Preparation method of SiBN fiber

A fiber and decarbonization technology, which is applied in the direction of fiber chemical characteristics, rayon chemical post-treatment, inorganic raw material rayon, etc., can solve the problems of the negative influence of the spinnability of the precursor, the damage of the fibril structure, and the low content of B elements. , to achieve the effect of improving mechanical properties, improving stability and high activity

Inactive Publication Date: 2015-08-12
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

After the B element is introduced into PCS, the B element content is generally low, and it has an adverse effect on the spinnability of the precursor
When B element is introduced during the cross-linking process, BCl 3 Such corrosive atmospheres have high requirements on equipment. In addition, due to the process of removing HCl and methyl, it will cause great damage to the structure of fibrils.

Method used

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  • Preparation method of SiBN fiber
  • Preparation method of SiBN fiber

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037]Put polycarbosilane non-melting fibers in the decarburization-nitriding system, vacuumize, then replace the gas in the system with nitrogen or argon to normal pressure, repeat at least three times; feed high-purity ammonia, heat up, and heat up system: Raise the temperature to 500°C in 2 hours, raise the temperature to 700°C at 0.95°C / min, keep it for 0.5h, raise the temperature to 800°C in 1h, and keep it for 2h. Cool down to room temperature with nitrogen / argon to obtain highly active Si-N fibers; raise the temperature to 400°C for 2 hours, feed borane into the decarburization-nitridation system for 24 hours, and cool to room temperature with nitrogen / argon; Enter high-purity ammonia gas, raise the temperature, and raise the temperature to 1350°C in 6 hours, and keep it warm for 1-2 hours. Cool to room temperature with nitrogen / argon gas. Serve.

[0038] figure 1 X-ray photoelectron energy map (XPS) for the prepared SiBN fiber. The peak at 100.5 electron volts (eV) ...

Embodiment 2

[0041] Put polycarbosilane non-melting fibers in the decarburization-nitriding system, vacuumize, then replace the gas in the system with nitrogen or argon to normal pressure, repeat at least three times; feed high-purity ammonia, heat up, and heat up system: Raise the temperature to 500°C in 2 hours, then raise the temperature to 700°C at 0.90°C / min, keep it for 0.5h, raise the temperature to 1000°C in 3 hours, and keep it for 1h. Cool down to room temperature with nitrogen / argon to obtain highly active Si-N fibers; raise the temperature to 450°C for 2 hours, pass dimethylborane into the decarburization-nitridation system for 36 hours, and cool with nitrogen / argon to Room temperature; Introduce high-purity ammonia gas, raise the temperature, raise the temperature to 1400°C for 6 hours, and keep it warm for 1 hour. Cool to room temperature with nitrogen / argon gas. Serve.

[0042] The X-photoelectron spectrum and radial B element X-ray photoelectron spectrum of the prepared Si...

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Abstract

The invention relates to a preparation method of SiBN fiber. The preparation method comprises the following steps: (1) preparing a high-activity Si-N fiber, namely adding an infusible polycarbosilane fiber into a decarburization-nitridation system, carrying out vacuumizing, replacing gas in the decarburization-nitridation system by virtue of nitrogen or argon until reaching an atmospheric pressure state, and repeating for at least three times; introducing high-purity ammonia gas, heating to 500 DEG C within 2 hours, after the temperature is increased to 700 DEG C at the speed of 0.90 DEG C / min-0.95DEG C / min, maintaining the temperature for 0.5 hour, heating until the temperature is 800-1200 DEG C at the speed of 100 DEG C / h, and maintaining the temeprature for 1-2 hours; introducing nitrogen / argon to cool to the room temperature, so as to obtain the high-activity Si-N fiber; (2) boronizing the high-activity Si-N fiber, namely heating until the temperature is 400-450 DEG C within 2 hours, introducing borane compound gas at least containing one B-H bond into the system, reacting for 24-36 hours, and introducing nitrogen / argon to cool to the room temperature; and (3) nitriding a boronized fiber, namely introducing high-purity ammonia gas, heating until the temperature is 1300-1400 DEG C within 6 hours, and maintaining the temperature for 1-2 hours; introducing nitrogen / argon to cool to the room temperature, so as to obtain the SiBN fiber. The preparation method is simple and convenient in process, low in cost and applicable to large-scale production, and existing decarburization-nitridation systems do not need to be changed.

Description

technical field [0001] The invention relates to a method for preparing SiBN fibers, in particular to a method for preparing SiBN fibers by converting polycarbosilane fibers. Background technique [0002] SiBN ceramic fiber is a new type of high temperature resistant wave transparent ceramic fiber. Based on the composite principle of materials, SiBN ceramic fibers have Si 3 N 4 The advantages of ceramic fiber and BN ceramic fiber (Si 3 N 4 Ceramic fiber has high strength and good oxidation resistance, but its high temperature resistance and dielectric properties are slightly worse; BN ceramic fiber has low dielectric constant and good high temperature stability, but its tensile strength is low, and its high temperature oxidation resistance is relatively poor. Difference). SiBN fibers with high temperature resistance, oxidation resistance, and high performance (good dielectric properties and mechanical properties) are the main direction of high temperature resistant wave-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D01F9/08D01F11/00C04B35/58C04B35/622
Inventor 谢征芳王军邵长伟宋永才王浩简科
Owner NAT UNIV OF DEFENSE TECH
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