Characteristics of the glass powders with low Pb content directly prepared by spray pyrolysis

Fine size glass powders with a 21.5 mol% PbO–50.5 mol% B2O3–16 mol% SiO2–12 mol% BaO–0.5 mol% CuO composition were directly prepared by spray pyrolysis. The glass powders prepared at 1000 °C had spherical shape and dense inner structure. The glass transition temperature (Tg) of the glass powders with the mean size of 0.84 μm was 493 °C. The number of voids in fired dielectric layers decreased with increasing the preparation temperature of the glass powders, and the dielectric layer formed from the glass powders prepared by spray pyrolysis at a temperature of 1000 °C had no voids inside the layer. The transmittances of the dielectric layer formed from the glass powders prepared at a temperature of 1000 °C were higher than 70% within the visible range. The mean sizes of the powders were changed from 0.36 to 1.0 μm when the concentrations of the spray solutions were changed from 0.03 to 1 M. The dielectric layers formed from the glass powders with small sizes had higher transmittances than those formed from the glass powders with large sizes.