Polycrystalline cubic boron nitride

Abstract

The present invention relates to a polycrystalline cubic boron nitride (PCBN) sintered body (1, 2), its manufacturing method and its use. The polycrystalline cubic boron nitride (PCBN) sintered body (1, 2) comprises between 40 and 85% by volume of cubic boron nitride (cBN) particles and between 15 and 60% by volume of a binder phase, said binder phase comprising at least one metal oxide and at least one metal nitride. The at least one metal oxide comprises between 20 and 100 vol. % zirconium oxide (ZrO2) and up to 80 vol. % alumina (Al2O3), calculated as a volume percentage of the total content of metal oxides of the binder phase; the at least one metal nitride comprises aluminum nitride (AlN) and at least one metal nitride selected from the group consisting of vanadium nitride (VN), niobium nitride (NbN) and hafnium nitride (HfN), the content of the at least one metal nitride selected from the group consisting of vanadium nitride (VN), niobium nitride (NbN) and hafnium nitride (HfN) being at least 10 vol. % of the total binder phase; and the content of the at least one metal oxide is at least 10 vol. % of the total binder phase.

Description

[Technical Field]

[0001] This disclosure relates to a polycrystalline cubic boron nitride (PCBN) body, a method for producing the polycrystalline cubic boron nitride (PCBN) body, and the use of the same. [Background technology]

[0002] Current tooling solutions for difficult-to-machine materials such as heat-resistant nickel-based or cobalt-based superalloys (HRSA) are typically limited to the use of coated cemented carbide tools operated at relatively low cutting speeds. This is the current standard practice in the aerospace manufacturing industry.

[0003] The main wear modes observed when machining HRSA alloys are crater wear, relief wear / nose wear, notching, cracking, chipping, plastic deformation, and catastrophic chipping. Crater wear often belongs to the diffusion wear or dissolution wear mechanism, where a smooth wear surface is observed. In addition, wear is accompanied by the progression of relief wear due to the softening of the tool material at high cutting temperatures. The relief portion of the cutting tool is exposed to contact motion with the workpiece and relief wear, leading to a lack of surface quality of the workpiece, inaccuracy of the cutting process, and increased friction as cutting progresses. Cutting tools made of polycrystalline cubic boron nitride (PCBN) are highly valued for machining HRSA alloys because they can maintain high hardness at high temperatures.

[0004] With the increasing demand for increased productivity, alternative solutions to coated cemented carbide have emerged in aircraft engine manufacturing, for example, by increasing cutting speed or achieving high metal removal rates, and can be used for semi-finishing applications in high-speed machining of HRSA alloys. An example of an alternative solution currently in use is PCBN cutting tool with a titanium carbide (TiC) or titanium carbide nitride (TiCN) based binder.

[0005] PCBN materials still have higher costs compared to cemented carbide materials, and to improve cost-effectiveness, they need to demonstrate even higher productivity than conventional PCBN solutions using TiC or TiCN as a binder.

[0006] Patent application WO2011098556A1 discloses an example of a PCBN material having a conventional binder phase containing TiC or TiCN. Deviating from conventional PCBN compositions, patent application EP3239116A1 shows a PCBN sintered body having 40 and 85 volume percent (vol%) of cBN and 15 and 60 volume percent of the binder phase. The binder phase mainly consists of aluminum (Al) compounds such as Al2O3 and AlN, with additives such as zirconium oxide (Zr) compounds such as zirconium oxide (ZrO), and zirconium dioxide (ZrO2) in an amount of up to 10 volume percent of the total cubic boron nitride sintered body.

[0007] To meet the above requirements, there is a demand for new PCBN materials that can be used for cutting tool bodies and possess advanced properties that improve tool life during machining operations. If better relief wear resistance and / or boundary wear resistance can be obtained, longer tool life can be achieved for several machining applications and operations. [Overview of the project]

[0008] The objective of the present invention is to provide a PCBN sintered body with improved machining performance.

[0009] This objective is achieved by the PCBN body specified in claim 1 and the method described in claim 14.

[0010] This disclosure provides a polycrystalline cubic boron nitride (PCBN) sintered body comprising cubic boron nitride (cBN) particles between 40 and 85 volume percent and a binder phase between 15 and 60 volume percent, wherein the binder phase comprises at least one metal oxide and at least one metal nitride, the at least one metal oxide comprising zirconium oxide (ZrO2) between 20 and 100 volume percent and alumina (Al2O3) up to 80 volume percent, calculated as a volume percentage of the total metal oxide content of the binder, and the at least one metal nitride comprising aluminum nitride (AlN) and at least one metal nitride selected from the group consisting of vanadium nitride (VN), niobium nitride (NbN) and hafnium nitride (HfN), the content of the metal nitride being at least 10 volume percent of the binder phase. This results in a PCBN body with improved machining performance.

[0011] The disclosure also relates to a polycrystalline cubic boron nitride (PCBN) sintered body comprising cubic boron nitride (cBN) particles between 40 and 85 volume percent and a binder phase between 15 and 60 volume percent, wherein the binder phase comprises at least one metal oxide and at least one metal nitride, wherein the at least one metal oxide comprises zirconium oxide (ZrO2) between 20 and 100 volume percent and alumina (Al2O3) up to 80 volume percent, calculated as a volume percentage of the total metal oxide content of the binder, and the at least one metal nitride is aluminum nitride (AlN), as well as vanadium nitride (VN) and niobium nitride. The present invention provides a polycrystalline cubic boron nitride (PCBN) sintered body comprising at least one metal nitride selected from the group consisting of vanadium nitride (VN), niobium nitride (NbN), and hafnium nitride (HfN), wherein the content of the metal nitride selected from at least one of vanadium nitride (VN), niobium nitride (NbN), and hafnium nitride (HfN) constitutes at least 10 volume percent of the total binder phase, and the at least one metal oxide constitutes at least 10 volume percent, preferably, for example, at least 20 volume percent, at least 30 volume percent, at least 40 volume percent, at least 50 volume percent, or at least 60 volume percent of the total binder phase.

[0012] According to one embodiment, the content of AlN in the polycrystalline cubic boron nitride (PCBN) sintered body is in the range of 1 to 10 volume %, for example 1 to 7 volume %, for example 2 to 6 volume % or 3 to 5 volume % of the total binder phase. According to some aspects, the binder phase of the PCBN body further comprises at least one metal oxynitride which is a reaction product of one of at least one metal oxide and one of at least one metal nitride. In other words, when the binder phase comprises at least one metal oxynitride, the at least one metal oxynitride is a reaction product of a metal oxide selected from the group consisting of ZrO2 and Al2O3 and a metal nitride selected from the group consisting of VN, NbN and HfN. Tests have shown that the average tool life of a PCBN body having a binder phase according to the compositions disclosed above is improved compared to prior art solutions using other types of binder phase compositions. When the binder phase of the PCBN body has a composition according to the compositions disclosed above and the same cutting parameters are used, higher flank wear resistance and higher boundary wear resistance are obtained during machining compared to prior art solutions.

[0013] According to some aspects, the PCBN body comprises cBN particles between 50 and 75 volume %, preferably between 60 and 75 volume %, and even more preferably between 60 and 70 volume %.

[0014] According to some aspects, the PCBN body comprises a binder phase between 25 and 50 volume %, preferably between 25 and 40 volume %, and even more preferably between 30 and 40 volume %.

[0015] According to some aspects, the content of cBN particles and binder phase in the PCBN body is up to 100 volume % of the PCBN body.

[0016] According to some aspects, the content of metal oxide, metal nitride and metal oxynitride in the binder phase is up to 100 volume % of the binder phase.

[0017] According to some embodiments, the binder phase includes at least one oxynitride selected from the group consisting of zirconium oxynitride (Zr(O,N)), zirconium vanadium oxynitride ((Zr,V)ON), zirconium niobium oxynitride ((Zr,Nb)ON), and zirconium hafnium oxynitride ((Zr,Hf)ON).

[0018] According to some embodiments, the binder phase includes at least one oxynitride selected from the group consisting of aluminum oxynitride (Al(O,N)), aluminum vanadium oxynitride ((Al,V)ON), aluminum niobium oxynitride ((Al,Nb)ON), and aluminum hafnium oxynitride ((Al,Hf)ON).

[0019] According to some embodiments, the binder phase consists of at least one metal nitride selected from the group consisting of ZrO2, Al2O3, AlN, and VN, NbN, and HfN.

[0020] According to some embodiments, the metal nitrides selected from the group consisting of VN, NbN, and HfN constitute up to 60 vol% of the total binder, such as up to 50 vol% of the total binder phase, such as up to 40 vol% or up to 30 vol% or up to 20 vol% of the total binder phase. By having up to 60 vol% or up to 50 vol% or up to 40 vol% or up to 30 vol% or up to 20 vol% of the total binder phase that is a metal nitride from the group consisting of VN, NbN, and HfN, the mechanical properties of the material and the chipping resistance of the cutting edge are improved compared to a binder containing only a metal oxide phase.

[0021] According to some embodiments, the metal nitrides selected from the group consisting of VN, NbN, and HfN constitute between 10 and 50 vol% of the total binder phase. By having the total binder phase that is a metal nitride from the group consisting of VN, NbN, and HfN between 10 and 50 vol%, the mechanical properties of the material and the chipping resistance of the cutting edge are improved compared to a binder containing only a metal oxide phase.

[0022] According to one embodiment, a metal nitride selected from the group consisting of VN, NbN, and HfN constitutes at least 20% by volume, at least 30% by volume, or at least 40% by volume of the total binder phase.

[0023] According to one embodiment, the aluminum nitride content is as further specified herein, but the aluminum nitride together with the at least one metal oxide constitutes a maximum of 90% by volume, or a maximum of 80% by volume, or a maximum of 70% by volume, or a maximum of 60% by volume, or a maximum of 50% by volume, or a maximum of 40% by volume, or a maximum of 30% by volume, or a maximum of 20% by volume, of the total binder phase.

[0024] According to some embodiments, the binder phase comprises ZrO2, Al2O3, and at least one metal nitride selected from the group consisting of AlN, VN, NbN, and HfN, as well as at least one oxynitride selected from the group consisting of Zr(O,N), (Zr,V)ON, (Zr,Nb)ON, (Zr,Hf)ON, Al(O,N), (Al,V)ON, (Al,Nb)ON, and (Al,Hf)ON. The tests showed that the average tool life of PCBN bodies containing a binder phase comprising ZrO2, Al2O3, and at least one metal nitride selected from the group consisting of AlN, VN, NbN, and HfN, as well as at least one oxynitride selected from the group consisting of Zr(O,N), (Zr,V)ON, (Zr,Nb)ON, (Zr,Hf)ON, Al(O,N), (Al,V)ON, (Al,Nb)ON, and (Al,Hf)ON, is increased compared to prior art solutions using other types of binder phase compositions.

[0025] According to some embodiments, the oxynitride and metal nitride are between 10 and 50 volume percent of the total binder phase of the PCBN. Preferably, the oxynitride and metal nitride are between 25 and 50 volume percent of the total binder phase of the PCBN.

[0026] According to some embodiments, ZrO2 is between 20 and 90 volume % of the total content of metal oxides in the binder phase. Preferably, ZrO2 is between 50 and 90 volume % of the total content of metal oxides in the binder phase, and even more preferably, ZrO2 is between 70 and 90 volume % of the total content of metal oxides in the binder phase.

[0027] According to some embodiments, Al2O3 is between 5 and 25 volume % of the total binder phase. Preferably, Al2O3 is between 5 and 15 volume % of the total binder phase. According to one embodiment, a further component may be included in the binder phase, such as TiC or other conventionally used components. However, the binder phase preferably consists of metal oxides and metal nitrides as further specified herein.

[0028] According to some embodiments, the PCBN body is backed by a cemented carbide substrate.

[0029] According to some embodiments, the PCBN body is coated with a PVD coating or a CVD coating having a thickness between 0.8 μm and 15 μm.

[0030] According to some embodiments, the PCBN body has a single (Ti x , z1 , 1―x Al x )N z (where 0.1 < x < 0.4, 0.6 < z < 1.2) layer of a first (Ti,Al)-based nitride subcoating, and a (Ti 1―x1―y1 Al x1 Cr y1 )N z1 (where 0.5 < x1 < 0.75, 0.05 < y1 < 0.2, 0.6 < z1 < 1.2) layer, and is coated with a PVD coating including a second (Ti,Al)-based nitride subcoating having a laminated structure. Preferably, the thickness of the first (Ti,Al)-based nitride subcoating is between 0.1 μm and 2 μm. The second (Ti,Al)-based nitride subcoating having a laminated structure is an alternating body of layer A and layer B: A / B / A / B / A / B / ..., (where layer A is (Ti 1―x Al x )Nz and 0.1 < x < 0.4, 0.6 < z < 1.2, and layer B is (Ti 1―x1―y1 Al x1 Cr y1 )N z1 and 0.5 < x1 < 0.75, 0.05 < y1 < 0.2, 0.6 < z1 < 1.2). Preferably, the second (Ti,Al)-based nitride subcoating has a laminated structure with a thickness between 0.5 μm and 10 μm, and the A and B layers of the laminated structure have an average individual layer thickness between 1 nm and 100 nm, preferably between 5 nm and 50 nm, and most preferably between 5 nm and 30 nm.

[0031] According to some embodiments, in the above PCBN body, layer A is (Ti 1―x Al x Me1 p )Na, where 0.3 < x < 0.95, preferably 0.45 < x < 0.75, 0.90 < a < 1.10, preferably 0.96 < a < 1.04, 0 ≤ p < 0.15, Me^{1} is one or more of Zr, Y, V, Nb, Mo, and W, and layer B is (Ti 1―y―z Si y Me2 z )N b where 0.05 < y < 0.25, preferably 0.05 < y < 0.18, 0 ≤ z < 0.4, 0.9 < b < 1.1, preferably 0.96 < b < 1.04, and Me^{2} is one or more of Y, V, Nb, Mo, W, and Al, and is coated with a PVD coating including a columnar and polycrystalline nanolaminated structure of an alternating body of layer A and layer B. The thickness of the above nanolaminated structure is between 0.5 μm and 10 μm, preferably between 0.5 μm and 5 μm, the average column width is between 20 nm and 1000 nm, and the average individual thickness of layer A and layer B is between 1 nm and 50 nm.

[0032] According to some embodiments, the above PCBN body is a cutting tool or a cutting tip of a cutting tool. The above cutting tool is used for machining by chip removal, such as in turning, milling, or drilling operations. Examples of cutting tools are indexable cutting inserts, solid drills, and end mills.

[0033] This disclosure relates to a method for producing a PCBN body according to any of the above embodiments, comprising the following steps: (a) A step of preparing cubic boron nitride (cBN) powder having an average particle size between 0.5 μm and 15 μm, (b) A step of preparing a binder component comprising ZrO2, or a mixture of ZrO2 and Al2O3, at least one metal nitride selected from the group consisting of VN, NbN and HfN constituting at least 10 volume percent of the binder mixture, and metallic aluminum, (c) A step of mixing the above binder components with cBN powder to make a powder mixture, (d) A step of grinding the above powder mixture, (e) A step of forming an unsintered body (green body) of the above powder mixture, (f) A step to ensure sufficient degassing and removal of absorbent species by heat-treating the unsintered body at a temperature exceeding 600°C under reduced pressure, (g) A step of sintering the above unsintered body at a temperature of at least 1200°C and a pressure of at least 4 GPa to form a solid PCBN sintered compact, and then forming a PCBN body. This provides a method that includes [something].

[0034] According to one embodiment, metallic aluminum is added in an amount of 1 to 10% by volume or 1 to 5% by volume of the total amount of added components.

[0035] According to some embodiments, the heat treatment process for the unsintered body is carried out at a temperature of less than 1100°C.

[0036] According to some embodiments, the sintering process of the unsintered body is carried out at a temperature of less than 2000°C.

[0037] According to some embodiments, the manufactured solid PCBN sintered compact is then cut into individual pieces using electrical discharge machining (EDM) or a laser.

[0038] This disclosure provides the use of PCBN bodies in any of the above embodiments for machining nickel-based superalloys and / or cobalt-based superalloys.

[0039] The present invention will be described in more detail hereafter by the description of various embodiments of the present invention and by reference to the accompanying drawings. [Brief explanation of the drawing]

[0040] [Figure 1] This figure shows an example of a solid PCBN. [Figure 2] This figure shows another example of a solid PCBN body using a cemented carbide substrate brazed onto a cemented carbide insert carrier. [Figure 3] This figure shows an optical microscope image of relief wear on a PCBN body according to an embodiment of the present invention. [Figure 4] This figure shows optical microscope images of the escape wear on the PCBN body for the first comparison. [Figure 5] This figure shows optical microscope images of relief wear on a PCBN body for the second comparison. [Figure 6] This figure shows an optical microscope image of boundary wear on a PCBN body according to an embodiment of the present invention. [Figure 7] This figure shows optical microscope images of boundary wear on a PCBN body for the first comparison. [Figure 8] This figure shows optical microscope images of boundary wear on a PCBN body for the second comparison. [Figure 9] This shows a block diagram of an example of a PCBN manufacturing method. [Figure 10] This figure shows SEM images of a PCBN body according to an embodiment of the present invention and XEDS mapping of various elements. [Figure 11] This figure shows the X-ray θ-2θ diffractogram of a PCBN body according to an embodiment of the present invention. [Modes for carrying out the invention]

[0041] Aspects of this disclosure will be described more fully hereafter with reference to the accompanying drawings. However, the devices and methods disclosed herein can be realized in many different forms and should not be construed as being limited to the embodiments described herein. Throughout, similar numbering in the drawings refers to similar elements.

[0042] The technical terms used in this disclosure are for the sole purpose of describing specific aspects of this disclosure and are not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural form unless the context clearly indicates otherwise.

[0043] The term "cutting tool," as used herein, is intended to refer to a cutting tool suitable for metal cutting by chip removal, such as in turning, milling, or drilling. Examples of cutting tools include indexable cutting inserts, solid drills, and end mills.

[0044] Unless otherwise defined, all terms used herein have the same meanings as those commonly understood by those skilled in the art to which this disclosure belongs.

[0045] What cutting tool inserts have in common is that they may be solid bodies, or bodies that include a base with additional material placed on the cutting edge on the rake face, so-called tip-mounted body, or so-called full-face body, so that the cutting tool insert covers the entire rake face.

[0046] Figure 1 shows an example of a PCBN sintered body 1. The PCBN body in Figure 1 is a solid body. The solid PCBN sintered body 1 in Figure 1 may be a cutting tool insert itself, or it may be cut into pieces used as cutting tips for the cutting tool insert. Figure 2 shows an example of a cutting tool insert 3 including a base body 4 and a cutting tip in the form of the PCBN sintered body 2 according to this disclosure. The PCBN body 2 is integrally bonded to the base body 4, which is made of, for example, cemented carbide.

[0047] This disclosure provides PCBN sintered bodies 1 and 2 comprising cubic boron nitride (cBN) particles between 40 and 85 volume percent and a binder phase between 15 and 60 volume percent, wherein the binder phase comprises at least one metal oxide and at least one metal nitride. The at least one metal oxide comprises zirconium oxide (ZrO2) between 20 and 100 volume percent and alumina (Al2O3) up to 80 volume percent, calculated as a volume percentage of the total metal oxide content of the binder. Furthermore, the at least one metal nitride comprises aluminum nitride (AlN) and at least one metal nitride selected from the group consisting of vanadium nitride (VN), niobium nitride (NbN), and hafnium nitride (HfN). The content of the metal nitride is at least 10 volume percent of the binder phase.

[0048] The binder phase of the PCBN sintered body 1 may, for example, contain at least one metal oxynitride which is a reaction product of at least one metal oxide and at least one metal nitride.

[0049] The binder phase may include, for example, at least one oxynitride selected from the group consisting of zirconium oxynitride (Zr(O,N)), zirconium vanadium oxynitride ((Zr,V)ON), zirconium niobium oxynitride ((Zr,Nb)ON), and zirconium hafnium oxynitride ((Zr,Hf)ON).

[0050] Alternatively, or in addition, the above-mentioned oxynitride may include, for example, at least one oxynitride selected from the group consisting of aluminum oxynitride (Al(O,N)), aluminum vanadium oxynitride ((Al,V)ON), aluminum niobium oxynitride ((Al,Nb)ON), and aluminum hafnium oxynitride ((Al,Hf)ON).

[0051] The content of oxynitrides, as well as at least one metal nitride such as vanadium nitride (VN), niobium nitride (NbN), and hafnium nitride (HfN), is, for example, between 10 and 50 volume percent of the total binder phase.

[0052] Figure 9 shows a block diagram of an example of a manufacturing method for PCBN bodies 1 and 2. According to the above example method, the following steps are taken. (a) A step of preparing cubic boron nitride (cBN) powder having an average particle size between 0.5 μm and 15 μm. (b) A step of preparing a metal nitride, which is at least 10 volume percent of the binder mixture, and a metal aluminum binder component, which is at least one metal nitride selected from the group consisting of ZrO2, a mixture of ZrO2 and Al2O3, VN, NbN and HfN. (c) A step of mixing the above binder components with cBN powder to make a powder mixture. (d) A step of grinding the above powder mixture (e) A step of forming an unsintered body of the above powder mixture (f) A step to ensure sufficient degassing and removal of absorbent species by heat-treating the unsintered body at a temperature exceeding 600°C under reduced pressure. (g) A step of sintering the above unsintered body at a temperature of at least 1200°C and a pressure of at least 4 GPa to form a solid PCBN sintered compact, and then forming PCBN bodies (1,2) This will be implemented.

[0053] According to an alternative method example, the following steps are performed to manufacture the PCBN body: — This process involves preparing cubic boron nitride (cBN) powder with an average particle size between 0.5 μm and 15 μm from hexagonal boron nitride (hBN) powder, and this process is carried out at high temperature and high pressure according to standard practices. — A step of preparing a binder mixture comprising a binder component containing metallic aluminum and at least one metal nitride selected from the group consisting of ZrO2, or a mixture of ZrO2 and Al2O3, VN, NbN, and HfN, which constitutes at least 10 volume percent of the binder mixture, and a binder component containing metallic aluminum. - A step of grinding the above binder mixture to make the average particle size of the binder components between 0.5 μm and 10 μm. — A step of mixing the pulverized binder mixture with cBN powder to make a powder mixture, — A step of grinding the above powder mixture in order to reduce the average particle size and ensure accurate mixing and dispersion of the cBN phase in the binder mixture. — A step of forming an unsintered body of the above powder mixture, — A process to ensure sufficient degassing and removal of absorbent species by heat-treating the above unsintered body at a temperature exceeding 600°C under reduced pressure. - A step of sintering an unsintered body at a temperature of at least 1200°C and a pressure of at least 4 GPa to form a solid PCBN sintered compact, and then forming a PCBN body.

[0054] The solid PCBN sintered compact can be cut into individual pieces, for example, using an EDM or laser. The cut pieces forming the PCBN bodies 1 and 2 may be brazed onto a cemented carbide base 4 to form cutting tools, for example, as shown in Figure 2.

[0055] According to an example embodiment, PCBN bodies 1 and 2 are manufactured according to the above method, and the PCBN bodies have approximately 60 volume percent of cBN particles and a binder phase containing ZrO2 (both cubic and tetragonal), Al2O3, AlN, VN, and zirconium oxynitride (Zr(O,N)). Figure 10 shows the XEDS mapping of various elements in the PCBN body, and the XEDS map shows how the cBN crystal grains containing B and N are present in the binder phase containing O, N, Al, V, and Zr. Figure 11 shows the X-ray diffraction (XRD) intensities of cubic BN, ZrO2 (both cubic and tetragonal), Al2O3, AlN, VN, and zirconium oxynitride (Zr(O,N)) in the PCBN body, measured using Cu-Kα radiation and θ-2θ scanning. The diffractometer used was STOE STADI MP. For the analysis of the XRD pattern in Figure 11, the following Crystal Impact Entry (CIE) card was used: Al2O3, CIE-Card: 96-100-0018 AlN, CIE - Card: 96-152-3096 BN, CIE - Card: 96-035-1365 (Cubic crystal) VN, CIE - Card: 96-035-0768 ZrO2, CIE-Card: 95-050-1089 (Tetragonal) ZrO2, CIE-Card: 96-900-7449 (cubic crystal) Zr x (O,N) y CIE-Card: 96-050-1172 [Examples]

[0056] Example 1 A PCBN cutting tool according to an embodiment of the present disclosure having a composition corresponding to Sample 1 in Table 1 was prepared according to the above alternative embodiment example of the manufacturing method. A first comparative PCBN cutting tool having a conventional TiC-bonder with the composition of Sample 2 in Table 1, and a second comparative PCBN cutting tool having a conventional TiCN-bonder with the composition of Sample 3 in Table 1, were prepared under the same powder preparation and sintering conditions as Sample 1.

[0057] We manufactured cutting tools using the ISO RNGN090300 insert shape. Turning was performed longitudinally on an Inconel 718 workpiece material supplied in an aged state and having a hardness of HRC45 using a PCBN cutting tool containing compositions according to samples 1 to 3 (TIFF0007850745000001.tif53170).

[0058] The cutting data used was as follows: 1. Feed rate f = 0.10 mm / revolution, cutting speed v c =300m / min 2. Feed rate f = 0.10 mm / revolution, cutting speed v c =350m / min On the other hand, the depth of cut corresponds to the high-speed finishing conditions in both cases. p The thickness was 0.3 mm. High-pressure localized cooling (HPDC) was applied using an 8% oil-water emulsion as the refrigerant, and the refrigerant pressure was set to 90 bar on the rake face and flank face of the cutting tool.

[0059] cutting speed v c = 3.2 minutes at 300 m / min, and cutting speed v c Relief wear was measured after a helical length of 950 meters, which corresponds to a cutting time of 2.7 minutes at a cutting speed of 350 m / min.

[0060] Recess wear was measured using an Olympus SZX7 optical microscope.

[0061] Relief wear measured at cutting speeds of 300 m / min and 350 m / min is shown in Table 2. TIFF0007850745000002.tif48170 SEM images in Figures 3, 4, and 5 show a cutting speed of 350 m / min, feed rate f = 0.1 mm / revolution, and depth of cut a p This shows the relief wear of samples 1-3 at 0.3 mm after 2.7 minutes.

[0062] From the experimental results and observations related to Example 1, it was concluded that the PCBN cutting tool having the composition according to the present invention demonstrated an improvement of more than 50% in performance compared to conventional TiC-bonding and TiCN-bonding materials.

[0063] Example 2 Turning was performed on an aged Inconel 718 workpiece material with a hardness of HRC45, creating a curved profile with a radius of curvature of R38.5 mm. A PCBN cutting tool having the same composition as in Example 1, i.e., the compositions of Samples 1-3 in Table 1, was used.

[0064] Three different cases of cutting data were used: 1. Feed rate f = 0.10 mm / revolution, cutting speed v c =350m / min 2. Feed rate f = 0.08 mm / revolution, cutting speed v c =420m / min 3. Feed rate f = 0.10 mm / revolution, cutting speed v c =420m / min On the other hand, the depth of cut corresponds to the high-speed finishing conditions in all three cases. p The thickness was 0.3 mm. High-pressure localized cooling (HPDC) was applied using an 8% oil-water emulsion as the refrigerant, and the refrigerant pressure was set to 70 bar on the rake face and flank face of the cutting tool.

[0065] We manufactured cutting tools using the ISO RNGN090300 insert shape.

[0066] Relief wear and boundary wear were measured at time intervals of 0.89 minutes ± 0.11 minutes. The performance test was stopped when either the maximum relief wear exceeded the standard 250 μm or the boundary wear exceeded the standard 1000 μm.

[0067] A PCBN cutting tool with TiC as the main binder phase, i.e., sample 2, was used with a feed rate f = 0.08 mm / revolution and a cutting speed v c Under cutting conditions of 420 m / min, critical boundary wear progressed rapidly, leading to failure due to edge breakage; therefore, it is not included in Table 3, which shows the tool wear of Example 2.

[0068] Relief wear and boundary wear were measured using an Olympus SZX7 optical microscope.

[0069] Table 3 shows the relief wear measured at each cutting time interval when the limit criterion was reached for three different sets of cutting data in which relief wear or boundary wear parameters were used. Table 4 of TIFF0007850745000003.tif70170 shows boundary wear measured with three different sets of cutting data used. TIFF0007850745000004.tif67170 SEM images in Figures 6, 7 and 8 show the cutting speed v c =350m / min, feed rate f=0.1mm / revolution, and depth of cut a p The boundary wear of samples 1, 2, and 3 at 0.3 mm is shown. The boundary wear (μm) and cutting time (minutes) results for the samples in Figures 6, 7, and 8 are also shown in the first column of Table 4. As can be seen from Table 4, sample 1 had the longest cutting time at 7.50 / min, meaning it cut twice as long as sample 2 and 33% longer than sample 3, while at the same time sample 1 still had lower boundary wear than either sample 2 or 3.

[0070] From the experimental results and observations related to Example 2, it was concluded that Sample 1, i.e., the PCBN cutting tool according to the present disclosure, showed an improvement of over 110% in boundary wear criterion compared to conventional TiC-bonding and TiCN-bonding, while demonstrating an improvement of over 31% in performance criterion.

[0071] The present invention is not limited to the disclosed embodiments, but may be modified or altered within the scope of the following claims.

Claims

1. A polycrystalline cubic boron nitride (PCBN) sintered body (1, 2) comprising cubic boron nitride (cBN) particles between 40% and 85% by volume, and a binder phase between 15% and 60% by volume, wherein the binder phase comprises at least one metal oxide and at least one metal nitride. At least one metal oxide is zirconium oxide (ZrO), calculated as a volume percentage of the total metal oxide content in the binder phase. ２ ) between 20% and 90% by volume, and alumina (Al ２ O ３ The binder contains between 5% and 25% by volume, and at least one metal nitride comprises 1% to 10% by volume of aluminum nitride (AlN) relative to the total binder phase, and at least one metal nitride selected from the group consisting of vanadium nitride (VN), niobium nitride (NbN), and hafnium nitride (HfN). The content of at least one metal nitride selected from the group consisting of vanadium nitride (VN), niobium nitride (NbN), and hafnium nitride (HfN) is at least 10% by volume and up to 50% by volume of the total binder phase, and the content of at least one metal oxide is at least 10% by volume of the total binder phase. A polycrystalline cubic boron nitride sintered body characterized by the following features.

2. The PCBN body according to claim 1, wherein the binder phase further comprises at least one metal oxynitride which is a reaction product of at least one metal oxide and at least one metal nitride.

3. The PCBN body according to claim 2, wherein the binder phase comprises at least one oxynitride selected from the group consisting of zirconium oxynitride (Zr(O,N)), zirconium vanadium oxynitride ((Zr,V)ON), zirconium niobium oxynitride ((Zr,Nb)ON), and zirconium hafnium oxynitride ((Zr,Hf)ON).

4. The PCBN body according to claim 2 or 3, wherein the binder phase comprises at least one oxynitride selected from the group consisting of aluminum oxynitride (Al(O,N)), aluminum vanadium oxynitride ((Al,V)ON), aluminum niobium oxynitride ((Al,Nb)ON), and aluminum hafnium oxynitride ((Al,Hf)ON).

5. The binder phase is ZrO ２ Al ２ O ３ The PCBN body according to claim 1, comprising AlN and at least one metal nitride selected from the group consisting of VN, NbN and HfN.

6. The binder phase is ZrO ２ , Al ２ O ３ , at least one metal nitride selected from the group consisting of AlN, VN, NbN and HfN, and at least one oxynitride selected from the group consisting of Zr(O,N), (Zr,V)ON, (Zr,Nb)ON, (Zr,Hf)ON, Al(O,N), (Al,V)ON, (Al,Nb)ON and (Al,Hf)ON, the PCBN body according to claim 1 or 2.

7. The PCBN body according to claim 6, wherein the oxynitride and a metal nitride selected from the group consisting of VN, NbN, and HfN constitute between 10% and 50% by volume of the total binder phase of the PCBN body.

8. The PCBN body according to claim 1 or 2, wherein the PCBN body (1, 2) is backed by a cemented carbide base body (4).

9. The PCBN body according to claim 1 or 2, wherein the PCBN body is coated with a PVD coating or CVD coating having a thickness between 0.8 μm and 15 μm.

10. The PCBN body according to claim 1 or 2, wherein the PCBN body (1, 2) is a cutting tool (3) or a cutting tip (2) of a cutting tool.

11. A method for producing the PCBN body (1, 2) according to claim 1 or 2, comprising the following steps: (a) A step of preparing cubic boron nitride (cBN) powder having an average particle size between 0.5 μm and 15 μm, (b) ZrO ２ , or ZrO ２ and Al ２ O ３ A step of preparing a binder component comprising a mixture of the following, at least one metal nitride selected from the group consisting of VN, NbN, and HfN constituting at least 10 volume percent of the binder mixture, and metallic aluminum, (c) A step of mixing the binder components with cBN powder to make a powder mixture, (d) A step of grinding the powder mixture, (e) A step of forming an unsintered body of the powder mixture, (f) A step of heat-treating the unsintered body at a temperature exceeding 600°C under reduced pressure to ensure sufficient degassing and removal of absorbent species, (g) A step of sintering an unsintered body at a temperature of at least 1200°C and a pressure of at least 4 GPa to form a solid PCBN sintered body, and then forming PCBN bodies (1, 2), A manufacturing method that includes this.

12. Use of the PCBN body according to claim 1 or 2 for machining nickel-based superalloys and / or cobalt-based superalloys.

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