A multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film and its preparation and application

Abstract

This invention discloses a multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricant film, its preparation, and its application. The film, from bottom to top, comprises a W18Cr4V substrate, a Ti transition layer, and a WS2-Al2O3-Ag composite structure. The thickness of the Ti transition layer is 200 nm to 400 nm, and the thickness of the WS2-Al2O3-Ag composite structure is 1200 nm to 1800 nm. This invention solves the problem that existing solid lubricant coatings cannot simultaneously meet the requirements of long-life, stable service in a vacuum at high temperatures. The multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricant film, prepared through the synergistic preparation of WS2, Ag, and Al2O3, exhibits low friction and high wear resistance in a 700℃ vacuum environment: average friction coefficient <0.18, wear life >3×10⁻⁶. 4 Rotation, wear rate 2.010 ‑5 mm 3 / N ‑1 m ‑1 .

Description

Technical Field

[0001] This invention belongs to the field of lubricating film materials for harsh vacuum high-temperature environments, specifically relating to a multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film and its preparation and application. Background Technology

[0002] In high-end equipment such as aerospace, space probes, advanced nuclear reactors, and space reactors, key moving components (such as bearings, gears, and slide rails) often need to operate in high vacuum (10⁻⁶ ℃). -3 It can operate reliably for a long time in environments with temperatures below 80°C and high temperatures (300°C to 600°C or even higher). Under such conditions, traditional liquid lubricating oils or greases will completely fail due to evaporation and decomposition, and it is necessary to rely on solid lubricating films to achieve friction reduction and wear resistance.

[0003] Currently, all developed solid lubricating materials exhibit significant technical drawbacks when applied alone in the aforementioned high-temperature vacuum environments: Tungsten disulfide (WS2) films possess excellent layered structures and exhibit extremely low coefficients of friction in a vacuum. However, their high-temperature stability is poor; they are prone to oxidation in oxygen-containing or residual atmospheres exceeding 400°C, leading to a sharp decline in lubrication performance. Simultaneously, pure WS2 films have limited mechanical strength and insufficient wear resistance, making them unsuitable for long-life service requirements. Alumina (Al2O3) films possess good high-temperature chemical stability, high hardness, and excellent wear resistance. However, their inherent friction-reducing properties are poor, resulting in a relatively high coefficient of friction when used alone, and they easily cause excessive wear on the surfaces of friction pairs, making them unsuitable for scenarios with stringent requirements for low friction coefficients. Silver (Ag) films can form low-shear-strength lubricating films through surface diffusion at high temperatures, thereby improving high-temperature adaptability. However, silver is prone to agglomeration in a vacuum, and its interfacial bonding strength with the matrix and ceramic phase is weak, leading to premature peeling of the film during service.

[0004] Existing document 1 (publication number CN109338266A) discloses a wear-resistant self-lubricating coating and its preparation method. This method aims to improve the tribological properties of a substrate surface and enhance its wear resistance and friction reduction performance, applicable to high-strength steel, aluminum alloys, titanium alloys, and other alloys. The wear-resistant self-lubricating coating is prepared from alumina-based powder and molybdenum disulfide powder as raw materials, wherein the weight ratio of alumina-based powder to molybdenum disulfide powder is (70-90):(10-30). Using the above mixture as raw material, deionized water and PVA binder are added, and the mixture is then ball-milled. The resulting slurry is dried, kept warm to form a composite powder containing a molybdenum disulfide lubricating phase, crushed into powder, and sieved. Plasma spraying technology is used to spray the above mixed powder onto the surface of low-alloy ultra-strong steel to form a plasma-sprayed alumina-based wear-resistant coating containing a molybdenum disulfide lubricating phase. Reference 1 uses alumina and molybdenum disulfide to prepare the coating, relying solely on molybdenum disulfide for lubrication. It lacks high-temperature oxidation resistance and anti-agglomeration design, making it unsuitable for high-temperature vacuum conditions and failing to address the narrow temperature range and easy film peeling issues associated with single lubricant materials. Reference 2 (Korzekwa, J.; Bara, M.; Kaptacz, S. Al2O3 / WS2 Surface Layers Produced on the Basis of Alμminμm Alloys for Applications in Oil-Free Kinematic Systems. Materials 2021, 14, 7738.) A study (https: / / doi.org / 10.3390 / ma14247738) prepared an alumina composite coating (Al2O3 / WS2) doped with a single layer of 2H-phase tungsten disulfide. This coating was applied to an oil-free motion system using an electromagnetically controlled pneumatic actuator as the platform. A commercially available EN-AW-6063 aluminum alloy cylinder was used. A pure alumina coating and an Al2O3 / WS2 composite coating were prepared on the inner wall of the cylinder using a three-component electrolyte anodizing process. The cylinder was equipped with carbon-filled PTFE piston rings and polyurethane seals, and tests were conducted under dry friction conditions. SEM / EDS characterization revealed that a tungsten disulfide-containing lubricating slip film could form on the surface of the WS2-modified coating. The cylinder equipped with this composite coating operated stably for 180 hours, while the cylinder with the pure alumina coating experienced malfunctions after approximately 70 hours. However, Reference 2 only prepared an Al2O3 / WS2 binary coating, which is aimed at conventional oilless pneumatic dry friction scenarios. It did not conduct vacuum and high-temperature environment tests, and could not solve the defects of WS2 high-temperature oxidation and insufficient high-temperature lubrication, nor did it have the ability to serve in a wide temperature range.Reference 3 (CN118639198A) provides a nanocomposite / multilayer tungsten disulfide-based thin film and its preparation method, belonging to the field of solid lubricating film technology. The preparation method of the film includes the following steps: First, a pretreated substrate is obtained; then, using magnetron sputtering deposition technology, a WS2-Au composite layer is deposited by radio frequency sputtering with a pure WS2-Au target, and a Ti thin layer is deposited by DC sputtering with a Ti target. The WS2-Au composite layer and the Ti layer are periodically and alternately deposited to a predetermined thickness of the film to obtain a nanocomposite / multilayer WS2-Au / Ti thin film. The composition and structure of the film are optimized by selecting Au and Ti elements with good compatibility with WS2 crystals, and a dense nanocomposite / multilayer WS2-Au / Ti thin film with preferred orientation of the basal plane is designed and prepared, wherein the Au atomic percentage is preferably 0.1~10%. However, Reference 3 is a WS2-Au / Ti multilayer film, which only has Au and Ti optimized structure. The overall mechanical strength and wear resistance of the film are insufficient. At the same time, it lacks the high-temperature lubricating component Ag, making it difficult to maintain stable low friction performance in vacuum high-temperature environment. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-component composite WS2-Al2O3-Ag solid lubricating film, its preparation, and its application. This solves the problem that existing solid lubricating coatings cannot simultaneously meet the requirements of vacuum, high temperature, long service life, and stable operation. The multi-component composite WS2-Al2O3-Ag solid lubricating film, prepared through the synergistic effect of the three components, exhibits low friction and high wear resistance in a 700℃ vacuum environment: average friction coefficient <0.18, wear life >3×10⁻⁶. 4 Rotation, wear rate 2.010 -5 mm 3 / N -1 m -1 .

[0006] To achieve the above objectives, the present invention provides a multi-component composite WS2-Al2O3-Ag solid lubricating film, which comprises, from bottom to top, a W18Cr4V substrate, a Ti transition layer, and a WS2-Al2O3-Ag composite structure; wherein, the thickness of the Ti transition layer is 200nm~400nm; and the thickness of the WS2-Al2O3-Ag composite structure is 1200nm~1800nm.

[0007] Preferably, the atomic percentages of W, S, Al, O and Ag in the thin film are 14:24:16:41:5.

[0008] Preferably, the thickness of the Ti transition layer is 300 nm, and the thickness of the WS2-Al2O3-Ag composite structure is 1500 nm.

[0009] This invention provides a method for preparing a multi-component composite WS2-Al2O3-Ag solid lubricating film as described above. The method utilizes physical vapor deposition and employs a Ti target, a WS2-Al2O3 composite target, and an Ag target for deposition, wherein the WS2-Al2O3 composite target and the Ag target are simultaneously deposited on the Ti transition layer.

[0010] Preferably, the method specifically includes: (1) Install WS2-Al2O3 composite target, Ti target and Ag target, ultrasonically clean W18Cr4V substrate with anhydrous ethanol, blow dry, and use argon plasma to etch the natural oxide layer and impurity contamination layer on the surface. (2) On the etched W18Cr4V substrate, a Ti transition layer was deposited at 150°C, the argon flow rate was controlled at 60 sccm, the working pressure was 0.7 Pa, and the DC power supply of the Ti target was controlled at 1100 W. (3) On the Ti transition layer, deposit the WS2-Al2O3-Ag multi-element composite layer: the argon flow rate is controlled at 60 sccm, the working pressure is kept constant at 0.7 Pa, the DC power of sputtering Ag target is 35 W, the RF power of sputtering WS2-Al2O3 composite target is 1200 W, and both Ag target and WS2-Al2O3 composite target are sputtered at the same time.

[0011] Preferably, in step (1), the purity of the WS2-Al2O3 composite target, Ti target and Ag target is >99.99%; the bias voltage of the argon plasma is -400~-500V.

[0012] Preferably, in step (2), the deposition time of the Ti transition layer is 35~45 min and the substrate bias is adjusted to -150V.

[0013] Preferably, in step (3), the deposition time of the WS2-Al2O3-Ag multi-element composite layer is 140~160 min, and the substrate bias voltage is adjusted to -50V.

[0014] Preferably, in step (2), the method further includes evacuating the cavity to a pressure below 1.3 × 10⁻⁶ before the start of the thin film deposition process. -3 Pa.

[0015] This invention provides an application of the multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubrication film as described above in the field of vacuum high-temperature lubrication.

[0016] This invention discloses a multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film, its preparation, and its application. This invention solves the problem that existing solid lubricating coatings cannot simultaneously meet the requirements of long-life, stable service in vacuum high-temperature environments, and has the following advantages: 1. This invention overcomes the limitation of a single lubricating material being effective only in a narrow temperature range by the synergistic effect of three phases: WS2 (vacuum low friction), Ag (high temperature diffusion lubrication) and Al2O3 (high temperature stability enhancement). It can still maintain a low coefficient of friction (<0.2) in a vacuum high temperature environment of 700℃, filling the performance gap of the prior art under the cross-condition of "vacuum + high temperature".

[0017] 2. This invention uses Al2O3 as a hard reinforcing phase, which significantly improves the mechanical strength, hardness, and resistance to plastic deformation of the film. Simultaneously, the addition of Ag alleviates interfacial stress and reduces crack initiation, resulting in an extremely low wear rate of the composite film during vacuum high-temperature friction, thereby significantly extending the service life of moving parts. Furthermore, the ceramic properties of Al2O3 and the dense structure formed in the film effectively inhibit the oxidative decomposition of WS2 in a vacuum high-temperature environment. The addition of Al2O3 also improves the interfacial compatibility between the film and the metal substrate, reducing the risk of early spalling failure.

[0018] 3. This invention avoids excessive Ag aggregation by using a multi-element co-deposition process (such as adjusting the Ag content to an appropriate ratio, such as 5~15 at%) in physical vapor deposition. Simultaneously, the high-temperature diffusion layer of Ag can partially seal film defects, further enhancing the chemical stability of the film under vacuum and high-temperature conditions, thus avoiding the problem of rapid failure of traditional WS2 films due to oxidation.

[0019] 4. The pure WS2 film of this invention is prone to oxidation and failure at high temperatures; the pure Al2O3 film has an excessively high coefficient of friction; the pure Ag film is prone to agglomeration and peeling, and has poor lubrication at room temperature; ordinary WS2-Ag composite films lack a hard phase support, resulting in high wear. This invention solves these multiple defects at once through a three-phase composite design, achieving a comprehensive performance balance of "low friction, high wear resistance, oxidation resistance, and strong bonding." This composite film can be adapted to different working conditions (such as vacuum pressure, temperature gradient, and load speed) by adjusting the ratio of WS2, Al2O3, and Ag. It can be prepared by physical vapor deposition, is highly compatible with commonly used component materials and process lines in aerospace and nuclear industries, and is easy to promote and apply. Attached Figure Description

[0020] Figure 1 The results are EDS composition test results of the multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film in Example 1 of this invention.

[0021] Figure 2 The XRD patterns are those of the WS2 thin film and the multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film in Examples 1-2 of this invention.

[0022] Figure 3The images show surface SEM images of WS2 and WS2-Al2O3-Ag in Examples 1-2 of this invention.

[0023] Figure 4 The friction coefficient curves of the uncoated substrate sample, the WS2 film coated sample, and the multi-component composite WS2-Al2O3-Ag vacuum high temperature film coated sample in the present invention 1-2 are shown at a vacuum high temperature of 700°C.

[0024] Figure 5 The friction coefficient curves of the uncoated substrate samples, the samples coated with WS2 thin film and the samples coated with WS2-Ag composite film in Examples 2-3 of the present invention are shown at a vacuum high temperature of 700°C.

[0025] Figure 6 The friction coefficient curves of the uncoated substrate sample, the sample coated with WS2 film, and the sample coated with WS2-Al2O3-Ti composite film in Examples 2 and 4 of the present invention are shown at a vacuum high temperature of 700°C. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Information on physical vapor deposition equipment and targets involved in the following embodiments The radio frequency magnetron sputtering system was manufactured by Shenyang Scientific Instruments Co., Ltd., Chinese Academy of Sciences. The magnetron sputtering equipment mainly consists of a deposition chamber, a substrate, two DC power supplies, one radio frequency power supply, one bias power supply, and a vacuum pumping device. The sputtering power supply is connected to the target material, and the bias power supply is connected to the substrate. The equipment includes three independently controllable magnetron sputtering sources, each equipped with a WS2-Al2O3 composite target, a Ti target and Ag target, a WS2 target and Ti target, a WS2 target and Ti target, and a WS2-Al2O3 composite target and Ti target, respectively.

[0028] The purity of the WS2-Al2O3 composite target was 99.99%, the purity of the Ti target was 99.995%, the purity of the Ag target was 99.995%, and the purity of the WS2 target was 99.99%. All targets were rectangular, with dimensions of 450 mm in length and 80 mm in width, and the distance between all targets and the substrate was 12 cm.

[0029] Example 1 A method for preparing a multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricant film employs physical vapor deposition. This method includes: (1) Substrate Cleaning: WS2-Al2O3 composite targets, Ti targets, and Ag targets are respectively installed on the three independently controllable magnetron sputtering sources of the magnetron sputtering equipment. The W18Cr4V substrate is ultrasonically cleaned in acetone for 10 min, then cleaned in anhydrous ethanol for 10 min, dried with an air gun, and placed in the deposition chamber. Before depositing the thin film, the W18Cr4V substrate is etched with argon plasma at a bias voltage of -500V for 10 min to remove the natural oxide layer and impurity contamination layer on the substrate surface. Before the thin film deposition process begins, the chamber is evacuated to a pressure below 1.3 × 10⁻⁶. -3 Pa.

[0030] (2) Deposit a Ti transition layer on a W18Cr4V substrate: the substrate bias voltage is adjusted to -150V, the argon flow rate is controlled at 60sccm, the working pressure is 0.7Pa, the deposition temperature is 150℃, the DC power supply of the Ti target is controlled at 1100W, the deposition time is 40min, and a 300nm thick Ti transition layer is deposited on the W18Cr4V substrate.

[0031] (3) Depositing a WS2-Al2O3-Ag multi-component composite layer on the Ti transition layer: the argon flow rate is controlled at 60 sccm, the working pressure is kept constant at 0.7 Pa, the substrate bias voltage is adjusted to -50 V, the DC power of the sputtering Ag target is 35 W, the RF power of the sputtering WS2-Al2O3 composite target is 1200 W, the two targets are sputtered simultaneously, the deposition time is 180 min, a WS2-Al2O3-Ag layer with a thickness of 1500 nm is deposited on the Ti transition layer, and a multi-component composite WS2-Al2O3-Ag vacuum high temperature solid lubricating film with a thickness of 1.8 μm is obtained.

[0032] like Figure 1 The image shows the EDS composition test results of the multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricant film in Example 1 of this invention. Figure 1 It can be seen that in the multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film in Example 1, the atomic percentage is W∶S∶Al∶O∶Ag=14∶24∶16∶41∶5.

[0033] Example 2 A WS2 lubricating film for use in a vacuum high-temperature environment is basically the same as that in Example 1, except that: In step (1), a WS2 target and a Ti target are respectively installed on the independent controllable magnetron sputtering source of the magnetron sputtering equipment.

[0034] In step (3), a pure WS2 thin film was deposited on the Ti transition layer: the argon flow rate was 60 sccm, the plasma working pressure was 0.7 Pa, the deposition temperature was 150 °C, the WS2 target power was 1200 W, the deposition time was 180 min, and the thickness of the pure WS2 thin film was approximately 2100 nm. Finally, a WS2 lubricating material with a thickness of approximately 2.4 μm was obtained on the W18Cr4V substrate.

[0035] like Figure 2 The XRD patterns of the WS2 thin film and the multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film in Examples 1-2 of this invention are shown below. Figure 2 It can be seen that the WS2 film in Example 2 exhibits a close-packed hexagonal structure with a clear (100) preferred orientation, while the WS2-Al2O3-Ag composite film in Example 1 shows the crystalline phases of Al2O3, WS2, and Ag, with a significantly reduced grain size and no obvious preferred orientation. After combining Al2O3 and doping with Ag, the preferential growth of WS2 (110) and (100) orientations is suppressed. Co-sputtering ceramics and metals can refine the grain size of the WS2 film, prevent crystal growth, and increase the hardness of the multi-component composite WS2-Al2O3-Ag solid lubricant film.

[0036] like Figure 3 As shown, in embodiments 1-2 of the present invention, WS 2、 SEM images of WS2-Al2O3-Ag and its surface after service at 700℃. Figure 3 As can be seen, the WS2 film surface in Example 2 has a porous worm-like or dendritic structure with numerous voids. The multi-component composite WS2-Al2O3-Ag vacuum high-temperature film exhibits a highly dense structure, with a surface dominated by uniformly distributed fine particles interspersed with larger Ag particles, and virtually no voids between the fine particles. Ag doping enables the uniform distribution of silver grains within the composite film. The addition of Al2O3 refines the film grain size, inhibits crystal growth, and results in smaller inter-grain gaps, leading to tighter stacking during film deposition and a denser structure.

[0037] This invention uses Si3N4 as a pair and employs a GHT-1000E high-temperature vacuum tribology and wear testing machine to evaluate the tribology and wear performance of the thin film material under vacuum and high temperature conditions of 700℃, a load of 200g, a rotation speed of 500r / min, and a rotation radius of 4mm.

[0038] like Figure 4The figures show the friction coefficient curves of the uncoated substrate sample, the WS2-coated film, and the multi-component composite WS2-Al2O3-Ag vacuum high-temperature film samples from embodiments 1 and 2 of this invention at a vacuum high temperature of 700°C. The uncoated substrate sample is a W18 steel block, the WS2-coated film is the film obtained in Example 2, and the multi-component composite WS2-Al2O3-Ag vacuum high-temperature film is the film obtained in Example 1. Figure 4 It can be seen that the friction coefficient of the uncoated W18Cr4V sample rapidly increased to >0.8 after running-in and continued to increase; the friction coefficient of the WS2 film under vacuum at 700℃ was about 0.2 within the first 4000 revolutions, and then rapidly increased to >0.4, with a wear life of <4000 revolutions; the friction coefficient of the multi-component composite WS2-Al2O3-Ag film after running-in was about 0.1~0.18, and <0.18 within 30000 revolutions under vacuum at 700℃, with a wear life greater than 3×10⁻³. 4 Rotational speed (60 min), wear rate 2.010. -5 mm 3 / N -1 m -1 .

[0039] Example 3 A WS2-Ag composite solid lubricating film for vacuum high-temperature environments is basically the same as that in Example 1, except that: In step (1), WS2 target, Ti target and Ag target are respectively installed on the independent controllable magnetron sputtering source of the magnetron sputtering equipment.

[0040] In step (3), a WS2-Ag thin film is deposited on the Ti transition layer: the argon flow rate is controlled at 60 sccm, the working pressure is kept constant at 0.7 Pa, the substrate bias voltage is adjusted to -50 V, the DC power of the sputtering Ag target is 35 W, the RF power of the sputtering WS2 target is 1200 W, the two targets are sputtered simultaneously, the deposition time is 180 min, and a WS2-Ag layer with a thickness of 1900 nm is deposited on the Ti transition layer.

[0041] This invention uses Si3N4 as a pair and employs a GHT-1000E high-temperature vacuum tribology and wear testing machine to evaluate the tribology and wear performance of the thin film material under vacuum and high temperature conditions of 700℃, a load of 200g, a rotation speed of 500r / min, and a rotation radius of 4mm.

[0042] like Figure 5 As shown, the friction coefficient curves of the uncoated substrate sample, the WS2-coated film sample, and the WS2-Ag composite film sample in Examples 2-3 of this invention are displayed at a vacuum high temperature of 700°C. The uncoated substrate sample is a W18 steel block, the WS2-coated film is the film obtained in Example 2, and the WS2-Ag multi-element composite film is the film obtained in Example 3. Figure 5 It can be seen that the friction coefficient of the uncoated W18Cr4V sample rapidly increased to >0.8 after running-in and continued to increase; the friction coefficient of the WS2 film under vacuum at 700℃ was about 0.2 within the first 4000 revolutions, and then rapidly increased to >0.4, with a wear life of <4000 revolutions; the friction coefficient of the WS2-Ag composite film after running-in was about 0.13~0.23, and <0.23 within 30000 revolutions under vacuum at 700℃ (about 27.8% higher than that of the multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricant), with a wear life greater than 3×10 4 Rotational speed (60 min), wear rate 2.210. -5 mm 3 / N - 1m -1 This means that its coefficient of friction is relatively large under vacuum and high temperature conditions.

[0043] The above results indicate that introducing an Ag high-temperature diffused lubricating phase into the WS2 film can reduce its vacuum high-temperature friction coefficient and increase its wear life. This confirms that the addition of Ag can alleviate interfacial stress, reduce crack initiation, and enable the composite film to exhibit a lower wear rate during vacuum high-temperature friction, thereby significantly extending the service life of moving parts. However, compared to... Figure 4 The high-temperature friction coefficient curve of the multi-component composite WS2-Al2O3-Ag film in Example 1 shows that the friction coefficient of the composite film with Ag particles alone is still unstable and the friction coefficient value is still relatively large. It is necessary to continue to add a high-temperature hard reinforcing phase to further improve the high-temperature stability of the film.

[0044] Example 4 A WS2-Al2O3-Ti composite solid lubricating film for vacuum high-temperature environments is basically the same as that in Example 1, except that: In step (1), a WS2-Al2O3 composite target and a Ti target are respectively installed on the independent controllable magnetron sputtering source of the magnetron sputtering equipment.

[0045] In step (3), a WS2-Al2O3-Ti thin film is deposited on the Ti transition layer: the argon flow rate is controlled at 60 sccm, the working pressure is kept constant at 0.7 Pa, the substrate bias voltage is adjusted to -50V, the DC power of the sputtering Ti target is 80W, the RF power of the sputtering WS2-Al2O3 target is 1200W, the two targets are sputtered simultaneously, the deposition time is 200 min, and a WS2-Al2O3-Ti layer with a thickness of 1500 nm is deposited on the Ti transition layer.

[0046] This invention uses Si3N4 as a pair and employs a GHT-1000E high-temperature vacuum tribology and wear testing machine to evaluate the tribology and wear performance of the thin film material under vacuum and high temperature conditions of 700℃, a load of 200g, a rotation speed of 500r / min, and a rotation radius of 4mm.

[0047] like Figure 6 The figures show the friction coefficient curves of the uncoated substrate sample, the WS2-coated film, and the WS2-Al2O3-Ti composite film samples in Examples 2 and 4 of this invention at a vacuum high temperature of 700°C. The uncoated substrate sample was a W18 steel block, the WS2-coated film was the film obtained in Example 2, and the WS2-Al2O3-Ti multi-element composite film was the film obtained in Example 4. Figure 6 It can be seen that the friction coefficient of the uncoated W18Cr4V sample rapidly increased to >0.8 after running-in and continued to increase; the friction coefficient of the WS2 film under vacuum at 700℃ was about 0.2 within the first 4000 revolutions, and then rapidly increased to >0.4, with a wear life of <4000 revolutions; the friction coefficient of the WS2-Al2O3-Ti composite film after running-in was about 0.11~0.27, and <0.27 within 30000 revolutions under vacuum at 700℃ (about 50% higher than that of the multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricant), with a wear life of less than 3×10⁻³. 4 The friction coefficient is relatively high and the wear life is relatively short under vacuum and high temperature conditions (60 min).

[0048] The above results indicate that introducing Al2O3 and Ti hard reinforcing phases into WS2 films can reduce the high-temperature vacuum friction coefficient of WS2 to a certain extent and increase its wear life. This confirms that the addition of the hard phase improves the film density, enhances the interfacial compatibility between the film and the metal substrate, and can reduce the high-temperature vacuum friction coefficient of the film. However, compared with... Figure 4 The high-temperature friction coefficient curve of the multi-component composite WS2-Al2O3-Ag film in Example 1 shows that the friction coefficient of the composite film with the introduction of a hard reinforcing phase alone is still relatively large and the friction coefficient fluctuates greatly. It is necessary to add a high-temperature lubricating phase to further reduce the high-temperature friction coefficient of the film and improve its high-temperature lubrication characteristics.

[0049] In summary, the multi-component composite WS2-Al2O3-Ag solid lubricating film prepared in Example 1 of this invention has a thickness of 1.8 μm. This film possesses a multi-component structure including high-temperature lubricating phase Ag particle doping, high-temperature hard reinforcing phase Al2O3 ceramic composite, polycrystalline reinforcement, and multi-component composite. The sample exhibits excellent high-temperature vacuum lubrication performance: <0.18 within 30,000 revolutions at 700℃ in a vacuum, and a wear life greater than 3 × 10⁻⁶. 4 Rotational speed (60 min), wear rate 2.010. -5 mm3 / N -1 m -1 .

[0050] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film, characterized in that, The film comprises, from bottom to top, a W18Cr4V substrate, a Ti transition layer, and a WS2-Al2O3-Ag composite structure; The thickness of the Ti transition layer is 200nm~400nm; The thickness of the WS2-Al2O3-Ag composite structure is 1200nm~1800nm.

2. The multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film according to claim 1, characterized in that, The atomic percentages of W, S, Al, O, and Ag in the thin film are 14:24:16:41:

5.

3. The multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film according to claim 1, characterized in that, The thickness of the Ti transition layer is 300 nm, and the thickness of the WS2-Al2O3-Ag composite structure is 1500 nm.

4. A method for preparing a multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film as described in any one of claims 1 to 3, characterized in that, This method utilizes physical vapor deposition, employing a Ti target, a WS2-Al2O3 composite target, and an Ag target for deposition, wherein the WS2-Al2O3 composite target and the Ag target are deposited simultaneously on the Ti transition layer.

5. The method according to claim 4, characterized in that, This method specifically includes: (1) Install WS2-Al2O3 composite target, Ti target and Ag target, ultrasonically clean W18Cr4V substrate with anhydrous ethanol, blow dry, and use argon plasma to etch the natural oxide layer and impurity contamination layer on the surface. (2) On the etched W18Cr4V substrate, a Ti transition layer was deposited at 150°C, the argon flow rate was controlled at 60 sccm, the working pressure was 0.7 Pa, and the DC power supply of the Ti target was controlled at 1100 W. (3) On the Ti transition layer, deposit the WS2-Al2O3-Ag multi-element composite layer: the argon flow rate is controlled at 60 sccm, the working pressure is kept constant at 0.7 Pa, the DC power of sputtering Ag target is 35 W, the RF power of sputtering WS2-Al2O3 composite target is 1200 W, and both Ag target and WS2-Al2O3 composite target are sputtered at the same time.

6. The method according to claim 5, characterized in that, In step (1), the purity of the WS2-Al2O3 composite target, Ti target and Ag target is >99.99%; the bias voltage of the argon plasma is -400~-500V.

7. The method according to claim 5, characterized in that, In step (2), the deposition time of the Ti transition layer is 35~45 min and the substrate bias is adjusted to -150V.

8. The method according to claim 5, characterized in that, In step (3), the deposition time of the WS2-Al2O3-Ag multi-element composite layer is 140~160 min, and the substrate bias voltage is adjusted to -50V.

9. The method according to claim 5, characterized in that, In step (2), the method further includes evacuating the cavity to a pressure below 1.3 × 10⁻⁶ before the start of the thin film deposition process. -3 Pa.

10. The application of the multi-component composite WS2-Al2O3-Ag vacuum high-temperature solid lubricating film as described in any one of claims 1 to 3 in the field of vacuum high-temperature lubrication.

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