Method for removing MCrAlY bonding layer

Abstract

The invention relates to the technical field of adhesive layer removal, in particular to an MCrAlY adhesive layer removal method. The MCrAlY bonding layer removal method provided by the invention comprises the following steps: a pretreatment step, wherein surface activation is carried out on an MCrAlY bonding layer; an electrochemical removal step: taking the metal sample piece with the MCrAlY bonding layer as an anode, taking an inert electrode as a cathode, placing the anode and the cathode in an electrolyte to form a loop, and electrifying for electrolysis so as to remove the MCrAlY bonding layer on the surface of the metal sample piece; wherein the electrolyte comprises the following components: H < + >, Fe < 3 + >, NO3 <->, ethylenediamine tetraacetic acid, halide ions and a surfactant. According to the MCrAlY bonding layer removing method provided by the invention, the MCrAlY bonding layer on the metal sample piece can be accurately and effectively removed.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesive layer removal, in particular to a method for removing an MCrAlY adhesive layer. Background Art

[0002] Because high-temperature alloy blades, single-crystal blades, and other high-temperature components are inherently expensive, their manufacturing costs far exceed the cost of applying a bonding layer. Simply scrapping a high-temperature component due to an unsatisfactory bonding layer would be a significant waste of resources. Therefore, removing the old bonding layer and applying a new one would extend the service life of the metal substrate, enabling the remanufacturing and life extension of high-temperature components. This is of great significance for the overhaul of engines, gas turbines, and other high-temperature components.

[0003] However, existing methods for removing the adhesive layer are difficult to remove the adhesive layer accurately and effectively. Summary of the Invention

[0004] The object of the present invention is to provide a method for removing an MCrAlY bonding layer, so as to alleviate the technical problem in the prior art of removing the bonding layer that it is difficult to remove the MCrAlY bonding layer accurately and effectively.

[0005] The present invention provides a method for removing an MCrAlY bonding layer, comprising:

[0006] A pre-treatment step for performing surface activation on the MCrAlY bonding layer;

[0007] In the electrochemical removal step, the metal sample with the MCrAlY bonding layer is used as an anode, and the inert electrode is used as a cathode. The anode and the cathode are placed in an electrolyte to form a circuit, and power is applied to perform electrolysis to remove the MCrAlY bonding layer on the surface of the metal sample; wherein the electrolyte contains H + 、Fe 3+ 、NO3 - , ethylenediaminetetraacetic acid, halogen ions and surfactants.

[0008] Preferably, as an embodiment, the halogen ion comprises F - 、Cl - and Br - One or more of .

[0009] Preferably, as an implementation method, the electrolyte contains HNO3, Fe(NO3)3, a halogen compound, ethylenediaminetetraacetic acid and the surfactant.

[0010] Preferably, as an implementation method, in the electrolyte, the mass concentration of the HNO3 in the non-aqueous component is 25-40%, the mass concentration of the Fe(NO3)3 in the non-aqueous component is 10-30%, the mass concentration of the halogen compound in the non-aqueous component is 25-35%, and the mass concentration of the ethylenediaminetetraacetic acid in the non-aqueous component is 20-30%.

[0011] Preferably, as an implementation method, the electrochemical removal step adopts a DC constant voltage mode for electrolysis, with a voltage of 1.2 to 3.4 V and a current density of less than 1000 A / mm 2 , time is 3 to 40 minutes.

[0012] Preferably, as an embodiment, the surfactant comprises sulfonate, HF or NaF.

[0013] Preferably, as an implementation method, the mass concentration of the sulfonate in the non-aqueous component of the electrolyte is 0.1-1%, or the mass concentration of HF in the non-aqueous component of the electrolyte is 5-15%, or the mass concentration of NaF in the non-aqueous component of the electrolyte is 5-15%.

[0014] Preferably, as an implementation method, the pre-treatment step includes: immersing the metal sample with the MCrAlY bonding layer in a nitric acid solution with a mass concentration of 25%, wherein the nitric acid solution contains 0.2-0.5 g / L sodium benzenesulfonate, and the immersion time is 2-10 minutes;

[0015] Alternatively, the pre-treatment step includes: wet sandblasting the surface of the MCrAlY bonding layer, using a pressure of 0.1-0.2 MPa, a grit size of 120 mesh or more, and a grit composition of Al2O3.

[0016] Preferably, as an embodiment, after the electrochemical removal step, the method further comprises: a removal evaluation step, observing the surface of the metal sample after the removal of the MCrAlY bonding layer under a light with an illumination of 300 Lx or more, and the presence of a metallic luster on the surface of the metal sample indicates that the removal is complete;

[0017] And / or, after the electrochemical removal step, the method further comprises: a removal evaluation step of testing the removal effect of the MCrAlY bonding layer using a bluing method.

[0018] Preferably, as an embodiment, after the electrochemical removal step, the method further comprises: a corrosion product removal step, wherein the metal sample after the MCrAlY bonding layer is removed is ultrasonically treated using an ultrasonic wave with a power of less than 1400 W and a frequency of 28 to 80 kHz, and then the sample is wiped with a scouring pad or dust-free paper;

[0019] And / or, between the pre-treatment step and the electrochemical removal step, the method further comprises: a cleaning step of cleaning the metal sample with the MCrAlY bonding layer using deionized water.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The MCrAlY adhesive layer removal method provided by the present invention is due to the presence of H + 、Fe 3+ 、NO3 - , ethylenediaminetetraacetic acid, halogen ions, and surfactants. Therefore, when electrolysis is carried out by power, the MCrAlY bonding layer can be smoothly dissolved in the electrolyte and can fall off under the action of pneumatic stripping. Therefore, the MCrAlY bonding layer on the metal sample can be accurately and effectively removed, so that the metal luster of the substrate is revealed on the surface of the metal workpiece, and the metal workpiece can be directly reused. It is of great significance for the reuse of scrapped blades. It can greatly increase the life of the metal substrate and has strong economic benefits. The present invention has a wide range of applications and has good applicability to MCrAlY coatings prepared by thermal spraying, electron beam physical vapor deposition, and multi-arc ion plating. It is particularly suitable for thermal barrier coating engineering applications in the fields of aviation, aerospace energy, etc.

[0022] It should be noted that the present invention adopts an electrochemical method to remove the MCrAlY bonding layer on the metal sample. Compared with the physical method of removing the MCrAlY bonding layer, the electrochemical method is easy to operate, saves time and labor, has high efficiency, is easy to control the precision, is not easy to damage the metal matrix, is not easy to generate stress, and the equipment used is low in price, which can achieve large-scale production; compared with the chemical method of removing the MCrAlY bonding layer, the solution system is simple and has low concentration, weak corrosiveness, low danger, and the waste liquid is easy to handle, which has environmental advantages and better removal effect; in addition, removing the MCrAlY bonding layer through electrical adjustment control is easier to control. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0024] Figure 1 A first schematic flow chart of a method for removing an MCrAlY bonding layer provided in an embodiment of the present invention;

[0025] Figure 2 A second schematic flow chart of the MCrAlY bonding layer removal method provided in an embodiment of the present invention;

[0026] Figure 3a This is the surface macromorphology of the metal sample with NiCrAlY bonding layer;

[0027] Figure 3b This is the surface macromorphology of the metal sample after removing the NiCrAlY bonding layer;

[0028] Figure 4a This is the surface macromorphology of the metal sample with NiCoCrAlY bonding layer;

[0029] Figure 4b This is the surface macromorphology of the metal sample after partial removal of the NiCoCrAlY bonding layer;

[0030] Figure 5a This is a cross-sectional microscopic diagram of the protected area of ​​the metal sample after the MCrAlY bonding layer is removed;

[0031] Figure 5b This is a schematic diagram of the cross-section of the interface area of ​​the metal sample after removing the MCrAlY bonding layer;

[0032] Figure 5c This is a cross-sectional microscopic diagram of the removal area of ​​the metal sample after removing the MCrAlY bonding layer. DETAILED DESCRIPTION

[0033] At present, the methods for removing the bonding layer on the surface of high-temperature alloy blades, single crystal blades or other high-temperature components are divided into two categories according to the removal principle, namely physical methods and chemical methods. Among them, the physical method of removing the bonding layer is suitable for hard and brittle bonding layers, or locally damaged bonding layers. It is laborious and time-consuming to operate, and it is difficult to control the precision. It is very easy to damage the substrate and easily generate stress. In addition, some special equipment is expensive and cannot be mass-produced. The chemical method of removing the bonding layer has the problems of complex solution system and strong corrosiveness. The operation requires great care and the waste liquid is difficult to handle. In addition, there are problems such as incomplete removal of local locations and difficulty in removing the inner wall.

[0034] Therefore, the present invention provides a method for removing an MCrAlY bonding layer to solve the above technical problems.

[0035] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] The present invention will be further described in detail below through specific implementation examples in conjunction with the accompanying drawings.

[0037] Figure 1 A schematic flow chart of a method for removing an MCrAlY bonding layer provided in an embodiment of the present invention includes:

[0038] S102, a pre-treatment step, is used to activate the surface of the MCrAlY bonding layer.

[0039] Surface activation of the MCrAlY bonding layer can remove pollutants, oxide layers or residues on the surface of the MCrAlY bonding layer, and improve the surface chemical activity, so as to facilitate subsequent electrochemical removal of the MCrAlY bonding layer.

[0040] S104, electrochemical removal step, using the metal sample with the MCrAlY bonding layer as an anode and an inert electrode as a cathode, placing the anode and cathode in an electrolyte to form a circuit, and applying power to electrolyze and remove the MCrAlY bonding layer on the surface of the metal sample; wherein the electrolyte contains H + 、Fe 3+ 、NO3 - , ethylenediaminetetraacetic acid, halogen ions and surfactants.

[0041] Because of the presence of H + 、Fe 3+ 、NO3 - , ethylenediaminetetraacetic acid, halogen ions, and surfactants. Therefore, when electrolysis is carried out by power, the MCrAlY bonding layer can be smoothly dissolved in the electrolyte and can fall off under the action of pneumatic stripping. Therefore, the MCrAlY bonding layer on the metal sample can be accurately and effectively removed, so that the metal luster of the substrate is revealed on the surface of the metal workpiece, and the metal workpiece can be directly reused. It is of great significance for the reuse of scrapped blades. It can greatly increase the life of the metal substrate and has strong economic benefits. The present invention has a wide range of applications and has good applicability to MCrAlY coatings prepared by thermal spraying, electron beam physical vapor deposition, and multi-arc ion plating. It is particularly suitable for thermal barrier coating engineering applications in the fields of aviation, aerospace energy, etc.

[0042] It should be noted that the present invention adopts an electrochemical method to remove the MCrAlY bonding layer on the metal sample. Compared with the physical method of removing the MCrAlY bonding layer, the electrochemical method is easy to operate, saves time and labor, has high efficiency, is easy to control the precision, is not easy to damage the metal matrix, is not easy to generate stress, and the equipment used is low in price, which can achieve large-scale production; compared with the chemical method of removing the MCrAlY bonding layer, the solution system is simple and has low concentration, weak corrosiveness, low danger, and the waste liquid is easy to handle, which has environmental advantages and better removal effect; in addition, removing the MCrAlY bonding layer through electrical adjustment control is easier to control.

[0043] The halogen ions in the above electrolyte may include F - 、Cl - and Br - One or more of .

[0044] The electrolyte may specifically comprise HNO3, Fe(NO3)3, a halogen compound, ethylenediaminetetraacetic acid and a surfactant, wherein HNO3 can provide H + and NO3 - , Fe(NO3)3 can provide Fe 3+ and NO3 - The halogen compound may be HCl or NaCl.

[0045] Specifically, the mass concentration of HNO3 in the non-aqueous component of the electrolyte can be set to 25-40%, and the mass concentration of Fe(NO3)3 in the non-aqueous component of the electrolyte can be set to 10-30%, and the specific values ​​can be selected according to the type of coating; the mass concentration of HCl in the non-aqueous component of the electrolyte is set to 25-35%, and the specific value can be selected according to the type of coating; and the mass concentration of ethylenediaminetetraacetic acid in the non-aqueous component of the electrolyte is set to 20-30%, and the specific value can be selected according to the type of coating.

[0046] In the above step S104, electrolysis can be performed in a DC constant voltage mode, wherein the voltage can be set to 1.2 to 3.4 V, preferably 1.8 to 2.8 V, and more preferably 2 to 2.5 V; the current density can be set to less than 1000 A / mm 2 , preferably 300~600A / mm 2 , more preferably 150 to 300 A / mm 2 ; The time can be set to 3 to 40 minutes, preferably 10 to 30 minutes, more preferably 12 to 18 minutes, and even more preferably 15 minutes.

[0047] Under this parameter, the MCrAlY bonding layer on the metal sample can be removed smoothly.

[0048] The surfactant may be any one of sulfonate, HF and NaF.

[0049] If sulfonate is selected as the surfactant, the mass concentration of sulfonate in the non-aqueous component of the electrolyte can be set to 0.1-1%, preferably 0.3-0.8%, and more preferably 0.5-0.6%; if HF is selected as the surfactant, the mass concentration of HF in the non-aqueous component of the electrolyte can be set to 5-15%, preferably 8-12%, and more preferably 10%; if NaF is selected as the surfactant, the mass concentration of NaF in the non-aqueous component can be set to 5-15%, preferably 8-12%, and more preferably 10%.

[0050] The above-mentioned pre-treatment step can be achieved by physical or chemical methods.

[0051] When the pretreatment step is performed chemically, it can specifically include immersing the metal sample with the MCrAlY bonding layer in a 25% nitric acid solution containing 0.2-0.5 g / L sodium benzenesulfonate for 2-10 minutes. This chemically activates the surface of the MCrAlY bonding layer. The concentration of benzenesulfonic acid is preferably 0.3-0.4 g / L, more preferably 0.35 g / L, and the immersion time is preferably 4-8 minutes, more preferably 5-7 minutes.

[0052] When the pretreatment step is implemented by a physical method, it can specifically include wet sandblasting the surface of the MCrAlY bonding layer, with a pressure of 0.1 to 0.2 MPa, preferably 0.13 to 0.17 MPa, and more preferably 0.15 MPa; the grit mesh size is 120 mesh or more, preferably 200 mesh or more, and more preferably 210 mesh or more; the grit composition is Al2O3, so that the surface activation treatment of the MCrAlY bonding layer can be achieved by the physical method.

[0053] After the above step S104, the above method further includes a removal evaluation step to evaluate the removal effect and determine whether secondary electrochemical removal is required, so as to ultimately achieve the purpose of complete removal.

[0054] As one possible implementation, the removal evaluation step may include observing the surface of the metal sample after removal of the MCrAlY bonding layer under illumination of 300 lux or greater. If the surface of the metal sample exhibits a metallic luster, removal is complete. If the surface does not exhibit a metallic luster, step S104 may be repeated for a short period of electrolytic removal until a metallic luster is achieved.

[0055] As another possible implementation, the removal evaluation step may include: using a bluing method to verify the removal effect of the MCrAlY bonding layer.

[0056] After step S104, the method further includes a corrosion product removal step, in which the metal sample, after removal of the MCrAlY bonding layer, is subjected to ultrasonic treatment using ultrasonic waves with a power of less than 1400 W and a frequency of 28 to 80 kHz. The sample is then wiped with a scouring pad or dust-free paper to remove corrosion products generated by electrolysis. In practice, the corrosion product removal step occurs between step S104 and the removal evaluation step. The power used for corrosion product removal is preferably less than 1100 W, preferably less than 800 W, and the frequency is preferably 40 to 70 kHz, more preferably 50 to 60 kHz.

[0057] And / or, between steps S102 and S104, the method further includes: a cleaning step of cleaning the metal sample with the MCrAlY bonding layer with deionized water until no bubbles or grit remain on the surface of the metal sample.

[0058] Figure 2 A schematic flow chart of a method for removing an MCrAlY bonding layer provided in an embodiment of the present invention includes:

[0059] Sample preparation;

[0060] Pre-treatment;

[0061] Cleaning;

[0062] electrochemical removal;

[0063] Remove corrosion products;

[0064] Removal evaluation; if the assessment shows that the removal is unqualified, return to continue electrochemical removal; if the assessment shows that the removal is qualified, proceed to the next step and other processes;

[0065] Other processes.

[0066] The technical solution of the present invention will be described in detail below through specific embodiments.

[0067] Example 1

[0068] A NiCrAlY bonding layer was thermally sprayed onto a GH4169 high-temperature alloy specimen. The NiCrAlY bonding layer was lightly wet-sandblasted with 0.1 MPa, 200-mesh Al2O3 grit. The specimen was then cleaned with deionized water until no grit remained on the surface. The specimen with the NiCrAlY bonding layer served as the anode and an inert C electrode as the cathode for electrolytic removal. The electrolyte consisted of 25% HNO3, 20% Fe(NO3)3, 20% EDTA, 34.5% HCl, and 0.5% sodium sulfonate (where the percentages are the mass concentrations of the solutes in the anhydrous component of the electrolyte). The electrolysis was performed in a DC constant-potential mode with a voltage of 2.8 V and a current density between 300 and 600 A / mm2. 2 After electrolytic removal, the metal sample was ultrasonically treated with an 800W, 40kHz ultrasonic wave. The metal sample was then wiped clean with a scouring pad or dust-free paper. Observing the surface of the metal sample after de-coating under 300Lx illumination revealed the metallic luster of the substrate.

[0069] The surface macromorphology of the metal sample with NiCrAlY bonding layer is as follows: Figure 3a As shown in the figure, the surface macromorphology of the metal sample after removing the NiCrAlY bonding layer is shown in the figure. Figure 3b As shown, compared Figure 3a and Figure 3b It can be clearly seen that the NiCrAlY bonding layer on the surface of the metal sample has been completely removed.

[0070] Example 2

[0071] A GH4169 high-temperature alloy specimen was used as a metal specimen. A NiCoCrAlY bonding layer was thermally sprayed onto the surface. Protective tape was used to mask half of the specimen and leave the other half exposed to determine the accuracy of NiCoCrAlY bonding layer removal. The NiCoCrAlY bonding layer was lightly wet-sandblasted with 0.1 MPa, 120-mesh Al₂O₃ grit. The specimen was then cleaned with deionized water until no grit remained on the surface. The NiCoCrAlY bonding layer served as the anode and an inert C electrode as the cathode for electrolytic removal. The electrolyte consisted of 25% HNO₃ + 20% Fe(NO₃)₃ + 20% EDTA + 34.5% HCl + 0.5% sodium sulfonate (where percentages are the mass concentrations of the solutes in the anhydrous component of the electrolyte). The electrolysis was performed in a DC constant-potential mode with a voltage of 2.8 V and a current density between 150 and 300 A / mm². 2After electrolytic removal, the metal sample was ultrasonically treated with an 800W, 40kHz ultrasonic wave. The sample was then cleaned with a scouring pad or dust-free paper. Observation of the surface of the sample after removal of the NiCoCrAlY bonding layer under 300LX illumination revealed the metallic luster of the substrate.

[0072] The surface macromorphology of the metal sample with NiCoCrAlY bonding layer is as follows: Figure 4a As shown in the figure, the surface macromorphology of the metal sample after partial removal of the NiCoCrAlY bonding layer is shown in the figure. Figure 4b As shown, compared Figure 4a and Figure 4b It can be clearly seen that the NiCoCrAlY bonding layer on the local surface of the metal sample has been completely removed. In addition, Figure 5a-5c The figure also shows the cross-sectional microscopic diagrams of different areas of the metal sample after the adhesive layer is removed, where Figure 5a This is a cross-sectional microscopic diagram of the protected area of ​​the metal sample after the bonding layer is removed. Figure 5b This is a microscopic cross-sectional diagram of the interface area of ​​the metal sample after the adhesive layer is removed (the interface area refers to the intersection area between the protection area and the removal area). Figure 5c This is a cross-sectional microscopic diagram of the removal area of ​​the metal sample after the adhesive layer is removed. Figure 5a-5c It can be clearly seen that the NiCoCrAlY bonding layer on the surface of the removal area of ​​the metal sample has been completely removed.

[0073] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

[0074] Finally, it should be noted that, in this document, terms such as "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article, or apparatus.

[0075] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to the embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for removing an MCrAlY bonding layer, characterized in that: include: A pre-treatment step for performing surface activation on the MCrAlY bonding layer; In the electrochemical removal step, the metal sample with the MCrAlY bonding layer is used as an anode, and the inert electrode is used as a cathode. The anode and the cathode are placed in an electrolyte to form a circuit, and power is applied to perform electrolysis to remove the MCrAlY bonding layer on the surface of the metal sample; wherein the electrolyte contains H + 、Fe 3+ 、NO3 - , ethylenediaminetetraacetic acid, halogen ions and surfactants.

2. The method for removing the MCrAlY bonding layer according to claim 1, characterized in that: The halide ions include F - 、Cl - and Br - One or more of .

3. The method for removing the MCrAlY bonding layer according to claim 2, characterized in that: The electrolyte contains HNO3, Fe(NO3)3, a halogen compound, ethylenediaminetetraacetic acid and the surfactant.

4. The method for removing the MCrAlY bonding layer according to claim 3, characterized in that: In the electrolyte, the mass concentration of HNO3 in the non-aqueous component is 25-40%, the mass concentration of Fe(NO3)3 in the non-aqueous component is 10-30%, the mass concentration of the halogen compound in the non-aqueous component is 25-35%, and the mass concentration of ethylenediaminetetraacetic acid in the non-aqueous component is 20-30%.

5. The method for removing the MCrAlY bonding layer according to claim 1, characterized in that: The electrochemical removal step adopts a DC constant voltage mode for electrolysis, with a voltage of 1.2 to 3.4 V and a current density of less than 1000 A / mm 2 , time is 3 to 40 minutes.

6. The method for removing the MCrAlY bonding layer according to claim 1, characterized in that: The surfactant comprises sulfonate, HF or NaF.

7. The method for removing the MCrAlY bonding layer according to claim 6, characterized in that: The mass concentration of the sulfonate in the non-aqueous component of the electrolyte is 0.1-1%, or the mass concentration of HF in the non-aqueous component of the electrolyte is 5-15%, or the mass concentration of NaF in the non-aqueous component of the electrolyte is 5-15%.

8. The method for removing the MCrAlY bonding layer according to claim 1, characterized in that: The pre-treatment step includes: immersing the metal sample with the MCrAlY bonding layer in a nitric acid solution with a mass concentration of 25%, wherein the nitric acid solution contains 0.2-0.5 g / L of sodium benzenesulfonate, and the immersion time is 2-10 minutes; Alternatively, the pre-treatment step includes: wet sandblasting the surface of the MCrAlY bonding layer, using a pressure of 0.1-0.2 MPa, a grit size of 120 mesh or more, and a grit composition of Al2O3.

9. The method for removing the MCrAlY bonding layer according to claim 1, characterized in that: After the electrochemical removal step, the method further includes: a removal evaluation step, observing the surface of the metal sample after removal of the MCrAlY bonding layer under a light with an illumination of 300 Lx or more, and the removal is complete when the surface of the metal sample exhibits a metallic luster; And / or, after the electrochemical removal step, the method further comprises: a removal evaluation step of testing the removal effect of the MCrAlY bonding layer using a bluing method.

10. The method for removing the MCrAlY bonding layer according to any one of claims 1 to 9, characterized in that: After the electrochemical removal step, the method further includes: a corrosion product removal step, using ultrasonic waves with a power of less than 1400 W and a frequency of 28 to 80 kHz to ultrasonically treat the metal sample after removing the MCrAlY bonding layer, and then wiping the sample with a scouring pad or dust-free paper; And / or, between the pre-treatment step and the electrochemical removal step, the method further comprises: a cleaning step of cleaning the metal sample with the MCrAlY bonding layer using deionized water.

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