Coated cutting tool

Abstract

The invention relates to a coated cutting tool. Specifically, the present invention relates to a coated cutting tool and a method of making such a coated cutting tool comprising a substrate coated with a multi-layer wear resistant coating comprising a layer of alpha-Al2O3 and a layer of titanium carbonitride, TixCyN1-y, deposited on the layer of alpha-Al2O3, where 0.85 < = x < = 1.3 and 0.4 < = y < = 0.85, wherein TixCyN1-y has a texture coefficient TC (hkl) measured by X-ray diffraction using CuK [alpha] radiation and [theta]-2 [theta] scan and defined according to the Harris formula, where I (hkl) is the measured intensity (integrated area) of (hkl) reflection; i0 (hkl) is the standard intensity according to the standard powder diffraction data of the JCPDS cards No. 42-1489; n is the number of reflections used in the calculation, and wherein the (hkl) reflections used are (1 1), (2 0), (2 0), (3 1), (3 1), (4 0) and (4 2); and TC (1 1) > = 3.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 201880019670.4, filed on March 26, 2018, entitled "Coated Cutting Tool". Technical Field

[0002] This invention relates to a coated cutting tool. Specifically, it relates to a coated cutting tool for metal chip forming machining, and more precisely, a coated cutting tool comprising a substrate coated with multiple layers of wear-resistant coating, said coating comprising an alumina layer and a titanium carbonitride layer. The cutting tool disclosed herein is particularly suitable for applications requiring high wear resistance, such as turning, milling, and drilling of metallic materials like alloy steel, carbon steel, or toughening steel. Background Technology

[0003] The deposition of thin refractory coatings on cutting tools has been widely used in the machining industry for decades. Coatings such as TiCN and Al2O3 have been shown to improve the wear resistance of cutting inserts when cutting a wide variety of materials. A combination of an inner TiCN layer and an outer α-Al2O3 layer can be found on many commercially available cutting tools designed for turning or milling, for example, steel. However, with technological advancements, higher demands are being placed on cutting tools. Therefore, there is a need for wear-resistant coated cutting tools that exhibit wear resistance during metal cutting operations. Summary of the Invention

[0004] This disclosure provides coated cutting tools with wear-resistant properties during cutting operations, particularly coated cutting tools with improved wear resistance, such as higher resistance to crater wear and lateral wear. The invention also provides a method for manufacturing coated cutting tools having the above-described properties.

[0005] According to an aspect exemplified herein, a coated cutting tool is provided, comprising a substrate coated with a multilayer wear-resistant coating, the coating comprising an α-Al₂O₃ layer and titanium carbonitride (Ti) deposited on the α-Al₂O₃ layer. x C y N 1-y Layer, wherein 0.85 ≤ x ≤ 1.3, preferably 1.1 ≤ x ≤ 1.3, and 0.4 ≤ y ≤ 0.85, wherein Ti x C y N 1-y The texture coefficient TC(hkl) is measured by X-ray diffraction using CuKα radiation and θ-2θ scanning and defined according to the Harris formula:

[0006] ,

[0007] in

[0008] I(hkl) is the measured intensity (integral area) of the reflection from (hkl);

[0009] I0(hkl) is the standard intensity based on the standard powder diffraction data of JCPDS card No. 42-1489;

[0010] n is the number of reflections used in the calculation, and the (hkl) reflections used are (1 1 1), (2 0 0), (2 2 0), (3 1 1), (3 3 1), (4 2 0), and (4 2 2); and TC(1 1 1) ≥ 3.

[0011] It has been unexpectedly shown that the Ti of the cutting tool disclosed herein... x C y N 1-y The layer exhibits unexpectedly high hardness. Increased hardness in the coating is typically associated with improved wear resistance, such as resistance to crater wear and lateral wear. As used herein, the term "cutting tool" includes, but is not limited to, replaceable cutting tool inserts, indexable cutting tool inserts, and solid cutting tools.

[0012] This disclosure is based on the understanding that cutting tools with improved hardness titanium carbonitride layers can be achieved by coating them with a coating, thereby improving wear resistance in machining applications. The coating comprises an α-Al₂O₃ layer and titanium carbonitride (Ti) deposited on the α-Al₂O₃ layer. x C y N 1-y Layer, and wherein the Ti x C y N 1-y It has a particularly preferred orientation. More specifically, such properties can be achieved by having a titanium carbonitride (Ti) layer comprising an α-Al₂O₃ layer. x C y N 1-y The coating layer is achieved using cutting tools, in which Ti was found. x C y N 1-y The geometrically equivalent crystal plane {111} is preferably oriented parallel to the substrate, and is expressed in this paper as the texture factor TC (1 1 1) ≥ 3.

[0013] The Ti x C y N 1-y The layer is typically deposited using medium-temperature chemical vapor deposition (MTCVD) at temperatures of 600°C–900°C. The α-Al₂O₃ is typically deposited using chemical vapor deposition (CVD) at temperatures of 800°C–1200°C. The Ti…x C y N 1-y The layer is typically deposited directly on top of the α-Al₂O₃ layer without an intermediate layer. However, the scope of this disclosure also includes layers contained in Ti. x C y N 1-y An implementation where a thin intermediate layer exists between the Ti deposited layer and the α-Al₂O₃ layer. x C y N 1-y The α-Al₂O₃ grains are preferably columnar.

[0014] Furthermore, the coating disclosed herein also provides Ti x C y N 1-y Excellent adhesion between the layers and the substrate.

[0015] The multilayer coating covers at least the area of ​​the cutting tool involved in the cutting operation, and at least the area exposed to crater wear and / or lateral wear. Alternatively, the entire cutting tool may be coated with the multilayer coating of this disclosure.

[0016] In some embodiments of this disclosure, the α-Al₂O₃ layer has a texture coefficient TC(hkl) defined by X-ray diffraction measurements using CuKα radiation and θ-2θ scanning, and according to the Harris formula, where I(hkl) is the measured intensity (integral area) of the (hkl) reflection, I₀(hkl) is the standard intensity based on standard powder diffraction data from JCPDS card 00-010-0173, n is the number of reflections used in the calculation, and the (hkl) reflections used are (1 0 4), (1 1 0), (1 1 3), (0 2 4), (1 1 6), (2 1 4), (3 0 0), and (0 0 12); and TC(0 0 12) ≥ 7, preferably TC(0 0 12) ≥ 7.2. The high intensity from the (0 0 12) reflection has proven advantageous: it promotes subsequent Ti... x C y N 1-y A way of strong <1 1 1> texture of layers.

[0017] In some implementations, the Ti x C y N 1-yThe thickness of the layer is 1µm-10µm, preferably 1µm-5µm, more preferably 1µm-3µm, and most preferably 1µm-2µm. The thickness of the α-Al2O3 layer is 0.1µm-7µm, preferably 0.1µm-5µm, 0.1µm-2µm, or 0.3µm-1µm.

[0018] In some embodiments, the coating includes an additional titanium carbonitride layer (Ti) located between the substrate and the α-Al₂O₃ layer. u C v N 1-v Where 0.85 ≤ u ≤ 1.3, preferably 1.1 ≤ u ≤ 1.3, and 0.4 ≤ v ≤ 0.85. The Ti u C v N 1-v The layer can be deposited directly on the substrate. However, the scope of this disclosure also includes deposition on the substrate and Ti. u C v N 1-v An implementation may include thin intermediate layers, such as TiN layers, between the layers. Preferably, the Ti... u C v N 1-v The Ti was deposited by MTCVD at a temperature of 600℃-900℃. u C v N 1-v The thickness of the layer is typically 3µm-20µm, preferably 3µm-10µm, 3µm-7µm, or 3µm-5µm.

[0019] In some embodiments, the Ti located between the α-Al2O3 layer and the substrate u C v N 1-v The layer has a texture coefficient TC(hkl) measured by X-ray diffraction using CuKα radiation and θ-2θ scanning and defined according to the Harris formula, in which I(hkl) is the measured intensity (integral area) of the (hkl) reflection, I0(hkl) is the standard intensity according to JCPDS card No. 42-1489, n is the number of reflections, and the reflections used in the calculation are (1 1 1), (2 0 0), (2 2 0), (3 1 1), (3 3 1), (4 2 0), and (4 2 2); and where TC(4 2 2) ≥ 3, preferably TC(4 2 2) ≥ 3.5. In one embodiment, the Ti u C v N 1-v The layer exhibits TC(3 1 1) + TC(4 2 2) ≥ 4; ≥ 5; ≥ 6; or ≥ 7. This is from the Ti layer.u C v N 1-v The high intensity of (4 2 2) reflection has proven its advantage: it is a way to promote strong <0 0 1> texture in subsequent α-Al2O3 layers.

[0020] In some implementations, the Ti x C y N 1-y The average hardness of the layer is higher than that of the Ti u C v N 1-v The layer has a high average hardness. This hardness is preferably measured using a Berkovich indenter via nanoindentation, and the hardness H is defined as H = (P / 24.5h) / (P / 24.5h). c 2 ), where P is the maximum contact pressure exerted by the indenter on the coating, h c The indentation depth is determined by the indenter. Hardness is measured by indentation on the flat surface of the layer in a direction perpendicular to the outer surface of the layer. The indentation is preferably made under a constant load of 3000 μN / min. c =110nm depth.

[0021] In some implementations, the Ti x C y N 1-y The average hardness of the layer is greater than 25 GPa, preferably greater than 26 GPa, more preferably greater than 27 GPa, and even more preferably greater than 30 GPa. The hardness is preferably measured using a Berkovich indenter via nanoindentation, and the hardness H is defined as H = (P / 24.5h) c 2 ), where P is the maximum contact pressure exerted by the indenter on the coating, h c The indentation depth is created by the indenter. The indentation is preferably created with a constant load of 3000 μN / min. c A depth of 110 nm can also be considered. Other indenters known in the art can also be considered. Ti x C y N 1-y The advantage of its high hardness lies in the fact that it provides improved wear resistance for coated cutting tools.

[0022] In some embodiments, the total thickness of the coating is 4µm-32µm, preferably 4.5µm-20µm or 5µm-15µm.

[0023] In some embodiments, the substrate is selected from cemented carbide, cermet, ceramic, steel, or cubic boron nitride. These substrates have the hardness and toughness suitable for the coatings of this disclosure.

[0024] In some embodiments, the substrate of the coated cutting tool is made of cemented carbide comprising 4 wt%-12 wt% Co, preferably 6 wt%-8 wt% Co, optionally 0.1 wt%-10 wt% of cubic carbides, nitrides or carbonitrides of group IVb, Vb and VIb metals from the periodic table, preferably Ti, Nb, Ta or combinations thereof, and the balance being WC.

[0025] In some embodiments, the substrate is a cemented carbide having a surface region rich in a binder phase. Measured from the surface of the substrate toward the core, the thickness of the binder-rich surface region is preferably 5µm-35µm. The binder phase content in the binder-rich region is, on average, at least 50% higher than the binder phase content in the core of the substrate. The binder-rich surface region improves the toughness of the substrate. A substrate with high toughness is preferred for cutting operations such as turning of steel.

[0026] In some embodiments, the substrate is a cemented carbide having a surface region that is substantially free of cubic carbides. The thickness of the substantially cubic carbide-free surface region is preferably 5µm-35µm, measured from the surface of the substrate toward the core. "Substantially free" means that no cubic carbides are observed when the cross-section is visually analyzed under an optical microscope.

[0027] In some embodiments, the substrate is a cemented carbide having a surface region rich in binder phase as disclosed above combined with a surface region substantially free of cubic carbides as disclosed above.

[0028] According to other aspects described herein, a method for manufacturing a coated cutting tool having a substrate is also provided, the method comprising the following steps:

[0029] a) Depositing Ti on the substrate by MTCVD at a temperature of 600℃-900℃. u C v N 1-v layer,

[0030] b) The Ti was subjected to CVD at a temperature of 800℃-1200℃. u C v N 1-v An α-Al₂O₃ layer is deposited on top of the layer;

[0031] c) In an atmosphere containing TiCl4, CH3CN, N2, and H2, titanium carbonitride (Ti) is deposited on an α-Al2O3 layer by MTCVD at a temperature of 600°C–900°C under partial pressures of 3 vol%–13 vol% H2 and 83 vol%–94 vol% N2, preferably 3 vol%–10 vol% H2 and 85 vol%–93 vol% N2.x C y N 1-y layer,

[0032] Wherein, the Ti x C y N 1-y The texture coefficient TC(hkl) is measured by X-ray diffraction using CuKα radiation and θ-2θ scanning and defined according to the Harris formula:

[0033] ,

[0034] in

[0035] I(hkl) is the measured intensity (integral area) of the reflection from (hkl);

[0036] I0(hkl) is the standard intensity based on the standard powder diffraction data of JCPDS card No. 42-1489;

[0037] n is the number of reflections used in the calculation, and the (hkl) reflections used are (1 1 1), (2 0 0), (2 2 0), (3 1 1), (3 3 1), (4 2 0), and (4 2 2); and TC(1 1 1) ≥ 3.

[0038] It has been unexpectedly discovered that by using a low amount of H2 in the CVD reactor, Ti with the texture according to this disclosure can be obtained. x C y N 1-y According to this disclosure, a low H2 content should be expressed as an amount in the range of 3% to 13% by volume, preferably 3% to 10% by volume. Furthermore, a high N2 content, such as in the range of 83% to 94% by volume, preferably 85% to 93% by volume, may be advantageous. The total gas pressure in the reactor is preferably around 80 mbar.

[0039] The coated cutting tool manufactured according to the method can be further defined as described above with reference to the coated cutting tool of the present invention. In particular, the Ti... x C y N 1-y The thickness of the coating can be 1µm-10µm, preferably 1µm-5µm, more preferably 1µm-3µm, and most preferably 1µm-2µm.

[0040] In some embodiments, the α-Al₂O₃ layer of the method preferably has a texture coefficient TC(hkl) defined by X-ray diffraction measurements using CuKα radiation and θ-2θ scanning, and according to the Harris formula, where I(hkl) is the measured intensity (integrated area) of the (hkl) reflection, I₀(hkl) is the standard intensity based on standard powder diffraction data from JCPDS card No. 00-010-0173, n is the number of reflections used in the calculation, and the (hkl) reflections used are (1 0 4), (1 1 0), (1 1 3), (0 2 4), (1 1 6), (2 1 4), (3 0 0), and (0 0 12); and TC(0 0 12) ≥ 7, preferably TC(0 0 12) ≥ 7.2.

[0041] In some embodiments of the method, the thickness of the α-Al2O3 layer is preferably 0.1µm-7µm, more preferably 0.3µm-5µm, 0.3µm-2µm, or 0.3µm-1µm.

[0042] In some embodiments of the method, the Ti u C v N 1-v The thickness of the layer is 3µm-20µm, preferably 3µm-10µm, 3µm-7µm, or 3µm-5µm.

[0043] In some embodiments of the method, the Ti located between the α-Al2O3 layer and the substrate u C v N 1-v The layer has a texture coefficient TC(hkl) measured by X-ray diffraction using CuKα radiation and θ-2θ scanning and defined according to the Harris formula, in which I(hkl) is the measured intensity (integral area) of the (hkl) reflection, I0(hkl) is the standard intensity according to JCPDS card No. 42-1489, n is the number of reflections, and the reflections used in the calculation are (1 1 1), (2 00), (2 2 0), (3 1 1), (3 3 1), (4 2 0), and (4 2 2); and where TC(4 2 2) ≥ 3.

[0044] In some embodiments of the method, the Ti x C y N 1-y The average hardness of the layer is higher than that of the Ti u C v N 1-v The average hardness of the layer is high.

[0045] In some embodiments of the method, the Ti x C y N 1-y The average hardness of the layer is greater than 25 GPa, preferably greater than 26 GPa or greater than 27 GPa.

[0046] In some embodiments of the method, the total thickness of the coating is 4µm-32µm, preferably 4.5µm-20µm or 5µm-15µm.

[0047] In some embodiments of the method, the substrate is selected from cemented carbide, cermet, ceramic, steel, or cubic boron nitride. Detailed Implementation

[0048] The coating cutting tools and methods of this disclosure will be described in more detail below by way of non-limiting embodiments.

[0049] Definitions and methods

[0050] CVD coating

[0051] The CVD coating was prepared in a Bernex BPX 325S radial flow reactor with a height of 1250 mm and a diameter of 325 mm.

[0052] Texture coefficient, TC

[0053] The crystal planes of a crystal are defined by Miller indices h, k, and l. One way to indicate preferred growth, i.e., finding a set of geometrically equivalent crystal planes {hkl} that preferentially align parallel to the substrate, is to use the Harris formula to calculate the texture factor TC(hkl) based on a prescribed set of XRD reflections measured on the corresponding sample. The intensity of the XRD reflection is normalized using a JCPDS card, which indicates the XRD reflection intensity of the same material, such as TiCN, but with a random orientation, such as in powder form. At least compared to the XRD reflections used in the Harris formula for determining the texture factor TC, a texture factor TC(hkl) > 1 for a layer of crystalline material indicates that the grains of the crystalline material are more frequently oriented with their {hkl} crystal planes parallel to the substrate surface than randomly distributed.

[0054] The term "columnar" grain is intended herein to refer to grains that grow from the bottom of a layer toward the outer surface of the layer and typically extend in that direction. Columnar grains differ from equiaxed grains in that equiaxed grains continuously re-nucleate during layer growth.

[0055] X-ray diffraction (XRD) measurement

[0056] The crystallographic phase composition and out-of-plane orientation of the thin film were evaluated by θ-2θ X-ray diffraction using a Philips MRD-XPERT diffractometer equipped with a first-stage hybrid monochromator and a second-stage X-ray microscope. The measurements were performed using Cu-Ka radiation at a voltage of 45 kV and a current of 40 mA. A ½-degree anti-scattering slit and a 0.3 mm receiving slit were used. The diffraction intensity from the coating cutting tool was measured in the 2θ range of 30° to 140°, i.e., in the range of incident angle θ from 15° to 70°.

[0057] Data analysis, including background subtraction and graph fitting, was performed using PANalytical's X'PertHighScore Plus software. The output of this program (the integral peak area of ​​the graph fitting curve) was then used to calculate the texture factor of the layer by comparing the measured intensity data of a specific layer (e.g., TiCN or α-Al2O3 layer) with the standard intensity data according to the JCPDS card using the Harris formula disclosed above.

[0058] Because the layer is a finite-thickness film, the relative intensities of a pair of peaks at different 2θ angles differ from those in the case of a bulk sample due to the varying path lengths through the layer. Therefore, when calculating the TC value, a thin-film correction is applied to the integral peak area intensity extracted from the fitted curve, taking into account the linear absorption coefficient of the layer. This is because other possible layers, such as Ti, are also considered. x C y N 1-y The layer will affect the entry into Ti x C y N 1-y The X-ray intensity of the layer and the entire coating must be considered, so the linear absorption coefficients of the corresponding compounds in the layer also need to be corrected for. If the α-Al₂O₃ layer is located in, for example, Ti... x C y N 1-y Below this layer, this also applies to X-ray diffraction measurements of the α-Al₂O₃ layer. Alternatively, in Ti... x C y N 1-y Additional layers above the α-Al₂O₃ layer, such as TiN, can be removed using methods that substantially do not affect XRD measurements, such as chemical etching or mechanical polishing. This is in contrast to the TiN layer located beneath the α-Al₂O₃ layer and the substrate. u C v N 1-v In the implementation of the layer, the lower Ti is performed u C v N 1-v Before X-ray diffraction measurements of the layer, the outer Ti layer needs to be removed. x Cy N 1-y layer.

[0059] Hardness measurement

[0060] The hardness of the titanium carbonitride layer was measured using nanoindentation. Nanoindentations were fabricated using a CSM UNHT nanoindenter with a Berkovich-tipped diamond indenter. The indentations were preferably created under a constant load of 3000 μN / min. c =110nm depth. Hardness was measured on a flat outer surface or layer after gentle surface polishing (using 6μm diamond slurry) to reduce surface roughness. Equipment-based measurements were performed on fused silica to ensure optimal indenter performance. Hardness H was defined as H = (P / 24.5h) c 2 ), where P is the maximum contact pressure exerted by the indenter on the coating, h c The depth of the indentation is created by an indenter. The indentation is made perpendicular to the surface of the layer. Any outer layers need to be removed, for example, by chemical etching or mechanical polishing, before hardness measurement can be performed.

[0061] Example 1 - Ti on Sapphire x C y N 1-y

[0062] Sample preparation and analysis

[0063] Ti was grown on a polished single-crystal c-sapphire (001) substrate in a Bernex 325 hot-wall CVD reactor with a height of 1250 mm and a diameter of 325 mm at a temperature of 830 °C. x C y N 1-y .

[0064] The experimental conditions used for depositing the coatings of this disclosure (samples 1 and 2) and the coating of the comparative example (sample 3) are shown in Table 1. The coatings were grown to a thickness of approximately 1.5 μm.

[0065] Table 1. Experimental conditions in the CVD chamber.

[0066]

[0067] X-ray diffraction (XRD measurement) and texture coefficient

[0068] XRD analysis of the Ti content of the coating was performed. x C y N 1-yThe layers were analyzed, and the texture indices of the (hkl) reflections of TiCN (11 1), (2 0 0), (2 2 0), (3 1 1), (3 3 1), (4 2 0), and (4 2 2) were determined as described herein. Thin film corrections were performed on the raw XRD data. The results are shown in Table 2.

[0069] Table 2. Ti x C y N 1-y texture coefficient

[0070]

[0071] Hardness measurement

[0072] Ti x C y N 1-y The hardness of the layer was measured using a CSM UNHT nanoindenter with a Berkovich-tipped diamond indenter, and calculated as described above. The average hardness after 36 indentations was taken as the coating hardness. The results are shown in Table 3.

[0073] Table 3. Hardness Measurement

[0074]

[0075] Example 2 - Ti on cemented carbide x C y N 1-y

[0076] Sample preparation and analysis

[0077] The cemented carbide substrate of ISO type CNMG120408 for turning is made of 7.2 wt% Co, 2.7 wt% Ta, 1.8 wt% Ti, 0.4 wt% Nb, 0.1 wt% N, and the balance WC, comprising a Co-rich surface region of about 25 µm from the surface of the substrate to a depth of about 25 µm into a substantially cubic carbide-free body. The composition of the cemented carbide is therefore about 7.2 wt% Co, 2.9 wt% TaC, 1.9 wt% TiC, 0.4 wt% TiN, 0.4 wt% NbC, and 86.9 wt% WC.

[0078] Using the well-known MTCVD technique, with TiCl4, CH3CN, N2, HCl, and H2, the blade of sample 4 was first coated with a thin TiN layer of approximately 0.4 μm at 885 °C, followed by a TiN layer of approximately 12 µm. u C v N 1-v Layer. In Ti u C v N 1-vThe initial stage of MTCVD deposition of the layers used a TiCl4 / CH3CN volume ratio of 6.6, followed by a period using a TiCl4 / CH3CN ratio of 3.7. TiN and Ti u C v N 1-v Details of the deposition are shown in Table 4.

[0079] Table 4. TiN and Ti2O3 samples 4 via MTCVD u C v N 1-v sediment

[0080]

[0081] MTCVD Ti at 1000℃ via a process consisting of four independent reaction steps u C v N 1-v A 1µm-2µm thick binder layer is deposited on top of the layer. First, HTCVD Ti is performed using TiCl4, CH4, N2, HCl, and H2 at 400 mbar. u C v N 1-v The deposition process proceeded in three steps: a first step (TiCNO-1) using TiCl4, CH3CN, CO, N2, and H2 at 70 mbar; a second step (TiCNO-2) using TiCl4, CH3CN, CO, N2, and H2 at 70 mbar; and a third step (TiCNO-3) using TiCl4, CO, N2, and H2 at 70 mbar. During the third and fourth deposition steps, some gases were continuously varied, as shown by the first start level and the second stop level in Table 5. Prior to the subsequent Al2O3 nucleation, the binder layer was oxidized in a mixture of CO2, CO, N2, and H2 at 55 mbar for 4 minutes. Details of the binder layer deposition are shown in Table 5.

[0082] Table 5. Adhesive layer deposition in sample 4

[0083]

[0084] An α-Al₂O₃ layer was deposited on top of the adhesive layer using CVD. All α-Al₂O₃ layers were deposited in two steps at 1000°C and 55 mbar. The first step produced an α-Al₂O₃ layer of approximately 0.1 μm thickness using 1.2 vol% AlCl₃, 4.7 vol% CO₂, 1.8 vol% HCl, and the balance H₂. The second step, as disclosed below, produced a total α-Al₂O₃ layer of approximately 10 µm thickness.

[0085] The second step of the α-Al2O3 layer deposition used 1.2% AlCl3, 4.7% CO2, 2.9% HCl, 0.58% H2S and the balance H2, see Table 6.

[0086] Table 6. Second α-Al₂O₃ deposition step of Sample 4 (remaining H₂)

[0087]

[0088] On top of the α-Al₂O₃ layer, a 1.7 µm thick Ti layer was deposited using MTCVD. x C y N 1-y Layer. The Ti x C y N 1-y The layers were deposited at 830 °C and 80 mbar using 3.3 v / v TiCl4, 0.5 v / v CH3CN, 8.75 v / v H2 and the balance N2, see Table 7.

[0089] Table 7. Deposition of the outermost TiCN layer

[0090]

[0091] X-ray diffraction (XRD measurement) and texture coefficient

[0092] XRD analysis was performed on the outermost Ti layer of the coating. x C y N 1-y Layer, inner Ti u C v N 1-v The XRD layers and α-Al₂O₃ layers were analyzed, and the texture factor of the (hkl) reflection was determined as described herein. Thin film correction was performed on the raw XRD data. The results are shown in Tables 8-10.

[0093] Table 8. Texture coefficient of the outermost TiCN layer of sample 4

[0094]

[0095] Table 9. Texture coefficient of the inner TiCN layer of sample 4

[0096]

[0097] Table 10. Texture coefficients of the α-Al₂O₃ layer in sample 4

[0098]

[0099] Hardness measurement

[0100] outermost Tix C y N 1-y The hardness of the layer was measured by creating nanoindentations using a CSM UNHT nanoindenter with a Berkovich-tipped diamond indenter, and calculated as described above. The average hardness after 15 indentations was taken as the hardness of the outermost Ti layer. x C y N 1-y The hardness of the layer was measured. The outermost Ti layer was... x C y N 1-y The average hardness of the layer is 26.7 GPa.

Claims

1. A coated cutting tool comprising a substrate coated with a multilayer wear-resistant coating, said multilayer wear-resistant coating comprising an α-Al₂O₃ layer and titanium carbonitride (Ti) deposited on said α-Al₂O₃ layer. x C y N 1-y Layer, wherein 0.85 ≤ x ≤ 1.3, preferably 1.1 ≤ x ≤ 1.3, and 0.4 ≤ y ≤ 0.85, wherein Ti x C y N 1-y The average hardness of the layer, measured by nanoindentation using a Berkovich indenter, is greater than 25 GPa, and the Ti in the layer... x C y N 1-y The texture coefficient TC(hkl) is measured by X-ray diffraction using CuKα radiation and θ-2θ scanning and defined according to the Harris formula: ， in I(hkl) is the measured intensity (integral area) of the reflection from (hkl); I0(hkl) is the standard intensity based on the standard powder diffraction data of JCPDS card No. 42-1489; n is the number of reflections used in the calculation, and the (hkl) reflections used are (1 1 1), (2 0 0), (2 20), (3 1 1), (3 3 1), (4 2 0), and (4 2 2); and Where TC(1 1 1) ≥ 3.

2. The coated cutting tool according to claim 1, wherein the α-Al₂O₃ layer has a texture coefficient TC(hkl) defined according to the Harris formula by X-ray diffraction measurements using CuKα radiation and θ-2θ scanning, wherein, I(hkl) is the measured intensity (integrated area) of the (hkl) reflection, I0(hkl) is the standard intensity based on the standard powder diffraction data of JCPDS card No. 00-010-0173, n is the number of reflections used in the calculation, and the (hkl) reflections used are (1 0 4), (1 1 0), (1 1 3), (0 2 4), (1 1 6), (2 1 4), (3 0 0) and (0 0 12); and TC(0 0 12) ≥ 7, preferably TC(0 0 12) ≥ 7.

2.

3. The coated cutting tool according to claim 1 or 2, wherein Ti x C y N 1-y The thickness of the layer is 1µm-10µm, preferably 1µm-5µm, 1µm-3µm, or 1µm-2µm.

4. The coated cutting tool according to any one of the preceding claims, wherein the thickness of the α-Al2O3 layer is 0.3µm-7µm, preferably 0.3µm-5µm, 0.3µm-2µm, or 0.3µm-1µm.

5. The coated cutting tool according to any one of the preceding claims, wherein the coating comprises additional titanium carbonitride (Ti) located between the substrate and the α-Al₂O₃ layer. u C v N 1-v Layer, wherein 0.85 ≤ u ≤ 1.3, preferably 1.1 ≤ u ≤ 1.3, and 0.4 ≤ v ≤ 0.

85.

6. The coated cutting tool according to claim 5, wherein Ti u C v N 1-v The thickness of the layer is 3µm-20µm, preferably 3µm-10µm, 3µm-7µm, or 3µm-5µm.

7. The coated cutting tool according to claim 5 or 6, wherein the Ti layer located between the α-Al₂O₃ layer and the substrate... u C v N 1-v The layer has a texture coefficient TC(hkl) measured by X-ray diffraction using CuKα radiation and θ-2θ scanning and defined according to the Harris formula, where, I(hkl) is the measured intensity (integral area) of the reflection at (hkl), I0(hkl) is the standard intensity according to JCPDS card No. 42-1489, n is the number of reflections, and the reflections used in the calculation are (1 1 1), (2 0 0), (22 0), (3 1 1), (3 3 1), (4 2 0), and (4 2 2); and Where TC(4 2 2) ≥ 3.

8. The coated cutting tool according to any one of claims 5-7, wherein the Ti x C y N 1-y The average hardness of the layer is higher than that of the Ti u C v N 1-v The average hardness of the layer is high.

9. The coated cutting tool according to any one of the preceding claims, wherein the Ti x C y N 1-y The average hardness of the layer is greater than 26 GPa, preferably greater than 27 GPa.

10. The coated cutting tool according to any one of the preceding claims, wherein the total thickness of the coating is 4µm-32µm, preferably 4.5µm-20µm or 5µm-15µm.

11. The coated cutting tool according to any one of the preceding claims, wherein the substrate is selected from cemented carbide, cermet, ceramic, steel or cubic boron nitride.

12. A method for manufacturing a coated cutting tool having a substrate, the method comprising the steps of: a) Depositing Ti on the substrate by MTCVD at a temperature of 600℃-900℃. u C v N 1-v layer; b) The Ti was subjected to CVD at a temperature of 800℃-1200℃. u C v N 1-v An α-Al₂O₃ layer is deposited on top of the layer; c) Titanium carbonitride (Ti) is deposited on an α-Al₂O₃ layer by MTCVD at a temperature of 600°C–900°C in an atmosphere containing TiCl₄, CH₃CN, N₂, and H₂ in amounts of 3–13 vol% H₂ and 83–94 vol% N₂. x C y N 1-y layer, in The Ti x C y N 1-y The texture coefficient TC(hkl) is measured by X-ray diffraction using CuKα radiation and θ-2θ scanning and defined according to the Harris formula: ， in I(hkl) is the measured intensity (integral area) of the reflection from (hkl); I0(hkl) is the standard intensity based on the standard powder diffraction data of JCPDS card No. 42-1489; n is the number of reflections used in the calculation, and the (hkl) reflections used are (1 1 1), (2 0 0), (2 20), (3 1 1), (3 3 1), (4 2 0), and (4 2 2); and Where TC(1 1 1) ≥ 3.

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