A method for preparing a rubber surface TiCr / Cu multilayer composite film

Abstract

The application discloses a preparation method of a rubber surface TiCr / Cu multilayer composite film. A Ti metal adhesive layer is first deposited on the surface of a rubber base by using a magnetic filter cathode arc deposition technology, and then a TiCr gradient mixed layer, a TiCrCu gradient bearing layer and a surface layer composed of TiCr layers and Cu layers are sequentially deposited by using a high-power pulse magnetron sputtering technology. The obtained TiCr / Cu multilayer composite film has a friction coefficient of about 0.3, which is reduced from 1.3 of bare rubber.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a rubber surface TiCr / Cu multilayer composite film and belongs to the field of solid lubricating materials and tribology. BACKGROUND

[0002] There are a large number of rubber sealing devices in modern industrial equipment to prevent leakage of working medium and invasion of dust and foreign matters from the outside. Once the sealing medium leaks, it will directly endanger personal safety and cause huge economic losses. At present, most sealing leakage accidents are related to the sealing failure of sealing parts. Therefore, the sealing failure of sealing parts is one of the key common technical problems of mechanical equipment sealing systems. When rubber and metal pairs are used, the friction coefficient is extremely high (µ>1), and the friction heat generated by high friction easily leads to the softening and rapid wear failure of rubber sealing parts, so that the high-pressure sealing medium leaks from the damaged part and the sealing fails, affecting the safe and reliable service of the equipment. Therefore, to solve the problem of wear failure of rubber sealing parts, we must start from reducing friction.

[0003] Patent CN201810736543.8 proposes a preparation method of graphene modified fluoroether rubber, which adopts in-situ growth of flaky graphene needle-shaped zinc oxide micro-nano composite, and the needle-shaped oxide in the composite is inserted into the graphene sheet to inhibit the aggregation between the components. Through the synergy of multiple components, the friction and wear and heat conduction performance are significantly improved, while the mechanical strength is maintained. However, the rubber obtained by this method is affected by the quality of graphene itself, and the production line needs to be greatly improved, which is too high in cost. Patent CN 201811485726.3 discloses a preparation method of a polymer-like carbon film applied to the surface of fluorine rubber for wear resistance and friction reduction modification and fluorine rubber prepared by using the carbon film, which comprises: taking fluorine rubber as a base material and performing sputtering cleaning on the base; using a medium frequency magnetron sputtering deposition technology to perform bombardment sputtering on a graphite target material to generate a mixed plasma; while sputtering the target material, a medium frequency pulse direct current bias power supply is turned on to accelerate the mixed plasma to reach the base material and deposit on the fluorine rubber base material. However, this method does not well solve the problems of high hardness and poor performance of the carbon film, and the carbon film falls off after long-term placement. Patent CN202110538435 provides a preparation method of an ultra-high wear-resistant rubber-based composite material with a continuous structure surface carbon film, which is to perform micro-nano texturing on a rubber base after pre-cleaning, then perform bombardment cleaning and activation treatment on the micro-nano textured rubber base by nitrogen plasma and argon plasma in sequence, and then deposit a carbon film on the surface of the rubber base to obtain an ultra-high wear-resistant rubber-based composite material with a continuous structure. This method of constructing micro-nano texture can effectively reduce the internal stress of the carbon film and improve the bonding force and service life of the carbon film, but it is challenging to control the preparation of the texture and realize batch production.

[0004] The application takes into account the hard and brittle problem of carbon film, and benefits from the good flexibility of TiCr / Cu film and the lubricity of copper, and proposes a preparation method of rubber surface TiCr / Cu multilayer composite film. SUMMARY

[0005] The application discloses a preparation method of rubber surface TiCr / Cu multilayer composite film, to solve the problems of hard and brittle carbon film, easy to fall off and difficult to be applied in engineering in the prior art.

[0006] I. Preparation of rubber surface TiCr / Cu multilayer composite film

[0007] The preparation method of the rubber surface TiCr / Cu multilayer composite film disclosed by the application first deposits a Ti metal adhesive layer (A) on the surface of a rubber substrate by using a magnetic filter cathode arc deposition technology, then sequentially deposits a TiCr gradient mixed layer (M), a TiCrCu gradient bearing layer (TC2) and a surface layer composed of TiCr layers (TC1) and Cu (C) layers by using a high-power pulse magnetron sputtering technology, and the specific process is as follows:

[0008] 1) First, fix the cleaned rubber substrate in a vacuum chamber, and vacuumize to 2x10 -4 Pa; the vacuum chamber is provided with a Cu target and a Cr target for magnetron sputtering, a curved magnetic filter tube is connected between the Cu target and the Cr target, and a Ti arc target for magnetic filter cathode arc deposition is fixed at the other end of the curved magnetic filter tube; the rubber substrate is one of nitrile rubber, fluorine rubber and silicone rubber;

[0009] 2) Turn on the Ti arc target for magnetic filter cathode arc deposition, set the Ti target current to 75-85 A, the bias voltage to 350-400 V, the Ar gas pressure to 0.3-0.5 Pa, the rubber substrate rotation speed to 1-2 r / min, and the deposition time to 15-20 min; the coil current near the Ti arc target for magnetic filter cathode arc deposition on the 135° magnetic filter elbow is 20-30 A, the central magnetic field strength is 80-90 Gauss, the coil current near the vacuum chamber is 30-40 A, and the central magnetic field strength is 100-110 Gauss;

[0010] 3) Keep the rest unchanged, adjust the Ti arc target current to 120-130 A, and at the same time, gradually increase the Cr target for magnetron sputtering from 0 A to 12 A within 20 min, the bias voltage is 65-75 V, and the deposition time is 20-25 min;

[0011] 4) Keep the rest unchanged, open the Cu target for magnetron sputtering, set the current to 5-10 A, the bias voltage to 65-75 V, and the deposition time to 10-15 min;

[0012] 5) TiCr layer deposition and Cu layer deposition are alternately carried out for 140-160 cycles; when the TiCr layer is deposited, the Cu target for magnetron sputtering is closed, the process parameters of the Ti arc target for magnetic filter cathode arc deposition and the Cr target for magnetron sputtering are kept unchanged, and the TiCr layer is deposited for 5-10 min; when the Cu layer is deposited, the Ti arc target for magnetic filter cathode arc deposition and the Cr target for magnetron sputtering are closed, the process parameters of the Cu target for magnetron sputtering are kept unchanged, and the Cu layer is deposited for 5-10 min.

[0013] Figure 1 A structure diagram of the TiCr / Cu multilayer composite film on the rubber surface of the application, wherein S is a rubber substrate, a Ti metal adhesive layer (A) is first deposited on the surface of the rubber substrate (S) by using the magnetic filter cathode arc deposition technology, then a TiCr gradient mixed layer (M), a TiCrCu gradient bearing layer (TC2) and a surface layer composed of TiCr layers (TC1) and Cu (C) layers are sequentially deposited by using the high-power pulse magnetron sputtering technology, through multilayer regulation, the high hardness of TiCr and the lubricity of Cu are fully utilized, a lubricating layer with high strength and deformation resistance is formed, and good wear resistance and fatigue resistance are obtained.

[0014] II. Performance of the TiCr / Cu multilayer composite film on the rubber surface

[0015] 1. Bonding strength

[0016] The bonding force of the film is 52 N measured by the spherical scratch method.

[0017] 2. Friction performance

[0018] 2.1 Friction performance in a vacuum environment

[0019] The friction coefficient is tested by using a ball-on-disc friction tester, a load of 3 N and a speed of 600-1000 rpm in a vacuum environment (vacuum degree 4x10 -3 Pa), and the data are listed in Table 1. Compared with the friction coefficient (1.26) of the uncoated rubber, the friction coefficient is reduced to about 0.23-0.20.

[0020] 2.2 Friction performance in a dry atmosphere

[0021] The friction coefficient is tested by using a ball-on-disc friction tester, a load of 3 N and a speed of 600-1000 rpm in a dry atmosphere (humidity <10%), and the data are listed in Table 1. Compared with the friction coefficient (1.32) of the uncoated rubber, the friction coefficient is reduced to about 0.25-0.21.

[0022] 2.3 Friction performance in a nitrogen environment

[0023] The friction coefficient was tested by a ball-on-disc tribometer under a load of 3 N and a speed of 600-1000 rpm in a nitrogen environment, and the data are listed in Table 1. The friction coefficient was reduced to about 0.27-0.25, respectively, compared with the friction coefficient (1.29) of the uncoated rubber.

[0024] 2.4 Friction performance in a 3.0% humid air environment

[0025] The friction coefficient was tested by a ball-on-disc tribometer under a load of 3 N and a speed of 600-1000 rpm in a 3.0% humid air environment, and the data are listed in Table 1. The friction coefficient was reduced to about 0.28-0.25, respectively, compared with the friction coefficient (1.32) of the uncoated rubber.

[0026] Table 1 Friction performance of TiCr / Cu multilayer film on rubber surface

[0027]

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The use of flexible metal film avoids the problem of poor bonding force and poor fatigue resistance caused by high brittleness of carbon film, and the efficiency of depositing metal film is more than 5 times that of carbon film, greatly saving the cost and being conducive to promoting the application of lubricating film in the rubber industry. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 Fig. 1 is a structural schematic diagram of the TiCr / Cu multilayer film on the rubber surface of the present application. DETAILED DESCRIPTION

[0031] The present application will be further described below in conjunction with specific examples. In the present application, the terms used have meanings generally understood by those of ordinary skill in the art unless otherwise specified. In the following examples, various processes and methods not described in detail are conventional methods known in the art. EXAMPLE

[0032] In this example, the rubber substrate is 20 mm x 20 mm fluoroether rubber or nitrile rubber (surface finish Ra < 200 nm, thickness 2 mm); the preparation process is as follows:

[0033] 1) First, the cleaned rubber substrate is fixed in the vacuum chamber, and vacuumed to 2 x 10 -4Pa; then Ar gas was injected, and the pressure was kept at about 0.35 Pa; a Cu target and a Cr target for magnetron sputtering were installed in the vacuum chamber, a 135° magnetic filtering elbow was connected between the Cu target and the Cr target, and a Ti arc target for magnetic filtering cathode arc deposition was fixed at the other end of the 135° magnetic filtering elbow;

[0034] 2) The Ti arc target was turned on, the current of the Ti arc target was set to 80 A, the bias voltage was 350-400 V, the magnetic filtering coils close to and away from the Ti arc target were set to 25 A and 35 A respectively, the rotation speed of the rubber substrate was 1 r / min, and the deposition time was 15 min;

[0035] 3) The remaining conditions were kept unchanged, the current of the Ti arc target was adjusted to 125 A, the Cr target was turned on, the current of the Cr target was gradually increased from 0 A to 12 A within 20 min, the bias voltage was 70 V, and the deposition time was 20 min;

[0036] 4) The remaining conditions were kept unchanged, the Cu target was turned on, the current of the Cu target was set to 5 A, the bias voltage was 70 V, and the deposition time was 10 min;

[0037] 5) TiCr layers and Cu layers were deposited alternately for 150 cycles; when the TiCr layers were deposited, the Cu target was turned off, the process parameters of the Ti target and the Cr target were kept unchanged, and the deposition time was 5 min; when the Cu layers were deposited, the Ti target and the Cr target were turned off, the process parameters of the Cu target were kept unchanged, and the deposition time was 5 min.

[0038] The structural characterization and performance evaluation were as described above.

Claims

1. A method for preparing a TiCr / Cu multilayer composite film on a rubber surface, characterized by, First, a Ti metal adhesive layer is deposited on the surface of a rubber substrate by magnetic filtering cathodic arc deposition, and then a TiCr gradient mixed layer, a TiCrCu gradient bearing layer and a surface layer composed of TiCr layers and Cu layers are deposited in sequence by high-power pulsed magnetron sputtering, with the specific process being as follows: 1) The cleaned rubber substrate is fixed in the vacuum chamber, and the vacuum is extracted to 2x10 -4 Pa; The Cu target and Cr target for magnetron sputtering are installed in the vacuum chamber, the curved magnetic filter tube is connected between the Cu target and the Cr target, and the Ti arc target for magnetic filter cathode arc deposition is fixed at the other end of the curved magnetic filter tube; 2) Turn on the Ti arc target for magnetic filtering cathodic arc deposition, set the Ti target current to 75-85 A, the bias voltage to 350-400 V, the Ar gas pressure to 0.3-0.5 Pa, the rubber substrate rotation speed to 1-2 r / min, and the deposition time to 15-20 min; 3) Keep the other conditions unchanged, adjust the Ti arc target current to 120-130 A, turn on the Cr target for magnetron sputtering, gradually increase the current from 0 A to 12 A within 20 min, set the bias voltage to 65-75 V, and the deposition time to 20-25 min; 4) Keep the other conditions unchanged, turn on the Cu target for magnetron sputtering, set the current to 5-10 A, the bias voltage to 65-75 V, and the deposition time to 10-15 min; 5) Deposit the TiCr layer and then the Cu layer, and repeat the process for 140-160 cycles; When depositing the TiCr layer, turn off the Cu target for magnetron sputtering, keep the process parameters of the Ti arc target for magnetic filtering cathodic arc deposition and the Cr target for magnetron sputtering unchanged, and deposit for 5-10 min; when depositing the Cu layer, turn off the Ti arc target for magnetic filtering cathodic arc deposition and the Cr target for magnetron sputtering, keep the process parameters of the Cu target for magnetron sputtering unchanged, and deposit for 5-10 min.

2. The method for preparing a TiCr / Cu multilayer composite film on a rubber surface as described in claim 1, characterized in that, In step 1), the rubber substrate is one of nitrile rubber, fluororubber and silicone rubber.

3. The method for preparing a TiCr / Cu multilayer composite film on a rubber surface as described in claim 1, characterized in that, In step 2), the coil current near the Ti arc target for magnetic filtering cathodic arc deposition on the curved magnetic filtering tube is 20-30 A, and the central magnetic field strength is 80-90 Gauss; the coil current near the vacuum chamber is 30-40 A, and the central magnetic field strength is 100-110 Gauss.

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