JP2013216517A - Ceramic sintered compact and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic sintered compact having high hardness and toughness, and a method for manufacturing the same.SOLUTION: A ceramic sintered compact includes cubic aluminum nitride, and at least one kind of metal compound selected from a group comprising nitrides, carbides and borides of groups 4A, 5A and 6A metals in the periodic table. A method for manufacturing the ceramic sintered compact includes a step for mixing cubic aluminum nitride powder with at least one kind of metal compound powder selected from the group comprising nitrides, carbides and borides of the groups 4A, 5A and 6A metals in the periodic table, and a step for sintering a mixture obtained by mixing at a temperature of ≥700°C and ≤1,500°C and at a pressure of ≥2 GPa and ≤20 GPa.

Description

  The present invention relates to a ceramic sintered body and a manufacturing method thereof, and more particularly to a ceramic sintered body containing aluminum nitride and a manufacturing method thereof.

As a material for a cutting tool used for cutting or the like, an aluminum oxide (Al ₂ O ₃ ) sintered body is known. Aluminum oxide sintered bodies are excellent in that they have low reactivity with iron-based work materials and can be manufactured at low cost, but their toughness tends to be low. For this reason, the aluminum oxide sintered body tends to be easily damaged when used as a cutting tool. Furthermore, since the reactivity between aluminum oxide and the metal compound as the binder is low, the nitrides, carbonitrides, etc. of the metals in groups 4A, 5A and 6A of the periodic table are used as the binder. It is difficult to do.

  On the other hand, Japanese Patent Application Laid-Open No. 2001-089242 (Patent Document 1) and Japanese Patent Application Laid-Open No. 04-300288 (Patent Document 2) have high hardness, strength and toughness from a low temperature region to a high temperature region, and have a thermal shock resistance. Disclosed is a ceramic sintered member containing aluminum nitride and a titanium compound as a ceramic sintered material having high heat resistance and thermal crack resistance.

  Japanese Patent Application Laid-Open No. 2004-284851 (Patent Document 3) reduces the pressure of the carrier gas and the hexagonal aluminum nitride powder that is stable under normal pressure (referred to below as atmospheric pressure) as an aerosol state. A method is disclosed in which the crystal structure is changed to powder of tetragonal aluminum nitride by spraying onto the substrate in the film forming chamber by impact when the substrate collides with the substrate.

JP 2001-089242 A Japanese Patent Laid-Open No. 04-3000248 JP 2004-284851 A

  The aluminum nitride described in Japanese Patent Application Laid-Open No. 2001-089242 (Patent Document 1) and Japanese Patent Application Laid-Open No. 04-300288 (Patent Document 2) does not clearly specify the crystal structure of hexagonal crystal or cubic crystal. When a sample is actually produced by a sintering method such as the HIP (hot isostatic pressing) method described, even if cubic aluminum nitride is used as a raw material, the crystal structure has a hexagonal crystal that is stable at normal pressure. There was a problem that the hardness was insufficient although the thermal conductivity was high. For this reason, cubic aluminum nitride is considered desirable as the aluminum nitride forming the ceramic sintered body.

  According to the method described in Japanese Patent Application Laid-Open No. 2004-284851 (Patent Document 3), only powdered or thin film cubic aluminum nitride can be obtained, and a sintered body mainly composed of cubic aluminum nitride cannot be obtained. There was a problem.

  An object of the present invention is to solve the above problems and provide a ceramic sintered body having high hardness and toughness and a method for producing the same.

  According to one aspect, the present invention includes cubic aluminum nitride and nitrides, carbides, oxides, borides, and solid solutions of metals of Groups 4A, 5A, and 6A of the periodic table. A ceramic sintered body containing at least one metal compound selected from the group.

  In the ceramic sintered body according to the present invention, the content of cubic aluminum nitride can be 20% by volume or more and 80% by volume or less. Further, cubic aluminum nitride can contain oxygen in an amount of 0.1 atomic% to 5 atomic%. Moreover, the ceramic sintered body according to the present invention can further include at least one selected from the group consisting of hexagonal aluminum nitride, aluminum oxynitride, and aluminum oxide. Here, the content rate of hexagonal aluminum nitride can be 0.1 volume% or more and 50 volume% or less. Moreover, the content rate of aluminum oxynitride can be 0.1 volume% or more and 20% volume% or less. Moreover, the content rate of aluminum oxide can be 0.1 volume% or more and 10 volume% or less.

  According to another aspect of the present invention, cubic aluminum nitride powder, nitrides, carbides, oxides, borides and metals of Group 4A, Group 5A and Group 6A of the periodic table And a step of mixing at least one metal compound powder selected from the group consisting of solid solutions of the above, and sintering the mixture obtained by the mixing at a temperature of 700 ° C. to 1500 ° C. at a pressure of 2 GPa to 20 GPa And a process for producing a ceramic sintered body.

  In the method for producing a ceramic sintered body according to the present invention, aluminum oxynitride powder can be further mixed in the mixing step. Here, the cubic aluminum nitride powder can be one in which the crystal structure of the hexagonal aluminum powder is changed by applying a pressure of 10 GPa or more to the hexagonal aluminum nitride powder. In addition, the cubic aluminum nitride powder is obtained by changing the crystal structure of the hexagonal aluminum nitride powder by a method of shock compressing the hexagonal aluminum nitride powder with a shock wave having a pressure of 10 GPa or more and a pressing time of 5 microseconds or less. be able to. Further, the cubic aluminum nitride powder is formed by spraying hexagonal aluminum nitride powder onto a substrate in a processing chamber at atmospheric pressure with a carrier gas having a pressure of 1 MPa or more, and the crystal structure of the hexagonal aluminum nitride powder by impact when colliding with the substrate. May have changed. In addition, cubic aluminum nitride powder sprays hexagonal aluminum nitride and carrier gas into an aerosol state and blows it to the substrate in the decompressed process chamber, and the crystal structure of the hexagonal aluminum nitride powder changes due to impact when it collides with the substrate. Can be.

  ADVANTAGE OF THE INVENTION According to this invention, the ceramic sintered compact which has high hardness and toughness, and its manufacturing method can be provided.

[Embodiment 1]
A ceramic sintered body according to an embodiment of the present invention includes cubic aluminum nitride (hereinafter also referred to as c-AlN), and nitrides of metals of Groups 4A, 5A, and 6A of the periodic table, And at least one metal compound selected from the group consisting of carbides, oxides, borides, and solid solutions thereof. The ceramic sintered body of the present embodiment is composed of c-AlN (cubic aluminum nitride) and nitrides, carbides, oxides, borides, and solid solutions of Group 4A, Group 5A and Group 6A metals. Since it contains at least one metal compound selected from the group, it has high hardness and toughness. In particular, since the ceramic sintered body of the present embodiment contains c-AlN, which is not highly stable compared to hexagonal aluminum nitride (hereinafter also referred to as h-AlN) at normal pressure, And high toughness. Such a ceramic sintered body containing c-AlN in a stable state can be obtained by the manufacturing method of Embodiment 2 described later.

(Cubic aluminum)
C-AlN contained in the ceramic sintered body of the present embodiment has a cubic crystal structure. Such c-AlN has higher hardness and toughness than h-AlN having a hexagonal crystal structure. At normal pressure, h-AlN is more stable than c-AlN. When a pressure of 10 GPa or more is applied to h-AlN, the crystal structure changes from hexagonal to tetragonal to obtain c-AlN. It is done.

  Further, such c-AlN contains oxygen (O) in an amount of 0.1 atomic% to 5 atomic%, more specifically, oxygen (O) is 0.1 atomic% to 5 atomic%. In this case, the crystal structure of c-AlN is stabilized, and it is possible to prevent c-AlN from being reversely converted to h-AlN during decompression after sintering. Here, the oxygen content (atomic%) in c-AlN is measured by SEM-EDX (scanning electron microscope-energy dispersive X-ray spectroscopy) or AES (Auger electron spectroscopy) method.

  Although there is no restriction | limiting in particular in the content rate of c-AlN in the ceramic sintered compact of this embodiment, From a viewpoint of making the hardness and toughness of a ceramic sintered compact high, 20 volume% or more and 80 volume% or less are preferable.

(Metal compound)
The metal compound contained in the ceramic sintered body of the present embodiment is a group consisting of nitrides, carbides, oxides, borides, and solid solutions of metals of Groups 4A, 5A, and 6A of the periodic table At least one metal compound selected from the group consisting of: These metal compounds have a function as a binder for bonding particles of the raw material powder, and increase the hardness and toughness of the ceramic sintered body.

Specifically, the metals of Group 4A, Group 5A and Group 6A in the periodic table are titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), Tantalum (Ta), chromium (Cr), molybdenum (Mo), and tungsten (W). These metal nitrides are titanium nitride (TiN), zirconium nitride (ZrN), hafnium nitride (HfN), vanadium nitride (VN), niobium nitride (NbN), tantalum nitride (TaN), chromium nitride (Cr ₂ ). N, CrN), molybdenum nitride (MoN), tungsten nitride (WN), and the like. These metal carbides include titanium carbide (TiC), zirconium carbide (ZrC), hafnium carbide (HfC), vanadium carbide (VC), niobium carbide (NbC), tantalum carbide (TaC), chromium carbide (Cr ₃ C). ₂ ), molybdenum carbide (Mo ₂ C), tungsten carbide (WC), and the like. These metal oxides include titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), hafnium oxide (HfO ₂ ), vanadium oxide (V ₂ O ₅ ), niobium oxide (Nb ₂ O ₅ ), and tantalum oxide. (Ta ₂ O ₅ ), chromium oxide (Cr ₂ O ₃ ), molybdenum oxide (MoO ₃ ), tungsten oxide (WO ₃ ), and the like. These metal borides include titanium boride (TiB ₂ ), zirconium boride (ZrB ₂ ), hafnium boride (HfB ₂ ), vanadium boride (VB ₂ ), niobium boride (NbB ₂ ), boron Tantalum boride (TaB ₂ ), chromium boride (CrB ₂ ), molybdenum boride (MoB), tungsten boride (WB), and the like.

  The solid solution means a solid solution containing a plurality of compounds of those metals, and includes a solid solution containing a plurality of elements selected from the group consisting of nitrogen, carbon, oxygen and boron, a solid solution containing a plurality of those metals, and the like. It is. In addition, the ratio of the metal and other elements contained in the solid solution is not particularly limited.

  The solid solution containing a plurality of elements selected from the group consisting of nitrogen, carbon, oxygen and boron includes, for example, carbonitrides of those metals, oxynitrides of those metals, and the like. These metal carbonitrides include titanium carbonitride, zirconium carbonitride, hafnium carbonitride, vanadium carbonitride, niobium carbonitride, tantalum carbonitride, chromium carbonitride, molybdenum carbonitride and tungsten carbonitride. These metal oxynitrides include titanium oxynitride, zirconium oxynitride, hafnium oxynitride, vanadium oxynitride, niobium oxynitride, tantalum oxynitride, chromium oxynitride, molybdenum oxynitride, tungsten oxynitride, and the like.

  The solid solution containing a plurality of these metals includes, for example, a nitride containing a plurality of these metals, a carbide containing a plurality of these metals, an oxide containing a plurality of these metals, and the like.

  The nitride containing a plurality of these metals is titanium zirconium nitride, titanium nitride hafnium, titanium nitride vanadium, titanium niobium nitride, titanium tantalum nitride, titanium nitride chromium, titanium molybdenum nitride, titanium tungsten nitride, zirconium nitride hafnium, zirconium vanadium nitride, Zirconium niobium nitride, zirconium tantalum nitride, zirconium chromium nitride, zirconium molybdenum nitride, zirconium tungsten nitride, hafnium vanadium nitride, hafnium niobium, hafnium tantalum nitride, hafnium chromium nitride, hafnium molybdenum nitride, hafnium tungsten nitride, vanadium niobium nitride, vanadium nitride Tantalum, vanadium nitride chromium, vanadium molybdenum nitride, vanadium tungsten nitride, nitriding Of tantalum, nitride Niobukuromu refers niobium molybdenum nitride, niobium, tungsten nitride, tantalum nitride chromium, tantalum nitride, molybdenum, tantalum nitride, tungsten, chromium, molybdenum nitride, chromium, tungsten nitride, a molybdenum nitride chromium.

  Carbides containing a plurality of these metals include titanium zirconium carbide, titanium hafnium carbide, titanium vanadium carbide, titanium niobium carbide, titanium tantalum carbide, titanium chromium carbide, titanium molybdenum carbide, titanium tungsten carbide, zirconium carbide hafnium, zirconium vanadium carbide, and carbonized. Zirconium niobium, zirconium tantalum carbide, zirconium chromium carbide, zirconium carbide, zirconium carbide tungsten, hafnium vanadium carbide, hafnium niobium, hafnium tantalum carbide, hafnium chromium carbide, hafnium molybdenum carbide, hafnium tungsten carbide, vanadium niobium carbide, vanadium tantalum carbide , Vanadium chromium carbide, vanadium molybdenum carbide, vanadium tungsten carbide, carbonized Of tantalum carbide Niobukuromu, niobium carbide, molybdenum, refers niobium carbide, tungsten, tantalum carbide chromium, tantalum carbide, molybdenum, tantalum, tungsten carbide, chromium carbide, molybdenum, chromium carbide, tungsten, etc. molybdenum carbide chromium.

  The oxide containing a plurality of these metals includes titanium zirconium oxide, titanium hafnium oxide, titanium vanadium oxide, titanium niobium oxide, titanium tantalum oxide, titanium chromium oxide, titanium molybdenum oxide, titanium tungsten oxide, zirconium hafnium oxide, zirconium vanadium oxide, Zirconium niobium oxide, zirconium tantalum oxide, zirconium chromium oxide, zirconium molybdenum oxide, tungsten zirconium oxide, hafnium vanadium oxide, hafnium niobium oxide, hafnium tantalum oxide, hafnium chromium oxide, hafnium molybdenum oxide, hafnium tungsten oxide, vanadium niobium oxide, vanadium oxide Tantalum, vanadium chrome oxide, vanadium molybdenum oxide, vanadium tungsten oxide, oxidation Of tantalum oxide Niobukuromu, niobium oxide, molybdenum oxide, niobium, tungsten, tantalum oxide, chromium oxide, tantalum, molybdenum, tantalum oxide, tungsten, say chromium oxide, molybdenum oxide, chromium, tungsten, and molybdenum oxide chromium.

  When two or more types of the metal compounds are included in the ceramic sintered body of the present embodiment, a mixture of two or more types of the metal compounds may be used, or a solid solution of two or more types of the metal compounds may be used. .

  Although the content rate of the said metal compound in the ceramic sintered compact of this embodiment does not have a restriction | limiting in particular, From a viewpoint of making the hardness and toughness of a ceramic sintered compact high, 20 volume% or more and 80 volume% or less are preferable.

  The ceramic sintered body of the present embodiment can further include at least one selected from the group consisting of hexagonal aluminum nitride, aluminum oxynitride, and aluminum oxide.

(Hexagonal aluminum nitride)
By including h-AlN (hexagonal aluminum), the ceramic sintered body of the present embodiment has higher toughness and excellent fracture resistance. The content of h-AlN in the ceramic sintered body is preferably 0.1% by volume or more and 50% by volume or less from the viewpoint of obtaining a ceramic sintered body having high toughness and excellent fracture resistance.

(Aluminum oxynitride)
By including AlON (aluminum oxynitride) in the ceramic sintered body of the present embodiment, the stability of c-AlN, which is less stable than h-AlN at normal pressure, is enhanced. The content of AlON in the ceramic sintered body is preferably 0.1% by volume or more and 20% by volume or less from the viewpoint of obtaining a ceramic sintered body in which c-AlN is more stable.

(Aluminum oxide)
By including Al ₂ O ₃ (aluminum oxide), the ceramic sintered body of the present embodiment has higher hardness and excellent oxidation resistance. The content of Al ₂ O ₃ in the ceramic sintered body is preferably 0.1% by volume or more and 10% or less from the viewpoint of obtaining a ceramic sintered body having high hardness and excellent oxidation resistance.

Here, the content (volume%) of the metal compound, AlN (the whole of c-AlN and h-AlN), AlON, and Al ₂ O ₃ in the ceramic sintered body of the present embodiment has a particle size of 2 μm. In the above case, it is measured by mapping by SEM-EDX (scanning electron microscope-energy dispersive X-ray spectroscopy), and when the particle size is less than 2 μm, by AES (Auger electron spectroscopy). The content (volume%) of each of c-AlN and h-AlN in AlN is the same as the content (volume%) of AlN measured by the above mapping, measured by the XRD (X-ray diffraction) method. It is calculated by multiplying the respective diffraction intensity ratios of AlN and h-AlN. The diffraction planes generally used in the XRD method are (200) planes of c-AlN and (100) planes of h-AlN, and the diffraction intensity at these diffraction planes is JCPDS (Joint Committee on Powder Diffraction Standards). As described on the card (specifically, the diffraction intensity of the c-AlN (200) plane is Ic / 0.75 and the diffraction intensity of the h-AlN (100) plane is Ih / 1.0). The Therefore, (Ic / 0.75) / (Ic / 0.75 + Ih / 1.0) is used as the diffraction intensity ratio of c-AlN, and (Ih / 1.0) / () as the diffraction intensity ratio of h-AlN. Ic / 0.75 + Ih / 1.0) is used.

  Since the ceramic sintered body of the present embodiment contains c-AlN having high hardness and high toughness, the ceramic sintered body is excellent in wear resistance and fracture resistance, and excellent in reactive wear resistance with a work material such as iron. . Moreover, the ceramic sintered compact of this embodiment contains h-AlN in addition to c-AlN, and it can aim at the balance of high hardness and high toughness by controlling these content rates. By using the ceramic sintered body of the present embodiment, a long-life cutting tool having high wear resistance and fracture resistance can be obtained.

[Embodiment 2]
A method for producing a ceramic sintered body according to another embodiment of the present invention includes cubic aluminum nitride powder, and nitrides, carbides, and oxides of metals of Groups 4A, 5A, and 6A of the periodic table And a step of mixing at least one metal compound powder selected from the group consisting of borides and solid solutions thereof, and a mixture obtained by the mixing at a temperature of 700 ° C. to 1500 ° C. of 2 GPa to 20 GPa And sintering with pressure. According to the method for producing a ceramic sintered body of the present embodiment, the ceramic sintered body of Embodiment 1 containing c-AlN (cubic aluminum nitride) that exists stably at normal pressure can be obtained.

(Mixing process of cubic aluminum nitride powder and metal compound powder)
The method for producing a ceramic sintered body according to the present embodiment includes firstly c-AlN (cubic aluminum nitride) powder and nitrides, carbides, and metals of Groups 4A, 5A, and 6A of the periodic table. And a step of mixing at least one metal compound powder selected from the group consisting of borides. By sintering the mixture of the c-AlN powder and the metal compound, a ceramic sintered body having high hardness and toughness can be obtained.

  Here, since the c-AlN powder is the c-AlN powder described in the first embodiment and the metal compound powder is the metal compound powder described in the first embodiment, the description thereof will not be repeated.

  In the method for producing a ceramic sintered body according to the present embodiment, in the mixing step, mixing the AlON (aluminum oxynitride) powder together with the c-AlN powder and the metal compound powder results in c-AlN being From the viewpoint of obtaining a ceramic sintered body in a more stable state, it is preferable. Here, since the AlON powder is the AlON powder described in the first embodiment, the description thereof will not be repeated.

  Further, in the mixing step, it is possible to mix h-AlN (hexagonal aluminum nitride) powder together with the c-AlN powder and the metal compound powder, so that ceramic sintering having high toughness and excellent fracture resistance. From the viewpoint of obtaining a body, it is preferable. Here, since the h-AlN powder is the h-AlN powder described in the first embodiment, the description thereof will not be repeated.

Further, in the mixing step, mixing the Al ₂ O ₃ (aluminum oxide) powder together with the c-AlN powder and the metal compound powder further produces a ceramic sintered body having high hardness and excellent oxidation resistance. From the viewpoint of obtaining, it is preferable. Here, Al ₂ O ₃ powder are the powder of Al ₂ O ₃ described in the first embodiment, description thereof will not be repeated.

That is, from the above viewpoint, in the mixing step, at least selected from the group consisting of the h-AlN powder, the AlON powder, and the Al ₂ O ₃ powder together with the c-AlN powder and the metal compound powder. It is preferable to mix any of them.

Here, the c-AlN powder, the metal compound powder, the h-AlN powder, the AlON powder, and the Al ₂ O ₃ powder are not particularly limited, but increase hardness and toughness and strength by increasing sinterability. From the viewpoint of obtaining the above, the particle size of the powder is preferably 5 nm or more and 10 μm or less, more preferably 100 nm or more and 5 μm or less.

Here, the mixing ratio of the c-AlN powder is not particularly limited, but is preferably 20% by volume or more and 80% by volume or less, and preferably 25% by volume or more and 50% by volume or more from the viewpoint of increasing the hardness and toughness of the obtained ceramic sintered body. Volume% or less is more preferable. The mixing ratio of the metal compound powder is preferably 20% by volume or more and 80% by volume or less, and more preferably 40% by volume or more and 75% by volume or less from the same viewpoint as described above. Further, the mixing ratio of the AlON powder is preferably 0.1% by volume or more and 20% by volume or less, and more preferably 5% by volume or more and 15% by volume or less from the viewpoint of obtaining a ceramic sintered body in which c-AlN is more stable. preferable. The mixing ratio of h-AlN powder is preferably 0.1% by volume or more and 50% by volume or less, preferably 5% by volume or more and 30% by volume from the viewpoint of obtaining a ceramic sintered body having high toughness and excellent fracture resistance. The following is more preferable. The mixing ratio of the Al ₂ O ₃ powder is preferably 0.1% by volume or more and 10% by volume or less, preferably 1% by volume or more and 7% by volume from the viewpoint of obtaining a ceramic sintered body having high hardness and excellent oxidation resistance. The following is more preferable.

  In the method for producing a ceramic sintered body according to the present embodiment, c-AlN (cubic aluminum nitride) used as a raw material is not particularly limited, but can be obtained by changing the crystal structure from h-AlN which is hexagonal. C-AlN that is cubic is preferably used. The method for changing the crystal structure from h-AlN to c-AlN is not particularly limited, but from the viewpoint of a high rate of change in crystal structure, a pressure of 10 GPa or more is applied to h-AlN powder using an ultrahigh pressure press or the like. Ultra-high pressure press method, shock compression method in which h-AlN powder is compressed by a shock wave generated by an explosive such as trinitrotoluene (TNT) with a pressure of 10 GPa or more and a pressurization time of 5 microseconds or less, and h-AlN powder is 1 MPa. A collision method in which the carrier gas is blown against the substrate in the atmospheric pressure processing chamber with the carrier gas at the above pressure, and the aerosol is blown against the substrate in the processing chamber which has been decompressed in an aerosol state by causing the h-AlN powder and the carrier gas to collide with the substrate. A position method or the like is preferably used.

  Here, in the case of the collision method, even if the carrier gas is 1 MPa (10 atm), since the powder is struck against the substrate in the processing chamber at atmospheric pressure at high speed, the powder is microscopically equivalent to a pressure of 10 GPa or more. In the aerosol deposition method, the flow rate of the carrier gas is 2 to 15 SLM from the viewpoint of the actual capacity of the apparatus (here, 1 SLM refers to the amount of 1 L (liter) of standard gas flowing per minute. ) And the particle speed is preferably 150 m / s or more.

  Here, the change rate (volume%) of the crystal structure from h-AlN to c-AlN in AlN (total of c-AlN and h-AlN) is the content (volume) of c-AlN after the change of the crystal structure. %) Minus the content (volume%) of c-AlN before the change of the crystal structure is expressed as a percentage of the content (volume%) of AlN. Here, the measuring method of each content rate of h-AlN and c-AlN in AlN is as above-mentioned.

(Sintering process of the mixture)
Next, the method for producing a ceramic sintered body of the present embodiment includes a step of sintering the mixture obtained by the above mixing at a temperature of 700 ° C. to 1500 ° C. and a pressure of 2 GPa to 20 GPa. By sintering at a temperature of 700 ° C. or more and 1500 ° C. or less, a ceramic sintered body containing c-AlN in a stable state can be obtained without changing the crystal structure to h-AlN that is more stable at normal pressure. From this viewpoint, the sintering temperature is preferably 800 ° C. or higher and 1300 ° C. or lower. In addition, by sintering at a pressure of 2 GPa or more and 20 GPa or less, reverse conversion from cubic crystal as a high pressure phase to hexagonal crystal as a normal pressure phase is suppressed, and a dense ceramic sintered body is obtained. From this viewpoint, the sintering pressure is preferably 5 GPa or more and 18 GPa or less.

Example 1
1. Mixing step c-AlN powder is processed from hexagonal crystal to cubic structure by treating h-AlN powder with an average particle size of 1.0 μm by ultra high pressure pressing method using ultra high pressure press under conditions of 15 GPa and 1400 ° C. What was changed into a crystal was used. The rate of change of the crystal structure from h-AlN to c-AlN was 70% by volume as measured by the XRD method. As the c-AlN powder, a sintered body treated under the above conditions was coarsely pulverized with a mortar and then finely pulverized to 2.0 μm or less with a bead mill. As the metal compound powder, TiN powder having an average particle size of 1.0 μm was used.

  After adding metal compound powder (TiN powder), c-AlN powder and h-AlN powder to the ball mill at a mixing ratio of 50 vol%, 35 vol% and 15 vol%, respectively, and further adding ethanol as a dispersion solvent, These were mixed uniformly. The obtained mixed slurry was dried to obtain a mixed powder as a raw material. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was filled in a tantalum capsule and sintered in an N ₂ (nitrogen) gas atmosphere at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. . The obtained ceramic sintered body contains metal compound (TiN), c-AlN, and h-AlN, as measured by mapping by AES (Auger electron spectroscopy) method and XRD (X-ray diffraction) method. The contents of were 50% by volume, 30% by volume and 20% by volume, respectively. The oxygen content (atomic%) in c-AlN was 0.4 atomic% as measured by AES method. The results are summarized in Table 2.

3. Cutting test The obtained ceramic sintered body was cut with a laser and then finished to produce a cutting tool having a tip nose R of 0.8 mm. Using the produced cutting tool, the cutting speed is 400 m / min, the cutting amount is 0.2 mm, and the feeding amount is 0.1 mm / rev (where 1 mm / rev indicates a feeding amount of 1 mm per rotation). ) And no cutting oil, a steel (S45C) cutting test was performed, and the amount of wear on the flank of the cutting tool after cutting 1 km was measured. The amount of wear of the cutting tool in this example was 52 μm. The results are summarized in Table 2.

(Example 2)
1. Mixing step c-AlN powder has a hexagonal crystal structure treated by shock compression using trinitrotoluene (TNT) with h-AlN powder having an average particle size of 1.0 μm as an explosive under conditions of 20 GPa and 1000 ° C. What changed from a crystal to a cubic crystal was used. The rate of change of the crystal structure from h-AlN to c-AlN was 50% by volume. As the metal compound powder, TiN powder having an average particle size of 1.0 μm was used.

  As a raw material, metal compound powder (TiN powder), c-AlN powder and h-AlN powder were mixed in the same manner as in Example 1 with mixing ratios of 20% by volume, 40% by volume and 40% by volume, respectively. Of mixed powder was obtained. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TiN), c-AlN and h-AlN, and their contents were 20% by volume, 35% by volume and 45% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.1 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 55 μm. The results are summarized in Table 2.

(Example 3)
1. Mixing step The c-AlN powder is obtained by spraying an h-AlN powder having an average particle diameter of 1.0 μm onto a quartz substrate in a processing chamber having an atmospheric pressure of 0.1 MPa with N ₂ (nitrogen) gas as a carrier gas. The crystal structure was changed from hexagonal to cubic by the collision method for collision. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, TiN powder having an average particle size of 1.0 μm was used.

  Metal compound powder (TiN powder) and c-AlN powder were mixed in the same manner as in Example 1 with mixing ratios of 20% by volume and 80% by volume, respectively, to obtain a mixed powder as a raw material. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TiN) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.4 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 51 μm. The results are summarized in Table 2.

Example 4
1. Mixing step The c-AlN powder is formed by applying 10 SLM to a quartz substrate in a processing chamber whose pressure is reduced to 300 Pa by using an aerosol state of an H-AlN powder having an average particle diameter of 1.0 μm and a carrier gas N ₂ (nitrogen) gas. The crystal structure was changed from a hexagonal crystal to a cubic crystal by an aerosol deposition method in which a collision was caused by spraying at a flow rate and a particle velocity of 200 m / s. The rate of change of the crystal structure from h-AlN to c-AlN was 80% by volume. As the metal compound powder, TiN powder having an average particle size of 1.0 μm was used.

  As a raw material, metal compound powder (TiN powder), c-AlN powder and h-AlN powder were mixed in the same manner as in Example 1 with mixing ratios of 70% by volume, 24% by volume and 6% by volume, respectively. Of mixed powder was obtained. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TiN), c-AlN and h-AlN, and their contents were 70% by volume, 20% by volume and 10% by volume, respectively. The oxygen content (atomic%) in c-AlN was 0.9 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 54 μm. The results are summarized in Table 2.

(Example 5)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, TiN powder having an average particle size of 1.0 μm was used. As the h-AlN powder, one having an average particle diameter of 1.0 μm was used.

  By mixing the metal compound powder (TiN powder), c-AlN powder and h-AlN powder in the same manner as in Example 1 with mixing ratios of 25 vol%, 30 vol% and 45 vol%, respectively, as raw materials Of mixed powder was obtained. The results are summarized in Table 1.

2. Sintering Step The mixed powder obtained above was sintered at 8 GPa and 800 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TiN), c-AlN and h-AlN, and their contents were 25% by volume, 25% by volume and 50% by volume, respectively. The oxygen content (atomic%) in c-AlN was 0.9 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 63 μm. The results are summarized in Table 2.

(Example 6)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, TiN powder having an average particle size of 1.0 μm was used. AlON powder having an average particle diameter of 1.0 μm was used.

  Metal compound powder (TiN powder), c-AlN powder, and AlON powder were mixed in the same manner as in Example 1 with mixing ratios of 40% by volume, 40% by volume, and 20% by volume, respectively. A powder was obtained. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1500 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contains a metal compound (TiN), c-AlN, h-AlN and AlON, and their contents are 40% by volume, 35% by volume, 5% by volume and 20% by volume, respectively. Met. The oxygen content (atomic%) in c-AlN was 1.7 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 31 μm. The results are summarized in Table 2.

(Example 7)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, TiN powder having an average particle size of 1.0 μm was used. Al ₂ O ₃ powder having an average particle diameter of 1.0 μm was used.

By mixing the metal compound powder (TiN powder), c-AlN powder and Al ₂ O ₃ powder in the same manner as in Example 1 with mixing ratios of 40% by volume, 47% by volume and 13% by volume, respectively, As a mixed powder was obtained. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TiN), c-AlN, AlON and AlON, and their contents were 40 vol%, 45 vol%, 5 vol% and 10 vol%, respectively. It was. The oxygen content (atomic%) in c-AlN was 4.9 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 56 μm. The results are summarized in Table 2.

(Example 8)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, TiN powder having an average particle size of 1.0 μm was used.

  Metal compound powder (TiN powder) and c-AlN powder were mixed in the same manner as in Example 1 with mixing ratios of 20% by volume and 80% by volume, respectively, to obtain a mixed powder as a raw material. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 700 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TiN) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.3 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 57 μm. The results are summarized in Table 2.

Example 9
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, TiN powder having an average particle size of 1.0 μm was used.

  Metal compound powder (TiN powder) and c-AlN powder were mixed in the same manner as in Example 1 with mixing ratios of 20% by volume and 80% by volume, respectively, to obtain a mixed powder as a raw material. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 2 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TiN), c-AlN and h-AlN, and their contents were 20% by volume, 60% by volume and 20% by volume, respectively. The oxygen content (atomic%) in c-AlN was 3.5 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 55 μm. The results are summarized in Table 2.

(Example 10)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, TiN powder having an average particle size of 1.0 μm was used.

  Metal compound powder (TiN powder) and c-AlN powder were mixed in the same manner as in Example 1 with mixing ratios of 20% by volume and 80% by volume, respectively, to obtain a mixed powder as a raw material. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 20 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TiN) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 0.5 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 32 μm. The results are summarized in Table 2.

(Example 11)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, a ZrN powder having an average particle diameter of 1.0 μm was used.

  A mixed powder as a raw material was obtained by mixing the metal compound powder (ZrN powder) and the c-AlN powder in the same manner as in Example 1 with the mixing ratios being 20% by volume and 80% by volume, respectively. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (ZrN) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.6 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 61 μm. The results are summarized in Table 2.

(Example 12)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, HfN powder having an average particle diameter of 1.0 μm was used.

  A mixed powder as a raw material was obtained by mixing the metal compound powder (HfN powder) and the c-AlN powder in the same manner as in Example 1 with the mixing ratios being 20% by volume and 80% by volume, respectively. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (HfN) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.4 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 64 μm. The results are summarized in Table 2.

(Example 13)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, VN powder having an average particle diameter of 1.0 μm was used.

  A mixed powder as a raw material was obtained by mixing the metal compound powder (VN powder) and the c-AlN powder in the same manner as in Example 1 with the mixing ratios being 20% by volume and 80% by volume, respectively. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (VN) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.7 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 70 μm. The results are summarized in Table 2.

(Example 14)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, NbN powder having an average particle diameter of 1.0 μm was used.

  A mixed powder as a raw material was obtained by mixing the metal compound powder (NbN powder) and the c-AlN powder in the same manner as in Example 1 with the mixing ratios being 20% by volume and 80% by volume, respectively. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (NbN) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.6 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 73 μm. The results are summarized in Table 2.

(Example 15)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, TaN powder having an average particle diameter of 1.0 μm was used.

  A mixed powder as a raw material was obtained by mixing the metal compound powder (TaN powder) and the c-AlN powder in the same manner as in Example 1 with the mixing ratios being 20% by volume and 80% by volume, respectively. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TaN) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.1 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 66 μm. The results are summarized in Table 2.

(Example 16)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, CrN powder having an average particle diameter of 1.0 μm was used.

  A mixed powder as a raw material was obtained by mixing the metal compound powder (CrN powder) and the c-AlN powder in the same manner as in Example 1 with the mixing ratios being 20% by volume and 80% by volume, respectively. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (CrN) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.8 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 62 μm. The results are summarized in Table 2.

(Example 17)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, MoN powder having an average particle diameter of 1.0 μm was used.

  A mixed powder as a raw material was obtained by mixing the metal compound powder (MoN powder) and the c-AlN powder in the same manner as in Example 1 with the mixing ratios being 20% by volume and 80% by volume, respectively. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (MoN) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.5 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 64 μm. The results are summarized in Table 2.

(Example 18)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, WN powder having an average particle diameter of 1.0 μm was used.

  Metal compound powder (WN powder) and c-AlN powder were mixed in the same manner as in Example 1 with mixing ratios of 20% by volume and 80% by volume, respectively, to obtain a mixed powder as a raw material. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (WN) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.6 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 62 μm. The results are summarized in Table 2.

(Example 19)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, TiC powder having an average particle diameter of 1.0 μm was used.

  A mixed powder as a raw material was obtained by mixing the metal compound powder (TiC powder) and the c-AlN powder in the same manner as in Example 1 with the mixing ratio of 20% by volume and 80% by volume, respectively. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TiC) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.3 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 51 μm. The results are summarized in Table 2.

(Example 20)
1. Mixing step The c-AlN powder was the same as in Example 3, except that the crystal structure of the h-AlN powder having an average particle diameter of 1.0 μm was changed from hexagonal to cubic. The rate of change of the crystal structure from h-AlN to c-AlN was 100% by volume. As the metal compound powder, TiB ₂ powder having an average particle diameter of 1.0 μm was used.

A mixed powder as a raw material was obtained by mixing the metal compound powder (TiB ₂ powder) and the c-AlN powder in the same manner as in Example 1 with the mixing ratios being 20% by volume and 80% by volume, respectively. . The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TiB ₂ ) and c-AlN, and their contents were 20% by volume and 80% by volume, respectively. The oxygen content (atomic%) in c-AlN was 1.9 atomic%. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this example was 75 μm. The results are summarized in Table 2.

(Comparative Example 1)
A cutting tool was prepared from a cemented carbide containing 50% by volume of WC and 50% by volume of Co in the same manner as in Example 1 to perform a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this comparative example was 244 μm. The results are summarized in Tables 1 and 2.

(Comparative Example 2)
A cutting tool was prepared from an alumina ceramic containing 95% by volume of Al ₂ O ₃ and 5% by volume of Y ₂ O _{3 in the same} manner as in Example 1 and a cutting test was performed. The amount was measured. The amount of wear of the cutting tool in this comparative example was 169 μm. The results are summarized in Tables 1 and 2.

(Comparative Example 3)
1. Mixing Step h-AlN powder having an average particle size of 1.0 μm was used. As the metal compound powder, TiN powder having an average particle size of 1.0 μm was used.

  A mixed powder as a raw material was obtained by mixing the metal compound powder (TiN powder) and the h-AlN powder in the same manner as in Example 1 with the mixing ratios being 20% by volume and 80% by volume, respectively. The results are summarized in Table 1.

2. Sintering process The mixed powder obtained above was sintered at 8 GPa and 1000 ° C. for 20 minutes to obtain a ceramic sintered body. The obtained ceramic sintered body contained a metal compound (TiN) and h-AlN, and their contents were 20% by volume and 80% by volume, respectively. The results are summarized in Table 2.

3. Cutting test From the obtained ceramic sintered body, in the same manner as in Example 1, a cutting tool was produced and subjected to a cutting test, and the amount of wear on the flank of the cutting tool was measured. The amount of wear of the cutting tool in this comparative example was 152 μm. The results are summarized in Table 2.

  Referring to Tables 1 and 2, the cutting tool made from a cemented carbide containing 50% by volume WC and 50% by volume Co had a wear amount of 244 μm (Comparative Example 1), and the cutting made from an alumina ceramic. The amount of wear of the tool was 169 μm (Comparative Example 2) and the amount of wear of the cutting tool made from the ceramic sintered body not containing c-AlN was 152 μm (Comparative Example 3), both of which were large. The amount of wear of the cutting tool produced from the ceramic sintered body containing such c-AlN was extremely small, 31 to 75 μm (Examples 1 to 20).

  As described above, according to the ceramic sintered body and the manufacturing method thereof according to the present invention, a ceramic sintered body having high hardness and toughness can be obtained by including c-AlN, and the amount of wear from the ceramic sintered body is obtained. A cutting tool with a very small is obtained.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The ceramic sintered body according to the present invention can be widely used for a cutting tool, and can form a smooth cutting surface on the surface of a work material over a long distance. In particular, it can be suitably used for a cutting tool for cutting a work material having high hardness, a work material made of a heat-resistant alloy, or a work material containing an iron-based material.

Claims (13)

  Cubic aluminum nitride and at least one metal compound selected from the group consisting of nitrides, carbides, oxides, borides and solid solutions of metals in groups 4A, 5A and 6A of the periodic table And a ceramic sintered body.   2. The ceramic sintered body according to claim 1, wherein a content of the cubic aluminum nitride is 20 volume% or more and 80 volume% or less.   The ceramic sintered body according to claim 1 or 2, wherein the cubic aluminum nitride contains oxygen in an amount of 0.1 atomic% to 5 atomic%.   The ceramic sintered body according to any one of claims 1 to 3, wherein the ceramic sintered body further includes at least one selected from the group consisting of hexagonal aluminum nitride, aluminum oxynitride, and aluminum oxide.   The ceramic sintered body according to claim 4, wherein the content of the hexagonal aluminum nitride is 0.1 volume% or more and 50 volume% or less.   The ceramic sintered body according to claim 4, wherein the content of the aluminum oxynitride is 0.1% by volume or more and 20% by volume or less.   The ceramic sintered body according to claim 4, wherein the content of the aluminum oxide is 0.1% by volume or more and 10% by volume or less.   At least one metal selected from the group consisting of cubic aluminum nitride powder and nitrides, carbides, oxides, borides and solid solutions of metals of Group 4A, Group 5A and Group 6A of the periodic table A method for producing a ceramic sintered body comprising: mixing a compound powder; and sintering the mixture obtained by the mixing at a temperature of 700 ° C. to 1500 ° C. at a pressure of 2 GPa to 20 GPa.   The method for producing a ceramic sintered body according to claim 8, further comprising mixing aluminum oxynitride powder in the mixing step.   The ceramic sintered body according to claim 8 or 9, wherein the cubic aluminum nitride powder is obtained by changing the crystal structure of the hexagonal aluminum powder by applying a pressure of 10 GPa or more to the hexagonal aluminum nitride powder. Body manufacturing method.   The cubic aluminum nitride powder is obtained by changing the crystal structure of the hexagonal aluminum powder by a method of shock compressing the hexagonal aluminum nitride powder with a shock wave having a pressure of 10 GPa or more and a pressing time of 5 microseconds or less. A method for producing a ceramic sintered body according to claim 8 or 9.   The cubic aluminum nitride powder is formed by spraying the hexagonal aluminum nitride powder onto a substrate in a processing chamber at an atmospheric pressure with a carrier gas having a pressure of 1 MPa or more, and by impact when the hexagonal aluminum nitride powder collides with the substrate, The method for producing a ceramic sintered body according to claim 8 or 9, wherein the crystal structure is changed.   The cubic aluminum nitride powder is sprayed onto the substrate in a reduced pressure processing chamber with the hexagonal aluminum nitride powder and the carrier gas in an aerosol state, and the crystal of the hexagonal aluminum nitride powder is produced by impact when colliding with the substrate. The method for producing a ceramic sintered body according to claim 8 or 9, wherein the structure is changed.