Cutting Tools

Abstract

A cutting tool comprises: a substrate and a coating arranged on the substrate, the coating comprising an α-Al2O3 layer composed of a plurality of α-Al2O3 particles, the average particle size a of the α-Al2O3 particles in a first region of the α-Al2O3 layer is greater than 0.10 μm and less than 0.30 μm, the average particle size b of the α-Al2O3 particles in a second region is greater than 0.30 μm and less than 0.50 μm, the average particle size c of the α-Al2O3 particles in a third region is greater than 0.50 μm and less than 1.50 μm, and b / a is greater than 1.5 and less than 5.0.

Description

Technical Field

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

[0002] Conventionally, cutting tools having a coating formed on a substrate have been used. Alumina having an α-type crystal structure (hereinafter also referred to as “α-Al 2 O 3 ”) has excellent mechanical properties and is therefore used as a coating material (Japanese Patent Application Publication No. 6-316758 (Patent Document 1), Japanese Patent Application Publication No. 2013-111720 (Patent Document 2)).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 6-316758

[0006] Patent Document 2: Japanese Patent Application Publication No. 2013-111720 Summary of the invention

[0007] The cutting tool disclosed herein has:

[0008] A substrate, and a coating disposed on the substrate,

[0009] The coating contains α-Al 2 O 3 layer,

[0010] The α-Al 2 O 3 The layer consists of multiple α-Al 2 O 3 Particle composition,

[0011] The α-Al 2 O 3 The layer includes the first area, the second area and the third area.

[0012] The first region is sandwiched between the α-Al 2 O 3 The region between the interface P1 on the substrate side of the layer and a virtual plane S1 at a distance of 0.5 μm from the interface P1 toward the surface side of the coating film,

[0013] The second region is a region sandwiched between the virtual surface S1 and a virtual surface S2 that is 1.0 μm away from the virtual surface S1 toward the surface side of the coating.

[0014] The third region is sandwiched between the α-Al 2 O 3 The surface of the layer P2 or the α-Al2 O 3 The region between the interface P3 on the surface side of the coating layer and a virtual plane S3 at a distance of 1.0 μm from the surface P2 or the interface P3 toward the substrate side,

[0015] The α-Al in the first region 2 O 3 The average particle size a of the particles is 0.10 μm or more and 0.30 μm or less.

[0016] The α-Al in the second region 2 O 3 The average particle size b of the particles is 0.30 μm or more and 0.50 μm or less.

[0017] The α-Al in the third region 2 O 3 The average particle size c of the particles is 0.50 μm or more and 1.50 μm or less.

[0018] The ratio b / a of a to b is 1.5 or more and 5.0 or less. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] [ Figure 1 ] Figure 1 This is a schematic diagram showing an example of a cross section of the cutting tool according to the first embodiment.

[0020] [ Figure 2 ] Figure 2 This is a schematic diagram showing another example of the cross section of the cutting tool according to the first embodiment.

[0021] [ Figure 3 ] Figure 3 This is a schematic diagram showing another example of the cross section of the cutting tool according to the first embodiment.

[0022] [ Figure 4 ] Figure 4 This is a schematic diagram showing another example of the cross section of the cutting tool according to the first embodiment.

[0023] [ Figure 5 ] Figure 5 To schematically illustrate α-Al 2 O 3 Figure 1 is an example of a backscattered electron image of a layer.

[0024] [ Figure 6 ] Figure 6 To illustrate the 2 O 3 Diagram showing a method for determining the average particle size of a layer.

[0025] [ Figure 7 ] Figure 7 To illustrate the 2 O 3 Diagram showing a method for determining the average particle size of a layer. DETAILED DESCRIPTION

[0026] [Problems to be Solved by the Present Disclosure]

[0027] In recent years, the load applied to the cutting edge of a tool tends to increase due to the difficulty of cutting materials and the demand for efficient machining. Therefore, a tool having a long tool life is required even in efficient machining of alloy steel.

[0028] Therefore, an object of the present disclosure is to provide a tool having a long tool life even in efficient machining of alloy steel.

[0029] [Effects of the present disclosure]

[0030] The cutting tool of the present disclosure can have a long tool life even in the high-efficiency machining of alloy steel.

[0031] [Description of Embodiments of the Present Disclosure]

[0032] First, embodiments of the present disclosure are listed and described.

[0033] (1) The cutting tool disclosed herein comprises:

[0034] A substrate, and a coating disposed on the substrate,

[0035] The coating contains α-Al 2 O 3 layer,

[0036] The α-Al 2 O 3 The layer consists of multiple α-Al 2 O 3 Particle composition,

[0037] The α-Al 2 O 3 The layer includes the first area, the second area and the third area.

[0038] The first region is sandwiched between the α-Al 2 O 3 The region between the interface P1 on the substrate side of the layer and a virtual plane S1 at a distance of 0.5 μm from the interface P1 toward the surface side of the coating film,

[0039] The second region is a region sandwiched between the virtual surface S1 and a virtual surface S2 that is 1.0 μm away from the virtual surface S1 toward the surface side of the coating.

[0040] The third region is sandwiched between the α-Al 2 O 3 The surface of the layer P2 or the α-Al 2 O 3 The region between the interface P3 on the surface side of the coating layer and a virtual plane S3 at a distance of 1.0 μm from the surface P2 or the interface P3 toward the substrate side,

[0041] The α-Al in the first region 2 O 3 The average particle size a of the particles is 0.10 μm or more and 0.30 μm or less.

[0042] The α-Al in the second region 2 O 3 The average particle size b of the particles is 0.30 μm or more and 0.50 μm or less.

[0043] The α-Al in the third region 2 O 3 The average particle size c of the particles is 0.50 μm or more and 1.50 μm or less.

[0044] The ratio b / a of a to b is 1.5 or more and 5.0 or less.

[0045] The cutting tool of the present disclosure can have a long tool life even in the high-efficiency machining of alloy steel.

[0046] (2) The average particle size c is preferably 0.50 μm or more and 1.20 μm or less. This improves the wear resistance of the cutting tool.

[0047] (3) The b / a is preferably 1.5 or more and 2.5 or less. This improves the adhesion between the first region and the second region, and improves the defect resistance.

[0048] (4) The α-Al 2 O 3 The average thickness of the layer is preferably 3 μm or more and 15 μm or less. This allows excellent wear resistance and defect resistance to be achieved at the same time.

[0049] (5) The α-Al 2 O 3 The TC(0 0 12) in the texture coefficient TC(hkl) of the layer is preferably not less than 3. This improves the wear resistance of the cutting tool.

[0050] [Detailed description of embodiments of the present disclosure]

[0051] When developing a tool having a long tool life even in efficient machining of alloy steel, the present inventors used conventional cutting tools described in Patent Documents 1 and 2 to perform efficient machining of alloy steel and observed the state of the tool after machining.

[0052] The wear loss is large in Patent Document 1. This is presumably because the grain size of the aluminum oxide layer in Patent Document 1 is relatively large, 0.5 μm to 3 μm.

[0053] The tool of Patent Document 2 tends to be easily defective. It is presumed that the reason for this is that, in Patent Document 2, the grain size of the lower side of the aluminum oxide layer is greatly different from the grain size of the surface side, and an interface between crystal grains is generated at the boundary between the lower side and the upper side, and this interface becomes the starting point of crack propagation.

[0054] Based on the above findings, the inventors have conducted in-depth research and have completed the cutting tool disclosed in the present invention, which has excellent wear resistance and defect resistance and has a long tool life. Hereinafter, a specific example of the cutting tool disclosed in the present invention will be described with reference to the accompanying drawings. In the drawings disclosed in the present invention, the same reference symbols represent the same parts or equivalent parts. In addition, in order to make the drawings clear and simple, the dimensional relationships such as length, width, thickness, and depth are appropriately changed, and do not necessarily represent the actual dimensional relationships.

[0055] In this specification, the expression of the form "A to B" refers to the upper and lower limits of a range (i.e., greater than A and less than B). When no unit is recorded for A and only the unit is recorded for B, the unit of A is the same as the unit of B.

[0056] In this specification, when a compound is represented by a chemical formula, when the atomic ratio is not particularly limited, it includes all atomic ratios known in the past, and should not be limited to the atomic ratio within the stoichiometric range. For example, when it is recorded as "TiCN", the ratio of the number of atoms constituting TiCN includes all atomic ratios known in the past.

[0057] [Embodiment 1: Cutting Tool]

[0058] A cutting tool according to one embodiment of the present disclosure (hereinafter also referred to as “this embodiment”) includes:

[0059] A substrate and a coating disposed on the substrate,

[0060] The coating contains α-Al 2 O 3 layer,

[0061] The α-Al 2 O 3 The layer consists of multiple α-Al 2 O 3Particle composition,

[0062] The α-Al 2 O 3 The layer includes the first area, the second area and the third area.

[0063] The first region is sandwiched between the α-Al 2 O 3 The region between the interface P1 on the substrate side of the layer and the virtual plane S1 at a distance of 0.5 μm from the interface P1 toward the surface side of the coating film,

[0064] The second region is a region sandwiched between the virtual surface S1 and a virtual surface S2 which is 1.0 μm away from the virtual surface S1 toward the surface side of the coating.

[0065] The third region is sandwiched between the α-Al 2 O 3 The surface of the layer P2 or the α-Al 2 O 3 The region between the interface P3 on the surface side of the coating layer and a virtual plane S3 at a distance of 1.0 μm from the surface P2 or the interface P3 toward the substrate side,

[0066] The α-Al in the first region 2 O 3 The average particle size a of the particles is 0.10 μm or more and 0.30 μm or less.

[0067] The α-Al in the second region 2 O 3 The average particle size b of the particles is 0.30 μm or more and 0.50 μm or less.

[0068] The α-Al in the third region 2 O 3 The average particle size c of the particles is 0.50 μm or more and 1.50 μm or less.

[0069] The ratio b / a of a to b is 1.5 or more and 5.0 or less.

[0070] The cutting tool of the present embodiment can have a long tool life even in the high-efficiency machining of alloy steel. The reason for this is not clear, but it is presumed to be the following (i) to (vi).

[0071] (i) In the cutting tool of this embodiment, α-Al 2 O 3 α-Al in the first region of the layer 2 O 3 The average particle size a of the particles (hereinafter also referred to as "the average particle size a of the first region") is as small as 0.10 μm or more and 0.30 μm or less.2 O 3 The layer is in contact with the α-Al 2 O 3 The layer on the substrate side of the layer (hereinafter also referred to as "underlying layer"), or the layer in contact with the α-Al 2 O 3 The adhesion between the substrates of the layers is large. Therefore, it is difficult to produce α-Al 2 O 3 The crack propagates starting from the interface between the first layer and the lower layer or the substrate, so that the cutting tool has excellent defect resistance. In addition, when the average grain size a of the first region is within the above range, the resistance to weld separation is improved.

[0072] (ii) In the cutting tool of this embodiment, α-Al 2 O 3 The average particle size a of the first region of the layer is different from the average particle size a of the α-Al 2 O 3 The difference in the average particle size b of the particles (hereinafter also referred to as "the average particle size b of the second region") is small, and the average particle size b of the second region is similar to that of the α-Al in the third region. 2 O 3 The difference in the average particle size c of the particles (hereinafter also referred to as "the average particle size c of the third region") is small. Therefore, the interface generated due to the difference in particle size between the first region and the second region and between the second region and the third region is suppressed. 2 O 3 In the layer, the generation of interfaces that serve as crack starting points is suppressed, so the adhesion between the first region, the second region, and the third region is increased, and the cutting tool has excellent defect resistance.

[0073] (iii) In the cutting tool of this embodiment, the α-Al 2 O 3 In the layer, α-Al 2 O 3 The particle size increases gradually from the substrate side to the tool surface side. Therefore, the crack propagation distance from the tool surface becomes longer, which suppresses the α-Al 2 O 3 Further, the cracks on the substrate side of the α-Al 2 O 3 The grain size of the third region on the tool surface side of the layer is 0.50 μm or more and 1.50 μm or less, so that the propagation of cracks starting from the tool surface is suppressed. Therefore, the cutting tool has excellent defect resistance.

[0074] (iv) In the cutting tool of this embodiment, α-Al 2 O 3Since the average grain size c of the third region of the layer is 0.50 μm or more and 1.50 μm or less, the cutting tool has excellent wear resistance.

[0075] (v) In the cutting tool of this embodiment, α-Al 2 O 3 The ratio b / a of the average particle size a in the first region of the layer to the average particle size b in the second region is 1.5 or more, and the average particle size b is larger than the average particle size a. Therefore, in the first region and the second region, cracks are difficult to propagate in the thickness direction of the coating, so that the cutting tool has excellent defect resistance. In addition, b / a is less than 5, and the difference between the average particle size a and the average particle size b is small, so the interface caused by the particle size difference is suppressed. 2 O 3 In the layer, the generation of an interface which serves as a crack starting point is suppressed, so the adhesion between the first region and the second region is increased, and the cutting tool has excellent defect resistance.

[0076] (vi) As described in (i) to (v) above, the cutting tool of the present embodiment has excellent chipping resistance and wear resistance, and can have a long tool life even in high-efficiency machining of alloy steel.

[0077] <Cutting tool structure>

[0078] like Figure 1 As shown, the cutting tool 1 of this embodiment includes a substrate 10 and a coating 15 disposed on the substrate 10. The coating 15 includes α-Al 2 O 3 Layer 11. The coating 15 preferably covers at least a portion of the cutting portion of the rake face of the substrate, preferably covers at least a portion of the cutting portion of the substrate, and more preferably covers the entire surface of the substrate. The cutting portion of the substrate refers to an area within 1.5 mm from the cutting edge line on the substrate surface. Even if a portion of the substrate is not covered by the coating, or the composition of the coating is partially different, it does not depart from the scope of the present disclosure.

[0079] <Application of cutting tools>

[0080] The cutting tools disclosed herein may be, for example, drills, end mills (e.g., ball end mills), indexable cutting inserts for drills, indexable cutting inserts for end mills, indexable cutting inserts for milling, indexable cutting inserts for turning, metal saws, gear cutting tools, reamers, taps, etc.

[0081] <Base material>

[0082] The substrate 10 includes a rake face and a flank face, and any substrate can be used as the substrate as long as it is a conventionally known substrate. For example, it is preferably any one of cemented carbide (for example, WC-CO cemented carbide and other WC-based cemented carbide, which may contain carbonitrides of Ti, Ta, Nb, etc.), cermet (materials with TiC, TiN, TiCN, etc. as main components), high-speed steel, ceramic (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, etc.), cubic boron nitride sintered body, or diamond sintered body.

[0083] Among these various substrates, cemented carbide (especially WC-based cemented carbide) or cermet (especially TiCN-based cermet) is preferably selected. These substrates have excellent balance between hardness and strength at high temperatures, so that they have excellent properties as the substrate of the cutting tool for the above-mentioned purpose. When using WC-based cemented carbide as the substrate, its texture may contain free carbon and abnormal layers such as η phase or ε phase.

[0084] The surface of the substrate may also be modified. For example, in the case of cemented carbide, a de-β layer may be formed on the surface; or in the case of cermet, a surface hardening layer may be formed. Even if the surface of the substrate is modified, the desired effect can be achieved.

[0085] In the case where the cutting tool is an indexable cutting insert, etc., the substrate may or may not have a chip breaker. The shape of the cutting edge ridgeline portion may be any of the following shapes: a sharp edge (a ridge formed by the intersection of the front cutting surface and the back cutting surface), a honed edge (a shape obtained by giving a rounded corner to the sharp edge), a negative land (a chamfered shape), or a shape obtained by combining a honed edge and a negative land.

[0086] <Lamination>

[0087] The coating contains α-Al 2 O 3 For example, the coating may include one or more layers of α-Al 2 O 3 layer, and further composed of a plurality of layers including other layers.

[0088] In addition to α-Al 2 O 3 In addition to the layer 11, the coating 15 may also include other layers. Figure 2 As shown in the cutting tool 21, the coating 25 may further include a coating disposed between the substrate 10 and the α-Al 2 O 3 A lower bottom layer 12 is provided between the layers 11.

[0089] like Figure 3As shown in the cutting tool 31, in addition to the lower base layer 12, the coating 35 may also include a coating layer disposed on the α-Al 2 O 3 A surface layer 13 is provided on the layer 11.

[0090] like Figure 4 As shown in the cutting tool 41, in addition to the lower bottom layer 12 and the surface layer 13, the coating 45 may further include a layer disposed between the lower bottom layer 12 and the α-Al 2 O 3 The intermediate layer 14 is provided between the layers 11. The details of the lower layer, the surface layer and the intermediate layer will be described later.

[0091] The average thickness of the entire coating disposed on the substrate is preferably 3 μm to 30 μm. This allows the coating to have excellent wear resistance and peeling resistance. The average thickness of the coating is more preferably 5 μm to 25 μm, and even more preferably 8 μm to 20 μm.

[0092] The thickness of the coating is measured, for example, by obtaining a cross-sectional sample parallel to the normal direction of the surface of the substrate and observing the sample using a scanning transmission electron microscope (STEM). Examples of the scanning transmission electron microscope include JEM-2100F (trade name) manufactured by "JEOL Ltd."

[0093] When "thickness" is mentioned in this specification, the thickness refers to the average thickness. Specifically, the observation magnification of the cross-section sample is set to 5000 times, and a rectangular measurement field of (30 μm in the direction parallel to the substrate surface) × (the distance including the overall thickness of the coating) is set in the electron microscope image, and the thickness dimensions at 10 locations in the field of view are measured, and the average value is set as "thickness". The thickness and average thickness of the lower layer, intermediate layer and surface layer described below are also measured and calculated in the same manner.

[0094] It is to be noted that it has been confirmed that, in the same sample, even if a plurality of measurement fields including the coating on the rake face or the coating on the flank face are arbitrarily selected and the above-mentioned measurement is performed in the measurement fields to calculate the above-mentioned average thickness, the same result can be obtained.

[0095] <α-Al 2 O 3 Layer>

[0096] (α-Al 2 O 3 Layer composition)

[0097] In this embodiment, α-Al 2O 3 The layer consists of multiple α-Al 2 O 3 (alumina with α-type crystal structure) particles. 2 O 3 The layer is made of polycrystalline α-Al 2 O 3 As long as the effect of this embodiment can be exerted, α-Al 2 O 3 The layer may contain inevitable impurities, etc. That is, as long as the effects of the present disclosure are not impaired, α-Al 2 O 3 The layer contains other ingredients.

[0098] In this embodiment, the α-Al disposed on the rake face of the substrate 10 2 O 3 The layer 11 includes a first region A1, a second region A2, and a third region A3. In this specification, the first region A1, the second region A2, and the third region A3 are defined as the following regions.

[0099] The first region A1 is sandwiched between α-Al 2 O 3 The region between the interface P1 on the substrate 10 side of the layer 11 and the virtual surface S1 at a distance of 0.5 μm from the interface P1 to the surface P2 side of the coating 15. Here, the interface P1 is included in the first region A1, but the virtual surface S1 is not included in the first region A1.

[0100] The second region A2 is a region sandwiched between the virtual surface S1 and the virtual surface S2 which is 1.0 μm away from the virtual surface S1 toward the surface P2 of the coating 15. Here, the virtual surface S1 and the virtual surface S2 are included in the second region A2.

[0101] In the α-Al 2 O 3 When the layer 11 is disposed on the outermost surface of the coating (for example, Figure 1 and Figure 2 ), the third region A3 is sandwiched between α-Al 2 O 3 The region between the surface P2 of the layer 11 and the virtual surface S3 which is 1.0 μm away from the surface P2 toward the substrate side. Here, the surface P2 and the virtual surface S3 are included in the third region A3.

[0102] In α-Al 2 O 3 When other layers (surface layers) are arranged on layer 11 (for example, Figure 3 and Figure 4 ), the third region A3 is sandwiched between α-Al 2 O3 The region between the interface P3 on the surface side of the coating film of the layer 11 and the virtual surface S3 which is 1.0 μm away from the interface P3 toward the substrate 10. Here, the interface P3 and the virtual surface S3 are included in the third region A3.

[0103] The second region and the third region may be in contact with each other. In addition, another region may be arranged between the second region and the third region. In this case, the other region is a region sandwiched between the virtual surface S2 and the virtual surface S3.

[0104] (α-Al 2 O 3 Average particle size

[0105] In this embodiment, the α-Al in the first region 2 O 3 The average particle size a of the particles is 0.10 μm or more and 0.30 μm or less, and the α-Al in the second region 2 O 3 The average particle size b of the particles is 0.30 μm or more and 0.50 μm or less. The α-Al 2 O 3 The average particle size c of the particles is 0.50 μm or more and 1.50 μm or less, and the ratio b / a of a to b is 1.5 or more and 5.0 or less.

[0106] When the α-Al in the first region 2 O 3 When the average particle size a of the particles is 0.10 μm or more and 0.30 μm or less, α-Al 2 O 3 The layer is in contact with the α-Al 2 O 3 The substrate side of the layer or the layer in contact with the α-Al 2 O 3 The adhesion between the substrates of the layers is increased. Therefore, it is difficult to produce α-Al 2 O 3 The crack propagation starting from the interface between the layer and the lower layer or substrate is excellent in the defect resistance of the cutting tool. From the viewpoint of improving the adhesion and defect resistance, the average particle size a is preferably 0.12 μm to 0.28 μm, more preferably 0.14 μm to 0.26 μm, and further preferably 0.16 μm to 0.24 μm.

[0107] When the α-Al in the second region 2 O 3When the average particle size b of the particles is 0.30 μm or more, crack propagation from the tool surface can be suppressed, thereby improving the defect resistance. On the other hand, when the average particle size b is 0.50 μm or less, due to the interaction with the α-Al 2 O 3 The difference in average particle size a between the particles is small, so the interface generated by the difference in particle size between the first region and the second region can be suppressed. Therefore, it is difficult for cracks to propagate starting from the interface, and the decrease in the adhesion between the first region and the second region is suppressed, so that the cutting tool can have excellent defect resistance. 2 O 3 The average particle size b of the particles is related to the α-Al 2 O 3 The difference in the average particle size c of the particles is small, so the interface generated by the difference in particle size between the second region and the third region can be suppressed. Therefore, it is difficult to generate crack propagation starting from the interface, and the reduction in the adhesion between the second region and the third region is suppressed, so that the cutting tool can have excellent defect resistance. From the viewpoint of improving adhesion and defect resistance, the average particle size b is preferably 0.32 μm or more and 0.48 μm or less, more preferably 0.34 μm or more and 0.46 μm or less, and further preferably 0.36 μm or more and 0.44 μm or less.

[0108] When the α-Al in the third region 2 O 3 When the average particle size c of the particles is 0.50 μm or more, crack propagation from the tool surface is suppressed, so that the cutting tool can have excellent defect resistance. When the average particle size c is 1.50 μm or less, the wear resistance of the cutting tool is improved. The average particle size c is preferably 0.50 μm or more and 1.20 μm or less, more preferably 0.70 μm or more and 1.20 μm or less, and further preferably 0.90 μm or more and 1.10 μm or less.

[0109] The ratio b / a of the average particle size a to the average particle size b is 1.5 or more and 5.0 or less. When the ratio b / a is 1.5 or more, the average particle size b is larger than the average particle size a, and cracks are difficult to expand in the thickness direction of the first region and the second region, so that the cutting tool has excellent defect resistance. In addition, when b / a is 5.0 or less, since the difference between the average particle size a and the average particle size b is small, the adhesion between the first region and the second region is improved, and the generation of cracks at the first region and the second region is suppressed. Therefore, the cutting tool has excellent wear resistance.

[0110] In this specification, the average particle diameter a, the average particle diameter b, and the average particle diameter c are measured by the following procedures (A1) to (A8).

[0111] (A1) Cut the cutting tool along the normal line of the rake face of the substrate using diamond wire to make the α-Al 2 O 3 The cross section of the layer is exposed. The exposed cross section is ion milled using Ar ions to make the cross section mirror-finished. The conditions for this ion milling are as follows.

[0112] Accelerating voltage: 6kV

[0113] Irradiation angle: In α-Al 2 O 3 In the cross section of the layer, the distance from α-Al 2 O 3 The thickness direction of the layer is parallel to the straight line direction 0°

[0114] Irradiation time: 6 hours

[0115] (A2) A cross section of the mirror surface state was observed at 5000 times using a field emission scanning electron microscope (EF-SEM) to obtain a backscattered electron image (EBSD). Figure 5 This is a diagram schematically showing an example of EBSD.

[0116] (A3) In the above EBSD, it is determined that α-Al 2 O 3 The measurement range is set to include the region where the difference D1 between the valley bottom B1 and the peak T1 of the interface P1 on the substrate side of the layer in the normal direction along the rake face is 0.5 μm or less. The measurement range is set to a rectangle of (transverse direction (direction parallel to the rake face): 30 μm) × (vertical direction (normal direction of the rake face): length including the entire coating).

[0117] (A4) In the above-mentioned measurement range, a reference line LS1 is set at a midpoint between the valley bottom B1 and the peak top T1 of the interface P1.

[0118] (A5) The α-Al 2 O 3 The lateral particle size of the particles. 2 O 3 The particle sizes of the particles were measured, and the average value was taken as the α-Al 2 O 3 The average particle size a.

[0119] (A6) The α-Al 2 O 3The lateral particle size of the particles. 2 O 3 The particle sizes of the particles were measured, and the average value was taken as the α-Al 2 O 3 The average particle size b.

[0120] (A7) In the above measurement range, when α-Al 2 O 3 When the layer is disposed on the outermost surface of the coating, it is aligned with the α-Al 2 O 3 The α-Al 2 O 3 The lateral particle size of the particle; or in α-Al 2 O 3 When a surface layer is disposed on the layer, the surface layer is disposed on the substrate in the direction of the α-Al 2 O 3 The interface P3 (α-Al 2 O 3 The α-Al 2 O 3 The lateral particle size of the particles. 2 O 3 The particle sizes of the particles were measured, and the average value was taken as the α-Al 2 O 3 Average particle size c of particles. When the surface P2 and the interface P3 have projections and depressions, the line L3 is set at a position 0.6 μm away from a line passing through the valley bottom closest to the substrate in the measurement range and parallel to the reference line LS1 in the substrate direction.

[0121] (A8) Within the above measurement range, the α-Al content is measured on a line L4 that passes through the midpoint of the normal direction of the rake face of the fourth region and is parallel to the rake face. 2 O 3 The lateral particle size of the particles. 2 O 3 The particle sizes of the particles were measured, and the average value was taken as the α-Al 2 O 3 The average particle size d.

[0122] In the above (A5), the difference between the bottom of the interface B1 and the top of the interface T1 is large (for example, 0.5 μm). Figure 6 As shown, in the case where the line L1 exists inside the substrate, inside the substrate (for example, by Figure 6 α-Al is not formed on line L1 (the area indicated by X in FIG. 2 O 3 The particle size of the particles is only determined in α-Al 2 O 3 α-Al 2 O 3 The particle size of the particles was measured and the average particle size a was calculated.

[0123] When setting the above line L1, if Figure 7 As shown, the inventors set lines La1 to Ld1 passing through positions with an interval of 0.1 μm in the range of 0.1 μm or more and less than 0.5 μm from the reference line LS1 in the normal direction of the rake face in the first region, and measured all α-Al in the measurement range on each line and on the interface S1. 2 O 3 The particle sizes of the particles were measured and the average values ​​were calculated. The results confirmed that when the average particle size on line Lb1 corresponding to line L1 was 0.10 μm or more and 0.30 μm or less, the average particle size on lines La1 to Ld1 and interface S1 was also 0.10 μm or more and 0.30 μm or less. It is presumed that the reason for this is that the orientation and concavity of the bottom are greatly affected in the initial stage of nucleation, so Al 2 O 3 The crystals grow not in a columnar shape (or a state where the cross-sectional grain size increases toward the surface) but in a granular shape (with equal degrees of verticality / parallelism to the interface).

[0124] It has been confirmed that even if different measurement ranges are arbitrarily selected for the same cutting tool and the above measurement is performed within the measurement range, the same result can be obtained. It has been further confirmed that even if different measurement ranges are arbitrarily selected for different cutting tools and the above measurement is performed within the measurement range, the same result can be obtained. Therefore, the average particle size on line L1 of 0.10 μm or more and 0.30 μm or less means that the α-Al in the first region 2 O 3 The average particle size a of the particles is 0.10 μm or more and 0.30 μm or less.

[0125] When setting the above line L2, if Figure 7 As shown, the inventors set lines La2 to Lf2 passing through positions with an interval of 0.2 μm in the range of 0.5 μm to 1.5 μm from the reference line LS1 in the normal direction of the rake face in the second region, and measured all α-Al in the measurement range on each line. 2 O 3The particle size of the particles is measured and the average value of these is calculated. The result confirms that when the average particle size on the line Ld2 corresponding to the line L2 is 0.30 μm or more and 0.50 μm or less, the average particle size on the line La2 to the line Lf2 is also 0.30 μm or more and 0.50 μm or less. The reason is speculated as follows. The second region is a transition region from nucleation to crystal growth. In the first region, in addition to the gas conditions, nucleation is also caused by the influence of the orientation, concavity, etc. of the lower bottom, but in the second region, the influence of the gas conditions is dominant, and the nuclei (orientation, shape, etc.) different from those in the first region are dominant. It is speculated that the crystals produced by nucleation are eliminated, and on the other hand, stable nuclei are generated under new gas conditions, so the overall number of particles will not change significantly, and the change in particle size is not large. In addition, in the present disclosure, by adjusting the gas conditions when the first and second regions are formed, the elimination and nucleation of crystals are smoothly transitioned, thereby expanding the second region in the thickness direction and maintaining the particle size.

[0126] It has been confirmed that even if different measurement ranges are arbitrarily selected in the same cutting tool and the above measurement is performed within the measurement range, the same result can be obtained. It has been further confirmed that even if different measurement ranges are arbitrarily selected in different cutting tools and the above measurement is performed within the measurement range, the same result can be obtained. Therefore, the average particle size on line L2 of 0.30 μm or more and 0.50 μm or less means that the α-Al in the second region 2 O 3 The average particle size b of the particles is 0.30 μm or more and 0.50 μm or less.

[0127] When the above line L3 is set, Figure 7 As shown, the inventors have found that the distance α-Al in the normal direction of the rake face in the third region is 2 O 3 The surface of the layer P2, or α-Al 2 O 3 In the range of 0 μm to 1.0 μm, lines La3 to Lf3 passing through positions with an interval of 0.2 μm are set, and all α-Al in the measurement range are measured on each line. 2 O 3 The particle sizes of the particles were measured and the average values ​​thereof were calculated. The results confirmed that when the average particle size on line Ld3 corresponding to line L3 was 0.50 μm or more and 1.50 μm or less, the average particle sizes on lines La3 to Lf3 were also 0.50 μm or more and 1.50 μm or less. It is presumed that the reason for this is that the third region is a complete crystal growth region and the number of crystals changes little.

[0128] It has been confirmed that even if different measurement ranges are arbitrarily selected for the same cutting tool and the above measurement is performed within the measurement range, the same result can be obtained. It has been further confirmed that even if different measurement ranges are arbitrarily selected for different cutting tools and the above measurement is performed within the measurement range, the same result can be obtained. Therefore, the average particle size on line L3 of 0.50 μm or more and 1.50 μm or less means that the α-Al in the third region 2 O 3 The average particle size c of the particles is 0.50 μm or more and 1.50 μm or less.

[0129] It has been confirmed that in cutting tools, the α-Al 2 O 3 The average particle size a of the particles is 0.10 μm or more and 0.30 μm or less, and the α-Al in the second region 2 O 3 The average particle size b of the particles is 0.30 μm or more and 0.50 μm or less, and the α-Al in the third region 2 O 3 When the average particle size c of the particles is 0.50 μm or more and 1.50 μm or less and the ratio b / a of a to b is 1.5 or more and 5.0 or less, even if the distance between the line L2 and the line L3 changes, there is no influence on the effect.

[0130] In view of the above, the cutting tool of the present embodiment can also be expressed as follows.

[0131] The cutting tool disclosed herein has:

[0132] A substrate, and a coating disposed on the substrate,

[0133] The coating contains α-Al 2 O 3 layer,

[0134] The α-Al 2 O 3 The layer consists of multiple α-Al 2 O 3 Particle composition,

[0135] In a cross section along the normal line of the surface of the coating,

[0136] From the substrate and the α-Al 2 O 3 The reference line LS1 is based on the interface of the layer to the α-Al 2 O 3 The α-Al on the line L1 at a distance of 0.2 μm from the layer side 2 O 3 The average particle size a of the particles is 0.10 μm or more and 0.30 μm or less.

[0137] From the base line LS1 to the α-Al 2 O 3 The α-Al on the line L2 at a distance of 1.1 μm from the layer side 2 O 3 The average particle size b of the particles is 0.30 μm or more and 0.50 μm or less.

[0138] From the α-Al 2 O 3 The surface P2 of the layer, or the α-Al 2 O 3 The interface P3 on the surface side of the coating layer is oriented toward the α-Al 2 O 3 α-Al on line L3 at a distance of 0.6 μm from the layer side 2 O 3 The average particle size c of the particles is 0.50 μm or more and 1.50 μm or less.

[0139] The ratio b / a of a to b is 1.5 or more and 5.0 or less.

[0140] (b / a)

[0141] In the cutting tool of this embodiment, α-Al 2 O 3 The ratio b / a of the average particle size a in the first region of the layer to the average particle size b in the second region is 1.5 or more and 5.0 or less. b / a is 1.5 or more, and the average particle size b is larger than the average particle size a, so that cracks are difficult to expand in the thickness direction of the first region and the second region, so that the cutting tool has excellent defect resistance. In addition, b / a is 5 or less, and the difference between the average particle size a and the average particle size b is small, so the adhesion between the first region and the second region is improved, and cracks are suppressed in the first region and the second region. Therefore, the cutting tool has excellent wear resistance.

[0142] From the viewpoint of improving the adhesion between the first region and the second region and improving the defect resistance, b / a is 1.5 to 5.0, preferably 1.5 to 2.5, more preferably 1.7 to 2.3, and further preferably 1.9 to 2.1.

[0143] (Texture coefficient)

[0144] In the present disclosure, in the texture coefficient TC(hkl) represented by the following formula (1), α-Al 2 O 3 The TC (0 0 12) of the layer is preferably 3 or more. 2 O 3The layer can have excellent wear resistance. Therefore, the cutting tool can have a long tool life.

[0145] [Mathematical formula 1]

[0146]

[0147] In formula (1), I(hkl) represents the X-ray diffraction intensity of the (hkl) reflection surface, I 0 (h kl) represents the standard intensity of the ICDD PDF card number 00-010-0173. In addition, n in formula (1) represents the number of reflections used in the calculation, and in this embodiment, it is 8. The (hkl) planes used for reflection are (0 1 2), (1 0 4), (1 1 0), (0 0 12), (1 1 3), (02 4), (1 16), and (3 0 0).

[0148] ICDD (registered trademark) is the abbreviation of International Centre for Diffraction Data, and PDF (registered trademark) is the abbreviation of Powder Diffraction File.

[0149] It should be noted that the α-Al 2 O 3 TC(0 0 12) of the layer can be expressed by the following formula (2).

[0150] [Mathematical formula 2]

[0151]

[0152] Therefore, “in the texture coefficient TC(hkl), TC(0 0 12) is 3 or more” means that the value obtained by the above formula (2) obtained by substituting TC(0 0 12) into the above formula (1) is 3 or more.

[0153] The value of TC (0 0 12) is more preferably 4 or more, and further preferably 5 or more. The larger the value of TC (0 0 12), the more effectively the wear resistance can be improved. There is no upper limit to the value of TC (0 0 12), but since there are 8 reflecting surfaces used in the calculation, it is sufficient to set it to 8 or less. The value of TC (0 0 12) can be set to 3 or more and 8 or less, 4 or more and 8 or 5 or more and 8 or less.

[0154] In the present disclosure, in the texture coefficient TC(hkl) shown in the above formula (1), α-Al 2 O 3The TC (1 1 0) of the layer is preferably 2 or more. 2 O 3 The layer can have excellent defect resistance. Therefore, the cutting tool can have a long tool life.

[0155] It should be noted that the α-Al 2 O 3 TC(1 1 0) of the layer can be expressed by the following formula (3).

[0156] [Mathematical formula 3]

[0157]

[0158] Therefore, “in the texture coefficient TC(hkl), TC(1 1 0) is 2 or more” means that the value obtained by substituting TC(1 1 0) into the above formula (1) is 2 or more.

[0159] The value of TC (1 1 0) is more preferably 2.5 or more, and further preferably 3 or more. The larger the value of TC (1 1 0), the more effectively the defect resistance can be improved. There is no upper limit to the value of TC (1 1 0), but since there are 8 reflective surfaces used in the calculation, it can be set to 8 or less. The value of TC (1 1 0) can be set to 2 or more and 8 or less, 2.5 or more and 8 or more, or 3 or more and 8 or less.

[0160] The measurement of TC (hkl) as described above can be performed by analysis using an X-ray diffraction device. TC (hkl) can be measured, for example, using SmartLab (registered trademark) manufactured by "Rigaku Corporation" (scanning speed: 21.7 ° / min, step length (step): 0.01 °, scanning range: 15 ~ 140 °) under the following conditions. It should be noted that in this embodiment, the result of measuring TC (hkl) using an X-ray diffraction device is referred to as "XRD result".

[0161] Characteristic X-ray: Cu-Kα

[0162] Tube voltage: 45kV

[0163] Tube current: 200mA

[0164] Filter: Multilayer mirror

[0165] Optical system: focusing method

[0166] X-ray diffraction method: θ-2θ method

[0167] When using an X-ray diffraction device, X-rays are irradiated to the back face of the cutting tool. Usually, the front face is formed with bumps and depressions, while the back face is flat, so in order to eliminate interference factors, it is preferred to irradiate the back face with X-rays. In particular, X-rays are irradiated at a position on the back face that extends about 2 to 4 mm from the cutting edge. As a result, the reproducibility of the results is improved. It should be noted that in this embodiment, the α-Al on the back face of the substrate 2 O 3 The TC(hkl) value of the layer is related to the α-Al 2 O 3 The values ​​of TC(hkl) of the layers are the same.

[0168] It is to be noted that it has been confirmed that the same result can be obtained even if a plurality of measurement positions are arbitrarily selected in the same sample and the above-mentioned measurement is performed at each measurement position.

[0169] (thickness)

[0170] α-Al 2 O 3 The average thickness of the layer is preferably 3 μm or more and 15 μm or less. This allows for excellent wear resistance and defect resistance. 2 O 3 The lower limit of the average thickness of the layer is preferably 3 μm or more, more preferably 4 μm or more, and further preferably 5 μm or more. 2 O 3 When the average thickness of the layer is less than 3 μm, the above-mentioned α-Al 2 O 3 From the viewpoint of improving the defect resistance, the α-Al 2 O 3 The upper limit of the average thickness of the layer is preferably 15 μm or less, preferably 10 μm or less, more preferably 9 μm or less, and further preferably 8 μm or less. 2 O 3 The average thickness of the layer is preferably 3 μm to 10 μm, more preferably 4 μm to 9 μm, and even more preferably 5 μm to 8 μm.

[0171] As mentioned above, α-Al 2 O 3 The thickness of the layer can be confirmed by observing a cross-section sample of the cutting tool using a scanning transmission electron microscope (STEM) or the like. 2 O 3 The particle size is the measurement range that is set.

[0172] It is to be noted that it was confirmed that similar results can be obtained even when a plurality of measurement ranges including the coating on the rake face or the coating on the flank face are arbitrarily selected for the same sample and the above-mentioned measurement is performed for each measurement range.

[0173] <Other floors>

[0174] As mentioned above, except for α-Al 2 O 3 In addition to the layer, the coating may also contain other layers. Figure 2 to Figure 4 As shown, other layers include an underlayer 12, a surface layer 13, an intermediate layer 14, and the like.

[0175] (Lower Ground Floor)

[0176] The lower layer is arranged between the substrate and the α-Al 2 O 3 The lower layer may be a TiN layer, for example. The average thickness of the TiN layer is preferably 0.1 μm to 20 μm. Thus, the coating can have excellent wear resistance and defect resistance.

[0177] (Surface layer)

[0178] As the surface layer, for example, it is preferred that any one of Ti (titanium) carbide, nitride or boride is used as the main component. The surface layer is a layer arranged on the outermost side of the coating. However, there are cases where the surface layer is not formed on the cutting edge line. For example, the surface layer is arranged on the α-Al 2 O 3 Just above the layer.

[0179] “Main component: any one of carbides, nitrides, and borides of Ti” means any one of carbides, nitrides, and borides of Ti containing 90% by mass or more. In addition, this means that it is preferably composed of any one of carbides, nitrides, and borides of Ti, excluding unavoidable impurities.

[0180] Among any of Ti carbides, nitrides and carbonitrides, it is particularly preferred that the surface layer be composed mainly of Ti nitrides (i.e., compounds represented by TiN). TiN has the clearest color (golden) among these compounds, and therefore has the advantage of being easy to identify the tip of the cutting blade after cutting (identify the used part). The surface layer is preferably composed of a TiN layer.

[0181] The average thickness of the surface layer is preferably 0.05 μm or more and 1 μm or less. Thus, the adhesion between the surface layer and the adjacent layer is improved. The upper limit of the average thickness of the surface layer can be set to 0.8 μm or less and 0.6 μm or less. The lower limit of the average thickness can be set to 0.1 μm or more and 0.2 μm or more.

[0182] <Middle layer>

[0183] The middle layer is arranged between the lower layer and the α-Al 2 O 3 As the intermediate layer, for example, a TiCN layer and a TiCNO layer can be cited. Since the TiCN layer and the TiCNO layer have excellent wear resistance, the coating can be given more suitable wear resistance. The average thickness of the intermediate layer is preferably 1 μm to 20 μm. Here, the average thickness of the intermediate layer refers to: when the intermediate layer is formed by more than two layers, the average of the total thickness of the two layers or more.

[0184] [Embodiment 2: Method for manufacturing cutting tool]

[0185] The cutting tool of the first embodiment can be manufactured by forming a coating on a substrate by chemical vapor deposition (CVD). 2 O 3 In the case of other layers other than the layer, the other layers can be formed by using a chemical vapor deposition apparatus under conventionally known conditions. 2 O 3 The layer can be formed, for example, by the following method. It should be noted that the cutting tool of the first embodiment is not limited to being produced by the following production method, and may be produced by other production methods.

[0186] α-Al 2 O 3 The film forming conditions of the layer can be set, for example, as follows: temperature 950-1050°C, pressure 10-50 hPa, gas flow rate (total gas flow rate) 50-100 L / min. "Total gas flow rate" means the total volume flow rate introduced into the CVD furnace per unit time when the gas under standard conditions (0°C, 1 atmosphere) is set as an ideal gas.

[0187] Using AlCl 3 , HCl, CO 2 , H 2 S and H 2 As raw material gas. 2 O 3 The change in the thickness of the layer changes the amount of HCl contained in the raw material gas. Specifically, it is as follows.

[0188] From film formation to α-Al 2 O 3 The thickness of the layer is less than 0.5 μm, and the raw material gas composition is set to: HCl: 7.5 volume % or more and 9 volume % or less, AlCl 3 : 2 volume % or more and 5 volume % or less, CO 2 : 0.1 volume % or more and 6 volume % or less, H 2 S: 0.1 volume % or more and 1 volume % or less, and H 2 : The remaining volume % when the entire raw material gas is assumed to be 100 volume %. Thus, the first region is formed.

[0189] Then, until α-Al 2 O 3 The thickness of the layer is 0.5 μm or more and 1.5 μm or less. The raw material gas is formulated as follows: HCl: 6 volume % or more and less than 7.5 volume %. Compared with the case where the first region is formed, the amount of HCl in the raw material gas is reduced. 2 The amount of increase is the same as when the other gases are combined to form the first area. Thus, the second area is formed.

[0190] Then, until the α-Al 2 O 3 The same raw material gas as that of the second region was used until the final thickness of the layer was less than 1.0 μm.

[0191] Next, from the ratio of α-Al 2 O 3 The final thickness of the layer is less than 1.0 μm until the thickness of α-Al 2 O 3 The surface of the layer is formed by setting the raw material gas to be composed of: HCl: 2.8 volume % or more and less than 6 volume %, and the HCl in the raw material gas is reduced by a certain amount compared with when the second region is formed. 2 The amount of increase is the same as that of the other gases in forming the second area. Thus, the third area is formed.

[0192] Conventionally, HCl was used to suppress the excessive generation of α-Al during film formation. 2 O 3 and form α-Al in the gas phase 2 O 3 When α-Al is formed in the gas phase 2 O 3 It is difficult to form α-Al particles on the substrate. 2 O 3On the other hand, it is believed that when the amount of HCl in the raw material gas is large, the film forming speed decreases. Therefore, it is common technical knowledge to set the amount of HCl in the raw material gas to the minimum required limit, and those skilled in the art do not have a technical idea to increase the amount of HCl in the raw material gas.

[0193] Compared with the conventional technical common sense, in this embodiment, as described above, the amount of HCl is changed to control the α-Al 2 O 3 The particle size of the particles. The amount of HCl in the raw material gas when forming the first and second regions is greater than that of the conventional method for forming α-Al 2 O 3 The amount of HCl in the raw material gas used when the first and second regions are formed is set to be greater than or equal to 2.8% by volume and less than 6% by volume. 2 O 3 The average particle size of the particles becomes smaller. This is a new discovery made by the present inventors. The present inventors have completed the cutting tool of the present embodiment based on this new discovery.

[0194] [Note 1]

[0195] The cutting tool disclosed herein has:

[0196] A substrate and a coating disposed on the substrate,

[0197] The coating contains α-Al 2 O 3 layer,

[0198] The α-Al 2 O 3 The layer consists of multiple α-Al 2 O 3 Particle composition,

[0199] In a cross section along the normal line of the surface of the coating,

[0200] From the substrate and the α-Al 2 O 3 The reference line LS1 is based on the interface of the layer to the α-Al 2 O 3 The α-Al on the line L1 at a distance of 0.2 μm from the layer side 2 O 3 The average particle size a of the particles is 0.10 μm or more and 0.30 μm or less.

[0201] From the base line LS1 to the α-Al 2 O 3 The α-Al on the line L2 at a distance of 1.1 μm from the layer side 2 O 3The average particle size b of the particles is 0.30 μm or more and 0.50 μm or less.

[0202] From the α-Al 2 O 3 The surface P2 of the layer, or the α-Al 2 O 3 The interface P3 on the surface side of the coating layer is oriented toward the α-Al 2 O 3 α-Al on line L3 at a distance of 0.6 μm from the layer side 2 O 3 The average particle size c of the particles is 0.50 μm or more and 1.50 μm or less.

[0203] The ratio b / a of a to b is 1.5 or more and 5.0 or less.

[0204] Example

[0205] This embodiment will be described in more detail with reference to examples, but this embodiment is not limited to these examples.

[0206] [Sample 1 to Sample 27, Sample 1-1 to Sample 1-9]

[0207] The raw material powders composed of the blending composition described in Table 1 were uniformly mixed, pressed into a predetermined shape, and then sintered at 1300 to 1500° C. for 1 to 2 hours to obtain a base material made of cemented carbide (shape: model CNMG120408N-UX ("Sumitomo Electric Hardmetal Corp.")). The "remainder" in Table 1 indicates the remainder of the blending composition (mass %) occupied by WC.

[0208] [Table 1]

[0209]

[0210] <Film formation>

[0211] A coating is formed on the surface of the substrate obtained above to produce a cutting tool. Specifically, the substrate is placed in a chemical vapor deposition device, and a coating is formed on the substrate using a chemical vapor deposition method. The composition of the coating of each sample is shown in Table 2.

[0212] [Table 2]

[0213]

[0214] A TiN layer (lower layer), a TiCN layer (middle layer), a TiCNO layer (middle layer), and an α-Al 2 O 3Layer, TiN layer (surface layer). The thickness of the TiN layer (underlying layer) is 0.4 μm, the thickness of the TiCN layer (intermediate layer) is 6.5 μm, the thickness of the TiCNO layer (intermediate layer) is 0.7 μm, and the thickness of the TiN (surface layer) is 0.7 μm. "None" in Table 1 means that the layer is not formed in the sample.

[0215] Table 3 shows the film formation conditions of the TiN layer (underlying layer), the TiCN layer (middle layer), the TiCNO layer (middle layer) and the TiN layer (surface layer).

[0216] [Table 3]

[0217]

[0218] α-Al of each sample 2 O 3 The film forming conditions, raw material gas composition and α-Al 2 O 3 The average thickness of the layer is shown in Table 4. The "remainder" in Table 4 indicates H 2 The gas occupies the remainder of the raw material gas composition (volume %). 2 O 3 The layer formation conditions were as follows: temperature 1000° C., pressure 70 hPa, raw material gas introduction rate (total gas flow rate) 60 L / min, and the gas pipe for spraying the raw material gas was rotated at 2 rpm while the substrate was fixed.

[0219] [Table 4]

[0220]

[0221] For example, the film forming conditions of sample 1 are as follows. 2 O 3 The film formation of the layer starts until the α-Al 2 O 3 The layer thickness was 0.5 μm using a feed gas with the following composition: 2.2 vol% AlCl 3 , 8.3 vol% HCl, 3.0 vol% CO 2 , 0.6 vol% H 2 S and the remainder by H 2 Thus, the first region is formed.

[0222] Next, from α-Al 2 O 3 The thickness of the layer exceeds 0.5 μm until the α-Al 2 O 3The thickness (7 μm) was obtained by subtracting 1 μm from the average thickness (8 μm) of the layer, setting the amount of HCl in the raw material gas to 6.7 vol %, and changing the residual H 2 The amount of , and other than that, the same raw material gas as that used to form the first region was used. Thus, the second region was formed.

[0223] Next, in α-Al 2 O 3 The amount of HCl in the raw gas was set to 3.5 vol% at 1 μm on the surface side of the layer, and the residual H 2 The amount of , except for this, the same raw material gas as that used in the film formation of the second region was used. Thus, the third region was formed.

[0224] <α-Al 2 O 3 Evaluation of the floor>

[0225] For each sample, α-Al 2 O 3 The average particle size a of the first region, the average particle size b of the second region, the average particle size c of the third region, TC (0 0 12) and TC (1 1 0) were measured. The measurement methods are the same as those described in Embodiment 1, so the description thereof will not be repeated. The results are shown in the columns of "Particle size a", "Particle size b", "Particle size c", "TC (0 0 12)" and "TC (1 10)" in Table 5.

[0226] Furthermore, the value of b / a was calculated based on the average particle diameter a and the average particle diameter b. The results are shown in the "b / a" column of Table 5.

[0227] [Table 5]

[0228]

[0229] <Cutting Evaluation 1>

[0230] Using the cutting tool obtained above, a cutting test was carried out under the following cutting condition 1. Using 20 different cutting edges, each cutting edge was cut for 20 seconds to confirm whether there was any breakage. Here, "breakage" refers to a notch of 500 μm or more. Among the 20 cutting edges, the proportion of the cutting edges that were broken was calculated to obtain the breakage rate (%). That is, breakage rate (%) = (number of broken cutting edges / 20) × 100. When the breakage rate is less than 30%, it is judged that the cutting tool has excellent defect resistance and a long tool life. The results are shown in the "Cutting Evaluation 1 Breakage Rate (%)" column of Table 5.

[0231] (Cutting condition 1)

[0232] Cutting material: SCM440 (round bar with grooves)

[0233] Processing: Intermittent turning of the outer diameter of a round bar with grooves

[0234] Cutting speed: 120m / min

[0235] Feed rate: 0.2mm / revolution

[0236] Cutting amount: 2.0mm

[0237] Cutting fluid: None

[0238] The above cutting conditions correspond to efficient machining of high-hardness alloy steel.

[0239] <Cutting Evaluation 2>

[0240] Using the cutting tool obtained above, a cutting test was carried out under the following cutting condition 2. The average wear amount Vb (mm) of the flank side of the cutting tool after cutting for 15 minutes was measured. Here, the "average wear amount" refers to the length obtained by averaging the distance from the ridge to the end of the flank worn. When the average wear amount Vb is 0.25 mm or less, it is judged that the cutting tool has excellent wear resistance and a long tool life. The results are shown in the "Cutting Evaluation 2 Vb (mm)" column of Table 5.

[0241] (Cutting condition 2)

[0242] Cutting material: SCr420H

[0243] Processing: Round bar outer diameter turning

[0244] Cutting speed: 280m / min

[0245] Feed rate: 0.2mm / revolution

[0246] Cutting amount: 2.0mm

[0247] Cutting fluid: water-soluble cutting oil

[0248] The above cutting conditions correspond to efficient machining of alloy steel.

[0249] <Investigation>

[0250] The cutting tools of Samples 1 to 3, 5, 7, 9, 12, 13, 15, 17, and 19 to 27 correspond to Examples. It was confirmed that these samples have excellent chipping resistance and wear resistance and have long tool life.

[0251] α-Al of Sample 1 and Sample 2 2 O 3The thickness of the layer is the same. The average particle size a, average particle size b and average particle size c of sample 1 are the same as the average particle size a, average particle size b and average particle size c of sample 2. In sample 1, TC(0 0 12) is greater than TC(1 10). In sample 2, TC(1 1 0) is greater than TC(0 0 12). It was confirmed that the wear resistance of sample 1 is better than that of sample 2. On the other hand, it was confirmed that the defect resistance of sample 2 is better than that of sample 1. As described above, it can be confirmed that: in α-Al 2 O 3 When the thickness of the layer, the average particle size a of the first region, the average particle size b of the second region, and the average particle size c of the third region are the same, the larger the TC (0 0 12), the higher the wear resistance, and the larger the TC (1 1 0), the higher the defect resistance. This tendency can also be confirmed from the comparison between Sample 10 and Sample 11.

[0252] Samples 4, 6, 8, 10, 11, 14, 16, 18, and 1-1 to 1-9 correspond to comparative examples. Samples 4, 6, 8, 10, 11, 14, 18, and 1-1 to 1-9 have insufficient defect resistance and short tool life. Sample 16 has insufficient wear resistance and short tool life.

[0253] As mentioned above, although the embodiment and the example of the present disclosure have been described, it is initially intended that the configurations of the above-described embodiments and the examples may be appropriately combined or various modifications may be made.

[0254] The embodiments and examples disclosed herein are illustrative in all aspects and are not restrictive. The scope of the present invention is indicated by the claims rather than the embodiments and examples described above, and is intended to include all changes within the meaning and scope equivalent to the claims.

[0255] Explanation of symbols

[0256] 1, 21, 31, 41 cutting tool, 10 substrate, 11 α-Al2O3 layer, 12 lower layer, 13 surface layer, 14 intermediate layer, 15, 25, 35, 45 coating, A1 first region, A2 second region, A3 third region, A4 fourth region, P1, P3 interface, P2 surface, S1, S2, S3 virtual surface, B1 peak of P1, T1 valley of P1, LS1 baseline, L1, L2 line

Claims

1. A cutting tool comprising: A substrate, and a coating disposed on the substrate, The coating comprises an α-Al2O3 layer, The α-Al2O3 layer is composed of a plurality of α-Al2O3 particles. The α-Al2O3 layer includes a first region, a second region and a third region, The first region is a region sandwiched between the interface P1 on the substrate side of the α-Al 2 O 3 layer and a virtual plane S1 at a distance of 0.5 μm from the interface P1 to the surface side of the coating. The second region is a region sandwiched between the virtual surface S1 and a virtual surface S2 that is 1.0 μm away from the virtual surface S1 toward the surface side of the coating. The third region is a region sandwiched between the surface P2 of the α-Al2O3 layer or the interface P3 on the surface side of the film of the α-Al2O3 layer and a virtual plane S3 at a distance of 1.0 μm from the surface P2 or the interface P3 toward the substrate side. The average particle size a of the α-Al2O3 particles in the first region is not less than 0.10 μm and not more than 0.30 μm, The average particle size b of the α-Al2O3 particles in the second region is not less than 0.30 μm and not more than 0.50 μm, The average particle size c of the α-Al2O3 particles in the third region is greater than 0.50 μm and is less than 1.50 μm. The ratio b / a of a to b is 1.5 or more and 5.0 or less.

2. The cutting tool according to claim 1, wherein: The average particle size c is greater than 0.50 μm and less than or equal to 1.20 μm.

3. The cutting tool according to claim 1 or claim 2, wherein: The b / a is 1.5 or more and 2.5 or less.

4. The cutting tool according to claim 1 or claim 2, wherein: The average thickness of the α-Al 2 O 3 layer is greater than or equal to 3 μm and less than or equal to 15 μm.

5. The cutting tool according to claim 1 or claim 2, wherein: The α-Al2O3 layer has a texture coefficient TC(h kl) of TC(0 0 12) of 3 or more.

6. The cutting tool according to claim 1 or claim 2, wherein: The average particle size a is not less than 0.12 μm and not more than 0.28 μm.

7. The cutting tool according to claim 1 or claim 2, wherein: The average particle size b is not less than 0.32 μm and not more than 0.48 μm.

8. The cutting tool according to claim 1 or claim 2, wherein: The ratio b / a is 1.7 to 2.

3.

9. The cutting tool according to claim 1 or claim 2, wherein: The ratio b / a is 1.9 to 2.

1.

10. The cutting tool according to claim 1 or claim 2, wherein: The TC(0 0 12) in the texture coefficient TC(h kl) of the α-Al2O3 layer is 4 or more and 8 or less.

11. The cutting tool according to claim 1 or claim 2, wherein: The TC(1 1 0) in the texture coefficient TC(hkl) of the α-Al2O3 layer is greater than or equal to 2 and less than or equal to 8.

12. The cutting tool according to claim 1 or claim 2, wherein: The coating includes an underlayer disposed between the substrate and the α-Al 2 O 3 layer.

13. The cutting tool according to claim 1 or claim 2, wherein: The coating includes a surface layer disposed on the outermost surface side of the coating.

14. The cutting tool according to claim 12, wherein: The coating includes an intermediate layer disposed between the lower base layer and the α-Al 2 O 3 layer.

15. A cutting tool comprising: A substrate and a coating disposed on the substrate, The coating comprises an α-Al2O3 layer, The α-Al2O3 layer is composed of a plurality of α-Al2O3 particles. In a cross section along a normal line to the surface of the coating, The average particle size a of the α-Al2O3 particles on a line L1 at a distance of 0.2 μm from a reference line LS1 based on the interface between the substrate and the α-Al2O3 layer to the α-Al2O3 layer side is 0.10 μm or more and 0.30 μm or less, The average particle size b of the α-Al 2 O 3 particles on a line L2 at a distance of 1.1 μm from the reference line LS1 toward the α-Al 2 O 3 layer is 0.30 μm or more and 0.50 μm or less. The average particle size c of the α-Al2O3 particles on the line L3 at a distance of 0.6 μm from the surface P2 of the α-Al2O3 layer or the interface P3 on the surface side of the coating of the α-Al2O3 layer to the α-Al2O3 layer side is greater than 0.50 μm and is less than 1.50 μm, The ratio b / a of a to b is 1.5 or more and 5.0 or less.

Images