A composite self-lubricating coating for a cutting tool and a method of making the same

Abstract

The present application belongs to the technical field of coated tools, and particularly relates to a composite self-lubricating coating for a tool and a preparation method thereof. The composite self-lubricating coating for a tool comprises a WS2 interface adaptation layer, a WS2 / MoS2 buffer transition layer, a TiAlMoN main bearing wear-resistant layer, a TiAlMoN / Ni lubricating phase composite layer, and a W-C-N surface interface functional gradient layer. The present application solves the inherent contradiction between high strength and low friction, high bonding force and stress release through the design of a five-layer structure with different functions and performance gradient transition. The coating of the present application has ultrahigh hardness (≥35 GPa), extremely low friction coefficient (≤0.15), and excellent bonding strength (critical load Lc2≥80 N), and has high comprehensive performance. The WS2 / MoS2 buffer transition layer, the TiAlMoN / Ni lubricating phase composite layer, and the outermost W-C-N surface interface functional gradient layer of the present application can ensure effective lubrication and stable performance under the high-temperature environment generated by cutting.

Description

Technical Field

[0001] This invention belongs to the field of coated cutting tool technology, specifically a composite self-lubricating coating for cutting tools and its preparation method. Background Technology

[0002] Cutting tools are widely used in the machining field due to their high hardness, good wear resistance, and red hardness. However, under harsh conditions such as high-speed cutting and dry cutting, intense friction and high temperature are generated between the tool and the workpiece material, leading to problems such as tool wear, adhesion (built edge), diffusion, and oxidation, which accelerate tool failure and affect machining accuracy and surface quality.

[0003] To improve tool performance, physical vapor deposition (PVD) coating technology is widely used, such as traditional single-layer coatings like TiN, TiAlN, and CrN. These coatings enhance wear resistance by increasing surface hardness, but they have poor self-lubricating properties and typically have a high coefficient of friction (>0.4). Their lubrication effect is limited during high-temperature and continuous cutting, making it difficult to meet the comprehensive requirements of modern high-efficiency machining for low friction and high wear resistance.

[0004] Subsequent developments have included soft-hard composite coatings or multilayer structures, such as lubricating coatings doped with MoS2 or WS2. These soft phases can provide a lower coefficient of friction, but their load-bearing capacity and bonding strength with the substrate are often insufficient, making them prone to early spalling failure under high loads. Furthermore, due to differences in physical and chemical properties between layers, there may be issues such as high internal stress and poor bonding strength.

[0005] Therefore, there is an urgent need in this field for a new coating system that can organically combine high hardness, high bonding strength and excellent self-lubricating properties, and alleviate interlayer stress through reasonable structural design, thereby adapting to more stringent processing conditions. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the first aspect of the present invention provides a composite self-lubricating coating for cutting tools, which includes, from the substrate surface outwards: a WS2 interface adaptation layer, a WS2 / MoS2 buffer transition layer, a TiAlMoN main load-bearing and wear-resistant layer, a TiAlMoN / Ni lubricating phase composite layer, and a WCN surface and interface functional gradient layer.

[0007] In the WS2 interface adapter layer, the atomic ratio of W to S is 1:(1.9~2.1), the WS2 interface adapter layer has a 2H hexagonal crystal form, the grain size of the WS2 interface adapter layer is 10~30nm, the nanoindentation hardness is 4~6GPa, and the friction coefficient is 0.3~0.35.

[0008] The WS2 / MoS2 buffer transition layer is a (W, Mo)S2 solid solution with an atomic ratio of (W+Mo) to S of 1:(1.9~2.1). The atomic ratio of W to Mo changes linearly from 4:1 to 1:4 from the inner layer to the outer layer. The grain size of the WS2 / MoS2 buffer transition layer is 20~50nm, the nanoindentation hardness increases from 6~8GPa to 8~12GPa from the inner layer to the outer layer, and the friction coefficient is 0.2~0.3.

[0009] The TiAlMoN main load-bearing wear-resistant layer is a face-centered cubic (Ti, Al, Mo)N solid solution with an atomic ratio of (Ti+Al+Mo) to N of 1:(0.95~1.05), an atomic ratio of Al to Ti of (0.8~1.2):1, and an atomic percentage of Mo of 2%~5%. The grain size of the TiAlMoN main load-bearing wear-resistant layer is 30~60nm, the nanoindentation hardness is ≥38GPa, and the coefficient of friction is 0.5~0.65.

[0010] The TiAlMoN / Ni lubricating phase composite layer is composed of a face-centered cubic (Ti, Al, Mo)N phase and a metallic Ni phase. The atomic percentage of Ni is 3%~8%, the grain size is 20~40nm, the nanoindentation hardness is 28~32GPa, and the friction coefficient is 0.15~0.20.

[0011] In the WCN interface functional gradient layer, the atomic ratio of C to N increases linearly from 0.2:1 to 5:1 from the inner layer to the outer layer. The phase composition of the WCN interface functional gradient layer includes WN, W2C, WC and amorphous carbon, with a grain size of 10~50nm, a nanoindentation hardness of 18~25GPa, and a friction coefficient of 0.10~0.12.

[0012] The thickness of the WS2 interface adapter layer is 0.1~0.3μm; the thickness of the WS2 / MoS2 buffer transition layer is 0.5~1.0μm; the thickness of the TiAlMoN main load-bearing and wear-resistant layer is 1.0~2.0μm; the thickness of the TiAlMoN / Ni lubricating phase composite layer is 1.0~2.0μm; the thickness of the WCN surface functional gradient layer is 0.5~1.0μm; and the total thickness of the composite self-lubricating coating is 3.1~6.3μm.

[0013] The composite self-lubricating coating has a nano-indentation hardness ≥35GPa, a friction coefficient ≤0.15, and a critical load Lc2 for bonding strength ≥80N.

[0014] A second aspect of this invention provides a method for preparing a composite self-lubricating coating for cutting tools according to the first aspect of this invention. The method involves sequentially depositing the WS2 interface adaptation layer, the WS2 / MoS2 buffer transition layer, the TiAlMoN main load-bearing and wear-resistant layer, the TiAlMoN / Ni lubricating phase composite layer, and the WCN surface functional gradient layer on a substrate using high-power pulsed magnetron sputtering technology. The bias voltage for depositing the WS2 interface adaptation layer is -80 to -100V, the WS2 target power is 6kW, and the gas pressure is 0.3 kWh. The deposition time was 10-15 min, with an Ar flow rate of 50 sccm and a temperature of 650-700℃. The bias voltage for depositing the WS2 / MoS2 buffer transition layer was -80 to -100V. The WS2 target power was linearly varied from 6 kW to 2 kW over time, and the MoS2 target power was linearly varied from 2 kW to 6 kW over time. The gas pressure was 0.3-0.5 Pa, the Ar flow rate was 50 sccm, the temperature was 650-700℃, and the time was 30-45 min. The deposition time for the TiA2 / MoS2 buffer transition layer was 30-45 min. The bias voltage for depositing the TiAlMoN main bearing wear-resistant layer is -60 to -80 V, the TiAlMoN target power is 8 kW, the gas pressure is 0.4 to 0.6 Pa, the Ar flow rate is 40 sccm, the N2 flow rate is 60 sccm, the temperature is 650 to 700 °C, and the time is 90 to 120 min. The bias voltage for depositing the TiAlMoN / Ni lubricating phase composite layer is -60 to -80 V, the TiAlMoN target power is 8 kW, the Ni target power is 5 kW, the gas pressure is 0.4 to 0.6 Pa, and the Ar flow rate is 40 sccm. The N2 flow rate was 60 sccm, the temperature was 650~700℃, and the time was 60~90 min; the bias voltage for depositing the functionally graded layer at the WCN interface was -40~-60V, the W target power was 5kW, the gas pressure was 0.5~0.7Pa, the Ar flow rate was 30 sccm, the N2 flow rate changed linearly from 40 sccm to 8 sccm over time, the C2H2 flow rate changed linearly from 8 sccm to 40 sccm over time, the temperature was 650~700℃, and the time was 30~45 min.

[0015] A third aspect of the present invention also provides a cutting tool with a composite self-lubricating coating, comprising a substrate and a coating, wherein the coating is a composite self-lubricating coating for cutting tools provided in the first aspect of the present invention.

[0016] Beneficial effects:

[0017] This invention perfectly resolves the inherent contradictions between high strength and low friction, and high bonding strength and stress release through a five-layer structure design with different functions and gradient performance transitions. The coating of this invention simultaneously possesses ultra-high hardness (≥35GPa), extremely low coefficient of friction (≤0.15), and excellent bonding strength (critical load Lc2≥80N), exhibiting high overall performance. The WS2 / MoS2 buffer transition layer, TiAlMoN / Ni lubricating phase composite layer, and the outermost WCN surface interface functional gradient layer in this invention can all ensure effective lubrication and stable performance under the high-temperature environment generated by cutting. This invention employs high-power pulsed magnetron sputtering technology, and through precise control of process parameters, it can achieve precise control of the chemical composition, microstructure, and thickness of each layer, resulting in good process repeatability and suitability for industrial production. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the cross-sectional structure of the cutting tool with a composite self-lubricating coating according to the present invention.

[0020] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This invention provides a composite self-lubricating coating for cutting tools, which includes, from the substrate surface outwards, the following layers in sequence: WS2 interface adaptation layer, WS2 / MoS2 buffer transition layer, TiAlMoN main load-bearing and wear-resistant layer, TiAlMoN / Ni lubricating phase composite layer, and WCN surface and interface functional gradient layer.

[0023] Please see Figure 1 , Figure 1This is a schematic diagram of the cross-sectional structure of the cutting tool with a composite self-lubricating coating of the present invention, including: a substrate 100, a WS2 interface adaptation layer 200, a WS2 / MoS2 buffer transition layer 300, a TiAlMoN main load-bearing and wear-resistant layer 400, a TiAlMoN / Ni lubricating phase composite layer 500, and a WCN surface and interface functional gradient layer 600.

[0024] Among them, the WS2 interface adaptation layer 200: This layer is directly deposited on the substrate 100. Its main function is to improve the physical and chemical compatibility between the subsequent coating and the substrate 100, relieve thermal stress and internal stress, and improve the overall bonding strength of the coating.

[0025] WS2 / MoS2 buffer transition layer 300: This layer serves as a transition region in chemical composition, with a gradient change in the ratio of W to Mo atoms. It effectively buffers the stress caused by the mismatch in lattice constant and thermal expansion coefficient between the inner WS layer and the outer nitride layer, thus avoiding abrupt changes in performance at the interface.

[0026] TiAlMoN Main Load-Bearing Wear-Resistant Layer 400: This layer is the core load-bearing layer of the coating, providing extremely high hardness and wear resistance, and bearing the main mechanical and thermal loads during the cutting process;

[0027] TiAlMoN / Ni lubricating phase composite layer 500: This layer has a composite structure in which a soft metallic Ni phase is composited in a hard TiAlMoN matrix. Ni is easy to slip or drag during friction to form a lubricating film, thereby significantly reducing the coefficient of friction and maintaining stable lubrication performance, especially at high temperatures.

[0028] WCN surface functional gradient layer 600: As the outermost layer, its C / N atomic ratio increases from the inside to the outside, forming a structure that transitions from a nitrogen-rich hard phase to a carbon-rich (especially amorphous carbon) lubricating phase. This layer ensures both a low coefficient of friction on the surface and sufficient strength to support the load, preventing the soft lubricating layer from being worn through prematurely.

[0029] Example 1

[0030] WNMG 080408E-MC3 type cemented carbide is used as the matrix;

[0031] S0. Substrate preparation: The substrate to be coated is pretreated by cleaning, degreasing, and rust removal to ensure that the substrate surface is clean and free of impurities.

[0032] S1 and WS2 interface adapter layer deposition: The pretreated substrate was placed in a PVD coating furnace, and the WS2 interface adapter layer was deposited on the substrate surface by ion bombardment. The process parameters were: substrate bias voltage of -90V, WS2 target power of 6kW, gas pressure of 0.4Pa, Ar flow rate of 50sccm, deposition temperature of 680°C, deposition time of 12min, and deposition thickness of 0.2μm.

[0033] S2 and WS2 / MoS2 buffer transition layer deposition: On top of the WS2 interface adapter layer, the WS2 / MoS2 buffer transition layer is deposited. The process parameters are as follows: substrate bias voltage is -90V, WS2 target power is linearly varied from 6kW to 2kW over time, MoS2 target power is linearly varied from 2kW to 6kW over time, gas pressure is 0.4Pa, Ar flow rate is 50sccm, deposition temperature is 680°C, deposition time is 40min, and deposition thickness is 0.8μm.

[0034] S3, TiAlMoN Main Load-Bearing Wear-Resistant Layer Deposition: On top of the WS2 / MoS2 buffer transition layer, the TiAlMoN main load-bearing wear-resistant layer is deposited. The process parameters are as follows: substrate bias voltage is -70V, TiAlMo target (atomic ratio Ti:Al:Mo=1:1:0.1) power is 8kW, gas pressure is 0.5Pa, Ar flow rate is 40sccm, N2 flow rate is 60sccm, deposition temperature is 680°C, deposition time is 100min, and deposition thickness is 1.5μm.

[0035] S4. Deposition of TiAlMoN / Ni lubricating phase composite layer: On top of the TiAlMoN main load-bearing and wear-resistant layer, a TiAlMoN / Ni lubricating phase composite layer is deposited. The process parameters are as follows: substrate bias voltage is -70V, TiAlMo target power (atomic ratio Ti:Al:Mo=1:1:0.1) is 8kW, Ni target power is 5kW, gas pressure is 0.5Pa, Ar flow rate is 40sccm, N2 flow rate is 60sccm, deposition temperature is 680°C, deposition time is 75min, and deposition thickness is 1.5μm.

[0036] S5. Deposition of WCN Surface and Interface Functional Gradient Layer: A WCN surface and interface functional gradient layer was deposited on top of the TiAlMoN / Ni lubricating phase composite layer. The process parameters were: substrate bias voltage -50V, target power 5kW, gas pressure 0.6Pa, Ar flow rate 30sccm, N2 flow rate linearly varying from 40sccm to 8sccm over time, C2H2 flow rate linearly varying from 8sccm to 40sccm over time, deposition temperature 680°C, deposition time 40min, and deposition thickness 0.8μm.

[0037] S6. Post-treatment: After deposition, a multi-layer coating with a total thickness of 4.8μm is obtained. Post-treatments such as sandblasting and polishing are then performed to eliminate internal stress in the coating, thereby improving the adhesion and stability of the coating.

[0038] Example 2

[0039] The difference from Example 1 is:

[0040] RPHT 1204M8E-MM3 cemented carbide is used as the matrix;

[0041] The process parameters for depositing the WS2 interface adapter layer are: substrate bias voltage of -85V, deposition temperature of 660℃, deposition time of 14min, and deposition thickness of approximately 0.25μm.

[0042] The process parameters for depositing the WS2 / MoS2 chemical buffer transition layer are as follows: substrate bias voltage of -95V, deposition temperature of 660℃, deposition time of 35min, and deposition thickness of approximately 0.7μm.

[0043] The process parameters for depositing the TiAlMoN main load-bearing wear-resistant layer are: substrate bias voltage of -65V, deposition temperature of 660℃, deposition time of 110min, and deposition thickness of approximately 1.7μm.

[0044] The process parameters for depositing the TiAlMoN / Ni lubricating phase composite layer are as follows: substrate bias voltage of -75V, deposition temperature of 660℃, deposition time of 80min, and deposition thickness of approximately 1.6μm.

[0045] The process parameters for depositing the WCN surface functional gradient layer are as follows: substrate bias voltage of -55V, deposition temperature of 660℃, deposition time of 38min, and deposition thickness of approximately 0.75μm.

[0046] After deposition, a multi-layer composite coated tool with a total thickness of approximately 5.0 μm is obtained.

[0047] Example 3

[0048] The difference from Example 1 is:

[0049] APMT 1604PDER type cemented carbide is used as the matrix;

[0050] The process parameters for depositing the WS2 interface adapter layer are as follows: substrate bias voltage of -95V, deposition temperature of 670℃, deposition time of 10min, and deposition thickness of approximately 0.15μm.

[0051] The process parameters for depositing the WS2 / MoS2 chemical buffer transition layer are as follows: substrate bias voltage of -85V, deposition temperature of 670℃, deposition time of 38min, and deposition thickness of approximately 0.75μm.

[0052] The process parameters for depositing the TiAlMoN main load-bearing wear-resistant layer are as follows: substrate bias voltage of -75V, deposition temperature of 670℃, deposition time of 105min, and deposition thickness of approximately 1.6μm.

[0053] The process parameters for depositing the TiAlMoN / Ni lubricating phase composite layer are as follows: substrate bias voltage of -65V, deposition temperature of 660℃, deposition time of 70min, and deposition thickness of approximately 1.4μm.

[0054] The process parameters for depositing the WCN surface functional gradient layer are as follows: substrate bias voltage of -45V, deposition temperature of 670℃, deposition time of 43min, and deposition thickness of approximately 0.9μm.

[0055] After deposition, a multi-layer composite coated tool with a total thickness of approximately 4.8 μm was obtained.

[0056] Comparative Example 1

[0057] Unlike Example 1, only one TiAlN coating layer with a thickness of 4.8 μm was deposited. Process parameters: substrate bias voltage of -70V, TiAl target power (atomic ratio Ti:Al=1:1) of 8kW, gas pressure of 0.5Pa, Ar flow rate of 40sccm, N2 flow rate of 60sccm, deposition temperature of 680°C, and deposition time of 300min.

[0058] Comparative Example 2

[0059] Unlike Example 1, a TiAlN coating with a thickness of 3 μm was deposited for 185 min. Then, a 1.8 μm WS2 lubricant layer was deposited on top of the TiAlN coating. The process parameters were: substrate bias voltage of -60V, WS2 target power of 6kW, gas pressure of 0.4Pa, Ar flow rate of 50sccm, deposition temperature of 680℃, and deposition time of 30 min.

[0060] Comparative Example 3

[0061] Unlike Example 2, no WS2 / MoS2 chemical buffer transition layer was deposited; that is, after the WS2 interface adaptation layer was prepared, the TiAlMoN main load-bearing and wear-resistant layer was directly deposited.

[0062] Comparative Example 4

[0063] Unlike Example 2, no TiAlMoN / Ni lubricating phase composite layer was deposited; that is, after the TiAlMoN main load-bearing and wear-resistant layer was prepared, the WCN surface interface functional gradient layer was directly deposited.

[0064] Comparative Example 5

[0065] The difference from Example 3 is that in the WS2 / MoS2 buffer layer, the WS2 target power is constant at 4kW and the MoS2 target power is constant at 4kW, that is, the atomic ratio of W to Mo does not change from the inner layer to the outer layer.

[0066] Comparative Example 6

[0067] The difference from Example 3 is that the N2 flow rate is constant at 24 sccm and the C2H2 flow rate is constant at 24 sccm, meaning that the N and C atomic ratio does not change gradient from the inner layer to the outer layer.

[0068] The coating samples prepared in Examples 1, 2, 3 and Comparative Examples 1, 2, 3, 4, 5, 6 were subjected to performance tests, and the results are shown in Table 1.

[0069] Table 1

[0070]

[0071] The coating samples prepared in Example 1 and Comparative Examples 1 and 2 were subjected to cutting tests to process cast iron parts. The cutting speed was 350 m / min and the time was 60 min. The results are shown in Table 2.

[0072] Table 2

[0073]

[0074] The coating samples prepared in Example 2 and Comparative Examples 3 and 4 were subjected to cutting tests. Stainless steel was machined at a cutting speed of 150 m / min for 30 min. The results are shown in Table 3.

[0075] Table 3

[0076]

[0077] The coating samples prepared in Example 3 and Comparative Examples 5 and 6 were subjected to cutting tests to process titanium alloys at a cutting speed of 100 m / min for 30 min. The results are shown in Table 4.

[0078] Table 4

[0079]

[0080] The flank face refers to the tool surface adjacent to the cutting edge and opposite to the workpiece during the cutting process. In Tables 2, 3, and 4, the flank face wear refers to the vertical distance between the point of maximum flank face wear and the cutting edge.

[0081] This invention provides a multilayer composite self-lubricating coating for cutting tools and its preparation method. Through multilayer structure design and element doping technology, it achieves an optimized balance between coating hardness and lubrication performance, solving the problems of high friction coefficient and insufficient lubrication performance of existing tool coatings under high-temperature environments. The coating is prepared using high-power pulsed magnetron sputtering (HiPIMS) technology, and the layers have excellent interfacial adhesion and structural continuity, significantly improving the wear resistance, oxidation resistance, and service life of the cutting tool. Any damage to the overall structure will lead to a significant decrease in coating performance, which underscores the inventiveness and necessity of this invention.

[0082] In summary, this invention, through its innovative multi-layer composite self-lubricating coating structure, successfully achieves a synergistic improvement in three key performance indicators: high hardness, low coefficient of friction, and high adhesion, resulting in significant overall performance advantages.

[0083] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A composite self-lubricating coating for a cutting tool, characterized by From the substrate surface outwardly in turn includes: WS2 interface adaptation layer, WS2 / MoS2 buffer transition layer, TiAlMoN main bearing wear-resistant layer, TiAlMoN / Ni lubricating phase composite layer, W-C-N surface interface functional gradient layer; The WS2 / MoS2 buffer transition layer is a (W, Mo) S2 solid solution, the atomic ratio of (W+Mo) and S is 1:(1.9-2.1), and the atomic ratio of W to Mo linearly changes from 4:1 to 1:4 from the inner layer to the outer layer; In the W-C-N surface interface functional gradient layer, the atomic ratio of C to N linearly increases from 0.2:1 to 5:1 from the inner layer to the outer layer.

2. A composite self-lubricating coating for a cutting tool according to claim 1, characterized in that In the WS2 interface adaptation layer, the atomic ratio of W to S is 1:(1.9-2.1), the WS2 interface adaptation layer has a 2H hexagonal crystal structure, the grain size of the WS2 interface adaptation layer is 10-30 nm, the nanoindentation hardness is 4-6 GPa, and the friction coefficient is 0.3-0.

35.

3. A composite self-lubricating coating for a cutting tool according to claim 1, wherein The grain size of the WS2 / MoS2 buffer transition layer is 20-50 nm, the nanoindentation hardness linearly increases from 6-8 GPa to 8-12 GPa from the inner layer to the outer layer, and the friction coefficient is 0.2-0.

3.

4. A composite self-lubricating coating for a cutting tool according to claim 1, wherein The TiAlMoN main bearing wear-resistant layer is a (Ti, Al, Mo) N solid solution with a face-centered cubic structure, the atomic ratio of (Ti+Al+Mo) to N is 1:(0.95-1.05), the atomic ratio of Al to Ti is (0.8-1.2):1, and the atomic percentage of Mo is 2%-5%, the grain size of the TiAlMoN main bearing wear-resistant layer is 30-60 nm, the nanoindentation hardness is greater than or equal to 38 GPa, and the friction coefficient is 0.5-0.

65.

5. A composite self-lubricating coating for a cutting tool according to claim 1, wherein The TiAlMoN / Ni lubricating phase composite layer is composed of a (Ti, Al, Mo) N phase and a metal Ni phase with a face-centered cubic structure, the atomic percentage of Ni is 3%-8%, the grain size is 20-40 nm, the nanoindentation hardness is 28-32 GPa, and the friction coefficient is 0.15-0.

20.

6. A composite self-lubricating coating for a cutting tool according to claim 1, wherein The W-C-N surface interface functional gradient layer includes WN, W2C, WC and amorphous carbon, the grain size is 10-50 nm, the nanoindentation hardness is 18-25 GPa, and the friction coefficient is 0.10-0.

12.

7. A composite self-lubricating coating for a cutting tool according to claim 1, wherein The thickness of the WS2 interface adaptation layer is 0.1-0.3 μm, the thickness of the WS2 / MoS2 buffer transition layer is 0.5-1.0 μm, the thickness of the TiAlMoN main bearing wear-resistant layer is 1.0-2.0 μm, the thickness of the TiAlMoN / Ni lubricating phase composite layer is 1.0-2.0 μm, the thickness of the W-C-N surface interface functional gradient layer is 0.5-1.0 μm, and the total thickness of the composite self-lubricating coating is 3.1-6.3 μm.

8. A composite self-lubricating coating for a cutting tool according to claim 1, wherein The nanoindentation hardness of the composite self-lubricating coating is greater than or equal to 35 GPa, the friction coefficient is less than or equal to 0.15, and the critical load Lc2 of the bonding strength is greater than or equal to 80 N.

9. A method for producing a composite self-lubricating coating for cutting tools according to any one of claims 1 to 8, characterized in that, The WS2 interface adaptation layer, the WS2 / MoS2 buffer transition layer, the TiAlMoN main bearing wear-resistant layer, the TiAlMoN / Ni lubricating phase composite layer and the W-C-N surface interface functional gradient layer are sequentially deposited on the substrate by using a high-power pulsed magnetron sputtering technology. The bias voltage for depositing the WS2 interface adaptation layer is -80~ -100 V, the WS2 target power is 6 kW, the gas pressure is 0.3~0.5 Pa, the Ar flow rate is 50 sccm, the temperature is 650~700℃, and the time is 10~15 min. The bias voltage for depositing the WS2 / MoS2 buffer transition layer is -80~ -100 V, the WS2 target power is linearly changed from 6 kW to 2 kW over time, the MoS2 target power is linearly changed from 2 kW to 6 kW over time, the gas pressure is 0.3~0.5 Pa, the Ar flow rate is 50 sccm, the temperature is 650~700℃, and the time is 30~45 min. The bias voltage for depositing the TiAlMoN main bearing wear-resistant layer is -60~ -80 V, the TiAlMoN target power is 8 kW, the gas pressure is 0.4~0.6 Pa, the Ar flow rate is 40 sccm, the N2 flow rate is 60 sccm, the temperature is 650~700℃, and the time is 90~120 min. The bias voltage for depositing the TiAlMoN / Ni lubricating phase composite layer is -60~ -80 V, the TiAlMoN target power is 8 kW, the Ni target power is 5 kW, the gas pressure is 0.4~0.6 Pa, the Ar flow rate is 40 sccm, the N2 flow rate is 60 sccm, the temperature is 650~700℃, and the time is 60~90 min. The bias voltage for depositing the W-C-N surface interface functional gradient layer is -40~ -60 V, the W target power is 5 kW, the gas pressure is 0.5~0.7 Pa, the Ar flow rate is 30 sccm, the N2 flow rate is linearly changed from 40 sccm to 8 sccm over time, the C2H2 flow rate is linearly changed from 8 sccm to 40 sccm over time, the temperature is 650~700℃, and the time is 30~45 min.

10. A cutting tool having a composite self-lubricating coating comprising a substrate and a coating, characterised in that, The coating is the composite self-lubricating coating for a cutter according to any one of claims 1~8.

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