Cutting tools

Abstract

The cutting tool is a cutting tool comprising a substrate and a coating disposed on the substrate, wherein the coating comprises an α-Al2O3 layer disposed on the substrate and TiC x N y layer, and x and y satisfy the relationships of Formula 1 and Formula 2, and the TiC x N y layer consists 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. Cutting tool.

Description

Technical Field

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

Background Art

[0002] Conventionally, a cutting tool including a substrate and a coating disposed on the substrate has been used for cutting. The coating includes an α-Al2O3 layer disposed on the substrate and a TiCN layer or a TiCNO layer disposed on the α-Al2O3 layer (Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

[0004] The cutting tool of the present disclosure is a cutting tool including a substrate and a coating disposed on the substrate. The coating includes an α-Al2O3 layer disposed on the substrate and a TiC 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[[ID=..]] 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. The crystal diameter of the TiC x N y crystals is 0.05 μm or more and 0.5 μm or less.

Brief Description of the Drawings

[0005] [Figure 1] Figure 1 is a schematic diagram showing an example of a cross-section of a cutting tool according to Embodiment 1. [Figure 2] Figure 2 is a schematic diagram showing another example of a cross-section of a cutting tool according to Embodiment 1. [Figure 3] Figure 3 is a schematic cross-sectional view of an example of a CVD (Chemical Vapor Deposition) apparatus used in the manufacture of the cutting tools of this disclosure. [Modes for carrying out the invention]

[0006] [Issues this disclosure aims to address] In recent years, the load on the cutting edge of cutting tools has tended to increase due to factors such as the increasing difficulty of machining workpieces, the increase in cutting speed to improve machining efficiency, and the resulting increase in feed rate and depth of cut. As a result, the demand for improved cutting tool characteristics is increasing. This is also true for cutting tools used in medium-speed machining of steel. When a cutting tool comprising 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 TiCN layer or TiCNO layer disposed on the α-Al2O3 layer (Patent Documents 1-2) is used in medium-speed machining of steel, the tool life was sometimes insufficient. As a result, it was difficult for such cutting tools to exhibit excellent tool life, especially in medium-speed machining of steel. Therefore, especially in medium-speed machining of steel, there is a need to provide cutting tools with excellent "wear resistance" to give them excellent tool life.

[0007] Therefore, the present disclosure aims to provide a cutting tool that has excellent tool life, particularly in medium-speed machining of steel.

[0008] [Effects of this disclosure] According to this disclosure, it is possible to provide cutting tools that have excellent tool life, especially in medium-speed machining of steel.

[0009] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and described. (1) The cutting tool of the present disclosure comprises a base material and a coating disposed on the base material, wherein the coating comprises an α-Al2O3 layer disposed on the base material and a TiC disposed on the α-Al2O3 layer. x N y A layer and a, 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 aforementioned TiC x N y The layer consists of multiple TiC x N y Composed of crystals, 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 The crystal diameter is between 0.05 μm and 0.5 μm.

[0010] According to this disclosure, it is possible to provide cutting tools that have excellent tool life, especially in medium-speed machining of steel.

[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 better tool life, especially in medium-speed machining of steel.

[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 better tool life, especially in medium-speed machining of steel.

[0013] (4) In any of (1) to (3) above, the α-Al2O3 layer may consist of a plurality of α-Al2O3 particles, and the particle size of the α-Al2O3 particles may be 0.3 μm or more and 1.0 μm or less. This makes it possible to provide a cutting tool with better tool life, especially in medium-speed machining of steel.

[0014] (5) In any of (1) to (4) above, the coating comprises the α-Al2O3 layer and the TiC x N y Between the layers, the α-Al2O3 layer and the TiC x N y The 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 better tool life, especially in medium-speed machining of steel.

[0015] (6) In any of (1) to (5) 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 superior tool life, especially in medium-speed machining of steel.

[0016] [Details of the embodiments of this disclosure] A specific example of a cutting tool according to one embodiment of this disclosure (hereinafter also referred to as "this embodiment") will be described below with reference to the drawings. In the drawings of this disclosure, the same reference numerals represent the same part or a corresponding part. Furthermore, dimensional relationships such as length, width, thickness, and depth have been appropriately modified for clarity and simplification of the drawings and do not necessarily represent actual dimensional relationships.

[0017] In this disclosure, the notation "A~B" means an upper and lower limit of the range (i.e., A or greater and B or less), and if there is no unit specified for A, but a unit is specified only for B, then the unit for A and the unit for B are the same.

[0018] 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.

[0019] [Embodiment 1: Cutting Tool] A cutting tool according to one embodiment of the present disclosure will be described with reference to Figures 1 and 2. Figure 1 is a schematic cross-sectional view illustrating one embodiment of the cutting tool of the present disclosure. Figure 2 is a schematic cross-sectional view illustrating another embodiment of the cutting tool of the present disclosure. 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 comprises an α-Al2O3 layer 3 disposed on the base material 1 and TiC disposed on the α-Al2O3 layer 3. x N y Layer 4 and, including, 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, 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.

[0020] According to this disclosure, it is possible to provide a cutting tool 10 that has excellent tool life, especially in medium-speed machining of steel. The reason for this is presumed to be as follows.

[0021] In the cutting tool 10 of this embodiment, the coating 2 consists of an α-Al2O3 layer 3 disposed on the substrate 1 and TiC disposed on the α-Al2O3 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 yLayer 4 consists of multiple TiC x N y It consists of crystals, 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. x N y In layer 4, the amount of carbon atoms contributing to hardness is sufficiently greater than the amount of nitrogen atoms, and the TiC x N y As the crystal diameter becomes finer, the hardness of the coating can be improved. Therefore, when the cutting tool 10 of this embodiment is used in machining where the temperature does not rise easily (for example, medium-speed machining of steel), abrasion wear on the flank surface of the cutting tool is less likely to occur, resulting in excellent tool life.

[0022] ≪Cutting tools≫ As shown in Figures 1 and 2, 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 the area of ​​the base material 1 that is surrounded by the cutting edge and a hypothetical plane 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, depending on the size and shape of the base material 1.

[0023] 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.

[0024] ≪Base material≫ The cutting tool 10 comprises a base material 1. Any of the conventionally known base materials 1 of this type can be used as the base material 1. For example, it is preferable that the base material is a cemented carbide (WC-based cemented carbide, cemented carbide containing WC and Co, cemented carbide with carbonitrides such as Ti, Ta, and Nb added), a cermet (mainly composed of TiC, TiN, TiCN, etc.), high-speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, etc.), a cubic boron nitride sintered body, or a diamond sintered body.

[0025] Among these various base materials 1, it is particularly preferable to select WC-based cemented carbide or cermet (especially TiCN-based cermet). These base materials 1 have an excellent balance of hardness and strength, especially at high temperatures, and when used as the base material 1 for a cutting tool 10, they can contribute to extending the lifespan of the cutting tool 10.

[0026] ≪Coating≫ The cutting tool 10 includes a coating 2 disposed on a substrate 1. The coating 2 consists of an α-Al2O3 layer 3 disposed on the substrate 1 and TiC disposed on the α-Al2O3 layer 3. x N y The coating 2 includes layer 4 and TiC. x N y Between layer 4, the α-Al2O3 layer 3 and the TiC x N y A TiCNO layer 5 may be further included, positioned in contact with layer 4. This allows the TiCNO layer 5 to be connected to the α-Al2O3 layer 3 and TiC x N yBecause it has excellent adhesion to layer 4, it is possible to provide a cutting tool 10 with superior tool life, especially in medium-speed machining of steel. The coating 2 consists of α-Al2O3 layer 3 and TiC x N y It may consist of four layers, such as α-Al2O3 layer 3 and TiC x N y It may consist only of layer 4 and TiCNO layer 5, and to the extent that the effects of this disclosure are not impaired, α-Al2O3 layer 3, TiC x N y The structure may also include layers other than layer 4 and TiCNO layer 5 (referred to as "other layers" below).

[0027] 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.

[0028] The thickness of coating 2 can be measured by observing a cross-section of coating 2 along the normal direction of its surface 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.

[0029] ≪α-Al2O3 layer≫ <Composition of the α-Al2O3 layer> The α-Al2O3 layer 3 may consist of a plurality of α-Al2O3 particles. In this disclosure, "consisting of α-Al2O3 particles" means that it may consist only of α-Al2O3 particles, and that unavoidable impurities may be included in addition to the α-Al2O3 particles, 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 the α-Al2O3 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.

[0030] The content of α-Al2O3 particles in α-Al2O3 layer 3 is determined by X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDX). The content of unavoidable impurities in α-Al2O3 layer 3 is measured by secondary ion mass spectrometry (SIMS). It has been confirmed that, as long as measurements are taken in the same α-Al2O3 layer 3, there is almost no variation in the measurement results even if the measurement site is arbitrarily selected.

[0031] <α-Al2O3 particles> The particle size of the α-Al2O3 particles may be between 0.3 μm and 1.0 μm. This reduces the scale of α-Al2O3 particle shedding, thus providing a cutting tool 10 with superior tool life, especially in medium-speed machining of steel. The particle size may also be between 0.4 μm and 0.9 μm, between 0.45 μm and 0.85 μm, or between 0.5 μm and 0.8 μm.

[0032] The particle size of α-Al2O3 particles can be measured using the following procedure (A1) to (A6).

[0033] (A1) The cutting tool 10 is cut along the normal of the rake face of the substrate 1 using a diamond wire to expose the cross-section of the α-Al2O3 layer 3. Ion milling is performed on the exposed cross-section using Ar ions to make the cross-section mirror-finish. The conditions for the ion milling are as follows. • Acceleration voltage: 6kV • Irradiation angle: 0° from the straight line parallel to the thickness direction of the α-Al2O3 layer 3 in the cross-section of the α-Al2O3 layer 3. • Irradiation time: 6 hours

[0034] (A2) The cross-section in a mirror state is electrically world Emission type scanning electron microscope ( FE -Observation is performed at 5,000x magnification using SEM to obtain backscattered electron images (EBSD).

[0035] (A3) In the above EBSD, the measurement range is set such that it includes the interface of the α-Al2O3 layer 3 close to the substrate 1 and the interface of the α-Al2O3 layer 3 close to 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).

[0036] (A4) For any one α-Al2O3 particle within the measurement range, measure the lateral diameter at any three locations. By calculating the average (arithmetic mean) of the lateral diameters at any three locations, determine the average lateral diameter of any one α-Al2O3 particle.

[0037] (A5) For each of the other 29 α-Al2O3 particles within the measurement range, determine the average transverse diameter using the same method as in (A4) above.

[0038] (A6) The particle size of the α-Al2O3 particles is determined by calculating the average (arithmetic mean) of the average lateral diameter for any 30 α-Al2O3 particles within the measurement range.

[0039] Furthermore, it has been confirmed that, as long as measurements are taken on the same α-Al2O3 layer 3, there is almost no variation in the measurement results even if the measurement location is arbitrarily selected.

[0040] <Thickness of the α-Al2O3 layer> The thickness of the α-Al2O3 layer 3 may be 4 μm or more and 15 μm or less. By this, since the α-Al2O3 layer 3 has a sufficient thickness, the wear resistance can be improved, and by appropriately suppressing the thickness of the α-Al2O3 layer 3, sufficient chipping resistance can be exhibited. The thickness of the α-Al2O3 layer 3 may be 5 μm or more and 10 μm or less, and may be 6 μm or more and 9 μm or less.

[0041] ≪TiC x N y layer≫ <TiC x N y Composition of layer> TiC x N y The TiC x N y layer 4 is composed of a plurality of TiC x N y crystals. In the present disclosure, "composed of TiC x N y crystals" means that it may be composed only of TiC x N y crystals, and in a range that does not impair the effects of the present disclosure, it means that inevitable impurities can be included in addition to the TiC x N y crystals. Examples of the inevitable impurities include chlorine (Cl) and the like. The total content rate of the inevitable impurities in the TiC

[0042] N x layer 4 may be, for example, 0 mass% or more and 0.10 mass% or less, or may be 0.01 mass% or more and 0.05 mass% or less.

[0042] TiC x N y The content rate of the TiC x N y crystals in the layer 4 is specified by X-ray diffraction method (XRD) and energy dispersive X-ray analysis (EDX). The content rate of the inevitable impurities in the TiC x N y layer 4 is measured by secondary ion mass spectrometry (SIMS). As long as it is measured in the same TiC x N y layer 4, it has been confirmed that even if the measurement location is arbitrarily selected, there is almost no variation in the measurement results.

[0043] 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 ensures that the ratio of Ti atoms to C atoms and N atoms is within an appropriate range, and that the proportion of C atoms in TiCN is sufficiently high, thereby improving the hardness 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, 1.5xy, may be greater than 0 (i.e., x and y may further satisfy the relationship in equation 3). y < 1.5x Equation 3 This allows for further improvement of the hardness of coating 2. The lower limit of the difference between 1.5x and y, 1.5xy, may be 0.1 or greater, 0.2 or greater, or 0.3 or greater. The upper limit of the difference between 1.5x and y, 1.5xy, may be 1 or less, or 0.5 or less.

[0044] The above x may be between 0.35 and 0.65. This will result in a sufficiently high ratio of C atoms, thereby further improving the hardness of coating 2. x may also be between 0.4 and 0.65, or between 0.45 and 0.6.

[0045] The above value of y may be between 0.35 and 0.6. This makes it easier to achieve an appropriate sum of the ratios of C atoms and N atoms relative to the ratio of Ti atoms in TiCN, thereby further improving the hardness of coating 2. The value of y may also be between 0.4 and 0.55, or between 0.45 and 0.5.

[0046] The above x and y are measured by following the steps (B1) to (B2) below.

[0047] (B1) Cut the cutting tool 10 with a diamond wire along the normal to the surface of the cutting tool 10, TiC x Ny Expose the cross-section of layer 4. Perform focused ion beam processing (hereinafter also referred to as "FIB processing") on the exposed cross-section to make the cross-section mirror-like.

[0048] (B2)TiC x N y In the cross-section of layer 4, perform rectangular analysis using an energy dispersive X-ray spectroscope (EDX) attached to a transmission electron microscope (TEM: Transmission Electron Microscope) (TEM-EDX) to identify TiC x N y Identify the composition of layer 4. The rectangular analysis is performed on three non-overlapping 0.5 μm × 2 μm rectangular measurement regions set within the cross-section of layer 4. For each of the three measurement regions, measure x' and y'. Calculate the average of x' and the average of y' (arithmetic mean) for the three measurement regions. The average corresponds to x and y in layer 4. x N y It is carried out for three non-overlapping 0.5 μm × 2 μm rectangular measurement regions set within the cross-section of layer 4. In each of the three measurement regions, measure x' and y'. Calculate the average of x' and the average of y' (arithmetic mean) for the three measurement regions. The average corresponds to TiC x N y It corresponds to x and y in layer 4.

[0049] It has been confirmed that as long as measurements are made on the same sample, even if the selection location of the measurement field is arbitrarily changed and multiple measurements are performed, there is almost no variation in the measurement results.

[0050] <TiC x N y Crystal> TiC x N y The TiC x N y crystal is a columnar crystal extending along the direction from the substrate 1 to the surface of the coating 2. As a result, it becomes easier to suppress the progress of cracks along the direction perpendicular to the normal direction of the surface of the coating 2, and thus the hardness of the coating 2 can be improved. Here, "the TiC x N y crystal is a columnar crystal extending along the direction from the substrate 1 to the surface of the coating 2" means that the aspect ratio of the TiC

[0051] TiC x N y The aspect ratio of the crystal may be between 10 and 30. x N y Because crystal shedding is easily suppressed, a cutting tool 10 with superior tool life can be provided, especially in medium-speed machining of steel. x N y The aspect ratio of the crystal may be between 10 and 25, or between 10 and 20.

[0052] TiC x N y The aspect ratio of a crystal can be measured using the following procedure (C1) to (C5).

[0053] (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 it mirror-finish.

[0054] (C2) EBSD analysis is performed on the FIB-processed cross section using a field emission scanning electron microscope (FE-SEM) (product name: "SUPRA35VP", manufactured by Carl Zeiss) equipped with an electron backscatter diffraction (EBSD) device, 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 the thickness of layer 4 to be 90% or more. (Measurement conditions) Acceleration voltage: 15kV Current value: 1.8nA Irradiation current: 60 μm (with HC) Exp:Long 0.03s Binning: 8x8 WD: 15mm Tilt: 70° Step size: 0.02 μm BKD: Background Subtraction, Dynamic Background Subtraction, Normalize Intensity histogram Magnification: 20,000x Grain boundary definition: 15° or more

[0055] (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 Interation) and Grain CI Standardization. The CI value is calculated using the Voting method. Specifically, it is obtained by CI = (V1 - V2) / Videal (V1, 2:1, second solution, Videal: ideal solution).

[0056] (C4) The above EBSD analysis results were analyzed using commercially available software (product name: "OIM7.1", manufactured by TSL Solutions Co., Ltd.) and an IPF map (Inverse Pole) of the above analysis area was created. Figure A map (inverse pole-direction map) is created. In creating this IPF map, a grain boundary is defined when the azimuthal difference angle between adjacent measurement points is 15° or more. The IPF map shows the shape of each crystal grain.

[0057] (C5) Using the above software ("OMI7.1"), select any 30 TiCs within the IPF map of each analysis region. x N y The aspect ratio is measured for each crystal. x N y The aspect ratio of a crystal is TiC x Ny 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. 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 ratio of the crystals. In this disclosure, TiC in the IPF map of the analysis region x N y A crystal is a crystal with attached carbon 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.

[0058] As long as measurements are performed on the same sample, it has been confirmed that 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 the measurement is performed multiple times.

[0059] 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 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.

[0060] TiC x N y The crystal diameter can be measured using the following procedure (D1) to (D6).

[0061] (D1) Cutting tool 10 along the normal of the rake face of substrate 1 with a diamond wire, TiC x N y The cross-section of layer 4 is exposed. Ion milling with Ar ions is performed on the exposed cross-section to make it mirror-finish. 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 the straight line parallel to the thickness direction of layer 4 • Irradiation time: 6 hours

[0062] (D2) The cross-section in a mirror state is electrically world Emission type scanning electron microscope ( FE -Observe at 5000x magnification using SEM to obtain backscattered electron images (EBSD).

[0063] (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 coating 2. The measurement range is a rectangle with dimensions of (horizontal direction (parallel to the surface of coating 2): 30 μm) × (vertical direction (normal to the surface of coating 2): length including the entire coating 2).

[0064] (D4) Any one TiC within the measurement range x N y For 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 x N y Determine the average lateral diameter of the crystal.

[0065] (D5) Any 29 other TiCs within the measurement range x N y For each crystal, determine the average lateral diameter using the same method as in (D4) above.

[0066] (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.

[0067] 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.

[0068] <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 medium-speed machining of steel. 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.

[0069] 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 remove TiC x N y Layer 4 will be exposed and then measured using 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:

[0070] (Measurement conditions of nanoindentation) Indenter: Berkovich Load: 1 gf Loading time: 10 sec Holding time: 2 sec Unloading time: 10 sec

[0071] In addition, as long as the same TiC x N y layer is measured, it has been confirmed that even if the measurement points are changed and measured multiple times, there is almost no variation in the measurement results, and it is not arbitrary even if the measurement points are set arbitrarily.

[0072] <TiC x N y layer thickness> TiC x N y The thickness of the TiC x N y layer 4 may be 0.5 μm or more and 5 μm or less. As a result, in the coating 2, the TiC x N y layer 4 (in other words, the layer having high hardness) exists with a sufficient thickness, so that a cutting tool 10 having a more excellent tool life can be provided especially in medium-speed machining of steel. The thickness of the TiC x N y layer 4 may be 1 μm or more and 4 μm or less, or may be 1.5 μm or more and 3.5 μm or less.

[0073] ≪TiCNO layer≫ <Composition of TiCNO layer> In the present disclosure, the TiCNO layer 5 means a layer made of TiCNO. Here, "made of TiCNO" means that it may consist only of TiCNO, and in the range not impairing the effects of the present disclosure, it can contain inevitable impurities in addition to TiCNO. Examples of the inevitable impurities include chlorine (Cl) and the like. The total content rate of the inevitable impurities in the TiCNO layer 5 may be, for example, 0 mass% or more and 0.10 mass% or less, or may be 0.01 mass% or more and 0.05 mass% or less.

[0074] The content rate of TiCNO in the TiCNO layer 5 is specified by X-ray diffraction method (XRD) and energy dispersive X-ray analysis (EDX). The content rate of inevitable impurities in the TiCNO layer 5 is measured by secondary ion mass spectrometry (SIMS). Note that as long as it is measured in the same TiCNO layer 5, it has been confirmed that there is almost no variation in the measurement results even if the measurement location is arbitrarily selected.

[0075] <Thickness of TiCNO layer> The thickness of the TiCNO layer 5 may be 1 μm or less. Thereby, it becomes easier to suppress the peeling of the TiC x N y layer 4 (in other words, the layer having high hardness), and thus, it is possible to provide the cutting tool 10 having more excellent tool life especially in medium-speed machining of steel. The thickness of the TiCNO layer 5 may be 0.3 μm or more and 1 μm or less, may be 0.4 μm or more and 0.9 μm or less, or may be 0.5 μm or more and 0.8 μm or less.

[0076] ≪Other layers≫ Examples of other layers include an underlying layer (not shown), an intermediate layer (not shown), and a surface layer (not shown), etc. The underlying layer is the layer in contact with the base material 1. The surface layer is the layer located on the surface of the coating 2. The intermediate layer is the layer disposed between the underlying layer and the α-Al2O3 layer 3, the TiC x N y layer 4 and the surface layer, or when the above TiCNO layer 5 does not exist, it is the layer disposed between the α-Al2O3 layer 3 and the TiC x N y layer 4.

[0077] <Underlying layer> The base layer may consist of TiN or TiCN. "Composed 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 base 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.

[0078] 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.

[0079] 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.

[0080] <Middle class> 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.

[0081] 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.

[0082] 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.

[0083] <Surface layer> The surface layer may consist of TiN. "Consisting of TiN" means that it may consist only of TiN, or it may contain unavoidable impurities in addition to TiN. 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 surface layer may be, for example, 0% by mass or more and 1.0% by mass or less, or 0.1% by mass or more and 0.4% by mass or less.

[0084] The composition of the surface layer as TiN is determined by X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX). The content of unavoidable impurities in the surface layer is determined by secondary ion mass spectrometry (SIMS). It has been confirmed that, as long as measurements are taken on the same surface layer, there is almost no variation in the measurement results even if the measurement site is arbitrarily selected.

[0085] The thickness of the surface layer may be 0.5 μm or more and 3.0 μm or less, or 1.0 μm or more and 2.5 μm or less.

[0086] [Embodiment 2: Method for manufacturing a cutting tool] The method for manufacturing the cutting tool of this embodiment will be explained with reference to Figure 3. Figure 3 is a schematic cross-sectional view of an example of a CVD apparatus used in the manufacture of the cutting tool of this disclosure.

[0087] 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 comprises a seconda step of forming an α-Al2O3 layer by CVD and a 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 between the second a step and the second b step, in which a TiCNO layer is formed by CVD. Details of each step are described below.

[0088] ≪1st process≫ In the first step, the base material 1 is prepared. The base material 1 can be the base material 1 described in Embodiment 1.

[0089] 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.

[0090] ≪Second process≫ 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 3. The CVD apparatus 30 comprises a plurality of substrate set jigs 31 for holding the substrate 1, and a reaction vessel 32 made of heat-resistant alloy steel that covers the substrate set jigs 31. A temperature control device 33 is provided around the reaction vessel 32 to control the temperature inside 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 set 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 formed as follows: an α-Al2O3 layer, a TiCNO layer, and TiC x N y It can form layers.

[0091] If the coating includes the "other layer" described in Embodiment 1, the "other layer" can be formed by a conventionally known method.

[0092] <Step 2a: Process for forming an α-Al2O3 layer by CVD method> In step 2a, an α-Al2O3 layer is formed by the CVD method. 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, the raw material gas for the α-Al2O3 layer is introduced into the reaction vessel 32 from the gas introduction pipe 35. As a result, an α-Al2O3 layer is formed on the substrate 1, and a "first cutting tool precursor" with an α-Al2O3 layer formed on the substrate 1 is obtained.

[0093] A mixed gas of AlCl3, CO2, HCl, CO, H2S, and H2 is used as the raw material gas for the α-Al2O3 layer.

[0094] The AlCl3 content in the mixed gas may be between 2.0 atm% and 4.0 atm%. The CO2 content in the mixed gas may be between 1.0 atm% and 3.0 atm%. The HCl content in the mixed gas may be between 2.0 atm% and 6.0 atm%. The CO content in the mixed gas may be between 2.0 atm% and 3.0 atm%. The H2S content in the mixed gas may be between 0.1 atm% and 1.0 atm%.

[0095] 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. Furthermore, the gas introduction pipe 35 may be rotated when introducing the gas.

[0096] Regarding the above manufacturing method, the characteristics of the α-Al2O3 layer can be changed by controlling each condition of the CVD method. For example, the thickness of the α-Al2O3 layer can be controlled by adjusting the deposition time.

[0097] <Step 2c: Process for forming a TiCNO layer by CVD method> In step 2c, a TiCNO layer is formed by the CVD method. More specifically, first, a "first cutting tool precursor" with an α-Al2O3 layer formed on a substrate 1 is placed in a substrate set jig 31, and while controlling the temperature and pressure in the reaction vessel 32 within a predetermined range, a raw material gas for the TiCNO layer is introduced into the reaction vessel 32 from a gas introduction pipe 35. As a result, a TiCNO layer is formed on the α-Al2O3 layer, and a "first' cutting tool precursor" with a TiCNO layer formed on the α-Al2O3 layer is obtained.

[0098] A mixed gas of TiCl4, CH3CN, CO, N2, and H2 is used as the source gas for the TiCNO layer.

[0099] The TiCl4 content in the mixed gas may be between 0.5 atm% and 3.0 atm%. The CH3CN content in the mixed gas 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%. The N2 content in the mixed gas may be between 10 atm% and 40 atm%.

[0100] 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. Furthermore, the gas introduction pipe 35 may be rotated when introducing the gas.

[0101] Regarding the above manufacturing method, the characteristics of the TiCNO layer can be changed by controlling each condition of the CVD method. For example, the thickness of the TiCNO layer can be controlled by adjusting the deposition time.

[0102] <Step 2b: TiC by CVD method> x N y Layer formation process > In step 2b, TiC is processed by CVD. x N y A layer is formed. More specifically, if the second c step is not performed, first, the "first cutting tool precursor" on which an α-Al2O3 layer has been formed on the substrate 1 is placed on the substrate 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 allows TiC to form on the α-Al2O3 layer. x N y A layer is formed.

[0103] Furthermore, when step 2c is performed, first, the "1' cutting tool precursor," in which a TiCNO layer is formed on an α-Al2O3 layer, is placed in the substrate set jig 31, and while controlling the temperature and pressure in the reaction vessel 32 to a predetermined range, TiC x N yThe 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.

[0104] TiC x N y A mixed gas of TiCl4, CH3CN, CO, N2, and H2 is used as the raw material gas for the layer.

[0105] The CO content c1 in the mixed gas is between 0.15 atm% and 0.4 atm%. x N y The crystal diameter can be reduced while maintaining the columnar structure of the crystal. The TiCl4 content c3 in the mixed gas may be between 0.5 atm% and 3.0 atm%. The CH3CN content c4 in the mixed gas may be between 0.01 atm% and 3.0 atm%. The N2 content c2 in the mixed gas may be between 1 atm% and 40 atm%.

[0106] 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. Furthermore, the gas introduction pipe 35 may be rotated when introducing gas.

[0107] 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.

[0108] <Other processes> The second step may include surface treatment steps such as surface grinding and blasting, in addition to the steps described above.

[0109] Features of the manufacturing method for cutting tools according to this embodiment 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. As a result, the coating consists of an α-Al2O3 layer placed on the substrate 1 and a TiC layer placed on the α-Al2O3 layer. 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.

[0110] 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 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, when TiC is deposited on an α-Al2O3 layer... x N y When arranging layers, an α-Al2O3 layer is used. film deposition Because this process is carried out at high temperatures (for example, around 1000°C), TiC x N y The layer deposition could not be performed at low temperatures (e.g., around 800°C). Furthermore, due to the tendency for α-Al2O3 particles in the α-Al2O3 layer to become coarse, the TiC placed on the α-Al2O3 layer was not suitable. x N y TiC in the layer 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.

[0111] 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. 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. Therefore, the coating consists of an α-Al2O3 layer placed on the substrate 1 and TiC placed on the α-Al2O3 layer. 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 yThe 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% or more and 0.4 atm% or less, the ratio of the N2 content in the mixed gas to the CO content c1 in the mixed gas, c2 / c1, is 10 or more and 150 or less, the ratio of the N2 content in the mixed gas to the CH3CN content c4 in the mixed gas, c2 / c4, is 75 or less, and the ratio of the sum of the CO content c1, N2 content c2, CH3CN content c4, and H2 content c5 in the mixed gas (c1+c2+c4+c5) / c3 to the TiCl4 content c3 in the mixed gas is 49 or more and 99 or less. This allows the supply amounts of C atoms and N atoms to be appropriately changed, so that the values ​​of x and y can be adjusted to the desired range. The present inventors have discovered, through diligent research, that the cutting tool described herein can be realized by adopting such a manufacturing method. [Examples]

[0112] This embodiment will be described in more detail by reference to examples. However, this embodiment is not limited by these examples.

[0113] <<Manufacturing of cutting tools>> Cutting tools for samples 1-21 and 101-106 were fabricated as follows.

[0114] ≪1st process≫ 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 the base material) ·WC content: balance ·TaC content: 2.0% by mass ·NbC content: 1.0% by mass ·Co content: 10.0% by mass

[0115] ≪Second process≫ An α-Al2O3 layer was formed on the above substrate by CVD under the conditions described in Tables 1-1 and 1-2 (Step 2a). The deposition time was adjusted as appropriate so that the α-Al2O3 layer had the thickness described in Tables 4-1 and 4-2. Next, for samples 17-19 and sample 106, a TiCNO layer was formed on the above α-Al2O3 layer by CVD under the conditions described in Tables 2-1 and 2-2. The deposition time was adjusted as appropriate so that the TiCNO layer had the thickness described in Tables 4-1 and 4-2. Note that for sample 106, the conditions in Step 2c correspond to the deposition conditions of the "upper layer" of "Invention 1" shown in the example of Patent Document 2, except for the deposition time (i.e., the conditions that contribute to the thickness). Next, for samples 1-16, 20, 21, and 101-105, TiC was applied to the α-Al2O3 layer by CVD under the conditions described in Tables 3-1 and 3-2. 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 Tables 5-1 and 5-2. Regarding sample 105, the conditions in step 2b correspond to the film deposition conditions for the TiCN layer of sample 1 shown in the example of Patent Document 1, except for the film deposition time (i.e., the condition contributing to the thickness). Furthermore, for samples 17-19, TiC was deposited on the TiCNO layer by CVD under the conditions shown in Tables 3-1 and 3-2. x N y A layer was formed (step 2b). The film deposition time was TiC x N y The layers were adjusted as appropriate to have the thicknesses indicated in Tables 5-1 and 5-2. Note that if "-" is entered in all columns of Tables 2-1 and 2-2, it means that step 2c was not performed. Similarly, if "-" is entered in all columns of Table 3-2, it means that step 2b was not performed.

[0116] Based on the above, cutting tools were fabricated for samples 1-21 and 101-106. Regarding the TiCNO layer in sample 106, the TiCNO layer is composed of multiple TiC x N y It consists of O crystals, 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 being an O crystal, the x, y, aspect ratio, crystal diameter, and hardness were measured in the same manner as described in Embodiment 1.

[0117] [Table 1-1]

[0118] [Table 1-2]

[0119] [Table 2-1]

[0120] [Table 2-2]

[0121] [Table 3-1]

[0122] [Table 3-2]

[0123] [Table 4-1]

[0124] [Table 4-2]

[0125] [Table 5-1]

[0126] [Table 5-2]

[0127] [Table 6-1]

[0128] [Table 6-2]

[0129] ≪Evaluation of Cutting Tool Characteristics≫ <Composition of the α-Al2O3 layer> For each cutting tool related to a sample, the composition of the α-Al2O3 layer was determined by the method described in Embodiment 1. The obtained results are recorded in the "Composition" column of the "α-Al2O3 layer" column in Tables 4-1 and 4-2. In cases where a component name is listed in the "Composition" column of the "α-Al2O3 layer" column in Tables 4-1 and 4-2, it means that the α-Al2O3 layer consists of the component represented by that component name.

[0130] <Thickness of the α-Al2O3 layer> For each cutting tool used with a sample, the thickness of the α-Al2O3 layer was determined using the method described in Embodiment 1. The results obtained are recorded in the "Thickness [μm]" column of the "α-Al2O3 layer" column in Tables 4-1 and 4-2.

[0131] <Particle size of α-Al2O3 particles> For the cutting tools related to each sample, the particle size of the α-Al₂O₃ particles was determined by the method described in Embodiment 1. The obtained results are described in the "Particle Size [μm]" column of the "α-Al₂O₃ Layer" column in Tables 4-1 and 4-2.

[0132] <Composition of TiCNO Layer> For the cutting tools related to each sample, the composition of the TiCNO layer was determined by the method described in Embodiment 1. The obtained results are described in the "Composition" column of the "TiCNO Layer" column in Tables 4-1 and 4-2. In the case where a component name is described 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 the component name.

[0133] <Thickness of TiCNO Layer> For the cutting tools related to each sample, the thickness of the TiCNO layer was determined by the method described in Embodiment 1. The obtained results are described in the "Thickness [μm]" column of the "TiCNO Layer" column in Tables 4-1 and 4-2.

[0134] <TiC x N y <Composition of Layer> For the cutting tools related to each sample, for TiC x N y the composition of the layer was determined by the method described in Embodiment 1. The obtained results are described in the "Composition" column, "x" column, and "y" column of the "TiC x N y layer" column in Tables 5-1 and 5-2. In the case where a component name is described in the "Composition" column of the "TiC x N y layer" column in Tables 5-1 and 5-2, it means that the TiC x N y layer consists of the component represented by the component name.

[0135] <TiC x N y <Thickness of Layer> For the cutting tools related to each sample, for TiC x N yThe thickness of the layer was determined by the method described in Embodiment 1. The obtained results are recorded in the "Thickness [μm]" column of the "TiC x N y layer" column in Tables 5-1 and 5-2.

[0136] <TiC x N y crystal grain size> For the cutting tool related to each sample, the grain size of the TiC x N y crystal was determined by the method described in Embodiment 1. The obtained results are recorded in the "Particle size [μm]" column of the "TiC x N y layer" column in Tables 5-1 and 5-2 under the "TiC x N y crystal" column.

[0137] <TiC x N y crystal aspect ratio> For the cutting tool related to each sample, the aspect ratio of the TiC x N y crystal was determined by the method described in Embodiment 1. The obtained results are recorded in the "Aspect ratio" column of the "TiC x N y layer" column in Tables 5-1 and 5-2 under the "TiC x N y crystal" column.

[0138] ]><TiC x N y layer hardness> For the cutting tool related to each sample, the hardness of the TiC<' x N y layer was determined by the method described in Embodiment 1. The obtained results are recorded in the "Hardness [GPa]" column of the "TiC x N y layer" column in Tables 5-1 and 5-2.

[0139] <Coating thickness> For the cutting tool related to each sample, the coating thickness was determined by the method described in Embodiment 1. The obtained results are recorded in the "Thickness [μm]" column of the "Coating" column in Tables 6-1 and 6-2.

[0140] Cutting Test Using the cutting tool for each sample, machining was performed under the following cutting conditions, and the amount of coating wear [mm] on the flank surface was measured every minute of cutting time. The time when the amount of wear exceeded 0.2 mm was recorded as 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) ·Work material: SCM440 (HB=300) ·Cutting speed: 250m / min Feed rate: 0.3mm / rev • Cutting depth: 2.0 mm • Water-soluble cutting fluid: Yes (wet type) The cutting conditions described above correspond to the cutting conditions for medium-speed machining of steel.

[0141] 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 of medium-speed machining of steel.

[0142] The cutting tools for samples 1 to 21 are examples. The cutting tools for samples 101 to 106 are 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 21 have superior tool life compared to the cutting tools for samples 101 to 106, especially in medium-speed machining of steel.

[0143] Based on the above, it was found that the cutting tools related to samples 1 to 21 have excellent tool life, especially in medium-speed machining of steel.

[0144] As described above, the embodiments and examples of this disclosure have been explained, but it is also intended from the outset that the configurations of each of the embodiments and examples described above may be combined as appropriate or modified in various ways.

[0145] 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. [Explanation of Symbols]

[0146] 1 base material, 2 coating, 3 α-Al2O3 layer, 4 TiC x N y Layers, 5 TiCNO layers, 10 cutting tools, 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 base material and a coating disposed on the base material, The coating is α-Al disposed on the substrate. ２ O ３ The layer and the α-Al ２ O ３ TiC arranged in layers ｘ N ｙ Includes layers, The above x and y satisfy the relationship between Equation 1 and Equation 2, 0.7≦x+y≦1.3 Formula 1 y≦1.5x Formula 2 The above TiC ｘ N ｙ layer consists of a plurality of TiC ｘ N ｙ crystals, and The TiC ｘ N ｙ The crystals are columnar crystals that extend along the direction from the substrate to the surface of the coating. The TiC ｘ N ｙ A cutting tool in which the crystal diameter is between 0.05 μm and 0.5 μm.

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 It consists of particles, The α-Al ２ O ３ The cutting tool according to claim 1 or claim 2, wherein the particle size is 0.3 μm or more and 1.0 μm or less.

5. The aforementioned 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 It further includes a TiCNO layer positioned in contact with the layer, The cutting tool according to claim 1 or claim 2, wherein the thickness of the TiCNO layer is 1 μm or less.

6. The cutting tool according to claim 1 or claim 2, wherein x and y further satisfy the relationship in equation 3. y < 1.5x Equation 3

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