Micron-sized spherical boron carbide ceramic and preparation method thereof

Abstract

The invention relates to the technical field of boron carbide ceramics, in particular to micron-sized spherical boron carbide ceramics and a preparation method thereof. The micron-sized spherical boron carbide ceramic comprises 100 parts of mixed powder and 90 parts of a mixed solution, and the mixed powder comprises 89-92 parts of boron carbide micro powder, 3 parts of silicon carbide micro powder, 2 parts of zirconium oxide micro powder, 2-5 parts of diamond micro powder and 1 part of titanium boride micro powder. The preparation method comprises the following steps: S1, preparing materials; s2, mixing the materials; s3, molding the microspheres; s4, screening is carried out; and S5, sintering. The micron-sized spherical boron carbide is narrow in particle size distribution and uniform in particle, dispersion and sliding of particle ceramic in an application system are facilitated, compact accumulation can be formed, the characteristics of high filling and low viscosity are obtained, and the wear rate of equipment such as a muller and a forming machine can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of boron carbide ceramics, in particular to a micron-level spherical boron carbide ceramic and a preparation method thereof. Background Art

[0002] Boron carbide has the characteristics of high hardness, high thermal conductivity, and high temperature resistance. It is often used as a high thermal conductivity filler for grinding wheels, organic polymers, and semiconductor manufacturing equipment parts. Among them, micron-sized spherical boron carbide ceramics have the characteristics of high specific surface area, controllable monodispersity, and adjustable porosity, which further expands its application potential in the fields of inertial confinement fusion targets, nuclear reactor deceleration components, and catalyst carriers.

[0003] The shape of the boron carbide particles prepared by the general process route is an irregular shape with sharp edges in the untreated broken state after crushing. Such powders have poor fluidity and filling amount. For thermally conductive composite materials, increasing the filling amount can obtain composite materials with higher thermal conductivity. Among various powder morphologies, spherical and quasi-spherical powders have better fluidity, which can effectively reduce the effect of fillers on the viscosity of the filling system, thereby achieving a higher filling amount. Micron-sized spherical boron carbide ceramics as thermal conductive adhesive fillers can significantly improve the thermal conductivity of the mixture, reduce the expansion coefficient, and increase the strength of the cured adhesive; the spherical shape is conducive to the dispersion and sliding of the micro-ceramic particles in the system, and forms a relatively dense stacking to obtain a high-filling, low-viscosity, and high-thermal conductive mixture.

[0004] According to the above technical status, the present application provides a micron-sized spherical boron carbide ceramic and a preparation method thereof, which are used to prepare micron-sized spherical boron carbide ceramics with uniform particle size and stronger fluidity. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a micron-sized spherical boron carbide ceramic and a preparation method thereof.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a micron-sized spherical boron carbide ceramic, the components of the raw materials are as follows in parts by weight: The invention comprises 100 parts of mixed powder and 90 parts of mixed solution, wherein the mixed powder comprises 89-92 parts of boron carbide micropowder, 3 parts of silicon carbide micropowder, 2 parts of zirconium oxide micropowder, 2-5 parts of diamond micropowder and 1 part of titanium boride micropowder; The mixed solution includes 75 parts of deionized water, 4 parts of liquid carbon black, 2 parts of polyvinyl alcohol, 8 parts of phenolic resin and 1 part of n-octanol.

[0007] As an optimization, the particle size D50 value of the boron carbide micropowder is in the range of 0.5-2μm; the particle size D50 value of the silicon carbide micropowder is in the range of 1-2μm; the particle size D50 value of the zirconium oxide micropowder is in the range of 1-2μm; the particle size D50 value of the diamond micropowder is in the range of 0.5-1μm; and the particle size D50 value of the titanium boride is in the range of 1-5μm.

[0008] As an optimization, the boron carbide powder is a boron carbide material with a boron-11 enrichment of 99%.

[0009] As an optimization, the solid content of the liquid carbon black is 20%.

[0010] A method for preparing a micron-sized spherical boron carbide ceramic, which is used for any of the above-mentioned micron-sized spherical boron carbide ceramics, comprises the following steps: S1. Ingredients: Prepare the materials in the proportion of 89-92 parts of boron carbide powder, 3 parts of silicon carbide powder, 2 parts of zirconium oxide powder, 2-5 parts of diamond powder and 1 part of titanium boride powder, and mix the powders thoroughly to obtain 100 parts of mixed powder by mass; Prepare a mixed solution in the proportion of 75 parts of deionized water, 4 parts of liquid carbon black, 2 parts of polyvinyl alcohol, 8 parts of phenolic resin and 1 part of n-octanol for later use; S2 mixing: the mixed powder and the mixed solution obtained in step S1 were added to the inside of the conical mixer, and 200 parts by mass of boron carbide grinding balls were added to the inside of the conical mixer, and mixed thoroughly for 24h to obtain a uniformly mixed slurry; S3. Microsphere forming: The slurry obtained in step S2 is put into a spray granulation device for spray granulation to obtain unsintered micron-sized boron carbide spherical particles; S4. Screening: Screening the unsintered micron-sized boron carbide spherical particles obtained in step S3 using a multi-layer vibrating screen to obtain unsintered micron-sized boron carbide spherical particles of a suitable size; S5. Sintering: The unsintered micron-sized boron carbide spherical particles obtained by screening in step S4 are dispersed and placed in a customized graphite holder, and then placed in a vacuum sintering furnace for pressureless sintering.

[0011] As an optimization, during the sintering process of step S5, the vacuum sintering furnace is evacuated during the initial heating process of sintering, and the vacuum degree is maintained at <20Pa; after the temperature in the vacuum sintering furnace is raised to 1000°C, argon gas is filled into the vacuum sintering furnace for protection, and the temperature is continued to be raised to 1750-1900°C and kept warm for 3-4 hours. After the insulation is completed, the vacuum sintering furnace is naturally cooled to room temperature, and after taking out, micron-sized spherical boron carbide ceramics with an average particle size of <50μm are obtained.

[0012] As an optimization, in step S2, the boron carbide grinding balls are cylindrical balls with a boron carbide content of more than 95% and a size of φ12 mm.

[0013] As an optimization, in step S3, the air inlet temperature of the spray granulation equipment is 240-260°C, and the atomizer speed is 170-200r / min.

[0014] As an optimization, the surface of the customized mold is uniformly provided with hemispherical grooves with a diameter of r≤100 μm, and the center points of adjacent hemispherical grooves are spaced 150 μm apart.

[0015] As an optimization, a vibration device is provided inside the vacuum sintering furnace, and the vibration device is connected to the customized mold and is used to vibrate the vibration mold so that the micron-sized boron carbide spherical particles are in a vibrating state during the sintering process.

[0016] The present invention provides a micron-sized spherical boron carbide ceramic and a preparation method thereof, which has the following advantages: The micron-sized spherical boron carbide of the present application has a narrow particle size distribution and uniform particles, which is conducive to the dispersion and sliding of the micro-ceramic in the application system, can form a relatively dense stacking, obtain high filling and low viscosity characteristics, and can reduce the wear rate of equipment such as mixers and molding machines; The micron-sized spherical boron carbide ceramics of this product use boron carbide-11 with a boron-11 enrichment of 99%, which can effectively increase the material density and improve the densification of boron carbide ceramics during the sintering process, which is conducive to the production of microspheres; Adding artificial diamond powder can effectively improve the electrical conductivity, thermal conductivity and material strength of micron-sized spherical boron carbide ceramics; The preparation method of the present application uses a vacuum sintering furnace equipped with a vibration device and a customized mold, which can keep the customized mold in a vibrating state during the sintering process, effectively avoiding the adhesion, burrs and other phenomena of micron-sized spherical boron carbide ceramics during the sintering process, and effectively improving the particle size concentration and fluidity of the micron-sized spherical boron carbide ceramics. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the micron-sized spherical boron carbide ceramic of Example 2 under a scanning electron microscope of the present invention.

[0018] Figure 2 This is a schematic diagram of the micron-sized spherical boron carbide ceramic of Example 3 of the present invention under a scanning electron microscope.

[0019] Figure 3 Axial schematic diagram of the custom-made graphite bracket for the present invention.

[0020] Figure 4 A front view schematic diagram of a custom graphite bracket of the present invention. DETAILED DESCRIPTION

[0021] A micron-sized spherical boron carbide ceramic, characterized in that the raw material components are composed of the following in parts by weight: The invention comprises 100 parts of mixed powder and 90 parts of mixed solution, wherein the mixed powder comprises 89-92 parts of boron carbide micropowder, 3 parts of silicon carbide micropowder, 2 parts of zirconium oxide micropowder, 2-5 parts of diamond micropowder and 1 part of titanium boride micropowder; The mixed solution includes 75 parts of deionized water, 4 parts of liquid carbon black, 2 parts of polyvinyl alcohol, 8 parts of phenolic resin and 1 part of n-octanol.

[0022] The particle size D50 value of the boron carbide micropowder ranges from 0.5 to 2 μm; the particle size D50 value of the silicon carbide micropowder ranges from 1 to 2 μm; the particle size D50 value of the zirconium oxide micropowder ranges from 1 to 2 μm; the particle size D50 value of the diamond micropowder ranges from 0.5 to 1 μm; and the particle size D50 value of the titanium boride ranges from 1 to 5 μm.

[0023] The boron carbide powder is a boron carbide material with a boron-11 enrichment of 99%.

[0024] The solid content of the liquid carbon black is 20%.

[0025] A method for preparing micron-sized spherical boron carbide ceramics comprises the following steps: S1. Ingredients: Prepare the materials in the proportion of 89-92 parts of boron carbide powder, 3 parts of silicon carbide powder, 2 parts of zirconium oxide powder, 2-5 parts of diamond powder and 1 part of titanium boride powder, and mix the powders thoroughly to obtain 100 parts of mixed powder by mass; Prepare a mixed solution in the proportion of 75 parts of deionized water, 4 parts of liquid carbon black, 2 parts of polyvinyl alcohol, 8 parts of phenolic resin and 1 part of n-octanol for later use; S2 mixing: the mixed powder and the mixed solution obtained in step S1 were added to the inside of the conical mixer, and 200 parts by mass of boron carbide grinding balls were added to the inside of the conical mixer, and mixed thoroughly for 24h to obtain a uniformly mixed slurry; The boron carbide grinding balls are cylindrical balls with a boron carbide content of more than 95% and a size of φ12 mm; S3. Microsphere forming: The slurry obtained in step S2 is put into a spray granulation device for spray granulation, wherein the air inlet temperature of the spray granulation device is 240-260°C, and the atomizer speed is 170-200r / min to obtain unsintered micron-sized boron carbide spherical particles; S4. Screening: Screening the unsintered micron-sized boron carbide spherical particles obtained in step S3 using a multi-layer vibrating screen to obtain unsintered micron-sized boron carbide spherical particles of a suitable size; Multi-layer vibrating screens are used to remove undersized and oversized unsintered micron-sized boron carbide spherical particles, and ceramic ball products of different size ranges can also be obtained by this method. This process is also conducive to separating slightly adhered unsintered spherical particles by vibration, reducing the adhesion of ceramic microsphere products. According to the actual required particle size of micron-sized boron carbide spherical particles, multi-layer vibrating screens of different sizes can be selected for screening. The specific selection is based on the experience of the staff, and will not be repeated here.

[0026] S5. Sintering: The unsintered micron-sized boron carbide spherical particles obtained by screening in step S4 are dispersed and placed in a customized graphite holder, and added to a vacuum sintering furnace for pressureless sintering; The heating process of pressureless sintering is as follows: when the furnace temperature is at the starting temperature of -1000℃, the heating rate is 10-20℃ / min; then keep it warm for 1 hour; continue to heat up to 1000-1900℃, the heating rate is 4-7℃ / min, and finally keep the temperature for 3-4h, and then slowly cool the furnace to room temperature. When the temperature in the furnace is below 1000℃, the furnace is in a vacuum state, and the vacuum degree is <20KPa; when the temperature in the furnace is above 1000℃, argon gas is filled for protection, and the furnace is at normal pressure.

[0027] During the initial heating process of sintering, the vacuum sintering furnace is evacuated to maintain a vacuum degree of <20Pa; after the temperature in the vacuum sintering furnace is raised to 1000°C, argon gas is filled into the vacuum sintering furnace for protection, and the temperature is continued to be raised to 1750-1900°C, and the temperature is kept for 3-4 hours. After the insulation is completed, the vacuum sintering furnace is naturally cooled to room temperature, and micron-sized spherical boron carbide ceramics with an average particle size of <50μm are obtained after being taken out; The vacuum sintering furnace is provided with a vibration device inside, and the vibration device is connected to the customized mold and is used to vibrate the vibration mold so that the micron-sized boron carbide spherical particles are in a vibrating state during the sintering process; The surface of the customized graphite bracket is uniformly provided with hemispherical grooves with a diameter of r≤100 μm, and the center points of adjacent hemispherical grooves are spaced 150 μm apart.

[0028] The groove diameter of the customized graphite bracket can be manufactured and selected according to actual production requirements. In the embodiment of the present application, a customized graphite bracket with r=100 μm is used. Embodiment 1:

[0029] A micron-sized spherical boron carbide ceramic, the raw materials of which include 89 parts of boron carbide micropowder, 3 parts of silicon carbide micropowder, 2 parts of zirconium oxide micropowder, 5 parts of diamond micropowder and 1 part of titanium boride micropowder; 75 parts of deionized water, 4 parts of liquid carbon black, 2 parts of polyvinyl alcohol, 8 parts of phenolic resin and 1 part of n-octanol.

[0030] A method for preparing micron-sized spherical boron carbide ceramics comprises the following steps: S1 Ingredients: Prepare 100 parts by mass of a mixed powder and 90 parts by mass of a mixed solution according to the above ratio and set aside; S2 mixing: the mixed powder and the mixed solution obtained in step S1 were added to the inside of the conical mixer, and 200 parts by mass of boron carbide grinding balls were added to the inside of the conical mixer, and mixed thoroughly for 24h to obtain a uniformly mixed slurry; The boron carbide grinding ball is a cylindrical ball with a boron carbide content of 97% and a size of φ12mm; S3. Microsphere forming: The slurry obtained in step S2 is put into a spray granulation device for spray granulation, wherein the air inlet temperature of the spray granulation device is 240°C and the atomizer speed is 170r / min; unsintered micron-sized boron carbide spherical particles are obtained; S4 screening: using a multi-layer vibrating screen with a pore size of 100μm, the unsintered micron-sized boron carbide spherical particles obtained in step S3 were screened to obtain unsintered micron-sized boron carbide spherical particles; S5. Sintering: The unsintered micron-sized boron carbide spherical particles obtained by screening in step S4 are dispersed and placed in a customized graphite holder, and added to a vacuum sintering furnace for pressureless sintering; The heating process of pressureless sintering is as follows: when the furnace temperature is at the starting temperature of -1000℃, the heating rate is 11℃ / min; then keep warm for 1 hour; continue to heat up, at 1000-1900℃, the heating rate is 4.2℃ / min, and finally keep warm for 3h, and then slowly cool the furnace to room temperature. When the temperature in the furnace is below 1000℃, the furnace is in a vacuum state with a vacuum degree of 19.1KPa; when the temperature in the furnace is above 1000℃, argon gas is filled for protection and the furnace is at normal pressure.

[0031] During the initial heating process of sintering, the vacuum sintering furnace is evacuated to maintain a vacuum degree of <20Pa; after the temperature in the vacuum sintering furnace is raised to 1000°C, argon gas is filled into the vacuum sintering furnace for protection, and the temperature is continued to be raised to 1750-1900°C and kept warm for 3 hours. After the insulation is completed, the vacuum sintering furnace is naturally cooled to room temperature, and micron-sized spherical boron carbide ceramics are obtained after being taken out; During the sintering process, the vibration mold is vibrated by a vibration device, so that the micron-sized boron carbide spherical particles are in a vibrating state during the sintering process. Embodiment 2:

[0032] A micron-sized spherical boron carbide ceramic, the raw materials of which include 90.5 parts of boron carbide micropowder, 3 parts of silicon carbide micropowder, 2 parts of zirconium oxide micropowder, 3.5 parts of diamond micropowder and 1 part of titanium boride micropowder; 75 parts of deionized water, 4 parts of liquid carbon black, 2 parts of polyvinyl alcohol, 8 parts of phenolic resin and 1 part of n-octanol.

[0033] A method for preparing micron-sized spherical boron carbide ceramics comprises the following steps: S1 Ingredients: Prepare 100 parts by mass of a mixed powder and 90 parts by mass of a mixed solution according to the above ratio and set aside; S2 mixing: the mixed powder and the mixed solution obtained in step S1 were added to the inside of the conical mixer, and 200 parts by mass of boron carbide grinding balls were added to the inside of the conical mixer, and mixed thoroughly for 24h to obtain a uniformly mixed slurry; The boron carbide grinding balls are cylindrical balls with a boron carbide content of 97% and a size of φ12 mm; S3. Microsphere forming: The slurry obtained in step S2 is put into a spray granulation device for spray granulation, wherein the air inlet temperature of the spray granulation device is 260°C and the atomizer speed is 200r / min; unsintered micron-sized boron carbide spherical particles are obtained; S4. Screening: Screening the unsintered micron-sized boron carbide spherical particles obtained in step S3 using a multi-layer vibrating screen to obtain unsintered micron-sized boron carbide spherical particles of a suitable size; S5. Sintering: The unsintered micron-sized boron carbide spherical particles obtained by screening in step S4 are dispersed and placed in a customized graphite holder, and added to a vacuum sintering furnace for pressureless sintering; The heating process of pressureless sintering is as follows: when the furnace temperature is at the starting temperature of -1000℃, the heating rate is 19.4℃ / min; then keep it warm for 1 hour; continue to heat up to 1000-1900℃, the heating rate is 6.7℃ / min, and finally keep the temperature for 4 hours, and then slowly cool the furnace to room temperature. When the temperature in the furnace is below 1000℃, the furnace is in a vacuum state with a vacuum degree of 19.2KPa; when the temperature in the furnace is above 1000℃, argon gas is filled for protection and the furnace is at normal pressure.

[0034] During the initial heating process of sintering, the vacuum sintering furnace is evacuated to maintain a vacuum degree of <20Pa; after the temperature in the vacuum sintering furnace is raised to 1000°C, argon gas is filled into the vacuum sintering furnace for protection, and the temperature is continued to be raised to 1750-1900°C and kept warm for 4 hours. After the insulation is completed, the vacuum sintering furnace is naturally cooled to room temperature, and micron-sized spherical boron carbide ceramics are obtained after being taken out; The vibration mold is vibrated by a vibration device, so that the micron-sized boron carbide spherical particles are in a vibrating state during the sintering process. Embodiment 3:

[0035] A micron-sized spherical boron carbide ceramic, the raw materials of which include 92 parts of boron carbide micropowder, 3 parts of silicon carbide micropowder, 2 parts of zirconium oxide micropowder, 2 parts of diamond micropowder and 1 part of titanium boride micropowder; 75 parts of deionized water, 4 parts of liquid carbon black, 2 parts of polyvinyl alcohol, 8 parts of phenolic resin and 1 part of n-octanol.

[0036] A method for preparing micron-sized spherical boron carbide ceramics comprises the following steps: S1 Ingredients: Prepare 100 parts by mass of a mixed powder and 90 parts by mass of a mixed solution according to the above ratio and set aside; S2 mixing: the mixed powder and the mixed solution obtained in step S1 were added to the inside of the conical mixer, and 200 parts by mass of boron carbide grinding balls were added to the inside of the conical mixer, and mixed thoroughly for 24h to obtain a uniformly mixed slurry; The boron carbide grinding balls are cylindrical balls with a boron carbide content of 97% and a size of φ12 mm; S3. Microsphere forming: The slurry obtained in step S2 is put into a spray granulation device for spray granulation, wherein the air inlet temperature of the spray granulation device is 250°C and the atomizer speed is 185 r / min; unsintered micron-sized boron carbide spherical particles are obtained; S4. Screening: Screening the unsintered micron-sized boron carbide spherical particles obtained in step S3 using a multi-layer vibrating screen to obtain unsintered micron-sized boron carbide spherical particles of a suitable size; S5. Sintering: The unsintered micron-sized boron carbide spherical particles obtained by screening in step S4 are dispersed and placed in a customized graphite holder, and added to a vacuum sintering furnace for pressureless sintering; The heating process of pressureless sintering is as follows: when the furnace temperature is at the starting temperature of -1000℃, the heating rate is 15.1℃ / min; then keep it warm for 1 hour; continue to heat up to 1000-1900℃, the heating rate is 5.3℃ / min, and finally keep the temperature for 3.5h, and then slowly cool the furnace to room temperature. When the temperature in the furnace is below 1000℃, the furnace is in a vacuum state with a vacuum degree of 19.6KPa; when the temperature in the furnace is above 1000℃, argon gas is filled for protection and the furnace is at normal pressure.

[0037] During the initial heating process of sintering, the vacuum sintering furnace is evacuated to maintain a vacuum degree of <20Pa; after the temperature in the vacuum sintering furnace is raised to 1000°C, argon gas is filled into the vacuum sintering furnace for protection, and the temperature is continued to be raised to 1750-1900°C and kept warm for 3.5 hours. After the insulation is completed, the vacuum sintering furnace is naturally cooled to room temperature, and micron-sized spherical boron carbide ceramics are obtained after being taken out; The vibration mold is vibrated by a vibration device, so that the micron-sized boron carbide spherical particles are in a vibrating state during the sintering process.

[0038] Comparative Example 1: Ordinary boron carbide was used, and the remaining raw material ratios and process parameters were the same as those in Example 1.

[0039] Comparative Example 2: The raw material ratio and process parameters of Example 1 were adopted, a flat graphite holder was used, and no customized graphite holder was used.

[0040] Comparative Example 3: The raw material ratio and process parameters of Example 1 were adopted, but no vibration device was used.

[0041] Comparative Example 4: The raw material ratio and process parameters of Example 1 were adopted, but no customized graphite holder and vibration device were used.

[0042] Examples 1-3 and Comparative Examples 1 and 3 all use a customized graphite holder with r=100 μm, Comparative Example 2 uses a common flat graphite holder, and Comparative Example 4 uses a common flat graphite holder. The mold is in a stationary state during the sintering process.

[0043] Table 1. Experimental index data table of micron-sized spherical boron carbide ceramics obtained in Examples 1-3 and Comparative Examples 1-4.

[0044]

[0045] According to the above table, compared with Example 3, adding more diamonds in Example 1 is beneficial to improving the density and thermal conductivity of the product within a reasonable mass fraction range.

[0046] Compared with comparative example 1, the micron-sized spherical boron carbide of embodiment 1 has a high density, is more suitable for use as a thermal conductive adhesive filler, and has relatively excellent density parameters.

[0047] By comparing Example 1 with Comparative Examples 2-4, it can be seen that the spherical boron carbide ceramics prepared by the method for preparing micron-sized spherical boron carbide ceramics of the present application can avoid the adhesion between microspheres and the burrs generated after the adhesion and fracture as much as possible, can achieve a finer particle size, and has the characteristics of a high spheroidization rate, and its fluidity performance is also better; Combination Figure 1 and Figure 2 It can be seen that the micron-sized spherical boron carbide ceramics prepared by the preparation method of the micron-sized spherical boron carbide ceramics of the present application have the characteristics of high spheroidization rate, can basically achieve round or nearly round shape, few surface burrs, high dispersion, less adhesion, so that it has high fluidity, high filling properties and the like, the spherical shape is conducive to the dispersion and sliding of the micro-ceramic particles in the system, and forms a relatively dense stacking, thereby obtaining a mixture with high filling, low viscosity and high thermal conductivity; the mixture can greatly reduce the wear of equipment such as mixers, molding machines and molds, and can extend the service life of the equipment.

[0048] At the same time, this product has the advantages of high fluidity and high thermal conductivity. When used as a thermal conductive adhesive filler, it can significantly improve the thermal conductivity of the mixture, reduce the expansion coefficient, and increase the strength of the adhesive after curing.

[0049] The above-mentioned specific embodiments are only specific cases of the present invention. The patent protection scope of the present invention includes but is not limited to the product form and style of the above-mentioned specific embodiments. Any micron-sized spherical boron carbide ceramic and its preparation method that conform to the claims of the present invention and any appropriate changes or modifications made thereto by ordinary technicians in the corresponding technical field shall fall within the patent protection scope of the present invention.

Claims

1. A micron-sized spherical boron carbide ceramic, characterized in that: The components of the raw materials are composed as follows according to weight parts: The invention comprises 100 parts of mixed powder and 90 parts of mixed solution, wherein the mixed powder comprises 89-92 parts of boron carbide micropowder, 3 parts of silicon carbide micropowder, 2 parts of zirconium oxide micropowder, 2-5 parts of diamond micropowder and 1 part of titanium boride micropowder; The mixed solution includes 75 parts of deionized water, 4 parts of liquid carbon black, 2 parts of polyvinyl alcohol, 8 parts of phenolic resin and 1 part of n-octanol.

2. The micron-sized spherical boron carbide ceramic according to claim 1, characterized in that: The particle size D50 value of the boron carbide micropowder ranges from 0.5 to 2 μm; the particle size D50 value of the silicon carbide micropowder ranges from 1 to 2 μm; the particle size D50 value of the zirconium oxide micropowder ranges from 1 to 2 μm; the particle size D50 value of the diamond micropowder ranges from 0.5 to 1 μm; and the particle size D50 value of the titanium boride ranges from 1 to 5 μm.

3. The micron-sized spherical boron carbide ceramic according to claim 1, characterized in that: The boron carbide powder is a boron carbide material with a boron-11 enrichment of 99%.

4. The micron-sized spherical boron carbide ceramic according to claim 1, characterized in that: The solid content of the liquid carbon black is 20%.

5. A method for preparing micron-sized spherical boron carbide ceramics, for producing the micron-sized spherical boron carbide ceramics according to any one of claims 1 to 4, characterized in that: The steps include: S1. Ingredients: Prepare the materials in the proportion of 89-92 parts of boron carbide powder, 3 parts of silicon carbide powder, 2 parts of zirconium oxide powder, 2-5 parts of diamond powder and 1 part of titanium boride powder, and mix the powders thoroughly to obtain 100 parts of mixed powder by mass; Prepare a mixed solution in the proportion of 75 parts of deionized water, 4 parts of liquid carbon black, 2 parts of polyvinyl alcohol, 8 parts of phenolic resin and 1 part of n-octanol for later use; S2 mixing: the mixed powder and the mixed solution obtained in step S1 were added to the inside of the conical mixer, and 200 parts by mass of boron carbide grinding balls were added to the inside of the conical mixer, and mixed thoroughly for 24h to obtain a uniformly mixed slurry; S3. Microsphere forming: The slurry obtained in step S2 is put into a spray granulation device for spray granulation to obtain unsintered micron-sized boron carbide spherical particles; S4. Screening: Screening the unsintered micron-sized boron carbide spherical particles obtained in step S3 using a multi-layer vibrating screen to obtain unsintered micron-sized boron carbide spherical particles of a suitable size; S5. Sintering: The unsintered micron-sized boron carbide spherical particles obtained by screening in step S4 are dispersed and placed in a customized graphite holder, and then placed in a vacuum sintering furnace for pressureless sintering.

6. The method for preparing micron-sized spherical boron carbide ceramics according to claim 5, characterized in that: During the sintering process in step S5, the vacuum sintering furnace is evacuated during the initial heating process of sintering, and the vacuum degree is maintained at <20Pa; after the temperature in the vacuum sintering furnace is raised to 1000°C, argon gas is filled into the vacuum sintering furnace for protection, and the temperature is continued to be raised to 1750-1900°C and kept warm for 3-4 hours. After the insulation is completed, the vacuum sintering furnace is naturally cooled to room temperature, and after taking out, micron-sized spherical boron carbide ceramics with an average particle size of <50μm are obtained.

7. The method for preparing micron-sized spherical boron carbide ceramics according to claim 5, characterized in that: In step S2, the boron carbide grinding balls are cylindrical balls with a boron carbide content of more than 95% and a size of φ12 mm.

8. The method for preparing micron-sized spherical boron carbide ceramics according to claim 5, characterized in that: In step S3, the air inlet temperature of the spray granulation equipment is 240-260°C, and the atomizer speed is 170-200r / min.

9. The method for preparing micron-sized spherical boron carbide ceramics according to claim 5, characterized in that: The surface of the customized graphite bracket is uniformly provided with hemispherical grooves with a diameter of r≤100 μm, and the center points of adjacent hemispherical grooves are spaced 150 μm apart.

10. The method for preparing micron-sized spherical boron carbide ceramics according to claim 5, characterized in that: The vacuum sintering furnace is provided with a vibration device inside, and the vibration device is connected to a customized graphite holder and is used to vibrate the vibration mold so that the micron-sized boron carbide spherical particles are in a vibrating state during the sintering process.

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