Papers by Keyword: Lead Free Glass

Abstract: The effect of varying the TiO2–content on the lead-free high refractive index glass based on 25 wt% barium carbonate added in replacing lead oxide was prepared and its physical, optical, and electrical properties were investigated. Seven glass samples were synthesized and characterized by using an analytical balance, a refractometer, a LCR meter and an X-ray diffractometer. Specific gravity, refractive index, and dielectric constant increased linearly as the increasing of the TiO2-content. The amorphous state of modification of glass structure due to TiO2 addition was confirmed.

Abstract: Lead glass that shows a high refractive index is the best known and most popular for radiation shielding glass. Due to the toxic of lead compounds on the human organisms as well as the environmental issues, lead free glass was fabricated by using some heavy elements such as barium and bismuth to replace lead. In this study, colorless lead free glass samples were prepared from 40 wt% local quartz sand and various concentration of BaCO3 (20-40 wt%) as the main compositions in order to study radiation shielding property. The glass mixtures were melted conventionally using electric furnace at the maximum temperature of 1250°C with 4 hr dwelling time. The gamma attenuation characteristics were studied for the photon energy of 662 keV from Cs-137. Density and refractive index were also determined. It was found that a variation of prepared glass samples can be produced both in terms of clarity and radiation shielding properties. The attenuation coefficients were linearly increased as the increase of BaCO3 content. The density and refractive index were also increased. The linear and mass attenuation coefficients of the glass sample containing 40 wt% BaCO3 were 0.234 cm-1 and 0.0726 cm2g-1. In conclusion, a low density glass samples will give rise less attenuation than a high density ones. It can be concluded that the lead-free high refractive index glass that is one of the environmental materials can be used as the gamma radiation shielding glass.

Abstract: Many difference useful and decorative articles have been made from glasses over the centuries, especially lead-containing glasses. Due to harmful effects of lead from glass fabrication process on human beings and considering the health as well as the environmental issues, many researchers tried to produce leadless glasses using some heavy chemical elements such as barium, bismuth and zirconium. Nowadays, barium compounds seemed to be satisfactory and to be able to increase the refractive index. For production of high quality crystal glasses with high refractive index in Thailand, most raw materials including high quality sand have been imported. Because, Thailand, in fact, is rich in many kinds of raw materials for glass manufacturing, therefore, this work is set up to study the fabrication of the lead-free high refractive index glasses using local sand and barite as the main raw materials. After complete melting, the physical and optical properties of the prepared glass samples were determined to compare these properties with those of glasses prepared from foreign sand. It was found that the prepared glasses produced from local raw materials were suitably for restoration, decoration, radiation shielding, as well as glass jewelry. These glasses can be considered as one of the environmental friendly materials.