Long-life double-ceramic-layer thermal barrier coating and preparation method thereof
By preparing the YSZ/GYYSZ dual-ceramic thermal barrier coating, the problem of thermal barrier coating cracking at high temperatures is solved by using the porosity and thermal expansion coefficient gradient dispersion stress, and the long life and high temperature stability of the coating are achieved. The preparation process is simple and mature.
Patent Information
- Application Number
- CN202510607308.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-13
- Publication Date
- 2025-08-08
AI Technical Summary
The existing thermal barrier coatings crack and fail due to material phase change and thermal expansion coefficient differences at high temperatures, affecting their high-temperature applications.
The YSZ/GYYSZ dual ceramic layer thermal barrier coating was prepared by atmospheric plasma spraying technology. By regulating the porosity gradient and the thermal expansion coefficient gradient dispersion stress, it combined with the intermediate layer of the metastable quadrangular structure and the surface ceramic layer of the cubic structure to form a tight connection.
The high temperature stability and life of the coating are significantly improved. The structure is intact after 300 thermal cycles of 1150°C and the structure is ineffective after 390 times. Compared with the single YSZ ceramic layer, the life of the single YSZ ceramic layer is increased by 102%, and the single GYYSZ ceramic layer is increased by 162%, and the preparation process is simple and mature.
Smart Images
Figure CN120443096A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of thermal barrier coatings, and in particular relates to a long-life double-ceramic layer thermal barrier coating and a preparation method thereof. Background Art
[0002] Thermal barrier coatings (TBCs) are primarily used to protect high-temperature components in gas turbines by isolating high-temperature gases and reducing heat transfer, thereby improving thermal efficiency. 8% yttria-stabilized zirconia (8YSZ) is a widely used TBC material due to its low thermal conductivity and excellent thermal shock resistance. However, at temperatures exceeding 1200°C, 8YSZ transforms from a metastable tetragonal phase (t' phase) to a monoclinic phase (m phase), accompanied by a volume change of approximately 4%. This increases internal stress in the coating, leading to cracking and spalling, and restricts its high-temperature application. To improve the high-temperature performance of 8YSZ, it has been modified by doping with rare earth oxides. For example, Yb2O3-Gd2O3 co-doped GYYSZ exhibits higher phase stability and lower thermal conductivity. However, its low thermal expansion coefficient, significantly different from that of the metal substrate and the bond coat, can easily generate interlaminar stresses at high temperatures, leading to coating failure.
[0003] To address this issue, a YSZ transition layer is typically introduced between the GYYSZ and bond coats. This creates a gradient in the thermal expansion coefficient (CTE) to disperse stress and extend the coating's life. Furthermore, coating porosity significantly influences the CTE and thermal stress distribution. By manipulating the porosity, a gradient CTE distribution can be achieved, thereby reducing thermal stress concentration at high temperatures and minimizing the risk of coating cracking. Summary of the Invention
[0004] To solve the above problems and / or defects, the main purpose of the present invention is to provide a long-life dual-ceramic layer thermal barrier coating, which has a porosity gradient YSZ / GYYSZ dual-ceramic layer thermal barrier coating to optimize high temperature performance.
[0005] Another object of the present invention is to provide a method for preparing the long-life dual-ceramic layer thermal barrier coating, which is prepared by controlling the spraying process parameters, has a simple process and high process maturity.
[0006] To achieve the above object, the present invention adopts the following technical solutions:
[0007] A first aspect of the present invention provides a method for preparing a long-life dual-ceramic layer thermal barrier coating, comprising the following steps:
[0008] (1) Pre-treating the substrate, and then preparing a bonding layer on the treated substrate using an atmospheric plasma spraying process;
[0009] (2) preparing an intermediate ceramic layer on the bonding layer using an atmospheric plasma spraying process;
[0010] (3) preparing a surface ceramic layer on the intermediate ceramic layer by an atmospheric plasma spraying process;
[0011] The substrate is Inconel 718 nickel-based high-temperature alloy.
[0012] Preferably, in step (1), the pretreatment includes sandblasting the surface of the substrate, and ultrasonically cleaning the substrate after sandblasting in an ethanol solution.
[0013] Preferably, in step (1), the bonding layer powder is sprayed onto the substrate using an atmospheric plasma spraying process to obtain the bonding layer, which has a thickness of 100-120 μm.
[0014] Preferably, in step (1), the atmospheric plasma spraying process of the bonding layer includes: current of 600A, argon flow rate of 46L / min, hydrogen flow rate of 6L / min, powder feeding rate of 29g / min, carrier gas flow rate of 3.5L / min, auxiliary gas flow rate of 2L / min, gun speed of 1000mm / s, and spraying distance of 90mm.
[0015] More preferably, in step (1), the bonding layer powder is NiCrAlY of Oerlikon Metco Amdry 962, which has the composition of Ni 22 Cr 10 Al 1.0 Y.
[0016] Preferably, in step (2), an atmospheric plasma spraying process is used to spray the intermediate layer powder on the bonding layer to prepare a first intermediate layer, then spray the second intermediate layer on the first intermediate layer to prepare a second intermediate layer, and then spray the third intermediate layer on the second intermediate layer, and the thickness of each layer is 50-60 μm.
[0017] More preferably, in step (2), the atmospheric plasma spraying process of the intermediate ceramic layer includes: current of 600A, argon flow rate of 40L / min, hydrogen flow rate of 8L / min, powder feeding rate of 40g / min, carrier gas flow rate of 3L / min, auxiliary gas flow rate of 2L / min, gun speed of 1000mm / s, spraying distance of 90-120mm, and the spraying distances of the first intermediate layer, the second intermediate layer and the third intermediate layer are different.
[0018] More preferably, in step (2), the intermediate layer powder is ZrO2-8Y2O3 (8YSZ) of Oerlikon Metco 204NS brand, and the particle size distribution is between 30-70 μm.
[0019] Preferably, in step (3), the surface powder is sprayed on the intermediate layer by an atmospheric plasma spraying process to prepare a surface ceramic layer with a thickness of 120-150 μm.
[0020] Preferably, in step (3), the surface powder is ZrO2-9.5Y2O3-5.6Yb2O3-5.2Gd2O3 (GYYSZ) of Oerlikon Metco 206A brand, and the particle size distribution is between 45-120 μm.
[0021] Preferably, in step (3), the atmospheric plasma spraying process of the surface ceramic layer includes: current of 600A, argon flow rate of 58L / min, hydrogen flow rate of 16L / min, powder feeding rate of 53g / min, carrier gas flow rate of 3L / min, auxiliary gas flow rate of 2L / min, gun speed of 1000mm / s, and spraying distance of 70mm.
[0022] A second aspect of the present invention provides a long-life dual-ceramic-layer thermal barrier coating, which is prepared by any of the aforementioned methods for preparing a long-life dual-ceramic-layer thermal barrier coating.
[0023] Compared with the prior art, the present invention has the following beneficial effects:
[0024] 1. The present invention proposes a long-life dual-ceramic layer thermal barrier coating to achieve a long life of the thermal barrier coating. The porosity of the intermediate layer is adjusted by only changing the spraying distance. The operation is simple and the preparation difficulty is low. The thermal expansion coefficient of the intermediate layer is adjusted by using intermediate layers with different porosities to reduce the thermal mismatch stress of the coating.
[0025] 2. The intermediate ceramic layer of the present invention has a metastable tetragonal structure (t'), offering excellent thermal stability and closely connecting the intermediate layers of varying porosity. The surface ceramic layer has a cubic structure (C), offering excellent thermal stability and closely connecting the intermediate layers. The resulting thermal barrier coating remained structurally intact after 300 thermal cycles at 1150°C under thermal shock and water quenching conditions, and failed after 390 thermal cycles. This represents a lifespan improvement of approximately 102% compared to a single YSZ ceramic layer and approximately 162% compared to a single GYYSZ ceramic layer. Furthermore, the long-life dual-ceramic-layer thermal barrier coating of the present invention boasts advantages such as a simple preparation process and high process maturity, promising promising engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 This is a process flow chart for preparing the long-life dual-ceramic layer thermal barrier coating of the present invention.
[0027] Figure 2 This is a microscopic morphology of the cross section of the long-life dual-ceramic layer thermal barrier coating prepared in Example 1.
[0028] Figure 3This is a partial pore structure diagram of the ceramic layer of the cross section of the long-life dual-ceramic layer thermal barrier coating prepared in Example 1.
[0029] Figure 4 This is a microscopic morphology of the cross section of the 8YSZ single ceramic layer thermal barrier coating prepared in Comparative Example 1.
[0030] Figure 5 This is a microscopic morphology of the cross section of the GYYSZ single ceramic layer thermal barrier coating prepared in Comparative Example 2.
[0031] Figure 6 These are photos of the various stages of thermal shock and water quenching of the long-life dual-ceramic layer thermal barrier coating prepared in Example 1.
[0032] Figure 7 These are photos of the various stages of thermal shock and water quenching of the 8YSZ single ceramic layer thermal barrier coating prepared in Comparative Example 1.
[0033] Figure 8 These are photos of the various stages of thermal shock and water quenching of the GYYSZ single ceramic layer thermal barrier coating prepared in Comparative Example 2.
[0034] Figure 9 This is a cross-sectional microscopic morphology of the long-life dual-ceramic layer thermal barrier coating prepared in Example 1 after thermal shock and water quenching.
[0035] Figure 10 This is the cross-sectional micromorphology of the 8YSZ single ceramic layer thermal barrier coating prepared in Comparative Example 1 after thermal shock and water quenching.
[0036] Figure 11 This is the cross-sectional micromorphology of the GYYSZ single ceramic layer thermal barrier coating prepared in Comparative Example 2 after thermal shock and water quenching. DETAILED DESCRIPTION
[0037] In order to more fully understand and demonstrate the technical solutions, objectives, and advantages of the present invention, the following is a further detailed and complete description of the technical effects produced by the present invention in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some of the embodiments of the present invention, and not all of them. It should be pointed out that for those skilled in the art, other embodiments obtained without departing from the concept of the present invention are all within the scope of protection of the present invention.
[0038] Figure 1 This is a flow chart of the preparation process for the long-life dual-ceramic layer thermal barrier coating of the present invention. The process control system controls the powder conveying system, plasma spray gun, and robotic arm; the robotic arm controls the movement speed and spraying distance of the plasma spray gun; the powder conveying system controls the powder feeding rate, feeding the powder to be sprayed into the plasma flame; after being fed into the plasma flame, the powder is heated, melted, and accelerated, and then sprayed onto the surface of the substrate material to form a coating.
[0039] Example 1
[0040] This embodiment provides a long-life dual-ceramic-layer thermal barrier coating, comprising:
[0041] Bond layer: The bonding layer powder was sprayed onto the Inconel 718 nickel-based superalloy substrate using an atmospheric plasma spraying process to a thickness of approximately 110 μm. The substrate had a diameter of 25 mm and a thickness of 5 mm. Before spraying, the surface was sandblasted and then ultrasonically cleaned in an ethanol solution to remove surface particles and oil. The bonding layer powder was Oerlikon MetcoAmdry962 NiCrAlY. The specific parameters are shown in Table 1. The specific composition of the Inconel 718 nickel-based superalloy substrate is shown in Table 2. The atmospheric plasma spraying process parameters are shown in Table 3.
[0042] Table 1
[0043] element Ni Cr Al Y Other Content (wt.%) Bal. 21.0-23.0 9.0-11.0 0.8-1.2 ＜1.0
[0044] Table 2
[0045]
[0046] Table 3
[0047]
[0048] Intermediate layer: The first intermediate layer powder is sprayed on the bonding layer using an atmospheric plasma spraying process with a thickness of about 50 μm; the second intermediate layer is sprayed on the first intermediate layer with a thickness of about 50 μm; the third intermediate layer is sprayed on the second intermediate layer with a thickness of about 50 μm; the atmospheric plasma spraying process is shown in Table 4.
[0049] Table 4
[0050]
[0051] Surface ceramic layer: Ceramic powder is sprayed on the third intermediate layer using an atmospheric plasma spraying process. The thickness is about 120 μm. The atmospheric plasma spraying process parameters are shown in Table 5.
[0052] Table 5
[0053]
[0054] Cross-sectional micromorphology: The polished sample was placed in a scanning electron microscope for observation. The selected scanning electron microscope model was S-3400N. The cross-sectional micromorphology of the long-life double-ceramic layer thermal barrier coating prepared in Example 1 is as follows: Figure 2As shown, the coating is tightly integrated as a whole, including a surface ceramic layer, an intermediate layer and a bonding layer, with thicknesses of approximately 120 μm, 150 μm and 110 μm, respectively.
[0055] Pore structure of the cross-section ceramic layer: COMSOL multi-physics simulation software and Image J image analysis software are used to extract the pores and calculate the porosity, such as Figure 3 As shown, the porosity of the ceramic layer of the long-life dual-ceramic-layer thermal barrier coating prepared in Example 1 is 21.3%.
[0056] Comparative Example 1
[0057] This comparative example proposes an 8YSZ single ceramic layer thermal barrier coating, comprising:
[0058] Bonding layer: The bonding layer powder was sprayed onto the Inconel 718 nickel-based superalloy substrate using an atmospheric plasma spraying process, with a thickness of approximately 120 μm. The substrate had a diameter of 25 mm and a thickness of 5 mm. Before spraying, the surface was sandblasted and then ultrasonically cleaned in an ethanol solution to remove surface particles and oil. The bonding layer powder was Oerlikon MetcoAmdry962 NiCrAlY. The specific parameters are shown in Table 1. The specific composition of the Inconel 718 nickel-based superalloy substrate is shown in Table 2. The atmospheric plasma spraying process parameters are shown in Table 3.
[0059] Ceramic layer (8YSZ): The ceramic powder was sprayed onto the bonding layer using an atmospheric plasma spraying process, with a thickness of approximately 270 μm. The atmospheric plasma process is shown in the third intermediate layer in Table 4.
[0060] The microscopic morphology of the cross section of the 8YSZ single ceramic layer thermal barrier coating prepared in this comparative example is as follows: Figure 4 shown.
[0061] Comparative Example 2
[0062] This comparative example proposes a GYYSZ single ceramic layer thermal barrier coating, comprising:
[0063] Bond layer: The bonding layer powder was sprayed onto the Inconel 718 nickel-based superalloy substrate using an atmospheric plasma spraying process to a thickness of approximately 110 μm. The substrate had a diameter of 25 mm and a thickness of 5 mm. Before spraying, the surface was sandblasted and then ultrasonically cleaned in an ethanol solution to remove surface particles and oil. The bonding layer powder was Oerlikon MetcoAmdry962 NiCrAlY. The specific parameters are shown in Table 1. The specific composition of the Inconel 718 nickel-based superalloy substrate is shown in Table 2. The atmospheric plasma spraying process parameters are shown in Table 3.
[0064] Ceramic layer (GYYSZ): The ceramic layer powder is sprayed on the bonding layer using an atmospheric plasma spraying process. The thickness is about 270 μm. The atmospheric plasma spraying process parameters are shown in Table 5.
[0065] The microscopic morphology of the cross section of the GYYSZ single ceramic layer thermal barrier coating prepared in this comparative example is as follows: Figure 5 shown.
[0066] Thermal shock and water quenching experiment: The instrument used is the annealing heat treatment atmosphere furnace produced by Nabertherm, model N61 / H. During the experiment, the annealing heat treatment atmosphere furnace is preheated to 1150℃, and then the sample is placed in the annealing heat treatment atmosphere furnace and kept warm for 5 minutes. After keeping warm, the sample is taken out and placed in deionized water to cool to room temperature. After drying, a second cycle is performed. This cycle is repeated until the coating falls off and fails.
[0067] Thermal shock and water quenching tests were conducted on three samples of the long-life dual-ceramic thermal barrier coating prepared in Example 1, the 8YSZ single-ceramic thermal barrier coating prepared in Comparative Example 1, and the GYYSZ single-ceramic thermal barrier coating prepared in Comparative Example 2. The results are as follows:
[0068] The long-life dual-ceramic layer thermal barrier coating prepared in Example 1 remained intact after 300 thermal shock and water quenching tests. The three samples failed due to large-scale coating shedding at the 380th, 390th, and 390th tests, respectively. The surface images at each stage are shown in Figure 2. Figure 6 shown.
[0069] The 8YSZ single ceramic layer thermal barrier coating prepared in comparative example 1 began to fall off slightly after 100 thermal shock and water quenching tests. The three samples failed at the 193rd, 234th, and 266th times, respectively. The surface pictures at each stage are as follows: Figure 7 shown.
[0070] The GYYSZ single ceramic layer thermal barrier coating prepared in comparative example 2 began to fall off slightly after 50 thermal shock and water quenching tests. The three samples failed at the 149th, 172nd and 175th times respectively. The surface pictures at each stage are as follows: Figure 8 shown.
[0071] The long-life dual-layer thermal barrier coating prepared in Example 1 maintained its internal intermediate ceramic structure even after failure. The cross-sectional micromorphology after thermal shock and water quenching is shown in Figure 9. Cracking and shedding of the coating occurred in the surface ceramic layer. The 8YSZ single-layer thermal barrier coating prepared in Comparative Example 1 exhibited severe cracking in its internal ceramic layer after failure. The cross-sectional micromorphology after thermal shock and water quenching is shown in Figure 10. The GYYSZ single-layer thermal barrier coating prepared in Comparative Example 2 exhibited severe cracking in its internal ceramic layer after failure. The cross-sectional micromorphology after thermal shock and water quenching is shown in Figure 11.
[0072] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.
Claims
1. A method for preparing a long-life dual-ceramic layer thermal barrier coating, characterized in that: The following steps are involved: (1) Pre-treating the substrate, and then preparing a bonding layer on the treated substrate using an atmospheric plasma spraying process; (2) preparing an intermediate ceramic layer on the bonding layer using an atmospheric plasma spraying process; (3) preparing a surface ceramic layer on the intermediate ceramic layer by an atmospheric plasma spraying process; The substrate is Inconel 718 nickel-based high-temperature alloy.
2. The method for preparing a long-life dual-ceramic layer thermal barrier coating according to claim 1, characterized in that: In step (1), the pretreatment includes sandblasting the surface of the substrate, and ultrasonically cleaning the substrate after sandblasting in an ethanol solution.
3. The method for preparing a long-life dual-ceramic layer thermal barrier coating according to claim 1, characterized in that: In step (1), the bonding layer powder is sprayed on the substrate by an atmospheric plasma spraying process to obtain the bonding layer with a thickness of 100-120 μm.
4. The method for preparing a long-life dual-ceramic layer thermal barrier coating according to claim 3, characterized in that: In step (1), the atmospheric plasma spraying process of the bonding layer includes: current of 600A, argon flow rate of 46L / min, hydrogen flow rate of 6L / min, powder feeding rate of 29g / min, carrier gas flow rate of 3.5L / min, auxiliary gas flow rate of 2L / min, gun speed of 1000mm / s, and spraying distance of 90mm.
5. The method for preparing a long-life dual-ceramic layer thermal barrier coating according to claim 3, characterized in that: In step (1), the bonding layer powder is Oerlikon Metco Amdry 962 brand NiCrAlY, which has the following composition: Ni 22 Cr 10 Al 1.0 Y.
6. The method for preparing a long-life dual-ceramic layer thermal barrier coating according to claim 1, characterized in that: In step (2), an atmospheric plasma spraying process is used to spray the intermediate layer powder on the bonding layer to prepare a first intermediate layer, then spray the second intermediate layer on the first intermediate layer to prepare a second intermediate layer, and spray the third intermediate layer on the second intermediate layer, with each layer having a thickness of 50-60 μm.
7. The method for preparing a long-life dual-ceramic layer thermal barrier coating according to claim 6, characterized in that: In step (2), the atmospheric plasma spraying process of the intermediate ceramic layer includes: current of 600A, argon flow rate of 40L / min, hydrogen flow rate of 8L / min, powder feeding rate of 40g / min, carrier gas flow rate of 3L / min, auxiliary gas flow rate of 2L / min, gun speed of 1000mm / s, spraying distance of 90-120mm, and the spraying distances of the first intermediate layer, the second intermediate layer and the third intermediate layer are different; The intermediate layer powder is ZrO2-8Y2O3 (8YSZ) of the Oerlikon Metco 204NS brand, and the particle size distribution is between 30-70 μm.
8. The method for preparing a long-life dual-ceramic layer thermal barrier coating according to claim 1, characterized in that: In step (3), the surface powder is sprayed on the intermediate layer by an atmospheric plasma spraying process to prepare a surface ceramic layer with a thickness of 120-150 μm.
9. The method for preparing a long-life dual-ceramic layer thermal barrier coating according to claim 8, characterized in that: In step (3), the atmospheric plasma spraying process of the surface ceramic layer includes: current of 600A, argon flow rate of 58L / min, hydrogen flow rate of 16L / min, powder feeding rate of 53g / min, carrier gas flow rate of 3L / min, auxiliary gas flow rate of 2L / min, gun speed of 1000mm / s, and spraying distance of 70mm; the surface powder is Oerlikon Metco 206A brand ZrO2-9.5Y2O3-5.6Yb2O3-5.2Gd2O3 (GYYSZ), and the particle size distribution is between 45-120μm.
10. A long-life dual-ceramic layer thermal barrier coating, characterized in that: The long-life dual-ceramic-layer thermal barrier coating is prepared by the preparation method of any one of claims 1 to 9.