Crystallization Behaviour Of Novel Silicon Boron Oxycarbide Glasses

Homogenous silicon boron oxycarbide (Si-B-O-C) glasses based on SiOxC4-x and BOyC3-y mixed environments were obtained by pyrolysis under inert atmosphere of sol-gel-derived precursors. Their high-temperature structural evolution from 1000-1500 deg C was followed using XRD, 29Si and 11B MAS NMR, and chemical analysis and compared with the behaviour of the parent boron-free Si-0-C glasses. The XRD study revealed that, for the Si-0-C and the Si-B-O-C systems, high temperature annealing led to the crystallization of nano-sized B-SiC into an amorphous Si02-based matrix.