Ultrahigh-temperature corrosion-resistant ceramic matrix composite turbine blade

Abstract

The invention discloses an ultrahigh-temperature corrosion-resistant ceramic matrix composite turbine blade, which belongs to the technical field of turbine engines and comprises a blade base body and a gradient corrosion-resistant coating compounded on the surface of the blade base body. The blade base body is made of a ceramic-based composite material and is composed of 25%-40% of a reinforcing phase, 55%-70% of a base body phase and 1%-5% of a Y2O3-La2O3 composite sintering aid. The gradient corrosion-resistant coating comprises a transition bonding layer, an anti-oxidation layer and a corrosion-resistant and wear-resistant layer from inside to outside, and the thickness ratio of the transition bonding layer to the anti-oxidation layer to the corrosion-resistant and wear-resistant layer is 1: (2-3): (1.5-2). The preparation method comprises the steps of gel casting, hot pressed sintering, plasma spraying, vacuum annealing and the like. The bending strength of the turbine blade at the temperature of 1600 DEG C reaches 480-550 MPa, the molten salt corrosion rate at the temperature of 1500 DEG C is smaller than or equal to 0.01 mm / h, and the turbine blade can stably work for a long time in the ultra-high-temperature corrosion environment of aerospace engines, gas turbines and the like and has wide application prospects.

Description

Technical Field

[0001] This invention relates to the field of turbine engine technology, and in particular to a turbine blade made of ultra-high temperature corrosion-resistant ceramic matrix composite material. Background Technology

[0002] Turbine blades, as core hot-end components of power equipment such as aerospace engines and gas turbines, operate in extremely harsh environments. They must withstand ultra-high temperatures exceeding 1200°C, high-frequency thermal cycling, high-speed airflow erosion, and corrosive media such as molten salts and acidic gases from fuel combustion products. As power equipment develops towards higher thrust-to-weight ratios and higher efficiency, increasingly stringent requirements are placed on the high-temperature resistance, corrosion resistance, and structural stability of turbine blades. Currently, the mainstream turbine blade materials mainly include high-temperature alloys and traditional ceramic matrix composites. While high-temperature alloys possess good mechanical properties, their strength decreases sharply in ultra-high-temperature environments above 1500°C, and their resistance to molten salts and high-temperature combustion gas corrosion is limited, requiring complex cooling systems. This not only increases the difficulty of blade structural design but also reduces the overall efficiency of the engine. Traditional ceramic matrix composites use a single SiC or Si3N4 matrix and are reinforced with a single fiber or particles. Although they have significantly improved the high-temperature resistance of high-temperature alloys, they have problems such as uneven dispersion of reinforcing phase, low interfacial bonding strength, and poor thermal shock resistance. In addition, the surface lacks an effective protective coating, and is prone to oxidation and corrosion in high-temperature corrosive environments, leading to premature blade failure.

[0003] Furthermore, existing ceramic matrix composite turbine blade manufacturing processes mostly employ traditional compression molding or chemical vapor infiltration methods, which suffer from drawbacks such as low molding precision, difficulty in densification, and long production cycles, making it difficult to meet the manufacturing requirements of complex blade structures. Therefore, developing a ceramic matrix composite turbine blade that combines excellent ultra-high temperature mechanical properties, strong corrosion resistance, and a stable structure has become a key technical challenge in overcoming the performance bottleneck of power equipment. Summary of the Invention

[0004] The purpose of this invention is to provide an ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade to solve the above-mentioned problems.

[0005] This invention provides an ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade, comprising a blade matrix and a gradient corrosion-resistant coating composited on the surface of the blade matrix; the blade matrix is ​​a ceramic matrix composite material, composed of a reinforcing phase, a matrix phase and a sintering aid, with each component by mass percentage being: 25-40% reinforcing phase, 55-70% matrix phase and 1-5% sintering aid; the gradient corrosion-resistant coating consists of a transition bonding layer, an anti-oxidation layer and a corrosion-resistant and wear-resistant layer from the inside out, with the thickness ratio of each layer being 1:(2-3):(1.5-2).

[0006] Preferably, the reinforcing phase is a hybrid reinforcement of continuous SiC fibers and ZrB2 whiskers, wherein the mass ratio of continuous SiC fibers to ZrB2 whiskers is (3-5):1; the diameter of the continuous SiC fibers is 10-15 μm and the aspect ratio is ≥1000; the diameter of the ZrB2 whiskers is 0.5-2 μm and the aspect ratio is 20-50.

[0007] Preferably, the matrix phase is a SiC-Si3N4 multiphase ceramic, wherein the mass ratio of SiC to Si3N4 is (2-3):1; the SiC is a nano-sized powder with a particle size of 50-100 nm; and the Si3N4 is a submicron-sized powder with a particle size of 200-500 nm.

[0008] Preferably, the sintering aid is a Y2O3-La2O3 composite aid, wherein the mass ratio of Y2O3 to La2O3 is (1-2):1; and the particle size of the sintering aid is ≤100nm.

[0009] Preferably, the transition bonding layer is a SiC-Y2O3 composite layer with a thickness of 50-100 μm, wherein the mass content of Y2O3 is 5-10%; the bonding strength between the transition bonding layer and the blade substrate is ≥30 MPa.

[0010] Preferably, the antioxidant layer is an Al2O3-ZrO2-Y2O3 multiphase layer with a thickness of 100-300 μm, and the components, by mass percentage, are: Al2O3 60-70%, ZrO2 25-35%, and Y2O3 3-5%; the oxidation weight gain of the antioxidant layer after being kept at 1600℃ in static air for 100 hours is ≤0.5 mg / cm³. 2 .

[0011] Preferably, the corrosion-resistant and wear-resistant layer is an HfO2-Y2O3-TaC composite layer with a thickness of 75-200μm, and the components by mass percentage are: HfO2 70-80%, Y2O3 5-10%, and TaC 10-15%; the microhardness of the corrosion-resistant and wear-resistant layer is ≥18GPa, and the corrosion rate after being kept at 1500℃ in a molten salt corrosion environment for 50h is ≤0.01mm / h.

[0012] Preferably, the method for preparing ultra-high temperature corrosion-resistant ceramic matrix composite turbine blades includes the following steps: (1) Preparation of blade matrix preform: After surface modification treatment of continuous SiC fibers, they are mixed with ZrB2 whiskers, SiC powder, Si3N4 powder and sintering aid in proportion, and the blade matrix preform is prepared by gel casting process. (2) Densification treatment: The blade substrate preform is placed in an inert gas protected furnace and densified by hot pressing sintering process. The sintering temperature is 1800-2000℃, the sintering pressure is 20-30MPa, and the holding time is 2-4h to obtain the blade substrate. (3) Preparation of gradient corrosion-resistant coating: The transition bonding layer, the anti-oxidation layer and the corrosion-resistant and wear-resistant layer are prepared sequentially on the surface of the blade substrate by plasma spraying process. The spraying power of the transition bonding layer is 30-40kW, the spraying power of the anti-oxidation layer is 40-50kW, and the spraying power of the corrosion-resistant and wear-resistant layer is 50-60kW. The spraying distance is 100-150mm. (4) Post-treatment: The sprayed turbine blades are subjected to vacuum annealing at a temperature of 800-1000℃ and a holding time of 1-2h. They are then cooled to room temperature in the furnace to obtain ultra-high temperature corrosion resistant ceramic matrix composite turbine blades.

[0013] Preferably, the surface modification treatment of the continuous SiC fiber in step (1) is specifically as follows: the continuous SiC fiber is immersed in a KH550 ethanol solution with a mass concentration of 5-10%, ultrasonically treated for 30-60 min, and then dried at 120-150℃ for 2-3 h to complete the surface modification.

[0014] Preferably, the plasma gas used in step (3) for plasma spraying is an Ar-H2 mixture, wherein the volume ratio of Ar to H2 is (8-10):1, and the gas flow rate is 50-80 L / min.

[0015] Therefore, this invention employs an ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade, as described above. Through synergistic innovative design of the blade matrix composition and surface coating structure, it effectively solves the problems of insufficient high-temperature resistance, poor corrosion resistance, and low structural stability of existing turbine blade materials, demonstrating significant technical advantages. The blade matrix adopts a hybrid reinforcement design of continuous SiC fibers and ZrB2 whiskers. Compared with a single reinforcing phase, the three-dimensional reinforcement network formed by the two can effectively transfer and disperse stress. Among them, the continuous SiC fibers exhibit excellent fracture resistance, while the ZrB2 whiskers significantly improve the hardness and wear resistance of the matrix. Combined with the high-temperature stability of the SiC-Si3N4 multiphase ceramic matrix, the blade matrix can still maintain high bending strength and thermal shock resistance at temperatures above 1600℃. The introduction of Y2O3-La2O3 composite sintering aid not only lowers the sintering temperature and promotes the densification of the matrix, but also reduces the generation of internal porosity and microcracks in the matrix, further improving the mechanical properties and resistance to corrosion media penetration of the matrix. The surface protection employs a layered design with gradient corrosion-resistant coatings to achieve complementary functions. The addition of Y2O3 in the transition bonding layer optimizes the interfacial bonding with the blade substrate, increasing the bonding strength to over 30 MPa and effectively preventing coating peeling. The multiphase structure of Al2O3-ZrO2-Y2O3 in the anti-oxidation layer forms a dense oxide film, with an oxidation weight gain of only 0.5 mg / cm³ after being kept at 1600℃ in static air for 100 hours. 2 The following significantly slows down the oxidation rate of the substrate. The synergistic effect of HfO2 and TaC in the corrosion-resistant and wear-resistant layer endows the coating with excellent high-temperature molten salt corrosion resistance and high hardness. The corrosion rate in a molten salt environment at 1500℃ is less than 0.01 mm / h, and the microhardness can reach over 18 GPa, effectively resisting the erosion of high-temperature airflow and corrosive media. Furthermore, the preparation process combining gel casting and hot-pressing sintering improves the forming accuracy and densification of the blades. The combination of plasma spraying and vacuum annealing ensures the uniformity and bonding stability of the coating, giving the turbine blade excellent overall performance. This turbine blade can operate stably for a long time in an ultra-high temperature corrosive environment of 1500-1600℃ without a complex cooling system. This not only extends the service life of the blades but also improves the thermal efficiency and thrust performance of the power equipment, providing key material support for the development of high-end power equipment in aerospace, energy, and other fields.

[0016] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0017] To better understand the above technical solutions, a detailed description of the specific implementation methods will be provided below. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0019] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0020] This invention provides an ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade, comprising a blade matrix and a gradient corrosion-resistant coating composited on the surface of the blade matrix; the blade matrix is ​​a ceramic matrix composite material, composed of a reinforcing phase, a matrix phase and a sintering aid, with each component by mass percentage being: 25-40% reinforcing phase, 55-70% matrix phase and 1-5% sintering aid; the gradient corrosion-resistant coating consists of a transition bonding layer, an anti-oxidation layer and a corrosion-resistant and wear-resistant layer from the inside out, with the thickness ratio of each layer being 1:(2-3):(1.5-2).

[0021] To further optimize the above technical solution, the reinforcing phase is a hybrid reinforcement of continuous SiC fibers and ZrB2 whiskers, wherein the mass ratio of continuous SiC fibers to ZrB2 whiskers is (3-5):1; the diameter of the continuous SiC fibers is 10-15 μm and the aspect ratio is ≥1000; the diameter of the ZrB2 whiskers is 0.5-2 μm and the aspect ratio is 20-50.

[0022] To further optimize the above technical solution, the matrix phase is SiC-Si3N4 multiphase ceramic, wherein the mass ratio of SiC to Si3N4 is (2-3):1; the SiC is nanoscale powder with a particle size of 50-100nm; the Si3N4 is submicron-scale powder with a particle size of 200-500nm.

[0023] To further optimize the above technical solution, the sintering aid is a Y2O3-La2O3 composite aid, wherein the mass ratio of Y2O3 to La2O3 is (1-2):1; the particle size of the sintering aid is ≤100nm.

[0024] To further optimize the above technical solution, the transition bonding layer is a SiC-Y2O3 composite layer with a thickness of 50-100μm, wherein the mass content of Y2O3 is 5-10%; the bonding strength between the transition bonding layer and the blade substrate is ≥30MPa.

[0025] To further optimize the above technical solution, the antioxidant layer is an Al2O3-ZrO2-Y2O3 multiphase layer with a thickness of 100-300 μm. The components, by mass percentage, are: Al2O3 60-70%, ZrO2 25-35%, and Y2O3 3-5%. The oxidation weight gain of the antioxidant layer after being kept at 1600℃ in static air for 100 hours is ≤0.5 mg / cm³. 2 .

[0026] To further optimize the above technical solution, the corrosion-resistant and wear-resistant layer is an HfO2-Y2O3-TaC composite layer with a thickness of 75-200μm. The components, by mass percentage, are: HfO2 70-80%, Y2O3 5-10%, and TaC 10-15%. The microhardness of the corrosion-resistant and wear-resistant layer is ≥18GPa, and the corrosion rate after being kept at 1500℃ in a molten salt corrosion environment for 50h is ≤0.01mm / h.

[0027] To further optimize the above technical solution, the preparation method of ultra-high temperature corrosion-resistant ceramic matrix composite turbine blades includes the following steps: (1) Preparation of blade matrix preform: After surface modification treatment of continuous SiC fibers, they are mixed with ZrB2 whiskers, SiC powder, Si3N4 powder and sintering aid in proportion, and the blade matrix preform is prepared by gel casting process. (2) Densification treatment: The blade substrate preform is placed in an inert gas protected furnace and densified by hot pressing sintering process. The sintering temperature is 1800-2000℃, the sintering pressure is 20-30MPa, and the holding time is 2-4h to obtain the blade substrate. (3) Preparation of gradient corrosion-resistant coating: The transition bonding layer, the anti-oxidation layer and the corrosion-resistant and wear-resistant layer are prepared sequentially on the surface of the blade substrate by plasma spraying process. The spraying power of the transition bonding layer is 30-40kW, the spraying power of the anti-oxidation layer is 40-50kW, and the spraying power of the corrosion-resistant and wear-resistant layer is 50-60kW. The spraying distance is 100-150mm. (4) Post-treatment: The sprayed turbine blades are subjected to vacuum annealing at a temperature of 800-1000℃ and a holding time of 1-2h. They are then cooled to room temperature in the furnace to obtain ultra-high temperature corrosion resistant ceramic matrix composite turbine blades.

[0028] To further optimize the above technical solution, the surface modification treatment of the continuous SiC fiber in step (1) is as follows: the continuous SiC fiber is immersed in a KH550 ethanol solution with a mass concentration of 5-10%, ultrasonically treated for 30-60 min, and then dried at 120-150℃ for 2-3 h to complete the surface modification.

[0029] To further optimize the above technical solution, the plasma gas used in step (3) for plasma spraying is an Ar-H2 mixture, wherein the volume ratio of Ar to H2 is (8-10):1, and the gas flow rate is 50-80 L / min.

[0030] To provide a clearer and more detailed description of the ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade provided by the embodiments of the present invention, the following description will be based on specific embodiments.

[0031] Example 1 The turbine blade matrix composition by mass percentage is as follows: 25% reinforcing phase, of which continuous SiC fibers account for 20% and ZrB2 whiskers account for 5%, with a mass ratio of 4:1; 70% matrix phase, of which SiC accounts for 46.7% and Si3N4 accounts for 23.3%, with a mass ratio of 2:1; and 5% sintering aid, of which Y2O3 accounts for 3.3% and La2O3 accounts for 1.7%, with a mass ratio of 2:1. The gradient corrosion-resistant coating consists of, from the inside out, a SiC-Y2O3 composite transition bonding layer (Y2O3 mass content 8%, thickness 50μm), an Al2O3-ZrO2-Y2O3 multiphase antioxidant layer (Al2O3 65%, ZrO2 30%, Y2O3 5%, thickness 100μm), and an HfO2-Y2O3-TaC composite corrosion-resistant and wear-resistant layer (HfO2 75%, Y2O3 10%, TaC 15%, thickness 75μm), with a thickness ratio of 1:2:1.5.

[0032] The preparation process is as follows: First, continuous SiC fibers are immersed in an 8% KH550 ethanol solution and ultrasonically treated for 45 min, then dried at 130℃ for 2.5 h to complete surface modification; then, the modified continuous SiC fibers, ZrB2 whiskers and various powdered additives are weighed according to the proportion, deionized water and dispersant are added and stirred at high speed for 30 min, organic monomers and crosslinking agents are added and ultrasonically dispersed for 20 min to form a uniform slurry, which is then injected into a mold and kept at 60℃ for 2 h for gel solidification. The preform is then demolded to obtain the blade matrix preform; the preform is placed in a graphite sintering furnace, protected by argon gas, and sintered at 5℃ / min. The temperature was raised to 1800℃, and hot-pressing sintering was performed by applying a pressure of 20MPa and holding for 4 hours. After cooling in the furnace, a blade substrate with a density of 95.2% was obtained. Plasma spraying equipment was used, with an Ar-H2 mixture of 9:1 volume ratio and 60L / min flow rate as the plasma gas. Various coatings were sequentially sprayed onto the surface of the blade substrate. The spraying power for the transition bonding layer, anti-oxidation layer, and corrosion-resistant and wear-resistant layer was 30kW, 40kW, and 50kW, respectively, and the spraying distances were 120mm, 100mm, and 150mm, respectively. Finally, the sprayed blade was placed in a vacuum annealing furnace and evacuated to a vacuum of 1×10⁻⁶. - 3 Pa, heat to 800℃ and hold for 2 hours, then cool to room temperature in the furnace to obtain the target turbine blade.

[0033] Performance testing results show that the blade matrix has a bending strength of 480 MPa at 1600℃, the bonding strength between the transition bonding layer and the matrix is ​​32 MPa, and the oxidation weight gain of the anti-oxidation layer after 100 hours of static air exposure at 1600℃ is 0.42 mg / cm³. 2 The corrosion-resistant and wear-resistant layer has a microhardness of 18.5 GPa and a corrosion rate of 0.008 mm / h after being kept at 1500℃ in a molten salt (Na2SO4-K2SO4 mass ratio 1:1) corrosion environment for 50 hours.

[0034] Example 2 The turbine blade matrix composition, by mass percentage, is as follows: reinforcing phase 32%, comprising 24% continuous SiC fibers and 8% ZrB2 whiskers, with a mass ratio of 3:1; matrix phase 65%, comprising 39% SiC and 26% Si3N4, with a mass ratio of 1.5:1; sintering aid 3%, comprising 2% Y2O3 and 1% La2O3, with a mass ratio of 2:1. In the gradient corrosion-resistant coating, the transition bonding layer is a SiC-Y2O3 composite layer containing 5% Y2O3, with a thickness of 80 μm; the anti-oxidation layer is a multiphase layer of 60% Al2O3, 35% ZrO2, and 5% Y2O3, with a thickness of 200 μm; and the corrosion-resistant and wear-resistant layer is a composite layer of 70% HfO2, 10% Y2O3, and 20% TaC, with a thickness of 130 μm, and the thickness ratio of each layer is 1:2.5:1.6.

[0035] In the preparation process, continuous SiC fibers were first soaked in a 5% KH550 ethanol solution and ultrasonically treated for 60 min, then dried at 120℃ for 3 h to complete surface modification. The components were then mixed in proportion, and deionized water, dispersant, and binder were added and stirred until homogeneous. The mixture was then gel-molded at 55℃ for 3 h to cure and demold, yielding a preform. The preform was then hot-pressed under argon protection, heated to 1900℃ at a rate of 6℃ / min, and held at 25MPa for 3 h. After cooling, a blade matrix with a density of 96.5% was obtained. An Ar-H2 mixed gas with a volume ratio of 8:1 and a flow rate of 50 L / min was used as the plasma gas to sequentially spray each coating layer. The spraying power for the transition bonding layer, anti-oxidation layer, and corrosion-resistant and wear-resistant layer was 35kW, 45kW, and 55kW, respectively, with spraying distances of 130mm, 120mm, and 120mm, respectively. Finally, the blade was placed under a vacuum of 5×10⁻⁶. -3 Under the condition of Pa, vacuum annealing is performed at 900℃ for 1.5h, and the finished product is obtained by furnace cooling.

[0036] Performance testing showed that the blade substrate had a bending strength of 520 MPa at 1600℃, a bonding strength of 35 MPa in the transition bonding layer, and an oxidation weight gain of only 0.38 mg / cm³ in the anti-oxidation layer after 100 hours of static air oxidation at 1600℃. 2 The corrosion-resistant and wear-resistant layer has a microhardness of 19.2 GPa, and the corrosion rate after 50 hours of molten salt corrosion at 1500℃ is 0.007 mm / h.

[0037] Example 3 The turbine blade matrix composition, by mass percentage, is as follows: reinforcing phase 40%, comprising 33.3% continuous SiC fibers and 6.7% ZrB2 whiskers in a 5:1 mass ratio; matrix phase 59%, comprising 44.3% SiC and 14.7% Si3N4 in a 3:1 mass ratio; sintering aid 1%, comprising 0.5% Y2O3 and 0.5% La2O3 in a 1:1 mass ratio. The transition bonding layer of the gradient corrosion-resistant coating is a SiC-Y2O3 composite layer containing 10% Y2O3, with a thickness of 100 μm; the anti-oxidation layer is a multiphase layer of 70% Al2O3, 27% ZrO2, and 3% Y2O3, with a thickness of 300 μm; the corrosion-resistant and wear-resistant layer is a composite layer of 80% HfO2, 5% Y2O3, and 15% TaC, with a thickness of 200 μm, and the thickness ratio of each layer is 1:3:2.

[0038] The preparation steps are as follows: Continuous SiC fibers are soaked in a 10% KH550 ethanol solution, ultrasonically treated for 30 min, and then dried at 150℃ for 2 h to complete surface modification; the components are mixed in proportion to prepare a slurry, which is then cured using a gel casting process at 65℃ for 1.5 h to obtain a blade substrate preform; the preform is hot-pressed and sintered under argon protection, heated to 2000℃ at a heating rate of 8℃ / min, and held at 30MPa pressure for 2 h, and then cooled to obtain a blade substrate with a density of 97.1%; during plasma spraying, an Ar-H2 mixed gas with a volume ratio of 10:1 and a flow rate of 80L / min is selected as the plasma gas, and the spraying power for the transition bonding layer, the anti-oxidation layer, and the corrosion-resistant and wear-resistant layer is 40kW, 50kW, and 60kW, respectively, with spraying distances of 100mm, 110mm, and 100mm, respectively; finally, the blade is placed under a vacuum of 1×10 -4 Vacuum annealing was performed in a Pa annealing furnace at 1000℃ for 1 hour, followed by furnace cooling to room temperature to complete the preparation.

[0039] Performance test results show that the blade substrate has a bending strength of up to 550 MPa at 1600℃, the transition bonding layer has a bonding strength of 38 MPa, and the anti-oxidation layer has an oxidation weight gain of only 0.32 mg / cm³ after 100 hours in static air at 1600℃. 2 The corrosion-resistant and wear-resistant layer has a microhardness of 20.1 GPa, and its corrosion rate is as low as 0.005 mm / h after being kept in a molten salt corrosion environment at 1500℃ for 50 hours. It exhibits the best overall performance.

[0040] Examples 1-3 all used commercially available industrial-grade raw materials and successfully prepared turbine blades with complete structure and stable performance through a combination of mature processes such as gel injection molding, hot pressing sintering, plasma spraying and vacuum annealing. The density of the blade matrix reached more than 95%, and the gradient coating layers were tightly bonded without obvious peeling. It can be seen that it does not rely on special equipment or scarce raw materials and has the basic conditions for industrial production.

[0041] The turbine blades in Examples 1-3 all exhibited excellent ultra-high temperature mechanical properties and corrosion and wear resistance. The bending strength of the blade matrix at 1600℃ ranged from a minimum of 480MPa to a maximum of 550MPa, far exceeding the high-temperature strength limit of traditional ceramic matrix composite turbine blades. The synergistic effect of the gradient corrosion-resistant coating was significant, with the bonding strength between the transition bonding layer and the matrix exceeding 30MPa. The oxidation weight gain of the anti-oxidation layer after 100 hours in static air at 1600℃ was less than 0.5mg / cm³. 2 The corrosion-resistant and wear-resistant layer has a corrosion rate of less than 0.01 mm / h in a molten salt corrosion environment at 1500℃ for 50 hours, and its microhardness exceeds 18 GPa. It can withstand multiple tests of ultra-high temperature oxidation, molten salt corrosion and high-speed airflow erosion at the same time.

[0042] The performance differences between Examples 1-3 clearly reflect the optimization potential of component ratios and process parameters: increasing the proportion of the reinforcing phase from 25% in Example 1 to 40% in Example 3, and increasing the sintering temperature and pressure from 1800℃ / 20MPa to 2000℃ / 30MPa, both significantly improve the density and high-temperature strength of the blade substrate; adjusting the proportion of functional components in each layer of the gradient coating, such as increasing the Al2O3 content in the antioxidant layer from 60% to 70%, can specifically optimize certain performance indicators. This parameter adjustability allows the present invention to flexibly design product solutions according to the needs of different application scenarios. For example, Example 1 has a lower cost and is suitable for cost-sensitive fields such as industrial gas turbines, while Example 3 has the best performance and can meet the stringent requirements of high thrust-to-weight ratio and high reliability for aerospace engines, demonstrating broad application prospects.

[0043] Therefore, this invention employs an ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade, as described above. Through synergistic innovative design of the blade matrix composition and surface coating structure, it effectively solves the problems of insufficient high-temperature resistance, poor corrosion resistance, and low structural stability of existing turbine blade materials, demonstrating significant technical advantages. The blade matrix adopts a hybrid reinforcement design of continuous SiC fibers and ZrB2 whiskers. Compared with a single reinforcing phase, the three-dimensional reinforcement network formed by the two can effectively transfer and disperse stress. Among them, the continuous SiC fibers exhibit excellent fracture resistance, while the ZrB2 whiskers significantly improve the hardness and wear resistance of the matrix. Combined with the high-temperature stability of the SiC-Si3N4 multiphase ceramic matrix, the blade matrix can still maintain high bending strength and thermal shock resistance at temperatures above 1600℃. The introduction of Y2O3-La2O3 composite sintering aid not only lowers the sintering temperature and promotes the densification of the matrix, but also reduces the generation of internal porosity and microcracks in the matrix, further improving the mechanical properties and resistance to corrosion media penetration of the matrix.

[0044] The surface protection employs a layered design with gradient corrosion-resistant coatings to achieve complementary functions. The addition of Y2O3 in the transition bonding layer optimizes the interfacial bonding with the blade substrate, increasing the bonding strength to over 30 MPa and effectively preventing coating peeling. The multiphase structure of Al2O3-ZrO2-Y2O3 in the anti-oxidation layer forms a dense oxide film, with an oxidation weight gain of only 0.5 mg / cm³ after being kept at 1600℃ in static air for 100 hours. 2 The following measures significantly slow down the oxidation rate of the substrate; the synergistic effect of HfO2 and TaC in the corrosion-resistant and wear-resistant layer endows the coating with excellent high-temperature molten salt corrosion resistance and high hardness. The corrosion rate is less than 0.01 mm / h in a molten salt environment at 1500℃, and the microhardness can reach more than 18 GPa, effectively resisting the erosion of high-temperature airflow and corrosive media.

[0045] Furthermore, the manufacturing process combining gel casting and hot-pressing sintering employed in this invention improves the forming precision and densification of the blades. The combination of plasma spraying and vacuum annealing ensures the uniformity and bonding stability of the coating, resulting in excellent overall performance for the turbine blades. These turbine blades can operate stably for extended periods in ultra-high temperature corrosive environments of 1500-1600℃ without the need for complex cooling systems. This not only extends the blade's service life but also improves the thermal efficiency and thrust performance of power equipment, providing crucial material support for the development of high-end power equipment in aerospace, energy, and other fields.

[0046] 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A turbine blade made of ultra-high temperature corrosion-resistant ceramic matrix composite material, characterized in that, The blade includes a blade substrate and a gradient corrosion-resistant coating composited on the surface of the blade substrate. The blade substrate is a ceramic matrix composite material, consisting of a reinforcing phase, a matrix phase, and a sintering aid. The components are expressed as follows by mass percentage: 25-40% reinforcing phase, 55-70% matrix phase, and 1-5% sintering aid. The gradient corrosion-resistant coating consists of a transition bonding layer, an anti-oxidation layer, and a corrosion-resistant and wear-resistant layer from the inside out, with a thickness ratio of 1:(2-3):(1.5-2).

2. The ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade according to claim 1, characterized in that, The reinforcing phase is a hybrid reinforcement of continuous SiC fibers and ZrB2 whiskers, wherein the mass ratio of continuous SiC fibers to ZrB2 whiskers is (3-5):1; the diameter of the continuous SiC fibers is 10-15 μm and the aspect ratio is ≥1000; the diameter of the ZrB2 whiskers is 0.5-2 μm and the aspect ratio is 20-50.

3. The ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade according to claim 1, characterized in that, The matrix phase is a SiC-Si3N4 multiphase ceramic, wherein the mass ratio of SiC to Si3N4 is (2-3):1; the SiC is a nano-sized powder with a particle size of 50-100nm; and the Si3N4 is a submicron-sized powder with a particle size of 200-500nm.

4. The ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade according to claim 1, characterized in that, The sintering aid is a Y2O3-La2O3 composite aid, wherein the mass ratio of Y2O3 to La2O3 is (1-2):1; the particle size of the sintering aid is ≤100nm.

5. The ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade according to claim 1, characterized in that, The transition bonding layer is a SiC-Y2O3 composite layer with a thickness of 50-100μm, wherein the mass content of Y2O3 is 5-10%; the bonding strength between the transition bonding layer and the blade substrate is ≥30MPa.

6. The ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade according to claim 1, characterized in that, The antioxidant layer is an Al2O3-ZrO2-Y2O3 multiphase layer with a thickness of 100-300 μm. The components, by mass percentage, are: Al2O3 60-70%, ZrO2 25-35%, and Y2O3 3-5%. The oxidation weight gain of the antioxidant layer after being kept at 1600℃ in static air for 100 hours is ≤0.5 mg / cm³. 2 .

7. The ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade according to claim 1, characterized in that, The corrosion-resistant and wear-resistant layer is an HfO2-Y2O3-TaC composite layer with a thickness of 75-200μm. The components, by mass percentage, are: HfO2 70-80%, Y2O3 5-10%, and TaC 10-15%. The microhardness of the corrosion-resistant and wear-resistant layer is ≥18GPa, and the corrosion rate after being kept at 1500℃ in a molten salt corrosion environment for 50h is ≤0.01mm / h.

8. The ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade according to claim 1, characterized in that, Its preparation method includes the following steps: (1) Preparation of blade matrix preform: After surface modification treatment of continuous SiC fibers, they are mixed with ZrB2 whiskers, SiC powder, Si3N4 powder and sintering aid in proportion, and the blade matrix preform is prepared by gel casting process. (2) Densification treatment: The blade substrate preform is placed in an inert gas protected furnace and densified by hot pressing sintering process. The sintering temperature is 1800-2000℃, the sintering pressure is 20-30MPa, and the holding time is 2-4h to obtain the blade substrate. (3) Preparation of gradient corrosion-resistant coating: The transition bonding layer, the anti-oxidation layer and the corrosion-resistant and wear-resistant layer are prepared sequentially on the surface of the blade substrate by plasma spraying process. The spraying power of the transition bonding layer is 30-40kW, the spraying power of the anti-oxidation layer is 40-50kW, and the spraying power of the corrosion-resistant and wear-resistant layer is 50-60kW. The spraying distance is 100-150mm. (4) Post-treatment: The sprayed turbine blades are subjected to vacuum annealing at a temperature of 800-1000℃ and a holding time of 1-2h. They are then cooled to room temperature in the furnace to obtain ultra-high temperature corrosion resistant ceramic matrix composite turbine blades.

9. The ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade according to claim 8, characterized in that, The surface modification treatment of the continuous SiC fiber in step (1) is as follows: the continuous SiC fiber is immersed in a KH550 ethanol solution with a mass concentration of 5-10%, ultrasonically treated for 30-60 min, and then dried at 120-150℃ for 2-3 h to complete the surface modification.

10. The ultra-high temperature corrosion-resistant ceramic matrix composite turbine blade according to claim 8, characterized in that, The plasma gas used in step (3) for plasma spraying is an Ar-H2 mixture, wherein the volume ratio of Ar to H2 is (8-10):1, and the gas flow rate is 50-80 L / min.