The hardness and thermal expansion of erbium doped tellurite glass

Abstract

A series of glass based on (80-x) TeO2- 20 ZnO–x Er2O3 where 0<x≤ 2.5 mol % was prepared using melt quenching technique. The amorphosity of the glass was determined by X-ray diffraction (XRD) and the physical properties such as density and hardness was determined by means of Archimedes and Vickers Hardness method respectively. The thermal expansion was measured using dilatometric method. The fine glass rods were prepared using rotary ultrasonic machine (RUM) with diamond rods tools of 4 mm in diameter. Meanwhile, the surface roughness of the rods was measured using profilometry technique. The result of XRD patterns confirmed that the glass was in amorphous phase. It was found that, the density of the glass increased with increasing Er2O3 content. The range of density was found to be between 5.541g/cm3 and 5.663g/ cm3 . It was also found that as the amount of Er2O3 content increased, the hardness of glass decreased from 3.21 GPa to 2.277 GPa. Meanwhile, the thermal expansion coefficient of the glass was found to decrease from 15.8 X 10-06 °C-1 to 13.3 X10-06 °C-1 . It was found that the composition of 78.5 TeO2 – 20 ZnO – 1.5 Er2O3 exhibited the smallest thermal expansion coefficient and thus suitable for the fabrication of the glass rod. The surface roughness of the glass rods in the range of 2.15 μm to 1.18 μm was found to be dependent on the composition of the glass. In this work, the feed rate of 0.5, 1.0, 1.5 and 2.0 mm/min with spindle speed at 3000 rpm was the most suitable parameter to produce the desired glass rod.