Coating for coating cutting tool and preparation method thereof

Abstract

The invention relates to a coating for coating a cutting tool and a preparation method thereof.The coating for coating the cutting tool comprises a first film layer, a second film layer and a third film layer which are sequentially arranged in a stacked mode in the direction away from the cutting tool; the first film layer comprises a plurality of A1 layers and A2 layers which are alternately stacked, the A1 layers comprise Al < 1-a > CraN, a is larger than or equal to 0.3 and smaller than or equal to 0.5, the A2 layers comprise Al < 1-b > TibN, and b is larger than or equal to 0.33 and smaller than or equal to 0.5; the second film layer comprises a plurality of B1 layers and B2 layers which are alternately stacked, the B1 layers comprise Al < 1-a > CraN, a is larger than or equal to 0.3 and smaller than or equal to 0.5, the B2 layers comprise Ti < 1-c > SicN, c is larger than or equal to 0.05 and smaller than or equal to 0.25, and the B1 layers make contact with the first film layer; the third film layer comprises Ti1-cSicN, and c is more than or equal to 0.05 and less than or equal to 0.25; the thickness of the first film layer is T1, the thickness of the second film layer is T2, the thickness of the third film layer is T3, and T2 > T1 > T3. According to the coating provided by the invention, the interface bonding force between internal film layers is high, the stress matching between the layers is good, and the overall toughness of the coating is high.

Description

Technical Field

[0001] This application relates to the field of coating cutting tools, and in particular to coatings for coating cutting tools and methods for preparing them. Background Technology

[0002] With the development of the machinery industry, more and more engineering materials with high hardness, high wear resistance and difficult cutting have been developed, which has led to increased wear of cutting tools for processing these materials. Therefore, researchers have developed a series of hard coating materials, such as AlTiN, AlCrN, TiSiN, etc.

[0003] Traditionally, a single hard coating or a multilayer structure consisting of simple stacking of different hard coatings is often used. However, a single AlTiN coating has the problem of insufficient oxidation resistance temperature; a single AlCrN coating has the problem of insufficient thermal stability; a single TiSiN coating has the technical problem of high brittleness and insufficient bonding strength with the substrate; and a multilayer structure consisting of simple stacking of different hard coatings has the problems of poor interfacial bonding, poor interlayer stress matching, and insufficient overall toughness of the coating. Summary of the Invention

[0004] Based on this, this application provides a coating for covering cutting tools and a method for preparing the same. The coating for covering cutting tools has high interfacial bonding between inner film layers, good interlayer stress matching, and strong overall toughness.

[0005] The first aspect of this application provides a coating for covering a cutting tool, comprising a first film layer, a second film layer, and a third film layer stacked sequentially in a direction away from the cutting tool;

[0006] The first film layer comprises multiple alternating layers A1 and A2, wherein the A1 layer comprises Al 1-a Cr a N, 0.3≤a≤0.5, layer A2 includes Al 1-b Ti b N, 0.33≤b≤0.5;

[0007] The second film layer comprises multiple alternating layers B1 and B2, wherein layer B1 comprises Al. 1-a Cr a N, 0.3≤a≤0.5, B2 layer includes Ti 1-c Si c N, 0.05≤c≤0.25, B1 layer is in contact with the first film layer;

[0008] The third film layer includes Ti. 1-c Si c N, 0.05 ≤ c ≤ 0.25;

[0009] The thickness of the first film layer is T1, the thickness of the second film layer is T2, and the thickness of the third film layer is T3, satisfying: T2>T1>T3.

[0010] In some embodiments, the coating covering the cutting tool satisfies at least one of the following conditions:

[0011] (1)0.5μm≤T1≤1.5μm;

[0012] (2)1.0μm≤T2≤3.0μm;

[0013] (3)0.2μm≤T3<1.5μm.

[0014] In some implementations, the thickness of the A1 layer is 10 nm to 200 nm.

[0015] In some implementations, the thickness of the A2 layer is 10 nm to 200 nm.

[0016] In some implementations, the thickness of the B1 layer is 1 nm to 50 nm.

[0017] In some implementations, the thickness of the B2 layer is 1 nm to 50 nm.

[0018] In some embodiments, the coating further includes a substrate layer disposed between the cutting tool and the first film layer, the substrate layer comprising a nitride containing Ti and / or Cr.

[0019] In some implementations, the thickness of the substrate layer is 0.01 μm to 0.5 μm.

[0020] The second aspect of this application provides a method for preparing a coating for a cutting tool, comprising the following steps:

[0021] Under a nitrogen atmosphere, AlCr alloy target and AlTi alloy target are alternately evaporated multiple times using cathodic arc ion plating to form the first film layer on the cutting tool.

[0022] Under a nitrogen atmosphere, AlCr alloy target and TiSi alloy target are alternately evaporated multiple times using cathodic arc ion plating to form a second film layer on the first film layer.

[0023] Under a nitrogen atmosphere, the TiSi alloy target material is evaporated using a cathodic arc ion plating method to form a third film layer on the second film layer.

[0024] In some embodiments, prior to the step of forming the first film layer on the cutting tool, the method further includes: forming a base layer on the surface of the cutting tool under a nitrogen atmosphere using a cathodic arc ion plating method, the base layer comprising a nitride containing Ti and / or Cr.

[0025] Compared with traditional technologies, this application has at least the following beneficial effects:

[0026] This application achieves a gradient multilayer interface design with a tough inner layer and a hard outer layer by sequentially stacking a first film layer, a second film layer, and a third film layer of specific components along a direction away from the cutting tool. The three-layer structure works synergistically to improve the interfacial bonding force between the film layers, ensure a smooth transition of stress between each layer, guarantee stress matching between layers, and enhance the overall toughness of the coating.

[0027] Specifically, the first film layer in contact with the cutting tool is a multilayer structure consisting of alternating AlCrN and AlTiN layers. This structure effectively refines the coating grains and inhibits the growth of coarse columnar crystals. On the one hand, the first film layer can buffer the stress between the cutting tool and the second film layer, improving the bonding strength between the coating and the cutting tool. On the other hand, it absorbs or buffers the impact energy received by the cutting tool during the cutting process, improving the overall toughness and impact resistance of the coating. This provides a strong and tough support foundation for the outer film layer and inhibits problems such as peeling and cracking of the outer film layer due to stress concentration or impact load.

[0028] The second film layer, located in the middle of the coating, is a nano-multilayer structure consisting of alternating AlCrN and TiSiN layers. It serves to support the first and third film layers. On the one hand, this film layer provides support for the hard and brittle third film layer and provides a large number of dense interfaces, inhibiting the propagation of cracks that originate on the surface of the third film layer inward, improving the coating's resistance to cracking and peeling, and extending the life of cutting tools. On the other hand, this film layer protects the first film layer, preventing it from directly bearing surface mechanical stress and thermal load.

[0029] The outermost third film layer is a TiSiN film layer, which has extremely high hardness, excellent wear resistance and oxidation resistance. As the coating surface that is in direct contact with the workpiece, it provides the first line of wear resistance for the cutting tool, effectively resisting abrasive wear and diffusion wear, and its performance is stable, especially at high temperatures.

[0030] This application sets the thickness of the second film layer (T2) to be greater than that of the first film layer (T1) and then to the thickness of the third film layer (T3). The third film layer, which has the highest hardness, stress, and brittleness, is made thinner, fully utilizing its high wear resistance while minimizing the negative impacts of its high stress and brittleness. The second film layer, which bears the main responsibility for wear resistance and crack resistance, is made the thickest, ensuring the coating's wear resistance and durability. The thickness of the first film layer, which provides toughness and adhesion, is positioned between the thicknesses of the second and third film layers, ensuring effective buffering while avoiding increased coating stress due to excessive thickness. Through the balanced matching of the three film layer thicknesses, the coating exhibits a gradient multi-layer interface design with an inner toughness and an outer hardness, ensuring the coating possesses high bonding strength, high toughness, high wear resistance, and long service life. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of the coating covering the cutting tool in Embodiment 1 of this application.

[0033] Figure 2 This is a schematic diagram of the structure of the coating covering the cutting tool in Embodiment 2 of this application.

[0034] Figure 3 This is a schematic diagram of the structure of the coating covering the cutting tool in Embodiment 3 of this application.

[0035] Figure 4 This is a schematic diagram of a method for preparing a coating for covering a cutting tool according to an embodiment of this application.

[0036] Figure 5 This is a schematic diagram of a cathode arc evaporation apparatus according to one embodiment of this application.

[0037] Explanation of reference numerals in the attached figures

[0038] 1. Coating for the cutting tool; 10. First film layer; 20. Second film layer; 30. Third film layer; 40. Substrate layer;

[0039] 2. Cathode arc evaporation device; 100. Shell; 200. Chamber; 300. Workpiece turntable; 400. Fixture; 500. Cathode evaporation source; 600. Vacuum pump. Detailed Implementation

[0040] A detailed reference is now provided to embodiments of this application, one or more of which are described below. Each embodiment is provided for explanation and not for limitation. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to this application without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0041] Therefore, this application is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of this application are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of this application.

[0042] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0043] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0044] Unless otherwise specified herein, all embodiments and optional embodiments of this application can be combined with each other to form new technical solutions. Similarly, all technical features and optional technical features of this application can be combined with each other to form new technical solutions.

[0045] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0046] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0047] Unless otherwise stated or in case of conflict, the terms or phrases used in this application shall have the following meanings:

[0048] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" or "at least one" means one or more of two.

[0049] In this application, terms such as "further" and "especially" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0050] In this application, when numerical intervals (i.e., numerical ranges) are mentioned, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0051] like Figure 1-3 As shown, the first aspect of this application provides a coating 1 for covering a cutting tool, comprising a first film layer 10, a second film layer 20, and a third film layer 30 sequentially stacked along a direction away from the cutting tool. The first film layer 10 includes multiple alternating layers A1 and A2, wherein the A1 layer includes Al... 1-a Cr a N, 0.3≤a≤0.5, layer A2 includes Al 1-b Ti b N, 0.33≤b≤0.5; the second film layer 20 includes multiple alternating layers B1 and B2, wherein layer B1 includes Al 1- a Cr a N, 0.3≤a≤0.5, B2 layer includes Ti 1-c Si c N, 0.05≤c≤0.25, B1 layer is in contact with the first film layer 10; the third film layer 30 includes Ti 1-c Si c N, 0.05≤c≤0.25; the thickness of the first film layer 10 is T1, the thickness of the second film layer 20 is T2, and the thickness of the third film layer 30 is T3, satisfying: T2>T1>T3.

[0052] It should be noted that in this application, Al1-a Cr a In N, 'a' represents the atomic ratio of Cr relative to the total amount of Al and Cr; Al 1-b Ti b In N, b represents the atomic ratio of Ti relative to the total amount of Al and Ti; Ti 1-c Si c In N, c represents the atomic ratio of Si relative to the total amount of Ti and Si.

[0053] This application achieves a gradient multilayer interface design with a tough inner layer and a hard outer layer by sequentially stacking a first film layer 10, a second film layer 20, and a third film layer 30 of specific components along a direction away from the cutting tool. The three-layer structure works synergistically to improve the interfacial bonding force between the film layers, ensure a smooth transition of stress between each layer, guarantee stress matching between layers, and enhance the overall toughness of the coating.

[0054] Specifically, the first film layer 10 in contact with the cutting tool is a multilayer structure consisting of alternating AlCrN and AlTiN layers. This structure effectively refines the coating grains and inhibits the growth of coarse columnar crystals. On the one hand, the first film layer 10 can buffer the stress between the cutting tool and the second film layer 20, improving the bonding strength between the coating and the cutting tool. On the other hand, it absorbs or buffers the impact energy received by the cutting tool during the cutting process, improving the overall toughness and impact resistance of the coating. This provides a strong and tough support foundation for the outer film layer and inhibits problems such as peeling and cracking of the outer film layer due to stress concentration or impact load.

[0055] The second film layer 20, located in the middle of the coating, is a nano-multilayer structure with alternating AlCrN and TiSiN layers. It serves to support the first film layer 10 and the third film layer 30. On the one hand, this film layer provides support for the hard and brittle third film layer 30 and provides a large number of dense interfaces, inhibiting the propagation of cracks that originate on the surface of the third film layer 30 into the interior, improving the coating's resistance to cracking and peeling, and extending the life of the cutting tool. On the other hand, this film layer protects the first film layer 10, preventing it from directly bearing surface mechanical stress and thermal load.

[0056] The outermost third film layer 30 is a TiSiN film layer, which has extremely high hardness, excellent wear resistance and oxidation resistance. As the coating surface that is in direct contact with the workpiece, it provides the first line of wear resistance for the cutting tool, effectively resisting abrasive wear and diffusion wear, and its performance is stable, especially at high temperatures.

[0057] This application sets the thickness of the second film layer 20 (T2) > the thickness of the first film layer 10 (T1) > the thickness of the third film layer 30 (T3). The third film layer 30, which has the highest hardness, stress, and brittleness, is made thinner, fully utilizing its high wear resistance while minimizing the negative impacts of its high stress and brittleness. The second film layer 20, which bears the main responsibility for wear resistance and crack resistance, is made the thickest, ensuring the coating's wear resistance and durability. The thickness of the first film layer 10, which provides toughness and adhesion, is placed between the thicknesses of the second and third film layers 30, ensuring effective buffering while avoiding increased coating stress due to excessive thickness. Through the balanced matching of the three film layer thicknesses, the coating exhibits a gradient multi-layer interface design with an inner toughness and an outer hardness, ensuring the coating possesses high bonding strength, high toughness, high wear resistance, and long service life.

[0058] It is understood that the cutting tools in this application may be drills, end mills, indexable inserts for milling, indexable inserts for turning, metal saws, gear cutting tools, reamers, or taps.

[0059] In some embodiments, the A1 layer in the first film layer 10 is in contact with the cutting tool, that is, along the direction away from the cutting tool, the first film layer 10 is stacked alternately in the manner of A1 layer, A2 layer...A1 layer, A2 layer.

[0060] In some embodiments, the A2 layer in the first film layer 10 is in contact with the cutting tool, that is, along the direction away from the cutting tool, the first film layer 10 is stacked alternately in the manner of A2 layer, A1 layer...A2 layer, A1 layer.

[0061] In some embodiments, in the coating 1 covering the cutting tool, the thickness T1 of the first film layer 10 is 0.5μm to 1.5μm, including 0.5μm, 0.8μm, 1μm, 1.2μm, and 1.5μm.

[0062] If the thickness of the first film layer 10 is insufficient, it will be difficult for the film layer to buffer and absorb impact vibration energy during the cutting process, which will easily lead to the coating peeling off from the surface of the cutting tool. If the first film layer 10 is too thick, it will easily lead to excessive coating stress, which will also easily cause the coating to peel off from the surface of the cutting tool. Therefore, this application controls the thickness of the first film layer 10 to be between 0.5 μm and 1.5 μm, so as to buffer and absorb impact vibration energy while avoiding excessive coating stress.

[0063] In some embodiments, the thickness of any Al layer in the first film layer 10 is 10nm to 200nm, including 10nm, 50nm, 100nm, 150nm, and 200nm. Further, the thickness of any Al layer is 30nm to 70nm.

[0064] In some embodiments, the thickness of any A2 layer in the first film layer 10 is 10nm to 200nm, including 10nm, 50nm, 100nm, 150nm, and 200nm. Further, the thickness of any A2 layer is 30nm to 70nm.

[0065] If the thickness of layers A1 and A2 is insufficient, the resulting nano-multilayer structure will cause significant internal stress within the first film layer 10; if the thickness of layers A1 and A2 is too large, the formation of columnar crystals in the film layer cannot be effectively suppressed, resulting in insufficient coating toughness. Therefore, this application controls the thickness of layer A1 to 10 nm to 200 nm and the thickness of layer A2 to 10 nm to 200 nm.

[0066] In some embodiments, in the coating 1 covering the cutting tool, the thickness T2 of the second film layer 20 is 1.0 μm to 3.0 μm, including 1.0 μm, 1.2 μm, 1.5 μm, 2 μm, 2.5 μm, and 3.0 μm.

[0067] In some embodiments, the thickness of any B1 layer in the second film layer 20 is 1 nm to 50 nm, including 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, and 50 nm. Further, the thickness of any B1 layer is 5 nm to 20 nm.

[0068] In some embodiments, the thickness of any B2 layer in the second film layer 20 is 1 nm to 50 nm, including 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, and 50 nm. Further, the thickness of any B2 layer is 5 nm to 20 nm.

[0069] This application improves the hardness of the coating by setting a multi-layered second film layer 20, thereby suppressing coating cracking and defects and extending the service life of cutting tools. Specifically, on the one hand, the lattice mismatch and interfacial stress generated by layers B1 and B2 are used to suppress dislocation movement, producing a "Hall-Petch effect," which enables the second film layer 20 to achieve a hardness exceeding 40 GPa, thus improving the wear resistance of the coating. On the other hand, during the cutting process, when cracks occur on the coating surface, the interface of the second film layer 20 can suppress crack propagation. This, in turn, improves the hardness of the coating, suppresses coating cracking and defects, and extends the service life of the cutting tool.

[0070] In some embodiments, in the coating 1 covering the cutting tool, the thickness T3 of the third film layer 30 satisfies 0.2μm≤T3<1.5μm.

[0071] In some embodiments, the coating further includes a substrate layer 40 disposed between the cutting tool and the first film layer 10, the substrate layer 40 comprising a nitride containing Ti and / or Cr. The substrate layer 40 is disposed between the cutting tool and the first film layer 10 to improve the adhesion of the coating to the surface of the cutting tool.

[0072] For example, the nitride of Ti is TiN, and the nitride of Cr is CrN.

[0073] In some embodiments, the thickness of the substrate 40 is 0.01 μm to 0.5 μm, including 0.01 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, and 0.5 μm.

[0074] like Figure 4 As shown, a second aspect of this application provides a method for preparing a coating 1 covering a cutting tool, comprising the following steps:

[0075] S1. Under a nitrogen atmosphere, AlCr alloy target and AlTi alloy target are alternately evaporated multiple times using cathodic arc ion plating to form the first film layer 10 on the cutting tool.

[0076] S2. Under a nitrogen atmosphere, AlCr alloy target and TiSi alloy target are alternately evaporated multiple times using cathodic arc ion plating to form a second film layer 20 on the first film layer 10.

[0077] S3. Under a nitrogen atmosphere, the TiSi alloy target material is evaporated by cathodic arc ion plating to form a third film layer 30 on the second film layer 20.

[0078] In some embodiments, the step of forming the first film layer 10 on the cutting tool is further included before:

[0079] S0. Under a nitrogen atmosphere, a base layer 40 is formed on the surface of the cutting tool using a cathodic arc ion plating method. The base layer 40 includes nitrides containing Ti and / or Cr.

[0080] In some embodiments, prior to S1, a pretreatment step of the cutting tool is included: ion bombardment treatment of the cutting tool surface using a cathodic arc evaporation metal target method to improve the bonding strength between the cutting tool and the coating.

[0081] like Figure 5 As shown, this application also provides a cathode arc evaporation apparatus 2 for implementing the preparation method provided in the second aspect of this application.

[0082] The cathode arc evaporation apparatus 2 includes a housing 100, a chamber 200, a workpiece rotating frame 300, a clamp 400, a cathode evaporation source 500, a bias power supply, a heater, a vacuum pump 600, and a gas supply unit. The chamber 200 is located inside the housing 100. The workpiece rotating frame 300 is located within the chamber 200 and can rotate clockwise or counterclockwise. The clamp 400 is mounted on the workpiece rotating frame 300 to hold a cutting tool, and the clamp 400 can rotate on its own axis while the workpiece rotating frame 300 is rotating. Several cathode evaporation sources 500 are located within the chamber 200 for mounting target materials. The bias power supply is located within the chamber 200 for applying a bias voltage to the cutting tool. The heater is located within the chamber 200 for heating the cutting tool. The vacuum pump 600 is located outside the housing 100 and connected to the chamber 200 for evacuating the chamber 200. A gas supply unit is located outside the housing 100 and connected to the chamber 200 for supplying process gases (such as nitrogen, argon, etc.) to the chamber 200.

[0083] The implementation schemes of this application will be described in detail below with reference to specific embodiments. It should be understood that these embodiments are only for illustrating this application and are not intended to limit the scope of this application. For experimental methods in the following embodiments where specific conditions are not specified, the guidance given in this application should be followed first, or experimental manuals or conventional conditions in the art can be used, or conditions recommended by the manufacturer can be used, or experimental methods known in the art can be referenced. Unless otherwise specified, the raw materials used in the following experiments can all be routinely purchased from the market.

[0084] Example 1

[0085] The chamber 200 is evacuated to a vacuum using a vacuum pump 600. The heater is then turned on to heat the cutting tool. A bias voltage is then applied to the cutting tool so that Ar ions or metal ions from the target material on the cathode evaporation source 500 clean the cutting tool.

[0086] When the cathode evaporation source 500, equipped with AlCr and AlTi metal targets, is in operation, when the cutting tool rotates to the AlCr metal target attachment, under the action of a bias voltage, the Al and Cr ions evaporated and ionized from the AlCr metal target surface move to the cutting tool surface and react with N ions to form an Al layer on the cutting tool. When the cutting tool rotates to the AlTi metal target attachment, under the action of a bias voltage, the Al and Ti ions evaporated and ionized from the AlTi metal target surface move to the cutting tool surface and react with N ions to form an A2 layer on the cutting tool. After the AlCr and AlTi metal targets alternate and repeat multiple times, a first film layer 10 is formed on the surface of the cutting tool. The A1 layer is composed of Al... 0.70 Cr 0.30 The N layer is 70nm thick, and the A2 layer is Al.0.67 Ti 0.33 N has a thickness of 30 nm, the first film 10 has a thickness of 1.5 μm, and the number of layers is 15.

[0087] Next, with the cathode evaporation source 500, equipped with AlCr and TiSi metal targets, in operation, when the cutting tool rotates to the AlCr metal target attachment, under the action of a bias voltage, the Al and Cr ions evaporated and ionized from the AlCr metal target surface move to the cutting tool surface and react with N ions to form a B1 layer on the cutting tool. When the cutting tool rotates to the TiSi metal target attachment, under the action of a bias voltage, the Ti and Si ions evaporated and ionized from the TiSi metal target surface move to the cutting tool surface and react with N ions to form a B2 layer on the cutting tool. After the AlCr and TiSi metal targets alternately and repeatedly operate multiple times, a second film layer 20 is formed on the surface of the first film layer 10. The B1 layer is Al... 0.70 Cr 0.30 The N layer is 5nm thick, and the B2 layer is Ti. 0.80 Si 0.20 The N layer has a thickness of 20 nm, the second film 20 has a thickness of 2.5 μm, and the number of layers is 100.

[0088] Finally, with the cathode evaporation source 500 equipped with the TiSi metal target turned on, when the cutting tool rotates to the vicinity of the TiSi metal target, under the action of the bias voltage, the Ti and Si ions that have evaporated and ionized from the surface of the TiSi metal target move to the surface of the cutting tool and react with N ions to form a third film layer 30 on the second film layer 20, thus obtaining the coating 1 covering the cutting tool. The third film layer 30 is Ti... 0.80 Si 0.20 The N layer has a thickness of 0.35 μm.

[0089] Example 2

[0090] The preparation process of this embodiment is basically the same as that of Embodiment 1. The main difference is that in this embodiment, the A2 layer is formed first and then the A1 layer is formed in the first film layer 10.

[0091] Example 3

[0092] The preparation process of this embodiment is basically the same as that of Embodiment 1. The main difference is that this embodiment includes the following steps before forming the first film layer 10:

[0093] When the cathode arc evaporation source with a Cr metal target is turned on, when the cutting tool rotates to a position near the Cr metal target, under the action of the bias voltage, the metal Cr ions that evaporate and ionize from the surface of the metal target move to the surface of the cutting tool and react with N ions to form a CrN substrate layer 40 on the cutting tool. The thickness of the substrate layer 40 is 0.3 μm.

[0094] Example 4

[0095] The preparation process of this embodiment is basically the same as that of embodiment 3. The main difference is that a TiN substrate layer 40 is formed on the cutting tool in this embodiment.

[0096] Example 5

[0097] The preparation process of this embodiment is basically the same as that of embodiment 3. The main difference is that the thickness of the base layer 40 in this embodiment is 0.01 μm.

[0098] Example 6

[0099] The preparation process of this embodiment is basically the same as that of embodiment 3. The main difference is that the thickness of the base layer 40 in this embodiment is 0.5 μm.

[0100] Example 7

[0101] The preparation process of this embodiment is basically the same as that of Embodiment 3, the main difference being that the A1 layer and B1 layer in this embodiment are Al 0.59 Cr 0.41 The N layer, B2 layer, and third film layer 30 are Ti. 0.85 Si 0.15 N layers.

[0102] Example 8

[0103] The preparation process of this embodiment is basically the same as that of Embodiment 3, the main difference being that the A1 layer and B1 layer in this embodiment are Al 0.52 Cr 0.48 The N layer, B2 layer, and third film layer 30 are Ti. 0.78 Si 0.22 N layers.

[0104] Example 9

[0105] The preparation process of this embodiment is basically the same as that of Embodiment 3, the main difference being that the A2 layer in this embodiment is Al. 0.55 Ti 0.45 N layers.

[0106] Example 10

[0107] The preparation process of this embodiment is basically the same as that of Embodiment 3, the main difference being that the A2 layer in this embodiment is Al. 0.5 Ti 0.5 N layers.

[0108] Example 11

[0109] The preparation process of this embodiment is basically the same as that of Embodiment 3. The main difference is that the B2 layer and the third film layer 30 in this embodiment are Ti. 0.95 Si 0.05 N layers.

[0110] Example 12

[0111] The preparation process of this embodiment is basically the same as that of embodiment 3. The main difference is that the thickness of layer A1 is 30 nm, the thickness of layer A2 is 70 nm, the thickness of the first film layer 10 is 1.5 μm, and the number of layers is 15.

[0112] Example 13

[0113] The preparation process of this embodiment is basically the same as that of embodiment 3. The main difference is that the thickness of layer B1 is 5 nm, the thickness of layer B2 is 5 nm, the thickness of the second film layer 20 is 2.5 μm, and the number of layers is 250.

[0114] Example 14

[0115] The preparation process of this embodiment is basically the same as that of embodiment 3. The main difference is that the thickness of layer B1 is 20 nm, the thickness of layer B2 is 5 nm, the thickness of the second film layer 20 is 2.5 μm, and the number of layers is 100.

[0116] Example 15

[0117] The preparation process of this embodiment is basically the same as that of embodiment 3. The main difference is that the thickness of layer A1 is 250 nm, the thickness of layer A2 is 250 nm, the thickness of the first film layer 10 is 1.5 μm, and the number of layers is 3.

[0118] Example 16

[0119] The preparation process of this embodiment is basically the same as that of embodiment 3. The main difference is that the thickness of layer A1 is 7 nm, the thickness of layer A2 is 8 nm, the thickness of the first film layer 10 is 1.5 μm, and the number of layers is 100.

[0120] Example 17

[0121] The preparation process of this embodiment is basically the same as that of embodiment 3. The main difference is that the thickness of layer B1 is 60 nm, the thickness of layer B2 is 65 nm, the thickness of the second film layer 20 is 2.5 μm, and the number of layers is 20.

[0122] Example 18

[0123] The preparation process of this embodiment is basically the same as that of embodiment 3. The main difference is that the thickness of the first film layer 10 is 0.5 μm, the thickness of the second film layer 20 is 1 μm, and the thickness of the third film layer 30 is 0.2 μm.

[0124] Example 19

[0125] The preparation process of this embodiment is basically the same as that of embodiment 3. The main difference is that the thickness of the first film layer 10 is 1.5 μm, the thickness of the second film layer 20 is 3 μm, and the thickness of the third film layer 30 is 1.4 μm.

[0126] Comparative Example 1

[0127] The coating in this comparative example includes a CrN layer (0.35 μm) and an Al layer sequentially stacked along the direction away from the cutting tool. 0.70 Cr 0.30 N layer (1.05μm), Al 0.67 Ti 0.33 N layer (0.45μm), Al 0.70 Cr 0.30 N layer (0.5μm) and Ti 0.80 Si 0.20 N layer (2.35μm).

[0128] Comparative Example 2

[0129] The preparation process of this comparative example is basically the same as that of Example 3. The main difference is that the thickness of the first film layer 10 in this comparative example is 1.5 μm, the thickness of the second film layer 20 is 1 μm, and the thickness of the third film layer 30 is 0.35 μm.

[0130] Table 1

[0131]

[0132] Continued from Table 1

[0133]

[0134] Test case

[0135] Cutting tests were conducted on the cutting tools prepared in the above embodiments and comparative examples. The material used for cutting was SKD11 with a hardness of 62 HRC after heat treatment, and the machining method was side cutting with oil mist cooling. A 6mm outer diameter end mill (cutting tool) was used. The machine tool spindle speed was 3500 r / min, feed rate was 650 mm / min, width at cut was 0.07 mm, depth at cut was 1.2 mm, and cutting time was 60 min. The coating performance was evaluated by comparing the flank wear of the tools with different coating schemes after cutting. The cutting test results are shown in Table 2 below.

[0136] Table 2

[0137]

[0138] As shown in Table 2, compared with Comparative Examples 1 and 2, under the same cutting tool substrate and cutting conditions, the cutting tool coated with the coating provided in this application has higher wear resistance and high-temperature oxidation resistance.

[0139] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0140] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A coating for covering cutting tools, characterized in that, Along a direction away from the cutting tool, it includes a first film layer, a second film layer, and a third film layer stacked sequentially; The first film layer comprises multiple alternating layers A1 and A2, wherein the A1 layer comprises Al 1-a Cr a N, 0.3≤a≤0.5, the A2 layer includes Al 1-b Ti b N, 0.33≤b≤0.5; The second film layer comprises multiple alternating layers B1 and B2, wherein the B1 layer comprises Al 1-a Cr a N, 0.3 ≤ a ≤ 0.5, the B2 layer includes Ti 1-c Si c N, 0.05≤c≤0.25, wherein layer B1 is in contact with the first film layer; The third film layer includes Ti. 1-c Si c N, 0.05 ≤ c ≤ 0.25; The thickness of the first film layer is T1, the thickness of the second film layer is T2, and the thickness of the third film layer is T3, satisfying: T2 > T1 > T3.

2. The coating for covering cutting tools according to claim 1, characterized in that, At least one of the following conditions must be met: (1)0.5μm≤T1≤1.5μm; (2)1.0μm≤T2≤3.0μm; (3)0.2μm≤T3<1.5μm.

3. The coating for covering cutting tools according to claim 1, characterized in that, The thickness of the A1 layer is 10nm~200nm.

4. The coating for covering cutting tools according to claim 1, characterized in that, The thickness of the A2 layer is 10nm~200nm.

5. The coating for covering cutting tools according to claim 1, characterized in that, The thickness of the B1 layer is 1 nm to 50 nm.

6. The coating for covering cutting tools according to claim 1, characterized in that, The thickness of the B2 layer is 1nm to 50nm.

7. The coating for covering cutting tools according to any one of claims 1 to 6, characterized in that, The coating further includes a substrate layer disposed between the cutting tool and the first film layer, the substrate layer comprising a nitride containing Ti and / or Cr.

8. The coating for covering cutting tools according to claim 7, characterized in that, The thickness of the substrate layer is 0.01μm to 0.5μm.

9. A method for preparing a coating for covering a cutting tool, characterized in that, Includes the following steps: Under a nitrogen atmosphere, AlCr alloy target and AlTi alloy target are alternately evaporated multiple times using cathodic arc ion plating to form the first film layer on the cutting tool. Under a nitrogen atmosphere, AlCr alloy target and TiSi alloy target are alternately evaporated multiple times using cathodic arc ion plating to form a second film layer on the first film layer. Under a nitrogen atmosphere, the TiSi alloy target is evaporated using a cathode arc ion plating method to form a third film layer on the second film layer.

10. The preparation method according to claim 9, characterized in that, Before the step of forming the first film layer on the cutting tool, the method further includes: forming a base layer on the surface of the cutting tool under a nitrogen atmosphere using a cathodic arc ion plating method, the base layer comprising a nitride containing Ti and / or Cr.

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