Changes of the Glass Structure in the Phase Splitting Process of Na<sub>2</sub>O-CaO-Al<sub>2</sub>O<sub>3</sub>-B<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub>-TiO<sub>2</sub> System

Abstract

This paper studied the change of glass phase splitting structure in Na2O-CaO- Al2O3-B2O3 -SiO2-TiO2 system. It discussed the change of two-phase composition and central ion coordination number of the phase splitting glass in the phase splitting process by using the means of EDS, SEM. The result indicates that the glass structure of two-phase changes significantly in the phase splitting process of this system. When the temperature is low, the glass net work is composed of [BO4], small quantity of [BO3] and large quantity of [AlO4] in the structure of alkali boron-rich phase, and the net adjustment ion is Ca2+ mainly; and then the glass net work is composed of [SiO4] and small quantity of [AlO4] in silicon-rich phase, and there are large quantity of net adjustment ion Na+ in the structure also. With the phase splitting temperature rising, the distribution of the net work central ion in two-phase retains unchanged, small quantity of the coodination number of Al3+ rising, [BO3] transfers to [BO4] gradually, at the same time, the net adjustment ion Na+ enters in alkali boron-rich phase, that is Na+ transfers to alkali boron-rich phase from silicon-rich phase. Along with the proceeding of phase splitting process, TiO2 concentrate and pricipitate at two-phase interface.