WO2025197502A1 - Coated tool and cutting tool - Google Patents

Abstract

A coated tool according to one non-limiting embodiment of the present disclosure comprises a base material and a coating layer positioned on the base material. The base material is a super-hard alloy having: a hard phase containing W and C; and a bonding phase containing Co. The base material has a surface region that is present from the surface towards an inner part. The surface region has an average Co content of 5.5-7 mass%, an average Vickers hardness of 1500-1600 Hv, and a standard deviation, which is an indicator of variation in the Co content, of 0.1-0.5 mass %.

Description

Coated tools and cutting tools CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2024-044852, filed March 21, 2024, the entire disclosure of which is incorporated herein by reference.

This disclosure relates to coated tools and cutting tools.

A known example of a coated tool used in cutting tools is the coated tool described in Japanese Patent Laid-Open No. 2015-157327 (Patent Document 1). The coated tool described in Patent Document 1 uses a WC-based cemented carbide tool substrate that contains WC as a hard phase component and Co as a binder phase component. A Co-enriched region is formed in a region 5 to 35 μm deep from the surface of this tool substrate toward the interior. The average Co content in the WC-based cemented carbide tool is 5 to 15 mass%.

A non-limiting aspect of the coated tool disclosed herein is a coated tool comprising a substrate and a coating layer positioned on the substrate. The substrate is a cemented carbide having a hard phase containing W and C and a binder phase containing Co. The substrate has a surface region extending from the surface toward the interior. The surface region has an average Co content of 5.5 to 7 mass%, an average Vickers hardness of 1500 to 1600 Hv, and a standard deviation, which is an index of variation in the Co content, of 0.1 to 0.5 mass%.

FIG. 1 is a perspective view of a non-limiting one-sided coated tool of the present disclosure. 2 is a cross-sectional view of the coated tool shown in FIG. 1 taken perpendicular to the surface of the substrate. 1 is a cross-sectional view showing the vicinity of a surface of a non-limiting coated tool of the present disclosure. 1 is a cross-sectional view showing the vicinity of a surface of a non-limiting coated tool of the present disclosure. FIG. 1 is a perspective view of a non-limiting one-sided cutting tool of the present disclosure.

<Coated tools>
A non-limiting aspect of the coated tool 1 of the present disclosure will be described in detail below with reference to the drawings. However, for the sake of convenience, the drawings referred to below show only the main components necessary for explaining the embodiment in a simplified form. Therefore, the coated tool 1 may include any components not shown in the drawings referred to. Furthermore, the dimensions of the components in the drawings do not faithfully represent the actual dimensions of the components, the dimensional ratios of the components, etc.

The coated tool 1 may include a base 3 and a coating layer 5 positioned on the base 3, as shown in Figures 1 to 4 as a non-limiting example.

The substrate 3 may be a cemented carbide. In other words, the coated tool 1 may have a cemented carbide substrate 3. The cemented carbide may have a hard phase and a binder phase.

The hard phase may contain W (tungsten) and C (carbon). The hard phase may contain W and C as the main components. "Main component" means the component with the largest mass% value compared to other components. Specifically, of the components contained in the hard phase, the top two mass% values may be W and C. The hard phase may contain W and C in the form of WC.

The binder phase may contain Co (cobalt). The binder phase may also contain Co as its main component. That is, Co may have the largest mass percentage of all the components contained in the binder phase. The binder phase may function as a phase that bonds adjacent hard phases together.

The composition of each of the hard phase and binder phase may be measured, for example, by energy dispersive X-ray spectroscopy (EDS). Measurements may be performed using an EDS attached to an electron microscope. Examples of electron microscopes include scanning electron microscopes (SEM) and transmission electron microscopes (TEM).

Here, the substrate 3 may have a surface region 7, as shown in a non-limiting example in Figure 2. The surface region 7 may be present from the surface 9 of the substrate 3 toward the interior of the substrate 3.

The surface region 7 may have the following configuration: The average Co content may be 5.5 to 7 mass %. The average Vickers hardness (Hv) may be 1500 to 1600 Hv. The standard deviation, which is an index of variation in the Co content, may be 0.1 to 0.5 mass %.

When the substrate 3 has a surface region 7 configured in this way, the wear resistance and chipping resistance of the coated tool 1 are likely to be improved. As a result, the coated tool 1 has high wear resistance and chipping resistance. This is presumably because the content of Co, which has the effect of improving the strength and toughness of the substrate 3, is uniform and has little variation in the surface region 7.

The average Co content and standard deviation may be values measured at five locations using EDS. For example, if the thickness of the surface region 7 is 40 μm, the measurement locations may be 6, 14, 22, 30, and 38 μm from the surface 9 in a cross section perpendicular to the surface 9 of the substrate 3, and the average Co content and standard deviation in the surface region 7 may be calculated from the values measured at these five locations. This also applies when measuring other locations other than the surface region 7.

The average Vickers hardness is a value measured when the coated tool 1 is provided with the coating layer 5. Alternatively, the average Vickers hardness may be a value measured in accordance with JIS Z 2244:2009. Specific measurement conditions for the average Vickers hardness may be set, for example, as follows:
Measuring device: INNOVATEST
Push strength: 10 kgf
Atmosphere: Air Measurement temperature: 25°C
Number of measurements: 3
Other: Measurements are made with the coating layer 5 positioned on the substrate 3. A cross section perpendicular to the surface 9 of the substrate 3 is mirror-polished to form a polished surface, which serves as the measurement surface. For mirror polishing, diamond paste with an average particle size of 1 to 3 μm manufactured by Tomei Diamond Co., Ltd. and olive oil manufactured by Yamakei Sangyo Co., Ltd., adjusted to a paste concentration of 20 to 30% by mass, are used. These points are the same when measuring other areas other than the surface region 7.

The surface region 7 may include the surface 9 of the substrate 3. The thickness of the surface region 7 may be 1 to 50 μm. The thickness of the surface region 7 may be measured by cross-sectional observation using an electron microscope.

The substrate 3 may further have an internal region 11, as shown in a non-limiting example in Figure 2. The internal region 11 may extend from the surface region 7 toward the interior. The average Vickers hardness of the internal region 11 may be higher than the average Vickers hardness of the surface region 7. In these cases, the relatively soft surface region 7 tends to mitigate the impact that occurs with the workpiece during cutting. This tends to improve the wear resistance and chipping resistance of the coated tool 1.

The internal region 11 may have the following configuration: The average Co content may be 5.5 to 7 mass %. The average Vickers hardness may be 1520 to 1620 Hv.

The internal region 11 may be in contact with the surface region 7. The thickness of the internal region 11 may be 50 to 150 μm. For example, the thickness of the internal region 11 may be evaluated assuming that it is 100 μm. The thickness of the internal region 11 may also be greater than the thickness of the surface region 7. In other words, the surface region 7 may be thinner than the internal region 11. For example, the thickness of the surface region 7 may be half or less the thickness of the internal region 11. The thickness of the internal region 11 may be measured by cross-sectional observation using an electron microscope.

The coated tool 1 may further include an interface layer 13 at the interface between the substrate 3 and the coating layer 5, as shown in a non-limiting example in Figure 2.

The interface layer 13 may contain Co. In this case, the adhesion between the substrate 3 and the coating layer 5 is likely to be improved.

The average Co content in the interface layer 13 may be 0.1 to 5 mass%.

Interface layer 13 may further contain C. The average C content in interface layer 13 may be 0.1 to 10 mass%.

In the interface layer 13, the Co content may decrease and the C content may increase with increasing distance from the substrate 3. In this case, the adhesion between the substrate 3 and the coating layer 5 is likely to improve.

The interface layer 13 may contain Ti (titanium) as a main component. The composition of the interface layer 13 may be measured, for example, by EDS.

The interface layer 13 may have an average thickness of 0.1 to 1 μm. The thickness of the interface layer 13 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 on the interface layer 13, and the average value may be calculated.

The inner region 11 may not contain beta phase particles made of WC and iron-group metals. In this case, the wear resistance and chipping resistance of the coated tool 1 are likely to be improved. Examples of iron-group metals include Co and Ni (nickel). The absence of beta phase particles may be confirmed, for example, by EDS. The absence of beta phase particles may also be confirmed by cross-sectional observation using an SEM. When an SEM is used for confirmation, it may be determined that no beta phase particles are present if the area ratio of beta phase particles is less than 5%.

The coating layer 5 may be located over the entire surface 9 of the substrate 3, or may be located over only a portion of the surface 9. In other words, the coating layer 5 may be located over at least a portion of the surface 9 of the substrate 3.

The coating layer 5 may be formed by a chemical vapor deposition (CVD) method. In other words, the coating layer 5 may be a CVD film. The coating layer 5 may also be a physical vapor deposition (PVD) film formed by a PVD method.

The coating layer 5 may be a single layer or a laminate of multiple layers, and may include, for example, TiCN (titanium carbonitride), _Al2O3 ( _alumina ), and TiN (titanium nitride).

3, the coating layer 5 may have, in order from the substrate 3 side, a TiCN layer 15 and _{an Al2O3} layer 17. The _Al2O3 layer 17 may be in contact with the _TiCN layer 15.

4, the coating layer 5 may have, from the substrate 3 side, a TiN layer 19, a TiCN layer 15, and an _Al2O3 layer 17. The TiCN layer 15 may be in contact with the TiN layer _{19. The Al2O3} layer 17 may be in contact with the TiCN layer 15.

The coating layer 5 is not limited to a specific thickness. For example, the TiCN layer 15 may have an average thickness of about 1 to 15 μm. The _{Al 2} O ₃ layer 17 may have an average thickness of about 1 to 15 μm. The TiN layer 19 may have an average thickness of about 0.1 to 5 μm. The thickness of the coating layer 5 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 in each layer, and the average value may be calculated.

In Figure 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 a cutting insert.

The coated tool 1 may have a first surface 21 (top surface), a second surface 23 (side surface) adjacent to the first surface 21, and a cutting edge 25 located at the intersection of the first surface 21 and the second surface 23.

The first surface 21 may be a rake surface. The entire first surface 21 may be a rake surface, or only a portion of the first surface 21 may be a rake surface. For example, the area of the first surface 21 along the cutting edge 25 may be a rake surface.

The second surface 23 may be a flank. The entire second surface 23 may be a flank, or only a portion of the second surface 23 may be a flank. For example, the area of the second surface 23 along the cutting edge 25 may be a flank.

The cutting edge 25 may be located over the entire intersection of the first surface 21 and the second surface 23, or may be located over only a portion of this intersection. The cutting edge 25 can be used to cut a workpiece when manufacturing a machined product using the coated tool 1.

The coated tool 1 may have a through hole 27. The through hole 27 can be used to attach a screw or a clamp member when fixing the coated tool 1 to a holder. The through hole 27 may be formed from the first surface 21 to the surface opposite the first surface 21 (the lower surface), or may open in these surfaces. Note that there is no problem if the through holes 27 are configured to open in opposing areas of the second surface 23.

The coated tool 1 may have a rectangular plate shape. However, the shape of the coated tool 1 is not limited to a rectangular plate shape. For example, the first surface 21 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 21 may be set to approximately 3 to 20 mm. Furthermore, the height from the first surface 21 to the surface located opposite the first surface 21 (the lower surface) may be set to approximately 5 to 20 mm.

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

When manufacturing a coated tool, a substrate may be prepared first. First, raw material powders such as WC powder, Co powder, _Cr3C2 powder, and TaC powder may be prepared. The proportion of Co powder may be 5.5 to 7 mass %. The proportion of _{Cr3C2 powder} may be 0.1 to 5 mass %. The proportion of _TaC powder may be 0.1 to 5 mass %. The remainder may be WC powder.

The average particle size of the raw material powder may be selected appropriately from the range of 0.1 to 10 μm. The average particle size of the raw material powder may be a value measured using the microtrack method.

The prepared raw material powders may be mixed and molded to obtain a molded body. Examples of molding methods include press molding, casting, extrusion molding, and cold isostatic pressing.

The resulting molded body may be subjected to a binder removal process and then fired. The firing temperature may be 1450 to 1600°C. The firing time may be 0.5 to 3 hours.

The firing may be performed in an atmosphere of a mixed gas of argon (Ar) gas and methane (CH ₄ ) gas. In this mixed gas, the argon gas may be present in a larger amount than the methane gas. When firing is performed in such a mixed gas atmosphere, the surface region having the above-described structure is easily formed. Also, the internal region having the above-described structure is easily formed. The mixed gas may be 60 to 99 volume % argon gas, with the remainder being methane gas.

After firing, the substrate may be cooled to obtain a substrate made of cemented carbide. A coating layer may then be formed on the substrate using the CVD method to obtain a coated tool.

The TiCN layer may be formed as follows: First, a mixed gas containing 0.1 to 10 volume percent titanium tetrachloride (TiCl ₄ ) gas, 5 to 60 volume percent nitrogen (N ₂ ) gas, 0.1 to 3 volume percent acetonitrile (CH ₃ CN) 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 temperature may be set to 800 to 1100°C and the pressure may be set to 5 to 30 kPa to form the TiCN layer.

_{The Al2O3} layer may be formed as follows. First, a mixed gas containing 0.5 to 5 volume percent aluminum trichloride ( _AlCl3 ) gas, 0.5 to 3.5 volume percent hydrogen chloride (HCl) gas, 0.5 to 5 volume percent carbon dioxide ( _CO2 ) gas, 0.5 to 5 volume percent hydrogen sulfide ( _H2S ) gas, and the remainder hydrogen ( _H2 ) gas may be prepared as the reaction gas composition. Then, this mixed gas may be introduced into a chamber, and the temperature may be set to 930 to 1010°C and the pressure may be set to 5 to 10 kPa to form _{the Al2O3} layer.

The TiN layer may be formed as follows: First, a mixed gas containing 0.1 to 10 volume percent titanium tetrachloride (TiCl ₄ ) gas, 10 to 60 volume percent 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 temperature may be set to 800 to 1010°C and the pressure may be set to 10 to 85 kPa to form the TiN layer.

Heat treatment may be performed after forming the layer closest to the substrate (the bottom layer). In this case, elements of the substrate and/or the bottom layer diffuse to the interface between the two, making it easier to form the interface layer having the above-mentioned configuration. The conditions for the heat treatment may be set, for example, as follows:
Treatment temperature: 900 to 1000°C
Processing time: 0.1 to 2 hours

Note that the above manufacturing method is 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 of the present disclosure will be described with reference to the drawings, taking as an example a case where the cutting tool 1 is provided with the above-described coated tool 1 .

The cutting tool 101 may include a holder 103 and a coated tool 1, as shown in a non-limiting example in FIG. 5. The holder 103 may extend from the first end 103a toward the 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 the coated tool 1, the coated tool 1 has high wear resistance and chipping resistance, enabling stable cutting.

The pocket 105 may be the portion where the coated tool 1 is attached. The pocket 105 may be 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 at least a portion of the cutting edge 25 protrudes from the holder 103. Alternatively, the coated tool 1 may be attached to the pocket 105 with a screw 107. That is, the coated tool 1 may be attached to the pocket 105 by inserting the screw 107 into the through-hole 27 of the coated tool 1 and then inserting the tip of the screw 107 into a threaded hole formed in the pocket 105 to secure the screw 107 in the threaded hole. At this time, the underside 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.

Examples of materials for the holder 103 include steel and cast iron. If the holder 103 is made of steel, the holder 103 has high toughness.

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

The above provides examples of non-limiting examples of the coated tool 1 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 other suitable embodiment as long as it does not deviate from the gist of the present disclosure.

For example, the coated tool 1 and the cutting tool 101 may have the following configuration.
[1] A coated tool includes a substrate and a coating layer located on the substrate, the substrate being a cemented carbide having a hard phase containing W and C and a binder phase containing Co, and having a surface region extending from the surface toward the interior, the surface region having an average Co content of 5.5 to 7 mass %, an average Vickers hardness of 1500 to 1600 Hv, and a standard deviation, which is an index of variation in the Co content, of 0.1 to 0.5 mass %.
[2] In the coated tool of [1] above, the substrate may further have an internal region extending from the surface region toward the interior, and the average Vickers hardness of the internal region may be higher than the average Vickers hardness of the surface region.
[3] In the coated tool of [2] above, the inner region may have an average Co content of 5.5 to 7 mass % and an average Vickers hardness of 1520 to 1620 Hv.
[4] The coated tool according to any one of the above [1] to [3] may further comprise an interface layer at the interface between the substrate and the coating layer.
[5] In the coated tool of the above [4], the interface layer may contain Co.
[6] In the coated tool of the above [5], the average content of Co in the interface layer may be 0.1 to 5 mass %.
[7] In the coated tool of the above [5] or [6], the interface layer may further contain C, and the content of Co may decrease and the content of C may increase with increasing distance from the base.
[8] In the coated tool according to any one of the above [2] to [7], the inner region may be free of β-phase grains made of WC and iron-group metals.
[9] In the coated tool of any one of the above [1] to [8], the coating layer may have, from the substrate side, a TiCN layer and an Al ₂ O ₃ layer in this order.
[10] In the coated tool of any one of the above [1] to [8], the coating layer may have, from the substrate side, a TiN layer, a TiCN layer, and an Al ₂ O ₃ layer in this order.
[11] A cutting tool may include a holder extending from a first end to a second end and having a pocket on the side of the first end, and a coated tool according to any one of [1] to [10] above, positioned in the pocket.

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

[Samples No. 1 to 4]
<Preparation of coated tools>
First, the substrate is prepared. Specifically, the WC powder with an average particle size of 9 μm, the Co powder with an average particle size of 1.5 μm, the _Cr3C2 powder _with an average particle size of 1.5 μm, and the TaC powder with an average particle size of 0.9 μm are prepared as raw material powder. The average particle size of the raw material powder is measured by the microtrack method.

Next, 5.5% by mass of Co powder, 0.2% by mass of _{Cr3C2 powder} , 0.3% by mass of TaC powder, and the remainder of WC powder were mixed and pressed into a cutting tool shape (CNMA120412) to obtain a molded body. This molded body was subjected to a binder removal treatment and then sintered.

The firing conditions were set as follows:
Firing temperature: 1450°C,
Firing time: 1 hour Atmosphere: As shown in Table 1.

In the "Atmosphere" column of Table 1, "Mixed gas" means that the compact was fired in a mixed gas. The mixed gas used contained more argon gas than methane gas. The mixed gas used for samples 1 and 3 was the same mixed gas. Also, "Argon" means that the compact was fired in argon gas. "Vacuum" means that the compact was fired in a vacuum.

After firing, the substrate was cooled to obtain a substrate made of cemented carbide. The composition of the cemented carbide in this substrate was measured using EDS. Specifically, cross-sections were observed using an EDS attached to an SEM at a magnification of 5,000 to 20,000 times, and measurements were taken at five locations, taking the average value. Five elements were selected for measurement using EDS: tungsten carbide, cobalt, chromium, tantalum, and carbon.

EDS measurements showed that all of the obtained cemented carbide alloys contained a hard phase and a binder phase. More specifically, all of the obtained cemented carbide alloys contained a hard phase containing WC as the main component and a binder phase containing Co as the main component.

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. The coating layers were formed in the order of a TiN layer, a TiCN layer, and _{an Al2O3} layer from the substrate side. The respective film formation conditions were as follows:

(TiN layer deposition conditions)
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. This mixed gas was then introduced into a chamber, and the temperature and pressure were set to 850°C and 18 kPa, respectively. The film formation time was set to 180 minutes.

(TiCN layer deposition conditions)
First, a mixed gas containing 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. This mixed gas was then introduced into a chamber, and the temperature and pressure were set to 850°C and 9 kPa, respectively. The film formation time was set to 400 minutes.

( _{Al2O3 layer} deposition conditions)
First, a mixed gas containing 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 hydrogen ( _H2 ) gas was prepared as the reaction gas composition. This mixed gas was then introduced into a chamber, and the temperature and pressure were set to 950°C and 7.5 kPa, respectively. The film formation time was set to 380 minutes.

For Sample No. 1, the heat treatment was carried out after forming the TiN layer, which was the layer closest to the substrate (the bottom layer). The heat treatment conditions were set as follows:
Treatment temperature: 950°C
Processing time: 1 hour

In the obtained coated tool, the substrate had a surface region 40 μm thick and an internal region 100 μm thick. The average Co content and standard deviation for the surface region, and the average Co content for the internal region were measured according to the methods exemplified above. The average Vickers hardness in the surface region and internal region was also measured according to the methods exemplified above. The measurement results are shown in Table 1. The average Co content is shown in the "Average Co Amount (mass%)" column. The average Vickers hardness is shown in the "Vickers Hardness (Hv)" column.

The presence or absence of an interface layer was measured for the obtained coated tools using EDS. The measurement results are shown in the "Presence or absence of interface layer" column in Table 1.

<Evaluation>
The coated tool was subjected to a cutting test under the following test conditions, and the test results are shown in Table 1.

Processing method: turning Cutting speed: 180 m/min
Feed: 0.4 mm/rev
Cutting depth: 1.5 mm
Work material: FCD700 φ200 round bar Processing condition: WET
Evaluation items: Check the wear width (mm) and damage width (mm) after 15 minutes of processing. Other: Measurements were performed with n=2, and the average value was calculated.

The results for wear width after 15 minutes of machining are shown in the "Wear Width (mm)" column. The smaller the wear width value, the higher the wear resistance. The results for damage width after 15 minutes of machining are shown in the "Damage Width (mm)" column. The smaller the damage width value, the higher the chipping resistance.

Samples No. 1 and 3 demonstrated high wear resistance and chipping resistance. Furthermore, a wear width of 0.20 mm or less can be considered to have high wear resistance.

For samples No. 1 and 3, cross-sectional observation using an SEM was performed to confirm that the internal regions contained no beta phase particles. As a result, in samples No. 1 and 3, the area ratio of beta phase particles was less than 5%, and the internal regions contained no beta phase particles.

Sample No. 1 had an interface layer. The composition of this interface layer was measured using EDS. The EDS measurement conditions were the same as those used to measure the composition of the cemented carbide. The EDS measurement results showed that this interface layer contained Co and C.

The average Co and C contents were also measured using the method exemplified above. The results showed that the average Co content was 2% by mass, and the average C content was 4% by mass. In the interface layer, the Co content decreased and the C content increased with increasing distance from the substrate.

The interface layer contained Ti as its main component. The average thickness of the interface layer was measured using the method exemplified above. Measurements were performed at 10 measurement points using an SEM. The average thickness of the interface layer was found to be 0.2 μm.

1... Covered tool 3... Base 5... Coating layer 7... Surface region 9... Surface 11... Internal region 13... Interface layer 15... TiCN layer ₁₇ ... _Al2O3 layer 19... TiN layer 21... First surface (top surface)
23...Second side (side)
25: Cutting blade 27: Through hole 101: Cutting tool 103: Holder 103a: First end 103b: Second end 105: Pocket 107: Screw

Claims (11)

a substrate;
a coating layer disposed on the substrate,
The substrate is
A cemented carbide having a hard phase containing W and C and a binder phase containing Co,
a surface region extending from the surface toward the interior;
The surface region is
The average content of Co is 5.5 to 7 mass %,
The average Vickers hardness is 1500 to 1600 Hv,
The coated tool has a standard deviation, which is an index of variation in the Co content, of 0.1 to 0.5 mass%. the substrate further has an interior region extending from the surface region toward the interior,
The coated tool of claim 1 , wherein the average Vickers hardness of the interior region is greater than the average Vickers hardness of the surface region. The inner region is
The average content of Co is 5.5 to 7 mass %,
3. The coated tool according to claim 2, wherein the coated tool has an average Vickers hardness of 1520 to 1620 Hv. The coated tool according to any one of claims 1 to 3, further comprising an interface layer at the interface between the substrate and the coating layer. The coated tool according to claim 4, wherein the interface layer contains Co. The coated tool according to claim 5, wherein the average Co content in the interface layer is 0.1 to 5 mass%. The interface layer is
Further containing C,
7. The coated tool according to claim 5, wherein the Co content decreases and the C content increases with increasing distance from the substrate. A coated tool according to any one of claims 2 to 7, wherein the internal region does not contain β-phase particles composed of WC and iron-group metals. 9. The coated tool according to claim 1, wherein the coating layer comprises a TiCN layer and an Al ₂ O ₃ layer in this order from the substrate side. 9. The coated tool according to claim 1, wherein the coating layer comprises, in order from the substrate side, a TiN layer, a TiCN layer, and an Al ₂ O ₃ layer. a holder extending from a first end to a second end and having a pocket on the side of the first end;
A cutting tool comprising: the coated tool according to any one of claims 1 to 10 located in the pocket.