Low-diffusion Pt-MxOy coating for high-temperature alloy protection and preparation method of low-diffusion Pt-MxOy coating

Abstract

The invention relates to the technical field of high-temperature protective coatings, and particularly discloses a low-diffusion Pt-MxOy coating for high-temperature alloy protection and a preparation method of the low-diffusion Pt-MxOy coating. The preparation method of the low-diffusion Pt-MxOy coating for high-temperature alloy protection comprises the following steps that a base body is pretreated, and the pretreated base body is obtained; taking the pretreated matrix as a cathode, and putting the matrix into the composite plating solution for electroplating; and the electroplated sample is subjected to vacuum annealing, and after annealing is finished, the low-diffusion Pt-MxOy coating for high-temperature alloy protection is obtained. The composite plating solution is a platinum plating solution containing MxOy particles. According to the low-diffusion Pt-MxOy coating for high-temperature alloy protection, the phase change process of metastable-state aluminum oxide can be accelerated, and the oxidation rate in the stable oxidation stage can be remarkably reduced; compared with a traditional (Ni, Pt) Al coating, mutual diffusion between a matrix and the coating can be greatly reduced, the mechanical property of the matrix is improved, and the preparation cost of the coating is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of high temperature protective coatings, and in particular to a low diffusion Pt-M for high temperature alloy protection. x O y Coating and method for preparing the same. Background Art

[0002] In the past few decades, the performance requirements of gas turbine engines have continued to increase, mainly due to the rapid development of the aerospace, shipbuilding and power industries. The turbine blades at the front end of the engine, as key hot end components, are also experiencing increasingly high service temperatures. At present, the commonly used material for blades is nickel-based high-temperature alloys, and the operating temperature has reached more than 90% of the absolute melting point. Improved structural design and airfoil cooling technology applied to higher-strength high-temperature alloys, and the use of continuously improved high-temperature alloy protective coating systems for protection, have become key technologies for increasing the service temperature of aircraft engine blades and have been widely used. Among them, platinum-modified aluminide coatings, as metal bonding layers in thermal barrier coatings, have become a necessary choice and important research direction for future high-performance aircraft engines due to their simple process, excellent oxidation resistance and spalling resistance, and effective reduction of element interdiffusion.

[0003] Platinum-modified aluminide coatings, especially (Ni,Pt)Al coatings, are widely used as bonding layers in thermal barrier coating systems. They can grow a thermally grown oxide film with a thickness of 1 to 10 μm on the surface to protect the base metal and coating to meet the high temperature requirements of turbine engine components. The preparation of (Ni,Pt)Al coatings includes three steps: electroplating Pt, vacuum annealing, and diffusion aluminization. Researchers generally find that the external active atmosphere during aluminization (such as AlCl x ) reacts with Ni atoms in the matrix, consumes a large number of Ni atoms, and causes a phase transition from γ to γ' or even β in the matrix, destroying the γ / γ' coherent structure and forming an interdiffusion zone (IDZ) in the matrix. More seriously, the phase transition causes the refractory elements originally dissolved in γ to precipitate as a topologically close-packed phase (TCP) and form a secondary reaction zone (SRZ), which significantly damages the mechanical properties of the matrix. With the extension of service time, the element interdiffusion between the matrix and the coating intensifies, the IDZ and SRZ thicken, and the mechanical properties of the matrix further decrease. The applicant's preliminary research results found that after preparing (Ni, Pt) Al coating on the first generation of nickel-based single crystal high-temperature alloy, the endurance life, elongation and cross-sectional shrinkage of the single crystal substrate were reduced by 21.03%, 10.81% and 23.45%, respectively. In addition, when elements such as Ti, Ta, and W in the alloy diffuse into the coating or oxide film, the protective performance of the oxide film is severely damaged. Therefore, it is crucial to reduce the interdiffusion between the coating and the substrate while ensuring the excellent antioxidant performance of the coating.

[0004] On the other hand, the oxidation resistance of the coating is related to the formation rate of a stable oxide film. There are various types and crystal structures of Al2O3, but α-Al2O3 is generally considered to be the most ideal oxide film structure. In α-Al2O3, the diffusion rate of the O element is very low. Therefore, once the α-Al2O3 film is formed, the oxidation rate of the coating system is significantly reduced. At temperatures not exceeding 1200°C, metastable θ or γ-Al2O3 will always be generated first, and will eventually become stable α-Al2O3 after further oxidation. The slow transformation process of metastable alumina usually leads to the formation of alumina and faster degradation of the coating. Therefore, in order to improve the high-temperature oxidation resistance of alumina, this field urgently needs a method that can promote the phase change process of alumina. Summary of the invention

[0005] In order to overcome at least one of the technical problems existing in the prior art, the present invention provides a low diffusion Pt-M for high temperature alloy protection. x O y Coating and method for preparing the same.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention first provides a low diffusion Pt-M for high temperature alloy protection x O y The method for preparing the coating comprises the following steps:

[0008] Pre-treating the substrate to obtain a pre-treated substrate;

[0009] The pretreated substrate is used as a cathode and placed in a composite plating solution for electroplating;

[0010] The electroplated sample is subjected to vacuum annealing, and after the annealing, the low-diffusion Pt-M for high-temperature alloy protection is obtained. x O y coating;

[0011] The composite plating solution contains M x O y Platinum plating solution for particles.

[0012] The inventors surprisingly found in their research that the low diffusion Pt-M x O y In the preparation method of the coating, M is added x O y The particles can produce a significant "template" effect, which can rapidly transform the metastable alumina in the prepared coating into stable α-Al2O3; at the same time, it can also make the prepared coating have a lower oxidation rate.

[0013] Preferably, the x O y The platinum plating solution of the particles is prepared by the following method: M is added to the platinum plating solution. x O y The particles are stirred evenly to obtain the M-containing x O y Platinum plating solution for particles.

[0014] Preferably, it contains M x O y The platinum plating solution of the particles x O y The content of the particles is 10-20 g / L.

[0015] Most preferably, it contains M x O y The platinum plating solution of the particles x O y The content of the particles is 15g / L.

[0016] Preferably, the M x O y The particle size of the particles is 50 to 100 nm.

[0017] Preferably, the M x O y The particles are selected from CeO2 particles and / or ZrO2 particles.

[0018] The inventors surprisingly found in their research that in the preparation method of the present invention, M x O y The specific choice of particles is critical; it is not a random choice. x O y The particles can rapidly transform the metastable alumina in the prepared coating into stable α-Al2O3; studies have shown that only by using CeO2 particles and / or ZrO2 particles can the metastable alumina in the prepared coating be rapidly transformed into stable α-Al2O3; however, using Y2O3 particles cannot rapidly transform the metastable alumina in the prepared coating into stable α-Al2O3.

[0019] The inventors surprisingly found in their research that in the preparation method of the present invention, M x O y The specific choice of particles is critical; it is not a random choice. x O yThe particles can make the prepared coating have a lower oxidation rate; the study shows that the oxidation rate of the coating prepared by using ZrO2 particles is much lower than that without adding M x O y The coating prepared by using the particles is also significantly smaller than the coating prepared by using CeO2 particles or Y2O3 particles.

[0020] Preferably, the platinum plating solution is an aqueous solution containing Pt(NH3)2(NO2)2 and NaNO2.

[0021] Preferably, the content of Pt(NH3)2(NO2)2 in the platinum plating solution is 8 to 15 g / L, and the content of NaNO2 is 8 to 15 g / L.

[0022] Most preferably, the content of Pt(NH3)2(NO2)2 in the platinum plating solution is 10 g / L, and the content of NaNO2 is 10 g / L.

[0023] Preferably, the substrate is a second generation or higher nickel-based single crystal high-temperature alloy substrate.

[0024] Preferably, the specific conditions of the electroplating are: electroplating temperature 75-85°C, current density 4-6 mA / cm 2 , pH=10~12, time is 2.5h~3.5h.

[0025] Preferably, the specific conditions of the vacuum annealing are: annealing temperature is 1000-1100°C, insulation is 0.5-2h, vacuum degree is 10 -3 Pa, the heating rate is less than 5-15℃ / min.

[0026] Most preferably, the specific conditions of the vacuum annealing are: annealing temperature is 1050°C, insulation is 1h, vacuum degree is 10 -3 Pa, the heating rate is less than 10℃ / min.

[0027] The present invention also provides a low diffusion Pt-M prepared by the above preparation method for high temperature alloy protection. x O y coating.

[0028] Beneficial effect: The present invention provides a new low-diffusion Pt-M for high-temperature alloy protection. x O yThe invention discloses a method for preparing a coating. The method comprises adding oxide particles to a platinum plating solution during the electroplating process. On the one hand, the addition of oxide particles can produce a significant "template" effect, thereby accelerating the metastable aluminum oxide phase transition process and reducing the oxide film growth rate. On the other hand, the oxidation rate in the stable oxidation stage can be significantly reduced, thereby slowing down the consumption rate of the Al element inside the coating and extending the service life of the coating. Compared with the traditional (Ni, Pt)Al coating, the low-diffusion Pt-M prepared by the method of the invention for high-temperature alloy protection is x O y Coating, which can greatly improve resistance to high temperature oxidation.

[0029] In addition, the low diffusion Pt-M for high temperature alloy protection described in the present invention x O y The coating preparation method can be achieved by regulating the current density, pulse wave frequency and pulse width during the electroplating process through a programmable pulse power supply. Compared with the traditional (Ni, Pt) Al coating preparation process, it has the advantages of being green and pollution-free, low energy consumption, simple process, high temperature oxidation resistance and reliability. It is of great significance to improve the service life of mechanical moving parts such as ship engines, turbofans and turbines under high temperature oxidation environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Surface morphology of low-diffusion Pt-CeO2, Pt-ZrO2 and Pt-Y2O3 coatings for high-temperature alloy protection prepared by the method in Example 1, Example 2 and Comparative Example 1 of the present invention as prepared.

[0031] Figure 2 These are cross-sectional morphology images of the deposited low-diffusion Pt-CeO2, Pt-ZrO2 and Pt-Y2O3 coatings for high-temperature alloy protection prepared by the methods described in Example 1, Example 2 and Comparative Example 1 of the present invention.

[0032] Figure 3 This is a graph of the constant temperature oxidation weight gain curves at 1100°C of low diffusion Pt-CeO2, Pt-ZrO2 and Pt-Y2O3 coatings for high temperature alloy protection prepared by the methods described in Example 1, Example 2 and Comparative Example 1 of the present invention.

[0033] Figure 4 This is a graph showing the oxidation rate constant results of isothermal oxidation at 1100°C for low-diffusion Pt-CeO2, Pt-ZrO2 and Pt-Y2O3 coatings for high-temperature alloy protection prepared by the methods described in Example 1, Example 2 and Comparative Example 1 of the present invention.

[0034] Figure 5This is a graph showing the oxidation rate constant of the coating prepared in Comparative Example 2 at 1100°C under constant temperature oxidation. DETAILED DESCRIPTION

[0035] The present invention is further explained below in conjunction with specific examples, but the examples do not limit the present invention in any form.

[0036] Example 1 Preparation of low diffusion Pt-CeO2 coating for high temperature alloy protection

[0037] S1. Take the second-generation nickel-based single crystal high-temperature alloy RenéN5 with a size of Φ15×2mm as the substrate; then polish the substrate with 180#, 600#, and 800# SiC sandpaper in turn, and sandblast the sample under a pressure of 0.3MPa. The sandblasted sample is deoiled in a 50g / L boiling sodium hydroxide aqueous solution for 10 minutes, and then ultrasonically cleaned in acetone and alcohol for 10 minutes respectively to obtain the pretreated substrate;

[0038] S2. The pretreated substrate is used as a cathode, and a nickel plate is used as an anode, and is placed in a platinum plating solution containing CeO2 particles for electroplating; the coating thickness is 5 μm;

[0039] S3. The electroplated sample was vacuum annealed at a temperature of 1050°C for 1 h and a vacuum degree of 10 -3 Pa, the heating rate is less than 10°C / min, and after the annealing is completed, the low-diffusion Pt-CeO2 coating for high-temperature alloy protection is obtained.

[0040] The preparation method of the platinum plating solution containing CeO2 particles is as follows: adding CeO2 particles (100nm) into the platinum plating solution, stirring evenly to obtain a platinum plating solution containing 15g / L CeO2 particles; the platinum plating solution is prepared by the following method: adding Pt(NH3)2(NO2)2 and NaNO2 into water, stirring evenly to obtain the platinum plating solution; wherein the contents of Pt(NH3)2(NO2)2 and NaNO2 in the platinum plating solution are: Pt(NH3)2(NO2)2 10g / L, NaNO2 10g / L respectively;

[0041] The specific conditions of electroplating are: electroplating temperature 80°C, current density 5mA / cm 2 , pH=10, time is 3h.

[0042] Experimental Example 2 Preparation of low diffusion Pt-ZrO2 coating for high temperature alloy protection

[0043] S1. Take the second-generation nickel-based single crystal high-temperature alloy RenéN5 with a size of Φ15×2mm as the substrate; then polish the substrate with 180#, 600#, and 800# SiC sandpaper in turn, and sandblast the sample under a pressure of 0.3MPa. The sandblasted sample is deoiled in a 50g / L boiling sodium hydroxide aqueous solution for 10 minutes, and then ultrasonically cleaned in acetone and alcohol for 10 minutes respectively to obtain the pretreated substrate;

[0044] S2. The pretreated substrate is used as a cathode, and a nickel plate is used as an anode, and is placed in a platinum plating solution containing ZrO2 particles for electroplating; the coating thickness is 5 μm;

[0045] S3. The electroplated sample was vacuum annealed at a temperature of 1050°C for 1 h and a vacuum degree of 10 -3 Pa, the heating rate is less than 10°C / min, and after the annealing is completed, the low-diffusion Pt-ZrO2 coating for high-temperature alloy protection is obtained.

[0046] The preparation method of the platinum plating solution containing ZrO2 particles is as follows: ZrO2 particles (100nm) are added to the platinum plating solution, and the solution is stirred to obtain a platinum plating solution containing 15g / L ZrO2 particles; the platinum plating solution is prepared by the following method: Pt(NH3)2(NO2)2 and NaNO2 are added to water, and the solution is stirred to obtain the platinum plating solution; wherein the contents of Pt(NH3)2(NO2)2 and NaNO2 in the platinum plating solution are: Pt(NH3)2(NO2)2 10g / L, NaNO2 10g / L respectively;

[0047] The specific conditions of electroplating are: electroplating temperature 80°C, current density 5mA / cm 2 , pH=10, time is 3h.

[0048] Comparative Example 1 Preparation of low diffusion Pt-Y2O3 coating for high temperature alloy protection

[0049] S1. Take the second-generation nickel-based single crystal high-temperature alloy RenéN5 with a size of Φ15×2mm as the substrate; then polish the substrate with 180#, 600#, and 800# SiC sandpaper in turn, and sandblast the sample under a pressure of 0.3MPa. The sandblasted sample is deoiled in a 50g / L boiling sodium hydroxide aqueous solution for 10 minutes, and then ultrasonically cleaned in acetone and alcohol for 10 minutes respectively to obtain the pretreated substrate;

[0050] S2. The pretreated substrate is used as a cathode and a nickel plate is used as an anode, and is placed in a platinum plating solution containing Y2O3 particles for electroplating; the coating thickness is 5μm;

[0051] S3. The electroplated sample was vacuum annealed at a temperature of 1050°C for 1 h and a vacuum degree of 10 -3 Pa, the heating rate is less than 10°C / min, and after the annealing is completed, the low-diffusion Pt-Y2O3 coating for high-temperature alloy protection is obtained.

[0052] The preparation method of the platinum plating solution containing Y2O3 particles is as follows: Y2O3 particles (100nm) are added to the platinum plating solution, and the solution is stirred to obtain a platinum plating solution containing 15g / L Y2O3 particles; the platinum plating solution is prepared by the following method: Pt(NH3)2(NO2)2 and NaNO2 are added to water, and the solution is stirred to obtain the platinum plating solution; wherein the contents of Pt(NH3)2(NO2)2 and NaNO2 in the platinum plating solution are: Pt(NH3)2(NO2)2 10g / L, NaNO2 10g / L respectively;

[0053] The specific conditions of electroplating are: electroplating temperature 80°C, current density 5mA / cm 2 , pH=10, time is 3h.

[0054] Comparative Example 2 Preparation of coating for high temperature alloy protection

[0055] S1. Take the second-generation nickel-based single crystal high-temperature alloy RenéN5 with a size of Φ15×2mm as the substrate; then polish the substrate with 180#, 600#, and 800# SiC sandpaper in turn, and sandblast the sample under a pressure of 0.3MPa. The sandblasted sample is deoiled in a 50g / L boiling sodium hydroxide aqueous solution for 10 minutes, and then ultrasonically cleaned in acetone and alcohol for 10 minutes respectively to obtain the pretreated substrate;

[0056] S2. The pretreated substrate is used as a cathode and a nickel plate is used as an anode, and is placed in a platinum plating solution for electroplating;

[0057] S3. The electroplated sample was vacuum annealed at a temperature of 1050°C for 1 h and a vacuum degree of 10 -3 Pa, the heating rate is less than 10℃ / min, and the coating for high-temperature alloy protection is obtained after annealing.

[0058] The preparation method of the platinum plating solution is as follows: Pt(NH3)2(NO2)2 and NaNO2 are added into water, and stirred evenly to obtain the platinum plating solution; wherein the contents of Pt(NH3)2(NO2)2 and NaNO2 in the platinum plating solution are respectively: Pt(NH3)2(NO2)2 10g / L, NaNO2 10g / L;

[0059] The specific conditions of electroplating are: electroplating temperature 80°C, current density 5mA / cm2 , pH=10, time is 3h.

[0060] from Figure 1 to Figure 4 The experimental results show that:

[0061] Can be obtained from Figure 1 a. Amplification of 1c Figure 1 As can be seen from Figures 1d and 1f, there are a small number of holes on the surface of the experimental Pt-CeO2 coating and the comparative Pt-Y2O3 coating, and the holes are doped with some white particles, which are Y and Ce powders respectively. Figure 1 Amplification of b Figure 1 As can be seen in Figure e, the surface of the Pt-ZrO2 coating is intact and there is no particle deposition. Figure 2 It can be seen that the experimental samples Pt-ZrO2 and Pt-CeO2 coatings in the deposited state and the comparative sample Pt-Y2O3 coatings prepared by the method all have ZrO2, CeO2 and Y2O3 nanoparticles deposited in the Pt coating.

[0062] from Figure 3 It can be seen that the experimental samples Pt-ZrO2 and Pt-CeO2 coatings quickly entered a slow weight gain period after a short period of rapid weight gain. For α-Al2O3, its growth rate is much lower than that of metastable θ and γ-Al2O3. Therefore, the metastable alumina in Pt-ZrO2 and Pt-CeO2 coatings quickly transformed into stable α-Al2O3; while the metastable alumina in Y2O3 coatings cannot quickly transform into stable α-Al2O3.

[0063] from Figure 4 It can be seen that the oxidation rate constant of the Pt-ZrO2 coating is the lowest both in the rapid weight gain stage and the stable weight gain stage; thus, its oxidation rate is significantly lower than that of the experimental Pt-CeO2 coating and the comparative Pt-Y2O3 coating. Figure 5 The mass change curve and rate constant curve of the comparative example Pt coating show that its oxidation rate is higher than or even significantly higher than that of the experimental samples Pt-ZrO2 and Pt-CeO2 coatings. It can be seen that the oxidation rate of the experimental sample is lower than or even significantly lower than that of the comparative sample, and the sample performance has been significantly optimized.

Claims

1. A low diffusion Pt-M for high temperature alloy protection x O y The method for preparing the coating is characterized in that: The following steps are included: Pre-treating the substrate to obtain a pre-treated substrate; The pretreated substrate is used as a cathode and placed in a composite plating solution for electroplating; The electroplated sample is subjected to vacuum annealing, and after the annealing, the low-diffusion Pt-M for high-temperature alloy protection is obtained. x O y coating; The composite plating solution contains M x O y Platinum plating solution for particles.

2. The low diffusion Pt-M for high temperature alloy protection according to claim 1 x O y The method for preparing the coating is characterized in that: The M x O y The platinum plating solution of the particles is prepared by the following method: M is added to the platinum plating solution. x O y The particles are stirred evenly to obtain the M-containing x O y Platinum plating solution for particles.

3. The low diffusion Pt-M for high temperature alloy protection according to claim 2 x O y The method for preparing the coating is characterized in that: Contains M x O y The platinum plating solution of the particles x O y The content of the particles is 10-20 g / L.

4. The low diffusion Pt-M for high temperature alloy protection according to claim 2 x O y The method for preparing the coating is characterized in that: The M x O y The particles are selected from CeO2 particles and / or ZrO2 particles.

5. The low diffusion Pt-M for high temperature alloy protection according to claim 2 x O y The method for preparing the coating is characterized in that: The platinum plating solution is an aqueous solution containing Pt(NH3)2(NO2)2 and NaNO2.

6. The low diffusion Pt-M for high temperature alloy protection according to claim 5 x O y The method for preparing the coating is characterized in that: The content of Pt(NH3)2(NO2)2 in the platinum plating solution is 8-15 g / L, and the content of NaNO2 is 8-15 g / L.

7. The low diffusion Pt-M for high temperature alloy protection according to claim 1 x O y The method for preparing the coating is characterized in that: The substrate is a second generation or higher nickel-based single crystal high-temperature alloy substrate.

8. The low diffusion Pt-M for high temperature alloy protection according to claim 1 x O y The method for preparing the coating is characterized in that: The specific conditions of the electroplating are: electroplating temperature 75-85°C, current density 4-6 mA / cm 2 , pH=10~12, time is 2.5h~3.5h.

9. The low diffusion Pt-M for high temperature alloy protection according to claim 1 x O y The method for preparing the coating is characterized in that: The specific conditions of the vacuum annealing are: annealing temperature is 1000-1100°C, heat preservation is 0.5-2h, vacuum degree is 10 -3 Pa, the heating rate is less than 5-15℃ / min.

10. Low diffusion Pt-M for high temperature alloy protection prepared by the preparation method according to any one of claims 1 to 9 x O y coating.

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