A B6O ceramic powder and preparation method

Abstract

The present invention relates to a B6O ceramic powder and a preparation method, comprising the following steps: mixing calcium hexaboride and boron oxide powder according to a chemical reaction stoichiometric ratio to obtain a uniformly mixed raw material; pressing the uniformly mixed raw material to obtain a raw material green body; calcining the raw material green body in a high-temperature furnace; and leaching, filtering, rinsing, and drying the calcined product to obtain the B6O ceramic powder. The present invention uses calcium hexaboride powder as the raw material, significantly reducing costs compared to the prior art using boron powder as the raw material. Furthermore, the present invention does not require high-pressure conditions and has lower process production requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic chemistry, and in particular relates to a B6O ceramic powder and a preparation method thereof. Background Art

[0002] Boron hexaoxide (chemical formula B6O) is a light element α-rhombohedral boron-rich compound. Its crystal structure (space group ) is similar to B4C, 12 Icosahedrons are connected to oxygen atoms through covalent bonds. This structure imparts numerous exceptional properties, including light weight, ultrahardness, a high melting point, high thermal conductivity, high elastic modulus, and excellent thermal stability. It is a highly promising superhard material to replace diamond and cubic boron nitride. It can be used as a cutting tool in extreme operating environments, such as mining, petrochemicals, weapons and armor, and the nuclear industry.

[0003] Currently, industrial production of B6O powder primarily involves using boron powder and boron oxide powder as raw materials, reacting under high-temperature and high-pressure conditions. However, this method is plagued by high production costs and demanding process conditions. Currently proposed methods for preparing B6O ceramic powder primarily use boron powder and boron oxide powder as raw materials, synthesizing at temperatures around 1600°C and pressures >5 GPa. However, these methods utilize high-cost raw material B, and the product contains excessive amounts of boron impurities after the reaction. Furthermore, these processes are challenging due to the stringent process conditions. Furthermore, these stringent preparation conditions also result in residual carbon in the calcium boride hexahydrate powder currently produced industrially. Existing processes for removing this residual carbon are difficult to achieve, making the production of high-purity, ultrafine calcium boride hexahydrate powder difficult to achieve with existing process conditions and raw materials. Therefore, a new B6O ceramic powder and preparation method are necessary. Summary of the Invention

[0004] In order to overcome the above problems existing in the prior art, the present invention provides a B6O ceramic powder and a preparation method thereof, which are used to solve the above problems existing in the prior art.

[0005] A method for preparing B6O ceramic powder comprises the following steps:

[0006] S1. The calcium hexaboride and boron oxide powders are mixed in a chemical reaction stoichiometric ratio to obtain a uniformly mixed raw material;

[0007] S2. The mixed raw materials are pressed to obtain a green raw material;

[0008] S3. The raw material green body is calcined in a high temperature furnace;

[0009] S4. The calcined product is leached, filtered, rinsed, and dried to obtain B6O ceramic powder.

[0010] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the molar ratio of calcium hexaboride to boron oxide is between 1:1 and 1:4.

[0011] According to the above aspects and any possible implementation, an implementation is further provided, wherein the calcination is performed under the protection of an inert atmosphere.

[0012] According to the above aspects and any possible implementation, an implementation is further provided, wherein the inert atmosphere is argon.

[0013] According to the above aspects and any possible implementation, an implementation is further provided, wherein a sample pressing machine is used for pressing in S2, and the pressure used is 10 to 100 MPa.

[0014] According to the above aspects and any possible implementation, an implementation is further provided, wherein the process conditions for the calcination in S3 are: a calcination temperature of 1000-1600° C., and a holding time of 1-5 hours.

[0015] According to the above aspects and any possible implementation, an implementation is further provided, wherein the leaching in S4 is achieved by using hydrochloric acid.

[0016] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the molar ratio of calcium hexaboride to boron oxide is 1:1.

[0017] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the molar ratio of calcium hexaboride to boron oxide is 1:2.

[0018] The present invention also provides a B6O ceramic powder, which is obtained by adopting the preparation method.

[0019] Beneficial effects of the present invention

[0020] The present invention's B6O ceramic powder and preparation method include the following steps: mixing calcium hexaboride and boron oxide powder according to a chemical reaction stoichiometric ratio to obtain a uniformly mixed raw material; pressing the uniformly mixed raw material to obtain a raw material green body; calcining the raw material green body in a high-temperature furnace; and leaching, filtering, rinsing, and drying the calcined product to obtain the B6O ceramic powder. The present invention uses calcium hexaboride powder as the raw material, significantly reducing costs compared to the prior art method using boron powder as the raw material. Furthermore, the present invention does not require high-pressure conditions and has lower production process requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flow chart of the preparation method of the present invention;

[0022] Figure 2 XRD pattern of B6O prepared in the present invention;

[0023] Figure 3 This is an electron microscope image of B6O prepared in the present invention. DETAILED DESCRIPTION

[0024] To better understand the technical solutions of the present invention, the present invention includes but is not limited to the specific embodiments described below. Similar technologies and methods should be considered within the scope of protection of the present invention. To further clarify the technical problems, technical solutions, and advantages to be solved by the present invention, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments.

[0025] It should be understood that the embodiments described herein are only a portion of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "an", "the" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0027] like Figure 1 As shown, the present invention provides a method for preparing B6O ceramic powder, comprising the following steps:

[0028] S1. The calcium hexaboride and boron oxide powders are mixed in a chemical reaction stoichiometric ratio to obtain a uniformly mixed raw material;

[0029] S2. The mixed raw materials are pressed to obtain a green raw material;

[0030] S3. The raw material green body is calcined in a high temperature furnace;

[0031] S4. The calcined product is leached, filtered, rinsed, and dried to obtain B6O ceramic powder.

[0032] Specifically, the preparation method of the present invention is as follows:

[0033] (1) Calcium hexaboride and boron oxide powder are mixed according to the chemical reaction stoichiometric ratio to obtain a uniformly mixed raw material, the purpose of which is to fully mix the raw materials, increase the contact of the reaction raw materials, and promote the reaction;

[0034] (2) The powdered raw material obtained in (1) is pressed on a tablet press to obtain a raw material green body, the purpose of which is to push the dispersed solid raw material to the maximum extent by external force to promote the reaction;

[0035] (3) Under the protection of an inert atmosphere, the raw material green body obtained in (2) is roasted in a high-temperature furnace to obtain a blocky reddish-brown pre-product, which needs further processing;

[0036] (4) In order to remove the by-products in the reaction (3), the calcined reddish-brown block pre-product is crushed, leached, filtered, rinsed, and dried to obtain B6O ceramic powder.

[0037] Furthermore, the molar ratio of calcium hexaboride to boron oxide in step (1) is between 1:1 and 1:4. Because the present invention uses low-carbon calcium hexaboride and boron oxide as raw materials, the carbon content of the calcium hexaboride in the raw materials is 1.23wt%, avoiding the use of elemental boron and the introduction of carbon, thus solving the problem of residual carbon. Furthermore, the raw materials for preparing calcium hexaboride in this process are calcium particles and boron carbide, and their cost is several tenths of that of boron powder, effectively solving the problem of excessively high cost of boron powder B in existing methods.

[0038] Furthermore, the pressure of the sample pressing process in step (2) is 10 to 100 MPa, the purpose of which is to push the dispersed solid raw materials to the maximum extent through external force to promote the reaction.

[0039] Furthermore, the roasting process described in step (3) is to keep the temperature at 1000-1600°C for 1-5 hours to obtain a reddish-brown mixed pre-product of CaB2O4 and B6O.

[0040] Furthermore, the leaching process described in step (4) can use 1 mol / L hydrochloric acid for pickling for 1 hour to remove the by-product CaB2O4, followed by filtration and vacuum drying at 150°C to obtain B6O powder.

[0041] The following uses specific embodiments to illustrate:

[0042] Example 1:

[0043] (1) Calcium hexaboride powder and boron oxide powder were weighed and mixed in a molar ratio of 1:1.

[0044] (2) The powder obtained in (1) was pressed into a green compact at a pressure of 50 MPa.

[0045] (3) Under an argon protective atmosphere, the green body obtained in (2) was placed in a crucible and heated and calcined at 1300°C for 5 hours.

[0046] (5) After the heat preservation is completed, the reaction product is cooled to room temperature in an argon atmosphere. The calcined product is leached, filtered, rinsed, and dried to obtain the product B6O ceramic powder.

[0047] Example 2:

[0048] (1) Calcium hexaboride powder and boron oxide powder were weighed and mixed in a molar ratio of 1:1.5.

[0049] (2) The powder obtained in (1) was pressed into a green compact at a pressure of 60 MPa.

[0050] (3) Under an argon protective atmosphere, the green body obtained in (2) was placed in a crucible and heated and calcined at 1400°C for 4 hours.

[0051] (5) After the heat preservation is completed, the reaction product is cooled to room temperature in an argon atmosphere. The calcined product is leached, filtered, rinsed, and dried to obtain the product B6O ceramic powder.

[0052] Example 3:

[0053] (1) Calcium hexaboride powder and boron oxide powder are weighed and mixed in a molar ratio of 1:2.

[0054] (2) The powder obtained in (1) was pressed into a green compact at a pressure of 70 MPa.

[0055] (3) Under an argon protective atmosphere, the green body obtained in (2) was placed in a crucible and heated and calcined at 1500°C for 3 hours.

[0056] (5) After the heat preservation is completed, the reaction product is cooled to room temperature in an argon atmosphere. The calcined product is leached, filtered, rinsed, and dried to obtain the product B6O ceramic powder.

[0057] The present invention also provides a B6O ceramic powder, which is obtained by the preparation method of the present invention. The prepared B6O powder is analyzed by X-ray diffraction and has a single-phase structure. The XRD pattern is as follows: Figure 2 As shown, under normal circumstances, B6O prepared under normal pressure conditions has oxygen defects, that is, B6O 1-x (x<0.28). The lattice constant of B6O prepared by the present invention is calculated, and the actual oxygen content of B6O powder reaches B6O 0.76 , therefore, it can be demonstrated that its oxygen content is greater than that of most atmospheric pressure processes.

[0058] like Figure 3 As shown in FIG, the B6O powder prepared by this process has a special porous structure, and the pores are derived from the outward diffusion of CaB6 in the cubic structure to form cavities.

[0059] The foregoing description shows and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the application concept described herein by the teachings above or by techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.

Claims

1. A method for preparing B6O ceramic powder, characterized in that: The steps include: S1. The calcium hexaboride and boron oxide powders are mixed according to the chemical reaction stoichiometric ratio to obtain a uniformly mixed raw material, wherein the molar ratio of calcium hexaboride and boron oxide is between 1:1 and 1:4; S2. The mixed raw materials are pressed to obtain a green raw material; S3. The raw material green body is calcined in a high temperature furnace, the calcination is carried out under an inert atmosphere, the calcination process conditions are: calcination temperature of 1000 ~ 1600 ℃, holding time: 1 to 5 hours; S4. The calcined product is leached, filtered, rinsed, and dried to obtain B6O ceramic powder.

2. The method for preparing B6O ceramic powder according to claim 1, characterized in that: The inert atmosphere is argon.

3. The method for preparing B6O ceramic powder according to claim 1, characterized in that: In the S2, a sample pressing machine is used for sample pressing, and the pressure used is 10-100 MPa.

4. The method for preparing B6O ceramic powder according to claim 1, characterized in that: The leaching in S4 is achieved by using hydrochloric acid.

5. The method for preparing B6O ceramic powder according to claim 1, characterized in that: The molar ratio of calcium hexaboride to boron oxide is 1:

1.

6. The method for preparing B6O ceramic powder according to claim 1, characterized in that: The molar ratio of calcium hexaboride to boron oxide is 1:

2.

7. A B6O ceramic powder, characterized in that: The B6O ceramic powder is obtained by the preparation method according to any one of claims 1 to 6.

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