Self-healing thermal / environmental barrier coating with high bonding strength and preparation method thereof

Abstract

The invention relates to a self-healing thermal / environmental barrier coating with high bonding strength and a preparation method thereof. The self-healing thermal / environmental barrier coating with high bonding strength sequentially comprises a micro-nano composite texture and chemical bonding transition layer, a SiC-TiC-Ti5Si3Cx multiphase ceramic bonding layer, an environmental barrier layer and a thermal barrier layer with vertical cracks from the SiC / SiC composite material matrix to the outside, vertical cracks of the thermal barrier layer are filled with a self-healing phase. Through mechanical anchoring-chemical bonding synergistic interface design, gradient bonding layer in-situ forming and three-dimensional self-healing network construction, the excellent thermal shock resistance and water oxygen corrosion resistance are achieved, wherein the room-temperature bonding strength of a matrix / bonding layer interface is larger than or equal to 50 MPa, the coating stripping area is smaller than or equal to 10% after 200 times of thermal circulation at the temperature of 1500 DEG C, and the oxidation weight increment is smaller than or equal to 1.0 mg / cm < 2 > after water oxygen corrosion at the temperature of 1500 DEG C is conducted for 100 h.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ceramic matrix composite surface protection, and particularly relates to a high-bond-strength self-healing thermal / environmental barrier coating and a preparation method thereof. BACKGROUND

[0002] With the development of aerospace engines towards high thrust-to-weight ratio and high efficiency, the service environment of hot-end components is increasingly harsh, which needs to withstand high-temperature, high-pressure gas erosion and the combined action of corrosion media such as water vapor and oxygen. Silicon carbide fiber reinforced silicon carbide matrix composite (SiC / SiC) has become a key material for hot-end components such as turbine blades and combustion chambers due to its excellent high-temperature strength and low density. However, SiC material will corrode in a high-temperature water-oxygen environment, generating volatile Si(OH)4, which leads to degradation of material performance. Therefore, a protective coating needs to be prepared on the surface of the composite material to isolate the corrosion environment and reduce the temperature of the matrix.

[0003] The environmental barrier coating (EBC) is the mainstream technology for protecting ceramic matrix composites from water-oxygen corrosion, and its typical structure includes a bonding layer, an intermediate layer and a surface layer. For example, rare earth silicates (such as Yb2SiO5 and Yb2Si2O7) as EBC surface layer can effectively block the diffusion of water and oxygen. However, the upper temperature limit of traditional EBC is usually lower than 1500°C, and when the service temperature is further increased, the EBC layer will appear sintering, phase change or softening, resulting in failure of protection. In order to improve the service temperature of EBC, researchers try to add a ceramic thermal barrier layer on the surface of EBC to form a thermal / environmental barrier (T / EBC) coating system. This system is not simply superimposed with thermal barrier coating (TBC) and environmental barrier coating, but a ceramic layer with both thermal insulation and water-oxygen corrosion resistance is constructed on the surface of EBC, so that the EBC layer works at a lower temperature, thereby expanding its temperature range.

[0004] In existing technologies, the preparation of thermal / environmental barrier coatings mainly relies on methods such as chemical vapor deposition (CVD), plasma spraying (e.g., atmospheric plasma spraying, APS), and electron beam physical vapor deposition (EB-PVD). For example, CVD can prepare dense, precisely composed coatings, but the process cycle is long, the equipment cost is high, and the mismatch in the coefficient of thermal expansion (CTE) between the coating and the substrate easily generates interfacial stress, resulting in insufficient bonding strength and easy cracking and peeling during thermal cycling. Although plasma spraying is highly efficient and suitable for large-sized workpieces, the coating has a layered structure with pores and microcracks, which become channels for corrosive media penetration. Furthermore, the mechanical interlocking between the coating and the substrate is weak, and the bonding strength is generally lower than 50 MPa. Chinese patent application CN119551988A proposes to prepare the bonding layer through an integrated impregnation-curing-pyrolysis process, avoiding secondary high-temperature treatment of the composite material. However, this method focuses on the compatibility between the bonding layer and the substrate and does not solve the problems of bonding strength and damage healing of the entire coating system.

[0005] Furthermore, traditional coatings lack self-healing capabilities. During service, coatings are prone to cracking due to external impacts, thermal shock, or corrosion. Once damaged, oxygen and water vapor penetrate along the cracks, leading to rapid oxidation and failure of the substrate. Chinese patent application CN118619712A proposes a repair method using polycarbosilane infiltration pyrolysis for graphite-based SiC coatings. However, this method is limited to graphite substrates, and the thickness of the healing layer is poorly controllable, making it difficult to apply to coating systems with complex surfaces in ceramic matrix composites. Chinese patent application CN116063102A develops an infrared-curable online repair coating based on perhydropolysilazane (PHPS) and polycarbosilane, simplifying the process. However, the coating has limited temperature resistance (typically below 1400°C), low bonding strength between the repair layer and the substrate, and insufficient long-term resistance to oxidation and ablation.

[0006] The core problems currently facing thermal / environmental barrier coating technology include multiple challenges such as weak interfacial bonding and lack of self-healing mechanism. There is an urgent need to develop a new coating system with high bonding strength, strong temperature resistance and self-healing function, which is of great significance to meeting the stringent requirements of next-generation aero-engines for high-temperature protective coatings. Summary of the Invention

[0007] To address one or more technical challenges of existing thermal / environmental barrier coating systems in extreme combustion gas erosion-water-oxygen coupled environments, such as weak interfacial bonding, large thermal expansion mismatch, and insufficient crack self-healing ability, this invention provides a high-bonding-strength self-healing thermal / environmental barrier coating and its preparation method. The self-healing thermal / environmental barrier coating of this invention sequentially constructs an integrated structure on the surface of a SiC / SiC composite matrix, consisting of a "micro-nano composite texture - chemically bonded transition layer - gradient adhesive layer - multilayer functional layer - three-dimensional self-healing network." This achieves a room-temperature bonding strength of ≥50 MPa at the matrix / adhesive layer interface, a coating peeling area ≤10% after 200 thermal cycles at 1500℃, and an oxidation weight gain ≤1.0 mg / cm³ after 100 hours of water-oxygen corrosion at 1500℃. 2 The overall performance significantly improves the thermal shock resistance and high-temperature water-oxygen corrosion resistance of the SiC / SiC composite matrix.

[0008] In a first aspect, the present invention provides a high-bonding-strength self-healing thermal / environmental barrier coating, wherein the high-bonding-strength self-healing thermal / environmental barrier coating comprises, from the SiC / SiC composite matrix outwards, a micro / nano composite texture and a chemically bonded transition layer, and a SiC-TiC-Ti5Si3C layer. x The composite ceramic bonding layer, the environmental barrier layer, and the thermal barrier layer with vertical cracks; the vertical cracks of the thermal barrier layer are filled with a self-healing phase.

[0009] Preferably, the micro / nano composite texture and the chemically bonded transition layer are formed by laser processing, reactive ion etching, and magnetron sputtering; the SiC-TiC-Ti5Si3C x The multiphase ceramic bonding layer is formed by integrated pyrolysis of a modified liquid polycarbosilane slurry containing liquid polycarbosilane, nano β-SiC powder and micron Ti powder; the environmental barrier layer is a rare earth silicate environmental barrier layer; the thermal barrier layer is a ceramic thermal barrier layer; and / or the self-healing phase is a SiC-B4C and / or SiBCN self-healing phase.

[0010] In a second aspect, the present invention provides a method for preparing a self-healing thermal / environmental barrier coating with high bonding strength, the method comprising the following steps: (1) A micro-nano composite texture was constructed on the surface of the SiC / SiC composite matrix and a Ti transition layer was deposited to obtain a micro-nano composite texture and chemical bonding transition layer on the surface of the SiC / SiC composite matrix. (2) The SiC / SiC composite matrix treated in step (1) was subjected to integrated pyrolysis treatment using modified liquid polycarbosilane slurry to obtain SiC-TiC-Ti5Si3C based on the micro-nano composite texture and chemical bonding transition layer. x Multiphase ceramic bonding layer; (3) In SiC-TiC-Ti5Si3C x An environmental barrier layer and a thermal barrier layer with vertical cracks are sequentially prepared on the surface of a multiphase ceramic bonding layer. (4) The precursors of SiC-B4C and / or SiBCN, which are pyrolysis products, are introduced into the vertical cracks of the thermal barrier layer and cured and pyrolyzed, so that the vertical cracks of the thermal barrier layer are filled with SiC-B4C and / or SiBCN self-healing phases, thereby obtaining the high bonding strength self-healing thermal / environmental barrier coating on the SiC / SiC composite matrix.

[0011] Preferably, in step (1): the SiC / SiC composite matrix is ​​a SiC / SiC ceramic matrix composite material with continuous silicon carbide fibers as the reinforcing phase and silicon carbide ceramics as the matrix phase; preferably, the surface of the continuous silicon carbide fibers of the SiC / SiC ceramic matrix composite material has an interface layer of pyrolytic carbon, silicon carbide and / or boron nitride; preferably, the density of the SiC / SiC ceramic matrix composite material is 2.1-2.8 g / cm³. 3 .

[0012] Preferably, in step (1): the method for constructing the micro / nano composite texture is as follows: first, a micro-groove array is fabricated on the surface of the SiC / SiC composite matrix using a femtosecond laser; then, a nanoscale rough structure is etched on the inner wall of the micro-groove using reactive ion etching, thereby constructing a micro / nano composite texture on the surface of the SiC / SiC composite matrix; preferably, the laser wavelength of the femtosecond laser is 515 nm, the laser pulse width is 100-500 fs, the average laser power is 5-30 W, the scanning speed is 100-1000 mm / s, and the number of scans is 3-10; preferably, the... The depth of the micro-trench array is 10-50 μm and the width is 5-20 μm; preferably, the reactive ion etching uses CF4 or SF4 as the reactive gas, the gas flow rate is 20-50 sccm, the power of the reactive ion etching is 100-300 W, and the time is 5-15 min; and / or a Ti transition layer is deposited by DC magnetron sputtering; preferably, the sputtering pressure of DC magnetron sputtering is 0.3-0.8 Pa, the power is 100-200 W, and the time is 20-60 min; preferably, the thickness of the Ti transition layer is 50-200 nm.

[0013] Preferably, in step (2): the modified liquid polycarbosilane slurry comprises liquid polycarbosilane, nano-β-SiC powder, and micron-sized Ti powder; preferably, the viscosity of the liquid polycarbosilane is 20-100 mPa·s, and the particle size D of the nano-β-SiC powder is... 50 The particle size D of the micron-sized Ti powder is 20-100 nm. 50The thickness is 1-3 μm; preferably, the modified liquid polycarbosilane slurry contains 3-7 vol% nano-β-SiC powder by volume, and / or the modified liquid polycarbosilane slurry contains 2-5 vol% micron-sized Ti powder by volume; the integrated pyrolysis treatment is as follows: the modified liquid polycarbosilane slurry is introduced into the micro-nano composite texture and chemical bonding transition layer on the surface of the SiC / SiC composite matrix by brushing, dip coating or vacuum impregnation, and then cured and pyrolyzed; preferably, the integrated pyrolysis treatment is repeated 1-3 times; preferably, the curing is performed at 100-200°C for 10-30 min in a nitrogen and / or argon atmosphere, and the pyrolysis is performed at 1100-1400°C for 1-2 h in an argon atmosphere at a heating rate of 1-5°C / min; and / or the SiC-TiC-Ti5Si3C x The thickness of the multiphase ceramic bonding layer is 50-200μm.

[0014] Preferably, in step (3): the environmental barrier layer is prepared by thermal spraying, preferably, the thermal spraying is one or more of atmospheric plasma spraying, supersonic flame spraying, suspension plasma spraying, and plasma physical vapor deposition; the environmental barrier layer is a rare earth silicate environmental barrier layer, preferably, the rare earth silicate environmental barrier layer is a Yb2SiO5 and / or Yb2Si2O7 rare earth silicate environmental barrier layer; the thickness of the environmental barrier layer is 100-200 μm; one or more of atmospheric plasma spraying, electron beam physical vapor deposition, and plasma physical vapor deposition are used. A thermal barrier layer with vertical cracks is prepared on the surface of the environmental barrier layer; the thermal barrier layer is a ceramic thermal barrier layer, preferably, the ceramic thermal barrier layer is made of one or more of zirconium oxide, hafnium oxide, rare earth zirconate, and rare earth hafnium salt, and / or the ceramic thermal barrier layer is made of one or more of rare earth oxide modified zirconium oxide, hafnium oxide, rare earth zirconate, and rare earth hafnium salt, preferably, the rare earth oxide is Y2O3 and / or Yb2O3; the thickness of the thermal barrier layer is 100-400 μm; and / or the density of the vertical cracks is 0.005~2 cracks / μm.

[0015] Preferably, in step (4): the precursor of pyrolysis product SiC-B4C and / or SiBCN is introduced into the vertical crack of the thermal barrier layer by vacuum impregnation; the vacuum impregnation is carried out at a vacuum degree of 10-100kPa for 0.5-3h; the curing is carried out at 100-300°C for 1-3h; the pyrolysis is carried out in an argon atmosphere at a heating rate of 1-3°C / min to 1100-1400°C for 1-2h; and / or the precursor of pyrolysis product SiC-B4C and / or SiBCN is boron-modified polycarbosilane, polycarbosilane containing nano B4C powder and / or polyborosilicate.

[0016] Preferably, the high-bonding-strength self-healing thermal / environmental barrier coating comprises SiC-TiC-Ti5Si3C x The room temperature bond strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​≥50 MPa; and / or the high-bonding-strength self-healing thermal / environmental barrier coating exhibits a coating peeling area ≤10% after 200 thermal cycles at 1500°C, and an oxidation weight gain ≤1.0 mg / cm³ after 100 hours of water-oxygen corrosion at 1500°C. 2 .

[0017] In a third aspect, the present invention provides a self-healing thermal / environmental barrier coating with high bonding strength prepared by the preparation method described in the second aspect of the present invention.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects: (1) Traditional thermal / environmental barrier coatings rely primarily on mechanical interlocking for physical bonding with the SiC / SiC composite matrix (e.g., CN119551988A), with bonding strength generally below 40 MPa. Under thermal shock conditions, the mismatch in thermal expansion coefficients easily leads to interfacial stress concentration, causing delamination failure between the coating and the matrix. This invention pre-treats the matrix surface, employs laser processing and reactive ion etching to form a micro-groove array and a nanoscale rough structure, significantly increasing the specific surface area and interlocking sites. Furthermore, it uses magnetron sputtering of titanium films, combined with modified LPCS slurry, to react with the matrix and SiC adhesive layer under high-temperature pyrolysis to generate SiC-TiC-Ti5Si3C with high bonding strength. x The composite ceramic bonding layer of this invention adopts a three-in-one design of "laser microgrooving + nano-rough structure + Ti chemical bonding transition layer" to form a mechanical-chemical synergistic bonding interface, and is combined with SiC-TiC-Ti5Si3C obtained by integrated pyrolysis treatment of modified LPCS slurry. x The multiphase ceramic adhesive layer enhances the interfacial bonding strength of the substrate / adhesive layer to over 50 MPa, effectively suppressing interfacial delamination during thermal cycling and significantly improving the thermal cycling life of the coating.

[0019] (2) Conventional LPCS undergoes a volume shrinkage of over 45% during pyrolysis, and existing technologies using conventional LPCS slurry to prepare SiC binders are prone to cracking and debonding. This invention introduces nano-β-SiC powder nucleating agent and micron-sized Ti active filler into the LPCS slurry. The approximately 40% volume expansion of TiC during formation partially offsets the shrinkage of LPCS and forms pinning, reducing cracks at the substrate / binder interface caused by LPCS volume shrinkage, reducing the porosity of the coating, achieving a dense and tough binder, and improving the coating's resistance to water and oxygen corrosion.

[0020] (3) Existing thermal / environmental barrier coatings, although the introduced vertical cracks can alleviate stress concentration and help release stress, have insufficient self-healing properties. This invention introduces precursors with self-healing properties from vacuum impregnation pyrolysis products into the vertical cracks of the thermal barrier layer. After pyrolysis, the SiC-B4C and / or SiBCN ceramic phases will fully fill the crack channels, forming a three-dimensional self-healing network distributed in the thermal barrier layer. When microcracks are generated in the coating at high temperature, the borate glass formed by the SiC-B4C and / or SiBCN ceramic phases at high temperature can fill the defects in situ, achieving active healing. At the same time, compared with traditional self-healing oxides such as SiO2 or B2O3 alone, the borate glass has better resistance to water and oxygen corrosion, avoiding the reduction of self-healing performance caused by water and oxygen corrosion, and further improving the service performance of the coating. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments are briefly described below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a scanning electron microscope image of the thermal barrier layer with vertical cracks prepared in Example 1 of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] In a first aspect, the present invention provides a high-bonding-strength self-healing thermal / environmental barrier coating, wherein the high-bonding-strength self-healing thermal / environmental barrier coating comprises, from the SiC / SiC composite matrix outwards, a micro / nano composite texture and a chemically bonded transition layer, and a SiC-TiC-Ti5Si3C layer. x The invention comprises a multiphase ceramic bonding layer, an environmental barrier layer, and a thermal barrier layer with vertical cracks; the vertical cracks in the thermal barrier layer are filled with a self-healing phase, which forms a three-dimensional self-healing network. In this invention, "vertical crack" refers to a crack and / or gap extending along the thickness direction of the thermal barrier layer and whose extension direction is substantially perpendicular to the substrate surface; the gap refers to the microscopic gap formed by the separation between columnar crystal structures in the thermal barrier layer prepared by electron beam physical vapor deposition (EB-PVD) or plasma physical vapor deposition (PS-PVD).

[0025] This invention utilizes a synergistic interface design of "mechanical anchoring-chemical bonding," in-situ molding of a gradient adhesive layer, and construction of a three-dimensional self-healing network. Specifically, the self-healing thermal / environmental barrier coating sequentially constructs an integrated structure on the surface of a SiC / SiC composite matrix, consisting of "micro-nano composite texture - chemically bonded transition layer - gradient adhesive layer - multilayer functional layer - three-dimensional self-healing network." This achieves a high-bonding-strength self-healing thermal / environmental barrier coating with a room temperature bond strength ≥50 MPa at the matrix / adhesive layer interface, a coating peeling area ≤10% after 200 cycles at 1500°C, and an oxidation weight gain ≤1.0 mg / cm³ after 100 hours of water-oxygen corrosion at 1500°C. 2 Its excellent thermal shock resistance and water-oxygen corrosion resistance significantly improve the thermal shock resistance and high-temperature water-oxygen corrosion resistance of SiC / SiC composite matrix.

[0026] According to some preferred embodiments, the micro / nano composite texture and the chemically bonded transition layer are formed by laser processing, reactive ion etching, and magnetron sputtering; preferably, the micro / nano composite texture is first fabricated using a femtosecond laser to create a micro-groove array, and then a nanoscale rough structure is etched on the inner wall of the micro-grooves using reactive ion etching. The chemically bonded transition layer is a Ti transition layer, which is deposited on the surface of the micro / nano composite texture by magnetron sputtering; the SiC-TiC-Ti5Si3C x The multiphase ceramic bonding layer is formed by integrated pyrolysis of a modified liquid polycarbosilane slurry containing liquid polycarbosilane, nano-β-SiC powder and micron-sized Ti powder; the environmental barrier layer is a rare earth silicate environmental barrier layer; the thermal barrier layer is a ceramic thermal barrier layer; and / or the self-healing phase is a SiC-B4C self-healing phase and / or a SiBCN self-healing phase.

[0027] In a second aspect, the present invention provides a method for preparing a self-healing thermal / environmental barrier coating with high bonding strength, the method comprising the following steps: (1) After constructing a micro-nano composite texture on the surface of the SiC / SiC composite matrix (SiC fiber reinforced SiC composite matrix), a Ti (titanium) transition layer (also referred to as titanium film) is deposited to obtain a micro-nano composite texture and a chemical bonding transition layer on the surface of the SiC / SiC composite matrix; In this invention, laser processing and reactive ion etching are used to construct the micro-nano composite texture to improve the specific surface area and locking sites; a titanium film is deposited by magnetron sputtering as a chemical bonding transition layer to form a mechanical-chemical synergistic locking interface; (2) The SiC / SiC composite matrix treated in step (1) was subjected to integrated pyrolysis treatment using modified liquid polycarbosilane slurry (abbreviated as modified LPCS slurry) to obtain SiC-TiC-Ti5Si3C based on the micro-nano composite texture and chemical bonding transition layer. x Multiphase ceramic bonding layer; In step (2) of the present invention, modified liquid polycarbosilane slurry is in-situ pyrolyzed on the surface of the micro-nano composite texture and chemical bonding transition layer of the SiC / SiC composite matrix treated in step (1) to generate SiC-TiC-Ti5Si3C. x Multiphase ceramic bonding layers can generate a pinning effect, thereby improving the interfacial bonding strength; (3) In SiC-TiC-Ti5Si3C x An environmental barrier layer (also referred to as the environmental barrier intermediate layer) and a thermal barrier layer with vertical cracks (also referred to as the thermal barrier surface layer) are sequentially prepared on the surface of the multiphase ceramic bonding layer. (4) The precursor (ceramic precursor) of SiC-B4C and / or SiBCN, which are pyrolysis products, is introduced into the vertical crack of the thermal barrier layer and cured and pyrolyzed, so that the vertical crack of the thermal barrier layer is filled with the self-healing phase of SiC-B4C and / or SiBCN, thereby obtaining the high bonding strength self-healing thermal / environmental barrier coating on the SiC / SiC composite matrix; In this invention, the SiC-B4C and / or SiBCN three-dimensional continuous self-healing phase distributed in the thermal barrier layer is formed.

[0028] Traditional thermal / environmental barrier coatings rely primarily on mechanical bonding with the SiC / SiC composite matrix (e.g., CN119551988A), resulting in bond strengths generally below 40 MPa. Under thermal shock conditions, the mismatch in thermal expansion coefficients easily leads to interfacial stress concentration, causing delamination failure between the coating and the matrix. This invention addresses this by pretreating the matrix surface, employing laser processing and reactive ion etching to create a micro-groove array and a nanoscale rough structure, significantly increasing the specific surface area and bonding sites. Furthermore, magnetron sputtering of a titanium film, combined with a modified LPCS slurry, reacts with the matrix and SiC adhesive layer under high-temperature pyrolysis to generate a high-bonding SiC-TiC-Ti5Si3C composite. xThe composite ceramic bonding layer of this invention adopts a three-in-one design of "laser microgrooving + nano-rough structure + Ti chemical bonding transition layer" to form a mechanical-chemical synergistic bonding interface, and is combined with SiC-TiC-Ti5Si3C obtained by integrated pyrolysis treatment of modified LPCS slurry. x The multiphase ceramic adhesive layer enhances the interfacial bonding strength of the substrate / adhesive layer to over 50 MPa, effectively suppressing interfacial delamination during thermal cycling and significantly improving the thermal cycling life of the coating.

[0029] Conventional LPCS undergoes volume shrinkage exceeding 45% during pyrolysis, leading to cracking and debonding when using conventional LPCS slurries to prepare SiC binders. This invention introduces nano-β-SiC powder nucleating agents and micron-sized Ti active fillers into the LPCS slurry. The approximately 40% volume expansion of TiC during formation partially offsets the LPCS shrinkage and forms pinning structures, reducing cracks at the substrate / binder interface caused by LPCS volume shrinkage. This reduces coating porosity, achieving a dense and tough binder layer and improving its resistance to water and oxygen corrosion. While existing thermal / environmental barrier coatings can alleviate stress concentration and promote stress release through introduced vertical cracks, their self-healing properties are insufficient. This invention introduces a precursor with self-healing properties, which is a product of vacuum impregnation pyrolysis, into the vertical cracks of the thermal barrier layer. After pyrolysis, the SiC-B4C and / or SiBCN ceramic phases fully fill the vertical crack channels, forming a three-dimensional continuous self-healing network. When microcracks are generated in the coating at high temperatures, the borate glass formed by the SiC-B4C and / or SiBCN ceramic phases at high temperatures can fill the defects in situ, achieving active healing. At the same time, compared with traditional self-healing oxides such as SiO2 or B2O3 alone, the borate glass has better resistance to water and oxygen corrosion, avoiding the reduction of self-healing performance caused by water and oxygen corrosion, and further improving the service performance of the coating.

[0030] According to some specific embodiments, the preparation of the high-bonding-strength self-healing thermal / environmental barrier coating includes: (1) Pretreatment of the substrate interface: First, the SiC / SiC composite matrix is ​​ultrasonically cleaned to thoroughly remove surface oil. Then, a femtosecond laser is used to process a micro-groove array on the cleaned SiC / SiC composite matrix surface, and a nanoscale rough structure is introduced on the inner wall of the micro-groove using reactive ion etching to form a micro-nano composite texture. Finally, a pure Ti film (Ti transition layer) is deposited on the textured surface by DC magnetron sputtering. In this invention, for example, acetone and / or ethanol are used to ultrasonically clean the SiC / SiC composite matrix for 20-40 min (e.g., 20, 30 or 40 min), and vacuum dry at 100-150°C (e.g., 100°C, 125°C or 150°C) for 1-2 h (e.g., 1, 1.5 or 2 h) to remove surface oil. (2) Preparation of modified liquid polycarbosilane (LPCS) slurry and integrated molding of the adhesive layer: First, nano-β-SiC powder as a nucleating agent and micron-sized Ti powder as an active filler are added to liquid polycarbosilane. After mixing, a uniform and stable modified LPCS slurry is obtained. Then, the modified LPCS slurry is introduced into the micro-nano composite texture and chemical bonding transition layer on the surface of the SiC / SiC composite matrix by brushing, dip coating or vacuum impregnation (vacuum-assisted impregnation). After curing and pyrolysis, a dense SiC-TiC-Ti5Si3C is obtained. x Multiphase ceramic bonding layer, SiC-TiC-Ti5Si3C x The multiphase ceramic binder layer comprises SiC transformed from LPCS pyrolysis, microcrystallization induced by nano-β-SiC powder, and TiC and Ti5Si3C generated by in-situ reaction of Ti powder with free carbon in the substrate Ti film and slurry. x The phase serves as the pinning location; (3) Preparation of thermal / environmental barrier multilayer coating: First, a thermal spraying method was used to apply the coating to the prepared SiC-TiC-Ti5Si3C layer. x A rare-earth silicate environmental barrier intermediate layer was prepared on the surface of the multiphase ceramic bonding layer; subsequently, a ceramic thermal barrier surface layer with vertical cracks was prepared on the surface of the environmental barrier layer. (4) Construction of three-dimensional self-healing network: The ceramic precursor with self-healing properties of the pyrolysis products is introduced into the vertical crack of the ceramic thermal barrier layer by vacuum impregnation method (vacuum-assisted impregnation method). Then, the ceramic precursor is pyrolyzed in situ to transform into SiC-B4C or SiBCN ceramic self-healing phase, which fills and heals the crack, forming a three-dimensional continuous self-healing network distributed in the ceramic thermal barrier layer.

[0031] According to some preferred embodiments, in step (1): the SiC / SiC composite matrix is ​​a SiC / SiC ceramic matrix composite material with continuous silicon carbide fibers as the reinforcing phase and silicon carbide ceramics as the matrix phase; preferably, the surface of the continuous silicon carbide fibers of the SiC / SiC ceramic matrix composite material has a pyrolytic carbon, silicon carbide and / or boron nitride interface layer, that is, the SiC / SiC ceramic matrix composite material is deposited with a pyrolytic carbon interface layer, a silicon carbide interface layer and / or a boron nitride interface layer (BN interface layer); the present invention does not specifically limit the SiC / SiC ceramic matrix composite material, and those skilled in the art can conventionally select it; preferably, the density of the SiC / SiC ceramic matrix composite material is 2.1-2.8 g / cm³. 3 (e.g., 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7 or 2.8 g / cm³) 3 ).

[0032] According to some preferred embodiments, in step (1): the method for constructing the micro-nano composite texture is as follows: firstly, a micro-groove array is processed on the surface of the SiC / SiC composite matrix using a femtosecond laser. Specifically, a micro-groove array is processed on the cleaned SiC / SiC composite matrix using a femtosecond laser, and then a nanoscale rough structure is etched on the inner wall of the micro-groove using reactive ion etching (RIE), thereby constructing a micro-nano composite texture on the surface of the SiC / SiC composite matrix; in this invention, the micro-groove array is composed of multiple micro-level grooves, i.e., micro-grooves arranged in an orderly manner; preferred Yes, the femtosecond laser has a wavelength of 515 nm, a pulse width of 100-500 fs (e.g., 100, 300, or 500 fs), an average laser power of 5-30 W (e.g., 5, 10, 15, 20, 25, or 30 W), a scanning speed of 100-1000 mm / s (e.g., 100, 300, 500, 700, or 1000 mm / s), and a number of scans (repeated scans) of 3-10 times (e.g., 3, 5, 7, or 10 times); preferably, the depth of the micro-grooves in the micro-groove array is 10-50 μm (e.g., 10, 30, or 50 μm). The width of the micrometer trenches is 5-20 μm (e.g., 5, 10, 15, or 20 μm), and the spacing between two adjacent micrometer trenches (adjacent trench spacing) is 5-20 μm (e.g., 5, 10, 15, or 20 μm). Preferably, the reactive ion etching uses carbon tetrafluoride (CF4) or sulfur tetrafluoride (SF4) as the reactive gas, with a gas flow rate of 20-50 sccm (e.g., 20, 35, or 50 sccm). The power of the reactive ion etching is 100-300 W (e.g., 100, 200, or 300 W), and the time is 5-15 min (e.g., 5, 10, or 15 min). The process involves inducing a nanoscale rough structure on the inner wall of the trench to obtain a micro-nano composite texture; and / or depositing a Ti transition layer by DC magnetron sputtering, i.e., depositing a pure Ti film on the surface of the micro-nano composite texture using DC magnetron sputtering; preferably, the sputtering pressure of the DC magnetron sputtering is 0.3-0.8 Pa (e.g., 0.3, 0.5 or 0.8 Pa), the power is 100-200 W (e.g., 100, 150 or 200 W), and the time is 20-60 min (e.g., 20, 40 or 60 min); preferably, the thickness of the Ti transition layer is 50-200 nm (e.g., 50, 150 or 200 nm).

[0033] This invention constructs a micron-level trench array and a nanoscale rough structure on the substrate surface through laser processing and reactive ion etching, significantly increasing the specific surface area and mechanical locking sites. Subsequently, a titanium film with a thickness of 50-200 nm is deposited by magnetron sputtering. This titanium film can also undergo in-situ reaction with the active substances generated during the subsequent pyrolysis of modified liquid polycarbosilane slurry, participating in the formation of SiC-TiC-Ti5Si3C.x A multiphase ceramic bonding layer is used to further enhance the interfacial chemical bonding strength. In this invention, the titanium film thickness is preferably controlled within the range of 50-200 nm. This ensures that the film layer can fully cover the rough substrate, achieving a uniform, continuous, and reactive transition layer, while avoiding excessive internal stress, embrittlement, or incomplete reaction caused by excessive thickness. This invention has found that if the titanium film thickness is too low, the film layer coverage will be insufficient and the reactive titanium content will be low, leading to discontinuity of the multiphase ceramic bonding layer and insufficient chemical bonding points, thereby reducing the interfacial bonding strength. If the thickness is too high, it may lead to excessive titanium during the pyrolysis process, an imbalance in the phase formation ratio, stress cracking or peeling of the film layer, which will weaken the entire SiC-TiC-Ti5Si3C. x The bonding strength between the interface of the multiphase adhesive layer and the substrate and its long-term service reliability.

[0034] According to some preferred embodiments, in step (2): the modified liquid polycarbosilane slurry comprises liquid polycarbosilane, nano-β-SiC powder, and micron-sized Ti powder; preferably, the viscosity of the liquid polycarbosilane is 20-100 mPa·s (e.g., 20, 60, or 100 mPa·s), and the particle size D of the nano-β-SiC powder is... 50 The particle size D of the micron-sized Ti powder is 20-100 nm (e.g., 20, 60, or 100 nm). 50 The thickness is 1-3 μm (e.g., 1, 2, or 3 μm); preferably, the modified liquid polycarbosilane slurry contains 3-7 vol% (e.g., 3%, 5%, or 7%) of nano-β-SiC powder by volume, and / or the modified liquid polycarbosilane slurry contains 2-5 vol% (e.g., 2%, 3%, 4%, or 5%) of micron-sized Ti powder by volume; in this invention, the modified liquid polycarbosilane slurry is prepared, for example, with liquid polycarbosilane (with a viscosity of 20-100 mPa·s at 25°C)... Using LPCS as the matrix, 3-7 vol% of nano β-SiC powder (median particle size D50 = 20-100 nm) and 2-5 vol% of micron Ti powder (median particle size D50 = 1-3 μm) are added as nucleating agents to obtain a mixture. The mixture is then placed in a planetary ball mill or a high-speed shear disperser and ball-milled or sheared at a speed of 200-400 rpm for 4-12 h (e.g., 4, 8 or 12 h) to obtain a uniform and stable modified liquid polycarbosilane slurry (modified LPCS slurry).

[0035] This invention utilizes a modified liquid polycarbosilane slurry containing liquid polycarbosilane, nano-β-SiC powder as a nucleating agent, and micron-sized Ti powder as an active filler, which is then subjected to integrated pyrolysis to form SiC-TiC-Ti5Si3C. x Multiphase ceramic binder and prior art disclosed by using SiC f / SiC f The matrix is ​​embedded with powder and subjected to high-temperature heat treatment to generate TiC-Ti3SiC2-Ti5Si3C x Compared to the Ti-Si-C composite coating with a specific structure (see CN116836002A), the modified liquid polycarbosilane slurry of this invention, which uses liquid polycarbosilane as a matrix and adds nano-β-SiC as a nucleating agent and micron-sized Ti powder as an active filler, forms SiC-TiC-Ti5Si3C through integrated pyrolysis after brushing, dip coating, or vacuum impregnation. x Multiphase ceramic binders offer multiple advantages in enhancing the bond strength between the substrate and the binder: Firstly, the liquid precursor can fully penetrate and fill the micro / nano composite texture of the substrate surface through brushing, dip coating, or vacuum-assisted impregnation, forming a continuous interface highly conforming to the surface morphology. This significantly increases the mechanical interlocking area and reduces macro / micro porosity, a feature difficult to achieve with powder embedding. Secondly, the modified liquid polycarbosilane slurry undergoes in-situ reaction with the chemically bonded transition layer (Ti film) and micron-sized Ti active filler during pyrolysis, forming a refined and uniformly distributed TiC phase under the induction of nano-β-SiC, while simultaneously generating Ti5Si3C. x The iso-reactive phase yields a dense, multi-phase transitional bonding layer that combines microscale chemical bonding with macroscale mechanical interlocking, effectively mitigating interfacial thermodynamic and thermomechanical mismatches. Furthermore, integrated pyrolysis allows for precise adjustment of phase composition, grain size, and layer density by controlling the slurry formulation, nucleating agent content, micron-sized Ti active filler, and pyrolysis cycle count, thereby achieving higher interfacial bonding strength and lower defect density while maintaining a thin layer. In contrast, structures formed by powder embedding followed by high-temperature heat treatment are prone to introducing unreacted residues, interfacial pores, or discontinuous layered interfaces, affecting bonding uniformity and strength. For example, the Ti-Si-C composite coating prepared in CN116836002A has a bonding strength of only 14.4~42.7 MPa, while the SiC-TiC-Ti5Si3C obtained in this invention... x Multiphase ceramic adhesive layers are more conducive to obtaining adhesive layers with high bonding strength and improving interface reliability. This invention can improve the bonding strength of the matrix / adhesive layer interface to more than 50 MPa.

[0036] In this invention, nano-β-SiC is selected as the nucleating agent and micron-sized Ti powder is selected as the active filler. The β phase as the nucleating agent can promote the densification of SiC and avoid the volume change caused by the phase transformation of the α phase at high temperature. At the same time, it is preferred that the volume fractions of the two are controlled at 3-7 vol% and 2-5 vol%, respectively, so as to achieve the best balance between the phase composition, microstructure and interfacial properties of the binder layer, thereby obtaining a dense, uniform SiC-TiC-Ti5Si3C with high bonding strength. xMultiphase ceramics; This invention discovers that when the content of nano-β-SiC is between 3-7 vol%, it can provide sufficient but not excessive nucleation sites during the pyrolysis of polycarbosilane, resulting in dense β-SiC nucleation and grain refinement. This is beneficial for suppressing microcracks caused by pyrolysis shrinkage, while ensuring the continuity and density of the bonding layer. If the β-SiC content is too low, sufficient nucleation sites cannot be formed, leading to increased porosity and decreased bonding strength. If the β-SiC content is too high, its high specific surface area will significantly increase the viscosity of the system and affect the ability of the slurry to penetrate the micro-nano composite texture, and may also lead to… Excessive adsorption of free carbon or silicon during pyrolysis causes the phase composition to deviate from the design and induces agglomeration, forming brittle SiC-rich regions. This invention reveals that, compared to nano-Ti powder, micron-sized Ti powder exhibits less vigorous reaction, significantly reducing local overheating, porosity, or the formation of abnormally coarse reaction phases. This results in a more continuous, uniform, and brittle titanium-rich large-scale multiphase interface. Furthermore, controlling the micron-sized Ti powder content at 2-5 vol% maintains moderate reactivity within the pyrolysis temperature range, allowing for a controllable reaction with the pyrolysis products to generate uniform TiC and Ti5Si3C. x The phase ensures that the adhesive layer achieves optimal matching in terms of chemical bonding and thermal expansion gradient; if the content of micron-sized Ti powder is too low, the active metal will be insufficient, leading to TiC / Ti5Si3C x Insufficient phase formation reduces the bonding performance of the adhesive layer; if the content of micron-sized Ti powder is too high, coarse TiC particles or local titanium-rich areas are easily formed, resulting in uneven thermal expansion coefficients, increased local micropore formation during the pyrolysis process, and high residual stress, which in turn reduces interface stability and bonding strength.

[0037] According to some preferred embodiments, the integrated pyrolysis treatment involves: introducing the modified liquid polycarbosilane slurry into the micro / nano composite texture and chemical bonding transition layer on the surface of the SiC / SiC composite matrix by brushing, dip coating, or vacuum impregnation, followed by curing and pyrolysis; this invention uses a brushing method to introduce the modified liquid polycarbosilane slurry, and the thickness of the brushing is not specifically limited. Those skilled in the art can determine the thickness based on the preset SiC-TiC-Ti5Si3C... xThe thickness of the multiphase ceramic binder layer can be conventionally selected; preferably, the integrated pyrolysis treatment is repeated 1 to 3 times (e.g., 1, 2, or 3 times); preferably, the curing is performed at 100-200°C (e.g., 100°C, 150°C, or 200°C) for 10-30 minutes (e.g., 10, 20, or 30 minutes) in a nitrogen and / or argon atmosphere, and the pyrolysis is performed in an argon atmosphere (e.g., high-purity A with a purity ≥99.999%). Under a refractory atmosphere, the temperature is increased to 1100-1400°C (e.g., 1100°C, 1200°C, or 1400°C) at a heating rate of 1-5°C / min (e.g., 1, 2.5, or 5°C / min) for 1-2 h (e.g., 1, 1.5, or 2 h). During this process, LPCS decomposes into SiC, nano-β-SiC induces microcrystallization, and Ti reacts in situ with the substrate Ti film and free carbon to generate TiC and Ti5Si3C. x Finally, dense SiC-TiC-Ti5Si3C with a thickness of 50-200 μm was obtained. x Multiphase ceramic bonding layer; and / or the SiC-TiC-Ti5Si3C x The thickness of the multiphase ceramic adhesive layer is 50-200 μm (e.g., 50, 100, 150 or 200 μm).

[0038] According to some preferred embodiments, in step (3): the environmental barrier layer is prepared by thermal spraying (including but not limited to atmospheric plasma spraying, supersonic plasma spraying, suspension plasma spraying, and plasma physical vapor deposition). xThe environmental barrier layer (EBC) is deposited on the surface of the multiphase ceramic binder. Preferably, the thermal spraying is one or more of atmospheric plasma spraying (APS), high-velocity oxygen fuel spraying (HVOF), suspension plasma spraying (SPS), and plasma physical vapor deposition (PS-PVD). In this invention, plasma physical vapor deposition (PS-PVD) refers to plasma spraying-physical vapor deposition (PS-PVD). In this invention, the preparation of the environmental barrier layer is a conventional technique in the art. This invention does not specify the specific process conditions for preparing the environmental barrier layer; the environmental barrier layer is a rare earth silicate environmental barrier layer, preferably a Yb₂SiO₅ (ytterbium monosilicate) and / or Yb₂Si₂O₇ (ytterbium disilicate) rare earth silicate environmental barrier layer; the thickness of the environmental barrier layer is 100-200 μm (e.g., 100, 150, or 200 μm); atmospheric plasma spraying (APS), electron beam physical vapor deposition (EB-PVD), and plasma coating are employed. A thermal barrier layer with vertical cracks is prepared on the surface of the environmental barrier layer using one or more methods of physical vapor deposition (PS-PVD); the thermal barrier layer is a ceramic thermal barrier layer, preferably, the material used for the ceramic thermal barrier layer is one or more of zirconium oxide (ZrO2), hafnium oxide (HfO2), rare earth zirconates, and rare earth hafnium salts, and / or the material used for the ceramic thermal barrier layer is rare earth oxide (such as Y2O3 and / or Yb2O3) modified zirconium oxide, hafnium oxide, rare earth zirconates, and rare earth hafnium salts. One or more of the materials can be modified with rare earth oxides, preferably Y₂O₃ (yttrium oxide) and / or Yb₂O₃ (ytterbium oxide); the thickness of the thermal barrier layer is 100-400 μm (e.g., 100, 200, 300 or 400 μm); and / or the density of the vertical cracks is 0.005~2 cracks / μm (e.g., 0.005, 0.008, 0.01, 0.05, 1 or 2 cracks / μm). In this invention, the preparation of the thermal barrier layer with vertical cracks is a conventional technique in the art. This invention does not specifically limit the preparation process conditions. For example, using APS, EB-PVD and PS-PVD, the thermal barrier coating with vertical cracks can be obtained by controlling parameters such as spraying power, deposition rate, deposition temperature and / or cooling rate.

[0039] According to some preferred embodiments, in step (4): a precursor of SiC-B4C and / or SiBCN (including but not limited to boron-modified polycarbosilane, polyborosilicate, etc.) that is a pyrolysis product is introduced into the vertical crack of the thermal barrier layer (TBC) by vacuum impregnation; the vacuum impregnation is performed at a vacuum degree of 10-100 kPa (e.g., 10, 30, 50, 70 or 100 kPa) for 0.5-3 h (e.g., 0.5, 1.5 or 3 h); wherein, the vacuum degree is the difference between atmospheric pressure and absolute pressure; the curing is performed at 100-300°C (e.g., 100°C, 200°C or 300°C) for 1-3 h (e.g., 1, 2 or 3 h). In some specific embodiments, a ceramic precursor whose pyrolysis products are SiC-B4C and / or SiBCN is introduced into the vertical crack of the thermal barrier layer using vacuum-assisted impregnation. Specifically, the SiC / SiC composite matrix with the aforementioned environmental barrier layer is impregnated in the precursor, and the vacuum degree is adjusted to 10-100 kPa for 0.5-3 h of vacuum impregnation, followed by curing at 100-300 °C for 1-3 h to ensure that the precursor fully fills the crack channel. The pyrolysis is carried out in an argon atmosphere (e.g., flowing or static high-purity Ar atmosphere, purity ≥99.999%) at a heating rate of 1-3 °C / min (e.g., 1 °C / min, 2 °C / min, or 3 °C / min). The precursor is pyrolyzed at 1100-1400°C (e.g., 1100°C, 1200°C, 1300°C, or 1400°C) for 1-2 hours (e.g., 1, 1.5, or 2 hours). During this process, the precursor is pyrolyzed in situ and transformed into SiC-B4C and / or SiBCN ceramic phases, filling and healing cracks to form a three-dimensional self-healing network, resulting in a three-dimensional continuous self-healing network distributed within the thermal barrier layer; and / or the precursor of the pyrolysis product being SiC-B4C and / or SiBCN is boron-modified polycarbosilane, polycarbosilane containing nano-B4C powder, and / or polyborosilicate; this invention does not specifically limit the precursor of the pyrolysis product being SiC-B4C and / or SiBCN. Those skilled in the art can conventionally choose, in this invention, that the boron-modified polycarbosilane is a liquid boron-modified polycarbosilane, for example, a commercially available liquid boron-containing polycarbosilane or a liquid boron-containing polycarbosilane prepared by existing methods, with a viscosity range of, for example, 20-100 mPa·s; the polycarbosilane containing nano-B4C powder is a liquid polycarbosilane modified with nano-B4C powder, and its preparation method is, for example, by ball milling nano-B4C powder into liquid polycarbosilane for 4 hours; the volume percentage of nano-B4C powder (particle size D50 of 20-100 nm) in the polycarbosilane containing nano-B4C powder is, for example, 4-8%; the polyborosilicate is, for example, a liquid polyborosilicate.

[0040] According to some preferred embodiments, the high-bonding-strength self-healing thermal / environmental barrier coating comprises SiC-TiC-Ti5Si3C x The room temperature bond strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​≥50 MPa; and / or the high-bonding-strength self-healing thermal / environmental barrier coating exhibits a coating peeling area ≤10% after 200 thermal cycles at 1500°C, and an oxidation weight gain ≤1.0 mg / cm³ after 100 hours of water-oxygen corrosion at 1500°C. 2 .

[0041] In a third aspect, the present invention provides a self-healing thermal / environmental barrier coating with high bonding strength prepared by the preparation method described in the second aspect of the present invention.

[0042] The present invention will be further described below by way of examples, but the scope of protection of the present invention is not limited to these embodiments. The present invention may have many other embodiments, and those skilled in the art can make various corresponding changes and modifications based on the present invention without departing from its spirit and essence; however, all such corresponding changes and modifications should fall within the scope of protection of the appended claims.

[0043] Example 1 ① Substrate Interface Pretreatment: The substrate selected was a SiC / SiC ceramic matrix composite material with a deposited BN interface layer. First, the substrate was ultrasonically cleaned with acetone for 30 min, and then dried in a vacuum drying oven at 120°C for 1.5 h to remove surface contaminants. Next, a femtosecond laser processing system was used to construct a micro-groove array on the substrate surface. The laser wavelength was 515 nm, the laser pulse width was 300 fs, the average laser power was 15 W, the scanning speed was 500 mm / s, and the scan was repeated 5 times. The micro-groove depth was 30 μm, the width was 10 μm, and the spacing between adjacent grooves was 10 μm. Subsequently, reactive ion etching was performed using CF4 as the reactive gas, the gas flow rate was 35 sccm, the reactive ion etching power was 200 W, and the time was 10 min to form a micro-nano composite texture. Finally, a pure Ti film was deposited on the surface of the micro-nano composite texture as a chemical bonding transition layer by DC magnetron sputtering. The sputtering pressure was 0.5 Pa, the power was 150 W, the time was 40 min, and the Ti film thickness was 100 nm, thus obtaining the micro-nano composite texture and chemical bonding transition layer on the substrate surface.

[0044] ② Modified LPCS slurry preparation and integrated molding of adhesive layer: Prepare modified LPCS slurry using liquid polycarbosilane with a viscosity of 50 mPa·s at 25°C as the matrix, add 5 vol% nano β-SiC powder (D50=50nm) as nucleating agent and 3 vol% micron Ti powder (D50=2μm) as active filler, ball mill for 8 hours to obtain uniform modified LPCS slurry, that is, the volume percentage of nano β-SiC powder in the modified LPCS slurry is 5 vol%, and the volume percentage of micron Ti powder is 3 vol%. Modified LPCS slurry was introduced into a micro / nano composite texture and chemically bonded transition layer on the substrate surface using a brush coating method. Then, curing and pyrolysis were repeated twice. Each curing cycle consisted of curing at 150°C for 20 min under an argon atmosphere, and each pyrolysis cycle involved heating at 3°C / min to 1300°C for 1.5 h under an Ar atmosphere. This process converted LPCS into SiC, which then reacted with Ti to form TiC and Ti5Si3C. x A SiC-TiC-Ti5Si3C layer with a thickness of 150 μm was formed. x Multiphase ceramic bonding layer.

[0045] ③ Preparation of environmental barrier / thermal barrier multilayer coating: Atmospheric plasma spraying is used to coat the SiC-TiC-Ti5Si3C substrate. x A Yb₂SiO₅ environmental barrier layer (EBC) with a thickness of 150 μm was deposited on the surface of the multiphase ceramic binder. Subsequently, a yttrium oxide-stabilized zirconia (YSZ) thermal barrier layer with vertical cracks (vertical cracks penetrating the thickness of the thermal barrier layer) was prepared on the EBC surface using plasma physical vapor deposition (PS-PVD). By controlling the PS-PVD process (spraying power 55 kW, deposition temperature 600°C), a YSZ layer (TBC) with a thickness of 200 μm and a vertical crack density of 0.06 cracks / μm was obtained. Figure 1 As shown.

[0046] ④ Construction of a three-dimensional self-healing network: Polycarbosilane containing nano-B4C powder (polycarbosilane modified with nano-B4C powder) was introduced into the vertical cracks of the thermal barrier layer using vacuum impregnation. The impregnation was performed at a vacuum of 50 kPa for 1.5 h, followed by curing at 200°C for 1.5 h. Subsequently, the mixture was pyrolyzed in an Ar atmosphere at a rate of 2°C / min to 1300°C for 1.5 h, transforming the precursor into a SiC-B4C continuous phase. This SiC-B4C continuous phase filled the vertical cracks of the thermal barrier layer, forming a three-dimensional self-healing network. The resulting high-bonding-strength self-healing thermal / environmental barrier coating was then prepared on the surface of the SiC / SiC ceramic matrix composite substrate. The polycarbosilane containing nano-B4C powder was prepared by ball milling nano-B4C powder into liquid polycarbosilane for 4 h, with the volume percentage of nano-B4C powder in the polycarbosilane being 5%.

[0047] Performance Testing: The high-bonding-strength self-healing thermal / environmental barrier coating prepared in this embodiment was tested for bonding strength according to GB / T8642-2002 standard. (SiC-TiC-Ti5Si3C) x The bonding strength (room temperature bonding strength) between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​58 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area is 5%. After corrosion for 100 hours in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss is 0.7 mg / cm³. 2 .

[0048] Example 2 Example 2 is basically the same as Example 1, except that: In step ①, the average laser power was adjusted to 25W, the scanning speed to 800mm / s, the trench depth to 40μm, the width to 15μm, and the spacing between adjacent trenches to 15μm; the thickness of the magnetron sputtered Ti film was adjusted to 150nm.

[0049] In step ②, the amount of nano β-SiC powder added is adjusted to 7 vol%, the amount of micron Ti powder added is adjusted to 5 vol%, and the pyrolysis temperature is adjusted to 1400°C.

[0050] In step ③: the environmental barrier material is changed to Yb2Si2O7 with a thickness of 120μm; the thermal barrier is prepared by atmospheric plasma spraying (APS) with a thickness of 250μm and a vertical crack density of 0.08 cracks / μm.

[0051] In step ④: the precursor is changed to liquid polyborosilicate, the pyrolysis temperature is adjusted to 1200°C, and the SiBCN continuous phase is filled into the vertical crack of the thermal barrier layer to form a three-dimensional self-healing network.

[0052] Performance Testing: The high-bonding-strength self-healing thermal / environmental barrier coating prepared in this embodiment was tested for bonding strength according to GB / T8642-2002 standard. (SiC-TiC-Ti5Si3C) x The bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​63 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area is 3%. After corrosion for 100 hours in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss is 0.6 mg / cm³. 2 .

[0053] Example 3 Example 3 is basically the same as Example 1, except that: In step ①: femtosecond laser processing is used with a power of 10W, a scanning speed of 300mm / s, a trench depth of 20μm, a width of 8μm, and a spacing of 8μm between adjacent trenches; the reactive ion etching time is adjusted to 15min.

[0054] In step ②: repeat the brushing-curing-pyrolysis process 3 times; adjust the pyrolysis heat preservation time to 2 hours.

[0055] In step ③: the TBC layer thickness is increased to 300 μm, and the vertical crack density is 0.04 cracks / μm.

[0056] In step ④: the vacuum impregnation time is adjusted to 2.5 hours.

[0057] Performance Testing: The high-bonding-strength self-healing thermal / environmental barrier coating prepared in this embodiment was tested for bonding strength according to GB / T8642-2002 standard. (SiC-TiC-Ti5Si3C) x The bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​55 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area is 8%. After corrosion for 100 hours in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss is 0.9 mg / cm³. 2 .

[0058] Example 4 Example 4 is basically the same as Example 1, except that: In step ①, the thickness of the Ti film is adjusted to 30 nm by changing the magnetron sputtering time.

[0059] Performance Testing: The high-bonding-strength self-healing thermal / environmental barrier coating prepared in this embodiment was tested for bonding strength according to GB / T8642-2002 standard. (SiC-TiC-Ti5Si3C) xThe bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​45 MPa. After a thermal cycling test at 1500°C (200 cycles), the area of ​​coating peeling is 18%.

[0060] Example 5 Example 5 is basically the same as Example 1, except that: In step ①, the thickness of the Ti film is adjusted to 250 nm by changing the magnetron sputtering time.

[0061] Performance Testing: The high-bonding-strength self-healing thermal / environmental barrier coating prepared in this embodiment was tested for bonding strength according to GB / T8642-2002 standard. (SiC-TiC-Ti5Si3C) x The bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​43 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area is 19%.

[0062] Example 6 Example 6 is basically the same as Example 1, except that: In step ②, the modified LPCS slurry is prepared as follows: using liquid polycarbosilane with a viscosity of 50 mPa·s at 25°C as the matrix, 2 vol% nano β-SiC powder (D50=50nm) is added as a nucleating agent, and 1 vol% micron Ti powder (D50=2μm) is added as an active filler. The mixture is ball-milled for 8 hours to obtain a uniform modified LPCS slurry.

[0063] Performance Testing: The high-bonding-strength self-healing thermal / environmental barrier coating prepared in this embodiment was tested for bonding strength according to GB / T8642-2002 standard. (SiC-TiC-Ti5Si3C) x The bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​40 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area is 22%.

[0064] Example 7 Example 7 is basically the same as Example 1, except that: In step ②, the modified LPCS slurry is prepared as follows: using liquid polycarbosilane with a viscosity of 50 mPa·s at 25°C as the matrix, 8 vol% nano β-SiC powder (D50=50nm) is added as a nucleating agent, and 6 vol% micron Ti powder (D50=2μm) is added as an active filler. The mixture is ball-milled for 8 hours to obtain a uniform modified LPCS slurry.

[0065] Performance Testing: The high-bonding-strength self-healing thermal / environmental barrier coating prepared in this embodiment was tested for bonding strength according to GB / T8642-2002 standard. (SiC-TiC-Ti5Si3C) x The bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​38 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area is 26%.

[0066] Comparative Example 1 Comparative Example 1 is basically the same as Example 1, except that the step of forming the micro-nano composite texture in step ① is omitted. A pure Ti film is directly deposited on the surface of the substrate after removing surface contaminants by DC magnetron sputtering as a chemical bonding transition layer. The sputtering pressure is 0.5 Pa, the power is 150 W, the time is 40 min, and the Ti film thickness is 100 nm. The substrate with the chemical bonding transition layer formed is used to replace the substrate with the micro-nano composite texture and chemical bonding transition layer in Example 1 for subsequent steps.

[0067] Performance Testing: The coatings prepared in this comparative example underwent bonding strength testing according to GB / T 8642-2002 standard, specifically the SiC-TiC-Ti5Si3C coating. x The bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​20 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area is 42%. After corrosion for 100 hours in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss is 2.2 mg / cm³. 2 .

[0068] Comparative Example 2 Comparative Example 2 is basically the same as Example 1, except that in step ②, a polycarbosilane xylene solution (containing 50% polycarbosilane by mass) prepared with solid polycarbosilane was used to replace the modified LPCS slurry in the experiment to form a 150 μm thick adhesive layer; the substrate with this adhesive layer was used to replace the SiC-TiC-Ti5Si3C substrate in Example 1. x The matrix of the multiphase ceramic adhesive layer is then subjected to subsequent steps.

[0069] Performance Testing: The coating prepared in this comparative example underwent bond strength testing according to GB / T 8642-2002 standard. The bond strength between the adhesive layer and the SiC / SiC composite matrix was 33 MPa. After a 1500°C thermal cycling test (200 cycles), the coating peeling area was 37%. After 100 hours of corrosion in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss was 1.8 mg / cm³. 2 .

[0070] Comparative Example 3 Comparative Example 3 is basically the same as Example 1, except that in step ③, the environmental barrier / thermal barrier multilayer coating is prepared by atmospheric plasma spraying and deposited in one go, without controlling the formation of vertical crack structure, i.e., without vertical crack structure; other steps are the same as in Example 1.

[0071] Performance Testing: The coatings prepared in this comparative example underwent bonding strength testing according to GB / T 8642-2002 standard, specifically the SiC-TiC-Ti5Si3C coating. x The bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix was 56 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area was 22%. After corrosion for 100 hours in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss was 1.5 mg / cm³. 2 .

[0072] Comparative Example 4 Comparative Example 4 is basically the same as Example 1, except that the self-healing network construction in step ④ is omitted, so that the TBC layer maintains the original vertical crack state; the other steps are the same as in Example 1.

[0073] Performance Testing: The coatings prepared in this comparative example underwent bonding strength testing according to GB / T 8642-2002 standard, specifically the SiC-TiC-Ti5Si3C coating. x The bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix was 58 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area was 23%. After 100 hours of corrosion in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss was 3.1 mg / cm³. 2 .

[0074] Comparative Example 5 Comparative Example 5 is basically the same as Example 1, except that: in step ①, the magnetron sputtering transition layer is replaced with a deposited Cr film (non-active metal); in step ②, the modified LPCS slurry does not contain micron-sized Ti powder; other steps are the same as in Example 1.

[0075] Performance Testing: The coating prepared in this comparative example underwent bond strength testing according to GB / T 8642-2002 standard. The bond strength between the adhesive layer and the SiC / SiC composite matrix was 24 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area was 39%. After corrosion for 100 hours in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss was 1.9 mg / cm³. 2 .

[0076] Comparative Example 6 Comparative Example 6 is basically the same as Example 1, except that: In step ②: In the modified LPCS slurry, nano β-SiC is replaced with nano Al2O3 (D50=60nm), and micron Ti powder is replaced with micron Hf powder (D50=2.5μm).

[0077] In step ③: the environmental barrier layer is a composite coating of Yb2SiO5 and Yb2Si2O7 mixed in a mass ratio of 1:1, with a thickness of 180μm; the thermal barrier layer material is changed to Gd2Zr2O7, with a thickness of 220μm.

[0078] In step ④: the impregnation precursor is changed to liquid polyborosilicate.

[0079] Performance Testing: The coating prepared in this comparative example underwent bonding strength testing according to GB / T 8642-2002 standard. The bonding strength between the adhesive layer and the SiC / SiC composite matrix was 41 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area was 17%. After corrosion for 100 hours in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss was 1.3 mg / cm³. 2 .

[0080] Comparative Example 7 Comparative Example 7 is basically the same as Example 1, except that: ① Substrate Interface Pretreatment: The substrate selected was a SiC / SiC ceramic matrix composite material with a deposited BN interface layer. First, the substrate was ultrasonically cleaned with acetone for 30 min, and then dried in a vacuum drying oven at 120°C for 1.5 h to remove surface contaminants. Next, a femtosecond laser processing system was used to construct a micro-groove array on the substrate surface. The laser wavelength was 515 nm, the laser pulse width was 300 fs, the average laser power was 15 W, the scanning speed was 500 mm / s, and the scan was repeated 5 times. The micro-groove depth was 30 μm, the width was 10 μm, and the distance between adjacent grooves was 10 μm. Subsequently, reactive ion etching was performed using CF4 as the reactive gas, with a power of 200 W and a time of 10 min to form a micro-nano composite texture on the substrate surface. This micro-nano composite textured substrate was then used to replace the substrate with the micro-nano composite texture and chemical bonding transition layer in Example 1 for subsequent steps.

[0081] Performance testing: The bonding strength of the prepared coatings in this comparative example was tested according to GB / T 8642-2002 standard, for SiC-TiC-Ti5Si3C. xThe bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​30 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area is 32%. After corrosion for 100 hours in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss is 1.6 mg / cm³. 2 .

[0082] Comparative Example 8 Comparative Example 8 is basically the same as Example 1, except that: In step ②, the modified LPCS slurry is prepared as follows: using liquid polycarbosilane with a viscosity of 50 mPa·s at 25°C as the matrix, 3 vol% micron Ti powder (D50=2μm) is added as the active filler, and ball milling is performed for 8 hours to obtain a uniform modified LPCS slurry.

[0083] Performance testing: The bonding strength of the prepared coatings in this comparative example was tested according to GB / T 8642-2002 standard, for SiC-TiC-Ti5Si3C. x The bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​35 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area is 24%. After corrosion for 100 hours in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss is 1.6 mg / cm³. 2 .

[0084] Comparative Example 9 Comparative Example 9 is basically the same as Example 1, except that: In step ②, the modified LPCS slurry is prepared as follows: using liquid polycarbosilane with a viscosity of 50 mPa·s at 25°C as the matrix, 5 vol% nano β-SiC powder (D50=50nm) is added as a nucleating agent, and ball milling is performed for 8 hours to obtain a uniform modified LPCS slurry.

[0085] Performance testing: The bonding strength of the prepared coatings in this comparative example was tested according to GB / T 8642-2002 standard, for SiC-TiC-Ti5Si3C. x The bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix was 36 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area was 23%. After corrosion for 100 hours in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss was 1.5 mg / cm³. 2 .

[0086] Comparative Example 10 Comparative Example 10 is basically the same as Example 1, except that: ② Preparation of the adhesive layer: Weigh titanium powder and silicon powder in a molar ratio of 3:2. Based on the total mass of titanium and silicon powder, add 6 times the amount of sodium chloride as a reaction aid. Ball mill the powder in anhydrous ethanol for 24 hours. After ball milling, the mixture was dried and then passed through a 200-mesh sieve to obtain the raw material powder required for coating preparation. The substrate with a micro-nano composite texture and chemically bonded transition layer on the surface obtained in step ① was placed in an alumina crucible, and the above raw material powder was used to completely embed the substrate. The alumina crucible was placed in a tube furnace, heated to 500℃ and held for 1 hour to remove any crystal water that may be present in the mixed powder, and then heated to 1200℃ and held for 2 hours. After that, it was cooled to room temperature with the furnace, and argon gas was supplied throughout the heat treatment process. The excess powder adhering to the surface of the substrate after heat treatment was removed by washing with 80℃ deionized water. After drying, a TiC-Ti3SiC2-Ti5Si3C coating was obtained on the basis of the micro-nano composite texture and chemically bonded transition layer on the surface of the SiC / SiC composite substrate. x A Ti-Si-C composite adhesive layer with this structure was used. The SiC / SiC composite matrix in Example 1 with this composite adhesive layer was replaced. x Subsequent steps are performed on the SiC / SiC composite matrix with the multiphase ceramic adhesive layer.

[0087] Performance testing: The bonding strength of the prepared coatings in this comparative example was tested according to GB / T 8642-2002 standard, for SiC-TiC-Ti5Si3C. x The bonding strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​51 MPa. After a thermal cycling test at 1500°C (200 cycles), the coating peeling area is 10%. After corrosion for 100 hours in a 1500°C environment with 90 vol% water vapor and 10 vol% oxygen, the weight loss is 1.0 mg / cm³. 2 .

[0088] The performance test results of the coatings prepared in each embodiment and comparative example of the present invention are shown in Table 1.

[0089] Table 1: Performance comparison results of the examples / comparative examples.

[0090] In Table 1, the symbol " / " indicates that the parameter does not exist or that the performance metric has not been tested.

[0091] As can be seen from the above embodiments and comparative examples, the embodiments of the present invention, through the synergistic interface design of "mechanical anchoring-chemical bonding," in-situ molding of the gradient adhesive layer, and construction of a three-dimensional self-healing network, achieve a room temperature bonding strength of ≥50MPa at the substrate / adhesive layer interface, a coating peeling area of ​​≤10% after 200 cycles at 1500°C, and an oxidation weight gain of ≤1.0mg / cm³ after 100 hours of water-oxygen corrosion at 1500°C. 2 It exhibits excellent resistance to thermal shock and water-oxygen corrosion. Examples 4 to 7 systematically demonstrate the correlation between key parameters (Ti film thickness, modified LPCS slurry composition) and performance: once deviating from the preferred range, the bonding strength drops significantly to below 50 MPa, and the thermal shock resistance deteriorates simultaneously. In Comparative Examples 1 and 2, the lack of a "mechanical anchoring-chemical bonding" synergistic interface design and gradient adhesive layer design resulted in a sharp decrease in the bonding strength between the SiC adhesive layer and the substrate, leading to severe coating peeling under thermal shock conditions. In Comparative Example 3, the thermal barrier layer lacked vertical cracks and a self-healing network, resulting in significant coating peeling under thermal shock conditions. In Comparative Example 4, the thermal barrier layer had vertical cracks but lacked a self-healing network. The large difference in thermal expansion coefficients between the environmental barrier layer and the thermal barrier layer caused the failure cracks to propagate along the vertical cracks, penetrating the environmental barrier layer. Water and oxygen entered the environmental barrier layer along the vertical cracks, weakening the environmental barrier layer's resistance to water and oxygen corrosion, resulting in high weight loss under water and oxygen corrosion. Comparative Examples 5 and 6 altered the substrate / adhesive layer synergistic interface design and gradient adhesive layer design, leading to a decrease in the bonding strength between the substrate and the adhesive layer, resulting in severe coating peeling under thermal shock conditions. Comparative Example 7 (without a Ti transition layer) demonstrates that high-strength bonding cannot be achieved solely through mechanical anchoring; Comparative Examples 8 and 9 (single slurry composition) show that nano-β-SiC and micron-sized Ti powder have a synergistic effect in inhibiting shrinkage and enhancing bonding, and neither is dispensable; based on the same "mechanical anchoring-chemical bonding" synergistic interface design of this invention, Comparative Example 10 has a TiC-Ti3SiC2-Ti5Si3C... x The bonding strength between the Ti-Si-C composite adhesive layer and the substrate is still significantly lower than that achieved in the preferred embodiment of the present invention.

[0092] In summary, this invention prepares a high-bonding-strength self-healing thermal / environmental barrier coating by using a synergistic interface design of "mechanical anchoring-chemical bonding", in-situ molding of gradient adhesive layer and construction of three-dimensional self-healing network, which significantly improves the service performance of SiC / SiC composite matrix.

[0093] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-healing thermal / environmental barrier coating with high bonding strength, characterized in that: The high-bonding-strength self-healing thermal / environmental barrier coating, from the SiC / SiC composite matrix outwards, sequentially includes a micro / nano composite texture and a chemically bonded transition layer, and a SiC-TiC-Ti5Si3C layer. x Multiphase ceramic bonding layer, environmental barrier layer and thermal barrier layer with vertical cracks; The vertical cracks in the thermal barrier layer are filled with a self-healing phase.

2. The self-healing thermal / environmental barrier coating according to claim 1, characterized in that: The micro-nano composite texture and chemically bonded transition layer are formed by laser processing, reactive ion etching and magnetron sputtering. The SiC-TiC-Ti5Si3C x The multiphase ceramic bonding layer is formed by integrated pyrolysis of a modified liquid polycarbosilane slurry containing liquid polycarbosilane, nano β-SiC powder and micron Ti powder; The environmental barrier layer is a rare earth silicate environmental barrier layer. The thermal barrier layer is a ceramic thermal barrier layer; and / or The self-healing phase is a SiC-B4C and / or SiBCN self-healing phase.

3. A method for preparing a self-healing thermal / environmental barrier coating with high bonding strength, characterized in that, The method includes the following steps: (1) A micro-nano composite texture was constructed on the surface of the SiC / SiC composite matrix and a Ti transition layer was deposited to obtain a micro-nano composite texture and chemical bonding transition layer on the surface of the SiC / SiC composite matrix. (2) The SiC / SiC composite matrix treated in step (1) was subjected to integrated pyrolysis treatment using modified liquid polycarbosilane slurry to obtain SiC-TiC-Ti5Si3C based on the micro-nano composite texture and chemical bonding transition layer. x Multiphase ceramic bonding layer; (3) In SiC-TiC-Ti5Si3C x An environmental barrier layer and a thermal barrier layer with vertical cracks are sequentially prepared on the surface of a multiphase ceramic bonding layer. (4) The precursors of SiC-B4C and / or SiBCN, which are pyrolysis products, are introduced into the vertical cracks of the thermal barrier layer and cured and pyrolyzed, so that the vertical cracks of the thermal barrier layer are filled with SiC-B4C and / or SiBCN self-healing phases, thereby obtaining the high bonding strength self-healing thermal / environmental barrier coating on the SiC / SiC composite matrix.

4. The preparation method according to claim 3, characterized in that, In step (1): The SiC / SiC composite matrix is ​​a SiC / SiC ceramic matrix composite material with continuous silicon carbide fibers as the reinforcing phase and silicon carbide ceramics as the matrix phase. Preferably, the continuous silicon carbide fiber surface of the SiC / SiC ceramic matrix composite material has an interface layer of pyrolytic carbon, silicon carbide and / or boron nitride. Preferably, the density of the SiC / SiC ceramic matrix composite material is 2.1-2.8 g / cm³. 3 .

5. The preparation method according to claim 3, characterized in that, In step (1): The method for constructing the micro-nano composite texture is as follows: first, a micro-groove array is processed on the surface of the SiC / SiC composite matrix using a femtosecond laser; then, a nanoscale rough structure is etched on the inner wall of the micro-groove using reactive ion etching, thereby constructing a micro-nano composite texture on the surface of the SiC / SiC composite matrix. Preferably, the femtosecond laser has a wavelength of 515nm, a pulse width of 100-500fs, an average laser power of 5-30W, a scanning speed of 100-1000mm / s, and 3-10 scans. Preferably, the depth of the micro-grooves in the micro-groove array is 10-50 μm and the width is 5-20 μm; Preferably, the reactive ion etching uses CF4 or SF4 as the reactive gas, the gas flow rate is 20-50 sccm, the power of the reactive ion etching is 100-300 W, and the time is 5-15 min; and / or A Ti transition layer was deposited by DC magnetron sputtering; Preferably, the sputtering gas pressure of DC magnetron sputtering is 0.3-0.8 Pa, the power is 100-200 W, and the time is 20-60 min; Preferably, the thickness of the Ti transition layer is 50-200 nm.

6. The preparation method according to claim 3, characterized in that, In step (2): The modified liquid polycarbosilane slurry comprises liquid polycarbosilane, nano-β-SiC powder, and micron-sized Ti powder; Preferably, the viscosity of the liquid polycarbosilane is 20-100 mPa·s, and the particle size D of the nano-β-SiC powder is... 50 The particle size D of the micron-sized Ti powder is 20-100 nm. 50 1-3μm; Preferably, the modified liquid polycarbosilane slurry contains 3-7 vol% nano-β-SiC powder by volume, and / or the modified liquid polycarbosilane slurry contains 2-5 vol% micron-sized Ti powder by volume. The integrated pyrolysis process involves introducing the modified liquid polycarbosilane slurry into the micro-nano composite texture and chemical bonding transition layer on the surface of the SiC / SiC composite matrix by brushing, dip coating, or vacuum impregnation, followed by curing and pyrolysis. Preferably, the integrated pyrolysis process is repeated 1 to 3 times; Preferably, the curing is performed at 100-200°C for 10-30 min under a nitrogen and / or argon atmosphere, and the pyrolysis is performed at 1100-1400°C for 1-2 h under an argon atmosphere with a heating rate of 1-5°C / min; and / or The SiC-TiC-Ti5Si3C x The thickness of the multiphase ceramic bonding layer is 50-200μm.

7. The preparation method according to claim 3, characterized in that, In step (3): The environmental barrier layer is prepared by thermal spraying, preferably one or more of atmospheric plasma spraying, supersonic flame spraying, suspension plasma spraying, and plasma physical vapor deposition. The environmental barrier layer is a rare earth silicate environmental barrier layer, preferably a Yb2SiO5 and / or Yb2Si2O7 rare earth silicate environmental barrier layer. The thickness of the environmental barrier layer is 100-200 μm; A thermal barrier layer with vertical cracks is prepared on the surface of the environmental barrier layer using one or more of the following methods: atmospheric plasma spraying, electron beam physical vapor deposition, and plasma physical vapor deposition. The thermal barrier layer is a ceramic thermal barrier layer. Preferably, the ceramic thermal barrier layer is made of one or more of zirconium oxide, hafnium oxide, rare earth zirconate, and rare earth hafnium salt, and / or the ceramic thermal barrier layer is made of one or more of rare earth oxide modified zirconium oxide, hafnium oxide, rare earth zirconate, and rare earth hafnium salt. Preferably, the rare earth oxide is Y2O3 and / or Yb2O3. The thickness of the thermal barrier layer is 100-400 μm; and / or The density of the vertical cracks is 0.005~2 cracks / μm.

8. The preparation method according to claim 3, characterized in that, In step (4): Precursors with SiC-B4C and / or SiBCN pyrolysis products are introduced into vertical cracks in the thermal barrier layer by vacuum impregnation. The vacuum impregnation is performed under a vacuum of 10-100 kPa for 0.5-3 hours. The curing process involves curing at 100-300°C for 1-3 hours. The pyrolysis is performed by heating to 1100-1400°C for 1-2 hours in an argon atmosphere at a heating rate of 1-3°C / min; and / or The precursors of the pyrolysis products SiC-B4C and / or SiBCN are boron-modified polycarbosilane, polycarbosilane containing nano-B4C powder, and / or polyborosilicate.

9. The preparation method according to any one of claims 3 to 8, characterized in that: The high-bonding-strength self-healing thermal / environmental barrier coating comprises SiC-TiC-Ti5Si3C x The room temperature bond strength between the multiphase ceramic adhesive layer and the SiC / SiC composite matrix is ​​≥50 MPa; and / or The high-bonding-strength self-healing thermal / environmental barrier coating exhibits a peeling area of ​​≤10% after 200 thermal cycles at 1500°C and an oxidation weight gain of ≤1.0 mg / cm³ after 100 hours of water-oxygen corrosion at 1500°C. 2 .

10. A self-healing thermal / environmental barrier coating with high bonding strength prepared by the preparation method according to any one of claims 3 to 9.

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