A wear-resistant lubricating composite structure film for space and a preparation method thereof

Abstract

The application provides a space wear-resistant lubricating composite structure film and a preparation method thereof, and relates to the field of vacuum solid lubrication. The space wear-resistant lubricating composite structure film comprises a metal transition layer, a gradient transition layer, an a-C layer, a ta-C layer and an a-C:H layer which are sequentially arranged on a metal base. The low-stress a-C layer, the high-hardness ta-C layer and the high-lubricating a-C:H layer are organically combined, and the connection transition between the metal base and the layers is realized through the Ti transition layer and the Ti / C gradient transition layer. The a-C layer reduces the internal stress of the film, improves the film base bonding force, the high-hardness ta-C film is used, the wear resistance of the film is enhanced, and the a-C:H layer has excellent vacuum lubricating performance. That is, the composite structure film has high hardness, high bonding force and excellent vacuum tribological performance, so that the film can meet the long-life operation requirement of space moving parts.

Description

Technical Field

[0001] This invention relates to the field of vacuum solid lubrication, and more specifically to a wear-resistant lubricating composite thin film for space applications and its preparation method. Background Technology

[0002] Spacecraft operate in a vacuum environment, and the lubrication of their space mechanisms typically employs grease or solid lubrication. Grease lubrication is prone to evaporation in space and has a narrow operating temperature range. Compared to lubricating oil or grease, solid lubrication films are more suitable for low-speed, high-precision, and structurally complex components. Traditional MoS2 films have been widely used in space lubrication, but their low hardness makes them prone to wear during service, resulting in a short frictional life. However, from the perspective of material tribological behavior, designing and fabricating a film that combines excellent wear resistance and solid lubrication properties is extremely challenging.

[0003] Therefore, how to design a wear-resistant and lubricating composite membrane for space applications that combines lubrication and wear resistance to meet the lubrication needs of long-life moving parts in space has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the solid lubricating film of the space moving mechanism in the prior art, which has low hardness and is easy to wear during service, resulting in a short friction life. The present invention provides a space wear-resistant lubricating composite structure film with both lubrication and wear resistance properties, which meets the lubrication requirements of long-life space moving parts, and the preparation method thereof.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a wear-resistant and lubricating composite thin film for space use, comprising a metal transition layer, a gradient transition layer, an aC layer, a ta-C layer and an aC:H layer sequentially stacked on a metal substrate.

[0007] Furthermore, the metal transition layer includes a Ti transition layer.

[0008] Furthermore, the gradient transition layer includes a Ti / C transition layer.

[0009] Furthermore, the thickness of the metal transition layer is 50–70 nm.

[0010] Furthermore, the thickness of the gradient transition layer is 50–70 nm.

[0011] Furthermore, the thickness of the aC layer is 100–150 nm.

[0012] Furthermore, the thickness of the ta-C layer is 200–300 nm.

[0013] Furthermore, the thickness of the aC:H layer is 500–600 nm.

[0014] Furthermore, the metal matrix material includes at least one of stainless steel, high-speed steel, and bearing steel.

[0015] Secondly, the present invention provides a method for preparing the aforementioned wear-resistant and lubricating composite thin film for space use, comprising: sequentially preparing a metal transition layer, a gradient transition layer, an aC layer, a ta-C layer and an aC:H layer on a metal substrate, wherein the metal transition layer, the gradient transition layer, the aC layer and the aC:H layer are prepared using high-power magnetron sputtering technology, and the ta-C layer is prepared using electromagnetically controlled cathode arc technology.

[0016] High-power magnetron sputtering technology and electromagnetically controlled cathode arc technology are both existing technologies, and the corresponding film layers can be prepared by adjusting the process parameters according to the requirements.

[0017] The technical solution of this invention has the following advantages:

[0018] This invention provides a wear-resistant and lubricating composite thin film for space applications, comprising a metal transition layer, a gradient transition layer, an aC layer, a ta-C layer, and an aC:H layer sequentially stacked on a metal substrate. The low-stress aC layer, the high-hardness ta-C layer, and the high-lubricity aC:H layer are organically combined, and the connection between the film and the metal substrate is achieved through a Ti transition layer and a Ti / C gradient transition layer. This approach reduces internal stress in the film and enhances the film-substrate adhesion based on the aC layer, leverages the high hardness of the ta-C layer to improve wear resistance, and also possesses the excellent vacuum lubrication performance of the aC:H layer. In other words, this composite thin film simultaneously exhibits high hardness, high adhesion, and excellent vacuum tribological properties, enabling it to meet the requirements for long-life operation of space-moving components. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the space wear-resistant and lubricating composite thin film provided in the embodiment of the present invention;

[0021] Figure 2This is a schematic diagram of the equipment used to prepare a wear-resistant and lubricating composite thin film for space applications in this embodiment of the invention.

[0022] Figure label:

[0023] 1-Metal substrate; 2-Metal transition layer; 3-Gradient transition layer; 4-aC layer; 5-ta-C layer; 6-aC:H layer; 7-Workpiece stage; 8-High-power magnetron sputtering Ti target; 9-High-power magnetron sputtering graphite target; 10-Electromagnetically controllable cathode arc graphite target; 11-Anode layer ion source. Detailed Implementation

[0024] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0025] The structure of the space wear-resistant and lubricating composite thin film obtained by the preparation method provided by the present invention is as follows: Figure 1 As shown, a metal transition layer 2, a gradient transition layer 3, an aC layer 4, a ta-C layer 5, and an aC:H layer 6 are sequentially deposited on the surface of a metal substrate 1. In the following embodiments, the metal transition layer 2 is specifically a Ti transition layer, and the gradient transition layer 3 is specifically a Ti / C gradient transition layer.

[0026] This invention employs specific equipment to prepare wear-resistant and lubricating composite thin films for space applications, such as... Figure 2 As shown, the preparation process is carried out in a vacuum furnace. A workpiece stage 7 is set in the center of the vacuum furnace to fix the material to be processed. The vacuum furnace has 8 sides, on which are arranged high-power magnetron sputtering Ti target 8 (for depositing Ti transition layer and Ti / C gradient transition layer), high-power magnetron sputtering graphite target 9 (for depositing aC layer and aC:H layer), electromagnetically controllable cathode arc graphite target 10 (for depositing ta-C layer) and anode layer ion source 11 (for cleaning metal substrate).

[0027] Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. All raw materials or instruments used are commercially available conventional products, including but not limited to those used in the embodiments of this application.

[0028] Example 1

[0029] This embodiment describes the preparation of a space-use wear-resistant and lubricating composite thin film on the surface of a 9Cr18 stainless steel substrate. The specific steps are as follows:

[0030] (1) Pretreatment of the metal matrix:

[0031] Select a 9Cr18 stainless steel substrate, first grind and polish the stainless steel substrate to make its surface roughness less than Ra0.8, then place it in acetone solution for ultrasonic cleaning for 10 min, then clean it in alcohol solution for 10 min, and then dry it in a drying oven at 70℃ for 20 min.

[0032] The cleaned and dried substrate is placed into the vacuum furnace chamber and fixed on the workpiece holder 7. Then, a vacuum is drawn to ensure that the vacuum level in the vacuum furnace chamber is better than 1×10⁻⁶. -3 Pa, and heat the vacuum furnace cavity to 70-90℃;

[0033] The anode layer ion source was turned on to bombard the substrate surface to remove impurities. The anode layer ion beam source voltage was 1200V. Argon gas was introduced into the vacuum furnace cavity, the vacuum degree of the cavity was 0.5Pa, a bias voltage of -500V was applied to the substrate, and the cleaning time was 30min.

[0034] (2) Deposition of Ti transition layer:

[0035] Argon gas was introduced into the vacuum furnace chamber at a pressure of 0.8 Pa. High-power pulsed magnetron sputtering was performed on a high-power magnetron sputtering Ti target 8 with a voltage of 600-650 V, an average target power of 6 kW, a substrate bias of -100 V, and a deposition time of 10 min, resulting in a Ti transition layer with a thickness of 56 nm.

[0036] (3) Deposition of Ti / C gradient transition layer:

[0037] With the argon flow rate kept constant, acetylene (C2H2) gas was introduced into the vacuum furnace chamber. The gas flow rate was gradually increased from 0 to 100 sccm. The Ti target discharge parameters remained constant, the substrate bias voltage was -100V, and the deposition time was 10 min. The resulting Ti / C gradient transition layer had a thickness of 62 nm.

[0038] (4) Deposition of the aC layer:

[0039] Argon gas was introduced into the vacuum furnace chamber at a pressure of 0.8 Pa. High-power pulsed magnetron sputtering was performed on the high-power magnetron sputtering graphite target 9 with a voltage of 900–1100 V, a substrate bias of -70 V, an average target power of 1 kW, and a deposition time of 20 min, resulting in an aC layer with a thickness of 124 nm.

[0040] (5) Deposition of the ta-C layer:

[0041] Stop the argon gas input and wait for the vacuum level in the vacuum furnace chamber to be better than 3×10⁻⁶. -3Pa, the electromagnetic controllable cathode arc graphite target 10 is turned on, the graphite target voltage is 250V, the substrate bias voltage is -80V, the deposition time is 30min, and the thickness of the ta-C layer is 220nm.

[0042] (6) Deposition of aC:H layer:

[0043] Argon and acetylene gases were introduced into the vacuum furnace chamber at a flow rate of 40 sccm and 40 sccm, respectively, at a pressure of 1 Pa. High-power pulsed magnetron sputtering was performed on a high-power magnetron sputtering graphite target 9 with a voltage of 900–1100 V, an average target power of 1 kW, a substrate bias of -50 V, and a deposition time of 60 min, resulting in an aC:H layer with a thickness of 550 nm.

[0044] (7) Take out:

[0045] Stop the coating process until the temperature of the vacuum furnace chamber is below 80°C, then remove the substrate to obtain a space-use wear-resistant and lubricating composite thin film.

[0046] The prepared wear-resistant and lubricating composite thin film for space applications was characterized by testing. The total thickness of the film was 1.01 μm, the hardness of the nanoindentation test was 32 GPa, the film-substrate adhesion test was greater than 400 mN, the coefficient of friction under vacuum was less than 0.05, and the wear rate was 2.1 × 10⁻⁶. 16 m 3 / (N·m).

[0047] Example 2

[0048] This embodiment describes the preparation of a wear-resistant and lubricating composite thin film for space applications on the surface of a cemented carbide substrate. The specific steps are as follows:

[0049] (1) Pretreatment of the metal matrix:

[0050] Select a cemented carbide substrate of a certain size. First, grind and polish the cemented carbide substrate to make its surface roughness less than Ra0.8. Then, place it in an acetone solution for ultrasonic cleaning for 10 minutes, then clean it in an alcohol solution for 10 minutes, and then dry it in a drying oven at a temperature of 70℃ for 20 minutes.

[0051] The cleaned and dried substrate is placed into the vacuum furnace chamber and fixed on the workpiece holder 7. Then, a vacuum is drawn to ensure that the vacuum level in the vacuum furnace chamber is better than 1×10⁻⁶. -3 Pa, and heat the vacuum furnace cavity to 70-90℃;

[0052] The anode layer ion source was turned on to bombard the substrate surface to remove impurities. The anode layer ion beam source voltage was 1200V. Argon gas was introduced into the vacuum furnace cavity, the vacuum degree of the cavity was 0.5Pa, a bias voltage of -500V was applied to the substrate, and the cleaning time was 30min.

[0053] (2) Deposition of Ti transition layer:

[0054] Argon gas was introduced into the vacuum furnace chamber at a pressure of 0.8 Pa. High-power pulsed magnetron sputtering was performed on a high-power magnetron sputtering Ti target 8 with a voltage of 600-650 V, an average target power of 1 kW, a substrate bias of -100 V, and a deposition time of 10 min, resulting in a Ti transition layer with a thickness of 58 nm.

[0055] (3) Deposition of Ti / C gradient transition layer:

[0056] With the argon flow rate kept constant, acetylene (C2H2) gas was introduced into the vacuum furnace chamber. The gas flow rate was gradually increased from 0 to 100 sccm. The Ti target discharge parameters remained unchanged, the substrate bias voltage was -100V, and the deposition time was 10 min. A Ti / C gradient transition layer with a thickness of 65 nm was obtained.

[0057] (4) Deposition of the aC layer:

[0058] Argon gas was introduced into the vacuum furnace chamber at a pressure of 0.8 Pa. High-power pulsed magnetron sputtering was performed on the high-power magnetron sputtering graphite target 9 with a voltage of 900–1100 V, a substrate bias of -70 V, an average target power of 1 kW, and a deposition time of 20 min, resulting in an aC layer with a thickness of 130 nm.

[0059] (5) Deposition of the ta-C layer:

[0060] Stop the argon gas input and wait for the vacuum level in the vacuum furnace chamber to be better than 3×10⁻⁶. -3 Pa, the electromagnetic controllable cathode arc graphite target 10 is turned on, the graphite target voltage is 250V, the substrate bias voltage is -80V, the deposition time is 30min, and the thickness of the ta-C layer is 220nm.

[0061] (6) Deposition of aC:H layer:

[0062] Argon and acetylene gases were introduced into the vacuum furnace chamber at a flow rate of 40 sccm and 40 sccm, respectively, at a pressure of 1 Pa. High-power pulsed magnetron sputtering was performed on a high-power magnetron sputtering graphite target 9 with a voltage of 900–1100 V, an average target power of 1 kW, a substrate bias of -50 V, and a deposition time of 60 min, resulting in an aC:H layer with a thickness of 560 nm.

[0063] (7) Take out:

[0064] Stop the coating process until the temperature of the vacuum furnace chamber is below 80°C, then remove the substrate to obtain a space-use wear-resistant and lubricating composite thin film.

[0065] The prepared wear-resistant and lubricating composite thin film for space applications was characterized by testing. The total thickness of the film was 1.03 μm, the hardness of the nanoindentation test was 31 GPa, the film-substrate adhesion in the nanoscratching test was greater than 400 mN, the coefficient of friction under vacuum was less than 0.05, and the wear rate was 2.7 × 10⁻⁶. -16 m 3 / (N·m).

[0066] Example 3

[0067] This embodiment describes the preparation of a space-use wear-resistant and lubricating composite thin film on the surface of a high-speed steel substrate. The specific steps are as follows:

[0068] (1) Pretreatment of the metal matrix:

[0069] Select a high-speed steel substrate, grind and polish it to make its surface roughness less than Ra0.8, then place it in acetone solution for ultrasonic cleaning for 10 minutes, then clean it in alcohol solution for 10 minutes, and then dry it in a drying oven at 70℃ for 20 minutes.

[0070] The cleaned and dried substrate is placed into the vacuum furnace chamber and fixed on the workpiece holder 7. Then, a vacuum is drawn to ensure that the vacuum level in the vacuum furnace chamber is better than 1×10⁻⁶. -3 Pa, and heat the vacuum furnace cavity to 70-90℃;

[0071] The anode layer ion source was turned on to bombard the substrate surface to remove impurities. The anode layer ion beam source voltage was 1200V. Argon gas was introduced into the vacuum furnace cavity, the vacuum degree of the cavity was 0.5Pa, a bias voltage of -500V was applied to the substrate, and the cleaning time was 30min.

[0072] (2) Deposition of Ti transition layer:

[0073] Argon gas was introduced into the vacuum furnace chamber at a pressure of 0.8 Pa. High-power pulsed magnetron sputtering was performed on a high-power magnetron sputtering Ti target 8 with a voltage of 600-650 V, an average target power of 6 kW, a substrate bias of -100 V, and a deposition time of 10 min, resulting in a Ti transition layer with a thickness of 55 nm.

[0074] (3) Deposition of Ti / C gradient transition layer:

[0075] With the argon flow rate kept constant, acetylene (C2H2) gas was introduced into the vacuum furnace chamber. The gas flow rate was gradually increased from 0 to 100 sccm. The Ti target discharge parameters remained unchanged, the substrate bias voltage was -100V, and the deposition time was 10 min. The resulting Ti / C gradient transition layer had a thickness of 68 nm.

[0076] (4) Deposition of the aC layer:

[0077] Argon gas was introduced into the vacuum furnace chamber at a pressure of 0.8 Pa. High-power pulsed magnetron sputtering was performed on the high-power magnetron sputtering graphite target 9 with a voltage of 900–1100 V, a substrate bias of -70 V, an average target power of 1 kW, and a deposition time of 20 min, resulting in an aC layer with a thickness of 135 nm.

[0078] (5) Deposition of the ta-C layer:

[0079] Stop the argon gas input and wait for the vacuum level in the vacuum furnace chamber to be better than 3×10⁻⁶. -3 Pa, the electromagnetic controllable cathode arc graphite target 10 is turned on, the graphite target voltage is 250V, the substrate bias voltage is -80V, the deposition time is 30min, and the thickness of the ta-C layer is 220nm.

[0080] (6) Deposition of aC:H layer:

[0081] Argon and acetylene gases were introduced into the vacuum furnace chamber at a flow rate of 40 sccm and 40 sccm, respectively, at a pressure of 1 Pa. High-power pulsed magnetron sputtering was performed on a high-power magnetron sputtering graphite target 9 with a voltage of 900–1100 V, an average target power of 1 kW, a substrate bias of -50 V, and a deposition time of 60 min, resulting in an aC:H layer with a thickness of 580 nm.

[0082] (7) Take out:

[0083] Stop the coating process until the temperature of the vacuum furnace chamber is below 80°C, then remove the substrate to obtain a space-use wear-resistant and lubricating composite thin film.

[0084] The prepared wear-resistant and lubricating composite thin film for space applications was characterized by testing. The total thickness of the film was 1.05 μm. The hardness of the nanoindentation test was 32 GPa, the film-substrate adhesion test was greater than 400 mN, the coefficient of friction under vacuum was less than 0.05, and the wear rate was 2.5 × 10⁻⁶. -16 m 3 / (N·m).

[0085] Comparative Example

[0086] This comparative example demonstrates the preparation of a space-grade aC:H lubricating film on the surface of a 9Cr18 stainless steel substrate. The specific steps are as follows:

[0087] (1) Pretreatment of the metal matrix:

[0088] Select a high-speed steel substrate, grind and polish it to make its surface roughness less than Ra0.8, then place it in acetone solution for ultrasonic cleaning for 10 minutes, then clean it in alcohol solution for 10 minutes, and then dry it in a drying oven at 70℃ for 20 minutes.

[0089] The cleaned and dried substrate is placed into the vacuum furnace chamber and fixed on the workpiece holder 7. Then, a vacuum is drawn to ensure that the vacuum level in the vacuum furnace chamber is better than 1×10⁻⁶. -3 Pa, and heat the vacuum furnace cavity to 70-90℃;

[0090] The anode layer ion source was turned on to bombard the substrate surface to remove impurities. The anode layer ion beam source voltage was 1200V. Argon gas was introduced into the vacuum furnace cavity, the vacuum degree of the cavity was 0.5Pa, a bias voltage of -500V was applied to the substrate, and the cleaning time was 30min.

[0091] (2) Deposition of Ti transition layer:

[0092] Argon gas was introduced into the vacuum furnace chamber at a pressure of 0.8 Pa. High-power pulsed magnetron sputtering was performed on a high-power magnetron sputtering Ti target 8 with a voltage of 600-650 V, an average target power of 6 kW, a substrate bias of -100 V, and a deposition time of 10 min, resulting in a Ti transition layer with a thickness of 55 nm.

[0093] (3) Deposition of Ti / C gradient transition layer:

[0094] With the argon flow rate kept constant, acetylene (C2H2) gas was introduced into the vacuum furnace chamber. The gas flow rate was gradually increased from 0 to 100 sccm. The Ti target discharge parameters remained unchanged, the substrate bias voltage was -100V, and the deposition time was 10 min. The resulting Ti / C gradient transition layer had a thickness of 68 nm.

[0095] (4) Deposition of aC:H layer:

[0096] Argon and acetylene gases were introduced into the vacuum furnace chamber at a flow rate of 40 sccm and 40 sccm, respectively, with a pressure of 1 Pa. High-power pulsed magnetron sputtering was performed on a high-power magnetron sputtering graphite target 9 with a voltage of 900–1100 V, an average target power of 1 kW, a substrate bias of -50 V, and a deposition time of 90 min, resulting in an aC:H layer with a thickness of 870 nm.

[0097] (5) Take it out:

[0098] Stop the coating process until the temperature of the vacuum furnace chamber is below 80°C, then remove the substrate to obtain a space-use wear-resistant and lubricating composite thin film.

[0099] The prepared aC:H lubricating thin film for space use was characterized by testing. The total thickness of the wear-resistant lubricating composite film for space use was 993 nm. The hardness of the nanoindentation test was 3.6 GPa, the film-substrate adhesion test was greater than 400 mN, the coefficient of friction under vacuum was less than 0.02, and the wear rate was 8.4 × 10⁻⁶. -16 m 3 / (N·m).

[0100] In contrast, while the single-structure aC:H lubricating film has a lower coefficient of friction, it also has lower hardness. The composite structure film has a smaller coefficient of friction, but its hardness is much greater than that of the single-structure film.

[0101] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A wear-resistant and lubricating composite thin film for space applications, characterized in that, It includes a metal transition layer, a gradient transition layer, a low-stress aC layer, a ta-C layer and an aC:H layer sequentially stacked on a metal substrate.

2. The space durable lubricating composite structure film according to claim 1, wherein, The metal transition layer includes a Ti transition layer.

3. The space durable lubricating composite structure film according to claim 1, wherein, The gradient transition layer includes a Ti / C transition layer.

4. The space durable lubricating composite structure film according to claim 1, wherein, The thickness of the metal transition layer is 50~70 nm.

5. The space-qualified wear-resistant, lubricious composite thin film of claim 1, wherein, The thickness of the gradient transition layer is 50~70 nm.

6. The space durable lubricating composite structure film according to claim 1, wherein, The thickness of the low-stress aC layer is 100~150 nm.

7. The space-qualified wear-resistant, lubricious composite thin film of claim 1, wherein, The thickness of the ta-C layer is 200~300 nm.

8. The space durable lubricating composite structure film according to claim 1, wherein, The thickness of the aC:H layer is 500~600 nm.

9. The space-qualified wear-resistant, lubricious composite thin film of claim 1, wherein, The metal matrix material includes at least one of stainless steel, high-speed steel, and bearing steel.

10. The method of claim 1 to 9, wherein the space is a space between a bearing and a shaft. include: A metal transition layer, a gradient transition layer, a low-stress aC layer, a ta-C layer, and an aC:H layer are sequentially prepared on a metal substrate. The metal transition layer, the gradient transition layer, the low-stress aC layer, and the aC:H layer are prepared using high-power magnetron sputtering technology, while the ta-C layer is prepared using electromagnetically controlled cathode arc technology.

Images