A method of thermal barrier coating post-processing

Abstract

This invention belongs to the field of aero-engine coating technology and relates to a method for post-treatment of thermal barrier coatings. After preparing a YSZ or rare-earth zirconate thermal barrier coating and surface finishing on a substrate material, heat treatment is used to improve the bonding strength and lifespan between the thermal barrier coating and the substrate material. The method includes high-temperature post-treatment and cleaning, dehydration, and drying steps. The high-temperature post-treatment process parameters are as follows: The material is placed in a heat treatment furnace, heated to 600°C in an atmospheric environment, held for 30-90 minutes, then cooled to 400°C in the furnace, held for 30 minutes, then cooled to 200°C in the furnace, held for 30 minutes, and then cooled to room temperature in the furnace. After cooling to room temperature, the thermal barrier coating is removed. This post-treatment method for thermal barrier coatings results in a coating with superior adhesion while maintaining the coating's roughness, ultimately improving the coating's performance.

Description

Technical Field

[0001] This invention belongs to the technical field of aero-engine coating materials, and relates to a method for post-treatment of thermal barrier coatings. Background Technology

[0002] Currently, with the continuous improvement of gas turbine thrust and efficiency, the gas inlet temperature is also increasing, and the operating temperature of nickel-based superalloys used in turbine blades and other hot-end components is gradually approaching their operating temperature limits. Thermal barrier coatings (TBCs) are a surface protection technology that utilizes the high-temperature resistance, erosion resistance, corrosion resistance, and low thermal conductivity of ceramic materials, combining them with a metal substrate in the form of a coating. This aims to increase the operating temperature of metal components, enhance the high-temperature resistance of hot-end components, extend the service life of hot-end components, and improve engine efficiency. However, the long-term use of next-generation high-performance aero-engine thermal barrier coating materials still faces problems such as unstable service life and foreign matter adhesion. Therefore, researching post-treatment methods for thermal barrier coatings has become crucial for developing technologies that can improve the performance of aero-engine thermal barrier coatings. Summary of the Invention

[0003] The purpose of this invention is to provide a post-treatment method for thermal barrier coatings to address the shortcomings of the prior art. The aim of this post-treatment method is to improve the mechanical properties of the thermal barrier coating and enhance its lifespan.

[0004] To solve this technical problem, the technical solution of the present invention is as follows:

[0005] A method for post-treatment of thermal barrier coatings is provided, the post-treatment method comprising the following steps:

[0006] The thermal barrier coating was placed in a heat treatment furnace and heated to 600±50℃ in an atmospheric environment. After holding at this temperature for 30-90 minutes, the furnace was cooled to 400±50℃, held for 30±5 minutes, and then cooled to 200±50℃. After holding at this temperature for another 30±5 minutes, the furnace was cooled to room temperature. The thermal barrier coating was then removed from the furnace after reaching room temperature. The cooling rate at each stage was 5±1℃ / min.

[0007] The coating system is a YSZ or rare earth zirconate thermal barrier coating.

[0008] The matrix material is a nickel-based high-temperature alloy.

[0009] The coating preparation method is atmospheric plasma spraying and electron beam physical vapor deposition.

[0010] The method further includes the steps of cleaning and dehydrating the coating after post-treatment.

[0011] The cleaning steps are as follows: Immerse the YSZ or rare earth zirconate thermal barrier coating in 10±5% water-based cleaning agent for 30±5 minutes, and then immerse the thermal barrier coating in deionized water for 30±5 minutes.

[0012] Preferably, the water-based cleaning agent is a degreasing agent with a pH of 7±0.5.

[0013] The dehydration and drying steps are as follows: The thermal barrier coating is immersed in 10±5% water-based cleaning agent for 30±5 minutes, and then immersed in deionized water for 30±5 minutes. Then it is taken out and placed in an oven to dry at 80±10℃ for 15±5 minutes.

[0014] Preferably, the organic solvent is acetone or ethanol, and its purity is analytical grade.

[0015] The advantages and beneficial effects of this invention are as follows:

[0016] In the heat treatment process of this invention, a multi-stage heat preservation method of 600-400-200℃ is adopted. Under atmospheric conditions, by controlling the heat preservation time and temperature at each stage, the stability of the thermal barrier coating is optimized, the bonding strength of the thermal barrier coating is improved, and the life of the coating is ultimately improved. Attached Figure Description

[0017] To more clearly illustrate the technical solutions implemented in this invention, the accompanying drawings used in the embodiments of this invention will be briefly explained below. Obviously, the drawings described below are merely some embodiments of this invention. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0018] Figure 1 The changes in the appearance of the thermal barrier coating before and after post-treatment in Example 1 are shown in Figures (a) and (b), respectively; from Figure 1 As can be seen from the image, the coating appears yellowish-white after the thermal barrier coating is applied, indicating that the coating is uniform.

[0019] Figure 2 The coating bond strength changes in Examples 1, 2, 3, and the comparative examples; from Figure 2 As can be seen, the multi-segment insulation method of 600-400-200℃ improved the coating bonding strength to over 10MPa. The comparative example changed the maximum insulation parameter compared to other embodiments, thus reducing the bonding strength.

[0020] Figure 3 The coating lifetime changes for Examples 1, 2, 3, and the comparative examples; from Figure 3As can be seen, the multi-stage insulation method of 600-400-200℃ increases the coating life by more than 100 hours. The comparative example changed the maximum insulation parameter compared with other embodiments, thus reducing the coating life. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The features of various aspects of the embodiments of the present invention will now be described in detail. In the following detailed description, many specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can also be practiced without these specific details. The technical solutions of the invention will be further described in detail below with reference to embodiments:

[0023] The process conditions for the washing and dehydration drying steps in this embodiment of the invention are the same as those in the comparative example, and the steps are as follows:

[0024] (1) YSZ or rare earth zirconate thermal barrier coating: prepared by atmospheric plasma spraying or electron beam physical vapor deposition.

[0025] (2) Cleaning: Immerse the post-treatment thermal barrier coating in a 10% water-based cleaning agent for 30 minutes, then immerse the coating in deionized water for 30 minutes. The water-based cleaning agent is a degreasing agent with a pH of 7, specifically an environmentally friendly water-based cleaning agent, a multi-purpose water-based cleaning agent, or a powerful water-based cleaning agent.

[0026] (3) Dehydration and drying: Immerse the thermal barrier coating in an organic solvent for 10 minutes, then remove it and place it in an oven to dry at 80°C for 15 minutes. The organic solvent is acetone or ethanol, and the purity is analytical grade.

[0027] Example 1:

[0028] Post-coating heat treatment: The surface-finished thermal barrier coating is placed in a heat treatment furnace and heated to 650°C in an atmospheric environment. After holding at this temperature for 45 minutes, the temperature is cooled to 450°C and held for 30 minutes. Then, the temperature is cooled to 250°C and held for 30 minutes. Finally, the temperature is cooled to room temperature, and the thermal barrier coating is removed after cooling to room temperature. The thermal barrier coating is a YSZ coating.

[0029] Example 2:

[0030] Post-coating heat treatment: The surface-finished thermal barrier coating is placed in a heat treatment furnace and heated to 600°C in an atmospheric environment. After holding at this temperature for 60 minutes, the temperature is cooled to 400°C and held for 30 minutes. Then, the temperature is cooled to 200°C and held for 30 minutes. Finally, the temperature is cooled to room temperature, and the thermal barrier coating is removed after cooling to room temperature. The thermal barrier coating is a rare earth zirconate coating.

[0031] Example 3:

[0032] Post-coating heat treatment: The surface-finished thermal barrier coating is placed in a heat treatment furnace and heated to 550°C in an atmospheric environment. After holding at this temperature for 75 minutes, the temperature is cooled to 350°C and held for 30 minutes. Then, the temperature is cooled to 150°C and held for 30 minutes. Finally, the temperature is cooled to room temperature, and the thermal barrier coating is removed after cooling to room temperature. The thermal barrier coating is a rare earth zirconate coating.

[0033] Comparative example:

[0034] Post-coating heat treatment: The surface-finished thermal barrier coating is placed in a heat treatment furnace and heated to 700°C in an atmospheric environment. After holding at this temperature for 120 minutes, the temperature is cooled to 500°C and held for 30 minutes. Then, the temperature is cooled to 300°C and held for 30 minutes before being cooled to room temperature. The thermal barrier coating is then removed from the furnace. The thermal barrier coating is a rare earth zirconate coating.

[0035] like Figure 2 The figures show the bonding strength of the thermal barrier coatings in Examples 1, 2, 3, and the comparative examples. Figure 3 The figures show the changes in the thermal barrier coating lifespan of Examples 1, 2, 3, and the comparative example. It can be seen that due to differences in the insulation temperature parameters and the insulation step design parameters, the coating bonding strength in the comparative example is only 45 MPa, and the lifespan is [not specified]. However, the combination of insulation temperature and insulation step design parameters in Examples 1, 2, and 3 results in coating bonding strengths exceeding 60 MPa. In the post-processing of this invention, a multi-stage insulation method is used: heating to 600±50℃ in the furnace, holding for 30-90 minutes, then cooling to 400±50℃ in the furnace, holding for 30 minutes, then cooling to 200±50℃ in the furnace, and holding for 30 minutes before cooling to room temperature in the furnace. Under aeration conditions, by controlling the insulation time and temperature at each stage, the bonding strength and lifespan of the thermal barrier coating are improved. On the other hand, from [the following text is incomplete and requires further context: "From..."] Figure 2 It can also be seen that, due to the change in the maximum insulation parameter compared to Examples 1, 2, and 3 (the temperature was raised to 700°C compared to other examples), the thermal barrier bonding strength and lifespan were significantly reduced.

[0036] Under atmospheric conditions, a multi-stage heat preservation method of 600-400-200℃ is adopted. By controlling the heat preservation time and temperature at each stage, the integrity of the thermal barrier coating can be maintained, the bonding strength of the thermal barrier coating can be improved to 60MPa, and the coating life can be improved to 600 hours.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A method for post-treatment of thermal barrier coatings, characterized in that: The method process is as follows: The thermal barrier coating is loaded into a heat treatment furnace and heated to 600°C. At 50℃ in an atmospheric environment, hold for 30-90 minutes, then cool with the furnace to 400℃. 50℃, keep warm for 30 minutes After 5 minutes, cool with the furnace to 200°C. 50℃, keep warm for 30 minutes After 5 minutes, the furnace was cooled to room temperature. Once cooled to room temperature, the thermal barrier coating was removed. The cooling rate for each stage was 5. 1℃ / min; The entire process is carried out under atmospheric conditions, using a multi-stage heat preservation method. By controlling the heat preservation time and temperature at each stage, the integrity of the thermal barrier coating can be maintained, the bonding strength of the thermal barrier coating can be increased to over 60MPa, and the coating life can be improved. The coating system is a YSZ or rare earth zirconate thermal barrier coating. The base material is a nickel-based high-temperature alloy.

2. The method according to claim 1, characterized in that: The method for preparing YSZ or rare earth zirconate thermal barrier coatings on the substrate material is: atmospheric plasma spraying or electron beam physical vapor deposition.

3. The method according to claim 1, characterized in that: The method further includes the steps of cleaning and dehydrating the coating after heat treatment.

4. The method according to claim 3, characterized in that: The cleaning steps are as follows: Immerse the thermal barrier coating in 10... Clean 30 minutes in 5% water-based cleaning agent After 5 minutes, the thermal barrier coating is immersed in deionized water for 30 minutes. 5 minutes.

5. The method according to claim 4, characterized in that: Water-based cleaning agents have a pH of 7. 0.5% degreasing agent.

6. The method according to claim 3, characterized in that: The dehydration and drying steps are as follows: The thermal barrier coating is immersed in an organic solvent for 10 minutes. 5 minutes, then remove and place in an oven at 80°C. Dry at 10℃ for 15 minutes 5 minutes.

7. The method according to claim 6, characterized in that: The organic solvent is acetone or ethanol, and its purity is analytical grade.

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