|About this Abstract
||Materials Science & Technology 2020
||Journal of the American Ceramic Society Awards Symposium
||Substitutional Effect of Na2O with K2O on the Viscosity and Structure of CaO-SiO2-CaF2-based Mold Flux Systems
||MINSEOK SEO, Il Shon
|On-Site Speaker (Planned)
This study investigated the substitutional effect of Na2O with K2O on the viscosity and structure of molten CaO-SiO2-CaF2-based mold fluxes containing alkali-oxides at high temperature. The CaO/SiO2 mass ratio (C/S) was fixed at 0.8 and CaF2 was fixed at 10 mass pct. The total alkali-oxide was fixed at 20 mass pct. The K2O/(Na2O+K2O) mass ratio was modified between 0.0 and 1.0 to determine the effect on substitution. Viscosity of the systems were measured by rotating spindle method at high temperatures, the viscosity was found to increase with higher K2O/(Na2O+K2O). An apparent activation energy increased with higher K2O/(Na2O+K2O), from 96 to 154 kJ/mol. Structure of the as-quenched fluxes was studied using Raman spectroscopy, it is found that the mole fraction of Q3 increase, while the mole fractions of Q2 and Q0 decreased with higher K2O/(Na2O+K2O). The NBO/Si (nonbridged oxygen per silicon cation) decreased from 1.97 to 1.58 with increasing K2O/(Na2O+K2O).