Cutting tool and method of manufacturing the same

Abstract

A cutting tool includes a base material and a coating film provided on the base material, wherein the coating film has a hard particle layer composed of hard particles, the hard particles include a multilayer structure in which first unit layers and second unit layers are alternately stacked, the first unit layers are composed of a first compound having a cubic crystal structure, the second unit layers are composed of a second compound having a cubic crystal structure, the first compound and the second compound are each composed of: one or more metal elements selected from the group consisting of elements of Group 4, Group 5, and Group 6 of the periodic table; silicon; and one or more elements selected from the group consisting of carbon, nitrogen, boron, and oxygen, and a percentage of the number of atoms of the silicon in the first unit layers with respect to the total number of atoms of the metal elements and the silicon is different from a percentage of the number of atoms of the silicon in the second unit layers with respect to the total number of atoms of the metal elements and the silicon.

Description

Technical Field

[0001] This disclosure relates to cutting tools and methods for manufacturing the same. This application claims priority to Japanese Patent Application No. 2021-078030, filed April 30, 2021. The entire contents of that Japanese patent application are incorporated herein by reference. Background Technology

[0002] In the past, in order to improve the wear resistance of cutting tools, cutting tools with TiSiCN films formed on the substrate were developed.

[0003] Patent document 1 discloses a nanocomposite coating comprising TiC fabricated by thermal CVD. x N 1-x Nanocrystalline layers and amorphous SiC x N y The second phase.

[0004] Patent document 2 discloses a nanocomposite layer of at least one layer, comprising a first nanocrystalline phase composed of cubic titanium oxycarbonitride manufactured by thermal CVD and a second amorphous phase composed of silicon oxycarbonitride or silicon oxycarbide.

[0005] Non-patent document 1 discloses a TiSiCN coating composed of a nanocomposite structure formed by PVD.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Publication No. 2015-505902

[0009] Patent Document 2: Japanese Patent Publication No. 2020-507679

[0010] Non-patent literature

[0011] Non-patent document 1: Shinya Imamura et al., "Properties and cutting performance of AlTiCrN / TiSiCN bilayer coatings deposited by cathodic-arc ion plating", Surface and Coatings Technology, 202, (2007), 820-825 Summary of the Invention

[0012] The cutting tool disclosed herein comprises a substrate and a coating disposed on said substrate, wherein,

[0013] The coating has a hard particle layer composed of hard particles.

[0014] The hard particles comprise a multi-layered structure consisting of alternating layers of first and second unit layers.

[0015] The first unit layer is composed of a first compound having a cubic crystal structure.

[0016] The second unit layer is composed of a second compound having a cubic crystal structure.

[0017] The first compound and the second compound are each composed of the following elements:

[0018] Choose one or more metallic elements from the group consisting of Group 4, Group 5 and Group 6 elements of the periodic table;

[0019] Silicon; and

[0020] Choose one or more elements from the group consisting of carbon, nitrogen, boron, and oxygen.

[0021] The percentage of the number of silicon atoms in the first unit layer relative to the total number of the metal elements and the number of silicon atoms is different from the percentage of the number of silicon atoms in the second unit layer relative to the total number of the metal elements and the number of silicon atoms.

[0022] The method for manufacturing the cutting tool disclosed herein is the method for manufacturing the cutting tool described above, wherein,

[0023] The method for manufacturing the cutting tool includes:

[0024] The first step involves preparing the substrate; and

[0025] In the second step, a coating is formed on the substrate to obtain the cutting tool.

[0026] The second step includes a second step, step 2a, which forms a hard particle layer composed of hard particles by CVD.

[0027] The second step includes a second step (2a-1) in which a first raw material gas, a second raw material gas, and a third raw material gas are sprayed toward the surface of the substrate.

[0028] The first raw material gas contains one or more elements selected from the group consisting of Group 4, Group 5, and Group 6 elements of the periodic table.

[0029] The second raw material gas is SiCl4.

[0030] The third raw material gas contains one or more elements selected from the group consisting of carbon, nitrogen, boron, and oxygen.

[0031] The first raw material gas is ejected from a plurality of first injection holes disposed in the nozzle.

[0032] The second raw material gas is ejected from a plurality of second injection holes disposed in the nozzle.

[0033] The third raw material gas is ejected from a plurality of third injection holes disposed in the nozzle.

[0034] In the 2a-1 step, the nozzle rotates.

[0035] The plurality of second injection holes include a second-1 injection hole and a second-2 injection hole.

[0036] The diameter r1 of the second-1 injection hole is different from the diameter r2 of the second-2 injection hole. Attached Figure Description

[0037] Figure 1 This is a schematic diagram showing an example of a cross-section of the cutting tool according to Embodiment 1.

[0038] Figure 2 This is a schematic diagram showing another example of a cross-section of the cutting tool involved in Embodiment 1.

[0039] Figure 3 This is a schematic diagram showing another example of a cross-section of the cutting tool involved in Embodiment 1.

[0040] Figure 4 This is a schematic diagram showing another example of a cross-section of the cutting tool involved in Embodiment 1.

[0041] Figure 5 It is a bright-field scanning electron microscope (BF-SEM) image of the cross-section of the hard phase particle layer of the cutting tool according to Embodiment 1.

[0042] Figure 6 Is Figure 5 Electron diffraction image taken in region A shown.

[0043] Figure 7 A represents the number of silicon atoms. Si The number of atoms A relative to the metallic element (titanium) M And the number of silicon atoms A Si The total percentage {A} Si / (A Si +A M )}×100 along Figure 5 The chart shows the change in the direction of the arrows.

[0044] Figure 8 Yes Figure 5 The Fourier transform image obtained by performing a Fourier transform on region A shown.

[0045] Figure 9 It means Figure 8 A graph showing the intensity distribution within the four corner boxes of the Fourier transform image.

[0046] Figure 10 This is a schematic cross-sectional view of an example of a CVD apparatus used in the manufacture of the cutting tool according to Embodiment 2. Detailed Implementation

[0047] [The problem this disclosure aims to solve]

[0048] In recent years, the requirements for improving tool life have been increasing, especially in the milling of high-hardness heat-resistant stainless steel, where further improvements in tool life are required.

[0049] Therefore, the purpose of this disclosure is to provide a cutting tool that can have a long tool life even in milling of high-hardness heat-resistant stainless steel.

[0050] [The Effects of This Disclosure]

[0051] According to this disclosure, a cutting tool with a long tool life can be provided even in milling of high-hardness heat-resistant stainless steel.

[0052] [Description of embodiments of this disclosure]

[0053] The embodiments of this disclosure are first described by listing them.

[0054] (1) The cutting tool of this disclosure comprises a substrate and a coating disposed on the substrate, wherein,

[0055] The coating has a hard particle layer composed of hard particles.

[0056] The hard particles comprise a multi-layered structure consisting of alternating layers of first and second unit layers.

[0057] The first unit layer is composed of a first compound having a cubic crystal structure.

[0058] The second unit layer is composed of a second compound having a cubic crystal structure.

[0059] The first compound and the second compound are each composed of the following elements:

[0060] Choose one or more metallic elements from the group consisting of Group 4, Group 5 and Group 6 elements of the periodic table;

[0061] Silicon; and

[0062] Choose one or more elements from the group consisting of carbon, nitrogen, boron, and oxygen.

[0063] The percentage of the number of silicon atoms in the first unit layer relative to the total number of the metal elements and the number of silicon atoms is different from the percentage of the number of silicon atoms in the second unit layer relative to the total number of the metal elements and the number of silicon atoms.

[0064] According to this disclosure, a cutting tool with a long tool life can be provided even in milling of high-hardness heat-resistant stainless steel.

[0065] (2) Preferably, the first unit layer and the second unit layer have the same crystal orientation. This minimizes the interfacial energy, and the hardness does not easily decrease even when exposed to high-temperature environments.

[0066] (3) Preferably, in the first unit layer and the second unit layer, the percentage of the number of silicon atoms relative to the total number of the metal elements and the number of silicon atoms is 0.5% or more and 10% or less, respectively. This improves the heat crack resistance of the coating and the adhesion between the hard particle layer and adjacent layers in a balanced manner.

[0067] (4) Preferably, the thickness of the hard particle layer is more than 3 μm and less than 15 μm.

[0068] The thickness of the coating is greater than 3 μm and less than 30 μm.

[0069] This results in a balanced improvement in the abrasion resistance and damage resistance of the coating.

[0070] (5) Preferably, the number of silicon atoms A in the first unit layer Si Relative to the number of atoms A of the metallic element M And the number of atoms A of silicon Si The total percentage {A} Si / (A Si +A M )}×100, and the number of silicon atoms A in the second unit layer Si Relative to the number of atoms A of the metallic element M And the number of atoms A of silicon Si The total percentage {A} Si / (A Si +A MThe difference between 0.5% and 100 is greater than 0.5% and less than 10%. As a result, the hardness of the coating is increased.

[0071] (6) Preferably, the coating includes a base layer disposed between the substrate and the rigid particle layer.

[0072] The base layer is composed of a third compound.

[0073] The third compound is composed of the following elements:

[0074] Choose one or more elements from the group consisting of Group 4, Group 5, Group 6 elements, and aluminum in the periodic table; and

[0075] Choose one or more elements from the group consisting of carbon, nitrogen, boron, and oxygen.

[0076] As a result, the adhesion between the coating and the substrate is improved, and the wear resistance is also improved.

[0077] (7) Preferably, the coating comprises a base layer disposed directly above the substrate.

[0078] The substrate layer is composed of at least one selected from the group consisting of TiN layer, TiC layer, TiCN layer, TiBN layer and Al2O3 layer.

[0079] By placing TiN, TiC, TiCN, or TiBN layers directly above the substrate as a base layer, the adhesion between the substrate and the coating can be improved. Furthermore, using an Al2O3 layer as a base layer can enhance the oxidation resistance of the coating.

[0080] (8) Preferably, the coating has a surface layer disposed on its outermost surface.

[0081] The surface layer is composed of a fourth compound.

[0082] The fourth compound is composed of the following elements:

[0083] Choose one or more elements from the group consisting of Group 4, Group 5, Group 6 elements, and aluminum in the periodic table; and

[0084] Choose one or more elements from the group consisting of carbon, nitrogen, boron, and oxygen.

[0085] As a result, the coating's resistance to heat cracking and its abrasion resistance are improved.

[0086] (9) Preferably, the coating has an intermediate layer disposed between the base layer and the hard particle layer. This improves the wear resistance of the coating.

[0087] (10) The method for manufacturing the cutting tool disclosed herein is the method for manufacturing the cutting tool described above, wherein,

[0088] The method for manufacturing the cutting tool includes:

[0089] The first step involves preparing the substrate; and

[0090] In the second step, a coating is formed on the substrate to obtain the cutting tool.

[0091] The second step includes a second step, step 2a, which forms a hard particle layer composed of hard particles by CVD.

[0092] The second step includes a second step (2a-1) in which a first raw material gas, a second raw material gas, and a third raw material gas are sprayed toward the surface of the substrate.

[0093] The first raw material gas contains one or more elements selected from the group consisting of Group 4, Group 5, and Group 6 elements of the periodic table.

[0094] The second raw material gas is SiCl4.

[0095] The third raw material gas contains one or more elements selected from the group consisting of carbon, nitrogen, boron, and oxygen.

[0096] The first raw material gas is ejected from a plurality of first injection holes disposed in the nozzle.

[0097] The second raw material gas is ejected from a plurality of second injection holes disposed in the nozzle.

[0098] The third raw material gas is ejected from a plurality of third injection holes disposed in the nozzle.

[0099] In the 2a-1 step, the nozzle rotates.

[0100] The plurality of second injection holes include a second-1 injection hole and a second-2 injection hole.

[0101] The diameter r1 of the second-1 injection hole is different from the diameter r2 of the second-2 injection hole.

[0102] According to this disclosure, a cutting tool with a long tool life can be provided even in milling of high-hardness heat-resistant stainless steel.

[0103] [Details of the embodiments disclosed herein]

[0104] The inventors of this invention, in developing a cutting tool that has a long tool life even in milling high-hardness heat-resistant stainless steel, used conventional cutting tools to mill high-hardness heat-resistant stainless steel and observed the damage state of the tools.

[0105] It was confirmed that during milling of high-hardness, heat-resistant stainless steel using the tools described in Patent Documents 1 and 2, thermal cracking occurred at the interface between the nanocomposite coating or nanocomposite material coating and the substrate due to the thermal load during machining, resulting in interfacial delamination. It is speculated that this is due to insufficient integration at the interface between the crystalline substrate and the nanocomposite coating or nanocomposite material coating.

[0106] Self-destruction of the TiSiCN coating was confirmed when milling high-hardness heat-resistant stainless steel using the tools described in Non-Patent Document 1. It is speculated that this is because the TiSiCN coating is formed using the PVD method, resulting in high compressive residual stress in the TiSiCN coating.

[0107] Based on the above insights, the inventors of this invention conducted in-depth research and obtained a cutting tool with a long tool life even in milling high-hardness, heat-resistant stainless steel. Hereinafter, specific examples of the cutting tool and its manufacturing method according to this disclosure will be described with reference to the accompanying drawings. In the drawings of this disclosure, the same reference numerals denote the same or equivalent parts. 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.

[0108] In this specification, expressions such as "A~B" refer to the upper and lower limits of a range (i.e., above A and below B). If no unit is recorded in A but only in B, the unit of A is the same as the unit of B.

[0109] In this specification, when compounds are represented by chemical formulas, all conventionally known atomic ratios are included unless otherwise specified, and are not necessarily limited to atomic ratios within the stoichiometric range. For example, when referred to as "TiSiCN", the ratio of the number of atoms constituting TiSiCN includes all conventionally known atomic ratios.

[0110] In this disclosure, when more than one value is recorded as both the lower and upper limits of a numerical range, combinations of any value recorded in the lower limit and any value recorded in the upper limit are also disclosed. For example, when a1 or higher, b1 or higher, and c1 or higher are recorded as the lower limit, and a2 or lower, b2 or lower, and c2 or lower are recorded as the upper limit, the following combinations are disclosed: a1 or higher and a2 or lower, a1 or higher and b2 or lower, a1 or higher and c2 or lower, b1 or higher and a2 or lower, b1 or higher and b2 or lower, b1 or higher and c2 or lower, c1 or higher and a2 or lower, c1 or higher and b2 or lower, and c1 or higher and c2 or lower.

[0111] [Implementation Method 1: Cutting Tool]

[0112] One embodiment of this disclosure (hereinafter also referred to as "this embodiment") includes a cutting tool comprising a substrate and a coating disposed on the substrate, wherein,

[0113] The coating has a hard particle layer composed of hard particles.

[0114] The hard particles comprise a multi-layered structure consisting of alternating layers of first and second unit layers.

[0115] The first unit layer is composed of a first compound having a cubic crystal structure.

[0116] The second unit layer is composed of a second compound having a cubic crystal structure.

[0117] The first compound and the second compound are each composed of the following elements:

[0118] Choose one or more metallic elements from the group consisting of Group 4, Group 5 and Group 6 elements of the periodic table;

[0119] Silicon; and

[0120] Choose one or more elements from the group consisting of carbon, nitrogen, boron, and oxygen.

[0121] The percentage of the number of silicon atoms in the first unit layer relative to the total number of atoms of the metal element and the silicon atoms is different from the percentage of the number of silicon atoms in the second unit layer relative to the total number of atoms of the metal element and the silicon atoms.

[0122] In this specification, the elements in Group 4 of the periodic table include titanium (Ti), zirconium (Zr) and hafnium (Hf), the elements in Group 5 include vanadium (V), niobium (Nb) and tantalum (Ta), and the elements in Group 6 include chromium (Cr), molybdenum (Mo) and tungsten (W).

[0123] The cutting tool of this embodiment can have a long tool life even in milling of high-hardness heat-resistant stainless steel. The reason for this is not yet clear, but it is speculated as described in (i) to (iii) below.

[0124] (i) In the cutting tool of this embodiment, the coating comprises a hard particle layer composed of hard particles. This hard particle layer may have regions composed of granular structures in its thickness direction. Therefore, the toughness of the hard particle layer is improved, and even if thermal cracking associated with cutting occurs on the surface of the coating, the propagation of cracks into the substrate is effectively suppressed. Furthermore, even when the coating comprises layers other than the hard particle layer, the difference in crystallinity between the hard particle layer and other layers can be reduced, thus suppressing the propagation of cracks at the interface between the hard particle layer and other layers, and suppressing film peeling. Therefore, the cutting tool can have a longer tool life.

[0125] (ii) In the cutting tool of this embodiment, the hard particles comprise a multilayer structure consisting of alternating layers of first and second unit layers with different compositions. Therefore, even if strain occurs within the hard particles, causing cracks associated with cutting on the surface of the coating, the propagation of these cracks into the substrate can be effectively suppressed. Furthermore, the increased hardness of the hard particles and the hard particle layers improves the wear resistance of the cutting tool. Additionally, the cutting tool can thus have a longer tool life.

[0126] (iii) In the cutting tool of this embodiment, the first compound and the second compound each have a cubic crystal structure and are composed of the following elements:

[0127] Choose one or more metallic elements from the group consisting of Group 4, Group 5 and Group 6 elements of the periodic table;

[0128] Silicon; and

[0129] Choose one or more elements from the group consisting of carbon, nitrogen, boron, and oxygen.

[0130] Both the first and second compounds mentioned above have high hardness. Therefore, the hard particle layer containing the first and second compounds has high hardness and excellent wear resistance. Consequently, the cutting tool can have a longer tool life.

[0131] <Cutting Tools>

[0132] like Figure 1 As shown, the cutting tool 1 of this embodiment includes a substrate 10 and a coating 15 disposed on the substrate 10. Figure 1The diagram illustrates a case where the coating 15 consists solely of a hard particle layer 11. Preferably, the coating 15 covers at least a portion of the cutting area of ​​the substrate, and more preferably, covers the entire surface of the substrate. The cutting area refers to the region on the substrate surface within 500 μm of the blade tip edge. Even if a portion of the substrate is not covered by the coating or the composition of the coating differs locally, this does not depart from the scope of this disclosure.

[0133] Types of cutting tools

[0134] The cutting tools disclosed herein may be, for example, drill bits, end mills (e.g., ball end mills), indexable cutting inserts for drill bits, indexable cutting inserts for end mills, indexable cutting inserts for milling, indexable cutting inserts for turning, metalworking saws, gear cutting tools, reamers, taps, etc.

[0135] <Substrate>

[0136] The substrate 10 includes a rake face and a flank face. Any conventionally known substrate can be used as such a substrate. For example, it is preferably a cemented carbide (e.g., a WC-based cemented carbide containing tungsten carbide and cobalt, which may contain carbonitrides such as Ti, Ta, and Nb), a cermet (with TiC, TiN, TiCN, etc. as the main components), a high-speed steel, a ceramic (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, alumina, etc.), a cubic boron nitride sintered body, or a diamond sintered body.

[0137] Among these various substrates, a substrate composed of a cemented carbide containing tungsten carbide and cobalt is preferred, wherein the cobalt content in the cemented carbide is 6% by mass or more and 11% by mass or less. This results in an excellent balance between hardness and strength at high temperatures, giving the substrate excellent properties for cutting tools used in the aforementioned applications. When using a WC-based cemented carbide as the substrate, its microstructure may include free carbon and an anomalous layer referred to as the η phase or ε phase.

[0138] Furthermore, the surface of the substrate can be modified. For example, in the case of cemented carbide, a de-β layer can be formed on its surface, and in the case of cermet, a surface-hardened layer can be formed. The substrate exhibits the desired effect even after its surface has been modified.

[0139] When the cutting tool is an indexable cutting insert, the substrate may or may not have a chip breaker. The shape of the tool tip edge can be any of the following: a sharp edge (the edge where the rake face and flank face intersect), honing (giving the sharp edge a rounded corner), a negative cutting edge (beveling), or a combination of honing and a negative cutting edge.

[0140] <Lamination>

[0141] (Composition of the coating)

[0142] The coating in this embodiment includes a hard particle layer. The coating in this embodiment only needs to include a hard particle layer, but it may also include other layers.

[0143] For example, such as Figure 2 As shown in the cutting tool 21, the coating 25 may also include a base layer 12 disposed between the substrate 10 and the hard particle layer 11, in addition to the hard particle layer 11.

[0144] like Figure 3 As shown in the cutting tool 31, the coating 35 may also include a surface layer 13 disposed on the hard particle layer 11, in addition to the hard particle layer 11 and the base layer 12.

[0145] like Figure 4 As shown in the cutting tool 41, the coating 45 may also include an intermediate layer 14 disposed between the base layer 12 and the hard particle layer 11, in addition to the hard particle layer 11, the base layer 12, and the surface layer 13.

[0146] Details about the hard granular layer, base layer, intermediate layer, and surface layer will be described later.

[0147] (Thickness of the coating)

[0148] In this embodiment, the thickness of the coating is preferably 3 μm or more and 30 μm or less. Here, the thickness of the coating refers to the overall thickness of the coating. When the overall thickness of the coating is 3 μm or more, it exhibits excellent wear resistance. On the other hand, when the overall thickness of the coating is 30 μm or less, peeling or damage to the coating can be suppressed during machining when significant stress is applied between the coating and the substrate. From the viewpoint of improving wear resistance, the lower limit of the overall thickness of the coating is more preferably 5 μm or more, and even more preferably 10 μm or more. From the viewpoint of suppressing peeling or damage to the coating, the upper limit of the overall thickness of the coating is more preferably 25 μm or less, and even more preferably 20 μm or less. The overall thickness of the coating is more preferably 5 μm or more and 25 μm or less, and even more preferably 10 μm or more and 20 μm or less.

[0149] The thickness of the aforementioned coating is measured, for example, by observing a cross-sectional sample parallel to the normal direction of the substrate surface using a scanning transmission electron microscope (STEM). This cross-sectional sample is a thin sheet sample processed using an ion slicer or similar device. An example of a scanning transmission electron microscope is the JEM-2100F (trademark) manufactured by Nippon Electron Ltd. The measurement conditions are set to an accelerating voltage of 200 kV and a current of 0.3 nA.

[0150] When "thickness" is mentioned in this specification, it refers to the average thickness. Specifically, the magnification of the cross-sectional sample is set to 10,000x. A rectangular measurement field of view (100 μm in the direction parallel to the substrate surface) × (the distance including the entire thickness of the coating) is set in the electron microscope image. The thickness amplitude at ten locations within this field of view is measured, and the average value is taken as the "thickness". The thickness (average thickness) of each layer described below is also measured and calculated in the same way.

[0151] It was confirmed that as long as the measurement is performed on the same sample, even if the measurement field of view is changed and the measurement is performed multiple times, the measurement results will have almost no deviation. Even if the measurement field of view is set arbitrarily, the results will not change arbitrarily.

[0152] <Hard granular layer>

[0153] (Composition of the hard granular layer)

[0154] The hard particle layer in this embodiment is composed of hard particles, which include a multilayer structure formed by alternating layers of first unit layers and second unit layers.

[0155] Even if the hard particle layer of this embodiment contains components other than hard particles, such as amorphous phases or intermetallic compounds (e.g., TiSi2, Co2Si, etc.) as unavoidable impurities, it does not depart from the scope of this disclosure as long as it achieves the effects of this disclosure.

[0156] (Thickness of the hard particle layer)

[0157] In this embodiment, the thickness of the hard particle layer is preferably 3 μm or more and 15 μm or less. When the thickness of the hard particle layer is 3 μm or more, it exhibits excellent wear resistance. On the other hand, when the thickness of the hard particle layer is 15 μm or less, during machining, it is possible to suppress the peeling or damage of the coating when large stress is applied between the coating and the substrate. From the viewpoint of improving wear resistance, the lower limit of the thickness of the hard particle layer is more preferably 4 μm or more, and even more preferably 5 μm or more. From the viewpoint of suppressing the peeling or damage of the coating, the upper limit of the thickness of the hard particle layer is preferably 15 μm or less, and even more preferably 10 μm or less. The thickness of the hard particle layer is more preferably 4 μm or more and 15 μm or less, and even more preferably 5 μm or more and 10 μm or less.

[0158] The first unit layer consists of a first compound having a cubic crystal structure. The second unit layer consists of a second compound having a cubic crystal structure. If both the first and second compounds have a cubic crystal structure, they exhibit excellent wear resistance and can also achieve high toughness. The cubic crystal structure of the first and second compounds can be confirmed through pattern analysis based on confined field-of-view electron diffraction.

[0159] The first compound and the second compound are each composed of the following elements:

[0160] Choose one or more metallic elements from the group consisting of Group 4, Group 5 and Group 6 elements of the periodic table;

[0161] Silicon; and

[0162] Choose one or more elements from the group consisting of carbon, nitrogen, boron, and oxygen.

[0163] Here, the composition of the first compound differs from that of the second compound. More specifically, the percentage of silicon atoms in the first compound relative to the total number of metal elements and silicon atoms differs from the percentage of silicon atoms in the second compound relative to the total number of metal elements and silicon atoms.

[0164] Even if the first and second compounds of this embodiment contain unavoidable impurities, they do not depart from the scope of this disclosure as long as they achieve the effects of this disclosure.

[0165] Examples of the first and second compounds include TiSiC, TiSiN, TiSiCN, TiSiNO, TiSiCNO, TiSiBN, TiSiBNO, TiSiCBN, ZrSiC, ZrSiO2, HfSiC, HfSiN, TiCrSiN, TiZrSiN, CrSiN, VSiN, ZrSiCN, ZrSiCNO, ZrSiN, NbSiC, NbSiN, and NbSiCN. Furthermore, the presence of unavoidable impurities in the first and second compounds does not depart from the scope of this disclosure.

[0166] The fact that hard particles contain a multilayer structure consisting of alternating layers of first and second unit layers can be confirmed by the following methods (A1) to (A6).

[0167] (A1) A diamond wire is used to cut along the normal of the substrate using a cutting tool to expose the profile of the hard granular layer. The exposed profile is then subjected to focused ion beam processing (hereinafter also referred to as "FIB processing") to make the profile a mirror finish.

[0168] (A2) The cross-section after FIB processing was observed using bright-field scanning electron microscopy (BF-SEM) to identify a hard particle. Then, a BE-STEM image of the identified hard particle was obtained. Figure 5 This is an example of a BF-STEM image showing a hard particle in the cutting tool of this embodiment.

[0169] (A3) In the above BF-STEM image, the measurement area (size: 100nm × 100nm) is set up such that it includes a region with 10 or more layers of both white and black layers stacked together. Figure 5 In the diagram, the square area enclosed by the white border corresponds to the measurement area.

[0170] In addition, Figure 5 In the diagram, the black layer represents areas with high silicon content, while the white layer represents areas with low silicon content.

[0171] (A4) Within the measurement area of ​​the aforementioned BF-STEM image, determine the stacking orientation of the white layer (hereinafter also referred to as the "white layer") and the black layer (hereinafter also referred to as the "black layer"). Specifically, overlap the electron diffraction pattern of the restricted field of view with the stacking orientation of the white and black layers, and determine the stacking orientation based on the orientation indicated by the diffraction spots. Figure 5 The electron diffraction image taken in region A is shown in... Figure 6 .exist Figure 5 In the image, the stacking direction is indicated by a white arrow.

[0172] (A5) In the measurement area of ​​the above BF-STEM image, along the stacking direction, line analysis was performed using EDX (Energy Dispersive X-ray Spectroscopy) with attached SEM to determine the composition. The beam diameter for line analysis was set to less than 0.5 nm, the scanning interval was set to 0.5 nm, and the length of line analysis was set to 50 nm.

[0173] (A6) If the results of the online analysis meet the following conditions (a1) to (a2), it is confirmed that the hard particles contain a multilayer structure consisting of alternating layers of first and second unit layers.

[0174] (a1) The measurement area includes one or more metallic elements selected from the group consisting of elements from Group 4, Group 5 and Group 6 of the periodic table, silicon, and one or more elements selected from the group consisting of carbon, nitrogen, boron and oxygen.

[0175] (a2) Create a graph to display the results of the line analysis on a coordinate system, in which the X-axis is the distance from the starting point of the measurement, and the Y-axis is the number of silicon atoms A. Si Relative to the number of atoms A of the metallic element M And the number of atoms A of silicon Si The total percentage {A} Si / (A Si +A M )}×100. In this chart, calculate {A} in the measurement area. Si / (A Si +A M The average of )}×100 (hereinafter also referred to as "average"). As the distance from the starting point of the measurement increases, {A} alternately exists. Si / (A Si +A M The regions that are larger than the average and the regions that are smaller than the average are )}×100.

[0176] Figure 7 This is an example of the above diagram in this embodiment. Figure 7 A represents the number of silicon atoms. Si The number of atoms A relative to the metallic element (titanium) M And the number of atoms A of silicon Si The total percentage {A} Si / (A Si +A M A graph showing the change along the arrow direction () x 100. Figure 7 In the diagram, the X-axis represents the distance from the starting point of the measurement along the direction of the arrow, and the Y-axis represents {A}. Si / (A Si +A M )}×100. In Figure 7 In the diagram, the dashed line L1 represents {A} in the measurement area. Si / (A Si +A M The average of )}×100.

[0177] exist Figure 7 In the process, as the distance from the starting point of the measurement increases, {A} alternately exists. Si / (A Si +A M The regions S1 and S2 are larger than the above average value and smaller than the above average value, respectively. Therefore, in Figure 5 The hard particles shown are confirmed to contain a multilayer structure consisting of alternating layers of first and second unit layers.

[0178] It was confirmed that as long as the measurement is performed on the same sample, even if the hard particles determined in (A2) are changed and the measurement is performed multiple times, the measurement results are almost without deviation, and the results will not change arbitrarily even if the measurement site is set arbitrarily.

[0179] Once it is confirmed by the above method that the hard particles contain a multi-layered structure consisting of alternating layers of first and second unit layers, the effects of this disclosure are confirmed.

[0180] For ease of understanding, the phrase "{A in the measurement area" in (a2) above will be used hereafter. Si / (A Si +A M )}×100 ratio {A Si / (A Si +A M The area with an average value of 100 is designated as the "first unit layer". The area within the measurement region containing {A} is then defined as the "largest area". Si / (A Si +A M )}×100 ratio {A Si / (A Si +A M The smaller region with an average value of 100 is denoted as the "second unit layer".

[0181] (Composition of the first and second unit layers)

[0182] In the first unit layer and the second unit layer, the number of silicon atoms A Si Relative to the number of atoms A of the metallic element M With the number of atoms A of silicon Si The total percentage {A} Si / (A Si +A M The percentages of {A}×100 are preferably 0.5% or more and 10% or less. This improves the heat crack resistance of the hard particle layer and the adhesion between the hard particle layer and adjacent layers in a balanced manner. The {A} of the first unit layer and the second unit layer are respectively... Si / (A Si +A M The lower limit of {A}×100 is preferably 0.5% or more, preferably 0.7% or more, preferably 1.0% or more, and preferably 1.2% or more. The respective {A} of the first unit layer and the second unit layer... Si / (A Si +A M The upper limit of {A}×100 is preferably 10.0% or less, preferably 8.0% or less, preferably 7.2% or less, preferably 7% or less, and preferably 5% or less. The respective {A} of the first unit layer and the second unit layer Si / (A Si +AM The content of 100 is preferably 0.5% or more and 8.0% or less, preferably 0.5% or more and 7.2% or less, preferably 0.7% or more and 7% or less, and preferably 1.0% or more and 5.0% or less.

[0183] The number of silicon atoms A in the first unit layer Si Relative to the number of atoms A of the metallic element M And the number of atoms A of silicon Si The total percentage {A} Si / (A Si +A M The lower limit of )}×100 is preferably 1% or more, preferably 1.5% or more, preferably 2.0% or more, preferably 5.3% or more, and preferably 6.0% or more. The number of silicon atoms A in the first unit layer. Si Relative to the number of atoms A of the metallic element M And the number of atoms A of silicon Si The total percentage {A} Si / (A Si +A M The upper limit of )}×100 is preferably 10.0% or less, preferably 9.0% or less, and preferably 8.0% or less. From the viewpoint of improving heat resistance, the number of silicon atoms A in the first unit layer Si Relative to the number of atoms A of the metallic element M And the number of atoms A of silicon Si The total percentage {A} Si / (A Si +A M The percentage of {A}×100 is preferably 1% or more and 10% or less, preferably 1.5% or more and 9.0% or less, preferably 2.0% or more and 8.0% or less, preferably 5.3% or more and 10.0% or less, and preferably 6.0% or more and 10.0% or less. When the first unit layer has a composition that varies in the thickness direction, the above-mentioned {A} Si / (A Si +A M )}×100 refers to the average value in the first unit layer.

[0184] The number of silicon atoms A in the second unit layer Si Relative to the number of atoms A of the metallic element M And the number of atoms A of silicon Si The total percentage {A} Si / (A Si +A M The lower limit of )}×100 is preferably 0.1% or more, preferably 0.2% or more, and preferably 0.5% or more. The number of silicon atoms A in the second unit layer Si Relative to the number of atoms A of the metallic elementM And the number of atoms A of silicon Si The total percentage {A} Si / (A Si +A M The upper limit of )}×100 is preferably 2.0% or less, preferably 1.5% or less, preferably 1.2% or less, and preferably 1.0% or less. From the viewpoint of improving adhesion, the number of silicon atoms A in the second unit layer Si Relative to the number of atoms A of the metallic element M And the number of atoms A of silicon Si The total percentage {A} Si / (A Si +A M The content of {A}×100 is preferably 0.1% or more and 2.0% or less, preferably 0.5% or more and 2.0% or less, preferably 0.2% or more and 1.5% or less, preferably 0.5% or more and 1.5% or less, and more preferably 0.5% or more and 1.0% or less. When the second unit layer has a configuration in which the composition varies in the thickness direction, the above-mentioned {A} Si / (A Si +A M )}×100 refers to the average value in the second unit layer.

[0185] From the perspective of improving hardness, {A} in the first unit layer Si / (A Si +A M )}×100 and {A in the second unit layer Si / (A Si +A M The difference between )}×100 is preferably 0.5% or more and 10% or less, preferably 1% or more and 9% or less, preferably 2% or more and 8% or less, and preferably 4% or more and 8% or less.

[0186] The first unit layer and the second unit layer may each have a configuration consisting of a single component or a configuration with varying compositions in their thickness direction. In this case, {A} in the first unit layer described above... Si / (A Si +A M )}×100 refers to {A} in the first unit layer of the region where line analysis was performed. Si / (A Si +A M The average of )}×100. Additionally, the {A} in the second unit layer mentioned above... Si / (A Si +A M )}×100 refers to {A} in the second unit layer of the region where line analysis was performed. Si / (ASi +A M The average of )}×100.

[0187] It was confirmed that as long as the measurement is performed on the same sample, even if the hard particles determined in (A2) are changed and the measurement is performed multiple times, the measurement results are almost without deviation, and the results will not change arbitrarily even if the measurement site is set arbitrarily.

[0188] (Average composition of multilayer structures)

[0189] The average composition of the multilayer structure is obtained by calculating the average composition of the region to which the line analysis was performed based on the results of the line analysis described above (A5).

[0190] From the perspective of improving heat resistance, the region {A} was analyzed using line analysis. Si / (A Si +A M The average percentage of 100 is preferably 1% or more and 8% or less, more preferably 1.5% or more and 7.5% or less, and even more preferably 2% or more and 5% or less.

[0191] In this specification, the above-mentioned {A} Si / (A Si +A M The average of )}×100 refers to the average of the values ​​obtained by performing line analysis on three adjacent hard particles.

[0192] (Crystal orientation of the first and second unit layers)

[0193] The first and second unit layers preferably have the same crystal orientation. This suppresses interfacial energy. Examples of such crystal orientations include {311}, {211}, {110}, {100}, and {111}. In the crystallographic descriptions of this specification, {} denote aggregate planes.

[0194] The fact that the first and second unit layers have the same crystal orientation is confirmed by the following steps. Using the same method as described in (A1) to (A4) above, the following results are obtained: Figure 6 The electron diffraction pattern shown. In the case that this electron diffraction pattern is from a single crystal, it is determined that the first unit layer and the second unit layer have the same crystal orientation.

[0195] (Period width of multi-layered structures)

[0196] From the viewpoint of maintaining interlayer strain and improving defect resistance, the average period width of the multilayer structure in this embodiment is preferably 2 nm or more and 20 nm or less, preferably 4.1 nm or more and 17.7 nm or less, preferably 3 nm or more and 15 nm or less, and preferably 5 nm or more and 10 nm or less. Here, the period width of the multilayer structure refers to the distance from one first unit layer to another first unit layer that is adjacent to a second unit layer that is adjacent to that first unit layer. In addition, this distance is set as the distance between the midpoints of the thickness directions of the layers connecting the first unit layer and the other first unit layer. The average period width of the multilayer structure refers to the average of the period widths of all multilayer structures measured within the measurement area set in (A3) above.

[0197] In this specification, the method for determining the period width of silicon concentration is as follows. The measurement region is set using the same method as described in (A1) to (A3) above. A Fourier transform is performed on this measurement region to obtain a Fourier transform image. Figure 8 Indicates to Figure 5 The Fourier transform image obtained by performing a Fourier transform on region A shown is shown. In this Fourier transform image, the periodicity within the measurement region is represented by a light spot. The period width is calculated by taking the reciprocal of the distance between the light spot and the center of the image representing the maximum intensity in the Fourier transform image.

[0198] It was confirmed that as long as the measurement is performed on the same sample, even if the measurement site is changed multiple times, the measurement results will have almost no deviation, and even if the measurement site is set arbitrarily, the results will not change arbitrarily.

[0199] The number of stacked first and second unit layers constituting the multilayer structure (total number of stacked layers) is not particularly limited, but is preferably 10 or more and 1000 or less. If the number of stacked layers is 10 or more, grain coarsening in each unit layer can be suppressed, and the hardness of the hard particles can be maintained. On the other hand, if the number of stacked layers is 1000 or less, the thickness of each unit layer can be sufficiently ensured, and mixing between unit layers can be suppressed.

[0200] <Basal layer>

[0201] Preferably, the coating includes a base layer disposed between the substrate and the rigid particle layer, the base layer being composed of a third compound comprising the following elements:

[0202] Choose one or more elements from the group consisting of Group 4, Group 5, Group 6 elements, and aluminum in the periodic table; and

[0203] Choose one or more elements from the group consisting of carbon, nitrogen, boron, and oxygen.

[0204] As a result, the adhesion between the coating and the substrate is improved, and the wear resistance is also improved.

[0205] By placing a TiN layer, TiC layer, TiCN layer, or TiBN layer directly above the substrate as a base layer, the adhesion between the substrate and the coating can be improved. Using an Al2O3 layer as a base layer can improve the oxidation resistance of the coating. The average thickness of the base layer is preferably 0.1 μm or more and 20 μm or less. Therefore, the coating exhibits excellent wear resistance and damage resistance.

[0206] <Surface Layer>

[0207] Preferably, the coating has a surface layer disposed on its outermost surface, the surface layer being composed of a fourth compound comprising the following elements:

[0208] Choose one or more elements from the group consisting of Group 4, Group 5, Group 6 elements, and aluminum in the periodic table; and

[0209] One or more elements are selected from the group consisting of carbon, nitrogen, boron, and oxygen. This improves the coating's resistance to heat cracking and its abrasion resistance.

[0210] The surface layer is the layer disposed on the outermost side of the coating. However, there are cases where no surface layer is formed at the blade edge. When no other layers are formed on the hard particle layer, the surface layer is disposed directly above the hard particle layer.

[0211] As a surface layer, TiN or Al2O3 layers can be used. TiN layers have a clear, golden color, making them easy to identify (and thus, easily identifiable) the corners of the cutting tool after use. Using an Al2O3 layer as the surface layer improves the coating's oxidation resistance.

[0212] The average thickness of the surface layer is preferably 0.05 μm or more and 1 μm or less. This improves the adhesion between the surface layer and adjacent layers.

[0213] <Intermediate Layer>

[0214] The intermediate layer is disposed between the substrate layer and the hard particle layer. When the substrate layer is a TiN layer, the intermediate layer is preferably a TiCN layer. Since the TiCN layer has excellent wear resistance, appropriate wear resistance can be imparted through coating. The average thickness of the intermediate layer is preferably 1 μm or more and 20 μm or less.

[0215] [Implementation Method 2: Method for Manufacturing a Cutting Tool]

[0216] use Figure 10 The manufacturing method of the cutting tool according to this embodiment will be described. Figure 10 This is a schematic cross-sectional view of an example of a CVD apparatus used in the manufacture of the cutting tool in this embodiment.

[0217] The manufacturing method of the cutting tool in this embodiment is the manufacturing method of the cutting tool described in Embodiment 1, wherein,

[0218] The manufacturing method of this cutting tool includes:

[0219] The first step involves preparing the substrate; and

[0220] In the second step, a coating is formed on the substrate to obtain the cutting tool.

[0221] The second step includes a second step, step 2a, which forms a hard particle layer composed of hard particles by CVD.

[0222] The second step includes a second step (2a-1) in which a first raw material gas, a second raw material gas, and a third raw material gas are sprayed toward the surface of the substrate.

[0223] The first feedstock gas contains one or more elements selected from the group consisting of Group 4, Group 5, and Group 6 elements of the periodic table.

[0224] The second raw material gas is SiCl4.

[0225] The third feed gas contains one or more elements selected from the group consisting of carbon, nitrogen, boron, and oxygen.

[0226] The first raw material gas is ejected from a plurality of first injection holes provided in the nozzle.

[0227] The second raw material gas is ejected from a plurality of second injection holes provided in the nozzle.

[0228] The third raw material gas is ejected from a plurality of third injection holes provided in the nozzle.

[0229] In this 2a-1 step, the nozzle rotates.

[0230] The plurality of second injection holes includes injection hole 2-1 and injection hole 2-2.

[0231] The diameter r1 of the second-1 injection hole is different from the diameter r2 of the second-2 injection hole.

[0232] (Step 1)

[0233] In the first step, a substrate is prepared. Details of the substrate are described in Embodiment 1, and therefore will not be repeated.

[0234] (Step 2)

[0235] Next, in the second step, a coating is formed on the aforementioned substrate to obtain the cutting tool. The coating is formed, for example, using... Figure 10 The CVD apparatus shown is used for this process. Within the CVD apparatus 50, multiple substrate mounting fixtures 52 for holding substrates 10 are installed, and these fixtures are covered by a reaction vessel 53 made of heat-resistant alloy steel. Furthermore, a temperature control device 54 is arranged around the reaction vessel 53, allowing for temperature control within the reaction vessel 53.

[0236] The CVD apparatus 50 is equipped with a nozzle 56 having three inlet ports 55 and 57 (another inlet port is not shown). The nozzle 56 is configured to penetrate the area of ​​the substrate setting fixture 52. A plurality of injection holes (first injection hole 61, second injection hole 62, and third injection hole (not shown)) are formed in the portion of the nozzle 56 near the substrate setting fixture 52.

[0237] exist Figure 10 In this process, the gases introduced into the nozzle 56 from inlet 55, inlet 57, and another inlet (not shown) do not mix within the nozzle 56, but are instead introduced into the reaction vessel 53 through different injection holes. The nozzle 56 is capable of rotating around its axis. Furthermore, the CVD apparatus 50 is equipped with an exhaust pipe 59, from which exhaust gases are discharged to the outside through exhaust port 60. Additionally, the fixtures and other components within the reaction vessel 53 are typically made of graphite.

[0238] In cases where the coating comprises a base layer, an intermediate layer, and / or a surface layer, these layers can be formed using methods known in the art.

[0239] (Process 2a)

[0240] The second step includes a second step, a second step, to form a hard particle layer composed of hard particles by CVD, and the second step includes a second step, a second step, a third step, to spray a first raw material gas, a second raw material gas, and a third raw material gas toward the surface of the substrate.

[0241] The first raw material gas contains one or more elements selected from the group consisting of elements in Groups 4, 5, and 6 of the periodic table. For example, the first raw material gas is a chloride gas of an element in Group 4, 5, or 6 of the periodic table. More specifically, examples include TiCl4, ZrCl4, VCl4, CrCl3, and mixtures containing two or more of these. The second raw material gas is SiCl4. The third raw material gas is, for example, CH3CN, CH4, N2, NH3, BCl3, H2O, and mixtures containing two or more of these.

[0242] The first source gas is ejected from a plurality of first ejection holes provided in the nozzle, the second source gas is ejected from a plurality of second ejection holes provided in the nozzle, and the third source gas is ejected from a plurality of third ejection holes provided in the nozzle. Specifically, the first source gas is introduced into the nozzle 56 from the inlet 55 of the nozzle and ejected from the plurality of first ejection holes 61. The second source gas is introduced into the nozzle 56 from the inlet 57 of the nozzle and ejected from the plurality of second ejection holes 62. The third source gas is introduced into the nozzle (not shown) from the inlet of the nozzle and ejected from the plurality of third ejection holes (not shown).

[0243] In the 2a-1 process, the nozzle rotates. The plurality of second ejection holes include a 2-1 ejection hole and a 2-2 ejection hole. The diameter r1 of the 2-1 ejection hole is different from the diameter r2 of the 2-2 ejection hole. Thereby, the hard particles can include a multilayer structure including a first unit layer and a second unit layer. The percentage of the number of silicon atoms in the first unit layer relative to the total number of metal element and silicon atoms is different from the percentage of the number of silicon atoms in the second unit layer relative to the total number of metal element and silicon atoms. Hereinafter, for easy understanding, it is described with r1 < r2.

[0244] The diameter r1 of the 2-1 ejection hole is preferably 0.5 mm or more and 3 mm or less, more preferably 1 mm or more and 2.5 mm or less, and still more preferably 1.5 mm or more and 2 mm or less. The diameter r2 of the 2-2 ejection hole is preferably 1 mm or more and 4 mm or less, more preferably 1.5 mm or more and 3.5 mm or less, and still more preferably 2 mm or more and 3 mm or less.

[0245] The lower limit of the ratio r1 / r2 of the diameter r1 of the 2-1 ejection hole to the diameter r2 of the 2-2 ejection hole is preferably 0.125 or more, more preferably 0.2 or more, and still more preferably 0.5 or more. The upper limit of r1 / r2 is preferably less than 1, preferably 0.8 or less, and preferably 0.6 or less. r1 / r2 is preferably 0.125 or more and less than 1, preferably 0.2 or more and 0.8 or less, and preferably 0.5 or more and 0.6 or less.

[0246] In this process, the substrate temperature inside the reaction vessel is preferably in the range of 700–900°C, and the pressure inside the reaction vessel is preferably 0.1–13 kPa. Additionally, H2, N2, Ar, etc., can be used as the carrier gas. The composition of the first and second unit layers can be controlled by the mixing ratio of the raw material gases and the ratio r1 / r2 of the diameter of the 2-1 injection hole to the diameter of the 2-2 injection hole. The thickness of the hard particle layer can be controlled by adjusting the flow rate of the raw material gas and the film formation time. The thickness of the first and second unit layers, their stacking period, and the number of stacks can be controlled by adjusting the nozzle rotation speed and the film formation time.

[0247] During the formation of the hard particle layer, the total gas flow rate of the reaction gas can be set to, for example, 70–90 L / min. Here, “total gas flow rate” refers to the total volumetric flow rate introduced into the CVD furnace per unit time, taking the gas under standard conditions (0°C, 1 atmosphere) as an ideal gas.

[0248] (Other processes)

[0249] Next, the substrate 10 with the coating is cooled. The cooling rate is, for example, no more than 5°C / min, and the cooling rate slows down as the temperature of the substrate 10 decreases.

[0250] In addition to the above-mentioned processes, heat treatment processes such as annealing, surface grinding, and shot peening can also be performed.

[0251] The cutting tool of Embodiment 1 can be obtained by the manufacturing method described above.

[0252] Example

[0253] The present embodiment will be further described in detail through examples. However, the present embodiment is not limited to these examples.

[0254] <Substrate Preparation (Step 1)>

[0255] Prepare substrate A as shown in Table 1 below. Specifically, first, uniformly mix the raw material powders consisting of the composition (mass %) shown in Table 1 to obtain a mixed powder. "Balance" in Table 1 indicates the remaining portion of WC in the composition (mass %). Next, press the mixed powder into the shape of SEMT13T3AGSR-G (an indexable cutting insert manufactured by Sumitomo Electric Industries, Ltd.), and sinter it at 1300–1500°C for 1–2 hours to obtain cemented carbide substrate A. The shape of substrate A is SEMT13T3AGSR-G.

[0256] Table 1

[0257]

[0258] <Coating Formation (Step 2)>

[0259] For the substrate A obtained above, a coating is formed on its surface. Specifically, using Figure 10 The CVD apparatus shown depicts a substrate placed in a substrate fixture, where a thermal CVD method is performed to form a coating on the substrate. The composition of the coatings for each sample is shown in Table 2. A column marked with a "-" in Table 2 indicates the absence of that layer.

[0260] Table 2

[0261]

[0262] The substrate layer (TiN layer), intermediate layer (TiCN layer), and surface layer (Al2O3 layer) shown in Table 2 are layers formed using conventional CVD methods, and their film formation conditions are shown in Table 3. For example, the film formation conditions for the TiN layer (substrate layer) as the substrate layer are shown in the "TiN (substrate layer)" row of Table 3. The description of the TiN layer (substrate layer) in Table 3 refers to the following: a substrate is placed in the reaction vessel of a CVD apparatus (pressure inside the reaction vessel is 6.7 kPa, substrate temperature is 915°C), and a mixed gas consisting of 2.0 vol% TiCl4 gas, 39.7 vol% N2 gas, and the balance (58.3 vol%) H2 gas is sprayed into the reaction vessel at a flow rate of 63.8 L / min, thereby forming the TiN layer. Furthermore, the thickness of each layer formed according to each film formation condition is controlled by the spraying time of each reaction gas.

[0263] Table 3

[0264]

[0265] The film formation conditions A-G, X, and Y in the hard particle layer column of Table 2 correspond to the film formation conditions A-G in Table 4 and the film formation conditions X and Y in Table 5. For example, the hard particle layer of sample 1 indicates that the layer was formed under film formation condition A in Table 4, and the value in parentheses means that the thickness of the hard particle layer is 4.5 μm.

[0266] Table 4

[0267]

[0268] (Film-forming conditions A to G)

[0269] Under film-forming conditions A to G, use Figure 10The CVD apparatus shown forms a hard particulate layer. The nozzle of the CVD apparatus is provided with a first injection hole, a second injection hole (including a second-1 injection hole and a second-2 injection hole), and a third injection hole. The diameter of the second-1 injection hole in the nozzle of the CVD apparatus used under various film formation conditions is... and the diameter of the 2-2 injection hole The diameter of the injection hole is shown in Table 4. The "r1 / r2" column. For example, under film formation condition A, the diameter of the 2-1 injection orifice. The diameter of the second-to-second injection hole is 1.5 mm. The nozzle is 2.5mm in diameter. It rotates during the film formation process.

[0270] In film formation conditions A to G, firstly, the pressure inside the reaction vessel of the CVD apparatus is set to the pressure listed in the "Pressure (kPa)" column of Table 4, and the substrate temperature is set to the temperature listed in the "Temperature (°C)" column of Table 4. For example, in film formation condition A, the pressure inside the reaction vessel of the CVD apparatus is set to 9.0 kPa, and the substrate temperature is set to 800°C.

[0271] Next, a reaction gas containing the components listed in the "Reaction Gas Composition (volume %)" column of Table 4 is introduced into the reaction vessel to form a hard particulate layer on the substrate. The "Balance" in Table 4 indicates the remaining portion of the reaction gas composition (volume %) containing H2 gas. In the reaction gas, TiCl4, ZrCl4, VCl4, and CrCl3 are the first raw material gases, SiCl4 is the second raw material gas, and CH3CN and BCl3 are the third raw material gases. H2 is mixed with the third raw material gas to adjust the total gas flow rate.

[0272] Under film-forming conditions A through G, the total gas flow rate of the reaction gases is 80 L / min. "Total gas flow rate" represents the total volumetric flow rate introduced into the CVD furnace per unit time, assuming the gas is under standard conditions (0°C, 1 atmosphere) as an ideal gas. For example, the reaction gases used in film-forming condition A consist of 1 vol% SiCl4 gas, 1 vol% TiCl4 gas, 0.5 vol% CH3CH gas, and H2 gas (balance, 97.5 vol%).

[0273] The nozzle rotation speed during the film formation process is shown in the "Rotation Speed ​​(rpm)" column of Table 4. For example, under film formation condition A, the nozzle rotation speed is 2.0 rpm.

[0274] Then, the substrate is cooled.

[0275] (Film-forming condition X)

[0276] Under film formation conditions X, a hard granular layer is formed using a conventional CVD apparatus. The diameter of the nozzle orifice of the CVD apparatus... All are identical, 10mm. The nozzle does not rotate during film formation.

[0277] Under film formation conditions X, firstly, the pressure inside the reaction vessel of the CVD apparatus is set to 6 kPa, and the substrate temperature is set to 800°C.

[0278] Next, a reaction gas containing the components listed in the "Reaction Gas Composition (volume %)" column of Table 5 (SiCl4: 0.84 vol%, TiCl4: 0.17 vol%, CH3CN: 0.32 vol%, H2: balance) was introduced into the reaction vessel to form a TiSiCN layer (hard particle layer) on the substrate. The total gas flow rate of the reaction gas was 80 L / min. Afterward, the substrate was cooled.

[0279] (Film formation condition Y)

[0280] Under film-forming condition Y, a hard granular layer is formed using the conventional PVD method. The specific conditions for film-forming condition Y are shown in the "Film-forming Condition Y" column of Table 5.

[0281] Based on the above, cutting tools for specimens 1 to 16 (equivalent to examples) and specimens 1-1 to 1-4 (equivalent to comparative examples) were obtained.

[0282] Table 5

[0283]

[0284] Characteristics of hard granular layers

[0285] (Structure of the hard granular layer)

[0286] Bright-field scanning electron microscopy (BF-SEM) was used to observe the hard particle layer coated under film deposition conditions A to G. The results showed that the hard particle layer consisted of multiple hard particles, and a multilayer structure was confirmed within these hard particles. It was confirmed that the multilayer structure of the hard particle layer obtained under film deposition conditions A to G was formed by alternating layers of layers with a high percentage of silicon atoms relative to the total number of metal elements and silicon atoms (first unit layer) and layers with a low percentage of silicon atoms relative to the total number of metal elements and silicon atoms (second unit layer).

[0287] It was confirmed that the first and second unit layers in the hard particle layers obtained by film formation conditions A to G have the same crystal orientation.

[0288] The hard particle (TiCN) layer obtained under film-forming condition X was observed using bright field scanning electron microscopy (BF-SEM). The results showed that the tissue was homogeneous and no periodic changes were identified.

[0289] The hard particle layer obtained under film formation condition Y was observed using bright field scanning electron microscopy (BF-SEM), and the results confirmed the nanocomposite structure.

[0290] (Average composition of multi-layer structure, {A} in the first unit layer) Si / (A Si +A M )}×100(%), {A in the second unit layer Si / (A Si +A M )}×100(%))

[0291] For hard particle layers obtained under various film-forming conditions, the percentage of the average composition of the multilayer structure, the percentage of silicon atoms in the first unit layer relative to the total number of metal elements and silicon atoms ({A) Si / (A Si +A M )}×100(%)), and the percentage of the number of silicon atoms in the second unit layer relative to the total number of metal elements and silicon atoms ({A) Si / (A Si +A M The results were measured at 100% (%). The specific measurement method is as described in Embodiment 1, therefore it will not be repeated. The results are shown in Table 6 under "Average Composition" and "First Unit Layer {A}". Si / (A Si +A M ")}×100(%)" and "Second unit layer {A Si / (A Si +A M The column is labeled ")}×100(%)". Additionally, a "-" indicates that no measurement was performed.

[0292] (Period width)

[0293] In the hard particle layers obtained under various film-forming conditions, the average value of the period width of the multilayer structure was measured. The specific measurement method is as described in Embodiment 1, and therefore will not be repeated. The results are shown in the "Average Period Width (nm)" column of Table 6. In addition, the "-" mark indicates that no measurement was performed.

[0294] Table 6

[0295]

[0296] <Cutting Experiment 1>

[0297] Using the cutting tools of specimens 1 to 10, 1-1, and 1-3, cutting was performed under the following cutting conditions, and the cutting distance until the tool tip became chipped was measured. The following cutting conditions are equivalent to milling (dry machining) of high-hardness, heat-resistant stainless steel. A longer cutting distance indicates a longer tool life. The results are shown in Table 7.

[0298] <Cutting Conditions>

[0299] Workpiece to be cut: SUS630 / H900 block material (dimensions: 300mm×150mm×50mm)

[0300] Cutting tool: WGX13100RS (manufactured by Sumitomo Electric Industries, Ltd.)

[0301] Blade: SEMT13T3AGSR-G

[0302] Cutting speed Vc: 300m / min

[0303] Feed per blade Fz: 0.1mm / t

[0304] Cutting depth Ap: 1.0mm

[0305] Cutting width Ae: 75mm

[0306] Cutting fluid: None (dry type)

[0307] Table 7

[0308]

[0309] (Evaluation 1)

[0310] It was confirmed that, compared with samples 1-1 and 1-3 (comparative examples), samples 1-10 (examples) exhibited longer cutting distances and longer tool life in the milling (dry machining) of high-hardness heat-resistant stainless steel. This is presumably because the hard particles in samples 1-10 contain a multi-layered structure, thus improving resistance to heat cracking and peeling.

[0311] <Cutting Experiment 2>

[0312] Using the cutting tools of specimens 11–16, 1-2, and 1-4, cutting was performed under the following cutting conditions, and the cutting distance until the tool tip became chipped was measured. The following cutting conditions are equivalent to milling (wet machining) of high-hardness, heat-resistant stainless steel. A longer cutting distance indicates better heat resistance and longer tool life. The results are shown in Table 8.

[0313] <Cutting Conditions>

[0314] Workpiece to be machined: SUS640 / H900 block material (dimensions: 300mm×150mm×50mm)

[0315] Cutting tool: WGX13100RS (manufactured by Sumitomo Electric Industries, Ltd.)

[0316] Blade: SEMT13T3AGSR-G

[0317] Cutting speed Vc: 150m / min

[0318] Feed per blade fz: 0.3mm / t

[0319] Cutting depth (ap): 1.0mm

[0320] Cutting width ae: 75mm

[0321] Cutting fluid: wet

[0322] Table 8

[0323]

[0324] (Evaluation 2)

[0325] It was confirmed that, compared with samples 1-2 and 1-4 (comparative examples), samples 11-16 (examples) exhibited longer cutting distances and longer tool life in milling (wet machining) of high-hardness heat-resistant stainless steel. This is presumably because the hard particles in samples 11-16 contain a multi-layered structure, thus improving resistance to heat cracking and peeling.

[0326] The embodiments and examples of this disclosure have been described above, but it is also intended from the outset that the above-described embodiments and examples may be appropriately combined or modified.

[0327] The embodiments and examples disclosed herein should be considered exemplary in all respects, and not restrictive. The scope of the invention is defined not by the foregoing embodiments and examples, but by the claims, and is intended to include all modifications equivalent to and within the scope of the claims.

[0328] Explanation of reference numerals in the attached figures

[0329] 1, 21, 31, 41: Cutting tools; 10: Substrate; 11: Hard particle layer; 12: Base layer; 13: Surface layer; 14: Intermediate layer; 15, 25, 35, 45: Coating; 50: CVD device; 52: Substrate mounting fixture; 53: Reaction vessel; 54: Temperature control device; 55, 57: Inlet; 56: Nozzle; 59: Exhaust pipe; 60: Exhaust port; 61: First injection hole; 62: Second injection hole.

Claims

1. A cutting tool comprising a substrate and a coating film provided on the substrate, wherein the coating film has a hard particle layer composed of hard particles, the hard particle layer has a multilayer structure in which a first unit layer and a second unit layer are alternately stacked, the first unit layer is composed of a first compound having a cubic crystal structure, the second unit layer is composed of a second compound having a cubic crystal structure, the first compound and the second compound are each composed of: one or more metal elements selected from the group consisting of a Group 4 element, a Group 5 element, and a Group 6 element of the periodic table; silicon; and one or more elements selected from the group consisting of boron and oxygen, the first unit layer and the second unit layer have the same crystal orientation.

3. The cutting tool according to claim 1 or 2, wherein the thickness of the hard particle layer is 3 μm or more and 15 μm or less, and the thickness of the coating film is 3 μm or more and 30 μm or less. The atomic number A of silicon in the first unit layer Si The atomic number A of metal element M The atomic number A of silicon Si The percentage of the sum of the atomic number A of metal element and the atomic number A of silicon Si {A Si +A M} × 100 is 6.0% or more and 10% or less, The atomic number A of silicon in the second unit layer Si The atomic number A of metal elements M The atomic number A of silicon Si The atomic number A of silicon Si The atomic number A of silicon Si The atomic number A of silicon M is 0.5% or more and 1.0% or less.

2. The cutting tool of claim 1, wherein, 4. The cutting tool according to claim 1 or 2, wherein the thickness of the hard particle layer is 5 μm or more and 10 μm or less, and the thickness of the coating film is 10 μm or more and 20 μm or less.

5. The cutting tool according to claim 1 or 2, wherein the coating film has a base layer provided between the substrate and the hard particle layer, the base layer is composed of a third compound, the third compound is composed of: one or more elements selected from the group consisting of a Group 4 element, a Group 5 element, a Group 6 element, and aluminum; and one or more elements selected from the group consisting of carbon, nitrogen, boron, and oxygen.

6. The cutting tool according to claim 1 or 2, wherein the coating film has a base layer provided directly above the substrate, the base layer is composed of at least one selected from the group consisting of a TiN layer, a TiC layer, a TiCN layer, a TiBN layer, and an AI2O3 layer.

7. The cutting tool according to claim 1 or 2, wherein the coating film has a surface layer provided on the outermost surface thereof, the surface layer is composed of a fourth compound, the fourth compound is composed of: one or more elements selected from the group consisting of a Group 4 element, a Group 5 element, a Group 6 element, and aluminum; and one or more elements selected from the group consisting of carbon, nitrogen, boron, and oxygen, the surface layer is a TiN layer. the coating film has an intermediate layer provided between the base layer and the hard particle layer. the average of the period width of the multilayer structure is 2 nm or more and 20 nm or less.

11. A method for manufacturing a cutting tool according to any one of claims 1 to 10, wherein the method for manufacturing a cutting tool comprises: a first step in which a substrate is prepared; and a second step in which a coating film is formed on the substrate to obtain a cutting tool, the second step includes a second sub-step of forming a hard particle layer composed of hard particles by a CVD method. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 8. The cutting tool of claim 7, wherein, ​ 9. The cutting tool of claim 5, wherein, ​ 10. The cutting tool of claim 1 or 2, wherein, ​ ​ ​ ​ ​ ​ The second 2a-1 process includes ejecting a first raw material gas, a second raw material gas, and a third raw material gas toward a surface of the substrate, The first raw material gas includes one or more elements selected from the group consisting of a Group 4 element, a Group 5 element, and a Group 6 element of the periodic table, The second raw material gas is SiCl4, The third raw material gas includes one or more elements selected from the group consisting of boron and oxygen, The first raw material gas is ejected from a plurality of first ejection holes provided in a nozzle, The second raw material gas is ejected from a plurality of second ejection holes provided in the nozzle, The third raw material gas is ejected from a plurality of third ejection holes provided in the nozzle, In the second 2a-1 process, the nozzle is rotated, The plurality of second ejection holes includes a second-1 ejection hole and a second-2 ejection hole, A diameter r1 of the second-1 ejection hole is different from a diameter r2 of the second-2 ejection hole.

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