Method for arc-ion source composite deposition of carbon-based low-friction film on fluoroether rubber surface

Abstract

The invention discloses a method for arc-ion source composite deposition of a carbon-based low-friction film on the surface of fluoroether rubber, which comprises the following steps: placing a fluoroether rubber base material in a vacuum chamber, vacuumizing to a preset value, and preparing injection metal, a deposition metal bonding layer and a nitride bearing layer by using arc in sequence; and finally, the silicon-doped carbon film is obtained through magnetic filtering arc and linear ion source deposition.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum coating and rubber sealing, and in particular to a method for arc-ion source composite deposition of a carbon-based low-friction film on the surface of a fluoroether rubber and its application. Background Art

[0002] Fluorinated ether rubber (FKM) is widely used as a sealing material in the aerospace, automotive and chemical industries due to its excellent chemical stability, excellent oil resistance and good sealing performance. However, when fluoroether rubber slides relative to engineering materials (such as ceramics, steel, etc.), it is often accompanied by high friction coefficients and severe wear, which limits its service life and reliability in high-performance applications.

[0003] In order to reduce the wear resistance of fluoroether rubber, researchers use organic modified fluoroether monomers or add graphite and molybdenum disulfide to reduce friction. However, doing so will cause the polymer's elastic toughness to deteriorate and reduce its mechanical properties. Depositing lubricating and wear-resistant films on moving parts is an effective way to solve the wear of metal and polymer surfaces. However, how to achieve high bonding strength on the surface of fluoroether rubber is a difficult problem, which limits the application of lubricating films on the surface of fluoroether rubber. The main reason for the poor bonding strength of the fluoroether rubber surface is that the surface F end groups are saturated, which reduces the surface energy. At the same time, the FC bond energy is high. Ordinary glow plasma cleaning is difficult to break the FC bond, exposing the C dangling bond, and cannot be well chemically bonded with the bonding layer. Summary of the invention

[0004] In view of the problems existing in the above-mentioned background technology, the present invention proposes a method for arc-ion source composite deposition of a carbon-based low-friction film on the surface of a fluoroether rubber, using a magnetic filtered arc as a metal ion source, and under the assistance of high bias voltage, breaking the FC bond to achieve chemical bonding between the metal and C and improve the bonding strength.

[0005] 1. Preparation of carbon-based low-friction films 1) Place the fluoroether rubber substrate in a vacuum chamber and evacuate to 4×10 -3 Pa; a Si target for magnetron sputtering, a Ti target for vacuum cathode arc ion plating, and an anode layer linear ion source are installed in the vacuum chamber, and a curved magnetic filter tube is connected between the Ti target for vacuum cathode arc ion plating and the vacuum chamber; Among them, the Si target for magnetron sputtering and the Ti target for vacuum cathode arc ion plating are arranged opposite to each other; the coil current close to the Ti target on the curved magnetic filter tube is 10~15A, the central magnetic field strength is 70~80Gs, the coil current close to the vacuum chamber is 15~20A, and the central magnetic field strength is 110~130Gs; 2) First inject metal Ti, Ti target current 55~65A, bias 900~950V, argon flow 100~110sccm, substrate rotation speed 3~4r / min, injection time 30~40min; 3) Turn on the Si target, adjust the Ti target current to 110~120A, the Si target current to 90~100A, the deposition bias to 70~80V, keep other conditions unchanged, and deposit for 15~25min; each time the fluoroether rubber substrate passes over the Ti target, 4~5nm of metal is deposited, and each time it passes over the Si target, 1~2nm of metal is deposited, forming a TiSi co-deposited metal layer; 4) Keeping other conditions unchanged, introduce nitrogen at 100-110 sccm, bias voltage at 45-55V, and deposit for 60-75min; the fluoroether rubber substrate deposits 2-3 nm of metal each time it passes over the Ti target and 1-2 nm of metal each time it passes over the Si target, forming a TiSiN co-deposited nitride layer; 5) Turn off the Ti target, adjust the Si target current to 75~85A, the anode layer linear ion source: voltage 900~1100V, current 3~5A, duty cycle 80%; turn off the nitrogen, pass acetylene 200 sccm, and deposit for 90~100 minutes.

[0006] 2. Structural Characterization and Performance Evaluation of Carbon-based Low-friction Films 1. Structural characterization The Raman structure of the carbon-based low-friction film is as follows Figure 2 As shown. Figure 2 It can be seen that the Raman spectrum shows two characteristic peaks of carbon film materials: D peak and G peak. The D peak is located at about 1350 cm -1 , which is related to defects or disordered structures in carbon materials, while the G peak is located at about 1580 cm -1 , which is related to the degree of graphitization or ordered sp2 hybridized carbon atoms in the carbon material. The existence of these two peaks indicates that the carbon film has graphitization characteristics and there are certain defects or disordered structures. Overall, this Raman spectrum shows that the carbon film has good graphitization characteristics.

[0007] 2. Performance evaluation The microhardness and elastic modulus of the film were measured by continuous indentation method using a nanoindenter, and the maximum indentation depth was set to 150 nm (to ensure that the indentation depth of the indenter during the test was less than 1 / 10 of the film thickness to avoid the influence of the substrate on the hardness test). At the same time, in order to reduce the measurement error, 5 points were selected for each sample during the test, and the average value was taken as the final result of the experiment, such as Figure 3 The measured hardness of the co-doped carbon film is about 8 GPa, and the elastic modulus is between 64.93 and 75.39 GPa.

[0008] The bonding strength and wear resistance of the film were measured using a scratch tester, using a diamond indenter and a linear variable load mode, with a scratch test distance of 5 mm and a maximum load of 80 N. The bonding strength of the carbon-based low-friction film is as follows: Figure 4 As shown in the figure, it can be seen that with the increase of bonding force, both friction force and friction coefficient show an upward trend, which indicates that carbon-based films have better friction performance under higher bonding force. This performance improvement may be related to the structural stability and improved surface properties of carbon-based films under high bonding force, which may form a more uniform surface or a more effective lubrication layer.

[0009] The friction and wear properties of rubber coated with metal micro-doped carbon film and uncoated rubber in dry atmospheric environment were measured using a ball-disc friction machine. The selected friction load was 10N, the rotation speed was 600r / min, the friction pair was a Φ6mm 440c stainless steel ball, and the rotation radius was 4mm; the friction coefficient curve is as follows Figure 5 shown.

[0010] pass Figure 5 It can be seen that the friction coefficient of the obtained metal micro-doped carbon film is stable between 0.23 and 0.35. Compared with the friction coefficient of fluoroether rubber without carbon film fluctuating around 1.25, the lubrication performance and wear resistance of the metal co-doped carbon film are significantly improved.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. Bonding strength between film and substrate Through the vacuum cathode arc ion plating technology and the optimized design of the curved magnetic filter tube, the present invention can effectively remove the particles attached to the metal ions and improve the purity of the deposited film. At the same time, the injected metal Ti significantly enhances the interface bonding force between the film and the fluoroether rubber substrate, solving the peeling problem of the traditional carbon-based film on the flexible substrate.

[0012] 2. The optimized multilayer structure enhances the comprehensive performance of the film During the film preparation process, by controlling the deposition parameters of the Ti arc target and the Si target, a multilayer structure with alternating distribution of nanoscale metals and nitrides was formed; this structure not only evenly dispersed the residual stress of the film, but also significantly improved the toughness and wear resistance of the film, enabling it to exhibit excellent fatigue resistance under complex working conditions.

[0013] 3. Low temperature deposition process suitable for flexible substrates By regulating deposition conditions (such as bias voltage, gas flow rate and target current), the present invention completes thin film deposition under low temperature conditions without damaging the fluoroether rubber substrate, ensuring the flexibility and integrity of the substrate, which is difficult to achieve in traditional high-temperature coating processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the structure of the carbon-based low-friction film prepared by the present invention.

[0015] Figure 2 This is a Raman spectrum of the carbon-based low-friction film prepared in the present invention.

[0016] Figure 3 The hardness and elastic modulus curves of the carbon-based low-friction film prepared in the present invention.

[0017] Figure 4 The bonding strength and wear resistance curve of the carbon-based low-friction film prepared by the present invention.

[0018] Figure 5 This is the friction coefficient curve of the carbon-based low-friction film prepared in the present invention. DETAILED DESCRIPTION

[0019] The present invention is further explained below with reference to specific embodiments.

[0020] Example 1 1) First place the fluoroether rubber substrate in a vacuum chamber and evacuate to 4×10 -3 Pa; a Si target for magnetron sputtering, a Ti target for vacuum cathode arc ion plating, and an anode layer linear ion source are installed in the vacuum chamber, and a 121° curved magnetic filter tube is connected between the Ti target for vacuum cathode arc ion plating and the vacuum chamber; 2) First, metal Ti was injected, with a Ti target current of 60A, a bias voltage of 930V, an argon flow rate of 100sccm, a substrate rotation speed of 3.5r / min, and an injection time of 30min; 3) Turn on the Si target, adjust the Ti target current to 120A, the Si target current to 100A, the deposition bias to 75V, keep other conditions unchanged, and deposit for 20 minutes; since the Ti and Si targets are placed opposite each other, 5nm of metal is deposited each time the Ti target is scanned, and 2nm of metal is deposited each time the Si target is scanned, forming a TiSi multilayer structure bonding layer; 4) Keeping other conditions unchanged, nitrogen was introduced at 100 sccm, bias voltage was 50V, and deposition was performed for 60 minutes. Since the Ti and Si targets were placed opposite each other, 3 nm of metal was deposited each time the Ti target was scanned, and 1.4 nm of metal was deposited each time the Si target was scanned, forming a TiSiN multilayer structure nitride bearing layer. 5) Turn off the Ti target, adjust the Si target current to 80A, and the anode layer linear ion source: voltage 1100V, current 4A, duty cycle 80%; turn off the nitrogen, introduce 200 sccm of acetylene, and deposit for 90 minutes to form an aC:Si surface layer.

[0021] Structural characterization and performance evaluation are shown above.

Claims

1. A method for arc-ion source composite deposition of carbon-based low-friction film on the surface of fluoroether rubber, characterized in that: The following steps are involved: 1) Place the fluoroether rubber substrate in a vacuum chamber and evacuate to 4×10 -3 Pa; a Si target for magnetron sputtering, a Ti arc target for vacuum cathode arc ion plating, and an anode layer linear ion source are installed in the vacuum chamber, and a curved magnetic filter tube is connected between the Ti target for vacuum cathode arc ion plating and the vacuum chamber; 2) First inject metal Ti, Ti arc target current 55~65A, bias voltage 900~950V, argon flow rate 100~110sccm, substrate rotation speed 3~4r / min, injection time 30~40min; 3) Turn on the Si target, adjust the Ti arc target current to 110~120A, the Si target current to 90~100A, the deposition bias to 70~80V, and keep other conditions unchanged. The deposition time is 15~25min; 4) Keep other conditions unchanged, introduce nitrogen gas at 100-110 sccm, bias voltage at 45-55V, and deposit for 60-75min; 5) Turn off the Ti arc target, adjust the Si target current to 75~85A, the anode layer linear ion source: voltage 900~1100V, current 3~5A, duty cycle 80%; turn off the nitrogen, pass acetylene 200 sccm, and deposit for 90~100 minutes.

2. A method for arc-ion source composite deposition of carbon-based low-friction film on the surface of fluoroether rubber as claimed in claim 1, characterized in that: In step 1), the Si target for magnetron sputtering and the Ti target for vacuum cathode arc ion plating are arranged opposite to each other; the coil current close to the Ti target on the curved magnetic filter tube is 10-15A, the central magnetic field strength is 70-80Gs, and the coil current close to the vacuum chamber is 15-20A, and the central magnetic field strength is 110-130Gs.

3. A method for arc-ion source composite deposition of carbon-based low-friction film on the surface of fluoroether rubber as claimed in claim 1, characterized in that: In step 3), the fluoroether rubber substrate deposits 4 to 5 nm of metal each time it passes over the Ti target and deposits 1 to 2 nm of metal each time it passes over the Si target.

4. A method for arc-ion source composite deposition of carbon-based low-friction film on the surface of fluoroether rubber as claimed in claim 1, characterized in that: In step 4), the fluoroether rubber substrate deposits 2 to 3 nm of metal each time it passes over the Ti target and deposits 1 to 2 nm of metal each time it passes over the Si target.

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