A high-performance titanium alloy coating for use in space environments and a preparation method thereof

Abstract

The present invention discloses a high-performance titanium alloy coating for use in a space environment and a preparation method thereof, comprising a substrate, wherein the substrate is a Ti-6Al-4V titanium alloy material, and a chromium bonding layer, a Ti / TiN gradient layer, a main structural layer of TiAlN-CrN alternately arranged, and an external functional layer of diamond-like carbon (DLC) are sequentially arranged on the substrate. The coating of the present invention can be used in a space environment with extreme temperature changes, and solves the problems of wear resistance, corrosion resistance, and insufficient adhesion of traditional coatings of titanium alloy materials in extreme space environments.

Description

Technical Field

[0001] The invention relates to the technical field of surface engineering, and in particular to a high-performance titanium alloy coating applied to a space environment and a preparation method thereof. Background Art

[0002] Titanium alloy materials, especially Ti-6Al-4V alloy, have been widely used in the aerospace field due to their excellent specific strength and corrosion resistance. However, the low shear strength and wear resistance of this material limit its use in more extreme conditions, such as long-term exposure to high-speed particles, strong radiation and extreme temperature differences in space environments. Existing surface coating technologies, such as spraying MoS2 and sputtering DLC ​​(diamond-like carbon), although they have improved these properties to a certain extent, still have many limitations. For example, the adhesion of MoS2 coatings is low, and the adhesion of DLC coatings is also insufficient when applied under high temperature or high dynamic stress conditions. In addition, the wear resistance and corrosion resistance of these traditional coatings are also difficult to meet the requirements in extreme space environments. Therefore, it is necessary to develop a new titanium alloy surface coating technology to improve its performance in space environments, especially in terms of wear resistance, corrosion resistance and adhesion. Summary of the invention

[0003] The present invention provides a high-performance titanium alloy coating for use in a space environment and a preparation method thereof, aiming to solve the problems of insufficient wear resistance, corrosion resistance and adhesion of traditional coatings of titanium alloy materials in extreme space environments.

[0004] The present invention provides a high-performance titanium alloy coating for use in a space environment, comprising a substrate, wherein the substrate is a Ti-6Al-4V titanium alloy material, and a chromium bonding layer, a Ti / TiN gradient layer, a main structural layer of alternately arranged TiAlN-CrN, and an external functional layer of diamond-like carbon (DLC) are sequentially arranged on the substrate.

[0005] The present invention also provides a method for preparing the above-mentioned high-performance titanium alloy coating, comprising the following steps:

[0006] S1. Surface treatment: The surface of the substrate is subjected to gas etching treatment for 15-25 minutes, and the gas used is argon (Ar) or other inert gases (such as He, Ne, etc.);

[0007] S2. Place the surface treated substrate into a PVD coating device to prepare a chromium bonding layer, a Ti / TiN gradient layer, and a main structure layer of TiAlN-CrN alternately arranged, and take out the substrate;

[0008] S3. Place the substrate into a PECVD coating device to prepare an external functional layer of DLC.

[0009] Furthermore, the thickness of the chromium adhesion layer is 0.05-0.1 μm.

[0010] Furthermore, the thickness of the Ti / TiN gradient layer is 1-2 μm.

[0011] Furthermore, the thickness of the main structural layer of TiAlN-CrN alternately arranged is 2-3 μm.

[0012] Furthermore, the thickness of the outer functional layer of DLC is 1-2 μm.

[0013] Furthermore, before step S1, the process also includes: cleaning the surface of the Ti-6Al-4V titanium alloy substrate with ionized water to remove dust and impurities on the surface, then placing it in an isopropanol solution with a volume concentration of 5%, further cleaning to remove organic impurities on the surface, and then drying it.

[0014] Furthermore, the specific operation of step S2 is: introducing the substrate into a target coating chamber equipped with a chromium bonding layer, turning on a pump to evacuate and a heating device to heat the substrate, so that the background vacuum reaches 0.5-1.5 Pa, and after reaching a process temperature of 200-500° C., 10-1000 sccm of process gas is introduced into the chamber, and then a sputtering power source is started, and a sputtering power of 1-15 KW is set to obtain a chromium bonding layer;

[0015] Then, the substrate plated with the chromium bonding layer is introduced into a coating chamber containing a target material for forming a Ti / TiN gradient layer, heated to a process temperature of 200-500°C, a process gas is introduced into the chamber, and a sputtering power of 1-15KW is set to obtain a Ti / TiN gradient layer;

[0016] The substrate coated with the Ti / TiN gradient layer is then introduced into a target coating chamber equipped with a main structure layer of TiAlN-CrN alternately arranged, heated to a process temperature of 200-500°C, a process gas is introduced into the chamber, and a sputtering power of 1-15KW is set to obtain a main structure layer of TiAlN-CrN alternately arranged.

[0017] Furthermore, the process gas is at least one of Ar, N2, and O2, wherein the Ar gas flow rate is 10-1000sccm, the N2 gas flow rate is 10-1000sccm, and the O2 gas flow rate is 10-1000sccm.

[0018] Furthermore, the specific operations of step S3 are:

[0019] 1) Place the substrate on the rotatable target table in the PECVD coating equipment and use the vacuum system to evacuate to 5.0×10 -3 Pa, introduce Ar, start RF to perform Ar plasma sputtering cleaning on the sample;

[0020] 2) C2H2 (or CH4 or C3H8), Ar and N2 are introduced into the reaction chamber, the flow ratio is controlled to be 3:4-6:1-2, the bias voltage is adjusted to -1000--600V, the duty cycle is controlled to be 20-30%, the pulse frequency is 1200-1500Hz, the gas pressure is maintained at 0.5-1.5Pa, the deposition time is 30-40min, and the external functional layer of DLC is obtained on the surface of the substrate.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention provides a high-performance titanium alloy coating for use in a space environment and a preparation method thereof, wherein the coating comprises a chromium bonding layer, a Ti / TiN gradient layer, a main structural layer of TiAlN-CrN alternatingly arranged, and an external functional layer of diamond-like carbon (DLC) arranged in sequence, wherein the main structural layer of TiAlN-CrN alternatingly arranged is a nano-layered structure, which can not only significantly improve the thermal stability of the coating, so that it can be used in a space environment with extreme temperature changes (such as the moon); and this nano-layered structure can neutralize the difference in thermal expansion coefficients of different materials in other layers, reduce the internal stress caused by temperature changes, and thus improve the overall thermal shock resistance; moreover, this nano-layered structure can also improve the ability to resist crack propagation, thereby improving the overall durability of the coating, and enhancing the mechanical properties and wear resistance;

[0023] (2) The coating of the present invention also combines a material with a higher hardness (such as TiAlN) with a material with good toughness (such as CrN), which can achieve a better balance between hardness and toughness. This combination is more resistant to wear and impact than a single material; the outer functional layer of diamond-like carbon (DLC) in the coating of the present invention provides a low friction coefficient, which not only provides continuous low friction characteristics, but also maintains good lubricity under extreme conditions (such as vacuum and high radiation environments);

[0024] (3) The coating of the present invention includes adjacent bonding layers (such as chromium or nickel) and gradient layers (such as Ti / TiN), which can significantly improve the bonding strength between the layers and ensure the stability and durability of the coating under extreme environments; the introduction of the gradient layer also helps to smooth the differences in thermal and mechanical properties between the layers, thereby improving the stability of the overall structure;

[0025] (4) The coating of the present invention combines materials with different anti-corrosion properties (such as CrN and DLC) to provide more comprehensive protection, allowing it to maintain long-lasting good performance in space environments with extreme temperature changes (such as the moon), especially when exposed to solar radiation and particle impact. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The present invention is specifically introduced below in conjunction with the specific embodiments.

[0027] An embodiment of the present invention provides a high-performance titanium alloy coating for use in a space environment, comprising a substrate, wherein the substrate is a Ti-6Al-4V titanium alloy material, and a chromium bonding layer, a Ti / TiN gradient layer, a main structural layer of alternating TiAlN-CrN, and an external functional layer of DLC are sequentially arranged on the substrate.

[0028] The present invention also provides a method for preparing the above-mentioned high-performance titanium alloy coating, comprising the following steps:

[0029] S1. Surface treatment: The surface of the substrate is subjected to gas etching treatment, the etching time is 15-25 minutes, preferably 20 minutes, and the gas used is argon (Ar) or other inert gas to clean the surface of the material and increase the roughness to improve the adhesion of the subsequent coating;

[0030] S2. Place the surface-treated substrate into a PVD coating device to prepare a chromium bonding layer, a Ti / TiN gradient layer (composition: gradually transitioning from pure titanium to titanium nitride) and a main structural layer of TiAlN-CrN alternating arrangement, and take out the substrate; wherein, the chromium bonding layer is used to enhance the adhesion between the substrate and the subsequent coating; the Ti / TiN gradient layer provides a smooth transition from the softer base layer to the harder outer layer, reduces internal stress, and improves the overall integrity of the coating; the main structural layer of TiAlN-CrN alternating arrangement is a nano-layered structure, which can enhance toughness and resistance to crack propagation.

[0031] S3. Place the substrate into a PECVD coating device to prepare an external functional layer of DLC. The external functional layer of DLC has an extremely low friction coefficient and high hardness, which further improves the wear resistance and environmental corrosion resistance of the material.

[0032] Specifically, the thickness of the chromium adhesion layer is 0.05-0.1 μm.

[0033] Specifically, the thickness of the Ti / TiN gradient layer is 1-2 μm.

[0034] Specifically, the thickness of the main structure layer of TiAlN-CrN alternately arranged is 2-3 μm.

[0035] Specifically, the thickness of the outer functional layer of DLC is 1-2 μm.

[0036] Specifically, before step S1, the process also includes: cleaning the surface of the Ti-6Al-4V titanium alloy substrate with ionized water to remove dust and impurities on the surface, then placing it in an isopropanol solution with a volume concentration of 5%, further cleaning to remove organic impurities on the surface, and then drying it.

[0037] Specifically, the specific operation of step S2 is: introducing the substrate into a target coating chamber equipped with a chromium bonding layer, turning on a pump to evacuate and a heating device to heat the substrate, so that the background vacuum reaches 0.5-1.5 Pa, and after reaching a process temperature of 200-500° C., 10-1000 sccm of process gas is introduced into the chamber, and then a sputtering power source is started, and a sputtering power of 1-15 KW is set to obtain a chromium bonding layer;

[0038] Then, the substrate plated with the chromium bonding layer is introduced into a coating chamber containing a target material for forming a Ti / TiN gradient layer, heated to a process temperature of 200-500°C, a process gas is introduced into the chamber, and a sputtering power of 1-15KW is set to obtain a Ti / TiN gradient layer;

[0039] The substrate coated with the Ti / TiN gradient layer is then introduced into a target coating chamber equipped with a main structure layer of TiAlN-CrN alternately arranged, heated to a process temperature of 200-500°C, a process gas is introduced into the chamber, and a sputtering power of 1-15KW is set to obtain a main structure layer of TiAlN-CrN alternately arranged.

[0040] Specifically, the process gas is at least one of Ar, N2, and O2, wherein the Ar gas flow rate is 10-1000sccm, the N2 gas flow rate is 10-1000sccm, and the O2 gas flow rate is 10-1000sccm.

[0041] Specifically, the specific operations of step S3 are:

[0042] 1) Place the substrate on the rotatable target table in the PECVD coating equipment and use the vacuum system to evacuate to 5.0×10 -3 Pa, introduce Ar, start RF to perform Ar plasma sputtering cleaning on the sample;

[0043] 2) C2H2 (or CH4 or C3H8), Ar and N2 are introduced into the reaction chamber, the flow ratio is controlled to be 3:4-6:1-2, the bias voltage is adjusted to -1000--600V, the duty cycle is controlled to be 20-30%, the pulse frequency is 1200-1500Hz, the gas pressure is maintained at 0.5-1.5Pa, the deposition time is 30-40min, and the external functional layer of DLC is obtained on the surface of the substrate.

[0044] Example 1

[0045] The chromium bonding layer, the Ti / TiN gradient layer, the main structural layer of TiAlN-CrN alternating arrangement and the DLC outer functional layer were prepared on the Ti-6Al-4V titanium alloy substrate according to the following steps:

[0046] (1) The surface of the Ti-6Al-4V titanium alloy substrate was cleaned with ionized water to remove dust and impurities on the surface, and then placed in an isopropanol solution with a volume concentration of 5%, and further cleaned to remove organic impurities on the surface, and then blown dry.

[0047] (2) Surface treatment: The surface of the substrate is subjected to gas etching treatment for 15 minutes using argon (Ar) gas;

[0048] (3) The substrate is introduced into a coating chamber containing a target material capable of forming a chromium bonding layer, and a vacuum pump and a heating device are turned on to heat the substrate, so that the background vacuum reaches 1.5 Pa and the process temperature reaches 200° C., and then 1000 sccm of process gas is introduced into the chamber, and then a sputtering power source is started, and the sputtering power is set to 1 kW to obtain a chromium bonding layer;

[0049] (4) The substrate after the chromium bonding layer is plated is introduced into a coating chamber containing a target material capable of forming a Ti / TiN gradient layer, heated to a process temperature of 500° C., a process gas is introduced into the chamber, and a sputtering power of 1 KW is set to obtain a Ti / TiN gradient layer;

[0050] (5) The substrate coated with the Ti / TiN gradient layer is then introduced into a target coating chamber equipped with a main structure layer of TiAlN-CrN alternately arranged, heated to a process temperature of 500° C., a process gas is introduced into the chamber, and a sputtering power of 1 KW is set to obtain a main structure layer of TiAlN-CrN alternately arranged;

[0051] (6) Place the substrate on the rotatable target table in the PECVD coating equipment and use the vacuum system to evacuate the vacuum to 5.0×10 -3 Pa, introduce Ar, start RF to perform Ar plasma sputtering cleaning on the sample;

[0052] (7) C2H2, Ar and N2 are introduced into the reaction chamber, the flow ratio is controlled to be 3:4:2, the bias voltage is adjusted to -600 V, the duty cycle is controlled to be 20%, the pulse frequency is 1500 Hz, the gas pressure is maintained at 0.5 Pa, the deposition time is 40 min, and an external functional layer of DLC is obtained on the surface of the substrate.

[0053] The high-performance titanium alloy coating prepared in this embodiment was tested at extreme temperatures (-173°C, 127°C) and room temperature. When the coating was subjected to a scratch load of 120N, no significant cracks or peeling occurred. The friction coefficient was 0.08 at room temperature of 25°C, 0.11 at -173°C, and 0.10 at 127°C. According to the VD13198 standard, the adhesion test of the coating prepared in this embodiment reached the HF1 standard.

[0054] Example 2

[0055] The chromium bonding layer, the Ti / TiN gradient layer, the main structural layer of TiAlN-CrN alternating arrangement and the DLC outer functional layer were prepared on the Ti-6Al-4V titanium alloy substrate according to the following steps:

[0056] (1) The surface of the Ti-6Al-4V titanium alloy substrate was cleaned with ionized water to remove dust and impurities on the surface, and then placed in an isopropanol solution with a volume concentration of 5%, and further cleaned to remove organic impurities on the surface, and then blown dry.

[0057] (2) Surface treatment: The surface of the substrate is subjected to gas etching treatment for 25 minutes using argon (Ar) gas;

[0058] (3) The substrate is introduced into a coating chamber containing a target material capable of forming a chromium bonding layer, and a vacuum pump and a heating device are turned on to heat the substrate, so that the background vacuum reaches 0.5 Pa and the process temperature reaches 500° C., and then 10 sccm of process gas is introduced into the chamber, and then a sputtering power source is started, and the sputtering power is set to 15 kW to obtain a chromium bonding layer;

[0059] (4) The substrate after the chromium bonding layer is plated is introduced into a coating chamber containing a target material capable of forming a Ti / TiN gradient layer, heated to a process temperature of 200° C., a process gas is introduced into the chamber, and a sputtering power of 15 KW is set to obtain a Ti / TiN gradient layer;

[0060] (5) The substrate coated with the Ti / TiN gradient layer is then introduced into a target coating chamber equipped with a main structure layer of TiAlN-CrN alternately arranged, heated to a process temperature of 200° C., a process gas is introduced into the chamber, and a sputtering power of 15 KW is set to obtain a main structure layer of TiAlN-CrN alternately arranged;

[0061] (6) Place the substrate on the rotatable target table in the PECVD coating equipment and use the vacuum system to evacuate the vacuum to 5.0×10 -3 Pa, introduce Ar, start RF to perform Ar plasma sputtering cleaning on the sample;

[0062] (7) CH4, Ar and N2 were introduced into the reaction chamber, the flow ratio was controlled to be 3:6:1, the bias voltage was adjusted to -1000 V, the duty cycle was controlled to be 30%, the pulse frequency was 1200 Hz, the gas pressure was maintained at 1.5 Pa, the deposition time was 30 min, and an external functional layer of DLC was obtained on the surface of the substrate.

[0063] The high-performance titanium alloy coating prepared in this embodiment was tested at extreme temperatures (-173°C, 127°C) and room temperature. When the coating was subjected to a scratch load of 120N, no significant cracks or peeling occurred. The friction coefficient was 0.10 at room temperature of 25°C, 0.13 at -173°C, and 0.12 at 127°C. According to the VD13198 standard, the adhesion test of the coating prepared in this embodiment reached the HF1 standard.

[0064] Example 3

[0065] The chromium bonding layer, the Ti / TiN gradient layer, the main structural layer of TiAlN-CrN alternating arrangement and the DLC outer functional layer were prepared on the Ti-6Al-4V titanium alloy substrate according to the following steps:

[0066] (1) The surface of the Ti-6Al-4V titanium alloy substrate was cleaned with ionized water to remove dust and impurities on the surface, and then placed in an isopropanol solution with a volume concentration of 5%, and further cleaned to remove organic impurities on the surface, and then blown dry.

[0067] (2) Surface treatment: The surface of the substrate is subjected to gas etching treatment for 20 minutes, and the gas used is argon (Ar) or other inert gas;

[0068] (3) The substrate is introduced into a coating chamber containing a target material capable of forming a chromium bonding layer, and a vacuum pump and a heating device are turned on to heat the substrate, so that the background vacuum reaches 1.0 Pa and the process temperature reaches 350° C., and then 500 sccm of process gas is introduced into the chamber, and then a sputtering power source is started, and the sputtering power is set to 8 kW to obtain a chromium bonding layer;

[0069] (4) The substrate after the chromium bonding layer is plated is introduced into a coating chamber equipped with a target material for forming a Ti / TiN gradient layer, heated to a process temperature of 350° C., a process gas is introduced into the chamber, and a sputtering power is set to 8 kW to obtain a Ti / TiN gradient layer;

[0070] (5) The substrate coated with the Ti / TiN gradient layer is then introduced into a target coating chamber equipped with a main structure layer of TiAlN-CrN alternately arranged, heated to a process temperature of 350° C., a process gas is introduced into the chamber, and a sputtering power of 8 kW is set to obtain a main structure layer of TiAlN-CrN alternately arranged;

[0071] (6) Place the substrate on the rotatable target table in the PECVD coating equipment and use the vacuum system to evacuate the vacuum to 5.0×10 -3 Pa, introduce Ar, start RF to perform Ar plasma sputtering cleaning on the sample;

[0072] (7) C3H8, Ar and N2 were introduced into the reaction chamber, the flow ratio was controlled to be 3:5:1.5, the bias voltage was adjusted to -800 V, the duty cycle was controlled to be 25%, the pulse frequency was controlled to be 1350 Hz, the gas pressure was maintained at 1.0 Pa, the deposition time was 35 min, and an external functional layer of DLC was obtained on the surface of the substrate.

[0073] The high-performance titanium alloy coating prepared in this embodiment was tested at extreme temperatures (-173°C, 127°C) and room temperature. When the coating was subjected to a scratch load of 120N, no significant cracks or peeling occurred. The friction coefficient was 0.09 at room temperature of 25°C, 0.12 at -173°C, and 0.13 at 127°C. According to the VD13198 standard, the adhesion test of the coating prepared in this embodiment reached the HF1 standard.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-performance titanium alloy coating for use in a space environment, comprising a substrate, characterized in that: The substrate is a Ti-6Al-4V titanium alloy material, and a chromium bonding layer, a Ti / TiN gradient layer, a main structural layer of TiAlN-CrN alternately arranged, and a DLC external functional layer are sequentially arranged on the substrate, wherein the Ti / TiN gradient layer gradually transitions from pure titanium to titanium nitride, and the main structural layer of TiAlN-CrN alternately arranged has a nano-layered structure. The thickness of the chromium bonding layer is 0.05-0.1µm. The thickness of the Ti / TiN gradient layer is 1-2 μm. The thickness of the main structural layer of TiAlN-CrN alternately arranged is 2-3µm. The thickness of the outer functional layer of DLC is 1-2 μm.

2. A method for preparing a high-performance titanium alloy coating for use in a space environment as claimed in claim 1, characterized in that: The following steps are involved: S1. Surface treatment: The surface of the substrate is subjected to gas etching treatment, the etching time is 15-25 minutes, and the gas used is argon; S2. placing the surface treated substrate into a PVD coating device to prepare a chromium bonding layer, a Ti / TiN gradient layer, and a main structure layer of TiAlN-CrN alternating arrangement; S3. Place the substrate into a PECVD coating device to prepare an external functional layer of DLC.

3. The preparation method according to claim 2, characterized in that: Before step S1, the method further includes: cleaning the surface of the substrate, and then placing the substrate in an isopropanol solution with a volume concentration of 5% for further cleaning.

4. The preparation method according to claim 2, characterized in that: The specific operation of step S2 is: introducing the substrate into a target coating chamber equipped with a chromium bonding layer, turning on a pump to evacuate and a heating device to heat the substrate, so that the background vacuum reaches 0.5-1.5 Pa, and after reaching a process temperature of 200-500° C., 10-1000 sccm of process gas is introduced into the chamber, and then a sputtering power source is started, and a sputtering power of 1-15 kW is set to obtain a chromium bonding layer; Then, the substrate plated with the chromium bonding layer is introduced into a coating chamber containing a target material for forming a Ti / TiN gradient layer, heated to a process temperature of 200-500°C, a process gas is introduced into the chamber, and a sputtering power of 1-15kW is set to obtain a Ti / TiN gradient layer; The substrate coated with the Ti / TiN gradient layer is then introduced into a target coating chamber equipped with a main structure layer of TiAlN-CrN alternately arranged, heated to a process temperature of 200-500°C, a process gas is introduced into the chamber, and a sputtering power of 1-15kW is set to obtain a main structure layer of TiAlN-CrN alternately arranged.

5. The preparation method according to claim 4, characterized in that: The process gas is at least one of Ar, N2, and O2, wherein the Ar gas flow rate is 10-1000sccm, the N2 gas flow rate is 10-1000sccm, and the O2 gas flow rate is 10-1000sccm.

6. The preparation method according to claim 2, characterized in that: The specific operations of step S3 are: 1) Place the substrate on the rotatable target table in the PECVD coating equipment and use the vacuum system to evacuate to 5.0×10 -3 Pa, introduce Ar, start RF to perform Ar plasma sputtering cleaning on the sample; 2) Introduce C2H2, Ar and N2 into the reaction chamber, control the flow ratio to 3:4-6:1-2, adjust the bias voltage to -1000-600V, control the duty cycle to 20-30%, the pulse frequency to 1200-1500Hz, maintain the gas pressure to 0.5-1.5Pa, and the deposition time to 30-40min to obtain an external functional layer of DLC on the substrate surface.