Surface-coated cutting tool

Abstract

This surface-coated cutting tool comprises a base including a WC-based cemented carbide, and a coating layer provided on the base and comprising a lower layer and an upper layer overlying the lower layer, wherein the lower layer has an average thickness of 5-500 nm and has a composition represented by the formula WxTi1-x-y-z-sAyCzNs (A is at least one element selected from the group consisting of Cr, Ta, Nb, and V, the average of x, xavg, satisfies 0.05≤xavg≤0.30, the average of y, yavg, satisfies 0.00≤yavg≤0.05, the average of z, zavg, satisfies 0.00≤zavg≤0.10, the average of s, savg, satisfies 0.05≤savg≤0.30, and xavg≥2×zavg is satisfied) and the upper layer has an average thickness of 0.3-6.0 μm and has a composition represented by the formula AldM11-dN (M1 is at least one element selected from the group consisting of Ti, Cr, Ta, B, Si, Mo, and W, and the average of d, davg, satisfies 0.20≤davg≤0.80).

Description

Coated cutting tool

[0001] The present invention relates to a coated cutting tool (hereinafter sometimes referred to as a coated tool). This application claims priority based on Japanese Patent Application No. 2024-190724, which is a Japanese patent application filed on October 29, 2024. All the descriptions contained in the Japanese patent application are incorporated herein by reference.

[0002] Conventionally, as a coated tool, for example, a coated tool in which a coating layer is formed on a substrate such as a tungsten carbide (hereinafter represented by WC) - based cemented carbide is known. And, by adjusting the composition and layer structure of this coating layer, proposals have been made to obtain a coated tool with further improved cutting performance.

[0003] For example, in Patent Document 1, the coating layer includes a first composite nitride layer containing a compound having a composition represented by (Ti ａ ,

[0004] , ｙ , ｚ , ｘ , １－ａ Al １－ｘ )N (0.10 ≤ x ≤ 0.35), and a second composite nitride layer containing a compound having a composition represented by (Ti ｙ Al ｚ M １－ｙ－ｚ )N (where M represents at least one element selected from the group consisting of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Si, and Y, 0.30 ≤ y ≤ 0.90, 0.10 ≤ z ≤ 0.70, y + z ≤ 1), and the first composite nitride layer and the second composite nitride layer are alternately laminated to have an alternating laminated structure. The first composite nitride layer includes a phase having a lattice constant of 0.400 to 0.430 nm and a phase having a lattice constant of 0.755 to 0.810 nm. The coated tool is described to have wear resistance and chipping resistance.

[0004] Also, for example, in Patent Document 2, (Al ｘ Ti ｙ M ｚ ) ａ N １－ａA coated tool is described having a coating layer having a composition represented by (M is Cr and / or W, 0.6 ≤ x ≤ 0.9, 0.05 ≤ y ≤ 0.4, 0 ≤ z ≤ 0.2, x + y + z = 1 and 0.2 ≤ a ≤ 0.8), wherein the X-ray diffraction pattern shows a single wurtzite-type structure, and the X-ray diffraction peak of the (002) plane of the wurtzite-type structure is the largest peak, and the coated tool is said to have excellent durability.

[0005] International Publication No. 2017 / 175803, International Publication No. 2014 / 142190

[0006] This invention has been made in view of the above circumstances and proposals, and aims to provide a surface-coated cutting tool having a coating layer that exhibits excellent wear resistance and fracture resistance not only when used for cutting steel and cast iron, but also when used for cutting various types of stainless steel.

[0007] The surface-coated cutting tool according to the embodiment of the present invention has the following three embodiments.

[0008] (First Embodiment) A substrate containing a WC-based cemented carbide, and a coating layer provided on the substrate, comprising a lower layer and an upper layer, wherein the lower layer has an average thickness of 5 to 500 nm, Formula: W ｘ Ti １－ｘ－ｙ－ｚ－ｓ A ｙ C ｚ N ｓ (A is at least one element selected from the group Cr, Ta, Nb, V, and the mean value of x is x) ａｖｇ x ≤ 0.05 ａｖｇ ≤ 0.30, mean value of y ａｖｇ is 0.00 ≤ y ａｖｇ ≤ 0.05, mean value of z ａｖｇ is 0.00 ≤ z ａｖｇ ≤ 0.10, mean value of s ａｖｇ is 0.05 ≤ s ａｖｇ ≤ 0.30, x ａｖｇ ≥ 2 × z ａｖｇ The upper layer has a composition represented by (satisfying each of the following conditions), and the upper layer has an average thickness of 0.3 to 6.0 μm, and the formula is Al ｄ M1 １－ｄ N(M1 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W, and the average value of d) ａｖｇis 0.20 ≤ d ａｖｇ Having a composition that satisfies ≤0.80.

[0009] (Second Embodiment) A substrate containing a WC-based cemented carbide, and a coating layer provided on the substrate, comprising a lower layer and an upper layer, wherein the lower layer has an average thickness of 5 to 500 nm, Formula: W ｘ Ti １－ｘ－ｙ－ｚ－ｓ A ｙ C ｚ N ｓ (A is at least one element selected from the group Cr, Ta, Nb, V, and the mean value of x is x) ａｖｇ x ≤ 0.05 ａｖｇ ≤ 0.30, mean value of y ａｖｇ is 0.00 ≤ y ａｖｇ ≤ 0.05, mean value of z ａｖｇ is 0.00 ≤ z ａｖｇ ≤ 0.10, mean value of s ａｖｇ is 0.05 ≤ s ａｖｇ ≤ 0.30, x ａｖｇ ≥ 2 × z ａｖｇ The upper layer has a composition represented by (satisfying the above), the upper layer has an average thickness of 0.3 to 6.0 μm, and consists of a first upper sublayer 1 and a second upper sublayer on the first upper sublayer 1, the first upper sublayer 1 is made of Al ｄ１ M1 １－ｄ１ N(M1 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W, and the average value of d1 is d1 ａｖｇ 0.20 ≤ d1 ａｖｇ The second upper sublayer has a composition represented by the formula: Al (satisfying ≤ 0.80), and the second upper sublayer is represented by the formula: Al ｄ２ M2 １－ｄ２ N(M2 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W, and the average value of d2 is d2) ａｖｇ 0.20 ≤ d2 ａｖｇ The condition ≤ 0.80 is satisfied, where M1 and M2 are different or M1 and M2 are the same and 0.15 ≤ |d1 ａｖｇ -d2 ａｖｇ It has a composition represented by | ≤ 0.60.

[0010] (Third Embodiment) A substrate containing a WC-based cemented carbide, and a coating layer provided on the substrate, comprising a lower layer and an upper layer, wherein the lower layer has an average thickness of 5 to 500 nm, Formula: W ｘ Ti １－ｘ－ｙ－ｚ－ｓ A ｙ C ｚ N ｓ (A is at least one element selected from the group Cr, Ta, Nb, V, and the mean value of x is x) ａｖｇ x ≤ 0.05 ａｖｇ ≤ 0.30, mean value of y ａｖｇ is 0.00 ≤ y ａｖｇ ≤ 0.05, mean value of z ａｖｇ is 0.00 ≤ z ａｖｇ ≤ 0.10, mean value of s ａｖｇ is 0.05 ≤ s ａｖｇ ≤ 0.30, x ａｖｇ ≥ 2 × z ａｖｇ The laminate has a composition represented by (satisfying each of the following conditions), the upper layer has an average thickness of 0.3 to 6.0 μm, and consists of alternating layers of α sublayers and β sublayers with an average thickness of 3 to 20 nm per layer, the α sublayer being made of Al ｐ Ti １－ｐ N(mean value of p) ａｖｇ 0.30 ≤ p ａｖｇ The β sublayer has a composition that satisfies ≤ 0.60, and the β sublayer is made of Al ｑ Ti １－ｑ―ｍ M3 ｍ N(M3 is at least one element selected from the group Cr, Mo, Ta, B, Si, W, and the mean value of q is q ａｖｇ 0.50 ≤ q ａｖｇ ≤ 0.80, average value of m ａｖｇ 0.01 ≤ m ａｖｇ ≤ 0.20, q ａｖｇ -p ａｖｇ The composition must satisfy the condition ≥ 0.01.

[0011] The surface-coated cutting tools according to the three embodiments described above all exhibit excellent wear resistance and fracture resistance when used for cutting not only steel and cast iron, but also various types of stainless steel.

[0012] This is a schematic cross-sectional view of an example of a surface-coated cutting tool according to the first embodiment of the present invention (when the upper layer is a composite nitride of one type of Al and M1). This is a schematic cross-sectional view of an example of a surface-coated cutting tool according to the second embodiment of the present invention (when the upper layer consists of a first upper sublayer and a second upper sublayer). This is a schematic cross-sectional view of an example of a surface-coated cutting tool according to the third embodiment of the present invention (when the upper layer is an alternating laminate of α sublayer and β sublayer).

[0013] The inventors of the present invention have diligently studied coating layers in order to obtain cutting tools that have excellent wear resistance and fracture resistance even when subjected to intermittent cutting of various stainless steels, including austenitic stainless steel, while ensuring performance in cutting processes of steel and cast iron.

[0014] In both continuous and intermittent cutting processes of difficult-to-machine materials such as austenitic stainless steel and other types of stainless steel, welding occurs between the difficult-to-machine material and the coating layer. If the adhesion between the coating layer and the substrate is insufficient, the coating layer will peel off from the substrate, increasing cutting resistance and leading to chipping. To avoid this chipping, a lower layer has traditionally been provided to suppress the peeling of the coating layer from the substrate.

[0015] In CVD deposition, this lower layer can be exemplified by a layer containing Ti nitride and / or Ti carbonitride, and in PVD deposition, it is a layer containing a compound of W and Ti (hereinafter referred to as WTi) in addition to the CVD deposition layer. Under the harsh cutting conditions of recent years, improvements in the performance of this WTi have been eagerly awaited. Therefore, the inventors diligently conducted research to further improve the adhesion of the coating layer to the substrate when this WTi is used as the lower layer. As a result, the following findings were obtained.

[0016] To improve adhesion between the upper and lower layers, it is preferable to ensure that the crystal structures of the compounds constituting the upper and lower layers are aligned at the interface between the upper and lower layers. Therefore, assuming that the upper layer is a compound containing nitrogen, a lower layer containing N in WTi is considered preferable. Furthermore, it was found that when forming a lower layer containing N in WTi, even if the lower layer contains predetermined amounts of C, Cr, Ta, Nb, and V, which are components of the substrate, this does not hinder the resolution of the aforementioned problem.

[0017] Furthermore, when a TiN layer is deposited on a substrate by the CVD method, a WTiCN layer may be formed in a portion of the space between the substrate and the TiN layer. This is because the heat generated during deposition causes the diffusion of C and W from the substrate toward the TiN layer. The composition of this WTiCN layer differs from that of the lower layer in this embodiment because, due to thermal diffusion, more C diffuses than W. On the other hand, conventional WTi films deposited by the PVD method are formed at lower temperatures, so the idea of ​​including N in this WTi film was not considered.

[0018] The inventors have found that even at low film deposition temperatures, WTi targets and Ar+N ２ or N ２ We have found that, depending on the atmosphere, it is possible to incorporate nitrogen into the WTi film by utilizing the energy from ion collisions during the CAE (Cathodic arc evaporation) film deposition process.

[0019] The present invention will be described below by providing a more detailed explanation of the covering tools according to three embodiments of the present invention. In this specification and the claims, when a numerical range is expressed using "L to M", it is synonymous with "greater than or equal to L and less than or equal to M", and the range includes the numerical values ​​of the upper limit (M) and the lower limit (L). Furthermore, when a unit is specified only for the upper limit (M), the upper limit (M) and the lower limit (L) have the same unit.

[0020] The coating tool according to the first embodiment of the present invention is shown in FIG. 1 as a schematic longitudinal sectional view of its coating layer. In this first embodiment, there is a coating layer (2) on the substrate (1), and the coating layer (2) consists of a lower layer (3) and an upper layer (4). Further, the coating tool according to the second embodiment of the present invention is shown in FIG. 2 as a schematic longitudinal sectional view of its coating layer. In this second embodiment, there is a coating layer (2) on the substrate (1), and the coating layer (2) consists of a lower layer (3) and an upper layer (4), and the upper layer (4) consists of a first upper sublayer (5) and a second upper sublayer (6) on the first upper sublayer (5). Furthermore, the coating tool according to the third embodiment of the present invention is shown in FIG. 3 as a schematic longitudinal sectional view of its coating layer. In this third embodiment, there is a coating layer (2) on the substrate (1), and the coating layer (2) consists of a lower layer (3) and an upper layer (4), and the upper layer (4) consists of an α sublayer (7) and a β sublayer (8).

[0021] 1. Coating layer Matters common to the first to third embodiments will be described. The coating layer consists of a lower layer and an upper layer.

[0022] (1) Lower layer The lower layer imparts defect resistance to the coating layer and is the layer directly above the substrate. The average thickness is 5 to 500 nm for the following reasons. If the average thickness is less than 5 nm, the coating layer cannot ensure sufficient adhesion, while if it exceeds 500 nm, the coating layer cannot ensure sufficient defect resistance. A more preferable range for the average thickness of the lower layer is 20 to 300 nm. An even more preferable range is 30 to 150 nm.

[0023] Also, the lower layer has the formula: W ｘ Ti １－ｘ－ｙ－ｚ－ｓ A ｙ C ｚ N ｓ (A is at least one element selected from Cr, Ta, Nb, and V, and the average value x of x ａｖｇ is 0.05 ≤ x ａｖｇ ≤ 0.30, the average value y of y ａｖｇ is 0.00 ≤ y ａｖｇ ≤ 0.05, the average value z of z ａｖｇ is 0.00 ≤ z ａｖｇ ≤ 0.10, the average value s of s ａｖｇ is 0.05 ≤ s ａｖｇ ≤ 0.30, x ａｖｇ ≥ 2 × zａｖｇ It has a composition represented by (satisfying each of the following conditions).

[0024] W, Ti, and N originate from the film-forming components of the lower layer, while C and A (at least one element selected from the group Cr, Ta, Nb, and V) are components contained in the substrate and diffuse from the substrate during film formation of the lower layer, becoming included in the lower layer. Average value of W x ａｖｇ , and the mean value s of N ａｖｇ The reason for setting the range as described above is as follows: x ａｖｇ and s ａｖｇ If both values ​​are smaller than the lower limit, the lower layer cannot ensure sufficient adhesion to the substrate and the upper layer, while if they exceed the upper limit, the coating layer cannot ensure sufficient resistance to chipping.

[0025] It is preferable that element A is not included, but y ａｖｇ If the ratio is 0.05 or less, the lower layer adheres to the substrate. Although C does not need to be included, its inclusion improves the hardness of the lower layer and provides wear resistance. This improvement in strength is due to z ａｖｇ This is achieved by setting the range as described above, and if it exceeds 0.10, the fracture resistance of the lower layer decreases significantly. Also, x ａｖｇ ga z ａｖｇ If it becomes less than twice that amount, the amount of carbon in the lower layer increases, and the toughness of the lower layer decreases. ａｖｇ , y ａｖｇ , z ａｖｇ s ａｖｇ A more preferable range is, independently of each other, 0.10 ≤ x ａｖｇ ≤ 0.20, 0.00 ≤ y ａｖｇ ≤ 0.02, 0.00 ≤ z ａｖｇ ≤0.05, 0.10 ≤s ａｖｇ The value is ≤ 0.15.

[0026] (2) Upper Layer The following description regarding the upper layer is common to the first to third embodiments. The upper layer is in contact with the lower layer and is the layer directly above the lower layer, providing abrasion resistance to the coating layer, and is preferably made of a nitrogen-containing compound (nitride). Average thickness of the upper layer (When the upper layer is composed of multiple layers, the average thickness of the sum of these multiple layers is preferably 0.3 to 6.0 μm. The reason for setting the average thickness of the upper layer within this range is as follows: If the average thickness is less than 0.3 μm, the abrasion resistance of the coating layer cannot be ensured, while if it exceeds 6.0 μm, the chipping resistance of the coating layer cannot be ensured. A more preferable range for the average thickness of the upper layer is 1.5 to 4.0 μm.

[0027] (2-1) Upper layer of the first embodiment The compound constituting the upper layer of the first embodiment is of the formula: Al ｄ M1 １－ｄ N(M1 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W, and the average value of d) ａｖｇ is 0.20 ≤ d ａｖｇ It has a composition that satisfies ≤ 0.80. Average value d ａｖｇ The reason for setting this range is that if it is smaller than the lower limit, the wear resistance of the upper layer will be insufficient, and if it exceeds the upper limit, a soft hexagonal crystal will form in the upper layer, reducing its hardness. Average value d ａｖｇ is 0.40 ≤ d ａｖｇ It is more preferable that the value be ≤ 0.70. ｄａｖｇ M1 １－ｄａｖｇ The atomic ratio of ) to N is preferably 1.0:0.9 to 1.0:1.1.

[0028] (2-2) Upper layer of the second embodiment The compound constituting the upper layer of the second embodiment consists of a first upper sublayer and a second upper sublayer directly above the first upper sublayer, providing the coating layer with abrasion resistance as well as fracture resistance. The first upper sublayer is made of a compound of the formula: Al ｄ１ M1 １－ｄ１ N(M1 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W, and the average value of d1 is d1 ａｖｇ 0.20 ≤ d1 ａｖｇ The second upper sublayer has a composition represented by the formula: Al (satisfying ≤ 0.80), and the second upper sublayer is represented by the formula: Alｄ２ M2 １－ｄ２ N(M2 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W, and the average value of d2 is d2) ａｖｇ 0.20 ≤ d2 ａｖｇ It has a composition that satisfies ≤0.80. However, M1 and M2 are different (M1 and M2 are different if one or more elements in M2 are different from the elements in M1, and d1 ａｖｇ and d2 ａｖｇ (These may be the same or different) or M1 and M2 are the same and 0.15 ≤ |d1 ａｖｇ -d2 ａｖｇ | ≤ 0.60. Average value d1 ａｖｇ and average value d2 ａｖｇ The reason for this range is that if it is less than 0.15, the abrasion resistance of the upper layer is insufficient, and if it exceeds 0.60, either the first upper sublayer or the second upper sublayer will have 0.20 ≤ d1 ａｖｇ ≤0.80, 0.20 ≤d ２ａｖｇ Outside the range of ≤0.80, the coating layer fails to exhibit wear resistance, resulting in a decrease in hardness. |d1 ａｖｇ -d2 ａｖｇ A more preferable range for | is 0.20 ≤ |d1 ａｖｇ -d2 ａｖｇ | ≤ 0.40.

[0029] Average value d1 ａｖｇ and average value d2 ａｖｇ Each of these is independently 0.40 ≤ d1 ａｖｇ ≤0.70, 0.40 ≤d² ａｖｇ It is more preferable that the range is ≤0.70. ｄ１ａｖｇ M1 １－ｄ１ａｖｇ ) and the atomic ratio of N and (Al ｄ２ａｖｇ M1 １－ｄ２ａｖｇ The atomic ratio of ) to N is preferably 1.0:0.9 to 1.0:1.1 in all cases. More preferably, the lower limit of the average thickness of both the first upper sublayer and the second upper sublayer is 0.1 μm.

[0030] (2-3) Upper layer of the third embodiment The upper layer of the third embodiment consists of an alternating laminate. The alternating laminate consists of alternating layers of α sublayers and β sublayers, each having an average thickness of 3 to 20 nm, the average thickness of the alternating laminate is 0.3 to 6.0 μm, and the α sublayer is made of Al ｐ Ti １－ｐ N(mean value of p) ａｖｇ 0.30 ≤ p ａｖｇ The β sublayer consists of a compound having a composition (satisfying ≤ 0.60) represented by the formula: Al ｑ Ti １－ｑ―ｍ M3 ｍ N(M3 is at least one element selected from the elements Cr, Mo, Ta, B, Si, and W, and the mean value of q is q ａｖｇ 0.50 ≤ q ａｖｇ ≤ 0.80, average value of m ａｖｇ 0.01 ≤ m ａｖｇ ≤ 0.20, q ａｖｇ -p ａｖｇ It has a composition that satisfies ≥ 0.01 for each component.

[0031] The average value of Al in the alpha sublayer, p ａｖｇ , β sublayer Al average value q ａｖｇ and the average value of M m ａｖｇ The reason for setting the range as described above is as follows: p ａｖｇ and q ａｖｇ If the values ​​are smaller than the lower limit, the wear resistance of the upper layer decreases. Conversely, if the values ​​exceed the upper limit, a soft hexagonal crystal structure is formed, reducing the hardness of the alternating laminate. ａｖｇ If the value is smaller than the lower limit, the heat resistance and wear resistance of the alternating laminate will be insufficient, and if it exceeds the upper limit, the wear resistance of the alternating laminate will decrease. Also, q ａｖｇ -p ａｖｇ If the value ≥ 0.01 is not satisfied, the improvement in wear resistance of the alternating laminate is insufficient. ａｖｇ , q ａｖｇ , m ａｖｇ The preferred ranges for each are independently 0.40 ≤ p ａｖｇ ≤0.55, 0.60 ≤q ａｖｇ ≤0.75, 0.05 ≤m ａｖｇ ≤ 0.15, q ａｖｇ -p ａｖｇThe value is ≥ 0.10.

[0032] The reason why the average thickness of each α sublayer and β sublayer is 3 to 20 nm is as follows: If it is less than 3 nm, the wear resistance of the upper layer decreases, while if it exceeds 20 nm, the upper layer cannot sufficiently suppress the propagation of cracks that occur during cutting, making it easier for defects due to crack propagation to occur. The average thickness of each α sublayer and β sublayer is more preferably 5 to 15 nm.

[0033] The reason why the average thickness of the upper layer, which is an alternating lamination composed of α sublayers and β sublayers, is preferably 0.3 to 6.0 μm is as follows: If it is less than 0.3 μm, the abrasion resistance of the upper layer decreases, while if it exceeds 6.0 μm, the fracture resistance of the upper layer becomes insufficient. A more preferable range for the average thickness of the upper layer is 1.5 to 4.0 μm.

[0034] There are no particular restrictions on the number of α and β sublayers, as long as the average thickness per layer of each α and β sublayer, and the average thickness of the upper layer (alternating layers) are within the aforementioned ranges. Furthermore, the layer adjacent to the lower layer and the outermost layer of the alternating layers can be either an α or β sublayer. The number of α and β sublayers do not have to be the same. A more preferable number of layers is 200 to 600 in total for α and β sublayers. This total is calculated by dividing the average thickness of the upper layer by the sum of the average thicknesses of the α and β sublayers, and rounding to the first decimal place.

[0035] (4) Although the lower and upper layers (including the first upper sublayer, the second upper sublayer, and the alternating layers) are formed in a manner that prevents the formation of compounds other than those mentioned above, slight disturbances in the film formation conditions (e.g., temperature changes, changes in the flow rate of the deposition gas, changes in furnace pressure, changes in the target voltage, etc.) may cause compounds different from these compounds (referred to as unintended compounds) to be formed unintentionally in parts. That is, in the claims and specification, when it is stated that "Layer A has a composition represented by ...X", it is equivalent to saying that "Layer A consists of a compound having the composition X", but Layer A may partially contain this unintended compound in addition to the compound having the composition X. Even if the unintended compound is present, it does not affect the physical properties of either the lower or upper layer, and the aforementioned problem to be solved is resolved.

[0036] 2. Substrate (1) The compositional substrate is a WC-based cemented carbide. A WC-based cemented carbide is a alloy whose hard phase component is mainly W carbide (not limited to stoichiometric composition), with iron group elements such as Co as the bonding phase component, and may also contain carbides (not limited to stoichiometric composition) containing one or two of Cr, Ta, Nb, and V.

[0037] (2) The shape of the base material is not particularly restricted as long as it is a shape that can be used as a cutting tool, and examples include the shape of an insert and the shape of a drill.

[0038] 3. Measurement Method (3-1) Measurement of the Average Thickness and Average Composition of the Lower Layer In any of the first to third embodiments, the measurements can be taken using an Energy Dispersive X-ray Spectrometer (EDS) attached to a Transmission Electron Microscope (TEM). Specifically, first, a focused ion beam (FIB) processing machine is used to create a longitudinal section of a thin film of approximately 30 to 100 nm, with the observation plane perpendicular to the substrate surface. The longitudinal section of this coated tool is then observed (in the case of an insert, minute irregularities on the substrate surface are ignored and it is considered a flat surface, and the section is perpendicular to this surface; in the case of a shaft tool such as a drill, the section is perpendicular to the shaft).

[0039] First, multiple rectangular observation fields are set in this longitudinal section, with dimensions such as "length: thickness including the entire coating layer, width: 1.0 μm". High-angle scattering annular dark-field scanning transmission microscope (HAADF-STEM) images are obtained for these observation fields at a predetermined magnification. Then, the average values ​​obtained from measurements taken at five or more locations in each observation field are further averaged to obtain the average thickness and average composition.

[0040] (1) Measurement of the average thickness of the lower layer (i) Observe the field of view with TEM at 1000x magnification to obtain a first HAADF-STEM image. From this image, estimate the substrate surface (referred to as the substrate provisional surface) and the interface (provisional layer interface) between the lower layer and the upper layer (the first upper sublayer in the second embodiment).

[0041] (ii) When the lower layer is thin (when the interface between the lower and upper layers (temporary layer interface) is estimated from the first HAADF-STEM image and the thickness of the lower layer is estimated to be 100 nm or less), a second HAADF-STEM image is obtained at an observation magnification of 200,000x and the substrate temporary surface and its vicinity are observed for line analysis. When the lower layer is thick (when the interface between the lower and upper layers is estimated from the first HAADF-STEM image and the thickness of the lower layer is estimated to be more than 100 nm), the substrate temporary surface and its vicinity are observed for line analysis relative to the first HAADF-STEM image.

[0042] (iii) Line analysis (TEM-EDS analysis) of the substrate pseudo-surface and its vicinity is performed at a measurement interval of 2 nm, starting from approximately 2 μm inside the substrate from the substrate pseudo-surface toward the coating layer surface. The line analysis point where Ti ≥ 5 atomic% is first satisfied is defined as a point on the interface between the substrate and the lower layer. Line analysis is performed at 10 or more locations at 50 nm intervals parallel to this pseudo-surface in the first and second HAADF-STEM images. The points thus obtained are approximated by least squares to obtain an average straight line, and this average straight line (hereinafter referred to as the "substrate surface line") is considered to be the surface of the substrate. The direction perpendicular to this substrate surface line is considered to be the thickness direction of the coating layer.

[0043] (iv) The interface between the lower layer and the upper layer is determined as follows: Observe the provisional layer interface and its vicinity estimated in (ii) above for line analysis. That is, when the lower layer is thin, a second HAADF-STEM image is obtained with an observation magnification of 200,000x, and the provisional layer interface and its vicinity are observed for line analysis. When the lower layer is thick, observe the vicinity of the provisional lower-upper layer interface for line analysis relative to the first HAADF-STEM image. Observation of the provisional layer interface and its vicinity by line analysis is performed at a measurement interval of 2 nm from the substrate surface line toward the coating layer surface.

[0044] Line analysis is performed on Al, and the line analysis point where Al ≥ 5 atomic percent is first satisfied is defined as the boundary point between the lower and upper layers. This measurement is performed at 10 or more locations parallel to the substrate surface at 50 nm intervals, and a boundary point is determined for each location. These boundary points are approximated by least squares to obtain the average straight line (hereinafter referred to as the "interface line between the lower and upper layers"), and this is defined as the interface between the lower and upper layers. The average thickness of the lower layer is determined by dividing the substrate surface line into 10 equal parts, extending these points in the thickness direction of the coating layer, finding the length at which they intersect with the interface line between the lower and upper layers, and taking the average of these lengths as the average thickness of the lower layer.

[0045] (2) Measurement of the average composition of the lower layer The average composition of the compound in the lower layer is determined by setting an observation field within the region considered to be the lower layer based on the substrate surface line and the average thickness of the lower layer, where the vertical direction is 90% of the average thickness of the lower layer and the horizontal direction is 20 times or more of the average thickness of the lower layer, and measuring W, Ti, C, A, and N (A is an element contained in the substrate from Cr, Ta, Nb, and V) from 10 or more TEM-EDS measurement points and calculating the average value. At this time, elements that are less than 0.01 atomic percent (percentage of the total number of atoms observed) are ignored.

[0046] (3-3) Measurement of the average thickness and average composition of the upper layer (3-3-1) First embodiment (1) Average thickness of the upper layer The upper edge of the upper layer is estimated from the first HAADF-STEM image. Line composition analysis is performed at a measurement interval of 2 nm from the interface line between the lower layer and the upper layer determined in (iv) above, in the thickness direction of the coating layer to the upper edge of the upper layer, and the point where Al first satisfies less than 0.01 atomic percent is defined as the upper edge point of the upper layer. This line composition analysis is performed at 10 or more locations parallel to the surface of the substrate at 50 nm intervals, and the average line (hereinafter referred to as the "upper edge line of the upper layer") is obtained by approximating this upper edge point using the least squares method. The average thickness of the upper layer is determined by finding points that divide the upper edge line of the upper layer into 10 equal parts, extending these points toward the substrate in the thickness direction of the coating layer, finding the length where it intersects with the substrate surface line, and taking the difference between the average length of that length and the average thickness of the lower layer as the average thickness of the upper layer.

[0047] (2) Average composition of the compounds in the upper layer is determined by setting an observation field within the region considered to be the upper layer, where the vertical direction is 90% of the average thickness of the upper layer and the horizontal direction is 5 times or more of the average thickness of the upper layer, and measuring Al, M1, and N (M1 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W) from 10 or more TEM-EDS measurement points within this observation field and calculating the average value. At this time, elements that are less than 0.01 atomic percent (percentage of the total number of atoms observed) are ignored.

[0048] (3-3-2) Second Embodiment (1) Average Thickness (1-1) When M1 and M2 are different, in the thickness direction of the coating layer determined in (iii) above, line analysis is performed at a measurement interval of 2 nm from the interface line between the lower layer and the upper layer to the point estimated to be the upper end of the second upper sublayer in the first HAADF-STEM image, for one element 1 that is not included in M1 of the first upper sublayer but is included in M2 of the second upper sublayer by TEM-EDS, up to the point estimated to be the upper end of the upper layer in the thickness direction of the coating layer. When adjacent analysis points are connected by a straight line (line segment) in the line analysis, the midpoint between the ends of the line segment with the greatest slope is determined as the boundary point between the first upper sublayer and the second upper sublayer.

[0049] This line analysis is performed at 10 or more points at 50 nm intervals in a direction parallel to the substrate surface line, and the boundary point is determined for each point. The mean line (hereinafter referred to as the "interface line between the first upper sublayer and the second upper sublayer") obtained from these boundary points is determined by the least squares method, and this is taken as the interface between the first upper sublayer and the second upper sublayer. In this line analysis, the point where all of the M2 elements contained in the second upper sublayer first satisfy the condition of less than 0.01 atomic percent is taken as the upper end point of the second upper sublayer. Since this line composition analysis is performed at 10 or more locations at 50 nm intervals parallel to the substrate surface line, the mean line (hereinafter referred to as the "upper end line of the second upper sublayer") is determined by approximating this upper end point by the least squares method.

[0050] The average thickness of the first upper sublayer is determined by finding points that divide the interface line between the first upper sublayer and the second upper sublayer into 10 equal parts, extending these points toward the substrate in the thickness direction of the coating layer to find the length where it intersects the substrate surface line, and then determining the difference between the average length of this length and the average thickness of the lower layer. The average thickness of the second upper sublayer is determined by finding points that divide the upper end line of the second upper sublayer into 10 equal parts, extending these points toward the substrate in the thickness direction of the coating layer to find the length where it intersects the substrate surface line, and then subtracting the average thickness of the lower layer and the average thickness of the first upper sublayer from the average length of this length.

[0051] (1-2) When M1 and M2 are the same, line analysis is performed on Al at a measurement interval of 2 nm from the interface line between the lower layer and the upper layer in the thickness direction of the coating layer determined in (iii) above to the point estimated to be the upper end of the second upper sublayer in the first HAADF-STEM image, and the boundary point between the first upper sublayer and the second upper sublayer is determined to be the midpoint between the ends of the line segment with the greatest slope when adjacent analysis points are connected by a straight line (line segment).

[0052] This analysis is performed at 10 points at 50 nm intervals in a direction parallel to the substrate surface line, and the boundary point is determined for each point. The mean line (hereinafter referred to as the "interface line between the first upper sublayer and the second upper sublayer") obtained from these boundary points is determined by the least squares method, and this is taken as the interface between the first upper sublayer and the second upper sublayer. In this line composition analysis, the point where Al first satisfies less than 0.01 atomic percent is taken as the upper end point of the second upper sublayer. Since this line composition analysis is performed at 10 or more locations at 50 nm intervals parallel to the substrate surface, the mean line (hereinafter referred to as the "upper end line of the second upper sublayer") is determined by approximating this upper end point by the least squares method.

[0053] The average thickness of the first upper sublayer is determined by finding points that divide the interface line between the first upper sublayer and the second upper sublayer into 10 equal parts, extending these points toward the substrate in the thickness direction of the coating layer to find the length where it intersects the substrate surface line, and then determining the difference between the average length of this length and the average thickness of the lower layer. The average thickness of the second upper sublayer is determined by finding points that divide the upper end line of the second upper sublayer into 10 equal parts, extending these points toward the substrate in the thickness direction of the coating layer to find the length where it intersects the substrate surface line, and then subtracting the average thickness of the lower layer and the average thickness of the first upper sublayer from the average length of this length.

[0054] (2) Average composition The average composition of the compounds in the first upper sublayer and the second upper sublayer is determined by setting an observation field within the regions considered to be the first upper sublayer and the second upper sublayer, where the vertical direction is 90% of the average thickness of the first upper sublayer and the second upper sublayer, and the horizontal direction is 5 times or more of the average thickness of the first upper sublayer and the second upper sublayer, and measuring Al, M1, M2, and N (M1 and M2 are at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, and W, respectively) at 10 or more measurement points and calculating the average value. At this time, elements that are less than 0.01 atomic percent (percentage of the total number of atoms observed) are ignored.

[0055] (3-3-3) Third Embodiment (1) Average Thickness The average thickness of the entire upper layer is determined in the same way as the average thickness of the upper layer in Embodiment 1. The average thickness of the α sublayer and β sublayer in the upper layer of the third embodiment is determined by identifying a region in the third HAADF-STEM image (observation magnification: 2 million times) that contains at least 10 layers, preferably 50 or more of these layers (a length in which at least 10, preferably 50, maximum values ​​of atomic %m of M3 can be observed. Atomic %(m) of M3 is the number of atoms of M3 relative to the total number of atoms of Al, Ti, N and M3), and performing line analysis in this region at a measurement interval of 2 nm. The maximum and minimum values ​​of m are determined, and the point that gives the midpoint between adjacent maximum and minimum values ​​is defined as the lamination interface between the α sublayer and the β sublayer. Regions between adjacent lamination interfaces where the value of m is smaller than the midpoint between the maximum and minimum values ​​are identified as the α sublayer, and regions where it is larger are identified as the β sublayer. The average thickness is then calculated by averaging the thicknesses of each layer.

[0056] (2) Average composition The average composition of the α sublayer and β sublayer is determined by performing line analysis at any position in the thickness direction of the α sublayer and β sublayer obtained above, in a direction parallel to the substrate surface line (the length in the parallel direction shall be at least 20 times the average thickness of the α sublayer and β sublayer, respectively). Line analysis is performed on at least 10 layers each of the α sublayer and β sublayer, measuring Al, Ti, M3, and N (M3 is at least one element selected from Cr, Mo, Ta, B, Si, and W), and the average composition is obtained by arithmetic mean of the measurement results. Elements that are less than 0.01 atomic percent (percentage of the total number of atoms observed) are ignored.

[0057] 4. Manufacturing Method A typical manufacturing method for the coated tool according to this embodiment is shown below. A substrate made of WC-based cemented carbide of a predetermined shape is prepared, and a lower layer and an upper layer are deposited on the substrate using a cathode ray emission (CAE) type PVD apparatus (hereinafter referred to as "PVD apparatus"). The lower layer is deposited at a low temperature and with a bias voltage within a specific range to diffuse the substrate components into the lower layer.

[0058] (1) Film deposition of the lower layer (1st to 3rd embodiments) Target: WTi corresponding to the composition of the lower layer Cathode current: 50A to 300A Bias voltage: -800 to -1000V Gas type: Ar + N２ Or N ２ Gas partial pressure: N ２ 0.5–3.0 Pa Ar 0.5–3.0 Pa (Gas partial pressure is independent of gas type) Deposition temperature (furnace temperature): 300–600°C Deposition time: 10–60 minutes Rotary table rotation speed: 1.5–4.0 rpm (1 / min)

[0059] (2) Depending on the layer structure of the upper layer film formation, the following can be given as examples.

[0060] (2-1) Target of the first embodiment: AlM1 target corresponding to the composition of the upper layer Cathode current: 50A to 300A Bias voltage: -20 to -500V Gas conditions: N ２ Pressure: 0.5–7.0 Pa; Deposition temperature (furnace temperature): 300–600°C; Deposition time: 80–300 minutes; Rotary table rotation speed: 1.5–4.0 rpm (1 / min)

[0061] (2-2) Second embodiment target: AlM1 target and AlM2 target corresponding to the composition of the first upper sublayer and the second upper sublayer, respectively. Cathode current: 50A to 300A Bias voltage: -20 to -500V Gas conditions: N ２ Pressure: 0.5–7.0 Pa; Deposition temperature (furnace temperature): 300–600°C; Deposition time: 80–300 minutes; Rotary table rotation speed: 1.5–4.0 rpm (1 / min)

[0062] (2-3) Third embodiment target: Two types of targets, AlTi and AlTiM3, corresponding to the α sublayer and β sublayer compositions of the upper layer, respectively. Cathode current: 50A to 300A Bias voltage: -20 to -500V Gas conditions: N ２ Pressure: 0.5–7.0 Pa; Deposition temperature: 300–600°C; Deposition time: 80–300 minutes; Rotary table rotation speed: 1.5–4.0 rpm (1 / min)

[0063] The above description includes the following features: (Note 1) A substrate containing a WC-based cemented carbide, and a coating layer provided on the substrate, comprising a lower layer and an upper layer, wherein the lower layer has an average thickness of 5 to 500 nm, Formula: W ｘ Ti １－ｘ－ｙ－ｚ－ｓ A ｙ Cｚ N ｓ (A is at least one element selected from the group Cr, Ta, Nb, V, and the mean value of x is x) ａｖｇ x ≤ 0.05 ａｖｇ ≤ 0.30, mean value of y ａｖｇ is 0.00 ≤ y ａｖｇ ≤ 0.05, mean value of z ａｖｇ is 0.00 ≤ z ａｖｇ ≤ 0.10, mean value of s ａｖｇ is 0.05 ≤ s ａｖｇ ≤ 0.30, x ａｖｇ ≥ 2 × z ａｖｇ The composition is represented by (satisfying each of the following conditions), and the upper layer has an average thickness of 0.3 to 6.0 μm, and the formula is Al ｄ M1 １－ｄ N(M1 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W, and the mean value of d) ａｖｇ is 0.20 ≤ d ａｖｇ A surface-coated cutting tool characterized by having a composition that satisfies ≤0.80. (Note 2) The above x ａｖｇ is 0.10 ≤ x ａｖｇ A surface-coated cutting tool as described in Appendix 1, characterized in that it satisfies ≤ 0.20. (Appendix 3) The y ａｖｇ 0.00 ≤ y ａｖｇ A surface-coated cutting tool according to Appendix 1 or 2, characterized in that it satisfies ≤ 0.02. (Appendix 4) The z ａｖｇ is 0.00 ≤ z ａｖｇ A surface-coated cutting tool according to any one of the appendices 1 to 3, characterized in that it satisfies ≤ 0.05. (Appendix 5) The s ａｖｇ is 0.10 ≤ s ａｖｇ A surface-coated cutting tool as described in any of Appendix 1 to 4, characterized in that it satisfies ≤0.15. (Appendix 6) The d ａｖｇ is 0.40 ≤ d ａｖｇA surface-coated cutting tool according to any one of Appendix 1 to 5, characterized in that it satisfies ≤0.70. (Appendix 7) A surface-coated cutting tool according to any one of Appendix 1 to 6, characterized in that the upper layer has an average thickness of 1.5 to 4.0 μm. (Appendix 8) A substrate containing a WC-based cemented carbide, and a coating layer provided on the substrate, comprising a lower layer and an upper layer, wherein the lower layer has an average thickness of 5 to 500 nm, Formula: W ｘ Ti １－ｘ－ｙ－ｚ－ｓ A ｙ C ｚ N ｓ (A is at least one element selected from the group Cr, Ta, Nb, V, and the mean value of x is x) ａｖｇ x ≤ 0.05 ａｖｇ ≤ 0.30, mean value of y ａｖｇ is 0.00 ≤ y ａｖｇ ≤ 0.05, mean value of z ａｖｇ is 0.00 ≤ z ａｖｇ ≤ 0.10, mean value of s ａｖｇ is 0.05 ≤ s ａｖｇ ≤ 0.30, x ａｖｇ ≥ 2 × z ａｖｇ The upper layer has a composition represented by (satisfying the above), the upper layer has an average thickness of 0.3 to 6.0 μm, and consists of a first upper sublayer and a second upper sublayer on the first upper sublayer, the first upper sublayer is made of a material of the formula: Al ｄ１ M1 １－ｄ１ N(M1 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W, and the average value of d1 is d1 ａｖｇ 0.20 ≤ d1 ａｖｇ The second upper sublayer has a composition represented by the formula: Al (satisfying ≤ 0.80), and the second upper sublayer is represented by the formula: Al ｄ２ M2 １－ｄ２ N(M2 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W, and the average value of d2 is d2) ａｖｇ 0.20 ≤ d2 ａｖｇ The condition ≤ 0.80 is satisfied, where M1 and M2 are different or M1 and M2 are the same, and 0.15 ≤ |d1 ａｖｇ -d2 ａｖｇ A surface-coated cutting tool characterized by having a composition represented by | ≤ 0.60. (Note 9) The above x ａｖｇis 0.10 ≤ x ａｖｇ A surface-coated cutting tool as described in Appendix 8, characterized in that it satisfies ≤ 0.20. (Appendix 10) The y ａｖｇ 0.00 ≤ y ａｖｇ A surface-coated cutting tool according to Appendix 8 or 9, characterized in that it satisfies ≤0.02. (Appendix 11) The z ａｖｇ is 0.00 ≤ z ａｖｇ A surface-coated cutting tool according to any one of appendices 8 to 10, characterized in that it satisfies ≤0.05. (Appendix 12) The s ａｖｇ is 0.10 ≤ s ａｖｇ A surface-coated cutting tool according to any one of appendices 8 to 11, characterized in that it satisfies ≤0.15. (Appendix 13) The d1 ａｖｇ 0.40 ≤ d1 ａｖｇ A surface-coated cutting tool according to any one of appendices 8 to 12, characterized in that it satisfies ≤0.70. (Appendix 14) The above d2 ａｖｇ 0.40 ≤ d2 ａｖｇ A surface-coated cutting tool as described in any of Appendix 8 to 13, characterized by satisfying ≤0.70. (Appendix 15) 0.20 ≤ |d1 ａｖｇ -d2 ａｖｇ A surface-coated cutting tool according to any one of appendices 8 to 14, characterized in that it satisfies | ≤ 0.40. (Appendix 16) A surface-coated cutting tool according to any one of appendices 8 to 15, characterized in that the upper layer has an average thickness of 1.5 to 4.0 μm. (Appendix 17) A substrate containing a WC-based cemented carbide, and a coating layer provided on the substrate, comprising a lower layer and an upper layer, wherein the lower layer has an average thickness of 5 to 500 nm, Formula: W ｘ Ti １－ｘ－ｙ－ｚ－ｓ A ｙ C ｚ N ｓ (A is at least one element selected from the group Cr, Ta, Nb, V, and the mean value of x is x) ａｖｇ x ≤ 0.05 ａｖｇ ≤ 0.30, mean value of y ａｖｇ is 0.00 ≤ y ａｖｇ ≤ 0.05, mean value of z ａｖｇ is 0.00 ≤ z ａｖｇ ≤ 0.10, mean value of s ａｖｇ is 0.05 ≤ sａｖｇ ≤ 0.30, x ａｖｇ ≥ 2 × z ａｖｇ The laminate has a composition represented by (satisfying each of the following conditions), the upper layer has an average thickness of 0.3 to 6.0 μm, and is composed of alternating α sublayers and β sublayers with an average thickness of 3 to 20 nm per layer, wherein the α sublayer is composed of Al ｐ Ti １－ｐ N(mean value of p) ａｖｇ 0.30 ≤ p ａｖｇ The β sublayer has a composition that satisfies ≤ 0.60, and the β sublayer is made of Al ｑ Ti １－ｑ―ｍ M3 ｍ N(M3 is at least one element selected from the group Cr, Mo, Ta, B, Si, W, and the mean value of q is q ａｖｇ 0.50 ≤ q ａｖｇ ≤ 0.80, average value of m ａｖｇ 0.01 ≤ m ａｖｇ ≤ 0.20, q ａｖｇ -p ａｖｇ A surface-coated cutting tool characterized by having a composition that satisfies ≥ 0.01 for each element. (Note 18) The above x ａｖｇ is 0.10 ≤ x ａｖｇ A surface-coated cutting tool as described in Appendix 17, characterized in that it satisfies ≤0.20. (Appendix 19) The aforementioned y ａｖｇ 0.00 ≤ y ａｖｇ A surface-coated cutting tool according to Appendix 17 or 18, characterized in that it satisfies ≤ 0.02. (Appendix 20) The z ａｖｇ is 0.00 ≤ z ａｖｇ A surface-coated cutting tool according to any one of appendices 17 to 19, characterized in that it satisfies ≤0.05. (Appendix 21) The s ａｖｇ is 0.10 ≤ s ａｖｇ A surface-coated cutting tool according to any one of appendices 17 to 20, characterized in that it satisfies ≤ 0.15. (Appendix 22) The above p ａｖｇ 0.40 ≤ p ａｖｇ A surface-coated cutting tool according to any one of the appendices 17 to 21, characterized in that it satisfies ≤0.55. (Appendix 23) The q ａｖｇ 0.60 ≤ q ａｖｇA surface-coated cutting tool according to any one of the appendices 17 to 22, characterized in that it satisfies ≤0.75. (Appendix 24) The aforementioned m ａｖｇ 0.05 ≤ m ａｖｇ A surface-coated cutting tool according to any one of the appendices 17 to 23, characterized in that it satisfies ≤ 0.15. (Appendix 25) The q ａｖｇ -p ａｖｇ is, q ａｖｇ -p ａｖｇ A surface-coated cutting tool according to any one of appendices 17 to 24, characterized in that it satisfies ≥ 0.10. (Appendix 26) A surface-coated cutting tool according to any one of appendices 17 to 25, characterized in that the upper layer has an average thickness of 1.5 to 4.0 μm.

[0064] Next, we will describe an example. As an example, we will describe an application to a coated tool with an insert shape using a WC-based cemented carbide as the base material, but as mentioned above, the shape of the base material may be a drill, end mill, etc.

[0065] 1. The raw material powders used to prepare the substrate are Co powder, TiC powder, VC powder, TaC powder, NbC powder, and Cr. ３ C ２ Powder and WC powder were prepared. These raw material powders were blended to the composition shown in Table 1, wax was added, and the mixture was wet-mixed in a ball mill for 72 hours. After drying under reduced pressure, the mixture was formed into compacted bodies at a pressure of 100 MPa. These compacted bodies were sintered at 1400°C for 1 hour under a vacuum atmosphere of 6 Pa, and then processed to the predetermined dimensions, i.e., the insert shape according to the ANSI standard CNMG432, to produce base bodies 1 to 3.

[0066] 2. Following film formation, substrates 1 to 3 were ultrasonically cleaned in acetone and dried, then mounted along their outer circumference at a predetermined radial distance from the central axis on a rotating table within the apparatus. A target of a predetermined composition was also placed as the cathode electrode (evaporation source).

[0067] Next, the PVD apparatus was evacuated and maintained at a vacuum of 0.3 Pa or less while the inside of the apparatus was heated to 600°C with a heater. Then, a DC bias voltage of -1000V was applied to the substrate rotating on a rotary table, and a current of 100A was passed between the cathode electrode and the anode electrode to bombard the substrate surface.

[0068] Next, film deposition was performed using the film deposition conditions shown in Tables 2, 3, 6, and 7 to obtain tools for Examples 1 to 5 and 11 to 20, corresponding to the first and second embodiments shown in Tables 10 and 11, and tools for Examples 6 to 10 and 21 to 27, corresponding to the third embodiment shown in Tables 14 and 15. On the other hand, as comparative examples, film deposition was performed using the film deposition conditions shown in Tables 4, 5, 8, and 9 to obtain tools for Comparative Examples 1 to 5 and 11 to 20, shown in Tables 12 and 13, and tools for Comparative Examples 6 to 10 and 21 to 27, shown in Tables 16 and 17.

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086] In Tables 10-13, there are no "-" and "0.0", and in Tables 10, 12 and 14, 16, there are no "x" ａｖｇ ≥ 2 × z ａｖｇ In the column "Does it satisfy the condition?", "○" indicates that it is satisfied, and "×" indicates that it is not satisfied. Tables 15 and 17, "q ａｖｇ -p ａｖｇ In the column for "≥0.01", "〇" indicates that the condition is met, and "×" indicates that it is not met.

[0087] The following cutting tests were performed on the tools of Examples 1-10 and 11-27, and Comparative Examples 1-10 and 11-27. The flank wear width and the presence or absence of chipping were measured every minute. The results are shown in Table 18.

[0088] Cutting Test: Stainless Steel Turning Workpiece Material: SUS304 3-piece slit material φ200mm x length 600mm (slit width 20mm x depth 50mm) Tool Shape: DCLNL2525M12 Cutting Speed: vc = 125 m / min Depth of Cut: 2.0 mm Feed Rate: 0.25 mm / tooth Measurement of flank wear after 10 minutes of cutting

[0089]

[0090] Every minute after the start of the cutting test, the presence or absence of chipping and delamination caused by chipping was visually observed, and the flank wear width was measured. The lifespan was defined as the point at which the flank wear width reached 0.3 mm or more. In Table 18, "*" indicates that the service life was reached (chipping was confirmed) before the specified cutting time (10 minutes) in the cutting test, and the time (minutes) at which the service life was reached is shown.

[0091] As is clear from Table 18, in all of the examples, the wear width of the flank surface was small and no chipping occurred. However, in the comparative example, the wear width of the flank surface was large and chipping occurred. This indicates that all of the examples have excellent wear resistance and fracture resistance even when subjected to cutting processes for stainless steel and other materials.

[0092] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is indicated by the claims rather than by the embodiments described herein, and all modifications within the scope are intended to be in the sense of equivalents of the claims.

[0093] 1. Substrate 2. Covering layer 3. Lower layer 4. Upper layer 5. First upper sublayer 6. Second upper sublayer 7. α sublayer 8. β sublayer

Claims

1. A substrate containing a WC-based superhard alloy, and provided on the substrate, including a coating layer composed of a lower layer and an upper layer, the lower layer having an average thickness of 5 to 500 nm, and the formula: W ｘ Ti １－ｘ－ｙ－ｚ－ｓ A ｙ C ｚ N ｓ (A is at least one element selected from the group of Cr, Ta, Nb, V, and the average value x of x ａｖｇ is 0.05 ≤ x ａｖｇ ≤ 0.30, the average value y of y ａｖｇ is 0.00 ≤ y ａｖｇ ≤ 0.05, the average value z of z ａｖｇ is 0.00 ≤ z ａｖｇ ≤ 0.10, the average value s of s ａｖｇ is 0.05 ≤ s ａｖｇ ≤ 0.30, x ａｖｇ ≥ 2 × z ａｖｇ are each satisfied), and having a composition represented by the formula: Al ｄ M1 １－ｄ N (M1 is at least one element selected from the group of Ti, Cr, Ta, B, Si, Mo, W, and the average value d of d ａｖｇ is 0.20 ≤ d ａｖｇ ≤ 0.80 is satisfied), a surface-coated cutting tool characterized by having a composition represented by the formula.

2. A substrate containing a WC-based cemented carbide, and a coating layer provided on the substrate, comprising a lower layer and an upper layer, wherein the lower layer has an average thickness of 5 to 500 nm, Formula: W ｘ Ti １－ｘ－ｙ－ｚ－ｓ A ｙ C ｚ N ｓ (A is at least one element selected from the group Cr, Ta, Nb, V, and the mean value of x is x) ａｖｇ x ≤ 0.05 ａｖｇ ≤ 0.30, mean value of y ａｖｇ is 0.00 ≤ y ａｖｇ ≤ 0.05, mean value of z ａｖｇ is 0.00 ≤ z ａｖｇ ≤ 0.10, mean value of s ａｖｇ is 0.05 ≤ s ａｖｇ ≤ 0.30, x ａｖｇ ≥ 2 × z ａｖｇ The upper layer has a composition represented by (satisfying the above), the upper layer has an average thickness of 0.3 to 6.0 μm, and consists of a first upper sublayer and a second upper sublayer on the first upper sublayer, the first upper sublayer is made of a material of the formula: Al ｄ１ M1 １－ｄ１ N(M1 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W, and the average value of d1 is d1 ａｖｇ 0.20 ≤ d1 ａｖｇ The second upper sublayer has a composition represented by the formula: Al (satisfying ≤ 0.80), and the second upper sublayer is represented by the formula: Al ｄ２ M2 １－ｄ２ N(M2 is at least one element selected from the group Ti, Cr, Ta, B, Si, Mo, W, and the average value of d2 is d2) ａｖｇ 0.20 ≤ d2 ａｖｇ The condition ≤ 0.80 is satisfied, where M1 and M2 are different or M1 and M2 are the same, and 0.15 ≤ |d1 ａｖｇ -d2 ａｖｇ A surface-coated cutting tool characterized by having a composition represented by | ≤ 0.

60.

3. A substrate containing a WC-based cemented carbide, and a coating layer provided on the substrate, comprising a lower layer and an upper layer, wherein the lower layer has an average thickness of 5 to 500 nm, Formula: W ｘ Ti １－ｘ－ｙ－ｚ－ｓ A ｙ C ｚ N ｓ (A is at least one element selected from the group Cr, Ta, Nb, V, and the mean value of x is x) ａｖｇ x ≤ 0.05 ａｖｇ ≤ 0.30, mean value of y ａｖｇ is 0.00 ≤ y ａｖｇ ≤ 0.05, mean value of z ａｖｇ is 0.00 ≤ z ａｖｇ ≤ 0.10, mean value of s ａｖｇ is 0.05 ≤ s ａｖｇ ≤ 0.30, x ａｖｇ ≥ 2 × z ａｖｇ The laminate has a composition represented by (satisfying each of the following conditions), the upper layer has an average thickness of 0.3 to 6.0 μm, and is composed of alternating α sublayers and β sublayers with an average thickness of 3 to 20 nm per layer, wherein the α sublayer is composed of Al ｐ Ti １－ｐ N(mean value of p) ａｖｇ 0.30 ≤ p ａｖｇ The β sublayer has a composition that satisfies ≤ 0.60, and the β sublayer is made of Al ｑ Ti １－ｑ―ｍ M3 ｍ N(M3 is at least one element selected from the group Cr, Mo, Ta, B, Si, W, and the mean value of q is q ａｖｇ 0.50 ≤ q ａｖｇ ≤ 0.80, average value of m ａｖｇ 0.01 ≤ m ａｖｇ ≤ 0.20, q ａｖｇ -p ａｖｇ A surface-coated cutting tool characterized by having a composition that satisfies the condition ≥ 0.01.

Images