Coated cutting tools and cutting tools

Abstract

The coated cutting tool (1) of the present invention has a substrate (10) and a coating film (20). The substrate (10) contains a plurality of boron nitride particles. The coating film (20) is located on the substrate (10). In addition, the coating film (20) includes a hard layer (21) and a metal layer (22) other than the simple substances of Ti, Zr, V, Cr, Ta, Nb, Hf, and Al located between the substrate (10) and the hard layer (21).

Description

Technical Field

[0001] The present invention relates to coated cutting tools and cutting tools. Background Art

[0002] As a tool used in cutting operations such as turning or hobbing, a coated cutting tool is known in which the surface of a substrate made of cemented carbide, cermet, ceramic, etc. is coated with a coating film to improve wear resistance and the like (see Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent No. 5160231 Summary of the Invention

[0006] A coated cutting tool according to one aspect of the present invention has a substrate and a coating film. The substrate contains a plurality of boron nitride particles. The coating film is located on the substrate. Further, the coating film includes a hard layer; and a metal layer other than the simple substances of Ti, Zr, V, Cr, Ta, Nb, Hf, and Al located between the substrate and the hard layer. Brief Description of the Drawings

[0007] Figure 1 is a perspective view showing an example of a coated cutting tool according to an embodiment.

[0008] Figure 2 is a side cross-sectional view showing an example of a coated cutting tool according to an embodiment.

[0009] Figure 3 is a cross-sectional view showing an example of a coating film according to an embodiment.

[0010] Figure 4 is Figure 3 a schematic enlarged view of the H portion shown.

[0011] Figure 5 is a front view showing an example of a cutting tool according to an embodiment.

[0012] Figure 6 is a table showing the structures of cBN without a metal layer and cBN with a metal layer.

[0013] Figure 7 is a table showing the results of an indentation hardness test for cBN without a metal layer and cBN with a metal layer.

[0014] Figure 8 is a table showing the results of a scratch test and a peeling test for cBN without a metal layer and cBN with a metal layer.

[0015] Figure 9It is a diagram showing the results of XRD measurements of metal - free layer cBN and metal - layer cBN.

[0016] Figure 10 It shows Figure 9 In the diagram shown, it is a table of the X - ray intensity I(111) of the (111) plane, I(200) of the (200) plane, and their orientation ratio I(200) / I(111). Detailed implementation mode

[0017] Hereinafter, while referring to the attached drawings, the methods for implementing the coated cutting tool and the cutting tool of the present invention (hereinafter, described as "implementation mode") will be described in detail. Also, the coated cutting tool and the cutting tool of the present invention are not limited by this implementation mode. In addition, the respective implementation modes can be appropriately combined within the range where there is no contradiction in the processing content. In addition, in the following respective implementation modes, the same reference numerals are added to the same parts, and repeated explanations are omitted.

[0018] In addition, in the implementation modes shown below, there are cases where expressions such as "constant", "orthogonal", "perpendicular", or "parallel" are used, but these expressions do not need to be "constant", "orthogonal", "perpendicular", or "parallel" in the strict sense. That is, the above - mentioned respective expressions allow for deviations such as manufacturing accuracy and setting accuracy.

[0019] In the above - mentioned prior art, there is room for further improvement in enhancing the adhesion between the coating film and the substrate.

[0020] In view of the above, the present invention provides a coated cutting tool and a cutting tool capable of enhancing the adhesion between the coating film and the substrate.

[0021] <Coated cutting tool>

[0022] Figure 1 It is a perspective view showing an example of the coated cutting tool of the implementation mode. As Figure 1 shown, the coated cutting tool 1 of the implementation mode has a blade body 2 and an edge part 3. In the implementation mode, the coated cutting tool 1, for example, has a parallelepiped shape with an upper surface and a lower surface (a surface intersecting the Z - axis shown). Figure 1 shown, the shape of the parallelepiped is a parallelogram.

[0023] (Blade body 2)

[0024] The blade body 2 is formed of, for example, cemented carbide. The cemented carbide contains W (tungsten), specifically, contains WC (tungsten carbide). In addition, the cemented carbide may also contain Ni (nickel) and Co (cobalt). In addition, the blade body 2 may also be formed of cermet. The cermet, for example, contains Ti (titanium), specifically, contains TiC (titanium carbide) or TiN (titanium nitride). In addition, the cermet may also contain Ni and Co.

[0025] The support surface 4 for mounting the cutting edge portion 3 is located at the corner of the blade body 2. In addition, a through hole 5 that penetrates the blade body 2 vertically is located at the center of the blade body 2. In the through hole 5, a bolt 75 (see Figure 5 ) for mounting the coated cutting tool 1 on the tool holder 70, which will be described later, is inserted.

[0026] (Cutting edge portion 3)

[0027] The cutting edge portion 3 is integrated with the blade body 2 by being mounted on the support surface 4 of the blade body 2.

[0028] The cutting edge portion 3 has a first surface 6 (here, the upper surface) and a second surface 7 (here, the side surface) connected to the first surface 6. In the embodiment, the first surface 6 functions as a "rake face" for scraping off the chips generated by cutting, and the second surface 7 functions as a "flank face". The cutting edge 8 is located at at least a part of the ridge line where the first surface 6 and the second surface 7 intersect, and the coated cutting tool 1 cuts the workpiece by bringing this cutting edge 8 into contact with the workpiece.

[0029] Refer to Figure 2 to describe the structure of the cutting edge portion 3. Figure 2 is a side cross-sectional view showing an example of the coated cutting tool 1 of the embodiment. As Figure 2 shown, the cutting edge portion 3 has a substrate 10 and a coating film 20.

[0030] (Substrate 10)

[0031] The substrate 10 contains a plurality of boron nitride particles. In the embodiment, the substrate 10 is a cubic boron nitride (cBN) sintered body containing a plurality of cubic boron nitride particles. In addition, in the embodiment, the substrate 10 may also have a bonding phase containing TiN, Al, Al2O3, etc. between the plurality of boron nitride particles. The plurality of boron nitride particles are firmly bonded by such a bonding phase. Also, the substrate 10 does not necessarily have to have a bonding phase.

[0032] On the lower surface of the substrate 10, a substrate 30 formed of, for example, cemented carbide or cermet may be provided. In this case, the substrate 10 is joined to the support surface 4 of the blade body 2 via the substrate 30 and the joining material 40. The joining material 40 is, for example, a solder. The substrate 10 may be joined to the blade body 2 via the joining material 40 at a portion other than the support surface 4 of the blade body 2.

[0033] (Coating film 20)

[0034] The coating film 20 is coated on the substrate 10, for example, for the purpose of improving the wear resistance, heat resistance, etc. of the cutting edge portion 3. In Figure 2In the example, the coating film 20 entirely covers the blade body 2 and the cutting edge portion 3. The coating film 20 only needs to be located on the substrate 10 at least. Additionally, the coating film 20 may also be located on the blade body 2. When the coating film 20 is located on the upper surface of the substrate 10 corresponding to the first surface 6 of the cutting edge portion 3, the wear resistance and heat resistance of the first surface 6 are high. When the coating film 20 is located on the side surface of the substrate 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.

[0035] Here, refer to Figure 3 The specific configuration of the coating film 20 will be described. Figure 3 It is a cross-sectional view showing an example of the coating film 20 of the embodiment.

[0036] As Figure 3 shown, the coating film 20 has a hard layer 21. The hard layer 21 is a layer with excellent wear resistance compared to the metal layer 22 described later. The hard layer 21 has one or more metal nitride layers. The hard layer 21 may also be one layer. Additionally, as Figure 3 shown, multiple metal nitride layers may also be stacked. Additionally, the hard layer 21 may have a stacked portion 23 formed by stacking multiple metal nitride layers and a third metal nitride layer 24 located above the stacked portion 23. The configuration of such a hard layer 21 will be described later.

[0037] (Metal layer 22)

[0038] Additionally, the coating film 20 has a metal layer 22. The metal layer 22 is located between the substrate 10 and the hard layer 21. Specifically, the metal layer 22 is in contact with the upper surface of the substrate 10 on one surface (here, the lower surface), and is in contact with the lower surface of the hard layer 21 on the other surface (here, the upper surface).

[0039] The adhesion of the metal layer 22 to the substrate 10 is higher than that of the hard layer 21. As metal elements having such characteristics, for example, Zr, V, Cr, W, Al, Si, Y can be cited. The metal layer 22 contains at least one or more of the above metal elements.

[0040] Furthermore, Ti single substance, Zr single substance, V single substance, Cr single substance, and Al single substance are not used as the metal layer 22. This is because they all have low melting points and low oxidation resistance, so they are not suitable for use in cutting tools. Additionally, Hf single substance, Nb single substance, Ta single substance, and Mo single substance have low adhesion to the substrate 10. However, alloys containing Ti, Zr, V, Cr, Ta, Nb, Hf, and Al are not subject to this limitation.

[0041] The metal layer 22 may be an Al - Cr alloy layer containing an Al - Cr alloy. Such a metal layer 22 has a particularly high adhesion to the substrate 10, so the effect of improving the adhesion between the substrate 10 and the coating film 20 is high.

[0042] When the metal layer 22 is an Al-Cr alloy layer, the content of Al in the metal layer 22 can be more than the content of Cr in the metal layer 22. For example, the composition ratio (atomic %) of Al to Cr in the metal layer 22 can be 70:30. By having such a composition ratio, the adhesion between the substrate 10 and the metal layer 22 is higher.

[0043] The metal layer 22 may also 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 Al and Cr in total of 95 atomic % or more. In addition, the metal layer 22 may also contain at least Al and Cr in total of 98 atomic % or more. Further, the ratio of the metal components in the metal layer 22 can be specified by analysis using, for example, EDS (Energy Dispersive X-ray Spectrometer).

[0044] In addition, the wettability of Ti with the substrate 10 of the embodiment is poor. Therefore, from the viewpoint of improving the adhesion to the substrate 10, the metal layer 22 preferably contains as little Ti as possible. Specifically, the content of Ti in the metal layer 22 can be 15 atomic % or less.

[0045] Thus, in the coated cutting tool 1 of the embodiment, by providing a metal layer 22 having a higher wettability with the substrate 10 between the substrate 10 and the hard layer 21, the adhesion between the substrate 10 and the coating film 20 can be improved. Further, since the adhesion between the metal layer 22 and the hard layer 21 is also high, it is also difficult for the hard layer 21 to peel off from the metal layer 22.

[0046] In addition, cBN used as the substrate 10 is an insulator, and for an insulator cBN, there is room for improvement in the adhesion to a film formed by the PVD method (Physical Vapor Deposition). In contrast, in the coated cutting tool 1 of the embodiment, a conductive metal layer 22 is provided on the surface of the substrate 10, so that the adhesion between the hard layer 21 formed by PVD and the metal layer 22 is high.

[0047] (Hard layer 21)

[0048] Next, Figure 4 The configuration of the hard layer 21 will be described. Figure 4 is Figure 3 a schematic enlarged view of the H part shown.

[0049] As Figure 4As shown, the hard layer 21 has a stacked portion 23 above the metal layer 22 and a third metal nitride layer 24 above the stacked portion 23.

[0050] The stacked portion 23 has a plurality of first metal nitride layers 23a and a plurality of second metal nitride layers 23b. The stacked portion 23 has a structure in which the first metal nitride layers 23a and the second metal nitride layers 23b are alternately stacked.

[0051] The thicknesses of the first metal nitride layer 23a and the second metal nitride layer 23b can be 50 nm or less, respectively. By forming the first metal nitride layer 23a and the second metal nitride layer 23b thinly in this way, the residual stresses of the first metal nitride layer 23a and the second metal nitride layer 23b are small. Thus, for example, peeling and cracking of the first metal nitride layer 23a and the second metal nitride layer 23b are difficult to occur, and therefore the durability of the coating film 20 is high.

[0052] 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.

[0053] The first metal nitride layer 23a and the second metal nitride layer 23b may also contain the metals contained in the metal layer 22.

[0054] For example, the metal layer 22 contains two metals (here, "first metal" and "second metal"). In this case, the first metal nitride layer 23a contains a nitride of the first metal and a third metal. The third metal is a metal not contained in the metal layer 22. In addition, the second metal nitride layer 23b contains a nitride of the first metal and the second metal.

[0055] 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. In addition, the second metal nitride layer 23b may be an AlCrN layer containing AlCrN which is a nitride of Al and Cr.

[0056] In this way, by disposing the first metal nitride layer 23a containing the metals contained in the metal layer 22 above the metal layer 22, the adhesion between the metal layer 22 and the hard layer 21 is high. Thus, since the hard layer 21 is difficult to peel from the metal layer 22, the durability of the coating film 20 is high.

[0057] The first metal nitride layer 23a, namely the AlTiN layer, is excellent in abrasion resistance, for example, in addition to the adhesiveness to the above-mentioned metal layer 22. Further, the second metal nitride layer 23b, namely the AlCrN layer, is excellent in heat resistance and oxidation resistance, for example. Thus, by including the first metal nitride layer 23a and the second metal nitride layer 23b having different compositions, the coating film 20 can control characteristics such as the abrasion resistance and heat resistance of the hard layer 21. Thereby, the tool life of the coated tool 1 can be extended. For example, in the hard layer 21 of the embodiment, the excellent heat resistance possessed by AlCrN can be maintained, and at the same time, mechanical characteristics such as the adhesiveness to the metal layer 22 and abrasion resistance can be improved.

[0058] Further, the stacked portion 23 can also be formed by, for example, an arc ion plating method (AIP method). The AIP method is a method of evaporating target metals (here, an AlTi target and an AlCr target) by arc discharge in a vacuum atmosphere and forming metal nitrides (here, AlTiN and AlCrN) by combining with N2 gas. Further, the metal layer 22 can also be formed by the AIP method.

[0059] The third metal nitride layer 24 can be located above the stacked portion 23. Specifically, the third metal nitride layer 24 is in contact with the second metal nitride layer 23b in the stacked portion 23. The third metal nitride layer 24 is, for example, a metal nitride layer (AlTiN layer) containing Ti and Al, like the first metal nitride layer 23a.

[0060] The thickness of the third metal nitride layer 24 can be thicker than the respective 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 can be 1 μm or more. For example, the thickness of the third metal nitride layer 24 can be 1.2 μm.

[0061] Thereby, for example, if the friction coefficient of the third metal nitride layer 24 is low, the anti-bonding property of the coated tool 1 can be improved. Further, for example, if the hardness of the third metal nitride layer 24 is high, the abrasion resistance of the coated tool 1 can be improved. Further, for example, if the oxidation start temperature of the third metal nitride layer 24 is high, the oxidation resistance of the coated tool 1 can be improved.

[0062] In addition, the thickness of the third metal nitride layer 24 can be greater than the thickness of the stacked portion 23. Specifically, in the embodiment, when the thickness of the stacked portion 23 is 0.5 μm or less, the thickness of the third metal nitride layer 24 can be 1 μm or more. For example, when the thickness of the stacked portion 23 is 0.3 μm, the thickness of the third metal nitride layer 24 can be 1.2 μm. Thus, making the third metal nitride layer 24 thicker than the stacked portion 23 can achieve a higher improvement effect in the above-mentioned anti-adhesion property, wear resistance, etc.

[0063] Furthermore, the thickness of the metal layer 22 can be, for example, 0.1 μm or more and less than 0.6 μm. That is, the metal layer 22 can be thicker than the thicknesses of the first metal nitride layer 23a and the second metal nitride layer 23b respectively, and can be thinner than the stacked portion 23.

[0064] <Cutting Tool>

[0065] Next, with reference to Figure 5 , the structure of the cutting tool having the above-mentioned coated tool will be described. Figure 5 FIG. is a front view showing an example of the cutting tool of the embodiment.

[0066] As Figure 5 shown, the cutting tool 100 of the embodiment includes a coated tool 1 and a tool shank 70 for fixing the coated tool 1.

[0067] The tool shank 70 is a rod-shaped member extending from the first end ( Figure 5 the upper end in Figure 5 ) toward the second end (

[0068] the lower end in

[0069] ). The tool shank 70 is made of, for example, steel or cast iron. Among these members, steel with high toughness is particularly preferably used. The tool shank 70 has a clamping groove 73 at the end on the first end side. The clamping groove 73 is the part for mounting the coated tool 1, and has a support surface intersecting the rotation direction of the workpiece to be cut and a limiting side surface inclined with respect to the support surface. On the support surface, there is a bolt hole for tightening a bolt 75 described later. Figure 1 ) The coated tool 1 is located in the clamping groove 73 of the tool shank 70 and is mounted on the tool shank 70 by a bolt 75. That is, the bolt 75 is inserted into the through hole 5 of the coated tool 1, and the front end of the bolt 75 is inserted into the bolt hole formed in the support surface of the clamping groove 73, and the threaded portions are tightened together. Thus, the coated tool 1 is mounted on the tool shank 70 such that the cutting edge 8 (refer to

[0070] In the embodiment, the example is a cutting tool for so-called turning. As turning, for example, inner diameter processing, outer diameter processing and grooving processing can be cited. In addition, the cutting tool is not limited to turning. For example, the cutting tool for hobbing can also use the coated tool 1.

[0071] For example, the cutting process of the 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 separating the coated tool 1 from the workpiece. Representative examples of the material of the workpiece include carbon steel, alloy steel, stainless steel, cast iron, or nonferrous metals.

[0072] (Example 1: Scratch test and peel test)

[0073] The inventors of the present application conducted a scratch test and a peel test on a sample having a coating film formed on cBN. Figure 6 is a table showing the composition of cBN without metal layer and cBN with metal layer. Figure 7 This is a table showing the results of indentation hardness tests on cBN without a metal layer and cBN with a metal layer.

[0074] Set on the surface of the tool-shaped cBN sintered body Figure 6 A metal layer having the composition shown in the table is provided on top of the metal layer. Figure 6 The hard layer (with metal layer cBN) shown in the table. In addition, a cBN sintered body is directly provided Figure 6 The hard layer shown in the table is used as a comparative example (cBN without a metal layer). In addition, a cBN sintered body with a binder is used.

[0075] These samples were subjected to scratch and peel tests. The scratch test was evaluated based on the peel load. The larger the peel load, the harder it was to peel. In addition, the longer the peel time, the harder it was to peel.

[0076] The scratch test was performed using a diamond indenter with a tip shape having an R (radius of curvature) of 200 μm at a speed of 10 mm / min and a load of 100 N for 1 minute.

[0077] The peeling test was conducted on a quenched material of SCM415, using a sample with a tool shape of CNGA120408S01225, with a cutting speed of 150 m / min, a feed rate of 0.1 mm / turn, and a cutting depth of 0.2 mm, and the time until the hard layer peeled off was evaluated.

[0078] The peel load and peel time are shown in Figure 8 middle. Figure 8This is a table showing the results of scratch tests and peel tests for metal-free layer cBN and metal-layered cBN. As Figure 8 shown, the metal-layered cBN has a larger peel load and a significantly longer peel time compared to the metal-free layer cBN. Also, Figure 8 in, "80>" means that the peel load is less than 80 N but close to 80 N (at least 75 N or more). Similarly, Figure 8 in, "40>" means that the peel time is less than 40 minutes but close to 40 minutes (at least 35 minutes or more). Thus, compared with the metal-free layer cBN, the peeling of the coating is less likely to occur for the metal-layered cBN, that is, the durability of the coating is high.

[0079] Also, Figure 7 The indentation hardness test shown in is performed using a micro-indentation hardness tester "ENT-1100b / a" (manufactured by Elionix, Inc.).

[0080] Before measuring the hardness, the thickness of the coating is first measured in a cross-section of the substrate orthogonal to the substrate surface. The thickness of the coating is 2.7 μm when there is a metal layer. When there is no metal layer, the thickness of the coating is 2.5 μm. From the surface of the coating, the indenter is pressed into an amount of 20% of the coating thickness. The indenter is pressed into the coating surface by approximately 0.02 μm each time. This indentation depth can be deepened by increasing the indentation load. The so-called increase in the indentation depth by 0.02 μm each time is, in other words, equivalent to increasing the indentation load by approximately 5 mN each time.

[0081] In this test, if the indenter is pressed into a depth of 20% of the coating thickness, the hardness near the substrate surface can basically be measured from the surface of the coating. In the present invention, the hardness of the coating, as described above, is the hardness obtained by pressing the indenter into a depth of 20% of the coating while changing the indentation load of the indenter from the surface of the coating. In the indentation hardness test, the deeper the indentation depth, the harder it is to measure the hardness of the region deeper from the coating surface.

[0082] (Example 2: XRD measurement)

[0083] The inventors of the present application performed XRD measurement on a sample having a coating formed on cBN. The results are shown in Figure 9 and Figure 10 . Figure 9 This is a graph showing the results of XRD measurement of metal-free layer cBN and metal-layered cBN. Additionally, Figure 10 This is a table showing the X-ray intensity I(111) of the (111) plane, I(200) of the (200) plane, and the orientation ratio I(200) / I(111) in the graph shown in Figure 9 .

[0084] In addition, this experiment was carried out using a thin-film X-ray diffractometer "X'Pert PRO-MRD (DY2295)" (manufactured by PANalytical). The optical system of this instrument consists of an X-ray mirror and a flat collimator. Additionally, the X-ray tube of this instrument is CuKα, with an output power of 45 kV / 40 mA.

[0085] In addition, the measurement conditions for this experiment are as follows.

[0086] Measurement method: 2θ scan

[0087] Measurement range: 20° to 80°

[0088] Incident angle: 0.5°

[0089] Step: 0.02°

[0090] Time: 4.0 sec / step

[0091] The specimens are the following two types.

[0092] (1) (cBN with a metal layer) in which a coating film with a metal layer is formed on cBN

[0093] (2) (cBN without a metal layer) in which a coating film without a metal layer is formed on cBN

[0094] Figure 9 The XRD measurement results of cBN with a metal layer and cBN without a metal layer are shown. Also, from the perspective of easy viewing, Figure 9 in, the overall X-ray intensity of the measurement result of cBN without a metal layer is shifted 500 to the high-intensity side.

[0095] In Figure 9 there is a diffraction peak with a peak in the range of 36° to 38°, which corresponds to the (111) plane of the cubic crystal of the metal nitride contained in the coating film. Additionally, there is a diffraction peak with a peak in the range of 42° to 44°, which corresponds to the (200) plane of the same cubic crystal.

[0096] As Figure 10 shown, in cBN with a metal layer, the X-ray intensity I(111) of the (111) plane is 507, and the X-ray intensity I(200) of the (200) plane is 3135, and their orientation ratio I(200) / I(111) is 6.183432. On the other hand, in cBN without a metal layer, the X-ray intensity I(111) of the (111) plane is 582, and the X-ray intensity I(200) of the (200) plane is 3007, and these orientation ratios I(200) / I(111) are 5.166667.

[0097] Thus, by providing a metal layer on the coating film, a coated cutting tool having an orientation ratio I(200) / I(111) of 5.3 or more can be obtained. The coated cutting tool having such a configuration has a high hardness of the hard layer and excellent wear resistance.

[0098] In addition, in the metal layer cBN, the residual stress of the hard layer based on the (311) plane of the cubic crystal is less than 0 MPa and greater than -1150 MPa. The coated cutting tool having such a configuration has excellent impact resistance and the hard layer is difficult to peel off.

[0099] <Variation Example>

[0100] In the above-described embodiment, the coated cutting tool 1 obtained by mounting a substrate 10 formed of boron nitride particles or the like on a blade body 2 formed of cemented carbide or the like and coating it with a coating film 20 is described. However, the coated cutting tool of the present invention is not limited thereto. For example, the coated cutting tool of the present invention may be a tool in which the entire parallelepiped-shaped substrate having a parallelogram shape on the upper and lower surfaces is a cubic boron nitride sintered body and a coating film is formed on such a substrate.

[0101] In the above-described embodiment, an example in which the upper and lower surfaces of the coated cutting tool 1 have a parallelogram shape is shown. However, the upper and lower surfaces of the coated cutting tool 1 may also have a rhombus or square shape. In addition, the upper and lower surfaces of the coated cutting tool 1 may have a triangular, pentagonal, hexagonal or other shape.

[0102] In addition, the shape of the coated cutting tool 1 may be a positive type or a negative type. The positive type is a type in which the side surface is inclined with respect to the central axis passing through the center of the upper surface and the center of the lower surface of the coated cutting tool 1, and the negative type is a type in which the side surface is parallel to the above-described central axis.

[0103] In the above-described embodiment, an example in which the substrate 10 contains cubic boron nitride (cBN) particles is described. However, the substrate disclosed in the present application may contain particles such as hexagonal boron nitride (hBN), rhombohedral boron nitride (rBN), and wurtzite boron nitride (wBN), for example.

[0104] In the above-described embodiment, the case where the coated cutting tool 1 is used for cutting is described. However, the coated cutting tool of the present application may also be applied to tools other than cutting tools such as excavation tools or cutting tools with cutting edges.

[0105] More effects and variation examples can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited by the specific details and representative embodiments described as above. Therefore, various changes can be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

[0106] Symbol Explanation

[0107] 1 Coated cutting tool

[0108] 2 Blade body

[0109] 3 Cutting edge part

[0110] 4 Support surface

[0111] 5 Through hole

[0112] 6 First surface

[0113] 7 Second surface

[0114] 8 Cutting edge

[0115] 10 Substrate

[0116] 20 Coating film

[0117] 21 Hard layer

[0118] 22 Metal layer

[0119] 23 Laminated part

[0120] 23a First metal nitride layer

[0121] 23b Second metal nitride layer

[0122] 24 Third metal nitride layer

[0123] 30 Substrate

[0124] 40 Bonding material

[0125] 70 Tool shank

[0126] 73 Card slot

[0127] 75 Bolt

[0128] 100 Cutting tool

Claims

1. A coated cutting tool, which has: a substrate containing a plurality of boron nitride particles, and a coating film located on the substrate, The coating film includes: a hard layer; and a metal layer other than the simple substances of Ti, Zr, V, Cr, Ta, Nb, Hf, and Al located between the substrate and the hard layer, the hard layer has one or more metal nitride layers, the metal nitride layer includes: a first metal nitride layer; a second metal nitride layer having a composition different from that of the first metal nitride layer, the hard layer has: a laminated portion including a plurality of the first metal nitride layers and a plurality of the second metal nitride layers, and the first metal nitride layers and the second metal nitride layers are alternately laminated; a third metal nitride layer located at a position farther from the substrate than the laminated portion, the thickness of the third metal nitride layer is thicker than the thicknesses of the first metal nitride layer and the second metal nitride layer, and the thickness of the third metal nitride layer is thicker than the thickness of the laminated portion.

2. The coated cutting tool according to claim 1, wherein, The metal layer contains at least one element among Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y.

3. The coated cutting tool according to claim 2, wherein, The metal layer contains 95 atomic% or more of the element.

4. The coated cutting tool according to claim 1 or 2, wherein, The metal layer contains Al and Cr in a total amount of 95 atomic% or more.

5. The coated cutting tool according to claim 1 or 2, wherein The Ti content in the metal layer is 15 atomic% or less.

6. The coated cutting tool according to claim 1 or 2, wherein The substrate has a binder phase between the boron nitride particles.

7. The coated cutting tool according to claim 1 or 2, wherein, The metal nitride layer in contact with the metal layer contains the metal contained in the metal layer.

8. The coated cutting tool according to claim 1, wherein, The thicknesses of the first metal nitride layer and the second metal nitride layer are each 50 nm or less.

9. The coated cutting tool according to claim 1 or 8, wherein the metal layer contains a first metal and a second metal, the first metal nitride layer contains nitrides of the first metal and a third metal, the second metal nitride layer contains nitrides of the first metal and the second metal.

10. The coated cutting tool according to claim 9, wherein, The first metal nitride layer contains Ti and Al, The second metal nitride layer contains Al and Cr.

11. The coated cutting tool according to claim 1 or 2, wherein the hard layer has a cubic crystal, when 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), the I(200) / the I(111) is 5.3 or more.

12. A cutting tool, which has: a rod-shaped tool shank having a groove at the end; the coated cutting tool according to any one of claims 1 to 11 located in the groove.

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