Hard coating and element covered with hard coating

Abstract

A hard coating (30; 50; 60; 70; 80; 90) to be applied to the surface of a substrate (12) in such a way as to cover the surface of the substrate (12), wherein the hard coating (30; 50; 60; 70; 80; 90) has a total thickness (Ttotal) in the range of 0.5 - 20 µm and comprises three types of layers (32, 38, 40; 34, 38, 42; 36, 40, 42) stacked alternately, wherein the three types of layers (32, 38, 40; 34, 38, 42; 36, 40, 42) consist of a single-composition layer (32; 34; 36) and two types of nanolayer alternating layers (38, 40; 38, 42; 40, 42) consist of the single composition layer (32; 34; 36) being formed by an A composition, a B composition and a C composition, and wherein the two types of nanolayer interlayers (38, 40; 38, 42;40, 42) nanolayers (32n, 34n, 36n) are contained, which are alternately layered on top of each other and which are formed by two of three combinations consisting of a combination of the A composition and the B composition, a combination of the A composition and the C composition and a combination of the B composition and the C composition, such that the nanolayers (32n, 34n; 32n, 36n) contained in one (38; 40) of the two types of nanolayer alternating layers (38, 40; 38, 42; 40, 42) are formed by one of the two of the three combinations and that the nanolayers (32n, 36n; 34n, 36n) contained in the other (40; 42) of the two types of nanolayer alternating layers (38, 40; 38, 42; 40, 42) are formed by one of the two of the three combinations 36n) are formed by the other of the two of the three combinations; the A composition is a nitride which is given by the composition formula AlaCrnSic&agr;is represented where the atomic ratios a, b, c, d satisfy 0.30 ≤ a ≤ 0.80, 0.15 ≤ b ≤ 0.65, 0 ≤ c ≤ 0.45, 0 ≤ d ≤ 0.10 and a + b + c + d = 1, where Si and α are optional additional components and where the optional additional component α at least one type of element is selected from B, C, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W; the B composition is a nitride represented by the composition formula CreBfSig&bgr;hre, where the atomic ratios e, f, g, h satisfy 0.40 ≤ e ≤ 0.95, 0.05 ≤ f ≤ 0.30, 0 ≤ g ≤ 0.45, 0 ≤ h ≤ 0.10 and e + f + g + h = 1, where Si and μ are optional additional components and where the optional additional component μ at least one type of element is selected from C, Al, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W; the C composition is a nitride defined by the composition formula AliCrj(SiC)k&ggr;l is represented, wherein the atomic ratios i, j, k, l satisfy 0.20 ≤ i ≤ 0.85, 0.10 ≤ j ≤ 0.50, 0.03 ≤ k ≤ 0.45, 0 ≤ l ≤ 0.10 and i + j + k + l = 1 and wherein the optional additional component ↑ is at least one type of element selected from B, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W; the single composition layer (32; 34; 36) has a thickness (T1) in a range of 0.5 - 1000 nm; and each of the nanolayers (32n, 34n, 36n) that form the two types of nanolayer interlayers (38, 40; 38, 42; 40, 42) has a thickness in the range of 0.5 - 500 nm and each of the two types of nanolayer interlayers (38, 40; 38, 42; 40, 42) has a thickness (T2, T3) in the range of 1 - 1000 nm.

Description

Technical field

[0001] The present invention relates to a hard coating and an element covered with a hard coating, and in particular to such a hard coating which has excellent wear resistance and weld resistance. State of the art

[0002] A hard coating is intended for various elements, such as different machining tools and friction parts that require wear resistance, to cover the surface of a substrate made of cemented carbide, high-speed tool steel, or the like. The various machining tools include cutting tools such as end mills, milling cutters, drills, lathe cutters, and cutting tips, as well as non-cutting tools such as thread formers and rotary tools. For example, patent document 1 proposes a hard coating with a multilayer structure of an AlCrN / AlTiSiN system. Patent document 2 proposes a hard coating with a multilayer structure of an AlCrN / CrN system. Patent document 3 proposes a hard coating with a multilayer structure of an AlCr / TiSi system.These hard coatings generally have excellent wear resistance and weld resistance. Objections to patent documents Patent document 1: JP 2012- 35 378 A Patent document 2: JP 2014- 79 834 A Patent document 3: JP 2008- 534 297 A Disclosure of the invention; Problem to be solved by the invention

[0003] However, it is possible that the hard coating described above may not provide sufficiently satisfactory performance, depending on factors such as machining and operating conditions, the type of workpiece material, and cutting speeds, leaving room for improvement. For example, if a cutting tool coated with a conventional hard coating is used for cutting titanium alloys, the tool may not have a sufficient service life due to early peeling or breakage of the hard coating, as titanium alloys have a relatively high degree of toughness.

[0004] The present invention was developed in light of the prior art discussed above. It is therefore an object of the invention to provide a hard coating and a tool covered with a hard coating that have excellent wear resistance and weld resistance and are capable of providing a certain service life even during cutting operations for, for example, cutting titanium alloys. Means of solving the problem

[0005] Various experiments and studies carried out in the situation described above by the inventor of the present invention and collaborators have revealed that a hard coating with high toughness and excellent durability can be obtained by using an A composition, a B composition, and a C composition, and layering them, for example, with certain thicknesses, wherein the A composition is a nitride of AlCrSiα, wherein Si and α are optional additional components, and wherein the optional additional component α is at least one type of element selected from B, C, Ti, V, Y, Zr, Nb, Mo, Hf, Ta, and W; and the B composition is a nitride of CrBSiß, wherein Si and β are optional additional components, and wherein the optional additional component β is at least one type of element selected from C, Al, Ti, V, Y, Zr, Nb, Mo, Hf, Ta, and W.and the C composition is a nitride of AlCr(SiC)γ, wherein the optional additional component γ is at least one type of element selected from B, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W. The present invention is based on the discovered fact.

[0006] A first invention relates to a hard coating that is to be applied to the surface of a substrate in such a way that it covers the surface of the substrate, characterized in that: (a) (a-3) the hard coating has a total thickness in the range of 0.5 - 20 µm and contains three types of layers that are stacked alternately on top of each other, wherein the three types of layers consist of (a-1) a single-composition layer and (a-2) two types of nanolayer alternating layers, wherein the single-composition layer is formed by an A-composition, a B-composition and a C-composition, and wherein the two types of nanolayer alternating layers contain nanolayers that are stacked alternately on top of each other and that are formed by two of three combinations consisting of a combination of the A-composition and the B-composition,(a) a combination of the A composition and the C composition and a combination of the B composition and the C composition, (b) the A composition is a nitride which is represented by the composition formula Al, a Cr b Si c a d is represented, wherein the atomic ratios a, b, c, d satisfy 0.30 ≤ a ≤ 0.80, 0.15 ≤ b ≤ 0.65, 0 ≤ c ≤ 0.45, 0 ≤ d ≤ 0.10 and a + b + c + d = 1, where Si and α are optional additional components and where the optional additional component α is at least one type of element selected from B, C, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W; (c) the B composition is a nitride represented by the composition formula Cr e B f Si g β his represented, wherein the atomic ratios e, f, g, h satisfy 0.40 ≤ e ≤ 0.95, 0.05 ≤ f ≤ 0.30, 0 ≤ g ≤ 0.45, 0 ≤ h ≤ 0.10 and e + f + g + h = 1, where Si and β are optional additional components and where the optional additional component β is at least one type of element selected from C, Al, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W; (d) the C composition is a nitride represented by the composition formula Al i Cr j (SiC) k Y Iis represented, wherein the atomic ratios i, j, k, I satisfy 0.20 ≤ i ≤ 0.85, 0.10 ≤ j ≤ 0.50, 0.03 ≤ k ≤ 0.45, 0 ≤ l ≤ 0.10 and i + j + k + l = 1, and wherein the optional additional component γ is at least one type of element selected from B, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W; (e) the single composition layer has a thickness in the range of 0.5 - 1000 nm; and (f) each of the nanolayers forming the two types of nanolayer interlayers has a thickness in the range of 0.5 - 500 nm, and each of the two types of nanolayer interlayers has a thickness in the range of 1 - 1000 nm.

[0007] It should be noted that the (SiC) in the carbon composition indicates that the (SiC) is present in the form of silicon carbide as a compound. Furthermore, it is difficult to precisely control the thickness of each layer across the entire range. Each thickness described in this description is an average value, and the actual thickness may deviate from a corresponding value within the ranges described above, as long as the average thickness falls within those ranges.

[0008] A second invention is characterized in the hard coating of the first invention by the fact that a ratio T1 / T2 the thickness T1 the individual composition layer to the thickness T2 of one of the two types of nanolayer alternating layers and a ratio T1 / T3 the thickness T1 the individual composition layer to the thickness T3The other of the two types of nanolayer interlayers both lie in a range of 0.2 - 10.

[0009] A third invention is characterized in the hard coating of the first or second invention in that a bottom layer of the single composition layer and the two types of nanolayer alternating layers, which are stacked alternately on top of each other, is arranged directly on a surface of the substrate.

[0010] A fourth invention is characterized in the hard coating of the first or second invention in that: (a) the hard coating includes an interface layer to be arranged between the hard coating and the substrate; (b), (c) the interface layer has a thickness in the range of 10–1000 nm and is provided by one of three types of layers, which are: (b-1) a single-composition layer formed by one of the A composition, one of the B composition, and one of the C composition; (b-2) an alternating nanolayer layer comprising two types of nanolayers, each formed by two of the A composition, one of the B composition, and one of the C composition, and which are alternately stacked such that each of the two types of nanolayers has a thickness of 0.5–500 nm;and (b-3) a layer of metal nitride, metal carbonitride or metal carbide formed by at least one type of element selected from B, Al, Ti, Y, Zr, Hf, V, Nb, Ta, Cr and W;

[0011] A fifth invention, in the case of a hard coating, is characterized by one of the first to fourth inventions in that: (a) the hard coating includes a surface layer that provides an outermost surface of the hard coating; (b) the surface layer is provided by a single-composition layer formed by one of the A composition, the B composition and the C composition, or by an alternating nanolayer layer containing two types of nanolayers, each formed by two of the A composition, the B composition and the C composition, and which are alternately stacked on top of each other such that each of the two types of nanolayers has a thickness in the range of 0.5 - 500 nm; and (c) the surface layer has a thickness of 5 - 1000 nm.

[0012] A sixth invention, in the case of a hard coating, is characterized by one of the first to fifth inventions in that: the coating hardness (HV0.025) of the hard coating is in a range of 2700 - 3300 (HV).

[0013] The coating hardness (HV0.025) is an HV value (Vickers hardness) of the hard coating, which is measured in accordance with the Vickers hardness test method (JIS G0202, Z2244) under a condition specified by the hardness symbol HV0.025.

[0014] A seventh invention is an element covered with a hard coating, comprising a substrate whose surface is partially or completely covered with a hard coating, and characterized in that the hard coating is the hard coating of one of the first to sixth inventions.

[0015] An eighth invention is characterized in the hard-coated element of the seventh invention in that the hard-coated element is an intermittently cutting tool having cutting edges and being rotated about an axis in such a way that it performs an intermittent cutting process through the cutting edges.

[0016] It is pointed out that, as long as a rounded value of an actual value lies within a corresponding numerical range defined in the inventions described above, such an actual value is to be interpreted as lying within the corresponding numerical range. Effects of the invention

[0017] In the hard coating of the present invention described above, the individual composition layer formed by the A composition has, depending on the proportions of Al and Cr, high hardness, oxidation resistance and toughness, and the individual composition layer formed by the B composition has, depending on the proportions of Cr and B, high toughness, lubricity and oxidation resistance.Furthermore, the single composition layer formed by the carbon composition exhibits low bonding affinity with oxygen, as silicon (Si) in the carbon composition is present in the form of silicon carbide (SiC). It also possesses a high degree of hardness, with minimal reduction in mechanical strength even at temperatures of 1000 °C or higher due to the covalent bond between the SiC and silicon. Consequently, the single composition layer formed by the carbon composition exhibits excellent heat resistance, wear resistance, and oxidation resistance. Each of the nanolayer interlayers possesses the properties described above, depending on the composition of the nanolayers. Additionally, each nanolayer interlayer has a thickness and smaller crystal particles than the single composition layer, resulting in high hardness and improved wear resistance.Furthermore, each of the nanolayer layers exhibits increased toughness thanks to its multilayer structure. The components α, β, and γ are optionally added to the respective A, B, and C compositions in a ratio of 10 at% (atomic percent) or less. This allows for the micronization of the coating's crystal particles and the control of particle size by adjusting the addition quantity. This, in turn, enables the adjustment of properties such as the coating's hardness, oxidation resistance, toughness, and lubricity. The structure, in which one type of single-composition layer and the two types of nanolayer layers with the properties described above are stacked alternately at predetermined thicknesses, makes it possible to achieve a hard coating with excellent wear resistance, lubricity, weld resistance, and toughness.Thanks to these features, in the case of a cutting tool, for example, it has become possible to increase the tool's service life thanks to its high toughness, which suppresses breakage and peeling of the hard coating, during cutting operations with various workpiece materials such as carbon steel, stainless steel, cast iron, alloy steel and titanium alloy, or under harsh machining conditions such as high-speed machining and dry machining.

[0018] Since the ratio in the second invention T1 / T2 the thickness T1 the individual composition layer to the thickness T2 of one of the two types of nanolayer alternating layers and the ratio T1 / T3 the thickness T1 the individual composition layer to the thickness T3The other of the two types of nanolayer interlayers, both of which are in a range of 0.2 - 10, are provided with corresponding thicknesses, one type of single composition layer and the two types of nanolayer interlayers, which ensure certain properties, making it possible to achieve corresponding performance characteristics such as wear resistance and weld resistance.

[0019] In the third invention, the lowest layer of the three types of layers, which consist of one type of single-composition layer and two types of nanolayer alternating layers that are stacked alternately on top of each other, is arranged directly on a surface of the substrate, so that the coating formation costs can be reduced compared to an arrangement in which an interface layer or the like is provided in a boundary adjacent to the substrate.

[0020] In the fourth invention, the interface layer is provided in the boundary adjacent to the substrate, which is formed by the predetermined composition or compositions and which has the predetermined thickness, so that it is possible to increase the adhesion strength of the hard coating to the substrate.

[0021] In the fifth invention, the outermost layer of the hard coating is the surface layer, which is formed by the predetermined composition or compositions and has the predetermined thickness, so that it is possible to improve certain coating performances such as wear resistance and weld resistance by appropriately determining the composition or compositions and the thickness of the surface layer.

[0022] In the sixth invention, the coating hardness (HV0.025) of the hard coating is in the range of 2700 - 3300 (HV), so that wear resistance and high toughness can be achieved with an excellent balance between them, thereby suppressing breakage and peeling of the hard coating and accordingly achieving excellent durability.

[0023] In the case of the seventh invention, which relates to the element covered with a hard coating, it is possible, since the hard coating is provided by each of the first to sixth inventions, to achieve essentially the same effects as the corresponding invention.

[0024] In the eighth invention, the element covered with a hard coating is an intermittent cutting tool, such as an end mill or a cutter, such that the element covered with the hard coating is repeatedly subjected to an impact load and is slightly heated when a cutting process occurs intermittently through the cutting edges. Therefore, the hard coating of the present invention, which is capable of achieving high wear resistance, toughness, lubricity, and weld resistance, is advantageously used for such an intermittently cutting tool. List of characters Fig. Figure 1 is a front view showing an exemplary end mill in which the present invention is used. Fig. Figure 2 is an enlarged bottom view from the side of a far end of the end mill. Fig. 1 seen. Fig. Figure 3 is a schematic view illustrating the coating structure of a hard coating applied to the end mill of Fig. 1 is planned. Fig. Figure 4 is a schematic view illustrating another example of the coating structure of the hard coating applied to the end mill of Fig. 1 is planned. Fig. Figure 5 is a schematic view illustrating yet another example of the coating structure of the hard coating applied to the end mill of Fig. 1 is planned. Fig. Figure 6 is a schematic view illustrating yet another example of the coating structure of the hard coating applied to the end mill of Fig. 1 is planned. Fig. Figure 7 is a schematic view illustrating yet another example of the coating structure of the hard coating applied to the end mill of Fig. 1 is planned. Fig. Figure 8 is a schematic view illustrating yet another example of the coating structure of the hard coating applied to the end mill of Fig. 1 is planned. Fig. Figure 9 is a schematic view to illustrate an arc ion plating device as an example of a physical vapor deposition device for forming the hard coating of each of the Fig. 3 - Fig. 8 on a tool substrate. Fig. Figure 10 is a view showing the types of constituent elements and their proportions in an A composition that forms the hard coating of each test specimen 1 - 50 used in a cutting test. Fig. Figure 11 is a view showing types of constituent elements and their proportions in a B composition that forms the hard coating of each test specimen 1 - 50. Fig. Figure 12 is a view showing the types of constituent elements and their proportions in a C composition that forms the hard coating of each test sample 1 - 50. Fig. Figure 13 is a view showing the coating structure of the hard coating of each test sample 1 - 25. Fig. Figure 14 is a view showing the coating structure of the hard coating of each test sample 26 - 50. Fig. Figure 15 is a view showing a coating hardness of the hard coating of each test sample 1 - 50 as well as a wear width, a cutting distance and an assessment result that were measured or achieved during the cutting test. Types of embodiments of the invention

[0025] The present invention is advantageously used for a hard coating applied to the surface of one of several machining tools, including rotating cutting tools such as end mills, milling cutters, taps, and drills; non-rotating cutting tools such as lathe cutters; and non-cutting tools such as thread formers, rotary tools, and press tools. However, the present invention can also be used for a hard coating that serves as a surface protection coating for a bearing element, a semiconductor device, or the like, specifically as a hard coating applied to an element other than the machining tools and which must, for example, possess wear resistance, lubricity, and oxidation resistance.Furthermore, the present invention is also applicable to a cutting tip that can be attached to one of several machining tools. Advantageously, cemented carbide, high-speed tool steel, cermet, ceramic, polycrystalline diamond (PCD), monocrystalline diamond, polycrystalline CBN, or monocrystalline CBN are used as the tool substrate of a tool covered with a hard coating, although other tool materials can also be used. Advantageously, a PVD (physical vapor deposition) process such as arc ion plating, sputtering, and PLD (laser beam evaporation) is used as a method for forming the hard coating.

[0026] The hard coating of the present invention is advantageously used for a cutting tool that performs a cutting operation for cutting, for example, titanium alloy, but it can also advantageously be used for a cutting tool that performs a cutting operation for cutting other workpiece materials such as carbon steel, stainless steel, cast iron and alloy steel, since it has excellent wear resistance, lubricity, weld resistance and toughness.

[0027] The hard coating contains three types of layers stacked alternately. These three types of layers consist of a single-composition layer and two types of nanolayer alternating layers. The single-composition layer is formed by an A composition, a B composition, and a C composition. The two types of nanolayer alternating layers contain nanolayers stacked alternately and are formed by two of three combinations: a combination of A and B composition, a combination of A and C composition, and a combination of B and C composition. The stacking sequence of the layers is determined accordingly.It is preferable that the three types of layers, consisting of the single-composition layer and the two types of nanolayer alternating layers, be stacked on top of each other in the predetermined sequence for at least one cycle, and that the three types of layers are stacked on top of each other for one complete cycle or cycles such that the number of each of the three types of layers is equal. However, the stacking of the three types of layers can be terminated without any top layer of the three types of layers completing a corresponding cycle, for example, such that the top layer is the same type as a bottom layer of the three types of layers. This also applies to the types of nanolayer alternating layers, each of which contains the nanolayers of the two compositions stacked alternately on top of each other.It is preferable that the two types of nanolayers are stacked on top of each other for at least one cycle. However, the number of nanolayers stacked on top of each other in each of the two types of nanolayer interlayers can be an odd number. If the hard coating contains an interface layer and / or a surface layer, the total thickness of the hard coating includes the thickness of the interface layer and / or the thickness of the surface layer.

[0028] It is preferable that a relationship T1 / T2 the thickness T1 the individual composition layer to the thickness T2 of one of the two types of nanolayer alternating layers and a ratio T1 / T3 the thickness T1 the individual composition layer to the thickness T3 The other of the two types of nanolayer interlayers both lie in a range of 0.2–10. However, each of the thicknesses can T1 , T2 , T3The value is set to a level by which the corresponding ratio deviates from the corresponding numerical range. The hard coating may, if required, include an interface layer to be provided between the hard coating and the substrate. It is preferable that the interface layer be formed by a single-composition layer consisting of one A, one B, and one C component, or by an alternating nanolayer layer containing two types of nanolayers, each consisting of two A, one B, and one C component, arranged alternately.However, the interfacial layer can be a layer of metal nitride, metal carbonitride, or metal carbide formed by at least one type of element composed of B, Al, Ti, Y, Zr, Hf, V, Nb, Ta, Cr, and W, or a layer formed by another composition or compositions. The interfacial layer has a thickness preferably in the range of 5–1000 nm. However, the thickness of the interfacial layer can be outside the numerical range of 5–1000 nm.

[0029] The hard coating may, if required, have a surface layer. It is preferable that the surface layer be formed by a single-composition layer consisting of one of the A, one of the B, and one of the C components, or by an alternating nanolayer layer containing two types of nanolayers, each consisting of two of the A, B, and C components, respectively, stacked alternately. However, the surface layer may be a layer consisting of a different composition or compositions. The surface layer has a thickness preferably in the range of 0.5–1000 nm. However, the thickness of the surface layer may be outside this range.

[0030] Regarding the coating hardness (HV0.025) of the hard coating, insufficient wear resistance could be achieved if it were too low, and the hard coating could easily peel or break if it were excessively high. Therefore, regardless of the presence or absence of the interface and surface layers, it is appropriate for the coating hardness to be in a range of, for example, approximately 2700–3300 (HV), and it is preferable for the coating hardness to be in a range of, for example, approximately 2800–3200 (HV). However, the coating hardness (HV0.025) of the hard coating may be less than 2700 (HV) or greater than 3300 (HV), depending on, for example, the type of workpiece material and the machining and operating conditions.

[0031] According to the findings obtained by the inventor of the present invention and his collaborators, the hard coating of the present invention, thanks to the alternating layering of the three types of layers—consisting of one type of single-composition layer and two types of alternating nanolayer layers—exhibits superior mechanical properties (hardness), wear resistance, oxidation resistance, and shear strength compared to a multilayer coating based on ALCrN or ALCrTiN. Furthermore, high hardness can be achieved due to the inhibition of lattice dislocations, which is facilitated by an interface between each pair of adjacent layers exhibiting different elastic properties (modulus of elasticity and hardness). This interface not only contributes to increased coating hardness but also improves toughness by inhibiting energy dissipation and crack propagation.Since the interface strongly influences the properties of the multilayer coating, the provision of the nanolayer layering, in which a layering cycle of the nanolayers lies in the nanometer range, makes it possible to achieve the effects of an improvement in the mechanical properties and the tribology of the hard coating when the sizes of the crystal particles and the coating density are adjusted accordingly by controlling the thickness of each nanolayer of the nanolayer layering.

[0032] Furthermore, each of the individual layers of nano-, interface, and nanolayer alternating layers exhibits better wear resistance and toughness than a conventional multilayer coating of coarse particles, thanks to the diffusion of a mixture of amorphous alloy phase and crystalline phase. Within each of the nanolayer alternating layers, the internal stress is reduced due to particle boundary dislocation and disclination, thereby suppressing cracks and fractures in the coating during machining, such as intermittent cutting.

[0033] The hard coating of the present invention, thanks to the formation of fine particles, has a smooth surface and a dense surface structure, and consequently, improved wear resistance. Furthermore, numerous boundaries are defined by the interfaces, which, through particle boundary dislocation and disclination, weakens the internal stress across these interfaces. This results in improved toughness and hardness, making it possible to suppress the propagation of cracks and fractures in the coating during machining, such as intermittent cutting processes. Example of implementation

[0034] In the following, an embodiment of the invention is described in detail with reference to the drawings.

[0035] Fig. 1 is a front view showing a milling cutter 10shows an example of an element covered with a hard coating in which the present invention is used. Fig. Figure 2 is an enlarged bottom view from the side of a far end of the end mill. 10 seen. The end mill. 10 is mainly determined by a tool substrate 12 (see Fig. 3 - Fig. 8) formed from hard metal, and the tool substrate 12 The end mill comprises a shank section 14 and a cutting edge section 16, which together form a single unit. The cutting edge section 16 is provided with five cutting edges arranged at equal intervals around an axis of the end mill. 10 are provided around, with each of the cutting edges being a peripheral cutting edge 18 and an end cutting edge 20 exhibits this. If the end mill 10 As the end mill rotates around the axis, it guides the end mill. 10 through the peripheral cutting edge 18and the final cutting edge 20 The cutting edge undergoes an intermittent cutting process. In this embodiment, the end mill is... 10 a radius cutter in which the peripheral cutting edge 18 and the final cutting edge 20 They are joined together at a rounded corner. The end mill 10 is a tool covered with a hard coating and corresponds to an intermittently cutting tool.

[0036] One in Fig. 3 shown hard coatings 30 is designed to cover a surface of the blade section 16, which is a section of the tool substrate 12 is. Fig. Figure 3 is a schematic view, magnified to show a cross-section of a neighborhood of the surface of the hard coating 30 The covered blade section is 16. The area of ​​the surface covered by the hard coating 30 is covered, is in Fig. 1 is represented by a hatched area. It is also possible to apply the hard coating. 30 to be provided in such a way that the entirety of the ball head milling cutter 10 including the shaft section 14 with the hard coating 30 is covered.

[0037] The hard coating 30 It has a multi-layered structure and contains an A-layer. 32 , a nanolayer alternating layer 38 and a nanolayer interlayer 40 , which in this order of description in one direction from an outer surface of the hard coating 30 to the tool substrate 12 are arranged there. The A-position 32 , the nanolayer alternating layer 38 and the nanolayer alternating layer 40 are layered on top of each other for at least one cycle. The hard coating 30 also includes a boundary surface location 44 , which in their attachment to the tool substrate 12adjacent boundary section is provided. This means that on a surface of the tool substrate 12 first, the boundary situation 44 is arranged and then on the boundary surface 44 the nanolayer alternating layer 40 , the nanolayer alternating layer 38 and the prime location 32 are arranged. The nanolayer alternating layer 40 , the nanolayer alternating layer 38 and the A-layer 32 are repeatedly layered on top of each other in this order of description, such that a top section of the hard coating 30 due to the A-location 32 is provided. The hard coating 30 with the border area 44 has a total thickness Ttotal , which is accordingly set to a value in the range of 0.5 - 20 µm. The A-layer 32 has a thickness T1, which is accordingly set to a value in the range of 0.5 - 1000 nm. The nanolayer alternating layers 38 , 40 each have thicknesses T2 , T3 , each of which is set to a value in the range of 1–1000 nm. Furthermore, the thicknesses are T1 - T3 adjusted to the respective values ​​in such a way that a ratio T1 / T2 the thickness T1 to the thickness T2 and a relationship T1 / T3 the thickness T1 to the thickness T3 Both are in a range of 0.2 - 10.

[0038] The prime location 32 is a single compound layer formed solely by an A compound. The A compound is a nitride with the formula Al a Cr b Si c a dis represented where the atomic ratios a, b, c, d satisfy 0.30 ≤ a ≤ 0.80, 0.15 ≤ b ≤ 0.65, 0 ≤ c ≤ 0.45, 0 ≤ d ≤ 0.10 and a + b + c + d = 1, where Si and α are optional additional components and where the optional additional component α is at least one type of element selected from B, C, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W. Fig. Figure 10 is a view showing examples of the content (at%) of each element in the A composition, where each blank space indicates that the content (at%) of the corresponding element is 0, and each gray area (each column with scatter dots) indicates that the atomic ratio corresponding to the content of the respective element deviates from the corresponding numerical range of the composition formula described above. This means that test samples 7-50 meet the requirements of the A composition. The A layer 32With this composition, a crystal system in the form of a cubic rock salt structure is characterized by high hardness and excellent wear resistance. Depending on the ratios of Al and Cr, it provides high hardness, oxidation resistance, and toughness. Furthermore, the addition of the optional component Si in a predetermined ratio increases heat resistance. Additionally, the addition of the optional component α in a ratio of no more than 10 at% allows for micronization of the crystal particles and control of particle size by adjusting the addition quantity, thereby adjusting the hardness, toughness, and lubricity of the coating. The presence of this component in the A-layer also improves 32The elements contained in the material enhance lubricity and oxidation resistance, improving strength and toughness at high temperatures during heat-generating cutting processes. These properties help suppress chipping and fractures under cutting conditions involving high impacts and mechanical loads. Furthermore, oxidation wear caused by heat generated during high-speed machining or similar operations is reduced, and an excellent balance between wear and weld resistance is achieved, resulting in high durability even during high-speed and dry machining.

[0039] The nanolayer alternating layer 38 has a multilayered structure that includes an A-nanolayer 32n and a B-nanolayer 34ncontains layers that are alternately stacked on top of each other for at least one cycle, with the A-nanolayer 32n like the A-location 32 formed by the A composition and the B nanolayer 34n is formed by the B composition. In this embodiment, a bottom section of the nanolayer interlayer is formed. 38 through the A-nanolayer 32n provided, while a top section of the nanolayer interlayer 38 through the B-nanolayer 34n is provided. However, the bottom section and the top section of the nanolayer interlayer can 38 each through the B-nanolayer 34n and the A-nanolayer 32n be provided. The A-nanolayer 32n and the B nanolayer 34nEach has a thickness that is adjusted to a value within the range of 0.5–500 nm. The B composition is a nitride with the formula Cr e B f Si g β h is represented where the atomic ratios e, f, g, h satisfy 0.40 ≤ e ≤ 0.95, 0.05 ≤ f ≤ 0.30, 0 ≤ g ≤ 0.45, 0 ≤ h ≤ 0.10 and e + f + g + h = 1, where Si and β are optional additional components and where the optional additional component β is at least one type of element selected from C, Al, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W. Fig. Figure 11 shows examples of the content (at%) of each element in the B composition, where each blank space indicates that the content (at%) of the corresponding element is 0, and each gray area (each column with scatter dots) indicates that the atomic ratio corresponding to the content of the respective element deviates from the corresponding numerical range of the composition formula described above. This means that test samples 7-50 meet the requirements of the B composition. Depending on the proportions of Cr and B, the B composition provides high toughness, lubricity, and oxidation resistance, albeit with relatively low hardness. Furthermore, by adding the optional additional component Si in a predetermined ratio, it is possible to improve high-temperature strength, heat resistance, lubricity, and oxidation resistance.The addition of the optional component β in a ratio of no more than 10 at% gives the coating high hardness and excellent oxidation resistance, resulting in improved wear resistance. The B composition has a cubic crystal structure, and the crystal particles are micronized by the addition of the optional component β, further improving hardness and wear resistance. The crystal structure is oriented with higher priority towards the (200) face than the (111) face, and the integral strength of a diffraction line on the (200) face is 1.5 times or more greater than that on the (111) face.

[0040] The nanolayer alternating layer 40 has a multilayered structure that includes the A-nanolayer 32n and a carbon nanolayer 36n contains, which are stacked on top of each other for at least one cycle, with the A-nanolayer 32nlike the A-location 32 formed by the A composition and the C nanolayer 36n is formed by the C composition. In this embodiment, a bottom section of the nanolayer interlayer is used. 40 through the A-nanolayer 32n provided, while a top section of the nanolayer interlayer 40 through the C-nanolayer 36n is provided. However, the bottom section and the top section of the nanolayer interlayer can 40 each through the C-nanolayer 36n and the A-nanolayer 32n be provided. The A-nanolayer 32n and the carbon nanolayer 36n Each has a thickness that is adjusted to a value within the range of 0.5–500 nm. The carbon composition is a nitride with the formula Al i Cr j (SiC) k Y Iis represented where the atomic ratios i, j, k, l satisfy 0.20 ≤ i ≤ 0.85, 0.10 ≤ j ≤ 0.50, 0.03 ≤ k ≤ 0.45, 0 ≤ I ≤ 0.10 and i + j + k + l = 1 and where the optional additional component γ is at least one type of element selected from B, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W. Fig. Figure 12 shows examples of the content (at%) of each element in the carbon composition, where each blank space indicates that the content (at%) of the corresponding element is 0, and each gray area (each column with scatter dots) indicates that the atomic ratio corresponding to the content of the respective element deviates from the corresponding numerical range of the composition formula described above. This means that test samples 7-50 meet the requirements for the carbon composition. The carbon composition has low bonding affinity with oxygen because Si is present in the carbon composition in the form of SiC (silicon carbide) as a compound, and the SiC is a covalent bond. Therefore, the hardness is high, with only a slight reduction in mechanical strength even at temperatures of 1000°C or higher, and high lubricity is ensured.The C composition is thus characterized by high hardness as well as excellent heat resistance, oxidation resistance, and wear resistance. Furthermore, by adding the optional additional component γ in a ratio of no more than 10 at%, it is possible to micronize the crystal particles and control the particle size by adjusting the addition quantity, thereby adjusting the coating's hardness, toughness, and lubricity. Thanks to its excellent wear and oxidation resistance, it is possible to reduce oxidative wear caused by heat generated during high-speed machining or similar processes and to achieve sufficient wear and weld resistance, thus ensuring high durability even under high-speed and dry machining conditions.

[0041] Each of the nanolayer alternating layers 38, 40 depending on the composition of the nanolayers 32n , 34n , 36n for the properties described above and is characterized by high hardness as well as excellent wear resistance, toughness and oxidation resistance. Specifically, the interface between the nanolayers bears the load. 32n , 34n , 36n This contributes to an increase in coating hardness and, thanks to its ability to inhibit energy dissipation and crack propagation, also to an improvement in toughness. Since the nanolayer build-up cycle 32n , 34n , 36n Since the dimensions are in the nanometer range, it is also possible to achieve improvements in the mechanical properties and tribology of the hard coating by adjusting the crystal particle sizes and coating density accordingly, specifically by varying the thickness of each nanolayer. 32n , 34n ,36n is controlled. Each of the nanolayer alternating layers 38 , 40 Thanks to a mixture diffusion of amorphous alloy phase and crystalline phase, it has better wear resistance and toughness than a conventional multilayer coating of coarse particles. In each of the nanolayer alternating layers 38 , 40 The internal stress is reduced thanks to particle boundary dislocation and disclination, thereby suppressing cracks and fractures in the coating and their propagation during processing, such as intermittent cutting. The nanolayer alternating layer 38 It has excellent oxidation resistance and lubricity, and a hardness (measured by nanoindentation) of approximately 38–40 GPa. The nanolayer interlayer 40 It has a high hardness, and the hardness (measured by nanoindentation) is approximately 43 - 45 GPa.

[0042] Since the A-location 32and the two types of nanolayer interlayers 38 , 40 Furthermore, by layering the layers alternately, the internal tension can be balanced by varying the hardness of each layer. 32 , 38 , 40 The adhesive strength between the layers is adjusted accordingly. 32 , 38 , 40 increased, so that peeling is suppressed and excellent chipping and wear resistance is achieved even during high-speed machining of materials of high hardness or other difficult-to-cut materials.

[0043] The border area situation 44 is a single-composition site, similar to the A-site 32 is formed solely by the A composition. The boundary surface position 44 It has a thickness that is set to a value in the range of 5–1000 nm. Since the interface position44 in a way that is attached to the tool substrate 12 If the adjacent boundary is provided, the adhesion strength of the hard coating can be increased. 30 on the tool substrate 12 will be increased.

[0044] Regarding the coating hardness (HV0.025) of the hard coating 30 Sufficient wear resistance could not be achieved if it were low, and the hard coating 30 It could easily peel off or break if its hardness were excessively high. In the exemplary embodiment, the coating hardness is in the range of approximately 2700–3300 (HV).

[0045] The Fig. 4 - Fig. Figure 8 shows further examples of the hard coatings, each of which is on the surface of the blade section 16 of the end mill. 10 to be ordered. Each of the Fig. 4 - Fig. 8 is a schematic sectional view, which corresponds to the view of Fig. 3 corresponds to, and the total thickness Ttotal The thickness of any hard coating lies in the range of 0.5 - 20 µm. A hard coating 50 from Fig. 4 differs from the hard coating described above. 30 insofar as instead of the A-position 32 a B-position 34 It is planned that instead of the nanolayer alternating layer 40 a nanolayer alternating layer 42 is planned and that instead of the border area location 44 a border area location 52 is intended. In the hard coating 50 from Fig. 4 has the B position 34 a thickness T1 , which is accordingly set to a value in the range of 0.5 - 1000 nm. The nanolayer alternating layers 38 , 42 each have thicknesses T2 , T3 , each of which is set to a value in the range of 1–1000 nm. Furthermore, the thicknesses are T1 - T3adjusted to the respective values ​​in such a way that a ratio T1 / T2 the thickness T1 to the thickness T2 and a relationship T1 / T3 the thickness T1 to the thickness T3 Both are in a range of 0.2–10. It should be noted that the thickness T1 the B-position 34 regardless of thickness T1 the A-position described above 32 The layers are determined. 32 , 34 but both individual composition layers have numerical ranges that are equal to each other, so that the same reference symbol “T1” can be used as a common reference symbol for the thicknesses of the A-layer 32 and B-position 34 is used. The same applies to the thicknesses. T2 , T3 the nanolayer alternating layers 38 , 42 .

[0046] The B-position 34is a single composition layer formed solely by the B composition. The nanolayer alternating layer 42 has a multilayered structure that includes the B nanolayer 34n and the carbon nanolayer 36n It contains nanolayers that are alternately layered on top of each other for at least one cycle. In this embodiment, a bottom section of the nanolayer alternating layer is used. 42 through the B-nanolayer 34n provided, while a top section of the nanolayer interlayer 42 through the C-nanolayer 36n is provided. However, the bottom section and the top section of the nanolayer interlayer can 42 also through the C-nanolayer 36n and the B nanolayer 34n be provided. The B-nanolayer 34n and the carbon nanolayer 36nEach has a thickness, each of which is set to a value within a range of 0.5–500 nm. The interface position 52 is a single-composition layer formed solely by the B composition, and its thickness is adjusted to a value within the range of 5–1000 nm. The nanolayer interlayer 42 It has excellent oxidation resistance and lubricity and a hardness (hardness measured by nanoindentation) of about 38 - 40 GPa.

[0047] A hard coating 60 from Fig. 5 differs from the hard coating described above. 30 insofar as instead of the A-position 32 a C-position 36 It is planned that instead of the nanolayer alternating layer 38 the nanolayer alternating layer 42 is planned and that instead of the border area location 44 a border area location 62is intended. In the hard coating 60 from Fig. 5 has the C position 36 a thickness T1 , which is accordingly set to a value in the range of 0.5 - 1000 nm. The nanolayer alternating layers 40 , 42 each have thicknesses T2 , T3 , each of which is set to a value in the range of 1–1000 nm. Furthermore, the thicknesses are T1 - T3 adjusted to the respective values ​​in such a way that a ratio T1 / T2 the thickness T1 to the thickness T2 and a relationship T1 / T3 the thickness T1 to the thickness T3 Both lie within a range of 0.2–10. The C-position 36 is a single-composition layer formed solely by the C composition. The interface layer 62 is a nanolayer interlayer with two types of A-nanolayer 32n , B-nanolayer 34n and carbon nanolayer36n , which are layered alternately on top of each other, and a thickness that is adjusted accordingly to a value in the range of 5–1000 nm. Each of the two types of nanolayers, the two types of A-nanolayer 32n , B-nanolayer 34n and carbon nanolayer 36n are, has a thickness that is set accordingly to a value in the range of 0.5 - 500 nm.

[0048] A hard coating 70 from Fig. 6 differs from the hard coating described above. 30 regarding the stacking sequence of the A-layer 32 and the nanolayer alternating layers 38 , 40 In the hard coating 70 is the A-location 32 between the nanolayer alternating layer 40 and the nanolayer alternating layer 38 arranged and the nanolayer alternating layer 40 is considered the outermost layer of the hard coating 70planned. Furthermore, instead of the boundary surface location 44 , which is formed by the A composition, the boundary position 62 The planned material is a nanolayer alternating layer. It is noted that the layering sequence of the three types of layers 32 , 38 , 40 , which are stacked alternately on top of each other, can be determined accordingly, for example in such a way that the A-layer 32 between the nanolayer alternating layer 38 and the nanolayer alternating layer 40 is arranged, whereby the nanolayer alternating layer 38 as the outermost layer. The same applies to the other hard coatings. 50 , 60 Furthermore, a combination of one type of A-position is possible. 32 , B-position 34 and C-position 36 and the two types of nanolayer interlayers 38 , 40 , 42be determined, for example, in such a way that the A-position 32 and the nanolayer alternating layers 38 , 42 are stacked on top of each other, or in such a way that the A-layer 32 and the nanolayer alternating layers 40 , 42 are stacked on top of each other.

[0049] A hard coating 80 from Fig. 7 differs from the hard coating described above. 30 insofar as the boundary situation 44 missing.

[0050] A hard coating 90 from Fig. 8 differs from the hard coating described above. 30 insofar as a surface layer 92 for the outermost surface of the hard coating 90 ensures and that a border area location 94is formed by a composition or compositions that are different from the A, B, and C compositions. The surface layer 92 is provided by a single-layer composition, which is similar to the A-layer. 32 , B-position 34 or C-position 36 formed by a composition of A, B and C, or it is like the boundary situation described above. 62 a nanolayer alternating layer that contains two types of A-nanolayer 32n , B-nanolayer 34n and carbon nanolayer 36n It contains nanolayers that are layered alternately such that each of the two types of nanolayers has a thickness in the range of 0.5–500 nm. The surface layer 92 It has a thickness that is set to a value in the range of 0.5–1000 nm. The interface position 94is formed by a metal nitride, metal carbonitride or metal carbide formed by at least one type of element selected from B, Al, Ti, Y, Zr, Hf, V, Nb, Ta, Cr and W, and it has a thickness appropriately set to a value in the range of 5 - 1000 nm.

[0051] Furthermore, the hard coating can be structured in other ways, even if this is not shown in the drawings. For example, in each of the hard coatings 30 , 50 , 60 , 70 , 80 , 90 the three types of sites that consist of the one type of single-composition site (which is formed by a site different from the A-site) 32 , B-position 34 and C-position 36 is provided) and two of the nanolayer alternating layers 38 , 40 , 42The layers consist of three types of layers stacked alternately in a predetermined sequence for a complete cycle or cycles, such that the number of each type is equal. However, the stacking of the three types of layers can be terminated without either the topmost or bottommost layer completing a corresponding cycle, for example, by removing the A-layer. 32 , which are for the top layer of the hard coating 30 This ensures that it is omitted. In other words, it can also be omitted in any of the hard coatings. 30 , 50 , 60 , 70 , 80 , in which the surface layer is not provided, the outermost layer is considered a surface layer that is different from the three types of layers that are alternately stacked on top of each other. Also, what each of the nanolayer alternating layers 38 , 40 , 42concerns which contains the two types of nanolayers (each containing two from the A-layer). 32n , B-nanolayer 34n and carbon nanolayer 36n (are), which are stacked alternately on top of each other, the number of stacked nanolayers can also be an odd number, for example such that the nanolayer alternating layer 38 with the A-nanolayer 32n begins and with the A-nanolayer 32n ends. Furthermore, it is possible to use either of the boundary layer positions instead. 44 , 52 , 62 , 94 to use a boundary layer that is a single composition layer formed only by the C composition.

[0052] Fig. 13 and Fig. Figure 14 shows detailed illustrations of the coating structure of the hard coating of each of the test samples 1-50 on end mills. In the column "INDIVIDUAL COMPOSITION LAYER", "A-LAYER", "B-LAYER" and "C-LAYER" each correspond to the A-layer described above. 32 , B-position 34 and C-position 36 Furthermore, in the column "NANOLAYER ACCOMPLAYMENT", "A-LAYER", "B-LAYER" and "C-LAYER" each correspond to the A-nanolayer described above. 32n , B-nanolayer 34n and carbon nanolayer 36n and “CHANGE LAYER (AB)”, “CHANGE LAYER (AC)” and “CHANGE LAYER (BC)” each the nanolayer change layers 38 , 40 , 42 Furthermore, "BORDERLINE LOCATION" is a corresponding boundary layer location to those described above. 44 , 52 , 62 , 94Each horizontal dash “-” in “A-LOCATION”, “B-LOCATION”, and “C-LOCATION” in the “INDIVIDUAL COMPOSITION LOCATION”, “NUMBER OF LAYER PAIRS”, and “THICKNESS” of “CHANGE LOCATION (AB)”, “CHANGE LOCATION (AC)”, and “CHANGE LOCATION (BC)” in the “NANO-LAYER CHANGE LOCATION” and “BORDER LOCATION” columns indicates that the corresponding layer or location is not provided for. Furthermore, none of the values ​​listed in the Fig. 13 and Fig. The 14 test samples shown, 1-50, are provided with the surface coating. Fig. 13 means that each grey part (each column provided with scattering points) means that a corresponding requirement regarding the thicknesses of the embodiment (of claim 1 of the invention) is not met, and the test specimens 1 - 6 are comparison products, while the test specimens 7 - 50 are products of the present invention.

[0053] Fig. Figure 9 is a schematic design view (schematic view) to illustrate an arc ion plating device 100, which is used to apply coatings to the tool substrate. 12 the hard coatings described above 30 , 50 , 60 , 70 , 80 , 90 or the hard coatings of the in Fig. 13 and Fig. The test samples 1-50 described in section 14 (hereinafter referred to simply as "hard coating 30 or the like" when not distinguished from one another) are to be formed. The arc ion plating device 100 is configured to apply the hard coating. 30 or the like on the surface of the tool substrate 12It is formed using arc ion plating, a type of PVD process, and is capable of continuously forming a variety of layer types with predetermined thicknesses, differing in composition, by changing the evaporation source (target) and the reaction gas. For example, if the hard coating 30 The nanolayer alternating layers are to be formed 40 , 38 and the prime location 32 alternately stacked on top of each other, according to the boundary surface situation 44 on the surface of the tool substrate 12 was trained. Fig. Figure 9 corresponds to a top view of the arc ion plating device 100 as seen from a top side of the arc ion plating device 100.

[0054] The arc ion plating device 100 comprises the following: a rotary table 154, which is to be driven to rotate about a rotational axis S extending essentially in a vertical direction, and which is intended to hold a plurality of workpieces, i.e., the plurality of tool substrates 12 , on which the hard coating is applied 30 or the like; a bias current source 156 for applying a negative bias to the tool substrates 12 , a process vessel in the form of a chamber 158, which contains the tool substrates 12The chamber 158 contains a reaction gas supply device 160 for supplying a reaction gas into the chamber 158; a gas discharge device 162 for removing a gas from the interior of the chamber 158, for example by means of a vacuum pump, in order to reduce the pressure inside the chamber 158; a first arc current source 164; a second arc current source 166, a third arc current source 168, and a fourth arc current source 170. The rotary table 154 is a disk-shaped table whose center corresponds to the axis of rotation S described above. The multitude of tool substrates 12 is arranged in such a way in an outer circumferential section of the rotary table 154 that each of the tool substrates 12 occupies a position that every substrate 12 essentially parallel to the axis of rotation S. While the tool substrates 12 Each of the tool substrates can be rotated around the axis of rotation S by the rotary table 154. 12be rotated around its axis. If the nitride is in the A-layer 32 , B-position 34 , C-position 36 or the like, the reaction gas supply device 160 introduces nitrogen gas into the chamber 158. The interior of the chamber 158 is, for example, brought into a vacuum state of about 2–10 Pa by the gas discharge device 162 and heated to a vapor separation temperature of, for example, about 300–600°C by a heater or the like, which is not shown in the drawings.

[0055] Each of the first arc current source 164, second arc current source 166, third arc current source 168, and fourth arc current source 170 is configured to generate an arc current between a corresponding anode 174, 178, 182, 186, and a corresponding cathode in the form of a first evaporation source 172, second evaporation source 176, third evaporation source 180, and fourth evaporation source 184, respectively, which consist of vapor deposition material. This arc discharge selectively causes vaporization material to evaporate from the corresponding first evaporation source 172, second evaporation source 176, third evaporation source 180, and fourth evaporation source 184. Once evaporated, the vaporization material becomes positive ions, which are deposited to each of the tool substrates. 12, onto which a negative (-) preload is applied. This means that each of the evaporation sources 172, 176, 180, 184 is formed by an alloy of composition A, B, and C, so that one of the evaporation sources can serve as an extra source, formed, for example, by the alloy of composition A, B, and C, which must be formed with a relatively large thickness to enable efficient coating formation. The number of evaporation sources can be three to correspond to the number of compositions consisting of composition A, B, and C.

[0056] The arc current sources 164, 166, 168, 170 described above are changed as needed in order to successively form the layers of predetermined compositions, thereby creating the hard coating30 or the like with a predetermined coating structure. The thickness of each layer can be adjusted by setting the rotational speed of the rotary table 154 and the switching time of a corresponding arc current source or sources 164, 166, 168, 170. A boundary section located between a multitude of layers with different compositions can be provided with a mixed layer formed by a mixture of two types of composition.

[0057] The results of a performance test of the hard coatings are now described. This test was carried out by producing test samples 1-50, in which the hard coating was treated with the respective parameters specified in the... Fig. 10 - Fig. 14 coating structures shown on a radius cutter, which is essentially the same as the end mill described above 10is the one that has the five cutting edges and passes through the tool substrate 12 made of hard metal, and were arranged with a diameter of 16 mm. Fig. Figure 15 is a view showing the test result, where “COATING HARDNESS” represents an HV (Vickers hardness) value of each hard coating measured in accordance with the Vickers hardness test method (JIS G0202, Z2244) under a condition specified by the hardness symbol HV0.025. Additionally, a cutting operation was performed in which each of the test samples 1–50 was used in accordance with a cutting test condition described below, and a cutting distance and wear width of a peripheral cutting edge were determined. 18The adjacent flank surface was measured, and the coating performance (durability) was assessed. More precisely, the wear width of the flank surface was measured by interrupting the cutting process as needed and then measuring the cutting distance when the wear width of the flank surface reached 0.2 mm or more. Then, those who exceeded the cutting distance were 20 Those with a cutting distance of 20 m or more were rated as successes ("O"), while those with a cutting distance of less than 20 m were rated as failures ("x"). The wear width was measured visually using a microscope (MM-400 / LM) manufactured by Nikon Corporation. - Cutting test condition - Workpiece material: Titanium alloy Cutting speed V: 70 m / min Speed ​​n: 1400 min -1 Feed rate: f = 0.09 mm / t, F = 630 mm / min Processing method: Side cutting Axial cutting depth ap: 28.8 mm Radial cutting depth ae: 3.2 mm

[0058] As from Fig. As can be seen from Section 15, each of the test samples 7-50, as a product of the present invention, exhibits a surface coating hardness (HV0.025) in the range of 2700-3300 (HV) and suggests excellent wear resistance and impact resistance (resistance to breakage and peeling during intermittent cutting). In contrast, test samples 1-6, the comparison products, showed values ​​of approximately 1800-2100 (HV). Regarding the cutting distance, each of the test samples 7-50, as a product of the present invention, was able to perform the cutting process over 20 m and demonstrated excellent durability. In contrast, each of the test samples 1-6, the comparison products, had a cutting distance of less than 20 m.

[0059] As described above, it is with the hard coating 30or the like of the end mill 10 according to the exemplary embodiment, in which three types of layers are formed, consisting of the single composition layer, which is divided by a layer from the A-layer. 32 , B-position 34 and C-position 36 is provided, and the two nanolayer alternating layers, each consisting of two of the nanolayer alternating layers 38 , 40 , 42By applying layers of predetermined thicknesses, it is possible to achieve excellent wear resistance, toughness, lubricity, and weld resistance. For example, excellent durability was achieved even during a cutting operation with a titanium alloy. Thanks to these properties, the high toughness prevents cracking and flaking of the hard coating during cutting operations with a titanium alloy or any other workpiece material such as carbon steel, stainless steel, cast iron, and alloy steel, or under harsh machining conditions such as high-speed machining and dry machining. 30 or the like, and accordingly increase the tool's service life.

[0060] Since the relationship T1 / T2 the thickness T1 of one type of individual composition layer to thickness T2of one of the two types of nanolayer alternating layers and the ratio T1 / T3 the thickness T1 of one type of individual composition layer to thickness T3 The other of the two types of nanolayer interlayers, both of which are in a range of 0.2 - 10, are also provided with corresponding thicknesses that ensure certain properties, making it possible to achieve performance such as wear resistance and weld resistance.

[0061] Furthermore, the coating hardness (HV0.025) of the hard coating 30 or similar in the range of 2700 - 3300 (HV), so that wear resistance and high toughness can be achieved with an excellent balance between them, thus preventing cracking and peeling of the hard coating. 30or similar factors can be suppressed, and consequently excellent durability can be achieved.

[0062] Furthermore, the hard coating can 80 from Fig. 7, which is not equipped with the interface position, can be trained at reduced coating training costs and the end mill 10 with the hard coating 80 It can be produced cost-effectively. On the other hand, it's problematic with hard coatings. 30 , 50 , 60 , 70 , 90 and the test samples 7 - 50, which are provided with the interface layer having the predetermined composition or compositions and the predetermined thickness, in each case possible, the adhesion strength of the adhesive coating 30 or the like on the tool substrate 12 to increase.

[0063] Furthermore, it has a hard coating 90 from Fig.8, which are connected to the surface layer 92 Provided that it has the predetermined composition or compositions and the predetermined thickness, it is possible to further improve certain coating performance characteristics such as wear resistance and weld resistance if the composition or compositions and the thickness of the surface layer are 92 be determined accordingly.

[0064] Furthermore, the end mill 10 an intermittently cutting tool that cuts through the peripheral cutting edge 18 and the final cutting edge 20 should perform a cutting process intermittently, so that the peripheral cutting edge 18 and the final cutting edge 20 A shock load is repeatedly applied and the peripheral cutting edge 18 and the final cutting edge 20 Therefore, heat slightly during the cutting process. When applying the hard coating30 or similar materials that have high wear resistance, toughness, lubricity and weld resistance, it is possible to increase the tool's service life.

[0065] Although the embodiment of the invention has been described in detail with reference to the accompanying drawings, it is understood that the described embodiment is merely one embodiment and that the present invention can be carried out with various modifications and improvements based on the knowledge of a person skilled in the art. Reference symbol list 10: End mill (element covered with a hard coating, intermittently cutting tool), 12: Tool substrate (substrate), 18: peripheral cutting edge (cutting edge), 20: End cutting edge (cutting edge), 30, 50, 60, 70, 80, 90: Hard coating, 32: A-location (individual composition location), 32n: A-nanolayer (nanolayer), 34: B-location (individual composition location), 34n: B-nanolayer (nanolayer), 36: C-location (single-composition location), 36n: C-nanolayer (nanolayer), 38, 40, 42: Nanolayer alternating layer, 44, 52, 62, 94: Border area location, 92: Surface layer, Total: Total thickness, T1: Thick single-composition layer, T2, T3: Thick nanolayer alternating layer QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2012

[0002] JP 35378 A

[0002] JP 2014

[0002] JP 54000834 A

[0002] JP 2008

[0002] JP 534297 A

[0002]

Claims

[1] A hard coating which is to be applied to the surface of a substrate in such a way that it covers the surface of the substrate, where the hard coating characterized by is that: The hard coating has a total thickness in the range of 0.5 - 20 µm and contains three types of layers that are stacked alternately on top of each other, wherein the three types of layers consist of a single-composition layer and two types of nanolayer alternating layers, wherein the single-composition layer is formed by an A-composition, a B-composition and a C-composition, and wherein the two types of nanolayer alternating layers contain nanolayers that are stacked alternately on top of each other and that are formed by two of three combinations consisting of a combination of the A-composition and the B-composition, a combination of the A-composition and the C-composition and a combination of the B-composition and the C-composition; The A composition is a nitride, which has the composition formula Al a Cr b Si c a dis represented, where the atomic ratios a, b, c, d satisfy 0.30 ≤ a ≤ 0.80, 0.15 ≤ b ≤ 0.65, 0 ≤ c ≤ 0.45, 0 ≤ d ≤ 0.10 and a + b + c + d = 1, where Si and α are optional additional components and where the optional additional component α is at least one type of element selected from B, C, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W; The B composition is a nitride, which has the composition formula Cr e B f Si g β h is represented, where the atomic ratios e, f, g, h satisfy 0.40 ≤ e ≤ 0.95, 0.05 ≤ f ≤ 0.30, 0 ≤ g ≤ 0.45, 0 ≤ h ≤ 0.10 and e + f + g + h = 1, where Si and β are optional additional components and where the optional additional component β is at least one type of element selected from C, Al, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W; The C composition is a nitride, which has the composition formula Al i Cr j (SiC) k YI is represented, where the atomic ratios i, j, k, I satisfy 0.20 ≤ i ≤ 0.85, 0.10 ≤ j ≤ 0.50, 0.03 ≤ k ≤ 0.45, 0 ≤ l ≤ 0.10 and i + j + k + l = 1 and where the optional additional component γ is at least one type of element selected from B, Ti, V, Y, Zr, Nb, Mo, Hf, Ta and W; the single composition layer has a thickness in the range of 0.5 - 1000 nm; and Each of the nanolayers that form the two types of nanolayer interlayers has a thickness in the range of 0.5 - 500 nm, and each of the two types of nanolayer interlayers has a thickness in the range of 1 - 1000 nm. [2] Hard coating according to claim 1, characterized by, that a ratio T1 / T2 of the thickness T1 of the single composition layer to the thickness T2 of one of the two types of nanolayer interlayers and a ratio T1 / T3 of the thickness T1 of the single composition layer to the thickness T3 of the other of the two types of nanolayer interlayers both lie in a range of 0.2 - 10. [3] Hard coating according to claim 1 or 2, characterized by , that a bottom layer of the single composition layer and the two types of nanolayer alternating layers, which are stacked alternately on top of each other, is to be arranged directly on a surface of the substrate. [4] Hard coating according to claim 1 or 2, characterized by , that: the hard coating contains an interface layer that is to be arranged between the hard coating and the substrate; The interface layer has a thickness in the range of 5 - 1000 nm and is provided by one of three types of layers, which are as follows: a single compositional layer formed by a combination of the A composition, the B composition and the C composition; a nanolayer interlayer containing two types of nanolayers, each formed by two of the A composition, the B composition and the C composition, and layered alternately such that each of the two types of nanolayers has a thickness of 0.5 - 500 nm; and a layer of metal nitride, metal carbonitride or metal carbide formed by at least one type of element selected from B, Al, Ti, Y, Zr, Hf, V, Nb, Ta, Cr and W. [5] Hard coating according to any one of claims 1-4, characterized by , that: the hard coating contains a surface layer that provides an outermost surface of the hard coating; the surface layer is provided by a single-composition layer formed by one of the A composition, the B composition and the C composition, or by an alternating nanolayer layer containing two types of nanolayers, each formed by two of the A composition, the B composition and the C composition, and stacked alternately such that each of the two types of nanolayers has a thickness in the range of 0.5 - 500 nm; and The surface layer has a thickness of 5 - 1000 nm. [6] Hard coating according to any one of claims 1-5, which characterized by is that: The coating hardness of the hard coating is in the range of 2700 - 3300. [7] Element covered with a hard coating, which has a substrate whose surface is partially or completely covered with a hard coating, wherein the element is covered with a hard coating characterized by is that: the hard coating is the hard coating according to one of claims 1-6. [8] Element covered with a hard coating according to claim 7, characterized by , that: the element covered with a hard coating is an intermittently cutting tool that has cutting edges and is to be rotated around an axis in such a way that it performs an intermittent cutting operation through the cutting edges.

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