Preparation method of high-interface wettability composite micro-nano texture for thermal barrier coating

Abstract

The invention discloses a preparation method of a composite micro-nano texture for high interface wettability of a thermal barrier coating, and aims to solve the problems that the interface of a ceramic coating and a metal bonding layer is easy to lose efficacy, and the wettability of ceramic liquid drops is poor due to a laser texturing process. The preparation method comprises the following steps: 1, preparing the bonding layer on the surface of the metal matrix by adopting a spraying process; 2, performing texturing treatment on the surface of the bonding layer by adopting pulse laser; thirdly, the bonding layer subjected to texturing treatment is cleaned; 4, depositing an Al2O3 film on the surface of the cleaned bonding layer by adopting a chemical vapor deposition process; 5, carrying out annealing treatment on the coated substrate; and 6, spraying on the surface of the Al2O3 thin film on the coating substrate by adopting a spraying process to form a ceramic top layer. According to the method, the wettability of ceramic liquid drops on the surface of the textured bonding layer can be improved, defects at an interface are reduced, the bonding strength of the bonding layer and a ceramic top layer is improved, thermal stress concentration at the interface is relieved, and generation and extension of cracks are reduced, so that the service life of the coating is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of thermal barrier coating technology, and particularly relates to a method for preparing composite micro / nano textures with high interfacial wettability for thermal barrier coatings. Background Technology

[0002] With the development of science and technology and the continuous upgrading of aviation equipment, the requirements for thrust and thrust-to-weight ratio of aero engines are becoming increasingly stringent, leading to a continuous increase in the turbine inlet gas temperature. High-temperature turbine alloy blades are core components in aero engines with extremely demanding temperature and load requirements, and are also a key bottleneck restricting their development. Thermal barrier coatings (TBCs) made of low thermal conductivity ceramics are now widely used in hot gas flow metal components of gas turbine engines to provide thermal insulation. Using TBCs (100 to 500 micrometers thick) and internal cooling of the underlying high-temperature alloy components can significantly reduce the surface temperature of the high-temperature alloy (100 to 300°C). This allows modern gas turbine engines to operate in environments above the melting temperature of the high-temperature alloy (approximately 1300°C), thereby improving engine efficiency and performance. Furthermore, at slightly lower operating temperatures, the TBC helps reduce the temperature of the metal substrate, making engine components more durable.

[0003] The thermal barrier coating (TBC) assembly consists of three layers: a ceramic topcoat, a metal bonding layer, and an alloy substrate. Each layer possesses significantly different physical, thermal, and mechanical properties, making it inherently more complex than a single metal or all-ceramic assembly. The metal bonding layer, acting as a transition layer between the metal substrate and the ceramic topcoat, plays a crucial role in the entire TBC system. It mitigates the thermal expansion mismatch between the ceramic topcoat and the substrate, alleviates thermal stress, and provides oxidation resistance, corrosion resistance, and substrate protection. Furthermore, the metal bonding layer bonds firmly and tightly to both the substrate surface and the ceramic layer, ensuring a defect-free interface between the bonding layer and the topcoat. This limits the peeling of the ceramic topcoat, thereby improving the TBC's durability at high temperatures. However, failure issues in industrial applications of TBCs still frequently occur at the interface between the ceramic coating and the metal bonding layer, significantly impacting their application.

[0004] In atmospheric plasma spraying, the bonding between the ceramic layer and the metal adhesive layer is primarily mechanical, resulting in relatively low bond strength. This limits the application of atmospheric plasma spraying systems for thermal barrier coatings under more complex and demanding conditions such as external stress, thermal shock, and erosion. Laser texturing technology is widely used to modify the surface structure of the adhesive layer. By introducing specific micron or submicron-level surface structures, such as pits, grooves, and micropores, on the adhesive layer surface, the mechanical interlocking force between the adhesive layer and the ceramic layer can be effectively improved, thereby enhancing the interfacial bonding strength. These microstructures not only provide more bonding sites for the coating but also help alleviate thermal stress concentration by adjusting the stress distribution at the interface, thus improving the thermal barrier coating system's resistance to thermal cycling. However, textured adhesive layers often have increased surface roughness and more complex surface morphology, resulting in poor wettability of ceramic droplets. This also increases the likelihood of defects when sprayed droplets spread on the surface, such as pores and cracks caused by insufficient filling of ceramic powder particles in the textured grooves and uneven spreading of textured edges. These defects will affect the bonding strength and become the cause of crack propagation and spalling failure during service. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of easy failure at the interface between the ceramic coating and the metal bonding layer, and poor wettability of ceramic droplets caused by laser texturing process. The invention provides a method for preparing composite micro-nano textures with high interfacial wettability for thermal barrier coatings. This method can reduce interfacial defects between the ceramic layer and the bonding layer during spraying, make the molten droplets spread evenly on the surface of the bonding layer, and improve the bonding strength between the metal bonding layer and the top ceramic layer of the thermal barrier coating.

[0006] The method for preparing composite micro / nano textures with high interfacial wettability for thermal barrier coatings according to the present invention is implemented according to the following steps:

[0007] Step 1: Prepare an adhesive layer on the surface of the metal substrate using a spraying process;

[0008] Step 2: The surface of the adhesive layer is textured (at the micrometer scale) using a pulsed laser. The texture is composed of a combination of linear grooves and micro-pit structures, resulting in a textured adhesive layer.

[0009] Step 3: Clean the textured adhesive layer to obtain the cleaned adhesive layer;

[0010] Step 4: Deposit an Al2O3 thin film on the cleaned adhesive layer surface using chemical vapor deposition to obtain the coating substrate;

[0011] Step 5: Anneal the coating substrate at a temperature of 300~500℃;

[0012] Step 6: A ceramic top layer is formed by spraying Al2O3 thin film on the coating substrate using a spraying process, thereby completing the preparation method of composite micro-nano texture for high interfacial wettability of thermal barrier coating;

[0013] The ceramic top layer mentioned in step six is ​​a yttrium oxide stabilized zirconium oxide layer, a zirconate layer, a cerate layer, a tantalate layer, a hexaaluminate layer, a niobate layer, or a chromate layer.

[0014] The adhesive layer of the thermal barrier coating of the present invention has undergone laser texturing and nanoscale wettability film coating treatment. From the surface layer to the inner layer, it consists of a ceramic top layer, a nanoscale coating layer, an adhesive layer and a high-temperature alloy substrate. The nanoscale thickness coating and the micron-scale textured adhesive layer form a micro-nano composite structure interface.

[0015] The textured pattern and its process method for high interfacial wettability in thermal barrier coatings provided by this invention involve laser texturing the surface of the adhesive layer. This increases the surface roughness of the adhesive layer and the contact area with the ceramic top layer, providing more mechanical interlocking points for the ceramic layer particles in the subsequent atmospheric plasma spraying. A nanoscale alumina film is then prepared on the textured surface using chemical vapor deposition, thereby improving the interfacial structure between the adhesive layer and the ceramic top layer. The α-Al₂O₃ film formed on the adhesive layer surface not only improves the coating's oxidation resistance but also, due to the excellent wettability of the alumina film, improves the wettability of the adhesive layer surface. This allows molten droplets to spread more quickly and evenly on the adhesive layer surface during the spraying of the ceramic top layer material, reducing defects at the interface. The synergistic effect of laser texturing and wettability-modified coating on the adhesive layer surface further enhances the bonding strength between the adhesive layer and the ceramic top layer, alleviates thermal stress concentration at the interface, reduces crack generation and propagation, and extends the service life of the coating. Attached Figure Description

[0016] Figure 1 This is a schematic cross-sectional view of the composite micro / nano texture for high interfacial wettability of thermal barrier coatings prepared according to the present invention;

[0017] Figure 2 This is a schematic diagram of the surface texture of the adhesive layer after laser etching texture in Example 1;

[0018] Figure 3 This is a schematic diagram of the surface texture of the adhesive layer after laser etching texture in Example 2;

[0019] Figure 4 This is a cross-sectional scanning electron microscope image of the thermal barrier coating prepared in Example 2. Detailed Implementation

[0020] Specific Implementation Method 1: The method for preparing composite micro / nano textures with high interfacial wettability in thermal barrier coatings according to this implementation method is carried out according to the following steps:

[0021] Step 1: Prepare an adhesive layer on the surface of the metal substrate using a spraying process;

[0022] Step 2: The surface of the adhesive layer is textured (at the micrometer scale) using a pulsed laser. The texture is composed of a combination of linear grooves and micro-pit structures, resulting in a textured adhesive layer.

[0023] Step 3: Clean the textured adhesive layer to obtain the cleaned adhesive layer;

[0024] Step 4: Deposit an Al2O3 thin film on the cleaned adhesive layer surface using chemical vapor deposition to obtain the coating substrate;

[0025] Step 5: Anneal the coating substrate at a temperature of 300~500℃;

[0026] Step 6: A ceramic top layer is formed by spraying Al2O3 thin film on the coating substrate using a spraying process, thereby completing the preparation method of composite micro-nano texture for high interfacial wettability of thermal barrier coating;

[0027] The ceramic top layer mentioned in step six is ​​a yttrium oxide stabilized zirconium oxide layer, a zirconate layer, a cerate layer, a tantalate layer, a hexaaluminate layer, a niobate layer, or a chromate layer.

[0028] In this embodiment, the ceramic top layer is preferably a yttrium oxide stabilized zirconium oxide layer, a lanthanum zirconate layer, a samarium zirconate layer, a gadolinium zirconate layer, or a lanthanum cerate layer.

[0029] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the adhesive layer in step one is a (Ni,Pt)Al alloy layer, a NiCrAlY alloy layer, a NiCoCrAlY alloy layer, and a NiCoCrAlYTa alloy layer, and the thickness of the adhesive layer is 40~60μm.

[0030] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that it uses atmospheric plasma spraying in step 1. The spraying process parameters are as follows: spraying current is 450~700A, spraying voltage is 60~80V, primary gas Ar flow rate is 40~60slpm, secondary gas H2 flow rate is 2~9slpm, carrier argon flow rate is 40~50slpm, spray gun moving speed is 80~120 mm / s, powder feeding rate is 25~50g / min, and spraying distance is 90~120mm.

[0031] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the textured pattern in step two is formed by linear grooves creating a grid, with micro-pits located in the middle of the grid's mesh.

[0032] In this embodiment, the mesh shape is a regular hexagon or other polygon. Regular hexagonal or other polygonal mesh patterns are advantageous for laser scanning processing; the regular hexagonal pattern structure mimics the stable structure of a honeycomb, and compared to a square with the same circumcircle, the planar tessellation of a regular hexagon increases the length of the mesh lines, resulting in more significant advantages in stress dispersion and crack suppression.

[0033] Specific Implementation Method 5: This implementation method differs from Specific Implementation Methods 1 to 4 in that in step 2, the wavelength of the pulsed laser is controlled to be 1064nm, the repetition frequency is 20kHz, the focal length is 150~250mm, the scanning speed is 500~700mm / s, the power is 25~30W, and the number of repeated path scans is 2~4 times.

[0034] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the width of the linear groove in step two is 12~30μm and the depth is 10~20μm.

[0035] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the thickness of the Al2O3 film in step four is 50~100nm.

[0036] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One through Six in that the process of depositing an Al2O3 thin film on the cleaned adhesive layer surface using chemical vapor deposition in step four is as follows:

[0037] The precursors were aluminum acetylacetonate (Al(acac)3), CO2, and H2 gas. The evaporation temperature of Al(acac)3 was controlled at 180℃, and the flow rates of H2 and CO2 gas were 1.8 × 10⁻⁶. -6 m 3 s -1 The heating temperature of the substrate is 800~1000℃.

[0038] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the annealing time in step five is 40 to 80 minutes.

[0039] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that the thickness of the ceramic top layer in step 6 is 200~300μm.

[0040] Specific Implementation Method Eleven: This implementation method differs from Specific Implementation Methods One through Ten in that step six employs an atmospheric plasma spraying process. The spraying process parameters are as follows: spraying current is 450~700A, spraying voltage is 60~80V, primary gas Ar flow rate is 40~60slpm, secondary gas H2 flow rate is 2~9slpm, carrier argon flow rate is 40~50slpm, spray gun moving speed is 80~120 mm / s, powder feed rate is 25~50g / min, and spraying distance is 90~120mm.

[0041] Example 1: The method for preparing composite micro / nano textures with high interfacial wettability for thermal barrier coatings in this example is implemented according to the following steps:

[0042] Step 1: Using high-temperature alloy K465 as the substrate, the substrate is a cylinder with dimensions of Φ20mm×10mm. The dome surface of the substrate is roughened by sandblasting. NiCoCrAlY powder with a particle size of 10~50 μm is used to prepare a 50 μm thick bonding layer on the dome surface of the substrate by atmospheric plasma spraying. The process parameters are: spraying current of 500 A, spraying voltage of 65 V, primary gas Ar flow rate of 55 slpm, secondary gas H2 flow rate of 2 slpm, carrier argon flow rate of 45 slpm, spray gun moving speed of 100 mm / s, powder feed rate of 28 g / min, and spraying distance of 110 mm.

[0043] Step 2: Laser texturing of the adhesive layer using nanosecond lasers, resulting in surface texture patterns such as... Figure 2 As shown, the texture pattern is a square grooved grid with circular micro-pits processed at the center of the grid. The side length of the square in the texture pattern and the spacing between the micro-pits are both 300 μm. The distance between the center of the groove and the center of the micro-pit is 150 μm. The groove width is 60 μm and the groove depth is 16 μm. The diameter of the circular micro-pit is 59 μm and the depth of the circular micro-pit is 16 μm. The nanosecond laser process parameters are: laser wavelength 1064 nm, repetition frequency 20 kHz, focal length 220 mm, scanning speed 600 mm / s, power 25 W, and the number of repeated path scans is 3.

[0044] Step 3: After the texturing treatment is completed, rinse the treated surface with deionized water to remove surface dust and larger particles. Then, immerse it in acetone and anhydrous ethanol in sequence for ultrasonic cleaning for 10 min. After ultrasonic cleaning, dry it at 60℃ to obtain the cleaned adhesive layer.

[0045] Step 4: Prepare a 200 nm thick Al2O3 film on the surface of the adhesive layer as a nanoscale wettable film material via chemical vapor deposition (CVD). The CVD process is as follows: use aluminum acetylacetonate (Al(acac)3) and CO2 and H2 gases as precursors to deposit an α-Al2O3 film in a vapor deposition chamber. Before deposition, the substrate needs to be heated to 950°C using a heating plate and maintained until CVD is complete. The evaporation temperature of the Al(acac)3 precursor is 180°C. Ar gas is introduced into the deposition chamber at a flow rate of 1.65 × 10⁻⁶. -6 m 3 s -1 The flow rates of H2 and CO2 gases are 1.8 × 10⁻⁶ respectively. -6 m 3 s -1 The molar fraction of CO2 is 50% (i.e., the molar ratio of H2 to CO2 is 1:1); the total pressure in the deposition chamber is maintained at 0.4 kPa, and the temperature of the feed pipe and nozzle is maintained at 250℃ to prevent the precursor vapor from condensing, thus obtaining the coating substrate;

[0046] Step 5: After chemical vapor deposition, the substrate is heat-treated. The coated sample is placed in a muffle furnace and heated to 400°C at a heating rate of 10°C / min. It is held at this temperature for 60 min and then cooled down with the furnace. After cooling to room temperature, it is taken out.

[0047] Step Six: On the surface of the adhesive layer after laser texturing, coating, and heat treatment, a 300 μm thick ceramic top layer is prepared by atmospheric plasma spraying using yttrium oxide-stabilized zirconia ceramic powder with a particle size of 10-50 μm. The process parameters are: spraying current of 650 A, spraying voltage of 75 V, primary gas Ar flow rate of 43 slpm, secondary gas H2 flow rate of 7 slpm, carrier argon flow rate of 45 slpm, spray gun moving speed of 100 mm / s, powder feed rate of 40 g / min, and spraying distance of 100 mm. This completes the preparation method of composite micro / nano textures with high interfacial wettability for thermal barrier coatings.

[0048] In this embodiment, the surface of the high-temperature alloy substrate material is pretreated. The pretreatment method is as follows: the substrate surface is polished with silicon carbide sandpaper to remove the surface oxide layer, processing marks and impurities. After polishing, it is ultrasonically cleaned in acetone and alcohol for 5-10 minutes to remove debris and grease from the polishing process. After the substrate is dried, the surface is roughened by sandblasting with brown fused alumina.

[0049] This embodiment conducts a coating adhesion strength test on the substrate with the thermal barrier coating obtained in step six. A Φ20×30 mm tensile test bar is used. The bonding surface of the tensile test bar should be ground smooth and mechanically cleaned to remove contaminants. The bonding surface is then sandblasted to increase surface roughness. The sprayed coating sample is adhered to the tensile test bar using adhesive, and excess adhesive is wiped away. The sprayed coating sample and the tensile test bar should be parallel and aligned, and held in place until the adhesive cures. The coating adhesion strength (R0) is tested using an electronic universal tensile testing machine. H A tensile load (MPa) was applied at a tensile displacement rate of 0.015 mm / s until the specimen fractured, and the maximum applied load was recorded. The bonding strength of the coating is equal to the maximum load divided by the cross-sectional area. The tested interfacial bonding strength of the sample's coating is greater than 45 MPa.

[0050] In this embodiment, the thermal barrier coating with substrate obtained in step six was subjected to a thermal cycling performance test. The test was conducted according to standard GB / T 42259-2022, with a test temperature of 1100℃ and a duration of 10 minutes for both high and low temperatures. The test results showed that the critical number of peeling cycles for the sample was greater than 3000.

[0051] Example 2: The method for preparing composite micro / nano textures with high interfacial wettability for thermal barrier coatings in this example is implemented according to the following steps:

[0052] Step 1: Using high-temperature alloy K465 as the substrate, the substrate is a cylinder with dimensions of Φ20mm×10mm. The dome surface of the substrate is roughened by sandblasting. NiCoCrAlY powder with a particle size of 10~50 μm is used to prepare a 50 μm thick bonding layer on the dome surface of the substrate by atmospheric plasma spraying. The process parameters are: spraying current of 500 A, spraying voltage of 65 V, primary gas Ar flow rate of 55 slpm, secondary gas H2 flow rate of 2 slpm, carrier argon flow rate of 45 slpm, spray gun moving speed of 100 mm / s, powder feed rate of 28 g / min, and spraying distance of 110 mm.

[0053] Step 2: Laser texturing of the adhesive layer using nanosecond lasers, resulting in surface texture patterns such as... Figure 3 As shown, the texture pattern consists of circular micro-pits processed within a regular hexagonal grid. The diameter of the circumcircle of the regular hexagon and the spacing between the micro-pits are both 300 μm. The center of the micro-pit is located at the center of the regular hexagon. The groove width is 60 μm, the groove depth is 16 μm, the micro-pit diameter is 59 μm, and the micro-pit depth is 16 μm. The nanosecond laser process parameters are: laser wavelength 1064 nm, repetition frequency 20 kHz, focal length 220 mm, scanning speed 600 mm / s, power 25 W, and the number of repeated path scans is 3.

[0054] Step 3: After the texturing treatment is completed, rinse the treated surface with deionized water to remove surface dust and larger particles. Then, immerse it in acetone and anhydrous ethanol in sequence for ultrasonic cleaning for 10 min. After ultrasonic cleaning, dry it at 60℃ to obtain the cleaned adhesive layer.

[0055] Step 4: An Al₂O₃ film with a thickness of 200 nm is deposited on the cleaned adhesive layer surface by chemical vapor deposition. The chemical vapor deposition process is as follows: α-Al₂O₃ film is deposited in the vapor deposition chamber using aluminum acetylacetonate (Al(acac)₃) and CO₂ and H₂ gases as precursors. Before deposition, the sample substrate needs to be heated to 950℃ using a heating plate and maintained until the chemical vapor deposition is complete. The evaporation temperature of the Al(acac)₃ precursor is 180℃. Ar gas is introduced into the deposition chamber at a flow rate of 1.65 × 10⁻⁶. -6 m 3 s -1 The flow rates of both H2 and CO2 gases are 1.8 × 10⁻⁶. -6 m 3 s -1 The molar fraction of CO2 is 0.5; the total pressure in the deposition chamber is maintained at 0.4 kPa, and the temperature of the feed pipe and nozzle is maintained at 250℃ to prevent precursor vapor condensation, thus obtaining the coating substrate;

[0056] Step 5: After chemical vapor deposition, heat-treat the coating substrate by placing it in a muffle furnace and heating it to 400°C at a heating rate of 10°C / min for 60 min. Then, cool it down with the furnace until it reaches room temperature and remove it from the furnace.

[0057] Step Six: On the surface of the adhesive layer after laser texturing, coating, and heat treatment, a 300 μm thick ceramic top layer is prepared by atmospheric plasma spraying using lanthanum zirconate (La2Zr2O7) ceramic powder with a particle size of 10~50 μm. The process parameters are: spraying current of 650 A, spraying voltage of 75 V, primary gas Ar flow rate of 43 slpm, secondary gas H2 flow rate of 7 slpm, carrier argon flow rate of 45 slpm, spray gun moving speed of 100 mm / s, powder feed rate of 40 g / min, and spraying distance of 100 mm. This completes the preparation method of composite micro-nano textures with high interfacial wettability for thermal barrier coatings.

[0058] This embodiment describes the preparation and characterization of the thermal barrier coating sample obtained in step six using scanning electron microscopy, as shown in the attached figure. Figure 4 As shown.

[0059] This embodiment conducts a bonding strength test on the thermal barrier coating with substrate obtained in step six. A Φ20×30 mm tensile test bar is used. The bonding surfaces of the tensile test bar should be ground smooth and mechanically cleaned to remove contaminants. The bonding surfaces are then sandblasted to increase surface roughness. The sprayed coating sample is adhered to the tensile test bar using adhesive, and excess adhesive is wiped away. The sprayed coating sample and the tensile test bar should be parallel and aligned, and held in place until the adhesive cures. The bonding strength (R0) of the coating is tested using an electronic universal tensile testing machine. H A tensile load (MPa) was applied at a tensile displacement rate of 0.015 mm / s until the specimen fractured, and the maximum applied load was recorded. The bonding strength of the coating is equal to the maximum load divided by the cross-sectional area. The tested interfacial bonding strength of the sample's coating is greater than 45 MPa.

[0060] In this embodiment, the thermal barrier coating with substrate obtained in step six was subjected to a thermal cycling performance test. The test was conducted according to standard GB / T 42259-2022, with a test temperature of 1100℃ and a duration of 10 minutes for both high and low temperatures. The test results showed that the critical number of peeling cycles for the sample was greater than 3000.

Claims

1. A method for preparing a composite micro-nano-texture for high interfacial wetting of thermal barrier coatings, characterized in that The preparation method of the composite micro-nano texture for high interfacial wettability of thermal barrier coating is realized according to the following steps: Step one, a bonding layer is prepared on the surface of the metal substrate by a spraying process; Step two, the surface of the bonding layer is textured by pulse laser, the texture pattern is composed of linear grooves and micro-pit recess structures, and a textured bonding layer is obtained; Step three, the textured bonding layer is cleaned to obtain a cleaned bonding layer; Step four, an Al2O3 film is deposited on the surface of the cleaned bonding layer by a chemical vapor deposition process, and a film-coated substrate is obtained; Step five, the film-coated substrate is annealed at a temperature of 300-500 DEG C; Step six, a ceramic top layer is sprayed on the surface of the Al2O3 film on the film-coated substrate by a spraying process, thereby completing the preparation method of the composite micro-nano texture for high interfacial wettability of thermal barrier coating. The ceramic top layer in step six is a yttria-stabilized zirconia layer, a zirconate layer, a cerate layer, a tantalate layer, a hexaaluminate layer, a niobate layer, or a chromate layer.

2. The method of claim 1, wherein The bonding layer in step one is a (Ni, Pt) Al alloy layer, a NiCrAlY alloy layer, a NiCoCrAlY alloy layer, or a NiCoCrAlYTa alloy layer, and the thickness of the bonding layer is 40-60 μm.

3. The method of claim 1, wherein In step two, the texture pattern is a grid formed by linear grooves, and the micro-pit recesses are located in the middle of the mesh.

4. The method of claim 1, wherein In step two, the wavelength of the pulse laser is controlled to be 1064 nm, the repetition frequency is 20 kHz, the focal length is 150-250 mm, the scanning speed is 500-700 mm / s, the power is 25-30 W, and the number of repeated path scanning is 2-4 times.

5. The method of claim 1, wherein In step two, the groove width of the linear grooves is 12-30 μm, and the groove depth is 10-20 μm.

6. The method of claim 1, wherein In step four, the thickness of the Al2O3 film is 50-100 nm.

7. The method of claim 1, wherein the method further comprises In step four, the process of depositing the Al2O3 film on the surface of the cleaned bonding layer by the chemical vapor deposition process is as follows: The precursor is acetylacetone aluminum Al(acac)3, CO2 and H2 gas, the evaporation temperature of Al(acac)3 is controlled to be 180°C, the flow rates of H2 and CO2 gas are respectively 1.8*10 -6 m 3 s -1 , and the heating temperature of the substrate is 800-1000°C.

8. The method of claim 1, wherein In step five, the annealing time is 40-80 min.

9. The method of claim 1, wherein In step six, the thickness of the ceramic top layer is 200-300 μm.

10. The method of claim 1, wherein In step six, the atmospheric plasma spraying process is used, and the spraying process parameters are as follows: the spraying current is 450-700 A, the spraying voltage is 60-80 V, the flow rate of the primary gas Ar is 40-60 slpm, the flow rate of the secondary gas H2 is 2-9 slpm, the carrier argon flow rate is 40-50 slpm, the spray gun moving speed is 80-120 mm / s, the powder feeding rate is 25-50 g / min, and the spraying distance is 90-120 mm.

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