Abstract
Si-Ti-C-O fiber, which is prepared by pyrolysing melt-spun polytitanocarbosilane fibers at the temperature higher than 1000°C (Yajima method), has a high tensile strength. The structural evolution of Si-Ti-C-O fibers by pyrolysis temperature between 500° and 1400°C was investigated by small-angle X-ray scattering (SAXS). The SAXS intensities of the Si-Ti-C-O fibers pyrolysed at higher than 1000°C obey the Porod law at the scattering vector higher than about 4 nm-1, while the Porod-decay cannot be observed in the SAXS intensities of the fibers pyrolysed below 800°C. The radii of gyration obtained from the SAXS intensities increase from 0.48 to 1.05 nm with increase in the pyrolysis temperature from 1000° to 1400°C. A conversion from organometallic polymer "polytitanocarbosilane" to ceramics "Si-Ti-C-O amorphous fiber" including β-SiC nano-clusters occurs drastically at the pyrolytic temperature of about 1000°C.
