PREPARATION OF OXYNITRIDE SILICON GLASSES .2. BULK OXYNITRIDE GLASSES OBTAINED BY HOT-PRESSING

Silica gels have been prepared from various precursors and heat treated under ammonia to obtain oxynitride gels. These gels are then transformed into bulk glasses by hot-pressing. The physical properties of these materials are reported. Glasses prepared from gels of triethoxysilane HSi(OC2H5)3 treated under ammonia are shown to contain up to 5 wt% nitrogen. Identical treatment of gels of tetramethoxysilane gives glasses containing less than 1 wt% nitrogen. Due to their high nitrogen content (SiON) glasses prepared from triethoxysilane gels exhibit physical and mechanical properties that are superior to those of the parent oxide glass. © 1990.