Metal / nitride double-layer coating capable of resisting 1000 DEG C and preparation method and application of metal / nitride double-layer coating

Abstract

The invention relates to a 1000 DEG C-resistant metal / nitride double-layer coating and a preparation method and application thereof.The metal / nitride double-layer coating comprises a metal middle layer and a nitride coating which sequentially grow along a matrix, the nitride coating (3) is composed of amorphous SixAlyCrzN1-x-y-z, x, y and z represent atomic fraction percentages, x is 1%-60%, y is 0%-60%, and z is 0%-60%. Compared with the prior art, the metal / nitride double-layer coating serves as a protective coating for the titanium-aluminum alloy or the titanium alloy, can bear the high-temperature (1000 DEG C) environment and can stably work for a long time in the high-temperature environment, and the high-temperature oxidation resistance of the titanium alloy or the titanium-aluminum alloy is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal surface treatment, and in particular to a metal / nitride double-layer coating resistant to 1000 °C, a preparation method thereof, and an application thereof. Background Art

[0002] Titanium alloys and titanium aluminide alloys are widely used in various technical fields such as aerospace, automotive, and medical due to their high specific strength, strong corrosion resistance, and excellent high-temperature mechanical properties. For example, high-temperature titanium alloys can serve at 600 °C for a long time, can withstand continuous high-temperature working conditions, and can reach a short-term service temperature of 750 °C when dealing with extremely high-temperature working conditions; titanium aluminide alloys can serve in a high-temperature environment of 750 °C for a long time, and their high-temperature stability and creep resistance are superior to those of high-temperature titanium alloys, and the short-term service temperature can reach 950 °C in extremely high-temperature working conditions. However, titanium alloys are difficult to form a dense oxide layer at high temperatures (such as above 500 °C), and an oxygen-rich layer is likely to form on the lower surface of the oxide layer; titanium aluminide alloys have better high-temperature oxidation resistance than titanium alloys due to their high aluminum content. With the increase in temperature or under thermal cycling conditions, the oxide film may develop local cracks or fall off, resulting in the failure of its oxidation resistance. High-temperature oxidation exposes the base metal, further causing problems such as oxidation and corrosion, affecting the mechanical properties of the material, and thus seriously affecting its service life and reliability.

[0003] Therefore, developing a high-temperature oxidation-resistant coating has become the key to solving this problem. Although existing protective coatings have certain high-temperature resistance at certain temperatures, most still have problems such as coating peeling and oxide layer damage in high-temperature environments above 600 °C. For this reason, there is an urgent need for a new type of coating material, especially a coating that can provide effective protection at 1000 °C, so as to solve the high-temperature oxidation problems of titanium aluminide alloys and titanium alloys.

[0004] High-temperature oxidation-resistant coatings for titanium alloys or titanium aluminide alloys mainly include aluminide and silicide metal coatings, and ceramic-based coatings such as oxides and nitrides. Among many oxidation-resistant materials, aluminide and silicide coatings are widely used for high-temperature protection due to their ability to form a protective oxide film on the surface. However, aluminide and silicide coatings may degenerate under long-term high-temperature exposure due to the formation of the oxide film and diffusion into the titanium substrate, resulting in depletion of aluminum and silicon. In addition, due to the chemical incompatibility between these coatings and the titanium or titanium alloy substrate, a brittle phase may form at the coating / substrate interface, thereby reducing the mechanical properties of the interface. Glass ceramics (MgO-SiO2-TiO2), nitrides (TiAlN), and MAX phase (Cr2AlC) coatings have also attracted much 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 problems between the coating and the substrate, especially during cyclic oxidation during service, limit the application of these coatings. Summary of the Invention

[0005] The object of the present invention is to provide a metal / nitride double-layer coating resistant to 1000 °C, its preparation method and application. The metal / nitride double-layer coating, as a protective coating for titanium aluminide or titanium alloy, can withstand high-temperature (1000 °C) environment and can work stably for a long time in the high-temperature environment, significantly improving the high-temperature oxidation resistance of titanium alloy or titanium aluminide.

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] A metal / nitride double-layer coating resistant to 1000 °C, comprising a metal intermediate layer and a nitride coating growing sequentially along the substrate,

[0008] The nitride coating is composed of amorphous Si x Al y Cr z N 1-x-y-z wherein x, y and z represent atomic fraction percentages, x is 1% to 60%, y is 0% to 60%, and the sum of the atomic fraction percentages of Si, Al, Cr, and N is 100%.

[0009] Further, the substrate includes titanium aluminide and titanium alloy.

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

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

[0012] Further, the thickness of the metal intermediate layer is 20 - 5000 nanometers.

[0013] The present invention also provides a preparation method of a metal / nitride double-layer coating resistant to 1000 °C, and the specific steps are as follows:

[0014] S1. Using magnetron sputtering, argon ion bombardment is carried out on the surface of the substrate;

[0015] S2. Introducing argon gas, using magnetron sputtering, depositing a metal intermediate layer on the surface of the substrate;

[0016] S3. Introducing argon gas and nitrogen gas, using magnetron sputtering, depositing a nitride coating on the surface of the metal intermediate layer to form a metal / nitride double-layer coating.

[0017] Further, in step S1, the substrate is a pretreated substrate, and the pretreatment steps include acetone cleaning or mechanical surface grinding and polishing.

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

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

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

[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, in step S3, the nitride coating is composed of amorphous Si x Al y Cr z N 1-x-y-z wherein, x, y, and z represent atomic fraction percentages, x is 1% - 60%, y is 0% - 60%, and z is 0% - 60%; the power of the Si target is 50 - 1000 W, the power of the Al target is 0 - 1000 W, the power of the Cr target is 0 - 1000 W, and the heating temperature of the substrate during magnetron sputtering is 20 - 500 °C.

[0023] In addition, the present invention also provides an application of a metal / nitride double-layer coating resistant to 1000 °C, and the metal / nitride double-layer coating is used for preparing a protective coating on the surface of titanium aluminide alloy and titanium alloy.

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

[0025] 1. The present invention uses a microstructure precise control technology to prepare an amorphous Si x Al y Cr z N 1-x-y-z coating, and at the same time, the metal intermediate layer plays roles in promoting the bonding between the nitride coating and the substrate, controlling the interdiffusion rate between the interface coating and the substrate, and alleviating problems such as thermal mismatch between the coating and the substrate.

[0026] 2. The present invention realizes the high thermal stability and high-temperature oxidation resistance of the nitride coating by precisely regulating the Si x Al y Cr z N 1-x-y-z structure and the proportion of each element. The provided nitride protective coating has extremely high high-temperature stability, can achieve oxidation protection of titanium aluminide alloy or titanium alloy for hundreds of hours in an air environment up to 1000 °C, significantly improves the high-temperature oxidation and corrosion resistance of titanium aluminide alloy or titanium alloy, and can greatly improve the use of titanium aluminide alloy or titanium alloy in hot-end components such as aeroengines.

[0027] 3. The preparation method of the metal / nitride double-layer coating described in the present invention is simple, the coating adhesion is strong, and it is suitable for large-scale industrial applications. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of the metal / nitride double-layer coating of the present invention;

[0029] Figure 2 It is a schematic diagram of the metal / nitride double-layer coating prepared in Example 1 for protecting titanium aluminide alloy in an air environment at 1000 °C;

[0030] Figure 3 It is a schematic diagram of the metal / nitride double-layer coating prepared in Example 1 for protecting titanium aluminide alloy in an air environment at 900 °C;

[0031] Figure 4 It is a schematic diagram of the metal / nitride double-layer coating prepared in Example 3 for protecting titanium aluminide alloy in an air environment at 1000 °C.

[0032] Description of the drawing reference numerals: 1. Substrate, 2. Metal intermediate layer, 3. Nitride coating. Detailed Embodiments

[0033] The present invention will be described in detail below with reference to the drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation manner and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0034] Some embodiments of the present invention will be described in detail below with reference to the drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0035] Example 1

[0036] This example provides a method for preparing a metal / nitride double-layer coating, and the specific steps are as follows:

[0037] S1. The surface of the titanium aluminide alloy substrate is cleaned with acetone to obtain a pretreated titanium aluminide alloy substrate;

[0038] S2. The pretreated titanium aluminide alloy substrate obtained in step S1 is placed in the sample fixture of the magnetron sputtering chamber and fixed, and the vacuum is pumped to about 8×10 -6 mBar or below; a bias voltage of -600 V is applied to the substrate, and argon is introduced at a flow rate of 20 sccm. After 20 minutes, the bias voltage is turned off to obtain a titanium aluminide alloy substrate bombarded by argon ions;

[0039] S3. Deposit a metal intermediate layer on the surface of the titanium-aluminum alloy substrate bombarded by argon ions obtained in step S2: Set the power applied to the Ta target and the Cr target to 400 W, and the substrate rotates self at a speed of 5 r / min to achieve the co-deposition of Ta and Cr. At the same time, the set heating temperature of the substrate is 200 °C. After 30 minutes, turn off the power supply to obtain the metal intermediate layer 2;

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

[0041] Take out the metal / nitride double-layer coating sample, put the sample into an air furnace at 1000 °C for 100 hours, and test the protection of the coating at high temperature for the titanium-aluminum alloy, as Figure 2 shown. The metal / nitride double-layer coating achieves excellent protection for the titanium-aluminum alloy. The coating has no cracks, no peeling, and the substrate has no oxidation.

[0042] Example 2

[0043] This example provides a method for preparing a metal / nitride double-layer coating. The specific steps are as follows:

[0044] S1. Mechanically grind and polish the surface of the titanium alloy substrate to obtain a pretreated titanium alloy substrate;

[0045] S2. Put the pretreated titanium alloy substrate obtained in step S1 into the sample fixture of the magnetron sputtering cavity and fix it. Pump the vacuum to about 8×10 -6 mBar or below; Apply a bias voltage of -600 V to the substrate and introduce argon gas at a flow rate of 20 sccm. After 10 minutes, turn off the bias voltage to obtain a titanium alloy substrate bombarded by argon ions;

[0046] S3. Deposit a metal intermediate layer on the surface of the titanium alloy substrate bombarded by argon ions obtained in step S2: Set the power applied to the Zr target to 300 W. At the same time, the set heating temperature of the substrate is 50 °C. After 5 minutes, turn off the power supply to obtain the metal intermediate layer 2;

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

[0048] Take out the metal / nitride double - layer coating sample and put the sample into an air furnace at 900 °C for 100 hours to test the protection of the coating at high temperature for the titanium alloy, as Figure 3 shown, the metal / nitride double - layer coating achieves excellent protection for the titanium aluminide alloy. The coating has no cracks, no peeling, and the substrate has no oxidation.

[0049] Example 3

[0050] This example provides a method for preparing a metal / nitride double - layer coating, and the specific steps are as follows:

[0051] S1. Mechanically grind and polish the surface of the titanium aluminide alloy substrate to obtain a pretreated titanium aluminide alloy substrate;

[0052] S2. Put the pretreated titanium aluminide alloy substrate obtained in step S1 into the sample fixture of the magnetron sputtering chamber and fix it. Pump the vacuum to about 8×10 -6 mBar or below; Apply a bias voltage of - 600 V to the substrate and introduce argon at a flow rate of 20 sccm. After 15 minutes, turn off the bias voltage to obtain a titanium aluminide alloy substrate bombarded by argon ions;

[0053] S3. Deposit a metal intermediate layer on the surface of the titanium aluminide alloy substrate bombarded by argon ions obtained in step S2: Set the powers applied to the Mo target and Nb target to 400 W. The substrate rotates self - at a speed of 5 r / min to achieve the co - deposition of Mo and Nb. At the same time, the set heating temperature of the substrate is 200 °C. After 15 minutes, turn off the power supply to obtain the metal intermediate layer 2;

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

[0055] Take out the metal / nitride double - layer coating sample and put the sample into an air furnace at 1000 °C for 50 hours to test the protection of the coating at high temperature for the titanium aluminide alloy, asFigure 4 As shown, the metal / nitride double-layer coating achieves excellent protection for the titanium-aluminum alloy. The coating has no cracks, no peeling, and the substrate has no oxidation.

[0056] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A metal / nitride double-layer coating resistant to 1000°C, characterized in that: It comprises a metal intermediate layer (2) and a nitride coating (3) which are sequentially grown along a substrate (1), The nitride coating (3) is made of amorphous Si x Al y Cr z N 1-x-y-z Composition, wherein x, y and z represent atomic fraction percentages, x is 1% to 60%, y is 0% to 60%, and z is 0% to 60%.

2. A 1000°C resistant metal / nitride double-layer coating according to claim 1, characterized in that: The substrate (1) comprises titanium-aluminum alloy and titanium alloy.

3. The 1000°C resistant metal / nitride double-layer coating 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 1000°C resistant metal / nitride double-layer coating 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 1000°C resistant metal / nitride double-layer coating as claimed in any one of claims 1 to 4, characterized in that: The specific steps are as follows: S1, using magnetron sputtering to bombard the surface of the substrate (1) with argon ions; S2, introducing argon gas and using magnetron sputtering to deposit a metal intermediate layer (2) on the surface of the substrate (1); S3, introducing argon and nitrogen, and using magnetron sputtering to deposit a nitride coating (3) on the surface of the metal intermediate layer (2) to form a metal / nitride double-layer coating.

6. The method for preparing a 1000°C resistant metal / nitride double-layer coating according to claim 5, characterized in that: In step S1, the substrate (1) is a pre-treated substrate (1), and the pre-treatment 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 1000°C resistant metal / nitride double-layer coating according to claim 5, characterized in that: In step S2, the flow rate of the argon gas is 10 to 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 1000°C resistant metal / nitride double-layer coating according to claim 5, characterized in that: 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.

9. The method for preparing a 1000°C resistant metal / nitride double-layer coating 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 comprises: x, y and z represent atomic fraction 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°C.

10. An application of a 1000°C resistant metal / nitride double-layer coating as claimed in any one of claims 1 to 4, characterized in that: The metal / nitride double-layer coating is used to prepare protective coatings on the surfaces of titanium-aluminum alloys and titanium alloys.

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