Coated Cutting Tools

Abstract

The present invention relates to a method for producing a ceramic ceramic material comprising the steps of: i) cubic boron nitride (cBN) and TiC y N 1-y and a binder phase comprising: e) aluminum, the binder phase comprising: a net intensity ratio of Al to Ti in the substrate being expressed as less than 0.50, as measured by energy dispersive X-ray analysis (EDX); and / or f) tungsten, the net intensity ratio of W to Ti in the substrate being expressed as less than 0.035, as measured by XRD; and / or g) a ratio of the net peak height of the TiB2(101) peak to the net peak height of the TiCN(200) peak being less than 0.09, as measured by XRD; and / or h) a net intensity ratio of TiB2(101) peak to the net peak height of the TiCN(200) peak being less than 0.09, as measured by XRD. The present invention relates to a coated cutting tool comprising a binder phase comprising an impurity of α-alumina (116), expressed as a ratio of the net peak height of the α-alumina (116) peak to the net peak height of the CN(200) peak of less than 0.06, and ii) a coating deposited on a substrate comprising at least one nitride consisting of a nitride of one or more elements belonging to groups 4, 5 or 6 of the Periodic Table of the Elements, or a nitride of Al and / or Si together with one or more elements belonging to groups 4, 5 or 6 of the Periodic Table of the Elements. The present invention also relates to a method for providing such a coated cutting tool.

Description

[Technical Field]

[0001] The present invention relates to a coated cutting tool comprising a coating on a cubic boron nitride (cBN) based substrate and a method for making the same. [Background technology]

[0002] Coated cutting tools having a cubic boron nitride-based substrate, particularly for machining hardened steels, such as hardened ball bearing steels, are well known in the art. Traditionally, these tools include a cBN-based substrate in which cBN particles are dispersed in a Ti(C,N) binder phase. The Ti(C,N) binder phase typically contains impurities, such as W compounds, TiB2, and α-alumina. This has now been found to potentially result in reduced toughness and wear resistance. Such impurities may be unintentionally incorporated or added during processing of raw materials, or may form during the sintering process when the cBN particles and binder phase are subjected to high-pressure, high-temperature conditions to produce a sintered composite. Subsequent grinding of a sintered composite containing a binder phase with such impurities in the cBN-based substrate often results in surface damage and reduced adhesion of coatings deposited on the substrate.

[0003] PVD-coated substrates are known to offer the advantage of improved wear resistance compared to uncoated substrates. However, the adhesion of PVD coatings is not always satisfactory, resulting in limited lifetime. The art teaches the use of an intermediate layer between the substrate and a coating containing a non-metallic, metallic, or interdiffused layer to improve adhesion. This means that the PVD coating is not deposited on the substrate so that it is in direct contact with the substrate. Such intermediate layers are generally weak and therefore do not provide optimal bond strength. Therefore, it is desirable to further improve the adhesion between the substrate and the coating and extend tool life. Thus, an object of the present invention is to improve the adhesion of coatings without an intermediate layer, particularly (Ti,Al)N coatings deposited on cBN-based substrates, e.g., PVD-deposited coatings. A further object of the present invention is to impart improved wear resistance, lifetime, and toughness to the coated cutting tool. A further object is to reduce the diffusion of workpiece material into the coating. Summary of the Invention

[0004] The present invention provides i) Cubic boron nitride (cBN) and TiC y N 1-y wherein 0≦y≦1, and a binder phase comprising: a) aluminum, where the net intensity ratio of Al to Ti in the substrate is expressed as less than 0.50, as measured by energy dispersive X-ray analysis (EDX); and / or b) tungsten, where the net intensity ratio of W to Ti in the substrate is expressed as less than 0.035; and / or c) TiB2, expressed as a ratio of the net peak height of the TiB2(101) peak to the net peak height of the TiCN(200) peak, as measured by XRD, of less than 0.09; and / or d) α-alumina, expressed as a ratio of the net peak height of the α-alumina (116) peak to the net peak height of the TiCN (200) peak, as measured by XRD, of less than 0.06. a substrate containing impurities of ii) a coating deposited on a substrate, comprising at least one layer composed of nitrides of one or more elements belonging to group 4, 5 or 6 of the periodic table of the elements, or nitrides of Al and / or Si together with one or more elements belonging to group 4, 5 or 6 of the periodic table of the elements; The present invention relates to a coated cutting tool comprising:

[0005] According to one embodiment, the bonded phase comprises at least impurities b) and d) as described above.

[0006] According to one embodiment, the cubic boron nitride contained in the substrate is present in an amount ranging from 20 to 75, for example 25 to 70 or 30 to 70, preferably 40 to 70, most preferably 50 to 70 or 55 to 70 volume % relative to the total volume of the substrate. As used herein, the term TiCN(200) peak refers to the peak at which TiCN is present in the TiC 0.7 N 0.3 It is considered to be.

[0007] According to one embodiment, at least 70% by volume, preferably at least 80% by volume, most preferably at least 90% by volume, or at least 95% by volume, or all of the hard material contained in the substrate is cubic carbon nitride (cBN).

[0008] Preferably, the binder phase is TiC y N 1-y with the possibility of adding transition metal carbides, nitrides or carbonitrides, where, for example, 0.4≦y≦0.9 or 0.6≦y≦0.8. According to one embodiment, the binder phase is 80-100, more preferably 90-95% by volume of TiC. y N 1-y where y<1.

[0009] According to another embodiment, the binder phase comprises 80 to 100, more preferably 90 to 95, volume % TiC.

[0010] According to one embodiment, the binder phase comprises 80-100, more preferably 90-95% by volume of TiN.

[0011] According to one embodiment, the cBN particles in the binder phase have a bimodal particle size distribution with average particle sizes ranging from 0.1 to 1.2 μm and 2 to 6 μm, preferably 0.2 to 0.6 μm and 3 to 5 μm, respectively. Improved toughness may be obtained using a bimodal particle size distribution in the specified ranges.

[0012] In many conventional substrates, impurities, including W from processing equipment and O from the atmosphere or mixing liquids, are introduced during raw material processing and sintering of the composite, and small amounts of Al are usually added as a sintering aid, which, when subjected to high temperature and pressure conditions during sintering, leads to the formation of W containing impurities, as well as TiB2 and α-Al2O3, among others, that form in the binder phase.

[0013] In particular, certain levels of these impurities have been found to adversely affect the adhesion of the coating to the substrate and therefore the tool life of the coated cutting tool.

[0014] According to one embodiment, the impurity oxygen, expressed as the net intensity ratio of O to Ti in the substrate, as measured by energy dispersive X-ray analysis (EDX), is less than 0.036, or less than 0.030, or substantially zero, or greater than 0.005, or greater than 0.010, but below any upper limit specified herein.

[0015] According to one embodiment, the impurity tungsten, expressed as the net intensity ratio of W to Ti in the substrate as measured by energy dispersive X-ray analysis (EDX), is less than 0.030, or less than 0.020, or less than 0.010, such as less than 0.005, or less than 0.0028, or less than 0.0026, or substantially zero, or greater than 0.0010, or greater than 0.0015, but still below any upper limit specified herein.

[0016] According to one embodiment, the impurity aluminum, expressed as the net intensity ratio of Al to Ti in the substrate as measured by energy dispersive X-ray analysis (EDX), is less than 0.49, or less than 0.48, or less than 0.47, or less than 0.46, or substantially zero, or greater than 0.05, or greater than 0.20, or greater than 0.30, but below any upper limit specified herein.

[0017] XRD measurements of the substrates according to the invention showed that virtually no TiB2 reflections and weak diffractions from alpha-alumina occurred for the sintered composites, meaning that the sintered composites had no or substantially no TiB2 content and only a small amount of alpha-alumina.

[0018] According to one embodiment, the TiB2, expressed as the ratio of the net peak height of the TiB2(101) peak to the net peak height of the TiCN(200) peak, as measured by XRD, is less than 0.07, or less than 0.05, or less than 0.03, or more preferably less than 0.02, or substantially zero, or greater than 0.005 but below any upper limit specified herein.

[0019] According to one embodiment, the α-alumina, expressed as the ratio of the net peak height of the α-alumina (116) peak to the net peak height of the TiCN (200) peak, as measured by XRD, is less than 0.056, or less than 0.055, or less than 0.054, or less than 0.053, or less than 0.052, or less than 0.051, or less than 0.050, or less than 0.040, or substantially zero, or greater than 0.01, or greater than 0.02, but below any upper limit specified herein.

[0020] According to one embodiment, the surface roughness Rz of the substrate measured by peak-to-valley height measurement using FIB-SEM cross section. cBN is in the range of 0.60 μm to 3 μm, preferably 0.60 μm to 1.5 μm, and most preferably 0.75 μm to 1.00 μm.

[0021] According to one embodiment, the surface of the substrate has a coverage of cubic boron nitride of at least 55% and less than 95% of the surface area, as measured by the line intersecting method.

[0022] According to one embodiment, the surface of the substrate has a coverage of cubic boron nitride of at most 95% of the surface area, for example at most 90% or at most 85% or at most 80% or at most 75%, as measured by the intersection line method.

[0023] According to one embodiment, the substrate surface has a hardness in the range of 2,200 to 3,000 Vickers, preferably 2,500 to 2,800, and most preferably 2,600 to 2,700 Vickers. The hardness is calculated by measuring 100 times along the cutting edge of the substrate with a maximum load of 2 mN.

[0024] According to one embodiment, the indentation module EIT is in the range of 500 to 700 GPa, preferably 530 to 600 GPa.

[0025] According to one embodiment, the content of the binder phase ranges from 25 to 75% by volume relative to the total volume of the substrate.

[0026] According to one embodiment, the coated cutting tool further comprises a coated substrate, the substrate and coating as defined herein comprising a cutting tip attached to the substrate.

[0027] According to one embodiment, the cutting tip is provided as a brazed tip on a support.

[0028] According to one embodiment, the cutting tip is brazed to the support via a braze joint covering the area between the support and the substrate.

[0029] As used herein, the term "sintered composite" refers to a TiC y N 1-y The term "sintered composite" is intended to include any sintered body comprised of a binder phase comprising at least one cubic boron nitride (cBN) hard material. Preferably, the "sintered composite" is precision ground to form a substrate, for example, with a diamond grinding wheel using a digitally controlled precision grinding machine as is well known in the art, or by other known methods of forming a substrate, such as laser fabrication. In the grinding process or other methods of forming a substrate, the surface of a cBN sintered composite is often damaged by chipping of cBN particles or smearing of the binder phase, for example, to the point of loss of toughness or coating adhesion.

[0030] In a preferred embodiment, the substrate is attached to the support by brazing or sintering before grinding. According to one embodiment, the support may comprise one or more additional hard materials, for example tungsten carbide (WC).

[0031] The term "surface" in the context of a sintered composite is intended to include a zone extending perpendicularly from the surface in contact with the deposited coating to the bulk of the sintered composite. The thickness of the zone can be compared to the particle size of the abrasive material and can be, for example, up to about 3,000 nm or 1,500 nm, e.g., up to 1,200 nm or 500 nm, or up to 200 nm.

[0032] According to one embodiment, the at least one nitride layer is preferably CrN, TiN, CrAlN, TiAlN, NbN, TiSiN, more preferably CrN, CrAlN, TiAlN, NbN, and TiSiN, and most preferably TiAlN or Ti x Al 1-x N, where x ranges from 0.3 to 0.7.

[0033] According to one embodiment, the coating further comprises a ZrN layer deposited on said at least one nitride layer.

[0034] According to one embodiment, the adhesion ρ of said at least one nitride layer to the substrate, measured by Calotest, is <0.6, preferably <0.5 or <0.35 or <0.2.

[0035] According to one embodiment, the grains of said at least one nitride, e.g. (Ti,Al)N layer, have an average columnar grain width, measured at a distance of at most 2 μm from the lower contact surface of the (Ti,Al)N layer, i.e. 2 μm from the substrate surface, 80-250 nm, preferably 80-175 nm, most preferably 100-150 nm.

[0036] According to one embodiment, said at least one nitride, for example (Ti,Al)N, has a thickness of 0.1 to 15 μm, for example 0.5 to 10 μm, preferably 1 to 6 μm, most preferably 2 to 4 μm or 2 to 3 μm.

[0037] According to one embodiment, said at least one nitride sublayer type in the multilayer, for example a (Ti,Al)N sublayer type in the multilayer, preferably has an average thickness of 1 to 100 nm, preferably 1.5 to 50 nm, most preferably 2 to 20 nm.

[0038] According to one embodiment, for different nitride sub-layer types, for example (Ti,Al)N sub-layer types, the ratio of average thicknesses between different (Ti,Al)N sub-layer types is 0.5 to 2, preferably 0.75 to 1.5.

[0039] According to one embodiment, the nitride layer, e.g., (Ti,Al)N, has a Vickers hardness of ≥3000 HV (15 mN load), preferably 3500-4200 HV (15 mN load). Hardness measurements were performed using a PICODENTOR® HM500 hardness measuring device (Helmut Fischer GmbH, Sindelfingen-Maichingen, Germany) with a Vickers pyramid at a maximum load of 15 mN, with a loading and unloading duration of 20 seconds and a load hold duration of 5 seconds. Evaluation of the measurements was performed according to the Oliver-Pharr method.

[0040] According to one embodiment, the coating comprises a (Ti,Al)N layer that is either a single monolithic layer or a multilayer of two or more alternating (Ti,Al)N sublayer types that differ in their composition of the sublayers, which may have an average thickness ranging from 1 to 100 nm, for example.

[0041] According to one embodiment, the (Ti,Al)N grains are preferably columnar, with increasing (Ti,Al)N grain width with increasing thickness of the (Ti,Al)N layer.

[0042] The present invention provides i) Cubic boron nitride (cBN) and TiC y N 1-yand a binder phase comprising: a) aluminum, where the net intensity ratio of Al to Ti in the substrate is expressed as less than 0.50, as measured by energy dispersive X-ray analysis (EDX); and / or b) tungsten, where the net intensity ratio of W to Ti in the substrate is expressed as less than 0.035; and / or c) TiB2, expressed as a ratio of the net peak height of the TiB2(101) peak to the net peak height of the TiCN(200) peak, as measured by XRD, of less than 0.09; and / or d) α-alumina, expressed as a ratio of the net peak height of the α-alumina (116) peak to the net peak height of the TiCN (200) peak, as measured by XRD, of less than 0.06. providing a substrate containing the impurities; ii) a coating deposited on a substrate, comprising at least one layer composed of nitrides of one or more elements belonging to group 4, 5 or 6 of the periodic table of the elements, or nitrides of Al and / or Si together with one or more elements belonging to group 4, 5 or 6 of the periodic table of the elements; The present invention relates to a method for making a coated cutting tool, comprising:

[0043] According to one embodiment, the bonded phase comprises impurities b) and d).

[0044] According to one embodiment, the surface coverage of the cubic boron nitride is at least 55%, such as at least 65% or at least 75% of the surface area, as measured by the intersection line method.

[0045] According to one embodiment, the surface of the substrate is ion etched to such an extent that the coverage of cubic boron nitride is still at most 95% of the surface area, for example at most 90%, or at most 85%, or at most 80%, or at most 75%, as measured by the intersection line method.

[0046] According to one embodiment, the ion etching is performed by plasma ion etching.

[0047] According to one embodiment, the ion etching time is in the range of 30 to 300 minutes, for example, 60 to 200 minutes, 60 to 150 minutes, or 90 to 150 minutes. According to one embodiment, the etching time is in the range of 60 to 120 minutes.

[0048] According to one embodiment, the sintered composite is etched to an average depth of >200 nm, preferably 200-1,500 nm, more preferably 400-1,200 nm, most preferably 600-1,000 nm, for example 700-900 nm.

[0049] According to one embodiment, at least one layer composed of said nitride is deposited on the substrate by high power impulse magnetron sputtering (HIPIMS).

[0050] According to one embodiment, the coating is deposited on the substrate by a PVD method, such as cathodic sputtering (sputter deposition), cathodic vacuum arc evaporation (arc PVD), ion plating, electron beam evaporation, and laser ablation. Cathodic sputtering, such as magnetron sputtering, reactive magnetron sputtering, and high-power impulse magnetron sputtering (HIPIMS), as well as arc evaporation deposition, are some of the most frequently used PVD processes for coating cutting tools that can be used for coating deposition. According to one embodiment, the coating is preferably deposited by high-power impulse magnetron sputtering (HIPIMS).

[0051] In high-power impulse magnetron sputtering (HIPIMS), the magnetron is operated in pulsed mode at high current densities, resulting in improved layer structures in the form of denser layers, particularly due to improved ionization of the sputtered material. The target current density in the HIPIMS process typically exceeds that of standard DC-MS. Depending on the material, up to 100% ionization of the sputtered particles by HIPIMS can be achieved. At the same time, the short-term high power and discharge current density acting on the target impart an increased degree of ionization, which can alter the growth mechanism and the bonding of the layer to the underlying material, thereby having an impact on the layer properties.

[0052] In the HIPIMS process, finely crystalline and even columnar crystalline layer structures can be achieved, characterized by associated improved wear behavior and longer service life compared to DC-MS layers.

[0053] According to one embodiment, a ZrN layer may be deposited on at least one nitride layer, such as a (Ti,Al)N layer, and may consist of a single layer or multiple layers of ZrN arranged one on top of the other. However, if the coating layer consists of multiple layers of ZrN arranged one on top of the other, they are deposited from one or more Zr targets, but in multiple steps of a HIPIMS process with different deposition parameters.

[0054] According to one embodiment, one or more layers of ZrN having a total thickness between 1 nm and 700 nm, preferably between 100 nm and 300 nm, are deposited on at least one of said layers composed of nitride, for example a (Ti,Al)N layer.

[0055] The ZrN layer may have a decorative function, but it can also function as a wear detector, indicating whether the tool has been used and, if so, its wear level. When no further layers are applied to the ZrN layer, the ZrN coating layer gives the tool a golden yellow color, which can be varied between different shades by adjusting the HIPIMS process parameters. For example, the brightness of the golden yellow color can be varied by adjusting the nitrogen partial pressure in the HIPIMS process. Deposition of a ZrN layer in the HIPIMS process, like that of a TiAlN layer, offers advantages in terms of process control, resulting from the deposition of a functional layer over a coating layer. Furthermore, providing a ZrN layer offers tribochemical advantages, particularly in machining titanium alloys used in the aerospace industry and machining stainless steels. Deposition of the ZrN layer does not require application of a sputtering target made of the material being deposited for the ZrN layer.

[0056] Preferably, TiAlN is deposited by varying the partial pressure of nitrogen gas during the first and second parts of the process, whereby nitrogen has a higher partial pressure during the second part of the process and a lower partial pressure during the first part of the process. WO2016 / 128504 further discloses process conditions how TiAlN can be deposited, which can also be applied in the present invention.

[0057] According to one embodiment, the deposition of any coating layer is >0.2 kW / cm 2 , preferably >0.4kW / cm 2 , most preferably >0.7 kW / cm 2 Peak power density of preferably >0.2A / cm 2 , more preferably >0.3A / cm 2 , most preferably >0.4 A / cm 2 and preferably at a maximum peak voltage of ≧1,000 V.

[0058] According to one embodiment, the (Ti,Al)N layer and optionally any additional layers are deposited by high power impulse magnetron sputtering (HIPIMS), wherein an electric pulse is applied to each sputtering target of the material to be deposited in a coating chamber, the electric pulse being ≥ 1,000 W / cm 2 The amount of energy delivered to the sputtering target exceeds the maximum power density in a pulse of 1000 keV.

[0059] In a further embodiment, the nitride layer, e.g., the (Ti,Al)N layer and any further layers deposited on the (Ti,Al)N layer, are applied by high power impulse magnetron sputtering (HIPIMS), whereby electric pulses are applied to respective sputtering targets of the material to be deposited in a coating chamber, the electric pulses being ≥ 1 A / cm 2 , preferably ≥ 3 A / cm 2 The discharge current density of the pulse is

[0060] According to one embodiment, the maximum peak voltage is in the range of 1,000 to 3,000V, preferably 1,500 to 2,500V.

[0061] According to one embodiment, the substrate temperature during magnetron sputtering is preferably 350 to 600°C, or 400 to 500°C.

[0062] According to one embodiment, the DC bias voltage used in the HIPIMS process is 20-150V, preferably 30-100V.

[0063] According to one embodiment, the average power density in the HIPIMS process is between 20 and 100 W cm -2 , preferably 30 to 75 W cm -2 The range is.

[0064] According to one embodiment, the pulse length used in the HIPIMS process is in the range of 2 μs to 200 ms, preferably 10 μs to 100 ms, more preferably 20 μs to 20 ms, and most preferably 40 μs to 1 ms.

[0065] According to one embodiment, the cutting tool is an insert, a drill or an end mill.

[0066] The present invention also relates to the use of the coated cutting tools for machining hardened steels, such as ball bearing steels or other hardened steels having a hardness higher than 40 HRC, preferably higher than 55 HRC, most preferably higher than 59 HRC. [Brief explanation of the drawings]

[0067] [Figure 1] FIG. 1 is a schematic diagram of a calotest. [Figure 2] FIG. 1 is a schematic diagram showing the boundary between the substrate and the coating after the Calotest. DETAILED DESCRIPTION OF THE INVENTION

[0068] method EDX: The aluminum, oxygen, and tungsten contents in the binder phase of the cBN substrate were estimated and shown as net intensity ratios relative to the titanium content by energy dispersive X-ray spectroscopy (EDX) analysis. The binder phase analysis was performed using a scanning electron microscope with an electron energy of 15 keV and an OctanePlus X-ray detector (energy resolution at the MnK peak of 130 eV, detection area of ​​10 mm). 2 This was done on polished metallographic sections using an EDAX analysis system equipped with a Peltier cooling system. M , O K and Al K The net integrated peak intensities of each element are expressed as the net integrated Ti to indicate the content of each element W, O, and Al as a net intensity ratio to the titanium content. K The peak was separated.

[0069] XRD (Seifert GE3003PTS, Cu X-ray source, 1 mm polycapillary pinhole, 0.4° parallel-plate collimator, Meteor 0D energy-dispersive detector); to estimate the content of the impurity phases AlO and TiB in the TiCN binder phase, X-ray diffraction data were recorded in Bragg-Brentano geometry. The net peak heights of the α-alumina (116) peak and the TiB (101) peak were divided by the net peak height of the TiCN (200) peak to obtain the relative peak height ratio of the impurity phases as a measure of the impurity phase content of the binder phase.

[0070] Calorie analysis: The Calo test was carried out by creating a grinding mark (= Calo) in the coating by grinding with a rotating metal ball (3), as shown in Figure 1. Optical microscope images were obtained from the Calo. The metal ball (3) was positioned between a magnetically fixed insert and a shaft. Rotation of the shaft rotates the ball (3), and holes are created in the coating by grinding with a 1 μm diamond suspension. The rotation speed of the shaft and the grinding time were selected to create a hole through the coating until the substrate (1) was exposed in the center of the Calo. A sharp boundary between the substrate (1) and the coating (2) indicates good adhesion. A smeared boundary between the coating (2) and the substrate (1) indicates poor adhesion.

[0071] The deepest visible substrate diameter was approximately in the range of d = 200 μm to 450 μm. Measurements were performed close to the corners, approximately 1 mm from each edge. When determining the quality of the adhesion, radii r1 and r2 were measured. r1 corresponds to the radius of the coating at a distance t from the interface between the substrate and the coating at radius r2. By measuring r1 and r2 and knowing the radius of the rotating globule R (1.5 cm in our example), the thickness t extending perpendicularly from the interface between the substrate and the coating, from radius r2 to radius r1, can be calculated according to equation (1) (see Figures 1 and 2). t=sqrt(R 2 -r12 )-sqrt(R 2 -r2 2 ) (1)

[0072] Radius r2 was calculated by measuring the area of ​​the removed material as enclosed by radii r1 and r2.

[0073] The total thickness of the entire coating corresponds to the difference between the radii r3 and r2, i.e.: t total coating =r3-r2 (2)

[0074] The ratio ρ, which is independent of the size of the formed Callot circle, is defined as the coating thickness at r2 divided by the total thickness of the coating corresponding to r3, i.e.: ρ=t / t 全コーティング (3)

[0075] The lower the value of ρ, the better the adhesion.

[0076] Intersection method: The surface coverage of cBN particles on uncoated substrates was estimated by drawing a 60 μm line measuring its length on a scanning electron micrograph at an appropriate magnification, e.g., 2,000x, and then marking all line segments that bisect the cBN particle. The combined lengths of all these line segments were then added and divided by the total line length to obtain a cBN coverage number. A total of five lines were drawn, and the surface coverage of the cBN particle was calculated as the average of the five cBN coverage numbers.

[0077] Cross-sectional analysis: A Zeiss Crossbeam 540 FIB (Focused Ion Beam Analysis) instrument was used to fabricate the cross-sections of the cBN substrates by ion beam milling using Ga ions. The surface roughness of the substrates was measured as the peak-to-valley distance Rz perpendicular to the substrate surface in the cross-section over a measurement length of 25.3 μm. cBNThe peaks and valleys used for the measurements (height measurements) correspond to the highest peaks and lowest valleys, respectively, within the measured length. [Example]

[0078] Example 1 As specified below, commercially available substrates, DHA650 from Element Six and SBS600 from Iljin Diamond, were treated by ion etching and then coating steps with the process conditions listed in Table 6. Ion etching was performed on an Oerlikon Balzers Ingenia system. The ion etching rate was 7.5 nm / min for all etched samples. Equipment type: Balzers Ingenia S3P Temperature: 430℃ Bias voltage: 200V Substrate rotation: 50% Argon: 570sccm Output: 2 x 15kW T-pulse: 0.05 ms

[0079] Base material: DHA650: 65% by volume of cBN and 35% by volume of a TiCN-based binder phase (TiC 0.7 N 0.3 ) and unavoidable impurities combined. The net intensity ratio of impurities to Ti, as measured by EDX, was: TIFF2025500333000001.tif38170

[0080] The impurity phase relative peak heights, as measured by XRD, were as follows: TIFF2025500333000002.tif33170

[0081] And the surface coverage of the cBN particles was measured by the line intersection method as follows (results in %): TIFF2025500333000003.tif75170

[0082] SBS600 (reference substrate): 60% by volume of cBN and 40% by volume of a TiCN-based binder phase combined with unavoidable impurities. The net intensity ratio of impurities to Ti was: TIFF2025500333000004.tif38170

[0083] The impurity phase relative peak heights, as measured by XRD, were as follows: TIFF2025500333000005.tif32170

[0084] coating: W:(Ti 40 Al 60 )N / ZrN T:(Ti 40 Al 60 )N / (Ti 75 Si 25 )N

[0085] The performance of the coated cutting tools was evaluated during continuous rotation of 100CrMo7-3 steel through-hardened to 62HRc. The cutting speed was 220 m / min, the depth of cut was 0.2 mm, and the feed rate was 0.15 mm / rev. The flank wear scar was measured and the end of tool life was determined when the flank wear reached v b = 0.20 mm. TIFF2025500333000006.tif63170

[0086] As can be seen in Table 1, the tool life of the present invention DHA650 / W (70 min ion etching time) was 28 min, which can be compared to DHA650 / T (15 min ion etching time) which has a tool life of 19 min. Both T and W coatings were prepared using the same Ti deposited on the substrate DHA650. 40 Al 60 The W and T coatings were comparable in quality because they had an N layer. As a result, the Ti in direct contact with the treated substrate40 Al 60 The same treatment resulted in the same adhesion for both the W and T coatings with an N layer. Thus, a 9-minute longer tool life difference (47% increase) was obtained by ion etching the DHA650 substrate for 70 minutes (corresponding to an average etch depth of 525 nm) rather than the specified ion etching rate of 15 minutes (112.5 nm average etch depth). The increased tool life was realized due to the improved adhesion when exposing the substrate to the longer ion etching time.

[0087] A further effect of this was that less flaking occurred on the DHA650 substrate / W ​​coating (invention) than on the comparative SBS600 substrate / T coating (reference).

[0088] In Calotest, improved adhesion was observed, with DHA650 / W (in accordance with the invention) obtaining a measured p value of 1 / 6, compared to 2 / 3 for the reference SBS600 / T. The increased tool life and improved adhesion secondary to the increased etch depth (as a direct effect of longer etching times at constant etch rate) and associated with the higher cBN surface coverage of the invention was surprising, as one skilled in the art would have expected poorer adhesion of a coating deposited on a cBN material compared to the adhesion obtained on a substrate surface with a TiCN bonding phase, i.e., enhanced cBN coverage.

[0089] The hardness of the etched substrate surface obtained by 100 measurements with a maximum load of 2 mN along the cutting edge was as follows: 15-minute etching EIT=456GPa HV=2,145 Vickers 105 min etching EIT=560GPa HV=2,650 Vickers

[0090] The etching effect was uniform on the flank, rake and edge.

Claims

1. i) cubic boron nitride (cBN) and TiC ｙ N １－ｙ wherein 0≦y≦1; and a binder phase comprising: a) aluminum, where the net intensity ratio of Al to Ti in the substrate is expressed as less than 0.50, as measured by energy dispersive X-ray analysis (EDX); and / or b) tungsten, where the net intensity ratio of W to Ti in the substrate is expressed as less than 0.035; and / or c) TiB relative to the net peak height of the TiCN(200) peak as measured by XRD ２ TiB expressed as a net peak height ratio of the (101) peak less than 0.09 ２ (101); and / or d) α-alumina(116), expressed as a ratio of the net peak height of the α-alumina(116) peak to the net peak height of the TiCN(200) peak, as measured by XRD, of less than 0.

06. a substrate containing impurities of ii) a coating deposited on a substrate, comprising at least one layer composed of nitrides of one or more elements belonging to group 4, 5 or 6 of the periodic table of the elements, or nitrides of Al and / or Si together with one or more elements belonging to group 4, 5 or 6 of the periodic table of the elements; Coated cutting tools including:

2. 10. The coated cutting tool of claim 1, wherein the surface of the substrate has a coverage of cubic boron nitride that is at least 55% and less than 95% of the surface area, as measured by the intersection line method.

3. 2. The coated cutting tool of claim 1, wherein the content of cubic boron nitride in the substrate is in the range of 25 to 75 volume % based on the total volume of the substrate.

4. The coated cutting tool of claim 1 , wherein the coating further comprises a ZrN layer deposited on the at least one nitride layer.

5. 2. The coated cutting tool of claim 1, wherein the adhesion p of the nitride layer to the substrate is <0.6 as measured by Calotest.

6. The coated cutting tool of claim 1 further comprising a support, said substrate and said coating comprising a cutting tip attached to said support.

7. 7. The coated cutting tool of claim 6, wherein the cutting tip is provided as a brazed tip on a substrate.

8. 7. The coated cutting tool of claim 6, wherein the cutting tip is brazed to the support via a braze joint covering the area between the support and the substrate.

9. The peak-to-valley distance Rz of the substrate of the coated cutting tool measured by FIB-SEM cross section. ｃＢＮ 2. The coated cutting tool of claim 1, wherein the roughness is expressed as being in the range of 0.60 to 3 μm.

10. The bonded phase is b. Tungsten, wherein the net intensity ratio of W to Ti in the substrate is expressed as less than 0.035; and d. α-alumina (116), expressed as a ratio of the net peak height of the α-alumina (116) peak to the net peak height of the TiCN (200) peak, as measured by XRD, of less than 0.

06.

10. The coated cutting tool of claim 1, comprising:

11. The coated cutting tool of claim 1 , wherein the coating deposited on the substrate comprises at least one layer of TiAlN.

12. i) cubic boron nitride (cBN) and TiC ｙ N １－ｙ and a binder phase comprising: a) aluminum, where the net intensity ratio of Al to Ti in the substrate is expressed as less than 0.50, as measured by energy dispersive X-ray analysis (EDX); and / or b) tungsten, where the net intensity ratio of W to Ti in the substrate is expressed as less than 0.035, as measured by energy dispersive X-ray analysis (EDX); and / or c) TiB relative to the net peak height of the TiCN(200) peak as measured by XRD ２ TiB expressed as a net peak height ratio of the (101) peak less than 0.09 ２ (101); and / or d) α-alumina(116), expressed as a ratio of the net peak height of the α-alumina(116) peak to the net peak height of the TiCN(200) peak, as measured by XRD, of less than 0.

06. providing a substrate containing the impurity; ii) a coating deposited on a substrate, comprising at least one layer composed of nitrides of one or more elements belonging to group 4, 5 or 6 of the periodic table of the elements, or nitrides of Al and / or Si together with one or more elements belonging to group 4, 5 or 6 of the periodic table of the elements; 1. A method of making a coated cutting tool, comprising:

13. The method of claim 12, wherein ion etching is carried out until a surface coverage of cubic boron nitride is obtained that is at least 55% of the surface area, as measured by the intersection line method.

14. The method of claim 12 wherein the ion etching is performed by plasma ion etching.

15. The method according to claim 12, wherein the etching time is in the range of 60 to 120 minutes, preferably 60 to 100 minutes.

16. The method of claim 12, wherein the sintered composite is etched to an average depth of 400 to 1200 nm.

17. The method of claim 12 , wherein the nitride layer is deposited on the substrate by high power impulse magnetron sputtering (HIPIMS).

18. The bonded phase is b. Tungsten, wherein the net intensity ratio of W to Ti in the substrate is expressed as less than 0.035, as measured by energy dispersive X-ray analysis (EDX); and d. α-alumina (116), expressed as a ratio of the net peak height of the α-alumina (116) peak to the net peak height of the TiCN (200) peak, as measured by XRD, of less than 0.

06.

13. The method of claim 12, wherein the impurities are:

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