Active element zr modified beta-(ni,pt)al coating and process for producing the same

Abstract

The present disclosure provides a kind of active element Zr modified β-(Ni,Pt) Al coating and its preparation process, belong to high-temperature alloy surface high-temperature protection coating technical field.Preparation process includes: the electrochemical degreasing and activation treatment of Ni-based high-temperature alloy sample;The first electroplating treatment is carried out to the Ni-based high-temperature alloy sample after processing, to deposit Pt layer on the surface of the Ni-based high-temperature alloy sample, form the sample containing plated Pt layer;The vacuum diffusion annealing treatment is carried out to the sample containing plated Pt layer, form the sample containing Pt diffusion annealing layer;The second electroplating treatment is carried out to the sample containing Pt diffusion annealing layer, deposit Ni-Zr layer on the surface of the sample, form the sample containing Ni-Zr layer;The sample containing Ni-Zr layer is carried out gas phase aluminizing, obtain active element Zr modified β-(Ni,Pt) Al coating.The present disclosure introduces Ni-Zr layer by electroplating method, can accurately control the content of active element Zr in Zr modified β-(Ni,Pt) Al coating, while reducing the thickness of mutual diffusion zone and the number of TCP phase therein.

Description

Technical Field

[0001] This disclosure belongs to the field of high-temperature protective coating technology for high-temperature alloy surfaces, specifically relating to a Zr-modified β-(Ni,Pt)Al coating and its preparation process. Background Technology

[0002] Currently, the inlet temperature of advanced gas turbines can reach 1600℃, while turbine blades typically operate for extended periods in high-temperature environments of 1000℃ to 1200℃. Ni-based superalloys, due to their excellent high-temperature mechanical properties, are widely used as structural materials for hot-end components such as turbine blades and rotor blades. However, during high-temperature service, blades are susceptible to oxidation and hot corrosion, affecting their service life and reliability. To protect the superalloy substrate, existing technologies typically coat the surface of hot-end components with thermal barrier coatings (TBCs). TBCs mainly consist of a ceramic layer and a metal bonding layer. The ceramic layer provides thermal insulation, reducing the substrate surface temperature by 100℃ to 300℃; the metal bonding layer alleviates stress caused by the difference in thermal expansion coefficients between the ceramic layer and the substrate, while also preventing high-temperature oxidation and hot corrosion of the substrate alloy. β-(Ni,Pt)Al coatings, due to their excellent high-temperature oxidation and hot corrosion resistance, have become the preferred material for the metal bonding layer of TBCs.

[0003] Existing β-(Ni,Pt)Al coatings are typically prepared using Pt electroplating, vacuum diffusion annealing, and vapor-phase aluminizing. To further improve coating performance, some techniques introduce the active element Zr to modify the coating. However, when preparing Zr-modified β-(Ni,Pt)Al coatings using vapor-phase co-diffusion, the Zr content is difficult to control precisely due to the significant activity difference between Zr and Al. Studies have found that excessively high Zr content in the coating can actually reduce its oxidation and hot corrosion resistance. Furthermore, during vapor-phase aluminizing, the outer layer of the coating is mainly formed by the outward diffusion of Ni from the base alloy, leading to an increase in the thickness of the interdiffusion zone. Simultaneously, refractory elements precipitate to form the TCP phase, further reducing the high-temperature mechanical properties of the base alloy.

[0004] Therefore, existing technologies have the following problems: on the one hand, it is difficult to accurately control the content of the active element Zr in the coating; on the other hand, the excessive thickness of the interdiffusion zone and the large number of TCP phases limit further improvement of the coating performance. Therefore, developing a novel β-(Ni,Pt)Al coating preparation method that can precisely control the content of active elements, reduce the thickness of the interdiffusion zone, and decrease the formation of the TCP phase has become an urgent technical problem to be solved. Summary of the Invention

[0005] This disclosure aims to at least solve one of the technical problems existing in the prior art, and to provide a Zr-modified β-(Ni,Pt)Al coating and its preparation process.

[0006] One aspect of this disclosure provides a process for preparing a Zr-modified β-(Ni,Pt)Al coating, the process comprising: Electrochemical degreasing and activation treatment was performed on Ni-based superalloy samples. The Ni-based superalloy sample was subjected to a first electroplating treatment to deposit a Pt layer on the surface of the Ni-based superalloy sample, forming a sample with a Pt layer. Vacuum diffusion annealing was performed on the sample containing the Pt layer to form a sample containing the Pt diffusion annealed layer. The Pt diffusion annealed layer sample was subjected to a second electroplating treatment to deposit a Ni-Zr layer on the sample surface, forming a Ni-Zr layer sample. Vapor-phase aluminizing was performed on the Ni-Zr layer sample to obtain a Zr-modified β-(Ni,Pt)Al coating.

[0007] Optionally, the Ni-based superalloy sample is subjected to electrochemical degreasing, including: In a 5–15 g / L NaOH solution, a Ni-based superalloy sample was used as the cathode, and a nickel plate as the anode. The cathode current density was 2–12 A / dm³. 2 The processing time is 1 to 5 minutes.

[0008] Optionally, the Ni-based superalloy sample is activated, including: Using a 15%~40% hydrochloric acid solution as the activation solution, the Ni-based superalloy sample was immersed in the activation solution for 1~5 minutes at room temperature.

[0009] Optionally, in the first electroplating process, the electroplating solution includes: dinitrosodiammineplatinum, aminosulfonic acid, sodium dodecyl sulfate, and deionized water; The pH of the electroplating solution is 1-5; The electroplating temperature is 60~95℃, and the current density is 0.5~4A / dm³. 2 The electroplating time is 30~90min, and the thickness of the electroplated Pt layer is 2~7μm.

[0010] Optionally, the concentration of the dinitrosodiammineplatinum is 5~20 g / L; The concentration of the aminosulfonic acid is 25~60 g / L; The concentration of sodium dodecyl sulfate is 0.05~0.15 g / L.

[0011] Optionally, the sample containing the Pt-plated layer undergoes diffusion annealing treatment, including: Stress-relief annealing was performed at a heating rate of 5~10℃ / min and held at 400~700℃ for 2~4h. Then, the temperature was raised to 1000~1100℃ and held for 2~4h for Pt diffusion treatment.

[0012] Optionally, in the second electroplating process, the electroplating solution includes citric acid, nickel sulfate hexahydrate, and deionized water; The Zr content is 10~40g / L; The pH value of the electroplating solution is 8~11; The electroplating temperature is 30~60℃, and the current density is 2~10A / dm². 2 The electroplating time is 10~40min, and the thickness of the electroplated Ni-Zr layer is 5~30μm.

[0013] Optionally, the concentration of the citric acid is 0.15~0.5 mol / L; The concentration of nickel sulfate hexahydrate is 0.15~0.5 mol / L.

[0014] Optionally, the vapor-phase aluminizing of the Ni-Zr layer sample includes: The sample containing the Ni-Zr layer was suspended above a mixture of activator, aluminizing agent and inert agent without contacting the mixture, and heated to 950~1100℃ under vacuum conditions and held for 4~6 hours.

[0015] In another aspect of this disclosure, a Zr-modified β-(Ni,Pt)Al coating is provided, wherein the Zr-modified β-(Ni,Pt)Al coating is prepared using the preparation process described above.

[0016] This disclosure discloses a Zr-modified β-(Ni,Pt)Al coating and its preparation process. The preparation process includes: electrochemical degreasing and activation treatment of a Ni-based superalloy sample; a first electroplating treatment of the treated Ni-based superalloy sample to deposit a Pt layer on the surface of the Ni-based superalloy sample, forming a Pt-plated sample; diffusion annealing treatment of the Pt-plated sample to form a Pt-diffusion-annealed sample; a second electroplating treatment of the Pt-diffusion-annealed sample to deposit a Ni-Zr layer on the sample surface, forming a Ni-Zr-based sample; and vapor-phase aluminizing of the Ni-Zr-based sample to obtain a Zr-modified β-(Ni,Pt)Al coating. This disclosure introduces a Ni-Zr layer through electroplating, which can precisely control the content of the active element Zr in the Zr-modified β-(Ni,Pt)Al coating, while reducing the thickness of the interdiffusion region and the amount of TCP phase therein. Attached Figure Description

[0017] Figure 1This is a flowchart illustrating the preparation process of the Zr-modified β-(Ni,Pt)Al coating according to a specific embodiment of this disclosure. Figure 2 The cross-sectional morphology of the electroplated Ni-Zr layer in Embodiment 1 of this disclosure is shown. Figure 3 The cross-sectional morphology of the aluminized coating in Embodiment 1 of this disclosure is shown. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.

[0019] As shown in Figure 1, one aspect of this disclosure provides a preparation process S100 for a Zr-modified β-(Ni,Pt)Al coating, specifically including the following steps S110~S150: S110. Electrochemical degreasing and activation treatment was performed on the Ni-based high-temperature alloy sample.

[0020] It should be noted that pretreatment of the sample should precede step S110, such as grinding, sandblasting, and ultrasonic cleaning. In some embodiments, the Ni-based superalloy sample is ground with 800# SiC sandpaper, followed by wet sandblasting with 200-mesh abrasive particles, and finally ultrasonically treated with deionized water, acetone, and alcohol for 5 minutes in sequence to remove residual abrasive particles and oil stains from the sample surface. The purpose of this pretreatment is to remove the oxide layer on the surface of the Ni-based superalloy sample substrate and improve the surface activity of the substrate, thereby improving the adhesion between the electroplated layer and the substrate.

[0021] Further, in step S110, the electrochemical degreasing of the Ni-based superalloy sample specifically includes: Oil removal was performed in a 5-15 g / L NaOH solution, with the sample as the cathode and a nickel plate as the anode. The cathode current density was 2-12 A / dm³. 2 The processing time is 1-5 minutes; Furthermore, the activation treatment of the Ni-based superalloy sample specifically includes: the activation solution is a hydrochloric acid solution with a volume fraction of 15% to 40%, and during the activation treatment, the sample is immersed in the activation solution for 1 to 5 minutes at room temperature.

[0022] S120. The treated Ni-based superalloy sample is subjected to a first electroplating treatment to deposit a Pt layer on the surface of the Ni-based superalloy sample, forming a sample with a Pt plating layer.

[0023] In step S120 above, the electroplating pure Pt layer solution consists of 5-20 g / L dinitrosodiammonium platinum, 25-60 g / L aminosulfonic acid, 0.05-0.15 g / L sodium dodecyl sulfate, and the remainder is deionized water. The pH of the solution is adjusted to 1-5; the plating bath temperature is set to 60-95℃; and the current density is 0.5-4 A / dm³. 2 The electroplating time is 30~90min, and the thickness of the electroplated Pt layer is 2~7μm.

[0024] S130. The sample containing the Pt layer is subjected to diffusion annealing treatment to form a sample containing the Pt diffusion annealed layer.

[0025] In step S130 above, the specific process of vacuum diffusion annealing is to use a heating rate of 5~10℃ / min, hold at 400~700℃ for 2~4h for stress relief annealing, and then heat to 1000~1100℃ and hold for 2~4h for Pt diffusion treatment to achieve the purpose of diluting the Pt content on the surface.

[0026] S140. The Pt diffusion annealed layer sample is subjected to a second electroplating treatment to deposit a Ni-Zr layer on the sample surface, forming a Ni-Zr layer sample.

[0027] In step S140 above, the electroplating solution used is: citric acid 0.15~0.5 mol / L, nickel sulfate hexahydrate 0.15~0.5 mol / L, and the remainder is deionized water; the Zr powder content is 10~40 g / L; the pH of the electroplating solution is adjusted to 8~11 with ammonia; the composite electroplating process parameters are: temperature 30~60℃, current density 2~10 A / dm³. 2 The electroplating time is 10~40min, and the thickness of the electroplated Ni-Zr layer is 5~30μm.

[0028] It should be noted that in this embodiment, a Pt layer is first deposited on the substrate, and a Ni-Zr layer is then deposited after the Pt layer is completed. During the formation of the Ni-Zr layer, an additional Ni layer is added. On the one hand, the thickness of the electroplated Ni layer is much greater than that of the Pt layer, meaning that the range of Zr content is wider. On the other hand, the addition of the Ni layer affects the coating formation process. Most of the Ni in the coating comes from the Ni layer rather than the high-temperature alloy substrate, thus reducing the thickness of the interdiffusion region formed by Ni diffusion and the amount of its TCP phase.

[0029] S150. Aluminizing the Ni-Zr layer sample in the vapor phase was performed to obtain a Zr-modified β-(Ni,Pt)Al coating.

[0030] In step S150 above, the vapor-phase aluminizing process is as follows: the sample is suspended above a mixture of activator, aluminizing agent, and inert agent, ensuring that the sample does not come into contact with the mixture. The activator is ammonium chloride, the aluminizing agent is iron-aluminum powder, and the inert agent is alumina powder. The inert agent comprises 0-50 wt.%, the activator comprises 1-5 wt.%, and the remainder is aluminizing agent. The aluminizing temperature is between 950 and 1100°C, and the holding time is between 4 and 6 hours.

[0031] This disclosure describes a composite electroplating technique to deposit a Ni-Zr layer, introducing the active element Zr into the β-(Ni,Pt)Al coating. The preparation process is stable, and the content and distribution of the active element Zr in the coating can be precisely controlled and adjusted, with low preparation cost.

[0032] In another aspect of this disclosure, a Zr-modified β-(Ni,Pt)Al coating is provided, which is prepared using the preparation process described above. For details of the preparation process, please refer to the above description, which will not be repeated here.

[0033] The preparation process of Zr-modified β-(Ni,Pt)Al coating will be further explained below with reference to specific embodiments: Example 1 S1. In this embodiment, a nickel-based single-crystal superalloy with the composition (7.0Cr, 7.5Co, 1.5Mo, 5.0W, 6.2Ta, 6.2Al, 3.0Re, 0.15Hf, 0.05C, 0.05B, 0.01Y, 69.54Ni) was selected as the matrix material. The superalloy was cut into cylindrical specimens of φ15×1.5mm using wire electrical discharge machining (EDM), and a 1.5mm diameter hole was cut 1.5mm from the edge of the specimen to facilitate suspension of the specimen for coating deposition. S2. Surface treatment of the sample: The sample was ground from 150# sandpaper to 800# sandpaper using a grinding machine, and the edges and corners of the sample were chamfered. Then, the substrate sample was sandblasted with 1-2 atm pressure and 200-mesh corundum abrasive. Finally, the sample was ultrasonically cleaned for 10 minutes in sequence with deionized water, acetone, and alcohol to remove residual sandblasting particles and oil stains from the surface.

[0034] S3. Pre-treatment, which includes electrochemical degreasing and activation. The electrochemical degreasing process involves immersing the sample in a 15 g / L sodium hydroxide solution. The positive terminal of the power supply is connected to a stainless steel anode, and the negative terminal is connected to the sample as the cathode. The current density is 5 A / dm³. 2 Perform a 3-minute degreasing treatment. Activation treatment process: Immerse the sample in a 30% (v / v) activation solution for 4 minutes.

[0035] S4. Electroplating a pure Pt layer. The Pt electroplating solution consisted of 8 g / L dinitrosodiammineplatinum, 45 g / L aminosulfonic acid, 0.1 g / L sodium dodecyl sulfate, and deionized water. The electroplating parameters were 80℃, solution pH 3, and an efficiency of 1 A / dm³. 2 A 3 μm Pt layer was deposited on the surface of the pretreated sample using a current density of 10 °C / min. The subsequent annealing process involved heating at 400 °C for 2 h at a heating rate of 10 °C / min, followed by heating to 1020 °C at the same heating rate and holding for 2 h before furnace cooling.

[0036] S5. Electroplating Ni-Zr layer. The Ni-Zr plating solution consists of 0.35 mol / L citric acid, 0.4 mol / L nickel sulfate hexahydrate, and the remainder deionized water. The added Zr powder content is 25 g / L. The pH of the plating solution is adjusted to 10 with ammonia. The composite electroplating process parameters are: temperature 35℃, current density 8 A / dm³. 2 A 13 μm Ni-Zr layer was deposited on the surface of the Pt-plated annealed layer. The cross-sectional morphology of the electroplated Ni-Zr layer is as follows. Figure 2 As shown.

[0037] S6. Vapor-phase aluminizing. Iron-aluminum powder is used as the aluminizing agent, alumina powder as the inert agent, and ammonium chloride as the catalyst. The weight ratio of iron-aluminum powder to alumina powder is 1:1, and the ammonium chloride content is 2% of the total weight. The mixture is heated to 1050℃ under vacuum and held for 5 hours.

[0038] Figure 2 The figure shows the cross-sectional morphology of the composite electroplated Ni-Zr layer. As can be seen from the figure, the thickness of the electroplated layer is about 13 μm, and fine Zr particles are dispersed in the Ni-Zr layer. Figure 3 The figure shows the cross-sectional morphology of the Zr-modified β-(Ni,Pt)Al coating after vapor-phase aluminizing. As can be seen from the figure, the overall coating thickness is approximately 40 μm, and the thickness ratio of the outer layer to the interdiffusion zone is approximately 2:1. In contrast, the thickness ratio of the outer layer to the interdiffusion zone in conventional β-(Ni,Pt)Al coatings is typically 1:1. Therefore, the method in this embodiment significantly reduces the thickness of the interdiffusion zone and the amount of TCP phase. Furthermore, during vapor-phase aluminizing, due to the low Zr content, Zr particles gradually dissolve into the β phase of the outer layer during coating formation.

[0039] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A preparation process for a Zr-modified β-(Ni,Pt)Al coating, characterized in that, The preparation process includes: Electrochemical degreasing and activation treatment was performed on Ni-based superalloy samples. The Ni-based superalloy sample was subjected to a first electroplating treatment to deposit a Pt layer on the surface of the Ni-based superalloy sample, forming a sample with a Pt layer. Vacuum diffusion annealing was performed on the sample containing the Pt layer to form a sample containing the Pt diffusion annealed layer. The Pt diffusion annealed layer sample was subjected to a second electroplating treatment to deposit a Ni-Zr layer on the sample surface, forming a Ni-Zr layer sample. Vapor-phase aluminizing was performed on the Ni-Zr layer sample to obtain a Zr-modified β-(Ni,Pt)Al coating.

2. The preparation process according to claim 1, characterized in that, Electrochemical degreasing of Ni-based superalloy samples included: In a NaOH solution with a concentration of 5–15 g / L, using a Ni-based superalloy sample as the cathode and a nickel plate as the anode, the cathode current density was 2–12 A / dm³. 2 The processing time is 1 to 5 minutes.

3. The preparation process according to claim 1, characterized in that, Activation treatment of Ni-based superalloy samples includes: Using a 15%~40% hydrochloric acid solution as the activation solution, the Ni-based superalloy sample was immersed in the activation solution for 1~5 minutes at room temperature.

4. The preparation process according to claim 1, characterized in that, In the first electroplating process, the electroplating solution includes: dinitrosodiaminoplatinum, aminosulfonic acid, sodium dodecyl sulfate and deionized water; The pH of the electroplating solution is 1-5; The electroplating temperature is 60~95℃, and the current density is 0.5~4A / dm³. 2 The electroplating time is 30~90min, and the thickness of the electroplated Pt layer is 2~7μm.

5. The preparation process according to claim 4, characterized in that, The concentration of the dinitrosodiamineplatinum is 5~20 g / L; The concentration of the aminosulfonic acid is 25~60 g / L; The concentration of sodium dodecyl sulfate is 0.05~0.15 g / L.

6. The preparation process according to claim 1, characterized in that, The sample containing the Pt-plated layer underwent diffusion annealing treatment, including: Stress-relief annealing was performed at a heating rate of 5~10℃ / min and held at 400~700℃ for 2~4h, followed by Pt diffusion treatment at 1000~1100℃ for 2~4h.

7. The preparation process according to claim 1, characterized in that, In the second electroplating process, the electroplating solution includes citric acid, nickel sulfate hexahydrate, and deionized water; The Zr content is 10~40g / L; The pH value of the electroplating solution is 8~11; The electroplating temperature is 30~60℃, and the current density is 2~10A / dm². 2 The electroplating time is 10~40min, and the thickness of the electroplated Ni-Zr layer is 5~30μm.

8. The preparation process according to claim 7, characterized in that, The concentration of citric acid is 0.15~0.5 mol / L; The concentration of nickel sulfate hexahydrate is 0.15~0.5 mol / L.

9. The preparation process according to claim 1, characterized in that, The vapor-phase aluminizing of the Ni-Zr layer sample includes: The sample containing the Ni-Zr layer was suspended above a mixture of activator, aluminizing agent and inert agent without contacting the mixture, and heated to 950~1100℃ under vacuum conditions and held for 4~6 hours.

10. A Zr-modified β-(Ni,Pt)Al coating, characterized in that, The Zr-modified β-(Ni,Pt)Al coating is prepared using the preparation process described in any one of claims 1 to 9.

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