Covered tools and cutting tools

Abstract

This coated tool comprises a base body and a coating layer positioned on the base body. The coating layer includes an intermediate layer and a wear-resistant layer positioned on the intermediate layer. The ratio of the average particle diameter of crystal particles constituting the wear-resistant layer relative to the average particle diameter of crystal particles constituting the intermediate layer is 0.7 or lower.

Description

[Technical Field] 【0001】 This disclosure relates to coated tools and cutting tools. [Background technology] 【0002】 As tools used in cutting processes such as turning or milling, coated tools are known in which the surface of a substrate such as cemented carbide, cermet, or ceramics is coated with a coating layer to improve wear resistance and other properties. [Prior art documents] [Patent Documents] 【0003】 [Patent Document 1] International Publication No. 2016 / 017790 [Overview of the project] 【0004】 A coated tool according to one aspect of the present disclosure comprises a substrate and a coating layer located on the substrate. The coating layer includes an intermediate layer and a wear-resistant layer located on the intermediate layer. The ratio of the average grain size of the grains constituting the wear-resistant layer to the average grain size of the grains constituting the intermediate layer is 0.7 or less. [Brief explanation of the drawing] 【0005】 [Figure 1] Figure 1 is a perspective view showing an example of a coating tool according to an embodiment. [Figure 2] Figure 2 is a side cross-sectional view showing an example of a coating tool according to the embodiment. [Figure 3] Figure 3 is a schematic enlarged view of the corner portion of the chip body in the reference example. [Figure 4] Figure 4 is a cross-sectional view showing an example of a coating layer according to the embodiment. [Figure 5] Figure 5 is a front view showing an example of a cutting tool according to the embodiment. [Figure 6] Figure 6 is a graph showing the correlation between cutting time and abrasive wear. [Figure 7] Figure 7 is an image showing the cutting edge condition of the coated tool according to the embodiment after a cutting test. [Figure 8] Figure 8 is an image showing the cutting edge condition of a coated tool in a comparative example after a cutting test. [Modes for carrying out the invention] 【0006】 The following describes in detail, with reference to the drawings, embodiments for carrying out the coating tools and cutting tools according to this disclosure (hereinafter referred to as "embodiments"). These embodiments do not limit the coating tools and cutting tools according to this disclosure. Each embodiment can be combined as appropriate, without contradicting the content. In the following embodiments, the same parts are denoted by the same reference numerals, and redundant descriptions are omitted. 【0007】 As tools used in cutting processes such as turning or milling, coated tools are known in which the surface of a substrate such as cemented carbide, cermet, or ceramics is coated with a coating layer to improve wear resistance and other properties. 【0008】 The conventional technology described above has room for further improvement in terms of enhancing wear resistance. 【0009】 Therefore, there is a need for technology that can overcome the aforementioned problems and improve wear resistance. 【0010】 <Covered Tools> Figure 1 is a perspective view showing an example of a coating tool according to the embodiment. Figure 2 is a side cross-sectional view showing an example of a coating tool according to the embodiment. As shown in Figure 1, the coating tool 1 according to the embodiment has a tip body 2. 【0011】 (Chip body 2) The chip body 2 has a hexahedron shape, for example, in which the top and bottom surfaces (the surfaces intersecting the Z-axis as shown in Figure 1) are parallelograms. 【0012】 One corner portion 201 of the chip body 2 functions as a cutting edge portion. The cutting edge portion has a first surface (for example, the upper surface) and a second surface (for example, the side surface) connected to the first surface. In the embodiment, the first surface functions as a "rake surface" for scooping up chips generated by cutting, and the second surface functions as a "flank surface". A cutting edge is located at at least a part of the ridge line where the first surface and the second surface intersect, and the coated tool 1 cuts the workpiece by applying such a cutting edge to the workpiece. 【0013】 A through hole 5 penetrating the chip body 2 vertically is located at the central portion of the chip body 2. A screw 75 for attaching the coated tool 1 to a holder 70 described later is inserted into the through hole 5 (see FIG. 5). 【0014】 The shape of the coated tool 1 shown in FIG. 1 is merely an example and does not limit the shape of the coated tool according to the present disclosure. The coated tool according to the present disclosure may have, for example, a rod-shaped body having a rotation axis and extending from a first end to a second end, a cutting edge located at the first end of the body, and a groove spirally extending from the cutting edge toward the second end side of the body. 【0015】 As shown in FIG. 2, the chip body 2 has a substrate 10 and a coating layer 20. 【0016】 (Substrate 10) The substrate 10 is formed of, for example, cemented carbide. The cemented carbide contains a hard phase containing at least W (tungsten), specifically WC (tungsten carbide). The cemented carbide may contain a binding phase containing at least one iron group element such as Ni (nickel) or Co (cobalt). As an example, the substrate 10 is made of a WC-based cemented carbide having WC-based hard particles as a hard phase component and Co as a main component of the binding phase. When the substrate 10 is formed of cemented carbide, the substrate 10 has better heat resistance characteristics. 【0017】 The substrate 10 may be formed of a cermet. The cermet may contain, for example, Ti (titanium), specifically TiC (titanium carbide) or TiN (titanium nitride). The cermet may also contain Ni or Co. 【0018】 The substrate 10 may be formed from a cubic boron nitride sintered body containing cubic boron nitride (cBN) particles. The substrate 10 is not limited to cubic boron nitride (cBN) particles, but may also contain particles such as hexagonal boron nitride (hBN), rhombohedral boron nitride (rBN), or wurtzite boron nitride (wBN). 【0019】 The substrate 10 may be formed of ceramics. The ceramics may contain, for example, Al2O3 (aluminum oxide), such as κ-Al2O3 and α-Al2O3. The ceramics may contain other elements in addition to aluminum oxide. For example, in addition to aluminum oxide, the ceramics may contain at least one of magnesium (Mg), calcium (Ca), strontium (Sr), silicon (Si), and a group 3 element of the periodic table. 【0020】 (Coating layer 20) The coating layer 20 covers the substrate 10 for purposes such as improving the wear resistance and heat resistance of the substrate 10. In the example shown in Figure 2, the coating layer 20 covers the entire substrate 10. The arrangement of the coating layer 20 on the substrate 10 is not particularly limited, as long as the coating layer 20 is located on at least the surface of the substrate 10. When the coating layer 20 is located on the first surface (here, the top surface) of the substrate 10, the wear resistance and heat resistance of the first surface are high. When the coating layer 20 is located on the second surface (here, the side surface) of the substrate 10, the wear resistance and heat resistance of the second surface are high. 【0021】 (Regarding damage to the chip itself) Here, we will explain the damage that occurs to the chip body with reference to Figure 3. Figure 3 is a schematic enlarged view of the corner portion 201X of the chip body 2X in a reference example. 【0022】 As shown in Figure 3, the chip body 2X may experience wear such as primary boundary wear D1, secondary boundary wear D2, abrasive wear D3, and crater wear D4. Primary boundary wear D1, secondary boundary wear D2, and abrasive wear D3 are wear that occurs on the flank face, while crater wear D4 is wear that occurs on the rake face. 【0023】 Abrasive wear D3 is a wear phenomenon in which the surface of the chip body 2X is removed by foreign matter interposed between the chip body 2X and the workpiece. Abrasive wear D3 can lead to increased cutting resistance and cutting heat. 【0024】 Primary boundary wear D1 and secondary boundary wear D2 are abrasive wear that occurs at both ends of abrasive wear D3, i.e., at the cutting boundary. The primary boundary is the boundary that contacts the workpiece surface, and the secondary boundary is the boundary that contacts the finished surface of the workpiece. Primary boundary wear D1 may cause burrs to form on the workpiece. Secondary boundary wear D2 may degrade the finished surface of the workpiece or change the dimensions of the workpiece. 【0025】 Crater wear D4 is a type of wear that occurs when the chip body 2X becomes hot and its surface oxidizes, generating a relatively soft oxide. Crater wear D4 may worsen chip evacuation performance. 【0026】 The coating tool 1 according to this embodiment can suitably reduce such damage by devising the configuration of the coating layer 20 that covers the tip body 2. 【0027】 (Composition of the coating layer 20) Here, an example of the configuration of the coating layer 20 according to the embodiment will be described with reference to Figure 4. Figure 4 is a cross-sectional view showing an example of the coating layer 20 according to the embodiment. 【0028】 As shown in Figure 4, the coating layer 20 has an adhesion layer 21, an intermediate layer 22, and an abrasion-resistant layer 23. The adhesion layer 21 is the layer in contact with the substrate 10. The intermediate layer 22 is located on the surface of the adhesion layer 21. The abrasion-resistant layer 23 is located on the surface of the intermediate layer 22. That is, the adhesion layer 21, the intermediate layer 22, and the abrasion-resistant layer 23 are laminated in the order of adhesion layer 21, intermediate layer 22, and abrasion-resistant layer 23 from the surface side of the substrate 10. 【0029】 The adhesion layer 21 is Ti a Al b M c The alloy layer contains the following: M is at least one metal selected from groups 4a, 5a, and 6a of the periodic table and Si. a and b are both atomic ratios of 40 ≤ a ≤ 80 and 0 ≤ b ≤ 55, and a + b + c = 100. As an example, the adhesion layer 21 may be TiAlWNbSi. 【0030】 The adhesion layer 21 does not necessarily need to contain M. In this case, the adhesion layer 21 may be, for example, TiAl. The adhesion layer 21 improves the adhesion of the coating layer 20 to the substrate 10. As a result, the adhesion layer 21 can reduce the occurrence of primary boundary wear D1 and secondary boundary wear D2 on the chip body 2. 【0031】 The intermediate layer 22 is Ti d Al e M f It includes at least one nonmetal selected from carbon, nitrogen, and oxygen. M is at least one metal selected from groups 4a, 5a, and 6a of the periodic table (excluding Cr) and Si. d and e are 0 ≤ d ≤ 55 and 40 ≤ e ≤ 80, and d + e + f = 100. As an example, the intermediate layer 22 may be TiAlWNbSiN. 【0032】 The intermediate layer 22 does not necessarily contain M. In this case, the intermediate layer 22 may be, for example, TiAlN. The intermediate layer 22 has high oxidation resistance. As a result, the intermediate layer 22 can reduce the occurrence of crater wear D4 in the chip body 2. 【0033】 The wear-resistant layer 23 contains Ti g Al h Cr i M j and at least one non-metal selected from carbon, nitrogen, and oxygen. M is at least one metal selected from Groups 4a, 5a, and 6a (excluding Cr) of the periodic table and Si. g to j are all atomic ratios, where 15 ≦ g ≦ 40, 50 ≦ h ≦ 70, and 5 ≦ i ≦ 20, and g + h + i + j = 100. As an example, the wear-resistant layer 23 may be TiAlCrWNbSiN. 【0034】 The wear-resistant layer 23 does not necessarily have to contain M. In this case, the wear-resistant layer 23 may be, for example, TiAlCrN. The wear-resistant layer 23 is a layer that contacts the workpiece when the coated tool 1 cuts the workpiece, and can reduce the occurrence of primary flank wear D1, secondary flank wear D2, and abrasive wear D3 in the tool body 2. 【0035】 The adhesion layer 21, the intermediate layer 22, and the wear-resistant layer 23 may each have Ti and Al as main components. Here, the main component means that the content ratio in atomic% is higher compared to other contained components. When containing Ti and Al as main components, high wear resistance and high defect resistance can be exhibited. Furthermore, when each of the intermediate layer 22 and the wear-resistant layer 23 contains Ti and Al as main components, the thermal expansion difference between the adhesion layer 21, the intermediate layer 22, and the wear-resistant layer 23 can be suppressed to be small. Therefore, cracks are unlikely to occur at the interfaces between the adhesion layer 21 and the intermediate layer 22 and between the intermediate layer 22 and the wear-resistant layer 23, respectively. 【0036】 Based on the above description, it is clear that M in the adhesion layer 21 c、 M in the intermediate layer 22 f and M in the wear-resistant layer 23 j do not need to be limited to specific metal elements, and do not need to be limited to specific contents. 【0037】 The proportion of metal components in the adhesion layer 21, the intermediate layer 22, and the wear-resistant layer 23 can be determined, for example, by analysis using an EDS (energy-dispersive X-ray spectrometer) attached to a STEM (scanning transmission electron microscope). 【0038】 The thickness of the coating layer 20 may be between 2.5 μm and 10 μm. When the thickness of the coating layer 20 is 2.5 μm or more, abrasion resistance (especially resistance to abrasive abrasion D3) can be more easily ensured. When the thickness of the coating layer 20 is 10 μm or less, chipping of the coating layer 20 can be more easily reduced. Therefore, when the thickness of the coating layer 20 is between 2.5 μm and 10 μm, the abrasion resistance and chipping resistance of the coating layer 20 can be improved. 【0039】 The thickness of the adhesion layer 21 may be between 2 nm and 8 nm. When the thickness of the adhesion layer 21 is 2 nm or more, the adhesion of the coating layer 20 to the substrate 10 can be more easily improved. The occurrence of primary boundary wear D1 and secondary boundary wear D2 in the chip body 2 can be more easily reduced. On the other hand, when the thickness of the adhesion layer 21 is 8 nm or less, the plastic deformation of the relatively soft adhesion layer 21 can be reduced, thereby more easily reducing the fracture of the coating layer 20. Therefore, when the thickness of the adhesion layer 21 is between 2 nm and 8 nm, the occurrence of primary boundary wear D1 and secondary boundary wear D2 in the chip body 2 and the fracture of the coating layer 20 can be reduced. 【0040】 The thickness of the intermediate layer 22 may be less than the thickness of the wear-resistant layer 23. For example, the thickness of the intermediate layer 22 may be 0.5 μm or more and 3 μm or less. When the thickness of the intermediate layer 22 is 0.5 μm or more, the occurrence of crater wear D4 on the chip body 2 can be reduced more easily. On the other hand, when the thickness of the intermediate layer 22 is 3 μm or less, the effect of the wear-resistant layer 23 in reducing the occurrence of primary boundary wear D1, secondary boundary wear D2, and abrasive wear D3 on the chip body 2 can be more easily ensured. Therefore, when the thickness of the intermediate layer 22 is 0.5 μm or more and 3 μm or less, damage to the chip body 2 can be reduced more easily. 【0041】 The thickness of the wear-resistant layer 23 may be between 1.5 μm and 7 μm. When the thickness of the wear-resistant layer 23 is 1.5 μm or more, the occurrence of primary boundary wear D1, secondary boundary wear D2, and abrasive wear D3 in the chip body 2 can be more easily reduced. On the other hand, when the thickness of the intermediate layer 22 is 7 μm or less, the effect of the intermediate layer 22 in reducing the occurrence of crater wear D4 in the chip body 2 can be more easily ensured. Therefore, when the thickness of the wear-resistant layer 23 is between 1.5 μm and 7 μm, damage to the chip body 2 can be more easily reduced. 【0042】 Here, an example is shown in which the coating layer 20 consists of an adhesion layer 21, an intermediate layer 22, and an abrasion-resistant layer 23. However, the coating layer 20 does not necessarily have to include an adhesion layer 21. For example, if the adhesion of the coating layer 20 to the substrate 10 is high, and / or if the workpiece is one in which primary boundary wear D1 and secondary boundary wear D2 are unlikely to occur, the coated tool 1 may have a coating layer 20 consisting of an intermediate layer 22 located on the surface of the substrate 10 and an abrasion-resistant layer 23 located on the surface of the intermediate layer 22. 【0043】 In the coating layer 20 according to this embodiment, the ratio of the average grain size W23 of the crystal grains constituting the wear-resistant layer 23 to the average grain size W22 of the crystal grains constituting the intermediate layer 22 is 0.7 or less. The ratio of the average grain size W23 of the crystal grains constituting the wear-resistant layer 23 to the average grain size W22 of the crystal grains constituting the intermediate layer 22 is, for example, 0.5 or less, and may be 0.15 or less. 【0044】 Here, the average grain size W22 of the crystal grains constituting the intermediate layer 22 and the average grain size W23 of the crystal grains constituting the wear-resistant layer 23 can be obtained, for example, as follows. First, a photograph of the cross-section of the coating layer 20, including the intermediate layer 22 and the wear-resistant layer 23, in a direction perpendicular to the surface of the substrate 10 is taken using a STEM (scanning transmission electron microscope) or the like. Next, the maximum and minimum diameters of the crystal grains are obtained for each of a predetermined number of crystal grains constituting the intermediate layer 22 or the wear-resistant layer 23 in the cross-section of the coating layer 20. Here, particles with a maximum diameter of less than 3 nm are excluded from evaluation because it is difficult to evaluate whether or not they are crystal grains. 【0045】 Next, the average of the maximum and minimum diameters of the crystal grains is calculated as the grain size. Then, the average grain size of a predetermined number of crystal grains is calculated as the average grain size. The predetermined number is, for example, a number that allows the average grain size to be determined with approximately three significant figures. 【0046】 If the ratio of the average grain size W22 of the crystal grains constituting the wear-resistant layer 23 to the average grain size W22 of the crystal grains constituting the intermediate layer 22 is 0.7 or less, the average grain size W23 of the crystal grains constituting the wear-resistant layer 23 can be relatively reduced. This reduces the occurrence of cracks in the wear-resistant layer 23. On the other hand, the average grain size W22 of the crystal grains constituting the intermediate layer 22 can be relatively increased. This reduces the propagation of cracks in the intermediate layer 22. 【0047】 If both the average grain size W22 of the crystal grains constituting the intermediate layer 22 and the average grain size W23 of the crystal grains constituting the wear-resistant layer 23 are small, the occurrence of cracks in the wear-resistant layer 23 can be reduced, but it may become difficult to reduce the propagation of cracks in the intermediate layer 22. If both the average grain size W22 of the crystal grains constituting the intermediate layer 22 and the average grain size W23 of the crystal grains constituting the wear-resistant layer 23 are large, the propagation of cracks in the intermediate layer 22 can be reduced, but it may become difficult to reduce the occurrence of cracks in the wear-resistant layer 23. 【0048】 When the ratio of the average grain size W22 of the crystal grains constituting the wear-resistant layer 23 to the average grain size W22 of the crystal grains constituting the intermediate layer 22 is 0.7 or less, both the occurrence of cracks in the wear-resistant layer 23 and the propagation of cracks in the intermediate layer 22 can be reduced. This improves the wear resistance of the coated tool 1. For example, it can improve the wear resistance of the coated tool 1 in heat-resistant alloy machining. As a result, the tool life of the coated tool 1 can be extended. 【0049】 In the coating layer 20 according to this embodiment, the ratio of the average grain size W22 of the crystal grains constituting the wear-resistant layer 23 to the average grain size W22 of the crystal grains constituting the intermediate layer 22 may be 0.05 or more. In this case, the relative increase in the average grain size W22 of the crystal grains constituting the intermediate layer 22 to the average grain size W23 of the crystal grains constituting the wear-resistant layer 23 can be reduced. Therefore, the occurrence of cracks in the intermediate layer 22 can be reduced. As a result, the wear resistance of the coated tool 1 can be further improved. 【0050】 The average grain size W22 of the crystal grains constituting the intermediate layer 22 may be 100 nm or less. In this case, the occurrence of cracks in the intermediate layer 22 can be reduced. This further improves the wear resistance of the coated tool 1. The average grain size W22 of the crystal grains constituting the intermediate layer 22 may be 70 nm or less. In this case, the occurrence of cracks in the intermediate layer 22 can be further reduced. 【0051】 The average grain size W23 of the crystal grains forming the wear-resistant layer 23 may be 70 nm or less. In this case, the occurrence of cracks in the wear-resistant layer 23 can be further reduced. This further improves the wear resistance of the coated tool 1. The average grain size W23 of the crystal grains forming the wear-resistant layer 23 may be 50 nm or less. In this case, the occurrence of cracks in the wear-resistant layer 23 can be further reduced. The average grain size W23 of the crystal grains forming the wear-resistant layer 23 may be 10 nm or less. In this case, the occurrence of cracks in the wear-resistant layer 23 can be further reduced. 【0052】 In this embodiment, the coating layer 20 located on the corner portion 201 of the chip body 2 is designated as the first coating layer 20A, the coating layer located on the first surface (rake face) of the chip body 2 is designated as the second coating layer 20B, and the coating layer located on the second surface (flank face) of the chip body 2 is designated as the third coating layer 20C. The average grain size of the crystal grains in these coating layers 20A, 20B, and 20C is described below. 【0053】 However, the average grain size of the crystal grains in coating layer 20A may be evaluated at a location on the ridge where the first and second surfaces intersect. The average grain size of the crystal grains in coating layer 20B may be evaluated at a location on the first surface 500 μm away from the aforementioned ridge. The average grain size of the crystal grains in coating layer 20C may be evaluated at a location on the second surface 500 μm away from the aforementioned ridge. 【0054】 In each of the coating layers 20A, 20B, and 20C, the ratio of the average grain size W23A, W23B, and W23C of the crystal grains constituting the wear-resistant layer 23 to the average grain size W22A, W22B, and W22C of the crystal grains constituting the intermediate layer 22 may be 0.7 or less. In other words, the values ​​of W23A / W22A, W23B / W22B, and W23C / W22C may each be 0.7 or less. In this case, the wear resistance at the cutting edge, rake face, and flank face is improved. 【0055】 W23A / W22A, W23B / W22B, and W23C / W22C may be the same value or may be different from each other. W23A / W22A may be greater than W23B / W22B and W23C / W22C. For example, the ratio of W23A / W22A to W23B / W22B and W23C / W22C may be 1.05 or greater. 【0056】 The coating layer 20B located on the rake face and the coating layer 20C located on the flank face require high wear resistance. When W23B / W22B and W23C / W22C are relatively small, high wear resistance can be achieved on the rake face and flank face. On the other hand, the coating layer 20A located at the cutting edge requires high fracture resistance in addition to wear resistance. When W23A / W22A are relatively large, high fracture resistance can be ensured at the cutting edge. Therefore, the coated tool 1 as a whole can exhibit high durability. 【0057】 W23B / W22B and W23C / W22C may be the same value or may be different from each other. W23B / W22B may be smaller than W23C / W22C. For example, the ratio of W23B / W22B to W23C / W22C may be 0.95 or less. The rake face, which comes into contact with the chips, is more prone to wear than the flank face. When W23B / W22B in the coating layer 20B located on the rake face, which is prone to wear, is smaller than W23C / W22C, the lifespan of the coated tool 1 is improved. 【0058】 W23C / W22C may be smaller than W23B / W22B. For example, the ratio of W23C / W22C to W23B / W22B may be 0.95 or less. When W23C / W22C in the coating layer 20C located on the relief surface facing the finished surface of the workpiece is smaller than W23B / W22B, the surface accuracy of the finished surface of the workpiece can be improved. 【0059】 The average particle size W23A in coating layer 20A may be larger than the average particle size W23B in coating layer 20B and the average particle size W23C in coating layer 20C. For example, the ratio of W23A to W23B and W23C may be 1.1 or greater. When W23A is relatively large, high fracture resistance at the cutting edge can be ensured. Therefore, the coated tool 1 as a whole can exhibit high durability. 【0060】 For similar reasons, the average particle size W22A in coating layer 20A may be larger than the average particle size W22B in coating layer 20B and the average particle size W22C in coating layer 20C. For example, the ratio of W22A to W22B and W22C may be 1.05 or greater. When W22A is relatively large, high fracture resistance at the cutting edge can be ensured. Therefore, the coated tool 1 as a whole can exhibit high durability. In this case, the ratio of W23A to W23B and W23C may be larger than the ratio of W22A to W22B and W22C. 【0061】 (Method for manufacturing the coating layer 20) Next, an example of a method for manufacturing the coating layer 20 according to this embodiment will be described. The method for manufacturing the coating layer 20 according to this embodiment is not limited to the method described below. 【0062】 The coating layer 20 may be formed, for example, by physical vapor deposition (PVD). For example, if the coating layer 20 is formed using physical vapor deposition while the substrate 10 is held on the inner circumferential surface of the through hole 5, the coating layer 20 can be formed to cover the entire surface of the substrate 10 except for the inner circumferential surface of the through hole 5. 【0063】 Examples of physical vapor deposition methods include ion plating methods such as arc ion plating (AIP) and sputtering. Arc ion plating is a method of depositing a metal or metal nitride film by using an arc discharge in a vacuum atmosphere to evaporate the target metal and combining it with N2 gas or the like as needed. In this case, the bias voltage applied to the substrate 10, which is the object to be coated, may be -30V or less. 【0064】 For example, when producing the coating layer 20 by the arc ion plating method, the coating layer 20 can be produced by the following method. 【0065】 First, an example of a method for manufacturing the adhesion layer 21 will be described. As an example, metal targets of Ti, Al, and M (where M is at least one metal selected from groups 4a, 5a, and 6a of the periodic table and Si), composite alloy targets, or sintered body targets are prepared. 【0066】 Next, the target, which is the metal source, is evaporated and ionized by an arc discharge or glow discharge, and the ionized metal is deposited onto the surface of the substrate 10. The adhesion layer 21 can be formed by the above procedure. 【0067】 The composition of the adhesion layer 21 can be adjusted by independently controlling the voltage or current values ​​during arc discharge or glow discharge applied to each metal target. The composition of the adhesion layer 21 can also be adjusted by controlling the composition of the metal target, the coating time, or the ambient gas pressure. The thickness of the adhesion layer 21 can be adjusted, for example, by controlling the coating time. 【0068】 Next, an example of a method for manufacturing the intermediate layer 22 will be described. As an example, metal targets of Ti, Al, and M (where M is at least one metal selected from groups 4a, 5a, and 6a of the periodic table (excluding Cr) and Si), composite alloy targets, or sintered body targets are prepared. 【0069】 Next, the target, which is the metal source, is evaporated and ionized by an arc discharge or glow discharge. The ionized metal is reacted with nitrogen (N2) gas or the like and deposited onto the surface of the substrate 10. The intermediate layer 22 can be formed by the above procedure. 【0070】 The composition of the intermediate layer 22 can be adjusted by controlling the composition of the metal target. The particle size of the intermediate layer 22 can be adjusted by controlling the current value during arc discharge or glow discharge, or by controlling the ambient gas pressure. The thickness of the intermediate layer 22 can be adjusted, for example, by controlling the coating time. 【0071】 Next, a method for manufacturing the wear-resistant layer 23 will be described. As an example, metal targets of Ti, Al, Cr, and M (where M is at least one metal selected from groups 4a, 5a, and 6a of the periodic table (excluding Cr) and Si), composite alloy targets, or sintered body targets are prepared. 【0072】 Next, the target, which is the metal source, is evaporated and ionized by an arc discharge or glow discharge. The ionized metal is reacted with nitrogen (N2) gas or the like and deposited onto the surface of the substrate 10. The wear-resistant layer 23 can be formed by the above procedure. 【0073】 The composition of the wear-resistant layer 23 can be adjusted by controlling the composition of the metal target. The particle size of the wear-resistant layer 23 can be adjusted by controlling the voltage or current value during arc discharge or glow discharge, or by controlling the ambient gas pressure. The thickness of the wear-resistant layer 23 can be adjusted, for example, by controlling the coating time. 【0074】 <Cutting tools> Next, the configuration of the cutting tool equipped with the coating tool 1 described above will be explained with reference to Figure 5. Figure 5 is a front view showing an example of a cutting tool according to the embodiment. 【0075】 As shown in Figure 5, the cutting tool 100 according to this embodiment includes a coating tool 1 and a holder 70 for fixing the coating tool 1. 【0076】 The holder 70 is a rod-shaped member extending from the first end (upper end in Figure 5) to the second end (lower end in Figure 5). The holder 70 is made of, for example, steel or cast iron. In particular, steel with high toughness may be used among these members. 【0077】 The holder 70 has a pocket 73 at the end on the first end side. The pocket 73 is the part into which the coated tool 1 is mounted, and has a seating surface that intersects with the rotational direction of the workpiece, and a restraining side surface that is inclined with respect to the seating surface. The seating surface is provided with a screw hole into which a screw 75, which will be described later, is screwed. 【0078】 The coating tool 1 is located in the pocket 73 of the holder 70 and is attached to the holder 70 by a screw 75. Specifically, the screw 75 is inserted into the through hole 5 of the coating tool 1, and the tip of the screw 75 is inserted into the screw hole formed in the seating surface of the pocket 73, and the screwed parts are screwed together. In this way, the coating tool 1 is attached to the holder 70 such that the cutting edge portion protrudes outward from the holder 70. 【0079】 In this embodiment, a cutting tool 100 used for so-called turning operations is illustrated. Examples of turning operations include internal diameter machining, external diameter machining, and grooving operations. The cutting tool is not limited to those used for turning operations. For example, a coated tool 1 may be used as a cutting tool for milling operations. Examples of cutting tools used for milling operations include milling cutters such as flat milling cutters, face milling cutters, side milling cutters, and groove milling cutters, and end mills such as single-flute end mills, multi-flute end mills, tapered end mills, and ball end mills. [Examples] 【0080】 The embodiments of this disclosure will be described below in detail. This disclosure is not limited to the embodiments shown below. 【0081】 (Examples) As an example, a coated tool was fabricated by sequentially laminating an adhesion layer, an intermediate layer, and a wear-resistant layer onto a substrate using the arc ion plating method, thereby including a substrate and a coating layer consisting of the adhesion layer, intermediate layer, and wear-resistant layer. WC-based cemented carbide was used as the substrate. Table 1 shows the composition and thickness of the adhesion layer, intermediate layer, and wear-resistant layer formed on the substrate. 【0082】 [Table 1] 【0083】 Next, using a scanning transmission electron microscope, the maximum and minimum diameters of the crystal grains constituting the intermediate layer and the wear-resistant layer were measured for the cutting edge of the coated tool fabricated as an example. Then, the grain sizes of the crystal grains constituting the intermediate layer and the wear-resistant layer were calculated. The ratio of the average grain size of the crystal grains constituting the wear-resistant layer to the average grain size of the crystal grains constituting the intermediate layer was calculated. 【0084】 Table 2 shows the maximum diameter, minimum diameter, and grain size values ​​of the crystal grains constituting the intermediate layer, the maximum diameter, minimum diameter, and grain size values ​​of the crystal grains constituting the wear-resistant layer, and the ratio of the average grain size of the crystal grains constituting the wear-resistant layer to the average grain size of the crystal grains constituting the intermediate layer (average grain size ratio) for the prepared samples No. 1 to No. 11. 【0085】 The grain size, maximum diameter, and minimum diameter of the crystal grains constituting the intermediate layer and wear-resistant layer can be measured as follows. The grain size can be determined by calculating the area of ​​each crystal grain and approximating it with a circle. For example, the grain size can be determined using OIM Analysis from TSL. Using the above software, the crystal grain is approximated as an ellipse, and the major and minor axes of the ellipse are determined. The major and minor axes are taken as the maximum and minimum diameters of the crystal grain, and the average grain size can be determined by averaging the maximum and minimum diameters. 【0086】 Similarly, the maximum and minimum diameters of the crystal grains constituting the intermediate layer and the wear-resistant layer were measured for the cutting edge of a conventional coated tool used as a comparative example. Next, the grain sizes of the crystal grains constituting the intermediate layer and the wear-resistant layer were calculated. The ratio of the average grain size of the crystal grains constituting the wear-resistant layer to the average grain size of the crystal grains constituting the intermediate layer was calculated. The results are shown in Table 2. 【0087】 For the prepared samples No. 1 to No. 11, the maximum diameter, minimum diameter, and grain size of the crystal grains constituting the intermediate layer and the wear-resistant layer were measured, and the ratio of the average grain size of the crystal grains constituting the wear-resistant layer to the average grain size of the crystal grains constituting the intermediate layer was calculated. The crystal grain size was determined under the above conditions. The time it took for the abrasive wear to reach 0.2 mm was measured from images obtained by imaging the abrasive wear of each sample after a cutting test under the following conditions, and the time it took for the abrasive wear to reach 0.2 mm was calculated. 【0088】 [Table 2] 【0089】 As shown in Table 2, it was confirmed that in the coated tool according to the example, the ratio of the average grain size of the crystal grains constituting the wear-resistant layer to the average grain size of the crystal grains constituting the intermediate layer was 0.7 or less for both the cutting edge and the side surface of the coated tool. On the other hand, it was confirmed that the ratio of the average grain size of the crystal grains constituting the wear-resistant layer to the average grain size of the crystal grains constituting the intermediate layer was greater than 0.7 for the cutting edge of the coated tool according to the comparative example. 【0090】 Cutting tests were conducted on the coated tools according to the examples and the coated tools according to the comparative examples. The conditions for the cutting tests are as follows: 【0091】 <Conditions for the cutting test> Workpiece material: Inconel® 718 Cutting speed (Vc): 30m / min Feed rate (f): 0.10mm / rev Cut (ap): 0.5mm Cutting method: Wet Tool used: CNMG120408SG 【0092】 Then, using images showing the cutting edge condition of the coated tool according to the embodiment after the cutting test, the length of abrasive wear in the thickness direction of the coating layer of the coated tool according to the embodiment (hereinafter referred to as "abrasive wear amount") was measured. The cutting times in the cutting test were 7.4 minutes, 14.8 minutes, 19.8 minutes, 24.7 minutes, 29.7 minutes, and 34.6 minutes. 【0093】 Similarly, using images showing the cutting edge condition of the coated tool of the comparative example after the cutting test, the abrasive wear amount in the thickness direction of the coating layer of the coated tool of the comparative example shown in sample No. 8 was measured. The cutting times in the cutting test were 7.4 minutes and 14.8 minutes. 【0094】 Figure 6 is a graph showing the correlation between cutting time and abrasive wear. The horizontal axis of the graph in Figure 6 represents cutting time (minutes). The vertical axis of the graph in Figure 6 represents abrasive wear (mm). In the graph in Figure 6, white circles indicate the measured values ​​for the coated tool according to the example. Black circles indicate the measured values ​​for the coated tool according to the comparative example. 【0095】 As shown in Figure 6, it was confirmed that, at a certain cutting time, the abrasive wear of the coated tool according to the example was less than the abrasive wear of the coated tool according to the comparative example shown in Sample No. 8. In other words, at a certain amount of abrasive wear, it was confirmed that the cutting time of the coated tool according to the example was longer than the cutting time of the coated tool according to the comparative example shown in Sample No. 8. 【0096】 This confirmed that the wear resistance of coated tools can be improved when the ratio of the average grain size of the crystal grains constituting the wear-resistant layer to the average grain size of the crystal grains constituting the intermediate layer is 0.7 or less. In other words, it was confirmed that the tool life of coated tools can be extended. 【0097】 Figures 7 and 8 show the cutting edge condition of the coated tool after cutting for 7.4 minutes under the above cutting conditions. Figure 7 is an image showing the cutting edge condition of the coated tool according to the embodiment after the cutting test. Figure 8 is an image showing the cutting edge condition of the coated tool according to the comparative example after the cutting test. In both Figures 7 and 8, the portion of the coating layer that has been scraped off by abrasive wear D3 and exposed the substrate is indicated by a dotted white circle on the cutting edge of the coated tool. 【0098】 As shown in Figures 7 and 8, it was confirmed that the abrasive wear D3 in the coated tool according to the example was reduced compared to the abrasive wear D3 in the coated tool according to the comparative example shown in sample No. 8. From these results, it was confirmed that the abrasive resistance of the coated tool can be improved when the ratio of the average grain size of the crystal grains constituting the wear-resistant layer to the average grain size of the crystal grains constituting the intermediate layer is 0.7 or less. 【0099】 <Note> Note (1): Substrate and, A coating layer located on the substrate, Equipped with, The coating layer includes an intermediate layer and an abrasion-resistant layer located on the intermediate layer. The ratio of the average grain size of the crystal grains constituting the wear-resistant layer to the average grain size of the crystal grains constituting the intermediate layer is 0.7 or less. Covering tools. Note (2): The average grain size of the crystal grains constituting the intermediate layer is 100 nm or less. The average grain size of the crystal grains constituting the wear-resistant layer is 70 nm or less. The covering tool described in Appendix (1). Note (3): The average grain size of the crystal grains constituting the intermediate layer is 70 nm or less. The average grain size of the crystal grains constituting the wear-resistant layer is 50 nm or less. The covering tools described in Appendix (2). Note (4): The coating layer further includes an adhesion layer that is in contact with the substrate. The covering tool described in any one of the appendices (1) to (3). Note (5): The aforementioned intermediate layer, the abrasion-resistant layer, and the adhesion layer all have Ti and Al as their main components. The covering tools described in Appendix (4). Note (6): The aforementioned substrate is The first surface functions as a scooping surface, The second face functions as an escape surface, The first surface and the second surface intersect at a ridge, The aforementioned coating layer is The first layer is located on the aforementioned ridge, A second layer located above the first surface, It has a third layer located on the second surface, The ratio in the first layer is greater than the ratios in the second and third layers. The covering tool described in any one of the appendices (1) to (5). Note (7): The ratio in the second layer is greater than the ratio in the third layer. The covering tools described in Appendix (6). Note (8): The ratio in the third layer is greater than the ratio in the second layer. The covering tools described in Appendix (6). Note (9): The average grain size of the crystal grains constituting the wear-resistant layer in the first layer is greater than the average grain size of the crystal grains constituting the wear-resistant layer in the second and third layers. The covering tool described in any one of the appendices (6) to (8). Note (10): The average grain size of the crystal grains constituting the intermediate layer in the first layer is greater than the average grain size of the crystal grains constituting the intermediate layers in the second and third layers. A covering tool as described in any one of the appendices (6) to (9). Note (11): A rod-shaped holder having a pocket at the end, The covering tool located within the aforementioned pocket, and one of the covering tools described in any of the appendices (1) to (10) A cutting tool equipped with the following features. 【0100】 Further effects and / or modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of symbols] 【0101】 1. Covering Tools 2. Chip body 5 Through hole 10 Base 20 Covering layer 21. Close contact layer 22 Middle Class 23 Wear-resistant layer 70 Holder 73 pockets 75 screws 100 cutting tools 201 Corner section D1 Primary boundary wear D2 Secondary boundary wear D3 Abrasive Wear D4 Crater wear

Claims

[Claim 1] Substrate and, A coating layer located on the substrate, Equipped with, The coating layer includes an intermediate layer and an abrasion-resistant layer located on the intermediate layer. The ratio of the average grain size of the crystal grains constituting the wear-resistant layer to the average grain size of the crystal grains constituting the intermediate layer is 0.7 or less. The aforementioned substrate is The first surface functions as a scooping surface, The second surface functions as an escape surface, It has a ridge located at the intersection of the first surface and the second surface, The aforementioned coating layer is The first layer located on the aforementioned ridge, A second layer located on the first surface, It has a third layer located on the second surface, The ratio in the first layer is greater than the ratios in the second and third layers. Covering tools. [Claim 2] The average grain size of the crystal grains constituting the intermediate layer is 100 nm or less. The average grain size of the crystal grains constituting the wear-resistant layer is 70 nm or less. The covering tool according to claim 1. [Claim 3] The average grain size of the crystal grains constituting the intermediate layer is 70 nm or less. The average grain size of the crystal grains constituting the wear-resistant layer is 50 nm or less. The covering tool according to claim 2. [Claim 4] The coating layer further includes an adhesion layer that is in contact with the substrate. The covering tool according to claim 1. [Claim 5] The aforementioned intermediate layer, the abrasion-resistant layer, and the adhesion layer all consist mainly of Ti and Al. The covering tool according to claim 4. [Claim 6] The ratio in the second layer is greater than the ratio in the third layer. The covering tool according to claim 1. [Claim 7] The ratio in the third layer is greater than the ratio in the second layer. The covering tool according to claim 1. [Claim 8] The average grain size of the crystal grains constituting the wear-resistant layer in the first layer is greater than the average grain size of the crystal grains constituting the wear-resistant layer in the second and third layers. The covering tool according to claim 1. [Claim 9] The average grain size of the crystal grains constituting the intermediate layer in the first layer is greater than the average grain size of the crystal grains constituting the intermediate layers in the second and third layers. The covering tool according to claim 1. [Claim 10] A rod-shaped holder having a pocket at the end, A covering tool according to any one of claims 1 to 9, located within the aforementioned pocket A cutting tool equipped with the following features.

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