WO2024095655A1 - Coated tool and cutting tool - Google Patents

Abstract

A coated tool according to a non-limiting aspect of the present disclosure comprises 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 composite protrusions including first protrusions that protrude toward the Al₂O₃ layer and second protrusions that protrude from the first protrusions in a direction that intersects the protrusion direction of the first protrusions. In a cross section intersecting the surface of the substrate, an average width A of the base portions of the first protrusions is 200 to 1200 nm, and an average length B of the first protrusions is 200 to 1000 nm. A cutting tool according to a non-limiting aspect of the present disclosure comprises a holder that extends from a first end toward a second end and has a pocket on the first end side, and the coated tool that is positioned in the pocket.

Description

Coated and cutting tools CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2022-177110, filed November 4, 2022, the entire disclosure of which is incorporated herein by reference.

This disclosure relates to coated tools and cutting tools.

Coated tools are known in which an _Al2O3 layer or _the like is laminated via a bonding film on the surface of a substrate such as cemented carbide, cermet, or ceramics. Coated tools in which a coating layer is formed on the surface of a substrate are used as cutting tools, etc.

As cutting processes have become more efficient in recent years, cutting tools are increasingly being used for heavy intermittent cutting, where the cutting edge is subjected to large impacts. Under such harsh cutting conditions, the coating layer is subjected to large impacts, making it prone to chipping and peeling. For this reason, the coating layer is required to have improved chipping resistance in addition to wear resistance.

As a technique for improving the chipping resistance of cutting tools, Japanese Patent No. 5303732 (Patent Document 1) discloses that a bonding film and _{an Al2O3} layer are sequentially formed, and dendrites extending toward _{the Al2O3} layer and branch-like protrusions connected to the dendrites are provided on the bonding film, thereby increasing the adhesion between the bonding film and _{the Al2O3} layer and suppressing peeling of the coating layer. Patent Document 1 discloses that the dendrites are Ti(CO) or Ti(CNO), and the branch-like protrusions are (TiAl)(CNO), and describes that after the dendrites are formed, the flow of the raw material gas is stopped once, and the pressure and the type of raw material gas are changed while maintaining the temperature to form branch-like protrusions having a composition different from that of the dendrites.

A non-limiting coated tool 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 includes a TiCNO layer and an Al ₂ O ₃ layer. The Al ₂ O ₃ 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 composite projections including first projections projecting toward the Al ₂ O ₃ layer and second projections projecting from the first projections in a direction intersecting the direction in which the first projections project. In a cross section perpendicular to the surface of the substrate, A, which is the average width of the base of the first projections, is 200 to 1200 nm, and B, which is the average length of the first projections, is 200 to 1000 nm.

The non-limiting one-sided cutting tool of the present disclosure includes a holder extending from a first end to a second end and having a pocket on the first end side, and the coated tool described above positioned in the pocket.

FIG. 1 is a perspective view of a non-limiting one-sided coated tool of the present disclosure. 2 is a cross-sectional view perpendicular to the surface of the substrate in the coated tool shown in FIG. 1 . 3 is an enlarged view of the vicinity of the boundary between the TiCNO layer and the Al ₂ O ₃ layer shown in FIG. 2. 2 is a schematic diagram for explaining primary projections A and B in the coated tool shown in FIG. 1 . FIG. 2 is a schematic diagram for explaining secondary projections C and D in the coated tool shown in FIG. 1 . FIG. 2 is a schematic diagram for explaining secondary projections C and D in the coated tool shown in FIG. 1 . FIG. FIG. 4 is a cross-sectional view of a non-limiting one-sided coated tool of the present disclosure, corresponding to FIG. 3; FIG. 1 is a perspective view of a non-limiting one-sided cutting tool of the present disclosure.

<Coated tools>
Hereinafter, the coated tool 1 of one side of the present disclosure will be described in detail with reference to the drawings. However, in each of the drawings referred to below, for convenience of explanation, only the main members necessary for explaining the embodiment are shown in a simplified manner. Therefore, the coated tool 1 may include any component members not shown in each of the drawings referred to. In addition, the dimensions of the components in each drawing do not faithfully represent the dimensions of the actual components and the dimensional ratios of each component. Note that although Figs. 4 to 6 are also cross-sectional views perpendicular to the surface of the base body, the hatching with diagonal lines indicating that it is a cross section has been omitted to facilitate visual understanding.

1 and 2, the coated tool 1 may include a substrate 3 and a coating layer 7 located on a surface 5 of the substrate 3. The coating layer 7 may include a TiCNO layer 9 (titanium carbonate nitride layer) and an _Al2O3 layer 11 (alumina layer). _{The Al2O3} layer 11 may be located in contact with the TiCNO layer 9 at a position farther from the substrate 3 than _the TiCNO layer 9.

The TiCNO layer 9 may have a plurality of composite protrusions 13, as in a non-limiting example shown in Fig. 3. Each of the plurality of composite protrusions 13 may have a first protrusion 15 protruding toward _{the Al2O3} layer 11, and a second protrusion 17 protruding from the first protrusion 15 in a direction intersecting with the protruding direction of the first protrusion 15. In this case, due to the interlocking between the composite protrusions 13 and the _Al2O3 layer ₁₁ , the TiCNO layer 9 and _{the Al2O3} layer 11 are unlikely to peel off from each other.

Here, as a non-limiting example shown in Figures 3 and 4, in a cross section perpendicular to the surface 5 of the substrate 3, A, which is the average width of the base 19 of the first protrusions 15, may be 200 to 1200 nm, and B, which is the average length of the first protrusions 15, may be 200 to 1000 nm.

The first projections 15 having A and B have a relatively large overall size because both A and B are relatively large. The _Al2O3 layer 11 located in contact with the TiCNO layer 9 in which such first projections 15 exist has a high texture coefficient Tc(006) and is likely to have a high degree of orientation. The effect of the _Al2O3 layer ₁₁ being likely to have a high degree of orientation, combined with the effect of the meshing between the composite projections ₁₃ and the _Al2O3 layer 11 _, tends to improve chipping resistance and wear resistance. Therefore, the coated tool 1 has high wear resistance and chipping resistance.

Note that A may be 400 nm or more. A may be 1000 nm or less. B may be 400 nm or more. B may be 800 nm or less.

The width of the base 19 of the first protrusion 15 may be the width of the portion that is the starting point of the protrusion of the first protrusion 15. The average width A of the base 19 of the first protrusion 15 may be the average value of the width of the base 19 of 10 or more first protrusions 15. The length of the first protrusion 15 may be the length of the line segment connecting the central portion 19a of the width of the portion (base 19) that is the starting point of the protrusion of the first protrusion 15 and the tip 15a of the first protrusion 15. The average length B of the first protrusion 15 may be the average value of the lengths of 10 or more first protrusions 15.

The base 19 of the first protrusion 15 may be the part of the first protrusion 15 that is located closest to the base 3. Also, in a cross section perpendicular to the surface 5 of the base 3, the first protrusion 15 may be triangular. In this case, the base of the triangular first protrusion 15 may be the base 19 of the first protrusion 15. Also, the tip 15a of the first protrusion 15 may be the part of the first protrusion 15 that is located farthest from the base 3. The tip 15a of the first protrusion 15 may be pointed.

A and B may be measured by cross-sectional observation using an electron microscope. A cross section perpendicular to the surface 5 of the substrate 3 may be photographed using an electron microscope at a magnification of 15,000 times, and 10 or more composite protrusions 13 may be extracted from the resulting electron microscope photograph to measure A and B. Examples of electron microscopes include a scanning electron microscope (SEM) and a transmission electron microscope (TEM). It is not necessary to measure A and B at multiple cross sections throughout the entire coated tool 1. A and B may be measured at one cross section at any point on the coated tool 1. The same applies to C and D described below.

The relationship between A and B may satisfy (A/B)>1. In this case, A, which is the average width of the base 19 of the first protrusion 15, becomes relatively large, making it easier to ensure the strength of the first protrusion 15, which has a relatively large overall size. Therefore, the first protrusion 15 is less likely to break.

At least one of the multiple composite protrusions 13 may have multiple second protrusions 17. In this case, the TiCNO layer 9 and _{the Al2O3} layer 11 are even less likely to peel off. All of the multiple composite protrusions 13 may have multiple second protrusions 17. The composite protrusion 13 having multiple second protrusions 17 means that multiple second protrusions 17 are located on one first protrusion 15.

3 and 5, in a cross section perpendicular to the surface 5 of the substrate 3, the average width C of the base 21 of the secondary projections 17 may be 20 to 150 nm, and the average length D of the secondary projections 17 may be 20 to 150 nm. The secondary projections 17 having such C and D are less likely to crack or break between them and the primary projections 15. Therefore, the TiCNO layer 9 and the Al ₂ O ₃ layer 11 are even less likely to peel off.

Note that C may be 40 nm or more. C may be 125 nm or less. D may be 40 nm or more. D may be 120 nm or less.

The width of the base 21 of the second protrusion 17 may be the width of the portion that is the starting point of the protrusion of the second protrusion 17. The average width C of the base 21 of the second protrusion 17 may be the average value of the width of the base 21 of 10 or more second protrusions 17. The length of the second protrusion 17 may be the length of the line segment connecting the center 21a of the width of the portion (base 21) that is the starting point of the protrusion of the second protrusion 17 and the tip 17a of the second protrusion 17. The average length D of the second protrusion 17 may be the average value of the lengths of 10 or more second protrusions 17. Measurement of C and D may be performed in the same manner as the measurement of A and B using an electron microscope described above.

The base 21 of the second protrusion 17 may be the part of the second protrusion 17 that is located closest to the first protrusion 15. Furthermore, in a cross section perpendicular to the surface 5 of the base 3, the second protrusion 17 may be triangular. In this case, the base of the triangular second protrusion 17 may be the base 21 of the second protrusion 17. Furthermore, the tip 17a of the second protrusion 17 may be the part of the second protrusion 17 that is located farthest from the first protrusion 15. The tip 17a of the second protrusion 17 may be pointed.

In a cross section perpendicular to the surface 5 of the base 3, the second protrusion 17 may have a first side 17b and a second side 17c that extend from two points where the first protrusion 15 and the second protrusion 17 meet toward the tip 17a of the second protrusion 17. As shown in a non-limiting example in FIG. 5, the first side 17b and the second side 17c may be linear.

The first side 17b and the second side 17c do not have to be straight. For example, the first side 17b and the second side 17c may be curved, or may be a combination of straight and curved lines. In a non-limiting example shown in FIG. 6, the first side 17b' and the second side 17c' are curved. When the second protrusion 17' is not a perfect triangle, as in the non-limiting example shown in FIG. 6, the length of the line segment connecting the two points where the first protrusion 15 and the second protrusion 17' meet may be the width of the base 21 of the second protrusion 17'. The length of the line segment connecting the center 21a of the width of the base 21 and the tip 17a of the second protrusion 17' may be the length of the second protrusion 17'.

In addition, in a cross section such as that shown in FIG. 6, when it is difficult to identify the boundary between the first protrusion 15 and the second protrusion 17', such as when the outer edges of the first protrusion 15 and the second protrusion 17' are both shown as curves and these curves are smoothly connected, the boundary between the first protrusion 15 and the second protrusion 17', i.e., the base 21 of the second protrusion 17', may be identified by the following procedure.

For example, if the outer edges of the first protrusion 15 and the second protrusion 17' are both curved, then in the cross section shown in FIG. 6, two curved lines are illustrated from the tip 17a of the second protrusion 17' toward the first protrusion 15. At this time, a tangent line that touches both of these two curved lines is uniquely identified. The two tangent points of these two curved lines and the tangent lines form the boundary between the first protrusion 15 and the second protrusion 17'. In this case, the portion sandwiched between the two tangent points of the above tangent lines corresponds to the base 21.

As described above, when it is difficult to identify the boundary between the first protrusion 15 and the second protrusion 17 in the cross section, it is sufficient to identify the tangent line that touches both of the two outer edges extending from the tip 17a of the second protrusion 17 toward the first protrusion 15. This makes it possible to identify the boundary between the first protrusion 15 and the second protrusion 17, and further to identify the base 21.

In addition, when the outer edge of the first protrusion 15 in the cross section is curved, the width of the base 19 of the first protrusion 15 can be evaluated using the same evaluation method as above. The base 19 of the first protrusion 15 can be identified by identifying the tangents at the two boundaries between the target first protrusion 15 and the two first protrusions 15 adjacent to this first protrusion 15.

The relationship between C and D may be (C/D)>1. In this case, C, which is the average width of the base 21 of the second protrusions 17, becomes relatively large, so that the second protrusions 17 are less likely to have an elongated shape and tend to have a stable shape. Therefore, cracks and breakage are less likely to occur between the first protrusions 15 and the second protrusions 17.

The texture coefficient Tc(006) of the _Al2O3 layer ₁₁ may be 7.5 or more. In this case, chipping resistance and wear resistance are likely to be improved. _{The Al2O3} layer 11 may have an α-type crystal structure.

The texture coefficient Tc(006) may be measured by, for example, X-ray diffraction (XRD) analysis. Specifically, based on the peak of the _Al2O3 layer ₁₁ analyzed by XRD analysis, a value expressed by the following formula may be set as the texture coefficient Tc(hkl). The texture coefficient Tc(006) detected by measurement from the surface side of _{the Al2O3} layer 11 may be 7.5 or more.
Texture coefficient Tc(hkl)={I(hkl)/I ₀ (hkl)}/[(1/9)×Σ{I(HKL)/I ₀ (HKL)}]
Here, (HKL) are the crystal planes (012), (104), (110), (006), (113), (024), (116), (214), and (146).
I(HKL) and I(hkl) are the peak intensities of the peaks assigned to the respective crystal planes detected in the XRD analysis of the Al ₂ O ₃ layer 11 .
I ₀ (HKL) and I ₀ (hkl) are the standard diffraction intensities of each crystal plane described in JCPDS Card No. 00-010-0173.

The TiCNO layer 9 may have other protrusions 23 different from the composite protrusions 13, as in the non-limiting example shown in FIG. 3. In this case, the composite protrusions 13 may account for 60% or more of the total protrusions. In this case, the composite protrusions 13 become the main protrusions. This makes it easier to obtain a coated tool 1 with high wear resistance and chipping resistance.

The upper limit of the ratio of the composite protrusions 13 may be, for example, 70%. Note that the upper limit of the ratio of the composite protrusions 13 is not limited to the exemplified value. For example, there is no problem even if the ratio of the composite protrusions 13 is 100%.

The ratio of composite protrusions 13 is a value calculated from the formula: (number of composite protrusions/total number of protrusions) x 100. The total number of protrusions is the sum of the number of composite protrusions 13 and the number of other protrusions 23. The length of the other protrusions 23, measured in the same manner as the first protrusions 15, may be 200 nm or more.

The total number of protrusions may be measured by cross-sectional observation using an electron microscope. For example, a cross section perpendicular to the surface 5 of the substrate 3 may be photographed at a magnification of 15,000 times using an electron microscope, and the number of composite protrusions 13 and other protrusions 23 present within an area of 18.6 μm × 6 μm in the obtained electron microscope photograph may be measured. The total number of protrusions may be 5 to 20 per field of view in the electron microscope photograph. Furthermore, it is not necessary to measure the total number of protrusions at multiple cross sections throughout the entire coated tool 1. The total number of protrusions may be measured at one cross section at any location on the coated tool 1.

The first protrusions 15 and the second protrusions 17 may contain titanium, carbon, nitrogen and oxygen, or may have the same composition. In this case, cracks and breaks are unlikely to occur between the first protrusions 15 and the second protrusions 17, and the adhesion between the TiCNO layer 9 and the _Al2O3 layer 11 is higher than when the first protrusions 15 and the _second protrusions 17 have different compositions.

Having a homogeneous composition may mean that the difference in the respective components is 5% or less. The difference in the components may be 3% or less, or may be 1% or less. For example, if the same gas is used when depositing the first protrusions 15 and the second protrusions 17, it is possible to obtain first protrusions 15 and second protrusions 17 having a homogeneous composition.

The first protrusions 15 and the second protrusions 17 may have different compositions, if necessary. For example, if gases with different compositions are used when forming the first protrusions 15 and the second protrusions 17, it is possible to obtain first protrusions 15 and second protrusions 17 with different compositions.

The first protrusions 15 may protrude in a direction perpendicular to the surface 5 of the base 3, or may protrude in a direction inclined to the surface 5 of the base 3. The second protrusions 17 may protrude from a region of the first protrusions 15 excluding the tips 15a of the first protrusions 15, as in the non-limiting example shown in FIG. 4. In this case, it is easier to obtain the effect of the first protrusions 15.

The coating layer 7 is not limited to a specific thickness. For example, the average thickness of the TiCNO layer 9 may be set to 200 to 2000 nm. In this case, the hardness of the TiCNO layer 9 is less likely to decrease, and the Al ₂ O ₃ layer 11 is more likely to have an α-type crystal structure. The thickness of the TiCNO layer 9 is a value excluding the first protrusions 15 and the second protrusions 17. In the case where the TiCNO layer 9 has other protrusions 23, the thickness of the TiCNO layer 9 is a value excluding the other protrusions 23.

The Al ₂ O ₃ layer 11 may have an average thickness of 1 to 15 μm, and may be greater than _the average thickness of _the TiCNO layer 9.

The 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 any position of each layer, and the average value may be calculated.

The TiCNO layer 9 may contain, for example, 30 to 70 atomic % titanium, 1 to 70 atomic % carbon, 1 to 35 atomic % nitrogen, and 3 to 20 atomic % oxygen. The TiCNO layer 9 may further contain aluminum at a rate of 10 atomic % or less, and may further contain components such as chlorine and chromium at a rate of 1 to 10 atomic %. The TiCNO layer 9 may contain other trace components. The first protrusions 15 and the second protrusions 17 may have the same composition, or may have a composition within the above-mentioned range.

Elemental analysis may be performed, for example, by energy dispersive X-ray spectroscopy (EDS). Elemental analysis may also be performed by cross-sectional observation using an EDS attached to an electron microscope.

The coating layer 7 may be located on the entire surface 5 of the substrate 3, or may be located on only a portion of the surface 5. In other words, the coating layer 7 may be located on at least a portion of the surface 5 of the substrate 3.

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. The coating layer 7 may be a physical vapor deposition (PVD) film formed by a PVD method.

Examples of the material of the substrate 3 include hard alloys, ceramics, and metals. Examples of the hard alloys include cemented carbide containing tungsten carbide (WC) and iron group metals such as cobalt (Co) and nickel (Ni). Examples of other hard alloys include titanium carbonitride (TiCN) and Ti-based cermets containing iron group metals. Examples of ceramics include silicon nitride (Si ₃ N ₄ ), alumina (Al ₂ O ₃ ), diamond, and cubic boron nitride (cBN). Examples of metals include carbon steel, high speed steel, and alloy steel.

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

The coated tool 1 may have a first surface 25 (top surface), a second surface 27 (side surface) adjacent to the first surface 25, and a cutting edge 29 located on at least a portion of the ridge between the first surface 25 and the second surface 27.

The first surface 25 may be a rake surface. The first surface 25 may be entirely a rake surface, or only a part of the first surface 25 may be a rake surface. For example, the area of the first surface 25 along the cutting edge 29 may be a rake surface.

The second surface 27 may be a flank. The entire surface of the second surface 27 may be a flank, or only a part of the surface may be a flank. For example, the area of the second surface 27 along the cutting edge 29 may be a flank.

The cutting edge 29 may be located on a portion of the ridgeline, or may be located on the entire ridgeline. The cutting edge 29 can be used to cut the workpiece.

The coated tool 1 may have a through hole 31. The through hole 31 can be used to attach a fixing screw or a clamp member when holding the coated tool 1 in a holder. The through hole 31 may be formed from the first surface 25 to the surface (lower surface) located opposite the first surface 25, and may open in these surfaces. Note that there is no problem with the through hole 31 being configured to open in opposing areas of the second surface 27.

The coated tool 1 may have a rectangular plate shape. Note that the shape of the coated tool 1 is not limited to a rectangular plate shape. For example, the first surface 25 may have a triangular, pentagonal, hexagonal, or circular shape.

The coated tool 1 is not limited to a specific size. For example, the length of one side of the first surface 25 may be set to approximately 3 to 20 mm. In addition, the height from the first surface 25 to the surface (lower surface) located on the opposite side of the first surface 25 may be set to approximately 5 to 20 mm.

Next, another non-limiting aspect of the coated tool 1A of the present disclosure will be described with reference to the drawings. Below, the differences between coated tool 1A and coated tool 1 will be mainly described, and detailed descriptions of the same configuration as coated tool 1 may be omitted. Therefore, the description of coated tool 1 may be used to understand the configuration of coated tool 1A.

7, the coating layer 7 may have, in order from the substrate 3, a first TiCN layer 33, a second TiCN layer 35, a TiCNO layer 9, and _{an Al2O3} layer 11. In this case, the life of the coated tool 1A is likely to be long.

The first TiCN layer 33 may be a so-called MT (moderate temperature)-TiCN layer. The first TiCN layer 33 may have an average thickness set to 2 to 15 μm. In this case, the first TiCN layer 33 has high wear resistance and chipping resistance. The titanium carbonitride crystals contained in the first TiCN layer 33 may be columnar crystals that are elongated in the thickness direction of the coating layer 7.

The second TiCN layer 35 may be a so-called HT (high temperature) TiCN layer. The average thickness of the second TiCN layer 35 may be set to 10 to 900 nm.

The carbon content ratio of the second TiCN layer 35 to the total content of carbon and nitrogen may be lower than the carbon content ratio of the first TiCN layer 33. In this case, the hardness of the first TiCN layer 33 is likely to be improved. As a result, the wear resistance and chipping resistance of the coated tool 1A are likely to be improved. The carbon content ratio means the ratio of the carbon content to the total content of carbon (C) and nitrogen (N) contained [C/(C+N)].

The carbon content of the first TiCN layer 33 may be 0.52 to 0.57, and the carbon content of the second TiCN layer 35 may be 0.42 to 0.51. In this case, the wear resistance and chipping resistance of the coated tool 1A are more likely to be improved. The first TiCN layer 33 may have a carbon content of 15 to 29 atomic % and a nitrogen content of 22 to 35 atomic %. In this case, the wear resistance and chipping resistance of the coated tool 1A are more likely to be improved. The second TiCN layer 35 may have a carbon content of 13 to 24 atomic % and a nitrogen content of 23 to 35 atomic %. In this case, the adhesion between the second TiCN layer 35 and the TiCNO layer 9 is high.

The first TiCN layer 33 may contain titanium at 45-60 atomic %, carbon at 15-29 atomic %, and nitrogen at 22-35 atomic %. In this case, the coated tool 1A has higher wear resistance and chipping resistance. The second TiCN layer 35 may contain titanium at 48-60 atomic %, carbon at 10-20 atomic %, and nitrogen at 15-25 atomic %. In this case, the second TiCN layer 35 is less likely to break, and the adhesion between the second TiCN layer 35 and the TiCNO layer 9 is also high.

Oxygen may be present in the first TiCN layer 33 and the second TiCN layer 35, and the amount of oxygen present in the second TiCN layer 35 may be greater than the amount of oxygen present in the first TiCN layer 33. For example, the first TiCN layer 33 may contain oxygen at a rate of 0.5 atomic % or less. Furthermore, the second TiCN layer 35 may contain oxygen at a rate of 1 to 10 atomic %.

The coating layer 7 may have other layers. For example, the coating layer 7 may have a surface layer. The surface layer may be located at the farthest portion of the coating layer 7 from the substrate 3. For example, the surface layer may be located on the _Al2O3 layer _11. The material of the surface layer may be titanium nitride. That is, the surface layer may be a TiN layer.

The material of the surface layer is not limited to titanium nitride. The material of the surface layer may be, for example, titanium carbonitride, titanium carbonate nitride, chromium nitride, etc. The material of the surface layer may also be colored. In this case, it is easy to determine whether the cutting edge 29 has been used or not. The average thickness of the surface layer may be set to 0.1 to 3 μm.

The coating layer 7 may have an underlayer 37. The underlayer 37 may be located closest to the substrate 3 in the coating layer 7. For example, the underlayer 37 may be located between the substrate 3 and the first TiCN layer 33. The underlayer 37 may function as a layer that inhibits the diffusion of components such as cobalt, carbon, and tungsten into a layer located above the underlayer 37 when the substrate 3 contains these components. The underlayer 37 may also be a TiN layer. The underlayer 37 may be formed as TiCN by the carbon components of the substrate 3 diffusing into TiN. The underlayer 37 may have an average thickness of 0.1 to 1 μm.

<Method of manufacturing coated tools>
Next, a non-limiting method for producing a one-sided coated tool according to the present disclosure will be described.

When manufacturing a coated tool, a substrate may be prepared first. An example will be described in which a substrate made of a hard alloy is prepared as the substrate. First, a mixed powder may be obtained by adding metal powder, carbon powder, etc. to inorganic powder such as carbide, nitride, carbonitride, or oxide, which can form a substrate by firing, and mixing them. Next, this mixed powder may be molded into a predetermined tool shape by a known molding method such as press molding, casting molding, extrusion molding, or cold isostatic pressing. The obtained molded body may then be fired in a vacuum or in a non-oxidizing atmosphere to obtain a substrate made of a hard alloy. The surface of the obtained substrate may be polished or honed.

Next, a coating layer may be formed on the surface of the obtained substrate by a CVD method to obtain a coated tool. The coating layer may have, in order from the substrate, a TiN layer (underlayer), a first TiCN layer (MT-TiCN layer), a second TiCN layer (HT-TiCN layer), a _TiCNO layer, an _Al2O3 layer, and a TiN layer (surface layer), and the respective deposition conditions will be described in order.

When a TiN layer is formed as the underlayer, the film may be formed as follows. First, a mixed gas consisting of 0.5 to 10 volume % titanium tetrachloride (TiCl ₄ ) gas, 10 to 60 volume % nitrogen (N ₂ ) gas, and the remainder hydrogen (H ₂ ) gas may be prepared as the reaction gas composition. Then, this mixed gas may be introduced into the chamber, and the film formation temperature may be set to 800 to 940° C. and the pressure may be set to 8 to 50 kPa to form the TiN layer as the underlayer.

The first TiCN layer (MT-TiCN layer) may be formed as follows. First, a mixed gas consisting of 0.5 to 10 volume % titanium tetrachloride (TiCl ₄ ) gas, 5 to 60 volume % nitrogen (N ₂ ) gas, 0.1 to 3 volume % acetonitrile (CH ₃ CN) gas, and the remainder hydrogen (H ₂ ) gas may be adjusted as the reaction gas composition. Then, this mixed gas may be introduced into the chamber, the film formation 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. If the content ratio of acetonitrile (CH ₃ CN) gas is made higher in the later film formation than in the early film formation, the average crystal width of the titanium carbonitride columnar crystals constituting the first TiCN layer is likely to be larger on the surface side than on the substrate side.

The second TiCN layer (HT-TiCN layer) may be formed as follows. First, a mixed gas consisting of 1 to 4 volume % titanium tetrachloride (TiCl ₄ ) gas, 5 to 20 volume % nitrogen (N ₂ ) gas, 0.1 to 10 volume % methane (CH ₄ ) gas, and the remainder hydrogen (H ₂ ) gas may be prepared as a reaction gas composition. Then, this mixed gas may be introduced into a chamber, and the film formation temperature may be set to 900 to 990° C. and the pressure may be set to 5 to 40 kPa to form the second TiCN layer. The second TiCN layer may be formed at a higher temperature than the first TiCN layer.

The TiCNO layer may be formed as follows. First, a mixed gas may be prepared as a reaction gas composition, which is composed of 3 to 15 volume percent titanium tetrachloride (TiCl ₄ ) gas, 0 to 50 volume percent nitrogen (N ₂ ) gas, 0.2 to 2 volume percent methane (CH ₄ ) gas, 0.5 to 2 volume percent acetonitrile (CH ₃ CN) gas, 0.5 to 10 volume percent carbon monoxide (CO) gas, and the remainder hydrogen (H ₂ ) gas. Then, this mixed gas may be introduced into the chamber, and the film formation temperature may be set to 900 to 990° C. and the pressure to 5 to 40 kPa to form the TiCNO layer. When the TiCNO layer is formed under such film formation conditions, composite protrusions having the first protrusions and the second protrusions having the above-mentioned configuration are easily formed. In addition, the texture coefficient Tc(006) of the Al ₂ O ₃ layer is easily 7.5 or more.

The Al ₂ O ₃ layer may be formed as follows. First, a mixed gas may be prepared as a reaction gas composition, which is 3.5 to 15 volume % aluminum trichloride (AlCl ₃ ) gas, 0.5 to 2.5 volume % hydrogen chloride (HCl) gas, 0.5 to 5 volume % carbon dioxide (CO ₂ ) gas, 0 to 1 volume % hydrogen sulfide (H ₂ S) gas, and the remainder hydrogen (H ₂ ) gas. Then, this mixed gas may be introduced into a chamber, and the film formation temperature may be set to 900 to 990°C and the pressure may be set to 5 to 20 kPa to form the Al ₂ O ₃ layer.

When a TiN layer is to be formed as the surface layer, the film may be formed as follows. First, a mixed gas containing 0.1 to 10 volume % titanium tetrachloride (TiCl ₄ ) gas, 10 to 60 volume % nitrogen (N ₂ ) gas, and the remainder hydrogen (H ₂ ) gas may be prepared as the reaction gas composition. Then, this mixed gas may be introduced into a chamber, and the film formation temperature may be set to 960 to 1100° C. and the pressure may be set to 10 to 85 kPa to form a TiN layer as the surface layer.

In the obtained 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 smooth. Therefore, the workpiece material is less likely to adhere to the tool, and the coated tool tends to have high resistance to wear and chipping.

The above manufacturing method is just one example of a method for manufacturing a coated tool. Therefore, it goes without saying that coated tools are not limited to those manufactured by the above manufacturing method.

<Cutting tools>
Next, a non-limiting one-sided cutting tool 101 according to the present disclosure will be described with reference to the drawings, taking as an example a case in which the cutting tool 1 is provided with the above-mentioned coated tool 1 .

As a non-limiting example shown in FIG. 8, the cutting tool 101 may include a holder 103 extending from a first end 103a to a second end 103b and having a pocket 105 on the side of the first end 103a, and a coated tool 1 located in the pocket 105. When the cutting tool 101 includes the coated tool 1, the coated tool 1 has high wear resistance and chipping resistance, enabling stable cutting.

The pocket 105 may be a portion in which the coated tool 1 is attached. The pocket 105 may open on the outer peripheral surface of the holder 103 and on the end surface on the side of the first end 103a.

The coated tool 1 may be attached to the pocket 105 so that the cutting edge 29 protrudes outward from the holder 103. The coated tool 1 may also be attached to the pocket 105 by a fixing screw 107. That is, the coated tool 1 may be attached to the pocket 105 by inserting the fixing screw 107 into the through hole 31 of the coated tool 1 and inserting the tip of the fixing screw 107 into a screw hole formed in the pocket 105 to screw the threaded portions together. At this time, the bottom surface of the coated tool 1 may be in direct contact with the pocket 105, or a sheet may be sandwiched between the coated tool 1 and the pocket 105.

The material of the holder 103 may be, for example, steel or cast iron. If the material of the holder 103 is steel, the holder 103 has high toughness.

In the example shown in FIG. 8, a cutting tool 101 used for so-called turning is illustrated. Examples of turning include internal diameter machining, external diameter machining, and groove machining. Note that the use of the cutting tool 101 is not limited to turning. For example, there is no problem in using the cutting tool 101 for milling.

The above provides examples of the non-limiting one-sided coated tools 1, 1A and cutting tool 101 of the present disclosure, but 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.

For example, in the above non-limiting embodiment, the coated tool 1 is used as the cutting tool 101, but the coated tool 1 can be used for other purposes. Examples of other uses include wear-resistant parts such as sliding parts and dies, tools such as drilling tools and blades, and impact-resistant parts.

The cutting tool 101 described above includes a coated tool 1, but is not limited to this form. For example, the cutting tool 101 may include a coated tool 1A instead of the coated tool 1.

Moreover, the coated tool 1, 1A and the cutting tool 101 may have the following configuration.
(1) A coated tool comprising a base and a coating layer located on the surface of the base, the coating layer having a TiCNO layer and an Al ₂ O ₃ layer, the Al ₂ O ₃ layer being located in contact with the TiCNO layer at a position farther from the base than the TiCNO layer, the TiCNO layer having a plurality of composite projections each having a first projection protruding toward the Al ₂ O ₃ layer and a second projection protruding from the first projections in a direction intersecting the protruding direction of the first projections, and in a cross section perpendicular to the surface of the base, A, which is the average width of the base of the first projections, is 200 to 1200 nm, and B, which is the average length of the first projections, is 200 to 1000 nm.
(2) In the coated tool described above in (1), the relationship between A and B may satisfy (A/B)>1.
(3) In the coated tool of (1) or (2) above, at least one of the plurality of composite projections may have a plurality of the second projections.
(4) In any one of the coated tools (1) to (3) above, in the cross section, an average width C of the base of the secondary projections may be 20 to 150 nm, and an average length D of the secondary projections may be 20 to 150 nm.
(5) In the coated tool according to (4) above, the relationship between C and D may satisfy (C/D)>1.
(6) In the coated tool according to any one of (1) to (5) above, the texture coefficient Tc(006) of the Al ₂ O ₃ layer may be 7.5 or more.
(7) In the coated tool of any one of (1) to (6) above, the coating layer may have, in order from the substrate, a first TiCN layer, a second TiCN layer, the TiCNO layer, and the Al ₂ O ₃ layer.
(8) The cutting tool may include a holder extending from a first end toward a second end and having a pocket on the first end side, and a coated tool according to any one of (1) to (7) above, located in the pocket.

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

[Samples No. 1 to 6]
<Preparation of coated tools>
First, a substrate was prepared. Specifically, 6% by mass of metal 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 of the powder with an average particle size of 1.5 μm were mixed to obtain a mixed powder. The average particle size of each powder was measured by a microtrack method.

The resulting mixed powder was then press-molded into a tool shape (CNMG120408) to obtain a molded body. The resulting molded body was then subjected to a binder removal process and then sintered in a non-oxidizing atmosphere to obtain a base body made of cemented carbide. The sintering temperature was set at 1450-1600°C, the sintering time was set at 1 hour, and an argon atmosphere was used as the non-oxidizing atmosphere. The resulting base body was then brushed, and the part that would become the cutting edge was R-honed.

Next, a coating layer was formed on the surface of the obtained substrate by a CVD method to obtain the coated tool samples shown in Table 1. For the samples shown in Table 1, a TiN layer was first formed as a base layer on the surface of the substrate, and a first TiCN layer (MT-TiCN layer), a second TiCN layer (HT-TiCN layer), a TiCNO layer, and _{an Al2O3} layer were formed in this order on the TiN layer. The respective film formation conditions were as follows:

(Deposition conditions of TiN layer (underlayer))
First, a mixed gas consisting of 1 volume % titanium tetrachloride ( _TiCl4 ) gas, 38 volume % nitrogen ( _N2 ) gas, and the remainder hydrogen ( _H2 ) gas was prepared as the reaction gas composition. Then, this mixed gas was introduced into the chamber, and the film formation temperature was set to 850°C and the pressure was set to 16 kPa. The film formation time was set to 180 minutes.

(Deposition conditions of first TiCN layer (MT-TiCN layer))
First, a mixed gas consisting of 4 volume % titanium tetrachloride ( _TiCl4 ) gas, 23 volume % nitrogen ( _N2 ) gas, 0.4 volume % acetonitrile ( _CH3CN ) gas, and the remainder hydrogen ( _H2 ) gas was prepared as the reaction gas composition. Then, this mixed gas was introduced into the chamber, and the film formation temperature was set to 850°C and the pressure was set to 9 kPa. The film formation time was set to 400 minutes.

(Deposition conditions of second TiCN layer (HT-TiCN layer))
First, a mixed gas consisting of 4 volume % titanium tetrachloride ( _TiCl4 ) gas, 20 volume % nitrogen ( _N2 ) gas, 8 volume % methane ( _CH4 ) gas, and the remainder hydrogen ( _H2 ) gas was prepared as the reaction gas composition. Then, this mixed gas was introduced into the chamber, and the film formation temperature was set to 950°C and the pressure to 13 kPa. The film formation time was set to 80 minutes.

(Deposition conditions of TiCNO layer)
As shown in Table 1.

( _{Al2O3 layer} deposition conditions)
First, a mixed gas was prepared as a reaction gas composition, which was composed of 3.7 volume % aluminum trichloride (AlCl ₃ ) gas, 0.7 volume % hydrogen chloride (HCl) gas, 4.3 volume % carbon dioxide (CO ₂ ) gas, 0.3 volume % hydrogen sulfide (H ₂ S) gas, and the remainder hydrogen (H ₂ ) gas. Then, this mixed gas was introduced into the chamber, and the film formation temperature was set to 950° C. and the pressure was set to 7.5 kPa. The film formation time was set to 380 minutes.

The obtained coated tool was subjected to SEM observation of a cross section perpendicular to the surface of the substrate. Then, A, which is the average width of the base of the primary projections, B, which is the average length of the primary projections, C, which is the average width of the base of the secondary projections, and D, which is the average length of the secondary projections, were measured according to the method exemplified above. The measurements of A, B, C, and D were performed on one cross section of the rake face at a magnification of 15,000 times and the number of measurements was 10 each. In addition, (A/B) and (C/D) were calculated from the measured A, B, C, and D. Furthermore, the obtained coated tool was subjected to XRD analysis according to the method exemplified above, and the texture coefficient Tc(006) of _{the Al2O3} layer was measured.

The results of each measurement are shown in Table 1. (A/B) is shown in the "A/B" column of Table 1. (C/D) is shown in the "C/D" column of Table 1.

The ratio of composite protrusions was measured for coated tools of samples No. 1 to 4 according to the method exemplified above. As a result, composite protrusions accounted for 60 to 70% of the total protrusions. The total number of protrusions was measured on one cross section of the rake face. The electron microscope used was an SEM. The magnification was 15,000 times. An area of 18.6 μm x 6 μm in the obtained SEM photograph was taken as one field of view. The total number of protrusions was 5 to 20 per field of view in the SEM photograph.

<Evaluation>
The resulting coated tool was subjected to a cutting test under the following conditions.
Processing type: turning Cutting speed: 300 m/min
Feed: 0.3 mm/rev
Cutting depth: 2 mm
Work material: SCM435 φ200 round bar Processing condition: WET

The test results are shown in Table 1. In Table 1, "Cutting time (min) until chipping occurs" refers to the time until the cutting edge is damaged. Also, "Cutting time (min) until 0.2 mm of wear" refers to the time until the wear amount reaches 0.2 mm on the flank of the cutting edge.

Samples No. 1 to 4 showed higher wear resistance and chipping resistance than samples No. 5 to 6.

REFERENCE SIGNS LIST 1 coated tool 3 substrate 5 surface 7 coating layer 9 TiCNO layer 11 _Al2O3 layer ₁₃ composite projection 15 first projection 15a tip 17 second projection 17a tip 17b first side 17c second side 19 base of first projection 19a central portion 21 base of second projection 21a central portion 23 other projection 25 first surface (upper surface)
27...Second surface (side)
29: Cutting edge 31: Through hole 33: First TiCN layer 35: Second TiCN layer 37: Base layer 101: Cutting tool 103: Holder 103a: First end 103b: Second end 105: Pocket 107: Fixing screw A: Average width of base of first projections B: Average length of first projections C: Average width of base of second projections D: Average length of second projections

Claims (8)

A coated tool comprising a substrate and a coating layer disposed on a surface of the substrate,
The coating layer 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;
the TiCNO layer has a plurality of composite protrusions, each of which has a first protrusion protruding toward _{the Al2O3} layer and a second protrusion protruding from the first protrusions in a direction intersecting with the protruding direction of the first protrusions;
the average width A of the base portions of the primary projections is 200 to 1200 nm, and the average length B of the primary projections is 200 to 1000 nm, in a cross section perpendicular to the surface of the base body. The coated tool according to claim 1, in which the relationship between A and B satisfies (A/B)>1. The coated tool according to claim 1 or 2, wherein at least one of the plurality of composite protrusions has a plurality of the second protrusions. The coated tool according to any one of claims 1 to 3, wherein in the cross section, the average width C of the base of the second projections is 20 to 150 nm, and the average length D of the second projections is 20 to 150 nm. The coated tool according to claim 4, wherein the relationship between C and D satisfies (C/D)>1. The coated tool according to any one of claims 1 to 5, wherein _{the Al2O3} layer has a texture coefficient Tc(006) of 7.5 or more. 7. The coated tool according to claim 1, wherein the coating layer comprises, in order from the substrate, a first TiCN layer, a second TiCN layer, the TiCNO layer and the Al ₂ O ₃ layer. a holder extending from a first end to a second end and having a pocket on the first end side;
A cutting tool comprising: the coated tool according to any one of claims 1 to 7, located in the pocket.

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