CN112830792A - High-hardness hafnium-based ternary solid solution boride ceramic and preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of ceramic materials, and discloses a high-hardness hafnium-based ternary solid solution boride ceramic as well as a preparation method and application thereof. The boride ceramic has a molecular formula of (Hf)_aMe1_bMe2_c)B₂Wherein a is more than or equal to 0.1 and less than or equal to 0.9 and 0<b<0.9，0<c<0.9, and a + b + c is 1; me1 and Me2 are Zr, Ta or Ti, the ceramics being obtained by reacting HfO₂Me1 and Me2 oxide, B₄C. Adding carbon powder into a solvent, carrying out ball milling to obtain mixed powder, carrying out die pressing to obtain a blank, putting the blank into a graphite crucible, heating to 1400-1600 ℃, carrying out heat preservation, and carrying out vacuum heat treatment to obtain hafnium-based ternary solid solution boride powder; and (3) heating the ternary solid solution boride powder to 1000-1400 ℃ by adopting spark plasma sintering, filling the ternary solid solution boride powder into a protective atmosphere, heating to 1900-2100 ℃, and calcining under the pressure of 10-100 MP to obtain the ternary solid solution boride powder.

Description

High-hardness hafnium-based ternary solid solution boride ceramic and preparation method and application thereof

Technical Field

The invention belongs to the technical field of ceramic materials, and particularly relates to a high-hardness hafnium-based ternary solid solution boride ceramic as well as a preparation method and application thereof.

Background

Hafnium diboride (Hf)B₂) As ultra-high temperature ceramics (UHTC), attention has been paid to the ultra-high temperature ceramics (UHTC) because of their extremely high melting point (3380 ℃ C.), high Young's modulus (500 GPa), high hardness (18-21GPa), excellent high temperature performance and chemical stability. HfB2 ceramic is expected to be useful in the supersonic aerospace industry and high temperature parts (>3000 ℃ C., etc. Compared with single-component materials, the preparation of the solid solution ceramic can effectively improve the sinterability of boride ceramic and overcome the challenge of densification. The solid solution material has better mechanical property and thermal stability. Solid solution of MeB2(Me ═ Zr/Ta/Ti) greatly improved HfB₂Densification, texture and mechanical properties of the ceramic. Therefore, the solid solution ceramic has wide application prospect in the high-temperature field. Very few reports have been made on the synthesis of ternary solid solution boride powders and sintered ceramics. The literature reports the preparation of single-phase (Ta) by the molten salt method_1/3Nb_{1/ 3}Ti_1/3)B₂The powder has a diameter of 20 to 40nm and a length of 100 to 200nm, and is in the shape of a nanorod. However, this method cannot synthesize a single phase (Hf)_1/3Zr_1/3Ti_1/3)B₂Powder of boride phase (TiB)₂) Is still present. In addition, the mechanical properties of the ternary boride and the influence of solid solution elements on the sintering properties thereof have not been determined.

Disclosure of Invention

In order to solve the defects and shortcomings of the prior art, a hafnium-based ternary solid solution boride ceramic with high hardness is provided. The ceramic has the advantages of uniform solid solution phase, stable component and high hardness.

The invention also aims to provide a preparation method of the hafnium-based ternary solid solution boride ceramic.

The invention further aims to provide application of the hafnium-based ternary solid solution boride ceramic.

The purpose of the invention is realized by the following technical scheme:

the high-hardness hafnium-based ternary solid solution boride ceramic is characterized in that the molecular formula of the boride ceramic is (Hf)_aMe1_bMe2_c)B₂Wherein a is more than or equal to 0.1 and less than or equal to 0.9 and 0<b<0.9，0<c<0.9, and a +b + c is 1; me1 and Me2 are Zr, Ta or Ti, and the ceramic is HfO₂Me oxide ZrO₂、Ta₂O₅、TiO₂Any two of them, B₄C. Adding carbon powder into a solvent, ball-milling and mixing to obtain mixed powder, pressing the mixed powder to obtain a blank, putting the blank into a graphite crucible, heating to 1400-1600 ℃, preserving heat, and carrying out vacuum heat treatment to obtain (Hf)_aMe1_bMe2_c)B₂Hafnium-based ternary solid solution boride powder; and (3) heating the ternary solid solution boride powder to 1000-1400 ℃ by adopting spark plasma sintering, filling the ternary solid solution boride powder into a protective atmosphere, heating to 1900-2100 ℃, and calcining under the pressure of 10-100 MP to obtain the ternary solid solution boride powder.

Preferably, the (Hf)_aMe1_bMe2_c)B₂The hafnium-based ternary solid solution boride powder has a purity of 95.0 to 99.9 wt% and a particle size of 0.1 to 1 μm.

Preferably, the (Hf)_aMe1_bMe2_c)B₂The hafnium-based ternary solid solution boride powder has an oxygen content of 0.01 to 5 wt% and a carbon content of 0.01 to 5 wt%.

Preferably, the HfO₂、ZrO₂、Ta₂O₅And TiO₂The purity of the particles is 99.0-99.9 wt%, and the particle size is 0.1-10 μm; b is₄The purity of the C powder and the purity of the carbon powder are both 97-99.99 wt.%, and the particle size is 1-1.5 mu m.

Preferably, the grain size of the hafnium-based ternary solid solution boride ceramic is 2.45-6.62 mu m, and the relative density is 94-98%; the hardness of the hafnium-based ternary solid solution boride ceramic is 28-35 GPa.

Preferably, the solvent is ethanol, propanol, methanol or acetone.

Preferably, the protective atmosphere is N₂Or Ar.

Preferably, the heating rate of heating to 1400-1600 ℃ is 5-15 ℃/min; the heat preservation time is 0.5-2 h; the heating rate is 100-400 ℃/min when the temperature is raised to 1000-1400 ℃; the heating rate is 100-400 ℃/min when the temperature is raised to 1900-2100 ℃.

The preparation method of the high-hardness hafnium-based ternary solid solution boride ceramic comprises the following specific steps:

s1, mixing HfO₂Me oxide ZrO₂、Ta₂O₅、TiO₂Any two of them, B₄C. Adding a solvent and a ball milling medium into carbon powder, mixing for 20-40 h on a ball mill, and drying to obtain mixed powder;

s2, placing the blank after the mixed powder is molded into a graphite crucible for vacuum heat treatment, heating to 1400-1600 ℃ at the speed of 5-15 ℃/min, and preserving heat for 0.5-2 h to obtain hafnium-based ternary solid solution boride powder;

s3, placing the hafnium-based ternary solid solution boride powder into a graphite mold, heating to 1000-1400 ℃ at the speed of 100-400 ℃/min by adopting discharge plasma sintering, filling protective atmosphere, heating to 1900-2100 ℃ at the speed of 100-400 ℃/min, preserving heat for 10-30 min, and pressurizing to 10-100 MPa for calcination to obtain the hafnium-based ternary solid solution boride powder ceramic.

The high-hardness hafnium-based ternary solid solution boride ceramic is applied to the field of preparation of superhard grinding tool materials.

The hafnium-based ternary solid solution boride ceramic of the invention is prepared from three metal oxides B₄C and C are taken as raw materials, and are subjected to boron thermal carbon thermal reduction reaction to prepare (Hf)_aMe1_bMe2_c)B₂The method for preparing the hafnium-based ternary solid solution boride powder through in-situ solid solution is easier to form a single phase, has small powder particle size, high purity and large sintering driving force, and is easier to prepare high-performance (Hf) boride powder_aMe1_bMe2_c)B₂Hafnium-based ternary solid solution boride ceramics. And can be regulated and controlled according to different solid solution elements (Hf)_aMe1_bMe2_c)B₂The performance of the hafnium-based ternary solid solution boride ceramic.

Compared with the prior art, the invention has the following beneficial effects:

1. prepared by the invention of (Hf)_aMe1_bMe2_c)B₂Hafnium-based ternary solid solution boride ceramic powder obtainable byIn-situ synthesizing single-phase solid solution powder by a borothermic carbothermic method; prepared (Hf)_aMe1_bMe2_c)B₂Hafnium-based ternary solid solution boride ceramic, which can be controlled by solid solution of different elements compared to single-phase boride ceramic or binary boride ceramic (Hf)_aMe1_bMe2_c)B₂The performance of the hafnium-based ternary solid solution boride ceramic.

2. Prepared by the invention of (Hf)_aMe1_bMe2_c)B₂The hafnium-based ternary solid solution boride ceramic powder has small particle size (0.1-1 mu m), high purity and large sintering driving force, is easy to burn out single-phase solid solution ceramic, and improves the ceramic performance.

3. (Hf) prepared by the method of the present invention_aMe1_bMe2_c)B₂Hafnium-based ternary solid solution boride ceramic having TaB solid-dissolved therein₂Although finer powders can be obtained, it is noteworthy that TaB in solid solution₂The finer powder of (1) is not easy to sinter to be dense, but instead dissolves TiB2 (Hf)_aMe1_bMe2_c)B₂The hafnium-based ternary solid solution boride ceramic is more compact and has higher hardness.

4. Prepared by the invention of (Hf)_aMe1_bMe2_c)B₂Hafnium-based ternary solid solution boride ceramic due to TaB₂Has a large atomic radius, so that the crystal lattice distortion is large when the TaB is dissolved in a solid solution, and the TaB is dissolved in a solid solution₂Of (Hf)_aMe1_bMe2_c)B₂The hafnium-based ternary solid solution boride ceramic is less dense but due to TaB₂And (Hf)_aMe1_bMe2_c)B₂The hafnium-based ternary solid solution boride ceramic powder has good compatibility, and TaB in solid solution₂Of (Hf)_aMe1_bMe2_c)B₂The particle size of the hafnium-based ternary solid solution boride ceramic powder is finer.

5. Prepared by the invention of (Hf)_aMe1_bMe2_c)B₂Hafnium-based ternary solid solution boride ceramics due to TiB₂Has higher hardness even if TiB is dissolved in solution₂Of (Hf)_aMe1_bMe2_c)B₂The hafnium-based ternary solid solution boride ceramic powder is coarse, but solid solution TiB₂Of (Hf)_aMe1_bMe2_c)B₂The density of the hafnium-based ternary solid solution boride ceramic is 94-98%, and the hardness is improved to 28-35 GPa.

Description of the drawings

FIG. 1 shows (Hf) obtained in example 1_1/3Zr_1/3Ti_1/3)B₂Fracture morphology of hafnium-based ternary solid solution boride ceramic;

FIG. 2 shows (Hf) obtained in example 1_1/3Zr_1/3Ti_1/3)B₂Corrosion photograph of polished surface of hafnium-based ternary solid solution boride ceramic

FIG. 3 is (Hf) obtained in example 2_1/3Ta_1/3Ti_1/3)B₂Fracture morphology of hafnium-based ternary solid solution boride ceramic;

FIG. 4 shows (Hf) obtained in example 2_1/3Ta_1/3Ti_1/3)B₂Corrosion photograph of polished surface of hafnium-based ternary solid solution boride ceramic

Detailed Description

The following examples are presented to further illustrate the present invention and should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Example 1

1. With HfO₂(purity of powder 99%, particle diameter 1 μm), ZrO₂(purity of powder 99.8%, particle diameter 1 μm), TiO₂(purity of powder 99%, particle diameter 0.5 μm), and B₄C (purity of powder 99.9%, particle size 0.5 μm), carbon powder (purity of powder 99%, particle size 0.8 μm) as raw material, ethanol as solvent, and Si₄N₃Mixing the mixture serving as a ball milling medium on a ball mill for 24 hours, and drying to obtain mixed powder;

2. placing the green body of the mixed powder after mould pressing into a graphite crucible,heating to 1600 deg.C at a rate of 10 deg.C/min, maintaining for 1h, and vacuum heat treating to obtain (Hf)_1/3Zr_1/3Ti_1/3)B₂Hafnium-based ternary solid solution boride ceramic powder.

3. Will (Hf)_1/3Zr_1/3Ti_1/3)B₂Putting hafnium-based ternary solid solution boride ceramic powder into a graphite mold, heating to 1000 ℃ at the speed of 150 ℃/min by adopting spark plasma sintering, filling Ar protective atmosphere, heating to 2000 ℃ at the speed of 150 ℃/min, preserving heat for 10min, pressurizing to 30MPa, and calcining to obtain (Hf) (Hf is prepared_1/3Zr_1/3Ti_1/3)B₂Hafnium-based ternary solid solution boride ceramics.

(Hf) (0.03 wt% of carbon content in solid solution powder, 0.01 wt% of oxygen content in solid solution powder, measured by laser particle size analysis) in the solid solution powder of this example_{1/ 3}Zr_1/3Ti_1/3)B₂The hafnium-based ternary solid solution boride ceramic has a grain size of 6.62 μm, a relative density of 98%, and a hardness of 35 GPa.

FIG. 1 shows (Hf) obtained in example 1_1/3Zr_1/3Ti_1/3)B₂Fracture morphology of hafnium-based ternary solid solution boride ceramic; as can be seen from FIG. 1 (Hf)_1/3Zr_1/3Ti_1/3)B₂The hafnium-based ternary solid solution boride ceramic is more compact in sintering, basically has no pores and has a relative density of 98%. FIG. 2 shows (Hf) obtained in example 1_1/3Zr_1/3Ti_1/3)B₂And (3) corrosion pictures of the polished surface of the hafnium-based ternary solid solution boride ceramic. As can be seen from FIG. 2, the crystal grain size was 6.62 μm, and the anisotropy of the crystal grains was improved in the form of long rod-like crystal grains (Hf)_1/3Zr_1/3Ti_1/3)B₂The hafnium-based ternary solid solution boride ceramic has the performance that the hardness is 35 GPa.

Example 2

1. With HfO₂(purity of powder 99%, particle diameter 1 μm), Ta₂O₅(purity of powder 99.8%, particle diameter 1 μm), TiO₂(purity of powder 99%, particle diameter 0.5. mum), and B)₄C (purity of powder 99.9%, particle size 0.5 μm), carbon powder (purity of powder 99%, particle size 0.8 μm) as raw material, ethanol as solvent, and Si₄N₃Mixing the mixture serving as a ball milling medium on a ball mill for 24 hours, and drying to obtain mixed powder;

2. putting the blank after the mixed powder mould pressing into a graphite crucible, heating to 1600 ℃ at the speed of 10 ℃/min, preserving the heat for 1h, and carrying out vacuum heat treatment to obtain (Hf)_1/3Ta_1/3Ti_1/3)B₂Hafnium-based ternary solid solution boride ceramic powder.

3. Will (Hf)_1/3Ta_1/3Ti_1/3)B₂Putting hafnium-based ternary solid solution boride ceramic powder into a graphite mold, heating to 1000 ℃ at the speed of 150 ℃/min by adopting spark plasma sintering, filling Ar protective atmosphere, heating to 2000 ℃ at the speed of 150 ℃/min, preserving heat for 10min, pressurizing to 30MPa, and calcining to obtain (Hf) (Hf is prepared_1/3Ta_1/3Ti_1/3)B₂Hafnium-based ternary solid solution boride ceramics.

(Hf, 0.03 wt% in terms of the particle diameter of the solid solution powder in this example measured by laser particle size analysis, 0.26 μm in terms of the oxygen content of the solid solution powder measured by a carbon-oxygen analyzer, and 0.01 wt% in terms of the carbon content of the solid solution powder_{1/ 3}Ta_1/3Ti_1/3)B₂The hafnium-based ternary solid solution boride ceramic has a grain size of 2.45 μm, a relative density of 94% and a hardness of 28 GPa.

FIG. 3 is (Hf) obtained in example 2_1/3Ta_1/3Ti_1/3)B₂Fracture morphology of hafnium-based ternary solid solution boride ceramic; as can be seen from FIG. 3 (Hf)_1/3Ta_1/3Ti_1/3)B₂The hafnium-based ternary solid solution boride ceramic has many pores and a relative density of 94%. FIG. 4 shows (Hf) obtained in example 2_1/3Ta_1/3Ti_1/3)B₂And (3) corrosion photos of the hafnium-based ternary solid solution boride ceramic polished surface. As can be seen from FIG. 4, the grain size is 2.45 μm, and although the ceramic grain size is finer, due to TaB₂The hardness of (2) is low, the compactness is not high, and the hardness is 28 GPa.

Example 3

1. With HfO₂(purity of powder 99%, particle diameter 2 μm), ZrO₂(purity of powder 99.8%, particle diameter 2 μm), Ta₂O₅(purity of powder 99%, particle diameter 2 μm), and B₄C (purity of powder 99.9%, particle size 2 μm), carbon powder (purity of powder 99%, particle size 2 μm) as raw material, ethanol as solvent, and Si₄N₃Mixing the mixture serving as a ball milling medium on a ball mill for 24 hours, and drying to obtain mixed powder;

2. putting the blank after the mixed powder mould pressing into a graphite crucible, heating to 1600 ℃ at the speed of 10 ℃/min, preserving the heat for 1h, and carrying out vacuum heat treatment to obtain (Hf)_1/3Zr_1/3Ta_1/3)B₂Hafnium-based ternary solid solution boride ceramic powder.

3. Will (Hf)_1/3Zr_1/3Ta_1/3)B₂Putting hafnium-based ternary solid solution boride ceramic powder into a graphite mold, heating to 1000 ℃ at the speed of 150 ℃/min by adopting spark plasma sintering, filling Ar protective atmosphere, heating to 2000 ℃ at the speed of 150 ℃/min, preserving heat for 10min, pressurizing to 30MPa, and calcining to obtain (Hf) (Hf is prepared_1/3Zr_1/3Ta_1/3)B₂Hafnium-based ternary solid solution boride ceramics.

(Hf) (0.02 wt% of carbon content in solid solution powder, 0.02 wt% of oxygen content in solid solution powder, and 0.46 μm of powder particle size in solid solution powder according to the example measured by laser particle size analysis_1/3Zr_{1/ 3}Ta_1/3)B₂The hafnium-based ternary solid solution boride ceramic has a grain size of 3.23 μm, a relative density of 95%, and a hardness of 30 GPa.

Example 4

1. With HfO₂(purity of powder 99%, particle diameter 1 μm), ZrO₂(purity of powder 99.8%, particle diameter 1 μm), TiO₂(purity of powder 99%, particle diameter 0.5 μm), and B₄C (purity of powder 99.9%, particle size 0.5 μm), carbon powder (purity of powder 99%, particle size 0.8 μm) as raw material, ethanol as solvent, and Si₄N₃Is ball millingMixing the medium in a ball mill for 24 hours, and drying to obtain mixed powder;

2. putting the blank after the mixed powder mould pressing into a graphite crucible, heating to 1600 ℃ at the speed of 10 ℃/min, preserving the heat for 1h, and carrying out vacuum heat treatment to obtain (Hf)_1/10Zr_0.45Ti_0.45)B₂Hafnium-based ternary solid solution boride ceramic powder.

3. Will (Hf)_1/10Zr_0.45Ti_0.45)B₂Putting hafnium-based ternary solid solution boride ceramic powder into a graphite mold, heating to 1000 ℃ at the speed of 150 ℃/min by adopting spark plasma sintering, filling Ar protective atmosphere, heating to 2000 ℃ at the speed of 150 ℃/min, preserving heat for 20min, pressurizing to 40MPa, and calcining to obtain (Hf) (Hf is prepared_1/10Zr_0.45Ti_0.45)B₂Hafnium-based ternary solid solution boride ceramics.

(Hf, 0.03 wt% in terms of the particle diameter of the solid solution powder in this example measured by laser particle size analysis, 0.45 μm in terms of the oxygen content of the solid solution powder measured by a carbon-oxygen analyzer, and 0.1 wt% in terms of the carbon content of the solid solution powder_{1/ 10}Zr_0.45Ti_0.45)B₂The hafnium-based ternary solid solution boride ceramic has a grain size of 4.67 μm, a relative density of 97%, and a hardness of 34 GPa.

Example 5

1. With HfO₂(purity of powder 99%, particle diameter 4 μm), Ta₂O₅(purity of powder 99.8%, particle size 4 μm), TiO₂(purity of powder 99%, particle diameter 4 μm), and B₄C (purity of powder 99.9%, particle size 4 μm), carbon powder (purity of powder 99%, particle size 4 μm) as raw material, ethanol as solvent, and Si₄N₃Mixing the mixture serving as a ball milling medium on a ball mill for 24 hours, and drying to obtain mixed powder;

2. putting the blank after the mixed powder mould pressing into a graphite crucible, heating to 1600 ℃ at the speed of 10 ℃/min, preserving the heat for 2h, and carrying out vacuum heat treatment to obtain (Hf)_1/4Ta_1/4Ti_1/2)B₂Hafnium-based ternary solid solution boride ceramic powder.

3. Will (Hf)_1/4Ta_1/4Ti_1/2)B₂Putting hafnium-based ternary solid solution boride ceramic powder into a graphite mold, heating to 1000 ℃ at the speed of 200 ℃/min by adopting spark plasma sintering, filling Ar protective atmosphere, heating to 2000 ℃ at the speed of 150 ℃/min, preserving heat for 30min, pressurizing to 50MPa, and calcining to obtain (Hf) (Hf is prepared_1/4Ta_1/4Ti_1/2)B₂Hafnium-based ternary solid solution boride ceramics.

(Hf, 0.03 wt% in terms of the particle diameter of the solid solution powder in this example measured by laser particle size analysis, 0.33 μm in terms of the oxygen content of the solid solution powder measured by a carbon-oxygen analyzer, and 0.1 wt% in terms of the carbon content of the solid solution powder_{1/ 4}Ta_1/4Ti_1/2)B₂The hafnium-based ternary solid solution boride ceramic has a grain size of 3.64 μm, a relative density of 96%, and a hardness of 31 GPa.

Prepared by the invention of (Hf)_aMe1_bMe2_c)B₂Hafnium-based ternary solid solution boride ceramic powder can be synthesized into single-phase solid solution powder in situ by a borothermic carbothermic reduction method; prepared (Hf)_aMe1_bMe2_c)B₂Hafnium-based ternary solid solution boride ceramic, which can be controlled by solid solution of different elements compared to single-phase boride ceramic or binary boride ceramic (Hf)_aMe1_bMe2_c)B₂The performance of the hafnium-based ternary solid solution boride ceramic. The grain size of the hafnium-based ternary solid solution boride ceramic is 2.45-6.62 mu m, and the relative density is 94-98%; the hardness of the hafnium-based ternary solid solution boride ceramic is 28-35 GPa.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations and simplifications are intended to be included in the scope of the present invention.

Claims (10)

1. A high hardness hafnium-based ternary solid solution boride ceramic, characterized in thatThe molecular formula is (Hf)_aMe1_bMe2_c)B₂Wherein a is more than or equal to 0.1 and less than or equal to 0.9 and 0<b<0.9，0<c<0.9, and a + b + c is 1; me1 and Me2 are Zr, Ta or Ti, and the ceramic is HfO₂Me oxide ZrO₂、Ta₂O₅、TiO₂Any two of them, B₄C. Adding carbon powder into a solvent, ball-milling and mixing to obtain mixed powder, pressing the mixed powder to obtain a blank, putting the blank into a graphite crucible, heating to 1400-1600 ℃, preserving heat, and carrying out vacuum heat treatment to obtain (Hf)_aMe1_bMe2_c)B₂Hafnium-based ternary solid solution boride powder; and (3) heating the ternary solid solution boride powder to 1000-1400 ℃ by adopting spark plasma sintering, filling the ternary solid solution boride powder into a protective atmosphere, heating to 1900-2100 ℃, and calcining under the pressure of 10-100 MP to obtain the ternary solid solution boride powder.

2. The high hardness hafnium based ternary solid solution boride ceramic of claim 1, wherein the (Hf) is_aMe1_bMe2_c)B₂The hafnium-based ternary solid solution boride powder has a purity of 95.0 to 99.9 wt% and a particle size of 0.1 to 1 μm.

3. The high hardness hafnium based ternary solid solution boride ceramic of claim 1, wherein the (Hf) is_aMe1_bMe2_c)B₂The hafnium-based ternary solid solution boride powder has an oxygen content of 0.01 to 5 wt% and a carbon content of 0.01 to 5 wt%.

4. The high hardness hafnium based ternary solid solution boride ceramic of claim 1, wherein the HfO₂、ZrO₂、Ta₂O₅And TiO₂The purity of the particles is 99.0-99.9 wt%, and the particle size is 0.1-10 μm; b is₄The purity of the C powder and the purity of the carbon powder are both 97-99.99 wt.%, and the particle size is 1-1.5 mu m.

5. The high-hardness hafnium-based ternary solid solution boride ceramic according to claim 1, wherein the hafnium-based ternary solid solution boride ceramic has a grain size of 2.45 to 6.62 μm and a relative density of 94 to 98%; the hardness of the hafnium-based ternary solid solution boride ceramic is 28-35 GPa.

6. The high hardness hafnium based ternary solid solution boride ceramic of claim 1, wherein the solvent is ethanol, propanol, methanol or acetone.

7. The high hardness hafnium based ternary solid solution boride ceramic of claim 1, wherein the protective atmosphere is N₂Or Ar.

8. The high-hardness hafnium-based ternary solid solution boride ceramic according to claim 1, wherein the temperature rise rate of the temperature rise to 1400 to 1600 ℃ is 5 to 15 ℃/min; the heat preservation time is 0.5-2 h; the heating rate is 100-400 ℃/min when the temperature is raised to 1000-1400 ℃; the heating rate is 100-400 ℃/min when the temperature is raised to 1900-2100 ℃.

9. The method for preparing the high-hardness hafnium-based ternary solid solution boride ceramic according to any one of claims 1 to 8, comprising the specific steps of:

s1, mixing HfO₂Me oxide ZrO₂、Ta₂O₅、TiO₂Any two of them, B₄C. Adding a solvent and a ball milling medium into carbon powder, mixing for 20-40 h on a ball mill, and drying to obtain mixed powder;

s2, placing the blank after the mixed powder is molded into a graphite crucible for vacuum heat treatment, heating to 1400-1600 ℃ at the speed of 5-15 ℃/min, and preserving heat for 0.5-2 h to obtain hafnium-based ternary solid solution boride powder;

s3, placing the hafnium-based ternary solid solution boride powder into a graphite mold, heating to 1000-1400 ℃ at the speed of 100-400 ℃/min by adopting discharge plasma sintering, filling protective atmosphere, heating to 1900-2100 ℃ at the speed of 100-400 ℃/min, preserving heat for 10-30 min, and pressurizing to 10-100 MPa for calcination to obtain the hafnium-based ternary solid solution boride powder ceramic.

10. The use of the high-hardness hafnium-based ternary solid solution boride ceramic according to any one of claims 1 to 8 in the field of production of superabrasive tool materials.

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