Preparation of silicon oxynitrocarbide (SiONC) and of its ceramic-fibre-composites via hydrosilylation/radical polymerization/pyrolysis

A three-step preparation procedure of the silicon oxynitrocarbide (SiONC) glass was developed, for the purpose of the production of SiONC composites with inorganic fibres. At first, a stable, storable viscous liquid precursor resin (suitable for fibre impregnation) was synthesized via hydrosilylation. The liquid resin was subsequently cured via radical polymerization in the second step, and finally, the solid precursor was pyrolysed to SiONC. Two SiONC glasses, with higher and with lower oxygen content, were prepared and characterized. Weight losses during processing, the compactness (electron microscopy) of the prepared glasses, their elemental composition (energy-dispersive X-ray spectroscopy) and chemical microstructure (nuclear magnetic resonance), as well as their mechanical properties (indentation moduli and compression strength) were investigated. Finally, the three-step SiONC synthesis was successfully employed to prepare a SiONC/Nextel 720 fibre composite, which displayed very good mechanical properties.