日本金属学会誌

J. Japan Inst. Metals, Vol. 56, No. 7 (1992),
pp. 785-793

Pyrolysis of Si-Ti-C-O Amorphous Fiber Coated with Oxide Film

Toshio Shimoo1, Ken-ichi Kakimoto1 and Kiyohito Okamura1

1Department of Metallurgical Engineering, College of Engineering, University of Osaka Prefecture, Sakai

Abstract:

The pyrolysis of Si-Ti-C-O amorphous fiber (Tyranno fiber) coated with oxide film was investigated at temperatures between 1573 and 1773 K. After the oxide film was formed around the fiber in an O2 gas stream, the atmosphere gas was changed from O2 to Ar. During this heat treatment, the mass change of the fiber was measured by means of a thermobalance. The heat-treated fiber was examined with X-ray diffraction, SEM and TEM observation.
At 1773 K, the fiber coated with the oxide film pyrolyzed completely, and the growth and coarsening of β-SiC crystal was observed. At the temperatures lower than 1723 K, the size of β-SiC crystallite, to which the amorphous fiber was crystallized before it was coated with the oxide film in the O2 gas stream, remained unchanged in the Ar gas stream. The tensile strength of this fiber was from 1/5 to 1/4 as large as that of the original fiber.
If adequate control is provided in the formation of the oxide film, the high-temperature strength of Tyranno fiber can be improved.


(Received 1992/03/10)

Keywords:

silicon-titanium-carbon-oxygen amorphous fiber (Tyranno fiber), oxide film, cristobalite, β-SiC, tensile strength of fiber, suppression of pyrolysis


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