High-temperature anti-oxidation low-diffusion nickel-platinum-aluminum coating and preparation process thereof

Abstract

The invention relates to the technical field of high-temperature coatings, in particular to a high-temperature anti-oxidation low-diffusion nickel-platinum-aluminum coating and a preparation process thereof.The coating comprises a beta-phase layer, a gamma '-beta transition layer, a gamma'-phase layer and a platinum layer which are sequentially distributed layer by layer from outside to inside; the preparation process comprises the following steps: preparing the platinum layer on the surface of the substrate in a magnetron sputtering manner; preparing a gamma'phase layer on the surface of the platinum layer by adopting a multi-arc ion plating mode; preparing a gamma '-beta transition layer on the surface of the gamma' phase layer; and preparing a beta-phase layer on the surface of the gamma '-beta transition layer. The high-temperature anti-oxidation low-diffusion nickel-platinum-aluminum coating and the preparation process thereof aim at solving the problem that a platinum-aluminum coating is poor in high-temperature oxidation resistance.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature coatings, and in particular to a high-temperature oxidation-resistant low-diffusion nickel-platinum-aluminum coating and a preparation process thereof. Background Art

[0002] The metal bonding layer is located between the ceramic surface layer and the metal substrate. On the one hand, it can improve the physical compatibility of the metal substrate and the ceramic surface layer, and on the other hand, it can alleviate the mismatch of thermal expansion coefficients between the ceramic layer and the metal substrate.

[0003] Platinum aluminum coating is widely used in the bonding layer of thermal barrier coating of commercial aircraft engines due to its excellent high-temperature oxidation resistance. GE, Pratt & Whitney and Rolls-Royce of the United States all use platinum aluminum coating as the main metal bonding layer of thermal barrier coating of commercial aircraft engines. The composition of the coating is the structure of β-(Ni,Pt)Al, which is because the aluminum content in the β phase is high and the high-temperature oxidation resistance is good. However, through research, it is found that the content of aluminum in the coating and nickel in the substrate is quite different, and there is a problem of element mutual diffusion. For the substrate, the outward diffusion of nickel will cause the precipitation of refractory elements in the substrate and the formation of secondary reaction zone (SRZ), which reduces the high-temperature mechanical properties of high-temperature alloys; for the coating, the loss of aluminum will cause the coating to transform from the β phase with better oxidation resistance to the γ' or even γ-Ni phase, which reduces the high-temperature oxidation resistance of the coating, causes the wrinkles of the coating, and then threatens the adhesion of the outer ceramic layer.

[0004] In response to the interdiffusion problem caused by the large difference in element content between the substrate and the coating, the team of Japanese scholars Sato first proposed the concept of equilibrium phase (EQ) coating. Sato's team prepared two coatings, γ' and γ, on the surface of the high-temperature alloy G-TMS-82+. Since the coating and the substrate are in a thermodynamic equilibrium state, the trend of element interdiffusion is suppressed. However, due to the low aluminum content in the coating, the coating's resistance to high-temperature oxidation is poor. After 300 hours of high-temperature oxidation, wrinkles of varying degrees appeared on the surface, and the γ phase coating even peeled off, which seriously reduced the life of the thermal barrier coating.

[0005] Therefore, the inventor provides a high-temperature oxidation-resistant low-diffusion nickel-platinum-aluminum coating and a preparation process thereof. Summary of the invention

[0006] (1) Technical issues to be solved

[0007] The embodiment of the present invention provides a high-temperature oxidation-resistant low-diffusion nickel-platinum-aluminum coating and a preparation process thereof, which solves the technical problem that the platinum-aluminum coating has poor high-temperature oxidation resistance.

[0008] (2) Technical solution

[0009] The first aspect of the present invention provides a high-temperature oxidation-resistant low-diffusion nickel-platinum-aluminum coating, comprising a β phase layer, a γ'-β transition layer, a γ' phase layer and a platinum layer distributed layer by layer from the outside to the inside.

[0010] Furthermore, the total thickness of the coating is ≤50 μm.

[0011] Furthermore, the thickness ratio of the β phase layer, the γ'-β transition layer and the γ' phase layer is 1:2:2.

[0012] The second aspect of the present invention provides a preparation process of a high temperature oxidation resistant low diffusion nickel platinum aluminum coating, comprising the following steps:

[0013] A platinum layer is prepared on the substrate surface by magnetron sputtering;

[0014] A γ' phase layer is prepared on the surface of the platinum layer by multi-arc ion plating;

[0015] preparing a γ'-β transition layer on the surface of the γ' phase layer;

[0016] A β phase layer is prepared on the surface of the γ'-β transition layer.

[0017] Furthermore, the platinum layer is prepared on the surface of the substrate by magnetron sputtering, specifically:

[0018] After ion bombardment cleaning, turn on the magnetron sputtering power supply, and when the platinum layer reaches a preset thickness, close the platinum target protection cover.

[0019] Furthermore, the multi-arc ion plating method is used to prepare the γ' phase layer on the surface of the platinum layer, specifically:

[0020] The γ' phase layer is prepared on the surface of the platinum layer by multi-arc ion plating in a vacuum chamber, and the composition of the target material is Ni3Al alloy.

[0021] Furthermore, arc targets are respectively arranged on two opposite sides of the vacuum chamber, and the arc current and the coating time are determined by the thickness of the γ' phase layer.

[0022] Furthermore, the cathode arc source is a permanent magnet plus an electromagnetic composite magnetic field.

[0023] Furthermore, the γ'-β transition layer is prepared on the surface of the γ' phase layer, specifically:

[0024] The evaporation boat power is turned on to prepare a γ'-β transition layer on the surface of the γ' phase layer. The working current is determined by the melting state of the aluminum wire on the evaporation boat, and the feeding rate of the aluminum wire is determined by the deposition rate of the γ'-β transition layer.

[0025] Furthermore, the material of the evaporation boat is boron carbide.

[0026] Furthermore, the feed rate of the aluminum wire is 100-250 mm / min.

[0027] Furthermore, the operating current of the evaporation boat is 550-700A.

[0028] (3) Beneficial effects

[0029] In summary, the present invention adopts a transition layer approach in the form of an inner layer of γ' phase, an outer layer of β phase, and a γ'-β transition layer formed in the middle to construct a balanced phase coating, reduce the diffusion potential between the β phase coating and the substrate, and achieve a combination of low mutual diffusion potential between the inner layer of the coating and the substrate and resistance to high temperature oxidation of the outer layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments of the present invention are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 This is a cross-sectional microstructure diagram of a high-temperature oxidation-resistant, low-diffusion nickel-platinum-aluminum coating provided by an embodiment of the present invention;

[0032] Figure 2 This is a cross-sectional microstructure diagram of a high-temperature oxidation-resistant, low-diffusion nickel-platinum-aluminum coating provided by an embodiment of the present invention;

[0033] Figure 3 This is an element distribution curve diagram of a high-temperature oxidation-resistant low-diffusion nickel-platinum-aluminum coating provided by an embodiment of the present invention;

[0034] Figure 4 This is a structural front view of a high-temperature oxidation-resistant low-diffusion nickel-platinum-aluminum coating preparation device provided by an embodiment of the present invention;

[0035] Figure 5 It is a structural axial view of a high-temperature oxidation-resistant and low-diffusion nickel-platinum-aluminum coating preparation device provided by an embodiment of the present invention.

[0036] In the figure:

[0037] A-nickel atomic ratio curve; B-aluminum atomic ratio curve; 1-arc target; 2-test piece; 3-magnetron sputtering target; 4-aluminum wire; 5-evaporation boat; 6-gas ion source. DETAILED DESCRIPTION

[0038] The following detailed description of the embodiments of the present invention is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention, that is, the present invention is not limited to the described embodiments.

[0039] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] Figure 1 It is a microstructure diagram of a high-temperature oxidation-resistant low-diffusion nickel-platinum-aluminum coating provided by an embodiment of the present invention. The coating may include a β phase layer, a γ'-β transition layer, a γ' phase layer and a platinum layer distributed layer by layer from the outside to the inside.

[0041] In the above embodiment, the total thickness of the coating is ≤50 μm, and the thickness ratio of the β phase layer, the γ'-β transition layer and the γ' phase layer is 1:2:2. Figure 2 As shown in the figure, when the total coating thickness is controlled within 50μm, the study shows that when the thickness ratio of the inner γ' phase, the middle γ'-β transition layer, and the outer β phase is about 1:2:2, the thermal cycle (1100℃) oxidation performance gain is the least (only 0.52mg / cm 2 ). From the trends of the nickel atomic ratio curve A and the aluminum atomic ratio curve B, it can be seen that the proportions of nickel and aluminum in the inner layer of the γ' phase, the middle γ'-β transition layer and the outer layer of the β phase are different. Among them, when the thickness of the inner layer γ' coating is low, the substrate and the inner layer γ' coating diffuse rapidly, and a γ / γ' structure will be formed soon, and refractory elements will precipitate, reducing the performance of the coating; when the thickness of the transition layer is low, the aluminum element diffuses rapidly, and as the aluminum element increases in γ', it transforms to β at high temperature. At this time, the mismatch of the interface lattice structure increases, which is easy to cause wrinkling and peeling; when the thickness of the β outer layer is not enough, the coating's resistance to high-temperature oxidation decreases, and the oxidation weight gain increases.

[0042] Figure 3 is a schematic flow chart of a preparation process of a high temperature oxidation resistant low diffusion nickel platinum aluminum coating provided by an embodiment of the present invention, see Figure 3 , the method may include the following steps:

[0043] S100, preparing a platinum layer on the surface of the substrate by magnetron sputtering.

[0044] Specifically, the structure of the ion bombardment cleaning equipment is as follows: Figure 4-5 As shown in the figure, after ion bombardment cleaning, the magnetron sputtering power supply is turned on, and when the platinum layer reaches the preset thickness, the platinum target protection cover is closed. The vacuum degree in the chamber is maintained at 10 -3 Pa~10 -4Pa; high-pressure ion bombardment system, including anode layer gas ion source power supply and bias power supply, the effective glow area needs to cover the workpiece; magnetron sputtering target 3 is located behind the test piece 2, and the material is high-purity platinum sheet. Because the platinum target is expensive, the outer layer of the platinum target is designed with a protective cover to avoid contamination of the platinum sheet during the subsequent nickel-aluminum coating preparation process; gas path and control system, using a high-precision gas flowmeter to control the gas (mainly compressed air and argon) flow; two cathode arc targets, used to prepare γ' coating; aluminum wire feeding and evaporation mechanism, used to regulate the coating phase composition, to achieve the transition from γ' to β. Hang the cleaned test piece into the vacuum chamber, first turn on the vacuum pump to reach the required vacuum degree, pass argon gas, turn on the power supply (1500~1800V) and bias power supply (100V) of the gas ion source 6 of the anode layer, and generate a glow area. Use argon ions to bombard and clean the surface of the test piece to improve the bonding strength of the subsequent deposited film layer. After 5 to 10 minutes of ion bombardment cleaning, the magnetron sputtering power supply (14 to 16 kW) is turned on. The sputtering time is determined according to the required thickness of the platinum layer. After the platinum layer reaches the required thickness, the platinum target protection cover is closed to prevent contamination by subsequent processes.

[0045] S200, preparing a γ' phase layer on the surface of the platinum layer by multi-arc ion plating.

[0046] Specifically, the structure of the multi-arc ion plating equipment is as follows: Figure 4-5 As shown, a γ' phase layer is prepared on the surface of a platinum layer by multi-arc ion plating in a vacuum chamber, and the target material is Ni3Al alloy. The cathode arc source is a permanent magnet plus an electromagnetic composite magnetic field. In order to further ensure the uniformity of the coating, a double arc source is used here, that is, an arc target 1 is set on each side of the vacuum chamber, and the arc current (generally 50-60A) and the coating time are determined according to the required coating thickness.

[0047] S300, preparing a γ'-β transition layer on the surface of the γ' phase layer.

[0048] Specifically, the structure of the transition layer preparation equipment is as follows: Figure 4-5As shown, the evaporation boat power supply is turned on to prepare the γ'-β transition layer on the surface of the γ' phase layer. Its working current is determined by the melting state of the aluminum wire 4 on the evaporation boat 5, and the feed rate of the aluminum wire 4 is determined by the deposition rate of the γ'-β transition layer. After obtaining the γ' phase coating of the required thickness, the evaporation boat power supply is turned on and the current is 550-700A. The current is determined by the melting state of the aluminum wire 4 on the evaporation boat 5. The standard is that under this current, the aluminum wire 4 just touches the evaporation boat 5 and melts into aluminum liquid, and the aluminum liquid evaporates rapidly, and a small amount of aluminum liquid pool is always maintained on the surface of the evaporation boat 5. The material of the evaporation boat 5 is boron carbide. The continuous wire feeding mechanism is composed of a servo motor, an aluminum wire disc, an aluminum wire feed pipe and other structures. One end of the aluminum wire 4 is wound on the disc, and the other end is guided to the evaporation boat 5 through the feed pipe. The feed rate of the aluminum wire 4 can be controlled by the motor. The feed rate of the aluminum wire 4 needs to be determined by the deposition rate of the required coating. Here, the feed rate of the aluminum wire 4 is 100-250mm / min.

[0049] S400, preparing a β phase layer on the surface of the γ'-β transition layer.

[0050] Specifically, the excellent high-temperature oxidation resistance of the β-phase coating comes from the high aluminum content therein, but aluminum will diffuse elements with the substrate, causing the coating to fail. According to Fick's first law, to reduce the interdiffusion of elements, either reduce the interdiffusion coefficient or reduce the diffusion potential. Here, a transition layer is used to construct an equilibrium phase coating to reduce the diffusion potential between the β-phase coating and the substrate. The nickel in the coating of the present invention does not come from the substrate, but from the target material, avoiding the formation of an interdiffusion zone.

[0051] Example 1

[0052] 1) Pretreatment: The test pieces were polished on 120#, 200#, 400#, 800#, and 1200# gauze papers in turn, and then ultrasonically cleaned in a 60°C NaOH aqueous solution (10 g / L) and a propanol solution for 10 minutes in turn.

[0053] 2) Ion bombardment cleaning: Equipment diagram as shown below Figure 4-5 As shown, the vacuum chamber is a bedroom with a front door structure, including a vacuum system, including a mechanical pump, a molecular pump, etc. The vacuum degree in the chamber is maintained at 10 -3 Pa; Hang the cleaned test piece into the vacuum chamber, first turn on the vacuum pump to reach the required vacuum degree, introduce argon gas, turn on the anode layer gas ion source power supply (1800V) and bias power supply (300V), and generate a glow zone. Use argon ions to bombard and clean the surface of the test piece to improve the bonding strength of the subsequent deposited film layer.

[0054] 3) Magnetron sputtering platinum layer: After ion bombardment cleaning for 30 minutes, the magnetron sputtering power supply (16 kW) was turned on, and the sputtering time was 20 minutes to obtain a platinum layer with a thickness of 3 μm.

[0055] 4) Preparation of γ' phase coating: The γ' phase coating was prepared by multi-arc ion plating. The target material was Ni3Al alloy, the cathode arc source was a permanent magnet plus an electromagnetic composite magnetic field, a double arc source was used, a single arc current was 50A, and the ion plating time was 8 minutes, resulting in a γ' phase coating with a thickness of 6 μm.

[0056] 5) Preparation of the transition layer from γ' phase to β phase: After obtaining the γ' phase coating, the evaporation boat power supply was turned on, the current was 550A, and the feed rate of the aluminum wire was 200mm / min. As the aluminum ion concentration gradually increased, a γ'-β phase transition layer with a thickness of 10μm was formed. At this time, the aluminum wire feed rate was reduced to 120mm / min, and the deposition was continued for 10min. As the coating continued, a β phase with better high temperature oxidation resistance was formed in the outer layer. The microstructure of the prepared coating cross section is shown in the figure. Figure 1 shown.

[0057] It should be clear that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. In addition, for the sake of brevity, a detailed description of known methods and technologies is omitted here.

[0058] The above are only embodiments of the present application and are not limited to the present application. For those skilled in the art, the present application may have various changes and variations without departing from the scope of the present invention. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A high temperature, oxidation resistant, low diffusion nickel-platinum-aluminum coating, characterized in that: It includes a β phase layer, a γ'-β transition layer, a γ' phase layer and a platinum layer which are distributed layer by layer from the outside to the inside.

2. The high temperature oxidation resistant low diffusion nickel platinum aluminum coating according to claim 1, characterized in that: The total coating thickness is ≤50μm.

3. The high temperature oxidation resistant low diffusion nickel platinum aluminum coating according to claim 1, characterized in that: The thickness ratio of the β phase layer, the γ′-β transition layer and the γ′ phase layer is 1:2:

2.

4. A preparation process for a high temperature, oxidation resistant, low diffusion nickel-platinum-aluminum coating, characterized in that: The preparation process comprises the following steps: A platinum layer is prepared on the substrate surface by magnetron sputtering; A γ' phase layer is prepared on the surface of the platinum layer by multi-arc ion plating; preparing a γ'-β transition layer on the surface of the γ' phase layer; A β phase layer is prepared on the surface of the γ'-β transition layer.

5. The preparation process of the high temperature oxidation resistant low diffusion nickel platinum aluminum coating according to claim 4 is characterized in that: The method of preparing a platinum layer on the surface of the substrate by magnetron sputtering is specifically as follows: After ion bombardment cleaning, turn on the magnetron sputtering power supply, and when the platinum layer reaches a preset thickness, close the platinum target protection cover.

6. The preparation process of the high temperature oxidation resistant low diffusion nickel platinum aluminum coating according to claim 4 is characterized in that: The method of preparing the γ' phase layer on the surface of the platinum layer by multi-arc ion plating is specifically as follows: The γ' phase layer is prepared on the surface of the platinum layer by multi-arc ion plating in a vacuum chamber, and the composition of the target material is Ni3Al alloy.

7. The preparation process of the high temperature oxidation resistant low diffusion nickel platinum aluminum coating according to claim 4 is characterized in that: Arc targets are respectively arranged on two opposite sides of the vacuum chamber, and the arc current and the coating time are determined by the thickness of the γ' phase layer.

8. The preparation process of the high temperature oxidation resistant low diffusion nickel platinum aluminum coating according to claim 4 is characterized in that: The cathode arc source is a permanent magnet plus an electromagnetic composite magnetic field.

9. The preparation process of the high temperature oxidation resistant low diffusion nickel platinum aluminum coating according to claim 4, characterized in that: The step of preparing a γ'-β transition layer on the surface of the γ' phase layer is specifically as follows: The evaporation boat power is turned on to prepare a γ'-β transition layer on the surface of the γ' phase layer. The working current is determined by the melting state of the aluminum wire on the evaporation boat, and the feeding rate of the aluminum wire is determined by the deposition rate of the γ'-β transition layer.

10. The preparation process of the high temperature oxidation resistant low diffusion nickel platinum aluminum coating according to claim 9, characterized in that: The material of the evaporation boat is boron carbide.

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