Oxynitride Glasses Prepared from Gels and Melts
نویسندگان
چکیده
The structures of glasses prepared by melting mixtures of alkali borosilicate glass and silicon nitride powders and by ammonolysis of porous borosilicate gels were studied using Fourier transform infrared spectroscopy and combustion analysis. Whereas there was little evidence of nitride bond formation in the melt prepared glasses, Si-N and B-N bonding were observed in the gel-derlved glasses. It is proposed that these differences occur because Na20 and B203 are reduced by Si3N 4 in the melt to form SiO 2 + N 2 + metal. In comparison, ammonolysis of gels is a low temperature process (<I000°C) which occurs by Lewis acid adsorption and Lewis base attack on bridging oxygen bonds.
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