Coated tool and cutting tool

Abstract

A coated tool according to a non-limiting aspect of the present disclosure includes a substrate and a coating layer positioned on a surface of the substrate. The coating layer has a TiCNO layer and an Al2O3 layer. The Al2O3 layer is positioned in contact with the TiCNO layer at a position farther from the substrate than the TiCNO layer. The TiCNO layer has a plurality of projections projecting toward the Al2O3 layer. In the composition of the protrusions, N is 3-20 at%.

Description

Coated Tool and Cutting Tool

[0004] Cross-Reference to Related Applications

[0001] This application claims the priority of Japanese Patent Application No. 2025-006074 filed on January 16, 2025, and the entire disclosure of the prior application is incorporated herein by reference.

[0002] This disclosure relates to a coated tool and a cutting tool.

[0003] As a coated tool used for a cutting tool or the like, for example, the coated tool described in International Publication No. 2019 / 146784 (Patent Document 1) is known. The coated tool described in Patent Document 1 has a coating layer located on the surface of a substrate, which includes a TiCNO layer and an Al2O3 layer. The Al2O3 layer is located in contact with the TiCNO layer at a position farther from the substrate than the TiCNO layer. Further, the TiCNO layer has protrusions protruding toward the Al2O3 layer.

[0004] A coated tool according to a non-limiting aspect of the present disclosure is a coated tool including a substrate and a coating layer located on the surface of the substrate. The coating layer has a TiCNO layer and an Al2O3 layer. The Al2O3 layer is located in contact with the TiCNO layer at a position farther from the substrate than the TiCNO layer. The TiCNO layer has a plurality of protrusions protruding toward the Al2O3 layer. In the composition of the protrusions, N is 3 to 20 atomic %.

[0005] It is a perspective view showing a coated tool according to a non-limiting aspect of the present disclosure. It is a cross-sectional view orthogonal to the surface of the substrate in the coated tool shown in FIG. 1. It is an enlarged view of the vicinity of the interface between the TiCNO layer and the Al2O3 layer shown in FIG. 2. It is a schematic diagram for explaining the shape of the protrusion shown in FIG. 3. It is a perspective view showing a cutting tool according to a non-limiting aspect of the present disclosure.

[0006] <Coating Tool> A coating tool 1, which is not limited to this disclosure, will be described in detail below with reference to the drawings. However, in the drawings referenced below, for the sake of convenience of explanation, only the main components necessary for describing the embodiment are shown in a simplified manner. Therefore, the coating tool 1 may have any components not shown in the drawings referenced below. Also, the dimensions of the components in each drawing do not faithfully represent the dimensions of the actual components or the dimensional ratios of each component. Note that Figure 4 is also a cross-sectional view perpendicular to the surface of the base body, but the hatching with diagonal lines indicating that it is a cross-section has been omitted to facilitate visual understanding.

[0007] The coating tool 1 may comprise a substrate 3 and a coating layer 7 located on the surface 5 of the substrate 3, as shown in the example shown in Figures 1 and 2. The coating layer 7 may have a TiCNO layer 9 and an Al2O3 layer 11.

[0008] The TiCNO layer 9 may also be called the titanium carbonate nitride layer. The TiCNO layer 9 contains Ti (titanium), C (carbon), N (nitrogen), and O (oxygen). The TiCNO layer 9 may further contain Al (aluminum). The TiCNO layer 9 may contain other trace components.

[0009] The Al2O3 layer 11 may also be called an alumina layer. The Al2O3 layer 11 may be located in contact with the TiCNO layer 9 at a position further from the substrate 3 than the TiCNO layer 9, as shown in one example (not limited to) in Figure 2.

[0010] The TiCNO layer 9 may have a plurality of protrusions 13 projecting toward the Al2O3 layer 11, as shown in the example (not limited to) in Figure 3. The protrusions 13 may project in a direction perpendicular to the surface 5 of the substrate 3, or in a direction inclined with respect to the surface 5 of the substrate 3. The protrusions 13 may be in contact with the Al2O3 layer 11.

[0011] Here, in the composition of the protrusions 13, the amount of N may be 3 to 20 atomic percent. When the amount of N in the composition of the protrusions 13 is high, the strength of TiCNO (titanium carbonate nitride) tends to improve. Therefore, the anchoring effect of the protrusions 13 is easily obtained, and the Al2O3 layer 11 is less likely to peel off from the TiCNO layer 9. Consequently, the coated tool 1 has high resistance to chipping and fracture. From the viewpoint of improving resistance to chipping and fracture, in the composition of the protrusions 13, the amount of N may be 6 to 19 atomic percent, or 12 to 19 atomic percent.

[0012] In the composition of the protrusion 13, the amount of Ti may be 30 to 50 atomic percent. When the amount of Ti in the composition of the protrusion 13 is low, the adhesion with Al2O3 (alumina) tends to increase. Therefore, the chipping resistance and chipping resistance tend to improve further. From the viewpoint of improving chipping resistance and chipping resistance, the amount of Ti in the composition of the protrusion 13 may be 41 to 47 atomic percent, or 41 to 44 atomic percent.

[0013] Furthermore, in the composition of the protrusion 13, the content ratio of Ti may be the highest. Also, in the composition of the protrusion 13, C may be 10 to 50 atomic percent. In the composition of the protrusion 13, O may be 5 to 25 atomic percent.

[0014] The composition of the projection 13 may be measured, for example, by energy dispersive X-ray spectroscopy (EDS). The measurement may also be performed by cross-sectional observation using an EDS attached to a transmission electron microscope (TEM). Specific measurement conditions may be set as follows, for example: Voltage: 200 kV Beam diameter: approximately 0.4 nmφ Energy resolution: approximately 130 eV X-ray extraction angle: 24.8° Solid angle: approximately 1.1 sr Magnification: 40,000x

[0015] In the shape of the protrusion 13, the average width W of the base 15 may be 0.06 to 0.3 μm, and the average height H may be 0.1 to 0.5 μm (see Figure 4). Protrusions 13 of this shape are wide and low in height, making them less prone to damage. Therefore, the anchoring effect of the protrusion 13 is easily obtained over a long period of time, and the Al2O3 layer 11 is less likely to peel off from the TiCNO layer 9. As a result, fracture resistance and chipping resistance are easily improved. From the viewpoint of improving fracture resistance and chipping resistance, in the shape of the protrusion 13, the average width W of the base 15 may be 0.2 to 0.3 μm, and the average height H may be 0.1 to 0.2 μm.

[0016] The width of the base 15 of the projection 13 is the width of the portion that serves as the starting point for the projection 13. The average width W of the base 15 may be the average value of the widths of the base 15 of 10 or more projections 13. The height of the projection 13 is the length of the line segment connecting the central part 15a of the width of the base 15 and the tip 13a of the projection 13. The average height H of the projection 13 may be the average value of the heights of 10 or more projections 13.

[0017] The base 15 of the projection 13 may be the part of the projection 13 that is closest to the base 3. Also, in a cross-section perpendicular to the surface 5 of the base 3, the projection 13 may be triangular in shape. In this case, the base of the triangular projection 13 may be the base 15 of the projection 13. Also, the tip 13a of the projection 13 may be the part of the projection 13 that is furthest from the base 3. The tip 13a of the projection 13 may be pointed.

[0018] The average width W and average height H may be measured by cross-sectional observation using an electron microscope. This measurement may be performed using the following procedure. First, a cross-section perpendicular to the surface 5 of the substrate 3 is photographed at a magnification of 15,000x using an electron microscope to obtain an electron microscope image. In the obtained electron microscope image, 10 or more protrusions 13 are extracted, and the width of the base 15 and the height of the protrusions 13 are measured, respectively. Then, the average width W and average height H are calculated, respectively. Examples of electron microscopes include scanning electron microscopes (SEM) and TEM. Note that the average width W and average height H do not need to be measured in multiple cross-sections over the entire coating tool 1. The average width W and average height H may be measured in one cross-section at any point on the coating tool 1.

[0019] The Al2O3 layer 11 may have pores 17, as shown in the example (not limited to) in Figure 3. In this case, the stress distribution by the pores 17 makes it easier to mitigate the impact applied to the coating layer 7. Therefore, the fracture resistance and chipping resistance are easily improved.

[0020] In a cross-section perpendicular to the surface 5 of the base body 3, the reference line L may be a line through which the tip 13a of the projection 13 furthest from the base body 3 passes, and which is parallel to the surface 5 of the base body 3 (see Figures 2 and 3).

[0021] The voids 17 may be located on the side of the substrate 3 relative to the reference line L. In this case, the voids 17 are likely to be located in the region where the Al2O3 layer 11 and the protrusions 13 interlock. In this region, the stress distribution effect of the voids 17 is easily obtained. Therefore, in combination with the anchoring effect of the protrusions 13, the Al2O3 layer 11 is less likely to peel off from the TiCNO layer 9. As a result, fracture resistance and chipping resistance are easily improved.

[0022] The Al2O3 layer 11 may have multiple voids 17. In this case, the chipping resistance and fracture resistance are more easily improved.

[0023] In the Al2O3 layer 11, the average diameter of the pores 17 may be 0.01 to 0.35 μm, or 0.01 to 0.15 μm. In this case, the stress distribution effect of the pores 17 can be easily obtained while maintaining the strength of the Al2O3 layer 11.

[0024] The average diameter of the voids 17 may be measured by image analysis. In that case, the equivalent circle diameter may be used as the average diameter of the voids 17. The average diameter of the voids 17 may also be measured by the following procedure. First, a cross-section perpendicular to the surface 5 of the substrate 3 is photographed at a magnification of 15,000 times or more using an electron microscope to obtain an electron microscope image. From the obtained electron microscope image, five or more voids 17 are extracted. Then, the average diameter of the voids 17 is determined by calculating the equivalent circle diameter using the image analysis software ImageJ (1.52).

[0025] The number of protrusions 13 and voids 17 may also be measured by cross-sectional observation using an electron microscope. This measurement may be performed using the following procedure. First, a cross-section perpendicular to the surface 5 of the substrate 3 is photographed at a magnification of 15,000x using an electron microscope to obtain an electron microscope image. A field of view of 18.6 μm × 6 μm of the obtained electron microscope image is defined as one field of view. Then, the number of protrusions 13 and voids 17 present in this field of view is measured.

[0026] In the electron microscope image shown above, "18.6 μm" is the dimension along the surface 5 of the substrate 3, and "6 μm" is the dimension perpendicular to the surface 5 of the substrate 3. Furthermore, the number of protrusions 13 and voids 17 does not need to be measured in multiple cross-sections throughout the entire coating tool 1. The number of protrusions 13 and voids 17 can be measured in one cross-section at any point on the coating tool 1. This also applies when measuring the average diameter of the voids 17.

[0027] The number of protrusions 13 may be 5 to 10 per 1 μm width of the TiCNO layer 9. That is, the number of protrusions 13 may be 5 to 10 per μm. In this case, the anchoring effect of the protrusions 13 is easily obtained, and the Al2O3 layer 11 is less likely to peel off from the TiCNO layer 9. If the number of protrusions 13 is too small, the anchoring effect of the protrusions 13 is difficult to obtain, and if the number of protrusions 13 is too large, they are more likely to become the starting point for fracture, making it difficult to obtain sufficient chipping resistance.

[0028] The number of pores 17 may be 0.4 to 0.8 per 1 μm width of the Al2O3 layer 11. That is, in the Al2O3 layer 11, the number of pores 17 may be 0.4 to 0.8 per μm. In this case, the stress distribution effect due to the pores 17 can be easily obtained while maintaining the strength of the Al2O3 layer 11. When the pores 17 are located on the substrate 3 side of the reference line L, and the number of pores 17 is as described above, it is easy to maintain the strength of the region where the Al2O3 layer 11 and the protrusions 13 interlock.

[0029] In the Al2O3 layer 11, located 0.1 μm away from the TiCNO layer 9, 0.5 atomic percent or more of nitrogen may be present. In this case, the adhesion between TiCNO and Al2O3 is further enhanced. Therefore, chipping resistance and fracture resistance are more easily improved.

[0030] If the Al2O3 layer 11, located 0.1 μm from the TiCNO layer 9, contains 3 atomic percent or more of nitrogen, the chipping resistance and fracture resistance tend to be improved. However, the upper limit of the amount of nitrogen in the Al2O3 layer 11 may be 4 atomic percent or less. The amount of nitrogen in the Al2O3 layer 11 may also be determined by cross-sectional observation using an EDS attached to the TEM. The specific measurement conditions may be the same as those for the composition of the protrusions 13. When measuring the "0.1 μm distance" mentioned above, the surface of the TiCNO layer 9, excluding the protrusions 13, is used as the reference.

[0031] In the Al2O3 layer 11 located 0.1 μm away from the TiCNO layer 9, if N is present in a quantity of 0.5 atomic percent or more, the average height H of the protrusions 13 may be 0.1 to 0.5 μm, or 0.1 to 0.2 μm. In this case, since the protrusions 13 are located in the region of the Al2O3 layer 11 where N is present in a quantity of 0.5 atomic percent or more, the chipping resistance and fracture resistance are more easily improved in combination with the anchoring effect of the protrusions 13.

[0032] The coating layer 7 may have, in order from the substrate 3, a first TiCN layer 19, a second TiCN layer 21, a TiCN Oxide layer 9, and an Al2O3 layer 11, as shown in the example not limited to Figure 2. In this case, the lifespan of the coating tool 1 tends to be longer.

[0033] The first TiCN layer 19 may be a so-called MT (moderate temperature)-TiCN layer. The second TiCN layer 21 may be a so-called HT (high temperature)-TiCN layer.

[0034] The coating layer 7 is not limited to a specific thickness. For example, the TiCNO layer 9 may have an average thickness of 100 to 1500 nm. In this case, the hardness of the TiCNO layer 9 is less likely to decrease, and the Al2O3 layer 11 is more likely to form an α-type crystal structure. The thickness of the TiCNO layer 9 is the value excluding the protrusions 13.

[0035] The Al2O3 layer 11 may have an average thickness of 1 to 15 μm. The average thickness of the Al2O3 layer 11 may be greater than the average thickness of the TiCNO layer 9.

[0036] The first TiCN layer 19 may have an average thickness of 2 to 15 μm. The second TiCN layer 21 may have an average thickness of 10 to 900 nm.

[0037] The average thickness of the coating layer 7 may be measured by cross-sectional observation using an electron microscope. For example, the thickness may be measured at 10 or more measurement points at arbitrary positions in each layer, and the average value may be calculated.

[0038] The coating layer 7 may be located over the entire surface 5 of the substrate 3, or may be located only on a part thereof. That is, the coating layer 7 may be located on at least a part of the surface 5 of the substrate 3.

[0039] The coating layer 7 may be formed by a chemical vapor deposition (CVD) method. In other words, the coating layer 7 may be a CVD film. Note that the coating layer 7 may be a PVD film formed by a physical vapor deposition (PVD) method.

[0040] Examples of the material of the substrate 3 may include cemented carbide, ceramics, and metals. Examples of the cemented carbide may include a carbide alloy containing WC (tungsten carbide) and a ferrous metal such as Co (cobalt) or Ni (nickel). Examples of other cemented carbides may include a Ti-based cermet containing TiCN (titanium carbonitride) and a ferrous metal. Examples of the ceramics may include Si3N4 (silicon nitride), Al2O3, diamond, and cBN (cubic boron nitride). Examples of the metals may include carbon steel, high-speed steel, and alloy steel.

[0041] In FIG. 1, a cutting insert is shown as a non-limiting example of the coated tool 1. Note that the form of the coated tool 1 is not limited to the cutting insert.

[0042] The coated tool 1 may have a first surface 23 (upper surface), a second surface 25 (side surface) adjacent to the first surface 23, and a cutting edge 27 located at the intersection of the first surface 23 and the second surface 25.

[0043] The first surface 23 may be a rake face. The entire first surface 23 may be a rake face, or only a part thereof may be a rake face. For example, the region along the cutting edge 27 of the first surface 23 may be a rake face.

[0044] The second surface 25 may be a flank face. The entire second surface 25 may be a flank face, or only a part thereof may be a flank face. For example, the region along the cutting edge 27 of the second surface 25 may be a flank face.

[0045] The cutting edge 27 may be located at the entire intersection of the first surface 23 and the second surface 25, or may be located only at a part of this intersection. The cutting edge 27 can be used to cut a workpiece when manufacturing a machined product using the coated tool 1.

[0046] The coated tool 1 may have a through-hole 29. The through-hole 29 can be used to attach a screw or a clamping member or the like when fixing the coated tool 1 to a holder. The through-hole 29 may be formed from the first surface 23 to the surface (lower surface) located on the opposite side of the first surface 23, and may also open on these surfaces. Incidentally, there is no problem even if the through-hole 29 is configured to open in the regions facing each other on the second surface 25.

[0047] The coated tool 1 may be in the shape of a square plate. Note that the shape of the coated tool 1 is not limited to the square plate shape. For example, the first surface 23 may be triangular, pentagonal, hexagonal, or circular.

[0048] The coated tool 1 is not limited to a specific size. For example, the length of one side of the first surface 23 may be set to about 3 to 20 mm. Also, the height from the first surface 23 to the surface (lower surface) located on the opposite side of the first surface 23 may be set to about 5 to 20 mm.

[0049] <Manufacturing method of coated tool> Next, a manufacturing method of the coated tool on one aspect of the present disclosure that is not limited will be described.

[0050] When manufacturing the coated tool, a substrate may be first produced. The case of producing a substrate made of cemented carbide will be described as an example. First, inorganic powder such as carbide, nitride, carbonitride, oxide, etc. that can form a substrate by firing may be appropriately added with metal powder, carbon powder, etc. and mixed to obtain a mixed powder. Next, using this mixed powder, it may be formed into a predetermined tool shape by a known forming method such as press molding, casting molding, extrusion molding, cold isostatic press molding. Then, by firing the obtained formed body in a vacuum or a non-oxidizing atmosphere, a substrate made of cemented carbide may be obtained. The surface of the obtained substrate may be subjected to polishing or honing.

[0051] Next, a coating layer may be formed on the surface of the obtained substrate by CVD to obtain a coated tool. As an example, the deposition conditions for each layer will be explained in order, taking as an example the case in which the coating layer has, in order from the substrate, a first TiCN layer (MT-TiCN layer), a second TiCN layer (HT-TiCN layer), a TiCNO layer, and an Al2O3 layer.

[0052] The first TiCN layer (MT-TiCN layer) may be formed as follows. First, a mixed gas may be prepared as the reaction gas composition, consisting of 0.5 to 10 volume% titanium tetrachloride (TiCl4) gas, 5 to 60 volume% nitrogen (N2) gas, 0.1 to 3 volume% acetonitrile (CH3CN) gas, and the remainder being hydrogen (H2) gas. Then, this mixed gas may be introduced into the chamber, the deposition temperature may be set to a relatively low temperature of 780 to 880°C, and the pressure may be set to 5 to 25 kPa to form the first TiCN layer.

[0053] The second TiCN layer (HT-TiCN layer) may be deposited as follows. First, a mixed gas may be prepared as the reaction gas composition, consisting of 1 to 4 volume% titanium tetrachloride (TiCl4) gas, 5 to 20 volume% nitrogen (N2) gas, 0.1 to 10 volume% methane (CH4) gas, and the remainder being hydrogen (H2) gas. Then, this mixed gas may be introduced into the chamber, and the deposition temperature may be set to 900 to 990°C and the pressure to 5 to 40 kPa to deposit the second TiCN layer. The second TiCN layer may be deposited at a higher temperature than the first TiCN layer.

[0054] The TiCNO layer may be formed as follows. First, a mixed gas may be prepared as the reaction gas composition, consisting of 2 to 15 volume% titanium tetrachloride (TiCl4) gas, 15 to 45 volume% nitrogen (N2) gas, 5 to 9 volume% methane (CH4) gas, 0.5 to 10 volume% carbon monoxide (CO) gas, and the remainder being hydrogen (H2) gas. Then, this mixed gas may be introduced into a chamber, and the TiCNO layer may be formed by setting the deposition temperature to 900 to 990°C and the pressure to 5 to 40 kPa. When the deposition temperature of the TiCNO layer is low, the amount of N in the TiCNO layer tends to be high. At the same time, the protrusions tend to become thinner.

[0055] When a TiCNO layer is deposited under the above-described deposition conditions, protrusions having the above-described structure are likely to form. Furthermore, when the deposition temperature is set to 945-955°C, when an Al2O3 layer is deposited on top of the TiCNO layer, the Al2O3 layer located 0.1 μm away from the TiCNO layer tends to contain 0.5 atomic percent or more of nitrogen. In addition, when an Al2O3 layer is deposited on top of the TiCNO layer, vacancies having the above-described structure are likely to form in the Al2O3 layer. The reason why vacancies are likely to form in the Al2O3 layer is thought to be that the deposition rate tends to be high, and the formation of alumina is locally suppressed due to the high nitrogen content of the TiCNO and the resulting protrusion shape of the TiCNO.

[0056] The Al2O3 layer may be formed as follows. First, a mixed gas may be prepared as the reaction gas composition, consisting of 3.5 to 15 volume% aluminum trichloride (AlCl3) gas, 0.5 to 2.5 volume% hydrogen chloride (HCl) gas, 0.5 to 5 volume% carbon dioxide (CO2) gas, 0 to 1 volume% hydrogen sulfide (H2S) gas, and the remainder being hydrogen (H2) gas. Then, this mixed gas may be introduced into a chamber, the film deposition temperature may be set to 900 to 990°C and the pressure to 5 to 20 kPa, and the Al2O3 layer may be deposited.

[0057] In the resulting coated tool, at least the portion of the surface of the coating layer where the cutting edge is located may be polished. In this case, the cutting edge tends to become smoother. Therefore, the workpiece is less likely to weld to the tool, and the coated tool tends to have higher resistance to chipping and fracture.

[0058] It should be noted that the above manufacturing method is just one example of a method for manufacturing coated tools. Therefore, it goes without saying that coated tools are not limited to those manufactured by the above manufacturing method.

[0059] <Cutting Tools> Next, a cutting tool 101, not limited to this disclosure, will be described with reference to the drawings, using the case in which the above-described coated tool 1 is provided as an example.

[0060] The cutting tool 101 may include a holder 103 and a coated tool 1, as shown in the example not limited to Figure 5. The holder 103 may extend from a first end 103a toward a second end 103b, and may have a pocket 105 on the side of the first end 103a. The coated tool 1 may be located in the pocket 105. When the cutting tool 101 includes a coated tool 1, the high resistance to chipping and fracture of the coated tool 1 makes it easier to improve cutting performance such as intermittent performance, enabling stable cutting.

[0061] The pocket 105 may be the portion into which the covering tool 1 is attached. The pocket 105 may be open on the outer circumferential surface of the holder 103 and on the end face on the side of the first end 103a.

[0062] The covering tool 1 may be mounted in the pocket 105 such that at least a portion of the cutting edge 27 protrudes from the holder 103. Alternatively, the covering tool 1 may be mounted in the pocket 105 by a screw 107. That is, the covering tool 1 may be mounted in the pocket 105 by inserting the screw 107 into the through hole 29 of the covering tool 1, and then inserting the tip of the screw 107 into a screw hole formed in the pocket 105 and fixing the screw 107 in the screw hole. In this case, the lower surface of the covering tool 1 may be in direct contact with the pocket 105, or a sheet may be sandwiched between the covering tool 1 and the pocket 105.

[0063] Examples of materials for the holder 103 include steel and cast iron. When the holder 103 is made of steel, it has high toughness.

[0064] In the example shown in Figure 5, a cutting tool 101 used in so-called turning operations is illustrated. Examples of turning operations include internal diameter machining, external diameter machining, and grooving operations. Note that the cutting tool 101 (coated tool 1) is not limited to turning operations. For example, there is no problem in using the coated tool 1 as a cutting tool 101 used in milling operations.

[0065] The above exemplifies one aspect of the coating tool 1 and cutting tool 101 that are not limited to the present disclosure. However, it goes without saying that the present disclosure is not limited to the above embodiments and can be any as long as it does not deviate from the gist of the present disclosure.

[0066] For example, the coated tool 1 and the cutting tool 101 may have the following configurations: [1] The coated tool is a coated tool comprising a substrate and a coating layer located on the surface of the substrate, wherein the coating layer has a TiCNO layer and an Al2O3 layer, the Al2O3 layer is located in contact with the TiCNO layer at a position further from the substrate than the TiCNO layer, the TiCNO layer has a plurality of protrusions projecting toward the Al2O3 layer, and in the composition of the protrusions, N is 3 to 20 atomic percent. [2] In the coated tool of [1] above, Ti may be 30 to 50 atomic percent in the composition of the protrusions. [3] In the coated tool of [1] or [2] above, the average width of the base of the protrusions may be 0.06 to 0.3 μm and the average height may be 0.1 to 0.5 μm. [4] In any one of the coated tools of [1] to [3] above, the Al2O3 layer may have pores. [5] In the coating tool described in [4] above, in a cross section perpendicular to the surface of the substrate, a line parallel to the surface of the substrate and passing through the tip of the projection furthest from the substrate among the plurality of projections is a reference line, and the voids may be located on the substrate side of the reference line. [6] In any one of the coating tools described in [3] to [5] above, the number of projections may be 5 to 10 per μm. [7] In any one of the coating tools described in [4] to [6] above, the average diameter of the voids in the Al2O3 layer may be 0.01 to 0.35 μm. [8] In the coating tool described in [7] above, the number of voids in the Al2O3 layer may be 0.4 to 0.8 per μm. [9] In any one of the coating tools described in [1] to [8] above, the Al2O3 layer located 0.1 μm away from the TiCNO layer may contain 0.5 atomic percent or more of N.

[10] Any one of the coating tools described in [1] to [9] above may have a coating layer having, in order from the substrate, a first TiCN layer, a second TiCN layer, the TiCNO layer and the Al2O3 layer.

[11] A cutting tool may comprise a holder extending from a first end toward a second end and having a pocket on the side of the first end, and any one of the coating tools described in [1] to

[10] above located in the pocket.

[0067] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to the following examples.

[0068] [Sample No. 1-8] <Preparation of coated tools> First, the substrate was prepared. Specifically, a mixed powder was obtained by mixing 6% by mass of metallic cobalt powder with an average particle size of 1.2 μm, 0.5% by mass of titanium carbide powder with an average particle size of 2 μm, 5% by mass of niobium carbide powder with an average particle size of 2 μm, and the remainder being tungsten carbide powder with an average particle size of 1.5 μm. The average particle size of each powder was measured using the microtrac method.

[0069] Next, the obtained mixed powder was press-molded into a tool shape (CNMG120408) to obtain a molded body. The obtained molded body was then subjected to a binder removal treatment and fired in a non-oxidizing atmosphere to obtain a substrate made of cemented carbide. The firing temperature was set to 1450°C and the firing time to 1 hour, and an argon atmosphere was used as the non-oxidizing atmosphere. The obtained substrate was then brush-finished, and R-honing was applied to the cutting edge portion.

[0070] Next, a coating layer was deposited on the surface of the obtained substrate by CVD to obtain coated tools of the samples shown in Table 1. The samples shown in Table 1 have the following layers deposited in order from the substrate: a first TiCN layer (MT-TiCN layer), a second TiCN layer (HT-TiCN layer), a TiCNO layer, and an Al2O3 layer. The deposition conditions for each layer are as follows.

[0071] (Conditions for deposition of the first TiCN layer (MT-TiCN layer)) First, a mixed gas was prepared as the reaction gas composition, consisting of 4 vol% titanium tetrachloride (TiCl4) gas, 23 vol% nitrogen (N2) gas, 0.4 vol% acetonitrile (CH3CN) gas, and the remainder being hydrogen (H2) gas. This mixed gas was then introduced into the chamber, and the deposition temperature was set to 850°C and the pressure to 9 kPa. The deposition time was set to 400 minutes.

[0072] (Conditions for deposition of the second TiCN layer (HT-TiCN layer)) First, a mixed gas was prepared as the reaction gas composition, consisting of 4 vol% titanium tetrachloride (TiCl4) gas, 20 vol% nitrogen (N2) gas, 8 vol% methane (CH4) gas, and the remainder being hydrogen (H2) gas. This mixed gas was then introduced into the chamber, and the deposition temperature was set to 950°C and the pressure to 13 kPa. The deposition time was set to 80 minutes.

[0073] (Conditions for depositing the TiCNO layer) First, a mixed gas with the reaction gas composition shown in Table 1 was prepared. Then, this mixed gas was introduced into the chamber, the deposition temperature was set to the temperature shown in Table 1, and the pressure was set to 10 kPa. The deposition time was set to 60 minutes.

[0074] (Conditions for depositing the Al2O3 layer) First, a mixed gas was prepared as the reaction gas composition, consisting of 3.7 volume% aluminum trichloride (AlCl3) gas, 0.7 volume% hydrogen chloride (HCl) gas, 4.3 volume% carbon dioxide (CO2) gas, 0.3 volume% hydrogen sulfide (H2S) gas, and the remainder being hydrogen (H2) gas. This mixed gas was then introduced into the chamber, and the deposition temperature was set to 950°C and the pressure to 7.5 kPa. The deposition time was set to 380 minutes.

[0075] The composition of the protrusions of the obtained coated tools was measured according to the method exemplified above. Specifically, the composition of the protrusions was measured by cross-sectional observation using the EDS attached to the TEM. The measurement conditions were set as exemplified above. The measurement was performed on one cross-section of the rake face. The measurement results are shown in the "Composition (atomic %)" column under "Protrusions" in Table 1.

[0076] Furthermore, regarding the shape of the protrusions, the average width of the base of the protrusions and the average height of the protrusions were measured according to the method exemplified above. That is, the shape of the protrusions was measured by cross-sectional observation using an electron microscope according to the procedure described above. The measurement was performed on one cross-section of the rake face, and the number of measurements was 10. A scanning electron microscope (SEM) was used. The measurement results are shown in Table 1. The average width of the base is shown in the "Average Width" column under "Shape (μm)" in Table 1.

[0077] The number of protrusions was measured according to the method exemplified above. Specifically, the number of protrusions was measured by cross-sectional observation using an electron microscope according to the procedure described above. The measurement was performed on one cross-section of the rake face. A scanning electron microscope (SEM) was used. The measurement results are shown in the "Number (pieces / μm)" column under "Protrusions" in Table 1.

[0078] The presence or absence of voids in the Al2O3 layer of the obtained coated tools was confirmed by cross-sectional observation using a scanning electron microscope (SEM). The results are shown in the "Presence or Absence" column under "Vacancies" in Table 1.

[0079] The average diameter of the voids was measured according to the method exemplified above. That is, the average diameter of the voids was measured by image analysis according to the procedure described above. The measurement was performed on one cross-section of the scoop face. An electron microscope (SEM) was used, with a magnification of 15,000x, and five voids were extracted. The measurement results are shown in the "Average Diameter (μm)" column under "Voids" in Table 1.

[0080] The number of voids was measured according to the method exemplified above. Specifically, the number of voids was measured by cross-sectional observation using an electron microscope, following the procedure described above. The measurement was performed on one cross-section of the scoop face. A scanning electron microscope (SEM) was used. The measurement results are shown in the "Number (voids / μm)" column under "Vacancies" in Table 1.

[0081] The amount of nitrogen (N) in the Al2O3 layer, located 0.1 μm away from the TiCNO layer, was measured. The measurement was performed under the same conditions as the composition of the protrusions. The measurement results are shown in the "Amount of N in the Al2O3 layer (atomic %)" column of Table 1.

[0082] <Evaluation> The obtained coated tool was subjected to a cutting test under the following conditions: Machining method: Turning Cutting speed: 120 m / min Feed rate: 0.2 mm / rev Depth of cut: 1.5 mm Workpiece material: Ductile cast iron 8-groove sleeve material (FCD700) Machining condition: Wet

[0083] The evaluation results are shown in the "Number of Impacts Until Cutting Edge Breakage" column of Table 1. Note that "Number of Impacts Until Cutting Edge Breakage" represents the number of impacts required for the cutting edge to break during machining, and can also be called intermittent performance evaluation.

[0084]

[0085] Samples No. 1-4, 6, and 7 showed high resistance to chipping and fracture, with a high number of impacts before the cutting edge broke. Furthermore, the voids in samples No. 1-4 and 7 were located closer to the substrate than the aforementioned reference line.

[0086] 1...Coating tool 3...Substrate 5...Surface 7...Coating layer 9...TiCNO layer 11...Al2O3 layer 13...Protrusion 13a...Tip 15...Base 15a...Center 17...Vacuum 19...First TiCN layer 21...Second TiCN layer 23...First surface (top surface) 25...Second surface (side surface) 27...Cutting edge 29...Through hole 101...Cutting tool 103...Holder 103a...First end 103b...Second end 105...Pocket 107...Screw W...Average width H...Average height L...Reference line

Claims

1. A coating tool comprising a substrate and a coating layer located on the surface of the substrate, wherein the coating layer comprises a TiCNO layer and an Al2O3 layer, the Al2O3 layer is located in contact with the TiCNO layer at a position further from the substrate than the TiCNO layer, the TiCNO layer has a plurality of protrusions projecting toward the Al2O3 layer, and the composition of the protrusions is such that N is 3 to 20 atomic percent.

2. The coating tool according to claim 1, wherein the composition of the protrusions contains 30 to 50 atomic percent Ti.

3. The coating tool according to claim 1 or 2, wherein the shape of the projection has an average width of 0.06 to 0.3 μm at its base and an average height of 0.1 to 0.5 μm.

4. The coating tool according to any one of claims 1 to 3, wherein the Al2O3 layer has pores.

5. The coating tool according to claim 4, wherein, in a cross section perpendicular to the surface of the substrate, a line parallel to the surface of the substrate and passing through the tip of the projection furthest from the substrate among the plurality of projections is a reference line, and the void is located on the substrate side of the reference line.

6. The coating tool according to any one of claims 3 to 5, wherein the number of protrusions is 5 to 10 per μm.

7. The coating tool according to any one of claims 4 to 6, wherein the average diameter of the pores in the Al2O3 layer is 0.01 to 0.35 μm.

8. The coating tool according to claim 7, wherein the number of pores in the Al2O3 layer is 0.4 to 0.8 pores / μm.

9. The coating tool according to any one of claims 1 to 8, wherein the Al2O3 layer, located at a distance of 0.1 μm from the TiCNO layer, contains 0.5 atomic percent or more of N.

10. The coating tool according to any one of claims 1 to 9, wherein the coating layer comprises, in order from the substrate, a first TiCN layer, a second TiCN layer, the TiCNO layer, and the Al2O3 layer.

11. A cutting tool comprising: a holder extending from a first end toward a second end and having a pocket on the side of the first end; and a covering tool according to any one of claims 1 to 10, positioned in the pocket.

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