Synthesis, structure and properties of PbO–PbF2–B2O3–SiO2 glasses

The structure, thermal and some physical properties of lead fluoroborate glasses containing 30 mol% SiO2 have been investigated by differential thermal analysis, X-ray diffraction and Fourier-transform infrared spectroscopy. The glasses were prepared by the conventional melt-quenching method. Fourier-transform infrared spectroscopy results showed that the network of these glasses consists mainly of BO3, BO4, SiO4, and PbO4 structural units. The thermal stability of the glass samples determined by differential thermal analysis was found to be about 80°C. Dilatometric measurements showed that the glass transition temperature and dilatometric softening temperature decrease with increasing lead content, whereas the coefficient of thermal expansion increases. The density and molar volume increased with the increase in lead content. The conductivity of the investigated glasses mainly depends on the mobility of F– and Pb2+ ions. The variation in volume resistance upon changing the composition has been correlated with the structural changes in the glass network. The results obtained in this study indicate that the investigated glasses can be potential candidates for advanced technologies as solder and sealing materials.