JP7507887B2 - Coated and cutting tools - Google Patents

Description

The present disclosure relates to coated tools and cutting tools.

As tools used in cutting processes such as turning and milling, coated tools are known in which the surface of a substrate made of cemented carbide, cermet, ceramics, etc. is coated with a coating film to improve wear resistance, etc. (see Patent Document 1). Also known is a coated tool in which part of the coating film has been removed to expose part of the substrate (see Patent Document 2).

JP 2002-3284 A Patent No. 4500810

A coated tool according to one embodiment of the present disclosure is a coated tool having a substrate and a coating film located on the substrate. The coated tool has a first surface, a second surface, and a third surface located between the first surface and the second surface, the third surface being a C-plane or an R-plane. The substrate is made of a boron nitride sintered body containing a plurality of cubic boron nitride particles. The substrate is exposed at the first surface. The coating film is located on the second surface.

A cutting tool according to one aspect of the present disclosure has a rod-shaped holder having a pocket at an end and the above-mentioned coated tool positioned within the pocket.

FIG. 1 is a perspective view showing an example of a coated tool according to an embodiment. FIG. 2 is a side cross-sectional view showing an example of a coated tool according to an embodiment. FIG. 3 is a schematic enlarged view of part III shown in FIG. FIG. 4 is a schematic enlarged view of part IV shown in FIG. FIG. 5 is a schematic enlarged view of the V portion shown in FIG. FIG. 6 is a front view illustrating an example of a cutting tool according to an embodiment.

Below, the form for implementing the coated tool and cutting tool according to the present disclosure (hereinafter, referred to as "embodiment") will be described in detail with reference to the drawings. Note that the coated tool and cutting tool according to the present disclosure are not limited to this embodiment. Furthermore, each embodiment can be appropriately combined to the extent that the processing content is not contradictory. Furthermore, the same parts in each of the following embodiments are given the same reference numerals, and duplicate explanations will be omitted.

In addition, in the embodiments described below, expressions such as "constant," "orthogonal," "vertical," and "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "vertical," or "parallel" in the strict sense. In other words, each of the above expressions allows for deviations due to, for example, manufacturing precision, installation precision, and the like.

There are known coated tools that have improved wear resistance and other properties by coating the surface of a substrate such as cemented carbide, cermet, or ceramic with a coating film. However, there is room for further improvement in durability of these types of coated tools.

<Coated tools>
Fig. 1 is a perspective view showing an example of a coated tool according to an embodiment. As shown in Fig. 1, the coated tool 1 according to the embodiment has a tip body 2 and a cutting edge portion 3. The coated tool 1 according to the embodiment has, for example, a hexahedral shape in which the upper and lower surfaces (surfaces intersecting with the Z-axis shown in Fig. 1) are parallelogram shapes.

(Chip body 2)
The tip body 2 is formed of, for example, a cemented carbide. The cemented carbide contains W (tungsten), specifically WC (tungsten carbide). The cemented carbide may also contain at least one of Ni (nickel) and Co (cobalt). The tip body 2 may also be formed of a cermet. The cermet contains, for example, Ti (titanium), specifically TiC (titanium carbide) or TiN (titanium nitride). The cermet may also contain Ni or Co.

At the corners of the tip body 2, there are seating surfaces 4 for attaching the cutting edge portion 3. At the center of the tip body 2, there is a through hole 5 that passes vertically through the tip body 2. A screw 75 is inserted into the through hole 5 for attaching the coated tool 1 to the holder 70 described later (see FIG. 6).

(Cutting edge portion 3)
The cutting edge portion 3 is attached to a seat surface 4 of the tip body 2 and is thereby integrated with the tip body 2 .

The cutting edge portion 3 has a first surface 6 (here, the top surface) and a second surface 7 (here, the side surface) that is connected to the first surface 6. In the embodiment, the first surface 6 functions as a "scooping surface" that scoops up chips generated by cutting, and the second surface 7 functions as a "flank surface." A cutting edge 8 is located on at least a portion of the ridge where the first surface 6 and the second surface 7 intersect. The coated tool 1 cuts the workpiece by applying the cutting edge 8 to the workpiece.

The configuration of the cutting edge portion 3 will be described with reference to Fig. 2. Fig. 2 is a side cross-sectional view showing an example of a coated tool 1 according to an embodiment. As shown in Fig. 2, the cutting edge portion 3 has a base body 10 and a coating film 20.

(Base 10)
The substrate 10 contains a plurality of boron nitride particles. In the embodiment, the substrate 10 is a cubic boron nitride (cBN) sintered body, and is made of a boron nitride sintered body containing a plurality of cubic boron nitride particles. The substrate 10 may have a binder phase containing TiN, Al, Al ₂ O ₃ , or the like between the plurality of boron nitride particles. The plurality of boron nitride particles are firmly bonded by such a binder phase. It is not necessary for the substrate 10 to have a binder phase.

The cutting edge 8 has a third surface 9 that is continuous with the first surface 6 and the second surface 7. The third surface 9 is, for example, a C surface (chamfered surface) in which the corner between the first surface 6 and the second surface 7 is cut obliquely and linearly. However, the third surface 9 may also be an R surface (rounded surface) in which the corner between the first surface 6 and the second surface 7 is rounded.

A substrate 30 made of, for example, cemented carbide or cermet may be located on the underside of the base 10. In this case, the base 10 is joined to the seating surface 4 of the chip body 2 via the substrate 30 and a joining material 40. The joining material 40 is, for example, a brazing material. In the portion other than the seating surface 4 of the chip body 2, the base 10 may be joined to the chip body 2 via the joining material 40.

(Coating film 20)
The coating film 20 is applied to the base 10 for the purpose of improving the wear resistance, heat resistance, etc. of the cutting edge portion 3. In the example of Fig. 2, the coating film 20 is located on both the tip body 2 and the cutting edge portion 3, but it is sufficient that the coating film 20 is located at least on the base 10. When the coating film 20 is located on the side surface of the base 10 corresponding to the second surface 7 of the cutting edge portion 3, the wear resistance and heat resistance of the second surface 7 are high.

3 is a schematic enlarged view of part III shown in FIG. 2. As shown in FIG. 3, in the coated tool 1 according to the embodiment, the substrate 10 is exposed at the first surface 6. In other words, the coating film 20 is not present on the first surface 6. In the coated tool 1 according to the embodiment, the coating film 20 is located on the second surface 7 and the third surface 9.

As a result of extensive research, the inventors of the present application have found that the durability of the coated tool 1 is improved when the coating film 20 is not provided on the first surface 6, which corresponds to the rake face, compared to when the coating film 20 is provided on the first surface 6. The reason for this is thought to be that, for example, when the coating film 20 is broken, the base material 10, which is the base material, is also damaged.

Therefore, in the coated tool 1 according to the embodiment, the second surface 7 corresponding to the flank face and the third surface 9 corresponding to the cutting edge 8 are covered with the coating film 20, while the first surface 6 corresponding to the rake face is exposed. The coated tool 1 having such a configuration has high durability.

The coated tool 1 according to the embodiment has a coating film 20 on the second surface 7, which corresponds to the flank face, and on the third surface 9, which corresponds to the cutting edge 8. The coated tool 1 having such a configuration has high wear resistance and heat resistance. It is sufficient that the coated tool 1 has the coating film 20 on at least the second surface 7.

The thickness of the coating film 20 on the third surface 9 may be thinner than the thickness of the coating film 20 on the second surface 7. By reducing the thickness of the coating film 20 on the second surface 7, damage to the entire substrate 10 when the coating film 20 is broken is suppressed. Therefore, the coated tool 1 having such a configuration has even higher durability. For example, the thickness of the coating film 20 on the second surface 7 may be 0.5 μm or more and 5.0 μm or less. Also, the thickness of the coating film 20 on the third surface 9 may be 0.01 μm or more and less than 5.0 μm.

The thickness of the coating film 20 on the third surface 9 may be thinner in the region closer to the first surface 6 than in the region closer to the second surface 7. For example, the thickness of the coating film 20 located on the third surface 9 may gradually increase from the first surface 6 toward the second surface 7. A coated tool 1 having such a configuration has a good balance of chipping resistance, wear resistance, and heat resistance.

(Specific configuration of coating film 20)
Next, a specific configuration of the coating film 20 will be described with reference to Fig. 4. Fig. 4 is a schematic enlarged view of part IV shown in Fig. 3.

As shown in FIG. 4, the coating film 20 has at least a hard layer 21. The hard layer 21 has one or more metal nitride layers. The hard layer 21 may be a single layer. Also, as shown in FIG. 4, a plurality of metal nitride layers may be overlapped. Also, the hard layer 21 may have a laminated portion 23 in which a plurality of metal nitride layers are laminated, and a third metal nitride layer 24 located on the laminated portion 23. The configuration of the hard layer 21 will be described later.

(Metal Layer 22)
The coating film 20 may also have a metal layer 22. The metal layer 22 is located between the substrate 10 and the hard layer 21. Specifically, the metal layer 22 contacts the upper surface of the substrate 10 on one side (the lower surface here) and contacts the lower surface of the hard layer 21 on the other side (the upper surface here).

The metal layer 22 has higher adhesion to the substrate 10 than the hard layer 21. Examples of metal elements having such properties include Zr, V, Cr, W, Al, Si, and Y. The metal layer 22 contains at least one of the above metal elements.

Note that elemental Ti, elemental Zr, elemental V, elemental Cr, and elemental Al are not used as the metal layer 22. These elements all have low melting points and low oxidation resistance, making them unsuitable for use in cutting tools. Also, elemental Hf, elemental Nb, elemental Ta, and elemental Mo have low adhesion to the substrate 10. However, this does not apply to alloys containing Ti, Zr, V, Cr, Ta, Nb, Hf, and Al.

The metal layer 22 may be an Al-Cr alloy layer containing an Al-Cr alloy. Such a metal layer 22 has particularly high adhesion to the substrate 10, and is therefore highly effective in improving adhesion between the substrate 10 and the coating film 20.

When the metal layer 22 is an Al-Cr alloy layer, the Al content in the metal layer 22 may be greater than the Cr content in the metal layer 22. For example, the composition ratio (atomic %) of Al to Cr in the metal layer 22 may be 70:30. With such a composition ratio, the adhesion between the substrate 10 and the metal layer 22 is higher.

The metal layer 22 may contain components other than the above metal elements (Zr, V, Cr, W, Al, Si, Y). However, from the viewpoint of adhesion to the substrate 10, the metal layer 22 may contain at least 95 atomic % or more of the above metal elements in total. More preferably, the metal layer 22 may contain 98 atomic % or more of the above metal elements in total. For example, when the metal layer 22 is an Al-Cr alloy layer, the metal layer 22 may contain at least 95 atomic % or more of Al and Cr in total. Furthermore, the metal layer 22 may contain at least 98 atomic % or more of Al and Cr in total. The proportion of the metal components in the metal layer 22 can be determined, for example, by analysis using EDS (energy dispersive X-ray spectrometry).

In addition, since Ti has poor wettability with the substrate 10 according to the embodiment, it is preferable that the metal layer 22 contains as little Ti as possible from the viewpoint of improving adhesion with the substrate 10. Specifically, the Ti content in the metal layer 22 may be 15 atomic % or less.

In this way, in the coated tool 1 according to the embodiment, the metal layer 22, which has higher wettability with the substrate 10 than the hard layer 21, is provided between the substrate 10 and the hard layer 21, thereby improving the adhesion between the substrate 10 and the coating film 20. In addition, since the metal layer 22 also has high adhesion with the hard layer 21, the hard layer 21 is unlikely to peel off from the metal layer 22.

In addition, the cBN used as the substrate 10 is an insulator. As an insulator, there is room for improvement in the adhesion of cBN to a film formed by PVD (physical vapor deposition). In contrast, in the coated tool 1 according to the embodiment, by providing a conductive metal layer 22 on the surface of the substrate 10, the adhesion between the hard layer 21 formed by PVD and the metal layer 22 is high.

(Hard layer 21)
Next, the configuration of the hard layer 21 will be described with reference to Fig. 5. Fig. 5 is a schematic enlarged view of the V portion shown in Fig. 4.

As shown in FIG. 5, the hard layer 21 has a laminate portion 23 located on the metal layer 22 and a third metal nitride layer 24 located on the laminate portion 23.

The laminated portion 23 has a plurality of first metal nitride layers 23a and a plurality of second metal nitride layers 23b. The laminated portion 23 has a configuration in which the first metal nitride layers 23a and the second metal nitride layers 23b are alternately laminated.

The thickness of the first metal nitride layer 23a and the second metal nitride layer 23b may each be 50 nm or less. In this way, by forming the first metal nitride layer 23a and the second metal nitride layer 23b thin, the residual stress of the first metal nitride layer 23a and the second metal nitride layer 23b is small. As a result, for example, peeling or cracking of the first metal nitride layer 23a and the second metal nitride layer 23b is less likely to occur, and the durability of the coating film 20 is high.

The first metal nitride layer 23a is a layer in contact with the metal layer 22, and the second metal nitride layer 23b is formed on the first metal nitride layer 23a.

The first metal nitride layer 23a and the second metal nitride layer 23b may contain the metal contained in the metal layer 22.

For example, suppose that metal layer 22 contains two types of metals (here, "first metal" and "second metal"). In this case, first metal nitride layer 23a contains nitrides of the first metal and a third metal. The third metal is a metal that is not contained in metal layer 22. Furthermore, second metal nitride layer 23b contains nitrides of the first metal and a second metal.

For example, in an embodiment, the metal layer 22 may contain Al and Cr. In this case, the first metal nitride layer 23a may contain Al. Specifically, the first metal nitride layer 23a may be an AlTiN layer containing AlTiN, which is a nitride of Al and Ti. Also, the second metal nitride layer 23b may be an AlCrN layer containing AlCrN, which is a nitride of Al and Cr.

In this way, by positioning the first metal nitride layer 23a containing the metal contained in the metal layer 22 on the metal layer 22, the adhesion between the metal layer 22 and the hard layer 21 is high. This makes it difficult for the hard layer 21 to peel off from the metal layer 22, and therefore the durability of the coating film 20 is high.

The first metal nitride layer 23a, i.e., the AlTiN layer, has excellent adhesion to the metal layer 22, as described above, and also has excellent wear resistance. The second metal nitride layer 23b, i.e., the AlCrN layer, has excellent heat resistance and oxidation resistance, for example. In this way, the coating film 20 includes the first metal nitride layer 23a and the second metal nitride layer 23b, which have different compositions, and thus the characteristics of the hard layer 21, such as wear resistance and heat resistance, can be controlled. This can extend the tool life of the coated tool 1. For example, in the hard layer 21 according to the embodiment, mechanical properties such as adhesion to the metal layer 22 and wear resistance can be improved while maintaining the excellent heat resistance of AlCrN.

The laminated portion 23 may be formed by, for example, an arc ion plating method (AIP method). The AIP method is a method of forming a metal nitride (here, AlTiN and AlCrN) film by evaporating a target metal (here, an AlTi target and an AlCr target) using arc discharge in a vacuum atmosphere and combining it with _N2 gas. The metal layer 22 may also be formed by the AIP method.

The third metal nitride layer 24 may be located on the laminated portion 23. Specifically, the third metal nitride layer 24 contacts the second metal nitride layer 23b of the laminated portion 23. The third metal nitride layer 24 is, for example, a metal nitride layer (AlTiN layer) containing Ti and Al, similar to the first metal nitride layer 23a.

The thickness of the third metal nitride layer 24 may be thicker than the thicknesses of the first metal nitride layer 23a and the second metal nitride layer 23b. Specifically, when the thicknesses of the first metal nitride layer 23a and the second metal nitride layer 23b are 50 nm or less as described above, the thickness of the third metal nitride layer 24 may be 1 μm or more. For example, the thickness of the third metal nitride layer 24 may be 1.2 μm.

As a result, for example, when the friction coefficient of the third metal nitride layer 24 is low, the adhesion resistance of the coated tool 1 can be improved. Also, for example, when the hardness of the third metal nitride layer 24 is high, the wear resistance of the coated tool 1 can be improved. Also, for example, when the oxidation onset temperature of the third metal nitride layer 24 is high, the oxidation resistance of the coated tool 1 can be improved.

The thickness of the third metal nitride layer 24 may be thicker than the thickness of the laminated portion 23. Specifically, in an embodiment, when the thickness of the laminated portion 23 is 0.5 μm or less, the thickness of the third metal nitride layer 24 may be 1 μm or more. For example, when the thickness of the laminated portion 23 is 0.3 μm, the thickness of the third metal nitride layer 24 may be 1.2 μm. In this way, by making the third metal nitride layer 24 thicker than the laminated portion 23, the effect of improving the above-mentioned adhesion resistance, wear resistance, etc. is further enhanced.

The thickness of the metal layer 22 may be, for example, 0.1 μm or more and less than 0.6 μm. That is, the metal layer 22 may be thicker than each of the first metal nitride layer 23a and the second metal nitride layer 23b, and thinner than the laminate portion 23.

The hard layer 21 may contain cubic crystals. Here, the X-ray intensity of the (200) plane in the cubic crystal is I(200), and the X-ray intensity of the (111) plane is I(111). In this case, I(200)/I(111) may be 5.3 or more. The coated tool 1 having such a configuration has excellent impact resistance and the hard layer 21 is not easily peeled off.

<Cutting tools>
Next, a configuration of a cutting tool including the above-mentioned coated tool 1 will be described with reference to Fig. 6. Fig. 6 is a front view showing an example of a cutting tool according to an embodiment.

As shown in FIG. 6, the cutting tool 100 of the embodiment has a coated tool 1 and a holder 70 for fixing the coated tool 1.

The holder 70 is a rod-shaped member extending from a first end (upper end in FIG. 6) to a second end (lower end in FIG. 6). The holder 70 is made of, for example, steel or cast iron. Of these materials, it is particularly preferable to use steel, which has high toughness.

The holder 70 has a pocket 73 at the end on the first end side. The pocket 73 is the portion where the coated tool 1 is attached, and has a seating surface that intersects with the rotation direction of the workpiece and a restraining side surface that is inclined relative to the seating surface. The seating surface is provided with a screw hole into which a screw 75 (described later) is screwed.

The coated tool 1 is located in the pocket 73 of the holder 70 and is attached to the holder 70 by a screw 75. That is, the screw 75 is inserted into the through hole 5 of the coated tool 1, and the tip of the screw 75 is inserted into a screw hole formed in the seating surface of the pocket 73 to screw the threaded portions together. As a result, the coated tool 1 is attached to the holder 70 so that the cutting edge 8 (see FIG. 1) protrudes outward from the holder 70.

In the embodiment, a cutting tool used for so-called turning is exemplified. Examples of turning include internal diameter machining, external diameter machining, and grooving. Note that cutting tools are not limited to those used for turning. For example, the coated tool 1 may be used as a cutting tool used for milling.

For example, cutting of a workpiece includes (1) a step of rotating the workpiece, (2) a step of bringing the cutting edge 8 of the coated tool 1 into contact with the rotating workpiece to cut the workpiece, and (3) a step of removing the coated tool 1 from the workpiece. Representative examples of the material of the workpiece include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

Below, examples of the present disclosure are described. Note that the present disclosure is not limited to the following examples.

First, TiN raw material powder with a concentration of 72% by volume to 82% by volume, Al raw material powder with a concentration of 13% by volume to 23% by volume, and _{Al2O3 raw} material powder with a concentration of 1% by volume to 11% by volume are prepared. An organic solvent is then added to each of the prepared raw material powders. As the organic solvent, alcohols such as acetone and isopropyl alcohol (IPA) can be used. Then, the raw material powders are pulverized and mixed in a ball mill for 20 hours to 24 hours. After pulverization and mixing, the solvent is evaporated to obtain a first mixed powder.

Next, cBN powder having an average particle size of 2.5 μm to 4.5 μm and cBN powder having an average particle size of 0.5 μm to 1.5 μm are mixed in a volume ratio of 8 to 9:1 to 2.0. An organic solvent is then added. As the organic solvent, alcohols such as acetone and IPA can be used. The mixture is then pulverized and mixed in a ball mill for 20 to 24 hours. After pulverization and mixing, the solvent is evaporated to obtain a second mixed powder.

Next, the first mixed powder and the second mixed powder are mixed in a volume ratio of 68 to 78:22 to 32. An organic solvent and an organic binder are added to the mixed powder. As the organic solvent, alcohols such as acetone and IPA can be used. As the organic binder, paraffin, acrylic resin, etc. can be used. After that, the mixture is pulverized and mixed in a ball mill for 20 to 24 hours, and then the organic solvent is evaporated to obtain a third mixed powder. In addition, a dispersant may be added as necessary in the process using the ball mill.

Then, the third mixed powder is molded into a predetermined shape to obtain a molded body. Known methods such as uniaxial pressing and cold isostatic pressing (CIP) can be used for molding. The molded body is heated to a predetermined temperature in the range of 500°C to 1000°C to evaporate and remove the organic binder.

Next, the molded body is placed in an ultra-high pressure heating device and heated at 1200°C to 1500°C for 15 minutes to 30 minutes under a pressure of 4 GPa to 6 GPa. This produces a cubic boron nitride sintered body according to the embodiment. The resulting cubic boron nitride sintered body is then attached to the seat of a tip body made of cemented carbide via a bonding material. This produces the tip according to the embodiment.

Next, a jig of the same size as the obtained chip is placed on the top surface (scooping surface) of the chip. In other words, the top surface (scooping surface) of the chip is covered with the jig. As a result, the scooping surface is in contact with the jig, and no film is formed on the scooping surface. The jig is also positioned above the third surface 9 with a gap therebetween. As a result, the film thickness formed on the third surface 9 is thinner than the film thickness formed on the second surface 7. In this state, a coating film is formed on the surface of the chip by physical vapor deposition (PVD). This results in a coated tool according to the embodiment in which the flank and chamfer surfaces are covered with the coating film and the scooping surface is exposed.

The above-mentioned jig is located near the chamfer surface of the chip. Therefore, deposition on the chamfer surface is suppressed by the above-mentioned jig. As a result, the thickness of the coating film located on the chamfer surface is thinner than the thickness of the coating film located on the relief surface.

As Comparative Example 1, a sample was prepared in which a coating film was formed on the entire surface of the substrate without using the above-mentioned jig. Also, as Comparative Example 2, a sample was prepared in which the coating film was removed from the third surface 9 of the coated tool according to Comparative Example 1.

(Intermittent evaluation)
Next, an intermittent cutting evaluation was carried out under the following cutting conditions for the coated tool according to the example and the coated tool according to the comparative example in which all the faces including the rake face were covered with a coating film.
<Cutting conditions>
Cutting method: Turning Workpiece: SCM415 8 holes Cutting speed: 150 m/min Feed: 0.2 mm/rev
Cut: 0.2 mm
Cutting condition: Wet Evaluation method: Number of impacts until cutting edge is chipped

As a result of the intermittent evaluation, the cutting tool according to the embodiment achieved the longest life. Also, the cutting tool according to the comparative example 1 had the shortest life.

The number of impacts required for the cutting edge to break in the coated tool according to the embodiment was more than twice as many as the number of impacts required for the cutting edge to break in the coated tool according to the comparative example. As is clear from these results, exposing the rake face improves durability and extends the tool life.

In the above embodiment, an example is shown in which the shape of the upper and lower surfaces of the coated tool 1 is a parallelogram, but the shape of the upper and lower surfaces of the coated tool 1 may be a rhombus, a square, etc. Also, the shape of the upper and lower surfaces of the coated tool 1 may be a triangle, a pentagon, a hexagon, etc.

The shape of the coated tool 1 may be either a positive type or a negative type. The positive type is a type in which the side surface is inclined with respect to a central axis passing through the center of the upper surface and the center of the lower surface of the coated tool 1, and the negative type is a type in which the side surface is parallel to the central axis.

In the above-described embodiment, an example in which the substrate 10 contains particles of cubic boron nitride (cBN) has been described. The substrate disclosed in the present application may contain particles of hexagonal boron nitride (hBN), rhombohedral boron nitride (rBN), wurtzite boron nitride (wBN), etc., without being limited thereto. The substrate 10 may be, for example, a cemented carbide or a cermet, etc., without being limited to boron nitride. The cemented carbide contains W (tungsten), specifically WC (tungsten carbide). The cemented carbide may contain Ni (nickel) or Co (cobalt). The cermet contains, for example, Ti (titanium), specifically TiC (titanium carbide) or TiN (titanium nitride). The cermet may contain Ni or Co.

In the above-described embodiment, the coated tool 1 is described as being used for cutting processing, but the coated tool according to the present application can also be used for tools other than cutting tools, such as drilling tools and blades.

Further advantages and modifications may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Thus, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof.

REFERENCE SIGNS LIST 1 Coated tool 2 Tip body 3 Cutting edge portion 4 Seat surface 5 Through hole 6 First surface 7 Second surface 8 Cutting edge 9 Third surface 10 Base body 20 Coating film 21 Hard layer 22 Metal layer 23 Laminated portion 23a First metal nitride layer 23b Second metal nitride layer 24 Third metal nitride layer 30 Substrate 40 Bonding material 70 Holder 73 Pocket 75 Screw 100 Cutting tool

Claims (16)

A substrate;
a coating film disposed on the substrate,
The coated tool comprises:
The first page and
The second side,
a third surface located between the first surface and the second surface, the third surface being a C-surface or an R-surface;
the substrate is made of a boron nitride sintered body containing a plurality of cubic boron nitride particles;
the substrate is exposed over the entire first surface,
the coating film is located on the second surface and the third surface ;
a thickness of the coating film on the third surface is smaller than a thickness of the coating film on the second surface;
A coated tool , wherein the thickness of the coating film on the third surface gradually decreases from the second surface toward the first surface . 2. The coated tool according to claim 1 , wherein the coating film has a thickness on the second surface of not less than 0.5 μm and not more than 5.0 μm, and the coating film has a thickness on the third surface of not less than 0.01 μm and less than 5.0 μm. The coating film is
A hard layer;
The coated tool according to claim 1 or 2 , further comprising: a metal layer other than a simple substance selected from the group consisting of Ti, Zr, V, Cr, Ta, Nb, Hf and Al, located between the substrate and the hard layer. 4. The coated tool according to claim 3 , wherein the metal layer contains at least one element selected from the group consisting of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y. The coated tool according to claim 4 , wherein the metal layer contains the element in an amount of 95 atomic % or more. 6. The coated tool according to claim 5 , wherein the metal layer contains Al and Cr in a total amount of 95 atomic % or more. The coated tool according to claim 3 , wherein the Ti content in the metal layer is 15 atomic % or less. The coated tool according to claim 3 , wherein the substrate has a binder phase between the cubic boron nitride particles. The coated tool according to claim 3 , wherein the hard layer has one or more metal nitride layers, and the metal nitride layer in contact with the metal layer contains the metal contained in the metal layer. The metal nitride layer is
a first metal nitride layer;
10. The coated tool of claim 9 , comprising: a second metal nitride layer having a different composition than the first metal nitride layer. The coated tool of claim 10 , wherein the first metal nitride layer and the second metal nitride layer each have a thickness of 50 nm or less. the metal layer comprises a first metal and a second metal;
the first metal nitride layer contains a nitride of the first metal and a third metal;
The coated tool of claim 10 or 11 , wherein the second metal nitride layer contains nitrides of the first metal and the second metal. the first metal nitride layer contains Ti and Al;
The coated tool of claim 12 , wherein the second metal nitride layer contains Al and Cr. The hard layer is
a stacked section including a plurality of the first metal nitride layers and a plurality of the second metal nitride layers, the first metal nitride layers and the second metal nitride layers being stacked alternately;
a third metal nitride layer located at a position farther from the substrate than the stacked portion,
The thickness of the third metal nitride layer is
The coated tool according to claim 10 , wherein the thickness of the first metal nitride layer is greater than that of the second metal nitride layer. The hard layer contains cubic crystals,
In the cubic crystal, the X-ray intensity of the (200) plane is I(200) and the X-ray intensity of the (111) plane is I(111).
The coated tool according to claim 3 , wherein the I(200)/I(111) is 5.3 or more. a rod-shaped holder having a pocket at one end;
A cutting tool comprising: a coated tool according to any one of claims 1 to 15 located in the pocket.

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