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

Abstract

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.

Effects of composition on the structure, thermal and some physical characteristics of Bi2O3-B2O3-ZnO-SiO2 glasses

“…The furnace temperature was set at 1050°C, and materials were melted for 45 minutes to ensure homogeneity. After melting, the molten glass was immediately poured into a stainless steel mold for shaping [14]. The glass was then subjected to a controlled annealing process to minimize the development of internal stresses and improve the structural integrity of the glass [15].…”

“…After melting, the molten glass was immediately poured into a stainless steel mold for shaping [14]. The glass was then subjected to a controlled annealing process to minimize the development of internal stresses and improve the structural integrity of the glass [15]. This involved placing the glass in a muffle furnace set at 360°C for a period of 5 hours to allow for slow and uniform cooling.…”

“…The finely ground powder was subsequently subjected to a sieving process. Specifically, the particles that successfully passed through a 270-mesh (53µm) sieve were collected for further DTA examination [14][15][16]. Differential Thermal Analysis was performed using a Derivatograf Q-1500D, which uses Pt crucibles to withstand the high temperatures involved in the analysis [17].…”

“…The peak temperature (T c ) of crystallization was identified as the apex of the exothermic peak, highlighting the point of most intense crystallization activity [13,18]. Subsequent studies aimed at detecting the presence of crystalline phases after the thermal treatment, which involved keeping the glass powder at the T c in an air atmosphere for five hours [15,16]. X-ray diffraction analysis using a DRON-3M instrument with Co-Kα radiation (1.79026 Å) confirmed the appearance of crystalline phases.…”

“…The study also utilized Fourier-transform infrared spectroscopy to obtain transmitting spectra of the samples, using a Thermo-Nicolet Avatar 370 FT-IR Spectrometer in the 1400-400 cm −1 range, with a 2 cm −1 resolution [14][15][16]. For this, glass powder was blended with potassium bromide (KBr) in a 2:200 ratio and compressed into 13 mm diameter pellets [19].…”