Method for post-processing thermal barrier coating

Abstract

The invention belongs to the technical field of aero-engine coatings, and relates to a thermal barrier coating post-treatment method, after a YSZ or rare earth zirconate thermal barrier coating is prepared on a base material and surface finishing is carried out, the bonding strength of the thermal barrier coating and the base material is improved through heat treatment, and the service life of the thermal barrier coating and the base material is prolonged through heat treatment. The method comprises the steps of high-temperature post-treatment, cleaning, dehydration and drying. High-temperature post-treatment process parameters are selected, specifically, the thermal barrier coating is put into a heat treatment furnace, the temperature is increased to 600 DEG C along with the furnace, the thermal barrier coating is put into an atmospheric environment, heat preservation is conducted for 30-90 min, then the thermal barrier coating is cooled to 400 DEG C along with the furnace, heat preservation is conducted for 30 min, then the thermal barrier coating is cooled to 200 DEG C along with the furnace, heat preservation is conducted for 30 min, then the thermal barrier coating is cooled to According to the post-treatment method for the thermal barrier coating, the coating can have more excellent binding force, meanwhile, the roughness of the coating can be kept, and finally the performance of the coating is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation engine coating materials and relates to a method for post-processing a thermal barrier coating. Background Art

[0002] At present, with the continuous improvement of the thrust and working efficiency of gas turbines, the gas intake temperature is getting higher and higher, and the working temperature of nickel-based high-temperature alloys used in turbine blades and other hot end components has gradually approached its service temperature limit. 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 and combines them with metal substrates in the form of coatings to increase the working temperature of metal parts, enhance the high temperature resistance of hot end components, extend the service life of hot end components, and improve the working efficiency of the engine. However, the long-term use of the next generation of high-performance aircraft engine thermal barrier coating materials still has problems with unstable life and foreign matter adhesion. Therefore, studying the post-treatment methods of thermal barrier coatings has become the key to developing thermal barrier coatings that can improve the performance of aircraft engines. Summary of the invention

[0003] The purpose of the present invention is to provide a method for post-treatment of thermal barrier coatings in view of the above-mentioned deficiencies in the prior art, and the purpose is to improve the mechanical properties of the thermal barrier coatings and improve the coating life through the post-treatment method.

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

[0005] A method for post-processing a thermal barrier coating is provided, wherein the post-processing method comprises:

[0006] The thermal barrier coating is placed in a heat treatment furnace, heated to 600±50℃, atmospheric environment, kept warm for 30-90min, cooled to 400±50℃, kept warm for 30±5min, cooled to 200±50℃, kept warm for 30±5min, cooled to room temperature, and removed from the thermal barrier coating after cooling to room temperature. The cooling rate at each stage is 5±1℃ / min.

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

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

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

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

[0011] The cleaning steps are as follows: soak the YSZ or rare earth zirconate thermal barrier coating in a 10±5% water-based cleaning agent for 30±5 minutes, and then soak 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: soak the thermal barrier coating in a 10±5% water-based cleaning agent for 30±5 minutes, then soak the thermal barrier coating in deionized water for 30±5 minutes, then take it out and put it in an oven, and dry it at 80±10° C. for 15±5 minutes.

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

[0015] The present invention has the following advantages and beneficial effects:

[0016] During the heat treatment process of the present invention, a 600-400-200°C multi-stage insulation method is adopted. Under atmospheric environmental conditions, by controlling the insulation time and the temperature of each stage, the stability of the thermal barrier coating is optimized, the bonding strength of the thermal barrier coating is improved, and ultimately the life of the coating is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions implemented in the present invention, the following is a brief explanation of the drawings required to be used in the examples of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

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

[0019] Figure 2 The coating bonding strength changes of Examples 1, 2, 3 and Comparative Example; Figure 2 It can be seen that the use of the 600-400-200°C multi-stage insulation method improves the coating bonding strength to more than 10 MPa. Compared with other embodiments, the comparative example changes the maximum insulation parameter, so the bonding strength is reduced.

[0020] Figure 3 The coating life changes of Examples 1, 2, 3 and the comparative example; Figure 3It can be seen that the use of 600-400-200°C multi-stage insulation method increases the coating life by more than 100 hours. Compared with other embodiments, the comparative example changes the maximum insulation parameter, so the coating life is reduced. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] The features of various aspects of the embodiments of the present invention will be described in detail below. In the following detailed description, many specific details are provided to provide a comprehensive understanding of the present invention. However, it is obvious to a person skilled in the art that the present invention can also be implemented without these specific details. The technical solution of the invention will be further described in detail below in conjunction with the embodiments:

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

[0024] ⑴. YSZ or rare earth zirconate thermal barrier coating: prepared by atmospheric plasma spraying or electron beam physical vapor deposition.

[0025] ⑵. Cleaning: Soak the post-processed thermal barrier coating in a 10% water-based cleaning agent for 30 minutes, and then soak the coating in deionized water for 30 minutes. The water-based cleaning agent is a degreasing agent with a pH of 7. The water-based cleaning agent is specifically an environmentally friendly water-based cleaning agent, a multi-purpose water-based cleaning agent or a strong water-based cleaning agent;

[0026] ⑶. Dehydration and drying: Soak the thermal barrier coating in an organic solvent for 10 minutes, then take it out and put it in an oven, and dry it at 80°C for 15 minutes. The organic solvent is acetone or ethanol with analytical purity.

[0027] Embodiment 1:

[0028] Heat treatment after coating: put the surface finishing thermal barrier coating into the heat treatment furnace, heat it up to 650℃, keep it in the atmosphere for 45 minutes, then cool it down to 450℃, keep it for 30 minutes, then cool it down to 250℃, keep it for 30 minutes, then cool it down to room temperature, take out the thermal barrier coating after cooling to room temperature. The thermal barrier coating is YSZ coating.

[0029] Embodiment 2:

[0030] Heat treatment after coating: put the surface finishing thermal barrier coating into the heat treatment furnace, heat it up to 600℃, keep it in the atmosphere for 60 minutes, then cool it down to 400℃, keep it for 30 minutes, then cool it down to 200℃, keep it for 30 minutes, then cool it down to room temperature, and take out the thermal barrier coating after cooling to room temperature. The thermal barrier coating is a rare earth zirconate coating.

[0031] Embodiment 3:

[0032] Heat treatment after coating: put the surface finishing thermal barrier coating into the heat treatment furnace, heat it up to 550℃, keep it in the atmosphere for 75 minutes, then cool it down to 350℃, keep it for 30 minutes, then cool it down to 150℃, keep it for 30 minutes, then cool it down to room temperature, and take out the thermal barrier coating after cooling to room temperature. The thermal barrier coating is a rare earth zirconate coating.

[0033] Comparative Example:

[0034] Heat treatment after coating: put the surface finishing thermal barrier coating into the heat treatment furnace, heat it up to 700℃, keep it in the atmosphere for 120 minutes, then cool it down to 500℃, keep it for 30 minutes, then cool it down to 300℃, keep it for 30 minutes, then cool it down to room temperature, and take out the thermal barrier coating after cooling to room temperature. The thermal barrier coating is a rare earth zirconate coating.

[0035] like Figure 2 The thermal barrier coating bonding strengths of Examples 1, 2, 3 and the comparative example are shown. Figure 3 The figure shows the change in the life of the thermal barrier coating of Examples 1, 2, 3 and the comparative example. It can be seen that due to the difference in the insulation temperature parameters and the insulation step design parameters, the coating bonding strength in the comparative example is only 45MPa and the life is. The combination of the insulation temperature parameters and the insulation step design parameters in Examples 1, 2 and 3 makes the coating bonding strength all above 60MPa. In the post-processing process of the embodiment of the present invention, a multi-stage insulation method is adopted: heating with the furnace to 600±50℃--insulating for 30-90min and then cooling with the furnace to 400±50℃, cooling with the furnace to 200±50℃ after 30min of insulation, and cooling with the furnace to room temperature after 30min of insulation. Under the condition of pumping, the insulation time and the temperature of each stage are controlled to achieve the improvement of the bonding strength and life of the thermal barrier coating. On the other hand, from Figure 2 It can also be seen that since the maximum insulation parameter is changed in the comparative example compared with Examples 1, 2, and 3 (the temperature is raised to 700° C. compared with other examples), it is found that the thermal barrier bonding strength and life are significantly reduced.

[0036] Under atmospheric conditions, a multi-stage insulation method of 600-400-200℃ is adopted. By controlling the insulation time and the temperature of each stage, the integrity of the thermal barrier coating can be maintained, the bonding strength of the thermal barrier coating can be increased to 60MPa, and ultimately the coating life can be increased 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 technician familiar with the field can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A method for post-treatment of a thermal barrier coating, characterized in that: The heat treatment process is as follows: The thermal barrier coating is loaded into a heat treatment furnace, heated to 600±50℃ with the furnace, atmospheric environment, kept warm for 30-90min, then cooled to 400±50℃ with the furnace, kept warm for 30±5min, then cooled to 200±50℃ with the furnace, kept warm for 30±5min, then cooled to room temperature with the furnace, and the thermal barrier coating is taken out after cooling to room temperature.

2. The post-processing method according to claim 1, characterized in that: The coating system is YSZ or rare earth zirconate thermal barrier coating.

3. The post-processing method according to claim 1, characterized in that: The matrix material is a nickel-based high-temperature alloy material.

4. The post-processing method according to claim 1, characterized in that: The method for preparing the YSZ or rare earth zirconate thermal barrier coating on the base material is: atmospheric plasma spraying or electron beam physical vapor deposition method.

5. The post-processing method according to claim 1, characterized in that: The cooling rate in each stage is 5±1℃ / min.

6. The heat treatment method according to claim 1, characterized in that: The post-treatment method further comprises the steps of cleaning and dehydrating and drying the coating after the heat treatment.

7. The post-processing method according to claim 5, characterized in that: The cleaning steps are as follows: soak the thermal barrier coating in a 10±5% water-based cleaning agent for 30±5 minutes, and then soak the thermal barrier coating in deionized water for 30±5 minutes.

8. The post-processing method according to claim 6, characterized in that: The water-based cleaning agent is a degreasing agent with a pH of 7±0.

5.

9. The post-processing method according to claim 5, characterized in that: The dehydration and drying steps are as follows: soak the thermal barrier coating in an organic solvent for 10±5 minutes, then take it out and put it in an oven, and dry it at 80±10° C. for 15±5 minutes.

10. The post-processing method according to claim 9, characterized in that: The organic solvent is acetone or ethanol, and its purity is analytical grade.

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