Preparation method of boron carbide ceramic, boron carbide ceramic and application of boron carbide ceramic

Abstract

The invention provides a preparation method of boron carbide ceramic, the boron carbide ceramic and application of the boron carbide ceramic, and belongs to the technical field of boron carbide ceramics.The preparation method comprises the steps that S1, by mass, 76.5%-81.5% of boron carbide, 16%-20% of titanium carbide and 2.5%-3.5% of nickel-yttrium oxide composite balls are mixed and dried, and mixed powder is obtained; s2, adding a binder into the mixed powder obtained in the step S1, granulating, and pressing under the pressure of 330-350 MPa to form a mold, so as to obtain a pressing mold; and S3, putting the pressing die obtained in the step S2 into a carbon tube furnace, carrying out hot pressed sintering for 1-1.2 hours at 2150-2200 DEG C under the load of 25-35 MPa under the protection of inert gas, and cooling to room temperature along with the furnace, so as to obtain the boron carbide ceramic. The sintering density of the prepared boron carbide ceramic can be effectively improved, and meanwhile the bending strength of the boron carbide ceramic is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of boron carbide ceramics, and in particular relates to a preparation method of boron carbide ceramics, boron carbide ceramics and applications thereof. Background Art

[0002] Boron carbide composite ceramic materials possess numerous excellent physical, chemical, and mechanical properties and are widely used in a variety of fields, such as petrochemicals, machining, electronic materials, and LED lighting. In the petrochemical sector, especially in chemical machinery seals, the operating environment places stringent requirements on material performance.

[0003] Chemical machinery seals are exposed to strong acids, strong bases, high temperatures, and dynamic mechanical loads for extended periods of time. They must meet both chemical stability and mechanical reliability requirements, requiring boron carbide composite ceramic materials to possess both high density and high flexural strength. This high-density structure reduces open pores and grain boundary channels, preventing corrosive media (such as concentrated sulfuric acid and molten salts) from penetrating the material and causing chemical erosion or intergranular corrosion, thereby extending seal life. High flexural strength ensures structural integrity under alternating stresses such as frequent starts and stops, vibration, and medium pressure fluctuations, thereby extending seal life.

[0004] In the prior art, the titanium boride generated during the reaction sintering process of boron carbide and titanium carbide is distributed on the boron carbide phase boundary, and no new interface phase is formed. At the same time, carbon (a thin layer) will appear. The titanium boride and carbon formed in situ can both promote the sintering of boron carbide and increase the sintering density of the composite ceramic material. However, a small amount of carbon is beneficial to improving the flexural strength of the composite ceramic material. As the proportion of titanium carbide increases, more carbon will be produced, which will in turn reduce the flexural strength of the composite ceramic material. Summary of the Invention

[0005] To solve the problems existing in the background technology, the present invention provides a preparation method of boron carbide ceramics, boron carbide ceramics and applications thereof, which ensure that the sintering density of the boron carbide ceramics is effectively improved while improving their flexural strength.

[0006] In order to achieve the above objectives, in a first aspect, the present invention provides a method for preparing boron carbide ceramics, comprising the following steps:

[0007] S1. Mixing, by mass percentage, 76.5%-81.5% of boron carbide, 16%-20% of titanium carbide, and 2.5%-3.5% of nickel-yttrium oxide composite balls, and drying to obtain a mixed powder;

[0008] S2. Add a binder to the mixed powder obtained in S1, granulate, and press into a mold at a pressure of 330-350 MPa to obtain a mold;

[0009] S3. Place the die obtained in S2 in a carbon tube furnace, and hot press sinter under inert gas protection at 2150-2200° C. and a load of 25-35 MPa for 1-1.2 hours, and then cool to room temperature in the furnace to obtain the boron carbide ceramic.

[0010] Furthermore, the preparation method of the nickel-yttrium oxide composite ball is as follows: nano nickel powder and nano yttrium oxide are mixed in a mass ratio of (1-1.2):1, added into a ball mill, wet ball milled, filtered, dried, ground, and sieved to obtain the nickel-yttrium oxide composite ball.

[0011] Furthermore, in the wet ball milling treatment, ethanol medium is used, the ball-to-material ratio is (4-5):1, the rotation speed is 220-270 rpm, and the ball milling time is 3.5-4 hours.

[0012] Furthermore, the particle size of the nickel-yttrium oxide composite ball is 1-3 μm.

[0013] Furthermore, the particle size of the boron carbide is 3-5 μm, and the particle size of the titanium carbide is 1-3 μm.

[0014] Furthermore, in S2, the binder is a polyvinyl alcohol aqueous solution with a mass concentration of 3.5%-4.5%; the mass of the binder is 6%-8% of the mass of the mixed powder.

[0015] Furthermore, in S1, the specific operation of drying is: placing the mixed powder in a vacuum drying oven and drying at 95-100° C. for 30-36 hours.

[0016] In a second aspect, the present invention provides a boron carbide ceramic prepared by the above-mentioned preparation method.

[0017] In a third aspect, the present invention provides an application of a boron carbide ceramic, wherein the boron carbide ceramic is prepared by the above-mentioned preparation method, and the boron carbide ceramic is used for a sealing ring of a chemical machinery.

[0018] This application has the following beneficial effects:

[0019] The present invention introduces nickel-yttrium oxide composite balls into a boron carbide and titanium carbide sintering system. On the one hand, the yttrium oxide and nickel work synergistically to react with the carbon sintering to form a gradient interface layer, which better controls (reduces) the thickness of the carbon layer, preventing the carbon layer thickness from exceeding a critical value and causing a significant reduction in the direct contact area of the boron carbide particles. This ensures that the carbon layer has a moderate thickness as an interface transition phase, improves the interface bonding strength by filling the gaps between the boron carbide particles, and thus synergistically improves the flexural strength of the resulting boron carbide ceramic.

[0020] On the other hand, rare earth elements reduce the diffusion activation energy of carbon atoms, promote uniform film formation rather than agglomeration, and thus reduce the proportion of carbon atoms forming flaky or network structures; at the same time, nickel catalyzes the preferential growth of carbon atoms along the crystal plane, effectively avoiding the flaky or network structure of carbon atoms, thereby further reducing the proportion of carbon atoms forming flaky or network structures; avoiding cracks from preferentially extending along the carbon layer interface (reduced energy dissipation), ensuring that cracks tend to extend through the crystal along the boron carbide grains (high energy dissipation), thereby superimposing and improving the bending strength of the obtained boron carbide ceramics.

[0021] Nickel-yttrium oxide composite balls are prepared using an ethanol-based wet milling process. Liquid phase interface manipulation creates a physical contact interface between nickel and yttrium oxide at the subnanometer to multinanometer scale, achieving precise matching of the spacing between the two, effectively enhancing a synergistic effect. Furthermore, this composite structure induces in-situ generated nanoscale carbon to selectively fill grain boundary defects, promoting the directional growth of a three-dimensional interconnected network within the sintering neck, thereby simultaneously improving sintering density. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 , a comparison trend diagram of density data of boron carbide ceramics obtained from Examples 1 to 4 and Comparative Examples 1 to 4 in the test examples of the present invention;

[0023] Figure 2 , a comparative trend diagram of the flexural strength data of the boron carbide ceramics obtained in Examples 1 to 4 and Comparative Examples 1 to 4 in the test examples of the present invention. DETAILED DESCRIPTION

[0024] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present application are all commercially available.

[0026] Example 1

[0027] A method for preparing boron carbide ceramics comprises the following steps:

[0028] S1. Mix 79% boron carbide, 18% titanium carbide, and 3% nickel-yttrium oxide composite balls by mass (stirring at 150 rpm for 20 min), place in a vacuum drying oven, and dry at about 98° C. for 32 h to obtain a mixed powder.

[0029] The particle size of boron carbide is 3-5 μm and was purchased from Zhengzhou Haixu Abrasive Co., Ltd. The particle size of titanium carbide is 1-3 μm and was purchased from Qinghe County Benyu Metal Materials Co., Ltd.

[0030] The nickel-yttrium oxide composite balls were prepared as follows: nano-nickel powder and nano-yttrium oxide were mixed in a 1:1 mass ratio and added to a ball mill using ethanol at a ball-to-material ratio of 5:1 at a rotational speed of 240 rpm. After 4 hours of ball milling, the mixture was filtered, dried, ground, and sieved to obtain nickel-yttrium oxide composite balls with a particle size of 1-3 μm. Nano-nickel powder (50% average particle size, 100 nm) was purchased from Shanghai Pantian Powder Materials Co., Ltd. Nano-yttrium oxide (50% average particle size, 80 nm) was purchased from Shandong Xinbaiyi Metal Materials Co., Ltd.

[0031] S2. Add a binder to the mixed powder. The binder is a 4% aqueous solution of polyvinyl alcohol; the mass of the binder is 7% of the mass of the mixed powder. Granulation is performed as follows: the mixed powder and binder are mixed at a low speed (30 rpm, 15 minutes) in a kneader to form a wet material. The wet material is granulated in a screw extruder granulator (pore size 1.2 mm). The granules are dried in a fluidized bed at 40°C to a moisture content of approximately 3%, and sieved (80 mesh). The granules are then poured into a mold (cavity size Φ50 mm × 10 mm), pressed at 340 MPa for 6 minutes, and then released to obtain a compression mold.

[0032] S3. Place the die in a carbon tube furnace, and hot press sinter the die at 2200° C. and 30 MPa under hydrogen protection for 1.2 hours, and then cool the die to room temperature to obtain boron carbide ceramics.

[0033] Example 2

[0034] The difference between this embodiment and embodiment 1 is that: a method for preparing boron carbide ceramics comprises the following steps:

[0035] S1. Mix 77% boron carbide, 20% titanium carbide and 3% nickel-yttrium oxide composite balls by mass, place in a vacuum drying oven, and dry at about 98° C. for 32 hours to obtain a mixed powder.

[0036] S2. Add a binder to the mixed powder, granulate, and press into a mold at a pressure of 330 MPa to obtain a mold. The binder is a polyvinyl alcohol aqueous solution with a mass concentration of 3.5%; the mass of the binder is 8% of the mass of the mixed powder.

[0037] S3. Place the die in a carbon tube furnace, and hot press and sinter the die under an inert gas protection at 2200° C. and a load of 35 MPa for 1 hour, and then cool the die to room temperature to obtain boron carbide ceramics.

[0038] Example 3

[0039] The difference between this embodiment and embodiment 1 is that: a method for preparing boron carbide ceramics comprises the following steps:

[0040] S1. Mix 81% boron carbide, 16% titanium carbide, and 3% nickel-yttrium oxide composite balls by mass, place in a vacuum drying oven, and dry at 100° C. for 30 hours to obtain a mixed powder.

[0041] S2. Add a binder to the mixed powder, granulate, and press into a mold at a pressure of 350 MPa to obtain a mold. The binder is a polyvinyl alcohol aqueous solution with a mass concentration of 4.5%; the mass of the binder is 6% of the mass of the mixed powder.

[0042] S3. Place the die in a carbon tube furnace, and hot press sinter the die at 2150° C. and 35 MPa under inert gas protection for 1.2 hours, and then cool the die to room temperature to obtain boron carbide ceramics.

[0043] Example 4

[0044] The difference between this embodiment and embodiment 1 is that: a method for preparing boron carbide ceramics comprises the following steps:

[0045] S1. 76.5% boron carbide, 20% titanium carbide and 3.5% nickel-yttrium oxide composite balls were mixed by mass, placed in a vacuum drying oven, and dried at 100° C. for 30 h to obtain a mixed powder.

[0046] S2. Add a binder to the mixed powder, granulate, and press into a mold at a pressure of 340 MPa to obtain a mold. The binder is a polyvinyl alcohol aqueous solution with a mass concentration of 4.5%; the mass of the binder is 7% of the mass of the mixed powder.

[0047] S3. Place the die in a carbon tube furnace, and hot press sinter the die under inert gas protection at 2200° C. and a load of 30 MPa for 1.2 hours, and then cool the die to room temperature to obtain boron carbide ceramics.

[0048] Comparative Example 1

[0049] The difference between this comparative example and Example 1 is that the raw materials are 90% boron carbide and 10% titanium carbide.

[0050] Specifically as follows: A method for preparing boron carbide ceramics comprises the following steps:

[0051] S1. Mix 90% boron carbide and 10% titanium carbide by mass, place in a vacuum drying oven, and dry at about 98° C. for 32 hours to obtain a mixed powder.

[0052] S2. Add a binder to the mixed powder, granulate, and press into a mold at a pressure of 340 MPa to obtain a mold. The binder is a polyvinyl alcohol aqueous solution with a mass concentration of 4%; the mass of the binder is 7% of the mass of the mixed powder.

[0053] S3. Place the die in a carbon tube furnace, and hot press sinter the die at 2200° C. and 30 MPa under hydrogen protection for 1.2 hours, and then cool the die to room temperature to obtain boron carbide ceramics.

[0054] Comparative Example 2

[0055] The difference between this comparative example and Example 1 is that the raw materials are 82% boron carbide and 18% titanium carbide.

[0056] Specifically as follows: A method for preparing boron carbide ceramics comprises the following steps:

[0057] S1. Mix 82% boron carbide and 18% titanium carbide by mass, place in a vacuum drying oven, and dry at about 98° C. for 32 hours to obtain a mixed powder.

[0058] S2. Add a binder to the mixed powder, granulate, and press into a mold at a pressure of 340 MPa to obtain a mold. The binder is a polyvinyl alcohol aqueous solution with a mass concentration of 4%; the mass of the binder is 7% of the mass of the mixed powder.

[0059] S3. Place the die in a carbon tube furnace, and hot press sinter the die at 2200° C. and 30 MPa under hydrogen protection for 1.2 hours, and then cool the die to room temperature to obtain boron carbide ceramics.

[0060] Comparative Example 3

[0061] The difference between this comparative example and Example 1 is that the raw materials are 87% boron carbide, 10% titanium carbide and 3% nickel-yttrium oxide composite balls.

[0062] Specifically as follows: A method for preparing boron carbide ceramics comprises the following steps:

[0063] S1. Mix 87% boron carbide, 10% titanium carbide and 3% nickel-yttrium oxide composite balls by mass, place in a vacuum drying oven, and dry at about 98° C. for 32 hours to obtain a mixed powder.

[0064] S2. Add a binder to the mixed powder, granulate, and press into a mold at a pressure of 340 MPa to obtain a mold. The binder is a polyvinyl alcohol aqueous solution with a mass concentration of 4%; the mass of the binder is 7% of the mass of the mixed powder.

[0065] S3. Place the die in a carbon tube furnace, and hot press sinter the die at 2200° C. and 30 MPa under hydrogen protection for 1.2 hours, and then cool the die to room temperature to obtain boron carbide ceramics.

[0066] Comparative Example 4

[0067] The difference between this comparative example and Example 1 is that the raw materials are 79% boron carbide, 18% titanium carbide, 1.5% nano nickel powder and 1.5% nano yttrium oxide.

[0068] Specifically as follows: A method for preparing boron carbide ceramics comprises the following steps:

[0069] S1. Mix 79% boron carbide, 18% titanium carbide, 1.5% nano nickel powder and 1.5% nano yttrium oxide by mass, place in a vacuum drying oven, and dry at about 98° C. for 32 hours to obtain a mixed powder.

[0070] S2. Add a binder to the mixed powder, granulate, and press into a mold at a pressure of 340 MPa to obtain a mold. The binder is a polyvinyl alcohol aqueous solution with a mass concentration of 4%; the mass of the binder is 7% of the mass of the mixed powder.

[0071] S3. Place the die in a carbon tube furnace, and hot press sinter the die at 2200° C. and 30 MPa under hydrogen protection for 1.2 hours, and then cool the die to room temperature to obtain boron carbide ceramics.

[0072] Test example

[0073] Test Subjects: Boron carbide ceramics were produced using Examples 1-4 and Comparative Examples 1-4. Test Items: ① Sintered density; actual density was determined using the displacement method; sintered density = (actual density / theoretical density) × 100%. ② Flexural strength; tested in accordance with GB / T6569-2006. Test Results: See Table 1.

[0074] Table 1. Test example data

[0075] Sintered density (%) Flexural strength (MPa) Example 1 95.2 637.8 Example 2 95.6 635.4 Example 3 95.1 634.9 Example 4 95.5 637.1 Comparative Example 1 88.7 615.4 Comparative Example 2 91.6 598.2 Comparative Example 3 91.8 625.2 Comparative Example 4 94.9 628.7

[0076] Result analysis: Combining the data in Table 1 and Figure 1-Figure 2 , by analyzing Examples 1 to 4, it can be seen that the sintered density of the boron carbide ceramics prepared in the present invention (Examples 1 to 4) is as high as 95.1% or more, and the flexural strength is as high as 634.0 MPa or more.

[0077] Combining the data in Table 1 and Figure 1-Figure 2, Example 1 and Comparative Examples 1 to Comparative Examples 4 were analyzed, and specifically by comparing Comparative Example 1 with Comparative Example 2, it can be seen that when the raw material components are only boron carbide and titanium carbide, the mass proportion of titanium carbide is increased from 10% (Comparative Example 1) to 18% (Comparative Example 2). As a result, the density of the boron carbide ceramic is improved, but the flexural strength is significantly reduced.

[0078] This is because, in terms of density, the titanium boride generated during the reaction sintering of boron carbide and titanium carbide is distributed on the boron carbide phase boundary, and no new interface phase is formed. At the same time, a thin carbon layer will appear. When the titanium carbide content is moderate (the titanium carbide content of 18% does not exceed the corresponding threshold in this aspect), the titanium boride and carbon formed in situ can promote the sintering of boron carbide and continuously improve the sintering density of the composite ceramic.

[0079] In terms of flexural strength, when the titanium carbide content is moderate (titanium carbide content ≤ the corresponding threshold in this regard), the thickness of the generated carbon layer is small, which can serve as an interface transition phase, improving the interface bonding strength by filling the gaps between the boron carbide particles; and at this time, the carbon layer morphology is mainly nano-film-like, and cracks tend to extend through the boron carbide grains (high energy dissipation). When the titanium carbide content is too high (a titanium carbide content of 18% has exceeded the corresponding threshold in this regard), the carbon layer thickness is too large, resulting in a significant reduction in the direct contact area of the boron carbide particles, leading to a decrease in interface bonding strength; and at this time, the carbon layer morphology is mainly flaky or mesh-like, and cracks preferentially extend along the carbon layer interface (reduced energy dissipation), and the flexural strength decreases instead.

[0080] Specifically, by comparing Comparative Example 1 and Comparative Example 3, it can be seen that when the mass of titanium carbide accounts for 10% (Comparative Example 1), 3% nickel-yttrium oxide composite balls are added to the raw material components (Comparative Example 3), and the density and flexural strength of the boron carbide ceramic obtained as a result are increased. Combining Comparative Example 2 with Example 1, it can be seen that when the mass of titanium carbide accounts for 18% (Comparative Example 2), 3% nickel-yttrium oxide composite balls are added to the raw material components (Example 1), and the density and flexural strength of the boron carbide ceramic obtained as a result are also increased. Among them, the flexural strength improvement of the boron carbide ceramic obtained in Example 1 compared to Comparative Example 2 is significantly greater than the flexural strength improvement of the boron carbide ceramic obtained in Example 3 compared to Comparative Example 1; so that the flexural strength of the boron carbide ceramic finally obtained in Example 1 is greater than the flexural strength of the boron carbide ceramic finally obtained in Example 3.

[0081] This is because, on the one hand, yttrium oxide and nickel work synergistically, reacting with carbon sintering to form a gradient interface layer, which can better control (reduce) the thickness of the carbon layer, avoid the carbon layer thickness exceeding the critical value and causing a significant reduction in the direct contact area of the boron carbide particles, and ensure that the carbon layer of moderate thickness can serve as an interface transition phase, thereby improving the interface bonding strength by filling the gaps between the boron carbide particles, and thus synergistically improving the flexural strength of the boron carbide ceramics. On the other hand, rare earth elements can reduce the diffusion activation energy of carbon atoms, promote uniform film formation rather than agglomeration, thereby reducing the proportion of carbon atoms forming flaky or network structures; at the same time, nickel can catalyze the preferential growth of carbon atoms along the crystal plane, effectively avoiding the flaky or network structure of carbon atoms, thereby further reducing the proportion of carbon atoms forming flaky or network structures; effectively avoiding cracks from preferentially extending along the carbon layer interface (reduced energy dissipation), ensuring that cracks tend to extend through the boron carbide grains (high energy dissipation), thereby superimposing and improving the flexural strength of the boron carbide ceramics.

[0082] That is, the increase of 3% nickel-yttrium oxide composite balls is equivalent to shifting the threshold value of titanium carbide content in this aspect to the right. The flexural strength of the boron carbide ceramic (Comparative Example 1) obtained with 10% titanium carbide is greater than the flexural strength of the boron carbide ceramic (Comparative Example 2) obtained with 18% titanium carbide. After adding 3% nickel-yttrium oxide composite balls, the flexural strength of the boron carbide ceramic (Comparative Example 3) obtained with 10% titanium carbide and the flexural strength of the boron carbide ceramic (Example 1) obtained with 18% titanium carbide are both increased, but the increase is different, so that the flexural strength of the boron carbide ceramic (Example 1) obtained with 18% titanium carbide is greater than the flexural strength of the boron carbide ceramic (Comparative Example 3) obtained with 10% titanium carbide.

[0083] Specifically, by comparing Comparative Example 2, Comparative Example 4 and Example 1, it can be seen that the addition of 1.5% nano-nickel powder and 1.5% nano-yttrium oxide can significantly improve the flexural strength of the obtained boron carbide ceramic; the nickel-yttrium oxide composite balls of the present invention are made of nano-nickel powder and nano-yttrium oxide, which can further improve the flexural strength of the obtained boron carbide ceramic.

[0084] This is because the nickel-yttrium oxide composite balls are prepared by using an ethanol medium wet grinding process, and a sub-nanometer to several-nanometer physical contact interface is constructed between nickel and yttrium oxide through liquid phase interface regulation, and the spacing between the two is precisely matched, effectively enhancing the synergistic effect.

[0085] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing boron carbide ceramics, characterized in that: The steps include: S1. Mixing, by mass percentage, 76.5%-81.5% of boron carbide, 16%-20% of titanium carbide, and 2.5%-3.5% of nickel-yttrium oxide composite balls, and drying to obtain a mixed powder; S2. Add a binder to the mixed powder obtained in S1, granulate, and press into a mold at a pressure of 330-350 MPa to obtain a mold; S3. Place the die obtained in S2 in a carbon tube furnace, and hot press sinter under inert gas protection at 2150-2200° C. and a load of 25-35 MPa for 1-1.2 hours, and then cool to room temperature in the furnace to obtain the boron carbide ceramic.

2. The method for preparing boron carbide ceramics according to claim 1, wherein: The preparation method of the nickel-yttrium oxide composite ball is as follows: nano nickel powder and nano yttrium oxide are mixed in a mass ratio of (1-1.2):1, added into a ball mill, wet ball milled, filtered, dried, ground, and sieved to obtain the nickel-yttrium oxide composite ball.

3. The method for preparing boron carbide ceramics according to claim 2, wherein: In the wet ball milling treatment, ethanol is used as the medium, the ball-to-material ratio is (4-5):1, the rotation speed is 220-270 rpm, and the ball milling time is 3.5-4 hours.

4. The method for preparing boron carbide ceramics according to claim 1, 2 or 3, characterized in that: The particle size of the nickel-yttrium oxide composite ball is 1-3 μm.

5. The method for preparing boron carbide ceramics according to claim 1, wherein: The particle size of the boron carbide is 3-5 μm, and the particle size of the titanium carbide is 1-3 μm.

6. The method for preparing boron carbide ceramics according to claim 1, wherein: In S2, the binder is a polyvinyl alcohol aqueous solution with a mass concentration of 3.5%-4.5%; the mass of the binder is 6%-8% of the mass of the mixed powder.

7. The method for preparing boron carbide ceramics according to claim 1, wherein: In S1, the specific operation of drying is: placing the mixed powder in a vacuum drying oven and drying at 95-100° C. for 30-36 hours.

8. A boron carbide ceramic, characterized in that: The method is prepared according to any one of claims 1 to 7.

9. An application of boron carbide ceramics, characterized in that: The boron carbide ceramic is prepared by the preparation method according to any one of claims 1 to 7, and the boron carbide ceramic is used for chemical machinery sealing rings.

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