High-Temperature Evolution of SiC/C Products Derived from Preceramic Polymers

The products formed during thermolysis of organosilicon polymers containing unsaturated carbon-carbon bonds have been studied within the temperature range 20–1700°C by means of XRD, 13C and 29Si MAS NMR, and Raman spectroscopy. These products are distinguished by their structural instability. A continuous evolution of the products formed during organic–inorganic thermal transformation involves (i) ordering of the local surroundings of silicon atoms, the formation of a silicon carbide crystalline phase, and the transition from β to α and (ii) consumption of carbon for the completion of silicon carbide formation, carbon phase formation, and ordering.