Blade and cutting tool

Abstract

In transmission type X-ray diffraction with respect to a cross section of the boron nitride sintered body perpendicular to the first face (7), let the X-ray intensity of the apex of the 111 diffraction peak of the cubic boron nitride in the direction perpendicular to the first face (7) be IcBN(111)v. Let the X-ray intensity of the apex of the 002 diffraction peak of the compressed boron nitride be IhBN(002)v. Let the X-ray intensity of the apex of the 111 diffraction peak of the cubic boron nitride in the direction parallel to the first face (7) be IcBN(111)h. Let the X-ray intensity of the apex of the 002 diffraction peak of the compressed boron nitride be IhBN(002)h. The compressed boron nitride obtained from these X-ray intensities has a value greater than 0.002 and less than 0.01. The cubic crystal orientation value is greater than 0.5, and the compressed boron nitride orientation value is greater than the cubic crystal orientation value. In addition, the blade (1) of the present application has a coating (20) on at least a portion of the surface of the boron nitride sintered body.

Description

Technical Field

[0001] This invention relates to blades and cutting tools. Background Technology

[0002] Boron nitride sintered bodies possess high hardness. Utilizing this property, boron nitride sintered bodies can be used in materials such as crushing components and tool blades.

[0003] Patent Document 1 describes a boron nitride sintered body containing cubic boron nitride. Additionally, Patent Document 1 describes a cubic boron nitride composite polycrystalline material containing wurtzite-type boron nitride and possessing an X-ray diffraction intensity I of the (220) plane of cubic boron nitride. (220) X-ray diffraction intensity I relative to the (111) plane of cubic boron nitride (111) The ratio of I (220) / I (111) Orientation planes with a polarity below 0.1. In other words, in the orientation planes of this cubic boron nitride composite polycrystalline material, I... (111) For I (220) More than 10 times. That is, it can be said that the (111) plane is strongly oriented in the orientation plane. This cubic boron nitride composite polycrystalline material can be obtained by using pBN oriented as a raw material. It is also stated that, as a comparative example containing hexagonal boron nitride, even though the (111) plane is strongly oriented in the cubic boron nitride orientation plane, the wear is large and the performance as a cutting tool is poor.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 5929655 Summary of the Invention

[0007] One aspect of the present invention provides a cutting blade comprising a boron nitride sintered body having a first face, a second face, and a cutting edge located on at least a portion of the edges of the first and second faces. The boron nitride sintered body contains cubic boron nitride and compressed boron nitride. In transmission-type X-ray diffraction relative to a cross section of the boron nitride sintered body perpendicular to the first face, the X-ray intensity at the peak of the 111 diffraction of cubic boron nitride in a direction perpendicular to the first face is IcBN(111)v, and the X-ray intensity at the peak of the 002 diffraction of compressed boron nitride is IhBN(002)v; the X-ray intensity at the peak of the 111 diffraction of cubic boron nitride in a direction parallel to the first face is IcBN(111)h, and the X-ray intensity at the peak of the 002 diffraction of compressed boron nitride is IhBN(002)h. The compressible boron nitride content value, expressed as (IhBN(002)v+IhBN(002)h) / (IcBN(111)v+IcBN(111)h), is greater than 0.002 and less than 0.01. The cubic orientation value, expressed as IcBN(111)v / (IcBN(111)v+IcBN(111)h), is greater than 0.5. The compressible boron nitride orientation value, expressed as IhBN(002)v / (IhBNv(002)+IhBN(002)h), is greater than the cubic orientation value. Furthermore, in one embodiment of the present invention, the blade has a coating on at least a portion of the surface of the boron nitride sintered body.

[0008] One aspect of the present invention provides a cutting tool comprising: a tool holder having a length extending from a first end to a second end and having a groove on the first end side; and the aforementioned cutting insert located in the groove. Attached Figure Description

[0009] Figure 1 This is a perspective view showing an example of the blade of the present invention.

[0010] Figure 2 This is a perspective view showing another example of the blade of the present invention.

[0011] Figure 3 This is a cross-sectional view illustrating an example of the structure of the coating of the present invention.

[0012] Figure 4 yes Figure 3 An enlarged schematic diagram of section H is shown.

[0013] Figure 5 This is a diagram illustrating an example of the cutting tool of the present invention. Detailed Implementation

[0014] Hereinafter, embodiments (hereinafter referred to as "embodiments") of the blades and cutting tools used to implement the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments. Furthermore, the embodiments can be appropriately combined without contradicting the content of the process. In the following embodiments, the same reference numerals are used for the same parts, and repeated descriptions are omitted.

[0015] Furthermore, in the embodiments shown below, expressions such as "certain," "orthogonal," "perpendicular," or "parallel" are used, but these expressions do not need to be "certain," "orthogonal," "perpendicular," or "parallel" in a strict sense. That is, the above expressions allow for deviations in manufacturing precision, setting precision, etc.

[0016] In addition, for ease of explanation, the following figures only show the essential parts in a simplified manner.

[0017] Cutting tools formed from boron nitride sintered bodies are known. There is room for further improvement in the wear resistance of such cutting tools.

[0018] <Blade>

[0019] Figure 1 An example of the blade 1 of the present invention is shown in the figure. Figure 1 In the example shown, blade 1 is a polygonal boron nitride sintered body 3. Figure 2 Another example of the blade 1 of the present invention is shown in the figure. Figure 2 The image shows an example where a boron nitride sintered body 3 is bonded to a substrate 5, for example, formed of cemented carbide. The substrate 5 and the boron nitride sintered body 3 together form a polygonal cutting tool. With this structure, the proportion of the relatively expensive boron nitride sintered body 3 in the cutting tool 1 can be reduced. Figure 2 In the example, the boron nitride sintered body 3 is located at one of the multiple corners of the blade 1. However, it is not limited to this; the boron nitride sintered body 3 may also be located at two or more of the multiple corners of the blade 1.

[0020] Between the boron nitride sintered body 3 and the substrate 5, for example, a bonding material containing Ti and Ag (not shown) can be provided. The boron nitride sintered body 3 and the substrate 5 can be integrated via the bonding material using conventional bonding methods.

[0021] The boron nitride sintered body 3 has a first surface 7 and a second surface 9. Figure 1 and Figure 2 In the example shown, surface 7 (first surface) is the upper surface of blade 1, and surface 2 (second surface) is the side surface of blade 1. Additionally, in Figure 1 and Figure 2In the example shown, face 7 corresponds to the rake face, and face 9 corresponds to the flank face. Hereafter, face 7 is sometimes referred to as the rake face 7. In addition, face 9 is sometimes referred to as the flank face 9. The insert 1 has a cutting edge 13 on at least a portion of the edges of face 7 and face 9.

[0022] The boron nitride sintered body 3 of the blade 1 of the present invention contains cubic boron nitride and compressed boron nitride.

[0023] In the transmission-type X-ray diffraction data obtained relative to the cross section perpendicular to the first surface 7 of the boron nitride sintered body 3, the X-ray intensity of the 111 diffraction of cubic boron nitride perpendicular to the first surface 7 is set as IcBN(111)v. Additionally, the X-ray intensity of the 002 diffraction of compressed boron nitride perpendicular to the first surface 7 is set as IhBN(002)v. Furthermore, in the transmission-type X-ray diffraction data obtained relative to the cross section perpendicular to the first surface 7 of the boron nitride sintered body 3, the X-ray intensity of the 111 diffraction of cubic boron nitride parallel to the first surface 7 is set as IcBN(111)h. Additionally, the X-ray intensity of the 002 diffraction of compressed boron nitride parallel to the first surface 7 is set as IhBN(002)h.

[0024] Furthermore, the specific designations for each of the above aspects, regarding cubic boron nitride, are based on JCPDS card No. 01-075-6381. Additionally, regarding compressed boron nitride, they are based on JCPDS card No. 18-251. Regarding hexagonal boron nitride, they are based on JCPDS card No. 00-045-0893. Furthermore, regarding the fibrous wurtzite type boron nitride described later, they are based on JCPDS card No. 00-049-1327.

[0025] Transmission-type X-ray diffraction, for example, can be performed using the RINTRAPID2 curved IP X-ray diffraction apparatus manufactured by Rigaku Corporation.

[0026] The value of (IhBN(002)v+IhBN(002)h) / (I(111)v+IcBN(111)h), obtained based on the above X-ray intensities, is called the compressible boron nitride content value. The compressible boron nitride content value is an indicator related to the amount of compressible boron nitride contained in the boron nitride sintered body 3. The larger this value, the more compressible boron nitride is contained in the boron nitride sintered body 3. The compressible boron nitride content value is not the content itself.

[0027] In the boron nitride sintered body 3 of the blade 1 of the present invention, the content of compressible boron nitride is greater than 0.002 and less than 0.01. That is, the boron nitride sintered body 3 of the blade 1 of the present invention contains compressible boron nitride to a degree that satisfies this condition.

[0028] Furthermore, the IcBN(111)v / (IcBN(111)v+IcBN(111)h) obtained based on the aforementioned X-ray intensities is called the cubic crystal orientation value. If the cubic crystal orientation value is 0.5, the 111 facet of the cubic boron nitride is oriented in a random direction, which is a state of no orientation. The larger the cubic crystal orientation value, the greater the degree to which the 111 facet of the cubic boron nitride contained in the boron nitride sintered body 3 is parallel to the first facet 7.

[0029] In the boron nitride sintered body 3 of the blade 1 of the present invention, the cubic crystal orientation value is greater than 0.5. In other words, the X-ray intensity at the peak of the 111 diffraction of cubic boron nitride perpendicular to the direction is greater than the X-ray intensity at the peak of the 111 diffraction of cubic boron nitride parallel to the direction. That is, it can also be said that the 111 plane of cubic boron nitride is oriented along the normal direction of the first plane 7.

[0030] The value of IhBN(002)v / (IhBN(002)v+IhBN(002)h), obtained based on the aforementioned X-ray intensities, is called the compressible boron nitride orientation value. If the compressible boron nitride orientation value is 0.5, the 002 facet of the compressible boron nitride faces a random direction, indicating a non-oriented state. The larger the compressible boron nitride orientation value, the greater the degree to which the 002 facet of the compressible boron nitride contained in the boron nitride sintered body 3 is oriented parallel to the first facet 7.

[0031] In the boron nitride sintered body 3 of the blade 1 of the present invention, the compressible boron nitride orientation value is greater than the cubic orientation value. That is, the 002 facet of the compressible boron nitride is more parallel to the first facet 7 than the 111 facet of the cubic boron nitride.

[0032] The cutting blade 1 of the present invention, by having the above-described structure, exhibits excellent wear resistance. This effect is presumably due to the fact that the cutting blade 1 of the present invention contains a small amount of compressible boron nitride, and furthermore, the 002 facets of the compressible boron nitride are largely oriented in the first facet, thus the workpiece bonded to the first facet is peeled off along with the compressible boron nitride.

[0033] In the boron nitride sintered body 3 of the blade 1 of the present invention, the content of compressed boron nitride can be 0.004 or more and 0.008 or less. If such a structure is present, the blade 1 has high hardness.

[0034] Furthermore, in the boron nitride sintered body 3 of the blade 1 of the present invention, the cubic crystal orientation value can be 0.55 or higher. With such a structure, the hardness of the rake face 7 is high.

[0035] Furthermore, in the boron nitride sintered body 3 of the blade 1 of the present invention, the compressible boron nitride orientation value can be 0.8 or higher. With such a structure, the blade 1 has a long service life.

[0036] Furthermore, in the blade 1 of the present invention, the boron nitride sintered body 3 may contain fibrous wurtzite-type boron nitride. The boron nitride sintered body 3 with this structure has high hardness.

[0037] Furthermore, in the blade 1 of the present invention, the average particle size of cubic boron nitride can be 200 nm or less. With such a structure, the blade 1 has high strength. Also, the average particle size of cubic boron nitride can be 100 nm or less.

[0038] In addition, the blade 1 of the present invention may have a hard coating (not shown) on the surface of the boron nitride sintered body 3.

[0039] <Coating>

[0040] The blade 1 of the present invention may have a coating. The coating may be applied to the boron nitride sintered body 3 for, for example, purposes of improving the wear resistance, heat resistance, etc., of the boron nitride sintered body 3. Furthermore, in... Figure 2 In the blade 1 shown, the coating can also be applied to the boron nitride sintered body 3 and the substrate 5.

[0041] Here, refer to Figure 3 An example of the coating structure of blade 1 will be described. Figure 3 This is a cross-sectional view showing an example of the coating structure of the present invention.

[0042] like Figure 3 As shown, the blade 1 has a coating 20. The thickness of the coating 20 can be, for example, greater than 0.1 μm and less than 5.0 μm.

[0043] The coating 20 has a hard layer 21. Compared to the metal layer 22 described later, the hard layer 21 exhibits superior wear resistance. The hard layer 21 has one or more metal nitride layers. The hard layer 21 can be a single layer. Alternatively, it can be as follows... Figure 3 Multiple metal nitride layers are shown overlapping. Additionally, the hard layer 21 may have a stacked portion 23 of multiple metal nitride layers and a third metal nitride layer 24 located on top of the stacked portion 23. The structure of the hard layer 21 will be described later.

[0044] In addition, coating 20 has a metal layer 22. The metal layer 22 is located between the boron nitride sintered body 3 and the hard layer 21. Specifically, the metal layer 22 is in contact with the upper surface of the boron nitride sintered body 3 on a first surface (here, the lower surface) and with the lower surface of the hard layer 21 on a second surface (here, the upper surface) located on the opposite side of the first surface.

[0045] The bonding strength between the metal layer 22 and the boron nitride sintered body 3 is higher than that between the metal layer 21 and the hard layer 21. Examples of metal elements possessing this property include Zr, V, Cr, W, Al, Si, and Y. The metal layer 22 contains at least one of the aforementioned metal elements.

[0046] Furthermore, elemental Ti, Zr, V, Cr, and Al cannot be used as metal layer 22. This is because they all have low melting points and low oxidation resistance, making them unsuitable for use with cutting tools. Additionally, elemental Hf, Nb, Ta, and Mo exhibit poor adhesion to the boron nitride sintered body 3. However, this limitation does not apply to alloys containing Ti, Zr, V, Cr, Ta, Nb, Hf, and Al.

[0047] The metal layer 22 can be an Al-Cr alloy layer containing an Al-Cr alloy. Such a metal layer 22 has a particularly high bonding strength with the boron nitride sintered body 3, thus greatly improving the bonding strength between the boron nitride sintered body 3 and the coating 20.

[0048] When metal layer 22 is an Al-Cr alloy layer, the Al content in metal layer 22 can be greater than the Cr content in metal layer 22. For example, the composition ratio (atomic %) of Al to Cr in metal layer 22 can be 70:30. By achieving such a composition ratio, the bonding strength between boron nitride sintered body 3 and metal layer 22 is higher.

[0049] Metal layer 22 may also contain components other than the aforementioned metallic elements (Zr, V, Cr, W, Al, Si, Y). However, from the viewpoint of bonding with the boron nitride sintered body 3, metal layer 22 may contain at least 95 atomic% of the aforementioned metallic elements in total. More preferably, metal layer 22 contains at least 98 atomic% of the aforementioned metallic elements in total. For example, when metal layer 22 is an Al-Cr alloy layer, metal layer 22 may contain at least 95 atomic% of Al and Cr in total. Furthermore, metal layer 22 may contain at least 98 atomic% of Al and Cr in total. Also, the proportion of metallic components in metal layer 22 can be determined, for example, by analysis using an EDS (energy-dispersive X-ray spectrometer).

[0050] Furthermore, since Ti has poor wettability with the boron nitride sintered body 3, from the viewpoint of improving the bonding with the boron nitride sintered body 3, it is preferable that the metal layer 22 contains as little Ti as possible. Specifically, the Ti content in the metal layer 22 can be 15 atomic% or less.

[0051] Thus, in the blade 1 of the present invention, by providing a metal layer 22 with a higher wettability to the boron nitride sintered body 3 than to the hard layer 21 between the boron nitride sintered body 3 and the hard layer 21, the adhesion between the boron nitride sintered body 3 and the coating 20 can be improved. Furthermore, because the adhesion between the metal layer 22 and the hard layer 21 is also high, it is less likely that the hard layer 21 will peel off from the metal layer 22.

[0052] Furthermore, the boron nitride sintered body 3 is an insulator. As an insulator, the boron nitride sintered body 3 has room for improvement in its adhesion to the film formed by PVD (physical vapor deposition). In contrast, the blade 1 of the present invention has a high degree of adhesion between the hard layer 21 formed by PVD and the metal layer 22 because the conductive metal layer 22 is located on the surface of the boron nitride sintered body 3.

[0053] Next, refer to Figure 4 The structure of the hard layer 21 will be described. Figure 4 yes Figure 3 An enlarged schematic diagram of section H is shown.

[0054] like Figure 4 As shown, the hard layer 21 has a stacked portion 23 located above the metal layer 22 and a third metal nitride layer 24 located above the stacked portion 23.

[0055] The laminated portion 23 has a plurality of first metal nitride layers 23a and a plurality of second metal nitride layers 23b. The laminated portion 23 has a structure in which the first metal nitride layers 23a and the second metal nitride layers 23b are alternately laminated.

[0056] The thicknesses of the first metal nitride layer 23a and the second metal nitride layer 23b can be 10 nm or more and 50 nm or less, respectively. By forming the first metal nitride layer 23a and the second metal nitride layer 23b very thinly, the residual stress in the first metal nitride layer 23a and the second metal nitride layer 23b is low. Therefore, for example, peeling and cracking of the first metal nitride layer 23a and the second metal nitride layer 23b are less likely to occur, resulting in high durability of the coating 20.

[0057] The first metal nitride layer 23a is in contact with the metal layer 22, and the second metal nitride layer 23b is formed on the first metal nitride layer 23a.

[0058] The first metal nitride layer 23a and the second metal nitride layer 23b may also contain the metal contained in the metal layer 22.

[0059] For example, metal layer 22 contains two metals (here, "first metal" and "second metal"). In this case, first metal nitride layer 23a contains nitrides of the first metal and the third metal. The third metal is a metal not contained in metal layer 22. Additionally, second metal nitride layer 23b contains nitrides of the first metal and the second metal.

[0060] For example, in one embodiment, metal layer 22 may also contain Al and Cr. In this case, the first metal nitride layer 23a may contain Al. Specifically, the first metal nitride layer 23a may be an AlTiN layer containing AlTiN as a nitride of Al and Ti. Furthermore, the second metal nitride layer 23b may be an AlCrN layer containing AlCrN as a nitride of Al and Cr.

[0061] In this way, the first metal nitride layer 23a containing the metal contained in the metal layer 22 is located on top of the metal layer 22, and the adhesion between the metal layer 22 and the hard layer 21 is high. As a result, the hard layer 21 is difficult to peel off from the metal layer 22, and therefore the coating 20 has high durability.

[0062] The first metal nitride layer 23a, namely the AlTiN layer, exhibits excellent adhesion to the metal layer 22, and also possesses superior wear resistance. Furthermore, the second metal nitride layer 23b, namely the AlCrN layer, exhibits excellent heat resistance and oxidation resistance. Thus, by including the first metal nitride layer 23a and the second metal nitride layer 23b with different compositions, the coating 20 can control the wear resistance and heat resistance, among other properties, of the hard layer 21. This extends the tool life of the cutting tool 1. For example, in the hard layer 21 of this embodiment, the excellent heat resistance of AlCrN can be maintained, and mechanical properties such as adhesion to the metal layer 22 and wear resistance can be improved.

[0063] In this way, at least a portion of the coating 20 can be stacked with multiple layers (first metal nitride layer 23a and second metal nitride layer 23b) each having a thickness of more than 10 nm and less than 50 nm.

[0064] Furthermore, the laminate 23 can be formed, for example, by arc ion plating (AIP). AIP is a method that uses an electric arc discharge in a vacuum atmosphere to evaporate the target metal (in this case, AlTi and AlCr targets), which then combines with N2 gas to form a metal nitride film (in this case, AlTiN and AlCrN). Additionally, the metal layer 22 can also be formed by AIP.

[0065] The third metal nitride layer 24 may also be located on the stack 23. Specifically, the third metal nitride layer 24 is in contact with the second metal nitride layer 23b in the stack 23. The third metal nitride layer 24, for example, like the first metal nitride layer 23a, is a metal nitride layer containing Ti and Al (AlTiN layer).

[0066] The thickness of the third metal nitride layer 24 can be greater than the thicknesses of the first metal nitride layer 23a and the second metal nitride layer 23b. Specifically, if the thicknesses of the first metal nitride layer 23a and the second metal nitride layer 23b are 50 nm or less, the thickness of the third metal nitride layer 24 can be 1 μm or more. For example, the thickness of the third metal nitride layer 24 can be 1.2 μm.

[0067] Therefore, for example, when the coefficient of friction of the third metal nitride layer 24 is low, the anti-adhesion property of the cutting tool 1 can be improved. Furthermore, for example, when the hardness of the third metal nitride layer 24 is high, the wear resistance of the cutting tool 1 can be improved. Additionally, for example, when the oxidation initiation temperature of the third metal nitride layer 24 is high, the oxidation resistance of the cutting tool 1 can be improved.

[0068] Furthermore, the thickness of the third metal nitride layer 24 can be greater than the thickness of the laminate 23. Specifically, in this embodiment, when the thickness of the laminate 23 is 0.5 μm or less, the thickness of the third metal nitride layer 24 can be 1 μm or more. For example, when the thickness of the laminate 23 is 0.3 μm, the thickness of the third metal nitride layer 24 can be 1.2 μm. Thus, by making the third metal nitride layer 24 thicker than the laminate 23, the aforementioned improvements in anti-adhesion, wear resistance, etc., are even greater.

[0069] Furthermore, the thickness of the metal layer 22 can be, for example, 0.1 μm or more and less than 0.6 μm. That is, the metal layer 22 can be thicker than the first metal nitride layer 23a and the second metal nitride layer 23b respectively, and can be thinner than the laminate 23.

[0070] <Cutting Tools>

[0071] Next, refer to Figure 5 The cutting tool of the present invention will be described. Figure 5 This is a diagram illustrating an example of the cutting tool of the present invention.

[0072] The cutting tool 101 of the present invention, such as Figure 5 As shown, for example, it is from the first end ( Figure 5 The upper end of the middle) faces the second end ( Figure 5 A rod-shaped body extending from the lower end of the middle.

[0073] Cutting tool 101, such as Figure 5As shown, the tool includes: a tool holder 105 having a length extending from a first end (front end) to a second end, and a slot 103 located on the first end side; and the aforementioned cutting insert 1 located in the slot 103. Because the cutting tool 101 includes the cutting insert 1, it can perform stable cutting operations over a long period of time.

[0074] The slot 103 is the part for mounting the blade 1, and has a support surface parallel to the lower surface of the tool holder 105, and a limiting side that is perpendicular or inclined to the support surface. In addition, the slot 103 has an opening at the first end side of the tool holder 105.

[0075] The blade 1 is located in the slot 103. At this time, the lower surface of the blade 1 can be directly in contact with the slot 103. In addition, a spacer (not shown) can also be clamped between the blade 1 and the slot 103.

[0076] The blade 1 is mounted on the shank 105 in such a way that at least a portion of the edge where the rake face 7 and the flank face 9 intersect protrudes outward from the shank 105 as the cutting edge 13. In this embodiment, the blade 1 is mounted on the shank 105 by a fixing bolt 107. That is, the fixing bolt 107 is inserted into the through hole 55 of the blade 1, and the front end of the fixing bolt 107 is inserted into the screw hole (not shown) formed in the slot 103, and the threads are tightened, thereby mounting the blade 1 on the shank 105.

[0077] For the handle 105, materials such as steel and cast iron can be used. Among these components, high-toughness steel can be used.

[0078] In this embodiment, a cutting tool for so-called turning is exemplified. Examples of turning include, for instance, internal diameter machining, external diameter machining, and grooving. However, the cutting tool is not limited to turning. For example, the insert 1 described above can also be used as a cutting tool for milling.

[0079] <Manufacturing Method>

[0080] The following describes the method for manufacturing the boron nitride sintered body of the blade of the present invention. First, flat hexagonal boron nitride powder is prepared as the raw material powder. Commercially available raw materials with an average particle size of 0.7 μm or more and an oxygen impurity content of less than 0.5% by mass are used. The average particle size of the hexagonal boron nitride powder refers to the average length of the boron nitride powder along its long axis as measured by an electron microscope. The average particle size of the hexagonal boron nitride powder can be 0.2 μm or more and 30 μm or less. The hexagonal boron nitride powder can also be of high purity, with a purity of 99% or more. Additionally, it may contain catalyst components used in manufacturing cubic boron nitride powder. Alternatively, raw material powder with a purity of less than 99% may also be used.

[0081] The raw material powder is formed by uniaxial pressing. By controlling the pressure during forming, the cubic crystal orientation value and the compressed boron nitride orientation value after firing can be controlled. During uniaxial pressing, the flat hexagonal boron nitride powder is oriented, with the 002 facet of the hexagonal boron nitride powder oriented perpendicular to the pressing axis. If the same formed body is repeatedly pressed under pressure, the orientation of the hexagonal boron nitride powder in the formed body will be high.

[0082] Next, the molded body prepared by the above method is fired at a temperature of 1800–2200 degrees Celsius and a pressure of 8–10 GPa, thereby obtaining the boron nitride sintered body of the present invention. The proportion of compressible boron nitride contained in the boron nitride sintered body can be controlled by the temperature and pressure during firing. Furthermore, according to the above manufacturing method, a coating can be formed on the boron nitride sintered body.

[0083] The boron nitride sintered body, blade, and cutting tool of the present invention have been described above, but are not limited to the embodiments described above. Various modifications and alterations can be made without departing from the spirit of the present invention.

[0084] Example

[0085] Flat hexagonal boron nitride powders with average particle sizes of 0.3 μm, 6 μm, and 16 μm and an oxygen impurity content of 0.3% by mass were shaped by uniaxial pressing to obtain molded bodies. Alternatively, molded bodies were prepared by isobaric pressing of the same hexagonal boron nitride powder. These molded bodies were sintered under the conditions shown in Table 1.

[0086] Next, the sintered body was cut along a direction perpendicular to the first surface of the sintered body to prepare a test piece with a thickness of approximately 0.5 mm and a surface intersecting the first surface at a right angle. Using the cross-section perpendicular to the first surface of this test piece as a reference, the compressible boron nitride content, cubic orientation value, and compressible boron nitride orientation value were determined using a bent IP X-ray diffractometer RINT RAPID2 manufactured by Rigaku Corporation. The obtained values ​​are shown in Table 1. Furthermore, a portion of the obtained sintered body was cut to prepare a cutting tool. Additionally, a sample with a coating on the surface of the cutting tool was also prepared. The composition of this coating is shown in Table 2. Furthermore, in the following tests, cutting tools without coating and cutting tools with two types of coatings were evaluated.

[0087] Table 1

[0088] (Table 1)

[0089]

[0090] Table 2

[0091]

[0092] Cutting tests were conducted using the first face of these inserts as the rake face. The conditions for the cutting tests are shown below.

[0093] <Conditions for cutting test>

[0094] Workpiece material: Ti alloy (Ti-6Al-4V)

[0095] Cutting conditions: Vc = 100 m / min, f = 0.1 mm / rev, ap = 0.4 mm, Wet

[0096] Tool used: CNGA120408

[0097] The samples obtained from the isobaric molded bodies, namely samples No. 1 to 3, 7, 11, and 15, do not possess the boron nitride sintered body structure of the blade of the present invention. Furthermore, even when using uniaxially pressurized molded bodies, samples No. 8 to 10, with a firing temperature of 2100°C and a firing pressure of 11 GPa, do not contain compressible boron nitride. While sample No. 16, with a firing temperature of 2300°C and a firing pressure of 7.7 GPa, contains compressible boron nitride, its orientation value is smaller than that of cubic crystals.

[0098] On the other hand, among the samples formed by uniaxial pressing, samples No. 4–6 and 12–14 have a compressible boron nitride content of less than 0.005 and a cubic orientation value greater than 0.5, indicating a long lifespan. Furthermore, the average particle size of the cubic boron nitride in samples No. 4–6 and 12–14 is all below 200 nm. In particular, samples No. 4 and No. 12, which used raw material powder with a small average particle size, have an average particle size of less than 100 nm.

[0099] Samples No. 5, 6, 12, 13, and 14, with a cubic orientation value of 0.55 or higher, have a longer lifetime than sample No. 4, which has a cubic orientation value below 0.55. Samples No. 13 and 14, with a compressed boron nitride orientation value of 0.8 or higher, have a longer lifetime than sample No. 12, which has a compressed boron nitride orientation value below 0.8.

[0100] Samples that do not meet the constituent requirements of the boron nitride sintered body for the blades of the present invention have shorter lifespans than samples No. 4-6 and 12-14, which are blades of the present invention. Regardless of the sample, the blades with coatings have longer lifespans than those without coatings. In particular, blades with metal layers have very long lifespans.

[0101] The embodiments disclosed herein should be considered illustrative rather than restrictive. In fact, the above embodiments can be implemented in various ways. Furthermore, the above embodiments can be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0102] Symbol Explanation

[0103] 1…blade

[0104] 3…boron nitride sintered body

[0105] 5…Matrix

[0106] 7…Front face

[0107] 9…back face

[0108] 13…blade edge

[0109] 20…coating

[0110] 21…hard layer

[0111] 22…metal layer

[0112] 23…Layered section

[0113] 23a…First metal nitride layer

[0114] 23b…Second metal nitride layer

[0115] 24…Third metal nitride layer

[0116] 101…Cutting tools

[0117] 103…card slot

[0118] 105…handle.

Claims

1. A cutting blade comprising a boron nitride sintered body having a first face, a second face, and a cutting edge located on at least a portion of the edges of the first face and the second face, wherein, The boron nitride sintered body contains cubic boron nitride and compressed boron nitride. In transmission X-ray diffraction relative to a cross section of the boron nitride sintered body perpendicular to the first plane, Let the X-ray intensity at the apex of the 111 diffraction peak of the cubic boron nitride in the direction perpendicular to the first plane be IcBN(111)v, and the X-ray intensity at the apex of the 002 diffraction peak of the compressed boron nitride be IhBN(002)v. Let the X-ray intensity at the apex of the 111 diffraction peak of the cubic boron nitride in the direction parallel to the first plane be IcBN(111)h, and the X-ray intensity at the apex of the 002 diffraction peak of the compressed boron nitride be IhBN(002)h. The compressed boron nitride content, represented by (IhBN(002)v + IhBN(002)h) / (IcBN(111)v + IcBN(111)h), is greater than 0.002 and less than 0.

01. The cubic orientation value represented by IcBN(111)v / (IcBN(111)v+IcBN(111)h) is greater than 0.

5. The compressed boron nitride orientation value, represented by IhBN(002)v / (IhBN(002)v+IhBN(002)h), is greater than the cubic crystal orientation value. At least a portion of the surface of the boron nitride sintered body has a coating. Furthermore, the thickness of the coating is 0.1 μm or more and 5.0 μm or less.

2. The blade according to claim 1, wherein, The cubic crystal orientation value is 0.55 or higher.

3. The blade according to claim 1 or 2, wherein, The compressed boron nitride orientation value is 0.8 or higher.

4. The blade according to claim 1 or 2, wherein, The boron nitride sintered body contains fibrous wurtzite-type boron nitride.

5. The blade according to claim 1 or 2, wherein, The average particle size of the cubic boron nitride in the cross section is less than 200 nm.

6. The blade according to claim 1 or 2, wherein, The coating has multiple layers stacked together, and the coating in contact with the boron nitride sintered body is formed of metal.

7. The blade according to claim 6, wherein, The metal is composed of metals other than elemental Ti, Zr, V, Cr, Ta, Nb, Hf, and Al.

8. The blade according to claim 7, wherein, The metal contains at least one element selected from Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y.

9. The blade according to claim 1 or 2, wherein, At least a portion of the coating is stacked with multiple layers, each with a thickness of more than 10 nm and less than 50 nm.

10. A cutting tool comprising: a tool holder having a length extending from a first end to a second end and having a groove on the side of the first end; The blade of any one of claims 1 to 9 is located in the slot.

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