A method for preparing beryllium-containing silicon carbide ceramic fibers using gallium as a deoxidizer

A technology of silicon carbide ceramics and deoxidizer, applied in the direction of inorganic raw material rayon, etc., can solve the problems of unevenness, insufficient reaction, general stability of finished products, etc., and achieve the effect of high-efficiency deoxidation

Active Publication Date: 2021-08-17
湖南泽睿新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the biggest problem that limits the performance improvement of SiC ceramics is: excessive growth of β-SiC grains at high temperatures
The disadvantage of this operation is that the stability of the finished product is not good, the main reason is that the steric hindrance effect of polymer polycarbosilane can cause insufficient and uneven reaction between beryllium and polycarbosilane, and the performance of the resulting product is also not good. There is room for improvement
In addition, the direct use of polymer polycarbosilane as a raw material has a relatively high cost.
Patent CN107473748A provides a low-cost, high-quality method for preparing silicon carbide fibers containing beryllium; but this patent does not involve the technology of how to further reduce the oxygen content inside silicon carbide fibers

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Taking PSCS (molecular weight is 160) and beryllium acetylacetonate as raw materials, the mass proportion of the two (the proportioning described in the following examples is the mass proportion) is beryllium acetylacetonate:PSCS=10:100, 420°C of reaction temperature, The pyrolysis temperature was 500°C, and after holding the reaction for 6 hours, it was dissolved in xylene and filtered, and the filtrate was distilled under reduced pressure at 350°C for 30 minutes to obtain PBCS with a softening point of 195°C and a beryllium content of 1.31wt%. PBCS was added to the melt spinning device and degassed under the protection of high-purity nitrogen, at 258 ° C, 4 × 10 5 Under the pressure of Pa, melt spinning at a speed of 300m / min to obtain a PBCS precursor with a diameter of 20μm; place the above fiber in a non-melting treatment device, and heat it to 185°C at a heating rate of 10°C per hour in an air atmosphere. ℃, keep warm for 2 hours, and cool to room temperature to o...

Embodiment 2

[0048] Other conditions are consistent with embodiment 1; The difference is:

[0049] Put the PBCS non-melting fiber in the metal gallium liquid at 80°C; ultrasonicate for 60 minutes under the condition of 45KHz; take it out to obtain the deoxidized PBCS non-melting fiber.

[0050] The obtained beryllium-containing silicon carbide fiber was placed in a metal gallium liquid at 80°C; ultrasonicated at 45KHz for 60 minutes; taken out, and tempered at 650°C for 60 minutes; the product was obtained; the tensile strength of the product was 2.7GPa, and the elastic modulus 351GPa.

Embodiment 3

[0052] Using PCS (molecular weight 300) and beryllium as raw materials, beryllium: PCS = 5:100, the reaction temperature is 430 ° C, the cracking temperature is 490 ° C, and after the reaction time of 4 hours, it is dissolved and filtered in xylene, and the filtrate is dissolved at 350 ° C. ℃ for 1 hour under reduced pressure to obtain a softening point of 202 ℃, PBCS containing 0.61wt% beryllium; PBCS is added to the melt spinning device and degassed under the protection of high-purity nitrogen, at 268 ℃, 4.5 × 10 5 Under the pressure of Pa, melt spinning at a speed of 350m / min to obtain a PBCS precursor with a diameter of 18μm; place the above fiber in a non-melting treatment device, and heat it to 180°C at a heating rate of 10°C per hour in an air atmosphere. ℃, keep warm for 2 hours, and cool to room temperature to obtain PBCS non-melting fibers;

[0053] Put the PBCS non-melting fiber in the metal gallium liquid at 90°C; treat it for 120 minutes; take it out to obtain the...

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Abstract

The invention relates to a method for preparing silicon carbide ceramic fibers containing beryllium by using gallium as a deoxidizer, and belongs to the technical field of silicon carbide fiber preparation. The present invention uses beryllium-containing SiC ceramic precursors as raw materials; through melt spinning, PBCS precursors are obtained; the PBCS precursors are subjected to non-melting treatment; the precursors after non-melting treatment are obtained; the precursors after non-melting treatment are processed Gallium bath to obtain deoxidized precursors; the temperature of the gallium bath is 29.76-100°C; the obtained deoxidized precursors are subjected to high temperature treatment, and then subjected to a gallium bath; finally tempered above 600°C to obtain finished products. The preparation process of the invention is reasonable, the obtained product has excellent performance, and is convenient for large-scale industrial application.

Description

technical field [0001] The invention relates to a method for preparing silicon carbide ceramic fibers containing beryllium by using gallium as a deoxidizer, and belongs to the technical field of silicon carbide fiber preparation. Background technique [0002] SiC ceramics have excellent properties such as high strength, high modulus, high temperature resistance, corrosion resistance, oxidation resistance, and low density. In terms of performance, SiC ceramics are the material of choice for ultra-high temperature working parts, and have a wide range of uses in high-tech fields. [0003] At present, the biggest problem that limits the improvement of the performance of SiC ceramics is: excessive growth of β-SiC grains at high temperatures. In order to solve this problem, the introduction of high melting point compounds or heterogeneous elements in the process of preparing SiC ceramic precursors to prepare SiC ceramics containing heterogeneous elements has become the mainstream...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B41/88D01F9/08C04B35/565
CPCC04B35/62281C04B41/009C04B41/4584C04B41/88D01F9/08C04B14/4687C04B41/515
Inventor 黄小忠唐云王春齐彭立华
Owner 湖南泽睿新材料有限公司
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