Ultrasonic enhanced tribochemical catalysis film forming method

Abstract

The invention discloses an ultrasonic enhanced friction chemical catalysis film forming method, discloses a grinding agent used in the method, a carbon-based thin film and a film forming device, and relates to the technical field of carbon-based thin film preparation and processing. The film forming method comprises the steps that a grinding agent containing palladium nano-particles and a carbon precursor solution is prepared, ultrasonic vibration auxiliary grinding is conducted on the surface of a workpiece to be coated, the grinding agent containing the palladium nano-particles and the carbon precursor solution prepared in the step S1 is adopted in the grinding process, and grinding lasts for a certain period of time. According to the method, palladium nanoparticles are used as a catalyst for ultrasonic enhanced friction chemistry, dehydrogenation chain scission of carbon precursor molecules by the palladium nanoparticle catalyst is driven by high pressure, flash temperature and shear stress brought by ultrasonic cavitation and grinding, and the carbon precursor molecules are recombined and deposited on the grinding surface of stainless steel to form an amorphous carbon-based friction film in situ; the ultrasonic enhanced tribochemical catalytic film forming method provides a new way for industrial film preparation.

Description

Technical Field

[0001] The present invention relates to the technical fields of advanced inorganic non-metallic materials, electronic devices, and more particularly to technologies or products such as graphite materials, hard carbon materials, carbon products, and carbon-based films, which are widely used in aerospace, flexible electronic devices, and other fields. The present invention particularly relates to an ultrasonically enhanced tribochemical catalytic film-forming method for preparing carbon-based films. Background Art

[0002] Carbon-based films can contain pure carbon or other elements (such as H, Cr, N, Al, etc.) to impart specific physical and chemical properties. Examples include diamond-like carbon films, porous graphene films, and chromium-aluminum co-doped carbon films. These films have excellent wear resistance and self-lubricating properties and are often used to improve the tribological properties of moving parts. The challenge of preparing carbon-based films in a low-cost, green, simple, and efficient manner under conventional conditions is a hot topic of ongoing exploration in industrial film-making technology.

[0003] In the existing membrane making technology, a method for preparing a porous graphene film and its processing device (publication number CN118666275A) applied by Guangdong University of Technology discloses a method for preparing a porous graphene film. Through a first laser beam, a second laser beam, a third laser beam, and a Joule heating device, the activator is uniformly coated on the flexible substrate, the activator and the carbon material are fully and uniformly mixed, the activator and the carbon material are fully reacted, and the formation of a graphene micro-nano porous structure is promoted. Finally, a specific surface area of ​​1400 to 2000 m 2 Although this membrane-forming technology can produce graphene films with large specific surface area and excellent flexibility, its reaction conditions and subsequent processing are complex, requiring more processing equipment and high temperature treatment.

[0004] Lanzhou University of Technology has also applied for a method for regulating the friction coefficient of carbon-based films by friction-induced sliding interface reconstruction (publication number CN119392200A). The method discloses a method for constructing carbon-based films by friction-induced interface reconstruction. The first sputtering and the second sputtering are completed using unbalanced magnetron sputtering technology, respectively realizing the deposition of a transition metal bonding layer and the deposition of a transition metal carbide-reinforced carbon-based film. Finally, a friction test is carried out on the carbon-based film using a friction and wear device to achieve the regulation of the carbon-based film.

[0005] Anhui Yalan Sealing Co., Ltd. has also applied for a wear-resistant carbon-based composite film for aerospace seals and its preparation method (publication number CN117070893A). A method for preparing a wear-resistant carbon-based composite film for aerospace seals is disclosed. A Ti / SiC transition layer, a MoS2 / SiC transition layer and a MoS2 / sp are deposited by magnetron sputtering. 3-C transition layer, utilizing the reinforcing properties of SiC ceramic phase and the self-lubricating property of MoS2, improves the film-base bonding strength and enhances the toughness and load-bearing capacity of carbon-based composite film.

[0006] Among the above existing technologies, the film-making technology disclosed in CN119392200A can construct a carbon-based film with excellent self-lubricating properties and can realize the regulation of the friction coefficient of the carbon-based film, and the film-making technology disclosed in CN117070893A can construct a composite carbon-based film with toughness and load-bearing capacity, but both technologies rely on a vacuum environment, expensive equipment, low sputtering rate, and many consumables.

[0007] To this end, there is an urgent need to break through new technologies for the high-efficiency, mass-produced preparation of carbon-based films at room temperature and pressure. Summary of the Invention

[0008] The purpose of the present invention is to provide an ultrasonically enhanced tribochemical catalytic film formation method, which solves the problem of low carbon-based film formation rate by enhancing the tribochemical catalytic reaction rate or opening up new reaction channels through the high pressure and flash temperature caused by the ultrasonic cavitation effect. At the same time, the process of the present invention is simple, requires less materials, and can also produce carbon-based films under conventional conditions, solving the problems of high cost and harsh environment of film formation technology.

[0009] According to the first main aspect of the present invention, there is provided an ultrasonically enhanced tribochemical catalytic film forming method comprising the following two steps: S1, preparing abrasive containing palladium nanoparticles and carbon precursor solution; S2, performing ultrasonic vibration-assisted grinding on the surface of the workpiece to be coated, using the grinding agent containing palladium nanoparticles and carbon precursor solution prepared in step S1, and continuing the grinding for a certain period of time.

[0010] In the above scheme, the present invention uses palladium nanoparticles as a catalyst and n-hexane as a carbon precursor. Under the action of high pressure, flash temperature and grinding shear stress generated by the ultrasonic cavitation effect, the carbon precursor molecules are driven to dehydrogenate and break the chain. After catalytic recombination, they are deposited on the surface of the workpiece to form a carbon-based film, breaking through the traditional technology's dependence on vacuum or high temperature.

[0011] Furthermore, the present invention achieves efficient catalytic film formation by designing an abrasive composition containing palladium nanoparticles in a specific ratio. 5% to 10% by weight of palladium nanoparticles serve as catalytic active centers, while n-hexane serves as both a carbon source and a dispersion medium. Ultrasonic dispersion ensures uniform distribution of the palladium nanoparticles, forming a stable catalytic system. During the abrading process, ultrasound-assisted palladium nanoparticles fully contact the carbon precursor, reducing the activation energy of the reaction and promoting tribochemical film formation.

[0012] In comparison, most existing solutions rely on vacuum environment or high energy input, while the present invention achieves film formation at room temperature and pressure through the synergistic effects of ultrasound, friction and catalysis, breaking through the bottleneck of expensive equipment and complex processes.

[0013] In some embodiments, as a preferred solution, the abrasive containing palladium nanoparticles and carbon precursor solution is prepared by adding palladium nanoparticles to a n-hexane solution at room temperature and performing ultrasonic dispersion.

[0014] In the above scheme, the present invention ultrasonically disperses palladium nanoparticles in n-hexane at room temperature, using the shear force of ultrasonic cavitation to break up particle agglomerations and form a uniform catalytic system; n-hexane serves as both a carbon precursor and a dispersion medium, ensuring full contact between the palladium nanoparticles and the carbon source during grinding, thereby reducing the reaction activation energy.

[0015] While existing technologies mostly use solid or gaseous carbon sources, which require a complex activation process, the present invention uses liquid n-hexane as a carbon precursor and achieves efficient activation of the catalyst through ultrasonic dispersion, without the need for additional activators or high-temperature treatment.

[0016] In some embodiments, as a preferred solution, the ultrasonic vibration-assisted grinding is to form a friction pair between the workpiece to be coated and a cubic boron nitride grinding wheel, apply ultrasonic vibration during the grinding process, and use the abrasive containing palladium nanoparticles and carbon precursor solution for grinding to form a carbon-based film on the surface of the workpiece.

[0017] In the above scheme, the present invention uses a cubic boron nitride grinding wheel and a workpiece to form a friction pair, applies longitudinal high-frequency vibration through ultrasonic vibration, generates alternating stress at the grinding interface, and cooperates with the catalytic effect of palladium nanoparticles to decompose n-hexane into carbon free radicals driven by frictional heat and cavitation energy, which are then deposited as a thin film.

[0018] While existing technologies usually rely on magnetron sputtering to deposit a transition layer, which requires a vacuum chamber, the present invention directly triggers a tribochemical reaction through a friction pair and ultrasound, eliminating the need for a prefabricated transition layer and making the film-forming process more efficient.

[0019] In some embodiments, as a preferred solution, the ultrasonic dispersion time is 5 to 15 minutes and the temperature is 20 to 30°C.

[0020] The present invention limits the ultrasonic dispersion time to 5 to 15 minutes and the temperature to 20 to 30°C. It achieves nanoscale dispersion of palladium nanoparticles at an appropriate energy level through cavitation, avoiding particle agglomeration or hexane volatilization caused by prolonged ultrasonication, ensuring full exposure of the catalyst's active sites. By quantifying ultrasonic parameters, the present invention achieves uniform dispersion of the catalyst, improving dispersion efficiency by over 30% compared to existing technologies.

[0021] In some embodiments, as a preferred solution, the output power of the ultrasonic vibration in the ultrasonic vibration-assisted grinding is 100-300 W, and the grinding time is 15-60 min.

[0022] The present invention selects a parameter combination of ultrasonic power of 100 to 300 W, grinding time of 15 to 60 minutes, and rotation speed of 200 to 500 r / min to ensure the energy matching of cavitation effect and friction shear force: too low power cannot induce sufficient cavitation, while too high power causes overheating and decomposition of the film; the rotation speed and time synergistically control the carbon source deposition rate to form a uniform film of 50 to 100 nm.

[0023] According to the second main aspect of the present invention, there is provided an abrasive for ultrasonic tribochemical film formation in the aforementioned method, the abrasive being made from the following raw material components: Palladium nanoparticles, accounting for 5% to 10% by mass; n-Hexane solution, serving as carbon precursor and dispersion medium; The palladium nanoparticles are ultrasonically dispersed in n-hexane to form a uniform system.

[0024] In the above scheme, the present invention uses ultrasonic dispersion to uniformly suspend 5% to 10% by weight of palladium nanoparticles in n-hexane, forming a stable catalytic system. The palladium nanoparticles act as active centers. Under the local high temperature and pressure generated by ultrasonic cavitation, they adsorb and activate n-hexane molecules, lowering the C-H bond breakage energy barrier and promoting the generation of carbon free radicals. The n-hexane acts as both a carbon source and a solvent, ensuring uniform distribution of the catalyst at the grinding interface.

[0025] In comparison, most existing technologies use solid target materials or gaseous carbon sources, which require a vacuum environment and high-energy particle bombardment. The present invention adopts a liquid catalytic system and realizes in-situ activation of the catalyst through ultrasonic dispersion at room temperature and pressure, which simplifies the process and significantly improves material utilization.

[0026] In some embodiments, as a preferred solution, the particle size of the palladium nanoparticles is 5 to 20 nm, and the concentration of the carbon precursor in the n-hexane solution is 0.1 to 1 mol / L.

[0027] In the above scheme, the present invention selects palladium nanoparticles with a particle size of 5-20 nm to provide a high specific surface area (approximately 50-100 m² / g) and numerous active sites, enhancing the adsorption and catalytic capacity for n-hexane molecules. A carbon precursor concentration of 0.1-1 mol / L ensures sufficient carbon source supply while avoiding excessive concentrations that could lead to particle agglomeration or film defects. The nanoscale catalyst size and optimal concentration synergistically control the film formation rate and quality.

[0028] According to the third main aspect of the present invention, a carbon-based film prepared by the above method is provided, wherein the carbon-based film is attached to the surface of the metal substrate and has a thickness of 50 to 100 nm; the carbon-based film has an amorphous structure, and the Raman spectrum of the carbon-based film is 1 D / I G The value is 1.5 to 1.8, and the sp²-C phase content accounts for ≥60%; Furthermore, palladium nanoparticles are uniformly embedded in the carbon-based film.

[0029] In the above scheme, the present invention uses ultrasonic friction catalysis to decompose the carbon precursor to form an amorphous carbon structure. D / I G A value of 1.5 to 1.8 indicates moderate sp² hybridization, providing good lubricity. An sp²-C phase of ≥60% ensures film toughness. Uniformly embedded palladium nanoparticles (5-20 nm in diameter) enhance film-substrate adhesion through a pinning effect and inhibit crack propagation. A thickness of 50-100 nm balances wear resistance and internal stress, preventing thick film shedding.

[0030] In some embodiments, as a preferred solution, the metal substrate is stainless steel, titanium alloy or aluminum alloy.

[0031] In another aspect of this technology, the natural oxide layers (such as Al2O3 and TiO2) on the surfaces of stainless steel, titanium alloys, and aluminum alloys are micro-fractured under ultrasonic vibration, exposing the fresh metal surface, which then forms metal-carbon chemical bonds (such as Fe-C and Ti-C) with carbon free radicals. This invention uses palladium nanoparticles to catalyze the carbon source to form a transition layer at the interface, further enhancing the bonding strength. This invention uses ultrasound to induce an interfacial reaction, directly forming a strong bonding film in situ on the metal substrate, simplifying the process and reducing costs.

[0032] According to a fourth main aspect of the present invention, there is provided an ultrasonically enhanced tribochemical film forming device for implementing the method described in the claims, comprising one or a combination of the following systems: Grinding system: includes cubic boron nitride grinding wheel and workpiece clamping mechanism; Ultrasonic vibration system: used to apply longitudinal ultrasonic vibration with a frequency of 20 to 40 kHz to the grinding interface; Abrasive supply system: used to deliver n-hexane solution containing palladium nanoparticles; Control system: used to adjust ultrasonic power, grinding speed and processing time.

[0033] In the above scheme, the grinding system provides mechanical shear force, and the ultrasonic vibration system produces cavitation effect through 20-40kHz longitudinal vibration, forming high pressure and microjets at the grinding interface, accelerating the mass transfer of catalyst and carbon source; the abrasive supply system continuously replenishes active ingredients, and the control system accurately matches ultrasonic power, speed and time to achieve efficient energy utilization.

[0034] The grinding system is the core execution unit of the device, mainly composed of a cubic boron nitride (CBN) grinding wheel, a workpiece clamping mechanism, and a spindle drive motor. The selected CBN grinding wheel must have a hardness of at least 2500 to 3000 HV and is fixed to the output end of the spindle motor via a flange, enabling speed adjustment. The workpiece clamping mechanism generally includes a three-dimensional mobile platform, which is bolted to the workbench. It can accurately position the workpiece to be coated and form a friction pair with the grinding wheel. The distance between the two is adjusted by a servo motor to ensure uniform distribution of grinding pressure, providing the mechanical shear force foundation for tribochemical film formation.

[0035] The ultrasonic vibration system achieves energy conversion and transmission through a piezoelectric transducer, a horn, and an ultrasonic power supply. The piezoelectric transducer, stimulated by a 20-40 kHz electrical signal, generates high-frequency mechanical vibrations. After being amplified by the horn, these vibrations are transmitted to the workpiece clamping mechanism via a rigid fixture, generating longitudinal ultrasonic vibrations on the workpiece surface. The ultrasonic power supply output power is adjustable between 100 and 300 W. The resulting cavitation effect generates localized high pressures of hundreds of MPa and flash temperatures of thousands of Kelvin at the grinding interface, providing energy for the catalytic reaction of the carbon precursor.

[0036] The abrasive supply system uses corrosion-resistant piping to connect the reservoir, peristaltic pump, and atomizing nozzle. The reservoir stores a hexane solution containing 5% to 10% palladium nanoparticles. The peristaltic pump delivers this solution to the atomizing nozzle at a flow rate of 0.1 to 1 mL / min. The nozzle is aimed at the friction interface between the grinding wheel and the workpiece, ensuring that the abrasive mist evenly covers the grinding area. This design ensures a continuous supply of palladium nanoparticle catalyst while also removing grinding heat through the volatilization of the hexane, maintaining a stable reaction environment.

[0037] The control system is centered around a PLC (such as a Siemens S7-200), connected via RS485 communication cables to the ultrasonic power supply, spindle motor, peristaltic pump, and sensor assembly. These sensors monitor ultrasonic power, grinding wheel speed, and grinding interface temperature in real time. The ultrasonic power sensor provides feedback on cavitation energy, a speed encoder monitors the grinding rate, and a temperature sensor prevents interface overheating. A touchscreen human-machine interface can also be designed for parameter setting. The PLC dynamically adjusts various actuators based on this feedback, achieving closed-loop control of the film-forming process.

[0038] When the device is working, the workpiece is first fixed to the clamping mechanism and adjusted to the position directly below the grinding wheel through the three-dimensional platform. The spindle motor is started to rotate the grinding wheel. At the same time, the ultrasonic power supply drives the transducer to generate vibration, which is transmitted to the surface of the workpiece through the amplitude transformer. The peristaltic pump delivers the abrasive to the friction interface. Under the synergistic effect of grinding wheel grinding and ultrasonic cavitation, n-hexane is dehydrogenated and chain-broken under the catalysis of palladium nanoparticles, and carbon free radicals are deposited to form an amorphous carbon-based film of 50 to 100 nm. The control system monitors the parameters in real time. When the interface temperature exceeds 30°C or the ultrasonic power fluctuation exceeds ±5%, the speed or power is automatically adjusted to ensure the uniformity of film formation and bonding strength. The entire process does not require a vacuum environment, and efficient film formation can be completed at normal temperature and pressure.

[0039] In summary, compared with the existing technology, the film-forming method of the present invention utilizes the high pressure, flash temperature and shear force during grinding caused by the cavitation effect generated by the high-frequency vibration of ultrasound to drive palladium nanoparticles to catalyze the carbon precursor molecules to undergo a large amount of dehydrogenation and chain breaking in a short period of time. The free radicals and palladium nanoparticles are recombined and deposited on the friction surface to form a carbon-based friction film, thereby solving the problem of relying on special conditions such as carbon plasma and vacuum and slow film-forming rate in the preparation of carbon-based films.

[0040] Moreover, the film-making method of the present invention does not require harsh conditions such as vacuum and high temperature and the regulation of complex parameters, and has the advantages of simple process and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A TEM image of a cross section of a carbon-based film in a wear scar after 30 minutes of ultrasonic grinding according to an embodiment of the present invention is shown; Figure 2 A high-resolution TEM image of a carbon-based tribofilm after 30 minutes of ultrasonic grinding according to an embodiment of the present invention is shown; Figure 3 The Raman spectrum of the carbon-based tribofilm after 30 minutes of ultrasonic grinding treatment and the Raman spectrum outside the wear scar of the carbon-based tribofilm in one embodiment of the present invention is shown in the comparison diagram; Figure 4 The Raman spectrum outside the wear scar is shown in a comparison diagram of Raman spectra of a carbon-based tribofilm and outside the wear scar after 30 minutes of ultrasonic grinding in one embodiment of the present invention. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention will be described in detail below so that the purpose, features and advantages of the present invention can be more clearly understood. It should be understood that the following embodiments are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0043] In the following description, for the purpose of illustrating the various disclosed embodiments, certain specific details are set forth in order to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the relevant art will recognize that the embodiments may be practiced without one or more of these specific details. In other cases, well-known techniques associated with this application may not be shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0044] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any manner in one or more embodiments.

[0045] Example 1:

[0046] An ultrasonically enhanced tribochemical catalytic film forming method comprises the following two steps: S1: Prepare a lubricant containing palladium nanoparticles (5%wt): At room temperature, palladium nanoparticles are added to a n-hexane solution, and ultrasonic dispersion is performed to prepare a solution containing 5%wt palladium nanoparticles and n-hexane carbon precursor, which is used as an abrasive for ultrasonic vibration-assisted grinding.

[0047] S2: Ultrasonic Vibration-Assisted Grinding: Prior to the tribocatalytic treatment, 304 stainless steel was ultrasonically cleaned with deionized water and anhydrous ethanol for 5 minutes each to remove surface impurities. The 304 stainless steel and a cubic boron nitride grinding wheel formed a friction pair. The palladium-containing nanoparticles prepared in step S1 and the n-hexane carbon precursor solution served as the abrasive. During the grinding process, the workpiece to be filmed and the grinding wheel were subjected to relative motion while ultrasonic vibrations were applied.

[0048] The ultrasonic vibration-assisted grinding conditions are as follows: at room temperature, the ultrasonic frequency is 20 kHz, the ultrasonic power output power is 200 W, the direction is longitudinal, the grinding wheel speed is 300 r / min, and the processing time is 30 min.

[0049] Figures 1-4 The comparison of the process effects of the above embodiments is shown.

[0050] in, Figure 1 This is a TEM image of the inner cross section of the wear scar on the friction surface in the embodiment of the present invention. Figure 2 This is a high-resolution TEM image of the carbon-based tribofilm in an embodiment of the present invention.

[0051] Depend on Figure 1It can be seen that a carbon-based film is formed on the surface of the 304 stainless steel substrate after ultrasonic friction catalysis. The thickness of the carbon-based film is about 72 nm. The film is uniform, dense and continuously distributed, and there is no membrane-based separation phenomenon.

[0052] Depend on Figure 2 It can be seen that the film is an amorphous carbon-based film, which is bonded to the substrate and has good film-substrate bonding.

[0053] Figure 3 is a Raman spectrum of the carbon-based film in an embodiment of the present invention, Figure 4 This is a Raman spectrum diagram outside the wear scar in the embodiment of the present invention.

[0054] Depend on Figure 3 It can be seen that the carbon-based film has obvious D peak and G peak, and I D / I G The value is 1.69, and the amorphous carbon-based film sp 2 -The C phase content is higher and the lubrication performance is better.

[0055] Depend on Figure 4 It can be seen that there are no obvious D peaks and G peaks outside the wear scar, and no DLC-like carbon film structure is formed.

[0056] The technical terms, technical principles or technical means related to the technical solutions of the present invention involved in the above embodiments, which are not described in detail in the above content, are all well-known technologies or customary means mastered by those skilled in the art.

[0057] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. An ultrasonic enhanced tribochemical catalytic film forming method, characterized in that: It includes the following 2 steps: S1, preparing abrasive containing palladium nanoparticles and carbon precursor solution; S2, performing ultrasonic vibration-assisted grinding on the surface of the workpiece to be coated, using the grinding agent containing palladium nanoparticles and carbon precursor solution prepared in step S1, and continuing the grinding for a certain period of time.

2. The ultrasonic enhanced tribochemical catalytic film forming method according to claim 1, characterized in that: The abrasive containing palladium nanoparticles and carbon precursor solution is prepared by adding palladium nanoparticles into a normal hexane solution at room temperature and performing ultrasonic dispersion.

3. The ultrasonic enhanced tribochemical catalytic film forming method according to claim 1 or 2, characterized in that: The ultrasonic vibration assisted grinding is to form a friction pair between the workpiece to be coated and the cubic boron nitride grinding wheel, apply ultrasonic vibration during the grinding process, and use the grinding agent containing palladium nanoparticles and carbon precursor solution to grind and form a carbon-based film on the surface of the workpiece.

4. The ultrasonic enhanced tribochemical catalytic film forming method according to claim 2, characterized in that: The ultrasonic dispersion time is 5 to 15 minutes, and the temperature is 20 to 30°C.

5. The ultrasonic enhanced tribochemical catalytic film forming method according to claim 3, characterized in that: The output power of the ultrasonic vibration in the ultrasonic vibration-assisted grinding is 100 to 300 W, and the grinding time is 15 to 60 minutes.

6. An abrasive for ultrasonic tribochemical film formation according to the method of claim 1, characterized in that: Made from the following raw materials: Palladium nanoparticles, accounting for 5% to 10% by mass; n-Hexane solution, serving as carbon precursor and dispersion medium; The palladium nanoparticles are ultrasonically dispersed in n-hexane to form a uniform system.

7. The abrasive for ultrasonic tribochemical film formation according to claim 6, characterized in that: The particle size of the palladium nanoparticles is 5 to 20 nm, and the concentration of the carbon precursor in the n-hexane solution is 0.1 to 1 mol / L.

8. A carbon-based film prepared by the method of claim 1, characterized in that: The carbon-based film is attached to the surface of the metal substrate and has a thickness of 50 to 100 nm. The carbon-based film has an amorphous structure and the Raman spectrum shows I D / I G The value is 1.5 to 1.8, and the sp²-C phase content accounts for ≥60%; Furthermore, palladium nanoparticles are uniformly embedded in the carbon-based film.

9. The carbon-based film according to claim 8, characterized in that The metal matrix is ​​stainless steel, titanium alloy or aluminum alloy.

10. An ultrasonic enhanced tribochemical film forming device for implementing the method described in claim 1, characterized in that: Includes one or a combination of the following systems: Grinding system: includes cubic boron nitride grinding wheel and workpiece clamping mechanism; Ultrasonic vibration system: used to apply longitudinal ultrasonic vibration with a frequency of 20 to 40 kHz to the grinding interface; Abrasive supply system: used to deliver n-hexane solution containing palladium nanoparticles; Control system: used to adjust ultrasonic power, grinding speed and processing time.

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