A special-shaped anode design method and device for single-turbine guide vane plating platinum based on electrochemical simulation and a plating method

Abstract

This invention discloses a design method, apparatus, and electroplating method for a special irregular-shaped anode for platinum plating on a single turbine guide vane based on electrochemical simulation. It belongs to the field of precision electroplating technology for hot-end components of aero-engines. The method first obtains a complete three-dimensional geometric model of the single turbine guide vane, preserving its external production characteristics, and constructs a geometric model of the electroplating system including a cathode, a special irregular-shaped anode, and an electrolyte domain. A secondary current distribution model is used to build an electrochemical simulation environment for platinum sulfamate plating, setting the kinetic parameters for the cathode platinum deposition reaction and the anode oxygen evolution reaction. Initial simulation is conducted using a conventional flat anode as a benchmark to quantitatively identify the core areas of uneven coating on the blade surface. The system introduces five special irregular-shaped anode structures, optimizing the anode profile, equidistant distance, and spatial position through parametric scanning. The optimal anode design scheme is determined through iterative optimization using the coating thickness variance as the objective function. This invention can significantly shorten the process development cycle and reduce costs.

Description

Technical Field

[0001] This invention belongs to the field of precision electroplating technology for hot-end components of aero-engines, specifically relating to a design method, device, and electroplating method for a special irregular anode for platinum plating of single turbine guide vanes based on electrochemical simulation. Background Technology

[0002] The single-turbine guide vane of an aero-engine is a core hot-end component that withstands the impact of high-temperature combustion gases. Its service environment temperature can reach over 1100℃, and it also endures the scouring and corrosion of high-pressure, high-speed airflow. To significantly improve the blade's resistance to high-temperature oxidation and hot corrosion, the industry commonly employs a composite protection system of "platinum coating + aluminizing layer." The uniform and dense platinum coating is crucial for ensuring the quality of the subsequent aluminizing layer and the long-term service life of the blade. The uniformity of the platinum coating thickness directly determines the overall performance of the protective layer: excessively thin coatings in certain areas lead to premature oxidation and failure, while excessively thick coatings in certain areas generate significant internal stress during thermal cycling, causing fatal defects such as coating cracking and peeling.

[0003] Single turbine guide vanes possess extremely complex three-dimensional geometry, including highly curved blade base and back surfaces, sharp leading and trailing edges, and rounded transitions between the blade edge and the blade body. During electroplating, current lines generate a strong concentration effect at edges and corners where curvature abruptly changes, resulting in localized current densities in these areas that are much higher than in planar areas. This leads to an uneven phenomenon of "excessively thick at the tip and too thin on the surface." Particularly in the transition area between the blade edge and the blade body, due to the abrupt change in geometry, current concentration easily causes quality problems such as peeling and blistering of the plating, severely impacting the yield of the blades.

[0004] Currently, the industry commonly uses conventional flat anodes or simple cylindrical anodes for platinum plating of single turbine guide vanes. Conventional flat anodes are simple in structure and easy to process, but the electric field they generate is a parallel and uniform electric field, which is completely unsuitable for the complex curved surface of the blade, resulting in extremely uneven coating distribution across the entire surface. Although simple cylindrical anodes can improve the current distribution in the flow channel to some extent, they still cannot precisely control the large curvature surfaces of the blade base and blade back. The variance of the coating thickness across the entire surface is usually greater than 3.0, which is far from meeting the ±10% coating thickness tolerance requirement of the new generation of aero engines.

[0005] In existing electroplating processes, anode design primarily relies on the experience of process engineers through repeated trial and error adjustments, lacking a scientific and quantitative design method. While there are reports of using finite element analysis software for anode design assistance in electroplating, or designing the shape of shaped anodes used in electrodeposition through electric field analysis and optimization, existing methods still struggle to achieve globally optimal anode designs for complex parts like single turbine guide vanes, resulting in poor process stability and batch consistency. Currently, there is no dedicated non-standard anode system technology solution for optimizing the full surface uniformity of single turbine guide vanes. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned technical problems and provide a design method, apparatus and electroplating method for a special irregular anode for platinum plating of single turbine guide vanes based on electrochemical simulation.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for designing a special irregular anode for platinum plating on a single turbine guide vane based on electrochemical simulation, the method comprising the following steps:

[0009] S1: Obtain a three-dimensional geometric model of a single turbine guide vane, fully preserving all external structural features of the blade surface, upper and lower edge plates, and mounting edges; construct a geometric model of an electroplating system including a cathode, anode, and electrolyte domain, wherein the cathode is the single turbine guide vane to be electroplated;

[0010] S2: Establish an electrochemical simulation environment, adopt a secondary current distribution model, and set electrochemical simulation parameters, including electrolyte conductivity, equilibrium potential and exchange current density of the cathode platinum deposition reaction, and equilibrium potential and exchange current density of the anode oxygen evolution reaction.

[0011] S3: Using a conventional flat anode as the initial anode, run an electroplating process simulation to obtain the current density distribution and coating thickness distribution on the surface of a single turbine guide vane, and quantitatively identify the core areas with uneven coating thickness.

[0012] S4: Introduce a special irregular anode model to replace the conventional flat anode in the geometric model. The special irregular anode adopts a conformal shell structure that is adapted to the outer contour of the single turbine guide vane. Its inner contour maintains a preset distance from the outer surface of the blade. Adjust the profile parameters and spatial position parameters of the special irregular anode, and rerun the simulation to obtain the optimized coating distribution data.

[0013] S5: Using the coating thickness variance as the objective function, determine the design scheme of the special irregular anode through parameter iteration optimization, and output its geometric parameters, profile and spatial coordinates.

[0014] Further, in step S2, the equilibrium potential of the cathode platinum deposition reaction is 1.05–1.25 V, the exchange current density is 0.5–2 A / m², and the transfer coefficient is 0.3–0.7; the equilibrium potential of the anodic oxygen evolution reaction is 1.15–1.30 V, and the exchange current density is 0.5 × 10⁻⁶. -4 ~2×10 -4 A / m², with a transfer coefficient of 0.3 to 0.7.

[0015] Further, in step S2, the electrolyte is a water-soluble platinum salt solution with a conductivity range of 10~20 S / m and a temperature of 25~35℃; the water-soluble platinum salt plating solution is selected from at least one of aminosulfonic acid platinum plating solution, dinitrosodiamine platinum plating solution, chloroplatinic acid plating solution, platinum sulfate plating solution, and hydroxyethylenediamine platinum plating solution.

[0016] Furthermore, in steps S3 and S4, the coating thickness δ is calculated according to Faraday's law using the following formula:

[0017]

[0018] in, The local current density on the cathode surface. The molar mass of platinum, The number of electrons in the platinum deposition reaction and =2, It is Faraday's constant. The density of platinum, This refers to the electroplating time.

[0019] Furthermore, in step S4, the structure type of the special irregular anode is one of the following: full-surface conformal wrapping type, open-hole conformal type, front and rear edge shielded conformal type, front and rear edge extended semi-wrapped type, and split-type leaf basin with double-sided conformal type.

[0020] Furthermore, when the structure of the special irregular anode is a conformal wrapping type covering the entire blade surface, the structure is an integral closed shell, and its inner contour maintains a preset distance from the blade base, blade back, leading edge and trailing edge of the entire blade surface, and the surface has no openings.

[0021] When the structure of the special irregular anode is a blade back opening conformal type, the structure is based on the conformal covering structure of the entire blade surface, and multiple sets of elliptical convection holes are opened in the non-critical area of ​​the blade back, which are evenly distributed along the axial and circumferential directions.

[0022] When the structure type of the special irregular anode is a front and rear edge shielded blade conformal type, the structure adopts an integrated conformal shell structure formed by hollowing out the blade blade profile proportionally. The inner contour maintains a preset distance from the entire blade blade profile. The front and rear edge areas of the shell are insulated and shielded to form non-conductive areas, and only the blade basin side and blade back side areas are conductive working surfaces.

[0023] When the structure of the special irregular anode is a semi-enclosed leaf back type with front and rear edge extension, the main body of the structure is a leaf back side conformal conductive plate, whose front and rear edge boundaries extend along the circumference of the leaf towards the leaf basin side, covering the leaf basin side edge area of ​​the front and rear edges, and the middle of the leaf basin is completely open.

[0024] When the structure of the special irregular anode is a split-type leaf basin and leaf back double-sided conformal type, the structure includes a leaf basin side conformal anode plate and a leaf back side conformal anode plate. The leaf basin side conformal anode plate and the leaf back side conformal anode plate maintain a preset distance from the leaf basin surface and the leaf back surface of the blade, respectively, and there is no connecting structure between the front and rear edges.

[0025] Furthermore, the preset distance of the special irregular anode is 10mm to 30mm.

[0026] Furthermore, in steps S1 and S4, a free tetrahedral mesh is used to discretize the entire computational domain, with the cathode blade surface and the anode surface having their meshes refined.

[0027] A special-shaped anode device for platinum plating of a single turbine guide vane includes a special-shaped anode body, which is manufactured after the design parameters are determined by the above-mentioned method. The special-shaped anode body is the only working anode of the electroplating system. Its structure is a conformal shell adapted to the outer contour of the single turbine guide vane. The distance between its inner contour and the outer surface of the blade body is 10mm to 30mm. It only covers the working area of ​​the blade body, and the upper and lower edge plates and mounting edges of the blade are completely exposed. The special-shaped anode body is configured to be connected to the positive terminal of a DC power supply.

[0028] A method for plating a single turbine guide vane with platinum includes the following steps: arranging a special shaped anode body according to the above-mentioned apparatus; connecting the special shaped anode body to the positive terminal of a DC power supply, and connecting the single turbine guide vane to be plated to the negative terminal of a DC power supply; performing constant current electroplating on the single turbine guide vane in an electrolyte to obtain a platinum coating with uniform thickness across the entire surface.

[0029] The beneficial effects of this invention are as follows:

[0030] This invention designs a special-shaped anode for the complete external structure of a single turbine guide vane (including the rim plate, mounting edge, and transition zone). It precisely solves the unique technical problems of single blades, such as current concentration in the rim plate and blade transition zone and uneven electric field distribution on the blade base and blade back. The simulation covers all outer surfaces of the blade and is highly matched with actual production conditions, providing a direct quantitative design basis for the platinum plating process of single blades.

[0031] This invention constructs a full-spectrum special-shaped anode technology system containing five structures. The coating thickness variance is reduced from 4.0677 of conventional flat anodes to a minimum of 1.7342, with a uniformity improvement rate of 57.4%. The maximum coating thickness is reduced from 224μm to 13.9μm, a reduction of 93.8%, which completely solves the problems of tip effect at the leading and trailing edges and current shielding in the middle of the blade basin.

[0032] The five non-standard anode designs of this invention cover the needs of different application scenarios: the leading and trailing edge shielding design balances uniformity and engineering practicality, making it the preferred choice for mass industrial production; the full-surface conformal wrapping design provides a theoretical uniformity benchmark and is suitable for high-precision core blades; the blade back opening design reduces anode material usage while ensuring uniformity, facilitating processing and installation, and is suitable for various electroplating processes; the leading and trailing edge extension design is simple in structure and low in cost, suitable for pre-plating processes and low-end blades; and the split design provides a structural foundation and simulation platform for future independent current control technology, possessing significant technological reserve value.

[0033] This invention uses electrochemical simulation technology for quantitative design, eliminating the need for physical trial and error. It can shorten the process development cycle from the traditional 3-6 months to 1-2 weeks, reduce development costs by more than 70%, and all schemes strictly comply with Faraday's law of electrolysis, with data exhibiting rigorous physical consistency and repeatability. Attached Figure Description

[0034] Appendix Figure 1 This is a schematic diagram of a three-dimensional geometric model of a conventional flat anode single turbine guide vane electroplating system;

[0035] Appendix Figure 2 This is a schematic diagram of a three-dimensional geometric model of the electroplating system for a single turbine guide blade with a conformal anode covering the entire blade profile, as described in this invention.

[0036] Appendix Figure 3 This is a schematic diagram of a three-dimensional geometric model of the single turbine guide blade electroplating system with a fully conformal anode with an open back of the blade according to the present invention.

[0037] Appendix Figure 4 This is a schematic diagram of a three-dimensional geometric model of the electroplating system for a single turbine guide blade with a leading and trailing edge shielded conformal anode, as described in this invention.

[0038] Appendix Figure 5This is a schematic diagram of a three-dimensional geometric model of the electroplating system for a single turbine guide vane with a semi-enclosed anode on the leading and trailing edges of the blade, as described in this invention.

[0039] Appendix Figure 6 This is a schematic diagram of a three-dimensional geometric model of the electroplating system for a single turbine guide blade with a split blade basin and double-sided conformal anodes on the blade back, as described in this invention.

[0040] Appendix Figure 7 This is a schematic diagram of the potential distribution and current density streamlines in the electrolyte domain under conventional anodic conditions;

[0041] Appendix Figure 8 This is a cloud map showing the thickness distribution of the cathode surface coating under conventional anodic conditions;

[0042] Appendix Figure 9 This is a schematic diagram of the potential distribution and current density streamlines of the electrolyte domain under the condition of conformal anode coverage of the entire blade surface of the present invention;

[0043] Appendix Figure 10 This is a cloud map showing the thickness distribution of the cathode surface coating under the condition of conformal anode coverage of the entire blade profile according to the present invention;

[0044] Appendix Figure 11 This is a schematic diagram of the potential distribution and current density streamlines of the electrolyte domain under the condition of the leaf-back open-hole fully conformal anode of the present invention;

[0045] Appendix Figure 12 This is a cloud map showing the thickness distribution of the cathode surface coating under the leaf-back opening type fully conformal anode condition of the present invention;

[0046] Appendix Figure 13 This is a schematic diagram of the potential distribution and current density streamlines of the electrolyte domain under the condition of the leading and trailing edge shielded blade conformal anode of the present invention;

[0047] Appendix Figure 14 This is a cloud map showing the thickness distribution of the cathode surface coating under the conformal anode condition of the leading and trailing edge shielded blade of the present invention;

[0048] Appendix Figure 15 This is a schematic diagram of the potential distribution and current density streamlines of the electrolyte domain under the condition of semi-enclosed anode with extended leading and trailing edges of the blade back of the present invention.

[0049] Appendix Figure 16 This is a cloud map showing the thickness distribution of the cathode surface coating under the condition of semi-enclosed anode with extended leading and trailing edges of the blade back according to the present invention;

[0050] Appendix Figure 17 This is a schematic diagram of the potential distribution and current density streamlines of the electrolyte domain under the condition of the double-sided conformal anode on the leaf back of the split-type leaf basin of the present invention;

[0051] Appendix Figure 18 This is a cloud map showing the thickness distribution of the cathode surface coating under the condition of the double-sided conformal anode on the back of the split blade basin of the present invention;

[0052] Appendix Figure 19 This is a bar chart comparing the maximum / minimum coating thicknesses for different anode schemes of the present invention;

[0053] Appendix Figure 20 This is a bar chart comparing the variance of platinum coating thickness under different anode schemes in this invention. Detailed Implementation

[0054] The present invention will now be further described with reference to the accompanying drawings.

[0055] This invention provides a method for designing a special-shaped anode for platinum plating on single turbine guide vanes based on electrochemical simulation. The method includes the following steps:

[0056] S1: Obtain a three-dimensional geometric model of a single turbine guide vane, fully preserving all external structural features of the blade surface, upper and lower edge plates, and mounting edges; construct a geometric model of an electroplating system including a cathode, anode, and electrolyte domain, wherein the cathode is the single turbine guide vane to be electroplated;

[0057] S2: Establish an electrochemical simulation environment, adopt a secondary current distribution model, and set electrochemical simulation parameters, including electrolyte conductivity, equilibrium potential and exchange current density of the cathode platinum deposition reaction, and equilibrium potential and exchange current density of the anode oxygen evolution reaction.

[0058] The equilibrium potential for the cathode platinum deposition reaction is 1.05–1.25 V, and the exchange current density is 0.5–2 A / m. 2 The transfer coefficient is 0.4–0.6; the equilibrium potential of the anodic oxygen evolution reaction is 1.15–1.30 V, and the exchange current density is 0.5 × 10⁻⁶. -4 ~2×10 -4 A / m 2 The transmission coefficient is 0.4 to 0.6.

[0059] Preferably, the electrolyte is a platinum sulfamate plating solution with a conductivity of 10~20 S / m and an operating temperature of 30℃; the cathode reaction is a platinum deposition reaction with an equilibrium potential of 1.19V and an exchange current density of 1 A / m. 2 The transfer coefficient is 0.5; the anodic reaction is the oxygen evolution reaction, the equilibrium potential is 1.23V, and the exchange current density is 1×10⁻⁶. -4 A / m 2 The transfer coefficient is 0.5.

[0060] S3: Using a conventional flat anode as the initial anode, run an electroplating process simulation to obtain the current density distribution and coating thickness distribution on the surface of a single turbine guide vane, and quantitatively identify the core areas with uneven coating thickness.

[0061] S4: Introduce a special irregular anode model to replace the conventional flat anode in the geometric model. The special irregular anode adopts a conformal shell structure that is adapted to the outer contour of the single turbine guide vane. Its inner contour maintains a preset distance from the outer surface of the blade. Adjust the profile parameters and spatial position parameters of the special irregular anode, and rerun the simulation to obtain the optimized coating distribution data.

[0062] S5: Using the coating thickness variance as the objective function, determine the design scheme of the special irregular anode through parameter iteration optimization, and output its geometric parameters, profile and spatial coordinates.

[0063] In this embodiment, in steps S3 and S4, the coating thickness δ is calculated according to Faraday's law using the following formula:

[0064]

[0065] in, The local current density on the cathode surface. The molar mass of platinum, The number of electrons in the platinum deposition reaction and =2, It is Faraday's constant. The density of platinum, This refers to the electroplating time.

[0066] In this embodiment, the special irregular anode has one of the following structural types: full-surface conformal wrapping type, open-back conformal type, front and rear edge shielded conformal type, front and rear edge extended half-covering type, and split-type leaf basin with double-sided conformal type.

[0067] When the structure of the special irregular anode is a conformal wrapping type covering the entire blade surface, the structure is an integral closed shell, and its inner contour maintains a preset distance from the blade base, blade back, leading edge and trailing edge of the entire blade surface, and the surface has no openings.

[0068] When the structure of the special irregular anode is a blade back opening conformal type, the structure is based on the conformal covering structure of the entire blade surface, and multiple sets of elliptical convection holes are opened in the non-critical area of ​​the blade back, which are evenly distributed along the axial and circumferential directions.

[0069] When the structure type of the special irregular anode is a front and rear edge shielded blade conformal type, the structure adopts an integrated conformal shell structure formed by hollowing out the blade blade profile proportionally. The inner contour maintains a preset distance from the entire blade blade profile. The front and rear edge areas of the shell are insulated and shielded to form non-conductive areas, and only the blade basin side and blade back side areas are conductive working surfaces.

[0070] When the structure of the special irregular anode is a semi-enclosed leaf back type with front and rear edge extension, the main body of the structure is a leaf back side conformal conductive plate, whose front and rear edge boundaries extend along the circumference of the leaf towards the leaf basin side, covering the leaf basin side edge area of ​​the front and rear edges, and the middle of the leaf basin is completely open.

[0071] When the structure of the special irregular anode is a split-type leaf basin and leaf back double-sided conformal type, the structure includes a leaf basin side conformal anode plate and a leaf back side conformal anode plate. The leaf basin side conformal anode plate and the leaf back side conformal anode plate maintain a preset distance from the leaf basin surface and the leaf back surface of the blade, respectively, and there is no connecting structure between the front and rear edges.

[0072] This embodiment also provides a special irregular-shaped anode device for platinum plating of a single turbine guide vane, including a special irregular-shaped anode body. The special irregular-shaped anode body is manufactured after the design parameters are determined by the above-mentioned method. The special irregular-shaped anode body is the only working anode of the electroplating system. Its structure is a conformal shell adapted to the outer contour of the single turbine guide vane. The distance between its inner contour and the outer surface of the blade body is 10mm to 30mm. It only covers the working area of ​​the blade body, and the upper and lower edge plates and mounting edges of the blade are completely exposed. The special irregular-shaped anode body is configured to be connected to the positive terminal of a DC power supply.

[0073] A method for plating a single turbine guide vane with platinum includes the following steps: arranging a special shaped anode body according to the above-mentioned apparatus; connecting the special shaped anode body to the positive terminal of a DC power supply, and connecting the single turbine guide vane to be plated to the negative terminal of a DC power supply; performing constant current electroplating on the single turbine guide vane in an electrolyte to obtain a platinum coating with uniform thickness across the entire surface.

[0074] All embodiments use a complete 3D model of a single turbine guide vane of the same type of aero-engine, fully preserving all external manufacturing features such as the blade body, upper and lower edge plates, and mounting edges. Simulation calculations were performed using the electroplating module of COMSOL Multiphysics software. The electroplating time for all schemes was set to 600s, and the cathode boundary condition for all schemes was uniformly set to 100A / m. 2 The average current density varies only with the anode structure. The "average current density" listed in the table is the actual average current density value of the cathode surface obtained from simulation calculations. The slight differences are normal physical phenomena caused by the differences in electric field distribution due to different anode structures.

[0075] General simulation parameter settings: The electrolyte is platinum sulfamate plating solution, the conductivity is set to 10 S / m, and the operating temperature is 30℃; a boundary condition of 100 A / m² average current density is applied to the cathode surface; a boundary condition of 0 V potential (reference potential zero point) is applied to the anode surface; electrode reaction kinetic parameters: the equilibrium potential of the platinum deposition reaction at the cathode is 1.19 V, and the exchange current density is 1 A / m². 2The transfer coefficient is 0.5; the equilibrium potential of the oxygen evolution reaction at the anode is 1.23V, and the exchange current density is 1×10⁻⁶. -4 A / m 2 The transfer coefficient is 0.5.

[0076] Mesh generation strategy: The entire computational domain is discretized using a free tetrahedral mesh, with finer meshes on the cathode blade and anode surfaces. The minimum element size is 0.5 mm, and the maximum element size is 5 mm. A gradient mesh is used in the electrolyte domain, with denser meshes near the electrodes and sparser meshes further away. The total number of mesh elements is determined based on the balance between computational accuracy and efficiency.

[0077] Comparative Example 1:

[0078] This comparative example serves as a baseline simulation to obtain baseline data on coating distribution under conventional flat plate anode conditions, quantitatively identify core technical defects in the electroplating of single turbine guide vanes, and provide a benchmark for all irregular anode schemes.

[0079] Step 1: Construct the geometric model of the electroplating system

[0080] Establish a geometric model of a conventional flat-plate anode electroplating system, as shown in the attached figure. Figure 1 As shown, the model includes a complete single-stage turbine guide vane cathode, a rectangular flat anode, and a cuboid electrolyte domain. The size of the flat anode is determined based on the projected area of ​​the blade, ensuring complete coverage of the blade's projected area, and is positioned at a predetermined distance directly in front of the blade. The size of the electrolyte domain is determined based on the blade size and anode arrangement, ensuring sufficient boundary distance to eliminate boundary effects.

[0081] Step 2: Run the simulation and identify defects

[0082] Mesh generation and steady-state solution were performed using general simulation parameters, resulting in the potential distribution and current density streamlines of the electrolyte domain, as shown in the attached figure. Figure 7 As shown in the attached figure, the thickness distribution of the coating on the cathode surface is as follows. Figure 8 As shown. The quantification results are: maximum coating thickness 224 μm, minimum coating thickness 0.534 μm, average coating thickness 2.7280 μm, coating thickness variance 4.0677, and the calculated actual average current density on the cathode surface is 96.471 A / m².

[0083] Results Analysis: Under conventional flat plate anodizing conditions, the current density is highly concentrated in the tip regions of the leading and trailing edges of the blades, resulting in coating thicknesses far exceeding process requirements, exceeding 82 times the average thickness. In the middle of the blade basin, due to the current shielding effect, coating deposition is almost impossible, with a thickness of less than 0.6 μm. Significant current concentration also exists in the transition zone between the blade edge and the blade body, with coating thicknesses reaching 5 to 10 times the average thickness. The coating distribution across the entire surface is extremely uneven, completely failing to meet the electroplating quality requirements for aero-engine guide vanes. In actual production, the yield of blades using conventional flat plate anodizing processes is only 30% to 40%. Many blades require reworking due to excessively thick coatings, or are scrapped entirely due to excessively thin coatings, resulting in extremely high production costs.

[0084] Example 1:

[0085] This embodiment is the theoretically optimal benchmark scheme, verifying the effect of the full-surface conformal structure on improving the coating uniformity of a single blade, representing the upper limit of the performance of conformal anodes.

[0086] Step 1: Introduce the full-surface conformal anode model of the blade.

[0087] In the geometric model of Comparative Example 1, the anode is replaced with a conformal-wrapped anode covering the entire blade surface, as shown in the attached figure. Figure 2 As shown. The anode is a one-piece closed shell structure, with its inner contour maintaining a preset distance from the entire blade profile. It completely covers the blade base, blade back, leading edge, and trailing edge, covering only the working area of ​​the blade, while the upper and lower edge plate areas are completely open. The anode material is iridium-tantalum-titanium, with a thickness of 3mm, and serves as the sole working anode directly connected to the positive terminal of the power supply. This distance ensures sufficient electric field confinement strength while avoiding installation and positioning difficulties and localized electric field distortion caused by excessively small gaps.

[0088] Step Two: Simulation Results and Analysis

[0089] The solution was rerun using general simulation parameters, and the potential distribution and current density streamlines in the electrolyte domain were obtained as shown in the attached figure. Figure 9 As shown in the attached figure, the thickness distribution of the coating on the cathode surface is as follows. Figure 10 As shown. The quantification results are: maximum coating thickness 20.5 μm, minimum coating thickness 0.572 μm, average coating thickness 2.8226 μm, coating thickness variance 1.7342, and the calculated actual average current density on the cathode surface is 99.816 A / m².

[0090] Results Analysis: The conformal coating anode, by matching the pre-set distance to the full blade profile, achieves precise constraint of the electric field across the entire cathode surface range. The coating thickness variance is reduced by 57.4% compared to conventional flat anodes, making it the theoretically most uniform of all proposed solutions. However, this fully enclosed structure has certain engineering drawbacks: firstly, the tooling installation is difficult, requiring high-precision coaxial clamping, making blade loading and unloading inconvenient; secondly, the anode material consumption is large, resulting in high processing costs. Therefore, this solution is only suitable for small-batch production of core blades with extremely high coating quality requirements.

[0091] Example 2:

[0092] This embodiment is an engineering improvement on the full-coverage scheme. By optimizing the anode structure through openings on the blade back, it improves engineering practicality while maintaining high uniformity.

[0093] Step 1: Introduce the leaf back opening type fully conformal anode model

[0094] In the geometric model of Comparative Example 1, the anode is replaced with a fully conformal anode with an opening on the back of the blade, as shown in the attached figure. Figure 3 As shown, this anode features a conformal coating structure covering the entire blade profile, with multiple sets of elliptical convection holes in non-critical areas on the blade back. The opening ratio is determined based on the electric field distribution and electrolyte convection requirements, while the hole size is determined based on the anode structure dimensions. These opening parameters effectively reduce anode weight and material costs without significantly affecting the overall electric field distribution.

[0095] Step Two: Simulation Results and Analysis

[0096] The solution was rerun using general simulation parameters, and the potential distribution and current density streamlines in the electrolyte domain were obtained as shown in the attached figure. Figure 11 As shown in the attached figure, the thickness distribution of the coating on the cathode surface is as follows. Figure 12 As shown. The quantification results are: maximum coating thickness 15.9 μm, minimum coating thickness 0.558 μm, average coating thickness 2.8144 μm, coating thickness variance 1.7901, and the calculated actual average current density on the cathode surface is 99.528 A / m².

[0097] Results analysis: Opening holes only in non-critical areas on the blade back has a negligible impact on coating uniformity (variance increases by only 3.2%), while significantly reducing the amount of anode material used, thus lowering processing difficulty and cost. This solution retains the high uniformity advantage of the full-surface conformal structure while significantly improving engineering practicality and is suitable for most industrial production scenarios.

[0098] Example 3:

[0099] This embodiment represents the optimal solution in terms of overall performance, achieving the best balance between coating uniformity and engineering practicality, making it the first choice for mass industrial production.

[0100] Step 1: Introduce the leading and trailing edge shielded conformal anode model of the blade.

[0101] In the geometric model of Comparative Example 1, the blade is replaced with a conformal anode with leading and trailing edge shielding, as shown in the attached figure. Figure 4 As shown, the anode employs a one-piece conformal shell structure formed by hollowing out a proportionally enlarged blade profile, with its inner contour maintaining a preset distance from the entire blade profile. The leading and trailing edges of the shell are insulated and shielded to form non-conductive areas, with only the blade head and blade back sides serving as conductive working surfaces. This design effectively suppresses the tip effects at the leading and trailing edges while ensuring the electric field confinement capability of the blade head and blade back regions.

[0102] Step Two: Simulation Results and Analysis

[0103] The solution was rerun using general simulation parameters, and the potential distribution and current density streamlines in the electrolyte domain were obtained as shown in the attached figure. Figure 13 As shown in the attached figure, the thickness distribution of the coating on the cathode surface is as follows. Figure 14 As shown. The quantification results are: maximum coating thickness 13.9 μm, minimum coating thickness 0.529 μm, average coating thickness 2.8261 μm, coating thickness variance 1.7416, and the calculated actual average current density on the cathode surface is 99.941 A / m².

[0104] Results Analysis: This scheme eliminates the tip effect at the leading and trailing edges through insulation shielding treatment of the leading and trailing edge regions, achieving the lowest maximum coating thickness among all schemes (13.9 μm); simultaneously, the current efficiency reaches 99.941%, close to the theoretical value of 100 A / m², with no current waste. Compared with the fully conformal anode, this scheme has moderate structural processing difficulty and optimal overall performance, making it the preferred scheme for mass production recommended by this invention.

[0105] Example 4:

[0106] This embodiment is a low-cost basic solution, suitable for application scenarios with general uniformity requirements.

[0107] Step 1: Introduce the leading and trailing edge extended leaf back semi-enclosed anode model

[0108] In the geometric model of Comparative Example 1, the anode is replaced with a semi-enclosed anode that extends along the leading and trailing edges of the blade, as shown in the attached figure. Figure 5 As shown, the anode body is a conformal conductive plate on the back side of the blade, with its leading and trailing edges extending circumferentially towards the leaf basin. These edges extend a predetermined length, covering the leaf basin edge regions of the leading and trailing edges, leaving the center of the leaf basin completely open. This extension length effectively suppresses the tip effect while preventing increased current shielding in the center of the leaf basin.

[0109] Step Two: Simulation Results and Analysis

[0110] The solution was rerun using general simulation parameters, and the potential distribution and current density streamlines in the electrolyte domain were obtained as shown in the attached figure. Figure 15 As shown in the attached figure, the thickness distribution of the coating on the cathode surface is as follows. Figure 16 As shown. The quantification results are: maximum coating thickness 25.7 μm, minimum coating thickness 0.487 μm, average coating thickness 2.7913 μm, coating thickness variance 1.8486, and the calculated actual average current density on the cathode surface is 98.709 A / m².

[0111] Results Analysis: This design, through its leading and trailing edge extension structure, effectively suppresses the tip effect to a certain extent, reducing the coating thickness variance by 54.6% compared to conventional flat anodes, thus meeting the process requirements of low-end blades. Compared to other irregularly shaped anodes, this design has the simplest structure, uses only 65% ​​of the anode material of full-surface designs, and has the lowest processing cost. It is suitable for cost-sensitive pre-plating processes and low-end blade production, and can also be used as a pre-plating anode for other high-precision designs.

[0112] Example 5:

[0113] This embodiment is a split-structure verification scheme to explore the potential advantages of independent control on both sides.

[0114] Step 1: Introduce a split-type leaf basin with double-sided conformal anode model on the leaf back.

[0115] In the geometric model of Comparative Example 1, the leaf basin is replaced with a split-type leaf basin with double-sided conformal anodes on the leaf back, as shown in the attached figure. Figure 6 As shown, the anode consists of two independent components: a conformal anode plate on the blade base side and a conformal anode plate on the blade back side. These components maintain a preset distance from the blade base profile and blade back profile, respectively, with no connecting structures at the leading and trailing edges. Each anode plate is connected to the positive terminal of the power supply via an independent conductive rod, allowing for individual adjustment of the spatial distance from the blade and the operating current density.

[0116] Step Two: Simulation Results and Analysis

[0117] The solution was rerun using general simulation parameters, and the potential distribution and current density streamlines in the electrolyte domain were obtained as shown in the attached figure. Figure 17 As shown in the attached figure, the thickness distribution of the coating on the cathode surface is as follows. Figure 18 As shown. The quantification results are: maximum coating thickness 121 μm, minimum coating thickness 0.583 μm, average coating thickness 2.6770 μm, coating thickness variance 2.9794, and the calculated actual average current density on the cathode surface is 94.668 A / m².

[0118] Results Analysis: Simulation results at standard current density show that the split structure leads to new electric field concentration points at the leading and trailing edge openings, causing excessive current line concentration at the opening edges, resulting in a maximum coating thickness of 121 μm, which does not meet performance expectations. However, the split structure has unique potential advantages: by independently adjusting the current density of the anodes on the blade base and blade back sides, the coating thickness on the blade base and blade back can be precisely balanced. Therefore, this scheme has great potential for improvement, providing a clear structural basis and simulation platform for future independent current control technology.

[0119] The comparison results of the maximum / minimum coating thickness for all schemes are shown in the appendix. Figure 19 As shown in the figure, it can be clearly seen that the maximum coating thickness of conventional flat anodes is as high as 224 μm, while the maximum coating thickness of all irregular anodes is reduced to below 26 μm, a reduction of 88.5% to 93.8%; the minimum coating thickness of all schemes is stable between 0.48 and 0.58 μm, indicating that while the irregular anodes significantly reduce the maximum thickness, they do not exacerbate the current shielding problem in the middle of the blade basin.

[0120] The results comparing the variance of platinum coating thickness for all schemes are attached. Figure 20 As shown in the figure, it can be clearly seen that the variance of conventional flat anodes is as high as 4.0677, while the variances of the first four types of irregular anodes are all stable between 1.73 and 1.85, with uniformity improved by more than 50%. Among them, the variance of the anode with full blade conformal coverage is the lowest at 1.7342, while the variance of the anode with leading and trailing edge shielding is only 0.4% higher, but its engineering practicality is significantly better.

[0121] Comprehensive Application Selection Guide:

[0122] Different anode solutions can be selected based on different production needs:

[0123] For large-scale industrial production, the leading and trailing edge shielded blade conformal anode is the preferred choice, as it has the best overall performance and the lowest cost.

[0124] For small-batch core blades with extremely high requirements for coating quality, a fully conformal anode with an opening on the blade back can be selected. Its uniformity is close to the theoretical optimal and it has strong engineering applicability.

[0125] For pre-plating processes and low-end blade production, the semi-enclosed anode with extended leading and trailing edges on the blade back can be selected, which has the lowest cost.

[0126] For future high-precision processes, further research can be conducted on the independent current control technology of the double-sided conformal anodes on the back of the split blade basin.

[0127] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for designing a special irregular anode for platinum plating on a single turbine guide vane based on electrochemical simulation, characterized in that, The method includes the following steps: S1: Obtain a three-dimensional geometric model of a single turbine guide vane, fully preserving all external structural features of the blade surface, upper and lower edge plates, and mounting edges; construct a geometric model of an electroplating system including a cathode, anode, and electrolyte domain, wherein the cathode is the single turbine guide vane to be electroplated; S2: Establish an electrochemical simulation environment, adopt a secondary current distribution model, and set electrochemical simulation parameters, including electrolyte conductivity, equilibrium potential and exchange current density of the cathode platinum deposition reaction, and equilibrium potential and exchange current density of the anode oxygen evolution reaction. S3: Using a conventional flat anode as the initial anode, run an electroplating process simulation to obtain the current density distribution and coating thickness distribution on the surface of a single turbine guide vane, and quantitatively identify the core areas with uneven coating thickness. S4: Introduce a special irregular anode model to replace the conventional flat anode in the geometric model. The special irregular anode adopts a conformal shell structure that is adapted to the outer contour of the single turbine guide vane. Its inner contour maintains a preset distance from the outer surface of the blade. Adjust the profile parameters and spatial position parameters of the special irregular anode, and rerun the simulation to obtain the optimized coating distribution data. S5: Using the coating thickness variance as the objective function, determine the design scheme of the special irregular anode through parameter iteration optimization, and output its geometric parameters, profile and spatial coordinates.

2. The method according to claim 1, characterized in that, In step S2, the equilibrium potential of the cathode platinum deposition reaction is 1.05–1.25 V, the exchange current density is 0.5–2 A / m², and the transfer coefficient is 0.4–0.6; the equilibrium potential of the anodic oxygen evolution reaction is 1.15–1.30 V, and the exchange current density is 0.5 × 10⁻⁶. -4 ~2×10 -4 A / m², with a transfer coefficient of 0.4 to 0.

6.

3. The method according to claim 1, characterized in that, In step S2, the electrolyte is a water-soluble platinum salt solution with a conductivity range of 10~20 S / m and a temperature of 25~35℃; the water-soluble platinum salt plating solution is selected from at least one of the following: platinum aminosulfonic acid plating solution, dinitrosodiamine platinum plating solution, chloroplatinic acid plating solution, platinum sulfate plating solution, and hydroxyethylenediamine platinum plating solution.

4. The method according to claim 1, characterized in that, In steps S3 and S4, the coating thickness δ is calculated according to Faraday's law using the following formula: in, The local current density on the cathode surface. The molar mass of platinum, The number of electrons in the platinum deposition reaction and =2, It is Faraday's constant. The density of platinum, This refers to the electroplating time.

5. The method according to claim 1, characterized in that, In step S4, the structure type of the special irregular anode is one of the following: full-surface conformal wrapping type, open-back conformal type, front and rear edge shielded conformal type, front and rear edge extended semi-wrapped type, and split-type leaf basin with double-sided conformal type.

6. The method according to claim 5, characterized in that, When the structure of the special irregular anode is a conformal wrapping type covering the entire blade surface, the structure is an integral closed shell, and its inner contour maintains a preset distance from the blade base, blade back, leading edge and trailing edge of the entire blade surface, and the surface has no openings. When the structure of the special irregular anode is a blade back opening conformal type, the structure is based on the conformal covering structure of the entire blade surface, and multiple sets of elliptical convection holes are opened in the non-critical area of ​​the blade back, which are evenly distributed along the axial and circumferential directions. When the structure type of the special irregular anode is a front and rear edge shielded blade conformal type, the structure adopts an integrated conformal shell structure formed by hollowing out the blade blade profile proportionally. The inner contour maintains a preset distance from the entire blade blade profile. The front and rear edge areas of the shell are insulated and shielded to form non-conductive areas, and only the blade basin side and blade back side areas are conductive working surfaces. When the structure of the special irregular anode is a semi-enclosed leaf back type with front and rear edge extension, the main body of the structure is a leaf back side conformal conductive plate, whose front and rear edge boundaries extend along the circumference of the leaf towards the leaf basin side, covering the leaf basin side edge area of ​​the front and rear edges, and the middle of the leaf basin is completely open. When the structure of the special irregular anode is a split-type leaf basin and leaf back double-sided conformal type, the structure includes a leaf basin side conformal anode plate and a leaf back side conformal anode plate. The leaf basin side conformal anode plate and the leaf back side conformal anode plate maintain a preset distance from the leaf basin surface and the leaf back surface of the blade, respectively, and there is no connecting structure between the front and rear edges.

7. The method according to claim 6, characterized in that, The preset spacing is 10mm to 30mm.

8. The method according to claim 1, characterized in that, In steps S1 and S4, a free tetrahedral mesh is used to discretize the entire computational domain, with the cathode blade surface and the anode surface having their meshes refined.

9. A special-shaped anode device for platinum plating of single turbine guide vanes, characterized in that, The system includes a special-shaped anode body, which is manufactured by determining the design parameters using the method described in any one of claims 1 to 8; the special-shaped anode body is the only working anode of the electroplating system, and its structure is a conformal shell adapted to the outer contour of the single turbine guide vane, with the distance between its inner contour and the outer surface of the blade body being 10mm to 30mm, covering only the working area of ​​the blade body, and the upper and lower edge plates and mounting edges of the blade being fully exposed; the special-shaped anode body is configured to be connected to the positive terminal of a DC power supply.

10. A method for platinum plating a single turbine guide vane, characterized in that, The process includes the following steps: arranging a special-shaped anode body according to the apparatus of claim 9; connecting the special-shaped anode body to the positive terminal of a DC power supply and connecting the single turbine guide vane to be plated to the negative terminal of a DC power supply; and performing constant current electroplating on the single turbine guide vane in an electrolyte to obtain a platinum coating with uniform thickness across the entire surface.

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