A method for arc-ion source composite deposition of carbon-based low-friction thin films on a fluoroether rubber surface

Abstract

The application discloses a method for depositing a carbon-based low-friction film on a fluoroether rubber surface by using an arc-ion source composite method. The fluoroether rubber base material is placed in a vacuum chamber, vacuumized to a predetermined value, and then metal is introduced by using an arc method, a metal bonding layer is deposited, a nitride bearing layer is deposited, and finally, a silicon-doped carbon film is obtained by using a magnetic filtering arc and a linear ion source.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum coating and rubber sealing, and particularly relates to a fluorine ether rubber surface arc-ion source composite deposition carbon-based low-friction film method and application. BACKGROUND

[0002] Fluoroether rubber (FKM) is widely used as a sealing material in the fields of aerospace, automobile industry and chemical industry due to its excellent chemical stability, excellent oil resistance and good sealing performance. However, when the fluoroether rubber slides against engineering materials (such as ceramics, steel and the like), it is often accompanied by high friction coefficient and serious wear, which limits its service life and reliability in high-performance applications.

[0003] In order to reduce the wear resistance of the fluoroether rubber, researchers use organic modified fluoroether monomers or add graphite and molybdenum disulfide to reduce friction. However, this will cause the polymer to be less flexible and reduce its mechanical properties. Depositing a lubricating wear-resistant film on the moving parts is an effective method to solve the wear of the surface of the metal and polymer. However, how to realize the preparation of high bonding force on the surface of the fluoroether rubber is a difficult problem, which limits the application of the lubricating film on the surface of the fluoroether rubber. The main reason for the poor bonding force on the surface of the fluoroether rubber is that the surface F end group is saturated, which reduces the surface energy, and the F-C bond energy is high, so it is difficult to break the F-C bond by ordinary glow plasma cleaning to expose the C dangling bond, and the C dangling bond cannot be well chemically combined with the adhesive layer. SUMMARY

[0004] In view of the problems in the above background art, the present application provides a method for preparing a carbon-based low-friction film on the surface of a fluoroether rubber. The method uses a magnetic filter arc target as a metal ion source, breaks the F-C bond under the assistance of a high bias, realizes the chemical bonding of metal and C, and improves the bonding force.

[0005] I. Preparation of carbon-based low-friction film

[0006] 1) First, place the fluoroether rubber base material in a vacuum chamber, and vacuumize to 4x10 -3 Pa; the vacuum chamber is provided with a Si target for magnetron sputtering, a Ti arc target for vacuum cathode arc ion plating, and an anode layer linear ion source. The Ti arc target for vacuum cathode arc ion plating is connected with a curved magnetic filter tube between the vacuum chamber;

[0007] The Si target for magnetron sputtering and the Ti arc target for vacuum cathode arc ion plating are oppositely arranged; the coil current on the curved magnetic filter tube close to the Ti arc target for vacuum cathode arc ion plating is 10-15 A, the central magnetic field strength is 70-80 Gs, and the coil current close to the vacuum chamber is 15-20 A, and the central magnetic field strength is 110-130 Gs;

[0008] 2) First, implant metallic Ti. For vacuum cathode arc ion plating, the Ti arc target current is 55~65A, the bias voltage is 900~950V, the argon flow rate is 100~110sccm, the substrate rotation speed is 3~4r / min, and the implantation time is 30~40min.

[0009] 3) Turn on the Si target for magnetron sputtering, adjust the target current of the Ti arc target for vacuum cathode arc ion plating to 110~120A, the current of the Si target for magnetron sputtering to 90~100A, the deposition bias voltage to 70~80V, keep other conditions unchanged, and the deposition time to 15~25min; each time the fluoroether rubber substrate is swept across the Ti arc target for vacuum cathode arc ion plating, 4~5nm of metal is deposited, and each time it is swept across the Si target for magnetron sputtering, 1~2nm of metal is deposited, forming a TiSi co-deposited metal layer;

[0010] 4) Keeping other conditions unchanged, nitrogen gas is introduced at 100~110 sccm, bias voltage is 45~55V, and deposition is carried out for 60~75min; the fluoroether rubber substrate is swept through the vacuum cathode arc ion plating Ti arc target to deposit 2~3 nm of metal each time, and swept through the magnetron sputtering Si target to deposit 1~2 nm, forming a TiSiN co-deposited nitride layer.

[0011] 5) Turn off the Ti arc target for vacuum cathode arc ion plating and adjust the current of the Si target for magnetron sputtering to 75~85A; turn on the linear ion source for the anode layer and control the parameters as follows: voltage 900~1100V, current 3~5A, duty cycle 80%; turn off the nitrogen gas, introduce 200 sccm of acetylene, and deposit for 90~100min.

[0012] II. Structural Characterization and Performance Evaluation of Carbon-Based Low-Friction Thin Films

[0013] 1. Structural characterization

[0014] The Raman structure of the carbon-based low-friction thin film is as follows: Figure 2 As shown. By Figure 2 As can be seen, the Raman spectrum reveals two characteristic peaks of the carbon film material: the D peak and the G peak. The D peak is located at approximately 1350 cm⁻¹. -1 This is related to defects or disordered structures in carbon materials, while the G peak is located at approximately 1580 cm⁻¹. -1 The presence of these two peaks is related to the degree of graphitization or the ordered sp2 hybridization of carbon atoms in the carbon material. The presence of these two peaks indicates that the carbon film possesses graphitization characteristics, while also exhibiting certain defects or a disordered structure. Overall, this Raman spectrum demonstrates that the carbon film exhibits good graphitization properties.

[0015] 2. Performance Evaluation

[0016] The microhardness and elastic modulus of the thin film were measured by continuous indentation method using a nanoindenter. The maximum indentation depth was set to 150 nm (to ensure that the indentation depth of the indenter was less than 1 / 10 of the thickness of the thin film during the test, so as to avoid the influence of the substrate on the hardness test); in order to reduce the measurement error, 5 points of each sample were selected for measurement during the test, and the average value was taken as the final result of the experiment, as shown in Figure 3 The measured hardness of the co-doped carbon thin film was about 8 GPa, and the elastic modulus was between 64.93 and 75.39 GPa.

[0017] The adhesion and wear resistance of the thin film were measured using a scratch tester. A diamond indenter and a linear variable load mode were used, the scratch test distance was 5 mm, and the maximum load was 80 N. The adhesion of the carbon-based low-friction thin film was as follows Figure 4 As can be seen from the figure, with the increase of the adhesion, the friction force and the friction coefficient both show an upward trend, which indicates that the carbon-based thin film has better friction performance under higher adhesion. The improvement of this performance may be related to the stability of the structure and the improvement of the surface properties of the carbon-based thin film under high adhesion, which may form a more uniform surface or a more effective lubricating layer.

[0018] The friction and wear properties of the rubber coated with metal micro-doped carbon thin film and the rubber without coating were measured in a dry atmospheric environment using a ball-on-disc friction machine. The selected friction load was 10 N, the rotation speed was 600 r / min, the friction pair was a Φ6 mm 440c stainless steel ball, and the rotation radius was 4 mm. The friction coefficient curve is as follows Figure 5 .

[0019] It can be seen from Figure 5 that the friction coefficient of the metal micro-doped carbon thin film is stable at 0.23~0.35, and compared with the friction coefficient of the fluorine ether rubber without carbon film, which fluctuates around 1.25, the lubrication performance and wear resistance of the metal co-doped carbon thin film are significantly improved.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] 1. The adhesion of the thin film to the substrate

[0022] Through the optimization design of the vacuum cathode arc ion plating technology and the curved magnetic filter tube, the present application can effectively remove the particles attached to the metal ions, and improve the purity of the deposited thin film. At the same time, the injected metal Ti significantly enhances the interfacial adhesion between the thin film and the fluorine ether rubber substrate, solving the peeling problem of traditional carbon-based thin films on flexible substrates.

[0023] 2. The optimized multi-layer structure enhances the comprehensive performance of the thin film

[0024] In the thin film preparation process, by controlling the deposition parameters of Ti arc target and Si target, a multilayer structure of nanoscale metal and nitride alternately distributed is formed; the structure not only uniformly disperses the residual stress of the thin film, but also significantly improves the toughness and wear resistance of the thin film, so that the thin film exhibits excellent fatigue resistance under complex working conditions.

[0025] 3. Low temperature deposition process suitable for flexible substrate

[0026] By adjusting the deposition conditions (such as bias voltage, gas flow and target current), the thin film deposition is completed at a low temperature without damaging the fluoroether rubber substrate, ensuring the flexibility and integrity of the substrate, which is difficult to achieve in traditional high-temperature coating process. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 Structure diagram of carbon-based low-friction thin film prepared by the present application.

[0028] Figure 2 Raman spectrum of carbon-based low-friction thin film prepared by the present application.

[0029] Figure 3 Hardness and elastic modulus curve of carbon-based low-friction thin film prepared by the present application.

[0030] Figure 4 Adhesion and wear resistance curve of carbon-based low-friction thin film prepared by the present application.

[0031] Figure 5 Friction coefficient curve of carbon-based low-friction thin film prepared by the present application. DETAILED DESCRIPTION

[0032] The present application will be further explained and described below in conjunction with specific embodiments.

[0033] Example 1

[0034] 1) First, place the fluoroether rubber substrate in the vacuum chamber, and vacuumize to 4×10 -3 Pa; the vacuum chamber is provided with a Si target for magnetron sputtering, a Ti arc target for vacuum cathode arc ion plating, and an anode layer linear ion source, and a curved magnetic filter tube with an angle of 121° is connected between the Ti arc target for vacuum cathode arc ion plating and the vacuum chamber.

[0035] 2) First, inject metal Ti, the Ti arc target for vacuum cathode arc ion plating has a current of 60 A, a bias voltage of 930 V, an argon gas flow of 100 sccm, a substrate rotation speed of 3.5 r / min, and an injection time of 30 min;

[0036] 3) Turn on the Si target for magnetron sputtering, adjust the Ti arc target current for vacuum cathode arc ion plating to 120 A, the Si target current for magnetron sputtering to 100 A, the deposition bias to 75 V, and keep other conditions unchanged, and deposit for 20 min; since the Ti and Si targets are placed opposite to each other, 5 nm of metal is deposited each time the Ti arc target for vacuum cathode arc ion plating is swept, and 2 nm is deposited each time the Si target for magnetron sputtering is swept, thereby forming a TiSi multilayer structure adhesion layer;

[0037] 4) Keep other conditions unchanged, introduce nitrogen at a flow rate of 100 sccm, the deposition bias is 50 V, and deposit for 60 min; since the Ti and Si targets are placed opposite to each other, 3 nm of metal is deposited each time the Ti arc target for vacuum cathode arc ion plating is swept, and 1.4 nm is deposited each time the Si target for magnetron sputtering is swept, thereby forming a TiSiN multilayer structure nitride bearing layer;

[0038] 5) Turn off the Ti arc target for vacuum cathode arc ion plating, and adjust the Si target current for magnetron sputtering to 80 A; turn on the anode layer linear ion source, and control the parameters as follows: voltage 1100 V, current 4 A, and duty cycle 80%; turn off the nitrogen, introduce acetylene at a flow rate of 200 sccm, and deposit for 90 min, thereby forming a a-C:Si surface layer.

[0039] The structural characterization and performance evaluation are described above.

Claims

1. A method for depositing a carbon-based low-friction thin film on the surface of fluoroether rubber using an arc-ion source composite deposition method, characterized in that, Includes the following steps: 1) First, place the fluoroether rubber substrate in a vacuum chamber and evacuate it to a vacuum level of 4×10. -3 Pa; The vacuum chamber is equipped with a Si target for magnetron sputtering, a Ti arc target for vacuum cathode arc ion plating, and a linear ion source for the anode layer. A bent magnetic filter tube is connected between the Ti arc target for vacuum cathode arc ion plating and the vacuum chamber. Among them, the Si target for magnetron sputtering and the Ti arc target for vacuum cathode arc ion plating are arranged opposite each other; the coil current on the bent magnetic filter tube near the Ti arc target for vacuum cathode arc ion plating is 10~15A, the central magnetic field strength is 70~80Gs, and the coil current near the vacuum chamber is 15~20A, the central magnetic field strength is 110~130Gs. 2) First, implant metallic Ti. For vacuum cathode arc ion plating, the Ti arc target current is 55~65A, the bias voltage is 900~950V, the argon flow rate is 100~110sccm, the substrate rotation speed is 3~4r / min, and the implantation time is 30~40min. 3) Turn on the Si target for magnetron sputtering, adjust the current of the Ti arc target for vacuum cathode arc ion plating to 110~120A, the current of the Si target for magnetron sputtering to 90~100A, the deposition bias voltage to 70~80V, keep other conditions unchanged, and the deposition time to 15~25min. 4) Keeping other conditions unchanged, introduce nitrogen gas at 100~110 sccm, apply a bias voltage of 45~55V, and deposit for 60~75min; 5) Turn off the Ti arc target for vacuum cathode arc ion plating and adjust the current of the Si target for magnetron sputtering to 75~85A; turn on the linear ion source for the anode layer and control the parameters as follows: voltage 900~1100V, current 3~5A, duty cycle 80%; turn off the nitrogen gas, introduce 200 sccm of acetylene, and deposit for 90~100min.

2. The method for depositing a carbon-based low-friction thin film on the surface of fluoroether rubber using an arc-ion source composite deposition method as described in claim 1, characterized in that, In step 3), the fluoroether rubber substrate is swept across the Ti arc target for vacuum cathode arc ion plating to deposit 4-5 nm of metal each time, and swept across the Si target for magnetron sputtering to deposit 1-2 nm of metal.

3. The method for depositing a carbon-based low-friction thin film on the surface of fluoroether rubber using an arc-ion source composite deposition method as described in claim 1, characterized in that... In step 4), the fluoroether rubber substrate is swept across the Ti arc target for vacuum cathode arc ion plating to deposit 2-3 nm of metal each time, and swept across the Si target for magnetron sputtering to deposit 1-2 nm of metal.

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