Preparation method of anti-ablation coating of composite material blade of hydrogen-fired gas turbine

Abstract

The invention belongs to the field of inorganic non-metallic materials, and particularly relates to a preparation method of an anti-ablation coating for a composite material blade of a hydrogen-burning gas turbine, the anti-ablation coating is coated on a gas runner surface of a ceramic matrix composite material blade, and the anti-ablation coating is composed of a packaging layer, a chemical barrier layer, a water-oxygen-resistant layer and a heat insulation layer from inside to outside in sequence, the anti-ablation coating is prepared by adopting a composite technology of slurry dipping, plasma spraying and vibration finishing treatment, and the protection requirement of the ceramic matrix composite blade in a 1600 DEG C hydrogen combustion environment can be met. The preparation method of the anti-ablation coating of the composite material blade of the hydrogen gas turbine has the advantages of convenience in construction, excellent aerodynamic characteristics, good hydrogen ablation resistance and CMAS corrosion resistance, long service life and the like.

Description

Technical Field

[0001] The invention belongs to the field of inorganic non-metallic materials, and in particular relates to a method for preparing an anti-ablation coating of a composite material blade of a hydrogen-fired gas turbine. Background Art

[0002] Under the background of the "dual carbon" emission reduction goals, hydrogen as a clean and sustainable energy carrier has received widespread attention. Among them, hydrogen-fired gas turbines with the advantages of zero carbon emissions, flexible controllability, etc. will replace traditional gas turbines and become the inevitable choice for achieving the "dual carbon" emission reduction goals in the energy field. Hydrogen-fired gas turbines are a kind of power equipment that uses rich hydrogen as fuel and pure oxygen as oxidant. It directly burns to generate high-temperature and high-pressure water vapor (1750°C), which is then directly introduced into the turbine to work. Its thermal efficiency can reach more than 70%. However, high-temperature and high-pressure water vapor up to 1750°C directly acts on the turbine blade components, which places extremely high demands on the temperature bearing capacity and durability of the turbine components.

[0003] Silicon carbide ceramic matrix composites (SiC-CMCs) have low density (about 1 / 3 of high-temperature alloys), high specific strength, insensitivity to cracks, high temperature resistance and chemical corrosion resistance, and are one of the most promising structural materials to replace high-temperature alloys in the future. However, in the service environment of hydrogen-fired gas turbines fueled by hydrogen, combustion produces a large amount of water vapor and excess oxygen that react with SiC under high temperature conditions to generate volatile Si(OH)4, resulting in rapid consumption of the matrix material. This is currently limiting the development of SiC f One of the main reasons for the application of SiC materials. In particular, SiC f / SiC composite blade components are subjected to high temperature hydrogen fuel ablation above 1750℃ during operation, and the large amount of water vapor produced by the blade produces water-oxygen coupling corrosion damage, which is the cause of SiC f The main factor for premature failure of / SiC composite blades. It is urgent to develop a protective coating material and its preparation method that has the composite functions of high temperature ablation resistance and water-oxygen corrosion resistance. Summary of the invention

[0004] In order to solve the needs of the prior art, the present invention aims to provide a method for preparing an anti-ablation coating for a composite blade of a hydrogen-fired gas turbine.

[0005] The technical solution of the present invention:

[0006] A method for preparing an anti-ablation coating for a composite blade of a hydrogen-fired gas turbine, wherein the anti-ablation coating is coated on a SiC fThe gas flow path surface of the / SiC composite blade is composed of an encapsulation layer, a chemical barrier layer, a water and oxygen resistant layer and a heat insulation layer from the inside to the outside. The anti-ablation coating is prepared by slurry impregnation and plasma spraying composite technology. The specific preparation process includes the following steps:

[0007] Step 1: Pretreatment of the substrate surface: Use a high temperature resistant shield to protect the non-gas flow path surface of the SiCf / SiC composite blade, use acetone to clean the gas flow path surface of the SiCf / SiC composite blade, and use a high energy beam to roughen the gas flow path surface after drying to obtain a gas flow path surface with a surface roughness not less than Ra3.2 and a reaction layer depth of ≤5μm;

[0008] Step 2: Matrix packaging: distilled water, Si powder with a particle size of 1 μm to 10 μm, TiC powder with a particle size of 1 μm to 10 μm, and HfB2 powder with a particle size of 1 μm to 10 μm are mixed and ball-milled for 8 to 24 hours in a mass ratio of 100:50:10:5 to prepare a slurry, and the SiCf / SiC composite blade is immersed in the slurry for penetration for 10 to 50 minutes; the infiltrated SiCf / SiC composite blade is placed in a protective atmosphere furnace at 1400°C to 1600°C for high-temperature sintering treatment, and the sintered SiCf / SiC composite blade is surface polished with a diamond abrasive belt to remove residual sintering residues;

[0009] Step 3: Prepare the gas flow path surface coating by plasma spraying technology: spray the gas flow path surface of the SiCf / SiC composite blade treated in step 1 and step 2 with a chemical barrier layer, a water and oxygen resistant layer and a heat insulation layer in sequence, wherein the chemical barrier layer is composed of RESiO4 with a thickness of 100 μm to 150 μm; the water and oxygen resistant layer is composed of rare earth monosilicate RE2SiO5 with a thickness of 100 μm to 150 μm; the heat insulation layer is composed of Al2O3, SiO2 and HfO2 with a thickness of 100 μm to 150 μm; the surface temperature of the substrate is controlled at 600 to 800°C during the spraying process, and the interface strength between the coating and the substrate is ≥15 MPa;

[0010] Step 4: Vibration finishing treatment: SiC particles are used as abrasives and vibration finishing technology is used to polish the gas flow channel surface coating. The surface finish of the coating after polishing is not less than Ra1.6μm;

[0011] Step 5: stress relief treatment: remove the shielding on the non-gas flow path surface, place the coated SiCf / SiC composite blade in a protective atmosphere furnace for stress relief treatment, and the stress relief treatment temperature is 600-1500°C.

[0012] The high-energy beam texturing treatment technology in step 1 adopts a femtosecond laser or a plasma jet.

[0013] The chemical barrier layer is HfSiO4 or ZrSiO4 or a modified product thereof.

[0014] The water- and oxygen-resistant layer is one of Yb2SiO5, Lu2SiO5, Sc2SiO5 or one of Yb2SiO5 and its modified products.

[0015] The heat insulation layer is composed of Al2O3, SiO2 and cubic structure HfO2, wherein the molar ratio of the three components is (10-30) %: (10-30) %; (40-80) %.

[0016] The cubic structure HfO2 is modified by adding one of the elements Y, Yb and Gd.

[0017] The plasma spraying technology is atmospheric plasma spraying or vacuum plasma spraying, and the spraying power is 30-90kW.

[0018] The SiCf / SiC composite material blade is prepared by adopting one of the MI process, the PIP process or the CVI process.

[0019] Beneficial effects of the present invention:

[0020] 1) In the present invention, SiC f In order to solve the problems of pores, fiber exposure and reduced mechanical properties in the process of blade forming of SiC composite materials, a packaging material composed of Si, TiC and HfB2 was proposed. The slurry impregnation process was used to f / SiC composite blades are encapsulated. This material has the advantages of strong penetration ability, good wettability and thermal matching with the matrix, which can effectively solve the problem of SiC f / SiC composite blade molding process, the problem of pores and exposed fibers. By adding TiC and HfB2, hafnium silicate is formed during long-term high-temperature service, which has excellent chemical compatibility and thermal matching with the RESiO4 chemical barrier layer, and can further improve the heat resistance and high-temperature stability of the encapsulation layer, solving the problem of low melting point (1410℃) and easy volatility of the traditional silicon bonding layer.

[0021] 2) The RESiO4 chemical barrier layer and RE2SiO5 rare earth monosilicate environmental barrier layer were prepared in sequence by plasma spraying technology. The RESiO4 layer has a high melting point (~1750℃) and a low thermal expansion coefficient (3.6~4.0×10 -6 / K) and low oxygen diffusion rate, which can significantly reduce the high-temperature oxidation rate of the encapsulation layer and the SiC substrate and improve the interface stability of the coating; the RE2SiO5 layer has extremely low silicon dioxide activity and good resistance to CMAS corrosion, which can significantly reduce the corrosion effect of hydrogen atmosphere on the substrate; the cubic structure HfO2 thermal insulation layer has the advantages of high melting point (~2800℃) and low thermal conductivity (≤1.0W / m·K), which can significantly improve the temperature bearing capacity and thermal insulation performance of the coating, and meet the composite functions of ultra-high temperature service above 1600℃ and resistance to ablation in hydrogen atmosphere.

[0022] 3) The composite process of high-energy beam, plasma spraying and vibration finishing can prepare the composite functional coating on the surface of complex blades to resist hydrogen atmosphere ablation and CMAS corrosion, which has the advantages of short process cycle, low cost and strong controllability. The surface roughness of the coating reaches Ra1.6μm, which can significantly improve the aerodynamic characteristics and CMAS corrosion resistance of the ceramic matrix composite blade surface. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the examples. It should be understood that the preparation methods described in the examples of the present invention are only used to illustrate the present invention, rather than to limit the present invention, and simple improvements to the preparation methods of the present invention under the premise of the concept of the present invention belong to the scope of protection claimed in the present invention.

[0024] A method for preparing an anti-ablation coating for a composite blade of a hydrogen-fired gas turbine, wherein the anti-ablation coating is coated on a SiC f The gas flow channel surface of the / SiC composite blade is composed of an encapsulation layer, a chemical barrier layer, a water and oxygen resistant layer and a heat insulation layer from the inside to the outside. The anti-ablation coating is prepared by slurry impregnation and plasma spraying composite technology. The chemical barrier layer is one of HfSiO4 or ZrSiO4 or their modified products. The water and oxygen resistant layer is one of Yb2SiO5, Lu2SiO5, Sc2SiO5 or one of Yb2SiO5 and their modified products. The heat insulation layer is composed of Al2O3, SiO2 and cubic structure HfO2, wherein the molar ratio of the three components is (10-30)%: (10-30)%; (40-80)%.

[0025] The specific preparation process includes the following steps:

[0026] Step 1: Pretreatment of the substrate surface: Use a high-temperature resistant shield to protect the non-gas flow path surface of the SiCf / SiC composite blade, use acetone to clean the gas flow path surface of the SiCf / SiC composite blade, and use a high-energy beam to roughen the gas flow path surface after drying to obtain a gas flow path surface with a surface roughness not less than Ra3.2 and a reaction layer depth of ≤5μm; the high-energy beam roughening treatment technology uses a femtosecond laser or a plasma jet.

[0027] Step 2: Matrix packaging: distilled water, Si powder with a particle size of 1 μm to 10 μm, TiC powder with a particle size of 1 μm to 10 μm, and HfB2 powder with a particle size of 1 μm to 10 μm are mixed and ball-milled for 8 to 24 hours in a mass ratio of 100:50:10:5 to prepare a slurry, and the SiCf / SiC composite blade is immersed in the slurry for penetration for 10 to 50 minutes; the infiltrated SiCf / SiC composite blade is placed in a protective atmosphere furnace at 1400°C to 1600°C for high-temperature sintering treatment, and the sintered SiCf / SiC composite blade is surface polished with a diamond abrasive belt to remove residual sintering residues;

[0028] Step 3 uses plasma spraying technology to prepare the gas flow channel surface coating: the gas flow channel surface of the SiCf / SiC composite blade treated in step 1 and step 2 is sprayed with a chemical barrier layer, a water and oxygen resistant layer and a heat insulation layer in sequence, wherein the chemical barrier layer is composed of RESiO4, with a thickness of 100μm to 150μm; the water and oxygen resistant layer is composed of rare earth monosilicate RE2SiO5, with a thickness of 100μm to 150μm; the heat insulation layer is composed of Al2O3, SiO2 and HfO2, with a thickness of 100μm to 150μm; the surface temperature of the substrate is controlled at 600 to 800℃ during the spraying process, and the interface strength between the coating and the substrate is ≥15MPa; the cubic structure HfO2 is modified by adding one of the elements Y, Yb and Gd. The plasma spraying technology is atmospheric plasma spraying or vacuum plasma spraying, and the spraying power is 30 to 90kW.

[0029] Step 4: Vibration finishing treatment: SiC particles are used as abrasives and vibration finishing technology is used to polish the gas flow channel surface coating. The surface finish of the coating after polishing is not less than Ra1.6μm;

[0030] Step 5: stress relief treatment: remove the shielding on the non-gas flow path surface, place the coated SiCf / SiC composite blade in a protective atmosphere furnace for stress relief treatment, and the stress relief treatment temperature is 600-1500°C.

[0031] The SiCf / SiC composite material blade is prepared by adopting one of the MI process, the PIP process or the CVI process.

[0032] Example 1

[0033] Typical hydrogen-fired gas turbine guide vane components, the base material is PIP process SiC f / SiC composite material. The surface of the component was ultrasonically cleaned with acetone, and after the surface was dried with compressed air, it was placed in a resistance furnace for drying.

[0034] Substrate surface pretreatment: Use high temperature resistant shielding to treat SiC f / SiC composite blade non-gas flow path surface protection, acetone cleaning SiC f / SiC composite blade gas flow path surface, after drying, is roughened using a femtosecond laser beam to obtain a surface roughness Ra of 3.2μm and a reaction layer depth of 2μm. The laser beam parameters used are: laser frequency 1.0MHZ, pulse width 10 microseconds, and scanning speed 400mm / second.

[0035] Matrix encapsulation: Distilled water, Si powder with a particle size of 1 μm, TiC powder with a particle size of 1 μm, and HfB2 powder with a particle size of 1 μm were mixed and ball-milled for 12 hours in a mass ratio of 100:50:10:5 to prepare a slurry, and the composite blade was immersed in the slurry for penetration for 30 minutes. The infiltrated blade was placed in a protective atmosphere furnace at 1500°C for high-temperature sintering, and the sintered blade was surface polished with a diamond abrasive belt to remove the residual sintering residue.

[0036] Plasma spraying: Plasma spraying technology is used on SiC f The gas flow path surface of the / SiC composite blade is sprayed with a chemical barrier layer, a water and oxygen resistant layer, and a thermal insulation layer in sequence, wherein the chemical barrier layer is composed of HfSiO4 with a thickness of 125μm; the water and oxygen resistant layer is composed of rare earth monosilicate Yb2SiO5 with a thickness of 125μm; the thermal insulation layer is composed of Al2O3, SiO2 and HfO2 with a thickness of 150μm. The atmospheric plasma spraying parameters used are: power 55kW, argon flow rate 50NLPM, powder feeding speed 10g / min, and spraying distance 150mm. The surface temperature of the substrate is controlled at 700℃ during the spraying process, and the interface strength between the coating and the substrate can reach 19.2MPa;

[0037] Vibration finishing: SiC particles are used as abrasives and vibration finishing technology is used to polish the gas flow channel surface coating. The abrasive size is 200 mesh. The main parameters are: frequency is 50Hz; the total surface finishing time is 20min. The surface finish of the foamed coating is Ra1.6μm.

[0038] Stress relief treatment: Remove the shielding on the non-gas flow channel surface and replace the coated SiC f The SiC composite blade is placed in a protective atmosphere furnace for stress relief treatment at a temperature of 1300°C.

[0039] The typical properties of the obtained anti-ablation coating for hydrogen-fired gas turbine composite blades are as follows:

[0040]

[0041] Example 2

[0042] Typical hydrogen-fired gas turbine guide vane components, the matrix material is SiC through melt infiltration process f / SiC composite material. The surface of the component was ultrasonically cleaned with acetone, and after the surface was dried with compressed air, it was placed in a resistance furnace for drying.

[0043] Substrate surface pretreatment: Use high temperature resistant shielding to treat SiC f / SiC composite blade non-gas flow path surface protection, acetone cleaning SiC f / SiC composite blade gas flow path surface, after drying, plasma jet is used to roughen the gas flow path surface, and the surface roughness Ra is 3.2μm, the reaction layer depth is 5μm, and the plasma jet parameters used are: plasma power 90kW, scanning speed 400mm / second. .

[0044] Matrix encapsulation: Distilled water, Si powder with a particle size of 5 μm, TiC powder with a particle size of 1 μm, and HfB2 powder with a particle size of 1 μm were mixed and ball-milled for 12 hours in a mass ratio of 100:50:10:5 to prepare a slurry, and the composite blade was immersed in the slurry for penetration for 50 minutes. The infiltrated blade was placed in a protective atmosphere furnace at 1500°C for high-temperature sintering, and the surface of the sintered blade was polished with a diamond belt to remove the residual sintering residue.

[0045] Plasma spraying: Plasma spraying technology is used on SiC f The gas flow path surface of the / SiC composite blade is sprayed with a chemical barrier layer, a water and oxygen resistant layer, and a thermal insulation layer in sequence, wherein the chemical barrier layer is composed of ZrSiO4 with a thickness of 100μm; the water and oxygen resistant layer is composed of rare earth monosilicate Lu2SiO5 with a thickness of 100μm; the thermal insulation layer is composed of Al2O3, SiO2 and HfO2 with a thickness of 100μm. The atmospheric plasma spraying parameters used are: power 65kW, argon flow 55NLPM, powder feeding speed 10g / min, spraying distance 150mm. The surface temperature of the substrate is controlled at 800℃ during the spraying process, and the interface strength between the coating and the substrate can reach 20.6MPa;

[0046] Vibration finishing: SiC particles are used as abrasives and vibration finishing technology is used to polish the gas flow channel surface coating. The abrasive size is 200 mesh. The main parameters are: frequency is 50Hz; the total surface finishing time is 20min. The surface finish of the foamed coating is Ra1.6μm.

[0047] Stress relief treatment: Remove the shielding on the non-gas flow channel surface and replace the coated SiC f The SiC composite blade is placed in a protective atmosphere furnace for stress relief treatment at a temperature of 1300°C.

[0048] The typical properties of the obtained anti-ablation coating for hydrogen-fired gas turbine composite blades are as follows:

[0049]

Claims

1. A method for preparing an anti-ablation coating for a composite blade of a hydrogen-fired gas turbine, characterized in that: The anti-ablation coating is coated on SiC f The gas flow path surface of the / SiC composite blade is composed of an encapsulation layer, a chemical barrier layer, a water and oxygen resistant layer and a heat insulation layer from the inside to the outside. The anti-ablation coating is prepared by slurry impregnation and plasma spraying composite technology. The specific preparation process includes the following steps: Step 1: Pretreatment of the substrate surface: Use a high temperature resistant shield to protect the non-gas flow path surface of the SiCf / SiC composite blade, use acetone to clean the gas flow path surface of the SiCf / SiC composite blade, and use a high energy beam to roughen the gas flow path surface after drying to obtain a gas flow path surface with a surface roughness not less than Ra3.2 and a reaction layer depth of ≤5μm; Step 2: Matrix packaging: distilled water, Si powder with a particle size of 1 μm to 10 μm, TiC powder with a particle size of 1 μm to 10 μm, and HfB2 powder with a particle size of 1 μm to 10 μm are mixed and ball-milled for 8 to 24 hours in a mass ratio of 100:50:10:5 to prepare a slurry, and the SiCf / SiC composite blade is immersed in the slurry for penetration for 10 to 50 minutes; the infiltrated SiCf / SiC composite blade is placed in a protective atmosphere furnace at 1400°C to 1600°C for high-temperature sintering treatment, and the sintered SiCf / SiC composite blade is surface polished with a diamond abrasive belt to remove residual sintering residues; Step 3: Prepare the gas flow path surface coating by plasma spraying technology: spray the gas flow path surface of the SiCf / SiC composite blade treated in step 1 and step 2 with a chemical barrier layer, a water and oxygen resistant layer and a heat insulation layer in sequence, wherein the chemical barrier layer is composed of RESiO4 with a thickness of 100 μm to 150 μm; the water and oxygen resistant layer is composed of rare earth monosilicate RE2SiO5 with a thickness of 100 μm to 150 μm; the heat insulation layer is composed of Al2O3, SiO2 and HfO2 with a thickness of 100 μm to 150 μm; the surface temperature of the substrate is controlled at 600 to 800°C during the spraying process, and the interface strength between the coating and the substrate is ≥15 MPa; Step 4: Vibration finishing treatment: SiC particles are used as abrasives and vibration finishing technology is used to polish the gas flow channel surface coating. The surface finish of the coating after polishing is not less than Ra1.6μm; Step 5: stress relief treatment: remove the shielding on the non-gas flow path surface, place the coated SiCf / SiC composite blade in a protective atmosphere furnace for stress relief treatment, and the stress relief treatment temperature is 600-1500°C.

2. The method for preparing the anti-ablation coating of the composite material blade of hydrogen-fired gas turbine according to claim 1, characterized in that: Step 1: High energy beam texturing technology, using femtosecond laser or plasma jet.

3. The method for preparing the anti-ablation coating of the composite material blade of hydrogen-fired gas turbine according to claim 1, characterized in that: The chemical barrier layer is HfSiO4 or ZrSiO4 or a modified product thereof.

4. The method for preparing the anti-ablation coating of the composite material blade of hydrogen-fired gas turbine according to claim 1, characterized in that: The water- and oxygen-resistant layer is one of Yb2SiO5, Lu2SiO5, Sc2SiO5 or one of Yb2SiO5 and its modified products.

5. The method for preparing the anti-ablation coating of the composite material blade of hydrogen-fired gas turbine according to claim 1, characterized in that: The heat insulation layer is composed of Al2O3, SiO2 and cubic structure HfO2, wherein the molar ratio of the three components is (10-30) %: (10-30) %; (40-80) %.

6. The method for preparing the anti-ablation coating of the composite material blade of hydrogen-fired gas turbine according to claim 1, characterized in that: The cubic structure HfO2 is modified by adding one of the elements Y, Yb and Gd.

7. The method for preparing the anti-ablation coating of the composite material blade of hydrogen-fired gas turbine according to claim 1, characterized in that: The plasma spraying technology is atmospheric plasma spraying or vacuum plasma spraying, and the spraying power is 30-90kW.

8. The method for preparing the anti-ablation coating of the composite material blade of hydrogen-fired gas turbine according to claim 1, characterized in that: The SiCf / SiC composite material blade is prepared by adopting one of the MI process, the PIP process or the CVI process.

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