The viscosity and the solubility of nitrogen for Y 2 O 3  Al 2 O 3  SiO 2 melts have been examined systematically. The effects of nitrogen content on viscosity for Y Al Si O N, and on Vicker's hardness of the oxynitride glasses have been examined. Though the viscosity of Y 2 O 3  Al 2 O 3  SiO 2 melts was decreased, and the solubility of nitrogen into the melts was increased with increasing the content of Y 2 O 3 for constant SiO 2 /Al 2 O 3 ratio, and with increasing the content of Al 2 O 3. These results indicate that Y 2 O 3 and also Al 2 O 3 behave as a network modifier. Therefore, the structural units for viscous flow become smaller, and the amount of non bridging oxygen increases in the melts as Y 2 O 3 or Al 2 O 3 content increase. The viscosity of Y Al Si O N glass melts and Vicker's hardness of oxynitride glasses increased with increasing the content of nitrogen. These results suggest that the substitution of nitrogen for oxygen may lead to larger structural units for viscous flow, and that the increase of cross linking produces a more rigid glass network.

No abstract

No abstract

No abstract