Method for sealing and electrodepositing Co-Cr2C3 plating layer behind GH5605 transition section
A Co-Cr2C3 coating was prepared at the rear seal of the transition section of the combustion chamber of a heavy-duty gas turbine by means of suspension electrodeposition, which solved the shortcomings of spraying and electroplating methods, achieved effective protection of complex structures, and improved the wear resistance and high temperature stability of the sealing structure.
Patent Information
- Application Number
- CN202511896313.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-02-10
AI Technical Summary
Existing technologies make it difficult to prepare Co-Cr2C3 coatings at the post-seal area of the transition section of the combustion chamber in heavy-duty gas turbines. Spraying technology cannot penetrate complex structures, and electroplating methods are not applicable, resulting in unresolved wear problems.
A Co-Cr2C3 coating is prepared on a substrate using a suspension electrodeposition method with specific electroplating solution formulations and process parameters. This includes substrate pretreatment, protection of non-coating areas, electroplating solution preparation, and electroplating process to ensure coating uniformity and adhesion.
The uniform coating of Co-Cr2C3 on complex surfaces solves the wear problem, improves the service life and reliability of the sealing structure, and has excellent coating performance, with good wear resistance and high temperature stability.
Smart Images
Figure CN121496519A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of surface treatment technology, and specifically to a method for electrodepositing a Co-Cr2C3 coating for the post-seal of the transition section of the combustion chamber of a heavy-duty gas turbine GH5605. Background Technology
[0002] The transition section of the combustion chamber in a heavy-duty gas turbine is a crucial component guiding the transfer of gas flow. Its core function is to transition the circular cross-section of the combustion chamber flame tube outlet to the fan-shaped cross-section of the turbine guide vanes. By changing the cross-sectional shape, the cross-sectional area of the airflow passage converges to meet the requirements of the turbine inlet. Due to the significant pressure difference between the inside and outside of the transition section, a sealing structure must be installed at the point where the transition section outlet connects to the turbine to ensure the normal operation of the gas turbine.
[0003] In existing technologies, the preparation of the Co-Cr2C3 coating for the post-seal of the GH5605 transition section mainly employs spraying technology. However, this technology has significant drawbacks: the post-seal structure of the transition section is unique and complex, making it difficult for the spray gun to penetrate the complex structure, thus hindering coating preparation and failing to effectively guarantee the protective performance of the sealing area. Furthermore, there is limited research in China on methods for electrodepositing Co-Cr2C3 coatings, and existing electroplating methods, due to issues with process parameters and coating adhesion, are not suitable for the specific requirements of the GH5605 transition section post-seal and cannot solve its wear problem.
[0004] Co-Cr2C3 composite coatings possess excellent performance advantages, exhibiting good interfacial compatibility with most materials. Furthermore, in operating environments above 300℃, a glassy glaze layer forms on the coating surface as the temperature rises, providing excellent friction reduction. It also maintains a certain level of hardness, especially at 700℃, making it an ideal protective coating for the transition section post-seal. Therefore, developing a Co-Cr2C3 coating electrodeposition method suitable for the structural characteristics of the GH5605 transition section post-seal is crucial for solving the transition section wear problem and improving the operational reliability of heavy-duty gas turbines. Summary of the Invention
[0005] This invention provides a method for electrodepositing a Co-Cr2C3 coating at the outlet and turbine connection point of the transition section of a heavy-duty gas turbine combustion chamber to solve the wear problem caused by the pressure difference between the inside and outside of the transition section.
[0006] The present invention discloses a method for electrodepositing a Co-Cr2C3 coating on the post-transition seal of GH5605, which is carried out according to the following steps:
[0007] 1. Substrate pretreatment: The substrate is subjected to shot peening, ultrasonic cleaning with ethanol, rinsing with distilled water, alkaline degreasing, hot distilled water washing, room temperature distilled water rinsing, oxide film removal, room temperature distilled water rinsing, bleaching, room temperature distilled water rinsing, activation, and room temperature distilled water rinsing in sequence.
[0008] 2. Protection of non-plated areas: Use insulating tape to cover the non-plated areas on the substrate;
[0009] III. Preparation of electroplating solution: Prepare the electroplating solution according to the following components and concentrations: CoSO4·7H2O 400g / L, NaCl 20g / L and H3BO3 30g / L, with additives of sodium dodecyl sulfate 0.1g / L, saccharin 0.5g / L, thiol 0.05g / L, and water as the solvent.
[0010] IV. Electroplating process: First, the substrate is pre-plated with nickel, and then the substrate is electroplated by adding Cr2C3 powder to the electroplating solution using the suspension electrodeposition method to obtain the electroplated substrate.
[0011] V. Post-processing: The electroplated substrate is cleaned and dried to obtain the GH5605 transition section rear seal with Co-Cr2C3 coating.
[0012] The beneficial effects of this invention are:
[0013] This invention employs electrodeposition technology, especially suspension electrodeposition, which effectively solves the problem of complex sealing structures after the transition section and the inability of spraying technology to penetrate them. It can uniformly coat complex surfaces with Co-Cr2C3 coating, specifically addressing the wear problem caused by pressure difference at the connection between the combustion chamber transition section outlet and the turbine in heavy-duty gas turbines, and significantly improving the service life and reliability of the transition section sealing structure.
[0014] This invention optimizes the electroplating solution formulation and electrodeposition process parameters, expanding the preparation method of Co-Cr2C3 coatings. The prepared coating exhibits excellent performance: the thickness is adjustable within the range of 0.08-0.15 mm to meet the protection requirements under different working conditions; the Vickers hardness reaches 410-500 HV300, providing good wear resistance; the porosity is close to 0%, effectively preventing the intrusion of corrosive media and improving the protective effect; the coating adhesion is >61.23 MPa, ensuring a firm bond with the substrate and preventing peeling; the chromium carbide mass fraction is 30%-40%, guaranteeing the coating's high-temperature wear resistance and maintaining stable performance even at 700℃.
[0015] The process steps of this invention are clear and easy to operate. The required equipment is conventional, which facilitates industrial promotion and application. It provides a new and effective way for the surface protection of GH5605 material and similar complex structural parts, and has important engineering application value. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the sealing structure after the transition section of the electrodeposited Co-Cr2C3 (marked 1 is the Co-Cr2C3 coating area).
[0017] Figure 2 This is a photograph of the seal after the transition section of the electrodeposited Co-Cr2C3.
[0018] Figure 3 SEM image of the Co-Cr2C3 coating;
[0019] Figure 4 EDS image of Co-Cr2C3 coating. Detailed Implementation
[0020] Specific Implementation Method 1: A method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 according to this implementation method is carried out according to the following steps:
[0021] 1. Substrate pretreatment: The substrate is subjected to shot peening, ultrasonic cleaning with ethanol, rinsing with distilled water, alkaline degreasing, hot distilled water washing, room temperature distilled water rinsing, oxide film removal, room temperature distilled water rinsing, bleaching, room temperature distilled water rinsing, activation, and room temperature distilled water rinsing in sequence.
[0022] 2. Protection of non-plated areas: Use insulating tape to cover the non-plated areas on the substrate;
[0023] III. Preparation of electroplating solution: Prepare the electroplating solution according to the following components and concentrations: CoSO4·7H2O 400g / L, NaCl 20g / L and H3BO3 30g / L, with additives of sodium dodecyl sulfate 0.1g / L, saccharin 0.5g / L, thiol 0.05g / L, and water as the solvent.
[0024] IV. Electroplating process: First, the substrate is pre-plated with nickel, and then the substrate is electroplated by adding Cr2C3 powder to the electroplating solution using the suspension electrodeposition method to obtain the electroplated substrate.
[0025] V. Post-processing: The electroplated substrate is cleaned and dried to obtain the GH5605 transition section rear seal with Co-Cr2C3 coating.
[0026] In the pretreatment process of this embodiment, conventional chemical reagents and processes in the art can be used for oxide film removal, bleaching, and activation to ensure that there is no oxide layer or impurity residue on the substrate surface, thus providing a guarantee for the subsequent coating bonding.
[0027] In this embodiment, insulating tape is used to cover the areas on the substrate that do not require plating, preventing these areas from being plated during the electroplating process and ensuring the structural accuracy of the product.
[0028] In this embodiment, CoSO4·7H2O provides cobalt ions for the plating layer, NaCl is used to improve the conductivity of the plating solution, H3BO3 plays a role in stabilizing the pH value of the plating solution, sodium dodecyl sulfate can prevent pinholes in the plating layer, saccharin can refine the grains of the plating layer, and thiol helps to improve the gloss and adhesion of the plating layer.
[0029] In this embodiment, the pre-plating of nickel adopts a conventional process in the art, which enhances the bonding strength between the subsequent plating layer and the substrate through the pre-plating of nickel layer.
[0030] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the shot peening treatment in step one uses 5μm alumina shot. Other steps and parameters are the same as in Specific Implementation Method One.
[0031] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 in that the ultrasonic cleaning time with ethanol in step one is 2 hours. Other steps and parameters are the same as in Specific Implementation Method 1.
[0032] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method One in that the alkaline degreasing conditions described in step one are 80-90℃ and the time is 2 hours. Other steps and parameters are the same as in Specific Implementation Method One.
[0033] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method One in that the hot distilled water washing temperature in step one is 80℃. Other steps and parameters are the same as in Specific Implementation Method One.
[0034] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method One in that the pre-plating nickel treatment adopts a conventional pre-plating nickel process in the art to ensure the bonding performance between the substrate surface and the subsequent plating layer. Other steps and parameters are the same as in Specific Implementation Method One.
[0035] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method One in that the amount of Cr2C3 powder added in step four is 500 g / L, and the median particle size is 5 μm. Other steps and parameters are the same as in Specific Implementation Method One.
[0036] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method One in that the electrodeposition temperature in step four of the suspension electrodeposition method is controlled at 40℃, the magnetic stirring rate is 200 r / min, and the electrodeposition time is 1 h. Other steps and parameters are the same as in Specific Implementation Method One.
[0037] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method One in that the Co-Cr2C3 coating thickness is 0.08-0.15 mm, the Vickers hardness is 410-500 HV300, the porosity is close to 0%, and the coating adhesion is >61.23 MPa. Other steps and parameters are the same as in Specific Implementation Method One.
[0038] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Nine in that the chromium carbide mass fraction in the Co-Cr2C3 coating is 30%-40%. Other steps and parameters are the same as in Specific Implementation Method Nine.
[0039] The beneficial effects of the present invention are verified using the following embodiments:
[0040] Example 1: A method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 is carried out according to the following steps:
[0041] Substrate pretreatment: GH5605 transition section post-sealing substrate was selected. First, the substrate surface was shot-peened with 5μm alumina pellets to enhance surface activity. Then, the substrate was ultrasonically cleaned in ethanol for 2 hours to remove surface oil and dust. After removal, it was rinsed three times with distilled water. The rinsed substrate was then immersed in an alkaline degreasing solution at 85℃ for 2 hours. The alkaline degreasing solution used a conventional formula in this field. Afterward, it was cleaned twice with hot distilled water at 80℃, and then rinsed three times with distilled water at room temperature. The oxide film was removed using a dilute hydrochloric acid solution for 15 minutes, followed by rinsing twice with distilled water. Bleaching was performed using a hydrogen peroxide solution for 5 minutes, followed by rinsing twice with distilled water. Activation was performed using a dilute sulfuric acid solution for 10 minutes. Finally, it was rinsed three times with distilled water to complete the pretreatment.
[0042] Protection of non-plated areas: Based on the structural design of the transition section and the subsequent seal, use high-temperature resistant insulating tape to completely cover the areas that do not require Co-Cr2C3 plating, ensuring that the tape is firmly adhered and without any omissions.
[0043] Electroplating solution preparation: Accurately weigh 400g of CoSO4·7H2O, 20g of NaCl and 30g of H3BO3, add an appropriate amount of distilled water and stir until completely dissolved; then add 0.1g of sodium dodecyl sulfate, 0.5g of saccharin and 0.05g of thiol, continue stirring until uniform, and add distilled water to 1L to obtain the required electroplating solution.
[0044] Electroplating process: The pretreated and protected substrate is used as the cathode, and the nickel plate is used as the anode. The substrate is immersed in the electroplating solution for pre-nickel plating. The pre-nickel plating process parameters are: current density 2A / dm³. 2The temperature was 35℃, and the time was 10 min. After the pre-plating was completed, Cr3C2 powder (median particle size 5μm) was added to the electroplating solution at a rate of 500 g / L. The magnetic stirrer was turned on, and the stirring speed was adjusted to 200 r / min. After the Cr3C2 powder was uniformly suspended, the electrodeposition temperature was adjusted to 40℃, and the current density was controlled at 3 A / dm³. 2 Electrodeposition was performed for 1 hour.
[0045] Post-processing: After electrodeposition, turn off the power, remove the substrate, rinse the surface with distilled water to remove residual electroplating solution, wipe the surface with anhydrous ethanol, and finally dry it with a hot air gun to obtain the GH5605 transition section rear seal with Co-Cr3C2 coating.
[0046] The Co-Cr3C2 coating prepared in this embodiment was subjected to performance testing, and the results are as follows: the coating thickness is 0.12 mm, the Vickers hardness is 460 HV300, the porosity is <0.1% (close to 0%), the coating adhesion is 68.5 MPa, and the chromium carbide mass fraction is 35%. All performance indicators meet the design requirements, and the coating surface is uniform, smooth, and tightly bonded to the substrate.
Claims
1. A method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of a GH5605 material, characterized in that... The method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 is performed according to the following steps:
1. Substrate pretreatment: The substrate is subjected to shot peening, ultrasonic cleaning with ethanol, rinsing with distilled water, alkaline degreasing, hot distilled water washing, room temperature distilled water rinsing, oxide film removal, room temperature distilled water rinsing, bleaching, room temperature distilled water rinsing, activation, and room temperature distilled water rinsing in sequence.
2. Protection of non-plated areas: Use insulating tape to cover the non-plated areas on the substrate; III. Preparation of electroplating solution: Prepare the electroplating solution according to the following components and concentrations: CoSO4·7H2O 400 g / L, NaCl 20 g / L and H3BO3 30 g / L, with additives of sodium dodecyl sulfate 0.1 g / L, saccharin 0.5 g / L, thiol 0.05 g / L, and water as the solvent. IV. Electroplating process: First, the substrate is pre-plated with nickel, and then the substrate is electroplated by adding Cr2C3 powder to the electroplating solution using the suspension electrodeposition method to obtain the electroplated substrate. V. Post-processing: The electroplated substrate is cleaned and dried to obtain the GH5605 transition section rear seal with Co-Cr2C3 coating.
2. The method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 according to claim 1, characterized in that... The shot peening process described in step one uses 5μm alumina pellets.
3. The method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 according to claim 1, characterized in that... The ultrasonic cleaning time with ethanol in step one is 2 hours.
4. The method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 according to claim 1, characterized in that... The alkaline degreasing conditions described in step one are 80-90℃ and 2 hours.
5. The method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 according to claim 1, characterized in that... The temperature of the hot distilled water washing in step one is 80℃.
6. The method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 according to claim 1, characterized in that... The pre-plating nickel treatment employs conventional pre-plating nickel processes in the art to ensure the adhesion performance between the substrate surface and subsequent plating layers.
7. The method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 according to claim 1, characterized in that... The amount of Cr2C3 powder added in step four is 500 g / L, and the median particle size is 5 μm.
8. The method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 according to claim 1, characterized in that... In step four, the electrodeposition temperature is controlled at 40°C, the magnetic stirring rate is 200 r / min, and the electrodeposition time is 1 h.
9. The method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 according to claim 1, characterized in that... The Co-Cr2C3 coating has a thickness of 0.08-0.15 mm, a Vickers hardness of 410-500 HV300, a porosity close to 0%, and a coating adhesion strength >61.23 MPa.
10. The method for electrodepositing a Co-Cr2C3 coating after sealing the transition section of GH5605 according to claim 9, characterized in that... The mass fraction of chromium carbide in the Co-Cr2C3 coating is 30%-40%.