Physicochemical Properties of Glasses of the Na2O-B2O3-SiO2-Fe2O3 System in the 6Na(2)O/70SiO(2) Section

摘要

Glasses of the 6Na(2)O-(24-x)B2O3-70SiO(2)-xFe(2)O(3) system with x ranging from 2 to 10 mol % are studied by dilatometry and X-ray powder diffractometry. The density of the glass is measured and the molar volume is calculated. The heat treatment of the glass is carried out at 550 and 700 degrees C for 96 and 2 h, respectively. Magnetite is formed in the heat-treated glasses and its content increases with the growth of the Fe2O3 concentration. In the glasses containing from 4 to 8 mol. % of Fe2O3, cristobalite is formed after treatment at 700 degrees C for 2 h. An increase in the density and the glass transition temperature and a decrease in the molar volume is observed with the growth of the iron oxide content.