cutting tools

Abstract

To provide a cutting tool having a long tool life.SOLUTION: A cutting tool includes a base material, and a film arranged on the base material, wherein the cutting tool includes a rake face, a flank face continuing to the rake face, and a cutting edge composed of a boundary part between the rake face and the flank face, the film includes a TiAlCeN layer, the TiAlCeN layer has a first TiAlCeN layer positioned on the flank face, a second TiAlCeN layer positioned on the rake face, and a third TiAlCeN layer positioned on the cutting edge.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to cutting tools. [Background technology]

[0002] Conventionally, in order to improve the performance of cutting tools, development of coatings that coat the surface of a substrate made of cemented carbide, cubic boron nitride sintered body, etc. has been underway. For example, Patent Document 1 discloses a coating film that coats the surface of a tool substrate with the composition formula: (Ti 1-x-y Al x M y )N z A cutting tool is disclosed that includes a composite nitride coating represented by the composition formula (wherein M is at least one of the group 6 elements of the periodic table, Y, Si, La, and Ce). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 166466 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, for example, a TiAlCeN film using cerium (Ce) as M has high hardness and excellent wear resistance of the cutting edge. However, when the TiAlCeN film is used for high-efficiency machining of high-hardness materials, the coating tends to be damaged on the flank and rake faces, resulting in a shortened tool life.

[0005] Therefore, an object of the present disclosure is to provide a cutting tool having a long tool life. [Means for solving the problem]

[0006] 1. A cutting tool comprising a substrate and a coating disposed on the substrate, The cutting tool comprises: Rake face, a flank surface connected to the rake surface; and a cutting edge formed by a boundary portion between the rake face and the flank face, the coating includes a TiAlCeN layer; The TiAlCeN layer is a first TiAlCeN layer located on the flank surface; a second TiAlCeN layer located on the rake face; a third TiAlCeN layer located on the cutting edge; The composition of the first TiAlCeN layer is Ti x1 Al y1 Ce z1 N, The composition of the second TiAlCeN layer is Ti x2 Al y2 Ce z2 N, The composition of the third TiAlCeN layer is Ti x3 Al y3 Ce z3 N, where: x1+y1+z1=1, x2+y2+z2=1, x3+y3+z3=1, 0.300 <y1≦0.700、 0.300 <y2≦0.700、 0.300 <y3≦0.700、 0 <z1≦0.090、 0 <z2≦0.090、 0.010 <z3≦0.100、 z3-z1≧0.010, and A cutting tool, wherein z3-z2≧0.010. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a cutting tool having a long tool life. [Brief explanation of the drawings]

[0008] [Figure 1]FIG. 1 is a perspective view illustrating an example of a cutting tool according to an embodiment of the present disclosure. [Figure 2] 2 is a cross-sectional view of the cutting tool of FIG. 1, taken along the line II-II in FIG. [Figure 3] FIG. 3 is a cross-sectional perspective view showing the shaded portion of FIG. 1, and shows the area III. [Figure 4] FIG. 4 is a partial view of the cross section shown in FIG. 2 in which the cutting edge has been honed. [Figure 5] FIG. 5 is a cross-sectional perspective view showing the cutting edge of the cutting tool shown in FIG. 3 after honing. [Figure 6] FIG. 6 is a partial view of the cross-sectional view shown in FIG. 2 in which a negative land is machined on the cutting edge. [Figure 7] FIG. 7 is a cross-sectional perspective view of the cutting edge shown in FIG. 3, in which a negative land is formed on the cutting edge. [Figure 8] FIG. 8 is a partial view of the cross section shown in FIG. 2 in which the cutting edge has been subjected to honing and negative land machining. [Figure 9] FIG. 9 is a cross-sectional perspective view of the cutting edge shown in FIG. 3, in which honing and negative land processing are performed on the cutting edge. [Figure 10] FIG. 10 is a schematic cross-sectional view illustrating an example of a coating of a cutting tool according to an embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram for explaining the cutting position of the cutting tool. [Figure 12] FIG. 12 is a diagram for explaining the cutting position of the cutting tool. [Figure 13] FIG. 13 is a diagram for explaining a method for setting the measurement field of view in measuring the composition of a TiAlCeN layer. [Figure 14] FIG. 14 is a schematic cross-sectional view illustrating an example of a coating of a cutting tool according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described. (1) The cutting tool of the present disclosure is 1. A cutting tool comprising a substrate and a coating disposed on the substrate, The cutting tool comprises: Rake face, a flank surface connected to the rake surface; and a cutting edge formed by a boundary portion between the rake face and the flank face, the coating includes a TiAlCeN layer; The TiAlCeN layer is a first TiAlCeN layer located on the flank surface; a second TiAlCeN layer located on the rake face; a third TiAlCeN layer located on the cutting edge; The composition of the first TiAlCeN layer is Ti x1 Al y1 Ce z1 N, The composition of the second TiAlCeN layer is Ti x2 Al y2 Ce z2 N, The composition of the third TiAlCeN layer is Ti x3 Al y3 Ce z3 N, where: x1+y1+z1=1, x2+y2+z2=1, x3+y3+z3=1, 0.300 <y1≦0.700、 0.300 <y2≦0.700、 0.300 <y3≦0.700、 0 <z1≦0.090、 0 <z2≦0.090、 0.010 <z3≦0.100、 z3-z1≧0.010, and A cutting tool, wherein z3-z2≧0.010.

[0010] According to the present disclosure, it is possible to provide a cutting tool having a long tool life.

[0011] (2) In the above (1), the thickness of the TiAlCeN layer is preferably 0.5 μm or more and 15 μm or less, which further improves the tool life.

[0012] (3) In the above (1) or (2), the coating further includes a first layer, The first layer is at least one element selected from the first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum, and silicon of the periodic table; or It is preferable that the first compound comprises at least one element selected from the first group and at least one element selected from the second group consisting of carbon, nitrogen, oxygen, and boron.

[0013] This further improves the tool life.

[0014] (4) In the above (3), the first group preferably consists of titanium, chromium, aluminum, and silicon, which further improves the tool life.

[0015] (5) In any of the above (1) to (4), the thickness of the coating is preferably 0.5 μm or more and 15 μm or less, which further improves the tool life.

[0016] (6) In the above (3) or (4), the coating preferably has a multilayer structure in which the TiAlCeN layers and the first layers are alternately stacked, thereby further improving tool life.

[0017] [Details of the embodiments of the present disclosure] Specific examples of cutting tools according to the present disclosure will be described below with reference to the drawings. In the drawings, the same reference numerals represent the same or corresponding parts. Furthermore, dimensional relationships such as length, width, thickness, and depth have been appropriately changed for clarity and simplification of the drawings, and do not necessarily represent actual dimensional relationships.

[0018] In this specification, the expression "A to B" means the upper and lower limits of a range (i.e., A or more and B or less), and when no unit is specified for A and a unit is specified only for B, the unit of A and the unit of B are the same.

[0019] In this specification, when a compound is expressed by a chemical formula, unless the atomic ratio is particularly limited, it is understood to include any conventionally known atomic ratio and is not necessarily limited to only the stoichiometric range. For example, when "TiCN" is written, the ratio of the numbers of atoms constituting TiCN includes any conventionally known atomic ratio.

[0020] In the present disclosure, when one or more numerical values ​​are listed as the lower limit and the upper limit of a numerical range, a combination of any one numerical value listed as the lower limit and any one numerical value listed as the upper limit is also disclosed. For example, when a1 or more, b1 or more, and c1 or more are listed as the lower limit and a2 or less, b2 or less, and c2 or less are listed as the upper limit, a1 or more and a2 or less, a1 or more and b2 or less, a1 or more and c2 or less, b1 or more and a2 or less, b1 or more and b2 or less, b1 or more and c2 or less, c1 or more and a2 or less, c1 or more and b2 or less, and c1 or more and c2 or less are also disclosed.

[0021] First, the inventors investigated the damage patterns of conventional tools during high-efficiency machining of hard materials in order to develop cutting tools with long tool life. Under these machining conditions, the cutting edge is prone to wear. On the flank face, a phenomenon known as notch wear, in which cracks easily develop at the contact boundary with the workpiece, deteriorates the surface roughness of the workpiece. On the rake face, the abrasive impact of the chips causes microchipping of the coating, easily spreading damage to the substrate.

[0022] From the above investigations, it is inferred that for a cutting tool to have a long tool life, it is important to have excellent wear resistance on the cutting edge and excellent fracture resistance on the flank and rake faces. However, because wear resistance and fracture resistance are contradictory properties, it has been difficult to improve fracture resistance and wear resistance in the same coating.

[0023] As a result of extensive research, the inventors have obtained a cutting tool that has a long tool life even under machining conditions that place a heavy load on the cutting edge by changing the composition of the coating on the cutting edge and the rake face or flank, thereby improving the fracture resistance of the cutting edge and the wear resistance of the rake face or flank in a well-balanced manner. One embodiment of the present invention (hereinafter also referred to as "this embodiment") will be described below, but the present embodiment is not limited thereto.

[0024] [Embodiment 1: Cutting tool (1)] A cutting tool according to an embodiment of the present disclosure comprises: 1. A cutting tool comprising a substrate and a coating disposed on the substrate, The cutting tool comprises: Rake face, a flank surface connected to the rake surface; and a cutting edge formed by a boundary portion between the rake face and the flank face, the coating includes a TiAlCeN layer; The TiAlCeN layer is a first TiAlCeN layer located on the flank surface; a second TiAlCeN layer located on the rake face; a third TiAlCeN layer located on the cutting edge; The composition of the first TiAlCeN layer is Ti x1 Al y1 Ce z1 N, The composition of the second TiAlCeN layer is Ti x2 Al y2 Ce z2 N, The composition of the third TiAlCeN layer is Ti x3 Al y3 Ce z3 N, where here x1 + y1 + z1 = 1, [[ID=,12]]x2 + y2 + z2 = 1, x3 + y3 + z3 = 1, 0.300 < y1 ≤ 0.700, 0.300 < y2 ≤ 0.700, 0.300 < y3 ≤ 0.700, 0 < z1 ≤ 0.090, 0 < z2 ≤ 0.090, 0.010 < z3 ≤ 0.100, z3 - z1 ≥ 0.010, and z3 - z2 ≥ 0.010, which is a cutting tool.<,

[0025] The cutting tool of the present disclosure can have a long tool life even in the high-efficiency machining of high-hardness materials. The reasons are presumed to be as follows (i) to (iii).

[0026] (i) In the cutting tool of the present embodiment, the composition of the third TiAlCeN layer located at the cutting edge is Ti x3 Al y3 Ce z3 N, where x3 + y3 + z3 = 1, 0.300 < y3 ≤ 0.700, and 0.010 < z3 ≤ 0.100. That is, the third TiAlCeN layer contains more than 30 atomic% and at most 70 atomic% of Al with respect to the total number of atoms of titanium (Ti), aluminum (Al), and cerium (Ce), and contains more than ,1.0 atomic% and at most 10.0 atomic% of Ce. Thereby, the third TiAlCeN layer can have excellent wear resistance, and wear of the cutting edge is suppressed.

[0027] (ii) In the cutting tool of this embodiment, the percentage of the number of Ce atoms relative to the total number of Ti, Al, and Ce atoms in the first TiAlCeN layer and the second TiAlCeN layer is 1% or more lower than that in the third TiAlCeN layer. Therefore, the first TiAlCeN layer and the second TiAlCeN layer have higher toughness than the third TiAlCeN layer. Therefore, the first TiAlCeN layer can suppress crack propagation on the flank face. Furthermore, the second TiAlCeN layer can suppress microchipping on the rake face.

[0028] (iii) As described above, the cutting tool of the present embodiment has a well-balanced improvement in the wear resistance of the cutting edge and the fracture resistance of the rake face and flank face, and therefore the cutting tool of the present disclosure can have a long tool life even in high-efficiency machining of high-hardness materials.

[0029] <Cutting tool structure> 1, the cutting tool 1 of this embodiment has a surface including an upper surface, a lower surface, and four side surfaces, and has an overall rectangular prism shape that is slightly thin in the vertical direction. Furthermore, the cutting tool 1 has a through-hole that penetrates the upper and lower surfaces, and at the boundaries between the four side surfaces of the cutting tool 1, adjacent side surfaces are connected by arc surfaces.

[0030] In the cutting tool 1 of this embodiment, the upper and lower surfaces form the rake face 11, and the four side surfaces (and the arc surfaces connecting these) form the flank 12. The boundary portion between the rake face 11 and the flank 12 functions as a cutting edge 13. In other words, the surfaces of the cutting tool 1 of this embodiment (the upper and lower surfaces, the four side surfaces, the arc surfaces connecting these side surfaces, and the inner peripheral surface of the through hole) include the rake face 11, the flank 12 connected to the rake face, and the cutting edge 13 consisting of the boundary portion between the rake face 11 and the flank 12.

[0031] The boundary portion between the rake face 11 and the flank 12, i.e., the cutting edge 13, means "the combined portion of the ridge line E that forms the boundary between the rake face 11 and the flank 12 and the portions of the rake face 11 and the flank 12 that are near the ridge line E." The "portions of the rake face 11 and the flank 12 that are near the ridge line E" are determined by the shape of the cutting edge 13 of the cutting tool 1. Below, we will explain the cases where the cutting tool 1 is a tool with a sharp edge shape, a tool with a honed shape that has been honed, and a tool with a negative land shape that has been negative land.

[0032] 2 and 3 show a cutting tool 1 with a sharp edge shape. In such a cutting tool 1 with a sharp edge shape, "portions of the rake face 11 and flank face 12 that are near the ridge line E" are defined as the region where the distance (linear distance) D from the ridge line E is 50 μm or less (the region indicated by dotted hatching in FIG. 3). Therefore, the cutting edge 13 of the cutting tool 1 with a sharp edge shape is the portion that corresponds to the region indicated by dotted hatching in FIG. 3.

[0033] 4 and 5 show a honed-shaped cutting tool 1 that has been honed. In addition to each part of the cutting tool 1, Figures 4 and 5 also show an imaginary plane R including the rake face 11, an imaginary plane F including the flank face 12, an imaginary ridge line EE formed by the intersection of the imaginary planes R and F, an imaginary boundary line ER that marks the boundary between the rake face 11 and the imaginary plane R, and an imaginary boundary line EF that marks the boundary between the flank face 12 and the imaginary plane F. Note that with respect to the honed-shaped cutting tool 1, the above-mentioned "ridge line E" should be read as "imaginary ridge line EE."

[0034] In such a honed cutting tool 1, "the portion of the rake face 11 and flank 12 near the imaginary ridge line EE" is defined as the region between the imaginary boundary lines ER and EF (the region indicated by dotted hatching in FIG. 5). Therefore, the cutting edge 13 in the honed cutting tool 1 is the portion corresponding to the region indicated by dotted hatching in FIG. 5.

[0035] 6 and 7 show a cutting tool 1 having a negative land shape that has been subjected to negative land machining. In addition to each part of the cutting tool 1, Figures 6 and 7 also show an imaginary plane R including the rake face 11, an imaginary plane F including the flank face 12, an imaginary ridge line EE formed by the intersection of the imaginary planes R and F, an imaginary boundary line ER that defines the boundary between the rake face 11 and the imaginary plane R, and an imaginary boundary line EF that defines the boundary between the flank face 12 and the imaginary plane F. It should be noted that, in the case of the cutting tool 1 having a negative land shape, the above-mentioned "ridge line E" is also referred to as "imaginary ridge line EE."

[0036] In such a cutting tool 1 having a negative land shape, "the portion of the rake face 11 and the flank face 12 near the imaginary ridge line EE" is defined as the region between the imaginary boundary lines ER and EF (the region indicated by dotted hatching in FIG. 7). Therefore, the cutting edge 13 in the cutting tool 1 having a negative land shape is the portion corresponding to the region indicated by dotted hatching in FIG. 7.

[0037] 8 and 9 show a cutting tool 1 having a shape that has been machined by combining honing and a negative land. In addition to each part of the cutting tool 1, FIGS. 8 and 9 also show an imaginary plane R including the rake face 11, an imaginary plane F including the flank face 12, an imaginary ridge line EE formed by the intersection of the imaginary planes R and F, an imaginary boundary line ER defining the boundary between the rake face 11 and the imaginary plane R, and an imaginary boundary line EF defining the boundary between the flank face 12 and the imaginary plane F. Note that, even in the case of a cutting tool 1 having a negative land shape, the above-mentioned "ridge line E" is replaced with "imaginary ridge line EE." Note that the imaginary plane R is the plane of the rake face 11 that includes the plane closest to the cutting edge 13.

[0038] In the cutting tool 1 having such a shape, "the portion of the rake face 11 and the flank face 12 near the imaginary ridge line EE" is defined as the region between the imaginary boundary line ER and the imaginary boundary line EF (the region indicated by dotted hatching in Fig. 8). Therefore, the cutting edge 13 of the cutting tool 1 corresponds to the region indicated by dotted hatching in Fig. 8.

[0039] FIG. 1 shows a cutting tool 1 as an indexable cutting tip for turning, but the cutting tool 1 is not limited to this and examples include drills, end mills, indexable cutting tips for drills, indexable cutting tips for end mills, indexable cutting tips for milling, metal saws, gear cutting tools, reamers, taps, etc.

[0040] Furthermore, when the cutting tool 1 is an indexable cutting tip or the like, the cutting tool 1 may have or may not have a chip breaker, and the cutting edge 13 may have any of the following shapes: a sharp edge (the ridge where the rake face and flank intersect) (see Figures 1 to 3), a honed edge (a sharp edge with a radius) (see Figures 4 and 5), a negative land (chamfered) (see Figures 6 and 7), or a combination of honing and negative land (see Figures 8 and 9).

[0041] As shown in Fig. 2, the cutting tool 1 includes a substrate 2 and a coating 3 disposed on the substrate 2. The coating 3 may be disposed on a portion of the surface of the substrate 2, or may be disposed on the entire surface. When the coating 3 is disposed on a portion of the surface of the substrate 2, the portion of the surface of the substrate 2 includes the entire area within a distance (straight-line distance) D of 200 µm from the ridge line E or the virtual ridge line EE. As long as the effects of the present disclosure are achieved, partial variations in the configuration of the coating 3 do not depart from the scope of this embodiment.

[0042] <Base material> As shown in FIGS. 2 and 3, the substrate 2 of this embodiment has a rake face 2a and a flank 2b. The boundary between the rake face 2a and the flank 2b forms the cutting edge 2c. The "boundary between the rake face 2a and the flank 2b" refers to the "combination of the ridgeline forming the boundary between the rake face 2a and the flank 2b and the portions of the rake face 2a and the flank 2b that are near the ridgeline," similar to the "boundary between the rake face 11 and the flank 12" described above. The "portion near the ridgeline of the rake face 2a and the flank 2b" is defined as described above depending on whether the shape of the cutting edge 13 of the cutting tool 1 is a sharp edge shape, a honed shape, or a negative land shape.

[0043] Any known substrate of this type can be used as the substrate 2. For example, cemented carbide (WC-based cemented carbide, cemented carbide containing WC and Co, cemented carbide containing Ti, Ta, Nb, or other carbonitrides), cermet (mainly composed of TiC, TiN, TiCN, or other materials), high-speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, or other materials), cubic boron nitride sintered body, or diamond sintered body are preferred. Among these various substrates, WC-based cemented carbide and cermet (particularly TiCN-based cermet) are particularly preferred. This is because these substrates have an excellent balance between hardness and strength, especially at high temperatures, and offer excellent properties as substrates for cutting tools.

[0044] <Coating> The coating 3 of the first embodiment has a TiAlCeN layer. The coating 3 of the present embodiment may or may not include other layers, so long as it has a TiAlCeN layer. Examples of other layers include a first layer. As shown in FIG. 10 , the first layer 31 can be provided between the substrate 2 and the TiAlCeN layer 30. In this case, the first layer 31 corresponds to the underlayer 32. The first layer 31 can be provided on the outermost surface of the coating 3. In this case, the first layer 31 corresponds to the surface layer 33. The coating can include one or both of the underlayer 32 and the surface layer 33. Details of the first layer will be described later.

[0045] The laminated structure of the coating 3 does not have to be uniform throughout the entire coating 20, and the laminated structure may be partially different.

[0046] The thickness of the coating 3 is preferably 0.5 μm or more and 15 μm or less. If the thickness of the coating is less than 0.5 μm, the tool life tends to be insufficient. If the thickness of the coating exceeds 15 μm, stress is generated in the coating during processing, and peeling or breakage is likely to occur. The thickness of the coating is more preferably 1.0 μm or more and 12.0 μm or less, and still more preferably 3.0 μm or more and 7.0 μm or less. The method for measuring the thickness of the coating will be described later.

[0047] <TiAlCeN layer> The TiAlCeN layer of the present embodiment has a first TiAlCeN layer located on the flank 12, a second TiAlCeN layer located on the rake face 11, and a third TiAlCeN layer located on the cutting edge 13. That is, in one TiAlCeN layer, there are regions composed of the first TiAlCeN layer, regions composed of the second TiAlCeN layer, and regions composed of the third TiAlCeN layer.

[0048] ≪Composition≫ The composition of the first TiAlCeN layer is Ti x1 Al y1 Ce z1 N, the composition of the second TiAlCeN layer is Ti x2 Al y2 Ce z2 N, and the composition of the third TiAlCeN layer is Ti x3 Al y3 Ce z3 N. Here, x1, y1, z1, x2, y2, z2, x3, y3, and z3 satisfy the following (1) to (11). (1) x1 + y1 + z1 = 1, (2) x2 + y2 + z2 = 1, (3) x3 + y3 + z3 = 1, (4) 0.300 < y1 ≤ 0.700, (5) 0.300 < y2 ≤ 0.700, (6)0.300 <y3≦0.700、 (7)0 <z1≦0.090、 (8)0 <z2≦0.090、 (9)0.010 <z3≦0.100、 (10)z3-z1≧0.010, (11)z3-z2≧0.010

[0049] From the viewpoint of improving the heat resistance of the first TiAlCeN layer, the lower limit of y1 is more than 0.300, preferably 0.310 or more, preferably 0.320 or more, preferably 0.330 or more, preferably 0.350 or more, and more preferably 0.400 or more. From the viewpoint of improving the hardness of the first TiAlCeN layer, the upper limit of y1 is 0.700 or less, preferably 0.650 or less, and more preferably 0.600 or less. y1 is more than 0.300 and 0.700 or less, preferably 0.350 or more and 0.650 or less, and more preferably 0.450 or more and 0.600 or less.

[0050] From the viewpoint of improving the wear resistance of the first TiAlCeN layer, the lower limit of z1 is greater than 0 and is preferably greater than or equal to 0.001, more preferably greater than or equal to 0.005, and more preferably greater than or equal to 0.010. From the viewpoint of improving the fracture resistance of the first TiAlCeN layer, the upper limit of z1 is 0.090 or less, preferably 0.065 or less, preferably 0.060 or less, preferably 0.040 or less, and more preferably 0.020 or less. z1 is greater than 0 and 0.090 or less, preferably 0.005 or more and 0.040 or less, and more preferably 0.010 or more and 0.020 or less.

[0051] From the viewpoint of improving the heat resistance of the second TiAlCeN layer, the lower limit of y2 is more than 0.300, preferably 0.310 or more, preferably 0.320 or more, preferably 0.330 or more, preferably 0.350 or more, and more preferably 0.400 or more. From the viewpoint of improving the film hardness of the second TiAlCeN layer, the upper limit of y2 is 0.700 or less, preferably 0.650 or less, and more preferably 0.600 or less. The above y2 is more than 0.300 but not more than 0.700, preferably 0.350 or more but not more than 0.650, and more preferably 0.400 or more but not more than 0.600.

[0052] From the viewpoint of improving the wear resistance of the second TiAlCeN layer, the lower limit of z2 is more than 0 and is preferably 0.001 or more, preferably 0.005 or more, and more preferably 0.010 or more. From the viewpoint of improving the chipping resistance of the second TiAlCeN layer, the upper limit of z2 is 0.090 or less, preferably 0.064 or less, preferably 0.060 or less, preferably 0.040 or less, and more preferably 0.020 or less. The z2 is more than 0 and 0.090 or less, preferably 0.005 or more and 0.040 or less, and more preferably 0.010 or more and 0.020 or less.

[0053] From the viewpoint of improving the heat resistance of the third TiAlCeN layer, the lower limit of y3 is more than 0.300, preferably 0.310 or more, preferably 0.320 or more, preferably 0.330 or more, preferably 0.350 or more, and more preferably 0.400 or more. From the viewpoint of improving the hardness of the third TiAlCeN layer, the upper limit of y3 is 0.700 or less, preferably 0.650 or less, and more preferably 0.600 or less. The above y3 is more than 0.300 and 0.700 or less, preferably 0.350 or more and 0.650 or less, and more preferably 0.400 or more and 0.600 or less.

[0054] From the viewpoint of improving the wear resistance of the third TiAlCeN layer, the lower limit of z3 is more than 0.010, preferably 0.011 or more, preferably 0.015 or more, more preferably 0.020 or more, and even more preferably 0.022 or more. From the viewpoint of improving the fracture resistance of the third TiAlCeN layer, the upper limit of z3 is 0.100 or less, preferably 0.095 or less, preferably 0.080 or less, preferably 0.065 or less, preferably 0.060 or less, preferably 0.050 or less, and more preferably 0.030 or less. The z3 is more than 0.010 but not more than 0.100, preferably 0.015 or more and 0.050 or less, and even more preferably 0.020 or more and 0.030 or less.

[0055] The lower limit of z3-z1 is 0.010 or more, preferably 0.013 or more, and more preferably 0.015 or more, from the viewpoint of improving the wear resistance and chipping resistance of the TiAlCeN layer in a well-balanced manner. The upper limit of z3-z1 is preferably 0.099 or less, preferably 0.090 or less, more preferably 0.050 or less, more preferably 0.035 or less, and even more preferably 0.030 or less, from the viewpoint of improving the peeling resistance of the TiAlCeN layer. z3-z1 is preferably 0.010 or more and 0.090 or less, more preferably 0.013 or more and 0.050 or less, and even more preferably 0.015 or more and 0.030 or less.

[0056] The lower limit of z3-z2 is 0.010 or more, preferably 0.013 or more, and more preferably 0.015 or more, from the viewpoint of improving the wear resistance and chipping resistance of the TiAlCeN layer in a well-balanced manner. The upper limit of z3-z2 is preferably 0.099 or less, preferably 0.090 or less, more preferably 0.050 or less, more preferably 0.035 or less, and even more preferably 0.030 or less, from the viewpoint of improving the peeling resistance of the TiAlCeN layer. z3-z2 is preferably 0.010 or more and 0.090 or less, more preferably 0.013 or more and 0.050 or less, and even more preferably 0.015 or more and 0.030 or less.

[0057] The above x1 can be calculated by x1=1-y1-z1. The above x2 can be calculated by x2=1-y2-z2. The above x3 can be calculated by x3=1-y3-z3.

[0058] The above x1, y1, z1, x2, y2, z2, x3, y3, and z3 can be determined by measuring the composition of each region (flank face region, rake face region, and cutting edge region) of the TiAlCeN layer using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer (SEM-EDS). A specific measurement method will be described below.

[0059] (A1) A measurement sample is obtained by cutting the cutting tool 1 so as to expose a cross section along the thickness direction of the coating 3. The cutting position is determined as follows, taking into account the actual usage conditions of the cutting tool.

[0060] 11 and 12 are diagrams illustrating the cutting position of the cutting tool. When the cutting tool 1 is used to cut a workpiece with the cutting edge 13 of a corner portion (a portion with an apex angle that forms an arc), the cutting is performed so that a cross section that includes a line L1 that bisects the corner portion and that runs along the thickness direction of the coating 3 is exposed, as shown in FIG. 11. On the other hand, when the cutting tool 1 is used to cut a workpiece with the cutting edge 13 of a straight portion (a portion that forms a straight line), the cutting is performed so that a cross section that includes a line L2 that is perpendicular to the cutting edge of the straight portion and that runs along the thickness direction of the coating 3 is exposed, as shown in FIG. 12. If necessary, the exposed cut surface is polished to make it smooth.

[0061] (B1) The above cut surface is observed at 5000x magnification using SEM-EDS, and three rectangular measurement fields of view, each measuring 15 μm or more in the thickness direction of the coating and 15 μm or more in the direction perpendicular to the thickness direction, are set so as to include the first TiAlCeN layer located on the flank face. The measurement fields are set so as to include the entire first TiAlCeN layer in the thickness direction. The measurement fields are set so that the first TiAlCeN layer is the first TiAlCeN layer located on the flank face at a distance of 100 μm to 200 μm from the ridge line E or the virtual ridge line EE.

[0062] As shown in Fig. 13, the three measurement fields are set so that the sides of each measurement field are in contact with each other in the thickness direction (the direction indicated by arrow T in Fig. 13) and so that the measurement fields are continuous. The measurement fields may partially overlap (the overlapping parts are indicated by diagonal lines in Fig. 13). In this case, the measurement fields are set so that the length of the overlapping parts of the sides in the direction perpendicular to the thickness direction (the direction indicated by arrow H in Fig. 13) is 2 µm or less.

[0063] (C1) In each of the three measurement fields, the region of the first TiAlCeN layer is identified. Specifically, element mapping is performed by SEM-EDS for each measurement field to identify the layer containing Ti, Al, and Ce. The identified layer corresponds to the first TiAlCeN layer.

[0064] (D1) For each of the three measurement fields, the composition ratios of Al, Ti, and Ce in the first TiAlCeN layer are analyzed, and the ratio x1 of Ti, the ratio y1 of Al, and the ratio z1 of Ce relative to the total number of Al, Ti, and Ce atoms are calculated. The average value of x1 for the three measurement fields is determined as the composition Ti of the first TiAlCeN layer of this embodiment. x1 Al y1 Ce z1 The average value of y1 in the three measurement fields corresponds to the composition TiAlCeN of the first TiAlCeN layer of this embodiment. x1 Al y1 Ce z1The average value of z1 in the three measurement fields corresponds to the composition TiAlCeN of the first TiAlCeN layer of this embodiment. x1 Al y1 Ce z1 This corresponds to z1 in N.

[0065] The composition of the second TiAlCeN layer located on the rake face is Ti x2 Al y2 Ce z2 x2, y2, and z2 in N are also measured in the same manner as x1, y1, and z1 above, except that the position of the measurement field is set to include the second TiAlCeN layer. The measurement field is set so that the second TiAlCeN layer included in the measurement field is the second TiAlCeN layer located on the rake face at a distance of 200 μm or less from the ridge line E or the virtual ridge line EE.

[0066] The composition of the third TiAlCeN layer located at the cutting edge is Ti x3 Al y3 Ce z3 For x3, y3, and z3 in N, they are measured in the same manner as for x1, y1, and z1 above, except that the position of the measurement field is set to include the third TiAlCeN layer. The measurement field is set so that the third TiAlCeN layer included in the measurement field is the third TiAlCeN layer located on the cutting edge at a distance of 50 μm or less from the ridge line E or the virtual ridge line EE.

[0067] The above-mentioned SEM-EDS analysis can be performed using, for example, a scanning electron microscope (S-3400N, manufactured by Hitachi High-Technologies Corporation) under the following conditions. Accelerating voltage: 15 kV Process time: 5 Spectral range: 0 to 20 keV Number of channels: 1K Number of frames: 150 X-ray take-off angle: 30°.

[0068] It has been confirmed that as long as measurements are made using the same cutting tool, there is no variation in the measurement results even if the measurement location is selected arbitrarily.

[0069] The composition of the first TiAlCeN layer in this embodiment is Ti x1 Al y1 Ce z1 In N, the total number of Ti, Al and Ce atoms, A M1 Atomic number of N N1 Ratio A N1 / A M1 The composition Ti of the second TiAlCeN layer of this embodiment is necessarily in the range of 0.8 to 1.2. x2 Al y2 Ce z2 In N, the total number of Ti, Al and Ce atoms, A M2 Atomic number of N N2 Ratio A N2 / A M2 The composition Ti of the third TiAlCeN layer of this embodiment is necessarily in the range of 0.8 to 1.2. x3 Al y3 Ce z3 In N, the total number of Ti, Al and Ce atoms, A M3 Atomic number of N N3 Ratio A N3 / A M3 is necessarily in the range of 0.8 to 1.2 in terms of manufacturing.

[0070] Above ratio A N1 / A M1 , ratio A N2 / A M2 and ratio A N3 / A M3 can be measured by the Rutherford backscattering (RBS) method. N1 / A M1 , ratio A N2 / A M2 and ratio A N3 / A M3 It has been confirmed that the effects of the present disclosure are not impaired if the value is within the above range.

[0071] <Thickness> In this embodiment, the thickness of the TiAlCeN layer is preferably 0.5 μm or more and 15 μm or less. If the thickness of the TiAlCeN layer is less than 0.5 μm, it is difficult to obtain the effect of improving the wear resistance and chipping resistance of the TiAlCeN layer, and the tool life tends to be insufficient. If the thickness of the TiAlCeN layer exceeds 15 μm, stress is generated in the TiAlCeN layer during machining, making it more likely to peel or break. The thickness of the TiAlCeN layer is more preferably 1 μm or more and 12 μm or less, and even more preferably 3 μm or more and 7 μm or less. The thickness of the TiAlCeN layer is measured as follows.

[0072] (A2) Using the same method as that described in (A1) of the method for measuring the composition of the first TiAlCeN layer, the cutting tool is cut so that a cross section along the thickness direction of the coating is exposed, to obtain a measurement sample.

[0073] (B2) The cross section is observed at 1500x magnification using a scanning electron microscope (S-3400N, manufactured by Hitachi High-Technologies Corporation), and the thickness of the TiAlCeN layer is measured at three arbitrary locations on each of the rake face and flank face along the normal direction of the substrate surface. The arithmetic mean of these measurements corresponds to the "TiAlCeN layer thickness." The SEM measurement conditions are the same as those described in (D1) of the first method for measuring the composition of the TiAlCeN layer.

[0074] It has been confirmed that as long as measurements are made using the same cutting tool, there is no variation in the measurement results even if the measurement location is selected arbitrarily.

[0075] In this embodiment, the thickness of the coating and the thickness of the first layer are also measured using the same procedure as above. It has been confirmed that, as long as the same cutting tool is used to measure these thicknesses, there is no variation in the measurement results even if the measurement location is arbitrarily selected.

[0076] <Crystal structure> In this embodiment, the TiAlCeN layer preferably has a cubic crystal structure. This allows the TiAlCeN layer to have high hardness and excellent wear resistance. Here, "the TiAlCeN layer has a cubic crystal structure" means that when the X-ray diffraction spectrum of the TiAlCeN layer is measured, peaks derived from the cubic crystal structure are observed, and peaks derived from crystal structures other than the cubic crystal structure (e.g., wurtzite crystal structure) are not observed (i.e., below the detection limit). Such an X-ray diffraction spectrum is measured as follows.

[0077] A flat portion of the tool flank is cut out and fixed to a holder to prepare a sample. The sample is then polished as necessary to smooth the surface to be measured. If any other layer is formed on the TiAlCeN layer, that layer is removed by polishing or other means, and the surface of the TiAlCeN layer is then smoothed. Next, an X-ray diffractometer (XRD) is used to perform X-ray diffraction on the TiAlCeN layer, and an X-ray diffraction spectrum is obtained.

[0078] The above-mentioned X-ray diffraction can be measured, for example, using an X-ray diffractometer (SmartLab (registered trademark), manufactured by Rigaku Corporation) under the following conditions. Diffraction method: θ-2θ method X-ray source: Cu-Kα ray (1.541862Å) Detector: D / Tex Ultra250 Tube voltage: 45kV Tube current: 200mA Scan speed: 20° / min Scan range: 15~85° Slit: 2.0mm.

[0079] ≪First layer≫ The coating 3 of this embodiment further includes a first layer, which preferably comprises at least one element selected from a first group consisting of Group 4, Group 5, and Group 6 elements, aluminum, and silicon, or a first compound comprising at least one element selected from Group 1 and at least one element selected from Group 2 consisting of carbon, nitrogen, oxygen, and boron. Elements in Group 4 of the periodic table include titanium (Ti), zirconium (Zr), and hafnium (Hf). Elements in Group 5 of the periodic table include vanadium (V), niobium (Nb), and tantalum (Ta). Elements in Group 6 of the periodic table include chromium (Cr), molybdenum (Mo), and tungsten (W).

[0080] The first group preferably consists of titanium, chromium, aluminum, and silicon. That is, the first layer preferably consists of a first compound consisting of at least one element selected from the group consisting of titanium, chromium, aluminum, and silicon, or at least one element selected from the group consisting of titanium, chromium, aluminum, and silicon and at least one element selected from the second group consisting of carbon, nitrogen, oxygen, and boron. This further improves tool life.

[0081] Examples of the first compound include TiAlN, TiAlSiCN, TiAlSiON, TiAlSiN, TiCrSiN, TiAlCrSiN, AlCrN, AlCrO, AlCrSiN, TiZrN, TiAlMoN, TiAlNbN, TiSiN, AlCrTaN, AlTiVN, TiB2, TiCrHfN, CrSiWN, TiAlCN, TiSiCN, AlZrON, AlCrCN, AlHfN, CrSiBON, CrAlBN, TiAlWN, AlCrMoCN, TiAlBN, TiAlCrSiBCNO, ZrN, ZrB2, ZrCN, CrSiBN, and AlCrBN.

[0082] The first layer can be provided between the substrate and the TiAlCeN layer. In this case, the first layer corresponds to an underlayer. The underlayer can improve adhesion between the substrate and the coating, and also improve the wear resistance of the coating. When the first layer is an underlayer, the first layer is preferably made of TiAlN, TiN, or AlCrN. In this case, the thickness of the first layer is preferably 0.2 μm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less.

[0083] The first layer can be formed on the outermost surface of the coating. In this case, the first layer corresponds to a surface layer. The surface layer can improve the thermal crack resistance and wear resistance of the coating. When the first layer is a surface layer, the first layer is preferably made of TiCN, TiAlBN, TiAlSiN, or TiN. In this case, the thickness of the first layer is preferably 0.2 μm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less.

[0084] [Embodiment 2: Cutting tool (2)] A cutting tool according to one embodiment of the present disclosure (hereinafter also referred to as "Embodiment 2") can have the same configuration as Embodiment 1, except that it includes a multilayer structure in which TiAlCeN layers and first layers are alternately stacked. Therefore, the multilayer structure will be described below.

[0085] ≪Multilayer structure≫ 14, the coating 3 of this embodiment preferably includes a multilayer structure in which TiAlCeN layers 30 and first layers 31 are alternately stacked. This makes it possible to suppress the propagation of cracks from the surface of the coating that occur near the interface between the TiAlCeN layer and the first layer during use of the cutting tool. This improves the tool life of the cutting tool.

[0086] The multilayer structure may include a first multilayer structure in which first TiAlCeN layers and the first layer are alternately stacked, a second multilayer structure in which second TiAlCeN layers and the first layer are alternately stacked, and a second multilayer structure in which third TiAlCeN layers and the first layer are alternately stacked. The first multilayer structure is located on the flank face, the second multilayer structure is located on the rake face, and the third multilayer structure is located on the cutting edge.

[0087] The number of stacked TiAlCeN layers and first layers is not particularly limited, as long as the multilayer structure includes at least one TiAlCeN layer and at least one first layer. The number of stacked layers refers to the total number of TiAlCeN layers and first layers included in the multilayer structure. The number of stacked layers is preferably 10 to 5,000, more preferably 200 to 5,000, more preferably 400 to 2,000, and even more preferably 500 to 1,000. In the multilayer structure, the layer closest to the substrate may be either the TiAlCeN layer or the first layer. In addition, in the multilayer structure, the layer farthest from the substrate may be either the TiAlCeN layer or the first layer. Here, the TiAlCeN layer refers to the first TiAlCeN layer, the second TiAlCeN layer, or the third TiAlCeN layer.

[0088] The thickness of the multilayer structure is preferably 0.5 μm or more and 15 μm or less, more preferably 1 μm or more and 12 μm or less. The thickness of the multilayer structure is measured by the method for measuring the thickness of a TiAlCeN layer described in embodiment 1, except that the multilayer structure is used as the measurement target.

[0089] It has been confirmed that as long as measurements are made using the same cutting tool, there is no variation in the measurement results even if the measurement location is selected arbitrarily.

[0090] In the above multilayer structure, the TiAlCeN layer and the first layer each preferably have a thickness of 2 nm to 50 nm. By alternately repeating such thin layers, crack propagation can be suppressed, and delamination can also be suppressed. If the thickness of each of the TiAlCeN layer and the first layer is less than 2 nm, the effect of suppressing crack propagation may be reduced. Furthermore, if the thickness of each of the TiAlCeN layer and the first layer is more than 50 nm, the effect of suppressing delamination may be reduced.

[0091] In the above multilayer structure, the thickness of each of the TiAlCeN layer and the first layer is preferably 2 nm or more and 50 nm or less, more preferably 4 nm or more and 40 nm or less, and even more preferably 5 nm or more and 30 nm or less.

[0092] The thickness of each of the TiAlCeN layer and the first layer in the above multilayer structure was measured as follows.

[0093] (A3) Using the same method as that described in (A1) of the method for measuring the composition of the first TiAlCeN layer, the cutting tool is cut so that a cross section along the thickness direction of the coating is exposed, to obtain a measurement sample.

[0094] (B3) The above cross section is observed at approximately 1,000,000 magnification using a scanning electron microscope (S-3400N, manufactured by Hitachi High-Technologies Corporation). The thickness of one TiAlCeN layer is measured at three locations. The arithmetic mean value of the thicknesses at the three locations is calculated, and this arithmetic mean value is defined as the thickness of the TiAlCeN layer. The thickness of one first layer is measured at three locations. The arithmetic mean value of the thicknesses at the three locations is calculated, and this arithmetic mean value is defined as the thickness of the first layer.

[0095] For each of the three different TiAlCeN layers, the thickness of the TiAlCeN layer is measured using the above procedure. The arithmetic mean value of the thicknesses of the three TiAlCeN layers is determined. This arithmetic mean value is used as the thickness of the TiAlCeN layer in the multilayer structure. For each of the three different first layers, the thickness of the first layer is measured using the above procedure. The arithmetic mean value of the thicknesses of the three first layers is determined. This arithmetic mean value is used as the thickness of the first layer in the multilayer structure.

[0096] It has been confirmed that as long as measurements are made using the same cutting tool, there is no variation in the measurement results even if the measurement location is selected arbitrarily.

[0097] The composition of the TiAlCeN layer in the multilayer structure is measured by the following procedure: Three measurement fields are set in the same manner as steps (A1) to (D1) of the method for measuring the composition (x1, y1, z1, x2, y2, z2, x3, y3, z3) of the TiAlCeN layer described in embodiment 1.

[0098] In each measurement field, five layers of each of the first TiAlCeN layer, the second TiAlCeN layer, and the third TiAlCeN layer are arbitrarily selected and measured, and the average composition of the five layers of each of the first TiAlCeN layer, the second TiAlCeN layer, and the third TiAlCeN layer is determined.

[0099] The average composition of the five first TiAlCeN layers is defined as the composition of the first TiAlCeN layer in the measurement field. The average composition of the first TiAlCeN layers in the three measurement fields is defined as the composition of the first TiAlCeN layer in the multilayer structure of this embodiment.

[0100] The average composition of the five second TiAlCeN layers is defined as the composition of the second TiAlCeN layer in the measurement field. The average composition of the second TiAlCeN layers in the three measurement fields is defined as the composition of the second TiAlCeN layer in the multilayer structure of this embodiment.

[0101] The average composition of the five third TiAlCeN layers is defined as the composition of the third TiAlCeN layer in the measurement field. The average composition of the third TiAlCeN layers in the three measurement fields is defined as the composition of the third TiAlCeN layer in the multilayer structure of this embodiment.

[0102] It has been confirmed that as long as measurements are made using the same cutting tool, there is no variation in the measurement results even if the measurement location is selected arbitrarily.

[0103] [Embodiment 3: Method for manufacturing a cutting tool] In embodiment 3, a method for manufacturing the cutting tool of embodiment 1 or embodiment 2 is described. The manufacturing method can include a step of preparing a substrate and a step of forming a coating on the substrate. Details of each step are described below.

[0104] <Process of preparing substrate> In the step of preparing a substrate, a substrate 2 is prepared. The substrate 2 may be the substrate described in embodiment 1.

[0105] For example, when a cemented carbide is used as the substrate, a commercially available substrate may be used, or it may be manufactured by a general powder metallurgy method. When manufactured by a general powder metallurgy method, for example, WC powder and Co powder are mixed using a ball mill or the like to obtain a mixed powder. The mixed powder is then dried and molded into a predetermined shape to obtain a green body. The green body is then sintered to obtain a WC-Co based cemented carbide (sintered body). The sintered body is then subjected to a predetermined cutting edge processing such as honing, thereby producing a substrate made of a WC-Co based cemented carbide. Any substrate other than those mentioned above can also be prepared as long as it is a conventionally known substrate of this type.

[0106] <<Coating Forming Process>> In the step of forming a coating, the coating 3 is formed on the substrate 2. In this embodiment, the coating 3 can be formed by a physical vapor deposition (PVD) method. Specific examples of the PVD method include an arc ion plating (AIP) method, a balanced magnetron sputtering (BMS) method, and an unbalanced magnetron sputtering (UBMS) method. In this embodiment, it is preferable to use arc ion plating.

[0107] In the AIP method, an arc discharge is generated using a target material as a cathode. This causes the target material to evaporate and ionize. The ions are then deposited on the surface of a substrate 2 to which a negative bias voltage is applied. The AIP method is excellent in terms of the ionization rate of the target material. The specific film formation method is as follows.

[0108] A target material and a substrate are placed in the chamber of the deposition system. The substrate is held in a rotatable substrate holder. Depending on the composition of the coating to be formed, alloy targets with varying particle sizes of Ti, Al, Ce, etc., or multiple targets with different compositions can be used. The composition of the coating can also be changed by adjusting the reaction gas pressure and / or the rotation speed of the substrate holder.

[0109] Subsequently, the surface of the substrate 2 is cleaned by ion bombardment treatment using Ar ions. The ion bombardment treatment can be carried out under conventionally known conditions.

[0110] When the coating includes a first layer as a base layer, the first layer is formed on the surface of the substrate 2. For example, a TiAlN layer, a TiN layer, or an AlCrN layer is formed on the surface of the substrate 2. The first layer can be formed by a conventionally known method.

[0111] Next, a TiAlCeN layer is formed on the substrate or the underlayer. The TiAlCeN layer can be formed under the conditions of either applying a pulsed arc to a cathode made of a target material (hereinafter also referred to as "Method A") or introducing a rare gas such as argon (Ar), krypton (Kr), or xenon (Xe) in addition to nitrogen gas during film formation (hereinafter also referred to as "Method B").

[0112] In Method A, nitrogen gas is introduced into the chamber, and while the substrate holder holding the substrate 2 is rotating, a pulsed arc is applied to a cathode made of a target material to generate an arc discharge, evaporating and ionizing the target material. A constant negative bias voltage is then applied to the substrate 2, and a TiAlCeN layer is formed on the substrate 2. The inventors have newly discovered that, using Method A, the Ce content (atomic %) of the third TiAlCeN layer formed on the cutting edge is greater than the Ce content (atomic %) of the first TiAlCeN layer formed on the flank face and the second TiAlCeN layer located on the rake face. The reason for this is presumed to be as follows.

[0113] When the arc is applied in pulses, high energy is imparted to the ions, increasing the number of ions flying toward the substrate 2. Ce, being a heavy element, has high energy, and when the Ce ions reach the substrate 2, they repel other elements (such as Al and Ti) present on the surface of the substrate 2. Generally, when a certain bias voltage is applied to the substrate, electrons concentrate on the cutting edge. Therefore, the Ce ions repel the Al and Ti already present on the cutting edge, making it easier for Ce to remain on the cutting edge, increasing the Ce content (atomic %) in the TiAlCeN layer on the cutting edge. Therefore, the Ce content (atomic %) of the third TiAlCeN layer formed on the cutting edge is higher than the Ce content (atomic %) in the first TiAlCeN layer formed on the flank face and the second TiAlCeN layer formed on the rake face.

[0114] The conditions for forming the TiAlCeN layer in Method A can be as follows. Base material temperature: 450~600℃ Bias voltage: -30 to -300V Arc current: 100~200A Pulse arc frequency: 0.2 to 1.0 kHz Reaction gas pressure: 3 to 6 Pa Nitrogen gas flow rate: 500 to 2000 sccm

[0115] In conventional TiAlCeN layer deposition, a constant arc is applied to a cathode made of a target material. Although Ce has a large energy, its weight results in a small amount reaching the substrate, resulting in a small effect of repelling Al and Ti. Therefore, the composition of the TiAlCeN layer is nearly identical on the flank, rake, and cutting edge, and the above relationships z3 - z1 ≥ 0.010 and z3 - z2 ≥ 0.010 cannot be satisfied. Conventionally, pulsed arc has been used as a method for improving droplets, and the use of pulsed arc to control the composition of a coating was a method that would not have occurred to those skilled in the art.

[0116] In Method B, nitrogen gas and a rare gas such as argon (Ar), krypton (Kr), or xenon (Xe) are introduced into a chamber. While rotating the substrate holder holding the substrate 2, a constant arc is applied to a cathode made of a target material, generating an arc discharge that evaporates and ionizes the target material. A constant negative bias voltage is then applied to the substrate 2, and a TiAlCeN layer is formed on the substrate 2. The inventors have newly discovered that, using Method B, the Ce content (atomic %) of the third TiAlCeN layer formed on the cutting edge is greater than the Ce content (atomic %) of the first TiAlCeN layer formed on the flank face and the second TiAlCeN layer located on the rake face. The reason for this is believed to be as follows.

[0117] When a rare gas is introduced into the chamber, sputtering occurs on the substrate simultaneously with film formation, sputtering the coating material. Generally, when a certain bias voltage is applied to the substrate, electrons concentrate on the cutting edge. The rare gas ions that cause sputtering concentrate on the electrons on the cutting edge, causing more sputtering on the cutting edge. The rate at which Ce is sputtered (sputtering rate) is lower than the rates at which Al and Ti are sputtered. Therefore, the Ce content (atomic %) in the third TiAlCeN layer on the cutting edge is greater than the Ce content (atomic %) in the first TiAlCeN layer on the flank face and the second TiAlCeN layer on the rake face.

[0118] The conditions for forming the TiAlCeN layer in Method B can be as follows. Base material temperature: 450~600℃ Bias voltage: -50 to -500V Arc current (constant): 80~220A Reaction gas pressure: 3 to 6 Pa Nitrogen gas flow rate: 500 to 2000 sccm Noble gas flow rate: 20~500sccm

[0119] In conventional TiAlCeN layer deposition, nitrogen gas was introduced, but no rare gas was introduced. This resulted in the absence of sputter ions and no sputtering, so the composition of the TiAlCeN layer was nearly identical on the flank face, rake face, and cutting edge, and the above relationships z3 - z1 ≥ 0.010 and z3 - z2 ≥ 0.010 could not be satisfied. Conventionally, the introduction of rare gases was thought to result in the disadvantage of a reduced deposition rate, and therefore the introduction of rare gases was not adopted by those skilled in the art.

[0120] A multilayer structure in which TiAlCeN layers and the first layer are alternately stacked can be formed by placing a target for depositing the TiAlCeN layer and a target for depositing the first layer in a chamber and setting the rotation frequency of the rotating holder to, for example, 2 to 5 rpm.

[0121] Next, if the coating includes a first layer as a surface layer, the first layer is formed on the surface of the TiAlCeN layer. For example, a TiCN layer, a TiAlBN layer, a TiAlSiN layer, or a TiN layer is formed on the surface of the TiAlCeN layer. The first layer can be formed by a conventionally known method.

[0122] As described above, the cutting tool 1 including the substrate 2 and the coating 3 provided on the substrate 2 can be manufactured.

[0123] [Appendix 1] 1. A cutting tool comprising a substrate and a coating disposed on the substrate, The cutting tool comprises: Rake face, a flank surface connected to the rake surface; and a cutting edge formed by a boundary portion between the rake face and the flank face, the coating includes a TiAlCeN layer; The TiAlCeN layer is a first TiAlCeN layer located on the flank surface; a second TiAlCeN layer located on the rake face; a third TiAlCeN layer located on the cutting edge; The composition of the first TiAlCeN layer is Ti x1 Al y1 Ce z1 N, The composition of the second TiAlCeN layer is Ti x2 Al y2 Ce z2 N, The composition of the third TiAlCeN layer is Ti x3 Al y3 Ce z3 N, where: x1+y1+z1=1, x2+y2+z2=1, x3+y3+z3=1, 0.300 <y1≦0.700、 0.300 <y2≦0.700、 0.300 <y3≦0.700、 0 <z1≦0.090、 0 <z2≦0.090、 0.010 <z3≦0.100、 z3-z1≧0.010, and A cutting tool, wherein z3-z2≧0.010.

[0124] [Appendix 2] 2. The cutting tool of claim 1, wherein the TiAlCeN layer has a thickness of 0.5 μm or more and 15 μm or less.

[0125] [Appendix 3] the coating further comprises a first layer; The first layer is at least one element selected from the first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum, and silicon of the periodic table; or 3. The cutting tool according to claim 1 or 2, comprising a first compound comprising at least one element selected from the first group and at least one element selected from a second group consisting of carbon, nitrogen, oxygen, and boron.

[0126] [Appendix 4] 4. The cutting tool of claim 3, wherein the first group consists of titanium, chromium, aluminum, and silicon.

[0127] [Appendix 5] 5. The cutting tool according to claim 1, wherein the coating has a thickness of 0.5 μm or more and 15 μm or less.

[0128] [Appendix 6] 5. The cutting tool of claim 3, wherein the coating includes a multilayer structure in which the TiAlCeN layers and the first layers are alternately stacked. [Example]

[0129] The present embodiment will be described in more detail with reference to examples, although the present embodiment is not limited to these examples.

[0130] [Example 1] <Cutting tool manufacturing> Cutting tools were produced and their tool lives were evaluated as follows. <Process of preparing substrate> A turning tip made of cubic boron nitride sintered body (model number: DNGA150408 (manufactured by Sumitomo Electric Hardmetal Corp.)) was prepared as a substrate. The substrate was placed on a substrate holder of an arc ion plating device.

[0131] <<Coating Forming Process>> As target materials, sintered alloys were prepared having the compositions shown in the "TiAlCeN layer" and "first layer" columns of "target material composition" in Table 1. For example, for Sample 11, a sintered alloy with an atomic ratio of "Ti:Al:Ce=0.55:0.35:0.10" was prepared as the target material for forming the TiAlCeN layer (hereinafter also referred to as the "TiAlCeN layer target"), and a sintered alloy with an atomic ratio of "Ti:Al:B=0.50:0.45:0.05" was prepared as the target material for forming the first layer (hereinafter also referred to as the "first layer target").

[0132] The target material was placed in the arc evaporation source of an arc ion plating device. When two types of target materials were used, they were placed in different arc evaporation sources. Next, the chamber of the device was evacuated to a vacuum of 0.5 Pa or less, and the substrate temperature was heated to 450°C. Ar gas was then introduced into the chamber to create an Ar atmosphere of 2.5 Pa. In this state, a bias voltage of -800 V was applied to the substrate, and ion bombardment treatment with Ar gas was performed to clean the surface of the substrate.

[0133] (Samples 1 to 6, Sample 14, Sample 15, Sample 17, Sample 18, Sample 20, Sample 22, Sample 23, Sample 1-2, Sample 1-6, Sample 1-7) Nitrogen gas was introduced into the chamber to create a reaction atmosphere of 3.5 Pa. While the substrate holder holding the substrate 2 was rotating, a pulsed arc was applied to the cathode, consisting of the target material, to generate an arc discharge, evaporating and ionizing the target material. A TiAlCeN layer was then formed on the substrate 2, to which a constant negative bias voltage was applied, to obtain a cutting tool. The bias voltage, arc current, and pulse arc frequency during film formation were as shown in Table 1 under "TiAlCeN Layer Formation Conditions." For example, for Sample 1, the bias voltage was -30 V, the arc current was 130 A, and the pulse arc frequency was 0.5 kHz. The substrate temperature during film formation was 500°C, and the nitrogen gas flow rate was 900 sccm.

[0134] (Samples 7 to 9, 16, and 21) Nitrogen gas and the type of rare gas listed under "Method B" in Table 1 under "TiAlCeN Layer Formation Conditions" were introduced into the chamber. While rotating the substrate holder holding the substrate 2, a constant arc was applied to the cathode consisting of the target material, causing an arc discharge that evaporated and ionized the target material. A constant negative bias voltage was then applied to the substrate 2, forming a TiAlCeN layer on the substrate, resulting in a cutting tool. The chamber pressure (reactant gas pressure) during film formation was 4 Pa. The substrate temperature during film formation was 550°C, the nitrogen gas flow rate was 1000 sccm, and the bias voltage, arc current, and rare gas flow rate during film formation were as listed under "TiAlCeN Layer Formation Conditions" in Table 1.

[0135] (Sample 10) Nitrogen gas and the type of rare gas listed under "Method B" in Table 1 under "TiAlCeN Layer Formation Conditions" were introduced into the chamber, and while the substrate holder holding the substrate 2 was rotating, a constant arc was applied to the cathode consisting of the target material, causing an arc discharge that evaporated and ionized the target material. A TiAlCeN layer was then formed on the substrate 2 to which a constant negative bias voltage was applied. The pressure inside the chamber (reactant gas pressure) during film formation was 3 Pa. The substrate temperature during film formation was 450°C, the nitrogen gas flow rate was 600 sccm, and the bias voltage, arc current, and rare gas flow rate during film formation were as listed under Table 1 under "TiAlCeN Layer Formation Conditions."

[0136] Next, using the target for the first layer, nitrogen gas and methane gas were introduced from the gas inlet, and while rotating the substrate holder, the first layer (TiCN layer) was formed as a surface layer on the TiAlCeN layer, thereby obtaining a cutting tool.

[0137] (Sample 11, Samples 1-5) Nitrogen gas and the type of rare gas listed under "Method B" in Table 1 under "TiAlCeN Layer Formation Conditions" were introduced into the chamber. While rotating the substrate holder holding the substrate 2, a constant arc was applied to the cathode consisting of the target material, generating an arc discharge that evaporated and ionized the target material. A TiAlCeN layer was then formed on the substrate 2 to which a constant negative bias voltage was applied. The flow rate of the rare gas during film formation was as listed under "TiAlCeN Layer Formation Conditions" in Table 1. The chamber pressure (reactant gas pressure) during film formation was 3.5 Pa. The substrate temperature during film formation was 600°C, the nitrogen gas flow rate was 800 sccm, and the bias voltage, arc current, and rare gas flow rate were as listed under "TiAlCeN Layer Formation Conditions" in Table 1.

[0138] Next, using the target for the first layer, nitrogen gas was introduced from the gas inlet, and the substrate holder was rotated to form the first layer (TiAlBN layer) as a surface layer on the TiAlCeN layer, thereby obtaining a cutting tool.

[0139] (Sample 13) The targets for the TiAlCeN layer and the AlCrN layer were positioned adjacent to each other in the chamber. Nitrogen gas was introduced into the chamber to create a reaction atmosphere of 3.5 Pa. While the substrate holder was rotating at 5 rpm, a pulsed arc was applied to the cathode made of the target material, generating an arc discharge that evaporated and ionized the target material. A constant negative bias voltage was applied to the substrate 2, and alternating TiAlCeN and AlCrN layers were then formed on the substrate, forming a multilayer coating and producing a cutting tool. The bias voltage, arc current, and pulsed arc frequency during film formation were as shown in Table 1 under "TiAlCeN Layer Formation Conditions." The substrate temperature during film formation was 550°C, and the nitrogen gas flow rate was 900 sccm.

[0140] (Sample 12) Nitrogen gas was introduced into the chamber to create a reaction atmosphere of 3.5 Pa. While the substrate holder holding the substrate 2 was rotating, a pulsed arc was applied to the cathode made of the target material, causing an arc discharge that evaporated and ionized the target material. A TiAlCeN layer was then formed on the substrate 2, to which a constant negative bias voltage was applied, to obtain a cutting tool. The bias voltage, arc current, and pulse arc frequency during film formation were as shown in Table 1 under "TiAlCeN layer formation conditions." The substrate temperature during film formation was 600°C, and the nitrogen gas flow rate was 700 sccm.

[0141] Next, using the target for the first layer, nitrogen gas was introduced from the gas inlet, and the substrate holder was rotated to form the first layer (TiAlSiN layer) as a surface layer on the TiAlCeN layer, thereby obtaining a cutting tool.

[0142] (Sample 19) Nitrogen gas was introduced into the chamber to create an atmosphere of 3.5 Pa. In this state, an arc current was discharged on the surface of the target for the first layer, a bias voltage was applied to the substrate side, and the substrate holder was rotated to form the first layer (TiN layer) as a base layer on the surface of the substrate.

[0143] Next, a TiAlCeN layer was formed on the substrate under the same conditions as those for Sample 1 (reaction atmosphere, substrate temperature, bias voltage, arc current, pulse arc frequency, nitrogen gas flow rate), to obtain a cutting tool.

[0144] (Sample 1-1, Sample 1-3, Sample 1-8, Sample 1-9) Nitrogen gas was introduced into the chamber to create a reaction atmosphere of 3.5 Pa. While the substrate holder holding the substrate 2 was rotating, a constant arc was applied to the cathode made of the target material, causing an arc discharge that evaporated and ionized the target material. A constant negative bias voltage was then applied to the substrate 2, forming a TiAlCeN layer, resulting in a cutting tool. The substrate temperature during deposition was 550°C, the nitrogen gas flow rate was 1000 sccm, and the bias voltage and arc current were as shown in Table 1 under "TiAlCeN layer formation conditions."

[0145] (Sample 1-4) The target for the TiAlCeN layer and the target for the AlCrN layer were placed adjacent to each other in the chamber. Nitrogen gas was introduced into the chamber to create a reaction atmosphere of 3.5 Pa. While the substrate holder was rotating at 5 rpm, a constant arc was applied to the cathode made of the target material, causing an arc discharge and ionizing the target material. Then, TiAlCeN and AlCrN layers were alternately formed on the substrate 2 to which a constant negative bias voltage was applied, forming a multilayer coating and producing a cutting tool. During film formation, the substrate temperature was 450°C, the bias voltage was -100V, the arc current was 120A, and the nitrogen gas flow rate was 1000 sccm.

[0146] [Table 1]

[0147] <Evaluation> <Coating composition> Regarding the TiAlCeN layers of the cutting tools of each sample obtained, the composition of the first TiAlCeN layer located on the flank was Ti x1 Al y1 Ce z1N, the composition of the second TiAlCeN layer located on the rake face, Ti x2 Al y2 Ce z2 N, and the composition of the third TiAlCeN layer located at the cutting edge is Ti x3 Al y3 Ce z3 The N was measured. The specific measurement method is as shown in Embodiment 1 and Embodiment 2. The results are shown in Tables 2 and 3 in the "y1" and "z1" columns of the "first TiAlCeN layer," the "y2" and "z2" columns of the "second TiAlCeN layer," and the "y3" and "z3" columns of the "third TiAlCeN layer." Furthermore, the values ​​of "z3-z1" and "z3-z2" are also shown in Tables 2 and 3. It was confirmed that x1+y1+z1=1, x2+y2+z2=1, and x3+y3+z3=1 in all samples. Furthermore, the composition Ti of the first TiAlCeN layer was x1 Al y1 Ce z1 The total number of Ti, Al, and Ce atoms in N is A M1 Atomic number of N N1 Ratio A N1 / A M1 , the composition of the second TiAlCeN layer is Ti x2 Al y2 Ce z2 The total number of Ti, Al, and Ce atoms in N is A M2 Atomic number of N N2 Ratio A N2 / A M2 , and the composition of the third TiAlCeN layer is Ti x3 Al y3 Ce z3 The total number of Ti, Al, and Ce atoms in N is A M3 Atomic number of N N3 Ratio A N3 / A M3 was confirmed to be in the range of 0.8 to 1.2.

[0148] The thicknesses of the TiAlCeN layer, first layer, and total coating of the obtained cutting tools for each sample were measured. Specific measurement methods are as described in Embodiments 1 and 2. The results are shown in Tables 2 and 3 under "Thickness (μm)" as "TiAlCeN layer," "First layer (base layer)," "First layer (surface layer)," and "Total coating." The description "Multilayer structure (3.0 μm) TiAlCeN layer (6 nm) / AlCrN layer (6 nm)" for Sample 13 and Samples 1-4 indicates that the coating includes a multilayer structure in which 6-nm-thick TiAlCeN layers and 6-nm-thick AlCrN layers are alternately stacked, and that the total thickness of the multilayer structure is 3.0 μm.

[0149] The crystalline structure of the TiAlCeN layer of each cutting tool sample was measured, and it was confirmed that the TiAlCeN layer of all samples had a cubic crystalline structure.

[0150] <Cutting test> A cutting test was performed using each sample cutting tool under the following conditions, and the cutting distance (km) was measured until chipping occurred or the wear amount reached 0.2 mm. The longer the cutting distance, the longer the tool life of the cutting tool is judged to be. The results are shown in the "Distance (km)" column of "Cutting test" in Tables 2 and 3.

[0151] (Cutting conditions) Work material: SCM415 hardened steel round bar Cutting speed Vc:200m / min Feed rate f: 0.2 mm / rev Depth of cut ap: 0.2 mm Wet method The above cutting conditions correspond to high-efficiency machining of high-hardness materials.

[0152] [Table 2]

[0153] [Table 3]

[0154] <Consideration> The cutting tools of Samples 1 to 23 correspond to Examples. The cutting tools of Samples 1-1 to 1-9 correspond to Comparative Examples. It was confirmed that the cutting tools of Samples 1 to 23 (Examples) have longer tool life than the cutting tools of Samples 1-1 to 1-9 (Comparative Examples).

[0155] Although the embodiments and examples of the present disclosure have been described above, it is originally intended that the configurations of the above-described embodiments and examples may be appropriately combined or modified in various ways. The embodiments and examples disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the above-described embodiments and examples, and it is intended to include any modifications within the scope of the claims that are equivalent to the claims. [Explanation of symbols]

[0156] 1 cutting tools 2 Base material 2a Rake face 2b Flank 2c cutting edge 3 Coating 11. Rake face 12 Flank 13 Cutting edge 30 TiAlCeN layer 31 1st layer 32 Base layer 33 Surface layer

Claims

1. 1. A cutting tool comprising a substrate and a coating disposed on the substrate, The cutting tool comprises: Rake face, a flank surface connected to the rake surface; and a cutting edge formed by a boundary portion between the rake face and the flank face, the coating comprises a TiAlCeN layer; The TiAlCeN layer is a first TiAlCeN layer located on the flank surface; a second TiAlCeN layer located on the rake face; a third TiAlCeN layer located on the cutting edge; The composition of the first TiAlCeN layer is Ti ｘ１ Al ｙ１ Ce ｚ１ N, The composition of the second TiAlCeN layer is Ti ｘ２ Al ｙ２ Ce ｚ２ N, The composition of the third TiAlCeN layer is Ti ｘ３ Al ｙ３ Ce ｚ３ N, where: x1+y1+z1=1, x2+y2+z2=1, x3+y3+z3=1, 0.300<y1≦0.700, 0.300<y2≦0.700, 0.300<y3≦0.700, 0<z1≦0.090, 0<z2≦0.090, 0.010<z3≦0.100, z3-z1≧0.010, and A cutting tool, wherein z3-z2≧0.

010.

2. The cutting tool according to claim 1 , wherein the TiAlCeN layer has a thickness of 0.5 μm to 15 μm.

3. the coating further comprises a first layer; The first layer is at least one element selected from the first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum, and silicon of the periodic table; or 3. The cutting tool according to claim 1, comprising a first compound comprising at least one element selected from the first group and at least one element selected from a second group consisting of carbon, nitrogen, oxygen, and boron.

4. 4. The cutting tool of claim 3, wherein the first group consists of titanium, chromium, aluminum, and silicon.

5. 3. The cutting tool according to claim 1, wherein the coating has a thickness of 0.5 μm or more and 15 μm or less.

6. The cutting tool according to claim 3 , wherein the coating includes a multi-layer structure in which the TiAlCeN layers and the first layers are alternately stacked.

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