Characteristics of ZnO-B₂O₃-SiO₂ glass powders prepared by spray pyrolysis as densification promoter for BaTiO₃ ceramics

Spherical shape ZnO-B₂O₃-SiO₂ glass powders were prepared by spray pyrolysis. The optimum preparation temperature is 1500 °C when the flow rate of the carrier gas is 5 Lminute^-1. The mean size and geometric standard deviation of the glass powders is 0.78 μm and 1.38. The glass transition temperature of the glass powders is 489.1 °C. Melting of the ZnO-B₂O₃-SiO₂ glass powders occurs at 500 °C. On the other hand, some of the glass powders maintain a spherical morphology after firing at 500 °C. Complete melting of the glass powders occurs at firing temperatures of 600 and 700 °C, in which crystalline structures are observed. The dielectric constant of the BaTiO₃ pellet with 3 wt.% ZnO-B₂O₃-SiO₂ glass is 2682 at a firing temperature of 1000 °C.