Atomic-Scale Structure of Polymer-Route Si-C-O Fibers Observed by Synchrotron Radiation X-Ray Diffraction

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

doi:10.4028/www.scientific.net/KEM.352.65

Paper Titles

Measurement of Indentation Fracture Toughness of Silicon Nitride Ceramics: II, Effect of the Experimental Conditions
p.45

Influence of Crack Healing on Mechanical Properties of SiC Fabric / SiC- Al₂O₃ Matrix Laminates
p.49

Characterization of Mechanical Properties of Brittle Coating Systems by Various Indentation Techniques
p.53

High Performance SiC Fibers from Polycarbosilane for High Temperature Applications
p.59

Atomic-Scale Structure of Polymer-Route Si-C-O Fibers Observed by Synchrotron Radiation X-Ray Diffraction
p.65

Melt Spinnable Blend Polymers of Polycarbosilane and Polysiloxane for Synthesis of Silicon Carbide Micro Tube Structures
p.69

Mechanical Properties of SiC Processed with Nanometer-Sized Powder and Polytitanocarbosilane
p.73

Fabrication of Two Dimensional Silicon Carbide Fiber-Reinforced Silicon Carbide Composite by Electrophoretic Deposition and Hot-Pressing
p.77

Deflocculation of Alumina Suspensions Using Polyelectrolyte Dispersants
p.81

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Atomic-Scale Structure of Polymer-Route Si-C-O Fibers Observed by Synchrotron Radiation X-Ray Diffraction

Abstract:

The atomic scale structure of amorphous Si-C-O ceramics fibers produced from the pyrolysis of a polycarbosilane precursor has been investigated by X-ray diffraction using high-energy synchrotron radiation at SPring-8. First peak in the total correlation function T(r) of the amorphous and the heat-treated fibers is analyzed to consist of two contributions: Si-C (1.89 Å) and Si-O (1.61 Å) bonds. The coordination number of C and/or O around Si is about four. This suggests that the Si-C-O fibers basically have a network structure that consists of two tetrahedral units: SiC4 and SiO4. The local chemical and structural orders vary continuously in the materials from the disordered network structure of SiC4 and SiO4 tetrahedra (mixture of amorphous SiC and SiO2) to nanocrystals of SiC and SiO2, through the ternary Si-C-O solid solution which is believed to have an intermediate structure between the amorphous and crystalline states.