High performance composite structure high entropy thermal / environmental barrier coating and method of making same

Abstract

The application provides a high-performance composite structure high-entropy thermal / environment barrier coating and a preparation method thereof, relates to the technical field of high-temperature protection coatings of an aero-engine, and the coating comprises a composite bonding layer, an EBC double intermediate layer and a TBC top layer which are sequentially located on the interface of a base material; the composite bonding layer is a layered stack structure and is made of Si-HfO2; the EBC double intermediate layer is a dense layered stack structure and is made of Yb2Si2O7 and (Yb 0.8 Lu 0.2 )2SiO5; and the TBC top layer is a feather-columnar structure and is made of a defective fluorite-type high-entropy hafnate with a chemical general formula of (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 )2Hf2O7. The coating has good resistance to various corrosive media in the turbine and can effectively improve the temperature bearing capacity and service life of the turbine of the engine.

Description

Technical Field

[0001] This invention relates to the field of high-temperature protective coating technology for aero-engines, specifically to a high-performance composite high-entropy thermal / environmental barrier coating and its preparation method. Background Technology

[0002] With the rapid development of aero engines towards higher thrust-to-weight ratios, increasing the turbine inlet temperature has become a key factor determining engine performance. Modern advanced aero engines require turbine inlet temperatures exceeding 1750°C. Under this harsh temperature environment, even with advanced film cooling technology and thermal barrier coating (TBC) protection, the maximum operating temperature of traditional nickel-based superalloys is still limited to below 2000K.

[0003] Compared with traditional nickel-based superalloys, SiC f SiC ceramic matrix composites (CMCs) possess significant advantages: their density is only one-third that of nickel-based alloys, their specific strength is increased by more than 40%, and their long-term service temperature can reach 1200℃; they also exhibit better creep resistance and a lower coefficient of thermal expansion (CTE). These properties make them the most promising candidate materials for hot-section components of next-generation high thrust-to-weight ratio aero-engines (such as turbine blades, combustion chamber liners, and guide vanes). However, in actual service, SiC... f / SiC materials face severe environmental challenges: in high-temperature and high-pressure gas environments, the material surface reacts with the high-speed flowing gas, leading to the formation and volatilization of the protective SiO2 layer; at the same time, CMAS (CaO-MgO-Al2O3-SiO2) molten salt drawn in at the turbine hot end will penetrate into the material at high temperatures, causing severe corrosion damage.

[0004] To address these challenges, Environmental Barrier Coating (EBC) technology has emerged and continues to evolve. Current fourth-generation T / EBC systems achieve both thermal and environmental protection through a multi-layered design. A typical modern T / EBC system comprises four layers: the top layer uses modified yttrium-stabilized zirconium oxide (YSZ) or novel rare-earth zirconates (such as Gd₂Zr₂O₇) to provide thermal insulation and resistance to CMAS corrosion; the two intermediate layers use rare-earth silicates such as Yb₂SiO₅ / Yb₂Si₂O₇ to resist corrosion in water-oxygen environments; and the bottom layer achieves good bonding with the substrate through a Si bonding layer.

[0005] Although the current T / EBC multilayer coating system design provides resistance to various corrosive media and solves the protection requirements to a certain extent, it has serious peeling failure problems under the actual high temperature thermal cycling conditions of aero engines. The main problems are: (1) The maximum operating temperature of the traditional Si adhesive layer is limited to below 1300℃, and thermally grown oxide (TGO) of cristobalite will be generated during long-term service. The volume change and the sudden change of thermal expansion coefficient before and after the β→α phase transformation of cristobalite in the 200-275℃ range all lead to repeated accumulation of thermal stress inside the coating, which eventually causes the adhesive layer / intermediate layer interface to peel off, causing the upper functional layer to fail prematurely. (2) The existing top TBC layer has a high thermal expansion coefficient and there is a significant difference in thermal expansion coefficient between it and the substrate. Under thermal cycling conditions at 1500℃, this mismatch leads to thermal stress concentration within the coating, inducing the propagation of vertical cracks within the top layer or the appearance of transverse cracks at the interlayer interface. This provides a rapid diffusion path for corrosive media and increases the risk of spalling. Therefore, many current EBC coatings or T / EBC coatings struggle to overcome the bottleneck of long-term thermal cycling at 1500℃ under non-active cooling conditions. Furthermore, to improve the engine's heat resistance at the hot end, the thermal insulation capacity of the top-layer TBC material, which isolates the high-temperature flame, needs further improvement.

[0006] In summary, the synergistic effect of the above problems results in a low average lifespan of the existing T / EBC system at 1500℃, which cannot meet the long service life requirements of the new generation of engines. There is an urgent need to design a new T / EBC coating that can meet higher service temperatures and longer service life. Summary of the Invention

[0007] In view of this, this application provides a high-performance composite high-entropy thermal / environmental barrier coating and its preparation method, based on new material systems and composite coating structure design, aiming to improve the service life of ceramic matrix composites in high-temperature extreme environments. This technological breakthrough will have a significant impact on improving the thrust-to-weight ratio and reliability of aero-engines, and has important engineering application value and strategic significance.

[0008] This application provides the following technical solution: a high-performance composite structure high-entropy thermal / environmental barrier coating, comprising: a composite adhesive layer, an EBC double intermediate layer, and a TBC top layer sequentially located on the interface of the substrate material;

[0009] The composite adhesive layer has a layered stacked structure and is made of Si-HfO2; the EBC double intermediate layer has a dense layered stacked structure, including an EBC first intermediate layer made of Yb2Si2O7 and an EBC intermediate layer made of (Yb 0.8 Lu 0.2The second intermediate layer of the EBC is 2SiO5; the top layer of the TBC has a feather-column structure and is made of defect fluorite-type high-entropy hafnium salt with the general chemical formula (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 )2Hf2O7.

[0010] With the increasing service temperature and lifespan of hot-end components in high thrust-to-weight ratio aero-engines, the development of T / EBC coatings not only needs to consider their corrosion resistance but also their temperature resistance and high-temperature thermal cycling life. This requires designing T / EBC coatings with superior thermal insulation and better matching interlayer CTE. Therefore, this invention proposes a high-performance composite high-entropy thermal / environmental barrier coating, comprising a feather-column TBC top layer, a dense EBC double intermediate layer with better CTE matching, and a composite bonding layer to prevent TGO phase transition peeling, thus addressing the aforementioned technical problems.

[0011] The material composition of the top layer of the aforementioned TBC is defective fluorite type (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 High-entropy hafnium salt (Hf₂O₇) exhibits excellent resistance to CMAS corrosion. This material, through oxygen vacancy defects and high-entropy lattice distortion, increases phonon relaxation time and reduces lattice thermal conductivity, thus providing good thermal insulation. Furthermore, the doping of small-radius multi-component rare-earth elements weakens lattice anharmonic vibrations and lowers chemical bond energies, resulting in a low CTE, ensuring CTE matching with other layers and the substrate. In addition, the feather-column structure design fully utilizes the strain damage tolerance enhancement effect imparted by the columnar crystal structure, preventing interlayer spalling failure caused by thermal stress accumulation in conventional dense TBC top layers during high-temperature thermal cycling. Moreover, the feather-like polycrystalline stacking structure between the columnar crystals delays the intrusion of external corrosive media, thereby improving corrosion resistance.

[0012] The material composition of the above-mentioned double EBC interlayer is (Yb 0.8 Lu 0.2 )2SiO5 modified monosilicate and Yb2Si2O7 bissilicate. (Yb 0.8 Lu 0.2 Compared to Yb₂SiO₅ monosilicate, 2SiO₅ modified monosilicate has a lower CTE, which can effectively improve the CTE matching degree between layers, thereby extending the high-temperature thermal cycling service life of T / EBC. In addition, the dense structure can effectively enhance the penetration of external water and oxygen corrosive media into the EBC intermediate layer, providing long-term protection against oxidation and failure of the underlying adhesive layer and substrate.

[0013] The composite adhesive layer described above is composed of Si-10 mol% HfO2. The doping of refractory HfO2 can increase the service temperature of the Si adhesive layer. Furthermore, at high temperatures, HfO2 reacts chemically with cristobalite (TGO) to form a dispersed, toughened HfSiO4 phase, which effectively extends the crack propagation path within the layer and prolongs the high-temperature thermal cycling service life of the adhesive layer. It is worth noting that the HfO2 content in the composite adhesive layer needs to be controlled between 8-15 mol%. If the HfO2 content is too low, it will not provide a significant benefit; if it is too high, it will cause mismatch with the substrate CTE, resulting in interfacial peeling. Based on previous research on different HfO2 content designs and their resistance to high-temperature thermal cycling, this invention preferably uses a 10 mol% HfO2 content to ensure both increased service temperature and extended service life.

[0014] The novel coating of this invention improves the thermal performance and phase change resistance of the adhesive layer, optimizes the CTE matching between layers, reduces the thermal conductivity of the top layer material, and enhances the thermal insulation performance of the top layer.

[0015] According to one embodiment of the present invention, the molar content of HfO2 in the composite adhesive layer is 8-15%; preferably 10%.

[0016] According to one embodiment of the present invention, the porosity of the first intermediate layer and the second intermediate layer of the EBC is less than 10%.

[0017] According to one embodiment of the present invention, the total thickness of the coating is 300~450 μm; wherein, the thickness of the composite adhesive layer is 30~70 μm; the thickness of the first EBC intermediate layer is 100~140 μm; the thickness of the second EBC intermediate layer is 40~60 μm; and the thickness of the TBC top layer is 120~160 μm.

[0018] According to one embodiment of the present invention, the matrix material is SiC. f / SiC ceramic matrix composites.

[0019] This invention also provides a method for preparing a high-performance composite high-entropy thermal / environmental barrier coating, comprising the following steps: preparing a composite bonding layer Si-HfO2, a first EBC intermediate layer Yb2Si2O7, and a second EBC intermediate layer (Yb2Si2O7) sequentially on the surface of a substrate material using low-pressure plasma spraying. 0.8 Lu 0.2 The prepared coating was subjected to vacuum annealing; then, a TBC top layer (Dy) was prepared on the annealed coating surface by plasma spraying-physical vapor deposition. 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu0.2 The high-entropy thermal / environmental barrier coating is obtained by reacting 2Hf2O7 with Hf2O7.

[0020] According to one embodiment of the present invention, the process parameters for preparing the composite adhesive layer by the low-pressure plasma spraying include: current: 1600~1700 A; Ar flow rate: 110 NLPM, H2 flow rate: 6 NLPM; powder feed rate: 7.0~9.4 g / min; spray distance: 350 mm; preheating temperature: 700~800℃; pressure: 40 mbar.

[0021] According to one embodiment of the present invention, the process parameters of the vacuum annealing treatment include: heating rate: 3℃ / min; holding temperature: 1250~1350℃; holding time: 2.5~3.5h; cooling rate: 2℃ / min.

[0022] According to one embodiment of the present invention, the process parameters for preparing the TBC top layer by plasma spraying-physical vapor deposition include: current: 2500~2700 A; Ar flow rate: 35 NLPM, He flow rate: 55~65 NLPM; powder feed rate: 8.0~12.0 g / min; spray distance: 1000 mm; preheating temperature: 900~1000℃; pressure: 0.5 mbar.

[0023] This invention conducts in-depth research from multiple dimensions, including material system innovation, coating structure optimization, and preparation process improvement. Specifically, in terms of coating materials, novel materials with higher phase stability and lower thermal conductivity have been developed; in terms of coating structure design, the CTE matching problem between multilayer materials has been solved; and in terms of preparation processes, advanced technologies capable of precisely controlling the microstructure of the coating have been explored. Compared with existing technologies, the beneficial effects achievable by at least one of the above-mentioned technical solutions adopted in the embodiments of this specification include at least the following: Feather-columnar defect fluorite type (Dy) in the embodiments of the present invention 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 The 2Hf2O7 high-entropy hafnium salt TBC top layer not only has low thermal conductivity and CTE, thus improving the overall temperature resistance of the coating and the degree of CTE matching between layers, but also the feather-column coating structure design can further improve the high-temperature thermal cycling service life of the coating.

[0024] This invention selects dense type (Yb) 0.8 Lu 0.2 The 2SiO5 modified monosilicate EBC intermediate layer can ensure resistance to water and oxygen corrosion, while the low CTE characteristics further improve the CTE matching of each layer, thereby improving the overall service life of the coating.

[0025] The dense Si-HfO2 composite adhesive layer selected in this invention can not only increase the service temperature of the adhesive layer, but also avoid the interlayer peeling problem caused by TGO phase transformation, thereby improving the overall service life of the coating.

[0026] The coating preparation technology selected in this invention is simple, the conditions are controllable, and it is easy to achieve industrial-scale preparation.

[0027] In summary, the present invention provides a (Dy) structure with the aforementioned feather-column / dense structural characteristics. 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 )2Hf2O7 / (Yb 0.8 Lu 0.2 The 2SiO5 / Yb2Si2O7 / Si-HfO2 thermal / environmental barrier coating not only has good resistance to various corrosive media in turbines, but also has an overall temperature resistance of up to 1500℃ and a service life of up to 200 hours. Using it as a protective coating for the hot end components of ceramic matrix composites in aero-engines can effectively improve the temperature resistance and service life of engine turbines. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in 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.

[0029] Figure 1 This is a flowchart illustrating the design process of the high-entropy thermal / environmental barrier coating for the high-performance composite structure (feather-columnar / dense type) of this invention. Figure 2 This is a cross-sectional morphology diagram of the high-performance composite structure (feather-columnar / dense type) high-entropy thermal / environmental barrier coating obtained in Embodiment 2 of the present invention; Figure 3 The top feather-column high entropy (Dy) in the coating obtained in Example 2 of this invention 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 )2Hf2O7 layer cross-sectional morphology diagram; Figure 4 These are the interface bonding morphology diagrams of each layer in the coating obtained in Embodiment 2 of the present invention; Figure 5 This is a topographic image of the interface between the coating and the substrate obtained in Embodiment 2 of the present invention. Detailed Implementation

[0030] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0031] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] The relevant terms (in Chinese and English) involved in this invention and their explanations are as follows: Ceramic matrix composites: High-performance composite materials formed by adding reinforcing phases (such as carbon fibers, SiC fibers, etc.) to ceramic as the matrix.

[0033] Coefficient of thermal expansion: the rate at which a material's dimensions change when its temperature changes, usually expressed as the rate of change of length or volume per unit temperature change.

[0034] Thermal barrier coating: A heat-insulating coating applied to the surface of high-temperature alloys or ceramic matrix composites to reduce the substrate temperature and improve the high-temperature resistance of components.

[0035] Environmental barrier coating: A protective coating applied to the surface of ceramic matrix composites, mainly used to resist environmental erosion such as high-temperature water vapor, molten salt, and corrosive gases.

[0036] Thermally grown oxides: In thermal barrier coatings and environmental barrier coating systems, TGO usually refers to the oxide layer that gradually forms between the adhesive layer and the top ceramic layer under high-temperature service conditions. Its growth behavior directly affects the service life of the coating.

[0037] CMAS: Alkaline melt formed by the melting of dust, volcanic ash, or runway particles in the air at high temperatures (usually >1200℃). It is a typical corrosive medium encountered by hot-end components of aero engines and gas turbines during high-temperature service. It is composed of CaO, MgO, Al2O3, and SiO2.

[0038] Quadrilateral quartz: It is a crystal form of silicon dioxide (SiO2), belonging to the tetragonal crystal system (high temperature type, β-quadrilateral quartz) or the cubic crystal system (low temperature type, α-quadrilateral quartz), and β-quadrilateral quartz exists during heating / cooling. α-Cadastospheric phase transition.

[0039] Defective fluorite-type high-entropy hafnium salt: a novel high-entropy ceramic material formed by the solid solution of various rare earth cations (such as Dy, Ho, Er, Tm, Lu, etc.) in the hafnium salt fluorite structure, and containing oxygen vacancy defects.

[0040] Feather-columnar structure: A special coating microstructure composed of slender columnar crystals and feather-like branches, commonly found in coatings prepared by plasma spraying-physical vapor deposition.

[0041] Low-pressure plasma spraying: A plasma spraying technology performed in a low-pressure environment (vacuum or inert gas protection). Its core principle is to reduce the oxidation of the sprayed material by oxygen through a vacuum or inert gas environment (such as argon), while simultaneously lowering the ambient pressure, resulting in a longer and more stable plasma jet and higher velocity of the molten particles. Because plasma energy is more concentrated in a low-pressure environment, the sprayed material (such as metals, alloys, or ceramics) can melt more fully, forming a denser, low-porosity coating after deposition.

[0042] Vacuum annealing is a technique that heats materials in a vacuum or low-oxygen partial pressure environment, primarily used to eliminate internal stress, improve microstructure, or enhance material properties. For plasma-sprayed coatings, vacuum annealing can further seal pores, promote diffusion bonding between the coating and the substrate, and improve the coating's density and mechanical properties.

[0043] Plasma spraying-physical vapor deposition (PS-PVD) is an advanced coating technology combining plasma spraying and physical vapor deposition, enabling the deposition of complex structures (such as feather-column structures) at relatively low temperatures. Its principle involves partially evaporating the coating material into a gaseous phase using high-energy plasma. Subsequently, under low pressure, gaseous atoms or molecules are deposited onto the substrate surface in a directional flow. Because gas transport dominates the deposition process, the coating growth mechanism is similar to PVD, allowing for the formation of nanoscale columnar or feather-like structures. Simultaneously, residual molten droplets create micron-level features, enabling multi-scale structural control. PS-PVD's unique advantages lie in its high deposition rate and adaptability to complex shapes, making it suitable for preparing high-performance coatings for applications such as aero-engine blades and fuel cell electrolytes.

[0044] This invention proposes a high-performance composite high-entropy thermal / environmental barrier coating, the coating structure and system of which, from top to bottom, include a feather-column (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 )2Hf2O7 top layer, dense type (Yb 0.8 Lu 0.2 The structure consists of a 2SiO5 interlayer, a dense Yb2Si2O7 interlayer, a dense Si-HfO2 composite bonding layer, and a SiC layer.f / SiC matrix.

[0045] The aforementioned high entropy (Dy) 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 The 2Hf2O7 material possesses a defective fluorite crystal structure, a low coefficient of thermal expansion that better matches the matrix, and low thermal conductivity for superior thermal insulation performance. Furthermore, the feather-column structure design further enhances the stress damage tolerance of the top layer and improves the coating's thermal insulation capability while ensuring corrosion resistance.

[0046] The above (Yb) 0.8 Lu 0.2 Compared to traditional Yb2SiO5 materials, the Yb2SiO5 intermediate layer not only has improved resistance to water and oxygen corrosion, but also has a lower coefficient of thermal expansion, which can further improve the thermal expansion matching between multiple T / EBC layers, thereby extending the overall high-temperature thermal cycle service life.

[0047] The HfO2 content in the above-mentioned composite adhesive layer is preferably 10 mol%, which can give full play to HfO2's ability to improve the temperature resistance of the adhesive layer, weaken the TGO phase transformation and disperse toughening ability, and avoid the thermal expansion mismatch problem caused by excessive HfO2.

[0048] The above T / EBC in SiC f The preparation technology and sequence of the / SiC surface are as follows: A Si-HfO2 composite bonding layer, a Yb2Si2O7 intermediate layer, and a (Yb2HfO2) composite bonding layer are prepared sequentially using low-pressure plasma spraying. 0.8 Lu 0.2 )2SiO5 intermediate layer, prepared by plasma spraying-physical vapor deposition after vacuum annealing (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 The top layer is 2Hf2O7. In each layer of T / EBC, the thickness of the top layer can be 120~160μm, the overall thickness of the double intermediate layer can be 150~200μm, and the thickness of the adhesive layer can be 30~70μm.

[0049] In an optional embodiment, a dense Si-HfO2 bonding layer, a Yb2Si2O7 interlayer, and a (Yb2HfO2)-HfO2 interlayer are prepared using low-pressure plasma spraying technology. 0.8 Lu 0.2)2SiO5 intermediate layer. The process parameters for preparing the Si-HfO2 binder layer include: working current of 1600-1700 A (e.g., 1600 A, 1650 A or 1700 A), Ar flow rate of 110 NLPM, H2 flow rate of 6 NLPM, powder feed rate of 7.0-9.4 g / min (e.g., 7.0 g / min, 8.2 g / min or 9.4 g / min), spray gun speed of 550 mm / s, 8 spray passes, spray distance of 350 mm, preheating temperature of 700-800℃ (e.g., 700℃, 750℃ or 800℃), and pressure of 40 mbar. The process parameters for preparing the Yb2Si2O7 intermediate layer include: operating current of 2540-2660 A (e.g., 2540 A, 2600 A, or 2660 A), Ar flow rate of 100 NLPM, He flow rate of 20 NLPM, powder feed rate of 16-24 g / min (16 g / min, 20 g / min, or 24 g / min), spray gun speed of 550 mm / s, 30 coats, spray distance of 950 mm, preheating temperature of 950-1050℃ (e.g., 950℃, 1000℃, or 1050℃), and pressure of 1.5 mbar. (Yb 0.8 Lu 0.2 The process parameters for preparing the SiO5 intermediate layer include: operating current of 2540-2660 A (e.g., 2540 A, 2600 A, or 2660 A), Ar flow rate of 100 NLPM, He flow rate of 20 NLPM, powder feed rate of 16-24 g / min (16 g / min, 20 g / min, or 24 g / min), spray gun speed of 550 mm / s, 10 spray passes, spray distance of 950 mm, preheating temperature of 650-750℃ (e.g., 650℃, 700℃, or 750℃), and pressure of 1.5 mbar.

[0050] In an optional embodiment, the environmental barrier coating prepared by low-pressure plasma spraying is subjected to stress-relief annealing using vacuum annealing technology. The annealing process parameters are: heating rate 3℃ / min, holding temperature 1250℃-1350℃ (e.g., 1250℃, 1300℃, or 1350℃), holding time 2.5-3.5 h (e.g., 2.5 h, 3 h, or 3.5 h), and cooling to room temperature at a rate of 2℃ / min.

[0051] In an optional embodiment, a plasma spraying-physical vapor deposition technique is used to prepare feather-column (Dy) columns. 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2The top heat insulation layer of 2Hf2O7 has the following preparation process parameters: operating current of 2500-2700 A (e.g., 2500 A, 2600 A, or 2700 A), Ar flow rate of 35 NLPM, He flow rate of 55-65 NLPM (e.g., 55 NLPM, 60 NLPM, or 65 NLPM), powder feed rate of 8.0-12 g / min (e.g., 8.0 g / min, 10.0 g / min, or 12.0 g / min), spray gun speed of 550 mm / s, 70 spray passes, spray distance of 1000 mm, preheating temperature of 900-1000℃ (e.g., 900℃, 950℃, or 1000℃), and pressure of 0.5 mbar.

[0052] It should be noted that any process parameters and conditions not explicitly listed in the above preparation process can be performed with reference to relevant existing technologies, and this application does not impose specific limitations on them. Unless otherwise specified, all reagents, materials, and instruments involved in the implementation process are commercially available, general-purpose products that conform to industry standards.

[0053] As mentioned above, the thermal / environmental barrier coating prepared by the above process has unique feather-column and dense composite structure characteristics. The interfaces of each coating are tightly bonded, and it has the comprehensive advantages of thermal insulation, high strain damage tolerance and corrosion resistance, showing excellent resistance to high temperature thermal cycling.

[0054] Furthermore, this application also provides applications of the aforementioned high-performance composite high-entropy thermal / environmental barrier coating, such as its use as a protective coating on the surface of aero-engine end components. This coating can significantly improve the temperature resistance, high-temperature water-oxygen corrosion resistance, and thermal cycling service life of aero-engine hot-end components.

[0055] The technical features and performance of the high-performance composite high-entropy thermal / environmental barrier coating of the present invention will be described in more detail below with reference to specific embodiments.

[0056] Example 1 like Figure 1 As shown, this embodiment provides a high-performance composite high-entropy thermal / environmental barrier coating and its preparation method, including the following steps: Step S1: Dy₂O₃, Ho₂O₃, Er₂O₃, Tm₂O₃, Lu₂O₃, and HfO₂ powders were dried at 120℃ for 2 hours. Then, the powders were weighed according to a molar ratio of 0.2:0.2:0.2:0.2:0.2:2 and added to a ball mill for wet ball milling to obtain a first mixed slurry. The wet ball milling speed was 600 rpm, the mixing time was 24 hours, and the mass ratio of powder, anhydrous ethanol, and milling beads was 1:0.8:1. Subsequently, the first mixed slurry was dried in air at 80°C for 12 h and then added to a high-temperature muffle furnace for solid-phase reaction at 1550°C for 7 h. Finally, the synthesized powder was mechanically crushed and sieved to obtain the first powder with a median particle size of 5-20 μm.

[0057] In step S2, Yb₂O₃, Lu₂O₃, and SiO₂ powders were dried at 120℃ for 2 hours each. Then, the powders were weighed according to a molar ratio of 0.8:0.2:1 and added to a ball mill for wet ball milling to obtain a second mixed slurry. The wet ball milling speed was 550 rpm, the mixing time was 12 hours, and the mass ratio of powder, anhydrous ethanol, and milling beads was 1:0.85:1.05. Subsequently, the second mixed slurry was dried in air at 80℃ for 12 hours, and then added to a high-temperature muffle furnace for solid-state reaction at 1500℃ for 4 hours. Finally, the synthesized powder was mechanically crushed and sieved to obtain a second powder with a median particle size of 30-50 μm.

[0058] In step S3, Yb₂O₃ powder and SiO₂ powder were dried separately at 120℃ for 4 hours. Then, Yb₂O₃ and SiO₂ powders were weighed at a molar ratio of 1:2 and added to a ball mill for wet ball milling to obtain a third mixed slurry. The wet ball milling speed was 550 rpm, the mixing time was 12 hours, and the mass ratio of powder, anhydrous ethanol, and milling beads was 1:0.85:1.05. The third mixed slurry was then dried at 80℃ in air for 12 hours, and then added to a high-temperature muffle furnace for solid-state reaction at 1500℃ for 4 hours. Finally, the synthesized powder was crushed and sieved to obtain the third powder with a median particle size of 30-50 μm.

[0059] In step S4, Si and HfO2 powders were dried separately at 120℃ for 2 hours. Then, Si and HfO2 powders were weighed at a molar ratio of 90:10 and added to a ball mill for wet ball milling to obtain a fourth mixed slurry. The wet ball milling speed was 600 rpm, the mixing time was 24 hours, and the mass ratio of powder, anhydrous ethanol, and milling beads was 1:0.85:1.05. Subsequently, the fourth mixed slurry was dried in air at 80℃ for 12 hours to obtain the fourth powder.

[0060] Step S5: Add adhesive (purchased from Wuhan Meiqilin New Materials Co., Ltd. MQ-35 series) and solvent (distilled water) to the first, second, third, and fourth powders to prepare a suspension with a solid content of 45-60% for spray granulation. The adhesive addition amount is 4-10%, and the spray granulation process parameters are set as follows: inlet temperature 200-300℃, atomizing disc frequency 20-50 Hz, feed pump speed 30-50 rpm, and outlet temperature 90-130℃, ultimately obtaining a (Dy) powder suitable for thermal spraying. 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 )2Hf2O7,(Yb 0.8 Lu 0.2 2SiO5, Yb2Si2O7 and Si-HfO2 spherical powders.

[0061] Step S6: A 20 mm × 20 mm × 5 mm flat-plate SiC substrate is fabricated by wire EDM. f The SiC substrate was sandblasted using #120 mesh brown corundum abrasive. The spraying parameters were set as follows: sandblasting pressure 0.2 MPa, sandblasting angle 50°, sandblasting distance 120 mm, and sandblasting time 1 min, resulting in an average surface roughness Ra of 5 μm. Subsequently, the substrate was ultrasonically cleaned sequentially with kerosene, acetone, and alcohol, and after drying, it was fixed onto a dedicated spraying fixture.

[0062] Step S7: Using low-pressure plasma spraying technology, the robot arm's motion trajectory and spraying parameters are preset, and Si-HfO2 spherical powder, Yb2Si2O7 spherical powder, and (Yb 0.8 Lu 0.2 Spherical powder of 2SiO5 was used to prepare a Si-HfO2 binder layer of approximately 38 μm, a Yb2Si2O7 interlayer of approximately 109 μm, and a (Yb2Si2O7) interlayer of approximately 42 μm on a substrate that had been sequentially sandblasted. 0.8 Lu 0.2The three-layer environmental barrier coating consists of a Si-HfO2 intermediate layer and a Si-HfO2 binder layer. The spraying process parameters are as follows: current 1600 A, Ar and H2 flow rates of 110 NLPM and 6 NLPM respectively, powder feed rate 7.0 g / min, spray gun speed 550 mm / s, 8 coats, spray distance 350 mm, preheating temperature 700℃, and pressure 40 mbar. The spraying process parameters for the Yb2Si2O7 intermediate layer are as follows: current 2540 A, Ar and He flow rates of 100 NLPM and 20 NLPM respectively, powder feed rate 16 g / min, spray gun speed 550 mm / s, 30 coats, spray distance 950 mm, preheating temperature 950℃, and pressure 1.5 mbar. 0.8 Lu 0.2 The spraying process parameters for the 2SiO5 intermediate layer are as follows: current is 2540 A, flow rates of Ar and He are 100 NLPM and 20 NLPM respectively, powder feed rate is 16 g / min, spray gun speed is 550 mm / s, number of spray passes is 10, spray distance is 950 mm, preheating temperature is 650℃, pressure is 1.5 mbar, and the process maintains a suitable oxygen partial pressure through an oxygen supplementation system to prevent rare earth silicate crystals from losing oxygen.

[0063] Step S8: Using vacuum annealing technology, the above-mentioned coating sample is placed in an alumina crucible and transported to the heating section of a vacuum tube furnace. Before heating, the furnace tube is evacuated three times to remove air, and high-purity argon is introduced for protection to prevent oxidation of the substrate and coating. Then, the sample is heated to 1300°C at 3°C / min and held at that temperature for 3 hours. Subsequently, it is cooled to room temperature at 2°C / min to obtain the stress-relieved coating sample.

[0064] Step S9: Using plasma spraying-physical vapor deposition technology, the robot arm's motion trajectory and spraying parameters are preset, and the powder is conveyed into the powder feeder (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 )2Hf2O7 spherical powder was further used to prepare approximately 130 μm (Dy) on the surface of the stress-relief coating sample. 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2The top insulation layer of 2Hf2O7 has a feather-column structure. The spraying process parameters are as follows: current 2500 A, flow rates of high-purity Ar and He 35 NLPM and 65 NLPM respectively, powder feed rate 8 g / min, spray gun speed 550 mm / s, number of spray passes 70, spray distance 1000 mm, preheating temperature 900℃, and pressure 0.5 mbar.

[0065] Ultimately, a four-layer high-entropy thermal / environmental barrier coating composite coating with both feather-column and dense structures was obtained.

[0066] Example 2 This embodiment provides a high-performance composite high-entropy thermal / environmental barrier coating and its preparation method, including the following steps: Steps S1 to S6 are the same as in Example 1.

[0067] Step S7: Using low-pressure plasma spraying technology, the robot arm's motion trajectory and spraying parameters are preset, and Si-HfO2 spherical powder, Yb2Si2O7 spherical powder, and (Yb 0.8 Lu 0.2 On a substrate treated by sequential sandblasting with a spray gun, a Si-HfO2 binder layer of approximately 44 μm, a Yb2Si2O7 interlayer of approximately 123 μm, and a (Yb2Si2O7) interlayer of approximately 49 μm were prepared using spherical SiO5 powder. 0.8 Lu 0.2 The three-layer environmental barrier coating consists of a Si-HfO2 intermediate layer and a Si-HfO2 binder layer. The spraying process parameters are as follows: current 1650 A, Ar and H2 flow rates of 110 NLPM and 6 NLPM respectively, powder feed rate 8.2 g / min, spray gun speed 550 mm / s, 8 coats, spray distance 350 mm, preheating temperature 750℃, and pressure 40 mbar. The spraying process parameters for the Yb2Si2O7 intermediate layer are as follows: current 2600 A, Ar and He flow rates of 100 NLPM and 20 NLPM respectively, powder feed rate 20 g / min, spray gun speed 550 mm / s, 30 coats, spray distance 950 mm, preheating temperature 1000℃, and pressure 1.5 mbar. 0.8 Lu 0.2 The spraying process parameters for the 2SiO5 intermediate layer are as follows: current is 2600 A, the flow rates of Ar and He are 100 NLPM and 20 NLPM respectively, powder feed rate is 20 g / min, spray gun speed is 550 mm / s, number of spray passes is 10, spray distance is 950 mm, preheating temperature is 700℃, pressure is 1.5 mbar, and the process maintains a suitable oxygen partial pressure through an oxygen supplementation system to prevent rare earth silicate crystals from losing oxygen.

[0068] Step S8: Using vacuum annealing technology, the above-mentioned coating sample is placed in an alumina crucible and transported to the heating section of a vacuum tube furnace. Before heating, the furnace tube is evacuated three times to remove air, and high-purity argon is introduced for protection to prevent oxidation of the substrate and coating. Then, the sample is heated to 1300°C at 3°C / min and held at that temperature for 3 hours. Subsequently, it is cooled to room temperature at 2°C / min to obtain the stress-relieved coating sample.

[0069] Step S9: Using plasma spraying-physical vapor deposition technology, the robot arm's motion trajectory and spraying parameters are preset, and the powder is conveyed into the powder feeder (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 )2Hf2O7 spherical powder was further used to prepare approximately 146 μm of (Dy) on the surface of the stress-relief coating sample. 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 The top insulation layer of 2Hf2O7 has a feather-column structure. The spraying process parameters are as follows: current 2600 A, flow rates of high-purity Ar and He 35 NLPM and 60 NLPM respectively, powder feed rate 10 g / min, spray gun speed 550 mm / s, number of spray passes 70, spray distance 1000 mm, preheating temperature 950℃, and pressure 0.5 mbar.

[0070] Ultimately, a four-layer high-entropy thermal / environmental barrier coating composite coating with both feather-column and dense structures was obtained.

[0071] Example 3 This embodiment provides a high-performance composite high-entropy thermal / environmental barrier coating and its preparation method, including the following steps: Steps S1 to S6 are the same as in Example 1.

[0072] Step S7: Using low-pressure plasma spraying technology, the robot arm's motion trajectory and spraying parameters are preset, and Si-HfO2 spherical powder, Yb2Si2O7 spherical powder, and (Yb 0.8 Lu 0.2 On a substrate treated by sequential sandblasting with a spray gun, a Si-HfO2 binder layer of approximately 53 μm, a Yb2Si2O7 interlayer of approximately 133 μm, and a (Yb2Si2O7) interlayer of approximately 55 μm were prepared using spherical SiO5 powder. 0.8 Lu 0.2The three-layer environmental barrier coating consists of a Si-HfO2 intermediate layer and a Si-HfO2 binder layer. The spraying process parameters are as follows: current 1700 A, Ar and H2 flow rates of 110 NLPM and 6 NLPM respectively, powder feed rate 9.4 g / min, spray gun speed 550 mm / s, 8 coats, spray distance 350 mm, preheating temperature 800℃, and pressure 40 mbar. The spraying process parameters for the Yb2Si2O7 intermediate layer are as follows: current 2660 A, Ar and He flow rates of 100 NLPM and 20 NLPM respectively, powder feed rate 24 g / min, spray gun speed 550 mm / s, 30 coats, spray distance 950 mm, preheating temperature 1050℃, and pressure 1.5 mbar. 0.8 Lu 0.2 The spraying process parameters for the 2SiO5 intermediate layer are as follows: current is 2660 A, flow rates of Ar and He are 100 NLPM and 20 NLPM respectively, powder feed rate is 24 g / min, spray gun speed is 550 mm / s, number of spray passes is 10, spray distance is 950 mm, preheating temperature is 750℃, pressure is 1.5 mbar, and the process maintains a suitable oxygen partial pressure through an oxygen supplementation system to prevent rare earth silicate crystals from losing oxygen.

[0073] Step S8: Using vacuum annealing technology, the above-mentioned coating sample is placed in an alumina crucible and transported to the heating section of a vacuum tube furnace. Before heating, the furnace tube is evacuated three times to remove air, and high-purity argon is introduced for protection to prevent oxidation of the substrate and coating. Then, the sample is heated to 1300°C at 3°C / min and held at that temperature for 3 hours. Subsequently, it is cooled to room temperature at 2°C / min to obtain the stress-relieved coating sample.

[0074] Step S9: Using plasma spraying-physical vapor deposition technology, the robot arm's motion trajectory and spraying parameters are preset, and the powder is conveyed into the powder feeder (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 )2Hf2O7 spherical powder was further used to prepare approximately 160 μm (Dy) on the surface of the stress-relief coating sample. 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2The top insulation layer of 2Hf2O7 has a feather-column structure. The spraying process parameters are as follows: current 2700 A, flow rates of high-purity Ar and He 35 NLPM and 55 NLPM respectively, powder feed rate 12 g / min, spray gun speed 550 mm / s, number of spray passes 70, spray distance 1000 mm, preheating temperature 1000℃, and pressure 0.5 mbar.

[0075] Ultimately, a four-layer high-entropy thermal / environmental barrier coating composite coating with both feather-column and dense structures was obtained.

[0076] Comparative Example 1 This comparative example provides a dense thermal / environmental barrier coating and its preparation method, including the following steps: Steps S1 to S6 are the same as in Example 1.

[0077] Step S7: Using low-pressure plasma spraying technology, the robot arm's motion trajectory and spraying parameters are preset, and Si-HfO2 spherical powder, Yb2Si2O7 spherical powder, and (Yb 0.8 Lu 0.2 )2SiO5 spherical powder and (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 On a substrate treated by sequential sandblasting with a spray gun, a Si-HfO2 binder layer of approximately 45 μm, a Yb2Si2O7 interlayer of approximately 120 μm, and a (Yb2Si2O7) interlayer of approximately 50 μm are prepared using spherical HfO7 powder. 0.8 Lu 0.2 )2SiO5 intermediate layer and 130μm (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 The top insulation layer of 2Hf2O7 consists of four layers of thermal / environmental barrier coatings, all of which are high-density layered stacked structures. The spraying process parameters for the Si-HfO2 binder layer are: current 1650 A, Ar and H2 flow rates of 110 NLPM and 6 NLPM respectively, powder feed rate 8.2 g / min, spray gun speed 550 mm / s, 8 coats, spray distance 350 mm, preheating temperature 750℃, and pressure 40 mbar. The spraying process parameters for the Yb2Si2O7 intermediate layer are as follows: current 2600 A, Ar and He flow rates of 100 NLPM and 20 NLPM respectively, powder feed rate 20 g / min, spray gun speed 550 mm / s, 22 coats, spray distance 950 mm, preheating temperature 1000℃, and pressure 1.5 mbar. (Yb 0.8 Lu0.2 The spraying process parameters for the 2SiO5 intermediate layer are as follows: current of 2600 A, flow rates of Ar and He of 100 NLPM and 20 NLPM respectively, powder feed rate of 20 g / min, spray gun speed of 550 mm / s, number of spray passes of 22, spray distance of 950 mm, preheating temperature of 700℃, and pressure of 1.5 mbar. Furthermore, the process utilizes an oxygen supplementation system to maintain a suitable oxygen partial pressure, preventing oxygen loss from the rare earth silicate crystals. (Dy) 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 The spraying process parameters for the top heat insulation layer of 2Hf2O7 are as follows: current 2600A, flow rates of high-purity Ar and He 35NLPM and 60NLPM respectively, powder feeding rate 20g / min, spraying distance 1000mm, preheating temperature 950℃, and pressure 1.5mbar.

[0078] Performance testing The feather-columnar / dense type (Dy) obtained in the examples 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 )2Hf2O7 / (Yb 0.8 Lu 0.2 The 2SiO5 / Yb2Si2O7 / Si-HfO2 thermal / environmental barrier coating samples were mounted and polished, then magnetron sputtered with gold and placed in a scanning electron microscope to observe the cross-sectional morphology of the coating in backscatter imaging mode. Figures 2 to 5 The backscattered image of the cross-section of the T / EBC coating prepared in Example 2 shows that (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 The top TBC layer of 2Hf2O7 exhibits a feather-columnar structure with a thickness of approximately 146 μm. (Yb 0.8 Lu 0.2 The layers of 2SiO5, Yb2Si2O7, and Si-HfO2 exhibit typical layered, dense stacked structure characteristics, with thicknesses of approximately 49 μm, 123 μm, and 44 μm, respectively. Clear interfaces exist between the coating layers, and they are tightly bonded. The composite adhesive layer shows a distinct interface with the substrate and exhibits good mechanical bonding. Image analysis reveals that (Yb2Si2O7, Yb2Si2O7, and Si-HfO2)... 0.8 Lu 0.2The porosities of the 2SiO5 / Yb2Si2O7 double intermediate layers are 8.6% and 7.5%, respectively, indicating high coating density. Furthermore, the presence of some vertical cracks within the feather-column top layer provides excellent thermal insulation and stress relief characteristics, which is beneficial for improving temperature resistance and high-temperature thermal cycling life.

[0079] All coating samples from the above embodiments and comparative examples were subjected to high-temperature thermal cycling performance testing at 1500℃. The specific testing conditions were as follows: samples were placed in a thermal shock furnace at the target testing temperature, held for 1 hour, and then cooled using a cold air blower, constituting one thermal shock cycle. After 264 cycles, the macroscopic peeling area of ​​the coatings in Examples 1, 2, and 3 was less than 5%, but the microscopic morphology revealed an increase in the number of vertical cracks, indicating impaired corrosion resistance. In the comparative example, under the same high-temperature thermal cycling conditions, after 207 cycles, the macroscopic peeling area reached 20% of the entire surface area, indicating coating failure. This demonstrates that the high-performance composite high-entropy thermal / environmental barrier coating of this invention possesses excellent thermal shock resistance.

[0080] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A high-performance composite high-entropy thermal / environmental barrier coating, characterized in that, include: The composite adhesive layer, EBC double intermediate layer, and TBC top layer are located sequentially on the interface of the matrix material; The composite adhesive layer has a layered stacked structure and is made of Si-HfO2; the EBC double intermediate layer has a dense layered stacked structure, including an EBC first intermediate layer made of Yb2Si2O7 and an EBC intermediate layer made of (Yb 0.8 Lu 0.2 The second intermediate layer of the EBC is 2SiO5; the top layer of the TBC has a feather-column structure and is made of defect fluorite-type high-entropy hafnium salt with the general chemical formula (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 )2Hf2O7; The molar content of HfO2 in the composite adhesive layer is 8-15%; The porosity of the first intermediate layer and the second intermediate layer of the EBC is less than 10%; The total thickness of the coating is 300~450 μm; wherein, the thickness of the composite adhesive layer is 30~70 μm; the thickness of the first EBC intermediate layer is 100~140 μm; the thickness of the second EBC intermediate layer is 40~60 μm; and the thickness of the TBC top layer is 120~160 μm. The method for preparing the high-performance composite high-entropy thermal / environmental barrier coating includes the following steps: The composite bonding layer Si-HfO2, the first EBC intermediate layer Yb2Si2O7, and the second EBC intermediate layer (Yb) were sequentially prepared on the surface of the substrate material using low-pressure plasma spraying. 0.8 Lu 0.2 )2SiO5; The prepared coating was subjected to vacuum annealing; then, a TBC top layer (Dy) was prepared on the annealed coating surface by plasma spraying-physical vapor deposition. 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2 The high-entropy thermal / environmental barrier coating was obtained by reacting 2Hf2O7 with Hf2O7. The process parameters for preparing the TBC top layer using plasma spraying-physical vapor deposition include: current: 2500~2700A; Ar flow rate: 35 NLPM, He flow rate: 55~65 NLPM; powder feed rate: 8.0~12.0 g / min; spray distance: 1000 mm; preheating temperature: 900~1000℃; pressure: 0.5 mbar. The process parameters for preparing the composite adhesive layer using the low-pressure plasma spraying method include: current: 1600~1700 A; Ar flow rate: 110 NLPM, H2 flow rate: 6 NLPM; powder feed rate: 7.0~9.4 g / min; spray distance: 350 mm; preheating temperature: 700~800℃; pressure: 40 mbar.

2. The high-performance composite high-entropy thermal / environmental barrier coating according to claim 1, characterized in that, The matrix material is SiC. f / SiC ceramic matrix composites.

3. The high-performance composite high-entropy thermal / environmental barrier coating according to claim 1, characterized in that, The process parameters for the vacuum annealing treatment include: heating rate: 3℃ / min; holding temperature: 1250~1350℃; holding time: 2.5~3.5h; cooling rate: 2℃ / min.

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