Cutting tool

Abstract

A cutting tool includes a base material and a coating disposed on the base material. The coating includes a first layer. The first layer is composed of alternating layers in which a first unit layer and a second unit layer are alternately stacked. The first unit layer includes AlaTi(1-a-b)SibN. The second unit layer includes AlcCr(1-c-d)CudN. The a, b, c, and d satisfy 0.50 ≤ a ≤ 0.75, 0.005 ≤ b ≤ 0.20, 0.50 ≤ c ≤ 0.85, and 0.005 ≤ d < 0.10. The average thickness of the first unit layer is 2 nm to 50 m, and the average thickness of the second unit layer is 2 nm to 50 m.

Description

cutting tools

[0001] The present disclosure relates to cutting tools.

[0002] Conventionally, cutting tools including a substrate and a coating disposed on the substrate have been used in cutting processes (Patent Document 1).

[0003] WO 2006 / 070730

[0004] [Correction based on Rule 91 11.11.2024] The present disclosure provides a cutting tool comprising a substrate and a coating disposed on the substrate, wherein the coating includes a first layer, the first layer being composed of alternating layers in which first unit layers and second unit layers are alternately stacked, and the first unit layer is made of Al ａ Ti （１－ａ－ｂ） Si ｂ N, and the second unit layer is made of Al ｃ Cr （１－ｃ－ｄ） Cu ｄ N, wherein the a, the b, the c, and the d satisfy 0.50≦a≦0.75, 0.005≦b≦0.20, 0.50≦c≦0.85, and 0.005≦d<0.10, the average thickness of the first unit layer is 2 nm or more and 50 nm or less, and the average thickness of the second unit layer is 2 nm or more and 50 nm or less.

[0005] FIG. 1 is a schematic enlarged cross-sectional view of an example of a cutting tool according to Embodiment 1. FIG. 2 is a schematic enlarged cross-sectional view of an example of a cutting tool according to Embodiment 1. FIG. 3 is a schematic enlarged cross-sectional view of an example of a cutting tool according to Embodiment 1. FIG. 4 is a schematic enlarged cross-sectional view of an example of a cutting tool according to Embodiment 1. FIG. 5 is a diagram for explaining an example of a thickness ratio between a first unit layer and a second unit layer. FIG. 6 is a schematic cross-sectional view of a cathodic arc ion plating apparatus used in the examples. FIG. 7 is a schematic top view of the cathodic arc ion plating apparatus shown in FIG. 6.

[0006] [Problem to be Solved by the Present Disclosure] In recent years, work materials have become more diverse, and particularly in the fields of aircraft and medicine, cutting of nickel-based alloys, which are known as difficult-to-cut materials, is on the rise. When nickel-based alloys are continuously machined using cutting tools, the cutting edge temperature becomes high, shortening the life of the cutting tool. Therefore, there is a demand for cutting tools that can have a long tool life, especially when machining nickel-based alloys with high efficiency.

[0007] Therefore, an object of the present disclosure is to provide a cutting tool that can have a long tool life even when machining nickel-based alloys with high efficiency.

[0008] Effect of the Present Disclosure According to the present disclosure, it is possible to provide a cutting tool that can have a long tool life, particularly in high-efficiency machining of nickel-based alloys.

[0009] [Correction based on Rule 91 11.11.2024] [Explanation of the embodiment of the present disclosure] First, the embodiment of the present disclosure will be listed and explained. (1) A cutting tool of the present disclosure is a cutting tool including a substrate and a coating disposed on the substrate, wherein the coating includes a first layer, and the first layer is composed of alternating layers in which first unit layers and second unit layers are alternately stacked, and the first unit layer is Al ａ Ti （１－ａ－ｂ） Si ｂ N, and the second unit layer is made of Al ｃ Cr （１－ｃ－ｄ） Cu ｄ N, wherein the a, the b, the c, and the d satisfy 0.50≦a≦0.75, 0.005≦b≦0.20, 0.50≦c≦0.85, and 0.005≦d<0.10, the average thickness of the first unit layer is 2 nm or more and 50 nm or less, and the average thickness of the second unit layer is 2 nm or more and 50 nm or less.

[0010] According to the present disclosure, it is possible to provide a cutting tool that can have a long tool life, particularly in high-efficiency machining of nickel-based alloys.

[0011] (2) In the above (1), the b and d may satisfy the relationship b / d ≥ 1. This further improves the tool life.

[0012] (3) In the above (1) or (2), the ratio λ1 / λ2 of the thickness λ1 of the first unit layer to the thickness λ2 of the second unit layer in the first unit layer and the second unit layer adjacent to the first unit layer may be greater than 1.0, which further improves the tool life.

[0013] (4) In any one of the above (1) to (3), the thickness of the first layer may be 0.5 μm or more and 10 μm or less, thereby further improving the tool life.

[0014] (5) In any of the above (1) to (4), the coating may further include a second layer provided between the substrate and the first layer, and the second layer may be made of at least one element selected from a first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum, and silicon of the periodic table, or a first compound consisting of at least one element selected from the first group and at least one element selected from a second group consisting of carbon, nitrogen, oxygen, and boron.

[0015] This further improves the tool life.

[0016] (6) In any of the above (1) to (5), the coating may further include a third layer disposed on the first layer opposite the substrate, and the third layer may be made of at least one element selected from a first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum, and silicon of the periodic table, or a second compound consisting of at least one element selected from the first group and at least one element selected from a second group consisting of carbon, nitrogen, oxygen, and boron.

[0017] This further improves the tool life.

[0018] (7) In any one of the above (1) to (6), the thickness of the coating may be 0.5 μm or more and 12 μm or less, thereby further improving the tool life.

[0019] (8) In any of the above (1) to (7), the substrate may be made of cemented carbide, cermet, cubic boron nitride sintered body, diamond sintered body, high-speed steel, or ceramics, which further improves the tool life.

[0020] [Details of the Embodiments of the Present Disclosure] Specific examples of cutting tools according to the present disclosure will be described below with reference to the drawings. In the drawings of the present disclosure, the same reference numerals represent the same or corresponding parts. Furthermore, dimensional relationships such as length, width, thickness, and depth have been appropriately changed for clarity and simplification of the drawings, and do not necessarily represent actual dimensional relationships.

[0021] In the present disclosure, the notation in the form of "A to B" means the upper and lower limits of a range (i.e., A or more and B or less), and when no unit is specified for A and a unit is specified only for B, the units of A and B are the same.

[0022] In the present disclosure, when a compound or the like is represented by a chemical formula, unless the atomic ratio is particularly limited, it is intended to include any conventionally known atomic ratio, and should not necessarily be limited to only those within the stoichiometric range.

[0023] In the present disclosure, when one or more numerical values ​​are listed as the lower limit and the upper limit of a numerical range, the combination of any one numerical value listed as the lower limit and any one numerical value listed as the upper limit is also considered to be disclosed.

[0024] [Correction based on Rule 91 11.11.2024] [Embodiment 1: Cutting Tool] As shown in FIGS. 1 to 4 , a cutting tool according to one embodiment of the present disclosure (hereinafter also referred to as “Embodiment 1”) is a cutting tool 1 including a substrate 2 and a coating 3 disposed on the substrate 2, wherein the coating 3 includes a first layer 13, the first layer 13 being composed of alternating layers in which first unit layers 12 and second unit layers 15 are alternately stacked, and the first unit layer 12 is made of Al ａ Ti （１－ａ－ｂ） Si ｂ The second unit layer 15 is made of Al ｃ Cr （１－ｃ－ｄ） Cu ｄN, wherein a, b, c, and d satisfy 0.50≦a≦0.75, 0.005≦b≦0.20, 0.50≦c≦0.85, and 0.005≦d<0.10, the average thickness of the first unit layer 12 is 2 nm or more and 50 nm or less, and the average thickness of the second unit layer 15 is 2 nm or more and 50 nm or less.

[0025] The cutting tool of the first embodiment has a long tool life, especially in high-efficiency machining of nickel-based alloys. The reason for this is presumed to be as follows.

[0026] The first unit layer is Al ａ Ti （１－ａ－ｂ） Si ｂ The first unit layer is made of N. Aluminum (Al) contained in the first unit layer improves the high-temperature hardness of the first unit layer. When the above a is 0.50 or more, the high-temperature hardness and heat resistance of the first unit layer are improved. When the above a is 0.75 or less, the generation of hexagonal crystals is suppressed, and a decrease in the high-temperature hardness of the first unit layer is suppressed.

[0027] Titanium (Ti) contained in the first unit layer improves the high-temperature strength of the first unit layer. The above (1-a-b) is 0.05 or more. This provides an improved high-temperature strength. The above (1-a-b) is 0.495 or less. This ensures sufficient aluminum and silicon contents in the first unit layer, thereby improving the high-temperature hardness, oxidation resistance, heat resistance, and hardness of the first unit layer.

[0028] Silicon (Si) contained in the first unit layer improves the oxidation resistance and heat resistance of the first unit layer. When the above b is 0.005 or more, the oxidation resistance of the first unit layer is improved. In addition, the crystal grains of the first unit layer are refined, and the hardness of the first unit layer is improved. When the above b is 0.20 or less, a decrease in the toughness of the first unit layer is suppressed, and the occurrence of chipping is suppressed.

[0029] The second unit layer is Al ｃ Cr （１－ｃ－ｄ） Cu ｄThe second unit layer is made of N. Aluminum (Al) contained in the second unit layer improves the high-temperature hardness of the second unit layer. When the above c is 0.50 or more, the high-temperature hardness and heat resistance of the second unit layer are improved. When the above c is 0.85 or less, the generation of hexagonal crystals is suppressed, and a decrease in the high-temperature hardness of the second unit layer is suppressed.

[0030] The second unit layer contains chromium (Cr) and aluminum, which improves the heat resistance and high-temperature oxidation resistance of the second unit layer.

[0031] The copper (Cu) contained in the second unit layer has low solubility in chromium, a component of the nickel-based alloy (when the nickel-based alloy is a nickel-chromium alloy). Therefore, the second unit layer containing copper is less likely to adhere to the workpiece made of the nickel-based alloy during cutting. In addition, the second unit layer containing copper has excellent lubricity and oxidation resistance.

[0032] On the other hand, copper does not form nitrides, so it tends to disrupt the crystal lattice of a nitride coating and reduce film hardness. For this reason, the technique of adding copper to an AlCrN film has not been adopted in the past. However, adding silicon to an AlCrN film together with copper to suppress the reduction in hardness due to the addition of copper reduces the amount of aluminum dissolved in the film, which tends to reduce film hardness. After extensive research, the inventors have found that adding silicon to the first unit layer improves the hardness of the first unit layer, adding copper to the second unit layer improves the lubricity, adhesion resistance, and oxidation resistance of the coating, and stacking the first unit layer with the second unit layer improves the hardness, lubricity, adhesion resistance, and oxidation resistance of the entire first layer in a balanced manner.

[0033] The first layer is composed of alternating layers in which first unit layers and second unit layers are alternately stacked. The composition and crystal lattice are discontinuous at the interface between the first unit layer and the second unit layer. Therefore, if a crack occurs on the surface of the coating during cutting, the crack propagation can be suppressed at the interface. This suppresses chipping and breakage, extending the life of the cutting tool.

[0034] As described above, the first unit layer has excellent high-temperature hardness and heat resistance due to aluminum, excellent high-temperature strength due to titanium, and excellent oxidation resistance, heat resistance, and hardness due to silicon. The second unit layer has excellent high-temperature hardness and heat resistance due to aluminum, excellent oxidation resistance and heat resistance due to chromium, and excellent lubricity, adhesion resistance, and oxidation resistance due to copper. The first layer of embodiment 1 has the excellent properties of the first and second unit layers described above, and can have a long tool life even in high-efficiency machining of nickel-based alloys, whose cutting edges tend to become hot during cutting.

[0035] 1 to 4 , a cutting tool 1 according to a first embodiment includes a substrate 2 and a coating 3 disposed on the substrate 2. The coating 3 may cover the entire surface of the substrate 2. It is also within the scope of this embodiment if a portion of the substrate 2 is not covered by the coating 3 or if the coating 3 has a partially different configuration. The coating 3 may cover at least a portion of the substrate 2 that is involved in cutting. In the present disclosure, the portion of the substrate 2 that is involved in cutting refers to a region of the substrate 2 that is surrounded by a cutting edge ridge and an imaginary surface that is, depending on the size and shape of the substrate 2, a distance from the cutting edge ridge toward the substrate 2 along a perpendicular to a tangent to the cutting edge ridge, of, for example, 5 mm, 3 mm, 2 mm, 1 mm, or 0.5 mm.

[0036] The cutting tool of embodiment 1 can be suitably used as cutting tools 1 such as drills, end mills, indexable cutting tips for drills, indexable cutting tips for end mills, indexable cutting tips for milling, indexable cutting tips for turning, metal saws, gear cutting tools, reamers, and taps.

[0037] <Substrate> Any conventionally known material can be used as the substrate.For example, the substrate can be made of cemented carbide (WC-based cemented carbide, cemented carbide containing WC and Co, cemented carbide made by adding carbonitrides of Ti, Ta, Nb, etc. to WC and Co, etc.), cermet (mainly composed of TiC, TiN, TiCN, etc.), high-speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, etc.), cubic boron nitride sintered body, or diamond sintered body.

[0038] The substrate may be, in particular, a WC-based cemented carbide or cermet (particularly a TiCN-based cermet). WC-based cemented carbide or cermet has an excellent balance between hardness and strength, particularly at high temperatures, and therefore, when used as a substrate for a cutting tool, can contribute to extending the life of the cutting tool.

[0039] <Coating> <Configuration of Coating> The coating of embodiment 1 includes a first layer. By covering the substrate, the coating improves various properties of the cutting tool, such as wear resistance and chipping resistance, and has the effect of extending the life of the cutting tool. Note that the coating may include other layers in addition to the first layer. Examples of the other layers include a second layer disposed between the substrate and the first layer, and a third layer disposed on the opposite side of the first layer from the substrate.

[0040] <Coating Thickness> The coating thickness may be 0.4 μm or more and 20 μm or less, 0.5 μm or more and 12 μm or less, 1 μm or more and 10 μm or less, or 2 μm or more and 8 μm or less. When the coating thickness is 0.5 μm or more, the life of the cutting tool can be extended. On the other hand, when the total thickness of the coating is 12 μm or less, chipping of the coating is less likely to occur in the early stages of cutting, and the life of the cutting tool can be extended.

[0041] The thickness of the coating is measured by observing the cross section of the coating using a scanning electron microscope (SEM). The specific measurement method is as follows: The cutting tool is cut in a direction along the normal to the main surface of the coating to prepare a cross section sample. The cross section sample is observed with the SEM. The observation magnification is 5000 to 10000 times, and the measurement field of view is 100 to 500 μm.２ The thickness width of the coating is measured at three points in one field of view, and the average value of the thickness widths at the three points is calculated. This average value corresponds to the thickness of the coating. The thickness of each layer described below is also measured in the same manner unless otherwise specified.

[0042] <Crystalline structure of coating> The crystalline structure of the coating may be cubic. When the crystalline structure of the coating is cubic, the hardness of the coating is improved. The crystalline structure of each layer in the coating (first layer, third layer, second layer, etc.) may also be cubic. The crystalline structure of the coating and each layer in the coating can be analyzed using an X-ray diffraction device known in the art.

[0043] <<Hardness of Coating>> The hardness of the coating may be 30 GPa or more and 50 GPa or less, or 35 GPa or more and 45 GPa or less. According to this, the coating has sufficient hardness. The hardness of the coating is measured by a nanoindenter method (measuring device: ENT-1100a manufactured by Elionix). Specifically, the method is performed in accordance with ISO 14577, with a measuring load of 10 mN (1 gf), and the hardness is measured at 10 points on the surface of the coating, and the average value of the hardness values ​​at the 10 points is calculated. This average value corresponds to the hardness of the coating.

[0044] <First Layer> The first layer of embodiment 1 is composed of alternating layers in which first unit layers and second unit layers are alternately stacked. The fact that the first layer is composed of alternating layers in which first unit layers and second unit layers are alternately stacked can be confirmed by observing a thin section sample including a cross section of the coating with a TEM (transmission electron microscope) and observing the difference in contrast.

[0045] Either the first unit layer or the second unit layer may be disposed closest to the substrate. In FIG. 1 , the first unit layer 12 is disposed directly on the substrate 2, which is the position closest to the substrate 2. In FIG. 2 , the second unit layer 15 is disposed directly on the substrate 2, which is the position closest to the substrate 2. Either the first unit layer 12 or the second unit layer 15 may be disposed on the surface side of the coating 3. In FIG. 1 , the second unit layer 15 is disposed on the surface side of the coating 3. In FIG. 2 , the first unit layer 12 is disposed on the surface side of the coating 3.

[0046] <Thickness of First Layer> The thickness of the first layer may be 0.4 μm or more and 12 μm or less, 0.5 μm or more and 10 μm or less, 1 μm or more and 8 μm or less, or 2 μm or more and 5 μm or less. When the thickness of the first layer is 0.5 μm or more, the wear resistance is excellent and the life of the cutting tool can be extended. On the other hand, when the thickness of the first layer is 10 μm or less, chipping of the coating is unlikely to occur in the early stage of cutting, and the life of the cutting tool can be extended.

[0047] <Composition of First Unit Layer and Second Unit Layer> The first unit layer is Al ａ Ti （１－ａ－ｂ） Si ｂ N, and satisfies 0.50≦a≦0.75 and 0.005≦b≦0.20.

[0048] a may be 0.500 or more and 0.750 or less, 0.550 or more and 0.700 or less, or 0.600 or more and 0.650 or less.

[0049] b may be 0.005 or more and 0.200 or less, 0.010 or more and 0.150 or less, or 0.020 or more and 0.100 or less.

[0050] (1-a-b) is 0.05 or more and 0.495 or less, and may be 0.100 or more and 0.450 or less, or may be 0.200 or more and 0.400 or less.

[0051] The second unit layer is Al ｃ Cr （１－ｃ－ｄ） Cu ｄ N, and satisfies 0.50≦c≦0.85 and 0.005≦d<0.10.

[0052] c is 0.500 or more and 0.850 or less, and may be 0.550 or more and 0.800 or less, or may be 0.600 or more and 0.750 or less.

[0053] d may be 0.005 or more and 0.100 or less, 0.010 or more and 0.090 or less, or 0.020 or more and 0.080 or less.

[0054] (1-cd) is 0.05 or more and 0.495 or less, and may be 0.100 or more and 0.450 or less, or may be 0.200 or more and 0.400 or less.

[0055] b / d may be 1 or more, may exceed 1, may be 1 or more and 30 or less, may be 1.1 or more and 20 or less, may be 1.25 or more and 10 or less, or may be 2 or more and 5 or less. When b / d is 1 or more, the film hardness is improved and the tool life is improved.

[0056] In the present disclosure, "the first unit layer is Al ａ Ti （１－ａ－ｂ） Si ｂ The term "consisting of AlN" means that the first unit layer is made of AlN as long as it does not impair the effect of the present disclosure. ａ Ti （１－ａ－ｂ） Si ｂ This means that the second unit layer may contain inevitable impurities in addition to N. ｃ Cr （１－ｃ－ｄ） Cu ｄ The phrase "consisting of AlN" means that the second unit layer is made of AlN as long as it does not impair the effect of the present disclosure. ｃ Cr （１－ｃ－ｄ） Cu ｄ This means that in addition to N, inevitable impurities may be contained. Examples of inevitable impurities include oxygen and carbon. The total content of inevitable impurities in the first unit layer or the second unit layer may be greater than 0 atomic % and less than 1 atomic %. In the present disclosure, "atomic %" refers to the ratio (%) of the number of atoms to the total number of atoms constituting the layer.

[0057] The contents of a, b, c, d and inevitable impurities in the first unit layer and the second unit layer are measured by elemental analysis of a cross section of the coating using a transmission electron microscope (TEM). The specific measurement method is as follows: A cutting tool is cut in a direction normal to the coating to prepare a thin section sample including a cross section of the coating. An EDS (Energy Dispersive X-ray Spectroscopy) attached to the TEM is used to irradiate the thin section sample with an electron beam, and the energy and number of characteristic X-rays generated are measured to perform elemental analysis of the first unit layer and the second unit layer. Five layers each of the first unit layer and the second unit layer are arbitrarily selected and subjected to elemental analysis. The average composition of the five first unit layers is determined. This average composition corresponds to the composition of the first unit layer. The average composition of the five second unit layers is determined. This average composition corresponds to the composition of the second unit layer. It has been confirmed that as long as measurements are made using the same cutting tool, there is no variation in the measurement results even if the measurement location is selected arbitrarily.

[0058] In the present disclosure, the composition of the first unit layer is Al ａ Ti （１－ａ－ｂ） Si ｂ In N, the total number of Al, Ti and Si atoms A Ｍ１ Number of N atoms A Ｎ１ Ratio A Ｎ１ / A Ｍ１ In the present disclosure, the composition of the second unit layer, Al ｃ Cr （１－ｃ－ｄ） Cu ｄ In N, the total number of Al, Cr and Cu atoms, A Ｍ２ Number of N atoms A Ｎ２ Ratio A Ｎ２ / A Ｍ２ The ratio A is necessarily in the range of 0.8 to 1.2 due to manufacturing reasons. Ｎ１ / A Ｍ１ and ratio A Ｎ２ / A Ｍ２ can be measured by Rutherford backscattering (RBS) method. Ｎ１ / A Ｍ１ and ratio A Ｎ２ / A Ｍ２ It has been confirmed that the effects of the present disclosure are not impaired if the value is within the above range.

[0059] [Correction based on Rule 91 11 / 11 / 2024] <Average Thickness of First Unit Layer and Average Thickness of Second Unit Layer> The average thickness of the first unit layer is 2 nm to 50 nm, and the average thickness of the second unit layer is 2 nm to 50 nm. This can further suppress the propagation of cracks that occur on the surface of the coating. The average thickness of the first unit layer may be 2 nm to 40 nm, 2 nm to 30 nm, or 4 nm to 25 nm. The average thickness of the second unit layer may be 2 nm to 40 nm, 2 nm to 30 nm, or 4 nm to 25 nm.

[0060] The method for measuring the average thickness of the first unit layer and the average thickness of the second unit layer is as follows. Five first unit layers and five second unit layers are randomly selected and their thicknesses are measured using the same method as the method for measuring the thickness of the first layer described above. The average thickness of the five first unit layers is determined. This average thickness corresponds to the average thickness of the first unit layers. The average thickness of the five second unit layers is determined. This average thickness corresponds to the average thickness of the second unit layers.

[0061] 5 , in a first unit layer 12 and a second unit layer 15 adjacent to the first unit layer 12, the ratio λ1 / λ2 of the thickness λ1 of the first unit layer 12 to the thickness λ2 of the second unit layer 15 may be 1 or more, greater than 1, 1 or more and 5 or less, greater than 1 and 5 or less, 1.1 or more and 4 or less, 1.2 or more and 3.8 or less, or 1.5 or more and 2.5 or less. When the ratio λ1 / λ2 exceeds 1, the proportion of the first unit layer in the coating increases relatively, and the amount of silicon in the coating increases, thereby improving the oxidation resistance and hardness of the cutting tool as a whole.

[0062] The method for measuring λ1 / λ2 is as follows: Five combinations of adjacent first unit layers and second unit layers are arbitrarily selected so that the unit layers do not overlap. For each combination, the thickness λ1 of the first unit layer and the thickness λ2 of the second unit layer are measured using a method similar to the method for measuring the thickness of the first layer described above, and a first λ1 / λ2 is calculated. The average of the five first λ1 / λ2 values ​​is calculated. In the present disclosure, this average corresponds to λ1 / λ2.

[0063] For the sake of explanation, in Figure 5, the thicknesses of all three first unit layers 12 are shown as λ1 and the thicknesses of all three second unit layers 15 are shown as λ2. However, as long as the above-mentioned λ1 / λ2 relationship is satisfied between adjacent first unit layers and second unit layers, the thickness λ1 of all first unit layers 12 does not need to be the same, and the thickness λ2 of all second unit layers 15 does not need to be the same.

[0064] In the first layer, the total number of stacked first unit layers and second unit layers may be 10 or more and 3000 or less. By stacking the first unit layers and the second unit layers, the effect of improving the hardness and lubricity of the coating in a well-balanced manner can be sufficiently obtained. In the first layer, the total number of stacked first unit layers and second unit layers may be 100 or more and 2500 or less, or 200 or more and 2000 or less. For example, if the first layer contains 500 first unit layers and 500 second unit layers, the total number of stacked first unit layers and second unit layers is 1000.

[0065] In the first layer, the number of first unit layers and second unit layers can be determined by observing a thin section sample of the cross section of the coating using a TEM (transmission electron microscope) at a magnification of 20,000 to 5,000,000 times.

[0066] 3 and 4, the coating 3 may further include a second layer 16 provided between the substrate 2 and the first layer 13. The second layer 16 may be provided directly on the substrate.

[0067] The second layer may be composed of at least one element selected from Group 1 consisting of Group 4, Group 5, and Group 6 elements, aluminum (Al), and silicon (Si), or a first compound consisting of at least one element selected from Group 1 and at least one element selected from Group 2 consisting of carbon (C), nitrogen (N), oxygen (O), and boron (B). Examples of Group 4 elements include titanium (Ti), zirconium (Zr), and hafnium (Hf). Examples of Group 5 elements include vanadium (V), niobium (Nb), and tantalum (Ta). Examples of Group 6 elements include chromium (Cr), molybdenum (Mo), and tungsten (W). The second layer can improve adhesion between the substrate and the coating, thereby improving tool life. The second layer may contain unavoidable impurities in addition to at least one element selected from Group 1 or the first compound, as long as the effects of the present disclosure are not impaired.

[0068] The second layer may be made of a first compound consisting of at least one element selected from Group 1A consisting of Cr, Al, Ti, and Si, or at least one element selected from Group 1A and at least one element selected from Group 2 consisting of carbon, nitrogen, oxygen, and boron.

[0069] Examples of the first compound include TiWCN, TiN, TiAlN, TiAlON, and Al ２ O ３ , TiAlSiN, TiCrSiN, TiAlCrSiN, AlCrN, AlCrO, AlCrON, AlCrSiN, AlCrBN, TiZrN, TiAlMoN, TiAlNbN, TiSiN, AlCrTaN, AlVN, AlTiVN, TiB ２ , TiCrHfN, CrSiWN, TiAlCN, TiSiCN, AlZrON, AlCrCN, AlHfN, CrSiBON, TiAlWN, AlCrMoCN, TiCN, TiCON, ZrN and ZrCN.

[0070] The thickness of the second layer is not particularly limited as long as it does not impair the effects of this embodiment, but can be, for example, 0.1 μm or more and 2 μm or less.

[0071] 1 to 4, the coating 3 may further include a third layer 14 provided on the side of the first layer 13 opposite the substrate 2. The third layer 14 may be provided directly on the first layer 13. Another layer may be provided between the first layer 13 and the third layer 14. The third layer 14 may be the outermost layer.

[0072] The third layer may be composed of at least one element selected from Group 1 consisting of Group 4, Group 5, and Group 6 elements of the periodic table, aluminum (Al), and silicon (Si), or a second compound consisting of at least one element selected from Group 1 and at least one element selected from Group 2 consisting of carbon (C), nitrogen (N), oxygen (O), and boron (B). The third layer can reduce the friction coefficient of the coating and extend the life of the cutting tool. The third layer may contain impurities in addition to at least one element selected from Group 1 or the second compound, as long as the effects of the present disclosure are not impaired.

[0073] The third layer may be made of at least one element selected from Group 1A consisting of Cr, Al, Ti, and Si, or a second compound made of at least one element selected from Group 1A and at least one element selected from Group 2 consisting of carbon, nitrogen, oxygen, and boron.

[0074] Examples of the second compound include AlTiBN, TiAlN, TiAlON, and Al ２ O ３ , TiAlSiN, TiCrSiN, TiAlCrSiN, AlCrN, AlCrO, AlCrON, AlCrSiN, AlCrBN, TiZrN, TiAlMoN, TiAlNbN, TiSiN, AlCrTaN, AlVN, AlTiVN, TiB ２ , TiCrHfN, CrSiWN, TiAlCN, TiSiCN, AlZrON, AlCrCN, AlHfN, CrSiBON, TiAlWN, AlCrMoCN, TiCN, TiCON, ZrN and ZrCN.

[0075] The thickness of the third layer may be 0.1 μm or more and 2 μm or less. When the thickness of the third layer is 0.1 μm or more, the lubricity-imparting effect of the third layer is easily obtained. There is no particular upper limit to the thickness of the third layer, but when it exceeds 2 μm, the above-mentioned lubricity-imparting effect tends not to be further improved. Therefore, in consideration of cost, the thickness of the third layer may be 2 μm or less.

[0076] <Intermediate Layer> The coating may include an intermediate layer provided between the third layer and the first layer, or between the first layer and the second layer. Examples of intermediate layers include TiAlCeN, AlTiN, AlTiBN, AlTiSiN, AlTiYN, and AlTiLaN. The thickness of the intermediate layer may be 0.1 μm or more and 2 μm or less, 0.3 μm or more and 1.5 μm or less, or 0.4 μm or more and 1.0 μm or less.

[0077] [Embodiment 2: Method for Manufacturing Cutting Tool] In embodiment 2, a method for manufacturing the cutting tool of embodiment 1 will be described. The manufacturing method includes a first step of preparing a substrate and a second step of forming a coating on the substrate. The second step includes a step of forming a first layer. Details of each step will be described below.

[0078] <First Step> In the first step, a substrate is prepared. The substrate may be the substrate described in embodiment 1. Any substrate that is conventionally known may be prepared.

[0079] <Second Step> In the second step, a coating is formed on the substrate. The second step includes a step of forming a first layer.

[0080] In the step of forming the first layer, the first unit layer and the second unit layer are alternately laminated using a physical vapor deposition (PVD) method to form the first layer. To improve the abrasion resistance of a coating including the first layer, it is highly effective to form a layer made of a highly crystalline compound. The inventors have investigated various methods for forming the first layer and found that physical vapor deposition is highly effective.

[0081] The PVD method may be at least one selected from the group consisting of cathodic arc ion plating, balanced magnetron sputtering, unbalanced magnetron sputtering, and HiPIMS. In particular, cathodic arc ion plating, which has a high ionization rate of the raw material elements, may be used. When cathodic arc ion plating is used, it is possible to perform ion bombardment of metal on the surface of the substrate before forming the first layer, thereby significantly improving adhesion between the substrate and the coating including the first layer.

[0082] The cathodic arc ion plating method can be carried out, for example, by placing a substrate in an apparatus and a target as a cathode, and then applying a high voltage to the target to generate an arc discharge, thereby ionizing and evaporating the atoms that make up the target, and depositing the material on the substrate.

[0083] <Other Steps> In addition to the step of forming the first layer, the second step may include a surface treatment step such as surface grinding or shot blasting. The second step may also include the step of forming other layers such as a second layer, a third layer, and an intermediate layer. The other layers may be formed by a conventionally known chemical vapor deposition method or physical vapor deposition method. From the viewpoint that the other layers can be formed continuously with the first layer in a single physical vapor deposition apparatus, the other layers may be formed by physical vapor deposition.

[0084] The present embodiment will be described in more detail with reference to examples, although the present embodiment is not limited to these examples.

[0085] <<Fabrication of Cutting Tool>> FIG. 6 is a schematic cross-sectional view of the cathodic arc ion plating apparatus used in this example, and FIG. 7 is a schematic top view of the apparatus of FIG.

[0086] 6 and 7, a cathode 106 for a first unit layer, which is an alloy target serving as a metal raw material for the coating, a cathode 107 for a second unit layer, and a rotary substrate holder 104 for placing a substrate are installed in a chamber 101. The compositions of the cathodes 106 and 107 are adjusted so as to obtain the compositions shown in Tables 1 and 2 below.

[0087] In the sample device where the second or third layer is formed, a cathode for the second layer (not shown) or a cathode for the third layer (not shown) is also installed in the chamber 101. The compositions of the cathode for the second layer and the cathode for the third layer are adjusted so as to obtain the compositions shown in Tables 3 and 4 below.

[0088] An arc power supply 108 is attached to cathode 106, and an arc power supply 109 is attached to cathode 107. A bias power supply 110 is attached to substrate holder 104. A gas inlet for introducing gas 105 and a gas outlet 103 for adjusting the pressure inside chamber 101 are provided inside chamber 101, and the gas inside chamber 101 can be sucked out from gas outlet 103 by a vacuum pump.

[0089] A four-blade ball end mill with a ball radius of 5 mm and made of cemented carbide of grade JIS standard K20 was attached to the substrate holder 104 as the substrate.

[0090] Next, the pressure inside the chamber 101 was reduced by a vacuum pump, and the substrate was heated to 500° C. by a heater installed inside the apparatus while being rotated, until the pressure inside the chamber 101 reached 1.0×10 －４ The chamber was evacuated to a vacuum of 2.0 Pa. Next, argon gas was introduced through the gas inlet to maintain the pressure inside the chamber 101 at 2.0 Pa, and the voltage of the bias power supply 110 was gradually increased to -1000 V, and the surface of the substrate was cleaned for 15 minutes. Thereafter, the argon gas was exhausted from the chamber 101 to clean the substrate (argon bombardment treatment). In this manner, the substrate for each sample cutting tool was prepared.

[0091] Next, while the substrate was rotated at the center, nitrogen was introduced as a reactive gas, and an arc current of 150 A was supplied to each of cathodes 106 and 107 while maintaining the substrate temperature at 550°C, the reactive gas pressure at 2.0 Pa, and the voltage of bias power supply 110 at a constant value in the range of -50 V to -300 V. Metal ions were generated from cathodes 106 and 107, and a first layer consisting of a first unit layer and a second unit layer having the compositions shown in Tables 1 and 2 below was formed on the substrate.

[0092] When a second layer was formed, the second layer was formed on the substrate, and then the first layer was formed on the second layer. The second layer was formed using the following procedure. The substrate temperature was set to 550°C, and the gas pressure in the apparatus was set to 3.0 Pa. A mixed gas of nitrogen gas and argon gas was introduced as the reactive gas. Then, an arc current of 150 A was supplied to the cathode electrode. The second layer was formed by generating metal ions and the like from the arc evaporation source by supplying the arc current.

[0093] When a third layer was formed, it was formed on the first layer. The third layer was formed using the following procedure. The substrate temperature was set to 550°C, and the gas pressure inside the apparatus was set to 3.0 Pa. A mixed gas of nitrogen gas and argon gas, or oxygen gas, was introduced as the reactive gas. Then, an arc current of 150 A was supplied to the cathode electrode. The third layer was formed by generating metal ions and the like from the arc evaporation source by supplying the arc current.

[0094] In this manner, cutting tools for each sample were produced.

[0095]

[0096]

[0097]

[0098]

[0099] <Evaluation> <Measurement of Composition of First Unit Layer and Second Unit Layer> For each sample cutting tool, the composition of the first unit layer and the second unit layer was measured by the method described in embodiment 1. First unit layer Al ａ Ti （１－ａ－ｂ） Siｂ N, and the second unit layer Al ｃ Cr （１－ｃ－ｄ） Cu ｄ The values ​​of a, b, c and d in N are shown in Tables 1 and 2. Furthermore, b / d is shown in Tables 1 and 2.

[0100] <Measurement of Composition of Second Layer and Composition of Third Layer> For each sample cutting tool, the composition of the second layer and the third layer was measured by the method described in Embodiment 1. The results are shown in Tables 3 and 4. "-" means that the corresponding layer was not present.

[0101] <Measurement of Average Thickness of First Unit Layer, Average Thickness of Second Unit Layer, Thickness of First Layer, Thickness of Second Layer, and Thickness of Third Layer> For each sample cutting tool, the average thickness of the first unit layer, the average thickness of the second unit layer, the thickness of the first layer, the thickness of the second layer, and the thickness of the third layer were measured by the method described in Embodiment 1. The results are shown in Tables 1 to 4.

[0102] <Measurement of λ1 / λ2> For each sample cutting tool, the ratio λ1 / λ2 of the thickness λ1 of the first unit layer 12 to the thickness λ2 of the second unit layer 15 in the adjacent first unit layer and second unit layer was determined by the method described in embodiment 1. The obtained results are shown in Tables 1 and 2.

[0103] <Measurement of Number of Laminations> For each sample cutting tool, the total number of laminations of first unit layers and second unit layers was determined by the method described in embodiment 1. The results are shown in Tables 1 and 2. For example, a lamination number of 100 indicates that 50 first unit layers and 50 second unit layers are laminated. A lamination number of 667 indicates that 334 first unit layers and 333 second unit layers are laminated.

[0104] <Crystalline Structure of Coating> The crystalline structure of the coating of each cutting tool sample was analyzed by the method described in embodiment 1. In samples 1 to 27, the crystalline structure was cubic.

[0105] <Coating Hardness> The coating hardness of each sample cutting tool was analyzed by the method described in embodiment 1. In samples 1 to 27, the coating hardness was 30 GPa or more and 50 GPa or less.

[0106] <Cutting test> Using each sample cutting tool, a side machining test was performed under the following conditions, and the cutting distance until the wear width or chipping width of the cutting edge reached 100 μm was measured. The results are shown in Table 2. A long cutting distance indicates a long tool life. <Cutting conditions> Workpiece material: Inconel 718 Cutting speed Vc: 60 m / min Feed rate fz: 0.05 mm / t Depth of cut: ap = 3.0 mm, ae = 1.0 mm External coolant supplied The above cutting conditions correspond to high-efficiency machining of nickel-based alloys.

[0107] The cutting tools of Samples 1 to 27 correspond to Examples, and the cutting tools of Samples 1-1 to 1-11 correspond to Comparative Examples. It was confirmed that the cutting tools of Samples 1 to 27 have a longer tool life in high-efficiency machining of nickel-based alloys than the cutting tools of Samples 1-1 to 1-11.

[0108] Although the embodiments and examples of the present disclosure have been described above, it is intended from the beginning that the configurations of the above-described embodiments and examples may be appropriately combined or modified in various ways. The embodiments and examples disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims, not by the above-described embodiments and examples, and is intended to include meanings equivalent to the claims and all modifications within the scope of the claims.

[0109] REFERENCE SIGNS LIST 1 Cutting tool, 2 Substrate, 3 Coating, 12 First unit layer, 13 First layer, 14 Third layer, 15 Second unit layer, 16 Second layer, 101 Chamber, 103 Gas outlet, 104 Substrate holder, 105 Gas, 106, 107 Cathode, 108, 109 Arc power supply, 110 Bias power supply.

Claims

1. [Amendment based on Rule 91 11.11.2024] A cutting tool comprising a substrate and a coating disposed on the substrate, wherein the coating includes a first layer, the first layer being composed of alternating layers in which first unit layers and second unit layers are alternately stacked, and the first unit layer is made of Al ａ Ti （１－ａ－ｂ） Si ｂ N, and the second unit layer is made of Al ｃ Cr （１－ｃ－ｄ） Cu ｄ N, wherein the a, the b, the c, and the d satisfy 0.50≦a≦0.75, 0.005≦b≦0.20, 0.50≦c≦0.85, and 0.005≦d<0.10, the first unit layer has an average thickness of 2 nm or more and 50 nm or less, and the second unit layer has an average thickness of 2 nm or more and 50 nm or less.

2. The cutting tool according to claim 1, wherein b and d satisfy the relationship b / d≧1.

3. A cutting tool according to claim 1 or claim 2, wherein the ratio λ1 / λ2 of the thickness λ1 of the first unit layer to the thickness λ2 of the second unit layer in the first unit layer and the second unit layer adjacent to the first unit layer is greater than 1.

0.

4. A cutting tool according to any one of claims 1 to 3, wherein the thickness of the first layer is 0.5 μm or more and 10 μm or less.

5. A cutting tool according to any one of claims 1 to 4, wherein the coating further includes a second layer provided between the substrate and the first layer, and the second layer comprises at least one element selected from a first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum, and silicon of the periodic table, or a first compound comprising at least one element selected from the first group and at least one element selected from a second group consisting of carbon, nitrogen, oxygen, and boron.

6. A cutting tool according to any one of claims 1 to 5, wherein the coating further includes a third layer disposed on the first layer opposite the substrate, the third layer consisting of at least one element selected from a first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum, and silicon of the periodic table, or a second compound consisting of at least one element selected from the first group and at least one element selected from a second group consisting of carbon, nitrogen, oxygen, and boron.

7. A cutting tool according to any one of claims 1 to 6, wherein the coating has a thickness of 0.5 μm or more and 12 μm or less.

8. A cutting tool according to any one of claims 1 to 7, wherein the substrate is made of cemented carbide, cermet, cubic boron nitride sintered body, diamond sintered body, high-speed steel, or ceramics.

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