Self-repairing environmental barrier coating and method of making and use thereof

Abstract

The present application belongs to the technical field of coating materials, and particularly relates to a self-repairing environmental barrier coating, a preparation method and application thereof. The self-repairing environmental barrier coating comprises a first coating, a second coating and a third coating. The first coating is a coating comprising Ta2O5. The second coating is a R2Si2O7-MeSi2 composite material coating, wherein R is selected from at least one of Yb, Y, Gd, Lu, Nd and Ta, and Me is selected from at least one of Mo, Ta and Yb. The third coating is PrMgAl 11 O 19 coating; the first coating, the second coating and the third coating are sequentially stacked on a substrate; the thermal expansion coefficient of the first coating, the thermal expansion coefficient of the second coating and the thermal expansion coefficient of the third coating are in a gradient increasing distribution. The self-repairing environmental barrier coating has high bending strength retention rate, high high-low temperature cycle service life and oxidation resistance during high-temperature service.

Description

Technical Field

[0001] This invention belongs to the field of coating materials technology, specifically relating to a self-healing environmental barrier coating, its preparation method, and its application. Background Technology

[0002] Silicon carbide fiber-reinforced silicon carbide ceramic matrix composites (SiC) f SiC possesses advantages such as low density, excellent high-temperature mechanical properties, high melting point, low coefficient of expansion, and excellent thermal shock resistance. As a high-temperature structural material, it can replace nickel-based superalloys in hot-end components of aero-engines, thereby achieving the goals of engine weight reduction and increased thrust-to-weight ratio.

[0003] As hot-end components of aero-engines, ceramic matrix composites are subjected to high temperatures, thermal shock, high-temperature water vapor, and molten corrosion products in actual service environments. These conditions reduce the high-temperature mechanical properties of ceramic matrix composites, accelerating their failure and shortening their service life. To overcome these problems, existing ceramic matrix composites have environmental barrier coatings on their surfaces. These coatings offer advantages such as thermal insulation, resistance to thermal shock, and resistance to high-temperature corrosion, providing excellent thermal protection for ceramic matrix composites in high-temperature corrosive environments and extending their service life. However, the retention rate of flexural strength, high and low temperature cycle life, and oxidation resistance of existing environmental barrier coatings in high-temperature (above 1300℃) water vapor environments still need improvement. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of existing environmental barrier coatings, which still have room for improvement in the retention rate of bending resistance, high and low temperature cycle service life and oxidation resistance of ceramic matrix composites protected by them in high temperature (above 1300℃) water vapor environment. Thus, a self-healing environmental barrier coating, its preparation method and application are provided.

[0005] This invention provides a self-healing environmental barrier coating, comprising a first coating, a second coating, and a third coating. The first coating is a coating containing Ta₂O₅, the second coating is an R₂Si₂O₇-MeSi₂ composite material coating, wherein R is selected from at least one of Yb, Y, Gd, Lu, Nd, and Ta, and Me is selected from at least one of Mo, Ta, and Yb. The third coating is PrMgAl. 11 O 19 coating;

[0006] The first coating, the second coating, and the third coating are sequentially stacked on the substrate;

[0007] The coefficients of thermal expansion of the first coating, the second coating, and the third coating show a gradient increasing distribution.

[0008] Preferably, the thickness ratio of the first coating, the second coating, and the third coating is (100-150):(100-200):(100-200);

[0009] And / or, the mass ratio of R2Si2O7 to MeSi2 in the second coating is (80-90):(10-20);

[0010] And / or, the coefficient of thermal expansion of the first coating at 1000°C is 1.5 × 10⁻⁶. -6 -5×10 -6 ℃ -1 The coefficient of thermal expansion of the second coating at 1000℃ is 4×10⁻⁶. -6 -7×10 -6 ℃ -1 The coefficient of thermal expansion of the third coating at 1000℃ is 7×10⁻⁶. -6 -10×10 -6 ℃ -1 ;

[0011] Optionally, the coefficient of thermal expansion of the first coating at 1000°C is 1.5 × 10⁻⁶. -6 -4×10 -6 ℃ -1 The coefficient of thermal expansion of the second coating at 1000℃ is 4×10⁻⁶. -6 -7×10 -6 ℃ -1 The coefficient of thermal expansion of the third coating at 1000℃ is 7×10⁻⁶. -6 -10×10 -6 ℃ -1 ;

[0012] This invention does not limit the matrix; it can be a ceramic matrix, including but not limited to silicon carbide ceramic matrices or silicon carbide ceramic matrix composite matrices. The silicon carbide ceramic matrix composite matrix can be a silicon carbide fiber-reinforced silicon carbide ceramic matrix composite (SiC). f The matrix is ​​SiC. Silicon carbide fiber-reinforced silicon carbide ceramic matrix composite (SiC / SiC composite) refers to a composite material in which SiC fibers are introduced into a SiC ceramic matrix as a reinforcing phase, thereby forming a composite material with SiC fibers as the reinforcing and dispersed phase, and SiC ceramic as the matrix and continuous phase. Optionally, the silicon carbide fibers account for 30-70% of the total mass of the composite material. This invention does not specifically limit the thickness of the matrix.

[0013] This invention provides a method for preparing the above-described self-healing environmental barrier coating, comprising the following steps:

[0014] 1) Mix and grind Ta2O5, the first binder, the first surfactant and water, and dry to obtain the first spray powder. Spray the first spray powder onto the substrate surface using an atmospheric plasma spraying method to form the first coating.

[0015] 2) Mix and grind R2Si2O7 powder, MeSi2, second binder, second surfactant and water, dry to obtain second spray powder, and spray the second spray powder onto the surface of the first coating in step 1) using atmospheric plasma spraying method to form the second coating.

[0016] 3) PrMgAl 11 O 19 The powder, third binder, third surfactant and water are mixed and ground, and dried to obtain third spray powder. The third spray powder is sprayed onto the surface of the second coating described in step 2) using an atmospheric plasma spraying method to form the third coating and obtain the self-healing environmental barrier coating.

[0017] Preferably, in step 1), the first adhesive is selected from at least one of gum arabic and polyvinyl alcohol;

[0018] And / or, the first surfactant is selected from ammonium citrate;

[0019] And / or, the mass of the first binder accounts for 1wt%-3wt% of the total mass of Ta2O5, the first binder, the first surfactant and water;

[0020] And / or, the mass of the first surfactant accounts for 0.5wt%-2wt% of the total mass of Ta2O5, the first binder, the first surfactant and water;

[0021] And / or, the mass of the Ta2O5 accounts for 10-50 wt% of the total mass of Ta2O5, the first binder, the first surfactant and water;

[0022] And / or, the grinding speed in step 1) is 200-500 rpm and the grinding time is 70-74 h;

[0023] Optionally, the grinding in step 1) is performed using ball milling;

[0024] And / or, the drying described in step 1) is performed by spray drying;

[0025] Optionally, the process parameters for spray drying include: inlet air temperature of 210-220℃, outlet air temperature of 115-130℃, and atomizer operating frequency of 25-32Hz.

[0026] Optionally, after drying in step 1), a sieving step is also included, and the particle size of the first spray powder obtained after sieving is 32-125 μm.

[0027] The process parameters of the atmospheric plasma spraying method described in step 1) include: argon flow rate of 30-35 NLPM, hydrogen flow rate of 10-15 NLPM, spray gun power of 40-45 KW, spraying distance between the spray gun and the substrate surface to be sprayed of 100-150 mm, horizontal moving speed of the spray gun of 800-1000 mm / s, pre-cooling gas flow rate of 2-6 bar, and powder feeding rate of 6-15%.

[0028] Optionally, the front cooling air is selected from air; or, optionally, the front cooling air is selected from compressed air.

[0029] And / or, the thickness of the first coating is 100-150 μm;

[0030] Optionally, when using atmospheric plasma spraying to apply the first powder coating, the substrate preheating temperature is 300-500℃.

[0031] Preferably, the preparation method of R2Si2O7 powder in step 2) includes: mixing and grinding metal oxides R2O3 and SiO2 in a molar ratio of 1:(1.9-2.5), drying, and calcining to obtain R2Si2O7 powder;

[0032] Optionally, the grinding speed is 200-500 rpm and the grinding time is 30-48 h;

[0033] Optionally, the grinding is performed using ball milling, with water added during the ball milling process for wet ball milling;

[0034] Optionally, the drying is performed using spray drying;

[0035] The calcination temperature is 1450-1550℃, and the calcination time is 10-20h.

[0036] Preferably, in step 2), the second adhesive is selected from at least one of gum arabic and polyvinyl alcohol;

[0037] And / or, the second surfactant is selected from ammonium citrate;

[0038] And / or, the mass of the second binder accounts for 1-3 wt% of the total mass of R2Si2O7 powder, MeSi2, the second binder, the second surfactant and water;

[0039] And / or, the mass of the second surfactant accounts for 0.5-2 wt% of the total mass of R2Si2O7 powder, MeSi2, the second binder, the second surfactant, and water;

[0040] And / or, the mass of the R2Si2O7 accounts for 2-5 wt% of the total mass of the R2Si2O7 powder, MeSi2, the second binder, the second surfactant, and water;

[0041] And / or, the grinding speed in step 2) is 200-500 rpm, and the grinding time is 60-72 h;

[0042] Optionally, the grinding in step 2) is performed using ball milling;

[0043] And / or, the drying described in step 2) is performed using spray drying;

[0044] Optionally, the process parameters for spray drying include: inlet air temperature of 210-220℃, outlet air temperature of 115-130℃, and atomizer operating frequency of 25-32Hz.

[0045] Optionally, after drying, a sieving step is also included, and the particle size of the second spray powder obtained after sieving is 32-125μm.

[0046] Preferably, the process parameters of the atmospheric plasma spraying method in step 2) include: argon flow rate of 30-35 NLPM, hydrogen flow rate of 10-15 NLPM, spray gun power of 30-40 KW, spraying distance between the spray gun and the surface of the first coating layer of 80-120 mm, horizontal moving speed of the spray gun of 800-1000 mm / s, pre-cooling gas flow rate of 2-6 bar, and powder feeding rate of 10-20%.

[0047] Optionally, the front cooling air is selected from air; or, optionally, the front cooling air is selected from compressed air.

[0048] And / or, the thickness of the second coating is 100-200 μm;

[0049] Optionally, when using atmospheric plasma spraying to apply the second powder coating, the preheating temperature of the substrate and the first coating is 400-700℃.

[0050] Preferably, in step 3), PrMgAl 11 O 19 The powder preparation method includes: Pr6O 11 MgO and Al2O3 powders were mixed, ground, dried, and calcined in a mass ratio of (20-22.3):(5-8):(70-75) to obtain PrMgAl 11 O 19 powder;

[0051] Optionally, the grinding speed is 300-600 rpm and the grinding time is 30-48 h;

[0052] Optionally, the grinding is performed using ball milling, with water added during the ball milling process for wet grinding;

[0053] Optionally, the ball milling is performed using ZrO2 zirconium beads;

[0054] Optionally, the drying is performed using spray drying;

[0055] The roasting temperature is 1400-1600℃, and the roasting time is 24-48h.

[0056] Preferably, the third adhesive in step 3) is selected from at least one of gum arabic and polyvinyl alcohol;

[0057] And / or, the third surfactant is selected from ammonium citrate;

[0058] And / or, the mass of the third binder accounts for a percentage of PrMgAl 11 O 19 1-3 wt% of the total mass of powder, third binder, third surfactant and water;

[0059] And / or, the mass percentage of the third surfactant in PrMgAl 11 O 19 0.5-2 wt% of the total mass of powder, third binder, third surfactant and water;

[0060] And / or, the PrMgAl 11 O 19 The mass percentage of PrMgAl 11 O 19 20-50 wt% of the total mass of powder, third binder, third surfactant and water;

[0061] And / or, the grinding speed in step 3) is 300-600 rpm, and the grinding time is 60-70 h;

[0062] Optionally, the grinding in step 3) is performed using ball milling;

[0063] And / or, the drying described in step 3) is performed using spray drying;

[0064] Optionally, the process parameters for spray drying include: inlet air temperature of 210-220℃, outlet air temperature of 115-130℃, and atomizer operating frequency of 25-32Hz.

[0065] Optionally, after drying in step 3), a sieving step is also included, and the particle size of the third spray powder obtained after sieving is 32-125 μm.

[0066] The process parameters of the atmospheric plasma spraying method described in step 3) include: argon flow rate of 30-35 NLPM, hydrogen flow rate of 10-15 NLPM, spray gun power of 30-40 KW, spraying distance between the spray gun and the second spraying surface of 80-120 mm, horizontal moving speed of the spray gun of 800-1000 mm / s, pre-cooling gas flow rate of 2-6 bar, and powder feeding rate of 10-20%.

[0067] Optionally, the front cooling air is selected from air; or, optionally, the front cooling air is selected from compressed air.

[0068] And / or, the thickness of the third coating is 100-200 μm;

[0069] Optionally, when using atmospheric plasma spraying to apply the third powder coating, the preheating temperature of the substrate, the first coating, and the second coating is 300-500℃.

[0070] This invention provides an application of the self-healing environmental barrier coating described above or the self-healing environmental barrier coating prepared by the above preparation method in aero-engine component materials.

[0071] The technical solution of this invention has the following advantages:

[0072] The self-healing environmental barrier coating provided by this invention comprises a first coating, a second coating, and a third coating. The first coating is a coating containing Ta₂O₅, the second coating is an R₂Si₂O₇-MeSi₂ composite material coating, wherein R is selected from at least one of Yb, Y, Gd, Lu, Nd, and Ta, and Me is selected from at least one of Mo, Ta, and Yb. The third coating is PrMgAl. 11 O 19 The coating consists of three layers: a first layer, a second layer, and a third layer, sequentially stacked on a substrate. The coefficients of thermal expansion of the first, second, and third layers increase in a gradient. The first layer of the self-healing environmental barrier coating of this invention comprises Ta₂O₅, which has a low coefficient of thermal expansion and a high melting point, serving as a binder layer to enable the coating to operate at 1500°C, thereby improving its service temperature and lifespan. The R₂Si₂O₇-MeSi₂ coating on the surface of the first layer acts as a self-healing coating. Utilizing the volume expansion of the MeSi₂ self-healing medium during oxidation, cracks generated during service self-heal, improving the coating's oxidation resistance and service life. The R₂Si₂O₇-MeSi₂ coating surface also contains PrMgAl, which has high infrared radiation. 11 O 19A coating is applied to reduce the surface temperature of the coating and increase its service temperature. The first coating (containing Ta₂O₅) provides good adhesion between the overall coating and the substrate, while further inhibiting the diffusion of oxidizing media into the substrate. High infrared radiation PrMgAl 11 O 19 The coating can lower the surface temperature of the coating layer, reducing heat transfer to the underlying R2Si2O7-MeSi2 coating and the first coating containing Ta2O5. Furthermore, PrMgAl 11 O 19 While the coating can prevent the diffusion of oxidizing media to a certain extent, some oxidizing media still diffuse into the coating interior. The R2Si2O7-MeSi2 coating can absorb this diffusion into the coating interior, and the stress generated during the MeSi2 oxidation process can offset the release of thermal mismatch stress in the coating, effectively inhibiting crack formation. During high-temperature service, the first coating containing Ta2O5 reacts in situ with the R2Si2O7-MeSi2 coating to form a dense tantalate layer, further improving the coating's oxidation resistance. Simultaneously, compared with existing coating systems, the gradient-designed environmental barrier coating is beneficial in reducing thermal mismatch stress and mitigating crack formation during high-temperature service, achieving a coating that integrates high service temperature, oxidation resistance, corrosion resistance, and high infrared emission structural functions, thereby improving the coating's service life. The self-healing environmental barrier coating of this invention, with its specific first, second, and third coatings working synergistically, still exhibits high flexural strength retention, high high and low temperature cycle life, and oxidation resistance during high-temperature service. Attached Figure Description

[0073] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0074] Figure 1 The structural diagram of the self-healing environmental barrier coating prepared in Example 1 of this invention on the substrate;

[0075] Reference numerals: 1-substrate, 2-first coating, 3-second coating, 4-third coating. Detailed Implementation

[0076] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0077] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0078] The matrix used in the embodiments and comparative examples of this invention is: silicon carbide fiber-toughened silicon carbide ceramic matrix composite material (SiC). f The silicon carbide fiber-reinforced silicon carbide ceramic matrix composite material (SiC composite material) comprises a matrix of silicon carbide fibers, which account for 45% of the total mass of the silicon carbide fiber-reinforced silicon carbide ceramic matrix composite material. The silicon carbide fiber-reinforced silicon carbide ceramic matrix composite material (SiC composite material) used in the embodiments and comparative examples of this invention... f The SiC composite matrix undergoes pretreatment before use, including: roughening the matrix surface with 150-mesh silicon carbide sand to achieve a surface roughness of 10 μm, followed by ultrasonic cleaning. Then, the circular matrix is ​​polished using a diamond grinding disc to round off its edges, followed by ultrasonic cleaning and drying. Next, it is heat-treated at 550℃ for 3 hours to remove impurities and reduce stress. Finally, it is soaked in alcohol for 6 hours and dried at 80℃. The matrix thickness is 20 mm.

[0079] Example 1

[0080] This embodiment provides a method for preparing a self-healing environmental barrier coating, including the following steps:

[0081] 1) Mix Ta₂O₅, gum arabic, ammonium citrate, and deionized water and ball mill at 400 rpm for 72 h. The mass percentage of Ta₂O₅ is 25 wt%, gum arabic is 2 wt%, and ammonium citrate is 0.8 wt%. Prepare a free-flowing powder for spraying using a spray granulation method (spray drying process parameters include: inlet air temperature 215℃, outlet air temperature 125℃, atomizer operating frequency 30 Hz). Use a vibrating sieve separator to granulate the powder. The powder was sieved to select particles with a diameter of 32-125 μm as the first coating powder. The substrate was preheated to 500℃, and then the first coating powder was sprayed onto the substrate surface using an atmospheric plasma spraying method to form a first coating. The process parameters for the atmospheric plasma spraying method included: argon flow rate of 32 NLPM, hydrogen flow rate of 12 NLPM, spray gun power of 45 kW, spraying distance between the spray gun and the substrate surface of 130 mm, horizontal moving speed of the spray gun of 900 mm / s, pre-cooling gas (air) flow rate of 5 bar, and powder feed rate of 10%. The thickness of the first coating was 120 μm. The coefficient of thermal expansion of the first coating at 1000℃ was 3.8 × 10⁻⁶. -6 ℃ -1 ;

[0082] 2) Weigh Yb₂O₃ and SiO₂ at a molar ratio of 1:2, add appropriate amounts of deionized water and zirconia ball milling media to prepare a slurry, place it in a ball mill jar, and ball mill at 400 rpm for 40 h. Then, dry the mixed slurry by spray drying to obtain a mixed powder. Then, place the mixed powder in a crucible, place the crucible in a muffle furnace at 1550℃, and keep it at that temperature for 15 h to synthesize Yb₂Si₂O₇ powder through a solid-state reaction. Then, combine the Yb₂Si₂O₇ powder, MoSi₂, gum arabic, ammonium citrate, and... The mixture of deionized water and zirconia ball milling media was placed in a milling jar and ground at 400 rpm for 65 h. The mass of Yb₂Si₂O₇ powder accounted for 2 wt% of the total mass of Yb₂Si₂O₇ powder, MoSi₂, gum arabic, ammonium citrate, and deionized water. The mass ratio of Yb₂Si₂O₇ to MoSi₂ was 90:10. The mass of gum arabic accounted for 2.5 wt% of the total mass of Yb₂Si₂O₇ powder, MoSi₂, gum arabic, ammonium citrate, and deionized water. The mass of ammonium citrate accounted for a certain percentage of the total mass of Yb₂Si₂O₇ powder, MoSi₂, gum arabic, ammonium citrate, and deionized water. The total mass of O2O7 powder, MoSi2, gum arabic, ammonium citrate, and deionized water was 1.2 wt%. A free-flowing spray powder was then prepared using a spray granulation method (the spray drying process parameters included: inlet air temperature of 215℃, outlet air temperature of 125℃, and atomizer operating frequency of 30Hz). The powder was sieved using a vibrating sieve, and powder with a particle size of 32-125 μm was selected as the second spray powder. The first coating and substrate were then preheated to 500℃, and then atmospheric plasma spraying was performed. The second coating powder is sprayed onto the surface of the first coating to form the second coating. The process parameters for the atmospheric plasma spraying method include: argon flow rate of 32 NLPM, hydrogen flow rate of 12 NLPM, spray gun power of 35 kW, spray gun distance from the substrate surface of 90 mm, horizontal spray gun speed of 900 mm / s, pre-cooling gas (air) flow rate of 5 bar, and powder feed rate of 15%. The second coating thickness is 150 μm. The coefficient of thermal expansion of the second coating at 1000℃ is 4.9 × 10⁻⁶. -6 ℃ -1 ;

[0083] 3) The rare earth oxide Pr6O 11 MgO and Al2O3 powders were weighed at a mass ratio of 22.1:5.2:72.7, and a slurry was prepared using deionized water as a solvent. This slurry was then mixed with ZrO2 zirconium beads and placed in a ball mill jar. The mixture was ball-milled at 500 rpm for 40 hours. The slurry was then spray-dried to obtain a mixed powder. The mixed powder was placed in a crucible and kept in a muffle furnace at 1600℃ for 30 hours. Through a high-temperature solid-state reaction, rare earth hexaaluminate PrMgAl was obtained. 11 O 19 Powder, then PrMgAl 11 O19 A mixture of powder, gum arabic, ammonium citrate, and deionized water, wherein PrMgAl 11 O 19 The mass percentage of PrMgAl 11 O 19 The powder, gum arabic, ammonium citrate, and deionized water comprise 25 wt% of the total mass of PrMgAl. 11 O 19 The total mass of powder, gum arabic, ammonium citrate, and deionized water was 2.6 wt%, and the mass of ammonium citrate accounted for 2.6 wt% of PrMgAl. 11 O 19 1.5 wt% of the total mass of powder, gum arabic, ammonium citrate, and deionized water was placed in a ball mill jar and ball-milled at 500 rpm for 65 h. Then, it was spray-granulated to obtain a spray-coating powder with good flowability (the spray drying process parameters included: inlet air temperature of 215℃, outlet air temperature of 120℃, and atomizer operating frequency of 30 Hz). The powder was sieved using a vibrating sieve to select a third spray powder with a particle size of 32-125 μm. The second coating, first coating, and substrate were preheated to 500℃, and then atmospheric plasma was used. The spraying method involves spraying a third coating powder onto the surface of the second coating layer to form a third coating. The process parameters for the atmospheric plasma spraying method include: argon flow rate of 32 NLPM, hydrogen flow rate of 12 NLPM, spray gun power of 35 kW, spray gun distance from the substrate surface of 100 mm, horizontal spray gun movement speed of 900 mm / s, pre-cooling gas (air) flow rate of 5 bar, and powder feed rate of 15%. The thickness of the third coating is 150 μm. The coefficient of thermal expansion of the third coating at 1000℃ is 8.5 × 10⁻⁶. -6 ℃ -1 The self-healing environmental barrier coating is obtained, and its structural schematic diagram is shown below. Figure 1 As shown, it includes a substrate 1, a first coating 2, a second coating 3, and a third coating 4.

[0084] Example 2

[0085] This embodiment provides a method for preparing a self-healing environmental barrier coating, including the following steps:

[0086] 1) Mix Ta₂O₅, gum arabic, ammonium citrate, and deionized water and ball mill at 200 rpm for 74 h. The mass of Ta₂O₅ should be 30 wt% of the total mass of Ta₂O₅, gum arabic, ammonium citrate, and deionized water; the mass of gum arabic should be 3 wt% of the total mass of Ta₂O₅, gum arabic, ammonium citrate, and deionized water; and the mass of ammonium citrate should be 1.5 wt% of the total mass of Ta₂O₅, gum arabic, ammonium citrate, and deionized water. Prepare a free-flowing powder for spraying using a spray granulation method (spray drying process parameters include: inlet air temperature 220℃, outlet air temperature 130℃, and atomizer operating frequency 32Hz). Use a vibrating sieve separator to sift the powder. The powder was sieved to select particles with a diameter of 32-125 μm as the first coating powder. The substrate was preheated to 400℃, and then the first coating powder was sprayed onto the substrate surface using an atmospheric plasma spraying method to form a first coating. The process parameters for the atmospheric plasma spraying method included: argon flow rate of 30 NLPM, hydrogen flow rate of 10 NLPM, spray gun power of 40 kW, spraying distance between the spray gun and the substrate surface of 100 mm, horizontal moving speed of the spray gun of 800 mm / s, pre-cooling gas (air) flow rate of 2 bar, and powder feed rate of 6%. The thickness of the first coating was 150 μm. The coefficient of thermal expansion of the first coating at 1000℃ was 3.8 × 10⁻⁶. -6 ℃ -1 ;

[0087] 2) Weigh Y₂O₃ and SiO₂ at a molar ratio of 1:2, add appropriate amounts of deionized water and zirconia ball milling media to prepare a slurry, place it in a ball mill jar, and ball mill at 200 rpm for 48 h. Then, dry the mixed slurry by spray drying to obtain a mixed powder. Then, place the mixed powder in a crucible, place the crucible in a muffle furnace at 1500℃, and keep it at that temperature for 20 h to synthesize Y₂Si₂O₇ powder through a solid-state reaction. Then, combine the Y₂Si₂O₇ powder, TaSi₂, gum arabic, ammonium citrate, and deionized water... The mixture of Y₂Si₂O₇ powder and zirconia ball milling media was placed in a milling jar and ground at 200 rpm for 70 h. The mass of Y₂Si₂O₇ powder accounted for 6 wt% of the total mass of Y₂Si₂O₇ powder, TaSi₂, gum arabic, ammonium citrate, and deionized water. The mass ratio of Y₂Si₂O₇ to TaSi₂ was 85:15. The mass of gum arabic accounted for 3 wt% of the total mass of Y₂Si₂O₇ powder, TaSi₂, gum arabic, ammonium citrate, and deionized water. The mass of ammonium citrate accounted for a certain percentage of the total mass of Y₂Si₂O₇ powder. The total mass of TaSi2, gum arabic, ammonium citrate, and deionized water is 1.5 wt%. A free-flowing spray powder is then prepared using a spray granulation method (spray drying process parameters include: inlet air temperature of 210℃, outlet air temperature of 115℃, and atomizer operating frequency of 25Hz). The powder is sieved using a vibrating sieve, and powder with a particle size of 32-125 μm is selected as the second spray powder. The first coating and substrate are then preheated to 400℃, and the second spray powder is applied using an atmospheric plasma spraying method. Powder is sprayed onto the surface of the first coating layer to form a second coating layer. The process parameters for the atmospheric plasma spraying method include: argon flow rate of 35 NLPM, hydrogen flow rate of 13 NLPM, spray gun power of 40 kW, spray gun distance from the substrate surface of 120 mm, horizontal spray gun speed of 1000 mm / s, pre-cooling air flow rate of 4 bar, and powder feed rate of 10%. The second coating layer thickness is 200 μm. The coefficient of thermal expansion of the second coating layer at 1000℃ is 5.5 × 10⁻⁶. -6 ℃ -1 ;

[0088] 3) The rare earth oxide Pr6O 11 MgO and Al2O3 powders were weighed at a mass ratio of 22.1:5.2:72.7, and a slurry was prepared using deionized water as a solvent. This slurry was then mixed with ZrO2 zirconium beads and placed in a ball mill jar. The mixture was ball-milled at 500 rpm for 48 hours. The slurry was then spray-dried to obtain a mixed powder. The mixed powder was placed in a crucible and kept at 1400℃ in a muffle furnace for 48 hours. Through a high-temperature solid-state reaction, rare earth hexaaluminate PrMgAl was obtained. 11 O 19 Powder, then PrMgAl 11 O 19A mixture of powder, gum arabic, ammonium citrate, and deionized water, wherein PrMgAl 11 O 19 The mass percentage of PrMgAl 11 O 19 The total mass of powder, gum arabic, ammonium citrate, and deionized water is 30 wt%, and the mass of gum arabic accounts for 30% of the total mass of PrMgAl. 11 O 19 The total mass of powder, gum arabic, ammonium citrate, and deionized water is 1 wt%, and the mass of ammonium citrate accounts for 1 wt% of PrMgAl. 11 O 19 0.5 wt% of the total mass of powder, gum arabic, ammonium citrate, and deionized water was placed in a ball mill jar and ball-milled at 300 rpm for 60 h. Then, it was spray-granulated to obtain a spray-coating powder with good flowability (the spray drying process parameters included: inlet air temperature of 220℃, outlet air temperature of 115℃, and atomizer operating frequency of 25 Hz). The powder was sieved using a vibrating sieve to select a third spray powder with a particle size of 32-125 μm. The second coating, first coating, and substrate were preheated to 400℃, and then atmospheric plasma was used. The spraying method involves spraying a third coating powder onto the surface of the second coating layer to form a third coating. The process parameters for the atmospheric plasma spraying method include: argon flow rate of 32 NLPM, hydrogen flow rate of 12 NLPM, spray gun power of 35 kW, spraying distance between the spray gun and the substrate surface of 100 mm, horizontal movement speed of the spray gun of 1000 mm / s, pre-cooling gas (air) flow rate of 5 bar, and powder feed rate of 20%. The thickness of the third coating is 200 μm. The coefficient of thermal expansion of the third coating at 1000℃ is 8.5 × 10⁻⁶. -6 ℃ -1 The self-healing environmental barrier coating is obtained.

[0089] Example 3

[0090] This embodiment provides a method for preparing a self-healing environmental barrier coating, including the following steps:

[0091] 1) Mix Ta2O5, gum arabic, ammonium citrate, and deionized water and ball mill at 200 rpm for 74 h. The mass of Ta2O5 should be 40 wt% of the total mass of Ta2O5, gum arabic, ammonium citrate, and deionized water; the mass of gum arabic should be 1 wt% of the total mass of Ta2O5, gum arabic, ammonium citrate, and deionized water; and the mass of ammonium citrate should be 1 wt% of the total mass of Ta2O5, gum arabic, ammonium citrate, and deionized water. Prepare a free-flowing powder for spraying using a spray granulation method (spray drying process parameters include: inlet air temperature of 210℃, outlet air temperature of 115℃, and atomizer operating frequency of 25 Hz). Sift the powder using a vibrating sieve. Powder with a particle size of 32-125 μm was selected as the first coating powder. The substrate was preheated to 500℃, and then the first coating powder was sprayed onto the substrate surface using an atmospheric plasma spraying method to form a first coating. The process parameters of the atmospheric plasma spraying method included: argon flow rate of 35 NLPM, hydrogen flow rate of 15 NLPM, spray gun power of 42 kW, spraying distance between the spray gun and the substrate surface of 150 mm, horizontal moving speed of the spray gun of 1000 mm / s, pre-cooling gas (air) flow rate of 6 bar, and powder feed rate of 15%. The thickness of the first coating was 100 μm. The coefficient of thermal expansion of the first coating at 1000℃ was 3.8 × 10⁻⁶. -6 ℃ -1 ;

[0092] 2) Weigh rare earth oxides Lu₂O₃R₂O₃ (where R represents rare earth elements such as Yb, Y, Gd, Lu, Nd, and Ta) and SiO₂ at a molar ratio of 1:2, add appropriate amounts of deionized water and zirconium oxide ball milling media, prepare a slurry, place it in a ball mill jar, and ball mill at 500 rpm for 30 hours. Then, dry the mixed slurry by spray drying to obtain a mixed powder. Next, place the mixed powder in a crucible, place the crucible in a muffle furnace at 1450℃, and hold for 20 hours to synthesize Lu₂Si₂O₇ powder through a solid-state reaction. Lu₂Si₂O₇ powder, YbSi₂, gum arabic, ammonium citrate, and deionized water were mixed and ground in a ball mill jar at 200 rpm for 60 h using zirconia ball milling media. The mass of Lu₂Si₂O₇ powder accounted for 5 wt% of the total mass of Lu₂Si₂O₇ powder, YbSi₂, gum arabic, ammonium citrate, and deionized water. The mass ratio of Lu₂Si₂O₇ to YbSi₂ was 80:20, and the mass of gum arabic accounted for [amount missing]% of the total mass of Lu₂Si₂O₇ powder, YbSi₂, gum arabic, ammonium citrate, and deionized water. 3 wt% of ammonium citrate was added, and 2 wt% of the total mass of Lu2Si2O7 powder, YbSi2, gum arabic, ammonium citrate, and deionized water was added. Then, a free-flowing spray powder was prepared using a spray granulation method (the spray drying process parameters included: inlet air temperature of 210℃, outlet air temperature of 120℃, and atomizer operating frequency of 25Hz). The powder was sieved using a vibrating sieve, and powder with a particle size of 32-125μm was selected as the second spray powder. The first coating and substrate were then preheated to 500℃, and then a large... The atmospheric plasma spraying method involves spraying a second coating powder onto the surface of the first coating to form a second coating. The process parameters for this method include: argon flow rate of 30 NLPM, hydrogen flow rate of 10 NLPM, spray gun power of 30 kW, spray gun distance from the substrate surface of 80 mm, horizontal spray gun speed of 800 mm / s, pre-cooling gas (air) flow rate of 6 bar, and powder feed rate of 20%. The second coating thickness is 100 μm, and the coefficient of thermal expansion of the second coating at 1000℃ is 5.2 × 10⁻⁶. -6 ℃ -1 ;

[0093] 3) The rare earth oxide Pr6O 11 MgO and Al2O3 powders were weighed at a mass ratio of 22.1:5.2:72.7, and a slurry was prepared using deionized water as a solvent. This slurry was then mixed with ZrO2 zirconium beads and placed in a ball mill jar. The mixture was ball-milled at 300 rpm for 30 hours. The slurry was then spray-dried to obtain a mixed powder. The mixed powder was placed in a crucible and kept in a muffle furnace at 1400℃ for 24 hours. Through a high-temperature solid-state reaction, rare earth hexaaluminate PrMgAl was obtained. 11 O 19Powder, then PrMgAl 11 O 19 A mixture of powder, gum arabic, ammonium citrate, and deionized water, wherein PrMgAl 11 O 19 The mass percentage of PrMgAl 11 O 19 The total mass of powder, gum arabic, ammonium citrate, and deionized water is 40 wt%, and the mass of gum arabic accounts for 40% of the total mass of PrMgAl. 11 O 19 The total mass of powder, gum arabic, ammonium citrate, and deionized water was 2.2 wt%, and the mass of ammonium citrate accounted for 2.2 wt% of PrMgAl. 11 O 19 1 wt% of the total mass of powder, gum arabic, ammonium citrate, and deionized water was placed in a ball mill jar and ball-milled at 300 rpm for 60 h. Then, it was spray-granulated to obtain a spray-coating powder with good flowability (the spray drying process parameters included: inlet air temperature of 220℃, outlet air temperature of 115℃, and atomizer operating frequency of 32 Hz). The powder was sieved using a vibrating sieve to select a third spray powder with a particle size of 32-125 μm. The second coating, first coating, and substrate were preheated to 500℃, and then atmospheric plasma was used. The spraying method involves spraying a third coating powder onto the surface of the second coating layer to form a third coating. The process parameters for the atmospheric plasma spraying method include: argon flow rate of 35 NLPM, hydrogen flow rate of 15 NLPM, spray gun power of 30 kW, spray gun distance from the substrate surface of 80 mm, horizontal spray gun movement speed of 800 mm / s, pre-cooling gas (air) flow rate of 6 bar, and powder feed rate of 20%. The thickness of the third coating is 100 μm. The coefficient of thermal expansion of the third coating at 1000℃ is 8.5 × 10⁻⁶. -6 ℃ -1 The self-healing environmental barrier coating is obtained.

[0094] Comparative Example 1

[0095] This comparative example provides a method for preparing an environmental barrier coating, which differs from Example 1 only in that a first coating is not prepared, and a second spray powder is directly sprayed onto the substrate surface to form a second coating.

[0096] Comparative Example 2

[0097] This comparative example provides a method for preparing an environmental barrier coating, which differs from Example 1 only in that a second coating is not prepared, and a third spray powder is directly sprayed onto the surface of the first coating to form a third coating.

[0098] Comparative Example 3

[0099] This comparative example provides a method for preparing an environmental barrier coating, which differs from Example 1 only in that a third coating is not prepared, and the environmental barrier coating is obtained by spraying the second spray powder onto the surface of the first coating.

[0100] Comparative Example 4

[0101] This comparative example provides a method for preparing an environmental barrier coating, which differs from Example 1 only in that Ta2O5 in step 1) is replaced with an equal mass of Si.

[0102] Test case

[0103] During actual service, aero-engines often produce 8-10 vol.% water vapor in their combustion flames. This invention simulates the high-temperature water vapor environment during aero-engine operation using high-temperature water-oxygen corrosion. The simulation conditions are as follows: the environmental barrier coatings (with a substrate beneath the environmental barrier coatings) obtained in Examples 1-3 and Comparative Examples 1-4 are placed above corundum crucibles and transported to the center of a tube furnace. The tube furnace is heated to 1400°C at a heating rate of 5°C / min. Throughout the heating process, oxygen is continuously introduced into the tube furnace at a flow rate of 200 ml / min and a pressure of 0.1 MPa. When the tube furnace reaches 1400°C, the oxygen flow rate is adjusted to maintain 1 ml / min, and water vapor is simultaneously introduced. The volume ratio of steam to oxygen was 90:10, and the high-temperature water-oxygen corrosion simulation experiment was completed under these conditions for 300 hours. The three-point bending strength of the samples obtained in Examples 1-3 and Comparative Examples 1-4 was tested before and after the water-oxygen corrosion simulation experiment at room temperature. The retention rate of the three-point bending strength of the samples obtained in Examples 1-3 and Comparative Examples 1-4 after the water-oxygen corrosion simulation experiment was calculated (Retention rate of three-point bending strength after water-oxygen corrosion simulation experiment = (Three-point bending strength at room temperature after water-oxygen corrosion simulation experiment / Three-point bending strength at room temperature before water-oxygen corrosion simulation experiment) * 100%). The results are shown in Table 1. The three-point bending strength was tested according to the national standard GBT6569-2006, and three parallel samples were tested for each example or comparative example.

[0104] The samples obtained from Examples 1-3 and Comparative Examples 1-4 were first subjected to the high-temperature water-oxygen corrosion simulation experiment described above, and then flame thermal cycling tests were conducted according to the standard GJB 9876-2020. The test temperature on the surface of the environmental barrier coating reached 1500℃, and the maximum number of thermal cycles was 2000. Three parallel samples were tested for each example or comparative example. The flame thermal cycling life results are shown in Table 1. After the flame thermal cycling test, the appearance of the coating was observed to see if there were cracks or peeling, and whether the coating surface remained intact to evaluate its oxidation resistance. The oxidation resistance results are shown in Table 1. The surface temperature of the samples was measured using a KT15.99 infrared thermometer manufactured by Heitronics, Germany.

[0105] Table 1

[0106]

[0107] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A self-healing environmental barrier coating, characterized in that, The self-healing environmental barrier coating comprises a first coating, a second coating, and a third coating. The first coating is a coating containing Ta2O5. The second coating is an R2Si2O7-MeSi2 composite material coating, wherein R is selected from at least one of Yb, Y, Gd, Lu, Nd, and Ta, and Me is selected from at least one of Mo, Ta, and Yb. The third coating is PrMgAl. 11 O 19 coating; The first coating, the second coating, and the third coating are sequentially stacked on the substrate; The coefficients of thermal expansion of the first coating, the second coating, and the third coating show a gradient increasing distribution.

2. The self-healing environmental barrier coating according to claim 1, characterized in that, The thickness ratio of the first coating, the second coating, and the third coating is (100-150):(100-200):(100-200). And / or, the mass ratio of R2Si2O7 to MeSi2 in the second coating is (80-90):(10-20); And / or, the coefficient of thermal expansion of the first coating at 1000°C is 1.5 × 10⁻⁶. -6 -5 × 10 -6 ℃ -1 The coefficient of thermal expansion of the second coating at 1000℃ is 4 × 10⁻⁶. -6 -7 ×10 -6 ℃ -1 The coefficient of thermal expansion of the third coating at 1000℃ is 7 × 10⁻⁶. -6 -10 ×10 -6 ℃ -1 ; And / or, the matrix includes a silicon carbide ceramic matrix or a silicon carbide ceramic matrix composite matrix.

3. A method for preparing the self-healing environmental barrier coating as described in claim 1 or 2, characterized in that, Includes the following steps: 1) Mix and grind Ta2O5, the first binder, the first surfactant and water, and dry to obtain the first spray powder. Spray the first spray powder onto the substrate surface using an atmospheric plasma spraying method to form the first coating. 2) Mix and grind R2Si2O7 powder, MeSi2, second binder, second surfactant and water, dry to obtain second spray powder, and spray the second spray powder onto the surface of the first coating in step 1) using atmospheric plasma spraying method to form the second coating. 3) PrMgAl 11 O 19 The powder, third binder, third surfactant and water are mixed and ground, and dried to obtain third spray powder. The third spray powder is sprayed onto the surface of the second coating described in step 2) using an atmospheric plasma spraying method to form the third coating and obtain the self-healing environmental barrier coating.

4. The preparation method according to claim 3, characterized in that, In step 1), the first adhesive is selected from at least one of gum arabic and polyvinyl alcohol; And / or, the first surfactant is selected from ammonium citrate; And / or, the mass of the first binder accounts for 1wt%-3wt% of the total mass of Ta2O5, the first binder, the first surfactant, and water; And / or, the mass of the first surfactant accounts for 0.5wt%-2wt% of the total mass of Ta2O5, the first binder, the first surfactant, and water; And / or, the mass of the Ta2O5 accounts for 10-50 wt% of the total mass of Ta2O5, the first binder, the first surfactant, and water; And / or, the grinding speed in step 1) is 200-500 rpm, and the grinding time is 70-74 h; And / or, the process parameters of the atmospheric plasma spraying method described in step 1) include: argon flow rate of 30-35 NLPM, hydrogen flow rate of 10-15 NLPM, spray gun power of 40-45 KW, spraying distance between the spray gun and the substrate surface to be sprayed of 100-150 mm, horizontal moving speed of the spray gun of 800-1000 mm / s, pre-cooling gas flow rate of 2-6 bar, and powder feeding rate of 6-15%; And / or, the thickness of the first coating is 100-150µm; And / or, when using atmospheric plasma spraying to spray the first powder coating, the substrate preheating temperature is 300-500℃; And / or, the drying described in step 1) is performed using spray drying.

5. The preparation method according to claim 4, characterized in that, The process parameters for spray drying include: inlet air temperature of 210-220℃, outlet air temperature of 115-130℃, and atomizer operating frequency of 25-32Hz. And / or, after drying in step 1), a sieving step is also included, and the particle size of the first spray powder obtained after sieving is 32-125 μm.

6. The preparation method according to any one of claims 3-5, characterized in that, The preparation method of R2Si2O7 powder in step 2) includes: mixing and grinding metal oxides R2O3 and SiO2 in a molar ratio of 1:(1.9-2.5), drying, and calcining to obtain R2Si2O7 powder.

7. The preparation method according to claim 6, characterized in that, The grinding speed is 200-500 rpm, and the grinding time is 30-48 h; And / or, the calcination temperature is 1450-1550℃, and the calcination time is 10-20 h.

8. The preparation method according to any one of claims 3-7, characterized in that, In step 2), the second adhesive is selected from at least one of gum arabic and polyvinyl alcohol; And / or, the second surfactant is selected from ammonium citrate; And / or, the mass of the second binder accounts for 1-3 wt% of the total mass of R2Si2O7 powder, MeSi2, the second binder, the second surfactant, and water; And / or, the mass of the second surfactant accounts for 0.5-2 wt% of the total mass of R2Si2O7 powder, MeSi2, the second binder, the second surfactant, and water; And / or, the mass of the R2Si2O7 accounts for 2-5 wt% of the total mass of the R2Si2O7 powder, MeSi2, the second binder, the second surfactant, and water; And / or, the grinding speed in step 2) is 200-500 rpm, and the grinding time is 60-72 h; And / or, the drying described in step 2) is performed by spray drying.

9. The preparation method according to claim 8, characterized in that, The process parameters for spray drying include: inlet air temperature of 210-220℃, outlet air temperature of 115-130℃, and atomizer operating frequency of 25-32Hz. And / or, after drying, a sieving step is also included, and the particle size of the second spray powder obtained after sieving is 32-125μm.

10. The preparation method according to any one of claims 3-9, characterized in that, The process parameters of the atmospheric plasma spraying method described in step 2) include: argon flow rate of 30-35 NLPM, hydrogen flow rate of 10-15 NLPM, spray gun power of 30-40 KW, spraying distance between the spray gun and the surface of the first coating layer of 80-120 mm, horizontal moving speed of the spray gun of 800-1000 mm / s, pre-cooling gas flow rate of 2-6 bar, and powder feeding rate of 10-20%. And / or, the thickness of the second coating is 100-200µm; And / or, when using atmospheric plasma spraying to apply the second powder coating, the preheating temperature of the substrate and the first coating is 400-700℃.

11. The preparation method according to any one of claims 3-10, characterized in that, Step 3) PrMgAl 11 O 19 The powder preparation method includes: Pr6O 11 MgO and Al2O3 powders were mixed, ground, dried, and calcined in a mass ratio of (20-22.3):(5-8):(70-75) to obtain PrMgAl 11 O 19 powder..

12. The preparation method according to claim 11, characterized in that, The grinding speed is 300-600 rpm, and the grinding time is 30-48 h; And / or, the calcination temperature is 1400-1600℃, and the calcination time is 24-48 h.

13. The preparation method according to any one of claims 3-12, characterized in that, The third adhesive mentioned in step 3) is selected from at least one of gum arabic and polyvinyl alcohol; And / or, the third surfactant is selected from ammonium citrate; And / or, the mass of the third binder accounts for a percentage of PrMgAl 11 O 19 1-3 wt% of the total mass of powder, third binder, third surfactant, and water; And / or, the mass percentage of the third surfactant in PrMgAl 11 O 19 0.5-2 wt% of the total mass of powder, third binder, third surfactant, and water; And / or, the PrMgAl 11 O 19 The mass percentage of PrMgAl 11 O 19 20-50 wt% of the total mass of powder, third binder, third surfactant and water; And / or, the grinding speed described in step 3) is 300-600 rpm, and the grinding time is 60-70 h; And / or, the process parameters of the atmospheric plasma spraying method described in step 3) include: argon flow rate of 30-35 NLPM, hydrogen flow rate of 10-15 NLPM, spray gun power of 30-40 KW, spraying distance between the spray gun and the second spraying surface of 80-120 mm, horizontal moving speed of the spray gun of 800-1000 mm / s, pre-cooling gas flow rate of 2-6 bar, and powder feeding rate of 10-20%; And / or, the thickness of the third coating is 100-200µm; And / or, when using atmospheric plasma spraying to spray the third powder coating, the preheating temperature of the substrate, the first coating, and the second coating is 300-500℃; And / or, the drying described in step 3) is performed by spray drying.

14. The preparation method according to claim 13, characterized in that, The process parameters for spray drying include: inlet air temperature of 210-220℃, outlet air temperature of 115-130℃, and atomizer operating frequency of 25-32Hz. And / or, after drying in step 3), a sieving step is also included, and the particle size of the third spray powder obtained after sieving is 32-125μm.

15. The application of the self-healing environmental barrier coating according to claim 1 or 2 or the self-healing environmental barrier coating prepared by the preparation method according to any one of claims 3-14 in aero-engine component materials.

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