Intermediate-range order in polymer-route Si-C-O fibers by high-energy X-ray diffraction and reverse Monte Carlo modelling

Suzuya, Kentaro; Okamura, Kiyohito*; Suzuki, Kenji*; Ichikawa, Hiroshi*; Kohara, Shinji*

The local atomic structure and intermediate-range order of Si-C-O fibers produced from the pyrolysis of a polycarbosilane precursor have been investigated by high-energy (61.6 keV) X-ray diffraction (HEXRD) at SPring-8 and reverse Monte Carlo (RMC) modelling technique. In previous study (Okamura et. al., Key Eng. 352 (2007) 65), we suggest that the Si-C-O fibers basically have a network structure that consists of two tetrahedral units: SiC and SiO from the pair distribution function analysis of HEXRD data. In the network model, 3-membered ring of SiC as that in SiC crystal and 6-membered ring of SiO as that in silica glass are assumed as intermediate-range order. Thus, we carried out RMC modelling analysis with the HEXRD data to study more detailed short- and intermediate-range ordering structure. The relationship between the intermediate-range ordering and these behaviors has also been discussed.