Environmental Barrier - Infrared Stealth Coating and Its Preparation Method

Abstract

This application provides an environmental barrier-infrared stealth coating and its preparation method. The environmental barrier-infrared stealth coating includes a SiC-based ceramic substrate, an adhesive layer, an intermediate layer, and an infrared stealth layer stacked sequentially. At least one etched region is formed on the surface of the intermediate layer opposite to the infrared stealth layer. The infrared stealth layer comprises ceramic columnar crystals, ceramic particles, and columnar cavities between adjacent ceramic columnar crystals. The ceramic particles fill the etched region, and the ceramic columnar crystals are located in the unetched area of ​​the surface of the intermediate layer with the etched region. The columnar cavities are located above the ceramic particles. The environmental barrier-infrared stealth coating provided in this application exhibits excellent high-temperature corrosion resistance and infrared stealth performance.

Description

Technical Field

[0001] This application relates to the field of high-temperature protective coating technology, and in particular to an environmental barrier-infrared stealth coating and its preparation method. Background Technology

[0002] SiC f SiC ceramic matrix composites (CMCs) possess low density, excellent high-temperature mechanical properties, and good oxidation resistance, making them one of the main candidate materials for high-temperature structural components in next-generation aero-engines. At high temperatures, the SiC matrix surface oxidizes to form a protective SiO2 layer. However, under actual service conditions, water vapor in the high-temperature exhaust gas reacts with SiO2 to generate volatile Si(OH)4, which then degrades the SiC matrix. f SiC components degrade rapidly, leading to the development of environmental barrier coatings that can isolate moisture. Environmental barrier coatings applied to aero-engine exhaust nozzle components must not only withstand the corrosive effects of high-temperature moisture but also resist detection by infrared-guided weapons.

[0003] Currently, over 95% of the detection sources for mainstream infrared-guided weapons originate from the engine exhaust (exhaust nozzle components and plume). This is based on the Stefan-Boltzmann law (M=εσT). 4 As can be seen, increased service temperature leads to a sharp increase in the infrared radiation intensity of hot-end components, increasing the risk of thermal exposure. Developing a high-temperature coating on the surface of CMC ceramic-based components that simultaneously inhibits water vapor corrosion and achieves infrared stealth is crucial for improving the safety and combat effectiveness of aircraft. This reduces the impact of water vapor corrosion, improves service safety, extends service life, and lowers the probability of hot-end components being detected and identified by infrared detectors. Summary of the Invention

[0004] Based on this, this application provides an environmental barrier-infrared stealth coating and its preparation method to improve the high-temperature corrosion resistance and infrared stealth performance of SiC-based ceramic hot-end components.

[0005] The first aspect of this application provides an environmental barrier-infrared stealth coating, comprising a SiC-based ceramic substrate, an adhesive layer, an intermediate layer, and an infrared stealth layer stacked sequentially; the intermediate layer has at least one etched region on its surface adjacent to the infrared stealth layer; the infrared stealth layer includes ceramic columnar crystals, ceramic particles, and columnar cavities between two adjacent ceramic columnar crystals; the ceramic particles fill the etched region; the ceramic columnar crystals are located in the unetched area of ​​the surface of the intermediate layer having the etched region; and the columnar cavities are located above the ceramic particles.

[0006] In some embodiments, the infrared stealth layer has at least one of the following features (1)-(4):

[0007] (1) The material of the infrared stealth layer includes one or more of rare earth zirconates and rare earth hafnium salts;

[0008] (2) The width of the ceramic columnar crystals is 10μm-40μm;

[0009] (3) The thickness of the infrared stealth layer is 100μm-150μm;

[0010] (4) The average particle size of the ceramic particles is 0.5μm-10μm;

[0011] (5) The volume percentage of the ceramic columnar crystals in the infrared stealth layer is 40%-80%;

[0012] (6) The ceramic particles account for 5%-30% of the volume of the infrared stealth layer;

[0013] (7) The columnar cavity accounts for 10%-40% of the volume of the infrared stealth layer;

[0014] (8) The columnar cavity penetrates the infrared stealth layer along the thickness direction of the infrared stealth layer, and the width of the columnar cavity is 8μm~15μm.

[0015] In some embodiments, the intermediate layer has at least one of the following features (1)-(4):

[0016] (1) The depth of the etched area is 5μm-50μm, the width of the etched area is 10μm-30μm, and the distance between two adjacent etched areas is 20μm-200μm;

[0017] (2) The thickness of the intermediate layer is 80μm-150μm;

[0018] (3) The material of the intermediate layer includes one or both of ytterbium silicate and ytterbium pyrosilicate;

[0019] (4) The porosity of the intermediate layer is <10%.

[0020] In some embodiments, the adhesive layer has at least one of the following features (1)-(2):

[0021] (1) The thickness of the adhesive layer is 60μm-125μm;

[0022] (2) The material of the adhesive layer includes Si.

[0023] In some embodiments, the SiC-based ceramic matrix is ​​selected from silicon carbide matrix or silicon carbide fiber-reinforced silicon carbide ceramic matrix composite matrix.

[0024] The second aspect of this application provides a method for preparing an environmental barrier-infrared stealth coating, comprising the following steps:

[0025] At least one surface of the SiC-based ceramic substrate is pretreated by sandblasting.

[0026] An adhesive layer is formed on the surface of the SiC-based ceramic substrate after sandblasting pretreatment, and an intermediate layer is formed on the surface of the adhesive layer that is relatively far away from the SiC-based ceramic substrate.

[0027] The intermediate layer is etched to form at least one etched area on the surface of the intermediate layer that is relatively far from the adhesive layer;

[0028] An infrared stealth layer is formed on the surface of the intermediate layer having the etched area. The infrared stealth layer includes ceramic columnar crystals, ceramic particles, and columnar cavities between two adjacent ceramic columnar crystals. The ceramic particles fill the etched area. The ceramic columnar crystals are located in the unetched area of ​​the surface of the intermediate layer having the etched area. The columnar cavities are located above the ceramic particles.

[0029] In some embodiments, the method for preparing the adhesive layer includes atmospheric plasma spraying.

[0030] In some embodiments, the method for preparing the adhesive layer includes at least one of the following conditions (1)-(6):

[0031] (1) The spraying current of the atmospheric plasma spraying is 500A-700A;

[0032] (2) The spraying power of the atmospheric plasma spraying is 35KW-40KW;

[0033] (3) The gas used in the atmospheric plasma spraying includes argon, and the argon flow rate is 30 slpm-40 slpm;

[0034] (4) The gas used in the atmospheric plasma spraying includes hydrogen, and the hydrogen flow rate is 5 slpm-8 slpm;

[0035] (5) The powder feeding rate of the atmospheric plasma spraying is 25g / min-35g / min;

[0036] (6) The spraying distance of the atmospheric plasma spraying is 80mm-100mm.

[0037] In some embodiments, the method for preparing the intermediate layer includes atmospheric plasma spraying.

[0038] In some embodiments, the method for preparing the intermediate layer includes at least one of the following conditions (1)-(6):

[0039] (1) The spraying current of the atmospheric plasma spraying is 500A-700A;

[0040] (2) The spraying power of the atmospheric plasma spraying is 40KW-45KW;

[0041] (3) The gas used in the atmospheric plasma spraying includes argon, and the argon flow rate is 30 slpm-40 slpm;

[0042] (4) The gas used in the atmospheric plasma spraying includes hydrogen, and the hydrogen flow rate is 8 slpm-12 slpm;

[0043] (5) The powder feeding rate of the atmospheric plasma spraying is 25g / min-35g / min;

[0044] (6) The spraying distance of the atmospheric plasma spraying is 80mm-100mm.

[0045] In some embodiments, the intermediate layer is prepared by plasma physical vapor deposition.

[0046] In some embodiments, the method for preparing the intermediate layer includes at least one of the following conditions (1)-(5):

[0047] (1) The deposition current of the plasma physical vapor deposition is 1100A-1200A;

[0048] (2) The deposition power of the plasma physical vapor deposition is 30KW-40KW;

[0049] (3) The plasma gas used in the plasma physical vapor deposition includes argon and helium, with the argon flow rate being 20 slpm-40 slpm and the helium flow rate being 30 slpm-60 slpm.

[0050] (4) The powder feeding rate of the plasma physical vapor deposition is 8 g / min-10 g / min;

[0051] (5) The spraying distance of the plasma physical vapor deposition is 600mm-800mm.

[0052] In some embodiments, the intermediate layer is etched using a pulsed laser.

[0053] In some embodiments, the etching process includes at least one of the following conditions (1)-(7):

[0054] (1) The center wavelength of the laser in the pulsed laser is 355nm;

[0055] (2) The laser focusing spot diameter of the pulsed laser is 10μm-20μm;

[0056] (3) The pulse width of the laser in the pulsed laser is 10ns-20ns;

[0057] (4) The laser power of the pulsed laser is 3W-10W;

[0058] (5) The repetition frequency of the pulsed laser is 10kHz-30kHz;

[0059] (6) The scanning speed of the pulsed laser is 50 mm / s-200 mm / s;

[0060] (7) The number of times the pulsed laser scan is repeated is 1 to 5 times.

[0061] In some embodiments, the method for preparing the infrared stealth layer includes plasma physical vapor deposition.

[0062] In some embodiments, the method for preparing the infrared stealth layer includes at least one of the following conditions (1)-(7):

[0063] (1) The vacuum degree of the plasma physical vapor deposition is 1 mbar-5 mbar;

[0064] (2) The working gases used in the plasma physical vapor deposition include argon and helium, with the argon flow rate being 20 slpm-40 slpm and the helium flow rate being 30 slpm-60 slpm.

[0065] (3) The spray gun distance for the plasma physical vapor deposition is 800mm-1200mm;

[0066] (4) The deposition current of the plasma physical vapor deposition is 1800A-2100A;

[0067] (5) The deposition power of the plasma physical vapor deposition is 55kW-65kW;

[0068] (6) The powder feeding rate of the plasma physical vapor deposition is 8 g / min-10 g / min;

[0069] (7) The sample preheating temperature for plasma physical vapor deposition is 600℃-800℃.

[0070] In the aforementioned environmental barrier-infrared stealth coating, the adhesive layer rapidly oxidizes under high-temperature service conditions, generating a protective SiO2 oxide film to prevent corrosion of the SiC-based ceramic substrate. The dense intermediate layer inhibits the contact and reaction between high-temperature moisture and the SiO2 oxide film, reducing the generation and volatilization rate of Si(OH)4. The combined effect of the adhesive layer and the intermediate layer prevents performance degradation of the SiC-based ceramic substrate. The infrared stealth layer, on the one hand, achieves diffraction extinction of its own infrared radiation through columnar cavities, reducing infrared emissivity; on the other hand, it provides thermal insulation through low thermal conductivity ceramic columnar crystals and ceramic particles, reducing surface temperature. Both work together to reduce the infrared radiation intensity of the component, achieving infrared stealth. Therefore, the environmental barrier-infrared stealth coating provided in this application possesses excellent high-temperature corrosion resistance and infrared stealth performance.

[0071] The aforementioned method for preparing an environmental barrier-infrared stealth coating involves etching the intermediate layer, during which the etched area is laser-remelted and solidified to form a dense structure, further enhancing the intermediate layer's density and resistance to water vapor corrosion. The etched areas on the intermediate layer surface induce the aggregation of ceramic particles during the infrared stealth layer deposition process, resulting in a higher concentration of ceramic particles within the etched area and the formation of columnar cavities above these particles. This allows for the one-step formation of a micro / nano composite structure comprising ceramic columnar crystals, ceramic particles, and columnar cavities. Simultaneously, the columnar cavities improve the strain tolerance of the infrared stealth layer, reduce the probability of interfacial failure due to the mismatch in thermal expansion coefficients between the infrared stealth layer and the intermediate layer, extend the coating's lifespan, and broaden the range of suitable infrared stealth layer materials. Furthermore, this preparation method is highly efficient, reproducible, and offers flexible and controllable process parameters. Attached Figure Description

[0072] To more clearly illustrate the technical solutions in the embodiments of this application and to more completely understand this application and its beneficial effects, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0073] Figure 1 A schematic diagram of the structure of an environmental barrier-infrared stealth coating provided in one embodiment;

[0074] Figure 2 Electron backscattering diffraction patterns of the coating sections obtained in Examples 1, 2 and Comparative Example 1;

[0075] Figure 3 Examples 1, 2, Comparative Example 1, and 3 (SiC) show the coatings prepared by SiC and the infrared emissivity of SiC in the 3μm~5μm wavelength band at different temperatures. Figure 3 (a) and Figure 3 (b) shows the results at 800℃ and 1100℃, respectively. Detailed Implementation

[0076] To facilitate understanding of the present invention, a more complete description of this application will be provided below with reference to relevant embodiments. Preferred embodiments of the present application are given below. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the disclosure of this application will be achieved.

[0077] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0078] As used herein, the terms "and / or," "or / and," and "and / or" encompass any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected using at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that, in this application, the technical solution undoubtedly includes solutions connected by "logical AND," and also undoubtedly includes solutions connected by "logical OR."

[0079] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0080] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0081] This document only specifically discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form an unspecified range.

[0082] Unless otherwise specified, the temperature parameters in this application may be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows temperature fluctuations within the precision range controlled by the instrument, such as ±5°C, ±4°C, ±3°C, ±2°C, or ±1°C.

[0083] In this application, unless otherwise specified, the terms "size," "particle size," and "diameter" generally refer to average values. In this application, "particle size" and "particle diameter" have the same definition, both representing the average particle size of spheres or spheroids.

[0084] In this document, the term "suitable" as used in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0085] In this application, terms such as "further," "even further," and "particularly" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0086] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0087] In the description of the application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0088] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions. Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical solutions.

[0089] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, but sequentially is preferred.

[0090] Preparing high-temperature coatings on the surface of CMC ceramic-based components, which simultaneously inhibit water vapor corrosion and achieve infrared stealth effects, is crucial for improving aircraft safety and combat effectiveness. This reduces the impact of water vapor corrosion, improves service safety, extends service life, and lowers the probability of hot-end components being detected and identified by infrared detectors. Reducing infrared radiation intensity can be achieved by lowering the surface emissivity (ε) or surface temperature (T). Noble metals have extremely low emissivity; coatings with noble metals or ceramic coatings filled with noble metal particles can significantly reduce the radiation intensity of components. Chinese patent application CN110002900A discloses a composite coating prepared on a CMC substrate using Bi2O3-ZnO glass containing noble metal fillers as a low-emissivity layer and a mullite / BSAS composite system as an antioxidant layer. The emissivity at 900℃ can be as low as 0.14, and it exhibits good high-temperature resistance and thermal shock resistance. Chinese patent application CN111732457A discloses a coating using precious metal Pt powder as a filler to reduce the infrared emissivity of the coating.

[0091] However, due to the weak interfacial van der Waals forces between the metallic filler and the non-metallic coating material, and the significant difference in their coefficients of thermal expansion, the metal-non-metal interface is prone to cracking under high-temperature conditions, leading to overall coating failure. Furthermore, when the metallic thin film is used as a low-emissivity surface layer, it is easily damaged by the high-speed scouring environment of the combustion chamber, resulting in decreased coating performance and shortened lifespan. Moreover, the melting point of metallic materials limits their use at higher temperatures. Therefore, there is an urgent need to develop environmental barrier-infrared stealth coatings suitable for higher service temperatures and more demanding service environments.

[0092] One or more embodiments of this application provide an environmental barrier-infrared stealth coating, comprising a SiC-based ceramic substrate, an adhesive layer, an intermediate layer, and an infrared stealth layer stacked sequentially; the intermediate layer has at least one etched area on one side surface relative to the infrared stealth layer; the infrared stealth layer includes ceramic columnar crystals, ceramic particles, and columnar cavities between two adjacent ceramic columnar crystals; the ceramic particles fill the etched area; the ceramic columnar crystals are located in the unetched area of ​​the surface of the intermediate layer with the etched area; and the columnar cavities are located above the ceramic particles.

[0093] It should be noted that when multiple etched areas are set on the surface of the intermediate layer relative to the infrared stealth layer, the shape and arrangement of the etched areas can be a periodic grid structure.

[0094] Understandably, in the aforementioned environmental barrier-infrared stealth coating, the adhesive layer rapidly oxidizes under high-temperature service conditions, generating a protective SiO2 oxide film to prevent corrosion of the SiC-based ceramic substrate. The dense intermediate layer inhibits the contact and reaction between high-temperature moisture and the SiO2 oxide film, reducing the generation and volatilization rate of Si(OH)4. The combined effect of the adhesive layer and the intermediate layer prevents performance degradation of the SiC-based ceramic substrate. The infrared stealth layer, on the one hand, achieves diffraction extinction of its own infrared radiation through columnar cavities, reducing infrared emissivity; on the other hand, it achieves thermal insulation through low thermal conductivity ceramic columnar crystals and ceramic particles, reducing surface temperature. The combined effect of these two factors reduces the infrared radiation intensity of the component, achieving infrared stealth. Therefore, the environmental barrier-infrared stealth coating provided in this application possesses excellent high-temperature corrosion resistance and infrared stealth performance.

[0095] like Figure 1 As shown, as a non-limiting example, the environmental barrier-infrared stealth coating includes a SiC-based ceramic substrate 1, an adhesive layer 2, an intermediate layer 3, and an infrared stealth layer 4 stacked sequentially; the intermediate layer 3 has at least one etched region 31 on the side surface opposite to the infrared stealth layer 4; the infrared stealth layer 4 includes ceramic columnar crystals 41, ceramic particles 42, and columnar cavities 43 between two adjacent ceramic columnar crystals; the ceramic particles 42 fill the etched region 31; the ceramic columnar crystals 41 are located in the unetched area of ​​the surface of the intermediate layer 3 with the etched region 31; and the columnar cavities 43 are located above the ceramic particles 42.

[0096] In some embodiments, the infrared stealth layer material includes one or more of rare earth zirconates and rare earth hafnium salts. Optionally, the rare earth zirconates include (Gd... 0.9 Yb 0.1 )2Zr2O7.

[0097] As one possible implementation, the width of the ceramic columnar crystals is 10μm-40μm; for example, it can be, but is not limited to, 10μm, 12μm, 14μm, 16μm, 18μm, 20μm, 22μm, 24μm, 26μm, 28μm, 30μm, 32μm, 34μm, 36μm, 38μm, 40μm, or any range between two of the above widths. Therefore, the ceramic columnar crystals have good strain tolerance, which is beneficial for improving the high-temperature service life of the infrared stealth layer.

[0098] It is understandable that the “width of the ceramic columnar crystal” mentioned in the context refers to the maximum radial length of each ceramic columnar crystal.

[0099] In some optional embodiments, the thickness of the infrared stealth layer is 100μm-150μm; for example, it can be, but is not limited to, 100μm, 105μm, 110μm, 115μm, 120μm, 125μm, 130μm, 135μm, 140μm, 145μm, 150μm, or any range between two of the above thicknesses. When the thickness of the infrared stealth layer is within the above range, it has a significant heat insulation effect and can significantly reduce the surface temperature of the component. Optionally, the thickness of the infrared stealth layer is 110μm-120μm.

[0100] In some embodiments, the average particle size of the ceramic particles is 0.5 μm-10 μm; for example, it can be, but is not limited to, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, or any range between two of the above particle sizes. Therefore, it has a certain heat insulation effect.

[0101] In some alternative embodiments, the average particle size of the ceramic particles is 5 μm-9 μm.

[0102] In some exemplary embodiments, the volume fraction of ceramic columnar crystals in the infrared stealth layer is 40%-80%; for example, it can be, but is not limited to, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or any range between two of the above volume fractions. Therefore, the infrared stealth layer has low infrared emissivity, good thermal insulation performance, and strain tolerance.

[0103] As one possible implementation, the volumetric proportion of ceramic columnar crystals in the infrared stealth layer is 65%-80%.

[0104] In some embodiments, the volume percentage of ceramic particles in the infrared stealth layer is 5%-30%; for example, it can be, but is not limited to, 5%, 10%, 15%, 20%, 25%, 30%, or any range between two of the above volume percentages. Therefore, the infrared stealth layer has low infrared emissivity and good thermal insulation performance.

[0105] In some implementations, the ceramic particles account for 5%-18% of the volume of the infrared stealth layer.

[0106] In some embodiments, the columnar cavity accounts for 10%-40% of the volume of the infrared stealth layer; for example, it can be, but is not limited to, 10%, 15%, 20%, 25%, 30%, 35%, 40%, or any range between two of the above volume percentages. Therefore, the infrared stealth layer has low infrared emissivity, good thermal insulation performance, and strain tolerance.

[0107] In some alternative implementations, the columnar cavity accounts for 15%-25% of the volume of the infrared stealth layer.

[0108] As one possible implementation, the columnar cavity penetrates the infrared stealth layer along its thickness direction, and the width of the columnar cavity is 8μm-15μm; for example, it can be, but is not limited to, 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, or any two of the above particle sizes. When the width of the columnar cavity is within the above range, it is beneficial for the infrared stealth layer to reduce infrared radiation through diffraction extinction while maintaining high heat insulation capability, thereby reducing the infrared radiation intensity on the surface of the component by reducing emissivity and lowering temperature.

[0109] In some alternative implementations, the width of the cylindrical cavity is 12 μm-15 μm.

[0110] It should be noted that the “width of the cylindrical cavity” mentioned in the context refers to the longest straight-line distance between two points on the edge of the cylindrical cavity on a plane perpendicular to the thickness direction of the infrared stealth layer.

[0111] In some exemplary embodiments, the depth of the etched region is 5μm-50μm; for example, it can be, but is not limited to, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, or any range between two of the above depths. Optionally, the depth of the etched region is 30μm-50μm.

[0112] As one possible implementation, the width of the etched area is 10μm-30μm, for example, but not limited to 10μm, 15μm, 20μm, 25μm, 30μm or any range between the two widths mentioned above.

[0113] In some optional embodiments, the spacing between two adjacent etched regions is 20μm-200μm; for example, it can be, but is not limited to, 20μm, 40μm, 60μm, 80μm, 100μm, 120μm, 140μm, 160μm, 180μm, 200μm, or any range between two of the above spacings. Optionally, the spacing between two adjacent etched regions is 50μm-110μm.

[0114] When the depth, width, and spacing of the etched area are within the above-mentioned ranges, it is beneficial for the ceramic columnar crystals, ceramic particles, and columnar cavities of the infrared stealth layer to be within a suitable range.

[0115] It should be noted that the depth of the etched area mentioned in the context refers to the distance etched downwards from the surface of the intermediate layer relatively close to the low infrared reflectivity layer in a direction perpendicular to that surface to the deepest point; the width of the etched area refers to the longest straight-line length of the etched area in a direction parallel to the surface of the intermediate layer. The spacing between two adjacent etched areas refers to the shortest straight-line distance between the edges of two adjacent etched areas on the surface of the intermediate layer.

[0116] In some embodiments, the thickness of the intermediate layer is 80 μm-150 μm; for example, it can be, but is not limited to, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, 150 μm, or any range between two of the above thicknesses. When the thickness of the intermediate layer is within the above range, the intermediate layer exhibits excellent resistance to water vapor corrosion and good strain tolerance.

[0117] In some alternative implementations, the thickness of the intermediate layer is 90 μm-145 μm.

[0118] As one possible implementation, the material of the intermediate layer includes one or both of ytterbium silicate (Yb2SiO5, YbMS) and ytterbium pyrosilicate (Yb2Si2O7, YbDS).

[0119] In some alternative embodiments, the intermediate layer has a dense structure. Optionally, the porosity of the intermediate layer is <10%. Therefore, the intermediate layer exhibits excellent resistance to water vapor corrosion.

[0120] As one possible implementation, the thickness of the adhesive layer is 60μm-125μm; for example, it can be, but is not limited to, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm, 115μm, 120μm, 125μm, or any range between two of the above thicknesses. Therefore, the adhesive layer has excellent strain tolerance, and the environmental barrier-infrared stealth coating has excellent high-temperature long-term service life. Optionally, the thickness of the adhesive layer is 80μm-125μm.

[0121] In some alternative embodiments, the adhesive layer is made of Si.

[0122] In some embodiments, the SiC-based ceramic matrix is ​​selected from a silicon carbide matrix or a silicon carbide fiber-reinforced silicon carbide ceramic matrix composite matrix.

[0123] One or more embodiments of this application provide a method for preparing an environmental barrier-infrared stealth coating, comprising the following steps:

[0124] At least one surface of a SiC-based ceramic substrate is pre-treated by sandblasting; an adhesive layer is formed on the surface of the pre-treated SiC-based ceramic substrate, and an intermediate layer is formed on the surface of the adhesive layer relatively far from the SiC-based ceramic substrate; the intermediate layer is etched to form at least one etched area on the surface of the intermediate layer relatively far from the adhesive layer; an infrared stealth layer is formed on the surface of the intermediate layer with the etched area, the infrared stealth layer comprising ceramic columnar crystals, ceramic particles, and columnar cavities between two adjacent ceramic columnar crystals, the ceramic particles filling the etched area, the ceramic columnar crystals located in the unetched area of ​​the surface of the intermediate layer with the etched area, and the columnar cavities located above the ceramic particles.

[0125] Understandably, the method for preparing the environmental barrier-infrared stealth coating provided in this application involves etching the intermediate layer, during which the etched area is laser-remelted and solidified to form a dense structure, further improving the density and resistance to water vapor corrosion of the intermediate layer. The etched area on the surface of the intermediate layer can induce the aggregation of ceramic particles during the deposition of the infrared stealth layer, resulting in a larger number of ceramic particles within the etched area and the formation of columnar cavities above the ceramic particles. This allows for the one-step formation of a micro / nano composite structure containing ceramic columnar crystals, ceramic particles, and columnar cavities. Simultaneously, the columnar cavities can improve the strain tolerance of the infrared stealth layer, reduce the probability of interface failure due to the mismatch in thermal expansion coefficients between the infrared stealth layer and the intermediate layer, extend the coating's service life, and expand the range of selectable infrared stealth layer materials. Furthermore, this preparation method is highly efficient, reproducible, and offers flexible and controllable process parameters.

[0126] In some embodiments, the method for preparing the adhesive layer includes atmospheric plasma spraying.

[0127] As one possible implementation, when preparing the adhesive layer, the spraying current of atmospheric plasma spraying is 500A-700A; for example, it can be, but is not limited to, 500A, 520A, 540A, 560A, 580A, 600A, 620A, 640A, 660A, 680A, 700A, or any range between two of the above spraying currents.

[0128] In some optional embodiments, when preparing the adhesive layer, the spraying power of atmospheric plasma spraying is 35KW-40KW; for example, it can be, but is not limited to, 35KW, 36KW, 37KW, 38KW, 39KW, 40KW or any range between the above two power values.

[0129] In some embodiments, the gas used in atmospheric plasma spraying for preparing the adhesive layer includes argon. Further optionally, the argon flow rate is 30 slpm-40 slpm; for example, it can be, but is not limited to, 30 slpm, 32 slpm, 34 slpm, 36 slpm, 38 slpm, 40 slpm, or any range between two of the above flow rates.

[0130] In some exemplary embodiments, the gas used in atmospheric plasma spraying for preparing the adhesive layer includes hydrogen. As a non-limiting example, the hydrogen flow rate is 5 slpm to 8 slpm; for example, it can be, but is not limited to, 5 slpm, 6 slpm, 7 slpm, 8 slpm, or any range between two of the above flow rates.

[0131] In some embodiments, when preparing the adhesive layer, the powder feed rate of atmospheric plasma spraying is 25 g / min to 35 g / min; for example, it can be, but is not limited to, 25 g / min, 26 g / min, 27 g / min, 28 g / min, 29 g / min, 30 g / min, 31 g / min, 32 g / min, 33 g / min, 34 g / min, 35 g / min, or any range between two of the above powder feed rates.

[0132] In some optional embodiments, when preparing the adhesive layer, the spraying distance of atmospheric plasma spraying is 80mm-100mm; for example, it can be, but is not limited to, 80mm, 82mm, 84mm, 84mm, 86mm, 88mm, 90mm, 92mm, 94mm, 96mm, 98mm, 100mm or any range between two of the above distances.

[0133] In some embodiments, the intermediate layer is prepared by atmospheric plasma spraying.

[0134] In some optional embodiments, when preparing the intermediate layer, the spraying current of atmospheric plasma spraying is 500A-700A; for example, it can be, but is not limited to, 500A, 520A, 540A, 560A, 580A, 600A, 620A, 640A, 660A, 680A, 700A, or any range between two of the above spraying currents.

[0135] In some optional embodiments, when preparing the intermediate layer, the spraying power of atmospheric plasma spraying is 40KW-45KW; for example, it can be, but is not limited to, 40KW, 41KW, 42KW, 43KW, 44KW, 45KW or any range between the above two power values.

[0136] In some embodiments, the gas used for atmospheric plasma spraying during the preparation of the intermediate layer includes argon. Further optionally, the argon flow rate is 30 slpm-40 slpm; for example, it can be, but is not limited to, 30 slpm, 32 slpm, 34 slpm, 36 slpm, 38 slpm, 40 slpm, or any range between two of the above flow rates.

[0137] In some exemplary embodiments, the gas used for atmospheric plasma spraying during the preparation of the intermediate layer includes hydrogen. As a non-limiting example, the hydrogen flow rate is 8 slpm-12 slpm; for example, it can be, but is not limited to, 8 slpm, 9 slpm, 10 slpm, 11 slpm, 12 slpm, or any range between two of the above flow rates.

[0138] In some optional embodiments, when preparing the intermediate layer, the powder feed rate of atmospheric plasma spraying is 25 g / min to 35 g / min; for example, it can be, but is not limited to, 25 g / min, 26 g / min, 27 g / min, 28 g / min, 29 g / min, 30 g / min, 31 g / min, 32 g / min, 33 g / min, 34 g / min, 35 g / min or any range between two of the above powder feed rates.

[0139] In some embodiments, when preparing the intermediate layer, the spraying distance of atmospheric plasma spraying is 80mm-100mm; for example, it can be, but is not limited to, 80mm, 82mm, 84mm, 84mm, 86mm, 88mm, 90mm, 92mm, 94mm, 96mm, 98mm, 100mm or any range between two of the above distances.

[0140] In some embodiments, the intermediate layer is prepared by plasma physical vapor deposition.

[0141] In some alternative embodiments, when preparing the intermediate layer, the deposition current of plasma physical vapor deposition is 1100A-1200A; for example, it can be, but is not limited to, 1100A, 1120A, 1140A, 1160A, 1180A, 1200A or any range between two of the above currents.

[0142] In some embodiments, when preparing the intermediate layer, the deposition power of plasma physical vapor deposition is 30KW-40KW; for example, it can be, but is not limited to, 30KW, 31KW, 32KW, 33KW, 34KW, 35KW, 36KW, 37KW, 38KW, 39KW, 40KW, or any range between the two of the above power values.

[0143] In some optional embodiments, the plasma gas used in plasma physical vapor deposition for preparing the intermediate layer includes argon and helium. Optionally, the argon flow rate is 20 slpm-40 slpm; for example, it can be, but is not limited to, 20 slpm, 25 slpm, 30 slpm, 35 slpm, 40 slpm, or any range between two of the above flow rates. Optionally, the helium flow rate is 30 slpm-60 slpm; for example, it can be, but is not limited to, 30 slpm, 35 slpm, 40 slpm, 45 slpm, 50 slpm, 55 slpm, 60 slpm, or any range between two of the above flow rates.

[0144] In some exemplary embodiments, when preparing the intermediate layer, the powder feed rate of plasma physical vapor deposition is 8 g / min to 10 g / min; for example, it can be, but is not limited to, 8 g / min, 9 g / min, 10 g / min or any range between the two powder feed rates mentioned above.

[0145] As one possible implementation, when preparing the intermediate layer, the spraying distance of plasma physical vapor deposition is 600mm-800mm; for example, it can be, but is not limited to, 600mm, 620mm, 640mm, 660mm, 680mm, 700mm, 720mm, 740mm, 760mm, 780mm, 800mm, or any range between two of the above distances.

[0146] In some implementations, pulsed lasers are used to etch the intermediate layer.

[0147] In some alternative implementations, the center wavelength of the pulsed laser is 355 nm during the etching process.

[0148] In some of these embodiments, the laser spot diameter of the pulsed laser is 10μm-20μm during the etching process; for example, it can be, but is not limited to, 10μm, 12μm, 14μm, 16μm, 18μm, 20μm or the distance between any two of the above diameters.

[0149] In some exemplary embodiments, when performing the etching process, the pulse width of the pulsed laser is 10ns-20ns; for example, it can be, but is not limited to, 10ns, 12ns, 14ns, 16ns, 18ns, 20ns or any range between two of the above pulse widths.

[0150] As one possible implementation, the laser power of the pulsed laser during the etching process is 3W-10W; for example, it can be, but is not limited to, 3W, 4W, 5W, 6W, 7W, 8W, 9W, 10W or any two of the above power ranges.

[0151] In some alternative implementations, the repetition frequency of the pulsed laser during the etching process is 10kHz-30kHz; for example, it can be, but is not limited to, 10kHz, 12kHz, 14kHz, 16kHz, 18kHz, 20kHz, 22kHz, 24kHz, 26kHz, 28kHz, 30kHz, or any range between two of the above frequencies.

[0152] As one possible implementation, the scanning speed of the pulsed laser during the etching process is 50 mm / s to 200 mm / s; for example, it can be, but is not limited to, 50 mm / s, 70 mm / s, 90 mm / s, 100 mm / s, 120 mm / s, 140 mm / s, 160 mm / s, 180 mm / s, 200 mm / s, or any range between two of the above speeds.

[0153] In some alternative implementations, the number of times the pulsed laser scans are repeated during the etching process is 1 to 5 times; for example, it can be, but is not limited to, 1, 2, 3, 4, 5 times or any range between the above two values.

[0154] In some embodiments, the infrared stealth layer is prepared by plasma physical vapor deposition.

[0155] In some alternative implementations, the vacuum level of plasma physical vapor deposition is 1 mbar to 5 mbar when preparing the infrared stealth layer; for example, it can be, but is not limited to, 1 mbar, 2 mbar, 3 mbar, 4 mbar, 5 mbar or any range between the two vacuum levels mentioned above.

[0156] In some embodiments, the working gas used in plasma physical vapor deposition for fabricating the infrared stealth layer includes argon and helium. Optionally, the argon flow rate is 20 slpm-40 slpm; for example, it can be, but is not limited to, 20 slpm, 25 slpm, 30 slpm, 35 slpm, 40 slpm, or any range between two of the above flow rates. Optionally, the helium flow rate is 30 slpm-60 slpm; for example, it can be, but is not limited to, 30 slpm, 35 slpm, 40 slpm, 45 slpm, 50 slpm, 55 slpm, 60 slpm, or any range between two of the above flow rates.

[0157] In some optional embodiments, when preparing the infrared stealth layer, the spray gun distance for plasma physical vapor deposition is 800mm-1200mm; for example, it can be, but is not limited to, 800mm, 900mm, 1000mm, 1100mm, 1200mm or any range between two of the above distances.

[0158] In some embodiments, when preparing the infrared stealth layer, the deposition current of plasma physical vapor deposition is 1800A-2100A; for example, it can be, but is not limited to, 1800A, 1850A, 1900A, 1950A, 2000A, 2050A, 2100A or any range between the above two currents.

[0159] As one possible implementation, when preparing the infrared stealth layer, the deposition power of plasma physical vapor deposition is 55kW-65kW; for example, it can be, but is not limited to, 55kW, 56kW, 57kW, 58kW, 59kW, 60kW, 61kW, 62kW, 63kW, 64kW, 65kW, or any range between the two of the above power values.

[0160] In some alternative embodiments, when preparing the infrared stealth layer, the powder feed rate of plasma physical vapor deposition is 8 g / min to 10 g / min; for example, it can be, but is not limited to, 8 g / min, 9 g / min, 10 g / min or any range between the two powder feed rates mentioned above.

[0161] As a non-limiting example, when preparing the infrared stealth layer, the sample preheating temperature for plasma physical vapor deposition is 600℃-800℃; for example, it can be, but is not limited to, 600℃, 620℃, 640℃, 660℃, 680℃, 700℃, 720℃, 740℃, 760℃, 780℃, 800℃, or any range between two of the above temperatures.

[0162] The technical solution of the present invention will be described in detail below with reference to specific embodiments. It should be understood that these embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this invention, or follow experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0163] Example 1

[0164] S1: Select size 10×10×5mm 3 SiC ceramic was used as the substrate, and the SiC ceramic substrate was pretreated by sandblasting. The sandblasting pressure was 5MPa and the sandblasting time was 120 seconds.

[0165] S2: An Si bonding layer was prepared on the surface of a pretreated SiC ceramic substrate using atmospheric plasma spraying. The spraying powder was filled into the substrate, and the spraying path and parameters were set before spraying. The particle size (D50) of the Si powder used was 47 μm, the spraying current was 600 A, the spray gun power was 36 kW, the argon flow rate was 40 slpm, the hydrogen flow rate was 6 slpm, the powder feed rate was 30 g / min, the spraying distance was 100 mm, and the Si bonding layer thickness was 100 μm.

[0166] S3: An intermediate layer was prepared on the surface of the adhesive layer using atmospheric plasma spraying. The spraying powder used was ytterbium pyrosilicate (YbDS), with a particle size D50 of 325 μm. The spraying current was 600 A, the spray gun power was 40 KW, the argon flow rate was 40 slpm, the hydrogen flow rate was 10 slpm, the powder feed rate was 30 g / min, the spraying distance was 100 mm, and the thickness of the intermediate layer was approximately 120 μm.

[0167] S4: Use CAD software to draw a grid-like periodic structure and import it into the ultraviolet laser control software. The overall size of the periodic structure is consistent with the surface area of ​​the upper surface of the environmental barrier intermediate layer. Place the sample on the laser processing platform and adjust the position of the processing platform so that the laser spot is focused on the surface of the environmental barrier intermediate layer. The diameter of the focused laser spot is about 15μm.

[0168] S5: Set the laser processing parameters to process the intermediate layer of the environmental barrier, where the laser pulse width is 10ns, the laser power is 4W, the repetition frequency is 10kHz, the scanning speed is 100mm / s, and the number of scan repetitions is 4; the surface of the processed sample is as follows. Figure 2 As shown in (a), the laser-processed mesh etching depth is approximately 30 μm, and the spacing between the etched areas is 100 μm.

[0169] S6: Place the laser-etched SiC-based ceramic sample with the bonding layer and environmental barrier interlayer in the fixture, then fix the fixture to the sample stage of the plasma physical vapor deposition equipment and set the deposition control program; fill the powder feeder with (Gd) 0.3 Yb 0.7 2Zr2O7 powder; close the equipment chamber, check the equipment's seal, and then evacuate. When the vacuum level reaches below 0.1 mbar, fill with argon gas to 130 mbar; ignite the torch and, after the arc stabilizes, evacuate to below 3 mbar, start the control program, move the sample stage to a position 1000 mm away from the torch, and adjust the torch to face the sample; gradually increase the torch current to 1800 A, set the helium flow rate to 40 slpm, the argon flow rate to 20 slpm, and the spraying power to 60 kJ / m³. W, and preheat the sample to 800℃ using plasma jet; heat the temperature inside the powder feeder chamber to 60℃, open the powder feeding gas path, adjust the powder carrier gas flow rate to 8slpm, spray time to 20min, and deposit a coating thickness of about 100μm; close the powder feeding gas path, gradually reduce the spray gun current and plasma gas flow rate, fill with argon gas to 60mbar, then turn off the gun, extinguish the arc, cool for 20min and then turn off the vacuum pump. After the chamber is balanced with atmospheric pressure, take out the sample to obtain the environmental barrier-infrared stealth coating.

[0170] Example 2

[0171] Example 2 is similar to the preparation method of Example 1, except that in step S5 of Example 2, the laser power is 6W, the repetition frequency is 30kHz, the scanning speed is 50mm / s, and the number of scan repetitions is 2; the cross-section of the processed sample is as follows. Figure 2 As shown in (b), the laser-processed mesh etching depth is approximately 40 μm, and the spacing between the etched areas is 50 μm.

[0172] Example 3

[0173] The preparation method of Example 3 is similar to that of Example 1, except that: in step S5 of Example 3, the laser power is 10W, the repetition frequency is 20kHz, the scanning speed is 200mm / s, and the number of scanning repetitions is 5.

[0174] Example 4

[0175] The preparation method of Example 4 is similar to that of Example 1, except that: in step S2 of Example 4, the spraying current is 700A, the spray gun power is 40KW, the argon flow rate is 30slpm, the hydrogen flow rate is 8slpm, the powder feeding rate is 35g / min, and the spraying distance is 80mm.

[0176] Example 5

[0177] The preparation method of Example 5 is similar to that of Example 1, except that: in step S2 of Example 5, the spraying current is 500A, the spray gun power is 35KW, the argon flow rate is 35slpm, the hydrogen flow rate is 5slpm, the powder feeding rate is 25g / min, and the spraying distance is 90mm.

[0178] Example 6

[0179] The preparation method of Example 6 is similar to that of Example 1, except that: in step S3 of Example 6, the spraying current is 600A, the spray gun power is 45KW, the argon flow rate is 30slpm, the hydrogen flow rate is 12slpm, the powder feeding rate is 35g / min, and the spraying distance is 80mm.

[0180] Example 7

[0181] The preparation method of Example 7 is similar to that of Example 1, except that: in step S3 of Example 7, the spraying current is 650A, the spray gun power is 42KW, the argon flow rate is 35slpm, the hydrogen flow rate is 10slpm, the powder feeding rate is 25g / min, and the spraying distance is 90mm.

[0182] Example 8

[0183] The preparation method of Example 8 is similar to that of Example 1, except that: in step S6 of Example 8, the vacuum is drawn to 3mbar, the sample stage is moved to a position 1200mm away from the spray gun, the spray gun current is 1950A, the helium flow rate is set to 40slpm, the argon flow rate is set to 20slpm, the spraying power is 65kW, and the sample is preheated to 800°C using plasma jet.

[0184] Example 9

[0185] The preparation method of Example 9 is similar to that of Example 1, except that: in step S6 of Example 9, the vacuum is drawn to 1 mbar, the sample stage is moved to a position 800 mm away from the spray gun, the spray gun current is 1900 A, the helium flow rate is set to 40 slpm, the argon flow rate is set to 20 slpm, the spraying power is 62 kW, and the sample is preheated to 800 °C using plasma jet.

[0186] Comparative Example 1

[0187] Comparative Example 1 was prepared using a similar method to Example 1, except that steps S4 and S5 were omitted, the intermediate layer was not etched, and no etched area existed on the surface of the intermediate layer. The cross-section of the processed sample is shown below. Figure 2 As shown in (c).

[0188] Comparative Example 2

[0189] Comparative Example 2 is similar to the preparation method of Example 1, except that: there are no steps S4, S5 and S6 in Comparative Example 2, the intermediate layer is not etched, there is no etched area on the surface of the intermediate layer, and no infrared stealth layer is prepared.

[0190] Comparative Example 3

[0191] With dimensions of 10×10×5mm 3 SiC ceramics were used as comparative example 3.

[0192] The structural parameters of each of the above embodiments 1-9 and comparative example 1 are shown in Table 1.

[0193] Table 1

[0194]

[0195] Performance tests were conducted on the above embodiments and comparative examples, and the results are shown in Table 2. The infrared emissivity of Embodiment 1, Embodiment 2, Comparative Example 1, and Comparative Example 3 (SiC) in the 3μm~5μm band at different temperatures is shown in Table 2. Figure 3 As shown, where, Figure 3 (a) is 800℃, and (b) is 1100℃. The test conditions or standards for each performance test item are as follows:

[0196] (1) Water vapor corrosion life test: Water vapor corrosion test was conducted at 1100℃ using a mixture of water vapor and oxygen with a volume ratio of 9:1 and a flow rate of 1 s lpm. The change in sample mass after 300 h of corrosion was evaluated.

[0197] (2) Thermal insulation effect test: The thermal insulation effect of the coating was tested according to Q / AVIC06018-2013 "Test method for thermal barrier coating thermal insulation effect". The experimental temperature was 1100℃, the cooling gas flow rate was (40±0.5)m / s, and the cooling gas temperature was (500±5)℃. The temperature difference between the inner and outer walls was calculated, and the thermal insulation effect of the sample was obtained by comparing it with the blank sample.

[0198] (3) Infrared emissivity test: The sample was heated to 800℃ and 1100℃ respectively, and the infrared radiation intensity of the sample and the standard blackbody in the range of 3~5μm was tested under the same conditions to obtain the infrared emissivity.

[0199] Table 2

[0200]

[0201] As can be seen from the comparison of the results of Examples 1-9 and Comparative Examples 1-3 in Table 2, compared with Comparative Examples 1-3, the environmental barrier-infrared stealth coatings in Examples 1-9 have lower thermal conductivity and infrared emissivity, and better resistance to water vapor corrosion; indicating that the environmental barrier-infrared stealth coatings provided in this application have excellent high-temperature corrosion resistance and infrared stealth performance. The reason for this is that: in the environmental barrier-infrared stealth coatings provided in this application, the adhesive layer can be rapidly oxidized under high-temperature service conditions to generate a protective SiO2 oxide film to prevent the SiC-based ceramic matrix from being corroded; the intermediate layer has a dense structure, which can inhibit the contact and reaction between high-temperature water vapor and the SiO2 oxide film, reduce the generation and volatilization rate of Si(OH)4, and the combined effect of the adhesive layer and the intermediate layer avoids the performance degradation of the SiC-based ceramic matrix. The infrared stealth layer can reduce its infrared emissivity by diffracting and extincting its own infrared radiation through columnar cavities, and it can also reduce its surface temperature by using low thermal conductivity ceramic columnar crystals and ceramic particles to provide thermal insulation. The two work together to reduce the infrared radiation intensity of the component and achieve infrared stealth.

[0202] In addition, by Figure 2 It can be seen that the intermediate layer in Examples 1 and 2 has an etched structure, such as Figure 2 (a) and Figure 2 As shown in Figure (b), the top infrared stealth layer consists of ceramic columnar crystals, ceramic particles aggregated within the etched area, and columnar cavities above the ceramic particles, forming an environmental barrier-infrared stealth coating with a micro-nano composite structure. In contrast, the middle layer in Comparative Example 1 (which was untreated)... Figure 2 As shown in (c), the top layer consists of densely arranged ceramic columnar crystals and ceramic particles distributed in the gaps between the ceramic columnar crystals, and there are no columnar cavities.

[0203] Depend on Figure 3 It can be seen that at 800℃ ( Figure 3 (a) and 1100℃ ( Figure 3 In the middle (b) below, in the wavelength range of 3~5μm, the emissivity of pure silicon carbide (Comparative Example 3) is significantly higher than that of other coated samples, while the infrared emissivity of the samples of Example 1 and Example 2 with micro-nano composite structures is significantly lower than that of Comparative Example 1.

[0204] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0205] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An environmental barrier-infrared stealth coating, characterized in that, The infrared stealth layer comprises ceramic columnar crystals, ceramic particles, and columnar cavities between two adjacent ceramic columnar crystals, the ceramic particles are filled in the etching area, the ceramic columnar crystals are located in the unetched area of the surface of the intermediate layer having the etching area, and the columnar cavities are located above the ceramic particles. The volume ratio of the columnar cavities in the infrared stealth layer is 10%-40%, the columnar cavities penetrate the infrared stealth layer along the thickness direction of the infrared stealth layer, the width of the columnar cavities is 8 μm-15 μm, and the preparation method of the infrared stealth layer comprises plasma physical vapor deposition.

2. The environmental barrier-infrared stealth coating of claim 1, wherein, The infrared stealth layer has at least one of the following characteristics (1)-(6): (1) The material of the infrared stealth layer comprises one or more of rare earth zirconate and rare earth hafnate; (2) The width of the ceramic columnar crystals is 10 μm-40 μm; (3) The thickness of the infrared stealth layer is 100 μm-150 μm; (4) The average particle size of the ceramic particles is 0.5 μm-10 μm; (5) The volume ratio of the ceramic columnar crystals in the infrared stealth layer is 40%-80%; (6) The volume ratio of the ceramic particles in the infrared stealth layer is 5%-30%.

3. The environmental barrier-infrared stealth coating of claim 1, wherein, The intermediate layer has at least one of the following characteristics (1)-(4): (1) The depth of the etching area is 5 μm-50 μm, the width of the etching area is 10 μm-30 μm, and the distance between two adjacent etching areas is 20 μm-200 μm; (2) The thickness of the intermediate layer is 80 μm-150 μm; (3) The material of the intermediate layer comprises one or both of ytterium silicate and ytterium pyrosilicate; (4) The porosity of the intermediate layer is <10%.

4. The environmental barrier-infrared stealth coating according to any one of claims 1 to 3, wherein The bonding layer has at least one of the following characteristics (1)-(2): (1) The thickness of the bonding layer is 60 μm-125 μm; (2) The material of the bonding layer comprises Si.

5. The environmental barrier-infrared stealth coating according to any one of claims 1 to 3, wherein The SiC-based ceramic substrate is selected from a silicon carbide substrate or a silicon carbide fiber reinforced silicon carbide ceramic matrix composite substrate.

6. A method of preparing an environmental barrier-infrared stealth coating, characterized in that, The method comprises the following steps: sandblasting pretreatment is performed on at least one side surface of a SiC-based ceramic substrate; a bonding layer is formed on the surface of the SiC-based ceramic substrate after sandblasting pretreatment, and an intermediate layer is formed on the surface of the bonding layer away from the SiC-based ceramic substrate; etching treatment is performed on the intermediate layer to form at least one etching area on the surface of the intermediate layer away from the bonding layer; an infrared stealth layer is formed on the surface of the intermediate layer having the etching area, the infrared stealth layer comprises ceramic columnar crystals, ceramic particles, and columnar cavities between two adjacent ceramic columnar crystals, the ceramic particles are filled in the etching area, the ceramic columnar crystals are located in the unetched area of the surface of the intermediate layer having the etching area, and the columnar cavities are located above the ceramic particles; The volume ratio of the columnar cavity in the infrared stealth layer is 10%-40%; the columnar cavity penetrates the infrared stealth layer along the thickness direction of the infrared stealth layer, and the width of the columnar cavity is 8-15 μm; The method for forming the infrared stealth layer comprises plasma physical vapor deposition.

7. The production method according to claim 6, wherein The preparation method of the adhesive layer comprises atmospheric plasma spraying.

8. The production method according to claim 7, wherein The preparation method of the adhesive layer comprises at least one of the following conditions (1)-(6): (1) the spraying current of the atmospheric plasma spraying is 500-700 A; (2) the spraying power of the atmospheric plasma spraying is 35-40 KW; (3) the gas used in the atmospheric plasma spraying comprises argon, and the flow rate of argon is 30-40 slpm; (4) the gas used in the atmospheric plasma spraying comprises hydrogen, and the flow rate of hydrogen is 5-8 slpm; (5) the powder feeding rate of the atmospheric plasma spraying is 25-35 g / min; (6) the spraying distance of the atmospheric plasma spraying is 80-100 mm.

9. The production method according to claim 6, wherein The preparation method of the intermediate layer comprises atmospheric plasma spraying.

10. The production method according to claim 9, wherein The preparation method of the intermediate layer comprises at least one of the following conditions (1)-(6): (1) the spraying current of the atmospheric plasma spraying is 500-700 A; (2) the spraying power of the atmospheric plasma spraying is 40-45 KW; (3) the gas used in the atmospheric plasma spraying comprises argon, and the flow rate of argon is 30-40 slpm; (4) the gas used in the atmospheric plasma spraying comprises hydrogen, and the flow rate of hydrogen is 8-12 slpm; (5) the powder feeding rate of the atmospheric plasma spraying is 25-35 g / min; (6) the spraying distance of the atmospheric plasma spraying is 80-100 mm.

11. The production method according to claim 6, wherein The preparation method of the intermediate layer comprises plasma physical vapor deposition.

12. The production method according to claim 11, wherein The preparation method of the intermediate layer comprises at least one of the following conditions (1)-(5): (1) the deposition current of the plasma physical vapor deposition is 1100-1200 A; (2) the deposition power of the plasma physical vapor deposition is 30-40 KW; (3) the plasma gas used in the plasma physical vapor deposition comprises argon and helium, the flow rate of argon is 20-40 slpm, and the flow rate of helium is 30-60 slpm; (4) the powder feeding rate of the plasma physical vapor deposition is 8-10 g / min; (5) the spraying distance of the plasma physical vapor deposition is 600-800 mm.

13. The production method according to claim 6, wherein The intermediate layer is subjected to etching treatment by using a pulsed laser.

14. The production method according to claim 13, wherein The etching treatment comprises at least one of the following conditions (1)-(7): (1) the central wavelength of the laser of the pulsed laser is 355 nm; (2) the focusing spot diameter of the laser of the pulsed laser is 10-20 μm; (3) the pulse width of the laser of the pulsed laser is 10-20 ns; (4) the laser power of the pulsed laser is 3-10 W; (5) the repetition frequency of the pulsed laser is 10 kHz-30 kHz; (6) the scanning speed of the pulsed laser is 50 mm / s-200 mm / s; (7) the scanning repetition number of the pulsed laser is 1-5 times.

15. The production method according to claim 6, wherein The preparation method of the infrared stealth layer comprises at least one of the following conditions (1)-(7): (1) the vacuum degree of the plasma physical vapor deposition is 1 mbar-5 mbar; (2) the working gas used in the plasma physical vapor deposition comprises argon and helium, the flow rate of argon is 20 slpm-40 slpm, and the flow rate of helium is 30 slpm-60 slpm; (3) the spray gun distance of the plasma physical vapor deposition is 800 mm-1200 mm; (4) the deposition current of the plasma physical vapor deposition is 1800 A-2100 A; (5) the deposition power of the plasma physical vapor deposition is 55 kW-65 kW; (6) the powder feeding rate of the plasma physical vapor deposition is 8 g / min-10 g / min; (7) the sample preheating temperature of the plasma physical vapor deposition is 600℃-800℃.

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