A fast ultra-low friction rubber surface layer and a method for constructing the same

Abstract

The application discloses a kind of fast ultra-low friction rubber surface layer and its construction method, carbon film is prepared on the surface of rubber using gas deposition technology, MXene-based two-dimensional material is intercalated with other two-dimensional materials to prepare two-dimensional intercalation material, and finally it is sprayed to the surface of carbon film to obtain.The two-dimensional intercalation material will quickly form a heterojunction pair under the action of friction normal load, thereby effectively shortening the friction and running-in time, and then quickly realizing the ultra-low friction property.The process is not affected by friction load, environment and other external factors, and can be applied to various complex application conditions.The process of the application is easy to control, and the obtained rubber surface can realize ultra-low friction in a very short time, and is easy to realize large-area industrial application.

Description

Technical Field

[0001] This invention relates to a rapid ultra-low friction rubber surface layer and its construction method, and more particularly to a method for preparing a rubber surface carbon film + two-dimensional intercalation material, which is used for the preparation of dynamic sealing components and belongs to the fields of solid lubricating materials and tribology. Background Technology

[0002] Modern industrial equipment contains numerous sealing devices to prevent leakage of working media and the intrusion of external dust and foreign matter. Leakage of the sealed media can lead to material loss and equipment damage, or even fire and explosion. Most dynamic seal leakage accidents are related to the failure of the seal itself. Rubber, with its excellent elasticity, resilience, and pressure resistance, is the most commonly used sealing material. However, after being installed in the sealing groove, rubber dynamic seals are deformed by the high-pressure medium and experience extremely high friction (µ>1) due to the frictional heat generated by the frictional contact with the steel groove wall and sealing rod under cyclic stress. This high friction easily softens the rubber seal and causes rapid wear and failure, allowing the high-pressure sealing medium to leak from the damaged area, thus affecting the safe and reliable operation of the equipment. Therefore, solving the problem of rubber seal wear and failure must start with reducing friction.

[0003] Carbon thin films possess excellent properties such as low adhesion to steel, low deposition temperature (≤100℃, which will not cause fatal damage to the nitrile rubber matrix), controllable composition and mechanical strength, diverse structures (such as multi-micro / nano structures, multi-element doping, etc.), and low friction and wear, making them an ideal coating for achieving low friction on rubber surfaces. However, carbon thin films undergo a break-in period in the initial stage of friction (before reaching stable low friction), during which their coefficient of friction is relatively high (≥0.1, or even higher), thus exacerbating abnormal wear and failure of the film. If the break-in period is long, it will lead to decreased lubrication efficiency, wasted resources and time, and even failure of the entire sealing system. Therefore, how to construct a fast ultra-low friction rubber surface is of paramount importance in solving the future wear and failure of rubber seals. Summary of the Invention

[0004] The purpose of this invention is to provide a rapid ultra-low friction rubber surface layer and its construction method. This method utilizes vapor deposition to prepare a carbon thin film on the rubber surface, while simultaneously intercalating MXene-based two-dimensional materials with other two-dimensional materials to prepare a two-dimensional intercalated material. Finally, the two-dimensional intercalated material is sprayed onto the carbon thin film surface. During friction, under the action of a normal friction load, the two-dimensional intercalated material rapidly forms heterojunction pairs at the friction interface, effectively shortening the friction break-in time and thus quickly achieving ultra-low friction characteristics. Furthermore, this process is unaffected by friction loads, environmental factors, or other external factors, making it applicable to various complex application conditions.

[0005] I. Rapid Ultra-Low Friction Rubber Surface Layer and Its Construction Method

[0006] The present invention provides a fast, ultra-low friction rubber surface layer. First, a carbon film is prepared on the rubber surface using vapor deposition technology. Then, an MXene-based two-dimensional material is intercalated with other two-dimensional materials to prepare a two-dimensional intercalation material. Finally, the intercalation material is sprayed onto the surface of the carbon film.

[0007] The above-mentioned method for preparing a rapid ultra-low friction rubber surface layer includes the following steps:

[0008] 1) Cleaning the rubber substrate: Cut the rubber sheet into 20×20mm pieces. 2 The rubber sheet is immersed in a soapy water solution at 50-60℃ and ultrasonically cleaned for 30-45 minutes to remove grease and dirt from the rubber surface; then it is taken out and immersed in distilled water at 90-95℃ and ultrasonically cleaned for 20-30 minutes to remove any residual soapy water solution; finally, it is dried with dry nitrogen gas and placed in a drying oven at 100-120℃ for 20-30 minutes to evaporate any residual moisture from the rubber surface; the above process is repeated 4-5 times.

[0009] The rubber substrate is one of nitrile rubber, hydrogenated nitrile rubber, silicone rubber and EPDM rubber, with a surface roughness of ≤200nm and a thickness of 2~4mm.

[0010] 2) Preparation of amorphous carbon thin films: Turn on the graphite target sputtering power supply, adjust the target-substrate distance to 8~12cm, the target current to 3A, the argon flow rate to 45~60sccm, the Ar / CH4 flow ratio to 1.5:1, the substrate bias voltage to -700V, the gas pressure to 0.5~0.8Pa, the duty cycle to 40~45%, the frequency to 60~70KHz, and the deposition time to 120~150min;

[0011] The amorphous carbon film is a hydrogen-containing or hydrogen-free amorphous carbon film with a thickness of 500 nm to 1.0 µm.

[0012] 3) Intercalation treatment of MXene-based 2D materials with other 2D materials: ① After drying, MXene powder is evenly distributed on the sample stage of the gas phase intercalation reaction chamber, and the vacuum is evacuated to 10. -2 Up to 10 -3 ① After Torr, hydrogen gas is introduced; ② The MXene sample in the reaction chamber is heated to 300~400℃ and kept at that temperature for 1~3h to ensure that hydrogen molecules are fully diffused into the interlayer of the MXene two-dimensional sheet; ③ The hydrogen gas is turned off and the reaction chamber is allowed to cool naturally to room temperature before being removed; ④ The sample is dispersed in an organic solvent with other two-dimensional materials and ultrasonically dispersed to obtain a two-dimensional intercalated material.

[0013] The MXene-based two-dimensional material is one or more of Ti-based, V-based, and Mo-based MXene; the other two-dimensional materials are one or more of graphene-based, molybdenum disulfide, and boron nitride; the mass ratio of the MXene-based two-dimensional material to other two-dimensional materials is 1~1.5:1; and the organic solvent is one of anhydrous ethanol and acetone.

[0014] 4) Spraying two-dimensional intercalation material: The above two-dimensional intercalation material solution is loaded into a portable sprayer, and the carbon film is preheated at the same time. Finally, the two-dimensional intercalation material is uniformly sprayed onto the surface of the amorphous carbon film. After the solvent has completely evaporated, the fast ultra-low friction rubber surface of the present invention can be obtained.

[0015] The carbon film is preheated at 80~100℃, the spray gun working pressure is 2~4MPa, the spray gun moves at a constant speed of 2~4 cm / s, and the nozzle is 20~30cm away from the substrate.

[0016] Figure 1 This is a schematic diagram of the cross-sectional structure of the rapid ultra-low friction rubber surface constructed according to the present invention. It can be seen that during the friction process, under the action of the normal friction load, the two-dimensional intercalated material rapidly forms heterojunction pairs at its friction contact interface, thereby effectively shortening the friction break-in time and quickly achieving ultra-low friction characteristics. The present invention effectively overcomes the technical challenge of the long friction break-in period of hard carbon-based coatings on soft rubber surfaces. Furthermore, the process is easy to control, highly operable, and the obtained rubber surface can quickly achieve ultra-low friction, making it easy to realize large-scale industrial applications.

[0017] II. Rubber Surface Performance Testing Method Constructed by the Invention

[0018] 1. Break-in time

[0019] The friction and break-in time of the rubber surface constructed in this invention was tested using a ball-disc rotary friction and wear tester. The results showed that the break-in time was 30 to 60 seconds.

[0020] 2. Coefficient of friction

[0021] Figure 2 This is a graph showing the friction coefficient of the rapidly low-friction rubber surface constructed according to this invention. The tribological properties of the rubber surface constructed according to this invention were evaluated using a tribological testing machine. The friction conditions were: ball-disc rotation mode, normal load 10N, friction pair φ6mm GCr15 steel ball, and atmospheric environment. The results show that the friction coefficient of conventional pure carbon film is relatively high (>0.18), while the friction coefficient of the rubber surface constructed according to this invention is significantly reduced (0.04~0.08).

[0022] In summary, the present invention has the following advantages compared with the prior art:

[0023] 1. Two-dimensional intercalation material is sprayed onto the surface of a carbon thin film. During the friction process, under the action of normal load, the friction contact interface of the two-dimensional intercalation material will quickly form a heterojunction pair, thereby effectively shortening the friction break-in time and thus quickly achieving ultra-low friction characteristics.

[0024] 2. This invention effectively overcomes the technical challenge of the long friction break-in period of hard carbon-based coatings on soft rubber surfaces. Moreover, this process is not affected by friction loads, environment, or other external factors, and can be applied to a variety of complex working conditions.

[0025] 3. The process of this invention is simple and easy to control, highly operable, and the constructed rubber surface can quickly achieve ultra-low friction characteristics, making it easy to realize large-scale industrial applications. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the cross-sectional structure of the high-speed ultra-low friction rubber surface constructed according to the present invention.

[0027] Figure 2 The friction coefficient curves of the rubber surface constructed in this invention, the original rubber, and the single-layer carbon film on its surface are shown. Detailed Implementation

[0028] The following specific embodiments further illustrate the construction method and performance of the rapid ultra-low friction rubber surface of the present invention.

[0029] Example 1

[0030] (1) Cut a 300×300×2mm black nitrile rubber sheet (surface smoothness Ra<200nm, thickness 3mm) into 20×20mm pieces. 2 The rubber sheet was ultrasonically cleaned in a 60°C soapy water solution for 30 minutes to remove grease and dirt from the rubber surface; then it was removed and ultrasonically cleaned in 90°C distilled water for 30 minutes to remove any remaining soapy water solution; finally, it was dried with dry nitrogen gas and placed in a drying oven at 120°C for 20 minutes to evaporate any residual moisture from the rubber surface. The above process was repeated 5 times.

[0031] (2) Place the cleaned rubber substrate into the magnetron sputtering vacuum chamber, close the vacuum chamber door, and evacuate to ≤2.0×10⁻⁶. –3 Pa; Turn on the graphite target sputtering power supply, adjust the target-substrate distance to 8 cm, target current to 3 A, argon flow rate to 45 sccm, CH4 flow rate to 30 sccm, substrate bias to -700 V, gas pressure to 0.5 Pa, duty cycle to 40%, frequency to 60 kHz, and deposition time to 120 min. After deposition, wait for the temperature inside the vacuum chamber to cool to room temperature before removing the sample.

[0032] (3) First, dry the Ti3C2MXene powder in a vacuum oven at 80°C for 12 hours. Then, place the dried MXene powder sample on the sample stage of the vapor phase intercalation reaction chamber and evacuate the reaction chamber to 10°C. -2 Up to 10 -3 Torr. Introduce 99.999% pure hydrogen gas into the reaction chamber, and simultaneously adjust the chamber pressure to 1 atm (atmosphere) to ensure the entire chamber is filled with hydrogen. Heat the MXene sample in the reaction chamber to 300°C and maintain this temperature for 1 hour to ensure sufficient time for hydrogen molecules to diffuse into the MXene interlayer and form a stable Ti3C2MXene material with expanded interlayer spacing. After the above process is complete, turn off the hydrogen gas and allow the reaction chamber to cool naturally to room temperature in a hydrogen atmosphere.

[0033] (4) Take 25 mg of Ti3C2MXene and 25 mg of MoS2 powder prepared by the above method, dissolve them in 50 mL of anhydrous ethanol, and use an ultrasonic device to perform ultrasonic treatment at a power of 300 W for 60 minutes to ensure full dispersion to obtain Ti3C2MXene / MoS2 two-dimensional intercalation material.

[0034] (5) The Ti3C2MXene / MoS2 two-dimensional intercalation material solution prepared above is loaded into a portable sprayer, and the carbon film prepared in step (2) is preheated to 80°C. A nitrogen cylinder is connected to the spray gun, and the flow rate is set to 15 L / min to ensure that the internal environment of the spray gun is a nitrogen atmosphere during the operation. The working pressure of the air spray gun is set to 2 MPa, the nozzle is 20 cm away from the substrate, and the spraying is completed by moving at a uniform speed of 2 cm / s. After the spraying is completed, the substrate is kept heated at 100°C for 30 minutes to ensure that the anhydrous ethanol is completely evaporated, and then naturally cooled to room temperature to obtain the rubber surface constructed in this invention. The coefficient of friction of the nitrile rubber surface reaching a stable state under a 10N load is 0.05, and the break-in period takes only 45 seconds.

[0035] Example 2

[0036] (1) The pre-cleaning steps for silicone rubber are the same as in Example 1. Wherein: the surface finish of silicone rubber Ra < 200 nm and the thickness is 3 mm.

[0037] (2) Place the cleaned rubber substrate into the magnetron sputtering vacuum chamber, close the vacuum chamber door, and evacuate to ≤2.0×10⁻⁶. –3 Pa; Turn on the graphite target sputtering power supply, adjust the target-substrate distance to 8 cm, target current to 3 A, argon flow rate to 45 sccm, substrate bias to -700 V, gas pressure to 0.5 Pa, duty cycle to 40%, frequency to 60 kHz, and deposition time to 120 min. After deposition, wait for the temperature inside the vacuum chamber to cool to room temperature before removing the sample.

[0038] (3) First, dry the V4C3MXene powder in a vacuum oven at 80°C for 12 hours. Then, place the dried MXene powder on the sample stage of the vapor phase intercalation reaction chamber and evacuate the reaction chamber to 10°C. -2 Up to 10 -3 Torr. Hydrogen gas with a purity of 99.999% was introduced into the reaction chamber, and the pressure in the reaction chamber was adjusted to 1 atm (atmosphere) to ensure that the hydrogen gas completely filled the entire reaction chamber. The MXene sample in the reaction chamber was heated to 400°C and maintained for 2 hours to ensure that hydrogen molecules had sufficient time to diffuse into the MXene interlayer and form a stable V4C3MXene material with an expanded interlayer spacing. After the above process was completed, the reaction chamber was allowed to cool naturally to room temperature in a hydrogen atmosphere.

[0039] (4) Take 25 mg of V4C3MXene and 25 mg of graphene powder prepared above, dissolve them in 50 mL of acetone solution, and use an ultrasonic device to perform ultrasonic treatment at a power of 300 W for 60 minutes to ensure full dispersion to obtain V4C3MXene / graphene two-dimensional intercalation material.

[0040] (5) The V4C3MXene / graphene two-dimensional intercalation material solution prepared above is loaded into a portable sprayer, and the carbon film prepared in step (2) is preheated to 100°C. A nitrogen cylinder is connected to the spray gun, and the flow rate is set to 15 L / min to ensure that the internal environment of the spray gun is a nitrogen atmosphere during the operation. The working pressure of the air spray gun is set to 4 MPa, the nozzle is 30 cm away from the substrate, and it is moved at a constant speed of 4 cm / s to complete the spraying. After the spraying is completed, the substrate is kept heated at 100°C for 30 minutes to ensure that the acetone solution is completely evaporated, and then naturally cooled to room temperature to obtain the rubber surface constructed in this invention. The coefficient of friction of this silicone rubber surface reaching a stable state under a 10 N load is 0.08, and the break-in period takes only 30 seconds.

[0041] Example 3

[0042] (1) The pre-cleaning steps for hydrogenated nitrile rubber are the same as in Example 1. Wherein: the surface finish of silicone rubber Ra < 200 nm and the thickness is 2 mm.

[0043] (2) The preparation of a hydrogen-free carbon film on the surface of hydrogenated nitrile rubber is the same as in Example 2;

[0044] (3) First, the Mo2C MXene powder was dried in a vacuum oven at 80°C for 12 hours. Then, the dried MXene powder sample was placed on the sample stage of the vapor phase intercalation reaction chamber, and the reaction chamber was evacuated to 10°C. -2 ~10 -3Torr. Hydrogen gas with a purity of 99.999% was introduced into the reaction chamber, and the pressure in the reaction chamber was adjusted to 1 atm (atmosphere) to ensure that the hydrogen gas completely filled the entire reaction chamber. The MXene sample in the reaction chamber was heated to 350°C and maintained for 1.5 hours to ensure that hydrogen molecules had sufficient time to diffuse into the MXene interlayer and form a stable Mo2C MXene material with expanded interlayer spacing. After the above process was completed, the reaction chamber was allowed to cool naturally to room temperature in a hydrogen atmosphere.

[0045] (4) Take 30 mg of Mo2C MXene and 20 mg of boron nitride powder prepared above, dissolve them in 50 mL of acetone solution, and use an ultrasonic device to perform ultrasonic treatment at a power of 300 W for 60 minutes to ensure full dispersion to obtain Mo2C MXene / graphene two-dimensional intercalation material.

[0046] (5) The prepared Mo2C MXene / BN two-dimensional intercalation material solution was loaded into a portable sprayer, and the carbon film prepared in step (2) was preheated to 90°C. A nitrogen cylinder was connected to the spray gun, and the flow rate was set to 15 L / min to ensure that the internal environment of the spray gun was a nitrogen atmosphere during the operation. The working pressure of the air spray gun was set to 3 MPa, the nozzle was 25 cm away from the substrate, and the nozzle was moved at a constant speed of 3 cm / s to complete the spraying. After the spraying was completed, the substrate was kept heated at 100°C for 30 minutes to ensure that the acetone was completely evaporated and then cooled naturally to room temperature to obtain the rubber surface constructed in this invention. The coefficient of friction of the hydrogenated nitrile rubber surface reaching a stable state under a 10N load was 0.06, and the break-in period took only 60 seconds.

Claims

1. A kind of fast ultra-low friction rubber, first carbon film is prepared on the surface of rubber using gas deposition technology, then MXene-based two-dimensional material is intercalated with other two-dimensional materials to prepare two-dimensional intercalation material, finally it is sprayed to the surface of carbon film and obtained; Wherein the step of intercalating MXene-based two-dimensional material with other two-dimensional materials includes: ① After drying, MXene powder is evenly distributed on the sample stage of the vapor phase intercalation reaction chamber, and a vacuum is drawn to 10. -2 Up to 10 -3 ① After Torr, hydrogen gas is introduced; ② The MXene sample in the reaction chamber is heated to 300~400℃ and kept at that temperature for 1~3h to ensure that hydrogen molecules are fully diffused into the interlayer of the MXene two-dimensional sheets; ③ The hydrogen gas is turned off and the reaction chamber is allowed to cool naturally to room temperature before being removed; ④ The sample is dispersed with other two-dimensional materials in an organic solvent and ultrasonically dispersed until uniform to obtain the two-dimensional intercalated material.

2. A process for the preparation of the instant ultra-low friction rubber as claimed in claim 1, characterized in that, Including the following steps: 1) Cleaning the rubber substrate: Cut the rubber sheet into 20×20mm pieces. 2 The rubber sheet is immersed in a soapy water solution at 50-60℃ and ultrasonically cleaned for 30-45 minutes to remove grease and dirt from the rubber surface; then it is taken out and immersed in distilled water at 90-95℃ and ultrasonically cleaned for 20-30 minutes to remove residual soapy water solution; finally, it is dried with dry nitrogen gas and placed in a drying oven at 100-120℃ for 20-30 minutes to evaporate the residual moisture on the rubber surface; the above process is repeated 4-5 times. 2) Amorphous carbon film preparation: open graphite target sputtering power, adjust the target-substrate distance to 8~12cm, target current is 3A, argon flow is 45~60sccm, Ar / CH4 flow ratio is 1.5:1, substrate bias is -700V, gas pressure is 0.5~0.8Pa, duty cycle is 40~45%, frequency is 60~70KHz, deposition time is 120~150min; 3) Intercalation treatment of MXene-based 2D materials with other 2D materials: ① After drying, MXene powder is evenly distributed on the sample stage of the gas phase intercalation reaction chamber, and the vacuum is evacuated to 10. -2 Up to 10 -3 ① After Torr, hydrogen gas is introduced; ② The MXene sample in the reaction chamber is heated to 300~400℃ and kept at that temperature for 1~3h to ensure that hydrogen molecules are fully diffused into the interlayer of the MXene two-dimensional sheets; ③ The hydrogen gas is turned off and the reaction chamber is allowed to cool naturally to room temperature before being removed; ④ The sample is dispersed with other two-dimensional materials in an organic solvent and ultrasonically dispersed to obtain a two-dimensional intercalated material. 4) Spray two-dimensional intercalation material: the above-mentioned two-dimensional intercalation material solution is loaded into portable spraying instrument, at the same time, the carbon film is preheated, finally the two-dimensional intercalation material is uniformly sprayed to the surface of amorphous carbon film, and the fast ultra-low friction rubber can be obtained after the solvent is completely volatilized.

3. The method for preparing rapid ultra-low friction rubber as described in claim 2, characterized in that, In step 1), the rubber substrate is one of nitrile rubber, hydrogenated nitrile rubber, silicone rubber and ethylene-propylene-diene rubber, the rubber surface roughness is ≤200nm, and the rubber thickness is 2~4mm.

4. The method for preparing rapid ultra-low friction rubber as described in claim 2, characterized in that, In step 2), the amorphous carbon film is hydrogen-containing or non-hydrogen-containing amorphous carbon film, and the film thickness is 500nm~1.0µm.

5. The method for preparing rapid ultra-low friction rubber as described in claim 2, characterized in that, In step 3), the MXene-based two-dimensional material is one or several of Ti-based, V-based and Mo-based MXene; other two-dimensional materials are one or several of graphene, molybdenum disulfide and boron nitride; the mass ratio of MXene-based two-dimensional material to other two-dimensional material is 1~1.5:1, and the organic solvent is one of anhydrous ethanol and acetone.

6. The method for preparing a rapid ultra-low friction rubber as described in claim 2, characterized in that: The preheating temperature of the carbon film is 80~100℃, the working pressure of the spray gun is 2~4MPa, the uniform speed of the spray gun is 2~4cm / s, and the nozzle distance from the substrate is 20~30cm.

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