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Itatani, Kiyoshi; Hattori, Kazuhiko; Harima, D.; Aizawa, Mamoru; Okada, Isao; Davies, Ian J.; Suemasu, Hiroshi; Nozue, Akira

doi:10.1023/a:1017909430037

Cited by 24 publications

(1 citation statement)

References 13 publications

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“…Through these developments, the heat-resistances of the SiC-based fibers were remarkably increased from 1300 • C to 2000 • C, as can be seen from this table. Of these fibers, SiC-polycrystalline fibers (Tyranno SA, Hi-Nicalon Type S, and Sylramic) show the highest heat-resistance up to 2000 • C, and then have been actively evaluated for aerospace applications as SiC/SiC composites [7][8][9][10][11]. However, to extend the application field, increases in the fiber's strength is eagerly required.…”

Section: Introductionmentioning

confidence: 99%

High-Performance SiC-Polycrystalline Fiber with Smooth Surface

Usukawa

Ishikawa

2018

Ceramics

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Polymer-derived SiC-polycrystalline fibers show excellent heat-resistance up to 2000 °C, and relatively high strength. Up to now, through our research, the relationship between the strength and residual defects of the fiber, which were formed during the production processes (degradation and sintering), has been clarified. In this paper, we addressed the relationship between the production conditions and the surface smoothness of the obtained SiC-polycrystalline fiber, using three different raw fibers (Elementary ratio: Si1Al0.01C1.5O0.4~0.5) and three different types of reactors. With increase in the oxygen content in the raw fiber, the degradation during the production process easily proceeded. In this case, the degradation reactions (SiO + 2C = SiC + CO and SiO2 + 3C = SiC + 2CO) in the inside of each filament become faster, and then the CO partial pressure on the surface of each filament was considered to be increased. As a result, according to Le Chatelier’s principle, the surface degradation reaction and grain growth of formed SiC crystals would be considered to become slower. That is to say, using the raw fiber with higher oxygen content and closed system (highest CO content in the reactor), a much smoother surface of the SiC-polycrystalline fiber could be achieved. Furthermore, the similar effect obtained by simple oxidation of the SiC-polycrystalline fiber was confirmed, and the advantageous points of the aforementioned process were also considered.

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