Graphite-like carbon film and preparation method and application thereof

Abstract

The invention relates to a graphite-like carbon film and a preparation method and application thereof, the graphite-like carbon film is a hydrogen-free graphite-like carbon film, the graphite-like carbon film comprises an enhancement layer located on the surface of a substrate and a graphite-like carbon working layer located on the enhancement layer, and the enhancement layer comprises a Cr base layer located on the surface of the substrate and a Cr / C gradient transition layer located on the Cr base layer; the graphite-like carbon working layer is doped with metal Cr, and the doping amount of the metal Cr is 0.5%-5% by atomic percent; in the graphite-like carbon film, the ratio of sp2 C to sp3 C is 1.8 to 4.0. Graphite-like carbon films with different microstructures are prepared by regulating and controlling deposition bias by utilizing a magnetron sputtering technology, and meanwhile, a high-hydrogen-content nano-clustered diamond-like carbon film is selected as a heterogeneous matching pair of the graphite-like carbon film, so that macro-scale super-lubricity of the bias-induced graphite-like carbon film is realized in an inert gas dry nitrogen atmosphere; and the friction coefficient is as low as 0.0035.

Description

Technical Field

[0001] The present application relates to the field of super-lubricity and friction and wear of mechanical parts, and in particular to a bias-induced diverse microstructured graphite-like carbon film and its preparation method and application. Background Art

[0002] In high-end equipment such as aviation and aerospace, friction and wear are critical issues that limit equipment performance and lifespan. Moving components such as precision bearings, harmonic reducers, momentum wheels, and slide rails have long faced lubrication challenges under extreme operating conditions: high vacuum environments cause traditional lubricants to fail, alternating loads induce interface fatigue wear, and high temperatures cause lubrication failure. These friction and wear issues not only cause significant economic losses but also directly threaten the safe operation of critical equipment. Therefore, there is an urgent need to develop new lubricating materials suitable for extreme operating conditions and to construct corresponding friction pairs to reduce friction and wear.

[0003] Superlubricity refers to a lubrication state with a coefficient of friction less than 0.01, one to two orders of magnitude lower than that of conventional lubrication. Graphite-like carbon films, through elemental doping, multi-layered, and multi-phase structural toughening, can reduce internal stress and enhance film-substrate adhesion. These intrinsic material properties of high hardness, low friction, and enhanced toughness make them a preferred lubricant. However, in a dry nitrogen environment, graphite-like carbon films exhibit a very high friction coefficient and wear rate. Dangling bonds on the film surface cause strong adhesion at the friction interface, accelerating graphitization at the friction interface, leading to rapid film failure, increased wear between friction pairs, and even seizure, seriously impacting the safe and stable operation of high-end equipment. Furthermore, the high internal stress and low film-substrate adhesion of graphite-like carbon films under these conditions restrict their mechanical and tribological properties and their industrial application. Optimizing preparation parameters and doping with heterogeneous elements can effectively improve the internal stress and film-substrate adhesion of graphite-like carbon films. Although graphite-like carbon films doped with elements such as Ag, Cu, and Au are beneficial to improving the tribological properties of the films, their own "softening effect" weakens the mechanical strength of the films to a certain extent, which is not conducive to the application of the films in heavy-load environments.

[0004] Therefore, rationally regulating graphite-like carbon films and achieving stable superlubricity by constructing heterogeneous friction pairs is one of the effective ways to solve the above problems. Summary of the Invention

[0005] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of protection of this application.

[0006] In the preparation of graphite-like carbon films by magnetron sputtering, the internal microstructure and sp 2 C / sp 3The hybridization ratio of C, surface roughness and other intrinsic structures of the film are adjusted to obtain graphite-like carbon films with different properties. At the same time, doping with Cr can reduce the internal stress of the graphite-like carbon film and enhance the film-substrate bonding strength. Cr and C will form an amorphous composite structure to improve the film's hardness and load-bearing capacity. On the one hand, the graphite-like carbon film doped with trace Cr improves the overall mechanical properties of the film. On the other hand, its high elasticity and low surface energy give it excellent anti-friction and anti-wear properties.

[0007] The technical problem to be solved by the present application is to provide a method for preparing bias-induced graphite-like carbon films with diverse microstructure morphologies.

[0008] Another technical problem to be solved by the present application is to provide a bias-induced graphite-like carbon film to achieve an ultra-slip friction pair system.

[0009] In the bias-induced graphite-like carbon film described in this application, the magnetron sputtering deposition bias is regulated to 15-50 V to prepare graphite-like carbon films with different microstructures and mechanical properties. At the same time, it can be used to construct a friction pair with a high-hydrogen-containing nanoclustered carbon film dual ball to achieve super-slippery in a dry nitrogen atmosphere.

[0010] To solve the above problems, this application provides the following technical solutions: The first aspect of the present application provides a graphite-like carbon film, comprising a reinforcement layer located on a surface of a substrate and a graphite-like carbon working layer located on the reinforcement layer; wherein the graphite-like carbon film is a hydrogen-free graphite-like carbon (GLC) film.

[0011] In an exemplary embodiment, the enhancement layer includes a Cr primer layer located on the surface of the substrate and a Cr / C gradient transition layer located on the Cr primer layer.

[0012] In an exemplary embodiment, the graphite-like carbon working layer is doped with a trace amount of metal Cr to perform strengthening and toughening control.

[0013] In an exemplary embodiment, the graphite-like carbon working layer has a doping amount of metal Cr of 0.5%-5% in atomic percentage.

[0014] In an exemplary embodiment, the thickness of the reinforcement layer is 1.0-2.0 μm.

[0015] In an exemplary embodiment, the graphite-like carbon working layer has a thickness of 1.0-4.0 μm.

[0016] In an exemplary embodiment, the graphite-like carbon film has a characteristic hardness value of 10-25 GPa.

[0017] In an exemplary embodiment, the graphite-like carbon film has a Young's modulus of 100-200 GPa.

[0018] In an exemplary embodiment, the critical load of the graphite-like carbon film is 40 N-55 N.

[0019] In an exemplary embodiment, the surface roughness of the graphite-like carbon film is 1 nm-10 nm.

[0020] In an exemplary embodiment, in the graphite-like carbon film, sp 2 C / sp 3 The ratio of C is 1.8-4.0.

[0021] In an exemplary embodiment, the substrate is selected from a single crystal silicon wafer or a sheet / spherical metal; Optionally, the sheet / spherical metal is selected from any one of quenched GCr15 bearing steel, high temperature alloy, stainless steel, titanium alloy, and high entropy alloy.

[0022] A second aspect of the present application provides a method for preparing the graphite-like carbon film, which is prepared by magnetron sputtering, comprising the following steps: 1) Surface pretreatment of substrate; 2) Preparation of reinforcement layer; 3) Preparation of chromium-doped graphite-like carbon working layer.

[0023] In an exemplary embodiment, in step 1), the surface pretreatment of the substrate includes polishing the substrate to mirror-level smoothness, then performing ultrasonic cleaning, and performing high-energy ion beam / particle beam cleaning under high vacuum.

[0024] In an exemplary embodiment, in step 1), the ultrasonic cleaning step includes: wiping the polished substrate surface with alcohol and acetone, and then placing it in alcohol and acetone solutions for ultrasonic treatment for 10-30 minutes respectively; wherein the alcohol cleaning number is 1-2 times, the acetone cleaning number is greater than 2 times, and then quickly drying for use.

[0025] In an exemplary embodiment, in step 1), performing high-energy ion beam / particle beam cleaning under high vacuum comprises: placing the cleaned and dried substrate into a rotating rack in a coating chamber, and evacuating the vacuum to less than 5×10 -3 Pa, introduce inert gas argon, load the high-energy ion source for primary cleaning, and then use the metal chromium target for secondary cleaning.

[0026] In an exemplary embodiment, when a high-energy ion source is loaded for one cleaning, the ion source current is 1-5 A, the cleaning time is 20-40 min, and the gas pressure in the chamber is 1-3 Pa.

[0027] In an exemplary embodiment, when a metal chromium target is used for secondary cleaning, the chromium target current is 0.1-0.5 A, the cleaning time is 20-40 min, and the pressure in the chamber is 1-3 Pa.

[0028] In an exemplary embodiment, in step 2), the preparation of the enhancement layer includes: controlling the flow rate of argon gas, a sputtering inert gas source, to 5-30 sccm, turning on the metal chromium target, controlling the deposition current to 4-7.5 A, and the deposition time to 30-120 min to prepare a Cr base layer; then simultaneously turning on the non-metallic carbon target and the metal chromium target to prepare a Cr / C gradient transition layer, wherein the deposition current of the metal chromium target is 3-4 A, the deposition current of the non-metallic carbon target is 2.5-3.5 A, and the deposition time is 30-240 min.

[0029] In an exemplary embodiment, in step 2), the operating voltage of the carbon target is controlled within a range of 250-650 V, and the operating voltage of the chromium target is controlled within a range of 50-350 V during the entire deposition process.

[0030] In an exemplary embodiment, in step 2), the bias voltage is 70-150 V during the entire enhancement layer deposition process.

[0031] In an exemplary embodiment, in step 3), the graphite-like carbon working layer is regulated by co-sputtering a metal chromium target and a non-metallic carbon target to form a multi-element doped carbon film, including: controlling the flow rate of argon gas, a sputtering inert gas source, to 5-30 sccm and a deposition bias voltage to 15-50 V; simultaneously turning on the metal chromium target and the non-metallic carbon target, with the operating voltage of the non-metallic carbon target being 250-650 V and the operating current being 0.5-7.6 A; and the operating voltage of the metal Cr target being 50-350 V and the operating current being 0.1-0.9 A; keeping other gas pressure conditions unchanged and depositing for 2-8 h, a graphite-like carbon working layer with diverse microstructure morphology is obtained.

[0032] In an exemplary embodiment, in step 3), the deposition bias voltage is 25-50V.

[0033] In an exemplary embodiment, in step 3), the deposition bias voltage is 30 V.

[0034] In an exemplary embodiment, the method regulates the microstructure of the graphite-like carbon working layer by bias voltage, and the resulting microstructure is distributed with: 2 C / sp 3 C high ratio of amorphous graphite carbon, sp 2 C / sp 3 Amorphous graphite-like carbon with moderate C ratio, sp 2C / sp 3 C low ratio vertical ordered growth graphite-like carbon.

[0035] The third aspect of the present application provides a graphite-like carbon film prepared by the above method.

[0036] A fourth aspect of the present application provides a friction pair, which is composed of the above-mentioned graphite-like carbon film and high-hydrogen-content amorphous carbon film dual spheres.

[0037] In an exemplary embodiment, the high hydrogen content amorphous carbon film dual sphere is a high hydrogen content nanoclustered amorphous carbon film dual sphere; for example, a GCr15 steel ball with a diameter of 6 mm coated with a high hydrogen content amorphous carbon film.

[0038] The fifth aspect of the present application provides a method for achieving super-slippery properties using the above-mentioned graphite-like carbon film.

[0039] In an exemplary embodiment, the method includes: forming a friction pair of the graphite-like carbon film and a high-hydrogen-content amorphous carbon film dual ball to achieve super-lubricity in a nitrogen atmosphere.

[0040] In an exemplary embodiment, the friction coefficient of the dual spheres of the graphite-like carbon film and the highly hydrogenated amorphous carbon film in an inert dry nitrogen atmosphere is less than 0.01.

[0041] Compared with the prior art, this application has the following advantages: 1. This application uses magnetron sputtering technology to prepare graphite-like carbon films, and adopts a Cr / C gradient transition design to make the film have a high film-base bonding strength.

[0042] 2. The present application regulates the deposition bias voltage during the deposition of the graphite-like carbon thin film working layer, thereby regulating the microstructure and performance of the graphite-like carbon thin film working layer.

[0043] 3. The bias-induced graphite-like carbon film prepared in this application exhibits different mechanical properties. In particular, when the graphite-like carbon film obtained by deposition bias voltage of 30 V is used as a friction pair with a high hydrogen-containing nanoclustered carbon film dual ball, friction tests are carried out using an Anton Paar friction tester. The results show that: the sp 2 The C amorphous structure is dominant and is easy to form a low shear lubrication transfer film at the sliding interface with the high hydrogen content nanoclustered carbon film under pressure induction. This easy shear hydrogen passivation sp 2 The generation of C lubricating phase realizes the robust superlubricity (friction coefficient less than 0.01) of graphite-like structured carbon film under dry nitrogen and wide load range.

[0044] Other features and advantages of the present application will be described in the following description or understood through implementation of the present application. Other advantages of the present application can be realized and obtained through the solutions described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0046] Figure 1 The friction coefficient curves obtained for the dual balls of graphite-like carbon film and highly hydrogenated amorphous carbon film deposited at a bias voltage of 30 V in this application were obtained. Super-slip performance was achieved in all cases where loads of 5-20 N were applied in the friction experiment.

[0047] Figure 2 The friction coefficient curve obtained for the dual ball of graphite-like carbon film and highly hydrogenated amorphous carbon film deposited with a bias voltage of 50 V in this application. The load applied in the friction experiment was 5 N to achieve super-slip.

[0048] Figure 3 Comparison of friction coefficient curves obtained for dual balls of graphite-like carbon films and highly hydrogenated amorphous carbon films of Examples 1-2 and Comparative Examples 1-3. A load of 5 N was applied in the friction experiment.

[0049] Figure 4 Surface microstructure images and roughness three-dimensional morphology images of the graphite-like carbon films of Examples 1-2 and Comparative Example 1. DETAILED DESCRIPTION

[0050] To make the purpose, technical solutions and advantages of this application more clear, the embodiments of this application will be described in detail below. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other in any way.

[0051] The present application is further described in detail below in conjunction with specific examples, but these examples should not be construed as limiting the present application.

[0052]

Tribological performance testing

[0053] Example 1 A graphite-like carbon film is prepared on a stainless steel substrate at a deposition bias of 30 V, comprising the following steps: 1) Using stainless steel as the deposition substrate, the substrate was polished and ultrasonically treated in alcohol and acetone solutions for 30 min, respectively. The alcohol solution was ultrasonically cleaned twice, and the acetone solution was ultrasonically cleaned twice. Finally, the substrate was dried for use. 2) Place the cleaned and dried substrate into the magnetron sputtering chamber and pump the vacuum to a vacuum degree of less than 8×10 -4 Pa, in an argon atmosphere, the substrate was bombarded with high-energy plasma for a primary cleaning, wherein the ion source current was 1.5 A, the chamber pressure was 2.5 Pa, and the cleaning time was 30 min; then a secondary cleaning was performed using a metal chromium target, wherein the chromium target current was 0.35 A, the chamber pressure was 2.5 Pa, and the cleaning time was 30 min; 3) Preparation of the enhancement layer: The inert sputtering gas source argon flow rate was controlled at 23 sccm. The chromium target was turned on to first deposit a Cr base layer at a working current of 6.7 A for 1 h. Then, two carbon targets and a chromium target were simultaneously turned on to prepare a Cr / C gradient transition layer. The chromium target current was 3.5 A, the carbon target current was 3 A, and the deposition time was 120 min. During the entire deposition process, the carbon target operating voltage was controlled at 550 V, and the chromium target operating voltage was controlled at 350 V. The bias voltage was controlled at 80 V during the entire enhancement layer deposition process. 4) Deposition of a chromium-doped graphite-like carbon working layer: The argon inlet of the sputtering inert gas source was controlled at 23 sccm and a deposition bias of 30 V. The chromium and carbon targets were simultaneously activated, with the carbon target operating at a voltage of 580 V and a current of 5.5 A; the chromium target voltage was 290 V and an operating current of 0.1 A. Maintaining other gas pressure conditions unchanged, the deposition was continued for 4 h to obtain a GLC film induced by a deposition bias of 30 V, i.e., a graphite-like carbon working layer.

[0054] In the graphite-like carbon film prepared in this embodiment, the total thickness of the reinforcement layer is 2 μm, the thickness of the graphite-like carbon working layer is 1.68 μm, the Cr doping amount is 2%, the hardness characteristic value is 13 GPa, the Young's modulus is 150 GPa, the critical load is 50 N, the roughness is 10 nm, and the sp 2 C / sp 3 The C ratio is 2.3.

[0055] The friction pair system of the graphite-like carbon film: The graphite-like carbon film prepared above was paired with a 6 mm diameter, highly hydrogenated nanoclustered carbon film dual ball. Friction tests were conducted using an Anton Paar tribometer under loads of 5-20 N, a frequency of 4 Hz, an amplitude of 4 mm, a nitrogen atmosphere, and room temperature conditions for 3000 friction cycles. The friction results showed that the graphite-like carbon film system had a friction coefficient of 0.003-0.008, achieving macroscopic superslip properties (see Appendix for details). Figure 1 ).

[0056] Example 2 A graphite-like carbon film is prepared on a stainless steel substrate with a deposition bias of 50 V, comprising the following steps: 1) Using stainless steel as the deposition substrate, the substrate was polished and ultrasonically treated in alcohol and acetone solutions for 30 min, respectively. The alcohol solution was ultrasonically cleaned twice, and the acetone solution was ultrasonically cleaned twice. Finally, the substrate was dried for use. 2) Place the cleaned and dried substrate sample into the magnetron sputtering chamber and evacuate the chamber to a vacuum degree of less than 1×10 - 4 Pa, and then in an argon atmosphere, the substrate was bombarded with high-energy plasma for a cleaning operation, wherein the ion source current was 1.5A, the pressure in the chamber was 2.5 Pa, and the cleaning time was 30 min; followed by a secondary cleaning operation using a metal chromium target, wherein the metal chromium target current was 0.35A, the pressure in the chamber was 2.5 Pa, and the cleaning time was 30 min; 3) Preparation of the enhancement layer: The inert sputtering gas source, argon, was controlled at a flow rate of 23 sccm. A chromium target was activated to first deposit a Cr base layer at a current of 6.7 A for 1 h. Subsequently, two carbon targets and a chromium target were simultaneously activated to deposit a Cr / C gradient transition layer. The chromium target current was 3.5 A, the carbon target current was 3 A, and the deposition time was 120 min. The carbon target operating voltage was controlled at 550 V and the chromium target operating voltage was controlled at 350 V throughout the deposition process. The bias voltage was controlled at 80 V throughout the entire enhancement layer deposition process. 4) Deposition of a chromium-doped graphite-like carbon working layer: The argon inert sputtering source gas flow rate was controlled to 23 sccm and the deposition bias was 50 V. The chromium and carbon targets were simultaneously turned on, with the carbon target operating at a voltage of 550 V and a current of 5.5 A; the chromium target voltage was 300 V and the operating current was 0.1 A. Maintaining other gas pressure conditions unchanged, the deposition was continued for 4 hours to obtain a GLC film induced by a 50 V deposition bias, i.e., a graphite-like carbon working layer.

[0057] In the graphite-like carbon film prepared in this embodiment, the total thickness of the reinforcement layer is 1.84 μm, the thickness of the graphite-like carbon working layer is 1.5 μm, the Cr doping amount is 1.00%, the hardness characteristic value is 17 GPa, the Young's modulus is 175 GPa, the critical load is 53 N, the roughness is 6 nm, and the sp 2 C / sp 3 The C ratio is 2.1.

[0058] The friction pair system of the graphite-like carbon film: The graphite-like carbon film prepared above was paired with a 6 mm diameter high-hydrogen nanoclustered carbon film dual ball. Friction tests were conducted using an Anton Paar tribometer under loads of 5-20 N, a frequency of 4 Hz, an amplitude of 4 mm, a nitrogen atmosphere, and room temperature conditions for 3000 friction cycles. The friction results showed that the graphite-like carbon film system had a friction coefficient of 0.009 at a load of 5 N, achieving macroscopic superslip properties, but rapidly failed under high loads, with a friction coefficient of 0.5 (see Appendix for details). Figure 2 ).

[0059] Comparative Example 1 A graphite-like carbon film is prepared on a stainless steel substrate at a deposition bias of 70 V, comprising the following steps: 1) Using stainless steel as the deposition substrate, the substrate was polished and ultrasonically treated in alcohol and acetone solutions for 30 min, respectively. The alcohol solution was ultrasonically cleaned twice, and the acetone solution was ultrasonically cleaned twice. Finally, the substrate was dried for use. 2) Place the cleaned and dried substrate sample into the magnetron sputtering chamber and evacuate the chamber to a vacuum degree of less than 1×10 - 4 Pa, and then in an argon atmosphere, the substrate was bombarded with high-energy plasma for a cleaning process, wherein the ion source current was 1.5 A and the pressure was 2.5 Pa for 30 min; followed by a secondary cleaning process using a metal chromium target, wherein the metal chromium target current was 0.35 A, the pressure was 2.5 Pa, and the cleaning time was 30 min; 3) Preparation of the enhancement layer: The argon flow rate of the sputtering inert gas source was controlled at 23 sccm. The chromium target was turned on to first deposit a Cr base layer at a working current of 6.7 A for 1 h. Then, two carbon targets and a chromium target were simultaneously turned on to prepare a Cr / C gradient transition layer. The chromium target current was 3.5 A, the carbon target current was 3 A, and the deposition time was 45 min. During the entire deposition process, the carbon target operating voltage was controlled at 550 V and the chromium target operating voltage was controlled at 350 V. The bias voltage was controlled at 90 V during the entire enhancement layer deposition process. 4) Deposition of a chromium-doped graphite-like carbon working layer: The argon inert sputtering source gas flow rate was controlled to 23 sccm and the deposition bias was 70 V. The chromium target and carbon target were simultaneously turned on, with the carbon target operating voltage at 500 V and the current at 4.50 A; the chromium target voltage was 350 V and the operating current at 0.20 A. Maintaining other gas pressure conditions unchanged, the deposition was continued for 6 h to obtain a GLC film induced by a 70 V deposition bias.

[0060] In the prepared graphite-like carbon film, the total thickness of the reinforcement layer is 1.74 μm, the thickness of the graphite-like carbon working layer is 1.42 μm, the Cr doping amount is 1.00%, the hardness characteristic value is 28 GPa, the Young's modulus is 250 GPa, the critical load is 56 N, the roughness is 7.8 nm, and the sp 2 C / sp 3 The C ratio is 1.6.

[0061] The friction pair system of the graphite-like carbon film: The graphite-like carbon film prepared above was paired with a 6 mm diameter high hydrogen nanoclustered carbon film dual ball. Friction tests were conducted using an Anton Paar tribometer at a load of 5 N, a frequency of 4 Hz, an amplitude of 4 mm, a nitrogen atmosphere, and room temperature. The friction results showed that the graphite-like carbon film system would fail quickly, with the friction coefficient rapidly increasing to 0.50, and could not achieve super-lubricity (see Appendix for details). Figure 3 ).

[0062] Comparative Example 2 A graphite-like carbon film is prepared on a stainless steel substrate with a deposition bias of 90 V, comprising the following steps: 1) Using stainless steel as the deposition substrate, the substrate was polished and ultrasonically treated in alcohol and acetone solutions for 30 min, respectively. The alcohol solution was ultrasonically cleaned twice, and the acetone solution was ultrasonically cleaned twice. Finally, the substrate was dried for use. 2) Place the cleaned and dried substrate sample into the magnetron sputtering chamber and evacuate the chamber to a vacuum degree of less than 1×10 - 4Pa, and then in an argon atmosphere, the substrate was bombarded with high-energy plasma for a cleaning process, wherein the ion source current was 1.5 A and the pressure was 2.5 Pa for 30 min; followed by a secondary cleaning process using a metal chromium target, wherein the metal chromium target current was 0.35 A, the pressure was 2.5 Pa, and the cleaning time was 30 min; 3) Preparation of the enhancement layer: The sputtering inert gas source argon flow rate was controlled at 23 sccm. The chromium target was first turned on to deposit the Cr base layer at a working current of 6.7 A for 1 h. Then, two carbon targets and a chromium target were simultaneously turned on to deposit the Cr / C gradient transition layer. The chromium target current was 3.5 A, the carbon target current was 3 A, and the deposition time was 45 min. During the entire deposition process, the carbon target operating voltage was controlled at 550 V, and the chromium target operating voltage was controlled at 350 V. The bias voltage was controlled at 80 V during the entire enhancement layer deposition process. 4) Deposition of a chromium-doped graphite-like carbon working layer: The argon inert sputtering source gas flow rate was controlled to 23 sccm and the deposition bias was 90 V. The chromium target and carbon target were simultaneously turned on, with the carbon target operating at a voltage of 500 V and a current of 4.50 A; the chromium target voltage was 350 V and the operating current was 0.20 A. Maintaining other gas pressure conditions unchanged, the deposition was continued for 6 hours to obtain a GLC film induced by a 90 V deposition bias.

[0063] In the prepared graphite-like carbon film, the total thickness of the reinforcement layer is 1.8 μm, the thickness of the graphite-like carbon working layer is 1.23 μm, the Cr doping amount is 2%, the hardness characteristic value is 29.6 GPa, the Young's modulus is 276 GPa, the critical load is 59.80 N, the roughness is 11 nm, and the sp 2 C / sp 3 The C ratio is 1.40.

[0064] The friction pair system of the graphite-like carbon film: The prepared graphite-like carbon film was paired with a 6 mm diameter high hydrogen nanoclustered carbon film dual ball. Friction tests were conducted using an Anton Paar tribometer at a load of 5 N, a frequency of 4 Hz, an amplitude of 4 mm, a nitrogen atmosphere, and room temperature. The friction results showed that the graphite-like carbon film system would fail quickly, with the friction coefficient rapidly rising to above 0.50, and could not achieve super-lubricity (see Appendix for details). Figure 3 ).

[0065] Comparative Example 3 A graphite-like carbon film is prepared on a stainless steel substrate with a deposition bias of 120 V, comprising the following steps: 1) Using stainless steel as the deposition substrate, the substrate was polished and ultrasonically treated in alcohol and acetone solutions for 30 min, respectively. The alcohol solution was ultrasonically cleaned twice, and the acetone solution was ultrasonically cleaned twice. Finally, the substrate was dried for use. 2) Place the cleaned and dried substrate sample into the magnetron sputtering chamber and evacuate the chamber to a vacuum degree of less than 1×10 - 4 Pa, and then in an argon atmosphere, the substrate was bombarded with high-energy plasma for a cleaning process, wherein the ion source current was 1.5A and the pressure was 2.5 Pa for 30 min; followed by a secondary cleaning process using a metal chromium target, wherein the metal chromium target current was 0.35A, the pressure was 2.5 Pa, and the cleaning time was 30 min; 3) Preparation of the enhancement layer: The sputtering inert gas source argon flow rate was controlled at 23 sccm. The chromium target was first turned on to deposit the Cr base layer at a working current of 6.7 A for 1 h. Then, two carbon targets and a chromium target were simultaneously turned on to deposit the Cr / C gradient transition layer. The chromium target current was 3.5 A, the carbon target current was 3 A, and the deposition time was 45 min. During the entire deposition process, the carbon target operating voltage was controlled at 550 V, and the chromium target operating voltage was controlled at 350 V. The bias voltage was controlled at 80 V during the entire enhancement layer deposition process. 4) Deposition of a chromium-doped graphite-like carbon working layer: The argon inert sputtering source gas flow rate was controlled to 23 sccm and the deposition bias was 120 V. The chromium target and carbon target were simultaneously turned on, with the carbon target operating voltage at 500 V and current at 4.5 A; the chromium target voltage was 350 V and operating current at 0.20 A. Maintaining other gas pressure conditions unchanged, the deposition was continued for 6 h to obtain a GLC film induced by a 120 V deposition bias.

[0066] In the prepared graphite-like carbon film, the total thickness of the reinforcement layer is 1.76 μm, the thickness of the graphite-like carbon working layer is 1.13 μm, the Cr doping amount is 4%, the hardness characteristic value is 32 GPa, the Young's modulus is 348 GPa, the critical load is 64.8 N, the roughness is 12.1 nm, and the sp 2 C / sp 3 The C ratio is 1.1.

[0067] The friction pair system of the graphite-like carbon film: The prepared graphite-like carbon film was paired with a 6 mm diameter high hydrogen nanoclustered carbon film dual ball. Friction tests were conducted using an Anton Paar tribometer at room temperature under load of 5 N, frequency of 4 Hz, amplitude of 4 mm, nitrogen atmosphere, and friction results showed that the graphite-like carbon film system would fail quickly, with the friction coefficient rapidly increasing to 0.6, and could not achieve super-lubricity (see Appendix for details). Figure 3 ).

[0068] In addition, according to Figure 4 The surface microstructure and roughness 3D topography images of the graphite-like carbon films obtained in Examples 1-2 and Comparative Example 1 clearly show that as the working layer deposition bias increases, the internal structure of the film's working layer gradually transitions from an amorphous, disordered structure to an ordered structure growing perpendicular to the interface, with a corresponding increase in roughness. The microstructures of Comparative Examples 2-3 are similar to that of Comparative Example 1, differing only in that the degree of ordering increases.

[0069] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

[0070] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A graphite-like carbon film, wherein the graphite-like carbon film is a hydrogen-free graphite-like carbon film, comprising a reinforcing layer located on a substrate surface and a graphite-like carbon working layer located on the reinforcing layer, wherein the reinforcing layer comprises a Cr primer layer located on the substrate surface and a Cr / C gradient transition layer located on the Cr primer layer; the graphite-like carbon working layer is doped with metallic Cr, wherein the doping amount of metallic Cr is 0.5% to 5% in atomic percentage; and the graphite-like carbon film, sp 2 C / sp 3 The C ratio is 1.8-4.

0.

2. The graphite-like carbon film according to claim 1, wherein The thickness of the reinforcement layer is 1.0-2.0 μm; and / or The thickness of the graphite-like carbon working layer is 1.0-4.0 μm; and / or The graphite-like carbon film has a characteristic hardness of 10 -25 GPa; and / or The Young's modulus of the graphite-like carbon film is 100-200 GPa; and / or The critical load of the graphite-like carbon film is 40 N-55 N; and / or The surface roughness of the graphite-like carbon film is 1 nm-10 nm.

3. The graphite-like carbon film according to claim 1 or 2, wherein: The substrate is selected from a single crystal silicon wafer or a sheet / spherical metal; Optionally, the sheet / spherical metal is selected from any one of quenched GCr15 bearing steel, high temperature alloy, stainless steel, titanium alloy, and high entropy alloy.

4. A method for preparing the graphite-like carbon film according to any one of claims 1 to 3, comprising the following steps: 1) Surface pretreatment of the substrate, including polishing the substrate to mirror-grade smoothness, followed by ultrasonic cleaning and high-energy ion beam / particle beam cleaning under high vacuum; 2) preparing an enhancement layer, comprising: controlling the flow rate of argon gas, a sputtering inert gas source, to 5-30 sccm, starting a metal chromium target, controlling a deposition current to 4-7.5 A, and a deposition time to 30-120 minutes; then simultaneously starting a non-metallic carbon target and a metal chromium target to prepare a Cr / C gradient transition layer, wherein the deposition current of the metal chromium target is 3-4 A, and the deposition current of the non-metallic carbon target is 2.5-3.5 A, and the deposition time is 30-240 minutes; 3) Preparation of a chromium-doped graphite-like carbon working layer, comprising: controlling the flow rate of argon as a sputtering inert gas source to 5-30 sccm and a deposition bias voltage to 15-50 V; simultaneously turning on a metal chromium target and a non-metallic carbon target, with the operating voltage of the non-metallic carbon target being 250-650 V and the operating current being 0.5-7.6 A; and the operating voltage of the metal Cr target being 50-350 V and the operating current being 0.1-0.9 A; maintaining other gas pressure conditions unchanged, and depositing for 2-8 hours to obtain the graphite-like carbon working layer.

5. The method according to claim 4, wherein In step 1), the ultrasonic cleaning step includes: wiping the polished substrate surface with alcohol and acetone, and then placing it in alcohol and acetone solutions for ultrasonic treatment for 10-30 minutes respectively; wherein the alcohol cleaning number is 1-2 times, the acetone cleaning number is greater than 2 times, and then quickly drying for use.

6. The method according to claim 4 or 5, wherein: In step 1), the high-energy ion beam / particle beam cleaning under high vacuum comprises: placing the cleaned and dried substrate into a rotating rack in a coating chamber, and evacuating the vacuum to less than 5×10 -3 Pa, introduce inert gas argon, load the high energy ion source for primary cleaning, and then use the metal chromium target for secondary cleaning; Optionally, when the high energy ion source is loaded for one cleaning, the ion source current is 1-5 A, the cleaning time is 20-40 min, and the pressure in the chamber is 1-3 Pa; Optionally, when a metal chromium target is used for secondary cleaning, the chromium target current is 3-4 A, the cleaning time is 20-40 min, and the pressure in the chamber is 1-3 Pa.

7. The method according to claim 4 or 5, wherein: In step 2), the bias voltage is controlled at 70-150 V during the entire enhancement layer deposition process; and / or In step 3), the deposition bias is 25-50 V.

8. A graphite-like carbon film prepared by the method according to any one of claims 4 to 7.

9. A friction pair, comprising the dual spheres of the graphite-like carbon film and the high-hydrogen-containing amorphous carbon film according to any one of claims 1 to 3 and 8.

10. A method for achieving super-slippery properties using the graphite-like carbon film according to any one of claims 1 to 3 and 8, the method comprising: The graphite-like carbon film and the high-hydrogen-content amorphous carbon film dual ball are formed into a friction pair to achieve super-lubricity in a nitrogen atmosphere.

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