Thermal barrier coating and high-temperature-resistant component

Abstract

In order to solve the problem that an existing thermal barrier coating is insufficient in thermal shock resistance and sintering resistance, the thermal barrier coating comprises a heat insulation bottom layer and a high strain tolerance layer, the heat insulation bottom layer is located on the lower layer of the high strain tolerance layer, the heat insulation bottom layer comprises lamellar yttrium-stabilized zirconium oxide with lamellar units stacked, and the lamellar yttrium-stabilized zirconium oxide is located on the lower layer of the high strain tolerance layer. The high strain tolerance layer comprises high strain tolerance yttrium-stabilized zirconium oxide, and the high strain tolerance yttrium-stabilized zirconium oxide has one or more of a vertical crack structure, a columnar structure and a porous structure. Meanwhile, the utility model further discloses a high-temperature-resistant component comprising the thermal barrier coating. According to the thermal barrier coating provided by the utility model, the thermal shock resistance and the sintering resistance of the coating can be remarkably improved while better thermal insulation performance is maintained.

Description

Technical Field

[0001] The utility model belongs to the technical field of high-temperature protective coatings, and in particular relates to a thermal barrier coating and a high-temperature resistant component. Background Art

[0002] Small and medium-sized gas turbines, due to their rapid start-up and shutdown capabilities and easy maintenance, offer significant advantages and broad application prospects compared to other large-scale power generation equipment in the field of power peak regulation. Due to the fluctuating and random nature of grid loads, the grid is often overloaded during peak demand periods. During these periods, generator sets outside of normal operation are required to meet demand. These generator sets are called peak-shaving units. The fundamental requirements for peak-shaving units are fast start-up and shutdown speeds and high frequency to meet the synchronization requirements of grid connection. This means that peak-shaving gas turbines require frequent start-up and shutdown, posing a significant challenge to the thermal shock resistance of the gas turbine's thermal barrier coating.

[0003] Among the hot-end components of a gas turbine, turbine blades are considered the most critical due to their high operating temperatures, complex stresses, and harsh environments. The first-stage guide vanes, located at the combustion chamber exit, play a crucial role in guiding the high-temperature gases generated within the combustion chamber and optimizing the flow direction and velocity. Therefore, they present the most pressing need for thermal barrier coatings.

[0004] Thermal barrier coating (TBC) is a surface protection technology for high-temperature structural materials that utilizes the excellent high-temperature resistance, heat insulation, and corrosion resistance of ceramic materials by combining ceramics with a metal substrate in the form of a coating. It typically consists of a low-thermal-conductivity ceramic surface layer and a metal bonding layer. Research has shown that applying a 150μm-thick thermal barrier coating on the surface of a first-stage turbine blade can reduce the operating temperature of the blade's high-temperature alloy surface by over 50°C, increasing the blade's service life by more than three times, while also improving efficiency and reducing emissions.

[0005] YSZ (yttrium-stabilized zirconia) is often used as the primary material for thermal barrier coatings due to its high thermal stability and low thermal conductivity. There are various methods for preparing YSZ layers, the most common of which is the APS process (atmospheric plasma spraying), which can form a lamellar structure with good thermal insulation properties. However, this type of APS YSZ has insufficient thermal shock resistance, which can easily cause the coating to fall off under long-term thermal shock. In addition, APS YSZ has insufficient anti-sintering performance and is prone to adhesion under high temperature conditions, affecting the thermal insulation performance of the thermal barrier coating and ultimately the protection of the turbine blades. Utility Model Content

[0006] Aiming at the problem that existing thermal barrier coatings have insufficient thermal shock resistance and sintering resistance, the utility model provides a thermal barrier coating and a high-temperature resistant component.

[0007] The technical solutions adopted by the present invention to solve the above technical problems are as follows:

[0008] On the one hand, the utility model provides a thermal barrier coating, comprising a thermal insulation base layer and a high strain tolerance layer, wherein the thermal insulation base layer is located below the high strain tolerance layer, the thermal insulation base layer comprises a lamellar yttrium-stabilized zirconia having stacked lamellar units, and the high strain tolerance layer comprises a high strain tolerance yttrium-stabilized zirconia, wherein the high strain tolerance yttrium-stabilized zirconia has one or more of a vertical crack structure, a columnar structure, and a porous structure.

[0009] Optionally, the thickness of the thermal insulation bottom layer is 50-500 μm.

[0010] In the thermal insulation bottom layer, the transverse major diameter of the sheet unit is 5-30 μm, and the longitudinal thickness is 2-10 μm.

[0011] Optionally, the porosity of the thermal insulation bottom layer is 5% to 25%.

[0012] Optionally, the high strain tolerance layer has a thickness of 60-300 μm.

[0013] Optionally, the vertical crack structure includes a plurality of cracks extending along the thickness direction of the high strain tolerance layer, the cracks have a depth of 60 to 300 μm, a width of 0.3 to 3 μm, and a density of 2 to 10 mm -1 ;

[0014] The columnar structure includes a plurality of columnar microstructures extending along the thickness direction of the high strain tolerance layer, the height of the columnar microstructure is 60-300 μm, and the density is 5-30 mm -1 ;

[0015] The porous structure includes a plurality of micropores formed inside the high strain tolerance layer, the pore diameter of the micropores is 0.5-5 μm, and the porosity of the porous structure is 25%-45%.

[0016] Optionally, a bonding layer is further included, the bonding layer being located on a side of the thermal insulation bottom layer away from the high strain tolerance layer, the bonding layer comprising MCrAlY or MCrAlTaY, wherein M is Ni and / or Co,

[0017] The thickness of the adhesive layer is 50-200 μm.

[0018] On the other hand, the present invention provides a high-temperature resistant component, including a hot end component and the thermal barrier coating as described above, wherein the thermal barrier coating is arranged on the surface of the hot end component, and the hot end component includes a turbine blade, a combustion chamber, a heat shield, a nozzle, a flame tube or a tail nozzle.

[0019] According to the thermal barrier coating provided by the present invention, a lamellar yttrium-stabilized zirconia is used as a thermal insulation bottom layer, wherein the lamellar yttrium-stabilized zirconia has a lamellar unit stacking structure, and the interlayer gap formed therein can effectively reduce the longitudinal thermal conductivity, thereby effectively blocking the heat conduction of the high temperature environment to the hot end components; in view of the problem that the lamellar yttrium-stabilized zirconia has insufficient thermal shock resistance and sintering resistance, a high strain tolerance yttrium-stabilized zirconia is applied on the surface of the lamellar yttrium-stabilized zirconia as a high strain tolerance layer, and the high strain tolerance yttrium-stabilized zirconia has one or more of a vertical crack structure, a columnar structure and a porous structure. The high Strain-tolerant yttrium-stabilized zirconia has good sintering resistance and can reduce the thermal mismatch stress of the surface layer under the action of thermal shock, thereby avoiding premature peeling and failure of the surface layer. Correspondingly, the presence of the lamellar yttrium-stabilized zirconia is also conducive to further improving the thermal shock resistance of the high-strain-tolerance yttrium-stabilized zirconia. Therefore, compared with a single lamellar yttrium-stabilized zirconia or a single high-strain-tolerance yttrium-stabilized zirconia, the composite structure formed by the lamellar yttrium-stabilized zirconia and the high-strain-tolerance yttrium-stabilized zirconia exhibits better synergistic effect, while maintaining good thermal insulation performance, it can significantly improve the thermal shock resistance and sintering resistance of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of the thermal barrier coating provided by the utility model;

[0021] Figure 2 This is the SEM cross-sectional morphology of the thermal barrier coating system obtained in Example 1;

[0022] Figure 3 This is the high-magnification SEM cross-sectional morphology of the thermal barrier coating system obtained in Example 1;

[0023] Figure 4 This is the SEM cross-sectional morphology of the thermal barrier coating system obtained in Example 2;

[0024] Figure 5 This is the metallographic cross-sectional morphology of the thermal barrier coating at the air inlet edge of the blade obtained in Example 3;

[0025] Figure 6 This is the SEM cross-sectional morphology of the thermal barrier coating system obtained in Comparative Example 1;

[0026] Figure 7 This is the SEM cross-sectional morphology of the thermal barrier coating system obtained in Comparative Example 2;

[0027] Figure 8 This is the SEM cross-sectional morphology of the thermal barrier coating system obtained in Comparative Example 3;

[0028] Figure 9 Schematic diagram of the radial atomization suspension plasma spraying process parameter space.

[0029] The reference numerals in the drawings of the specification are as follows:

[0030] 1. High strain tolerance layer; 2. Thermal insulation base layer; 3. Adhesive layer; 4. Hot end component. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] In the description of the present invention, when a layer is described as being "on" or "over" another layer or substrate, it should be understood that, unless explicitly stated otherwise, these layers may be in direct contact with each other or have another layer or feature between them. Therefore, these terms simply describe the relative position of the layers to each other and do not necessarily mean "above", as the relative position of above or below depends on the orientation of the device relative to the viewer.

[0033] See also Figure 1 As shown, an embodiment of the present invention provides a thermal barrier coating, comprising a thermal insulation base layer 2 and a high strain tolerance layer 1, wherein the thermal insulation base layer 2 is located below the high strain tolerance layer 1, and the thermal insulation base layer 2 comprises a lamellar yttrium-stabilized zirconia having stacked lamellar units, and the high strain tolerance layer 1 comprises a high strain tolerance yttrium-stabilized zirconia, and the high strain tolerance yttrium-stabilized zirconia has one or more of a vertical crack structure, a columnar structure, and a porous structure.

[0034] Among them, the lamellar yttrium-stabilized zirconia has a lamellar unit stacking structure, and the interlayer gap formed therein can effectively reduce the longitudinal thermal conductivity, thereby effectively blocking the heat conduction of the hot end component 4 by the high temperature of the environment; in view of the problem that the lamellar yttrium-stabilized zirconia has insufficient thermal shock resistance and sintering resistance, a high strain tolerance yttrium-stabilized zirconia is applied on the surface of the lamellar yttrium-stabilized zirconia as a high strain tolerance layer 1, and the high strain tolerance yttrium-stabilized zirconia has one or more of a vertical crack structure, a columnar structure and a porous structure. The high strain tolerance yttrium-stabilized zirconia of this structure has good The invention has anti-sintering performance, and can reduce the thermal mismatch stress of the surface layer under the action of thermal shock, thereby avoiding premature peeling and failure of the surface layer. Correspondingly, the presence of the lamellar yttrium-stabilized zirconia is also conducive to further improving the thermal shock resistance of the high strain tolerance yttrium-stabilized zirconia. Therefore, compared with a single lamellar yttrium-stabilized zirconia or a single high strain tolerance yttrium-stabilized zirconia, the composite structure formed by the lamellar yttrium-stabilized zirconia and the high strain tolerance yttrium-stabilized zirconia exhibits better synergistic effect, while maintaining good thermal insulation performance, it can significantly improve the thermal shock resistance and sintering resistance of the coating.

[0035] In some embodiments, the thickness of the thermal insulation bottom layer 2 is 50-500 μm.

[0036] In a preferred embodiment, the thickness of the thermal insulation bottom layer 2 is 150-200 μm. Specifically, the thickness of the thermal insulation bottom layer 2 can be 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, or any range therebetween.

[0037] The lamellar yttrium-stabilized zirconia in the thermal insulation bottom layer 2 can be prepared by atmospheric plasma spraying, has a lamellar structure, and has low thermal conductivity. When the thickness of the thermal insulation bottom layer 2 is too low, it is not conducive to the high-temperature protection of the hot end component 4; when the thickness of the thermal insulation bottom layer 2 is too high, it increases the risk of it falling off under thermal shock conditions.

[0038] In some embodiments, in the thermal insulation bottom layer 2, the transverse major axis of the sheet unit is 5-30 μm, and the longitudinal thickness is 2-10 μm.

[0039] In some embodiments, the porosity of the thermal insulation bottom layer 2 is 5% to 25%.

[0040] Porosity is an important feature of lamellar yttrium-stabilized zirconia. When the porosity of the thermal insulation bottom layer 2 is within the above range, it is beneficial to reduce thermal conductivity and improve thermal insulation performance.

[0041] In some embodiments, the high strain tolerance layer 1 has a thickness of 60-300 μm.

[0042] In a preferred embodiment, the thickness of the high strain tolerance layer 1 is 100-150 μm. Specifically, the thickness of the high strain tolerance layer 1 can be 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, or any range therebetween.

[0043] The high strain tolerance provided by the high-strain-tolerance yttrium-stabilized zirconia allows the thermal barrier coating to better withstand the effects of thermal stress during thermal shock, making it less susceptible to vertical cracking and other structural issues. This reduces the risk of premature spalling and improves the thermal shock lifespan. However, if the high-strain-tolerance layer 1 is too thin, it will be difficult to effectively withstand the stress caused by thermal shock. Long-term thermal shock can easily expose the thermal insulation base layer 2, leading to the shedding of the thermal barrier coating.

[0044] The high strain tolerance layer 1 is prepared by atomized suspension plasma spraying. By adjusting the spraying process parameters, a high strain tolerance yttrium-stabilized zirconia having a vertical crack structure, a columnar structure, a porous structure or a combination of these structures can be formed.

[0045] In some embodiments, the vertical crack structure includes a plurality of cracks extending along the thickness direction of the high strain tolerance layer 1, wherein the cracks have a depth of 60 to 300 μm, a width of 0.3 to 3 μm, and a density of 2 to 10 mm. -1 .

[0046] When the high strain-tolerant layer 1 includes the vertical crack structure, it typically has a relatively dense structure. In some cases, the vertical crack structure includes micropores at non-crack locations. The presence of cracks in the vertical crack structure provides the high strain-tolerant layer 1 with high strain tolerance. It is believed that during a thermal shock process, the cracks can accommodate the thermal expansion strain generated by the high strain-tolerant layer 1, thereby preventing the formation of internal stress during the thermal shock process that could cause the high strain-tolerant layer 1 to fall off. Adjacent cracks in the high strain-tolerant layer 1 may be interconnected or independent.

[0047] In some embodiments, the columnar structure includes a plurality of columnar microstructures extending along the thickness direction of the high strain tolerance layer 1, wherein the height of the columnar microstructure is 60-300 μm and the density is 5-30 mm -1 .

[0048] The columnar structure is another high strain tolerance structure, different from the vertical crack structure. It is characterized by having multiple columnar microstructures extending along the thickness of the high strain tolerance layer 1. These columnar microstructures can be feather-shaped or other columnar structures. Adjacent columnar microstructures exhibit distinct directional alignment characteristics, with crystals not fully aligned, leaving gaps to achieve high strain tolerance. When the high strain tolerance layer 1 includes the columnar structure, it can also include a porous structure as described below.

[0049] In some embodiments, the porous structure includes a plurality of micropores formed inside the high strain tolerance layer 1 , the pore diameter of the micropores is 0.5-5 μm, and the porosity of the porous structure is 25%-45%.

[0050] The porous structure is usually accompanied by a vertical crack structure and a columnar structure. However, under certain conditions (by adjusting the atomized suspension plasma spraying parameters), a high strain tolerance layer 1 having a porous structure alone can also be achieved. The micropores within the porous structure have the effect of improving the overall thermal insulation performance of the high strain tolerance layer 1.

[0051] In some embodiments, the thermal barrier coating further includes a bonding layer 3, which is located on a side of the thermal insulation base layer 2 away from the high strain tolerance layer 1, and the bonding layer 3 includes at least one of MCrAlY and MCrAlTaY, wherein M is Ni and / or Co.

[0052] The bonding layer 3 is used to improve the bonding strength between the thermal insulation base layer 2 and the surface of the hot end component 4. When the bonding layer 3 is selected from MCrAlY and / or MCrAlTaY, it has good compatibility with both the hot end component 4 and the thermal insulation base layer 2, thereby improving the bonding performance of the thermal barrier coating.

[0053] In some embodiments, the thickness of the adhesive layer 3 is 50-200 μm.

[0054] Another embodiment of the present invention provides a high-temperature resistant component, comprising a hot end component 4 and the thermal barrier coating as described above, wherein the thermal barrier coating is disposed on the surface of the hot end component 4 .

[0055] The thermal barrier coating can significantly improve the thermal shock resistance and sintering resistance of the coating while maintaining good thermal insulation performance; by applying the thermal barrier coating to the surface of the hot end component 4, it is beneficial to improve the thermal shock resistance and high-temperature service life of the hot end component 4.

[0056] In some embodiments, the hot end component 4 includes a turbine blade, a combustion chamber, a heat shield, a nozzle, a flame tube or a tail nozzle.

[0057] Exemplary applications of the hot end components 4 include turbine components, specifically, those located within the combustion section (e.g., combustor, liner, and / or heat shield), or turbine sections (e.g., turbine blades, blades, and / or shrouds). Applications of the turbine components include high-bypass turbofan jet engines, turbojet engines, turboprop engines, or turboshaft gas turbine engines, as well as industrial and marine gas turbine engines and auxiliary power units.

[0058] In one embodiment, the hot end component 4 is selected from a turbine guide blade, and the turbine guide blade includes a blade body, an upper rafter plate and a lower rafter plate, and the blade body is divided into four parts: a blade back, a blade basin, an air inlet edge and an exhaust edge.

[0059] Another embodiment of the present invention provides a method for preparing the thermal barrier coating as described above, comprising the following steps:

[0060] Yttrium-stabilized zirconia powder is used as a raw material for atmospheric plasma spraying to form a layer of yttrium-stabilized zirconia with stacked layer units to obtain a thermal insulation bottom layer;

[0061] Yttrium-stabilized zirconia suspension is used for atomized suspension plasma spraying to form a high strain tolerance layer on the surface of the thermal insulation base layer.

[0062] This application proposes a composite thermal barrier coating system comprising a thermally insulating base layer of yttria-stabilized zirconia and a high-strain-tolerance layer with various structures, as well as a coating preparation and control method based on plasma spray equipment. Compared to the APS coating technology currently widely used in the preparation of thermal barrier coatings for gas turbine blades, this system is essentially comparable in cost to the APS coating technology currently used. This system can be used to obtain the required high-strain-tolerance thermal barrier coating structure at a low cost, tailored to the actual needs of gas turbine hot-end components. This thermal barrier coating exhibits a variety of excellent properties, including excellent thermal insulation, high thermal shock life, and high sintering resistance. Furthermore, the preparation method provided in this application is particularly suitable for surface thermal barrier coatings on hot-end components with three-dimensional surfaces, such as turbine guide vanes, and can form a high-strain-tolerance layer and thermally insulating base layer with relatively uniform thickness.

[0063] In some embodiments, the preparation method further comprises:

[0064] MCrAlY and / or MCrAlTaY are used as raw materials for hypersonic flame spraying, where M is Ni and / or Co, to prepare a bonding layer on the hot end component. The spraying parameters are: kerosene 25-30 L / h, oxygen 800-900 L / h, and spray distance 300-350 mm.

[0065] In some embodiments, the parameters of the atmospheric plasma spraying are: ion spraying current is 450-500A, spraying distance is 110-120mm; spray gun swing rate is 500-600mm / s; Ar gas flow rate is 30-35slpm; H2 flow rate is 6-8slpm.

[0066] Suspension plasma spraying is a novel thermal spraying technology for producing thermal barrier coatings with advanced structures. By introducing the thermal barrier coating powder material into the plasma plume in the form of a suspension, this technology fundamentally addresses the problems of easy agglomeration and insufficient fluidity of nano- and submicron-sized powders. This technology leverages the unique flight characteristics of nano- and submicron-sized powders in the plasma plume to produce thermal barrier coatings with high strain tolerance structures, such as vertical cracks and columnar structures. This technology also maintains a high porosity, thereby reducing the coating's thermal conductivity. This overcomes the insufficient thermal insulation performance of thermal barrier coatings with dense vertical crack structures produced by APS and columnar structures produced by EB-PVD.

[0067] Suspension plasma spraying employs two feeding methods: axial and radial. Due to limitations in feed type and power, radial feeding typically requires a shorter spray distance, typically within the 40-60mm range. However, radial feeding offers a wider range of equipment applicability and lower production costs, making it more suitable for thermal barrier coating applications on small and medium-sized gas turbines. While axial feeding, based on multi-electrode plasma spray equipment, offers a longer spray distance (>60mm) and a wider process window, its higher cost makes it unsuitable for thermal barrier coating applications on small and medium-sized gas turbine blades.

[0068] In some embodiments, the atomized suspension plasma spraying adopts radial atomized suspension plasma spraying, and the parameters are: plasma spraying current is 600-650A; spraying distance is 60-95mm; Ar gas flow rate is 30-70slpm; H2 flow rate is 10-12slpm; suspension solid content is 18-30%; suspension feeding rate is 20-35ml / min; atomization pressure is 0.04-0.05MPa.

[0069] The method for controlling the morphology of the high strain tolerance layer is based on the control of radial atomization suspension plasma spraying process parameters, wherein the spraying distance and Ar gas flow rate are important factors affecting the morphology of the high strain tolerance layer, such as Figure 9 As shown in the figure, the X-axis is the inverse of the spraying distance, and the Y-axis is the Ar gas flow rate. The momentum and melting degree of the particles are controlled by adjusting key process parameters such as the Ar gas flow rate and the spraying distance. The higher the momentum and melting degree of the particles, the more the coating tends to be dense and with vertical crack structures. Conversely, the coating tends to have high porosity, columnar structure or porous structure.

[0070] The present invention is further described below through examples.

[0071] Example 1

[0072] This embodiment is used to illustrate the thermal barrier coating and preparation method disclosed in the present invention, including the following steps:

[0073] Ni-based high-temperature alloy is used as the substrate;

[0074] The thermal insulation base layer is prepared by atmospheric plasma spraying of yttrium-stabilized zirconia powder. The spraying parameters are: ion spraying current is 450-500A, spraying distance is 110-120mm; spray gun swing rate is 500-600mm / s; Ar gas flow rate is 30-35slpm; H2 flow rate is 6-8slpm; powder feeding amount is 1.9-2.2; thermal insulation base layer thickness is 150-160um.

[0075] A high strain tolerance layer was prepared by radial atomization suspension plasma spraying of yttrium-stabilized zirconia suspension. The spraying parameters were: plasma spraying current of 600-650A; spraying distance of 90-95mm; Ar gas flow rate of 50-55slpm; H2 flow rate of 10-12slpm; suspension solid content of 18-20%; suspension feed rate of 20-25ml / min; atomization pressure of 0.04-0.05MPa; and high strain tolerance layer thickness of 150-160um.

[0076] The composite thermal barrier coating prepared in this embodiment has a structure such as Figure 2 As shown in FIG, during the preparation of the high strain tolerance layer, when the particles approach the thermal insulation bottom layer, the plasma drag force changes the particle trajectory from perpendicular to the surface of the thermal insulation bottom layer to along the surface of the thermal insulation bottom layer. These particles collide with the microscopic peaks on the surface, generating a shadow effect. The columns grow at the protrusions to form a columnar structure. Due to the high spray distance, the momentum of the particles becomes lower when they reach the thermal insulation bottom layer. The degree of bonding between the plates after the particles are melted is reduced, resulting in a high porosity of 27.73%. Figure 3 All shown are submicron and nanometer-scale micropores, which reduce thermal conductivity while also reducing the stress expansion factor, allowing the high strain tolerance layer to have high thermal insulation and high thermal shock resistance. The composite structure thermal barrier coating combines the excellent thermal shock resistance and sintering resistance of the high strain tolerance layer with the low thermal conductivity of the lamellar yttrium-stabilized zirconia structure. Compared with the single-layer lamellar yttrium-stabilized zirconia structure, it has better performance. After 270 water quenchings, only the high strain tolerance layer peeled off.

[0077] The water quenching thermal shock test conditions are: heating at 1100°C for 5 minutes, then immediately water quenching at room temperature for 10 seconds, and repeating the cycle until the coating peeling area exceeds 5%.

[0078] Example 2

[0079] This embodiment is used to illustrate the thermal barrier coating and preparation method disclosed in the present invention, including the following steps:

[0080] Ni-based high-temperature alloy is used as the substrate;

[0081] The thermal insulation base layer is prepared by atmospheric plasma spraying of yttrium-stabilized zirconia powder. The spraying parameters are: ion spraying current is 450-500A, spraying distance is 110-120mm; spray gun swing rate is 500-600mm / s; Ar gas flow rate is 30-35slpm; H2 flow rate is 6-8slpm; powder feeding amount is 1.9-2.2; thermal insulation base layer thickness is 150-160um.

[0082] The high strain tolerance layer was prepared by radial atomization suspension plasma spraying of yttrium-stabilized zirconia suspension, with the spraying distance reduced to 70-75 mm and the Ar gas flow rate increased to 55-60 slpm. Other spraying parameters were the same as those in Example 1.

[0083] The composite thermal barrier coating prepared in this embodiment has a structure such as Figure 4 As shown, during the preparation of the high strain-tolerance layer, the higher deposition temperature improves the bonding between the layers, resulting in good contact between them. This allows the entire high strain-tolerance layer to be treated as a single entity, leading to high thermal conductivity and heat flux. When the molten particles impact the relatively cool insulating base layer, the resulting sheet cools very rapidly. However, cooling contraction is limited by the bulk of the insulating base layer, introducing tensile stresses into the high strain-tolerance layer. When these stresses exceed the strength of the high strain-tolerance layer, vertical cracks form. Due to the reduced spraying distance and increased Ar flow rate, the particles gain higher momentum, reaching the insulating base layer with a higher momentum, forming a high strain-tolerance layer with a dense vertical crack structure. After 260 water quenching cycles, only spalling of the thermal barrier coating occurred.

[0084] The water quenching thermal shock test conditions are: heating at 1100°C for 5 minutes, then immediately water quenching at room temperature for 10 seconds, and repeating the cycle until the coating peeling area exceeds 5%.

[0085] Example 3

[0086] This embodiment is used to illustrate the thermal barrier coating and preparation method disclosed in the present invention, including the following steps:

[0087] The turbine guide blades are clamped on a rotating table, and NiCrAlY is used as the raw material. The bonding layer is prepared by hypersonic flame spraying. The spraying angle is 30-33 degrees relative to the rafters. The spraying parameters are kerosene 25-30L / h, oxygen 800-900L / h, and spray distance 300-350mm.

[0088] The turbine guide blades with a bonding layer are fixed on a workbench, and yttrium-stabilized zirconia powder is used for atmospheric plasma spraying to prepare a thermal insulation base layer. The spraying parameters are: ion spraying current is 450-500A, spraying distance is 110-120mm; spray gun swing rate is 500-600mm / s; Ar gas flow rate is 30-35slpm; H2 flow rate is 6-8slpm; powder feeding amount is 1.9-2.2.

[0089] The turbine guide blade formed with the thermal insulation bottom layer was fixed on a workbench, and a high strain tolerance layer was prepared by radial atomization suspension plasma spraying using a yttrium-stabilized zirconia suspension. The spraying parameters were the same as those in Example 1.

[0090] After testing, the thickness of the thermal insulation bottom layer of the turbine guide blade at the air inlet side is 150-160um, and the thickness of the high strain tolerance layer is 100-110um. Figure 5 The columnar structure shown in the figure has a base insulation thickness of 190-200 μm on the blade back and a high strain tolerance layer of 140-150 μm. The base insulation thickness at the blade basin is 160-170 μm and a high strain tolerance layer of 90-100 μm. The base insulation thickness at the rafters is 150-160 μm and a high strain tolerance layer of 130-140 μm. This embodiment achieves a substantially uniform coating structure and thickness across all blade components.

[0091] Comparative Example 1

[0092] This comparative example is used to illustrate the thermal barrier coating and preparation method disclosed in the present invention, and includes the following steps:

[0093] Ni-based high-temperature alloy is used as the substrate;

[0094] A high strain tolerance layer was prepared by radial atomization suspension plasma spraying of yttrium-stabilized zirconia suspension. The spraying parameters were mostly the same as those in Example 1, except that the spray distance was reduced to 65-70 mm, the Ar gas flow rate was increased to 60-65 slpm, and the thickness of the high strain tolerance layer was 300-400 μm.

[0095] The dense vertical crack single-layer thermal barrier coating prepared in this comparative example has a structure such as Figure 6As shown, during the preparation of the high strain-tolerance layer, the higher deposition temperature improves the bonding between the layers, resulting in good contact between the layers. This allows the entire high strain-tolerance layer to be treated as a single entity, resulting in high thermal conductivity and high heat flux. When the molten particles impact the relatively cold substrate, the resulting sheet cools very quickly. However, cooling contraction is limited by the bulk substrate, introducing tensile stresses into the high strain-tolerance layer. When these stresses exceed the strength of the high strain-tolerance layer, vertical cracks form. Due to the low spray distance and high Ar gas flow rate, the particles melt to a high degree and reach the substrate with high momentum, forming a dense vertical crack thermal barrier coating with a porosity of 11.7%. The increased coating density enhances the coating's bonding strength, reaching 55.61 MPa. The introduction of vertical cracks improves the thermal shock resistance and sintering resistance of the high strain-tolerance layer. However, compared to the composite thermal barrier coating of Example 1, the coating failed after only 210 water quenches, shortening the thermal shock life by approximately 20%.

[0096] Comparative Example 2

[0097] This comparative example is used to illustrate the thermal barrier coating and preparation method disclosed in the present invention, and includes the following steps:

[0098] Ni-based high-temperature alloy is used as the substrate;

[0099] A high strain tolerance layer was prepared by radial atomization suspension plasma spraying of a yttrium-stabilized zirconia suspension. The spraying parameters were largely the same as those in Example 2, except that the Ar gas flow was reduced to 50-55 slpm and the ceramic layer thickness was 300 μm.

[0100] The columnar structure single-layer thermal barrier coating prepared in this comparative example has a structure such as Figure 7 As shown in the figure, when the particles approach the substrate, the plasma drag force changes the trajectory of the particles from perpendicular to the substrate surface to along the substrate surface. These particles collide with the microscopic peaks on the surface, generating a shadow effect. The columns grow on the asperities to form a columnar structure. Due to the reduction in the Ar gas flow rate, the particles gain lower momentum, and the particles are more affected by the plasma drag force, thereby forming a columnar structure and improving the strain tolerance of the coating. However, compared with the composite structure thermal barrier coating of Example 2, the coating failed to peel off after only 200 water quenchings, and the thermal shock life was shortened by about 25%.

[0101] Comparative Example 3

[0102] This comparative example is used to illustrate the thermal barrier coating and preparation method disclosed in the present invention, and includes the following steps:

[0103] Ni-based high-temperature alloy is used as the substrate;

[0104] A high strain tolerance layer was prepared by radial atomization suspension plasma spraying of a yttrium-stabilized zirconia suspension. The spraying parameters were largely the same as those in Example 2, except that the Ar gas flow rate was reduced to 40 slpm; the solid content of the suspension was increased to 30%; the suspension feed rate was increased to 35 ml / min; and the ceramic layer thickness was 150 nm.

[0105] The thermal barrier coating prepared in this comparative example has a structure such as Figure 8 As shown, the higher solids content increases the viscosity of the suspension, making it more difficult to break. This also increases the total feed rate, resulting in insufficient melting. The lower Ar flow rate also leads to lower particle momentum, resulting in a highly porous coating. Compared to the composite thermal barrier coating of Example 2, the coating failed after only 40 water quenches, shortening its thermal shock life by approximately 85%.

[0106] Comparative Example 4

[0107] This comparative example is used to illustrate the thermal barrier coating and preparation method disclosed in the present invention, and includes the following steps:

[0108] Ni-based high-temperature alloy is used as the substrate;

[0109] The thermal insulation base layer was prepared by atmospheric plasma spraying of yttrium-stabilized zirconia powder. The spraying parameters were as follows: ion spraying current of 450-500A, spraying distance of 110-120mm; spray gun swing rate of 500-600mm / s; Ar gas flow rate of 30-35slpm; H2 flow rate of 6-8slpm; powder feeding amount of 1.9-2.2; and the thickness of the thermal insulation base layer was 300um.

[0110] The thermal barrier coating prepared in this comparative example has a lamellar structure. Compared with the composite structure thermal barrier coating of Example 1, the coating fails to peel off after only 150 water quenching cycles, and the thermal shock life is shortened by about 45%.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A thermal barrier coating, characterized in that: The invention comprises a thermal insulation bottom layer and a high strain tolerance layer, wherein the thermal insulation bottom layer is located below the high strain tolerance layer, the thermal insulation bottom layer comprises a lamellar yttrium-stabilized zirconia having stacked lamellar units, and the high strain tolerance layer comprises a high strain tolerance yttrium-stabilized zirconia, wherein the high strain tolerance yttrium-stabilized zirconia has one or more of a vertical crack structure, a columnar structure and a porous structure.

2. The thermal barrier coating according to claim 1, characterized in that The thickness of the thermal insulation bottom layer is 50-500 μm.

3. The thermal barrier coating according to claim 1, characterized in that In the thermal insulation bottom layer, the transverse major diameter of the sheet unit is 5-30 μm, and the longitudinal thickness is 2-10 μm.

4. The thermal barrier coating according to claim 1, characterized in that The porosity of the thermal insulation bottom layer is 5% to 25%.

5. The thermal barrier coating according to claim 1, characterized in that The thickness of the high strain tolerance layer is 60-300 μm.

6. The thermal barrier coating according to claim 1, characterized in that The vertical crack structure includes a plurality of cracks extending along the thickness direction of the high strain tolerance layer, the cracks have a depth of 60-300 μm, a width of 0.3-3 μm, and a density of 2-10 mm -1 .

7. The thermal barrier coating according to claim 1, characterized in that The columnar structure includes a plurality of columnar microstructures extending along the thickness direction of the high strain tolerance layer, the height of the columnar microstructure is 60-300 μm, and the density is 5-30 mm -1 .

8. The thermal barrier coating according to claim 1, characterized in that The porous structure includes a plurality of micropores formed inside the high strain tolerance layer, the pore diameter of the micropores is 0.5-5 μm, and the porosity of the porous structure is 25%-45%.

9. The thermal barrier coating according to claim 1, characterized in that It also includes a bonding layer, the bonding layer is located on a side of the thermal insulation base layer away from the high strain tolerance layer, the bonding layer includes MCrAlY or MCrAlTaY, wherein M is Ni and / or Co; The thickness of the adhesive layer is 50-200 μm.

10. A high temperature resistant component, characterized in that: The invention comprises a hot end component and a thermal barrier coating according to any one of claims 1 to 9, wherein the thermal barrier coating is arranged on the surface of the hot end component, and the hot end component comprises a turbine blade, a combustion chamber, a heat shield, a nozzle, a flame tube or a tail nozzle.

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