Curvature-adapted continuous gradient thickening pt modified aluminide coating and method of making

Abstract

The application discloses a curvature-adaptive continuous gradient thickening Pt modified aluminide coating and a preparation method thereof, and relates to the technical field of high-temperature protective coating preparation. The preparation method of the coating is as follows: three-dimensional topography data or cross-section profile data of a nickel-based high-temperature alloy component is obtained, and surface local curvature is calculated; a Pt deposition target thickness function is established according to the local curvature; a curvature-adaptive Pt initial deposition layer is formed on the surface of the component by adopting step-by-step shielding magnetron sputtering; local thickness mutation between adjacent curvature regions is weakened by adopting multi-stage pulse reverse Pt electroplating for continuous deposition; and a Pt modified aluminide coating is formed through diffusion annealing and embedded aluminizing treatment. The thickness of the coating continuously transits along the surface of the component, presents a continuous gradient thickness distribution matched with the local curvature, can improve the formation and retention capacity of an Al2O3 type protective thermal growth oxide layer in a tip region, and thus improves the oxidation resistance, spalling resistance and high-temperature service stability of the nickel-based high-temperature alloy component with complex curvature.

Description

Technical Field

[0001] This invention relates to a curvature-adaptive, continuously gradient-thickened Pt-modified aluminide coating and its preparation method, belonging to the field of high-temperature protective coating preparation technology. Background Technology

[0002] Nickel-based superalloys are widely used in hot-end components of aero-engines and gas turbines due to their excellent high-temperature strength, creep resistance, and microstructural stability. As service temperatures increase, turbine blades, guide vanes, and combustion chamber components are subjected to long-term high-temperature oxidation, hot corrosion, and thermomechanical loads, making their surfaces prone to oxide film cracking, peeling, and interface degradation, thus affecting their service life. To improve their high-temperature protection performance, aluminide coatings or Pt-modified aluminide coatings are typically prepared on the surface of nickel-based superalloys.

[0003] However, actual hot-end components are usually not simple planar structures, but typically possess significant and complex curvature characteristics. For example, turbine blade tips, leading edges, trailing edges, small-radius transition zones, chamfered areas, and locally protruding areas are all typical tip regions or high-curvature regions. On the one hand, tip regions or high-curvature regions are not easily uniformly treated by mechanical grinding or conventional polishing methods, which can easily lead to problems such as insufficient grinding, local scratches, uneven surface roughness, or blunting of the tip contour, and may also leave residual oxide films, processing contamination layers, or local passivation films. In addition, tip regions or high-curvature regions are more prone to problems such as accelerated Al consumption, local instability of thermally grown oxides, rapid expansion of interdiffusion zones, and inward penetration of the outer oxide / diffusion zone during high-temperature oxidation. If a Pt-modified aluminide coating design with a uniform thickness across the entire surface is adopted, it is difficult to achieve the same coating thickness in low-curvature regions and high-curvature regions while simultaneously meeting the requirements for precious metal usage control in low-curvature regions and anti-stripping and anti-oxidation in extremely high-curvature regions.

[0004] Current methods for preparing Pt-modified aluminide coatings often aim for uniform coating thickness across the entire surface or focus only on the coating quality in planar areas. However, for components with complex curvature, high-curvature regions are prone to localized current density concentrations during Pt electroplating. If left uncontrolled, this can easily lead to overplating, burning, nodular deposition, and abrupt thickness changes. Conversely, completely suppressing the thickening of high-curvature regions may result in insufficient effective protective layer thickness in the tip areas, making it difficult to meet the local stability requirements in high-temperature oxidizing environments.

[0005] Therefore, the Pt-modified aluminide coating on nickel-based superalloy components with complex curvature should not simply pursue uniform thickness across the entire surface. Instead, a continuously varying thickness structure should be established based on the local curvature, so that the high curvature region obtains a Pt-modified aluminide layer that is appropriately thickened and continuously dense relative to the low curvature region.

[0006] Several technical solutions related to Pt electroplating and Pt-modified aluminide coatings for nickel-based superalloys already exist. For example, CN108130566A discloses an electroplating solution and method for electroplating platinum layers on nickel-based superalloy surfaces, mainly used to improve the porosity, burrs, thickness uniformity, and peeling / cracking problems of conventional surface Pt layers. CN101358351A discloses a method for preparing a nano-platinum-aluminum anti-oxidation coating for superalloys, which includes superalloy surface treatment, Pt electroplating, and powder embedding aluminizing treatment. CN105624522A discloses a single-phase platinum-modified aluminide coating and its preparation process, mainly used to obtain a β-(Ni,Pt)Al single-phase coating. CN115976586A discloses a forward and reverse pulse electrolytic nickel-tungsten alloy solution, its preparation method, electroplating method, and a nickel-tungsten alloy coating. While the aforementioned technologies involve Pt electroplating, Pt-Al or β-(Ni,Pt)Al coatings, forward and reverse pulsed electroplating, and pulsed laser-assisted plating processes, their focus is not on establishing a continuously thickened Pt deposition layer based on the local curvature of complex curved components, nor on controlling the deposition rate and surface morphology of high-curvature regions through multi-stage pulsed reverse Pt electroplating and reverse leveling charge ratio. Therefore, it is necessary to provide a method for preparing Pt-modified aluminide coatings suitable for the tip or high-curvature regions of complex-curvature nickel-based superalloys to improve the anti-stripping properties, oxidation resistance, and high-temperature service stability of these regions. Summary of the Invention

[0007] To address the shortcomings of related technologies, this invention provides a curvature-adaptive, continuously gradient thickened Pt-modified aluminide coating and its preparation method. The coating thickness transitions continuously along the surface of the component, exhibiting a continuous gradient thickness distribution that matches the local curvature. This improves the formation and retention of the Al2O3-type protective thermally grown oxide layer in the tip region, thereby enhancing the oxidation resistance, spalling resistance, and high-temperature service stability of nickel-based superalloy components with complex curvature. It solves the problems that when Pt-modified aluminide coatings are designed with a uniform thickness across the entire surface, insufficient spalling resistance, local instability of the protective oxide film, and decreased cross-sectional integrity after high-temperature oxidation are prone to occur in the tip region or extremely high curvature region.

[0008] One objective of this invention is to provide a method for preparing a curvature-adaptive, continuously gradient-thickened Pt-modified aluminide coating, specifically comprising the following steps: (1) Calculate the local curvature of the surface of the nickel-based superalloy component by using the three-dimensional topographic data or cross-sectional profile data of the nickel-based superalloy component with a complex curvature surface.

[0009] (2) Establish the target thickness function of Pt pre-deposited layer based on the local curvature of the surface of nickel-based high-temperature alloy component, and determine the initial deposition thickness of Pt and the cumulative magnetron sputtering time in different local curvature regions.

[0010] (3) The surface of the nickel-based superalloy component is pretreated, and then a Pt initial deposition layer with curvature matching is formed on the surface of the pretreated nickel-based superalloy component by step-by-step shielded magnetron sputtering.

[0011] (4) Multi-stage pulse reverse Pt electroplating is used to supplement the initial Pt deposition layer to obtain a nickel-based high-temperature alloy component with a Pt electrochemical leveling deposition layer on the surface.

[0012] (5) Diffusion annealing and embedding aluminizing treatment are performed on nickel-based superalloy components with Pt electrochemical leveling deposition layers on the surface to obtain a Pt modified aluminide coating with curvature-adapted continuous gradient thickening on the surface of the nickel-based superalloy.

[0013] Preferably, the formula for calculating the local curvature of the nickel-based superalloy component surface in step (1) is: Where x is the abscissa function of the component surface profile, in mm; y is the ordinate function of the component surface profile, in mm; and κ is the local curvature, in mm. -1 x′ and y′ are the first derivatives of x and y, respectively, and are dimensionless. x″ and y″ are the second derivatives of x and y, respectively, and are in mm. -1 .

[0014] More preferably, the nickel-based superalloy component with a complex curvature surface in step (1) refers to a nickel-based superalloy component with a pointed region or a high curvature region; the high curvature region is 1 mm. -1 ≤κ<5mm -1 The tip region κ ≥ 5mm -1 .

[0015] More preferably, the nickel-based superalloy component in step (1) is one of GH4099 nickel-based superalloy, directionally solidified nickel-based superalloy, single-crystal nickel-based superalloy, or equiaxed nickel-based superalloy.

[0016] Preferably, the target thickness function of the Pt pre-deposited layer in step (2) is: , where d * Pt (κ) represents the target deposition thickness at the local curvature κ, in μm, d min The lower limit of the target thickness for Pt pre-deposition in low curvature regions, in μm, d max κ0 represents the upper limit of the target thickness for Pt pre-deposition in the extremely high curvature region, in μm, and κ0 is the curvature adjustment parameter, in mm. -1 , where n is the dimensionless curvature sensitivity index.

[0017] More preferably, the d min 2~4μm, dmax The value is 6~10μm, and the value of κ0 is 0.5~5mm. -1 The value of n is 0.5 to 2.0.

[0018] Preferably, the formula for determining the cumulative magnetron sputtering time in step (2) is: , where t s (κ) represents the cumulative magnetron sputtering time at the local curvature κ, in seconds (s) and d. * Pt (κ) represents the target deposition thickness at the local curvature κ, in μm, v s η represents the magnetron sputtering deposition rate, expressed in μm / s. s The initial deposition proportion undertaken during the magnetron sputtering stage is a dimensionless proportionality coefficient, ranging from 0.02 to 0.20.

[0019] More preferably, the cumulative magnetron sputtering time in the low curvature region is 10-60 s, the cumulative magnetron sputtering time in the transition curvature region (i.e., the medium curvature region) is 60-180 s, and the cumulative magnetron sputtering time in the tip region or high curvature region is 180-600 s.

[0020] More preferably, the tip region or high curvature region includes one or more of the following: blade tip, leading edge, trailing edge, small radius transition region, chamfered region, or local protrusion region; when using cross-sectional profile data, the local curvature can be calculated based on the component surface profile coordinate function.

[0021] More preferably, the pretreatment method in step (3) is as follows: degreasing the surface of the nickel-based high-temperature alloy component (e.g., using an alkaline degreasing solution containing NaOH, Na2CO3 and surfactants), acid washing activation, cleaning (e.g., using deionized water for cleaning), and drying treatment.

[0022] More preferably, the alkaline degreasing solution contains NaOH at a concentration of 5-30 g / L, Na2CO3 at a concentration of 5-30 g / L, surfactant (OP-10) at a concentration of 0.5-5 g / L, and deionized water as the solvent; the degreasing temperature is 40-70°C, and the degreasing time is 5-30 min; the acid pickling activation is performed using an acid pickling activation solution, which is prepared from an acid stock solution and deionized water, wherein the acid stock solution is composed of one or more of concentrated hydrochloric acid, concentrated phosphoric acid, concentrated sulfuric acid, or hydrofluoric acid; based on the total volume of the acid pickling activation solution being 100%, the amount of acid stock solution added to the acid pickling activation solution is 5%-35% by volume percentage, with the remainder being deionized water; the acid pickling activation time is 1-5 min; after acid pickling activation, the solution is washed with deionized water, followed by drying treatment at a temperature of 40-80°C for a time of 5-30 min.

[0023] In the acid stock solution used for pickling and activation in this invention, concentrated hydrochloric acid, concentrated phosphoric acid, concentrated sulfuric acid, and hydrofluoric acid are all commercially available standard products.

[0024] Before forming the curvature-adaptive Pt initial deposition layer, the present invention performs pulsed laser micro-region activation treatment on the tip region or high curvature region.

[0025] Preferably, step (4) employs a tip-adapted multi-stage pulsed reverse Pt electroplating process for supplementary deposition; the tip-adapted multi-stage pulsed reverse Pt electroplating process sequentially includes a low-current nucleation stage, a stable deposition stage, a reverse leveling stage, and an open-circuit diffusion recovery stage, wherein the forward pulse current density of the low-current nucleation stage is 0.1~0.5 A / dm. 2 The positive pulse width is 10~100ms, the duty cycle is 10~40%, the processing time is 1~10min, and the positive pulse current density during the stable deposition stage is 0.5~1.5A / dm³. 2 The forward pulse width is 50~300ms, the duty cycle is 30~70%, the deposition time is 10~120min, and the reverse pulse current density in the reverse leveling stage is 0.05~1.5A / dm². 2 The reverse pulse width is 1~50ms, and the pause time of the open-circuit diffusion recovery phase is 10~500ms.

[0026] More preferably, in the reverse leveling stage, one reverse leveling pulse is applied after every m forward pulses, where m is 5~20; the reverse leveling cycle charge ratio Q r / Q f It ranges from 0.02 to 0.25, where: In the formula, i r This is the absolute value of the reverse pulse current density, in A / dm². 2 , t r i is the reverse pulse width, in milliseconds (ms). f This represents the absolute value of the forward pulse current density during the reverse leveling stage, expressed in A / dm². 2 , t f Q represents the positive pulse width in milliseconds (ms), where m is the number of positive pulses between two adjacent negative leveling pulses. r / Q f It is a dimensionless parameter.

[0027] More preferably, the electroplating solution used in step (4) of the Pt electroplating process is one of the following: dinitrosodiamineplatinum system, platinum aminosulfonate system, tetraammineplatinum salt system or hexahydroxyplatinum salt system.

[0028] More preferably, the effective concentration of Pt in the electroplating solution is 5~20g / L, the pH is 4.0~7.0, and the electroplating temperature is 30~80℃; the thickness of the Pt pre-deposited layer is 3~10μm.

[0029] Preferably, the diffusion annealing process in step (5) is carried out in a protective atmosphere, with a diffusion annealing temperature of 900~1100℃ and a diffusion annealing time of 2~10h.

[0030] More preferably, the protective atmosphere is a mixture of Ar and H2, wherein the hydrogen content is 5% by volume and the balance is argon.

[0031] More preferably, the diffusion annealing temperature is 1050°C and the diffusion annealing time is 8 hours.

[0032] Preferably, in step (5), an aluminizing agent is used for embedding and aluminizing treatment. The composition of the aluminizing agent, by mass percentage, includes: 5-20% Al powder, 1-5% NH4Cl, and the balance is Al2O3. The conditions for embedding and aluminizing treatment are: under an inert atmosphere (such as argon atmosphere), the temperature is kept at 950-1100℃ for 4-12 hours.

[0033] More preferably, the composition of the infiltrator in step (5) includes, by mass percentage: 10% Al, 2% NH4Cl, and the balance being Al2O3; the conditions for the aluminizing treatment are: heat preservation at 1050℃ for 8 hours.

[0034] The local curvature of the present invention is used to determine the initial Pt deposition thickness and cumulative magnetron sputtering time, and further to determine the net Pt electroplating deposition thickness or reverse leveling charge ratio.

[0035] Step (1) of this invention, the calculation of local curvature, can identify low curvature regions, medium curvature regions, and high curvature regions at the tip, wherein the local curvature regions include low curvature regions κ<0.1mm. -1 Medium curvature region 0.1mm -1 ≤κ<1mm -1 The high curvature region at the tip, which also includes a 1mm high curvature region. -1 ≤κ<5mm -1 and tip region κ≥5mm -1 This provides a basis for determining the target thickness of the subsequent Pt pre-deposited layer.

[0036] In step (4) of this invention, to achieve a continuous thickness transition along the surface, the electroplating parameters are not simply set abruptly in a discrete partitioning manner, but can be continuously or quasi-continuously adjusted according to the local curvature variation to achieve the effective deposition amount. The effective deposition amount can be achieved by adjusting the deposition time, the number of pulse cycles, the positive pulse current density, the duty cycle, or a combination thereof. For low curvature regions, a lower effective deposition amount is used; for high curvature regions at the tip, a higher effective deposition amount is used; for transition curvature regions, an effective deposition amount between the two is used. Through the above methods, the Pt pre-deposition thickness can be smoothly increased from the low curvature region to the high curvature region at the tip.

[0037] The surface pretreatment in step (3) of this invention includes pulsed laser micro-area activation treatment applied to a pointed or high-curvature region, or applied to a local surface region including a pointed or high-curvature region; the pulsed laser micro-area activation treatment is performed without significantly altering the macroscopic geometric contour of the nickel-based superalloy component. The pulsed laser power for the pulsed laser micro-area activation treatment is 25~100W, the scanning speed is 45~300mm / s, the pulse frequency is 10~45kHz, the number of scans is 1~5, and the scanning interval is 20~200μm. Further, the pulsed laser power is 50W, the scanning speed is 150mm / s, the pulse frequency is 25kHz, and the number of scans is 2.

[0038] The step-by-step shielding magnetron sputtering in step (3) of this invention includes: performing basic sputtering on the entire surface of the nickel-based superalloy component; shielding the low curvature region and performing additional sputtering on the medium curvature region and the high curvature tip region; shielding the low curvature region and the medium curvature region and performing further additional sputtering on the high curvature tip region; increasing the cumulative magnetron sputtering time of the low curvature region, the medium curvature region and the high curvature tip region in sequence, and increasing the initial Pt deposition amount of the corresponding region with the increase of local curvature.

[0039] In the reverse leveling stage of step (4) of the present invention, the absolute value of the reverse pulse current density is less than, equal to or greater than the absolute value of the forward pulse current density.

[0040] Another objective of this invention is to provide a complex curvature nickel-based superalloy Pt-modified aluminide coating prepared by the method of this invention.

[0041] The complex curvature nickel-based superalloy Pt-modified aluminide coating prepared by this invention comprises, from the outside to the inside, a β-(Ni,Pt)Al platinum-modified aluminide layer, an interdiffusion region, and a nickel-based superalloy substrate; the thickness of the aluminide layer in the high curvature region or the tip region is 2.0 to 4.0 times that in the low curvature region and varies continuously; after the Pt-modified aluminide coating is oxidized in an air atmosphere at 1000℃ for 200 h, a continuous Al2O3-type protective thermally grown oxide layer can be formed in the tip region or the high curvature region, and no continuous cracks penetrating the Pt-modified aluminide layer appear in the tip region or the high curvature region, and the integrity of the coating cross section is maintained.

[0042] Mechanism of the invention: This invention transforms the geometric features of complex curved components into executable electroplating process parameters, enabling the preparation of continuously thickened Pt-modified aluminide coatings. First, the invention obtains the local curvature of the component surface using three-dimensional topography data or cross-sectional profile data, and establishes a target thickness function for the Pt pre-deposition layer based on the local curvature to determine the required target Pt pre-deposition thickness at different curvature locations. Then, based on a conversion, the initial deposition amount is converted into the corresponding cumulative magnetron sputtering time, establishing an initial Pt deposition distribution that varies with the local curvature. Next, multi-stage pulsed reverse Pt electroplating is used to further deposit and densify this deposition distribution. Finally, diffusion annealing and embedding aluminizing transform the continuous thickness difference of the Pt deposition layer into a continuously thickened structure of the final Pt-modified aluminide coating.

[0043] After Pt pre-deposition, diffusion annealing causes Pt to diffuse into the near-surface layer of the nickel-based superalloy. Embedding aluminizing treatment causes Al to react with Pt in the near-surface enrichment layer to form a β-(Ni,Pt)Al platinum-modified aluminide layer. Since the Pt pre-deposited layer has formed a thickness distribution that varies with the curvature gradient along the component surface, by changing the degree of Pt enrichment in the near-surface layer, the Al diffusion reaction interface, and the growth behavior of β-(Ni,Pt)Al, the final Pt-modified aluminide coating is thicker in the tip region or high curvature region than in the low curvature region, and transitions continuously along the component surface.

[0044] The beneficial effects of this invention are: (1) This invention addresses the problem of preferential failure in the tip or high curvature regions of complex-curvature nickel-based superalloy components by preparing a coating. Instead of using the traditional full-surface uniform-thickness Pt-modified aluminide coating structure, it establishes a target thickness function for the Pt pre-deposited layer based on the local curvature of the component surface, so that the Pt pre-deposited thickness continuously increases with the increase of local curvature. A schematic diagram of the nickel-based superalloy component model is shown below. Figure 2 As shown in (a), the curvature distribution diagram of the component model is as follows. Figure 2As shown in (b), this preparation method allows for a lower Pt pre-deposition thickness in low-curvature regions, reducing unnecessary consumption of precious metals. Conversely, higher Pt pre-deposition thicknesses can be achieved in high-curvature regions such as the blade tip, leading edge, trailing edge, and small-radius transition zone, thereby improving the effective Pt / Al reserve and local protection capability in these regions. This method is more suitable for the actual service failure characteristics of complex curvature hot-end components. A schematic diagram of the local curvature of the substrate sample in this embodiment is shown below. Figure 2 As shown in (c) and (d).

[0045] (2) This invention transforms the local curvature of complex curved components from a geometric descriptor into a process control variable during coating preparation. Specifically, through a functional mapping between local curvature and the target Pt deposition thickness, the Pt deposition amount no longer depends on the randomly formed local electric field concentration on the complex curved component, but is predetermined by the component's geometric characteristics. Compared with the full-surface uniform-thickness Pt deposition scheme, this invention can control the amount of noble metal used in low-curvature regions while increasing the Pt / Al reserves in high-curvature regions such as the blade tip, leading edge, trailing edge, and small-radius transition zone, thus better conforming to the local failure characteristics of complex curved hot-end components.

[0046] (3) This invention uses a multi-stage pulsed reverse Pt electroplating process instead of traditional DC Pt electroplating or single forward pulse electroplating to control the Pt deposition process in stages in complex curvature tip regions. The low-current nucleation stage uses a lower forward pulse current density to allow Pt to preferentially form more uniform initial crystal nuclei on the surface of the tip region or high curvature region, avoiding the formation of coarse grains or local protrusions due to excessively high local current density in the early stage of electroplating; the stable deposition stage is used to increase the thickness of the Pt pre-deposited layer on the basis of the formed crystal nuclei, so that the Pt layer gradually and continuously covers the substrate surface; the reverse leveling stage uses a short-time reverse pulse to cause slight anodic dissolution at local protrusions, excessive deposition at the tip, or rough protrusions, thereby weakening Pt over-plating, nodular deposition, and thickness abrupt changes; the open-circuit diffusion recovery stage restores the concentration of Pt complex ions and local pH near the tip region, reducing the risk of concentration polarization and local scorching in the next deposition cycle; through the combination of the above stages, the Pt pre-deposited layer in the tip region can be made more continuous, dense, and with controllable thickness.

[0047] (4) The present invention achieves reverse leveling of the power ratio Q r / Q f By controlling the electrical relationship between forward deposition and reverse leveling, the reverse pulse can weaken localized over-deposition in tip or high-curvature regions, while avoiding excessive reverse dissolution that could disrupt the continuity of the formed Pt pre-deposited layer, thereby reducing the risk of Pt over-plating, scorching, nodular deposition, and abrupt thickness changes. r / Q fWhen the Q value is too small, the reverse leveling effect is insufficient, and excessive local deposition, coating roughening, or nodular protrusions are still prone to occur in the tip area; when Q... r / Q f When the value is too large, the reverse dissolution effect is too strong, which can weaken the continuity of the already formed Pt pre-deposited layer, and even cause local thinning or discontinuity of the Pt layer. This invention will use Q... r / Q f By controlling the pulse strength between 0.02 and 0.25, the reverse pulse can weaken localized excessive deposition in the tip region while avoiding excessive dissolution of the already formed Pt layer. This results in a Pt pre-deposited layer with good continuity, density, and thickness controllability in complex curvature regions. The coating thickness of this invention transitions continuously along the component surface, exhibiting a continuous gradient thickness distribution that matches the local curvature. This improves the formation and retention of the Al2O3-type protective thermally grown oxide layer in the tip region, thereby enhancing the oxidation resistance, spalling resistance, and high-temperature service stability of nickel-based superalloy components with complex curvature. Attached Figure Description

[0048] Figure 1 This is a flowchart illustrating the preparation process of the Pt-modified aluminide coating of this invention.

[0049] Figure 2 This is a schematic diagram of the nickel-based superalloy construction model and a schematic diagram of its partial curvature, wherein... Figure 2 (a) is a schematic diagram of a nickel-based superalloy component model. Figure 2 (b) shows the curvature distribution of the component model. Figure 2 (c~d) are schematic diagrams of the local curvature of the matrix sample in the example.

[0050] Figure 3 This is the XRD pattern of the Pt-modified aluminide coating in Example 1 of the present invention.

[0051] Figure 4 This is a cross-sectional SEM image of the Pt-modified aluminide coating of the present invention after preparation in different curvature regions and oxidation in air at 1000°C for 200 hours. Figure 4 Images (a-b) are cross-sectional SEM images of the Pt-modified aluminide coating prepared in Example 1 after 200 hours of oxidation. Figure 4 Images c-d are cross-sectional SEM images of the Pt-modified aluminide coating prepared in Example 2 after 200 hours of oxidation. Figure 4 The images (e~f) are cross-sectional SEM images of the Pt-modified aluminide coating prepared in Example 3 after oxidation for 200 hours.

[0052] Figure 5 The figures show the oxidation kinetics curves of the coatings in Examples 1-3 and Comparative Example 1 during the high-temperature oxidation process.

[0053] Figure 6 This is a cross-sectional SEM image of the coating of Comparative Example 2 of the present invention.

[0054] Figure 7 This is a cross-sectional SEM image of the coating of Comparative Example 3 of the present invention. Detailed Implementation

[0055] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. In the embodiments and comparative examples of this invention, unless otherwise specified, all chemical reagents used were commercially available analytical grade reagents. The preparation flow chart of the coating of this invention is shown below. Figure 1 As shown.

[0056] Example 1 A method for preparing a curvature-adaptive, continuously gradient-thickened Pt-modified aluminide coating specifically includes the following steps: (1) GH4099 nickel-based superalloy was used as the raw material for nickel-based superalloy components. It was processed into blade-shaped complex curvature specimens. The specimens have a low curvature region, a small radius transition region, and an extremely high curvature region at the tip. The specimen cross-sectional profile data was obtained. Based on the total arc length of the specimen cross-sectional profile curve, it was divided at equal intervals along the arc length direction to obtain 1600 sampling points distributed at equal intervals along the arc length direction. The arc length coordinates s, the transverse coordinates x, and the longitudinal coordinates y of the cross-section were extracted from each sampling point. The local curvature κ of each sampling point was calculated according to the following formula: .

[0057] Based on the κ value of each sampling point, curvature mapping data of the sample surface was established, and the sample surface was divided into four curvature zones according to the local curvature size. The Bin statistical results of the curvature mapping table are shown in Table 1. The low curvature zone in the table is the transition curvature zone, and the medium-high curvature zone and the extremely high curvature zone are the tip zone or the high curvature zone.

[0058] Table 1 (2) Due to the target thickness function d of the Pt pre-deposited layer * Pt (κ) increases monotonically with |κ|. Therefore, for multiple sampling points within the same curvature partition Bin, first take the sampling points within that Bin that contain |κ|. i Substituting the 90th percentile value of | into the target thickness function of the Pt pre-deposited layer: ,Right now Then, based on the proportion η of the magnetron sputtering stage... s Calculate the initial Pt sputtering thickness of the Bin, and calculate the cumulative magnetron sputtering time based on the pre-calibrated effective magnetron sputtering deposition rate in the region: In this embodiment, d min =2.0μm, d max =6.0μm, κ0=0.5mm -1 n=0.5, η s =0.02. Substituting each of the 1600 sampling points in the curvature mapping table into the above formula, and taking the 90th percentile value according to Bin, the calculation results are shown in Table 2.

[0059] Table 2 (3) The sample was placed in an alkaline degreasing solution for degreasing treatment. The alkaline degreasing solution contained 5 g / L NaOH, 5 g / L Na2CO3, and 0.5 g / L OP-10 emulsifier. The solvent was water, the degreasing temperature was 40℃, and the treatment time was 5 min. After degreasing, the sample was washed with deionized water. Then, an 8% (v / v) hydrochloric acid solution prepared from commercially available concentrated hydrochloric acid and deionized water was used as the acid washing activation solution for acid washing activation. The acid washing activation time was 1 min. After acid washing, the sample was washed with deionized water and dried at 40℃ for 5 min. The tip area or high curvature area was subjected to pulsed laser micro-area activation treatment. The laser power was 25W, the scanning speed was 45mm / s, the pulse frequency was 10kHz, the number of scans was 1, and the scanning interval was 20μm. Subsequently, stepwise shielded magnetron sputtering was used to form the initial Pt deposition distribution. Pt target material was used for magnetron sputtering, and argon was used as the working gas. According to the cumulative magnetron sputtering time calculated in Table 2, the low curvature region (Bin1), the medium-low curvature region (Bin2), the medium-high curvature region (Bin3), and the extremely high curvature region (Bin4) were sputtered for 10s, 60s, 180s, and 240s, respectively, so that the initial Pt deposition amount increased with the increase of local curvature, and a curvature-adapted initial Pt deposition layer was formed on the surface of the pretreated sample.

[0060] (4) The sample with the initial Pt deposition layer with the curvature adapted to the surface was used as the cathode, and Pt deposition was continued in the Pt electroplating solution of dinitrosodiammineplatinum system; the effective Pt concentration was 5 g / L, the pH was 4.0, the electroplating temperature was 30℃, and the Pt electroplating adopted the tip-adapted multi-stage pulse reverse process, with the forward pulse current density of 0.1 A / dm during the low current nucleation stage. 2 The positive pulse width was 10 ms, the duty cycle was 10%, and the processing time was 1 min; the positive pulse current density during the stable deposition stage was 0.5 A / dm³. 2 The forward pulse width was 50 ms, the duty cycle was 30%, and the deposition time was 10 min; the reverse pulse current density during the reverse leveling stage was 0.5 A / dm³. 2 The reverse pulse width is 20ms; the pause time during the open-circuit diffusion recovery phase is 10ms. During the reverse leveling phase, one reverse leveling pulse is applied after every m forward pulses; the reverse leveling cycle charge ratio is calculated using the following formula: , change i r =0.5A / dm 2 t r =20ms, i f =0.5A / dm 2 t f Substituting 50ms and m=20 into the above formula, we get Q. r / Q f =0.02, the electroplating stage is used to supplement the Pt deposition amount outside the magnetron sputtering stage, so that the total Pt deposition thickness of each curvature zone is close to the target thickness calculated from the complete curvature table in Table 2; thus, a nickel-based high-temperature alloy component with a Pt electrochemical leveling deposition layer on the surface is obtained.

[0061] (5) The nickel-based superalloy component with Pt electrochemical leveling deposition layer on the surface was placed in a mixed atmosphere of hydrogen and argon (the hydrogen content in the mixed atmosphere was 5% by volume and the balance was argon) for diffusion annealing. The diffusion annealing temperature was 900℃ and the diffusion annealing time was 2h. After diffusion annealing, the sample was completely embedded in aluminizing powder (the composition of the aluminizing powder included 5% Al, 1% NH4Cl and 94% Al2O3 by mass percentage). The temperature was raised to 950℃ under argon atmosphere and held for 4h. A Pt modified aluminide coating with curvature adaptation and continuous gradient thickening was obtained on the surface of the nickel-based superalloy.

[0062] After oxidizing the GH4099 nickel-based superalloy with the obtained Pt-modified aluminide coating in air at 1000℃ for 200 h, a continuous Al2O3 protective thermally grown oxide layer was formed in the high curvature region, maintaining the integrity of the coating cross-section. The oxidation kinetics curve is shown in the figure. Figure 5 As shown, by Figure 5 It can be concluded that the Pt-modified aluminide coating in this embodiment exhibits stable weight gain under long-term high-temperature oxidation and has excellent antioxidant properties.

[0063] The Pt-modified aluminide coating prepared in this embodiment was subjected to XRD testing, and the XRD pattern is shown below. Figure 3 As shown, by Figure 3 It can be concluded that the coating mainly contains PtAl2 phase and NiAl phase, indicating that the process of the example can successfully prepare Pt modified aluminide coating.

[0064] Depend on Figure 4As shown in (a~b), the Pt-modified aluminide coating obtained in Example 1, after oxidation in air at 1000°C for 200 hours, maintains good cross-sectional integrity in both the low-curvature region and the extremely high-curvature tip region. No obvious through-cracks or overall peeling were observed between the outer layer of the coating, the interdiffusion zone, and the substrate, and the surface protective oxide layer was well preserved in different curvature regions. Compared with the low-curvature region, the coating cross-sectional thickness in the extremely high-curvature tip region increased, and maintained a continuous transition along the curved surface contour. This indicates that the step-by-step shielding magnetron sputtering time and subsequent Pt deposition process set according to the local curvature can form a Pt-modified aluminide coating with curvature adaptation on the surface of GH4099 nickel-based superalloy and improve the cross-sectional stability after oxidation at the high-curvature tip.

[0065] Example 2 A method for preparing a curvature-adaptive, continuously gradient-thickened Pt-modified aluminide coating specifically includes the following steps: (1) Directionally solidified nickel-based superalloys were used as raw materials for nickel-based superalloy components. These were processed into blade-shaped complex curvature specimens. The specimens had a low curvature region, a small-radius transition region, and an extremely high curvature region at the tip. The specimen cross-sectional profile data were obtained using the same method as in Example 1. A curvature mapping table was established, including arc length coordinates s, cross-sectional coordinates x and y, local curvature κ, and curvature partitions Bin. All 1600 sampling points along the arc length were substituted point-by-point into the target thickness function of the Pt pre-deposited layer for calculation. The local curvature was calculated using the following formula: Based on the κ value of all sampling points, the sample surface is divided into four curvature zones.

[0066] (2) The cumulative magnetron sputtering time for the four curvature zones is calculated using the same method as in Example 1. In this example, d min =3.0μm, d max =8.0μm, κ0=2.5mm -1 n=1.0, η s =0.10. Substitute each of the 1600 sampling points in the curvature mapping table into the above formula, and take the 90th percentile value according to Bin. The calculation results are shown in Table 3.

[0067] Table 3 (3) The sample was placed in an alkaline degreasing solution for degreasing treatment. The alkaline degreasing solution contained 15 g / L of NaOH, 15 g / L of Na2CO3, and 2.0 g / L of OP-10 emulsifier. The solvent was water. The degreasing temperature was 55℃ and the treatment time was 18 min. After degreasing, the sample was washed with deionized water and then acid-washed and activated with an acid-washing activation solution (the acid-washing activation solution was prepared by mixing concentrated hydrochloric acid, concentrated phosphoric acid and deionized water in a volume ratio of 15:20:65). The acid-washing activation time was 3 min. After acid washing, the sample was rinsed with deionized water and dried at 60℃ for 15 min. The tip or high-curvature region was then subjected to pulsed laser micro-area activation treatment. The pulsed laser power was 50 W, the scanning speed was 150 mm / s, the pulse frequency was 25 kHz, the number of scans was 2, and the scanning interval was 100 μm. Subsequently, stepwise shielded magnetron sputtering was used to form the initial Pt deposition distribution. Pt target material was used for magnetron sputtering, and argon was used as the working gas. According to the cumulative magnetron sputtering time calculated in Table 3, Bin1, Bin2, Bin3, and Bin4 were sputtered for 30 s, 120 s, 300 s, and 420 s respectively, so that the initial Pt deposition amount increased with the increase of local curvature, forming a curvature-adapted initial Pt deposition layer on the surface of the pretreated sample.

[0068] (4) The sample with the initial Pt deposition layer with the curvature adapted to the surface was used as the cathode, and Pt deposition was continued using a platinum aminosulfonate Pt electroplating solution; the effective Pt concentration was 10 g / L, the pH was 5.5, the electroplating temperature was 50 °C, and the Pt electroplating adopted a tip-adapted multi-stage pulse reverse process, with the forward pulse current density of 0.3 A / dm during the low-current nucleation stage. 2 The positive pulse width was 50 ms, the duty cycle was 30%, and the processing time was 5 min; the positive pulse current density during the stable deposition stage was 0.8 A / dm³. 2 The forward pulse width was 100 ms, the duty cycle was 50%, and the deposition time was 60 min; the reverse pulse current density during the reverse leveling stage was 0.8 A / dm³. 2 The reverse pulse width is 30ms; the pause time during the open-circuit diffusion recovery phase is 100ms. During the reverse leveling phase, one reverse leveling pulse is applied after every m forward pulses; the reverse leveling cycle charge ratio is calculated using the following formula: , change i r =0.8A / dm 2 t r =30ms, i f =0.8A / dm 2 t f Substituting 60ms and m=10 into the above formula, we get Q. r / Q f=0.05, the electroplating stage is used to supplement the Pt deposition amount outside the magnetron sputtering stage, so that the total Pt deposition thickness of each curvature zone is close to the target thickness calculated from the complete curvature table in Table 3; thus, a nickel-based high-temperature alloy component with a Pt electrochemical leveling deposition layer on the surface is obtained.

[0069] (5) The nickel-based superalloy component with Pt electrochemical leveling deposition layer on the surface was placed in a mixed atmosphere of hydrogen and argon (the hydrogen content in the mixed atmosphere was 5% by volume and the balance was argon) for diffusion annealing. The diffusion annealing temperature was 1050℃ and the diffusion annealing time was 8h. After diffusion annealing, the sample was completely embedded in aluminizing powder (the composition of the aluminizing powder included 10% Al, 2% NH4Cl and 88% Al2O3 by mass percentage). The temperature was raised to 1050℃ under argon atmosphere and held for 8h. A Pt modified aluminide coating with curvature adaptation and continuous gradient thickening was obtained on the surface of the nickel-based superalloy.

[0070] After the directionally solidified nickel-based superalloy with a Pt-modified aluminide coating on its surface was oxidized in air at 1000°C for 200 h, a continuous Al2O3-type protective thermally grown oxide layer was formed in the high curvature region, and no continuous cracks were observed penetrating the Pt-modified aluminide layer.

[0071] As can be seen from the oxidation kinetics curve, the Pt-modified aluminide coating in this embodiment exhibits stable weight gain under long-term high-temperature oxidation, demonstrating excellent oxidation resistance.

[0072] The Pt-modified aluminide coating prepared in this embodiment was subjected to XRD testing. The results showed that the coating mainly contained PtAl2 phase and NiAl phase, indicating that the process of this embodiment can successfully prepare the Pt-modified aluminide coating.

[0073] Depend on Figure 4 From (c~d), it can be concluded that the Pt-modified aluminide coating obtained in Example 2, after oxidation in air at 1000℃ for 200 hours, maintains good cross-sectional continuity in both the low-curvature region and the high-curvature end. The interface between the outer layer of the coating, the interdiffusion zone, and the substrate is relatively intact. No continuous cracks penetrating the Pt-modified aluminide layer were observed at the high-curvature end, and the overall protective oxide layer was retained continuously. Simultaneously, the coating thickness at the high-curvature end further increases relative to the low-curvature region, demonstrating a gradient thickening effect with increasing local curvature. This result indicates that, under moderate Pt pre-deposition thickness and pulsed reverse electroplating parameters, the method can balance the thickening control in the low-curvature region with the post-oxidation cross-sectional integrity at the high-curvature end.

[0074] Example 3 A method for preparing a Pt-modified aluminide coating on a nickel-based superalloy with complex curvature, specifically including the following steps: (1) Single-crystal nickel-based superalloy was used as the raw material for nickel-based superalloy components. It was processed into blade-shaped complex curvature specimens. The specimens had a low curvature region, a small radius transition region, and an extremely high curvature region at the tip. The specimen cross-sectional profile data was obtained in the same way as in Example 1. A curvature mapping table was established, including arc length coordinates s, cross-sectional coordinates x, cross-sectional coordinates y, local curvature κ, and curvature partition Bin. All 1600 sampling points along the arc length were substituted into the target thickness function of the Pt pre-deposited layer for calculation. The local curvature was calculated by the following formula: Based on the κ value of all sampling points, the sample surface is divided into four curvature zones.

[0075] (2) The cumulative magnetron sputtering time for the four curvature zones is calculated using the same method as in Example 1. In this example, d min =4.0μm, d max =10.0μm, κ0=5.0mm -1 n=2.0, η s =0.20. Substituting each of the 1600 sampling points in the curvature mapping table into the above formula, and taking the 90th percentile value according to Bin, the calculation results are shown in Table 4.

[0076] Table 4 (3) The sample was placed in an alkaline degreasing solution for degreasing treatment. The alkaline degreasing solution contained 30 g / L NaOH, 30 g / L Na2CO3, and 5.0 g / L OP-10 emulsifier. The solvent was water. The degreasing temperature was 70°C and the treatment time was 30 min. After degreasing, the sample was washed with deionized water and then acid-washed and activated with an acid-washing activation solution (the acid-washing activation solution was prepared by mixing concentrated sulfuric acid, hydrofluoric acid, and deionized water in a volume ratio of 10:1:89). The acid-washing activation time was 5 min. After acid washing, the sample was washed with deionized water and dried at 80°C for 30 min. For the tip area or high curvature area The region was activated by pulsed laser micro-area treatment with a pulsed laser power of 100W, a scanning speed of 300mm / s, a pulse frequency of 45kHz, 5 scans, and a scanning interval of 200μm. Subsequently, stepwise shielded magnetron sputtering was used to form the initial Pt deposition distribution. Pt target material was used for magnetron sputtering, and argon was used as the working gas. According to the cumulative magnetron sputtering time calculated in Table 4, Bin1, Bin2, Bin3, and Bin4 were sputtered for 60s, 180s, 450s, and 600s, respectively, so that the initial Pt deposition amount increased with the increase of local curvature, forming a Pt initial deposition layer with curvature adaptation on the surface of the pretreated sample.

[0077] (4) The sample with the initial Pt deposition layer with the curvature adapted was used as the cathode, and Pt deposition was continued using a Pt electroplating solution with a hexahydroxyplatinate system; the effective Pt concentration was 20 g / L, the pH was 7.0, the electroplating temperature was 80 °C, and the Pt electroplating adopted a tip-adapted multi-stage pulse reverse process, with the forward pulse current density of 0.5 A / dm during the low-current nucleation stage. 2 The positive pulse width was 100 ms, the duty cycle was 40%, and the processing time was 10 min; the positive pulse current density during the stable deposition stage was 1.5 A / dm³. 2 The forward pulse width was 300 ms, the duty cycle was 70%, and the deposition time was 120 min; the reverse pulse current density during the reverse leveling stage was 1.5 A / dm³. 2 The reverse pulse width is 50ms; the pause time during the open-circuit diffusion recovery phase is 500ms. During the reverse leveling phase, one reverse leveling pulse is applied after every m forward pulses; the reverse leveling cycle charge ratio is calculated using the following formula: , change i r =1.5A / dm 2 t r =50ms, i f =1.5A / dm 2 t f Substituting 50ms and m=5 into the above formula, we get Q. r / Q f =0.20, the electroplating stage is used to supplement the Pt deposition amount outside the magnetron sputtering stage, so that the total Pt deposition thickness of each curvature zone is close to the target thickness calculated from the complete curvature table in Table 4; thus, a nickel-based high-temperature alloy component with a Pt electrochemical leveling deposition layer on the surface is obtained.

[0078] (5) The nickel-based superalloy component with Pt electrochemical leveling deposition layer on the surface was placed in a mixed atmosphere of hydrogen and argon (the hydrogen content in the mixed atmosphere was 5% by volume and the balance was argon) for diffusion annealing. The diffusion annealing temperature was 1100℃ and the diffusion annealing time was 10h. After diffusion annealing, the sample was completely embedded in aluminizing powder (the composition of the aluminizing powder included 20% Al, 5% NH4Cl and 75% Al2O3 by mass percentage). The temperature was raised to 1100℃ under argon atmosphere and held for 12h to obtain a Pt modified aluminide coating with curvature adaptation and continuous gradient thickening on the surface of the nickel-based superalloy.

[0079] After oxidizing the obtained single-crystal nickel-based superalloy with Pt-modified aluminide coating in air at 1000℃ for 200h, a continuous Al2O3-type protective thermally grown oxide layer can be formed in the extremely high curvature region, and the coating cross section remains intact.

[0080] As can be seen from the oxidation kinetics curve, the Pt-modified aluminide coating in this embodiment exhibits stable weight gain under long-term high-temperature oxidation, demonstrating excellent oxidation resistance.

[0081] The Pt-modified aluminide coating prepared in this embodiment was subjected to XRD testing. The results showed that the coating mainly contained PtAl2 phase and NiAl phase, indicating that the process of this embodiment can successfully prepare the Pt-modified aluminide coating.

[0082] Depend on Figure 4 From (e~f), it can be concluded that after oxidation in air at 1000℃ for 200 hours, the Pt-modified aluminide coating obtained in Example 3 still maintains good coating cross-sectional integrity in the extremely high curvature region. Because Example 3 uses a higher target Pt deposition thickness and a longer cumulative magnetron sputtering time, a thicker Pt-modified aluminide coating is formed in the extremely high curvature region. The coating can continuously cover the tip surface, and the surface protective oxide layer is still well preserved. No overall peeling or continuous cracks penetrating the Pt-modified aluminide layer were observed; at the same time, the coating body and the substrate maintain continuous bonding. This result indicates that the curvature-adaptive Pt-modified aluminide coating obtained in this example can further enhance the cross-sectional stability and local protection capability of the extremely high curvature region after long-term high-temperature oxidation.

[0083] Comparative Example 1 This comparative example uses the same method as Example 1 to prepare the coating. The only difference is that this comparative example does not use a gradient thickness design and does not set the target Pt deposition thickness for different regions according to the local curvature. Instead, the target thickness of Pt in the low curvature blade region, the medium curvature transition region, and the high curvature blade tip region is the same as the target Pt deposition thickness of Bin1 in Example 1, which is about 3 μm. This makes the entire surface of the sample form a basically uniform Pt deposition layer. The other surface pretreatment, pulsed laser micro-area activation, magnetron sputtering, Pt electroplating, diffusion annealing, and embedding aluminizing treatment conditions are the same as in Example 1.

[0084] After subjecting the comparative sample to 200 hours of high-temperature oxidation in air at 1000℃, it was found that the high-curvature blade tip region of this comparative sample was more prone to local discontinuities in the protective oxide film, coating cross-sectional degradation, or localized peeling. Figure 5 The oxidation kinetics showed that Comparative Example 1 failed earlier than Example 1, indicating that in complex curvature components, a simple uniform thickness Pt modified aluminide coating is insufficient to meet the higher local protection requirements of the high curvature region at the tip, while a gradient thickness coating is more conducive to improving the service stability of the tip region.

[0085] Comparative Example 2 This comparative example uses the same method as Example 1 for coating preparation, the only difference being that conventional constant current DC electroplating is used in the Pt electroplating stage. The sample with a surface curvature adapted to the initial Pt deposition layer is used as the cathode, and Pt deposition continues using a dinitrosodiammineplatinum system Pt electroplating solution. The effective Pt concentration in the Pt electroplating solution is 5 g / L, the pH is 4.0, the electroplating temperature is 30°C, and the DC electroplating current density is 0.5 A / dm³. 2 The electroplating time is 30 minutes, and the low current nucleation stage, reverse leveling stage and open-circuit diffusion recovery stage are not set.

[0086] Depend on Figure 6 It can be concluded that, compared with Example 1, this comparative example shows more obvious local protrusions and thickness fluctuations, and the transition of the Pt deposited layer between adjacent curvature regions is more uneven.

[0087] Comparative Example 3 This comparative example uses the same method as Example 1 for coating preparation, the only difference being that this comparative example does not use stepwise shielded magnetron sputtering to form a curvature-adaptive initial Pt deposition layer, but instead directly uses multi-stage pulsed reverse Pt electroplating for Pt deposition after surface pretreatment. The remaining diffusion annealing and embedding aluminizing conditions are the same as in Example 1.

[0088] Depend on Figure 7 It can be concluded that, compared with Example 1, the controllability of the initial distribution of Pt in the high curvature region is reduced, the uniformity of thickness transition between adjacent curvature regions is reduced, and the final thickness gradient of the aluminide layer is not as obvious as in Example 1.

[0089] This invention addresses the problem of high-temperature oxidation failure in the tip or high-curvature regions of complex-curvature nickel-based superalloy components. It establishes a correlation between local curvature and Pt deposition amount, and achieves controlled continuous thickening of the Pt deposition layer through stepwise magnetron sputtering and multi-stage pulsed reverse Pt electroplating. After diffusion annealing and embedding aluminizing treatment, the resulting Pt-modified aluminide coating exhibits higher local protection reserves in the tip or high-curvature regions, which is beneficial for the formation and retention of a continuous Al2O3-type protective thermally grown oxide layer. This is suitable for surface protection of complex-curvature nickel-based superalloy components used in aero-engines, gas turbines, and other high-temperature applications.

[0090] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing a curvature-adaptive, continuously gradient-thickened Pt-modified aluminide coating, characterized in that, Specifically, the following steps are included: (1) Calculate the local curvature of the surface of the nickel-based superalloy component using the three-dimensional morphology data or cross-sectional profile data of the nickel-based superalloy component with a complex curvature surface; (2) Establish the target thickness function of Pt pre-deposited layer based on the local curvature of the surface of nickel-based superalloy components, and determine the initial deposition thickness of Pt and the cumulative magnetron sputtering time in different local curvature regions; (3) The surface of the nickel-based superalloy component is pretreated, and then a Pt initial deposition layer with curvature matching is formed on the surface of the pretreated nickel-based superalloy component by step-by-step shielded magnetron sputtering. (4) Multi-stage pulse reverse Pt electroplating is used to supplement the initial Pt deposition layer to obtain a nickel-based high-temperature alloy component with a Pt electrochemically leveled deposition layer on the surface. (5) Diffusion annealing and embedding aluminizing treatment are performed on nickel-based superalloy components with Pt electrochemical leveling deposition layers on the surface to obtain a Pt modified aluminide coating with curvature-adapted continuous gradient thickening on the surface of the nickel-based superalloy.

2. The method for preparing the curvature-adapted continuous gradient thickening Pt-modified aluminide coating according to claim 1, characterized in that, The formula for calculating the local curvature of the nickel-based superalloy component surface in step (1) is as follows: Where x is the abscissa function of the component surface profile, in mm; y is the ordinate function of the component surface profile, in mm; and κ is the local curvature, in mm. -1 x′ and y′ are the first derivatives of x and y, respectively, and are dimensionless. x″ and y″ are the second derivatives of x and y, respectively, and are in mm. -1 .

3. The method for preparing the curvature-adapted continuous gradient thickening Pt-modified aluminide coating according to claim 1, characterized in that, The target thickness function of the Pt pre-deposited layer in step (2) is: , where d * Pt (κ) represents the target deposition thickness at the local curvature κ, in μm, d min The lower limit of the target thickness for Pt pre-deposition in low curvature regions, in μm, d max κ0 represents the upper limit of the target thickness for Pt pre-deposition in the extremely high curvature region, in μm, and κ0 is the curvature adjustment parameter, in mm. -1 , where n is the dimensionless curvature sensitivity index.

4. The method for preparing the curvature-adaptive continuous gradient thickening Pt-modified aluminide coating according to claim 3, characterized in that, The d min 2~4μm, d max The value is 6~10μm, and the value of κ0 is 0.5~5mm. -1 The value of n is 0.5 to 2.

0.

5. The method for preparing a curvature-adaptive, continuously gradient-thickened Pt-modified aluminide coating according to claim 1, characterized in that, The formula for determining the cumulative magnetron sputtering time in step (2) is as follows: , where t s (κ) represents the cumulative magnetron sputtering time at the local curvature κ, in seconds (s) and d. * Pt (κ) represents the target deposition thickness at the local curvature κ, in μm, v s η represents the magnetron sputtering deposition rate, expressed in μm / s. s The initial deposition proportion undertaken during the magnetron sputtering stage is a dimensionless proportionality coefficient, ranging from 0.02 to 0.

20.

6. The method for preparing the curvature-adaptive continuous gradient thickening Pt-modified aluminide coating according to claim 1, characterized in that, Step (4) employs a tip-adapted multi-stage pulsed reverse Pt electroplating process for supplementary deposition; the tip-adapted multi-stage pulsed reverse Pt electroplating process sequentially includes a low-current nucleation stage, a stable deposition stage, a reverse leveling stage, and an open-circuit diffusion recovery stage, wherein the forward pulse current density of the low-current nucleation stage is 0.1~0.5 A / dm². 2 The positive pulse width is 10~100ms, the duty cycle is 10~40%, the processing time is 1~10min, and the positive pulse current density during the stable deposition stage is 0.5~1.5A / dm³. 2 The forward pulse width is 50~300ms, the duty cycle is 30~70%, the deposition time is 10~120min, and the reverse pulse current density in the reverse leveling stage is 0.05~1.5A / dm². 2 The reverse pulse width is 1~50ms, and the pause time of the open-circuit diffusion recovery phase is 10~500ms.

7. The method for preparing the curvature-adaptive continuous gradient thickening Pt-modified aluminide coating according to claim 6, characterized in that, In the reverse leveling stage, one reverse leveling pulse is applied after every m forward pulses, where m is 5~20; the reverse leveling cycle charge ratio Q r / Q f It ranges from 0.02 to 0.25, where: In the formula, i r This is the absolute value of the reverse pulse current density, in A / dm². 2 , t r i is the reverse pulse width, in milliseconds (ms). f This represents the absolute value of the forward pulse current density during the reverse leveling stage, expressed in A / dm². 2 , t f Q represents the positive pulse width in milliseconds (ms), where m is the number of positive pulses between two adjacent negative leveling pulses. r / Q f It is a dimensionless parameter.

8. The method for preparing the curvature-adaptive continuous gradient thickening Pt-modified aluminide coating according to claim 1, characterized in that, The conditions for the diffusion annealing process in step (5) are as follows: it is carried out in a protective atmosphere, the diffusion annealing temperature is 900~1100℃, and the diffusion annealing time is 2~10h.

9. The method for preparing the curvature-adaptive continuous gradient thickening Pt-modified aluminide coating according to claim 1, characterized in that, In step (5), an aluminizing agent is used for embedding and aluminizing treatment. The composition of the aluminizing agent, by mass percentage, includes: 5-20% Al powder, 1-5% NH4Cl, and the balance is Al2O3. The conditions for embedding and aluminizing treatment are: under an inert atmosphere, the temperature is kept at 950-1100℃ for 4-12 hours.

10. The curvature-adaptive continuous gradient thickening Pt-modified aluminide coating prepared by the method of any one of claims 1 to 9.

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