Production method of silicon carbide fiber with high temperature tolerance

A technology of silicon carbide fiber and manufacturing method, which is applied in the direction of chemical characteristics of fibers, textiles and papermaking, etc., can solve the problems of difficult to obtain SiC fiber products, and achieve the effect of reducing oxygen content, convenient operation and low oxygen content

Active Publication Date: 2008-12-10
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, if too much impurity oxygen is introduced during the fiber preparation process and the fiber strength loss is too large at t

Method used

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  • Production method of silicon carbide fiber with high temperature tolerance
  • Production method of silicon carbide fiber with high temperature tolerance
  • Production method of silicon carbide fiber with high temperature tolerance

Examples

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Effect test

reference example 1

[0042] Take 1000g of polydimethylsilane and place it in a reaction kettle, and after passing through high-purity nitrogen to replace the air, slowly heat to 460°C, and keep warm at this temperature for 4 hours for pyrolysis polymerization. The crude product was dissolved in xylene and then filtered. The filtrate was distilled at about 200°C to remove the solvent and then distilled to 350°C under reduced pressure. After cooling, about 520g of light yellow resinous polycarbosilane PCS was obtained. The number average molecular weight Mn was 1840, and the softening point was 210-225°C.

Embodiment 1

[0044] Take 1,000 g of polydimethylsilane and place it in a reaction kettle. After replacing the air with high-purity nitrogen, it is slowly heated to 420° C., and thermally decomposed and polymerized at this temperature for 5 hours. The crude product was dissolved in xylene and filtered. The filtrate was distilled at about 200°C to remove the solvent. After cooling, about 550 g of light yellow resinous polycarbosilane PCS was obtained. The number average molecular weight Mn was 990 and the softening point was 110-117°C. Mixing PCS with aluminum acetylacetonate Al(acac) 3 It was co-dissolved in xylene at a mass ratio of 1:0.08, heated to 350°C while stirring under the protection of high-purity nitrogen, and reacted at 350°C for 4 hours. After distilling off small molecules, the light yellow product PACS was obtained, and its Mn was 1704, the softening point is 205-218°C.

Embodiment 2

[0046] Take 1000g of polydimethylsilane and put it in a distillation reaction kettle. After replacing the air with high-purity nitrogen, heat it slowly to 400°C, and pyrolyze it at this temperature for 4 hours, and collect the decomposition products by condensation while pyrolysis. It is a mixture of low molecular silanes (referred to as LPS), and the pyrolysis reaction yield is 74%. LPS is a transparent liquid at room temperature, with a boiling point of 60-300°C and a number-average molecular weight of 100-600. Mixing LPS with aluminum acetylacetonate Al(acac) 3 After dissolving and mixing at a mass ratio of 1:0.10, heat the reaction under the protection of high-purity nitrogen and gradually raise the temperature to 450° C., and keep the reaction at 450° C. for 4 hours. The crude product was dissolved in xylene and then filtered, heated to distill off the solvent, and then distilled under reduced pressure at 320°C to remove a small amount of low-molecular substances. After ...

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Abstract

The invention relates to a method for manufacturing silicon carbide fibre with high temperature resistance. Low molecular silane LPS is used as a raw material and has a reaction with an organic compound containing dense elements to synthesize AL, Y-containing polycarbosilane, namely PACS and PYCS; the PACS and PYCS are manufactured into continuous PACS and PYCS fibre by melt spinning; the PACS and PYCS fibre are subjected to infusible treatment to produce infusible fibre which can control the oxygen content; and the infusible fibre is calcinated and sintered at a high temperature under the protection of an inert atmosphere, thereby preparing SiC fibre with high crystallization and high temperature resistance. The method has the advantages of simple process, convenient operation, easy implementation by utilizing equipment for producing a common SiC fibre and low manufacturing cost; and a product produced by the method has the excellent characteristics of high strength, high temperature resistance, high oxidation resistance, etc. and is suitable for batch preparation in industry.

Description

technical field [0001] The invention relates to a method for manufacturing silicon carbide fibers with high temperature resistance. Background technique [0002] Silicon carbide (SiC) ceramic fiber has important application value in high-tech fields such as aviation, aerospace, nuclear industry, and weaponry because of its high strength, high modulus, high temperature resistance, oxidation resistance, and corrosion resistance. Industrially, the industrial production of continuous SiC fibers has been realized by using the organosilicon polymer-polycarbosilane (PCS) precursor conversion method. Its typical preparation process is as follows: polycarbosilane PCS obtained by high-temperature cracking, rearrangement and polycondensation of organosilicon polymers is used as a precursor, and continuous PCS fibers are prepared by melt spinning, and the continuous PCS fibers are placed in air for oxidation reaction. After intermolecular cross-linking to form non-melting fibers (calle...

Claims

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Application Information

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IPC IPC(8): D01F9/10
Inventor 宋永才杨大祥王得印
Owner NAT UNIV OF DEFENSE TECH
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