Surface-coated cutting tool

Abstract

A surface-coated cutting tool has a cubic crystal structure of stacked layers with an average thickness of 0.5–8.0 μm. The stacked layers are a first layer and a second layer. The first layer is the layer on both the substrate side and the surface side. The first layer has an average thickness of 0.1 μm–2.0 μm and contains (Al) 1‑x Cr x The composition of N and x = 0.20–0.60, the average thickness of the second layer is 0.1 μm–2.0 μm, and it has (Al) 1‑a‑b Cr a Si b The second layer has a composition of N, a = 0.20–0.60, and b = 0.01–0.20. The average interval between the maxima and minima of Si content is 1 nm–100 nm, and the average value of the maxima is Si. max 1.0 < Si max / b≤2.0, the average value of the minimum value Si min 0.0≤Si min When / b < 1.0, the half-width at half-maximum (WHM) of the 111 diffraction peak is 0.1 to 1.0 degrees when summarizing the X-ray diffraction peaks of the first and second layers, and the intensity of the 111 diffraction peak is set to I. 111 Set the diffraction peak intensity of the 200 diffraction line to I. 200 At that time, I 111 / I 200 Greater than 1 and less than 5.

Description

Technical Field

[0001] This invention relates to surface-coated cutting tools (hereinafter, sometimes referred to as coating tools).

[0002] This application claims priority to Japanese Patent Application No. 2020-212386, filed on December 22, 2020. All descriptions in that Japanese patent application are incorporated herein by reference. Background Technology

[0003] In order to improve the life of existing cutting tools, coated tools have a coating layer formed on the surface of a substrate such as tungsten carbide (hereinafter referred to as WC)-based cemented carbide, and the wear resistance of the coated tools is improved.

[0004] Furthermore, in order to further improve the cutting performance of coated tools, many proposals have been put forward regarding the composition and structure of the coating layer.

[0005] For example, Patent Document 1 describes a coating tool in which (AlCrSi)(NOBC) is used as the coating layer, and the half-width of the diffraction peaks of the 111 or 200 plane is set to 0.5 to 2.0 degrees. In the coating layer, there is more oxygen at the grain interface compared with the inside of the grain, and the wear resistance of the coating tool is improved.

[0006] Furthermore, for example, Patent Document 2 describes a coating tool as follows: the coating layer is an alternating layer of a first layer of (AlCrSi)N and a second layer of (TiSi)N. When the peak intensity of the 111 diffraction line of the first layer is set as Ir, the peak intensity of the 200 diffraction line is set as Is, and the peak intensity of the 220 diffraction line is set as It, Is / Ir = 1~10 and It / Ir = 0.6~1.5. When the surface spacing of the 200 diffraction lines of the first layer and the second layer is set as d1 and d2, 0.965≤d1 / d2≤0.990. The second layer with columnar crystal structure has a repeating variation in Si content. This coating tool has excellent wear resistance.

[0007] Furthermore, for example, Patent Document 3 describes a coating tool with an average thickness of 4–10 μm, comprising a first layer of (AlCr)N and a second layer of (TiSi)N. The first layer has a half-width of 0.7–1.1 degrees for the 111 diffraction line, and when the peak intensity of the 111 diffraction line is set to Ir, the peak intensity of the 200 diffraction line is set to Is, and the peak intensity of the 220 diffraction line is set to It, 0.3 ≤ Is / Ir ≤ 1.0 and 0.3 ≤ It / Ir < 1. The second layer has a half-width of 0.6–1.1 degrees for the 111 diffraction line, and when the peak intensity of the 111 diffraction line is set to Iu, the peak intensity of the 200 diffraction line is set to Iv, and the peak intensity of the 220 diffraction line is set to Iw, 0.3 ≤ Iv / Iu < 1 and 0.3 ≤ Iw / Iu < 1. This coating tool exhibits excellent wear resistance.

[0008] Furthermore, for example, Patent Document 4 describes a coating tool in which a first layer of (AlCr)N and a second layer of (TiSi)N are alternately stacked as a coating layer, each of the first and second layers having a thickness of 1 to 20 nm, and a mixed structure having a mixture of the components of the first and second layers comprising 5 to 80% of the total cross-sectional area of ​​the coating layer. This coating tool exhibits excellent wear resistance.

[0009] Patent Document 1: Japanese Patent Publication No. 2005-126736

[0010] Patent Document 2: Japanese Patent Publication No. 2011-93085

[0011] Patent Document 3: Japanese Patent Publication No. 2012-45650

[0012] Patent Document 4: Japanese Patent No. 5087427 Summary of the Invention

[0013] The present invention was made in view of the above circumstances and the above proposal, and its object is to provide a surface-coated cutting tool with excellent wear resistance and chip resistance.

[0014] The surface-coating cutting tool involved in the embodiments of the present invention is described below.

[0015] 1) The surface-coated cutting tool is a tool having a substrate and a coating layer on the surface of the substrate.

[0016] 2) The average thickness of the coating layer is 0.5 μm or more and 8.0 μm or less, and the coating layer has a laminated body consisting of one or more first layers and one or more second layers alternately stacked.

[0017] 3) The layer closest to the substrate and the layer closest to the surface of the tool in the laminate are both the first layer.

[0018] 4) The average thickness of the first layer is greater than 0.1 μm and less than 2.0 μm, and the first layer has (Al) 1- x Cr x The average composition of N (0.20≤x≤0.60),

[0019] 5) The average thickness of the second layer is greater than 0.1 μm and less than 2.0 μm, and the second layer has (Al) 1-a- b Cr a Si b The average composition of N (0.20≤a≤0.60, 0.01≤b≤0.20), the second layer has repeated variations in Si content with an average interval of more than 1 nm and less than 100 nm between adjacent maxima and minima, and the average value of the Si content maxima is Si max 1.0 < Si max / b≤2.0, and the average value of the minimum Si content is Si min 0.0≤Si min / b<1.0,

[0020] 6) Both the first and second layers have NaCl-type face-centered cubic grains.

[0021] 7) When summarizing the X-ray diffraction peaks of the first and second layers, the full width at half maximum (FWHM) of the 111 diffraction peak is greater than 0.1 degrees and less than 1.0 degrees, and the intensity of the 111 diffraction peak is set to I. 111 Set the diffraction peak intensity of the 200 diffraction line to I. 200 At that time, I 111 / I 200 Greater than 1.0 and less than 5.0.

[0022] Furthermore, the surface-coating cutting tool involved in the aforementioned embodiments may also satisfy one or more of the following (1) or (2) or the following (2) and (3) or all of the following (1) to (3).

[0023] (1) A third layer is formed by replacing the first layer of the laminated body layers on the surface closest to the tool, the average composition of the third layer being (Al). 1-y Cr y)N(0.20≤y≤0.60), the average thickness of the third layer is greater than 0.3μm and less than 4.0μm, and the average thickness of the third layer is greater than the average thickness of the other first layers of the laminate.

[0024] (2) The first or third layer of the laminated body has a surface layer on the tool surface side, the surface layer having an average thickness of 0.1 μm or more and 4.0 μm or less, and the surface layer having an average composition of (Ti) 1-α-β Si α W β )N(0.01≤α≤0.20, 0.01≤β≤0.10),

[0025] The surface layer has repeated variations in W content with an average interval of more than 1 nm and less than 100 nm between adjacent maxima and minima, and the average value of the maxima of the W content is W. max 1.0 < W max / β≤2.0, and the average value of the minimum value of the W content W min For 0.0≤W min / β<1.0.

[0026] (3) An intermediate layer is provided between the first or third layer on the surface side of the laminate closest to the tool and the surface layer, the intermediate layer having an average thickness of 0.1 μm or more and 2.0 μm or less, and the intermediate layer having an average composition of (Al). 1-k-l-m-n Ti k Cr l Si m W n )N(0.20≤k≤0.65, 0.10≤l≤0.35, 0.00<m≤0.15, 0.00<n≤0.05),

[0027] The intermediate layer has repeated variations in Si content with an average interval of more than 1 nm and less than 100 nm between adjacent maxima and minima, and the average value of the Si content maxima is Sim. max 1.0 < Sim max / m≤2.0, and the average value of the minimum value of the Si content Sim min =0.0≤Sim min / m<1.0.

[0028] The aforementioned surface-coated cutting tools exhibit excellent wear resistance and chip resistance. Attached Figure Description

[0029] Figure 1This is a schematic diagram showing a longitudinal cross-section of the coating layer of a surface-coated cutting tool according to an embodiment of the present invention.

[0030] Figure 2 This is a partial diagram schematically illustrating an example of the repeated variation of Si content in the longitudinal section of the coating layer of a surface-coated cutting tool according to an embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram showing a longitudinal section of the coating layer of a surface-coated cutting tool according to another embodiment of the present invention.

[0032] Figure 4 The results are X-ray diffraction measurements of the coating layer in Example 4.

[0033] Figure 5 The results are X-ray diffraction measurements of the coating layer in Example 14.

[0034] Figure 6 This is a schematic top view of the arc ion plating apparatus used in Examples A and B to form the coating layer.

[0035] Figure 7 yes Figure 6 A schematic front view of the arc ion plating apparatus. Detailed Implementation

[0036] The inventors have studied composite nitride layers of Al, Cr, and Si (hereinafter sometimes referred to as (AlCrSi)N). The results revealed the following problems: Al improves high-temperature hardness and heat resistance, Cr improves high-temperature strength, and if Al and Cr coexist, high-temperature oxidation resistance also improves. Furthermore, although Si improves heat resistance, the lattice distortion of the (AlCrSi)N layer increases due to the presence of Si. Therefore, under high loads, the (AlCrSi)N layer does not possess sufficient toughness to withstand this lattice distortion, making it prone to chipping and breakage.

[0037] Furthermore, the inventors have discovered the following problem: if the aforementioned coating layer is formed by simply stacking the (AlCrSi)N layer and other known coating layers (e.g., a composite nitride layer of Ti and Si), in addition to the low toughness of the (AlCrSi)N layer itself, the toughness will be further reduced when viewed as a whole due to the distortion caused by the mismatch of the lattice constant at the interface with such other hard phases, making it difficult to avoid chipping and damage.

[0038] Therefore, the inventors conducted further research. As a result, the following new insights were obtained: by setting the composition of the (AlCrSi)N layer within a specified range, and forming other coating layers with excellent adhesion to both the substrate and the (AlCrSi)N layer, i.e., forming a laminated structure of a composite nitride of Al and Cr (hereinafter, sometimes referred to as (AlCr)N) layer, and by giving the (AlCrSi)N layer a specified XRD pattern,

[0039] Furthermore, based on this layered structure and XRD pattern, a composite nitride layer of Ti, Si, and W (hereinafter sometimes referred to as (TiSiW)N) is layered to impart repeating variations to the Si content.

[0040] Furthermore, selectively stacking composite nitrides of Al, Ti, Cr, Si, and W (hereinafter sometimes referred to as (AlTiCrSiW)N) layers imparts repeatable variations to the W content.

[0041] This improves the adhesion between the coating layer and the substrate, as well as the adhesion between each layer, achieving high overall toughness of the coating layer. For example, even under harsh cutting conditions (hereinafter sometimes referred to as high-load cutting conditions) with continuous and intermittent cutting processes applied in combination, it can maintain excellent wear resistance for a long time and obtain coated tools that suppress chipping and damage.

[0042] The coating tool according to the embodiments of the present invention will be described in detail below.

[0043] In this embodiment, film formation is performed without any layers other than the first to fifth layers. When the layers to be formed are changed (to form films on other adjacent layers), pressure fluctuations inevitably occur within the film formation apparatus. Sometimes, layers containing unintentional oxygen and carbon with different compositions than these layers are formed between the adjacent layers.

[0044] Furthermore, in this specification and claims, when the range of values ​​is expressed as “L~M” (where L and M are both numerical values), the range includes an upper limit (M) and a lower limit (L). When only the unit of the upper limit (M) is specified, the units of the upper limit (M) and the lower limit (L) are the same.

[0045] I. Figure 1 The implementation method shown

[0046] Figure 1 The diagram schematically illustrates a longitudinal section of a surface-coated cutting tool according to one embodiment of the present invention. Therefore, firstly... Figure 1 The embodiments shown will be described.

[0047] In addition, the longitudinal section refers to the section that ignores the minor unevenness of the substrate surface and is perpendicular to the substrate surface.

[0048] 1. Coating layer

[0049] In this embodiment, by Figure 1 It is understood that the coating layer has a first layer 2 on the substrate 1, and has a laminated layer formed by alternating layers of the first layer 2 and the second layer 3. In addition, as described later, a third layer 4 may also be provided on the outermost surface side (tool surface side) of the coating tool (i.e., it may be the first layer instead of the third layer). Figure 1 This describes an implementation where a third layer 4 is provided instead of a first layer 2 on the surface side of the tool.

[0050] (1) First layer

[0051] In the first layer of the laminate consisting of Al and Cr, namely the (AlCr)N layer, Al has the function of improving high-temperature hardness and heat resistance, while Cr has the function of improving high-temperature strength. Furthermore, when Cr and Al coexist, they have the function of improving high-temperature oxidation resistance.

[0052] In the formula: (Al) 1-x Cr x When )N represents the average composition of the first layer of the (AlCr)N layer, it is preferable that the x-value of the Cr content is 0.20 or more and 0.60 or less. The reason is that when the x-value is less than 0.20, the high-temperature strength decreases, leading to a deterioration in chipping resistance, and the relatively increased Al content results in hexagonal grains, thus reducing hardness and wear resistance. On the other hand, when the x-value is greater than 0.60, the relatively decreased Al content fails to ensure sufficient high-temperature hardness and heat resistance, resulting in reduced wear resistance. A more preferred range for the x-value is 0.25 or more and 0.50 or less.

[0053] Furthermore, according to one example of the manufacturing method described later, although it is manufactured with a (AlCr) to N ratio of 1:1, sometimes it is unavoidable (unintentionally) that the ratio is not 1:1. This situation also exists for other complex nitrides described below.

[0054] (2) Second layer

[0055] In the (AlCrSi)N layer, which forms the second layer of the laminate together with the first layer, Cr, similar to the first layer, improves the high-temperature strength and the chipping resistance of the coating layer. Furthermore, by being present in the presence of Al, it also helps to improve the high-temperature oxidation resistance and wear resistance.

[0056] In addition, Si, as a component of the second layer, has the effect of improving heat resistance and heat-resistant plastic deformation, but it also increases the lattice distortion of the second layer, which results in a decrease in the chipping resistance of the second layer. Therefore, the content of Si is repeatedly varied as described later.

[0057] In the formula: (Al) 1-a-b Cr a Si b When 'N' represents the average composition of the second layer of the (AlCrSi)N layer, it is preferable that the 'a' value of the Cr content is 0.20 or higher and 0.60 or lower. This is because when the 'a' value is less than 0.20, the high-temperature strength decreases, leading to a deterioration in chipping resistance, and the relatively increased Al content results in hexagonal grains, thus reducing hardness and wear resistance. On the other hand, when the 'a' value is greater than 0.60, the relatively decreased Al content fails to ensure sufficient high-temperature hardness and heat resistance, resulting in reduced wear resistance. A more preferred range for the 'a' value is 0.25 or higher and 0.50 or lower.

[0058] Furthermore, the b-value is preferably 0.01 or higher and 0.20 or lower. This is because when the b-value is less than 0.01, the improvement in heat resistance and heat-resistant plastic deformation of the second layer decreases. On the other hand, when the b-value is greater than 0.20, a tendency to decrease the improvement in wear resistance is observed. Simultaneously, the increased lattice distortion in the second layer leads to a greater lattice mismatch between the first and second layers, resulting in a decrease in chipping resistance, particularly under high-load cutting conditions. A more preferred range for the b-value is 0.01 or higher and 0.15 or lower.

[0059] Furthermore, to more effectively reduce lattice distortion, regarding the Si content, it is preferable to have a repeating variation of Si content with an average interval of adjacent maxima and minima (i.e., the average interval in the direction perpendicular to the substrate surface (thickness direction, defined later)) of 1 nm or more and 100 nm or less. That is, it is inferred that this repeating variation suppresses abrupt changes in Si content between the first and second layers, more effectively reducing lattice distortion. This results in improved adhesion between the two layers, prevention of peeling of the coating layer, and improved resistance to chipping and damage.

[0060] Specifically, regarding the Si content, the reason for setting the average interval between adjacent maxima and minima to be 1 nm or more and 100 nm or less is that when the average interval is less than 1 nm, the Si content changes drastically, resulting in increased local lattice distortion and decreased resistance to chipping. On the other hand, when the average interval is greater than 100 nm, the Si content increases, meaning the region with large lattice distortion widens, making it easier for chipping to originate from this region, thus reducing resistance to chipping. A more preferred range for the repeating average interval is 5 nm or more and 50 nm or less.

[0061] Figure 2 This is a partial graph schematically illustrating a repeating variation of Si content. Figure 2 In this specification and claims, the maximum and minimum values ​​are the same, and the interval between adjacent maximum and minimum values ​​is also the same. As long as the repeated change of Si content mentioned in this specification and claims refers to the Si content changing in a way that alternates between taking maximum and minimum values, the maximum and minimum values ​​can be the same or different values, and the interval between adjacent maximum and minimum values ​​can also be the same or different.

[0062] Furthermore, when the average of the maximum Si content is set as Si max When, preferably 1.0 < Si max / b≤2.0, and furthermore, the average value of the minimum Si content is set as Si min When, preferably, 0.0 ≤ Si min / b < 1.0. Here, b is the average Si content in the second layer.

[0063] As specified above, the ratio of the maximum value of Si to the average value of b is defined. max / b and the ratio of the average of the minimum values ​​to b, Si min The reason for / b is that, in Si max / b is greater than 1.0, and Si min When / b is less than 1.0, although a reduction in lattice distortion caused by repeated changes in Si content can be obtained, in Si max When / b is greater than 2.0, the composition changes more drastically, resulting in a sharp change in Si content, which reduces the chipping resistance.

[0064] Si max / b、Si min The more preferred range for / b is 1.2 < Si. max / b≤2.0、0.0≤Si min / b<0.8.

[0065] Here, the average interval between the location of the maximum value of Si and the location of the adjacent minimum value in the second layer with repeated variations in Si content is determined by measuring the Si content in the thickness direction of the second layer and performing known measurement noise removal to visualize it.

[0066] That is, such as Figure 2 As shown, a straight line m (in) is plotted across the curve representing the repeated changes in Si content. Figure 2In this diagram, the straight line *m* represents the length traversing the two maxima and minima, but the length of *m* is not limited to this (the length is used to accurately calculate the average of the maxima and minima, as well as the average interval). The straight line *m* is drawn such that the area of ​​the region enclosed by the curve is equal on both the upper and lower sides of the line *m*. Then, for each region traversed by the straight line *m* representing the repeated changes in Si content, the maxima or minima of Si content are calculated, and the interval between them is measured. By averaging these measurements across multiple locations, the average interval of the repeated changes in Si content in the second layer is determined.

[0067] Furthermore, by averaging the measured values ​​of the maximum and minimum Si content at multiple locations, the average value of the maximum Si content was calculated. max The average value of the minimum Si content min .

[0068] (3) Laminated layers

[0069] A laminate is a layer formed by alternating layers of the first and second layers.

[0070] The average thickness of the first and second layers is preferably 0.1 μm or more and 2.0 μm or less, respectively. Within this average thickness range, the lattice mismatch between the first and second layers is mitigated, improving the chipping resistance and wear resistance of the coating layer. Furthermore, as described later, the first layer of the laminate closest to the surface of the tool being coated can be replaced with a third layer. Replacing it with a third layer makes it more practical to achieve the aforementioned objectives.

[0071] Furthermore, it is preferable to construct a laminate with an average thickness of 0.5 μm or more and 8.0 μm or less by alternately stacking the first and second layers. This is because when the average thickness of the laminate is less than 0.5 μm, the laminate cannot maintain sufficient wear resistance over a long period of time; on the other hand, when the average thickness is greater than 8.0 μm, abnormal damage such as chipping, breakage, and peeling is more likely to occur. A more preferred range for this average thickness is 1.0 μm or more and 7.0 μm or less.

[0072] Furthermore, even when the laminate has the third to fifth layers described later, the preferred range of the average thickness of the laminate (the average thickness of the laminate as a whole) is the same as when the laminate consists of only the first and second layers.

[0073] Preferably, both the layer closest to the substrate and the layer closest to the surface of the tool being coated are the first layers of the laminate. This is because forming the first layer on the substrate side ensures strong adhesion between the substrate and the laminate, and forming the first layer on the surface of the tool being coated ensures the laminate's resistance to chipping during high-load cutting.

[0074] Here, regarding the number of layers of the first and second layers, there are no particular restrictions as long as the first layer is the side of the laminate closest to the substrate and the side of the laminate closest to the surface of the covering tool, the average thickness of the first and second layers is 0.1 μm or more and 2.0 μm or less respectively, and the total thickness of the laminate is 0.5 μm or more and 8.0 μm or less. More preferably, the number of layers of the first and second layers is 3 to 6, for example, the number of layers of the first layer is 5 and the number of layers of the second layer is 4.

[0075] Furthermore, the first layer on the surface closest to the covering tool of the laminated body can also be replaced by a third layer (or not necessarily a third layer). In the formula: (Al) 1-y Cr y When N represents the average composition of the third layer, the atomic ratio y is greater than or equal to 0.20 and less than or equal to 0.60 (y may be the same as or different from x), the average thickness of the third layer is greater than or equal to 0.3 μm and less than or equal to 4.0 μm, and the average thickness of the third layer is greater than the average thickness of the other first layers of the laminate.

[0076] The reason for this is that by making the third layer, which is a (AlCr)N layer with a relatively small lattice distortion ratio compared to the second layer closest to the tool surface, thicker than the first layer and placing it on the tool surface of the laminated layer, impact mitigation during high-load cutting is further improved. When the average thickness of the (AlCr)N layer on the tool surface is less than 0.3 μm, it is not sufficient to further improve chipping resistance; on the other hand, when it is greater than 4.0 μm, the proportion of the (AlCr)N layer in the hard coating layer (laminated layer) increases, and wear resistance decreases. A more preferred range for the y-value of the third layer is 0.25 or more and 0.50 or less. Furthermore, a more preferred range for this average thickness is 0.5 μm or more and 2.0 μm or less.

[0077] (4) NaCl-type face-centered cubic grains

[0078] The grains constituting the first, second, and third layers are preferably NaCl-type face-centered cubic structures. Additionally, these layers may contain an unavoidable (unintentional) amount of grains with crystal structures other than NaCl-type face-centered cubic structures.

[0079] (5) XRD pattern

[0080] When summarizing the X-ray diffraction peaks of the first, second, and third layers, the full width at half maximum (FWHM) of the 111 diffraction peak is greater than 0.1 degrees and less than 1.0 degrees, and the intensity of the 111 diffraction peak is set to I. 111 Set the diffraction peak intensity of the 200 diffraction line to I. 200 When, I is preferred 111 / I 200 Greater than 1.0 and less than 5.0. More preferably, the full width at half maximum (FWHM) of the diffraction peak of the 111 diffraction line is greater than 0.1 degrees and less than 0.5 degrees, and I 111 / I 200 Greater than 1.1 and less than 4.0.

[0081] When the full width at half maximum (FWHM) is within the above range, and I 111 / I 200 Within the aforementioned range, the laminate exhibits excellent chipping resistance and wear resistance. The reasons for this are uncertain, but are speculated as follows: by keeping the full width at half maximum (FWHM) within the aforementioned range, the crystallinity of the laminate increases, and the difference in lattice constants between the crystals constituting the first, second, and third layers decreases. This reduces distortion caused by lattice mismatch at the lamination interfaces of the first, second, and third layers, thus improving wear resistance and chipping resistance. Furthermore, regarding the peak intensity ratio, it is speculated that the preferential presence of the (111) facet, which is the densest facet of the NaCl-type face-centered cubic structure, further enhances wear resistance.

[0082] Here, "summarizing the X-ray diffraction peaks of the first and second layers" refers to the X-ray diffraction peaks obtained by measuring the first and second layers in a superimposed state, rather than separately, during X-ray diffraction of the first and second layers. Similarly, "summarizing the X-ray diffraction peaks of the first, second, and third layers" refers to the X-ray diffraction peaks obtained by measuring the first, second, and third layers in a superimposed state, rather than separately, during X-ray diffraction of the first, second, and third layers.

[0083] 2. Matrix

[0084] (1) Material

[0085] If the substrate material is a conventionally known substrate material, any material can be used as long as it does not hinder the achievement of the purpose of this invention. As an example, preferred materials include cemented carbide (WC-based cemented carbide, which includes Co in addition to WC, and further includes alloys of carbonitrides such as Ti, Ta, and Nb), cermet (ceramics with TiC, TiN, TiCN, etc. as the main components), ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, alumina, etc.), cBN sintered body, or diamond sintered body.

[0086] (2) Shape

[0087] The shape of the substrate is not particularly limited as long as it is used as a cutting tool; examples include the shape of a cutting blade and the shape of a drill bit.

[0088] 3. Manufacturing method

[0089] Regarding the manufacturing method of this embodiment, for example, a film-forming method using PVD can be shown below.

[0090] An electric arc discharge is generated between the Al-Cr alloy target and the anode electrode to form a first layer with a specified average thickness. Then, simultaneously with this electric arc discharge, an electric arc discharge is generated between the Al-Cr-Si alloy target and the anode electrode under specified film formation conditions (controlling the rotation speed of the rotary table, the nitrogen pressure during the electric arc discharge, the bias voltage, and the temperature inside the PVD film formation apparatus, respectively) to form a second layer with repeatedly varying Si content.

[0091] After forming a second layer with a specified average thickness, the arc discharge between the Al-Cr-Si alloy target and the anode electrode is stopped, and the first layer with a specified average thickness is formed only through the arc discharge between the Al-Cr alloy target and the anode electrode.

[0092] Then, this operation is repeated to form a film of a first and second stacked layer with a specified number of layers. Additionally, a third layer may be added. Furthermore, when forming (AlCr)N layers with different average compositions in the first and third layers, an Al-Cr alloy target for forming the third layer is used in addition to the Al-Cr alloy target for forming the first layer.

[0093] Here, the specified X-ray diffraction pattern of this embodiment can be obtained by controlling the alloy composition of the target and the film formation conditions used in the formation of the first, second and third layers to specified values.

[0094] Furthermore, the formation of the second layer does not generate an arc discharge between the Al-Cr alloy target and the anode electrode. By adjusting the film formation conditions, the second layer can also be formed in the case of a separate arc discharge between the Al-Cr-Si alloy target and the anode electrode.

[0095] However, in terms of controlling the repetitive variation of Si content and X-ray diffraction pattern, the method of film formation using an Al-Cr alloy target is superior to the method of film formation using only an Al-Cr-Si alloy target.

[0096] II. Figure 3 The implementation method shown

[0097] Figure 3 The diagram schematically illustrates a longitudinal section of a surface-coated cutting tool according to another embodiment of the present invention. Therefore, for... Figure 3 The embodiments shown will be described. Furthermore, regarding... Figure 1 The repeated parts of the description of the embodiments shown will not be described in detail.

[0098] 1. Coating layer

[0099] (1) Laminated layers and their constituent layers

[0100] This embodiment has the same Figure 1 The stacked layer having the same first layer 2, second layer 3 and selectively having a third layer 4 as the embodiment shown, selectively having a surface layer (fourth layer) 5 on the tool surface side of the stacked layer, and selectively having an intermediate layer (fifth layer) 6 between the surface layer 5 and the third layer 4. Figure 3 This indicates an implementation that selectively includes a third, fourth, and fifth layer.

[0101] Here, "selectively having layer A" means that layer A may or may not be present. For example, layer 4 can be replaced by layer 2, which is the first layer.

[0102] (2) Surface layer

[0103] In this embodiment, a surface layer (fourth layer) is further provided on the surface side of the first or third layer closest to the tool surface of the laminate, the surface layer (fourth layer) having a prescribed composition and structure of a composite nitride of Ti, Si and W (hereinafter sometimes referred to as (TiSiW)N).

[0104] The surface layer is mainly composed of Ti and contains Si, which further improves the oxidation resistance and thermoplastic deformation resistance of the coating. In addition, the surface layer contains W, which further improves the high temperature strength and wear resistance of the coating.

[0105] The average thickness of the surface layer is preferably 0.1 μm or more and 4.0 μm or less. The reason for setting the average thickness within this range is that, for example, under high-load cutting conditions, the chipping resistance, damage resistance, and wear resistance of the coating layer can be further improved. A more preferred range for the average thickness is 0.1 μm or more and 2.0 μm or less.

[0106] Here, in the formula: (Ti) 1-α-β Si α W β When N represents the average composition of the surface layer (fourth layer), it is preferably 0.01≤α≤0.20 and 0.01≤β≤0.10.

[0107] The reason for setting α in this range is that when it is less than 0.01, the improvement in the oxidation resistance and thermoplastic deformation resistance of the surface layer is small. On the other hand, when α is greater than 0.20, the lattice distortion increases, which makes the surface layer prone to self-destruction under high-load cutting conditions.

[0108] Furthermore, the reason for setting β in this range is that when it is less than 0.01, the strength enhancement effect at high temperatures brought by the surface layer is reduced. On the other hand, when β is greater than 0.10, the lattice distortion increases, thereby reducing the chipping resistance of the surface layer in high-load cutting.

[0109] Furthermore, the W content exhibits a repeating variation with an average interval of more than 1 nm and 100 nm between adjacent maxima and minima. The average value of the maxima of the W content is set as W. max When the value is less than W, it is preferable that 1.0 < W. max / β≤2.0, where the average of the minimum values ​​of the W content is set as W min When, preferably 0.0 ≤ W min / β<1.0. Here, β is the average composition β of W in the formula for the surface layer (fourth layer).

[0110] The reason why the average interval between adjacent maxima and minima is preferably 1 nm or more and 100 nm or less is that when the average interval is less than 1 nm, the W content changes drastically, resulting in a local increase in lattice distortion in the surface layer, which reduces the chipping resistance of the coating layer. On the other hand, when the average interval is greater than 100 nm, the W content increases, meaning the region with large lattice distortion in the surface layer widens, making it easier for chipping to start from this region, thus reducing the chipping resistance of the coating layer. The average interval for repeated variations is more preferably 5 nm or more and 50 nm or less.

[0111] In addition, the ratio of the average of the maximum values ​​of W content to β is W max / β and the ratio of the average of the minimum values ​​to β, W min The reason for setting / β to the above range is because, in W max / β is greater than 1.0, and W min When / β is less than 1.0, although it can reduce the lattice distortion of the surface layer caused by repeated changes in composition, in W max When / β is greater than 2.0, the compositional variation becomes larger, resulting in a sharp change in W content, which reduces the chipping resistance of the surface layer. max / β and W min / β is more preferably 1.2 < W max / β≤2.0、0.0≤W min / β<0.8.

[0112] Furthermore, for repeated variations in W content, the average interval, W max and W min The determination and basis Figure 2 The repeated variations in Si content used for illustration are similar. That is, in Figure 2 In the middle, simply replace Si with W.

[0113] (3) Intermediate layer

[0114] In this embodiment, an intermediate layer (fifth layer) may be provided between the first layer on the surface side of the laminate closest to the coated tool, or between the third layer and the surface layer (fourth layer). This intermediate layer (fifth layer) has a prescribed composition and structure of a composite nitride of Al, Ti, Cr, Si, and W (hereinafter sometimes represented as (AlTiCrSiW)N). In this embodiment, the presence of the intermediate layer is optional and not indispensable. That is, the intermediate layer may or may not be present. If the intermediate layer is present, the chipping resistance, chipping resistance, and wear resistance of the coating layer will be further improved.

[0115] The average thickness of the intermediate layer is preferably 0.1 μm or more and 2.0 μm or less. The reason for setting the average thickness within this range is that when the average thickness is less than 0.1 μm, the effect of improving adhesion with the surface layer or the first and third layers cannot be sufficiently obtained; on the other hand, when the average thickness is greater than 2.0 μm, the lattice distortion within the intermediate layer increases, which in turn reduces the adhesion with adjacent layers. A more preferred range for the average thickness is 0.1 μm or more and 1.0 μm or less.

[0116] Here, in the formula: (Al) 1-k-l-m-n Ti k Cr l Si m W n When N represents the average composition of the intermediate layer, it is preferably 0.20≤k≤0.65, 0.10≤l≤0.35, 0.00<m≤0.15, and 0.00<n≤0.05.

[0117] Next, the reasons for determining this range of components will be explained.

[0118] Al, as a component of the interlayer, improves its high-temperature hardness and heat resistance; Ti improves its high-temperature hardness and strength; Cr improves its high-temperature strength and lubricity; and Si improves its oxidation resistance and thermoplastic deformation resistance. Further addition of W further enhances the high-temperature strength and wear resistance of the interlayer.

[0119] When the Ti content is less than 0.20%, the high-temperature hardness and high-temperature strength of the intermediate layer cannot be fully obtained. The Al content is relatively higher, and hexagonal grains are easily formed in the intermediate layer, which reduces the adhesion between the intermediate layer and the first, third, and surface layers. On the other hand, when the Ti content is greater than 0.65%, the content of other components is relatively lower, and the wear resistance of the intermediate layer cannot be fully obtained. A more preferred range for the Ti content is 0.20 or more and 0.50 or less.

[0120] When the Cr content is less than 0.10%, the high-temperature strength and lubricity of the intermediate layer cannot be sufficiently obtained. On the other hand, when the Cr content is greater than 0.35%, the content of other components becomes relatively low, and the wear resistance of the intermediate layer cannot be sufficiently obtained. A more preferred range for the Cr content is 0.10 or more and 0.25 or less.

[0121] When the Si content is 0.00 (without Si), the oxidation resistance and plastic deformation resistance of the intermediate layer cannot be sufficiently obtained, and the adhesion with the first and third layers cannot be sufficiently obtained, thus reducing the adhesion strength. On the other hand, when the Si content is greater than 0.15, the lattice distortion in the intermediate layer becomes larger, and the adhesion strength with the first, third, or surface layers decreases. A more preferred range for the Si content is 0.03 or more and 0.15 or less.

[0122] When the W content is 0.00 (excluding W), the high-temperature strength of the intermediate layer is insufficient. On the other hand, when the W content is greater than 0.05, the lattice distortion in the intermediate layer increases, and the adhesion with the surface layer decreases. A more preferred range for the W content is 0.01 or more and 0.05 or less.

[0123] Furthermore, it is preferable that the intermediate layer has a repeating variation in Si content with an average interval of 1 nm or more and 100 nm between adjacent maxima and minima. Additionally, the average value of the Si content maxima is set to Sim. max When, preferably 1.0 < Sim max / m≤2.0, and the average of the minimum values ​​of the Si content is set as Sim min When the value is 0.0 ≤ Sim, it is preferred. min / m<1.0

[0124] The reason why the average interval between adjacent maxima and minima is preferably 1 nm or more and 100 nm or less is as follows: When the average interval is less than 1 nm, the Si content changes drastically, so the coating layer is prone to chipping, and the adhesion enhancement effect with the surface layer and the first and third layers cannot be fully obtained. On the other hand, when the average interval is greater than 100 nm, the Si content is high, that is, the region with large lattice distortion becomes wider, so chipping is prone to occur starting from this region, and the adhesion enhancement effect cannot be fully obtained. The range of the repeating average interval is more preferably 5 nm or more and 50 nm or less.

[0125] In addition, the ratio of the average of the maximum Si content to m, Sim max / m and the ratio of the average of the minimum values ​​to m (Sim) min The reason for setting / m to the above range is because, although in Sim max / m is greater than 1.0, and Sim min When / m is less than 1.0, repeated changes in Si content occur, but in Sim max When / m is greater than 2.0, the change in Si content becomes larger, resulting in a sharp change in Si content, which reduces the chipping resistance of the coating layer.

[0126] Furthermore, the crystal structure of the grains constituting the fourth and fifth layers is preferably a NaCl-type face-centered cubic structure. Also, similar to the first, second, and third layers, these layers may contain an unavoidable (unintentional) amount of grains with crystal structures other than the NaCl-type face-centered cubic structure.

[0127] In addition, Figure 3 The embodiment shown illustrates a case with a third layer and an intermediate layer (fifth layer), but this embodiment is not limited to this and may also not have a third layer and / or an intermediate layer (fifth layer).

[0128] 2. Matrix

[0129] The material and shape of the substrate and in Figure 1 The content described in the illustrated embodiments is the same.

[0130] 3. Manufacturing method

[0131] The first, second, and third layers are in Figure 1 The content described in the illustrated embodiments is the same.

[0132] (1) Surface layer (fourth layer)

[0133] Regarding the formation of surface layers, for example, a film formation method using PVD can be shown below.

[0134] That is, it is possible to generate repeated changes in W content by simultaneously generating arc discharge between two Ti-Si-W alloy targets with different compositions and the anode electrode, and by adjusting the film formation conditions.

[0135] In addition, similar to the second layer, it is also possible to generate a single electric arc by using a single Ti-Si-W alloy target and adjusting the film formation conditions to achieve repeated variations in W content.

[0136] (2) Intermediate layer (fifth layer)

[0137] Regarding the formation of the intermediate layer, for example, a film formation method using PVD can be shown below.

[0138] That is, an intermediate layer can be formed by generating an arc discharge between the Al-Cr-Si alloy target and the Ti-Si-W alloy target and the anode electrode under specified film-forming conditions.

[0139] Furthermore, the combination of targets is not limited to the combination of Al-Cr-Si alloy targets and Ti-Si-W alloy targets. As long as the target imparts the desired structure to the intermediate layer, it can be a combination of Al-Cr alloy targets and Ti-Si-W alloy targets, or a combination of three or more such targets, including Al-Cr-Si alloy targets, Al-Cr alloy targets, and Ti-Si-W alloy targets.

[0140] III. Measurement Method

[0141] 1. Determination of average composition, interlayer interfaces, and average thickness of each layer.

[0142] By using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS), the longitudinal section was measured and the average value of the measured values ​​was taken to determine the content of the components constituting each layer.

[0143] Here, the surface of the substrate refers to the baseline of the interface roughness between the substrate and the coating layer in the cross-sectional observation image. That is, when the substrate has a planar surface, such as a cutting tool, the interface between the first layer and the substrate is determined by performing element mapping using EDS in the longitudinal section, performing known image processing on the obtained element mapping, and then arithmetically calculating the average line of the roughness curve of the interface between the first layer and the substrate, which is taken as the surface of the substrate. Furthermore, the direction perpendicular to this average line is set as the direction perpendicular to the substrate (the thickness direction of the coating layer). In addition, when the substrate has a curved surface, such as a drill bit, if the tool diameter is sufficiently large relative to the thickness of the coating layer, the interface between the coating layer and the substrate in the measurement area is approximately planar, and therefore the surface of the substrate can also be determined using the same method. That is, for example, in the case of a drill bit, element mapping using EDS is performed in the longitudinal section of the coating layer in a section perpendicular to the axial direction. By performing known image processing on the obtained element mapping, the interface between the coating layer and the substrate is determined. The roughness curve of the interface between the coating layer and the substrate thus obtained is averaged using an arithmetic method, and this averaged curve is taken as the surface of the substrate. Furthermore, the direction perpendicular to this averaged curve is set as the direction perpendicular to the substrate (the thickness direction of the coating layer).

[0144] Furthermore, the measurement area in the longitudinal section is set in a manner that includes all thickness regions of the coating layer. Considering the thickness of the coating layer, the accuracy of the thickness measurement, etc., it is preferable to perform observation and measurement in multiple fields of view (e.g., three fields of view) within a field of view of approximately 10 μm × 10 μm.

[0145] Furthermore, since the Si or W content varies repeatedly in the second layer, the surface layer (fourth layer), and the intermediate layer (fifth layer), the Si or W content in each layer is measured along multiple analytical lines (e.g., five lines) in a direction perpendicular to the substrate surface (the thickness direction of the coating layer). The locations where the Si and W contents are both 1 atomic percent (i.e., b = 0.01 or β = 0.01) are defined as the interfaces with adjacent layers. The thickness is calculated for each of the multiple lines, and the average of the calculated thicknesses is taken as the average thickness. Since the third layer is only one layer, the average thickness is taken as the average thickness of the thickness measured for this layer through multiple analytical lines.

[0146] The average content of the elements constituting each layer is obtained by averaging the results of line analysis in each layer.

[0147] 2. Confirmation of grains with NaCl-type face-centered cubic structure

[0148] By using electron beam diffraction with a transmission electron microscope (TEM), the crystal structures of the first layer, the second layer, the surface layer (fourth layer), and the intermediate layer (fifth layer) were identified, confirming that these crystal structures are NaCl-type face-centered cubic structures.

[0149] Example

[0150] The present invention will now be described with reference to specific embodiments, but the present invention is not limited to these embodiments.

[0151] <Example A>

[0152] The coating layer includes having Figure 1 The first, second, and third layers of the laminated body shown are described in an embodiment corresponding to an implementation of a covering tool having the covering layer (including an embodiment without a third layer and where the first layer is located on the outermost surface side of the laminated body).

[0153] The drill bit matrix was prepared as the base material.

[0154] Specifically, as raw material powders, Co powder, VC powder, TaC powder, NbC powder, Cr3C2 powder, and WC powder, each with an average particle size of 0.5–5 μm, were prepared. These raw material powders were combined as shown in Table 1, and wax was further added. The mixture was wet-mixed in a ball mill for 72 hours. After vacuum drying, it was pressed into shape at a pressure of 100 MPa. After sintering these pressed bodies, a sintered round bar for matrix forming with a diameter of 6 mm was formed. Next, drill bit substrates 1–3, with a diameter × length dimension of 6 mm × 48 mm and a helix angle of 30 degrees, made of WC-based cemented carbide, were further manufactured by grinding.

[0155] [Table 1]

[0156]

[0157] Next, film formation is performed as follows.

[0158] use Figures 6-7 The arc ion plating apparatus shown performs the following (1) to (5) processes sequentially on the drill bit substrates 1 to 3.

[0159] (1) With the drill bit substrate 1 to 3 ultrasonically cleaned in acetone and dried, it is installed along the outer periphery at a position radially away from the central axis of the rotating table in the arc ion plating apparatus.

[0160] (2) Exhaust air from the aforementioned device and maintain for 10 minutes. -2 While maintaining a vacuum below Pa, the aforementioned device is heated to 500°C using a heater, and then an Ar gas atmosphere of 0.2 Pa is set. A DC bias voltage of -200V is applied to the drill bit substrate rotating on the rotary table, thereby bombarding the surface of the drill bit substrate with argon ions for 20 minutes.

[0161] (3) In order to form the nitrogen atmosphere shown in Table 2, nitrogen gas is introduced into the aforementioned device as a reaction gas and maintained at a specified temperature. In addition, the rotary table is controlled at a specified speed, a specified DC bias voltage is applied to the drill bit substrate rotating on the rotary table, and a specified current is made to flow between the Al-Cr alloy target and the anode electrode to generate an arc discharge, thereby forming a first layer with a specified average thickness.

[0162] (4) As shown in Table 2, by generating an arc discharge by passing a specified current between the Al-Cr alloy target and the anode electrode, and by passing a specified current between the Al-Cr-Si alloy target and the anode electrode, an arc discharge is generated, thereby forming a second layer with a specified average thickness and repeated variations in Si content on the surface of the first layer formed in the manner described above.

[0163] (5) Repeat steps (3) and (4) to stack a predetermined number of first and second layers, and in a specific embodiment, form a third layer on the side closest to the tool surface to obtain Examples 1 to 6 shown in Table 4. Here, no third layer is formed in Examples 3 and 5.

[0164] Here, when the composition of the third layer differs from that of the first layer, it will be determined by... Figure 6 and Figure 7 The target shown in part number 9 is an Al-Cr alloy target for forming the third layer.

[0165] In the film-forming processes described in (1) to (5) above, by adjusting the arc current value, nitrogen partial pressure as a reaction gas, bias voltage, and film-forming temperature in the film-forming conditions of the first, second, and third layers, the full width at half maximum (FWHM) of the 111 diffraction lines of the NaCl-type face-centered cubic grains of the laminated layer simultaneously formed using Al-Cr alloy targets and Al-Cr-Si alloy targets is adjusted. 111 / I 200 The values ​​are controlled to specified values, and these values ​​are shown in Table 4.

[0166] Here, the X-ray diffraction results of Example 4 are presented. Figure 4 Regarding X-ray diffraction, Cu-Kα lines were used, and measurements were performed using the 2θ / θ focusing method, under the following conditions: measurement range (2θ): 30–80 degrees, scan step size: 0.015 degrees, and measurement time per step: 0.23 sec / step. Figure 4In the X-ray diffraction measurements, a 111 diffraction line, derived from the sum of the first, second, and third layers, was observed near 38 degrees, and a 200 diffraction line, also derived from the sum of the first, second, and third layers, was observed near 44 degrees. Furthermore, the peaks near 36 and 48 degrees are attributed to hexagonal WC crystals. The X-ray diffraction measurement conditions described in Example 4 are merely one example; other measurement conditions are possible as long as the aforementioned 111 and 200 diffraction lines can be confirmed.

[0167] On the other hand, for comparison purposes, for drill bit substrates 1-3, similarly to Examples 1-6, a film was formed of a laminate including a first layer and a second layer under the conditions shown in Table 3, and a third layer was formed in specific comparative examples, thereby producing the comparative example coated tools (referred to as "comparative examples") 1-6 shown in Table 5. Here, no third layer was formed in Comparative Examples 3 and 6.

[0168] Repeated variations in the average thickness, average composition, and Si content of each layer in the examples and comparative examples (Si max Si min The average interval between adjacent maxima and minima was determined using the aforementioned method. Furthermore, the presence of NaCl-type face-centered cubic grains in the first to third layers was also confirmed using the aforementioned method.

[0169] Furthermore, in neither the embodiments nor the comparative examples were found to have diffraction lines representing crystal structures other than the NaCl-type face-centered cubic structure, and there were no grains with crystal structures other than the NaCl-type face-centered cubic structure in an unavoidable amount.

[0170] Furthermore, the second layer in Comparative Example Tool 2 is formed from a single Al-Cr-Si alloy target, and compared to the embodiment, the absolute values ​​of the device temperature and bias voltage are larger, while the N2 gas pressure is lower. This creates an environment where it is difficult to form repeating variations in Si content, and no repeating structure of Si composition is formed in the second layer. That is, the Si content is approximately uniform along the thickness direction of the second layer, and no repeating variations in content are formed (see Table 5). In this respect, the layer structure of the second layer differs from that of the embodiment tool.

[0171]

[0172]

[0173]

[0174]

[0175] Next, the following cutting test 1 was conducted on Examples 1-6 and Comparative Examples 1-6 to evaluate the characteristics of the coating tool.

[0176] Cutting Test 1

[0177] Test content: Wet hole cutting test

[0178] Drill bit shape: Double-flute carbide drill bit with a cutting diameter of 6mm

[0179] Workpiece - Shape: Carbon steel S50C sheet

[0180] Cutting speed: 110 m / min.

[0181] Feed rate: 0.25mm / rev

[0182] Hole depth: 25mm (blind hole machining)

[0183] The evaluation of cutting test 1 is as follows, and the results are shown in Table 6.

[0184] That is, the number of holes drilled is measured until the wear on the flank face of the cutting edge reaches 0.3 mm, or until the tool tip reaches its lifespan due to chipping, breakage, or wear, and the wear condition of the tool tip is observed. When the number of holes drilled reaches 4000, the flank face wear of the coated tool that has not yet reached its lifespan is measured at the time of drilling 4000 holes.

[0185] [Table 6]

[0186]

[0187] (Note) ※ indicates the number of holes processed until the lifespan is reached due to chipping, damage, or breakage.

[0188] Regarding the aforementioned cutting test 1 (wet hole-making cutting test), during the machining of each hole, the tool tip continuously contacts the workpiece. When drilling the next hole after drilling one hole, the tool tip temporarily stops contacting the workpiece. Therefore, it can be said that the machining process includes both continuous and intermittent machining, resulting in high-load cutting.

[0189] As shown in Table 6, the tool of the embodiment exhibits less wear and a longer lifespan compared to the tool of the comparative example, with improved wear resistance and chipping resistance during high-load cutting. This embodiment uses a drill-shaped substrate, but the aforementioned effects can be achieved regardless of the substrate shape, as long as the same load is applied to the tool tip. For example, it can be said that when the insert is used on the substrate, the same improvement in cutting performance can be enjoyed in high-load cutting, including continuous and intermittent machining, such as machining of perforated or grooved round bars.

[0190] <Example B>

[0191] The coating layer includes having Figure 3The laminate of the first, second, third, surface (fourth) and intermediate (fifth) layers shown is described in connection with embodiments of a covering tool having the covering layers (including embodiments without the third and / or fifth layers).

[0192] Prepare the same drill bit substrate as in Example A (the drill bit substrate shown in Table 1). In addition, the film formation conditions for the first to third layers are the same as in Example A, as shown in Table 2.

[0193] After forming the first to third layers, as described below, the intermediate layer (fifth layer) is selectively formed, followed by the formation of the surface layer (fourth layer), resulting in Examples 11 to 24 as shown in Tables 11 and 12.

[0194] Here, in embodiments 17-24, only the first layer and the second layer, or only the first layer, the second layer and the third layer, are embodiments of the present invention.

[0195] The intermediate layer (fifth layer) is formed by the following method: According to the film formation conditions shown in Table 7, a specified current is flowed between the Al-Cr-Si alloy target and the anode electrode as described in Table 7 to generate an arc discharge, and simultaneously a specified current is flowed between the Ti-Si-W alloy target and the anode electrode as described in Table 7 to generate an arc discharge, thereby forming a film. Repeated variations in Si content are formed in this intermediate layer (fifth layer). For Examples 23 and 24, no intermediate layer is formed; instead, a surface layer (fourth layer) is formed directly above the first or third layer.

[0196] The surface layer (fourth layer) is formed by the following method: according to the film formation conditions shown in Table 8, an arc discharge is simultaneously generated between one or two Ti-Si-W alloy targets with different compositions as shown in Table 8 and the anode electrode, thereby forming the film. Repeated variations in W content are formed in this surface layer (fourth layer).

[0197] In the aforementioned film formation process, by adjusting the film formation conditions, the full width at half maximum (FWHM) and I of the combined 111 diffraction lines from the first, second, and third layers are obtained. 111 / I 200 The control is set to a specified value, which is shown in Table 11.

[0198] On the other hand, for comparison purposes, for drill bit substrates 1 to 3, the first to third layers (including cases where the first layer is present but not the third layer on the outermost surface of the laminate) were formed under the film-forming conditions shown in Table 3, similar to Comparative Examples 1 to 6, and film-forming of a coating layer having a surface layer (fourth layer) and an intermediate layer (fifth layer) was performed under the conditions shown in Tables 9 to 10, thereby producing Comparative Examples 12 to 16 shown in Tables 13 and 14.

[0199] Here, the X-ray diffraction results of Example 14 are presented. Figure 5 Besides Figure 4 In addition to the diffraction lines described, the 111 diffraction line of the surface layer (fourth layer) can be identified between 36 and 37 degrees, and the 200 diffraction line of the same layer can be identified between 42 and 43 degrees.

[0200] Furthermore, as described in Example A, the average thickness, average composition, repeating variations of Si content, and repeating variations of W content of each layer were determined using the aforementioned method. Additionally, the aforementioned method confirmed that the first to fifth layers contain NaCl-type face-centered cubic grains.

[0201] Regarding the surface layer (fourth layer) in Examples 20 and 14, the W content along the thickness direction of the surface layer (fourth layer) is approximately equal, and no repeated variation in W content is formed. The surface layer (fourth layer) of Examples 20 and 14, like the surface layers (fourth layers) of Examples 11, 12, 14, and 16, uses a Ti-Si-W alloy target for film formation. However, compared to these examples, the absolute values ​​of the device temperature and bias voltage are larger, and the N2 gas pressure is lower, thus creating an environment where repeated variation in W content is difficult to form, and no repeated variation in W content is formed.

[0202] [Table 7]

[0203]

[0204] [Table 8]

[0205]

[0206] (Note) "-" indicates that it is not used.

[0207] [Table 9]

[0208]

[0209] [Table 10]

[0210]

[0211] (Note) "-" indicates that it is not used.

[0212]

[0213]

[0214]

[0215]

[0216] Next, cutting tests 1 under the same conditions as in Example A were conducted on Examples 11-24 and Comparative Examples 12-16 to evaluate the characteristics of the coated tool. The results are shown in Table 15.

[0217] [Table 15]

[0218]

[0219] (Note) ※ indicates the number of holes processed until the lifespan is reached due to chipping, damage, or breakage.

[0220] As shown in Table 15, compared with the examples (Examples 2-6) which only have the first to third layers formed under the same film-forming conditions, the combination of the first to third layers and the fourth and fifth layers further improves the wear resistance and chipping resistance during high-load cutting. Furthermore, compared to Example 11, although the average thickness of the coating layer in Example 1 is greater (thicker) than that in Example 11, the flank wear of Example 11 is smaller, indicating that the combination of the fourth and fifth layers improves wear resistance.

[0221] Next, cutting tests 2, similar to those in Example A, were conducted on Examples 11-16 and Comparative Examples 12-16 to evaluate the characteristics of the coated tool. The results are shown in Table 16.

[0222] Cutting test 2

[0223] Test content: Wet hole cutting test

[0224] Drill bit shape: Double-flute carbide drill bit with a cutting diameter of 6mm

[0225] Workpiece - Shape: Carbon steel S50C sheet

[0226] Cutting speed: 125 m / min.

[0227] Feed rate: 0.25mm / rev

[0228] Hole depth: 30mm (through hole machining)

[0229] [Table 16]

[0230]

[0231] (Note) ※ indicates the number of holes processed until the lifespan is reached due to chipping, damage, or breakage.

[0232] The aforementioned cutting test 2 (wet hole-making test) is a high-load cutting test similar to cutting test 1 in Example A. However, since it involves through-hole machining with a higher cutting speed and more impacts, it can be considered a cutting test with a higher load than cutting test 1 in Example A. As shown in Table 16, the tool in Example B exhibits less wear and a longer lifespan compared to the comparative example tool. It also demonstrates higher wear resistance and chipping resistance in cutting tests with a higher load than cutting test 1 in Example A. Similar to Example A, Example B uses a drill bit base. However, as long as the same load is applied to the tool tip, the same effect can be achieved regardless of the shape of the base. For example, even when the insert is used on the base, the same effect can be enjoyed in high-load cutting, including continuous and intermittent machining, such as machining of perforated or grooved round bars.

[0233] The embodiments disclosed above are merely exemplary in all respects and are not restrictive. The scope of the invention is defined by the claims, not by the foregoing embodiments, and is intended to include all modifications in the same sense and scope as the claims.

[0234] Explanation of reference numerals in the attached figures

[0235] 1. Matrix

[0236] 2 First layer

[0237] 3 Second layer

[0238] 4. Third layer

[0239] 5. Surface layer (fourth layer)

[0240] 6. Intermediate layer (fifth layer)

[0241] 7-layer stack

[0242] 8 Anode Electrodes

[0243] 9. The fourth layer is formed using a Ti-Si-W alloy target (or the third layer is formed using an Al-Cr alloy target).

[0244] 10. Ti-Si-W alloy target for fourth layer formation

[0245] 11 Al-Cr-Si alloy targets for forming the second and fifth layers

[0246] 12. First layer formation using Ar-Cr alloy target

[0247] 13 Heaters

[0248] 14 Rotary Table

[0249] 15 Matrix

[0250] 16. Reaction gas inlet

[0251] 17 Exhaust port

[0252] 18 Arc Power Supply

[0253] 19 Bias Power Supply

Claims

1. A surface-coated cutting tool, comprising a substrate and a coating layer on the surface of the substrate, characterized in that, 1) The average thickness of the coating layer is 0.5 μm or more and 8.0 μm or less, and the coating layer has a laminated body consisting of one or more first layers and one or more second layers alternately stacked. 2) The layer closest to the substrate and the layer closest to the surface of the tool in the laminate are both the first layer. 3) The average thickness of the first layer is greater than 0.1 μm and less than 2.0 μm, and the first layer has (Al) 1-x Cr x The average composition of N, where 0.20 ≤ x ≤ 0.

60. 4) The average thickness of the second layer is greater than 0.1 μm and less than 2.0 μm, and the second layer has (Al) 1-a- b Cr a Si b The average composition of N, wherein 0.20≤a≤0.60, 0.01≤b≤0.20, the second layer has repeated variations in Si content with an average interval of more than 1 nm and less than 100 nm between adjacent maxima and minima, and the average value of the Si content maxima is Si. max 1.0 < Si max / b≤2.0, and the average value of the minimum Si content is Si min 0.0≤Si min / b<1.0, 5) Both the first and second layers have NaCl-type face-centered cubic grains. 6) When summarizing the X-ray diffraction peaks of the first and second layers, the full width at half maximum (FWHM) of the 111 diffraction peak is greater than 0.1 degrees and less than 1.0 degrees, and the intensity of the 111 diffraction peak is set to I. 111 Set the diffraction peak intensity of the 200 diffraction line to I. 200 At that time, I 111 / I 200 Greater than 1.0 and less than 5.

0.

2. The surface-coated cutting tool according to claim 1, characterized in that, A third layer is formed by replacing the first layer, which is closest to the surface of the tool, in the stacked body layers, the third layer having an average composition of (Al). 1-y Cr y N, where 0.20≤y≤0.60, the average thickness of the third layer is greater than 0.3μm and less than 4.0μm, and the average thickness of the third layer is greater than the average thickness of the other first layers of the laminate.

3. The surface-coated cutting tool according to claim 1, characterized in that, The first layer of the laminate, on the tool surface side closest to the tool surface, has a surface layer with an average thickness of 0.1 μm or more and 4.0 μm or less, and an average composition of (Ti) 1-α-β Si α W β N, where 0.01≤α≤0.20 and 0.01≤β≤0.

10. The surface layer has repeated variations in W content with an average interval of more than 1 nm and less than 100 nm between adjacent maxima and minima, and the average value of the maxima of the W content is W. max 1.0 < W max / β≤2.0, and the average value of the minimum value of the W content W min For 0.0≤W min / β<1.

0.

4. The surface-coated cutting tool according to claim 2, characterized in that, The third layer has a surface layer on the tool surface side, the surface layer having an average thickness of 0.1 μm or more and 4.0 μm or less, and the surface layer having an average composition of (Ti) 1-α-β Si α W β N, where 0.01≤α≤0.20 and 0.01≤β≤0.

10. The surface layer has repeated variations in W content with an average interval of more than 1 nm and less than 100 nm between adjacent maxima and minima, and the average value of the maxima of the W content is W. max 1.0 < W max / β≤2.0, and the average value of the minimum value of the W content W min For 0.0≤W min / β<1.

0.

5. The surface-coated cutting tool according to claim 3, characterized in that, An intermediate layer is provided between the first layer and the surface layer on the surface of the laminate closest to the tool, the intermediate layer having an average thickness of 0.1 μm or more and 2.0 μm or less, and the intermediate layer having an average composition of (Al). 1-k-l-m- n Ti k Cr l Si m W n N, where 0.20≤k≤0.65, 0.10≤l≤0.35, 0.00<m≤0.15, and 0.00<n≤0.

05. The intermediate layer has repeated variations in Si content with an average interval of more than 1 nm and less than 100 nm between adjacent maxima and minima, and the average value of the Si content maxima is Sim. max 1.0 < Sim max / m≤2.0, and the average value of the minimum value of the Si content Sim min =0.0≤Sim min / m<1.

0.

6. The surface-coated cutting tool according to claim 4, characterized in that, An intermediate layer is provided between the third layer and the surface layer, the intermediate layer having an average thickness of 0.1 μm or more and 2.0 μm or less, and the average composition of the intermediate layer being (Al). 1-k-l-m-n Ti k Cr l Si m W n N, where 0.20≤k≤0.65, 0.10≤l≤0.35, 0.00<m≤0.15, and 0.00<n≤0.

05. The intermediate layer has repeated variations in Si content with an average interval of more than 1 nm and less than 100 nm between adjacent maxima and minima, and the average value of the Si content maxima is Sim. max 1.0 < Sim max / m≤2.0, and the average value of the minimum value of the Si content Sim min =0.0≤Sim min / m<1.0.

Images