Fabricating silicon carbide fiber tows, involves loading fixture along with polycarbosilane fiber tows in furnace, evacuating furnace, dwelling and detaching flexible tapes/fibers to obtain fabricated fiber tows, cutting to obtain tows of required length, and laying of tows over fixture to stabilize
	PRASAD N E; GUPTA R K; CHAKRABORTY J; AGNIHOTRI A; KUMAR A; MISRA M K; MISHRA R; KUMAR S
	2023-08-02
专利权人	DEFENCE RES & DEV ORG (INIA-C)
申请日期	2023-08-02
专利号	IN202311051860-A
成果简介	NOVELTY - Fabricating SiC fiber tows, involves (a) synthesizing of a polycarbosilane by reacting dried polydimethylsilane powder, PBDSO powder of particle size lower than 75 microns, and liquid polycarbosilane of number average molecular weight between 400-600 grams per mole in the ratio 100:0.1-0.6:20 at 340-490℃ under atmospheric press, (b) melt spinning of the polycarbosilane lump of a size of 50-500 mm3 at the temperature of 250-320℃ and at low pressure of 2-5 atmospheres, (c) winding the molten polycarbosilane (PCS) fibers over a drum of a diameter 100-250 mm at 100-500 revolution per minute (RPM) to make tows having 2000-4000 filaments of a diameter less than 25 microns, (d) cutting the fibers tows from the drum to obtain tows of the required length, and (e) laying of the tows over a fixture to stabilize and to achieve an oxidative mass pickup in a range of 8-10 wt.%. USE - Method for the fabricating SiC fiber tows. ADVANTAGE - The fabrication of high strength, fine diameter, long SiC fiber tows using atmospheric pressure route polycarbosilane (PCS) and hybrid stabilization method containing iodine oxidation followed by vacuum pyrolysis. The PCS synthesized at atmospheric pressure is having adequately low viscosity and sufficiently high molecular weight with low polydispersity. The PCS fibers were stabilized under controlled conditions using air and oxygen in such a way that the oxidative mass pickup was contained within 10 wt.% and fibers do not fuse during high-temperature pyrolysis. The method provides simple, cost effective, and scalable method to produce/fabricate high strength, fine diameter, long SiC fiber tows. The PCS is synthesized at an atmosphere pressure which has a sufficiently high molecular weight and a moderate softening point, mounted on the fixture in such a way that all the filaments get stabilized uniformly and provide stabilized fibers which are bonded with the flexible graphite tapes using the high char resin material. DETAILED DESCRIPTION - Fabricating SiC fiber tows, involves (a) synthesizing of a polycarbosilane by reacting dried polydimethylsilane powder, PBDSO powder of particle size lower than 75 microns, and liquid polycarbosilane of number average molecular weight between 400-600 grams per mole in the ratio 100:0.1-0.6:20 at 340-490℃ under atmospheric press,(b) melt spinning of the polycarbosilane lump of a size of 50-500 mm3 at 250-320℃ and at low pressure of 2-5 atmospheres, (c) winding the molten PCS fibers over a drum of a diameter 100-250 mm at 100-500 RPM to make tows having 2000-4000 filaments of a diameter less than 25 microns, (d) cutting the fibers tows from the drum to obtain tows of the required length, (e) laying of the tows over a fixture to stabilize and to achieve an oxidative mass pickup in a range of 8-10 wt.%, (f) attaching a high temperature resistant flexible tapes/fibers to the stabilized polycarbosilane fibers tow at both ends using a high char, a carbonaceous moderate temperature curable resin material, (g) curing the resin material by controlled heating in an inert atmosphere, (h) mounting of the PCS fiber tows in the fixture, (i) attaching the known mass to the ends of the PCS fiber tows to keep the SiC fibers straight and do not pose excess stress, (j) loading the fixture along with the PCS fiber tows in a furnace, (k) evacuating the furnace to attain a pressure of up to 1 x 10-2mbar, (l) raising the temperature of the furnace up to 1100-1250℃ at the rate of 10-60℃/h, (m) dwelling the furnace at the highest temperature for 2-20 hours followed by natural cooling, and (n) detaching the flexible tapes/fibers from SiC fiber tows to obtain the fabricated SiC fiber tows.
IPC 分类号	C01B-032/977 ; C04B-035/571 ; C08G-077/60 ; D01F-009/10 ; H02J-003/32
国家	印度
专业领域	材料科学
语种	英语
成果类型	专利
文献类型	科技成果
条目标识符	http://119.78.100.226:8889/handle/3KE4DYBR/20997
专题	中国科学院新疆生态与地理研究所
作者单位	DEFENCE RES & DEV ORG (INIA-C)
推荐引用方式 GB/T 7714	PRASAD N E,GUPTA R K,CHAKRABORTY J,et al. Fabricating silicon carbide fiber tows, involves loading fixture along with polycarbosilane fiber tows in furnace, evacuating furnace, dwelling and detaching flexible tapes/fibers to obtain fabricated fiber tows, cutting to obtain tows of required length, and laying of tows over fixture to stabilize. IN202311051860-A[P]. 2023.

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