Coated article comprising a refractory coating

Abstract

Coated article, comprehensive: a substrate; and a coating adhering to the substrate, which is deposited by chemical vapor deposition (CVD), wherein the coating comprises a refractory layer with a matrix phase containing α-aluminum oxide, θ-aluminum oxide or mixtures thereof, and with at least one particle phase dispersed within the matrix phase, wherein the particle phase comprises particles in the nano- to submicron range formed from at least one oxycarbide and / or oxycarbonitride of one or more metals selected from the group consisting of aluminum and group IVB metals.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to coated articles having refractory coatings and, more particularly, to refractory coatings deposited on cutting tools by chemical vapor deposition (CVD). BACKGROUND

[0002] Cutting tools, including cemented carbide cutting tools, are used in both coated and uncoated forms for machining various metals and alloys. To increase wear resistance, performance, and service life of the cutting tool, one or more layers of refractory material are applied to the cutting tool surfaces. For example, TiC, TiCN, TiN, and / or Al2O3 are applied to cemented carbide substrates by chemical vapor deposition (CVD) and physical vapor deposition (PVD). Although refractory coatings are effective in suppressing wear and extending service life in a wide variety of applications, they have increasingly reached their performance limits on single- or multi-layer constructions of the aforementioned refractory materials, necessitating the development of new coating architectures for cutting tools.

[0003] US Pat. No. 8,221,838 B2 discloses a CVD process for producing a coated body, by means of which various coating schemes can be created on a substrate. In one embodiment, the coating scheme comprises alternating layers of titanium-aluminum oxycarbonitride and aluminum oxide. In another embodiment, the coating scheme includes an intermediate layer that has varying proportions of aluminum and oxygen on the one hand, and titanium, carbon, and nitrogen on the other, along its thickness.

[0004] US 2009 / 0214787 A1 describes a process and a resulting coating comprising nanocrystals dispersed in an amorphous ceramic matrix. The nanocrystals can consist of nitrides, carbides, or carbonitrides of a transition metal. SUMMARY

[0005] In one aspect, articles comprising refractory coatings utilizing alumina-based hybrid nanocomposite architectures are described herein. According to the invention, a coated article comprises a substrate and a coating deposited by CVD adhered to the substrate, the coating comprising a composite refractory layer having a matrix phase comprising α-alumina, θ-alumina, or mixtures thereof, and at least one particulate phase dispersed within the matrix phase, the particulate phase comprising nanoscale (<100 nm) to submicron-sized particles formed from at least one of an oxycarbide and oxycarbonitride of one or more metals selected from the group consisting of alumina and Group IVB metals.In some embodiments, the particles may, for example, have regular spacing, irregular spacing, or a patterned distribution within the matrix phase. Furthermore, the composite refractory layer may further comprise nanoscale titanium-containing band structures. In some embodiments, such band structures are crystalline and have at least one dimension ranging from 1 nm to 100 nm.

[0006] These and other embodiments are set forth in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 illustrates a cutting tool substrate according to an embodiment described herein. Fig. 2 is a scanning electron microscopy (SEM) image of a portion of a composite refractory layer according to some embodiments described herein. Fig.3 is a scanning transmission electron microscopy (STEM) image of a portion of a composite refractory layer according to some embodiments described herein. Fig. 4(a) is a bright field transmission electron microscopy (TEM) image of a portion of a composite refractory film according to some embodiments described herein with the inlay being a selected area electron diffraction (SAED) illustrating the polycrystalline morphology of the film. Fig. 4(b) is the corresponding dark field TEM image of the composite refractory layer of the Fig. 4(a). Fig. Figure 4(c) is a TEM image showing the dimensions of a single columnar grain of a composite refractory layer according to one of the embodiments described herein. Fig.Figure 4(d) is a convergent beam electron diffraction (CBED) of the columnar grain of the Fig. 4(c). Fig. 5(a) is an energy dispersive spectroscopy (EDS) line profile of a portion of a composite refractory layer according to one of the embodiments described herein. Fig. Figure 5(b) is an EDS spot analysis of a nanoparticle in the matrix phase of the composite refractory layer. Fig. Figure 5(c) is an EDS spot analysis of the Al2O3 matrix of the composite refractory layer according to one of the embodiments described herein. Fig. Figure 5(d) is an EDS spot analysis of a band structure of the nanoscale composite refractory layer according to one embodiment described herein. Fig. 6(a) is a bright field TEM image of a portion of a composite refractory layer according to some embodiments described herein. Fig.6(b) is a STEM image of a portion of a composite refractory layer according to some embodiments described herein. DETAILED DESCRIPTION

[0007] In one aspect, articles comprising refractory coatings utilizing alumina-based hybrid nanocomposite architectures are described herein. Articles having such refractory coatings are, in some embodiments, suitable for high wear and / or abrasion applications, including metal cutting applications. A coated article described herein comprises a substrate and a coating deposited by CVD adhered to the substrate, wherein the coating includes a composite refractory layer having a matrix phase comprising alumina and at least one particulate phase within the matrix phase, wherein the particulate phase comprises nanoscale to submicron-sized particles formed from at least one of an oxycarbide and oxycarbonitride of one or more metals selected from the group consisting of aluminum and Group IVB metals.In addition, the composite refractory layer may further comprise titanium-containing nanoscale band structures. In some embodiments, such band structures are crystalline and have at least one dimension ranging from 1 nm to 100 nm. As shown in the microscopy images provided herein, the nanoscale band structures may have a 2-dimensional morphology.

[0008] Turning now to specific components, coated articles described herein comprise a substrate. A coated article may comprise any substrate not inconsistent with the objectives of the present invention. For example, a substrate may be a cutting tool or a tool used in wear applications. Cutting tools include, but are not limited to, indexable inserts, end mills, or drills. Indexable inserts may have any desired geometry according to the ANSI standard for milling, interrupted cutting, or turning applications. Substrates of coated articles described herein may be formed from cemented carbide, carbide, ceramic, cermet, polycrystalline cubic boron nitride, steel, or other alloys. A cemented carbide substrate, in some embodiments, comprises tungsten carbide (WC). WC may be present in a cutting tool substrate in an amount of at least about80 weight percent or in an amount of at least about 85 weight percent. In addition, metallic binders of cemented carbide may include cobalt or a cobalt alloy. For example, cobalt may be present in a cemented carbide substrate in an amount ranging from 1 weight percent to 15 weight percent. In some embodiments, cobalt is present in a cemented carbide substrate in an amount ranging from 5 to 12 weight percent or from 6 to 10 weight percent. Further, a cemented carbide substrate may have a binder-enriched zone beginning at the surface of the substrate and extending inward from the surface of the substrate.

[0009] Cemented carbide substrates may further comprise one or more additives, for example, one or more of the following elements and / or their compounds: titanium, niobium, vanadium, tantalum, chromium, zirconium, and / or hafnium. In some embodiments, titanium, niobium, vanadium, tantalum, chromium, zirconium, and / or hafnium form solid solution carbides with the WC of the substrate. In these embodiments, the substrate may comprise one or more solid solution carbides in an amount of 0.1 to 5 weight percent. Furthermore, a cemented carbide substrate may comprise nitrogen.

[0010] A cutting tool substrate may include one or more cutting edges formed at the junction between a rake face and flank surface(s) of the substrate. Fig. 1 illustrates a cutting insert substrate according to an embodiment described herein. As in Fig.As illustrated in Figure 1, the substrate (10) has cutting edges (12) formed at the junctions between the substrate chip surface (14) and flank surfaces (16). The substrate (10) further includes an opening (18) for securing the substrate (10) to a tool holder.

[0011] As described herein, a coating adhered to the substrate includes a composite refractory layer having a matrix phase comprising alumina (Al2O3) and at least one particulate phase within the matrix phase, wherein the particulate phase comprises nano- to submicron-sized particles formed from at least one of an oxycarbide and oxycarbonitride of one or more metals selected from the group consisting of aluminum and Group IVB metals. The groups of the Periodic Table of Elements described herein are identified according to the CAS designation, with Group IVB including titanium, zirconium, and hafnium. Particles of the particulate phase can generally have a diameter of 5 nm to 800 nm and have a crystalline structure. In some embodiments, the particulate phase particles have a diameter from Table I. Table 1 - Crystalline particle diameter (nm) ≤ 100 50-500 25-300 1-100

[0012] Particles of the particulate phase may have a generally spherical, elliptical, or rod-like shape. In some embodiments, the particles may have a rice-like or irregular shape. Furthermore, the particle shape may be substantially uniform throughout the refractory layer. Alternatively, the particle shape may vary within the refractory layer.

[0013] Particles of the particulate phase can have any desired distribution within the alumina matrix phase, including substantially uniform as well as heterogeneous distributions. In some embodiments, the particles can have regular spacing or irregular spacing within the alumina matrix phase. For example, in some embodiments, the regular spacing of the particles can range from 20 nm to 2 µm. Furthermore, particles can also have a patterned distribution within the alumina matrix phase.

[0014] The composite identity of nano- to submicron-sized particles in the particle phase can be uniform or essentially uniform throughout the refractory layer. Alternatively, the composite identity of the particles can vary throughout the refractory layer. For example, the Group IVB metal(s) of the oxycarbide and / or oxycarbonitride particles can vary along the thickness of the refractory layer. When they vary, the Group IVB metals can represent any desired pattern in the particle phase, such as an alternating or regular distribution along the thickness of the refractory layer. The variation of the Group IVB metals can also be random throughout the refractory layer. Furthermore, the non-metallic component of the particles can vary along the thickness of the refractory layer.In some embodiments, the non-metallic oxycarbide and oxycarbonitride components can have any desired pattern, including an alternating or periodic distribution along the thickness of the refractory layer. The non-metallic component can also have a random distribution. The ability of the particulate phase to independently vary metallic (Ti, Zr, Hf, Al) components and non-metallic (OC, OCN) components along the thickness of the refractory layer allows for design freedom that matches the wear applications and environments.

[0015] As described herein, the composite refractory layer may further comprise titanium-containing nanoscale band structures. In some embodiments, such band structures are crystalline and have at least one dimension ranging from 1 nm to 100 nm. The nanoscale band structures may be dispersed throughout the alumina matrix. The distribution of the nanoscale band structures may be periodic, aperiodic, or patterned within the composite refractory layer. Furthermore, the nanoscale band structures within the composite refractory layer may have a uniform composition or a diverse composition. Thus, in some embodiments, the nanoscale band structures are formed from at least one of titanium oxycarbide, titanium oxycarbonitride, titanium aluminum oxycarbide, and titanium aluminum oxycarbonitride.Together with the particle phase in the nano- to submicron range, the nano-scale band structures provide reinforcement to the alumina matrix, thereby imparting one or more properties of the composite refractory layer such as strength, hardness, toughness and friction behavior.

[0016] Depending on the CVD conditions, the alumina matrix phase can be α-alumina, κ-alumina, or mixtures (α / κ) thereof. In some embodiments, the reinforcing nanoscale particle phase and / or ribbon structures terminate alumina grain growth, resulting in refinement of the alumina matrix grains. Thus, the termination of grain growth can limit the alumina grain size in one or more dimensions to the submicron or nanoscale. In some embodiments, the matrix alumina grains have a diameter selected from Table II. Table II - Alumina grain diameter (nm) 50-800 75-500 100-300

[0017] Furthermore, grains of the alumina matrix may have a columnar morphology. In some embodiments, the alumina matrix phase further comprises a Group IVB metal dopant. Such a dopant may be incorporated into the alumina grains.

[0018] Fig. 2 is an SEM image of a portion of a composite refractory layer according to some embodiments described herein. As in Fig.2, the nano- to submicron-sized particles (white) are uniformly or substantially uniformly dispersed throughout the alumina matrix (grey), wherein the particles are formed from at least one of an oxycarbide and oxycarbonitride of one or more metals selected from the group consisting of aluminum and Group IVB metals. A more detailed examination, which is shown by the STEM image of the Fig. 3, results in the presence of nanoscale band structures in addition to the nanoparticles in the alumina matrix.

[0019] Regarding the aluminum oxide matrix, Fig. 4(a) a bright-light TEM image of a section of a composite refractory layer showing the crystalline grain structure. The insert from Fig. Figure 4(a) is a SAED pattern showing the polycrystalline morphology of the composite refractory layer. Fig.4(b) is the corresponding dark field TEM image of the composite refractory layer of Fig. 4(a), which further shows nanoscale aluminum oxide grains. The aluminum oxide grain morphology is shown in the TEM image from Fig. 4(c). The single alumina grain from Fig. 4(c) is columnar with a width of about 120 nm and a height of 240 nm. Fig. Figure 4(d) is a convergent beam electron diffraction (CBED) of the columnar grain of the Fig. 4(c).

[0020] The Fig. 5(a) to (d) further show composite parameters of several structural features of a composite refractory layer described herein. Fig. Figure 5(a) is an EDS line profile of a section of a nanocomposite refractory layer. As shown in Fig. As provided in Figure 5(a), the titanium content of the refractory layer is appropriate for sites of reinforcing particle phase and band structures at the nanoscale. Fig. 5(b) and Fig.5(d) further confirm the presence of titanium at these reinforcement sites, whereas Fig. 5(c) shows the alumina composition of the matrix phase.

[0021] Fig. 6(a) is a bright field TEM image of a portion of a composite refractory layer according to some embodiments described herein. Fig. Figure 6(b) is a STEM image of a section of a composite refractory layer according to some of the embodiments described herein. Furthermore, the presence and 2-dimensional morphologies of nanoscale band structures in the alumina matrix are revealed.

[0022] The composite refractory layer having the structure and composition described herein may have any thickness that is not inconsistent with the objectives of the present invention. For example, the composite refractory layer has a thickness of 0.05 µm to 20 µm. In some embodiments, the composite refractory layer has a thickness selected from Table III. Table III - Thickness of the composite refractory layer (µm) 0,5-15 1-10 2-8

[0023] The composite refractory layer can be deposited directly onto the surface of the substrate. Alternatively, a coating described herein can further comprise one or more layers between the composite refractory layer and the substrate. The inner layer(s), in some embodiments, comprise one or more metallic elements selected from the group consisting of aluminum and metallic elements of Groups IVB, VB, and VIB of the Periodic Table, and one or more non-metallic elements selected from Groups IIIA, IVA, VA, and VIA of the Periodic Table. In some embodiments, one or more inner layers between the substrate and the refractory layer comprise a carbide, nitride, carbonitride, oxycarbonitride, oxide, or boride of one or more metallic elements selected from the group consisting of aluminum and metallic elements of Groups IVB, VB, and VIB of the Periodic Table.

[0024] For example, one or more inner layers are selected from the group consisting of titanium nitride, titanium carbonitride, titanium oxycarbonitride, titanium carbide, zirconium nitride, zirconium carbonitride, hafnium nitride, and hafnium carbonitride. Furthermore, a layer of titanium oxycarbonitride can be used as a bonding layer for the refractory layer and the inner layers of the coating. The inner layer(s) of the coating can have any thickness that is not incompatible with the objectives of the present invention. In some embodiments, a single inner layer can have a thickness of at least 1.5 µm. Alternatively, a plurality of inner layers together can achieve a thickness of at least 1.5 µm.

[0025] The composite refractory layer may be the outermost layer of the coating. Alternatively, a coating described herein may comprise one or more outer layers over the refractory layer. The outer layer(s) may comprise one or more metallic elements selected from the group consisting of aluminum and metallic elements of Groups IVB, VB, and VIB of the Periodic Table, and one or more non-metallic elements selected from Groups IIIA, IVA, VA, and VIA of the Periodic Table. The outer layer(s) over the refractory layer may comprise a carbide, nitride, carbonitride, oxycarbonitride, oxide, or boride of one or more metallic elements selected from the group consisting of aluminum and metallic elements of Groups IVB, VB, and VIB of the Periodic Table.For example, one or more outer layers are selected from the group consisting of titanium nitride, titanium carbonitride, titanium oxycarbonitride, titanium carbide, zirconium nitride, zirconium carbonitride, hafnium nitride, hafnium carbonitride and aluminum oxide and mixtures thereof.

[0026] The outer layers of coatings described herein may have any thickness that is not inconsistent with the objectives of the present invention. In some embodiments, an outer layer of a coating may have a thickness in the range of 0.2 µm to 5 µm.

[0027] Coatings described herein may be subjected to post-coating treatments. For example, coatings may be blasted with various wet and / or dry particle compositions. Post-coating blasting may be performed in any manner. In some embodiments, post-coating blasting includes shot peening or pressure blasting. Pressure blasting may be performed in a variety of ways, including compressed air blasting, wet compressed air blasting, pressurized liquid blasting, wet abrasive blasting, and vapor blasting. Wet blasting is performed, for example, using a slurry of inorganic and / or ceramic particles such as alumina and water. The alumina particle slurry may be projected onto a surface of the coated cutter body using compressed air so that it impinges on the surface of the coating.The aluminum oxide particles can generally range in size from approximately 20 µm to approximately 100 µm.

[0028] Blasting parameters include pressure, angle of impact, distance from the part surface, and duration. In some embodiments, the angle of impact may range from about 10 degrees to about 90 degrees, meaning the particles impact the coating surface at an angle ranging from about 10 degrees to about 90 degrees. Suitable pressure may range from 0.2 to 0.4 MPa (30 to 55 pounds per square inch (psi)) at a distance from the coated surface of 2.5 to 15 cm (1 to 6 inches). Furthermore, the duration of blasting may generally range from 1 to 10 seconds or longer. Blasting may generally occur over the surface area of ​​the coating, or it may occur at selected locations, such as a workpiece contact area of ​​the cutting tool. A workpiece contact area may be a honed region of the cutting tool.

[0029] In other embodiments, a coating is subjected to a polishing treatment after coating. Polishing can be performed using a paste with a suitable diamond or ceramic abrasive grain size. In some embodiments, the grain size of the paste is in the range of 1 µm to 10 µm. In one embodiment, a diamond abrasive grain paste of 5-10 µm is used to polish the coating. Furthermore, the abrasive grain paste can be applied to the CVD coating by any device, such as brushes, that is not incompatible with the objectives of the present invention. In one embodiment, for example, a flat brush is used to apply abrasive paste to the CVD coating in a workpiece contact area of ​​the cutting tool.

[0030] A coating described herein may be blasted or polished for a period of time sufficient to achieve a desired surface roughness (R a) and / or other parameters, such as reducing tensile stress in the coating. In some embodiments, a coating that has undergone a post-coating treatment has a surface roughness (R a ) on. Table IV - Surface roughness (Ra) after coating treatment Surface roughness of the coating (R a ) - nm ≤ 500 ≤ 250 < 200 10-250 50-175 25-150

[0031] The surface roughness of the coating can be determined by optical profilometry using WYKO® NT series optical profilometers, commercially available from Veeco Instruments, Inc., located in Plainview, New York.

[0032] Furthermore, in some embodiments, a coating post-treatment does not remove one or more outer layers of the coating. For example, in some embodiments, a coating post-treatment does not remove an outer layer of TiN, TiCN, and / or TiOCN. Alternatively, a coating post-treatment may remove or partially remove one or more outer layers, such as TiN, TiCN, and / or TiOCN.

[0033] A coating described herein comprising a composite refractory layer with an alumina matrix phase and at least one particulate phase therein may have a nanohardness of at least 25 GPa. In some embodiments, the coating has a nanohardness of 30 GPa to 40 GPa. The nanohardness of the coating may be in the as-deposited state. Alternatively, the nanohardness may represent a blasted or polished state of the coating. The coating nanohardness values ​​reported herein were determined according to ISO 14577 by nano-penetration testing using a Vickers indenter and a Fischerscope HM2000. The penetration depth was set to 0.2 µm.

[0034] In addition to hardness, a coating described herein that includes a composite refractory layer may exhibit nanohardness up to a Young's modulus ratio (H / E) greater than 0.05 or greater than 0.07. In some embodiments, the H / E ratio is in the range of 0.07 to 0.15.

[0035] As described herein, the nanocomposite refractory layer is deposited by CVD. The alumina matrix can be deposited from a gaseous mixture of AlCl3, H2, CO2, HCl, and optionally H2S. General CVD processing parameters for deposition of the alumina matrix are provided in Table V. Table V - Alumina matrix CVD processing parameters Process step H2 Vol.-% AlCl3 vol% CO2 Vol.-% CO vol% H2S Vol.-% HCl Vol.-% Temperature °C Pressure Pa (mbar) Time min. Al2O3 rest 1-5 0,5-5 - 0,05-0,5 0,05-5 950-1050 5000-12000 (50-120) 10-500

[0036] The nano- to submicron particles of the particulate phase are deposited onto alumina grains by pulsed introduction into the reactor of a gaseous mixture containing reactants suitable for particle formation. Importantly, each deposition of nano- to submicron particles can be independent of any previous particle deposition. For this reason, gaseous reactants for particulate phase deposition can vary over the duration of the refractory layer thickness. In some embodiments, the gaseous reactant mixture for particulate phase deposition includes H2, N2 (optional), HCl (optional), CH4, CO, AlCl3 (optional), and reactants containing Group IVB metal. In some embodiments, the reactant is metal chloride, such as MCl4, where M is a Group IVB metal. General CVD processing parameters for particulate phase deposition are provided in Table VI. Table VI - CVD processing parameters for particle phase deposition Process step H2 Vol.-% N2 vol% MCl4* Vol% CH4 Vol.-% AlCl3 vol% CO vol% HCl Vol.-% Temperature °C Pressure Pa (mbar) Time min. TiOxCyNz reinforcement* rest Opt. 1-5 1-5 Opt. 0,05-1 Opt. 950-1050 5000-12000 (50-120) 2-200 * M = Group IVB metal

[0037] Deposition of the particulate phase may, in some embodiments, terminate alumina grain growth. In such embodiments, the alumina grains are re-nucleated and grown by reintroducing the reactant gas mixture of Table V. The termination and re-nucleation of alumina may refine alumina grains to the submicron or nanoscale.

[0038] The refractory layer can be deposited directly on the substrate surface. Alternatively, multiple inner layers of the coating can be located between the substrate and the refractory layer. General CVD deposition parameters for various inner layers are provided in Table VII. Table VII - CVD parameters for the deposition of inner layers Composition of the base layer Gas mixture Temperature °C Pressure Pa (mbar) Duration min. TiN H2, N2, TiCl4 800-900 6000-10000 (60-100) 10-90 MT-TiCN H2, N2, TiCl4, CH3CN 750-900 6500-1000 (65-100) 50-400 HT-TiCN H2, N2, TiCl4, CH4 900-1050 6000-16000 (60-160) 30-200 TiOCN H2, N2, TiCl4, CH4, CO 900-1050 20000-55000 (200-550) 30-70

[0039] The aforementioned general CVD parameters for deposition of inner layers can, in some embodiments, be applied to the deposition of one or more outer layers over the refractory layer.

[0040] These and other embodiments are further illustrated in the following non-limiting examples. Example 1 - Coated cutting tools

[0041] Cutting tools described herein were manufactured by placing cemented tungsten carbide (WC-Co) cutting insert substrates [ANSI standard geometry CNMG432RN] into a hot-wall axial-flow CVD reactor. The cutting inserts comprised 6 wt% cobalt binder, with the residual WC grains ranging in size from 1 to 5 µm. A coating comprising a composite refractory layer with a matrix phase comprising alumina and a particulate phase comprising nano- to submicron-sized crystalline particles formed from TiOCN was deposited on the cutting inserts according to Tables VIII and IX. The composite refractory layer also comprised titanium-containing nanoscale bands. The particulate phase and nanoscale band reinforcements were introduced into the alumina matrix by pulsing cycles, such as 48 and 96 pulse cycles, as shown in Table VIII.An outer layer of TiN was deposited over the nanocomposite refractory layer to complete the coating. Alternatively, if desired, an outer layer of TiOCN can be deposited over the nanocomposite refractory layer to complete the coating. Table VIII - CVD deposition of the coating Process step H2 Vol.-% N2 vol% TiCl4 vol% CH3CN Vol.-% CH4 Vol.-% AlCl3 vol% CO2 Vol.-% CO vol% HCl Vol.-% H2S Vol.-% TiN rest 18,40 0,95 - - - - - - MT-TiCN rest 27,8 1,31 0,001 - - - - 1,40 HT-TiCN rest 16,69 0,76 - 3,70 - - - - - TiOCN rest 17,50 1,08 - 2,52 - - 1,10 1,10 Al2O3 rest - - - - 4,84 2,42 - 3,00 0,10 TiOxCyNz reinforcement* rest 11,40 3,65 - 1,94 - - 0,49 Opt. - TiN (outer layer) rest 25,70 0,76 Opt. TiOCN** (outer layer) rest 38,00 0,99 - 2,6 - - 1,12 Opt. - * Periodic introduction onto the aluminum oxide layer to form a TiOxCyNz reinforcement (48 and 96 introductions) ** Alternative outer layer Table IX - CVD deposition steps Process step Temperature °C Pressure Pa (mbar) Time min. TiN 850-960 6000-9000 (60-90) 10-90 MT-TiCN 900-940 7000-1000 (70-100) 50-400 HT-TiCN 900-1050 6000-15000 (60-150) 30-200 TiOCN 950-1050 20000-5000 (200-500) 30-70 Al2O3 950-1050 5000-12000 (50-120) 10-500 TiOxCyNz reinforcement* 950-1050 5000-12000 (50-120) 2-200 TiN (outer layer) 850-960 6000-9000 (60-90) 10-90 TiOCN (outer layer)** 950-1050 20000-5000 (200-500) 30-180 * Periodic introduction onto the aluminum oxide layer to form the TiOxCyNz reinforcement. ** Alternative outer layer

[0042] The resulting coatings exhibited properties provided in Tables X and XI. Table X - Properties of 48-pulse cycle coating (Example 1a) Coating layers Thickness (µm) TiN 0,2 MT-TiCN 11,8 HT-TiCN / TiOCN 1,0 [Al2O3-TiOxCyNZ] 48 6,8 TiN 1,6 Table XI - Properties of 96-pulse cycle coating (Example 1b) Coating layers Thickness (µm) TiN 0,3 MT-TiCN 8,8 HT-TiCN / TiOCN 0,9 [Al2O3-TiOxCyNZ] 96 7,2 TiOCN 1,5 Example 2 - Coating hardness

[0043] The coated cutting tool from Example 1a was subjected to a nanohardness test. The nanohardness was also determined for a comparable cutting insert of identical ANSI geometry with a CVD coating as listed in Table XII (Comparative Example 1). The nanohardness was determined according to ISO 14577 using a nano-penetrant test with a Vickers indenter and a Fischerscope HM2000. The penetration depth was set to 0.2 µm. Table XII - Properties of the CVD coating of Comparative Example 1 Coating layers Thickness (µm) TiN 0,5 MT-TiCN 10,4 HT-TiCN 1,0 Al2O3 8,4 TiN 1,6

[0044] Example 1a and Comparative Example 1 were in the as-deposited condition. The results of this test are shown in Table XIII. Table XIII - Nanohardness and H / E results Cutting insert Nanohardness (GPa) H / E Example 1a 34,2 0,09 Comparison example 1 27,9 0,07 Example 3 - Metal cutting test

[0045] Coated cutting inserts from Examples 1a, 1b, and Comparative Example 1 were subjected to a continuous turning test according to the following parameters. The coatings from Examples 1a and 1b were subjected to post-coating treatment as shown in Table XIV. Table XIV - Coated inserts for turning testing Cutting insert Coating architecture Treatment after coating 1 Example 1a Wet blasting at 0.3 MPa (40 psi) for 4 seconds to completely remove the outer layer 2 Example 1a Wet blasting at 0.3 MPa (40 psi) for 3 seconds 3 Example 1b Wet blasting at 0.3 MPa (40 psi) for 3 seconds 4 Comparison example 1 Wet blasting at 0.3 MPa (40 psi) for 4 seconds to completely remove the outer layer

[0046] For the turning test, two samples each of cutting insert 1 to 4 were tested to generate repetition 1, repetition 2 and average cutting life. Rotation parameters Workpiece: steel, quality 1045 Speed: 305 m / m (1000 sfm) Feed rate: 0.03 mmpr (0.012 ipr) Cutting depth: 0.2 cm (0.08 inches) Clearance angle: -5° Coolant surge

[0047] The end of life was determined by one or more fault conditions of: uniform wear (UW) of 0.03 cm (0.012 inches) maximum wear (Max Wear, MW) of 0.03 cm (0.012 inches) Nose wear (NW) of 0.03 cm (0.012 inches) Depth of cut notch wear (DOCN) of 0.03 cm (0.012 in) Trailing edge wear (TW) of 0.03 cm (0.012 inches)

[0048] The results of the continuous rotation test are shown in Table XV. Table XV - Results of the continuous rotation test Coated cutting insert CVD coating architecture Repetition 1, lifetime min. Repetition 2, lifetime min. Average cutting life Min. Relative tool life vs. comparison example 1 1 Example 1a 21,8 19,0 20,4 109 % 2 Example 1a 21,8 21,0 21,4 116 % 3 Example 1b 18,8 18,8 18,8 101 % 4 Comparison example 1 19,6 17,8 18,7 -

[0049] As shown in Table XV, the cutting insert using the CVD coating architectures described herein exceeds the performance of the industry standard aluminum oxide coating of Comparative Example 1.

Claims

[1] Coated article comprising: a substrate; and a substrate-adherent coating deposited by chemical vapor deposition, CVD, the coating comprising a refractory layer having a matrix phase containing α-alumina, κ-alumina, or mixtures thereof, and at least one particulate phase dispersed within the matrix phase, the particulate phase comprising nano- to submicron-sized particles formed from at least one oxycarbide and / or oxycarbonitride of one or more metals selected from the group consisting of aluminum and Group IVB metals. [2] The coated article of claim 1, wherein the refractory layer further contains nanoscale titanium-containing band structures within the matrix phase. [3] The coated article according to claim 1 or 2, wherein the particles have a size of 5 nm to 800 nm. [4] A coated article according to any one of claims 1 to 3, wherein the particles are crystalline. [5] The coated article of claim 2, wherein the titanium-containing nanoscale ribbon structures have at least one dimension in the range of 1 nm to 100 nm. [6] The coated article according to claim 2 or 5, wherein the titanium-containing ribbon structures have a 2-dimensional structure. [7] A coated article according to any one of the preceding claims, wherein the particles have regular or patterned spacing in the matrix phase. [8] The coated article of claim 7, wherein the regular spacing is in the range of 20 nm to 2 µm. [9] A coated article according to any one of claims 1 to 6, wherein the particles are uniformly distributed in the matrix phase. [10] A coated article according to any one of the preceding claims, wherein alumina grains of the matrix phase are columnar. [11] A coated article according to any one of the preceding claims, wherein the alumina of the matrix phase further comprises a Group IVB metal dopant. [12] A coated article according to any one of the preceding claims, wherein the composition of the particles varies with the thickness of the refractory layer. [13] A coated article according to any one of the preceding claims, wherein the Group IVB metal is titanium. [14] A coated article according to any one of the preceding claims, wherein the CVD coating has a nanohardness of at least 25 GPa. [15] The coated article according to claim 14, wherein the CVD coating has a nanohardness of 30 to 40 GPa. [16] A coated article according to any one of the preceding claims, wherein the CVD coating has a nanohardness to Young's modulus ratio, H / E, greater than 0.

05. [17] The coated article of claim 16, wherein the H / E ratio is greater than 0.

07. [18] A coated article according to any one of the preceding claims, wherein the refractory layer has a thickness of 0.05 µm to 20 µm. [19] A coated article according to any one of the preceding claims, further comprising one or more inner layers between the refractory layer and the substrate, wherein an inner layer comprises one or more metallic elements selected from the group consisting of aluminum and metallic elements of groups IVB, VB and VIB of the Periodic Table and one or more non-metallic elements of groups IIIA, IVA, VA and VIA of the Periodic Table. [20] A coated article according to any one of the preceding claims, further comprising one or more outer layers over the refractory layer and the substrate, wherein an outer layer comprises one or more metallic elements selected from the group consisting of aluminum and metallic elements of Groups IVB, VB and VIB of the Periodic Table and one or more non-metallic elements of Groups IIIA, IVA, VA and VIA of the Periodic Table. [21] A coated article according to any one of the preceding claims, wherein the substrate is cemented carbide, cermet, steel or polycrystalline cubic boron nitride.

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