Method for reducing surface roughness of ceramic layer of thermal barrier coating

Abstract

The invention belongs to the technical field of aero-engine coatings, and relates to a method for reducing the surface roughness of a thermal barrier coating ceramic layer, after the thermal barrier coating ceramic layer is prepared, the surface roughness of the ceramic layer must be reduced through surface treatment so as to reduce the adhesion of foreign objects on the surface of the ceramic layer. The method comprises the steps of polishing, cleaning and drying. And surface treatment process parameters are selected, specifically, abrasive materials are added into a working cabin of a dragging type polishing machine, the workpiece with the coating is hung on a tool, the main frequency of the dragging type polishing machine is set to be 30 + / -15 Hz, the total surface polishing time is 30 + / -15 Hz, the total surface polishing time is 30 + / -15 min, the forward rotation time is 60 + / -30 s, and the reverse rotation time is 60 + / -30 s. And the equipment is started for surface finishing treatment. According to the method for reducing the surface roughness, the wettability of the surface of the thermal barrier coating ceramic layer is improved, the coating has more excellent foreign object adhesion resistance, and finally the performance of the material is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation engine coatings and relates to a surface treatment method for a thermal barrier coating ceramic layer, in particular to a method for reducing the surface roughness of a thermal barrier coating ceramic layer. Background Art

[0002] Thermal barrier coatings generally consist of a metal bond layer, a thermally grown oxide, and an oxide ceramic layer, with the ceramic layer serving as the surface layer, providing thermal insulation for metal / engine components. In practical applications, high-temperature environments not only place high demands on coating performance, but also cause low-melting-point impurities such as sand and dust to melt, forming molten silicate deposits that adhere to the coating surface, causing coating degradation and seriously impacting the service life of the thermal barrier coating. Therefore, research on thermal barrier coating modification to reduce the adhesion of molten silicate deposits has received widespread attention. Surface finishing is a unique surface treatment method for thermal barrier coatings, widely used in surface modification of various coatings. It not only reduces the surface roughness of the ceramic layer and reduces deposit adhesion, but also improves the surface structure of the thermal barrier coating, enhancing thermal insulation properties and resistance to thermal shock, ultimately increasing the service life of the thermal barrier coating. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for reducing the surface roughness of a thermal barrier coating ceramic layer in response to the above-mentioned deficiencies in the prior art. The purpose is to reduce the surface roughness of the thermal barrier coating ceramic layer so as to cause microstructural changes on the surface of the thermal barrier coating ceramic layer, thereby improving the wettability of the surface of the thermal barrier coating ceramic layer.

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

[0005] A method for reducing the surface roughness of a thermal barrier coating ceramic layer is provided, wherein the surface treatment process is as follows:

[0006] Add abrasive to the drag finishing machine's working chamber, mount the coated workpiece on the fixture, set the machine's main frequency to 30 ± 15 Hz, the total surface finishing time to 30 ± 15 minutes, the forward rotation time to 60 ± 30 seconds, and the reverse rotation time to 60 ± 30 seconds. Start the machine and begin surface finishing.

[0007] The coating system is a thermal barrier coating ceramic layer.

[0008] The abrasive is polymer-coated silicon carbide with a diameter of 100-200 μm. Abrasives with a particle size in this range are more likely to ensure uniform surface roughness of the coating and are easy to prepare, achieving a good balance between cost and effect.

[0009] The surface treatment process parameters are: the main frequency of the drag-type polishing machine is 30±15Hz, the total surface polishing time is 30±15min, the forward rotation time is 60±30s, and the reverse rotation time is 60±30s.

[0010] The method further comprises the steps of cleaning and drying the coating after surface treatment.

[0011] The cleaning steps are as follows: the surface-treated thermal barrier coating ceramic layer is soaked in a 10±5% water-based detergent for 20±5 minutes, then rinsed in running water for at least 3 minutes, and then rinsed in deionized water, one organic solvent, and then a second organic solvent, with each rinse lasting at least 3 minutes.

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

[0013] The drying steps are as follows: after rinsing, take out and put into an oven, and dry at a temperature of 80±10° C. for 10±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] In the surface treatment process of the present invention, polymer-coated silicon carbide abrasives are used. By controlling the total working time, frequency, forward rotation time, and reverse rotation time in a room temperature environment, the surface roughness of the thermal barrier coating ceramic layer is uniformly reduced, while the structural integrity of the thermal barrier coating ceramic layer is maintained, the wettability of the surface of the thermal barrier coating ceramic layer is improved, and ultimately the performance of the thermal barrier coating is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the technical solutions implemented in the present invention, the following briefly explains the drawings required for use in the examples of the present invention. It is obvious that the drawings described below are only some embodiments of the present invention, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0018] Figure 1 The appearance changes of the thermal barrier coating ceramic layer before and after the heat treatment of Example 1; (a) is before heat treatment, (b) is after heat treatment, Figure 1 It can be seen that after surface treatment, the surface of the ceramic layer is obviously smooth, the structure is complete, and there are no excess attachments, indicating that the surface treated ceramic layer remains intact.

[0019] Figure 2 The surface roughness of thermal barrier coatings of Examples 1, 2, 3 and Comparative Example varies; Figure 2It can be seen that due to the difference in the design of the working time parameters, the surface roughness of the coating in the comparative example is 3.12Ra, while the surface roughness of the coating in Examples 1, 2, and 3 is below 1.8Ra. The comparative example changes the working time parameters compared with other embodiments, so the surface roughness is still maintained at a high level.

[0020] Figure 3 The thermal shock life of thermal barrier coatings of Examples 1, 2, 3 and Comparative Example is changed; Figure 3 It can be seen that the method of reducing the surface roughness of the thermal barrier coating ceramic layer increases the thermal shock life of the thermal barrier coating junction by more than 2500 times. Compared with other embodiments, the comparative example changes the working time parameters, so the surface roughness remains at a high level, resulting in a lower thermal shock life. DETAILED DESCRIPTION

[0021] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying 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 efforts 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 detailed description below, many specific details are provided to facilitate a comprehensive understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can also be implemented without these specific details. The technical solutions of the invention will be further described below in conjunction with the embodiments:

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

[0024] (1) The coating system is a thermal barrier coating ceramic layer. The abrasive is polymer-coated silicon carbide with a diameter of 100-200 μm. The surface treatment process parameters are: the main frequency of the drag-type polishing machine is 30±15 Hz, the total surface finishing time is 30±15 minutes, the forward rotation time is 60±30 seconds, and the reverse rotation time is 60±30 seconds.

[0025] (2) Cleaning: After surface treatment, the thermal barrier coating ceramic layer is soaked in a 10±5% water-based detergent for 20±5 minutes. Rinse in running water for 3 minutes, followed by rinsing in deionized water, one organic solvent, and two organic solvents, each for 3 minutes. The water-based detergent is a degreaser with a pH of 7. Specifically, the water-based detergent can be an environmentally friendly water-based detergent, a multi-purpose water-based detergent, or a strong water-based detergent. The organic solvent is ethanol of analytical grade.

[0026] ⑶. Drying: After rinsing, take out and put into the oven, dry at 85℃ for 10 minutes.

[0027] Example 1:

[0028] Surface Treatment: Mount the prepared thermal barrier coating on a fixture. Add polymer-coated silicon carbide abrasive to a drag polishing machine. Set the machine's main frequency to 30 Hz and the surface finishing time to 20 minutes, with a forward rotation time of 60 seconds and a reverse rotation time of 60 seconds. Remove the thermal barrier coating after the working time is complete.

[0029] Example 2:

[0030] Surface Treatment: Mount the prepared thermal barrier coating on a fixture. Add polymer-coated silicon carbide abrasive to a drag polishing machine. Set the machine's main frequency to 30 Hz and the surface finishing time to 30 minutes, with a forward rotation time of 60 seconds and a reverse rotation time of 60 seconds. Remove the thermal barrier coating after the working time is complete.

[0031] Example 3:

[0032] Surface Treatment: Mount the prepared thermal barrier coating on a fixture. Add polymer-coated silicon carbide abrasive to a drag polishing machine. Set the machine's main frequency to 30 Hz and the surface finishing time to 40 minutes, with a forward rotation time of 60 seconds and a reverse rotation time of 60 seconds. Remove the thermal barrier coating after the working time is complete.

[0033] Comparative Example:

[0034] Surface Treatment: Mount the prepared thermal barrier coating on a fixture. Add polymer-coated silicon carbide abrasive to a drag polishing machine. Set the machine's main frequency to 30 Hz and the total polishing time to 5 minutes, with a forward rotation time of 60 seconds and a reverse rotation time of 60 seconds. Remove the thermal barrier coating after the working time is complete.

[0035] like Figure 2The figure shows the surface roughness changes of thermal barrier coatings in Examples 1, 2, 3 and the comparative example. It can be seen that due to the difference in the design of the working time parameters, the surface roughness of the coating in the comparative example is 3.12Ra, while the combination of the working time parameters and the main frequency parameter design in Examples 1, 2, and 3 makes the surface roughness of the coating below 1.8Ra. In the surface treatment process of the embodiment of the present invention, the surface roughness of the thermal barrier coating is reduced by controlling the working time. On the other hand, Figure 3 It can also be seen that the surface roughness of Examples 1, 2, and 3 is relatively small, and it is found that the thermal shock life of the thermal barrier coating is greatly improved.

[0036] By using polymer-coated silicon carbide abrasives and controlling the working time, main frequency, forward rotation time and reverse rotation time, the surface roughness of the ceramic layer can be reduced to below 1.8Ra. At the same time, the surface structural integrity of the ceramic layer can be maintained, the surface wettability of the thermal barrier coating ceramic layer is improved, and ultimately the performance of the thermal barrier coating is improved.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should all be covered by the scope of protection of the present invention.

Claims

1. A method for reducing the surface roughness of a thermal barrier coating ceramic layer, characterized in that: The surface treatment method process is as follows: Add abrasives to the working cabin of the drag-type polishing machine, hang the coated workpiece on the tooling, set the main frequency of the drag-type polishing machine to 30±15Hz, the total surface polishing time to 30±15Hz, the total surface polishing time to 30±15min, the forward time to 60±30s, and the reverse time to 60±30s; start the equipment and perform surface polishing.

2. The method according to claim 1, characterized in that: The coating system is a thermal barrier coating ceramic layer.

3. The method according to claim 1, characterized in that: The abrasive is polymer-coated silicon carbide with a diameter of 100-200 μm.

4. The method according to claim 1, characterized in that: The surface treatment process parameters are: the main frequency of the drag-type polishing machine is 30±15Hz, the total surface polishing time is 30±15min, the forward rotation time is 60±30s, and the reverse rotation time is 60±30s.

5. The method according to claim 1, characterized in that: The surface treatment method further comprises the steps of cleaning and drying the coating after the surface treatment.

6. The method according to claim 5, characterized in that: The cleaning steps are as follows: soak the surface-treated thermal barrier coating ceramic layer in a 10±5% water-based cleaning agent for 20±5 minutes, then rinse in running water for no less than 3 minutes, and then rinse in deionized water, one organic solvent, and two organic solvents in sequence, and each rinse must not be less than 3 minutes.

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

5.

8. The method according to claim 5, characterized in that: The drying steps are as follows: after rinsing, take out and put into an oven, and dry at 80±10°C for 10±5min.

9. The method according to claim 8, characterized in that: The first and second organic solvents are acetone or ethanol, and the purity is analytical grade.

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