Network Structure and Chemical Durability of Non-alkali Aluminoborosilicate Glasses Containing ZnO

Abstract

The structure and chemical durability of non-alkali aluminoborosilicate glasses with various contents of ZnO were investigated. As the replacement of MgO by ZnO increases from 0 to 3.2mol%, the average number of bridge oxygen per tetrahedron (BO/T) as a measure of network connectivity increases from 2.84 to 3.04, and the chemical durability improved. The weight loss ratio (WLR) of glass etched in 10vol% HF (20 °C, 20 min) solution decreased from 4.809 to 4.509, and in 5wt% NaOH (95 °C, 6 h) solution decreased from 1.201 to 0.994. The replacement of MgO by ZnO further increased to 6.4mol%, the value of BO/T decreased to 3.04 instead, and thus the chemical durability deteriorated. The WLR of HF-acid and NaOH-alkali corrosion increased to 6.683 and 1.994, respectively. The chemical durability shows strongly dependent on the network connectivity and exhibits mixed intermediate effects during the replacement of MgO by ZnO.