酸化皮膜で被覆された非晶質SiC系繊維の熱安定性

抄録

Using Tyranno fiber containing 13% O (T-2), suppression of pyrolysis with oxide film was investigated at temperatures from 1573 to 1773K. The gas stream was changed to Ar, immediately after an oxide film of a given thickness was formed on the fiber in O₂. At temperatures lower than 1723K, the pyrolysis was suppressed. The core fiber crystallized slightly, and the oxide film changed from amorphous silica into cristobalite. The tensile strength was 1.26 to 1.45GPa when treated at 1723K. At 1773K, the oxide film disappeared, and the core fiber decomposed completely to β-SiC. The resulting fiber was too weak to measure the strength. These results were compared with those obtained in Tyranno fiber containing 18% O (T-1) and Nicalon fiber (NL200).