Cutting tool

Abstract

A cutting tool provided with a base material and a coating film disposed on the base material, the coating film including a first layer comprising an alternating layer in which first unit layers and second unit layers are alternately laminated, the first unit layers having a hexagonal crystal structure, the first unit layers comprising W (C1-aNa) x, a being 0.3-0.8 inclusive, a being 0.5-0.8 inclusive, and a being 0.5-0.8 inclusive. X is from 0.8 to 1.2 (inclusive), the second unit layer is composed of AlcCr1-cN, and c is from 0.40 to 0.80 (inclusive).

Description

Technical Field

[0001] The present disclosure relates to cutting tools. Background Art

[0002] Conventionally, cutting tools having a substrate and a coating disposed on the substrate have been used for cutting (Patent Document 1 and Patent Document 2).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-143690

[0006] Patent Document 2: International Publication No. 2022 / 176230

[0007] Disclosed content

[0008] The cutting tool according to one aspect of the present disclosure includes a substrate and a coating disposed on the substrate, wherein

[0009] the coating includes a first layer,

[0010] the first layer is composed of an alternating layer formed by alternately laminating a first unit layer and a second unit layer,

[0011] the first unit layer has a hexagonal crystal structure,

[0012] the first unit layer is composed of W(C 1-a N a ) x and,

[0013] a is 0.3 or more and 0.8 or less,

[0014] x is 0.8 or more and 1.2 or less,

[0015] the second unit layer is composed of Al c Cr 1-c N,

[0016] and c is 0.40 or more and 0.80 or less. Brief Description of the Drawings

[0017] Figure 1 is a schematic enlarged cross-sectional view of an example of the cutting tool according to Embodiment 1.

[0018] Figure 2 is a schematic enlarged cross-sectional view of another example of the cutting tool according to Embodiment 1.

[0019] Figure 3It is a schematic enlarged cross-sectional view of another example of the cutting tool according to Embodiment 1.

[0020] Figure 4 It is a schematic enlarged cross-sectional view of another example of the cutting tool according to Embodiment 1.

[0021] Figure 5 It is a diagram for explaining an example of the thickness ratio between the first unit layer and the second unit layer.

[0022] Figure 6 It is a schematic enlarged cross-sectional view of an example of the cutting tool according to Embodiment 2.

[0023] Figure 7 It is a schematic enlarged cross-sectional view of another example of the cutting tool according to Embodiment 2.

[0024] Figure 8 It is a schematic enlarged cross-sectional view of another example of the cutting tool according to Embodiment 2.

[0025] Figure 9 It is a schematic enlarged cross-sectional view of another example of the cutting tool according to Embodiment 2.

[0026] Figure 10 It is a diagram for explaining an example of the thickness ratio between the first unit layer and the third unit layer.

[0027] Figure 11 It is a schematic cross-sectional view of the cathodic arc ion plating apparatus used in the examples.

[0028] Figure 12 is Figure 11 a schematic top view of the cathodic arc ion plating apparatus shown. Detailed implementation manners

[0029] [Problems to be solved by the present disclosure]

[0030] Cutting also plays a central role in manufacturing technology, and the evolution and further sophistication of technology have been required. In cutting technology, high-speed, high-efficiency, high-precision processing and ultra-fine processing are basically required. As a recent trend, there is a trend of difficult cutting of cut materials, and it is also required to respond to this situation. On this basis, in the field of cutting, in order to achieve a sustainable and better world by 2030, the attention to SDGs (Sustainable Development Goals) has been increasing in recent years. Sustainable development refers to the construction of a social foundation that can withstand the threat of nature without damaging the resources needed by future generations. Through the improvement of cutting technology, it can be expected that the environmental load will be reduced, such as power saving during product manufacturing due to the reduction of processes, and the reduction of waste associated with cutting. Based on this background, in order to extend the life of the tool, the development of coated tool materials with high high temperature hardness and both hardness and toughness is aimed at.

[0031] In the past, as a type of coated tool material, a nitride or boronitride film with Al and Cr as the main components was coated on the surface of the substrate (Patent Document 1 and Patent Document 2). However, from the perspective of SDGs and global environmental protection, there is a tendency for the tip temperature of the cutting tool to become high during cutting due to the requirement for dry machining without using cutting oil, the higher cutting speed to improve machining efficiency, the diversification of cut materials, and the increase in cutting of heat-resistant alloys and titanium alloys, which are called difficult-to-cut materials in the fields of aircraft and medicine. If the tip temperature becomes high, the life of the cutting tool becomes extremely short. Therefore, a cutting tool that can show excellent tool life even under such harsh cutting conditions is required.

[0032] [Effects of the present disclosure]

[0033] According to the present disclosure, it is possible to provide a cutting tool having a long tool life even in cutting processing performed under conditions where the cutting edge temperature is high.

[0034] [Description of Embodiments of the Present Disclosure]

[0035] First, embodiments of the present disclosure will be described below.

[0036] (1) A cutting tool according to one aspect of the present disclosure includes a substrate and a coating disposed on the substrate, wherein:

[0037] The coating comprises a first layer,

[0038] The first layer is composed of alternating layers formed by alternating first unit layers and second unit layers.

[0039] The first unit layer has a crystal structure of hexagonal crystal form.

[0040] The first unit layer is composed of W(C 1-a N a ), x wherein

[0041] a is not less than 0.3 and not more than 0.8,

[0042] x is not less than 0.8 and not more than 1.2.

[0043] The second unit layer is composed of Al c Cr 1-c N,

[0044] wherein c is not less than 0.40 and not more than 0.80.

[0045] According to the present disclosure, a cutting tool having a long tool life especially in cutting machining performed under conditions of a high cutting edge temperature can be provided.

[0046] (2) On the basis of (1) above, it is also possible that in the first unit layer and the second unit layer adjacent to the first unit layer, the ratio λ2 / λ1 of the thickness λ2 μm of the second unit layer to the thickness λ1 μm of the first unit layer is not less than 1.0 and not more than 5.0. Thus, the cutting tool can have a longer tool life.

[0047] (3) On the basis of (1) or (2) above, it is also possible that

[0048] the average thickness of the first unit layer is not less than 0.002 μm and not more than 0.2 μm,

[0049] the average thickness of the second unit layer is not less than 0.002 μm and not more than 0.2 μm.

[0050] Thus, the cutting tool can have a longer tool life.

[0051] (4) On the basis of any one of (1) to (3) above, it is also possible that

[0052] the coating film further includes a second layer disposed between the substrate and the first layer,

[0053] and the composition of the second layer is the same as the composition of the first unit layer or the composition of the second unit layer.

[0054] Thus, the cutting tool can have a longer tool life.

[0055] (5) On the basis of (4) above, it is also possible that

[0056] The composition of the second layer is the same as that of the first unit layer,

[0057] and the thickness of the second layer is thicker than that of the first unit layer.

[0058] Thus, the cutting tool can have a longer tool life.

[0059] (6) Based on the above (4), it can also be that

[0060] the composition of the second layer is the same as that of the second unit layer,

[0061] and the thickness of the second layer is thicker than that of the second unit layer.

[0062] Thus, the cutting tool can have a longer tool life.

[0063] (7) Based on the above (1) to (6), it can also be that

[0064] the coating film further includes a third layer provided on the side of the first layer opposite to the base material,

[0065] and the third layer is composed of AlCrCN.

[0066] Thus, the cutting tool can have a longer tool life.

[0067] (8) The cutting tool according to another aspect of the present disclosure includes a base material and a coating film disposed on the base material, wherein

[0068] the coating film includes a first A layer,

[0069] the first A layer is composed of an alternating layer formed by alternately laminating a first unit layer and a third unit layer,

[0070] the first unit layer has a hexagonal crystal structure,

[0071] the first unit layer is composed of W(C 1-a N a ) x wherein a is 0.3 or more and 0.8 or less,

[0072] x is 0.8 or more and 1.2 or less,

[0073] the third unit layer is composed of Al

[0074] d Cr 1-d-e M e N,

[0075] and M is silicon, boron, yttrium, cerium or lanthanum,

[0076] d is 0.40 or more and 0.80 or less,

[0077] e is greater than 0 and 0.05 or less.

[0078] According to the present disclosure, there can be provided a cutting tool having a long tool life especially in cutting operations performed under conditions of high nose temperature.

[0079] (9) On the basis of the above (8), it may also be that in the first unit layer and the third unit layer adjacent to the first unit layer, the ratio λ3 / λ1 of the thickness λ3 μm of the third unit layer to the thickness λ1 μm of the first unit layer is 1.0 or more and 5.0 or less.

[0080] Thereby, the cutting tool can have a longer tool life.

[0081] (10) On the basis of the above (8) or (9), it may also be that M is silicon.

[0082] Thereby, the cutting tool can have a longer tool life.

[0083] (11) On the basis of the above (8) or (9), it may also be that M is boron.

[0084] Thereby, the cutting tool can have a longer tool life.

[0085] (12) On the basis of any one of the above (8) to (11), it may also be that

[0086] the average thickness of the first unit layer is 0.002 μm or more and 0.2 μm or less,

[0087] the average thickness of the third unit layer is 0.002 μm or more and 0.2 μm or less.

[0088] Thereby, the cutting tool can have a longer tool life.

[0089] (13) On the basis of any one of the above (8) to (12), it may also be that

[0090] the coating film further includes a 2A layer disposed between the base material and the 1A layer,

[0091] the composition of the 2A layer is the same as the composition of the first unit layer or the composition of the third unit layer.

[0092] Thereby, the cutting tool can have a longer tool life.

[0093] (14) On the basis of the above (13), it may also be that

[0094] The composition of the 2A layer is the same as that of the first unit layer,

[0095] and the thickness of the 2A layer is thicker than that of the first unit layer.

[0096] Thus, the cutting tool can have a longer tool life.

[0097] (15) Based on the above (13), it can also be that

[0098] the composition of the 2A layer is the same as that of the third unit layer,

[0099] and the thickness of the 2A layer is thicker than that of the third unit layer.

[0100] Thus, the cutting tool can have a longer tool life.

[0101] (16) Based on any one of the above (8) to (15), it can also be that

[0102] the coating film further includes a 3A layer provided on the side of the 1A layer opposite to the base material,

[0103] the 3A layer is composed of AlCrMeCN,

[0104] wherein Me is silicon, boron, yttrium, cerium or lanthanum.

[0105] Thus, the cutting tool can have a longer tool life.

[0106] [Details of the embodiments of the present disclosure]

[0107] Hereinafter, specific examples of the cutting tool of the present disclosure will be described with reference to the drawings. In the drawings of the present disclosure, the same reference numerals denote the same parts or corresponding parts. In addition, dimensional relationships such as length, width, thickness, depth, etc. are appropriately changed for the clarity and simplification of the drawings, and do not necessarily represent actual dimensional relationships.

[0108] In the present disclosure, the expression in the form of "A to B" means the upper and lower limits of the range (that is, A or more and B or less). When there is no unit description for A and only a unit is described for B, the unit of A is the same as that of B.

[0109] In the present disclosure, when representing a compound or the like by a chemical formula, when the atomic ratio is not particularly limited, it includes all the atomic ratios known in the past, and is not necessarily limited to the atomic ratio within the stoichiometric range.

[0110] In the present disclosure, when one or more numerical values are respectively described as the lower limit and the upper limit of a numerical range, it is considered that combinations of any one of the numerical values described as the lower limit and any one of the numerical values described as the upper limit are also disclosed. For example, when a1 or more, b1 or more, c1 or more are described as the lower limit, and a2 or less, b2 or less, c2 or less are described as the upper limit, it is considered that a1 or more and a2 or less, a1 or more and b2 or less, a1 or more and c2 or less, b1 or more and a2 or less, b1 or more and b2 or less, b1 or more and c2 or less, c1 or more and a2 or less, c1 or more and b2 or less, c1 or more and c2 or less are disclosed.

[0111] [Embodiment 1: Cutting Tool (1)]

[0112] Using Figures 1 - 5 , a cutting tool according to an embodiment of the present disclosure will be described.

[0113] A cutting tool 1 according to an embodiment of the present disclosure (hereinafter, also referred to as "Embodiment 1".) includes a substrate 2 and a coating film 3 disposed on the substrate 2, wherein

[0114] The coating film 3 includes a first layer 13,

[0115] The first layer 13 is composed of an alternating layer formed by alternately laminating a first unit layer 12 and a second unit layer 15,

[0116] The first unit layer 12 has a hexagonal crystal structure,

[0117] The first unit layer 12 is composed of W(C 1-a N a ) x constituting,

[0118] a is 0.3 or more and 0.8 or less,

[0119] x is 0.8 or more and 1.2 or less,

[0120] The second unit layer 15 is composed of Al c Cr 1-c N,

[0121] c is 0.40 or more and 0.80 or less.

[0122] The cutting tool 1 of Embodiment 1 can have a long tool life especially in cutting operations performed under conditions of high tool tip temperature. The reason is speculated as follows.

[0123] The first unit layer 12 is composed of W(C 1-a N a ) xComposition. The first unit layer 12 contains C (carbon), so the coefficient of friction at the contact interface with the material to be cut is reduced, and the cutting resistance can be lowered. Additionally, W(C 1-a N a ) x contains N (nitrogen), so the heat resistance is improved by about 150 °C compared to WC. As a result, the first layer containing the first unit layer can improve the adhesion resistance, slidability, and abrasion resistance during machining where the cutting edge becomes hot, such as in dry cutting. Therefore, the tool life of the cutting tool containing the first layer is increased.

[0124] The second unit layer 15 is composed of Al c Cr 1-c N. The second unit layer 15 contains Al. Since Al is easily oxidized, the coating film containing the second unit layer 12 has a tendency to easily form a dense oxide layer composed of Al 2 O 3 on the surface side of the first layer 13. As a result, the heat blocking property and oxidation resistance of the first layer 13 can be improved. Therefore, the tool life of the cutting tool containing the first layer 13 is increased.

[0125] The first layer 13 is composed of an alternating layer formed by alternately laminating the first unit layer 12 and the second unit layer 15. At the interface between the first unit layer 12 and the second unit layer 15, the composition and crystal lattice are discontinuous. Therefore, when cracks occur on the surface of the coating film 3 during cutting, the progress of the cracks can be suppressed at the interface. In the coating film containing the first layer, chipping and defects are suppressed. Therefore, the tool life of the cutting tool containing the first layer 13 is increased.

[0126] <Cutting Tool>

[0127] As Figure 1 and Figure 2 shown, the cutting tool 1 according to an embodiment of the present invention includes a substrate 2 and a coating film 3 disposed on the substrate 2. The coating film 3 can cover at least the part of the substrate 2 that participates in cutting. The coating film 3 can also cover the entire surface of the substrate 2. Even if the composition of the coating film 3 is locally different, it does not deviate from the scope of this embodiment. In this specification, the part of the substrate 2 that participates in cutting refers to the area within at least 50 μm, 100 μm, or 300 μm from the cutting edge ridge line on the surface of the substrate 2.

[0128] The cutting tool 1 of this embodiment can preferably be used as cutting tools 1 such as drills, end mills, indexable cutting inserts for drills, indexable cutting inserts for end mills, indexable cutting inserts for milling, indexable cutting inserts for turning, metalworking saws, gear cutting tools, reamers, taps, etc.

[0129] <Substrate>

[0130] As the substrate 2, any substrate can be used as long as it is a conventionally well-known substrate. For example, the substrate 2 can be composed of cemented carbide (WC-based cemented carbide, cemented carbide containing WC and Co, cemented carbide added with carbonitrides such as Ti, Ta, Nb to WC and Co, etc.), cermet (cermet mainly composed of TiC, TiN, TiCN, etc.), high-speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, alumina, etc.), cubic boron nitride sintered body or diamond sintered body.

[0131] In particular, the substrate 2 can also be WC-based cemented carbide or cermet (especially TiCN-based cermet). WC-based cemented carbide or cermet has excellent balance between hardness and strength especially at high temperatures. Therefore, when used as the substrate 2 of the cutting tool 1, it can contribute to the long life of the cutting tool 1.

[0132] <Coating film>

[0133] The coating film 3 of Embodiment 1 includes the first layer 13. By coating the substrate 2, the coating film 3 has the effect of improving various properties such as wear resistance and chipping resistance of the cutting tool 1, and bringing about the long life of the cutting tool 1.

[0134] On the basis of the first layer 13, the coating film 3 can further include other layers. As Figure 3 and Figure 4 shown, as other layers, the second layer 16 disposed between the substrate 2 and the first layer 13, and the third layer 14 provided on the side of the first layer 13 opposite to the substrate 2 can be cited, etc.

[0135] The overall thickness of the coating film 3 can be 0.4 μm or more and 15 μm or less. If the overall thickness of the coating film 3 is 0.4 μm or more, it is easy to obtain the effect of making the life of the cutting tool 1 longer by providing the coating film 3. On the other hand, if the overall thickness of the coating film 3 is 15 μm or less, chipping at the coating film 3 is not likely to occur at the initial stage of cutting, and the life of the cutting tool 1 can be made longer.

[0136] The overall thickness of the coating film 3 can be measured by observing the cross-section of the coating film 3 using a scanning electron microscope (SEM). The specific measurement method is as follows. Cut the cutting tool 1 in the direction normal to the surface of the coating film 3 to prepare a cross-section sample. Observe the cross-section sample using SEM. Set the observation magnification to 5000 - 10000 times, and set the measurement field of view to 100 - 500 μm 2The thickness ranges of three parts of the coating film 3 are measured in one visual field, and the average value of the thickness ranges of the three parts is calculated. This average value corresponds to the thickness of the coating film 3. Regarding the thickness of each layer described later, unless otherwise specified, it is measured in the same manner.

[0137] The absolute value of the compressive residual stress of the coating film 3 can be 6 GPa or less. The compressive residual stress of the coating film 3 is a kind of internal stress (inherent strain) existing in the whole coating film 3, and is a stress represented by a "-" (negative) value (unit: "GPa" is used in this embodiment). Therefore, the concept of a large compressive residual stress means that the absolute value of the numerical value becomes larger, and the concept of a small compressive residual stress means that the absolute value of the numerical value becomes smaller. That is, the absolute value of the compressive residual stress being 6 GPa or less means that the compressive residual stress of the coating film 3 is -6 GPa or more and 0 GPa or less.

[0138] If the compressive residual stress of the coating film 3 is 0 GPa or less, it is easy to suppress the progress of cracks generated from the outermost surface of the coating film 3. On the other hand, if the absolute value of the compressive residual stress is 6 GPa or less, the magnitude of the stress is appropriate, and it is easy to suppress the peeling of the coating film 3 from the edge portion of the cutting tool 1 before the start of cutting.

[0139] The compressive residual stress of the coating film 3 is measured by the sin 2 ψ method (pages 54 - 66 of "X-ray Stress Measurement Method" (The Japan Institute of Metals, published by Yoshikien Co., Ltd. in 1981)).

[0140] The first unit layer 12 can have a hexagonal crystal structure. If the first unit layer 12 has a hexagonal crystal structure, the wear resistance of the coating film 3 is improved. The second unit layer 15 can contain a cubic crystal structure. If the second unit layer 15 has a cubic crystal structure, the hardness of the coating film 3 is increased. The crystal structure of each layer in the coating film 3 can be analyzed by an X-ray diffractometer well-known in the art.

[0141] The hardness of the coating film 3 is highly effective when it is 30 GPa or more and 55 GPa or less, and can also be 35 GPa or more and 50 GPa or less. Thus, the coating film 3 has sufficient hardness. The hardness of the whole coating film 3 is measured by the nanoindentation method (Nano Indenter XP manufactured by MTS Corporation). Specifically, it is carried out according to the method of ISO14577, the measurement load is set to 10 mN (1 gf), the hardness of three parts on the surface of the coating film 3 is measured, and the average value of the hardness of the three parts is calculated. This average value corresponds to the hardness of the coating film 3.

[0142] <First layer>

[0143] The first layer 13 of the present embodiment is composed of an alternating layer formed by alternately laminating a first unit layer 12 and a second unit layer 15. The fact that the first layer 13 is composed of an alternating layer formed by alternately laminating the first unit layer 12 and the second unit layer 15 can be confirmed by observing a thin film sample including the coating film 3 in cross section using a TEM (transmission electron microscope) and based on the difference in contrast.

[0144] Either the first unit layer 12 or the second unit layer 15 can be disposed at the position closest to the substrate 2 side. In Figure 1 , the first unit layer 12 is disposed directly above the substrate 2. In Figure 2 , the second unit layer 15 is disposed directly above the substrate 2. Either the first unit layer 12 or the second unit layer 15 can be disposed on the surface side of the coating film 3. In Figure 1 , the second unit layer 15 is disposed on the surface side of the coating film 3. In Figure 2 , the first unit layer 12 is disposed on the surface side of the coating film 3.

[0145] The thickness of the first layer 13 can be 0.5 μm or more and 15 μm or less. If the thickness of the first layer 13 is 0.5 μm or more, excellent abrasion resistance can be exhibited in continuous machining. If the thickness of the first layer 13 is 15 μm or less, excellent chipping resistance can be exhibited in interrupted cutting.

[0146] The thickness of the first layer 13 is measured by observing the cross section of the coating film 3 using a transmission electron microscope (TEM). The specific measurement method is as follows. The cutting tool 1 is cut in the direction normal to the surface of the coating film 3, and a thin film sample including the cross section of the coating film 3 is prepared. The thin film sample is observed using a TEM. The observation magnification is set to 20,000 to 5,000,000 times, and the measurement field of view is set to 0.0016 to 80 μm 2 . The thickness ranges of three portions of the first layer 13 are measured in one field of view, and the average value of the thickness ranges of the three portions is calculated. This average value corresponds to the thickness of the first layer 13.

[0147] The first unit layer 12 may have a hexagonal crystal structure. The hexagonal crystal structure comes from W(C 1-a N a ) x that constitutes the first unit layer 12. The fact that the first unit layer 12 has a hexagonal crystal structure can be confirmed by analysis using XRD measurement. In the obtained XRD pattern, ε-W 2 C (01-076-7103) and W 4.6 N 4In the case of the peak of the hexagonal crystal form defined by (01-077-2001), it is confirmed that the first unit layer 12 has a crystal structure of the hexagonal crystal form.

[0148] When the coating film includes other layers such as the second unit layer 15, the second layer 16, the third layer 14, and the intermediate layer together with the first unit layer, and peaks from layers other than the first unit layer 12 and the substrate are detected in the XRD pattern starting from the surface of the coating film 3 (hereinafter, also referred to as "other peaks"), it is possible to identify that the first unit layer 12 has a crystal structure of the hexagonal crystal form.

[0149] As the device for X-ray diffraction measurement, "SmartLab" (trade name) manufactured by Rigaku Corporation can be cited. The conditions for XRD measurement are as described below.

[0150] (XRD measurement conditions)

[0151] Scanning axis: 2θ-θ

[0152] X-ray source: Cu-Kα line

[0153] Detector: zero-dimensional detector (scintillation counter)

[0154] Tube voltage: 45 kV

[0155] Tube current: 40 mA

[0156] Incident optical system: utilization of a mirror

[0157] Receiving optical system: utilization of an analyzer crystal (PW3098 / 27)

[0158] Step size: 0.03°

[0159] Accumulation time: 2 seconds

[0160] Scanning range (2θ): 10° to 120°

[0161] <Composition of the first unit layer and composition of the second unit layer>

[0162] The first unit layer 12 is composed of W(C 1-a N a )x, where a is 0.3 or more and 0.8 or less, and x is 0.8 or more and 1.2 or less. Thus, the crystal structure of the first unit layer 12 becomes the hexagonal crystal form, and the heat resistance, oxidation resistance, and abrasion resistance of the first unit layer 12 can be improved.

[0163] The lower limit of a is 0.3 or more, may be 0.35 or more, may be 0.40 or more, and may also be 0.45 or more. The upper limit of a is 0.8 or less, may be 0.75 or less, may be 0.70 or less, and may also be 0.65 or less. a may be 0.35 or more and 0.75 or less, may be 0.40 or more and 0.70 or less, and may also be 0.45 or more and 0.65 or less.

[0164] The lower limit of x is 0.8 or more, may be 0.85 or more, and may also be 0.90 or more. The upper limit of x is 1.2 or less, may be 1.15 or less, and may also be 1.10 or less. x may be 0.85 or more and 1.15 or less, may be 0.90 or more and 1.10 or less, and may also be 1.00.

[0165] In the present disclosure, "the first unit layer is composed of W(C 1-a N a )x" means that as long as the effects of the present disclosure are not impaired, the first unit layer 12 may further contain inevitable impurities on the basis of W(C 1-a N a )x. Examples of the inevitable impurities include oxygen and carbon. The overall content rate of the inevitable impurities in the first unit layer 12 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 of the atoms constituting the layer.

[0166] The second unit layer 15 is composed of Al c Cr 1-c N, and c is 0.40 or more and 0.80 or less. The second unit layer 15 can improve the heat resistance, oxidation resistance, and toughness of the coating film 3. The lower limit of c is 0.40 or more, may be 0.45 or more, may be 0.50 or more, and may also be 0.55 or more. The upper limit of c is 0.80 or less, may be 0.75 or less, may be 0.70 or less, and may also be 0.65 or less. c may be 0.45 or more and 0.75 or less, may be 0.50 or more and 0.70 or less, and may also be 0.55 or more and 0.65 or less.

[0167] In the present disclosure, "the second unit layer is composed of Al c Cr 1-c N" means that as long as the effects of the present disclosure are not impaired, the second unit layer 15 may contain inevitable impurities on the basis of Al c Cr 1-c N. Examples of the inevitable impurities include oxygen and carbon. The overall content rate of the inevitable impurities in the second unit layer 15 may be greater than 0 atomic% and less than 1 atomic%.

[0168] The content ratios of the above-mentioned a, the above-mentioned x, the above-mentioned c, and the inevitable impurities in the first unit layer 12 and the content ratio of the inevitable impurities in the second unit layer 15 are measured by performing elemental analysis on the cross-section of the coating film 3 using a transmission electron microscope (TEM). The specific measurement method is as described below. Cut the cutting tool 1 in the direction normal to the surface of the coating film 3 to prepare a thin film sample including the cross-section of the coating film 3. Using EDS (Energy Dispersive X-ray Spectroscopy) attached to the TEM, irradiate the thin film sample with an electron beam, measure the energy and the number of generated characteristic X-rays at this time, and perform elemental analysis on the first unit layer 12 and the second unit layer 15. Arbitrarily select 5 layers of the first unit layer 12 and the second unit layer 15 respectively for elemental analysis. Calculate the average composition of the 5 layers of the first unit layer 12. This average composition corresponds to the composition of the first unit layer 12. Calculate the average composition of the 5 layers of the second unit layer 15. This average composition corresponds to the composition of the second unit layer 15. When the number of layers of the first unit layer 12 and the second unit layer 15 is 4 layers or less, perform elemental analysis on all the layers, and calculate the average composition of the first unit layer 12 and the second unit layer 15. It is confirmed that as long as the measurement is performed on the same cutting tool 1, even if the measurement site is arbitrarily selected, there is no deviation in the measurement results.

[0169] In the present disclosure, in the composition W(C 1-a N a )x of the first unit layer, the total number of atoms A of C and N N1 relative to the number of atoms A of W M1 the ratio A N1 / A M1 is 0.8 or more and 1.2 or less. In the present disclosure, in the composition Al c Cr 1-c N of the second unit layer, the number of atoms A of N N2 relative to the total number of atoms A of Al and Cr M2 the ratio A N2 / A M2 is necessarily 0.8 or more and 1.2 or less in manufacturing. The ratio A N1 / A M1 and the ratio A N2 / A M2 can be measured by the Rutherford backscattering (RBS) method. It is confirmed that if the above ratios A N1 / A M1 and the ratio A N2 / A M2 are within the above ranges, the effects of the present disclosure are not impaired.

[0170] <Average thickness of the first unit layer and average thickness of the second unit layer>

[0171] The average thickness of the first unit layer 12 can be 0.002 μm or more and 0.2 μm or less, and the average thickness of the second unit layer 15 can be 0.002 μm or more and 0.2 μm or less. Thereby, the progress of cracks generated on the surface of the coating film 3 can be further suppressed. The lower limit of the average thickness of the first unit layer 12 can be 0.002 μm or more, can be 0.005 μm or more, or can be 0.01 μm or more. The upper limit of the average thickness of the first unit layer 12 can be 0.20 μm or less, can be 0.15 μm or less, or can be 0.10 μm or less. The average thickness of the first unit layer 12 can be 0.005 μm or more and 0.15 μm or less, or can be 0.01 μm or more and 0.1 μm or less. The lower limit of the average thickness of the second unit layer 15 can be 0.002 μm or more, can be 0.005 μm or more, or can be 0.01 μm or more. The upper limit of the average thickness of the second unit layer 15 can be 0.20 μm or less, can be 0.15 μm or less, or can be 0.10 μm or less. The average thickness of the second unit layer 15 can be 0.005 μm or more and 0.15 μm or less, or can be 0.01 μm or more and 0.10 μm or less.

[0172] The average thickness of the first unit layer 12 and the average thickness of the second unit layer 15 can be measured by the same method as the method for measuring the thickness of the first layer 13 described above.

[0173] As Figure 5 shown, in the first unit layer 12 and the second unit layer 15 adjacent to the first unit layer 12, the ratio λ2 / λ1 of the thickness λ2 μm of the second unit layer 15 to the thickness λ1 μm of the first unit layer 12 can be 1.0 or more and 5.0 or less. The second unit layer 15 has high oxidation resistance and low thermal conductivity, and has the property of being difficult to transfer the heat generated during cutting to the base material 2. If the ratio λ2 / λ1 is 1.0 or more, the proportion of the second unit layer 15 in the coating film 3 relatively increases, and the amount of Al in the coating film 3 increases, so that the heat blocking property of the cutting tool 1 as a whole is improved. The cutting tool 1 having the coating film 3 has improved wear resistance especially during continuous cutting. If λ2 / λ1 is 1.0 or more, there is a tendency for the toughness of the coating film 3 to increase. On the other hand, if λ2 / λ1 is 5.0 or less, there is a tendency for the suppression effect of the progress of cracks brought about by laminating the first unit layer 12 and the second unit layer 15 to be easily obtained.

[0174] λ2 / λ1 can be 1.0 or more, can be 1.1 or more, can be 1.2 or more, can be 1.3 or more, can be 1.4 or more, can be 1.5 or more, can be 2.0 or more, can be 2.5 or more. λ2 / λ1 can be 5.0 or less, can also be 4.0 or less, and can further be 3.0 or less. λ2 / λ1 can be 1.2 or more and 4.0 or less, and can also be 1.5 or more and 2.5 or less. In Figure 5 for illustration, the thicknesses of the three first unit layers 12 are all represented as λ1, and the thicknesses of the three second unit layers 15 are all represented as λ2. However, between the first unit layer and the second unit layer adjacent to each other, as long as the above relationship of λ2 / λ1 is satisfied, the thicknesses λ1 of the three first unit layers 12 do not need to be the same, and further, the thicknesses λ2 of the three second unit layers 15 do not need to be the same.

[0175] In the first layer 13, the number of stacked layers of the first unit layer 12 and the second unit layer 15 respectively can be 5 or more and 500 or less, and can also be 10 or more and 500 or less. Thus, by stacking the first unit layer 12 and the second unit layer 15, the effect of evenly improving the hardness and the compressive residual stress can be sufficiently obtained. In the first layer 13, the number of stacked layers of the first unit layer 12 and the second unit layer 15 respectively can be 100 or more and 400 or less, and can also be 200 or more and 350 or less.

[0176] In the first layer 13, the number of stacked layers of the first unit layer 12 and the second unit layer 15 respectively can be obtained by using a TEM (transmission electron microscope) to observe a thin film sample of the cross section of the coating film 3 at an observation magnification of 20,000 to 5,000,000 times.

[0177] <Second layer>

[0178] As Figure 3 and Figure 4 shown, the coating film 3 further includes a second layer 16 disposed between the base material 2 and the first layer 13, and the composition of the second layer 16 can be the same as the composition of the first unit layer 12 or the composition of the second unit layer 15. Thus, the adhesion between the base material 2 and the coating film 3 can be improved.

[0179] When the composition of the second layer 16 is the same as the composition of the first unit layer 12, even when the second layer 16 is exposed at the initial stage of cutting, the sliding characteristics of the second layer 16 are good, and thus the wear resistance can be improved.

[0180] When the composition of the second layer 16 is the same as that of the first unit layer 12, the thickness of the second layer 16 can be thicker than that of the first unit layer 12. Thus, the adhesion between the base material 2 and the coating film 3 can be further improved. In addition, even when the second layer 16 is exposed at the initial stage of cutting, the sliding characteristics of the second layer 16 are good, so the wear resistance can be improved. "The thickness of the second layer is thicker than that of the first unit layer" can also be expressed as "the thickness of the second layer is more than 1.0 times that of the first unit layer". The thickness of the second layer 16 can be 2.0 times or more, 4.0 times or more, or 10.0 times or more the thickness of the first unit layer 12. The thickness of the second layer 16 can be 500 times or less, 120 times or less, or 50 times or less the thickness of the first unit layer 12. The thickness of the second layer 16 can be 2.0 times or more and 500 times or less, 4.0 times or more and 120 times or less, or 10.0 times or more and 50 times or less the thickness of the first unit layer 12.

[0181] When the composition of the second layer 16 is the same as that of the first unit layer 12, the thickness of the second layer 16 can be 0.1 μm or more. If the thickness of the second layer 16 is less than 0.1 μm, there is a tendency that it is difficult to obtain the improvement effect of wear resistance brought by making the second layer 16 have the same composition as the first unit layer 12. When the composition of the second layer 16 is the same as that of the first unit layer 12, the thickness of the second layer 16 can be 0.3 μm or more, or 0.4 μm or more. The upper limit value of the thickness of the second layer 16 is not particularly limited, but if it is greater than 2 μm, grain coarsening occurs and grain boundaries are generated, so there is a tendency that it is difficult to obtain the improvement effect of wear resistance. Therefore, considering the cost aspect, the thickness of the second layer 16 can be set to 2 μm or less.

[0182] When the composition of the second layer 16 is the same as that of the first unit layer 12, as Figure 3 shown, the first unit layer 12 can also be laminated directly above the second layer 16. In addition, as Figure 4 shown, the second unit layer 15 can also be laminated directly above the second layer 16. When the composition of the second layer 16 is the same as that of the first unit layer 12 and the first unit layer 12 is laminated directly above the second layer 16, the second layer 16 and the first unit layer 12 have a continuous crystal structure.

[0183] When the composition of the second layer 16 is the same as that of the second unit layer 15, the thickness of the second layer 16 can also be thicker than the thickness of the second unit layer 15. Thus, the adhesion between the base material 2 and the coating film 3 can be further improved. In addition, even if the second layer 16 is exposed at the initial stage of cutting, oxidation starting from the interface between the base material 2 and the coating film 3 can be suppressed, and cutting heat can be blocked. "The thickness of the second layer is thicker than the thickness of the second unit layer" can be paraphrased as "the thickness of the second layer is greater than 1.0 times the thickness of the second unit layer". The thickness of the second layer 16 can be 2.0 times or more the thickness of the second unit layer 15, can be 4.0 times or more, and can also be 10.0 times or more. The thickness of the second layer 16 can be 500 times or less the thickness of the second unit layer 15, can be 120 times or less, and can also be 50 times or less. The thickness of the second layer 16 can be 2.0 times or more and 500 times or less the thickness of the second unit layer 15, can be 4.0 times or more and 120 times or less, and can also be 10.0 times or more and 50 times or less.

[0184] When the composition of the second layer 16 is the same as that of the second unit layer 15, the thickness of the second layer 16 can be 0.1 μm or more. If the thickness of the second layer 16 is less than 0.1 μm, there is a tendency that it is difficult to obtain the effect of suppressing oxidation starting from the interface between the base material 2 and the coating film 3 and the effect of blocking cutting heat brought about by making the second layer 16 have the same composition as the second unit layer 15. When the composition of the second layer 16 is the same as that of the second unit layer 15, the thickness of the second layer 16 can be 0.3 μm or more, and can also be 0.4 μm or more. The upper limit value of the thickness of the second layer 16 is not particularly limited, but if it is greater than 2 μm, crystal grains grow and grain boundaries are generated, and thus there is a tendency that it is difficult to further improve the above-mentioned oxidation suppression effect. Therefore, considering cost, the thickness of the second layer 16 can be set to 2 μm or less.

[0185] When the composition of the second layer 16 is the same as that of the second unit layer 15, as Figure 3 shown, the first unit layer 12 can be laminated directly above the second layer 16. In addition, as Figure 4 shown, the second unit layer 15 can be laminated directly above the second layer 16. When the composition of the second layer 16 is the same as that of the second unit layer 15, and when the second unit layer 15 is laminated directly above the second layer 16, the second layer 16 and the second unit layer 15 have a continuous crystal structure.

[0186] <Third layer>

[0187] As Figures 1 - 4As shown, the coating film 3 further includes a third layer 14 provided on the side of the first layer 13 opposite to the base material 2, and the third layer 14 can be composed of AlCrCN. Thus, the coefficient of friction of the coating film 3 can be reduced, and the long life of the cutting tool 1 can be achieved.

[0188] Generally speaking, compared with nitrides, carbonitrides tend to have a lower coefficient of friction with respect to the material to be cut. It is considered that such a reduction in the coefficient of friction is based on the contribution of carbon atoms. If the coating film 3 includes the third layer 14, the coefficient of friction of the coating film 3 with respect to the material to be cut is reduced, and the cutting tool 1 has a long life.

[0189] In the third layer 14, by adjusting the composition ratio of N and C, a predetermined color can be imparted. Thus, the appearance of the cutting tool 1 can be given design and recognition, and it becomes useful commercially.

[0190] The thickness of the third layer 14 can be 0.1 μm or more. If the thickness of the third layer 14 is 0.1 μm or more, it is easy to obtain the effect of imparting lubricity based on the third layer 14. On the other hand, the upper limit value of the thickness of the third layer 14 is not particularly limited, but if it is greater than 2 μm, there is a tendency that the effect of imparting the above lubricity cannot be further improved. Therefore, considering the cost aspect, the thickness of the third layer 14 can be set to 2 μm or less.

[0191] <Intermediate layer>

[0192] The coating film 3 may include an intermediate layer disposed between the second layer 16 and the first layer 13, or between the first layer 13 and the third layer 14. Examples of the intermediate layer include AlCrCeN, AlCrN, AlCrBN, AlCrSiN, AlCrYN, AlCrLaN, etc. The thickness of the intermediate layer can be 0.1 μm or more and 2 μm or less, can also be 0.3 μm or more and 1.5 μm or less, and can further be 0.4 μm or more and 1.0 μm or less.

[0193] [Embodiment 2: Cutting tool (2)]

[0194] Use Figures 6 - 10 , the cutting tool according to another embodiment of the present disclosure will be described.

[0195] The cutting tool 1 according to another embodiment of the present disclosure (hereinafter, also referred to as "Embodiment 2".) includes a base material 2 and a coating film 3 disposed on the base material 2, wherein,

[0196] The coating film 3 includes a first A layer 13A,

[0197] The first A layer 13A is composed of an alternating layer formed by alternately laminating a first unit layer 12 and a third unit layer 17,

[0198] The first unit layer has a crystal structure of hexagonal crystal form,

[0199] The first unit layer 12 is composed of W(C 1-a N a ) x and constitutes,

[0200] where a is 0.3 or more and 0.8 or less,

[0201] and x is 0.8 or more and 1.2 or less,

[0202] The third unit layer 17 is composed of Al d Cr 1-d-e M e N and constitutes,

[0203] where M is silicon, boron, yttrium, cerium or lanthanum,

[0204] where d is 0.40 or more and 0.80 or less,

[0205] and e is greater than 0 and 0.05 or less.

[0206] The cutting tool 1 according to Embodiment 1 can have a long tool life especially in cutting operations performed under conditions of high cutting-edge temperature. The reasons are presumed as follows.

[0207] The first unit layer 12 is composed of W(C 1-a N a ) x and constitutes. Since the first unit layer 12 contains C (carbon), the coefficient of friction at the contact interface with the material to be cut is reduced, and the cutting resistance can be decreased. In addition, since W(C 1-a N a ) x contains N (nitrogen), the heat resistance is improved by about 150 °C compared with WC. As a result, the first layer containing the first unit layer can improve the wear resistance in machining where the cutting edge becomes hot, such as in dry cutting operations. Therefore, the tool life of the cutting tool containing the first layer is increased.

[0208] In the case of comparing a layer composed of nitrides of Al and Cr (hereinafter, also referred to as "AlCrN layer") and a layer composed of nitrides containing Al, Cr, and M (M is silicon, boron, yttrium, cerium or lanthanum) (hereinafter, also referred to as "AlCrMN layer"), the AlCrMN layer is less likely to undergo spinodal decomposition of AlCrN at high temperatures. If spinodal decomposition occurs, soft hexagonal AlN precipitates and the hardness decreases. The AlCrMN layer suppresses hardness decrease even at high temperatures, has a large compressive residual stress, and has excellent chipping resistance. The AlCrMN layer has a high heat blocking property. The 1A layer 13A is composed of W(C 1-a Na ) x It is composed of an alternating layer formed by alternately laminating a first unit layer 12 composed of [layer material of the first unit layer] and a third unit layer 17 composed of an AlCrMN layer. Therefore, it can have the characteristics of high hardness and low friction coefficient of the first unit layer 12, and the characteristics of high heat blocking property of the third unit layer 17. The characteristic of large compressive residual stress of the third unit layer 17 is complemented by the small compressive residual stress of the first unit layer 12. Therefore, as the entire 1A layer 13A, the hardness, heat blocking property, and compressive residual stress are improved evenly, and the life of the cutting tool 1 including the 1A layer 13A becomes longer.

[0209] The 1A layer 13A is composed of an alternating layer formed by alternately laminating the first unit layer 12 and the third unit layer 17. At the interface between the first unit layer 12 and the third unit layer 17, the composition and crystal lattice are discontinuous. Therefore, when cracks are generated from the surface of the coating 3 during cutting, the progress of the cracks can be suppressed at this interface. Therefore, chipping and defect are suppressed, and the life of the cutting tool 1 becomes longer.

[0210] The cutting tool 1 of Embodiment 2 can be basically configured to be the same as the cutting tool 1 of Embodiment 1 except for the configurations of the 1A layer 13A, the 2A layer 16, and the 3A layer 14A. Hereinafter, the "1A layer", "2A layer", and "3A layer" will be described.

[0211] <The 1A layer>

[0212] The 1A layer 13A of the present embodiment is composed of an alternating layer formed by alternately laminating the first unit layer 12 and the third unit layer 17. The fact that the 1A layer 13A is composed of an alternating layer formed by alternately laminating the first unit layer 12 and the third unit layer 17 can be confirmed by observing the cross section of the coating 3 using TEM (transmission electron microscope) through the difference in contrast. The thickness of the 1A layer 13A can be set to the same configuration as the thickness of the first layer 13 described in Embodiment 1.

[0213] <Composition of the first unit layer and composition of the third unit layer>

[0214] The composition of the first unit layer 12 of Embodiment 2, W(C 1-a N a ) x can be set to be the same as the composition of the first unit layer 12 of Embodiment 1, W(C 1-a N a ) x identical.

[0215] The third unit layer 17 is composed of Al d Cr 1-d-e M e It should be noted that in the translation, the content in square brackets "[layer material of the first unit layer]" needs to be filled with the specific material of the first unit layer in the original text. If there is no specific information provided in the original text, it can be left blank or marked as such in the translation to indicate that it needs to be determined according to the actual situation. Also, the 7 - digit tags a , x , etc. are preserved as they are according to the requirements.It is composed of N, where M is silicon, boron, yttrium, cerium, or lanthanum, d is 0.40 or more and 0.80 or less, and e is greater than 0 and 0.05 or less. The third unit layer 17 can have both excellent hardness and excellent oxidation resistance. The reason is presumably as follows.

[0216] When M is silicon, the structure of the third unit layer 17 is refined, whereby the hardness and oxidation resistance of the third unit layer 17 are improved, and the hardness and oxidation resistance of the entire coating 3 are improved.

[0217] When M is boron, the hardness of the third unit layer 17 becomes high due to boron, and the hardness of the entire coating 3 becomes high. In addition, the oxide of boron formed by the oxidation of the surface of the cutting tool 1 during cutting densifies the oxide of Al in the third unit layer 17, and the oxidation resistance of the third unit layer 17 is improved. Furthermore, the oxide of boron has a low melting point, so it functions as a lubricant during cutting and can suppress the adhesion of the material to be cut.

[0218] When M is yttrium (Y), cerium (Ce), or lanthanum (La), the lattice constant of YN is The lattice constant of CeN is The lattice constant of LaN is The lattice constants of YN, CeN, and LaN are larger than the lattice constant of TiN and the lattice constant of AlN Therefore, strain is introduced into the third unit layer 17 composed of face-centered cubic Al d Cr 1-d-e M e N, and the structure is refined, the hardness and wear resistance of the third unit layer 17 are improved, and the life of the cutting tool 1 including the third unit layer 17 becomes longer.

[0219] The above d is 0.40 or more and 0.80 or less. Thus, the crystal structure of the third unit layer 17 becomes a face-centered cubic type, the third unit layer 17 becomes high-hardness, and the wear resistance is improved. The lower limit of d can be 0.45 or more, can also be 0.50 or more, and can also be 0.55 or more. The upper limit of d can be 0.75 or less, can also be 0.70 or less, and can also be 0.65 or less. d can be 0.45 or more and 0.75 or less, can also be 0.50 or more and 0.70 or less, and can also be 0.55 or more and 0.65 or less.

[0220] The above e is greater than 0 and 0.05 or less. Thus, the hardness and oxidation resistance of the first layer 13A can be improved. The lower limit of e can be 0.002 or more, can be 0.005 or more, can be 0.01 or more, and can be 0.02 or more. This e can be 0.04 or less, or can be 0.03 or less. e can be 0.002 or more and 0.05 or less, can be 0.01 or more and 0.05 or less, can be 0.01 or more and 0.03 or less, and can be 0.02 or more and 0.03 or less.

[0221] In the present disclosure, "the third unit layer is composed of Al d Cr 1-d-e M e N" means that as long as the effects of the present disclosure are not impaired, the third unit layer 17 may contain inevitable impurities on the basis of Al d Cr 1-d-e M e N. Examples of such inevitable impurities include oxygen and carbon. The total content of the inevitable impurities in the third unit layer 17 can be greater than 0 atomic % and less than 1 atomic %.

[0222] The above d, the above e, and the content rate of the inevitable impurities of the third unit layer 17 are obtained by the same method as the measurement method of the above a. In addition, it has been confirmed that as long as the measurement is performed in the same cutting tool 1, even if the measurement site is arbitrarily selected, there is no deviation in the measurement result.

[0223] In the present disclosure, in the composition W(C 1-a N a ) x of the first unit layer, the total number of atoms A N1 of C and N M1 is 0.8 or more and 1.2 or less with respect to the number of atoms A N1 of W. In the present disclosure, in the composition Al M1 of the third unit layer d Cr 1-d- e M e N, the number of atoms A N3 of N M3 is necessarily 0.8 or more and 1.2 or less with respect to the total number of atoms A N3 of Al, Cr, and M. The ratio A M3 and the ratio A N1 / A M1 and the ratio A N3 / A M3 can be measured by the Rutherford backscattering (RBS) method. It has been confirmed that if the above ratio A N1 / AM1 and more than A N3 / A M3 is within the above range, the effects of the present disclosure are not impaired.

[0224] <Average thickness of the first unit layer and average thickness of the third unit layer>

[0225] The average thickness of the first unit layer 12 can be 0.002 μm or more and 0.2 μm or less, and the average thickness of the third unit layer 17 can be 0.002 μm or more and 0.2 μm or less. Thereby, the progress of cracks generated on the surface of the coating film 3 can be further suppressed. The lower limit of the average thickness of the first unit layer 12 can be 0.002 μm or more, can be 0.005 μm or more, and can also be 0.01 μm or more. The upper limit of the average thickness of the first unit layer 12 can be 0.20 μm or less, can be 0.15 μm or less, and can also be 0.10 μm or less. The average thickness of the first unit layer 12 can be 0.005 μm or more and 0.15 μm or less, and can also be 0.01 μm or more and 0.1 μm or less. The lower limit of the average thickness of the third unit layer 17 can be 0.002 μm or more, can be 0.005 μm or more, and can also be 0.01 μm or more. The upper limit of the average thickness of the third unit layer 17 can be 0.20 μm or less, can be 0.15 μm or less, and can also be 0.10 μm or less. The average thickness of the third unit layer 17 can be 0.005 μm or more and 0.15 μm or less, and can also be 0.01 μm or more and 0.10 μm or less.

[0226] The average thickness of the first unit layer 12 and the average thickness of the third unit layer 17 can be obtained by the same method as the method for measuring the thickness of the first layer 13 described above.

[0227] As Figure 10 shown, in the first unit layer 12 and the third unit layer 17 adjacent to the first unit layer 12, the ratio λ3 / λ1 of the thickness λ3 of the third unit layer 17 to the thickness λ1 of the first unit layer 12 can be 1.0 or more and 5.0 or less. The third unit layer 17 has high oxidation resistance and low thermal conductivity, and has the property of not easily transferring the heat generated during cutting to the base material 2. If the ratio λ3 / λ1 is 1.0 or more, the proportion of the third unit layer 17 in the coating film 3 relatively increases, and the amount of Al in the coating film 3 increases, so that the heat blocking property of the cutting tool 1 as a whole is improved. The wear resistance of the cutting tool 1 having the coating film 3, especially during continuous cutting, is improved. If λ3 / λ1 is 1.0 or more, there is a tendency for the toughness of the coating film 3 to increase. On the other hand, if λ3 / λ1 is 5.0 or less, there is a tendency for the suppression effect of the progress of cracks caused by laminating the first unit layer 12 and the third unit layer 17 to be easily obtained.

[0228] λ3 / λ1 can be 1.0 or more, can be 1.1 or more, can be 1.2 or more, can be 1.3 or more, can be 1.4 or more, can be 1.5 or more, can be 2.0 or more. λ3 / λ1 can be 5.0 or less, can also be 4.0 or less, and can further be 3.0 or less. λ3 / λ1 can be 1.0 or more and 5.0 or less, can be 1.2 or more and 4.0 or less, can be 1.5 or more and 4.0 or less, can be 1.0 or more and 3.0 or less, can be 2.0 or more and 3.0 or less. In Figure 10 For illustration, the thicknesses of the three first unit layers 12 are all represented as λ1, and the thicknesses of the three third unit layers 17 are all represented as λ3. However, between the adjacent first unit layer and third unit layer, as long as the above relationship of λ3 / λ1 is satisfied, the thicknesses λ1 of the three first unit layers 12 do not need to be the same, and further, the thicknesses λ3 of the three third unit layers 17 do not need to be the same.

[0229] In the 1A layer 13A, the number of stacked layers of each of the first unit layer 12 and the third unit layer 17 can be 4 or more and 800 or less, and can also be 10 or more and 500 or less. Thus, by stacking the first unit layer 12 and the third unit layer 17, there is a tendency to easily obtain the effect of evenly improving hardness and compressive residual stress. In the 1A layer 13A, the number of stacked layers of each of the first unit layer 12 and the third unit layer 17 can be 100 or more and 400 or less, and can also be 200 or more and 350 or less.

[0230] In the 1A layer 13A, the number of stacked layers of each of the first unit layer 12 and the third unit layer 17 can be obtained by the same method as the measurement method of the number of stacked layers of the first unit layer 12 and the second unit layer 15 described in Embodiment 1.

[0231] <Second 2A layer>

[0232] As Figure 8 and Figure 9 shown, the coating film 3 further includes a 2A layer 16A disposed between the substrate 2 and the 1A layer 13A. The composition of the 2A layer 16A can be the same as the composition of the first unit layer 12 or the composition of the third unit layer 17. Thus, the adhesion between the substrate 2 and the coating film 3 can be improved.

[0233] When the composition of the 2A layer 16A is the same as the composition of the first unit layer 12, even when the 2A layer 16A is exposed at the initial stage of cutting, the sliding characteristics of the 2A layer 16A are good, and thus the wear resistance can be improved.

[0234] When the composition of the 2A layer 16A is the same as that of the first unit layer 12, the thickness of the 2A layer 16A can be greater than that of the first unit layer 12. Thereby, the adhesion between the base material 2 and the coating film 3 can be further improved. In addition, even when the 2A layer 16A is exposed at the initial stage of cutting, the sliding characteristics of the 2A layer 16A are good, so the wear resistance can be improved. "The thickness of the 2A layer is greater than that of the first unit layer" can also be expressed as "the thickness of the 2A layer is more than 1.0 times that of the first unit layer". The thickness of the 2A layer 16A can be 2.0 times or more, 4.0 times or more, or 10.0 times or more the thickness of the first unit layer 12. The thickness of the 2A layer 16A can be 500 times or less, 120 times or less, or 50 times or less the thickness of the first unit layer 12. The thickness of the 2A layer 16A can be 2.0 times or more and 500 times or less, 4.0 times or more and 120 times or less, or 10.0 times or more and 50 times or less the thickness of the first unit layer 12.

[0235] When the composition of the 2A layer 16A is the same as that of the first unit layer 12, the thickness of the 2A layer 16A can be 0.1 μm or more. If the thickness of the 2A layer 16A is less than 0.1 μm, there is a tendency that it is difficult to obtain the improvement effect of wear resistance brought about by making the 2A layer 16A have the same composition as the first unit layer 12. When the composition of the 2A layer 16A is the same as that of the first unit layer 12, the thickness of the 2A layer 16A can be 0.3 μm or more, or 0.4 μm or more. The upper limit value of the thickness of the 2A layer 16A is not particularly limited, but if it is greater than 2 μm, grain coarsening occurs and grain boundaries are generated, so there is a tendency that it is difficult to obtain the improvement effect of wear resistance. Therefore, considering cost, the thickness of the 2A layer 16A can be set to 2 μm or less.

[0236] When the composition of the 2A layer 16A is the same as that of the first unit layer 12, as Figure 8 shown, the first unit layer 12 can also be laminated directly above the 2A layer 16A. In addition, as Figure 9 shown, the second unit layer 15 can also be laminated directly above the 2A layer 16A. When the composition of the 2A layer 16A is the same as that of the first unit layer 12 and the first unit layer 12 is laminated directly above the 2A layer 16A, the 2A layer 16A and the first unit layer 12 have a continuous crystal structure.

[0237] When the composition of the 2A layer 16A is the same as that of the third unit layer 17, the third unit layer 17 tends to have small stress. Therefore, especially in interrupted machining such as milling and end milling where a load is repeatedly applied to the tool tip, the peel resistance of the coating film 3 can be improved.

[0238] When the composition of the 2A layer 16A is the same as that of the third unit layer 17, the thickness of the 2A layer 16A can be greater than that of the third unit layer 17. Thus, the adhesion between the base material 2 and the coating film 3 can be further improved. In addition, even if the 2A layer 16A is exposed at the initial stage of cutting, oxidation starting from the interface between the base material 2 and the coating film 3 can be suppressed, and cutting heat can be blocked. "The thickness of the 2A layer is greater than that of the third unit layer" can be paraphrased as "the thickness of the 2A layer is more than 1.0 times that of the third unit layer". The thickness of the 2A layer 16A can be 2.0 times or more, 4.0 times or more, or 10.0 times or more the thickness of the third unit layer 17. The thickness of the 2A layer 16A can be 500 times or less, 120 times or less, or 50 times or less the thickness of the third unit layer 17. The thickness of the 2A layer 16A can be 2.0 times or more and 500 times or less, 4.0 times or more and 120 times or less, or 10.0 times or more and 50 times or less the thickness of the third unit layer 17.

[0239] When the composition of the 2A layer 16A is the same as that of the third unit layer 17, the thickness of the 2A layer 16A can be 0.1 μm or more. If the thickness of the 2A layer 16A is less than 0.1 μm, there is a tendency that it is difficult to obtain the effect of suppressing oxidation starting from the interface between the base material 2 and the coating film 3 and the effect of blocking cutting heat brought about by making the 2A layer 16A have the same composition as the third unit layer 17. When the composition of the 2A layer 16A is the same as that of the third unit layer 17, the thickness of the 2A layer 16A can be 0.3 μm or more, or 0.4 μm or more. The upper limit value of the thickness of the 2A layer 16A is not particularly limited, but if it is greater than 2 μm, grain coarsening occurs and grain boundaries are generated, and thus there is a tendency that it is difficult to further improve the above-mentioned oxidation suppression effect. Therefore, considering cost, the thickness of the 2A layer 16A can be set to 2 μm or less.

[0240] When the composition of the 2A layer 16A is the same as that of the third unit layer 17, as Figure 8 shown, the first unit layer 12 can be laminated directly above the 2A layer 16A. In addition, as Figure 9 shown, the third unit layer 17 can be laminated directly above the 2A layer 16A. When the composition of the 2A layer 16A is the same as that of the third unit layer 17 and the third unit layer 17 is laminated directly above the 2A layer 16A, the 2A layer 16A and the third unit layer 17 have a continuous crystal structure.

[0241] <The 3A layer>

[0242] As Figures 6 - 9As shown, the coated film 3 further includes a 3A layer 14A provided on the side of the first layer 13 opposite to the base material 2, and the 3A layer 14A can be composed of AlCrMeCN. Here, Me can be silicon, boron, yttrium, cerium, or lanthanum. Me can be the same element as M used in the third unit layer. Thereby, the coefficient of friction of the coated film 3 is reduced, and the long life of the cutting tool 1 can be achieved.

[0243] Generally speaking, compared with nitrides, carbonitrides tend to have a lower coefficient of friction with respect to the material to be cut. It is considered that such a reduction in the coefficient of friction is based on the contribution of carbon atoms. If the coated film 3 includes the 3A layer 14A, the coefficient of friction of the coated film 3 with respect to the material to be cut is reduced, and the cutting tool 1 has a long life.

[0244] In the 3A layer 14A, by adjusting the composition ratio of N and C, a predetermined color can be imparted. Thereby, the appearance design and recognition can be imparted to the appearance of the cutting tool 1, which becomes useful commercially.

[0245] The thickness of the 3A layer 14A can be 0.1 μm or more. If the thickness of the 3A layer 14A is 0.1 μm or more, it is easy to obtain the effect of imparting lubricity based on the 3A layer 14A. On the other hand, the upper limit value of the thickness of the 3A layer 14A is not particularly limited, but if it is greater than 2 μm, there is a tendency that the effect of imparting the above lubricity cannot be further improved. Therefore, considering the cost aspect, the thickness of the 3A layer 14A can be 2 μm or less.

[0246] [Embodiment 3: Manufacturing method of cutting tool]

[0247] In Embodiment 3, the manufacturing method of the cutting tool 1 of Embodiment 1 or Embodiment 2 will be described. This manufacturing method includes a first step of preparing the base material 2 and a second step of forming the coated film 3 on the base material 2. The second step includes a step of forming the first layer 13 or the 1A layer 13A. The detailed content of each step will be described below.

[0248] <First step>

[0249] In the first step, the base material 2 is prepared. The base material 2 can use the base material 2 described in Embodiment 1.

[0250] In the case where cemented carbide is used as the substrate 2, a commercially available substrate can be used, or it can be manufactured by a general powder metallurgy method. In the case of manufacturing by a general powder metallurgy method, WC powder and Co powder are mixed by a ball mill or the like to obtain a mixed powder. After drying the mixed powder, it is formed into a predetermined shape to obtain a formed body. Further, by sintering the formed body, a WC-Co based cemented carbide (sintered body) is obtained. Then, by performing predetermined tool tip processing such as honing on the sintered body, a substrate made of WC-Co based cemented carbide can be manufactured. Even substrates other than the above can be prepared as long as they are substrates known in the past as such substrates.

[0251] <Second process>

[0252] In the second process, a coating film 3 is formed on the substrate 2. The second process includes a process of forming the first layer 13 or the 1A layer 13A.

[0253] In the "process of forming the first layer", the physical vapor deposition (PVD) method is used to form the first layer 13 by alternately laminating the first unit layer 12 and the second unit layer 15. In the "process of forming the 1A layer", the PVD method is used to form the 1A layer 13A by alternately laminating the first unit layer 12 and the third unit layer 17. In order to improve the wear resistance of the coating film 3 including the first layer 13 or the 1A layer 13A, it is effective to form a layer made of a compound with high crystallinity. The inventors of the present invention studied various methods as the formation method of the first layer 13 and the 1A layer 13A, and as a result, found that by using the physical vapor deposition method, a layer made of a compound with high crystallinity can be formed, and the coating film 3 has excellent wear resistance.

[0254] 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 (High Power Impulse Magnetron Sputtering) method can be used. In particular, the cathodic arc ion plating method with a high ionization rate of raw material elements can be used. In the case of using the cathodic arc ion plating method, before forming the first layer 13 or the 1A layer 13A, ion bombardment treatment of a metal can be performed on the surface of the substrate 2, so that the adhesion between the substrate 2 and the coating film 3 including the first layer 13 or the 1A layer 13A is significantly improved.

[0255] The cathodic arc ion plating method can be performed as follows, for example: The substrate 2 is set in the apparatus, and after setting a target as a cathode, a high voltage is applied to the target to generate arc discharge, thereby ionizing and evaporating the atoms constituting the target, and depositing the substance on the substrate 2.

[0256] The balanced magnetron sputtering method can be carried out as follows, for example: A substrate 2 is arranged in the device, and a target is arranged on a magnetron electrode equipped with a magnet that forms a balanced magnetic field. High-frequency power is applied between the magnetron electrode and the substrate 2 to generate gas plasma, and ions of the gas generated by the generation of this gas plasma are made to collide with the target, and the atoms released from the target are deposited on the substrate 2.

[0257] The unbalanced magnetron sputtering method can be carried out, for example, by making the magnetic field generated by the magnetron electrode in the above-mentioned balanced magnetron sputtering method unbalanced. Furthermore, the HiPIMS method that can apply a high voltage to obtain a dense film can also be used.

[0258] <Other processes>

[0259] On the basis of the process of forming the first layer 13 or the 1A layer 13A, the second process may further include a surface treatment process for the coating film such as grinding using a brush, dry or wet shot peening, etc. In addition, the second process may include a process of forming other layers such as the second layer 16, the 2A layer 16A, the third layer 14, the 3A layer 14A, 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 of being able to continuously form other layers with the first unit layer 12, the second unit layer 15, or the third unit layer 17 in one physical vapor deposition apparatus, the other layers are preferably formed by the physical vapor deposition method.

[0260] Examples

[0261] The present embodiment will be further specifically described by way of examples. However, the present embodiment is not limited to these examples.

[0262] [Example 1]

[0263] <Specimens 1 to 25, Specimens 101 to 106>

[0264] "Manufacture of Cutting Tools"

[0265] Figure 11 is a schematic cross-sectional view of the cathode arc ion plating apparatus used in this example, Figure 12 is Figure 11 a schematic top view of the apparatus.

[0266] In Figure 11 and Figure 12In the device, a cathode 106 for the first unit layer, which is a target made of an alloy that is a metal raw material for the coating film 3, a cathode 107 for the second unit layer, a cathode 120 for the third layer, and a rotary substrate holder 104 for setting the substrate are installed in the chamber 101. The composition of the cathode 106 is adjusted to obtain the composition of the first unit layer in Table 1. The composition of the cathode 107 is adjusted to obtain the composition of the second unit layer in Table 1. The composition of the cathode 120 is adjusted to obtain the composition of the third layer in Table 2.

[0267] An arc power source 108 is installed on the cathode 106, an arc power source 109 is installed on the cathode 107, and an arc power source (not shown) is installed on the cathode 120. In addition, a bias power source 110 is installed on the substrate holder 104. Further, a gas inlet 105 for introducing the gas 102 is provided in the chamber 101, and a gas outlet 103 is provided for adjusting the pressure in the chamber 101, and it is configured to be able to suck the gas 102 in the chamber 101 from the gas outlet 103 using a vacuum pump.

[0268] On the substrate holder 104, a carbide alloy of JIS specification P30 grade is assembled as the substrate, and a blade with a shape of CNMG120408 of JIS specification and a blade of SEMT13T3AGSN manufactured by Sumitomo Electric Carbide Co., Ltd. are used.

[0269] Next, the inside of the chamber 101 is evacuated using a vacuum pump, and while rotating the substrate, the temperature is heated to 500 °C using a heater provided in the device, and the evacuation is continued until the pressure in the chamber 101 becomes 1.0×10 -4 Pa. Next, argon is introduced from the gas inlet, the pressure in the chamber 101 is maintained at 2.0 Pa, the voltage of the bias power source 110 is gradually increased to -1000 V, and the surface of the substrate is cleaned for 15 minutes. After that, the substrate is cleaned (argon bombardment treatment) by discharging argon from the chamber 101. Through the above, the substrates of the cutting tools for each sample are prepared.

[0270] Next, while rotating the substrate in the center, while introducing argon and nitrogen as reaction gases, while maintaining the temperature of the substrate at 400 °C, maintaining the pressure of the reaction gas at 3.0 Pa, and maintaining the voltage of the bias power source 110 in the range of -50 V to -200 V at a predetermined constant value, an arc current of 100 A is supplied to the cathode 106 and the cathode 107 respectively, whereby metal ions are generated from the cathode 106 and the cathode 107, and a second layer having the composition shown in Table 2 and a first layer having the composition shown in Table 1 are formed on the substrate. Here, the purpose of introducing argon is to, for forming the first unit layer W(C 1- a Na ) x Clean the surface of the WC cathode used in the case of []. In the manufacturing method of the present disclosure, the temperature of the substrate is 400 °C, which is lower than the formation temperature of 600 °C of the nitride film in the past. The reason is as follows. The inventors of the present invention found that when the film is formed with the substrate temperature set at 600 °C, the hardness of the film tends to decrease. After studying this reason, it is speculated that when the film is formed with the substrate temperature set at 600 °C, the carbon (C) contained in the cathode for the first unit layer precipitates as free carbon in the formed film. The inventors of the present invention conducted in-depth research and found that by forming the film with the substrate temperature set at 400 °C, excellent hardness can be maintained even at high temperatures, and a film with excellent abrasion resistance can be formed.

[0271] In the case where the second layer is formed, the first layer is formed by alternately laminating the first unit layer and the second unit layer layer by layer on the second layer in the number of laminations shown in Table 1. In the case where the second layer is not formed, the first layer is formed by alternately laminating the first unit layer and the second unit layer layer by layer on the substrate in the number of laminations shown in Table 1. In addition, the thickness of the second layer, the thicknesses of the first unit layer and the second unit layer in the first layer, and the number of laminations are adjusted by the rotation speed of the substrate. Then, when the thicknesses of the second layer and the first layer reach the thicknesses shown in Table 2 and Table 1 respectively, the current supplied to the evaporation source is stopped.

[0272] Next, while introducing argon, nitrogen, and methane gas into the chamber 101 as reaction gases, while maintaining the temperature of the substrate at 400 °C, the pressure of the reaction gas at 2.0 Pa, and the voltage of the bias power supply 110 at -350 V, an arc current of 80 A is supplied to the cathode 120, thereby generating metal ions from the cathode 120 and forming a third layer on the first layer. When the thickness of the third layer reaches the thickness shown in Table 2, the current supplied to the evaporation source is stopped. The introduction amounts of nitrogen and methane gas are adjusted to obtain the composition of the third layer in Table 2. Through the above, cutting tools for each specimen were fabricated.

[0273] [Table 1]

[0274]

[0275] [Table 2]

[0276]

[0277] "Evaluation"

[0278] For the cutting tools involved in each specimen, the composition of the first unit layer, the composition of the second unit layer, the composition of the second layer, the composition of the third layer, the number of layers of the first unit layer and the second unit layer respectively, 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, the thickness of the third layer, λ2 / λ1, and the crystal structure of the first unit layer, and the hardness of the coating are measured.

[0279] <Measurement of the composition of the first unit layer>

[0280] For the cutting tools of each specimen, the composition of the first unit layer is measured by the method described in Embodiment 1, and the values of a and x in W(C 1-a N a ) x are obtained. The results are recorded in the "a" and "x" columns of Table 1. In Table 1, when "-" is recorded in the "a" column and the "x" column, it means that the first unit layer does not exist.

[0281] <Measurement of the composition of the second unit layer>

[0282] For the cutting tools of each specimen, the composition of the second unit layer is measured by the method described in Embodiment 1, and the value of c in Al c Cr 1-c N is obtained. The results are recorded in the "c" column of Table 1. In Table 1, when "-" is recorded in the "c" column, it means that the second unit layer does not exist.

[0283] <Measurement of the composition of the second layer and the third layer>

[0284] For the cutting tools of each specimen, the compositions of the second layer and the third layer are obtained by the method described in Embodiment 1. The results are recorded in the "Composition" column of "Second Layer" and the "Composition" column of "Third Layer" in Table 2. In Table 2, when "-" is recorded in the "Composition" column of "Second Layer", it means that the second layer does not exist, and when "-" is recorded in the "Composition" column of "Third Layer", it means that the third layer does not exist.

[0285] <Measurement of the number of layers>

[0286] For the cutting tools of each specimen, the number of layers of the first unit layer and the second unit layer respectively are obtained by the method described in Embodiment 1. For example, a number of layers of 10 means that the alternating layer contains 10 layers of the first unit layer and 10 layers of the second unit layer. The obtained results are respectively recorded in the "Number of Layers" column of Table 1.

[0287] <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>

[0288] For the cutting tools of each specimen, 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 are obtained by the method described in Embodiment 1. The obtained results are recorded in the columns of "Average Thickness [μm]" of "First Unit Layer", "Average Thickness [μm]" of "Second Unit Layer", "Thickness [μm]" of "First Layer" in Table 1, "Thickness [μm]" of "Second Layer" and "Thickness [μm]" of "Third Layer" in Table 2. When "-" is recorded in the column of "Thickness [μm]" of "Second Layer" in Table 2, it indicates that the second layer does not exist. When "-" is recorded in the column of "Thickness [μm]" of "Third Layer" in Table 2, it indicates that the third layer does not exist.

[0289] <Measurement of λ2 / λ1>

[0290] For the cutting tools of each specimen, λ2 / λ1 is obtained by the method described in Embodiment 1. The obtained results are recorded in the column of "λ2 / λ1" in Table 1. In addition, when "-" is recorded in the column of "λ2 / λ1" in Table 1, it indicates that at least one of the first unit layer and the second unit layer does not exist.

[0291] <Measurement of Crystal Structure of First Unit Layer>

[0292] For the cutting tools of each specimen, by performing XRD measurement on the first unit layer, it is confirmed whether the first unit layer has a hexagonal crystal structure. The specific method is as described in Embodiment 1. The results are shown in the column of "Hexagonal Crystal Structure" of "First Unit Layer" in Table 1. The record of "Yes" indicates that the first unit layer has a hexagonal crystal structure, and the record of "No" indicates that the first unit layer does not have a hexagonal crystal structure. In addition, the crystal structure of the second unit layer was measured, and as a result, it was confirmed that the second unit layer contains a cubic crystal structure in all specimens.

[0293] <Measurement of Hardness of Coating>

[0294] In Specimens 1 to 25, the hardness of the coating is measured by the method described in Embodiment 1. It is confirmed that the hardness of the coating of these specimens is in the range of 30 GPa or more and 55 GPa or less.

[0295] <Cutting Test 1: Continuous Turning Test>

[0296] For cutting tools of the CNMG120408 shape for each specimen, a dry continuous turning test was carried out under the following cutting conditions, and the time until the flank wear amount of the tool tip reached 0.2 mm was measured. The results are recorded in the column of "Cutting time [min]" in Table 2. A longer cutting time indicates a longer tool life.

[0297] 《Cutting Conditions》

[0298] · Workpiece material: SCM440 (HB = 300)

[0299] · Cutting speed: 260 m / min

[0300] · Feed rate: 0.3 mm / rev

[0301] · Depth of cut: 2.0 mm

[0302] · Coolant: Dry

[0303] The cutting operation carried out under the above cutting conditions is a high-speed and high-efficiency machining of difficult-to-cut materials, which is equivalent to the cutting operation carried out under the condition of high tool tip temperature.

[0304] The cutting tools of Specimens 1 to 25 correspond to the examples, and the cutting tools of Specimens 101 to 106 correspond to the comparative examples. It was confirmed that the cutting tools of Specimens 1 to 25 had a longer tool life in the cutting operation carried out under the condition of high tool tip temperature compared with the cutting tools of Specimens 101 to 106.

[0305] <Cutting Test 2: Milling Test>

[0306] For cutting tools of the SEMT13T3AGSN shape for each specimen, the center line of a 150-mm-wide plate made of a difficult-to-cut material was aligned with the center of a cutter wider than it, and surface milling was carried out under the following cutting conditions, and the cutting length until the flank wear amount of the tool tip reached 0.2 mm was measured. The results are recorded in the column of "Cutting length [km]" in Table 2. A longer cutting length indicates a longer tool life.

[0307] 《Cutting Conditions》

[0308] · Workpiece material: SKD11 (HB = 235)

[0309] · Cutting speed: 190 m / min

[0310] · Feed per tooth: 0.15 mm / z

[0311] · Axial depth of cut ap: 1.5 mm

[0312] ​· Radial incision ae: 150 mm

[0313] · Coolant: Dry

[0314] The cutting process performed under the above cutting conditions is a high-speed and high-efficiency milling process for difficult-to-cut materials under dry conditions, which is equivalent to a cutting process performed under conditions of high tool tip temperature.

[0315] The cutting tools of Specimens 1 to 25 are equivalent to the examples, and the cutting tools of Specimens 101 to 106 are equivalent to the comparative examples. It was confirmed that the cutting tools of Specimens 1 to 25 had a longer tool life in the cutting process performed under conditions of high tool tip temperature compared with the cutting tools of Specimens 101 to 106.

[0316] [Example 2]

[0317] <Specimens 51 to 85, Specimens 151 to 176>

[0318] 《Manufacture of Cutting Tools》

[0319] The base materials of each specimen were prepared by the same method as in Example 1. While rotating the base material in the center, argon and nitrogen were introduced as reaction gases, and while maintaining the temperature of the base material at 450 °C, the pressure of the reaction gas at 2.0 Pa, and the voltage of the bias power supply 110 at a predetermined constant value in the range of -50 V to -200 V, an arc current of 100 A was supplied to the cathodes 106 and 107, respectively, whereby metal ions were generated from the cathodes 106 and 107, and the 2A layer and the 1A layer having the compositions shown in Tables 3 to 6 were formed on the base material. The composition of the cathode 106 was adjusted to obtain the composition of the first unit layer in Tables 3 to 4. In addition, the composition of the cathode 107 was adjusted to obtain the composition of the third unit layer in Tables 3 to 4. The composition of the cathode 120 was adjusted to obtain the composition of the 3A layer in Tables 5 to 6. In the manufacturing method of the present disclosure, the temperature of the base material is 450 °C, which is lower than the formation temperature of 600 °C of the conventional nitride film. The reason is as follows. The inventors of the present invention found that when the film was formed at a base material temperature of 600 °C, the hardness of the film tended to decrease. After studying the reason, it was speculated that when the film was formed at a base material temperature of 600 °C, carbon (C) contained in the cathode for the first unit layer precipitated as free carbon in the formed film. The inventors of the present invention conducted in-depth research and found that by forming the film at a base material temperature of 450 °C, excellent hardness can be maintained even at high temperatures, and a film with excellent wear resistance can be formed.

[0320] In the case where the 2A layer is formed, the 1A layer is formed by alternately laminating the first unit layer and the third unit layer on the 2A layer layer by layer in the number of laminations shown in Tables 3 to 4. In the case where the 2A layer is not formed, the 1A layer is formed by alternately laminating the first unit layer and the third unit layer on the substrate layer by layer in the number of laminations shown in Tables 3 to 4. In addition, the thickness of the 2A layer, the thickness and the number of laminations of the first unit layer and the third unit layer in the 1A layer are adjusted by the rotation speed of the substrate. Then, when the thicknesses of the 2A layer and the 1A layer reach the thicknesses shown in Tables 3 to 6 respectively, the current supplied to the evaporation source is stopped.

[0321] Next, while introducing argon, nitrogen, and methane gas as reaction gases into the chamber 101, while maintaining the temperature of the substrate at 350 °C, the pressure of the reaction gas at 2.0 Pa, and the voltage of the bias power supply 110 at -350 V, an arc current of 100 A is supplied to the cathode 120, whereby metal ions are generated from the cathode 120, and the 3A layer is formed on the 1A layer. When the thickness of the 3A layer reaches the thicknesses shown in Tables 5 to 6, the current supplied to the evaporation source is stopped. The introduction amounts of nitrogen and methane gas are adjusted to obtain the composition of the 3A layer in Tables 5 to 6. Through the above, the cutting tools of each specimen were fabricated.

[0322] [Table 3]

[0323]

[0324] [Table 4]

[0325]

[0326] [Table 5]

[0327]

[0328] [Table 6]

[0329]

[0330] 《Evaluation》

[0331] For the cutting tools related to each specimen, the composition of the first unit layer, the composition of the third unit layer, the composition of the 2A layer, the composition of the 3A layer, the number of laminations of the first unit layer and the third unit layer respectively, the average thickness of the first unit layer, the average thickness of the third unit layer, the thickness of the 1A layer, the thickness of the 2A layer, the thickness of the 3A layer, λ3 / λ1, the crystal structure of the first unit layer, and the hardness of the coating film were measured. The measurement methods for each item are as described in Example 1. The results are shown in Tables 3 to 6.

[0332] <Measurement of the hardness of the coating film>

[0333] Among Specimens 51 to 85, the hardness of the coating was measured by the method described in Embodiment 1. It was confirmed that the hardness of the coating of these specimens was in the range of 30 GPa or more and 55 GPa or less.

[0334] <Cutting Test 3: Continuous Turning Test>

[0335] For the cutting tool of the CNMG120408 shape for each specimen, a dry continuous turning test was performed under the following cutting conditions, and the time until the flank wear amount of the tool tip reached 0.2 mm was measured. The results are shown in the "Cutting Time [minutes]" column in Tables 5 to 6. In addition, in Tables 5 to 6, a longer cutting time indicates a longer tool life.

[0336] (Cutting Conditions)

[0337] · Workpiece Material: INCONEL718 (Aged Material: HB = 400)

[0338] · Cutting Speed: 70 m / min

[0339] · Feed Rate: 0.15 mm / rev

[0340] · Depth of Cut: 1.0 mm

[0341] · Coolant: Dry

[0342] The cutting operation performed under the above cutting conditions is a high-speed and high-efficiency machining of difficult-to-cut materials, which is equivalent to the cutting operation performed under the condition of a high tool tip temperature.

[0343] The cutting tools for Specimens 51 to 85 correspond to the examples, and the cutting tools for Specimens 151 to 176 correspond to the comparative examples. It was confirmed that the cutting tools for Specimens 51 to 85 had a longer tool life in the cutting operation performed under the condition of a high tool tip temperature compared with the cutting tools for Specimens 151 to 176.

[0344] <Cutting Test 4: Milling Test>

[0345] For the cutting tool of the SEMT13T3AGSN shape for each specimen, the center line of the 150 mm-wide plate made of difficult-to-cut material was aligned with the center of the cutter wider than it , and surface milling was performed under the following cutting conditions, and the cutting length until the flank wear amount of the tool tip reached 0.2 mm was measured. The results are shown in the "Cutting Length [km]" column in Tables 5 to 6. In addition, in Tables 5 to 6, a longer cutting length indicates a longer tool life.

[0346] <Cutting Conditions>

[0347] · Workpiece material: FCD700 (HB = 250)

[0348] · Cutting speed: 260 m / min

[0349] · Feed rate: 0.2 mm / t

[0350] · Axial depth of cut ap: 2.0 mm

[0351] · Radial depth of cut ae: 150 mm

[0352] · Coolant: Dry

[0353] The cutting process performed under the above cutting conditions is a high-speed and high-efficiency milling process for a difficult-to-cut material under dry conditions, which is equivalent to a cutting process performed under conditions of a high tool tip temperature.

[0354] The cutting tools for Specimens 51 to 85 correspond to the examples, and the cutting tools for Specimens 151 to 176 correspond to the comparative examples. It was confirmed that the cutting tools for Specimens 51 to 85 have a longer tool life in the cutting process performed under conditions of a high tool tip temperature compared to the cutting tools for Specimens 151 to 176.

[0355] Although the embodiments and examples of the present disclosure have been described as above, it is also contemplated from the beginning to appropriately combine the configurations of the above-described embodiments and examples or make various modifications.

[0356] The embodiments and examples disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is represented not by the above-described embodiments and examples but by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.

[0357] Explanation of reference numerals

[0358] 1: Cutting tool; 2: Substrate; 3: Coating; 12: First unit layer; 13: First layer; 13A: First A layer; 14: Third layer; 14A: Third A layer; 15: Second unit layer; 16: Second layer; 16A: Second A layer; 17: Third unit layer; 101: Chamber; 102: Gas; 103: Gas discharge port; 104: Substrate holder; 105: Gas inlet; 106, 107, 120: 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 is composed of an alternating layer formed by alternately laminating a first unit layer and a second unit layer, the first unit layer has a hexagonal crystal structure, The first unit layer is composed of W(C 1-a N a ) x and forms where a is 0.3 or more and 0.8 or less, where x is 0.8 or more and 1.2 or less, The second unit layer is composed of Al c Cr 1-c and N. where c is 0.40 or more and 0.80 or less.

2. The cutting tool according to claim 1, wherein, in the first unit layer and the second unit layer adjacent to the first unit layer, the ratio λ2 / λ1 of the thickness λ2 μm of the second unit layer to the thickness λ1 μm of the first unit layer is 1.0 or more and 5.0 or less.

3. The cutting tool according to claim 1 or claim 2, wherein, the average thickness of the first unit layer is 0.002 μm or more and 0.2 μm or less, the average thickness of the second unit layer is 0.002 μm or more and 0.2 μm or less.

4. The cutting tool according to any one of claims 1 to 3, wherein, the coating further includes a second layer disposed between the substrate and the first layer, the composition of the second layer is the same as the composition of the first unit layer or the composition of the second unit layer.

5. The cutting tool according to claim 4, wherein, the composition of the second layer is the same as the composition of the first unit layer, the thickness of the second layer is thicker than the thickness of the first unit layer.

6. The cutting tool according to claim 4, wherein, the composition of the second layer is the same as the composition of the second unit layer, the thickness of the second layer is thicker than the thickness of the second unit layer.

7. The cutting tool according to any one of claims 1 to 6, wherein, the coating further includes a third layer disposed on the side of the first layer opposite to the substrate, the third layer is composed of AlCrCN.

8. A cutting tool comprising a substrate and a coating disposed on the substrate, wherein, the coating includes a 1A layer, the 1A layer is composed of an alternating layer formed by alternately laminating a first unit layer and a third unit layer, the first unit layer has a hexagonal crystal structure, The first unit layer is composed of W(C 1-a N a ) x and forms where a is 0.3 or more and 0.8 or less, where x is 0.8 or more and 1.2 or less, The third unit layer is composed of Al d Cr 1-d-e M e and N where M is silicon, boron, yttrium, cerium or lanthanum, where d is 0.40 or more and 0.80 or less, where e is greater than 0 and 0.05 or less.

9. The cutting tool according to claim 8, wherein, in the first unit layer and the third unit layer adjacent to the first unit layer, the ratio λ3 / λ1 of the thickness λ3 μm of the third unit layer to the thickness λ1 μm of the first unit layer is 1.0 or more and 5.0 or less.

10. The cutting tool according to claim 8 or claim 9, wherein, M is silicon.

11. The cutting tool according to claim 8 or claim 9, wherein, M is boron.

12. The cutting tool according to any one of claims 8 to 11, wherein, The average thickness of the first unit layer is 0.002 μm or more and 0.2 μm or less. The average thickness of the third unit layer is 0.002 μm or more and 0.2 μm or less.

13. The cutting tool according to any one of claims 8 to 12, wherein, the coating film further includes a second A layer disposed between the base material and the first A layer, and the composition of the second A layer is the same as the composition of the first unit layer or the composition of the third unit layer.

14. The cutting tool according to claim 13, wherein, the composition of the second A layer is the same as the composition of the first unit layer, and the thickness of the second A layer is thicker than the thickness of the first unit layer.

15. The cutting tool according to claim 13, wherein, the composition of the second A layer is the same as the composition of the third unit layer, and the thickness of the second A layer is thicker than the thickness of the third unit layer.

16. The cutting tool according to any one of claims 8 to 15, wherein, the coating film further includes a third A layer disposed on the side of the first A layer opposite to the base material, the third A layer is composed of AlCrMeCN, and Me is silicon, boron, yttrium, cerium or lanthanum.

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