The Estimation of the Iso-viscosity Lines in Molten CaF_2-CaO-SiO_2 System

摘要

Silicate melts consist of mixtures of five distinct types of structural units that have NBO/Si=0, 1, 2, 3, and 4 (NBO/ Si: nonbridging oxygen per silicon). In terms of a stoichio-metric expression, these units are described as SiO_4~(4-) (monomer), Si_2O_7~(6-) (dimmer), Si_2O_6~(4-) (chain unit), Si_2O_5~(2-) (sheet unit), and SiO_2 (three-dimensional structure) units. In the terminology commonly employed in NMR spec-troscopy, these structures are referred to as Q~0, Q~1, Q~2, Q~3, and Q~4, where the superscript refers to the number of bridging oxygen in a given structural unit.