Na environment, conductivity, and water leaching of sodium alkaline earth silicate glass

Abstract

(Na₂O)_35.7(MO)_7.2(SiO₂)_57.1 and (Na₂O)_33.7(MO)_13.3(SiO₂)_53.4 glass materials that feature alkaline earth metals (M = Mg, Ca, Sr, Ba) were evaluated as Na⁺ conducting materials. Following glass synthesis from the melt under air at 1350 °C, Na environments, conductivity, and water leaching were investigated. ²³Na NMR spectrometry indicated Na–O distances decreased in the order M = Mg > Ca > Sr > Ba. The conductivities and activation energies of conduction respectively decreased and increased slightly in the order M = Mg, Ca, Sr, and Ba. Regardless of M, the conductivities and activation energies of conduction of (Na₂O)_33.7(MO)_13.3(SiO₂)_53.4 were lower and higher, respectively, than those of (Na₂O)_35.7(MO)_7.2(SiO₂)_57.1. Na leaching into water decreased in the order Ca < Mg < Sr < Ba. For each M, (Na₂O)_33.7(MO)_13.3(SiO₂)_53.4 was more resistant to leaching than (Na₂O)_35.7(MO)_7.2(SiO₂)_57.1.