A method for preparing continuous SIC fibers with low oxygen content without melting in air

A low oxygen content, fiber technology, applied in the direction of fiber chemical characteristics, textiles and papermaking, etc., can solve the problems of reduced fiber mechanical strength, high equipment requirements, and harsh conditions for the preparation of continuous SiC fibers with low oxygen content, so as to reduce oxygen content, The effect of low preparation cost and easy realization of industrial production

Active Publication Date: 2018-12-28
NAT UNIV OF DEFENSE TECH
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for preparing continuous SiC fibers with low oxygen content without melting in air. The strength is drastically reduced; in the existing preparation methods, the preparation conditions of continuous SiC fibers with low oxygen content are harsh and the technical problems are too high for equipment

Method used

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  • A method for preparing continuous SIC fibers with low oxygen content without melting in air

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] (1) PCS polymer (softening point is 223°C, number average molecular weight is 1.76×10 3 g / mol, molecular weight distribution coefficient is 3.43) is placed in the melting cylinder of the melt spinning device, heated to 360 ° C under the protection of an inert atmosphere, and after it is completely melted into a uniform melt, under the pressure of 300 ° C and 0.5 MPa , and draw and spin at a speed of 450m / min to obtain a whole tube of PCS fibrils with an average diameter of 12um, 1000 pieces / bundle, and a continuous length of 500m.

[0048] (2) Place the whole cylinder of PCS fibrils in an air infusible treatment device for infusibility treatment, raise to 100°C for 1 hour and keep the temperature for 2 hours, then raise the temperature to 160°C at a temperature increase rate of 5°C / hour, and at 160°C After holding for 5 hours, the temperature was lowered to room temperature to obtain non-melting fibers.

[0049] (3) The whole cylinder of infusible fibers is placed in a...

Embodiment 2

[0053] The entire cylinder of PCS fibrils obtained in the step (1) of Example 1 was placed in an air infusible treatment device for infusibility treatment, raised to 100 °C for 1 hour and kept for 2 hours, and then increased to 10 °C / hour at a heating rate. 170°C, incubating at 170°C for 2 hours and then cooling to room temperature to obtain infusible fibers. The whole cylinder of infusible fibers was placed in a graphite furnace, protected by nitrogen gas, raised to 100°C for 1 hour and kept for 1 hour, raised to 500°C at a heating rate of 60°C / hour, and then increased at a temperature of 120°C / hour. The speed was increased to 1200°C, and the temperature was kept for 0.5 hours to obtain continuous SiC fibers with low oxygen content.

[0054] The Si content of the SiC fiber prepared in this example is 56.23wt%, the C content is 33.09wt%, the O content is 7.18wt%, the average diameter is 11.9um, the tensile strength is 2.30GPa, and the Young's modulus is 202GPa.

[0055] The f...

Embodiment 3

[0057] The whole cylinder of PCS fibrils obtained in the step (1) of Example 1 was placed in an air infusible treatment device for infusibility treatment, raised to 100 °C for 1 hour and kept for 3 hours, and then increased to 15 °C / hour at a heating rate. 180°C, incubating at 180°C for 0.5 hours and then lowering to room temperature to obtain non-melting fibers. The whole cylinder of infusible fibers was placed in a graphite furnace, protected by argon gas, raised to 100 °C for 1 hour and kept at The heating rate was increased to 1100°C, and the temperature was maintained for 2 hours to obtain continuous SiC fibers with low oxygen content.

[0058] The SiC fiber prepared in this example has a Si content of 56.35wt%, a C content of 32.34wt%, an O content of 9.21wt%, an average diameter of 12.3um, a tensile strength of 2.22GPa, and a Young's modulus of 201GPa.

[0059] The fiber was kept at 1400°C in nitrogen for 1 hour and then lowered to room temperature, and the strength re...

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Abstract

The invention provides a method using air curing to prepare low-oxygen-content continuous SiC fibers. The method has the advantages that low-temperature air curing and heat crosslinking are used in a combined manner, the heat crosslinking is added after the air curing as compared with a traditional preparation method, the problem of excessively high fiber oxygen content caused by traditional preparation method merely increasing the air curing temperature is avoided, the problem of fiber doubling caused by the direct high-temperature pyrolysis after the low-temperature air curing is also avoided, and the continuous SiC fibers with oxygen content below 10wt% and good performance are prepared.

Description

technical field [0001] The invention relates to the technical field of continuous SiC fibers, in particular to a method for preparing continuous SiC fibers with low oxygen content by adopting air infusion Background technique [0002] Continuous SiC fiber has a series of excellent properties such as high strength, high modulus, high temperature resistance, oxidation resistance, creep resistance, corrosion resistance, good compatibility with ceramic matrix, etc. It is a very ideal reinforcing fiber. Some high-tech fields such as shipbuilding and nuclear industry have broad application prospects, and are strategic raw materials for weapon equipment and aerospace industry. For example, silicon carbide ceramic matrix composites reinforced by continuous SiC fibers (SiC f / SiC), which has the characteristics of high strength, low density and high service temperature. Applying it to a high-to-weight ratio engine can achieve significant weight reduction and is the best choice to r...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D01F9/10
CPCD01F9/10
Inventor 苟燕子王应德王军王浩简科
Owner NAT UNIV OF DEFENSE TECH
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