A modified disulfide-based composite film, preparation method and application thereof

Abstract

This invention belongs to the field of lubricating materials technology, specifically relating to a modified disulfide-based composite film, its preparation method, and its application. The modified disulfide-based composite film of this invention comprises a matrix and a first metal oxide and a second metal oxide dispersed in the matrix; the first metal oxide includes one or more of WO3, TiO2, CaO, MoO3, Ta2O5, In2O3, Nb2O5, ZrO2, Cr2O3, and HaO2; the metal element in the second metal oxide is the same as that in the matrix. Introducing the first metal oxide into the matrix effectively refines the disulfide crystal particles and passivates active sites, thereby affecting its sensitivity to humid and hot conditions; through humid and hot storage treatment, the second metal oxide particles can be generated in situ, prompting them to transform the shear sliding of the WS2 film into a "rolling-sliding" cooperative mode during friction, reducing the coefficient of friction and improving its tribological properties.

Description

Technical Field

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

[0002] Transition metal dichalcogenides (such as WS2 and MoS2) are widely used as key solid lubricants for mechanical moving parts of spacecraft due to their layered crystal structure, low shear strength, excellent solid lubrication properties, and superior thermal stability in vacuum or inert environments. However, in real-world engineering applications, the surface coatings of spacecraft components inevitably undergo a period of ground processing, assembly, transportation, and storage. These stages are typically conducted under atmospheric pressure and humid conditions before the equipment enters on-orbit service or vacuum testing. Therefore, the sequence of operating conditions experienced by the thin film—first exposed to the atmosphere or humid environment, then operating in a vacuum—is a crucial factor that must be considered in its final tribological performance. Research on this sequence should focus not only on the in-situ stability under service environments (such as vacuum) but also on the changes in the tribological properties of the thin film after ground treatment or short-term storage before entering vacuum service.

[0003] Existing technologies address the effects of humid environments on disulfide films primarily employ two strategies: one aims to suppress or isolate environmental oxidation (e.g., through densification, multilayer structure design, or surface encapsulation) to preserve the original structure and composition of the coating; the other utilizes high doping levels to prepare composite films to enhance resistance to environmental corrosion. However, while these strategies reduce the impact of humid environments on disulfide films, they may weaken the intrinsic low-shear properties of the film, thereby affecting its tribological properties.

[0004] Therefore, developing a transition metal dichalcogenide thin film that can adapt to humidity environment, so that the film has both low friction coefficient and high stability, is of great significance for promoting its application in the field of precision moving parts of aerospace and high-end equipment. Summary of the Invention

[0005] In view of this, the present invention provides a modified disulfide-based composite film, its preparation method and application. The modified disulfide-based composite film provided by the present invention exhibits a stable and low coefficient of friction after being stored in humid air.

[0006] To address the aforementioned technical problems, the present invention provides a modified disulfide-based composite film, comprising a matrix and a first metal oxide and a second metal oxide dispersed in the matrix; The first metal oxide includes one or more of WO3, TiO2, CaO, MoO3, Ta2O5, In2O3, Nb2O5, ZrO2, Cr2O3, and HaO2; The metal element in the second metal oxide is the same as the metal element in the matrix.

[0007] Preferably, the atomic percentage of the metal element in the first metal oxide in the modified disulfide-based composite film is 1-5%.

[0008] Preferably, the second metal oxide is spherical at the friction interface, and the diameter of the sphere is 3~50nm.

[0009] Preferably, the substrate comprises a WS2 film or a MoS2 film.

[0010] Preferably, the thickness of the modified disulfide-based composite film is 0.5~3μm.

[0011] This invention also provides a method for preparing the modified disulfide-based composite film described in the above technical solution, comprising the following steps: A disulfide-based composite film is obtained by simultaneously sputtering a disulfide target and a metal oxide target on the substrate surface; the metal oxide target includes one or more of WO3 target, TiO2 target, CaO target, MoO3 target, Ta2O5 target, In2O3 target, Nb2O5 target, ZrO2 target, Cr2O3 target and HaO2 target. The disulfide-based composite film was modified by placing it in a humid and hot environment to obtain the modified disulfide-based composite film.

[0012] Preferably, the disulfide target includes a tungsten disulfide target or a molybdenum disulfide target; The sputtering includes radio frequency magnetron sputtering; the conditions for radio frequency magnetron sputtering include: argon as the working gas, argon flow rate of 20~90 sccm, working gas pressure of 1~10 Pa, substrate bias of -60~-10 V, substrate rotation speed of 1~6 r / min, substrate temperature of 50~600℃, vertical distance between the target and the substrate of 50~100 mm, sputtering power of disulfide target of 100~300 W, sputtering power of metal oxide of 10~200 W, and sputtering time of 20~40 min.

[0013] Preferably, the process before sputtering further includes: sequentially ultrasonically cleaning and drying the substrate, then fixing it on a sample holder for argon ion etching cleaning; The working gas pressure for the argon ion etching cleaning is 5~9 Pa, the bias voltage is -800~-400 V, and the time is 14~16 min.

[0014] Preferably, the temperature of the humid and hot environment is 5~50℃, and the relative humidity is 10~100%RH; the modification time is 1~10000h; The substrate includes 9Cr18 steel, bearing steel, or carbon steel.

[0015] The present invention also provides the application of the modified disulfide-based composite film described in the above technical solution or the modified disulfide-based composite film prepared by the preparation method described in the above technical solution as a solid lubricating material.

[0016] This invention provides a modified disulfide-based composite thin film, its preparation method, and its application. The film includes a matrix and a first metal oxide and a second metal oxide dispersed in the matrix. The first metal oxide includes one or more of WO3, TiO2, CaO, MoO3, Ta2O5, In2O3, Nb2O5, ZrO2, Cr2O3, and HaO2. The metal element in the second metal oxide is the same as that in the matrix. The introduction of the first metal oxide into the disulfide thin film inhibits, to some extent, the long-range layered ordered growth of disulfides during sputtering deposition, reducing the size of the WS2 crystals in the film, decreasing the film's crystallinity, and passivating the active sites in the film. The synergistic regulation of structure and chemical composition brought about by the introduction of the first metal oxide can achieve synergistic optimization of the film's tribological stability and resistance to damp heat, thereby ensuring that the composite film maintains a low coefficient of friction and excellent tribological stability after modification by humid air storage. This invention enables the in-situ generation of second metal oxide (e.g., tungsten oxide) particles in the film through wet heat storage modification. The second metal oxide is spherical at the friction interface, which promotes the transformation of the shear sliding of the WS2 film into a "rolling-sliding" cooperative mode during the friction process, thereby reducing the friction coefficient of the modified disulfide-based composite film and improving its tribological properties. Attached Figure Description

[0017] Figure 1 XRD patterns of the WS2 thin film prepared in Comparative Example 1 before and after humid heat storage; Figure 2 XPS spectra of the WS2 thin film prepared in Comparative Example 1 before and after humid heat storage; Figure 3 Friction curves of the WS2 film prepared for Comparative Example 1 before and after humid heat storage; Figure 4 Transmission electron microscopy image of the triboelectric interface of the WS2 thin film prepared for Comparative Example 1; Figure 5 Transmission electron microscopy image of the tribological interface of the modified WS2 film prepared for Comparative Example 1; Figure 6The XRD patterns of the WS2-WO3 composite film prepared in Example 1 before and after wet heat modification are shown below. Figure 7 The friction curves of the WS2-WO3 composite film prepared in Example 1 before and after wet heat modification are shown. Figure 8 The XRD patterns of the WS2-TiO2 composite film prepared in Example 2 before and after wet heat modification are shown below. Figure 9 XPS spectra of the WS2-TiO2 composite film prepared in Example 2 before and after wet heat modification; Figure 10 The friction curves of the WS2-TiO2 composite film prepared in Example 2 before and after wet heat modification are shown. Figure 11 The friction interface of the modified WS2-TiO2 composite film prepared in Example 2; Figure 12 The XRD patterns of the WS2-CaO composite film prepared in Example 3 before and after wet heat modification are shown below. Figure 13 The friction curves of the WS2-CaO composite film prepared in Example 3 before and after wet heat modification are shown. Figure 14 The friction curves of the WS2-MoO3 composite film prepared in Example 4 before and after wet heat modification are shown. Figure 15 The diagram shows a comparison of the friction mechanisms of WS2 thin film and modified disulfide-based composite film. The left side shows the friction mechanism of WS2 thin film, and the right side shows the friction mechanism of modified disulfide-based composite film. Detailed Implementation

[0018] The present invention provides a modified disulfide-based composite film, comprising a matrix and a first metal oxide and a second metal oxide dispersed in the matrix.

[0019] In this invention, the substrate includes a WS2 thin film or a MoS2 thin film; the first metal oxide includes one or more of WO3, TiO2, CaO, MoO3, Ta2O5, In2O3, Nb2O5, ZrO2, Cr2O3 and HaO2, and may specifically be WO3, TiO2, CaO, MoO3, Nb2O5, ZrO2, Cr2O3 or HaO2.

[0020] In this invention, the atomic percentage of the metal element in the first metal oxide in the modified disulfide-based composite film can be 1-5%, specifically 1%, 1.5%, 2%, 3%, 4%, or 4.5%. In this invention, the atomic percentage of oxygen in the modified disulfide-based composite film can be 10-70%, specifically 15%, 20%, 27%, 39%, 42%, 58%, or 60%.

[0021] In this invention, the second metal oxide is spherical at the friction interface, and the diameter of the sphere can be 3~50 nm, specifically 4.4 nm, 15 nm, 27.3 nm, 33.6 nm or 40 nm. The spherical second metal oxide can change the friction mode during the friction process to form a sliding-rolling mixed friction, thereby reducing the coefficient of friction. Figure 15 The diagram shows a comparison of the friction mechanisms of WS2 thin film and modified disulfide-based composite film. The left side shows the friction mechanism of WS2 thin film, and the right side shows the friction mechanism of modified disulfide-based composite film.

[0022] In this invention, the thickness of the modified disulfide-based composite film can be 0.5~3μm, specifically 1.3μm, 1.8μm, 2.0μm or 2.3μm.

[0023] This invention also provides a method for preparing the modified disulfide-based composite film described in the above technical solution, comprising the following steps: A disulfide-based composite film is obtained by simultaneously sputtering a disulfide target and a metal oxide target on the substrate surface; the metal oxide target includes one or more of WO3 target, TiO2 target, CaO target, MoO3 target, Ta2O5 target, In2O3 target, Nb2O5 target, ZrO2 target, Cr2O3 target and HaO2 target. The disulfide-based composite film was modified by placing it in a humid and hot environment to obtain the modified disulfide-based composite film.

[0024] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products.

[0025] This invention involves simultaneously sputtering a disulfide target and a metal oxide target onto a substrate surface to obtain a disulfide-based composite thin film. In this invention, the disulfide target may include a tungsten disulfide target or a molybdenum disulfide target; the metal oxide target includes one or more of the following: WO3 target, TiO2 target, CaO target, MoO3 target, Ta2O5 target, In2O3 target, Nb2O5 target, ZrO2 target, Cr2O3 target, and HaO2 target, specifically WO3 target, TiO2 target, CaO target, MoO3 target, Nb2O5 target, ZrO2 target, Cr2O3 target, or HaO2 target; the purity of the disulfide target and the metal oxide target can be above 99%, specifically 99.5%, 99.9%, and 99.99%, respectively.

[0026] In this invention, the substrate may include 9Cr18 steel, bearing steel or carbon steel.

[0027] In this invention, the pre-sputtering process may further include: sequentially ultrasonically cleaning and drying the substrate, followed by fixing it on a sample holder for argon ion etching cleaning. In this invention, the ultrasonic cleaning may include sequentially performing petroleum ether ultrasonic cleaning, anhydrous ethanol ultrasonic cleaning, and acetone ultrasonic cleaning; the durations of the petroleum ether ultrasonic cleaning, anhydrous ethanol ultrasonic cleaning, and acetone ultrasonic cleaning may be 14-16 minutes, or 15 minutes respectively. In this invention, the drying may be performed using high-purity nitrogen gas, wherein the purity of the high-purity nitrogen gas may be above 99%.

[0028] In this invention, the working gas pressure for argon ion etching and cleaning can be 5~9 Pa, specifically 7~8 Pa; the bias voltage for argon ion etching and cleaning can be -800~-400V, or -550~-450V, specifically -500V; the argon ion etching and cleaning time can be 14~16 min, specifically 15 min. Before filling the vacuum chamber with argon gas to adjust the pressure, the background vacuum level of the vacuum chamber needs to be evacuated to 1.0 × 10⁻⁶. -3 Below Pa.

[0029] In this invention, the sputtering can include radio frequency magnetron sputtering, specifically radio frequency co-sputtering; the conditions for radio frequency co-sputtering can include: argon as the working gas, argon flow rate 20~90 sccm, working gas pressure 1~10 Pa, substrate bias -60~-10 V, substrate rotation speed 1~6 r / min, substrate temperature 50~600℃, vertical distance between the target and the substrate 50~100 mm, sputtering power of disulfide target 100~300 W, sputtering power of metal oxide 10~200 W, and sputtering time 20~40 min; or it can be: argon as the working gas, argon flow rate 25~35 sccm, working gas pressure 3~5 Pa, substrate bias -50~-30 V, sample holder rotation... The sputtering speed is 2-4 r / min, the substrate temperature is 100-500℃, the vertical distance between the target and the substrate is 60-90 mm, the sputtering power of the disulfide target is 180-220 W, the sputtering power of the metal oxide target is 20-200 W, and the sputtering time is 20-40 min. Alternatively, the working gas can be argon, with a flow rate of 30 sccm and a working gas pressure of 3-5 Pa. The substrate bias voltage is -40 V, the sample holder rotation speed is 3 r / min, the substrate temperature is 70-300℃, the vertical distance between the target and the substrate is 70-80 mm, the sputtering power of the disulfide target is 200 W, the sputtering power of the metal oxide target is 20-150 W (specifically 30 W, 50 W, or 100 W), and the sputtering time is 30 min. This invention ensures uniform film thickness on the substrate surface by rotating the sample holder during sputtering.

[0030] In this invention, the process after sputtering may further include: maintaining the vacuum level of the chamber and cooling it to room temperature, wherein the room temperature may be 20~35°C or 25~30°C.

[0031] In this invention, the disulfide-based composite film has a distinct porous columnar structure and a surface exhibiting a "worm-like" morphological feature.

[0032] After obtaining the disulfide-based composite film, the present invention modifies the disulfide-based composite film by placing it in a humid and hot environment to obtain the modified disulfide-based composite film. In the present invention, the temperature of the humid and hot environment can be 5~50℃, specifically 10℃, 20℃, 30℃, or 40℃; the relative humidity of the humid and hot environment can be 10~100%RH, specifically 20%RH, 30%RH, 40%RH, 50%RH, 60%RH, 80%RH, or 90%RH; the modification time can be 1~10000h, specifically 10h, 50h, 100h, 120h, 200h, 500h, 1000h, or 5000h. The content of the second metal oxide in the modified disulfide-based composite film is determined by the humid and hot environment and the modification time.

[0033] This invention places a disulfide-based composite film in a humid and hot environment, where water vapor and oxygen diffuse inward along the micropores of the film, inducing controlled oxidation and significantly increasing the content of the internal oxide phase. After storage, the film undergoes interface reconstruction during friction (the second metal oxide exhibits a spherical structure, forming a sliding-rolling mixed friction), resulting in a novel shear interface with low frictional properties.

[0034] In this invention, the modification may further include: drying the modified product in a dry and clean environment to obtain the modified disulfide-based composite film.

[0035] This invention also provides the application of the modified disulfide-based composite film described in the above technical solution or the modified disulfide-based composite film prepared by the preparation method described in the above technical solution as a solid lubricating material; the solid lubricating material can be used to prepare moving parts of spacecraft machinery; the spacecraft machinery prepared can be spacecraft machinery assembled, stored and transported on the ground.

[0036] 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.

[0037] Example 1 9Cr18 steel was selected as the substrate material and ultrasonically cleaned sequentially in petroleum ether, anhydrous ethanol, and acetone for 15 minutes each. The cleaned substrate was then dried with 99.9% pure nitrogen gas and fixed on a sample holder within a vacuum chamber. The substrate temperature was adjusted to 100℃, and the vertical distance between the substrate and the sputtering target was 100 mm. The chamber was then evacuated until the background vacuum reached 1.0 × 10⁻⁶ mm. -3 At Pa, an appropriate amount of argon gas is introduced into the chamber and the working pressure is maintained at 8.0 Pa. A bias voltage of -500V is applied to perform Ar ion etching and cleaning on the substrate for 15 minutes.

[0038] Argon was used as the working gas, and the argon flow rate was adjusted to 30 sccm. The main pumping valve was adjusted to control the vacuum rate, maintaining the pressure in the vacuum chamber at 3.0 Pa. The substrate bias was set to -30 V, and the sample holder was started to rotate at a constant speed of 3.0 r / min. Radio frequency co-sputtering was used to deposit WS2 targets with a purity of 99.9% and WO3 targets with a purity of 99.99%, respectively. The sputtering power of the WS2 target was 200 W, and the sputtering power of the WO3 target was 30 W. After continuous sputtering for 30 min, the substrate was cooled to room temperature (25 °C) to form a disulfide-based composite film on the substrate surface, denoted as WS2-WO3 composite film. The thickness of the WS2-WO3 composite film was measured to be approximately 1.8 μm, and the atomic percentage of introduced W was 2 at.%.

[0039] The WS2-WO3 composite film was stored at 30℃ and 90%RH in a humid air environment for 120 hours (modification) to obtain a modified WS2-WO3 composite film. The atomic percentage of O in the modified film was determined to be 58 at.%.

[0040] Example 2 9Cr18 steel was selected as the substrate material and ultrasonically cleaned sequentially in petroleum ether, anhydrous ethanol, and acetone for 15 minutes each. The cleaned substrate was then dried with 99.9% pure nitrogen gas and fixed on a sample holder within a vacuum chamber. The substrate temperature was adjusted to 100℃, and the vertical distance between the substrate and the sputtering target was 100 mm. The chamber was then evacuated until the background vacuum reached 1.0 × 10⁻⁶ mm. -3 At Pa, an appropriate amount of argon gas is introduced into the chamber and the working pressure is maintained at 8.0 Pa. A bias voltage of -500V is applied to perform Ar ion etching and cleaning on the substrate for 15 minutes.

[0041] Argon was used as the working gas, and the argon flow rate was adjusted to 30 sccm. The main pumping valve was adjusted to control the vacuum rate, maintaining the pressure in the vacuum chamber at 5.0 Pa. The substrate bias was adjusted to -30 V, and the sample holder was started to rotate at a constant speed of 2.0 r / min. Radio frequency co-sputtering was used to deposit WS2 targets with a purity of 99.9% and TiO2 targets with a purity of 99.99%, respectively. The sputtering power of the WS2 target was 200 W, and the sputtering power of the TiO2 target was 100 W. After continuous sputtering for 30 min, the substrate was cooled to room temperature (25 °C) to form a disulfide-based composite film on the substrate surface, denoted as WS2-TiO2 composite film. The thickness of the WS2-TiO2 composite film was measured to be approximately 2 μm, and the atomic percentage of introduced Ti was 1 at.%.

[0042] The WS2-TiO2 composite film was stored at 30℃ and 90%RH in a humid air environment for 120 hours (modification) to obtain a modified WS2-TiO2 composite film. The atomic percentage of O in the modified film was measured to be 42 at.%.

[0043] Example 3 9Cr18 steel was selected as the substrate material and ultrasonically cleaned sequentially in petroleum ether, anhydrous ethanol, and acetone for 15 minutes each. The cleaned substrate was then dried with 99.9% pure nitrogen gas and fixed on a sample holder within a vacuum chamber. The substrate temperature was adjusted to 100℃, and the vertical distance between the substrate and the sputtering target was 80 mm. The chamber was then evacuated until the background vacuum reached 1.0 × 10⁻⁶ mm. -3When the pressure is below Pa, introduce an appropriate amount of argon gas into the room and maintain the working pressure at 8.0 Pa. Apply a bias voltage of -500V to perform Ar ion etching cleaning on the substrate for 15 minutes.

[0044] Argon was used as the working gas, and the argon flow rate was adjusted to 30 sccm. The main pumping valve was adjusted to control the vacuum rate, maintaining the pressure in the vacuum chamber at 5.0 Pa. The substrate bias was set to -50 V, and the sample holder was started to rotate at a constant speed of 4.0 r / min. Radio frequency co-sputtering was used to deposit WS2 targets with a purity of 99.9% and CaO targets with a purity of 99.5%, with a sputtering power of 200 W for the WS2 target and 50 W for the CaO target. After continuous sputtering for 30 min, the substrate was cooled to room temperature (25 °C) to form a disulfide-based composite film on the substrate surface, denoted as WS2-CaO composite film. The thickness of the WS2-CaO composite film was measured to be approximately 1.3 μm, and the atomic percentage of introduced Ca was 2 at.%.

[0045] The WS2-CaO composite film was stored at 30℃ and 90%RH in a humid air environment for 120 hours (modification) to obtain a modified WS2-CaO composite film. The atomic percentage of O in the modified film was determined to be 60 at.%.

[0046] Example 4 9Cr18 steel was selected as the substrate material and ultrasonically cleaned sequentially in petroleum ether, anhydrous ethanol, and acetone for 15 minutes each. The cleaned substrate was then dried with 99.9% pure nitrogen gas and fixed on a sample holder within a vacuum chamber, ensuring a vertical distance of 70 mm between the substrate and the sputtering target. The chamber was then evacuated, and the substrate temperature was adjusted to 80°C until the background vacuum reached 1.0 × 10⁻⁶. -3 At Pa, an appropriate amount of argon gas is introduced into the chamber and the working pressure is maintained at 8.0 Pa. A bias voltage of -500V is applied to perform Ar ion etching and cleaning on the substrate for 15 minutes.

[0047] Argon was used as the working gas, and the argon flow rate was adjusted to 30 sccm. The main pumping valve was adjusted to control the vacuum rate, maintaining the pressure in the vacuum chamber at 3.0 Pa. The substrate bias was adjusted to -40 V, and the sample holder was started to rotate at a constant speed of 3.0 r / min. Radio frequency co-sputtering was used to deposit WS2 targets with a purity of 99.9% and MoO3 targets with a purity of 99.99%. The sputtering power of the WS2 target was 200 W, and the radio frequency power of the MoO3 target was 40 W. After continuous sputtering for 30 min, the substrate was cooled to room temperature (25 °C) to form a disulfide-based composite film on the substrate surface, denoted as WS2-MoO3 composite film. The thickness of the film was measured to be approximately 2.3 μm, and the atomic percentage of introduced Mo was 1.5 at.%.

[0048] The WS2-MoO3 composite film was stored at 30℃ and 90%RH in a humid air environment for 120 hours (modification) to obtain a modified WS2-MoO3 composite film. The atomic percentage of O in the modified film was determined to be 39 at.%.

[0049] Comparative Example 1 9Cr18 steel was selected as the substrate material and ultrasonically cleaned sequentially in petroleum ether, anhydrous ethanol, and acetone for 15 minutes each. The cleaned substrate was then dried with 99.9% pure nitrogen gas and fixed on a sample holder within a vacuum chamber. The substrate temperature was adjusted to 100℃, and the vertical distance between the substrate and the sputtering target was 80 mm. The chamber was then evacuated until the background vacuum reached 1.0 × 10⁻⁶ mm. -3 At Pa, an appropriate amount of argon gas is introduced into the chamber and the working pressure is maintained at 8.0 Pa. A bias voltage of -500V is applied to perform Ar ion etching and cleaning on the substrate for 15 minutes.

[0050] Using argon as the working gas, the argon flow rate was adjusted to 30 sccm. The main pumping valve was adjusted to control the vacuum rate, maintaining the pressure inside the vacuum chamber at 5.0 Pa. The substrate bias was set to -20 V, and the sample holder was started to rotate at a constant speed of 2.0 r / min. The RF sputtering power was turned on, and the sputtering power of the WS2 target was set to 200 W. Sputtering was performed for 30 min, followed by cooling to room temperature (25 °C). Finally, a WS2 thin film was formed on the substrate surface. The thickness of the WS2 thin film was measured to be approximately 2.1 μm. The modified WS2 film was obtained by storing the WS2 film in a humid air environment at 30℃ and 90%RH for 120 hours.

[0051] The WS2 thin film prepared in Comparative Example 1 and the modified WS2 thin film were subjected to XRD tests, and the test results are as follows. Figure 1 As shown. By Figure 1It can be seen that the modified WS2 film exhibits WO3 diffraction peaks due to the influence of humid air storage, and the (002) crystal plane in the film shows a significant low-angle shift.

[0052] XPS tests were performed on the WS2 thin film prepared in Comparative Example 1 and the modified WS2 thin film at different etching times. The test results are as follows: Figure 2 As shown. By Figure 2 It can be seen that the XPS spectra of the modified WS2 film at different etching times show a more obvious WO3 peak at the binding energy of 38eV compared with the XPS spectra of the WS2 film. This indicates that the modified WS2 film underwent deep oxidation from the surface to the interior after being stored in a humid heat environment.

[0053] The WS2 film prepared in Comparative Example 1 and the modified WS2 film were subjected to vacuum ball-and-disc tribological tests (load 5N, disk rotation speed 1000r / min, rotation radius 5mm). The obtained friction curves are shown below. Figure 3 As shown. By Figure 3 It can be seen that the WS2 film prepared in Comparative Example 1 exhibits an average friction coefficient of about 0.05 and a stable friction state; the modified WS2 film exhibits an average friction coefficient of about 0.02, but the friction coefficient fluctuates greatly during the friction process, and the film friction state is unstable. This indicates that although humid heat storage conditions can reduce the friction coefficient of the WS2 film, the friction coefficient of the film fluctuates greatly, and the lubrication effect of the film is unstable.

[0054] The WS2 film prepared in Comparative Example 1 was subjected to a 5 N load, a chassis rotation speed of 1000 r / min, and a rotation radius of 5 mm for 5.0 × 10⁻⁶ cycles. 4 After one sliding cycle, the friction interface was tested by transmission electron microscopy. The test results are as follows: Figure 4 As shown, (a) is the microstructure of the transfer film at the WS2 thin film friction interface, with a thickness of 24.4 nm; (b) is a magnified view of the transfer film structure in (a), showing that a WS2 crystal layer with a (002) crystal plane orientation is formed in the transfer film; (c) is the microstructure of the friction film, with a thickness of 47.9 nm; and (d) is a magnified view of the surface of the friction film in (c), showing that a WS2 crystal layer with a (002) orientation also appears on the surface of the friction film. Figure 4 It can be seen that the WS2 film exhibits a friction interface with relative sliding of the WS2 (002) crystal plane. There are a large number of crystal defects in this friction interface, and there is a grain boundary pinning effect, which makes the film exhibit a high average friction coefficient (about 0.05).

[0055] The modified WS2 film prepared in Comparative Example 1 was subjected to a 5 N load, a chassis rotation speed of 1000 r / min, and a rotation radius of 5 mm for 5.0 × 10⁻⁶ cycles.4 After one sliding cycle, the friction interface was tested by transmission electron microscopy. The test results are as follows: Figure 5 As shown, (a) is the microstructure of the modified WS2 thin film transfer film, with a thickness of approximately 86.4 nm; (b) is a magnified view of a portion of the transfer film in (a), showing WO3 nanoparticles with a diameter of 33.6 nm formed on the surface of the transfer film; (c) is the microstructure of the modified WS2 thin film friction film; and (d) is a magnified view of a portion of the friction film structure in (c), showing WO3 nanoparticles with a diameter of approximately 27.3 nm still appearing on the surface of the friction film. Figure 5 It can be seen that the modified WS2 film exhibits a friction interface dominated by WO3 nanoparticles, which transforms the traditional sliding friction into a rolling-sliding mixed friction, reducing the frictional resistance and thus making the film exhibit a low average coefficient of friction (about 0.02).

[0056] The WS2-WO3 composite film prepared in Example 1 and the modified WS2-WO3 composite film were subjected to XRD tests, and the test results are as follows. Figure 6 As shown. By Figure 6 It can be seen that the WS2-WO3 composite film still has a certain degree of crystallinity, but its crystallinity is significantly lower than that of the pure WS2 film. The modified WS2-WO3 composite film also showed diffraction peaks of the WO3 (100) crystal plane due to the influence of humid air storage. Here, WO3 is an oxide formed by the humid heat modification of disulfide.

[0057] The WS2-WO3 composite film prepared in Example 1 and the modified WS2-WO3 composite film were subjected to vacuum tribological property testing. The test conditions were: a load of 5 N, a chassis rotation speed of 1000 r / min, and a rotation radius of 5 mm. The obtained friction curves are shown below. Figure 7 As shown. By Figure 7 It can be seen that the average friction coefficient of the WS2-WO3 composite film is about 0.06; the average friction coefficient of the modified WS2-WO3 composite film is about 0.025, and the friction coefficient fluctuates little, indicating good stability.

[0058] The WS2-TiO2 composite film prepared in Example 2 and the modified WS2-TiO2 composite film were subjected to XRD tests, and the test results are as follows. Figure 8 As shown. By Figure 8 It can be seen that the WS2-TiO2 composite film prepared in Example 2 has obvious crystallinity; after the modified WS2-TiO2 composite film is stored in humid air, the WS2 (002) crystal plane shifts at a low angle and the diffraction peak of the WO3 (100) crystal plane appears.

[0059] The WS2-TiO2 composite film prepared in Example 2 and the modified WS2-TiO2 composite film were subjected to XPS tests at different etching times. The test results are as follows: Figure 9 As shown. By Figure 9 It can be seen that the XPS spectra of the modified WS2-TiO2 composite film at different etching times show a more obvious WO3 peak at the binding energy of 38eV compared with the XPS spectra of the WS2-TiO2 composite film. This indicates that the modified WS2-TiO2 composite film underwent deep oxidation from the surface to the interior after humid heat storage.

[0060] The WS2-TiO2 composite film prepared in Example 2 and the modified WS2-TiO2 composite film were subjected to vacuum tribological property testing. The test conditions were: a load of 5 N, a chassis rotation speed of 1000 r / min, and a rotation radius of 5 mm. The obtained friction curves are shown below. Figure 10 As shown. By Figure 10 It can be seen that the average friction coefficient of the WS2-TiO2 composite film is about 0.056; the average friction coefficient of the modified WS2-TiO2 composite film is about 0.018, and the friction coefficient fluctuates little, showing good stability.

[0061] The WS2-TiO2 composite film prepared in Example 2 was subjected to a 5 N load, a chassis rotation speed of 1000 r / min, and a rotation radius of 5 mm for 5.0 × 10⁻⁶ cycles. 4 After one sliding cycle, the friction interface was tested by transmission electron microscopy. The test results are as follows: Figure 11 As shown, (a) is the microstructure of the modified WS2-TiO2 composite thin film transfer film, with a thickness of approximately 116.5 nm; (b) is a magnified view of a portion of the transfer film in (a), showing WO3 nanoparticles with a diameter of 15.0 nm formed on the surface of the transfer film; (c) is the microstructure of the modified WS2-TiO2 thin film friction film; and (d) is a magnified view of a portion of the friction film structure in (c), showing WO3 nanoparticles with a diameter of approximately 4.4 nm still appearing on the surface of the friction film. Figure 11 It can be seen that the modified WS2-TiO2 composite film exhibits a friction interface dominated by WO3 nanoparticles, which changes the motion mode of friction shear. At the same time, the WO3 nanoparticles of appropriate size reduce the friction resistance, thereby further reducing the friction coefficient of the film.

[0062] The WS2-CaO composite film prepared in Example 3 and the modified WS2-CaO composite film were subjected to XRD tests, and the test results are as follows. Figure 12 As shown. By Figure 12It can be seen that the WS2-CaO composite film still has a certain degree of crystallinity; diffraction peaks of the WS2 (002) crystal plane and the WO3 (100) crystal plane appear in the modified WS2-CaO composite film.

[0063] The WS2-CaO composite film prepared in Example 3 and the modified WS2-CaO composite film were subjected to vacuum tribological property testing. The test conditions were: a load of 5 N, a chassis rotation speed of 1000 r / min, and a rotation radius of 5 mm. The resulting tribological curves are shown below. Figure 13 As shown. By Figure 13 It can be seen that the average friction coefficient of the WS2-CaO composite film is about 0.04; the average friction coefficient of the modified WS2-CaO composite film is about 0.015, and the friction coefficient has good stability.

[0064] The WS2-MoO3 composite film prepared in Example 4 and the modified WS2-MoO3 composite film were subjected to vacuum tribological property testing. The test conditions were: a load of 5 N, a chassis rotation speed of 1000 r / min, and a rotation radius of 5 mm. The resulting tribological curves are shown below. Figure 14 As shown. By Figure 14 It can be seen that the average friction coefficient of the WS2-MoO3 composite film is about 0.06; the average friction coefficient of the modified WS2-MoO3 composite film is about 0.02, and the friction coefficient has good stability.

[0065] 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 modified disulfide-based composite film, characterized in that, It includes a matrix and a first metal oxide and a second metal oxide dispersed in the matrix; The first metal oxide includes one or more of WO3, TiO2, CaO, MoO3, Ta2O5, In2O3, Nb2O5, ZrO2, Cr2O3, and HaO2; The metal element in the second metal oxide is the same as the metal element in the matrix.

2. The modified disulfide-based composite film according to claim 1, characterized in that, The atomic percentage of the metal element in the first metal oxide in the modified disulfide-based composite film is 1-5%.

3. The modified disulfide-based composite film according to claim 1, characterized in that, The second metal oxide is spherical at the friction interface, and the diameter of the sphere is 3~50nm.

4. The modified disulfide-based composite film according to claim 1, characterized in that, The substrate includes a WS2 thin film or a MoS2 thin film.

5. The modified disulfide-based composite film according to claim 1, characterized in that, The thickness of the modified disulfide-based composite film is 0.5~3μm.

6. The method for preparing the modified disulfide-based composite film according to any one of claims 1 to 5, characterized in that, Includes the following steps: A disulfide-based composite film is obtained by simultaneously sputtering a disulfide target and a metal oxide target on the substrate surface; the metal oxide target includes one or more of WO3 target, TiO2 target, CaO target, MoO3 target, Ta2O5 target, In2O3 target, Nb2O5 target, ZrO2 target, Cr2O3 target and HaO2 target. The disulfide-based composite film was modified by placing it in a humid and hot environment to obtain the modified disulfide-based composite film.

7. The preparation method according to claim 6, characterized in that, The disulfide target includes a tungsten disulfide target or a molybdenum disulfide target; The sputtering includes radio frequency magnetron sputtering; the conditions for radio frequency magnetron sputtering include: argon as the working gas, argon flow rate of 20~90 sccm, working gas pressure of 1~10 Pa, substrate bias of -60~-10 V, substrate rotation speed of 1~6 r / min, substrate temperature of 50~600℃, vertical distance between the target and the substrate of 50~100 mm, sputtering power of disulfide target of 100~300 W, sputtering power of metal oxide of 10~200 W, and sputtering time of 20~40 min.

8. The preparation method according to claim 6, characterized in that, The process before sputtering also includes: sequentially ultrasonically cleaning and drying the substrate, then fixing it on a sample holder for argon ion etching cleaning. The working gas pressure for the argon ion etching cleaning is 5~9 Pa, the bias voltage is -800~-400 V, and the time is 14~16 min.

9. The preparation method according to claim 6, characterized in that, The temperature of the humid and hot environment is 5~50℃, and the relative humidity is 10~100%RH; the modification time is 1~10000h; The substrate includes 9Cr18 steel, bearing steel, or carbon steel.

10. The application of the modified disulfide-based composite film according to any one of claims 1 to 5 or the modified disulfide-based composite film prepared by the preparation method according to any one of claims 6 to 9 as a solid lubricating material.

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