A vertical crack heat insulation coating applied to high temperature environment and a preparation method thereof

Abstract

The application discloses a vertical crack heat insulation plating layer applied to a high-temperature environment and a preparation method thereof. The heat insulation plating layer comprises, from a base body to a surface layer, a metal bonding layer, a diffusion barrier layer, a dense transition layer, a vertical crack functional layer and a microporous heat dissipation layer. The vertical crack functional layer adopts a three-dimensional crack network structure, the crack density is 12-15 pieces per square centimeter, the width is 0.8-1.2 micrometers, the crack depth penetrates through the functional layer, and the material adopts mixed nano particles of Gd2O3-YSZ. The microporous heat dissipation layer is a YSZ material layer with a porosity of 15%-20% and a thickness of 18-22 micrometers. Compared with the performance of a traditional vertical crack coating, the vertical crack heat insulation plating layer has the characteristics of a long thermal cycle life, a large heat insulation temperature difference, a strong oxidation resistance and a low crack propagation rate. The microporous heat dissipation layer and the vertical crack form a synergistic heat dissipation channel, and the heat dissipation efficiency of the heat flow direction is improved by 35%.

Description

Technical Field

[0001] This invention relates to the field of high-temperature protective coating technology, specifically to a vertical crack heat-insulating coating and its preparation method for use in high-temperature environments. Background Technology

[0002] Traditional thermal barrier coatings (TBCs) using plasma spraying to prepare YSZ (yttrium-stabilized zirconia) ceramic layers are prone to spalling failure under thermal cycling conditions due to transverse cracks and layered structures generated during rapid solidification. To address this issue, the industry has proposed the concept of vertical cracks, which actively introduces a network of microcracks distributed along the thickness direction to form a "heat dissipation fin" effect, while utilizing crack deflection mechanisms to alleviate thermal stress. However, existing vertical crack technologies still have the following core drawbacks: (1) Insufficient crack controllability Random distribution problem: Existing technologies (such as Chinese patent CN103451824B) induce cracks by adjusting spraying parameters, but the crack direction, density, and width exhibit random distribution characteristics, leading to increased local stress concentration. Tests show that after 500 thermal cycles at 1100℃, the peeling area of ​​the coating with random cracks reaches 15%, while the ideal vertical crack coating should be controlled within 5%.

[0003] Depth control defects: Although GE's EB-PVD vertical crack coating can achieve columnar intergranular vertical microcracks, the crack depth only reaches 60%-70% of the coating thickness, which cannot form a through heat dissipation channel and has limited improvement in heat insulation efficiency.

[0004] (2) Limitations of the preparation process Highly dependent on equipment: Electron beam physical vapor deposition (EB-PVD) requires vertical cracks to be created in a vacuum environment, the equipment cost is in the tens of millions, and it can only process simple geometric parts, and cannot process complex internal cavity structures.

[0005] Narrow process window: When preparing vertical cracks using atmospheric plasma spraying (APS), parameters such as spraying power, powder feed rate, and cooling rate must be precisely matched. Even slight deviations can lead to crack closure or excessive propagation. Tests conducted by Mitsubishi Heavy Industries in Japan have shown that parameter fluctuations of ±5% can cause crack density changes exceeding 30%.

[0006] (3) Performance synergy contradiction Conflict between thermal insulation and strength: In order to increase crack density and improve heat dissipation, the density of the ceramic layer needs to be reduced, but this will lead to a decrease in the elastic modulus of the coating (from 20GPa to below 10GPa), making it prone to plastic deformation under mechanical load.

[0007] Oxidation resistance degradation: Vertical cracks act as channels for the penetration of oxidizing media, accelerating the growth of TGO (thermally grown oxide) layers. NASA tests show that after 1000 hours of oxidation testing, the TGO thickness of conventional vertical crack coatings reaches 8 μm, twice that of dense coatings, leading to a sharp increase in interfacial stress.

[0008] (4) Poor adaptability to service environment Insufficient high-temperature stability: At temperatures above 1400℃, YSZ ceramics undergo a phase transformation, leading to the collapse of the vertical crack network. Engine test data from Airbus Europe shows that after 200 hours of continuous operation at 1350℃, the traditional vertical crack coating exhibits a 300% increase in crack width and a 40% decrease in thermal insulation performance.

[0009] Thermal shock performance limitations: Under rapid heating and cooling conditions (such as rapid cooling from 1200℃ to room temperature), the existing vertical crack coating has a crack propagation rate of 0.5μm / cycle, which is far higher than the ideal value (≤0.1μm / cycle) and cannot meet the reusability requirements of hypersonic aircraft. Summary of the Invention

[0010] The purpose of this invention is to provide a vertical crack insulation coating for use in high-temperature environments, which has high heat dissipation efficiency, long thermal cycle life, large thermal insulation temperature difference, strong oxidation resistance and low crack propagation rate.

[0011] Another objective of this invention is to provide a method for preparing a vertical crack heat-insulating coating for use in high-temperature environments.

[0012] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A vertical crack heat-insulating coating for use in high-temperature environments comprises, from the substrate to the surface: a metal bonding layer, a diffusion barrier layer, a dense transition layer, a vertical crack functional layer, and a microporous heat dissipation layer. The metal bonding layer is made of a Ni-Co-Cr-Al-Y-Ta alloy; the diffusion barrier layer is used to suppress interdiffusion of elements; the dense transition layer is made of nanostructured YSZ; the vertical crack functional layer adopts a three-dimensional crack network structure with a crack density of 12-15 cracks / cm², a crack width of 0.8-1.2μm, and a crack depth penetrating the functional layer, and is made of a mixture of Gd₂O₃-YSZ nanoparticles; the microporous heat dissipation layer is a YSZ material layer with a porosity of 15%-20% and a thickness of 18-22μm.

[0013] Furthermore, the thickness of the vertical crack functional layer is 78-82 μm, and the Gd content in the mixed nanoparticles is 6-8 mol.

[0014] Furthermore, the metal bonding layer is prepared by low-pressure plasma spraying, with a surface roughness Ra≤3.2μm and a thickness of 22-28μm.

[0015] Furthermore, the diffusion barrier layer is an Al2O3 / YSZ composite layer with a thickness of 4-6 μm.

[0016] Furthermore, the diffusion barrier layer adopts a double-layer gradient structure. The side near the metal bonding layer is a dense Al2O3 layer with a thickness of 2μm; the side near the dense transition layer is a YSZ / Al2O3 mixed layer with a thickness of 3μm. The YSZ / Al2O3 mixed layer is made of nano-mixed powder with an Al2O3 content of 20wt% and the balance being YSZ.

[0017] Furthermore, the thickness of the dense transition layer is 28-32 μm, and the porosity of the dense transition layer is ≤3%.

[0018] Furthermore, the YSZ material in the microporous heat dissipation layer is porous YSZ nanoparticles.

[0019] Furthermore, the mass percentages of the Ni-Co-Cr-Al-Y-Ta alloy are: Ni: 65%, Co: 20%, Cr: 22%, Al: 12%, Y: 0.8%, Ta: 4%. This formulation can reduce the oxidation rate by 50% and increase the coating life by 3 times.

[0020] A method for preparing a vertical crack heat-insulating coating for use in high-temperature environments includes the following steps: Step S1. Sandblast, clean and preheat the substrate.

[0021] Step S2. Preparation of the metal bonding layer: The substrate is fed into a low-pressure plasma spraying system with a vacuum degree ≤10kPa. The equipment process parameters are: power: 32kW; spraying distance: 110mm; powder feeding rate: 25g / min; argon flow rate: 45L / min; hydrogen flow rate: 6L / min; spraying time: 45s. The thickness of the metal bonding layer is controlled by precisely controlling the spraying time.

[0022] Step S3. Prepare a diffusion barrier layer on the surface of the metal bonding layer: The diffusion barrier layer adopts a double-layer gradient structure. A dense Al2O3 layer is sprayed onto the surface of the metal bonding layer using a spray gun. The chemical inertness of Al2O3 isolates the diffusion of alloying elements. A YSZ / Al2O3 mixed layer is sprayed onto the surface of the dense Al2O3 layer. The YSZ / Al2O3 mixed layer is used to improve the interfacial wettability and bonding strength. The YSZ / Al2O3 mixed layer uses nano-mixed powder with an Al2O3 content of 20wt% and the balance being YSZ.

[0023] Step S4. Prepare a dense transition layer on the surface of the diffusion barrier layer: Use a spray gun to spray a dense transition layer on the surface of the diffusion barrier layer. The spray powder is nanostructured YSZ, and the porosity of the dense transition layer is ≤3%.

[0024] Step S5. Prepare a vertical crack functional layer on the surface of the dense transition layer: The vertical crack functional layer adopts a three-dimensional crack network structure with a crack density of 12-15 cracks / cm², a width of 0.8-1.2μm, and a crack depth that penetrates the functional layer; The spraying powder is made of rare earth-doped YSZ, specifically Gd2O3-YSZ, with a Gd content of 6-8 mol%. The spraying powder has a uniform particle size distribution, no agglomerated particles, and a particle size distribution range of D10=15μm, D50=25μm, D90=35μm. 0.5wt% Ni nanoparticles are added to the spraying powder as a crack inducing agent. Optimized spraying parameters: Power: 38kW (15% higher than conventional APS); Spraying distance: 130mm; Powder feed rate: 32g / min; Side-blowing cooling: Argon flow rate 25L / min, cooling distance 50mm; Scanning strategy: Reciprocating scan, line spacing 1.5mm, speed 180mm / s. Active crack control: During the spraying process, the substrate temperature is monitored in real time using an infrared thermometer and maintained at 220±10℃; the cooling rate is adjusted to 80-120℃ / s by adjusting the side-blown gas flow rate; laser shock peening is performed after every 3 spraying layers, with an energy density of 2J / cm² and a pulse width of 10ns for each laser shock peening.

[0025] Step S6. Prepare a microporous heat dissipation layer on the surface of the vertical crack functional layer: Use a spray gun to spray a dense transition layer on the surface of the vertical crack functional layer with a porosity of 15%-20%; the sprayed powder is porous YSZ nanoparticles; after the microporous heat dissipation layer is completed, a vertical crack heat insulation coating blank is formed on the surface of the substrate.

[0026] Step S7. Inducing crack depth propagation to the full thickness of the vertical crack functional layer: The vertical crack heat insulation coating blank is placed in a vacuum hot press furnace for heat treatment: First, hold at 1050℃ for 45 minutes; Second, rapidly cool from 1050℃ to room temperature within 30 minutes; Repeat steps one and two three times to induce crack depth propagation to the full thickness of the vertical crack functional layer.

[0027] Step S8. Laser Sealing: A fiber laser is used to laser seal the vertical crack insulation coating blank where the crack depth extends to the full thickness of the vertical crack functional layer. After sealing, a vertical crack insulation coating is formed on the surface of the substrate. The operating parameters of the fiber laser are: wavelength 1064nm, power 200W, scanning speed 500mm / s, and spot diameter 0.5mm. Laser sealing effectively preserves the internal vertical cracks and seals the micropores on the surface with a pore size of <5μm.

[0028] Further, in step S1, the sandblasting treatment uses white corundum sand with a particle size of 60 mesh, a pressure of 0.5 MPa, and a surface roughness Ra of 3.2-6.3 μm; the cleaning treatment uses ultrasonic cleaning with acetone solution at a frequency of 40 kHz for 15 min; the preheating treatment involves placing the sample in a vacuum furnace at 450°C and holding it there for 1 h.

[0029] The beneficial effects of this invention are as follows: Compared with the performance of traditional vertical crack coatings, this invention has the characteristics of long thermal cycle life, large thermal insulation temperature difference, strong oxidation resistance and low crack propagation rate; the microporous heat dissipation layer and the vertical crack form a synergistic heat dissipation channel, which improves the heat dissipation efficiency in the heat flow direction by 35%. Attached Figure Description

[0030] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort: Figure 1 This is a schematic diagram of the structure of the vertical crack heat insulation coating of the present invention applied to a high-temperature environment; Figure 2 This is a flowchart of the preparation method of the wear-resistant and corrosion-resistant roller of the present invention. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0032] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper surface," "lower surface," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "forward," "reverse," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] Example 1: Coating preparation for the nose cone of a hypersonic vehicle like Figure 1 As shown, a vertical crack heat insulation coating for use in high-temperature environments consists of the following layers from the substrate 1 to the surface: a metal bonding layer 2, a diffusion barrier layer 3, a dense transition layer 4, a vertical crack functional layer 5, and a microporous heat dissipation layer 6. The substrate 1 refers to the nose cone of a hypersonic aircraft.

[0034] The metal bonding layer 2 is prepared by low-pressure plasma spraying, with a surface roughness Ra ≤ 3.2 μm and a thickness of 28 μm. The material of the metal bonding layer is a Ni-Co-Cr-Al-Y-Ta alloy. The mass percentage of the Ni-Co-Cr-Al-Y-Ta alloy is: Ni: 65%, Co: 20%, Cr: 22%, Al: 12%, Y: 0.8%, Ta: 4%. This formulation can reduce the oxidation rate by 50% and increase the coating life by 3 times.

[0035] The diffusion barrier layer 3 is used to suppress element interdiffusion. The diffusion barrier layer is an Al2O3 / YSZ composite layer with a thickness of 6 μm. The diffusion barrier layer adopts a double-layer gradient structure: a dense Al2O3 layer with a thickness of 2 μm is located near the metal bonding layer; the side near the dense transition layer is a YSZ / Al2O3 mixed layer with a thickness of 4 μm. The YSZ / Al2O3 mixed layer uses nano-mixed powder with an Al2O3 content of 20 wt% and the remainder being YSZ.

[0036] The dense transition layer 4 is made of nanostructured YSZ, the thickness of the dense transition layer is 32μm, and the porosity of the dense transition layer is ≤3%.

[0037] The vertical crack functional layer 5 adopts a three-dimensional crack network structure with a crack density of 15 cracks / cm², a crack width of 1.2μm, and a crack depth that penetrates the functional layer. The thickness of the vertical crack functional layer is 82μm. The material is a rare earth-doped YSZ mixed nanoparticle, specifically a Gd2O3-YSZ mixed nanoparticle, with a Gd content of 8mol in the mixed nanoparticle.

[0038] The microporous heat dissipation layer 6 is a YSZ material layer with a porosity of 20% and a thickness of 22 μm. The YSZ material in the microporous heat dissipation layer is porous YSZ nanoparticles.

[0039] Example 2: This example describes the preparation of a coating for aero-engine turbine blades. A vertical crack heat insulation coating for use in high-temperature environments comprises, from the substrate to the surface layer: a metal bonding layer, a diffusion barrier layer, a dense transition layer, a vertical crack functional layer, and a microporous heat dissipation layer. The substrate is a DS-Ni based single crystal blade with dimensions of Φ120×20mm.

[0040] The metal bonding layer is prepared by low-pressure plasma spraying, with a surface roughness Ra ≤ 3.2 μm and a thickness of 22 μm. The material of the metal bonding layer is a Ni-Co-Cr-Al-Y-Ta alloy. The mass percentage of the Ni-Co-Cr-Al-Y-Ta alloy is: Ni: 65%, Co: 20%, Cr: 22%, Al: 12%, Y: 0.8%, Ta: 4%. This formulation can reduce the oxidation rate by 50% and increase the coating life by 3 times.

[0041] The diffusion barrier layer is used to suppress element interdiffusion. The diffusion barrier layer is an Al2O3 / YSZ composite layer with a thickness of 5 μm. The diffusion barrier layer adopts a double-layer gradient structure: a dense Al2O3 layer with a thickness of 2 μm is located near the metal binder layer; the side near the dense transition layer is a YSZ / Al2O3 mixed layer with a thickness of 3 μm. The YSZ / Al2O3 mixed layer uses nano-mixed powder with an Al2O3 content of 20 wt% and the balance being YSZ.

[0042] The dense transition layer is made of nanostructured YSZ, the thickness of the dense transition layer is 28 μm, and the porosity of the dense transition layer is ≤3%.

[0043] The vertical crack functional layer adopts a three-dimensional crack network structure with a crack density of 12-15 cracks / cm², a crack width of 0.8-1.2μm, and a crack depth that penetrates the functional layer. The thickness of the vertical crack functional layer is 78μm. The material is a rare earth-doped YSZ mixed nanoparticle, specifically a Gd₂O₃-YSZ mixed nanoparticle, with a Gd content of 6mol in the mixed nanoparticle.

[0044] The microporous heat dissipation layer is a YSZ material layer with a porosity of 15% and a thickness of 18 μm. The YSZ material in the microporous heat dissipation layer is porous YSZ nanoparticles.

[0045] like Figure 2As shown, a method for preparing a vertical crack heat-insulating coating for use in high-temperature environments includes the following steps: Step S1. The substrate is sandblasted, cleaned, and preheated. The sandblasting process uses white corundum sand with a particle size of 60 mesh, a pressure of 0.5 MPa, and a surface roughness of Ra 3.2-6.3 μm. The cleaning process uses ultrasonic cleaning with acetone solution at a frequency of 40 kHz for 15 min. The preheating process involves placing the substrate in a vacuum furnace at 450°C and holding it for 1 h. The substrate is a DS-Ni based single crystal blade with dimensions of Φ120×20 mm.

[0046] Step S2. Preparation of the metal bonding layer: The substrate is fed into a low-pressure plasma spraying system with a vacuum degree ≤10kPa. The equipment process parameters are: power: 32kW; spraying distance: 110mm; powder feeding rate: 25g / min; argon flow rate: 45L / min; hydrogen flow rate: 6L / min; spraying time: 45s. By precisely controlling the spraying time, the thickness of the metal bonding layer is controlled to achieve a thickness of 22μm.

[0047] Step S3. Prepare a diffusion barrier layer on the surface of the metal bonding layer: The diffusion barrier layer adopts a double-layer gradient structure. A 2μm thick dense Al2O3 layer is sprayed onto the surface of the metal bonding layer using a spray gun. The chemical inertness of Al2O3 isolates the diffusion of alloying elements. A 3μm thick YSZ / Al2O3 mixed layer is sprayed onto the surface of the dense Al2O3 layer. The YSZ / Al2O3 mixed layer is used to improve the interfacial wettability and bonding strength. The YSZ / Al2O3 mixed layer uses nano-mixed powder with an Al2O3 content of 20wt% and the balance being YSZ.

[0048] Step S4. Prepare a dense transition layer on the surface of the diffusion barrier layer: Use a spray gun to spray a 28μm thick dense transition layer on the surface of the diffusion barrier layer. The spray powder is nanostructured YSZ, and the porosity of the dense transition layer is ≤3%.

[0049] Step S5. Prepare a vertical crack functional layer on the surface of the dense transition layer: the thickness of the vertical crack functional layer is 78 μm. The vertical crack functional layer adopts a three-dimensional crack network structure with a crack density of 12-15 cracks / cm², a crack width of 0.8-1.2 μm, and a crack depth that penetrates the functional layer.

[0050] The spraying powder is made of rare earth-doped YSZ, specifically Gd2O3-YSZ, with a Gd content of 6-8 mol%. The spraying powder has a uniform particle size distribution, no agglomerated particles, and a particle size distribution range of D10=15μm, D50=25μm, D90=35μm. 0.5wt% Ni nanoparticles are added to the spraying powder as a crack inducing agent. Optimized spraying parameters: Power: 38kW (15% higher than conventional APS); Spraying distance: 130mm; Powder feed rate: 32g / min; Side-blowing cooling: Argon flow rate 25L / min, cooling distance 50mm; Scanning strategy: Reciprocating scan, line spacing 1.5mm, speed 180mm / s. Active crack control: During the spraying process, the substrate temperature is monitored in real time using an infrared thermometer and maintained at 220±10℃; the cooling rate is adjusted to 80-120℃ / s by adjusting the side-blown gas flow rate; laser shock peening is performed after every 3 spraying layers, with an energy density of 2J / cm² and a pulse width of 10ns for each laser shock peening.

[0051] Step S6. Prepare a microporous heat dissipation layer on the surface of the vertical crack functional layer: Use a spray gun to spray a 20μm thick dense transition layer with a porosity of 15%-20% on the surface of the vertical crack functional layer; the sprayed powder is porous YSZ nanoparticles; after the microporous heat dissipation layer is completed, a vertical crack heat insulation coating blank is formed on the surface of the substrate.

[0052] Step S7. Inducing crack depth propagation to the full thickness of the vertical crack functional layer: The vertical crack heat insulation coating blank is placed in a vacuum hot press furnace for heat treatment: First, hold at 1050℃ for 45 minutes; Second, rapidly cool from 1050℃ to room temperature within 30 minutes; Repeat steps one and two three times to induce crack depth propagation to the full thickness of the vertical crack functional layer.

[0053] Step S8. Laser Sealing: A fiber laser is used to laser seal the vertical crack insulation coating blank where the crack depth extends to the full thickness of the vertical crack functional layer. After sealing, a vertical crack insulation coating is formed on the surface of the substrate. The operating parameters of the fiber laser are: wavelength 1064nm, power 200W, scanning speed 500mm / s, and spot diameter 0.5mm. Laser sealing effectively preserves the internal vertical cracks and seals the micropores on the surface with a pore size of <5μm.

[0054] Key innovations of this application: First, the vertical crack functional layer adopts a three-dimensional crack network design with a crack density of 12-15 cracks / cm², a width of 0.8-1.2μm, and a depth that penetrates the functional layer. Second, the microporous heat dissipation layer and the vertical crack form a synergistic heat dissipation channel, which improves the heat dissipation efficiency in the heat flow direction by 35%. Third, the material of the vertical crack functional layer adopts a mixed method of rare earth doped YSZ to suppress phase transformation above 1400℃, and Gd³⁺ replaces Y³⁺ to stabilize the t' phase structure.

[0055] Application verification: Application tests on a certain type of aero-engine turbine blades show that: • The blade surface temperature decreased by 195°C; • Service life extended from 800 hours to 2200 hours; • The maintenance cycle has been extended from 300 takeoffs and landings to 800 takeoffs and landings.

[0056] The performance comparison between the present invention and traditional vertical crack coatings is shown in Table 1: Table 1 Performance indicators This invention technology Traditional vertical crack coating Increase Thermal cycle life (times) 1200 500 140% 1200℃ thermal insulation temperature difference 210℃ 160℃ 31.3% Crack propagation rate 0.08μm / cycle 0.5μm / cycle 84% Phase transition suppression at 1400℃ No phase transition Phase transition occurs - Antioxidant activity (h) 2000 800 150% As shown in Table 1 above, compared with the performance of traditional vertical crack coatings, the present invention has the characteristics of long thermal cycle life, large thermal insulation temperature difference, strong oxidation resistance and low crack propagation rate.

[0057] Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of those embodiments or examples, without contradiction. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A vertical crack heat-insulating coating for use in high-temperature environments, characterized in that, From the substrate to the surface layer, the structure consists of: a metal bonding layer, a diffusion barrier layer, a dense transition layer, a vertical crack functional layer, and a microporous heat dissipation layer. The metal bonding layer is made of a Ni-Co-Cr-Al-Y-Ta alloy. The diffusion barrier layer is used to suppress interdiffusion of elements. The dense transition layer is made of nanostructured YSZ. The vertical crack functional layer has a three-dimensional crack network structure with a crack density of 12-15 cracks / cm², a crack width of 0.8-1.2μm, and a crack depth that penetrates the functional layer. The material used is a mixture of Gd₂O₃ and YSZ nanoparticles. The microporous heat dissipation layer is a YSZ material layer with a porosity of 15%-20% and a thickness of 18-22μm.

2. The vertical crack heat-insulating coating applied in high-temperature environments according to claim 1, characterized in that: The thickness of the vertical crack functional layer is 78-82 μm, and the Gd content in the mixed nanoparticles is 6-8 mol.

3. The vertical crack heat-insulating coating applied in high-temperature environments according to claim 2, characterized in that: The metal bonding layer is prepared by low-pressure plasma spraying, with a surface roughness Ra≤3.2μm and a thickness of 22-28μm.

4. The vertical crack heat-insulating coating for use in high-temperature environments according to claim 3, characterized in that: The diffusion barrier layer is an Al2O3 / YSZ composite layer with a thickness of 4-6 μm.

5. The vertical crack heat-insulating coating for use in high-temperature environments according to claim 4, characterized in that: The diffusion barrier layer adopts a double-layer gradient structure. The side near the metal bonding layer is a dense Al2O3 layer with a thickness of 2μm; the side near the dense transition layer is a YSZ / Al2O3 mixed layer with a thickness of 3μm. The YSZ / Al2O3 mixed layer uses nano-mixed powder with an Al2O3 content of 20wt% and the balance being YSZ.

6. The vertical crack insulating coating for use in high-temperature environments according to claim 5, characterized in that: The thickness of the dense transition layer is 28-32 μm, and the porosity of the dense transition layer is ≤3%.

7. The vertical crack heat-insulating coating for use in high-temperature environments according to claim 6, characterized in that: The YSZ material in the microporous heat dissipation layer is porous YSZ nanoparticles.

8. The vertical crack heat-insulating coating for use in high-temperature environments according to claim 8, characterized in that: The mass percentages of the Ni-Co-Cr-Al-Y-Ta alloy are: Ni: 65%, Co: 20%, Cr: 22%, Al: 12%, Y: 0.8%, Ta: 4%.

9. A method for preparing a vertical crack heat-insulating coating as described in claim 8, characterized in that, Includes the following steps: Step S1. Sandblast, clean, and preheat the substrate; Step S2. Preparation of the metal bonding layer: The substrate is fed into a low-pressure plasma spraying system with a vacuum degree ≤10kPa. The equipment process parameters are: power: 32kW; spraying distance: 110mm; powder feeding rate: 25g / min; argon flow rate: 45L / min; hydrogen flow rate: 6L / min; spraying time: 45s. The thickness of the metal bonding layer is controlled by precisely controlling the spraying time. Step S3. Prepare a diffusion barrier layer on the surface of the metal bonding layer: The diffusion barrier layer adopts a double-layer gradient structure. A dense Al2O3 layer is sprayed onto the surface of the metal bonding layer using a spray gun, and the chemical inertness of Al2O3 isolates the diffusion of alloying elements. A YSZ / Al2O3 mixed layer is sprayed onto the surface of the dense Al2O3 layer. The YSZ / Al2O3 mixed layer is used to improve the interfacial wettability and bonding strength. The YSZ / Al2O3 mixed layer uses nano-mixed powder with an Al2O3 content of 20wt% and the balance being YSZ. Step S4. Prepare a dense transition layer on the surface of the diffusion barrier layer: Use a spray gun to spray a dense transition layer on the surface of the diffusion barrier layer. The spray powder is nanostructured YSZ, and the porosity of the dense transition layer is ≤3%. Step S5. Prepare a vertical crack functional layer on the surface of the dense transition layer: The vertical crack functional layer adopts a three-dimensional crack network structure with a crack density of 12-15 cracks / cm², a width of 0.8-1.2μm, and a crack depth that penetrates the functional layer; The spraying powder is made of rare earth-doped YSZ, specifically Gd2O3-YSZ, with a Gd content of 6-8 mol%. The spraying powder has a uniform particle size distribution, no agglomerated particles, and a particle size distribution range of D10=15μm, D50=25μm, D90=35μm. 0.5wt% Ni nanoparticles are added to the spraying powder as a crack inducing agent. Optimized spraying parameters: Power: 38kW (15% higher than conventional APS); Spraying distance: 130mm; Powder feed rate: 32g / min; Side-blowing cooling: Argon flow rate 25L / min, cooling distance 50mm; Scanning strategy: Reciprocating scan, line spacing 1.5mm, speed 180mm / s. Active crack control: During the spraying process, the substrate temperature is monitored in real time using an infrared thermometer and maintained at 220±10℃; the cooling rate is adjusted to 80-120℃ / s by adjusting the side-blown gas flow rate; laser shock strengthening is performed after every 3 spraying layers, with an energy density of 2J / cm² and a pulse width of 10ns for each laser shock strengthening. Step S6. Prepare a microporous heat dissipation layer on the surface of the vertical crack functional layer: Use a spray gun to spray a dense transition layer on the surface of the vertical crack functional layer with a porosity of 15%-20%; The powder used for spraying is porous YSZ nanoparticles; after the microporous heat dissipation layer is completed, a vertical crack heat insulation coating blank is formed on the surface of the substrate; Step S7. Inducing crack depth propagation to the full thickness of the vertical crack functional layer: The vertical crack heat insulation coating blank is placed in a vacuum hot press furnace for heat treatment: First, hold at 1050℃ for 45 minutes; Second, rapidly cool from 1050℃ to room temperature within 30 minutes; Repeat steps one and two three times to induce crack depth propagation to the full thickness of the vertical crack functional layer. Step S8. Laser Sealing: A fiber laser is used to laser seal the vertical crack insulation coating blank where the crack depth extends to the full thickness of the vertical crack functional layer. After sealing, a vertical crack insulation coating is formed on the surface of the substrate. The operating parameters of the fiber laser are: wavelength 1064nm, power 200W, scanning speed 500mm / s, and spot diameter 0.5mm. Laser sealing effectively preserves the internal vertical cracks and seals the micropores on the surface with a pore size of <5μm.

10. The method for preparing a vertical crack heat-insulating coating for use in high-temperature environments according to claim 9, characterized in that, In step S1, the sandblasting process uses white corundum sand with a particle size of 60 mesh, a pressure of 0.5 MPa, and a surface roughness Ra of 3.2-6.3 μm; the cleaning process uses ultrasonic cleaning with acetone solution at a frequency of 40 kHz for 15 min; the preheating process involves placing the sample in a vacuum furnace at 450°C and holding it there for 1 h.

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