Aero-engine blade and preparation method thereof

Abstract

The invention belongs to the technical field of material surface plating, and particularly relates to an aero-engine blade and a preparation method thereof. According to the preparation method, the component nano silicon carbide of the blade material is subjected to modification treatment, meanwhile, the carbon fiber composite material is introduced for common use, and the composite coating is formed on the surface through spraying treatment, so that the aero-engine blade is prepared, the cold and heat cycle resistance is effectively improved, and meanwhile, good erosion resistance is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of material surface plating, and in particular relates to an aero-engine blade and a preparation method thereof. Background Art

[0002] Aircraft engines are the core components of aircraft and are the key to ensuring the reliability, durability and economy of aircraft. Modern large commercial aircraft are required to fly faster, higher and quieter, which puts higher requirements on the performance of aircraft engines. Aircraft engine blades are key components in aircraft engines, mainly used for compressing air, combustion and generating thrust. They work in extreme environments of high temperature, high pressure and high speed, so they have extremely high requirements for materials, design and manufacturing processes. Composite materials have the advantages of high specific strength and modulus, good anti-flutter performance and strong designability. The use of composite blades can significantly reduce the weight of the blades themselves, thereby reducing the weight of the containment system, blade disk and its transmission system, which is of great significance to improving engine efficiency.

[0003] A Chinese patent (publication number CN104529458B) discloses a method for manufacturing a high-performance SiC ceramic-based composite aero-engine blade. The invention uses gel injection molding to prepare a blank with carbon fiber added, freeze-drying, degreasing and other processes to obtain a porous preform, and then impregnates and pyrolyzes an organic precursor multiple times, using the pyrolysis product to fill the pores of the preform to achieve initial density. In order to ensure the strength and density of the part, a hot isostatic pressing method is finally used to manufacture a high-performance composite aero-engine blade. However, the aero-engine blades in the prior art still have problems such as poor resistance to cold and hot cycles and need to improve erosion resistance, which seriously affect their application.

[0004] Therefore, how to modify the components of the blade material and form a composite coating on the surface through spraying treatment to prepare aircraft engine blades, effectively improve the resistance to cold and hot cycles, and obtain good erosion resistance has become a direction that needs to be focused on. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an aircraft engine blade and a method for preparing the same, aiming to solve the problems existing in the prior art of aircraft engine blades, such as poor resistance to cold and hot cycles and the need to improve erosion resistance.

[0006] The present invention prepares an aero-engine blade by modifying the nano silicon carbide component of the blade material, introducing a carbon fiber composite material for use together, and forming a composite coating on the surface by spraying, thereby effectively improving the resistance to cold and hot cycles and obtaining good erosion resistance.

[0007] The technical solution adopted by the present invention to solve the above technical problems is as follows: In the first aspect of the present invention, a method for preparing an aero-engine blade is provided, comprising the following steps: S1: By weight, mix 18-24 parts of acrylamide, 1-2 parts of N,N'-methylenebisacrylamide and 100-120 parts of deionized water to obtain a premixed solution, then add 10-20 parts of nano silicon carbide and 4-6 parts of carbon fiber and ultrasonically disperse evenly, and then add 60-70 parts of micro silicon carbide and 2-4 parts of sodium polyacrylate and stir evenly to obtain a slurry; S2: Carry out injection molding, freeze-drying and vacuum degreasing on the slurry to obtain a composite material blade; S3: Pretreat the composite material blade, and then spray the coating powder on the composite material blade by flame spraying to form a composite coating, thereby obtaining an aero-engine blade.

[0008] As a preferred technical solution of the present invention, the weight parts of the acrylamide can be 18 parts, 20 parts, 22 parts, 24 parts, etc.

[0009] As a preferred technical solution of the present invention, the weight parts of the N,N'-methylenebisacrylamide can be 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, etc.

[0010] As a preferred technical solution of the present invention, the weight parts of the nano silicon carbide can be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, etc.

[0011] As a preferred technical solution of the present invention, the weight parts of the carbon fiber can be 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, etc.

[0012] As a preferred technical solution of the present invention, the weight parts of the micro silicon carbide can be 60 parts, 62 parts, 64 parts, 66 parts, 68 parts, 70 parts, etc.

[0013] As a preferred technical solution of the present invention, the weight parts of the sodium polyacrylate can be 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, etc.

[0014] As a preferred technical solution of the present invention, the preparation method of the coating powder includes: by weight, add 4-8 parts of chromium nitrate, 4-6 parts of lanthanum nitrate and 1-3 parts of calcium nitrate to 180-200 parts of deionized water and dissolve fully, then add 4-8 parts of citric acid and 2-6 parts of ethylene glycol and stir to dissolve, and then add 4-8 parts of commercially available nickel-chromium alloy powder and carry out heat-up treatment to obtain a modified nickel-chromium alloy powder; mix and ball-mill 20-30 parts of the modified nickel-chromium alloy powder, 20-30 parts of tungsten carbide powder and 40-50 parts of chromium carbide powder to obtain the coating powder.

[0015] As a preferred technical solution of the present invention, the conditions for injection molding include: uniformly stirring 200-300 parts of slurry, 2-4 parts of a 25% tetramethylethylenediamine solution by mass fraction, and 12-16 parts of a 30% ammonium persulfate solution by mass fraction, then performing vacuum casting into a blade mold, and standing at room temperature for 30-40 min.

[0016] As a preferred technical solution of the present invention, the conditions for vacuum degreasing include: placing it in an argon atmosphere, first heating to 200 °C at a rate of 5 °C / min, then heating to 700 °C at a rate of 1 °C / min, and finally heating to 900 °C at a rate of 2 °C / min, and holding for 50-60 min.

[0017] As a preferred technical solution of the present invention, the nano silicon carbide is modified nano silicon carbide; As a preferred technical solution of the present invention, the preparation method of the modified nano silicon carbide includes: by weight, dispersing 2-4 parts of commercially available nano silicon carbide in 200-300 parts of a polyethylene glycol solution with a mass fraction of 4-8% to obtain solution A, dispersing 1-3 parts of dopamine hydrochloride and 3-5 parts of tris(hydroxymethyl)aminomethane in 2000-2200 parts of deionized water to obtain solution B, adding 200-300 parts of solution A to 2000-2200 parts of solution B, and then adding 0.4-0.8 parts of nickel chloride hexahydrate for modification treatment to obtain modified nano silicon carbide.

[0018] As a preferred technical solution of the present invention, the conditions for the modification treatment include: adjusting the pH to 8.4-8.8, stirring at 35-40 °C for 10-12 h, centrifuging, washing with water, and freeze-drying.

[0019] As a preferred technical solution of the present invention, the particle size of the commercially available nano silicon carbide is 20-100 nm.

[0020] During the high-temperature sintering process, the modified nano silicon carbide will form a nitrogen-doped carbon-coated silicon carbide / nickel nanocomposite. Nickel has good ductility, creep resistance, and high-temperature stability, which can improve the toughness of the composite material, inhibit crack propagation, and enhance the overall strength through chemical bonding at the interface with nano silicon carbide; at the same time, the nitrogen-doped carbon coating layer can inhibit the interface oxidation and element diffusion between nano silicon carbide and nickel at high temperatures, maintain the long-term stability of the material, and comprehensively improve the thermal shock resistance of aero-engine blades.

[0021] As a preferred technical solution of the present invention, the carbon fiber is a carbon fiber composite material; The preparation method of the carbon fiber composite material includes: first, pretreat the commercially available carbon fiber on the surface, then immerse it in a 1 - 3 mg / mL polyethyleneimine solution for 50 - 60 min, and dry it to obtain grafted carbon fiber; add the grafted carbon fiber into a 4 mg / mL graphene oxide dispersion solution and immerse it for 2 - 4 h, and then perform vacuum drying to obtain the carbon fiber composite material.

[0022] As a preferred technical solution of the present invention, the conditions of the surface pretreatment include: first immerse the commercially available carbon fiber in acetone at 70 - 80 °C for 2 - 4 h, wash it with water and dry it, then heat it in concentrated nitric acid at 75 - 80 °C for 2 - 3 h, wash it with water, and dry it.

[0023] The carbon fiber composite material introduces graphene oxide through polyethyleneimine as a bridging agent. When repeatedly switching between high temperature and low temperature, the high thermal conductivity of graphene oxide helps to quickly and evenly conduct heat, reduce the thermal stress caused by the temperature gradient. At the same time, graphene oxide can reduce local stress concentration by absorbing and dispersing external loads, thereby reducing the fatigue damage of the material caused by thermal cycling.

[0024] As a preferred technical solution of the present invention, the conditions of the heating treatment include: first keep the temperature at 120 - 130 °C for 10 - 12 h, then keep the temperature at 700 - 800 °C for 2 - 4 h, cool it to room temperature, and crush it.

[0025] As a preferred technical solution of the present invention, the conditions of the flame spraying include: the air flow rate is 90 - 100 L / min, the propylene flow rate is 80 - 90 L / min, the nitrogen flow rate is 35 - 40 L / min, the hydrogen flow rate is 45 - 50 L / min, the powder feeding rate is 120 - 130 g / min, the cooling gas pressure is 0.3 - 0.5 MPa, and the spraying distance is 140 - 160 mm.

[0026] As a preferred technical solution of the present invention, the conditions of the pretreatment include: first clean it with absolute ethanol, and then perform sandblasting treatment so that the surface roughness of the composite material blade is 2.4 - 2.6 μm.

[0027] The composite coating can change the phase composition and distribution of the coating through the doping of lanthanum elements, forming a denser microstructure. The dense coating can effectively block the intrusion of erosion particles, reduce the local stress concentration during particle impact, reduce material loss, thereby improving the erosion resistance of aeroengine blades; at the same time, the lanthanum - doped coating may have a certain degree of dynamic self - healing effect at high temperatures, that is, the microcracks in the coating will partially heal due to the migration of lanthanum ions, thereby delaying crack propagation and obtaining good resistance to thermal cycling performance.

[0028] The second aspect of the present invention provides an aeroengine blade prepared by the method described in the first aspect.

[0029] Compared with the prior art, the present invention has the following beneficial effects: (1) During the high-temperature sintering process, the modified nano-silicon carbide of the present invention will form a nitrogen-doped carbon coating layer. Nitrogen atoms will introduce additional electron density and strengthen electron coupling. The graphitized carbon layer on the surface of the carbon fiber composite material and the grafted graphene oxide both have the aromatic ring structure of hybrid carbon atoms, and can undergo π-π conjugation effects with the nitrogen-doped carbon coating layer during the sintering process. With the combined action of the composite coating, the anti-thermal and cold cycle performance and erosion resistance of the aeroengine blade are effectively improved.

[0030] (2) During the high-temperature sintering process, the modified nano-silicon carbide of the present invention will form a nitrogen-doped carbon-coated silicon carbide / nickel nanocomposite. Nickel has good ductility, creep resistance, and high-temperature stability, which can improve the toughness of the composite material, inhibit crack propagation, and enhance the overall strength through the interfacial bonding with nano-silicon carbide (hydrochloric acid dopamine undergoes self-polymerization reaction on the surface of silicon carbide. At the same time, due to the negatively charged hydrochloric acid dopamine monomer, it can chelate with the positively charged nickel ions in nickel chloride hexahydrate. During the high-temperature treatment process, nickel ions are reduced to elemental nickel and embedded on the surface of silicon carbide); at the same time, the nitrogen-doped carbon coating layer can inhibit the interfacial oxidation and element diffusion between nano-silicon carbide and nickel at high temperatures, maintain the long-term stability of the material, and comprehensively improve the anti-thermal and cold cycle performance of the aeroengine blade.

[0031] (3) The carbon fiber composite material of the present invention introduces graphene oxide through polyethyleneimine as a bridging agent. When repeatedly switching between high and low temperatures, the high thermal conductivity of graphene oxide helps to quickly and evenly conduct heat, reduce thermal stress caused by temperature gradients. At the same time, graphene oxide can absorb and disperse external loads, reduce local stress concentration, and thus reduce fatigue damage caused by thermal and cold cycles to the material.

[0032] (4) The composite coating of the present invention can change the phase composition and distribution of the coating through the doping of lanthanum elements, forming a denser microstructure. The dense coating can effectively block the intrusion of erosion particles, reduce local stress concentration during particle impact, reduce material loss, and thus improve the erosion resistance of the aeroengine blade; at the same time, the lanthanum-doped coating may undergo a certain degree of dynamic self-healing effect at high temperatures, that is, the microcracks in the coating will partially heal due to the migration of lanthanum ions, thus delaying crack propagation and obtaining good anti-thermal and cold cycle performance. Detailed implementation manners

[0033] To facilitate the understanding of the present invention, the following examples are listed. Those skilled in the art should understand that the said examples are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0034] The sources of some components in the examples and comparative examples are as follows: Acrylamide, CAS No. 79-06-1, purchased from Sinopharm Chemical Reagent Co., Ltd.; N,N'-Methylenebisacrylamide, CAS No. 110-26-9, purchased from Shanghai Macklin Biochemical Co., Ltd.; Commercially available nano-silicon carbide I, product number S104653, particle size of 40 nm, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Commercially available nano-silicon carbide II, product number S121696, particle size of 700 nm, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Commercially available carbon fiber, model SYT45, purchased from Zhongfu Shenying Carbon Fiber Co., Ltd.; Micron-sized silicon carbide, model MG-SiC-03, particle size of 8 μm, purchased from Shanghai Maoguo Nano Technology Co., Ltd.; Sodium polyacrylate, CAS No. 9003-04-7, purchased from Sinopharm Chemical Reagent Co., Ltd.; Tetramethylethylenediamine, CAS No. 110-18-9, purchased from Shanghai Macklin Biochemical Co., Ltd.; Ammonium persulfate, CAS No. 7727-54-0, purchased from Sinopharm Chemical Reagent Co., Ltd.; Polyethylene glycol, product number P103725, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Hydrochloride dopamine, CAS No. 62-31-7, purchased from Shanghai Macklin Biochemical Co., Ltd.; Tris(hydroxymethyl)aminomethane, CAS No. 77-86-1, purchased from Shanghai Macklin Biochemical Co., Ltd.; Nickel chloride hexahydrate, CAS No. 7791-20-0, purchased from Sinopharm Chemical Reagent Co., Ltd.; Acetone, CAS No. 67-64-1, purchased from Sinopharm Chemical Reagent Co., Ltd.; Concentrated nitric acid, CAS No. 7697-37-2, purchased from Sinopharm Chemical Reagent Co., Ltd.; Polyethyleneimine, CAS No. 9002-98-6, purchased from Shanghai Macklin Biochemical Co., Ltd.; Graphene oxide dispersion, product number G466617, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Chromium nitrate, CAS No. 7789-02-8, purchased from Sinopharm Chemical Reagent Co., Ltd.; Lanthanum nitrate, CAS No. 10277-43-7, was purchased from Shanghai Macklin Biochemical Co., Ltd. Calcium nitrate, CAS No. 13477-34-4, was purchased from Sinopharm Chemical Reagent Co., Ltd. Citric acid, CAS No. 77-92-9, was purchased from Shanghai Macklin Biochemical Co., Ltd. Ethylene glycol, CAS No. 107-21-1, was purchased from Sinopharm Chemical Reagent Co., Ltd. Commercially available nickel-chromium alloy powder, product number R168690, was purchased from Shanghai Huayuan Century Trading Co., Ltd. Tungsten carbide powder, product number T111337, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Chromium carbide powder, product number R020287, was purchased from Shanghai Huayuan Century Trading Co., Ltd.

[0035] Example 1

[0036] This example provides a method for preparing an aeroengine blade, including the following steps: S1: By weight, 24 parts of acrylamide, 2 parts of N,N′-methylenebisacrylamide and 120 parts of deionized water were mixed to obtain a premixed solution, then 20 parts of modified nano-silicon carbide and 6 parts of carbon fiber composite were added and ultrasonically dispersed evenly, and then 70 parts of micro-silicon carbide and 4 parts of sodium polyacrylate were added and stirred evenly to obtain a slurry. S2: The slurry was first injection-molded. By weight, 300 parts of the slurry, 4 parts of a 25% tetramethylethylenediamine solution and 16 parts of a 30% ammonium persulfate solution were stirred evenly, and then vacuum casting was carried out into the blade mold and left standing at room temperature for 40 min; freeze-dried, and then vacuum degreased (placed in an argon atmosphere, first heated to 200 °C at a rate of 5 °C / min, then heated to 700 °C at a rate of 1 °C / min, and finally heated to 900 °C at a rate of 2 °C / min and held for 60 min) to obtain a composite material blade. S3: The composite material blade was pretreated (first cleaned with anhydrous ethanol, and then sandblasted to make the surface roughness of the composite material blade 2.6 μm), and then the coating powder was flame sprayed (air flow rate was 100 L / min, propylene flow rate was 90 L / min, nitrogen flow rate was 40 L / min, hydrogen flow rate was 50 L / min, powder feeding rate was 130 g / min, cooling gas pressure was 0.5 MPa, spraying distance was 160 mm) on the composite material blade to form a composite coating, obtaining an aeroengine blade.

[0037] Preparation of the coating powder: By weight, 8 parts of chromium nitrate, 6 parts of lanthanum nitrate, and 3 parts of calcium nitrate are added to 200 parts of deionized water and dissolved thoroughly. Then, 8 parts of citric acid and 6 parts of ethylene glycol are added and stirred until dissolved. Next, 8 parts of commercially available nickel-chromium alloy powder are added for heat treatment. First, it is kept at 130 °C for 10 h, then at 800 °C for 2 h, cooled to room temperature, and pulverized to obtain modified nickel-chromium alloy powder. 30 parts of the modified nickel-chromium alloy powder, 30 parts of tungsten carbide powder, and 50 parts of chromium carbide powder are mixed and ball-milled to obtain the coating powder.

[0038] Preparation of the modified nano-silicon carbide: By weight, 4 parts of commercially available nano-silicon carbide I (product number S104653, particle size 40 nm) are dispersed in 300 parts of a polyethylene glycol solution with a mass fraction of 8% to obtain solution A. 3 parts of dopamine hydrochloride and 5 parts of tris(hydroxymethyl)aminomethane are dispersed in 2200 parts of deionized water to obtain solution B. 300 parts of solution A are added to 2200 parts of solution B, and then 0.8 part of nickel chloride hexahydrate is added for modification. The pH is adjusted to 8.8, and it is stirred at 40 °C for 10 h, centrifuged, washed with water, and freeze-dried to obtain the modified nano-silicon carbide.

[0039] Preparation of the carbon fiber composite material: First, commercially available carbon fiber is impregnated in acetone at 80 °C for 2 h, washed with water and dried. Then, it is heated in concentrated nitric acid at 80 °C for 2 h, washed with water, dried, and then immersed in a 3 mg / mL polyethyleneimine solution for 60 min and dried to obtain grafted carbon fiber. The grafted carbon fiber is added to a 4 mg / mL graphene oxide dispersion and impregnated for 4 h, and then vacuum-dried to obtain the carbon fiber composite material.

[0040] Example 2

[0041] This example provides a method for preparing an aero-engine blade, including the following steps: S1: By weight, 18 parts of acrylamide, 1 part of N,N′-methylenebisacrylamide, and 100 parts of deionized water are mixed to obtain a premixed solution. Then, 10 parts of the modified nano-silicon carbide and 4 parts of the carbon fiber composite material are added and ultrasonically dispersed evenly. Next, 60 parts of micron-sized silicon carbide and 2 parts of sodium polyacrylate are added and stirred evenly to obtain a slurry. S2: The slurry is first injection-molded. By weight, 200 parts of the slurry, 2 parts of a 25% tetramethylethylenediamine solution, and 12 parts of a 30% ammonium persulfate solution are stirred evenly, and then vacuum-poured into the blade mold and left standing at room temperature for 30 min. It is freeze-dried and then vacuum-degreased (placed in an argon atmosphere, first heated to 200 °C at a rate of 5 °C / min, then to 700 °C at a rate of 1 °C / min, and finally to 900 °C at a rate of 2 °C / min, and kept at this temperature for 50 min) to obtain a composite blade. S3: Pretreat the composite material blade (first clean it with absolute ethanol, and then perform sandblasting treatment to make the surface roughness of the composite material blade 2.4 μm), and then form a composite coating on the composite material blade by flame spraying (air flow rate is 90 L / min, propylene flow rate is 80 L / min, nitrogen flow rate is 35 L / min, hydrogen flow rate is 45 L / min, powder feeding rate is 120 g / min, cooling gas pressure is 0.3 MPa, spraying distance is 140 mm) to obtain an aeroengine blade.

[0042] Preparation of the coating powder: By weight, add 4 parts of chromium nitrate, 4 parts of lanthanum nitrate, and 1 part of calcium nitrate into 180 parts of deionized water and dissolve them fully. Then add 4 parts of citric acid and 2 parts of ethylene glycol and stir to dissolve. Then add 4 parts of commercially available nickel-chromium alloy powder and perform heat treatment. First, keep it at 120 °C for 12 h, then keep it at 700 °C for 4 h, cool to room temperature, and pulverize to obtain modified nickel-chromium alloy powder; Mix 20 parts of the modified nickel-chromium alloy powder, 20 parts of tungsten carbide powder, and 40 parts of chromium carbide powder and ball mill to obtain the coating powder.

[0043] Preparation of the modified nano-silicon carbide: By weight, disperse 2 parts of commercially available nano-silicon carbide I (product number S104653, particle size is 40 nm) in 200 parts of a 4% polyethylene glycol solution by mass to obtain solution A. Disperse 1 part of dopamine hydrochloride and 3 parts of tris(hydroxymethyl)aminomethane in 2000 parts of deionized water to obtain solution B. Add 200 parts of solution A to 2000 parts of solution B, then add 0.4 part of nickel chloride hexahydrate for modification treatment, adjust the pH to 8.4, stir at 35 °C for 12 h, centrifuge, wash with water, and freeze-dry to obtain the modified nano-silicon carbide.

[0044] Preparation of the carbon fiber composite material: First, immerse commercially available carbon fiber in acetone at 70 °C for 4 h, wash with water and dry. Then heat it in concentrated nitric acid at 75 °C for 3 h, wash with water, dry, and then immerse it in a 1 mg / mL polyethyleneimine solution for 60 min and dry to obtain grafted carbon fiber; Add the grafted carbon fiber to a 4 mg / mL graphene oxide dispersion and immerse it for 2 h, and dry it under vacuum to obtain the carbon fiber composite material.

[0045] Example 3

[0046] This example provides a method for preparing an aeroengine blade, including the following steps: S1: By weight, mix 21 parts of acrylamide, 1.5 parts of N,N′-methylenebisacrylamide, and 110 parts of deionized water to obtain a premixed solution. Then add 15 parts of the modified nano-silicon carbide and 5 parts of the carbon fiber composite material and disperse them evenly by ultrasonic treatment. Then add 65 parts of micron-sized silicon carbide and 3 parts of sodium polyacrylate and stir evenly to obtain a slurry; S2: The slurry is first injection molded, and 250 parts of the slurry, 3 parts of 25% by weight tetramethylethylenediamine solution and 14 parts of 30% by weight ammonium persulfate solution are mixed evenly, and then vacuum poured into the blade mold, and left to stand at room temperature for 35 minutes; freeze-dried, and then vacuum degreased (placed in an argon atmosphere, first heated to 200°C at a rate of 5°C / min, then heated to 700°C at a rate of 1°C / min, and finally heated to 900°C at a rate of 2°C / min, and kept warm for 55 minutes), to obtain a composite blade; S3: The composite blade is pre-treated (cleaned with anhydrous ethanol first, and then sandblasted to make the surface roughness of the composite blade 2.5μm), and then the coating powder is flame sprayed (air flow rate is 95L / min, propylene flow rate is 85L / min, nitrogen flow rate is 38L / min, hydrogen flow rate is 48L / min, powder delivery amount is 125g / min, cooling gas pressure is 0.4MPa, and spraying distance is 150mm) to form a composite coating on the composite blade to obtain an aircraft engine blade.

[0047] Preparation of the coating powder: in parts by weight, 6 parts of chromium nitrate, 5 parts of lanthanum nitrate and 2 parts of calcium nitrate are added to 190 parts of deionized water to fully dissolve, then 6 parts of citric acid and 4 parts of ethylene glycol are added and stirred to dissolve, and then 6 parts of commercially available nickel-chromium alloy powder are added for heating treatment, first at 125° C. for 11 hours, then at 750° C. for 3 hours, cooled to room temperature, and crushed to obtain modified nickel-chromium alloy powder; 25 parts of modified nickel-chromium alloy powder, 25 parts of tungsten carbide powder and 45 parts of chromium carbide powder are mixed and ball-milled to obtain coating powder.

[0048] Preparation of the modified nano silicon carbide: In parts by weight, 3 parts of commercially available nano silicon carbide I (article number S104653, particle size of 40 nm) are dispersed in 250 parts of a 6% polyethylene glycol solution to obtain liquid A, 2 parts of dopamine hydrochloride and 4 parts of tris(hydroxymethyl)aminomethane are dispersed in 2100 parts of deionized water to obtain liquid B, 250 parts of liquid A are added to 2100 parts of liquid B, and then 0.6 parts of nickel chloride hexahydrate are added for modification treatment, the pH is adjusted to 8.6, stirred at 38° C. for 11 hours, centrifuged, washed with water, and freeze-dried to obtain modified nano silicon carbide.

[0049] Preparation of the carbon fiber composite material: first, commercially available carbon fiber is immersed in acetone at 75° C. for 3 hours, washed with water and dried, then heated in concentrated nitric acid at 78° C. for 3 hours, washed with water, dried, and then immersed in a 2 mg / mL polyethyleneimine solution for 55 minutes, dried to obtain a grafted carbon fiber; the grafted carbon fiber is added to a 4 mg / mL graphene oxide dispersion and immersed for 3 hours, and vacuum dried to obtain a carbon fiber composite material.

[0050] Comparative Example 1 The difference between this comparative example and Example 1 is that commercially available nano - silicon carbide Ⅰ (product number S104653, particle size of 40 nm) is used to replace the modified nano - silicon carbide.

[0051] Comparative Example 2 The difference between this comparative example and Example 1 is that commercially available nano - silicon carbide Ⅱ (product number S121696, particle size of 700 nm) is used to replace commercially available nano - silicon carbide Ⅰ (product number S104653, particle size of 40 nm) for the preparation of modified nano - silicon carbide.

[0052] Comparative Example 3 The difference between this comparative example and Example 1 is that commercially available carbon fiber (model SYT45) is used to replace the carbon fiber composite material.

[0053] Comparative Example 4 The difference between this comparative example and Example 1 is that commercially available nickel - chromium alloy powder (product number R168690) is used to replace the modified nickel - chromium alloy powder for the preparation of the coating powder.

[0054] The performance of the aero - engine blades provided in the above - mentioned examples and comparative examples was tested, and the test method is as follows: (1) Test for anti - thermal - cold cycle performance: The air - cooling method was adopted. The cooling time of the test piece was not allowed to exceed 5 min, and the heating time of the test piece was not allowed to exceed 2 min.

[0055] (2) Test for erosion resistance: The medium was a 3.5% mass - fraction NaCl solution, the sand content was 3%, the erosion angle was 90°, the erosion speed was 10 m / s, and the erosion time was 24 h.

[0056] The above - mentioned performance test data are shown in Table 1.

[0057] Table 1 Performance Test Results

[0058] As can be seen from the above, in the present invention, by modifying the component nano - silicon carbide of the blade material, introducing the carbon fiber composite material for joint use, and forming a composite coating on the surface through spraying treatment, aero - engine blades (Examples 1 - 3) were prepared. The number of anti - thermal - cold cycles of them is 1378 - 1395 times, and the corrosion rate is 0.81 - 0.89 g / m 2 ·h.

[0059] Compared with Example 1, when using commercially available nano-silicon carbide Ⅰ (product number S104653, particle size of 40 nm) to replace the modified nano-silicon carbide, the number of thermal shock cycles decreases and the corrosion rate increases (Comparative Example 1); compared with Example 1, when using commercially available nano-silicon carbide Ⅱ (product number S121696, particle size of 700 nm) to replace commercially available nano-silicon carbide Ⅰ (product number S104653, particle size of 40 nm) for the preparation of modified nano-silicon carbide, due to the too large particle size of commercially available nano-silicon carbide Ⅱ, the modification effect is poor, the number of thermal shock cycles decreases and the corrosion rate increases (Comparative Example 2); compared with Example 1, when using commercially available carbon fiber (model SYT45) to replace the carbon fiber composite material, the number of thermal shock cycles decreases and the corrosion rate increases (Comparative Example 3); compared with Example 1, when using commercially available nickel-chromium alloy powder (product number R168690) to replace the modified nickel-chromium alloy powder for the preparation of the coating powder, the number of thermal shock cycles decreases and the corrosion rate increases (Comparative Example 4).

[0060] In summary, the present invention modifies the component nano-silicon carbide of the blade material, simultaneously introduces and uses the carbon fiber composite material, and forms a composite coating on the surface through spraying treatment to prepare an aero-engine blade, effectively improving the thermal shock resistance performance and simultaneously obtaining good erosion resistance performance.

Claims

1. A method for preparing an aeroengine blade, characterized in that: The following steps are involved: S1: In parts by weight, 18-24 parts of acrylamide, 1-2 parts of N,N′-methylenebisacrylamide and 100-120 parts of deionized water are mixed to obtain a premixed solution, and then 10-20 parts of nano silicon carbide and 4-6 parts of carbon fiber are added and ultrasonically dispersed uniformly, and then 60-70 parts of micro silicon carbide and 2-4 parts of sodium polyacrylate are added and stirred uniformly to obtain a slurry; S2: injection molding the slurry, freeze drying and vacuum degreasing to obtain a composite blade; S3: pre-treating the composite blade, and then flame-spraying the coating powder on the composite blade to form a composite coating, thereby obtaining an aeroengine blade; The preparation method of the coating powder comprises: adding 4 to 8 parts of chromium nitrate, 4 to 6 parts of lanthanum nitrate and 1 to 3 parts of calcium nitrate to 180 to 200 parts of deionized water by weight to fully dissolve, then adding 4 to 8 parts of citric acid and 2 to 6 parts of ethylene glycol to stir and dissolve, and then adding 4 to 8 parts of commercially available nickel-chromium alloy powder to perform a temperature treatment to obtain a modified nickel-chromium alloy powder; and mixing and ball-milling 20 to 30 parts of the modified nickel-chromium alloy powder, 20 to 30 parts of tungsten carbide powder and 40 to 50 parts of chromium carbide powder to obtain a coating powder.

2. The method for preparing an aeroengine blade according to claim 1, characterized in that: The nano silicon carbide is modified nano silicon carbide; The preparation method of the modified nano silicon carbide comprises: dispersing 2-4 parts of commercially available nano silicon carbide in 200-300 parts of a polyethylene glycol solution with a mass fraction of 4-8% to obtain a liquid A, dispersing 1-3 parts of dopamine hydrochloride and 3-5 parts of tris(hydroxymethyl)aminomethane in 2000-2200 parts of deionized water to obtain a liquid B, adding 200-300 parts of the liquid A to 2000-2200 parts of the liquid B, and then adding 0.4-0.8 parts of nickel chloride hexahydrate for modification to obtain the modified nano silicon carbide.

3. The method for preparing an aeroengine blade according to claim 2, characterized in that: The modification treatment conditions include: adjusting the pH to 8.4-8.8, stirring at 35-40° C. for 10-12 hours, centrifuging, washing with water, and freeze-drying.

4. The method for preparing an aeroengine blade according to claim 2, characterized in that: The particle size of the commercially available nano-silicon carbide is 20-100 nm.

5. The method for preparing an aeroengine blade according to claim 1, characterized in that: The carbon fiber is a carbon fiber composite material; The preparation method of the carbon fiber composite material comprises: firstly performing surface pretreatment on commercially available carbon fibers, then immersing the carbon fibers in a 1-3 mg / mL polyethyleneimine solution for 50-60 minutes, and drying the solution to obtain grafted carbon fibers; The grafted carbon fiber was added into a 4 mg / mL graphene oxide dispersion and immersed for 2-4 h, and then vacuum dried to obtain a carbon fiber composite material.

6. The method for preparing an aeroengine blade according to claim 5, characterized in that: The surface pretreatment conditions include: first immersing the commercially available carbon fiber in acetone at 70-80° C. for 2-4 hours, washing with water and drying, then heating in concentrated nitric acid at 75-80° C. for 2-3 hours, washing with water, and drying.

7. The method for preparing an aeroengine blade according to claim 1, characterized in that: The conditions of the temperature treatment include: first keeping the temperature at 120-130° C. for 10-12 hours, then keeping the temperature at 700-800° C. for 2-4 hours, cooling to room temperature, and crushing.

8. The method for preparing an aeroengine blade according to claim 1, characterized in that: The flame spraying conditions include: air flow rate of 90-100 L / min, propylene flow rate of 80-90 L / min, nitrogen flow rate of 35-40 L / min, hydrogen flow rate of 45-50 L / min, powder feeding amount of 120-130 g / min, cooling gas pressure of 0.3-0.5 MPa, and spraying distance of 140-160 mm.

9. The method for preparing an aeroengine blade according to claim 1, characterized in that: The pre-treatment conditions include: first cleaning with anhydrous ethanol, and then sandblasting, so that the surface roughness of the composite blade is 2.4-2.6 μm.

10. An aeroengine blade, characterized in that: The method is obtained by the preparation method according to any one of claims 1 to 9.

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