Silicon hexaboride ceramic material as well as preparation method and application thereof

Abstract

The invention provides a silicon hexaboride ceramic material as well as a preparation method and application thereof. The preparation method comprises the following steps: providing mixed powder containing 50-80wt% of silicon hexaboride powder and 20-50wt% of glass powder, wherein the content of the silicon hexaboride powder is 50-80wt%, and the content of the glass powder is 20-50wt%; the glass powder is prepared from the following components in percentage by weight: 30 to 45 percent of phosphorus pentoxide, 20 to 30 percent of aluminum oxide, 5 to 15 percent of potassium oxide, 10 to 20 percent of sodium oxide and 5 to 10 percent of boron oxide; and in the air atmosphere, hot pressing sintering treatment is conducted on the mixed powder, the temperature of hot pressing sintering treatment enables the glass powder to be melted and lower than 600 DEG C, and the silicon hexaboride ceramic material is obtained. According to the preparation method provided by the invention, the glass powder is melted in the hot pressing sintering process and fills gaps of the silicon hexaboride powder, so that the prepared silicon hexaboride ceramic material has good formability, compactness and neutron shielding effect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of neutron shielding materials, and particularly relates to a silicon hexaboride ceramic material and a preparation method and application thereof. BACKGROUND

[0002] At present, the neutron shielding materials mainly used at home and abroad include various stainless steel, tungsten, copper and other metal materials, boron-containing and polyethylene-containing composite concrete, high-density polyethylene, epoxy resin and other polymer materials doped with boron, gadolinium, lithium and other neutron absorbing elements, and inorganic glass materials. Among them, boron is an ideal thermal neutron absorbing element, boron 10 has a high absorption cross section for neutrons in a wide energy range, although the natural abundance of boron 10 is only 19.78%, but natural boron still has a high neutron absorption cross section.

[0003] Common boron-containing materials mainly include boron-containing organic matter, elemental boron, boron-containing oxide, borate, boride and the like. Compared with other boron-containing materials, boron carbide, calcium hexaboride, silicon hexaboride and other boride ceramics have the advantages of high boron content, good thermal stability and corrosion resistance, and have a high thermal neutron absorption cross section and absorption range, and are a good neutron shielding material. For example, the prior art CN106007734A prepares a ZrB2-SiC-SiB6 ultra-high temperature ceramic, but the sintering temperature is as high as 1850-1950℃; the prior art CN117658463A uses SiO2, B2O3 and ZnO to prepare a thermal neutron shielding glass, but the preparation temperature is as high as 1350-1450℃. It can be seen that the melting point of such boride ceramics is high, the temperature required for densification by sintering process is high, the forming process is complex, and the engineering application is limited. SUMMARY

[0004] To solve all or part of the above technical problems, the present application provides the following technical solutions:

[0005] The first aspect of the present application provides a silicon hexaboride ceramic material, which comprises 50-80wt% of silicon hexaboride and 20-50wt% of oxide in terms of mass percentage.

[0006] The composition of the oxide comprises 30-45wt% of phosphorus pentoxide, 20-30wt% of aluminum oxide, 5-15wt% of potassium oxide, 10-20wt% of sodium oxide and 5-10wt% of boron oxide.

[0007] In some embodiments, the content of the silicon hexaboride in the silicon hexaboride ceramic material is 70-80wt%, and the content of the oxide is 20-30wt%.

[0008] The second aspect of the present application provides a preparation method of a silicon hexaboride ceramic material, comprising:

[0009] A mixed powder containing silicon hexaboride powder and glass powder is provided, wherein the content of the silicon hexaboride powder in the mixed powder is 50-80wt%, and the content of the glass powder is 20-50wt%; the composition of the glass powder comprises 30-45wt% of phosphorus pentoxide, 20-30wt% of aluminum oxide, 5-15wt% of potassium oxide, 10-20wt% of sodium oxide and 5-10wt% of boron oxide;

[0010] The mixed powder is subjected to a hot-pressing sintering treatment at a temperature lower than 600℃ and capable of melting the glass powder, to obtain a silicon hexaboride ceramic material.

[0011] The preparation method provided by the present application mixes the silicon hexaboride powder and the glass powder and then performs hot-pressing sintering, the glass powder is melted during the hot-pressing sintering process, and fills the gaps between the silicon hexaboride powder under the condition of external pressure, so as to improve the formability and density of the prepared silicon hexaboride ceramic material. Meanwhile, the glass powder with the above composition has a low melting point (not more than 350℃), so that the silicon hexaboride ceramic material can be formed at a relatively low temperature; and the glass powder with the above composition has the characteristic of short material property, and the viscosity changes rapidly with temperature, so as to quickly fill the gaps between the silicon hexaboride powder.

[0012] The contents of the silicon hexaboride powder and the glass powder in the mixed powder have important influence on the preparation effect. The silicon hexaboride powder is the main component of the silicon hexaboride ceramic material, provides the basic skeleton of the structure, and endows it with good chemical stability and good neutron shielding effect. If the content of the silicon hexaboride powder is too high, the material forming will be difficult, and if the content of the silicon hexaboride powder is too low, the chemical stability and neutron shielding performance of the material will be weakened. If the added amount of the glass powder is too high, the filling effect of the glass powder between the ceramic powders will not be significantly increased, but the closed porosity of the material will be increased, and the neutron shielding effect of the material will be reduced due to the reduction of boron element; if the low-melting-point glass powder is insufficient, the good filling effect cannot be produced, and the formability and density of the material are reduced. When the content of the silicon hexaboride powder is 50-80wt% and the content of the glass powder is 20-50wt%, the comprehensive effect of the formability, density and neutron shielding performance of the material is relatively excellent, and preferably, when the content of the silicon hexaboride powder in the mixed powder is 70-80wt% and the content of the glass powder is 20-30wt%, the comprehensive effect is further improved.

[0013] In some embodiments, the temperature of the hot-pressing sintering process is 400-550℃. If the temperature of the hot-pressing sintering process is too high, for example, when the temperature is higher than 600℃, the silicon hexaboride powder will react with oxygen in the air to form boron oxide and silicon dioxide. Therefore, in order to achieve the effect of filling the glass powder into the gaps of the silicon hexaboride powder, the temperature of the hot-pressing should be higher than the melting temperature of the low-melting-point glass powder and lower than the reaction temperature of the silicon hexaboride powder in the air. Through comprehensive research of the present application, it is found that the temperature range of 400-550℃ is more suitable, and further preferably 500℃. If the low-melting-point glass powder is not added, the subsequent hot-pressing sintering process cannot obtain bulk silicon hexaboride ceramic material because the silicon hexaboride powder cannot be sintered at this temperature condition and only accumulates together, which is easy to break after demolding.

[0014] In some embodiments, the pressure of the hot-pressing sintering process is 50-150MPa. The pressure of the hot-pressing sintering process has an effect on the density of the material. If the sintering pressure is low or the sintering process is carried out without external pressure, the filling effect of the molten glass powder in the pores of the silicon hexaboride powder is not ideal, and the material density is poor. Increasing the forming pressure can effectively reduce the apparent porosity of the material, but at the same time, it will also increase the closed porosity of the material. Through systematic research of the present application, it is found that the pressure of the hot-pressing sintering process in the range of 50-150MPa is more suitable, and further preferably 100MPa.

[0015] In some embodiments, the preparation method comprises: heating at a heating rate of 5-10℃ / min to the temperature required for the hot-pressing sintering process, for example, heating to 400-550℃.

[0016] In some embodiments, the holding time of the hot-pressing sintering process is 5-10min.

[0017] In some embodiments, the hot-pressing sintering process is carried out in an air atmosphere.

[0018] In some embodiments, the particle size of the silicon hexaboride powder is 1-3μm. The purity of the silicon hexaboride powder is preferably more than 99wt%.

[0019] In some embodiments, the particle size of the glass powder is 20μm or less, and preferably 5-15μm. The purity of the glass powder is preferably more than 99wt%.

[0020] In some embodiments, the melting point of the glass powder is 300-350℃.

[0021] In some embodiments, the preparation method comprises: after mixing the silicon hexaboride powder and the glass powder, adding a solvent for wet ball milling to obtain the uniformly mixed mixed powder.

[0022] In some embodiments, the mass ratio of the total mass of the silicon hexaboride powder and the glass powder to the mass of the solvent is 1:1-1:3.

[0023] In some embodiments, the ball milling time is 1-3h.

[0024] In some embodiments, the ball milling speed is 200-400r / min.

[0025] In some embodiments, the solvent comprises one or more of a combination of ethanol, water, and acetone.

[0026] In some embodiments, the preparation method further comprises, after the wet ball milling is completed, removing the solvent, and sieving the mixed powder with a particle size of 100-250 mesh for the hot-pressing sintering treatment.

[0027] The third aspect of the present application provides a silicon hexaboride ceramic material prepared by any one of the preparation methods.

[0028] The fourth aspect of the present application provides the use of the silicon hexaboride ceramic material of any one of the technical solutions as a neutron shielding material or for preparing a structure with a neutron shielding function.

[0029] Compared with the prior art, the present application has at least the following beneficial effects:

[0030] (1) The present application mixes a certain amount of glass powder with silicon hexaboride powder for hot-pressing sintering, so that the glass powder melts under the temperature conditions of hot-pressing sintering, and the molten glass powder fills the gaps between the silicon hexaboride powder under the condition of external pressure, thereby improving the formability and density of the prepared silicon hexaboride ceramic material.

[0031] (2) The glass powder used in the present application has the characteristics of low melting temperature (not more than 350℃) and short material property, and the viscosity changes rapidly with temperature, which can quickly fill the gaps between the silicon hexaboride powder, achieving the purpose of low-temperature and low-cost forming.

[0032] (3) The raw material of the low-melting-point glass powder used in the present application is abundant and low in price, which reduces the raw material cost of the silicon hexaboride ceramic; and the preparation method is simple, which realizes the low-temperature forming of the silicon hexaboride ceramic through heating and pressing at the same time, and lays a foundation for mass production of the silicon hexaboride ceramic material. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only constitute some embodiments described in the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0034] Figure 1a 、 Figure 1b are scanning electron microscope images of the silicon hexaboride ceramic neutron shielding material prepared in Embodiment 1 under different magnifications;

[0035] Figure 2 is a physical photograph of the silicon hexaboride ceramic neutron shielding material prepared in Embodiment 1;

[0036] Figure 3 is a schematic diagram of a neutron transmission coefficient calculation model of the silicon hexaboride ceramic neutron shielding material used in the embodiments of the present application. DETAILED DESCRIPTION

[0037] The technical solutions of the present application will be described in detail below with specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present application. The specific functional details disclosed herein should not be interpreted as limiting, but only as a basis for the claims and for teaching those skilled in the art to employ the representative basis of the present application in different ways in any appropriate detailed embodiment.

[0038] In addition, unless otherwise specified, the various raw materials used in the following examples can be obtained from the market or other sources, and the various production and testing equipment used is known in the art, and the testing methods used are also known in the art.

[0039] Embodiment 1

[0040] The present embodiment provides a silicon hexaboride ceramic neutron shielding material and a preparation method thereof, specifically comprising the following steps:

[0041] S1, 15g of silicon hexaboride powder, 15g of low-melting-point glass powder and 15g of anhydrous ethanol are added to a ball mill tank, and ball milling is carried out at a speed of 300r / min for 2h to obtain a mixed powder; wherein the low-melting-point glass powder used in the present embodiment has a melting point of 350℃, and its composition is: 38wt% of phosphorus pentoxide, 25wt% of aluminum oxide, 12wt% of potassium oxide, 17wt% of sodium oxide and 8wt% of boron oxide;

[0042] S2, the mixed powder obtained in S1 is placed in an 80℃ oven and dried for 1h to remove ethanol, and then the mixed powder with a particle size of 100-250 meshes is sieved out.

[0043] S3, the mixed powder obtained in S2 was loaded into a square mold with a length x width of 50 mm x 50 mm, and then was put into a vacuum hot-pressing machine. The temperature was raised from room temperature to 500℃ at a rate of 6℃ / min under an air atmosphere at a pressure of 50 MPa, and then was kept for 5 min. The sample was cooled down with the furnace and was demolded to obtain a silicon hexaboride ceramic neutron shielding material. The silicon hexaboride ceramic neutron shielding material prepared in this example has 50wt% silicon hexaboride and 50wt% oxides derived from the low-melting-point glass powder.

[0044] Figure 1a 、 Figure 1b are scanning electron microscope images of the silicon hexaboride ceramic neutron shielding material prepared in this example under different magnifications. Figure 2 is a physical photograph of the silicon hexaboride ceramic neutron shielding material prepared in this example.

[0045] Example 2

[0046] Example 2 is basically the same as Example 1, except that in step S1 of Example 2, 18g of silicon hexaboride powder, 12g of low-melting-point glass powder and 15g of anhydrous ethanol were uniformly mixed by ball milling; the rest was the same as Example 1, which will not be repeated here. The silicon hexaboride ceramic neutron shielding material prepared in this example has 60wt% silicon hexaboride and 40wt% oxides derived from the low-melting-point glass powder.

[0047] Example 3

[0048] Example 3 is basically the same as Example 1, except that in step S1 of Example 3, 21g of silicon hexaboride powder, 9g of low-melting-point glass powder and 15g of anhydrous ethanol were uniformly mixed by ball milling; the rest was the same as Example 1, which will not be repeated here. The silicon hexaboride ceramic neutron shielding material prepared in this example has 70wt% silicon hexaboride and 30wt% oxides derived from the low-melting-point glass powder.

[0049] Example 4

[0050] The present example provides a silicon hexaboride ceramic neutron shielding material and a preparation method thereof, which specifically comprises the following steps:

[0051] S1, 21g of silicon hexaboride powder, 9g of low-melting-point glass powder and 15g of anhydrous ethanol were added to a ball mill tank and ball milled at a speed of 300r / min for 2h to obtain a mixed powder; wherein the low-melting-point glass powder used in this example has a melting point of 350℃, and its composition is: 38wt% of phosphorus pentoxide, 25wt% of aluminum oxide, 12wt% of potassium oxide, 17wt% of sodium oxide and 8wt% of boron oxide;

[0052] S2, the mixed powder obtained in S1 was put into an oven at 80℃ for 1h to remove ethanol, and then the mixed powder with particle size between 100-250 meshes was sieved out.

[0053] S3, the mixed powder obtained in S2 was put into a square mold with length x width of 50mm x 50mm, and then put into a vacuum hot-pressing machine, heated from room temperature to 500℃ at a heating rate of 6℃ / min under air atmosphere at a pressure of 100MPa, kept for 5min, and then cooled with the furnace, and the obtained silicon hexaboride ceramic neutron shielding material was demolded. The silicon hexaboride ceramic neutron shielding material prepared in this example has 70wt% of silicon hexaboride and 30wt% of oxides derived from low-melting-point glass powder.

[0054] Example 5

[0055] This example provides a silicon hexaboride ceramic neutron shielding material and a preparation method thereof, which specifically comprises the following steps:

[0056] S1, 21g of silicon hexaboride powder, 9g of low-melting-point glass powder and 15g of anhydrous ethanol were added into a ball mill tank, and ball-milled at a speed of 300r / min for 2h; wherein the low-melting-point glass powder used in this example has a melting point of 350℃, and its composition is: 38wt% of diaphosphorus pentoxide, 25wt% of aluminum oxide, 12wt% of potassium oxide, 17wt% of sodium oxide and 8wt% of boron oxide;

[0057] S2, the mixed powder obtained in S1 was put into an oven at 80℃ for 1h to remove ethanol, and then the mixed powder with particle size between 100-250 meshes was sieved out.

[0058] S3, the mixed powder obtained in S2 was put into a square mold with length x width of 50mm x 50mm, and then put into a vacuum hot-pressing machine, heated from room temperature to 500℃ at a heating rate of 6℃ / min under air atmosphere at a pressure of 150MPa, kept for 5min, and then cooled with the furnace, and the obtained silicon hexaboride ceramic neutron shielding material was demolded. The silicon hexaboride ceramic neutron shielding material prepared in this example has 70wt% of silicon hexaboride and 30wt% of oxides derived from low-melting-point glass powder.

[0059] Example 6

[0060] Example 6 is basically the same as Example 1, except that in step S1 of Example 6, the content of silicon hexaboride powder in the mixed powder is 80wt%, and the content of low-melting-point glass powder is 20wt%, and the rest is the same as Example 1, which is not repeated here. The silicon hexaboride ceramic neutron shielding material prepared in this example has 80wt% of silicon hexaboride and 20wt% of oxides derived from low-melting-point glass powder.

[0061] Example 7

[0062] Example 7 is basically the same as Example 1, with the only difference being that:

[0063] (1) The low-melting glass powder used in Example 7 has a composition of 45wt% phosphorus pentoxide, 20wt% aluminum oxide, 5wt% potassium oxide, 20wt% sodium oxide and 10wt% boron oxide;

[0064] (2) The sintering temperature in Step S3 is 400°C, and the holding time is 10 minutes.

[0065] The rest is the same as Example 1, which will not be repeated here.

[0066] The performance of the silicon hexaboride ceramic neutron shielding material obtained in Example 7 is comparable to that of Example 1.

[0067] Example 8

[0068] Example 8 is basically the same as Example 1, with the only difference being that:

[0069] (1) The low-melting glass powder used in Example 8 has a composition of 30wt% phosphorus pentoxide, 30wt% aluminum oxide, 15wt% potassium oxide, 20wt% sodium oxide and 5wt% boron oxide;

[0070] (2) The sintering temperature in Step S3 is 550°C, and the holding time is 10 minutes.

[0071] The rest is the same as Example 1, which will not be repeated here.

[0072] The performance of the silicon hexaboride ceramic neutron shielding material obtained in Example 8 is comparable to that of Example 1.

[0073] Comparative Example 1

[0074] Comparative Example 1 is basically the same as Example 1, with the only difference being that in Step S1 of Comparative Example 2, the content of silicon hexaboride powder in the mixed powder is 90wt%, and the content of low-melting glass powder is 10wt%, and the rest is the same as Example 1, which will not be repeated here. The silicon hexaboride ceramic neutron shielding material prepared in Comparative Example 1 has 90wt% silicon hexaboride and 10wt% oxides derived from low-melting glass powder.

[0075] Comparative Example 1 and Comparative Example 1 show that when the content of low-melting glass powder used is lower than the appropriate range provided by the present application, the porosity of the silicon hexaboride ceramic material prepared in Comparative Example 1 is higher.

[0076] Comparative Example 2

[0077] The difference between Comparative Example 2 and Example 1 is only that step S3 of Comparative Example 2 is not applied with external pressure, i.e. sintering is carried out under normal pressure, and the rest is the same as Example 1, which will not be repeated here.

[0078] It is found from Comparative Example 1 and Comparative Example 2 that the porosity of the silicon hexaboride ceramic material prepared in Comparative Example 2 is obviously higher, which is due to the fact that the filling effect of the molten glass powder in the pores of the silicon hexaboride powder is not ideal and the material density is poor under the condition of not applying external pressure.

[0079] The density and apparent porosity of the silicon hexaboride ceramic prepared in the above examples are determined by the Archimedes drainage method using kerosene as the test medium, and the closed porosity and porosity are calculated, and the test results are shown in Table 1.

[0080] Table 1 Performance test of silicon hexaboride ceramic

[0081]

[0082] The results in Table 1 show that with the increase of the content of low-melting-point glass powder, the apparent density of the silicon hexaboride ceramic decreases, the bulk density increases first and then decreases, the closed porosity increases, and the apparent porosity decreases significantly first and then increases slightly. When the content of low-melting-point glass powder is 40wt.%(Example 2), the porosity of the material is the lowest, and the porosity is 13.05%. The experimental results show that the low-melting-point glass powder can fill the open pores in the material after melting, and improve the density of the material. However, when the content of low-melting-point glass powder reaches a certain proportion, the filling effect of the low-melting-point glass powder between the silicon hexaboride powders is no longer significantly increased, but the closed porosity of the material is increased. Therefore, in consideration of the whole, the content of low-melting-point glass powder is preferably between 20-50wt.%.

[0083] The Monte Carlo (MCNP) program is also used to simulate and calculate the neutron transmission coefficient of the silicon hexaboride ceramic material with different proportions. Figure 3 is a schematic diagram of a neutron transmission coefficient calculation model, Figure 3 In the figure, the thickness of the shielding material d is 25cm, the distance between the neutron source and the shielding material is 100cm, R represents the radius of the shielding material, N0 represents the number of neutrons reaching the incident surface of the shielding material from the neutron source, Nr represents the number of neutrons reflected from the incident surface of the shielding material, and N represents the number of neutrons transmitted from the exit surface of the shielding material. The calculation results are shown in Table 2.

[0084] Table 2 Neutron transmission rate of silicon hexaboride ceramic

[0085]

[0086]

[0087] The results of Table 2 show that, as the content of silicon hexaboride powder in the shielding material increases, the 1MeV neutron transmission coefficient has no obvious change trend, and the 10MeV neutron transmission coefficient shows a decreasing trend; as the density of the shielding material decreases, the 1MeV neutron transmission coefficient and the 10MeV neutron transmission coefficient both increase, and the influence of the material density on the neutron transmission coefficient is more significant. When the content of silicon hexaboride powder is 100wt% and the material density is 80%, the 1MeV neutron transmission coefficient of the silicon hexaboride ceramic neutron shielding material is the highest, which is 0.0943; when the content of silicon hexaboride powder is 50wt% and the material density is 80%, the 10MeV neutron transmission coefficient of the shielding material is the highest, which is 0.3008.

[0088] In summary, the preparation method provided by the present application mixes silicon hexaboride powder and glass powder and then hot-presses and sintering, the glass powder melts in the hot-pressing and sintering process, and fills the gaps between silicon hexaboride powder under the condition of external pressure, so as to improve the formability and density of the prepared silicon hexaboride ceramic material, and in some preferred embodiments, the apparent porosity of the material can be significantly reduced, and the total porosity is less than 20%. At the same time, the glass powder with the specific composition used in the present application has a low melting point, so that the silicon hexaboride ceramic material can be formed at a lower temperature; and the glass powder with the above composition has the characteristic of short material, and the viscosity changes quickly with temperature, which can quickly fill the gaps between silicon hexaboride powder.

[0089] In addition, the present inventors have also carried out tests with other raw materials, process operations and process conditions described in the present specification with reference to the foregoing embodiments, and all ideal results have been obtained.

[0090] Aspects, embodiments, features, and examples of the present application should be considered illustrative of the present application rather than restrictive, and the scope of the present application is defined only by the claims.

[0091] Although the present application has been described with reference to the illustrative embodiments, it is understood that various changes, omissions and / or additions can be made by one skilled in the art without departing from the spirit and scope of the present application, and elements in the embodiments can be substituted with substantially equivalent elements. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the present application without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the particular embodiments disclosed, but is intended to encompass all embodiments falling within the scope of the appended claims. Furthermore, unless specifically stated, any use of the terms first, second, etc. does not indicate any order or importance, but is used for the purpose of distinguishing one element from another.

Claims

1. A silicon hexaboride ceramic material, characterized by: The silicon hexaboride ceramic material comprises 50-80 wt% of silicon hexaboride and 20-50 wt% of oxide; The composition of the oxide comprises 30-45 wt% of phosphorus pentoxide, 20-30 wt% of aluminum oxide, 5-15 wt% of potassium oxide, 10-20 wt% of sodium oxide and 5-10 wt% of boron oxide.

2. The silicon hexaboride ceramic material of claim 1, wherein: The content of the silicon hexaboride in the silicon hexaboride ceramic material is 70-80 wt%, and the content of the oxide is 20-30 wt%.

3. A method of producing a silicon hexaboride ceramic material, characterized by, It comprises: A mixed powder comprising silicon hexaboride powder and glass powder is provided, wherein the content of the silicon hexaboride powder in the mixed powder is 50-80 wt%, and the content of the glass powder is 20-50 wt%; the composition of the glass powder comprises 30-45 wt% of phosphorus pentoxide, 20-30 wt% of aluminum oxide, 5-15 wt% of potassium oxide, 10-20 wt% of sodium oxide and 5-10 wt% of boron oxide; The mixed powder is subjected to a hot-pressing sintering treatment at a temperature lower than 600 ℃ and capable of melting the glass powder, to obtain a silicon hexaboride ceramic material.

4. The method of claim 3, wherein: The temperature of the hot-pressing sintering treatment is 400-550 ℃; And / or, the pressure of the hot-pressing sintering treatment is 50-150 MPa; And / or, the preparation method comprises: heating at a heating rate of 5-10 ℃ / min to the temperature required for the hot-pressing sintering treatment; And / or, the holding time of the hot-pressing sintering treatment is 5-10 min; And / or, the hot-pressing sintering treatment is performed in an air atmosphere.

5. The method of claim 3, wherein: The content of the silicon hexaboride in the mixed powder is 70-80 wt%, and the content of the glass powder is 20-30 wt%; And / or, the particle size of the silicon hexaboride powder is 1-3 μm; And / or, the particle size of the glass powder is 5-15 μm; And / or, the melting point of the glass powder is 300-350 ℃.

6. The production method according to claim 3, characterized by, It comprises: After mixing the silicon hexaboride powder and the glass powder, a solvent is added for wet ball milling, to obtain the mixed powder uniformly mixed.

7. The method of claim 6, wherein: The mass ratio of the total mass of the silicon hexaboride powder and the glass powder to the mass of the solvent is 1:1-1:3; And / or, the ball milling time is 1-3 h; And / or, the ball milling speed is 200-400 r / min; And / or, the solvent comprises one or a combination of more than one of ethanol, water and acetone.

8. The production method according to claim 6, characterized by, It comprises: After the wet ball milling is completed, the solvent is removed, and the mixed powder with a particle size of 100-250 mesh is sieved out for the hot-pressing sintering treatment.

9. A silicon hexaboride ceramic material, characterized by, It is prepared by the preparation method of any one of claims 3-8.

10. The silicon hexaboride ceramic material of any one of claims 1, 2 or 9 for use as a neutron shielding material or for use in preparing a structure having a neutron shielding function.

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