Coated tool and cutting tool

Abstract

This coated tool comprises a base body and a coating layer positioned above the base body. The coating layer has a first layer, a second layer positioned between the first layer and the base body and in contact with the first layer and multiple crystal projections positioned in the interface between the first layer and the second layer. The multiple crystal projections respectively project towards the first layer and the second layer.

Description

Coated and cutting tools

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

[0002] As a tool used in cutting processes such as turning or milling, a coated tool having a substrate made of cemented carbide, cermet, ceramic, or the like coated with a coating layer is known. Coating with a coating layer can improve the wear resistance and other properties of the tool.

[0003] International Publication No. 2016 / 017790

[0004] A coated tool according to one embodiment of the present disclosure includes a substrate and a coating layer disposed on the substrate. The coating layer has a first layer, a second layer disposed between the first layer and the substrate and in contact with the first layer, and a plurality of protruding crystals disposed at the interface between the first layer and the second layer. The protruding crystals protrude toward the first layer and the second layer, respectively.

[0005] FIG. 1 is a perspective view showing an example of a coated tool according to an embodiment. FIG. 2 is a side cross-sectional view showing an example of a coated tool according to an embodiment. FIG. 3 is a schematic enlarged view of a corner portion of a tip body according to a reference example. FIG. 4 is a cross-sectional view showing an example of a coating layer according to an embodiment. FIG. 5 is a cross-sectional view showing an example of details of the coating layer according to an embodiment. FIG. 6 is the same cross-sectional view as FIG. 5. FIG. 7 is a front view showing an example of a cutting tool according to an embodiment. FIG. 8 is an image showing a cross-section of a coating layer at the cutting edge of a coated tool according to an example and the results of elemental analysis of the coating layer. FIG. 9 is an image showing an inverse pole figure orientation map of the coating layer at the cutting edge of a coated tool according to an example. FIG. 10 is a graph showing the correlation between cutting time and abrasive wear amount. FIG. 11 is an image showing the cutting edge condition of a coated tool according to an example after a cutting test. FIG. 12 is an image showing the cutting edge condition of a coated tool according to a comparative example after a cutting test.

[0006] Hereinafter, modes for carrying out a coated tool and a cutting tool according to the present disclosure (hereinafter referred to as "embodiments") will be described in detail with reference to the drawings. The coated tool and the cutting tool according to the present disclosure are not limited to these embodiments. The respective embodiments can be appropriately combined within the scope of not causing contradictions in the content. In the following embodiments, the same components are designated by the same reference numerals, and redundant explanations will be omitted.

[0007] As a tool used in cutting processes such as turning or milling, a coated tool having a substrate made of cemented carbide, cermet, ceramics, etc. coated with a coating layer is known. Coating with a coating layer can improve the wear resistance and other properties of the tool.

[0008] The above-mentioned prior art still has room for improvement in terms of improving wear resistance.

[0009] Therefore, there is a need for a technology that can overcome the above-mentioned problems and improve wear resistance.

[0010] <Coated tool> Fig. 1 is a perspective view showing an example of a coated tool according to an embodiment. Fig. 2 is a side cross-sectional view showing an example of a coated tool according to an embodiment. As shown in Fig. 1, the coated tool 1 according to the embodiment has a tip body 2.

[0011] (Chip Body 2) The chip body 2 has, for example, a hexahedral shape in which the upper and lower surfaces (surfaces intersecting with the Z axis shown in FIG. 1) are parallelogram-shaped.

[0012] One corner portion 201 of the insert body 2 functions as a cutting edge portion. The cutting edge portion has a first surface (for example, an upper surface) and a second surface (for example, a side surface) that is connected to the first surface. In the embodiment, the first surface functions as a "rake surface" that scoops up chips generated by cutting, and the second surface functions as a "flank surface." A cutting edge is located on at least a portion of the ridge where the first surface and the second surface intersect, and the coated tool 1 cuts the workpiece by applying this cutting edge to the workpiece.

[0013] A through-hole 5 that passes through the tip body 2 from top to bottom is located in the center of the tip body 2. A screw 75 is inserted into the through-hole 5 to attach the coated tool 1 to a holder 70 (described later) (see FIG. 7).

[0014] 1 is merely an example and does not limit the shape of the coated tool according to the present disclosure. The coated tool according to the present disclosure may, for example, have a rod-shaped body having a rotation axis and extending from a first end to a second end, a cutting edge located at the first end of the body, and a groove extending spirally from the cutting edge toward the second end of the body.

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

[0016] (Substrate 10) The substrate 10 is formed, for example, from a cemented carbide. The cemented carbide contains a hard phase containing at least W (tungsten), specifically WC (tungsten carbide). The cemented carbide may contain a binder phase containing at least one iron group element such as Ni (nickel) or Co (cobalt). As an example, the substrate 10 is made of a WC-based cemented carbide having hard particles made of WC as the hard phase component and Co as the main component of the binder phase. When the substrate 10 is formed from a cemented carbide, the substrate 10 has better heat resistance properties.

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

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

[0019] The substrate 10 may be made of ceramics. The ceramics may be, for example, Al. ２ O ３ (aluminum oxide), for example, κ-Al２ O ３ and / or α-Al ２ O ３ The ceramic may contain other elements in addition to aluminum oxide. For example, the ceramic may contain, in addition to aluminum oxide, at least one of magnesium (Mg), calcium (Ca), strontium (Sr), silicon (Si), and an element from Group 3 of the periodic table.

[0020] (Coating layer 20) The coating layer 20 coats the substrate 10 for the purpose of improving the abrasion resistance, heat resistance, etc. of the substrate 10. In the example of FIG. 2, the coating layer 20 coats the entire substrate 10. The arrangement of the coating layer 20 on the substrate 10 is not particularly limited as long as the coating layer 20 is located at least on the surface of the substrate 10. When the coating layer 20 is located on the first surface (here, the top surface) of the substrate 10, the abrasion resistance and heat resistance of the first surface are high. When the coating layer 20 is located on the second surface (here, the side surface) of the substrate 10, the abrasion resistance and heat resistance of the second surface are high.

[0021] (Damage to the Chip Body) Damage to the chip body will now be described with reference to Fig. 3. Fig. 3 is a schematic enlarged view of a corner portion 201X of a chip body 2X according to a reference example.

[0022] 3, the insert body 2X may undergo wear such as primary boundary wear D1, secondary boundary wear D2, abrasive wear D3, and crater wear D4. The primary boundary wear D1, secondary boundary wear D2, and abrasive wear D3 occur on the flank face, and the crater wear D4 occurs on the rake face.

[0023] Abrasive wear D3 is a wear phenomenon in which the surface of the tip body 2X is scraped away by foreign matter interposed between the tip body 2X and the workpiece. Abrasive wear D3 may cause an increase in cutting resistance and cutting heat.

[0024] Primary boundary wear D1 and secondary boundary wear D2 are wear that occurs at both ends of abrasive wear D3, i.e., at the cutting boundary. The primary boundary is the boundary that contacts the cutting surface of the workpiece, and the secondary boundary is the boundary that contacts the finished surface of the workpiece. Primary boundary wear D1 may cause burrs to form on the workpiece. Secondary boundary wear D2 may deteriorate the finished surface of the workpiece or change the dimensions of the workpiece.

[0025] Crater wear D4 occurs when the insert body 2X is heated to a high temperature, oxidizing the surface and generating relatively soft oxides. Crater wear D4 may deteriorate chip disposal.

[0026] The coated tool 1 according to the embodiment can suitably reduce such damage by devising the configuration of the coating layer 20 that coats the tip body 2 .

[0027] (Configuration of Covering Layer 20) Here, an example of the configuration of the covering layer 20 according to the embodiment will be described with reference to Fig. 4. Fig. 4 is a cross-sectional view showing an example of the covering layer 20 according to the embodiment.

[0028] 4 , the coating layer 20 has a first layer 21, a second layer 22, and a third layer 23. The first layer 21 is located on the outer side of the coating layer 20 compared to the second layer 22 and the third layer 23. The second layer 22 is located between the first layer 21 and the substrate 10. The third layer 23 is located between the second layer 22 and the substrate 10. That is, the second layer 22 is located between the first layer 21 and the third layer 23.

[0029] The first layer 21 may be located as the outermost layer of the coating layer 20. In such a case, the first layer 21 is generally referred to as a wear-resistant layer because it contacts the workpiece. Therefore, hereinafter, the first layer 21 will be referred to as the wear-resistant layer 21 as appropriate. The second layer 22 is located between the first layer 21 and the third layer 23 as described above, and therefore may also be referred to as the intermediate layer 22. The second layer 22, which is located inside the coating layer 20 with respect to the first layer 21, may contact the first layer 21, as in the example shown in FIG. 4 .

[0030] The third layer 23 may be located at the innermost portion of the coating layer 20. In such a case, the third layer 23 is positioned as a region that contacts the substrate 10 and enhances the adhesion of the coating layer 20 to the substrate 10. Therefore, the third layer 23 is generally referred to as an adhesion layer. Hereinafter, the third layer 23 will be appropriately referred to as the adhesion layer 23. The adhesion layer 23 may be in contact with the intermediate layer 22, as in the example shown in FIG. 4. Another layer may be located between the intermediate layer 22 and the adhesion layer 23, and the adhesion layer 23 may be separated from the intermediate layer 22. In the example shown in FIG. 4, the adhesion layer 23, the intermediate layer 22, and the wear-resistant layer 21 are stacked in this order from the surface side of the substrate 10: adhesion layer 23, intermediate layer 22, and wear-resistant layer 21.

[0031] The wear-resistant layer 21 contains a metal component including Ti and Al, and at least one element selected from the group consisting of carbon, nitrogen, and oxygen. However, the composition of the wear-resistant layer 21 is different from the composition of the intermediate layer 22. For example, the wear-resistant layer 21 contains Ti as a metal component. ｇ Al ｈ Cr ｉ M ｊ The composition of the wear-resistant layer 21 is defined as a first composition. M is at least one metal selected from Groups 4a, 5a, and 6a of the periodic table (excluding Cr) and Si. g, h, i, and j are all atomic ratios, 15≦g≦40, 50≦h≦70, and 5≦i≦20, and g+h+i+j=100. As an example, the wear-resistant layer 21 may be TiAlCrWNbSiN. The wear-resistant layer 21 does not necessarily need to contain M. In this case, the wear-resistant layer 21 may be, for example, TiAlCrN. The wear-resistant layer 21 is a layer that comes into contact with the workpiece when cutting the workpiece with the coated tool 1, and can reduce the occurrence of primary boundary wear D1, secondary boundary wear D2, and abrasive wear D3 in the tip body 2.

[0032] The intermediate layer 22 contains a metal component including Ti and Al, and at least one element selected from the group consisting of carbon, nitrogen, and oxygen. For example, the intermediate layer 22 contains Ti as the metal component. ｄ Al ｅ M ｆThe intermediate layer 22 has a second composition. M is at least one metal selected from Groups 4a, 5a, and 6a of the periodic table (excluding Cr) and Si. d, e, and f are atomic ratios, where 0≦d≦55, 40≦e≦80, and d+e+f=100. As an example, the intermediate layer 22 may be TiAlWNbSiN. The intermediate layer 22 does not necessarily contain M. In this case, the intermediate layer 22 may be, for example, TiAlN. The intermediate layer 22 has high oxidation resistance, which can reduce the occurrence of crater wear D4 in the tip body 2.

[0033] The adhesion layer 23 is an alloy layer containing Ti and Al. For example, the adhesion layer 23 is ａ Al ｂ M ｃ The adhesion layer 23 is an alloy layer containing M. M is at least one metal selected from Groups 4a, 5a, and 6a of the periodic table, and Si. The composition of the adhesion layer 23 is referred to as a third composition. a, b, and c are all atomic ratios, 40≦a≦80, and 0≦b≦55, and a+b+c=100. As an example, the adhesion layer 23 may be TiAlWNbSi. The adhesion layer 23 does not necessarily need to contain M. In this case, the adhesion layer 23 may be, for example, TiAl. The adhesion layer 23 improves the adhesion of the coating layer 20 to the substrate 10. This makes it easier to prevent the coating layer 20 from peeling off from the substrate 10.

[0034] The proportion of metal components in the adhesive layer 23, the intermediate layer 22 and the wear-resistant layer 21 can be determined, for example, by analysis using an EDS (energy dispersive X-ray spectrometer) attached to an STEM (scanning transmission electron microscope).

[0035] The thickness of the coating layer 20 may be 2.5 μm or more and 10 μm or less. When the thickness of the coating layer 20 is 2.5 μm or more, wear resistance (particularly resistance to abrasive wear D3) can be more easily ensured. When the thickness of the coating layer 20 is 10 μm or less, chipping of the coating layer 20 can be more easily reduced. Therefore, when the thickness of the coating layer 20 is 2.5 μm or more and 10 μm or less, the wear resistance and chipping resistance of the coating layer 20 can be improved.

[0036] The thickness of the adhesion layer 23 may be 2 nm or more and 8 nm or less. When the thickness of the adhesion layer 23 is 2 nm or more, the adhesion of the coating layer 20 to the substrate 10 can be more easily improved. In addition, the occurrence of primary boundary wear D1 and secondary boundary wear D2 in the chip body 2 can be more easily reduced. On the other hand, when the thickness of the adhesion layer 23 is 8 nm or less, the plastic deformation of the relatively soft adhesion layer 23 can be reduced, thereby more easily reducing the destruction of the coating layer 20. Therefore, when the thickness of the adhesion layer 23 is 2 nm or more and 8 nm or less, the occurrence of primary boundary wear D1 and secondary boundary wear D2 in the chip body 2 and the destruction of the coating layer 20 can be reduced.

[0037] The thickness of the intermediate layer 22 may be smaller than the thickness of the wear-resistant layer 21. For example, the thickness of the intermediate layer 22 may be 0.5 μm or more and 3 μm or less. When the thickness of the intermediate layer 22 is 0.5 μm or more, the occurrence of crater wear D4 in the tip body 2 can be more easily reduced. On the other hand, when the thickness of the intermediate layer 22 is 3 μm or less, the effect of the wear-resistant layer 21 in reducing the occurrence of primary boundary wear D1, secondary boundary wear D2, and abrasive wear D3 in the tip body 2 can be more easily ensured. Therefore, when the thickness of the intermediate layer 22 is 0.5 μm or more and 3 μm or less, damage to the tip body 2 can be more easily reduced.

[0038] The thickness of the wear-resistant layer 21 may be 1.5 μm or more and 7 μm or less. When the thickness of the wear-resistant layer 21 is 1.5 μm or more, the occurrence of primary boundary wear D1, secondary boundary wear D2, and abrasive wear D3 in the tip body 2 can be more easily reduced. On the other hand, when the thickness of the wear-resistant layer 21 is 7 μm or less, the effect of the intermediate layer 22 in reducing the occurrence of crater wear D4 in the tip body 2 can be more easily ensured. Therefore, when the thickness of the wear-resistant layer 21 is 1.5 μm or more and 7 μm or less, damage to the tip body 2 can be more easily reduced.

[0039] Here, an example has been shown in which the coating layer 20 is composed of the adhesion layer 23, the intermediate layer 22, and the wear-resistant layer 21, but the coating layer 20 does not necessarily need to include the adhesion layer 23. For example, when the adhesion of the coating layer 20 to the substrate 10 is high and / or when the coated tool 1 is intended for a workpiece material that is less susceptible to primary boundary wear D1 and secondary boundary wear D2, the coated tool 1 may have the coating layer 20 composed of the intermediate layer 22 located on the surface of the substrate 10 and the wear-resistant layer 21 located on the surface of the intermediate layer 22.

[0040] Here, an example of the details of the coating layer 20 according to the embodiment will be described with reference to Fig. 5. Fig. 5 is a cross-sectional view showing an example of the details of the coating layer 20 according to the embodiment.

[0041] As shown in Figure 5, the coating layer 20 of this embodiment has a plurality of protruding crystals 30 located at the interface between the intermediate layer 22 and the wear-resistant layer 21 in a cross section of the coating layer 20 including the intermediate layer 22 and the wear-resistant layer 21.

[0042] For example, a scanning transmission electron microscope (STEM) or the like is used to take a photograph of a cross section of the coating layer 20 including the intermediate layer 22 and the wear-resistant layer 21 in the normal direction to the surface of the substrate 10. In the photograph of the cross section of the coating layer 20, a plurality of protruding crystals 30 located at the interface between the intermediate layer 22 and the wear-resistant layer 21 can be confirmed.

[0043] In an analysis using TEM electron diffraction mapping, an inverse pole figure orientation map of the coating layer 20 shows that the crystal orientation in the region corresponding to the protruding crystals 30 is different from the crystal orientation in the region corresponding to the portion other than the protruding crystals 30. That is, the inverse pole figure orientation map of the coating layer 20 also allows confirmation of the multiple protruding crystals 30 at the interface between the intermediate layer 22 and the wear-resistant layer 21. This suggests that the orientation of the crystal grains that make up the multiple protruding crystals 30 is different from the orientation of the crystal grains that make up the intermediate layer 22 and the orientation of the crystal grains that make up the wear-resistant layer 21.

[0044] In elemental analysis using an EDS (energy dispersive X-ray spectroscope) attached to an STEM, the distribution of elements constituting the intermediate layer 22 and the wear-resistant layer 21 does not indicate the presence of multiple protruding crystals 30 at the interface between the intermediate layer 22 and the wear-resistant layer 21. That is, the multiple protruding crystals 30 can also be evaluated as being part of the wear-resistant layer 21 and the intermediate layer 22. However, based on the TEM electron diffraction mapping method, the multiple protruding crystals 30 will be described in detail below as elements separate from the wear-resistant layer 21 and the intermediate layer 22. Because the composition of the elements constituting the intermediate layer 22 is different from the composition of the elements constituting the wear-resistant layer 21, the presence of the interface between the intermediate layer 22 and the wear-resistant layer 21 can be confirmed in the above elemental analysis.

[0045] Therefore, when forming the wear-resistant layer 21 on the intermediate layer 22, it is thought that the orientation of the crystal grains that make up part of the wear-resistant layer 21 is influenced by the orientation of the crystal grains that make up part of the intermediate layer 22, resulting in the formation of multiple protruding crystals 30 at the interface between the intermediate layer 22 and the wear-resistant layer 21.

[0046] In this way, when the coating layer 20 has a plurality of protruding crystals 30 at the interface between the intermediate layer 22 and the wear-resistant layer 21, and the plurality of protruding crystals 30 protrude toward the wear-resistant layer 21 and the intermediate layer 22, respectively, the anchor effect of the plurality of protruding crystals 30 can improve the adhesion between the intermediate layer 22 and the wear-resistant layer 21. This can improve the wear resistance of the coating layer 20. Therefore, the wear resistance of the coated tool 1 can be improved. As a result, the tool life of the coated tool 1 can be extended.

[0047] Here, when at least one of the plurality of protruding crystals 30 has a portion that protrudes at an acute angle toward the abrasion-resistant layer 21 and the intermediate layer 22, respectively, the anchoring effect of this protruding crystal 30 is improved. When more than half of the plurality of protruding crystals 30 have a portion that protrudes at the above-mentioned acute angle, the anchoring effect of the plurality of protruding crystals 30 is further improved.

[0048] In particular, when at least one of the multiple protruding crystals 30 has a configuration in which the width L2 in the direction normal to the surface is larger than the width L1 in the direction along the surface of the base 10 (a configuration in which the crystals are elongated in the vertical direction in the cross section shown in Figure 6), the anchor effect described above can be enhanced.

[0049] A plurality of protruding crystals 30 are located at the interface between the intermediate layer 22 and the wear-resistant layer 21. Therefore, at least one of the plurality of protruding crystals 30 can be considered to have a first region 30a surrounded by the wear-resistant layer 21 and a second region 30b surrounded by the intermediate layer 22. As described above, in elemental analysis using EDS, the distribution of elements constituting the intermediate layer 22 and the wear-resistant layer 21 does not indicate the presence of a plurality of protruding crystals 30 at the interface between the intermediate layer 22 and the wear-resistant layer 21. In this case, it can also be said that in at least one of the protruding crystals 30, the first region 30a has a first composition and the second region 30b has a second composition.

[0050] When at least one of the multiple protruding crystals 30 has the above configuration, the adhesion between the intermediate layer 22 and the wear-resistant layer 21 is further improved. This is for the following reasons: The affinity between the wear-resistant layer 21 and the first regions 30a in the protruding crystals 30 is high, resulting in a high adhesion between these regions. The affinity between the intermediate layer 22 and the second regions 30b in the protruding crystals 30 is high, resulting in a high adhesion between these regions. As shown in the inverse pole figure orientation map of Figure 9, the crystal orientations of the first regions 30a and the second regions 30b in the protruding crystals 30 are aligned. Therefore, the bonding strength between the first regions 30a and the second regions 30b is high.

[0051] When the plurality of protruding crystals 30 have first regions 30a and second regions 30b, at least one of the plurality of protruding crystals 30 may have a configuration in which the width (height in the vertical direction in the cross section shown in FIG. 6 ) in the first region 30a and the second region 30b in the direction normal to the surface of the base 10 is not extremely biased. Specifically, when the width in the direction normal to the surface of the base 10 in the first region 30a is h1 and the width in the direction normal to the surface of the base 10 in the second region 30b is h2, the relationship h1 / h2 may be 0.2 < h1 < 5. In this case, the anchoring effect of the protruding crystals 30 to both the wear-resistant layer 21 and the intermediate layer 22 is enhanced.

[0052] Next, the shape of the protruding crystals 30 according to the embodiment will be described with reference to Fig. 5. Fig. 5 is a cross-sectional view showing an example of the shape of the protruding crystals 30 according to the embodiment.

[0053] As shown in Figure 5, each protrusion-like crystal 30 has a polygonal shape in a cross section of the coating layer 20 taken in the normal direction to the surface of the base 10 (the vertical direction in Figure 5). For example, the shape of each protrusion-like crystal 30 can be identified visually in a cross section of the coating layer 20 including the intermediate layer 22 and the abrasion-resistant layer 21 taken in the normal direction to the surface of the base 10. Alternatively, the shape of each protrusion-like crystal 30 may be identified visually based on the distribution of crystal grain orientation in an inverse pole figure orientation map of the coating layer 20.

[0054] 5, the plurality of protruding crystals 30 may have a substantially polygonal shape in a cross section of the coating layer 20 taken in the normal direction to the surface of the base 10. Here, the substantially polygonal shape includes a shape that can be considered to be substantially a polygon and a shape that can be approximated to a polygon.

[0055] If at least one of the corners of the protruding crystal 30, which has an approximately polygonal shape, located in the wear-resistant layer 21 and at least one of the corners located in the intermediate layer 22 are acute angles, the anchoring effect of the protruding crystal 30 is improved.

[0056] FIG. 5 shows a substantially triangular protrusion crystal 30 as an example of a substantially polygonal protrusion crystal 30. This substantially triangular protrusion crystal 30 has, for example, vertices A, B, and C. Vertex A is the vertex farthest from the intermediate layer 22. In triangle ABC, a, b, and c are the lengths of sides BC, CA, and AB, respectively. H is the foot of the perpendicular line drawn from vertex A to side BC. h is the length of perpendicular line AH. For example, the values ​​of a, b, c, and h are measured from the shape of triangle ABC. The area S of triangle ABC can be calculated from the obtained values ​​of a, b, and c. For example, using Heron's formula (S={s(s-a)(s-b)(s-c)} １／２ However, the area S can be calculated using s = (a + b + c) / 2. Instead of measuring the length h of the perpendicular line AH, the length h of the perpendicular line AH may be calculated from the obtained area S according to the formula h = 2S / a.

[0057] At least one of the plurality of protruding crystals 30 may have a height of 500 nm or more. When the protruding crystals 30 have a substantially triangular shape in the cross section of the coating layer 20 in the normal direction to the surface of the base 10, the height of the protruding crystals 30 is the length h of the perpendicular line AH as described above. The height of the protruding crystals 30 may be the average value of the heights of the plurality of protruding crystals 30.

[0058] When at least one of the plurality of protruding crystals 30 has a height of 500 nm or more, the anchoring effect of the plurality of protruding crystals 30 can be improved. This further improves the adhesive force acting between the intermediate layer 22 and the wear-resistant layer 21. This further improves the wear resistance of the coating layer 20. This further improves the wear resistance of the coated tool 1. As a result, the tool life of the coated tool 1 can be further extended.

[0059] At least one of the plurality of protruding crystals 30 may have an inclination angle of 15 degrees or more and 45 degrees or less with respect to the normal direction to the surface of the base 10. When the protruding crystals 30 have a substantially triangular shape in the cross section of the coating layer 20 in the normal direction to the surface of the base 10, the inclination angle of the protruding crystals 30 with respect to the normal direction to the surface of the base 10 is the angle of the perpendicular line AH as described above with respect to the normal line to the surface of the base 10. The average value of the inclination angles of the plurality of protruding crystals 30 with respect to the normal direction to the surface of the base 10 may be used as the inclination angle of the protruding crystals 30 with respect to the normal direction to the surface of the base 10.

[0060] When at least one of the plurality of protruding crystals 30 has an inclination angle of 15 degrees or more and 45 degrees or less with respect to the normal direction to the surface of the base 10, the anchoring effect of the plurality of protruding crystals 30 can be improved. This can further improve the adhesive force acting between the intermediate layer 22 and the wear-resistant layer 21. This can further improve the wear resistance of the coating layer 20. This can further improve the wear resistance of the coated tool 1. As a result, the tool life of the coated tool 1 can be further extended.

[0061] At least one of the plurality of protruding crystals 30 may have an aspect ratio of 0.1 or more and 1 or less. When the protruding crystals 30 have a substantially triangular shape in the cross section of the coating layer 20 in the normal direction to the surface of the substrate 10, the aspect ratio of the protruding crystals 30 is calculated as follows: As shown in Fig. 5, when the protruding crystals 30 are triangles ABC having vertices A, B, and C, the aspect ratio AR of the protruding crystals 30 is calculated by the formula AR = 2 x R ＩＣ / R ＣＣ where R ＩＣ is the radius of the inscribed circle IC of the triangle ABC. ＣＣ is the radius of the circumscribing circle CC of the triangle ABC. Based on the area S of the triangle ABC and the lengths a, b, and c of the triangle's sides, the radius R of the inscribing circle IC of the triangle ABC is ＩＣ is the formula R ＩＣ = 2 × S / (a ​​+ b + c) The radius R of the circumscribing circle CC of the triangle ABC ＣＣ is the formula R ＣＣ= a × b × c / (4 × S) As the aspect ratio of the protruding crystals 30, the average value of the aspect ratios of the plurality of protruding crystals 30 may be used.

[0062] When at least one of the plurality of protruding crystals 30 has an aspect ratio of 0.1 or more and 1 or less, the anchoring effect of the plurality of protruding crystals 30 can be improved. Therefore, the adhesive force acting between the intermediate layer 22 and the wear-resistant layer 21 can be further improved. Accordingly, the wear resistance of the coating layer 20 can be further improved. Therefore, the wear resistance of the coated tool 1 can be further improved. As a result, the tool life of the coated tool 1 can be further extended.

[0063] As described above, the intermediate layer 22 may have a second composition including a metal component containing Ti and Al and at least one element selected from the group consisting of carbon, nitrogen, and oxygen. The wear-resistant layer 21 may have a first composition including a metal component containing Ti and Al and at least one element selected from the group consisting of carbon, nitrogen, and oxygen. In this case, the first composition and the second composition may be different from each other.

[0064] In this case, it is possible to more easily provide the coating layer 20 having a plurality of protruding crystals 30 at the interface between the intermediate layer 22 and the wear-resistant layer 21. Therefore, it is possible to more easily improve the adhesive force acting between the intermediate layer 22 and the wear-resistant layer 21. Accordingly, it is possible to more easily improve the wear resistance of the coating layer 20. Therefore, it is possible to more easily improve the wear resistance of the coated tool 1. As a result, it is possible to more easily extend the tool life of the coated tool 1.

[0065] At least one of the plurality of protruding crystals 30 may have a substantially quadrangular shape in a cross section of the coating layer 20 taken in the normal direction to the surface of the substrate 10, as shown in Fig. 5, for example. Here, the term "substantially quadrangular shape" includes a shape that can be considered to be substantially a quadrangular shape and a shape that can be approximated to a quadrangular shape.

[0066] As shown in FIG. 5 , the protruding crystal 30 has, for example, vertices D, E, F, and G. Next, for the quadrangle DEFG, a portion of a triangle DGF including the side FG closest to the intermediate layer 22 and the longer side DG of the sides EF and DG connected to side FG is extracted. For the protruding crystal 30 having a substantially quadrangular shape, the height, tilt angle, and aspect ratio of the protruding crystal 30 are calculated for this portion of the triangle DGF, as described above. When the protruding crystal 30 has another polygonal shape, a portion of a triangle including the side closest to the intermediate layer 22 and the longer of the two sides connected to the side closest to the intermediate layer 22 is similarly extracted.

[0067] (Method for manufacturing the coating layer 20) Next, an example of a method for manufacturing the coating layer 20 according to this embodiment will be described. The method for manufacturing the coating layer 20 according to this embodiment is not limited to the following manufacturing method.

[0068] The coating layer 20 may be formed by, for example, a physical vapor deposition (PVD) method. For example, when the coating layer 20 is formed by utilizing the physical vapor deposition method while the base body 10 is held on the inner peripheral surface of the through hole 5, the coating layer 20 can be formed so as to cover the entire surface of the base body 10 except for the inner peripheral surface of the through hole 5.

[0069] Examples of physical vapor deposition methods include ion plating methods such as arc ion plating (AIP) and sputtering. Arc ion plating is a method of evaporating a target metal in a vacuum atmosphere by using arc discharge, and optionally N ２ This is a method for forming a film of a metal or metal nitride by combining with a gas, etc. At this time, the bias voltage applied to the substrate 10, which is the object to be coated, may be −30 V or less.

[0070] As an example, when the coating layer 20 is produced by the arc ion plating method, the coating layer 20 can be produced by the following method.

[0071] First, a description will be given of an example of a method for manufacturing the adhesion layer 23. As an example, a metal target, a composite alloy target, or a sintered target of Ti, Al, and M (where M is at least one metal selected from Groups 4a, 5a, and 6a of the periodic table, and Si) is prepared.

[0072] Next, the target, which is the metal source, is evaporated and ionized by arc discharge or glow discharge, and the ionized metal is vapor-deposited on the surface of the substrate 10. By the above procedure, the adhesion layer 23 can be formed.

[0073] The composition of the adhesion layer 23 can be adjusted by independently controlling the voltage or current value applied to each metal target during arc discharge or glow discharge. The composition of the adhesion layer 23 can also be adjusted by controlling the composition of the metal target, the coating time, or the atmospheric gas pressure. The thickness of the adhesion layer 23 can be adjusted, for example, by controlling the coating time.

[0074] Next, a description will be given of an example of a method for manufacturing the intermediate layer 22. As an example, a metal target, a composite alloy target, or a sintered target of Ti, Al, and M (where M is at least one metal selected from Groups 4a, 5a, and 6a of the periodic table (excluding Cr) and Si) is prepared.

[0075] Next, the target, which is the metal source, is evaporated and ionized by arc discharge or glow discharge. The ionized metal is then evaporated with nitrogen (N ２ ) gas and is deposited on the surface of the substrate 10. The intermediate layer 22 can be formed by the above procedure.

[0076] The composition of the intermediate layer 22 can be adjusted by controlling the composition of the metal target. The grain size of the intermediate layer 22 can be adjusted by controlling the current value during arc discharge or glow discharge or by controlling the atmospheric gas pressure. The thickness of the intermediate layer 22 can be adjusted, for example, by controlling the coating time.

[0077] Next, a description will be given of a method for manufacturing the wear-resistant layer 21. As an example, a metal target, a composite alloy target, or a sintered target of Ti, Al, Cr, and M (where M is at least one metal selected from Groups 4a, 5a, and 6a of the periodic table (excluding Cr), and Si) is prepared.

[0078] Next, the target, which is the metal source, is evaporated and ionized by arc discharge or glow discharge. The ionized metal is then evaporated with nitrogen (N ２ ) gas and is deposited on the surface of the substrate 10. The abrasion-resistant layer 21 can be formed by the above procedure.

[0079] The composition of the wear-resistant layer 21 can be adjusted by controlling the composition of the metal target. The grain size of the wear-resistant layer 21 can be adjusted by controlling the voltage or current value during arc discharge or glow discharge, or by controlling the atmospheric gas pressure. The thickness of the wear-resistant layer 21 can be adjusted, for example, by controlling the coating time.

[0080] <Cutting Tool> Next, the configuration of a cutting tool including the above-described coated tool 1 will be described with reference to Fig. 7. Fig. 7 is a front view showing an example of a cutting tool according to an embodiment.

[0081] As shown in FIG. 7 , a cutting tool 100 according to the embodiment includes a coated tool 1 and a holder 70 for fixing the coated tool 1 .

[0082] The holder 70 is a rod-shaped member extending from a first end (the upper end in FIG. 7 ) to a second end (the lower end in FIG. 7 ). The holder 70 is made of, for example, steel or cast iron. Among these materials, steel, which has high toughness, may be used.

[0083] The holder 70 has a pocket 73 at the end on the first end side. The pocket 73 is a portion where the coated tool 1 is attached, and has a seating surface that intersects with the rotation direction of the workpiece and a constraint side surface that is inclined relative to the seating surface. The seating surface is provided with a screw hole into which a screw 75, which will be described later, is threaded.

[0084] The coated tool 1 is positioned in a pocket 73 of the holder 70 and attached to the holder 70 by a screw 75. That is, the screw 75 is inserted into the through hole 5 of the coated tool 1, and the tip of the screw 75 is inserted into a threaded hole formed in the seating surface of the pocket 73 to screw the threaded portions together. In this way, the coated tool 1 is attached to the holder 70 so that the cutting edge portion protrudes outward from the holder 70.

[0085] In the embodiment, a cutting tool 100 used for so-called turning is exemplified. Examples of turning include internal diameter machining, external diameter machining, and grooving. The cutting tool is not limited to that used for turning. For example, the coated tool 1 may be used as a cutting tool used for milling. Examples of cutting tools used for milling include milling cutters such as flat milling cutters, face milling cutters, side milling cutters, and groove milling cutters, and end mills such as single-blade end mills, multi-blade end mills, tapered-blade end mills, and ball end mills.

[0086] Examples of the present disclosure will be specifically described below, but the present disclosure is not limited to the examples shown below.

[0087] (Example) A coated tool including a substrate and a coating layer consisting of an adhesion layer, an intermediate layer, and a wear-resistant layer was fabricated by sequentially laminating an adhesion layer, an intermediate layer, and a wear-resistant layer onto the substrate using an arc ion plating method. The substrate was a WC-based cemented carbide. The compositions and thicknesses of the adhesion layer, intermediate layer, and wear-resistant layer formed on the substrate are shown in Table 1.

[0088]

[0089] Next, a cross-section of the coating layer, including the intermediate layer and the wear-resistant layer, was photographed in the normal direction to the surface of the substrate using an STEM. Elemental analysis of the coating layer was performed using EDS on the cutting edge of the coated tool. Specifically, elemental analysis of the coating layer was performed for each of the elements aluminum (Al), titanium (Ti), and chromium (Cr).

[0090] Figure 8 is an image showing a cross section of a coating layer in an example. Figure 8A is an image taken by STEM. Figures 8B to 8D are images taken using EDS to show the titanium (Ti), aluminum (Al), and chromium (Cr) contents. The dashed lines attached to Figure 8A are superimposed on Figure 8A, showing the boundaries where the titanium, aluminum, and chromium contents in Figures 8B to 8D change abruptly. This dashed line indicates the boundary between the wear-resistant layer 21 and the intermediate layer 22.

[0091] Next, in an analysis using TEM electron diffraction mapping, an inverse pole figure orientation map of the coating layer in the normal direction to the substrate surface was obtained for the cutting edge of a coated tool produced as an example. Figure 9A is the same as the STEM image shown in Figure 8A. Figure 9B is an image showing the inverse pole figure orientation map of the coating layer at the cutting edge of a coated tool according to the example. The dashed line attached to Figure 9A is the same as the dashed line attached to Figure 8A, and indicates the boundary between the wear-resistant layer 21 and the intermediate layer 22.

[0092] In Figures 8 and 9A, it is possible to show the boundary between the wear-resistant layer 21 and the intermediate layer 22, but it is difficult to show the outlines of the multiple protruding crystals. The outlines of the multiple protruding crystals can be identified by showing an inverse pole figure orientation map of the coating layer, as shown in Figure 9B. In the map shown in Figure 9B, the differences in crystal orientation are shown by color mapping, so that the outlines of the multiple protruding crystals 30 relative to the intermediate layer 22 and the wear-resistant layer 21 can be identified. The solid lines added to Figure 9B indicate the outlines of the multiple protruding crystals.

[0093] The solid line attached to A in Fig. 9 is obtained by superimposing the solid line attached to B in Fig. 9 on A in Fig. 9. This solid line shows the outlines of the multiple protruding crystals in A in Fig. 9. It can be seen from Fig. 9 that the multiple protruding crystals can have a substantially rectangular shape and a substantially triangular shape.

[0094] While it is possible to identify the outlines of the multiple protruding crystals based on B in Fig. 9, it is difficult to identify the outlines of the multiple protruding crystals in the images obtained using EDS, as is clear from B to D in Fig. 8. This shows that the multiple protruding crystals have a region (first region) surrounded by the abrasion-resistant layer 21 and having a first composition similar to that of the abrasion-resistant layer 21, and a region (second region) surrounded by the intermediate layer 22 and having a second composition similar to that of the intermediate layer 22.

[0095] Next, on each of the cutting edge and flank of the coated tool produced as an example, the protruding crystals having a substantially triangular shape found in the coating layer were approximated to protruding crystals having a triangular shape. Protruding crystals having a triangular shape were extracted from the protruding crystals having a substantially quadrangular shape. For such protruding crystals having a triangular shape, the height, inclination angle, and aspect ratio of the protruding crystals were calculated. The values ​​of the height, inclination angle, and aspect ratio of the protruding crystals are shown in Table 2.

[0096]

[0097] As shown in Table 2, it was confirmed that the coated tools according to the examples included a plurality of protruding crystals with a height of 500 nm or more on both the cutting edge and flank of the coated tool. It was confirmed that the plurality of protruding crystals included protruding crystals with an inclination angle of 15 degrees or more and 45 degrees or less with respect to the normal direction of the surface of the base. It was confirmed that the plurality of protruding crystals included protruding crystals with an aspect ratio of 0.1 or more and 1 or less.

[0098] Similarly, a photograph of the cross section of the coating layer including the intermediate layer and the wear-resistant layer taken in the normal direction to the surface of the substrate was taken using a scanning transmission electron microscope for the cutting edge of a conventional coated tool as a comparative example. In the cross section of the coating layer at the cutting edge of the conventional coated tool as a comparative example, it was confirmed that the coating layer did not have protruding crystals at the interface between the intermediate layer and the wear-resistant layer.

[0099] Next, the peel loads were measured for the coated tools according to the Examples and the Comparative Examples. Specifically, the coating layer of each of the coated tools according to the Examples and the Comparative Examples was scratched in a direction parallel to the surface of the substrate. The load applied to the coating layer was changed from 1 N to 25 N at a rate of change of 0.23 N / sec. The minimum load that caused peeling of the intermediate layer and the wear-resistant layer in the coating layer was measured as the peel load. The peel load for the coated tool according to the Examples was 18 N. The peel load for the coated tool according to the Comparative Example was 12 N. Thus, it was confirmed that the peel load for the coated tool according to the Examples was greater than that for the coated tool according to the Comparative Example.

[0100] Therefore, it was confirmed that when the coating layer has multiple protruding crystals at the interface between the intermediate layer and the wear-resistant layer, the adhesion force acting between the intermediate layer and the wear-resistant layer is improved.

[0101] Next, cutting tests were carried out on the coated tools according to the examples and the comparative examples under the following conditions.

[0102] <Cutting test conditions> Workpiece: Inconel (registered trademark) 718 Cutting speed (Vc): 30 m / min Feed (f): 0.1 mm / rev Depth of cut (ap): 0.5 mm Cutting condition: Wet Tool used: CNMG120408SG

[0103] The length of abrasive wear in the thickness direction of the coating layer of the coated tool according to the example (hereinafter referred to as "abrasive wear amount") was measured using an image showing the cutting edge condition of the coated tool according to the example after the cutting test. The cutting times in the cutting test were 7.4 minutes, 14.8 minutes, 19.8 minutes, 24.7 minutes, 29.7 minutes, and 34.6 minutes.

[0104] Similarly, the amount of abrasive wear in the thickness direction of the coating layer of the coated tool according to the comparative example was measured using an image showing the cutting edge condition of the coated tool according to the comparative example after the cutting test. The cutting times in the cutting test were 7.4 minutes and 14.8 minutes.

[0105] Fig. 10 is a graph showing the correlation between cutting time and abrasive wear amount. The horizontal axis of the graph shown in Fig. 10 represents cutting time (minutes). The vertical axis of the graph shown in Fig. 10 represents abrasive wear amount (mm). In the graph shown in Fig. 10, white circles represent measured values ​​for the coated tool according to the example. Black circles represent measured values ​​for the coated tool according to the comparative example.

[0106] 10 , it was confirmed that the abrasive wear amount of the coated tool according to the example was smaller than the abrasive wear amount of the coated tool according to the comparative example at a certain cutting time. In other words, it was confirmed that the cutting time of the coated tool according to the example was longer than the cutting time of the coated tool according to the comparative example at a certain abrasive wear amount.

[0107] Using images showing the cutting edge condition of the coated tool according to the example after the cutting test, the time until the abrasive wear amount of the coated tool according to the example reached 0.2 mm was calculated. The time until the abrasive wear amount of the coated tool according to the example reached 0.2 mm was more than 34.6 minutes. Similarly, using images showing the cutting edge condition of the coated tool according to the comparative example after the cutting test, the time until the abrasive wear amount of the coated tool according to the comparative example reached 0.2 mm was calculated. The time until the abrasive wear amount of the coated tool according to the comparative example reached 0.2 mm was 14.8 minutes. It was confirmed that at a certain abrasive wear amount, the cutting time of the coated tool according to the example was longer than the cutting time of the coated tool according to the comparative example.

[0108] Thus, it was confirmed that when the coating layer has a plurality of protruding crystals at the interface between the intermediate layer and the wear-resistant layer, the wear resistance of the coated tool can be improved, in other words, the tool life of the coated tool can be extended.

[0109] The cutting edge condition of the coated tool after 7.4 minutes of cutting under the above cutting conditions is shown in Figures 11 and 12. Figure 11 is an image showing the cutting edge condition of the coated tool according to the example after the cutting test. Figure 12 is an image showing the cutting edge condition of the coated tool according to the comparative example after the cutting test. In each of Figures 11 and 12, the portion of the cutting edge of the coated tool where the coating layer has been removed by abrasive wear D3 and the substrate has been exposed is indicated by a dotted white circle.

[0110] 11 and 12 , it was confirmed that the abrasive wear D3 of the coated tool according to the example was reduced compared to the abrasive wear D3 of the coated tool according to the comparative example. Therefore, it was confirmed that when the coating layer has a plurality of protruding crystals at the interface between the intermediate layer and the wear-resistant layer, the wear resistance of the coated tool can be improved.

[0111] <Notes> Note (1): A coated tool comprising a substrate and a coating layer located on the substrate, wherein the coating layer has a first layer, a second layer located between the first layer and the substrate and in contact with the first layer, and a plurality of protruding crystals located at the interface between the first layer and the second layer, the plurality of protruding crystals protruding toward the first layer and the second layer, respectively. Note (2): The coated tool according to Note (1), wherein at least one of the plurality of protruding crystals has a first region surrounded by the first layer and a second region surrounded by the second layer, the first region being larger than the second region. Note (3): The coated tool according to Note (1) or (2), wherein at least one of the plurality of protruding crystals has a first region surrounded by the first layer and a second region surrounded by the second layer, the composition of the first region and the composition of the second region being different from each other. Supplementary Note (4): The coated tool according to any one of Supplementary Notes (1) to (3), wherein at least one of the plurality of protruding crystals has a height of 500 nm or more. Supplementary Note (5): The coated tool according to any one of Supplementary Notes (1) to (4), wherein at least one of the plurality of protruding crystals has an inclination angle of 15 degrees or more and 65 degrees or less with respect to the normal direction of the surface of the base. Supplementary Note (6): The coated tool according to any one of Supplementary Notes (1) to (5), wherein at least one of the plurality of protruding crystals has an aspect ratio of 0.1 or more and 1 or less. Supplementary Note (7): The coated tool according to any one of Supplementary Notes (1) to (6), wherein the first layer has a first composition including a metal component containing Ti and Al and at least one element selected from the group consisting of carbon, nitrogen, and oxygen, and the second layer has a second composition including a metal component containing Ti and Al and at least one element selected from the group consisting of carbon, nitrogen, and oxygen, and the first composition and the second composition are different from each other.Supplementary Note (8): The coated tool according to Supplementary Note (7), wherein at least one of the plurality of protruding crystals has a first region surrounded by the first layer and a second region surrounded by the second layer, the first region having the first composition, and the second region having the second composition. Supplementary Note (9): A cutting tool comprising: a rod-shaped holder having a pocket at an end thereof; and the coated tool according to any one of Supplements (1) to (8) positioned in the pocket.

[0112] Further advantages and / or modifications may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0113] REFERENCE SIGNS LIST 1 Coated tool 2 Tip body 5 Through hole 10 Base body 20 Coating layer 21 First layer (wear-resistant layer) 22 Second layer (intermediate layer) 23 Third layer (adhesion layer) 30 Projecting crystal 70 Holder 73 Pocket 75 Screw 100 Cutting tool 201 Corner portion A, B, C Vertex D1 Primary boundary wear D2 Secondary boundary wear D3 Abrasive wear D4 Crater wear H Foot of perpendicular CC Circumscribed circle IC Inscribed circle

Claims

1. a substrate; a coating layer overlying the substrate; Equipped with The coating layer is The first layer, a second layer located between the first layer and the substrate and in contact with the first layer; a plurality of protruding crystals located at the interface between the first layer and the second layer, the plurality of protruding crystals protruding toward the first layer and the second layer, respectively; Coated tools.

2. At least one of the plurality of protruding crystals is a first region surrounded by the first layer; a second region surrounded by the second layer, The first region is larger than the second region. The coated tool according to claim 1 .

3. At least one of the plurality of protruding crystals is a first region surrounded by the first layer; a second region surrounded by the second layer, the composition in the first region and the composition in the second region are different from each other; The coated tool according to claim 1 .

4. At least one of the plurality of protruding crystals has a height of 500 nm or more. The coated tool according to claim 1 .

5. At least one of the plurality of protruding crystals has an inclination angle of 15 degrees or more and 65 degrees or less with respect to the normal direction of the surface of the base body. The coated tool according to claim 1 .

6. At least one of the plurality of protruding crystals has an aspect ratio of 0.1 or more and 1 or less. The coated tool according to claim 1 .

7. The first layer is a metal component including Ti and Al; at least one element selected from the group consisting of carbon, nitrogen, and oxygen; The second layer is a metal component including Ti and Al; at least one element selected from the group consisting of carbon, nitrogen, and oxygen; the first composition and the second composition are different from each other; The coated tool according to claim 1 .

8. At least one of the plurality of protruding crystals is a first region surrounded by the first layer; a second region surrounded by the second layer, the first region has the first composition; the second region has the second composition; The coated tool according to claim 7.

9. a rod-shaped holder having a pocket at an end; The coated tool according to any one of claims 1 to 8, which is located in the pocket; A cutting tool comprising: