A method for preparing Ti / Cr / Cu co-doped composite nitride thin films on the surface of fluoroether rubber

Abstract

The application discloses a preparation method of a fluorine ether rubber surface Ti / Cr / Cu co-doped composite nitride film, wherein the fluorine ether rubber base material is washed, dried, and then placed into a magnetron sputtering cavity; Ar gas is introduced to clean the base after the cavity is pumped to a high vacuum condition; and a modified Ti / Cr / Cu co-doped composite nitride film is obtained by using a cathode arc magnetic filtering technology. The obtained Ti / Cr / Cu co-doped composite nitride film obviously improves the friction performance, and meanwhile, the film itself density and hardness are maintained; the cathode arc magnetic filtering technology makes the doping elements uniformly dispersed in the film, ensures that a small amount of doping elements can improve the film performance, and improves the tribological performance of the film.

Description

Technical Field

[0001] This invention belongs to the field of vacuum coating and rubber sealing technology, and particularly relates to a method for preparing a Ti / Cr / Cu co-doped composite nitride film on the surface of fluoroether rubber. Background Technology

[0002] Fluoropolymer rubber (FKM) is widely used as a sealing material in aerospace, automotive, and chemical industries due to its excellent chemical stability, superior oil resistance, and good sealing performance. However, in practical applications, the relative sliding between the surface of FKM and engineering materials (such as ceramics and steel) often results in a high coefficient of friction and severe wear. This significantly affects its service life and reliability, limiting its application in high-performance fields. To improve the tribological properties of FKM, current research mainly focuses on surface modification techniques, such as depositing hard films (e.g., metal nitride films or diamond-like carbon films). These films, due to their excellent wear resistance and low friction characteristics, can improve the surface properties of FKM to some extent. However, traditional film preparation techniques still have significant shortcomings when applied to the surface of FKM, including weak film adhesion, poor deposition uniformity, and complex preparation processes. In particular, due to the chemical inertness of the FKM surface, the interfacial bonding force between the film and the substrate is low, which easily leads to peeling or failure of the film during use. Furthermore, achieving high-quality, uniformly distributed film deposition on flexible substrates presents significant challenges, while the complexity and high cost of the fabrication process limit its industrial application. Therefore, how to prepare films with high adhesion, good uniformity, and excellent tribological properties on fluoroether rubber surfaces has become a pressing technical problem to be solved in this field. Summary of the Invention

[0003] In view of this, the present invention discloses a method for preparing a Ti / Cr / Cu co-doped composite nitride film on the surface of fluoroether rubber. The modified Ti / Cr / Cu co-doped composite nitride film is obtained by using cathodic arc magnetic filtration technology. This method can effectively improve the adhesion of the film, ensure the uniformity and stability of the film, thereby significantly improving the wear resistance of fluoroether rubber and reducing its coefficient of friction.

[0004] I. Preparation of Ti / Cr / Cu co-doped composite nitride films

[0005] 1) First, ultrasonically clean the fluoroether rubber substrate with alcohol for 10-20 minutes to remove surface contaminants, then dry it and place it on the sample rack in the vacuum chamber; evacuate the vacuum until the pressure is less than 5×10⁻⁶. -3After Pa, high-purity argon gas is introduced, and the pressure in the vacuum chamber is controlled at 0.3~0.5Pa. The bias power supply is adjusted to -500~-800V to perform bias cleaning on the substrate surface to remove impurities. The processing time is 10~15min.

[0006] 2) First turn on the Cr target, adjust the Cr arc target current to 80~100A, voltage to 20~25V, argon gas flow rate to 150~250sccm, maintain the gas pressure at 0.40~0.45pa, control the bias voltage at 700±50V, duty cycle to 60~70%, and injection time to 20~40min.

[0007] 3) Deposition of Cr metal layer: Adjust the Cr arc target current to 150~170A, voltage to 30~35V, argon gas flow rate to 100~120sccm, gas pressure to 0.28~0.30pa, deposition bias voltage to 70~80V, duty cycle to 60~70%, and deposition time to 20~40min.

[0008] 4) Deposition of CrN layer: Based on step 3), nitrogen flow rate is introduced at 100~120 sccm, argon flow rate remains unchanged, gas pressure is maintained at 0.35~0.40 Pa, and deposition time continues for 45~60 min;

[0009] 5) Deposition of multilayer metal nitride layers: Turn on the Ti target, control the current ratio and voltage ratio of the Cr / Ti target to be 1:1, keep the flow rates of nitrogen and argon constant, control the bias voltage at 70~80V, and the duty cycle at 60~70%; turn on the central pillar target Cu target, control the current at 1~2A, the voltage at 250~260V, the duty cycle at 60~70%, and the deposition time at 45~60min.

[0010] In the above preparation process, the Cr arc target and the Ti arc target are symmetrically arranged on the left and right sides of the vacuum chamber and connected to the vacuum chamber through a magnetic filter bend. The magnetic field current of the magnetic filter bend connected to the Cr arc target is 70~80A, and the magnetic field current of the magnetic filter bend connected to the Ti arc target is 35~45A. The central pillar target Cu target is located at the center of the vacuum chamber.

[0011] II. Performance Evaluation and Structure of Ti / Cr / Cu Co-doped Composite Nitride Thin Films

[0012] 1. Performance Evaluation

[0013] The microhardness and elastic modulus of the thin film were determined using a nanoindenter via a continuous indentation method. The maximum indentation depth was set to 150 nm (to ensure that the indentation depth of the indenter during testing was less than 1 / 10 of the film thickness, thus avoiding the influence of the substrate on the hardness test). To further reduce measurement error, five points were measured for each sample, and the average value was used as the final experimental result.Figure 2 As shown, the measured hardness of the Ti / Cr / Cu co-doped composite nitride film is 32.8 GPa, and the elastic modulus is 349.5 GPa. It exhibits excellent mechanical properties, with extremely high wear resistance and deformation resistance.

[0014] The tribological properties of rubber coated with a Ti / Cr / Cu co-doped composite nitride film and uncoated rubber under dry atmospheric conditions were determined using a ball-disc friction tester. The selected friction load was 3 N, the rotation speed was 600 r / min, and the friction pair consisted of Φ6 mm 440C stainless steel balls with a rotation radius of 4 mm. The friction coefficient curves are shown below. Figure 3 As shown.

[0015] pass Figure 3 It can be seen that the friction coefficient of the Ti / Cr / Cu co-doped composite nitride film is stable between 0.28 and 0.32, while the friction coefficient of the fluoroether rubber without film fluctuates around 1.35. The lubrication performance and wear resistance of the Ti / Cr / Cu co-doped composite nitride film are significantly improved.

[0016] 2. Structure of Ti / Cr / Cu co-doped composite nitride films

[0017] Figure 4 The image shows the surface morphology of the Ti / Cr / Cu co-doped composite nitride film prepared by the cathode arc magnetic filtration technology of this invention. The surface morphology of the co-doped film can be seen intuitively. The film is relatively uniformly distributed on the substrate surface, and the particle size and distribution in the film are relatively consistent. This means that the film has a moderate thickness and good density, and the adhesion between the film and the substrate is good.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] By employing cathode arc magnetic filtration technology, this invention effectively removes particles attached to metal ions, improving the purity of the deposited film. It ensures that doping elements are uniformly dispersed within the film, guaranteeing performance enhancement even with minimal doping. The use of a combination of soft and hard metals within the film significantly strengthens the interfacial bonding between the film and the fluoroether rubber substrate, resolving the peeling problem of traditional nitride films on flexible substrates. During friction, the orderliness of the friction interface is significantly improved, resulting in a low coefficient of friction and low wear rate, thus enhancing the film's tribological properties. This special Ti / Cr / Cu co-doped composite nitride film significantly improves the deposition quality of nitride films. The method is simple, cost-effective, and provides guidance for industrial production. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the structure of the Ti / Cr / Cu co-doped composite nitride film prepared in this invention.

[0021] Figure 2 The hardness and elastic modulus curves of the Ti / Cr / Cu co-doped composite nitride film prepared for this invention.

[0022] Figure 3 The friction coefficient curve of the Ti / Cr / Cu co-doped composite nitride film prepared in this invention.

[0023] Figure 4 This is a 300 μm scanning electron microscope image of the Ti / Cr / Cu co-doped composite nitride film prepared in this invention. Detailed Implementation

[0024] The present invention will be further explained and described below with reference to specific embodiments. Example

[0025] See Figure 1 The Ti / Cr / Cu co-doped composite nitride thin film of the present invention, as shown in the figure, is prepared as follows:

[0026] 1) First, ultrasonically clean the fluoroether rubber substrate with alcohol for 10-20 minutes to remove surface contaminants, then dry it and place it on the sample rack in the vacuum chamber; evacuate the vacuum until the pressure is less than 5×10⁻⁶. -3 After Pa, high-purity argon gas is introduced, and the pressure in the vacuum chamber is controlled at 0.3~0.5Pa. The bias power supply is adjusted to -500~-800V to perform bias cleaning on the substrate surface to remove impurities. The processing time is 10~15min.

[0027] 2) First turn on the Cr target, adjust the Cr arc target current to 100A and voltage to 23V, introduce argon gas flow rate to 200sccm, maintain the gas pressure at 0.40~0.45pa, control the bias voltage at 700V, the duty cycle at 60%, and the injection time at 30min.

[0028] 3) Deposition of Cr metal layer: Adjust the Cr arc target current to 160A and voltage to 31V, reduce the argon gas flow rate to 100sccm, the gas pressure to 0.28~0.30pa, control the deposition bias voltage at 75V, the duty cycle at 60%, and the deposition time to 30min.

[0029] 4) Deposition of CrN layer: Keep the Cr arc target current constant, adjust the voltage to 33V, the nitrogen flow rate to 100sccm, the argon flow rate constant (100sccm), the gas pressure to 0.36pa, control the bias voltage to 75V, the duty cycle to 60%, and the deposition time to 60min.

[0030] 5) Deposition of multilayer metal nitride layers: Turn on the Ti target, adjust the current of the two arc targets, control the Cr / Ti current ratio to 160A / 160A and the voltage ratio to 35V / 35V, keep the nitrogen and argon flow rates constant (100sccm), control the bias voltage to 75V and the duty cycle to 60%, turn on the central pillar target Cu target, control the current to 1A, the voltage to 252V, the duty cycle to 60%, and the deposition time to 60min.

[0031] Structural characterization and performance evaluation are described above.

Claims

1. A method for preparing fluorine ether rubber surface Ti / Cr / Cu co-doped composite nitride film, characterized in that, The composite nitride film comprises a Cr metal bearing layer, a CrN intermediate transition layer and a Ti / Cr / Cu metal nitride surface friction-reducing layer deposited on the surface of the fluoroether rubber, and the preparation steps are as follows: 1) First, fluoroether rubber base material is cleaned with alcohol for 10-20 min by ultrasonic to remove surface contaminants, and then dried and placed on the sample holder in the vacuum chamber; vacuum to less than 5x10 -3 Pa, then introduce high-purity argon, control the pressure in the vacuum chamber to 0.3-0.5 Pa, adjust the bias voltage to -500 to -800 V, and perform bias cleaning on the surface of the base material to remove impurities on the surface of the base material, and the processing time is 10-15 min; 2) first open the Cr target, adjust the Cr arc target current to 80-100 A, the voltage to 20-25 V, the argon gas flow to 150-250 sccm, the gas pressure to 0.40-0.45 pa, the bias voltage to 700±50 V, the duty cycle to 60-70%, and the injection time to 20-40 min; 3) deposit the Cr metal layer: adjust the Cr arc target current to 150-170 A, the voltage to 30-35 V, the argon gas flow to 100-120 sccm, the gas pressure to 0.28-0.30 pa, the deposition bias voltage to 70-80 V, the duty cycle to 60-70%, and the deposition time to 20-40 min; 4) deposit the CrN layer: on the basis of step 3), the nitrogen gas flow is 100-120 sccm, the argon gas flow remains unchanged, the gas pressure is maintained at 0.35-0.40 pa, and the deposition time is continued for 45-60 min; 5) deposit the multi-layer metal nitride layer: open the Ti target, control the Cr / Ti current ratio and voltage ratio to be 1:1, keep the nitrogen and argon gas flows unchanged, control the bias voltage to be 70-80 V, and the duty cycle to be 60-70%; open the center column target Cu target, control the current to be 1-2 A, the voltage to be 250-260 V, the duty cycle to be 60-70%, and the deposition time to be 45-60 min.

2. The method for preparing a Ti / Cr / Cu co-doped composite nitride film on a fluoroether rubber surface as described in claim 1, characterized in that, The following steps are included: 1) First, the fluoroether rubber base material is ultrasonically cleaned with alcohol for 10-20 min to remove surface contaminants, and after drying, it is placed on the sample holder in the vacuum chamber; vacuum is drawn to a pressure of less than 5 x 10 -3 Pa, high-purity argon gas is introduced, the pressure in the vacuum chamber is controlled to be 0.3-0.5 Pa, the bias voltage source is adjusted to -500 to -800 V, the surface of the base material is bias cleaned to remove impurities on the surface of the base material, and the treatment time is 10-15 min; 2) first open the Cr target, adjust the Cr arc target current to 100 A, the voltage to 23 V, the argon gas flow to 200 sccm, maintain the gas pressure to 0.40-0.45 pa, control the bias voltage to 700 V, the duty cycle to 60%, and the injection time to 30 min; 3) deposit the Cr metal layer: adjust the Cr arc target current to 160 A, the voltage to 31 V, reduce the argon gas flow to 100 sccm, the gas pressure to 0.28-0.30 pa, control the deposition bias voltage to 75 V, the duty cycle to 60%, and the deposition time to 30 min; 4) deposit the CrN layer: keep the Cr arc target current unchanged, adjust the voltage to 33 V, the nitrogen gas flow to 100 sccm, the argon gas flow to continue to be 100 sccm, the gas pressure to 0.36 pa, control the bias voltage to 75 V, the duty cycle to 60%, and the deposition time to 60 min; 5) deposit the multi-layer metal nitride layer: open the Ti target, adjust the two arc target currents, control the Cr / Ti current ratio to be 160 A / 160 A, the voltage ratio to be 35 V / 35 V, maintain the nitrogen and argon gas flows to be 100 sccm each, control the bias voltage to be 75 V, the duty cycle to be 60%, open the center column target Cu target, control the current to be 1 A, the voltage to be 252 V, the duty cycle to be 60%, and the deposition time to be 60 min.

3. The method for preparing a Ti / Cr / Cu co-doped composite nitride film on a fluoroether rubber surface as described in claim 2, characterized in that, In step 5), the Cr arc target and the Ti arc target are symmetrically arranged on the left and right sides of the vacuum chamber and connected with the vacuum chamber through the magnetic filtering elbow, the magnetic field current of the magnetic filtering elbow connected with the Cr arc target is 70-80 A, the magnetic field current of the magnetic filtering elbow connected with the Ti arc target is 35-45 A, and the center column target Cu target is located in the center of the vacuum chamber.

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