A MoS2-WS2 based composite thin film, its preparation method and application

Abstract

The application belongs to the technical field of space lubricating materials, and particularly relates to a MoS2-WS2-based composite film and a preparation method and application thereof. The preparation method of the MoS2-WS2-based composite film provided by the application comprises the following steps: after a base material is ion-bombarded and cleaned, non-equilibrium magnetron sputtering is performed on the base material by using a MoS2 target and a WS2 target, or a MoS2 target, a WS2 target and a metal Ti target, so as to form a MoS2-WS2-based composite film; and according to an atomic percentage, the MoS2-WS2-based composite film contains 0-13.5% Ti, 13.0-27.3% W, 14.4-38.4% Mo and a balance of S and impurity elements. MoS2 and WS2 with similar crystal structures are combined together by using non-equilibrium magnetron sputtering, and the obtained composite film has excellent tribological properties in a vacuum environment, and still has a relatively low friction coefficient and a relatively long wear life after being irradiated by atomic oxygen.

Description

Technical Field

[0001] This invention belongs to the field of space lubrication materials technology, specifically relating to a MoS2-WS2 based composite film, its preparation method, and its application. Background Technology

[0002] Space lubrication materials are one of the key factors in ensuring the safe, reliable, and long-term operation of spacecraft motion mechanisms in orbit. MoS2 and WS2 are typical representatives of transition metal dichalcogenides and are widely used in the aerospace field due to their excellent vacuum lubrication properties.

[0003] However, pure MoS2 and WS2 films have a porous structure and short wear life, making it difficult to meet the requirements of long life and high reliability for space missions such as deep space exploration. Therefore, improving the structure and lubrication properties of dichalcogenide films has attracted widespread attention and research.

[0004] To improve the wear resistance of dichalcogenide films, elemental doping has been a common method for composite formation. However, this doping method faces the following problems: the doping precision and uniformity are difficult to control, making it difficult to control the lubrication performance of the material; the introduction of dopant elements can cause lattice distortion in transition metal dichalcogenide compounds, forming defects and destroying the original structure; at the same time, the introduced dopant may desorb over time or under specific conditions (such as heating), leading to degradation or even disappearance of the doping effect.

[0005] Therefore, exploring how to improve the wear resistance of space lubrication materials has important application value and practical significance for the development of future long-life spacecraft. Summary of the Invention

[0006] In view of this, the present invention provides a MoS2-WS2 based composite film, its preparation method and application. The MoS2-WS2 based composite film prepared according to the preparation method provided by the present invention has a low coefficient of friction and a long wear life under vacuum conditions; and it still has good wear resistance after atomic oxygen irradiation, making it suitable for use as a space lubricating material.

[0007] To address the aforementioned technical problems, this invention provides a method for preparing MoS2-WS2-based composite thin films, comprising the following steps: After ion bombardment cleaning of the substrate material, unbalanced magnetron sputtering is performed using MoS2 and WS2 targets, or MoS2, WS2 and Ti targets, to form a MoS2-WS2 based composite film. The MoS2-WS2 based composite film contains 0~13.5% Ti, 13.0~27.3% W, 14.4~38.4% Mo and the balance S and impurity elements, based on atomic percentage. The conditions for the unbalanced magnetron sputtering include: MoS2 target power of 200~600W, WS2 target power of 200~600W, Ti target current of 0~0.2A, argon flow rate of 50~70SCCM, negative bias voltage of 18~22V, and deposition time of 100~120min.

[0008] Preferably, the thickness of the MoS2-WS2-based composite film is 1~2μm.

[0009] Preferably, a Ti transition layer is deposited between the substrate and the MoS2-WS2-based composite film; the conditions for depositing the Ti transition layer include: using a metallic Ti target as the target material, using argon gas as the sputtering gas source, the metallic Ti target current is 0.1~0.2A, the argon gas flow rate is 30~50SCCM, the negative bias voltage is 80~120V, and the deposition time is 10~15min.

[0010] Preferably, the thickness of the Ti transition layer is 48~52nm.

[0011] Preferably, the ion bombardment cleaning includes the following steps: evacuating the coating chamber using a vacuum pump until the pressure inside the chamber is 3.0 × 10⁻⁶. -3 When the pressure is below 1 Pa, 28-32 SCCM of argon gas is introduced into the chamber, while a negative bias voltage of 380-420V is applied to the substrate material.

[0012] Preferably, the substrate comprises 9Cr18 steel or silicon wafer.

[0013] The present invention also provides a MoS2-WS2-based composite film prepared according to the preparation method described above, comprising MoS2 and WS2, or comprising MoS2, WS2 and Ti; the MoS2-WS2-based composite film contains, by atomic percentage, 0~13.5% Ti, 13.0~27.3% W, 14.4~38.4% Mo and the balance S and impurity elements.

[0014] Preferably, the MoS2-WS2 based composite film further includes a Ti transition layer between itself and the substrate material.

[0015] Preferably, the thickness of the MoS2-WS2-based composite film is 1~2 μm; the thickness of the Ti transition layer is 48~52 nm; The MoS2-WS2 based composite film exhibits an average coefficient of friction of <0.04 in vacuum and a wear resistance life of >10. 5 change.

[0016] This invention also provides the application of the MoS2-WS2 based composite film described in the above technical solution as a space lubrication material.

[0017] This invention provides a method for preparing a MoS2-WS2-based composite thin film, comprising the following steps: after ion bombardment cleaning of the substrate material, unbalanced magnetron sputtering is performed using a MoS2 target and a WS2 target, or a MoS2 target, a WS2 target, and a metallic Ti target to form a MoS2-WS2-based composite thin film; the MoS2-WS2-based composite thin film contains, by atomic percentage, 0-13.5% Ti, 13.0-27.3% W, 14.4-38.4% Mo, and the balance being S and impurity elements; the unbalanced magnetron sputtering conditions include: MoS2 target power of 200-600 W, WS2 target power of 200-600 W, metallic Ti target current of 0-0.2 A, argon flow rate of 50-70 SCCM, negative bias voltage of 18-22 V, and deposition time of 100-120 min. This invention uses unbalanced magnetron sputtering to combine MoS2 and WS2, which have similar crystal structures, to obtain a composite film with good mechanical properties and excellent tribological properties in a vacuum environment. Even after atomic oxygen irradiation, it still has a low coefficient of friction and a long wear life, which can meet the requirements of long-life spacecraft for space lubrication materials. Attached Figure Description

[0018] Figure 1 SEM image of the cross section of the MoS2-WS2 composite thin film material prepared in Example 1; Figure 2 SEM image of the cross section of the MoS2-WS2 composite thin film material prepared in Example 2; Figure 3 SEM image of the cross section of the MoS2-WS2 composite thin film material prepared in Example 3; Figure 4 SEM image of the cross section of the MoS2-WS2 composite thin film material prepared in Example 4; Figure 5 The friction curves of the MoS2-WS2 composite films prepared in Examples 1-4 under vacuum conditions are shown. Figure 6 The friction curves of the films prepared in comparative examples 1 and 2 under vacuum conditions are shown. Figure 7 The vacuum friction curves of the MoS2-WS2 composite films prepared in Examples 1-4 after atomic oxygen irradiation are shown. Detailed Implementation

[0019] This invention provides a method for preparing MoS2-WS2-based composite thin films, comprising the following steps: After ion bombardment cleaning of the substrate material, unbalanced magnetron sputtering is performed using MoS2 and WS2 targets, or MoS2, WS2 and Ti targets, to form a MoS2-WS2 based composite film. The MoS2-WS2 based composite film contains 0~13.5% Ti, 13.0~27.3% W, 14.4~38.4% Mo and the balance S and impurity elements, based on atomic percentage. The conditions for the unbalanced magnetron sputtering include: MoS2 target power of 200~600W, WS2 target power of 200~600W, Ti target current of 0~0.2A, argon flow rate of 50~70SCCM, negative bias voltage of 18~22V, and deposition time of 100~120min.

[0020] In this invention, the substrate may include 9Cr18 steel or silicon wafer. Before ion bombardment cleaning, the substrate material may be ultrasonically cleaned in ethanol and petroleum ether in sequence.

[0021] In this invention, the ion bombardment cleaning may include the following steps: evacuating the coating chamber using a vacuum pump until the pressure inside the chamber is 3.0 × 10⁻⁶. -3 When the pressure is below 3.0 Pa, 28-32 SCCM of argon gas is introduced into the chamber, while a negative bias of 380-420 V is applied to the substrate material; specifically, when the pressure inside the chamber is 3.0 × 10⁻⁶ Pa... -3 At a pressure of 30 SCCM, argon gas is introduced into the chamber while a negative bias voltage of 400 V is applied to the substrate material. This invention removes contaminants from the surface of the substrate material through ion bombardment cleaning.

[0022] In this invention, the purity of the MoS2 target can be above 99.99%, specifically 99.99%; the purity of the WS2 target can be above 99.99%, specifically 99.99%; and the purity of the metallic Ti target can be above 99.99%, specifically 99.99%.

[0023] In this invention, the conditions for unbalanced magnetron sputtering may include: a MoS2 target power of 200-600W, a WS2 target power of 200-600W, a metallic Ti target current of 0-0.2A, an argon flow rate of 50-70SCCM, a negative bias voltage of 18-22V, and a deposition time of 100-120min; the MoS2 target power may specifically be 200W, 300W, 400W, 500W, or 600W; the WS2 target power may specifically be 200W, 300W, 400W, 500W, or 600W; the metallic Ti target current may specifically be 0A, 0.1A, or 0.2A; the argon flow rate may specifically be 50SCCM, 60SCCM, or 70SCCM; the negative bias voltage may specifically be 20V; and the deposition time may specifically be 110min.

[0024] In this invention, the conditions for the unbalanced magnetron sputtering can be specifically as follows: MoS2 target power 600W, WS2 target power 600W, metallic Ti target current 0.2A, argon flow rate 70SCCM, negative bias voltage 20V, and deposition time 110min; or MoS2 target power 600W, WS2 target power 600W, metallic Ti target current 0A (the MoS2-WS2 based composite film does not contain Ti), argon flow rate 70SCCM, negative bias voltage 20V, and deposition time 110min. n; MoS2 target power is 600W, WS2 target power is 200W, metallic Ti target current is 0A (MoS2-WS2 based composite film does not contain Ti), argon flow rate is 70SCCM, negative bias voltage is 20V, and deposition time is 110min; MoS2 target power is 200W, WS2 target power is 600W, metallic Ti target current is 0A (MoS2-WS2 based composite film does not contain Ti), argon flow rate is 70SCCM, negative bias voltage is 20V, and deposition time is 110min.

[0025] In this invention, after the unbalanced magnetron sputtering, the process further includes: turning off the bias voltage and sputtering power supply, stopping the gas supply, and continuing to pump gas for 120 minutes.

[0026] This invention can deposit a Ti transition layer between the substrate and the MoS2-WS2-based composite film. The conditions for depositing the Ti transition layer may include: using a metallic Ti target as the target material, argon gas as the sputtering gas source, a metallic Ti target current of 0.1~0.2A, an argon gas flow rate of 30~50SCCM, a negative bias voltage of 80~120V, and a deposition time of 10~15min; or using a metallic Ti target as the target material, argon gas as the sputtering gas source, a metallic Ti target current of 0.1A, an argon gas flow rate of 30~40SCCM, a negative bias voltage of 100~110V, and a deposition time of 10~13min.

[0027] In this invention, the thickness of the Ti transition layer can be 48-52 nm, specifically 50 nm. In this invention, the Ti transition layer serves to enhance adhesion and provide support.

[0028] In this invention, the thickness of the MoS2-WS2-based composite film can be 1~2μm, specifically 1.1μm, 1.4μm, 1.5μm, 1.6μm or 1.8μm; the MoS2-WS2-based composite film has friction-reducing and wear-resistant properties.

[0029] In this invention, the atomic percentage of Ti in the MoS2-WS2-based composite film is 0-13.5%, specifically 0, 2%, 5%, 10%, or 13.5%; the atomic percentage of W in the MoS2-WS2-based composite film is 13.0-27.3%, specifically 13.0%, 18.5%, 25.9%, or 27.3%; the atomic percentage of Mo in the MoS2-WS2-based composite film is 14.4-38.4%, specifically 14.0%, 21.8%, 27.1%, or 38.4%; the MoS2-WS2-based composite film contains a balance of S and impurity elements; the impurity elements include C and / or O.

[0030] The present invention also provides a MoS2-WS2 based composite film prepared according to the preparation method described above, comprising MoS2 and WS2, or comprising MoS2, WS2 and Ti.

[0031] In this invention, based on atomic percentage, the MoS2-WS2-based composite film contains 0-13.5% Ti, specifically 0, 2%, 5%, 10%, or 13.5%; the MoS2-WS2-based composite film contains 13.0-27.3% W, specifically 13.0%, 18.5%, 25.9%, or 27.3%; the MoS2-WS2-based composite film contains 14.4-38.4% Mo, specifically 14.0%, 21.8%, 27.4%, or 38.4%; the MoS2-WS2-based composite film contains the balance S and impurity elements; the impurity elements include C and / or O; the thickness of the MoS2-WS2-based composite film can be 1-2 μm, specifically 1.1 μm, 1.4 μm, 1.5 μm, 1.6 μm, or 1.8 μm.

[0032] In this invention, the MoS2-WS2 based composite film may further include a Ti transition layer between itself and the substrate material. The thickness of the Ti transition layer may be 48~52nm, specifically 50nm.

[0033] In this invention, the average coefficient of friction of the MoS2-WS2-based composite film in vacuum can be <0.04, specifically 0.035, 0.027, or 0.020; the wear resistance life of the MoS2-WS2-based composite film in vacuum can be >10. 5 The rotation can be specifically 1.86 × 10⁻⁶. 5 Turn, 1.33×10 5 Turn, 1.24×10 5 Turn or 1.12×10 5 The MoS2-WS2-based composite film provided by this invention still exhibits good tribological properties after atomic oxygen irradiation.

[0034] This invention also provides the application of the MoS2-WS2 based composite film described in the above technical solution as a space lubrication material.

[0035] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0036] The present invention uses EDS testing of scanning electron microscopes to determine the atomic percentage of each element in composite films prepared in the examples and comparative examples.

[0037] Example 1 Using 9Cr18 steel as the substrate material, the substrate material was ultrasonically cleaned with ethanol and petroleum ether for 15 minutes in sequence, and the cleaned substrate material was placed into the sample holder in the coating chamber. A vacuum pump was used to evacuate the coating chamber. When the chamber pressure was 3.0 × 10⁻⁶, the pressure was reduced to 3.0 × 10⁻⁶. -3 At Pa, 30 SCCM of argon gas is introduced into the chamber, and a negative bias voltage of 400V is applied to the substrate material to remove contaminants from the substrate surface. Using unbalanced magnetron sputtering technology, a Ti target with a purity of 99.99% was used as the target material, argon gas was used as the sputtering gas source, and a negative bias voltage was applied to the substrate material to deposit a Ti transition layer with a thickness of 50 nm on the substrate material surface. The deposition parameters were as follows: Ti target current was 0.1 A, argon gas flow rate was 30 SCCM, negative bias voltage was 100 V, and deposition time was 10 min. A MoS2-WS2 composite film (containing titanium) was deposited on the surface of a Ti transition layer using a MoS2 target with a purity of 99.99%, a WS2 target with a purity of 99.99%, and a metallic Ti target with a purity of 99.99%. The process parameters were as follows: MoS2 target power was 600W, WS2 target power was 600W, metallic Ti target current was 0.2A, argon flow rate was 70SCCM, negative bias voltage was 20V, and deposition time was 110min. The deposition was stopped, the bias voltage and sputtering power supply were turned off, the gas supply was stopped, and the gas was evacuated for another 120min to obtain a material containing a MoS2-WS2 composite film. On an atomic percentage basis, the MoS2-WS2 composite film contained 13.5% Ti, 18.5% W, 21.8% Mo, and the balance being S and impurity elements C and O.

[0038] Example 2 The material containing MoS2-WS2 composite films was prepared according to the method in Example 1, except that a metal Ti target was not used when depositing the MoS2-WS2 composite film on the Ti transition layer surface, and the resulting MoS2-WS2 composite film did not contain titanium. The specific preparation process is as follows: Using 9Cr18 steel as the substrate material, the substrate material was ultrasonically cleaned with ethanol and petroleum ether for 15 minutes in sequence, and the cleaned substrate material was placed into the sample holder in the coating chamber. A vacuum pump was used to evacuate the coating chamber. When the chamber pressure was 3.0 × 10⁻⁶, the pressure was reduced to 3.0 × 10⁻⁶. -3 At Pa, 30 SCCM of argon gas is introduced into the chamber, and a negative bias voltage of 400V is applied to the substrate material to remove contaminants from the substrate surface. Using unbalanced magnetron sputtering technology, a Ti transition layer was deposited on the surface of the substrate material with a Ti target of 99.99% purity and argon gas as the sputtering gas source. A negative bias voltage was applied to the substrate material. The deposition parameters were as follows: Ti target current of 0.1A, argon gas flow rate of 30SCCM, negative bias voltage of 100V, and deposition time of 10min. A MoS2-WS2 composite film (excluding titanium) was deposited on the surface of a Ti transition layer using a MoS2 target with a purity of 99.99% and a WS2 target with a purity of 99.99%. The process parameters were as follows: MoS2 target power 600W, WS2 target power 600W, argon flow rate 70SCCM, negative bias voltage 20V, and deposition time 110min. The deposition was stopped, the bias voltage and sputtering power supply were turned off, the gas supply was stopped, and the gas was evacuated for another 120min to obtain a material containing the MoS2-WS2 composite film. On an atomic percentage basis, the MoS2-WS2 composite film contained 0% Ti, 0.25.9% W, 27.4% Mo, and the balance S and impurity elements C and O.

[0039] Example 3 Materials containing MoS2-WS2 composite films were prepared according to the method of Example 2, except that the parameters for depositing the MoS2-WS2 composite film were: MoS2 target power of 600W, WS2 target power of 200W, argon flow rate of 70SCCM, negative bias voltage of 20V, and deposition time of 110min.

[0040] On an atomic percentage basis, the obtained MoS2-WS2 composite film contains 0% Ti, 13.0% W, 38.4% Mo, and the balance S and impurity elements C and O.

[0041] Example 4 Materials containing MoS2-WS2 composite films were prepared according to the method of Example 2, except that the parameters for depositing the MoS2-WS2 composite film were: MoS2 target power of 200W, WS2 target power of 600W, argon flow rate of 70SCCM, negative bias voltage of 20V, and deposition time of 110min.

[0042] On an atomic percentage basis, the obtained MoS2-WS2 composite film contains 0% Ti, 27.3% W, 14.0% Mo, and the balance S and impurity elements C and O.

[0043] Comparative Example 1 The material containing MoS2-WS2 composite film was prepared according to the method in Example 2, except that a MoS2 film was deposited on the surface of the Ti transition layer; the specific preparation process is as follows: Using 9Cr18 steel as the substrate material, the substrate material was ultrasonically cleaned with ethanol and petroleum ether for 15 minutes in sequence, and the cleaned substrate material was placed into the sample holder in the coating chamber. A vacuum pump was used to evacuate the coating chamber. When the chamber pressure was 3.0 × 10⁻⁶, the pressure was reduced to 3.0 × 10⁻⁶. -3 At Pa, 30 SCCM of argon gas is introduced into the chamber, and a negative bias voltage of 400V is applied to the substrate material to remove contaminants from the substrate surface. Using unbalanced magnetron sputtering technology, a Ti transition layer was deposited on the surface of the substrate material with a Ti target of 99.99% purity and argon gas as the sputtering gas source. A negative bias voltage was applied to the substrate material. The deposition parameters were as follows: Ti target current of 0.1A, argon gas flow rate of 30SCCM, negative bias voltage of 100V, and deposition time of 10min. A MoS2 thin film was deposited on the surface of a Ti transition layer using a MoS2 target with a purity of 99.99%. The process parameters were as follows: MoS2 target power of 600W, argon flow rate of 70SCCM, negative bias voltage of 20V, and deposition time of 110min. The deposition was stopped, the bias voltage and sputtering power supply were turned off, the gas supply was stopped, and the gas was evacuated for another 120min to obtain a material containing a MoS2 thin film. The MoS2 thin film contained 37.4% Mo and the balance S and impurity elements C and O, based on atomic percentage.

[0044] Comparative Example 2 The material containing MoS2-WS2 composite film was prepared according to the method of Example 2, except that a WS2 film was deposited on the surface of the Ti transition layer; the specific preparation process is as follows: Using 9Cr18 steel as the substrate material, the substrate material was ultrasonically cleaned with ethanol and petroleum ether for 15 minutes in sequence, and the cleaned substrate material was placed into the sample holder in the coating chamber. A vacuum pump was used to evacuate the coating chamber. When the chamber pressure was 3.0 × 10⁻⁶, the pressure was reduced to 3.0 × 10⁻⁶. -3 At Pa, 30 SCCM of argon gas is introduced into the chamber, and a negative bias voltage of 400V is applied to the substrate material to remove contaminants from the substrate surface. Using unbalanced magnetron sputtering technology, a Ti transition layer was deposited on the surface of the substrate material with a Ti target of 99.99% purity and argon gas as the sputtering gas source. A negative bias voltage was applied to the substrate material. The deposition parameters were as follows: Ti target current of 0.1A, argon gas flow rate of 30SCCM, negative bias voltage of 100V, and deposition time of 10min. A WS2 thin film was deposited on the surface of a Ti transition layer using a WS2 target with a purity of 99.99%. The process parameters were as follows: WS2 target power of 600W, argon flow rate of 70SCCM, negative bias voltage of 20V, and deposition time of 110min. The deposition was stopped, the bias voltage and sputtering power supply were turned off, the gas supply was stopped, and the gas was evacuated for another 120min to obtain a material containing a WS2 thin film. The WS2 thin film contained 41.1% W and the balance of S and impurity elements C and O, based on atomic percentage.

[0045] The cross-sectional morphology of the MoS2-WS2 composite films prepared in Examples 1-4 was observed using field emission scanning electron microscopy (SEM), and the obtained SEM images are shown below. Figures 1-4 As shown, where Figure 1 This is the SEM image of Example 1. Figure 2 This is the SEM image of Example 2. Figure 3 This is the SEM image of Example 3. Figure 4 The image shown is a SEM image of Example 4. The thicknesses of the Ti transition layer and the MoS2-WS2 composite film obtained from the SEM images are listed in Table 1.

[0046] Table 1. Thicknesses of the Ti transition layer and MoS2-WS2 composite films prepared in Examples 1-4

[0047] The vacuum tribological properties of the films prepared in Examples 1-4 and Comparative Examples 1-2 were tested using a ball-disc friction testing machine. The test conditions were: the paired balls were 9Cr18 steel balls with a diameter of Φ6mm; the load was 5N; and the rotational speed was 500r / min. The obtained friction curves are shown below. Figure 5 and Figure 6 As shown, where Figure 5 The friction curves for Examples 1-4 are shown in a vacuum environment. Figure 6 The friction curves for Comparative Examples 1 and 2 under vacuum conditions are shown in Table 2. The average friction coefficient, wear life, and wear rate obtained from the friction curves are listed in Table 2.

[0048] Table 2. Tribological properties of the films prepared in Examples 1-4 and Comparative Examples 1-2

[0049] Combine Table 2 and Figures 5-6 It can be seen that the MoS2-WS2 composite film provided by the present invention has a low coefficient of friction, a small wear rate, and a long wear resistance life in a vacuum environment.

[0050] The MoS2-WS2 composite films prepared in Examples 1-4 were subjected to atomic oxygen irradiation under the following conditions: 2 × 10⁻⁶. 20 atoms / cm 2 The thin film irradiated with atomic oxygen was subjected to vacuum tribological property testing. The test conditions were: the paired spheres were 9Cr18 steel balls with a diameter of Φ6mm, the load was 5N, and the rotational speed was 500r / min. The obtained friction curves are shown below. Figure 7 As shown in the figure. The average friction coefficient, wear life, and wear rate obtained from the friction curves are listed in Table 3.

[0051] Table 3. Tribological properties of MoS2-WS2 composite films in Examples 1-4 after atomic oxygen irradiation.

[0052] Combined with Table 3 and Figure 7 It can be seen that the MoS2-WS2 composite film provided by the present invention has good resistance to atomic oxygen irradiation and still has good tribological properties after atomic oxygen irradiation.

[0053] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a MoS2-WS2 based composite thin film, characterized in that, Includes the following steps: After ion bombardment cleaning of the substrate material, unbalanced magnetron sputtering is performed using MoS2 and WS2 targets, or MoS2, WS2 and Ti targets, to form a MoS2-WS2 based composite film. The MoS2-WS2 based composite film contains 0~13.5% Ti, 13.0~27.3% W, 14.4~38.4% Mo and the balance S and impurity elements, based on atomic percentage. The conditions for the unbalanced magnetron sputtering include: MoS2 target power of 200~600W, WS2 target power of 200~600W, Ti target current of 0~0.2A, argon flow rate of 50~70SCCM, negative bias voltage of 18~22V, and deposition time of 100~120min.

2. The preparation method according to claim 1, characterized in that, The thickness of the MoS2-WS2 based composite film is 1~2μm.

3. The preparation method according to claim 1, characterized in that, A Ti transition layer is deposited between the substrate and the MoS2-WS2-based composite film; The conditions for depositing the Ti transition layer include: using a metallic Ti target as the target material, argon gas as the sputtering gas source, a metallic Ti target current of 0.1~0.2A, an argon gas flow rate of 30~50SCCM, a negative bias voltage of 80~120V, and a deposition time of 10~15min.

4. The preparation method according to claim 3, characterized in that, The thickness of the Ti transition layer is 48~52nm.

5. The preparation method according to claim 1, characterized in that, The ion bombardment cleaning includes the following steps: evacuating the coating chamber using a vacuum pump until the chamber pressure reaches 3.0 × 10⁻⁶. -3 When the pressure is below 1 Pa, 28-32 SCCM of argon gas is introduced into the chamber, while a negative bias voltage of 380-420V is applied to the substrate material.

6. The preparation method according to claim 1 or 5, characterized in that, The substrate comprises 9Cr18 steel or silicon wafer.

7. The MoS2-WS2-based composite thin film prepared according to any one of claims 1 to 6, characterized in that, It includes MoS2 and WS2, or includes MoS2, WS2 and Ti; the MoS2-WS2 based composite film contains 0~13.5% Ti, 13.0~27.3% W, 14.4~38.4% Mo and the balance S and impurity elements, by atomic percentage.

8. The MoS2-WS2-based composite thin film according to claim 7, characterized in that, The MoS2-WS2 based composite film also includes a Ti transition layer between itself and the substrate material.

9. The MoS2-WS2-based composite thin film according to claim 8, characterized in that, The thickness of the MoS2-WS2-based composite film is 1~2μm; the thickness of the Ti transition layer is 48~52nm; The MoS2-WS2-based composite film exhibits an average coefficient of friction of <0.04 in vacuum and a wear resistance life of >10. 5 change.

10. The application of the MoS2-WS2 based composite film according to any one of claims 7 to 9 as a space lubricant.

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