Multi-layer structure thermal protection coating suitable for hydrogen fuel gas turbine and preparation method of multi-layer structure thermal protection coating

Abstract

The invention discloses a multi-layer structure thermal protection coating suitable for a hydrogen fuel gas turbine and a preparation method of the multi-layer structure thermal protection coating. According to the multi-layer structure thermal protection coating, a high-temperature alloy serves as a base body, and a bonding bottom layer, a YSZ middle layer, a silicate and YSZ function transition layer and a silicate top layer are sequentially sprayed on the surface of the base body. The reliability and long service life of the YSZ coating and the water and oxygen corrosion resistance of the silicate material are comprehensively utilized, the disadvantage that the thermal expansion coefficients of the two materials are not matched is solved, the functional transition layer with the adjustable component proportion is added into the coating structure to relieve thermal mismatch, the water and oxygen corrosion resistance of the coating is improved, and then the overall service life of the coating is prolonged. The ceramic coating with the three-layer structure, namely the top layer silicate, the functional transition layer silicate + YSZ and the YSZ middle layer, is constructed, and the metal bonding layer is used below the ceramic coating, so that the preparation period of the coating is short, the reliability of the coating is high, and the service life of the high-temperature alloy of the hot end part of the hydrogen fuel gas turbine can be guaranteed.

Description

Technical Field

[0001] The invention relates to a high-temperature thermal protective coating and a preparation method thereof, and in particular to a multi-layered thermal protective coating suitable for a hydrogen fuel gas turbine and a preparation method thereof. Background Art

[0002] Hydrogen fuel gas turbines refer to gas turbines that use hydrogen as fuel. This technology is one of the important ways to achieve energy transformation and carbon neutrality. Using hydrogen instead of traditional natural gas as fuel can bring many advantages: the product of hydrogen combustion is mainly water vapor, and almost no CO is produced. 2 Greenhouse gases such as hydrogen can help reduce greenhouse gas emissions and combat climate change; hydrogen has a high energy density and can provide higher power output; compared with traditional fossil fuels such as natural gas, hydrogen fuel has extremely low pollutant emissions during combustion, which helps improve air quality; the application of hydrogen fuel gas turbines can promote the development of the hydrogen energy industry chain, including hydrogen production, storage, transportation and application. At the same time, studies have shown that under adiabatic and complete combustion conditions, the flame temperature of hydrogen fuel is nearly 300°C higher than that of natural gas, which can effectively increase the turbine inlet temperature of the gas turbine. In December 2023, the 30MW pure hydrogen gas turbine independently developed by Mingyang Hydrogen Power Technology Co., Ltd. was officially launched, which is of great significance to my country's realization of the development of hydrogen fuel gas turbines and the achievement of carbon neutrality goals.

[0003] However, traditional gas turbines are not designed to burn hydrogen, so the materials of components such as the combustion chamber and gas turbine need to be modified and upgraded to adapt to the combustion characteristics of hydrogen. The combustion chamber and turbine, as key components that determine the life of the gas turbine, not only have high operating temperatures, but also withstand the thermal shock caused by drastic temperature changes when the gas turbine is started and shut down. More importantly, when hydrogen fuel is used for combustion, the water vapor content in the combustion chamber will increase by about 160%, which not only puts forward the requirements for the materials of the hot end components to resist high temperature and thermal shock, but also puts forward the requirements for high temperature water oxygen corrosion. In order to ensure sufficient life, the parts with the worst working conditions in these two major components, such as the flame tube and blades, not only need to be made of high-temperature materials such as nickel-based and cobalt-based alloys, but also rely on air film cooling technology and thermal protection coating technology to reduce the operating temperature and resist environmental corrosion. Among them, the presence of water vapor actually accelerates the oxidation process of the alloy matrix. This catalytic effect poses a threat to the long-term performance and reliability of the hot end components because rapid oxidation shortens the service life of the material. Considering the differences in the service environment of gas turbines, the stability of the existing thermal protection coating material - yttrium-stabilized zirconia (YSZ) and the substrate material at higher temperatures and water vapor content should be considered. However, the existing YSZ coating is prone to stratification and degradation in high-temperature water vapor environments. It is urgent to develop a more stable thermal protection coating that can resist high-temperature water-oxygen corrosion.

[0004] Superimposing a silicate material - Yb with excellent resistance to water and oxygen corrosion 2 SiO 5 onto the thermal barrier coating YSZ used for the hot - end components of a hydrogen - fueled gas turbine is undoubtedly a quick and easily - obtainable method to address the above - mentioned challenges. However, Yb 2 SiO 5 (thermal expansion coefficient ∼ 7 - 8×10 -6 K -1 ) does not match the thermal expansion coefficient of YSZ (thermal expansion coefficient ∼ 11×10 -6 K -1 ). During actual service, it is difficult to withstand multiple thermal cycles, inevitably generating thermal mismatch stresses, which lead to the initiation of cracks within the coating until the coating spalls and fails. In addition, at temperatures above 1200 °C, due to the phase transformation of YSZ from the metastable tetragonal phase (t') to the cubic phase (c) during sintering and heating, and the phase transformation from t' to the monoclinic phase (m) during cooling, the YSZ coating causes a 3 - 5% volume expansion, accelerating the coating failure. Therefore, the silicate top layer also needs to play a part in heat insulation. Summary of the Invention

[0005] In order to ensure the durability of the multi-layered thermal protection coating applicable to hydrogen fuel gas turbines in a high-temperature water-oxygen corrosion environment, in view of the defects of the existing YSZ coating and the operating environment of hydrogen fuel gas turbines, the present invention provides a multi-layered thermal protection coating applicable to hydrogen fuel gas turbines and its preparation method. This new type of structured coating can be applied to pure hydrogen fuel gas turbines. The present invention comprehensively utilizes the reliability and long service life of the YSZ coating and the water-oxygen corrosion resistance of silicate materials, solves the disadvantage of the mismatched thermal expansion coefficients of the two materials, and adds a functional transition layer with adjustable composition ratio to the coating structure to relieve thermal mismatch and improve the water-oxygen corrosion resistance of the coating, thereby enhancing the overall service life of the coating. The present invention constructs a three-layer ceramic coating structure of a top-layer silicate, a functional transition layer of silicate + YSZ, and a YSZ intermediate layer, and uses a metal bonding layer under the ceramic coating. The coating preparation cycle is short and the coating reliability is high, which can ensure the service life of the superalloy of the hot-end components of hydrogen fuel gas turbines. The silicate top layer of the multi-layered thermal protection coating of the present invention is dense, with fewer defects such as pores and microcracks, and also undertakes partial heat insulation function while effectively resisting water-oxygen corrosion: in the remaining unmelted area of the top layer, the presence of micropores significantly increases the surface free energy of this area, promotes the densification process of the unmelted area, and peels off from the layered structure formed during the spraying process, ultimately resulting in the formation of larger-sized pores. To a certain extent, these macroscopic pores help offset the performance degradation caused by the micropore healing phenomenon of the coating in a high-temperature service environment and maintain the overall structural and functional stability of the coating; the functional transition layer is silicate + YSZ, controlling the proportion of silicate to be greater than that of YSZ. In this way, while relieving thermal mismatch in the transition layer, it also has the function of resisting water-oxygen corrosion. Adding a certain proportion of YSZ to the silicate coating can reduce the residual stress generated during the shrinkage process of the coating and reduce the internal thermal stress, thereby improving the thermal cycle life. Controlling the proportion of silicate to be greater than that of YSZ can effectively ensure the overall water-oxygen corrosion resistance of the coating. According to the actual requirements of the superalloy for hydrogen fuel gas turbines for the thermal protection coating, the proportion is adjusted to more specifically protect the alloy matrix from environmental corrosion, ensure the service life of the superalloy of the hot-end components of hydrogen fuel gas turbines, maintain the stability of the operation of the entire system, and provide strong technical support for the hydrogen energy power systems of power generation, marine ships, and military equipment.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] A multi-layered thermal protection coating applicable to hydrogen fuel gas turbines, with a superalloy as the substrate, and successively spraying a bonding bottom layer, a YSZ intermediate layer, a silicate + YSZ functional transition layer, and a silicate top layer on the surface of the substrate, wherein:

[0008] The diameter of the superalloy substrate is 25.4 mm, and the thickness is 3 - 20 mm, which is one or more of nickel-based superalloys and cobalt-based superalloys;

[0009] The material of the bond coat is MCrAlY, such as one or more of NiCrAlYCe, NiCrAlYSi, and CoCrAlYCe, with a thickness of 100 - 130 μm, which is used to improve the thermal compatibility between the ceramic coating and the metal substrate;

[0010] The material of the YSZ intermediate layer is YSZ, with a thickness of 130 - 150 μm, which is used to reduce the coating thermal conductivity, improve phase stability, and corrosion resistance;

[0011] The material of the silicate + YSZ functional transition layer is a premix of silicate and YSZ, with a thickness of 30 - 50 μm; among which the mass ratio of silicate is 51 - 99%, the structure and composition of silicate are the same as those of the material used for the silicate top layer, and the structure and composition of YSZ are the same as those of the material used for the YSZ intermediate layer, which is used to alleviate the thermal mismatch caused by different thermal expansion coefficients of different materials and improve the water and oxygen corrosion resistance of the coating;

[0012] The material of the silicate top layer is Yb 2 SiO 5 , with a thickness of 30 - 50 μm, which is used on the surface layer of the thermal protection coating to play the role of resisting water and oxygen corrosion, heat insulation, and temperature reduction;

[0013] The total thickness of the multi-layer structure thermal protection coating is 290 - 380 μm;

[0014] Within the multi-layer structure thermal protection coating, from the silicate top layer to the bond coat, the composition gradually transitions from silicate to YSZ, and the thermal expansion coefficient of the coating shows a gradient change, playing the role of alleviating thermal mismatch;

[0015] Within the multi-layer structure thermal protection coating, the microstructures of the YSZ intermediate layer, the YSZ + silicate functional transition layer, and the silicate top layer material are one or two of micron or nano.

[0016] A preparation method of the above multi-layer structure thermal protection coating applicable to a hydrogen fuel gas turbine includes the following steps:

[0017] Step (1) Superalloy substrate treatment: Clean and process its surface to achieve the required roughness for spraying. The specific steps are as follows: Treat its surface by fine grinding, ultrasonically clean it with alcohol or acetone, then sandblast or laser process its surface to increase its roughness. After reaching the required roughness for spraying, continue ultrasonic cleaning and dry it in an oven at 60 - 90 °C for later use;

[0018] Step (2) Bond coat spraying: Spray the MCrAlY spray feedstock on the substrate surface to obtain a bond coat, where: the MCrAlY spray feedstock is a micron-sized powder with a diameter between 15 and 80 μm, and the spraying method is one or more of atmospheric plasma spraying (APS), high velocity oxy-fuel spraying (HVOF), and high velocity oxy-fuel spraying (HVOF); when using high velocity oxy-fuel spraying (HVOF), the preparation parameters of the bond coat are: the carrier gas is N 2 , the carrier gas flow rate is 15 - 20 NLPM, the shielding gas flow rate is 320 - 380 NLPM, the methane flow rate is 160 - 180 NLPM, the powder feeding rate is 25 - 42 g / min, and the spraying distance is 200 - 300 mm;

[0019] Step (3) YSZ intermediate layer spraying: Spray the YSZ spray feedstock on the bond coat surface to obtain a YSZ intermediate layer, where: the YSZ spray feedstock is a micron-sized powder with a diameter between 15 and 80 μm, and the spraying method is one or more of atmospheric plasma spraying (APS), high velocity oxy-fuel spraying (HVOF), and high velocity oxy-fuel spraying (HVOF); when using atmospheric plasma spraying (APS), the preparation parameters of the YSZ intermediate layer are: the spraying current is 500 - 600 A, the voltage is 65 - 80 V, the spraying power is 32 - 48 KW, the main gas is argon with a flow rate of 38 - 42 SCFH, the auxiliary gas is hydrogen with an auxiliary gas flow rate of 10 - 14 SCFH, the powder feeding mode is a rotary disk type, the rotary disk speed is 35 - 45 r / min, and the carrier gas flow rate is 2 - 3 SCFH;

[0020] Step (4) YSZ + silicate functional transition layer spraying: Premix Yb 2 SiO 5 and the YSZ spray feedstock evenly, where Yb 2 SiO 5 the spray feedstock is a micron-sized powder with a diameter between 15 and 80 μm, Yb 2 SiO 5The proportion can be arbitrarily changed within the given range of 51-99%. The sum of the two materials is 100%. By regulating the structure and composition of the materials, while improving the thermal shock resistance of the coating, it also has the function of resisting water and oxygen corrosion. Spray the sprayable feed mixture on the surface of the YSZ intermediate layer to obtain a silicate + YSZ functional transition layer. The spraying method uses one or several of atmospheric plasma spraying (APS), high-velocity oxy-fuel spraying (HVOF), and high-velocity oxy-fuel spraying (HVOF). When using atmospheric plasma spraying (APS), the preparation parameters of the silicate + YSZ functional transition layer are: spraying current is 400-650A, voltage is 65-100V, spraying power is 32-55KW, the main gas is argon, the flow rate is 38-43SCFH, the auxiliary gas is hydrogen, the auxiliary gas flow rate is 10-15SCFH, the powder feeding mode is rotary, the rotary speed is 20-40r / min, and the carrier gas flow rate is 2-3SCFH;

[0021] Step (5) Spraying of the silicate top layer: Spray Yb 2 SiO 5 The sprayable feed on the surface of the silicate + YSZ functional transition layer to obtain a silicate top layer that resists corrosion in a high-temperature water and oxygen environment, and then obtain a multi-layer structure thermal protection coating suitable for a hydrogen fuel gas turbine. By increasing the silicate + YSZ functional transition layer in this coating; the spraying method uses one or several of atmospheric plasma spraying (APS), high-velocity oxy-fuel spraying (HVOF), and high-velocity oxy-fuel spraying (HVOF). When using atmospheric plasma spraying (APS), the preparation parameters of the silicate top layer are: spraying current is 400-550A, voltage is 80-100V, spraying power is 32-55KW, the main gas is argon, the flow rate is 38-43SCFH, the auxiliary gas is hydrogen, the auxiliary gas flow rate is 10-15SCFH, the powder feeding mode is rotary, the rotary speed is 20-40r / min, and the carrier gas flow rate is 2-3SCFH.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The present invention provides a multi-layer structure thermal protection coating suitable for a hydrogen fuel gas turbine and its preparation method in view of the defects of the existing YSZ coating and the use environment of the hydrogen fuel gas turbine. This new structure coating can be applied in a pure hydrogen fuel gas turbine.

[0024] 2. The top - layer silicate coating of the multi - layer structure thermal protection coating of the present invention is dense, with fewer defects such as pores and micro - cracks. It not only effectively resists water - oxygen corrosion but also plays a partial heat - insulation role. In the remaining unmelted area of the top layer, the existence of micropores significantly increases the surface free energy of this area, promoting the densification process of the unmelted area to accelerate and peeling off from the layered structure formed during the spraying process, ultimately resulting in the formation of larger - sized pores. To a certain extent, these macroscopic pores help to offset the performance degradation caused by the micropore healing phenomenon of the coating in the high - temperature service environment and maintain the overall structural and functional stability of the coating.

[0025] 3. The functional transition layer of the present invention is silicate + YSZ. By controlling the proportion of silicate to be greater than that of YSZ, while alleviating the thermal mismatch in the transition layer, it also has the function of resisting water - oxygen corrosion, reducing the residual stress generated during the shrinkage process of the coating, and reducing the internal thermal stress, thereby improving the thermal cycle life.

[0026] 4. Controlling the proportion of silicate to be greater than that of YSZ in the present invention can effectively ensure the overall water - oxygen corrosion resistance of the coating. According to the actual requirements of the superalloy for hydrogen - fueled gas turbines for the thermal protection coating, adjusting the proportion can more specifically protect the alloy substrate from environmental corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic structural diagram of the multi - layer structure thermal protection coating applicable to hydrogen - fueled gas turbines of the present invention.

[0028] Figure 2 It is an SEM image of the multi - layer structure thermal protection coating prepared in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The technical solutions of the present invention will be further described below in conjunction with the embodiments, but are not limited thereto. Any modification or equivalent replacement of the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention shall be covered by the protection scope of the present invention.

[0030] Example 1:

[0031] This example provides a preparation method for a multi - layer structure thermal protection coating applicable to hydrogen - fueled gas turbines. The method includes the following steps:

[0032] (1) Use 400 - mesh to 800 - mesh SiC sandpaper to finely grind the surface of the GH3230 substrate, ultrasonically clean it with alcohol or acetone for 10 min, and then use SiC sand grains to blast on the smooth and clean surface to increase its roughness, with the roughness value between 2.00 and 4.00 μm. After reaching the required roughness for spraying, ultrasonically clean it with alcohol for 5 min and dry it in an oven at 60 °C for later use.

[0033] (2) The NiCrAlYCe alloy bond coat is prepared on the surface of the substrate treated in step (1) by using the high velocity oxygen fuel (HVOF) spraying technique. The preparation parameters of the bond coat are as follows: the carrier gas is N 2 , the carrier gas flow rate is 15 NLPM, the shielding gas flow rate is 320 NLPM, the methane flow rate is 170 NLPM, the powder feeding rate is 32 g / min, and the spraying distance is 280 mm. The thickness of the obtained NiCrAlYCe alloy bond coat is 105 μm.

[0034] (3) The yttria-stabilized zirconia (YSZ) spray feedstock is sprayed on the surface of the bond coat prepared in step (2) by using the air plasma spraying (APS) to obtain the YSZ intermediate layer in the coating structure. The preparation parameters of the YSZ intermediate layer are as follows: the spraying current is 600 A, the voltage is 75 V, the spraying power is 45 KW, the main gas is argon with a flow rate of 42 SCFH, the auxiliary gas is hydrogen with an auxiliary gas flow rate of 12 SCFH, the powder feeding mode is the rotary disk type, the rotary disk speed is 35 r / min, and the carrier gas flow rate is 2.5 SCFH. The thickness of the obtained YSZ intermediate layer is 130 μm.

[0035] (4) The premixed Yb 2 SiO 5 and the YSZ spray feedstock are sprayed on the surface of the YSZ intermediate layer prepared in step (3) to obtain the silicate + YSZ functional transition layer in the coating structure. Among them, the weight ratio of Yb 2 SiO 5 to YSZ is 70:30. The preparation parameters of the YSZ + silicate + YSZ functional transition layer are as follows: the spraying current is 630 A, the voltage is 70 V, the spraying power is 44.1 KW, the main gas is argon with a flow rate of 38 SCFH, the auxiliary gas is hydrogen with an auxiliary gas flow rate of 11.5 SCFH, the powder feeding mode is the rotary disk type, the rotary disk speed is 32 r / min, and the carrier gas flow rate is 3 SCFH. The thickness of the obtained silicate + YSZ functional transition layer is 35 μm.

[0036] (5) The Yb 2 SiO 5 spray feedstock is sprayed on the surface of the silicate + YSZ functional transition layer prepared in step (4) to obtain the Yb 2 SiO 5 top layer, and then the multi-layered thermal protection coating shown in Figure 1 is obtained. 2 SiO 5The preparation parameters of the top layer are as follows: the current for spraying is 550 A, the voltage is 90 V, the spraying power is 49.5 KW, the main gas is argon with a flow rate of 38 SCFH, the auxiliary gas is hydrogen with an auxiliary gas flow rate of 11.5 SCFH, the powder feeding mode is rotary type, the rotary speed is 32 r / min, and the carrier gas flow rate is 3 SCFH. After spraying, the obtained Yb 2 SiO 5 The thickness of the top layer is 35 μm.

[0037] The SEM image of the multi-layer structure thermal protection coating prepared in this example is as shown in Figure 2 the figure. It can be seen from Figure 2 that in the multi-layer structure thermal protection coating prepared in this example, the thickness and composition of each layer are within the designed range, the combination between layers is good, there is no obvious interface, and the addition of the functional gradient layer can effectively alleviate the drastic changes at the interface while enabling the coating to have the functions of resisting water and oxygen corrosion and extending the service life, effectively protecting the substrate.

[0038] Example 2:

[0039] This example provides a method for preparing a multi-layer structure thermal protection coating suitable for a hydrogen fuel gas turbine, and the method includes the following steps:

[0040] (1) The surface of the GH3230 substrate is finely ground with 400-mesh to 800-mesh SiC sandpaper, ultrasonically cleaned with alcohol or acetone for 10 min, and then the surface roughness is increased by sandblasting with SiC sand grains on the smooth and clean surface, and the roughness value is between 2.00 and 4.00 μm. After reaching the required roughness for spraying, it is ultrasonically cleaned with alcohol for 5 min and dried in an oven at 60 °C for standby.

[0041] (2) The NiCrAlYSi alloy bonding bottom layer is prepared on the surface of the substrate treated in step (1) by using the high-velocity oxy-fuel (HVOF) spraying technology. The preparation parameters of the bonding bottom layer are as follows: the carrier gas is N 2 , the carrier gas flow rate is 20 NLPM, the shielding gas flow rate is 380 NLPM, the methane flow rate is 180 NLPM, the powder feeding rate is 40 g / min, and the spraying distance is 250 mm. The thickness of the obtained NiCrAlYSi alloy bonding bottom layer after spraying is 105 μm.

[0042] (3) The YSZ sprayable feedstock is sprayed onto the surface of the bond coat prepared in step (2) by atmospheric plasma spraying (APS) to obtain the YSZ intermediate layer in the coating structure. The preparation parameters of the YSZ intermediate layer are as follows: the spraying current is 585 A, the voltage is 70 V, the spraying power is 41 KW, the main gas is argon with a flow rate of 40 SCFH, the auxiliary gas is hydrogen with an auxiliary gas flow rate of 11 SCFH, the powder feeding mode is rotary disk type, the rotary disk speed is 38 r / min, and the carrier gas flow rate is 2.5 SCFH. The thickness of the YSZ intermediate layer obtained after spraying is 130 μm.

[0043] (4) The premixed Yb 2 SiO 5 and the YSZ sprayable feedstock are sprayed onto the surface of the YSZ intermediate layer prepared in step (3) to obtain the silicate + YSZ functional transition layer in the coating structure. Among them, the weight ratio of Yb 2 SiO 5 to YSZ is 90:10. The preparation parameters of the YSZ + silicate + YSZ functional transition layer are as follows: the spraying current is 620 A, the voltage is 70 V, the spraying power is 43.4 KW, the main gas is argon with a flow rate of 38 SCFH, the auxiliary gas is hydrogen with an auxiliary gas flow rate of 11.5 SCFH, the powder feeding mode is rotary disk type, the rotary disk speed is 32 r / min, and the carrier gas flow rate is 3 SCFH. The thickness of the silicate + YSZ functional transition layer obtained after spraying is 35 μm.

[0044] (5) The Yb 2 SiO 5 sprayable feedstock is sprayed onto the surface of the silicate + YSZ functional transition layer prepared in step (4) to obtain the Yb 2 SiO 5 top layer, and then the Figure 1 multi-layer thermal protection coating shown is obtained. The preparation parameters of the Yb 2 SiO 5 top layer are as follows: the spraying current is 400 A, the voltage is 90 V, the spraying power is 36 KW, the main gas is argon with a flow rate of 38 SCFH, the auxiliary gas is hydrogen with an auxiliary gas flow rate of 11.5 SCFH, the powder feeding mode is rotary disk type, the rotary disk speed is 32 r / min, and the carrier gas flow rate is 3 SCFH. The thickness of the Yb 2 SiO 5 top layer obtained after spraying is 35 μm.

[0045] Example 3:

[0046] The difference between this example and Examples 1 and 2 is that Yb 2 SiO 5The weight ratio to YSZ is 55:45, the material of the bonding bottom layer is CoCrAlYCe, the thickness of the bonding bottom layer is 120 μm, the thickness of the YSZ intermediate layer is 115 μm, the thickness of the silicate + YSZ functional transition layer is 40 μm, and the thickness of the silicate top layer is 45 μm.

Claims

1. A multi-layer thermal protection coating suitable for hydrogen fuel gas turbines, characterized in that The multi-layer thermal protective coating takes a high-temperature alloy as a substrate, and a bonding bottom layer, a YSZ middle layer, a silicate + YSZ functional transition layer and a silicate top layer are sprayed on the surface of the substrate in sequence. The material of the silicate + YSZ functional transition layer is a premix of YSZ and silicate, wherein the mass proportion of silicate is 51-99%, the structure and composition of YSZ are the same as those of the material used in the YSZ middle layer, and the structure and composition of silicate are the same as those of the material used in the silicate top layer.

2. The multi-layer thermal protection coating suitable for hydrogen fuel gas turbine according to claim 1, characterized in that The high-temperature alloy substrate has a diameter of 25.4 mm and a thickness of 3 to 20 mm, and is one or more of a nickel-based high-temperature alloy and a cobalt-based high-temperature alloy.

3. The multi-layer thermal protection coating suitable for hydrogen fuel gas turbine according to claim 1, characterized in that The total thickness of the multi-layer thermal protection coating is 290-380 μm, the thickness of the bonding bottom layer is 100-130 μm, the thickness of the YSZ middle layer is 100-150 μm, the thickness of the silicate+YSZ functional transition layer is 30-50 μm, and the thickness of the silicate top layer is 30-50 μm.

4. The multi-layer thermal protection coating suitable for hydrogen fuel gas turbine according to claim 1 or 3, characterized in that The material of the bonding bottom layer is MCrAlY.

5. The multi-layer thermal protection coating suitable for hydrogen fuel gas turbine according to claim 4, characterized in that The MCrAlY is one or more of NiCrAlYCe, NiCrAlYSi, and CoCrAlYCe.

6. The multi-layer thermal protection coating suitable for hydrogen fuel gas turbine according to claim 1 or 3, characterized in that The material of the YSZ intermediate layer is YSZ.

7. The multi-layer thermal protection coating suitable for hydrogen fuel gas turbine according to claim 1 or 3, characterized in that The material of the silicate top layer is Yb2SiO5.

8. A method for preparing a multilayer thermal protective coating suitable for a hydrogen fuel gas turbine according to any one of claims 1 to 7, characterized in that The method comprises the following steps: Step (1) high temperature alloy substrate treatment: cleaning and processing the surface of the substrate to achieve the required roughness for spraying; Step (2) spraying the bonding bottom layer: spraying the MCrAlY sprayable feed material on the surface of the substrate to obtain the bonding bottom layer; Step (3) spraying a YSZ intermediate layer: spraying a YSZ sprayable feed material on the surface of the bonding bottom layer to obtain a YSZ intermediate layer; Step (4) Spraying of silicate + YSZ functional transition layer: premixing a YSZ sprayable feed with a Yb2SiO5 sprayable feed, and spraying the sprayable feed mixture on the surface of the YSZ intermediate layer to obtain a silicate + YSZ functional transition layer; Step (5) Spraying of silicate top layer: spraying Yb2SiO5 sprayable feed material on the surface of YSZ+silicate functional transition layer to obtain silicate top layer, and then obtaining a multi-layer structure thermal protection coating.

9. The method for preparing a multi-layer thermal protective coating according to claim 8, characterized in that The MCrAlY sprayable feed material is a micron-sized powder; the YSZ sprayable feed material is a micron-sized powder; the Yb2SiO5 sprayable feed material is a micron-sized powder; the spraying methods all adopt one or more of atmospheric plasma spraying, supersonic flame spraying, and supersonic flame spraying.

10. Use of the multi-layer thermal protection coating according to any one of claims 1 to 7 in a hydrogen fuel gas turbine.

Images