Properties of glasses belonging to the Li2O-ZrO2-SiO2 system

The behaviour and some physical, chemical and thermal properties of Li2O-SiO2 glasses with ZrO2 additions (in the form of ZrSiO4) of up to 13.00 mol% in the as-quenched state were investigated with the aid of x-ray diffraction (XRD), FT-IR spectroscopy, thermal expansion, microhardness and density measurements as well as chemical durability measurements. Transparent glasses prepared by the addition of ZrO2 up to about 11.00 mol% were obtained. For successive addition of ZrO2 and decreasing Li2O/SiO2 ratio, the expansion coefficients revealed decreasing values from 12.60x10(-6) to 8.69x10(-6)degrees C-1. The glass transition and softening point temperatures of the glasses showed a reverse behaviour. By increasing the ZrO2 content in the base glasses the hardness and density values increased. However, while hardness increases even with the decrease of the Li2O/SiO2 ratio the density showed a contrary behaviour, i.e. it increased with the ZrO2 content but decreased when the Li2O/SiO2 ratio decreased, with the highest values of 6.73 GPa and 2.71 g/cm(3), respectively. On the other hand, the chemical durability, in the case of 30Li(2)O.70SiO(2) base glass, decreased with time in water solution and increased with ZrO2 content tending to be almost constant for ZrO2 contents higher than 4.76 mol% at 60 min and 6.98 mol% in the time range from 5 to 30 min, respectively.