Metal / nitride double-layer coating resistant to 1000°c, and preparation method therefor and use thereof

Abstract

The present invention relates to a metal / nitride double-layer coating resistant to 1000°C, and a preparation method therefor and the use thereof. The metal / nitride double-layer coating comprises a metal intermediate layer and a nitride coating grown in sequence along a substrate. The nitride coating (3) consists of amorphous SixAlyCrzN1-x-y-z, wherein x, y and z represent atomic percent, x is 1%-60%, y is 0%-60%, and z is 0%-60%. Compared with the prior art, the metal / nitride double-layer coating, serving as a protective coating for a titanium-aluminum alloy or a titanium alloy, can withstand high-temperature (1000°C) environments, and can work stably for a long period of time in high-temperature environments, significantly improving the high-temperature oxidation resistance of the titanium alloy or the titanium-aluminum alloy.

Description

A metal / nitride bilayer coating resistant to 1000℃, its preparation method and application Technical Field

[0001] This invention relates to the field of metal surface treatment technology, and in particular to a metal / nitride bilayer coating resistant to 1000℃, its preparation method and application. Background Technology

[0002] Titanium alloys and titanium-aluminum alloys are widely used in aerospace, automotive, medical, and other technological fields due to their high specific strength, strong corrosion resistance, and excellent high-temperature mechanical properties. For example, high-temperature titanium alloys can operate at 600°C for extended periods, withstand continuous high-temperature working conditions, and can reach a short-term service temperature of 750°C under extreme high-temperature conditions. Titanium-aluminum alloys can operate for extended periods in high-temperature environments of 750°C, exhibiting superior high-temperature stability and creep resistance compared to high-temperature titanium alloys, and can reach a short-term service temperature of 950°C under extreme high-temperature conditions. However, titanium alloys struggle to form a dense oxide layer at high temperatures (e.g., above 500°C), and an oxygen-rich layer easily forms beneath the oxide layer. While titanium-aluminum alloys, due to their higher aluminum content, have better high-temperature oxidation resistance than titanium alloys, the oxide film may crack or peel off with increasing temperature or under thermal cycling conditions, leading to oxidation failure. High-temperature oxidation exposes the base metal, further triggering oxidation and corrosion problems, affecting the material's mechanical properties, and thus severely impacting its service life and reliability.

[0003] Therefore, developing a high-temperature oxidation-resistant coating is key to solving this problem. While existing protective coatings exhibit some high-temperature resistance at certain temperatures, most still suffer from issues such as coating peeling and oxide layer damage in environments above 600°C. Therefore, there is an urgent need for a new type of coating material, particularly one that can provide effective protection at 1000°C, thereby addressing the high-temperature oxidation problem of titanium-aluminum alloys and titanium alloys.

[0004] High-temperature oxidation-resistant coatings for titanium alloys or titanium-aluminum alloys mainly include aluminide and silicide metallic coatings, and ceramic-based coatings such as oxides and nitrides. Among numerous anti-oxidation materials, aluminide and silicide coatings are widely used for high-temperature protection due to their ability to form a protective oxide film on their surface. However, aluminide and silicide coatings may deplete aluminum and silicon due to the formation of the oxide film and diffusion into the titanium substrate, leading to degradation under prolonged high-temperature exposure. Furthermore, due to the chemical incompatibility between these coatings and the titanium or titanium alloy substrate, brittle phases may form at the coating / substrate interface, thereby reducing the mechanical properties of the interface. Glass-ceramic (MgO-SiO2-TiO2), nitride (TiAlN), and MAX phase (Cr2AlC) coatings have also attracted attention due to their good chemical stability and excellent high-temperature oxidation resistance. However, the inherent low ductility of ceramic coatings, poor adhesion to the substrate, and thermal mismatch between the coating and the substrate, especially during cyclic oxidation during service, limit the application of these coatings. Summary of the Invention

[0005] The purpose of this invention is to provide a metal / nitride double-layer coating that can withstand 1000℃, its preparation method and application. The metal / nitride double-layer coating, as a protective coating for titanium-aluminum alloys or titanium alloys, can withstand high temperature (1000℃) environment and can work stably for a long time in high temperature environment, significantly improving the high temperature oxidation resistance of titanium alloys or titanium-aluminum alloys.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A metal / nitride bilayer coating resistant to 1000℃, comprising a metal intermediate layer and a nitride coating grown sequentially along the substrate.

[0008] The nitride coating is made of amorphous Si x Al y Cr z N 1-x-y-z The composition is defined as follows: x, y, and z represent atomic percentages, where x ranges from 1% to 60%, y ranges from 0% to 60%, and the sum of the atomic percentages of Si, Al, Cr, and N is 100%.

[0009] Furthermore, the matrix comprises titanium-aluminum alloy and titanium alloy.

[0010] Furthermore, the metal interlayer is composed of one or more metals such as Cr, Ta, Nb, Mo, or Zr.

[0011] Furthermore, the thickness of the nitride coating is 500-7000 nanometers.

[0012] Furthermore, the thickness of the metal interlayer is 20–5000 nanometers.

[0013] This invention also provides a method for preparing a metal / nitride bilayer coating resistant to 1000℃, the specific steps of which are as follows:

[0014] S1. Argon ion bombardment is performed on the substrate surface using magnetron sputtering;

[0015] S2. Argon gas is introduced, and a metal intermediate layer is deposited on the substrate surface using magnetron sputtering;

[0016] S3. Argon and nitrogen are introduced, and magnetron sputtering is used to deposit a nitride coating on the surface of the metal intermediate layer to form a metal / nitride double coating.

[0017] Furthermore, in step S1, the substrate is a pretreated substrate, and the pretreatment step includes acetone cleaning or mechanical surface polishing.

[0018] Furthermore, in step S1, the argon ion bombardment time is 5-30 minutes.

[0019] Furthermore, in step S2, the flow rate of the argon gas is 10–30 sccm.

[0020] Furthermore, in step S2, the power of the metal target material of the metal intermediate layer is 50-1000W.

[0021] Further, in step S3, the flow rate of the argon gas is 10-40 sccm, and the flow rate of the nitrogen gas is 5-30 sccm.

[0022] Further, in step S3, the nitride coating is made of amorphous Si x Al y Cr z N 1-x-y-z The composition, wherein x, y and z represent atomic percentages, x is 1% to 60%, y is 0% to 60%, and z is 0% to 60%; the power of the Si target is 50-1000W, the power of the Al target is 0-1000W, the power of the Cr target is 0-1000W, and the heating temperature of the substrate during magnetron sputtering is 20-500℃.

[0023] Furthermore, the present invention also provides an application of a metal / nitride bilayer coating resistant to 1000°C, wherein the metal / nitride bilayer coating is used to prepare a protective coating for titanium-aluminum alloys and titanium alloy surfaces.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. This invention employs microstructure precision control technology to prepare amorphous Si. x Al y Crz N 1-x-y-z The coating, along with the metal interlayer, plays a role in promoting the bonding between the nitride coating and the substrate, controlling the interdiffusion rate between the coating and the substrate, and mitigating thermal mismatch between the coating and the substrate.

[0026] 2. This invention achieves precise control of Si x Al y Cr z N 1-x-y-z The structure and elemental composition achieve high thermal stability and high-temperature oxidation resistance in the nitride coating. The provided nitride protective coating exhibits extremely high high-temperature stability, providing oxidation protection against oxidation of titanium-aluminum alloys or titanium alloys for hundreds of hours in air environments up to 1000°C. This significantly improves the high-temperature oxidation and corrosion resistance of titanium-aluminum alloys or titanium alloys, greatly enhancing their application in hot-end components such as aero-engines.

[0027] 3. The preparation method of the metal / nitride bilayer coating described in this invention is simple, the coating has strong adhesion, and it is suitable for large-scale industrial applications. Attached Figure Description

[0028] Figure 1 is a schematic diagram of the structure of the metal / nitride bilayer coating of the present invention;

[0029] Figure 2 is a schematic diagram of the metal / nitride bilayer coating prepared in Example 1 providing air environment protection for titanium-aluminum alloy at 1000°C;

[0030] Figure 3 is a schematic diagram of the metal / nitride bilayer coating prepared in Example 1 providing air environment protection for titanium-aluminum alloy at 900°C;

[0031] Figure 4 is a schematic diagram of the metal / nitride bilayer coating prepared in Example 3 that provides protection of titanium-aluminum alloy against air environment at 1000°C.

[0032] Explanation of the attached figures: 1. Substrate; 2. Metal intermediate layer; 3. Nitride coating. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0034] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0035] Example 1

[0036] This embodiment provides a method for preparing a metal / nitride bilayer coating, the specific steps of which are as follows:

[0037] S1. The surface of the titanium-aluminum alloy substrate is cleaned with acetone to obtain the pretreated titanium-aluminum alloy substrate.

[0038] S2. Place the pretreated titanium-aluminum alloy substrate obtained in step S1 into the sample holder of the magnetron sputtering cavity and fix it, then evacuate to 8×10⁻⁶. -6 Approximately mBar or less; apply a bias voltage of -600V to the substrate and introduce argon gas at a flow rate of 20sccm. After 20 minutes, turn off the bias voltage to obtain a titanium-aluminum alloy substrate bombarded with argon ions.

[0039] S3. Deposit a metal intermediate layer on the surface of the titanium-aluminum alloy substrate after argon ion bombardment obtained in step S2: Set the power applied to the Ta and Cr targets to 400W, and the substrate rotates at a speed of 5r / min to achieve co-deposition of Ta and Cr. At the same time, the heating temperature of the substrate is set to 200℃. After 30 minutes, the power is turned off to obtain metal intermediate layer 2.

[0040] S4. A nitride coating 3 is deposited on the metal intermediate layer 2 obtained in step S3. The power applied to the Si target, Al target, and Cr target is 700W, 100W, and 50W, respectively. The substrate rotates at a speed of 3r / min to achieve co-deposition of Si, Al, and Cr. At this time, the argon flow rate is 20sccm and the nitrogen flow rate is 5sccm. The heating temperature of the substrate is set to 200℃. After 2 hours, the power is turned off to form a metal / nitride double layer coating.

[0041] The metal / nitride double-layer coating sample was taken out and placed in an air furnace at 1000℃ for 100 hours to test the high-temperature protection of the coating on the titanium-aluminum alloy. As shown in Figure 2, the metal / nitride double-layer coating achieved excellent protection for the titanium-aluminum alloy. The coating showed no cracks, no peeling, and no oxidation of the substrate.

[0042] Example 2

[0043] This embodiment provides a method for preparing a metal / nitride bilayer coating, the specific steps of which are as follows:

[0044] S1. The surface of the titanium alloy substrate is mechanically polished to obtain a pretreated titanium alloy substrate.

[0045] S2. Place the pretreated titanium alloy substrate obtained in step S1 into the sample holder of the magnetron sputtering cavity and fix it, then evacuate to 8×10⁻⁶. -6 Approximately mBar or less; apply a bias voltage of -600V to the substrate and introduce argon gas at a flow rate of 20sccm. After 10 minutes, turn off the bias voltage to obtain a titanium alloy substrate bombarded with argon ions.

[0046] S3. Deposit a metal intermediate layer on the surface of the titanium alloy substrate after argon ion bombardment obtained in step S2: Set the power applied to the Zr target to 300W, and set the heating temperature of the substrate to 50℃. Turn off the power after 5 minutes to obtain metal intermediate layer 2.

[0047] S4. A nitride coating 3 is deposited on the metal intermediate layer 2 obtained in step S3. The power applied to the Si target, Al target, and Cr target is 900W, 500W, and 0W, respectively. The substrate rotates at a speed of 5r / min to achieve co-deposition of Si, Al, and Cr. At this time, the argon flow rate is 40sccm and the nitrogen flow rate is 30sccm. The heating temperature of the substrate is set to 50℃. After 4 hours, the power is turned off to form a metal / nitride double layer coating.

[0048] The metal / nitride double-layer coating sample was taken out and placed in an air furnace at 900℃ for 100 hours to test the high-temperature protection of the coating on the titanium alloy. As shown in Figure 3, the metal / nitride double-layer coating achieved excellent protection for the titanium-aluminum alloy. The coating showed no cracks, no peeling, and no oxidation of the substrate.

[0049] Example 3

[0050] This embodiment provides a method for preparing a metal / nitride bilayer coating, the specific steps of which are as follows:

[0051] S1. The surface of the titanium-aluminum alloy substrate is mechanically ground and polished to obtain the pretreated titanium-aluminum alloy substrate.

[0052] S2. Place the pretreated titanium-aluminum alloy substrate obtained in step S1 into the sample holder of the magnetron sputtering cavity and fix it, then evacuate to 8×10⁻⁶. -6 Approximately mBar or less; apply a bias voltage of -600V to the substrate and introduce argon gas at a flow rate of 20sccm. After 15 minutes, turn off the bias voltage to obtain a titanium-aluminum alloy substrate bombarded with argon ions.

[0053] S3. Deposit a metal intermediate layer on the surface of the titanium-aluminum alloy substrate after argon ion bombardment obtained in step S2: Set the power applied to the Mo target and Nb target to 400W, and the substrate rotates at a speed of 5r / min to achieve co-deposition of Mo and Nb. At the same time, the heating temperature of the substrate is set to 200℃. After 15 minutes, the power is turned off to obtain metal intermediate layer 2.

[0054] S4. A nitride coating 3 is deposited on the metal intermediate layer 2 obtained in step S2. The power applied to the Si target, Al target, and Cr target is 800W, 200W, and 100W, respectively. The substrate rotates at a speed of 5r / min to achieve co-deposition of Si, Al, and Cr. At this time, the argon flow rate is 35sccm and the nitrogen flow rate is 15sccm. The heating temperature of the substrate is set to 200℃. After 4 hours, the power is turned off to form a metal / nitride double layer coating.

[0055] The metal / nitride double-layer coating sample was taken out and placed in an air furnace at 1000℃ for 50 hours to test the high-temperature protection of the coating on the titanium-aluminum alloy. As shown in Figure 4, the metal / nitride double-layer coating achieved excellent protection for the titanium-aluminum alloy. The coating showed no cracks, no peeling, and no oxidation of the substrate.

[0056] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A metal / nitride bilayer coating resistant to 1000℃, characterized in that, Includes a metal interlayer (2) and a nitride coating (3) grown sequentially along the substrate (1), The nitride coating (3) is made of amorphous Si x Al y Cr z N 1-x-y-z The composition is defined as follows: x, y, and z represent atomic percentages, with x ranging from 1% to 60%, y from 0% to 60%, and z from 0% to 60%.

2. The metal / nitride dual-layer coating resistant to 1000℃ according to claim 1, characterized in that, The substrate (1) includes titanium-aluminum alloy and titanium alloy.

3. The metal / nitride dual-layer coating resistant to 1000℃ according to claim 1, characterized in that, The metal intermediate layer (2) is composed of one or more metals such as Cr, Ta, Nb, Mo or Zr.

4. The metal / nitride dual-layer coating resistant to 1000℃ according to claim 1, characterized in that, The thickness of the nitride coating (3) is 500-7000 nanometers; The thickness of the metal intermediate layer (2) is 20 to 5000 nanometers.

5. A method for preparing a metal / nitride bilayer coating resistant to 1000℃ as described in any one of claims 1-4, characterized in that, The specific steps are as follows: S1. Argon ion bombardment is performed on the surface of the substrate (1) by magnetron sputtering; S2. Argon gas is introduced and magnetron sputtering is used to deposit a metal intermediate layer (2) on the surface of the substrate (1); S3. Argon and nitrogen are introduced, and magnetron sputtering is used to deposit a nitride coating (3) on the surface of the metal intermediate layer (2) to form a metal / nitride double coating.

6. The method for preparing a metal / nitride bilayer coating resistant to 1000℃ according to claim 5, characterized in that, In step S1, the substrate (1) is a pretreated substrate (1), and the pretreatment step includes acetone cleaning or mechanical surface polishing. In step S1, the argon ion bombardment time is 5-30 minutes.

7. The method for preparing a metal / nitride bilayer coating resistant to 1000℃ according to claim 5, characterized in that, In step S2, the flow rate of the argon gas is 10–30 sccm; In step S2, the power of the metal target material of the metal intermediate layer (2) is 50-1000W.

8. The method for preparing a metal / nitride bilayer coating resistant to 1000℃ according to claim 5, characterized in that, In step S3, the flow rate of argon is 10-40 sccm, and the flow rate of nitrogen is 5-30 sccm.

9. The method for preparing a metal / nitride bilayer coating resistant to 1000℃ according to claim 5, characterized in that, In step S3, the nitride coating (3) is made of amorphous Si x Al y Cr z N 1-x-y-z The composition, wherein x, y and z represent atomic percentages, x is 1% to 60%, y is 0% to 60%, and z is 0% to 60%; the power of the Si target is 50-1000W, the power of the Al target is 0-1000W, the power of the Cr target is 0-1000W, and the heating temperature of the substrate during magnetron sputtering is 20-500℃.

10. An application of a metal / nitride bilayer coating resistant to 1000°C as described in any one of claims 1-4, characterized in that, The metal / nitride bilayer coating is used to prepare a protective coating for titanium-aluminum alloys and titanium alloy surfaces.

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