Sol-gel processing of carbidic glasses

Carbon incorporation into the silicate network results in the formation of rigid carbidic glasses with improved physical, mechanical and thermal prope rties. This generated great interest in the development of these heteroatom structured materials through different processing routes, In the present s tudies, sol-gel processing has been used to prepare silicon based glasses, especially oxycarbides through organic-inorganic hybrid gels by hydrolysis- condensation reactions in silicon alkoxides, 1,4-butanediol and furfuryl al cohol with an aim to introduce Si-C linkages in the precursors at sol level . The incorporation of these linkages has been studied using IR and NMR spe ctroscopy, These bonds, so introduced, are maintained throughout the proces sing, especially during pyrolysis to high temperatures. In FFA-TEOS system, copolymerization with optimized mol ratio of the two results in resinous m ass. This precursor on pyrolysis to 1000 degrees C results in Si-O-C type a morphous solid black mass. XRD studies on the materials heated to 1400 degr ees C exhibit presence of crystalline Si-C and cristobalites in amorphous S i-O-C mass. In organic-inorganic gel system, the pyrolysed mass exhibits ph ase stability up to much higher temperatures. The carbidic materials so pro duced have been found to exhibit good resistance against oxidation at 1000 degrees C.