A method for repairing ceramic and ceramic matrix composites

Abstract

The application discloses a kind of ceramic and ceramic matrix composite repair method, belong to laser repair technical field.The application is prepared into repair slurry by core-shell structure coated powder, filled to material damage area, again Si powder or Si alloy powder is laid, laser scanning processing is carried out under protective atmosphere.Molten Si and carbon shell of coated powder in-situ reaction generates ceramic phase, realizes dense repair of damage area.The application process is simple, local heat input is small, repair interface is firmly combined, and can be adapted to SiC ceramic, C f / SiC, SiC f / SiC and various materials.Such as, after testing, the bending strength after repair can be restored to more than 80% of the intact sample, is suitable for efficient, accurate, in-situ repair of high-temperature structural ceramic components, and has high engineering application value.

Description

Technical Field

[0001] This invention relates to the fields of advanced ceramic materials and laser manufacturing technology, and more specifically, to a method for repairing ceramics and ceramic matrix composites. Background Technology

[0002] Ceramic and ceramic matrix composite materials, due to their high melting point, high hardness, high temperature resistance, wear resistance, corrosion resistance, good oxidation resistance, and low density, have been widely used in aerospace, energy, and defense industries, especially in engine hot-end components, gas turbine blades, and nuclear reactor cladding. However, these materials generally suffer from high brittleness, limited impact damage resistance, and high processing difficulty, making them prone to defects such as cracks, voids, wear, and localized damage during preparation, assembly, and service. These defects can disrupt the material's structural integrity, weaken its mechanical properties and service stability, and in severe cases, even lead to component failure. Therefore, developing efficient and reliable damage repair technologies is of great significance for reducing the maintenance and replacement costs of ceramic and ceramic matrix composite components, ensuring the structural integrity and safety of components, and extending their service life.

[0003] Currently, repair methods for ceramics and ceramic matrix composites mainly include polymer precursor conversion ceramics (PDCs), chemical vapor deposition (CVD), reactive infiltration (RMI), and active brazing. While PDCs, CVD, and RMI can achieve damage repair to some extent, they typically suffer from long processing cycles and high energy consumption. More importantly, these methods often involve processing the entire component in a furnace, making rapid, in-situ repair of localized damage impossible. This significantly limits their application in aerospace components. Although active brazing technology is simple and operates at low temperatures, the significant differences in physicochemical properties between metals and ceramics make it difficult to achieve satisfactory bonding results.

[0004] Patent 1 CN 119371232 A discloses a precursor ceramic adhesive repair agent, its preparation method, and its repair method. It uses PMHS, D4Vi, and nano-TiB2 as its main components. The repair agent first penetrates into the ceramic crack or wear area in a liquid state, and then undergoes cross-linking curing and high-temperature pyrolysis to transform into a ceramic phase in situ, achieving defect filling and performance restoration. However, this method is highly dependent on high-temperature heat treatment, and shrinkage and porosity are easily generated during pyrolysis. Furthermore, interfacial mismatch and insufficient long-term service stability may still exist between the repair layer and the base material.

[0005] Reference 1, "Pore defects repair of CCF / SiC composites fabricated by additive manufacturing," employs an integrated process combining chemical vapor deposition and reactive infiltration to grow SiC nanowires in situ within the material to fill pores and achieve damage repair. While this method shows some effectiveness in pore repair, its process relies on overall in-furnace processing, resulting in long repair cycles and high energy consumption. It also struggles to achieve rapid, targeted repair of localized damage to components, thus lacking flexibility in practical engineering applications.

[0006] Reference 2, "Optimizing Si-C reaction bonding for SiC joining: Effects offiller composition, thickness, and surface roughness on joint strength," utilizes Si-C reaction bonding technology to achieve SiC bonding by infiltrating pre-fabricated SiC and C filler strips with molten Si. The limitation of this method is that it is also a monolithic in-furnace process, unable to achieve rapid, localized repair, resulting in poor application flexibility. Furthermore, traditional carbon sources often do not react completely with Si, leaving residual C in the repaired area, which adversely affects material properties.

[0007] Patent 2CN119304505A proposes a method for patching and repairing silicon carbide ceramic matrix composite (CMC-SiC) parts for aero-engines. It uses CMC-SiC patches to cover cracks, corrosion pits, and fiber breakage areas, and performs laser surface texturing on the contact surface between the patch and the base material. Subsequently, a brazing filler metal is applied, and the parts are connected via vacuum brazing to reconstruct the force transmission path in the damaged areas and restore the strength and serviceability of the parts. However, the significant differences in physicochemical properties between the ceramic matrix and the metal result in poor wettability of the metal brazing filler metal on the ceramic matrix surface, making it difficult to form a stable and reliable connection interface.

[0008] Laser processing technology offers new avenues for the efficient repair of ceramics and ceramic matrix composites due to its advantages such as concentrated energy, rapid heating and cooling, good process controllability, and ease of achieving precise localized processing. However, this technology still faces challenges in practical applications. For example, the method of directly melting silicon powder with a carbon source using lasers suffers from problems such as violent reactions, difficulty in controlling the temperature field, and weak bonding between the new phase and the matrix; while directly using SiC powder is difficult to form a dense repair due to its high melting point and easy decomposition.

[0009] Meanwhile, core-shell powders, as an advanced material design concept, offer a new direction for solving the aforementioned problems. These materials are typically composed of two different substances tightly bonded together through physical or chemical interactions, forming a composite structure of a core and an outer shell. In this structure, the core and shell can produce a synergistic effect, thereby exhibiting comprehensive performance advantages that cannot be matched by a single material or simple alloy. Designing a core-shell powder suitable for laser repair processes holds promise for solving these problems.

[0010] Patent CN121288745A discloses a core-shell structured ceramic powder and its preparation method and system. This patent introduces ytterbium and silicon sources into a suspension system containing SiO2 cores, and controls the pH, reaction temperature, and subsequent process parameters such as washing, calcination, and ball milling to allow Yb2Si2O7 to deposit and grow on the SiO2 surface, ultimately forming a core-shell structure. It points out that this core-shell structure can achieve synergistic regulation of composition and interface through the functional division of the core and shell, which not only helps improve the phase stability and environmental adaptability of the material, but also improves the uniformity of component distribution, thereby enhancing the material's service performance in high-temperature and complex environments.

[0011] Reference 3, "Enhancing surface quality in laser powder bed fusion using core-shell structured powder with micrometer-sized metal core and TiO2 nanoparticle shell," employs a core-shell structured composite powder. AISI 420J2 stainless steel micron-sized particles serve as the core, with TiO2 nanoparticles uniformly coated on the surface to form a shell. Research shows that this core-shell structured powder significantly reduces the surface roughness of the formed parts and effectively suppresses defects during laser powder bed fusion (LPBF) forming. Furthermore, these improvements remain stable in multilayer formed samples with 20–200 layers, fully demonstrating the superiority of core-shell structured powders in the field of laser additive manufacturing.

[0012] Therefore, there is an urgent need to develop a novel repair method that integrates the advantages of laser technology with the design concepts of core-shell materials to achieve efficient repair of damaged areas in ceramics and ceramic matrix composites. Through innovative material design and process control, an interface matching the properties of the matrix can be formed in the damaged area, effectively overcoming the shortcomings of existing repair technologies and meeting the rapid repair needs of critical components during service. Summary of the Invention

[0013] To overcome the shortcomings of the prior art, the present invention provides a method for repairing ceramics and ceramic matrix composites, the method specifically including the following steps: Step S1: Prepare the repair slurry: Add the coated powder to an inorganic solvent to obtain the repair slurry; Step S2, Introduce repair slurry: Introduce and fill the damaged area of ​​ceramics and ceramic matrix composites with the repair slurry prepared in step S1; Step S3, Laser Repair: Si powder or Si alloy powder is laid on the surface of the damaged area that has been introduced and filled with repair slurry, and the surface of the damaged area with Si powder or Si alloy powder is laser scanned in a protective atmosphere.

[0014] Compared with existing technologies, this invention achieves efficient repair of damaged areas in ceramics and ceramic matrix composites through a complete process involving the preparation of repair slurry, filling the damaged area, laying Si powder or Si alloy powder, and laser scanning. This process uses core-shell coated powder as the repair material and a laser as the local heat source. The melted silicon reacts in situ with the carbon layer in the coated powder to generate a ceramic phase. This allows for defect filling and densification without damaging the matrix, forming a repair area that is firmly bonded to the parent material and structurally continuous. The overall process is simple and controllable, suitable for rapid in-situ repair of various localized damages, providing a stable and reliable technical solution for component performance restoration and service life extension.

[0015] In one possible implementation, the ceramic and ceramic matrix composite are selected from SiC ceramics, C... f / SiC composite materials, SiC f One of the SiC composite materials and their modified ceramic matrix composite materials.

[0016] Compared with existing technologies, this invention limits the repair targets to SiC ceramics and C. f / SiC、SiC f SiC and modified composite materials cover mainstream high-temperature structural ceramic systems, improve the versatility and engineering applicability of the method, meet the component repair needs of aerospace, energy and other fields, and at the same time match the repair phase with the matrix composition and thermophysical properties, reduce the risk of interface mismatch, and ensure the stability and reliability of the repaired structure.

[0017] In one possible implementation, in step S1, the coated powder comprises 40-80 mol.% of a core ceramic phase and 20-60 mol.% of C, and the particle size of the coated powder is 2-40 μm. The core ceramic phase is selected from one of SiC, HfC, TiC, ZrB2 and HfB2.

[0018] Compared with existing technologies, this invention provides a stable and controllable carbon source and ceramic skeleton by regulating the ceramic phase, carbon content and particle size of the coated powder, ensuring sufficient in-situ reaction and continuous and dense repair phase; it selects a high-melting-point ceramic core to improve the high-temperature performance and environmental adaptability of the repair area; and it optimizes the dispersion and filling effect with reasonable particle size to reduce defects and improve the strength and stability of the repair layer.

[0019] In one possible implementation, in step S1, the solid volume fraction of the repair slurry is 30-60 vol.%. The inorganic solvent is deionized water or anhydrous ethanol, and after the coated powder is added to the inorganic solvent, it is subjected to magnetic stirring for 8-15 hours.

[0020] Compared with existing technologies, this invention, by limiting the solid content, solvent, and stirring time of the slurry, produces a repair slurry that is uniformly dispersed, has moderate fluidity, and leaves no residue. This slurry can smoothly penetrate into minute defects and ensure sufficient reaction raw materials. Thorough stirring avoids powder agglomeration and sedimentation, improves slurry consistency, and provides raw material guarantee for uniform filling and stable laser reaction.

[0021] In one possible implementation, in step S2, the repair slurry is introduced by impregnation or brushing, wherein the impregnation method is selected from vacuum impregnation, pressure impregnation, or vacuum-pressure impregnation. This invention employs impregnation or brushing to introduce the slurry and provides multiple impregnation methods to adapt to damage of different sizes, depths, and morphologies, improving process flexibility and filling fullness. This allows the slurry to fully penetrate into internal cracks and pores, effectively filling deep defects and laying the foundation for forming a dense, continuous repair layer.

[0022] In one possible implementation, in step S3, the Si powder or Si alloy powder is laid by dry powder laying or brushing slurry, and the thickness of the laying is 0.5-2 mm, wherein the particle size of the Si powder or Si alloy powder is 5-100 μm. The Si alloy powder is selected from at least one of Si-Y alloy powder, Si-Ti alloy powder, Si-Zr alloy powder, Si-Hf alloy powder, Si-Mo alloy powder, and Si-Al alloy powder.

[0023] Compared with existing technologies, this invention ensures uniform melting, full penetration and efficient reaction of silicon source by limiting the laying method, thickness, particle size and silicon alloy type; the laying of dry powder and slurry takes into account efficiency and uniformity, appropriate parameters improve wettability and fluidity, and silicon alloy optimizes reaction activity and interfacial bonding, thereby enhancing the density and reliability of the repair layer.

[0024] In one possible implementation, when applying Si powder or Si alloy powder by brushing, the solid volume fraction of the slurry is 30-60 vol.% Si powder or Si alloy powder, and the slurry is stirred or ball-milled for 8-15 hours. By controlling the solid content of the silicon source slurry and the stirring and ball-milling time, a layered slurry with good formability and uniform dispersion is obtained, avoiding powder agglomeration, ensuring synchronous and uniform melting, penetration and reaction under laser irradiation, reducing local defects, and improving the uniformity of the repair layer structure and the quality of interface bonding.

[0025] In one possible implementation, in step S3, the protective atmosphere is selected from vacuum, argon, and nitrogen, and the vacuum level is <500 Pa. This invention uses vacuum, argon, or nitrogen for protection and controls the vacuum level to avoid high-temperature oxidation, nitriding, and impurity contamination, ensuring the purity of the reaction system and reducing impurities and porosity. A suitable vacuum level promotes gas removal and silicon penetration, improving the purity and density of the repair phase, ensuring a stable repair process and reliable repair performance.

[0026] In one possible implementation, the parameters of the laser scanning process in step S3 are as follows: laser power of 300-800 W, scanning speed of 100-800 mm / min, spot diameter of 0.5-4 mm, and overlap rate of 30-80%.

[0027] Compared with existing technologies, this invention, through reasonable matching and precise control of laser power, scanning speed, spot diameter, and overlap rate, can form a stable, uniform, and controllable temperature field in the repair area. This ensures that Si powder or Si alloy powder fully melts, rapidly penetrates, and undergoes a full in-situ reaction with the carbon shell in the coating powder. Appropriate laser power avoids overheating damage to the substrate and powder ablation; suitable scanning speed ensures sufficient reaction and a small heat-affected zone; and reasonable spot size and overlap rate achieve full coverage of the repair area, with no missed scans and no excessive remelting. This results in a uniform and dense repair layer with few defects and high interfacial bonding strength. The overall repair process is stable and controllable, with strong process repeatability, significantly improving the reliability of repair quality and performance recovery.

[0028] In one possible implementation, a pretreatment of the ceramic and ceramic matrix composite material is included before step S2. The pretreatment is selected from one or more of the following: ultrasonic cleaning with anhydrous ethanol, solvent spraying or wiping, compressed gas purging, vacuum suction, soft brush cleaning, hot air drying, plasma cleaning and laser cleaning. After the pretreatment, the ceramic and ceramic matrix composite material is dried. It also includes step S4, post-processing: the ceramic and ceramic matrix composite material that have been laser-scanned are naturally cooled to room temperature, and then the surface is polished.

[0029] The pretreatment process removes contaminants and debris, ensuring a clean and dry interface and improving adhesion. The posttreatment process involves cooling and polishing to eliminate stress, improve surface quality, and form a complete closed-loop process, thereby enhancing the stability and performance recovery of the repaired interface.

[0030] Compared with the prior art, the present invention has the following advantages: 1. Achieve in-situ reaction-based dense repair: The surface Si or Si alloy is melted by laser and penetrated into the pre-placed core-shell structure-coated powder, which reacts in-situ with the carbon shell to generate a ceramic phase, achieving dense filling and high-strength interfacial bonding of the damaged area, and efficiently restoring the structural integrity of the material.

[0031] 2. Controllable reaction process and interface: Using core-shell structured coated powder as a uniform and controllable carbon source, it reacts and melts with Si or Si alloy under laser action. The carbon source content, distribution state and reaction contact area can be precisely controlled, making the in-situ reaction process stable, controllable and uniform.

[0032] 3. Significantly improves interface bonding performance: A dense, continuous, and firmly bonded repair interface is formed between the repair layer and the substrate, which greatly improves the mechanical properties of the repaired area, effectively avoids problems such as interface mismatch and stress concentration, and reduces the risk of secondary damage.

[0033] 4. Strong process adaptability and high flexibility: Using laser local heating, it can achieve point-to-point, rapid and precise repair of damaged areas. The heat input is controllable and the heat-affected zone is small. It is suitable for complex structural components and on-site in-service repair, breaking through the limitations of traditional furnace-based overall repair.

[0034] 5. Stable repair quality and high reliability: The repaired area has uniform structure and controllable composition, with high performance matching with the base material. The mechanical properties are significantly restored after repair, which can meet the engineering requirements under harsh working conditions such as high temperature and load. Attached Figure Description

[0035] Figure 1 A flowchart for repairing ceramics and ceramic matrix composites.

[0036] Figure 2 A schematic diagram illustrating the mechanism for repairing ceramics and ceramic matrix composites. Detailed Implementation

[0037] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not intended to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the claims of the present invention.

[0038] It should be noted that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0039] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In some instances, terms having a conventional meaning are defined herein for clarification or ease of reference, and such definitions should not be construed as indicating a significant difference from conventional understanding in the art. The technical methods described or referenced herein are generally well understood by those skilled in the art and employed by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments shall be performed according to the manufacturer's instructions and parameters.

[0040] Figure 1 This flowchart illustrates the entire process of repairing ceramics and ceramic matrix composites, clearly demonstrating the steps from sample pretreatment, repair slurry preparation, introduction of coating powder, Si or Si alloy powder application, laser scanning repair, to post-treatment polishing. The diagram visually presents the connections and sequence of each step, clarifies the introduction path of the repair materials and key process nodes, facilitating understanding of the operational flow and process logic of this invention. It highlights the invention's simple process, in-situ implementation capability, and suitability for rapid on-site repair.

[0041] Figure 2 This diagram illustrates the mechanism of repairing ceramics and ceramic matrix composites, revealing the repair principle of core-shell structured powder under laser irradiation. The diagram shows the entire process: pre-placed core-shell structured powder coating in the damaged area, molten infiltration of Si or Si alloy under laser irradiation, in-situ reaction with the carbon shell to form a ceramic phase, and finally, the formation of a dense repair layer. This diagram visually reflects the infiltration behavior of molten silicon, the in-situ reaction path, and the formation mechanism of the repair layer. It clearly demonstrates the principle of defect filling, interfacial bonding, and microstructural densification achieved through the synergistic effect of the core-shell structure and laser, providing intuitive evidence for demonstrating the reliable repair effect, strong interfacial bonding, and uniform and dense repair layer of this invention.

[0042] Example 1 This embodiment provides a repair process for ceramics and ceramic matrix composites, specifically as follows: 1. Sample pretreatment: Pretreatment of C samples containing cracks... f The SiC sample was ultrasonically cleaned in anhydrous ethanol for 30 min, and then dried in an oven at 75 ℃ for 8 h to remove surface contaminants and debris. 2. Preparation of repair slurry: Add 40% SiC@C powder (by volume), 1% polyvinyl alcohol binder (by mass), and 1% sodium carboxymethyl cellulose dispersant (by mass) to deionized water, and stir magnetically for 12 hours to form a uniform repair slurry. 3. Introducing coating powder: The repair slurry is impregnated with the cracked substrate using a vacuum impregnation method, and then dried in a 75 ℃ oven for 8 h; 4. Laser repair: A 1.0 mm thick Si powder layer with a particle size of 5 μm is laid on the damaged surface after impregnation. Then, under argon protection, the laid area is scanned and repaired using parameters of laser power of 400 W, scanning speed of 100 mm / min, spot diameter of 3 mm, and overlap rate of 50%. 5. Post-processing: After the laser scanning is completed, allow the area to be repaired to cool naturally to room temperature, and then use 800-grit sandpaper to polish the surface to make it smooth.

[0043] The mechanical properties of the specimens before and after repair were tested using the three-point bending method, with a span of 30 mm and a loading rate of 0.5 mm / min. The test results showed that the flexural strength of the unrepaired damaged specimen was only 285 MPa, indicating a significant decrease in strength due to the damage. After repair using the method of this invention, the flexural strength of the specimen was significantly increased to 403 MPa, recovering to 82.4% of that of the unrepaired specimen (489 MPa). This demonstrates that the repair method can effectively compensate for defects, restore the structural load-bearing capacity, and achieve significant repair results.

[0044] Example 2 This embodiment provides a repair process for ceramics and ceramic matrix composites, specifically as follows: 1. Sample pretreatment: Pretreatment of SiC samples containing notch damage. f The SiC sample was ultrasonically cleaned in anhydrous ethanol for 30 min, and then dried in an oven at 75 ℃ for 8 h to ensure the damaged area was clean. 2. Preparation of repair slurry: Add 40% SiC@C powder (by volume), 1% polyvinyl alcohol binder (by mass), and 1% sodium carboxymethyl cellulose dispersant (by mass) to deionized water, and stir magnetically for 12 hours to form a uniform repair slurry. 3. Introducing coating powder: The repair slurry is pressed into the gap area using a pressure impregnation method, and then dried in an oven at 75 ℃ for 6 h; 4. Laser repair: Apply Si slurry (40% solid content) to the damaged surface to form a coating of about 2 mm thickness. Then, under vacuum (200 Pa), scan and repair are performed using parameters of laser power of 500 W, scanning speed of 200 mm / min, spot diameter of 3 mm, and overlap rate of 50%. 5. Post-treatment: After the repair is completed, allow it to cool naturally to room temperature, then use 800-grit sandpaper to sand the surface of the repaired area to make it smooth.

[0045] Mechanical property verification: The mechanical properties of the specimens before and after repair were tested using the three-point bending method, with a span of 30 mm and a loading rate of 0.5 mm / min. The test results showed that the flexural strength of the unrepaired damaged specimen was only 223 MPa, indicating a significant decrease in strength due to the damage. After repair using the method of this invention, the flexural strength of the specimen was significantly increased to 375 MPa, recovering to 83.4% of that of the unrepaired specimen (450 MPa). This demonstrates that the repair method can effectively compensate for defects, restore the structural load-bearing capacity, and achieve significant repair results.

[0046] Example 3 This embodiment provides a repair process for ceramics and ceramic matrix composites, specifically as follows: 1. Sample pretreatment: The cracked SiC ceramic was plasma cleaned for 30 min and then dried in an oven at 75 ℃ for 8 h to remove surface contaminants and debris. 2. Preparation of repair slurry: Add 60% TiC@C powder (by volume), 1% polyvinyl alcohol binder (by mass), and 1% sodium carboxymethyl cellulose dispersant (by mass) to deionized water, and stir magnetically for 8 hours to form a uniform repair slurry; 3. Introducing coating powder: The repair slurry is impregnated with the cracked substrate using a vacuum pressure impregnation method, and then dried in a 75 ℃ oven for 8 h; 4. Laser repair: A 0.5 mm thick Si-Zr alloy powder layer with a particle size of 50 μm is laid on the damaged surface after impregnation. Then, under argon protection, the laid area is scanned and repaired using parameters of laser power of 300 W, scanning speed of 800 mm / min, spot diameter of 0.5 mm, and overlap rate of 30%. 5. Post-processing: After the laser scanning is completed, allow the area to be repaired to cool naturally to room temperature, and then use 800-grit sandpaper to polish the surface to make it smooth.

[0047] Example 4 This embodiment provides a repair process for ceramics and ceramic matrix composites, specifically as follows: 1. Sample pretreatment: Pretreatment of C samples containing notch damage... f / SiC samples were purged with compressed gas and then dried in an oven at 75 °C for 8 h to remove surface contaminants and debris. 2. Preparation of repair slurry: Add 30% HfB2@C powder (by volume), 1% polyvinyl alcohol binder (by mass), and 1% sodium carboxymethyl cellulose dispersant (by mass) to deionized water, and stir magnetically for 15 hours to form a uniform repair slurry; 3. Introducing coating powder: The repair slurry is impregnated with the substrate containing the notched damage using a vacuum impregnation method, and then dried in a 75 ℃ oven for 8 h; 4. Laser repair: A 2 mm thick Si-Y alloy powder layer with a particle size of 100 μm is laid on the damaged surface after impregnation. Then, under nitrogen protection, the laid area is scanned and repaired using parameters of laser power of 800 W, scanning speed of 100 mm / min, spot diameter of 4 mm, and overlap rate of 80%. 5. Post-processing: After the laser scanning is completed, allow the area to be repaired to cool naturally to room temperature, and then use 800-grit sandpaper to polish the surface to make it smooth.

[0048] In summary, the ceramic and ceramic matrix composite repair method based on core-shell structured powder provided by this invention, through a complete process including pretreatment, slurry preparation, powder coating filling, laser in-situ reaction repair, and post-treatment, is applicable to SiC ceramics, C... f / SiC、SiC f This invention repairs typical damage such as cracks and notches in various material systems including SiC. As demonstrated in the embodiments, this method can stably achieve dense filling and interface strengthening of the damaged area by selecting different core-shell structure powders, impregnation methods, silicon sources, and laser parameters. Mechanical property tests show that the flexural strength of the repaired sample can be significantly improved, recovering to more than 80% of that of the intact sample, effectively compensating for defects and restoring the load-bearing capacity of the component. This invention offers flexible processes, strong controllability, and significant repair effects, meeting the needs for efficient, reliable, and in-situ repair of high-temperature structural ceramic components in engineering scenarios, and possesses good practicality and application prospects.

[0049] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A method for repairing ceramics and ceramic matrix composites, characterized in that, The repair method specifically includes the following steps: Step S1: Prepare the repair slurry: Add the coated powder to an inorganic solvent to obtain the repair slurry; Step S2, Introduce repair slurry: Introduce and fill the damaged area of ​​ceramics and ceramic matrix composites with the repair slurry prepared in step S1; Step S3, Laser Repair: Si powder or Si alloy powder is laid on the surface of the damaged area that has been introduced and filled with repair slurry, and the surface of the damaged area with Si powder or Si alloy powder is laser scanned in a protective atmosphere.

2. The repair method as described in claim 1, characterized in that, The ceramics and ceramic matrix composites are selected from SiC ceramics, C... f / SiC composite materials, SiC f One of the SiC composite materials and their modified ceramic matrix composite materials.

3. The repair method as described in claim 1, characterized in that, In step S1, the coated powder comprises 40-80 mol.% of a core ceramic phase and 20-60 mol.% of C, and the particle size of the coated powder is 2-40 μm. The core ceramic phase is selected from one of SiC, HfC, TiC, ZrB2 and HfB2.

4. The repair method as described in claim 1, characterized in that, In step S1, the solid volume fraction of the repair slurry is 30-60 vol.%. The inorganic solvent is deionized water or anhydrous ethanol, and after the coated powder is added to the inorganic solvent, it is subjected to magnetic stirring for 8-15 hours.

5. The repair method as described in claim 1, characterized in that, In step S2, the repair slurry is introduced by impregnation or brushing, and the impregnation method is selected from vacuum impregnation, pressure impregnation or vacuum pressure impregnation.

6. The repair method as described in claim 1, characterized in that, In step S3, the Si powder or Si alloy powder is laid by dry powder laying or brushing slurry, and the thickness of the laying is 0.5-2 mm, wherein the particle size of the Si powder or Si alloy powder is 5-100 μm. The Si alloy powder is selected from at least one of Si-Y alloy powder, Si-Ti alloy powder, Si-Zr alloy powder, Si-Hf alloy powder, Si-Mo alloy powder, and Si-Al alloy powder.

7. The repair method as described in claim 6, characterized in that, When applying Si powder or Si alloy powder by brushing slurry, the solid volume fraction of the slurry is 30-60 vol.% Si powder or Si alloy powder, and the slurry is stirred or ball-milled for 8-15 hours.

8. The repair method as described in claim 1, characterized in that, In step S3, the protective atmosphere is selected from one of vacuum, argon and nitrogen, and the vacuum degree is <500 Pa.

9. The repair method as described in claim 1, characterized in that, In step S3, the parameters for laser scanning processing are as follows: laser power is 300-800 W, scanning speed is 100-800 mm / min, spot diameter is 0.5-4 mm, and overlap rate is 30-80%.

10. The repair method as described in claim 1, characterized in that, Before step S2, the ceramic and ceramic matrix composite material are pretreated. The pretreatment is selected from one or more of the following: ultrasonic cleaning with anhydrous ethanol, solvent spraying or wiping, compressed gas purging, vacuum suction, soft brush cleaning, hot air drying, plasma cleaning and laser cleaning. After the pretreatment, the ceramic and ceramic matrix composite material are dried. It also includes step S4, post-processing: the ceramic and ceramic matrix composite material that have been laser-scanned are naturally cooled to room temperature, and then the surface is polished.

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