Cutting tool

Abstract

A cutting tool comprising a substrate and a coating that is disposed upon the substrate, wherein: the coating includes a first layer; the first layer is formed from alternating layers consisting of first unit layers and second unit layers stacked in an alternating manner; each first unit layer is composed of Ti1-a-bAlaScbN; a is 0.350 to 0.650 inclusive; b is 0.010 to 0.100 inclusive; each second unit layer is composed of TicSi1-cN; and c is 0.20 to 0.99 inclusive.

Description

cutting tools

[0001] This disclosure relates to cutting tools.

[0002] Conventionally, cutting tools comprising a base material and a coating that covers the base material have been used in cutting processes. For example, Patent Documents 1 and 2 disclose cutting tools in which the base material is coated with a coating formed by adding one or more elements selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements, Si, Y, and rare earth elements to a nitride or carbonitride mainly composed of Ti and Al.

[0003] International Publication No. 1997 / 034023, Japanese Patent Publication No. 2015-54995

[0004] The cutting tool of the present disclosure comprises a base material and a coating disposed on the base material, wherein the coating includes a first layer, the first layer consists of alternating layers in which a first unit layer and a second unit layer are alternately stacked, and the first unit layer is made of Ti １－ａ－ｂ Al ａ Sc ｂ It consists of N, where a is 0.350 or more and 0.650 or less, b is 0.010 or more and 0.100 or less, and the second unit layer is Ti ｃ Si １－ｃ A cutting tool consisting of N, wherein c is between 0.20 and 0.99.

[0005] Figure 1 is a schematic enlarged cross-sectional view of an example of a cutting tool according to Embodiment 1. Figure 2 is a schematic enlarged cross-sectional view of another example of a cutting tool according to Embodiment 1. Figure 3 is a schematic enlarged cross-sectional view of another example of a cutting tool according to Embodiment 1. Figure 4 is a schematic enlarged cross-sectional view of another example of a cutting tool according to Embodiment 1. Figure 5 is a diagram illustrating an example of the ratio of the thicknesses of the first unit layer and the second unit layer. Figure 6 is a schematic enlarged cross-sectional view of an example of a cutting tool according to Embodiment 2. Figure 7 is a schematic enlarged cross-sectional view of another example of a cutting tool according to Embodiment 2. Figure 8 is a schematic enlarged cross-sectional view of another example of a cutting tool according to Embodiment 2. Figure 9 is a schematic enlarged cross-sectional view of another example of a cutting tool according to Embodiment 2. Figure 10 is a diagram illustrating an example of the ratio of the thicknesses of the first unit layer and the third unit layer. Figure 11 is a schematic cross-sectional view of a cathode arc ion plating apparatus used in the embodiment. Figure 12 is a schematic top view of the cathode arc ion plating apparatus shown in Figure 11.

[0006] [Issues this disclosure aims to address] In recent years, there has been growing interest in the SDGs (Sustainable Development Goals) in the field of machining, with the goal of realizing a sustainable and better world by 2030.

[0007] In machining processes, machine tools are used. The majority of the energy source for operating machine tools is electricity. To achieve decarbonization, it is important to reduce the energy used during machine operation. It has been reported that approximately 53% of the energy consumed by machine tools is related to cutting fluid (coolant). Furthermore, cutting fluid ultimately becomes sludge containing metal powder and is treated as industrial waste.

[0008] From the perspective of SDGs and environmental protection, there is a demand for dry machining without the use of cutting fluids and for improved machining efficiency. In dry machining and high-efficiency machining, the cutting edge temperature becomes high during cutting.

[0009] Therefore, the present disclosure aims to provide a cutting tool that can have excellent tool life, especially under cutting conditions where the cutting edge temperature becomes high.

[0010] [Effect of the Present Disclosure] According to the present disclosure, it is possible to provide a cutting tool that can have an excellent tool life even under cutting conditions where the cutting edge temperature becomes high.

[0011] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. (1) The cutting tool of the present disclosure is a cutting tool including a substrate and a coating disposed on the substrate, wherein the coating includes a first layer, and the first layer is composed of an alternating layer in which a first unit layer and a second unit layer are alternately laminated, and the first unit layer is Ti １－ａ－ｂ Al ａ Sc ｂ N, where a is 0.350 or more and 0.650 or less, b is 0.010 or more and 0.100 or less, and the second unit layer is Ti ｃ Si １－ｃ N, where c is 0.20 or more and 0.99 or less, and is a cutting tool.

[0012] According to the present disclosure, it is possible to provide a cutting tool that can have an excellent tool life even under cutting conditions where the cutting edge temperature becomes high. The reason is presumed as follows.

[0013] In the Ti １－ａ－ｂ Al ａ Sc ｂ N of the first unit layer, Sc is oxidized under high-temperature cutting conditions, and a passivation layer composed of Sc ２ O ３ is generated in the coating. Since the melting point of Sc ２ O ３ is as high as 2485 °C, the passivation layer composed of Sc ２ O ３ can exist stably even under high-temperature cutting conditions. Therefore, the stability of the performance of the cutting tool is improved even under high-temperature cutting conditions.

[0014] Sc ２ O ３Because it precipitates at the grain boundaries of TiAlScN, creating a so-called "wedge effect," it can prevent oxygen from diffusing from the surface of the coating through the grain boundaries into the interior of the coating. The wedge effect significantly improves the oxidation resistance of the coating. Furthermore, the wedge effect can suppress the reactivity between the workpiece and the coating, thereby reducing the coefficient of friction between the workpiece and the coating.

[0015] The lattice constant of ScN is 4.51 Å, which is greater than the lattice constant of TiN (4.23 Å) and AlN (4.12 Å). Therefore, the presence of Sc in the first unit layer introduces strain into the first unit layer, refining its structure. This increases the hardness of the first unit layer and improves the wear resistance of the coating including the first layer.

[0016] Patent documents 1 and 2 disclose coatings obtained by adding yttrium to nitrides or carbonitrides (hereinafter also referred to as "TiAlN or TiAlCN") mainly composed of Ti and Al. However, since the lattice constant of YN is large at 4.88 Å, the amount that can be dissolved in TiAlN or TiAlCN is limited. For this reason, TiAlN or TiAlCN with added yttrium has insufficient strain introduction, and the effect of increasing the hardness and improving the wear resistance of the coating is insufficient.

[0017] Ti in the first unit layer １－ａ－ｂ Al ａ Sc ｂ N is Ti of the second unit layer ｃ Si １－ｃ Compared to N, it has superior heat resistance. Therefore, even at high temperatures, thermal wear of the first unit layer is suppressed, and the first layer can maintain excellent wear resistance.

[0018] Ti in the second unit layer ｃ Si １－ｃ N consists of nanometer-sized cubic TiN crystals and amorphous SiN. ｘIt is presumed to have a so-called nanocomposite structure in which these materials are mixed. The second unit layer having a nanocomposite structure becomes extremely hard, resulting in an excellent balance of wear resistance, heat insulation, oxidation resistance, and toughness. Therefore, the first layer, including the second unit layer, contributes to extending the lifespan of cutting tools.

[0019] Ti in the second unit layer ｃ Si １－ｃ N is Ti of the first unit layer １－ａ－ｂ Al ａ Sc ｂ Compared to N, it has a larger compressive residual stress, which contributes to improving the chipping resistance of the first layer.

[0020] One example of a workpiece material is alloy tool steel, which sometimes contains other alloying elements such as Cr. If Cr is contained in the coating, the components of the coating and the workpiece material will mutually diffuse during cutting, accelerating wear. Therefore, it is preferable for the coating not to contain Cr. In the cutting tool of Embodiment 1, the first layer does not contain Cr, so wear due to mutual diffusion between the coating and the components of the workpiece material that contain Cr is suppressed.

[0021] The first layer consists of alternating layers in which the first unit layer and the second unit layer are stacked alternately. Therefore, even under high-temperature cutting conditions, the first layer can combine the effects of the first unit layer, which improves the stability, oxidation resistance, heat resistance, and wear resistance of the coating, as well as the effect of reducing the coefficient of friction, with the effects of the second unit layer, which improves the wear resistance, heat barrier resistance, chipping resistance, and oxidation resistance of the coating.

[0022] The first layer consists of alternating layers in which the first unit layer and the second unit layer are stacked alternately. At the interface between the first unit layer and the second unit layer, the composition and crystal lattice are discontinuous. Therefore, if a crack occurs from the surface of the coating during cutting, crack propagation can be suppressed at the interface. In coatings including the first layer, chipping and chipping are suppressed.

[0023] For the reasons stated above, a cutting tool including a first layer consisting of alternating layers in which a first unit layer and a second unit layer are stacked alternately can have excellent tool life, especially under cutting conditions where the cutting edge temperature becomes high.

[0024] (2) In (1) above, the ratio of the thickness λ1 of the first unit layer to the thickness λ2 of the second unit layer, λ1 / λ2, may be 1 or more and 5 or less.

[0025] The first unit layer has high oxidation resistance and superior heat resistance compared to the second unit layer. When λ1 / λ2 is between 1 and 5, the proportion of the first unit layer in the first layer increases, further improving the oxidation resistance and heat resistance of the first layer. Therefore, even under cutting conditions where the cutting edge temperature is high, wear of the coating is less likely to occur, and the tool life of the cutting tool is further improved.

[0026] Furthermore, when λ1 / λ2 is 1 or greater, the abrasion resistance of the coating improves. On the other hand, when λ1 / λ2 is 5 or less, the crack propagation suppression effect due to the lamination of the first and second unit layers tends to be easily obtained.

[0027] (3) In (1) or (2) above, the average thickness of the first unit layer may be 2 nm or more and 200 nm or less, and the average thickness of the second unit layer may be 2 nm or more and 200 nm or less. This further improves the effect of suppressing the propagation of cracks that occur on the surface of the coating.

[0028] (4) In any of (1) to (3) above, the coating further includes a second layer disposed between the substrate and the first layer, wherein the composition of the second layer is the same as the composition of either the first unit layer or the second unit layer, the thickness of the second layer is greater than the average thickness of the unit layers having the same composition, and the thickness of the second layer may be 0.1 μm or more and 1.0 μm or less. This makes it possible to improve the adhesion between the substrate and the coating.

[0029] (5) In any of (1) to (4) above, the coating further includes a third layer provided on the side of the first layer opposite to the substrate, the third layer being made of TiCN or TiAlScCN, and the thickness of the third layer may be 0.1 μm or more and 1.0 μm or less.

[0030] Generally, carbonitrides tend to have a lower coefficient of friction with respect to the workpiece than nitrides. This reduction in the coefficient of friction is thought to be due to the contribution of carbon atoms. When the coating includes a third layer, the coefficient of friction of the coating with respect to the workpiece decreases, further extending the life of the cutting tool.

[0031] (6) In any of (1) to (5) above, the thickness of the first layer may be 0.5 μm or more and 15 μm or less. When the thickness of the first layer is 0.5 μm or more, improvements in the hardness, wear resistance, heat resistance, oxidation resistance, and chipping resistance of the first layer are easily obtained, and the lifespan of the cutting tool is further extended. When the thickness of the first layer is 15 μm or less, chipping resistance is easily and stably exhibited.

[0032] (7) A cutting tool of the present disclosure comprises a base material and a coating disposed on the base material, wherein the coating includes a layer A, and the layer A consists of alternating layers in which a first unit layer and a third unit layer are alternately stacked, and the first unit layer is Ti １－ａ－ｂ Al ａ Sc ｂ It consists of N, where a is 0.350 or more and 0.650 or less, b is 0.010 or more and 0.100 or less, and the third unit layer is Ti ｄ Si １－ｄ－ｅ B ｅ A cutting tool comprising N, wherein d is between 0.20 and 0.99, and e is greater than 0 and less than or equal to 0.05.

[0033] According to this disclosure, it is possible to provide a cutting tool that can have excellent tool life, especially under cutting conditions where the cutting edge temperature becomes high. The reason for this is presumed to be the same as the reason described in (1) above. The following reasons are also presumed to be the case in this disclosure.

[0034] Ti of the third unit layer ｄ Si １－ｄ－ｅ B ｅ In N, the hardness of the third unit layer is increased by boron, thereby increasing the overall hardness of the coating. Furthermore, the boron oxide formed during cutting has a low melting point, so it acts as a lubricant during cutting, suppressing the adhesion of the workpiece to the cutting tool.

[0035] (8) In (7) above, the ratio of the thickness λ1 of the first unit layer to the thickness λ3 of the third unit layer, λ1 / λ3, may be 1 or more and 5 or less.

[0036] According to this, for the same reasons as in (2) above, the heat resistance and oxidation resistance of layer A are further improved, and the tool life of the cutting tool is further improved.

[0037] (9) In (7) or (8) above, the average thickness of the first unit layer may be 2 nm or more and 200 nm or less, and the average thickness of the third unit layer may be 2 nm or more and 200 nm or less. This further improves the effect of suppressing the propagation of cracks that occur on the surface of the coating.

[0038] (10) In any of (7) to (9) above, the coating further includes a B layer disposed between the substrate and the A layer, the composition of the B layer being the same as the composition of either the first unit layer or the third unit layer, the thickness of the B layer being greater than the average thickness of the unit layers having the same composition, and the thickness of the B layer may be 0.1 μm or more and 1 μm or less. This makes it possible to improve the adhesion between the substrate and the coating.

[0039] (11) In any of (7) to (10) above, the coating further includes a C layer provided on the side of the A layer opposite to the substrate, the C layer is made of TiCN or TiAlScCN, and the thickness of the C layer may be 0.1 μm or more and 1.0 μm or less. This reduces the friction coefficient of the coating with respect to the workpiece, further extending the life of the cutting tool.

[0040] (12) In any of (7) to (111) above, the thickness of layer A may be 0.5 μm or more and 15 μm or less. When the thickness of layer A is 0.5 μm or more, improvements in the hardness, wear resistance, heat resistance, oxidation resistance, and chipping resistance of layer A are easily obtained, and the lifespan of the cutting tool is further extended. When the thickness of layer A is 15 μm or less, chipping resistance is easily and stably exhibited.

[0041] [Details of Embodiments of the Disclosure] Specific examples of the cutting tools of the Disclosure will be described below with reference to the drawings. In the drawings of the Disclosure, the same reference numerals indicate the same part or a corresponding part. In addition, dimensional relationships such as length, width, thickness, and depth have been modified as appropriate for clarity and simplification of the drawings and do not necessarily represent actual dimensional relationships.

[0042] In this disclosure, the notation "A to B" means A or greater and B or less. If no unit is specified for A, and only a unit is specified for B, then the unit for A and the unit for B are the same.

[0043] In this disclosure, when compounds and the like are represented by chemical formulas, unless otherwise specified, the atomic ratios should include all conventionally known atomic ratios and should not necessarily be limited to those within the stoichiometric range.

[0044] In this disclosure, if one or more numerical values ​​are listed as the lower limit and upper limit of a numerical range, any combination of any one numerical value listed as the lower limit and any one numerical value listed as the upper limit shall also be disclosed.

[0045] In this disclosure, “equipment,” “includes,” “possesses,” and variations thereof are open-ended terms. Open-ended terms may or may not include additional elements in addition to the essential elements. The statement “consists of” is a closed term. However, even a configuration expressed in closed terms may include additional elements that are usually incidental or irrelevant to the subject technology.

[0046] [Embodiment 1: Cutting Tool (1)] A cutting tool according to one embodiment of the present disclosure (hereinafter also referred to as "Embodiment 1") will be described with reference to Figures 1 to 5. The cutting tool 1 of Embodiment 1 is a cutting tool 1 comprising a base material 2 and a coating 3 disposed on the base material 2. The coating 3 includes a first layer 13. The first layer 13 consists of alternating layers in which a first unit layer 12 and a second unit layer 15 are alternately stacked. The first unit layer 12 is Ti １－ａ－ｂ Al ａ Sc ｂIt consists of N. Here, a is between 0.350 and 0.650, and b is between 0.010 and 0.100. The second unit layer 15 is Ti ｃ Si １－ｃ It consists of N, where c is between 0.20 and 0.99.

[0047] ≪Cutting Tools≫ The cutting tools of Embodiment 1 can be suitably used as drills, end mills, replaceable cutting tips for drills, replaceable cutting tips for end mills, replaceable cutting tips for milling, replaceable cutting tips for turning, metal saws, gear cutting tools, reamers, taps, etc.

[0048] <Substrate> Any composition of the substrate that is conventionally known can be used. For example, cemented carbide (WC-based cemented carbide, cemented carbide containing WC and Co, cemented carbide with added carbonitrides such as Ti, Ta, and Nb, etc.), cermet (mainly composed of TiC, TiN, TiCN, etc.), high-speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, etc.), cubic boron nitride sintered body, or diamond sintered body can be used.

[0049] The base material composition may be WC-based cemented carbide or cermet (especially TiCN-based cermet) from the viewpoint of having an excellent balance between hardness and strength at high temperatures. A base material made of WC-based cemented carbide or cermet can contribute to extending the lifespan of cutting tools.

[0050] <Coating> In the cutting tool of Embodiment 1, the coating can cover at least the portion of the substrate that is involved in cutting. The portion of the substrate that is involved in cutting means, for example, an area on the surface of the substrate that is within 100 μm of the cutting edge. The coating may cover the entire surface of the substrate, or it may cover the entire surface of the portion of the substrate that is involved in cutting. As long as the effects of the cutting tool of this disclosure are not impaired, the absence of a coating on a portion of the portion of the substrate that is involved in cutting does not deviate from the scope of Embodiment 1. As long as the effects of the cutting tool of this disclosure are not impaired, partial differences in the coating configuration do not deviate from the scope of Embodiment 1.

[0051] As shown in Figures 1 and 2, the coating 3 includes a first layer 13, and the first layer 13 may be provided directly on the substrate 2.

[0052] The coating 3 may include other layers in addition to the first layer 13. As shown in Figures 3 to 4, the coating 3 may include a second layer 16 positioned between the substrate 2 and the first layer 13. As shown in Figures 1 to 4, the coating 3 may include a third layer 14 provided on the side of the first layer 13 opposite to the substrate 2.

[0053] The thickness of the coating may be 0.5 μm or more and 25 μm or less, 1.0 μm or more and 23 μm or less, or 5.0 μm or more and 20 μm or less.

[0054] The thickness of the coating is measured by observing the cross-section of the coating using a scanning electron microscope (SEM). Specifically, the observation magnification of the cross-sectional sample is set to 5000 to 10000 times, and the observation area is 100 to 500 μm². ２ The thickness width is measured at three points within a single field of view, and the average value is taken as the thickness of the coating. The thickness of each layer described later is measured in the same manner unless otherwise specified.

[0055] The compressive residual stress of the coating may be 6 GPa or less in absolute value. The compressive residual stress of the coating is a type of internal stress (inherent strain) present throughout the coating, and is expressed as a negative value (unit: in this embodiment, "GPA" is used). Therefore, the concept of a large compressive residual stress indicates that the absolute value of the numerical value is large, and the concept of a small compressive residual stress indicates that the absolute value of the numerical value is small. In other words, an absolute value of 6 GPa or less for the compressive residual stress means that the preferred compressive residual stress for the coating is between -6 GPa and 0 GPa.

[0056] When the compressive residual stress of the coating exceeds 0 GPa, it becomes tensile stress, making it difficult to suppress the propagation of cracks that originate from the outermost surface of the coating. On the other hand, if the absolute value of the compressive residual stress exceeds 6 GPa, the stress is too high, and there is a risk that the coating will peel off, especially from the edge of the cutting tool, before cutting begins, shortening the life of the cutting tool.

[0057] The compressive residual stress of the coating can be measured using an X-ray residual stress analyzer by the sin²ψ method (see pages 54-66 of "X-ray Stress Measurement Method" (Japan Society for Materials Science, published by Yokendo Co., Ltd., 1981)).

[0058] The crystal structure of the coating may be cubic. A cubic crystal structure improves the hardness of the coating. The crystal structure of each layer within the coating may also be cubic. The crystal structures of the coating and each layer within it can be analyzed using an X-ray diffractometer known in this field.

[0059] The hardness of the coating may be between 30 GPa and 55 GPa, or between 35 GPa and 50 GPa. In this case, the coating will have sufficient hardness. The overall hardness of the coating can be measured using the nanoindenter method (Nano Indenter XP, manufactured by MTS). Specifically, the measurement is performed according to ISO 14577, with a measurement load of 10 mN (1 gf), and the hardness is measured at three points on the surface of the coating. The average value of these measurements is taken as the "hardness".

[0060] <First Layer> In the cutting tool of Embodiment 1, the first layer consists of alternating layers in which a first unit layer and a second unit layer are stacked alternately. The fact that the first layer consists of alternating layers in which a first unit layer and a second unit layer are stacked alternately can be confirmed by observing a thin section sample including the cross-section of the coating with a TEM (transmission electron microscope) and observing the difference in contrast.

[0061] The first unit layer and the second unit layer may be positioned as close as possible to the substrate side. The first unit layer 12 and the second unit layer 15 may be positioned as close as possible to the surface side of the coating 3.

[0062] The thickness of the first layer 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.

[0063] 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 along the normal to the surface of the coating, and a thin section sample including the cross-section is prepared. The thin section sample is observed with a TEM. The observation magnification should be 20,000 to 5,000,000 times, and the measurement field should be 0.0016 to 80 μm. ２ The following procedure is followed: Within one field of view, the thickness width of the first layer is measured at three locations, and the average of these three thickness widths is taken as the thickness of the first layer.

[0064] <Composition of the first unit layer and the second unit layer> The first unit layer is Ti １－ａ－ｂ Al ａ Sc ｂ It consists of N, where a is between 0.350 and 0.650, and b is between 0.010 and 0.100.

[0065] The above value a is 0.350 or more and 0.650 or less, but may also be 0.400 or more and 0.600 or less, or 0.450 or more and 0.550 or less.

[0066] The above value b is 0.010 or more and 0.100 or less, and may also be 0.020 or more and 0.090 or less, or 0.030 or more and 0.080 or less, or 0.040 or more and 0.070 or less.

[0067] In this disclosure, "the first unit layer is Ti １－ａ－ｂ Al ａ Sc ｂ "Consists of N" means that, insofar as the effects of this disclosure are not impaired, the first unit layer is Ti １－ａ－ｂ Al ａ Sc ｂ This means that, in addition to nitrogen, unavoidable impurities may be included. Examples of unavoidable impurities include oxygen, argon, and carbon. The total content of unavoidable impurities in the first unit layer may be greater than 0 atomic percent and less than 1 atomic percent.

[0068] The above a and b are determined by measuring the energy and number of characteristic X-rays generated when an electron beam is irradiated onto a cross-section of a thin section of the coating using an energy-dispersive X-ray spectrometer (EDX) attached to a transmission electron microscope (TEM), and then performing elemental analysis. (See Al below) ｃ Cr１－ｃ c and Al in N ｄ Cr １－ｄ－ｅ M ｅ d and e in N are also measured in the same way.

[0069] The second unit layer is Ti ｃ Si １－ｃ consisting of N, c is 0.20 or more and 0.99 or less. c may be 0.25 or more and 0.95 or less, or may be 0.30 or more and 0.90 or less.

[0070] In the present disclosure, "the second unit layer consists of Ti ｃ Si １－ｃ N" means that as long as the effects of the present disclosure are not impaired, the second unit layer is Ti ｃ Si １－ｃ N and may contain inevitable impurities. Examples of inevitable impurities include oxygen and carbon. The total content rate of inevitable impurities in the second unit layer may be more than 0 atomic % and less than 1 atomic %.

[0071] In the present disclosure, the composition of the first unit layer Ti １－ａ－ｂ Al ａ Sc ｂ In N, the ratio A of the total number of atoms A of Ti, Al, and Sc Ｍ１ to the number of atoms A of N Ｎ１ A Ｎ１ / A Ｍ１ is 0.8 or more and 1.2 or less. In the present disclosure, the composition of the second unit layer Ti ｃ Si １－ｃ In N, the ratio A of the total number of atoms A of Ti and Si Ｍ２ to the number of atoms A of N Ｎ２ A Ｎ２ / A Ｍ２ is 0.8 or more and 1.2 or less. The ratio A Ｎ１ / A Ｍ１ and the ratio A Ｎ２ / A Ｍ２ can be measured by the Rutherford backscattering (RBS) method. If the ratio A Ｎ１ / A Ｍ１ and the ratio A Ｎ２ / A Ｍ２ are within the above range, it has been confirmed that the effects of the present disclosure are not impaired.

[0072] <Average thickness of the first unit layer and the average thickness of the second unit layer> The average thickness of the first unit layer may be 2 nm or more and 200 nm or less, and the average thickness of the second unit layer may be 2 nm or more and 200 nm or less. The average thickness of the first unit layer may be 5 nm or more and 150 nm or less, or 10 nm or more and 100 nm or less. The average thickness of the second unit layer may be 5 nm or more and 150 nm or less, or 10 nm or more and 100 nm or less.

[0073] 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 described above.

[0074] As shown in Figure 5, in the first unit layer 12 and the second unit layer 15 adjacent to the first unit layer 12, the ratio λ1 / λ2 of the thickness of the first unit layer 12 to the thickness λ2 (nm) of the second unit layer 15 may be 1 or more and 5 or less, 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.

[0075] In Figure 5, for illustrative purposes, the thickness of all first unit layers 12 is shown as λ1 and the thickness of all second unit layers 15 is shown as λ2. However, as long as the above λ1 / λ2 relationship is satisfied between adjacent first and second unit layers, the thickness λ1 of all first unit layers 12 does not need to be the same, nor does the thickness λ2 of all second unit layers 15 need to be the same.

[0076] In the first layer, the number of layers of the first unit layer and the second unit layer may be 5 to 500, 10 to 500, 100 to 400, or 200 to 350. By laminating the first unit layer and the second unit layer, it is possible to obtain the effect of improving the hardness, oxidation resistance, wear resistance, heat resistance, and chipping resistance of the first layer in a well-balanced manner.

[0077] In the first layer, the number of stacked layers of each of the first unit layer and the second unit layer is measured by observing a thin sample of the cross-section of the coating at an observation magnification of 20,000 to 5,000,000 times with a TEM (transmission electron microscope). The number of stacked layers of each of the first unit layer and the third unit layer in the A layer described later is also measured by the same method.

[0078] <Second layer> In the cutting tool of Embodiment 1, the coating may further include a second layer disposed between the base material and the first layer. The composition of the second layer may be the same as the composition of any one of the first unit layer and the second unit layer. The second layer may be disposed directly above the base material.

[0079] When the composition of the second layer is the same as the composition of the first unit layer, even when the second layer is exposed at the initial stage of cutting, passivation composed of Sc ２ O ３ is generated, and the stability of the performance of the cutting tool is improved. Further, due to the wedge effect of Sc ２ O ３ , oxidation of the coating can be suppressed. Further, due to the wedge effect, the reactivity between the workpiece and the coating can be suppressed, and the friction coefficient between the workpiece and the coating can be reduced.

[0080] When the composition of the second layer is the same as the composition of the first unit layer, the thickness of the second layer may be larger than the thickness of the first unit layer. Thereby, the stability of the performance of the cutting tool due to the formation of Sc ２ O ３ , the oxidation suppression effect of the coating, and the reactivity suppression effect between the workpiece and the coating are further improved. Also, the friction coefficient between the workpiece and the coating can be further reduced.

[0081] When the composition of the second layer is the same as the composition of the first unit layer, as shown in FIG. The second unit layer 15 may be stacked directly above the second layer 16. When the composition of the second layer is the same as the composition of the first unit layer and the first unit layer is stacked directly above the second layer, the second layer and the first unit layer have a continuous crystal structure.

[0082] When the composition of the second layer is the same as that of the second unit layer, the second unit layer tends to have a large compressive residual stress. Therefore, the coating's resistance to chipping can be improved, especially in intermittent machining where repeated loads are applied to the cutting edge.

[0083] The thickness of the second layer may be more than 1 times and 500 times or less the thickness of the unit layer having the same composition, or it may be 2 times or more and 500 times or less, or 4 times or more and 120 times or less, or it may be 10 times or more and 50 times or less.

[0084] The thickness of the second layer 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 1 μm or less. This makes it easier to obtain the above-mentioned effects by placing the second layer.

[0085] If the composition of the second layer is the same as the composition of the second unit layer, the first unit layer 12 may be laminated directly on top of the second layer 16, as shown in Figure 3. Alternatively, the second unit layer 15 may be laminated directly on top of the second layer 16, as shown in Figure 4. When the composition of the second layer is the same as the composition of the second unit layer, and the second unit layer is laminated directly on top of the second layer, the second layer and the second unit layer have a continuous crystalline structure.

[0086] <Third Layer> In the cutting tool of Embodiment 1, the coating may further include a third layer provided on the side opposite to the substrate of the first layer. The third layer may be located on the outermost surface of the coating. The third layer may be made of TiCN or TiAlScCN.

[0087] When the third layer consists of TiCN, it is possible to impart a predetermined color by adjusting the composition ratio of N and C. This allows for the addition of aesthetic appeal and distinctiveness to the appearance of cutting tools, making them commercially useful.

[0088] When the third layer is made of TiAlScCN, under high-temperature cutting conditions, ２ O ３ A passivation is generated, improving the stability of the cutting tool's performance.

[0089] When the third layer consists of TiAlScCN, the atomic ratio of Ti, Al, and Sc in the third layer may be the same as the atomic ratio of Ti, Al, and Sc in the first unit layer. Specifically, if the atomic ratio of Ti, Al, and Sc in the first unit layer is Ti:Al:Sc = 1-a-b:a:b, then the atomic ratio of Ti, Al, and Sc in the third layer may also be Ti:Al:Sc = 1-a-b:a:b. According to this, when the coating is manufactured by the PVD method, the first unit layer and the third layer can be manufactured using the same target, which is advantageous in terms of cost.

[0090] The thickness of the third layer may be between 0.1 μm and 1.0 μm. When the thickness of the third layer is 0.1 μm or more, the above effects are good when the third layer is placed. Considering cost, the thickness of the third layer may be 1.0 μm or less. The thickness of the third layer may also be between 0.3 μm and 0.8 μm, or between 0.5 μm and 0.6 μm.

[0091] [Embodiment 2: Cutting Tool (2)] A cutting tool according to another embodiment of the present disclosure will be described with reference to Figures 6 to 10. The cutting tool of Embodiment 2 is a cutting tool comprising a base material and a coating disposed on the base material. The coating includes layer A. Layer A consists of alternating layers in which a first unit layer and a third unit layer are alternately laminated. The first unit layer is Ti １－ａ－ｂ Al ａ Sc ｂ It consists of N. Here, a is between 0.350 and 0.650, and b is between 0.010 and 0.100. The third unit layer is Ti ｄ Si １－ｄ－ｅ B ｅ It consists of N, where d is between 0.20 and 0.99, and e is greater than 0 and less than or equal to 0.05.

[0092] The cutting tool of Embodiment 2 can have basically the same configuration as the cutting tool of Embodiment 1, except for the configuration of layers A, B, and C. The differences from the cutting tool of Embodiment 1 will be described below.

[0093] <Coating> As shown in Figures 6 and 7, the coating 3 includes layer A 13A, and layer A 13A may be provided directly on the substrate 2.

[0094] The coating 3 may include other layers in addition to layer A 13A. As shown in Figures 8 to 9, the coating 3 may include layer B 16B, which is placed between the substrate 2 and layer A 13A. As shown in Figures 6 to 9, the coating 3 may include layer C 14C, which is provided on the side of layer A 13A opposite to the substrate 2.

[0095] <Layer A> In the cutting tool of Embodiment 2, Layer A consists of alternating layers in which a first unit layer and a third unit layer are stacked alternately. The thickness of Layer A can be the same as the thickness of the first layer described in Embodiment 1. Either the first unit layer or the third unit layer may be positioned closest to the substrate. The first unit layer may have a cubic crystal structure. The third unit layer may have a cubic crystal structure.

[0096] <Composition of the first unit layer and the third unit layer> Composition of the first unit layer Ti of Embodiment 2 １－ａ－ｂ Al ａ Sc ｂ N is the composition Ti of the first unit layer in Embodiment 1. １－ａ－ｂ Al ａ Sc ｂ It can be considered identical to N.

[0097] The third unit layer is Ti ｄ Si １－ｄ－ｅ B ｅ It consists of N, where d is between 0.20 and 0.99, and e is greater than 0 and less than or equal to 0.05.

[0098] d is between 0.20 and 0.99. d may also be between 0.25 and 0.95, or between 0.30 and 0.90.

[0099] e is greater than 0 and less than or equal to 0.05. This improves the hardness and oxidation resistance of layer A. e may also be between 0.01 and 0.05, between 0.02 and 0.05, between 0.02 and 0.04, or between 0.02 and 0.03.

[0100] In this disclosure, "The third unit layer is Ti ｄ Si １－ｄ－ｅ B ｅ"Consists of N" means that, insofar as it does not impair the effects of this disclosure, the third unit layer is Ti ｄ Si １－ｄ－ｅ B ｅ This means that in addition to N, unavoidable impurities may be included. Examples of such unavoidable impurities include oxygen and carbon. The total content of unavoidable impurities in the third unit layer may be greater than 0 atomic percent and less than 1 atomic percent.

[0101] In this disclosure, the composition Ti of the third unit layer ｄ Si １－ｄ－ｅ B ｅ In N, the total number of atoms of Ti, Si, and M is A. Ｍ３ Number of atoms A in N Ｎ３ Ratio A Ｎ３ / A Ｍ３ The ratio is between 0.8 and 1.2. Ｎ３ / A Ｍ３ This can be measured by the Rutherford backscattering (RBS) method. Ratio A Ｎ１ / A Ｍ１ The ratio is 0.8 or more and 1.2 or less, and ratio A Ｎ３ / A Ｍ３ It has been confirmed that the effects of this disclosure will not be impaired if the scope is as described above.

[0102] <Average thickness of the first unit layer and the average thickness of the third unit layer> The average thickness of the first unit layer may be 2 nm or more and 200 nm or less, and the average thickness of the third unit layer may be 2 nm or more and 200 nm or less. The average thickness of the first unit layer may be 5 nm or more and 150 nm or less, or 10 nm or more and 100 nm or less. The average thickness of the third unit layer may be 5 nm or more and 150 nm or less, or 10 nm or more and 100 nm or less.

[0103] The average thickness of the first unit layer and the average thickness of the third unit layer are measured by the same method as the method for measuring the thickness of the first layer described above.

[0104] As shown in Figure 10, in the first unit layer 12 and the third unit layer 17 adjacent to the first unit layer 12, the ratio λ1 / λ3 of the thickness of the first unit layer 12 to the thickness λ3 (nm) of the third unit layer 17 may be 1 or more and 5 or less, 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.

[0105] In Figure 10, for illustrative purposes, the thickness of all first unit layers 12 is shown as λ1 and the thickness of all third unit layers 17 is shown as λ3. However, as long as the above 1 / λ3 relationship is satisfied between adjacent first and third unit layers, the thickness λ1 of all first unit layers 12 does not need to be the same, nor does the thickness λ3 of all third unit layers 17 need to be the same.

[0106] In layer A, the number of layers of the first unit layer and the third unit layer may be 5 to 500, 10 to 500, 100 to 400, or 200 to 350. By laminating the first unit layer and the third unit layer, it is possible to fully obtain the effect of improving the hardness, oxidation resistance, wear resistance, heat resistance, and chipping resistance of layer A in a well-balanced manner.

[0107] <Layer B> In the cutting tool of Embodiment 2, the coating may further include a Layer B disposed between the substrate and Layer A. The composition of Layer B may be the same as the composition of either the first unit layer or the third unit layer. Layer B may be placed directly on top of the substrate.

[0108] The effects and thickness of layer B when the composition of layer B is the same as the composition of the first unit layer are as described in Embodiment 1.

[0109] When the composition of layer B is the same as that of the third unit layer, the second unit layer tends to have a large compressive residual stress. Therefore, the coating's resistance to chipping can be improved, especially in intermittent machining where repeated loads are applied to the cutting edge.

[0110] If the composition of layer B is the same as the composition of the third unit layer, the thickness of layer B may be greater than the thickness of the third unit layer. This further improves the chipping resistance of the coating.

[0111] The thickness of layer B may be more than 1 times but 500 times or less than or equal to 2 times or 500 times or equal to 4 times or 120 times or equal to 10 times or equal to 50 times the thickness of the third unit layer.

[0112] If the composition of layer B is the same as the composition of the third unit layer, the thickness of layer B 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 1 μm or less. This makes it easier to obtain the above-mentioned effects by arranging layer B.

[0113] If the composition of layer B is the same as the composition of the third unit layer, the first unit layer 12 may be laminated directly on top of layer B 16B, as shown in Figure 8. Alternatively, the third unit layer 17 may be laminated directly on top of layer B 16B, as shown in Figure 9. When the composition of layer B is the same as the composition of the third unit layer, and the third unit layer is laminated directly on top of layer B, layer B and the third unit layer have a continuous crystalline structure.

[0114] <C layer> The C layer may have the same configuration and effects as the third layer described in Embodiment 1.

[0115] [Embodiment 3: Method for Manufacturing a Cutting Tool] Embodiment 3 describes a method for manufacturing a cutting tool according to Embodiment 1 or Embodiment 2. The method for manufacturing a cutting tool according to Embodiment 3 comprises 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 layer A. Details of each step are described below.

[0116] <Step 1> In Step 1, the substrate is prepared. The substrate can be the substrate described in Embodiment 1. Any conventionally known substrate can be prepared.

[0117] <Second Step> In the second step, a coating is formed on the substrate. The second step includes the step of forming the first layer or layer A.

[0118] In the process of forming the first layer, the first layer is formed by alternately stacking a first unit layer and a second unit layer using the Physical Vapor Deposition (PVD) method. In the process of forming layer A, layer A is formed by alternately stacking a first unit layer and a third unit layer using the PVD method. To improve the abrasion resistance of the coating including the first layer or layer A, it is effective to form a layer made of a highly crystalline compound. The inventors have found that by using the Physical Vapor Deposition method as a method for forming the first layer and layer A, a layer made of a highly crystalline compound can be formed, and the coating has excellent abrasion resistance.

[0119] As the PVD method, at least one selected from the group consisting of cathode arc ion plating, balanced magnetron sputtering, unbalanced magnetron sputtering, and HiPIMS (High Power Impulse Magnetron Sputtering) can be used. Cathode arc ion plating, which has a high ionization rate of the raw material elements, may also be used. When using cathode arc ion plating, it is possible to perform metal ion bombardment treatment on the surface of the substrate before forming the first layer or layer A, so that the adhesion between the substrate and the coating including the first layer or layer A is greatly improved.

[0120] Cathode arc ion plating can be performed, for example, by placing a substrate and a target as a cathode in the apparatus, then applying a high voltage to the target to generate an arc discharge, thereby ionizing and evaporating the atoms constituting the target, and depositing the material onto the substrate.

[0121] Balanced magnetron sputtering can be performed, for example, by placing a substrate in the 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 colliding the gas ions generated by this gas plasma with the target to deposit the atoms emitted from the target onto the substrate.

[0122] Unbalanced magnetron sputtering can be performed, for example, by making the magnetic field generated by the magnetron electrode in the balanced magnetron sputtering method described above unbalanced. Furthermore, the HiPIMS method, which allows for the application of higher voltages and the acquisition of denser films, can also be used.

[0123] <Other Processes> In addition to the process of forming the first layer or layer A, the second process may include surface treatment processes for the coating, such as polishing with a brush or dry or wet shot blasting. The second process may also include processes for forming other layers, such as the second layer, third layer, layer B, and layer C. These other layers can be formed by conventionally known chemical vapor deposition or physical vapor deposition methods. From the viewpoint of being able to form the other layers continuously with the first layer or layer A within a single physical vapor deposition apparatus, it is preferable to form the other layers by physical vapor deposition.

[0124] This embodiment will be described in more detail by reference to examples. However, this embodiment is not limited by these examples.

[0125] [Example 1] <Samples 1 to 18, Samples 101 to 109> <Preparation of cutting tools> Figure 11 is a schematic cross-sectional view of the cathode arc ion plating apparatus used in Example 1, and Figure 12 is a schematic top view of the apparatus in Figure 11.

[0126] In the apparatus shown in Figures 11 and 12, a cathode 106 for the first unit layer, a cathode 107 for the second unit layer, and a cathode 120 for the third layer, which are alloy targets that serve as the metal raw material for the coating, are installed in the chamber 101, along with a rotatable substrate holder 104 for setting the substrate. Cathode 106 is made of Ti, Al, and Sc, and the ratio of each element is adjusted to obtain the composition of the first unit layer shown in Table 1. Cathode 107 is made of Ti and Si, and the ratio of each element is adjusted to obtain the composition of the second unit layer shown in Table 1. Cathode 120 is made of Ti.

[0127] 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 the substrate holder 104. A gas inlet 105 into which gas 102 is introduced is provided inside the chamber 101, and a gas outlet 103 is provided to adjust the pressure inside the chamber 101, and the structure is such that gas 102 inside the chamber 101 can be sucked out from the gas outlet 103 by a vacuum pump.

[0128] A chip made of cemented carbide with a grade of JIS standard K20, specifically SEMT13T3AGSN manufactured by Sumitomo Electric Hardmetal Co., Ltd., was mounted on the base material holder 104.

[0129] Next, the pressure inside the chamber 101 is reduced by a vacuum pump, and the substrate is heated to 600°C by a heater installed in the apparatus while rotating, so that the pressure inside the chamber 101 is 1.0 × 10⁻⁶. －４ Vacuum was applied until the pressure reached Pa. Next, argon gas was introduced through the gas inlet to maintain the pressure inside chamber 101 at 2.0 Pa, and the voltage of the bias power supply 110 was gradually increased to -1000 V, while the surface of the substrate was cleaned for 15 minutes. After that, the substrate was cleaned by exhausting the argon gas from inside chamber 101 (argon bombardment). The substrates for the cutting tools of each sample were prepared in this manner.

[0130] Next, with the substrate rotating in the center, nitrogen was introduced as the reaction gas, and while maintaining the substrate temperature at 500°C, the reaction 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 120A was supplied to cathodes 106 and 107, respectively, thereby generating metal ions from cathodes 106 and 107 and forming a second layer having the composition shown in Table 2 and a first layer having the composition shown in Table 1 on the substrate.

[0131] If the second layer is formed, the first layer is formed by alternately stacking the first unit layer and the second unit layer one layer at a time on the second layer, according to the number of layers shown in Table 1. If the second layer is not formed, the first layer is formed by alternately stacking the first unit layer and the second unit layer one layer at a time on the substrate, according to the number of layers shown in Table 1.

[0132] The thickness of the second layer, the thickness of the first and second unit layers within the first layer, and the number of layers were adjusted by the rotation speed of the substrate. The current supplied to the evaporation source was stopped when the thicknesses of the second and first layers reached the thicknesses shown in Tables 1 and 2, respectively. A "-" in the "Second Layer" column of Table 2 indicates that the second layer does not exist.

[0133] Next, while introducing nitrogen gas and methane gas as reaction gases into the chamber 101, and maintaining the substrate temperature at 400°C, the reaction gas pressure at 2.0 Pa, and the bias power supply voltage at -300 V, an arc current of 100 A was supplied to the cathode 120 to generate metal ions from the cathode 120 and form a third layer on the first layer. When the thickness of the third layer reached the thickness shown in Table 2, the current supplied to the evaporation source was stopped. Cutting tools for each sample were then fabricated. The "-" in the "Third Layer" column of Table 2 indicates that the third layer is absent.

[0134]

[0135]

[0136] ≪Evaluation≫ For each cutting tool sample, the composition of the first unit layer, second unit layer, second layer, and third layer, the number of layers of the first and second unit layers, 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, and λ1 / λ2 were measured using the method described in Embodiment 1. The results are shown in Tables 1 and 2.

[0137] If "TiAlScCN" is written in the third layer, the atomic ratio of Ti, Al, and Sc in the third layer is the same as the atomic ratio of Ti, Al, and Sc in the first unit layer. A stacking count of 10 indicates that the alternating layers consist of 10 first unit layers and 10 second unit layers. If "-" is written in the "λ1 / λ2" column, it means that at least one of the first or second unit layers is absent.

[0138] For samples 1 to 18, the crystal structure of the first and second unit layers was confirmed by performing XRD measurements on the first unit layer of the cutting tool for each sample. The specific method is as described in Embodiment 1. In these samples, it was confirmed that the first unit layer had a cubic crystal structure and the second unit layer had a cubic crystal structure.

[0139] The hardness of the coatings in samples 1 to 18 was measured using the method described in Embodiment 1. It was confirmed that the hardness of the coatings in these samples was within the range of 30 GPa to 55 GPa.

[0140] In samples 1 to 18, the compressive residual stress of the coating was measured using the method described in Embodiment 1. It was confirmed that the absolute values ​​of the compressive residual stress of the coatings in these samples were 6 GPa or less.

[0141] <Cutting Test 1: Milling Test> For each sample of SEMT13T3AGSN shaped cutting tool, the center line of a 150 mm wide plate was aligned with the center of a wider φ160 mm cutter, and surface milling was performed under the following cutting conditions. The cutting length until the wear on the flank surface of the cutting edge reached 0.2 mm was measured. The results are shown in Table 2. A longer cutting length indicates a longer tool life. <Cutting Conditions> ・Workpiece material: FCD700 (HB250) ・Cutting speed: 230 m / min ・Feed rate: 0.3 mm / t ・Axial depth of cut ap: 2.0 mm ・Radial depth of cut ae: 150 mm ・Dry cutting The cutting process performed under the above cutting conditions corresponds to a cutting process performed under conditions where the cutting edge temperature is high.

[0142] The cutting tools of Samples 1 to 18 correspond to the examples, while the cutting tools of Samples 101 to 109 correspond to the comparative examples. It was confirmed that the cutting tools of Samples 1 to 18 have a longer tool life compared to the cutting tools of Samples 101 to 109 when performing cutting operations under conditions where the cutting edge temperature is high.

[0143] [Example 2] <Samples 21 to 38, Samples 121 to 129> A coating was formed on a substrate using the same cathode arc ion plating apparatus as in Example 1. Cathode 106 consists of Ti, Al, and Sc, and the ratio of each element is adjusted to obtain the composition of the first unit layer shown in Tables 3 and 4. Cathode 107 consists of Ti, Si, and B, and the ratio of each element is adjusted to obtain the composition of the third unit layer shown in Table 3. The composition of cathode 120 is Ti.

[0144] A chip made of SEMT13T3AGSN, a cemented carbide alloy manufactured by Sumitomo Electric Hardmetal Co., Ltd., with a grade of JIS standard K20, was mounted on the base material holder 104, and the base material was prepared by cleaning it in the same manner as in Example 1.

[0145] Next, layers B and C having the compositions shown in Table 4, and layer A having the composition shown in Table 3 were formed on the substrate under the same conditions as in Example 1, to obtain cutting tools for each sample.

[0146]

[0147]

[0148] ≪Evaluation≫ For each cutting tool sample, the composition of the first unit layer, third unit layer, B layer, and C layer, the number of layers of the first and third unit layers respectively, the average thickness of the first unit layer, the average thickness of the third unit layer, the thickness of the A layer, the B layer, the C layer, and λ1 / λ3 were measured using the same method as in Example 1. The results are shown in Tables 3 and 4.

[0149] In samples 21 to 38, it was confirmed that the first and second unit layers have a cubic crystal structure. The hardness of the coatings in samples 21 to 38 was confirmed to be within the range of 30 GPa to 55 GPa. The absolute value of the compressive residual stress of the coatings in samples 21 to 38 was confirmed to be 6 GPa or less.

[0150] <Cutting Test 2: Milling Test> For each sample of SEMT13T3AGSN shaped cutting tool, the center line of a 150 mm wide plate was aligned with the center of a wider φ160 mm cutter, and surface milling was performed under the following cutting conditions. The cutting length until the wear on the flank surface of the cutting edge reached 0.2 mm was measured. The results are shown in Table 4. A longer cutting length indicates a longer tool life. <Cutting Conditions> ・Workpiece material: SKD11 (HB250) ・Cutting speed: 220 m / min ・Feed rate: 0.25 mm / t ・Axial depth of cut ap: 2.0 mm ・Radial depth of cut ae: 150 mm ・Dry cutting The cutting process performed under the above cutting conditions corresponds to a cutting process performed under conditions where the cutting edge temperature is high.

[0151] The cutting tools of samples 21 to 38 correspond to the examples, while the cutting tools of samples 121 to 129 correspond to the comparative examples. It was confirmed that the cutting tools of samples 21 to 38 have a longer tool life compared to the cutting tools of samples 121 to 129 when performing cutting operations under conditions where the cutting edge temperature is high.

[0152] While embodiments and examples of this disclosure have been described above, it is intended from the outset that the configurations of each of the embodiments and examples described above may be combined or modified in various ways as appropriate. The embodiments and examples disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the embodiments and examples described above, and all modifications within the scope of the claims are intended to be included in the meaning of equivalences.

[0153] 1 Cutting tool, 2 Substrate, 3 Coating, 12 First unit layer, 13 First layer, 13A Layer A, 14 Third layer, 14C Layer C, 15 Second unit layer, 16 Second layer, 16B Layer B, 17 Third unit layer, 101 Chamber, 102 Gas, 103 Gas outlet, 104 Substrate holder, 105 Gas inlet, 106, 107, 120 Cathode, 108, 109 Arc power supply, 110 Bias power supply.

Claims

1. A cutting tool comprising a base material and a coating disposed on the base material, wherein the coating includes a first layer, the first layer consists of alternating layers in which a first unit layer and a second unit layer are alternately stacked, and the first unit layer is made of Ti １－ａ－ｂ Al ａ Sc ｂ It consists of N, where a is 0.350 or more and 0.650 or less, where b is 0.010 or more and 0.100 or less, and the second unit layer is Ti ｃ Si １－ｃ A cutting tool comprising N, wherein c is 0.20 or more and 0.99 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 λ1 / λ2 of the thickness of the first unit layer to the thickness λ2 of the second unit layer is 1 or more and 5 or less.

3. The cutting tool according to claim 1 or claim 2, wherein the average thickness of the first unit layer is 2 nm or more and 200 nm or less, and the average thickness of the second unit layer is 2 nm or more and 200 nm or less.

4. The cutting tool according to any one of claims 1 to 3, wherein the coating further comprises a second layer disposed between the substrate and the first layer, the composition of the second layer being the same as the composition of either the first unit layer or the second unit layer, the thickness of the second layer being greater than the average thickness of the unit layers having the same composition, and the thickness of the second layer being 0.1 μm or more and 1.0 μm or less.

5. The cutting tool according to any one of claims 1 to 4, wherein the coating further comprises a third layer provided on the side of the first layer opposite to the substrate, the third layer being made of TiCN or TiAlScCN, and the thickness of the third layer being 0.1 μm or more and 1.0 μm or less.

6. The cutting tool according to any one of claims 1 to 5, wherein the thickness of the first layer is 0.5 μm or more and 15 μm or less.

7. A cutting tool comprising a substrate and a coating disposed on the substrate, wherein the coating includes an A layer, the A layer is composed of an alternating layer in which a first unit layer and a third unit layer are alternately laminated, the first unit layer is composed of Ti １－ａ－ｂ Al ａ Sc ｂ N, where a is 0.350 or more and 0.650 or less, b is 0.010 or more and 0.100 or less, the third unit layer is composed of Ti ｄ Si １－ｄ－ｅ B ｅ N, where d is 0.20 or more and 0.99 or less, e is more than 0 and 0.05 or less.

8. The cutting tool according to claim 7, wherein in the first unit layer and the third unit layer adjacent to the first unit layer, the ratio λ1 / λ3 of the thickness of the first unit layer to the thickness λ3 of the third unit layer is 1 or more and 5 or less.

9. The cutting tool according to claim 7 or claim 8, wherein the average thickness of the first unit layer is 2 nm or more and 200 nm or less, and the average thickness of the third unit layer is 2 nm or more and 200 nm or less.

10. The cutting tool according to any one of claims 7 to 9, wherein the coating further comprises a B layer disposed between the substrate and the A layer, the composition of the B layer is the same as the composition of either the first unit layer or the third unit layer, the thickness of the B layer is greater than the average thickness of the unit layers having the same composition, and the thickness of the B layer is 0.1 μm or more and 1 μm or less.

11. The cutting tool according to any one of claims 7 to 10, wherein the coating further comprises a C layer provided on the side of the A layer opposite to the substrate, the C layer being made of TiCN or TiAlScCN, and the thickness of the C layer being 0.1 μm or more and 1.0 μm or less.

12. The cutting tool according to any one of claims 7 to 11, wherein the thickness of the A layer is 0.5 μm or more and 15 μm or less.

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