Effect of Na+ Ions on the Mechanical Properties of Lithium Aluminosilicate Glass

Abstract

A series of aluminosilicate glasses composed of 70SiO2-10Al2O3 -5K2O-15Li2O-xNaCl (x = 0.5,1.5,2.5,3.5 and 4.5wt.%) were successfully prepared by melt quenching method. The mechanical properties of aluminosilicate glasses with different NaCl doping contents were determined by Vickers hardness. With the addition of NaCl from 0.5wt.% to 3.5wt.%, the glass density and hardness decreased. Interestingly, Vickers hardness of the glass increased when the NaCl content increased by 4.5wt%. Raman test results show that the increase of NBO/T in the glass, that is, the decrease of the degree of polymerization of the glass network due to the breaking of Si-O-Si bonds. Since the Si-O-Si covalent bond is the strongest bond in the silicate glass,the glass structure tends to be loose, and the density and Vickers hardness decrease. Thus,we attribute the hardness increasing at 4.5wt% NaCl addition to the follow: Na +  enters the network pores and plays the role of network modification oxides.

Keywords: Hardness, NaCl adding, Lithium aluminosilicate glass, Structural relaxation, Melt-quenching method