Low-friction high-wear-resistant solid lubricating film, and preparation method and application thereof

Abstract

The application provides a low-friction high-wear-resistance solid lubricating film, which comprises a substrate, a transition layer and a functional layer arranged in sequence from bottom to top; the transition layer comprises a bottom layer, an intermediate layer and an upper layer in sequence from bottom to top; the bottom layer is composed of Ta; the intermediate layer is composed of Ta and MoS2; the upper layer is composed of Ta, Pb and MoS2; and the functional layer is composed of Ta, Pb and MoS2. The transition layer of the application adopts a gradient structure, and the thermal expansion coefficients of Ta, Ta-MoS2 and Ta-Pb-MoS2 are changed layer by layer, which is more conducive to reducing stress concentration, thereby avoiding cracking and peeling of the solid lubricating film on the substrate and improving the bonding strength with the substrate; the functional layer has the functions of friction reduction and wear resistance, is based on MoS2, combines the high hardness of Ta metal, improves the wear resistance, and further reduces the friction coefficient of the soft metal Pb, thereby greatly improving the service performance and service life of the solid lubricating film.

Description

Technical Field

[0001] This invention belongs to the field of solid lubricating film technology, specifically relating to a low-friction, high-wear-resistant solid lubricating film, its preparation method, and its application. Background Technology

[0002] Spacecraft are mostly operated under conditions of long-term on-orbit operation and rapid response, making regular inspections and timely maintenance of spacecraft platforms and weapon systems difficult to carry out. This places extremely high demands on the system's operational accuracy, lifespan, and reliability. Spacecraft contain numerous load-bearing and moving components that enable the deployment, alignment, docking, and separation of spacecraft parts / mechanisms. Therefore, lubrication of these moving components, which operate in a high-vacuum environment for extended periods, is necessary to improve system operational accuracy and reliability. However, traditional grease lubrication methods used on Earth are not suitable for high-vacuum environments because lubricating greases are prone to evaporation, decomposition, or cross-linking in high vacuum, which can damage or even malfunction electronic components throughout the cabin.

[0003] For lubrication of moving parts in high vacuum environments, solid lubricating films are commonly used to reduce friction and wear between transmission components. These films, with a thickness of 1–2 μm, reduce friction and wear. Currently, the most typical method is to prepare molybdenum disulfide (MoD) films using PECVD (plasma-assisted chemical vapor deposition). These films have a hexagonal symmetric structure, exhibiting a typical layered structure. The layers are bonded by van der Waals forces, resulting in weak coupling and easy layer separation, leading to a low coefficient of friction in high vacuum environments. Although PECVD-prepared MoD films have a low coefficient of friction and good lubrication performance in high vacuum environments, their thinness (around 1 μm) and the fact that their lubrication mechanism involves interlayer peeling—a sacrificial friction reduction method—make them less effective as solid lubricating films. Furthermore, the difference in thermal expansion coefficients between the MoD film and the substrate leads to insufficient adhesion and a tendency for unpredictable detachment. Therefore, improving wear resistance and bonding strength with the substrate while maintaining the friction-reducing properties of solid lubricating films remains a critical technical challenge in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a low-friction, high-wear-resistant solid lubricating film, its preparation method, and its applications. The solid lubricating film provided by this invention possesses excellent friction-reducing and wear-resistant properties, and exhibits high bonding strength with the substrate.

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

[0006] This invention provides a low-friction, high-wear-resistant solid lubricating film, comprising a substrate, a transition layer, and a functional layer arranged sequentially from bottom to top;

[0007] The transition layer comprises, from bottom to top, a bottom layer, a middle layer, and an upper layer;

[0008] The bottom layer is composed of Ta; the middle layer is composed of Ta and MoS2; the top layer is composed of Ta, Pb and MoS2.

[0009] The functional layer is composed of Ta, Pb and MoS2.

[0010] Preferably, the substrate is a single-crystal silicon wafer or a stainless steel substrate.

[0011] Preferably, the thickness of the bottom layer is 0.05–0.10 μm; the thickness of the middle layer is 0.15–0.25 μm; and the thickness of the top layer is 0.05–0.10 μm.

[0012] Preferably, the thickness of the functional layer is 1.0 to 1.5 μm.

[0013] Preferably, based on the total atomic percentage of Ta, Pb and Mo in the functional layer being 100%, the functional layer contains 5% to 15% Ta, 15% to 25% Pb and 65% to 75% Mo.

[0014] The present invention also provides a method for preparing the low-friction, high-wear-resistant solid lubricating film described in the above technical solution, comprising the following steps:

[0015] (1) A transition layer is deposited on the surface of the substrate by magnetron sputtering;

[0016] (2) A functional layer is deposited on the transition layer obtained in step (1) by magnetron sputtering to obtain a low-friction, high-wear-resistant solid lubricating film.

[0017] Preferably, step (1) further includes cleaning and etching the substrate sequentially before use.

[0018] Preferably, the operation of depositing a transition layer on the surface of the substrate using magnetron sputtering in step (1) includes the following steps:

[0019] 1) A bottom layer is deposited on the surface of the substrate using magnetron sputtering; the process parameters of the magnetron sputtering method are: inert gas flow rate 10-20 sccm, negative bias voltage linearly decreasing from -250V to -60V, Ta target current linearly increasing from 1.5A to 3.0A, linear change time 5-10 min, sputtering time 5-10 min.

[0020] 2) An intermediate layer is deposited on the surface of the bottom layer obtained in step 1) using magnetron sputtering; the process parameters of the magnetron sputtering method are: inert gas flow rate 10-20 sccm, negative bias voltage -60V, the current of the Ta target material is linearly reduced from 3.0A to 2.5A, the current of the MoS2 target material is linearly increased from 0.2A to 0.4A, the linear change time is 5-10 min, and the sputtering time is 5-10 min.

[0021] 3) A top layer is deposited on the surface of the intermediate layer obtained in step 2) using magnetron sputtering to obtain a transition layer; the process parameters of the magnetron sputtering method are: inert gas flow rate 10-20 sccm, negative bias voltage -50V to -60V, the current of the Ta target material is linearly reduced from 2.5A to 0.2A, the current of the MoS2 target material is linearly increased from 0.4A to 0.8A, the current of the Pb target material is linearly increased from 0A to 0.2A, the linear change time is 5-10 min, and the sputtering time is 5-10 min.

[0022] Preferably, the process parameters of the magnetron sputtering method in step (2) are: inert gas flow rate 10-20 sccm, substrate negative bias voltage -50V to -60V, Ta target current 0.15-0.3A, MoS2 target current 0.8-1.2A, Pb target current 0.15-0.3A, and sputtering time 200-240min.

[0023] The present invention also provides the application of the low-friction, high-wear-resistant solid lubricating film described in the above technical solution or the low-friction, high-wear-resistant solid lubricating film prepared by the preparation method described in the above technical solution in a vacuum environment.

[0024] This invention provides a low-friction, high-wear-resistant solid lubricating film, comprising a substrate, a transition layer, and a functional layer arranged sequentially from bottom to top. The transition layer comprises a bottom layer, an intermediate layer, and a top layer from bottom to top. The bottom layer is composed of Ta; the intermediate layer is composed of Ta and MoS2; the top layer is composed of Ta, Pb, and MoS2; and the functional layer is composed of Ta, Pb, and MoS2. The transition layer of this invention adopts a gradient structure, changing the coefficient of thermal expansion layer by layer through Ta, Ta-MoS2, and Ta-Pb-MoS2, which is more conducive to reducing stress concentration, thereby preventing the solid lubricating film from cracking and peeling off on the substrate and improving the bonding strength with the substrate. The functional layer has friction-reducing and wear-resistant functions. Based on MoS2, it combines the high hardness of Ta metal to improve wear resistance, while the soft metal Pb further reduces the coefficient of friction. This allows the solid lubricating film to greatly improve service performance and service life when applied to the surfaces of various components in vacuum environments. Experimental results show that the solid lubricating film provided by this invention has a bonding strength of up to 22N, which is an improvement of about 47%; the coefficient of friction remains stable below 0.04; and after 500,000 revolutions, there are still no signs of failure. Attached Figure Description

[0025] Figure 1 This is a schematic diagram showing the positional relationship of each target material in Example 1;

[0026] Figure 2 The surface morphology and elemental content of the low-friction, high-wear-resistant solid lubricant film prepared in Example 2 are shown.

[0027] Figure 3 The elemental distribution diagram of the low-friction, high-wear-resistant solid lubricant film prepared in Example 2 is shown.

[0028] Figure 4 This is a TEM image of the low-friction, high-wear-resistant solid lubricant film prepared in Example 2;

[0029] Figure 5 This is a microscopic cross-sectional view of the low-friction, high-wear-resistant solid lubricating film prepared in Example 2;

[0030] Figure 6 The friction coefficient diagram is shown for the low-friction, high-wear-resistant solid lubricating film prepared in Example 2.

[0031] Figure 7 The image shows the three-dimensional morphology of the low-friction, high-wear-resistant solid lubricant film prepared in Example 2 after 500,000 revolutions of friction in a vacuum environment.

[0032] Figure 8 This is a test diagram of the bonding strength of the low-friction, high-wear-resistant solid lubricant film prepared in Example 2;

[0033] Figure 9 The surface morphology of the low-friction, high-wear-resistant solid lubricating film prepared in Example 3 is shown. Detailed Implementation

[0034] This invention provides a low-friction, high-wear-resistant solid lubricating film, comprising a substrate, a transition layer, and a functional layer arranged sequentially from bottom to top;

[0035] The transition layer comprises, from bottom to top, a bottom layer, a middle layer, and an upper layer;

[0036] The bottom layer is composed of Ta; the middle layer is composed of Ta and MoS2; the top layer is composed of Ta, Pb and MoS2.

[0037] The functional layer is composed of Ta, Pb and MoS2.

[0038] In this invention, the low-friction, high-wear-resistant solid lubricating film includes a substrate. Preferably, the substrate is a monocrystalline silicon wafer or a stainless steel substrate; the monocrystalline silicon wafer is preferably a high-grade monocrystalline silicon wafer; the stainless steel substrate is preferably gear steel with a hardness of not less than 25 HRC, obtained through sandpaper polishing and liquid polishing. This invention does not have a specific limitation on the source of the substrate; commercially available products well-known to those skilled in the art can be used. This invention does not have a specific limitation on the thickness of the substrate; it can be adjusted as needed.

[0039] In this invention, the low-friction, high-wear-resistant solid lubricating film further includes a transition layer disposed on the upper surface of the substrate; the transition layer comprises, from bottom to top, a bottom layer, an intermediate layer, and an upper layer. The transition layer of this invention adopts a gradient structure, changing the coefficient of thermal expansion layer by layer through Ta, Ta-MoS2, and Ta-Pb-MoS2, which is more conducive to reducing stress concentration, thereby preventing the solid lubricating film from cracking and peeling off on the substrate, and improving the bonding strength with the substrate.

[0040] In this invention, the underlying layer is composed of Ta.

[0041] In this invention, the intermediate layer is composed of Ta and MoS2; the atomic ratio of Mo in Ta and MoS2 is preferably 1:2.

[0042] In this invention, the upper layer is composed of Ta, Pb and MoS2; the atomic ratio of Mo in Ta, Pb and MoS2 is preferably 1:2:6.

[0043] In this invention, along the direction from the bottom layer to the top layer, the Ta content in the intermediate layer gradually decreases while the MoS2 content gradually increases; along the direction from the bottom layer to the top layer, the Ta content in the top layer gradually decreases while the MoS2 content remains unchanged and the Pb content gradually increases.

[0044] In this invention, the thickness of the bottom layer is preferably 0.05 to 0.10 μm; the thickness of the middle layer is preferably 0.15 to 0.25 μm; and the thickness of the top layer is preferably 0.05 to 0.10 μm.

[0045] In this invention, the low-friction, high-wear-resistant solid lubricating film further includes a functional layer disposed on the upper surface of the transition layer; the functional layer is composed of Ta, Pb, and MoS2; based on the total atomic percentage of Ta, Pb, and Mo in the functional layer being 100%, Ta is preferably 5%–15%, Pb is preferably 15%–25%, and Mo is preferably 65%–75%, more preferably Ta is 7%–10%, Pb is 18%–20%, and Mo is 70%–75%. In this invention, the functional layer has friction-reducing and wear-resistant functions. Using MoS2 as a base, it combines the high hardness of Ta metal to improve wear resistance, while the soft metal Pb further reduces the coefficient of friction, thus greatly improving the service performance and service life of the solid lubricating film when applied to the surfaces of various components in a vacuum environment.

[0046] In this invention, the thickness of the functional layer is preferably 1.0 to 1.5 μm.

[0047] The transition layer of this invention adopts a gradient structure, which changes the coefficient of thermal expansion layer by layer through Ta, Ta-MoS2, and Ta-Pb-MoS2, which is more conducive to reducing stress concentration, thereby avoiding cracking and peeling of the solid lubricating film on the substrate and improving the bonding strength with the substrate. The functional layer has friction reduction and wear resistance functions. Based on MoS2, it combines the high hardness of Ta metal to improve wear resistance, and the soft metal Pb further reduces the coefficient of friction. This makes the solid lubricating film greatly improve the service performance and service life when applied to the surface of various components in a vacuum environment.

[0048] The present invention also provides a method for preparing the low-friction, high-wear-resistant solid lubricating film described in the above technical solution, comprising the following steps:

[0049] (1) A transition layer is deposited on the surface of the substrate by magnetron sputtering;

[0050] (2) A functional layer is deposited on the transition layer obtained in step (1) by magnetron sputtering to obtain a low-friction, high-wear-resistant solid lubricating film.

[0051] This invention uses magnetron sputtering to deposit a transition layer on the surface of a substrate.

[0052] In this invention, the substrate is preferably further subjected to sequential cleaning and etching before use.

[0053] In this invention, the cleaning agent used for cleaning is preferably an organic solvent, more preferably ethanol or acetone; the cleaning is preferably performed in an ultrasonic cleaner; and the cleaning time is preferably ≥20 minutes. This invention does not have a specific limitation on the model of the ultrasonic cleaner; any instrument or equipment well known to those skilled in the art can be used. This invention can remove oil and adsorbed impurities that may be present on the substrate surface when cleaning the substrate.

[0054] In this invention, the etching is preferably performed by bombarding the substrate with argon plasma; the purity of the argon gas is preferably 99.999%; the flow rate of the argon gas is preferably 20-30 sccm; the negative bias voltage during etching is preferably -600V to -700V; and the etching time is preferably 20-30 minutes. This invention increases the roughness of the substrate by etching, thereby improving the bonding strength between the substrate and the thin film.

[0055] In this invention, the operation of depositing a transition layer on the surface of the substrate using magnetron sputtering preferably includes the following steps:

[0056] 1) A bottom layer is deposited on the surface of the substrate using magnetron sputtering; the process parameters of the magnetron sputtering method are: inert gas flow rate 10-20 sccm, negative bias voltage linearly decreasing from -250V to -60V, Ta target current linearly increasing from 1.5A to 3.0A, linear change time 5-10 min, sputtering time 5-10 min.

[0057] 2) An intermediate layer is deposited on the surface of the bottom layer obtained in step 1) using magnetron sputtering; the process parameters of the magnetron sputtering method are: inert gas flow rate 10-20 sccm, negative bias voltage -60V, the current of the Ta target material is linearly reduced from 3.0A to 2.5A, the current of the MoS2 target material is linearly increased from 0.2A to 0.4A, the linear change time is 5-10 min, and the sputtering time is 5-10 min.

[0058] 3) A top layer is deposited on the surface of the intermediate layer obtained in step 2) using magnetron sputtering to obtain a transition layer; the process parameters of the magnetron sputtering method are: inert gas flow rate 10-20 sccm, negative bias voltage -50V to -60V, the current of the Ta target material is linearly reduced from 2.5A to 0.2A, the current of the MoS2 target material is linearly increased from 0.4A to 0.8A, the current of the Pb target material is linearly increased from 0A to 0.2A, the linear change time is 5-10 min, and the sputtering time is 5-10 min.

[0059] The present invention preferably employs magnetron sputtering to deposit an underlayer on the surface of the substrate.

[0060] In this invention, argon plasma is preferably used to clean the inside of the magnetron sputtering equipment and each target material before depositing the bottom layer; the flow rate of the argon gas is preferably 20-30 sccm; the negative bias voltage during cleaning is preferably -120V to -150V; and the cleaning time is preferably 20-30 minutes.

[0061] In this invention, the preferred process parameters for the magnetron sputtering method are: inert gas flow rate of 10-20 sccm, negative bias voltage linearly decreasing from -250V to -60V, Ta target current linearly increasing from 1.5A to 3.0A, linear change time of 5-10 min, and sputtering time of 5-10 min; more preferably, the inert gas flow rate is 10-16 sccm, negative bias voltage linearly decreasing from -250V to -60V, Ta target current linearly increasing from 1.5A to 3.0A, linear change time of 5-8 min, and sputtering time of 8-10 min.

[0062] In this invention, the inert gas is preferably argon or helium.

[0063] After obtaining the bottom layer, the present invention preferably uses magnetron sputtering to deposit an intermediate layer on the surface of the bottom layer.

[0064] In this invention, the preferred process parameters for the magnetron sputtering method are: inert gas flow rate 10-20 sccm, negative bias voltage -60V, current of the Ta target linearly decreasing from 3.0A to 2.5A, current of the MoS2 target linearly increasing from 0.2A to 0.4A, linear change time 5-10 min, and sputtering time 5-10 min; more preferably: inert gas flow rate 10-16 sccm, negative bias voltage -60V, current of the Ta target linearly decreasing from 3.0A to 2.5A, current of the MoS2 target linearly increasing from 0.2A to 0.4A, linear change time 5-8 min, and sputtering time 8-10 min.

[0065] In this invention, the inert gas is preferably argon or helium.

[0066] After obtaining the intermediate layer, the present invention preferably uses magnetron sputtering to deposit an upper layer on the surface of the intermediate layer to obtain a transition layer.

[0067] In this invention, the preferred process parameters for the magnetron sputtering method are: inert gas flow rate 10-20 sccm, negative bias voltage -50V to -60V, current of Ta target linearly decreasing from 2.5A to 0.2A, current of MoS2 target linearly increasing from 0.4A to 0.8A, current of Pb target linearly increasing from 0A to 0.2A, with a linear change time of 5-10 min, and sputtering time of 5-10 min; more preferably: inert gas flow rate 10-16 sccm, negative bias voltage -55V to -60V, current of Ta target linearly decreasing from 2.5A to 0.2A, current of MoS2 target linearly increasing from 0.4A to 0.8A, current of Pb target linearly increasing from 0A to 0.2A, with a linear change time of 5-8 min, and sputtering time of 8-10 min.

[0068] In this invention, the inert gas is preferably argon or helium.

[0069] This invention can further improve the bonding strength between the substrate and the thin film by controlling the process parameters of the magnetron sputtering method for each layer of the transition layer.

[0070] After obtaining the transition layer, the present invention uses magnetron sputtering to deposit a functional layer on the transition layer to obtain a low-friction, high-wear-resistant solid lubricating film.

[0071] In this invention, the preferred process parameters for the magnetron sputtering method are: inert gas flow rate 10–20 sccm, substrate negative bias voltage -50V to -60V, Ta target current 0.15–0.3A, MoS2 target current 0.8–1.2A, Pb target current 0.15–0.3A, and sputtering time 200–240 min; more preferably: inert gas flow rate 10–15 sccm, substrate negative bias voltage -55V to -60V, Ta target current 0.15–0.2A, MoS2 target current 0.8–1.0A, Pb target current 0.15–0.2A, and sputtering time 200–220 min. This invention, by controlling the process parameters of the magnetron sputtering method, can further improve the friction reduction and wear resistance of the thin film.

[0072] In this invention, the inert gas is preferably argon or helium.

[0073] In this invention, the purity of the inert gas is preferably 99.999%, and the purity of the Ta target, MoS2 target and Pb target is preferably >99.95% independently.

[0074] The present invention does not have any special limitation on the source of the above-mentioned raw materials; commercially available products known to those skilled in the art can be used.

[0075] The preparation method provided by this invention is simple.

[0076] To address the issues of poor stability and easy failure of transmission components used in vacuum environments, this invention employs a Ta / Ta-MoS2 / Ta-Pb-MoS2 gradient transition layer and a Ta-Pb-MoS2 functional friction-reducing and wear-resistant layer. The thermal expansion coefficient is gradually changed layer by layer from Ta to Ta-MoS2 to Ta-Pb-MoS2, and the preparation method utilizes a current-controlled linear decrease or increase process. This indicates that the elemental changes between layers are completed gradually, rather than through direct layer-to-layer composite, which is more conducive to reducing stress concentration. The friction-reducing and wear-resistant functional layer prepared in this invention includes Ta-Pb-MoS2, in which most of the molybdenum disulfide exists in an amorphous state. This locally disrupts the layered structure without affecting the friction coefficient, but reduces the number of atoms peeled off from each layer. Simultaneously, Ta, as a hard metal, provides strength and wear resistance, while the soft metal Pb further reduces the friction coefficient.

[0077] The film prepared by the independently designed film structure of this invention exhibits excellent performance in a vacuum environment, demonstrating higher bonding strength and longer wear resistance compared to traditional films. Specifically, compared to the bonding strength of ordinary films (around 15N), the solid lubricating film prepared by this invention boasts a bonding strength as high as 22N, an improvement of approximately 47%; the coefficient of friction remains stably below 0.04; and unlike ordinary films where the coefficient of friction increases sharply after about 100,000 revolutions, this film showed no signs of failure even after 500,000 revolutions.

[0078] The present invention also provides the application of the low-friction, high-wear-resistant solid lubricating film described in the above technical solution or the low-friction, high-wear-resistant solid lubricating film prepared by the preparation method described in the above technical solution in a vacuum environment.

[0079] The present invention does not impose any special limitations on the operation of the low-friction, high-wear-resistant solid lubricating film in a vacuum environment; any operation familiar to those skilled in the art can be used.

[0080] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0081] Example 1

[0082] The low-friction, high-wear-resistant solid lubricating film consists of a substrate, a transition layer, and a functional layer arranged sequentially from bottom to top.

[0083] The transition layer consists of a bottom layer, a middle layer, and an upper layer from bottom to top.

[0084] The bottom layer is composed of Ta; the middle layer is composed of Ta and MoS2, with the ratio of Mo atoms in Ta and MoS2 being 1:2; the top layer is composed of Ta, Pb and MoS2, with the ratio of Mo atoms in Ta, Pb and MoS2 being 1:2:6.

[0085] The functional layer is composed of Ta, Pb and MoS2;

[0086] The substrate is gear steel with a hardness of not less than 25HRC, which has been sanded and liquid polished.

[0087] Along the direction from the bottom layer to the top layer, the Ta content in the intermediate layer gradually decreases, while the MoS2 content gradually increases; along the direction from the bottom layer to the top layer, the Ta content in the top layer gradually decreases, the MoS2 content remains unchanged, while the Pb content gradually increases.

[0088] The thickness of the bottom layer is 0.05 μm; the thickness of the middle layer is 0.15 μm; and the thickness of the top layer is 0.05 μm.

[0089] With the total atomic percentage of Ta, Pb and Mo in the functional layer being 100%, the functional layer contains 12% Ta, 23% Pb, and 65% Mo in MoS2;

[0090] The thickness of the functional layer is 1.28 μm;

[0091] The preparation method of the low-friction, high-wear-resistant solid lubricating film is as follows:

[0092] (1) The substrate was ultrasonically cleaned in ethanol for 20 min, and then etched by bombarding the substrate with argon plasma for 30 min to obtain the pretreated substrate; wherein the flow rate of argon was 30 sccm and the negative bias voltage was -700V.

[0093] (2) Argon plasma was used to clean the inside of the magnetron sputtering equipment and each target material. The equipment was a TeerUDP 650 closed-field unbalanced magnetron sputtering equipment. The cleaning process parameters were: argon flow rate 20 sccm, bias voltage 150V, and cleaning time 20 min.

[0094] (3) A bottom layer was deposited on the surface of the pretreated substrate obtained in step (1) using magnetron sputtering. The process parameters were: argon flow rate 10 sccm, negative bias voltage linearly decreased from -250V to -60V, Ta target current linearly increased from 1.5A to 3.0A, linear change time 5 min, and sputtering time 10 min.

[0095] (4) An intermediate layer is deposited on the surface of the bottom layer obtained in step (3) using magnetron sputtering. The process parameters are: argon flow rate 10 sccm, negative bias voltage -60V, the current of the Ta target material is linearly reduced from 3.0A to 2.5A, the current of the MoS2 target material is linearly increased from 0.2A to 0.4A, the linear change time is 5min, and the sputtering time is 10min.

[0096] (5) A top layer is deposited on the surface of the intermediate layer obtained in step (4) by magnetron sputtering to obtain a transition layer; the process parameters are: argon flow rate 10 sccm, negative bias voltage -60V, the current of Ta target material is linearly reduced from 2.5A to 0.2A, the current of MoS2 target material is linearly increased from 0.4A to 0.8A, the current of Pb target material is linearly increased from 0A to 0.2A, the linear change time is 5min, and the sputtering time is 10min;

[0097] (6) A functional layer is deposited on the transition layer obtained in step (5) by magnetron sputtering to obtain a low-friction, high-wear-resistant solid lubricating film. The process parameters are: argon flow rate 15 sccm, substrate negative bias voltage -60V, Ta target current 0.2A, MoS2 target current 1.0A, Pb target current 0.2A, and time 200min.

[0098] Figure 1 This is a schematic diagram showing the positional relationship of each target material in Example 1.

[0099] from Figure 1 It can be seen that the two MoS2 targets are placed opposite each other, and the Ta and Pb targets are placed opposite each other. Since this solid lubricating film is based on molybdenum disulfide, which has the highest content, two molybdenum disulfide targets are used. At the same time, placing them opposite each other helps to improve the element doping uniformity of the sputtered film. Figure 1 The arrows near the target material indicate the direction of the magnetic field lines. In this embodiment 1, a closed-field non-equilibrium magnetic field is used. On the one hand, the sputtered atoms and particles are deposited on the substrate surface to form a thin film. On the other hand, the plasma bombards the substrate with a certain energy, which plays the role of ion beam-assisted deposition and greatly improves the quality of the film. The sample stage can revolve clockwise, and the sample holder can be controlled to rotate counterclockwise, which also greatly improves the uniformity of the coating.

[0100] Example 2

[0101] The other steps are the same as in Example 1, except that the substrate is changed to a single-crystal silicon wafer.

[0102] Figure 2 The surface morphology and elemental content of the low-friction, high-wear-resistant solid lubricating film prepared in Example 2 are shown.

[0103] from Figure 2 It can be seen that the surface of the prepared solid lubricating film is relatively dense and the particle size is uniform, with the particle size ranging from about 100 to 200 nm. The main elements on the surface are Mo, S, Ta and Pb, with the atomic content of Mo being 38.87%, S being 30.71%, Ta being 9.31%, and Pb being 21.10%.

[0104] Figure 3 The image shows the elemental distribution of the low-friction, high-wear-resistant solid lubricant film prepared in Example 2.

[0105] from Figure 3 It can be seen that the elements in the solid lubricating film are distributed relatively evenly, and no agglomeration phenomenon is observed.

[0106] Figure 4This is a TEM image of the low-friction, high-wear-resistant solid lubricating film prepared in Example 2.

[0107] from Figure 4 It can be seen that the solid lubricating film is mainly amorphous, which indicates that MoS2 mainly exists in the amorphous state. The interplanar spacing of some crystalline molybdenum disulfide is about 0.636 nm, and according to the PDF card, the molybdenum disulfide crystal plane is (002). There are crystals with an interplanar spacing of 0.238 nm, which is Ta (110) according to the PDF card. There are crystals with an interplanar spacing of 0.25 nm, which is Pb (101) according to the PDF card.

[0108] Figure 5 This is a microscopic cross-sectional view of the low-friction, high-wear-resistant solid lubricating film prepared in Example 2.

[0109] from Figure 5 It can be seen that the cross-section of the solid lubricating film has obvious structural layering, with the transition layer having a thickness of about 200 nm and the functional layer having a thickness of 1.28 μm.

[0110] Figure 6 The friction coefficient diagram shows the low-friction, high-wear-resistant solid lubricating film prepared in Example 2.

[0111] The friction coefficient test was conducted using a commercially available HVTRB friction testing machine, under a load of 5N, a friction radius of 6mm, and a rotation speed of 500rpm.

[0112] from Figure 6 It can be seen that the friction coefficient of the solid lubricating film does not exceed 0.04. After the initial friction start-up stage, the friction coefficient is basically stable at around 0.03, showing a trend of first decreasing and then increasing. After 500,000 revolutions, it still maintains a low friction coefficient.

[0113] Figure 7 The image shows the three-dimensional morphology of the low-friction, high-wear-resistant solid lubricating film prepared in Example 2 after 500,000 revolutions of friction in a vacuum environment.

[0114] from Figure 7 It can be seen that the wear track width is about 150μm and the wear track depth is less than 1μm, indicating that the solid lubricating film has not yet failed and has not worn down to the substrate.

[0115] Figure 8 The image shows the bonding strength test results of the low-friction, high-wear-resistant solid lubricant film prepared in Example 2. The bonding strength was measured using the scratch method. Specifically, the maximum indenter load was set to 50 N, the scratching speed to 5 mm / min, and the bonding strength was determined based on the scratch morphology.

[0116] from Figure 8It can be seen that the solid lubricating film only begins to peel off at 7.3N, and the film is completely peeled off at 22N, with a bonding strength as high as 22N.

[0117] Example 3

[0118] The other steps are the same as in Example 1, except that the argon flow rate during transition layer deposition is changed from 10 sccm to 16 sccm.

[0119] Figure 9 The surface morphology of the low-friction, high-wear-resistant solid lubricating film prepared in Example 3 is shown.

[0120] from Figure 9 It can be seen that the surface of the solid lubricating film exhibits typical morphological characteristics of a molybdenum disulfide film, with relatively uniform surface particles.

[0121] As can be seen from the above embodiments, the solid lubricating film provided by the present invention has excellent friction reduction and wear resistance properties, and has a high bonding strength with the substrate.

[0122] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A low-friction, high-wear-resistant solid lubricating film, comprising a substrate, a transition layer, and a functional layer arranged sequentially from bottom to top; The transition layer comprises, from bottom to top, a bottom layer, a middle layer, and an upper layer; The bottom layer is composed of Ta; the middle layer is composed of Ta and MoS2; the top layer is composed of Ta, Pb and MoS2. The functional layer is composed of Ta, Pb and MoS2; The thickness of the functional layer is 1.0~1.5μm; based on the total atomic percentage of Ta, Pb and Mo in the functional layer being 100%, the functional layer contains 5%~15% Ta, 15%~25% Pb and 65%~75% Mo. The method for preparing the low-friction, high-wear-resistant solid lubricating film includes the following steps: (1) A transition layer is deposited on the surface of the substrate using magnetron sputtering; (2) A functional layer is deposited on the transition layer by magnetron sputtering to obtain a low-friction, high-wear-resistant solid lubricating film; The operation of depositing a transition layer on the surface of the substrate using magnetron sputtering in step (1) includes the following steps: 1) A bottom layer is deposited on the surface of the substrate using magnetron sputtering; the process parameters of the magnetron sputtering method are: inert gas flow rate 10~20 sccm, negative bias voltage linearly decreasing from -250V to -60V, Ta target current linearly increasing from 1.5A to 3.0A, linear change time 5~10min, sputtering time 5~10min. 2) An intermediate layer is deposited on the surface of the substrate using magnetron sputtering. The process parameters for the magnetron sputtering method are as follows: inert gas flow rate 10~20 sccm, negative bias voltage -60V, current of Ta target material linearly decreasing from 3.0A to 2.5A, current of MoS2 target material linearly increasing from 0.2A to 0.4A, linear change time 5~10min, sputtering time 5~10min. 3) A transition layer is obtained by depositing an upper layer on the surface of the intermediate layer using magnetron sputtering. The process parameters of the magnetron sputtering method are as follows: inert gas flow rate 10~20 sccm, negative bias voltage -50V~-60V, current of Ta target linearly decreasing from 2.5A to 0.2A, current of MoS2 target linearly increasing from 0.4A to 0.8A, current of Pb target linearly increasing from 0A to 0.2A, the time for linear change is 5~10min, and the sputtering time is 5~10min. The process parameters for depositing the functional layer using magnetron sputtering in step (2) are as follows: inert gas flow rate 15 sccm, substrate negative bias voltage -60V, Ta target current 0.2A, MoS2 target current 1.0A, Pb target current 0.2A, and sputtering time 200 min.

2. The low-friction, high-wear-resistant solid lubricating film according to claim 1, characterized in that, The substrate is a monocrystalline silicon wafer or a stainless steel substrate.

3. The low-friction, high-wear-resistant solid lubricating film according to claim 1, characterized in that, The thickness of the bottom layer is 0.05~0.10μm; the thickness of the middle layer is 0.15~0.25μm; and the thickness of the top layer is 0.05~0.10μm.

4. A method for preparing the low-friction, high-wear-resistant solid lubricating film according to any one of claims 1 to 3, comprising the following steps: (1) A transition layer is deposited on the surface of the substrate using magnetron sputtering; (2) A functional layer is deposited on the transition layer by magnetron sputtering to obtain a low-friction, high-wear-resistant solid lubricating film; The operation of depositing a transition layer on the surface of the substrate using magnetron sputtering in step (1) includes the following steps: 1) A bottom layer is deposited on the surface of the substrate using magnetron sputtering; the process parameters of the magnetron sputtering method are: inert gas flow rate 10~20 sccm, negative bias voltage linearly decreasing from -250V to -60V, Ta target current linearly increasing from 1.5A to 3.0A, linear change time 5~10min, sputtering time 5~10min. 2) An intermediate layer is deposited on the surface of the substrate using magnetron sputtering. The process parameters for the magnetron sputtering method are as follows: inert gas flow rate 10~20 sccm, negative bias voltage -60V, current of Ta target material linearly decreasing from 3.0A to 2.5A, current of MoS2 target material linearly increasing from 0.2A to 0.4A, linear change time 5~10min, sputtering time 5~10min. 3) A transition layer is obtained by depositing an upper layer on the surface of the intermediate layer using magnetron sputtering. The process parameters of the magnetron sputtering method are as follows: inert gas flow rate 10~20 sccm, negative bias voltage -50V~-60V, current of Ta target linearly decreasing from 2.5A to 0.2A, current of MoS2 target linearly increasing from 0.4A to 0.8A, current of Pb target linearly increasing from 0A to 0.2A, the time for linear change is 5~10min, and the sputtering time is 5~10min. The process parameters for depositing the functional layer using magnetron sputtering in step (2) are as follows: inert gas flow rate 15 sccm, substrate negative bias voltage -60V, Ta target current 0.2A, MoS2 target current 1.0A, Pb target current 0.2A, and sputtering time 200 min.

5. The preparation method according to claim 4, characterized in that, The step (1) of the substrate also includes cleaning and etching the substrate in sequence before use.

6. The application of the low-friction, high-wear-resistant solid lubricating film according to any one of claims 1 to 3 or the low-friction, high-wear-resistant solid lubricating film prepared by the preparation method according to any one of claims 4 to 5 in a vacuum environment.

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