Sol-gel synthesis of SiBOC glasses

Silicon oxycarbide glass containing boron was prepared by pyrolysis of a sol-gel precursor in inert atmosphere. A structural characterization of the gel as well as of the SiBOC glass at various stages of the pyrolysis treatment has been performed. The precursor gels consists of =Si-O-Si= bonds with boron-rich regions in which =B-O-B= and/or =B-OH bonds are present. During the pyrolysis boron atoms are incorporated into the silicate network leading to the formation of a silicon(boron)oxycarbide glass. A further increase of the pyrolysis temperature results in the crystallization of SIG. The glass structure can thus be described as a borosilicate matrix with a fine dispersion beta-SIC nanocrystals. (C) 1998 Elsevier Science B.V.