Method for preparing continuous silicon carbide fiber by PCS fiber

A continuous silicon carbide and fiber technology, which is applied in the fields of fiber chemical characteristics, textiles and papermaking, can solve the problems not involved in the continuous SiC fiber, so as to reduce the generation of internal defects and surface defects, ensure continuity and avoid damage Effect

Inactive Publication Date: 2010-07-28
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

These patent documents either modify the precursor PCS or introduce other elements, or change the melt spinning conditions, or change the non-melting treatment method to prepare SiC fibers with different characterist

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] (1) PCS (Mn=1850, T m = 212-226°C) placed in the melting cylinder of the melt spinning device (the spinneret hole is 200 holes, the hole diameter is 0.2μm), heated under the protection of high-purity nitrogen and after defoaming treatment, at 290°C, 0.4 Under the pressure of MPa, spinning at a speed of 500m / min, the continuous PCS fibers spun are evenly wound on the stainless steel mesh drum, and the average diameter of the fibers is 12.5 μm; (2) the mesh drum wound with the PCS fibers is placed in a non-melting In the furnace, heat to 140°C in the air for 1 hour, then heat from 140°C to 190°C at a heating rate of 10°C / hr, and heat-preserve and oxidize for 2 hours; (3) Never melt the non-melting PCS fiber mesh cylinder Take it out of the furnace and place it in a high-temperature furnace. After vacuuming and replacing nitrogen, under the protection of high-purity nitrogen, raise the temperature to 1000°C at a heating rate of 150°C / hr and keep it warm for 2 hours for med...

Embodiment 2

[0029]The PCS fiber web cylinder that embodiment 1 step (1) is made is placed in non-melting furnace, replaces the air in the furnace with high-purity nitrogen, and with high-purity nitrogen as carrier gas with the flow rate of 10ml / min / g the ring Bubble hexene into the system, rapidly heat up to about 140°C, then raise the temperature to 250°C at a rate of 10°C / hr, then continue to heat up to 350°C at a rate of 20°C / hr, and keep it warm for 2 hours; the non-melting PCS The fiber mesh cylinder is taken out from the non-melting furnace and placed in a high-temperature furnace. After vacuuming and replacing nitrogen, under the protection of high-purity nitrogen, the temperature is raised to 1050°C at a heating rate of 180°C / hr and kept for 1.5 hours for medium-temperature pre-firing ; After the furnace temperature is cooled, take out the pre-burned fiber drum, place it on the unwinding device, and unwind continuously to obtain continuous pre-burned fibers; place 6 bundles of pre-...

Embodiment 3

[0032] The PCS fiber web cylinder that embodiment 1 step (1) obtains is placed in the irradiation device, with the air in the high-purity helium replacement device, the electron beam (average beam intensity is 1.0mA) that produces with 10MeV linear electron accelerator Carry out irradiation, control the irradiation time so that the cumulative irradiation dose reaches 10.5Mgy, and then perform annealing treatment in a helium flow at 300°C for 1 hour; take the non-melting PCS fiber mesh cylinder out of the non-melting furnace and place it in a high-temperature furnace , after vacuuming and replacing nitrogen, under the protection of high-purity nitrogen, heat up to 950°C at a heating rate of 120°C / hr and keep it warm for 2.5 hours for medium-temperature pre-firing; Put it on the unwinding device, unwind continuously to obtain continuous pre-burned fibers; put 6 bundles of pre-fired fibers obtained in this way on the wire rack, and then continuously pass through 1300°C at a speed ...

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Abstract

The invention relates to a method for preparing continuous silicon carbide fiber by a PCS fiber. In the method, after the PCS melting spinning, a screen roller wound with the continuous PCS fiber is treated by the infusible process, is pre-sintered at the intermediate temperature of 1,000 DEG C and then is unwound; finally, the treated continuous PCS fiber is continuously sintered at the high temperature of 1,200-1,900 DEG C after the concentration of beam and the stranding. The method avoids that the PCS fiber is damaged in the unwinding or in the process the contact of the PCS fiber and a guide roller and other machines, ensures the continuity and the uniform performance of a SiC fiber and can be used for preparing the SiC fibers in different types.

Description

technical field [0001] The present invention relates to a method for preparing continuous silicon carbide fibers from polycarbosilane (PCS) fibers. Background technique [0002] Silicon carbide fibers have important application values ​​in high-tech fields such as aviation, aerospace, nuclear industry, and weaponry because of their 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 pyrolysis, rearrangement and polycondensation of organosilicon polymers is used as a precursor, and continuous PCS fibers are obtained through melt spinning, and the continuous PCS fibers are placed in Oxidation reaction in the air makes intermolecular cross-linking to form non-me...

Claims

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Application Information

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IPC IPC(8): D01F9/10
Inventor 宋永才王得印李义和王应德谢征芳王军
Owner NAT UNIV OF DEFENSE TECH
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