CHARACTERISTICS OF PRECURSOR CERAMIC FIBER UNDER SEVERE ENVIRONMENTS
| Project/Area Number |
05650642
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | UNIVERSITY OF OSAKA PREFECTURE |
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Principal Investigator |
OKAMURA Kiyohito UNIVERSITY OF OSAKA PREFECTURE,COLLEGE OF ENGINEERING, 工学部, 教授 (70005974)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMOO Toshio UNIVERSITY OF OSAKA PREFECTURE,COLLEGE OF ENGINEERING,ASSOCIATE PROFESSOR, 工学部, 助教授 (10081374)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1994: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1993: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Precursor ceramic fiber / Severe environment properties / Silicon carbide ceramics / Composites / Mechanical properties / High-temperature pyrolysis / Inorganic polymer / Amorphous / セラミックス / 復号材料 / プレカーサー / セラミック繊維 / 高温熱分解挙動 / 高温酸化挙動 |
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| Research Abstract |
Precursor ceramic fibers have been produced from inorganic polymers as the precursor. Its process is melt-spinning of precursor polymer, curing and heat treatment. The fibers are amorphous and continuous fine fibers, and they have heat resistance and high tensile strength. The fibers have been expected as the reinforcement of ceramic matrix composites. The fibers contain large quantities of oxygen (more than 10wt%) coming from fiber-precessing of the oxidation-curing, but low-oxygen-type fibers (less than 1wt%) have been recently developed by curing with radiation crosslink. In this research work, mechanical properties, oxidation mechanism and high-temperature pyrolytic mechanism of the precursor fibers have been studied under the severe invironments of inert and oxidation atmosphere at temperatures of 1300ﾟ-1800ﾟC,using high-temperature furnace prepared by the GRANT-IN-AID FOR SCIENTIFIC RESEARCH (C).
Precursor ceramic fibers with lower oxygen contents were pyrolyzed more slowly when h
… More
eated in an Ar atmosphere, and SiO and CO gases evolution of the fibers due to the high temperature pyrolysis were suppressed, significantly retaining their original high strength in the comparison with that of high oxygen-contained fibers. The fibers heat-treated in a N_2 atmosphere at temperatures below 1500ﾟC have higher strength and Young's modulus than that treated in an Ar, because of a formation of the nitride layr on fiber surface.
On the other hand, the oxidation rate of the fibers followed the contracting-disc formula for diffusion control. The oxidation is considered to be controlled by the gaseous diffusion through the micropores in the silica film. The oxide film formed on the fiber surface suppressed high-temperature pyrolysis and provide considerable high-temperature strength. When the low-oxygen-types fibers were coated with more thin oxide layr in thickness, the hyrolysis of the fibers was suppressed significantly. The crystl structure in the core of the fibers changed from amorphous to beta-SiC microcrystallines. The tensile strength and Young's modulus were fairly improved by coating thin oxide layrs.
These above research results are considered to be very effective for the development of precursor ceramic fibers and the the fibers reinforced ceramic matrix composites. Less
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Report
(3 results)
Research Products
(25 results)
