Nanofluid-assisted laser texturing DLC / Cr / TiAlN composite coating and preparation method thereof

Abstract

The invention belongs to the technical field of composite coatings, and particularly relates to a nanofluid-assisted laser texturing DLC / Cr / TiAlN composite coating and a preparation method thereof. According to the invention, through sputtering target material particle layer growth, a micron-scale three-layer functional gradient coating is formed through co-growth, and a TiAlN gradient structure with high hardness, low residual stress and high bonding strength is used as a supporting layer; a Cr coating with high toughness, crack propagation resistance and low coating internal stress is introduced as an interface layer; and a DLC coating with a self-lubricating function is used as a functional top layer. A hard-tough-hard three-layer composite structure is formed by adopting a TiAlN coating, a Cr coating and a DLC coating, and surface texturing treatment is performed on the TiAlN coating through a nanofluid-assisted laser processing technology, so that the hardness of the TiAlN coating and the film-substrate bonding force are improved, and the interface bonding strength of the DLC / Cr / TiAlN composite coating is optimized.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite coatings, and in particular relates to a nanofluid-assisted laser-textured DLC / Cr / TiAlN composite coating and a preparation method thereof. Background Art

[0002] Dry machining technology has emerged due to its significant environmental and sustainable development advantages. In recent years, it has attracted widespread attention and discussion in both domestic and international industrial and academic research circles. 316 stainless steel, due to its excellent plasticity, corrosion resistance, excellent hydrogen damage resistance, and mature production process, has become an important material in high-end manufacturing fields such as marine transportation, biomedicine, and aerospace. However, the high hardness, low thermal conductivity, and work-hardening properties of 316 stainless steel cause severe wear on the tool during machining. Furthermore, due to the lack of cooling and lubrication from the coolant, high cutting temperatures are generated during dry cutting, increasing the friction coefficient between the tool surface and the workpiece, which in turn accelerates tool wear and shortens tool life.

[0003] Physical Vapor Deposition (PVD), as the core surface engineering technology of modern manufacturing, has important application value in the industrial field. The TiAlN coating system prepared by this technology has become a representative solution for surface strengthening of cutting tools and wear-resistant parts. Its performance advantage comes from the fact that the introduction of Al elements prompts the coating to spontaneously form a nano-scale Al2O3 oxide film under high-temperature conditions. This film is both chemically inert and thermally stable, and can maintain high hardness on the surface of the material. In addition, the strong covalent bonds formed between Al atoms and N atoms also significantly improve the hardness, thermal stability and oxidation resistance of the TiAlN coating. The hardness, thermal stability and oxidation resistance of the coating increase with the increase of Al content. However, the friction coefficient of the coating of traditional TiAlN coated tools is large under dry cutting, which causes a high temperature between the friction pairs and eventually leads to severe coating wear.

[0004] At present, researchers have used various methods to improve the surface and interface properties of TiAlN-based coated tools, mainly focusing on substrate pretreatment, composition optimization and structural design.

[0005] (1) Substrate pretreatment

[0006] The pretreatment of the tool substrate in TiAlN-based PVD-coated tools has been shown to be a significant factor influencing coating performance. This is due to the significant differences in crystal structure parameters (including lattice type and lattice constant) between the coating and substrate materials. Furthermore, the coating deposition process requires key stages such as heterogeneous nucleation and epitaxial growth. Therefore, the final microstructure and service performance of the coating are influenced by a combination of various substrate properties, including the intrinsic properties of the substrate material, the distribution of residual stresses, the surface morphology, and the chemical composition. However, traditional pretreatment methods (such as sandblasting and acid etching) have the disadvantages of insufficient environmental protection measures and poor preparation repeatability. High-energy particle beam methods (such as plasma etching and laser irradiation) also produce irregular surface roughness and poor repeatability.

[0007] (2) Ingredient optimization

[0008] By adding a fourth element to TiAlN coatings, the coating's oxidation resistance and thermal stability can be further improved, thereby ensuring mechanical and tribological properties under harsh machining environments. For example, Zhang et al. deposited a Ti0.5Al0.4Si0.1N coating on a Ti48Al2Cr2Nb alloy using arc ion plating, adding Si. A Ti0.5Al0.5N coating was also deposited for comparison. The results showed that the TiAlSiN coating exhibited excellent cyclic oxidation resistance at 900°C, primarily due to Si promoting the selective oxidation of Al and forming a continuous Al2O3 top layer within the oxide layer. A. Hemmati et al. found that the addition of Ta delayed crater wear and subsequent substrate exposure in TiAlN-coated tools, attributing this to the improved metal flowability of the chip underside due to the protective tribo-oxide layer (Al2O3) formed on the friction surface. Furthermore, a low recrystallization fraction was observed in EBSD images of chip cross-sections, indicating reduced heat transfer and plastic deformation. However, most of these added elements are difficult and expensive to obtain.

[0009] (3) Structural design

[0010] With the increasing demand for high-efficiency coatings in cutting technology, simple single coatings are no longer sufficient to meet cutting requirements. Therefore, multifunctional coating structures such as gradient coatings and soft / hard combination coatings are becoming increasingly widely used. In cutting applications, many studies have been conducted to improve the performance of hard coatings by combining different coating materials. For example, Li et al. deposited TiAlN-ZrN (A1), TiAlN-ZrN / TiAlNZrN (A2), ZrN-TiAlN-ZrN (A3), and ZrN-TiAlN-ZrN / TiAlN-ZrN (A4) coatings on cemented carbide and demonstrated that nano-multilayered ZrN / TiAlN as an intermediate layer can improve the hardness and wear resistance of the overall coating. The multilayered structures A2 and A4 exhibited high hardness values of 24.68±3.27GPa and 25.34±3.42GPa, respectively, and good wear resistance. However, current coating structure designs mainly combine TiAlN coatings with other metal nitride coatings, which does not address the high friction coefficient of TiAlN coatings.

[0011] (4) Surface laser modification

[0012] Laser post-processing technology of coating surface is a key means to optimize coating performance. By properly regulating the stress distribution state and surface morphology characteristics of the coating, the interface bonding strength and service life of the coated tool can be significantly improved. For example, Guan et al. irradiated TiAlN coating by nanolaser. The microstructure, mechanical and tribological properties of the original and irradiated TiAlN coatings were studied. The results showed that the surface roughness of the TiAlN coating first increased after 5 pulses of laser irradiation, and then gradually decreased with the further increase of the number of pulses. Compared with the original coating, the coating irradiated with 15 pulses showed higher hardness (reaching 33.4GPa) and bonding strength (112N), and excellent wear resistance (wear rate of 3.3×10 -6 mm 3 / Nm) and a low friction coefficient (0.37). This study shows that the mechanical and tribological properties of TiAlN coatings can be improved by grain refinement, transition zone formation and residual stress adjustment after surface treatment. However, in traditional laser processing, laser ablation is mostly completed in air and inert gas, which causes oxidation and melt sputtering of the processed surface under the action of the high-energy laser beam, resulting in defects such as heat-affected zones, cracks, bulges, burnt spots, fragments, and recast layers, which cause serious damage to the coating surface. Figure 1Liquid phase laser processing has the advantage of alleviating the thermal effects of traditional laser ablation processes, but the light scattering and shielding effects of cavitation bubbles, suspended debris, and turbulent liquid flow induced by the general base liquid assisted laser generally reduce the transmission stability of the laser beam, resulting in low energy efficiency and poor surface quality. Even with ultrashort pulse lasers, optical microablation will encounter problems such as recasting layer, redeposition of ablation debris, phase change, and induced cracks (such as Figure 2 This limits its application prospects. Summary of the Invention

[0013] Although existing technologies have made progress in improving the performance of TiAlN-based coatings and constructing multilayer coatings, they still face the following key problems and technical bottlenecks: (1) The physical property differences between the functional layers in traditional multilayer coating designs lead to serious interface stress concentration and performance conflicts; (2) The interface stability of the coating system is insufficient under high temperature and high load conditions; (3) Traditional laser processing causes thermal damage, and currently there is insufficient research on liquid-assisted laser processing coating technology to alleviate thermal damage.

[0014] To address these issues, the present invention achieves technological breakthroughs through two innovative dimensions: (1) Innovatively introducing nanofluid-assisted laser texturing technology, utilizing the high thermal conductivity and boundary lubrication effect of nanofluids to reduce laser processing thermal damage and improve the mechanical properties and bonding strength of TiAlN-based coatings. (2) By designing a three-layer composite coating structure of "support layer-interface layer-functional top layer" and constructing a synergistic strengthening mechanism of "TiAlN surface microtexture-Cr transition-DLC surface layer", the coating system has both excellent mechanical properties and interface bonding strength.

[0015] In order to solve the above-mentioned technical problems, this application provides the following technical solutions:

[0016] The present invention provides a method for preparing a nanofluid-assisted laser-textured DLC / Cr / TiAlN composite coating, comprising the following steps:

[0017] S11: After pre-treating the surface of the coating substrate, a TiAlN coating is prepared on the surface of the coating substrate by magnetron sputtering to obtain a composite coating A; a mixed gas of argon and nitrogen is used during the magnetron sputtering;

[0018] S12: placing the composite coating A in a nanofluid for laser texturing treatment; the laser texturing treatment method comprises focusing an ultraviolet nanosecond laser through the nanofluid onto the surface of the TiAlN coating through an objective lens, and adjusting the focus position multiple times; during the laser texturing treatment, the defocus amount of the laser processor is -80 to -100 μm;

[0019] S13: By pulsed magnetron sputtering, a Cr interface layer and a DLC (diamond-like carbon) functional top layer are sequentially deposited on the surface of the composite coating A that has been laser textured in step S12 to obtain the nanofluid-assisted laser textured DLC / Cr / TiAlN composite coating.

[0020] Preferably, the material of the coating substrate is selected from high-speed steel, cemented carbide or ceramic.

[0021] Preferably, in step S11, the pretreatment method is ultrasonic cleaning in water, ethanol and acetone respectively after grinding and polishing.

[0022] Preferably, in step S11, the pressure ratio of argon gas to nitrogen gas during magnetron sputtering is 3:7.

[0023] Preferably, in step S12, the nanofluid is a fluid medium containing aluminum oxide nanoparticles, ferrosoferric oxide nanoparticles or silicon dioxide nanoparticles; and the fluid medium is composed of water and a surfactant.

[0024] Furthermore, the surfactant is selected from a zwitterionic surfactant or a cationic surfactant.

[0025] Specifically, the zwitterionic surfactant is selected from sodium lauryl iminodipropionate (SLI), CAS No. 14960-06-6, purchased from Hubei Xinkang Pharmaceutical Chemical Co., Ltd.; the cationic surfactant is selected from cetyltrimethylammonium bromide (CTAB), CAS No. 57-09-0, purchased from Jinan Juyang Chemical Technology Co., Ltd.

[0026] Preferably, the distance between the TiAlN coating in the composite coating A and the nanofluid liquid surface is maintained at 1-2 mm.

[0027] Furthermore, the distance between the TiAlN coating and the nanofluid liquid surface is maintained by controlling the nanofluid to flow in opposite directions via two peristaltic pumps.

[0028] Furthermore, the flow parameter of the peristaltic pump is 1-5 mL / min.

[0029] Specifically, in the nanofluid-assisted laser processing, the liquid layer thickness is controlled at 1 to 2 mm, and a peristaltic pump is used to control the movement of the nanofluid, with the operation direction being opposite, to control the liquid layer thickness to remain at a fixed parameter, thereby realizing the recycling of the nanofluid.

[0030] Preferably, during the laser texturing treatment, the setting parameters of the ultraviolet nanosecond laser are: laser pulse power of 5-10 W, frequency of 100-400 kHz, pulse width of 13-15 ns, and scanning speed of 1000-2000 mm / s.

[0031] Specifically, the focal length of the field lens is 254 mm, the scanning range is 175 mm × 175 mm, the maximum beam diameter is 14 mm, the working distance is 259 mm, and the maximum focus radius is 30 μm.

[0032] The present invention adopts TiAlN, Cr, and DLC coatings to form a hard-tough-hard three-layer composite structure, and uses nanofluid-assisted laser processing technology to perform surface texturing on the TiAlN coating to improve the hardness and film-base bonding of the TiAlN coating, and optimize the interface bonding strength of the DLC / Cr / TiAlN composite coating. A method for preparing a nanofluid-assisted laser texturing DLC / Cr / TiAlN composite coating is proposed. The flow chart of the method is as follows: Figure 3 shown.

[0033] Specifically, (1) the present invention adopts a method of co-growth of a TiAl sputtering target under the reaction gas N2 to prepare a high-hardness TiAlN coating on the surface of the tool substrate, and uses it as a supporting layer; (2) nanofluid-assisted laser processing technology is used to texturize the TiAlN coating to produce a periodic microtexture; (3) on the surface of the textured TiAlN coating, a Cr / DLC coating is prepared by co-deposition of a Cr target and a WC target, wherein the Cr coating with high toughness, crack propagation resistance and low coating internal stress serves as the interface layer, and the self-lubricating DLC coating serves as the functional top layer. The tool coating as a whole presents a "hard-tough-hard" three-layer composite structure, achieving synergistic optimization of mechanical properties and long-term self-lubrication.

[0034] The present invention also provides a nanofluid-assisted laser-textured DLC / Cr / TiAlN composite coating prepared by the above preparation method.

[0035] The present invention also provides application of the nanofluid-assisted laser-textured DLC / Cr / TiAlN composite coating in dry cutting.

[0036] The technical solution of the present invention has the following advantages over the prior art:

[0037] 1. The DLC / Cr / TiAlN composite coating of the present invention presents a three-layer composite structure of "hard-tough-hard" as a whole. While having mechanical properties such as high thermal stability, high hardness, and high toughness, it also has self-lubricating functionality, which can achieve the coordinated optimization of multiple indicators of mechanical and functional performance of the coating;

[0038] 2. Nanofluid-assisted laser technology enables non-contact processing, generating a flexible vertical impact force on the surface of micron-thick coatings to prevent the coating from being ablated. In addition, the horizontal impact generated in the dynamic solution can accurately remove surface defects and improve the surface quality of the TiAlN coating.

[0039] 3. The periodic microtexture introduced into the DLC / Cr / TiAlN composite coating can effectively reduce the internal stress of the coating, thereby enhancing the interlayer bonding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Surface morphology of laser-textured TiAlN coating in air medium.

[0041] Figure 2 Surface morphology of laser-textured TiAlN coating in deionized water medium.

[0042] Figure 3 Flow chart of the method of the present invention.

[0043] Figure 4 This is the surface morphology of the laser-textured TiAlN coating in nanofluid medium.

[0044] Figure 5 Interface morphology and EDS element distribution map of nanofluid-assisted laser texturing DLC / Cr / TiAlN composite coating. DETAILED DESCRIPTION

[0045] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0046] Example 1:

[0047] A nanofluid-assisted laser-textured DLC / Cr / TiAlN composite coating uses WC / Co cemented carbide as the tool substrate. A three-layer functionally gradient coating is formed on a micrometer scale through gradient growth, layer growth, and co-growth of sputtering target particles. Periodic microtexture is introduced on the TiAlN coating surface to regulate the interlayer bonding strength, resulting in a "hard-tough-hard" three-layer composite structure. The specific preparation process steps are as follows:

[0048] 1. Matrix grinding and polishing, ultrasonic cleaning: The surface of the tool matrix is prepared on an automatic metallographic grinding machine for metallographic specimens, then ground with 1000# sandpaper using anhydrous ethanol, and then mirror polished using a natural fiber polishing cloth with W2.5 diamond polishing agent. Finally, ultrasonic cleaning is performed in water, ethanol and acetone for 30 minutes respectively to clean the surface;

[0049] 2. Preparation of TiAlN coating (support layer): The pressure of the working chamber was adjusted to 5×10 -4 Torr, and then start the heating system to stabilize the sample temperature at 360 ° C, using Ar +The sample was etched clean by ions and maintained at this condition for 20 minutes. After the pretreatment stage, the system temperature was adjusted to the optimized etching temperature range of 90°C and precision etching was continued for 150 minutes to completely remove the surface oxide layer and organic contaminants.

[0050] During the formal deposition phase, a 6×10 -5 Torr pressure environment, and use the TiAl alloy target with an atomic ratio of 50:50 to prepare the coating. The sample temperature is set to 400℃, and a pulsed negative bias of -120V is applied with a duty cycle of 60%. After the vacuum and temperature meet the requirements, high-purity Ar gas is introduced to pre-sputter clean the TiAl alloy target for 5 minutes, and then the Ar gas pressure is adjusted to 0.5Pa, and the Ti transition layer is deposited for 5 minutes. Then high-purity N2 is introduced and the P is adjusted. N2 / (P Ar +P N2 ) = 30%, maintaining the total gas pressure at 0.5 Pa, and preparing the TiAlN coating;

[0051] 3. Fabrication of periodic microtexture on the TiAlN support layer: A nanofluid containing 1% Al2O3 nanoparticles (average particle size approximately 30 nm) dispersed in deionized water was used as the liquid medium. A cleaned TiAlN-coated tool was placed in the nanofluid. Two peristaltic pumps were set at a flow rate of 1 mL / min, operating in different directions, to maintain a liquid layer thickness of 1 mm. The laser was operated at approximately 25°C and a defocus of -80 μm during the experiment. The ultraviolet nanosecond laser is focused through the liquid onto the surface of the TiAlN coating through the objective lens, and the scanning process path and laser processing parameters of the laser processor are set: the laser pulse power is 8W, the frequency is 250KHz, the pulse width is 13ns, the scanning speed is 1000mm / s, the focal length of the field lens is 254mm, the scanning range is 175mm×175mm, the maximum beam diameter is 14mm, the working distance is 259mm, and the maximum focus radius is 35μm; the lifting handle is manually adjusted to change the position of the scanning galvanometer module, change the focusing position of the laser on the material surface, and complete the laser texturing treatment.

[0052] 4. Preparation of Cr / DLC coating (interface layer / functional top layer): The pulsed magnetron sputtering system uses a turbomolecular pump to extract the air in the system to reach 2.0×10 -3The vacuum condition of the base pressure of Pa is maintained, and the turbomolecular pump is supported by a rough vacuum pump. For vacuum arc discharge, the main arc starts through a point-to-point path on the surface of the ceramic insulator deposited between the cathode and the anode, allowing plasma to be generated at the cathode point. Before depositing the DLC coating, the TiAlN coating surface is bombarded with Cr ions for 5 minutes at a high voltage DC bias of -1000V to remove the oxide layer on its surface and form a Cr interface layer between the TiAlN coating surface and the DLC coating. Then, the deposition temperature is 200℃ and the cathode power density is 13w / cm 2 The DLC coating was fabricated using two WC targets under the conditions of -1000 V bottom bias pulse current and 8.5 h cycle time.

[0053] Example 2:

[0054] A nanofluid-assisted laser-textured DLC / Cr / TiAlN composite coating. The tool substrate material is high-speed steel. A three-layer functional gradient coating at the micron scale is formed on its surface through layer growth and co-growth of sputtering target particles. Periodic microtexture is introduced on the surface of the TiAlN coating to regulate the interlayer bonding strength, so that the tool coating as a whole presents a "hard-tough-hard" three-layer composite structure.

[0055] The specific preparation process steps are as follows:

[0056] 1. Matrix grinding and polishing, ultrasonic cleaning: The tool matrix surface was prepared on an automatic metallographic grinding machine for metallographic specimens, then ground with 1000# sandpaper using anhydrous ethanol, and then mirror polished using a natural fiber polishing cloth with W2.5 diamond polishing agent. Finally, ultrasonic cleaning was performed in water, ethanol, and acetone for 20 minutes respectively to clean the surface;

[0057] 2. Preparation of TiAlN coating (support layer): The TiAlN coating was prepared using vacuum cathode arc ion plating technology. After the substrate sample was dried, it was placed in a vacuum chamber and arranged on a rotating sample holder with multiple degrees of freedom. After the substrate was placed, the vacuum chamber was evacuated and the pressure reached 1.0×10 -2 Pa and then gradually heated until the temperature reached 200 °C, and kept warm until the vacuum degree was less than 7 × 10 -3 Pa below; introduce Ar gas, use high energy Ar + The particles bombarded the substrate material for pre-sputtering cleaning for 15 minutes; a pair of independent Ti targets and TiAl targets were used with N2 gas to deposit the TiAlN coating. During the coating process, the substrate negative bias voltage was controlled at -40 to -150 V, and the deposition time was 60 minutes.

[0058] 3. Fabrication of periodic microtexture on the TiAlN support layer surface: A 0.5% volume concentration of Fe₃O₄ magnetic nanofluid (average particle size approximately 10 nm) with SLI as a surfactant was used as the liquid medium. A cleaned TiAlN-coated tool was placed in the nanofluid. Two peristaltic pumps were set at a flow rate of 1.5 mL / min, operating in different directions, to maintain a liquid layer thickness of 1.5 mm. The laser was operated at approximately 25°C and a defocus of -100 μm during the experiment. The ultraviolet nanosecond laser is focused through the liquid onto the surface of the TiAlN coating through the objective lens, and the scanning process path and laser processing parameters of the laser processor are set: the laser pulse power is 6W, the frequency is 250KHz, the pulse width is 13ns, the scanning speed is 2000mm / s, the focal length of the field lens is 260mm, the scanning range is 175mm×175mm, the maximum beam diameter is 14mm, the working distance is 265mm, and the maximum focus radius is 25μm; the lifting handle is manually adjusted to change the position of the scanning galvanometer module, change the focusing position of the laser on the material surface, and complete the laser texturing treatment.

[0059] 4. Preparation of Cr / DLC coating (interface layer / functional top layer): The surface textured TiAlN coating was ultrasonically cleaned and placed on a workbench after drying. The pressure in the working chamber was adjusted to 5×10 -4 Torr, and then start the heating system to stabilize the sample temperature at 360 ° C, using Ar + The sample was etched clean by ions and maintained at this condition for 20 minutes. After the pretreatment stage, the system temperature was adjusted to the optimized etching temperature range of 90°C and precision etching was continued for 150 minutes to completely remove the surface oxide layer and organic pollutants. In the formal deposition stage, a 6×10 -5 Torr pressure environment, and deposit Cr and DLC coatings in sequence at a deposition temperature of 180°C according to preset process parameters.

[0060] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a nanofluid-assisted laser-textured DLC / Cr / TiAlN composite coating, characterized in that: The steps include: S11: After pre-treating the surface of the coating substrate, a TiAlN coating is prepared on the surface of the coating substrate by magnetron sputtering to obtain a composite coating A; a mixed gas of argon and nitrogen is used during the magnetron sputtering; S12: placing the composite coating A in a nanofluid for laser texturing treatment; the laser texturing treatment method comprises focusing an ultraviolet nanosecond laser through the nanofluid onto the surface of the TiAlN coating through an objective lens, and adjusting the focus position multiple times; during the laser texturing treatment, the defocus amount of the laser processor is -80 to -100 μm; S13: By pulsed magnetron sputtering, a Cr interface layer and a DLC functional top layer are sequentially deposited on the surface of the composite coating A that has been laser textured in step S12 to obtain the nanofluid-assisted laser textured DLC / Cr / TiAlN composite coating.

2. The preparation method according to claim 1, wherein The material of the coating substrate is selected from high-speed steel, cemented carbide or ceramic.

3. The preparation method according to claim 1, wherein In the step S11, the pretreatment method is to perform ultrasonic cleaning in water, ethanol and acetone respectively after grinding and polishing.

4. The preparation method according to claim 1, wherein In step S12, the nanofluid is a fluid medium containing aluminum oxide nanoparticles, ferrosoferric oxide nanoparticles or silicon dioxide nanoparticles; and the fluid medium is composed of water and a surfactant.

5. The preparation method according to claim 1, wherein The distance between the TiAlN coating in the composite coating A and the nanofluid liquid surface is maintained at 1-2 mm.

6. The preparation method according to claim 5, wherein The distance between the TiAlN coating and the nanofluid liquid surface is maintained by controlling the nanofluid to flow in opposite directions via two peristaltic pumps.

7. The preparation method according to claim 6, wherein The flow rate parameter of the peristaltic pump is 1-5 mL / min.

8. The preparation method according to claim 1, wherein During the laser texturing treatment, the setting parameters of the ultraviolet nanosecond laser are: laser pulse power of 5-10W, frequency of 100-400kHz, pulse width of 13-15ns, and scanning speed of 1000-2000mm / s.

9. A nanofluid-assisted laser-textured DLC / Cr / TiAlN composite coating prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the nanofluid-assisted laser-textured DLC / Cr / TiAlN composite coating according to claim 9 in dry cutting.

Images