STUDIES ON HIGH TEMPERATURE EVOLUTION OF POLYMER DERIVED NANO SiC CERAMICS

摘要

Borosiloxane oligomers, which give ceramic residue in the range of 70-78% (at 900℃) in inert atmosphere, were synthesized through the condensation of boric acid with allyltriethoxysilane without using any catalyst. The effect of concentration of the reactants on the processibility, yield and thermal stability of the product obtained was studied. All oligomers were pyrolysed at 900℃ followed by ceramic conversion after sintering at 1500℃ and 1650℃ in inert atmosphere and were characterized by XRD and spectroscopic techniques. Mixture of α and β-SiC are formed after sintering the samples at 1650℃ for 3 hours in inert atmosphere.