Effects of Li2O replacing Na2O on glass forming, structure and properties of Na2O-MgO-Al2O3-SiO2 glass and glass-ceramics

Glasses and glass-ceramics in the xLi(2)O-(5-x)Na2O-20MgO-20Al(2)O(3)-54SiO(2) system have been prepared by using a conventional melt quenching technology and subsequently a two-step heat-treating method. The effects of Li2O replacing Na2O on crystallization, structural and electrochemical properties of Na2O-MgO-Al2O3-SiO2 glasses and glass-ceramics are studied. The results reveal that the glass forming ability, the bending strength, microhardness and ionic conductivity of parent glasses firstly decrease and then increase as Li2O gradually replacing Na2O from 0 mol.% to 5 mol.% due to the disconnection of Si-O-Si network, the suppression of the mobile species and the electrodynamic interaction between the Na-O- and Li-O- oscillating electric dipoles. The main crystalline phase of glass-ceramics is cordierite and the ionic conductivity is three orders of magnitude higher than that glasses. The ionic conductivity of MgO-Al2O3-SiO2 glass-ceramics with 5.0 mol.% Li2O replacing Na2O reaches the highest ionic conductivity (3.4 x 10(-6) S/cm), which provides a potential application for glass-ceramics as solid electrolytes in the future.

Automated summary

By replacing Na2O with Li2O in the xLi2O-(5-x)Na2O-20MgO-20Al2O3-54SiO2 system, the crystallization, physical properties, and conductivity of glasses were affected. The main crystalline phase of glass-ceramics is cordierite, and the ionic conductivity is significantly higher.