a positioning ring formed integrally with the housing is arranged on an inner side of the bottom of the housing; the thin-film shielding is arranged in the positioning ring; and a sealing pad is arranged between the positioning ring and a side wall of the thin-film shielding. [5] Device for non-destructive detection of the delamination of a coating on a component according to claim 4, which further comprises a rubber washer, wherein the edge of the housing is hermetically sealed to the insulating coating section of the detected component by means of the rubber washer. [6] Device for non-destructive detection of the delamination of a coating on a component according to claim 5, wherein an inlet tube and an outlet tube are arranged on the housing; and the outlet tube is connected to a vacuum pump. [7] Device for non-destructive detection of the delamination of a coating on a component according to claim 6, which further comprises an inlet valve and an outlet valve, wherein the inlet valve is arranged in the inlet pipe; and the outlet pipe is connected to the vacuum pump by means of the outlet valve. [8] Device for non-destructive detection of the delamination of a coating on a component according to claim 1, which further comprises a signal amplifier, wherein the piezoelectric thin film is connected to a signal analysis device by means of the signal amplifier. [9] Device for non-destructive detection of the delamination of a coating on a component according to claim 8, wherein the signal analysis device comprises an oscilloscope and / or a computer.

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