TiB2-based composite ceramic with high bending strength and preparation method thereof

Abstract

The application belongs to the field of non-oxide structural ceramics, and particularly relates to a TiB2-based composite ceramic with high bending strength and a preparation method thereof. TiN powder, B4C powder, Si powder, Al powder, B powder, BN powder, TiB2 powder, AlN powder and SiC powder are used as raw materials, the powder is proportioned, the raw material powder is mixed, rotary evaporated, dried and sieved, and then densification is realized by using a spark plasma sintering method to obtain the required TiB2-based composite ceramic. The raw material formula is optimized, the spark plasma sintering process is controlled, and the subsequent heat treatment-water quenching process is used, so that the bending strength of the TiB2 ceramic is significantly improved, and meanwhile, other excellent performances are ensured.

Description

Technical Field

[0001] This invention belongs to the field of non-oxide structured ceramics, specifically relating to a TiB2-based multiphase ceramic with high flexural strength and its preparation method. Background Technology

[0002] Titanium diboride (TiB2) ceramics have shown broad application prospects in aerospace, military equipment, nuclear industry, and high-temperature structural materials due to their high melting point, high hardness, high electrical conductivity, and good chemical stability. However, despite their many excellent physical and chemical properties, they are relatively brittle, have relatively low flexural strength at both room temperature and high temperature, and are prone to oxidation failure at high temperatures. This significantly limits their application range and reliability in practical engineering environments.

[0003] In recent years, extensive research has been conducted to improve the flexural strength of TiB2 ceramics, including introducing second-phase particles (such as SiC and Al2O3) to strengthen the matrix and optimizing the microstructure by controlling grain size and morphology. While these methods have improved the flexural strength of TiB2 ceramics to some extent, they still face challenges such as high cost, complex processes, and unstable results. Therefore, developing a new, more economical, efficient, and simpler method to significantly improve the flexural strength of TiB2 ceramics is of great significance for promoting the application of this material in a wider range of fields.

[0004] Existing TiB2 ceramics still suffer from the following problems: 1. Thermal stability: Due to changes in the coefficient of thermal expansion and high-temperature oxidation, the strength of TiB2 ceramics is affected after use in high-temperature environments, making the material prone to cracking or failure. 2. Microstructure control: The microstructure of TiB2 ceramics, such as grain size, impurity content, and phase distribution, directly affects its strength. Finding a way to optimize these parameters to improve strength is a challenge. 3. Interface problems: Interface defects may exist in TiB2 ceramics, such as grain boundary weakening and phase interface separation. These problems can significantly reduce the flexural strength of the material. 4. Heat treatment effects: The heat treatment process has a significant impact on the microstructure and properties of TiB2 ceramics. How to maintain or improve its strength during heat treatment is a problem that needs to be solved.

[0005] Based on the above problems, the present invention aims to effectively improve the flexural strength of TiB2 ceramics through innovative material design and processing technology, so as to meet the needs of modern engineering technology for high-performance ceramic materials. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a TiB2-based multiphase ceramic with high flexural strength and its preparation method. This invention significantly improves the flexural strength of TiB2 ceramics while maintaining other excellent properties through optimized raw material formulation, controlled spark plasma sintering (SPS) process, and subsequent heat treatment.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] This invention provides a TiB2-based multiphase ceramic with high flexural strength. The raw materials for the TiB2-based multiphase ceramic are selected from TiN powder, B4C powder, Si powder, Al powder, B powder, BN powder, TiB2 powder, AlN powder, and SiC powder. The raw materials are proportioned according to any one of the following chemical reaction equations (1) to (5):

[0009] 4TiN+3B4C+3Si=4TiB2+4BN+3SiC (1);

[0010] 4TiB2+4BN+3SiC=4TiB2+4BN+3SiC (2);

[0011] 3TiN+Al+8B+5.98BN=3TiB2+7.98BN+AlN (3);

[0012] 3TiB2+7.98BN+AlN=3TiB2+7.98BN+AlN (4);

[0013] 3TiN+Al+8B=3TiB2+2BN+AlN (5).

[0014] Preferably, the TiN powder has an average particle size of 0.5–10 μm and a purity >95%; the B4C powder has an average particle size of 1–10 μm and a purity >95%; the Si powder has an average particle size of 0.5–5 μm and a purity >95%; the Al powder has an average particle size of 0.1–10 μm and a purity >95%; the B powder has an average particle size of 0.2–10 μm and a purity ≥95%; the BN powder has an average particle size of 1–10 μm and a purity >95%; the TiB2 powder has an average particle size of 0.2–10 μm and a purity >95%; the AlN powder has an average particle size of 0.5–10 μm and a purity >95%; and the SiC powder has an average particle size of 0.2–10 μm and a purity >95%. Further, the SiC powder is α-SiC powder.

[0015] In the above scheme, the selection of raw material powder with fine particle size and high purity can help reduce the porosity during sintering, thereby improving the density and mechanical properties of the final product. Raw material ratio: According to the specific chemical reaction equations (1) to (5), the raw material ratio can ensure the formation of the required TiB2-based multiphase ceramic. At the same time, the introduced second phase (such as SiC, AlN, etc.) can effectively improve the microstructure of TiB2 and enhance its mechanical properties.

[0016] This invention also provides a method for preparing a TiB2-based multiphase ceramic with high flexural strength, comprising:

[0017] Step 1: Weigh the raw material powder according to the proportions of the designed chemical reaction equation, and after preliminary treatment, obtain the raw material powder required for sintering;

[0018] Step 2: Pour the raw material powder obtained in Step 1 into a mold and sinter it in a spark plasma sintering environment to obtain sintered multiphase ceramic.

[0019] Step 3: Heat-treat the multiphase ceramic obtained in Step 2, and after cooling, obtain the desired TiB2-based multiphase ceramic.

[0020] Preferably, in step 1, the preliminary treatment method of the raw material powder is as follows: the weighed raw material powder is added to a ball mill jar and mixed evenly, anhydrous ethanol and zirconium oxide balls are used as the ball milling media, the powder after rotary evaporation is dried in a vacuum drying oven, and then ground and sieved to obtain the raw material powder required for sintering.

[0021] Preferably, in step 2, the sintering temperature range is 1400℃~1800℃.

[0022] Preferably, in step 2, the sintering heating rate is 100-200℃ / min.

[0023] Preferably, in step 2, the sintering pressure is 30–60 MPa.

[0024] Preferably, in step 2, the sintering holding time is 5 to 20 minutes.

[0025] Preferably, in step 2, graphite paper is used to separate the inner wall of the mold from the raw material powder.

[0026] Preferably, in step 3, the heat treatment method is as follows: the heat treatment temperature is 800-1400℃, the heat treatment time is 10-120min, after the heat treatment is completed, the water is immediately immersed in 0-100℃ water for 10-120min, and finally the water is removed and allowed to cool naturally.

[0027] The above-described spark plasma sintering (SPS) process has the following sintering conditions: SPS sintering allows for rapid sintering at lower temperatures, avoiding grain growth caused by prolonged high temperatures, thus promoting the formation of a fine-grained structure and improving the material's flexural strength. Sintering pressure: Sintering at 30–60 MPa helps increase the material's density and reduce porosity, further enhancing its mechanical properties. Holding time: Shorter holding times (5–20 minutes) reduce the chance of grain growth, maintaining the fineness of the microstructure and improving the material's strength. Although the above preparation process can produce dense and uniformly refined TiB2-based multiphase ceramics, the material's strength still needs improvement.

[0028] The subsequent heat treatment and water quenching processes in the above scheme involve heat treatment at temperatures ranging from 800 to 1400°C in an air atmosphere. This heat treatment promotes the optimization of the internal microstructure of the material and forms a dense oxide layer on the material surface to close microcracks. The water quenching process involves rapid immersion in distilled water for cooling. The appearance of a compressive stress zone under the surface oxide layer is beneficial to significantly improving the strength of the material.

[0029] The technical solution provided by this invention has the following beneficial effects:

[0030] 1. By optimizing raw material formulations and innovating heat treatment processes, various TiB2-based multiphase ceramic systems were designed, providing a method to further improve the flexural strength of TiB2 ceramics. This is crucial for enhancing the material's performance in extreme environments. Examples 1-6 yielded dense TiB2-based multiphase ceramics with refined grains, uniform microstructure, and no impurities. Grain boundaries were tightly bonded without significant separation or weakening. After heat treatment and water quenching, the material maintained its integrity, with a relatively flat surface and no visible macroscopic cracks or obvious shape degradation. Compared to a single heat treatment process (Example 6), water quenching continuously healed microscopic defects on the surface and inside the material. The appearance of a compressive stress zone under the surface oxide layer helped suppress the initiation and propagation of cracks during transient water quenching before final failure, offsetting some thermal stress. Therefore, compared to the initial strength, the flexural strength increased continuously with the heat treatment temperature, with a maximum increase of over 50% at 1400℃ (Examples 1-5).

[0031] 2. Compared with other technologies, this invention employs a top-down strategy, enabling the sintering of ceramics with fine structures from coarse precursor powders. During the reaction process, particles can generate multiple nucleation sites, and the newly formed particles exhibit high sintering performance. Therefore, material densification can typically be achieved at temperatures lower than conventional hot-pressing sintering temperatures (at least 200°C lower). Furthermore, by optimizing the heat treatment temperature and time, oxidation and interfacial damage in TiB2 ceramics can be controlled, contributing to the refinement of the microstructure and effective defect control in TiB2-based composite phase ceramic materials.

[0032] 3. High-purity, inexpensive, and readily available raw material powders can be mixed and then processed using SPS to prepare TiB2-based multiphase ceramics with refined grains. The raw materials are readily available, and the preparation process, heat treatment, and water quenching are simple, with a short cycle time, and no sintering aids are required. It exhibits good repeatability and scalability, which is beneficial for the widespread application of TiB2 ceramics in industrial production. Attached Figure Description

[0033] Figure 1 The microstructure of the sample obtained by sintering in Example 1 is shown.

[0034] Figure 2 The microstructure of the sample from Example 1 after heat treatment at 1400℃;

[0035] Figure 3 The macroscopic morphology of the sample in Example 1 after heat treatment at 1400℃;

[0036] Figure 4 The microstructure of the sample obtained by sintering in Example 2 is shown.

[0037] Figure 5 The microstructure of the sample in Example 2 after heat treatment at 1000℃;

[0038] Figure 6 The macroscopic morphology of the sample in Example 2 after heat treatment at 1000℃;

[0039] Figure 7 The microstructure of the sample obtained by sintering in Example 3 is shown.

[0040] Figure 8 The microstructure of the sample in Example 3 after heat treatment at 1400℃;

[0041] Figure 9 The image shows the macroscopic morphology of the sample from Example 3 after heat treatment at 1400℃. Detailed Implementation

[0042] To enable those skilled in the art to better understand the technical solutions of the present invention, the preferred embodiments of the present invention are described below in conjunction with specific examples. However, these should not be construed as limiting the present invention and are merely examples.

[0043] Unless otherwise specified, the test methods or experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are obtained from conventional commercial sources or prepared by conventional methods.

[0044] Example 1

[0045] TiN powder, B4C powder and Si powder were used as raw materials and were mixed according to equation (1).

[0046] The phase composition (volume content) of the obtained sample was 43% TiB2-26% SiC-31% BN.

[0047] Using anhydrous ethanol and zirconia balls as the ball milling media, TiN, B4C, and Si powders were uniformly mixed according to stoichiometric ratios. The mixture was then subjected to rotary evaporation, drying, grinding, and sieving, before being poured into a graphite mold. A 0.2 mm thick layer of graphite paper separated the inner wall of the mold sleeve from the powder. The temperature was raised to 400 °C, and a pressure of 40 MPa was applied to the sample. The sample was then heated to 1700 °C at a rate of 100 °C / min and maintained at 1700 °C and 40 MPa for 5 min. Finally, the pressure was reduced to 3 MPa and heating was stopped, allowing the sample to cool to room temperature in the furnace. The obtained ceramic had a relative density of 98.1% and an initial flexural strength of 521 MPa at room temperature. Several finely processed samples (size: 2 × 2.5 × 25 mm) were then tested. 3 The samples were placed in heating furnaces at 800℃, 1000℃, 1200℃, and 1400℃ respectively and held for 10 minutes. After the holding time, the samples were immediately immersed in distilled water at 100℃ for 10 minutes. Finally, they were removed from the water and allowed to cool naturally in a well-ventilated area for 30 minutes. The final strengths of the materials after heat treatment and water quenching at 800℃, 1000℃, 1200℃, and 1400℃ were 597MPa, 647MPa, 681MPa, and 733MPa, respectively, with a maximum increase of 40.6% (Table 1).

[0048] Figure 1 The image shows the microstructure of the sample obtained by sintering in Example 1. Figure 2 The image shows the microstructure of the sample from Example 1 after heat treatment at 1400℃. Figure 3 The macroscopic morphology of the sample in Example 1 after heat treatment at 1400℃ is shown below. Figures 1-3It can be seen that the dense and homogeneous TiB2-SiC-BN multiphase ceramic obtained by sintering at 1700℃ has significantly refined grains; the sample maintains its integrity after heat treatment at 1400℃, without visible macroscopic cracks or obvious shape degradation; the surface is covered by a dense oxide film, exhibiting an island-like morphology of TiO2 particle aggregation, and the surface microcracks are repaired; the internal ceramic matrix is ​​subjected to compressive stress from the surface oxide layer, and its strength is significantly improved.

[0049] Example 2

[0050] TiB2 powder, BN powder and SiC powder were used as raw materials and were mixed according to equation (2).

[0051] The phase composition (volume content) of the obtained sample was 43% TiB2-26% SiC-31% BN.

[0052] Using anhydrous ethanol and zirconia balls as the ball milling media, TiB2, BN, and SiC powders were uniformly mixed according to stoichiometric ratios. The mixture was then subjected to rotary evaporation, drying, grinding, and sieving, before being poured into a graphite mold. A 0.2 mm thick layer of graphite paper separated the inner wall of the mold sleeve from the powder. The temperature was raised to 400℃, and a pressure of 60 MPa was applied to the sample. The sample was then heated to 1800℃ at a rate of 100℃ / min and maintained at 1800℃ and 60 MPa for 20 min. Finally, the pressure was reduced to 3 MPa and heating was stopped, allowing the sample to cool to room temperature in the furnace. The obtained ceramic had a relative density of 98.5% and an initial flexural strength of 457 MPa at room temperature. Several finely processed samples (size: 2 × 2.5 × 25 mm) were then tested. 3 The samples were placed in heating furnaces at 800℃, 1000℃, 1200℃, and 1400℃ for 15 minutes each. After heating, the samples were immediately immersed in distilled water at 100℃ for 20 minutes. Finally, they were removed from the water and allowed to cool naturally in a well-ventilated area for 30 minutes. The final strengths of the materials after heat treatment and water quenching at 800℃, 1000℃, 1200℃, and 1400℃ were 502 MPa, 541 MPa, 602 MPa, and 659 MPa, respectively, with a maximum increase of 44.2% (Table 1).

[0053] Figure 4 The image shows the microstructure of the sample obtained by sintering in Example 2. Figure 5 The image shows the microstructure of the sample from Example 2 after heat treatment at 1000℃. Figure 6 The macroscopic morphology of the sample in Example 2 after heat treatment at 1000℃ is shown below. Figures 4-6It can be seen that the dense and homogeneous TiB2-SiC-BN multiphase ceramic obtained by sintering at 1800℃ has no visible pores; after heat treatment at 1000℃, the sample still maintains its integrity, with a relatively flat surface and no obvious shape degradation; the surface is covered with a continuous oxide layer, which is beneficial to reduce the sensitivity to microcracks and repair microcracks.

[0054] Example 3

[0055] TiN powder, Al powder, B powder and BN powder are used as raw materials and are prepared according to equation (3).

[0056] The phase composition (volume content) of the obtained sample was 32% TiB2-8% AlN-60% BN.

[0057] Using anhydrous ethanol and zirconia balls as the ball milling media, four powders—TiN, Al, B, and BN—were uniformly mixed according to stoichiometric ratios. The mixture was then subjected to rotary evaporation, drying, grinding, and sieving, before being poured into a graphite mold. A 0.2 mm thick layer of graphite paper separated the inner wall of the mold sleeve from the powder. The temperature was raised to 400 °C, and a pressure of 60 MPa was applied to the sample. The sample was then heated to 1800 °C at a rate of 100 °C / min and maintained at 1800 °C and 60 MPa for 20 min. Finally, the pressure was reduced to 3 MPa and heating was stopped, allowing the sample to cool to room temperature in the furnace. The obtained ceramic had a relative density of 98.2% and an initial flexural strength of 324 MPa at room temperature. Several finely processed samples (size: 2 × 2.5 × 25 mm) were then tested. 3 The samples were placed in heating furnaces at 800℃, 1000℃, 1200℃, and 1400℃ for 15 minutes each. After heating, the samples were immediately immersed in distilled water at 100℃ for 20 minutes. Finally, they were removed from the water and allowed to cool naturally in a well-ventilated area for 30 minutes. The final strengths of the materials after heat treatment and water quenching at 800℃, 1000℃, 1200℃, and 1400℃ were 380MPa, 421MPa, 436MPa, and 484MPa, respectively, with a maximum increase of 49.4% (Table 1).

[0058] Figure 7 The image shows the microstructure of the sample obtained by sintering in Example 3. Figure 7 The image shows the microstructure of the sample from Example 3 after heat treatment at 1400℃. Figure 7 The macroscopic morphology of the sample in Example 3 after heat treatment at 1400℃ is shown below. Figures 7-9 It can be seen that sintering at 1800℃ can yield dense TiB2-AlN-BN multiphase ceramics; after heat treatment at 1400℃, the sample still maintains its integrity and does not show obvious shape degradation; the surface is covered with dense and continuous needle-like oxide particles, which is beneficial for closing microcracks.

[0059] Example 4

[0060] TiB2 powder, AlN powder and BN powder were used as raw materials and were mixed according to equation (4).

[0061] The phase composition (volume content) of the obtained sample was 32% TiB2-8% AlN-60% BN.

[0062] Using anhydrous ethanol and zirconia balls as the ball milling media, TiB2, AlN, and BN powders were uniformly mixed according to stoichiometric ratios. The mixture was then subjected to rotary evaporation, drying, grinding, and sieving, before being poured into a graphite mold. A 0.2 mm thick layer of graphite paper separated the inner wall of the mold sleeve from the powder. The temperature was raised to 400℃, and a pressure of 60 MPa was applied to the sample. The sample was then heated to 1800℃ at a rate of 100℃ / min and maintained at 1800℃ and 60 MPa for 20 min. Finally, the pressure was reduced to 3 MPa and heating was stopped, allowing the sample to cool to room temperature in the furnace. The obtained ceramic had a relative density of 98.4% and an initial flexural strength of 252 MPa at room temperature. Several finely processed samples (size: 2 × 2.5 × 25 mm) were then tested. 3 The samples were placed in furnaces at 800℃, 1000℃, 1200℃, and 1400℃ for 15 minutes each. After the heating was completed, the samples were immediately immersed in distilled water at 100℃ for 10 minutes. Finally, they were removed from the water and allowed to cool naturally in a well-ventilated area for 30 minutes. The final strengths of the materials after heat treatment and water quenching at 800℃, 1000℃, 1200℃, and 1400℃ were 302 MPa, 331 MPa, 364 MPa, and 382 MPa, respectively, with a maximum increase of 51.6% (Table 1).

[0063] Example 5

[0064] TiN powder, Al powder and B powder are used as raw materials and are prepared according to equation (5).

[0065] The phase composition (volume content) of the obtained sample was 56% TiB2-17% AlN-27% BN.

[0066] Using anhydrous ethanol and zirconia balls as the ball milling media, TiN, Al, and B powders were uniformly mixed according to stoichiometric ratios. The mixture was then subjected to rotary evaporation, drying, grinding, and sieving, before being poured into a graphite mold. A 0.2 mm thick layer of graphite paper separated the inner wall of the mold sleeve from the powder. The temperature was raised to 400 °C, and a pressure of 40 MPa was applied to the sample. The sample was then heated to 1800 °C at a rate of 100 °C / min and maintained at 1800 °C and 40 MPa for 20 min. Finally, the pressure was reduced to 3 MPa and heating was stopped, allowing the sample to cool to room temperature in the furnace. The obtained ceramic had a relative density of 98.4% and an initial flexural strength of 412 MPa at room temperature. Several finely processed samples (size: 2 × 2.5 × 25 mm) were then tested. 3 The samples were placed in heating furnaces at 800℃, 1000℃, 1200℃, and 1400℃ for 15 minutes each. After heating, the samples were immediately immersed in distilled water at 80℃ for 15 minutes. Finally, they were removed from the water and allowed to cool naturally in a well-ventilated area for 30 minutes. The final strengths of the materials after heat treatment and water quenching at 800℃, 1000℃, 1200℃, and 1400℃ were 495MPa, 515MPa, 530MPa, and 594MPa, respectively, with a maximum increase of 44.2% (Table 1).

[0067] Example 6

[0068] TiN powder, B4C powder and Si powder were used as raw materials and were mixed according to equation (1).

[0069] The phase composition (volume content) of the obtained sample was 43% TiB2-26% SiC-31% BN.

[0070] Using anhydrous ethanol and zirconia balls as the ball milling media, TiN, B4C, and Si powders were uniformly mixed according to stoichiometric ratios. The mixture was then subjected to rotary evaporation, drying, grinding, and sieving, before being poured into a graphite mold. A 0.2 mm thick layer of graphite paper separated the inner wall of the mold sleeve from the powder. The temperature was raised to 400 °C, and a pressure of 60 MPa was applied to the sample. The sample was then heated to 1800 °C at a rate of 100 °C / min and held at 1800 °C and 60 MPa for 5 min. Finally, the pressure was reduced to 3 MPa and heating was stopped, allowing the sample to cool to room temperature in the furnace. The obtained ceramic had a relative density of 98.9% and an initial flexural strength of 543 MPa at room temperature. Several finely processed samples (size: 2 × 2.5 × 25 mm) were then tested. 3The samples were placed in heating furnaces at 800℃, 1000℃, 1200℃, and 1400℃ respectively and held for 10 minutes. After the holding time, the samples were removed directly and placed in a well-ventilated area to cool naturally for 30 minutes. The final strengths of the materials after heat treatment at 800℃, 1000℃, 1200℃, and 1400℃ were 503 MPa, 485 MPa, 425 MPa, and 302 MPa, respectively, with a maximum reduction of 44.4% (Table 1).

[0071] The TiB2-based multiphase ceramics prepared according to the above embodiments showed no obvious cracks or shape degradation on the surface of the samples after heat treatment at different temperatures. The bending strength is shown in Table 1 below.

[0072] Table 1

[0073]

[0074]

[0075] As shown in Table 1 above, a single heat treatment process will cause the bending strength of the material to decrease continuously with temperature (Example 6), while heat treatment combined with water quenching (Examples 1-5) will continuously increase the strength of the material with heat treatment temperature, with a maximum increase of more than 50% at 1400℃.

[0076] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A TiB2-based multiphase ceramic with high flexural strength, characterized in that, The raw materials for the TiB2-based multiphase ceramic are selected from TiN powder, B4C powder, Si powder, Al powder, B powder, BN powder, TiB2 powder, AlN powder, and SiC powder. The raw materials are proportioned according to any one of the following chemical reaction equations (1) to (5): 4TiN+3B4C+3Si=4TiB2+4BN+3SiC (1); 4TiB2+4BN+3SiC=4TiB2+4BN+3SiC (2); 3TiN+Al+8B+5.98BN=3TiB2+7.98BN+AlN (3); 3TiB2+7.98BN+AlN=3TiB2+7.98BN+AlN (4); 3TiN+Al+8B=3TiB2+2BN+AlN (5); The preparation method of the TiB2-based multiphase ceramic includes: Step 1: Weigh the raw material powder according to the proportions of the designed chemical reaction equation, and after preliminary treatment, obtain the raw material powder required for sintering; Step 2: Pour the raw material powder obtained in Step 1 into a mold and sinter it in a spark plasma sintering environment to obtain sintered multiphase ceramic. Step 3: Heat-treat the multiphase ceramic obtained in Step 2 at a temperature of 800~1400°C for 10-120 min. After heat treatment, immediately immerse it in water at 20-100°C for 10-120 min. Finally, remove it from the water and allow it to cool naturally. After cooling, the desired TiB2-based multiphase ceramic is obtained.

2. The high flexural strength TiB2-based multiphase ceramic according to claim 1, characterized in that, The TiN powder has an average particle size of 0.5~10 μm and a purity >95%; the B4C powder has an average particle size of 1~10 μm and a purity >95%; the Si powder has an average particle size of 0.5~5 μm and a purity >95%; the Al powder has an average particle size of 0.1~10 μm and a purity >95%; the B powder has an average particle size of 0.2~10 μm and a purity ≥95%; the BN powder has an average particle size of 1~10 μm and a purity >95%; the TiB2 powder has an average particle size of 0.2~10 μm and a purity >95%; the AlN powder has an average particle size of 0.5~10 μm and a purity >95%; and the SiC powder has an average particle size of 0.2~10 μm and a purity >95%.

3. The high flexural strength TiB2-based multiphase ceramic according to claim 1, characterized in that, In step 1, the preliminary treatment method of the raw material powder is as follows: the weighed raw material powder is added to a ball mill jar and mixed evenly, anhydrous ethanol and zirconium oxide balls are used as the ball milling media, the powder after rotary evaporation is dried in a vacuum drying oven, and then ground and sieved to obtain the raw material powder required for sintering.

4. The high flexural strength TiB2-based multiphase ceramic according to claim 1, characterized in that, In step 2, the sintering temperature range is 1400°C to 1800°C.

5. The high flexural strength TiB2-based multiphase ceramic according to claim 1, characterized in that, In step 2, the sintering heating rate is 100-200°C / min.

6. The high flexural strength TiB2-based multiphase ceramic according to claim 1, characterized in that, In step 2, the sintering pressure is 30~60 MPa.

7. The high flexural strength TiB2-based multiphase ceramic according to claim 1, characterized in that, In step 2, the sintering holding time is 5~20 min.

8. The high flexural strength TiB2-based multiphase ceramic according to claim 1, characterized in that, In step 2, graphite paper is used to separate the inner wall of the mold from the raw material powder.

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