Progressive decarbonizing method of nitride fiber

A nitride and progressive technology, applied in the fields of fiber chemical characteristics, textiles and papermaking, etc., can solve the problems of fiber nano-scale damage, low ammonia utilization rate, affecting fiber mechanical properties, etc., achieve small ammonia consumption and improve Mechanical properties, the effect of improving utilization

Active Publication Date: 2017-08-01
NAT UNIV OF DEFENSE TECH
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a progressive decarburization method for nitride fibers, which solves the problem that the ammonia gas overflow produced in the preparation process of the existing nitride fibers causes nano-scale damage to the final fibers and affects the mechanical properties of the obtained fibers. ; The technical problem of low utilization rate of ammonia gas in the process of fiber preparation

Method used

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  • Progressive decarbonizing method of nitride fiber
  • Progressive decarbonizing method of nitride fiber

Examples

Experimental program
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Effect test

Embodiment 1

[0024] (1) Place 100 grams of polysilazane fiber samples in a high-temperature graphite furnace with a fiber monofilament diameter of 15 microns, vacuumize and replace high-purity nitrogen, and repeat twice; The room temperature was raised to 300°C, and high-purity ammonia gas was introduced at a flow rate of 5L / min, the pressure in the furnace was maintained at 0.2MPa, and the temperature was continued to rise to 650°C at 1°C / min, and a total of 1250L of high-purity ammonia gas was introduced; (3 ) Continue to heat up to 650°C at a heating rate of 1°C / min, stop feeding ammonia, and feed high-purity nitrogen at a flow rate of 10L / min, and heat up to 950°C at 1°C / min; 4) Continue at 5°C / min Raise the temperature to 1200°C and keep it warm for 2 hours to obtain silicon nitride ceramic fiber. The super depth-of-field microscope photo of the fiber shows that the nitride fiber is smooth and dense. GPa, elastic modulus 181GPa.

[0025] The ultra-depth-of-field microscope photo of g...

Embodiment 2

[0028] (1) Place 100 grams of polyborazane fiber samples in a high-temperature graphite furnace with a fiber monofilament diameter of 12 microns, vacuumize and replace high-purity nitrogen, and repeat twice; The room temperature was raised to 450°C, and high-purity ammonia gas was introduced at a flow rate of 10L / min, the pressure in the furnace was maintained at 0.3MPa, and the temperature was continued to rise to 650°C at 1°C / min, and a total of 1000L of high-purity ammonia gas was introduced; (3 ) stop feeding ammonia at 650°C, feed high-purity nitrogen at a flow rate of 5L / min, and raise the temperature to 950°C at 0.2°C / min; The boron nitride ceramic fiber can be obtained, the carbon content is 0.25wt%, the monofilament strength is 1.75GPa, and the elastic modulus is 156GPa.

Embodiment 3

[0030] (1) Place 100 grams of polyborosilazane fiber samples in a high-temperature graphite furnace with a fiber filament diameter of 13 microns, vacuumize and replace high-purity nitrogen, and repeat twice; (2) According to the heating rate of 1 ° C / min Raise the temperature from room temperature to 400°C, start feeding high-purity ammonia gas at a flow rate of 10L / min, keep the pressure in the furnace at 0.4MPa, continue to heat up to 650°C at 0.5°C / min, and feed a total of 2500L of high-purity ammonia gas; ( 3) Stop feeding ammonia gas at 650°C, feed high-purity nitrogen gas at a flow rate of 5L / min, and raise the temperature to 950°C at a rate of 0.5°C / min; The SiBN ceramic fiber can be obtained, the carbon content is 0.28wt%, the monofilament strength is 1.80GPa, and the elastic modulus is 165GPa.

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Abstract

The invention provides a progressive decarbonizing method of nitride fiber. The method comprises the steps of carrying out substitution reaction of ammonia gas at 300 to 650 DEG C so as to introduce amidogen for removing most of H and methyl, and then utilizing transamination reaction of the ammonia gas at 650 to 950 DEG C for eliminating alkyl participating in the reaction. Through controlling ammonia gas involvement occasion and involvement degree, progressive decarbonizing of the fiber is realized, the occurrence of a large number of nanometer defects is avoided, nitride ceramic fiber with excellent performance is obtained, and the mechanical property of the obtained fiber is improved.

Description

technical field [0001] The invention relates to the technical field of ceramic fibers, in particular to a progressive decarburization method for nitride fibers. Background technique [0002] The precursor conversion method is an important method for preparing ceramic fibers. This method makes full use of the spinning and fiber-forming characteristics of elemental organic polymers, and can obtain continuous ceramic fibers with fine diameters through inorganic conversion. By designing the composition structure of the precursor, ceramic fibers with various composition structures and properties can be prepared. At present, various types of continuous silicon carbide fibers, silicon nitride fibers, boron nitride fibers and SiBN fibers have been successfully prepared at home and abroad. Wait. The latter three nitride fibers are mostly prepared from carbon-containing precursors, and most of the carbon elements must be removed in the subsequent inorganicization process to achieve h...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D01F9/10C04B35/584C04B35/583C04B35/58C04B35/622
CPCC04B35/58C04B35/583C04B35/584C04B35/62286C04B35/6229C04B35/62295D01F9/10
Inventor 邵长伟王军王浩简科王小宙王兵
Owner NAT UNIV OF DEFENSE TECH
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