Thermal environment barrier coating and preparation method thereof, and high temperature resistant component

Abstract

In order to overcome the problem of insufficient water-oxygen corrosion resistance in existing thermal environment barrier coatings, the present invention provides a thermal environment barrier coating comprising a dense layer and a high strain tolerance layer, wherein the dense layer comprises rare earth silicate, and the high strain tolerance layer comprises high entropy ceramics. At the same time, the present invention also discloses a high-temperature resistant component comprising the above-mentioned thermal environment barrier coating and a method for preparing the above-mentioned thermal environment barrier coating. The thermal environment barrier coating provided by the present invention is formed by compounding high-density rare earth silicate and high-strain tolerance high-entropy ceramics to form a thermal environment barrier coating, which can effectively reduce the problems of the thermal environment barrier coating being prone to crack channels, direct contact with water and oxygen to cause water and oxygen corrosion failure, etc., thereby achieving the effect of increasing the overall water and oxygen corrosion resistance. The introduction of low thermal conductivity high entropy ceramics not only increases the overall water and oxygen corrosion resistance, but also can further increase the overall thermal insulation effect, thereby improving the engine efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature protective coatings, and in particular relates to a thermal environment barrier coating and a preparation method thereof, and a high-temperature resistant component. Background Art

[0002] Superalloys are currently the most widely used and mature materials for high-temperature structural components in aircraft engines. They offer high-temperature resistance, oxidation resistance, corrosion resistance, and fatigue resistance, as well as high high-temperature strength, creep strength, and endurance strength. With the development of the aviation industry and gas turbines, components such as turbine blades will be subjected to even higher temperatures, making superalloys no longer suitable. Therefore, the search for new high-temperature-resistant materials has become a new demand.

[0003] Ceramic matrix composites (CMCs) offer low density (approximately one-third that of superalloys), high specific strength, high specific modulus, and excellent high-temperature thermodynamic properties. Compared to superalloys, CMCs offer superior resistance to high-temperature oxidation and creep, as well as a limited ability to resist crack propagation, making them a promising alternative to superalloys as new matrix materials. Silicon carbide ceramics and related composites have a low density, only 20%-30% that of superalloys. They offer strong designability, with mechanical properties and thermal conductivity significantly improving with increasing fiber content. They also exhibit excellent high-temperature mechanical properties, with strength exhibiting no significant decrease with increasing temperature. They also exhibit a high fatigue limit, reaching 90% of static strength, and excellent resistance to oxidation, corrosion, and wear. They are considered a prime candidate for high-temperature components in the next generation of high-thrust-to-weight ratio aeroengines. However, in water-rich, oxygen-rich fuel gas environments, silicon carbide ceramics experience rapid performance degradation due to corrosion from high-temperature water vapor. Therefore, research on silicon carbide ceramic materials and high-temperature protection technologies is of great significance for my country's future high-thrust-to-weight ratio aeroengines.

[0004] Environmental barrier coatings (EBCs) are essential surface protective coatings for ceramic materials. They create a barrier between high-temperature structural materials and the harsh engine environment (corrosive media, high-speed airflow, etc.), preventing or reducing the impact of the engine environment on the performance of high-temperature structural materials. Rare earth silicate systems, currently widely recognized EBC materials, exhibit excellent resistance to water and oxygen corrosion. For example, ytterbium disilicate (Yb2Si2O7) exhibits excellent resistance to water and oxygen corrosion under quasi-static conditions. However, in actual service environments with rapid flow of water and oxygen corrosive media, material loss, pore formation, and microcracks can occur, reducing their resistance to water and oxygen.

[0005] The thermal barrier coating formed by combining thermal barrier coating and environmental barrier coating is the latest generation of high temperature protective coating system. The team led by Guo Hongbo from Beijing University of Aeronautics and Astronautics prepared Si bonding layer and Yb2SiO5 ytterbium monosilicate intermediate layer by APS technology, and prepared (Gd 0.9Yb 0.1 )2Zr2O7 surface layer to form a thermal environment barrier coating system, and studied its overall anti-sintering performance at 1300℃ and 1400℃. However, the thermal expansion coefficients of ytterbium monosilicate and SiC in this study are quite different, which makes it easy for cracks to form water-oxygen corrosion channels due to thermal mismatch stress. In addition, there are a large number of microcracks between the layered structures prepared by APS technology. The presence of microcracks provides channels for water-oxygen corrosion, which is not conducive to water-oxygen corrosion protection. Similarly, the team prepared Hf by APS technology. 0.84 Y 0.16 O 1.92 / Yb2SiO5 / Si thermal barrier coating system and carried out oxidation experiments at 1300℃ for up to 100h. However, due to the Hf 0.84 Y 0.16 O 1.92 There are a lot of micro cracks and pores between the surface layer and the Yb2SiO5 intermediate layer, which is not conducive to water and oxygen corrosion protection. The team led by Cao Xueqiang of Wuhan University of Technology used APS technology to prepare LaMgAl 11 O 19 / Yb2Si2O7 / Si thermal barrier coating system and conducted water-oxygen corrosion research at 1300℃. However, due to the presence of a large number of interlaminar microcracks and pore structures in the thermal barrier surface layer and the environmental barrier intermediate layer prepared by APS technology, the thermal barrier coating showed vertical cracks or through-crack structures during the heat preservation heat treatment stage after spraying and before the water-oxygen corrosion experiment, providing a rapid diffusion channel for the water-oxygen corrosion medium. After 60h of water-oxygen corrosion at 1300℃, a large number of through-cracks appeared. Similarly, the team prepared LaMgAl by APS technology. 11 O 19 / Yb2SiO5 / Si thermal barrier coating system and the oxidation behavior at 1300℃ was studied. 11 O 19 There is a large difference in thermal expansion coefficient between Yb2SiO5 and SiC. There are a large number of through cracks inside the sprayed coating. After 50-100 hours of oxidation, the opening displacement of the through crack tips increases significantly, which will provide a rapid diffusion channel for water and oxygen corrosion media.

[0006] The coating system of the Beijing Institute of Aeronautical Materials of China (CN 116253584 B) is a Yb2O3-Y2O3-HfO2 ternary oxide surface layer / Yb2Si2O7-Yb2SiO5 doped intermediate layer / R-Al-Si-O glass-ceramic bonding layer. The gradient Yb2Si2O7-Yb2SiO5 is prepared using APS technology, which also has problems such as excessive porosity and insufficient water and oxygen protection. The introduction of Yb2SiO5 increases the overall thermal expansion coefficient, generating greater thermal mismatch stress. In addition, the bonding layer prepared by the slurry method results in low overall bonding strength of the coating. The Aerospace Special Materials and Process Technology Research Institute (CN 109336647 B) uses VPS technology to prepare an HfO2 / HfO2-Yb2SiO5 doped / Yb2SiO5 / Si thermal barrier coating system. However, because the hafnium oxide surface layer prepared by VPS technology does not have a high strain tolerance structure, it has problems such as insufficient thermal barrier performance. In addition, the introduction of Yb2SiO5 increases the overall thermal expansion coefficient, generating greater thermal mismatch stress. Summary of the Invention

[0007] In view of the problem that existing thermal environment barrier coatings have insufficient resistance to water and oxygen corrosion, the present invention provides a thermal environment barrier coating and a preparation method thereof, and a high-temperature resistant component.

[0008] The technical solutions adopted by the present invention to solve the above technical problems are as follows:

[0009] In one aspect, the present invention provides a thermal environment barrier coating, comprising a dense layer and a high strain tolerance layer, wherein the dense layer comprises rare earth silicate, and the high strain tolerance layer comprises high entropy ceramic.

[0010] Optionally, the high strain tolerance layer includes a plurality of feather-shaped columnar structures arranged on the surface of the dense layer, and the feather-shaped columnar structures are composed of the high entropy ceramic.

[0011] Optionally, the high entropy ceramic comprises (Y 0.2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 )2Zr2O7.

[0012] Optionally, the rare earth silicate includes one or more of rare earth monosilicates and rare earth disilicates, and the rare earth elements of the rare earth silicate include one or more of ytterbium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, yttrium and erbium.

[0013] Optionally, the rare earth silicate is selected from rare earth double silicate, and the rare earth double silicate includes Yb2Si2O7.

[0014] Optionally, the thickness of the dense layer is 75-200 μm.

[0015] Optionally, the high strain tolerance layer has a thickness of 150-300 μm.

[0016] Optionally, a Si layer is further included, the Si layer being used for contacting the substrate, the Si layer being located on a side of the dense layer away from the high strain tolerance layer, and the thickness of the Si layer being 50-150 μm.

[0017] In another aspect, the present invention provides a high-temperature resistant component, comprising a substrate and the thermal environment barrier coating as described above disposed on the substrate, wherein the substrate is selected from SiC.

[0018] In another aspect, the present invention provides a method for preparing the thermal barrier coating as described above, comprising the following steps:

[0019] Using rare earth silicates as raw materials for the deposition of dense layers;

[0020] A high entropy ceramic is deposited on the surface of the dense layer to form a high strain tolerance layer.

[0021] Optionally, the method further includes: using SiC as a substrate, depositing a Si layer on the substrate, and forming the dense layer on the Si layer.

[0022] Optionally, the Si layer, the dense layer and the high strain tolerance layer are all prepared by using PS-PVD technology.

[0023] Optionally, the PS-PVD preparation parameters of the Si layer are: spraying current of 1500-1700 A, argon flow rate of 100-120 NLPM (standard liters per minute), hydrogen flow rate of 4-7 NLPM (standard liters per minute), and chamber pressure of 35-50 mbar; and / or

[0024] The PS-PVD preparation parameters of the dense layer are: spraying current of 2400-2600A, argon flow rate of 90-110 NLPM (standard liters per minute), helium flow rate of 15-30 NLPM (standard liters per minute), and chamber pressure of 1.2-2.0 mbar; and / or

[0025] The PS-PVD preparation parameters of the high strain tolerance layer are: the current is controlled at 2400~2600A, the argon flow rate is 25~45NLPM (standard liters per minute), and the helium flow rate is 50~70NLPM (standard liters per minute).

[0026] Optionally, after the dense layer is sprayed, the sprayed dense layer is heat treated at a temperature of 1250-1350° C. and for a time of 2-10 hours.

[0027] According to the thermal barrier coating provided by the present invention, rare earth silicate is used as a high-density layer, which can block the corrosion of high-temperature water and oxygen on the substrate, and achieves good matching with the substrate through the intrinsic low thermal expansion coefficient of the material, avoiding excessive thermal mismatch stress, thereby making it possible to prepare a high-density structure. The high-density structure is used to further improve the water-oxygen corrosion resistance by avoiding holes or microcracks to form water-oxygen diffusion fast channels; at the same time, in order to avoid the rapid flow of water-oxygen mixed gas to scour the high-density layer and cause rapid degradation of the material and structure, the present invention adopts high-entropy ceramics in the high A high strain tolerance layer is formed on the surface of the dense layer, which not only provides excellent protection against water and oxygen corrosion through the material's intrinsic high water and oxygen activation energy, but also significantly reduces the gas flow rate near the high-density layer, thereby avoiding direct contact between the fast-flowing water and oxygen mixture and the rare earth silicate, leading to rapid degradation of the material and structure. In addition, the high strain tolerance structure can reduce the thermal mismatch stress of the surface layer, thereby avoiding premature spalling and failure of the surface layer. In addition, the high entropy effect can be used to reduce the intrinsic thermal conductivity of the material, thereby further improving the overall thermal insulation effect of the coating system and reducing the degradation rate and failure probability of the high-density layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the structure of the thermal barrier coating provided by the present invention;

[0029] Figure 2 This is a cross-sectional morphology of the thermal barrier coating prepared in Example 1;

[0030] Figure 3 This is a cross-sectional morphology of the target thermal barrier coating prepared in Example 2 after 50 hours of water-oxygen corrosion;

[0031] Figure 4 This is a cross-sectional morphology of the environmental barrier coating prepared in Comparative Example 2 after 50 hours of water-oxygen corrosion;

[0032] Figure 5 This is a cross-sectional morphology of the target thermal barrier coating prepared in Example 3 after 150 hours of water-oxygen corrosion;

[0033] Figure 6 This is a cross-sectional morphology of the environmental barrier coating prepared in Comparative Example 3 after 150 hours of water-oxygen corrosion;

[0034] Figure 7 This is a cross-sectional morphology of the target thermal barrier coating prepared in Example 4 after 300 hours of water-oxygen corrosion;

[0035] Figure 8 This is a cross-sectional morphology of the environmental barrier coating prepared in Comparative Example 4 after 300 hours of water-oxygen corrosion;

[0036] Figure 9 Thickness curves of SiO2 thermally grown oxide in the sprayed state or after water-oxygen corrosion of Examples 2, 3, and 4 and Comparative Examples 2, 3, and 4;

[0037] The reference numerals in the drawings of the specification are as follows:

[0038] 1. Substrate; 2. Si layer; 3. Dense layer; 4. High strain tolerance layer. DETAILED DESCRIPTION

[0039] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] When a layer is described as being "on" or "over" another layer or substrate, it should be understood that unless explicitly stated otherwise, the layers may be directly in contact with each other or have another layer or feature between them. Therefore, these terms simply describe the relative position of layers relative to each other and do not necessarily mean "above," as the relative position of above or below depends on the orientation of the device relative to the viewer.

[0041] See also Figure 1 As shown, an embodiment of the present invention provides a thermal barrier coating, comprising a dense layer 3 and a high strain tolerance layer 4, wherein the dense layer 3 comprises rare earth silicate, and the high strain tolerance layer 4 comprises high entropy ceramic.

[0042] In the thermal barrier coating, rare earth silicate is used as the high-density layer 3, which can block the corrosion of high-temperature water and oxygen on the substrate 1. The low thermal expansion coefficient of the material is used to achieve a good match with the substrate 1, avoiding excessive thermal mismatch stress, thereby making it possible to prepare a high-density structure. The high-density structure is used to further improve the water-oxygen corrosion resistance by avoiding holes or microcracks to form a fast water-oxygen diffusion channel; at the same time, in order to avoid the rapid flow of water-oxygen mixed gas from scouring the high-density layer 3 and causing rapid degradation of the material and structure, the present invention uses high-entropy ceramics in the high-density layer. A high strain tolerance layer 4 is formed on the surface of 3, which not only provides excellent anti-water and oxygen corrosion protection through the high water and oxygen activation energy of the material itself, but also significantly reduces the gas flow rate near the high-density layer 3, thereby avoiding direct contact between the fast-flowing water and oxygen mixture and the rare earth silicate, which leads to rapid degradation of the material and structure. In addition, the high strain tolerance structure can reduce the thermal mismatch stress of the surface layer, thereby avoiding premature spalling and failure of the surface layer. In addition, the high entropy effect can also reduce the intrinsic thermal conductivity of the material, thereby further improving the overall thermal insulation effect of the coating system and reducing the degradation rate and failure probability of the high-density layer 3.

[0043] In some embodiments, the high strain tolerance layer 4 includes a plurality of feather-shaped structures arranged on the surface of the dense layer 3 , and the feather-shaped structures are made of the high entropy ceramic.

[0044] In the description of the present invention, the term "feather-like structure" refers to slender columnar crystals similar to feathers. These crystals grow on the surface of the dense layer 3 in a direction perpendicular to the surface of the dense layer 3 and show obvious directional arrangement characteristics. The crystals are not completely fitted together, and gaps are retained to achieve their high strain tolerance.

[0045] The feather-like structure formed by the high-entropy ceramic provides high strain tolerance, allowing rare earth silicates with significantly different CTEs to bond well with the high-entropy ceramic without generating microcracks. This high strain tolerance allows the high-entropy ceramic layer to better cope with the effects of in-plane thermal mismatch stress during thermal cycling, reducing thermal mismatch stress in the surface layer and making it less susceptible to vertical cracks and other structures. This reduces the risk of premature spalling and improves thermal cycling life. Furthermore, in a rapidly flowing, high-temperature water and oxygen environment, the feather-like structure can reduce the surface high-temperature water and oxygen flow rate, acting as an environmental barrier to the dense layer 3, providing water and oxygen protection for the dense layer 3 and addressing the issue of insufficient protection of rare earth silicates in dynamic water and oxygen environments.

[0046] In some embodiments, the height of the feather-like structure is 150-300 μm.

[0047] In some embodiments, the high entropy ceramic comprises a rare earth zirconate.

[0048] Rare earth zirconate high entropy ceramics have excellent thermal stability and resistance to water, oxygen and molten salt corrosion, and can provide additional water and oxygen protection for thermal environment barrier coatings.

[0049] In a preferred embodiment, the high entropy ceramic comprises (Y 0.2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 )2Zr2O7.

[0050] (Y 0.2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 ) The intrinsic properties of 2Zr2O7 include high water-oxygen activation energy and low thermal conductivity. This high water-oxygen activation energy gives the high strain tolerance layer 4 excellent high-temperature stability in a high-velocity water-oxygen environment, thereby separating the dense layer 3 of rare earth silicate from high-velocity water vapor, significantly reducing the gas flow rate near the dense layer 3, thereby preventing the fast-flowing water-oxygen mixture from directly contacting the dense layer 3 and causing rapid degradation of the material and structure. And (Y0.2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 ) 2Zr2O7 enhances phonon scattering through the high entropy effect, resulting in low intrinsic thermal conductivity, which can increase the overall thermal insulation effect of the coating system, and is of great significance for increasing the operating temperature of engines, reducing fuel consumption, and improving thrust-to-weight ratio.

[0051] In some embodiments, the rare earth silicate comprises one or more of rare earth monosilicates and rare earth disilicates, and the rare earth elements of the rare earth silicate comprise one or more of ytterbium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, yttrium, and erbium.

[0052] In some embodiments, the dense layer 3 is a single layer or multiple layers. When the dense layer 3 is a single layer, the dense layer 3 may include a single rare earth silicate or multiple rare earth silicates; when the dense layer 3 is a multiple layer, each of the dense layers 3 independently includes a single rare earth silicate or multiple rare earth silicates, and the materials of the multiple layers of dense layer 3 may be the same or different.

[0053] In a preferred embodiment, the dense layer 3 is a single layer of rare earth silicate.

[0054] In a preferred embodiment, the rare earth silicate is selected from rare earth double silicate, and the rare earth double silicate includes Yb2Si2O7.

[0055] Ytterbium disilicate (Yb2Si2O7) has excellent resistance to water and oxygen corrosion in a quasi-static corrosion environment. Compared with monosilicate, which has a higher thermal expansion coefficient, its intrinsic material property of thermal expansion coefficient is close to that of SiC, making it possible to prepare a highly dense layered structure on the SiC substrate 1. The highly dense layered structure is conducive to improving protection and reducing the generation of various corrosion channels.

[0056] Theoretically, the purity of Yb2Si2O7 in the dense layer 3 should be as high as possible, but due to the limitations of raw material purity, synthesis process and preparation process, the presence of a certain amount of impurities or by-products is allowed without affecting its function. For example, in some embodiments, the mass content of Yb2Si2O7 in the dense layer 3 is 90% or more. Preferably, the mass content of Yb2Si2O7 in the dense layer 3 is 93% or more. More preferably, the mass content of Yb2Si2O7 in the dense layer 3 is 96% or more.

[0057] In some embodiments, the thickness of the dense layer 3 is 75-200 μm.

[0058] If the thickness of the dense layer 3 is too low, its protective effect is limited, and it is easy to form holes or microcracks connected to the substrate 1 in a high-temperature water and oxygen environment, affecting the protective effect on the substrate 1.

[0059] In some embodiments, the high strain tolerance layer 4 has a thickness of 150-300 μm.

[0060] The thickness of the high strain tolerance layer 4 is related to the height of the feather column structure. Generally, the column heights of the feather column structure vary. The thickness of the high strain tolerance layer 4 is determined by the height of the taller column in the feather column structure.

[0061] If the thickness of the high strain tolerance layer 4 is too thin, it is easy to be worn out in a long-term water-oxygen corrosion environment, resulting in exposure of the dense layer 3 , which reduces the protective effect of the dense layer 3 .

[0062] In some embodiments, the thermal barrier coating further includes a Si layer 2, which is used to contact the substrate 1. The Si layer 2 is located on the side of the dense layer 3 away from the high strain tolerance layer 4, and the thickness of the Si layer 2 is 50-150 μm.

[0063] Si layer 2, located between substrate 1 and dense layer 3, acts as a bonding layer. Its bonding with substrate 1 influences the thermal barrier coating system's bonding performance. From a material design perspective, the Si employed in this invention has a similar thermal expansion coefficient to that of SiC substrate 1, resulting in high compatibility and low thermal mismatch stress between the two, improving the coating system's bonding performance.

[0064] In some embodiments, a thermally grown oxide layer is formed on a side of the Si layer 2 facing away from the substrate 1 .

[0065] The thermally grown oxide layer is formed by the Si layer 2 reacting with water and oxygen under high temperature conditions during the long-term protection of the substrate 1. The formed thermally grown oxide layer has certain barrier properties and prevents oxidation of the substrate 1.

[0066] In some optional embodiments, hafnium oxide is provided on the side of the Si layer 2 facing away from the substrate 1 .

[0067] Another embodiment of the present invention provides a high-temperature resistant component, including a substrate and the thermal environment barrier coating as described above disposed on the substrate.

[0068] Exemplary applications of the high-temperature resistant components include turbine components, specifically, those located in the compressor section (e.g., compressor blades, blades, and / or shrouds), combustion section (e.g., combustor, liner, and / or heat shield), or turbine section (e.g., turbine blades, blades, and / or shrouds). Application scenarios of the turbine components include high-bypass turbofan jet engines, turbojets, turboprop engines, or turboshaft gas turbine engines, as well as industrial and marine gas turbine engines and auxiliary power units.

[0069] In one embodiment, the substrate is selected from SiC.

[0070] Another embodiment of the present invention provides a method for preparing the thermal barrier coating as described above, comprising the following steps:

[0071] Using rare earth silicates as raw materials for the deposition of dense layers;

[0072] A high entropy ceramic is deposited on the surface of the dense layer to form a high strain tolerance layer.

[0073] The present invention uses highly dense rare earth silicates and high-strain tolerance high-entropy ceramics to form a composite thermal barrier coating, which can effectively reduce the problems of the thermal barrier coating being prone to crack channels and water-oxygen corrosion failure caused by direct contact with water and oxygen, thereby achieving the effect of increasing the overall resistance to water-oxygen corrosion. The introduction of low thermal conductivity high-entropy ceramics not only increases the overall resistance to water-oxygen corrosion, but also can further increase the overall thermal insulation effect, thereby improving the engine's efficiency.

[0074] In some embodiments, the preparation method further includes: using SiC as a substrate, depositing a Si layer on the substrate, and forming the dense layer on the Si layer.

[0075] In some embodiments, the Si layer, the dense layer and the high strain tolerance layer are prepared by one or more methods selected from the group consisting of plasma spraying, thermal spraying, ion plasma deposition, physical vapor deposition, chemical vapor deposition and atomic layer deposition.

[0076] In a preferred embodiment, the Si layer, the dense layer and the high strain tolerance layer are all prepared by using PS-PVD technology.

[0077] Compared with other existing preparation methods, the Si layer and dense layer prepared by the PS-PVD technology in the present invention have a highly dense layered structure. Among them, the dense Si can effectively prevent oxygen from oxidizing the SiC substrate in a high-temperature environment, thereby increasing the bonding performance of the coating system and the protective performance of the SiC substrate. The dense layer of the high-density layered structure improves the water and oxygen protection capability by avoiding the formation of fast water and oxygen diffusion channels through holes and microcracks. Compared with other preparation technologies, such as APS technology, the rare earth silicate dense layer prepared by PS-PVD technology avoids the formation of holes or microcracks and has a significantly improved density, resulting in a better water and oxygen protection effect.

[0078] PS-PVD technology combines the characteristics of APS and EB-PVD technologies, and can efficiently deposit a high strain tolerance layer with a feather-like structure and a dense layer with a high-density layered structure. The high strain tolerance of the feather-like structure can reduce the impact of the difference in the coefficient of thermal expansion (CTE), and the high-density layered structure is conducive to improving protection and reducing the generation of various corrosion channels.

[0079] In some embodiments, the PS-PVD preparation parameters of the Si layer are: spraying current of 1500~1700A, argon flow rate of 100~120NLPM (standard liters per minute), hydrogen flow rate of 4~7NLPM (standard liters per minute), and chamber pressure of 35~50mbar.

[0080] In some embodiments, the PS-PVD preparation parameters of the dense layer are: spraying current of 2400~2600A, argon flow rate of 90~110NLPM (standard liters per minute), helium flow rate of 15~30NLPM (standard liters per minute), and chamber pressure of 1.2~2.0mbar.

[0081] When the spraying parameters described above are used, the Si and Yb2Si2O7 powders can be fully melted during the high-temperature spraying process, forming a liquid-phase spraying mechanism to prepare Si layers and Yb2Si2O7 layers with highly dense layered structures.

[0082] In some embodiments, the PS-PVD preparation parameters of the high strain tolerance layer are: current controlled at 2400-2600 A, argon flow rate at 25-45 NLPM (standard liters per minute), and helium flow rate at 50-70 NLPM (standard liters per minute).

[0083] The spraying parameters described above enable the spraying to proceed in a gas-liquid-solid multiphase deposition mechanism, thereby producing a feather-like structure with high strain tolerance. The high strain tolerance structure can reduce the thermal mismatch stress of the high entropy ceramic, thereby reducing the risk of premature spalling.

[0084] In some embodiments, after the dense layer is sprayed, the sprayed dense layer is heat treated at a temperature of 1250-1350° C. for a time of 2-10 hours.

[0085] During the heat treatment process, the heating and cooling rate is 5°C / min.

[0086] By continuing to heat treat the Yb2Si2O7 layer, the microcracks in the Yb2Si2O7 layer can be healed, the internal amorphous Yb2SiO5 can be reduced, and the generation of microcracks caused by the difference in thermal expansion coefficient between Yb2SiO5 and SiC can be avoided.

[0087] In some embodiments, the substrate is surface treated before the Si layer is formed.

[0088] The surface treatment includes one or more of ultrasonic cleaning, organic solvent cleaning, surface roughening treatment, chemical treatment, heat treatment, plasma treatment and laser treatment.

[0089] The surface roughening treatment includes one or more of sandblasting and mechanical grinding.

[0090] The chemical treatment includes one or more of acid treatment and alkali treatment.

[0091] Surface treatment is used to remove impurities from the substrate surface and increase the bonding strength with other layers.

[0092] The present invention is further described below with reference to the following examples.

[0093] Example 1

[0094] This embodiment is used to illustrate the thermal barrier coating and its preparation method disclosed in the present invention, including the following steps:

[0095] S1. Sandblast with No. 60 abrasive at 0.6 MPa, then with No. 120 corundum abrasive at 0.4 MPa, and ultrasonically clean with anhydrous ethanol for 10 min.

[0096] S2. The Si layer was deposited using PS-PVD technology with a spray distance of 450 mm, a spray temperature of 650–800°C, a spray gun speed of 500 mm / s, a spray current of 1650 A, an argon flow rate of 110 NLPM (standard liters per minute), and a hydrogen flow rate of 6 NLPM.

[0097] S3. The Yb2Si2O7 layer was deposited using PS-PVD technology with a spray distance of 950 mm, a spray temperature controlled between 900°C and 1100°C, a spray speed of 800 mm / s, a spray current of 2600 A, an argon flow rate of 100 NLPM, and a helium flow rate of 20 NLPM.

[0098] S4. After spraying the Yb2Si2O7 layer, remove the sample and keep it in an air atmosphere at 1300°C for 3 hours at a heating and cooling rate of 5°C / min;

[0099] S5. Prepared by PS-PVD technology (Y 0.2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 ) 2Zr2O7 high entropy ceramic layer, the spraying distance is controlled at 1000mm, the spraying temperature is controlled at 900~1100℃, the spraying gun speed is 500mm / s, the current is controlled at 2600A, the argon flow rate is controlled at 35NLPM, and the helium flow rate is controlled at 60NLPM to obtain the target thermal environment barrier coating.

[0100] The thermal barrier coating was polished and its cross section was observed by electron microscope. The results are as follows: Figure 2 As shown by Figure 2 It can be seen that the Si layer and the Yb2Si2O7 layer are both dense structures, while the high entropy ceramic layer is a high strain tolerance layer with a feather-like structure.

[0101] Comparative Example 1

[0102] This comparative example is used to illustrate the thermal barrier coating and its preparation method disclosed in the present invention. The preparation method is the implementation steps of Example 1 except for the preparation of the high entropy ceramic layer, that is, S1 to S4 in Example 1, and specifically includes the following steps:

[0103] S1. Sandblast with No. 60 abrasive at 0.6 MPa, then with No. 120 corundum abrasive at 0.4 MPa, and ultrasonically clean with anhydrous ethanol for 10 min.

[0104] S2. Si was prepared using PS-PVD technology with a spray distance of 450 mm, a spray temperature of 650-800°C, a spray gun speed of 500 mm / s, a spray current of 1650 A, an argon flow rate of 110 NLPM (standard liters per minute), and a hydrogen flow rate of 6 NLPM.

[0105] S3. Yb2Si2O7 layer was prepared using Yb2Si2O7 technology with a spray distance of 950 mm, a spray temperature of 900-1100°C, a spray gun speed of 800 mm / s, a spray current of 2600 A, an argon flow rate of 100 NLPM, and a helium flow rate of 20 NLPM.

[0106] S4. After spraying the Yb2Si2O7 layer, remove the sample and keep it in an air atmosphere at 1300°C for 3 hours at a heating and cooling rate of 5°C / min to obtain the target thermal barrier coating.

[0107] Performance Testing

[0108] The thermal barrier coatings prepared in Example 1 and Comparative Example 1 were measured for thickness of the Yb2Si2O7 layer and the oxide layer on the Si layer using a scanning electron microscope, and the test results were entered into Table 1.

[0109] Table 1

[0110] From the test results in Table 1, it can be seen that no obvious thermally grown oxide appears in Example 1 and Comparative Example 1 after heat treatment. This is related to the density of the Yb2Si2O7 layer. The dense structure of the Yb2Si2O7 layer increases the protection of the interior.

[0111] Example 2

[0112] This embodiment is used to illustrate the thermal barrier coating and its preparation method disclosed in the present invention, including the following steps:

[0113] S1. Sandblasting with No. 60 abrasive at 0.6 MPa, then sandblasting with No. 120 corundum abrasive at 0.4 MPa, and ultrasonic cleaning with anhydrous ethanol for 10 min;

[0114] S2. The Si layer was deposited using PS-PVD technology with a spray distance of 500 mm, a spray temperature of 650–800°C, a spray gun speed of 450 mm / s, a spray current of 1550 A, an argon flow rate of 120 NLPM (standard liters per minute), and a hydrogen flow rate of 7 NLPM.

[0115] S3. Preparation of Yb2Si2O7 layer, spraying distance is 900mm, spraying temperature is controlled between 900 and 1100℃, spraying gun travel is 750mm / s, spraying current is controlled at 2500A, argon flow rate is 110NLPM, helium flow rate is 25NLPM;

[0116] S4. After spraying the Yb2Si2O7 layer, remove the sample and keep it in an air atmosphere at 1300°C for 3 hours at a heating and cooling rate of 5°C / min;

[0117] S5. Prepared by PS-PVD technology (Y 0.2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 ) 2Zr2O7 high entropy ceramic layer, the spraying distance is controlled at 950mm, the spraying temperature is controlled at 900~1100℃, the spraying gun travel is 450mm / s, the current is controlled at 2600A, the argon flow rate is 35NLPM, and the helium flow rate is 60NLPM to obtain the target thermal environment barrier coating.

[0118] Comparative Example 2

[0119] This comparative example is used to illustrate the thermal barrier coating and its preparation method disclosed in the present invention. The preparation method is the implementation steps of Example 2 except for the preparation of the high entropy ceramic layer, that is, S1 to S4 in Example 2, and specifically includes the following steps:

[0120] S1. Sandblasting was performed using 60# sand at 0.6MPa, followed by sandblasting using 120# corundum sand at 0.4MPa, and ultrasonic cleaning was performed using anhydrous ethanol for 10min;

[0121] S2. The Si layer was deposited using PS-PVD technology with a spray distance of 500 mm, a spray temperature of 650–800°C, a spray gun speed of 450 mm / s, a spray current of 1550 A, an argon flow rate of 120 NLPM (standard liters per minute), and a hydrogen flow rate of 7 NLPM.

[0122] S3. Preparation of Yb2Si2O7 layer, spraying distance is 900mm, spraying temperature is controlled between 900 and 1100℃, spraying gun travel is 750mm / s, spraying current is controlled at 2500A, argon flow rate is 110NLPM, helium flow rate is 25NLPM;

[0123] S4. After spraying the Yb2Si2O7 layer, remove the sample and keep it in an air atmosphere at 1300°C for 3 hours at a heating and cooling rate of 5°C / min to obtain the target thermal barrier coating.

[0124] Performance Testing

[0125] The thermal barrier coatings prepared in Example 2 and Comparative Example 2 were subjected to water-oxygen corrosion tests in a 1400°C water-oxygen environment. The experimental conditions were: atmospheric atmosphere, a 1700X tube furnace was used to control the sample temperature to 1400°C ± 2°C, a 1600°C thermocouple was used to measure the temperature and adjust the tube furnace set temperature through feedback, a water vapor flow rate of 23.2g / min, introduced from one side of the tube furnace, and the other side of the tube furnace was open to the atmosphere. The water-oxygen corrosion time was 50h. After the water-oxygen corrosion, the cross section was observed, and the test results were as follows: Figure 3 and Figure 4 As shown, the thickness of the remaining Yb2Si2O7 layer and the thickness of the thermally grown oxide of the Si layer were tested, and the test results were filled in Table 2.

[0126] Table 2

[0127] Depend on Figure 3 、 Figure 4 From the test results in Table 2, it can be seen that the surface of the Yb2Si2O7 layer in Comparative Example 2 is significantly corroded and the surface flatness decreases; the remaining thickness of the Yb2Si2O7 layer in Example 2 is significantly higher than that in Comparative Example 2, and the thickness of the thermally grown oxide of the Si layer in Example 2 is significantly lower than that in Comparative Example 2, indicating that the high-entropy ceramic layer with a feather-like structure can effectively protect the Yb2Si2O7 layer, thereby reducing the corrosion of the Yb2Si2O7 layer and the Si layer in a high-temperature water-oxygen environment.

[0128] Example 3

[0129] This embodiment is used to illustrate the thermal barrier coating and its preparation method disclosed in the present invention, including the following steps:

[0130] S1. Sandblasting was performed using 60# sand at 0.6MPa, followed by sandblasting using 120# corundum sand at 0.4MPa, and ultrasonic cleaning was performed using anhydrous ethanol for 10min;

[0131] S2. The Si layer was deposited using PS-PVD technology with a spray distance of 500 mm, a spray temperature of 650–800°C, a spray gun speed of 500 mm / s, a spray current of 1600 A, argon at 115 NLPM (standard liters per minute), and hydrogen at 5 NLPM.

[0132] S3. Preparation of Yb2Si2O7 layer, spraying distance is 900mm, spraying temperature is controlled between 900 and 1100℃, spraying gun travel is 700mm / s, spraying current is controlled at 2550A, argon flow rate is 95NLPM, helium flow rate is 30NLPM;

[0133] S4. After spraying the Yb2Si2O7 layer, remove the sample and keep it in an air atmosphere at 1300°C for 3 hours at a heating and cooling rate of 5°C / min;

[0134] S5. Prepared by PS-PVD technology (Y 0.2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2) 2Zr2O7 high entropy ceramic layer, the spraying distance is controlled at 1000mm, the spraying temperature is controlled at 900~1100℃, the spraying gun speed is 400mm / s, the current is controlled at 2550A, the argon flow rate is 40NLPM, and the helium flow rate is 70NLPM to obtain the target thermal environment barrier coating.

[0135] Comparative Example 3

[0136] This comparative example is used to illustrate the thermal barrier coating and its preparation method disclosed in the present invention. The preparation method is the implementation steps of Example 3 except for the preparation of the high entropy ceramic layer, that is, S1 to S4 in Example 3, and specifically includes the following steps:

[0137] S1. Sandblasting was performed using 60# sand at 0.6MPa, followed by sandblasting using 120# corundum sand at 0.4MPa, and ultrasonic cleaning was performed using anhydrous ethanol for 10min;

[0138] S2. The Si layer was deposited using PS-PVD technology with a spray distance of 500 mm, a spray temperature of 650–800°C, a spray gun speed of 500 mm / s, a spray current of 1600 A, argon at 115 NLPM (standard liters per minute), and hydrogen at 5 NLPM.

[0139] S3. Preparation of Yb2Si2O7 layer, spraying distance is 900mm, spraying temperature is controlled between 900 and 1100℃, spraying gun travel is 700mm / s, spraying current is controlled at 2550A, argon flow rate is 95NLPM, helium flow rate is 30NLPM;

[0140] S4. After spraying the Yb2Si2O7 layer, remove the sample and keep it in an air atmosphere at 1300°C for 3 hours at a heating and cooling rate of 5°C / min to obtain the target thermal barrier coating.

[0141] Performance Testing

[0142] The thermal barrier coatings prepared in Example 3 and Comparative Example 3 were subjected to water-oxygen corrosion tests in a 1400°C water-oxygen environment. The experimental conditions were: atmospheric atmosphere, a 1700X tube furnace was used to control the sample temperature to 1400°C ± 2°C, a 1600°C thermocouple was used to measure the temperature and feedback to adjust the tube furnace set temperature, a water vapor flow rate of 23.2g / min, introduced from one side of the tube furnace, and the other side of the tube furnace was open to the atmosphere. The water-oxygen corrosion time was 150h. After the water-oxygen corrosion, the cross-section was observed, and the test results were as follows: Figure 5 and Figure 6 As shown, the thickness of the remaining Yb2Si2O7 layer and the thickness of the thermally grown oxide of the Si layer were tested, and the test results were filled in Table 3.

[0143] Table 3

[0144] Depend on Figure 5 、 Figure 6 From the test results in Table 3, it can be seen that the surface of the Yb2Si2O7 layer in Comparative Example 3 is significantly corroded and the surface flatness decreases; the remaining thickness of the Yb2Si2O7 layer in Example 3 is significantly higher than that in Comparative Example 3, and the thickness of the thermally grown oxide of the Si layer in Example 3 is significantly lower than that in Comparative Example 3, indicating that the high-entropy ceramic layer with a feather-like structure can effectively protect the Yb2Si2O7 layer, thereby reducing the corrosion of the Yb2Si2O7 layer and the Si layer in a high-temperature water-oxygen environment.

[0145] Example 4

[0146] This embodiment is used to illustrate the thermal barrier coating and its preparation method disclosed in the present invention, including the following steps:

[0147] S1. Sandblasting was performed using 60# sand at 0.6MPa, followed by sandblasting using 120# corundum sand at 0.4MPa, and ultrasonic cleaning was performed using anhydrous ethanol for 10min;

[0148] S2. The Si layer was deposited using PS-PVD technology with a spray distance of 470 mm, a spray temperature of 650–800°C, a spray gun speed of 470 mm / s, a spray current of 1650 A, an argon flow rate of 100 NLPM (standard liters per minute), and a hydrogen flow rate of 5 NLPM.

[0149] S3. Preparation of Yb2Si2O7 layer with a spray distance of 1000 mm, a spray temperature of 900-1000°C, a spray speed of 700 mm / s, a spray current of 2400 A, an argon flow rate of 95 NLPM, and a helium flow rate of 30 NLPM.

[0150] S4. After spraying the Yb2Si2O7 layer, remove the sample and keep it in an air atmosphere at 1300°C for 3 hours at a heating and cooling rate of 5°C / min;

[0151] S5. Prepared by PS-PVD technology (Y 0.2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 ) 2Zr2O7 high entropy ceramic layer, the spraying distance is controlled at 950mm, the spraying temperature is controlled at 900~1100℃, the spraying gun travel speed is 450mm / s, the current is controlled at 2550A, the argon flow rate is 40NLPM, and the helium flow rate is 70NLPM to obtain the target thermal environment barrier coating.

[0152] Comparative Example 4

[0153] This comparative example is used to illustrate the thermal barrier coating and its preparation method disclosed in the present invention. The preparation method is the implementation steps of Example 4 except for the preparation of the high entropy ceramic layer, i.e., S1 to S4 in Example 4, and specifically includes the following steps:

[0154] S1. Sandblasting was performed using 60# sand at 0.6MPa, followed by sandblasting using 120# corundum sand at 0.4MPa, and ultrasonic cleaning was performed using anhydrous ethanol for 10min;

[0155] S2. The Si layer was deposited using PS-PVD technology with a spray distance of 470 mm, a spray temperature of 650–800°C, a spray gun speed of 470 mm / s, a spray current of 1650 A, an argon flow rate of 100 NLPM (standard liters per minute), and a hydrogen flow rate of 5 NLPM.

[0156] S3. Preparation of Yb2Si2O7 layer with a spray distance of 1000 mm, a spray temperature of 900-1000°C, a spray speed of 700 mm / s, a spray current of 2400 A, an argon flow rate of 95 NLPM, and a helium flow rate of 30 NLPM.

[0157] S4. After spraying the Yb2Si2O7 layer, remove the sample and keep it in an air atmosphere at 1300°C for 3 hours at a heating and cooling rate of 5°C / min to obtain the target thermal barrier coating.

[0158] Performance Testing

[0159] 1. The thermal barrier coatings prepared in Example 4 and Comparative Example 4 were subjected to water-oxygen corrosion tests in a 1400°C water-oxygen environment. The experimental conditions were: atmospheric atmosphere, a 1700X tube furnace was used to control the sample temperature to 1400°C ± 2°C, a 1600°C thermocouple was used to measure the temperature and adjust the tube furnace set temperature, a water vapor flow rate of 23.2 g / min was introduced from one side of the tube furnace, and the other side of the tube furnace was open to the atmosphere, and the water-oxygen corrosion time was 300 hours. After the water-oxygen corrosion, the cross section was observed, and the test results were as follows: Figure 7 and Figure 8 As shown, the thickness of the remaining Yb2Si2O7 layer and the thickness of the thermally grown oxide of the Si layer were tested, and the test results were filled in Table 4.

[0160] Table 4

[0161] Depend on Figure 7 、 Figure 8From the test results in Table 4, it can be seen that the surface of the Yb2Si2O7 layer in Comparative Example 4 is significantly corroded and the surface flatness decreases; the remaining thickness of the Yb2Si2O7 layer in Example 4 is significantly higher than that in Comparative Example 4, and the thickness of the thermally grown oxide of the Si layer in Example 4 is significantly lower than that in Comparative Example 4, indicating that the high-entropy ceramic layer with a feather-like structure can effectively protect the Yb2Si2O7 layer, thereby reducing the corrosion of the Yb2Si2O7 layer and the Si layer in a high-temperature water-oxygen environment.

[0162] 2. The thickness of thermally grown oxide of Si layer obtained by the above Examples 2 to 4 and Comparative Examples 2 to 4 is plotted to obtain the following results: Figure 8 As shown, TEBC is the test results of Examples 2 to 4, and EBC is the test results of Comparative Examples 2 to 4.

[0163] Depend on Figure 8 The test results show that the thermal environment barrier coating provided by the present invention has a good high-temperature water and oxygen barrier effect, effectively delays the growth of thermally grown oxides in the Si layer, and is beneficial to improving the service life of SiC components in high-temperature water and oxygen environments.

[0164] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A thermal barrier coating, characterized in that: The high strain tolerance layer comprises a dense layer and a high strain tolerance layer, wherein the dense layer is a rare earth silicate, the high strain tolerance layer is a high entropy ceramic, the high strain tolerance layer comprises a plurality of feather columnar structures arranged on the surface of the dense layer, the feather columnar structures are composed of the high entropy ceramic, and the high entropy ceramic is (Y 0.2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 )2Zr2O7.

2. The thermal barrier coating according to claim 1, characterized in that: The rare earth silicate includes one or more of rare earth monosilicates and rare earth disilicates, and the rare earth elements of the rare earth silicate include one or more of ytterbium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, yttrium and erbium.

3. The thermal barrier coating according to claim 1 or 2, characterized in that: The rare earth silicate is selected from rare earth double silicate, and the rare earth double silicate includes Yb2Si2O7.

4. The thermal barrier coating according to claim 1, characterized in that: The thickness of the dense layer is 75-200 μm, and / or The thickness of the high strain tolerance layer is 150-300 μm.

5. The thermal barrier coating according to claim 1, wherein: The invention also includes a Si layer, which is used for contacting the substrate. The Si layer is located on a side of the dense layer away from the high strain tolerance layer, and the thickness of the Si layer is 50-150 μm.

6. A high temperature resistant component, characterized in that: The thermal barrier coating comprises a substrate and the thermal barrier coating according to any one of claims 1 to 5 arranged on the substrate, wherein the substrate is selected from SiC.

7. The method for preparing a thermal barrier coating according to any one of claims 1 to 5, wherein: The steps are as follows: Using rare earth silicates as raw materials for the deposition of dense layers; A high entropy ceramic is deposited on the surface of the dense layer to form a high strain tolerance layer.

8. The method for preparing a thermal barrier coating according to claim 7, wherein: Also includes: SiC is used as a substrate, a Si layer is deposited on the substrate, and the dense layer is formed on the Si layer.

9. The method for preparing a thermal barrier coating according to claim 8, wherein: The Si layer, the dense layer and the high strain tolerance layer are all prepared by PS-PVD technology; The PS-PVD preparation parameters of the Si layer are: spray current of 1500-1700A, argon flow rate of 100-120 NLPM (standard liters per minute), hydrogen flow rate of 4-7 NLPM (standard liters per minute), and chamber pressure of 35-50 mbar; and / or The PS-PVD preparation parameters of the dense layer are: spraying current of 2400-2600A, argon flow rate of 90-110 NLPM (standard liters per minute), helium flow rate of 15-30 NLPM (standard liters per minute), and chamber pressure of 1.2-2.0 mbar; and / or The PS-PVD preparation parameters of the high strain tolerance layer are: current controlled at 2400-2600A, argon flow rate at 25-45 NLPM (standard liters per minute), and helium flow rate at 50-70 NLPM (standard liters per minute); and / or After the dense layer is sprayed, the sprayed dense layer is heat treated at a temperature of 1250-1350° C. and for a time of 2-10 hours.

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