Silicon carbide ceramic material and preparation method thereof

A technology of silicon carbide ceramics and polycarbosilane, which is applied in the field of silicon carbide ceramic materials and their preparation, can solve problems such as low yield, and achieve the effects of reducing production costs, reducing costs, improving properties such as density and tensile strength

Active Publication Date: 2017-02-22
SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the defect of low yield when polycarbosilane is pyrolyzed into silicon carbide ceramic material in the prior art, and to provide a silicon carbide ceramic material and its preparation method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Select 50g of polycarbosilane solid particles with a number-average molecular weight of 4000, put them into a glass vacuum irradiation tube, vacuumize and isolate oxygen, place them in an electron beam conversion X source, and irradiate with X-rays with an absorbed dose of 50kGy. The dose rate is 0.1kGy / h. The yield of silicon carbide ceramic material of polycarbosilane is directly obtained by conventional thermogravimetric analysis. In thermogravimetric analysis, nitrogen is used as the carrier gas. The heating rate is 10°C / min, from room temperature to 1000°C. The pyrolysis residual weight rate is recorded as Silicon carbide ceramic material yield. The calculated yield of the silicon carbide ceramic material was 83%.

Embodiment 2

[0042] Select polycarbosilane 19g (viscous liquid) that number-average molecular weight is 300 for selection, 1g triallyl isocyanurate (TAIC), be dissolved in the 40g xylene completely, then evaporate to dryness solvent, obtain containing additive TAIC Polycarbosilane, TAIC content 5.0%. The sample was placed in a metal tray with a liquid thickness of 0.5 cm, and the tray mouth was covered with aluminum foil (air atmosphere). Put the tray containing the samples on the electron beam irradiation track, and irradiate with electron beam. The electron beam energy is 3.0MeV, the absorbed dose is 2000kGy, and the irradiation dose rate is 10kGy / s. The viscous liquid becomes solid. The yield of silicon carbide ceramic material of polycarbosilane is directly obtained by thermogravimetric analysis. In thermogravimetric analysis, nitrogen gas is used as the carrier gas. The heating rate is 10°C / min, and the temperature is raised from room temperature to 1000°C. The pyrolysis residual weig...

Embodiment 3

[0048] 20 g of polycarbosilane with a number average molecular weight of 300 was selected for use. In this embodiment, no sensitizer or solvent is added, and the remaining control conditions are the same as in Embodiment 2. The yield of the silicon carbide ceramic material was calculated to be 55%. In this embodiment, no sensitizer is added, and the processing and performance of the irradiated polycarbosilane are not affected.

[0049] Known by embodiment 2, 3, the productive rate of the embodiment 2 that adds radiation sensitizer is better than the embodiment 3 of direct irradiation, but embodiment 2 is owing to the increase of sensitizer, and the polycarbosilane after irradiation cannot be completely Dissolved in xylene, its processing, use performance become worse with respect to embodiment 3.

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Abstract

The present invention discloses a silicon carbide ceramic material and a preparation method thereof. The method comprises: (1) irradiating polycarbosilane having a number average molecular weight of 300-4000 with high energy rays, wherein the absorbed dose of the polycarbosilane is 50-2000 kGy; and (2) carrying out pyrolysis on the irradiated polycarbosilane to obtain the silicon carbide ceramic material. According to the present invention, the silicon carbide ceramic material is prepared by using the in-situ irradiation method, such that only the chemical structure of the polymer is changed, and the impurity is not introduced; the irradiation process is completely controllable and the irradiation dose can be controlled according to the raw material characteristics to achieve the best effect, such that the yield of the silicon carbide ceramic material can be significantly improved, the production cost can be reduced, the production period can be shortened, and various molding processes and the production processes of the irradiated polycarbosilane cannot be affected; and the silicon carbide ceramic material prepared by using the preparation method has advantages of uniformity, further improved temperature resistance, further improved compactness, further improved tensile strength, and other properties.

Description

technical field [0001] The invention relates to a silicon carbide ceramic material and a preparation method thereof. Background technique [0002] Silicon carbide (SiC) ceramic material is a new type of high-performance material, which has a series of advantages such as high strength, low density, high temperature resistance, oxidation resistance, and radiation resistance, and has important applications in cutting-edge manufacturing industries. For example, silicon carbide ceramic materials are used in the aerospace field to manufacture high-temperature engines and heat-resistant protective layers, and in the nuclear energy field to manufacture core structural materials, heat exchange components, and thermal sensor devices for nuclear reactors. The precursor conversion method is one of the main methods to prepare high-end silicon carbide ceramic materials, which are obtained by controlled thermal cracking of organocarbon silicon compounds (especially an organic precursor com...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/565C04B35/80C04B35/64C04B41/87
Inventor 王谋华程勇刘伟华张文礼张文发李诚吴国忠
Owner SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI
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