Cutting Tools

Abstract

A cutting tool comprising a substrate and a coating disposed on the substrate, the coating including a first layer, the first layer being composed of alternating layers in which first unit layers and second unit layers are alternately stacked, the first unit layer being made of Ti 1-a Mo a N, the a is 0.01 or more and 0.20 or less, and the second unit layer is Al b V 1-b N, and said b is 0.40 or more and 0.80 or less.

Description

[Technical field]

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

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

[0003] [Patent Document 1] Special Publication No. 2022-512808 Summary of the Invention

[0004] The cutting tool of the present disclosure comprises: 1. A cutting tool comprising a substrate and a coating disposed on the substrate, The coating comprises a first layer, the first layer is composed of an alternating layer in which first unit layers and second unit layers are alternately laminated, The first unit layer is made of Ti 1-a Mo a It consists of N, The a is equal to or greater than 0.01 and equal to or less than 0.20, The second unit layer is made of Al b V 1-b It consists of N, The cutting tool, wherein b is equal to or greater than 0.40 and equal to or less than 0.80. [Brief description of the drawings]

[0005] [Figure 1] FIG. 1 is a schematic enlarged cross-sectional view of an example of a cutting tool according to a first embodiment. [Diagram 2] FIG. 2 is a schematic enlarged cross-sectional view of another example of the cutting tool according to the first embodiment. [Diagram 3] FIG. 3 is a schematic enlarged cross-sectional view of another example of the cutting tool according to the first embodiment. [Figure 4] FIG. 4 is a schematic enlarged cross-sectional view of another example of the cutting tool according to the first embodiment. [Diagram 5] FIG. 5 is a diagram for explaining an example of the thickness ratio between the first unit layer and the second unit layer. [Figure 6] FIG. 6 is a schematic enlarged cross-sectional view of an example of a cutting tool according to the second embodiment. [Figure 7] FIG. 7 is a schematic enlarged cross-sectional view of another example of the cutting tool according to the second embodiment. [Figure 8] FIG. 8 is a schematic enlarged cross-sectional view of another example of the cutting tool according to the second embodiment. [Figure 9] FIG. 9 is a schematic enlarged cross-sectional view of another example of the cutting tool according to the second embodiment. [Figure 10] FIG. 10 is a diagram for explaining an example of the thickness ratio between the first unit layer and the third unit layer. [Figure 11] FIG. 11 is a schematic cross-sectional view of a cathodic arc ion plating apparatus used in the examples. [Figure 12] FIG. 12 is a schematic top view of the cathodic arc ion plating apparatus shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] [Problem that this disclosure aims to solve] In recent years, efforts toward carbon neutrality have been accelerating both domestically and internationally against the backdrop of rapid global warming. In Japan, in order to achieve carbon neutrality by 2050, the manufacturing industry, especially the metal processing industry, is being asked to reduce CO2 emissions from the perspective of environmental performance in addition to the conventional quality, processing efficiency, and cost.

[0007] In the metal cutting process, the majority of electricity is consumed not in the rotation of the main shaft of the processing machine or in the feed drive during processing, but in preparation for operation, which is mainly caused by hydraulic and pneumatic units and auxiliary equipment, and in the circulation and supply of coolant (cutting oil). Therefore, efforts to save energy include not only improving the efficiency of motors and auxiliary equipment, but also adopting inverter-controlled hydraulic units and optimal operation control of hydraulic and pneumatic pressure, chip conveyors (chip transportation), etc. Furthermore, in recent years, coolant-less technology (dry processing) and semi-dry technology that atomizes coolant have been attracting attention. These technologies can reduce waste by reducing the amount of coolant, and can also save energy on the electricity required to use coolant. Therefore, progress in these technologies that contribute to energy conservation is expected.

[0008] Conventionally, research has been conducted into the application of various cutting tools and into the optimum machining conditions for each work material, and dry machining is sometimes performed on non-ferrous metals, cast iron, etc. On the other hand, although there is a high demand for dry machining of work materials that are considered difficult to cut, such as general steel and super heat-resistant alloys, dry machining is difficult even at present, and new tool materials that can handle this situation are being actively developed.

[0009] A nitride film mainly composed of aluminum (Al) and vanadium (V) has been proposed as a coating tool material (Patent Document 1). From the viewpoint of reducing CO2 and protecting the global environment, dry machining without using cutting oil is required, cutting speeds are becoming faster to improve machining efficiency, and work materials are becoming more diverse, especially in the fields of aircraft and medicine, where cutting of heat-resistant alloys and titanium alloys, which are called difficult-to-cut materials, is increasing. For these reasons, the cutting edge temperature of cutting tools during cutting tends to become high. If the cutting edge temperature becomes high, the life of the cutting tool becomes extremely short. Therefore, there is a demand for cutting tools that can exhibit excellent tool life even under such harsh cutting conditions.

[0010] [Effects of this disclosure] According to the present disclosure, it is possible to provide a cutting tool having a long tool life, particularly in cutting operations performed under conditions of high cutting edge temperatures.

[0011] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be listed and described. (1) The cutting tool of the present disclosure comprises: 1. A cutting tool comprising a substrate and a coating disposed on the substrate, The coating comprises a first layer, the first layer is composed of an alternating layer in which first unit layers and second unit layers are alternately laminated, The first unit layer is made of Ti 1-a Mo a It consists of N, The a is equal to or greater than 0.01 and equal to or less than 0.20, The second unit layer is made of Al b V 1-b It consists of N, The cutting tool, wherein b is equal to or greater than 0.40 and equal to or less than 0.80.

[0012] According to the present disclosure, it is possible to provide a cutting tool having a long tool life, particularly in cutting operations performed under conditions of high cutting edge temperatures.

[0013] (2) In the above (1), the ratio λ2 / λ1 of the thickness λ2 μm of the second unit layer to the thickness λ1 μm of the first unit layer in the first unit layer and the second unit layer adjacent to the first unit layer may be 1.0 or more and 5.0 or less, thereby enabling the cutting tool to have a longer tool life.

[0014] (3) In (1) or (2) above, The average thickness of the first unit layer is 0.002 μm or more and 0.2 μm or less, The second unit layer may have an average thickness of 0.002 μm or more and 0.2 μm or less. This allows the cutting tool to have a longer tool life.

[0015] (4) In any of (1) to (3) above, The coating further includes a surface layer provided on a side of the first layer opposite the substrate, The surface layer may consist of TiMoON or AlVON. This allows the cutting tool to have a longer tool life.

[0016] (5) The cutting tool of the present disclosure is 1. A cutting tool comprising a substrate and a coating disposed on the substrate, the coating comprises a second layer; the second layer is composed of alternating layers in which first unit layers and third unit layers are alternately laminated, The first unit layer is made of Ti 1-a Mo a It consists of N, The a is equal to or greater than 0.01 and equal to or less than 0.20, The third unit layer is made of Al c V 1-c-d X d It consists of N, X is one or two selected from the group consisting of boron, silicon, scandium, yttrium, and cerium, The c is equal to or greater than 0.40 and equal to or less than 0.80, The cutting tool, wherein d is equal to or greater than 0.001 and equal to or less than 0.05.

[0017] According to the present disclosure, it is possible to provide a cutting tool having a long tool life, particularly in cutting operations performed under conditions of high cutting edge temperatures.

[0018] (6) In the above (5), the ratio λ3 / λ1 of the thickness λ3 μm of the third unit layer to the thickness λ1 μm of the first unit layer in the first unit layer and the third unit layer adjacent to the first unit layer may be 1.0 or more and 5.0 or less, thereby enabling the cutting tool to have a longer tool life.

[0019] (7) In (5) or (6) above, The average thickness of the first unit layer is 0.002 μm or more and 0.2 μm or less, The third unit layer may have an average thickness of 0.002 μm or more and 0.2 μm or less. This allows the cutting tool to have a longer tool life.

[0020] (8) In any of (5) to (7) above, The coating further includes a surface layer provided on the second layer opposite the substrate, The surface layer is made of TiMoON or AlVXON, The X may be one or two elements selected from the group consisting of boron, silicon, scandium, yttrium, and cerium. This allows the cutting tool to have a longer tool life.

[0021] [Details of the embodiment of the present disclosure] Specific examples of the cutting tool of the present disclosure will be described below with reference to the drawings. In the drawings of the present disclosure, the same reference numerals represent the same or corresponding parts. Furthermore, dimensional relationships such as length, width, thickness, and depth have been appropriately changed for clarity and simplification of the drawings, and do not necessarily represent actual dimensional relationships.

[0022] In the present disclosure, an expression in the form "A~B" means greater than or equal to A and less than or equal to B. When no unit is specified for A and a unit is specified only for B, the unit of A and the unit of B are the same.

[0023] In the present disclosure, when a compound or the like is represented by a chemical formula, unless the atomic ratio is particularly limited, it is intended to include any conventionally known atomic ratio, and should not necessarily be limited to only those within the stoichiometric range.

[0024] In the present disclosure, when one or more numerical values ​​are listed as the lower limit and the upper limit of a numerical range, the combination of any one numerical value listed in the lower limit and any one numerical value listed in the upper limit is also disclosed.

[0025] [Embodiment 1: Cutting tool (1)] A cutting tool according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 5. FIG. A cutting tool 1 according to one embodiment of the present disclosure (hereinafter also referred to as "embodiment 1") includes: A cutting tool 1 comprising a substrate 2 and a coating 3 disposed on the substrate 2, The coating 3 includes a first layer 13, The first layer 13 is composed of alternating layers in which first unit layers 12 and second unit layers 15 are alternately laminated, The first unit layer 12 is made of Ti 1-a Mo a It consists of N, a is equal to or greater than 0.01 and equal to or less than 0.20, The second unit layer 15 is made of Al b V 1-b It consists of N, b is greater than or equal to 0.40 and less than or equal to 0.80, for cutting tool 1.

[0026] The cutting tool of the first embodiment has a long tool life, especially in cutting operations performed under conditions of high cutting edge temperatures, and the reason for this is believed to be as follows.

[0027] The first unit layer is Ti 1-a Mo a The first unit layer is made of N. Since the first unit layer contains Mo (molybdenum), it is oxidized during cutting to produce MoO3, an oxide of Mo. Since the melting point of MoO3 is 795°C, it softens at the temperature during cutting and functions as a lubricant, reducing the coefficient of friction on the tool rake face. As a result, the first layer including the first unit layer can improve adhesion resistance, sliding properties, and wear resistance in processes where the cutting edge becomes hot, such as dry cutting processes.

[0028] The second unit layer is Al b V 1-bThe second unit layer is made of N. The second unit layer contains Al. Since Al is easily oxidized, a coating containing the second unit layer tends to have a dense oxide layer made of Al2O3 formed on the surface side of the first layer. As a result, the thermal barrier properties and oxidation resistance of the first layer can be improved.

[0029] The second unit layer is oxidized during cutting to produce V2O5, an oxide of V. Since the melting point of V2O5 is 690°C, it softens at the temperature during cutting and functions as a lubricant, reducing the coefficient of friction on the tool rake face.

[0030] The first layer is composed of alternating layers in which first unit layers and second unit layers are alternately laminated. The composition and crystal lattice are discontinuous at the interface between the first unit layer and the second unit layer. Therefore, if a crack occurs on the surface of the coating during cutting, the crack can be prevented from progressing at the interface. In a coating including the first layer, chipping and damage are prevented.

[0031] As described above, a cutting tool including a first layer made up of alternating layers in which first unit layers and second unit layers are alternately laminated has an improved tool life.

[0032] <Cutting tools> As shown in Fig. 1 and Fig. 2, a cutting tool 1 according to an embodiment of the present invention includes a substrate 2 and a coating 3 disposed on the substrate 2. The coating 3 can cover at least a portion of the substrate 2 involved in cutting. The coating 3 may cover the entire surface of the substrate 2. Even if the configuration of the coating 3 is partially different, it does not deviate from the scope of this embodiment. In the present disclosure, the portion of the substrate 2 involved in cutting refers to an area on the surface of the substrate 2 that is at least within 50 µm, 100 µm, or 300 µm away from the cutting edge.

[0033] The cutting tool of embodiment 1 can be suitably used as cutting tools such as drills, end mills, indexable cutting tips for drills, indexable cutting tips for end mills, indexable cutting tips for milling, indexable cutting tips for turning, metal saws, gear cutting tools, reamers, and taps.

[0034] <Base material> Any known substrate can be used. For example, the substrate may be made of any of cemented carbide (WC-based cemented carbide, cemented carbide containing WC and Co, cemented carbide containing carbonitrides such as Ti, Ta, Nb, etc. added to WC and Co), cermet (mainly composed of TiC, TiN, TiCN, etc.), high-speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, etc.), cubic boron nitride sintered body, and diamond sintered body.

[0035] The substrate may be, in particular, a WC-based cemented carbide or cermet (particularly, a TiCN-based cermet). The WC-based cemented carbide or cermet has an excellent balance between hardness and strength, particularly at high temperatures, and therefore, when used as a substrate for a cutting tool, can contribute to extending the life of the cutting tool.

[0036] <Coating> In the cutting tool of embodiment 1, the coating includes a first layer. The coating covers the substrate, thereby improving various properties of the cutting tool, such as wear resistance and chipping resistance, and has the effect of extending the life of the cutting tool.

[0037] The coating may include other layers in addition to the first layer, such as a base layer 16 disposed between the substrate 2 and the first layer 13, and a surface layer 14 provided on the side of the first layer 13 opposite the substrate 2, as shown in Fig. 3 and Fig. 4.

[0038] The coating may have a total thickness of 0.4 μm or more and 15 μm or less. If the total thickness of the coating is 0.4 μm or more, the effect of extending the life of the cutting tool by providing the coating is easily obtained. On the other hand, if the total thickness of the coating is 15 μm or less, chipping of the coating is unlikely to occur in the early stages of cutting, and the life of the cutting tool can be extended.

[0039] The total thickness of the coating can be measured by observing the cross section of the coating using a scanning electron microscope (SEM). A cutting tool is cut in a direction along the normal to the surface of the coating to prepare a cross section sample. The cross section sample is observed with the SEM. The observation magnification is 5000 to 10000 times, and the measurement field of view is 100 to 500 μm. 2 The thickness width is measured at three points in one visual field, and the average value of the thickness widths at the three points is calculated. This average value corresponds to the overall thickness of the coating. The thickness of each layer described below is also measured in the same manner unless otherwise specified.

[0040] The absolute value of the compressive residual stress of the coating may be 6 GPa or less. The compressive residual stress of the coating is a type of internal stress (intrinsic strain) that exists throughout the coating, and is a stress expressed as a "-" (negative) numerical value (unit: "GPa" is used in this embodiment). Therefore, the concept of a large compressive residual stress refers to a large absolute value of the numerical value, and the concept of a small compressive residual stress refers to a small absolute value of the numerical value. In other words, the absolute value of the compressive residual stress being 6 GPa or less means that the compressive residual stress of the coating 3 is -6 GPa or more and 0 GPa or less.

[0041] When the compressive residual stress of the coating is 0 GPa or less, it is easy to suppress the growth of cracks that initiate from the outermost surface of the coating. On the other hand, when 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 peeling of the coating from the edge of the cutting tool before cutting begins.

[0042] The compressive residual stress of the coating was measured using an X-ray residual stress device. 2It is measured by the ψ method (see pages 54-66 of "X-Ray Stress Measurement Method" (published by Yokendo Co., Ltd., 1981, by the Japan Society for Materials Science)).

[0043] The hardness of the coating is highly effective when it is 30 GPa or more and 55 GPa or less, and may be 35 GPa or more and 50 GPa or less. This means that the coating has sufficient hardness. The hardness of the entire coating is measured by a nanoindenter method (Nano Indenter XP manufactured by MTS Corporation). Specifically, the method is performed in accordance with ISO14577, the measurement load is 10 mN (1 gf), the hardness is measured at three points on the surface of the coating 3, and the average value of the hardness at the three points is calculated. The average value corresponds to the hardness of the coating 3.

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

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

[0046] The thickness of the first layer 13 may be 0.5 μm or more and 15 μm or less, 2 μm or more and 15 μm or less, or 5 μm or more and 10 μm or less. When the thickness of the first layer 13 is 0.5 μm or more, excellent wear resistance can be exhibited in continuous processing. When the thickness of the first layer 13 is 15 μm or less, excellent chipping resistance can be exhibited in interrupted cutting.

[0047] The thickness of the first layer can be measured by observing the cross section of the coating using a transmission electron microscope (TEM). A cutting tool is used to cut the coating in a direction normal to the surface, to prepare a thin section sample including the cross section. The thin section sample is observed with 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 width of the first layer is measured at three points in one visual field, and the average value of the thickness widths at the three points is calculated. The average value corresponds to the thickness of the first layer.

[0048] The first unit layer can have a cubic crystal structure. When the first unit layer has a cubic crystal structure, the abrasion resistance of the coating is improved. The second unit layer can include a cubic crystal structure. When the second unit layer has a cubic crystal structure, the hardness of the coating is improved. The crystal structure of each layer in the coating can be analyzed by an X-ray diffraction device known in the art.

[0049] The X-ray diffraction measurement can be performed using a device such as "SmartLab" (product name) manufactured by Rigaku Corp. The conditions for the X-ray diffraction measurement are as follows. (XRD measurement conditions) Scanning axis: 2θ-θ X-ray source: Cu-Kα ray (1.541862Å) Detector: 0-dimensional detector (scintillation counter) Tube voltage: 45kV Tube current: 40mA Incident optical system: Use of mirrors Receiving optical system: Use of analyzer crystal (PW3098 / 27) Step: 0.03° Accumulation time: 2 seconds Scan range (2θ): 10°~120°

[0050] <Composition of the first unit layer and composition of the second unit layer> The first unit layer is Ti 1-a Mo aN, and a is 0.01 or more and 0.20 or less. a may be 0.03 or more and 0.18 or less, 0.05 or more and 0.15 or less, or 0.08 or more and 0.14 or less.

[0051] In the present disclosure, "the first unit layer is Ti 1-a Mo a The term "comprised of TiN" means that the first unit layer is made of TiN as long as it does not impair the effect of the present disclosure. 1-a Mo a This means that inevitable impurities can be contained in addition to N. Examples of inevitable impurities include oxygen and carbon. The total content of inevitable impurities in the first unit layer may be greater than 0 atomic % and less than 1 atomic %.

[0052] The second unit layer is Al b V 1-b N, and b is 0.40 or more and 0.80 or less. b may be 0.45 or more and 0.75 or less, 0.50 or more and 0.70 or less, or 0.55 or more and 0.65 or less.

[0053] In the present disclosure, "the second unit layer is Al b V 1-b The term "made of AlN" means that the second unit layer 15 is made of AlN as long as it does not impair the effect of the present disclosure. b V 1-b This means that inevitable impurities can be contained in addition to N. Examples of inevitable impurities include oxygen and carbon. The total content of inevitable impurities in the second unit layer may be more than 0 atomic % and less than 1 atomic %.

[0054] The above a, the above b, and the content of inevitable impurities in the first unit layer and the content of inevitable impurities in the second unit layer are measured by elemental analysis of the cross section of the coating using a transmission electron microscope (TEM). A cutting tool is cut in a direction along the normal line of the surface of the coating to prepare a thin sample including the cross section of the coating. vUsing an electron beam X-ray spectroscopy (E X-ray spectroscopy), an electron beam is irradiated onto a thin sample, and the energy and number of characteristic X-rays generated at that time are measured to perform elemental analysis of the first and second unit layers. Five layers each of the first and second unit layers are arbitrarily selected, and elemental analysis is performed. The average composition of the five first unit layers is determined. This average composition corresponds to the composition of the first unit layer. The average composition of the five second unit layers is determined. This average composition corresponds to the composition of the second unit layer. When the number of layers of each of the first and second unit layers is four or less, elemental analysis is performed on all layers to determine the average composition of the first and second unit layers. It has been confirmed that there is no variation in the measurement results even if the measurement points are arbitrarily selected as long as the same cutting tool is used for the measurement.

[0055] In the present disclosure, the composition of the first unit layer is Ti 1-a Mo a In N, the total number of Ti and Mo atoms is A M1 Number of N atoms A N1 Ratio of A N1 / A M1 In the present disclosure, the composition Al of the second unit layer is 0.8 or more and 1.2 or less. b V 1-b In N, the total number of Al and V atoms is A M2 Number of N atoms A N2 Ratio of A N2 / A M2 is 0.8 or more and 1.2 or less. N1 / A M1 and ratio A N2 / A M2 can be measured by the Rutherford backscattering (RBS) method. N1 / A M1 and ratio A N2 / A M2 It has been confirmed that the effect of the present disclosure is not impaired if the amount is within the above range.

[0056] <Average thickness of first unit layer and average thickness of second unit layer> The average thickness of the first unit layer may be 0.002 μm or more and 0.2 μm or less, and the average thickness of the second unit layer may be 0.002 μm or more and 0.2 μm or less. This can further suppress the progression of cracks that occur on the surface of the coating. The average thickness of the first unit layer may be 0.005 μm or more and 0.15 μm or less, or 0.01 μm or more and 0.1 μm or less. The average thickness of the second unit layer may be 0.005 μm or more and 0.15 μm or less, or 0.01 μm or more and 0.10 μm or less.

[0057] The average thickness of the first unit layer and the average thickness of the second unit layer are measured by the same method as the method for measuring the thickness of the first layer.

[0058] As shown in FIG. 5, in the first unit layer 12 and the second unit layer 15 adjacent to the first unit layer 12, the ratio λ2 / λ1 of the thickness λ2μm of the second unit layer 15 to the thickness λ1μm of the first unit layer 12 may be 1.0 or more and 5.0 or less. In addition to having high oxidation resistance, the second unit layer has a low thermal conductivity and is difficult to transmit heat generated during cutting to the base material. When the ratio λ2 / λ1 is 1.0 or more, the proportion of the second unit layer in the coating increases relatively, and the amount of Al in the coating increases, improving the heat barrier properties of the cutting tool as a whole, and especially improving the wear resistance during continuous cutting. When λ2 / λ1 is 1.0 or more, the toughness of the coating tends to improve. On the other hand, when λ2 / λ1 is 5.0 or less, the effect of suppressing the progress of cracks by laminating the first unit layer 12 and the second unit layer 15 tends to be easily obtained.

[0059] λ2 / λ1 may be 1.1 or more and 5.0 or less, 1.2 or more and 5.0 or less, 1.3 or more and 4.0 or less, 1.8 or more and 3.0 or less, or 2.0 or more and 2.5 or less.

[0060] For the sake of explanation in Figure 5, the thicknesses of all three first unit layers 12 are shown as λ1, and the thicknesses of all three second unit layers 15 are shown as λ2. However, as long as the above-mentioned λ2 / λ1 relationship is satisfied between adjacent first unit layers and second unit layers, the thicknesses λ1 of the three first unit layers 12 do not need to be the same, and the thicknesses λ2 of the three second unit layers 15 do not need to be the same.

[0061] In the first layer, the number of stacked first unit layers and second unit layers may be 5 or more and 500 or less, 10 or more and 500 or less, 100 or more and 400 or less, or 200 or more and 350 or less. According to this, by stacking the first unit layers and the second unit layers, it is possible to sufficiently obtain the effect of improving hardness and compressive residual stress in a well-balanced manner.

[0062] In the first layer, the number of first unit layers and second unit layers can be determined by observing a thin sample of the cross section of the coating using a TEM (transmission electron microscope) at a magnification of 20,000 to 5,000,000 times.

[0063] <Underlayer> 3 and 4, the coating 3 may further include an underlayer 16 disposed between the substrate 2 and the first layer 13. The composition of the underlayer 16 may be the same as the composition of the first unit layer 12 or the composition of the second unit layer 15. This can increase the adhesion between the substrate 2 and the coating 3.

[0064] When the composition of the underlayer is the same as that of the first unit layer, even if the underlayer is exposed at the beginning of cutting, the underlayer has good sliding properties and therefore the wear resistance can be improved.

[0065] When the composition of the underlayer is the same as that of the first unit layer, the thickness of the underlayer may be greater than that of the first unit layer. This can further increase the adhesion between the substrate and the coating. The thickness of the underlayer may be more than 1.0 times and less than 500 times, 2.0 times or more and less than 500 times, 4.0 times or more and less than 120 times, or 10.0 times or more and less than 50 times the thickness of the first unit layer.

[0066] When the composition of the underlayer is the same as that of the first unit layer, the thickness of the underlayer may be 0.1 μm to 2 μm, 0.3 μm to 2 μm, or 0.4 μm to 2 μm. If the thickness of the underlayer is less than 0.1 μm, it tends to be difficult to obtain the effect of improving the wear resistance by making the underlayer have the same composition as the first unit layer. If the thickness of the underlayer exceeds 2 μm, the crystal grains are enlarged and grain boundaries are generated, so that it tends to be difficult to obtain the effect of improving the wear resistance.

[0067] When the composition of the underlayer is the same as the composition of the first unit layer, the first unit layer 12 may be laminated directly on the underlayer 16, as shown in Fig. 3. Also, the second unit layer 15 may be laminated directly on the underlayer 16, as shown in Fig. 4. When the composition of the underlayer 16 is the same as the composition of the first unit layer 12 and the first unit layer 12 is laminated directly on the underlayer 16, the underlayer 16 and the first unit layer 12 have a continuous crystal structure.

[0068] When the composition of the underlayer is the same as the composition of the second unit layer, even if the underlayer is exposed at the beginning of cutting, oxidation from the interface between the substrate and the coating can be suppressed and cutting heat can be insulated.

[0069] When the composition of the underlayer is the same as that of the second unit layer, the thickness of the underlayer may be thicker than that of the second unit layer. This can further increase the adhesion between the substrate and the coating. The thickness of the underlayer may be more than 1.0 times and not more than 500 times, 2.0 times or more and not more than 500 times, 4.0 times or more and not more than 120 times, or 10.0 times or more and not more than 50 times the thickness of the second unit layer.

[0070] When the composition of the underlayer is the same as that of the second unit layer, the thickness of the underlayer may be 0.1 μm or more and 2 μm or less, 0.3 μm or more and 2 μm or less, or 0.4 μm or more and 2 μm or less.

[0071] When the composition of the underlayer is the same as the composition of the second unit layer, the first unit layer 12 may be laminated directly on the underlayer 16, as shown in Fig. 3. Also, the second unit layer 15 may be laminated directly on the underlayer 16, as shown in Fig. 4. When the composition of the underlayer 16 is the same as the composition of the second unit layer 15 and the second unit layer 15 is laminated directly on the underlayer 16, the underlayer 16 and the second unit layer 15 have a continuous crystal structure.

[0072] <Surface layer> 1 to 4, the coating 3 may further include a surface layer 14 provided on the side of the first layer 13 opposite the substrate 2. The surface layer 14 may be made of TiMoON or AlVON, which can reduce the friction coefficient of the coating and extend the life of the cutting tool.

[0073] In general, oxynitrides tend to have higher adhesion resistance to work materials than nitrides. The improvement in adhesion resistance is thought to be due to the contribution of oxygen atoms. When a coating includes a surface layer made of oxynitride, the adhesion resistance of the coating to the work material is improved, and the life of the cutting tool is extended.

[0074] It is possible to impart a desired color to the surface layer by adjusting the composition ratio of O and N. This makes it possible to impart design and distinctiveness to the appearance of cutting tools, making them commercially useful.

[0075] The thickness of the surface layer 14 may be 0.1 μm or more and 2 μm or less. When the thickness of the surface layer 14 is 0.1 μm or more, the lubricity imparting effect of the surface layer 14 is easily obtained. When the thickness of the surface layer exceeds 2 μm, the above-mentioned lubricity imparting effect tends not to be further improved. Therefore, in consideration of the cost, the thickness of the surface layer may be 2 μm or less.

[0076] <Middle Class> In the cutting tool of the first embodiment, the coating may include an intermediate layer disposed between the base layer and the first layer. Examples of the intermediate layer include TiMoN, AlVCeN, AlVN, AlVBN, AlVSiN, AlVYN, and AlVScN. The thickness of the intermediate layer may be 0.1 μm or more and 2 μm or less, 0.3 μm or more and 1.5 μm or less, or 0.4 μm or more and 1.0 μm or less.

[0077] [Embodiment 2: Cutting tool (2)] A cutting tool according to another embodiment of the present disclosure will be described with reference to FIGS. A cutting tool 1 according to another embodiment of the present disclosure (hereinafter also referred to as “embodiment 2”) includes: A cutting tool 1 comprising a substrate 2 and a coating 3 disposed on the substrate 2, The coating 3 includes a second layer 13A, The second layer 13A is composed of alternating layers in which the first unit layers 12 and the third unit layers 17 are alternately laminated, The first unit layer 12 is made of Ti 1-a Mo a It consists of N, a is equal to or greater than 0.01 and equal to or less than 0.20, The third unit layer 17 is made of Al c V 1-c-d X d It consists of N, X is one or two selected from the group consisting of boron, silicon, scandium, yttrium, and cerium; c is equal to or greater than 0.40 and equal to or less than 0.80; The cutting tool 1 has a diameter d which is equal to or greater than 0.001 and equal to or less than 0.05.

[0078] The cutting tool of the second embodiment has a long tool life, especially in cutting operations performed under conditions of high cutting edge temperatures, and the reason for this is believed to be as follows.

[0079] The first unit layer is Ti 1-a Mo aN. Therefore, for the same reasons as those described in the first embodiment, the first layer including the first unit layer can improve adhesion resistance, sliding properties, and wear resistance in processing in which the cutting edge becomes hot, such as during dry cutting processing.

[0080] The third unit layer is Al c V 1-c-d X d The third unit layer is made of N. The third unit layer contains Al. Since Al is easily oxidized, a coating containing the third unit layer tends to have a dense oxide layer made of Al2O3 formed on the surface side of the second layer. As a result, the thermal barrier properties and oxidation resistance of the second layer can be improved.

[0081] The third unit layer is oxidized during cutting to produce V2O5, an oxide of V. Since the melting point of V2O5 is 690°C, it softens at the temperature during cutting and functions as a lubricant, reducing the coefficient of friction on the tool rake face.

[0082] The second layer is composed of alternating layers in which the first unit layers and the third unit layers are alternately laminated. The composition and crystal lattice are discontinuous at the interface between the first unit layers and the third unit layers. Therefore, if a crack occurs on the surface of the coating during cutting, the crack can be prevented from progressing at the interface. In the coating including the second layer, chipping and damage are prevented.

[0083] The cutting tool of the second embodiment can have basically the same configuration as the cutting tool of the first embodiment, except for the configurations of the second layer, the base layer, and the surface layer. The "second layer", "base layer", and "surface layer" will be described below.

[0084] <Second layer> In the cutting tool of the second embodiment, the second layer is made of alternating layers in which the first unit layers and the third unit layers are alternately stacked. The fact that the second layer is made of alternating layers in which the first unit layers and the third unit layers are alternately stacked can be confirmed by observing the cross section of the coating with a TEM and observing the difference in contrast. The thickness of the second layer can be the same as the thickness of the first layer described in the first embodiment. Either the first unit layer or the third unit layer may be disposed in a position closest to the substrate side. The first unit layer can have a cubic crystal structure. The third unit layer can include a cubic crystal structure.

[0085] <Composition of the first unit layer and composition of the third unit layer> Composition Ti of the first unit layer of embodiment 2 1-a Mo a N is the composition Ti of the first unit layer of embodiment 1. 1-a Mo a It can be the same as N.

[0086] The third unit layer is Al c V 1-c-d X d N, X is one or two elements selected from the group consisting of boron, silicon, scandium, yttrium, and cerium, c is 0.40 or more and 0.80 or less, and d is 0.001 or more and 0.05 or less. The third unit layer 17 can have both excellent hardness and excellent oxidation resistance. The reason for this is presumed to be as follows.

[0087] Third unit layer Al c V 1-c-d X d In the case where X in N is boron, the boron increases the hardness of the third unit layer, and the hardness of the entire coating increases. In addition, the boron oxide formed by the oxidation of the surface of the cutting tool during cutting densifies the aluminum oxide in the third unit layer, improving the oxidation resistance of the third unit layer. Furthermore, since the boron oxide has a low melting point, it acts as a lubricant during cutting and can suppress adhesion of the work material.

[0088] Third unit layer Al c V 1-c-d Xd In the case where X in N is silicon, the structure of the third unit layer becomes finer, and as a result, the hardness and oxidation resistance of the third unit layer are improved, and the hardness and oxidation resistance of the entire coating are improved.

[0089] Third unit layer Al c V 1-c-d X d In N, when X is one or two elements selected from the group consisting of scandium (Sc), yttrium (Y) and cerium (Ce), the elements precipitate at the grain boundaries of the third unit layer, and the oxides of these elements can suppress the inward diffusion of oxygen from the coating surface through the grain boundaries, thereby improving the oxidation resistance of the third unit layer and lengthening the life of a cutting tool including the third unit layer.

[0090] The above-mentioned c is 0.40 or more and 0.80 or less. This makes the crystal structure of the third unit layer a cubic type, and the third unit layer has high hardness and improves wear resistance. c may be 0.45 or more and 0.75 or less, 0.50 or more and 0.70 or less, or 0.55 or more and 0.65 or less.

[0091] The above d is 0.001 or more and 0.05 or less. This can improve the hardness and oxidation resistance of the second layer. d may be 0.01 or more and 0.05 or less, 0.02 or more and 0.05 or less, 0.02 or more and 0.04 or less, or 0.02 or more and 0.03 or less.

[0092] In the present disclosure, "the third unit layer is Al c V 1-c-d X d The term "consisting of AlN" means that the third unit layer is made of AlN, as long as it does not impair the effect of the present disclosure. c V 1-c-d X d This means that inevitable impurities can be contained in addition to N. Examples of the inevitable impurities include oxygen and carbon. The total content of the inevitable impurities in the third unit layer may be more than 0 atomic % and less than 1 atomic %.

[0093] The contents of the inevitable impurities of the above c, d and the third unit layer are measured using a transmission electron microscope (TEM). The specific measurement method is the same as the measurement method of the above a described in embodiment 1. It has been confirmed that there is no variation in the measurement results even if the measurement points are arbitrarily selected as long as the measurement is performed using the same cutting tool.

[0094] In the present disclosure, the composition of the first unit layer is Ti 1-a Mo a In N, the total number of Ti and Mo atoms is A M1 Number of N atoms A N1 Ratio of A N1 / A M1 In the present disclosure, the composition Al of the third unit layer is 0.8 or more and 1.2 or less. c V 1-c-d X d In N, the total number of Al, V and X atoms is A M3 Number of N atoms A N3 Ratio of A N3 / A M3 is 0.8 or more and 1.2 or less. N3 / A M3 can be measured by the Rutherford backscattering (RBS) method. N1 / A M1 and ratio A N3 / A M3 It has been confirmed that the effect of the present disclosure is not impaired if the amount is within the above range.

[0095] <Average thickness of first unit layer and average thickness of third unit layer> The average thickness of the first unit layer may be 0.002 μm or more and 0.2 μm or less, and the average thickness of the third unit layer may be 0.002 μm or more and 0.2 μm or less. This can further suppress the progression of cracks that occur on the surface of the coating. The average thickness of the first unit layer may be 0.005 μm or more and 0.15 μm or less, or 0.01 μm or more and 0.1 μm or less. The average thickness of the third unit layer may be 0.005 μm or more and 0.15 μm or less, or 0.01 μm or more and 0.10 μm or less.

[0096] The average thickness of the first unit layer and the average thickness of the third unit layer can be determined by the same method as the method for measuring the thickness of the first layer described in the first embodiment.

[0097] As shown in FIG. 10, 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 λ3μm of the third unit layer 17 to the thickness λ1μm of the first unit layer 12 may be 1.0 or more and 5.0 or less. The third unit layer has high oxidation resistance, and has low thermal conductivity and is difficult to transmit heat generated during cutting to the base material. When the ratio λ3 / λ1 is 1.0 or more, the proportion of the third unit layer in the coating increases relatively, and the amount of Al in the coating increases, improving the heat barrier of the cutting tool as a whole, and especially improving the wear resistance during continuous cutting. When λ3 / λ1 is 1.0 or more, the toughness of the coating tends to improve. On the other hand, when λ3 / λ1 is 5.0 or less, the effect of suppressing the progress of cracks by laminating the first unit layer and the third unit layer tends to be easily obtained.

[0098] λ3 / λ1 may be 1.1 or more and 5.0 or less, 1.2 or more and 5.0 or less, 1.3 or more and 4.0 or less, 1.8 or more and 3.0 or less, or 2.0 or more and 2.5 or less.

[0099] For the sake of explanation in Figure 10, the thicknesses of all three first unit layers 12 are shown as λ1, and the thicknesses of all three third unit layers 17 are shown as λ3. However, as long as the above-mentioned λ3 / λ1 relationship is satisfied between adjacent first unit layers and third unit layers, the thicknesses λ1 of the three first unit layers 12 do not need to be the same, and the thicknesses λ3 of the three third unit layers 17 do not need to be the same.

[0100] In the second layer, the number of laminations of each of the first unit layers and the third unit layers may be 4 or more and 800 or less, 10 or more and 500 or less, 100 or more and 400 or less, or 200 or more and 350 or less. According to this, by laminating the first unit layers and the third unit layers, the effect of improving the hardness and the compressive residual stress in a well-balanced manner can be sufficiently obtained.

[0101] In the second layer, the number of stacked first unit layers and the number of stacked third unit layers can be determined by the same method as the method for measuring the number of stacked first unit layers and the number of stacked second unit layers described in the first embodiment.

[0102] <Underlayer> 8 and 9, the coating 3 further includes an underlayer 16 disposed between the substrate 2 and the second layer 13A, and the composition of the underlayer 16 may be the same as the composition of the first unit layer 12 or the composition of the third unit layer 17. This can improve the adhesion between the substrate 2 and the coating 3.

[0103] When the composition of the underlayer is the same as that of the first unit layer, the effect and the thickness of the underlayer are as described in the first embodiment.

[0104] When the composition of the base layer 16 is the same as the composition of the third unit layer 17, the third unit layer tends to have a smaller stress, and therefore the peeling resistance of the coating can be improved, particularly in intermittent machining such as milling and end milling in which loads are repeatedly applied to the cutting edge.

[0105] When the composition of the underlayer is the same as that of the third unit layer, the thickness of the underlayer may be thicker than that of the third unit layer. This can further increase the adhesion between the substrate and the coating. The thickness of the underlayer may be more than 1.0 times and not more than 500 times, 2.0 times or more and not more than 500 times, 4.0 times or more and not more than 120 times, or 10.0 times or more and not more than 50 times the thickness of the third unit layer.

[0106] When the composition of the underlayer is the same as that of the third unit layer, the thickness of the underlayer may be 0.1 μm or more and 2 μm or less, 0.3 μm or more and 2 μm or less, or 0.4 μm or more and 2 μm or less.

[0107] When the composition of the underlayer is the same as the composition of the third unit layer, the first unit layer may be laminated directly on the underlayer, as shown in Fig. 8. Also, the third unit layer may be laminated directly on the underlayer, as shown in Fig. 9. When the composition of the underlayer is the same as the composition of the third unit layer and the third unit layer is laminated directly on the underlayer, the underlayer and the third unit layer have a continuous crystal structure.

[0108] <Surface layer> As shown in Figs. 6 to 9, the coating 3 may further include a surface layer 14 provided on the side of the second layer 13A opposite to the substrate 2. The surface layer 14 may be made of TiMoON or AlVXON. Here, X may be one or two elements selected from the group consisting of boron, silicon, scandium, yttrium, and cerium. X may be the same element as X used in the third unit layer. This can reduce the friction coefficient of the coating and extend the life of the cutting tool.

[0109] It is possible to impart a desired color to the surface layer by adjusting the composition ratio of O and N. This makes it possible to impart design and distinctiveness to the appearance of cutting tools, making them commercially useful.

[0110] The thickness of the surface layer 14 may be as described in the first embodiment.

[0111] [Embodiment 3: Manufacturing method of cutting tool] In the third embodiment, a method for manufacturing the cutting tool of the first or second embodiment will be described. The method for manufacturing the cutting tool of the third embodiment includes a first step of preparing a substrate and a second step of forming a coating on the substrate. The second step includes a step of forming a first layer or a second layer. Details of each step will be described below.

[0112] <1st process> In the first step, a substrate is prepared. The substrate may be the substrate described in embodiment 1. Any substrate known in the art may be prepared.

[0113] <Second process> In the second step, a coating is formed on the substrate. The second step includes forming the first layer or the second layer.

[0114] In the step of forming the first layer, the first unit layer and the second unit layer are alternately laminated using a physical vapor deposition (PVD) method to form the first layer. In the step of forming the second layer, the first unit layer and the third unit layer are alternately laminated using a PVD method to form the second layer. In order to improve the abrasion resistance of a coating including the first layer or the second layer, it is effective to form a layer made of a highly crystalline compound. The present inventors have found that by using a physical vapor deposition method as a method for forming the first layer and the second layer, a layer made of a highly crystalline compound can be formed, and the coating has excellent abrasion resistance.

[0115] 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. A cathodic arc ion plating method having a high ionization rate of the raw material element may be used. When the cathodic arc ion plating method is used, it is possible to perform an ion bombardment treatment of a metal on the surface of the substrate before forming the first layer or the second layer, so that the adhesion between the substrate and the coating including the first layer or the second layer is significantly improved.

[0116] The cathodic arc ion plating method can be carried out, for example, by placing a substrate in an apparatus and a target as a cathode, and then applying a high voltage to the target to generate an arc discharge, thereby ionizing and evaporating the atoms that make up the target, and depositing the material on the substrate.

[0117] The balanced magnetron sputtering method can be carried out, for example, by placing a substrate in an apparatus, placing a target on a magnetron electrode equipped with a magnet that forms a balanced magnetic field, applying high-frequency power between the magnetron electrode and the substrate to generate a gas plasma, and causing gas ions generated by the generation of this gas plasma to collide with the target, thereby depositing atoms released from the target on the substrate.

[0118] The unbalanced magnetron sputtering method can be performed by, for example, unbalancing the magnetic field generated by the magnetron electrodes in the balanced magnetron sputtering method described above. Furthermore, the HiPIMS method can be used, which allows a high voltage to be applied and produces a dense film.

[0119] <Other processes> The second step may include a step of forming the first or second layer, as well as a step of surface treatment of the coating, such as polishing with a brush, dry or wet shot blasting, etc. The second step may also include a step of forming other layers, such as a base layer, a surface layer, and an intermediate layer. The other layers may be formed by a conventionally known chemical vapor deposition method or physical vapor deposition method. From the viewpoint that the other layers can be formed in succession in the form of the first unit layer and the second or third unit layer in one physical vapor deposition apparatus, it is preferable to form the other layers by a physical vapor deposition method. EXAMPLES

[0120] The present embodiment will be described more specifically with reference to examples, although the present embodiment is not limited to these examples.

[0121] [Example 1] <Samples 1 to 19, Samples 101 to 105> <Cutting tool manufacturing> FIG. 11 is a schematic cross-sectional view of the cathodic arc ion plating apparatus used in Example 1, and FIG. 12 is a schematic top view of the apparatus of FIG.

[0122] 11 and 12, a cathode 106 for a first unit layer, a cathode 107 for a second unit layer, and a cathode 120 for a surface layer, which are alloy targets serving as metal raw materials for the coating, and a rotatable substrate holder 104 for placing a substrate are installed in a chamber 101. The composition of the cathode 106 is adjusted so as to obtain the composition of the first unit layer shown in Table 1. The composition of the cathode 107 is adjusted so as to obtain the composition of the second unit layer shown in Table 1. The composition of the cathode 120 is adjusted so as to obtain the composition of the surface layer shown in Table 2.

[0123] An arc power supply 108 is attached to cathode 106, an arc power supply 109 is attached to cathode 107, and an arc power supply (not shown) is attached to cathode 120. A bias power supply 110 is attached to substrate holder 104. A gas inlet 105 through which gas 102 is introduced and a gas outlet 103 are provided in chamber 101 to adjust the pressure in chamber 101, and gas 102 in chamber 101 can be sucked out from gas outlet 103 by a vacuum pump.

[0124] The substrate holder 104 was fitted with a substrate made of cemented carbide of grade JIS K20, and a tip of JIS CNMG120408 and a tip of Sumitomo Electric Hardmetal Corp. SEMT13T3AGSN having a shape conforming to JIS.

[0125] Next, the pressure in the chamber 101 is reduced by the vacuum pump, and the substrate is heated to 600° C. by a heater installed in the apparatus while rotating. The pressure in the chamber 101 is reduced to 1.0×10 -4 The chamber was evacuated until the pressure reached 2.0 Pa. Next, argon gas was introduced from the gas inlet to maintain the pressure inside the chamber 101 at 2.0 Pa, and the voltage of the bias power supply 110 was gradually increased to -1000 V to clean the surface of the substrate for 15 minutes. Thereafter, the argon gas was exhausted from the chamber 101 to clean the substrate (argon bombardment treatment). In this manner, the substrate for each sample cutting tool was prepared.

[0126] Next, with the substrate rotated in the center, nitrogen was introduced as a reactive gas while maintaining the substrate temperature at 600°C, the reactive gas pressure at 3.3 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 150 A was supplied to each of the cathodes 106 and 107 to generate metal ions from the cathodes 106 and 107, thereby forming on the substrate a base layer having the composition shown in Table 2 and a first layer having the composition shown in Table 1.

[0127] When an underlayer was formed, the first layer was formed by alternately stacking the first unit layer and the second unit layer on the underlayer, one by one, in the number of layers shown in Table 1. When an underlayer was not formed, the first layer was formed by alternately stacking the first unit layer and the second unit layer on the substrate, one by one, in the number of layers shown in Table 1. The thickness of the underlayer, the thickness of each of the first unit layer and the second unit layer in the first layer, and the number of layers were adjusted by the rotation speed of the substrate. Then, the current supplied to the evaporation source was stopped when the thickness of the underlayer and the first layer became the thicknesses shown in Tables 1 and 2, respectively. The entry "-" in the "underlayer" column in Table 2 indicates that no underlayer was present.

[0128] Next, while introducing nitrogen gas and oxygen gas as reactive gases into the chamber 101, the temperature of the substrate was maintained at 500°C, the reactive gas pressure was maintained at 2.0 Pa, and the voltage of the bias power supply 110 was maintained at -350 V, and an arc current of 120 A was supplied to the cathode 120 to generate metal ions from the cathode 120 to form a surface layer on the first layer. When the thickness of the surface layer reached the thickness shown in Table 2, the current supplied to the evaporation source was stopped. The amount of nitrogen gas and oxygen gas introduced was adjusted so that the composition of the surface layer in Table 2 was obtained. In this manner, cutting tools of each sample were produced. The entry "-" in the "Surface layer" column in Table 2 indicates that no surface layer was present.

[0129] [Table 1]

[0130] [Table 2]

[0131] Evaluation <Measurement of the composition of the first unit layer> For each sample cutting tool, the composition of the first unit layer was measured by the method according to embodiment 1, and Ti 1-a Mo a The value of a at N was obtained. The results are shown in the "a" column of Table 1. In Table 1, "-" in the "a" column means that the first unit layer was not present.

[0132] <Measurement of the composition of the second unit layer> For each sample cutting tool, the composition of the second unit layer was measured by the method described in embodiment 1, and Al b V 1-b The value of b was obtained at N. The results are shown in the "b" column of Table 1.

[0133] <Measurement of the composition of the base layer and the surface layer> The compositions of the base layer and surface layer of each sample cutting tool were determined by the method described in embodiment 1. The results are shown in the "Composition" column of "Base layer" and the "Composition" column of "Surface layer" in Table 2. "-" in the "Composition" column of "Base layer" in Table 2 indicates that a base layer is not present, and "-" in the "Composition" column of "Surface layer" indicates that a surface layer is not present.

[0134] <Measurement of number of layers> For each sample cutting tool, the number of layers of the first unit layers and the number of layers of the second unit layers were determined by the method described in embodiment 1. For example, a number of layers of 10 indicates that the alternating layers include 10 first unit layers and 10 second unit layers. The results obtained are shown in the "Number of layers" column of Table 1.

[0135] <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 base layer, and the thickness of the surface layer> For each sample cutting tool, the average thickness of the first unit layer, the average thickness of the second unit layer, the thickness of the first layer, the thickness of the base layer, and the thickness of the surface layer were determined by the method described in embodiment 1. The results obtained are shown in the "Average thickness [μm]" of the "First unit layer", "Average thickness [μm]" of the "Second unit layer", and "Thickness [μm]" of the "First layer" in Table 1, and in the "Thickness [μm]" of the "Base layer" and "Thickness [μm]" of the "Surface layer" in Table 2. "-" indicates that the corresponding layer does not exist.

[0136] <λ2 / λ1 measurement> For each sample cutting tool, λ2 / λ1 was determined by the method described in embodiment 1. The results are shown in the "λ2 / λ1" column of Table 1. Note that "-" in the "λ2 / λ1" column of Table 1 means that at least one of the first unit layer and the second unit layer is absent.

[0137] <Measurement of the crystal structure of the first unit layer> For the cutting tools of each sample, XRD measurement was performed on the first unit layer to confirm the crystal structures of the first unit layer and the second unit layer. The specific method is as described in embodiment 1. For samples 1 to 19, it was confirmed that the first unit layer had a cubic crystal structure, and the second unit layer had a cubic crystal structure.

[0138] <Measurement of coating hardness> The hardness of the coating of Samples 1 to 19 was measured by the method described in Embodiment 1. It was confirmed that the hardness of the coating of these samples was within the range of 30 GPa or more and 55 GPa or less.

[0139] <Measurement of compressive residual stress of coating> The compressive residual stress of the coating of Samples 1 to 19 was measured by the method described in Embodiment 1. It was confirmed that the absolute value of the compressive residual stress of the coating of these samples was 6 GPa or less.

[0140] <Cutting test 1: Continuous turning test> A continuous turning test was performed on each sample CNMG120408-shaped cutting tool under the following cutting conditions, and the time until the flank wear of the cutting edge reached 0.2 mm was measured. The results are shown in the "Cutting time [min]" column of "Cutting test 1" in Table 2. A longer cutting time indicates a longer tool life. ≪Cutting conditions≫ ·Cutting material: Inconel 718 (HB400) ·Cutting speed: 90m / min Feed rate: 0.2mm / rev - Cutting depth: 1.5mm Coolant: Water-soluble The cutting process performed under the above cutting conditions corresponds to cutting process performed under conditions where the cutting edge temperature is high.

[0141] The cutting tools of Samples 1 to 19 correspond to Examples, and the cutting tools of Samples 101 to 105 correspond to Comparative Examples. It was confirmed that the cutting tools of Samples 1 to 19 have a longer tool life in cutting operations performed under conditions of high cutting edge temperatures, compared to the cutting tools of Samples 101 to 105.

[0142] <Cutting test 2: Milling test> For each sample, a cutting tool with a SEMT13T3AGSN shape was used, with the center line of the 150 mm wide plate aligned with the center of a wider cutter with a diameter of 160 mm, and surface milling was performed under the following cutting conditions, and the cutting length until the flank wear of the cutting edge reached 0.2 mm was measured. The results are shown in the "Cutting length [km]" column of "Cutting test 2" in Table 2. A longer cutting length indicates a longer tool life. ≪Cutting conditions≫ ·Work material: SKD11 (HB=235) ·Cutting speed: 200m / min Feed rate: 0.15mm / tooth Axial depth of cut ap: 1.5mm Radial cutting depth ae: 150mm Coolant: Dry The cutting process performed under the above cutting conditions corresponds to cutting process performed under conditions where the cutting edge temperature is high.

[0143] The cutting tools of Samples 1 to 19 correspond to Examples, and the cutting tools of Samples 101 to 105 correspond to Comparative Examples. It was confirmed that the cutting tools of Samples 1 to 19 have a longer tool life in cutting operations performed under conditions of high cutting edge temperatures, compared to the cutting tools of Samples 101 to 105.

[0144] [Example 2] <Samples 51 to 85, Samples 151 to 176> <Cutting tool manufacturing> The substrate of each cutting tool sample was prepared in the same manner as in Example 1. With the substrate rotated at the center, argon and nitrogen were introduced as reactive gases while maintaining the substrate temperature at 600°C, the reactive gas pressure at 2.0 Pa, and the voltage of the bias power supply 110 at a predetermined constant value in the range of -50V to -200V. An arc current of 100A was supplied to each of the cathodes 106 and 107 to generate metal ions from the cathodes 106 and 107, thereby forming an underlayer and a second layer having the compositions shown in Tables 3 to 6 on the substrate. The composition of the cathode 106 was adjusted so that the composition of the first unit layer in Tables 3 to 4 was obtained. The composition of the cathode 107 was adjusted so that the composition of the third unit layer in Tables 3 to 4 was obtained. The composition of the cathode 120 was adjusted so that the composition of the surface layer in Tables 5 to 6 was obtained.

[0145] When the underlayer was formed, the second layer was formed by alternately stacking the first unit layer and the third unit layer on the underlayer in the number of layers shown in Tables 3 to 4. When the underlayer was not formed, the second layer was formed by alternately stacking the first unit layer and the third unit layer on the substrate in the number of layers shown in Tables 3 to 4. The thickness of the underlayer, and the thickness and number of layers of the first unit layer and the third unit layer in the second layer were adjusted by the rotation speed of the substrate. Then, the current supplied to the evaporation source was stopped when the thickness of the underlayer and the second layer reached the thickness shown in Tables 3 to 6. The entry "-" in the "underlayer" column in Tables 5 to 6 indicates that the underlayer was not present.

[0146] Next, while introducing nitrogen gas and oxygen gas as reactive gas into the chamber 101, the temperature of the substrate was maintained at 350°C, the reactive gas pressure was maintained at 2.0 Pa, and the voltage of the bias power supply 110 was maintained at -350 V, and an arc current of 100 A was supplied to the cathode 120 to generate metal ions from the cathode 120 to form a surface layer on the second layer. When the thickness of the surface layer reached the thickness shown in Tables 5 and 6, the current supplied to the evaporation source was stopped. The amount of nitrogen gas and oxygen gas introduced was adjusted so that the composition of the surface layer in Tables 5 and 6 was obtained. In the above manner, cutting tools of each sample were produced. The entry "-" in the "Surface layer" column in Tables 5 and 6 indicates that no surface layer was present.

[0147] [Table 3]

[0148] [Table 4]

[0149] [Table 5]

[0150] [Table 6]

[0151] Evaluation For the cutting tools of each sample, the composition of the first unit layer, the composition of the third unit layer, the composition of the underlayer, the composition of the surface layer, the number of layers of each of the first unit layer and the third unit layer, the average thickness of the first unit layer, the average thickness of the third unit layer, the thickness of the second layer, the thickness of the underlayer, the thickness of the surface layer, λ3 / λ1 and the crystal structure of the first unit layer, the hardness of the coating, and the compressive residual stress of the coating were measured. The measurement method for each item was as described in Example 1. The results are shown in Tables 3 to 6.

[0152] In Sample 51 to Sample 85, it was confirmed that the first unit layer had a cubic crystal structure, and the second unit layer had a cubic crystal structure. It was confirmed that the hardness of the coating of Sample 51 to Sample 85 was within a range of 30 GPa or more and 55 GPa or less. It was confirmed that the absolute value of the compressive residual stress of the coating of Sample 51 to Sample 85 was 6 GPa or less.

[0153] <Cutting test 3: Continuous turning test> A continuous turning test was performed on each sample of cutting tools with a CNMG120408 shape under the following cutting conditions, and the time until the flank wear of the cutting edge reached 0.2 mm was measured. The results are shown in the "Cutting time [min]" column of "Cutting test 3" in Tables 5 and 6. In Tables 5 and 6, a longer cutting time indicates a longer tool life. (Cutting conditions) ·Work material: SCM440 (HB320) ·Cutting speed: 360m / min Feed rate: 0.35mm / rev Depth of cut: 2.0mm Coolant: Water-soluble The cutting process performed under the above cutting conditions corresponds to cutting process performed under conditions where the cutting edge temperature is high.

[0154] The cutting tools of Samples 51 to 85 correspond to the Examples, and the cutting tools of Samples 151 to 176 correspond to the Comparative Examples. It was confirmed that the cutting tools of Samples 51 to 85 have a longer tool life in cutting operations performed under conditions of high cutting edge temperatures, compared to the cutting tools of Samples 151 to 176.

[0155] <Cutting test 4: Milling test> For each sample, the cutting tool with the shape of SEMT13T3AGSN was surface milled under the following cutting conditions, with the center line of the 150 mm wide plate aligned with the center of the wider cutter with a diameter of 160 mm, and the cutting length until the flank wear of the cutting edge reached 0.2 mm was measured. The results are shown in the "Cutting length [km]" column of "Cutting test 4" in Tables 5 and 6. Note that in Tables 5 and 6, a longer cutting length indicates a longer tool life. ≪Cutting conditions≫ ·Work material:FCD700(HB=250) ·Cutting speed: 220m / min Feed rate: 0.2mm / tooth Axial depth of cut ap: 2.0mm Radial cut ae: 150mm Coolant: Dry The cutting process performed under the above cutting conditions corresponds to cutting process performed under conditions where the cutting edge temperature is high.

[0156] The cutting tools of Samples 51 to 85 correspond to the Examples, and the cutting tools of Samples 151 to 176 correspond to the Comparative Examples. It was confirmed that the cutting tools of Samples 51 to 85 have a longer tool life in cutting operations performed under conditions of high cutting edge temperatures, compared to the cutting tools of Samples 151 to 176.

[0157] Although the embodiments and examples of the present disclosure have been described above, it is intended from the outset that the configurations of the above-described embodiments and examples may be appropriately combined or modified in various ways. The embodiments and examples disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the embodiments and examples described above, and is intended to include the meaning equivalent to the claims and all modifications within the scope. [Explanation of symbols]

[0158] 1 cutting tool, 2 substrate, 3 coating, 12 first unit layer, 13 first layer, 13A second layer, 14 surface layer, 15 second unit layer, 16 base layer, 17 third unit layer, 101 chamber, 102 gas, 103 gas exhaust port, 104 substrate holder, 105 gas inlet port, 106, 107, 120 cathode, 108, 109 arc power supply, 110 bias power supply.

Claims

1. 1. A cutting tool comprising a substrate and a coating disposed on the substrate, the coating comprises a first layer; the first layer is composed of alternating layers in which first unit layers and second unit layers are alternately stacked, The first unit layer is made of Ti １－ａ Mo ａ It consists of N, a is 0.01 or more and 0.20 or less, The second unit layer is Al ｂ V １－ｂ It consists of N, The cutting tool, wherein b is equal to or greater than 0.40 and equal to or less than 0.

80.

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

4. the coating further includes a surface layer provided on the side of the first layer opposite to the substrate, 3. The cutting tool according to claim 1, wherein the surface layer is made of TiMoON or AlVON.

5. 1. A cutting tool comprising a substrate and a coating disposed on the substrate, the coating comprises a second layer; the second layer is composed of alternating layers in which first unit layers and third unit layers are alternately stacked, The first unit layer is made of Ti １－ａ Mo ａ It consists of N, a is 0.01 or more and 0.20 or less, The third unit layer is Al ｃ V １－ｃ－ｄ X ｄ It consists of N, X is one or two elements selected from the group consisting of boron, silicon, scandium, yttrium, and cerium; The c is 0.40 or more and 0.80 or less, The cutting tool, wherein d is equal to or greater than 0.001 and equal to or less than 0.

05.

6. 6. The cutting tool according to claim 5, wherein, in the first unit layer and the third unit layer adjacent to the first unit layer, a 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.

7. the average thickness of the first unit layer is 0.002 μm or more and 0.2 μm or less, The cutting tool according to claim 5 or 6, wherein the third unit layer has an average thickness of 0.002 μm or more and 0.2 μm or less.

8. the coating further includes a surface layer provided on the side of the second layer opposite the substrate, the surface layer is made of TiMoON or AlVXON, 7. The cutting tool according to claim 5, wherein X is one or two elements selected from the group consisting of boron, silicon, scandium, yttrium, and cerium.

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