A chalcogenide composite thin film and a preparation method and application thereof

Abstract

This invention provides a dichalcogenide composite film, its preparation method, and its applications, relating to the field of solid lubricant materials technology. The invention provides a dichalcogenide composite film comprising a transition metal dichalcogenide compound and a dopant doped in the transition metal dichalcogenide compound; the dopant includes a dopant metal, which includes tin, bismuth, or a tin-bismuth alloy. By doping the transition metal dichalcogenide compound with tin, bismuth, or a tin-bismuth alloy, this invention can further improve the dichalcogenide film's resistance to humid environments, reduce the coefficient of friction of the dichalcogenide composite film in humid environments, and extend its wear life. As a solid lubricant, it has excellent application prospects in diverse environments such as storage, running-in, and transportation of mechanical moving parts. This invention uses a sputtering method to prepare the dichalcogenide composite film, which is simple, effective, low-cost, environmentally friendly, and suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of solid lubricant materials technology, specifically to a disulfide composite film, its preparation method, and its application. Background Technology

[0002] Disulfide lubricants are widely used in various mechanical moving components in vacuum environments to reduce wear between mating materials, decrease debris generation, and lower energy consumption. However, due to their inherent crystal structure, particularly molybdenum disulfide and tungsten disulfide, disulfide solid materials, when used as solid lubricant films, exhibit highly reactive "facets" that can react with water vapor and oxygen in the atmosphere. This reaction disrupts the composition and structure of molybdenum disulfide, leading to a sharp decline in its lubricating performance and rapid failure. Therefore, improving the resistance of disulfide solid lubricant film materials to humid environments is a current research focus in the field of friction.

[0003] Currently, common methods to improve the resistance of disulfide solid lubricating film materials to humid environments include increasing the film density and doping with metallic elements (such as noble metals, titanium, lead, etc.). However, the wear life of these materials is relatively short, limiting their application in diverse environments such as storage, running-in, and transportation of mechanical moving parts. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a dichalcogenide composite film, its preparation method, and its application. The dichalcogenide composite film provided by this invention has a low coefficient of friction and a long wear resistance life in humid environments.

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

[0006] The present invention provides a dichalcogenide composite thin film comprising a transition metal dichalcogenide compound and a dopant doped in the transition metal dichalcogenide compound; the dopant comprises a doped metal, wherein the doped metal comprises tin, bismuth or a tin-bismuth alloy.

[0007] Preferably, the mass content of the doped metal in the dichalcogenide composite film is 0.5% to 20%.

[0008] Preferably, the transition metal dichalcogenide compound comprises a transition metal and a chalcogenide element;

[0009] The transition metal includes at least one of molybdenum, tungsten, and niobium;

[0010] The chalcogens include at least one of sulfur and selenium.

[0011] Preferably, the transition metal dichalcogenide includes at least one of molybdenum disulfide, tungsten disulfide, and niobium diselenide.

[0012] Preferably, the dopant further includes nitrogen; the mass content of nitrogen in the dichalcogenide composite film is ≤2%.

[0013] The present invention also provides a method for preparing the dichalcogenide composite thin film described above, comprising the following steps: using a transition metal dichalcogenide compound and a doped metal as targets, sputtering is performed to obtain the dichalcogenide composite thin film; the sputtering atmosphere includes an inert gas.

[0014] Preferably, the sputtering atmosphere further includes nitrogen;

[0015] The nitrogen content in the sputtering atmosphere is 0.1% to 20%.

[0016] Preferably, the sputtering pressure is 0.2–10 Pa and the bias voltage is 0–600 V.

[0017] Preferably, the application mode using transition metal dichalcogenides and doped metals as targets is a dual-target independent mode; when using the dual-target independent mode, the sputtering power density of the transition metal dichalcogenide target during the sputtering process is 2–160 kW / m². 2 The sputtering power density of the doped metal target is 1–40 kW / m². 2 .

[0018] The present invention also provides the application of the disulfide composite film described in the above technical solution or the disulfide composite film prepared by the above technical solution in mechanical moving parts or vacuum anti-cold welding materials.

[0019] This invention provides a dichalcogenide composite film, comprising a transition metal dichalcogenide compound and a dopant doped in the transition metal dichalcogenide compound; the dopant includes a dopant metal, which includes tin, bismuth, or a tin-bismuth alloy. By doping the transition metal dichalcogenide compound with tin, bismuth, or a tin-bismuth alloy, this invention further improves the humid environment resistance of the dichalcogenide film. The dichalcogenide composite film exhibits a low coefficient of friction and long wear life in humid environments, making it a promising solid lubricant for use in diverse environments such as storage, running-in, and normal operation of mechanical moving parts.

[0020] This invention uses a sputtering method to prepare dichalcogenide composite films. The preparation method is simple, effective, low-cost, environmentally friendly, and suitable for industrial production. Attached Figure Description

[0021] Figure 1 Typical friction curves of the molybdenum disulfide-based composite film obtained in Example 1;

[0022] Figure 2The scratch curve of the molybdenum disulfide-based composite film obtained in Example 1;

[0023] Figure 3 Typical friction curves of the tungsten disulfide-based composite film obtained in Example 2;

[0024] Figure 4 Typical friction curves of the molybdenum disulfide-based composite film obtained in Example 3;

[0025] Figure 5 Typical friction curves of the tungsten disulfide-based composite film obtained in Example 4;

[0026] Figure 6 The scratch curve of the tungsten disulfide-based composite film obtained in Example 4;

[0027] Figure 7 The image shows a typical friction curve of the molybdenum disulfide thin film obtained in Comparative Example 1. Detailed Implementation

[0028] The present invention provides a dichalcogenide composite thin film comprising a transition metal dichalcogenide compound and a dopant doped in the transition metal dichalcogenide compound; the dopant comprises a doped metal, wherein the doped metal comprises tin, bismuth or a tin-bismuth alloy.

[0029] In this invention, the transition metal dichalcogenide preferably comprises a transition metal and a chalcogenide; the transition metal preferably comprises at least one of molybdenum (Mo), tungsten (W), and niobium (Nb); the chalcogenide preferably comprises at least one of sulfur (S) and selenium (Se). In this invention, the transition metal dichalcogenide preferably comprises at least one of molybdenum disulfide, tungsten disulfide, and niobium diselenide.

[0030] In this invention, the mass content of the doped metal in the dichalcogenide composite film is preferably 0.5% to 20%, and in specific embodiments it can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%. In this invention, the mass ratio of tin to bismuth in the tin-bismuth alloy is preferably 1:0.2 to 4, and in specific embodiments it can be 1:0.2, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, or 1:4.

[0031] In this invention, the dopant preferably further includes nitrogen. When nitrogen is present, the chemical composition of the dichalcogenide composite film is SnBi / N / MS2, where MS2 is a transition metal dichalcogenide compound. The mass content of nitrogen in the dichalcogenide composite film is preferably ≤2%, and in specific embodiments it can be 0%, 0.1%, 0.5%, 1%, 1.5%, or 2%. In this invention, nitrogen can improve the hardness of the dichalcogenide composite film; however, excessive nitrogen doping will increase the coefficient of friction and reduce the wear life of the dichalcogenide composite film. This invention controls the mass content of nitrogen in the dichalcogenide composite film to below 2%, enabling the dichalcogenide composite film to achieve both high hardness and low coefficient of friction.

[0032] In this invention, the thickness of the disulfide composite film is preferably 1–7 μm. In specific embodiments, it can be 1 μm, 2 μm, 3 μm, 3.2 μm, 4 μm, 4.2 μm, 4.8 μm, 5 μm, 6 μm, or 7 μm.

[0033] The present invention also provides a method for preparing the dichalcogenide composite thin film described above, comprising the following steps: using a transition metal dichalcogenide compound and a doped metal as targets, sputtering is performed to obtain the dichalcogenide composite thin film; the sputtering atmosphere includes an inert gas.

[0034] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0035] In this invention, the sputtering preferably includes DC sputtering, DC magnetron sputtering, radio frequency sputtering, radio frequency magnetron sputtering, or intermediate frequency magnetron sputtering. In this invention, during the sputtering process, a transition metal dichalcogenide compound and a doped metal form the dichalcogenide composite film on the target substrate. This invention does not impose any particular limitation on the type of substrate; any substrate well-known to those skilled in the art can be used.

[0036] In this invention, the sputtering atmosphere includes an inert gas, preferably argon or helium. The sputtering atmosphere also preferably includes nitrogen; the nitrogen content in the sputtering atmosphere is preferably 0.1% to 20%, and in specific embodiments can be 0.1%, 0.5%, 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%. In this invention, the nitrogen in the dopant originates from the nitrogen in the sputtering atmosphere.

[0037] In this invention, it is preferable to first evacuate the vacuum chamber to a background vacuum, and then introduce the sputtering atmosphere. In this invention, the preferred vacuum level of the background vacuum is 5 × 10⁻⁶. -4 ~8×10-3 Pa, in a specific embodiment, can be 5 × 10 -4 Pa, 1×10 -3 Pa, 2×10 -3 Pa, 3×10 -3 Pa, 4×10 -3 Pa, 5×10 -3 Pa, 6×10 -3 Pa, 7×10 -3 Pa or 8×10 -3 Pa.

[0038] In this invention, the sputtering pressure is preferably 0.2 to 10 Pa, and in specific embodiments it can be 0.2 Pa, 0.5 Pa, 1 Pa, 4 Pa, 5 Pa, 6 Pa, 8 Pa or 10 Pa; the sputtering bias voltage is preferably 0 to 600 V, and in specific embodiments it can be 0 V, 10 V, 20 V, 50 V, 100 V, 200 V, 300 V, 400 V, 500 V or 600 V.

[0039] In this invention, the application mode using transition metal dichalcogenides and doped metals as targets is a dual-target independent mode. In this invention, when using the dual-target independent mode, the sputtering power density of the transition metal dichalcogenide target during the sputtering process is preferably 2–160 kW / m². 2 In a specific embodiment, it can be 2kW / m 2 4kW / m 2 5kW / m 2 10kW / m 2 12kW / m 2 20kW / m 2 30kW / m 2 40kW / m 2 50kW / m 2 60kW / m 2 70kW / m 2 80kW / m 2 90kW / m 2 100kW / m 2 110kW / m 2 120kW / m 2 130kW / m 2 140kW / m 2 150kW / m 2 Or 160kW / m 2 The sputtering power density of the doped metal target is preferably 1–40 kW / m³. 2 In a specific embodiment, it can be 1kW / m 2 2kW / m2 3kW / m 2 4kW / m 2 5kW / m 2 6kW / m 2 7kW / m 2 8kW / m 2 9kW / m 2 10kW / m 2 15kW / m 2 Or 20kW / m 2 .

[0040] The present invention does not have a special limitation on the sputtering time; it can be selected and adjusted according to the required thickness of the disulfide composite film.

[0041] This invention also provides the application of the disulfide composite film described in the above-described technical solutions, or the disulfide composite film prepared by the above-described preparation methods, in mechanical moving parts or vacuum anti-cold welding materials. In this invention, the disulfide composite film is preferably used as a solid lubricant in one or more of the following applications: anti-cold welding, lubrication, storage, running-in, and transportation of mechanical moving parts. The disulfide composite film provided by this invention has excellent application prospects in diverse environments such as storage, running-in, and transportation of mechanical moving parts, especially in humid atmospheric environments.

[0042] To further illustrate the present invention, the dichalcogenide composite film, its preparation method, and its application provided by the present invention are described in detail below with reference to embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0043] Example 1

[0044] Using molybdenum disulfide and tin-bismuth alloy targets (tin to bismuth mass ratio = 1:2.5) as independent targets, the vacuum chamber was evacuated to 5.0 × 10⁻⁶. -3 A base vacuum of Pa was established, followed by the introduction of argon gas to adjust the pressure to 4.0 Pa. Radio frequency sputtering was then employed, achieving a power density of 4 W / cm² for the molybdenum disulfide target sputtering. 2 The sputtering power density of the tin-bismuth alloy target is 1 W / cm². 2 The sputtering bias voltage was 50V and the sputtering time was 30min. A molybdenum disulfide-based composite film with a thickness of 3.2μm was obtained on the surface of the polished steel sheet, wherein the mass percentage of tin and bismuth was 1.6%.

[0045] The tribological properties of molybdenum disulfide composite films in a humid atmospheric environment with 45% RH were tested using a vacuum ball-and-disc testing machine. The experimental conditions were: 5 N normal load and sliding speed of 1000 r / min. The test results are shown below. Figure 1It can be seen that the average coefficient of friction of the molybdenum disulfide-based composite film in a humid environment is 0.054, and its wear life can reach 8.0 × 10⁻⁶ in an atmospheric environment with 46% RH. 5 The result indicates that the molybdenum disulfide-based composite film has a low coefficient of friction and a long wear-resistant life in humid environments.

[0046] The bonding strength between the molybdenum disulfide composite film and the substrate was tested using a scratch tester. The experimental conditions were: 100 N loading load, 100 N / min loading speed, and a scratch length of 5 mm. The test results are shown in [Figure number missing]. Figure 2 It can be seen that the bonding strength between the molybdenum disulfide-based composite film and the substrate reaches 35N.

[0047] Example 2

[0048] Using tungsten disulfide and tin-bismuth alloy targets (tin to bismuth mass ratio = 1:2) as independent targets, the vacuum chamber was evacuated to 5.0 × 10⁻⁶. -3 A base vacuum of 5.0 Pa was established, followed by the introduction of argon gas to adjust the pressure to 5.0 Pa. Radio frequency sputtering was then employed, achieving a power density of 4 W / cm² for the tungsten disulfide target sputtering. 2 The sputtering power density of the gold sputtering target is 1 W / cm². 2 The sputtering bias voltage was 20V and the sputtering time was 30min. A tungsten disulfide-based composite film with a thickness of 4.2μm was obtained on the surface of the polished steel sheet, wherein the mass percentage of tin and bismuth was 1.8%.

[0049] The tribological properties of tungsten disulfide-based composite films in a vacuum environment were tested using a vacuum ball-and-disc testing machine. The experimental conditions were: 5N normal load, sliding speed 1000 r / min. The sample was taken from the bearing steel ball under a vacuum better than 5.0 × 10⁻⁶. -3 Pa. Test results are shown below. Figure 3 It can be seen that the average friction coefficient of the molybdenum disulfide-based composite film in a vacuum environment is 0.021.

[0050] Example 3

[0051] Using molybdenum disulfide and tin-bismuth alloy targets (tin to bismuth mass ratio = 1:2) as independent targets, the vacuum chamber was evacuated to 5.0 × 10⁻⁶. -3 A base vacuum of 4.0 Pa was established, followed by the introduction of argon and nitrogen gas, with nitrogen at 2% of the total pressure. The pressure was adjusted to 4.0 Pa, and radio frequency sputtering was employed, with a power density of 4 W / cm² for the molybdenum disulfide target sputtering. 2 The sputtering power density of the gold sputtering target is 1 W / cm². 2The sputtering bias voltage was 50V and the sputtering time was 30min. A molybdenum disulfide-based composite film with a thickness of 3.2μm was obtained on the surface of the polished steel sheet, wherein the mass percentage of tin-bismuth alloy was 1.6% and the mass percentage of nitrogen was 0.1%.

[0052] The tribological properties of molybdenum disulfide composite films in a humid atmospheric environment with 60% RH were tested using a vacuum ball-and-disc testing machine. The experimental conditions were: 5 N normal load and sliding speed of 1000 r / min. The test results are shown below. Figure 4 It can be seen that the coefficient of friction of the molybdenum disulfide-based composite film is 0.028 in a humid environment, and its wear life can reach 6.5 × 10⁻⁶ in an atmospheric environment with 60% RH. 5 change.

[0053] Example 4

[0054] Using molybdenum disulfide and tin-bismuth alloy targets (tin to bismuth mass ratio = 1:1) as independent targets, the vacuum chamber was evacuated to 5.0 × 10⁻⁶. -3 A base vacuum of Pa was established, followed by the introduction of argon and nitrogen gases, with nitrogen at 2% of the total pressure. The pressure was adjusted to 4.0 Pa, and radio frequency sputtering was employed, with a power density of 12 W / cm² for the molybdenum disulfide target sputtering. 2 The sputtering power density of the tin-bismuth alloy target is 1 W / cm². 2 The sputtering bias voltage was 50V and the sputtering time was 30min. A molybdenum disulfide-based composite film with a thickness of 4.8μm was obtained on the surface of the polished steel sheet, wherein the mass percentage of tin-bismuth alloy was 1.5%.

[0055] The tribological properties of molybdenum disulfide-based composite films in a humid atmospheric environment with 20% RH were tested using a vacuum ball-and-disc testing machine. The experimental conditions were: 5 N normal load and sliding speed of 1000 r / min. The results are shown in [Figure number missing]. Figure 5 It can be seen that the coefficient of friction of the molybdenum disulfide-based composite film is 0.011, and its wear life can reach 8.0 × 10⁻⁶ in an atmospheric environment with 20% RH. 5 The result indicates that the molybdenum disulfide-based composite film has a low coefficient of friction and a long wear-resistant life in humid environments.

[0056] The bonding strength between the molybdenum disulfide composite film and the substrate was tested according to the method in Example 1. The test results are shown in [Figure 1]. Figure 6 It can be seen that the bonding strength between the molybdenum disulfide-based composite film and the substrate reaches 65N.

[0057] Comparative Example 1

[0058] Using molybdenum disulfide as the target material, the vacuum chamber was evacuated to 5.0 × 10⁻⁶. -3A base vacuum of Pa was established, followed by the introduction of argon and nitrogen gas, with nitrogen pressure accounting for 2% of the total pressure. The pressure was adjusted to 4.0 Pa, and radio frequency sputtering was employed, with a power density of 8 W / cm² for the molybdenum disulfide target sputtering. 2 The sputtering bias voltage was 30V and the sputtering time was 30min, resulting in a 4.2μm thick molybdenum disulfide-based composite film on the surface of a polished steel sheet.

[0059] The tribological properties of the sample were tested using a vacuum ball-and-disc testing machine in a humid atmospheric environment with 40% RH. The experimental conditions were: 5 N normal load and sliding speed of 1000 r / min. The results are shown in [Figure number missing]. Figure 7 It can be seen that the coefficient of friction of the molybdenum disulfide-based composite film is 0.14, and the number of friction cycles is relatively low, only 5.0 × 10⁻⁶. 4 change.

[0060] 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 dichalcogenide composite film, characterized in that, The film comprises a transition metal dichalcogenide compound and a dopant doped in the transition metal dichalcogenide compound; the transition metal dichalcogenide compound includes at least one of molybdenum disulfide and tungsten disulfide; the dopant includes a doped metal, wherein the doped metal is a tin-bismuth alloy; the mass content of the doped metal in the dichalcogenide composite film is 0.5-2%; the mass ratio of tin to bismuth in the tin-bismuth alloy is 1:0.2-4.

2. The dichalcogenide composite film according to claim 1, characterized in that, The dopant also includes nitrogen; the mass content of nitrogen in the dichalcogenide composite film is ≤2%.

3. The method for preparing the dichalcogenide composite film according to any one of claims 1 to 2, characterized in that, Includes the following steps: The dichalcogenide composite film is obtained by sputtering using a transition metal dichalcogenide compound and a doped metal as the target material; the sputtering atmosphere includes an inert gas.

4. The preparation method according to claim 3, characterized in that, The sputtering atmosphere also includes nitrogen; The nitrogen content in the sputtering atmosphere is 0.1% to 20%.

5. The preparation method according to claim 3 or 4, characterized in that, The sputtering pressure is 0.2~10Pa and the bias voltage is 0~600V.

6. The preparation method according to claim 3, characterized in that, The application mode of the transition metal dichalcogen compound and the doping metal as the target material is a double-target independent mode; when the double-target independent mode is adopted, in the sputtering process, the sputtering power density of the transition metal chalcogenide target material is 2-160 kW / m 2 , and the sputtering power density of the doping metal target material is 1-40 kW / m 2 .

7. The application of the disulfide composite film according to any one of claims 1 to 2 or the disulfide composite film prepared by the preparation method according to any one of claims 3 to 6 in mechanical moving parts or vacuum anti-cold welding materials.

Images