Disulfide composite film and preparation method and application thereof

Abstract

The invention provides a disulfide composite film as well as a preparation method and application thereof, and relates to the technical field of solid lubricating materials. The invention provides a disulfide composite film. The disulfide composite film comprises a transition metal disulfide compound and a dopant doped in the transition metal disulfide compound, the dopant comprises a doped metal, and the doped metal comprises tin, bismuth or a tin-bismuth alloy. Tin, bismuth or tin-bismuth alloy is doped in the transition metal disulfide compound, so that the humid environment resistance of the disulfide film can be further improved, the friction coefficient of the disulfide composite film in a humid environment can be reduced, the wear-resistant life is prolonged, and the service life of the disulfide composite film is prolonged. As a solid lubricating material, the solid lubricating material has a good application prospect in various environments such as storage, running-in and transfer of mechanical moving parts. The dichalcogenide composite film is prepared by adopting a sputtering method, and the preparation method is simple, effective, low in cost, green, environment-friendly and suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of solid lubricant materials, and particularly relates to a chalcogen composite film, a preparation method thereof and an application thereof. Background Art

[0002] Chalcogen lubricant materials are widely used in various mechanical moving components in a vacuum environment, which can reduce the wear between mating materials, reduce the generation of wear debris, and at the same time reduce energy consumption. However, due to the chalcogen solid materials, especially molybdenum disulfide, tungsten disulfide, etc. which are widely used as solid lubricating films, due to their own crystal structure characteristics, the "edge surfaces" in their crystal structures have strong activity and can react with water vapor, oxygen, etc. in the atmospheric environment, destroying the composition and structure of molybdenum disulfide, resulting in a sharp decline in its lubrication performance and failure phenomenon occurring in a short time. Therefore, improving the moisture resistance of chalcogen solid lubricating film materials is a hot topic in the current friction field.

[0003] At present, the common methods for improving the moisture resistance of chalcogen solid lubricating film materials are to improve the film density and dope metal elements (such as noble metals, titanium, lead, etc.). However, the wear life of the materials is short, which limits the application of such films 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 the present invention is to provide a chalcogen composite film, a preparation method thereof and an application thereof. The chalcogen composite film provided by the present invention has a low friction coefficient and a long wear resistance life in a humid environment.

[0005] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a chalcogen composite film, which includes a transition metal chalcogenide and a dopant doped in the transition metal chalcogenide; the dopant includes a doped metal, and the doped metal includes tin, bismuth or a tin-bismuth alloy.

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

[0008] Preferably, the transition metal chalcogenide includes a transition metal and a chalcogen element;

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

[0010] The chalcogen element includes at least one of sulfur and selenium.

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

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

[0013] The present invention also provides a method for preparing the dichalcogenide composite film described in the above technical solution, including the following steps: using a transition metal dichalcogenide and a doped metal as targets, and performing sputtering to obtain the dichalcogenide composite film; the atmosphere of the sputtering includes an inert gas.

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

[0015] The air pressure ratio of nitrogen in the sputtering atmosphere is 0.1-20%.

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

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

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

[0019] The present invention provides a dichalcogenide composite film, including a transition metal dichalcogenide and a dopant doped in the transition metal dichalcogenide; the dopant includes a doped metal, and the doped metal includes tin, bismuth or a tin-bismuth alloy. By doping tin, bismuth or a tin-bismuth alloy in the transition metal dichalcogenide, the present invention can further improve the moisture-resistant environment performance of the dichalcogenide film. The dichalcogenide composite film has a low friction coefficient and a long wear resistance life in a humid environment, and has good application prospects in various environments such as storage, running-in, and normal operation of mechanical moving parts as a solid lubricant material.

[0020] The present invention prepares the dichalcogenide composite film by a sputtering method. The preparation method is simple and effective, low in cost, green and environmentally friendly, and suitable for industrial production. Description of the Drawings

[0021] Figure 1 It is a typical friction curve 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 The typical friction curve of the tungsten disulfide-based composite film obtained in Example 2;

[0024] Figure 4 The typical friction curve of the molybdenum disulfide-based composite film obtained in Example 3;

[0025] Figure 5 The typical friction curve 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 typical friction curve of the molybdenum disulfide film obtained in Comparative Example 1. Detailed implementation mode

[0028] The present invention provides a chalcogen composite film, which includes a transition metal chalcogenide and a dopant doped in the transition metal chalcogenide; the dopant includes a doped metal, and the doped metal includes tin, bismuth or a tin-bismuth alloy.

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

[0030] In the present invention, the mass content of the doped metal in the chalcogen composite film is preferably 0.5-20%, 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 the present invention, the mass ratio of tin to bismuth in the tin-bismuth alloy is preferably 1:0.2-4, 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 the present invention, the dopant preferably further includes nitrogen element. When nitrogen element is contained, the chemical composition of the chalcogen composite film is SnBi / N / MS 2 , where, MS 2is a transition metal dichalcogenide; the mass content of nitrogen element 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 the present invention, nitrogen element can improve the hardness of the dichalcogenide composite film, but if the doping amount of nitrogen element is too large, it will cause the friction coefficient of the dichalcogenide composite film to increase and the wear life to decrease. The present invention controls the mass content of nitrogen in the dichalcogenide composite film below 2%, so that the dichalcogenide composite film can have both high hardness and low friction coefficient.

[0032] In the present invention, the thickness of the dichalcogenide 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 preparation method of the dichalcogenide composite film described in the above technical solution, including the following steps: using a transition metal dichalcogenide and a doped metal as targets, and performing sputtering to obtain the dichalcogenide composite film; the atmosphere of the sputtering includes an inert gas.

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

[0035] In the present invention, the sputtering preferably includes DC sputtering, DC magnetron sputtering, RF sputtering, RF magnetron sputtering or medium frequency magnetron sputtering. In the present invention, during the sputtering process, the transition metal dichalcogenide and the doped metal form the dichalcogenide composite film on the target on the substrate. The present invention has no special limitation on the type of the substrate, and a substrate well-known to those skilled in the art can be used.

[0036] In the present invention, the atmosphere of the sputtering includes an inert gas, and the inert gas preferably includes argon or helium. In the present invention, the atmosphere of the sputtering preferably further includes nitrogen; the pressure ratio of nitrogen in the atmosphere of the sputtering is preferably 0.1-20%, and in specific embodiments, it 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 the present invention, the nitrogen in the dopant comes from the nitrogen in the atmosphere of the sputtering.

[0037] The present invention preferably first pumps the vacuum chamber to a base vacuum and then introduces the atmosphere of the sputtering. In the present invention, the vacuum degree of the base vacuum is preferably 5×10 -4 ~8×10 -3 Pa, and in specific embodiments, it can be 5×10 -4 Pa, 1×10 -3Pa, 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 the present invention, the sputtering gas pressure is preferably 0.2 - 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 - 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 the present invention, the application mode using transition metal dichalcogenide and doped metal as the target is a dual - target independent mode. In the present invention, when the dual - target independent mode is adopted, during the sputtering process, the sputtering power density of the transition metal chalcogenide target is preferably 2 - 160 kW / m 2 , and in specific embodiments, it can be 2 kW / m 2 , 4 kW / m 2 , 5 kW / m 2 , 10 kW / m 2 , 12 kW / m 2 , 20 kW / m 2 , 30 kW / m 2 , 40 kW / m 2 , 50 kW / m 2 , 60 kW / m 2 , 70 kW / m 2 , 80 kW / m 2 , 90 kW / m 2 , 100 kW / m 2 , 110 kW / m 2 , 120 kW / m 2 , 130 kW / m 2 , 140 kW / m 2 , 150 kW / m 2 or 160 kW / m 2 ; the sputtering power density of the doped metal target is preferably 1 - 40 kW / m 2 , and in specific embodiments, it can be 1 kW / m 2 , 2 kW / m 2 , 3 kW / m 2 , 4 kW / m 2 , 5 kW / m 2, 6 kW / m 2 , 7 kW / m 2 , 8 kW / m 2 , 9 kW / m 2 , 10 kW / m 2 , 15 kW / m 2 or 20 kW / m 2 .

[0040] The present invention has no special limitation on the sputtering time, and it can be selected and adjusted according to the required thickness of the chalcogenide composite film.

[0041] The present invention also provides an application of the chalcogenide composite film described in the above technical solution or the chalcogenide composite film prepared by the preparation method described in the above technical solution in mechanical moving parts or vacuum anti-cold welding materials. In the present invention, the chalcogenide composite film is preferably used as a solid lubricant material in one or more of anti-cold welding, lubrication, storage, running-in and transportation of mechanical moving parts. The chalcogenide composite film provided by the present invention has good application prospects in diverse environments such as storage, running-in and transportation of mechanical moving parts, especially in humid atmospheric environments.

[0042] In order to further illustrate the present invention, the chalcogenide composite film provided by the present invention, its preparation method and application will be described in detail below in conjunction with embodiments, but they cannot be understood as limiting the protection scope of the present invention.

[0043] Example 1

[0044] Taking molybdenum disulfide target and tin-bismuth alloy target (mass ratio of tin to bismuth = 1:2.5) as independent targets, the vacuum chamber was pumped to a background vacuum of 5.0×10 -3 Pa, then argon was introduced, the air pressure was adjusted to 4.0 Pa, and by using the radio frequency sputtering method, the sputtering power density of the molybdenum disulfide target was 4 W / cm 2 , the sputtering power density of the tin-bismuth alloy target was 1 W / cm 2 , the sputtering bias voltage was 50 V, and the sputtering time was 30 min. A molybdenum disulfide-based composite film with a thickness of 3.2 μm was obtained on the surface of a polished steel sheet, and the mass percentage content of tin-bismuth was 1.6%.

[0045] The tribological properties of the molybdenum disulfide composite film in a humid atmospheric environment of 45% RH were tested by using a vacuum ball-on-disk tester. The experimental conditions were: a normal load of 5 N and a sliding speed of 1000 r / min. The test results are shown in Figure 1 . It can be seen that the average friction coefficient of the molybdenum disulfide-based composite film in a humid environment is 0.054, and the wear life can reach 8.0×10 5Rotation indicates that the molybdenum disulfide-based composite film has a low friction coefficient and a long wear life in a humid environment.

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

[0047] Example 2

[0048] Using tungsten disulfide target and tin-bismuth alloy target (mass ratio of tin to bismuth = 1:2) as independent targets, the vacuum chamber was pumped to a background vacuum of 5.0×10 -3 Pa, and then argon was introduced to adjust the gas pressure to 5.0 Pa. Using the radio frequency sputtering method, the sputtering power density of the tungsten disulfide target was 4 W / cm 2 , and the sputtering power density of the gold target was 1 W / cm 2 , the sputtering bias voltage was 20 V, and the sputtering time was 30 min. A tungsten disulfide-based composite film with a thickness of 4.2 μm was obtained on the polished steel sheet surface, and the mass percentage content of tin-bismuth was 1.8%.

[0049] The tribological properties of the tungsten disulfide-based composite film in a vacuum environment were tested using a vacuum ball-disk tribometer. The experimental conditions were: a normal load of 5 N, a sliding speed of 1000 r / min, the upper specimen was a bearing steel ball, and the vacuum was better than 5.0×10 -3 Pa. The test results are shown in Figure 3 , and 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 target and tin-bismuth alloy target (mass ratio of tin to bismuth = 1:2) as independent targets, the vacuum chamber was pumped to a background vacuum of 5.0×10 -3 Pa, and then argon and nitrogen were introduced. The nitrogen gas pressure accounted for 2% of the total gas pressure, and the gas pressure was adjusted to 4.0 Pa. Using the radio frequency sputtering method, the sputtering power density of the molybdenum disulfide target was 4 W / cm 2 , and the sputtering power density of the gold target was 1 W / cm 2 , the sputtering bias voltage was 50 V, and the sputtering time was 30 min. A molybdenum disulfide-based composite film with a thickness of 3.2 μm was obtained on the polished steel sheet surface, where the mass percentage content of the tin-bismuth alloy was 1.6% and the mass percentage content of nitrogen was 0.1%.

[0052] The tribological properties of the molybdenum disulfide composite film were tested in a humid atmosphere of 60% RH using a vacuum ball-disk tribometer. The experimental conditions were: a normal load of 5 N and a sliding speed of 1000 r / min. The test results are shown in Figure 4 , and it can be seen that the friction coefficient of the molybdenum disulfide-based composite film in the humid environment is 0.028, and the wear life can reach 6.5×10 5 revolutions in the atmosphere of 60% RH.

[0053] Example 4

[0054] Using molybdenum disulfide target and tin-bismuth alloy target (mass ratio of tin to bismuth = 1:1) as independent targets, the vacuum chamber was pumped to a background vacuum of 5.0×10 -3 Pa, and then argon and nitrogen were introduced. The nitrogen gas pressure accounted for 2% of the total pressure, and the pressure was adjusted to 4.0 Pa. Using the radio frequency sputtering method, the sputtering power density of the molybdenum disulfide target was 12 W / cm 2 , and the sputtering power density of the tin-bismuth alloy target was 1 W / cm 2 , the sputtering bias voltage was 50 V, and the sputtering time was 30 min. A molybdenum disulfide-based composite film with a thickness of 4.8 μm was obtained on the polished steel sheet surface, and the mass percentage content of the tin-bismuth alloy was 1.5%.

[0055] The tribological properties of the molybdenum disulfide-based composite film were tested in a humid atmosphere of 20% RH using a vacuum ball-disk tribometer. The experimental conditions were: a normal load of 5 N and a sliding speed of 1000 r / min. The results are shown in Figure 5 , and it can be seen that the friction coefficient of the molybdenum disulfide-based composite film is 0.011, and the wear life can reach 8.0×10 5 revolutions in the atmosphere of 20% RH, indicating that the molybdenum disulfide-based composite film has a low friction coefficient and a long wear life in the humid environment.

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

[0057] Comparative Example 1

[0058] Using molybdenum disulfide as the target, the vacuum chamber was pumped to a background vacuum of 5.0×10 -3 Pa, and then argon and nitrogen were introduced. The nitrogen gas pressure accounted for 2% of the total pressure, and the pressure was adjusted to 4.0 Pa. Using the radio frequency sputtering method, the sputtering power density of the molybdenum disulfide target was 8 W / cm 2 , the sputtering bias voltage was 30 V, and the sputtering time was 30 min. A molybdenum disulfide-based composite film with a thickness of 4.2 μm was obtained on the polished steel sheet surface.

[0059] The tribological properties in a humid atmosphere of 40% RH were tested using a vacuum ball-disk tribometer. The experimental conditions were: a normal load of 5 N and a sliding speed of 1000 r / min. The results are shown in Figure 7 , and it can be seen that the friction coefficient of the molybdenum disulfide-based composite film is 0.14 and the number of friction cycles is relatively low, only 5.0×10 4 revolutions.

[0060] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A dichalcogenide composite film, characterized in that: The invention comprises a transition metal dichalcogenide compound and a dopant doped in the transition metal dichalcogenide compound; the dopant comprises a doping metal, and the doping metal comprises tin, bismuth or a tin-bismuth alloy.

2. The dichalcogenide composite film according to claim 1, characterized in that: The mass content of the doped metal in the dichalcogenide composite film is 0.5-20%.

3. The dichalcogenide composite film according to claim 1, characterized in that: The transition metal dichalcogenide comprises a transition metal and a chalcogen element; The transition metal includes at least one of molybdenum, tungsten and niobium; The chalcogen element includes at least one of sulfur and selenium.

4. The dichalcogenide composite film according to claim 1, 2 or 3, characterized in that: The transition metal dichalcogenide includes at least one of molybdenum disulfide, tungsten disulfide and niobium diselenide.

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

6. The method for preparing the dichalcogenide composite thin film according to any one of claims 1 to 5, characterized in that: The following steps are involved: The dichalcogenide composite film is obtained by sputtering with a transition metal dichalcogenide compound and a doped metal as target materials; the sputtering atmosphere includes an inert gas.

7. The preparation method according to claim 6, characterized in that: The sputtering atmosphere also includes nitrogen; The gas pressure of nitrogen in the sputtering atmosphere is 0.1-20%.

8. The preparation method according to claim 6 or 7, characterized in that: The gas pressure of the sputtering is 0.2-10 Pa, and the bias voltage is 0-600V.

9. The preparation method according to claim 6, characterized in that: The application mode of using transition metal dichalcogenide and doped metal as target material is a dual-target independent mode; when the dual-target independent mode is adopted, during the sputtering process, the sputtering power density of the transition metal chalcogenide target material is 2 to 160 kW / m 2 The sputtering power density of doped metal targets is 1-40kW / m 2 .

10. Use of the disulfide composite film according to any one of claims 1 to 5 or the disulfide composite film prepared by the preparation method according to any one of claims 6 to 9 in mechanical moving parts or vacuum cold welding prevention materials.

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