Characteristics of ZnO-B₂O₃-CaO-Na₂O-P₂O₅ glass powders prepared by spray pyrolysis

Fine-sized ZnO-B₂O₃-CaO-Na₂O-P₂O₅ glass powders with spherical shape were directly prepared by high temperature spray pyrolysis. The ZnO-B₂O₃-CaO-Na₂O-P₂O₅ powders prepared by spray pyrolysis at temperatures above 1200 °C had broad peaks at around 30° in the XRD patterns. The glass transition temperatures (T_g) of the glass powders obtained by spray pyrolysis at preparation temperatures between 900 °C and 1400 °C were near 480 °C regardless of the preparation temperatures. The dielectric layers formed from the glass powders prepared by spray pyrolysis at preparation temperatures above 1300 °C had clean surface and dense inner structure at the firing temperature of 580 °C. The transmittance of the dielectric layer formed from the glass powders obtained by spray pyrolysis at preparation temperature of 1400 °C was 90% at the firing temperature of 580 °C, in which the thickness of the dielectric layer was 13 μm. The UV cutoff edges gradually shift towards longer wavelength with increasing the preparation temperature of glass powders and the firing temperature of dielectric layers.