Cutting tool

Abstract

A cutting tool comprising a substrate and a coating disposed on the substrate, wherein the coating includes a first layer, and the first layer is composed of an alternating layer in which a first unit layer and a second unit layer are alternately laminated, and the first unit layer is Al a Ti (1-a-b) Si b N, and the second unit layer is Al c Cr (1-c-d) Ag d N, where 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, and the average thickness of the first unit layer is 2 nm or more and 50 n m or less, and the average thickness of the second unit layer is 2 nm or more and 50 n m or less.

Description

Technical Field

[0001] The present disclosure relates to a cutting tool.

Background Art

[0002] Conventionally, a cutting tool including a base material and a coating disposed on the base material has been used for cutting (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The cutting tool of the present disclosure is a cutting tool including a base material and a coating disposed on the base material, the coating includes a first layer, the first layer is composed of an alternating layer in which a first unit layer and a second unit layer are alternately laminated, the first unit layer is Al a Ti (1-a-b) Si b and N, the second unit layer is Al c Cr (1-c-d) Ag d and N, where a, b, c, and d are 0.50 ≦ a ≦ 0.75, 0.005 ≦ b ≦ 0.20, 0.50 ≦ c ≦ 0.85, and 0.005 ≦ d < 0.10 are satisfied, 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.

Brief Description of the Drawings

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Mode for Carrying Out the Invention

[0006] [Problems to be Solved by the Present Disclosure] In recent years, the materials to be cut have diversified, and in particular, in the fields of aircraft and medicine, the cutting of nickel-based alloys called difficult-to-cut materials has increased. When continuously machining nickel-based alloys using a cutting tool, the cutting edge temperature becomes high, and the life of the cutting tool is shortened. Therefore, in particular, there is a demand for a cutting tool that can have a long tool life even in the high-efficiency machining of nickel-based alloys.

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

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

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. (1) The 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, the first layer is composed of an alternating layer in which a first unit layer and a second unit layer are alternately laminated, the first unit layer is composed of Al a Ti (1-a-b) Si b N, the second unit layer is composed of Al c Cr (1-c-d) Ag d N, 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 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, in particular, it is possible to provide a cutting tool that can have a long tool life even in high-efficiency machining of nickel-based alloys.

[0011] (2) In the above (1), b and d may satisfy the relationship of b / d ≧ 1. According to this, the tool life is further improved.

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

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

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

[0015] According to this, the tool life is further improved.

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

[0017] According to this, the tool life is further improved.

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

[0019] (8) In any one of (1) to (7) above, the base material may be made of cemented carbide, cermet, cubic boron nitride sintered body, diamond sintered body, high-speed steel, or ceramics. According to this, the tool life is further improved.

[0020] [Details of Embodiments of the Present Disclosure] A specific example of the cutting tool of 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. Also, dimensional relationships such as length, width, thickness, depth, etc. 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 the range (i.e., A or more and B or less). When there is no unit description for A and only the unit is described for B, the unit of A and the unit of B are the same.

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

[0023] In the present disclosure, when one or more numerical values are described as the lower limit and the upper limit of a numerical range, respectively, any combination of any one of the numerical values described as the lower limit and any one of the numerical values described as the upper limit is also disclosed.

[0024] [Embodiment 1: Cutting Tool] As shown in FIGS. 1 to 4, a cutting tool according to an embodiment of the present disclosure (hereinafter, also referred to as "Embodiment 1") is a cutting tool 1 including a base material 2 and a coating 3 disposed on the base material 2, the coating 3 includes a first layer 13, the first layer 13 is composed of an alternating layer in which a first unit layer 12 and a second unit layer 15 are alternately laminated, the first unit layer 12 is composed of Al a Ti (1-a-b) Si b N, the second unit layer 15 is composed of Al c Cr (1-c-d) Ag d N, a, b, c and d are 0.50 ≦ a ≦ 0.75, 0.005 ≦ b ≦ 0.20, 0.50 ≦ c ≦ 0.85, and 0.005 ≦ d < 0.10 are satisfied, The average thickness of the first unit layer 12 is 2 nm or more and 50 nm or less, The average thickness of the second unit layer 15 is 2 nm or more and 50 nm or less, which is a cutting tool.

[0025] The cutting tool of Embodiment 1 can have a long tool life, especially in the high-efficiency machining of nickel-based alloys. The reason is presumed as follows.

[0026] The first unit layer is composed of Al a Ti (1-a-b) Si b 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 formation of hexagonal crystals is suppressed, and the 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. Thereby, the effect of improving the high-temperature strength can be obtained. The above (1 - a - b) is 0.495 or less. Thereby, since the contents of aluminum and silicon in the first unit layer can be sufficiently ensured, the high-temperature hardness, oxidation resistance, heat resistance, and hardness of the first unit layer are improved.

[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. Also, 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, the decrease in the toughness of the first unit layer is suppressed, and the occurrence of chipping is suppressed.

[0029] The second unit layer is composed of Al c Cr (1-c-d) Ag dIt consists of N. Aluminum (Al) contained in the second unit layer improves the high-temperature hardness of the second unit layer. When c is 0.50 or more, the high-temperature hardness and heat resistance of the second unit layer are improved. When c is 0.85 or less, the formation of hexagonal crystals is suppressed, and the decrease in the high-temperature hardness of the second unit layer is suppressed.

[0030] When the second unit layer contains chromium (Cr) and aluminum, the heat resistance and high-temperature oxidation resistance of the second unit layer are improved.

[0031] Silver (Ag) contained in the second unit layer forms an oxide film on the surface side of the coating of the second unit layer, improving the lubricity of the coating. Also, silver has low solubility with respect to nickel and chromium which are components of the nickel-based alloy (when the nickel-based alloy is a nickel-chromium alloy). Therefore, the second unit layer containing silver is less likely to adhere to the work material made of the nickel-based alloy during cutting.

[0032] On the other hand, since silver does not form nitrides, it tends to disrupt the crystal lattice of the nitride film and lower the film hardness. Therefore, conventionally, the technique of adding silver to the AlCrN film has not been adopted. In addition, in order to suppress the hardness reduction due to the addition of silver, when silicon is added to the AlCrN film together with silver, the solid solution amount of aluminum decreases, and the film hardness tends to decrease. As a result of intensive studies by the present inventors, by adding silicon to the first unit layer, the hardness of the first unit layer is improved, and by adding silver to the second unit layer, the lubricity, anti-adhesion property, and oxidation resistance of the coating are improved. By laminating the first unit layer and the second unit layer, it has been found that the hardness and lubricity can be improved in a well-balanced manner throughout the first layer.

[0033] The first layer consists of an alternating layer in which the first unit layer and the second unit layer are alternately laminated. At the interface between the first unit layer and the second unit layer, the composition and crystal lattice are discontinuous. Therefore, when cracks occur from the surface of the coating during cutting, the progress of the cracks can be suppressed at this interface. Accordingly, chipping and defects are suppressed, and the life of the cutting tool becomes longer.

[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, seizure resistance, and oxidation resistance due to silver. The first layer of Embodiment 1 has the excellent characteristics of the above-mentioned first unit layer and second unit layer, and can have a long tool life even in the high-efficiency machining of nickel-based alloys where the cutting edge tends to become hot during cutting.

[0035] <Cutting tool> As shown in FIGS. 1 to 4, the cutting tool 1 according to Embodiment 1 includes a base material 2 and a coating 3 disposed on the base material 2. The coating 3 may cover the entire surface of the base material 2. Further, even if a part of the base material 2 is not covered by the coating 3 or the configuration of the coating 3 is partially different, it does not deviate from the scope of the present embodiment. The coating 3 may cover at least the portion of the base material 2 involved in cutting. In the present disclosure, the portion of the base material 2 involved in cutting means, depending on the size and shape of the base material 2, in the base material 2, the cutting edge ridge line and, from the cutting edge ridge line toward the base material 2 side, a virtual surface surrounded by a distance along the perpendicular to the tangent line of the cutting edge ridge line being, for example, any one of 5 mm, 3 mm, 2 mm, 1 mm, and 0.5 mm.

[0036] The cutting tool of Embodiment 1 can be suitably used as a cutting tool 1 such as a drill, an end mill, a cutting tip for drill with replaceable cutting edge, a cutting tip for end mill with replaceable cutting edge, a cutting tip for milling with replaceable cutting edge, a cutting tip for turning with replaceable cutting edge, a metal saw, a toothing tool, a reamer, a tap, etc.

[0037] <Base material> As the base material, any conventionally known material can be used. For example, the base material may be a cemented carbide (WC-based cemented carbide, cemented carbide containing WC and Co, cemented carbide obtained by adding carbonitrides such as Ti, Ta, Nb to WC and Co, etc.), cermet (one 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 base material may particularly be a WC-based cemented carbide or a cermet (particularly a TiCN-based cermet). Since a WC-based cemented carbide or a cermet is particularly excellent in the balance between hardness and strength at high temperatures, it can contribute to extending the life of a cutting tool when used as the base material of a cutting tool.

[0039] <Coating> ≪Configuration of Coating≫ The coating of Embodiment 1 includes a first layer. By coating the base material, the coating has the effect of improving various properties such as the wear resistance and chipping resistance of the cutting tool and bringing about an extended life of the cutting tool. Note that the coating may include other layers in addition to the first layer. Examples of other layers include a second layer disposed between the base material and the first layer, and a third layer provided on the side opposite to the base material of the first layer.

[0040] ≪Thickness of Coating≫ The thickness of the coating may be 0.4 μm or more and 20 μm or less, may be 0.5 μm or more and 12 μm or less, may be 1 μm or more and 10 μm or less, or may be 2 μm or more and 8 μm or less. When the thickness of the coating is 0.5 μm or more, the life of the cutting tool can be made longer. On the other hand, when the total thickness of the coating is 12 μm or less, chipping in the coating hardly occurs at the initial stage of cutting, and the life of the cutting tool can be made longer.

[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. Cut the cutting tool in a direction along the normal of the main surface of the coating to prepare a cross-section sample. Observe the cross-section sample with SEM. The observation magnification is set to 5000 - 10000 times, and the measurement field of view is 100 - 500 μm. 2 In one field of view, measure the thickness widths at three locations of the coating and calculate the average value of the three thickness widths. This average value corresponds to the thickness of the coating. For the thickness of each layer described below, unless otherwise specified, it is measured in the same manner.

[0042] ≪Crystal Structure of the Coating≫ The crystal structure of the coating may be a cubic crystal type. When the crystal structure of the coating is a cubic crystal type, the hardness of the coating is improved. The crystal structure of each layer (the first layer, the third layer, the second layer, etc.) in the coating may also be a cubic crystal type. The crystal structure of the coating and each layer in the coating can be analyzed by an X-ray diffractometer known in the art.

[0043] ≪Hardness of the Coating≫ The hardness of the coating may be 30 GPa or more and 50 GPa or less, or may be 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 the nanoindentation method (measurement device: ENT-1100a manufactured by Elionix). Specifically, it is performed by a method compliant with ISO14577. The measurement load is 10 mN (1 gf), and the hardness at 10 locations on the surface of the coating is measured, and the average value of the hardness at 10 locations is calculated. This average value corresponds to the hardness of the coating.

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

[0045] Either the first unit layer or the second unit layer may be disposed at the position closest to the substrate side. In FIG. 1, the first unit layer 12 is disposed immediately above the substrate 2, which is the position closest to the substrate 2. In FIG. 2, the second unit layer 15 is disposed immediately above 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 the 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 in the coating is less likely to occur at the initial stage of cutting, and the life of the cutting tool can be extended.

[0047] <Composition of the first unit layer and the second unit layer> The first unit layer is composed of 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, may be 0.100 or more and 0.450 or less, or 0.200 or more and 0.400 or less.

[0051] The second unit layer is composed of Alc Cr (1-c-d) Ag d It consists of 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, 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, may be 0.010 or more and 0.090 or less, or may be 0.020 or more and 0.080 or less.

[0054] (1 - c - d) is 0.05 or more and 0.495 or less, 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 be more than 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 consists of Al a Ti (1-a-b) Si b N" means that, as long as the effects of the present disclosure are not impaired, the first unit layer may contain inevitable impurities in addition to Al a Ti (1-a-b) Si b N. In the present disclosure, "the second unit layer consists of Al c Cr (1-c-d) Ag d N" means that, as long as the effects of the present disclosure are not impaired, the second unit layer may contain inevitable impurities in addition to Al c Cr (1-c-d) Ag dIn addition to N, it means that it can contain inevitable impurities. Examples of inevitable impurities include oxygen and carbon. The total content rate 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 %" means the ratio (%) of the number of atoms to the total number of atoms constituting the layer.

[0057] a, b, c, d, the content rate of inevitable impurities in the first unit layer, and the content rate of inevitable impurities in the second unit layer are measured by performing elemental analysis on the cross-section of the film using a transmission electron microscope (TEM). The specific measurement method is as follows. Cut the cutting tool in the direction along the normal of the film to prepare a thin sample including the cross-section of the film. e ) is used to irradiate the thin sample with an electron beam, measure the energy and the number of occurrences of characteristic X-rays generated at that time, and perform elemental analysis on the first unit layer and the second unit layer. Arbitrarily select five layers each of the first unit layer and the second unit layer and perform elemental analysis. Obtain the average composition of the five layers of the first unit layer. The average composition corresponds to the composition of the first unit layer. Obtain the average composition of the five layers of the second unit layer. The average composition corresponds to the composition of the second unit layer. As long as the measurement is performed with the same cutting tool, it has been confirmed that there is no variation in the measurement results even if the measurement location is arbitrarily selected.

[0058] In the present disclosure, in the composition Al a Ti (1-a-b) Si b N, the ratio A M1 of the number of atoms of N to the total number of atoms A N1 of Al, Ti, and Si N1 / A M1 is inevitably in the range of 0.8 to 1.2 in terms of production. In the present disclosure, in the composition Al c Cr (1-c-d) Ag d N, the ratio A M2 of the number of atoms of N to the total number of atoms A N2 of Al, Cr, and Ag N2 / AM2 is inevitably in the range of 0.8 to 1.2 during manufacturing. Ratio A N1 / A M1 and ratio A N2 / A M2 can be measured by the Rutherford backscattering (RBS) method. The above ratio A N1 / A M1 and ratio A N2 / A M2 If they are within the above ranges, it has been confirmed that the effects of the present disclosure are not impaired.

[0059] <Average Thickness of the First Unit Layer and Average Thickness of the Second Unit Layer> 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. According to this, the progress of cracks generated on the surface of the film can be further suppressed. The average thickness of the first unit layer may be 2 nm or more and 40 nm or less, 2 nm or more and 30 nm or less, or 4 nm or more and 25 nm or less. The average thickness of the second unit layer may be 2 nm or more and 40 nm or less, 2 nm or more and 30 nm or less, or 4 nm or more and 25 nm or less.

[0060] The measuring methods for the average thickness of the first unit layer and the average thickness of the second unit layer are as follows. In the same method as the measuring method for the thickness of the above first layer, five layers each of the first unit layer and the second unit layer are arbitrarily selected, and the thickness is measured. The average thickness of the five layers of the first unit layer is obtained. This average thickness corresponds to the average thickness of the first unit layer. The average thickness of the five layers of the second unit layer is obtained. This average thickness corresponds to the average thickness of the second unit layer.

[0061] As shown in FIG. 5, in the first unit layer 12 and the 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, may be more than 1, may be 1 or more and 5 or less, may be more than 1 and 5 or less, may be 1.1 or more and 4 or less, may be 1.2 or more and 3.8 or less, or may be 1.5 or more and 2.5 or less. When the ratio λ1 / λ2 is more than 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 entire cutting tool.

[0062] The measuring method of λ1 / λ2 is as follows. Five combinations of the first unit layer and the second unit layer adjacent to each other are arbitrarily selected so that the unit layers do not overlap. In each combination, the thickness λ1 of the first unit layer and the thickness λ2 of the second unit layer are measured by the same method as the measuring method of the thickness of the first layer described above, and the first λ1 / λ2 is calculated. The average of the five first λ1 / λ2 is calculated. In the present disclosure, the average corresponds to λ1 / λ2.

[0063] In FIG. 5, for the sake of explanation, 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 relationship of λ1 / λ2 is satisfied between the first unit layer and the second unit layer adjacent to each other, the thicknesses λ1 of all the first unit layers 12 do not have to be the same, and the thicknesses λ2 of all the second unit layers 15 do not have 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. According to this, by stacking the first unit layer and the second unit layer, 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 may be 200 or more and 2000 or less. For example, when there are 500 first unit layers and 500 second unit layers in the first layer, the total number of stacked first unit layers and second unit layers is 1000.

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

[0066] <Second layer> As shown in FIGS. 3 and 4, the film 3 may further include a second layer 16 provided between the base material 2 and the first layer 13. The second layer 16 may be provided immediately above the base material.

[0067] The second layer is composed of at least one element selected from the first group consisting of group 4 elements, group 5 elements, group 6 elements, aluminum (Al), and silicon (Si) of the periodic table, or a first compound composed of at least one element selected from the first group and at least one element selected from the second group consisting of carbon (C), nitrogen (N), oxygen (O), and boron (B). Examples of group 4 elements of the periodic table include titanium (Ti), zirconium (Zr), hafnium (Hf), etc. Examples of group 5 elements of the periodic table include vanadium (V), niobium (Nb), tantalum (Ta), etc. Examples of group 6 elements of the periodic table include chromium (Cr), molybdenum (Mo), tungsten (W), etc. The second layer can enhance the adhesion between the base material and the film, and improve the tool life. As long as the effects of the present disclosure are not impaired, the second layer can contain inevitable impurities in addition to at least one element selected from the first group or the first compound.

[0068] The second layer can be composed of at least one element selected from the first A group consisting of Cr, Al, Ti, and Si, or a first compound composed of at least one element selected from the first A group and at least one element selected from the second group consisting of carbon, nitrogen, oxygen, and boron.

[0069] Examples of the first compound include TiWCN, TiN, TiAlN, TiAlON, Al2O3, TiAlSiN, TiCrSiN, TiAlCrSiN, AlCrN, AlCrO, AlCrON, AlCrSiN, AlCrBN, TiZrN, TiAlMoN, TiAlNbN, TiSiN, AlCrTaN, AlVN, AlTiVN, TiB2, 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 the effects of the present embodiment are not impaired, and can be, for example, 0.1 μm or more and 2 μm or less.

[0071] <Third layer> As shown in FIGS. 1 to 4, the coating 3 may further include a third layer 14 provided on the side opposite to the base material 2 of the first layer 13. The third layer 14 may be provided directly above 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 is made of at least one element selected from Group 1 consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum (Al), and silicon (Si) in the periodic table, or a second compound made 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 service life of the cutting tool. As long as the effects of the present disclosure are not impaired, the third layer can contain impurities in addition to at least one element selected from Group 1 or the above second compound.

[0073] The third layer can be composed of at least one element selected from Group 1A consisting of Cr, Al, Ti, and Si, or can be composed of a second compound consisting 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, Al2O3, TiAlSiN, TiCrSiN, TiAlCrSiN, AlCrN, AlCrO, AlCrON, AlCrSiN, AlCrBN, TiZrN, TiAlMoN, TiAlNbN, TiSiN, AlCrTaN, AlVN, AlTiVN, TiB2, 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 effect of imparting lubricity by the third layer can be easily obtained. The upper limit of the thickness of the third layer is not particularly limited, but when it exceeds 2 μm, there is a tendency that the above-described effect of imparting lubricity cannot be further improved. Therefore, considering the cost aspect, the thickness of the third layer may be 2 μm or less.

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

[0077] [Embodiment 2: Method for manufacturing a cutting tool] In Embodiment 2, a method for manufacturing the cutting tool according to 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. As the substrate, the substrate described in Embodiment 1 can be used. Any conventionally known substrate can 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 layer is formed by alternately laminating a first unit layer and a second unit layer using a Physical Vapor Deposition (PVD) method. In order to improve the wear resistance of the coating including the first layer, it is highly effective to form a layer made of a highly crystalline compound. As a result of examining various methods as the method for forming the first layer, the present inventors have found that the use of a physical vapor deposition method is highly effective.

[0081] As the PVD method, at least one selected from the group consisting of a cathodic arc ion plating method, a balanced magnetron sputtering method, an unbalanced magnetron sputtering method, and a HiPIMS method can be used. In particular, a cathodic arc ion plating method with a high ionization rate of raw material elements may be used. When the cathodic arc ion plating method is used, since ion bombardment treatment of metal can be performed on the surface of the substrate before forming the first layer, the adhesion between the substrate and the coating including the first layer is remarkably improved.

[0082] The cathode arc ion plating method can be carried out, for example, by installing a substrate in a device and a target as a cathode, and then applying a high voltage to the target to generate an arc discharge to ionize and evaporate the atoms constituting the target, and depositing a substance on the substrate.

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

Example

[0084] This embodiment will be described more specifically by way of examples. However, this embodiment is not limited by these examples.

[0085] ≪Manufacture of cutting tool≫ FIG. 6 is a schematic cross-sectional view of the cathode arc ion plating apparatus used in this example, and FIG. 7 is a schematic top view of the apparatus of FIG. 6.

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

[0087] In the apparatus for a sample on which the second layer or the third layer is to be formed, a cathode (not shown) for the second layer or a cathode (not shown) for the third layer is further attached 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 described in Table 3 and Table 4 below.

[0088] An arc power source 108 is attached to the cathode 106, and an arc power source 109 is attached to the cathode 107. Also, a bias power source 110 is attached to the substrate holder 104. Further, in the chamber 101, a gas inlet for introducing the gas 105 is provided, and a gas outlet 103 is provided to adjust the pressure in the chamber 101, and the gas in the chamber 101 can be sucked by a vacuum pump from the gas outlet 103.

[0089] A substrate holder 104 was mounted with a four-flute radius end mill made of cemented carbide with a grade of JIS standard K20 as the substrate, having a diameter of 6 mm.

[0090] Next, the inside of the chamber 101 was evacuated by a vacuum pump, and while rotating the substrate, the temperature was heated to 500 °C by a heater installed in the apparatus, and the pressure in the chamber 101 was reduced to 1.0×10 -4 Pa by evacuation. Next, argon gas was introduced from the gas inlet to maintain the pressure in the chamber 101 at 2.0 Pa, the voltage of the bias power source 110 was gradually increased to -1000 V, and the surface of the substrate was cleaned for 15 minutes. Thereafter, the substrate was cleaned by exhausting argon gas from the chamber 101 (argon bombardment treatment). Thus, the substrates of the cutting tools for each sample were prepared.

[0091] Next, while rotating the substrate at the center and introducing nitrogen as the reaction gas, while maintaining the temperature of the substrate at 550°C, the reaction gas pressure at 2.0 Pa, and the voltage of the bias power supply 110 at a certain value in the range of -50 V to -300 V, an arc current of 150 A is supplied to each of the cathodes 106 and 107, respectively, to generate metal ions from the cathodes 106 and 107, and a first layer composed of a first unit layer and a second unit layer having the compositions shown in Table 1 and Table 2 below is formed on the substrate.

[0092] When the second layer is formed, after forming the second layer on the substrate, the first layer is formed on the second layer. The second layer was formed by the following procedure. The substrate temperature was set to 550°C and the gas pressure in the apparatus was set to 4.0 Pa. As the reaction gas, a mixed gas of nitrogen gas and argon gas was introduced. Then, an arc current of 150 A was supplied to the cathode electrode. By generating metal ions and the like from the arc evaporation source by the supply of the arc current, the second layer was formed.

[0093] When the third layer is formed, the third layer is formed on the first layer. The third layer was formed by the following procedure. The substrate temperature was set to 550°C and the gas pressure in the apparatus was set to 4.0 Pa. As the reaction gas, a mixed gas of nitrogen gas and argon gas, or a mixed gas of oxygen gas was introduced. Then, an arc current of 150 A was supplied to the cathode electrode. By generating metal ions and the like from the arc evaporation source by the supply of the arc current, the third layer was formed.

[0094] Thus, cutting tools for each sample were fabricated.

[0095]

Table 1

[0096]

Table 2

[0097]

Table 3

[0098]

Table 4

[0099] ≪Evaluation≫ <Measurement of the compositions of the first unit layer and the second unit layer> For the cutting tools of each sample, the compositions of the first unit layer and the second unit layer were measured by the method described in Embodiment 1. The first unit layer Al a Ti (1-a-b) Si b N, and the second unit layer Al c Cr (1-c-d) Ag d The values of a, b, c, and d in N, and b / d are shown in Tables 1 and 2. Further, b / d is shown in Tables 1 and 2.

[0100] <Measurement of the composition of the second layer and the composition of the third layer> For the cutting tools of each sample, the compositions of the second layer and the third layer were measured by the method described in Embodiment 1. The results are shown in Tables 3 and 4. When it is described as "-", it means that the corresponding layer does not exist.

[0101] <Measurement of 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> For the cutting tools of each sample, 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 the cutting tools of each sample, 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 first unit layer and the second unit layer adjacent to each other was determined by the method described in Embodiment 1. The obtained results are shown in Tables 1 and 2.

[0103] <Measurement of the number of layers> For the cutting tools of each sample, the total number of stacked layers of the first unit layer and the second unit layer was determined by the method described in Embodiment 1. The results are shown in Tables 1 and 2. For example, a stacking number of 100 indicates that 50 layers of the first unit layer and 50 layers of the second unit layer are stacked. A stacking number of 667 indicates that 334 layers of the first unit layer and 333 layers of the second unit layer are stacked.

[0104] <Crystal structure of the coating> For the cutting tools of each sample, the crystal structure of the coating was analyzed by the method described in Embodiment 1. In Samples 1 to 27, the crystal structure was cubic.

[0105] <Hardness of the coating> For the cutting tools of each sample, the hardness of the coating was analyzed by the method described in Embodiment 1. In Samples 1 to 27, the hardness of the coating was 30 GPa or more and 50 GPa or less.

[0106] <Cutting test> A side machining test was performed using the cutting tools of each sample, 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 Tables 3 and 4. A longer cutting distance indicates a longer tool life. ≪Cutting conditions≫ Workpiece material: Inconel 718 Cutting speed Vc: 70 m / min Feed per tooth fz: 0.05 mm / tooth Depth of cut: ap = 3.0 mm, ae = 1.0 mm External lubrication available The above cutting conditions are applicable to the high-efficiency machining of nickel-based alloys.

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

[0108] Although the embodiments and examples of the present disclosure have been described as above, it has been planned from the beginning to appropriately combine or variously modify the configurations of the above-described embodiments and examples. The embodiments and examples disclosed this time should be considered illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the above-described embodiments and examples, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0109] 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 source, 110 Bias power source.

Claims

1. A cutting tool comprising a substrate and a coating disposed on the substrate, wherein the coating includes a first layer, the first layer consists of an alternating layer in which a first unit layer and a second unit layer are alternately laminated, The first unit layer is composed of Al ａ Ti （１－ａ－ｂ） Si ｂ and N The second unit layer is Al ｃ Cr （１－ｃ－ｄ） Ag ｄ and consists of N wherein a, b, c, and d are 0.50 ≤ a ≤ 0.75, 0.005 ≤ b ≤ 0.20, 0.50 ≤ c ≤ 0.85, and 0.005 ≤ d < 0.10 are satisfied, the average thickness of the first unit layer is 2 nm or more and 50 nm or less, the average thickness of the second unit layer is 2 nm or more and 50 nm or less, a cutting tool.

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

3. In the first unit layer and the second unit layer adjacent to the first unit layer, the ratio λ1 / λ2 of the thickness λ1 of the first unit layer to the thickness λ2 of the second unit layer is greater than 1.0, the cutting tool according to claim 1 or claim 2.

4. The cutting tool according to claim 1 or claim 2, wherein the thickness of the first layer is 0.5 μm or more and 10 μm or less.

5. The coating further includes a second layer provided between the substrate and the first layer, the second layer consists of at least one element selected from the first group consisting of group 4 elements, group 5 elements, group 6 elements, aluminum, and silicon in the periodic table, or consists of a first compound composed of at least one element selected from the first group and at least one element selected from the second group consisting of carbon, nitrogen, oxygen, and boron, the cutting tool according to claim 1 or claim 2.

6. The coating further includes a third layer disposed on the opposite side of the first layer from the substrate, the third layer consists of at least one element selected from the first group consisting of group 4 elements, group 5 elements, group 6 elements, aluminum, and silicon in the periodic table, or consists of a second compound composed of at least one element selected from the first group and at least one element selected from the second group consisting of carbon, nitrogen, oxygen, and boron, the cutting tool according to claim 1 or claim 2.

7. The cutting tool according to claim 1 or claim 2, wherein the thickness of the coating is 0.5 μm or more and 12 μm or less.

8. The cutting tool according to claim 1 or claim 2, 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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