Covered tools and cutting tools

Abstract

A coated tool according to the present disclosure comprises a substrate, a first coating layer, a second coating layer, and a third coating layer. The first coating layer contains Al, Ti, Cr, and N. The second coating layer includes a first film and a second film. The first film contains Al, Ti, Cr, and N and has a Ti / Al ratio higher than that of the first coating layer. The second film contains Al, Ti, Cr, and N and has a Cr / Al ratio higher than that of the first coating layer. The third coating layer includes a third film and a fourth film. The third film contains Al, Ti, Cr, and N and has a Ti / Al ratio higher than that of the first film. The fourth film contains Al, Ti, Cr, and N and has a Cr / Al ratio higher than that of the second film.

Description

Technical Field

[0001] The present disclosure relates to a coated tool and a cutting tool.

Background Art

[0002] As a tool used for cutting operations such as turning or milling, a coated tool is known in which the surface of a substrate such as cemented carbide, cermet, or ceramics is coated with a coating layer to improve wear resistance and the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

[0004] A coated tool according to an aspect of the present disclosure includes a substrate, a first coating layer located on the substrate, a second coating layer located on the first coating layer, and a third coating layer located on the second coating layer. The first coating layer contains Al, Ti, Cr, and N. The second coating layer includes a first film and a second film. The first film contains Al, Ti, Cr, and N and has a Ti / Al ratio higher than the Ti / Al ratio in the first coating layer. The second film contains Al, Ti, Cr, and N and has a Cr / Al ratio higher than the Cr / Al ratio in the first coating layer. The third coating layer includes a third film and a fourth film. The third film contains Al, Ti, Cr, and N and has a Ti / Al ratio higher than the Ti / Al ratio in the first film. The fourth film contains Al, Ti, Cr, and N and has a Cr / Al ratio higher than the Cr / Al ratio in the second film.

Brief Description of the Drawings

[0005] [Figure 1]Figure 1 is a perspective view showing an example of a coating tool according to an embodiment. [Figure 2] Figure 2 is a side cross-sectional view showing an example of a coating tool according to the embodiment. [Figure 3] Figure 3 is a cross-sectional view showing an example of a coating layer according to the first embodiment. [Figure 4A] Figure 4A is a schematic diagram illustrating the Ti / Al ratio in the coating layer according to the first embodiment. [Figure 4B] Figure 4B is a schematic diagram illustrating the Cr / Al ratio in the coating layer according to the first embodiment. [Figure 5A] Figure 5A is a cross-sectional view showing an example of the first coating layer included in the coating layer according to the first embodiment. [Figure 5B] Figure 5B is a cross-sectional view showing an example of a second coating layer included in the coating layer according to the first embodiment. [Figure 5C] Figure 5C is a cross-sectional view showing an example of a third coating layer included in the coating layer according to the first embodiment. [Figure 6] Figure 6 is a cross-sectional view showing an example of a coating layer according to the second embodiment. [Figure 7A] Figure 7A is a schematic diagram illustrating the Ti / Al ratio in the coating layer according to the second embodiment. [Figure 7B] Figure 7B is a schematic diagram illustrating the Cr / Al ratio in the coating layer according to the second embodiment. [Figure 8] Figure 8 is a cross-sectional view showing an example of a fourth coating layer included in the coating layer according to the second embodiment. [Figure 9] Figure 9 is a schematic diagram showing an example of a film deposition apparatus for forming a coating layer on a substrate. [Figure 10] Figure 10 is a front view showing an example of a cutting tool according to an embodiment. [Modes for carrying out the invention]

[0006] The following describes in detail, with reference to the drawings, embodiments for carrying out the coating tool and cutting tool according to this disclosure (hereinafter referred to as "Embodiments"). These embodiments do not limit the coating tool and cutting tool according to this disclosure. Each embodiment can be combined as appropriate, as long as the processing content is not inconsistent. In the following embodiments, the same parts are denoted by the same reference numerals, and redundant descriptions are omitted.

[0007] In the embodiments described below, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not require strict "constant," "orthogonal," "perpendicular," or "parallel" conditions. In other words, each of the above expressions allows for deviations such as manufacturing accuracy or installation accuracy.

[0008] As tools used in cutting processes such as turning or milling, coated tools are known in which the surface of a substrate such as cemented carbide, cermet, or ceramics is coated with a coating layer to improve wear resistance and other properties.

[0009] The conventional technologies described above still have room for further improvement in terms of extending tool life.

[0010] Therefore, there is a great need for technology that can overcome the aforementioned problems and extend the lifespan of tools.

[0011] <Covered Tools> Figure 1 is a perspective view showing an example of a coating tool according to the embodiment. Figure 2 is a side cross-sectional view showing an example of a coating tool according to the embodiment. As shown in Figure 1, the coating tool 1 according to the embodiment has a tip body 2.

[0012] (Chip body 2) The chip body 2 has a hexahedron shape, for example, in which the top and bottom surfaces (the surfaces intersecting the Z-axis as shown in Figure 1) are parallelograms.

[0013] One corner of the chip body 2 functions as a cutting edge portion. The cutting edge portion has a first surface (for example, the upper surface) and a second surface (for example, the side surface) connected to the first surface. In an embodiment, the first surface functions as a "rake surface" for scooping up chips generated by cutting, and the second surface functions as a "flank surface". A cutting edge is located at at least a part of the ridge line where the first surface and the second surface intersect, and the coated tool 1 cuts the workpiece by applying such a cutting edge to the workpiece.

[0014] A through hole 5 penetrating the chip body 2 vertically is located at the central portion of the chip body 2. A screw 75 for attaching the coated tool 1 to a holder 70 described later is inserted into the through hole 5 (see FIG. 10).

[0015] As shown in FIG. 2, the chip body 2 has a substrate 10 and a coating layer 20.

[0016] (Substrate 10) The substrate 10 is formed of, for example, cemented carbide. The cemented carbide contains W (tungsten), specifically WC (tungsten carbide). The cemented carbide may contain Ni (nickel) or Co (cobalt). Specifically, the substrate 10 is made of a WC-based cemented carbide having WC particles as a hard phase component and Co as a main component of the binder phase.

[0017] The substrate 10 may be formed of cermet. The cermet contains, for example, Ti (titanium), specifically TiC (titanium carbide) or TiN (titanium nitride). The cermet may contain Ni or Co.

[0018] The substrate 10 may be formed of a cubic boron nitride (cBN) - based sintered body containing cBN particles. The substrate 10 is not limited to cBN particles and may contain particles such as hexagonal boron nitride (hBN), rhombohedral boron nitride (rBN), or wurtzite boron nitride (wBN).

[0019] The substrate 10 may be formed from ceramics. Examples of ceramics include Al2O3 (aluminum oxide). Examples of Al2O3 types include κ-Al2O3 and α-Al2O3. The ceramics may contain other elements in addition to aluminum oxide. For example, in addition to aluminum oxide, the ceramics may contain at least one of magnesium (Mg), calcium (Ca), strontium (Sr), silicon (Si), and a group 3 element of the periodic table.

[0020] (Coating layer 20) The coating layer 20 is applied to the substrate 10 for purposes such as improving the wear resistance and heat resistance of the substrate 10. In the example shown in Figure 2, the coating layer 20 covers the entire substrate 10. The coating layer 20 only needs to be located on top of the substrate 10. When the coating layer 20 is located on the first surface (in this case, the top surface) of the substrate 10, the wear resistance and heat resistance of the first surface are high. When the coating layer 20 is located on the second surface (in this case, the side surface) of the substrate 10, the wear resistance and heat resistance of the second surface are high.

[0021] (Coating layer 20A according to the first embodiment) Here, the specific configuration of the coating layer 20A according to the first embodiment will be described with reference to Figures 3, 4A, 4B, 5A, 5B, and 5C. Figure 3 is a cross-sectional view showing an example of the coating layer according to the first embodiment. Figure 4A is a schematic diagram illustrating the Ti / Al ratio in the coating layer according to the first embodiment. Figure 4B is a schematic diagram illustrating the Cr / Al ratio in the coating layer according to the first embodiment. Figure 5A is a cross-sectional view showing an example of the first coating layer included in the coating layer according to the first embodiment. Figure 5B is a cross-sectional view showing an example of the second coating layer included in the coating layer according to the first embodiment. Figure 5C is a cross-sectional view showing an example of the third coating layer included in the coating layer according to the first embodiment.

[0022] As shown in Figure 3, the coating layer 20A according to the first embodiment, as the coating layer 20, includes a first coating layer 21 located on the substrate 10, a second coating layer 22 located on the first coating layer 21, and a third coating layer 23 located on the second coating layer 22. If the chip body 2 includes an intermediate layer 11 in addition to the substrate 10 and the coating layer 20A as the coating layer 20, then, as shown in Figure 3, the intermediate layer 11 is located between the substrate 10 and the first coating layer 21. In this case, the first coating layer 21 is located on the substrate 10 via the intermediate layer 11.

[0023] (First coating layer 21) The first coating layer 21 contains Al, Ti, Cr, and N. The first coating layer 21 may also be an AlTiCrN layer containing AlTiCrN, which is a nitride of Al, Ti, and Cr. The notation "AlTiCrN" means that Al, Ti, Cr, and N are present in any proportion, and does not necessarily mean that Al, Ti, Cr, and N are present in a 1:1:1:1 ratio. The thickness of the first coating layer 21 is, for example, 500 nm or more and 1500 nm or less.

[0024] The first coating layer 21 located on the base 10 can reduce residual stress between the base 10 and the coating layers located on the first coating layer 21 (in the case of coating layer 20A, the second coating layer 22 and the third coating layer 23). In other words, the first coating layer 21 can reduce residual stress between the base 10 and the coating layer 20A. This reduces delamination or cracking between the base 10 and the coating layer 20A. In other words, it can improve the adhesion between the base 10 and the coating layer 20A. As a result, the lifespan of the coating tool 1 can be extended.

[0025] (Second coating layer 22) The second coating layer 22 includes a first film 31 and a second film 32, as shown in Figure 3. Each of the first film 31 and the second film 32 contains Al, Ti, Cr, and N. Each of the first film 31 and the second film 32 may be, for example, an AlTiCrN film containing AlTiCrN, which is a nitride of Al, Ti, and Cr. The thickness of the first film 31 is, for example, 200 nm to 400 nm. The thickness of the second film 32 is, for example, 200 nm to 400 nm.

[0026] The first film 31 has a Ti / Al ratio higher than that of the first coating layer 21. Here, the Ti / Al ratio means the ratio of the number of Ti atoms to the number of Al atoms. This makes it possible to improve the wear resistance and chipping resistance of the coating layer 20A without significantly increasing the residual stress between the substrate 10 and the coating layer located on the second coating layer 22 (the third coating layer 23 in the case of coating layer 20A). The first film 31 may also have a Cr / Al ratio lower than that of the first coating layer 21.

[0027] The second film 32 has a higher Cr / Al ratio than the first coating layer 21. Here, the Cr / Al ratio means the ratio of the number of Cr atoms to the number of Al atoms. This makes it possible to improve the lubricity and welding resistance of the coating layer 20A without significantly increasing the residual stress between the substrate 10 and the coating layer located on the second coating layer 22 (the third coating layer 23 in the case of coating layer 20A). The second film 32 may also have a lower Ti / Al ratio than the first coating layer 21.

[0028] The second coating layer 22 can improve the wear resistance and chipping resistance of the coating layer 20A, as well as the lubricity and welding resistance of the coating layer 20A, without significantly increasing the residual stress between the substrate 10 and the coating layer located on the second coating layer 22. As a result, the lifespan of the coated tool 1 can be extended.

[0029] (Third coating layer 23) The third coating layer 23 includes a third film 33 and a fourth film 34, as shown in Figure 3. Each of the third film 33 and the fourth film 34 contains Al, Ti, Cr, and N. Each of the third film 33 and the fourth film 34 may be, for example, an AlTiCrN film containing AlTiCrN, which is a nitride of Al, Ti, and Cr. The thickness of the third film 33 is, for example, 200 nm to 400 nm. The thickness of the fourth film 34 is, for example, 200 nm to 400 nm.

[0030] The third film 33 has a Ti / Al ratio higher than that of the first film 31. Here, the Ti / Al ratio means the ratio of the number of Ti atoms to the number of Al atoms. This improves the wear resistance and chipping resistance of the coating layer 20A. The third film 33 may also have a Cr / Al ratio lower than that of the first film 31.

[0031] The fourth film 34 has a higher Cr / Al ratio than the second film 32. Here, the Cr / Al ratio means the ratio of the number of Cr atoms to the number of Al atoms. This improves the lubricity and welding resistance of the coating layer 20A. The fourth film 34 may also have a lower Ti / Al ratio than the second film 32.

[0032] The third coating layer 23 can improve the wear resistance and chipping resistance of the coating layer 20A, as well as the lubricity and welding resistance of the coating layer 20A. As a result, the lifespan of the coated tool 1 can be extended.

[0033] (Example of Ti / Al ratio in coating layer 20A) As shown in Figure 4A, the Ti / Al ratio in the coating layer 20A may change continuously in the direction of the thickness of the coating layer 20A. If the Ti / Al ratio in the target region of the coating layer 20A is not constant, the average value of the Ti / Al ratio in this region may be used as the Ti / Al ratio for that region.

[0034] In the example shown in Figure 4A, the Ti / Al ratio in coating layer 20A is approximately constant in the first coating layer 21. The Ti / Al ratio in coating layer 20A is maximum in the first film 31 contained in the second coating layer 22 and in the third film 33 contained in the third coating layer 23. The Ti / Al ratio in coating layer 20A is minimum in the second film 32 contained in the second coating layer 22 and in the fourth film 34 contained in the third coating layer 23.

[0035] Here, it is not only the case that the Ti / Al ratio in the first film 31 is greater than the Ti / Al ratio in the first coating layer 21, but the maximum value of the Ti / Al ratio in the first film 31 may also be greater than the Ti / Al ratio in the first coating layer 21. It is not only the case that the Ti / Al ratio in the third film 33 is greater than the Ti / Al ratio in the first film 31, but the maximum value of the Ti / Al ratio in the third film 33 may also be greater than the maximum value of the Ti / Al ratio in the first film 31.

[0036] It is not only the case that the Ti / Al ratio in the second film 32 is smaller than the Ti / Al ratio in the first coating layer 21, but the minimum value of the Ti / Al ratio in the second film 32 may also be smaller than the Ti / Al ratio in the first coating layer 21. It is not only the case that the Ti / Al ratio in the fourth film 34 is smaller than the Ti / Al ratio in the second film 32, but the minimum value of the Ti / Al ratio in the fourth film 34 may also be smaller than the minimum value of the Ti / Al ratio in the second film 32.

[0037] (Example of Cr / Al ratio in coating layer 20A) As shown in Figure 4B, the Cr / Al ratio in the coating layer 20A may change continuously in the direction of the thickness of the coating layer 20A. If the Cr / Al ratio in the target region of the coating layer 20A is not constant, the average value of the Cr / Al ratio in this region may be used as the Cr / Al ratio for that region.

[0038] In the example shown in Figure 4B, the Cr / Al ratio in coating layer 20A is approximately constant in the first coating layer 21. The Cr / Al ratio in coating layer 20A is maximum in the second film 32 contained in the second coating layer 22 and in the fourth film 34 contained in the third coating layer 23. The Cr / Al ratio in coating layer 20A is minimum in the first film 31 contained in the second coating layer 22 and in the third film 33 contained in the third coating layer 23.

[0039] Here, it is not only the case that the Cr / Al ratio in the second film 32 is greater than the Cr / Al ratio in the first coating layer 21, but the maximum value of the Cr / Al ratio in the second film 32 may also be greater than the Cr / Al ratio in the first coating layer 21. It is not only the case that the Cr / Al ratio in the fourth film 34 is greater than the Cr / Al ratio in the second film 32, but the maximum value of the Cr / Al ratio in the fourth film 34 may also be greater than the maximum value of the Cr / Al ratio in the second film 32.

[0040] It is not only the case that the Cr / Al ratio in the first film 31 is smaller than the Cr / Al ratio in the first coating layer 21, but the minimum value of the Cr / Al ratio in the first film 31 may also be smaller than the Cr / Al ratio in the first coating layer 21. It is not only the case that the Cr / Al ratio in the third film 33 is smaller than the Cr / Al ratio in the first film 31, but the minimum value of the Cr / Al ratio in the third film 33 may also be smaller than the minimum value of the Cr / Al ratio in the first film 31.

[0041] The coating layer 20A shown is formed by sequentially laminating a first coating layer 21, a first film 31, a second film 32, a third film 33, and a fourth film 34 on a substrate 10. However, the first coating layer 21, the second film 32, the first film 31, the fourth film 34, and the third film 33 on the substrate 10 may also be laminated in that order.

[0042] (Examples of the first coating layer 21, the second coating layer 22, and the third coating layer 23) As shown in Figure 5A, the first coating layer 21 may include a region in which multiple compound layers 21a and multiple compound layers 21b are alternately stacked. Here, the Ti / Al ratio and Cr / Al ratio in compound layer 21a are different from the Ti / Al ratio and Cr / Al ratio in compound layer 21b, respectively. For example, the Ti / Al ratio in compound layer 21a is greater than the Ti / Al ratio in compound layer 21b, and the Cr / Al ratio in compound layer 21b is greater than the Cr / Al ratio in compound layer 21a. The average thickness of each of the compound layers 21a and compound layer 21b is between 1 nm and 10 nm.

[0043] In this case, the hardness of the first coating layer 21 can be improved. This improves the strength of the first coating layer 21. As a result, the lifespan of the coating tool 1 can be extended.

[0044] As shown in Figure 5B, the first film 31 contained in the second coating layer 22 may include regions in which multiple compound layers 31a and multiple compound layers 31b are alternately stacked. Here, the Ti / Al ratio and Cr / Al ratio in compound layer 31a are different from the Ti / Al ratio and Cr / Al ratio in compound layer 31b, respectively. For example, the Ti / Al ratio in compound layer 31a is greater than the Ti / Al ratio in compound layer 31b, and the Cr / Al ratio in compound layer 31b is greater than the Cr / Al ratio in compound layer 31a. The average thickness of each of the compound layers 31a and compound layer 31b is between 1 nm and 10 nm.

[0045] In this case, the hardness of the first film 31 and, accordingly, the hardness of the second coating layer 22 can be improved. This allows for an improvement in the strength of the first film 31 and, accordingly, the strength of the second coating layer 22. As a result, the lifespan of the coating tool 1 can be extended.

[0046] As shown in Figure 5B, the second film 32 contained in the second coating layer 22 may include a region in which multiple compound layers 32a and multiple compound layers 32b are alternately stacked. Here, the Ti / Al ratio and Cr / Al ratio in compound layer 32a are different from the Ti / Al ratio and Cr / Al ratio in compound layer 32b, respectively. For example, the Cr / Al ratio in compound layer 32a is greater than the Cr / Al ratio in compound layer 32b, and the Ti / Al ratio in compound layer 32b is greater than the Ti / Al ratio in compound layer 32a. The average thickness of each of the compound layers 32a and compound layer 32b is between 1 nm and 10 nm.

[0047] In this case, the hardness of the second film 32 and, accordingly, the hardness of the second coating layer 22 can be improved. This allows for an improvement in the strength of the second film 32 and, accordingly, the strength of the second coating layer 22. As a result, the lifespan of the coating tool 1 can be extended.

[0048] As shown in Figure 5C, the third film 33 contained in the third coating layer 23 may include a region in which multiple compound layers 33a and multiple compound layers 33b are alternately stacked. Here, the Ti / Al ratio and Cr / Al ratio in compound layer 33a are different from the Ti / Al ratio and Cr / Al ratio in compound layer 33b, respectively. For example, the Ti / Al ratio in compound layer 33a is greater than the Ti / Al ratio in compound layer 33b, and the Cr / Al ratio in compound layer 33b is greater than the Cr / Al ratio in compound layer 33a. The average thickness of each compound layer 33a and compound layer 33b is between 1 nm and 10 nm.

[0049] In this case, the hardness of the third film 33 and, accordingly, the hardness of the third coating layer 23 can be improved. This allows for an improvement in the strength of the third film 33 and, accordingly, the strength of the third coating layer 23. As a result, the lifespan of the coating tool 1 can be extended.

[0050] As shown in Figure 5C, the fourth film 34 contained in the third coating layer 23 may include a region in which multiple compound layers 34a and multiple compound layers 34b are alternately stacked. Here, the Ti / Al ratio and Cr / Al ratio in compound layer 34a are different from the Ti / Al ratio and Cr / Al ratio in compound layer 34b, respectively. For example, the Cr / Al ratio in compound layer 34a is greater than the Cr / Al ratio in compound layer 34b, and the Ti / Al ratio in compound layer 34b is greater than the Ti / Al ratio in compound layer 34a. The average thickness of each compound layer 34a and compound layer 34b is between 1 nm and 10 nm.

[0051] In this case, the hardness of the fourth film 34 and, accordingly, the hardness of the third coating layer 23 can be improved. This allows for an improvement in the strength of the fourth film 34 and, accordingly, the strength of the third coating layer 23. As a result, the lifespan of the coating tool 1 can be extended.

[0052] The proportion of elements in the coating layer or film contained in the coating layer 20A can be identified, for example, by analysis based on X-ray photoelectron spectroscopy (XPS) or by analysis using an energy-dispersive X-ray spectrometer (EDS) attached to a scanning transmission electron microscope (STEM). The presence of multiple alternately stacked compound layers in the film contained in the coating layer 20A can be confirmed by bright-field images or high-angle scattered annular dark-field images obtained by a scanning transmission electron microscope (STEM), or by analysis using an energy-dispersive X-ray spectrometer (EDS).

[0053] (Intermediate layer 11) As shown in Figure 3, an intermediate layer 11 may be located between the substrate 10 and the coating layer 20A. Specifically, the intermediate layer 11 is in contact with the upper surface of the substrate 10 on one side (here, the lower surface) and in contact with the lower surface of the coating layer 20A (for example, the first coating layer 21) on the other side (here, the upper surface).

[0054] The intermediate layer 11 has higher adhesion to the substrate 10 compared to the coating layer 20A. Examples of metal elements having such properties include Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Y, and Ti. The intermediate layer 11 contains at least one of the above metal elements. For example, the intermediate layer 11 may contain Ti. Although Si is a metalloid element, in this specification, metalloid elements are also included in the definition of metal elements.

[0055] If the intermediate layer 11 contains Ti, the Ti content in the intermediate layer 11 may be 1.5 atomic percent or more. For example, the Ti content in the intermediate layer 11 may be 2 atomic percent or more.

[0056] The intermediate layer 11 may contain components other than the above-mentioned metal elements (Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Y, and Ti). However, from the viewpoint of adhesion to the substrate 10, the intermediate layer 11 may contain at least 95 atomic percent of the above-mentioned metal elements in total. The intermediate layer 11 may contain 98 atomic percent or more of the above-mentioned metal elements in total. The proportion of metal components in the intermediate layer 11 can be determined, for example, by analysis using an energy-dispersive X-ray spectrometer (EDS) attached to a scanning transmission electron microscope (STEM).

[0057] In this way, by providing an intermediate layer 11, which has a higher wettability with the substrate 10 compared to the coating layer 20A, between the substrate 10 and the coating layer 20A, the adhesion between the substrate 10 and the coating layer 20A can be improved. Since the intermediate layer 11 also has high adhesion with the coating layer 20A, the coating layer 20A is less likely to peel off from the intermediate layer 11.

[0058] The thickness of the intermediate layer 11 may be, for example, 0.1 nm or more and less than 20 nm.

[0059] (Coating layer 20B according to the second embodiment) Next, the specific configuration of the coating layer 20B according to the second embodiment will be described with reference to Figures 6, 7A, 7B, and 8. Figure 6 is a cross-sectional view showing an example of the coating layer according to the second embodiment. Figure 7A is a schematic diagram illustrating the Ti / Al ratio in the coating layer according to the second embodiment. Figure 7B is a schematic diagram illustrating the Cr / Al ratio in the coating layer according to the second embodiment. Figure 8 is a cross-sectional view showing an example of a fourth coating layer included in the coating layer according to the second embodiment.

[0060] As shown in Figure 6, the coating layer 20B according to the second embodiment differs from the coating layer 20A according to the first embodiment in that the coating layer 20B according to the second embodiment further includes a fourth coating layer 24 located on the third coating layer 23. The description of the configuration of the coating layer 20B according to the second embodiment, which is the same as the configuration of the coating layer 20A according to the first embodiment, will be omitted.

[0061] (Fourth coating layer 24) The fourth coating layer 24 includes a fifth film 35 and a sixth film 36, as shown in Figure 6.

[0062] The fifth film 35 contains Al, Ti, and N. The fifth film 35 may be, for example, an AlTiN film containing AlTiN, which is a nitride of Al and Ti. The notation "AlTiN" means that Al, Ti, and N are present in any proportion, and does not necessarily mean that Al, Ti, and N are present in a 1:1:1 ratio. The fifth film 35 may further contain Cr. In this case, the fifth film 35 may be, for example, an AlTiCrN film containing AlTiCrN, which is a nitride of Al, Ti, and Cr. The thickness of the fifth film 35 is, for example, 200 nm or more and 400 nm or less.

[0063] The sixth film 36 contains Al, Cr, and N. The sixth film 36 may be, for example, an AlCrN film containing AlCrN, which is a nitride of Al and Cr. The notation "AlCrN" means that Al, Cr, and N are present in any proportion, and does not necessarily mean that Al, Cr, and N are present in a 1:1:1 ratio. The sixth film 36 may further contain Ti. In this case, the sixth film 36 may be, for example, an AlTiCrN film containing AlTiCrN, which is a nitride of Al, Ti, and Cr. The thickness of the sixth film 36 is, for example, 200 nm or more and 400 nm or less.

[0064] The fifth film 35 has a Ti / Al ratio higher than that of the third film 33. Here, the Ti / Al ratio means the ratio of the number of Ti atoms to the number of Al atoms. This further improves the wear resistance and chipping resistance of the coating layer 20B. The fifth film 35 may also have a Cr / Al ratio lower than that of the third film 33.

[0065] The sixth film 36 has a higher Cr / Al ratio than the fourth film 34. Here, the Cr / Al ratio means the ratio of the number of Cr atoms to the number of Al atoms. This further improves the lubricity and welding resistance of the coating layer 20B. The sixth film 36 may also have a lower Ti / Al ratio than the fourth film 34.

[0066] The fourth coating layer 24 further improves the wear resistance and chipping resistance of coating layer 20B, as well as the lubricity and welding resistance of coating layer 20A. As a result, the lifespan of the coated tool 1 can be further extended.

[0067] In the coating layer 20B, the third coating layer 23 acts in such a way as not to significantly increase the residual stress between the substrate 10 and the fourth coating layer 24, which is located on top of the third coating layer 23.

[0068] The Ti / Al ratio in the fifth film 35 may be between 1 and 1.5. When the Ti / Al ratio in the fifth film 35 is 1 or greater, the wear resistance and chipping resistance of the coating layer 20B can be further improved. When the Ti / Al ratio in the fifth film 35 is 1.5 or less, the residual stress between the substrate 10 and the coating layer 20B can be prevented from increasing significantly. This reduces delamination or cracking between the substrate 10 and the coating layer 20B. As a result, the lifespan of the coated tool 1 can be further extended.

[0069] The Cr / Al ratio in the sixth film 36 may be between 1 and 1.5. When the Cr / Al ratio in the sixth film 36 is 1 or greater, the lubricity and welding resistance of the coating layer 20B can be further improved. When the Cr / Al ratio in the sixth film 36 is 1.5 or less, the residual stress between the substrate 10 and the coating layer 20B can not be significantly increased. This reduces delamination or cracking between the substrate 10 and the coating layer 20B. As a result, the lifespan of the coated tool 1 can be further extended.

[0070] (Example of Ti / Al ratio in coating layer 20B) As shown in Figure 7A, the Ti / Al ratio in the coating layer 20B may change continuously in the direction of the thickness of the coating layer 20B. If the Ti / Al ratio in the target region of the coating layer 20B is not constant, the average value of the Ti / Al ratio in this region may be used as the Ti / Al ratio for that region.

[0071] In the example shown in Figure 7A, the Ti / Al ratio in coating layer 20B is also maximum in the fifth film 35 contained within the fourth coating layer 24. The Ti / Al ratio in coating layer 20B is also minimum in the sixth film 36 contained within the fourth coating layer 24.

[0072] Here, the maximum value of the Ti / Al ratio in the fifth film 35 is greater than the maximum value of the Ti / Al ratio in the third film 33. On the other hand, the minimum value of the Ti / Al ratio in the sixth film 36 is smaller than the minimum value of the Ti / Al ratio in the fourth film 34. The minimum value of the Ti / Al ratio in the sixth film 36 is, for example, substantially zero.

[0073] (Example of Cr / Al ratio in coating layer 20B) As shown in Figure 7B, the Cr / Al ratio in the coating layer 20B may change continuously in the direction of the thickness of the coating layer 20B. If the Cr / Al ratio in the target region of the coating layer 20B is not constant, the average value of the Cr / Al ratio in this region may be used as the Cr / Al ratio for that region.

[0074] In the example shown in Figure 7B, the Cr / Al ratio in coating layer 20B is also maximum in the sixth film 36 contained in the fourth coating layer 24. The Cr / Al ratio in coating layer 20B is also minimum in the fifth film 35 contained in the fourth coating layer 24.

[0075] Here, the maximum value of the Cr / Al ratio in the sixth membrane 36 is greater than the maximum value of the Cr / Al ratio in the fourth membrane 34. On the other hand, the minimum value of the Cr / Al ratio in the fifth membrane 35 is smaller than the minimum value of the Cr / Al ratio in the third membrane 33. The minimum value of the Cr / Al ratio in the fifth membrane 35 is, for example, substantially zero.

[0076] The coated layer 20B shown is formed by sequentially laminating a first coating layer 21, a first film 31, a second film 32, a third film 33, a fourth film 34, a fifth film 35, and a sixth film 36 on a substrate 10. However, the first coating layer 21, the second film 32, the first film 31, the fourth film 34, the third film 33, the sixth film 36, and the fifth film 35 on the substrate 10 may also be laminated in that order.

[0077] (Example of the fourth coating layer 24) As shown in Figure 8, the fifth film 35 contained in the fourth coating layer 24 may include a region in which multiple compound layers 35a and multiple compound layers 35b are alternately stacked. Here, the Ti / Al ratio in compound layer 35a is different from the Ti / Al ratio in compound layer 35b. For example, the Ti / Al ratio in compound layer 35a is greater than the Ti / Al ratio in compound layer 35b. The average thickness of each of the compound layers 35a and compound layer 35b is between 1 nm and 10 nm.

[0078] In this case, the hardness of the fifth film 35 and, accordingly, the hardness of the fourth coating layer 24 can be improved. In particular, the hardness of the fourth coating layer 24 at high temperatures can be improved. This allows for an improvement in the strength of the fifth film 35 and, accordingly, the strength of the fourth coating layer 24. In particular, the wear resistance of the fourth coating layer 24 can be improved. As a result, the lifespan of the coated tool 1 can be further extended.

[0079] As shown in Figure 8, the sixth film 36 contained in the fourth coating layer 24 may include a region in which multiple compound layers 36a and multiple compound layers 36b are alternately stacked. Here, the Cr / Al ratio in compound layer 36a is different from the Cr / Al ratio in compound layer 36b. For example, the Cr / Al ratio in compound layer 36a is greater than the Cr / Al ratio in compound layer 36b. The average thickness of each of the compound layers 36a and compound layer 36b is between 1 nm and 10 nm.

[0080] In this case, the hardness of the sixth film 36 and, accordingly, the hardness of the fourth coating layer 24 can be improved. In particular, the hardness of the fourth coating layer 24 at high temperatures can be improved. This allows for an improvement in the strength of the sixth film 36 and, accordingly, the strength of the fourth coating layer 24. In particular, the wear resistance of the fourth coating layer 24 can be improved. As a result, the lifespan of the coated tool 1 can be further extended.

[0081] <Method for manufacturing covered tools> Next, with reference to Figure 9, an example of a method for manufacturing the coated tool 1 according to the embodiment will be described. Figure 9 is a schematic diagram showing an example of a film deposition apparatus for forming a coating layer on a substrate. The method for manufacturing the coated tool 1 is not limited to the method shown below.

[0082] First, a substrate 10 having the shape of a coating tool 1 is fabricated using a conventionally known method. Next, a coating layer 20 is formed on the surface of the substrate 10. As a method for forming the coating layer 20, for example, a physical vapor deposition (PVD) method such as ion plating or sputtering can be used. For example, when fabricating the coating layer 20 by ion plating, an arc ion plating apparatus (hereinafter referred to as AIP apparatus) 1000 as shown in Figure 9 can be used.

[0083] The AIP apparatus 1000 shown in Figure 9 introduces a gas such as N2 or Ar into a vacuum chamber 101 through a gas inlet 102, and applies a high voltage between the cathode electrode 103 and anode electrode 104 located in the AIP apparatus 1000 to generate a gas plasma. This plasma evaporates and ionizes the desired metal or ceramic from the target 105, generating high-energy ions of the metal or ceramic. These ionized metal or ceramic is then deposited onto the surface of the substrate 10, which serves as the sample, to form a coating layer 20 on the surface of the substrate 10.

[0084] As shown in Figure 9, multiple base units 10 may be set on a tower 107 and placed on a sample support stand 106. Multiple (two sets in the figure) sample support stands 106 may be placed on a table not shown. Furthermore, as shown in Figure 9, a heater 108 for heating the base units 10, a gas outlet 109 for discharging gas to the outside of the system, and a bias power supply 110 for applying a bias voltage to the base units 10 are provided.

[0085] As target 105, for example, a metal target containing metallic aluminum (Al), metallic titanium (Ti), and metallic chromium (Cr) independently, an alloy target formed by combining these, or a mixed target consisting of nitride powder or sintered body of these can be used. For example, as target 105, a first alloy target formed by combining Al and Ti and a second alloy target formed by combining Al and Cr can be used.

[0086] Then, using target 105, the metal source is evaporated by arc discharge or glow discharge, ionizing the metal in the metal source and simultaneously reacting it with nitrogen (N2) gas from the nitrogen source, thereby depositing a coating layer 20 on the surface of substrate 10.

[0087] At that time, the sample support stand 106 is controlled so that the distance from the position of the target 105 to the position of the base 10 is 160 mm or more, for example, 260 mm or more. A large number of highly directional magnetic field lines are generated from the center of the surface of the target 105 toward the base 10, so that the magnetic flux density near the base 10 is 0.2 to 0.8 mT (millitesla).

[0088] Nitrogen gas may be introduced as a reaction gas into the AIP apparatus 1000 to maintain an atmospheric pressure of 2 to 10 Pa. The temperature of the substrate 10 is maintained at 300 to 500°C. Furthermore, a bias voltage of -50 to -200 V is applied to the substrate 10 to generate an arc discharge of 30 to 200 A between the target 105 (cathode electrode 103) and the anode electrode 104. During this time, metal is deposited onto the substrate 10 while it is rotating on its own axis and on its orbit.

[0089] Here, when stacking each coating layer in the coating layer 20 onto the substrate 10, the current value of the arc discharge generated between the target 105, which serves as the cathode electrode 103, and the anode electrode 104 is controlled. For example, the current value of the arc discharge generated between the first alloy target, which is a composite of Al and Ti, or the second alloy target, which is a composite of Al and Cr, and the anode electrode 104 is controlled.

[0090] For example, in order to increase (decrease) the Ti / Al ratio in the coating layer or film contained in the coating layer 20, the current value of the arc discharge generated between the first alloy target, which is a composite of Al and Ti as the cathode electrode 103, and the anode electrode 104 is increased (or decreased).

[0091] For example, to increase (decrease) the Cr / Al ratio in the coating layer or film contained in the coating layer 20, the current value of the arc discharge generated between the second alloy target, which is a composite of Al and Cr as the cathode electrode 103, and the anode electrode 104 is increased (or decreased).

[0092] As a method for controlling the magnetic flux density near the base 10, for example, the magnetic field can be controlled by installing an electromagnetic coil or permanent magnet, which is a magnetic field source, around the target 105, by placing a permanent magnet inside the AIP device 1000, for example, in the center, or by adjusting the position of adjacent targets 105.

[0093] The magnetic force is calculated by measuring the magnetic flux density at the base body 10 using a magnetic flux densimeter. The magnetic flux density is expressed in units of mT (millitesla). Here, the distance from the position of the target 105 to the position of the base body 10 represents the distance measured at the position where the base body 10 is closest to the target 105, and the distance at which the base body 10 is furthest from the target 105.

[0094] During film formation, the period at which the substrate 10 approaches the target 105 most closely at each position of the substrate 10 as shown in Figure 9 is defined as the sample rotation speed. By adjusting the rotation speed, the period of the difference in composition between heavy metals and light metals in the thickness direction of the coating layer 20 can be adjusted. Specifically, the rotation speed of the substrate 10 and the sample support 106 may be adjusted to have a period of 2 to 20 rpm (revolutions per minute).

[0095] During film formation, the tower 107 may rotate while each of the sample support stands 106 on which the substrate 10 is placed rotates, and the table may be rotated so that multiple sample support stands 106 revolve. By adjusting the timing of these revolves, the thickness of each compound layer constituting the first coating layer 21, the second coating layer 22 (first film 31 and second film 32), the third coating layer 23 (third film 33 and fourth film 34), and the fourth coating layer 24 (fifth film 35 and sixth film 36) can be controlled.

[0096] By applying a pulsed bias voltage, the time or distance over which metal ions travel from the target 105 to the substrate 10 can be adjusted. This also allows for differences in the composition of heavy metal and light metal components during film formation.

[0097] For example, if the substrate 10 is positioned so that it approaches and faces the target 105, heavy metal components from the target 105 will fly in a straight line to the substrate 10, resulting in more heavy metals accumulating on the substrate 10 than light metals. On the other hand, if the substrate 10 is positioned so that it is far from the target 105 and does not face it, light metal components will wrap around and accumulate on the substrate 10, so the amount of heavy metal components deposited is expected to decrease. In this case, by increasing the distance from the position of the target 105 to the position of the substrate 10 and maintaining a certain magnetic flux density near the substrate 10, the wrapping of light metal components is promoted, and the compositional difference between heavy metal components and light metal components is expected to increase.

[0098] <Cutting tools> Next, the configuration of the cutting tool equipped with the coating tool 1 described above will be explained with reference to Figure 10. Figure 10 is a front view showing an example of a cutting tool according to the embodiment.

[0099] As shown in Figure 10, the cutting tool 100 according to this embodiment comprises a coating tool 1 and a holder 70 for fixing the coating tool 1.

[0100] The holder 70 is a rod-shaped member extending from the first end (upper end in Figure 10) to the second end (lower end in Figure 10). The holder 70 is made of, for example, steel or cast iron. In particular, steel with high toughness may be used among these members.

[0101] The holder 70 has a pocket 73 at the first end. The pocket 73 is the part into which the coated tool 1 is mounted, and has a seating surface that intersects with the rotational direction of the workpiece, and a restraining side surface that is inclined with respect to the seating surface. The seating surface is provided with a screw hole into which a screw 75, which will be described later, is screwed.

[0102] The coating tool 1 is located in the pocket 73 of the holder 70 and is attached to the holder 70 by a screw 75. Specifically, the screw 75 is inserted into the through hole 5 of the coating tool 1, and the tip of the screw 75 is inserted into the screw hole formed in the seating surface of the pocket 73, and the screwed parts are screwed together. In this way, the coating tool 1 is attached to the holder 70 such that the cutting edge portion 3 protrudes outward from the holder 70.

[0103] In the embodiments, cutting tools used in so-called turning operations are illustrated. Examples of turning operations include internal diameter machining, external diameter machining, and grooving operations. The cutting tools are not limited to those used in turning operations. For example, a coated tool 1 may be used as a cutting tool for milling operations. Examples of cutting tools used in milling operations include milling cutters such as flat milling cutters, face milling cutters, side milling cutters, and groove milling cutters, and end mills such as single-flute end mills, multi-flute end mills, tapered end mills, and ball end mills. [Examples]

[0104] The embodiments of this disclosure will be described below in detail. This disclosure is not limited to the embodiments shown below.

[0105] A coated tool according to the embodiment was fabricated by forming a coating layer on a substrate made of WC-based cemented carbide using an AIP apparatus as shown in Figure 9. A first alloy target composed of Al and Ti, and a second alloy target composed of Al and Cr were used as targets. The coating layer was deposited on the substrate by reacting metal ions generated from the first or second alloy target with nitrogen gas.

[0106] Here, while the substrate is rotated and revolves and a coating layer is laminated onto the substrate, the current value of the arc discharge generated between the first or second alloy target as the cathode electrode and the anode electrode was controlled as follows.

[0107] First, the current value of the arc discharge generated between the first alloy target and the anode electrode was set to 200A, and the current value of the arc discharge generated between the second alloy target and the anode electrode was also set to 200A, thereby laminating the first coating layer onto the substrate.

[0108] Next, the current value of the arc discharge generated between the first alloy target and the anode electrode was set to 100A, and the current value of the arc discharge generated between the second alloy target and the anode electrode was set to 50A, thereby laminating the first film contained in the second coating layer onto the first coating layer.

[0109] Next, the current value of the arc discharge generated between the first metal target and the anode electrode was set to 50A, and the current value of the arc discharge generated between the second metal target and the anode electrode was set to 100A, thereby laminating the second film contained in the second coating layer onto the first film.

[0110] Next, the current value of the arc discharge generated between the first alloy target and the anode electrode was set to 120A, and the current value of the arc discharge generated between the second alloy target and the anode electrode was set to 30A, thereby laminating the third film contained in the third coating layer onto the second film.

[0111] Next, the current value of the arc discharge generated between the first alloy target and the anode electrode was set to 30A, and the current value of the arc discharge generated between the second alloy target and the anode electrode was set to 120A, thereby laminating the fourth film contained in the third coating layer onto the third film.

[0112] Next, the current value of the arc discharge generated between the first alloy target and the anode electrode was set to 150A, and the current value of the arc discharge generated between the second alloy target and the anode electrode was set to 0A, thereby laminating the fifth film contained in the fourth coating layer onto the fourth film.

[0113] Finally, by setting the current value of the arc discharge generated between the first alloy target and the anode electrode to 0A, and the current value of the arc discharge generated between the second alloy target and the anode electrode to 150A, the sixth film contained in the third coating layer was laminated on top of the fifth film.

[0114] The elements contained in the coating layer or film deposited on the substrate were analyzed using X-ray photoelectron spectroscopy (XPS) for the coated tools prepared in this manner.

[0115] It was confirmed that each of the first coating layer, the first and second films contained in the second coating layer, and the third and fourth films contained in the third coating layer each contain Al, Ti, Cr, and N. It was confirmed that the fifth film contained in the fourth coating layer contains Al, Ti, and N. It was confirmed that the sixth film contained in the fourth coating layer contains Al, Cr, and N.

[0116] It was confirmed that the Ti / Al ratio in the first coating layer, the first film, the second film, the third film, the fourth film, the fifth film, and the sixth film changes continuously with respect to the distance from the substrate surface in the direction of the thickness of the coating layer or film, i.e., in the direction perpendicular to the substrate surface. It was confirmed that the Cr / Al ratio in the first coating layer, the first film, the second film, the third film, the fourth film, the fifth film, and the sixth film changes continuously with respect to the distance from the substrate surface in the direction of the thickness of the coating layer or film, i.e., in the direction perpendicular to the substrate surface.

[0117] It was confirmed that the Ti / Al ratio (maximum value 0.8) in the first film was higher than the Ti / Al ratio (0.6) in the first coating layer. It was confirmed that the Cr / Al ratio (maximum value 0.8) in the second film was higher than the Cr / Al ratio (0.6) in the first coating layer. It was confirmed that the Ti / Al ratio (maximum value 1) in the third film was higher than the Ti / Al ratio (maximum value 0.8) in the first film. It was confirmed that the Cr / Al ratio (maximum value 1) in the fourth film was higher than the Cr / Al ratio (maximum value 0.8) in the second film. It was confirmed that the Ti / Al ratio (maximum value 1.4) in the fifth film was higher than the Ti / Al ratio (maximum value 1) in the third film. It was confirmed that the Cr / Al ratio (maximum value 1.2) in the sixth film was higher than the Cr / Al ratio (maximum value 1) in the fourth film.

[0118] Elemental analysis of the fifth and sixth films was performed using energy-dispersive X-ray spectroscopy (EDS). Bright-field and high-angle scattered annular dark-field images were obtained for the fifth and sixth films using scanning transmission electron microscopy (STEM).

[0119] It was confirmed that the fifth film includes a region in which multiple first compound layers and multiple second compound layers are alternately stacked, and that the sixth film includes a region in which multiple third compound layers and multiple fourth compound layers are alternately stacked. It was also confirmed that the Ti / Al ratio in the first compound layer is different from the Ti / Al ratio in the second compound layer, and that the Cr / Al ratio in the third compound layer is different from the Cr / Al ratio in the fourth compound layer.

[0120] <Cutting Test> Cutting tests were conducted on the coated tools according to the examples and on conventional coated tools as comparative examples (Conventional Product 1, Conventional Product 2, and Conventional Product 3). The test conditions for the cutting tests were as follows. A carbide material for drilling (model number: 2ZDK060-HP-OH (internal lubrication type) φ6mm) was used as the substrate, and the cutting tests were conducted under the following conditions. (1) Cutting method: Drilling (2) Work material: S50C (3) Cutting speed Vc: 100m / min (4) Feed rate per revolution f: 0.13 mm / rev (5) Axial cutting depth H: 12 mm (6) Processing form: Wet (7) Evaluation method: Drilling was performed on the substrate under the above conditions, and the maximum wear amount (mm) of the cutting edge of the coated tool was measured relative to the number of holes formed in the workpiece. The maximum wear amount of the cutting edge was defined as the maximum depth from the surface of the relief face of the cutting edge to the part where wear was observed.

[0121] Table 1 shows the maximum wear of the cutting edge of the coated tool according to the embodiment and conventional products (conventional product 1, conventional product 2, conventional product 3) in relation to the number of holes formed in the workpiece.

[0122] [Table 1]

[0123] As shown in Table 1, the maximum wear amount of the cutting edge of the coated tool according to the embodiment, relative to the number of holes formed in the workpiece, is smaller than the maximum wear amount of the cutting edge of the coated tool according to the conventional products (conventional product 1, conventional product 2, conventional product 3), relative to the same number of holes formed in the workpiece. Therefore, when comparing the coated tool according to the embodiment with the conventional products (conventional product 1, conventional product 2, conventional product 3), it was confirmed that the coated tool according to the embodiment can improve the wear resistance of the coated tool.

[0124] In the case of the conventional coating tool (Product 1), significant chipping occurred at the corners of the coating tool when the number of holes reached 616. On the other hand, no significant chipping occurred in the coating tool according to the embodiment. Therefore, it was confirmed that the coating tool according to the embodiment can maintain its chipping resistance.

[0125] As described above, the coating tool according to the embodiment (for example, coating tool 1) comprises a substrate (for example, substrate 10), a first coating layer located on the substrate (for example, first coating layer 21), a second coating layer located on the first coating layer (for example, second coating layer 22), and a third coating layer located on the second coating layer (for example, third coating layer 23). The first coating layer contains Al, Ti, Cr, and N. The second coating layer includes a first film (for example, first film 31) and a second film (for example, second film 32). The first film contains Al, Ti, Cr, and N and has a Ti / Al ratio higher than the Ti / Al ratio in the first coating layer. The second film contains Al, Ti, Cr, and N and has a Cr / Al ratio higher than the Cr / Al ratio in the first coating layer. The third coating layer includes a third film (for example, a third film 33) and a fourth film (for example, a fourth film 34). The third film contains Al, Ti, Cr, and N, and has a Ti / Al ratio higher than that of the first film. The fourth film contains Al, Ti, Cr, and N, and has a Cr / Al ratio higher than that of the second film.

[0126] Therefore, according to the coating tool of this embodiment, the life of the tool can be extended.

[0127] The shape of the coating tool 1 shown in Figure 1 is merely an example and does not limit the shape of the coating tool according to this disclosure. The coating tool according to this disclosure may, for example, have a rod-shaped body having a rotating shaft and extending from a first end to a second end, a cutting edge located at the first end of the body, and a groove extending spirally from the cutting edge toward the second end of the body.

[0128] <Note> Note (1): Substrate and, A first coating layer located on the substrate, A second coating layer located on the aforementioned first coating layer, A third coating layer located on top of the second coating layer and Equipped with, The first coating layer contains Al, Ti, Cr, and N. The second coating layer provided is A first film containing Al, Ti, Cr, and N, having a Ti / Al ratio higher than that of the first coating layer, A second film containing Al, Ti, Cr, and N, having a Cr / Al ratio higher than that of the first coating layer, Includes, The third coating layer is A third film containing Al, Ti, Cr, and N, having a Ti / Al ratio higher than that of the first film, A fourth film containing Al, Ti, Cr, and N, having a Cr / Al ratio higher than that of the second film, including, Covering tools. Note (2): The maximum value of the Ti / Al ratio in the third film is greater than the maximum value of the Ti / Al ratio in the first film. The covering tool described in Appendix (1). Note (3): The minimum value of the Ti / Al ratio in the fourth film is smaller than the minimum value of the Ti / Al ratio in the second film. The covering tool described in Appendix (1) or (2). Note (4): A fourth coating layer located on top of the third coating layer. Furthermore, The fourth coating layer is A fifth film containing Al, Ti, and N, having a Ti / Al ratio higher than that of the third film, A sixth film containing Al, Cr, and N, having a Cr / Al ratio higher than that of the fourth film, including, The covering tool described in any one of the appendices (1) to (3). Note (5): The maximum value of the Ti / Al ratio in the fifth film and the maximum value of the Cr / Al ratio in the sixth film are each between 1 and 1.5. The covering tools described in Appendix (4). Note (6): The fifth film includes a region in which a plurality of first compound layers and a plurality of second compound layers are alternately stacked, The sixth film includes a region in which a plurality of third compound layers and a plurality of fourth compound layers are alternately stacked, The Ti / Al ratio in the first compound layer differs from the Ti / Al ratio in the second compound layer. The Cr / Al ratio in the third compound layer is different from the Cr / Al ratio in the fourth compound layer. The covering tools described in Appendix (4) or (5). Note (7): The Ti / Al ratio in the first compound layer is greater than the Ti / Al ratio in the second compound layer. The Cr / Al ratio in the third compound layer is greater than the Cr / Al ratio in the fourth compound layer. The covering tools described in Appendix (6). Note (8): A rod-shaped holder having a pocket at the end, The covering tool located within the aforementioned pocket, and one of the covering tools described in any one of the appendices (1) to (7) A cutting tool having [a certain characteristic].

[0129] Further effects and / or modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of symbols]

[0130] 1. Covering Tools 2. Chip body 3. Cutting edge 5 Through hole 10 Base 11. Middle Class 20, 20A, 20B coating layer 21 First coating layer 22 Second coating layer 23 Third coating layer 24. Fourth coating layer 31 The first membrane 32 The second membrane 33 The third membrane 34 The fourth membrane 35 The fifth membrane 36 The sixth membrane 21a, 21b, 31a, 31b, 32a, 32b, 33a, 33b, 34a, 34b, 35a, 35b, 36a, 36b Compound layer 70 Holder 73 pockets 75 screws 100 cutting tools 101 Vacuum Chamber 102 Gas inlet 103 Cathode electrode 104 Anode electrode 105 Target 106 Sample support stand 107 Tower 108 Heater 109 Gas outlet 110 Bias Power Supply 1000 AIP devices

Claims

1. Substrate and, A first coating layer located on the substrate, A second coating layer located on the first coating layer, A third coating layer located on top of the second coating layer and Equipped with, The aforementioned first coating layer contains Al, Ti, Cr, and N. The second coating layer is A first film containing Al, Ti, Cr, and N, having a Ti / Al ratio higher than that of the first coating layer, A second film containing Al, Ti, Cr, and N, having a Cr / Al ratio higher than that of the first coating layer, and Includes, The third coating layer is A third film containing Al, Ti, Cr, and N, having a Ti / Al ratio higher than that of the first film, A fourth film containing Al, Ti, Cr, and N, having a Cr / Al ratio higher than that of the second film, and including, Covering tools.

2. The maximum value of the Ti / Al ratio in the third film is greater than the maximum value of the Ti / Al ratio in the first film. The covering tool according to claim 1.

3. The minimum value of the Ti / Al ratio in the fourth film is smaller than the minimum value of the Ti / Al ratio in the second film. The covering tool according to claim 1.

4. A fourth coating layer located on top of the third coating layer. Furthermore, The fourth coating layer is A fifth film containing Al, Ti, and N, having a Ti / Al ratio higher than that of the third film, A sixth film containing Al, Cr, and N, having a Cr / Al ratio higher than that of the fourth film, and including, The covering tool according to claim 1.

5. The maximum value of the Ti / Al ratio in the fifth film and the maximum value of the Cr / Al ratio in the sixth film are each 1 or more and 1.5 or less. The covering tool according to claim 4.

6. The fifth film includes a region in which a plurality of first compound layers and a plurality of second compound layers are alternately stacked, The sixth film includes a region in which a plurality of third compound layers and a plurality of fourth compound layers are alternately stacked, The Ti / Al ratio in the first compound layer differs from the Ti / Al ratio in the second compound layer. The Cr / Al ratio in the third compound layer is different from the Cr / Al ratio in the fourth compound layer. The covering tool according to claim 4.

7. The Ti / Al ratio in the first compound layer is greater than the Ti / Al ratio in the second compound layer. The Cr / Al ratio in the third compound layer is greater than the Cr / Al ratio in the fourth compound layer. The covering tool according to claim 6.

8. A rod-shaped holder having a pocket at the end, A covering tool according to any one of claims 1 to 7, located within the aforementioned pocket A cutting tool having [a certain characteristic].

Images