W-S-Ti-O lubricating film as well as preparation method and application thereof

Abstract

The invention provides a W-S-Ti-O lubricating film and a preparation method and application thereof, and belongs to the technical field of space lubrication. The invention provides a W-S-Ti-O lubricating film, and the W-S-Ti-O lubricating film has a compact amorphous structure and is composed of a WS2 phase, a WSxOy phase and a TiO2 phase. According to the invention, Ti and O elements are introduced into the WS2-based thin film to inhibit the growth of WS2 crystals, so that the W-S-Ti-O lubricating thin film with an amorphous compact structure is formed, and the W-S-Ti-O lubricating thin film has good vacuum tribology performance and space irradiation resistance, especially atomic oxygen erosion resistance. The result of the embodiment shows that the prepared W-S-Ti-O lubricating film shows good atomic oxygen irradiation resistance after being irradiated by the exposed environment of the windward side outside the space station cabin for 6 months, the vacuum friction coefficient of the irradiated film is 0.03, and the lubricating life is longer than 4.0 * 10 < 5 > r.

Description

Technical Field

[0001] The present invention relates to the technical field of space lubrication, and particularly to a W-S-Ti-O lubricating film and its preparation method and application. Background Art

[0002] In aerospace vehicles for space science and applications, lubricating materials are one of the core basic materials to ensure the long-life and highly reliable operation of mechanical moving parts. Due to the special nature of the space environment (such as high vacuum, extreme temperature alternation, strong irradiation, etc.), traditional liquid lubricants are prone to volatilization or failure. Therefore, solid lubricating films with low friction coefficients and high chemical stability have become a key technology in the field of space lubrication. Among them, transition metal dichalcogenides (TMDs, such as MoS2, WS2, etc.) are widely used in the surface lubrication protection of key components such as satellite bearings and solar wing deployment mechanisms due to their layered structure and excellent vacuum lubrication performance.

[0003] However, the problem of performance degradation of lubricating films under the space irradiation environment (especially atomic oxygen erosion) of spacecraft has become increasingly prominent. In low Earth orbit (LEO, altitude 200 - 700 km), the flux of high-energy atomic oxygen (formed by the decomposition of oxygen molecules by solar ultraviolet radiation) is as high as 10 14 ~10 15 atoms / (cm²·s). Its strong oxidizing property will react with the TMDs film, resulting in the oxidation and loss of surface sulfur elements and the destruction of the layered structure, thereby significantly reducing the lubrication performance and wear resistance life of the film. Research shows that after exposure to the atomic oxygen environment, the friction coefficient of the MoS2 film may sharply rise from the initial 0.02 - 0.05 to above 0.2, and the wear life is significantly shortened.

[0004] Although related technologies have tried to improve the radiation resistance of TMDs films through means such as metal element doping (such as titanium, gold, etc.) and multi-layer structure design, their resistance to atomic oxygen is still significantly insufficient. For example, although doping modification can partially inhibit the oxidation reaction, it may sacrifice the intrinsic lubrication performance of the film. Therefore, the development of TMDs-based space lubricating films with excellent lubrication performance and high resistance to atomic oxygen erosion has become an important requirement for breaking through the long-life technical bottleneck of aerospace equipment and ensuring the reliability of space missions in special space environments. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a W-S-Ti-O lubricating film and its preparation method and application. The W-S-Ti-O lubricating film of the present invention has good vacuum tribological properties and the ability to resist space irradiation, especially atomic oxygen erosion.

[0006] To achieve the above-mentioned invention object, the present invention provides the following technical solutions: The present invention provides a W-S-Ti-O lubricating thin film, and the W-S-Ti-O lubricating thin film has a dense amorphous structure and is composed of WS2 phase, WS x O y phase and TiO2 phase, where 0 < x < 2, 0 < y < 3, x is the atomic content ratio of S to W in the WS x O y phase, y is the atomic content ratio of O to W in the WS x O y phase, the content of O element in the W-S-Ti-O lubricating thin film is 25-50 at.%, the content of Ti element is 2-8 at.%, and the atomic content ratio of S element to W element is 1.3-1.6:1.

[0007] Preferably, the content of O element in the W-S-Ti-O lubricating thin film is 30.2-45 at.%, the content of Ti element is 3-7 at.%, and the atomic content ratio of S element to W element is 1.33-1.5:1.

[0008] Preferably, the thickness of the W-S-Ti-O lubricating thin film is 1-3 μm.

[0009] The present invention also provides a preparation method of the W-S-Ti-O lubricating thin film described in the above technical solution, including the following steps: Ion bombard the substrate to obtain a pretreated substrate; Use a WS2 target and a Ti-containing target, and use a mixed gas of Ar and O2 as the working gas, and deposit a film on the pretreated substrate by magnetron sputtering to obtain the W-S-Ti-O lubricating thin film.

[0010] Preferably, during the film deposition, co-sputtering is performed on the WS2 target and the Ti-containing target. The number of WS2 targets used in the co-sputtering is 2, and the number of Ti-containing targets is 1.

[0011] Preferably, the conditions for the co-sputtering include: the perpendicular distance between the WS2 target and the Ti-containing target and the surface of the pretreated substrate is independently 100-200 mm, the pressure of the working gas is 1.0-2.0 Pa, the flow ratio of O2 to Ar is (0.02-0.08):1, the sputtering power density of the WS2 target is 2-4 W / cm 2 , the sputtering power density of the Ti-containing target is 0.5-1.2 W / cm 2 , the bias voltage is -10 to -60 V, and the deposition time is 60-120 min.

[0012] Preferably, the Ti-containing target is a Ti target or a TiO2 target.

[0013] Preferably, the working gas for ion bombardment is argon, the pressure of the working gas is 1.0 - 3.0 Pa, the voltage is -500 - -800 V, and the time is 15 - 30 min.

[0014] Preferably, the material of the substrate is stainless steel or titanium alloy.

[0015] The present invention also provides the application of the W - S - Ti - O lubricating film described in the above technical solution or the W - S - Ti - O lubricating film prepared by the preparation method described in the above technical solution in the field of lubrication for resisting space atomic oxygen irradiation.

[0016] The present invention provides a W - S - Ti - O lubricating film. The W - S - Ti - O lubricating film has a dense amorphous structure and is composed of WS2 phase, WS x O y phase and TiO2 phase, where 0 < x < 2, 0 < y < 3, x is the atomic content ratio of S to W in the WS x O y phase, y is the atomic content ratio of O to W in the WS x O y phase. The content of O element in the W - S - Ti - O lubricating film is 25 - 50 at.%, the content of Ti element is 2 - 8 at.%, and the atomic content ratio of S element to W element is 1.3 - 1.6:1.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention introduces Ti and O elements into the WS2 - based film, inhibits the growth of WS2 crystals, and thus forms a W - S - Ti - O lubricating film with an amorphous dense structure, which has good vacuum tribological properties and the ability to resist space irradiation, especially atomic oxygen erosion. The results of the examples show that the W - S - Ti - O lubricating film prepared by the present invention shows good atomic oxygen irradiation resistance performance after being irradiated in the exposed environment on the windward side outside the space station cabin for 6 months. The vacuum friction coefficient of the film after irradiation is 0.03, and the lubrication life is higher than 4.0×10 5 r.

[0018] The present invention also provides a preparation method of the W - S - Ti - O lubricating film described in the above technical solution. The present invention uses a WS2 target and a Ti - containing target, takes a mixed gas of Ar and O2 as the working gas, and introduces Ti and O elements into the WS2 - based film through magnetron sputtering to inhibit the growth of WS2 crystals, thereby forming a W - S - Ti - O lubricating film with an amorphous dense structure. Description of the Drawings

[0019] Figure 1 Field emission scanning electron microscope image of the cross section of the W-S-Ti-O lubricating film prepared in Example 1; Figure 2 XPS spectrum of element W in the W-S-Ti-O lubricating film prepared in Example 1, Figure 2 The circles in it represent the measured values, and the curve is obtained by fitting the measured values; Figure 3 XPS spectrum of element Ti in the W-S-Ti-O lubricating film prepared in Example 1, Figure 3 The circles in it represent the measured values, and the curve is obtained by fitting the measured values; Figure 4 Comparison diagram of the vacuum tribological properties of the W-S-Ti-O lubricating film prepared in Example 1 and the pure WS2 lubricating film prepared in Comparative Example 1; Figure 5 SEM morphology diagram of the W-S-Ti-O lubricating film prepared in Example 2; Figure 6 EDS spectrum of the W-S-Ti-O lubricating film prepared in Example 2; Figure 7 Vacuum friction test curve of the W-S-Ti-O lubricating film prepared in Example 2; Figure 8 Vacuum friction test curve of the W-S-Ti-O lubricating film prepared in Example 1 after being exposed to the windward side outside the space station cabin for 6 months. Detailed implementation manners

[0020] The present invention provides a W-S-Ti-O lubricating film, and the W-S-Ti-O lubricating film has a dense amorphous structure and is composed of WS2 phase, WS x O y phase and TiO2 phase, 0 < x < 2, 0 < y < 3, x is the atomic content ratio of S to W in the WS x O y phase, y is the atomic content ratio of O to W in the WS x O y phase, the content of element O in the W-S-Ti-O lubricating film is 25-50 at.%, the content of element Ti is 2-8 at.%, and the atomic content ratio of S element to W element is 1.3-1.6:1.

[0021] In the present invention, the content of the O element in the W-S-Ti-O lubricating thin film is 25-50 at.%, specifically it can be 25 at.%, 30.2 at.%, 35 at.%, 40 at.%, 45 at.% or 50 at.%, the content of the Ti element is 2-8 at.%, specifically it can be 2 at.%, 3 at.%, 4 at.%, 5.1 at.%, 6 at.%, 7 at.% or 8 at.%, and the atomic content ratio of the S element to the W element is 1.3-1.6:1, specifically it can be 1.3:1, 1.33:1, 1.4:1, 1.5:1 or 1.6:1. In the present invention, Ti and O elements are introduced into the WS2-based thin film to inhibit the growth of WS2 crystals, thereby forming a W-S-Ti-O lubricating thin film with an amorphous dense structure, which has good vacuum tribological properties and the ability to resist space irradiation, especially atomic oxygen erosion.

[0022] In the present invention, the thickness of the W-S-Ti-O lubricating thin film is preferably 1-3 μm, specifically it can be 1, 1.2, 1.34, 1.8, 2, 2.5 or 3 μm.

[0023] The vacuum friction coefficient of the W-S-Ti-O lubricating thin film of the present invention is as low as 0.02, and the wear-resistant life > 5.0×10 5 r. After being irradiated by the exposure environment on the windward side outside the space station cabin for 6 months, the vacuum friction coefficient is as low as 0.03, and the lubricating life is higher than 4.0×10 5 r.

[0024] The present invention also provides a preparation method of the W-S-Ti-O lubricating thin film described in the above technical solution, including the following steps: Ion bombard the substrate to obtain a pretreated substrate; Use a WS2 target and a Ti-containing target, and use a mixed gas of Ar and O2 as the working gas, and deposit a film on the pretreated substrate by magnetron sputtering to obtain the W-S-Ti-O lubricating thin film.

[0025] In the present invention, unless otherwise specified, the raw materials used are all commercially available products in the art.

[0026] The present invention ion bombards the substrate to obtain a pretreated substrate.

[0027] In the present invention, the working gas for ion bombardment is preferably argon, the gas pressure of the working gas is preferably 1.0 - 3.0 Pa, specifically it can be 1.0, 1.5, 2.0, 2.5 or 3.0 Pa, the voltage is preferably -500 - -800 V, specifically it can be -500, -600, -700 or -800 V, and the time is preferably 15 - 30 min, specifically it can be 15, 18, 20, 25 or 30 min. Controlling the parameters of the ion bombardment within the above ranges can effectively remove the adsorbed pollutants on the surface of the substrate.

[0028] In the present invention, the process of the ion bombardment preferably includes: placing the substrate on the workpiece holder in the vacuum chamber, after adjusting the distance between the substrate and the sputtering target, evacuating the vacuum to a background vacuum ≤ 1.0×10 -3 Pa, then filling with argon gas, starting the rotation of the workpiece holder, and performing Ar ion bombardment treatment. In the present invention, the rotation speed of the workpiece holder in the vacuum chamber is preferably 1.0 - 2.0 r / min.

[0029] In the present invention, the material of the substrate is preferably stainless steel or titanium alloy. The present invention has no special limitation on the specific composition of the stainless steel or titanium alloy, and the compositions of the stainless steel or titanium alloy well-known to those skilled in the art can be adopted. In a specific embodiment of the present invention, the material of the substrate is 9Cr18 steel.

[0030] In the present invention, before performing ion bombardment on the substrate, it preferably further includes sequentially cleaning and drying the substrate; the cleaning is preferably ultrasonic cleaning of the substrate in acetone and absolute ethanol in sequence, and the ultrasonic cleaning time in both acetone and absolute ethanol is preferably 15 min; the acetone is preferably analytical pure acetone; the present invention has no special limitation on the frequency of the ultrasonic cleaning, and the frequency well-known to those skilled in the art can be adopted. In the present invention, the drying method is preferably drying in an oven, and the present invention has no special limitation on the drying process, and the process well-known to those skilled in the art can be adopted. In an embodiment of the present invention, the drying is specifically performed in an infrared oven.

[0031] After obtaining the pretreated substrate, the present invention uses a WS2 target and a Ti-containing target, and uses a mixed gas of Ar and O2 as the working gas, and deposits a film on the pretreated substrate by magnetron sputtering to obtain the W - S - Ti - O lubricating film.

[0032] In the present invention, during the process of depositing the coating film, it is preferable to co-sputter the WS2 target and the Ti-containing target (i.e., simultaneously sputter the WS2 target and the Ti-containing target). The number of WS2 targets used in the co-sputtering is preferably 2, and the number of Ti-containing targets is preferably 1, which can effectively control the contents of Ti element and O element in the W-S-Ti-O lubricating film. In a specific embodiment of the present invention, 2 WS2 targets are connected by a radio frequency power supply, 1 Ti target is connected by a DC pulsed power supply or a TiO2 target is connected by a radio frequency power supply, and the W-S-Ti-O lubricating film is prepared by simultaneously sputtering 2 WS2 targets and 1 Ti-containing target; both the WS2 target and the Ti-containing target are preferably rectangular targets with a size of 400 mm×100 mm, and the thickness of the rectangular target is independently preferably 4-8 mm.

[0033] In the present invention, the conditions for the co-sputtering preferably include: the vertical distance between the WS2 target and the Ti-containing target and the surface of the pretreated substrate is independently 100-200 mm, specifically it can be 100, 110, 160 or 200 mm, the gas pressure of the working gas is 1.0-2.0 Pa, specifically it can be 1.0, 1.2, 1.8 or 2.0 Pa, the flow ratio of O2 to Ar is (0.02-0.08):1, specifically it can be 0.02:1, 0.03:1, 0.06:1 or 0.08:1, the sputtering power density of the WS2 target is 2-4 W / cm 2 , specifically it can be 2, 2.4, 2.5, 3, 3.2 or 4 W / cm 2 , the sputtering power density of the Ti-containing target is 0.5-1.2 W / cm 2 , specifically it can be 0.5, 0.6, 0.75, 0.9 or 1.2 W / cm 2 , the bias voltage is -10 to -60 V, specifically it can be -10, -20, -30, -40, -50 or -60 V, and the deposition time is 60-120 min, specifically it can be 60, 70, 80, 100 or 120 min. Controlling the conditions of the co-sputtering within the above ranges can obtain a lubricating film with a controllable thickness suitable for use in space precision moving parts.

[0034] In the present invention, the Ti-containing target is preferably a Ti target or a TiO2 target.

[0035] The present invention also provides the application of the W-S-Ti-O lubricating film described in the above technical solution or the W-S-Ti-O lubricating film prepared by the preparation method described in the above technical solution in the field of lubrication against space atomic oxygen irradiation.

[0036] The present invention does not have any special limitation on the method of the application, and any method well-known to those skilled in the art can be used.

[0037] Next, in combination with the embodiments of the present invention, the technical solutions in the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0038] Example 1 Put 9Cr18 steel into analytical pure acetone and absolute ethanol in sequence, ultrasonically clean each for 15 min, put it into an infrared oven to dry, then place it on the workpiece rack in the vacuum chamber, and adjust the vertical distance between the substrate and the target surface of the sputtering target to 150 mm; evacuate the vacuum chamber. When the background vacuum is better than 1.0×10 -3 Pa, fill the vacuum chamber with argon, the gas pressure is 2.0 Pa, start the rotation of the workpiece rack, the rotation speed is 1.5 r / min, the bias voltage is -600 V, and bombard with Ar ions for 20 min.

[0039] During sputtering, 2 pieces of WS2 targets and 1 piece of Ti target are used. The targets are all rectangular targets with a size of 400 mm×100 mm and a thickness of 6.0 mm. Adjust the Ar gas flow rate and O2 gas flow rate, adjust the gas pressure to 1.5 Pa, the flow rate ratio of oxygen to argon is 0.08:1, add the bias voltage to -30 V, turn on the radio frequency sputtering power supply, set the sputtering power of the two groups of WS2 targets to 1 kW (2.5 W / cm 2 ), turn on the DC pulse power supply, set the sputtering power of the Ti target to 200 W (0.5 W / cm 2 ). After the film is deposited for 90 min, stop sputtering to obtain a W-S-Ti-O lubricating film (the thickness is 1.8 μm, the O element content in the film is 45 at.%, the Ti element content is 2.5 at.%, and the atomic content ratio of S element to W element is 1.4:1).

[0040] Example 2 Put 9Cr18 steel into analytical pure acetone and absolute ethanol in sequence, ultrasonically clean each for 15 min, put it into an infrared oven to dry, then place it on the workpiece rack in the vacuum chamber, and adjust the vertical distance between the substrate and the target surface of the sputtering target to 150 mm; evacuate the vacuum chamber. When the background vacuum is better than 1.0×10 -3 Pa, fill the vacuum chamber with argon, the gas pressure is 2.0 Pa, start the rotation of the workpiece rack, the rotation speed is 2.0 r / min, the bias voltage is -600 V, and bombard with Ar ions for 20 min.

[0041] During sputtering, 2 pieces of WS2 targets and 1 piece of TiO2 target are used. The targets are all rectangular targets with a size of 400 mm × 100 mm and a thickness of 6.0 mm. Adjust the flow rates of Ar gas and O2 gas, adjust the air pressure to 1.5 Pa, the flow rate ratio of oxygen to argon is 0.02:1, apply a bias voltage of -30 V, turn on the radio frequency sputtering power supply, and set the sputtering power of the two groups of WS2 targets to 1 kW (2.5 W / cm 2 ) Turn on the DC pulse power supply, and set the sputtering power of the Ti target to 300 W (0.75 W / cm 2 ). After the film is deposited for 65 minutes, stop sputtering to obtain a W-S-Ti-O lubricating film (with a thickness of 1.34 μm, the O element content in the film is 30.2 at.%, the Ti element content is 5.1 at.%, and the atomic content ratio of S element to W element is 1.33:1).

[0042] Comparative Example 1: Pure WS2 lubricating film Put 9Cr18 steel into analytical pure acetone and absolute ethanol in turn and ultrasonically clean for 15 minutes each. After drying in an infrared oven, place it on the workpiece rack in the vacuum chamber, and adjust the vertical distance between the substrate and the target surface of the sputtering target to 150 mm; evacuate the vacuum chamber. When the background vacuum is better than 1.0×10 -3 Pa, fill the vacuum chamber with argon, the air pressure is 0.8 Pa, turn on the rotation of the workpiece rack, the rotation speed is 1.5 r / min, the bias voltage is -600 V, and bombard with Ar ions for 20 minutes.

[0043] During sputtering, the targets used are 2 pieces of WS2 targets. The targets are rectangular targets with a size of 400 mm × 100 mm and a thickness of 6.0 mm. Adjust the flow rate of Ar gas, adjust the air pressure to 1.5 Pa, apply a bias voltage of -30 V, turn on the radio frequency sputtering power supply, and set the sputtering power of the two groups of WS2 targets to 1 kW (2.5 W / cm 2 ). After the film is deposited for 120 minutes, stop sputtering to obtain a pure WS2 lubricating film (with a thickness of 1.5 μm).

[0044] Test Example Perform morphology, composition testing, and tribological performance testing on the W-S-Ti-O lubricating film prepared in Example 1 and the pure WS2 lubricating film prepared in Comparative Example 1; and test the structure and performance of the film after the extravehicular irradiation experiment in Example 1; among them, the friction experiment is carried out according to the GJB3032-97 standard, that is, the friction coefficient and wear resistance life of the film are evaluated by a ball-on-disk friction test device. The test conditions are: room temperature, the normal load is 5.00 N, the sample rotation speed is (1000 ± 2) r / min, and the counterbody is a 9Cr18 steel ball with a diameter of 8 mm; the test environment is a vacuum condition (the vacuum degree is better than 1.0×10 -3 Pa).

[0045] Test results Figure 1 Field emission scanning electron microscope image of the cross-section of the W-S-Ti-O lubricating film prepared for Example 1 Figure 2 XPS spectrum of W element in the W-S-Ti-O lubricating film prepared for Example 1 Figure 3 XPS spectrum of Ti element in the W-S-Ti-O lubricating film prepared for Example 1; It can be seen that the W-S-Ti-O lubricating film prepared in Example 1 is a dense amorphous structure, and the film is mainly composed of WS2, WS Figures 1 to 3 It can be seen that the W-S-Ti-O lubricating film prepared in Example 1 is a dense amorphous structure, and the film is mainly composed of WS2, WS x O y and TiO2 phases.

[0046] Figure 4 Comparison chart of the vacuum tribological properties of the W-S-Ti-O lubricating film prepared for Example 1 and the pure WS2 lubricating film prepared for Comparative Example 1. It can be seen that the average vacuum friction coefficient of the W-S-Ti-O lubricating film prepared in Example 1 is 0.02, and the lubrication life is 8.0×10 5 r, and both the friction coefficient and the lubrication life are significantly higher than those of Comparative Example 1.

[0047] Figure 5 SEM morphology diagram of the W-S-Ti-O lubricating film prepared for Example 2 Figure 6 EDS spectrum of the W-S-Ti-O lubricating film prepared for Example 2 Figure 7 Vacuum friction test curve of the W-S-Ti-O lubricating film prepared for Example 2. It can be seen that the W-S-Ti-O lubricating film prepared in Example 2 is a dense amorphous structure, with a thickness of 1.34 μm, the O element content in the film is 30.2 at.%, and the Ti element content is 5.1 at.%. The average vacuum friction coefficient is less than 0.03, and the lubrication life is 8.0×10 5 r.

[0048] Figure 8 Vacuum friction test curve of the W-S-Ti-O lubricating film prepared for Example 1 after being exposed to the windward side outside the space station cabin for 6 months. It can be seen that the average friction coefficient of the W-S-Ti-O lubricating film obtained in Example 1 after being irradiated by atomic oxygen in space is 0.03, and the lubrication life is higher than 4.0×10 5 r.

[0049] The average friction coefficient of the W-S-Ti-O lubricating film obtained in Example 2 after being irradiated by simulated space atomic oxygen is 0.03, and the lubrication life is higher than 4.0×10 5 r.

[0050] The above are only the preferred embodiments of the present invention and do not impose any formal restrictions on the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A W-S-Ti-O lubricating film, characterized in that, The W-S-Ti-O lubricating thin film has a dense amorphous structure and is composed of WS2 phase, WS x O y phase and TiO2 phase, where 0 < x < 2, 0 < y < 3, x is the atomic content ratio of S to W in the WS x O y phase, y is the atomic content ratio of O to W in the WS x O y phase. The content of O element in the W-S-Ti-O lubricating thin film is 25-50 at.%, the content of Ti element is 2-8 at.%, and the atomic content ratio of S element to W element is 1.3-1.6:

1.

2. The W-S-Ti-O lubricating thin film according to claim 1, wherein The content of O element in the W-S-Ti-O lubricating thin film is 30.2 - 45 at.%, the content of Ti element is 3 - 7 at.%, and the atomic content ratio of S element to W element is 1.33 - 1.5:

1.

3. The W-S-Ti-O lubricating thin film according to claim 1, wherein The thickness of the W-S-Ti-O lubricating thin film is 1 - 3 μm.

4. The preparation method of the W-S-Ti-O lubricating thin film according to any one of claims 1 to 3, characterized in that, It includes the following steps: Ion bombardment is carried out on the substrate to obtain a pretreated substrate; Using a WS2 target and a Ti-containing target, with a mixed gas of Ar and O2 as the working gas, the pretreated substrate is deposited and coated by magnetron sputtering to obtain the W-S-Ti-O lubricating thin film.

5. The preparation method according to claim 4, characterized in that, During the process of the deposition coating, co-sputtering is carried out on the WS2 target and the Ti-containing target. The number of WS2 targets used in the co-sputtering is 2 pieces, and the number of the Ti-containing targets is 1 piece.

6. The preparation method according to claim 5, wherein, The conditions for the co-sputtering include: the perpendicular distances between the WS2 target and the Ti-containing target and the surface of the pretreated substrate are independently 100-200 mm, the gas pressure of the working gas is 1.0-2.0 Pa, the flow ratio of O2 to Ar is (0.02-0.08):1, the sputtering power density of the WS2 target is 2-4 W / cm 2 , and the sputtering power density of the Ti-containing target is 0.5-1.2 W / cm 2 , the bias voltage is -10 to -60 V, and the deposition time is 60-120 min.

7. The preparation method according to claim 4 or 5, characterized in that The Ti-containing target is a Ti target or a TiO2 target.

8. The preparation method according to claim 4, wherein, The working gas for the ion bombardment is argon, the pressure of the working gas is 1.0 - 3.0 Pa, the voltage is -500 - 800 V, and the time is 15 - 30 min.

9. The preparation method according to claim 4 or 8, characterized in that, The material of the substrate is stainless steel or titanium alloy.

10. Application of the W-S-Ti-O lubricating thin film according to any one of claims 1 - 3 or the W-S-Ti-O lubricating thin film prepared by the preparation method according to any one of claims 4 - 9 in the field of lubrication against space atomic oxygen irradiation.

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