Cutting tool

Abstract

This cutting tool comprises a base material and a coating disposed on the base material, wherein: the coating includes an α-Al2O3 layer disposed on the base material and a TiCxNy layer disposed on the α-Al2O3 layer; x and y satisfy the relations represented by expression 1 and expression 2; the TiCxNy layer comprises a plurality of TiCxNy crystals; the TiCxNy crystals are columnar and extend along a direction from the base material toward the surface of the coating; and the crystal diameter of the TiCxNy crystals is 0.05-0.5 μm.

Description

Cutting tool

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

[0002] Conventionally, a cutting tool including a base material and a coating disposed on the base material, the coating being α-Al ２ O ３ layer, and a TiCN layer or a TiCNO layer disposed on the α-Al ２ O ３ layer, has been used in cutting (Patent Documents 1 and 2).

[0003] Japanese Patent Application Laid-Open No. 2020-116645, Japanese Patent Application Laid-Open No. 2020-116646

[0004] The cutting tool of the present disclosure is a cutting tool including a base material and a coating disposed on the base material, the coating being α-Al ２ O ３ layer, and a TiC ２ O ３ layer disposed on the α-Al ｘ N ｙ layer, where x and y satisfy the relationships of Formula 1 and Formula 2, 0.7 ≦ x + y ≦ 1.3 Formula 1 y ≧ 1.5x Formula 2 The TiC ｘ N ｙ layer is composed of a plurality of TiC ｘ N ｙ crystals, and the TiC ｘ N ｙ crystals are columnar crystals extending along the direction from the base material to the surface of the coating, and the crystal diameter of the TiC ｘ N ｙ crystals is 0.05 μm or more and 0.5 μm or less.

[0005] FIG. 1 is a schematic diagram showing an example of a cross-section of a cutting tool according to Embodiment 1. FIG. 2 is a schematic diagram showing another example of a cross-section of a cutting tool according to Embodiment 1. FIG. 3 is a schematic diagram showing another example of a cross-section of a cutting tool according to Embodiment 1. FIG. 4 is a schematic cross-sectional view of an example of a CVD (Chemical Vapor Deposition) apparatus used for manufacturing the cutting tool of the present disclosure.

[0006] [Problems this disclosure aims to solve] In recent years, the load on the cutting edge of cutting tools has tended to increase due to the increasing difficulty of machining workpieces. As a result, the demand for improved cutting tool characteristics is increasing. This is also true for cutting tools used in cast iron machining. A cutting tool comprising a base material and a coating disposed on the base material, wherein the coating is α-Al disposed on the base material ２ O ３ The layer and the α-Al ２ O ３ When cutting tools containing a TiCN layer or TiCNO layer arranged on a layer (Patent Documents 1-2) are used in cast iron machining, the tool life is sometimes insufficient. As a result, such cutting tools have difficulty exhibiting excellent tool life, especially in cast iron machining. Therefore, especially in cast iron machining, there is a need to provide excellent tool life by giving cutting tools superior "wear resistance".

[0007] Therefore, this disclosure aims to provide a cutting tool that has excellent tool life, particularly in the machining of cast iron.

[0008] [Effects of this disclosure] According to this disclosure, it is possible to provide cutting tools with excellent tool life, especially in the machining of cast iron.

[0009] [Description of Embodiments of the Disclosure] First, embodiments of the Disclosure will be listed and described. (1) A cutting tool of the Disclosure comprising a base material and a coating disposed on the base material, wherein the coating is α-Al disposed on the base material ２ O ３ The layer and the α-Al ２ O ３ TiC arranged in layers ｘ N ｙ The TiC includes a layer, and x and y satisfy the relationship between Equations 1 and 2: 0.7 ≤ x + y ≤ 1.3 Equation 1 y ≥ 1.5x Equation 2 The TiC ｘ N ｙ The layer consists of multiple TiC ｘ N ｙ Composed of crystals, the TiC ｘ N ｙThe crystals are columnar crystals that extend along the direction from the substrate to the surface of the coating, and the TiC ｘ N ｙ The crystal diameter is between 0.05 μm and 0.5 μm.

[0010] According to this disclosure, it is possible to provide cutting tools with excellent tool life, especially in the machining of cast iron.

[0011] (2) In the above (1), the TiC ｘ N ｙ The aspect ratio of the crystal may be between 10 and 30. This makes it possible to provide cutting tools with superior tool life, especially in the machining of cast iron.

[0012] (3) In (1) or (2) above, the TiC ｘ N ｙ The layer thickness may be between 0.5 μm and 5 μm. This makes it possible to provide cutting tools with superior tool life, especially in the machining of cast iron.

[0013] (4) In any of (1) to (3) above, the α-Al ２ O ３ The layer consists of multiple α-Al ２ O ３ It consists of particles, and the α-Al ２ O ３ The particle size may be between 0.3 μm and 1.0 μm. This makes it possible to provide cutting tools with superior tool life, especially in the machining of cast iron.

[0014] (5) In any of (1) to (4) above, the coating is the α-Al ２ O ３ Layer and the TiC ｘ N ｙ Between the layers, the α-Al ２ O ３ Layer and the TiC ｘ N ｙThe material further includes a TiCNO layer positioned in contact with the layer, and the thickness of the TiCNO layer may be 1 μm or less. This makes it possible to provide a cutting tool with superior tool life, especially in the machining of cast iron.

[0015] (6) In any of (1) to (5) above, the coating is the TiC ｘ N ｙ The material may further include a TiN layer placed in contact with the layer. This makes it possible to provide a cutting tool with better tool life, especially in the machining of cast iron.

[0016] (7) In any of (1) to (6) above, x and y may further satisfy the relationship in Equation 3: y > 1.5x Equation 3 This makes it possible to provide cutting tools with better tool life, especially in the machining of cast iron.

[0017] [Details of Embodiments of the Disclosure] A specific example of a cutting tool according to one embodiment of the Disclosure (hereinafter also referred to as "this embodiment") will be described below with reference to the drawings. In the drawings of the Disclosure, the same reference numerals represent the same part or a corresponding part. In addition, 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.

[0018] In this disclosure, the notation "A to B" means an upper and lower limit of the range (i.e., A or greater and B or less), and if no unit is specified for A, but a unit is specified only for B, then the unit for A and the unit for B are the same.

[0019] 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.

[0020] [Embodiment 1: Cutting Tool] A cutting tool according to one embodiment of the present disclosure will be described with reference to Figures 1 to 3. Figure 1 is a schematic cross-sectional view illustrating one aspect of the cutting tool of the present disclosure. Figure 2 is a schematic cross-sectional view illustrating another aspect of the cutting tool of the present disclosure. Figure 3 is a schematic diagram showing yet another example of a cross-section of the cutting tool according to Embodiment 1. One embodiment of the present disclosure (hereinafter also referred to as "this embodiment") is a cutting tool 10 comprising a base material 1 and a coating 2 disposed on the base material 1, wherein the coating 2 is α-Al disposed on the base material 1 ２ O ３ Layer 3 and the α-Al ２ O ３ TiC placed on layer 3 ｘ N ｙ Layer 4 and the TiC include, where x and y satisfy the relationship between Equation 1 and Equation 2, 0.7 ≤ x + y ≤ 1.3 Equation 1 y ≥ 1.5x Equation 2 the TiC ｘ N ｙ Layer 4 consists of multiple TiC ｘ N ｙ It consists of crystals, and the TiC ｘ N ｙ The crystals are columnar crystals that extend along the direction from the substrate 1 to the surface of the coating 2, and the TiC ｘ N ｙ The crystal diameter is between 0.05 μm and 0.5 μm.

[0021] According to this disclosure, a cutting tool 10 with excellent tool life can be provided, particularly in the machining of cast iron. The reason for this is presumed to be as follows.

[0022] In the cutting tool 10 of this embodiment, the coating 2 is α-Al disposed on the base material 1. ２ O ３ Layer 3 and the α-Al ２ O ３ TiC placed on layer 3 ｘ N ｙ Layer 4 and, including, x and y satisfy the relationship between the above formulas 1 and 2, the TiC ｘ N ｙ Layer 4 consists of multiple TiC ｘ N ｙ It consists of crystals, and the TiC ｘ N ｙThe crystals are columnar crystals that extend along the direction from the substrate 1 to the surface of the coating 2, and the TiC ｘ N ｙ The crystal diameter is 0.05 μm or more and 0.5 μm or less. ｘ N ｙ In layer 4, the total amount of carbon atoms contributing to hardness and nitrogen atoms contributing to toughness increases, and the amount of nitrogen atoms is sufficiently greater than the amount of carbon atoms. Furthermore, the expansion of minute chipping is easily suppressed, thus improving both the hardness and toughness of the coating. The excellent hardness and toughness of the coating contribute to excellent tool life, especially in cast iron machining. Therefore, the cutting tool 10 of this embodiment can exhibit excellent tool life, especially when used in cast iron machining.

[0023] ≪Cutting Tool≫ As shown in Figures 1 to 3, a cutting tool 10 according to one embodiment of the present disclosure comprises a base material 1 and a coating 2 disposed on the base material 1. Preferably, the coating 2 covers the entire surface of the base material 1, but even if a part of the base material 1 is not covered by the coating 2, or if the configuration of the coating 2 is partially different, it does not depart from the scope of this embodiment. If a part of the base material 1 is not covered by the coating 2, it is preferable that the coating 2 is arranged to cover at least the surface of the portion of the base material 1 that is involved in cutting. In this specification, the portion of the base material 1 that is involved in cutting means, depending on the size and shape of the base material 1, the area of ​​the base material 1 enclosed by its cutting edge and a hypothetical surface whose distance from the cutting edge towards the base material 1 along the perpendicular to the tangent to the cutting edge is, for example, 5 mm, 3 mm, 2 mm, 1 mm, or 0.5 mm.

[0024] The cutting tool 10 of this embodiment can be suitably used as a cutting tool 10 such as a drill, end mill, replaceable cutting tip for drills, replaceable cutting tip for end mills, replaceable cutting tip for milling, replaceable cutting tip for turning, metal saw, gear cutting tool, reamer, tap, etc.

[0025] <<Substrate>> The cutting tool 10 includes a substrate 1. As the substrate 1, any conventionally known substrate of this kind can be used. For example, cemented carbide (WC-based cemented carbide, cemented carbide containing WC and Co, further cemented carbide added with carbonitrides such as Ti, Ta, Nb, etc.), cermet (the one with TiC, TiN, TiCN, etc. as the main components), high-speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, etc.), cubic boron nitride sintered body, or diamond sintered body is preferably used.

[0026] Among these various substrates 1, it is particularly preferable to select WC-based cemented carbide and cermet (especially TiCN-based cermet). These substrates 1 are particularly excellent in the balance between hardness and strength at high temperatures, and can contribute to extending the life of the cutting tool 10 when used as the substrate 1 of the cutting tool 10.

[0027] <<Coating>> The cutting tool 10 includes a coating 2 disposed on the substrate 1. The coating 2 includes an α-Al ２ O ３ layer 3 and a TiC ２ N ３ layer 4 disposed on the α-Al ｘ N ｙ layer 4. The coating 2 may further include a TiCNO layer 5 disposed between the α-Al ２ O ３ layer 3 and the TiC ｘ N ｙ layer 4 and in contact with the α-Al ２ O ３ layer 3 and the TiC ｘ N ｙ layer 4. As a result, since the TiCNO layer 5 has excellent adhesion to the α-Al ２ O ３ layer 3 and the TiC ｘ N ｙ layer 4, it is possible to provide a cutting tool 10 having a more excellent tool life, especially in cast iron machining. The coating 2 is TiC ｘ N ｙThe coating may further include a TiN layer 6 positioned in contact with layer 4. This improves the identification of used corners, thereby suppressing the reduction in tool life caused by chipping due to welding with the TiN layer 6. Therefore, a cutting tool 10 with superior tool life can be provided, especially in cast iron machining. The coating 2 is α-Al ２ O ３ Layer 3 and TiC ｘ N ｙ It may consist of four layers, α-Al ２ O ３ Layer 3 and TiC ｘ N ｙ Layer 4 may consist only of one or both of TiCNO layer 5 and TiN layer 6, and to the extent that the effects of this disclosure are not impaired, α-Al ２ O ３ Layer 3, TiC ｘ N ｙ The system may further include layers other than layer 4, TiCNO layer 5, and TiN layer 6 (referred to as "other layers" later).

[0028] The thickness of the coating 2 may be 5 μm or more and 25 μm or less, or 7 μm or more and 20 μm or less. If the thickness of the coating 2 is less than 5 μm, the lifespan of the cutting tool 10 tends to be shortened due to the coating 2 being too thin. On the other hand, if the thickness of the coating 2 is greater than 25 μm, chipping of the coating 2 tends to occur in the initial stages of cutting, which tends to shorten the lifespan of the cutting tool 10.

[0029] The thickness of the coating 2 can be measured by observing a cross-section of the coating 2 along the normal direction of the surface of the coating 2 using a scanning electron microscope (SEM). Specifically, the observation magnification of the cross-sectional sample is set to 5,000 to 10,000 times, and the observation area is set to 100 to 500 μm². ２ To determine the thickness, we measure the thickness at any three points within any given field of view, and take the average (arithmetic mean) of these measurements as the "thickness." The same method is used for determining the thickness of each layer, as described later, unless otherwise specified.

[0030] ≪α-Al ２ O ３ Layer ≫ <α-Al ２ O ３ Layer composition > α-Al２ O ３ Layer 3 consists of multiple α-Al ２ O ３ It may consist of particles. In this disclosure, "α-Al ２ O ３ "Composed of particles" means α-Al ２ O ３ It may consist only of particles, and to the extent that it does not impair the effects of the present disclosure, α-Al ２ O ３ This means that in addition to particles, unavoidable impurities may be present. Examples of such unavoidable impurities include chlorine (Cl). α-Al ２ O ３ The total content of unavoidable impurities in layer 3 may be, for example, 0% by mass or more and 3% by mass or less, or 0% by mass or more and 1% by mass or less.

[0031] α-Al ２ O ３ α-Al in layer 3 ２ O ３ The particle content is determined by X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDX). α-Al ２ O ３ The content of unavoidable impurities in layer 3 is measured by secondary ion mass spectrometry (SIMS). ２ O ３ As long as measurements are taken at layer 3, it has been confirmed that there is almost no variation in the measurement results even if the measurement location is arbitrarily selected.

[0032] <α-Al ２ O ３ Particle>α-Al ２ O ３ The particle size may be between 0.3 μm and 1.0 μm. ２ O ３ Because the scale of particle shedding can be reduced, a cutting tool 10 with superior tool life can be provided, especially in the machining of cast iron. The particle size may be 0.4 μm or more and 0.9 μm or less, 0.45 μm or more and 0.85 μm or less, or 0.5 μm or more and 0.8 μm or less.

[0033] α-Al ２ O ３ The particle size can be measured using the following procedure (A1) to (A6).

[0034] (A1) Cut the cutting tool 10 along the normal of the rake face of the base material 1 with a diamond wire, α-Al ２ O ３ The cross-section of layer 3 is exposed. Ion milling is performed on the exposed cross-section using Ar ions to make the cross-section mirror-like. The conditions for the ion milling are as follows: • Acceleration voltage: 6kV • Irradiation angle: α-Al ２ O ３ α-Al in the cross-section of layer 3 ２ O ３ 0° from a straight line parallel to the thickness direction of layer 3; Irradiation time: 6 hours

[0035] (A2) The mirror-finished cross-section is observed at 5,000x magnification using an electrolytic emission scanning electron microscope (EF-SEM) to obtain a backscattered electron image (EBSD).

[0036] (A3) In the above EBSD, α-Al is present in the measurement range. ２ O ３ The interface of layer 3 near substrate 1 and α-Al ２ O ３ The measurement range is set so as to include the interface of layer 3 near the surface of film 2. The measurement range is a rectangle with dimensions of (horizontal direction (parallel to the surface of film 2): 30 μm) × (vertical direction (normal to the surface of film 2): length including the entire film 2).

[0037] (A4) Any one α-Al within the measurement range ２ O ３ For each particle, measure the lateral diameter at any three locations. By calculating the average (arithmetic mean) of the lateral diameters at any three locations, you can determine the size of any one α-Al ２ O ３ Determine the average lateral diameter of the particles.

[0038] (A5) Any 29 other α-Al within the measurement range ２ O ３ For each particle, determine the average transverse diameter using the same method as described in (A4) above.

[0039] (A6) Any 30 α-Al within the measurement range ２ O ３ For the particles, by calculating the average (arithmetic mean) of the average lateral diameter, α-Al ２ O ３ Identify the particle size.

[0040] Furthermore, the same α-Al ２ O ３ As long as measurements are taken on layer 3, it has been confirmed that there is almost no variation in the measurement results even when the measurement points are arbitrarily selected.

[0041] <α-Al ２ O ３ Layer thickness > α-Al ２ O ３ The thickness of layer 3 may be 4 μm or more and 15 μm or less. ２ O ３ Layer 3 has sufficient thickness to improve wear resistance, and α-Al ２ O ３ By moderately reducing the thickness of layer 3, sufficient chipping resistance can be achieved. α-Al ２ O ３ The thickness of layer 3 may be 5 μm or more and 10 μm or less, or 6 μm or more and 9 μm or less.

[0042] ≪TiC ｘ N ｙ Layer≫ <TiC ｘ N ｙ Layer composition > TiC ｘ N ｙ Layer 4 consists of multiple TiC ｘ N ｙ It consists of crystals. In this disclosure, "TiC ｘ N ｙ "Composed of crystals" refers to TiC ｘ N ｙ It may consist only of crystals, and to the extent that it does not impair the effects of this disclosure, TiC ｘ N ｙ This means that in addition to crystals, unavoidable impurities may be present. Examples of such unavoidable impurities include chlorine (Cl). (TiC) ｘ N ｙThe total content of unavoidable impurities in layer 4 may be, for example, 0% by mass or more and 0.10% by mass or less, or 0.01% by mass or more and 0.05% by mass or less.

[0043] TiC ｘ N ｙ TiC in layer 4 ｘ N ｙ The crystal content is determined by X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDX). TiC ｘ N ｙ The content of unavoidable impurities in layer 4 is measured by secondary ion mass spectrometry (SIMS). ｘ N ｙ As long as measurements are taken at layer 4, it has been confirmed that there is almost no variation in the measurement results even if the measurement location is arbitrarily selected.

[0044] The above x and y satisfy the relationship between Equation 1 and Equation 2. 0.7 ≤ x + y ≤ 1.3 Equation 1 y ≥ 1.5x Equation 2 This allows the ratio of Ti atoms to C atoms and N atoms to be within an appropriate range, and the ratio of N atoms contained in TiCN to be moderately high, thereby improving the balance of hardness and toughness of coating 2. The lower limit of x + y may be 0.8 or greater, or 0.9 or greater. The upper limit of x + y may be 1.2 or less, or 1.1 or less. The lower limit of the difference between 1.5x and y, 1.5x - y, may be -1 or greater, or -0.5 or greater. The upper limit of the difference between 1.5x and y, 1.5x - y, may be less than 0 (i.e., x and y may further satisfy the relationship in Equation 3). y > 1.5x Equation 3 This further improves the toughness of coating 2. The upper limit of the difference between 1.5x and y, 1.5x-y, may be -0.1 or less, -0.2 or less, or -0.3 or less. The lower limit of the difference between 1.5x and y, 1.5x-y, may be -1 or greater, or -0.5 or greater.

[0045] The above x may be between 0.2 and 0.4. This allows for a sufficient inclusion of C atoms, thereby improving the hardness compared to TiN, and thus further improving the hardness of coating 2. x may also be between 0.25 and 0.40, or between 0.25 and 0.35.

[0046] The above value of y may be between 0.5 and 0.9. This results in a composition that is superior in toughness compared to TiC, which is superior in hardness, and thus the toughness of the coating 2 can be further improved. The value of y may be between 0.6 and 0.85, or between 0.65 and 0.8.

[0047] The above x and y are measured by following the steps (B1) to (B2) below.

[0048] (B1) Cut the cutting tool 10 along the normal to the surface of the cutting tool 10 with a diamond wire, TiC ｘ N ｙ The cross-section of layer 4 is exposed. Focused ion beam processing (hereinafter also referred to as "FIB processing") is performed on the exposed cross-section to make the cross-section mirror-like.

[0049] (B2) TiC ｘ N ｙ In the cross-section of layer 4, rectangular analysis was performed using an energy-dispersive X-ray spectroscope (EDX) (TEM-EDX) attached to a transmission electron microscope (TEM), and TiC ｘ N ｙ Identify the composition of layer 4. Rectangular analysis is performed using TiC ｘ N ｙ The measurement is performed on three non-overlapping rectangular measurement areas of 0.5 μm × 2 μm set within the cross-section of layer 4. x' and y' are measured in each of the three measurement areas. The average of x' and the average of y' (arithmetic mean) of the three measurement areas are calculated. This average is then used to determine the TiC ｘ N ｙ This corresponds to x and y in layer 4.

[0050] It has been confirmed that, as long as measurements are taken on the same sample, there is almost no variation in the measurement results even when the selected area of ​​the measurement field is arbitrarily changed and measurements are taken multiple times.

[0051] <TiC ｘ N ｙ Crystal > TiC ｘ N ｙ The crystals are columnar crystals that extend along the direction from the substrate 1 to the surface of the coating 2. This makes it easier to suppress the propagation of cracks along the direction perpendicular to the normal direction of the surface of the coating 2, thereby improving the hardness of the coating 2. Note that "TiC" is used here. ｘ N ｙ The crystals are columnar crystals that extend along the direction from the substrate 1 to the surface of the coating 2." ｘ N ｙ This means the aspect ratio of the crystal is 2 or greater.

[0052] TiC ｘ N ｙ The aspect ratio of the crystal may be between 10 and 30. This allows for TiC ｘ N ｙ Because it is easier to suppress crystal shedding, a cutting tool 10 with superior tool life can be provided, especially in the machining of cast iron. ｘ N ｙ The aspect ratio of the crystal may be between 10 and 25, or between 10 and 20.

[0053] TiC ｘ N ｙ The aspect ratio of a crystal can be measured using the following procedure (C1) to (C5).

[0054] (C1) Cut the cutting tool 10 with a diamond wire along the normal to the surface of the cutting tool 10, TiC ｘ N ｙ The cross-section of layer 4 is exposed. FIB processing is performed on the exposed cross-section to make the cross-section mirror-finish.

[0055] (C2) EBSD analysis is performed on the FIB-processed cross section using a field emission scanning electron microscope (FE-SEM) equipped with an electron backscatter diffractometer (EBSD device) (product name: "SUPRA35VP", manufactured by Carl Zeiss) under the following measurement conditions. The area to be analyzed by EBSD (hereinafter also referred to as the analysis area) is TiC ｘ N ｙ The analysis area consists of three non-overlapping rectangular regions within layer 4. The size of the analysis area is a rectangle with a length of 20 μm or more in the direction parallel to the substrate 1. The length of the coating 2 in the thickness direction of the analysis area is TiC ｘ N ｙ The thickness of layer 4 can be set as appropriate. The length in the thickness direction of the coating 2 in the analysis area is, for example, TiC ｘ N ｙ Set so that the thickness of layer 4 is 90% or more. (Measurement conditions) Acceleration voltage: 15kV Current value: 1.8nA Irradiation current: 60μm (with HC) Exp: Long 0.03s Binning: 8×8 WD: 15mm Tilt: 70° Step size: 0.02μm BKD: Background Subtraction, Dynamic Background Subtraction, Normalize Intensity histogram Magnification: 20000x Grain boundary definition: 15° or more

[0056] (C3) For data collected by EBSD analysis, a cleanup process is performed by recognizing only data that satisfies CI > 0.1 using the CI Dilation method (single Interlation) and Grain CI Standardization. The CI value is calculated using the Voting method. Specifically, it is obtained by CI = (V1 - V2) / Videal (V1, 2: 1st and 2nd solutions, Videal: ideal solution).

[0057] (C4) The EBSD analysis results are analyzed using commercially available software (product name: "OIM7.1", manufactured by TSL Solutions Co., Ltd.) to create an IPF map (Inverse Pole Tigre map) of the analysis region. In creating the IPF map, a grain boundary is defined when the azimuthal difference angle between adjacent measurement points is 15° or more. The shape of each grain is shown in the IPF map.

[0058] (C5) Using the above software ("OMI7.1"), any 30 TiCs in the IPF map of each analysis region ｘ N ｙ The aspect ratio is measured for each crystal. (TiC) ｘ N ｙ The aspect ratio of a crystal is TiC ｘ N ｙ b / a is the ratio of the major axis a to the minor axis b of the crystal. In this disclosure, the major axis a is the TiC observed in the cross-section. ｘ N ｙ The maximum cross-section of the crystal, where the minor axis b is aligned with the direction perpendicular to the major axis a, and TiC ｘ N ｙ This is the maximum diameter of the crystal. In this disclosure, "TiC ｘ N ｙ The "crystal aspect ratio" is determined by a total of 30 TiC ｘ N ｙ This is the average (arithmetic mean) of the aspect ratios of the crystals. In this disclosure, TiC in the IPF map of the analysis region ｘ N ｙ Crystals are TiC ｘ N ｙ TiC crystals where all crystals are located within the IPF map of the analysis region ｘ N ｙ Crystals, and TiC ｘ N ｙ TiC crystals in which at least a portion of the crystal is present within the IPF map of the analysis region ｘ N ｙ It includes both crystalline and crystallized forms.

[0059] It has been confirmed that, as long as measurements are taken on the same sample, there is almost no variation in the measurement results even when the cutting position of the cutting tool 10 or the measurement area is changed and measurements are performed multiple times.

[0060] TiC ｘ N ｙ The crystal diameter is between 0.05 μm and 0.5 μm. ｘ N ｙ Because the crystals become finer, the hardness of the coating 2 can be improved. The crystal diameter may be 0.1 μm or more and 0.4 μm or less, 0.15 μm or more and 0.35 μm or less, or 0.2 μm or more and 0.3 μm or less.

[0061] TiC ｘ N ｙ The crystal diameter can be measured using the following procedure (D1) to (D6).

[0062] (D1) Cutting tool 10 along the normal of the rake face of base material 1 with a diamond wire, TiC ｘ N ｙ The cross-section of layer 4 is exposed. Ion milling is performed on the exposed cross-section using Ar ions to make the cross-section mirror-like. The conditions for the ion milling are as follows: • Acceleration voltage: 6kV • Irradiation angle: TiC ｘ N ｙ TiC in the cross-section of layer 4 ｘ N ｙ 0° from a straight line parallel to the thickness direction of layer 4; Irradiation time: 6 hours

[0063] (D2) The mirror-finished cross-section is observed at 5000x magnification using an electrolytic emission scanning electron microscope (EF-SEM) to obtain a backscattered electron image (EBSD).

[0064] (D3) In the above EBSD, TiC ｘ N ｙ The interface of layer 4 near substrate 1 and TiC ｘ N ｙ The measurement range is set so as to include the interface of layer 4 near the surface of the coating 2. The measurement range is a rectangle with dimensions of (horizontal direction (parallel to the surface of the coating 2): 30 μm) × (vertical direction (normal to the surface of the coating 2): length including the entire coating 2).

[0065] (D4) Any one TiC within the measurement range ｘ N ｙFor a crystal, measure the lateral diameter at any three locations. By calculating the average (arithmetic mean) of the lateral diameters at any three locations, you can determine the value of any one TiC crystal. ｘ N ｙ Determine the average lateral diameter of the crystal.

[0066] (D5) Any 29 other TiCs within the measurement range ｘ N ｙ For each crystal, the average lateral diameter is determined using the same method as described in (D4) above.

[0067] (D6) Any 30 TiCs within the measurement range ｘ N ｙ For crystals, the average (arithmetic mean) of the average lateral diameter can be calculated to determine TiC ｘ N ｙ Determine the crystal diameter of the crystal.

[0068] Note that the same TiC ｘ N ｙ As long as measurements are taken on layer 4, it has been confirmed that there is almost no variation in the measurement results even when the measurement points are arbitrarily selected.

[0069] <TiC ｘ N ｙ Layer hardness > TiC ｘ N ｙ The hardness of layer 4 may be 30 GPa or higher. This makes it possible to provide a cutting tool 10 with better tool life, especially in the machining of cast iron. TiC ｘ N ｙ The hardness of layer 4 may be 30 GPa or more and 40 GPa or less, 30 GPa or more and 35 GPa or less, or 31 GPa or more and 33 GPa or less.

[0070] TiC ｘ N ｙ The hardness of layer 4 is measured using a nanoindenter. Specifically, first, TiC ｘ N ｙ The hardness is measured for each of the 10 arbitrary points on the surface of layer 4. Here, TiC ｘ N ｙ If layer 4 is not the outermost surface, use mechanical polishing or similar methods to create a TiC ｘ Nｙ Layer 4 will be exposed and then measured with a nanoindenter. Next, the average (arithmetic mean) of the 10 hardness points obtained will be calculated as TiC ｘ N ｙ The hardness of layer 4 is used. An example of a nanoindenter is the ENT1100 (product name) manufactured by Elionix Co., Ltd. The measurement conditions are as follows.

[0071] (Measurement conditions for nanoindenter) Indenter: Berkovich load: 1 gf Loading time: 10 sec Holding time: 2 sec Unloading time: 10 sec

[0072] Note that the same TiC ｘ N ｙ As far as measurements of the layers are concerned, even when the selection of measurement points is changed and the measurement is performed multiple times, there is almost no variation in the measurement results, confirming that even if measurement points are set arbitrarily, the results are not arbitrary.

[0073] <TiC ｘ N ｙ Layer thickness > TiC ｘ N ｙ The thickness of layer 4 may be 0.5 μm or more and 5 μm or less. This allows TiC to be formed in the coating 2. ｘ N ｙ Because layer 4 (in other words, a layer with high hardness) is present with sufficient thickness, flank wear is more easily suppressed, and therefore, especially in the machining of cast iron, a cutting tool 10 with superior tool life can be provided. ｘ N ｙ The thickness of layer 4 may be 1 μm or more and 4 μm or less, or 1.5 μm or more and 3 μm or less.

[0074] <TiCNO Layer> <Composition of the TiCNO Layer> In this disclosure, TiCNO layer 5 means a layer made of TiCNO. Here, "made of TiCNO" means that it may consist only of TiCNO, and that in addition to TiCNO, unavoidable impurities may be included to the extent that the effects of this disclosure are not impaired. Examples of such unavoidable impurities include chlorine (Cl). The total content of unavoidable impurities in TiCNO layer 5 may be, for example, 0% by mass or more and 0.10% by mass or less, or 0.01% by mass or more and 0.05% by mass or less.

[0075] The TiCNO content in TiCNO layer 5 is determined by X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDX). The content of unavoidable impurities in TiCNO layer 5 is measured by secondary ion mass spectrometry (SIMS). It has been confirmed that there is almost no variation in the measurement results even if the measurement site is arbitrarily selected, as long as the measurement is performed on the same TiCNO layer 5.

[0076] <Thickness of TiCNO layer> The thickness of the TiCNO layer 5 may be 1 μm or less. ｘ N ｙ Because it becomes easier to suppress the peeling of layer 4 (in other words, the layer with high hardness), a cutting tool 10 with superior tool life can be provided, especially in the machining of cast iron. The thickness of the TiCNO layer 5 may be 0.3 μm or more and 1 μm or less, 0.4 μm or more and 0.9 μm or less, or 0.5 μm or more and 0.8 μm or less.

[0077] <TiN Layer> In this disclosure, TiN layer 6 means a layer made of TiN. Here, "made of TiN" means that it may consist only of TiN, and that in addition to TiN, unavoidable impurities may be included to the extent that they do not impair the effects of this disclosure. Examples of such unavoidable impurities include chlorine (Cl). The total content of unavoidable impurities in TiN layer 6 may be, for example, 0% by mass or more and 0.10% by mass or less, or 0.01% by mass or more and 0.05% by mass or less.

[0078] The TiN content in TiN layer 6 is determined by X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDX). The content of unavoidable impurities in TiN layer 6 is measured by secondary ion mass spectrometry (SIMS). It has been confirmed that, as long as measurements are taken in the same TiN layer 6, there is almost no variation in the measurement results even if the measurement site is arbitrarily selected.

[0079] <Thickness of TiN layer> The thickness of the TiN layer 6 is not particularly limited, but may be, for example, 1 μm or less. The thickness of the TiN layer 6 may be 0.3 μm or more and 1 μm or less, 0.3 μm or more and 0.9 μm or less, or 0.3 μm or more and 0.8 μm or less.

[0080] <<Other Layers>> Other layers include, for example, a base layer (not shown) and an intermediate layer (not shown). The base layer is the layer in contact with the substrate 1. The intermediate layer is the base layer and α-Al ２ O ３ A layer placed between layer 3, or if the TiCNO layer 5 is not present, then α-Al ２ O ３ Layer 3 and TiC ｘ N ｙ This is the layer that is placed between layer 4 and layer 4.

[0081] <Underlayer> The underlayer may consist of TiN or TiCN. "Consisting of TiN or TiCN" means that it may consist only of TiN or TiCN, or it may contain unavoidable impurities in addition to TiN or TiCN. Examples of unavoidable impurities include chlorine atoms (Cl), oxygen atoms (O), cobalt atoms (Co), tungsten atoms (W), nickel atoms (Ni), and boron atoms (B). The total content of unavoidable impurities in the underlayer may be, for example, 0% by mass or more and 1.0% by mass or less, or 0.3% by mass or more and 0.6% by mass or less.

[0082] The composition of the underlying layer as TiN or TiCN is determined by X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDX). The content of unavoidable impurities in the underlying layer is determined by secondary ion mass spectrometry (SIMS). It has been confirmed that, as long as measurements are taken on the same underlying layer, there is almost no variation in the measurement results even if the measurement location is arbitrarily selected.

[0083] The thickness of the underlayer may be 0.1 μm or more and 2.0 μm or less, 0.5 μm or more and 1.5 μm or less, or 0.8 μm or more and 1.3 μm or less.

[0084] <Intermediate Layer> The intermediate layer may consist of TiCN. "Consisting of TiCN" means that it may consist only of TiCN, or it may contain unavoidable impurities in addition to TiCN. Examples of unavoidable impurities include chlorine atoms (Cl), oxygen atoms (O), cobalt atoms (Co), tungsten atoms (W), nickel atoms (Ni), and boron atoms (B). The total content of unavoidable impurities in the intermediate layer may be, for example, 0% by mass or more and 1.0% by mass or less, or 0.3% by mass or more and 0.6% by mass or less.

[0085] The composition of the intermediate layer as TiCN is determined by X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX). The content of unavoidable impurities in the intermediate layer is determined by secondary ion mass spectrometry (SIMS). It has been confirmed that, as long as measurements are taken on the same intermediate layer, there is almost no variation in the measurement results even if the measurement site is arbitrarily selected.

[0086] The thickness of the intermediate layer may be 2.0 μm or more and 10 μm or less, or 4.0 μm or more and 8.0 μm or less.

[0087] [Embodiment 2: Method for Manufacturing Cutting Tools] The method for manufacturing cutting tools according to this embodiment will be described with reference to Figure 4. Figure 4 is a schematic cross-sectional view of an example of a CVD apparatus used in the manufacture of cutting tools according to this disclosure.

[0088] The method for manufacturing a cutting tool of this embodiment is the method for manufacturing a cutting tool described in Embodiment 1, comprising: a first step of preparing a base material 1; and a second step of forming a coating on the base material 1, wherein the second step is performed by CVD to produce α-Al ２ O ３ Step 2a involves forming a layer, and TiC by CVD. ｘ N ｙ The process includes a second b step for forming a layer, in this order. The second step may further include a second c step for forming a TiCNO layer by CVD between the second a step and the second b step. The second step may further include a second d step for forming a TiN layer by CVD after the second b step. Details of each step are described below.

[0089] <<First Step>> In the first step, the base material 1 is prepared. The base material 1 can be the base material 1 described in Embodiment 1.

[0090] For example, when using cemented carbide as the base material 1, a commercially available base material 1 may be used, or it may be manufactured by a general powder metallurgy method. When manufactured by a general powder metallurgy method, for example, WC powder and Co powder are mixed using a ball mill or the like to obtain a mixed powder. After drying the mixed powder, it is molded into a predetermined shape to obtain a molded body. Further sintering the molded body yields a WC-Co cemented carbide (sintered body). Next, by performing a predetermined cutting edge processing, such as honing, on the sintered body, a base material 1 made of WC-Co cemented carbide can be manufactured. Even if the base material 1 is not as described above, any conventionally known base material 1 of this type can be prepared.

[0091] ≪Second Step≫ In the second step, a coating is formed on the substrate 1 to obtain a cutting tool. The coating is formed using, for example, the CVD apparatus 30 shown in Figure 4. The CVD apparatus 30 comprises a plurality of substrate setting jigs 31 for holding the substrate 1, and a reaction vessel 32 made of heat-resistant alloy steel that covers the substrate setting jigs 31. A temperature control device 33 for controlling the temperature inside the reaction vessel 32 is provided around the reaction vessel 32. The reaction vessel 32 is provided with a gas inlet pipe 35 having a gas inlet port 34. The gas inlet pipe 35 extends vertically in the internal space of the reaction vessel 32 where the substrate setting jigs 31 are placed, and is rotatable about the vertical axis, and is provided with a plurality of ejection holes (through holes 36) for ejecting gas into the reaction vessel 32. Using this CVD apparatus 30, the coating is constructed as follows: α-Al ２ O ３ layer, TiCNO layer, TiC ｘ N ｙ Layers and TiN layers can be formed.

[0092] If the coating includes the "other layer" described in Embodiment 1, the "other layer" can be formed by a conventionally known method.

[0093] <Step 2a: α-Al by CVD method> ２ O ３ Layer formation process > In step 2a, α-Al is formed by CVD. ２ O ３ A layer is formed. More specifically, first the substrate 1 is placed in the substrate setting jig 31, and while controlling the temperature and pressure inside the reaction vessel 32 within a predetermined range, α-Al ２ O ３ The raw material gas for the layer is introduced into the reaction vessel 32 from the gas introduction pipe 35. This allows α-Al to be added to the substrate 1. ２ O ３ A layer is formed on the substrate 1, and α-Al ２ O ３ A "first cutting tool precursor" with layers formed is obtained.

[0094] α-Al ２ O ３ As a raw material gas for the layer, AlCl ３ CO ２HCl, CO, H ２ S, and H ２ A mixed gas is used.

[0095] AlCl in mixed gas ３ The content may be 2.0 atm% or more and 4.0 atm% or less. CO in mixed gas ２ The content of may be 1.0 atm% or more and 3.0 atm% or less. The HCl content in the mixed gas may be 2.0 atm% or more and 6.0 atm% or less. The CO content in the mixed gas may be 2.0 atm% or more and 3.0 atm% or less. H in the mixed gas ２ The content of S may be 0.1 atm% or more and 1.0 atm% or less.

[0096] The temperature inside the reaction vessel 32 may be controlled to be between 900°C and 1100°C, and the pressure inside the reaction vessel 32 may be controlled to be between 60 hPa and 80 hPa. The gas introduction pipe 35 may also be rotated when introducing the gas.

[0097] Regarding the above manufacturing method, by controlling each condition of the CVD method, α-Al ２ O ３ The layer configuration changes. For example, by adjusting the film deposition time, α-Al ２ O ３ The thickness of the layer is controlled.

[0098] <Step 2c: Step to form TiCNO layer by CVD> In step 2c, a TiCNO layer is formed by CVD. More specifically, first, α-Al is placed on the substrate 1. ２ O ３ The "first cutting tool precursor" with the layer formed is placed in the base material set jig 31, and while controlling the temperature and pressure inside the reaction vessel 32 within a predetermined range, the raw material gas for the TiCNO layer is introduced into the reaction vessel 32 from the gas introduction pipe 35. This results in α-Al ２ O ３ A TiCNO layer is formed on the layer, and α-Al ２ O ３ A "first' cutting tool precursor" is obtained in which a TiCNO layer is formed on the layer.

[0099] As a source gas for the TiCNO layer, TiCl ４ ,CH ３ CN, CO, N ２ , and H ２ A mixed gas is used.

[0100] TiCl in mixed gases ４ The content may be 0.5 atm% or more and 3.0 atm% or less. CH in mixed gas ３ The CN content may be between 0.01 atm% and 3.0 atm%. The CO content in the mixed gas may be between 1.0 atm% and 4.0 atm%. ２ The content may be 10 atm% or more and 40 atm% or less.

[0101] The temperature inside the reaction vessel 32 may be controlled to be between 900°C and 1100°C, and the pressure inside the reaction vessel 32 may be controlled to be between 180 hPa and 220 hPa. The gas introduction pipe 35 may also be rotated when introducing the gas.

[0102] Regarding the above manufacturing method, the characteristics of the TiCNO layer can be changed by controlling each condition of the CVD process. For example, the thickness of the TiCNO layer can be controlled by adjusting the deposition time.

[0103] <Step 2b: TiC by CVD method> ｘ N ｙ Layer formation process > In step 2b, TiC is formed by CVD. ｘ N ｙ A layer is formed. More specifically, if the second step c is not performed, first, α-Al is placed on the substrate 1. ２ O ３ The "first cutting tool precursor" with the layer formed is placed on the base material set jig 31, and while controlling the temperature and pressure inside the reaction vessel 32 within a predetermined range, TiC ｘ N ｙ The raw material gas for the layer is introduced into the reaction vessel 32 from the gas introduction pipe 35. This allows α-Al to be produced. ２ O ３ TiC on a layer ｘ N ｙ A layer is formed.

[0104] Furthermore, if step 2c is performed, first, α-Al ２ O ３ A "first cutting tool precursor" with a TiCNO layer formed on top of it is placed in the base material set jig 31, and while controlling the temperature and pressure in the reaction vessel 32 to a predetermined range, TiC ｘ N ｙ The raw material gas for the layer is introduced into the reaction vessel 32 from the gas introduction pipe 35. This creates a TiC NO layer on top of the TiC NO layer. ｘ N ｙ A layer is formed.

[0105] TiC ｘ N ｙ As a raw material gas for the layer, TiCl ４ ,CH ３ CN, CO, N ２ , and H ２ A mixed gas is used.

[0106] The CO content c1 in the mixed gas is between 0.15 atm% and 0.4 atm%. Therefore, TiC ｘ N ｙ The crystal diameter can be reduced while maintaining the columnar structure of the crystal. TiCl in mixed gases ４ The content c3 may be 0.5 atm% or more and 3.0 atm% or less. CH in mixed gas ３ The CN content c4 may be 0.01 atm% or more and 3.0 atm% or less. ２ The content c2 may be 10 atm% or more and 40 atm% or less.

[0107] The temperature inside the reaction vessel 32 may be controlled to be between 900°C and 1100°C, and the pressure inside the reaction vessel 32 may be controlled to be between 80 hPa and 100 hPa. The gas introduction pipe 35 may also be rotated when introducing the gas.

[0108] Regarding the above manufacturing method, by controlling each condition of the CVD method, TiC ｘ N ｙ The layer configuration changes. For example, by adjusting the deposition time, TiC ｘ N ｙ The thickness of the layer is controlled.

[0109] <Step 2d: Process for forming a TiN layer by CVD> In step 2d, a TiN layer is formed by CVD. More specifically, in step 2b, TiC ｘ N ｙ A cutting tool precursor with a layer formed on it (second cutting tool precursor) is placed in the base material set jig 31, and while controlling the temperature and pressure inside the reaction vessel 32 within a predetermined range, the raw material gas for the TiN layer is introduced into the reaction vessel 32 from the gas introduction pipe 35. This results in TiC ｘ N ｙ A TiN layer is formed on top of the layer.

[0110] For the TiN layer, the source gas is TiCl ４ , N ２ , and H ２ A mixed gas is used.

[0111] TiCl in mixed gases ４ The content may be 0.5 atm% or more and 3.0 atm% or less. N in mixed gas ２ The content may be 10 atm% or more and 40 atm% or less.

[0112] The temperature inside the reaction vessel 32 may be controlled to be between 900°C and 1100°C, and the pressure inside the reaction vessel 32 may be controlled to be between 60 hPa and 80 hPa. The gas introduction pipe 35 may also be rotated when introducing the gas.

[0113] Regarding the above manufacturing method, the characteristics of the TiN layer can be changed by controlling each condition of the CVD process. For example, the thickness of the TiN layer can be controlled by adjusting the deposition time.

[0114] <Other Processes> In addition to the above processes, the second process may include surface treatment processes such as surface grinding and blasting.

[0115] ≪Features of the manufacturing method of the cutting tool of this embodiment≫ In the manufacturing method of the cutting tool of this embodiment, in step 2b, the CO content in the mixed gas is 0.15 atm% or more and 0.4 atm% or less. As a result, the coating is α-Al disposed on the substrate 1. ２ O ３ The layer and the α-Al２ O ３ TiC arranged in layers ｘ N ｙ A layer and including multiple TiC ｘ N ｙ The TiC is composed of crystals. ｘ N ｙ In the layer, the TiC ｘ N ｙ The crystals are columnar crystals extending along the direction from the substrate 1 to the surface of the coating, and the TiC ｘ N ｙ The crystal diameter of the crystal can be adjusted to a desired range, and x and y can also be adjusted to a desired range. The reason for this is presumed to be as follows.

[0116] Multiple TiCs ｘ N ｙ The TiC is composed of crystals. ｘ N ｙ In the layer, the TiC ｘ N ｙ The crystals are columnar crystals that extend along the direction from the substrate to the surface of the coating, and the TiC ｘ N ｙ Keeping the crystal diameter of the crystal small is, for example, the TiC ｘ N ｙ It has been conventionally known that this can be achieved by performing the deposition of the layer at a low temperature (for example, around 800°C). However, α-Al ２ O ３ TiC on a layer ｘ N ｙ When arranging layers, α-Al ２ O ３ Because the layer is executed at high temperatures (for example, around 1000°C), TiC ｘ N ｙ The layer deposition could not be performed at low temperatures (for example, around 800°C). Also, α-Al ２ O ３ α-Al in the layer ２ O ３ Due to the tendency for the particles to become coarse, α-Al ２ O ３ TiC arranged in layers ｘ N ｙ TiC in layers ｘ N ｙThe crystals could not be made into fine grains. Therefore, TiC ｘ N ｙ The crystals are columnar crystals that extend along the direction from the substrate to the surface of the coating, and the TiC ｘ N ｙ We were unable to keep the crystal diameter small enough.

[0117] In the cutting tool manufacturing method of this embodiment, in step 2b, the CO content in the mixed gas is 0.15 atm% or more and 0.4 atm% or less. If the CO content is high (i.e., greater than 0.4 atm%), it becomes difficult to control the growth direction and thus the columnar structure cannot be maintained. On the other hand, if the CO content is moderately low (i.e., 0.15 atm% or more and 0.4 atm%), it becomes easier to control the growth direction and thus the columnar structure can be maintained. For this reason, the coating is α-Al arranged on the substrate 1. ２ O ３ The layer and the α-Al ２ O ３ TiC arranged in layers ｘ N ｙ A layer and including multiple TiC ｘ N ｙ TiC composed of crystals ｘ N ｙ In the layer, the TiC ｘ N ｙ The crystals are columnar crystals extending along the direction from the substrate 1 to the surface of the coating, and the TiC ｘ N ｙ The crystal diameter can be adjusted to a desired range. Conventionally, in order to stabilize the control of the CO gas flow rate, the flow rate was increased, and the CO content in the mixed gas was outside the range of 0.15 atm% to 0.4 atm%. Furthermore, in step 2b, assuming that the CO content in the mixed gas is 0.15 atm% to 0.4 atm%, the N content in the mixed gas relative to the CO content c1 in the mixed gas is... ２ The ratio of the content c2 to c1 is 10 or more and 400 or less, and the CH content in the mixed gas is ３ N in the mixed gas relative to the CN content c4 ２The ratio of TiCl content c2 to c4 is 75 or more, and the TiCl content in the mixed gas is 75 or more. ４ The CO content c1 in the mixed gas relative to the content c3 of N ２ The content of c2 and CH ３ CN content c4, H ２ The ratio of the sum of the content c5 and (c1 + c2 + c4 + c5) / c3 is between 49 and 99. This allows for appropriate changes in the supply amounts of C atoms and N atoms, thereby enabling adjustment of the values ​​of x and y to a desired range. The present inventors have discovered, through diligent research, that the cutting tool of this disclosure can be realized by employing such a manufacturing method.

[0118] This embodiment will be described in more detail by reference to examples. However, this embodiment is not limited by these examples.

[0119] <<Preparation of Cutting Tools>> Cutting tools for samples 1-22 and 101-109 were prepared as follows.

[0120] <<Step 1>> As a base material, a cemented carbide cutting tip (shape: CNMG120408N-UX, manufactured by Sumitomo Electric Hardmetal Co., Ltd., JIS B4120 (2013)) having the following composition was prepared. (Composition of base material) ・WC content: remainder ・TaC content: 2.0 mass% ・NbC content: 1.0 mass% ・Co content: 10.0 mass%

[0121] <<Second Step>> Under the conditions described in Tables 1-1 and 1-2, α-Al is applied to the above substrate by CVD. ２ O ３ A layer was formed (step 2a). The film formation time was α-Al ２ O ３ The layers were adjusted as appropriate so that they had the thicknesses shown in Tables 4-1 and 4-2. In sample 108, the conditions for step 2a were the same as those shown in the example of Patent Document 1, except for the film formation time (i.e., the condition that contributes to the thickness). ２ O ３This corresponds to the film deposition conditions for the layer. Next, with respect to samples 17-19 and sample 109, the above α-Al was deposited by CVD under the conditions described in Tables 2-1 and 2-2. ２ O ３ A TiCNO layer was formed on the layer (step 2c). The deposition time was adjusted as appropriate so that the TiCNO layer had the thickness described in Tables 4-1 and 4-2. For sample 109, the conditions in step 2c, except for the deposition time (i.e., the conditions contributing to the thickness), correspond to the deposition conditions for the "upper layer" of "Invention 1" shown in the example of Patent Document 2. Next, for samples 1 to 16, samples 20 to 22, and samples 101 to 108, the above α-Al was deposited by CVD under the conditions described in Tables 3-1 and 3-2. ２ O ３ TiC on a layer ｘ N ｙ A layer was formed (step 2b). The film deposition time was TiC ｘ N ｙ The layers were appropriately adjusted to the thicknesses shown in Tables 5-1 and 5-2. In sample 108, the conditions in step 2a correspond to the film formation conditions for the TiCN layer shown in the example of Patent Document 1, except for the film formation time (i.e., the condition contributing to the thickness). Furthermore, for samples 17 to 19, TiC was deposited on the TiCN NO layer by CVD under the conditions described in Table 3-1. ｘ N ｙ A layer was formed (step 2b). The film deposition time was TiC ｘ N ｙ The layers were adjusted as appropriate so that they had the thicknesses shown in Table 5-1. Next, with respect to sample 20, the above TiC was processed by CVD under the following conditions. ｘ N ｙ A TiN layer was formed on the layer (step 2d). The film deposition time was adjusted as appropriate so that the TiN layer reached the thickness shown in Table 6-1. (Conditions for step 2d) - Composition of mixed gas: TiCl ４ (3.0 atm%), N ２ (24 atm%), H ２(Remaining) ・Temperature: 1000℃ ・Pressure: 70hPa Note that if "-" is written in all columns of Table 2-1 and Table 2-2, it means that step 2c was not performed. Also, if "-" is written in all columns of Table 3-2, it means that step 2b was not performed.

[0122] Based on the above, cutting tools were fabricated for samples 1-22 and 101-109. Regarding the TiCNO layer in sample 109, the TiCNO layer is composed of multiple TiC ｘ N ｙ It consists of O particles, and the TiC ｘ N ｙ The x-coordinate of the O particle was 0.4, the y-coordinate was 0.55, the aspect ratio was 40, the crystal diameter was 0.03, and the hardness of the TiCNO layer was 22 GPa. Here, the measurement method was used when the measurement targets were the TiCNO layer and TiC ｘ N ｙ Except for the fact that it was an O particle, the x, y, aspect ratio, crystal diameter, and hardness were measured in the same manner as described in Embodiment 1.

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[0135] ≪Evaluation of Cutting Tool Characteristics≫ <α-Al２ O ３ Layer composition > Regarding the cutting tool for each sample, α-Al ２ O ３ The layer composition was determined by the method described in Embodiment 1. The obtained results are shown in Tables 4-1 and 4-2 as "α-Al ２ O ３ Note this in the "Composition" column of the "Layer" column. Also, see "α-Al" in Tables 4-1 and 4-2. ２ O ３ If the component name is listed in the "Composition" column of the "Layer" column, then α-Al ２ O ３ The term "layer" means that it consists of the component represented by that component name.

[0136] <α-Al ２ O ３ Layer thickness > For cutting tools related to each sample, α-Al ２ O ３ The thickness of the layer was determined by the method described in Embodiment 1. The obtained results are shown in Tables 4-1 and 4-2 as "α-Al ２ O ３ Enter the thickness [μm] in the "Layer" column.

[0137] <α-Al ２ O ３ Particle size > For the cutting tool used for each sample, α-Al ２ O ３ The particle size was determined by the method described in Embodiment 1. The obtained results are shown in Tables 4-1 and 4-2 as "α-Al ２ O ３ Enter the value in the "Particle Size [μm]" field under the "Layer" section.

[0138] <Composition of the TiCNO Layer> For each cutting tool related to the sample, the composition of the TiCNO layer was determined by the method described in Embodiment 1. The obtained results are recorded in the "Composition" column of the "TiCNO Layer" column in Tables 4-1 and 4-2. In cases where a component name is listed in the "Composition" column of the "TiCNO Layer" column in Tables 4-1 and 4-2, it means that the TiCNO layer consists of the component represented by that component name.

[0139] <Thickness of the TiCNO layer> For each cutting tool related to the sample, the thickness of the TiCNO layer was determined by the method described in Embodiment 1. The results obtained are recorded in the "Thickness [μm]" column of the "TiCNO layer" column in Tables 4-1 and 4-2.

[0140] <TiC ｘ N ｙ Layer composition > Cutting tools for each sample, TiC ｘ N ｙ The layer composition was determined by the method described in Embodiment 1. The obtained results are shown in Tables 5-1 and 5-2 as "TiC ｘ N ｙ Note that the "Composition", "x", and "y" columns in the "Layer" column should be filled in accordingly. ｘ N ｙ If the component name is listed in the "Composition" column of the "Layer" column, then TiC ｘ N ｙ The term "layer" means that it consists of the component represented by that component name.

[0141] <TiC ｘ N ｙ Layer thickness > Cutting tools for each sample, TiC ｘ N ｙ The thickness of the layer was determined by the method described in Embodiment 1. The obtained results are shown in Tables 5-1 and 5-2 as "TiC ｘ N ｙ Enter the thickness [μm] in the "Layer" column.

[0142] <TiC ｘ N ｙ Crystal diameter > Cutting tools for each sample, TiC ｘ N ｙ The crystal diameter of the crystal was determined by the method described in Embodiment 1. The obtained results are shown in Tables 5-1 and 5-2 as "TiC ｘ N ｙ "TiC" in the "Layer" column ｘ N ｙ Enter the value in the "Crystal Diameter [μm]" field under the "Crystal" section.

[0143] <TiC ｘ N ｙ Crystal aspect ratio > Cutting tools for each sample, TiC ｘ Nｙ The aspect ratio of the crystal was determined by the method described in Embodiment 1. The obtained results are shown in Tables 5-1 and 5-2 as "TiC ｘ N ｙ "TiC" in the "Layer" column ｘ N ｙ Enter the value in the "Aspect Ratio" field under the "Crystal" section.

[0144] <TiC ｘ N ｙ Layer hardness > For cutting tools used with each sample, TiC ｘ N ｙ The hardness of the layer was determined by the method described in Embodiment 1. The obtained results are shown in Tables 5-1 and 5-2 as "TiC ｘ N ｙ Note this in the "Hardness [GPa]" field under the "Layer" section.

[0145] <Composition of the TiN Layer> For each cutting tool related to the sample, the composition of the TiN layer was determined by the method described in Embodiment 1. The obtained results are recorded in the "Composition" column of the "TiN Layer" column in Tables 6-1 and 6-2. In cases where a component name is listed in the "Composition" column of the "TiN Layer" column in Tables 6-1 and 6-2, it means that the TiN layer consists of the component represented by that component name.

[0146] <Thickness of the TiN layer> For each cutting tool related to the sample, the thickness of the TiN layer was determined by the method described in Embodiment 1. The results obtained are recorded in the "Thickness [μm]" column of the "TiN layer" column in Tables 6-1 and 6-2.

[0147] <Coating Thickness> For each cutting tool related to the sample, the coating thickness was determined by the method described in Embodiment 1. The results obtained are recorded in the "Thickness [μm]" column of the "Coating" column in Tables 6-1 and 6-2.

[0148] ≪Cutting Test≫ Using the cutting tool for each sample, cutting was performed under the following cutting conditions, and the amount of coating wear [mm] on the flank was measured every minute of cutting time. The time when the amount of wear exceeded 0.2 mm was recorded as the tool life [minutes]. The results obtained are recorded in the "Tool Life [minutes]" column of the "Cutting Test" column in Tables 6-1 and 6-2. (Cutting conditions) ・Workpiece material: FCD450 ・Cutting speed: 200 m / min ・Feed rate: 0.3 mm / rev ・Depth of cut: 2.0 mm ・Water-soluble cutting fluid: Yes (wet) The above cutting conditions correspond to the cutting conditions for cast iron machining.

[0149] In the above cutting test, a tool life of 15 minutes or more indicates that the cutting tool has excellent tool life, especially under the cutting conditions for machining cast iron.

[0150] The cutting tools for samples 1 to 22 correspond to the examples. The cutting tools for samples 101 to 109 correspond to the comparative examples. From the results of the cutting tests shown in Tables 6-1 and 6-2, it was found that the cutting tools for samples 1 to 22 have superior tool life compared to the cutting tools for samples 101 to 109, especially in the machining of cast iron.

[0151] Based on the above, it was found that the cutting tools related to samples 1 to 22 have excellent tool life, especially in the machining of cast iron.

[0152] As described above, embodiments and examples of this disclosure have been explained, but it is also intended from the outset that the configurations of each of the above embodiments and examples may be combined as appropriate or modified in various ways.

[0153] 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 equivalents and within the scope.

[0154] 1 base material, 2 coating, 3 α-Al ２ O ３ layer, 4 TiC ｘ N ｙLayers: 5 TiCNO layer, 6 TiN layer, 10 cutting tool, 30 CVD apparatus, 31 substrate setting jig, 32 reaction vessel, 33 temperature control device, 34 gas inlet, 35 gas inlet pipe, 36 through hole.

Claims

1. A cutting tool comprising a substrate and a coating disposed on the substrate, wherein the coating is α-Al ２ O ３ layer, and TiC ２ N ３ layer disposed on the α-Al ｘ N ｙ layer, wherein x and y satisfy the relationships of Formula 1 and Formula 2, 0.7 ≦ x + y ≦ 1.3 Formula 1 y ≧ 1.5x Formula 2 The TiC ｘ N ｙ layer is composed of a plurality of TiC ｘ N ｙ crystals, and the TiC ｘ N ｙ crystals are columnar crystals extending along the direction from the substrate to the surface of the coating, and the crystal diameter of the TiC ｘ N ｙ crystals is 0.05 μm or more and 0.5 μm or less. A cutting tool.

2. The TiC ｘ N ｙ The cutting tool according to claim 1, wherein the aspect ratio of the crystal is 10 or more and 30 or less.

3. The TiC ｘ N ｙ The cutting tool according to claim 1 or claim 2, wherein the thickness of the layer is 0.5 μm or more and 5 μm or less.

4. The α-Al ２ O ３ The layer consists of multiple α-Al ２ O ３ Consists of particles, the aforementioned α-Al ２ O ３ A cutting tool according to any one of claims 1 to 3, wherein the particle size is 0.3 μm or more and 1.0 μm or less.

5. The coating is the α-Al ２ O ３ Layer and the TiC ｘ N ｙ Between the layers, the α-Al ２ O ３ Layer and the TiC ｘ N ｙ A cutting tool according to any one of claims 1 to 4, further comprising a TiCNO layer disposed in contact with a layer, wherein the thickness of the TiCNO layer is 1 μm or less.

6. The coating is the TiC ｘ N ｙ A cutting tool according to any one of claims 1 to 5, further comprising a TiN layer disposed in contact with the layer.

7. The cutting tool according to any one of claims 1 to 6, wherein x and y further satisfy the relationship in Equation 3. y > 1.5x Equation 3

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