Method for preparing SiC whiskers through interface reaction, and SiC whiskers

An interfacial reaction and whisker technology, which is applied in the field of preparation of high-performance ceramic materials, can solve the problems of small amount of SiC whiskers and long preparation time, and achieve fast heating speed, high energy utilization rate, and improved microstructure and performance. Effect

Inactive Publication Date: 2019-10-29
ZHENGZHOU UNIVERSITY OF AERONAUTICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for preparing SiC whiskers by interfacial reaction, so as to solve the problem that the amount of SiC whiskers obtained by the preparation method in the prior art is small and the preparation time is long

Method used

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  • Method for preparing SiC whiskers through interface reaction, and SiC whiskers
  • Method for preparing SiC whiskers through interface reaction, and SiC whiskers
  • Method for preparing SiC whiskers through interface reaction, and SiC whiskers

Examples

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Effect test

Embodiment 1

[0063] The method for preparing SiC whiskers by interfacial reaction in this embodiment comprises the following steps:

[0064] 1) Preparation of silica-carbon-boric acid precursor

[0065] Mix the three according to the volume ratio of tetraethyl orthosilicate, ethanol and distilled water at a ratio of 18:34:38, adjust the pH to 4 with boric acid, and stir at 80°C for 1 hour to obtain mixture A; Bioactive carbon with a particle size of less than 38 μm, stirred at 80°C for 3 hours, adjusted the pH to 8 with ammonia water, and continued to stir to obtain mixture B; filter mixture B, take the filter cake, and dry at 80°C to obtain silica-carbon- Boric acid precursor; wherein the molar ratio of carbon to silicon is 1.5:1, and the molar ratio of carbon to boric acid is 2:1; the amount of boric acid here refers to the amount of boric acid used for pH adjustment.

[0066] 2) Under the pressure of 3MPa, press the precursor obtained in step 1) into a cylindrical piece with a diameter...

Embodiment 2

[0069] The method for preparing SiC whiskers by interfacial reaction in this embodiment comprises the following steps:

[0070] 1) Preparation of silica-carbon precursor

[0071] Mix the three according to the volume ratio of ethyl orthosilicate, ethanol and distilled water as 20:36:40, adjust the pH to 4 with boric acid, and stir at 80°C for 2 hours to obtain mixture A; add coal particles to the mixture A, continue to stir for 4 hours, adjust the pH to 9 with ammonia water, and stir for 3 hours to obtain a mixture B; filter the mixture B and dry it at 100°C to obtain an amorphous silica-carbon-boric acid precursor; wherein the molar ratio of carbon to silicon is 2.5:1; the molar ratio of carbon to boric acid is 2.4:1;

[0072] 2) Under the pressure of 6MPa, press the precursor obtained in step 1) into a cylindrical piece with a diameter of 28mm and a thickness of 10mm, and then embed it in an alumina crucible with quartz sand, and place the crucible in a frequency of 2.45GHz...

Embodiment 3

[0075] The method for preparing SiC whiskers by interfacial reaction in this embodiment comprises the following steps:

[0076] 1) Preparation of silica-carbon-boric acid precursor

[0077] Mix the three according to the volume ratio of ethyl orthosilicate, ethanol and distilled water as 22:38:42, adjust the pH to 4 with boric acid, and stir at 80°C for 1.5h to obtain mixture A; take coal particles and add Mixture A, continue to stir for 4 hours, adjust the pH of the mixture to 9 with ammonia water, and obtain mixture B; filter mixture B and dry at 120°C to obtain an amorphous silica-carbon-boric acid precursor; wherein the moles of carbon and silicon The ratio is 3:1; the molar ratio of carbon to boric acid is 2.6:1;

[0078] 2) Under the pressure of 10MPa, press the precursor obtained in step 1) into a cylindrical piece with a diameter of 28mm and a thickness of 10mm, and then embed it in an alumina crucible with quartz sand, and place the crucible in a frequency of 2.45GHz...

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Abstract

The invention relates to a method for preparing SiC whiskers through an interface reaction, and the SiC whiskers, and belongs to the technical field of preparation of high-performance ceramic materials. The method for preparing the SiC whiskers through the interface reaction comprises the following steps: (1) according to the situation that the molar ratio of carbon to silicon is (1.5 to 3):1, a silicon source and a carbon source are taken to be mixed with boric acid to prepare a silicon dioxide-carbon-boric acid precursor, wherein the silicon source is silicate ester or silicon dioxide, and the carbon source is activated carbon or coal; and (2) the obtained silicon dioxide-carbon-boric acid precursor is pressed into a sheet and then buried in quartz sand to be subjected to microwave sintering, then the surface wrapped quartz sand is removed, then washing is conducted through hydrofluoric acid, and the SiC whiskers are obtained. According to the method, the adsorption property of the activated carbon can be fully utilized to form a good nuclear shell structure, the boric acid is adopted to adjust the pH of the precursor, a reaction can be accelerated through B2O3, and the couplingheat effect of microwave sintering can be fully utilized through the microwave effect to achieve rapid synthesis of the SiC whiskers.

Description

technical field [0001] The invention relates to a method for preparing SiC whiskers by interface reaction and the SiC whiskers, belonging to the technical field of preparation of high-performance ceramic materials. Background technique [0002] SiC has high strength, high hardness, high electrical conductivity and microwave absorption performance, and its chemical properties are stable, high thermal conductivity, good wear resistance, and is widely used in the fields of functional ceramics, refractory materials, and semiconductor materials. Short-fiber silicon carbide whiskers grown from high-purity silicon carbide single crystals have mechanical strength equal to the force between adjacent atoms, high temperature resistance and high strength, and are the whiskers that have been synthesized so far. The hardness is the highest and the modulus is the largest , the whisker product with the highest tensile strength and the highest heat-resistant temperature, mainly used in tough...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/62C30B29/36C30B1/10
CPCC30B1/10C30B29/36C30B29/62
Inventor 张锐赵彪樊磊张瑜萍范冰冰高前程白中义陈雷明李春光郭晓琴
Owner ZHENGZHOU UNIVERSITY OF AERONAUTICS
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